Project description:Genome expression study of Bacteroides fragilis strain 638R comparing a EcfO/anti-EcfO null mutant with an empty vector to a EcfO/anti-EcfO null mutant containing the EcfO gene on a plasmid under the control of a maltose inducible promoter. Two chip study with 8 technical replicates on each chip comparing the EcfO overexpressing strain in a EcfO/anti-EcfO mutant to an empty vector control in the same mutant background.
Project description:Genome expression study of Bacteroides fragilis strain 638R comparing a EcfO null mutant with an empty vector to a anti-EcfO null mutant containing the EcfO gene on a plasmid under the control of an IPTG inducible promoter. Two chip study with 8 technical replicates on each chip comparing the EcfO overexpressing strain in an anti-EcfO mutant to an empty vector control in a EcfO null mutant.
Project description:Genome expression study of Bacteroides fragilis strain 638R comparing an ecfO null mutant with an empty vector to a reo (anti-ecfO) null mutant containing the ecfO gene on a plasmid under the control of an IPTG inducible promoter. Seven chip study with 8 technical replicates (i.e. Each probe replicated 8 times on the chip) on each chip comparing the ecfO overexpressing strain in a reo (anti-ecfO) mutant to an empty vector control in an ecfO null mutant.
Project description:Genome expression study of Bacteroides fragilis ATCC25285 strain containing the EcfO gene constitutively expressed from plasmid pFD340 Two chip study with 5 technical replicates on each chip comparing the EcfO overexpressing strain to an empty vector control in the wild type strain.
Project description:The phylum Bacteroidetes is a major component of the human gut microbiota which has a broad impact on the development and physiology of its host, and a potential role in a wide range of disease syndromes1-3. The predominance of Bacteroidetes and the genus Bacteroides in the distal gut is due in large part to the expansion of paralogous gene clusters, termed Polysaccharide Utilization Loci (PULs), dedicated to the uptake and catabolism of host derived and dietary polysaccharides4,5. It is generally thought that the diversity of PULs is key to Bacteroides successful competition for nutrients in the gut environment6. The nutritive value of the available polysaccharides varies greatly and thus their utilization is hierarchical and strictly controlled. A typical PUL includes regulatory genes that control expression in response to the presence of specific glycan substrates. However the existence of additional regulatory mechanisms has been predicted to explain phenomena such as the hierarchical control, catabolite repression, and the fine tuning of gene expression to match catabolic activity7-9. Using Bacteroides fragilis as a model organism, this report describes a previously unknown layer of regulatory control in which cis-encoded antisense small RNAs (sRNA) act as repressors of the PULsâ catabolic genes. Nearly 30% of B. fragilis PULs are subject to this type of sRNA control and these PULs tend to be more closely linked to the utilization of host-derived glycans than dietary polysaccharides. The findings described here indicate the presence of a global control mechanism that underlies the known regulatory circuits which modulate PUL expression in response to substrate availability, and hence provide novel insight into regulation of the gut Bacteroidetes physiology. This is a 4 chip study with 8 technical replicates on each chip. This was an in vitro, exploratory study to determine if mutation or overexpression of a sRNA associated with the Don locus would affect gene expression. In vitro cultures were grown in defined media with mucin glycans as the sole carbon source. The two chips representing growth of the wild type strain (638R) on mucin glycans were also used in a related study GSE53883 (GSM1303101 and GSM1303102).
Project description:Compare BF638R gene expression during growth in vivo in a rat tissue cage/artificial abscess model, to cells grown in vitro in minimal defined media with either glucose or mucin glycans as sole carbon/energy source 11 chip study with 8 technical replicates on each chip comparing gene expression in vivo in a rat tissue cage model over an 8 day period to in vitro cultures grown to mid-log phase in defined media
Project description:Mapping the occupancy of FNR, HNS, and IHF throughout the genome of Escherchia coli MG1655 K-12 using an affinity purified antibody under anerobic growth conditions. We also mapped the binding of the M-CM-^_ subunit of RNA Polymerase under both aerobic and anaerobic growth conditions. As a control, we also performed ChIP-chip on FNR in a M-bM-^HM-^Ffnr mutant strain of Escherchia coli MG1655 K-12. We also examined FNR immunoprecipitation at various FNR concentrations using IPTG and Ptac::fnr (PK8263). The M-bM-^HM-^Fhns/M-bM-^HM-^FstpA strains were also used. Descirbed in the manuscript Genome-scale Analysis of E. coli FNR Reveals the Complexity of Bacterial Regulon Structure Mapping of occupancy of FNR, NNS, IHF and M-CM-^_ of RNAP in the genome of Escherchia coli MG1655 K-12 under aerobic or anaerobic growth conditions. Immunoprecipitated DNA compared to INPUT for each sample.
Project description:Degradation of complex dietary fibers by gut microbes is essential for colonic fermentation, short-chain fatty acid production, and microbiome function. Ruminococcus bromii is the primary resistant starch (RS) degrader in humans, which relies on the amylosome, a specialized cell-bound enzymatic complex. To unravel its structure-function relationship and the interplay among its components, we applied an holistic multilayered approach and found that amylosome combinatorics, resistant starch degradation and enzymatic synergy are regulated at two levels: structural constraints enforcing enzyme proximity and expression-driven shifts in enzyme proportions. Cryo-electron tomography revealed that the amylosome comprises a constitutive extracellular layer extending toward the RS. However, proteomics demonstrated its remodeling across different growth conditions, with Amy4 and Amy16 comprising 60% of the amylosome in response to RS. Structural and biochemical analyses revealed complementarity and synergistic RS degradation by these enzymes, which allow R. bromii to fine-tune its adaptation to dietary fiber and shape colonic metabolism
Project description:In Escherichia coli, the highly conserved enzymes MiaA and MiaB mediate the sequential prenylation and methylthiolation of adenosine-37 within tRNAs that decode UNN codons. We found that MiaA, but not MiaB, is critical to the fitness and virulence of extraintestinal pathogenic E. coli (ExPEC), a major cause of urinary tract and bloodstream infections. Deletion of miaA has pleiotropic effects, attenuating bacterial fitness and virulence within diverse host environments and rendering ExPEC especially sensitive to stressors like nitrogen and oxygen radicals and osmotic shock. We find that stress can stimulate striking changes in miaA expression. To assess how changing MiaA levels affect the pathogen proteome, we used MS to analyze the proteins express by the reference ExPEC isolate UTI89 and derivatives that either lack or overexpress MiaA.