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Estimation of Cellobiohydrolase I Activity by Numerical Differentiation of Dynamic Ultraviolet Spectroscopy 总被引:1,自引:0,他引:1
Bin WU Yue ZHAO Pei-Ji GAO The State Key Laboratory of Microbial Technology Shandong University Jinan China 《Acta biochimica et biophysica Sinica》2006,(6)
1,4-β-D-glucan cellobiohydrolase I (CBH I),p-nitrophenyl β-D-cellobioside,p-nitrophenol andcellobiose show distinct ultraviolet spectra,allowing the design of an assay to track the dynamic process ofp-nitrophenyl β-D-cellobioside hydrolysis by CBH I.Based on the linear relationship between p-nitrophenolformation in the hydrolysate and its first derivative absorption Curve of AUC340_400_(nm)(area under the curve),a new sensitive assay for the determination of CBH I activity was developed.The dynamic parameters ofcatalysis reaction,such as Vm and k_(cat),can all be derived from this result.The influence of β-glucosidase andendoglucanase in crude enzyme sample on the assay was discussed in detail.This approach is useful foraccurate determination of the activity of CBHs. 相似文献
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Krapels IP Zielhuis GA Vroom F de Jong-van den Berg LT Kuijpers-Jagtman AM van der Molen AB Steegers-Theunissen RP;Eurocran Gene-Environment Interaction Group 《Birth defects research. Part A, Clinical and molecular teratology》2006,76(8):613-620
BACKGROUND: Nonsyndromic cleft lip with or without cleft palate (CL/P) or cleft palate only (CPO) are orofacial clefts and have a multifactorial etiology. The identification of amendable parental risk factors may contribute to a reduced occurrence of these malformations in the future. METHODS: Standardized demographic and periconceptional exposure data from 284 parents of a child with CL/P, 66 parents of a child with a CPO and 222 parents of a child without congenital malformations were collected at approximately 24 months after the periconceptional period of the index child. Univariate and multivariate logistic regression analyses were used to estimate relative risks by odds ratios (ORs) and 95% confidence intervals (95% CIs). RESULTS: Univariate results suggest that low parental education, periconceptional maternal medication use and illnesses, paternal smoking, and first-trimester maternal common cold increased CL/P risk. Pregnancy planning and periconceptional folic acid supplementation, however, reduced CL/P risk by approximately 50% (OR, 0.5; 95% CI, 0.3-0.8) and 40% (OR, 0.6; 95% CI, 0.4-0.9), respectively. Mostly comparable results were obtained for CPO. Being a boy (OR, 2.0; 95% CI, 1.4-3.0), folic acid supplementation (OR, 0.6; 95% CI, 0.4-0.9), and low paternal education (OR, 1.6; 95% CI, 1.0-2.3) mainly determined CL/P in the multivariate analyses, compared to low paternal (OR, 4.5; 95% CI, 2.1-9.4) and maternal medication use (OR, 2.0; 95% CI, 1.0-4.0) for CPO. CONCLUSIONS: Preconceptional counseling for orofacial cleft risk assessment should pay attention to maternal medication use, periconceptional folic acid supplementation, and exposures of the father. These determinants can be amended, thereby modifying orofacial cleft risk. 相似文献
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重金属在食用菌中的富集及对其生长代谢的影响 总被引:3,自引:0,他引:3
本文报导食用菌对重金属的吸收积累性能及重金属对食用菌生长代谢的影响。从供试的香菇、凤尾菇、金针菇及木耳等食用菌研究表明:对Hg、Pb、As、Ni、Cd、Cu、Zn等重金属均有不同程度的富集作用,其中对Hg的富集是极显著的,但对Pb则不明显。从福建省食用菌生产点采样测定结果看,子实体中的重金属含量均不超标。上述重金属对食用菌生长均有不同程度的不良影响,尤其以Hg和As为突出。对产量影响的顺序以香菇最大、凤尾菇次之、金针菇较弱。重金属在一定范围内对香菇抗坏血酸氧化酶活性有激活作用,对纤维素酶有抑制作用。 相似文献
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Novel Cellulase Profile of Trichoderma reesei Strains Constructed by cbh1 Gene Replacement with eg3 Gene Expression Cassette 总被引:3,自引:0,他引:3
Tian-Hong WANG* Ti LIU Zhi-Hong WU Shi-Li LIU Yi LU and Yin-Bo QU The State Key Laboratory of Microbial Technology Shandong University Jinan China 《Acta biochimica et biophysica Sinica》2004,(10)
The filamentous fungus Trichoderma reesei is consi-dered to be the most efficient cellulase producer, and hasa long history in the production of hydrolytic enzymes,which was widely used in the food and feed industriesand recently also used in the textile,… 相似文献
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将来源于水母的绿色荧光蛋白基因 (gfp)和来源于E .coli转座子Tn10的四环素阻遏蛋白基因 (tetR)共同构建到E .coli表达载体pET_30a +上 ,获得TetRC_端与GFPN_端融合蛋白。对经诱导表达并纯化后的融合蛋白 (TR∷GFP)进行荧光发射光谱分析表明 ,该融合蛋白保留了GFP的荧光特性 ,即在 395nm激发下 ,可在 5 10nm附近有特征发射峰。在加入四环素后 ,融合蛋白在 395nm激发下 ,在400nm~700nm范围内的发射光谱发生明显变化 ,荧光强度普遍增加 ,且以 510nm处最大发射峰增幅最大 ,由原来 1132增至 2214 ,而四环素对相同浓度的GFP与TetR荧光影响不大 ,结果表明该融合蛋白 ,能感受外界四环素 ,并产生一定的荧光变化。 相似文献
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拟诺卡菌属(Nocardiopsis)是拟诺卡菌科(Nocardiopsaceae) 的唯一属.该属内进行物种鉴别时通常是在多相分类方法基础上,以全基 因组杂交同源性在70%以下的为不同物种,此为国际公认的定种标准;但在 进行大量菌株的比对时操作比较复杂,于是多种基于DNA的基因图谱技术发 展起来.本实验利用适宜引物,对拟诺卡菌属15株基准株基因组DNA的16S -23S rDNA 间隔区序列(ITS)和REP序列进行了扩增,获得了两种基因指 纹图谱,同时根据UPGMA聚类法构建了相应的进化距离树图.结果表明,对 于拟诺卡菌属中不同物种的区分,两种基因图谱技术的分辨力相当,均可 以较好的呈现物种间差异,可以作为拟诺卡菌属菌株多相分类的组成部分 ,应用于物种水平的分类与鉴定. 相似文献
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NF-κB与肿瘤发生及药物筛选 总被引:2,自引:0,他引:2
NF-κB是一类能特异性地识别结合DNA的Rel类蛋白质二聚体转录因子。在静息细胞中 ,NF-κB与抑制性蛋白IκBs结合形成复合物 ,并被滞留于细胞质中而处于非活化状态 ;当细胞受到各种胞内外刺激时 ,IκBs被迅速地降解 ,NF-κB得以释放并进入细胞核 ,从而发挥其转录调节功能。NF-κB通过调控众多靶基因的转录表达而在免疫、炎症反应、细胞增殖与凋亡及肿瘤发生等许多生理学过程中发挥重要作用。介绍了NF-κB活化的调控机制 ,并对NF-κB信号通路在肿瘤发生等相关过程及其在药物筛选中的作用进行了探讨。 相似文献
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粉拟青霉种内nrDNA ITS分析 总被引:6,自引:0,他引:6
通过对20株粉拟青霉(Paecilomyces farinosus)ITS1-5.8S-ITS2(rDNA)区域序列测定,确定了粉拟青霉ITS序列,而韩国学者测定的粉拟青霉ITS序列应为细脚拟青霉(P.tenuipes)的序列。序列比较发现,韩国2株未定名的拟青霉(Paecilomyces spp.)菌株(KACC40219、KACC40221)应为粉拟青霉。基于本研究构建的邻接树推断,粉拟青霉的有性型可能是一种虫草。粉拟青霉的起源应为单源的。不同的粉拟青霉菌株的ITS序列具有多态性,源于同一地区的菌株的ITS变异也较大。ITS序列的证据表明,粉拟青霉菌株间的差异与地理来源及寄主均无相关性。 相似文献