寄生于大鳍鳠的鳠鱼鳋的生态研究

鱯鱼鳋能在16℃以上的适宜水温中繁殖,在25℃左右,繁殖快,感染力强;鱯鱼鳋的感染有明显的季节变化,这是由外界因素(如水温、水质和水体流速等)的变化以及它的繁殖和感染力的变化所引起的;鱯鱼鳋的频数在宿主种群中呈负二项分布;鱯鱼鳋的感染可能引起大鳍鱯产生抵抗力,抵抗力的强度随感染次数和感染强度增加而增强;在天然条件下,影响鱯鱼鳋种群消长的主要因素是非密度制约因素和大鳍鱯的免疫反应。     

尖吻蝮咬伤与心脏损害：附20例分析

本文报告尖吻蝮咬伤并心脏受累20例。经中西医结合治愈19例(95％),死亡1例(5％),并对其发病机理及治疗进行了讨论。     

脑红蛋白对活性氧的清除作用及其在神经系统疾病中的功能意义

脑红蛋白(NGB)是神经系统特异性携氧珠蛋白,可作为内源性神经保护因子保护神经元免受缺血/缺氧性损伤。活性氧(ROS)是机体正常代谢的中间产物,生理状态下体内ROS处于产生与清除的动态平衡中。机体内过多的ROS是产生氧化应激的重要因素,也是导致多种疾病包括神经系统疾病的重要原因,因此清除体内过多的ROS是防治神经系统疾病的重要措施。目前已发现NGB在清除过多ROS方面可能起重要作用,这对调节ROS的内稳态水平具有重要意义。本文就NGB对ROS的清除作用及其在神经系统疾病中的功能意义进行综述。     

产超广谱β-内酰胺酶细菌耐药性基因型分析

检测我院产超广谱β-内酰胺酶(ESBLs)大肠埃希菌和肺炎克雷伯菌的耐药性和基因型。表型确定临床分离产ESBLs的大肠埃希菌和肺炎克雷伯菌56株,应用PCR基因扩增技术及双脱氧DNA测序方法,分别对TEM、SHV、CTX-M-1、CTX-M-2和CTX-M-9编码基因进行分析。产酶菌株对亚胺培南、美洛培南、阿米卡星、头孢吡肟耐药性较低,对其他16种抗生素耐药性较高。在56株菌株中有50株为CTX-M型,占89%,34株为TEM型(60.7%),20株SHV型(35.7%);其中CTX-M-9型共计39株占78%,CTX-M-1型19株占38%,CTX-M-2型16株占32%。产ESBLs大肠埃希菌和肺炎克雷伯菌的耐药性值得关注,主要临床流行基因型是CTX-M型。     

一个新水稻温敏感叶色突变体的遗传分析及其基因分子定位

在粳稻品种嘉花1号(Oryza sativa L. ssp. japonica ‘Jiahua No.1’)种子经⁶⁰Co γ射线辐照处理的后代中, 发现了1个低温敏感叶色突变体mr21。在较低温度(<25.0°C)条件下, 该突变体幼苗叶色呈黄色; 随着温度逐渐升高, 叶色由黄转绿,其临界温度约为27.5°C; 在低温条件下, 突变体幼苗总叶绿素含量以及叶绿素a、b的含量均较野生型嘉花1号明显下降, 表明该突变体的叶色性状具有明显的温敏感性。遗传分析表明, 该突变体叶色性状受1对隐性核基因控制, 暂将该突变基因命名为thermo-sensitive leaf-color 1(tsl-1)。以该突变体与籼稻9311(Oryza sativa L. ssp. indica ‘9311’)杂交的F₂代分离群体作为定位群体, 利用SSR分子标记将tsl-1基因初步定位在水稻(Oryza sativa)第1号染色体短臂上的MM1799与RM8132分子标记之间, 其遗传距离分别为2.4 cM和3.0 cM; 然后, 进一步利用扩大F₂代群体及新发展的分子标记将tsl-1基因定位在分子标记InDel2与InDel4之间的198 kb内。研究结果为今后对该基因的克隆和功能分析奠定了基础。     

Assessing indica-japonica differentiation of improved rice varieties using microsatellite markers

To assess the indica-japonica differentiation of improved rice varieties, a total of 512 modem varieties including 301 indica and 211 japonica accessions were analyzed using 36 microsatellites. The Fst coefficients ranged from 0.002 to 0.730 among the loci with an average of 0.315. Significant differentiation was detected at 94.4% of the loci studied （P 〈 0.05, pairwise Fst tests）, indicating that there was a high level of indica-japonica differentiation within the improved varieties. At 18 loci, about 74%-98% of the alleles of indica and japonica accessions were distributed in two ranges of amplicon length. Linkage disequilibrium analysis showed that the distribution trends were significantly nonrandomly associated. Using the differentiation trends at the 18 loci, microsatellite index （MI） was proposed for discrimination of the two subspecies. When rice accessions with MI value greater than zero were classified as indica, and those with MI value smaller than zero were classified as japonica, about 96.1% of the accessions could be classified. This result agrees with the classification based on morphological-physiological characters, indicating that this method is feasible and effective.     

Identification and characterization of NARROW AND ROLLED LEAF 1, a novel gene regulating leaf morphology and plant architecture in rice

Leaf morphology is an important agronomic trait in rice breeding. We isolated three allelic mutants of NARROW AND ROLLED LEAF 1 (nrl1) which showed phenotypes of reduced leaf width and semi-rolled leaves and different degrees of dwarfism. Microscopic analysis indicated that the nrl1-1 mutant had fewer longitudinal veins and smaller adaxial bulliform cells compared with the wild-type. The NRL1 gene was mapped to the chromosome 12 and encodes the cellulose synthase-like protein D4 (OsCslD4). Sequence analyses revealed single base substitutions in the three allelic mutants. Genetic complementation and over-expression of the OsCslD4 gene confirmed the identity of NRL1. The gene was expressed in all tested organs of rice at the heading stage and expression level was higher in vigorously growing organs, such as roots, sheaths and panicles than in elsewhere. In the mutant leaves, however, the expression level was lower than that in the wild-type. We conclude that OsCslD4 encoded by NRL1 plays a critical role in leaf morphogenesis and vegetative development in rice.     

花椒属植物生物碱研究进展

花椒属植物全世界约有250种,我国约有39种14变种。近年来研究发现花椒属植物生物碱具有多种药理作用与临床功能,现就近20年来花椒属生物碱和花椒生物碱的提取、分离、测定方法以及其药理作用等研究作一综述。     

植物细胞多倍体诱导实验方法的改进

从植物多倍体诱导实验材料处理的方法上,介绍了改进植物多倍体诱导实验的技术,提高了多倍体细胞的分裂指数。实验用0．1％和0．01％浓度的秋水仙素溶液分别处理大蒜根尖24h、36h、48h、72h,进行多倍体诱导,再在清水中分别培养0h、12h、24h、36h,结果表明经清水培养的多倍体细胞分裂指数高于对照：0．01％浓度的秋水仙素处理的多倍体细胞分裂指数高于0．1％多倍体细胞分裂指数。