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首页> 外文期刊>Infection and immunity >Comparative Study of Streptococcus mutans Laboratory Strains and Fresh Isolates from Carious and Caries-Free Tooth Surfaces and from Subjects with Hereditary Fructose Intolerance
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Comparative Study of Streptococcus mutans Laboratory Strains and Fresh Isolates from Carious and Caries-Free Tooth Surfaces and from Subjects with Hereditary Fructose Intolerance

机译：龋齿和无龋齿表面以及遗传性果糖耐受不良受试者的变形链球菌实验室菌株和新鲜菌株的比较研究

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This study was undertaken to investigate and compare some biochemical and physiological properties related to sugar metabolism of 4 laboratory strains and 13 freshly isolated strains of Streptococcus mutans from carious and caries-free tooth surfaces and from subjects with hereditary fructose intolerance. Growth in Trypticase (BBL Microbiology Systems)-yeast extract in the presence of various sugars was almost the same for all of the fresh isolates, which grew generally better than the laboratory strains. This was especially noticeable on sucrose where the fresh isolates (including those isolated from hereditary-fructose-intolerant patients) grew two to four times more rapidly than the laboratory strains. The rate of acid production by the fresh isolates, measured with resting cells in the presence of glucose, was quite comparable to the rate of the laboratory strains. The glucose analog, 2-deoxyglucose, inhibited the acid production from glucose by two laboratory strains (6715 and ATCC 27352), but none of the fresh isolates was affected by its presence. The antibiotic, gramicidin D, which allows free diffusion of H+ across the cell membrane, inhibited the acid production of all of the strains. Phosphoenolpyruvate phosphotransferase activity toward α-methylglucoside was found in all of the laboratory and freshly isolated strains. 2-Deoxyglucose phosphotransferase activity was detected in all of the laboratory strains, but many clinical strains, especially those from hereditary-fructose-intolerant patients, contained very low or almost undetectable 2-deoxyglucose phosphotransferase activity. In one strain, the activity was restored after repeated culturing in Trypticase-yeast extract medium supplemented with glucose. Glucokinase and lactate dehydrogenase activities were detected in all of the strains tested. No marked differences were observed for these two enzymes between the fresh isolates and the laboratory strains except for three clinical strains which possessed low levels of glucokinase. The growth of all of the strains in a broth containing 4 mM glucose and 4 mM lactose was studied. Various patterns were observed: diauxie, glucose utilized before lactose but without diauxie, both sugars consumed concurrently, and lactose consumed more rapidly than glucose.
机译：进行这项研究以调查和比较与龋和无龋牙齿表面以及遗传性果糖受试者的4种实验室菌株和13种新鲜分离的变形链球菌菌株的糖代谢相关的一些生化和生理特性不宽容。对于所有新鲜分离株，在各种糖类存在下，胰蛋白酶（BBL Microbiology Systems）-酵母提取物中的生长几乎相同，其生长通常好于实验室菌株。这在蔗糖上尤其明显，在蔗糖上，新鲜分离株（包括从不耐受遗传性果糖的患者中分离出来的分离株）的生长速度是实验室菌株的2至4倍。在葡萄糖存在下用静息细胞测得的新鲜分离株的产酸速率与实验室菌株的速率相当。葡萄糖类似物2-脱氧葡萄糖通过两种实验室菌株（6715和ATCC 27352）抑制了葡萄糖中的酸生成，但是新鲜分离株均不受其影响。允许使用H + 在细胞膜上自由扩散的抗生素，即短杆菌肽D，可以抑制所有菌株的产酸。在所有实验室和新鲜分离的菌株中均发现了磷酸烯醇丙酮酸磷酸转移酶对α-甲基葡萄糖苷的活性。在所有实验室菌株中均检测到2-脱氧葡萄糖磷酸转移酶活性，但是许多临床菌株，特别是那些来自遗传-果糖不耐受患者的菌株，其2-脱氧葡萄糖磷酸转移酶活性非常低或几乎不可检测。在一种菌株中，在补充葡萄糖的胰蛋白酶-酵母提取物培养基中重复培养后，活性得以恢复。在所有测试的菌株中都检测到了葡萄糖激酶和乳酸脱氢酶的活性。在新鲜分离株和实验室菌株之间，对于这两种酶没有观察到显着差异，除了三种具有低水平葡萄糖激酶的临床菌株。研究了所有菌株在含有4 mM葡萄糖和4 mM乳糖的肉汤中的生长情况。观察到了多种模式：双糖，葡萄糖先于乳糖被利用，但没有双糖，两种糖同时消耗，乳糖的消耗比葡萄糖更快。

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