title: Paenibacillus larvae enolase as a virulence factor in honeybee larvae infection.
abstract: Paenibacillus larvae is a gram-positive spore-forming bacteria, causative agent of American Foulbrood (AFB), a severe disease affecting larvae of the honeybee Apis mellifera. In an attempt to detect potential virulence factors secreted by P. larvae, we identified an enolase among different secreted proteins. Although this protein is a cytosolic enzyme involved in glycolytic pathways, it has been related to virulence. The aim of the present work was to evaluate its role during the infection of honeybee larvae. Toxicity assays showed that enolase was highly toxic and immunogenic to honeybee larvae. Its production was detected inside P. larvae vegetative cells, on the surface of P. larvae spores and secreted to the external growth medium. P. larvae enolase production was also confirmed in vivo, during the infection of honeybee larvae. This protein was able to hydrolyze milk proteins as described for P. larvae, suggesting that could be involved in larval degradation, maybe through the plasmin(ogen) system. These results suggest that P. larvae enolase may have a role in virulence and could contribute to a general insight about insect-pathogen interaction mechanisms.
authors.affiliation: Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable, Avda. Italia 3318, C.P. 11600, Montevideo, Uruguay. karina@iibce.edu.uy
authors.forename: Karina
authors.initials: K
authors.lastname: Antúnez
authors.forename: Matilde
authors.initials: M
authors.lastname: Anido
authors.forename: Daniela
authors.initials: D
authors.lastname: Arredondo
authors.forename: Jay D
authors.initials: JD
authors.lastname: Evans
authors.forename: Pablo
authors.initials: P
authors.lastname: Zunino
mesh_terms: D000818:Animals; D001516:Bees / Q000187:drug effects / Q000276:immunology / Q000382:microbiology*; D005455:Fluorescent Antibody Technique; D007106:Immune Sera / Q000032:analysis; D017404:In Situ Hybridization, Fluorescence; D007814:Larva / Q000187:drug effects / Q000382:microbiology; D008894:Milk Proteins / Q000378:metabolism; D056507:Paenibacillus / Q000201:enzymology*; D010751:Phosphopyruvate Hydratase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000633:toxicity; D013171:Spores, Bacterial / Q000201:enzymology; D037521:Virulence Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000633:toxicity
chemical_list: D007106:Immune Sera; D008894:Milk Proteins; D037521:Virulence Factors; D010751:Phosphopyruvate Hydratase