Identifying the predator complex of <Emphasis Type="Italic">Homalodisca vitripennis</Emphasis> (Hemiptera: Cicadellidae): a comparative study of the efficacy of an ELISA and PCR gut content assay

A growing number of ecologists are using molecular gut content assays to qualitatively measure predation. The two most popular gut content assays are immunoassays employing pest-specific monoclonal antibodies (mAb) and polymerase chain reaction (PCR) assays employing pest-specific DNA. Here, we present results from the first study to simultaneously use both methods to identify predators of the glassy winged sharpshooter (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae). A total of 1,229 arthropod predators, representing 30 taxa, were collected from urban landscapes in central California and assayed first by means of enzyme-linked immunosorbent assay (ELISA) using a GWSS egg-specific mAb and then by PCR using a GWSS-specific DNA marker that amplifies a 197-base pair fragment of its cytochrome oxidase gene (subunit I). The gut content analyses revealed that GWSS remains were present in 15.5% of the predators examined, with 18% of the spiders and 11% of the insect predators testing positive. Common spider predators included members of the Salticidae, Clubionidae, Anyphaenidae, Miturgidae, and Corinnidae families. Common insect predators included lacewings (Neuroptera: Chrysopidae), praying mantis (Mantodea: Mantidae), ants (Hymenoptera: Formicidae), assassin bugs (Hemiptera: Reduviidae), and damsel bugs (Hemiptera: Nabidae). Comparison of the two assays indicated that they were not equally effective at detecting GWSS remains in predator guts. The advantages of combining the attributes of both types of assays to more precisely assess field predation and the pros and cons of each assay for mass-screening predators are discussed.     

Root inoculation with a forest soil streptomycete leads to locally and systemically increased resistance against phytopathogens in Norway spruce

Soil streptomycetes are commonly antagonistic against plant pathogens. However, interactions involving increased defense responses in the host plant, leading to suppression of plant disease development, have not yet been detailed. Here, the mechanisms were studied of disease suppression by Streptomyces sp. GB 4-2 against Heterobasidion root and butt rot in Norway spruce (Picea abies) seedlings. GB 4-2 promoted mycelial growth of the phytopathogenic fungus, germination rate of fungal spores, extension of germ tubes and early colonization of outer cortical layers of the plant root. Reduced colonization of the inner cortical cell layers was accompanied by the induction of cell wall appositions, and increased xylem formation in the vascular cylinder emerged after bacterium-fungus coinoculation. Bacterial treatment led to decreased water content in roots and needles and increased photosynthetic yield (F(v)/F(m)) and peroxidase activities in needles. The infection of needles by Botrytis cinerea was reduced by bacterial pretreatment. Complex interactions of GB 4-2 with Norway spruce and Heterobasidion abietinum were discovered. The bacterium promoted the growth of the phytopathogenic fungus but induced plant defense responses. Host responses indicate that GB 4-2 induces both local and systemic defense responses in Norway spruce.     

Effect of dengue vector control interventions on entomological parameters in developing countries: a systematic review and meta-analysis

The aim of this review was to compare the effects of different dengue vector control interventions (i.e. biological control, chemical control, environmental management and integrated vector management) with respect to the following entomological parameters: Breteau index (BI), container index (CI), and house index (HI). We systematically searched PubMed, ISI Web of Science, Science Direct, the Dengue Bulletin of the World Health Organization and reference lists of retrieved articles on dengue vector control interventions in developing countries. We extracted data on the effectiveness of different dengue vector control interventions (defined as the relative reduction of an entomological measure caused by the intervention compared with the control or pre-intervention phase) and calculated a measure of combined relative effectiveness, with 95% confidence intervals (95% c.i.). We identified 56 publications covering 61 dengue vector control interventions. Integrated vector management was found to be the most effective method to reduce the CI, HI and BI, resulting in random combined relative effectiveness values of 0.12 (95% c.i. 0.02-0.62), 0.17 (95% c.i. 0.02-1.28) and 0.33 (95% c.i. 0.22-0.48), respectively. Environmental management showed a relatively low effectiveness of 0.71 (95% c.i. 0.55-0.90) for the BI, 0.49 (95% c.i. 0.30-0.79) for the CI and 0.43 (95% c.i. 0.31-0.59) for the HI. Biological control (relative effectiveness for the CI: 0.18) usually targeted a small number of people (median population size: 200; range 20-2500), whereas integrated vector management focused on larger populations (median: 12 450; range: 210-9 600 000). In conclusion, dengue vector control is effective in reducing vector populations, particularly when interventions use a community-based, integrated approach, which is tailored to local eco-epidemiological and sociocultural settings and combined with educational programmes to increase knowledge and understanding of best practice. New research should assess the density-dependent effectiveness of each control measure in order to estimate whether reducing vector numbers has an impact on dengue transmission when populations are at a critical threshold.     

加纳籽中5-羟基色氨酸的研究进展

5-羟基色氨酸主要存在于豆科植物中,尤其在加纳籽中含量居多。在体内,5-羟基色氨酸是5-羟色胺的前体,是一类重要的神经类药物。对5-羟基色氨酸的生物学作用、检测、生产方面的最新研究进行了概述,并对5-羟基色氨酸资源匮乏的问题提出了建议。     

苹果炭疽菌低毒性菌株生物学特性的研究

研究了温度、pH值及碳源对苹果炭疽病菌(Colletotrichum gloeosporioides)强毒性菌株及低毒性菌株的生长、产孢和孢子萌发的影响。结果表明:菌丝生长温度范围10℃~35℃、最适温度为28℃,低毒菌株生长速率较快,产生分生孢子的温度范围与分生孢子萌发的温度范围为15℃~35℃,低毒菌株孢子萌发率较高,菌丝生长的最适pH值基本相同,pH在3~10的范围内均能生长和产孢,产生分生孢子的最适pH值为4~5,但经离子注入的低毒性菌株C100-2-5的产孢量在不同的pH值和温度下却一直低于经磁场处理的C0.25-1-2和强毒性菌株(对照)。分生孢子的致死温度为47℃、15 min或50℃、5 min。但菌丝的致死温度却不同,对照为60℃、20 min,C0.25-1-2为60℃、25 min,C100-2-5为60℃、30 min,65℃下5 min(及5 min以上)。     

氮离子束注入姬松茸担孢子的生物学效应研究

氮离子束注入与紫外线辐射对姬松茸担孢子萌发的影响显著不同,表现出一定程度的马鞍型效应.不同剂量的氮离子束注入姬松茸担孢子,其产生的生物学效应不同:氮离子注入束流为200×2.6×1013N /cm2,筛选到一株箱栽生物学效率提高47.0%的姬松茸新菌株AbML11;氮离子注入束流为400×2.6×1013N /cm2,筛选到一株子实体呈现白色突变的姬松茸新菌株AbML7;氮离子注入束流为500×2.6×10"N13/cm2,筛选到一株具有AEC抗性突变的姬松茸新菌株AbML2.     

A型激酶锚定蛋白及其复合物结构与功能

A型激酶锚定蛋白(A-kinase anchoring proteins,AKAPs)是一类结构不同而功能相关的蛋白家族,其主要功能是将cAMP依赖性蛋白激酶A（PKA）锚定于特定的亚细胞结构.PKA是第二信使cAMP的主要效应器,而AKAPs在靶向定位和调节PKA介导的磷酸化事件方面扮演重要角色. AKAPs更为重要的功能是与多种信号分子形成信号复合物,从时间和空间上整合cAMP-PKA和其他信号途径.本文将对AKAPs及其信号复合物的结构特点和参与细胞信号转导的功能机制及其研究现状进行概述.     

2006年广州登革热病原体的分离鉴定及其生物学性质的观察

目的：对2006年广州流行登革热病原进行分离鉴定及生物学性质研究。方法：采用传代蚊细胞微量培养方法对2006年广州登革热病原进行分离,并通过脑内途径观察其对乳鼠的致病性;经间接免疫荧光和RT-PCR技术,对患者血清标本中的病毒特异抗体及新分离的病原体进行检测和鉴定;将此次分离的病原体与1980年分离的同型毒株进行生物学性质比较。结果：从57份患者血清标本中分离出10株病毒,在传代蚊细胞中可产生稳定的细胞病变并对乳鼠致病;其基因组为登革1型病毒特异的RNA分子,经鉴定为登革1型病毒;此次分离的登革1型病毒与1980年分离的同型毒株在致细胞产生病变的时间和严重程度,蚀斑的大小、形态以及致乳鼠发病的时间等生物学性质上有所不同。结论：2006年广州流行登革热病原为登革1型病毒,且与1980年分离的同型毒株在生物学性质方面存在明显差异。