On wednesday, July 24,2024 miss Ngong Amy Futela defended with distinction her master dissertation at University of Buea, department of biochemistry and molecular biology.
Her study was placed under the theme : “ Allelic variation in glutathione-s-transferase epsilon 4(GSTe4) in pyrethroid resistance in Anopheles gambiae in Mangoum and Nkolondom, Cameroon”. Malaria is a deadly disease that continues to be a significant public health burden in many parts of the world. The increased resistance of major malaria vectors to pyrethroids (the main insecticide class used in LLINs) is threatening the efforts to control malaria by vector control. Hence, understanding the molecular bases of resistance, as well as the susceptibility status of a vector population is necessary to design and implement adapted resistance management strategies. Here, a genetic variant of GSTe4 was assessed in Anopheles gambiae in two agriculture intensive sites, Mangoum and Nkolondom to see its association with pyrethroid resistance. The expression profile of GSTe4 was also assessed by quantitative PCR (Polymerase chain reaction ) PCR (RT-qPCR).
Furthermore, the genetic diversity of this gene was assessed in both study sites by cloning, sequencing and analyzing the sequences. In silico prediction of the association of this genetic variant to resistance was conducted by modelling the structure of the protein and assessing its binding distance with that of the known susceptible protein in Kisumu. An allele specific PCR was run on deltamethrin exposed Mangoum _Kisumu hybrids, F3 generation DNA (Deoxyribonucleic Acid ) samples alive and dead to assess the impact of the mutation in vivo. The expression level of this gene was not significantly different from that of the susceptible strain, Kisumu. From sequence analysis, GSTe4 was highly polymorphic in both study sites. In silico prediction revealed that there is no significant difference between the Kisumu and Mangoum protein’s ability to metabolize pyrethroids. The allele specific PCR also showed that there is no significant difference in frequencies between homozygous resistant (RR) and homozygous susceptible (SS) genotypes in the alive and dead samples. Overall, these results show that the allelic variation in GSTe4 is not associated to deltamethrin resistance.
