A novel carbonyl reductase from Pichia stipitis for the production of ethyl (S)-4-chloro-3-hydroxybutanoate

An NADPH-dependent carbonyl reductase (PsCR) gene from Pichia stipitis was cloned. It contains an open reading frame of 849 bp encoding 283 amino acids whose sequence had less than 60% identity to known reductases that produce ethyl (S)-4-chloro-3-hydroxybutanoates (S-CHBE). When expressed in Escherichia coli, the recombinant PsCR exhibited an activity of 27 U/mg using ethyl 4-chloro-3-oxobutanoate (COBE) as a substrate. Reduction of COBE to (S)-CHBE by transformants in an aqueous mono-phase system for 18 h, gave a molar yield of 94% and an optical purity of the (S)-isomer of more than 99% enantiomeric excess.     

新疆玛纳斯热气泉免培养土壤细菌多样性分析

【目的】了解新疆玛纳斯热气泉土壤免培养细菌群落组成及多样性。【方法】采用免培养法直接从土壤样品中提取总DNA,利用细菌通用引物对土壤总DNA进行16S rDNA扩增,构建细菌16SrDNA文库。使用HaeⅢ限制性内切酶对阳性克隆进行限制性片段长度多态性分析(restriction fragment length polymorphism,RFLP),挑选具有不同酶切图谱的克隆进行测序、比对并构建16SrDNA系统发育树。【结果】从土壤细菌16S rDNA文库中随机挑选了170个阳性克隆,共得到29个不同的分类单元(operational taxonomic unit,OTU)。系统发育分析归为6个门:酸杆菌门(Acidobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)和浮霉菌门(Planctomycetes)。其中厚壁菌门(Firmicutes)为绝对优势类群,占整个细菌文库的71%。29个OTUs中有14条序列与GenBank中相关序列的相似性低于97%(序列长度约1.5kb),占序列总数的48%。【结论】热气泉土壤细菌种群多样性较低,但存在大量潜在细菌新种。     

用复合PCR检测淋球菌、沙眼衣原体和解脲支原体的感染研究

在性传播疾病中,泌尿生殖道感染的主要病原体是淋球菌、沙眼衣原体和解脲支原体,目前临床上常有多种病原体混合感染[1],其临床症状相似或无明显症状,给确诊和治疗带来不便。因此我们应用多重引物ＰＣＲ(ｍｕｌｔｉｐｌｅｘＰＣＲ),一次实验能从临床标本中检测出三种病原体...     

Comparative Effects of Hispidulin,Genistein, and Icariin with Estrogen on Bone Tissue in Ovariectomized Rats

Icariin, Genistein, and Hispidulin have been proven to have estrogen-like and antiosteoporotic activity and can be potentially used for the treatment of osteoporosis. The present study found that Icariin, Genistein, and Hispidulin treatments, emulating estrogen, significantly contributed to bone density. Comparative effects of Icariin, Genistein, and Hispidulin with estrogen on in ovariectomized rats were investigated. Our results showed that genistein was found to have superior bone protective effects against osteoporosis among genistein, Icariin, and Hispidulin.     

The effects of feeding by the rice water weevil, Lissorhoptrus oryzophilus Kuschel, on the growth and yield components of rice, Oryza sativa

Abstract 1 The effects of feeding by larvae of the rice water weevil, Lissorhoptrus oryzophilus Kuschel, on the growth and yield components of rice, Oryza sativa, were evaluated using four varieties of rice, ‘Cocodrie’, ‘Cypress’, ‘Bengal’ and ‘XP1003’, over 2 years. 2 Both adults and larvae of L. oryzophilus feed on rice plants, but it is feeding by the larval stage that causes economic losses. Feeding by L. oryzophilus larvae resulted in extensive damage to root systems. Pruning of root systems resulted in a decrease in tiller number and shoot biomass of rice plants in the vegetative stage of growth. 3 Yield losses were due to a combination of decreases in panicle densities, numbers of grains per panicle, and grain weights. Decreases in panicle densities were a direct result of the reductions in tiller numbers. Reductions in numbers of grains per panicle and grain weights probably resulted from decreases in shoot biomass. 4 Injury by rice water weevil larvae is chronic. The tillering stage of rice suffered the majority of weevil damage, but the growth effects were not manifested until later.     

组胺对大鼠小脑皮层浦肯野细胞的兴奋作用

在离体大鼠小脑脑片上观察了组胺对小脑皮层第Ⅹ小叶浦肯野细胞的作用。组胺（３～１００μｍｏｌ／Ｌ）主要引起浦肯野细胞的兴奋反应（９４４％,５１／５４）,在少数细胞上也观察到组胺所引起的放电抑制现象（５６％,３／５４）。用低Ｃａ２＋／高Ｍｇ２＋人工脑脊液灌流脑片,不能取消浦肯野细胞对组胺的兴奋反应（ｎ＝４）。Ｈ２受体对抗剂ｒａｎｉｔｉｄｉｎｅ（０１～５μｍｏｌ／Ｌ）能够阻断浦肯野细胞对组胺的兴奋反应（ｎ＝２０）,而Ｈ１受体对抗剂ｔｒｉｐｒｏｌｉｄｉｎｅ（０５～５μｍｏｌ／Ｌ）不能够（ｎ＝９）或仅轻微地（ｎ＝４）阻断浦肯野细胞对组胺的兴奋反应。这些结果提示,组胺可能主要通过Ｈ２受体的介导对浦肯野细胞起兴奋性调节作用,下丘脑小脑组胺能神经通路可能参与了小脑的某些躯体的和非躯体的功能调节。