寄主植物挥发物对梨小食心虫受孕雌虫的引诱作用初探

梨小食心虫Grapholita molesta(Busck),是一种世界性的蛀果害虫。利用产卵选择试验研究了15种寄主植物挥发物对梨小食心虫受孕雌虫的产卵引诱活性。室内试验表明:受孕雌虫对不同挥发物的产卵选择趋性不同,其中对叶醇和己酸丁酯表现出明显的产卵选择趋性。为验证寄主挥发物对受孕雌虫的实际诱捕效果,进行了田间诱捕试验。结果发现,挥发物中己酸丁酯、苯甲腈、叶醇、E-2-己烯醛以及乙酸己酯诱捕到的雌虫均为受孕雌虫,显著高于空白对照及其他物质,其中己酸丁酯的平均诱捕量最多,苯甲腈次之,E-2-己烯醛、乙酸己酯这两种物质的平均诱捕量分别为第三、第四,叶醇的诱捕量低于乙酸己酯,其余物质的诱捕量均较低。综合室内及田间试验结果发现,寄主植物挥发物对受孕雌虫的引诱作用也随它们之间的作用距离表现出一定的差异性。     

Microboring organisms in living stylasterid corals (Cnidaria,Hydrozoa)

Microboring or euendolithic microorganisms, which colonize and penetrate various carbonate substrates, are abundant in coral reef ecosystems and play a major role in reef carbonate dissolution. A few studies reported the presence of euendoliths in stylasterid coral skeletons but the biological identity, distribution and abundance of these microorganisms remain largely unknown. Observations of over 100 stylasterid colonies, collected in the Indo-Pacific area, revealed for the first time that the association between these corals and euendolith organisms appears to be quite common in shallow tropical waters. The most abundant euendolith was identified as a cryptic stage in the development of the rhodophyte Porphyra (Conchocelis stage). The euendoliths were observed in the skeletons of seven species of three genera (four Stylaster, two Distichopora and one Lepidotheca). The presence of euendoliths inside skeletons conferred a particular colour to the studied stylasterid corals. Distribution and abundance of microborings varied significantly among stylasterid species and among branches of a single colony and so did the colour of their skeletons. Colonization of skeletons and the associated colour distribution were almost uniform in some stylasterids, forming an upward gradually diminishing or sharply limited gradient. This study shows that patterns of euendolith colonization and growth in stylasterid skeletons may depend on the stage of the euendolith development as well as on their environmental requirements such as light exposure.     

MOLECULAR CHARACTERIZATION OF AUTOPHAGY‐RELATED GENE 5 FROM Spodoptera exigua AND EXPRESSION ANALYSIS UNDER VARIOUS STRESS CONDITIONS

Autophagy is not only involved in development, but also has been proved to attend immune response against invading pathogens. Autophagy protein 5 (ATG5) is an important autophagic protein, which plays a crucial role in autophagosome elongation. Although ATG5 has been well studied in mammal, yeast, and Drosophila, little is known about ATG5 in lepidopteran insects. We cloned putative SeAtg5 gene from Spodoptera exigua larvae by the rapid amplification of cDNA ends method, and its characteristics and the influences of multiple exogenous factors on its expression levels were then investigated. The results showed that the putative S. exigua SeATG5 protein is highly homologous to other insect ATG5 proteins, which has a conserved Pfm domain and multiple phosphorylation sites. Next, fluorescence microscope observation showed that mCherry‐SeATG5 was distributed in both nucleus and cytoplasm of Spodoptera litura Sl‐HP cells and partially co‐localized with BmATG6‐GFP, but it almost has no significant co‐localization with GFP‐HaATG8. Then, the Western blot analysis demonstrated that GFP‐SeATG5 conjugated with ATG12. Moreover, real‐time PCR revealed that its expression levels significantly increased at the initiation of pupation and the stage of adult. In addition, the expression levels of SeAtg5 can be enhanced by the starvation, UV radiation, and infection of baculovirus and bacterium. However, the expression levels of SeAtg5 decreased at 24 h post treatments in all these treatments except in starvation. These results suggested that SeATG5 might be involved in response of S. exigua under various stress conditions.