ABSTRACT The results of a cytogenetic study carried out in two female Miniature Pinscher who died after birth, one affected with meningoencephalocele (MEC) and the other apparently normal, are presented. The analysis of 156 metaphases (75 of the specimen with pathology and 81 without pathology) showed a typical unimodal female complement 2n = 78 (76, XX) in 95.06% of all metaphases in the normal puppy, while the puppy with ECM showed a multimodal karyotype with three chromosomally distinct cell lines: 2n = 78 (36%); 77 (28%); 76 (10.67%). The remaining 25.33% of cells corresponded to cells with less than 76 chromosomes. Statistical analysis of the medians of the chromosome counts using the Man-Whitney U test between the normal (median = 78; median range = 51.81) and affected (median = 77; median range = 26.69) puppies revealed highly significant differences (p=2.8192x10-13). It was not possible to establish a pattern that would allow to identify a specific aneuploidy but it was possible to verify that the numerical variation affected both the sex chromosomes and those of the first large acrocentric complement pair, as well as other remaining chromosomal elements, which suggests the occurrence of random non-disjunction processes in the cells of the MEC-affected puppy. This result constitutes the first evidence of association between a case of MEC and chromosomal mosaicism in dogs.

RESUMEN Se presentan los resultados de un estudio citogenético realizado en dos hembras caninas de raza Pinscher Miniatura que murieron después de nacer, una afectada con meningoencefalocele (MEC) y la otra aparentemente normal. El análisis de 156 metafases (75 del ejemplar con patología y 81 sin patología) mostró un complemento femenino unimodal típico 2n = 78 (76, XX) en el 95.06% de todas las metafases en el cachorro normal, mientras que el cachorro con MEC mostró un cariotipo multimodal con tres líneas celulares cromosómicamente distintas: 2n = 78 (36%); 77 (28%); 76 (10.67%). El 25.33% de células restantes correspondió a células con menos de 76 cromosomas. El análisis estadístico de las medianas de los recuentos de cromosomas mediante la prueba U de ManWhitney entre el cachorro normal (mediana = 78; rango medio = 51.81) y afectado (mediana = 77; rango medio = 26.69) reveló diferencias altamente significativas (p=2.8192x10-13). No fue posible establecer un patrón que permitiera identificar una aneuploidía específica, pero se pudo verificar que la variación numérica afectó tanto a los cromosomas sexuales y a los del primer par acrocéntrico grande del complemento, así como también otros elementos cromosómicos restantes, lo cual sugiere la ocurrencia de procesos de nodisyunción aleatoria en las células del cachorro afectado con MEC. Este resultado constituye la primera evidencia de asociación entre un caso de MEC y mosaicismo cromosómico en perros.

As doenças infecciosas e parasitárias causam perdas importantes em vários setores da produção da pecuária mundial. Estima-se que mais de 600 milhões de bovinos de países tropicais e subtropicais estejam expostos à infecção por Babesia sp. gerando grande prejuízo econômico. Os gêneros Babesia e Plasmodium são hemoparasitas pertencentes ao filo Apicomplexa e apresentam características comuns no processo de invasão eritrocitária. A babesiose bovina causada por Babesia bigemina e Babesia bovis apresenta sinais clínicos similares a malária humana causada por Plasmodium vivax e Plasmodium falciparum. A glicoproteína Duffy é a única receptora para o P. vivax em humanos. A maioria dos indivíduos negros africanos é resistente a este parasita devido a uma mutação que provoca a ausência de expressão desta glicoproteína na superfície das hemácias. Tendo em vista este fato, e que animais da subespécie Bos taurus taurus são mais susceptíveis à babesiose quando comparados à animais Bos taurus indicus, objetivou-se neste trabalho a detecção e quantificação do antígeno Duffy na superfície dos eritrócitos de bovinos empregando para tal, anticorpo policlonal que permitisse investigar se as diferenças na susceptibilidade são devido a diferentes níveis de expressão do antígeno Duffy nas hemácias. Ensaios de ELISA mostraram que o anticorpo produzido foi capaz de reconhecer o antígeno Duffy presente nas hemácias bovinas e a análise quantitativa não demonstrou diferença significativa na presença do mesmo. Estes resultados sugerem que a resistência maior dos zebuínos à babesiose não se deve à ausência de expressão, ou à presença em menor quantidade do antígeno Duffy na superfície de suas hemácias.

Babesiosis is one of the most important diseases affecting livestock agriculture worldwide. Animals from the subspecies Bos taurus indicus are more resistant to babesiosis than those from Bos taurus taurus. The genera Babesia and Plasmodium are Apicomplexa hemoparasites and share features such as invasion of red blood cells (RBC). The glycoprotein Duffy is the only human erythrocyte receptor for Pasmodium vivax and a mutation which abolishes expression of this glycoprotein on erythrocyte surfaces is responsible for making the majority of people originating from the indigenous populations of West Africa resistant to P. vivax. The current work detected and quantified the Duffy antigen on Bos taurus indicus and Bos taurus taurus erythrocyte surfaces using a polyclonal antibody in order to investigate if differences in susceptibility to Babesia are due to different levels of Duffy antigen expression on the RBCs of these animals, as is known to be the case in human beings for interactions of Plasmodium vivax-Duffy antigen. ELISA tests showed that the antibody that was raised against Duffy antigens detected the presence of Duffy antigen in both subspecies and that the amount of this antigen on those erythrocyte membranes was similar. These results indicate that the greater resistance of B. taurus indicus to babesiosis cannot be explained by the absence or lower expression of Duffy antigen on RBC surfaces.

Within about 30 years the Brazilian buffalo (Bubalus bubalis) herd will reach approximately 50 million head as a result of the great adaptive capacity of these animals to tropical climates, together with the good productive and reproductive potential which make these animals an important animal protein source for poor and developing countries. The myostatin gene (GDF8) is important in the physiology of stock animals because its product produces a direct effect on muscle development and consequently also on meat production. The myostatin sequence is known in several mammalian species and shows a high degree of amino acid sequence conservation, although the presence of non-silent and silent changes in the coding sequences and several alterations in the introns and untranslated regions have been identified. The objective of our work was to characterize the myostatin coding regions of B. bubalis (Murrah breed) and to compare them with the Bos taurus regions looking for variations in nucleotide and protein sequences. In this way, we were able to identify 12 variations at DNA level and five alterations on the presumed myostatin protein sequence as compared to non double-muscled bovine sequences.