Project description:Members of the Vibrionaceae family are often found associated with chitin-containing organisms and they are thought to play a major role in chitin degradation. The purpose of the present study was to determine how chitin affected the transcriptome and metabolome of two bioactive Vibrionaceae strains, Vibrio corallilyticus and Photobacterium galatheae. We focused on chitin degradation genes and secondary metabolites based on the assumption that these molecules in nature confer an advantage to the producer. Growth on chitin caused up-regulation of genes related to chitin metabolism and of genes potentially involved in host colonization and/or infection. The expression of genes involved in secondary metabolism was also significantly affected by growth on chitin, in one case being thirty-four folds upregulated. This was reflected in the metabolome, where the antibiotics andrimid and holomycin were produced in higher amounts on chitin. Interestingly, in cultures of P. galatheae grown on chitin we detected high amounts of the biogenic amine phenylethylamine. Overall, these results suggest that both V. coralliilyticus and P. galatheae have a specific lifestyle for growth on chitin, and that the secondary metabolites they produce are likely to play a crucial role during chitin colonization.
Project description:Members of the Vibrionaceae family are often found associated with chitin-containing organisms and they are thought to play a major role in chitin degradation. The purpose of the present study was to determine how chitin affected the transcriptome and metabolome of two bioactive Vibrionaceae strains, Vibrio corallilyticus and Photobacterium galatheae. We focused on chitin degradation genes and secondary metabolites based on the assumption that these molecules in nature confer an advantage to the producer. Growth on chitin caused up-regulation of genes related to chitin metabolism and of genes potentially involved in host colonization and/or infection. The expression of genes involved in secondary metabolism was also significantly affected by growth on chitin, in one case being thirty-four folds upregulated. This was reflected in the metabolome, where the antibiotics andrimid and holomycin were produced in higher amounts on chitin. Interestingly, in cultures of P. galatheae grown on chitin we detected high amounts of the biogenic amine phenylethylamine. Overall, these results suggest that both V. coralliilyticus and P. galatheae have a specific lifestyle for growth on chitin, and that the secondary metabolites they produce are likely to play a crucial role during chitin colonization.
Project description:The marine bacterium Photobacterium galatheae S2753 produces a group of cyclodepsipeptides, solonamides, which impede the virulence but not the survival of Staphylococcus aureus. Besides the invaluable antivirulence activity, little is known about the biosynthesis and physiological function of solonamides in the native producer. This study generated a solonamides-deficient mutant, Δsol, by in-frame deleting the sol gene, thereby identifying the core gene for solonamides biosynthesis. By annotation from antiSMASH, the biosynthetic pathway of solonamides in S2753 was also proposed. Mass spectrometry analysis of cell extracts found that deficiency of solonamides production influenced the production of several novel lipids, but not the overall secondary metabolite profile. Physiological comparison between Δsol and wild-type S2753 demonstrated that growth dynamics and biofilm formation of both strains were similar; however, Δsol displayed reduced swimming rings as compared to the wild-type. The swimming ring size of Δsol was restored to the level of wild-type strain by adding solonamide B, indicating that solonamide B influences regulate the swimming behavior of P. galatheae S2753. Proteomic analysis of the Δsol and wild-type found that eliminating solonamides influenced many cellular processes, including swimming-related proteins and that solonamides trigger the motility of S2753 likely by adjusting the cellular cyclic di-GMP concentration. In conclusion, our results revealed the biosynthetic pathway of solonamides and their ecological benefits to P. galatheae S2753 by enhancing the swimming velocity, likely by altering the motile physiology.
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)
Project description:Here we report the massively parallel cDNA sequencing (RNA-seq) analysis performed using high throughput sequencing of wild type (DB110) and toxR (TW30) mutant strains of the deep-sea bacterium Photobacterium profundum. ToxR is a transmembrane DNA-binding protein first discovered in Vibrio cholerae and able to regulate numerous genes involved in virulence. In P. profundum the abundance and activity of the same protein is influenced by hydrostatic pressure and is able to regulate genes in a pressure-dependent manner. To better characterize the ToxR regulon, we have compared the genes differentially expressed in response to pressure changes with those whose expression is altered between wild type and toxR mutant strains. Four samples were analyzed: DB110 strain grown at 0.1 MPa, DB110 strain grown at 28 MPa, TW30 strain grown at 0.1 MPa, TW30 strain grown at 28 MPa. Two independent coltures (replicates) were grown for each sample, RNA was extracted from each replicate and RNAs from the two replicates were pooled together to reduce biological variability. No replicates were included in experimental design.
Project description:Investigation of whole genome gene expression level changes in Lactococcus lactis KCTC 3769T,L. raffinolactis DSM 20443T, L. plantarum DSM 20686T, L. fujiensis JSM 16395T, L. garvieae KCTC 3772T, L. piscium DSM 6634T and L. chungangensis CAU 28T . This proves that transcriptional profiling can facilitate in elucidating the genetic distance between closely related strains.