家蚕蜕皮液蛋白质双向电泳及质谱分析

蜕皮液是存在于新旧表皮之间的一层液体,在昆虫蜕皮和变态发育的过程中发挥了重要的作用。为进一步探究家蚕蜕皮液的功能,利用双向电泳技术对家蚕预蛹期及羽化前期的蜕皮液的蛋白质进行了分析,结果表明,预蛹期及羽化前期的蜕皮液中分别可以检测出超过200个蛋白点,它们主要分布在等电点4-9、分子量10-180 kDa之间。利用MALDI TOF/TOF对羽化前期蜕皮液的42个蛋白点进行了鉴定分析,结果表明34个蛋白点成功得到了鉴定,它们主要包括载脂蛋白类、蛋白酶与蛋白酶抑制剂、免疫相关蛋白、几丁质结合蛋白等,部分蛋白在预蛹期的蜕皮液和羽化前的蜕皮液之间存在明显的差异表达。为了进一步验证蛋白质组分析的结果,对其中1个差异表达明显的蛋白质Apolipoprotein D进行了进一步的分析,Q-PCR的结果表明,该蛋白主要在化蛹第1–4天存在高表达,其在羽化前蜕皮液中的高度累积暗示了它可能参与了家蚕羽化变态的过程。以上研究结果进一步丰富了人们对蜕皮液蛋白质的认识,为深入研究蜕皮液蛋白质的功能提供了一些参考。     

Bioefficacy of root extracts of a medicinal plant,Withania somnifera (Dunal) against a polyphagous pest,Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae)

Oral administration of root extracts of a medicinal plant, Ashwagandha (Withania somnifera) to last instar larvae of a polyphagous pest, Spodoptera litura resulted into abnormal morphogenesis and the effects comprised mortality, delay in larval-pupal and pupal-adult ecdysis, ecdysial stasis, formation of larval-pupal and pupal-adult intermediates, reduced pupation and formation of abnormal pupae, complete suppression of normal adult emergence and formation of adultoids. These effects are similar to those produced by the administration of JHAs and may be due to interference with the normal hormonal mechanism of moulting and metamorphosis.     

家蚕蛹变态期丝腺组织的退化与细胞凋亡特征

利用形态学观察方法、分子生物学检测方法以及20-羟基蜕皮酮(20-hydroxyecdysone)和放线菌酮(cycloheximide)体外培养方法, 研究了家蚕Bombyx mori 蛹变态期丝腺组织的退化与细胞凋亡特征。显微镜的观察显示家蚕丝腺的逐渐退化发生在吐丝期间。DNA梯度电泳的分析表明程序性细胞死亡(programmed cell death)可能伴随发生在丝腺的退化过程中。在离体培养条件下, 用20-羟基蜕皮酮处理5龄第6天幼虫的丝腺, 导致的细胞凋亡提前于对照, 提示在进入蛹变态期前, 20-羟基蜕皮酮提早激发了介导家蚕丝腺细胞凋亡与水解机制的遗传调控级联系统。上述结果表明, 20-羟基蜕皮酮能够诱导家蚕丝腺组织在蛹变态期发生程序性细胞死亡。     

Effect of excretory-secretory products of some fouling organisms on settling and metamorphosis of the larvae of <Emphasis Type="Italic">Styela rustica</Emphasis> (Ascidiae)

The effect of the excretory-secretory products of some fouling animals on the settling and metamorphosis of larvae of the solitary ascidian Styela rustica was assessed. The substances secreted by the sponge Halichondria panicea stimulated settling of larvae, but concurrently blocked their metamorphosis. The excretory-secretory products of the mussel Mytilus edulis and the ascidian Molgula citrine did not affect settling of the S. rustica larvae but impeded their subsequent development. Water conditioned by the bivalve Hiatella arctica, stimulated settling and, apparently, metamorphosis of the larvae of S. rustica. The chemical substances produced by adult individuals of S. rustica facilitated settling of conspecific larvae but slightly delayed their metamorphosis.     

Crossing habitat boundaries: coupling dynamics of ecosystems through complex life cycles

Ecosystems are often indirectly connected through consumers with complex life cycles (CLC), in which different life stages inhabit different ecosystems. Using a structured consumer resource model that accounts for the independent effects of two resources on consumer growth and reproductive rates, we show that such indirect connections between ecosystems can result in alternative stable states characterized by adult-dominated and juvenile-dominated consumer populations. As a consequence, gradual changes in ecosystem productivity or mortality rates of the consumer can lead to dramatic and abrupt regime shifts across different ecosystems, hysteresis and counterintuitive changes in the consumer abundances. Whether these counter intuitive or abrupt responses occur depend on the relative productivity of both habitats and which consumer life-stage inhabits the manipulated ecosystem. These results demonstrate the strong yet complex interactions between ecosystems coupled through consumers with CLC and the need to think across ecosystems to reliably predict the consequences of natural or anthropogenic changes.     

饥饿和再投喂对青蛤(Cyclina sinensis)幼虫生长、存活及变态的影响

在温度18.2～20.6℃,盐度23～25,pH 7.96～8.14 的条件下,研究了饥饿和再投喂对青蛤幼虫生长、存活及变态的影响.结果表明:在饥饿状态下,幼虫具有生长现象,且随着饥饿时间的延长,壳长逐渐接近一个常值而不再生长;幼虫可以由面盘幼虫发育到足面盘幼虫.随饥饿时间延长存活率下降;且足面盘幼虫及其变态规格、单水管稚贝规格随着饥饿时间延长而减小;幼虫的不可逆点(PNR)为12.48d;延迟变态时间长达12.7d.饥饿后再投喂相同的时间,幼虫能够恢复生长,存活的幼虫能够变态;稚贝表现出补偿生长现象,以壳长作为衡量标准,完全补偿生长能力依次为:S10＞S11＞S12＞S1＞S2＞S3;超补偿生长能力依次为:S9＞S8＞S7＞S6＞S5＞S4.     

Isolation,characterization and molecular cloning of new antimicrobial peptides belonging to the brevinin-1 and temporin families from the skin of Hylarana latouchii (Anura: Ranidae)

Around 40 species of Hylarana amphibians are distributed in tropical and subtropical Asia, and Chinese broad-folded frog, Hylarana latouchii (Boulenger, 1899) is one of them. In this study, six different cDNAs encoding four novel antimicrobial peptide precursors were cloned by screening the cDNA library of the Chinese broad-folded frog skin. The protein sequence analysis demonstrated that two deduced peptides belong to the brevinin-1 family, and the other two belong to temporin family of amphibian antimicrobial peptides. Thus, they were named as brevinin-1LT1 (FMGSALRIAAKVLPAALCQIFKKC), brevinin-1LT2 (FFGSVLKVAAKVLPAALCQIFKKC), temporin-LT1 (FLPGLIAGIAKML–NH₂) and temporin-LT2 (FLPIALKALGSIFPKIL–NH₂), respectively. Furthermore, brevinin-1LT1 and temporin-LT1 were purified by HPLC from the skin secretion of H. latouchii. In this work, all the peptides kill microbes by membrane-disturbing mechanisms, and this procedure was visualized via scanning electron microscopy (SEM).     

果蝇变态过程中的细胞凋亡和细胞自噬

程序化细胞死亡(programmed cell death,PCD)分为I型PCD细胞凋亡(apoptosis)和II型PCD细胞自噬(autophagy)。果蝇等完全变态昆虫有2种类型的器官:即细胞内分裂器官(如脂肪体、表皮、唾液腺、中肠、马氏管等)和有丝分裂器官(复眼、翅膀、足、神经系统等)。在昆虫变态过程中,细胞内分裂器官进行器官重建,幼虫器官大量发生细胞凋亡和细胞自噬到最后完全消亡,同时成虫器官由干细胞从新生成;而有丝分裂器官则由幼虫器官直接发育为成虫器官。在果蝇等昆虫的变态过程中,细胞凋亡和细胞自噬在幼虫器官的死亡和成虫器官的生成中发挥了非常重要的作用。文章简要介绍细胞凋亡和细胞自噬在果蝇变态过程中的生理功能和分子调控机制。