Exploration of detoxification mechanisms of acaricide resistance in Ixodid ticks
| dc.contributor.advisor | Nirmal Sangwan | |
| dc.contributor.author | Surbhi | |
| dc.date.accessioned | 2020-02-06T10:13:53Z | |
| dc.date.available | 2020-02-06T10:13:53Z | |
| dc.date.issued | 2019 | |
| dc.description.abstract | To study the acaricide resistance status and possible mechanisms of action in conferring resistance to commonly used acaricides (Deltamethrin and Coumaphos), Hyalomma anatolicum and Rhipicephalus (Boophilus) microplus ticks were collected from gaushalas and commercial dairy farms of Hisar, Bhiwani and Charkhi Dadri districts of Haryana. Using standard AIT-DD against deltamethrin and coumaphos, higher degree of resistance was observed in H. anatolicum ticks against coumaphos as compared to deltamethrin whereas it varied in case of R. (B.) microplus against both the acaricides. H. anatolicum and R. (B.) microplus ticks larvae collected from Charkhi Dadri were found to be susceptible to both the acaricides used. Level I resistance was reported in 4 isolates collected from Shahpur, Dobhi, Mangali, Kaimri and level II in one isolate of Mingnikhera against coumaphos in H. anatolicum, whereas in R. (B.) microplus level I resistance was observed in 3 isolates collected from Dobhi, Kaimri and Mingnikhera. Kaimri isolates of both H. anatolicum and R. (B.) microplus ticks showed level I resistance against deltamethrin. H. anatolicum ticks having higher values of resistance factor (RF) against coumaphos were found to have higher α-esterase, β-esterase, gultathione-s-transferase (GST) and mono-oxygenase activities whereas the monoamine oxidase activities did not show any constant trend of either increase or decrease. With the increase in RF value against coumaphos in resistant isolates of R. (B.) microplus, the levels of enzyme activities increased. β-esterase activities were more prominent as compared to α-esterase in resistant H. anatolicum and R. (B.) microplus ticks. Development of resistance in R. (B.) microplus against coumaphos showed significant correlation with α-esterase, β-esterase, gultathione-s-transferase and mono-oxygenase activities whereas in H. anatolicum significant correlation only with GST was reported. Native PAGE analysis of esterases showed a total of 9 types numbered as EST-1h to EST-9h in H. anatolicum ticks whereas 6 types in R. (B.) microplus numbered as EST-1b to EST-6b irrespective of susceptible and resistant ones. When inhibition studies were undertaken, pCMB and CuSo4 (arylesterase inhibitor) didn’t inhibit the activities of enzymes indicating that arylesterases were not involved in the development of resistance against coumaphos in both the ticks. Further analysis of electrophoretogram showed that EST-6h and EST-8h in highly susceptible H. anatolicum ticks did not appear. However, these esterases were very prominent in resistant ticks and were found to be inhibited by PMSF (serine esterase inhibitor) indicating presence of serine residue at the enzyme’s active sites. EST-5b activity in R. (B.) microplus was observed only in resistant isolates collected from Dobhi, Kaimri and Mingnikhera and was found to be inhibited by eserine sulphate indicating development of resistance due to expression of acetylcholine esterase. The mechanism of resistance development in both the ticks against coumphos was different where in H. anatolicum it appeared due to more expression of EST-6h and EST-8h having serine residue at their active sites whereas in R. (B.) microplus due to more expression acetylcholineseterase. Organophosphate (carboxylesterase) and Pyrethroid (Domain II of sodium channel) genes were investigated partially for mutations in resistant isolates of H. anatolicum and R. (B.) microplus ticks and did not find any mutation in both the genes indicating possible mechanism for development of resistance was due to increased expression of detoxification enzymes as observed in the present study. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810142634 | |
| dc.keywords | Acaricide resistance, AIT-DD, LPT, Esterases, Monoxygenase, Glutathion-S-transferase, Monoamine oxidase, Carboxylesterase gene, Sodium channel gene, Hyalomma anatolicum, Rhipicephalus (Boophilus) microplus, Deltamethrin, Coumaphos | en_US |
| dc.language.iso | en | en_US |
| dc.publisher | LUVAS | en_US |
| dc.sub | Biochemistry | en_US |
| dc.subject | null | en_US |
| dc.theme | Exploration of detoxification mechanisms of acaricide resistance in Ixodid ticks | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | Exploration of detoxification mechanisms of acaricide resistance in Ixodid ticks | en_US |
| dc.type | Thesis | en_US |