ORCID Profile
0000-0003-3955-3406
Current Organisation
University of South Australia
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Wiley
Date: 15-03-2011
DOI: 10.1016/J.FEBSLET.2011.03.022
Abstract: The Saccharomyces cerevisiae MEF2 gene is a mitochondrial protein translation factor. Formerly believed to catalyze peptide elongation, evidence now suggests its involvement in ribosome recycling. This study confirms the role of the MEF2 gene for cell respiration and further uncovers a slow growth phenotype and reduced chronological lifespan. Furthermore, in comparison with cytoplasmic ρ(0) strains, mef2Δ strains have a marked reduction of the inner mitochondrial membrane potential and mitochondria show a tendency to aggregate, suggesting an additional role for the MEF2 gene in maintenance of mitochondrial health, a role that may also be shared by other mitochondrial protein synthesis factors.
Publisher: Informa UK Limited
Date: 15-06-2022
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.FOODCHEM.2018.02.115
Abstract: Despite numerous studies, the identity of the compounds that are responsible for 'stone fruit' aroma in wine has not been conclusively established. This study focussed on wine varieties that often display peach and apricot characters, such as Chardonnay, Viognier and botrytis-affected sweet Semillon wines. Wines with high and low 'stone fruit' aroma were evaluated by gas chromatography-olfactometry-mass spectrometry (GC-O-MS) using extracts representative of the aroma of the wine in a glass. No aroma-active zone was described as 'stone fruit' aroma across all three wine varietals. However, for the in idual varieties, terpenes, such as linalool and geraniol, in the Viognier wines, several esters in the Chardonnay wines, and γ-nonalactone in the botrytis Semillon were associated with 'stone fruit' aroma. Notably, this is the first study assessing the aroma profile of Viognier wine by GC-O. In addition, an extension study of Viognier grape monoterpene profiles clarified its classification as an aromatic variety.
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.BMCL.2017.01.042
Abstract: Drug efflux pumps confer multidrug resistance to dangerous pathogens which makes these pumps important drug targets. We have synthesised a novel series of compounds based on a 2-naphthamide pharmacore aimed at inhibiting the efflux pumps from Gram-negative bacteria. The archeatypical transporter AcrB from Escherichia coli was used as model efflux pump as AcrB is widely conserved throughout Gram-negative organisms. The compounds were tested for their antibacterial action, ability to potentiate the action of antibiotics and for their ability to inhibit Nile Red efflux by AcrB. None of the compounds were antimicrobial against E. coli wild type cells. Most of the compounds were able to inhibit Nile Red efflux indicating that they are substrates of the AcrB efflux pump. Three compounds were able to synergise with antibiotics and reverse resistance in the resistant phenotype. Compound A3, 4-(isopentyloxy)-2-naphthamide, reduced the MICs of erythromycin and chlor henicol to the MIC levels of the drug sensitive strain that lacks an efflux pump. A3 had no effect on the MIC of the non-substrate rif icin indicating that this compound acts specifically through the AcrB efflux pump. A3 also does not act through non-specific mechanisms such as outer membrane or inner membrane permeabilisation and is not cytotoxic against mammalian cell lines. Therefore, we have designed and synthesised a novel chemical compound with great potential to further optimisation as inhibitor of drug efflux pumps.
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.FOODCHEM.2018.02.094
Abstract: (Z)-6-Dodeceno-γ-lactone is a potent aroma compound that has been little studied and its prevalence in wines is unknown. An efficient stable isotope dilution assay was developed using a simple, direct immersion solid-phase microextraction and gas chromatography-tandem mass spectrometry method suitable for routine use with a low ng/L limit of quantitation. Using this method, 99 out of 104 young white wines analysed were found to contain detectable (Z)-6-dodeceno-γ-lactone. The highest concentrations were found in Riesling and Viognier wines. (Z)-6-Dodeceno-γ-lactone was found to have an aroma detection threshold of 700 ng/L in a neutral white wine. This study established that (Z)-6-dodeceno-γ-lactone is widely present in Australia's most popular white wine varieties, but generally at concentrations below its aroma detection threshold.
Publisher: American Chemical Society (ACS)
Date: 21-10-2020
Abstract: Glycosides are sugar conjugates of aroma compounds that are found in many fruits and vegetables, and while glycosides are non-volatile, they can release flavor during eating, through enzyme hydrolysis from oral microbiota. Recently, a range of sensory phenotypes for glucoside perception have been observed, reflecting interin idual variation in response to precursors of floral and smoky flavors, geranyl glucoside and guaiacyl glucoside. To understand this variation and investigate the role of oral microbiota on
Publisher: Elsevier BV
Date: 2018
DOI: 10.1016/J.EJMECH.2017.11.102
Abstract: A novel series of 4-substituted 2-naphthamide derivatives were designed, synthesized and evaluated for their biological activity. In particular, the ability of the compounds to potentiate the action of antibiotics, to inhibit Nile Red efflux and to target AcrB specifically was investigated. The results indicated that most of the 4-substituted 2-naphthamide derivatives were able to synergize with the antibiotics tested, and inhibit Nile Red efflux by AcrB in the resistant phenotype. Subsequent exclusion of compounds with off target effects such as outer- or inner membrane permeabilization identified compounds 7c, 7g, 12c, 12i and 13g as efflux pump inhibitors (EPIs). Particularly, compounds 7c, 7g and 12i were found to be the most potent EPIs, which synergized with the two substrates tested at lower concentrations than that of parent A3, demonstrating an improvement in potency as compared to A3. Additionally, when the outer membrane of E. coli was permeabilized, compound 12c displayed a huge increase in efficacy and was able to synergize with erythromycin at a concentration that was 16 times lower than that of the parent A3. Hence we were able to design and synthesize compounds that displayed significant increase in efficacy as EPIs against AcrB.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Public Library of Science (PLoS)
Date: 14-06-2012
Publisher: Scientific Research Publishing, Inc.
Date: 2013
Publisher: Elsevier BV
Date: 12-2011
DOI: 10.1016/J.JCHB.2011.10.001
Abstract: Tuberculosis is a re-emerging disease and is a major problem in both developing and developed countries today. An estimated one third of the world's population is infected and almost two million people die from the disease each year. Bone lesions occur in 3-5% of active tuberculosis cases and can be used to diagnose the disease in ancient skeletal remains. A meta-analysis was conducted on 531 palaeopathological tuberculosis cases from 221 sites (7250 BCE to 1899) on all continents for the purpose of testing two hypotheses (1) the frequency of bone lesions does not change through time and (2) the distribution of lesions throughout the skeleton does not change over time. The frequency of bone lesions was found to significantly decrease over time (P<0.05). The distribution of bone lesions was found to change from mainly spinal in earlier time periods to include more cases in other regions of the skeleton (long bones, joints, hands, feet) in later time periods. This difference in distribution was evaluated using a Chi-squared test and found to be significant (P<0.01). These findings are an important addition to the current knowledge of the evolution of the disease and the Mycobacterium tuberculosis.
Publisher: Springer Science and Business Media LLC
Date: 03-05-2011
DOI: 10.1007/S00253-011-3294-3
Abstract: Increasingly, winemakers are looking for ways to introduce aroma and flavour ersity to their wines as a means of improving style and increasing product differentiation. While currently available commercial yeast strains produce consistently sound fermentations, there are indications that sensory complexity and improved palate structure are obtained when other species of yeast are active during fermentation. In this study, we explore a strategy to increase the impact of non-Saccharomyces cerevisiae inputs without the risks associated with spontaneous fermentations, through generating interspecific hybrids between a S. cerevisiae wine strain and a second species. For our experiments, we used rare mating to produce hybrids between S. cerevisiae and other closely related yeast of the Saccharomyces sensu stricto complex. These hybrid yeast strains display desirable properties of both parents and produce wines with concentrations of aromatic fermentation products that are different to what is found in wine made using the commercial wine yeast parent. Our results demonstrate, for the first time, that the introduction of genetic material from a non-S. cerevisiae parent into a wine yeast background can impact favourably on the wine flavour and aroma profile of a commercial S. cerevisiae wine yeast.
Publisher: Indonesian Society for Microbiology
Date: 03-2012
DOI: 10.5454/MI.6.1.5
Publisher: Springer Science and Business Media LLC
Date: 25-11-2011
Publisher: American Chemical Society (ACS)
Date: 27-02-2018
Abstract: A 'stone fruit' aroma is important in many white wine varieties and styles, but little is known about the chemical basis of this wine aroma attribute. A set of Viognier and Chardonnay wines that featured 'stone fruit' aroma attributes were selected by a panel of wine experts. The selected wines were characterized by sensory descriptive analysis and detailed volatile chemical composition analyses. This comprehensive data also allowed Viognier wine to be profiled for the first time. By partial least-squares regression, several esters and fatty acids and benzaldehyde were indicated as contributing to the 'peach' attribute however, a reconstitution sensory study was unsuccessful in mimicking this attribute. A mixture of γ-lactones, monoterpenes, and aldehydes were positively correlated to the 'apricot' aroma, which were generally higher in the Viognier wines. Reconstitution studies confirmed that the monoterpenes linalool, geraniol, and nerol were the most important compounds for the mixture being perceived as having an 'apricot' aroma.
Publisher: Elsevier BV
Date: 04-2014
Abstract: This study aimed to assess bacterial spoilage of half shell Pacific and Sydney rock oysters during storage using microbial culture and 16S rRNA pyrosequencing. Odour and pH of oyster meats were also investigated. Estimation of microbiological counts by microbial culture highlighted growth of psychrotrophic bacteria. During storage, odour scores (a score describing deterioration of fresh odours where a score of 1 is fresh and 4 is completely spoiled) increased from 1.0 to 3.0 for Pacific oysters and from 1.3 to 3.4 for Sydney rock oysters. pH results obtained for both species fluctuated during storage (range 6.28-6.73) with an overall increase at end of storage. Pyrosequencing revealed that the majority of bacteria at Day 0 represented taxa from amongst the Proteobacteria, Tenericutes and Spirochaetes that have not been cultured and systematically described. During storage, Proteobacteria became abundant with Pseudoalteromonas and Vibrio found to be dominant in both oyster species at Day 7. Analysis of the pyrosequencing data showed significant differences in bacterial profiles between oyster species and storage time (both P = 0.001). As oysters spoiled, bacterial profiles between oyster species became more similar indicating a common spoilage profile. Data presented here provides detailed insight into the changing bacterial profile of shucked oysters during storage and has identified two genera, Pseudoalteromonas and Vibrio, as being important in spoilage of shucked oysters.
Publisher: MDPI AG
Date: 24-10-2020
DOI: 10.3390/MICROORGANISMS8111647
Abstract: Pseudomonas aeruginosa is an opportunistic pathogen displaying high intrinsic antimicrobial resistance and the ability to thrive in different ecological environments. In this study, the ability of P. aeruginosa to develop simultaneous resistance to multiple antibiotics and disinfectants in different natural niches were investigated using strains collected from clinical s les, veterinary s les, and wastewater. The correlation between biocide and antimicrobial resistance was determined by employing principal component analysis. Molecular mechanisms linking biocide and antimicrobial resistance were interrogated by determining gene expression using RT-qPCR and identifying a potential genetic determinant for co- and cross-resistance using whole-genome sequencing. A subpopulation of P. aeruginosa isolates belonging to three sequence types was resistant against the common preservative benzalkonium chloride and showed cross-resistance to fluoroquinolones, cephalosporins, aminoglycosides, and multidrug resistance. Of these, the epidemiological high-risk ST235 clone was the most abundant. The overexpression of the MexAB-OprM drug efflux pump resulting from amino acid mutations in regulators MexR, NalC, or NalD was the major contributing factor for cross-resistance that could be reversed by an efflux pump inhibitor. This is the first comparison of antibiotic-biocide cross-resistance in s les isolated from different ecological niches and serves as a confirmation of laboratory-based studies on biocide adapted isolates. The isolates from wastewater had a higher incidence of multidrug resistance and biocide-antibiotic cross-resistance than those from clinical and veterinary settings.
No related grants have been discovered for Miguel De Barros Lopes.