Streptococcus faecalis mechanism

Gingell R, Walker R (1971) Mechanisms of azo reduction by Streptococcus faecalis II The role of soluble flavins. Xenobiotica 1 231... 

Pandey, V.N. Pradhan, D.S. Reverse and forward reactions of carbamyl phosphokinase from Streptococcus faecalis R. Participation of nucleotides and reaction mechanisms. Biochim. Biophys. Acta, 660, 284-292 (1981)... 

Prokaryotic organisms have developed a number of transport mechanisms for the extrusion of sodium ions against a concentration gradient. In Escherichia coli sodium efflux is linked to proton uptake and is independent of internal ATP, i.e. the cell uses a sodium/proton antiporter.70,71 In contrast in Streptococcus faecalis,72 sodium efflux involves an ATP-driven sodium-translocating ATPase, while in Halobacterium halobium the protein halorhodopsin has been postulated to catalyze the coupling of Na+ extrusion to light.73... 

Microbial cells maintain low internal [Ca2+] levels through the operation of several types of highly active and specific efflux processes.180,184 Efflux of Ca2+ can only be studied with difficulty in whole cells, partly because of complications resulting from the binding of Ca2+ to the cell walls. Nevertheless, the presence of active mechanisms for the efflux of calcium are shown by the fact that extreme temperatures or inhibitors result in increased levels of intracellular calcium. Efflux of Ca2+ has been demonstrated for B. megaterium, while ATP-linked efflux of Ca2+ has been demonstrated for Streptococcus faecalis.lss... 

Decarboxylation of amino acids is a typical feature of the bacterial decomposition of proteins. Both phenylethylamine and tyramine were isolated from putrid meat by Barger and Walpole (30), who considered it extremely probable that they were derived from phenylalanine and tyrosine, respectively. No cell-free preparation of phenylalanine decarboxylase appears to have been reported, but decarboxylation by a crude Streptococcus faecalis preparation provides a valuable method of phenylalanine assay (887). Bacterial tyrosine decarboxylase has been studied in detail (495), especially by Gale and co-workers (summarized in 284). It requires pyridoxal phosphate as coenzyme (26, 326, 327) and, unlike mammalian tyrosine decarboxylase, also attacks dihydroxyphenylalanine. Decarboxylation normally only occurs in acid media and is considered primarily to be a protective mechanism tending to restore the pH to neu-... 

Obviously, the elucidation of the enzymic mechanism required the preliminary purification of at least one of the transaminases. An 85-90% pure glutamic aspartic transaminase was obtained and found to contain 2 moles of pyridoxal phosphate per mole of enzyme. But pyridoxal is not the active coenzyme. Gunsalus, Bellamy, and Umbreit discovered that the addition of pyridoxal to a culture medium of a strain of Streptococcus faecalis grown on a pyri-doxal-deficient medium has little effect on the ability of the bacteria to decarboxylate tyrosine. When the culture was supplemented with pyridoxal and adenosine triphosphate, or with phosphorylated derivatives of pyridoxal, the tyrosine decarboxylation activity was greatly enhanced. It was later established that... 

Data from labelling experiments with the disaccharide-peptide monomers and peptide-cross-linked dimers and trimers found in the peptidoglycan of Streptococcus faecalis have shown that the peptide chains of peptidoglycans are cross-linked into dimers and trimers, etc., by a monomer-addition mechanism rather than by random cross-linking. Similarly, the in vitro synthesis of a peptide trimer by the extracellular transpeptidase of Streptomyces R61 is not a random process. Synthesis occurs preferentially by transpeptidation between a peptide monomer, acting as a donor, and a preformed peptide dimer, acting as an acceptor. 

While many natural products have been tested against hundreds of different strains of bacteria, the most common bacteria used in susceptibility tests include Bacillus cereus, Bacillus subtillis, Chlamydia pneumonia, Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pneumoniae, Klebsiella pneumoniae, vancomycin-resistant Enterococcus (VRE), Pseudomonas aeruginosa and Helicobacter pylori [18, 19], As the amount of published data describing the in vitro, in vivo and clinical antibacterial activities of natural products is so vast it could easily fill a book (or two), this review focuses only on natural products for which there is in vitro, in vivo and some clinical antibacterial data, as well as a plausible mechanism of action. 

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