Takanashi Shihori, Miura Ai, Abe Koko, Uchida Junya, Itoi Shiro, Sugita Haruo
Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan.
Folia Microbiol (Praha). 2014 Jul;59(4):289-93. doi: 10.1007/s12223-013-0297-8. Epub 2014 Jan 7.
Lactococcus lactis subsp. lactis has been isolated from the intestines of marine fish and is a candidate probiotic for aquaculture. In order to use the bacterium as a probiotic, properties such as bile tolerance need to be assessed. Here, we compared bile tolerance in L. lactis strains derived from different sources. Three L. lactis subsp. lactis strains from marine fish (MFL), freshwater fish (FFL), and cheese starter (CSL) were used along with an Lactococcus lactis subsp. cremoris strain from cheese starter (CSC). The four strains were grown under various culture conditions: deMan-Rogosa-Sharpe (MRS) broth containing bile salts/acids, MRS agar containing oxgall, and phosphate-buffered saline (PBS) containing fish bile. Survival/growth of the strains in the presence of sodium cholate and sodium deoxycholate varied in the order MFL, CSL > CSC > FFL; in the presence of sodium taurocholate, the order was MFL > CSL > CSC > FFL. In liquid media containing various concentrations of oxgall, survival of the strains was observed in the order MFL > CSL > FFL and CSC. The survival of MFL was not affected by bile collected from the goldfish (Carassius auratus subsp. auratus) or the puffer fish (Takifugu niphobles), although the other strains showed significant inhibition of growth. It is a novel and beneficial finding that MFL has the highest resistance to bile acid.
乳酸乳球菌乳酸亚种已从海水鱼肠道中分离出来，是水产养殖中益生菌的候选菌株。为了将该细菌用作益生菌，需要评估其诸如胆汁耐受性等特性。在此，我们比较了不同来源的乳酸乳球菌菌株的胆汁耐受性。使用了三株来自海水鱼（MFL）、淡水鱼（FFL）和奶酪发酵剂（CSL）的乳酸乳球菌乳酸亚种菌株，以及一株来自奶酪发酵剂的乳酸乳球菌乳脂亚种菌株（CSC）。这四株菌株在各种培养条件下生长：含有胆盐/酸的德氏改良罗氏培养基（MRS）肉汤、含有牛胆汁的MRS琼脂以及含有鱼胆汁的磷酸盐缓冲盐水（PBS）。在胆酸钠和脱氧胆酸钠存在的情况下，菌株的存活/生长情况顺序为MFL、CSL > CSC > FFL；在牛磺胆酸钠存在的情况下，顺序为MFL > CSL > CSC > FFL。在含有不同浓度牛胆汁的液体培养基中，菌株的存活情况顺序为MFL > CSL > FFL和CSC。MFL的存活不受从金鱼（鲫属鲫亚种）或河豚（黑鳃兔头鲀）收集的胆汁影响，尽管其他菌株显示出生长受到显著抑制。MFL对胆汁酸具有最高抗性是一个新颖且有益的发现。
