Emelyanova Elena V, Ramanaiah Sudarsu V, Prisyazhnaya Nataliya V, Shumkova Ekaterina S, Plotnikova Elena G, Wu Yonghong, Solyanikova Inna P
G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Pushchino Center for Biological Research of the Russian Academy of Sciences, Prosp. Nauki 5, 142290 Pushchino, Russia.
Food and Biotechnology Research Lab., South Ural State University (SUSU), 76, Lenin Prospekt, 454080 Chelyabinsk, Russia.
Microorganisms. 2023 Jan 5;11(1):141. doi: 10.3390/microorganisms11010141.
Bacteria make a huge contribution to the purification of the environment from toxic stable pollutants of anthropogenic and natural origin due to the diversity of their enzyme systems. For example, the ability to decompose 3-chlorobenzoate (3CBA) by the four representative genera of Actinobacteria, such as , , , and , was studied. In most cases, the formation of 4-chlorocatechol as the only key intermediate during the decomposition of 3CBA was observed. However, strain 1CP was an exception, whose cells decomposed 3CBA via both 3-chloro- and 4-chlorocatechol. The enzyme 3-Chlorobenzoate 1,2-dioxygenase (3CBDO) induced during the growth of these bacteria in the presence of 3CBA differed significantly in substrate specificity from the benzoate dioxygenases induced upon growth in the presence of benzoate. The 6a strain was found to contain genes encoding chlorocatechol 1,2-dioxygenase, chloromuconate cycloisomerase, and dienelactone hydrolase, whose nucleotide sequence was 100% consistent with the sequences of the corresponding genes encoding the enzymes of the modified 4-chlorocatechol -cleavage pathway of the strain 1CP. However, the gene encoding chloromuconolactone dehalogenase () was not found in the representatives of the actinomycete genera, including and . A linear mega-plasmid carrying 3-chlorocatechol degradation genes remained stable after maintaining the 1CP strain on an agar-rich medium for 25 years. In general, a similar plasmid was absent in actinobacteria of other genera, as well as in closely related species of 6a.
由于细菌酶系统的多样性，它们对净化环境中人为和天然来源的有毒稳定污染物做出了巨大贡献。例如，研究了放线菌的四个代表性属（如[此处缺失具体属名]、[此处缺失具体属名]、[此处缺失具体属名]和[此处缺失具体属名]）分解3-氯苯甲酸（3CBA）的能力。在大多数情况下，观察到在3CBA分解过程中仅形成4-氯邻苯二酚作为唯一关键中间体。然而，1CP菌株是个例外，其细胞通过3-氯邻苯二酚和4-氯邻苯二酚两条途径分解3CBA。这些细菌在3CBA存在下生长期间诱导产生的3-氯苯甲酸1,2-双加氧酶（3CBDO）与在苯甲酸存在下生长时诱导产生的苯甲酸双加氧酶在底物特异性上有显著差异。发现6a菌株含有编码氯邻苯二酚1,2-双加氧酶、氯粘康酸环异构酶和二烯内酯水解酶的基因，其核苷酸序列与编码1CP菌株改良4-氯邻苯二酚裂解途径中相应酶的基因序列100%一致。然而，在包括[此处缺失具体属名]和[此处缺失具体属名]在内的放线菌属代表中未发现编码氯粘康醇内酯脱卤酶（[此处缺失具体酶名]）的基因。在富含琼脂的培养基上培养1CP菌株25年后，携带3-氯邻苯二酚降解基因的线性大质粒仍保持稳定。一般来说，其他属的放线菌以及6a的近缘物种中不存在类似质粒。
