本文選題：耐酸 + 血鏈球菌�。� 參考：《安徽醫(yī)科大學(xué)》2017年碩士論文

【摘要】：1.背景與目的變異鏈球菌是口腔主要的致齲菌之一。藥物殺滅變異鏈球菌一直是齲病防治工作的重要輔助手段,但細(xì)菌容易形成耐藥性。隨著生物工程的不斷發(fā)展,運(yùn)用益生菌替代療法得到越來越多的關(guān)注。細(xì)菌替代療法就是使用無害或者低毒力的菌株放入宿主的菌群中,防止特定病原體定植,從而起到預(yù)防、治療疾病的目的。齲病替代療法的候選菌種,除了變異鏈球菌本身外還有血鏈球菌。本研究通過逐漸降低培養(yǎng)基ph構(gòu)建血鏈球菌耐酸株,研究血鏈球菌耐酸株的適應(yīng)性耐酸能力及其相關(guān)生理變化。并通過平板實(shí)驗、PCR等技術(shù)觀察血鏈球菌耐酸株拮抗變異鏈球菌的能力,弄清血鏈球菌、變異鏈球菌在齲病發(fā)病過程中相互關(guān)系,為探索齲病替代療法提供微生物學(xué)基礎(chǔ)。2.方法2.1在逐漸降低培養(yǎng)液ph值的培養(yǎng)液中培養(yǎng)血鏈球菌,直至ph降至5.0。獲得的菌株命名為血鏈球菌耐酸株(SN)。2.2比較血鏈球菌及其耐酸株在ph7、ph5培養(yǎng)液中的生長曲線。2.3測量血鏈球菌及其耐酸株、變異鏈球菌及其耐酸株的致死ph值。2.4測量氯霉素對血鏈球菌耐酸株適應(yīng)性耐酸能力的影響。2.5通過平板實(shí)驗檢測血鏈球菌及其耐酸株與變異鏈球菌在ph7和ph5環(huán)境中的拮抗作用。2.6通過熒光定量PCR反應(yīng)比較血鏈球菌及其耐酸株的耐酸基因DnaK、GroEL的變化。3.結(jié)果3.1經(jīng)過亞致死ph培養(yǎng)的血鏈球菌耐酸株無論在正常環(huán)境還是在酸性環(huán)境生長均有優(yōu)勢。3.2血鏈球菌耐酸株較血鏈球菌致死ph降低了1.3,且有66.59%能在原致死ph存活。3.3當(dāng)含有氯霉素時,血鏈球菌耐酸株不能在原致死ph存活。3.4血鏈球菌耐酸株對變異鏈球菌的競爭排斥作用更強(qiáng)。3.5血鏈球菌耐酸株相關(guān)耐酸基因GroEL、DnaK表達(dá)上調(diào)。4.結(jié)論4.1成功構(gòu)建血鏈球菌耐酸株。4.2血鏈球菌耐酸株較血鏈球菌適應(yīng)性耐酸能力明顯提高。4.3血鏈球菌適應(yīng)性耐酸能力的提高與應(yīng)激蛋白的合成有關(guān)。
[Abstract]:1. Background & objective Streptococcus mutans is one of the major dental caries-causing bacteria. Drug killing Streptococcus mutans has always been an important aid in the prevention and treatment of caries, but bacteria are susceptible to drug resistance. With the development of bioengineering, more and more attention has been paid to the application of probiotic substitution therapy. Bacterial substitution therapy is the use of harmless or low virulent strains into the host flora to prevent the colonization of specific pathogens and thus to prevent and treat diseases. In addition to Streptococcus mutans, the candidate strains for alternative Caries Therapy are Streptococcus sanguis. In this study, Streptococcus sanguis acid resistant strain was constructed by decreasing the pH of culture medium gradually, and the adaptive acid tolerance ability of Streptococcus sanguis acid resistant strain and its related physiological changes were studied. The ability of Streptococcus sanguis acid resistant strain to antagonize Streptococcus mutans was observed by means of plate experiment and PCR, and the relationship between Streptococcus sanguis and Streptococcus mutans in the process of caries was clarified, which provided the microbiological basis for exploring alternative therapy of caries. Methods 2.1 Streptococcus sanguis was cultured in the medium that gradually decreased the ph value of the culture medium until the ph decreased to 5.0. Compared the growth curve of Streptococcus sanguis and its acid-resistant strain in ph7ph5 medium, the growth curve of Streptococcus sanguis and its acid-resistant strain were measured. The effect of chloramphenicol on adaptive acid-tolerant ability of Streptococcus sanguis and its acid-resistant strains. 2.5 Detection of Streptococcus sanguis, Streptococcus mutans and Streptococcus mutans in ph7 and ph5 environments By fluorescence quantitative PCR reaction, we compared the changes of acid-tolerant gene DnaKGlol of Streptococcus sanguis and its acid-resistant strain. 3. Results 3.1 Streptococcus sanguis acid-resistant strains cultured with sublethal ph had an advantage both in normal and acidic environments. 3.2 Streptococcus sanguis acid resistant strains decreased by 1.3 compared with Streptococcus sanguis lethal ph, and 66.59% could survive in primary lethal ph. .3.3 when chloramphenicol is present, Streptococcus sanguis acid resistant strain could not survive in the proto-lethal ph. 3.4 Streptococcus sanguis acid resistant strain had stronger competitive rejection to Streptococcus mutans. 3.5 the expression of GroELL DnaK gene associated with streptococcus sanguis acid resistance strain was up-regulated by .4. Conclusion 4.1 the successful construction of Streptococcus sanguis acid resistant strain. 4.2 Streptococcus sanguis acid resistant strain significantly improved the adaptive acid tolerance ability of Streptococcus sanguis. 4.3 the increase of adaptive acid tolerance ability of Streptococcus sanguis is related to the synthesis of stress protein.
【學(xué)位授予單位】：安徽醫(yī)科大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：R780.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前5條

1 營秀;孫應(yīng)明;陶睿;張夢潔;姜秀;;新型優(yōu)化多肽對口腔常見微生物的殺菌作用[J];醫(yī)學(xué)研究生學(xué)報;2016年04期

2 于倩;哈木拉提·吾甫爾;林靜;趙今;;伊犁黑蜂蜂膠對口腔主要致齲細(xì)菌作用的體外實(shí)驗[J];醫(yī)學(xué)研究生學(xué)報;2014年12期

3 唐玉香;徐蓉蓉;;口腔鏈球菌和變形鏈球菌耐酸相關(guān)基因ffh的同源性分析[J];口腔醫(yī)學(xué);2011年05期

4 姜葳;梁景平;李超倫;姜云濤;張明珠;;遠(yuǎn)緣鏈球菌6715耐氟菌株與親代菌株的基因表達(dá)差異[J];上海交通大學(xué)學(xué)報(醫(yī)學(xué)版);2007年02期

5 周穎,衛(wèi)華,樊明文;變形鏈球菌的適應(yīng)性耐酸能力[J];現(xiàn)代口腔醫(yī)學(xué)雜志;2003年04期

，

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