Genetic variation at the <i>omp2</i> porin locus of the brucellae: species‐specific markers

Ficht, Thomas A.; Bearden, Scott W.; Sowa, Blair A.; Marquis, Hélène

doi:10.1111/j.1365-2958.1990.tb00688.x

Cited by 77 publications

(60 citation statements)

References 14 publications

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“…The hypothesis of the presence of two similar copies of omp2a in B. ovis, instead of one copy of omp2a and one copy of ompZb for the other Brucella species (Ficht et al, 1990), is supported by our PCR-RFLP results. However, the similarity between the two copies is more divergent in B.…”

Section: Discussionsupporting

confidence: 76%

“…3). This observation confirms the results published by Ficht et al (1990) concerning the absence of a 120 bp segment in the omp2a genes of B. abortus bv. 1, 2 and 4.…”

Section: Polymorphism Of the Brucella Genes Encoding 36 Kda Ompssupporting

confidence: 82%

“…( , 1989 Ficht, 1993). In addition, Ficht et al (1990) t Strain numbers as referred to in first column of Table 1.…”

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confidence: 99%

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Restriction site polymorphism of the genes encoding the major 25 kDa and 36 kDa outer-membrane proteins of Brucella

et al. 1995

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Seventy-seven Bmcella reference and field strains from different geographic origins and hosts representing the six recognized species and their different biovars were analysed for diversity of their genes encoding the major 25 and 36 kDa outer-membrane proteins (OMPs) by PCR-RFLP. The 25 kDa OMP is encoded by a single gene (omp25) whereas two closely related genes (omp2a and omp2b) encode and potentially express the 36 kDa OMP. Analysis of PCR products of the omp25 gene digested with nine restriction enzymes revealed two species-specific markers, i.e. the absence of the EcoRV site in all Brucella melitensis strains and an N 50 bp deletion a t the 3' terminal end of the gene in all Brucella owis strains. Analysis of PCR products of the omp2a and omp2b genes digested with 13 restriction enzymes indicated a greater diversity than the omp25 gene among the six Bmcella species and within the Bmcella abortus, Brucella suis, B. melitensis and B. ovis species. Greater polymorphism was also detected for the omp2b than for the omp2a gene, especially in B. owis which seemed to carry two similar (but not identical) copies of omp2a instead of one copy each of omp2a and omp2b for the other Bmcella species as was previously suggested by Ficht et a/. (1990; Mo/ Microbiol4,1135-1142). Results of PCR-RFLP indicated that distinction can be made between Brucella species and some of their biovars, except between B. canis and B. suis bv. 3 and 4, on the basis of the size and diversity of their major OMP genes, and that it could be of importance for diagnostic, epidemiological and evolutionary study purposes.

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Section: Discussionsupporting

confidence: 76%

“…3). This observation confirms the results published by Ficht et al (1990) concerning the absence of a 120 bp segment in the omp2a genes of B. abortus bv. 1, 2 and 4.…”

Section: Polymorphism Of the Brucella Genes Encoding 36 Kda Ompssupporting

confidence: 82%

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Restriction site polymorphism of the genes encoding the major 25 kDa and 36 kDa outer-membrane proteins of Brucella

et al. 1995

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“…Recently a molecular biotyping approach has been proposed on the basis of restriction endonuclease polymorphism in the genes encoding the major outer proteins of Brucella membrane [33]. The Omp2 gene exists as a locus of two nearly homologous repeated copies that differ slightly among Brucella species and biotypes [34]. We used previous information to design specific primers that amplify a 720 bp fragment lanes 3, 4 and 5 shows the positive samples taken from first farm after vaccination with RB51 vaccine, whereas lane 7 only positive samples collected from second farms, Lanes 6 and 8 were negative for PCR against brucella species.…”

Section: Discussionmentioning

confidence: 99%

Seroprevalence and Molecular Epidemiology of Brucellosis in Cattle in Egypt

Hady¹,

Ahmed²

2016

Adv Dairy Res

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The study was applied on 4772 lactating and non-lactating cows distributed on different districts in Al Sharqia Governorate. Sera were collected from animals during routine diagnosis and control program. The results of screening tests Buffer acidified plate antigen test (BAPAT), Rose Bengal plate test (RBPT), Tube agglutination test (TAT), Complement fixation test (CFT) and indirect enzyme linked immunosorbent assay gave 124 and 176 seroreactive animals by incidence of 4.42% and 8.91% in private farms and individual cases respectively. 37 (29.8%) and 97 (55.1%) isolates of Brucella melitensis biovar 3 were recovered from 124 and 176 seroreactive animals respectively. In seroreactive cows, Brucella melitensis biovar 3 was isolated from 36% and PCR yielded expected products in 40%. In conclusion, more attention should be paid to the role of Brucella melitensis biovar 3 in brucellosis in cattle during the application of national program of brucella control and eradication.

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“…The pattern of porin gene expression in the other Brucella strains is still unknown. The polymorphism of both porin genes has been extensively studied, and restriction fragment length polymorphism (RFLP) studies have identified 11 omp2b variants and 8 omp2a variants (6,16). The omp2 locus sequences in the different Brucella species show complex variability, involving gene conversion phenomenon between the closely related inverted gene copies (17).…”

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confidence: 99%

Molecular, Antigenic, and Functional Analyses of Omp2b Porin Size Variants of Brucella spp

et al. 2001

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Omp2a and Omp2b are highly homologous porins present in the outer membrane of the bacteria from the genus Brucella, a facultative intracellular pathogen. The genes coding for these proteins are closely linked in the Brucella genome and oriented in opposite directions. In this work, we present the cloning, purification, and characterization of four Omp2b size variants found in various Brucella species, and we compare their antigenic and functional properties to the Omp2a and Omp2b porins of Brucella melitensis reference strain 16M. The variation of the Omp2a and Omp2b porin sequences among the various strains of the genus Brucella seems to result mostly from multiple gene conversions between the two highly homologous genes. As shown in this study, this phenomenon has led to the creation of natural Omp2a and Omp2b chimeric proteins in Omp2b porin size variants. The comparison by liposome swelling assay of the porins sugar permeability suggested a possible functional differences between Omp2a and Omp2b, with Omp2a showing a more efficient pore in sugar diffusion. The sequence variability in the Omp2b size variants was located in the predicted external loops of the porin. Several epitopes recognized by anti-Omp2b monoclonal antibodies were mapped by comparison of the Omp2b size variants antigenicity, and two of them were located in the most exposed surface loops. However, since variations are mostly driven by simple exchanges of conserved motifs between the two genes (except for an Omp2b version from an atypical strain of Brucella suis biovar 3), the porin variability does not result in major antigenic variability of the Brucella surface that could help the bacteria during the reinfection of a host. Porin variation in Brucella seems to result mainly in porin conductivity modifications.Porins are abundant proteins in the outer membrane of gram-negative bacteria. They create a controlled permeability of the outer membrane toward small hydrophilic solutes such as sugars that are otherwise not allowed to diffuse through the outer membrane (for a review, see references 21, 22, and 24). In a sense, porins are the Achilles' heel of this protective barrier, since they can act as receptors for bacteriophage and colicins (13), surface-exposed antigens (37), complement-binding sites (29), and the gate of entry for some antibiotics (27,28). In some pathogenic bacteria, such as Neisseria gonorrhoeae, porin sequence variations between serotypes are well described and probably allow successive infection by different serotypes presenting different surface-exposed epitopes (20). Neisseria porin genes are subject to frequent horizontal transfer movements of genetic material, allowing for numerous changes in sequence that can hamper vaccine development (18).Brucellae are gram-negative pathogens infecting numerous mammalian species and causing economic losses in domestic cattle, sheep, and goats, as well as human health problems in zones where they are endemic. The mechanisms of pathogenicity of Brucella spp. are still poorly understoo...

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Genetic variation at the omp2 porin locus of the brucellae: species‐specific markers

Cited by 77 publications

References 14 publications

Restriction site polymorphism of the genes encoding the major 25 kDa and 36 kDa outer-membrane proteins of Brucella

Restriction site polymorphism of the genes encoding the major 25 kDa and 36 kDa outer-membrane proteins of Brucella

Seroprevalence and Molecular Epidemiology of Brucellosis in Cattle in Egypt

Molecular, Antigenic, and Functional Analyses of Omp2b Porin Size Variants of Brucella spp

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