Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable, Avda. Italia 3318, C.P. 11600, Montevideo, Uruguay.
Vet Microbiol. 2011 Jan 10;147(1-2):83-9. doi: 10.1016/j.vetmic.2010.06.004. Epub 2010 Jun 15.
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.
幼虫芽孢杆菌是一种革兰氏阳性产芽孢细菌,是美国幼虫腐烂病(AFB)的病原体,这种严重的疾病会影响蜜蜂(Apis mellifera)的幼虫。为了尝试检测幼虫芽孢杆菌分泌的潜在毒力因子,我们在不同的分泌蛋白中鉴定出一种烯醇酶。尽管这种蛋白质是一种参与糖酵解途径的胞质酶,但它与毒力有关。本工作的目的是评估其在蜜蜂幼虫感染过程中的作用。毒性测定表明,烯醇酶对蜜蜂幼虫具有高度毒性和免疫原性。它的产生在幼虫芽孢杆菌营养细胞内、幼虫芽孢杆菌孢子表面被检测到,并分泌到外部生长培养基中。在感染蜜蜂幼虫的过程中,也在体内证实了幼虫芽孢杆菌烯醇酶的产生。这种蛋白质能够像幼虫芽孢杆菌那样水解乳蛋白,这表明它可能参与幼虫的降解,也许是通过纤溶酶(原)系统。这些结果表明,幼虫芽孢杆菌烯醇酶可能在毒力中起作用,并有助于深入了解昆虫-病原体相互作用的机制。