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1.
Parasitol Int ; 67(2): 190-195, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29155165

RESUMO

An attenuated live vaccine containing Babesia bovis and B. bigemina cultured in vitro with a serum-free medium was assessed for its clinical protection conferred of naïve cattle, under natural tick-challenge in a high endemicity zone to Babesia spp. Three groups of six animals were treated as follows: group I (GI) received a vaccine derived from parasites cultured with a free-serum medium; group II (GII) were immunized with the standard vaccine, with parasites cultured in a medium supplemented with 40% (v/v) bovine serum; and a control group (GIII) inoculated with non-infected bovine erythrocytes. Inocula were administered by IM route. Experimental animals were kept during 23days after vaccination in a cattle farm free of ticks and Babesia spp. Thereafter, cattle were moved to a high endemicity farm for natural exposure to Babesia spp. transmitted by Rhipicephalus microplus ticks. Protection against clinical babesiosis was observed in bovines belonging to GI (100%) and GII (83.33%), while the control animals (GIII) were not protected, and showed severe clinical signs, closely related to babesiosis, were observed for at least three consecutive days during the challenge. These were fever, anemia, which were measured simultaneously, and circulating parasites were detected by optic light microscopy. All cattle showed B. bovis and B. bigemina in stained blood films during the challenge; B. bovis antibody titers were higher than those to B. bigemina in GI and GII, and lower titers were determined in GIII. The protective capacity of the vaccine derived from B. bovis and B. bigemina cultured in vitro in a serum-free medium was demonstrated.


Assuntos
Babesia bovis/imunologia , Babesia/imunologia , Babesiose/prevenção & controle , Vacinas Atenuadas/administração & dosagem , Anemia/parasitologia , Animais , Anticorpos Antiprotozoários/sangue , Babesia/crescimento & desenvolvimento , Babesia/ultraestrutura , Babesia bovis/crescimento & desenvolvimento , Babesia bovis/ultraestrutura , Babesiose/sangue , Babesiose/imunologia , Babesiose/transmissão , Bovinos , Meios de Cultura Livres de Soro , Febre/parasitologia , Microscopia , Rhipicephalus/parasitologia , Temperatura de Transição , Vacinação/métodos , Vacinas Atenuadas/imunologia
2.
Exp Parasitol ; 131(2): 261-6, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22561041

RESUMO

Babesia bovis contains a prokaryotic derived organelle known as the apicoplast. Many participants of the metabolic pathways within the apicoplast are encoded in the nuclear genome and post-translationally imported with the help of a bipartite signal. Recently, an all encompassing algorithm was derived to predict apicoplast targeted proteins for many non-Plasmodium apicomplexans in which it reported the presence of 260 apicoplast targeted proteins in Babesia. One of these proteins is glutamyl tRNA synthetase (GltX). This study investigates if the putative bipartite signal of GltX alone is sufficient to direct proteins into the apicoplast. Using a transient transfection system consisting of a green fluorescent protein as the reporter, we tested the signal and transit portions of the bipartite signal in apicoplastic transport. We first identified the transcript of gltX to be expressed during the asexual blood stages and subsequently confirmed that the complete bipartite signal is responsible for directing the reporter protein into a compartment distinct from the nucleus and the mitochondrion. As GltX bipartite signal successfully guided the reporter protein into the apicoplast, our finding implies that it also directs native GltX into the same organelle.


Assuntos
Babesia bovis/metabolismo , Glutamato-tRNA Ligase/metabolismo , Organelas/enzimologia , Transdução de Sinais/fisiologia , Animais , Babesia bovis/enzimologia , Babesia bovis/ultraestrutura , Bovinos , Eletroporação , Eritrócitos/parasitologia , Regulação Enzimológica da Expressão Gênica , Processamento de Proteína Pós-Traducional/fisiologia , Transfecção
3.
Parasite Immunol ; 33(1): 34-44, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21155841

RESUMO

The spleen is a critical organ in defence against haemoparasitic diseases like babesiosis. Many in vitro and ex vivo studies have identified splenic cells working in concert to activate mechanisms required for successful resolution of infection. The techniques used in those studies, however, remove cells from the anatomical context in which cell interaction and trafficking take place. In this study, an immunohistological approach was used to monitor the splenic distribution of defined cells during the acute response of naïve calves to Babesia bovis infection. Splenomegaly was characterized by disproportionate hyperplasia of large versus small leucocytes and altered distribution of several cell types thought to be important in mounting an effective immune response. In particular, the results suggest that the initial crosstalk between NK cells and immature dendritic cells occurs within the marginal zone and that immature dendritic cells are first redirected to encounter pathogens as they enter the spleen and then mature as they process antigen and migrate to T-cell-rich areas. The results of this study are remarkably similar to those observed in a mouse model of malarial infection, suggesting these dynamic events may be central to the acute response of naïve animals to haemoparasitic infection.


Assuntos
Babesia bovis/imunologia , Babesia bovis/parasitologia , Babesiose/imunologia , Babesiose/parasitologia , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/parasitologia , Células Dendríticas/imunologia , Células Dendríticas/parasitologia , Imunofenotipagem , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Baço/imunologia , Baço/parasitologia , Esplenomegalia/imunologia , Esplenomegalia/parasitologia , Doença Aguda , Animais , Antígenos de Protozoários/imunologia , Babesia bovis/ultraestrutura , Babesiose/veterinária , Bovinos , Doenças dos Bovinos/fisiopatologia , Contagem de Células , Proliferação de Células , Imuno-Histoquímica , Imunofenotipagem/veterinária , Espectroscopia de Ressonância Magnética , Masculino , Tamanho do Órgão , Baço/fisiopatologia , Esplenomegalia/veterinária
4.
Exp Parasitol ; 123(3): 236-43, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19646439

RESUMO

Apicomplexan parasites commonly contain a unique, non-photosynthetic plastid-like organelle termed the apicoplast. Previous analyses of other plastid-containing organisms suggest that apicoplasts were derived from a red algal ancestor. In this report, we present an extensive phylogenetic study of apicoplast origins using multiple previously reported apicoplast sequences as well as several sequences recently reported. Phylogenetic analysis of amino acid sequences was used to determine the evolutionary origin of the organelle. A total of nine plastid genes from 37 species were incorporated in our study. The data strongly support a green algal origin for apicoplasts and Euglenozoan plastids. Further, the nearest green algae lineage to the Apicomplexans is the parasite Helicosporidium, suggesting that apicoplasts may have originated by lateral transfer from green algal parasite lineages. The results also substantiate earlier findings that plastids found in Heterokonts such as Odontella and Thalassiosira were derived from a separate secondary endosymbiotic event likely originating from a red algal lineage.


Assuntos
Babesia bovis/classificação , Babesia bovis/genética , Clorófitas/classificação , Clorófitas/genética , Filogenia , Plastídeos/genética , Sequência de Aminoácidos , Animais , Apicomplexa/classificação , Apicomplexa/genética , Apicomplexa/ultraestrutura , Babesia bovis/ultraestrutura , Teorema de Bayes , Clorófitas/ultraestrutura , Cianobactérias/classificação , Cianobactérias/genética , Euglênidos/classificação , Euglênidos/genética , Células Eucarióticas/classificação , Funções Verossimilhança , Plastídeos/classificação , Alinhamento de Sequência
5.
Mol Microbiol ; 65(4): 1092-105, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17640278

RESUMO

Sequestration of parasite-infected red blood cells (RBCs) in the microvasculature is an important pathological feature of both bovine babesiosis caused by Babesia bovis and human malaria caused by Plasmodium falciparum. Surprisingly, when compared with malaria, the cellular and molecular mechanisms that underlie this abnormal circulatory behaviour for RBCs infected with B. bovis have been relatively ignored. Here, we present some novel insights into the adhesive and mechanical changes that occur in B. bovis-infected bovine RBCs and compare them with the alterations that occur in human RBCs infected with P. falciparum. After infection with B. bovis, bovine RBCs become rigid and adhere to vascular endothelial cells under conditions of physiologically relevant flow. These alterations are accompanied by the appearance of ridge-like structures on the RBC surface that are analogous, but morphologically and biochemically different, to the knob-like structures on the surface of human RBCs infected with P. falciparum. Importantly, albeit for a limited number of parasite lines examined here, the extent of these cellular and rheological changes appear to be related to parasite virulence. Future investigations to identify the precise molecular composition of ridges and the proteins that mediate adhesion will provide important insight into the pathogenesis of both babesiosis and malaria.


Assuntos
Babesia bovis/fisiologia , Eritrócitos/citologia , Eritrócitos/parasitologia , Animais , Babesia bovis/crescimento & desenvolvimento , Babesia bovis/patogenicidade , Babesia bovis/ultraestrutura , Fenômenos Biomecânicos , Bovinos , Adesão Celular , Células Endoteliais/citologia , Membrana Eritrocítica/parasitologia , Membrana Eritrocítica/ultraestrutura , Eritrócitos/ultraestrutura , Humanos , Estágios do Ciclo de Vida , Microscopia de Força Atômica , Parasitos/crescimento & desenvolvimento , Parasitos/patogenicidade , Parasitos/ultraestrutura , Propriedades de Superfície , Tripsina/metabolismo , Virulência
6.
Exp Parasitol ; 116(1): 91-4, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17207481

RESUMO

In the present study, the subcellular localization of the host red blood cell (RBC) membrane components, the alpha2-3-linked sialic acid (SA) residues and the lipid bilayer, was observed during the asexual growth of Babesia bovis using two erythrocyte probes, the SA-specific lectin (MALII) and the lipophilic fluorescent (PKH2) probes, respectively. In confocal laser scanning microscopy with MALII, the SA residues on the surface of parasitized RBCs appeared to accumulate into the intracellular parasites as the parasites matured as well as to remain on the surface of extracellular parasites. Furthermore, when PKH2-labeled RBCs were infected with B. bovis, PKH2 signals were also observed around both the intracellular and the extracellular parasites, similarly to the results of MALII. These results indicated that the components derived from the host erythrocyte membrane are incorporated into the intracellular parasites during their asexual growth within the parasitized RBC, suggesting the possible formation of a parasitophorous vacuole-based network or a parasite surface coat.


Assuntos
Babesia bovis/crescimento & desenvolvimento , Membrana Eritrocítica/ultraestrutura , Eritrócitos/parasitologia , Animais , Babesia bovis/ultraestrutura , Bovinos , Membrana Eritrocítica/parasitologia , Eritrócitos/ultraestrutura , Interações Hospedeiro-Parasita , Microscopia Confocal/veterinária
7.
In. Llop Hernández, Alina. Microbiología y parasitología médica. Tomo.III. La Habana, Ecimed, 2001. .
Monografia em Espanhol | CUMED | ID: cum-56279
8.
Mol Biochem Parasitol ; 69(2): 149-59, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7770080

RESUMO

A Babesia bovis merozoite protein, Bb-1, was localized by immunoelectron microscopy to an apical organelle known as the spherical body. This unique structure appears to be analogous to dense granules of other apicomplexan protozoa. Similar to previously described dense granule proteins of Plasmodium spp., Bb-1 is secreted during or just after invasion of host erythrocytes and becomes associated with the cytoplasmic face of the infected cell. The amino terminal sequence of Bb-1 contains a predicted signal peptide and is similar to the amino terminus of another spherical body protein (BvVA1/225) which is also translocated to the erythrocyte membrane. Importantly, these two spherical body proteins are the major components of a protective fraction of B. bovis antigen. There is marked conservation of Bb-1 amino acid sequences and B-lymphocyte epitopes among geographic strains. However, a divergent Bb-1 allele (Bv80) in Australia strains encodes six regions of amino acid polymorphism, including a region of tetrapeptide repeats in the C-terminal half of the polypeptide. Two of the polymorphic regions map to previously defined Th1 epitopes on Bb-1.


Assuntos
Babesia bovis/genética , Babesia bovis/imunologia , Proteínas de Protozoários/genética , Proteínas de Protozoários/imunologia , Alelos , Sequência de Aminoácidos , Animais , Antígenos de Protozoários/genética , Antígenos de Protozoários/metabolismo , Babesia bovis/ultraestrutura , Clonagem Molecular , Imunofluorescência , Genes de Protozoários , Microscopia Imunoeletrônica , Dados de Sequência Molecular , Organelas/imunologia , Organelas/ultraestrutura , Proteínas de Protozoários/metabolismo , Homologia de Sequência de Aminoácidos
10.
Braz J Med Biol Res ; 27(11): 2591-8, 1994 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7549981

RESUMO

1. We describe the isolation of viable merozoites from erythrocytes infected with Babesia bovis or Babesia bigemina organisms by ammonium chloride lysis. 2. Parasite morphology was examined by both light and transmission electron microscopy. Erythrocyte-free parasites maintain their viability and infectivity, retain their antigenicity and are suitable for use in the indirect fluorescent antibody assay.


Assuntos
Babesia bovis/isolamento & purificação , Babesia/isolamento & purificação , Eritrócitos/parasitologia , Cloreto de Amônio , Animais , Anticorpos Antiprotozoários/análise , Babesia/imunologia , Babesia/ultraestrutura , Babesia bovis/imunologia , Babesia bovis/ultraestrutura , Bovinos , Imunofluorescência , Microscopia Eletrônica
11.
Braz. j. med. biol. res ; 27(11): 2591-8, Nov. 1994. ilus
Artigo em Inglês | LILACS | ID: lil-153980

RESUMO

1. We describe the isolation of viable merozoites from erythrocytes infected with Babesia bovis or Babesia bigemina organisms by ammonium chloride lysis. 2. Parasite morphology was examined by both light and transmission electron microscopy. Erythrocyte-free parasites maintain their viability and infectivity, retain their antigenicity and are suitable for use in the indirect fluorescent antibody assay


Assuntos
Animais , Bovinos , Babesia bovis/isolamento & purificação , Babesia/isolamento & purificação , Eritrócitos/parasitologia , Anticorpos Antiprotozoários/análise , Babesia bovis/imunologia , Babesia bovis/ultraestrutura , Babesia/imunologia , Babesia/ultraestrutura , Cloreto de Amônio/farmacologia , Imunofluorescência , Microscopia Eletrônica
12.
J Parasitol ; 79(2): 233-7, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8459334

RESUMO

Babesia bovis cultured in bovine erythrocytes was passaged into white-tailed deer (Odocoileus virginianus) erythrocytes and medium containing either white-tailed deer serum or bovine serum. Deer erythrocytes supported the growth of the parasite only in the presence of bovine serum. Cryopreserved cultures were recovered successfully in white-tailed deer erythrocytes. By light and electron microscopy, B. bovis structure appeared similar in host cells of either species.


Assuntos
Babesia bovis/crescimento & desenvolvimento , Cervos/sangue , Eritrócitos/parasitologia , Animais , Babesia bovis/ultraestrutura , Preservação de Sangue/veterinária , Bovinos , Células Cultivadas , Criopreservação/veterinária , Meios de Cultura , Eritrócitos/ultraestrutura , Masculino , Microscopia Eletrônica
13.
Int J Parasitol ; 22(2): 165-71, 1992 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1587679

RESUMO

A variety of anti-mitochondrial drugs that had previously been found to inhibit the growth of the malarial parasite Plasmodium falciparum were tested on Babesia bovis in vitro. Several of these drugs were found to be non-toxic towards B. bovis. However, those drugs that were found to inhibit babesial growth included compounds (shown in parentheses) that have the following putative mitochondrial targets in the parasite: ATP synthetase complex (rhodamine 123, oligomycin, Janus Green); ATP-ADP translocase (bongkrekic acid); electron transport (rotenone, n-heptyl-4-hydroxyquinoline-N-oxide (HQNO), antimycin A); ubiquinone (CoQ) function (BW58C, menoctone); protein synthesis (tetracycline); and the proton pump (CCCP). We have also investigated the effects of some of these drugs on pyrimidine biosynthesis de novo by following the incorporation of [14C]bicarbonate into pyrimidine nucleotides and into the pyrimidine moieties of nucleic acids. The ubiquinone analogues BW58C and menoctone inhibited this pathway in the nM-microM range of concentrations. Inhibitors of electron transport (antimycin A and oligomycin) and an uncoupler (CCCP) were also effective inhibitors of pyrimidine biosynthesis de novo. We conclude that B. bovis has a functional mitochondrion that contributes significantly to pyrimidine biosynthesis de novo and to the overall energy metabolism of the parasite.


Assuntos
Babesia bovis/ultraestrutura , Mitocôndrias/fisiologia , Animais , Babesia bovis/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos
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