微生物所方卫国教授实验室在PNAS发表论文

寄生虫改变寄主行为是一个令科学家和公众都着迷的生物学现象，因为这涉及到是否真的有自由意志这个核心的哲学问题，但有关分子机制一直都没有阐明。蝗虫喜欢独居，并相互避开，表现出反社交的行为。但受到特定的外界刺激之后，它们会改变行为方式，呈现出社会群居行为。群居的蝗虫集体迁飞，吃光一路上的所有植物，形成令人生畏的蝗灾。一种叫微孢子虫的寄生真菌感染蝗虫后，可以使独居的蝗虫继续独居，使群居的蝗虫回到独居。以这个蝗虫/微 孢子为研究模型，浙江大学方卫国教授研究组和中国农业大学石旺鹏教授研究组通过长期合作，阐明了微孢子虫控制蝗虫行为的机制。微孢子虫通过改变蝗虫的免疫系统和肠道的化学性质，杀死大量的肠道细菌（参与合成召集蝗虫聚集的信息素），这扰乱了蝗虫的神经系统，诱导和保持群居行为的神经递质（serotonin和dopamine）的水平下降，最终导致行为异常。该研究成果以Direct submission的形式发表在Proceedings of the National Academy of the Sciences of the United States of America上（美国科学院院报）。该文将被“In This Issue”评论 （a front section of the print journal）。

http://www.pnas.org/content/early/2014/01/08/1314009111.full.pdf+html

由于该文可能会引起新闻界的兴趣，所以PNAS为它准备了press release tip （如下）

Gut parasites may prevent locust swarms

A locust gut parasite may act to inhibit production of pheromones and neurotransmitters that can initiate swarming, according to a study. A swarm of locusts, often inflicting devastating agricultural damage, can be triggered and sustained by a mix of aggregation pheromones that induce otherwise solitary locusts to gather into a migratory group. To investigate the effect of a common microsporidian locust parasite, Paranosema (Nosema) locustae, on swarming behavior, Weiguo Fang and colleagues exposed locusts to chambers containing fecal volatile chemicals from both healthy locusts and locusts infected with P. locustae. The locusts aggregated more in the chamber with uninfected volatiles, and also displayed a stronger antennal response to uninfected fecal volatiles than to those from infected locusts. Infected locusts produced fewer fecal volatiles than healthy locusts, with volatile pheromone production decreasing as the parasitic infection progressed. The authors found that P. locustae acidifies the locust hindgut, inhibiting growth of the gut bacteria that may act to fight off parasite infection and produce aggregation pheromones. Further, infected locusts produced lower levels of the neurotransmitters serotonin, which can initiate a swarm, and dopamine, which can sustain swarming behavior, according to the authors. The results suggest that by changing the chemistry of the locust gut, P. locustae acts to inhibit locust swarming behavior.

Article #13-14009: “Unveiling the mechanism by which microsporidian parasites prevent locust’s swarm behavior,” by Wangpeng Shi et al.

MEDIA CONTACT: Weiguo Fang, Institute of Microbiology, Zhejiang University, Hangzhou, Zhejiang, CHINA; tel: +86-571-88206668; e-mail: <wfang1@zju.edu.en>

 

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