Modulation of the PGE2-Mediated Pathway in the Eclosion Blocking Effect of Flumethrin and Terpenoid Subfraction Isolated from Artemesia nilagirica in Rhipicephalus annulatus

Prostaglandins are a group of important cell-signaling molecules involved in the regulation of ovarian maturation, oocyte development, egg laying and associated behaviors in invertebrates. However, the presence of prostaglandin E2 (PGE2), the key enzymes for PGE2 biosynthesis and its interference by drugs were not investigated previously in the ovary of ticks. The present study was undertaken to assess the modulation of the PGE2-mediated pathway in the eclosion blocking effect of flumethrin and terpenoid subfraction isolated from Artemisia nilagirica in Rhipicephalus annulatus ticks. The acaricidal activities and chemical profiling of the terpenoid subfraction were performed. The localization of the cyclooxygenase1 (COX1) and prostaglandin E synthase (PGES) enzymes and the quantification of PGE2 in the ovaries of the ticks treated with methanol (control), flumethrin and terpenoid subfraction were also undertaken. In addition, the vitellogenin concentration in hemolymph was also assayed. Both flumethrin and the terpenoid subfraction of A. nilagirica elicited a concentration-dependent inhibition of fecundity and blocking of hatching of the eggs. The COX1 could not be detected in the ovaries of treated and control ticks, while there was no significant difference observed in the concentration of vitellogenin (Vg) in them. The presence of PGES in the oocytes of control ticks was confirmed while the immunoreactivities against PGES were absent in the vitellogenic oocytes of ticks treated with flumethrin and terpenoid subfraction. The levels of PGE2 were below the detection limit in the ovaries of the flumethrin-treated ticks, while it was significantly lower in the ovaries of the terpenoid subfraction-treated ticks. Hence, the prostaglandin E synthase and PGE2 were identified as very important mediators for the signaling pathway for ovarian maturation and oviposition in ticks. In addition, the key enzyme for prostaglandin biosynthesis, PGES and the receptors for PGE2 can be exploited as potential drug targets for tick control. The detection of PGES by immunohistochemistry and quantification of PGE2 by LC-MSMS can be employed as valuable tools for screening newer compounds for their eclosion blocking acaricidal effects.

Partial DnaK protein expression from Coxiella-like endosymbiont of Rhipicephalus annulatus tick

Q fever is one of the most important zoonotic diseases caused by the obligate intracellular bacteria, Coxiella burnetii. This bacterial infection has been frequently reported in both humans and animals, especially ruminants. Ticks are important ectoparasite and serve as reservoir hosts of Coxiella-like endosymbionts (CLEs). In this study, we have attempted to express chaperone-coding genes from CLEs of Rhipicephalus annulatus ticks collected fromcow path. The partial DnaK coding sequence has been amplified and expressed by Escherichia coli. Amino acid sequences have been analyzed by MS-MS spectrometry and the UniProt database. Despites nucleotide sequences indicating high nucleotide variation and diversity, many nucleotide substitutions are synonymous. In addition, amino acid substitutions compensate for the physicochemical properties of the original amino acids. Immune Epitope Database and Analysis Resource (IEDB-AR) was employed to indicate the antigenicity of the partial DnaK protein and predict the epitopes of B-and T-cells. Interestingly, some predicted HLA-A and B alleles of the MHC-I and HLA-DR alleles belonging to MHC-II were similar to T-cell responses to C. burnetii in Q fever patients. Therefore, the partial DnaK protein of CLE from R. annulatus could be considered a vaccine candidate and immunogenic marker with future prospects.

Synthesis of Nanocomposites Layered Double Hydroxide via Ocimum basilicum and Its Acaricidal Efficacy Against Multi-Resistance Rhipicephalus annulatus Tick

A layered double hydroxide (LDH) incorporated with Ocimum basilicum essential oil (OB) was prepared and its acaricide efficacy against Rhipicephalus annulatus tick was investigated. The OB essential oil was extracted from plants farmed in the study area. Zn–Al LDH/Gallate was prepared by co-precipitation method then OB oil was added to obtain OB/LDH nano-composite. The obtained product was characterized by X-Ray Diffraction (XRD), Fourier-transform infrared (FT-IR) and scanning electron microscopy (SEM). The acaricidal activity of different concentrations of the obtained OB/LDH nanocomposite (6.25, 12.5, 25, 50, 100, 200 and 300 l/mL) was evaluated via the adult immersion test (AIT), egg hatchability test (EHT), larval packet test (LPT) and repellency test. OB oil and OB/LDH nano-composite showed 100% adult mortality and prevent egg deposition at a dose of 300 l/mL. Also, eggs hatching was fully inhibited at 300 l/mL while at the concentration of 200 l/mL the inhibition rate was 95%. In LPT, OB/LDH showed a high toxicological effect which leading to 100% and 43% larval mortality at doses of 200 μ l/mL and 100 μl/mL, respectively. Meanwhile OB alone showed 100% and 45% larval mortality at doses of 300 μl/mL and 200 μl/mL, respectively. The LC50, LC90 and LC99 values of OB/LDH and OB were found to be 107.46 versus 209.908 μl/mL, 171.22 versus 282.63 μl/mL and 196.15 versus 298.26 μl/mL, respectively. The repellence activity was lasted for 3 h after application against larvae. OB/LDH was found to be more repellent than OB as evidenced by the RC50 values after 2 h and 3 h (48.82 vs. 79.99 μl/mL and 89.47 vs. 185.32μ l/mL, respectively). Overall, our results proved that LDH enhanced the larvaicidal and repellent efficacy of OB against R. annulatus tick larvae.

About location of Rhipicephalus annulatus (Say, 1821) (Acari, Ixodidae) ticks in the Kyzylorda region and their epizootological significance

Recently, there has been a change in the border of the ranges of ixodid ticks in the Kyzylorda region, respectively also the spread of various infections carried by them. The collected material on the fauna and distribution of ixodid ticks indicates an increase in the number of new species of ixodid ticks in this area. As a result of an epizootological survey of settlements in the southeastern part of the Kyzylorda region the Rhipicephalus annulatus ticks, carriers of pathogens of cattle pyroplamosis, were discovered for the first time in this region. As a result of an epizootological survey of settlements in the southeastern part of the Kyzylorda region in the fall of 2019 in two villages of the Zhanakorgan region, for the first time, several specimens of ticks were found on cattle, identified as Rhipicephalus annulatus - carriers of the pathogens of cattle pyroplamosis. In 2020, during repeated examinations of the same settlements, similar ticks were found at all stages of development. In the study by the method of enzyme-linked immunosorbent assay (ELISA) from ticks of this species, the antigen of the Crimea-Congo hemorrhagic fever virus was detected.