Gram-negative bacteria, occurrence

Occurrence and Linkages of KDO in Lipopolysaccharides from Gram-Negative Bacteria... 

The occurrence of this group of sugar nucleotides is limited mainly to the cells of Gram-negative bacteria. Those bacterial mutants defective in lipopolysaccharide synthesis are useful for preparative isolation of such esters, as the concentration of sugar nucleotides in normal cells is very low. 

Up to now, enzymatic isomerization has been evidenced mainly in Pseudomonas and Vibrio species. The fact that such an adaptation system was found in these organisms explains their wide occurrence in all niches of a great number of ecosystems, comprising soil, human skin, and water, also in comparison with other Gram-negative bacteria or species lacking such adaptation. 

Candidosis may affect the web spaces of the toes. Marked maceration with a thick, white horny layer is the usual clinical symptom. Gram-negative bacteria are often copathogens. Work circumstances that favour tinea pedis can also play a role in the occurrence of candidosis of the toewebs. 

The occurrence of sialic acids in bacteria and their relationship to pathogenicity have been studied in some detail. Aaronson and Lessie (1960) examined the presence of sialic acids in several classes of bacteria and concluded that sialic acids are limited to the gram-negative bacteria. A later study, however, has indicated that some gram-positive bacteria also contain sialic acids, and the species examined all are pathogenic (Irani and Ganapathi, 1962 Luppi and Cavazzini, 1966). In Escherichia coli, both A-acetylneuraminic and N-acetyl-7-O-acetylneuraminic acids... 

The ubiquitous occurrence of bacteria, which can utilize biphenyl as a sole source of carbon and energy, has been reported. Several species of Gram-negative and Gram-positive bacteria have been shown to degrade biphenyl and PCBs. The main pathway for biphenyl catabolism is outlined in Figure 3 [58-66]. 

Many 2-alkylquinolin/4(l//)-one alkaloids bear the trivial names pseudans because of their occurrence in bacteria of the genus Pseudomonas. For example, P. aeruginosa is a ubiquitous gram-negative bacterial pathogen that causes infections not only in human hosts but also in animals and even plants. 

Irani, R. J., and Ganapathi, K., 1%2, Occurrence of sialic acid in some gram-positive and gram-negative pathogenic bacteria. Nature 195 1227. 

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