發(fā)布時(shí)間：2018-06-01 22:56

  本文選題：兒茶素 + EHEC　； 參考：《湖南農(nóng)業(yè)大學(xué)》2014年碩士論文

【摘要】：EHEC O157:H7是通過污染食品導(dǎo)致疫情暴發(fā)的一種常見病原微生物,且臨床上難以治療。兒茶素是茶葉中多酚類物質(zhì)的主體成分,早在神農(nóng)時(shí)期,茶就被發(fā)現(xiàn)能被用于殺菌消炎,其主要功能物質(zhì)即為茶多酚。茶多酚作為功能性抑菌成分已有大量研究與少量實(shí)際應(yīng)用。但其對(duì)EHEC O157:H7的影響卻少見報(bào)道,因此本試驗(yàn)主要是系統(tǒng)研究?jī)翰杷貙?duì)EHEC O157:H7的影響,通過活菌計(jì)數(shù)、雙向電泳等方法,考察了不同環(huán)境因素對(duì)兒茶素抑制EHEC O157:H7生長(zhǎng)的影響,模擬的人體消化道環(huán)境中兒茶素對(duì)EHEC O157:H7的殺菌作用,以及經(jīng)兒茶素處理前后EHEC O157:H7總蛋白的變化,結(jié)果顯示： 1、環(huán)境因素對(duì)兒茶素抑制EHEC O157:H7生長(zhǎng)的影響兒茶素對(duì)EHEC O157: H7最小抑菌濃度為1.25g/L；兒茶素對(duì)該菌株的抑制作用具有良好的穩(wěn)定性,在37℃的pH中性環(huán)境中,抑制作用較明顯；同時(shí),NaCl與兒茶素能起到協(xié)同抑菌作用。 2、模擬人體消化道環(huán)境中兒茶素對(duì)EHEC O157:H7的殺菌作用兒茶素對(duì)EHEC O157:H7的最小殺菌濃度為5g/L；EHEC O157:H7的生長(zhǎng)并不適應(yīng)胃液環(huán)境,活菌數(shù)與培養(yǎng)時(shí)間及兒茶素的濃度均呈負(fù)相關(guān)；在人工腸液中隨培養(yǎng)時(shí)間增長(zhǎng),兒茶素的殺菌作用越明顯,兒茶素濃度越高,活菌數(shù)越少,最小殺菌濃度為10g/L；膽鹽的存在對(duì)EHEC O157:H7的生長(zhǎng)有一定的抑制,兒茶素的加入與膽鹽有協(xié)同作用產(chǎn)生,在膽鹽環(huán)境中,兒茶素的最小殺菌濃度為10g/L。 3、兒茶素處理前后EHEC O157:H7總蛋白的變化采用蛋白質(zhì)雙向電泳技術(shù)對(duì)兒茶素引起的細(xì)菌蛋白質(zhì)變化情況進(jìn)行分析,分別設(shè)置正常組A和試驗(yàn)組B。用Image Master TM2D Platinum (Version7.0)對(duì)圖譜進(jìn)行分析得出：差值在3倍及以上的蛋白表達(dá)差異點(diǎn)中,34個(gè)蛋白點(diǎn)發(fā)生了可重復(fù)的顯著變化,2個(gè)蛋白點(diǎn)被上調(diào),12個(gè)蛋白點(diǎn)被下調(diào),未表達(dá)的蛋白有20個(gè),未產(chǎn)生新的蛋白表達(dá)。這說明了兒茶素對(duì)EHEC O157:H7蛋白的影響主要還是表現(xiàn)在對(duì)蛋白質(zhì)表達(dá)的下調(diào)和抑制某些蛋白質(zhì)的表達(dá),且兒茶素的抑制作用不會(huì)產(chǎn)生新的蛋白質(zhì)表達(dá)。
[Abstract]:EHEC O157:H7 is a common pathogenic microorganism caused by contaminated food and is difficult to be treated clinically. Catechin is the main component of polyphenols in tea. As early as Shennong period, tea has been found to be used in sterilization and anti-inflammatory, its main functional substance is tea polyphenols. Tea polyphenols as a functional bacteriostatic component has been a lot of research and a small number of practical applications. However, the effects of catechins on EHEC O157:H7 were rarely reported. The effects of catechins on EHEC O157:H7 were studied systematically. The effects of different environmental factors on the inhibition of EHEC O157:H7 growth were investigated by means of living bacteria count and two-dimensional electrophoresis. The bactericidal effect of catechin on EHEC O157:H7 and the changes of total EHEC O157:H7 protein before and after catechin treatment in human digestive tract were simulated. The results showed that: 1. The effect of environmental factors on the inhibition of EHEC O157:H7 growth by catechin was studied. The minimal inhibitory concentration of catechin on EHEC O157: H7 was 1.25 g / L, and the inhibitory effect of catechin on EHEC O157: H7 was stable in pH neutral environment at 37 鈩，

本文編號(hào)：1966071