Efflux Pump-Driven Antibiotic and Biocide Cross-Resistance in Isolated from Different Ecological Niches: A Case Study in the Development of Multidrug Resistance in Environmental Hotspots.

is an opportunistic pathogen displaying high intrinsic antimicrobial resistance and the ability to thrive in different ecological environments. In this study, the ability of to develop simultaneous resistance to multiple antibiotics and disinfectants in different natural niches were investigated using strains collected from clinical samples, veterinary samples, and wastewater. The correlation between biocide and antimicrobial resistance was determined by employing principal component analysis.

Factors Contributing to Interindividual Variation in Retronasal Odor Perception from Aroma Glycosides: The Role of Odorant Sensory Detection Threshold, Oral Microbiota, and Hydrolysis in Saliva.

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 interindividual 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 hydrolysis of glucosides in saliva, metagenomic screening was conducted using individuals representing the range of sensory phenotypes for geranyl and guaiacyl glucosides.

Analysis, potency and occurrence of (Z)-6-dodeceno-γ-lactone in white wine.

(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.

Investigation of 'stone fruit' aroma in Chardonnay, Viognier and botrytis Semillon wines.

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.

Volatile Compounds Related to 'Stone Fruit' Aroma Attributes in Viognier and Chardonnay Wines.

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.

Design, synthesis and biological activity evaluation of novel 4-subtituted 2-naphthamide derivatives as AcrB inhibitors.

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.

Evaluation of a series of 2-napthamide derivatives as inhibitors of the drug efflux pump AcrB for the reversal of antimicrobial resistance.

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.

A microbial spoilage profile of half shell Pacific oysters (Crassostrea gigas) and Sydney rock oysters (Saccostrea glomerata).

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.

Polymorphisms in the mitochondrial ribosome recycling factor EF-G2mt/MEF2 compromise cell respiratory function and increase atorvastatin toxicity.

Mitochondrial translation, essential for synthesis of the electron transport chain complexes in the mitochondria, is governed by nuclear encoded genes. Polymorphisms within these genes are increasingly being implicated in disease and may also trigger adverse drug reactions. Statins, a class of HMG-CoA reductase inhibitors used to treat hypercholesterolemia, are among the most widely prescribed drugs in the world.

Newly generated interspecific wine yeast hybrids introduce flavour and aroma diversity to wines.

Increasingly, winemakers are looking for ways to introduce aroma and flavour diversity 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.

The MEF2 gene is essential for yeast longevity, with a dual role in cell respiration and maintenance of mitochondrial membrane potential.

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.

Proline transport and stress tolerance of ammonia-insensitive mutants of the PUT4-encoded proline-specific permease in yeast.

The imino amino acid, proline, has roles in both cellular nutrition and response to stress. Proline uptake in Saccharomyces cerevisiae is largely mediated by a high affinity, specific permease, Put4p, and a low affinity general amino acid permease, Gap1p. Both are subject to nitrogen catabolite repression (NCR) and nitrogen catabolite inactivation (NCI).

Atorvastatin-induced cell toxicity in yeast is linked to disruption of protein isoprenylation.

Statins, used to treat hypercholesterolemia, are one of the most frequently prescribed drug classes in the developed world. However, a significant proportion of users suffer symptoms of myotoxicity, and currently, the molecular mechanisms underlying myotoxicity remain ambiguous. In this study, Saccharomyces cerevisiae was exploited as a model system to gain further insight into the molecular mechanisms of atorvastatin toxicity.

Hpf2 glycan structure is critical for protection against protein haze formation in white wine.

Grape-derived proteins can form haze in wine. Some cell-wall glycoproteins of Saccharomyces cerevisiae are capable of reducing protein haze formation. The basis of their haze protective activity is not yet understood.

Genetic diversity of Dekkera bruxellensis yeasts isolated from Australian wineries.

Yeasts of the genus Dekkera and its anamorph Brettanomyces represent a significant spoilage issue for the global wine industry. Despite this, there is limited knowledge of genetic diversity and strain distribution within wine and winery-related environments. In this study, amplified fragment length polymorphism (AFLP) analysis was conducted on 244 Dekkera bruxellensis isolates from red wine made in 31 winemaking regions of Australia.

Reducing haziness in white wine by overexpression of Saccharomyces cerevisiae genes YOL155c and YDR055w.

Grape proteins aggregate in white wine to form haze. A novel method to prevent haze in wine is the use of haze protective factors (Hpfs), specific mannoproteins from Saccharomyces cerevisiae, which reduce the particle size of the aggregated proteins. Hpf1p was isolated from white wine and Hpf2p from a synthetic grape juice fermentation.

Genetic determinants of volatile-thiol release by Saccharomyces cerevisiae during wine fermentation.

Volatile thiols, particularly 4-mercapto-4-methylpentan-2-one (4MMP), make an important contribution to the aroma of wine. During wine fermentation, Saccharomyces cerevisiae mediates the cleavage of a nonvolatile cysteinylated precursor in grape juice (Cys-4MMP) to release the volatile thiol 4MMP. Carbon-sulfur lyases are anticipated to be involved in this reaction.

Identification of genes affecting glucose catabolism in nitrogen-limited fermentation.

In recognition of the importance of assimilable nitrogen in the successful completion of several fermentation processes, we have sought to develop yeast strains that utilise this typically limited nutrient group more efficiently. With the aid of transposon mutagenesis together with a high-throughput method for analysis of multiple fermentations, we have identified 'nitrogen-efficient' mutants that catabolise more sugar for a given amount of nitrogen utilised. In this way we have identified two genes, NGR1 and GID7, whose disruption leads to an enhanced catabolism of sugar in an industrial strain and/or a laboratory strain, during growth in a chemically defined grape juice medium with limiting nitrogen.

Variation in 4-mercapto-4-methyl-pentan-2-one release by Saccharomyces cerevisiae commercial wine strains.

The volatile thiol 4-mercapto-4-methylpentan-2-one (4MMP) is a potent contributor to wine aroma. In grape juice, 4MMP is bound to cysteine as a non-volatile compound and requires the action of yeast during fermentation to release the aroma active thiol. A method was developed to measure 4MMP release from the precursor by headspace solid-phase microextraction and separation by gas chromatography with atomic emission detection to screen the ability of wine yeast to release 4MMP.

Application of the reuseable, KanMX selectable marker to industrial yeast: construction and evaluation of heterothallic wine strains of Saccharomyces cerevisiae, possessing minimal foreign DNA sequences.

The characterisation of wine yeasts and the complex metabolic processes influencing wine fermentation and the quality of wine might best be achieved by exploiting the standard classical and recombinant genetic techniques which have been successfully used with laboratory strains. However, application of these techniques to industrial strains has been restricted because such strains are typically prototrophic and often polyploid. To overcome this problem, we have identified commercial wine strains with good mating and sporulation properties from which heterothallic derivatives were constructed by disruption of the HO gene.

Human wild-type SEDL protein functionally complements yeast Trs20p but some naturally occurring SEDL mutants do not.

X-linked spondyloepiphyseal dysplasia tarda (SEDT, or SEDL) is a primary skeletal dysplasia affecting mostly spinal vertebral bodies and epiphyses. Previously, we have identified the SEDL gene and determined the spectrum of 21 different SEDL causing mutations. The SEDL gene is a highly conserved gene with an as yet unknown function.

Evidence for multiple interspecific hybridization in Saccharomyces sensu stricto species.

Fluorescent amplified fragment length polymorphism analysis demonstrates a high level of gene exchange between Saccharomyces sensu stricto species, with some strains having undergone multiple interspecific hybridization events with subsequent changes in genome complexity. Two lager strains were shown to be hybrids between Saccharomyces cerevisiae and the alloploid species Saccharomyces pastorianus. The genome structure of CBS 380(T), the type strain of Saccharomyces bayanus, is also consistent with S.

Decreasing acetic acid accumulation by a glycerol overproducing strain of Saccharomyces cerevisiae by deleting the ALD6 aldehyde dehydrogenase gene.

Glycerol is a major fermentation product of Saccharomyces cerevisiae that contributes to the sensory character of wine. Diverting sugar to glycerol overproduction and away from ethanol production by overexpressing the glycerol 3-phosphate dehydrogenase gene,GPD2, caused S. cerevisiae to produce more than twice as much acetic acid as the wild-type strain (S288C background) in anaerobic cell culture.