Abnormal intestinal flora.

S Tabaqchali

Home/Archive/PubMed

PubMed · 553481

Abnormal intestinal flora.

S Tabaqchali

View original source ↗Export metadata ↓

Abstract

The normal small intestine in man usually harbours a sparse microflora consisting of Gram-positive microorganisms derived from the oro-pharynx. The concentrations in the upper jejunum are approximately 10(3)-10(4) organisms/ml, whereas in the ileum the concentrations may be higher and faecal type organisms may also be present, such as Enterobacteria, Bifidobacteria, and Bacteroides in concentrations of 10(5)-10(6) organisms per ml of intestinal aspirate [24, 25]. This situation is well maintained unless the integrity of the small intestine is deranged. There are however, certain conditions in which bacterial proliferation in the lumen of the small intestine may occur and give rise to various metabolic abnormalities [2]. In this paper I would like to list some of these conditions, then describe the type of microflora which colonizes the small intestine, and finally discuss a few aspects of the metabolic consequences of these bacteria.

Explore related subjects

Actinomycetaceae Amino Acids Bacteria Bacteroides Bile Acids and Salts Enterobacteriaceae Gastric Juice Humans Intestinal Diseases Intestine, Small Vitamin B 12 Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

S Tabaqchali. 1979. Abnormal intestinal flora.. https://pubmed.ncbi.nlm.nih.gov/553481/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2026

Complete genome sequence of Actinomycetaceae bacterium strain MB13-C1-2, isolated from the feces of the black soldier fly larvae.

Here, we report the complete genome sequence of Actinomycetaceae bacterium strain MB13-C1-2, isolated from the feces of black soldier fly (Hermetia illucens) larvae, comprising 2,578,609 bp and a GC content of 57.23%. The genome was selected for further analyses of species delineation and genomic features.

Actinomycetaceae↗

PubMed1992

Self-protection mechanisms in antibiotic producers.

Various ways in which antibiotic-producing organisms are able to resist the actions of their products are discussed. Examples are given of antibiotic inactivation and also the modification of antibiotic target sites (most notably, ribosomes) to which drugs would otherwise bind and thereby exert their usual inhibitory effects. An interesting variation on the latter theme involves the duplication of target enzymes so that both sensitive and resistant versions are produced, the latter inducibly. Speculative discussion of antibiotic efflux leads to examples of cloned resistance determinants that probably encode components of efflux systems. Although of interest in their own right, resistance mechanisms should not be viewed narrowly when the physiology of antibiotic producers is considered. Thus, chemical modification of drug molecules may not only fulfil a protective role within the cell but may also provide substrates for efflux. Recent evidence that such considerations apply to macrolide antibiotics is presented. The control of resistance in producing organisms is also discussed with particular reference to the induction of novobiocin resistance in Streptomyces sphaeroides. This involves the interplay of novobiocin-sensitive and -resistant forms of DNA gyrase and features a promoter that displays a dramatic response to changes in DNA topology.

Actinomycetaceae↗

PubMed1992

Genes for polyketide secondary metabolic pathways in microorganisms and plants.

Recent advances in molecular genetics have led to the isolation, sequencing and functional analysis of genes encoding synthases that catalyse the formation of several classes of polyketides. The structures of the genes and their protein products differ strikingly in the various examples. For Streptomyces aromatic polyketides, exemplified by granaticin and tetracenomycin, the synthases correspond to Type II (bacterial and plant) fatty acid synthases in consisting of distinct proteins for such processes as condensation, acyl carrier function and ketoreduction. In contrast, for actinomycete macrolides such as erythromycin, similar catalytic functions are performed by a set of multifunctional proteins resembling Type I (animal) fatty acid synthases, but with every step in chain-building being catalysed by a different enzymic domain. Penicillium patulum has a simple Type I synthase for 6-methylsalicylic acid. For plant chalcones and stilbenes, a single small polypeptide acts as a condensing enzyme for carbon chain-building and may be unrelated to any of the other polyketide and fatty acid synthases. Thus, although these systems share a common general mechanism of chain assembly, they must differ in the ways that synthase 'programming' has evolved to determine chain length, choice of chain starter and extender units, and handling of successive keto groups during chain assembly, and so control the great diversity of possible chemical products.

Actinomycetaceae↗