International journal of systematic and evolutionary microbiology 20140820 Pt 11
While characterizing a related strain, it was noted that there was little difference between the 16S rRNA gene sequences of Bacillus indicus LMG 22858(T) and Bacillus cibi DSM 16189(T). Phenotypic characterization revealed differences only in the utilization of mannose and galactose and slight variation in pigmentation. Whole genome shotgun sequencing and comparative genomics were used to calculate established phylogenomic metrics and explain phenotypic differences. The full, genome-derived 16S ...[more]
Project description:Ruminiclostridium thermocellum DSM 1313 strain adhE*(EA) expression was studied along with ∆hydG and ∆hydG∆ech mutants strains deposited under GSE54082. All strains have been described in a study entitled Elimination of hydrogenase post-translational modification blocks H2 production and increases ethanol yield in Clostridium thermocellum. Biswas, et .al. Biotechnology for Biofuels 2015 8:20 Ruminiclostridium (Clostridium) thermocellum is a leading candidate organism for implementing a consolidated bioprocessing (CBP) strategy for biofuel production due to its native ability to rapidly consume cellulose and its existing ethanol production pathway. C. thermocellum converts cellulose and cellobiose to lactate, formate, acetate, H2, ethanol, amino acids, and other products. Elimination of the pathways leading to products such as H2 could redirect carbon flux towards ethanol production. Rather than delete each hydrogenase individually, we targeted a hydrogenase maturase gene (hydG), which is involved in converting the three [FeFe] hydrogenase apoenzymes into holoenzymes by assembling the active site. This functionally inactivated all three Fe-Fe hydrogenases simultaneously, as they were unable to make active enzymes. In the ∆hydG mutant, the [NiFe] hydrogenase-encoding ech was also deleted to obtain a mutant that functionally lacks all hydrogenase. The ethanol yield increased nearly 2-fold in ∆hydG∆ech compared to wild type, and H2 production was below the detection limit. Interestingly, ∆hydG and ∆hydG∆ech exhibited improved growth in the presence of acetate in the medium. Transcriptomic and proteomic analysis reveal that genes related to sulfate transport and metabolism were up-regulated in the presence of added acetate in ∆hydG, resulting in altered sulfur metabolism. Further genomic analysis of this strain revealed a mutation in the bi-functional alcohol/aldehyde dehydrogenase adhE gene, resulting in a strain with both NADH- and NADPH-dependent alcohol dehydrogenase activities, whereas the wild type strain can only utilize NADH. This is the exact same adhE mutation found in ethanol-tolerant C. thermocellum strain E50C, but ∆hydG∆ech is not more ethanol tolerant than the wild type. Targeting protein post-translational modification is a promising new approach to target multiple enzymes simultaneously for metabolic engineering. This GEO study pertains to expression profiles generated for C. thermocellum DSM 1313 strain adhE*(EA) Overall design: A six array study using total RNA recovered from Clostridium thermocellum DSM 1313 adhE*(EA) 27405 cultures. Cells were harvested at an OD 0.4-0.5 from cultures grown in the presence of additional 5mM acetate and compared to untreated controls. Three biological replicates were performed for treated and untreated cultures.
Project description:Investigation of whole genome gene expression level changes in sporulating Bacillus subtilis 168 delta-prpE mutant, compared to the wild-type strain. The mutation engineered into this strain results in impaired germination of spores. A six chip study using total RNA extracted from three separate wild-type cultures of sporulating Bacillus subtilis 168 and three separate cultures of sporulating mutant strain, Bacillus subtilis 168 delta-prpE, in which prpE (yjbP BSU11630) gene coding for a protein phosphatase is deleted entirely. Each chip consists of four fields able to measure the expression level of 4,104 genes from Bacillus subtilis subsp. subtilis strain 168 NC_000964 with eight 60-mer probe pairs (PM/MM) per gene, with two-fold technical redundancy.