Kumar Vijay, Tiwari Santosh Kumar
Department of Genetics, Maharshi Dayanand University, Rohtak, 124001, Haryana, India.
Extremophiles. 2017 May;21(3):609-621. doi: 10.1007/s00792-017-0930-6. Epub 2017 Apr 4.
Haloferax larsenii HA3 was able to grow optimally in HS medium containing 15% NaCl, at pH 7.2 and 42 °C in aerobic conditions. Strain HA3 was found to be round shape, Gram-negative, catalase-positive, sensitive to bile acid, and resistant to chloramphenicol, and could not utilize arginine. The lipid profile revealed the presence of glycerol diether moiety (GDEM) suggesting Haloarchaea characteristics. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that it was closely related to H. larsenii ZJ206. Interestingly, strain HA3 was found to produce halocin HA3 which was purified using ultrafiltration and chromatography. It was found to be stable up to 80 °C, pH 2.0-10.0, organic solvents, surfactants, and detergents tested. However, the activity of halocin HA3 was completely reduced in the presence of proteinase K and trypsin. It was found to be halocidal against H. larsenii HA10, rupturing cell boundary and leading to cell death. The molecular weight of halocin HA3 was found to be ~13 kDa and MALDI-TOF MS/MS analysis suggested no homology with known halocins. The N-terminal ten amino-acid residues, NHMNLGIILETN-COOH, suggested a new/novel halocin. These properties of halocin HA3 may be applicable for control of Haloarchaea in environments and salted foods.
拉氏嗜盐古菌HA3能够在含有15%氯化钠的HS培养基中，于pH 7.2、42°C的有氧条件下最佳生长。发现菌株HA3呈圆形，革兰氏阴性，过氧化氢酶阳性，对胆汁酸敏感，对氯霉素耐药，且不能利用精氨酸。脂质谱显示存在甘油二醚部分（GDEM），表明具有嗜盐古菌特征。基于16S rRNA基因序列相似性的系统发育分析表明，它与拉氏嗜盐古菌ZJ206密切相关。有趣的是，发现菌株HA3产生嗜盐菌素HA3，该嗜盐菌素通过超滤和色谱法进行纯化。经测试，它在高达80°C、pH 2.0 - 10.0、有机溶剂、表面活性剂和洗涤剂存在的情况下都很稳定。然而，在蛋白酶K和胰蛋白酶存在的情况下，嗜盐菌素HA3的活性完全丧失。发现它对拉氏嗜盐古菌HA10具有杀菌作用，破坏细胞边界并导致细胞死亡。嗜盐菌素HA3的分子量约为13 kDa，基质辅助激光解吸电离飞行时间串联质谱（MALDI - TOF MS/MS）分析表明与已知嗜盐菌素无同源性。其N端的十个氨基酸残基NHMNLGIILETN - COOH表明是一种新的嗜盐菌素。嗜盐菌素HA3的这些特性可能适用于控制环境和腌制食品中的嗜盐古菌。
