ORCID Profile
0000-0002-0879-1287
Current Organisation
University of Technology Sydney
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Medicinal and Biomolecular Chemistry | Cheminformatics and Quantitative Structure-Activity Relationships | Microbiology | Biologically Active Molecules | Veterinary Sciences | Systems Biology | Infectious Agents | Enzymes | Medical Biotechnology | Veterinary Microbiology (excl. Virology) | Veterinary Diagnosis and Diagnostics | Infectious Diseases | Sociology not elsewhere classified | Medical Biotechnology Diagnostics (incl. Biosensors) | Pharmacology and Pharmaceutical Sciences not elsewhere classified | Bioinformatics
ANZSRC Socio-Economic Objective (SEO)
Human Diagnostics | Human Pharmaceutical Treatments (e.g. Antibiotics) | Control of Animal Pests, Diseases and Exotic Species in Farmland, Arable Cropland and Permanent Cropland Environments | Reproductive System and Disorders | Human Biological Preventatives (e.g. Vaccines) | Expanding Knowledge in Technology | Veterinary Diagnostics | Sheep - Meat | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Heterologous overexpression and purification of cytochrome c′ from Rhodobacter capsulatus and a mutant (K42E) in the dimerization region. Mutation does not alter oligomerization but impacts the heme iron spin state and nitric oxide binding properties
Publisher: American Chemical Society (ACS)
Date: 21-03-2006
DOI: 10.1021/BI052605J
Abstract: Rhodobacter capsulatus cytochrome c' (RCCP) has been overexpressed in Escherichia coli, and its spectroscopic and ligand-binding properties have been investigated. It is concluded that the heterologously expressed protein is assembled correctly, as judged by UV-vis absorption, EPR, and resonance Raman (RR) spectroscopy of the unligated protein as well as forms in which the heme is ligated by CO or NO. To probe the oligomerization state of RCCP and its potential influence on heme reactivity, we have compared the properties of wild-type RCCP with a mutant (K42E) that lacks a salt bridge at the subunit interface. Analytical ultracentrifugation indicates that wild-type and K42E proteins are both monomeric in solution, contrary to the homodimeric structure of the crystalline state. Surprisingly, the K42E mutation produces a number of changes at the heme center (nearly 20 A distant), including perturbation of the ferric spin-state equilibrium and a change in the ferrous heme-nitrosyl complex from a six-coordinate/five-coordinate mixture to a predominantly five-coordinate heme-NO species. RR spectra indicate that ferrous K42E and wild-type RCCP both have relatively high Fe-His stretching frequencies, suggesting that the more favored five-coordinate heme-nitrosyl formation in K42E is not caused by a weaker Fe2+-His bond. Nevertheless, the altered reactivity of ferrous K42E with NO, together with its modified ferric spin state, shows that structural changes originating at the dimer interface can affect the properties of the heme center, raising the exciting possibility that intermolecular encounters at the protein surface might modulate the reactivity of cytochrome c' in vivo.
Editorial: Interplay of Infection and Microbiome.
Publisher: Frontiers Media SA
Date: 17-06-2020
Study protocol for The GOAL Trial: comprehensive geriatric assessment for frail older people with chronic kidney disease to increase attainment of patient-identified goals—a cluster randomised controlled trial
Publisher: Springer Science and Business Media LLC
Date: 30-05-2023
DOI: 10.1186/S13063-023-07363-4
Abstract: An increasing number of older people are living with chronic kidney disease (CKD). Many have complex healthcare needs and are at risk of deteriorating health and functional status, which can adversely affect their quality of life. Comprehensive geriatric assessment (CGA) is an effective intervention to improve survival and independence of older people, but its clinical utility and cost-effectiveness in frail older people living with CKD is unknown. The GOAL Trial is a pragmatic, multi-centre, open-label, superiority, cluster randomised controlled trial developed by consumers, clinicians, and researchers. It has a two-arm design, CGA compared with standard care, with 1:1 allocation of a total of 16 clusters. Within each cluster, study participants ≥ 65 years of age (or ≥ 55 years if Aboriginal or Torres Strait Islander (First Nations Australians)) with CKD stage 3–5/5D who are frail, measured by a Frailty Index (FI) of 0.25, are recruited. Participants in intervention clusters receive a CGA by a geriatrician to identify medical, social, and functional needs, optimise medication prescribing, and arrange multidisciplinary referral if required. Those in standard care clusters receive usual care. The primary outcome is attainment of self-identified goals assessed by standardised Goal Attainment Scaling (GAS) at 3 months. Secondary outcomes include GAS at 6 and 12 months, quality of life (EQ-5D-5L), frailty (Frailty Index – Short Form), transfer to residential aged care facilities, cost-effectiveness, and safety (cause-specific hospitalisations, mortality). A process evaluation will be conducted in parallel with the trial including whether the intervention was delivered as intended, any issue or local barriers to intervention delivery, and perceptions of the intervention by participants. The trial has 90% power to detect a clinically meaningful mean difference in GAS of 10 units. This trial addresses patient-prioritised outcomes. It will be conducted, disseminated and implemented by clinicians and researchers in partnership with consumers. If CGA is found to have clinical and cost-effectiveness for frail older people with CKD, the intervention framework could be embedded into routine clinical practice. The implementation of the trial’s findings will be supported by presentations at conferences and forums with clinicians and consumers at specifically convened workshops, to enable rapid adoption into practice and policy for both nephrology and geriatric disciplines. It has potential to materially advance patient-centred care and improve clinical and patient-reported outcomes (including quality of life) for frail older people living with CKD. ClinicalTrials.gov NCT04538157. Registered on 3 September 2020.
Molecular-viability testing and antimicrobial resistance in sexually transmitted infections.
Publisher: Elsevier BV
Date: 10-2023
Optimization of peptide-based inhibitors targeting the HtrA serine protease in Chlamydia: Design, synthesis and biological evaluation of pyridone-based and N-Capping group-modified analogues
Publisher: Elsevier BV
Date: 11-2021
DOI: 10.1016/J.EJMECH.2021.113692
Abstract: The obligate intracellular bacterium Chlamydia trachomatis (C. trachomatis) is responsible for the most common bacterial sexually transmitted infection and is the leading cause of preventable blindness, representing a major global health burden. While C. trachomatis infection is currently treatable with broad-spectrum antibiotics, there would be many benefits of a chlamydia-specific therapy. Previously, we have identified a small-molecule lead compound JO146 [Boc-Val-Pro-Val
Prevalence of Chlamydia trachomatis infection in Samoan women aged 18 to 29 and assessment of possible risk factors: a community-based study.
Publisher: Oxford University Press (OUP)
Date: 03-2015
Abstract: Knowledge about genital Chlamydia trachomatis (CT) infections in the Pacific is limited. In this study we investigated CT infection in Samoan women. We recruited women having unprotected sex aged 18 to 29 years from 41 Samoan villages. They completed a questionnaire and provided a urine s le for CT testing by PCR. Associations between CT infection and possible risk factors were explored using logistic regression. Altogether, 239 women were recruited 86 (36.0% weighted estimate of prevalence: 41.9% 95% CI: 33.4-50.5%) were positive for CT infection. A higher proportion of women aged 18 to 24 were positive (54/145 37.2%) than those aged 25 to 29 (32/94 34.0% p=0.20). Being single (OR 1.92 95% CI: 1.02-3.63) and having two or more lifetime sexual partners (OR 3.02 95% CI: 1.19-7.67) were associated with CT infection 27.6% of those with one lifetime partner were positive. Participants who had a previous pregnancy were less likely to be positive (OR 0.49 95% CI: 0.27-0.87). Primiparous and multiparous women were less likely to be positive than nulliparous women (OR 0.54 95% CI: 0.30-0.99 and OR 0.46 95% CI: 0.24-0.89, respectively). The prevalence of CT infection in these Samoan women is very high. Further studies, including investigating the prevalence of CT infection in men, and strategies for sustainable control are needed.
HtrA, RseP, and Tsp proteins do not elicit a pathology-related serum IgG response during sexually transmitted infection with Chlamydia trachomatis.
Publisher: Elsevier BV
Date: 06-2010
DOI: 10.1016/J.JRI.2010.02.007
Abstract: Chlamydia trachomatis sexually transmitted infection can cause serious reproductive morbidities. This study determined the prevalence of a serum IgG response to C. trachomatis putative stress response proteins in women, to test for an association with genital tract pathology. There was no significant association of serum IgG reactive with C. trachomatis HtrA, Tsp, or RseP with infection or pathology. cHSP60 serum IgG prevalence was significantly associated with infection compared to IgG negative infertile controls, but not with upper genital tract pathology. Serum IgG(1-4) antibody subclasses reactive with these antigens was not significantly different between cohorts, although different responses to each antigen were detected.
CHLAMYDIA TRACHOMATIS INFECTION IN SAMOAN WOMEN: PREVALENCE AND RISK FACTORS
Publisher: BMJ
Date: 09-2015
Human Chlamydia pneumoniae isolates demonstrate ability to recover infectivity following penicillin treatment whereas animal isolates do not.
Publisher: Oxford University Press (OUP)
Date: 06-02-2015
Abstract: Chlamydia pneumoniae strains have recently been demonstrated to have substantially different capacities to enter and recover from IFN-γ-induced persistence, depending on whether they are from human or animal host sources. Here, we examined the ability of two human and two animal strains to enter and be rescued from penicillin-induced persistence. The ability to form inclusions after the addition of penicillin was much reduced in the two animal isolates (koala LPCoLN, bandicoot B21) compared to the two human isolates (respiratory AR39 and heart A03). The penicillin treatment resulted in a dose-dependent loss of infectious progeny for all isolates, with the human strains failing to produce infectious progeny at lower doses of penicillin than the animal strains. The most remarkable finding however was the contrasting ability of the isolates to recover infectious progeny production after rescue by removal of the penicillin (at 72 h) and continued culture. The animal isolates both showed virtually no recovery from the penicillin treatment conditions. In contrast, the human isolates showed a significant ability to recovery infectivity, with the heart isolate (A03) showing the most marked recovery. Combined, these data further support the hypothesis that the ability to establish and recover from persistence appears to be enhanced in human C. pneumoniae strains compared to animal strains.
CtHtrA: the lynchpin of the chlamydial surface and a promising therapeutic target.
Publisher: Future Medicine Ltd
Date: 07-2017
Abstract: Chlamydia trachomatis is the most prevalent sexually transmitted bacterial infection worldwide and the leading cause of preventable blindness. Reports have emerged of treatment failure, suggesting a need to develop new antibiotics to battle Chlamydia infection. One possible candidate for a new treatment is the protease inhibitor JO146, which is an effective anti-Chlamydia agent that targets the CtHtrA protein. CtHtrA is a lynchpin on the chlamydial cell surface due to its essential and multifunctional roles in the bacteria's stress response, replicative phase of development, virulence and outer-membrane protein assembly. This review summarizes the current understanding of CtHtrA function and presents a mechanistic model that highlights CtHtrA as an effective target for anti-Chlamydia drug development.
Chromatin accessibility dynamics of Chlamydia-infected epithelial cells
Publisher: Cold Spring Harbor Laboratory
Date: 24-06-2019
DOI: 10.1101/681999
Abstract: Chlamydia are Gram-negative, obligate intracellular bacterial pathogens responsible for a broad spectrum of human and animal diseases. In humans, Chlamydia trachomatis is the most prevalent bacterial sexually transmitted infection worldwide and is the causative agent of trachoma (infectious blindness) in disadvantaged populations. Over the course of its developmental cycle, Chlamydia extensively remodels its intracellular niche and parasitises the host cell for nutrients, with substantial resulting changes to the host cell transcriptome and proteome. However, little information is available on the impact of chlamydial infection on the host cell epigenome and global gene regulation. Regions of open eukaryotic chromatin correspond to nucleosome-depleted regions, which in turn are associated with regulatory functions and transcription factor binding. We applied Formaldehyde-Assisted Isolation of Regulatory Elements enrichment followed by sequencing (FAIRE-Seq) to generate temporal chromatin maps of C. trachomatis -infected human epithelial cells in vitro over the chlamydial developmental cycle. We detected both conserved and distinct temporal changes to genome-wide chromatin accessibility associated with C. trachomatis infection. The observed differentially accessible chromatin regions, including several Clusters of Open Regulatory Elements (COREs) and temporally-enriched sets of transcription factors, may help shape the host cell response to infection. These regions and motifs were linked to genomic features and genes associated with immune responses, re-direction of host cell nutrients, intracellular signaling, cell-cell adhesion, extracellular matrix, metabolism and apoptosis. This work provides another perspective to the complex response to chlamydial infection, and will inform further studies of transcriptional regulation and the epigenome in Chlamydia -infected human cells and tissues
Laser-mediated rupture of chlamydial inclusions triggers pathogen egress and host cell necrosis
Publisher: Springer Science and Business Media LLC
Date: 10-03-2017
DOI: 10.1038/NCOMMS14729
Abstract: Remarkably little is known about how intracellular pathogens exit the host cell in order to infect new hosts. Pathogenic chlamydiae egress by first rupturing their replicative niche (the inclusion) before rapidly lysing the host cell. Here we apply a laser ablation strategy to specifically disrupt the chlamydial inclusion, thereby uncoupling inclusion rupture from the subsequent cell lysis and allowing us to dissect the molecular events involved in each step. Pharmacological inhibition of host cell calpains inhibits inclusion rupture, but not subsequent cell lysis. Further, we demonstrate that inclusion rupture triggers a rapid necrotic cell death pathway independent of BAK, BAX, RIP1 and caspases. Both processes work sequentially to efficiently liberate the pathogen from the host cytoplasm, promoting secondary infection. These results reconcile the pathogen's known capacity to promote host cell survival and induce cell death.
Detoxification enzyme activities (CYP1A1 and GST) in the skin of humpback whales as a function of organochlorine burdens and migration status
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.AQUATOX.2014.06.021
Abstract: The activities of glutathione-s-transferase (GST) and cytochrome P-450 1A1 (CYP1A1) enzymes were measured in freshly extracted epidermis of live-biopsied, migrating, southern hemisphere humpback whales (Megaptera novaeangliae). The two quantified enzyme activities did not correlate strongly with each other. Similarly, neither correlated strongly with any of the organochlorine compound groups previously measured in the superficial blubber of the s le biopsy core, likely reflecting the anticipated low levels of typical aryl-hydrocarbon receptor ligands. GST activity did not differ significantly between genders or between northward (early migration) or southward (late migration) migrating cohorts. Indeed, the inter-in idual variability in GST measurements was relatively low. This observation raises the possibility that measured activities were basal activities and that GST function was inherently impacted by the fasting state of the s led animals, as seen in other species. These results do not support the implementation of CYP1A1 or GST as effective biomarkers of organochlorine contaminant burdens in southern hemisphere populations of humpback whales as advocated for other cetacean species. Further investigation of GST activity in feeding versus fasting cohorts may, however, provide some insight into the fasting metabolism of these behaviourally adapted populations.
Random mutagenesis identifies novel genes involved in the secretion of antimicrobial, cell wall-lytic enzymes by Lactococcus lactis
Publisher: American Society for Microbiology
Date: 15-12-2008
DOI: 10.1128/AEM.00767-08
Abstract: Lactococcus lactis is a gram-positive bacterium that is widely used in the food industry and is therefore desirable as a candidate for the production and secretion of recombinant proteins. Previously, we generated a L. lactis strain that expressed and secreted the antimicrobial cell wall-lytic enzyme lysostaphin. To identify lactococcal gene products that affect the production of lysostaphin, we isolated and characterized mutants generated by random transposon mutagenesis that had altered lysostaphin activity. Out of 35,000 mutants screened, only one with no lysostaphin activity was identified, and it was found to contain an insertion in the lysostaphin expression cassette. Ten mutants with higher lysostaphin activity contained insertions in only four different genes, which encode an uncharacterized putative transmembrane protein (llmg_0609) (three mutants), an enzyme catalyzing the first step in peptidoglycan biosynthesis ( murA2 ) (five mutants), a putative regulator of peptidoglycan modification ( trmA ) (one mutant), and an uncharacterized enzyme possibly involved in ubiquinone biosynthesis (llmg_2148) (one mutant). These mutants were found to secrete larger amounts of lysostaphin than the control strain (MG1363[ lss ]), and the greatest increase in secretion was 9.8- to 16.1-fold, for the llmg_0609 mutants. The lysostaphin-oversecreting llmg_0609, murA2 , and trmA mutants were also found to secrete larger amounts of another cell wall-lytic enzyme (the Listeria monocytogenes bacteriophage endolysin Ply511) than the control strain, indicating that the phenotype is not limited to lysostaphin.
Cyclic-di-AMP synthesis by the diadenylate cyclase CdaA is modulated by the peptidoglycan biosynthesis enzyme GlmM in L actococcus lactis
Publisher: Wiley
Date: 15-12-2015
DOI: 10.1111/MMI.13281
Abstract: The second messenger cyclic-di-adenosine monophosphate (c-di-AMP) plays important roles in growth, virulence, cell wall homeostasis, potassium transport and affects resistance to antibiotics, heat and osmotic stress. Most Firmicutes contain only one c-di-AMP synthesizing diadenylate cyclase (CdaA) however, little is known about signals and effectors controlling CdaA activity and c-di-AMP levels. In this study, a genetic screen was employed to identify components which affect the c-di-AMP level in Lactococcus. We characterized suppressor mutations that restored osmoresistance to spontaneous c-di-AMP phosphodiesterase gdpP mutants, which contain high c-di-AMP levels. Loss-of-function and gain-of-function mutations were identified in the cdaA and gdpP genes, respectively, which led to lower c-di-AMP levels. A mutation was also identified in the phosphoglucosamine mutase gene glmM, which is commonly located within the cdaA operon in bacteria. The glmM I154F mutation resulted in a lowering of the c-di-AMP level and a reduction in the key peptidoglycan precursor UDP-N-acetylglucosamine in L. lactis. C-di-AMP synthesis by CdaA was shown to be inhibited by GlmM(I154F) more than GlmM and GlmM(I154F) was found to bind more strongly to CdaA than GlmM. These findings identify GlmM as a c-di-AMP level modulating protein and provide a direct connection between c-di-AMP synthesis and peptidoglycan biosynthesis.
SERO-EPIDEMIOLOGICAL ASSESSMENT INDICATES HIGH PREVALENCE OF C. TRACHOMATIS IN SAMOAN WOMEN WITH INFERTILITY
Publisher: BMJ
Date: 09-2015
Factors associated with pelvic inflammatory disease: A case series analysis of family planning clinic data.
Publisher: SAGE Publications
Date: 2022
DOI: 10.1177/17455057221112263
Abstract: We aimed to better understand factors associated with pelvic inflammatory disease in an outpatient setting. We analysed the characteristics of pelvic inflammatory disease cases diagnosed in an outpatient setting during 2018. There were 72 cases included in the final analysis. Of the pelvic inflammatory disease cases analysed, 55% were idiopathic, 22.2% were related to a sexually transmitted infection, and 22.2% had onset of symptoms within 6 weeks of a gynaecological procedure. Of the sexually transmitted infection–positive pelvic inflammatory disease cases, Chlamydia trachomatis was present in 56%, Mycoplasma genitalium was present in 38%, and Neisseria gonorrhoeae was present in 12.5% of cases. Many pelvic inflammatory disease cases had evidence of vaginal dysbiosis or features associated with vaginal flora disruption (recent antibiotic usage and/or vulvovaginal candidiasis). This case series highlights the burden of Mycoplasma genitalium pelvic inflammatory disease, and clinicians should be aware to include testing for this when diagnosing pelvic inflammatory disease. Our findings also support the hypothesis that host dysbiotic microbiota may contribute to pelvic inflammatory disease pathogenesis, with further research required to explore this proposition.
Is there a place for a molecular diagnostic test for pelvic inflammatory disease in primary care? An exploratory qualitative study.
Publisher: Public Library of Science (PLoS)
Date: 19-09-2022
DOI: 10.1371/JOURNAL.PONE.0274666
Abstract: There is currently no test for pelvic inflammatory disease (PID) that is non-invasive and sufficiently sensitive and specific. Clinicians must therefore diagnose PID clinically, ruling out medical emergencies and conducting pelvic examinations where possible. While guidelines state that clinicians should be prepared to over-diagnose PID, it remains an under-diagnosed condition, with severe reproductive health impacts when left untreated. This research is the first to consider the perspectives of end-users on the development of a diagnostic test for PID. Semi-structured live video feed online (Zoom) interviews were conducted with 11 clinicians and nine women (aged 18–30 years) in Australia to understand how a diagnostic test might be used, and what characteristics a test would need for it to be acceptable to clinicians and young women. Participants were recruited via researcher and university student networks. Reflexive thematic analysis was used to identify key themes relating to the acceptability and characteristics of a diagnostic test for PID. Seven general practitioners, four clinicians working in sexual health clinics, and nine young women (aged 21–27 years) were interviewed. Clinicians were aged between 31–58 years and were predominantly female. Clinicians recognised that the development of an accurate test to diagnose PID would be valuable to themselves and other clinicians, particularly those who lack experience diagnosing PID, and those working in certain settings, including emergency departments. They discussed how they might use a test to enhance their clinical assessment but highlighted that it would not replace clinical judgement. Clinicians also considered how a test would impact the patient experience and time to treatment, emphasising that it should be minimally invasive and have a quick turnaround time. Young women said a test would be acceptable if endorsed by a trustworthy clinician. PID remains a challenging diagnosis. Development of a minimally invasive and sufficiently accurate diagnostic test would be acceptable to young women and benefit some clinicians, although no test would completely replace an experienced clinician’s judgement in making a PID diagnosis.
Spotlight on…Wilhelmina M. Huston.
Publisher: Oxford University Press (OUP)
Date: 10-2019
Targeting the master regulator mTOR: a new approach to prevent the neurological of consequences of parasitic infections?
Publisher: Springer Science and Business Media LLC
Date: 21-11-2017
Chlamydia trachomatis Infection
Publisher: Springer International Publishing
Date: 2017
A Laboratory Competency Examination in Microbiology.
Publisher: Oxford University Press (OUP)
Date: 18-09-2018
Molecular evidence of Chlamydia pecorum and arthropod-associated Chlamydiae in an expanded range of marsupials
Publisher: Springer Science and Business Media LLC
Date: 09-10-2017
DOI: 10.1038/S41598-017-13164-Y
Abstract: The order Chlamydiales are biphasic intracellular bacterial pathogens infecting humans and domesticated animals. Wildlife infections have also been reported, with the most studied ex le being Chlamydia pecorum infections in the koala, an iconic Australian marsupial. In koalas, molecular evidence suggests that spill-over from C. pecorum infected livestock imported into Australia may have had a historical or contemporary role. Despite preliminary evidence that other native Australian marsupials also carry C. pecorum , their potential as reservoirs of this pathogen and other Chlamydia -related bacteria (CRBs) has been understudied. Mucosal epithelial s les collected from over 200 native Australian marsupials of different species and geographic regions across Australia were PCR screened for Chlamydiales . Previously described and genetically distinct C. pecorum genotypes and a range of 16S rRNA genotypes sharing similarity to different CRBs in the broader Chlamydiales order were present. One 16S rRNA Chlamydiales genotype recently described in Australian ticks that parasitise native Australian marsupials was also identified. This study provides further evidence that chlamydial infections are widespread in native fauna and that detailed investigations are required to understand the influence these infections have on host species conservation, but also whether infection spill-over plays a role in their epidemiology.
Chlamydial clinical isolates show subtle differences in persistence phenotypes and growth in vitro
Publisher: Microbiology Society
Date: 03-2021
Abstract: Urogenital Chlamydia trachomatis infection is the most common sexually transmitted bacterial infection throughout the world. While progress has been made to better understand how type strains develop and respond to environmental stress in vitro , very few studies have examined how clinical isolates behave under similar conditions. Here, we examined the development and persistence phenotypes of several clinical isolates, to determine how similar they are to each other, and the type strain C. trachomatis D/UW-3/Cx. The type strain was shown to produce infectious progeny at a higher magnitude than each of the clinical isolates, in each of the six tested cell lines. All chlamydial strains produced the highest number of infectious progeny at 44 h post-infection in the McCoy B murine fibroblast cell line, yet showed higher levels of infectivity in the MCF-7 human epithelial cell line. The clinical isolates were shown to be more susceptible than the type strain to the effects of penicillin and iron deprivation persistence models in the MCF-7 cell line. While subtle differences between clinical isolates were observed throughout the experiments conducted, no significant differences were identified. This study reinforces the importance of examining clinical isolates when trying to relate in vitro data to clinical outcomes, as well as the importance of considering the adaptations many type strains have to being cultured in vitro .
Chlamydia trachomatis responds to heat shock, penicillin induced persistence, and IFN-gamma persistence by altering levels of the extracytoplasmic stress response protease HtrA
Publisher: Springer Science and Business Media LLC
Date: 2008
Structure-activity analysis of peptidic Chlamydia HtrA inhibitors
Publisher: Elsevier BV
Date: 09-2019
DOI: 10.1016/J.BMC.2019.07.049
Abstract: Chlamydia trachomatis high temperature requirement A (CtHtrA) is a serine protease that performs proteolytic and chaperone functions in pathogenic Chlamydiae and is seen as a prospective drug target. This study details the strategies employed in optimizing the irreversible CtHtrA inhibitor JO146 [Boc-Val-Pro-Val
Immunoassay to categorize chlamydial inflammatory disease in women to develop biomarker from peptide derived stimulant and its response to cytokine
Publisher: Diva Enterprises Private Limited
Date: 2022
The efficacy of azithromycin and doxycycline for the treatment of rectal chlamydia infection: A systematic review and meta-analysis
Publisher: Oxford University Press (OUP)
Date: 29-01-2014
DOI: 10.1093/JAC/DKU574
Abstract: There are increasing concerns about treatment failure following treatment for rectal chlamydia with 1 g of azithromycin. A systematic review and meta-analysis was conducted to investigate the efficacy of 1 g of azithromycin as a single dose or 100 mg of doxycycline twice daily for 7 days for the treatment of rectal chlamydia. Medline, Embase, PubMed, Cochrane Controlled Trials Register, Australia New Zealand Clinical Trial Register and ClinicalTrials.gov were searched to the end of April 2014. Studies using 1 g of azithromycin or 7 days of doxycycline for the treatment of rectal chlamydia were eligible. Gender, diagnostic test, serovar, symptomatic status, other sexually transmitted infections, follow-up time, attrition and microbial cure were extracted. Meta-analysis was used to calculate pooled (i) azithromycin and doxycycline efficacy and (ii) efficacy difference. All eight included studies were observational. The random-effects pooled efficacy for azithromycin (based on eight studies) was 82.9% (95% CI 76.0%–89.8% I2 = 71.0% P & 0.01) and for doxycycline (based on five studies) was 99.6% (95% CI 98.6%–100% I2 = 0% P = 0.571), resulting in a random-effects pooled efficacy difference (based on five studies) of 19.9% (95% CI 11.4%–28.3% I2 = 48.5% P = 0.101) in favour of doxycycline. The efficacy of single-dose azithromycin may be considerably lower than 1 week of doxycycline for treating rectal chlamydia. However, the available evidence is very poor. Robust randomized controlled trials are urgently required.
Cytochrome P450 isozyme protein verified in the skin of southern hemisphere humpback whales (Megaptera novaeangliae): Implications for biochemical biomarker assessment
Publisher: Elsevier BV
Date: 04-2011
DOI: 10.1016/J.MARPOLBUL.2011.01.007
Abstract: Large mysticete whales represent a unique challenge for chemical risk assessment. Few epidemiological investigations are possible due to the low incidence of adult stranding events. Similarly their often extreme life-history adaptations of prolonged migration and fasting challenge exposure assumptions. Molecular biomarkers offer the potential to complement information yielded through tissue chemical analysis, as well as providing evidence of a molecular response to chemical exposure. In this study we confirm the presence of cytochrome P450 reductase (CPR) and cytochrome P450 isoenzyme 1A1 (CYP1A1) in epidermal tissue of southern hemisphere humpback whales (Megaptera novaeangliae). The detection of CYP1A1 in the integument of the humpback whale affords the opportunity for further quantitative non-destructive investigations of enzyme activity as a function of chemical stress.
Stereochemical basis for the anti-chlamydial activity of the phosphonate protease inhibitor JO146
Publisher: Elsevier BV
Date: 03-2018
A sponsorship action plan for increasing diversity in STEMM
Publisher: Wiley
Date: 10-02-2019
DOI: 10.1002/ECE3.4962
Chlamydia and Coxiella
Publisher: Wiley
Date: 19-08-2022
In vitro susceptibility of recent Chlamydia trachomatis clinical isolates to the CtHtrA inhibitor JO146
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.MICINF.2015.09.004
Abstract: The present study aimed to establish if a previously identified Chlamydia trachomatis HtrA (CtHtrA) inhibitor, JO146, is effective against currently circulating clinical isolates to validate if CtHtrA is a clinically relevant target for future therapeutic development. Inhibition of CtHtrA during the middle of the chlamydial replicative cycle until the completion of the cycle resulted in loss of infectious progeny for six unique clinical isolates representing different serovars. This supports the potential for CtHtrA to be a clinically relevant target for development of new therapeutics and suggests the importance of further investigation of JO146 as a lead compound.
Molecular pathogenesis of Chlamydia trachomatis
Publisher: Frontiers Media SA
Date: 18-10-2023
Bacterial proteases from the intracellular vacuole niche; Protease conservation and adaptation for pathogenic advantage
Publisher: Oxford University Press (OUP)
Date: 06-2010
Evolution to a chronic disease niche correlates with increased sensitivity to tryptophan availability for the obligate intracellular bacterium Chlamydia pneumoniae.
Publisher: American Society for Microbiology
Date: 28-03-2014
DOI: 10.1128/JB.01476-14
Life inside and out: making and breaking protein disulfide bonds inChlamydia
Publisher: Informa UK Limited
Date: 02-01-2019
Cervicovaginal microbiota and women’s health outcomes
Publisher: CSIRO Publishing
Date: 19-05-2021
DOI: 10.1071/MA21022
Abstract: The human cervicovaginal microbiome has an important role in the health and homoeostasis of the female reproductive tract. A eubiotic microbiome is typically dominated with lactic acid producing bacteria and is categorised into five community state types. Issues arise when the microbiome becomes dysbiotic, with the microbial composition shifting to contain a greater relative abundance of strict and facultative anaerobes. This shift will lead to several adverse changes in the vaginal environment including compromised epithelial cells, cell death, inflammation, and greater susceptibility to infection. These changes are associated with various adverse outcomes including infections, preterm birth, and infertility. In this review, we discuss how the cervicovaginal microbiome influences these outcomes and possible future directions of treatment and research.
Cloacal and Ocular Microbiota of the Endangered Australian Northern Quoll
Publisher: MDPI AG
Date: 12-07-2018
DOI: 10.3390/MICROORGANISMS6030068
Abstract: The Australian northern quoll is an important predatory marsupial carnivore that is currently endangered due to inappropriate fire regimes, predation, and the spread of invasive cane toads. The microbiota of Australian marsupials has not been extensively studied, but is thought to play a role in their health. This study provides an initial characterization of the cloacal microbiota of the northern quoll, as well as other marsupials including possums and kangaroos which were opportunistically s led. The northern quoll cloaca microbiota was dominated by Enterococcus and Lactobacillus and had a relatively high proportion of members of the Proteobacteria phylum, which has been observed in other carnivorous marsupials. The ersity and structure of the microbiota was not influenced by presence of Chlamydiales which are intracellular bacteria and potential pathogens. The microbiota of the other marsupials was quite varied, which may be related to their health status. Characterization of the northern quoll microbiota will help to better understand the biology of this endangered animal.
Development and evaluation of a multi-antigen peptide ELISA for the diagnosis of Chlamydia trachomatis-related infertility in women.
Publisher: Microbiology Society
Date: 09-2016
DOI: 10.1099/JMM.0.000311
The temperature activated HtrA protease from pathogen Chlamydia trachomatis acts as both a chaperone and protease at 37 °C
Publisher: Wiley
Date: 26-06-2007
DOI: 10.1016/J.FEBSLET.2007.06.039
Abstract: Characterization of the protease, HtrA, from pathogen Chlamydia trachomatis is presented. The purified recombinant protein was a serine endoprotease, specific for unfolded proteins, and temperature activated above 34 degrees C. Chaperone activity was observed, although this appeared target-dependent. Inactive protease (S247A) was able to chaperone insulin B-chain, irrespective of temperature, but at 30 degrees C only HtrA and not S247A displayed significant chaperone activity for alpha-lactalbumin. These data demonstrate that chaperone activity may involve functional protease domain and that C. trachomatis HtrA functions as both a chaperone and protease at 37 degrees C. These properties are consistent with the developmental cycle of this obligate intracellular bacterium.
DISTINCT GROWTH AND GENOME PROFILES ARE PRESENT IN CLINICAL ISOLATES FROM WOMEN WHO FAIL TO RESOLVE GENITAL CHLAMYDIA INFECTION AFTER AZITHROMYCIN TREATMENT
Publisher: BMJ
Date: 09-2015
Proof of concept: A bioinformatic and serological screening method for identifying new peptide antigens for Chlamydia trachomatis related sequelae in women
Publisher: Elsevier BV
Date: 2013
Human and pathogen factors associated with chlamydia trachomatis-related infertility in women
Publisher: American Society for Microbiology
Date: 10-2015
DOI: 10.1128/CMR.00035-15
Abstract: Chlamydia trachomatis is the most common bacterial sexually transmitted pathogen worldwide. Infection can result in serious reproductive pathologies, including pelvic inflammatory disease, ectopic pregnancy, and infertility, in women. However, the processes that result in these reproductive pathologies have not been well defined. Here we review the evidence for the human disease burden of these chlamydial reproductive pathologies. We then review human-based evidence that links Chlamydia with reproductive pathologies in women. We present data supporting the idea that host, immunological, epidemiological, and pathogen factors may all contribute to the development of infertility. Specifically, we review the existing evidence that host and pathogen genotypes, host hormone status, age of sexual debut, sexual behavior, coinfections, and repeat infections are all likely to be contributory factors in development of infertility. Pathogen factors such as infectious burden, treatment failure, and tissue tropisms or ascension capacity are also potential contributory factors. We present four possible processes of pathology development and how these processes are supported by the published data. We highlight the limitations of the evidence and propose future studies that could improve our understanding of how chlamydial infertility in women occurs and possible future interventions to reduce this disease burden.
Environmental Legionella spp. collected in urban test sites of South East Queensland, Australia, are virulent to human macrophages in vitro
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.RESMIC.2015.10.007
Abstract: Legionellae are frequent contaminants of potable water supplies, resulting in sporadic infections and occasional outbreaks. Isolates of Legionella were collected from urban test sites within South East Queensland and evaluated for their virulence potential in vitro. Two strains (from the species Legionella londiniensis and Legionella quinlivanii) were demonstrated to have the ability to infect human macrophages, while a strain from the species Legionella anisa did not maintain an infection over the same time course. This suggests that the spectrum of urban environmentally associated Legionella with potential to cause human disease might be greater than currently considered.
The active site residue V266 of chlamydial HtrA is critical for substrate binding during both in vitro and in vivo conditions
Publisher: S. Karger AG
Date: 2012
DOI: 10.1159/000336312
Abstract: HtrA is a complex, multimeric chaperone and serine protease important for the virulence and survival of many bacteria. i Chlamydia trachomatis /i is an obligate, intracellular bacterial pathogen that is responsible for severe disease pathology. i C. trachomatis /i HtrA (CtHtrA) has been shown to be highly expressed in laboratory models of disease. In this study, molecular modelling of CtHtrA protein active site structure identified putative S1–S3 subsite residues I242, I265, and V266. These residues were altered by site-directed mutagenesis, and these changes were shown to considerably reduce protease activity on known substrates and resulted in a narrower and distinct range of substrates compared to wild type. Bacterial two-hybrid analysis revealed that CtHtrA is able to interact in vivo with a broad range of protein sequences with high affinity. Notably, however, the interaction was significantly altered in 35 out of 69 clones when residue V266 was mutated, indicating that this residue has an important function during substrate binding.
Uptake and Depuration Kinetics Influence Microplastic Bioaccumulation and Toxicity in Antarctic Krill (Euphausia superba)
Publisher: American Chemical Society (ACS)
Date: 03-02-2018
Abstract: The discarding of plastic products has led to the ubiquitous occurrence of microplastic particles in the marine environment. The uptake and depuration kinetics of ingested microplastics for many marine species still remain unknown despite its importance for understanding bioaccumulation potential to higher trophic level consumers. In this study, Antarctic krill ( Euphausia superba) were exposed to polyethylene microplastics to quantify acute toxicity and ingestion kinetics, providing insight into the bioaccumulation potential of microplastics at the first-order consumer level. In the 10 day acute toxicity assay, no mortality or dose-dependent weight loss occurred in exposed krill, at any of the exposure concentrations (0, 10, 20, 40, or 80% plastic diet). Krill exposed to a 20% plastic diet for 24 h displayed fast uptake (22 ng mg
CXCL10, CXCL11, HLA-A and IL-1β are induced in peripheral blood mononuclear cells from women with Chlamydia trachomatis related infertility.
Publisher: Oxford University Press (OUP)
Date: 27-10-2016
Abstract: Chlamydia trachomatis infections can result in the development of serious sequelae such as pelvic inflammatory disease and tubal infertility. In this study, peripheral blood mononuclear cells from women who were undergoing or had recently undergone IVF treatment were cultured ex vivo with C. trachomatis to identify the immune responses associated with women who had serological evidence of a history of Chlamydia infection. Cytokines secreted into the supernatant from the cultures were measured using ELISA, and the level of IL-1β was found to be significantly higher in Chlamydia positive women than Chlamydia negative women. qRT-PCR analysis of the expression of 88 immune-related genes showed trends towards an upregulation of CXCL10, CXCL11 and HLA-A in Chlamydia positive women compared with Chlamydia negative women. These findings support that some women launch a more marked proinflammatory response upon infection with C. trachomatis and this may be associated with why C. trachomatis induces infertility in some infected women.
Cervicovaginal microbiota, women's health, and reproductive outcomes
Publisher: Elsevier BV
Date: 08-2018
Characterization of in vitro Chlamydia muridarum persistence and utilization in an in vivo mouse model of Chlamydia vaccine.
Publisher: Wiley
Date: 18-02-2013
DOI: 10.1111/AJI.12093
Abstract: Chlamydia trachomatis genital tract infections are easily treated with antibiotics however, the majority of infections are asymptomatic and therefore untreated, highlighting the need for a vaccine. Because most infections are asymptomatic, vaccination could potentially be administered to in iduals who may have an acute infection at that time. In such in iduals, the effect of vaccination on the existing infection is unknown however, one potential outcome could be the development of a persistent infection. In vitro chlamydial persistence has been well characterized in various strains however, there have been no reported studies in C. muridarum. We performed ultrastructural characterization and transcriptome analysis of selected genes. We then used the transcriptional profiles of the selected genes to examine whether intranasal immunization of mice during an active genital infection would induce persistence in the upper reproductive tract of female mice. We found that persistence developed in the oviducts of mice as a result of immunization. This is a significant finding, not only because it is the first time that C. muridarum persistence has been characterized in vitro, but also due to the fact that there is a minimal characterization of in vivo persistence of any chlamydial species. This highlights the importance of the timing of vaccination in in iduals.
Dual RNA-seq analysis of in vitro infection multiplicity and RNA depletion methods in Chlamydia-infected epithelial cells
Publisher: Springer Science and Business Media LLC
Date: 17-05-2021
DOI: 10.1038/S41598-021-89921-X
Abstract: Dual RNA-seq experiments examining viral and bacterial pathogens are increasing, but vary considerably in their experimental designs, such as infection rates and RNA depletion methods. Here, we have applied dual RNA-seq to Chlamydia trachomatis infected epithelial cells to examine transcriptomic responses from both organisms. We compared two time points post infection (1 and 24 h), three multiplicity of infection (MOI) ratios (0.1, 1 and 10) and two RNA depletion methods (rRNA and polyA). Capture of bacterial-specific RNA were greatest when combining rRNA and polyA depletion, and when using a higher MOI. However, under these conditions, host RNA capture was negatively impacted. Although it is tempting to use high infection rates, the implications on host cell survival, the potential reduced length of infection cycles and real world applicability should be considered. This data highlights the delicate nature of balancing host–pathogen RNA capture and will assist future transcriptomic-based studies to achieve more specific and relevant infection-related biological insights.
Evidence of a conserved role for Chlamydia HtrA in the replication phase of the chlamydial developmental cycle
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.MICINF.2014.07.003
Abstract: Identification of the HtrA inhibitor JO146 previously enabled us to demonstrate an essential function for HtrA during the mid-replicative phase of the Chlamydia trachomatis developmental cycle. Here we extend our investigations to other members of the Chlamydia genus. C. trachomatis isolates with distinct replicative phase growth kinetics showed significant loss of viable infectious progeny after HtrA was inhibited during the replicative phase. Mid-replicative phase addition of JO146 was also significantly detrimental to Chlamydia pecorum, Chlamydia suis and Chlamydia cavie. These data combined indicate that HtrA has a conserved critical role during the replicative phase of the chlamydial developmental cycle.
The epidemiology of chlamydia trachomatis organism load during genital infection: A systematic review
Publisher: Oxford University Press (OUP)
Date: 09-12-2015
Abstract: The role of organism load in Chlamydia trachomatis infection is not well understood. We conducted a systematic review to investigate the epidemiology of C. trachomatis organism load in human genital chlamydia infection. Embase, PubMed, and Medline databases were searched for literature published through August 2014. English-language publications that quantified load in humans were eligible. Participant characteristics and laboratory data were extracted. A total of 737 records were identified, and 29 publications involving 40 883 participants were included. In women, load was highest for cervical swabs and lowest for urine specimens. In men, load was highest for rectal swabs and similar for urethral swabs and urine specimens. Evidence of any association between load and age, serovar, risk of transmission, hormone levels, and concurrent sexually transmitted infections was inconsistent. Eight of 9 culture-based studies found an association between load and signs and symptoms, in contrast with only 3 of 8 nucleic acid lification test (NAAT)-based studies (P = .03). Chlamydia organism load varies by specimen type and site of s ling, and viable chlamydia organism load may be a more important indicator of severity of infection than total load measured by NAAT.
Increased sensitivity to tryptophan bioavailability is a positive adaptation by the human strains of Chlamydia pneumoniae.
Publisher: Wiley
Date: 22-07-2014
DOI: 10.1111/MMI.12701
Abstract: One of the most significant activities induced by interferon-gamma against intracellular pathogens is the induction of IDO (indoleamine 2,3-dioxygenase) expression, which subsequently results in the depletion of tryptophan. We tested the hypothesis that human strains of Chlamydia pneumoniae are more sensitive to tryptophan limitation than animal C. pneumoniae strains. The human strains were significantly more sensitive to IFN-γ than the animal strains in a lung epithelia cell model (BEAS-2B), with exposure to 1 U ml(-1) IFN-γ resulting in complete loss of infectious yield of human strains, compared to the animal strains where reductions in infectious progeny were around 3.5-4.0 log. Strikingly, the IFN-γ induced loss of ability to form infectious progeny production was completely rescued by removal of the IFN-γ and addition of exogenous tryptophan for the human strains, but not the animal strains. In fact, a human heart strain was more capable of entering a non-infectious, viable persistent stage when exposed to IFN-γ and was also more effectively rescued, compared to a human respiratory strain. Exquisite susceptibility to IFN-γ, specifically due to tryptophan availability appears to be a core adaptation of the human C. pneumoniae strains, which may reflect the chronic nature of their infections in this host.
Vaccination to protect against infection of the female reproductive tract
Publisher: Informa UK Limited
Date: 2012
DOI: 10.1586/ECI.11.80
Abstract: Infection of the female genital tract can result in serious morbidities and mortalities from reproductive disability, pelvic inflammatory disease and cancer, to impacts on the fetus, such as infant blindness. While therapeutic agents are available, frequent testing and treatment is required to prevent the occurrence of the severe disease sequelae. Hence, sexually transmitted infections remain a major public health burden with ongoing social and economic barriers to prevention and treatment. Unfortunately, while there are two success stories in the development of vaccines to protect against HPV infection of the female reproductive tract, many serious infectious agents impacting on the female reproductive tract still have no vaccines available. Vaccination to prevent infection of the female reproductive tract is an inherently difficult target, with many impacting factors, such as appropriate vaccination strategies/mechanisms to induce a suitable protective response locally in the genital tract, variation in the local immune responses due to the hormonal cycle, selection of vaccine antigen(s) that confers effective protection against multiple variants of a single pathogen (e.g., the different serovars of Chlamydia trachomatis) and timing of the vaccine administration prior to infection exposure. Despite these difficulties, there are numerous ongoing efforts to develop effective vaccines against these infectious agents and it is likely that this important human health field will see further major developments in the next 5 years.
Purification and characterization of cytochrome c′ from Neisseria meningitidis
Publisher: Portland Press Ltd.
Date: 02-2005
DOI: 10.1042/BST0330187
Abstract: Cytochrome c′, a c-type cytochrome with unique spectroscopic and magnetic properties, has been characterized in a variety of denitrifying and photosynthetic bacteria. Cytochrome c′ has a role in defence and/or removal of NO but the mechanism of action is not clear. To examine the function of cytochrome c′ from Neisseria meningitidis, the protein was purified after heterologous overexpression in Escherichia coli. The electronic spectra of the oxidized c′ demonstrated a pH-dependent transition (over the pH range of 6–10) typical of known c′-type cytochromes. Interestingly, the form in which NO is supplied determines the redox state of the resultant haem-nitrosyl complex. Fe(III)–NO complexes were formed when Fe(II) or Fe(III) cytochrome c′ was sparged with NO gas, whereas an Fe(II)–NO complex was generated when NO was supplied using DEA NONOate (diazeniumdiolate).
Factors associated with anorectal Chlamydia trachomatis or Neisseria gonorrhoeae test positivity in women: a systematic review and meta-analysis.
Publisher: BMJ
Date: 16-05-2019
DOI: 10.1136/SEXTRANS-2018-053950
Abstract: There has been considerable discussion about anorectal Chlamydia trachomatis (CT) in women, with some calling for anorectal CT screening, but little about anorectal Neisseria gonorrhoeae (NG). Given that urogenital NG is more strongly associated with pelvic inflammatory disease, this is an evidence gap. This systematic review and meta-analysis investigates the associations between anorectal CT in women and CT positivity at other sites (urogenital/oropharyngeal) and with anal intercourse, and compares these with anorectal NG within the same study populations. Electronic databases were searched for English-language studies published to October 2018 using the following terms: (“Chlamydia” OR “ Chlamydia trachomatis ”) AND ((“anal” OR “rect*” OR “anorect*”) OR (“extra?genital” OR “multi?site”)). Studies were included if anorectal NG data were available. Random-effects meta-analyses calculated pooled estimates heterogeneity was investigated using meta-regression. 25 studies were eligible. Anorectal CT positivity ranged from 0% to 17.5%, with a summary estimate of 8.0% (95% CI 7.0 to 9.1 I 2 =88.5%). Anorectal NG positivity ranged from 0% to 17.0%, with a summary estimate of 2.1% (95% CI 1.6 to 2.8 I 2 =92.7%). The association between urogenital and anorectal positivity was stronger for NG than CT (summary prevalence ratio (PR)=89.3 (95% CI 53.1 to 150.3 I 2 =80.1%), PR=32.2 (95% CI 25.6 to 40.7 I 2 =70.3%), respectively), and between oropharyngeal and anorectal positivity it was stronger for NG than CT (PR=34.8 (95% CI 10.2 to 118.2 I 2 =89.9%), PR=8.8 (95% CI 6.8 to 11.5 I 2 =58.1%), respectively). Anal intercourse was associated with anorectal NG (PR=4.3 95% CI 2.2 to 8.6 I 2 =0.0%) but not with anorectal CT (PR=1.0 95% CI 0.7 to 1.4 I 2 =0.0%). Anorectal CT is more common than anorectal NG, but anorectal NG is more strongly associated with anal intercourse, urogenital and oropharyngeal NG, suggesting that ongoing discussion about anorectal CT should also include NG. Longitudinal data are required to further understanding of the aetiology of anorectal STIs and assess whether anorectal screening is needed in women. CRD42df017080188.
Identification of a serine protease inhibitor which causes inclusion vacuole reduction and is lethal to C hlamydia trachomatis
Publisher: Wiley
Date: 12-07-2013
DOI: 10.1111/MMI.12306
Abstract: The mechanistic details of the pathogenesis of Chlamydia, an obligate intracellular pathogen of global importance, have eluded scientists due to the scarcity of traditional molecular genetic tools to investigate this organism. Here we report a chemical biology strategy that has uncovered the first essential protease for this organism. Identification and application of a unique CtHtrA inhibitor (JO146) to cultures of Chlamydia resulted in a complete loss of viable elementary body formation. JO146 treatment during the replicative phase of development resulted in a loss of Chlamydia cell morphology, diminishing inclusion size, and ultimate loss of inclusions from the host cells. This completely prevented the formation of viable Chlamydia elementary bodies. In addition to its effect on the human Chlamydia trachomatis strain, JO146 inhibited the viability of the mouse strain, Chlamydia muridarum, both in vitro and in vivo. Thus, we report a chemical biology approach to establish an essential role for Chlamydia CtHtrA. The function of CtHtrA for Chlamydia appears to be essential for maintenance of cell morphology during replicative the phase and these findings provide proof of concept that proteases can be targeted for antimicrobial therapy for intracellular pathogens.
In vitro rescue of genital strains of Chlamydia trachomatis from interferon-γ and tryptophan depletion with indole-positive, but not indole-negative Prevotella spp.
Publisher: Springer Science and Business Media LLC
Date: 12-2016
A retrospective cohort study examining STI testing and perinatal records demonstrates reproductive health burden of chlamydia and gonorrhea.
Publisher: Oxford University Press (OUP)
Date: 08-2020
Abstract: Adverse reproductive health outcomes, such as pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility, have been associated with Chlamydia trachomatis and Neisseria gonorrhoea infections. These reproductive health outcomes could be complemented by measuring subsequent pregnancies to assess impact on fertility. The study design was a cohort study of women in Queensland (QLD), Australia, using data linkage methods to link chlamydia and/or gonorrhea testing records (including an unexposed group undergoing full blood count tests 2000 and 2005) with the QLD Perinatal Registry (2000–2013). The cohort included 132 962 women, with 69 533 records of pregnancies. Women in the exposed group, with no prior pregnancy, had a reduced odds of a pregnancy during the follow up of the study (20-year-old (at 2005) aOR 0.91 95% CI 0.87–0.95, and 25-year-old aOR 0.71 95% CI 0.68–0.75). Women in the exposed group with a prior pregnancy had increased odds of pregnancy during the follow up of the study (20-year-old (at 2005) aOR 1.72 95% CI 1.59–1.86, and 25-year-old aOR 1.35 95% CI 1.26–1.45). Our data provides further evidence at a population level of the significant impact on reproductive outcomes associated with chlamydia and gonorrhea.
Survey of ferroxidase expression and siderophore production in clinical isolates of Pseudomonas aeruginosa
Publisher: American Society for Microbiology
Date: 06-2004
DOI: 10.1128/JCM.42.6.2806-2809.2004
Abstract: Ferroxidase (encoded by the mco gene), a component of a ferrous iron uptake pathway in Pseudomonas aeruginosa , was detected in all of the 35 respiratory clinical isolates surveyed in contrast, considerable variation in siderophore expression was observed. The ubiquitous expression of this periplasmic ferroxidase suggests that it plays a key role in iron uptake in this opportunistic pathogen.
The protease inhibitor JO146 demonstrates a critical role for CtHtrA for Chlamydia trachomatis reversion from penicillin persistence
Publisher: Frontiers Media SA
Date: 2013
AZITHROMYCIN TREATMENT FAILURE IN WOMEN INFECTED WITH GENITAL CHLAMYDIA INFECTION
Publisher: BMJ
Date: 09-2015
The IL-6 response to Chlamydia from primary reproductive epithelial cells is highly variable and may be involved in differential susceptibility to the immunopathological consequences of chlamydial infection
Publisher: Springer Science and Business Media LLC
Date: 15-11-2013
Abstract: Chlamydia trachomatis infection results in reproductive damage in some women. The process and factors involved in this immunopathology are not well understood. This study aimed to investigate the role of primary human cellular responses to chlamydial stress response proteases and chlamydial infection to further identify the immune processes involved in serious disease sequelae. Laboratory cell cultures and primary human reproductive epithelial cultures produced IL-6 in response to chlamydial stress response proteases (CtHtrA and CtTsp), UV inactivated Chlamydia, and live Chlamydia . The magnitude of the IL-6 response varied considerably (up to 1000 pg ml -1 ) across different primary human reproductive cultures. Thus different levels of IL-6 production by reproductive epithelia may be a determinant in disease outcome. Interestingly, co-culture models with either THP-1 cells or autologous primary human PBMC generally resulted in increased levels of IL-6, except in the case of live Chlamydia where the level of IL-6 was decreased compared to the epithelial cell culture only, suggesting this pathway may be able to be modulated by live Chlamydia . PBMC responses to the stress response proteases (CtTsp and CtHtrA) did not significantly vary for the different participant cohorts. Therefore, these proteases may possess conserved innate PAMPs. MAP kinases appeared to be involved in this IL-6 induction from human cells. Finally, we also demonstrated that IL-6 was induced by these proteins and Chlamydia from mouse primary reproductive cell cultures (BALB/C mice) and mouse laboratory cell models. We have demonstrated that IL-6 may be a key factor for the chlamydial disease outcome in humans, given that primary human reproductive epithelial cell culture showed considerable variation in IL-6 response to Chlamydia or chlamydial proteins, and that the presence of live Chlamydia (but not UV killed) during co-culture resulted in a reduced IL-6 response suggesting this response may be moderated by the presence of the organism.
DETERMINATION OF ANTIBIOTIC SUSCEPTIBILITY AND EFFICACY BY VITA-PCR
Publisher: BMJ Publishing Group Ltd
Date: 07-2019
Detection of Chlamydia trachomatis mRNA using digital PCR as a more accurate marker of viable organism.
Publisher: Springer Science and Business Media LLC
Date: 14-08-2018
Structural basis for the hijacking of endosomal sorting nexin proteins by Chlamydia trachomatis
Publisher: eLife Sciences Publications, Ltd
Date: 22-02-2017
DOI: 10.7554/ELIFE.22311
Abstract: During infection chlamydial pathogens form an intracellular membrane-bound replicative niche termed the inclusion, which is enriched with bacterial transmembrane proteins called Incs. Incs bind and manipulate host cell proteins to promote inclusion expansion and provide camouflage against innate immune responses. Sorting nexin (SNX) proteins that normally function in endosomal membrane trafficking are a major class of inclusion-associated host proteins, and are recruited by IncE/CT116. Crystal structures of the SNX5 phox-homology (PX) domain in complex with IncE define the precise molecular basis for these interactions. The binding site is unique to SNX5 and related family members SNX6 and SNX32. Intriguingly the site is also conserved in SNX5 homologues throughout evolution, suggesting that IncE captures SNX5-related proteins by mimicking a native host protein interaction. These findings thus provide the first mechanistic insights both into how chlamydial Incs hijack host proteins, and how SNX5-related PX domains function as scaffolds in protein complex assembly.
Structure and Metal Binding Properties of Chlamydia trachomatis YtgA.
Publisher: American Society for Microbiology
Date: 06-12-2019
DOI: 10.1128/JB.00580-19
Abstract: Chlamydia trachomatis is the most common bacterial sexually transmitted infection in developed countries, with an estimated global prevalence of 4.2% in the 15- to 49-year age group. Although infection is asymptomatic in more than 80% of infected women, about 10% of cases result in serious disease. Infection by C. trachomatis is dependent on the ability to acquire essential nutrients, such as the transition metal iron, from host cells. In this study, we show that iron is the most abundant transition metal in C. trachomatis and report the structural and biochemical properties of the iron-recruiting protein YtgA. Knowledge of the high-resolution structure of YtgA will provide a platform for future structure-based antimicrobial design approaches.
A cohort study of Chlamydia trachomatis treatment failure in women: A study protocol
Publisher: Springer Science and Business Media LLC
Date: 17-08-2013
Dysbiosis of the Vaginal Microbiota and Higher Vaginal Kynurenine/Tryptophan Ratio Reveals an Association with Chlamydia trachomatis Genital Infections.
Publisher: Frontiers Media SA
Date: 18-01-2018
Early transcriptional landscapes ofChlamydia trachomatis-infected epithelial cells at single cell resolution
Publisher: Cold Spring Harbor Laboratory
Date: 05-08-2019
DOI: 10.1101/724641
Abstract: Chlamydia are Gram-negative obligate intracellular bacterial pathogens responsible for a variety of disease in humans and animals worldwide. C. trachomatis causes trachoma (infectious blindness) in disadvantaged populations, and is the most common bacterial sexually transmitted infection in humans, causing reproductive tract disease. Antibiotic therapy successfully treats diagnosed chlamydial infections, however asymptomatic infections are common. High-throughput transcriptomic approaches have explored chlamydial gene expression and infected host cell gene expression. However, these were performed on large cell populations, averaging gene expression profiles across all cells s led and potentially obscuring biologically relevant subsets of cells. We generated a pilot dataset, applying single cell RNA-Seq (scRNA-Seq) to C. trachomatis infected and mock-infected epithelial cells to assess the utility of single cell approaches to identify early host cell biomarkers of chlamydial infection. 264 time-matched C. trachomatis -infected and mock-infected HEp-2 cells were collected and subjected to scRNA-Seq. After quality control, 200 cells were retained for analysis. Two distinct clusters distinguished 3-hour cells from 6- and 12-hours. Pseudotime analysis identified a possible infection-specific cellular trajectory for Chlamydia -infected cells, while differential expression analyses found temporal expression of metallothioneins and genes involved with cell cycle regulation, innate immune responses, cytoskeletal components, lipid biosynthesis and cellular stress. Changes to the host cell transcriptome at early times of C. trachomatis infection are readily discernible by scRNA-Seq, supporting the utility of single cell approaches to identify host cell biomarkers of chlamydial infection, and to further deconvolute the complex host response to infection.
Ascension of Chlamydia is moderated by uterine peristalsis and the neutrophil response to infection
Publisher: Public Library of Science (PLoS)
Date: 07-09-2021
DOI: 10.1371/JOURNAL.PCBI.1009365
Abstract: Chlamydia trachomatis is a common sexually transmitted infection that is associated with a range of serious reproductive tract sequelae including in women Pelvic Inflammatory Disease (PID), tubal factor infertility, and ectopic pregnancy. Ascension of the pathogen beyond the cervix and into the upper reproductive tract is thought to be necessary for these pathologies. However, Chlamydia trachomatis does not encode a mechanism for movement on its genome, and so the processes that facilitate ascension have not been elucidated. Here, we evaluate the factors that may influence chlamydial ascension in women. We constructed a mathematical model based on a set of stochastic dynamics to elucidate the moderating factors that might influence ascension of infections in the first month of an infection. In the simulations conducted from the stochastic model, 36% of infections ascended, but only 9% had more than 1000 bacteria ascend. The results of the simulations indicated that infectious load and the peristaltic contractions moderate ascension and are inter-related in impact. Smaller initial loads were much more likely to ascend. Ascension was found to be dependent on the neutrophil response. Overall, our results indicate that infectious load, menstrual cycle timing, and the neutrophil response are critical factors in chlamydial ascension in women.
Delivery of Nitric Oxide for Analysis of the Function of Cytochrome c′
Publisher: Elsevier
Date: 2008
Chlamydia trachomatis Genital Tract Infections: When Host Immune Response and the Microbiome Collide.
Publisher: Elsevier BV
Date: 09-2016
FACTORS ASSOCIATED WITH ANORECTAL CHLAMYDIA OR GONORRHOEA TEST POSITIVITY IN WOMEN - A SYSTEMATIC REVIEW AND META-ANALYSIS
Publisher: BMJ Publishing Group Ltd
Date: 07-2019
The multicopper oxidase of Pseudomonas aeruginosa is a ferroxidase with a central role in iron acquisition
Publisher: Wiley
Date: 09-2002
DOI: 10.1046/J.1365-2958.2002.03132.X
Abstract: Recently it has been observed that multicopper oxidases are present in a number of microbial genomes, raising the question of their function in prokaryotes. Here we describe the analysis of an mco mutant from the opportunistic pathogen Pseudomonas aeruginosa. Unlike wild-type Pseudomonas aeruginosa, the mco mutant was unable to grow aerobically on minimal media with Fe(II) as sole iron source. In contrast, both the wild-type and mutant strain were able to grow either anaerobically via denitrification with Fe(II) or aerobically with Fe(III). Analysis of iron uptake showed that the mco mutant was impaired in Fe(II) uptake but unaffected in Fe(III) uptake. Purification and analysis of the MCO protein confirmed ferroxidase activity. Taken together, these data show that the mco gene encodes a multicopper oxidase that is involved in the oxidation of Fe(II) to Fe(III) subsequent to its acquisition by the cell. In view of the widespread distribution of the mco gene in bacteria, it is suggested that an iron acquisition mechanism involving multicopper oxidases may be an important and hitherto unrecognized feature of bacterial pathogenicity.
Sero-epidemiological assessment of Chlamydia trachomatis infection and sub-fertility in Samoan women.
Publisher: Springer Science and Business Media LLC
Date: 21-04-2016
Design, Synthesis and Biological Evaluation of P2-modified Proline Analogues Targeting the HtrA Serine Protease in Chlamydia
Publisher: American Chemical Society (ACS)
Date: 22-10-2021
DOI: 10.26434/CHEMRXIV-2021-3NM6W
Abstract: High temperature requirement A (HtrA) serine proteases have emerged as a novel class of antibacterial target, which are crucial in protein quality control and are involved in the pathogenesis of a wide array of bacterial infections. Previously, we demonstrated that HtrA in Chlamydia is essential for bacterial survival, replication and virulence. Here, we report a new series of proline (P2)-modified inhibitors of Chlamydia trachomatis HtrA (CtHtrA) developed by proline ring expansion and Cγ-substitutions. The structure-based drug optimization process was guided by molecular modelling and in vitro pharmacological evaluation of inhibitory potency, selectivity and cytotoxicity. Compound 25 from the first-generation 4-substituted proline analogues increased antiCtHtrA potency and selectivity over human neutrophil elastase (HNE) by approximately 6- and 12-fold, respectively, relative to the peptidic lead compound 1. Based on this compound, second-generation substituted proline residues containing 1,2,3-triazole moieties were synthesized by regioselective azide-alkyne click chemistry. Compound 49 demonstrated significantly improved antichlamydial activity in whole cell assays, diminishing the bacterial infectious progeny below the detection limit at the lowest dose tested. Compound 49 resulted in approximately 9- and 22-fold improvement in the inhibitory potency and selectivity relative to 1, respectively. To date, compound 49 is the most potent HtrA inhibitor developed against Chlamydia spp.
Systemic Antibody Response to Chlamydia Trachomatis Infection in Patients Either Infected or Reinfected with Different Chlamydia Serovars
Publisher: Elsevier BV
Date: 07-2017
POST-TREATMENT DETECTION OF AZITHROMYCIN IN HIGH-VAGINAL SWABS USING LIQUID CHROMATOGRAPHY AND TANDEM MASS SPECTROMETRY (LC-MS/MS)
Publisher: BMJ
Date: 07-2013
Oxidoreductase disulfide bond proteins DsbA and DsbB form an active redox pair in Chlamydia trachomatis, a bacterium with disulfide dependent infection and development
Publisher: Public Library of Science (PLoS)
Date: 19-09-2019
A retrospective pilot study to determine whether the reproductive tract microbiota differs between women with a history of infertility and fertile women.
Publisher: Wiley
Date: 26-12-2018
DOI: 10.1111/AJO.12754
Control of dimethylsulfoxide reductase expression in Rhodobacter capsulatus: the role of carbon metabolites and the response regulators DorR and RegA.
Publisher: Microbiology Society
Date: 02-2002
DOI: 10.1099/00221287-148-2-605
Abstract: Regulation of the expression of dimethylsulfoxide (DMSO) reductase was investigated in the purple phototrophic bacterium Rhodobacter capsulatus . Under phototrophic, anaerobic conditions with malate as carbon source, DMSO caused an approximately 150-fold induction of DMSO reductase activity. The response regulator DorR was required for DMSO-dependent induction and also appeared to slightly repress DMSO reductase expression in the absence of substrate. Likewise, when pyruvate replaced malate as carbon source there was an induction of DMSO reductase activity in cells grown at low light intensity (16 W m −2 ) and again this induction was dependent on DorR. The level of DMSO reductase activity in aerobically grown cells was elevated when pyruvate replaced malate as carbon source. One possible explanation for this is that acetyl phosphate, produced from pyruvate, may activate expression of DMSO reductase by direct phosphorylation of DorR, leading to low levels of induction of dor gene expression in the absence of DMSO. A mutant lacking the global response regulator of photosynthesis gene expression, RegA, exhibited high levels of DMSO reductase in the absence of DMSO, when grown phototrophically with malate as carbon source. This suggests that phosphorylated RegA acts as a repressor of dor operon expression under these conditions. It has been proposed elsewhere that RegA-dependent expression is negatively regulated by the cytochrome cbb 3 oxidase. A cco mutant lacking cytochrome cbb 3 exhibited significantly higher levels of Φ[ dorA :: lacZ ] activity in the presence of DMSO compared to wild-type cells and this is consistent with the above model. Pyruvate restored DMSO reductase expression in the regA mutant to the same pattern as found in wild-type cells. These data suggest that R. capsulatus contains a regulator of DMSO respiration that is distinct from DorR and RegA, is activated in the presence of pyruvate, and acts as a negative regulator of DMSO reductase expression.
Koala cathelicidin PhciCath5 has antimicrobial activity, including against Chlamydia pecorum.
Publisher: Public Library of Science (PLoS)
Date: 14-04-2021
DOI: 10.1371/JOURNAL.PONE.0249658
Abstract: Devastating fires in Australia over 2019–20 decimated native fauna and flora, including koalas. The resulting population bottleneck, combined with significant loss of habitat, increases the vulnerability of remaining koala populations to threats which include disease. Chlamydia is one disease which causes significant morbidity and mortality in koalas. The predominant pathogenic species, Chlamydia pecorum , causes severe ocular, urogenital and reproductive tract disease. In marsupials, including the koala, gene expansions of an antimicrobial peptide family known as cathelicidins have enabled protection of immunologically naïve pouch young during early development. We propose that koala cathelicidins are active against Chlamydia and other bacteria and fungi. Here we describe ten koala cathelicidins, five of which contained full length coding sequences that were widely expressed in tissues throughout the body. Focusing on these five, we investigate their antimicrobial activity against two koala C . pecorum isolates from distinct serovars MarsBar and IPTaLE, as well as other bacteria and fungi. One cathelicidin, PhciCath5, inactivated C . pecorum IPTaLE and MarsBar elementary bodies and significantly reduced the number of inclusions compared to the control (p .0001). Despite evidence of cathelicidin expression within tissues known to be infected by Chlamydia , natural PhciCath5 concentrations may be inadequate in vivo to prevent or control C . pecorum infections in koalas. PhciCath5 also displayed antimicrobial activity against fungi and Gram negative and positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Electrostatic interactions likely drive PhciCath5 adherence to the pathogen cell membrane, followed by membrane permeabilisation leading to cell death. Activity against E . coli was reduced in the presence of 10% serum and 20% whole blood. Future modification of the PhciCath5 peptide to enhance activity, including in the presence of serum/blood, may provide a novel solution to Chlamydia infection in koalas and other species.
CtGEM typing: Discrimination of Chlamydia trachomatis ocular and urogenital strains and major evolutionary lineages by high resolution melting analysis of two amplified DNA fragments
Publisher: Public Library of Science (PLoS)
Date: 10-04-2018
Design, synthesis and biological evaluation of P2-modified proline analogues targeting the HtrA serine protease in Chlamydia
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.EJMECH.2021.114064
Abstract: High temperature requirement A (HtrA) serine proteases have emerged as a novel class of antibacterial target, which are crucial in protein quality control and are involved in the pathogenesis of a wide array of bacterial infections. Previously, we demonstrated that HtrA in Chlamydia is essential for bacterial survival, replication and virulence. Here, we report a new series of proline (P2)-modified inhibitors of Chlamydia trachomatis HtrA (CtHtrA) developed by proline ring expansion and Cγ-substitutions. The structure-based drug optimization process was guided by molecular modelling and in vitro pharmacological evaluation of inhibitory potency, selectivity and cytotoxicity. Compound 25 from the first-generation 4-substituted proline analogues increased antiCtHtrA potency and selectivity over human neutrophil elastase (HNE) by approximately 6- and 12-fold, respectively, relative to the peptidic lead compound 1. Based on this compound, second-generation substituted proline residues containing 1,2,3-triazole moieties were synthesized by regioselective azide-alkyne click chemistry. Compound 49 demonstrated significantly improved antichlamydial activity in whole cell assays, diminishing the bacterial infectious progeny below the detection limit at the lowest dose tested. Compound 49 resulted in approximately 9- and 22-fold improvement in the inhibitory potency and selectivity relative to 1, respectively. To date, compound 49 is the most potent HtrA inhibitor developed against Chlamydia spp.
A CASE CONTROL STUDY TO EXAMINE THE CERVICO-VAGINAL MICROBIOTA ASSOCIATED WITH PELVIC INFLAMMATORY DISEASE
Publisher: BMJ Publishing Group Ltd
Date: 07-2019
IgG exacerbates genital chlamydial pathology in females by enhancing pathogenic CD8+ T cell responses
Publisher: Wiley
Date: 13-10-2023
DOI: 10.1111/SJI.13331
Evaluation of a PGP3 ELISA for surveillance of the burden of Chlamydia infection in women from Australia and Samoa.
Publisher: Oxford University Press (OUP)
Date: 04-2019
Abstract: Serological assays can be used to investigate the population burden of infection and potentially sequelae from Chlamydia. We investigated the PGP3 ELISA as a sero-epidemiological tool for infection or sub-fertility in Australian and Samoan women. The PGP3 ELISA absorbance levels were compared between groups of women with infertility, fertile, and current chlamydial infections. In the Australian groups, women with chlamydial tubal factor infertility had significantly higher absorbance levels in the PGP3 ELISA compared to fertile women (P & 0.0001), but not when compared to women with current chlamydial infection (P = 0.44). In the Samoan study, where the prevalence of chlamydial infections is much higher there were significant differences in the PGP3 ELISA absorbance levels between chlamydial sub-fertile women and fertile women (P = 0.003). There was no difference between chlamydial sub-fertile women and women with a current infection (P = 0.829). The results support that the PGP3 assay is effective for sero-epidemiological analysis of burden of infection, but not for evaluation of chlamydial pathological sequelae such as infertility.
High expression of IDO1 and TGF-β1 during recurrence and post infection clearance with Chlamydia trachomatis, are independent of host IFN-γ response.
Publisher: Springer Science and Business Media LLC
Date: 04-03-2019
Characterization of the tail-specific protease (Tsp) from Legionella.
Publisher: Microbiology Research Foundation
Date: 2014
DOI: 10.2323/JGAM.60.95
Abstract: Bacterial tail-specific proteases (Tsps) have been attributed a wide variety of functions including intracellular virulence, cell wall morphology, proteolytic signal cascades and stress response. This study tested the hypothesis that Tsp has a key function for the transmissive form of Legionella pneumophila. A tsp mutant was generated in Legionella pneumophila 130b and the characteristics of this strain and the isogenic wild-type were examined using a range of growth and proteomic analyses. Recombinant Tsp protein was also produced and analyzed. The L. pneumophila tsp mutant showed no defect in growth on rich media or during thermo-osmotic stress conditions. In addition, no defects in cellular morphology were observed when the cells were examined using transmission electron microscopy. Purified recombinant Tsp was found to be an active protease with a narrow substrate range. Proteome analysis using iTRAQ (5% coverage of the proteome) found that, of those proteins detected, only 5 had different levels in the tsp mutant compared to the wild type. ACP (Acyl Carrier Protein), which has a key role for Legionella differentiation to the infectious form, was reduced in the tsp mutant however, tsp(-) was able to infect and replicate inside macrophages to the same extent as the wild type. Combined, these data demonstrate that Tsp is a protease but is not essential for Legionella growth or cell infection. Thus, Tsp may have functional redundancy in Legionella.
Dual RNA-Seq analysis of in vitro infection multiplicity in Chlamydia-infected epithelial cells
Publisher: Cold Spring Harbor Laboratory
Date: 22-10-2020
DOI: 10.1101/2020.10.21.347906
Abstract: Dual RNA-seq experiments examining viral and bacterial pathogens are increasing, but vary considerably in their experimental designs, such as infection rates and RNA depletion methods. Here, we have applied dual RNA-seq to Chlamydia trachomatis infected epithelial cells to examine transcriptomic responses from both organisms. We compared two time points post infection (1 and 24 hours), three multiplicity of infection (MOI) ratios (0.1, 1 and 10) and two RNA depletion methods (rRNA and polyA). Capture of bacterial-specific RNA were greatest when combining rRNA and polyA depletion, and when using a higher MOI. However, under these conditions, host RNA capture was negatively impacted. Although it is tempting to use high infection rates, the implications on host cell survival, the potential reduced length of infection cycles and real world applicability should be considered. This data highlights the delicate nature of balancing host-pathogen RNA capture and will assist future transcriptomic-based studies to achieve more specific and relevant infection-related biological insights.
Expression and characterisation of a major c-type cytochrome encoded by gene kustc0563 from Kuenenia stuttgartiensis as a recombinant protein in Escherichia coli
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/J.PEP.2006.06.026
Abstract: The purification of small quantities of a major small c-type cytochrome from the anammox bacterium Kuenenia stuttgartiensis has recently been reported. In order to characterise this protein further we have expressed the gene encoding this cytochrome in Escherichia coli and have purified the protein to homogeneity. The protein is directed to the E. coli periplasm using its native signal sequence suggesting that it may be translocated via a Sec-type system in K. stuttgartiensis. The cytochrome has the visible spectroscopic properties typical of a low-spin c-type cytochrome, but these spectroscopic features broaden in high salt solutions. The oxidised cytochrome was able to bind the ligands NO and cyanide. A redox potential of +230 mV suggests that the protein is suitable to act as an electron carrier protein that may be involved in the respiratory chain between hydrazine oxidation and the reduction of nitrite. The predicted protein sequence for the cytochrome suggests it to be a predominantly alpha-helical protein, and this is supported by circular dichroism.
Structural and Biochemical Characterization of Chlamydia trachomatis DsbA Reveals a Cysteine-Rich and Weakly Oxidising Oxidoreductase
Publisher: Public Library of Science (PLoS)
Date: 28-12-2016
‘I’m not alone’: outcomes of a faculty-wide initiative for co-creating inclusive science curricula through student–staff partnership
Publisher: Informa UK Limited
Date: 26-10-2021
AZITHROMYCIN VERSUS DOXYCYCLINE FOR THE TREATMENT OF GENITAL CHLAMYDIA INFECTION - A META-ANALYSIS OF RANDOMISED CONTROLLED TRIALS
Publisher: BMJ
Date: 07-2013
CORRELATES OF REPEAT ANORECTAL INFECTIONS AMONG MEN WHO HAVE SEX WITH MEN
Publisher: BMJ
Date: 09-2015
Treatment of rectal chlamydia infection may be more complicated than we originally thought
Publisher: Oxford University Press (OUP)
Date: 04-12-2014
DOI: 10.1093/JAC/DKU493
Abstract: Rectal chlamydia diagnoses have been increasing among MSM and may also rise among women as anal sex rates increase among heterosexuals. However, there is growing concern about treatment for rectal chlamydia with treatment failures of up to 22% being reported. This article addresses factors that may be contributing to treatment failure for rectal chlamydia, including the pharmacokinetic properties of azithromycin and doxycycline in rectal tissue, the ability of chlamydia to transform into a persistent state that is less responsive to antimicrobial therapy, the impact of the rectal microbiome on chlamydia, heterotypic resistance, failure to detect cases of lymphogranuloma venereum and the performance of screening tests. If we are to reduce the burden of genital chlamydia, treatment for rectal chlamydia must be efficacious. This highlights the need for randomized controlled trial evidence comparing azithromycin with doxycycline for the treatment of rectal chlamydia.
Early Transcriptional Landscapes of Chlamydia trachomatis-Infected Epithelial Cells at Single Cell Resolution.
Publisher: Frontiers Media SA
Date: 19-11-2019
Accessibility of the distal heme face, rather than Fe-His bond strength, determines the heme-nitrosyl coordination number of cytochromes c': evidence from spectroscopic studies.
Publisher: American Chemical Society (ACS)
Date: 26-05-2005
DOI: 10.1021/BI050428G
Abstract: The heme coordination chemistry and spectroscopic properties of Rhodobacter capsulatus cytochrome c' (RCCP) have been compared to data from Alcaligenes xylosoxidans (AXCP), with the aim of understanding the basis for their different reactivities with nitric oxide (NO). Whereas ferrous AXCP reacts with NO to form a predominantly five-coordinate heme-nitrosyl complex via a six-coordinate intermediate, RCCP forms an equilibrium mixture of six-coordinate and five-coordinate heme-nitrosyl species in approximately equal proportions. Ferrous RCCP and AXCP both exhibit high Fe-His stretching frequencies (227 and 231 cm(-)(1), respectively), suggesting that factors other than the Fe-His bond strength account for their differences in heme-nitrosyl coordination number. Resonance Raman spectra of ferrous-nitrosyl RCCP confirm the presence of both five-coordinate and six-coordinate heme-NO complexes. The six-coordinate heme-nitrosyl of RCCP exhibits a fairly typical Fe-NO stretching frequency (569 cm(-)(1)), in contrast to the relatively high value (579 cm(-)(1)) of the AXCP six-coordinate heme-nitrosyl intermediate. It is proposed that NO experiences greater steric hindrance in binding to the distal face of AXCP, as compared to RCCP, leading to a more distorted Fe-N-O geometry and an elevated Fe-NO stretching frequency. Evidence that RCCP has a more accessible distal coordination site than in AXCP stems from the fact that ferric RCCP readily forms a heme complex with exogenous imidazole, whereas AXCP does not. A model is proposed in which distal heme-face accessibility, rather than the proximal Fe-His bond strength, determines the heme-nitrosyl coordination number in cytochromes c'.
Copper(II)-bis(thiosemicarbazonato) complexes as anti-chlamydial agents
Publisher: Oxford University Press (OUP)
Date: 24-07-2017
Chlamydial infection of immune cells: altered function and implications for disease.
Publisher: Begell House
Date: 2009
DOI: 10.1615/CRITREVIMMUNOL.V29.I4.10
Abstract: Chlamydia trachomatis is an obligate intracellular bacterial pathogen that infects the genital and ocular mucosa of humans, causing infections that can lead to pelvic inflammatory disease, infertility, and blinding trachoma. C. pneumoniae is a respiratory pathogen that is the cause of 12-15% of community-acquired pneumonia. Both chlamydial species were believed to be restricted to the epithelia of the genital, ocular, and respiratory mucosa however, increasing evidence suggests that both these pathogens can be isolated from peripheral blood of both healthy in iduals and patients with inflammatory conditions such as coronary artery disease and asthma. Chlamydia can also be isolated from brain tissues of patients with degenerative neurological disorders such as Alzheimer's disease and multiple sclerosis, and also from certain lymphomas. An increasing number of in vitro studies suggest that some chlamydial species can infect immune cells, at least at low levels. These infections may alter immune cell function in a way that promotes chlamydial persistence in the host and contributes to the progression of several chronic inflammatory diseases. In this paper, we review the evidence for the growth of Chlamydia in immune cells, particularly monocytes/macrophages and dendritic cells, and describe how infection may affect the function of these cells.
Advancing the public health applications of Chlamydia trachomatis serology.
Publisher: Elsevier BV
Date: 12-2018
Functional analysis of the multi-copper oxidase from Legionella pneumophila
Publisher: Elsevier BV
Date: 04-2008
DOI: 10.1016/J.MICINF.2008.01.011
Abstract: Multicopper oxidases have been described to have functions in copper tolerance, manganese oxidation, and iron oxidation in a range of bacteria. The putative cytoplasmic membrane multicopper oxidase from Legionella pneumophila was investigated. The mcoL gene was found to be critical for aerobic extracellular growth under either iron-limiting conditions or in the presence of ferrous Fe(II) iron, as a sole source of this essential metal. The mcoL mutants showed minor growth defects when grown in the presence of Fe(III) as the iron source. In contrast, intracellular growth and survival was not affected by the absence of the mcoL gene regardless of available iron concentration. The evidence presented here could indicate a possible role for mcoL in prevention of the toxic effects of ferrous iron during aerobic conditions. However, a function in high-affinity acquisition of iron could also be possible given the inability of the McoL mutants to grow aerobically under iron-limiting conditions.
Lipid-modified azurin of Neisseria meningitidis is a copper protein localized on the outer membrane surface and not regulated by FNR.
Publisher: Springer Science and Business Media LLC
Date: 10-02-2015
DOI: 10.1007/S10482-015-0400-Z
Abstract: The laz gene of Neisseria meningitidis is predicted to encode a lipid-modified azurin (Laz). Laz is very similar to azurin, a periplasmic protein, which belongs to the copper-containing proteins in the cupredoxin superfamily. In other bacteria, azurin is an electron donor to nitrite reductase, an important enzyme in the denitrifying process. It is not known whether Laz could function as an electron transfer protein in this important pathogen. Laz protein was heterologously expressed in Escherichia coli and purified. Electrospray mass spectrometry indicated that the Laz protein contains one copper ion. Laz was shown to be redox-active in the presence of its redox center copper ion. When oxidized, Laz exhibits an intense blue colour and absorbs visible light around 626 nm. The absorption is lost when exposed to diethyldithiocarbamate, a copper chelating agent. Polyclonal antibodies were raised against purified Laz for detecting expression of Laz under different growth conditions and to determine the orientation of Laz on the outer membrane. The expression of Laz under microaerobic and microaerobic denitrifying conditions was slightly higher than that under aerobic conditions. However, the expression of Laz was similar between the wild type strain and an fnr mutant, suggesting that Fumarate/Nitrate reduction regulator (FNR) does not regulate the expression of Laz despite the presence of a partial FNR box upstream of the laz gene. We propose that some Laz protein is exposed on the outer membrane surface of N. meningitidis as the αLaz antibodies can increase killing by complement in a capsule deficient N. meningitidis strain, in a dose-dependent fashion.
Repeat infections with chlamydia in women may be more transcriptionally active with lower responses from some immune genes.
Publisher: Frontiers Media SA
Date: 10-10-2022
DOI: 10.3389/FPUBH.2022.1012835
Abstract: Chlamydia trachomatis , the most common bacterial sexually transmitted infection worldwide, is responsible for considerable health burden due to its significant sequelae. There are growing concerns about chlamydial treatment and management due to widely documented increasing burden of repeat infections. In the current study, a cohort study design of 305 women with urogenital chlamydial infections demonstrated that 11.8% of women experienced repeat infections after treatment with azithromycin. The chlamydial DNA load measured by quantitative PCR was higher in women who experienced a repeat infection ( p = 0.0097) and repeat infection was associated with sexual contact. There was no genomic or phenotypic evidence of azithromycin resistance within the chlamydial isolates. During repeat infection, or repeat positive tests during follow up, vaginal chlamydial gene expression ( ompA, euo, omcB, htrA, trpAB ) was markedly higher compared to baseline, and two of the selected immune genes analyzed had significantly lower expression at the time of repeat infection. Overall, there are two implications of these results. The results could be generalized to all recent infections, or repeat positive events, and indicate that chlamydial infections are have higher transcriptional activity of select genes early in the infection in women. Alternatively, after azithromycin treatment, repeat infections of Chlamydia may be more transcriptionally active at certain genes, and there may be post-treatment immunological alterations that interplay into repeat exposures establishing an active infection. The potential that recent infections may involve a higher level of activity from the organism may have implications for management by more regular testing of the most at risk women to reduce the risk of sequelae.
Chromatin accessibility dynamics of Chlamydia-infected epithelial cells
Publisher: Springer Science and Business Media LLC
Date: 27-10-2020
DOI: 10.1186/S13072-020-00368-2
Abstract: Chlamydia are Gram-negative, obligate intracellular bacterial pathogens responsible for a broad spectrum of human and animal diseases. In humans, Chlamydia trachomatis is the most prevalent bacterial sexually transmitted infection worldwide and is the causative agent of trachoma (infectious blindness) in disadvantaged populations. Over the course of its developmental cycle, Chlamydia extensively remodels its intracellular niche and parasitises the host cell for nutrients, with substantial resulting changes to the host cell transcriptome and proteome. However, little information is available on the impact of chlamydial infection on the host cell epigenome and global gene regulation. Regions of open eukaryotic chromatin correspond to nucleosome-depleted regions, which in turn are associated with regulatory functions and transcription factor binding. We applied formaldehyde-assisted isolation of regulatory elements enrichment followed by sequencing (FAIRE-Seq) to generate temporal chromatin maps of C. trachomatis -infected human epithelial cells in vitro over the chlamydial developmental cycle. We detected both conserved and distinct temporal changes to genome-wide chromatin accessibility associated with C. trachomatis infection. The observed differentially accessible chromatin regions include temporally-enriched sets of transcription factors, which may help shape the host cell response to infection. These regions and motifs were linked to genomic features and genes associated with immune responses, re-direction of host cell nutrients, intracellular signalling, cell–cell adhesion, extracellular matrix, metabolism and apoptosis. This work provides another perspective to the complex response to chlamydial infection, and will inform further studies of transcriptional regulation and the epigenome in Chlamydia -infected human cells and tissues.
Evaluation of a biosecurity survey approach for contamination by Chlamydia pecorum in koala rehabilitation, field capture, and captive settings.
Publisher: PeerJ
Date: 15-08-2023
DOI: 10.7717/PEERJ.15842
The blubber adipocyte index: A nondestructive biomarker of adiposity in humpback whales (Megaptera novaeangliae)
Publisher: Wiley
Date: 04-06-2017
DOI: 10.1002/ECE3.2913
Sortilin is associated with the chlamydial inclusion and is modulated during infection
Publisher: The Company of Biologists
Date: 09-03-2016
DOI: 10.1242/BIO.016485
Abstract: Chlamydia species are obligate intracellular pathogens that have a major impact on human health. The pathogen replicates within an intracellular niche called an inclusion and is thought to rely heavily on host-derived proteins and lipids, including ceramide. Sortilin is a transmembrane receptor implicated in the trafficking of acid sphingomyelinase, which is responsible for catalysing the breakdown of sphingomyelin to ceramide. In this study, we examined the role of sortilin in Chlamydia trachomatis L2 development. Western immunoblotting and immunocytochemistry analysis revealed that endogenous sortilin is not only associated with the inclusion, but that protein levels increase in infected cells. RNAi-mediated depletion of sortilin, however, had no detectable impact on ceramide delivery to the inclusion or the production of infectious progeny. This study demonstrates that whilst Chlamydia redirects sortilin trafficking to the chlamydial inclusion, RNAi knockdown of sortilin expression is insufficient to determine if this pathway is requisite for the development of the pathogen.
Expression of common biomarkers in Antarctic krill (Euphausia superba) exposed to an organochlorine contaminant
Publisher: Springer Science and Business Media LLC
Date: 19-09-2018
Fresh faces and new approaches at Pathogens and Disease.
Publisher: Oxford University Press (OUP)
Date: 02-2019
Apoptosis is induced in Chlamydia trachomatis-infected HEp-2 cells by the addition of a combination innate immune activation compounds and the inhibitor wedelolactone.
Publisher: Wiley
Date: 27-12-2011
DOI: 10.1111/J.1600-0897.2010.00936.X
Abstract: Innate immune activation of human cells, for some intracellular pathogens, is advantageous for vacuole morphology and pathogenic viability. It is unknown whether innate immune activation is advantageous to Chlamydia trachomatis viability. Innate immune activation of HEp-2 cells during Chlamydia infection was conducted using lipopolysaccharide (LPS), polyI:C, and wedelolactone (innate immune inhibitor) to investigate the impact of these conditions on viability of Chlamydia. The addition of LPS and polyI:C to stimulate activation of the two distinct innate immune pathways (nuclear factor kappa beta and interferon regulatory factor) had no impact on the viability of Chlamydia. However, when compounds targeting either pathway were added in combination with the specific innate immune inhibitor (wedelolactone) a major impact on Chlamydia viability was observed. This impact was found to be due to the induction of apoptosis of the HEp-2 cells under these conditions. This is the first time that induction of apoptosis has been reported in C. trachomatis-infected cells when treated with a combination of innate immune activators and wedelolactone.
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University Of York
Location: United Kingdom of Great Britain and Northern Ireland
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