title: Vitellin- and hemoglobin-digesting enzymes in Rhipicephalus (Boophilus) microplus larvae and females.
abstract: The aim of the present study was to address the involvement of Rhipicephalus microplus larval cysteine endopeptidase (RmLCE) in protein digestion in R. microplus larvae and adult females. In this work, an improved purification protocol for native RmLCE was developed. Partial amino acid sequence of the purified enzyme indicates that it is the same enzyme as Boophilus microplus cathepsin-L1 (BmCL1). When vitellin (Vt) degradation by egg and larval enzymes was analyzed, stage-specific differences for RmLCE activity in comparison to vitellin-degrading cysteine endopeptidase (VTDCE) were observed. RmLCE is also able to degrade host hemoglobin (Hb). In agreement, an acidic cysteine endopeptidase activity was detected in larval gut. It was shown that cysteine and aspartic endopeptidases are involved in Vt and Hb digestion in R. microplus larvae and females. Interestingly, we observed that the aspartic endopeptidase Boophilus yolk cathepsin (BYC) is associated with a cysteine endopeptidase activity, in larvae. Synergic hemoglobin digestion by BYC and RmLCE was observed and indicates the presence of an Hb-degrading enzymatic cascade involving these enzymes. Our results suggest that RmLCE/BmCL1 has a continued role in vitellin and hemoglobin digestion during tick development.
authors: Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors: Andréia Bergamo
authors: AB
authors: Estrela
authors: Adriana
authors: A
authors: Seixas
authors: Vivian de Oliveira Nunes
authors: Vde O
authors: Teixeira
authors: Antônio Frederico Michel
authors: AF
authors: Pinto
authors: Carlos
authors: C
authors: Termignoni
mesh_terms: D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D002403:Cathepsins / Q000302:isolation & purification / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D007814:Larva / Q000201:enzymology; D010063:Ovum / Q000201:enzymology; D048494:Rhipicephalus / Q000201:enzymology* / Q000254:growth & development; D047048:Vitellins / Q000378:metabolism*
chemical_list: D006454:Hemoglobins; D047048:Vitellins; D002403:Cathepsins; D003546:Cysteine Endopeptidases; D016282:Aspartic Acid Endopeptidases