Effect of Metallothionein on Cell Cycle,Apoptosis Rate and Subsets Distribution of Lymphocytes in Peripheral Blood of Dairy Cattle under Heat Stress

[Objective]This study aimed to research the effect of metallothionein on cell cycle,apoptosis rate and subsets distribution of lymphocytes in peripheral blood of dairy cows under heat stress,so as to perfect the regulative mechanism researches of MT to anti-heat stress.[Method]Twenty lactating Chinese Holstein cows were randomly divided into four groups(A,B,C and D),and injected with 0,4.0,8.0 and 12.0 mg Zn-metallothionein,respectively by intravenous route.Blood samples were collected at 1st,16th,31st,46thand 61stday,and the dynamic changes of cell cycle,apoptosis rate and subsets distribution of lymphocytes were determined.[Result]The apoptosis rate of cells in group B and C was lower than those in group A by 26.63%(P>0.05)and 24.84%(P>0.05)respectively.The number of cells in the G0/G1phage in trial groups was increased and the number of cells in the S and G2/M phages tended to decrease,but there were no significant differences(P>0.05).The number of CD3+T cell in three trial groups was greater than those in group A by 7.02%(P>0.05),5.45%(P>0.05)and 3.85%(P>0.05)respectively,while the number of CD4+T cell in trial groups was higher than those in control group by31.04%(P<0.05),35.68%(P<0.05)and 39.34%(P<0.05)respectively.The number of CD8+T cell and the levels of CD4+/CD8+in trial groups were increased observably,but significant difference(P<0.05)was observed in the levels of CD4+/CD8+between groups A and C only.It demonstrated that exogenous Zn-metallothionein can decrease apoptosis rate,improve cell cycle and regulate subsets distribution of lymphocytes in dairy cattle in a dose-dependent manner.[Conclusion]This study will provide scientific basis for safe utilization of MT in dairy industry.

The Effects of Different Tillages on Crop Residue Sequestration, Soil Available Nutrients and Some Biochemical Properties in the Chinese Black Soil Region

Three-year field experiments were conducted to investigate the effects of different tillage operations after harvest on crop residues sequestration and their subsequent effects on soil available nitrogen （N）, phosphorus （P）, some soil biochemical properties, and three enzymatic activities during the following growing seasons in a soybean （Glycine max）-soybean- corn （Zea mays） rotation farming system in Northeast China. Two different managements were implemented after crop harvest every year, which were tillage （T） and no tillage （NT）. Results showed that crop residue masses on soil surface and in the 0-20 cm layer after soybean harvest were about 1 450 and 340 kg ha-1, respectively, in October 2006 and 2007. While, soybean residue mass in the 0-20 cm soil layer was about 340 kg ha-1 in NT and about 1 550 kg ha-1 in T before sowing in May 2007 and 2008. The adverse results were found after corn crop plantation, that corn residue mass was about 270 and 860 kg ha-1 on soil surface and in the 0-20 cm soil layer, respectively, after harvest in October 2008, while residue mass in the 0-20 cm soil layer was only 466 kg ha-1 in T but 863 kg ha-1 in NT before planting in May 2009. So T had effectively sequestered soybean residue into soil but not corn. Results also showed that T after harvest helped to improve soil available N, P, soil microbial biomass carbon （MBC）, and nitrogen （MBN） contents and soil enzymes activities （urease, acid phosphatase, and protease） during the 2007 and 2008 seasons, but the positive effects decreased during the 2009 season. T practice had significant positive effects on available N, P, MBC, and MBN contents, protease and urease activities, however, no obvious effects on acid phosphatase activity. In this study, T practice after soybean harvest was proved to be preferable to improve soil microbial and enzyme activities during the following seasons due to an efficient sequestration of soybean residues. However, NT could be considered preferential after corn crop harvest.

Exploring polyamines:Functions in embryo/fetal development

Polyamines such as putrescine, spermidine, spermine and agmatine are aliphatic polycationic compounds present in all living cells, and are derived from amino acids, intestinal bacteria, exfoliated enterocytes and supported from diet. Polyamines as the key compounds play essential role in cell proliferation, growth and differentiation. They also exert significant effects on embryonic development,implantation, embryonic diapause, placentation, angiogensis and fetal development. This review paper summarizes the functions of polyamines and embryo/fetus development and its regulatory mechanism which should help to provide some evidences for clinic.