An insight into the sialome of Simulium guianense (DIPTERA:SIMulIIDAE), the main vector of River Blindness Disease in Brazil
1 Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, 12735 Twinbrook Parkway, National Institutes of Health, Rockville, Maryland 20892-8132, USA
2 Entomology Laboratory, Centro de Pesquisa René Rachou, Belo Horizonte, Minas Gerais, Brazil
BMC Genomics 2011, 12:612 doi:10.1186/1471-2164-12-612Published: 19 December 2011
Little is known about the composition and function of the saliva in black flies such as Simulium guianense, the main vector of river blindness disease in Brazil. The complex salivary potion of hematophagous arthropods counteracts their host's hemostasis, inflammation, and immunity.
Transcriptome analysis revealed ubiquitous salivary protein families--such as the Antigen-5, Yellow, Kunitz domain, and serine proteases--in the S. guianense sialotranscriptome. Insect-specific families were also found. About 63.4% of all secreted products revealed protein families found only in Simulium. Additionally, we found a novel peptide similar to kunitoxin with a structure distantly related to serine protease inhibitors. This study revealed a relative increase of transcripts of the SVEP protein family when compared with Simulium vittatum and S. nigrimanum sialotranscriptomes. We were able to extract coding sequences from 164 proteins associated with blood and sugar feeding, the majority of which were confirmed by proteome analysis.
Our results contribute to understanding the role of Simulium saliva in transmission of Onchocerca volvulus and evolution of salivary proteins in black flies. It also consists of a platform for mining novel anti-hemostatic compounds, vaccine candidates against filariasis, and immuno-epidemiologic markers of vector exposure.