A particulate preparation from Micrococcus lysodeikticus was used to synthesize cell-wall mucopeptide. Radioactive iodinated vancomycin became attached to the preparation simultaneously with a complete inhibition of mucopeptide synthesis. After mucopeptide synthesis had occurred in the absence of antibiotic, the preparation took up more vancomycin, suggesting that new binding sites terminating in acyl-d-alanyl-d-alanine had been produced. The mucopeptide product was divided into a soluble and an insoluble portion, both sensitive to lysozyme. The soluble portion did not combine with vancomycin and hence had presumably lost its terminal d-alanine residues, either by transpeptidation or because of carboxy-peptidase action. The synthesis of both portions was unaffected by the presence of penicillin, but the insoluble part showed increased affinity for vancomycin, thus indicating that penicillin had caused conservation of d-alanyl-d-alanine termini.
The cell wall compositions of two strains of "true" nocardiae, Nocardia asteroides R 399 and N. caviae IM 1381, and two strains of "so-called nocardiae," N . piracicabensis and N. mediterranei, were determined. Two different methods were used for preparing the cell walls. In the one, the bacteria were sonically treated, and the cell walls were obtained by differential centrifugation; in the other, the bacteria were delipidated before sonic treatment. The cell walls of true nocardiae contain nocardic acids, identified by comparison with nocardic acids isolated from the whole cell. The peptidoglycan structures of the "true" and "so-called" nocardiae studied showed some important differences. I n the true nocardiae, the glycan strand is constituted of P-N-acetylglucosaminyl ( 1 -+ 4) N-glycolylmuramic acid, and muramic acid is N-acetylated in the strains of "so-called nocardiae," as it is in the majority of bacteria. In addition, the peptide monomers of true nocardiae are diamidated on both the a-carboxyl group of wglutamic acid and the (L) carboxyl group of meso-diaminopimelic acid, whereas the peptide monomers of the "socalled nocardiae" have only one amide substituent on the carboxyl group of mesodiaminopimelic acid. I t is difficult to differentiate without ambiguity members of the genus Nocardia from the mass of the other actinomycetes which contain major amounts of meso-diaminopimelic acid. Our results suggest that true nocardiae may be those actinomycetes whose cell walls contain, in addition to arabinose and galactose, N-glycolylmuramic acid in the glycan part of the peptidoglycan and diamidated peptides in the peptide part of the peptidoglycan. In addition, true nocardiae contain nocardic acids.The differentiation between nocardiae and related organisms is often quite difficult. Morphologically the genus Nocardia contains filamentous, branching bacteria (19). The validity of this characteristic as a differential criterion has been criticized in past years, and biochemical or chemical tests have been proposed to establish a more precise classification (20). Since the initial work of Cummins (7, 8), cell wall composition has proven to be most useful in classifying organisms belonging to the order Actinomycetales. For example, LL-diaminopimelic acid (Dpm) is found in the cell walls of streptomycetes and rneso-Dpm in the cell walls of nocardiae (2).Moreover, some sugars, such as arabinose and galactose, are found in the celi walls of nocardiae but not in those of streptomycetes. Recently it has been proposed that the specific lipids present in whole cells of nocardiae be used to differentiate nocardiae from streptomycetes (27) and from mycobacteria (17,21). Since the first isolation of nocardic acids from Nocardia asteroides (25) and the determination of their structure (3, 4), nocardic acids with related structures have been found in all the species of Nocardia so far examined. Nocardic acids are a-branched, P-hydroxylated acids of the mycolic type; they have recently been found in the cell walls of Nocardia ...
Lipopolysaccharides from a Slightly Virulent Strain of Yersinia pestisLipopolysaccharides from a slightly virulent strain of Yersinia pestis were investigated. TWO types of lipopolysaccharides were obtained from the bacteria : lipopolysaccharide I was extracted with aqueous phenol/chloroform/hexane while lipopolysaccharide I1 was extracted with phenol/ water. Chemical analysis of these lipopolysaccharides shows the presence of D-glucose, galactose, glucosamine, L-glycero-D-manno-heptose, D-glycero-D-manno-heptose, 3-deoxyoctulosonic acid, phosphate, 3-hydroxymyristic acid, and small quantities of palmitic acid and palmitoleic acid. In addition, lipopolysaccharide I1 contains arabinose.Lipopolysaccharides I and I1 were methylated ; analysis by gas-liquid chromatography and by mass spectrometry indicated the presence of 2,3,4,6-tetra-O-methyl glucose, 2,3,4,6-tetra-O-methyl galactose and of tri-, tetra-and penta-methylated heptose derivatives. Arabinose in lipopolysaccharide I1 was not methylated and is therefore entirely substituted, while glucose and galactose are not substituted. Sodium metaperiodate nearly entirely oxidized glucose and galactose. Part of the heptose was not degraded by periodate oxidation, while part was converted into mannose.Lipopolysaccharides I and I1 could be the R and S forms of the lipopolysaccharide respectively, the S form containing an 0-specific chain with arabinose.The lipopolysaccharides were hydrolysed with acetic acid and degraded polysaccharides I and I1 were obtained. A large part of the arabinose was lost during the hydrolysis of lipopolysaccharide I1 into polysaccharide 11, thus indicating that the arabinose might be in the furanose form.The absence of phosphate groups in polysaccharides I and 11 suggests the absence of bridges between the chains. However, if such bridges exist in the lipopolysaccharides, they are either on 3-deoxyoctulosonic acid or on lipid A.La vaccination antipesteuse est realiske soit avec des souches virulentes apres sterilisation [l, 21 soit avec des souches a virulence attenute [3J. Dans ce dernier cas, ce sont essentiellement les souches Tjiwidej de Otten [3 J et EV de Girard [4 -61 qui sont a l'origine des vaccins antipesteux. La souche EV est affaiblie dans sa virulence, l'administration par voie sous-cutanee est supportee par le cobaye alors que l'administration de la m&me dose par voie intraperitoneale peut &tre mortelle. L'eficacitk du vaccin EV a Ctt 6tudit.e chez la souris [7,8]
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