Biochemical Foundations of Insecticide Resistance in Culex Mosquitoes from Minna, Nigeria: A Focus on Glutathione-S-Transferase and Protein Dynamics

The escalating challenge of insecticide resistance among mosquito populations presents a substantial obstacle to managing disease vectors across sub-Saharan Africa. This research delves into the biochemical foundations of this resistance in Culex mosquitoes collected from Minna, Nigeria, paying specific attention to shifts in protein levels and the activity of the detoxification enzyme glutathione-S-transferase (GST) after exposure to standard insecticides. Larvae gathered from the field were reared to adulthood and then subjected to standardized susceptibility tests using six different insecticides. We then used spectrophotometric techniques to compare the total protein concentration and GST enzyme activity between mosquitoes that survived the exposure (resistant) and those that died (susceptible). Our findings revealed that mosquitoes which survived insecticide exposure displayed a marked increase in GST activity, especially following contact with pyrethroid-based insecticides. Conversely, higher protein concentrations were consistently observed in the deceased mosquitoes, which may indicate that oxidative stress and associated protein damage are factors in their mortality. The pronounced rise in GST activity among the survivors strongly suggests that an enhanced capacity for detoxification is a critical mechanism enabling resistance in these Culex populations. This study underscores the value of biochemical markers in tracking resistance and offers crucial baseline information for guiding insecticide resistance management strategies in Nigeria. We recommend that ongoing surveillance of enzyme activity be incorporated into vector control initiatives to help design more effective interventions and prolong the usefulness of existing insecticides.