title: Antimicrobial activity in the tick Rhipicephalus (Boophilus) microplus eggs: Cellular localization and temporal expression of microplusin during oogenesis and embryogenesis.
abstract: Arthropods display different mechanisms to protect themselves against infections, among which antimicrobial peptides (AMPs) play an important role, acting directly against invader pathogens. We have detected several factors with inhibitory activity against Candida albicans and Micrococcus luteus on the surface and in homogenate of eggs of the tick Rhipicephalus (Boophilus) microplus. One of the anti-M. luteus factors of the egg homogenate was isolated to homogeneity. Analysis by electrospray mass spectrometry (ESI-MS) revealed that it corresponds to microplusin, an AMP previously isolated from the cell-free hemolymph of R. (B.) microplus. Reverse transcription (RT) quantitative polymerase chain reactions (qPCR) showed that the levels of microplusin mRNA gradually increase along ovary development, reaching an impressive highest value three days after the adult females have dropped from the calf and start oviposition. Interestingly, the level of microplusin mRNA is very low in recently laid eggs. An enhance of microplusin gene expression in eggs is observed only nine days after the onset of oviposition, achieving the highest level just before the larva hatching, when the level of expression decreases once again. Fluorescence microscopy analysis using an anti-microplusin serum revealed that microplusin is present among yolk granules of oocytes as well as in the connecting tube of ovaries. These results, together to our previous data, suggest that microplusin may be involved not only in protection of adult female hemocele, but also in protection of the female reproductive tract and embryos, what points this AMP as a considerable target for development of new methods to control R. (B.) microplus as well as the vector-borne pathogens.
authors.affiliation: Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Esteves
authors.forename: A C
authors.initials: AC
authors.lastname: Fogaça
authors.forename: R
authors.initials: R
authors.lastname: Maldonado
authors.forename: F D
authors.initials: FD
authors.lastname: Silva
authors.forename: P P A
authors.initials: PP
authors.lastname: Manso
authors.forename: M
authors.initials: M
authors.lastname: Pelajo-Machado
authors.forename: D
authors.initials: D
authors.lastname: Valle
authors.forename: S
authors.initials: S
authors.lastname: Daffre
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects*; D002177:Candidiasis / Q000276:immunology / Q000517:prevention & control; D002417:Cattle; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D016908:Gram-Positive Bacterial Infections / Q000276:immunology / Q000517:prevention & control; D006458:Hemolymph / Q000276:immunology; D007109:Immunity; D008826:Microbial Sensitivity Tests; D016982:Micrococcus luteus / Q000187:drug effects*; D008856:Microscopy, Fluorescence; D009866:Oogenesis; D010058:Oviposition; D010063:Ovum / Q000378:metabolism*; D048494:Rhipicephalus / Q000196:embryology / Q000276:immunology / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D023181:Antimicrobial Cationic Peptides; C542675:microplusin protein, Boophilus microplus