Signal transduction molecules AKT-1 and mTOR were essential for milk protein gene transcription and translation in mammary epithelial cells.Insulin,dexamethasone and prolactin composed of prolactin complex(DIP),the variety of lactation signal pathway activation was a necessary condition,including AKT-1/mTOR.In this study,the qRT-RCR and Western blotting were used to test above-mentioned two genes's expression level of mRNA and protein in different time points.The results showed that IGF-Ⅰ promoted significantly the expression levels of mRNA and protein for AKT-1 gene in the basis of DIP compared to the absence of IGF-Ⅰ(P0.05),and it also promoted significantly the expression of mTOR gene in mRNA and protein levels(P0.05).

By adding different concentrations of dipeptides: methionine-methionine,lysine-lysine,methionine-lysine,lysine-methionine,CASY-technology was used to study the proliferation and viability,and beta-casein gene expression were detected by qRT-PCR and HPLC of bovine mammary epithelial cells.The optimum concentrations of dipeptides were 80,100,50,80 μg.mL-1 at cultured 24 h,respectively.The proliferation of cells at optimum concentration were 1.28 × 105,1.66 × 105,1.79 × 105,1.85 × 105 cells.mL-1,respectively.And viabilities were 93.72%,95.59%,94.35%,95.65%,respectively.β-casein in culture medium at optimum concentration were 1.34,1.38,1.44,1.63 mg.10-5cells,respectively.These data provide further experimental evidence to further improve milk protein yield and milk protein synthesis.

Lysine is a restrictive essential amino acid of livestock, its content in feed directly affects livestock protein synthesis. In this research, the lysine- rich protein gene(cflr) was cloned from pepper anther, and connected with expression vector pHT43, the recombinant plasmid pHT43/cflr was constructed.The recombinant plasmid was transferred into Bacillus subtilis, upon IPTG induction, mRNA of cflr was observed, and their has an obvious protein band by SDS- PAGE; The content of lysine was detected by HPLC, the content of lysine in recombinant bacterium rised by 16.05% than wild bacterium. This experiment provides research-basis for application of the recombined Bacillus subtilis as feed additive.

Milk proteins contain nearly all the essential amino acids for the human body,which have great nutritional value.Today,how to increase milk protein production and improve milk quality has become the focus of increasingly intensive studies on protein nutrition.This paper provides a review of the regulatory effect of nutrients on bovine milk protein synthesis.

Starting from the importance of inequality,taking model teaching and breakthrough teaching as discussion focus,this paper expects to make some useful discussion on the inequality teaching.