ABSTRACT
OBJECTIVE: To study the effect of mosquito age on the pyrethroid resistance and P450 monooxygenase activity in Anopheles sinensis in Huainan City, Anhui Province, China, as well as the molecular mechanism of pyrethroid resistance. METHODS: Anopheles mosquito larvae were collected in fields, and were emerged to adults. Then the pyrethroid resistance and P450 monooxygenase activity of female mosquitoes were detected 1, 3, 6, 9, 12, 15 d and 20 d after emergence. Meanwhile, the resistance level and P450 monooxygenase activity of the sensitive mosquitoes in lab were detected as the control group. RESULTS: curves of pyrethroid resistance and P450 monooxygenase activity changes with the mosquito age presented unsymmetrically reversed "U" type. At 1 d after emergence, the resistance level and P450 monooxygenase activity were lower, and then they increased quickly. When 3-9 d after emergence, the resistance level and P450 monooxygenase activity rose to the highest level, and entered into plateau, then declined gradually. Compared to the sensitive mosquitoes in lab, the P450 monooxygenase activity of those in the field was higher at 3-12 d after emergence, but lower at 1 d after emergence, and at 15 and 20 d after emergence, they were almost equal to each other. CONCLUSION: The mosquito age is a confounding factor in the detection of resistance level and enzyme activity. The promotion of activity of P450 monooxygenase may be one of the reasons of the resistance. Using female adults with different ages in the field as study subjects may underestimate the real resistance level of mosquitoes, and mislead the use of insecticides.
Subject(s)
Anopheles/drug effects , Anopheles/enzymology , Culicidae/drug effects , Cytochrome P-450 Enzyme System/metabolism , Insect Proteins/metabolism , Pyrethrins/pharmacology , Animals , China , Culicidae/metabolism , Cytochrome P450 Family 6 , Female , Humans , Insecticide Resistance , Larva/drug effectsABSTRACT
The cellular and molecular pathways of fluoride toxicity in osteoblasts are not very well understood. Therefore, the objective of the present study was to evaluate the effects of sodium fluoride (NaF) on caprine osteoblasts cultured in vitro. Caprine osteoblasts at 2.0 x 10(-4) cells/ml were incubated in vitro with NaF at 0, 10(-8), 10(-7), 10(-6), 10(-5), 10(-4), 5.0 x 10(-4), and 10(-3) M, and then proliferation, differentiation, apoptosis, calcification, and alkaline phosphatase activity were examined. Also, the effect of NaF on osteoblastic cell viability and the molecular events leading to apoptosis were determined. Electron microscopy revealed cytoplasmic and nuclear alterations in the ultrastructure of osteoblasts exposed to various NaF concentrations. A cell-based quantitative evaluation of the MTT assay showed that NaF at concentrations of 10(-8) to 10(-5) M promoted cell proliferation, whereas at 10(-4) to 10(-3) M it suppressed cell proliferation and induced apoptosis. Alkaline phosphatase (ALP) activity and mineralization ability increased in cells treated at 10(-8) to 10(-5) M with sodium versus the controls, but decreased at 5.0 x 10(-4) to 10(-3) M dosage. The highest incidence of early apoptotic cells and late apoptotic cells was reached (3.33% and 2.92%, respectively) under NaF concentration of 10(-4) M. In conclusion, results of this study indicated that NaF modulates osteoblast proliferation and differentiation in a dose-dependent manner and modified osteoblast metabolism bidirectionally, suggesting NaF may play a significant role in osteoblast physiology.
