)影响ADS体内表 达的宿主和生物膜微型环境因素。例如，龋齿活跃受试者的生物膜表现为处于-有利于高 ADS表达或提供降低ADS活性的一些抑制因素。因此，具有本质上高表达ADS表型的精氨酸 分解临床菌株，和其中ADS表达对已知引起口腔龋齿的条件诸如糖可用性和酸性环境不敏 感的那些，具有在益生疗法中预防和控制口腔龋齿的用途。
[0125] 本研究揭示了，在口腔精氨酸分解中受试者内的变化的微生物基础比先前理解的 更复杂；不仅口腔生物膜的精氨酸分解潜力可与细菌的某些菌株的携带相关，而且精氨酸 分解物种显示一定范围的ADS活性作为环境因素的函数。在理解龋齿作为生态驱动的疾病 的方面，结果是高度显著的，由支持，通过缓和菌斑pH并减少龋齿的风险，高表达ADS的菌 株可协同地积极地影响菌斑生态。本研究扩大了对口腔生成碱细菌的多样性以及它们在口 腔健康和疾病中的作用的知识。
[0126] 实施例2
[0127] ADS活性和种间的拮抗作用
[0128] 引言
[0129] 本实施例描述确定精氨酸分解分离株对变形链球菌的拮抗性相互作用是否可与 精氨酸分解潜力相关。
[0130] 方法和材料
[0131] 临床分离株及筛选。如以上对实施例1所述的获得样品和铺板。
[0132] 细菌菌株、生长条件和试剂。如以上对实施例1所述的保持细菌菌株。
[0133] 16S rDNA测序和生物化学测定。如以上对实施例1描述的测序和测定。
[0134] 种间拮抗作用。为检查精氨酸分解分离株对致龋细菌变形链球菌的拮抗性相互 作用，调整BHI肉汤培养基中的变形链球菌和ADS阳性分离株的过夜培养物至相同光密 度（0D600 = 0. 5)。然后，将变形链球菌和ADS阳性分离株的6 μ 1等份彼此相邻接种在 TY-25mM半乳糖琼脂板上，如下：（i)首先接种ADS阳性分离株，24h后随后接种变形链球 菌；（ii)首先接种变形链球菌，24h后随后接种ADS阳性分离株，和（iii)同时接种ADS阳 性分离株和变形链球菌。将板培养另一个24h，在其间监测相互作用。细菌在37°C下伴随 5 % 0)2和95 %空气生长。使用AlphaEaseFC软件测量生长抑制区域。
[0135] 结果
[0136] 种间拮抗作用。为了研究ADS活性与种间拮抗作用的相关性，使用板抑制测定（表 2)检查由变形链球菌UA159与不同ADS活性分离株相互的拮抗作用。高度ADS活性分离株 显示在变形链球菌的存在下存活的能力。重要地，戈登链球菌、澳大利亚链球菌和血链球菌 的分离株显示了抑制变形链球菌UA159的生长的有效能力（表2和图4A-4D)。还值得注意 的是，许多ADS阳性分离株的生长不受变形链球菌抑制（图4A-4D)。因此，不仅口腔生物膜 的精氨酸分解潜力可与细菌的某些菌株的携带相关，而且精氨酸分解物种还显示抑制变形 链球菌、以及被变形链球菌抑制的一系列能力。
[0137] 表2:ADS阳性分离株对生长变形链球菌UA159的抑制效应。
[0138]
[0140] (**)当精氨酸分解分离株首先接种（在变形链球菌之前）时，细菌菌株的拮抗 活性水平比戈登链球菌DLl的更高；(-)精氨酸分解分离株受变形链球菌抑制；SD :标准偏 差。
[0141] 结论
[0142] 本研究揭示了，牙齿生物膜被多种精氨酸分解群落定殖，并且ADS表达在受试者 间的变化的基础可能大部分是由于ADS的调控中菌株内的可变性。共同地，结果支持，表达 高水平ADS的菌株通过缓和菌斑pH并直接拮抗已知龋齿病原菌的生长，可对菌斑生态具有 积极和协同效应。
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