The contribution of transposable elements to Bos taurus gene structure

In an effort to identify the contribution of TEs to bovine genome evolution, the abundance, distribution and insertional orientation of TEs were examined in all bovine nuclear genes identified in sequence build 2.1 (released October 11, 2005). Exons, introns and promoter segments (3 kb upstream the transcription initiation sites) were screened with the RepeatMasker program. Most of the genes analyzed contained TE insertions, with an average of 18 insertions/gene. The majority of TE insertions identified were classified as retrotransposons and the remainder classified as DNA transposons. TEs were inserted into exons and promoter segments infrequently, while insertion into intron sequences was strikingly more abundant. The contribution of TEs to exon sequence is of great interest because TE insertions can directly influence the phenotype by altering protein sequences. We report six cases where the entire exon sequences of bovine genes are apparently derived from TEs and one of them, the insertion of Charlie into a bovine transcript similar to the zinc finger 452 gene is analyzed in detail. The great similarity of the TE-cassette sequence to the ZNF452 protein and phylogenetic relationship strongly suggests the occurrence of Charlie 10 DNA exaptation in the mammalian zinc finger 452 gene. (c) 2006 Published by Elsevier B.V.

Constituintes sangüíneos de bovinos lactantes, desmamados e adultos das raças Nelore (Bos indicus) e Holandesa (Bos taurus) e de bubalinos (Bubalus bubalis) da raça Murrah

Blood samples from lactating, weaned and adult Holstein-Fresiean and Nelore cattle and Murrah buffaloes were tested through the study of hemogram and serum constituents. Red cell and leukocyte counts, and blood pH, fibrinogen, glucose, calcium, and phosphorus levels were similar in cattle and buffalo. Total protein, urea, creatinine, hemoglobin, magnesium, iron and aspartato aminotransferase and alanine aminotransferase activities were higher in buffalo than cattle. Leukocyte counts were higher for weaned Holstein cattle than for Nelore cattle but similar to buffalo and Nelore cattle had the lowest neutrophil counts. Bilirrubin levels were lower for buffalo than for cattle. Phosphatase alkalyne activities were lower for weaned buffalo than for other animals. Gammaglutamyltransferase activities were the highest for lactating and weaned buffalo.

Influence of sire breed (Bos indicus versus Bos taurus) and interval from slaughter to oocyte aspiration on heat stress tolerance of in vitro-produced bovine embryos

Based on in vitro experiments, Bos indicus embryos were more resistant to heat stress (HS) than Bos taurus embryos. To increase knowledge regarding differences between Bos indicus and Bos taurus in resistance to HS, the primary objective of this study was to determine if tolerance to HS is due to the breed, origin of the oocyte, sperm, or both. Additionally, the influence of the interval between ovary acquisition (in the abattoir) and oocyte aspiration in the laboratory, on early embryo development was ascertained. Oocytes were collected from Nelore and Holstein cows in an abattoir; 4.0 or 6.5 h later, oocytes were aspired in the laboratory, and then matured and fertilized using semen from Nelore (N), Gir (GIR), or Holstein (H) bulls. Ninety-six h post insemination (hpi), embryos with >= 16 cells were divided in two groups: control and HS. In the control group, embryos were cultured at 39 degrees C, whereas in the HS group, embryos were subjected to 41 degrees C for 12 h, and then returned to 39 degrees C. Rates of cleavage, and formation of morula and blastocysts were higher (P < 0.05) for oocytes aspirated at 4.0 versus 6.5 h after ovaries were acquired. Heat stress decreased rates of blastocyst formation for all breeds (N X N; H x H; and H X GIR) and in both time intervals (4.0 and 6.5 h). However, N X N had higher cleavage rate (P < 0.05) in both time intervals when compared with H X H and H X GIR. In addition, Nelore oocytes fertilized with Nelore semen (N X N) had higher blastocyst yields (P < 0.05) in the control and HS group, when compared with the other two breeds (H X H and H X GIR). We concluded that the breed of origin of the oocyte was more important than that of the sperm for development of thermotolerance, because bull breed did not influence embryo development after HS, and in vitro early embryonic development was impaired by increasing (from 4 to 6.5 h) the interval between ovary acquisition and oocyte aspiration. (C) 2011 Elsevier B.V. All rights reserved.

Immotile Short-Tail Sperm Defect in Nelore (Bos taurus indicus) Breed Bulls

ContentThis case study reported the presence of short tail sperm defect in the semen of three Nelore breed bulls. The sperm presented 0% of motility in the three animals evaluated and a total of 70%, 61% and 34% of pathologies of the intermediate piece of the tail respectively for animals 1, 2 and 3. It was identified that animals 2 and 3 had high degree of inbreeding, although no relationship was found with animal 1. Animal 2 was the only one that presented inbreeding coefficient (6.25%). His half-sib (animal 3) and animal 1, from the same herd, had shown no inbreeding, showing that inheritance is not the only determinant factor for its incidence on Nelore males.

Influence of the breed of bull (Bos taurus indicus vs. Bos taurus taurus) and the breed of cow (Bos taurus indicus, Bos taurus taurus and crossbred) on the resistance of bovine embryos to heat

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synaptonemal complex analysis of Nellore and Gyr breeds of Bos taurus indicus

A synaptonemal complex (SC) study of specimens of Nellore and Gyr breeds of Bos taurus indicus was performed with the main objective to identify and determinate the frequency of abnormalities of SC and the frequency of cells with abnormalities. All animals analyzed had 29 autosomal bivalents and one sexual bivalent. The Nellore breed had 30.00% of cells with SC abnormalities while the Gyr breed had only 11.11%. Statistical analyses showed that there were not significant differences for the number of cells with abnormalities among the breeds studied. The subspecies Bos taurus indicus had 16.92% of cells showing abnormalities, being 62.82% of these abnormalities in zygotene and 37.18% in pachytene. Some aspects regarding the frequency of cells with abnormalities and the fertility of Nellore and Gyr breeds are discussed.