Chang J Y, Lee H J, Chang H C
Department of Food and Nutrition, Chosun University, 375 Seosukdong, Donggu, Gwangju, Republic of Korea.
J Appl Microbiol. 2007 Dec;103(6):2504-15. doi: 10.1111/j.1365-2672.2007.03543.x.
To provide evidence that the production of bacteriocin by lactic acid bacteria can be enhanced by the presence of a bacteriocin-sensitive strain and identify the agent that is responsible for enhancing bacteriocin production.
One bacteriocin-producing lactic acid bacterium was isolated from kimchi. The strain GJ7 was designated as Leuconostoc citreum GJ7 based on Gram staining, biochemical properties, and 16S rRNA gene sequencing. The isolate produced a heat- and pH-stable bacteriocin (kimchicin GJ7), which has antagonistic activity against a broad spectrum of micro-organisms. Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified kimchicin GJ7 showed a single band of molecular weight c. 3500 Da. Cultures of Leuc. citreum GJ7 in the presence of thermally inactivated kimchicin GJ7-sensitive strains, Lactobacillus plantarum KFRI 464, Lactobacillus delbrueckii KFRI 347, or Leuconostoc mesenteroides KCTC 1628, increased bacteriocin production. This inducing factor was characterized and purified from Lact. plantarum KFRI 464, which showed the greatest enhancement of kimchicin GJ7 activity. The inducing factor was purified using a DEAE (diethyl aminoethyl)-Sephacel column and high-performance liquid chromatography, and yielded a single band of c. 6500 Da. N-terminal sequencing of the inducing factor identified 16 amino acids. The N-terminal sequence of the inducing factor was synthesized and examined for the induction of kimchicin GJ7 activity, and was found to induce activity, but at a level about 10% lower than that of the entire molecule.
The presence of a bacteriocin-sensitive strain, Lact. plantarum KFRI 464, acts as an environmental stimulus to activate the production of kimchicin GJ7 by Leuc. citreum GJ7. The inducing factor from Lact. plantarum KFRI 464 is highly homologous to the 30S ribosomal protein S16 from various micro-organisms. The N-terminal sequence of the inducing factor examined in this study is a very important sequence related to the inducing activity. Nevertheless, the inducing factor may not be part of the ribosomal protein S16 itself.
We believe that the present study is the first to identify an agent that is produced by one micro-organism and influences bacteriocin production in another. The bacteriocin-enhancing system described in this study could be effectively used to control the growth of other micro-organisms (sensitive cells) in food systems. Moreover, this enhancement of bacteriocin production can be applied usefully in industrial production of natural food preservatives.
提供证据证明乳酸菌产生细菌素的过程可因存在对细菌素敏感的菌株而得到增强，并鉴定负责增强细菌素产生的因子。
从泡菜中分离出一株产细菌素的乳酸菌。基于革兰氏染色、生化特性及16S rRNA基因测序，菌株GJ7被鉴定为柠檬明串珠菌GJ7。该分离株产生一种对热和pH稳定的细菌素（泡菜菌素GJ7），它对多种微生物具有拮抗活性。纯化后的泡菜菌素GJ7经Tricine - 十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳显示出一条分子量约为3500 Da的条带。在热灭活的对泡菜菌素GJ7敏感的菌株（植物乳杆菌KFRI 464、德氏乳杆菌KFRI 347或肠膜明串珠菌KCTC 1628）存在的情况下，柠檬明串珠菌GJ7的培养物中细菌素产量增加。对该诱导因子进行了特性鉴定并从植物乳杆菌KFRI 464中纯化出来，该菌株对泡菜菌素GJ7活性的增强作用最为显著。使用DEAE（二乙氨基乙基） - 葡聚糖凝胶柱和高效液相色谱对诱导因子进行纯化，得到一条约6500 Da的单一蛋白条带。对诱导因子进行N端测序鉴定出16个氨基酸。合成了诱导因子的N端序列并检测其对泡菜菌素GJ7活性的诱导作用，发现它能诱导活性，但诱导水平比整个分子低约10%。
对细菌素敏感的菌株植物乳杆菌KFRI 464的存在，作为一种环境刺激因素，可激活柠檬明串珠菌GJ7产生泡菜菌素GJ7。来自植物乳杆菌KFRI 464的诱导因子与多种微生物的30S核糖体蛋白S16高度同源。本研究中检测的诱导因子的N端序列是与诱导活性相关的非常重要的序列。然而，诱导因子可能并非核糖体蛋白S16本身的一部分。
我们认为本研究首次鉴定出一种由一种微生物产生并影响另一种微生物细菌素产生的因子。本研究中描述的细菌素增强系统可有效地用于控制食品体系中其他微生物（敏感细胞）的生长。此外，这种细菌素产量的提高可有效地应用于天然食品防腐剂的工业生产中。
