A Review <i>Escherichia coli</i> and the Human Gut: Some Ecological Considerations

Mason, Tony; Richardson, George Maxwell

doi:10.1111/j.1365-2672.1981.tb00903.x

Cited by 51 publications

(25 citation statements)

References 104 publications

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“…the traits crucial for successful competition against other bacterial species, are those found in all strains and not those that are variable (Mason & Richardson, 1981). In this study, a very low level of intraspecies genomic variation in phosphotransferase systems and dissimilatory enzymes for sugars and sugar alcohols was found (Tables 3 and 4).…”

Section: Discussionmentioning

confidence: 76%

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Comparative genomic hybridization and physiological characterization of environmental isolates indicate that significant (eco-)physiological properties are highly conserved in the species Escherichia coli

et al. 2007

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Section: Discussionmentioning

confidence: 76%

“…The primary habitat of E. coli, the colon, is a complex ecosystem with a high diversity of bacterial species, which can coexist presumably due to the diversity of growth substrates entering it (Mason & Richardson, 1981). However, still very little is known about the nutritional preferences of gut bacteria (Peekhaus & Conway, 1998).…”

Section: Discussionmentioning

confidence: 99%

Comparative genomic hybridization and physiological characterization of environmental isolates indicate that significant (eco-)physiological properties are highly conserved in the species Escherichia coli

et al. 2007

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“…The efficient recycling of components such as membrane lipids and proteins is of great importance for survival of microorganisms living in natural habitats (3,23,25,39). A metabolic pathway for ethanolamine utilization might therefore be an important survival strategy against the constant famine that microorganisms face in nature, although so far there is no experimental evidence to support this hypothesis (13,24). In addition, ethanolamine found in the mammalian gastrointestinal tract may present an important alternative source of nitrogen and carbon for bacteria living in the gut.…”

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confidence: 99%

Ethanolamine utilization in Salmonella typhimurium: nucleotide sequence, protein expression, and mutational analysis of the cchA cchB eutE eutJ eutG eutH gene cluster

1995

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A fragment of the Salmonella typhimurium ethanolamine utilization operon was cloned and characterized. The 6.3-kb nucleotide sequence encoded six complete open reading frames, termed cchA, cchB, eutE, eutJ, eutG, and eutH. In addition, the nucleotide sequences of two incomplete open reading frames, termed eutX and eutI, were also determined. Comparison of the deduced amino acid sequences and entries in the GenBank database indicated that eutI encodes a phosphate acetyltransferase-like enzyme. The deduced amino acid sequences of the EutE and EutG proteins revealed a significant degree of homology with the Escherichia coli alcohol dehydrogenase AdhE sequence. Mutations in eutE or eutG completely abolished the ability of mutants to utilize ethanolamine as a carbon source and reduced the ability to utilize ethanolamine as a nitrogen source. The product of eutE is most probably an acetaldehyde dehydrogenase catalyzing the conversion of acetaldehyde into acetyl coenzyme A. The product of the eutG gene, an uncommon iron-containing alcohol dehydrogenase, may protect the cell from unconverted acetaldehyde by converting it into an alcohol. The deduced amino acid sequence of cchA resembles that of carboxysome shell proteins from Thiobacillus neapolitanus and Synechococcus sp. as well as that of the PduA product from S. typhimurium. CchA and CchB proteins may be involved in the formation of an intracellular microcompartment responsible for the metabolism of ethanolamine. The hydrophobic protein encoded by the eutH gene possesses some characteristics of bacterial permeases and might therefore be involved in the transport of ethanolamine. Ethanolamine-utilization mutants were slightly attenuated in a mouse model of S. typhimurium infection, indicating that ethanolamine may be an important source of nitrogen and carbon for S. typhimurium in vivo.Ethanolamine is, in the form of phosphatidylethanolamine, an essential component of both prokaryotic and eukaryotic membranes (32). The efficient recycling of components such as membrane lipids and proteins is of great importance for survival of microorganisms living in natural habitats (3,23,25,39). A metabolic pathway for ethanolamine utilization might therefore be an important survival strategy against the constant famine that microorganisms face in nature, although so far there is no experimental evidence to support this hypothesis (13,24). In addition, ethanolamine found in the mammalian gastrointestinal tract may present an important alternative source of nitrogen and carbon for bacteria living in the gut. Therefore, it should not be surprising that many enterobacteria, including Escherichia coli and Salmonella typhimurium, can use ethanolamine as a source of both carbon and nitrogen (5, 43). Roof and Roth isolated a large number of S. typhimurium mutants which were deficient in different stages of ethanolamine utilization (36). An elegant genetic analysis of these mutants revealed six complementation groups in the ethanolamine utilization operon located at 50 min on the S. typhi...

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“…Although growth without oxygen can occur by anaerobic respiration, in its natural habitat, the mammalian intestine, E. coli depends largely on fermenting a mixture of sugars and sugar derivatives (Peekhaus & Conway, 1998 ;Mason & Richardson, 1981). During fermentation, sugars are converted to reduced organic compounds such as ethanol and acetic, lactic, formic and succinic acids ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Regulation of the ldhA gene, encoding the fermentative lactate dehydrogenase of Escherichia coli

2001

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The fermentative lactate dehydrogenase (LDH) of Escherichia coli is induced by low pH under anaerobic conditions. Both translational and transcriptional gene fusions to ldhA, which encodes the fermentative LDH, have now been made. Both types of ldhA-lacZ fusion were induced by low pH, but only in the absence of air. However, the translational fusions were consistently expressed at a five-to tenfold higher level than the transcriptional fusions, perhaps implying some post-transcriptional effect on ldhA expression. Introduction of arcB ::Kan decreased expression of both translational and transcriptional ldhA-lacZ fusions by three-to fivefold. Disruption of mlc, which encodes a repressor of several genes of the phosphotransferase system, almost abolished expression of ldhA. Disruption of csrA caused a moderate drop in expression of both operon and protein ldhA fusions, whereas insertional inactivation of csrB or glgA had the opposite effect. These effects are probably indirect, resulting from alterations in sugar accumulation versus storage. Mutations in ptsG, cra, fnr, narL, rpoS, osmZ, appY, ack/pta, aceEF, pfl and ldhA had no effect on expression of the ldhA fusions. ldhA was not induced by the membranepermeant weak acid benzoate, implying that it does not respond to the internal pH directly. Little pH induction was seen during growth on glycerol plus fumarate, suggesting that products of sugar fermentation are necessary for acid induction. Addition of succinate, acetate or lactate had no effect on ldhA expression. In contrast, pyruvate caused a two-to fourfold increase in expression of ldhA-lacZ. This accords with the idea that increased sugar metabolism indirectly induces ldhA.

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A Review Escherichia coli and the Human Gut: Some Ecological Considerations

Cited by 51 publications

References 104 publications

Comparative genomic hybridization and physiological characterization of environmental isolates indicate that significant (eco-)physiological properties are highly conserved in the species Escherichia coli

Comparative genomic hybridization and physiological characterization of environmental isolates indicate that significant (eco-)physiological properties are highly conserved in the species Escherichia coli

Ethanolamine utilization in Salmonella typhimurium: nucleotide sequence, protein expression, and mutational analysis of the cchA cchB eutE eutJ eutG eutH gene cluster

Regulation of the ldhA gene, encoding the fermentative lactate dehydrogenase of Escherichia coli

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