1.Preliminary study on thiamethoxam degrading bacteria isolated from corn plantation
Sevakumaran Vigneswari ; Mohammad Hanif Sukarman ; Fazilah Ariffin
Malaysian Journal of Microbiology 2021;17(6):661-667
Aims:
Thiamethoxam (THIA) is a pesticide that has been widely used for its effectiveness in controlling and preventing insect pests. However, the use of THIA diffused in soil, surface and groundwater pose severe toxicity to the ecosystem. The hazardous pollution caused by the toxicity of THIA demands for remediation to ensure degradation of THIA into its safe constituent elements. Thus, the aim of this study is to isolate and identify potential THIA degraders for future bioremediation.
Methodology and results:
Bacteria were isolated from soil sample collected at a corn plantation which utilizes THIA as a source of pesticide. Overall, two bacterial isolates were isolated from the soil sample. The bacterial isolates were screened and identified for their ability to degrade pesticide by culturing in minimal salt media (MSM) supplemented with 50 mg/L THIA. The growth of isolates was observed and analyzed through spectrophotometry analysis, standard plate count method and pH value of culture medium. As a result, isolate THIA 1 had been found to possess the ability to degrade pesticide as it showed a high rate in growth of bacteria compared to its controls. Meanwhile, isolate THIA 2 showed no degrading activities while under treatment as it showed similar rate of growth towards its control. Isolate THIA 1 was identified as Acinetobacter sp. UMTFA THIA 1.
Conclusion, significance and impact of study
The isolation and identification of the pesticide degrading bacteria will provide promising source of pesticide degrading enzyme that can be further developed for enzymatic pesticide biodegradation. This will pave the way forward in bioremediation where new effective degradation tools can be developed for pesticide residue which otherwise lead to serious ecological problem.
Thiamethoxam
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Bacteria
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Corneal Transplantation
2.Occurrence regularity and integrated control of leaf miner in safflower.
Lan-Jie XU ; Hui-Zhen LIANG ; Zhan-Sheng NIE
China Journal of Chinese Materia Medica 2020;45(12):2835-2841
Leaf miner is one of the major pests on safflower, which causes yield loss and poor quality seriously. "Weihonghua", "nine safflower varieties" and "three chemical insecticides" as materials that used to evaluate variety and regularity of leaf miner, safflower resistant level, and different proportions insecticides in field efficiency test. The results showed that Liriomyza sativae and L. huidobrensis accounted for 80%, the peak period of two pests was all in July; but Phytomyza horticola is relative less, its peak period occured in June. Three were great difference of resistance to leaf miner among safflower varieties, FQ12 and YJ65 expressed higher resistibility to leaf miner by ratio method. With abamectin 2% emulsifiable concentrate diluted for 2 000 times, or the mixture three insecticides(bifenthrin 20% water emulsions, thiamethoxam 25% water dispersible granule, abamectin 2% emulsifiable concentrate=1∶1∶1) diluted for 3 000 times, which were sprayed on leaves at squaring stage and lethal rate was 96% after 48 h in the study. Through comparative study on the variety and regularity of leaf miner, screen for resistant varieties to leaf miner and for high efficiency pesticide. The study provides theoretical basis and reference for integrated pest management of leaf miner.
Animals
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Carthamus tinctorius
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Diptera
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Insecticides
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Pesticides
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Thiamethoxam
3.A case of acute poisoning with thiamethoxam.
Xiao Hua LOU ; Bing Wen ZHANG ; Xu Can MA
Chinese Journal of Industrial Hygiene and Occupational Diseases 2022;40(10):779-782
Thiamethoxam belongs to the second generation of neonicotinoid insecticides, and case of acute poisoning with thiamethoxam had never reported in China. This paper reviewed a case of oral poisoning with thiamethoxam pesticides, the patient suffered vomiting, generalized convulsions, confusion, and decreased oxygen saturation. After treated with gastric lavage, ventilator support, and the use of propofol, midazolam, sodium phenobarbital, and sodium valproate, the convulsions could not be controlled. Untill treated with penehyclidine hydrochloride and hemoperfusion combined with hemofiltration, the patient finally recovered and was discharged from the hospital. We suggest that the main treatments for acute severe thiamethoxam poisoning are decontamination and symptomatic support, pentoxifylline hydrochloride and hemoperfusion combined with hemofiltration may improve the patients' prognosis.
Humans
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Thiamethoxam
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Hemoperfusion
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Hemofiltration
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Prognosis
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Pesticides
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Insecticides
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Neonicotinoids
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Poisoning/therapy*