Preliminary investigation of the mechanisms of DDT and pyrethroid resistance in Culex quinquefasciatus Say (Diptera: Culicidae) from Saudi Arabia

1989 ◽  
Vol 79 (3) ◽  
pp. 361-366 ◽  
Author(s):  
A. M. Amin ◽  
J. Hemingway
Keyword(s):  
Saudi Arabia ◽  
Culex Quinquefasciatus ◽  
Glutathione Transferase ◽  
Pyrethroid Resistance ◽  
Preliminary Investigation ◽  
Oxidative Degradation ◽  
Cross Resistance ◽  
Transferase Activity ◽  
Metabolic Studies

AbstractHigh levels (>1000-fold) of resistance to DDT, permethrin and deltamethrin were detected in Culex quinquefasciatus Say from Saudi Arabia. Biochemical enzyme and metabolic studies indicated that there is evidence for a metabolic basis to both the organochlorine and pyrethroid resistances. Electrophysiological studies indicated that there is no kdr-type mechanism conferring resistance to the pyrethroid lambda-cyhalothrin neurophysiologically, although there is evidence of cross-resistance between DDT and the pyrethroids by bioassays. There was a change in the oxidase system in both the DDT- and permethrin-selected strains and an increase in glutathione transferase activity in the DDT-selected line. Metabolic studies indicated that both oxidases and glutathione transferases are involved with DDT resistance as DDA and DDE were the predominant metabolites after a 5-h in-vitro incubation period. Permethrin resistance is likely to involve an increase in oxidative degradation, but further metabolic studies are needed to confirm this.

scholarly journals New insecticide screening platforms indicate that Mitochondrial Complex I inhibitors are susceptible to cross-resistance by mosquito P450s that metabolise pyrethroids

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rosemary S. Lees ◽  
Hanafy M. Ismail ◽  
Rhiannon A. E. Logan ◽  
David Malone ◽  
Rachel Davies ◽  
...  
Keyword(s):  
Vector Control ◽  
Complex I ◽  
Pyrethroid Resistance ◽  
In Vitro Assays ◽  
Cross Resistance ◽  
Malaria Vector Control ◽  
Resistant Strains ◽  
Extended Exposure

Abstract Fenazaquin, pyridaben, tolfenpyrad and fenpyroximate are Complex I inhibitors offering a new mode of action for insecticidal malaria vector control. However, extended exposure to pyrethroid based products such as long-lasting insecticidal nets (LLINs) has created mosquito populations that are largely pyrethroid-resistant, often with elevated levels of P450s that can metabolise and neutralise diverse substrates. To assess cross-resistance liabilities of the Complex I inhibitors, we profiled their susceptibility to metabolism by P450s associated with pyrethroid resistance in Anopheles gambiae (CYPs 6M2, 6P3, 6P4, 6P5, 9J5, 9K1, 6Z2) and An. funestus (CYP6P9a). All compounds were highly susceptible. Transgenic An. gambiae overexpressing CYP6M2 or CYP6P3 showed reduced mortality when exposed to fenpyroximate and tolfenpyrad. Mortality from fenpyroximate was also reduced in pyrethroid-resistant strains of An. gambiae (VK7 2014 and Tiassalé 13) and An. funestus (FUMOZ-R). P450 inhibitor piperonyl butoxide (PBO) significantly enhanced the efficacy of fenpyroximate and tolfenpyrad, fully restoring mortality in fenpyroximate-exposed FUMOZ-R. Overall, results suggest that in vivo and in vitro assays are a useful guide in the development of new vector control products, and that the Complex I inhibitors tested are susceptible to metabolic cross-resistance and may lack efficacy in controlling pyrethroid resistant mosquitoes.

DDT resistance in Anopheles culicifacies Giles and A. subpictus Grassi (Diptera: Culicidae) from Sri Lanka: a field study on the mechanisms and changes in gene frequency after cessation of DDT spraying

1988 ◽  
Vol 78 (4) ◽  
pp. 717-723 ◽  
Author(s):  
P. R. J. Herath ◽  
K. G. I. Jayawardena ◽  
J. Hemingway ◽  
J. Harris
Keyword(s):  
Sri Lanka ◽  
Selection Pressure ◽  
Gene Frequency ◽  
Glutathione Transferase ◽  
Pyrethroid Resistance ◽  
Transferase Activity ◽  
Anopheles Culicifacies ◽  
Agricultural Use ◽  
Ddt Resistance ◽  
Susceptibility Tests

AbstractThe frequency of DDT resistance in Anopheles culicifacies Giles in Sri Lanka remained relatively constant from the cessation of DDT use for malaria control in 1975 until 1982. From 1983 to 1986, the frequency of resistance decreased slowly but significantly. In contrast, the resistance gene frequency in A. subpictus Grassi declined between 1980 and 1983, after which the trend was reversed, and there was a significant increase in DDT resistance in 1984–86. This rise in DDT resistance cannot be attributed to positive DDT selection pressure as there has been little or no agricultural use of DDT during this period. It is also unlikely that the rise in resistance is due to pyrethroid selection as the quantity of pyrethroids used on the island is low and there is no evidence of pyrethroid resistance from WHO susceptibility tests. Studies with the synergists FDMC (4-chloro-α-(4-chlorophenyl)-α-(trifluoromethyl)benzenemethanol) and piperonyl butoxide indicated the involvement of DDT-dehydrochlorinase rather than oxidase in the resistance. This was confirmed by metabolism studies, as DDT-resistant adults of both A. culicifacies and A. subpictus showed an increase in the rate of DDE production, which was also correlated with an increase in glutathione transferase activity.

scholarly journals Biochemical Characterization of the Interactions of the Novel Pleuromutilin Derivative Retapamulin with Bacterial Ribosomes

2006 ◽  
Vol 50 (11) ◽  
pp. 3875-3881 ◽  
Author(s):  
Kang Yan ◽  
Lenore Madden ◽  
Anthony E. Choudhry ◽  
Christine S. Voigt ◽  
Robert A. Copeland ◽  
...  
Keyword(s):  
Mode Of Action ◽  
Bacterial Infections ◽  
Biochemical Characterization ◽  
Multidrug Resistant ◽  
Cross Resistance ◽  
Transferase Activity ◽  
Bacterial Ribosome ◽  
Ribosomal P ◽  
Bacterial Skin Infections

ABSTRACT Retapamulin is a semisynthetic pleuromutilin derivative being developed as a topical antibiotic for treating bacterial infections of the skin. It is potent in vitro against susceptible and multidrug-resistant organisms commonly associated with bacterial skin infections. We report detailed mode of action studies demonstrating that retapamulin binds to the bacterial ribosome with high affinity, inhibits ribosomal peptidyl transferase activity, and partially inhibits the binding of the initiator tRNA substrate to the ribosomal P-site. Taken together, these data distinguish the mode of action of retapamulin from that of other classes of antibiotics. This unique mode of action may explain the lack of clinically relevant, target-specific cross-resistance of retapamulin with antibacterials in current use.

Susceptibility baselines for DDT metabolism and related enzyme systems in the sandfly Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae)

1989 ◽  
Vol 79 (4) ◽  
pp. 679-684 ◽  
Author(s):  
S. El-Sayed ◽  
J. Hemingway ◽  
R. P. Lane
Keyword(s):  
Culex Quinquefasciatus ◽  
Glutathione Transferase ◽  
Mosquito Species ◽  
Activity Level ◽  
Glutathione Transferases ◽  
Transferase Activity ◽  
Phlebotomus Papatasi ◽  
Difference Spectra ◽  
Enzyme Systems ◽  
Related Enzyme

AbstractDDT metabolism in Phlebotomus papatasi (Scopoli) was investigated and compared to that in DDT-resistant and susceptible strains of Culex quinquefasciatus Say and Anopheles gambiae Giles with the objective of establishing baselines for sandfly studies. P. papatasi produced eight metabolites of DDT, with DDE predominating, as in the two mosquito species. Both oxidases and glutathione transferases were found to be involved in DDT metabolism in insecticide-susceptible adults of P. papatasi. The activity level of glutathione transferases and the reduced and oxidized difference spectra of cytochrome P-450 were measured spectrophotometrically. The level of glutathione transferase activity in P. papatasi was lower than that in susceptible C. quinquefasciatus adults when expressed in terms of the activity per milligram of soluble protein but, in contrast, the cytochrome P-450 was slightly higher in both the reduced and oxidized states.

Modulation of Anopheles gambiae Epsilon glutathione transferase activity by plant natural products in vitro

2008 ◽  
Vol 23 (3) ◽  
pp. 391-399 ◽  
Author(s):  
Victor Muleya ◽  
Rose Hayeshi ◽  
Hilary Ranson ◽  
Berhanu Abegaz ◽  
Merha-Tibeb Bezabih ◽  
...  
Keyword(s):  
Natural Products ◽  
Anopheles Gambiae ◽  
Glutathione Transferase ◽  
Transferase Activity ◽  
Plant Natural Products

Reduction of S-nitrosoglutathione by alcohol dehydrogenase 3 is facilitated by substrate alcohols via direct cofactor recycling and leads to GSH-controlled formation of glutathione transferase inhibitors

2008 ◽  
Vol 413 (3) ◽  
pp. 493-504 ◽  
Author(s):  
Claudia A. Staab ◽  
Johan Ålander ◽  
Margareta Brandt ◽  
Johan Lengqvist ◽  
Ralf Morgenstern ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Glutathione Transferase ◽  
Cultured Cells ◽  
Hydrolysis Product ◽  
Indirect Evidence ◽  
Dual Function ◽  
Transferase Activity ◽  
Cofactor Recycling ◽  
Km Value

GSNO (S-nitrosoglutathione) is emerging as a key regulator in NO signalling as it is in equilibrium with S-nitrosated proteins. Accordingly, it is of great interest to investigate GSNO metabolism in terms of competitive pathways and redox state. The present study explored ADH3 (alcohol dehydrogenase 3) in its dual function as GSNOR (GSNO reductase) and glutathione-dependent formaldehyde dehydrogenase. The glutathione adduct of formaldehyde, HMGSH (S-hydroxymethylglutathione), was oxidized with a kcat/Km value approx. 10 times the kcat/Km value of GSNO reduction, as determined by fluorescence spectroscopy. HMGSH oxidation in vitro was greatly accelerated in the presence of GSNO, which was concurrently reduced under cofactor recycling. Hence, considering the high cytosolic NAD+/NADH ratio, formaldehyde probably triggers ADH3-mediated GSNO reduction by enzyme-bound cofactor recycling and might result in a decrease in cellular S-NO (S-nitrosothiol) content in vivo. Formaldehyde exposure affected S-NO content in cultured cells with a trend towards decreased levels at concentrations of 1–5 mM, in agreement with the proposed mechanism. Product formation after GSNO reduction to the intermediate semimercaptal responded to GSH/GSNO ratios; ratios up to 2-fold allowed the spontaneous rearrangement to glutathione sulfinamide, whereas 5-fold excess of GSH favoured the interception of the intermediate to form glutathione disulfide. The sulfinamide and its hydrolysis product, glutathione sulfinic acid, inhibited GST (glutathione transferase) activity. Taken together, the findings of the present study provide indirect evidence for formaldehyde as a physiological trigger of GSNO depletion and show that GSNO reduction can result in the formation of GST inhibitors, which, however, is prevented under normal cellular redox conditions.

scholarly journals Molecular Characterization of Prdx Family and Response of Antioxidant Enzymes in Berberine Hydrochloride-Treated Charybdis japonica Infected With Aeromonas hydrophila

2021 ◽  
Vol 8 ◽  
Author(s):  
Mingming Han ◽  
Tianheng Gao ◽  
Yuxin Liu ◽  
Zakaria Zuraini ◽  
Chenxi Zhu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Aeromonas Hydrophila ◽  
Glutathione Transferase ◽  
Control Group ◽  
Transferase Activity ◽  
Berberine Hydrochloride ◽  
Conserved Domain ◽  
Charybdis Japonica

Berberine hydrochloride is an isoquinoline alkaloid, which has antitumoral, antibacterial, and antiviral activities in vivo and in vitro. Charybdis japonica is one of the main economic species of crab in Southeast Asia. We studied the molecular mechanism of oxidative stress in berberine hydrochloride-treated C. japonica infected with Aeromonas hydrophila. C. japonica were infected with A. hydrophila after being submerged in different concentrations (0, 100, 200, and 300 mg/L) of berberine hydrochloride for 48 h. The full-length cDNA of Prx6 and the ORFs of Prx5 and PXL2A were cloned. Prx6 and PXL2A each have one conserved domain, Cys44, and Cys81. The Prx5 conserved domain contains three important Cys loci, Cys75, Cys100, and Cys76. Prx6 was different from Prx5 and PXL2A in the Peroxiredoxin family. The transcription levels of PXL2A infected with A. hydrophila were all higher than the control. The transcription levels of C. japonica were further increased by adding berberine hydrochloride and were increased the highest at a concentration of 300 mg/L. The activities of glutathione peroxidase, superoxide dismutase, and catalase in the hepatopancreas of berberine hydrochloride-treated C. japonica infected with A. hydrophila were significantly increased compared with those only infected with A. hydrophila and the control group. The glutathione transferase activity in the hepatopancreas was significantly increased in berberine hydrochloride-treated C. japonica. The results of this study provide a new understanding of the potential role of berberine hydrochloride on the oxidative stress mechanisms of C. japonica.

Novel CONCOMITANT mutations L932F and I936V in the Voltage-Gated Sodium Channel and Its Association With Pyrethroid Resistance in Culex quinquefasciatus (Diptera: Culicidae)

2020 ◽  
Author(s):  
Masaaki Sugiura ◽  
Fumiko Kimoto ◽  
Kentaro Itokawa ◽  
Shinji Kasai
Keyword(s):  
Cytochrome P450 ◽  
Sodium Channel ◽  
Culex Quinquefasciatus ◽  
Pyrethroid Resistance ◽  
Cross Resistance ◽  
Kdr Mutation ◽  
Voltage Gated Sodium Channel ◽  
Important Species ◽  
Voltage Gated ◽  
Brazilian Strain

Abstract Highly residual pyrethroids such as permethrin have been used for controlling mosquitoes that transmit infectious diseases. However, the selective pressure from such insecticides may result in cross-resistance against other pyrethroids used for household insecticides. In this study, we investigated the susceptibility of Culex quinquefasciatus Say collected from Brazil and Myanmar to permethrin in addition to four types of household pyrethroids. Both strains exhibited high resistance against all pyrethroids tested, indicating cross-resistance. Furthermore, we detected the knockdown resistance (kdr) mutations L932F+I936V in the voltage-gated sodium channel gene (VGSC) in the Brazilian strain. Notably, the L932F+I936V haplotype has previously been observed in in silico data, but it should be detected not directly from living insects. In comparison, a common kdr mutation, L1014F, was detected from the Myanmar strain. Although L1014F was also detected from the Brazilian strain, the allele frequency was too low to affect resistance. Both strains harbored the resistance-associated haplotypes of the cytochrome P450 gene, CYP9M10. The Brazilian strain demonstrated comparable resistance against pyrethroids as that of the Myanmar strain even when a cytochrome P450 inhibitor, piperonyl butoxide was added to the bioassay. Our results suggested that the L932F+I936V mutations confer the Brazilian strain of Cx. Quiquefasciatus with resistance at a comparable level to that conferred by the well-recognized kdr mutation L1014F in the Myanmar strain. The identification of unexplored mutations may improve the diagnosis and understanding of resistance of this medically important species.

scholarly journals Assessment the Changing Trend of Susceptibility to Two Insecticides Among Field-Population Culex quinquefasciatus Compared with the Same Population Undergoing to Multiple Colonization

2020 ◽  
Author(s):  
Atieh Shemshadian ◽  
Mohammad Reza Abai ◽  
Hassan Vatandoost ◽  
Navid DinparastDjadid ◽  
Mohammad Ali Oshaghi ◽  
...  
Keyword(s):  
Culex Quinquefasciatus ◽  
Pyrethroid Resistance ◽  
Rapid Development ◽  
Field Population ◽  
Cross Resistance ◽  
Pyrethroid Insecticides ◽  
Significant Difference ◽  
Changing Trend ◽  
Susceptibility Tests

Background: During the past decade, rapid development of insecticide resistance have been reported among many species of mosquito vectors against four main categories of insecticides worldwide. The aim of the research was to assess the variation trend of susceptibility levels of Culex quinquefasciatus to two insecticides separately for the field population compared with subsequent generations of the same sample after multiple colonization. Methods: Larvae and pupae of Cx. quinquefasciatus were collected from house sewages and reared to adult which blood-fed on roosters. Ten percent sucrose fed female mosquitoes aged 2–3 days were used for susceptibility tests with DDT and deltamethrin. Susceptibility levels was assessed in the adult stage of field stran Cx. quinquefasciatus against DDT 4.0% and deltamethrin 0.05% and continued up to next six generations undergoing multiple rearing at insectary condition. Results: The susceptibility levels to DDT 4.0% did not change compared to the field with the lab population to six generations. Regarding deltamethrin 0.05%, no significant difference was shown between field strain (58.3%) and 3 rd generation (52.7%) compared to the 6th one (33.8%). Conclusion: This finding may reflect the role of the kdr gene in resistance to organochlorine which has cross-resistance with pyrethroid insecticides. The results of this study clearly showed the irreversible trend of pyrethroid resistance among colonized mosquitoes. This is the first study of the resistance status of Cx. quinquefasciatus in Iran.

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