Araujo Ricardo N, Soares Adriana C, Paim Rafaela M M, Gontijo Nelder F, Gontijo Alberto F, Lehane Michael J, Pereira Marcos H
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.
Insect Biochem Mol Biol. 2009 Feb;39(2):83-9. doi: 10.1016/j.ibmb.2008.10.002. Epub 2008 Oct 18.
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.
为了辅助吸血，红带锥蝽在其唾液中产生几种生物活性分子，并将其注入宿主皮肤。这些分子中最丰富的是硝基亚铁血红蛋白（NPs）。在这项研究中，我们通过RNA干扰降低了红带锥蝽唾液中NP1 - 4的表达，并使用食窦泵肌电图评估了这些虫子随后在小鼠背部皮肤或尾静脉上的进食表现。与对照组相比，NPs唾液mRNA减少了>99%。来自基因敲除若虫的唾液中血蛋白也减少了82%，而总蛋白没有减少。以皮肤为食的基因敲除若虫摄取率较低，主要是由于累积探测时间较长和食窦泵频率较低。另一个差异是，基因敲除昆虫叮咬的次数大约多5倍。在尾静脉取食的组之间未观察到差异。当比较取食部位时，以尾静脉为食的若虫有效摄取率更高。这些发现证实了NPs对于虫子在短时间总接触和少量叮咬的情况下完成进食的能力的重要性，从而降低宿主对昆虫的感知。
