ORCID Profile
0000-0003-0161-2204
Current Organisation
Griffith University
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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)
Invertebrate Biology | Microbial Ecology | Genetics Not Elsewhere Classified | Bacteriology | Microbiology | Virology | Genetics | Ecology And Evolution Not Elsewhere Classified | Zoology |
ANZSRC Socio-Economic Objective (SEO)
Biological sciences | Disease distribution and transmission | Control of pests and exotic species | Control of pests and exotic species
Related Links
Publications
Models and Nomenclature for Cytoplasmic Incompatibility: Caution over Premature Conclusions – A Response to Beckmann et al.
Publisher: Elsevier BV
Date: 06-2019
Insect Symbiosis, Volume 2
Publisher: CRC Press
Date: 23-06-2006
Genomic evolution of the pathogenic Wolbachia strain, wMelPop
Publisher: Oxford University Press (OUP)
Date: 11-2013
DOI: 10.1093/GBE/EVT169
Biosensor Technologies for Early Detection and Quantification of Plant Pathogens
Publisher: Frontiers Media SA
Date: 02-06-2021
DOI: 10.3389/FCHEM.2021.636245
Abstract: Plant pathogens are a major reason of reduced crop productivity and may lead to a shortage of food for both human and animal consumption. Although chemical control remains the main method to reduce foliar fungal disease incidence, frequent use can lead to loss of susceptibility in the fungal population. Furthermore, over-spraying can cause environmental contamination and poses a heavy financial burden on growers. To prevent or control disease epidemics, it is important for growers to be able to detect causal pathogen accurately, sensitively, and rapidly, so that the best practice disease management strategies can be chosen and enacted. To reach this goal, many culture-dependent, biochemical, and molecular methods have been developed for plant pathogen detection. However, these methods lack accuracy, specificity, reliability, and rapidity, and they are generally not suitable for in-situ analysis. Accordingly, there is strong interest in developing biosensing systems for early and accurate pathogen detection. There is also great scope to translate innovative nanoparticle-based biosensor approaches developed initially for human disease diagnostics for early detection of plant disease-causing pathogens. In this review, we compare conventional methods used in plant disease diagnostics with new sensing technologies in particular with deeper focus on electrochemical and optical biosensors that may be applied for plant pathogen detection and management. In addition, we discuss challenges facing biosensors and new capability the technology provides to informing disease management strategies.
Wolbachia genomes: Insights into an intracellular lifestyle
Publisher: Elsevier BV
Date: 07-2005
DOI: 10.1016/J.CUB.2005.06.029
Abstract: The genome sequence of the Wolbachia endosymbiont that infects the nematode Brugia malayi has recently been determined together with three partial Wolbachia genomes from different Drosophila species. These data along with the previously published Wolbachia genome from Drosophila melanogaster provide new insights into how this endosymbiont has managed to become so successful.
P2X7 receptor signaling during adult hippocampal neurogenesis
Publisher: Medknow
Date: 2019
P2X7 Receptors Regulate Phagocytosis and Proliferation in Adult Hippocampal and SVZ Neural Progenitor Cells: Implications for Inflammation in Neurogenesis
Publisher: Oxford University Press (OUP)
Date: 17-09-2018
DOI: 10.1002/STEM.2894
Abstract: Identifying the signaling mechanisms that regulate adult neurogenesis is essential to understanding how the brain may respond to neuro-inflammatory events. P2X7 receptors can regulate pro-inflammatory responses, and in addition to their role as cation channels they can trigger cell death and mediate phagocytosis. How P2X7 receptors may regulate adult neurogenesis is currently unclear. Here, neural progenitor cells (NPCs) derived from adult murine hippoc al subgranular (SGZ) and cerebral subventricular (SVZ) zones were utilized to characterize the roles of P2X7 in adult neurogenesis, and assess the effects of high extracellular ATP, characteristic of inflammation, on NPCs. Immunocytochemistry found NPCs in vivo and in vitro expressed P2X7, and the activity of P2X7 in culture was demonstrated using calcium influx and pore formation assays. Live cell and confocal microscopy, in conjunction with flow cytometry, revealed P2X7+ NPCs were able to phagocytose fluorescent beads, and this was inhibited by ATP, indicative of P2X7 involvement. Furthermore, P2X7 receptors were activated with ATP or BzATP, and 5-ethynyl-2′-deoxyuridine (EdU) used to observe a dose-dependent decrease in NPC proliferation. A role for P2X7 in decreased NPC proliferation was confirmed using chemical inhibition and NPCs from P2X7−/− mice. Together, these data present three distinct roles for P2X7 during adult neurogenesis, depending on extracellular ATP concentrations: (a) P2X7 receptors can form transmembrane pores leading to cell death, (b) P2X7 receptors can regulate rates of proliferation, likely via calcium signaling, and (c) P2X7 can function as scavenger receptors in the absence of ATP, allowing NPCs to phagocytose apoptotic NPCs during neurogenesis.
Contrasting patterns of virus protection and functional incompatibility genes in two conspecific Wolbachia strains from Drosophila pandora
Publisher: American Society for Microbiology
Date: 03-2018
DOI: 10.1128/AEM.02290-18
Abstract: Wolbachia strains are common endosymbionts in insects, with multiple strains often coexisting in the same species. The coexistence of multiple strains is poorly understood but may rely on Wolbachia organisms having erse phenotypic effects on their hosts. As Wolbachia is increasingly being developed as a tool to control disease transmission and suppress pest populations, it is important to understand the ways in which multiple Wolbachia strains persist in natural populations and how these might then be manipulated. We have therefore investigated viral protection and the molecular basis of cytoplasmic incompatibility in two coexisting Wolbachia strains with contrasting effects on host reproduction.
Quantitative proteomic analyses of molecular mechanisms associated with cytoplasmic incompatibility in drosophila melanogaster induced by wolbachia
Publisher: American Chemical Society (ACS)
Date: 12-08-2015
DOI: 10.1021/ACS.JPROTEOME.5B00191
Abstract: To investigate the molecular mechanisms of cytoplasmic incompatibility (CI) induced by Wolbachia bacteria in Drosophila melanogaster, we applied an isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomic assay to identify differentially expressed proteins extracted from spermathecae and seminal receptacles (SSR) of uninfected females mated with either 1-day-old Wolbachia-uninfected (1T) or infected males (1W) or 5-day-old infected males (5W). In total, 1317 proteins were quantified 83 proteins were identified as having at least a 1.5-fold change in expression when 1W was compared with 1T. Differentially expressed proteins were related to metabolism, immunity, and reproduction. Wolbachia changed the expression of seminal fluid proteins (Sfps). Wolbachia may disrupt the abundance of proteins in SSR by affecting ubiquitin-proteasome-mediated proteolysis. Knocking down two Sfp genes (CG9334 and CG2668) in Wolbachia-free males resulted in significantly lower embryonic hatch rates with a phenotype of chromatin bridges. Wolbachia-infected females may rescue the hatch rates. This suggests that the changed expression of some Sfps may be one of the mechanisms of CI induced by Wolbachia. This study provides a panel of candidate proteins that may be involved in the interaction between Wolbachia and their insect hosts and, through future functional studies, may help to elucidate the underlying mechanisms of Wolbachia-induced CI.
Functional test of the influence of Wolbachia genes on cytoplasmic incompatibility expression in Drosophila melanogaster
Publisher: Wiley
Date: 21-09-2011
DOI: 10.1111/J.1365-2583.2010.01042.X
Abstract: Wolbachia are inherited intracellular bacteria that infect a broad range of invertebrate hosts. They commonly manipulate host reproduction in a variety of ways and thereby favour their invasion into host populations. While the biology of Wolbachia has been extensively studied at the ecological and phenotypic level, little is known about the molecular mechanisms underlying the interaction between Wolbachia and their hosts. Recent comparative genomics studies of Wolbachia strains have revealed putative candidate genes involved in the expression of cytoplasmic incompatibility (CI) in insects. However the functional testing of these genes is hindered by the lack of available genetic tools in Wolbachia. To circumvent this problem we generated transgenic Drosophila lines expressing various Wolbachia CI candidate genes under the control of the GAL4/UAS system in order to evaluate their possible role in Wolbachia-related phenotypes in Drosophila. The expression of a number of these genes in Drosophila melanogaster failed to mimic or alter CI phenotypes across a range of Wolbachia backgrounds or in the absence of Wolbachia.
Evidence and Consequence of a Highly Adapted Clonal Haplotype within the Australian Ascochyta rabiei Population
Publisher: Frontiers Media SA
Date: 16-06-2017
Wolbachia infection may improve learning and memory capacity of Drosophila by altering host gene expression through microRNA
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.IBMB.2018.11.007
Abstract: Wolbachia are endosymbiotic bacteria present in a wide range of invertebrates. Although their dramatic effects on host reproductive biology have been well studied, little is known about the effects of Wolbachia on the learning and memory capacity (LMC) of hosts, despite their distribution in the host nervous system, including brain. In this study, we found that Wolbachia infection significantly enhanced LMC in both Drosophila melanogaster and D. simulans. Expression of LMC-related genes was significantly increased in the head of D. melanogaster infected with the wMel strain, and among these genes, crebA was up-regulated the most. Knockdown of crebA in Wolbachia-infected flies significantly decreased LMC, while overexpression of crebA in Wolbachia-free flies significantly enhanced the LMC of flies. More importantly, a microRNA (miRNA), dme-miR-92b, was identified to be complementary to the 3'UTR of crebA. Wolbachia infection was correlated with reduced expression of dme-miR-92b in D. melanogaster, and dme-miR-92b negatively regulated crebA through binding to its 3'UTR region. Overexpression of dme-miR-92b in Wolbachia-infected flies by microinjection of agomirs caused a significant decrease in crebA expression and LMC, while inhibition of dme-miR-92b in Wolbachia-free flies by microinjection of antagomirs resulted in a significant increase in crebA expression and LMC. These results suggest that Wolbachia may improve LMC in Drosophila by altering host gene expression through a miRNA-target pathway. Our findings help better understand the host-endosymbiont interactions and, in particular, the impact of Wolbachia on cognitive processes in invertebrate hosts.
Survival capabilities of Escherichia coli O26 isolated from cattle and clinical sources in Australia to disinfectants, acids and antimicrobials
Publisher: Springer Science and Business Media LLC
Date: 03-2017
Intensity of Mutualism Breakdown Is Determined by Temperature Not Amplification of Wolbachia Genes
Publisher: Public Library of Science (PLoS)
Date: 23-09-2016
The Caenorhabditis briggsae genome contains active CbmaT1 and Tcb1 transposons
Publisher: Springer Science and Business Media LLC
Date: 09-02-2005
DOI: 10.1007/S00438-005-1110-4
Abstract: The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.
Correction to: Characterization of biofilm-forming capacity and resistance to sanitizers of a range of E.coli O26 pathotypes from clinical cases and cattle in Australia
Publisher: Springer Science and Business Media LLC
Date: 19-06-2018
Insights into Wolbachia biology provided through genomic analysis
Publisher: KARGER
Date: 2007
DOI: 10.1159/000104245
Wolbachia-Mediated Antibacterial Protection and Immune Gene Regulation in Drosophila
Publisher: Public Library of Science (PLoS)
Date: 29-09-2011
Symbiont-mediated protection in insect hosts
Publisher: Elsevier BV
Date: 08-2009
DOI: 10.1016/J.TIM.2009.05.005
Abstract: Microbes influence the ecology and evolution of their hosts in a variety of ways, including the formation of life-long beneficial or detrimental parasitic infections. Understanding the molecular and biochemical events that underpin symbiosis - beneficial or parasitic - has been a long-term goal of molecular symbiosis research. In addition to beneficial symbionts provisioning scarce resources to their hosts, a growing body of evidence shows that bacterial symbionts can protect their hosts from parasitic symbionts and predators. Here, we review recent theoretical predictions and experimental observations of symbiont-mediated protection in insects. We discuss the implications that protection has for the ecology and evolution of host, symbiont and pathogen and describe what is known about the molecular mechanisms that underpin symbiont protection.
Wolbachia and Virus Protection in Insects
Publisher: American Association for the Advancement of Science (AAAS)
Date: 31-10-2008
Abstract: Wolbachia pipientis bacteria are common endosymbionts of insects that are best known for their ability to increase their prevalence in populations by manipulating host reproductive systems. However, there are ex les of Wolbachia that exist in nature that seem to induce no reproductive parasitism trait and yet are able to invade populations. We demonstrate a fitness benefit for Wolbachia-infected insects that may explain this paradox. Drosophila melanogaster flies infected with Wolbachia are less susceptible to mortality induced by a range of RNA viruses. The antiviral protection associated with Wolbachia infection might be exploited in future strategies to reduce transmission of pathogens by insects.
Characterization of biofilm-forming capacity and resistance to sanitizers of a range of E. coli O26 pathotypes from clinical cases and cattle in Australia
Publisher: Springer Science and Business Media LLC
Date: 08-05-2018
Response to: Comment on Rohrscheib et al. 2016 Intensity of mutualism breakdown is determined by temperature not amplification of Wolbachia genes
Publisher: Public Library of Science (PLoS)
Date: 11-09-2017
Solving theWolbachiaParadox: Modeling the Tripartite Interaction between Host,Wolbachia, and a Natural Enemy
Publisher: University of Chicago Press
Date: 09-2011
DOI: 10.1086/661247
Abstract: Wolbachia is one of the most common symbionts of arthropods. Its establishment requires lateral transfer to and successful transmission within novel host species. However, Wolbachia performs poorly when introduced into new host species, and models predict that Wolbachia should seldom be able to establish from low initial frequencies. Recently, various symbionts, including Wolbachia, have been shown to protect their hosts from natural enemies. Hence, Wolbachia invasion may be facilitated by the dynamic interaction between it, its host, and a natural enemy. We model such an interaction whereby Wolbachia induces either complete resistance, partial resistance, or tolerance to a host-specific pathogen and also induces the common manipulation phenotype of cytoplasmic incompatibility (CI). We show that the presence of the pathogen greatly facilitates Wolbachia invasion from rare and widens the parameter space in which "imperfect" Wolbachia strains can invade. Furthermore, positive frequency-dependent selection through CI can drive Wolbachia to very high frequencies, potentially excluding the pathogen. These results may explain a poorly understood aspect of Wolbachia biology: it is widespread, despite performing poorly after transfer to new host species. They also support the intriguing possibility that Wolbachia strains that encode both CI and natural-enemy resistance could potentially rid insects, including human disease vectors, of important pathogens.
Oxidative Stress Correlates with Wolbachia-Mediated Antiviral Protection in Wolbachia-Drosophila Associations
Publisher: American Society for Microbiology
Date: 05-2015
DOI: 10.1128/AEM.03847-14
Abstract: Wolbachia mediates antiviral protection in insect hosts and is being developed as a potential biocontrol agent to reduce the spread of insect-vectored viruses. Definition of the molecular mechanism that generates protection is important for understanding the tripartite interaction between host insect, Wolbachia , and virus. Elevated oxidative stress was previously reported for a mosquito line experimentally infected with Wolbachia , suggesting that oxidative stress is important for Wolbachia -mediated antiviral protection. However, Wolbachia experimentally introduced into mosquitoes impacts a range of host fitness traits, some of which are unrelated to antiviral protection. To explore whether elevated oxidative stress is associated with antiviral protection in Wolbachia -infected insects, we analyzed oxidative stress of five Wolbachia -infected Drosophila lines. In flies infected with protective Wolbachia strains, hydrogen peroxide concentrations were 1.25- to 2-fold higher than those in paired fly lines cured of Wolbachia infection. In contrast, there was no difference in the hydrogen peroxide concentrations in flies infected with nonprotective Wolbachia strains compared to flies cured of Wolbachia infection. Using a Drosophila mutant that produces increased levels of hydrogen peroxide, we investigated whether flies with high levels of endogenous reactive oxygen species had altered responses to virus infection and found that flies with high levels of endogenous hydrogen peroxide were less susceptible to virus-induced mortality. Taken together, these results suggest that elevated oxidative stress correlates with Wolbachia -mediated antiviral protection in natural Drosophila hosts.
Phylogenomics of the reproductive parasite Wolbachia pipientis wMel: A streamlined genome overrun by mobile genetic elements
Publisher: Public Library of Science (PLoS)
Date: 16-03-2004
Inhibition of Shewanella spp. growth by Syzygium australe and Syzygium luehmannii extracts: natural methods for the prevention of fish spoilage
Publisher: Springer Science and Business Media LLC
Date: 22-08-2017
Hsp90 and physiological stress are linked to autonomous transposon mobility and heritable genetic change in nematodes
Publisher: Oxford University Press (OUP)
Date: 12-01-2016
DOI: 10.1093/GBE/EVW284
Antiviral Protection and the Importance of Wolbachia Density and Tissue Tropism in Drosophila simulans
Publisher: American Society for Microbiology
Date: 10-2012
DOI: 10.1128/AEM.01727-12
Abstract: Wolbachia , a maternally transmitted endosymbiont of insects, is increasingly being seen as an effective biological control agent that can interfere with transmission of pathogens, including dengue virus. However, the mechanism of antiviral protection is not well understood. The density and distribution of Wolbachia in host tissues have been implicated as contributing factors by previous studies with both mosquitoes and flies. Drosophila flies infected with five erse strains of Wolbachia were screened for the ability to mediate antiviral protection. The three protective Wolbachia strains were more closely related and occurred at a higher density within whole flies than the two nonprotective Wolbachia strains. In this study, to further investigate the relationship between whole-fly Wolbachia density and the ability to mediate antiviral protection, tetracycline was used to decrease the abundance of the high-density, protective Wolbachia strain w Au prior to viral challenge. Antiviral protection was lost when the density of the protective Wolbachia strain was decreased to an abundance similar to that of nonprotective Wolbachia strains. We determined the Wolbachia density and distribution in tissues of the same five fly- Wolbachia combinations as used previously. The Wolbachia density within the head, gut, and Malpighian tubules correlated with the ability to mediate antiviral protection. These findings may facilitate the development of Wolbachia biological control strategies and help to predict host- Wolbachia pairings that may interfere with virus-induced pathology.
maT—A Clade of Transposons Intermediate Between mariner and Tc1
Publisher: Oxford University Press (OUP)
Date: 12-2002
DOI: 10.1093/OXFORDJOURNALS.MOLBEV.A004035
Abstract: A group of transposons, named maT, with characteristics intermediate between mariner and Tc1 transposons, is described. Two defective genomic copies of MdmaT from the housefly Musca domestica, with 85% identity, were found flanking and imbedded in the MdalphaE7 esterase gene involved in organophosphate insecticide resistance. Two cDNA clones, with 99% identity to each other and 72%-89% identity to the genomic copies were also obtained, but both represented truncated versions of the putative open reading frame. A third incomplete genomic copy of MdmaT was also identified upstream of the putative M. domestica period gene. The MdmaT sequences showed high identity to the transposable element Bmmar1 from the silkworm moth, Bombyx mori, and to previously unidentified sequences in the genome of Caenorhabditis elegans. A total of 16 copies of full-length maT sequences were identified in the C. elegans genome, representing three variants of the transposon, with 34%-100% identity amongst them. Twelve of the copies, named CemaT1, were virtually identical, with eight of them encoding a putative full length, intact transposase. Secondary structure predictions and phylogenetic analyses confirm that maT elements belong to the mariner-Tc1 superfamily of transposons, but their intermediate sequence and predicted structural characteristics suggest that they belong to a unique clade, distinct from either mariner-like or Tc1-like elements.
CemaT1 is an active transposon within the Caenorhabditis elegans genome
Publisher: Elsevier BV
Date: 08-2004
Evidence for Metabolic Provisioning by a Common Invertebrate Endosymbiont, Wolbachia pipientis, during Periods of Nutritional Stress
Publisher: Public Library of Science (PLoS)
Date: 03-04-2009
Identification of Novel Non-autonomous CemaT Transposable Elements and Evidence of their Mobility within the C. elegans Genome
Publisher: Springer Science and Business Media LLC
Date: 11-2005
DOI: 10.1007/S10709-005-8548-5
Abstract: We describe here two new transposable elements, CemaT4 and CemaT5, that were identified within the sequenced genome of Caenorhabditis elegans using homology based searches. Five variants of CemaT4 were found, all non-autonomous and sharing 26 bp inverted terminal repeats (ITRs) and segments (152-367 bp) of sequence with similarity to the CemaT1 transposon of C. elegans. Sixteen copies of a short, 30 bp repetitive sequence, comprised entirely of an inverted repeat of the first 15 bp of CemaT4's ITR, were also found, each flanked by TA dinucleotide duplications, which are hallmarks of target site duplications of mariner-Tc transposon transpositions. The CemaT5 transposable element had no similarity to maT elements, except for sharing identical ITR sequences with CemaT3. We provide evidence that CemaT5 and CemaT3 are capable of excising from the C. elegans genome, despite neither transposon being capable of encoding a functional transposase enzyme. Presumably, these two transposons are cross-mobilised by an autonomous transposon that recognises their shared ITRs. The excisions of these and other non-autonomous elements may provide opportunities for abortive gap repair to create internal deletions and/or insert novel sequence within these transposons. The influence of non-autonomous element mobility and structural ersity on genome variation is discussed.
Real-time Live-cell Flow Cytometry to Investigate Calcium Influx, Pore Formation, and Phagocytosis by P2X7 Receptors in Adult Neural Progenitor Cells
Publisher: MyJove Corporation
Date: 03-04-2019
DOI: 10.3791/59313
Abstract: Live-cell flow cytometry is increasingly used among cell biologists to quantify biological processes in a living cell culture. This protocol describes a method whereby live-cell flow cytometry is extended upon to analyze the multiple functions of P2X7 receptor activation in real-time. Using a time module installed on a flow cytometer, live-cell functionality can be assessed and plotted over a given time period to explore the kinetics of calcium influx, transmembrane pore formation, and phagocytosis. This simple method is advantageous as all three canonical functions of the P2X7 receptor can be assessed using one machine, and the gathered data plotted over time provides information on the entire live-cell population rather than single-cell recordings often obtained using technically challenging patch-cl methods. Calcium influx experiments use a calcium indicator dye, while P2X7 pore formation assays rely on ethidium bromide being allowed to pass through the transmembrane pore formed upon high agonist concentrations. Yellow-green (YG) latex beads are utilized to measure phagocytosis. Specific agonists and antagonists are applied to investigate the effects of P2X7 receptor activity. In idually, these methods can be modified to provide quantitative data on any number of calcium channels and purinergic and scavenger receptors. Taken together, they highlight how the use of real-time live-cell flow cytometry is a rapid, cost-effective, reproducible, and quantifiable method to investigate P2X7 receptor function.
Biotechnological production of hyaluronic acid: a mini review
Publisher: Springer Science and Business Media LLC
Date: 15-02-2016
The development of a real-time quantitative polymerase chain reaction (Qpcr) method for the detection of staphylococcus aureus in peripherally inserted central catheter (picc) colonisation
Publisher: Cambridge Media
Date: 11-11-2019
Diversifying selection and host adaptation in two endosymbiont genomes
Publisher: Springer Science and Business Media LLC
Date: 30-04-2007
Abstract: The endosymbiont Wolbachia pipientis infects a broad range of arthropod and filarial nematode hosts. These erse associations form an attractive model for understanding host:symbiont coevolution. Wolbachia 's ubiquity and ability to dramatically alter host reproductive biology also form the foundation of research strategies aimed at controlling insect pests and vector-borne disease. The Wolbachia strains that infect nematodes are phylogenetically distinct, strictly vertically transmitted, and required by their hosts for growth and reproduction. Insects in contrast form more fluid associations with Wolbachia . In these taxa, host populations are most often polymorphic for infection, horizontal transmission occurs between distantly related hosts, and direct fitness effects on hosts are mild. Despite extensive interest in the Wolbachia system for many years, relatively little is known about the molecular mechanisms that mediate its varied interactions with different hosts. We have compared the genomes of the Wolbachia that infect Drosophila melanogaster , w Mel and the nematode Brugia malayi , w Bm to that of an outgroup Anaplasma marginale to identify genes that have experienced ersifying selection in the Wolbachia lineages. The goal of the study was to identify likely molecular mechanisms of the symbiosis and to understand the nature of the erse association across different hosts. The prevalence of selection was far greater in w Mel than w Bm. Genes contributing to DNA metabolism, cofactor biosynthesis, and secretion were positively selected in both lineages. In w Mel there was a greater emphasis on DNA repair, cell ision, protein stability, and cell envelope synthesis. Secretion pathways and outer surface protein encoding genes are highly affected by selection in keeping with host:parasite theory. If evidence of selection on various cofactor molecules reflects possible provisioning, then both insect as well as nematode Wolbachia may be providing substances to hosts. Selection on cell envelope synthesis, DNA replication and repair machinery, heat shock, and two component switching suggest strategies insect Wolbachia may employ to cope with erse host and intra-host environments.
Establishing historical sample data is essential for identification of unaccounted Australian soldiers from WWI, WWII, and the Korean War
Publisher: Informa UK Limited
Date: 10-06-2020
The microbial biofilm composition on peripherally inserted central catheters: A comparison of polyurethane and hydrophobic catheters collected from paediatric patients
Publisher: SAGE Publications
Date: 22-06-2020
Abstract: Peripherally inserted central catheters are susceptible to microbial colonisation and subsequent biofilm formation, leading to central line–associated bloodstream infection, a serious peripherally inserted central catheter–related complication. Next-generation peripherally inserted central catheter biomaterials, such as hydrophobic materials (e.g. Endexo ® ), may reduce microbial biofilm formation or attachment, consequently reducing the potential for central line–associated bloodstream infection. Within a randomised controlled trial, culture-dependent and culture-independent methods were used to determine if the biomaterials used in traditional polyurethane peripherally inserted central catheters and hydrophobic peripherally inserted central catheters impacted microbial biofilm composition. This study also explored the impact of other clinical characteristics including central line–associated bloodstream infection, antibiotic therapy and dwell time on the microbial biofilm composition of peripherally inserted central catheters. From a total of 32 patients, one peripherally inserted central catheter was determined to be colonised with Staphylococcus aureus, and on further analysis, the patient was diagnosed with central line–associated bloodstream infection. All peripherally inserted central catheters ( n = 17 polyurethane vs n = 15 hydrophobic) were populated with complex microbial communities, including peripherally inserted central catheters considered non-colonised. The two main microbial communities observed included Staphylococcus spp., dominant on the colonised peripherally inserted central catheter, and Enterococcus, dominant on non-colonised peripherally inserted central catheters. Both the peripherally inserted central catheter biomaterial design and antibiotic therapy had no significant impact on microbial communities. However, the ersity of microbial communities significantly decreased with dwell time. More erse pathogens were present on the colonised peripherally inserted central catheter collected from the patient with central line–associated bloodstream infection. Microbial biofilm composition did not appear to be affected by the design of peripherally inserted central catheter biomaterials or antibiotic therapy. However, the ersity of the microbial communities appeared to decrease with dwell time.
Draft genome sequence of the male-killing Wolbachia strain wBol1 reveals recent horizontal gene transfers from diverse sources
Publisher: Springer Science and Business Media LLC
Date: 2013
Impact of ERK activation on fly survival and Wolbachia-mediated protection during virus infection
Publisher: Microbiology Society
Date: 06-2016
DOI: 10.1099/JGV.0.000456
Abstract: Elevated levels of reactive oxygen species (ROS) provide protection against virus-induced mortality in Drosophila. In addition to contributing to oxidative stress, ROS are known to activate a number of signalling pathways including the extracellular signal-regulated kinases (ERK) signalling cascade. It was recently shown that ERK signalling is important for resistance against viral replication and invasion in cultured Drosophila cells and the gut epithelium of adult flies. Here, using a Drosophila loss-of-function ERK (rolled) mutant we demonstrated that ERK is important for fly survival during virus infection. ERK mutant flies subjected to Drosophila C virus (DCV) oral and systemic infection were more susceptible to virus-induced mortality as compared with wild-type flies. We have demonstrated experimentally that ERK activation is important for fly survival during oral and systemic virus infection. Given that elevated ROS correlates with Wolbachia-mediated antiviral protection, we also investigated the involvement of ERK in antiviral protection in flies infected by Wolbachia. The results indicate that ERK activation is increased in the presence of Wolbachia but this does not appear to influence Wolbachia-mediated antiviral protection, at least during systemic infection.
The Metabolic Response to Infection With Wolbachia Implicates the Insulin/Insulin-Like-Growth Factor and Hypoxia Signaling Pathways in Drosophila melanogaster
Publisher: Frontiers Media SA
Date: 22-03-2021
Abstract: The endosymbiotic bacteria, Wolbachia , are best known for their ability to manipulate insect-host reproduction systems that enhance their vertical transmission within host populations. Increasingly, Wolbachia have been shown to depend on their hosts' metabolism for survival and in turn provision metabolites to their host. Wolbachia depends completely on the host for iron and as such iron has been speculated to be a fundamental aspect of Wolbachia -host interplay. However, the mechanisms by which dietary iron levels, Wolbachia , and its host interact remain to be elucidated. To understand the metabolic dependence of Wolbachia on its host, the possibility of metabolic provisioning and extraction, and the interplay with available dietary iron, we have used NMR-based metabolomics and compared metabolite profiles of Wolbachia -infected and uninfected Drosophila melanogaster flies raised on varying levels of dietary iron. We observed marked metabolite differences in the affected metabolite pathways between Wolbachia -infected and uninfected Drosophila , which were dependent on the dietary iron levels. Excess iron led to lipid accumulation, whereas iron deficiency led to changes in carbohydrate levels. This represents a major metabolic shift triggered by alterations in iron levels. Lipids, some amino acids, carboxylic acids, and nucleosides were the major metabolites altered by infection. The metabolic response to infection showed a reprogramming of the mitochondrial metabolism in the host. Based on these observations, we developed a physiological model which postulates that the host's insulin/insulin-like-growth factor pathway is depressed and the hypoxia signaling pathway is activated upon Wolbachia infection. This reprogramming leads to predominantly non-oxidative metabolism in the host, whereas Wolbachia maintains oxidative metabolism. Our data also support earlier predictions of the extraction of alanine from the host while provisioning riboflavin and ATP to the host.
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