中国茶预防龋病的实验研究

目的 探讨茶浸液中氟对变形链球菌（简称变链菌）致龋作用的动物实验研究分析。方法 用致龋性食物和茶浸液饲养接种了Ｓ．Ｓｏｂｒｉｎｕｓ６７１５菌株的大鼠磨牙，观察茶浸液对变链菌的生长及致龋作用影响，设龙井茶（Ｂ组）、乌龙茶（Ｃ组）、涪陵红茶（Ｄ组）各实验组与双蒸馏水对照组（Ａ组）比较。结果 实验组与对照组牙菌斑指数和龋蚀指数有显著性差异，组间差异顺序为Ｄ组〉Ｂ组〉Ａ组。此抑菌程度与茶氟含量呈正相关关系     

罗汉果浸出液对变链菌致龋作用的实验室研究

目的为探讨含蔗糖外甜味素的天然植物果———罗汉果对变形链球菌（简称变链菌）致龋作用的影响。方法用实验室比浊法观察罗汉果浸出液对变链菌的生长、玻棒粘附和产酸的影响，并设蔗糖、甜菊糖、果糖和葡萄糖实验组与其比较。结果显示变链菌在罗汉果试验液中的生长及酵解明显低于其它实验组，包括甜菊糖组（Ｐ＜００１）；变链菌对玻棒的粘附在罗汉果组中最低。结论罗汉果甜度高、粘度小，其抑制变链菌致龋作用优于甜菊糖，提示了它可能作为无致龋性甜味剂的应用前景。     

氟微量元素矿化液对变链菌生长及粘附影响的研究

目的：由于具有强的致龋潜力耐氟菌株的产生，氟化物的单一应用存在一定的局限性。本组观察含氟的微量元素矿化液对变链菌生长和粘附的影响。方法：采用厌氧菌连续培养技术，用菌液的吸光度（ＡＢＳ）和菌落计数作指标，描述矿化液对变链菌生长繁殖的影响；用＾３Ｈ－胸腺嘧啶核苷（＾３Ｈ－ＴｄＲ）标记变链菌的方法，检测矿化液对变链菌粘附的影响。结果：放化液及氟微量元素矿化液均具有抑制细菌生长的作用，同时能抑制变链菌对Ｓ     

唾液对变链粘附作用的影响

用放射性同位素３Ｈ－胸腺嘧啶核苷标记变链Ｓ．ｍｕｔａｎｓＪＢＰ株（血清Ｃ型）及Ｓ．ｓｏｂｒｉｎｕｓ６７１５株（血清ｇ型），观察兔全唾液对这两种细菌在羟磷灰石（ＨＡ）表面粘附的影响．结果发现，ＪＢＰ和６７１５在无唾液包被的ＨＡ上的粘附无明显差异（Ｐ＞０．０５），但经唾液包被ＨＡ后ＪＢＰ粘附量明显多于６７１５（Ｐ＜０．０１），说明唾液成分可促进Ｃ型变链的粘附，但对ｇ型变链的粘附影响不大．     

唾液对变形链球菌Mutans和变形链球菌Sobrinus粘附的影响

用＾３Ｈ标记变形链球菌遗传分型Ⅰ型Ｓ．ｍｕｔａｎｓＪＢＰ和ⅢＳ．ｓｏｂｒｉｎｕｓ６７１５，观察细菌在经兔唾液包被的羟磷灰石微珠表面的粘附量，以研究唾液对两种菌粘附的影响。结果表明，Ｓ．ｍｕｔａｎｓＪＢＰ和Ｓ．ｓｏｂｒｉｎｕｓ６７１５对经唾液包被的ＨＡ上的粘附量有明显差异，Ｉ型ＪＢＰ的粘附量显著多于Ⅲ型６７１５，在无唾液包被的ＨＡ上，两者粘附量无明显差异。结果说明变形链球菌Ｉ型Ｓ．ｍｕｔａｎｓ粘附的     

pH值对乳杆菌和变链菌生长的影响

目的了解培养基pH值对乳杆菌和变链菌生长的影响。方法本实验采用OD值法对两菌在不同pH值培养基中的生长量进行了测定。结果培养基PH值为6．2时，两菌的生长量一致。结论在比较两菌致龋性研究中，宜采用pH6．2的培养基。     

花多酚、鞣酸抗细菌生长、粘附能力的研究

目的：探讨茶多酚、鞣酸对致龋菌生长、粘附能力的影响。方法：参照已有的多酚、鞣酸溶液MIC,观察不同浓度药液中变边菌Ing、6715和粘放菌ATCC19246的生长、粘附情况。结果：茶多酚对变链菌lng的生长有较强的抑制能力,而鞣酸对三种受试菌的生长均有较强抑制能力,二药对变链菌Ing、6715有轻微的抗粘附活性。,对粘放菌19246则无作用。结论：茶多酚、鞣酸具有一定的抑制细菌生长能力,并变链菌Ing、6715有轻微的抗粘附活性。     

乳过氧化物酶系统对血型链球菌和变形链球菌生长的影响

目的：探讨乳过氧化物酶系统在口腔微生态环境中对链球菌族生长和菌种平衡的影响。方法：将血型链球菌３４和变形链球菌Ｉｎｇｂｒｉｔ（ｃ）分为纯培养和混合培养等实验组，用连续培养方法，给予乳过氧化物酶（ＬＰＯ）、硫氰酸盐、Ｈ２Ｏ２，采用活菌计数法检测两菌的生长状态。结果：血型链球菌３４在参入乳过氧化物酶因素的培养液中，其生长量较为平稳，有较强的抵抗力，而变形链球菌的生长量显著下降；混合培养中两菌的生长量均有所提高。结论：两菌的共生可以提高它们对乳过氧化物酶系统的抵抗力；血形链球菌ＬＰＯ系统的高抵抗力与其在早期牙菌斑中占优势是相一致的。     

山梨醇对变形链球菌致龋性影响的体外实验研究

作者分别在３％蔗糖培养基，５％山梨醇培养基和含５％山梨醇的蔗糖培养基中培养变形链球菌，比较三种培养基中变链菌在多个环节上的致龋能力。发现变链菌经三种培养后，吸附能力无差别，但在山梨醇中培养时，变链菌生长缓慢，产酸少，特别是乳酸量远低于另两组，培养基ｐＨ值下降轻微。在蔗糖培养基中加入山梨醇后，细菌的生长和产酸都有所减弱。表明山梨酵致龋性低，代替蔗糖可减少龋齿。     

质子通透性与变形链球菌耐酸性关系的研究

变形链球菌 (以下简称变链菌 )是公认的龋病致病菌 ,其致龋性除与其对牙面的粘附能力和产酸性有关外 ,还与其耐酸性密切相关。对致龋菌而言 ,耐酸性 (ａｃｉｄｔｏｌｅｒａｎｃｅ/ａｃｉｄｕ ｒａｎｃｅ)是指细菌能在低 ｐＨ值环境中生长和代谢碳水化合物产酸的性能。致龋菌均能产酸 ,但并非所有能产酸的细菌均能致龋 ,因为随着菌斑ｐＨ值的降低 ,一些细菌失去产酸能力 ,在临界 ｐＨ值时 ,只有少数耐酸的细菌如变链菌和乳杆菌能生长[1] 。变链菌是菌斑中最耐酸的细菌之一 ,其各遗传种在ｐＨ值低至 4 .0时仍能代谢蔗糖产酸[2 ,3] ,而其它很多…     

Colonization of rat molar teeth by mutans streptococci with different salivary agglutination characteristics

The oral implantation of salivary agglutination-positive and -negative mutans streptococci was studied using streptomycin resistant (StrR) organisms. StrR Streptococcus mutans strains Ingbritt and NCTC 10449 are agglutinated by rat saliva and the StrR strains Streptococcus sobrinus 6715-13 and Strep. mutans GS5 are not. Four groups of Sprague-Dawley rats were inoculated orally with each organism (one per group) and fed a sucrose diet. A further two groups of animals were similarly inoculated with either the agglutination-positive Strep. mutans Ingbritt or the agglutination-negative Strep. sobrinus 6715-13 and fed a glucose diet. StrR streptococci were recovered from smooth-surface dental plaque of all animals on the sucrose diet with no significant difference in the recovery of agglutination-positive Strep. mutans strains Ingbritt and NCTC 10449 and agglutination-negative Strep. mutans GS5. However, the recovery of agglutination-negative Strep. sobrinus 6715-13 from smooth-surface plaque of animals on either the sucrose or the glucose diets was significantly lower than that of the other strains. Agglutination-positive Strep. mutans Ingbritt colonized smooth enamel surfaces of animals on the sucrose and the glucose diets in numbers that were not significantly different. However, the colonization of such surfaces by agglutination-negative Strep. sobrinus 6715-13 was significantly enhanced by the sucrose diet. Agglutination-positive and -negative StrR mutans streptococci were recovered from fissure plaque of all inoculated sucrose-fed animals in numbers that were not significantly different. Successful colonization of smooth enamel surfaces by the StrR streptococci resulted in increased smooth-surface caries.(ABSTRACT TRUNCATED AT 250 WORDS)     

几种制剂对口腔主要致龋菌抑制作用的比较

目的 :研究玉洁纯、硫酸锌、茶多酚以及它们相对配伍的制剂应用于龋病预防的可能性。方法 :采用液体稀释法体外抑菌实验比较玉洁纯、硫酸锌、茶多酚以及它们配伍使用时对口腔主要致龋菌S .mutansIngbritt、S .sobrinus　 6 715的抑制效果。结果 :以上三种制剂均能有效地抑制主要致龋菌的生长 ,其中玉洁纯的抑菌效果最为显著 ;硫酸锌和茶多酚都不能有效地促进玉洁纯的抑菌作用。结论 :玉洁纯作为一种高效低毒的抑菌剂可以考虑用于龋病预防 ,硫酸锌对玉洁纯抑菌效果的影响有待进一步研究。     

Effects of extracellular plaque components on the chlorhexidine sensitivity of strains of Streptococcus mutans and human dental plaque

An in vitro study was undertaken to determine the effects of sucrose-derived extracellular plaque components on the sensitivity of selected oral bacteria to chlorhexidine (CX). Cultures of Streptococcus mutans HS-6, OMZ-176, Ingbritt C, 6715-wt13, and pooled human plaque were grown in trypticase soy media with or without 1% sucrose. The sensitivity to CX of bacteria grown in each medium was determined by fixed-time exposure to CX and subsequent measurement of 3H-thymidine uptake. One-hour exposure to CX at concentrations of 10(-4) M (0.01% w/v) or greater substantially inhibited subsequent cellular division among all the S. mutans strains and human plaque samples tested. An IC50 (the CX concentration which depressed 3H-thymidine incorporation to 50% of control level) of close to 10(-4) M was noted for S. mutans strains HS-6, OMZ-176, and 6715-wt13 when grown in the presence of sucrose. The same strains grown in cultures without added sucrose showed about a ten-fold greater sensitivity to CX (IC50 close to 10(-5) M). A three-fold difference was noted for S. mutans Ingbritt C. Only a slight increase in the IC50 was noted for the plaque samples cultured in sucrose-containing media, but their threshold for depression of 3H-thymidine uptake by CX was lower than that for the sucrose-free plaque samples. The study showed that extracellular products confer some protection against CX to the bacteria examined, and provided an explanation for the disparity between clinically-recommended concentrations for plaque suppression and data on in vitro susceptibility.(ABSTRACT TRUNCATED AT 250 WORDS)     

茶色素抑制变形链球菌的实验研究

目的研究茶色素对变形链球菌的抑制作用及其机制。方法以茶多酚为对照,采用液体稀释法体外抑菌实验比较不同纯度茶色素对变链菌族的变形链球菌和远缘链球菌生长、产酸和形态学的影响。结果纯度为20%、40%、60%的茶色素均能抑制变链菌生长,其中纯度为40%的茶色素抑菌效果最佳,与纯度90%的茶多酚相当,两者均能明显抑制变链菌产酸(P<0.05),透射电镜观察发现茶色素主要引起变链菌胞质空泡性变,茶多酚则破坏细菌细胞壁,两者抑菌机理不同。结论不同纯度茶色素中,纯度为40%的茶色素抑制变链菌效果最佳,抑菌过程中茶色素各个组分存在着协同作用。     

有机弱酸对变链菌产酸作用的影响

目的 探讨有机弱酸苯甲酸、苹果酸、柠檬酸对口腔主要致龋菌变形链球菌的作用，并与氟化钠进行比较；探讨上述弱酸作为防龋剂的可能性。方法 将变形链球菌Smutans Ingbritt置入含有不同浓度的氟化钠、苹果酸、柠檬酸、苯甲酸的液体培养基TSB中生长48h，测定菌液的终末pH值，推测上述弱酸对细菌产酸能力的抑制作用，结果 苯甲酸、苹果酸、柠檬酸的抑菌所需浓度较氟化钠浓度高，且具浓度依赖性。结论 氟化钠抑制变形链球菌产酸作用最好；而有机弱酸苯甲酸、苹果酸、柠檬酸在较高浓度下，才有不同程度抑制变形链球菌产酸作用，但该浓度却有可能对牙釉质产生脱矿作用。     

不同浓度硒对变形链球菌粘附功能的影响

目的：通过体外模拟口腔环境,观察不同浓度硒作用下,变形链球菌粘附作用的改变情况,以确定硒是否对变形链球菌粘附功能产生影响。方法：4个实验组培养基中分别含硒0.4、0.8、1.0、2.0（×10-6）,对照组培养基含硒浓度为0。各组分别加入0.1mL吸光度调至0.33的菌液,及稀释后的3H-TdR（调整各组浓度至0.37×107Bq/L）,厌氧连续培养24h。将羟磷灰石研磨过筛、灭菌,用全唾液处理以形成人工获得性膜,用人白蛋白包被,分别在每组中加入5mg,继续培养1h,离心后收集沉淀,加入闪烁液,液闪仪测定。结果：与对照相比,加入不同浓度硒培养的变链菌每分钟闪烁强度值（CPM）均有所降低,单因素方差分析各组间有显著性差异（P〈0.05）,说明变形链球菌粘附在羟磷灰石颗粒上的数量较少。结论：一定浓度的硒可使变形链球菌在体外形成的羟磷灰石获得性膜上的粘附量减少,这可能是硒抑制了变形链球菌的粘附功能。     

Adaptation by Streptococcus mutans to acid tolerance

Our previous continuous culture studies with strains of Streptococcus mutans have indicated that the organism has the capacity of adapt to growth in acidic environments. This study was undertaken to examine this question in more detail. S. mutans Ingbritt and the phosphotransferase system (PTS)-defective mutant, S. mutans DR0001/6, were grown in continuous culture at pH 7.5 and 5.5 or 5.1, and the pH optimum for glucose uptake and glycolysis and the capacity of the cells to generate pH gradients were determined over the pH range 4.5 to 8.0 with steady state, washed cells. In addition, the proton permeability of the cells was measured over the pH range by an acid pulse technique. The results indicate that the pH optimum for glucose uptake by S. mutans Ingbritt grown at pH 7.5 was 7.5 and this optimum shifted to 7.0 and 6.0 for cells grown at pH 5.5 and 5.1, whereas with the S. mutans DR0001/6, the optimum shifted from 7.5 to 7.0 for the pH 5.5 cells. A similar shift in the pH optimum for glycolysis was observed for the 2 strains, and this was particularly pronounced for cells incubated with glucose in the presence of gramicidin to dissipate proton gradients. The capacity of the cells to generate pH gradients was related to their metabolic activity, and although larger gradients were not formed by the pH 5.5 cells, these cells were nevertheless capable of maintaining gradients at a lower pH; S. mutans DR0001/6 generated 2-fold larger pH gradients at pH 5.5 than S. mutans Ingbritt.(ABSTRACT TRUNCATED AT 250 WORDS)     

单克隆抗体对茸毛链球菌主要表面蛋白的免疫定位观察

目的：研究所制备的单抗与其相应的非变性抗原ＰＡｇ 的反应，并直观显示ＰＡｇ 在茸毛链球菌原位的分布。方法：采用间接免疫金标技术，通过透射电镜观察，并设置多抗以及变形链球菌和鼠链球菌作为对照。结果：抗ＰＡｇ的单抗可与茸毛链球菌发生反应，与变形链球菌反应不明确，与鼠链球菌不发生反应。结论：所制备的单抗能与ＰＡｇ 特异性结合，ＰＡｇ 可能与茸毛链球菌表面茸毛层相关。     

变形链球菌和远缘链球菌耐氟菌株超微结构观察

目的：探讨变形链球菌和远缘链球菌耐氟突变后，其超微结构变化及氟化物对细菌结构的影响。方法：将变形链球菌和远缘链球菌分为3组：A为正常对照组；B为加氟孵育组；C为耐氟菌株组。透射电镜观察3组细菌的超微结构。结果：与正常亲代菌株相比，加氟孵育后的菌株及耐氟菌株菌体出现不同程度超微结构改变，包括胞浆电子密度减低，细胞肿胀，内容物外溢，远缘链球菌链状结构消失等。结论：变形链球菌和远缘链球菌与氟共同孵育及耐氟突变后，其超微结构发生了改变，表现为自溶活动及解链活动增强。     

变形链球菌耐氟菌株的诱导及产酸性的实验研究

目的　探讨变形链球菌耐氟菌株致龋毒力的变化。方法　在含有不同氟浓度的TSA上逐步诱导变形链球菌 (S mutansIngbritt)产生耐氟菌株Ingbritt FR ,用气相色谱法检测耐氟菌株的产酸量及降低pH值的能力 ,并与亲代野生菌株进行比较。结果　Ingbritt FR在体外诱导成功并稳定传代培养 ;当氟化物存在时 ,耐氟菌株的产酸量大于亲代野生株 ;无氟化物存在时 ,初始pH≥ 5 5时其产酸量小于亲代株 ,pH <5 5时则大于亲代株 ,差异有显著性。结论　变形链球菌耐氟菌株具有致龋性 ;在菌斑正常氟浓度情况下 ,其致龋力可能大于亲代野生株。