Thomas J C, Berger F, Jacquier M, Bernillon D, Baud-Grasset F, Truffaut N, Normand P, Vogel T M, Simonet P
Laboratoire d'Ecologie Microbienne du Sol, UMR Centre National de la Recherche Scientifique 5557, Université Lyon I, Villeurbanne, France.
J Bacteriol. 1996 Oct;178(20):6049-55. doi: 10.1128/jb.178.20.6049-6055.1996.
The natural biotic capacity of soils to degrade gamma-hexachlorocyclohexane (gamma-HCH, lindane) was estimated using an enrichment technique based on the ability of soil bacteria to develop on synthetic media and degrade the xenobiotic compound, used as the sole source of carbon and energy. Bacterial inocula from relatively highly contaminated soils (from wood treatment factories) were found to promote efficiently the degradation of gamma-HCH, which subsequently permitted isolation of a competent gamma-HCH-degrading microorganism. The decrease of gamma-HCH concurrently with the release of chloride ions and the production of CO2 demonstrated the complete mineralization of gamma-HCH mediated by the isolate. This was confirmed by gas chromatography-mass spectrometry analyses showing that degradation subproducts of gamma-HCH included an unidentified tetrachlorinated compound and subsequently 1,2,4-trichlorobenzene and 2,5-dichlorophenol. The two linA- and linB-like genes coding, respectively, for a gamma-HCH dehydrochlorinase and a dehalogenase were characterized by using a PCR strategy based on sequence homologies with previously published sequences from Sphingomonas paucimobilis UT26. Nucleotide sequence analysis of the linA-like region revealed the presence of a 472-bp open reading frame exhibiting high homology with the linA gene from S. paucimobilis, while a preliminary study also indicated strong homology among the two linB genes. All enzymes involved in the gamma-HCH degradative pathway appear to be extracellular and encoded by genes located on the chromosome, although numerous cryptic plasmids have been detected.
利用一种富集技术来估计土壤降解γ-六氯环己烷（γ-HCH，林丹）的天然生物能力，该技术基于土壤细菌在合成培养基上生长并降解用作唯一碳源和能源的外源化合物的能力。发现来自污染程度相对较高的土壤（来自木材处理厂）的细菌接种物能有效促进γ-HCH的降解，随后从中分离出一种有降解能力的γ-HCH降解微生物。γ-HCH的减少与氯离子的释放和二氧化碳的产生同时发生，这表明该分离物介导了γ-HCH的完全矿化。气相色谱-质谱分析证实了这一点，分析表明γ-HCH的降解副产物包括一种未鉴定的四氯化化合物，随后是1,2,4-三氯苯和2,5-二氯苯酚。分别编码γ-HCH脱氯化氢酶和脱卤酶的两个类linA和类linB基因，通过基于与先前发表的少动鞘氨醇菌UT26序列同源性的PCR策略进行了表征。类linA区域的核苷酸序列分析显示存在一个472 bp的开放阅读框，与少动鞘氨醇菌的linA基因具有高度同源性，而初步研究也表明两个linB基因之间具有很强的同源性。尽管已检测到许多隐蔽质粒，但参与γ-HCH降解途径的所有酶似乎都是胞外的，且由位于染色体上的基因编码。
