Intraspecies polymorphism of vsp genes and expression profiles of variable surface protein antigens (Vsps) in field isolates of Mycoplasma bovis

Beĭer, T. V.; Hotzel, Helmut; Lysnyansky, Inessa; Grajetzki, Christine; Heller, Martin; Rabeling, Barbara; Yogev, David; Sachse, Konrad

doi:10.1016/s0378-1135(98)00238-7

Cited by 34 publications

(36 citation statements)

References 25 publications

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“…The leader sequences possess an overall nucleotide and amino acid identity of 76% (92% aa similarity), and this high identity continues for a short distance into the mature polypeptide, with the next 4 aa being identical between all genes, but drops to about 50% for the following 19 aa, after which no overall significant identity could be found. These same vpma 5Ј untranslated and N-terminal-coding regions are also conserved in the equivalent regions of the vsp genes from M. bovis (3,20,23); however, beyond this, vsp genes have no significant similarity to any vpma genes in M. agalactiae.…”

Section: Resultsmentioning

confidence: 95%

“…Detailed genetic analyses have suggested that the vpma system is composed of several genes, two of which have been sequenced (16). The 5Ј untranslated regions and those encoding the signal peptide were found to be conserved within the vpma family and revealed a high identity to the equivalent regions in genes encoding a family of lipoproteins, called Vsps, in the phylogenetically related species M. bovis (3,20,23). Based on these data, the Vpmas of M. agalactiae were proposed to represent a system homologous to the Vsps in M. bovis (16).…”

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confidence: 99%

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Surface Diversity in Mycoplasma agalactiae Is Driven by Site-Specific DNA Inversions within the vpma Multigene Locus

et al. 2002

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The ruminant pathogen Mycoplasma agalactiae possesses a family of abundantly expressed variable surface lipoproteins called Vpmas. Phenotypic switches between Vpma members have previously been correlated with DNA rearrangements within a locus of vpma genes and are proposed to play an important role in disease pathogenesis. In this study, six vpma genes were characterized in the M. agalactiae type strain PG2. All vpma genes clustered within an 8-kb region and shared highly conserved 5 untranslated regions, lipoprotein signal sequences, and short N-terminal sequences. Analyses of the vpma loci from consecutive clonal isolates showed that vpma DNA rearrangements were site specific and that cleavage and strand exchange occurred within a minimal region of 21 bp located within the 5 untranslated region of all vpma genes. This process controlled expression of vpma genes by effectively linking the open reading frame (ORF) of a silent gene to a unique active promoter sequence within the locus. An ORF (xer1) immediately adjacent to one end of the vpma locus did not undergo rearrangement and had significant homology to a distinct subset of genes belonging to the integrase family of site-specific xer recombinases. It is proposed that xer1 codes for a site-specific recombinase that is not involved in chromosome dimer resolution but rather is responsible for the observed vpma-specific recombination in M. agalactiae.Mycoplasmas belong to a group of cell wall-less pathogens that are widespread in nature and cause diseases that are generally chronic and difficult to eradicate in humans, animals, plants, and insects. Among free-living organisms, they possess one of the smallest genomes, which is mainly responsible for their parasitic lifestyle. Yet, despite having a limited coding capacity relative to other bacteria, mycoplasmas have developed quite an extensive repertoire of molecular mechanisms to generate surface protein variability at a high frequency either by phase or size variation (10,28,42). Many of these surface proteins belong to multigene families of lipoproteins that have the ability to switch the expression of individual components on and off and are suspected of playing a role in host cell adhesion. The ability of these proteins to switch expression between different forms is believed to be important in immune evasion and rapid adaptation in the host.Mycoplasma agalactiae is the major etiological agent of the syndrome contagious agalactia, which primarily causes mastitis, arthritis, and keratoconjunctivitis in sheep and goats (4). Recently, a family of related but distinct surface lipoproteins, designated Vpmas, has been identified in this pathogen, and Vpma expression has been shown to undergo high-frequency variation (16). Vpmas are abundantly expressed in M. agalactiae and display an unusual processing of lipoproteins in which a peptidase II-like enzyme cleaves 2 amino acids (aa) (position Ϫ2) N terminal to the cysteine residue rather than at the cysteine to which the lipid anchor is attached. This atypical proc...

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Section: Resultsmentioning

confidence: 95%

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confidence: 99%

Surface Diversity in Mycoplasma agalactiae Is Driven by Site-Specific DNA Inversions within the vpma Multigene Locus

et al. 2002

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“…They comprise a large family of lipoprotein antigens located on the surface of M. bovis and have been suggested as playing a critical role in the attachment of M. bovis cells to host cells (Beier et al, 1998, Lysnyansky et al, 1999, Nussbaum et al, 2002, van der Merwe et al, 2010. Within the M. bovis PG45 type strain genome, a total of 13 single-copy vsp genes organised in a chromosomal cluster have been identified and characterised (Lysnyansky et al, 1999).…”

Section: Variable Surface Proteinsmentioning

confidence: 99%

“…Within the M. bovis PG45 type strain genome, a total of 13 single-copy vsp genes organised in a chromosomal cluster have been identified and characterised (Lysnyansky et al, 1999). These Vsp proteins have been shown to spontaneously undergo non-coordinate phase variation, between on-and off-expression states, with high frequency both in vivo and in vitro (Beier et al, 1998, Buchenau et al, 2010, Lysnyansky et al, 1996, Lysnyansky et al, 1999.…”

Section: Variable Surface Proteinsmentioning

confidence: 99%

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Mycoplasma bovis in Australian feeder cattle

Schibrowski¹

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Mycoplasma bovis can be a commensal bacterial inhabitant of the upper respiratory tract of healthy bovines. However, under certain circumstances and conditions that are incompletely understood, M. bovis can be associated with a number of clinical syndromes, one of which is bovine respiratory disease (BRD). In Australia, there is little information on the prevalence and epidemiology M. bovis in beef production systems. The overall aim of this thesis was to help close this knowledge gap.Commercially available serological diagnostic methods for the detection of M. bovis-specific antibody have not been validated in the Australian cattle population. Arguably, more importantly, however is the fact that diagnostic sensitivity (Se) and specificity (Sp) and / or analytical sensitivity (ASe) and specificity (ASp) estimates for commercially available M. bovis sero-diagnostic tests are not available. 28% (95% CI: 1% -92%). However, in terms of Sp the commercial ELISAs out performed western blotting; BioK302: 96% (95% CI: 87% -99%); BioK260:100% (95% CI: 93% -100%) and western blotting: 88% (95% CI: 56% -98%) respectively. In terms of both Se and Sp combined, none of the methods assessed here performed well. As such, when interpreting the results obtained from these ELISAs, the potential impact imperfect Se and / or Sp can have needs to be considered.Despite the poor performance of the BioK302 and BioK260 ELISAs particularly in terms of Se, these tests were used to determine the sero-prevalence of M. bovis antibody in Australian feeder cattle at feedlot induction and draft (approximately 42 days on feed). Paired bovine sera from 1,354 randomly selected animals were sourced from a bovine serum bank (n = 35,160) collected as part of another study, The National Bovine Respiratory Disease Initiative. As the classification of the result of a single serum sample could differ between the BioK302 and BioK260, sero-prevalence estimates were obtained using the individual ELISA results in addition to series and parallel interpretation of the two ELISA kit results. The apparent sero-prevalence of M. bovis-specific antibody at feedlot induction estimates ranged from 2.4% -6.8% (95% CI: 1.3% -8.6%) and the apparent sero-prevalence estimates at draft ranged from 22.4% -44.2% (95% CI: 19.1% -48.6%). The level of sero-conversion to M. bovis between induction and draft was also determined. Only animals that were classified as sero-negative at induction were included in sero-conversion analyses. In the current study, 24.3% (95% iii CI: 20.8% -27.7%) and 19.5% (95% CI: 17.3% -21.7%) of animals sero-converted to M. bovis between induction and draft based on the BioK302 and dichotomised BioK260 ELISA results respectively.Using these ELISA results, an assessment of putative risk factors associated with sero-positivity at feedlot induction or sero-conversion between induction and draft was performed. An increased risk of sero-positivity at feedlot induction was found to be associated with; (i) history of exposure to a saleyard at least 27 d...

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