Project description:The transcriptional responses of Prevotella ruminicola were determined during growth on 20 different carbohydrate sources including mono-, di- and tri- saccharides, oligosaccharides, polymeric xylan and complete plant material with the aim of obtaining a more complete understanding of the number of genes and metabolic networks associated with carbohydrate catabolism by this organism All microarray hybridizations and subsequent scanning was undertaken using a two colour system (Cy3 and Cy5): 34 samples
Project description:The transcriptional responses of Prevotella ruminicola were determined during growth on 20 different carbohydrate sources including mono-, di- and tri- saccharides, oligosaccharides, polymeric xylan and complete plant material with the aim of obtaining a more complete understanding of the number of genes and metabolic networks associated with carbohydrate catabolism by this organism
Project description:We performed shotgun proteomics on the bacteria Prevotella brevis GA33 and Prevotella ruminicola 23. We did this for two types of samples (cell extract and cell membrane) and using two methods (data-dependent and data-independent acquisition).
Project description:BackgroundSaccharomyces cerevisiae strains expressing D-xylose isomerase (XI) produce some of the highest reported ethanol yields from D-xylose. Unfortunately, most bacterial XIs that have been expressed in S. cerevisiae are either not functional, require additional strain modification, or have low affinity for D-xylose. This study analyzed several XIs from rumen and intestinal microorganisms to identify enzymes with improved properties for engineering S. cerevisiae for D-xylose fermentation.ResultsFour XIs originating from rumen and intestinal bacteria were isolated and expressed in a S. cerevisiae CEN.PK2-1C parental strain primed for D-xylose metabolism by over expression of its native D-xylulokinase. Three of the XIs were functional in S. cerevisiae, based on the strain's ability to grow in D-xylose medium. The most promising strain, expressing the XI mined from Prevotella ruminicola TC2-24, was further adapted for aerobic and fermentative growth by serial transfers of D-xylose cultures under aerobic, and followed by microaerobic conditions. The evolved strain had a specific growth rate of 0.23 h-1 on D-xylose medium, which is comparable to the best reported results for analogous S. cerevisiae strains including those expressing the Piromyces sp. E2 XI. When used to ferment D-xylose, the adapted strain produced 13.6 g/L ethanol in 91 h with a metabolic yield of 83% of theoretical. From analysis of the P. ruminicola XI, it was determined the enzyme possessed a Vmax of 0.81 μmole/min/mg protein and a Km of 34 mM.ConclusionThis study identifies a new xylose isomerase from the rumen bacterium Prevotella ruminicola TC2-24 that has one of the highest affinities and specific activities compared to other bacterial and fungal D-xylose isomerases expressed in yeast. When expressed in S. cerevisiae and used to ferment D-xylose, very high ethanol yield was obtained. This new XI should be a promising resource for constructing other D-xylose fermenting strains, including industrial yeast genetic backgrounds.
Project description:The goal of this project is to dissect the mechanism by which Tc1 and Tc2 effector subtypes effect cell physiology in vitro. I utilized cellular proteomics to determine Tc1 and Tc2 secretion patterns and identify inflammatory factors that regulate cell polarization and physiology in vitro.