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htrA 、clpP基因缺失对变异链球菌铁代谢的影响

于丹妮1,张娅2   

  1. 1. 天津医科大学第二医院
    2. 天津医科大学第二医院口腔科
  • 收稿日期:2012-06-06 修回日期:2012-12-06 出版日期:2013-04-15 发布日期:2013-04-15
  • 通讯作者: 于丹妮

Effect of htrA or clpP mutation on iron metabolism of Streptococcus mutans

YU Dan ,ZHANG Ya   

  1. Department of Stomatology, The Second Affiliated Hospital of Tianjin Medical University, Tianjin 300211, China
  • Received:2012-06-06 Revised:2012-12-06 Published:2013-04-15 Online:2013-04-15
  • Contact: YU Dan

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摘要：

【摘要】目的 探讨高温需要蛋白A (htrA)和酪蛋白裂解酶P(clpP)单基因缺失对变异链球菌铁代谢的影响。方法 采用浊度法测定变异链球菌标准株、htrA 缺陷株和clpP 缺陷株在0.1、0.2及0.3 mmol/L铁限制条件培养基中培养 24 h的吸光度（A）值，并测定加入外源性铁或标准株分别与2种缺陷株在0.3 mmol/L铁限制培养基中混合培养24 h后的A 值。结果 与标准株相比，htrA 缺陷株在浓度0.3 mmol/L时A 值差异有统计学意义（P＜0.01）；clpP 缺陷株在0.2 mmol/L时A值差异即有统计学意义（P＜ 0.05），并且其值随铁螯合剂浓度的增加而减小。加入FeSO4培养24 h，htrA 缺陷株与标准株A 值差异无统计学意义（P＞0.05）；clpP 缺陷株的A 值低于标准株（1.002±0.014 vs1.325±0.010，P＜ 0.05）。与标准株按1∶1比例混合培养24 h，htrA 缺陷株与其单独生长时的A值的差异无统计学意义（P＞0.05）；clpP 缺陷株的A 值高于其单独培养时的A 值（10.878±0.005 vs 0.664±0.006），差异有统计学意义（P＜0.05）。结论 htrA 和 clpP基因分别在一定程度上影响变异链球菌的铁代谢。

关键词: 链球菌, 变异, htrA, 基因, clpP, 基因, 铁限制, 铁代谢

Abstract:

[Abstract] Objective  To study the effect of inactivation of high temperature requirement A (htrA) or caseinolytic protease P (clpP) on the iron metabolism of Streptococcus mutans.Methods  The nephelometer method was used to measure the absorbance of iron-limited defined medium in which Streptococcus mutans standard strains or htrA, clpP mutant strains were cultured for 24 hours. And the absorbance of all three strains was also measured and analyzed in the iron-limited defined medium with exogenous iron added or mutant and standard strains co-cultured in proportion to 1∶1 for 24 hours. Results  Compared to the standard strains, the growth of htrA mutant strains was not significantly affected until the concentration of iron chelator increased to 0.3 mmol/L (P＜0.05). The growth of clpP mutant strains was significantly affected in medium containing 0.2 mmol/L iron chelator (P＜0.05). The growth inhibition of mutant strains showed varying degrees of reversal when added exogenous iron to the iron-limited medium or 1∶1 co-cultured with standard strains. Conclusion  htrA gene or clpP gene plays an important role in iron metabolism of Streptococcus mutans.

Key words: Streptococcus mutans, htrA gene, clpP gene, irom limitation, iron metabolism, 铁代谢