西藏搭格架铯硅华区热泉高温菌株的分离及特征研究          下载免费PDF全文

孔凡晶  王海雷  郑绵平  郑小娟 《地质学报》2007,81(12):1750-1753

从西藏搭格架铯硅华矿床区热泉中分离培养高温菌T4-1,并进行了格兰氏染色、显微镜观察、室内温度实验、16SrRNA基因分析等。结果表明,T4-1为杆状菌,格兰氏染色阳性,其生长范围为45~80℃,最适生长温度70℃。16SrRNA基因分析结果表明,该菌株属于地芽孢杆菌属(Geobacillus),在发育树上,T4-1菌株与高温烷烃地芽孢杆菌(Geobacillus the rmoleovorans)非常近。本研究为进一步开展西藏高温微生物资源以及微生物参与成矿作用的研究提供了首例。  相似文献   

地理属性和图形属性耦合的信息编码模型   总被引：3，自引：0，他引：3  

焦健  曾琪明 《遥感学报》1998,2(4):310-315

对地理信息进行编码,是ＧＩＳ设计中最重要的技术步骤之一,它代表着现实世界与信息世界的界面。本文从地图的模型化和空间认知过程出发,提出地理实体编码模型与图形实体编码模型的概念,并着重分析了代表这两类不同编码方式的软件对制图功能的影响,并在此基础上提出了地理属性和地图图形属性耦合的信息编码概念模型。  相似文献   

耐旱藓类的抗旱生理及其机理研究   总被引：15，自引：8，他引：15  

吴玉环  程佳强  冯虎元  安黎哲  高谦  程国栋 《中国沙漠》2004,24(1):23-29

耐旱藓类广泛分布于干旱及半干旱地区。本文综述分析了苔藓植物的耐旱能力和适应耐旱的形态结构和生理特征，从细胞和分子水平，对苔藓植物的耐旱机理进行了综述，并展望了我国苔藓植物的耐旱生理生态学研究前景。  相似文献   

An application of artificial intelligence for rainfall-runoff modeling   总被引：5，自引：0，他引：5  

Ali Aytek  M. Asce  Murat Alp 《Journal of Earth System Science》2008,117(2):145-155

This study proposes an application of two techniques of artificial intelligence (AI) for rainfall-runoff modeling: the artificial neural networks (ANN) and the evolutionary computation (EC). Two different ANN techniques, the feed forward back propagation (FFBP) and generalized regression neural network (GRNN) methods are compared with one EC method, Gene Expression Programming (GEP) which is a new evolutionary algorithm that evolves computer programs. The daily hydrometeorological data of three rainfall stations and one streamflow station for Juniata River Basin in Pennsylvania state of USA are taken into consideration in the model development. Statistical parameters such as average, standard deviation, coefficient of variation, skewness, minimum and maximum values, as well as criteria such as mean square error (MSE) and determination coefficient (R ²) are used to measure the performance of the models. The results indicate that the proposed genetic programming (GP) formulation performs quite well compared to results obtained by ANNs and is quite practical for use. It is concluded from the results that GEP can be proposed as an alternative to ANN models.  相似文献   

中国明对虾caspase 基因的克隆与表达分析   总被引：2，自引：0，他引：2  

宋光年  金松君  张继泉  相建海 《海洋科学》2010,34(12):1-7

利用细胞凋亡来清除多细胞器官受损伤或有害的细胞,为动物发育过程中保持机体平衡起到关键作用。为了研究细胞凋亡在甲壳类动物应对病毒感染后所起到的作用,作者利用同源克隆技术获得了中国明对虾(Fenneropenaeus chinensis)caspase基因(FcCasp)的cDNA序列,并分析了该基因在对虾受到白斑综合症病毒(white spot syndrome virus,简称WSSV)刺激后的表达变化规律。结果表明,该基因的cDNA含有954个核苷酸,编码317个氨基酸,具有caspase家族典型的QACRG五肽蛋白酶活性位点(190-194氨基酸)。对注射了WSSV的中国明对虾FcCasp的表达进行分析,在5个时间点取其肝胰脏样本,经real-time PCR检测发现,WSSV刺激3 h后,对虾肝胰脏中FcCasp的表达呈现显著性上调,说明FcCasp的表达与WSSV感染密切相关,提示FcCasp基因与细胞凋亡相关。  相似文献   

实时荧光定量PCR检测鳜IgM mRNA标准品质粒的构建   总被引：1，自引：0，他引：1  

刘雨果  潘厚军  陈偿  巩华  石存斌  吴淑勤 《广东海洋大学学报》2008,28(6)

利用SYBR Green I荧光定量PCR技术,建立鳜IgM-DNA定量标准品的制备方法。从浸泡免疫后的鳜头肾中提取总RNA逆转录合成cDNA,对目的片段进行PCR扩增、电泳纯化、T-A克隆及测序鉴定。将所得预期质粒梯度稀释后构建标准曲线并进行融解曲线分析。结果表明,当标准品的浓度在3.29×102～3.29×108拷贝/μL时,模板浓度与循环阈值(Ct)间的线性关系良好,相关系数r2达到0.999;融解曲线分析显示具特异的单个峰,表明扩增产物特异性非常好。此法制备的重组质粒标准品可用于对鳜IgM基因的转录水平进行测定。  相似文献   

Molecular cloning and expression analysis of Crustin-like gene from Chinese shrimp Fenneropenaeus chinensis     

LIU Fengsong  LI Fuhu  XIANG Jianhai  DONG Bo  LIU Yichen  ZHANG Xiaojun  ZHANG Liusuo 《海洋学报(英文版)》2008,27(2):81-92

A new member of antimicrobial protein genes of the Crustin family was cloned from haemocytes of the Chinese shrimp Fennero- penaeus chinensis by 3 ′and 5′ RACE. The full-length cDNA of Crustin-like gene contains a 390 bp open reading frame, encoding 130 amino acids. The deduced peptide contains a putative signal peptide of 17 amino acids and mature peptide of 113 amino acids. The molecular mass of the deduced mature peptide is 12. 3 ku. It is highly cationic with a theoretical isoelectric point of 8.5. The deduced amino acids sequence of this Crustin showed high homology with those of Penaeus （ Litopenaeus ） setferus. Northern blotting showed that the cloned Crustin gene was mainly expressed in haemocytes, gill, intestine, and RNA in situ hybridization indicated that the Crustin gene was constitutively expressed exclusively in haemocytes of these tissues. Capillary elec- trophoresis RT-PCR analysis showed that Crustin was up-regulated dramatically from 12 to 48 h after a brief decrease of mRNA during first 6 h in response to microbe infection. The level of Crustin mRNA began to restore at 72 h post-challenge. This indicated that Crustin gene might play an important role when shrimps are infected by bacterial pathogen.  相似文献   

Characterization of defensin gene from abalone <Emphasis Type="Italic">Haliotis discus hannai</Emphasis> and its deduced protein     

洪旭光  孙修勤  郑明刚  曲凌云  昝金东  张进兴 《中国海洋湖沼学报》2008,26(4):375-379

Defensin is one of preserved ancient host defensive materials formed in biological evolution. As a regulator and effector molecule, it is very important in animals＇ acquired immune system. This paper reports the defensin gene from the mixed liver and kidney cDNA library of abalone Haliotis discus hannai Ino. Sequence analysis shows that the gene sequence of full-length cDNA encodes 42 mature peptides （including six Cys）, molecular weight of 4 323 Da, and pI of 8.02. Amino acid sequence homology analysis shows that the peptides are highly similar （70% in common） to other insects defensin. Because of a typical insect-defensin structural character of mature peptide in the secondary structure, the polypeptide named Haliotis discus defensin （hd-def）, a novel of antimicrobial peptides, belongs to insects defensin subfamily. The RT-PCR result of Haliotis discus defensin shows that the gene can be expressed only in the hepatopancreas by Gram-negative and positive bacteria stimulation, which is ascribed to inducible expression. Therefore, it is revealed that the Haliotis discus defensin gene expression was related to the antibacterial infection of Haliotis discus hannai Ino.  相似文献   

Evaluation of gene expression programming approaches for estimating daily evaporation through spatial and temporal data scanning   总被引：1，自引：0，他引：1       下载免费PDF全文

Jalal Shiri  Pau Marti  Vijay P. Singh 《水文研究》2014,28(3):1215-1225

Evaporation of water from free water surfaces or from land surfaces is one of the main components of the hydrological cycle, and its occurrence is governed by various meteorological and physical factors. There is a multitude of models developed for estimating daily evaporation values by using weather data. This paper evaluates a Gene Expression Programming (GEP) model for estimating evaporation through spatial and temporal data scanning techniques. It is by using ‘leave‐one‐out’ procedures, a complete scan of the possible train and test set configurations is carried out according to temporal and spatial criteria. Comparison of the GEP model with empirical‐physical models shows that daily evaporation values computed by the GEP model are more accurate. Further, local calibration of the GEP model may not be needed, if enough climatic data are available at other stations. The performance of the GEP model fluctuates throughout the period of study and between stations. A suitable assessment of the model should consider a complete temporal and/or spatial scan of the data set used. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Comparative molecular analysis of bacterial communities inhabiting pristine and polluted with polycyclic aromatic hydrocarbons Black Sea coastal sediments     

Nadezhda H. Todorova  Roumyana S. Mironova  Ventzislav K. Karamfilov 《Marine pollution bulletin》2014

Molecular analysis was applied to characterize bacterial community structure in sediment samples collected from pristine site and oil-polluted Black Sea harbor. Amplified Ribosomal DNA Restriction Analysis (ARDRA) revealed a high similarity in the restriction patterns of both samples thus not demonstrating the effect of the pollutant on the structure of the bacterial communities. Constructed 16S rRNA gene libraries gave more detailed assessment of members. Results showed that α- and γ-Proteobacteria were dominant in the oil polluted site, whereas the pristine site was characterized by prevalence of Actinobacteria. The biodegradative potential of the adapted bacterial community in the oil-polluted sediments was demonstrated by the presence of the aromatic ring hydroxylating dioxygenase genes.  相似文献