Genome Mining and Expression Analysis of Carboxylesterase and Glutathione S-Transferase Genes Involved in Insecticide Resistance in Eggplant Shoot and Fruit Borer, Leucinodes orbonalis (Lepidoptera: Crambidae)

The shoot and fruit borer, Leucinodes orbonalis (Lepidoptera: Crambidae) is the major cause of low productivity in eggplant and insecticides being the mainstay of management of L. orbonalis. However, field control failures are widespread due to the evolution of insecticide resistance. Taking advantage of the whole genome sequence information, the present study investigated the level of insecticide resistance and the expression pattern of individual carboxylesterase (CE) and glutathione S-transferases (GSTs) genes in various field collected populations of L. orbonalis. Dose-mortality bioassays revealed a very high level of resistance development against fenvalerate (48.2–160-fold), phosalone (94-534.6-fold), emamectin benzoate (7.2–55-fold), thiodicarb (9.64–22.7-fold), flubendiamide (187.4–303.0-fold), and chlorantraniliprole (1.6–8.6-fold) in field populations as compared to laboratory-reared susceptible iso-female colony (Lo-S). Over-production of detoxification enzymes viz., CE and GST were evident upon enzyme assays. Mining of the draft genome of L. orbonalis yielded large number of genes potentially belonging to the CE and GST gene families with known history of insecticide resistance in other insects. Subsequent RT-qPCR studies on relative contribution of individual genes revealed over-expression of numerous GSTs and few CEs in field populations, indicating their possible involvement of metabolic enzymes in insecticide resistance. The genomic information will facilitate the development of novel resistance management strategies against this pest.

Markers for transfusion-transmissible infections in north Indian voluntary and replacement blood donors: prevalence and trends 1989-1996

BACKGROUND AND OBJECTIVES

Twenty five to 30% of multiple-transfusion recipients in India show evidence of infection with both HBV and non-A non-B hepatitis or HCV. To be licensed, blood banks must screen each donor unit for HBsAg, antibodies to HIV-1 and -2, and VDRL.

MATERIALS AND METHODS

Between 1989 and 1996, 132,093 voluntary and replacement donors at this centre were screened for the above markers, using commercially available kits. Some 19,531 donors were screened for HCV antibodies in 1995 and 1996 with an in-house EIA, using a synthetic peptide from core, NS3 and NS4 region proteins of all major HCV strains.

RESULTS

Data were tabulated annually. The proportion of voluntary donors increased from 15 to 32% during the eight years. HBsAg rates remained below 2.5%, antibodies to HIV increased from 0.04% to 0.55%, and VDRL reactivity increased from 0.23 to 0.52% between 1989 and 1995. Prevalence of all three infections showed a small but significant drop in 1996, and all three were significantly less frequent in voluntary donors. HCV antibodies were detected in 1.49% of donors tested. Donors with multiple infections were uncommon.

CONCLUSIONS

A change to voluntary blood transfusion service and addition of anti-HBc, anti-HCV, and possibly HIV antigen to the mandatory list for screening donor blood would reduce posttransfusion infections. Indigenous production of these assays would mitigate the financial burden, as has been the experience with the in-house HCV assay.