Lei Chaoliang

EFFECTS OF CADMIUM ON HOUSEFLY: INFLUENCE ON GROWTH AND DEVELOPMENT AND METABOLISM DURING METAMORPHOSIS OF HOUSEFLY

Abstract The objective of this study was to elucidate the effects of cadmium on housefly, Musca domestica. It is suggested that of cadmium in low concentrations of had little influence on growth and development of housefly. Cadmium was mainly distributed in the digestive tracts of housefly larvae, where the cadmium content was higher than that of other parts. During the metamorphosis of housefly the change trend of the cadmium content was very apparent. The cadmium content increased gradually in larval period, whereas it decreased significantly after polarization. Until the sixth day after emergence, only negligible cadmium was left in adult housefly. All these results demonstrated that the response of housefly to cadmium is an evolution adaptation in natural selection.

STUDIES ON A CADMIUM‐INDUCED METALLOTHIONEIN IN HOUSEFLY LARVAE, MUSCA DOMESTICA

Abstract  The induction of metallothionein (MT) was studied in the housefly larvae (Musca domestica). Upon dietary exposure to Cd, two Cd‐binding proteins were isolated from the whole body homogenates, using gel filtration and ion exchange chromatography. Mass spectrometric measurement revealed that they have high purity and the molecular weight are 9045.9Da and 11560.2Da, respectively. Amino acid analysis showed that the content of cysteine is the highest, attaining to 18.2%. However, aromatic amino acid residues such as tyrosine (2.5%) and phenylalanine (3.1%) were also detected. In addition, MT from housefly larvae has strong heat stability. All these results suggest that the properties of MT isolated from housefly are very similar to that of mammalian MT, but some differences still exist.