ABSTRACT
Objective@#To investigate the developmental toxicity of 2,4-dinitrochlorobenzene in zebrafish embryos.@*Methods@#AB wild-type male and female zebrafish were selected to mate and spawn, then the eggs were cultured with Holt buffer solution. Six dose groups ( 0.4, 0.8, 1.0, 1.2, 1.6, 2.0 μg/mL ), a solvent control group and a cosolvent control group, were set up with 20 embryos each. Malformations and death of embryos were observed at 48, 72 and 96 hpf ( hours post fertilization ), the mortality and 50% lethal concentration ( LC50 ) were also calculated. @*Results@#At 48, 72 and 96 hpf, the LC50 of 2,4-dinitrochlorobenzene on zebrafish embryos were 1.668, 1.043 and 0.895 μg/mL, respectively, with a downward trend. After 72 hpf, when the concentration reached 2.0 μg/mL, all the zebrafish died. In the range of 0.4-2.0 μg/mL, the mortality of zebrafish at 48, 72 and 96 hpf increased with the increase of 2,4-dinitrochlorobenzene concentration ( all P<0.05 ); the malformation rate of zebrafish embryos at 48 hpf increased with the increase of 2,4-dinitrochlorobenzene concentration ( P<0.05 ). Zebrafish embryos exposed to 2,4-dinitrochlorobenzene led to yolk sac edema, pericardial edema and spinal curvature. @*Conclusion@#2,4-dinitrochlorobenzene can affect the development of zebrafish embryos, which will lead to lethal and teratogenic effects.
ABSTRACT
The effect of the chitin synthesis inhibitor lufenuron on the various developmental stages of red flour beetle Tribolium castaneum was determined by exposing them to different sub-lethal concentrations (LC10, LC20 and LC40) of lufenuron through diet for 24 hrs. There was a dose dependent effect on the larval weight, time taken for pupation, and adult emergence, percentage pupation and percentage adult emergence. When two day old larvae were fed on sublethal concentrations through diet a small proportion of pupal –adult intermediates were observed at LC20 and LC40. Adults emerging from the larvae fed on diet containing LC10, LC20 and LC40 of lufenuron did not show any variation in the fecundity and hatchability of eggs from that of control. The fecundity of adults fed with sub-lethal concentration of lufenuron (obtained against two day old larvae through diet) was not affected, however, percentage hatching and survival was affected. Interestingly there was a reversal of the effect within ten days of treatment with respect to percentage hatching and survival. When eggs were exposed to treated diet hatching was not affected. The present data suggest that lufenuron even at sub-lethal concentrations has a very good larvicidal and ovicidal activity in T. castaneum.
ABSTRACT
The relation ship between lethal effects and the distribution of monocrotopho contents in the body of mice has been showed by using tracer determination of radioisotope. The authors also observed the difference of degree of inhibited cholinergic activity in blood and brain of mice to which monocrotopho was given orally in different lethal dose. The results showed that there was a close relatiom between the death of monocrotopho acute poison and toxicant contents in brain. At the same time, wealso found there was no significant difference between the degree of inhibited cholinergic activity in blood and brain of survival mice to which monocrotopho was given orally in LD_(50) and dead mice in same dose as well as in excess lethal dose. This paper deals with the toxicological mechanism of the death of monocrotopho poison.