Prepartum body conditions affect insulin signaling pathways in postpartum adipose tissues in transition dairy cows.

BACKGROUND: Overconditioned dairy cows are susceptible to excessive lipolysis and increased insulin resistance during the transition period. The associations among body fat reserve, insulin resistance, and lipolysis in adipose tissues (AT) remain to be elucidated. Therefore, this study aimed to investigate whether excessive fat reserves influence the insulin signaling pathway in AT postpartum. RESULTS: Twenty multiparous dairy cows were selected and assigned to one of two groups, according to prepartum body condition score (BCS): Control group (BCS = 3.0-3.5; n = 10) and Overconditioned group (BCS ≥ 4.0; n = 10). Blood samples were collected on days -14, -7, -4, -2, -1, 0, 1, 2, 4, 7, and 14 relative to parturition. Subcutaneous AT were collected on day 2 following parturition for quantitative real-time polymerase chain reaction and western blot analyses. No differences were observed between the two groups in serum glucose, non-esterified fatty acids, ß-hydroxybutyric acid, tumor necrosis factor (TNF) α, insulin, or leptin concentrations during the experimental period. Compared with the control cows, the overconditioned cows had lower serum triglyceride levels and higher adiponectin concentrations. In the AT postpartum, insulin receptor mRNA and protein levels were lower in the overconditioned cows than in the control cows, and no differences were found in glucose transporter 4 mRNA. Compared with the control cows, the overconditioned cows had lower mRNA levels of TNFα and higher mRNA levels of peroxisome proliferator-activated receptor gamma (PPARγ) in AT postpartum. The phosphorylated protein kinase B (AKT) content and phosphorylation rate of AKT were increased in the overconditioned cows compared with the control cows, which suggested that the downstream insulin signaling in AT was affected. CONCLUSIONS: In the present study, transition dairy cows with higher BCS did not show more fat mobilization. The changes of insulin signaling pathway in AT postpartum of overconditioned cows may be partly related to the expression of PPARγ and TNFα, and the secretion of adiponectin.

Mitochondrial genome of the Emberiza cioides (Emberizidae: Emberiza).

Emberiza cioides is a passerine bird of eastern Asia which belongs to the genus Emberiza in the bunting family Emberizidae. The complete mitochondrial genome of E. cioides was obtained for the first time. The circular genome (16,765 bp in length) consists of 37 typical animal mitochondrial genes (13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes) and 1 control region. Except for 8 tRNA genes and ND6 gene, all the genes were distributed in plus strand which were identical to those of most vertebrates.

Mitochondrial genome of the black-faced bunting (Emberiza spodocephala).

Black-faced bunting (Emberiza spodocephala) is a common small songbird with widely geographical range. In this study, the complete mitochondrial genome of the Emberiza spodocephala was determined. The study showed that the total length of the mitogenome was 16,796 bp as a circular DNA consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region (CR). Overall base composition of the complete mitochondrial DNA was 29.81% A, 23.12% T, 32.51% C, and 14.56% G. The CR is 1215 bp in length and was located between the tRNA(Gln) and tRNA(Phe) genes. The mitochondrial genes from Emberiza spodocephala were overlapped in a total of 29 bp at 6 locations, as well as interleaved with a total of 96 bp intergenic spacers at 18 locations.

Mitochondrial genome of the Emberiza pusilla (Emberizidae: Emberiza).

The Emberiza pusilla is a common bunting with very wide geographical range. Here, the complete mitochondrial genome of E. pusilla (16,790 bp in length) has been analyzed for building the database. The results showed that it consisted of 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 control region. The base composition of mtDNA was A (29.6%), G (14.8%), C (32.8%), and T (22.9%), so the percentage of A and T (52.5%) was slightly higher than G and C. All the genes in E. pusilla were distributed on the H-strand, except for the ND6 subunit gene and 10 tRNA genes, which were encoded on the L-strand.

Genetic structure of the oriental white stork (Ciconia boyciana): implications for a breeding colony in a non-breeding area.

The oriental white stork (Ciconia boyciana) is a threatened species, and their numbers are still in decline due to habitat loss and poaching. China is a breeding and main wintering area for this animal and in recent years some individuals have been found breeding in wintering areas and at some stopover sites. These new breeding colonies are an exciting sign, however, little is understood of the genetic structure of this species. Based on the analysis of a 463-bp mitochondrial DNA (mtDNA) control region, we investigated the genetic structure and genetic diversity of 66 wild oriental white storks from a Chinese population. We analyzed the sequences of 66 storks obtained in this study and the data of 17 storks from a Japanese population. Thirty-seven different haplotypes were detected among the 83 samples. An analysis of molecular variance showed a significant population subdivision between the two populations (F(ST) = 0.316, P < 0.05). However, the phylogenetic analysis revealed that the samples from the different populations did not form separate clusters and that there were genetic exchanges between the two populations. Compared with the Japanese population, the Chinese population had a relatively higher genetic diversity with a haplotype diversity (hπ SD) of 0.953 ± 0.013 and a nucleotide diversity (π± SD) of 0.013 ± 0.007. The high haplotype diversity and low nucleotide diversity indicate that this population might be in a rapidly increasing period from a small effective population. A neighbor-joining tree analysis indicated that genetic exchange had occurred between the newly arisen southern breeding colony and the northern breeding colony wintering in the middle and lower Yangtze River floodplain. These results have important implications for the conservation of the oriental white stork population in China.