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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.
2016-12-01 | GSE80782 | GEO
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.
2016-12-01 | GSE80781 | GEO
Project description:Design: double blind controlled randomized trial with a parallel design and 3 treatment groups Description of subjects: Patients admitted in study centers for colorectal surgery under laporoscopy and/or laparotomy.
Product:
Product 1: BB536 and LA1 (10E9) Product 2: BB536 and LA1 (10E7) Placebo: Maltodextrin Number of patients: enrolled subjects: n=33, ITT data set: n=31, PP data set: n=30
Primary objective:
Colonization (biopsy+stools) of each bacteria for one of the dose at D0 (surgical procedure)
Secondary objectives:
* Influence of the probiotic bacteria on the gut microflora
* Modulation of the immune and inflammatory response
Additional objectives:
* Investigate dose effect on La1 colonization
* Investigate the effect of La1 colonization, treatment without La1 colonization, and absence of treatment and La1 colonization on other bacteria and on immunological parameters
| 2074940 | ecrin-mdr-crc
Project description:Understanding the strategies used by bacteria to degrade polysaccharides constitutes an invaluable tool for biotechnological applications Bacteria are major mediators of polysaccharide degradation in nature, however the complex mechanisms used to detect, degrade, and consume these substrates are not well understood, especially for recalcitrant polysaccharides such as chitin It has been previously shown that the model bacterial saprophyte Cellvibrio japonicus is able to catabolize chitin, but little is known about the enzymatic machinery underlying this capability Previous analyses of the C japonicus genome and proteome indicated the presence of four family 18 Glycoside Hydrolase (GH18) enzymes, and studies of the proteome indicated that all are involved in chitin utilization Using a combination of in vitro and in vivo approaches, we have studied the roles of these four chitinases in chitin bioconversion Genetic analyses showed that only the chi18D gene product is essential for the degradation of chitin substrates Biochemical characterization of the four enzymes showed functional differences and synergistic effects during chitin degradation, indicating non-redundant roles in the cell Transcriptomic studies revealed complex regulation of the chitin degradation machinery of C japonicus and confirmed the importance of CjChi18D and CjLPMO10A, a previously characterized chitin-active enzyme With this systems biology approach, we deciphered the physiological relevance of the GH18 enzymes for chitin degradation in C japonicus, and the combination of in vitro and in vivo approaches provided a comprehensive understanding of the initial stages of chitin degradation by this bacterium
2018-01-24 | GSE108935 | GEO
Project description:Chitin utilization by microbes plays a significant role in cycling of carbon and nitrogen in the biosphere, and the study of the microbial approaches used to degrade chitin will facilitate our understanding of bacterial strategies to degrade this recalcitrant polysaccharide. The early stages of chitin depolymerization by the bacterium Cellvibrio japonicus have been characterized and are dependent on one chitin-specific lytic polysaccharide monooxygenase and non-redundant glycoside hydrolases from the family GH18 to generate chito-oligosaccharides for entry into metabolism. Here, we describe the mechanisms for the latter stages of chitin utilization by C. japonicus with an emphasis on the fate of chito-oligosaccharides. Our systems biology approach combined transcriptomics, bacterial genetics, and complex environmental substrates to determine the essential mechanisms for chito-oligosaccharide transport and catabolism in Cellvibrio japonicus. Using RNAseq analysis we found not only the up-regulation of genes that encode CAZymes specific for chitin metabolism but also a coordinated expression of non-chitin specific CAZyme genes. Furthermore, we used mutational analysis to characterize the hex20B gene product, predicted to encode a hexosaminidase, and found that it is required for efficient utilization of chito-oligosaccharides. Surprisingly, two additional gene loci (CJA_0353 and CJA_1157), which encode putative TonB-dependent transporters, were essential for shuttling chito-oligosaccharides into the periplasmic space. Here we propose naming these loci cttA (chito-oligosaccharides transporter A) and cttB respectively. This study further develops our model of how C. japonicus can derive nutrients from recalcitrant chitin-containing substrates and may be potentially useful for other environmentally or industrially important bacteria.
2020-04-30 | GSE149593 | GEO
Project description:External signals are key for bacteria to sense their immediate environment and fine-tune gene expression accordingly. The foodborne pathogen Listeria monocytogenes senses a range of environmental cues in order to activate or deactivate the virulence-inducing transcriptional factor PrfA during transition between infectious and saprophytic lifecycles. Chitin is an abundant biopolymer formed from linked β-(1–4)-N-acetyl-D-glucosamine residues associated with fungi, the exoskeleton of insects and often incorporated into foods as a thickener or stabiliser. L. monocytogenes evolved to hydrolyse chitin, presumably, to facilitate nutrient acquisition from competitive environments such as soil where the polymer is abundant. Since mammals do not produce chitin, we reasoned that the polymer could serve as an environmental signal contributing to repression of L. monocytogenes PrfA-dependent expression outside the host. This study shows a significant downregulation of the core PrfA-regulon during virulence-inducing conditions in vitro in the presence of chitin. Our data suggest this phenomenon occurs through a mechanism that differs from PTS-transport of oligosaccharides generated from either degradation or chitinase-mediated hydrolysis of the polymer. Importantly, an indication that chitin can repress virulence expression of a constitutively active PrfA* mutant is shown, possibly mediated via a post-translational modification inhibiting PrfA* activity. To our knowledge, chitin as a molecule with anti-virulence properties against a pathogenic bacterium has not been previously reported. Thus, our findings identify chitin as a signal which may downregulate the virulence potential of the pathogen and may provide an alternative approach towards reducing disease risk.
2020-12-22 | GSE154844 | GEO
Project description:Commensal bacteria shapes gut immune system. Colonization bacteria increase the frequency of regulatory T cells, however, the molecular mechanisms has not yet been unknown. To reveal the mechanism, we isolated Treg cells and Non-Treg cells and performed the global expression analysis.
2014-04-07 | GSE56542 | GEO
Project description:Commensal bacteria shapes gut immune system. Colonization bacteria increase the frequency of regulatory T cells, however, the molecular mechanisms has not yet been unknown. To reveal the mechanism, we isolated Treg cells and Non-Treg cells and performed the global expression analysis.
2015-06-10 | GSE47818 | GEO
Project description:Genome mining of pigmented Pseudoalteromonas has revealed a large potential for production of bioactive compounds, both hydrolytic enzymes and secondary metabolites and the purpose of the present study was to explore this bioactivity potential in a potent antibiotic and enzyme producer, Pseudoalteromonas rubra strain S4059. Proteomic analyses indicated that a highly efficient chitin degradation machinery was present in the red-pigmented P. rubra S4059 when grown on chitin. Four GH18 chitinases and two GH20 hexosaminidases were significantly upregulated by chitin. GH19 chitinase which is not common in bacteria is consistently found in pigmented Pseudoalteromonas and in S4059 it was only detected when the bacterium was grown on chitin. To explore the possible role of GH19 in pigmented Pseudoalteromonas, we deleted the GH19 chitinase and compared a range of phenotypes in the mutant and wild type. Neither, the chitin degrading ability or the biofilm forming capacity was affected by GH19 deletion. In some Vibrionaceae, the secondary metabolome is significantly affected by growth on chitin as compared to simpler carbon sources. The secondary metabolites produced by S4059 and the GH19 mutant were xxx start by chitin/mannose – then the mutant. not altered by the absence of the gene, indicating that chitin utilization may not directly influence the production of secondary metabolites as has been observed in some Vibrionaceae. Metabolome analysis reveal that growth on chitin XX. In summary,
2021-03-11 | PXD023249 | Pride