The neuropeptidome of Rhodnius prolixus brain.

We show a sensitive and straightforward off-line nano-LC-MALDI-MS/MS workflow that allowed the first comprehensive neuropeptidomic analysis of an insect disease vector. This approach was applied to identify neuropeptides in the brain of Rhodnius prolixus, a vector of Chagas disease. This work will contribute to the annotation of genes in the ongoing R. prolixus genome sequence project. Peptides were identified by de novo sequencing and comparisons to known neuropeptides from different organisms by database search. By these means, we were able to identify 42 novel neuropeptides from R. prolixus. The peptides were classified as extended FMRF-amide-related peptides, sulfakinins, myosuppressins, short neuropeptide F, long neuropeptide F, SIF-amide-related peptides, tachykinins, orcokinins, allatostatins, allatotropins, calcitonin-like diuretic hormones, corazonin, and pyrokinin. Some of them were detected in multiple isoforms and/or truncated fragments. Interestingly, some of the R. prolixus peptides, as myosuppressin and sulfakinins, are unique in their characteristic C-terminal domain among insect neuropeptides identified so far.