抗菌肽LL-37在毕赤酵母SMD1168中的高效表达及活性鉴定

为获得高效表达的抗菌肽LL-37,根据人源抗菌肽LL-37的氨基酸序列,选择毕赤酵母(Pichia pastoris)密码子的偏嗜性,通过SOEing法改造合成LL-37基因片段,克隆到pGAPZαA质粒中,获得分泌型重组酵母表达载体pGAPZαA-LL-37。pGAPZαA-LL-37通过限制性内切酶AvrII酶切线性化后,经电穿孔法转入毕赤酵母细胞SMD1168。经Zeocin抗性筛选,得到高拷贝转化子,PCR检测表明LL-37基因与毕赤酵母染色体稳定结合。在GAP启动子调控下,LL-37蛋白获得分泌表达,其上清表达量约为237mg/L。表达产物耐热性强,在100℃条件下30min内仍保持一定的抗菌活性。表达产物对大肠杆菌DH5α、大肠杆菌D31和猪链球菌的最小抑菌浓度(MIC)分别为1.56μg/mL、3.12μg/mL和6.25μg/mL。     

Reproductive and developmental toxicity evaluation of a purified Arabinogalactan-Protein (AGP) composition in Wistar rats

A purified Arabinogalactan-Protein composition (LL-4218) was prepared from the leaves of Argemone mexicana to treat psoriasis. The effect of (LL-4218) was evaluated on reproductive (male and female fertility) and developmental toxicity in rats. LL-4218 was administered orally at the doses of 250, 500 and 1000 mg kg^− 1. The results showed that LL-4218 did not produce any significant dose related changes in reproductive and developmental toxicity studies. Therefore, it is concluded that LL-4218 did not produce any significant toxic effect on reproduction and developmental parameters of rats and NOAEL for reproductive and developmental toxicity studies in rats was 1000 mg kg^− 1.     

简便高效的蛋白质双相氯胺-T碘标法的建立及其应用

对双相氯胺-T碘标法实验装置作了改进并标记长效促红细胞生成素(LL-EPO),采用离心超滤技术代替传统的柱层析脱盐纯化标记蛋白质。结果显示125I-LL-EPO具有高比活性、高生物活性、高回收率。说明双相氯胺-T碘标法简单方便,是蛋白质同位素碘标记的理想方法;离心超滤技术适合放射性碘标记蛋白质的纯化。     

优质高产杂交早稻新组合吉优4218的选育与应用

介绍吉优4218的选育经过,分析其特征特性,总结其栽培技术、制种技术,以促进该品种的推广种植。