Journal of Medical Entomology (2007) 44, 238-248

Kathrin F.A. Langner, Karin E. Darpel, Eric Denison, Barbara S. Drolet, Wolfgang Leibold, Philip S. Mellor, Peter P.C. Mertens, Manfred Nimtz and Irene Greiser-Wilke (2007)
Collection and analysis of salivary proteins from the biting midge Culicoides nubeculosus (Diptera: Ceratopogonidae)
Journal of Medical Entomology 44 (2), 238-248
Abstract: Salivary proteins of hematophagous Culicoides spp. are thought to play an important role in pathogen transmission and skin hypersensitivity. Analysis of these proteins, however, has been problematic due to the difficulty in obtaining adequate amounts of secreted Culicoides saliva. In the current study, a collection method for midge saliva was developed. Over a 3-d period, 3- to 5-d-old male and female Culicoides nubeculosus Meigen (Diptera: Ceratopogonidae) were repeatedly placed onto the collection system and allowed to deposit saliva into a filter. Salivary products were eluted from the filters and evaluated by gel electrophoresis and mass spectrometry as well as by intradermal testing and determination of clotting time. Gel electrophoresis revealed ~ 55 protein spots displaying relative molecular masses from 5 to 67 kDa and isoelectric points ranging from 4.5 to 9.8. The majority of molecular species analyzed by mass spectrometry showed high convergence with salivary proteins recently obtained from a cDNA library of Culicoides sonorensis Wirth and Jones, including proteins involved in sugarmeal digestion, defense, and coagulation inhibition as well as members of the D7 family and unclassified salivary proteins. In addition, the proteome analysis revealed a number of peptides that were related to proteins from insect species other than Culicoides. Intradermal injection of the saliva in human skin produced edema, vasodilatation, and pruritus. The anticoagulant activity of the saliva was demonstrated by significantly prolonged clotting times for human platelets. The potential role of the identified salivary proteins in the transmission of pathogens and the induction of allergies is discussed.
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Database assignments for author(s): Philip S. Mellor

Research topic(s) for pests/diseases/weeds:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Culicoides nubeculosus