Morphology and protein profiles of salivary glands of filarial vector mosquito Mansonia uniformis; possible relation to blood feeding process

Background: Vector control is a key strategy for eradication of filariasis, but it is limited, possibly due to rapid propagation from global warming. In Thailand, Mansonia mosquitoes are major vectors of filariasis caused by Brugia malayi filarial nematodes. However, little is yet known about vector biology and host-parasite relationship.

Objectives: Demonstrate the preliminary data of salivary gland morphology and protein profile of human filarial mosquitoes M. uniformis.

Methods: Morphology of M. uniformis salivary gland in both sexes was comparatively studied under a light microscope. Total protein quantization and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to compare protein profile between male and female. In addition, quantitative analysis prior to and after blood feeding was made at different times (0, 12, 24, 36, 48, 60, and 72 hours).

Results: Total salivary gland protein of males and females was 0.32±0.03 and 1.38±0.02 μg/pair gland, respectively. SDS-PAGE analysis of the female salivary gland protein prior to blood meal demonstrated twelve bands of major proteins at 21, 22, 24, 26, 37, 39, 44, 53, 55, 61, 72, and 100 kDa. Compared to female, male salivary gland was composed of seven major protein bands at 39, 44, 53, 55, 61, 83, and 100 kDa. Quantitative study after blood feeding revealed that protein of 37 kDa decreased gradually whereas proteins of 61 and 83 kDa started to increase dramatically at 24 hours. It was postulated that the 37 kDa band, found only in the female, might serve as a candidate molecule for facilitating blood feeding.

Conclusion: Morphology and protein components of M. uniformis salivary glands might relate to blood feeding process and filarial disease transmission.