水分胁迫下臭柏（Sabina vulgaris Ant.）光合特性和色素组成的季节变化

在室内砾耕栽培条件下,通过培养液中加入PEG(Polyethylene glycol 分子量为6000)以调节溶液渗透势,设置对照、弱水分胁迫和强水分胁迫3种处理 (培养液渗透势分别为0.02,-0.1,-0.34 MPa), 从1997年开始对臭柏进行长期干旱胁迫模拟实验.2003年测定了臭柏叶片光合色素和光合特性的季节变化.结果表明:对照区气孔导度季节变化在5月和9月份形成了典型的双峰曲线.尽管对照区的气孔导度明显高于其他两个处理,但日光合量却低于弱水分胁迫区.3个处理Chl a/b的比值在11月至翌年3月的低温期内均升高,以强水分胁迫区的增幅最大,其它月份该比值在3个处理之间没有显著的差异.3个处理的叶绿素总量(Chl a+b)在生长季的5～9月份均有不同程度的上升,但其中以强水分胁迫区增幅最小.在11月至翌年3月的低温期,各处理均大幅提高叶黄素总量(V+A+Z)和热耗散色素比例(A+Z)/(V+A+Z) (V:紫黄质、A:单环氧玉米黄质、Z:玉米黄质);在5～7月份的生长高峰期,各处理则明显降低了叶黄素总量和热耗散色素比例.这种趋势在强水分胁迫区表现的更为显著.     

六种检测猪瘟病毒方法的比较

【目的】本研究旨在比较6种检测猪瘟病毒方法的优缺点。【方法】应用病毒分离、胶体金免疫层析试纸条、抗原捕捉ELISA、反转录-聚合酶链式反应(RT-PCR)、TaqMan荧光定量RT-PCR(RT-qPCR)和反转录-环介导等温扩增方法(RT-LAMP)等6种方法,分别对50份疑似猪瘟病料中的猪瘟病毒(Classical swine fevervirus,CSFV)进行检测。【结果】结果表明:RT-qPCR和RT-LAMP方法检出阳性样品数为13份,RT-PCR为11份,病毒分离为10份,抗原捕捉ELISA为9份,胶体金试纸条为8份;6种方法均检测为阳性8份,均为阴性37份。【结论】结果提示,在对猪瘟病毒进行检测时,RT-qPCR、RT-LAMP和RT-PCR由于其灵敏性高,可作为首选检测方法,但操作时需要避免假阳性的出现;病毒分离方法虽然操作繁琐,但结果准确,是确诊猪瘟必不可少的检测方法;抗原捕捉ELISA和胶体金试纸条检测时间较短,由于其敏感性较低所限,主要用于对畜群进行检测,不适合个体检测。     

CO2浓度升高对不同品种水稻镉吸收和根形态的影响

为了探讨CO2浓度升高下不同水稻品种荣优398 (RY)和粤杂889(YZ)吸收重金属Cd差异性的原因,利用水培试验研究了不同浓度Cd处理下两种水稻吸收Cd的差异及根形态的变化特征.结果表明:低Cd处理(5、10、20 μmol·L-1)显著增加水稻生物量;当Cd浓度高于50 μmol·L-1时,Cd胁迫效果开始显现,水稻生物量减少.CO2浓度升高显著增加了水稻的生物量,增加了YZ茎Cd含量而降低了RY茎Cd含量.在5～200 μmol·L-1的Cd浓度下,CO2浓度升高增加了YZ活性根在总根长中的比例,降低了RY活性根的比例.CO2浓度升高下不同水稻品种根形态的变化是导致其对Cd吸收差异性的原因之一.     

PSMD: An extensive database for pan‐species microsatellite investigation and marker development

Microsatellites are widely distributed throughout nearly all genomes which have been extensively exploited as powerful genetic markers for diverse applications due to their high polymorphisms. Their length variations are involved in gene regulation and implicated in numerous genetic diseases even in cancers. Although much effort has been devoted in microsatellite database construction, the existing microsatellite databases still had some drawbacks, such as limited number of species, unfriendly export format, missing marker development, lack of compound microsatellites and absence of gene annotation, which seriously restricted researchers to perform downstream analysis. In order to overcome the above limitations, we developed PSMD (Pan‐Species Microsatellite Database, http://big.cdu.edu.cn/psmd/ ) as a web‐based database to facilitate researchers to easily identify microsatellites, exploit reliable molecular markers and compare microsatellite distribution pattern on genome‐wide scale. In current release, PSMD comprises 678,106,741 perfect microsatellites and 43,848,943 compound microsatellites from 18,408 organisms, which covered almost all species with available genomic data. In addition to interactive browse interface, PSMD also offers a flexible filter function for users to quickly gain desired microsatellites from large data sets. PSMD allows users to export GFF3 formatted file and CSV formatted statistical file for downstream analysis. We also implemented an online tool for analysing occurrence of microsatellites with user‐defined parameters. Furthermore, Primer3 was embedded to help users to design high‐quality primers with customizable settings. To our knowledge, PSMD is the most extensive resource which is likely to be adopted by scientists engaged in biological, medical, environmental and agricultural research.     

饲养方式对异色瓢虫幼虫生存的影响

在实验室条件下,用不同饲养器具和隔离物来饲养异色瓢虫并对其幼虫生长发育进行了比较。结果表明：低龄幼虫饲养器具以密闭型为好,可减少水分的蒸发;高龄幼虫的饲养器具以透气型为好,有利于幼虫后期的生长发育。饲养密度以每盒（16cm×12cm×6cm）30头为宜。饲养阻隔物以纸扇为佳,可促进高龄幼虫化蛹,缩短幼虫的发育历期。     

Overexpression of phosphoenolpyruvate carboxylase from Jatropha curcas increases fatty acid accumulation in Nicotiana tabacum

Jatropha curcas L. is an excellent biofuel crop, which displays a high efficiency of carbon absorption, and seed oil of Jatropha can be efficiently processed to produce high-quality biodiesel. Plant phosphoenolpyruvate carboxylases (PEPCs) play important roles not only in initial fixation of atmospheric CO₂ in C₄ and Crassulacean acid metabolism (CAM) plants, but also in fatty acid biosynthesis in seeds of oil plants by regulating carbon partitioning. Here, we identified JcPEPC1 from J. curcas L. by homology cloning, and alignment analysis of protein sequence revealed JcPEPC1 was a plant C₃-type PEPC, and shared high similarity to PEPC of castor oil plant Ricinus communis. We implemented detailed functional characterization of JcPEPC1 by expression analysis and transgenic tobacco. JcPEPC1 gene expressed in the leaves and seeds of J. curcas L., and remarkable increase of expression level was also detected at seed oil-accumulating stages. We overexpressed JcPEPC1 in tobacco, and showed the enzymatic activity of PEPC in transgenic plants was notably higher than wild type. Gas chromatography (GC) analysis elucidated the composition and total content of fatty acids were also altered. This study indicated JcPEPC1 played a fundamental role in fatty acid biosynthesis in Jatropha seeds. Our results proposed enhanced PEPC activity of Jatropha could improve biosynthesis of fatty acid, which implied critical functions in primary metabolism of non-photosynthetic PEPC.     

The pig genome project has plenty to squeal about

Significant progress on pig genetics and genomics research has been witnessed in recent years due to the integration of advanced molecular biology techniques, bioinformatics and computational biology, and the collaborative efforts of researchers in the swine genomics community. Progress on expanding the linkage map has slowed down, but the efforts have created a higher-resolution physical map integrating the clone map and BAC end sequence. The number of QTL mapped is still growing and most of the updated QTL mapping results are available through PigQTLdb. Additionally, expression studies using high-throughput microarrays and other gene expression techniques have made significant advancements. The number of identified non-coding RNAs is rapidly increasing and their exact regulatory functions are being explored. A publishable draft (build 10) of the swine genome sequence was available for the pig genomics community by the end of December 2010. Build 9 of the porcine genome is currently available with Ensembl annotation; manual annotation is ongoing. These drafts provide useful tools for such endeavors as comparative genomics and SNP scans for fine QTL mapping. A recent community-wide effort to create a 60K porcine SNP chip has greatly facilitated whole-genome association analyses, haplotype block construction and linkage disequilibrium mapping, which can contribute to whole-genome selection. The future 'systems biology' that integrates and optimizes the information from all research levels can enhance the pig community's understanding of the full complexity of the porcine genome. These recent technological advances and where they may lead are reviewed.