A rod-shaped, Gram-negative chlorpyrifos-methyl (CM) degrading bacterium (designated strain KR200) was isolated from a Korean rice paddy soil and was further tested for its substrate specificity against 11 insecticides and its sensitivity against eight commercial antibiotics. Based on morphological, biochemical, and molecular characteristics, this bacterium showed greatest similarity to members of the order Flavobacteriales and was shown to be most closely related to members of the Chryseobacterium proteolyticum group. Strain KR200 hydrolyzed CM to 3,5,6-trichloro-2-pyridinol (TCP) but could not degrade TCP further. The isolate was also able to degrade chlorpyrifos, dicrotophpos, monocrotophos, and carbaryl at 300 μg mL–1 but diazinon, dimethoate, and furathiocarb at 100μg mL–1. The ability to degrade CM was found to be encoded on the chromosome. Genes encoding resistance to amphotericin B, polymixin B sulfate, and tetracycline were also located on the chromosome. This bacterium merits further study as a potential biological agent for the remediation of soil, water, or crop contaminated with organophosphorus (OP) compounds because of its greater biodegradation activity and its broad specificity against a range of OP insecticides.

The Organophosphorus pesticides are widely used for agricultural and domestic purposes due to their relatively low persistence in the environment. Chlorpyrifos-methyl (CM) is used at a rate of over 14 million pounds per year in US agriculture, ranking it as the second most heavily used pesticide. This study aimed at isolating bacteria from soil and determining their ability to degrade CM and identify the intermediates in culture broth. Bacteria capable of degrading CM was isolated by enrichment culture. Chryseobacterium sp. strain KR200 degraded CM up to 91.58% in 7days. Studies with CM in liquid culture of Chryseobacterium sp. strain KR200 demonstrated that the isolate hydrolyzed CM to 3,5,6-trichloro-2-pyridinol, and utilized this compound for growth and energy. We performed SDS-PAGE and two-dimensional gel electrophoresis and identified proteins whose expression pattern is affected by CM using mass spectrometry. The results revealed various proteins that can be grouped according to their respective cellular function. These results highlight the potential of this bacterium to be used in the clean up of contaminated pesticide waste in the environment.

파밤나방(Spodoptera exigua(Hubner))에 미치는 chlorpyrifos-methyl(COM)의 화학적 불임효과를 미량국부처리법으로 조사하였다. 아치사량의 CPM이 5령충에 처리됐고 이로부터 형성된 성충의 산란수와 부화율이 분석되었다. CPM이 처리된 암수의 동계교배 집단에선 충체별 100 처리집단을 제외하고 처리농도의 차이에 따라 산란수의 차이를 보이지 않았다. 그러나 부화율은 CPM 처리농도에 따라 CPM 처리 집단이 무처리 동계교배 집단에 비해 뚜렸하게 낮았다. 무처리 암수와 CPM(100/충체)으로 처리된 암수를 상호교배한 두 집단들은 암수 모두 CPM으로 처리된 집단과 같은 낮은 산란수 및 부화율을 보였다. 이는 CPM이 우성치사인자의 화학불임제로서 작용했음을 나타냈다. 또 CPM이 이 해충의 유전방제법을 개발하는데 이용될 수 있음을 시사한다.