Reducing the expression of glutathione transferase D mRNA in Drosophila melanogaster exposed to phenol and aniline

Abstract

Phenol and aniline are toxic to animals. The purpose of the present study was to examine the expression of glutathione transferase D mRNA in fruit flies altered by long-term exposure to phenol and aniline. Changes in the amount of mRNA were measured by a semiquantitative reverse-transcription polymerase chain reaction assay. The level of each glutathione transferase D mRNA expressed in the phenol-treated and aniline-treated strains of adult fruit flies differed after chemical treatment. Aniline was more potent than phenol in suppressing the expression of cytosolic glutathione transferase D mRNA. Aniline reduced the level of glutathione transferase mRNA expressed in the aniline-treated strain to less than a 0.5 fraction as compared to that measured in the wild-type strain. But phenol was only able to suppress the GstD7 and GstD4 mRNAs expressed in the phenol-treated strain. Neither aniline nor phenol reduced the expression of microsomal glutathione transferase mRNA in fruit flies.

Interactions between detoxification mechanisms and excretion in Malpighian tubules ofDrosophila melanogaster

“…Specific genes encoding P450 and GST enzymes (Table1) were chosen, therefore, based on their enrichment in Malpighian tubules as specified in FlyAtlas (Chintapalli et al, 2007) and by Yang et al (Yang et al, 2007), and also on the basis of changes in their expression in adult Drosophila after PBO treatment (Willoughby et al, 2007) or exposure to dietary phenol (Ding et al, 2005).…”

“…Willoughby et al, 2007), whereas dietary PBO is associated with decreases in expression of GstD1 and GstD5 in the tubules and a 1.5-fold increase in GstE1. It is important to exercise caution in inferring changes in enzymatic actvity of GSTs in the tubules because whole-fly studies indicate that phenol exposure may result in increases in GST enzymatic activity but no change in the levels of mRNA for GstD1, GstD5, GstD8 and GstE1 and a reduction in the levels of mRNA for GstD4 and GstD7 (Shen et al, 2003;Ding et al, 2005). Our functional studies also showed that MTX secretion more than doubled in tubules of flies reared on the phenol-enriched diet for seven to 10 generations relative to controls.…”

“…The Cyp genes Cyp6a2, Cyp6a8 and Cyp12d1, which are most strongly induced by PBO in adult male Drosophila, are also among the 12 Cyp genes associated with insecticide resistance (Willoughby et al, 2007;Giraudo et al, 2010). Previous studies have also shown that rearing Drosophila for multiple generations on diets containing 0.3% phenol is associated with an increase in GST enzymatic activity but with no change in the levels of mRNA for GstD1, GstD5, GstD8 and GstE1 and with a reduction in the levels for GstD4 and GstD7 (Shen et al, 2003;Ding et al, 2005).…”