RESUMO
The objective of the study was to reveal physiological link between sex specific engorgement pattern and evading mechanism of ticks against oxidative stress as well as acaricides. Quantitative determination of nitric oxide radical scavenging, superoxide dismutase activity and reduced glutathione (GSH) concentrations in salivary gland and gut extracts of male and female Hyalomma anatolicum anatolicum (Acari: Ixodidae) ticks established significant variation in antioxidant responses between two sexes of the ticks. Higher activity of these antioxidants and GSH depletion in females clearly indicate stronger antioxidant defense in female ticks which is to combat host mediated oxidative assault during feeding for greater engorgement and reproductive stress. The females are also better equipped with the mechanism of acaricide resistance as evidenced by higher expression of esterases than males in unfed whole tick extracts in current study.
RESUMO
AIM: Ticks are obligate ectoparasites that have an impact on wide range of vertebrates and also act as a potential vector for the transmission of tropical theileriosis, babesiosis, etc., causing significant loss to livestock production worldwide. While feeding, they introduce their saliva containing different bioactive molecules into the host. These molecules have the capability to counteract the host hemostatic mechanism to suck host blood successfully. Therefore, the study was aimed to isolate anti-platelet aggregating peptides from salivary gland extract (SGE) of Hyalomma anatolicum ticks, a commonly available tick in India. MATERIALS AND METHODS: Female H. anatolicum salivary glands were dissected out and SGE was prepared by homogenizing it in a suitable buffer under ice. Extract so obtained was fractionated by gel filtration chromatography using Sephacryl S-200 column. Total protein concentration in fractions was estimated and bovine platelets were isolated, stimulated with thrombin (positive control), treated with Gly-Pro-Arg-Pro amide (negative control) and with salivary gland fractions for identification of proteins/peptides having anti-platelet aggregating activities. RESULTS: Proteins/peptides present in various salivary gland fractions inhibited the bovine platelet aggregation and the percent inhibition ranged between 33% and 35.8%. CONCLUSION: The results suggests that the fractions of H. anatolicum salivary glands possess thrombin-induced anti-platelet aggregating activity and which could be further exploited for raising anti-tick vaccine and also for therapeutic purpose.
RESUMO
AIM: Hyalomma anatolicum anatolicum ticks transmit Theileria annulata, causative agent of tropical theileriosis to cattle and buffaloes causing a major economic loss in terms of production and mortality in tropical countries. Ticks have evolved several immune evading strategies to circumvent hosts' rejection and achieve engorgement. Successful feeding of ticks relies on a pharmacy of chemicals located in their complex salivary glands and secreted saliva. These chemicals in saliva could inhibit host inflammatory responses through modulating cytokine secretion and detoxifying reactive oxygen species. Therefore, the present study was aimed to characterize anti-inflammatory peptides from salivary gland extract (SGE) of H. a. anatolicum ticks with a view that this information could be utilized in raising vaccines, designing synthetic peptides or peptidomimetics which can further be developed as novel therapeutics. MATERIALS AND METHODS: Salivary glands were dissected out from partially fed adult female H. a. anatolicum ticks and homogenized under the ice to prepare SGE. Gel filtration chromatography was performed using Sephadex G-50 column to fractionate the crude extract. Protein was estimated in each fraction and analyzed for identification of anti-inflammatory activity. Sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) was run for further characterization of protein in desired fractions. RESULTS: A novel 28 kDa protein was identified in H. a. anatolicum SGE with pronounced anti-inflammatory activity. CONCLUSION: Purification and partial characterization of H. a. anatolicum SGE by size-exclusion chromatography and SDS-PAGE depicted a 28 kDa protein with prominent anti-inflammatory activity.
RESUMO
To investigate and identify the ticks prevalent in the North East part of India, scanning electron microscope (SEM) and DNA sequence of nuclear second internal transcribed spacer (ITS2) and mitochondrial 16S ribosomal DNA (rDNA) were used. Based on the morphological and molecular analysis, the ticks infesting cattle of North East India were found to be Rhipicephalus (Boophilus) microplus and Haemaphysalis bispinosa. ITS2 and 16S rDNA sequence from R. (B.) microplus and H. bispinosa were amplified using universal and gene specific primers, sequenced and analysed. The length of the amplified ITS2 sequence of R. (B.) microplus and H. bispinosa, were found to be approximately 1,500 and 1,700 bp, respectively. The length of the 16S rDNA sequences in both the ticks was found to be similar in size, but they differ in their base pair constitutions. This is the first report of the nucleotide sequences of ITS2 and 16S rDNA of H. bispinosa. Phylogenetic analysis revealed that H. bispinosa is a close relative of H. longicornis. A polymerase chain reaction-restriction fragment length polymorphism diagnostic tool was developed based on HindIII digestion of ITS2 in order to facilitate the identification of these two species which cannot be distinguished once it is fully-fed. Present study describes the use of SEM and 16S rDNA/ITS2 based molecular analysis in identification and differentiation of fully fed tick species.
