title: Delayed larval development in Anopheles mosquitoes deprived of Asaia bacterial symbionts.
abstract: BACKGROUND
  In recent years, acetic acid bacteria have been shown to be frequently associated with insects, but knowledge on their biological role in the arthropod host is limited. The discovery that acetic acid bacteria of the genus Asaia are a main component of the microbiota of Anopheles stephensi makes this mosquito a useful model for studies on this novel group of symbionts. Here we present experimental results that provide a first evidence for a beneficial role of Asaia in An. stephensi.
  
  
  RESULTS
  Larvae of An. stephensi at different stages were treated with rifampicin, an antibiotic effective on wild-type Asaia spp., and the effects on the larval development were evaluated. Larvae treated with the antibiotic showed a delay in the development and an asynchrony in the appearance of later instars. In larvae treated with rifampicin, but supplemented with a rifampicin-resistant mutant strain of Asaia, larval development was comparable to that of control larvae not exposed to the antibiotic. Analysis of the bacterial diversity of the three mosquito populations confirmed that the level of Asaia was strongly decreased in the antibiotic-treated larvae, since the symbiont was not detectable by PCR-DGGE (denaturing gradient gel electrophoresis), while Asaia was consistently found in insects supplemented with rifampicin plus the antibiotic-resistant mutant in the diet, and in those not exposed to the antibiotic.
  
  
  CONCLUSIONS
  The results here reported indicate that Asaia symbionts play a beneficial role in the normal development of An. stephensi larvae.
authors.forename: Bessem
authors.initials: B
authors.lastname: Chouaia
authors.forename: Paolo
authors.initials: P
authors.lastname: Rossi
authors.forename: Sara
authors.initials: S
authors.lastname: Epis
authors.forename: Michela
authors.initials: M
authors.lastname: Mosca
authors.forename: Irene
authors.initials: I
authors.lastname: Ricci
authors.forename: Claudia
authors.initials: C
authors.lastname: Damiani
authors.forename: Ulisse
authors.initials: U
authors.lastname: Ulissi
authors.forename: Elena
authors.initials: E
authors.lastname: Crotti
authors.forename: Daniele
authors.initials: D
authors.lastname: Daffonchio
authors.forename: Claudio
authors.initials: C
authors.lastname: Bandi
authors.forename: Guido
authors.initials: G
authors.lastname: Favia
mesh_terms: D016947:Acetobacteraceae / Q000187:drug effects; D000818:Animals; D000852:Anopheles / Q000187:drug effects / Q000254:growth & development* / Q000382:microbiology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D007814:Larva / Q000187:drug effects; D012293:Rifampin / Q000494:pharmacology*; D013559:Symbiosis / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D012293:Rifampin