Potential costs of bacterial infection on storage protein gene expression and reproduction in queenless Apis mellifera worker bees on distinct dietary regimes.
Insects are able to combat infection by initiating an efficient immune response that involves synthesizing antimicrobial peptides and a range of other defense molecules. These responses may be costly to the organism, resulting in it exploiting endogenous resources to maintain homeostasis or support defense to the detriment of other physiological needs. We used queenless worker bees on distinct dietary regimes that may alter hemolymph protein storage and ovary activation to investigate the physiological costs of infection with Serratia marcescens. The expression of the genes encoding the storage proteins vitellogenin and hexamerin 70a, the vitellogenin receptor, and vasa (which has a putative role in reproduction), was impaired in the infected bees. This impairment was mainly evident in the bees fed beebread, which caused significantly higher expression of these genes than did royal jelly or syrup, and this was confirmed at the vitellogenin and hexamerin 70a protein levels. Beebread was also the only diet that promoted ovary activation in the queenless bees, but this activation was significantly impaired by the infection. The expression of the genes encoding the storage proteins apolipophorins-I and -III and the lipophorin receptor was not altered by infection regardless the diet provided to the bees. Similarly, the storage of apolipophorin-I in the hemolymph was only slightly impaired by the infection, independently of the supplied diet. Taken together these results indicate that, infection demands a physiological cost from the transcription of specific protein storage-related genes and from the reproductive capacity.
Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, São Paulo, Brazil. anete.lourenco@ufvjm.edu.br
Anete Pedro
AP
Lourenço
Juliana Ramos
JR
Martins
Karina Rosa
KR
Guidugli-Lazzarini
Liliane Maria Fróes
LM
Macedo
Márcia Maria Gentile
MM
Bitondi
Zilá Luz Paulino
ZL
Simões
D000818:Animals; D001516:Bees / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D004032:Diet; D005260:Female; D054884:Host-Pathogen Interactions; D019476:Insect Proteins / Q000378:metabolism*; D010053:Ovary / Q000502:physiology; D012098:Reproduction; D016868:Serratia Infections / Q000378:metabolism; D012706:Serratia marcescens / Q000502:physiology
D019476:Insect Proteins; C041137:storage proteins, Insecta