产低温超氧化物歧化酶南极菌株的筛选、鉴定及其部分酶学性质

SCREENING AND CLASSIFICATION FOR LOW-TEMPERATURE SUPEROXIDE DISMUTASE-PRODUCING ANTARCTIC BACTERIA AND CHARACTERISTICS OF THE SUPEROXIDE DISMUTASES

从421株南极细菌中筛选出产超氧化物歧化酶南极细菌NJ062、NJ379、NJ522和NJ548。它们的最适生长温度在10—15℃之间,在0℃均能生长,属于嗜冷菌。4株南极嗜冷菌均含有一种类型的SOD同工酶。菌株NJ062的超氧化物歧化酶为Mn-SOD;菌株NJ379,NJ522和NJ548的超氧化物歧化酶均为Fe-SOD。它们所产的超氧化物歧化酶最适酶活温度大约在40—50℃,在0℃仍有较高的活性,为最高活性的20%—35%,热稳定性较差,属低温酶。通过16S rDNA序列对4株产低温超氧化物歧化酶的南极嗜冷菌NJ062、NJ379、NJ522和NJ548进行鉴定。结果表明,它们均属于细菌域(Bacteria)中的紫细菌类群(Proteobacteria)中的γ-亚群。其中菌株NJ062属于假交替单胞菌属(Pseudoalteromonassp.);NJ379属于希瓦氏菌属(Shewanellasp.);NJ522和NJ548属于海单胞菌属(Marinomonassp.)。

Four SOD-producting bacteria NJ062, NJ379, NJ522 and NJ548 were selected from 421 Antarctic bacteria. They belonged to psychrophile for their optimum growth temperatures were about 10-15℃ and they could grow at 0 ℃ and they only contained one kind of SOD isoenzymes. The SOD of NJ062 was Mn-SOD, while the SODs of other three bacteria were FeSOD. The four SOD＇ s activity at 0 ℃ was nearly 20%-35% of the maximum activity, and their maximal activity temperature was 40-50 ℃. In addition, the four SODs were unstable to higher temperature indicating that they were cold-active enzymes. Four Antarctic psychrophile NJ062, NJ379, NJ522 and NJ548 were identified by 16S rDNA sequence analysis and result showed that all of these four strains belonged to γ-Proteobacteria in Bacteria. The strain N J062 was determined as genus Pseudoalteromonas sp. , the strain NJ379 belonged to genus Shewanella sp. , and the strain NJ522 and NJ548 were classified as Marinomonas sp..