高稳定人胰岛素的晶体学研究:Ⅲ,A21-Asp突变体的结晶和初步晶体学分析

研究一系列有明确意义改性胰岛素的结构将有益于新型胰岛素分子的设计。经蛋白质工程制备的AspA21—人胰岛素(ADHI)基本保持了生物活力,而在酸性溶夜(pH3—4)中的稳定性比天然胰岛素在中性溶液中高5—10倍。本文报道ADHI的结晶、初步晶体学研究及中等分辨率衍射数据的收集。ADHI晶体属R3空间群:a_H=b_H=82.72埃,c_H=34.02埃。     

食品上的应用

923449重组体葡聚糖水解啤酒酵母菌株的构迷与分析〔英〕/Suihko,M.L.…了Appl.Mierobiol一B 1 oteehnol一1991,35(6)一751~757〔译自DBA,1992,11(5),92一02748〕 构建了4种不同类型的具纤维素酶活性底面发酵酿酒酵母(Saecha,o仍鲜ees ee:e‘s￡ae),方法为利用共转化和基因置换,使里氏木霉(T八-“hoder,a俨eese￡)vTT一D一50133的纤维素酶egll基因整合到酿酒酵母VTT一A一63015(A15)的PGKI或ADHI位点。用质粒pMA91和质粒pAAHS构建分别在PGKI和ADHI启动子和终止子之间携带egn基因的质粒pMN20和质粒pMN200。构建的单拷贝整合…     

耐多药鲍曼不动杆菌耐药基因检测结果的样本聚类分析

目的 调查一组耐药鲍曼不动杆菌菌株间的亲缘关系.方法 收集2010年1月至2010年12月浙江某医院ICU患者痰液标本中分离的耐药鲍曼不动杆菌共20株,采用聚合酶链反应(PCR)的方法分析3种与耐药相关的看家基因(carO、gyrA、parC)和55种水平转移获得与β-内酰胺类、氨基糖苷类、喹诺酮类耐药相关基因以及12种接合性质粒、转座子、插入序列、整合子等可移动遗传元件遗传标记,再对检测结果作样本聚类分析.结果 20株耐药鲍曼不动杆菌共检出3种与耐药相关的看家基因carO、gyrA、parC,4种获得性β-内酰胺类耐药基因(TEM-1、ADC-30、ADC-60、OXA-23),5种获得性氨基糖苷类耐药基因[aac(3)-Ⅰ、aac(6')-Ⅰ b、ant(3”)-Ⅰ、aph(3’)-Ⅰ、armA],2种抗菌制剂外排泵基因(adeB、qacE△1),5种可移动遗传元件的遗传标记(int Ⅰ 1、tnpU、tnp513、IS26、ISaba1).样本聚类分析提示,20株耐药鲍曼不动杆菌可分为A与B二个簇,A簇群均为多耐药(MDR)株;A簇群又可分为A1(ADC-60阳性)与A2簇群(ADC-30阳性),均为克隆传播.B簇群均为泛耐药(PDR)株,除8号株外为克隆传播.结论 MDR和PDR菌株中均存在克隆传播.获得菌株之间的亲缘关系对院内感染实时监测和控制院内感染意义重大.     

从耐药鲍曼不动杆菌中发现β-内酰胺酶ADC基因和膜孔蛋白carO基因新的变异型

目的 调查一组耐药鲍曼不动杆菌中β-内酰胺酶基因和膜孔蛋白基因的存在和变异情况.方法 收集2010年1月至2010年12月浙江某医院ICU患者痰液标本中分离的多耐药和泛耐药鲍曼不动杆菌各10株,用分子鉴定法鉴定菌种,再用聚合酶链反应(PCR)及序列分析的方法分析34种β-内酰胺酶基因与膜孔蛋白carO基因.结果 本组20株耐药鲍曼不动杆菌共检出TEM-1型20株(100％)、OXA-23型10株(50.0％)、ADC-30型12株(60.0％)、ADC基因新的变异型ADC-60型8株(40.0％)(GenBank登录号:JQ692087).10株PDR菌均检出OXA-23型β-内酰胺酶基因,而10株MDR菌则均未检出OXA-23型β-内酰胺酶基因.20株耐药鲍曼不动杆菌膜孔蛋白carO基因均存在有义突变,19株测得序列相同,翻译成氨基酸序列后与鲍曼不动杆菌敏感株(SDF)比较,一致率为76.0％.8号株carO基因序列与其他19株测得DNA序列不同,第351位缺失了12个碱基并导致过早出现终止密码子.结论 本组鲍曼不动杆菌对β-内酰胺类药物耐药主要与产TEM、ADC、OXA-23和carO基因存在有义突变相关.OXA-23型β-内酰胺酶基因阳性是PDR菌耐碳青霉烯类药物的原因.ADC基因存在新变异型:ADC-60是国内外首次报道.     

高稳定人胰岛素的晶体学研究:Ⅲ,A21-Asp突变体的结晶和初步晶体学分析

研究一系列有明确意义改性胰岛素的结构将有益于新型胰岛素分子的设计。经蛋白质工程制备的AspA21—人胰岛素(ADHI)基本保持了生物活力,而在酸性溶夜(pH3—4)中的稳定性比天然胰岛素在中性溶液中高5—10倍。本文报道ADHI的结晶、初步晶体学研究及中等分辨率衍射数据的收集。ADHI晶体属R3空间群:a_H=b_H=82.72埃,c_H=34.02埃。     

基因标记、转化、表达与检测

923585 连续培养酿酒酵母中热带假丝酵母细胞色素P45O alk基因表达的优化〔英刀Beretta,1.一了Ap- p 1 .Microbiol.Bioteehnol一1991,56(i) 一45一60〔译自DBA.2992,12(7),92一03614〕 在乙醇脱氢酶一I(ADHI)启动子U邑控下,在 His及Le。缺陷型酿酒酵母中表达了热带假丝酵母 细胞色素P450基因(P450a恢)。为长期稳定表 达,选用复制型质粒pDS509~6(由2一声m衍生而 来)及整合型质粒pIBI(二者均含有P450alk表达 盒)对酿酒酵母进行转化。在连续培养中,高稀释 率和高His浓度有利于质粒稳定性。不稳定很可能是因为pDS509一6与酵母染色体…     

中国北方汉族人群核呼吸因子-1基因+141G/T单核苷酸多态与冠心病发病的关联研究

目的:本研究旨在探讨IRF-1基因+141 G/T单核苷酸多态位点与中国北方汉族人群冠心病发病的相关关系。方法:本研究采用聚合酶链反应-限制性片段长度多态性对经过冠脉造影证实的冠状动脉有一条主要分支狭窄大于70%的675例冠心病患者和经过冠状动脉造影证实冠状动脉狭窄小于20%或完全正常的636例对照患者进行检验检,分析核呼吸因子IRF-1基因+141G/T单核苷酸多态位点的基因型和等位基因频率在两组间的分布情况。结果:核呼吸因子IRF-1基因+141 G/T单核苷酸多态位点三种基因型(GG型,GT型和TT型)在中国北方汉族人群冠心病组的分布频率分别为53.8%,36.2%和10.1%,在对照组的分布频率分别为45.6%,46.2%和8.2%,核呼吸因子IRF-1基因+141 G/T单核苷酸多态位点的基因型和等位基因频率分布在对照组和冠心病组之间存在统计学差异(P0.05)。Logistic回归分别校正冠心病的其他危险因素性别、年龄、体重指数、吸烟、高血压、高脂血症、糖尿病等后,核呼吸因子IRF-1基因+141 G/T单核苷酸多态位点与中国北方汉族人群的冠心病的发病存在相关关系(P0.05)。结论:核呼吸因子IRF-1基因+141 G/T单核苷酸多态与中国北方汉族人群冠心病的发病存在相关关系,IRF-1基因+141 G/T多态可能是中国北方汉族人群冠心病发病的独立危险因子。     

锌转运体Zip2对心肌缺血再灌注小鼠心肌线粒体呼吸的调控作用

本研究旨在探讨锌转运体Zip2 (SLC39A2)在心肌缺血再灌注(ischemia/reperfusion, I/R)过程中对线粒体呼吸的调控作用及其机制。通过冠状动脉左前降支结扎建立小鼠在体心肌I/R损伤模型,用电感耦合离子发射光谱仪(inductively coupled plasma-optical emission spectrometer, ICP-OES)测量心肌组织的锌含量,用高分辨呼吸测定系统(Oxygraph-2K)检测小鼠心肌线粒体呼吸功能和氧化磷酸化水平,采用Western blot技术检测小鼠心肌组织STAT3和ERK的磷酸化水平。结果显示:(1)与假手术组相比,野生型小鼠I/R心肌组织的锌含量明显降低,Zip2基因敲除小鼠I/R心肌组织的锌含量进一步降低;(2)与野生对照组相比,Zip2基因敲除组小鼠心肌线粒体呼吸控制率(respiratory control ratio, RCR)和氧化磷酸化水平降低,I/R后上述指标进一步降低;(3)与野生对照组相比,I/R后Zip2基因敲除组小鼠心肌组织STAT3 (Ser~(727))和ERK的蛋白磷酸化水平均明显降低;(4)与空载体感染组相比,I/R后STAT3感染组心肌线粒体呼吸功能明显提高,而STAT3负突变体感染组心肌线粒体呼吸功能则降低。STAT3过表达可逆转Zip2基因敲除对线粒体呼吸的抑制作用。以上结果提示,心肌I/R时Zip2通过STAT3来调控线粒体呼吸,其机制可能与STAT3 (Ser~(727))的磷酸化有关,这可能是Zip2保护心肌的分子机制之一。     

呼吸监护室下呼吸道铜绿假单胞菌β-内酰胺类抗生素耐药相关基因研究

目的了解呼吸监护室下呼吸道分离的铜绿假单胞菌中β-内酰胺类抗生素耐药相关基因存在状况。方法自呼吸监护室下呼吸道感染患者的痰标本中分离37株铜绿假单胞菌,采用聚合酶链反应(PCR)检测耐药基因(TEM、SHV、OXA-1群、OXA-10群、PER、VEB、GES、CARB、IMP、VIM、SPM、GIM、DHA和oprD2)。结果37株铜绿假单胞菌中CARB阳性15株(40.5%),oprD2基因缺失33株(89.2%),其余基因均阴性。结论呼吸监护室下呼吸道分离的铜绿假单胞菌CARB基因携带率高,oprD2基因缺失严重。     

OPRM1(A118G)基因多态性与肺癌癌痛患者镇痛效果的相关性

目的:探讨阿片样物质受体(μ1 opioid receptor,OPRM1)(A118G)基因多态性与肺癌癌痛患者镇痛效果的相关性。方法:选取本院2017年3月至2019年10月收治的360例肺癌患者作为研究对象,判断患者阿片耐受与不良反应发生情况。收集患者血液指标,检测OPRM1(A118G)基因多态性情况并进行相关性分析。结果:在360例患者中,阿片耐受78例(耐受组),耐受率为21.7%;耐受组的性别、年龄、体重指数、肿瘤最大直径等与非耐受组对比差异无统计学意义(P0.05),两组临床分期与淋巴结转移等对比差异有统计学意义(P0.05)。OPRM1(A118G)基因共有AA、AG、GG三种基因型,两组人群的OPRM1(A118G)基因型分布均符合Hardy-Weinberg平衡定律;两组OPRM1(A118G)基因型分布差异具有统计学意义,耐受组的OPRM1(A118G)基因GG基因型比例显著高于非耐受组(P0.05),等位基因G频率显著高于非耐受组(P0.05);耐受组的呼吸抑制、恶心呕吐、头晕、皮肤瘙痒等不良反应发生率为35.9%,显著高于非耐受组的2.8%(P0.05)。直线相关性分析显示OPRM1(A118G)基因GG基因型与阿片耐受、淋巴结转移、临床分期都呈现相关性(P0.05);二分类变量Logistic回归分析显示OPRM1(A118G)基因GG基因型、临床分期、淋巴结转移为影响阿片耐受的主要因素(P0.05)。结论:肺癌癌痛患者在镇痛中存在阿片耐受情况,与患者的OPRM1(A118G)基因多态性与治疗不良反应显著相关,OPRM1(A118G)基因GG基因型、临床分期、淋巴结转移为影响阿片耐受的主要因素。     

Conditional Overdominance at an Alcohol Dehydrogenase Locus in Yeast

Documented examples of heterosis attributable to overdominance at specific protein-encoding gene loci have rarely been reported, the association of sickle cell hemoglobin with malarial resistance being the best documented example of this phenomenon. Here we report an example of overdominance that is temperature- and allyl alcohol-dependent and due to heterozygosity at the ADH1 locus, involving two ADHI functional mutants. Overdominance appears to be due in part to an intermediate level of ADHI activity in the heterozygote. Unlike previous work with this this system using haploid strains, the NAD+/NADH ratios show no negative correlation with allyl alcohol resistance. This system is formally equivalent to that of sickle cell hemoglobin and shows promise as a tool for investigating the physiological basis for overdominance.     

Functional Alcohol Dehydrogenase Mutants of Saccharomyces cerevisiae Conferring Temperature-Conditional Allyl Alcohol Resistance

Selection for allyl alcohol resistance in respiratory incompetent yeast is a highly specific method for isolating functional mutations at ADH1, the gene coding for the cytoplasmic alcohol dehydrogenase, ADHI. Because of the nature of this selection scheme, the ADHI activity of such mutants is retained, but the kinetic characteristics of the enzymes are altered. The high specificity for targeting functional mutations at this locus suggested that selection for enzyme variants with more subtle phenotypic effects might be possible. Here, we describe functional ADHI mutants that are temperature-conditional in their allyl alcohol resistance. Haploid cells of one of these mutants grow well on plates at 10 mM allyl alcohol at 19 degrees, but not at 37 degrees, the restrictive temperature. A second mutant grows well at 10 mM at 37 degrees, but its growth is restricted at 19 degrees. What distinguishes these mutants from other temperature-sensitive mutants is that the temperature-conditional growth phenotypes described here must be due to interactions between allyl alcohol levels and ADHI functional properties and cannot be due to lability of the enzyme at the restrictive temperature. This system shows promise for the investigation of functional enzyme variants that differ by only one or two amino acid residues but have significant temperature- and substrate-conditional effects on growth phenotypes in both the haploids and the diploids.     

Purification of two alcohol dehydrogenases from Zymomonas mobilis and their properties

Summary Two alcohol dehydrogenases (ADHI and ADHII, EC 1.1.1.1) were purified to homogeneity from the cell extract of Zymomonas mobilis. The subunit molecular weights of ADHI and ADHII were 40,000 and 38,000, respectively, and both enzymes were homologous dimers. The optimal pHs of ADHI in ethanol oxidation and acetaldehyde reduction reactions were 9.5 and 4.5, and those of ADHII were 9.5 and 6.5, respectively. The optimal temperatures of ADHI and ADHII were 55° C and 45° C, respectively. ADHI was heat-inactivated at 65° C at a 10-fold higher rate than ADHII. ADHI and ADHII were inhibited by 4 M and 1 mM p-chloromercuribenzoate, respectively, and the inhibitions were reversed by the addition of 70 mM 2-mercaptoethanol. ADHII activity was enhanced by 0.02 to 2 mM CoCl₂ and inhibited by 0.4 mM o-phenanthroline; and the activity of inactivated ADHII was restored by addition of 1 mM CoCl₂ or ZnCl₂.ADHI was active on most primary alcohols but not secondary alcohols. ADHII was active on only ethanol, n-propanol, allylalcohol, and furfuryl alcohol.In the anaerobic culture of Z. mobilis, ADHII activity accounted for more than 80% of total alcohol dehydrogenase activity. In aerobic culture, ADHII was the main enzyme but was produced only in the early growth phase.     

Modulation of alcohol dehydrogenase isoenzyme levels in Zymomonas mobilis by iron and zinc.

Zymomonas mobilis is an unusual microorganism which utilizes both iron-containing alcohol dehydrogenase (ADHII) and zinc-containing alcohol dehydrogenase (ADHI) isoenzymes during fermentative growth. This organism is obligately ethanologenic, and alcohol dehydrogenase activity is essential. The activities of ADHI and ADHII were altered by supplementing growth medium with iron or zinc salts and by iron starvation. Growth under iron-limiting conditions (chelators, minimal medium) reduced ADHII activity but did not prevent the synthesis of the ADHII protein. The inactive form of this enzyme appeared quite stable, was not renatured by iron addition, and persisted in the cell. The iron-induced increase in ADHII activity required de novo synthesis which was blocked by antibiotic additions. The ability of Z. mobilis to synthesize ADHII and ADHI may be advantageous in nature.     

Oxidative phosphorylation in Escherichia coli. Characterization of mutant strains in which F1-ATPase contains abnormal beta-subunits.

To facilitate study of the role of the beta-subunit in the membrane-bound proton-translocating ATPase of Escherichia coli, we identified mutant strains from which an F1-ATPase containing abnormal beta-subunits can be purified. Seventeen strains of E. coli, characterized by genetic complementation tests as carrying mutations in the uncD gene (which codes for the beta-subunit), were studied. The majority of these strains (11) were judged to be not useful, as their membranes lacked ATPase activity, and were either proton-permeable as prepared or remained proton-impermeable after washing with buffer of low ionic strength. A further two strains were of a type not hitherto reported, in that their membranes had ATPase activity, were proton-impermeable as prepared, and were not rendered proton-permeable by washing in buffer of low ionic strength. Presumably in these two strains F1-ATPase is not released in soluble form by this procedure. F1-ATPase of normal molecular size were purified from strains AN1340 (uncD478), AN937 (uncD430), AN938 (uncD431) and AN1543 (uncD484). F1-ATPase from strain AN1340 (uncD478) had 15% of normal specific Mg-dependent ATPase activity and 22% of normal ATP-synthesis activity. The F1-ATPase preparations from strains AN937, AN938 and AN1543 had respectively 1.7%, 1.8% and 0.2% of normal specific Mg-dependent ATPase activity, and each of these preparations had very low ATP-synthesis activity. The yield of F1-ATPase from the four strains described was almost twice that obtained from a normal haploid strain. The kinetics of Ca-dependent ATPase activity were unusual in each of the four F1-ATPase preparations. It is likely that these four mutant uncD F1-ATPase preparations will prove valuable for further experimental study of the F1-ATPase catalytic mechanism.     

金针菇子实体颜色的遗传规律研究

以金针菇黄色菌株F19和白色菌株F8801为亲本,原生质体单核化获得两亲本的单核菌株,配对杂交获得F1,从F1的子实体分离单孢菌株,与两亲本的原生质体单核化菌株进行回交配对,出菇观察子实体颜色,分析菇体颜色的遗传规律。研究结果表明,黄色为显性、白色为隐性,菇体颜色受一对基因(Cc)控制,与不亲和性因子A或B都没有连锁。