Karani Manisha, Shashidhar Ravindranath, Kakatkar Aarti, Gautam Raj Kamal, Sukhi Shibani, Pansare-Godambe Lipika, Bandekar Jayant
Food Technology Division, Bhabha Atomic Research Centre, Tormbay, Mumbai 400 085, India.
Can J Microbiol. 2015 Jan;61(1):89-92. doi: 10.1139/cjm-2014-0636.
A radiation-resistant bacterial isolate from gamma-radiation-processed (5 kGy) semidried prawns was identified as a new strain of Macrococcus caseolyticus and was designated as M. caseolyticus (A) on the basis of morphological and biochemical characterization and 16S rRNA sequencing. DNA-DNA hybridization studies with M. caseolyticus DSM 20597(T) further confirmed the isolate as M. caseolyticus. Major fatty acids present in M. caseolyticus (A) were C14:0, C16:1ω11c, and C18:1ω9c, whereas C15:0anteiso, C16:0iso, and C18:0iso were absent. The closest match for the isolate, as per fatty acid methyl ester analysis, was M. caseolyticus DSM 20597(T). However, the similarity index was significantly low (0.112), which indicates that the isolate could be a new strain of M. caseolyticus. The decimal reduction dose (D10) for M. caseolyticus (A), M. caseolyticus JCSC5402, and Staphylococcus aureus MTCC96 was 1.18, 0.607, and 0.19 kGy, respectively. This is the first report on radiation resistance of M. caseolyticus. Macrococcus caseolyticus (A) is more resistant to gamma and UV radiation stress than are M. caseolyticus JCSC5402 and S. aureus MTCC96; however, it is sensitive to heat as well as desiccation stress.
从经γ射线处理（5千戈瑞）的半干对虾中分离出的一株抗辐射细菌被鉴定为溶酪大球菌的一个新菌株，并根据形态学、生化特征及16S rRNA测序将其命名为溶酪大球菌（A）。与溶酪大球菌DSM 20597(T)进行的DNA-DNA杂交研究进一步证实该分离株为溶酪大球菌。溶酪大球菌（A）中存在的主要脂肪酸为C14:0、C16:1ω11c和C18:1ω9c，而不存在C15:0anteiso、C16:0iso和C18:0iso。根据脂肪酸甲酯分析，该分离株与溶酪大球菌DSM 20597(T)的匹配度最高。然而，相似性指数显著较低（0.112），这表明该分离株可能是溶酪大球菌的一个新菌株。溶酪大球菌（A）、溶酪大球菌JCSC5402和金黄色葡萄球菌MTCC96的D10值分别为1.18、0.607和0.19千戈瑞。这是关于溶酪大球菌抗辐射性的首次报道。溶酪大球菌（A）比溶酪大球菌JCSC5402和金黄色葡萄球菌MTCC96对γ射线和紫外线辐射应激更具抗性；然而，它对热以及干燥应激敏感。
