EFFECTS OF CARBOHYDRATE PULSES AND PH ON POPULATION SHIFTS WITHIN ORAL MICROBIAL COMMUNITIES INVITRO
EFFECTS OF CARBOHYDRATE PULSES AND PH ON POPULATION SHIFTS WITHIN ORAL MICROBIAL COMMUNITIES INVITRO
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DOI：
10.1177/00220345890680090101
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发表时间：
1989-09-01
影响因子：
7.6
通讯作者：
MARSH, PD
中科院分区：
文献类型：
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作者：
BRADSHAW, DJ;MCKEE, AS;MARSH, PD
使用混合培养恒化器系统来区分碳水化合物可用性本身和碳水化合物代谢产生的低pH对微生物群落内细菌比例的影响。9种口腔细菌在pH 7下生长，并连续10天用葡萄糖脉冲。在一个恒化器中，pH在整个实验期间自动保持在7，而在另一个恒化器中，在每次脉冲后停止pH控制6小时。中性pH值下的葡萄糖脉冲对微生物群落的组成影响不大。只有粘性放线菌和韦荣球菌的比例增加，干酪乳杆菌和变形链球菌保持在较低的水平（分别为0.2%和1.0%）。醋酸盐和丙酸盐是代谢的主要终产物;乳酸盐水平较低。相比之下，当pH值在每次葡萄糖脉冲后下降时，微生物群落的组成发生了显着变化。L. casei和S.变形链球菌在总计数中的比例和绝对数量均增加，如V.dispar，而其他革兰氏阴性微生物（中间拟杆菌、具核梭杆菌和亚黄奈瑟氏菌）和血链球菌的数量显著减少。乳酸盐形成代谢终产物的主要部分。连续的葡萄糖脉冲导致微生物区系的放大变化和稳定的更大的产酸速率和最终程度。这与报告的响应于频繁碳水化合物摄入的体内口腔微生物区系的变化一致。数据分析强烈表明，碳水化合物代谢产生的pH值，而不是碳水化合物本身的可用性，是负责广泛报道的组成和代谢的口腔微生物菌群在体内的变化。
A mixed culture chemostat system was used to distinguish between the effects of carbohydrate availability per se and the low pH generated from carbohydrate metabolism on the proportions of bacteria within microbial communities. Nine oral bacteria were grown at pH 7 and pulsed with glucose on ten consecutive days. In one chemostat, the pH was maintained automatically at 7 thoughout the experimental period, while in the other, pH control was discontinued for six hours after each pulse. Glucose pulses at neutral pH had little effect on the composition of the microflora. Only the proportions of Actinomyces viscosus and Veillonella dispar increased; Lactobacillus casei and Streptococcus mutans remained at low levels (0.2% and 1.0%, respectively). Acetate and propionate were the predominate end-products of metabolism; lactate levels were low. In contrast, when pH was allowed to fall after each glucose pulse, the compostion of the microflora altered dramatically. The amounts of L. casei and S. mutans increased both as a proportion of the total count and in absolute numbers, as did V. dispar, whereas the amounts of the othe Gram-negative organisms (Bacteroides intermedius, Fusobacterium nucleatum, and Neisseria subflava) and Streptococcus sanguis were considerably reduced. Lactate formed a major portion of the metabolic end-products. Successive glucose pulses resulted in both amplified changes in the microflora and a steadily greater rate and final extent of acid production. This is in agreement with the reported shifts in the oral microflora in vivo in response to frequent carbohydrate intake. Analysis of the data strongly suggests that the pH generated from carbohydrate metabolism, rather than carbohydrate availability per se, is responsible for the widely reported shifts in composition and metabolism of the oral microflora in vivo.