【作者】 张婵；

【导师】 唐立；

【作者基本信息】 大连医科大学 ， 病原生物学， 2006， 硕士

【摘要】 目的:乳酸杆菌是人体正常菌群的重要组成成员之一,大量的研究和实践证明其具有显著的提高机体免疫力,保持宿主健康的功能。通过流行病学调查发现,长期食用经乳酸杆菌发酵的酸奶制品可降低乳腺癌、结直肠癌、胃癌及膀胱癌的发生率,但其抗肿瘤分子机制还不十分清楚。我们发现乳酸杆菌DM9811对数生长期发酵滤液中存在大量的核酸组分。已有报道乳酸杆菌基因组AT核苷酸可以通过增强TH1型免疫反应来上调机体抗肿瘤免疫水平。乳酸杆菌发酵滤液中核酸组分的性质、来源、是否在抗肿瘤效应中起到重要作用值得进行研究。本实验通过对乳酸杆菌DM9811发酵滤液中核酸组分进行定量、定性分析,观察其在体外对肿瘤细胞生长的影响及对荷瘤鼠免疫功能的影响,研究该核酸组分是否具有抗肿瘤效应,从而探讨其可能的分子作用机制及该核酸组分成为新一代抗肿瘤活性物质的可能性。方法:1.乳酸杆菌DM9811发酵滤液中核酸的提取、定性、定量。将菌液用0.45um滤器过滤,酚/氯仿抽提,无水乙醇沉淀后溶于去RNA酶水;260nm比色,观察其OD值与细菌菌数的关系;琼脂糖电泳分析滤液中核酸和乳酸杆菌胞内核酸,对RNA酶消化前后电泳条带进行对比。2.体外观察滤液中核酸对结肠癌HT-29细胞系的抑制效应。调结肠癌HT-29细胞浓度为1×106,MTT法观察抽提的核酸组分浓度分别为10ug/ml、50ug/ml、100ug/ml时对结肠癌HT-29细胞系生长的影响。3.体内观察滤液中核酸对荷瘤鼠免疫功能的影响。纯系615小鼠分为预防组、治疗组和阴性对照组,阴性对照组腹腔注射0.1ml生理盐水;预防组隔日注射核酸10ug/0.1ml·只-1,共五次,于末次注射更多还原

【Abstract】 Objective: Lactobacillus is one of the predominant microorganisms in human normal flora. A lot of research and practice has proved that it may stimulate host body immunity to maintain human health. Epidemiology investigation suggested that the habitual intake of milk products fermented by lactobacillus reduces the incidence rate of mammary cancer, colorectal cancer, stomach cancer and bladder cancer. But the molecular mechanism of its anti-tumor molecular effect is unknown. We founded a lot of nucleic acids existed in lactobacillus DM9811 fermented filtrate. Report proved the augmentation of T(H)-1 type immunologic reaction by AT oligonucleotide from lactic acid bacteria. It suggested the nucleic acids from lactobacillus is the important factor to augment cell immune response so that it has anti-tumor effect. It is the possible mechanism of lactobacillus anti-tumor effect that these lactobacillus extracelluar nucleic acids can up-regulate host immune responses level. This experiment observed the effects of nucleic acids from lactobacillus DM9811 fermented filtrate on tumor cell growth and immunological function in tumor-bearing mice, then studied its character, source, anti-tumor activity, possible molecule mechanism and investigated the possibility that it became new anti-tumor activity material.Methods: 1, Measured lactobacillus DM 9811 growth curve and chose the different time in log phase, fermented filtrate更多还原