Mycoplasma bovigenitalium in the upper genital tract of bulls: spontaneous and induced infections.

Mycoplasma bovigenitalium, was isolated from vesicular gland secretions of a large proportion of clinically normal pubescent bulls. Infections established at this site in 1 to 2 year old bulls sometimes persisted for over a year, induced a local immune response, and were associated in some animals with unacceptably low motility of sperm following freezing of semen for artificial insemination. Inoculation of as few as 1000 cfu directly into the vesicular gland sufficed to establish infection but the naturally occurring syndrome could not be successfully reproduced by this method. Intratracheal injection of the organism produced infection of the upper genital tract in one of two bulls. The ELISA test was more sensitive than the IHA test in detection of antibodies to M. bovigenitalium in serum or vesicular secretions, but its usefulness was limited by extensive cross reactions with other Mycoplasma species.

Outer membrane proteins of Brucella abortus: isolation and characterization.

Outer membrane proteins were derived from one rough and four smooth strains of Brucella abortus by sequential extraction of physically disrupted cells with N-lauroylsarcosinate and dipolar ionic detergent. Extraction of outer membrane proteins was ineffective, however, without predigestion with lysozyme. Three groups of proteins were present and could be separated in their native state by sequential anion-exchange chromatography and gel filtration. Membrane proteins contained substantial quantities of tightly adherent lipopolysaccharide which could be reduced but not eliminated by extraction of cells with trichloroacetic acid before disruption. Group 2 proteins, apparently trimers in their native state, gave rise to 43,000- and 41,000-molecular-weight bands after complete denaturation in sodium dodecyl sulfate. They were antigenically identical among all the strains, showed close resemblance in amino acid composition to each other and a general similarity to OmpF of Escherichia coli, and are proposed to be the porins of B. abortus. Group 3 proteins occurred as 30,000-molecular-weight bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, although additional bands were frequently observed in this region. In none of the strains did group 3 proteins manifest heat-modifiable characteristics. Proteins of different strains bore a high degree of similarity to each other in amino acid composition, except in methionine, isoleucine, tyrosine, and histidine. Differences occurred consistently in amino acid composition between group 2 and 3 proteins, and some of these correspond to differences between OmpF and OmpA. Group 2 and 3 proteins were antigenically distinct from each other, but the principal group 3 antigens were shared among all the strains. Despite the lack of heat modifiability, perhaps influenced by adherent lipopolysaccharide, group 3 proteins are proposed as counterparts to OmpA. Most of the group 1 proteins, minor components, were physically associated with those of group 3 unless in sodium dodecyl sulfate. Group 1 proteins produced a major band at 94,000 and exhibited heat modifiability. No evidence was found of a low-molecular-weight lipoprotein in the outer membrane of B. abortus, but this is not taken to exclude its occurrence.

Evaluation of a transport medium for campylobacter (Vibrio) fetus.

A quantitative assessment was performed on a serum enrichment medium for Campylobacter (Vibrio) fetus, to test its effectiveness as a transport medium. Abundant yields of C fetus were obtained with an inoculum size of 10(4), even after keeping the medium in air at 22 to 23 C for 4 days prior to incubation at 37 C under microaerophilic conditions. The organism could be isolated from the medium kept in air at 22 to 23 C for at least 2 days, with an inoculum as small as 100 organisms. It was concluded that this formulation comprises a convenient and effective transport medium for field use. Transit time should not exceed 3 days and, ideally, should be restricted to less than or equal to 2 days. At least duplicate vials of transport medium should be inoculated with each sample.