摘要
本文采用单因素实验,优化AI-2合成的孵育温度、pH、酶浓度以及孵育时间。利用优化的合成条件,成功合成具有生物活性的AI-2,活性约为阳性对照的2倍。添加合成的AI-2到MRS培养基中,研究AI-2对植物乳杆菌KLDS1.0391生长和细菌素合成的影响,并采用实时荧光定量PCR分析培养15 h的植物乳杆菌KLDS1.0391的细菌素结构基因pln EF的转录水平。结果表明:AI-2合成的最优条件为:0.5 mg/m L Pfs蛋白、1.0 mg/m L Lux S蛋白、2 mmol/L SAH,p H7.5,37℃孵育5 h。添加合成的AI-2对植物乳杆菌的生长无明显影响;培养3 h后,相同培养时间时添加AI-2的实验组对枯草芽孢杆菌ATCC6633的抑菌圈直径显著高于空白对照和阴性对照组(p<0.01);添加AI-2的实验组的pln EF基因的表达量上调至空白对照的2.89倍。本研究成功优化AI-2的体外合成条件;添加合成的AI-2对植物乳杆菌KLDS1.0391细菌素合成有促进作用,且这种促进作用可能与pln EF基因转录水平上调有关。
The factors including incubation temperature, pH, enzyme concentration and incubation time were optimized by single-factor experiment design.Then Al-2 was synthesized under the optimum conditions.The biological activity of the synthesized Al-2 in vitro,was about i-fold higher than the positive control. In order to research effect of Al-2 on the growth and bacteriocin synthesis, Lactobacillus plantarum KLDS1.0391 was cultured in MRS broth supplemented with Al-2 synthesized.The expression level of plnEF gene encoding bacteriocin of Lactobacillus plantarum KLDSl.0391 cultivated for 15 h was studied by RT-PCR.The results showed that the optimum conditions for the synthesis of AI-2 in vitro were determined as follows.the SAH concentration of 2 mmol/L,the LuxS protein concentration of 1.0 mg/mL, the Pfs protein concentration of 0.5 mg/mL, the incubation temperature of 37℃,pH of 7.5,and the incubation time of 5 h.Growth rate of Lactobacillus plantarum had no significant change, and the inhibition zone against Bacillus subtilis ATCC6633 increased significantly after cultivated in the MRS broth supplemented with Al-2 synthesized for 3 h.And the expression level of plnEFgene of the experimental group was i.89-fold higher than the blank control.In this study, the conditions for the synthesis of Al-2 in vitro were optimized. Al-2 played an obvious positive regulatory role on bacteriocin production, and the regulatory effect may be associated with the increases of transcriptional level of plnEF gene.
出处
《食品工业科技》
CAS
CSCD
北大核心
2015年第23期199-203,218,共6页
Science and Technology of Food Industry
基金
教育部博士学科点专项科研基金(20122325110017)
黑龙江省教育厅科学技术研究(重点)项目计划(12521Z002)
