The role of salivary nitrophorins in the ingestion of blood by the triatomine bug Rhodnius prolixus (Reduviidae: Triatominae).
To assist haematophagy, Rhodnius prolixus produces several bioactive molecules in its saliva which it injects into the host skin. The most abundant of these molecules are the nitrophorins (NPs). In this work, we reduced the expression of NP1-4 in the saliva of R. prolixus by RNAi and evaluated the subsequent feeding performance of the bugs using the cibarial pump electromyogram either on the dorsal skin or on the tail vein of the mice. NPs salivary mRNA was reduced by >99% in comparison to controls. Saliva from knockdown nymphs also presented 82% less haemproteins while the total protein was not reduced. Knockdown nymphs feeding on the skin had lower ingestion rates mainly due to the longer cumulative probing time and lower cibarial pump frequency. Another difference was that knockdown insects bit approximately 5 times more. No differences were observed between groups fed on the tail vein. When the feeding sites were compared, nymphs fed on the tail vein had higher effective ingestion rates. These findings endorse the importance of the NPs for the ability of bugs to complete the meal in a short total contact time with a low number of bites, decreasing the perception of the insect by the host.
Araujo
Ricardo N
RN
Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal Minas Gerais, Bloco I4, Sala 177, Av. Antônio Carlos 6627, Pampulha, CEP 30270-901 Belo Horizonte, MG, Brazil.
Soares
Adriana C
AC
Paim
Rafaela M M
RM
Gontijo
Nelder F
NF
Gontijo
Alberto F
AF
Lehane
Michael J
MJ
Pereira
Marcos H
MH
D000818:Animals; D001769:Blood / Q000469:parasitology; D014355:Chagas Disease / Q000469:parasitology; D004435:Eating; D006801:Humans; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D007303:Insect Vectors / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D051379:Mice; D009758:Nymph; D012239:Rhodnius / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D012463:Saliva / Q000737:chemistry / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000235:genetics / Q000378:metabolism*
D019476:Insect Proteins; D012471:Salivary Proteins and Peptides