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采用LB固体培养基富集培养法,分别从苏玉糯4号玉米种子和安徽池州一某茶园幼嫩茶树叶片中分离到一株内生细菌,经细菌16 srDNA全序列测定为Bacillus cereus,表明苏玉糯4号玉米种子和此地茶叶中细菌种类较单一;为了探讨稀土元素对此细菌的生理功能及作用机理,在LB培养基中附加一定浓度氧化铕,滤纸片法显示氧化铕可以使分离得到的B.cereus增强对0.135%升汞、9%苯酚、75%乙醇和80万单位/mL青霉素溶液的抗性,抑菌圈直径与不加氧化铕的对照相比有显著差异(p<0.05),但氧化铕浓度太大(500 mg/L)时,又会使分离到的细菌对上述四种供试化学物质的抗性下降。光电比浊法和扫描电镜显示,氧化铕可以促进分离得到的内生细菌个体生长和繁殖;氧化铕促进细菌分裂的作用可被钙调蛋白抑制剂氯丙嗪抑制,表明氯丙嗪也可以调节原核生物体内类钙调蛋白的功能,氧化铕促进细菌繁殖的机理可能与类钙调蛋白有关。
Endophytic bacteria were isolated from the leaves of young tea plants of Suyu No.4 maize seeds and a tea plantation in Chizhou, Anhui Province using LB solid medium enrichment culture method. Bacillus was identified as Bacillus cereus by the sequence of 16 srDNA In order to explore the physiological function and mechanism of rare earth elements on this bacterium, some concentrations of europium oxide were added to LB medium, and the filter paper method showed that europium oxide could separate The resulting B.cereus enhanced resistance to 0.135% mercuric chloride, 9% phenol, 75% ethanol and 800,000 units / mL penicillin solution with significant differences in zone of inhibition diameter as compared to the control without europium oxide (p < 0.05). However, when the concentration of europium oxide is too large (500 mg / L), the resistance of the isolated bacteria to the above four tested chemical substances will be decreased. Photoelectric turbidimetry and scanning electron microscopy showed that europium oxide can promote the growth and reproduction of isolated endophytic bacteria; the role of europium oxide to promote bacterial division can be suppressed by calmodulin inhibitor chlorpromazine, indicating that chlorpromazine can also regulate The function of calmodulin in prokaryotes and the mechanism of europium oxide in promoting bacterial growth may be related to calmodulin.