The chemical nature and distribution of the peptidoglycan in Myxococcus xanthus at various stages of the cellular life cycle were investigated. Vegetative cells and microcysts contained approximately 0.6% by weight of peptidoglycan. The overall composition of the peptidoglycan was similar in both cell types and was approximately 1 glutamic acid, 1 diaminopimelic acid, 1.7 alanine, 0.75 N-acetylglucosamine, and 0.75 N-acetylmuramic acid. (We have assumed that all the hexosamines are N-acetylated.) The sizes of the subunits (estimated by gel filtration) solubilized by muramidases were considerably larger (tetramer and oligomer) in the microcysts than in the vegetative cells (mostly dimer). There was a transient decrease in cross-linking (measured as an increase in the amount of free amino group of diaminopimelic acid) during the stage of microcyst formation when the cells converted from ovoids to spheres. At the same time, there occurred a large and rapid increase in a galactosamine derivative which may have reflected the synthesis of capsular material. Immediately prior to this period of morphogenesis, the cells became resistant to penicillin but remained sensitive to d-cycloserine. The walls of vegetative cells were completely disaggregated by trypsin and sodium lauryl sulfate, suggesting a discontinuous peptidoglycan layer. This was no longer apparent after the ovoid-sphere stage of microcyst formation. The relationship to morphogenesis of the chemical changes in the cell wall is discussed.

Amino Acids↗

PubMed1967

The challenge of change.

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Adolescent↗

PubMed1967

Taxonomy of anaerobic thiobacilli.

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Oxygen Consumption↗

PubMed1966

The antigenic determinants of the protein-polysaccharides of cartilage.

1. Protein-polysaccharides isolated from bovine, human, and porcine cartilage are antigenic in the rabbit. 2. PP-L from each of these species contains a minimum of two antigenic determinants; one is species specific, and one is common to all three species. Human PP-H also contains these two determinants. 3. Both antigenic determinants are in, or closely associated with, the protein moiety of the compound. Chondroitin sulfate and keratan sulfate were not demonstrated to be antigenic in these studies.

Agglutination Tests↗

PubMed1966

Taxonomy of the acidophilic thiobacilli.

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Sulfur↗

PubMed1966

Effects of alpha-glycerophosphate and of palmityl-coenzyme A on lipid synthesis in yeast extracts.

White, David (Ames Research Center, Moffett Field, Calif.), and Harold P. Klein. Effects of alpha-glycerophosphate and of palmityl-coenzyme A on lipid synthesis in yeast extracts. J. Bacteriol. 91:1218-1223. 1966.-The incorporation of acetate into fatty acids, but not into nonsaponifiable lipids, was stimulated by alpha-glycerophosphate in a supernatant fraction of Saccharomyces cerevisiae, obtained after centrifugation at 86,000 x g for 60 min. There was a pronounced effect at concentrations below 2 mm, but at concentrations above 5 mm alpha-glycerophosphate was relatively less stimulatory. alpha-Glycerophosphate markedly increased the percentage of esterified fatty acids among the products, and the formation of both saturated and unsaturated fatty acids was stimulated. Palmityl-coenzyme A inhibited fatty acid synthesis, affecting the formation of unsaturated acids more severely than saturated acids. In the presence of sufficient alpha-glycerophosphate to alleviate these inhibitions, palmityl-coenzyme A still reduced the formation of certain unsaturated fatty acids.

Acetates↗