Bacterial metabolism, products

Ockels W, Rdmer A, Budzikiewicz H, Korth H, Pulverer G (1978) An Fe(II) Complex of Pyridine-2,6-di(monothiocarhoxylic acid) - a Novel Bacterial Metabolic Product. Tetrahedron Lett 3341... 

Slime layers are a mixture of bacterial secretions called extracellular polymers, other metabolic products, bacteria, gases, detritus, and water. Commonly, 99% of the slime layer is water, although much silt and debris may also become entrapped in it. 

Bacterial catabolism of oral food residue is probably responsible for a higher [NHj] in the oral cavity than in the rest of the respiratory tract.Ammonia, the by-product of oral bacterial protein catabolism and subsequent ureolysis, desorbs from the fluid lining the oral cavity to the airstream.. Saliva, gingival crevicular fluids, and dental plaque supply urea to oral bacteria and may themselves be sites of bacterial NH3 production, based on the presence of urease in each of these materials.Consequently, oral cavity fNTi3)4 is controlled by factors that influence bacterial protein catabolism and ureolysis. Such factors may include the pH of the surface lining fluid, bacterial nutrient sources (food residue on teeth or on buccal surfaces), saliva production, saliva pH, and the effects of oral surface temperature on bacterial metabolism and wall blood flow. The role of teeth, as structures that facilitate bacterial colonization and food entrapment, in augmenting [NH3J4 is unknown. 

The significance of pH is particularly interesting since pH may either augment or diminish NH3 production. The possible mechanisms by which pH affects NH3 production are (a) inhibition of bacterial metabolism, (b) pH-dependent changes in urea metabolic pathways, (c) pH-dependent bacterial utilization of glucose and urea as energy sources, and (d) increased bacterial uti-... 

The harvest is a very eomplex mixture of bacterial cells, metabolic products and exhausted medium. In the ease of a live attenuated vaccine it is innocuous and all that is necessary is for the baeteria to be separated and resuspended in an appropriate menstmum, possibly for freeze-drying. In a vaccine made Irom a pathogen the harvest may be intensely dangerous and great care is necessary in the following procedures. 

Bacterial corrosion is often referred to as microbiologically influenced corrosion. MIC involves the initiation or acceleration of corrosion by microorganisms. The metabolic products of microorganisms appear to affect most engineering materials, but the more commonly used corrosion-resistant alloys, such as stainless steels, seem to be particularly susceptible. 

Weak acids are products of bacterial metabolisms. Sulfate-reducing bacteria regulate the pH of their environment at levels that depend on the potential... 

Polysaccharide formation may be endocellular, exocellular or capsular. The polysaccharide is usually a normal metabolic product, frequently a major product. Isolation and purification of a bacterial polysaccharide generally involve continued precipitations from a buffered solution, together with electrodialysis or ultrafiltration. 

Although polysaccharide metabolic products of molds and yeasts are not strictly bacterial polysaccharides, they are considered briefly here because of similarities in chemical structure (see also page 191). 

At least one of the organolead compounds has been shown to be a normal constituent of the aqueous environment. Tetramethyl lead has been found as a product of anaerobic bacterial metabolism in lake sediments [23]. It should perhaps be sought in the air over coastal mud flats. 

Kaiser, K.L. and Wong, P.T.S. Bacterial degradation of polychlorinated biphenyls. 1. Identification of some metabolic products fromAroclor 1242, Bull. Environ. Contam. Toxicol, ll(3) 291-296, 1974. 

In bacterial and mammalian in vitro cell systems TNT is a direct-acting mutagen. However, inclusion of exogenous metabolic activation appears to abolish the genotoxicity. In vivo assays of TNT have not shown it to be genotoxic, suggesting that TNT may be reduced to nonmutagenic metabolic products in the whole animal. 

Some of the pathways of animal and bacterial metabolism of aromatic amino acids also are used in plants. However, quantitatively more important are the reactions of the phenylpropanoid pathway,173-1743 which is initiated by phenylalanine ammonia-lyase (Eq. 14-45).175 As is shown at the top of Fig. 25-8, the initial product from phenylalanine is trails-cinnam-ate. After hydroxylation to 4-hydroxycinnamate (p-coumarate) and conversion to a coenzyme A ester,1753 the resulting p-coumaryl-CoA is converted into mono-, di-, and trihydroxy derivatives including anthocyanins (Box 21-E) and other flavonoid compounds.176 The dihydroxy and trihydroxy methylated products are the starting materials for formation of lignins and for a large series of other plant products, many of which impart characteristic fragrances. Some of these are illustrated in Fig. 25-8. 

Two bacterial strains, one from soil and the other from infected local beer, which utilised calarene as the sole source of carbon and energy have been isolated by enrichment culture techniques [149]. Both these bacteria were adapted to grow on valencene as the sole carbon source. Fermentations of valencene (5) by these bacteria of the genus Enterobacter in a mineral salts medium yielded several neutral metabolic products dihydro alpha-agarofuran (200) (7.5%), nootkatone (6) (12%), another ketone (201) (18%) and a-cyperone (202) (8%), Fig. (40). 

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