The Sphingomonas Plasmid pCAR3 Is Involved in Complete Mineralization of Carbazole
The Sphingomonas Plasmid pCAR3 Is Involved in Complete Mineralization of Carbazole
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DOI：
10.1128/jb.01486-06
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发表时间：
2006-12
影响因子：
3.2
通讯作者：
M. Shintani;Masaaki Urata;Kengo Inoue;Kaori Eto;H. Habe;T. Omori;H. Yamane;H. Nojiri
中科院分区：
文献类型：
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作者：
M. Shintani;Masaaki Urata;Kengo Inoue;Kaori Eto;H. Habe;T. Omori;H. Yamane;H. Nojiri
摘要我们测定了来自鞘氨醇单胞菌菌株KA 1的咔唑降解质粒pCAR 3的完整的254，797-bp核苷酸序列。参与复制和接合转移的约65 kb的区域显示与从芳香降解Novosphingobium aromaticivorans菌株F199分离的质粒pNL 1的区域相似。许多插入序列、转座子、重复序列及其残余物的存在表明该质粒在遗传结构上具有可塑性。虽然pCAR 3被认为携带用于接合转移的成簇基因，但KA 1和pCAR 3-治愈菌株（KA 1 W）之间的过滤器交配测定不成功，表明pCAR 3可能在接合转移中有缺陷。在pCAR 3上发现了几个降解基因，包括两种咔唑降解基因簇（car-I和car-II），以及咔唑初始加氧酶电子转移组分的基因（fdxI、fdrI和fdrII）。鉴定了邻氨基苯甲酸酯（和）、邻苯二酚（cat）、2-羟基戊-2，4-二烯酸酯（carDFE）、二苯并呋喃/芴（dbf/fln）、原儿茶酸酯（lig）和邻苯二甲酸酯（oph）降解的推定基因。似乎pCAR 3可能携带用于将咔唑降解为三羧酸循环中间体的成簇基因（car-I、car-II、fdxI、fdrI、fdrII和cat）; KA 1 W完全丧失了在咔唑上生长的能力，并且当KA 1在咔唑上生长时，上述咔唑降解基因均表达。逆转录-PCR分析还显示，car-I，car-II，和猫基因的转录诱导咔唑或其代谢中间体。用car-I、car-II、repA、帕拉、traI和traD基因制备的探针进行Southern杂交分析，结果表明几种鞘氨醇单胞菌咔唑降解菌具有与pCAR 3部分相似的DNA区域。
ABSTRACT We determined the complete 254,797-bp nucleotide sequence of the plasmid pCAR3, a carbazole-degradative plasmid from Sphingomonas sp. strain KA1. A region of about 65 kb involved in replication and conjugative transfer showed similarity to a region of plasmid pNL1 isolated from the aromatic-degrading Novosphingobium aromaticivorans strain F199. The presence of many insertion sequences, transposons, repeat sequences, and their remnants suggest plasticity of this plasmid in genetic structure. Although pCAR3 is thought to carry clustered genes for conjugative transfer, a filter-mating assay between KA1 and a pCAR3-cured strain (KA1W) was unsuccessful, indicating that pCAR3 might be deficient in conjugative transfer. Several degradative genes were found on pCAR3, including two kinds of carbazole-degradative gene clusters (car-I and car-II), and genes for electron transfer components of initial oxygenase for carbazole (fdxI, fdrI, and fdrII). Putative genes were identified for the degradation of anthranilate (and), catechol (cat), 2-hydroxypenta-2,4-dienoate (carDFE), dibenzofuran/fluorene (dbf/fln), protocatechuate (lig), and phthalate (oph). It appears that pCAR3 may carry clustered genes (car-I, car-II, fdxI, fdrI, fdrII, and, and cat) for the degradation of carbazole into tricarboxylic acid cycle intermediates; KA1W completely lost the ability to grow on carbazole, and the carbazole-degradative genes listed above were all expressed when KA1 was grown on carbazole. Reverse transcription-PCR analysis also revealed that the transcription of car-I, car-II, and cat genes was induced by carbazole or its metabolic intermediate. Southern hybridization analyses with probes prepared from car-I, car-II, repA, parA, traI, and traD genes indicated that several Sphingomonas carbazole degraders have DNA regions similar to parts of pCAR3.