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Veterinary Research Communications - The black-handed spider monkey (Ateles geoffroyi) is a platyrrhine primate distributed in southern Mexico, Central America, and part of South America. Two...  相似文献   
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Erythrocytes of bovines and other ruminants have a strikingly anomalous phospholipid composition, with low or absent phosphatidylcholine (PC) together with high sphingomyelin (SM) content. Here, we report the presence in normal bovine serum of high levels of anti-phospholipid antibodies of IgM isotype against, PC and the phosphono analogue of phosphatidylethanolamine, aminoethylphosphonolipid (AEPL), normally produced by rumen ciliates. In contrast, no antibodies were detected against SM or N-acyl-phosphatidylethanolamine (NAPE), the major components of bovine erythrocytes. In addition, we found that exposure of the ciliate Tetrahymena thermophila to bovine serum results in rapid lysis, an effect that was inhibited by adsorption of the serum with SM/AEPL liposomes. Furthermore, incubation with bovine serum had a similar effect on freshly obtained ruminal ciliates, and the lytic activity was eliminated by pre-adsorption of the serum with SM/PE liposomes. The ruminant mode of life with its concomitant ciliate fauna is hereby linked to the peculiar conformation of bovine erythrocyte membranes. We propose that the unique phospholipid composition of bovine erythrocytes appears as an evolutionary adaptation to tolerate the lytic effects of anti-phospholipid antibodies generated against AEPL, a membrane component of the huge mass of ruminal ciliates, necessary commensals of this group of mammals.  相似文献   
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The haemoparasites Babesia bovis and Babesia bigemina affect cattle over vast areas of the tropics and temperate parts of the world. Microscopic examination of blood smears allows the detection of clinical cases of babesiosis, but this procedure lacks sensitivity when parasitaemia levels are low. In addition, differentiating between similar haemoparasites can be very difficult. Molecular diagnostic procedures can, however, overcome these problems. This paper reports a quantitative PCR (qPCR) assay involving the use of SYBR Green. Based on the amplification of a small fragment of the cytochrome b gene, this method shows both high sensitivity and specificity, and allows quantification of parasite DNA. In tests, reproducible quantitative results were obtained over the range of 0.1 ng to 0.1 fg of parasite DNA. Melting curve analysis differentiated between B. bovis and B. bigemina. To assess the performance of the new qPCR procedure it was used to screen for babesiosis in 40 cows and 80 horses. B. bigemina was detected in five cows (three of these were also found to be positive by standard PCR techniques targeting the 18S rRNA gene). In addition, B. bovis was detected in one horse and B. bigemina in two horses using the proposed method, while none was found positive by ribosomal standard PCR. The sequences of the B. bigemina cytochrome b and 18S rRNA genes were completely conserved in isolates from Spain and Argentina, while those of B. bovis showed moderate polymorphism.  相似文献   
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Mini- and microsatellite sequences have proven to be excellent tools for the differentiation of strains and populations in several protozoan parasites due to their high variability. In the present work we have searched the genome of the tick-transmitted bovine hemoprotozoon Babesia bovis for tandem repeats (TRs) that could be useful for a multilocus typing system. Hundred and nineteen sequences were shortlisted and tested in five common B. bovis reference isolates originating from distinct geographic locations of North and South America: Texas, USA (T2Bo), Mexico (RAD and Mo7), and Santa Fe and Salta, Argentina (R1A and S2P, respectively). Satellite sequences were PCR-amplified using specific primers, separated by polyacrylamide gel electrophoresis, visualized by silver staining and sized. Fourteen TR sequences could be reliably amplified in all isolates and displayed length polymorphism. All primers used were specific for B. bovis and did not amplify genomic DNA from the bovine host or from Babesia bigemina, the principal co-infecting bovine parasite in the Americas, allowing their future use in field surveys. The 14 satellite markers identified are distributed throughout the four chromosomes of B. bovis as follows: chromosome 1 (n = 3), chromosome 2 (n = 2), chromosome 3 (n = 5), and chromosome 4 (n = 4). Within the five B. bovis isolates we identified nine satellite marker loci with two alleles, three with three alleles, one with four and another with five alleles. In comparison to Theileria parva, a bovine hemoprotozoan that pertains to the same piroplasmida order and owns a genome of similar size, the number of polymorphic TRs and the average number of alleles per TR locus seem to be significantly reduced in the B. bovis genome. Furthermore, the ratio of micro- to minisatellites in both B. bovis and T. parva is considerably lower than in other eukaryotes, as confirmed by bioinformatic analysis. The multilocus genotype of the five B. bovis isolates was assessed and the genetic distance between each other determined followed by cluster analysis based on neighbor joining. The resulting phenogram showed that B. bovis isolates segregated into three clusters according to their geographic origin. The presented marker system is suitable to explore various parameters of B. bovis populations such as genetic diversity, infection dynamics and their structure under different epidemiological situations, which are of crucial importance for improved control strategies.  相似文献   
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Autonomous glycosylphosphatidylinositol (GPI) molecules (also protein-free GPIs or free GPIs) have been reported to be particularly abundant in some parasitic protozoa and mediate strong immunomodulatory effects on the host immune system. In the work at hand we have investigated the existence of free GPIs in Babesia bovis. Comparative thin layer chromatographic analysis of the protein-free glycolipid fraction of in vitro cultured B. bovis merozoites and erythrocyte membranes demonstrated the presence of an abundant parasite-specific band. Its chemical analysis revealed a GPI species containing a chain of two mannose residues, N-glucosamine and non-acylated inositol. The lipid moiety linked to inositol was diacylglycerol. The total fatty acid composition showed predominantly long-carbon chain molecules (12% of C22:0 and 45% of C24:0). The potential of B. bovis to assemble the presented free GPI species was verified by the existence of seven genes in its genome that putatively encode the following GPI biosynthetic enzymes: PI N-acetyl-GlcN-transferase (PIG-A and GPI-1), N-acetyl-GlcN-PI-de-N-acetylase (PIG-L), acyltransferase (PIG-W), dolichyl-phosphate mannosyl transferase (DPM-1), GPI mannosyltransferase I (PIG-M), and GPI mannosyltransferase II (PIG-V). GPI biosynthesis is vital for the intraerythrocytic parasite stage as mannosamine, an inhibitor of GPI biosynthesis, impaired in vitro growth of B. bovis merozoites. Absence of the vast majority of N-glycan metabolism encoding genes in the B. bovis genome underscores that the growth inhibitory effect of mannosamine is attributable to its interference with GPI biosynthesis and not with assembly of N-linked oligosaccharides, as has been described for higher eukaryotes. Elucidation of the structure and biosynthesis of GPI may allow to facilitate the development of future immune interventions against bovine babesiosis.  相似文献   
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The merozoite surface antigens MSA-2 of Babesia bovis constitute a family of polymorphic GPI-anchored glycoproteins located at the parasite cell surface, that contain neutralization-sensitive B-cell epitopes. These are therefore putative vaccine candidates for bovine babesiosis. It was previously shown that (i) the MSA-2 antigens of the biologically cloned Mo7 strain are encoded by four tandemly organized genes: msa-2a1, a2, b and c, and (ii) at least one allele of each of these genes is present in the Argentine R1A strain with a moderate degree of polymorphism. The present work was aimed at defining neutralization-sensitive B-cell epitopes in the MSA-2 family, that are conserved among different B. bovis geographical isolates. To this end, msa-2a, b and c alleles from different isolates from Argentina, USA and Mexico were amplified by PCR, cloned and sequenced. Bioinformatic analysis by ClustalW alignments and B-cell epitope prediction algorithms performed on these sequences allowed the identification of several regions containing putative conserved B-cell epitopes. Four peptides representing these regions: (KDYKTMVKFCN from msa-2a1; YYKKHIS, from msa-2b; and THDALKAVKQLIKT and ELLKLLIEA from msa-2c) were chemically synthesized, conjugated to keyhole limpet hemocyanin and used to inoculate mice to obtain immune sera. Anti-peptide antibodies recognized B. bovis merozoite extracts in all cases in ELISA tests. In addition, these sera reacted with the surface of merozoites of an Argentine and a Mexican B. bovis strains in immunofluorescence assays, and sera against two of the selected peptides inhibited invasion of erythrocytes by in vitro cultured merozoites. Taken together, the results show that the peptide sequences selected by bioinformatic analysis represent expressed and geographically conserved B. bovis B-cell epitopes that might be strong candidates for development of subunit vaccines.  相似文献   
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