Project description:Calcium propionate supplementation mitigated adverse effects of incubation temperature shift on in vitro fermentation by modulating microbial composition
| PRJNA967362 | ENA
Project description:Enrichment culture of fermentation microorganisms
Project description:In this study, an in vitro antifungal growth experiment showed that the inhibitory rate of the MCF broth on pathogenic fungi (Fusarium oxysporum f. sp. lycopersici, Botrytis cinerea, Trichothecium roseum, and Colletotrichum gloeosporioides) was less than that of B. amyloliquefaciens culture fermentation (BCF). Moreover, the content and gene expression of lipopeptide antibiotics was also lower than that in the BCF group. However, the pot experiments based on irrigation with appropriately diluted fermentation broth showed that the biocontrol effect of MCF on tomato Fusarium wilt was significantly higher than that of TCF (T. longibrachiatum culture fermentation) and BCF, and was approximately 15.79% higher than that of the BTF group which made by mixing equivalent amounts of BCF and TCF. In MCF broth, two microorganisms antagonized and coexisted, and the growth of T. longibrachiatum was inhibited. Using transcriptomic methods, we speculated that MCF can up-regulate the expression of genes related to carbon and nitrogen metabolism, oxidation–reduction activity, sporulation, environmental information response and chemotaxis, and biosynthesis of secondary metabolites of B. amyloliquefaciens, which might enhance the nutrient substances metabolism and competitiveness, survival ability, colonisation, and adaptability to the environment to increase its biocontrol potential.
2021-06-02 | GSE175908 | GEO
Project description:Effects of nitrogen addition on rhizosphere soil microorganisms
| PRJNA673644 | ENA
Project description:Sequencing results of rumen fermentation microorganisms in vitro
Project description:Propionate is an abundant carboxylic acid in nature. Microorganisms metabolize propionate aerobically via the 2-methylcitrate pathway. This pathway depends on a series of three reactions in the citric acid cycle that leads to the conversion of succinate to oxaloacetate. Interestingly, the gamma-proteobacterium Escherichia coli can use propionate as a carbon and electron source under oxic but not under anoxic conditions. The typical downregulation of the citric acid cycle under anoxic conditions is only partially responsible for the inability to use propionate under anoxic conditions since an arcA mutant shows very limited growth on propionate. RT-PCR and transcriptomic analysis revealed a post-transcriptional regulation of the prp-genecluster encoding the necessary enzymes for propionate metabolism. The polycistronic mRNA was hydrolyzed in the 3`-5` direction under anoxic conditions. This regulatory strategy is highly constructive because the last gene of the operon encodes the first enzyme of the propionate metabolism. Further analysis revealed that RNase R catalyzes the hydrolysis of the prp transcripts. Consequently, an rnr-deletion strain could metabolize propionate under anoxic conditions. To the best of our knowledge, this is the first study describing the influence of RNase R on the anaerobic metabolism of E. coli.
Project description:Acetate is a simple carboxylic acid that is synthesized in various microorganisms. Although acetate toxicity and tolerance have been studied in many microorganisms, little is known about the effects of exogenous acetate on the cell growth of acetogenic bacteria. In this study, we report the phenotypic changes that occurred in the acetogenic bacterium Clostridium sp. AWRP as a result of an adaptive laboratory evolution under acetate challenge. When compared with the wild-type strain, the acetate-adapted strain displayed a tolerance to acetate up to 10 g L-1 and higher biomass yields in batch cultures, although the metabolite profiles greatly varied depending on culture conditions. Interestingly, genome sequencing revealed that the adapted strain harbored three point mutations in the genes encoding an electron-bifurcating hydrogenase, which is crucial to its autotrophic growth on CO2 + H2, in addition to one in the dnaK gene. Transcriptome analysis revealed the global change in the gene expression profile of the acetate-adapted strain. Strikingly, most genes involved in CO2-fixing Wood-Ljungdahl pathway and auxiliary pathways for energy conservation (e.g., Rnf complex, Nfn, etc.) were significantly down-regulated. In addition, we observed that a couple of metabolic pathways associated with dissimilation of nucleosides and carbohydrates were significantly up-regulated in the acetate-adapted strain as well as several amino acid biosynthetic pathways, indicating that the strain might increase its fitness by utilizing organic substrates in response to the down-regulation of carbon fixation. Further investigation into the carbon fixation degeneration of the acetate-adapted strain will provide practical implications in CO2 + H2 fermentation using acetogenic bacteria for long-term continuous fermentation. The transcriptome profiles of the wild-type Clostridium sp. AWRP and its acetate-tolerant derivative 46T-a were compared.
Project description:Short chain fatty acids (SCFAs) are immunomodulatory compounds produced by the microbiome through fermentation of dietary fibre. Although they are generally considered beneficial for gut health, patients suffering from inflammatory bowel disease (IBD) have shown poor tolerance to fibre-rich diets, suggesting that SCFAs may have contrary effects under inflammatory conditions. To investigate this, we examined the effect of SCFAs on human macrophages in the presence of toll-like receptor agonists. In contrast to their anti-inflammatory effects under steady state conditions, we observed that the SCFAs butyrate and propionate triggered the activation of the NLRP3 inflammasome when added in conjunction with TLR agonists. Mechanistically, butyrate and propionate activated NLRP3 by inhibiting HDACs 1-3 and 10, leading to an uneven distribution of histone hyperacetylation that resulted in alterations in the transcriptome. Specifically, there was a lack of hyperacetylation at the loci of the CFLAR and IL10 genes, two important inhibitors of NLRP3 inflammasome activation. The concurrent loss of transcription and protein expression of cFLIP and IL-10 enabled caspase-8-dependent NLRP3-inflammasome activation. SCFA-driven NLRP3 activation did not require potassium efflux and did not result in cell death but rather triggered hyperactivation and IL-1b release. Our findings demonstrate that butyrate and propionate are bacterially-derived, viability-dependent danger signals (vita-PAMPs) that regulate NLRP3 inflammasome activation through epigenetic modulation of the inflammatory response.
2024-08-19 | GSE248577 | GEO
Project description:effects of incubation temperature shift on in vitro fermentation by modulating microbial composition archaca