Molecular characterization of Ribosomal DNA (ITS2) of hard ticks in Iran: understanding the conspecificity of Dermacentor marginatus and D. niveus.

OBJECTIVES: Hard ticks (Acari: Ixodidae) are ectoparasites of medical and veterinary importance. They are obligate blood-feeding vectors with the ability to transmit a wide variety of pathogens. Standard morphological keys are normally used for the identification of tick species. However, considering the importance of accurate species identification and the determination of bio-ecological characteristics of species, relying on morphological keys alone can be questionable. In this study, two DNA fragments (ITS2 and COI) were selected for phylogenetic evaluation of Iranian hard tick species belonging to the genera Dermacentor, Hyalomma, and Rhipicephalus. RESULTS: 1229 specimens of Dermacentor marginatus, D. niveus, Hyalomma anatolicum, Rhipicephalus bursa, and R. sanguineus s.l constituting 11 populations were collected from three different climatic and zoogeographical zones in Iran. Morphological studies revealed notable differences in important morphological characteristics between different populations of D. marginatus. The results of ITS2 sequence analysis provided additional evidence which supports the conspecificity of D. niveus and D. marginatus. Contrary to this finding, the sequence analysis of COI and phylogeny favored the separation of the two species. Given the greater importance of COI in identifying and discriminating species, a possibility heterospecificity between the two species should be considered.

Lectin Activity in Gut Extract of Culex pipiens.

BACKGROUND: The role of lectins is important in interaction between pathogens and mosquito vectors. This study was performed to identify agglutinin activities of protein molecules on the midgut of Culex pipiens. METHODS: Culex pipiens was reared in insectray condition and the midguts of males and females (blood fed and unfed) were dissected separately in Tris-HCl buffer. The extracts of midguts were applied for hemagglutinin assay against red blood cells of rabbit, mouse, rat, dog, horse, sheep, guinea pig, cow, human (A, B, AB, O groups). Then, the RBCs with relatively high agglutinin activity were chosen for carbohydrate inhibition assay. D (+) glucose, D (+) galactose, D (+) mannose, D (-) fructose, D (-) arabinose, L (-) fucose, lactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, sialic acid were used to specify carbohydrate binding lectin. RESULTS: The highest agglutinin activities were found against sheep and rabbits RBCs. Sexual diversity of agglutinin activities was observed among midgut extraction of males and females. In addition, variation in agglutinin activity of blood fed and unfed female mosquitoes were detected. The lectin activity was inhibited highly with glucose, galactose, fucose and fructose but less inhibitor activities was observed by arabinose, N-acetyl-D-galactosamine, n-acetyl-d-glucosamine, lactose and mannose. CONCLUSION: The secretion of hemagglutinins (lectins or lectin-like molecules) in the digestive system depends on the type of food in the gut. This suggests that emptying of the gut in preparation for protein rich food probably starts the secretion of hemagglutinins.