PCR primers for polymorphic microsatellite loci in the desert locust,Schistocerca gregaria (Orthoptera: Acrididae)

Nine pairs of polymerase chain reaction (PCR) primers that amplify polymorphic microsatellite loci in the desert locust, Schistocerca gregaria (Forskal), were developed using a magnetic bead‐based enrichment protocol. A sample of 48 locusts collected during the 1993 and 1995 upsurge periods in Eritrea, East Africa, were genotyped. The number of alleles per locus ranged from six to 20; the average was 12.67. Allelic distributions were significantly different between samples from different localities.     

Isolation and characterization of eight compound microsatellite markers in a mangrove tree Kandelia candel (L.) Druce

Kandelia candel is an important mangrove tree species of family Rhizophoraceae. Here we isolated eight codominant compound microsatellite simple sequence repeat (SSR) loci from K. candel. Our isolated loci provided compound SSR markers with polymorphism of three to 11 alleles per locus. The expected and observed heterozygosities ranged from 0.230 to 0.887 and from 0.083 to 1.00, respectively. These markers would be the useful tools for analysing questions concerning population genetic structure and mating system of K. candel.     

小麦-大麦2H异代换系的鉴定

通过基因组原位杂交、重双端体测交及RFLP分析,解析了来自小麦品种"中国春"(Triticum aestivumL.cv."Chinese Spring"(CS))×大麦品种"Betzes"(Hordeum vulgare L.cv."Betzes")杂种后代15份材料的遗传组成,鉴定出6个二体异代换系;对与"中国春"重双端体DDT2A、DDT2B及DDT2D测交的F1代花粉母细胞减数分裂中期染色体构型进行观察,同时以小麦第二部分同源群短臂探针psr131进行RFLP分析,鉴定出一套遗传稳定的小麦-大麦2H二体异代换系2H(A)、2H(B)和2H(D).小麦第二部分同源群短臂探针psr131可作为追踪大麦2H染色体的RFLP标记.从代换系的生长势及其他农艺性状看,大麦2H染色体对小麦染色体2B和2D的补偿作用较好.通过考种观察到携带大麦α淀粉酶抑制蛋白基因的2H染色体导入小麦后,淀粉品质发生了改变,外观品质由原来"中国春"的半粉质转变为代换系的半角质.     

桉树精油及其活性物质对干鱼害虫白腹皮蠹的熏蒸毒性

为了评估桉树精油和α-蒎烯对白腹皮蠹Dermestes maculatus Degeer的杀虫作用,采用生测方法测定了不同剂量和不同处理时间下,其幼虫和成虫的死亡率。结果表明:用桉树精油及其活性成分α-蒎烯处理白腹皮蠹成虫和幼虫后,可显著影响其死亡率（P＜0.001）。白腹皮蠹的反应因化学物种类、剂量和暴露时间不同而异。当剂量为32 μL/cm³的桉树精油处理白腹皮蠹幼虫72 h后,死亡率可超过90%。同样的剂量对其成虫熏蒸72 h后也表现高毒。在相同的剂量和相同的暴露时间下,α-蒎烯对白腹皮蠹的成虫和幼虫也表现高毒,且成虫的抗性比幼虫强。Probit检验结果表明桉树精油比α-蒎烯更有效。以上结果说明这些天然产物对白腹皮蠹种群的控制是很有用的。     

The yins and yangs of ceramide

Since their discovery over 100 years ago,sphingolipids have caught the eyes and the imagination of scientists.Modern science has made many new insights on the cell biology and day-to-day functions of many integral sphingolipids,especially those of ceramids.Ceramide is recognized as a vital second messenger in the signal transduction process mediated by receptors of many cytokines and growth factors.A great part of our current understanding of ceramide has been achieved from apoptosis-related studies,however recent data in the fields of immunology,endocrinology and neurobiology,also suggest a fundamental involvement of ceramide in the onset of diseases.Therefore,understanding the diology of ceramide could be a key to unraveling many biological mechanisms and provide information for the treatment of some common diseases.     

DEVELOPMENT AND EVALUATION OF A RAPID ENZYME-LINKED IMMUNOFILTRATION ASSAY (ELIFA) AND AN ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) FOR THE DETECTION OF STAPHYLOCOCCAL ENTEROTOXIN B

An enzyme-linked immunofiltration assay (ELIFA) and a microtitre plate enzyme-linked immunosorbent assay (ELISA) were developed and compared for their ability to detect staphylococcal enterotoxin B (SEB). The double antibody capture format was used for both assays. Factors which improved the sensitivity of the ELIFA system were (1) addition of casein and thimerosal to the antigen dilution buffer; (2) addition of polyethylene glycol (MW 6000) to the detection and conjugate antibody dilution buffers; and (3) washing with diethanolamine buffer prior to addition of the substrate/chromogen. The ELIFA system had a turnaround time of approximately 1 h and a detection limit of 1 ng/mL of purified SEB. The ELISA had a total turnaround time of 21 h, or 3 h using plates pre-coated overnight with the capture antibody. The detection limit of the ELISA for purified SEB was 0.05 ng/mL. The detection limit of SEB in cheese samples spiked with purified enterotoxin and subjected to a simple extraction procedure was 1 ng/mL and 0.1 ng/mL of extract, with the ELIFA and the ELISA, respectively.     

PECTIC ENZYMES SECRETED BY VERTICILLIUM DAHLIAE AND THEIR ROLE IN THE DEVELOPMENT OF THE WILT DISEASE OF COTTON

An isolate of Verticillium dahliae obtained from Uganda was highly virulent to young cotton plants under greenhouse conditions. A hyaline variant which often appeared in culture was as virulent as the parent isolate, but preliminary experiments indicated that it did not survive as long in unsterile soil. The parent isolate grew rapidly in cotton plants after root inoculation and was isolated from stems and leaves well before the appearance of disease symptoms visible to the naked eye.
Protopectinase was produced in the absence of pectic materials, but more active preparations were obtained when media contained pectic substances. In general, there was a close correspondence between the protopectinase activity of culture filtrates and the toxicity of these filtrates to parenchymatous cells. Some separation of the two activities was obtained by heating enzyme solutions or by plasmolysing the test tissue.
Protopectinase solutions had little pectinesterase activity but rapidly reduced the viscosity of solutions of pectic substances. In general, the properties of protopectinase and the viscosity-reducing enzyme were similar.
Young cotton shoots wilted rapidly when placed in cell-free filtrates from cultures of the pathogen. Wilting was delayed under conditions unfavourable for transpiration. Evidence was obtained which showed that wilting was caused by the uptake of thermostable compounds of high molecular weight which impeded the upward flow of the vascular sap. Pronounced vascular browning was obtained only when solutions containing protopectinase were used. Wilting and vascular browning were obtained with solutions having little pectinesterase activity; in contrast, a solution having high pectinesterase activity produced relatively little vascular browning.     

Assortative mating among Anastrepha fraterculus (Diptera: Tephritidae) hybrids as a possible route to radiation of the fraterculus cryptic species complex

Reproductive isolation among populations of Anastrepha fraterculus has been found acting at the pre‐ and post‐zygotic levels. Differences in timing of sexual activity and male sexual pheromone composition among populations could partially account for prezygotic isolation. Hybrid males were found to produce a novel pheromone, which is a mix of parental pheromones. In the present study, we found that the hybrid females showed a significant preference to mate with hybrid males than with parental males. Male location during pheromone emission is associated with its reproductive success and, thus, differences in the location of males during courtship could also play a role in isolation. We found evidence that reproductive isolation is also related to the location of males during courtship. Hybrid male behaviour regarding location during pheromone release was found to be influenced by the maternal lineage. If these populations hybridized in the field, the hybrid females would tend to mate with hybrid males probably leading to the formation of a new entity within the A. fraterculus complex. This simple and fast process could be one reason explaining the high number of taxonomic entities within this complex. Further studies on other members of the fraterculus species group may reveal whether this can be considered as an example of homoploid hybrid speciation. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 346–354.     

小麦叶绿素酶基因家族的鉴定及其叶绿素降解过程中的功能预测

叶绿素酶(CLH)是植物叶绿素降解过程中的关键酶,在植物生长发育过程中发挥着重要作用.为了解小麦CLH基因家族成员在叶绿素降解过程中的功能差异,本试验采用生物信息学分析方法和实时荧光定量PCR(qRT-PCR)技术对小麦CLH基因家族进行鉴定和初步功能分析,结果表明:小麦中共鉴定到13个CLH成员(TaCLH1～TaC...     

Molecular Mechanisms and Genetic Basis of Heavy Metal Tolerance/Hyperaccumulation in Plants

Phytoremediation has gained increased attention as a cost-effective method for the remediation of heavy metal-contaminated sites. Because some plants possess a range of potential mechanisms that may be involved in the detoxification of heavy metals, they manage to survive under metal stresses. High tolerance to heavy metal toxicity could rely either on reduced uptake or increased plant internal sequestration,which is manifested by an interaction between a genotype and its environment. The growing application of molecular genetic technologies has led to increased understanding of mechanisms of heavy metal tolerance/accumulation in plants and, subsequently, many transgenic plants with increased heavy metal resistance,as well as increased uptake of heavy metals, have been developed for the purpose of phytoremediation. In the present review, our major objective is to concisely evaluate the progress made so far in understanding the molecular/cellular mechanisms and genetic basis that control the uptake and detoxification of metals by plants.