Eubacterium isolation

Rafii F, Smith DB, Benson RW, Cemiglia CE (1992) Immunological homology among azoreductases from Clostridium and Eubacterium strains isolated from human intestinal microflora. J Basic Microbiol 32 99-105... 

Another selenium-containing molybdenum hydroxylase that has been isolated from Clostridium barkeri (identical to Eubacterium barkeri) is nicotinic acid hydroxylase (NAH). Clostridium barkeri was isolated initially as a fermentor of nicotinic acid and thus NAH is a key enzyme in the efficient fermentation of nicotinic acid as a source of carbon and energy. NAH contained selenium when purified from cells labeled with Se-selenite. However, this label was lost during denaturing gel electrophoresis and also on heating of the enzyme (Dilworth 1982). Exhaustive analysis of selenium-labeled alkylation products of NAH under various conditions revealed selenium was bound as a labile cofactor (Dilworth 1982), and not as seleno-cysteine. This report was the first to describe a selenium-dependent enzyme that did not contain selenium in the form of selenocysteine. 

FDHs were isolated from another type of anaerobic bacterium (Eubacterium acidacminophilum) FDHs catalyze the reversible reduction of CO2 to formate (Table 2), with the concomitant transfer of two electrons from the appropriate electron carrier. This reaction has a very negative reduction potential (-420 mV, SHE). The syntrophic bacterium Syntrophobacter fumaroxidans constitutively expressed two W-containing FDH s (FDH-1 and FDH-2) when grown on fumarate or propionate. The purified enzymes exhibit high formate-oxidation and CO2-reduction rates and very low Km values for formate. 

Intestinal bacteria capable of 7a-dehydroxylating bile acids have been isolated by several laboratories [16,50]. Most intestinal bacteria that carry out 7-dehydroxylation have been identified as members of the genera Clostridium [50-52] or Eubacterium [51,53]. Stellwag and Hylemon [52] and Ferrari et al. [54] demonstrated that the fecal population of 7 -dehydroxylating intestinal bacterial in man and rats is in the range of 10 -10 viable organisms/g wet weight feces. 

The inducible arsenite oxidase from the Eubacterium Alcaligenes faecalis (NCIB 8687) has been purified and characterized (22-24). Anderson et al. (24) isolated the enzyme from a sonicate of washed, lysozyme-treated cells that had been harvested in their late exponential growth phase. The sonicate was fractionated by gel filtration through DEAE-sepharose and active fractions concentrated by ultrafiltration. The purified enzyme was found to be monomeric with a molecular mass of 85 kDa. It consisted of two polypeptide chains in an approximate ratio of 70 30. The enzyme stmcture included one molybdenum, five or six iron atoms, and sulfide. Purification of the oxidase also led to recovery of azurin, a blue protein, which was rapidly reduced by arsenite in the presence of catalytic amounts of Aro, and a red protein. The red protein was a c-type cytochrome, which was reduced by arsenite in the presence of catalytic amounts of Aro and azurin. No reduction of the cytochrome occurred in the absence of Aro, but it did occur in the absence of azurin. Denaturation of Aro led to the release of a pterin cofactor characteristic of molybdenum hydroxylases. In intact cells of A. faecalis, the enzyme resides on the outer surface of the inner (plasma) membrane. The cytochrome and azurin may be part of an electron transfer pathway in the periplasm. 

New type of biopolymer, not strictly a polysaccharide. Isol. from Eubacterium saburreum strain LI 3. 

Chang, I.S., et al., 1997. Isolation and identification of carbon monoxide utilizing anaerobe. Eubacterium limosum KIST612. Korean Journal of Applied Microbiology and Biotechnology 25 (1), 1—8. 

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