Premium
Toxic impact of ingested Jatropherol‐I on selected enzymatic activities and the ultrastructure of midgut cells in silkworm, Bombyx mori L.
Author(s) -
Jing L.,
Fang Y.,
Ying X.,
Wenxing H.,
Meng X.,
Syed M. N.,
Fang C.
Publication year - 2005
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1111/j.1439-0418.2005.00939.x
Subject(s) - midgut , biology , endoplasmic reticulum , ingestion , bombyx mori , esterase , biochemistry , enzyme , medicine , botany , larva , gene
Jatropherol‐I, a phorbol‐type diterpene from Jatropha curcas seeds was found highly toxic to third instars silkworm larvae after ingestion with LC 50 values 0.5793, 0.2197 and 0.1578 mg/ml at 48, 72 and 120 h respectively. The acute toxicity was associated with changes in activities of several midgut enzymes and pathological changes in midgut epithelial cells. Jatropherol‐I caused various fluctuations in activities of different midgut enzymes in third instars larvae of silkworm. Compared with controls, both esterase and carboxyliesterase showed significantly depressed activities at 3 h ( t ‐test, P < 0.05) and increased activities at 24 h and rapidly decreased activities at 48 h after ingestion of 0.125 and 0.25 mg/ml of Jatropherol‐I. Jatropherol‐I induced two (E4 and E5) and depressed one (E2) of midgut esterase isozymes analysed 3 h after ingestion. There was no significantly different glutathione S‐transferase activity between most of treated silkworm and control ( t ‐test, P > 0.05). Activities of acetylcholinesterase fluctuated weakly in treated silkworm in 48 h. Jatropherol‐I induced a gradual decline in midgut protease activities in silkworm with an obvious dose‐ and time‐dependent effect. Jatropherol‐I also caused pathological changes in midgut cells, especially in their endoplasmic reticulum. They were noted slight dilatation on 12 h exposure, while extreme dilatation, vesiculations and shedding of ribosome from membrane were observed in endoplasmic reticulum after a longer time exposure. Other pathological changes in microvilli, lysosome, mitochondria and chromatin were also observed in midgut cell of treated silkworm.