Bacteria, lactic acid cell wall

Nagaoka, M., Hashimoto, S., Watanabe, T., et al. (1994) Anti-ulcer effects of lactic acid bacteria and their cell wall polysaccharides. Biol Pharm Bull 17, 1012-1017. 

The correlation between chemical composition of microorganisms and their susceptibility to sakacin P, a bacteriocin produced by some lactic acid bacteria, was carried out by Oust et al. [53], It could be shown that at least some of the variations in the susceptibility to sakacin P in Listeria monocytogenes can be correlated to alterations in the chemical composition of the bacterial cell wall. 

The approach of Casiot et al. [21] was soon accepted and followed in the held of Se speciation. Wrobel et al. [91] applied a bacterium (Arthrobacter luteus) derived lysing enzyme mixture added with PMSF to study the intermediary molecules of Se metabolism of Se-enriched yeast without proteolysis. In order to tailor the cell wall degrading mechanism to the samples under test, Michalke et al. [77] used bacterial lisozyme and pronase E, either alone or in combination, for the Se speciation of Se-enriched lactic acid bacteria. Independent and simultaneous experiments were carried out with the two enzymes, thus achieving outstanding total Se-extraction efficiency (85-105 percent) with the sole application of pronase E and relatively low chromatographic recovery (8-12 percent) (still... 

Lysozyme is an enzyme that can cause lysis of the cell walls of Gram-positive bacteria, including lactic acid bacteria in wine (Delfini 2004). Lysozyme maintains its activity in wines with high pH values so it can be used successfully to delay or inhibit the growth of lactic acid bacteria, especially when used together with SO2,... 

Bacteria contain polysaccharides in their cell walls in the form of peptidoglycans. In the case of Grampositive bacteria, the long polysaccharide chains are strictly alternating copolymers of N-acetylglucosamine (NAG) and N-acetylmuramic Acid (NAM). A tetrapeptide is attached to the lactic acid moiety of the NAM. 

Some commercial silage additives now contain enzymes along with an inoculum of suitable strains of lactic acid bacteria. The enzymes are usually cellulases and hemicellulases, which degrade the cell walls of plants, thus releasing sugars, which are then available for fermentation by the lactic acid bacteria. The enzymes appear to be most effective when added to young herbage ensiled at low dry matter content. 

Lactic acid bacteria synthesise a range of different polysaccharides, defined by their location in the cell. Some are located intracellularly and are used as energy or carbon sources others are cell wall components and some are located outside the cell wall. The latter are called extracellular polysaccharides (EPs) and are either associated with the cell wall as a slime capsule, or secreted into the environment. Many lactic acid bacteria such as Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermo-philus and Lactococcus lactis subsp. cremoris produce EPs. 

Gross proteolytic activity of lactic acid bacteria is the sum of proteinase and peptidase activity. Normally, proteinases are plasmid-encoded and the enzymes are, in most cases, associated with the cell wall by a calcium ion-dependent binding. The synthesis of proteinase seems to be regulated by the growth medium (Exterkate, 1985 Bruinenberg et al., 1992). Normally, milk as growth medium forces strains to produce a high level of proteinase. 

Studies of the effects of thermal stress on three strains of Staphylococcus aureus have indicated that the teichoic acid in the cell walls aids the survival of the cells by maintaining the accessible pool of Mg ions on the cell surface. A spore-forming Gram-negative bacterium with properties closely similar to those of Bacillus circulans, and which hydrolyses the 2-acetamido-2-deoxy-D-glucosylribitol teichoic acid from Staph, aureus, has been isolated from soil. The immunogenicities of teichoic and lipoteichoic acids from the cell walls and plasma membranes of several oral bacteria that produce lactic acid have been reported. 

Park and Johnson found that three uridine nucleotides accumulated in Staph, aureus treated with penicillinii . The major nucleotide (LVIII) was later shown to consist of uridine 5 -pyrophosphate (UDP) linked to a new N-acetylamino sugar that is linked in turn to a peptide. The new amino sugar occurs in the cell walls of a number of bacteria and has been named muramic acid. It is an ether of D-glucosamine and lactic acid (GNAc-lactic)... 

The cell walls of lactic acid bacteria, like those of nearly all Gram-positive bacteria, also contain... 

Fig. 4.1. Lactic acid bacteria isolated in wine under a scanning electron microscope (Departement de Microscopie Electronique, University of Bordeaux I), (a) Photograph of Lactobacillus plantarum cells (transmission, Lonvaud, 1975) c = cytoplasm pm = plasma membrane cw = cell wall s = septum m = mesosome n = nucleus, (b) Photograph of I uconostoc oenos Oenococcus oeni) (scanning electron microscope).

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