凹凸棒复合氯消毒剂消毒效果研究与安全性评价

目的:观察凹凸棒复合氯消毒剂的消毒效果和安全性。方法:将凹凸棒复合氯消毒剂和强力消毒灵按照不同的稀释度稀释后,与金黄色葡萄球菌、大肠杆菌、鼠伤寒沙门氏菌、蜡样芽孢杆菌、禽巴氏杆菌、丝状霉形体山羊亚种、鸡新城疫病毒、猪瘟病毒兔化弱毒分别作用不同时间,检测其抑菌、杀毒效果。通过急性毒性试验、皮肤刺激性试验和急性眼刺激试验评价该消毒剂的安全性。结果:凹凸棒复合氯消毒剂在不同稀释倍数下对细菌和病毒有一定的抑制和杀灭作用,且无明显毒性。结论:凹凸棒复合氯消毒剂对细菌和病毒有抑制和杀灭作用,且安全、有效。

Photoactivated Activities on Spodoptera litura Cell, Singlet Oxygen and Photostability of Photosensitizers

[Objective ]The aim of this study was to improve the photostability of pho-tosensitizers. [Method] 2,5-Diphenylthiophene and 2,5-dithienylethynylthiophene were synthesized by replacing thiophene rings of α-terthienyl （α-T） with benzene rings. Photoactivated activities on Spodoptera litura （SL） cells, singlet oxygen with UV and photostability of photosensitizers were investigated. [Result] The cytotoxicity of pho-tosensitizer 2,5-diphenylthiophene on SL cells was 0.22 and 0.16 μg/ml after treat-ment for 24 and 48 h, respectively, while that of 2,5-dithienylethynylthiophene on SL cells was 0.06 and 0.04 μg/ml. Singlet oxygen of 2,5-diphenylthiophene and 2,5-dithienylethynylthiophene was 1.047 5, 1.529 4 μg/mmol under UV, respectively. Degradation dynamic equations of 2,5-diphenylthiophene and 2,5-dithienylethynylthio-phene in methanol were Ct= 5.227 1e-0.006 1t, Ct= 5.084 2e-0.097 3t and half life was 111.79, 7.12 h. [Conclusion] Photosensitizer 2,5-diphenylthiophene has high singlet oxygen production ability, and high photoactivated cytotoxicity on SL cells under UV. Moreover, 2,5-diphenylthiophene has overcome the deficiency of photoactivated in-secticides, which is not applied directly in field because it degrades quickly in the environment.

Isolation and Characterization of a Dichlorvos-Degrading Strain DDV-1 of Ochrobactrum sp.

The objective of this research was to isolate a dichlorvos (2,2-dichlorovinyl dimethyl phosphate)-degrading strain of Ochrobactrum sp., and determine its effectiveness in remediation of a dichlorvos-contaminated soil. A dichlorvos-degrading bacterium (strain DDV-1) was successfully isolated and identified as an Ochrobactrumsp. based on its 16S rDNA sequence analysis. Strain DDV-1 was able to utilize dichlorvos as a sole carbon source, and the optimal pH and temperature for its cell growth and degradation were 7.0 and 30 ℃, respectively. Also, the growth and degradation of strain DDV-1 showed the same response to dissolved oxygen. In addition, the soil degradation test indicated that in soil spiked with 100 mg L-1 or 500 mg L-1 dichlorvos and inoculated with 0.5% or 1.0% (v/v) strain DDV-1, complete degradation of dichlorvos could be achieved in 24 h. The present study showed that strain DDV-1 was a fast dichlorvos-degrading bacterium in soil. However, further research will be needed to clarify the degradation pathway and the properties of the key enzymes involved in its biodegradation.

Toxicity of organophosphorus pesticide sumithion on larval stages of stinging catfish Heteropneustes fossilis

Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish Heteropneustes fossilis. Larvae were exposed to two concentrations(150 and 250 μg/L) of sumithion with one control in three replicates of each. Larvae samples were collected at 20- and 24-h intervals followed by observation under a digital microscope. Exposures of stinging catfish larvae to sumithion produced deformities including irregular head shape, lordosis, yolk sac edema, body arcuation, tissue ulceration, etc. The mortality rates of larvae were significantly increased in response to increase in sumithion concentrations. Furthermore, around 30% of the total adult stinging catfish reared in sumithiontreated aquaculture ponds were found to be deformed permanently. These findings highlight that exposure of stinging catfish to sumithion at the critical and sensitive stages in their life cycle may significantly reduce the number of returning adults. Therefore, the use of sumithion for crop protection needs to be considered carefully and alternatives to sumithion should to be developed for controlling aquatic insects in aqua-ponds during larval rearing.

Cell-specific expression of the diphtheria toxin A-chain coding sequence induces cancer cell suicide

OBJECTIVE: To test whether the diphtheria toxin A (DT-A) chain coding sequence linked to murine immunoglobulin Kappa light chain (IgKappa) promoter and enhancer have selective cytocidal effects on IgKappa producing cells. METHODS: The diphtheria toxin A gene or beta galactosidase (beta-gal) gene were linked to a murine IgKappa promoter and enhancer to construct pcDNA3IgKappaDTA or pcDNA3IgKappaLacZ plasmids. These plasmids were transfected into IgKappa producing or non-producing cells by the liposome coated DNA method. Expression of beta-gal activity and effects on cell growth of transfected cells were assessed. RESULTS: The beta-gal gene, under the control of cytomegalovirus (CMV) promoter, can express in all cell lines. Expression of beta-gal under the control of the IgKappa promoter was detected only in the IgKappa producing cell line, CA46. Expression of beta-gal was greatly suppressed when cotransfected with pcDNA3IgKappaDTA in CA46 cells.Cell growth of CA46 cells transfected with pcDNA3IgKappaDTA plasmid was significantly inhibited compared with CA46 cells transfected with pcDNA3IgKappaLacZ. CONCLUSION: Selective killing of IgKappa producing cells can be attained by introducing the diphtheria toxin A gene under the control of IgKappa promoter and enhancer.