Bacteria of the genus Asaia:: A potential paratransgenic weapon against malaria
Bacteria of the genus Asaia:: A potential paratransgenic weapon against malaria
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DOI：
10.1007/978-0-387-78225-6_4
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发表时间：
2008-01-01
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影响因子：
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通讯作者：
Daffonchio, Daniele
中科院分区：
文献类型：
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作者：
Favia, Guido;Ricci, Irene;Daffonchio, Daniele
共生细菌已被提议作为控制虫媒疾病的工具。这种共生体的基本要求是在昆虫体内的优势、流行和稳定。迄今为止，在按蚊（人类疟疾的传播媒介）中描述的大多数细菌共生体都缺乏这些特征。我们描述了一种α-变形杆菌属Asaia，它稳定地与几个按蚊物种，并占主导地位的身体内的一个。史蒂芬西Asaia表现出所有需要的生态特性，使其成为最佳的候选人，迄今为止，为开发一个paratransgenic的方法来操纵蚊子的媒介能力。Asaia的主要特点是：（i）蚊子相关微生物区系内的优势，如通过16 S rRNA基因文库和定量真实的时间聚合酶链反应（qRT-PCR）中的克隆流行率所示;（ii）在无细胞培养基中的可培养性;（iii）易于用外源DNA转化;和（iv）在幼虫和成虫蚊子体内的广泛分布，如通过透射电子显微镜和原位杂交实验所揭示。使用绿色荧光蛋白（GFP）标记的Asaia菌株，已经有可能表明它有效地定殖疟疾寄生虫发育和传播所必需的所有蚊子身体器官，包括雌性肠道和唾液腺。Asaia还被发现大量定植于成年蚊子的幼虫肠道和雄性生殖系统。此外，交配实验显示了共生控制所需的另一个关键特征，即共生体通过多种机制向后代的高传播潜力。Asaia能够在成虫前期和成虫阶段通过进食期间的口腔途径进行水平感染，并在成虫交配期间通过性病模式进行感染。此外，Asaia从母亲垂直传播到后代，表明它可以在自然蚊子种群中迅速传播。
Symbiotic bacteria have been proposed as tools for control of insect-borne diseases. Primary requirements for such symbionts are dominance, prevalence and stability within the insect body. Most of the bacterial symbionts described to date in Anopheles mosquitoes, the vector of malaria in humans, have lacked these features. We describe an alpha-Proteobacterium of the genus Asaia, which stably associates with several Anopheles species and dominates within the body of An. stephensi. Asaia exhibits all the required ecological characteristics making it the best candidate, available to date, for the development of a paratransgenic approach for manipulation of mosquito vector competence. Key features of Asaia are: (i) dominance within the mosquito-associated microflora, as shown by clone prevalence in 16S rRNA gene libraries and quantitative real time Polymerase Chain Reaction (qRT-PCR); (ii) cultivability in cell-free media; (iii) ease of transformation with foreign DNA and (iv) wide distribution in the larvae and adult mosquito body, as revealed by transmission electron microscopy, and in situ-hybridization experiments. Using a green fluorescent protein (GFP)-tagged Asaia strain, it has been possible to show that it effectively colonizes all mosquito body organs necessary for malaria parasite development and transmission, including female gut and salivary glands. Asaia was also found to massively colonize the larval gut and the male reproductive system of adult mosquitoes. Moreover, mating experiments showed an additional key feature necessary for symbiotic control, the high transmission potential of the symbiont to progeny by multiple mechanisms. Asaia is capable of horizontal infection through an oral route during feeding both in preadult and adult stages and through a venereal pattern during mating in adults. Furthermore, Asaia is vertically transmitted from mother to progeny indicating that it could quickly spread in natural mosquito populations.