Bacteroides thetaiotaomicron
| Bacteroides thetaiotaomicron | ||||||||||||
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| Scientific name | ||||||||||||
| Bacteroides thetaiotamicron | ||||||||||||
| ( Distaso 1912) Castellani & Chalmers 1919 |
Bacteroides thetaiotamicron is a bacteria art from the genus Bacteroides and as all species in this genus Gram negative , obligately anaerobic and non- spore forming .
properties
Bacteroides thetaiotamicron is a gram-negative and anaerobic bacterium that dominates the intestinal flora of most mammals. The proteins encoded by the genome enable the uptake of otherwise indigestible polysaccharides and their hydrolysis. At the same time, it provides the host with metabolic abilities that the host's genome does not allow. The glycosyl hydrolases and carbohydrate-binding proteins on the cell surface or in the periplasm of the outer cell membrane lead to the ability to react to external signals from the environment through signal transduction, which gives it an advantage over other organisms in the intestinal flora that do not have this ability. Furthermore, the bacterium is able to stimulate angiogenesis in the host organism during the postnatal development of the intestine and thus improve its ability to absorb nutrients. By manipulating the gene expression in the host, it is able, for example, to influence the synthesis of various glycans of the intestinal epithelium, including those which have a terminally alpha-linked fucose and can thus be harvested by its own alpha-fucosidases. However, this only happens if B. thetaiotaomicron perceives an insufficient fucose level in its environment and thus has to ensure its own survival. The presence of nutrients induced in this way is also used by other organisms, whereby all intestinal bacteria must always protect themselves against the host's adaptive immune response by camouflage. In summary, these highly developed strategies of B. thetaiotaomicron consist in the perception of its local environment, the metabolism of polysaccharides and the manipulation of the host's gene expression, which lead to a mutually beneficial symbiosis.
Genome structure
Its 6.26 megabase genome codes for 4802 proteins that enable the bacterium to take up otherwise indigestible polysaccharides and hydrolyze them. Of the 4802 predicted proteins, 58% presumably have functions that are based on homologies to other proteins, 18% have homologies to proteins of unknown function, while 23.4% have no identifiable homology to known proteins. The largest paralog groups are involved in the uptake and digestion of polysaccharides (e.g. amylose, amylopectin and pullulan), for example in the form of glycosyl hydrolases and carbohydrate-binding proteins on the cell surface. The presence of extracellular functional sigma factors in gene clusters, which code for glycosyl hydrolases and other sugar-digesting enzymes, suggests that these are regulated depending on physiological stimuli from the environment.
Role as a pathogen
Bacteroides thetaiotaomicron is the second most common infectious anaerobic gram-negative bacterium [3]. B. thetaiotaomicron is an opportunistic pathogen that is often associated with peritonitis, sepsis, and wound infections. B. thetaiotaomicron can cause very serious infections such as: B. intra-abdominal sepsis and bacteremia. Due to its resistance to antimicrobial substances, it is of great importance to identify and combat B. thetaiotaomicron in clinical samples.
Spread
Bacteroides thetaiotaomicron belongs to the normal human bacterial flora and even dominates it. So it is not a typical environmental germ.
Individual evidence
http://microbewiki.kenyon.edu/index.php/Bacteroides_thetaiotaomicron
- J. Xu, MK Bjursell, J. Himrod, S. Deng, LK Carmichael et al .: A Genomic View of the Human-Bacteroides thetaiotaomicron Symbiosis. Science, 299: 2074-2076, 2003.
- L. Comstock, M. Coyne: Bacteroides thetaiotaomicron: a dynamic, niche-adapted human symbiont. BioEssays, 25: 926-929, 2003.
[3] http://jcm.asm.org/content/42/4/1727.full?view=long&pmid=15071033