圈卷产色链霉菌7100分化相关基因——sawE的结构与功能

以天蓝色链霉菌的whiB基因为探针,从圈卷产色链霉菌7100的总DNA部分文库中克隆了含有whiB同源序列的28kb DNA片段,并对其中的14kb片段进行了序列测定。序列分析表明,该片段含有一个完整的开放阅读框—sawE。预测的蛋白质结构及同源性分析显示,sawE与天蓝色链霉菌孢子形成早期的关键基因whiB高度同源,编码产物为一个调控蛋白。sawE的破坏使圈卷产色链霉菌7100的分化终止在气生菌丝阶段,在延长培养时间的情况下仍保持白色的表型,菌丝不能分隔,不能形成成熟的灰色孢子,结果表明sawE基因是一个与圈卷产色链霉菌分化有关的重要基因。     

腾冲嗜热菌单链 DNA 结合蛋白 SSB2 和 SSB3 新的单链 DNA 结合特性

摘要：【目的】揭示腾冲嗜热菌中两个单链DNA结合蛋白SSB2和SSB3的全新的底物结合功能及其不同的体内表达模式。【方法】利用腾冲嗜热菌复制起始位点附近的长度较短的单链DNA为底物,采用非变性聚丙烯酰胺凝胶电泳及western blot方法,研究SSB2和SSB3体外单链DNA结合特征和体内表达模式。【结果】SSB2 与35nt的复制起始区单链DNA（ssDNA）结合, 形成单个SSB2-DNA复合物;当与59 nt ssDNA结合时,可以随着蛋白浓度的递增形成一个或两个SSB2-DNA复合物;而与70n     

圈卷产色链霉菌硝基烷类氧化酶的分离纯化及酶学性质

圈卷产色链霉菌硝基烷类氧化酶基因naoA在大肠杆菌中获得了成功表达,从含有重组质粒pNA101(pET23b∷naoA)的工程菌株BL21(DE3)中分离纯化了硝基烷类氧化酶,SDSPAGE检测为均一。对纯酶进行了酶学性质及动力学研究。底物为1硝基丙烷、2硝基丙烷和硝基乙烷时,在04mol/L的磷酸缓冲液中,酶的最适反应pH值为7～8,最适反应温度为48℃～56℃。室温保存6d后,酶的活性保持了43.3%,但对60℃以上的高温敏感。硫醇化合物如巯基乙醇、还原型谷胱甘肽不同程度地抑制酶活性,特别是NADH,其浓度为1mmol/L时,酶活性几乎全部丧失。以1硝基丙烷为底物时,NaoA的Km为357mmol/L,Vmax为0199μmol/(μg.min)。     

河西走廊荒漠地区的人口和生态问题

甘肃省自然条件差,粮食自给程度低。在这一背景下,有着灌溉之利,粮食产量较高且稳定的河西走廊荒漠绿洲,便首当其冲地承受着生产更多商品粮的压力。由此必须扩大垦殖,增加用水以及由于人口增长而扩大樵采等对植被的破坏,加剧了沙漠化的发展和绿洲的衰退。本文拟对河西走廊荒漠地区的人口与生态环境问题及解决途径,做一概略讨论。     

链霉菌发育调控启动子——P_(TH270)对细胞分化的影响

在原核生物发育分化的分子生物学研究中,以枯草杆菌为模式系统进行了许多研究,但其生命周期特别是分化过程比较简单,不象链霉菌有基质菌丝、气生菌丝、菌丝分隔形成多细胞,然后断裂形成单孢子的过程。链霉菌的这一性状与真核生物丝状真菌的分化相似。因此在原核生物中,链霉菌是研究分化基因表达调控的良好模式材料,为在时空上研究发育分化基因的多水平调控提供了有利条件。 链霉菌的发育调控启动子(P_(TH270))是国际上首先克隆的两个启动子之一。一些研究结果表明该启动子依赖于链霉菌分化关键基因——whiG。虽然该启动子的序列已被测定,启动子的-10区和-35区已被精确定位,但该启动子在链霉菌发育分化中是如何调控的,当它以高拷贝数的形式存在时对细胞内含物的组份有何影响,这种影响怎样与分化关联,这些都是有待解决的重要问题。本文报道这方面     

lncRNA CASC11 promotes cancer cell proliferation in bladder cancer through miRNA-150

Long noncoding RNAs (lncRNAs) CASC11 is an oncogenic lncRNA in gastric cancer and colorectal cancer. Our study aimed to investigate the role of lncRNA CASC11 in bladder cancer. In this study we showed that plasma lncRNA CASC11 was upregulated, while plasma miRNA-150 was downregulated in patients with early-stage bladder cancer than in healthy controls. Altered expression of plasma lncRNA CASC11 and miRNA-150 separated patients with bladder cancer from healthy controls. lncRNA CASC11 expression was inversely correlated with miRNA-150 expression in patients with bladder cance but not in healthy controls. Overexpression of lncRNA CASC11 mediated the inhibition of miRNA-150 expression in cancer cells, while miRNA-150 overexpression did not significantly alter lncRNA CASC11 expression. lncRNA CASC11 overexpression promoted, while miRNA-150 overexpression inhibited cancer cell proliferation. miRNA-150 also attenuated the enhancing effects of lncRNA CASC11 overexpression on cancer cell proliferation. However, overexpression of lncRNA CASC11 showed no significant effects on cancer cell migration and invasion. Therefore, lncRNA CASC11 may promote cancer cell proliferation in bladder cancer, and the actions of lncRNA CASC11 are likely through miRNA-150.     

新疆北疆地区景观生态类型分类初探：以新疆沙湾县为例

1　前　　言新疆生态环境的现状喜忧参半,绿洲内部生态环境得到改善,但沙漠化过程不断加剧,成为新疆生态环境良性循环的极大隐患。景观生态学以综合整体的思想审视生态环境的现状和变化,为我们更成功地解决所面临的生态问题提供了新的理论和方法。本文试图在新疆沙湾县生态环境监测工作的基础上,提出适宜于新疆北疆地区的景观生态类型分类系统,以便更好地认识、利用和管理各类景观,达到人地共生和持续发展的目的。2　沙湾县环境概况沙湾县地处北疆天山中部的依连哈比尔尕山北麓与准噶尔盆地南缘之间,界于Ｅ84°57′～86°09′和Ｎ43°20′～…     

Cyclooxygenase-2, Not Microsomal Prostaglandin E Synthase-1, Is the Mechanism for Interleukin-1β-induced Prostaglandin E2 Production and Inhibition of Insulin Secretion in Pancreatic Islets

Arachidonic acid is converted to prostaglandin E(2) (PGE(2)) by a sequential enzymatic reaction performed by two isoenzyme groups, cyclooxygenases (COX-1 and COX-2) and terminal prostaglandin E synthases (cPGES, mPGES-1, and mPGES-2). mPGES-1 is widely considered to be the final enzyme regulating COX-2-dependent PGE(2) synthesis. These generalizations have been based in most part on experiments utilizing gene expression analyses of cell lines and tumor tissue. To assess the relevance of these generalizations to a native mammalian tissue, we used isolated human and rodent pancreatic islets to examine interleukin (IL)-1β-induced PGE(2) production, because PGE(2) has been shown to mediate IL-1β inhibition of islet function. Rat islets constitutively expressed mRNAs of COX-1, COX-2, cPGES, and mPGES-1. As expected, IL-1β increased mRNA levels for COX-2 and mPGES-1, but not for COX-1 or cPGES. Basal protein levels of COX-1, cPGES, and mPGES-2 were readily detected in whole cell extracts but were not regulated by IL-1β. IL-1β increased protein levels of COX-2, but unexpectedly mPGES-1 protein levels were low and unaffected. In microsomal extracts, mPGES-1 protein was barely detectable in rat islets but clearly present in human islets; however, in neither case did IL-1β increase mPGES-1 protein levels. To further assess the importance of mPGES-1 to IL-1β regulation of an islet physiologic response, glucose-stimulated insulin secretion was examined in isolated islets of WT and mPGES-1-deficient mice. IL-1β inhibited glucose-stimulated insulin secretion equally in both WT and mPGES-1(-/-) islets, indicating that COX-2, not mPGES-1, mediates IL-1β-induced PGE(2) production and subsequent inhibition of insulin secretion.     

Overexpression of a sterol C-24(28) reductase increases ergosterol production in Saccharomyces cerevisiae

Three plasmids, pHX4, pHXA4 and pHXC4, containing sterol C-24(28) reductase gene (ERG4) under the control of ERG4, ADH1 or CUP1 promoters, respectively, and the copper resistance gene as the selection marker were constructed, and they were then introduced into Saccharomyces cerevisiae. Ergosterol production in recombinant strains was enhanced. Under the optimal culture condition, ergosterol content in recombinant strains YEH56(pHX4), YEH56(pHXA4) and YEH56(pHXC4) was 1.2, 1.4 and 1.5-fold (47 mg g^–1) of that in the original strain.     

Disruption of sabR affects nikkomycin biosynthesis and morphogenesis in Streptomyces ansochromogenes

The gene, sabR, encoding a receptor for -butyrolactone, was cloned from the genomic DNA of Streptomyces ansochromogenes 7100. Its deduced protein shows strong homology to several -butyrolactone-binding proteins in Streptomyces. Disruption of sabR retarded nikkomycin production in liquid media containing glucose or glycerol as carbon source. Sporulation of sabR disruption mutants was earlier than the parent strain on solid media with glucose or glycerol as carbon source. However, disruption of sabR had no effect on either nikkomycin production or sporulation on media containing mannitol as carbon source, suggesting that sabR is a pleiotropic regulatory gene that controls the onset of nikkomycin production and sporulation in S. ansochromogenes and is related to the utilization of carbon source.