[Show abstract][Hide abstract] ABSTRACT: Hypoxia can affect energy metabolism. We examined gene expression and enzyme activity related to mitochondrial energy metabolism, as well as myosin heavy chain (MyHC) types in yaks (Bos grunniens) living at high altitudes. Real-time quantitative PCR assays indicated that the yak has significantly lower levels of carnitine palmitoyltransferase (CPT) mRNA in the biceps femoris and lower levels of uncoupling protein 3 (UCP3) mRNA in both biceps femoris and longissimus dorsi than in Yellow cattle. No significant differences between yak and Yellow cattle were observed in the activities of mitochondrial β-hydroxyacyl-CoA dehydrogenase, isocitrate dehydrogenase and cytochrome oxidase in the same muscles. Semi-quantitative RT-PCR analysis showed that the MyHC 1 mRNA levels in yak biceps femoris was lower than in Yellow cattle. We conclude that the yak has significantly lower mRNA levels of CPT, UCP3, and MyHC 1 in biceps femoris than in Yellow cattle, suggesting that the yak biceps femoris has lower fatty acid oxidation capacity and greater glycolytic metabolic potential.
[Show abstract][Hide abstract] ABSTRACT: The objective of the present study was to reveal the characteristics of diacylglycerol O-acyltransferase 1 (DGAT1) gene of high altitude yak (Bos grunniens). Two mRNA sequences of yak DGAT1, including a full length and a spliced isoform deleted with 66 nucleotides in exon VIII, were cloned from Jiulong yak liver by reverse transcription polymerase chain reaction (RT-PCR). The coding sequence (CDS) of yak full length DGAT1 gene is 1470 bp, sharing 99.5% of nucleotide sequence homology and 100% of amino acid sequence homology with those of cattle, respectively. PCR analysis using DNA and RNA as templates demonstrated the alternative splicing of yak DGAT1 gene and estimated the proportion of the spliced isoform as approximately 30% of the total DGAT1 mRNA in yak liver and biceps femoris. Quantitative real-time RT-PCR analysis showed that both adult yak and cattle had significantly higher DGAT1 mRNA level in liver and adipose tissue than in skeletal muscles (P < 0.05), while no difference was observed between the corresponding tissues of yak and cattle, suggesting that yak DGAT1 gene might not be responsible for the lower intramuscular fat content in yaks compared to cattle. Allelic variation at nucleotide positions 10433 and 10434 (K232A) of the DGAT1 gene of yak and cattle was detected by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method. Nearly all yaks (n = 81) examined were homozygous for the K allele, while Chinese Holstein cows showed high frequency for the A allele. The K allele of yak DGAT1 gene might be correlated with its higher milk fat content characteristic.
[Show abstract][Hide abstract] ABSTRACT: The objective of the present study was to reveal the differences between yak (Bos grunniens) and cattle in energy metabolic characteristics and gene expressions in skeletal muscles. Activities of lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and β-hydroxyacyl-CoA dehydrogenase (HOAD), which are involved in metabolism of carbohydrate and fatty acid respectively, were measured in longissimus dorsi and biceps femoris. Yak contained higher total LDH activity and higher proportion of LDH5 in longissimus dorsi than cattle (P
[Show abstract][Hide abstract] ABSTRACT: Zheng, Y.C., Lin, Y.Q., Xu, Y.O., Wang, G.S., Jin, S.Y. and Li, Y.P. 2010. Enzyme activities and gene expression of yak skeletal muscles. J. Appl. Anim. Res., 38: 135–138.The purpose of the present study was to characterize the metabolic enzyme activities and gene expression levels in yak skeletal muscles. Yak longissimus dorsi had higher lactate dehydrogenase (LDH) activity, lower activities ofmalate dehydrogenase (MDH), β-hydroxyacyl-CoA dehydrogenase (HOAD) and cytocrome c oxidase (COX) compared with biceps femoris. Meanwhile, native PAGE of muscle extracts revealed that longissimus dorsi had higher proportion of LDH5 compared with biceps femoris. These data indicate the less oxidative metabolic orientation of yak longissimus dorsi. Semi-quantitative RT-PCR analysis revealed no significant difference in the expression of four genes including adipocyte fatty acid-binding protein (A-FABP), peroxisome proliferator-activated receptor gamma 2 (PPARγ2), myosin heavy chain 1 (MyHC1) and peroxisome proliferator-activated receptor coactivator lα (PGC-1α) between yak longissimus dorsi and biceps femoris.
Journal of Applied Animal Research - J APPL ANIM RES. 01/2010; 38(1):135-138.