Effect of kinetin on immunity and splenic lymphocyte proliferation in vitro in D-galactose-induced aging rats / 生理学报

The purpose of this paper is to study the effect of kinetin (Kn) on immunity and splenic lymphocyte proliferation in vitro of aging rats induced by D-galactose (D-gal). Fifty SD rats were randomly divided into five groups: control group, aging model group, Kn low dose group, Kn middle dose group and Kn high dose group. The aging model group was proposed by napes subcutaneous injection of D-gal (125 mg/kg) for 45 d, and anti-aging groups were intragastrically administered with 5, 10, 20 mg/kg of Kn respectively from day 11. IgG, IgA, IgM contents of serum, the apoptosis percentage, stimulation index (SI) and proliferation index (PI) of splenic lymphocyte in vitro were evaluated. The results showed that the apoptosis percentage of splenic lymphocyte in aging model rats was higher, the serum IgG, IgA and IgM contents, SI and PI were lower than control group. Kn significantly decreased the apoptosis percentage of splenic lymphocyte, while increased the serum IgG, IgA and IgM contents, SI and PI in aging model group. These results suggest that Kn could inhibit the apoptosis, while promote the proliferation of splenic lymphocyte, and then effectively enhance the immune power of the aging rats and slow down the aging process.

Screening and Metabolic Flux Analysis of Glutathione-high-yielding Strain from Saccharomyces cerevisiae / 中国生物工程杂志

The zinc chloride and cystine resistant strain of S.cerevisiae YZM-14(ZnCl2r,Cysr) was screened with the mutant processing of the protoplast of S.cerevisiae by combinative mutagens of ultraviolet and nitrite.The glutathione(GSH) production(84.72 mg/L),dry cell weight(7.63 g/L) and the intracellular GSH content(11.10 mg/g) of YZM-14 were 2.79,1.63 and 1.71 times compared with that of the initial strain.The biosynthetic process of GSH was divided into three phases according to the time course of the specific cell growth rate and GSH yielding coefficient.In the second phase,the metabolic flux of the pentose phosphate pathway and the GSH precursors biosynthetic pathway of the mutant strain increased by 8.1 mmol/(g?h),compared with that of the initial strain.Furthermore,the metabolic flux of the organic acids secretion of the mutant strain decreased.Through these mechanisms,the utilization efficiency of the carbon sources was enhanced and high production of GSH was obtained.