Enzymic sulphation of <i>p</i>-nitrophenol and steroids by larval gut tissues of the southern armyworm (<i>Prodenia eridania</i> Cramer)

The metabolic pathways of ingested ecdysteroids have been investigated in three insect species, the aphid Myzus persicae and two Lepidoptera, Plodia interpunctella and Ostrinia nubilalis. M. persicae produces mainly a 22-glucoside conjugate, whereas P. interpunctella eliminates a mixture of 20E and its 3-oxo and 3-epi derivatives, both in free form and as conjugates with various fatty acids. O. nubilalis only produces fatty acyl ester conjugates. These data point out the great diversity of detoxification mechanisms used by phytophagous insects in order to overcome the potential harmful effects of ecdysteroids present in their food.

Section: Diversity Of Detoxification Pathways Against Ingested Ecdystmentioning

confidence: 99%

Diversity of detoxification pathways of ingested ecdysteroids among phytophagous insects

Rharrabe

Alla²,

Maria

et al. 2007

“…These SULTs are cytosolic enzymes found in most body tissues, including the liver, intestine, brain, adrenal gland, and platelets (Blanchard, Freimuth, Buck, Weinshilboum, & Coughtrie, 2004; Glatt, 2000). In insects, the presence of SULTs has been suggested by sulfate conjugates of administered phenolic compounds (Yang & Wilkinson, 1972). For example, the armyworm ( Spodoptera frugiperda ) sulfotransferase SULT101A1 is involved in catalyzing retinol dehydration (Grun, Noy, Hammerling, & Buck, 1996).…”

Section: Introductionmentioning

confidence: 99%

Functional analysis of novel sulfotransferases in the silkworm Bombyx mori

Bairam

Kermasha

Liu

et al. 2020

Sulfoconjugation plays a vital role in the detoxification of xenobiotics and in the metabolism of endogenous compounds. In this study, we aimed to identify new members of the sulfotransferase (SULT) superfamily in the silkworm Bombyx mori. Based on amino acid sequence and phylogenetic analyses, two new enzymes, swSULT ST1 and swSULT ST2, were identified that appear to belong to a distinct group of SULTs including several other insect SULTs. We expressed, purified, and characterized recombinant SULTs. While swSULT ST1 sulfated xanthurenic acid and pentachlorophenol, swSULT ST2 exclusively utilized xanthurenic acid as a substrate. Based on these results, and those concerning the tissue distribution and substrate specificity toward pentachlorophenol analyses, we hypothesize that swSULT ST1 plays a role in the detoxification of xenobiotics, including insecticides, in the silkworm midgut and in the induction of gametogenesis in silkworm ovary and testis. Collectively, the data obtained herein contribute to a better understanding of SULT enzymatic functions in insects.

“…In other species, the gut played a role in ecdysteroid inactivation by sulphation (in the southern armyworm Prodeniu eriduniu [15]), or by epimerization of the hormones (in Munducu sextu [16], or Pieris brassicae [ln).…”

Section: Introductionmentioning

confidence: 99%

Possible inactivation of ingested ecdysteroids by conjugation with long‐chain fatty acids in the female tick Ornithodoros moubata (acarina:argasidae)

Connat

Diehl

Thompson

1986

Ornithodoros moubata females proved to be extremely sensitive to ingested 22,25‐dideoxyecdysone; 15‐20 ng provoked molting in all females and temporarily inhibited vitellogenesis. In contrast, this tick was very resistant to ingested ecdysteroids containing 22‐OH groups, such as ecdysone, 20‐hydroxyecdysone, ponasterone A, and makisterone A. Dosages about 500 times greater were necessary to produce supermolting and reduce fecundity [Connat et al: Z Ang Ent 96, 520 (1983)]. Ingested tritiated ecdysone, 20‐hydroxyecdysone, 2‐deoxyecdysone, and ponasterone A were rapidly converted to apolar esterase‐labile metabolites having approximately the same retention time as the AP2 identified as esters of ecdysteroids at C‐22 with long‐chain fatty acids (C16:0, C18:0, C18:1, C18:2) [Diehl et al: Int J Invert Reprod Dev 8, 1 (1985)]. These products were then gradually transformed to the more polar apolar conjugates, AP1. A more detailed study with ingestion of large quantities of 20‐hydroxyecdysone (10 μ/ml blood) demonstrated that only small amounts of free hormone were present in the hemolymph during the first day after the blood meal. The hormone was rapidly metabolized to AP2, then to AP1, in the intestinal cells and to a lesser extent in the peripheral tissues. Finally, AP1 accumulated in the intestinal cells and midgut content, probably because excretion outside the animal is impossible in this tick species. In contrast, ingested 22,25‐dideoxyecdysone was not metabolized to apolar products. This could account for its high biological activity. This compound was converted to unidentified more polar products. Two of them comigrated with ecdysone and 20‐hydroxyecdysone on RP‐18 HPLC column, but not on silica column, and therefore cannot correspond to these compounds. We hypothesize that esterification of ecdysteroids at the C‐22 position with fatty acids represents a detoxification mechanism for ingested ecdysteroids that might be present in blood from herbivorous or parasite‐infected hosts.