重金属胁迫下2株芽孢杆菌芽孢的形成及生物学特征

Spore Formation and Biological Characteristics of Two Bacillus Strains under Heavy Metal Ion Stress

为探明芽孢杆菌芽孢形成过程中重金属离子胁迫的生物学特征,选择枯草芽孢杆菌和简单芽孢杆菌各1株,通过芽孢染色法判断2株芽孢杆菌芽孢形成时间,同时选择4种重金属离子(Pb^(2+)、Cd^(2+)、Cr^(6+)、Hg^(2+))对2株芽孢杆菌在芽孢形成过程中进行胁迫培养,测定芽孢形成过程中的生长曲线、DNA、RNA、可溶性糖、蛋白质、多酚氧化酶(PPO)和过氧化氢酶(CAT)含量。结果表明:2株芽孢杆菌芽孢形成时间有很大差异,枯草芽孢杆菌芽孢形成的初始时间为43h,简单芽孢杆菌为16h。2株芽孢杆菌在芽孢形成过程中对4种重金属离子的耐受能力有一定差异,枯草芽孢杆菌对重金属的敏感性为Cr^(6+)>Cd^(2+)>Hg^(2+)≈Pb^(2+),简单芽孢杆菌为Hg^(2+)≈Cd^(2+)>Cr^(6+)>Pb^(2+);简单芽孢杆菌芽孢形成前期DNA、RNA含量较高,后期呈逐渐下降趋势,枯草芽孢杆菌一直呈下降趋势;可溶性糖含量逐渐增加,后期上升速率大于前期;蛋白质含量呈先下降后上升再下降趋势,PPO含量呈上升趋势,CAT含量呈先上升后下降趋势。

The spore formation time,growth curve and DNA,RNA,soluble sugar,protein,PPO and CAT content of two Bacillus strains（one Bacillus subtilis strain and one Bacillus simplexstrain）during spore formation process under Pb^（2＋）,Cd^（2＋）,Cr^（6＋）and Hg^（2＋）stress were analyzed and detected by the spore staining method and some analysis methods to explore the biological characteristics of Bacillus spores during spore formation process under heavy metal ion stress.Results：There is an obvious difference in spore formation time between B.subtilis strain and B.simplexstrain and the spore formation initial time of B.subtilis strain and B.simplexstrain is 43 hand 16 hrespectively.There is a certain difference in tolerance to four metal ions during spore formation process between B.subtilis strain and B.simplex strain and the sensitivity to four metal ions of B.subtilis strain and B.simplexstrain is Cr^（6＋）Cd^（2＋）Hg^（2＋）≈Pb^（2＋）and Hg^（2＋）≈Cd^（2＋）Cr^（6＋）Pb^（2＋）separately.The spore DNA and RNA content of B.simplex strain is high during early spore formation process and at later stage shows a gradual declining trend but the spore DNA and RNA content of B.subtilis presents a declining trend during spore formation process.The spore soluble sugar content of two Bacillus strains gradually increases and the rising speed at earlier stage of spore formation process is higher than at later stage of spore formation process.The spore protein content of two Bacillus strains shows a declining,rising and declining trend.The spore PPO content of two Bacillus strains shows a rising trend but the spore CAT content shows a first rising and then declining trend during spore formation process.