Project description:Vibrio species represent one of the most diverse genera of marine bacteria known for their ubiquitous presence in natural aquatic systems. Several members of this genus including Vibrio harveyi are receiving increasing attention lately because they are becoming a source of health problems, especially for some marine organisms widely used in sea food industry. To learn about adaptation changes triggered by V. harveyi during its long-term persistence at elevated temperatures, we studied adaptation of this marine bacterium in sea water microcosms at 30 oC that closely mimicks the upper limits of sea surface temperatures recorded around the globe.
Project description:Previous studies have demonstrated that the iron content in marine heterotrophic bacteria is comparatively higher than that of phytoplankton. Therefore, they have been indicated to play a major role in the biogeochemical cycling of iron. In this study, we aimed to investigate the potential of viral lysis as a source of iron for marine heterotrophic bacteria. Viral lysates were derived from the marine heterotrophic bacterium, Vibrio natriegens PWH3a (A.K.A Vibrio alginolyticus). The bioavailability of Fe in the lysates was determined using a model heterotrophic bacterium, namely, Dokdonia sp. strain Dokd-P16, isolated from Fe-limited waters along Line P transect in the Northeastern Pacific Ocean. The bacteria were grown under Fe-deplete or Fe-replete conditions before being exposed to the viral lysate. Differential gene expression following exposure to the viral lysate was analyzed via RNA sequencing to identify differentially expressed genes under iron-replete and iron-deplete conditions. This study would provide novel insights into the role of viral lysis in heterotrophic bacteria in supplying bioavailable iron to other marine microorganisms under iron-limiting and non-limiting conditions. First, the marine heterotrophic bacterium genome, Dokdonia sp. strain Dokd-P16, was sequenced to provide a genomic context for the expression studies. Subsequently, the relative gene expression in Dokdonia sp. strain Dokd-P16 grown under Fe limiting and non-limiting conditions were analyzed. This transcriptomic approach would be utilized to elucidate genes regulated by Fe availability in Dokdonia sp. strain Dokd-P16, which indicate its Fe-related response viral lysate exposure. Taken together, in this study, the transcriptomic responses of Fe-limited and non-limited marine heterotrophic bacteria were analyzed, which provided novel insights into the biological availability of Fe from the viral lysates.
Project description:Hypocrea jecorina (anamorph Trichoderma reesei) is one of the most well studied fungi used in biotechnology industry. This fungus is today a paradigm for the comercial scale production of different plant cell wall degrading enzymes, mainly cellulases and hemicellulases. The objective of this study was to analyze the transcriptional profiling of T. reesei (Δxyr1) grown in presence of cellulose, sophorose and glucose as the carbon source using RNA-seq approach.
Project description:Hypocrea jecorina (anamorph Trichoderma reesei) is one of the most well studied fungi used in biotechnology industry. This fungus is today a paradigm for the comercial scale production of different plant cell wall degrading enzymes, mainly cellulases and hemicellulases. The objective of this study was to analyze the transcriptional profiling of T. reesei grown in presence of cellulose, sophorose and glucose as the carbon source using RNA-seq approach.
Project description:The induction of genes in response to exposure of T. reesei to wheat straw was explored using genome-wide RNA-seq and compared to published RNA-seq data and model of how A. niger senses and responds to the lignocellulose. After 24 h of exposure to straw, transcript levels of known and predicted lignocellulose-degrading enzymes increased to around 8% of total cellular mRNA in T. reesei, which was much less when compared to A. niger. The bulk of enzymes used to deconstruct wheat straw is similar in both fungi. Other, non-plant cell wall-degrading enzymes which may aid in lignocellulose degradation were also uncovered in T. reesei and similar to those described in A. niger. Antisense transcripts were also shown to be present in T. reesei and their expession can be regulated by the respective growth condition. Triplicate samples of T. reesei cultivated in each of the three following conditions were taken: 1) After 48 h growth in glucose-based minimal media; 2) After transfer of mycelia from glucose-based media into media containing wheat straw as a sole carbon source and 3) 5 h after addition of glucose to straw cultures.