Project description:Yeast whole cells have been widely used in modern biotechnology as biocatalysts to generate numerous compounds of industrial, chemical, and pharmaceutical importance. Since many of the biocatalysis utilizing manufactures have become more concerned about environmental issues, seawater is now considered a sustainable alternative to freshwater for biocatalytic processes. This approach plausibly commenced new research initiatives into exploration of salt tolerant yeast strains. Recently, there has also been a growing interest in possible applications of microbial biofilms in the field of biocatalysis. In these complex communities, cells demonstrate higher resistance to adverse environmental conditions due to their embedment in an extracellular matrix, in which physical, chemical, and physiological gradients exist. Considering these two topics, seawater and biofilms, in this work we characterized biofilm formation in seawater-based growth media by several salt tolerant yeast strains with previously demonstrated bocatalytic capacities. The tested strains formed both air-liquid-like biofilms and biofilms on silicone surfaces, with Debaryomyces fabryi, Schwanniomyces etchellsii, S. polymorphus and Kluyveromyces marxianus showing the highest biofilm formation. The extracted biofilm extracellular matrices mostly consisted of carbohydrates and proteins. The latter group was primarily represented by enzymes involved in metabolic processes, particularly the biosynthetic ones, and in the response to stimuli. Specific features were also found in the carbohydrate composition of the extracellular matrix, which were dependent both on the yeast isolate and the nature of formed biofilms. Overall, our findings presented herein provide a unique data resource for further development and optimization of biocatalytic processes and applications employing seawater and halotolerant yeast biofilms.
Project description:To elucidate how does the gene expression profiles of whole transcriptome of P.fucata response to seawater acidification and warming, we have employed microarray as a tool to identify gene responses in these stress.The pearl oysters were added into the tanks with the maintaining conditions of temperature 25 °C and 31 °C, acidity pH7.8 and pH7.5, salinity 33‰ in recirculating seawater. The temperatures and pH values in the studies were near future levels and predicted for 2100 and 2300.
Project description:To test whether elevated CO2 , which drives seawater below pH 7.9, would shift the dynamical expression patterns diatoms in a more natural environment, we designed a controlled mesocosm study at Friday Harbor Laboratories (FHL) Ocean Acidification Environmental Laboratory (OAEL). Briefly, four independent mesocosm tanks were set up with continuous flow (10-12 mL/min) of filtered seawater from the Puget Sound to simulate mid-century (pH 7.9) and acidified oceanic conditions (pH 7.6) in duplicate. Mesocosm reservoirs were supplemented with nutrients and inoculated with T. pseudonana acclimated in FHL seawater. Mesocosms were outfitted with custom enclosures to simulate a 12:12 light:dark diel cycle. Cells for RNA extraction were sampled in the middle of the light and dark cycle and sequenced on Illumina NextSeq 500 platform.
Project description:The physiological and transcriptional response of Nitrosomonas europaea biofilms to phenol and toluene was examined and compared to suspended cells. Biofilms were grown in Drip Flow Biofilm Reactors under continuous flow conditions of growth medium containing ammonia as growth substrate. The responses of N. europaea biofilms to the aromatic hydrocarbons phenol and toluene were determined during short-term (3 h) additions of each compound to the biofilms. Ammonia oxidation in the biofilms was inhibited 50% by 60 uM phenol and 100 uM toluene. These concentrations were chosen for microarray analysis of phenol- and toluene-exposed N. europaea biofilms. Liquid batch cultures of exponentially growing N. europaea cells were harvested alongside the biofilms to determine differential gene expression between attached and suspended growth of N. europaea.
Project description:To elucidate the modulatory participation of miRNAs in mollusk biomineralization, we have employed high-throughput sequencing to identify miRNAs of pearl oyster, Pinctada fucata. Our study focused on the miRNA expression profile of the mantle, an organ responsible for shell formation of the oyster. The pearl oysters were cultured in the tank with the maintaining conditions of temperature 19 ℃, PH 8.1 and salinity 33‰ in recirculating seawater.
Project description:Transcriptional profiling of C. albicans when monocultured in suspension culture or in biofilms compared to when co-cultured with C. perfringens in suspension culture, or with E. coli, K. pneumoniae, E. faecalis, C. perfringens, or B. fragilis in biofilms, or in the presence of N-acetylglucosamine in biofilms. At least 2 replicates for each condition except for biofilms +N-acetylglucosamine, some experiments are two-condition experiments: C. albicans +/- bacteria vs. C. albicans. Some experiments multiple condition: C. albicans +/- bacteria vs. mixed reference of all conditions in that experiment.
Project description:5 conditions for RNA-sequencing: Mono-culture biofilms of C. difficile WT, C. difficile luxS mutant (insertional ClosTron mutant as described in DOI: 10.1128/JB.01980-12), B. fragilis (PRJEB29695), and co-cultures biofilms of C. difficile WT and luxS mutant with B. fragilis. These were used to compare differences between C. difficile WT and luxS during mono-culture biofilms, as well transcriptomic differences for both C. difficile and B. fragilis during co-culture.