Unknown,Transcriptomics,Genomics,Proteomics

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Expression analysis of Bacteroides fragilis NCTC 9343 delta-ungD1 delta-ungD2 delta-PSH acapsular mutant

ABSTRACT: Investigation of whole genome gene expression level changes in a Bacteroides fragilis NCTC 9343 delta-ungD1 delta-ungD2 delta-PSH triple mutant, compared to the wild-type strain. The mutations engineered into this strain render it acapsular. The mutants analyzed in this study are further described in Coyne, M. J., M. Chatzidaki-Livanis, L. C. Paoletti, and L. E. Comstock. 2008. Role of glycan synthesis in colonization of the mammalian gut by the bacterial symbiont Bacteroides fragilis. PNAS 105(35):13098-13103 (PID 18723678). 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 triple mutant strain, Bacteroides fragilis NCTC 9343 delta-ungD1 delta-ungD2 delta-PSH, in which ungD1 (BF1706), ungD2 (BF2848), and six genes (BF3454 through BF3459) of the PSH capsular polysaccharide locus are truncated or deleted entirely. 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.

ORGANISM(S): Bacteroides fragilis NCTC 9343

SUBMITTER: Michael Coyne

PROVIDER: E-GEOD-11268 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Role of glycan synthesis in colonization of the mammalian gut by the bacterial symbiont Bacteroides fragilis.

Coyne Michael J MJ Chatzidaki-Livanis Maria M Paoletti Lawrence C LC Comstock Laurie E LE

Proceedings of the National Academy of Sciences of the United States of America 20080822 35

Bacteroides species are the most abundant Gram-negative bacteria of the human colonic microbiota. These endogenous organisms are unique in that they synthesize an extensive number of phase-variable surface polysaccharides. Pathogenic bacteria phase vary expression of surface molecules for immune evasion, but the importance of the synthesis of multiple phase-variable polysaccharides to these commensal bacteria is unknown. We previously showed that a Bacteroides fragilis mutant unable to synthesiz ...[more]

PMID: 18723678

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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).

Dataset Information

Expression analysis of Bacteroides fragilis NCTC 9343 delta-ungD1 delta-ungD2 delta-PSH acapsular mutant

Publications

Role of glycan synthesis in colonization of the mammalian gut by the bacterial symbiont Bacteroides fragilis.

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