Project description:The industrially attractive biopolymer Poly-γ-glutamic acid (γ-PGA) is commonly produced by species of the genus Bacillus by co-feeding different carbon- and nitrogen sources. Recent studies have highlighted the pivotal role of co-metabolization of a rapidly degradable carbon source such as glycerol together with citrate for γ-PGA production, independently fueling biomass generation as well as TCA cycle precursor supply. With this study, we report that the sole presence of citrate in the production medium greatly influences growth behavior, γ-PGA production, and the viscosity of microbial cultures during biopolymer synthesis. Independent of the citrate concentration in the medium. only minor amounts of citrate were imported by B. subtilis 168 in presence of glycerol due to carbon catabolite repression. However, a high citrate concentration resulted in a 6-fold increase in γ-PGA titer as compared to low levels of exogenous citrate. Data suggests that citrate was not used as a precursor in γ-PGA synthesis but rather influenced the fate of imported glutamate. The citrate concentration also affected medium viscosity as depletion resulted in a remarkable spike in broth viscosity. Additionally, cellular proteome analysis at different levels of citrate availability revealed significant changes in protein abundance involved in motility and fatty acid degradation
Project description:FROG and miniFROG reports are given for the genome-scale metabolic network of Bacillus licheniformis WX-02. The model iWX1009 contains 1009 genes, 1141 metabolites and 1762 reactions and is the study of poly-γ-glutamic acid (γ-PGA) synthesis. The model can be found in the Supplementary data of the Guo et al, 2016 paper cited here.
Project description:The gene expression levels in murine bone marrow-derived dendritic cells treated with γ-PGA NPs were examined by oligonucleitide microarray and compared with those in the cells treated with other adjuvants. The gene expression of proinflammatory chemokines, cytokines, and costimulatory molecules was upregulated considerably in DCs treated with γ-PGA NPs. The upregulation pattern was similar to that in DCs treated with LPS but not in DCs treated with unparticulate γ-PGA. The activation of DCs by γ-PGA NPs was confirmed by real-time RT-PCR analysis for the genes related to TLR signaling. The effect of γ-PGA NPs on DCs was not annihilated by treating with polymixin B, an inhibitor of LPS. Furthermore, the immunization of mice with γ-PGA NPs carrying OVA significantly induced Ag-specific CD8+ T cells and Ag-specific production of IL-2, TNF-α, and IFN-γ from the cells. Such activities of γ-PGA NPs were more prominent, when compared to the immunization with OVA plus aluminum hydroxide or OVA plus CFA. These results suggest that γ-PGA NPs induce a CD8+ T cell response through activating innate immunity in a fashion different from that of LPS. Thus, γ-PGA NPs may be an attractive adjuvant to be further developed for vaccine therapy.
Project description:Identification of the specific WalR (YycF) binding regions on the B. subtilis chromosome during exponential and phosphate starvation growth phases. The data serves to extend the WalRK regulon in Bacillus subtilis and its role in cell wall metabolism, as well as implying a role in several other cellular processes.
Project description:Background. Bacillus subtilis is a favorable host for the production of industrially relevant proteins because of its capacity of secreting proteins into the medium to high levels, its GRAS (Generally Recognized As Safe) status, its genetic accessibility and its capacity to grow in large fermentations. However, production of heterologous proteins still faces limitations. Results. This study aimed at the identification of bottlenecks in secretory protein production by analyzing the response of B. subtilis at the transcriptome level to overproduction of eight secretory proteins of endogenous and heterologous origin and with different subcellular or extracellular destination: secreted proteins (NprE and XynA of B. subtilis, Usp45 of Lactococcus lactis, TEM-1beta -lactamase of Escherichia coli), membrane proteins (LmrA of L. lactis and XylP of Lactobacillus pentosus) and lipoproteins (MntA and YcdH of B. subtilis). Responses specific for proteins with a common localization as well as more general stress responses were observed. The latter include upregulation of genes encoding intracellular stress proteins (groES/EL, CtsR regulated genes). Specific responses include upregulation of the liaIHGFSR operon under Usp45 and TEM-1 beta-lactamase overproduction; cssRS, htrA and htrB under all secreted proteins overproduction; sigW and SigW-regulated genes mainly under membrane proteins overproduction; and ykrL (encoding an HtpX homologue) specifically under membrane proteins overproduction. Conclusions. The results give better insights into B. subtilis responses to protein overproduction stress and provide potential targets for genetic engineering in order to further improve B. subtilis as a protein production host.
Project description:Our study showed that optimizing ncRNA expression can increase or lower the yield of alpha-amylase enzyme production in Bacillus subtilis while revealing a range of potentially novel ncRNAs.
Project description:Background. Bacillus subtilis is a favorable host for the production of industrially relevant proteins because of its capacity of secreting proteins into the medium to high levels, its GRAS (Generally Recognized As Safe) status, its genetic accessibility and its capacity to grow in large fermentations. However, production of heterologous proteins still faces limitations. Results. This study aimed at the identification of bottlenecks in secretory protein production by analyzing the response of B. subtilis at the transcriptome level to overproduction of eight secretory proteins of endogenous and heterologous origin and with different subcellular or extracellular destination: secreted proteins (NprE and XynA of B. subtilis, Usp45 of Lactococcus lactis, TEM-1beta -lactamase of Escherichia coli), membrane proteins (LmrA of L. lactis and XylP of Lactobacillus pentosus) and lipoproteins (MntA and YcdH of B. subtilis). Responses specific for proteins with a common localization as well as more general stress responses were observed. The latter include upregulation of genes encoding intracellular stress proteins (groES/EL, CtsR regulated genes). Specific responses include upregulation of the liaIHGFSR operon under Usp45 and TEM-1 beta-lactamase overproduction; cssRS, htrA and htrB under all secreted proteins overproduction; sigW and SigW-regulated genes mainly under membrane proteins overproduction; and ykrL (encoding an HtpX homologue) specifically under membrane proteins overproduction. Conclusions. The results give better insights into B. subtilis responses to protein overproduction stress and provide potential targets for genetic engineering in order to further improve B. subtilis as a protein production host. Samples for transcriptome analyses were induced at the exponential-growth phase (OD600 = 0.7) with 0.1% subtilin (subtilin containing supernatant of subtilin producing B. subtilis strain ATCC 6633). Cells were harvested 30 min after induction. Three or four independent cultures of each strain (target strains and controls) were used, and cells were sampled for microarray experiment.