Longissimus dorsi muscle transcriptomic analysis of Yunling and Chinese simmental cattle differing in intramuscular fat content and fatty acid composition.

Intramuscular fat (IMF) content and fatty acid (FA) composition vary significantly across beef cattle breeds, which play an important role in taste and nutritional value. However, the molecular mechanisms underlying these phenotypic differences remain unknown. The present study compared meat quality traits between Yunling cattle and Chinese Simmental cattle. Yunling cattle showed a lower IMF content and proportion of monounsaturated fatty acids (MUFA), as well as higher proportions of saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA), and short-chain fatty acids (sc-FA) in the longissimus dorsi (LD) muscle than Chinese Simmental cattle. To further identify the candidate genes and pathways responsible for these phenotypic differences, the transcriptome of LD muscle from the two breeds were measured using RNA-seq. A total of 1347 differentially expressed genes were identified. The major metabolic pathways that were differentially modulated were lipolysis and glycometabolism. Yunling cattle showed a higher expression of lipolysis genes (ALDH9A1, ACSL5, ACADM, ACAT2, ACOT2) and a lower expression of genes related to glycometabolism (PGM1, GALM, PGM1, GPI, LDHA). This research identified candidate genes and pathways for IMF content and FA composition in the LD muscle of beef cattle, which may facilitate the design of new selection strategies to improve meat quality.

A new high-frequency allele of the BM2113 locus in the Yunnan mithun population.

The BM2113 locus was amplified in Yunnan mithun (Bos frontalis) from the southwest mountains of China. It showed a high degree of polymorphism with a total of 12 alleles. The 121-bp polymorphic allele of the BM2113 locus that accounted for 37.1% of homozygotes was the predominant allele with a frequency of 58.57%, identified as mithun-specific for Bos species in Yunnan mithun. The polymorphism information content value was high with a mean of 0.6170, the expected and observed heterozygosity was moderate with values of 0.6427 and 0.6000, respectively, and the BM2113 locus was under Hardy-Weinberg equilibrium (P = 0.2897) in the Yunnan mithun population. This study elucidated the genetic diversity, multi-origin, specific alleles, and characterization of mithun.

Association of bovine Toll-like receptor 4 with tick infestation rates and blood histamine concentration.

We investigated a possible association between bovine Toll-like receptor 4 (TLR4) and resistance to tick infestation in 103 cattle, including BMY cattle (1/2 Brahman, 1/4 Murray Grey, and 1/4 Yunnan Yellow cattle), Brahman, and Red Angus grazing on improved pasture. The tick infestation weight and number of Rhipicephalus microplus and the blood histamine concentration were measured and compared with those of 32 Chinese Holsteins and 30 Simmentals. A 228-bp fragment was amplified and sequenced to analyze the polymorphisms of the TLR4 gene. After SSCP and sequencing analysis, 4 SNPs, i.e., 535(A>C), 546(T>C), 605(T>A), and 618(G>C), were identified, corresponding to GenBank accession Nos. AY297041 and NW_003104150; the latter two SNPs caused Leu→Gln and Gln→His substitutions, respectively. Genotype AA was completely predominant in the Chinese Holstein and Simmental; genotypes AA and AB were detected in Red Angus, while genotypes AA, AB, BB, and BC were detected in Brahman and in BMY cattle. A negative correlation was identified between blood histamine concentration and number of tick infestation; in BMY cattle this negative association was significant. The tick infestation in cattle with genotype BB was significantly lower than in those with genotype AA. Blood histamine concentration in cattle with genotype BB was significantly higher than in those with genotype AA. The TLR4 gene mutation could affect the blood histamine level and activate the immune reaction after tick infestation. Allele B has potential as a molecular marker for tick-resistance originated from Zebu cattle for use in cattle breeding programs.

Genetic diversity analysis of BMY cattle based on microsatellite DNA markers.

BMY cattle (1/2 Brahman, 1/4 Murray Grey and 1/4 Yunnan Yellow cattle) has been inter se breeding since 1980s. Genetic diversity of BMY cattle was extensively investigated using 16 microsatellite markers. A total of 130 microsatellite alleles and high allele size variance were detected. All loci displayed high genetic diversity with overall mean of N(a) = 8.13, PIC = 0.7224 and H(e) = 0.7666, which were higher than those of many other beef breeds. The allele-sharing neighbour-joining tree clearly displayed the new genotypic combinations and the minglement from both BMY cattle and Brahman. The results provided the genetic information to match the standards of new beef breed in South China.

Karyotype analysis of mithun (Bos frontalis) and mithun bull x Brahman cow hybrids.

We examined the cytogenetics of mithun (Bos frontalis), a domesticated version of the Asian gaur, and hybrids (F(1) generation) produced by artificial insemination of Brahman cows (Bos indicus) with mithun semen. Reproductive potential was also examined in the F(1) generation and a backcrossed heifer for utilization of heterosis. Metaphase chromosome spreads were examined by conventional staining and fluorescence in situ hybridization hybridized with the entire chromosome 1 of mithun as a specific probe. Chromosome 1 of mithun was found to be equivalent to Bos taurus chromosomes 2 and 28. The karyotype of the female mithun (N = 4) comprised 58 chromosomes, including 54 acrocentric and four large submetacentric chromosomes, without the four acrocentric chromosomes found in the domesticated species B. indicus. However, one of the four female mithuns with a normal mithun phenotype had an abnormal karyotype (2n = 59), indicating introgression from B. taurus or B. indicus. The F(1) karyotypes (N = 6, 3♂3♀) of the mithun bull × Brahman cow cross had 2n = 59, intermediate between their parents; they were consistent heterozygous carriers with a centric fusion involving rob(2;28), as expected. Two pronounced red signals were seen in the mithun karyotypes, three red signals in the mithun × Brahman hybrids, and four red signals in the Brahman cattle, in good agreement with centric fusion of bovine rob(2;28). The female backcross hybrid (N = 1) with 2n = 59 had a similar chromosome configuration to the F(1) karyotypes and had rob(2;28). Such female backcross hybrids normally reproduce; however, the F(1) bulls (N = 3) had not yet generated normal sperm at 24 months.

Bone augmentation by recombinant human BMP-2 and collagen on adult rat parietal bone.

A composite of recombinant human bone morphogenetic protein-2 (rhBMP-2) and collagen was implanted beneath the cranial periosteum of 10-month-old rats to observe bone development and absorbent change of carrier collagen. The rhBMP-2/collagen onlay implant resulted in active bone formation and the augmented bone was connected directly with the original bone, whereas the collagen alone resulted in neither bone nor cartilage. The ossification process in the rhBMP-2/collagen occurred directly through bone formation, similar to intramembranous ossification. The carrier collagen fibers were found in the woven bone and were completely absorbed at 8 weeks in the presence of rhBMP-2, while the collagen alone implant remained encapsulated by a thin, fibrous connective tissue. Our results indicate that rhBMP-2/collagen is an effective material as a biological onlay implant, showing osteoinductive properties and being completely replaced by new bone. Carrier collagen not only plays a role in rhBMP-2 delivery, but also provides a cell anchorage for cell differentiation and remains as an artificial matrix in woven bone.

Studies on the transmission of human hepatitis A virus to stump-tailed monkey.

The newly-caught stump-tailed monkeys (Macaca speciosa) with negative antibody to hepatitis A were inoculated with human hepatitis A virus. The following findings were observed in the monkeys after inoculation: (i) the elevation of activities of the serum glutamic-pyruvic transaminase, lactate dehydrogenase and its isoenzyme (LDH5), (ii) the seroconversion of antibody to hepatitis A virus. (iii) the shedding of hepatitis A antigen in feces. These findings show that the stump-tailed monkey (Macaca speciosa) is susceptible to infection of human hepatitis A virus. The virus recovered from the feces of the infected monkey, named as Hang-zhou A-1A strain of hepatitis A virus, has experienced two generations of successful transmission in monkeys.

Susceptibility of monkeys to human hepatitis A virus.

A stump-tailed monkey, newly caught and without antibody to hepatitis B virus (HAV), was successfully infected with human HAV. The following alterations were observed in the monkey's functions: (1) elevation in activities of serum glutamic pyruvic transaminase, lactate dehydrogenase, and its type 5 isoenzyme (electrophoretically the fastest moving); (2) development of antibody to HAV; and (3) shedding of HAV antigen in feces. The virus isolated from the monkey, designated the Hangzhou A-1A strain of HAV, was serially transmitted to two other stump-tailed monkeys. Thus, the stump-tailed monkey (Macaca speciosa) is susceptible to infection with human HAV.

Patterns of shedding of hepatitis A virus antigen in feces and of antibody responses in patients with naturally acquired type A hepatitis.

Serial stools and sera from 13 patients with hepatitis A were collected during an epidemic in 1978 in a rural village near Hangzhou, China, and were studied to determine the patterns of shedding of hepatitis A antigen (HAAg) and of antibody response in some cases. Of 44 stool specimens, 31 were HAAg-positive by a radioimmunoprecipitation-polyethylene glycol assay. The highest percentage of HAAg positivity was in stools collected one week before and one week after the peak elevation of serum glutamic pyruvic transaminase (SGPT) levels, and peak HAAg shedding in each patient usually occurred in the early stools. Fecal shedding of HAAg was detected as early as day 19 before peak elevation in SGPT level and as late as day 11 afterward and continued for at least 25 days. The pattern of HAAg shedding in feces and of complement-fixation and immune adherence antibody response in relation to the change in SGPT activity and jaundice in four patients with hepatitis A was demonstrated.