Lipopolysaccharides d'une Souche à Virulence Atténuée de Yersinia pestis

Abstract

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]

Modification of the Structure and Activity of Lipid A inYersinia pestisLipopolysaccharide by Growth Temperature

“…In our preliminary experiments we found that Y. pestis strain Yreka (a virulent strain) produced a lipid A containing 3-OH-C 14:0 as the only fatty acid component when grown at 37°C. Controversial results were reported by other groups using the avirulent strain EV40 grown at 28°C (4,39). In this study, to clarify this discrepancy, we analyzed the lipid A from cells grown at 27°C or 37°C by MALDI-TOF mass spectrometry, and we found that at the low growth temperature (27°C) Y. pestis produced a lipid A containing larger amounts of C 16:1 and C 12:0 than the lipid A produced at the high growth temperature (37°C), as shown in Fig.…”

“…The palmitoleoyl transferase that functions at low temperatures was identified, and its character was studied (6). Since C 16:1 was also present in the lipid A of Y. pestis (2,4,39), we assumed that a similar phenomenon could occur in this bacterium. Furthermore, it was proved by several groups (15,32,36) using synthetic lipid A compounds that the amounts, kinds, and linkages of fatty acids in lipid A influenced its biological activity.…”

“…Hartley et al reported that nearly 90% of fatty acids in the lipid A of Y. pestis strain 195/R (a virulent strain) consisted of 3-OH-C 14:0 (14). On the other hand, considerable amounts of lauric acid (C 12:0 ), palmitic acid (C 16:0 ), and palmitoleic acid (C 16:1 ) were detected in the lipid A of Y. pestis strain EV40 (an avirulent strain) (4,39). Using the same strain, Aussel et al (2) proposed a hexa-acylated lipid A structure (four molecules of 3-OH-C 14:0 , one of C 12:0 , and one of C 16:1 ).…”

The failure of different strains of Yersinia pestis to produce lipopolysaccharide O-antigen under different growth conditions is due to mutations in the O-antigen gene cluster

“…Some workers have reported that it lacked an O-antigen [11,12] and consisted of lipid A bound to the core oligosaccharide by 3-deoxy-D-manno-octulosonic acid (KDO) [13]. Others have reported that both rough and smooth forms of LPS were produced [14] or that the synthesised O-antigen was shed into the growth media [15]. There have also been suggestions that the ¢ne structure of Y. pestis LPS is thermo-regulated.…”

The failure of different strains ofYersinia pestisto produce lipopolysaccharide O-antigen under different growth conditions is due to mutations in the O-antigen gene cluster

“…Some workers have reported that it lacked an O‐antigen [11,12] and consisted of lipid A bound to the core oligosaccharide by 3‐deoxy‐ d ‐manno‐octulosonic acid (KDO) [13]. Others have reported that both rough and smooth forms of LPS were produced [14] or that the synthesised O‐antigen was shed into the growth media [15]. There have also been suggestions that the fine structure of Y. pestis LPS is thermo‐regulated.…”