Project description:Genome expression study of Bacteroides fragilis ATCC25285 strain containing the EcfO gene constitutively expressed from plasmid pFD340
Project description:Investigation of whole genome gene expression level changes in a Bacteroides fragilis NCTC 9343 delta-gmd-fcl delta-fkp mutant strain and a Bacteroides fragilis NCTC 9343 delta-lfg mutant strain, each as compared to the wild-type strain. The mutations engineered into these strains interfere with B. fragilis protein glycosylation.
Project description:Investigation of whole genome gene expression level changes in a Bacteroides fragilis NCTC 9343 delta-ungD1 delta-ungD2 double mutant compared to the wild-type strain. Keywords: expression analysis A six chip study using total RNA recovered from three separate wild-type cultures of Bacteroides fragilis NCTC 9343 and three separate cultures of a double mutant strain, Bacteroides fragilis NCTC 9343 delta-ungD1 delta-ungD2, in which ungD1 (BF1706) and ungD2 (BF2848) are deleted. Each chip measures the expression level of 4,302 genes from Bacteroides fragilis NCTC 9343 and the associated plasmid pBF9343 with fourteen 24-mer probe pairs (PM/MM) per gene, with three-fold technical redundancy.
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 PULs’ 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.
