The polymorphisms of κ-casein gene and their associations with milk production traits and expression analysis in Chinese Holstein cattle

The polymorphisms of exon 4 and 5 of κ-casein (CSN3) gene and their associations with milk production traits and expression pattern in Chinese Holstein cattle were investigated. Nine mutational sites, of which seven were novel mutational sites, were identified and genotyped by polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP), created restriction site-PCR (CRS-RFLP) and sequencing methods in 398 cows. Linkage disequilibrium analysis showed that SNP-1 (g.10891 T > C rs 43703015, g.10927 C > A rs 43703016, g.10988 G > A ss 256302464 and g.10966 A > T ss 256302465) and SNP-2 (g.12907 A > G ss 256302466, g.12950 G > A ss 256302468, g.12989 C > T ss 256302469 and g.13028 A > G ss 256302470) were completely linked, respectively. Correlation analysis showed that SNP-1, SNP-2 and SNP-3 (g.12980 T > C ss 256302467) markers were closely correlated to the fat content. The SNP-3 marker had a remarkable effect on the protein content (P < 0.05). 16 combined genotypes of the three SNPs were found. Fat and protein content in combinations of genotypes were varied significantly (P < 0.05). Genotypes BBCCEE and ABTCDD individuals had the highest fat and protein content, respectively, which may be useful for marker assisted selection program in dairy cattle. The expression of CSN3 mRNA in the mammary tissue was higher than that of in the liver tissue (P < 0.05) and the expression in the spleen of BB genotype was higher than that of AA genotype in the SNP-1 (P < 0.05) by fluorescent quantitation real-time PCR (Q-PCR) assay.Key words: SNPs, CSN3 gene, combined genotype, Q-PCR, milk production traits

Novel single nucleotide polymorphisms (SNPs) of the bovine STAT4 gene and their associations with production traits in Chinese Holstein cattle

Signal transducer and activator of transcription 4 (STAT4) belongs to the STATs family which may play important roles in the activation of milk protein genes and the development of mammary glands. Four novel single nucleotide polymorphisms (SNPs) (g.2624A>C ss175327225, g.60330A>G ss175327226, g.63823G>C ss175327227, g.66912C>T ss175327228) of the STAT4 gene were investigated in 966 cattle of three breeds (Chinese holstein, Luxi yellow and Bohai black cattle) in China by polymerase chainreaction-single-strand conformation polymorphism (PCR-SSCP), PCR-restriction fragment length polymorphism (RFLP) and DNA sequencing methods. The SNP (g.60330A>G ss175327226) could be genotyped into three genotypes (AA, AG and GG) with PCR-RFLP using Msp I and another SNP (g.66912C>T ss175327228) only into two genotypes (CC and TC) by PCR-SSCP. The allelic frequencies of the SNP (g.60330A>G) were different among the three different cattle breeds (P < 0.05). The associations between polymorphisms of the STAT4 gene and dairy performance traits were analyzed in 793 Chinese holstein cows. The SNP (g.60330A>G) markedly affected the 305 d matured equivalency (P < 0.05) and fat content (P < 0.05). However, the SNP (g.66912C>T) had no significant relationship with the milk production traits (P > 0.05). Together, the SNP (g.60330A>G) of the STAT4 gene may serve as a molecular marker for the differentiation of various cattle populations and selection of the milk yield and fat content in bovine breeding program

Tunable hybrid surface waves supported by a graphene layer

We study surface waves localized near a surface of a semi-infinite dielectric medium covered by a layer of graphene in the presence of a strong external magnetic field. We demonstrate that both TE-TM hybrid surface plasmons can propagate along the graphene surface. We analyze the effect of the Hall conductivity on the disper- sion of hybrid surface waves and suggest a possibility to tune the plasmon dispersion by the magnetic field.Comment: 3 pages, 3 figure

Plastic flow and failure resistance of metallic glass: Insight from \u3cem\u3ein situ\u3c/em\u3e compression of nanopillars

We report in situ nanocompression tests of Cu-Zr-Al metallic glass (MG) pillars in a transmission electron microscope. This technique is capable of spatially and temporally resolving the plastic flow in MGs. The observations reveal the intrinsic ability of fully glassy MGs to sustain large plastic strains, which would otherwise be preempted by catastrophic instability in macroscopic samples and conventional tests. The high ductility in volume-limited MGs and the sample size effects in suppressing the rapid failure common to MGs are analyzed by modeling the evolution of the collectivity of flow defects toward localization