一項(xiàng)研究報(bào)告說,，一種寄生蜂的幼蟲使用殺菌劑對它們的美洲蟑螂宿主進(jìn)行消毒。Gudrun Herzner及其同事分析了美洲蟑螂的外表面和內(nèi)部組織,，并且確定了它們含有粘質(zhì)沙雷氏菌（Serratia marcescens）和其他病原體,。這組作者然后分析了寄生蜂扁頭泥蜂（Ampulex compressa）的幼蟲分泌的液滴，結(jié)果發(fā)現(xiàn)了這種液滴含有強(qiáng)大的殺菌劑,，能保護(hù)宿主不受粘質(zhì)沙雷氏菌和其他細(xì)菌與真菌的侵害,。這種天然消毒劑是有用處的，因?yàn)檫@種蜂的雌性成蟲在把一枚卵粘在這種蟑螂的腿上之前,，會蜇這種蟑螂并且把它們拖到一個隱蔽的地點(diǎn),。在大約7天之后，孵化出的幼蟲運(yùn)動到這種蟑螂體內(nèi)并以它的內(nèi)臟為食,。在幾乎完整地吃掉這種蟑螂之后,，這種幼蟲會在蟑螂尸體內(nèi)化作一個繭，然后變成一只蜂,。此前的研究已經(jīng)確定了一種來自這種幼蟲的物質(zhì)micromolide可能作為一種有潛力的抗結(jié)核藥物,。其他研究也已經(jīng)發(fā)現(xiàn)了另外的一些昆蟲——諸如埋葬甲蟲——能夠?qū)λ鼈兊挠紫x的宿主進(jìn)行消毒。這組作者說,，人類因此不是唯一一種試圖應(yīng)對與被污染的食物來源相關(guān)的問題的生物,。(生物谷Bioon.com)

doi: 10.1073/pnas.1213384110
PMC:
PMID:
Larvae of the parasitoid wasp Ampulex compressa sanitize their host, the American cockroach, with a blend of antimicrobials

Gudrun Herznera,1, Anja Schlechta, Veronika Dollhofera, Christopher Parzefalla, Klaus Harrarb, Andreas Kreuzerb, Ludwig Pilslb, and Joachim Rutherc

Food resources contaminated with spoilage or pathogenic microorganisms pose severe problems to all higher organisms. Here, we describe a food-hygienic strategy of the emerald cockroach wasp Ampulex compressa. The wasp larvae develop on and inside the American cockroach Periplaneta americana, a host that can harbor various putrefactive microbes, as well as human and insect pathogens. From P. americana, we isolated the Gram-negative bacterium Serratia marcescens, which is a potent entomopathogen that can rapidly kill insect larvae. It is also known as a food contaminant and as an opportunistic human pathogen. Using behavioral observations and chemical analyses, we demonstrated that A. compressa larvae impregnate their cockroach hosts from inside with large amounts of an oral secretion containing a blend of γ-lactones and isocoumarins with (R)-(-)-mellein [(R)-(-)-3,4-diydro-8-hydroxy-3-methylisocoumarin] and micromolide [(4R,9Z)-octadec-9-en-4-olide] as dominant components. We fractionated hexane extracts of the secretion and investigated the antimicrobial properties of the fraction containing the lactones and isocoumarins, as well as of synthetic (R)-(-)-mellein and micromolide, against S. marcescens and a Gram-positive bacterium, Staphylococcus hyicus, in broth microdilution assays. The test fraction inhibited growth of both tested bacteria. The activity of the fraction against S. marcescens was explained by (R)-(-)-mellein alone, and the activity against S. hyicus was explained by the combined action of (R)-(-)-mellein and micromolide. Our data suggest that the specific combination of antimicrobials in the larval secretion provides an effective frontline defense against the unpredictable spectrum of microbes that A. compressa larvae may encounter during their development inside their cockroach hosts.