title: Simultaneous expression of smooth and rough phase properties related to lipopolysaccharide in a strain of Brucella melitensis.
abstract: Brucella strains exhibit either a rough (R) or a smooth (S) colonial phase identifiable by bacteriological methods. This depends on the biosynthesis and translocation to the surface in S but not in R strains, of the O-polysaccharide chain of the lipopolysaccharide (LPS) molecule. B. melitensis biovar 1 strain EP exhibited simultaneously both S and R characteristics in relation to colonial morphology, agglutination by monospecific anti-M and anti-R sera, activity of bacteriophages lytic for rough Brucella spp. (phage R/C) and for smooth B. melitensis (phage Iz). B. melitensis strain EP expressed fewer O-chains with a similar distribution of molecular weights than B. melitensis reference strain 16M by SDS-PAGE and immunoblotting, but higher amounts of R-LPS. Quantitative determination of S-LPS by a turbidimetric latex inhibition immunoassay with monoclonal antibodies confirmed the limited expression of S-LPS in strain EP. As with other gram-negative bacteria, the phenomenon could be attributed to a deficiency in one step of the biosynthetic assembly of the O-chains.
authors.affiliation: Laboratoire de Pathologie Infectieuse et Immunologie, Institut National de la Recherche Agronomique, Nouzilly, France.
authors.forename: R A
authors.initials: RA
authors.lastname: Bowden
authors.forename: J M
authors.initials: JM
authors.lastname: Verger
authors.forename: M
authors.initials: M
authors.lastname: Grayon
authors.forename: J N
authors.initials: JN
authors.lastname: Limet
authors.forename: G
authors.initials: G
authors.lastname: Dubray
mesh_terms: D017347:Brucella melitensis / Q000145:classification / Q000254:growth & development* / Q000378:metabolism; D002006:Brucellosis / Q000382:microbiology; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D007841:Latex Fixation Tests; D008070:Lipopolysaccharides / Q000737:chemistry / Q000378:metabolism*; D009391:Nephelometry and Turbidimetry
chemical_list: D008070:Lipopolysaccharides