Project description:The present work aimed to compare the transcriptome of three major ethanol-producer Saccharomyces cerevisiae strains in Brazil when fermenting sugarcane juice for fuel ethanol production. This was motivated by the reports presenting physiological and genomics differences among them, and by the attempt to identify genes that could be related to their fermentation capacity and adaptation for different industrial processes.
Project description:Candida glabrata is a human-associated opportunistic fungal pathogen. It shares its niche with Lactobacillus spp. in the gastrointestinal and vaginal tract. In fact, Lactobacillus species are thought to competitively prevent Candida overgrowth. We investigated the molecular aspects of this antifungal effect by analyzing the interaction of C. glabrata strains with Limosilactobacillus fermentum. From a collection of clinical C. glabrata isolates, we identified strains with different sensitivities to L. fermentum in coculture. We analyzed the variation of their expression pattern to isolate the specific response to L. fermentum. C. glabrata-L. fermentum coculture induced genes associated with ergosterol biosynthesis, weak acid stress, and drug/chemical stress. L. fermentum coculture depleted C. glabrata ergosterol. The reduction of ergosterol was dependent on the Lactobacillus species, even in coculture with different Candida species. We found a similar ergosterol-depleting effect with other lactobacillus strains (Lactobacillus crispatus and Lactobacillus rhamosus) on Candida albicans, Candida tropicalis, and Candida krusei. The addition of ergosterol improved C. glabrata growth in the coculture. Blocking ergosterol synthesis with fluconazole increased the susceptibility against L. fermentum, which was again mitigated by the addition of ergosterol. In accordance, a C. glabrata Derg11 mutant, defective in ergosterol biosynthesis, was highly sensitive to L. fermentum. In conclusion, our analysis indicates an unexpected direct function of ergosterol for C. glabrata proliferation in coculture with L. fermentum.
Project description:The present work aimed to compare the transcriptome of three major ethanol-producer Saccharomyces cerevisiae strains in Brazil when fermenting sugarcane juice for fuel ethanol production. This was motivated by the reports presenting physiological and genomics differences among them, and by the attempt to identify genes that could be related to their fermentation capacity and adaptation for different industrial processes. Two-condition experiment, T0h vs. T6h fermetations assay. Biological replicates: 3 T0h replicates, 5 T6h replicates.
Project description:Fuel ethanol is now considered a global energy commodity that is fully competitive with gasoline. We have determined genome copy number differences that are common to five industrially important fuel ethanol yeast strains responsible for the production of billions of gallons of fuel ethanol per year from sugarcane. The fuel strains used were CAT1, BG1, PE2, SA1, and VR1 (note that two independent isolates were analyzed, denoted by "-1" and "-2"). These array-CGH data were compared with array-CGH data from nine other non-fuel industrial yeasts: An ale brewing strain ("Sc-ale"), four wine strains (GSY2A, GSY3A, GSY10A, GSY11B), and 4 bakers' yeast strains (GSY149, GSY150, GSY154, GSY155). Our results reveal significant amplifications of the telomeric SNO and SNZ genes only in the fuel strains, whose protein products are involved in the biosynthesis of vitamins B6 (pyridoxine) and B1 (thiamin). We show that these amplifications allow these yeasts to grow efficiently, especially at high sugar concentrations, regardless of the presence or absence of either of the two vitamins. Our results reveal important genetic adaptations that have been selected for in the industrial environment, which may be required for the efficient fermentation of biomass-derived sugars from other renewable feedstocks. A strain or line experiment design type assays differences between multiple strains, cultivars, serovars, isolates, lines from organisms of a single species. Strain Name: fuel strains used for aCGH
Project description:MUC5B is the predominant glycoprotein in saliva and is instrumental in the establishment and maintenance of multi-species eubiotic biofilms in the oral cavity. Investigations of the aciduric Lactobacillaceae family, and its role in biofilms emphasizes the diversity across different genera of the proteolytic systems involved in the nutritional utilization of mucins. We have characterized a cysteine protease from Limosilactobacillus fermentum, MdpL (Mucin degrading protease from Limosilactobacillus) with a high protein backbone similarity with commensals that exploit mucins for attachment and nutrition. MdpL was shown to be associated with the bacterial cell surface, in close proximity to MUC5B, which was sequentially degraded into low molecular weight fragments. Mapping the substrate preference revealed multiple hydrolytic sites of proteins with a high O-glycan occurrence, although hydrolysis was not dependent on the presence of O-glycans. However, since proteolysis of immunoglobulins was absent, and general protease activity was low, a preference for glycoproteins similar to MUC5B in terms of glycosylation and structure is suggested. MdpL preferentially hydrolyzed C-terminally located hydrophobic residues in peptides larger than 20 amino acids, which hinted at a limited sequence preference. To secure proper enzyme folding and optimal conditions for activity, L. fermentum incorporates a complex system that establishes a reducing environment. The importance of overall reducing conditions was confirmed by the activity boosting effect of the added reducing agents L-cysteine and DTT. High activity was retained in low to neutral pH 5.5-7.0, but the enzyme was completely inhibited in the presence of Zn2+. Here we have characterized a highly conserved mucin degrading protease from L. fermentum. MdpL, that together with the recently discovered O-glycanase and O-glycoprotease enzyme groups, increases our understanding of mucin degradation and complex biofilm dynamics.