Haine Eleanor R, Moret Yannick, Siva-Jothy Michael T, Rolff Jens
Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
Science. 2008 Nov 21;322(5905):1257-9. doi: 10.1126/science.1165265.
During 400 million years of existence, insects have rarely succumbed to the evolution of microbial resistance against their potent antimicrobial immune defenses. We found that microbial clearance after infection is extremely fast and that induced antimicrobial activity starts to increase only when most of the bacteria (99.5%) have been removed. Our experiments showed that those bacteria that survived exposure to the insect's constitutive immune response were subsequently more resistant to it. These results imply that induced antimicrobial compounds function primarily to protect the insect against the bacteria that persist within their body, rather than to clear microbial infections. These findings suggest that understanding of the management of antimicrobial peptides in natural systems might inform medical treatment strategies that avoid the risk of drug resistance.
在长达4亿年的生存历程中，昆虫极少因微生物对其强大的抗菌免疫防御产生抗性进化而屈服。我们发现，感染后微生物的清除速度极快，且只有当大部分细菌（99.5%）被清除后，诱导产生的抗菌活性才开始增强。我们的实验表明，那些在接触昆虫固有免疫反应后存活下来的细菌，随后对该反应更具抗性。这些结果意味着，诱导产生的抗菌化合物主要功能是保护昆虫抵御体内持续存在的细菌，而非清除微生物感染。这些发现表明，了解自然系统中抗菌肽的调控机制或许能为避免耐药风险的医学治疗策略提供参考。
