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  • American Society for Microbiology  (5)
  • Zhang, Lei  (5)
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  • American Society for Microbiology  (5)
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  • 1
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 196, No. 22 ( 2014-11-15), p. 3949-3963
    Abstract: Rex, a transcriptional repressor that modulates its DNA-binding activity in response to NADH/NAD + ratio, has recently been found to play a role in the solventogenic shift of Clostridium acetobutylicum . Here, we combined a comparative genomic reconstruction of Rex regulons in 11 diverse clostridial species with detailed experimental characterization of Rex-mediated regulation in C. acetobutylicum . The reconstructed Rex regulons in clostridia included the genes involved in fermentation, hydrogen production, the tricarboxylic acid cycle, NAD biosynthesis, nitrate and sulfite reduction, and CO 2 /CO fixation. The predicted Rex-binding sites in the genomes of Clostridium spp. were verified by in vitro binding assays with purified Rex protein. Novel members of the C. acetobutylicum Rex regulon were identified and experimentally validated by comparing the transcript levels between the wild-type and rex -inactivated mutant strains. Furthermore, the effects of exposure to methyl viologen or H 2 O 2 on intracellular NADH and NAD + concentrations, expression of Rex regulon genes, and physiology of the wild type and rex -inactivated mutant were comparatively analyzed. Our results indicate that Rex responds to NADH/NAD + ratio in vivo to regulate gene expression and modulates fermentation product formation and oxidative stress tolerance in C. acetobutylicum . It is suggested that Rex plays an important role in maintaining NADH/NAD + homeostasis in clostridia.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2014
    detail.hit.zdb_id: 1481988-0
    SSG: 12
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  • 2
    In: Microbiology Spectrum, American Society for Microbiology, Vol. 10, No. 5 ( 2022-10-26)
    Abstract: Studies have confirmed that insomnia is related to gut microbiota. Previous research suggests that immunity and metabolism are also associated with insomnia. However, to our knowledge, the integration of these factors has not been investigated in insomnia. Here, we explored the correlations across gut microbiota, serum metabolism, and inflammatory factors in insomnia. Our results showed that the composition and structure of gut microbiota and metabolism in insomnia patients were different from healthy controls. Compared to healthy controls, the relative abundances of Lactobacillus , Streptococcus , and Lactobacillus crispatus were significantly increased in insomniacs. There were five metabolic pathways in insomniacs (glycerophospholipid metabolism; glutathione metabolism; nitrogen metabolism; alanine, aspartate, and glutamate metabolism; aminoacyl-tRNA biosynthesis) significantly different between the two groups. Moreover, we found that IL-1β levels were significantly higher in insomnia patients while TNF-α was significantly reduced. We further identified that the changes in the level of IL-1β and TNF-α were associated with some specific bacteria and metabolites, such as Prevotella amnii , Prevotella buccalis , Prevotella timonensis , and Prevotella colorans . Mediation analysis further determined that the immune factors and metabolites could mediate the relationship between gut microbes and insomnia. IMPORTANCE Our study indicated that systematic inflammation and metabolites might be a pathway linking the gut microbiome with insomnia. These findings provide new insights and a better understanding of gut microbiota's role in insomnia as well as potential novel microbiome-related etiologies for insomnia.
    Type of Medium: Online Resource
    ISSN: 2165-0497
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2022
    detail.hit.zdb_id: 2807133-5
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  • 3
    Online Resource
    Online Resource
    American Society for Microbiology ; 2023
    In:  Microbiology Spectrum Vol. 11, No. 2 ( 2023-04-13)
    In: Microbiology Spectrum, American Society for Microbiology, Vol. 11, No. 2 ( 2023-04-13)
    Abstract: Microbiota can influence the occurrence, development, and therapeutic response of a wide variety of cancer types by modulating immune responses to tumors. Recent studies have demonstrated the existence of intratumor bacteria inside ovarian cancer (OV). However, whether intratumor microbes are associated with tumor microenvironment (TME) and prognosis of OV still remains unknown. The RNA-sequencing data and clinical and survival data of 373 patients with OV in The Cancer Genome Atlas (TCGA) were collected and downloaded. According to the knowledge-based functional gene expression signatures (Fges), OV was classified into two subtypes, termed immune-enriched and immune-deficient subtypes. The immune-enriched subtype, which had higher immune infiltration enriched with CD8 + T cells and the M1 type of macrophages (M1) and higher tumor mutational burden, exhibited a better prognosis. Based on the Kraken2 pipeline, the microbiome profiles were explored and found to be significantly different between the two subtypes. A prediction model consisting of 32 microbial signatures was constructed using the Cox proportional-hazard model and showed great prognostic value for OV patients. The prognostic microbial signatures were strongly associated with the hosts’ immune factors. Especially, M1 was strongly associated with five species ( Achromobacter deleyi and Microcella alkaliphila , Devosia sp. strain LEGU1, Ancylobacter pratisalsi , and Acinetobacter seifertii ). Cell experiments demonstrated that Acinetobacter seifertii can inhibit macrophage migration. Our study demonstrated that OV could be classified into immune-enriched and immune-deficient subtypes and that the intratumoral microbiota profiles were different between the two subtypes. Furthermore, the intratumoral microbiome was closely associated with the tumor immune microenvironment and OV prognosis. IMPORTANCE Recent studies have demonstrated the existence of intratumoral microorganisms. However, the role of intratumoral microbes in the development of ovarian cancer and their interaction with the tumor microenvironment are largely unknown. Our study demonstrated that OV could be classified into immune-enriched and -deficient subtypes and that the immune enrichment subtype had a better prognosis. Microbiome analysis showed that intratumor microbiota profiles were different between the two subtypes. Furthermore, the intratumor microbiome was an independent predictor of OV prognosis that could interact with immune gene expression. Especially, M1 was closely associated with intratumoral microbes, and Acinetobacter seifertii could inhibit macrophage migration. Together, the findings of our study highlight the important roles of intratumoral microbes in the TME and prognosis of OV, paving the way for further investigation into its underlying mechanisms.
    Type of Medium: Online Resource
    ISSN: 2165-0497
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2023
    detail.hit.zdb_id: 2807133-5
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  • 4
    In: Microbiology Spectrum, American Society for Microbiology, Vol. 11, No. 4 ( 2023-08-17)
    Abstract: The induction of aberrant DNA methylation is the major pathway by which Helicobacter pylori infection induces stomach adenocarcinoma (STAD). The involvement of the non- H. pylori gastric microbiota in this mechanism remains to be examined. RNA sequencing data, clinical information, and DNA methylation data were obtained from The Cancer Genome Atlas (TCGA) STAD project. The Kraken 2 pipeline was employed to explore the microbiome profiles. The microbiome was associated with occurrence, distal metastasis, and prognosis, and differential methylation changes related to distal metastasis and prognosis were analyzed. Bi-directional mediation effects of the intratumoral microbiome and host DNA methylation changes on the metastasis and prognosis of STAD were identified by mediation analysis. The expression of the ZNF215 gene was verified by real-time quantitative PCR (RT-qPCR). A cell counting kit 8 (CCK8) cell proliferation experiment and a cell clone formation experiment were used to evaluate the proliferation and invasion abilities of gastric cells. Our analysis revealed that H. pylori and other cancer-related microorganisms were related to the occurrence, progression, or prognosis of STAD. The related methylated genes were particularly enriched in related cancer pathways. Kytococcus sedentarius and Actinomyces oris , which interacted strongly with methylation changes in immune genes, were associated with prognosis. Cell experiments verified that Staphylococcus saccharolyticus could promote the proliferation and cloning of gastric cells by regulating the gene expression level of the ZNF215 gene. Our study suggested that the bi-directional mediation effect between intratumoral microorganisms and host epigenetics was key to the distal metastasis of cancer cells and survival deterioration in the tumor microenvironment of stomach tissues of patients with STAD. IMPORTANCE The burgeoning field of oncobiome research declared that members of the intratumoral microbiome besides Helicobacter pylori existed in tumor tissues and participated in the occurrence and development of gastric cancer, and the methylation of host DNA may be a potential target of microbes and their metabolites. Current research focuses mostly on species composition, but the functional genes of the members of the microbiota are also key to their interaction with the host. Therefore, we focused on characterizing the species composition and functional gene composition of microbes in gastric cancer, and we suggest that microbes may further participate in the occurrence and development of cancer by influencing abnormal epigenetic changes in the host. Some key bioinformatics analysis results were verified by in vitro experiments. Thus, we consider that the tumor microbiota-host epigenetic axis of gastric cancer microorganisms and the host explains the mechanism of the microbiota participating in cancer occurrence and development, and we make some verifiable experimental predictions.
    Type of Medium: Online Resource
    ISSN: 2165-0497
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2023
    detail.hit.zdb_id: 2807133-5
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  • 5
    Online Resource
    Online Resource
    American Society for Microbiology ; 2012
    In:  Journal of Bacteriology Vol. 194, No. 19 ( 2012-10), p. 5413-5422
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 194, No. 19 ( 2012-10), p. 5413-5422
    Abstract: Solvent-producing clostridia are capable of utilizing pentose sugars, including xylose and arabinose; however, little is known about how pentose sugars are catabolized through the metabolic pathways in clostridia. In this study, we identified the xylose catabolic pathways and quantified their fluxes in Clostridium acetobutylicum based on [1- 13 C]xylose labeling experiments. The phosphoketolase pathway was found to be active, which contributed up to 40% of the xylose catabolic flux in C. acetobutylicum . The split ratio of the phosphoketolase pathway to the pentose phosphate pathway was markedly increased when the xylose concentration in the culture medium was increased from 10 to 20 g liter −1 . To our knowledge, this is the first time that the in vivo activity of the phosphoketolase pathway in clostridia has been revealed. A phosphoketolase from C. acetobutylicum was purified and characterized, and its activity with xylulose-5-P was verified. The phosphoketolase was overexpressed in C. acetobutylicum , which resulted in slightly increased xylose consumption rates during the exponential growth phase and a high level of acetate accumulation.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 2012
    detail.hit.zdb_id: 1481988-0
    SSG: 12
    Location Call Number Limitation Availability
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