Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano, 20133 Milan, Italy.
Environ Microbiol. 2009 Dec;11(12):3252-64. doi: 10.1111/j.1462-2920.2009.02048.x. Epub 2009 Sep 4.
Bacterial symbionts of insects have been proposed for blocking transmission of vector-borne pathogens. However, in many vector models the ecology of symbionts and their capability of cross-colonizing different hosts, an important feature in the symbiotic control approach, is poorly known. Here we show that the acetic acid bacterium Asaia, previously found in the malaria mosquito vector Anopheles stephensi, is also present in, and capable of cross-colonizing other sugar-feeding insects of phylogenetically distant genera and orders. PCR, real-time PCR and in situ hybridization experiments showed Asaia in the body of the mosquito Aedes aegypti and the leafhopper Scaphoideus titanus, vectors of human viruses and a grapevine phytoplasma respectively. Cross-colonization patterns of the body of Ae. aegypti, An. stephensi and S. titanus have been documented with Asaia strains isolated from An. stephensi or Ae. aegypti, and labelled with plasmid- or chromosome-encoded fluorescent proteins (Gfp and DsRed respectively). Fluorescence and confocal microscopy showed that Asaia, administered with the sugar meal, efficiently colonized guts, male and female reproductive systems and the salivary glands. The ability in cross-colonizing insects of phylogenetically distant orders indicated that Asaia adopts body invasion mechanisms independent from host-specific biological characteristics. This versatility is an important property for the development of symbiont-based control of different vector-borne diseases.
昆虫的细菌共生体被提议用于阻止媒介传播的病原体的传播。然而，在许多媒介模型中，共生体的生态学及其在共生控制方法中具有重要意义的跨宿主定殖能力知之甚少。在这里，我们表明，先前在疟疾蚊子媒介按蚊中发现的醋酸菌 Asaia 也存在于并能够跨定殖其他具有不同亲缘关系的属和目的吸食糖的昆虫中。PCR、实时 PCR 和原位杂交实验表明，Asaia 存在于蚊子埃及伊蚊和叶蝉 Scaphoideus titanus 的体内，分别是人类病毒和葡萄植原体的媒介。使用从按蚊或埃及伊蚊中分离的 Asaia 菌株，并标记有质粒或染色体编码的荧光蛋白（分别为 Gfp 和 DsRed），记录了 Ae. aegypti、An. stephensi 和 S. titanus 体内的跨定殖模式。荧光和共聚焦显微镜显示，Asaia 在给予糖餐后，能够有效地定植肠道、雄性和雌性生殖系统以及唾液腺。从亲缘关系较远的目昆虫中进行跨定殖的能力表明，Asaia 采用了与宿主特异性生物学特征无关的身体入侵机制。这种多功能性是开发基于共生体的不同媒介传播疾病控制的重要特性。
