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The potential role of Mycobacterium marinum mkl gene in bacterial resistance to the host immunity |
HUA Yi-Fei, WANG Qing-Lan, NIU Chen, GAO Qian |
Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Basic Medical Sciences, Fudan University, Shanghai 200032, China |
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Abstract A Mycobacterium marinum random mutant library using MycoMarT7 phage system was constructed. After screening, a mutant whose transposon insertion site was in MMAR_0994 (mkl) gene was obtained. The adult zebrafish were infected with the wild-type and the mutant strains respectively and the survival rates of the zebrafish were compared. The potential impact of the mutant on host innate immune system was tested by infecting the 48-hour post-fertilization zebrafish larvae using caudal vein injection. In vivo distribution of the bacteria was monitored by following green fluorescence in the larvae. The impact of the mutant on mouse macrophage cell line was tested. In addition, the acid tolerance level was also checked. The results showed that mkl mutant displayed attenuated virulence in the zebrafish infection model. The attenuated phenotypes in the zebrafish larvae and mouse macrophage cell line were observed. The invasion rates of the mutant and the wild-type were similar. The growth of the mutant was more sensitive to low pH. These results indicated that mkl may play a functional role in the interaction with host immune system.
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Received: 31 October 2014
Published: 25 June 2015
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Corresponding Authors:
GAO Qian, NIU Chen
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