首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   27篇
  免费   1篇
  国内免费   1篇
  2022年   1篇
  2019年   1篇
  2016年   1篇
  2015年   1篇
  2014年   2篇
  2011年   2篇
  2009年   1篇
  2008年   3篇
  2006年   3篇
  2005年   1篇
  2004年   2篇
  2003年   2篇
  1999年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1992年   1篇
  1987年   1篇
  1960年   1篇
  1956年   1篇
排序方式: 共有29条查询结果,搜索用时 46 毫秒
11.
Eight pairs of polymerase chain reaction (PCR) primers that amplify polymorphic microsatellite loci were developed for the African armyworm, Spodoptera exempta (Walker) to be used in the study of its population dynamics in sub‐Sahara Africa where the species is a major pest of cereals and rangeland. A magnetic beads based enrichment protocol was used; it appears that previously reported scarcity of microsatellites in Lepidoptera species does not apply to the African armyworm. All the loci showed significant heterozygote deficit; possibly because the samples were laboratory reared from limited stock. Four primer pairs successfully amplified single fragments of beet and fall armyworm DNA of comparable size to the African armyworm alleles.  相似文献   
12.
A simple and rapid enzyme-linked immunosorbent assay (ELISA)-type assay has been developed to screen hybridoma supernatant fluids with whole viable or killed bacteria as the antigen. The optimum concentration of acetone-killed and dried cell antigen for coating was 25–100 μg/ml. Screening of hybridoma supernatant fluids against whole cells, both with and without fixation, was assessed and both were equally sensitive. The data indicate that bacteria] fixation is detrimental in ELISA probably because of loss of antigenic structure. A highly specific monoclonal antibody (laM3) was produced against Shigella flexneri la and was employed to optimize the assay procedure.  相似文献   
13.
Mangrove tree species form ecologically and economically important forests along the tropical and subtropical coastlines of the world. Although low intrapopulation genetic diversity and high interpopulation genetic differentiation have been detected in most mangrove tree species, no direct investigation of pollen and propagule dispersal through paternity and/or parentage analysis and spatial genetic structure within populations has been conducted. We surveyed the mating system, pollen and propagule dispersal, and spatial genetic structure in a natural population of Kandelia candel, one of the typical viviparous mangrove tree species, using nuclear and chloroplast microsatellite markers. High diversity and outcrossing rates were observed. Paternity and parentage analysis and modelling estimations revealed the presence of an extremely short-distance component of pollen and propagule dispersal (pollen: 15.2 ± 14.9 m (SD) by paternity analysis and 34.4 m by modelling; propagule: 9.4 ± 13.8 m (SD) by parentage analysis, and 18.6 m by modelling). Genetic structure was significant at short distances, and a clumped distribution of chloroplast microsatellite genotypes was seen in K. candel adults. We conclude that the K. candel population was initiated by limited propagule founders from outside by long-distance dispersal followed by limited propagule dispersal from the founders, resulting in a half-sib family structure.  相似文献   
14.
Distribution of brackish-water zooplankton was surveyed in the Chikugo River estuary, Japan, at 3-h intervals for 24h, including several hours when the river was heavily flooded because of rainfall and discharge from an upstream dam. The populations of the dominant copepods Pseudodiaptomus inopinus and Sinocalanus sinensis were concentrated in the mixing zone of the salt wedge before river flooding. During the period of flooding, they were almost completely swept out from the river, but examination of water trapped by a sediment grab sampler revealed that adults of Pseudodiaptomus inopinus were aggregated immediately above the bottom of the submerged channel outside the river mouth. After the flood, aggregations of both species appeared again in the river together with the salt wedge, and the proportion of adults in the aggregations became significantly higher than before. These results suggest that immature copepods suffer population losses through river flooding, but that the copepods can survive such flooding by means of both behavioral and reproductive mechanisms; that is, adult copepods maintain their position on the bottom of submerged channels outside the river mouth during a river flood and replace the population loss through reproduction after the flood. Channels outside river mouths are thus regarded as important topographic refuges for river-estuarine zooplankton to survive a flood.  相似文献   
15.
16.
Pyrethroid-sprayed tents for malaria control   总被引:4,自引:0,他引:4  
Field trials were undertaken in the North West Frontier Province of Pakistan to determine the effects of pyrethroid-sprayed tents on feeding success, mortality and biting-rates of wild mosquitoes attracted to bait cows confined within the tents. Under natural conditions, endophagic mosquitoes rested only briefly in untreated tents during the night, followed by complete exodus at dawn. In tents sprayed on the interior surface with permethrin 0.5 mg/m2 or with deltamethrin 0.03 g/m2 the biting rate of Anopheles stephensi was reduced by about 40%; detergency against culicines and other anophelines was much less. Mortality-rates of bloodfed mosquitoes from the treated tents were 75%An.stephensi, 65%An. subpictus but only 10% of culicines. Outer fly-sheets prolonged the effective life of the treatment; bioassays on the sprayed inner-sheets showed that insecticidal efficacy remained high for over a year, whereas on tents without fly-sheets permethrin residual efficacy declined rapidly 20–40 weeks post-treatment. It is concluded that tent-spraying with fast-acting photostable residual pyrethroid insecticide would probably provide effective protection against malaria transmission for the inhabitants of tents in any part of the world where the vector mosquitoes are endophilic and susceptible to pyrethroids.  相似文献   
17.
18.
Bruguiera gymnorrhiza is an ecologically and somewhat economically important mangrove tree species. We isolated 10 polymorphic microsatellite loci from B. gymnorrhiza using a dual‐suppression polymerase chain reaction (PCR) technique. These loci provided microsatellite markers with polymorphism of two to five alleles per locus within 216 individuals from nine natural populations of B. gymnorrhiza on Iriomote Island, the Sakishima Islands, Japan. The expected and observed heterozygosities ranged from 0.220 to 0.720 and from 0.104 to 0.447, respectively.  相似文献   
19.
20.
Secondary metabolism plant glycosyltransferases (UGTs) ensure conjugation of sugar moieties to secondary metabolites (SMs) and glycosylation contributes to the great diversity, reactivity and regulation of SMs. UGT73B3 and UGT73B5, two UGTs of Arabidopsis thaliana (Arabidopsis), are involved in the hypersensitive response (HR) to the avirulent bacteria Pseudomonas syringae pv. tomato (Pst‐AvrRpm1), but their function in planta is unknown. Here, we report that ugt73b3, ugt73b5 and ugt73b3 ugt73b5 T‐DNA insertion mutants exhibited an accumulation of reactive oxygen species (ROS), an enhanced cell death during the HR to Pst‐AvrRpm1, whereas glutathione levels increased in the single mutants. In silico analyses indicate that UGT73B3 and UGT73B5 belong to the early salicylic acid (SA)induced genes whose pathogen‐induced expression is co‐regulated with genes related to cellular redox homeostasis and general detoxification. Analyses of metabolic alterations in ugt mutants reveal modification of SA and scopoletin contents which correlate with redox perturbation, and indicate quantitative modifications in the pattern of tryptophan‐derived SM accumulation after Pst‐AvrRpm1 inoculation. Our data suggest that UGT73B3 and UGT73B5 participate in regulation of redox status and general detoxification of ROS‐reactive SMs during the HR to Pst‐AvrRpm1, and that decreased resistance to Pst‐AvrRpm1 in ugt mutants is tightly linked to redox perturbation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号