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Title: Secreted and immunogenic proteins produced by the honey bee bacterial pathogen, Paenibacillus larvae

item ANTUNEZ, KARINA - University Of Montevideo
item ANIDO, MATILDE - University Of Montevideo
item Evans, Jay
item ZUNINO, PABLO - University Of Montevideo

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2010
Publication Date: 12/10/2010
Citation: Antunez, K., Anido, M., Evans, J.D., Zunino, P. 2010. Secreted and immunogenic proteins produced by the honey bee bacterial pathogen, Paenibacillus larvae. Veterinary Microbiology. 141:385-389.

Interpretive Summary: American foulbrood (AFB) remains an important and reportable brood disease of honey bees. Past work indicates that the bacterium causing AFB secretes proteins that then attack the bee gut. These proteins are poorly characterized, and we carried out these experiments to see which proteins are most important. Using data from the P. larvae genome project we were able to identify proteins that seem like good candidates to explain how this bacterium causes honey bee disease. The results from this work have bearing on bee immunity and the management and breeding steps bee breeders can use to reduce this and other bee diseases.

Technical Abstract: American Foulbrood is a severe disease affecting larvae of honeybee Apis mellifera, causing significant decrease in the honeybee population, beekeeping industries and agricultural production. In spite of its importance, little is known about the virulence factors secreted by Paenibacillus larvae during larval infection. The aim of the present work was to perform a first approach to the identification and characterization of P. larvae secretome. P. larvae secreted proteins were analyzed by SDS-PAGE and identified by MALDI-TOF. Protein toxicity was evaluated using an experimental model based on feeding of A. mellifera larvae and immunogenicity was evaluated by Western blot, using an antiserum raised against cells and spores of P. larvae. Ten different proteins were identi.ed among P. larvae secreted proteins, including proteins involved in transcription, metabolism, translation, cell envelope, transport, protein folding, degradation of polysaccharides and motility. Although most of these proteins are cytosolic, many of them have been previously detected in the extracellular medium of different Bacillus spp. cultures and have been related to virulence. The secreted proteins resulted highly toxic and immunogenic when larvae were exposed using an experimental model. This is the first description of proteins secreted by the honeybee pathogen P. larvae. This information may be relevant for the elucidation of bacterial pathogenesis mechanisms.