Comparison of Chemical Components of Cell Walls of Brucella abortus Strains of Low and High Virulence

Abstract

Amino acid, carbohydrate, and lipid components of cell walls of Brucella abortus strain 19A (low virulence) and strain 2308 (high virulence) were compared by thin layer chromatography (TLC) and by use of an amino acid analyzer. A total of 15 amino acids were detected by both chromatographic methods. Each amino acid was present in greater amounts in strain 2308 than in strain 19A when equal amounts of hydrolysates of cell wall and endotoxin-containing preparations were analyzed. A component with the same R, value as ethanolamine was present in strain 2308 cell wall hydrolysates but was not revealed by TLC of strain 19A cell wall hydrolysates. This component was not detected with the amino acid analyzer. TLC of cell walls tagged with 2 ,4-dinitrofluorobenzene prior to hydrolysis showed that phenylalanine was a terminal amino acid in cell walls of B. abortus strains 19A and 2308, B. suis strain 1776, and B. melitensis strain 2500. Carbohydrates detected in cell walls of strains 19A and 2308 by TLC were tentatively identified as glucose, mannose, rhamnose, and galactose. Colorimetric tests were also positive for 2-keto-3-deoxyoctulosonic acid, heptose, and dideoxyhexose. At least seven lipid components were detected by TLC of ether extracts of cell walls of strains 19A and 2308. It is suggested that one or more lipids is important in maintaining cell wall structure, because isolated cell walls rapidly became fragmented after exposure to ether.

Purification and characterization of smooth and rough lipopolysaccharides from Brucella abortus

“…There are conflicting reports on the presence of heptose in brucella S-LPS. Although some investigators (26)(27)(28)41) reported heptose, Hurvell and Lindberg (19) did not detect it on analysis by GLC of S-LPS (f5) extracted by the Redfearn method. We also could not detect this sugar in the S-LPS and R-LPS of B. abortus.…”

A 36-kilodalton Brucella abortus cell envelope protein is encoded by repeated sequences closely linked in the genomic DNA

“…The currently approved vaccine strain, S19, has several disadvantages, including human infectivity and virulence, and a low level of persistently infected, vaccinated cattle (10,15,45). The search for improved vaccines or diagnostic reagents capable of distinguishing field strain infections from S19-vaccinated or persistently infected animals comprises most current Brucella research (9,12,28,46,50,51,64,65).…”

Soluble antigens of virulent and attenuated biotypes of Brucella abortus

“…Although quantitative antigenic differences are recognized among B. abortus biotypes, qualitative differences may be more closely related to virulence of these species. Several studies on the immunity invoked by challenge of animals with Brucella antigens suggest that a substance, absent in attenuated organisms, is responsible for preventing destruction of virulent strains during phagocytosis (12,17,23). Thus, the demonstration of antigens or components common to virulent biotypes that are not apparent in attenuated or avirulent strains could add to our Photographic and diagrammatic reproductions ofpolyacrylamide gel isoelectric focusing patterns of soluble antigens derived from four strains of B. abortus in a pHgradient of 3.0 to 10.…”

“…In addition, agglutination reactions indicate that quantitative differences in the distribution of two major Brucella agglutinogens (A and M) exist among the different biotypes (19,28). Numerous attempts have been made to demonstrate in virulent strains of brucellae the presence of antigens that are not present in attenuated or avirulent strains (1,8,12,15,17,20,23). Results of such studies suggest that basic studies concerning antigenic differences existing between virulent and attenuated or avirulent strains of different biotypes might contribute to a better understanding of factors related to virulence and/or immunogenicity of Brucella species.…”