【摘要】：雙歧桿菌(Bifidobacterium)是人和動(dòng)物腸道內(nèi)重要的生理性細(xì)菌,它的存在直接影響消化道的健康狀況。目前,在我國乃至世界范圍內(nèi),優(yōu)良雙歧桿菌資源的開發(fā)和利用已成為熱點(diǎn)。本課題通過體外及體內(nèi)實(shí)驗(yàn)方法,共計(jì)五個(gè)實(shí)驗(yàn),包括耐消化道逆環(huán)境雙歧桿菌的篩選、生長特性和生長因子以及抗氧化活性的研究。 (1)以來源于母乳嬰兒糞便、未斷奶仔豬糞便、市售雙歧桿菌制劑和本實(shí)驗(yàn)室保存的雙歧桿菌為出發(fā)菌株,采用改良MRS培養(yǎng)基,模擬人體胃腸道逆環(huán)境,對(duì)其耐消化道特性進(jìn)行了研究。研究結(jié)果表明,A03、A04和L-1菌株耐受消化道逆環(huán)境的能力最好,可用作微生態(tài)制劑菌株。同時(shí),A04菌株的生長速度較快,因此最終選定A04菌株,經(jīng)初步鑒定雙歧桿菌A04為短雙歧桿菌,定名為Bifidobacterium breve A04。 (2)應(yīng)用改良MRS培養(yǎng)基,研究了B.breve A04的生長特性,結(jié)果表明,它的適宜生長條件為:35℃-37℃、起始pH 7.0、接種量3%,最高活菌數(shù)的Ig值達(dá)到9.26,生長速度快,產(chǎn)酸能力強(qiáng),最終pH值為3.78,耐酸能力強(qiáng),延滯期相對(duì)較短,2 h后就進(jìn)入對(duì)數(shù)生長期,10 h就達(dá)到穩(wěn)定期。 (3)研究了各種因素對(duì)B.breve A04的增殖作用。結(jié)果表明,大豆低聚糖的增殖效果最明顯(P0.01),其次是低聚異麥芽糖和低聚果糖,水蘇糖則幾乎沒有增殖效果,而且當(dāng)MRS中低聚糖的濃度達(dá)到10%時(shí),對(duì)其反而具有一定的抑制作用;8種中藥在濃度為2%的時(shí)均有增殖效果,以Z_3、Z_1和Z_2效果最顯著(P0.01),但其濃度不同對(duì)B.breve A04的增殖影響截然不同;4種食品原料對(duì)B.breve A04均有促生長作用,較好的增殖作用的組合分別為:M-5%,CJ-2%,TE-2%和LE-5%。 (4)體外清除自由基的初探實(shí)驗(yàn),結(jié)果發(fā)現(xiàn),活菌體、培養(yǎng)上清及菌體破碎物均具有明顯的抗脂質(zhì)過氧化能力,能有效地清除DPPH和活性氧自由基,同時(shí)還能很好地保護(hù)DNA免受自由基損傷。 (5)利用D-半乳糖誘導(dǎo)法建立的小鼠亞急性衰老動(dòng)物模型,研究B.breve A04活菌體、培養(yǎng)上清及菌體破碎物的延緩衰老的作用。結(jié)果發(fā)現(xiàn),活菌體、培養(yǎng)上清及菌體破碎物均能降低血清和肝臟中的MDA的含量;能提高血清中的SOD、CAT活力及總的抗氧化能力;能明顯減少腦組織中的脂褐質(zhì)和MAO的含量,同時(shí)能增強(qiáng)肝臟和腦組織的蛋白質(zhì)的合成能力。結(jié)果顯示,B.breve A04活菌體、培養(yǎng)上清及菌體破碎物均具有延緩衰老的作用,其機(jī)理可能是通過多種途徑而實(shí)現(xiàn)的。
[Abstract]:Bifidobacterium (Bifidobacterium) is an important physiological bacterium in human and animal intestines. Its existence directly affects the health of digestive tract. At present, the development and utilization of excellent Bifidobacterium resources has become a hot spot in China and even the world. Five experiments were conducted in vitro and in vivo, including screening of bifidobacterium, growth characteristics, growth factors and antioxidant activity of bifidobacterium resistant to adverse environment of digestive tract. The main results are as follows: (1) the bifidobacterium from breast milk, unweaned piglets, market bifidobacterium and Bifidobacterium preserved in our laboratory were used as the starting strains. The modified MRS medium was used to simulate the adverse environment of human gastrointestinal tract. The resistance to digestive tract was studied. The results showed that strain A03 A04 and strain L-1 had the best ability to tolerate the adverse environment of digestive tract and could be used as microecological agents. At the same time, the growth rate of A04 strain was fast, so the strain A04 was selected, and the bifidobacterium A04 was identified as Bifidobacterium brevis, named Bifidobacterium breve A04. (2) the growth characteristics of B.breve A04 were studied by using the modified MRS medium. The results showed that the suitable growth conditions were: 1: 35 鈩，

本文編號(hào)：2259359