J Bacteriol 2007, 189:646–649.PubMedCrossRef Authors’ contributions All authors made substantial contributions to conception, design, acquisition of data, or analysis and interpretation of data. They were involved in drafting the manuscript and revising it, and have given final approval of the version to be published. Competing interests

The authors declare that they have no competing interests.”
“Background Symbiotic bacteria are widespread in insects in which they play different roles, from providing nutrients, to affecting reproduction and speciation, among others [1]. Mosquitoes are vectors of a variety of infectious diseases that have a dramatic impact on public health, like malaria, yellow fever, dengue and chikungunya. Despite the common knowledge that these diseases are caused by microorganisms, Selleckchem Natural Product Library the interactions between mosquitoes and their overall microbial community have not been deeply investigated. Acetic acid bacteria (AAB) are traditionally isolated from fermented foods and plant material [2, 3]. In the last years, AABs have been described as emerging

symbionts of insects being found associated especially with those with a sugar-feeding habit [4, 5]. AAB of the genus Asaia have been shown to be stably associated with larvae and adults of the malaria mosquito vectors An. stephensi, An. maculipennis and An. gambiae [6, 7] where they form a main component of the mosquito-associated microbiota. Asaia is a versatile symbiont being selleck inhibitor capable of cross-colonizing insects from phylogenetically distant taxa [8] and of vertical, venereal and paternal transmission [9]. However little FRAX597 is known about the effect of Asaia on the host. In Drosophila melanogaster AAB have been shown to regulate the microbiota homeostasis, by keeping under control pathogenic species following a Tyrosine-protein kinase BLK fine-tuning of the host immune response [10, 11]. In An. gambiae, it has been shown that Asaia titer in the host body is kept under control of the

innate immune system and it massively proliferates in the hemolymph when the AgDscam component of the immune response is silenced [12]. Asaia spp. have been shown to fix nitrogen [13] and it might be suggested that the role of these symbionts is to provide the host insect with organic nitrogen, a capacity already proposed for gut symbionts in other insect models [14]. A frequently used strategy to investigate the effect of microbial symbionts on the host consists of their removal using antibiotic treatments to observe the effect on the host vitality and fitness [15, 16]. A main limit of such a strategy is the lack of a suitable control, since the effects observed could be caused by direct effects of the antibiotic on the insect and/or on other components of the microbiota. Here we have adopted a different strategy, setting control experiments with Asaia resistant to the antibiotic treatment. By using this strategy we showed that Asaia contributes positively to the normal larval development of An. stephensi.