[Effect of alpha-terthienyl on protein, esterase and lipid peroxidation of Aedes albopictus larvae]

To study the effect of alpha-terthienyl (alpha-T) on protein, esterase and lipid peroxidation of Aedes albopictus larvae.

Sensitive and resistant strains of Aedes albopictus stage IV larvae were used. Bradford method was used to detect protein content. The breeding fluid of experiment group contained alpha-T (5.34 microg/L), and control group contained only acetone (3.95 microg/L). Histochemistry method was used to detect esterase activity. Larvae in the experiment group were cultured in fluid containing alpha-T (6.24 microg/L) but no alpha-T in the control group. TBA method was used to detect malondialdehyde (MDA). Larvae of the sensitive strain were divided into 5 sub-groups: A - acetone control (containing acetone 3.95 microg/L), B - ultra-violet irradiation (UV) control (same with A but treated by UV), C, D, E - experiment groups with alpha-T (4.58, 5.34 and 6.24 microg/L respectively). All groups were kept in dark condition for 1 hour, followed by UV for 1 hour (except group A), then fed under normal condition.

With UV and alpha-T, the protein content of experiment group (1.225 mg/ml) was higher than that of control (1.120 mg/ml) (P<0.05) in sensitive strain; that of experiment group (1.199 mg/ml) was higher than that of control (1.114 mg/ml) (P<0.05) in the resistant strain. After 2, 4, 6, and 8 hour treated by both alpha-T and UV, the esterase activity all decreased in experiment group, and reached to the lowest 8 hours later (P<0.05). MDA contents was 2.286 nmol/mg protein in acetone control group and 2.322 nmol/mg protein in UV control, but 3.156, 4.188 and 4.684 nmol/mg protein respectively in the 3 experiment groups after treated by alpha-T and UV. The higher dose of alpha-T, the higher content of MDA (P<0.05).

Under UV, alpha-T can increase the protein and MDA content of the larvae of Ae. albopictus but decrease the esterase activity.