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首页> 外文期刊>Infection and immunity >In vitro growth inhibition of mastitis-causing coliform bacteria by bovine apo-lactoferrin and reversal of inhibition by citrate and high concentrations of apo-lactoferin.
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In vitro growth inhibition of mastitis-causing coliform bacteria by bovine apo-lactoferrin and reversal of inhibition by citrate and high concentrations of apo-lactoferin.

机译：牛载脂乳铁蛋白对引起乳腺炎的大肠菌的体外生长抑制作用，以及柠檬酸和高浓度载脂乳铁蛋白的抑制作用逆转。

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Bovine apo-lactoferrin (apo-Lf) was added to in vitro cultures of eight strains of coliform bacteria associated with bovine mastitis. As little as 0.02 mg of APO-Lf per ml resulted in marked inhibition of growth of all coliforms. Growth inhibition was lost if saturated Lf or iron plus apo-Lf was added to the synthetic medium. The inhibition of growth increased as the concentration of apo-Lf increased from 0.02 to 0.2 mg/ml for Klebsiella pneumoniae (OARDC-A1), Klebsiella spp. (K1-21), and Aerobacter aerogenes (55-12222) and 2 mg/ml for A. aerogenes (76-2414-1), Escherichia coli (60-Lilly), E. coli (66-S16), and Klebsiella spp. (K6-24). As the concentration of apo-Lf was increased above 0.2 or 2 mg/ml, there was less inhibition of growth except for E. coli (33-C4). Apo-Lf at 20 mg/ml was bactericidal for E. coli (33-C4). Results are compatible with the hypothesis that coliform bacteria respond to low-iron environments by production of iron-sequestering agents that complete effectively with apo-Lf for free iron. Addition of apo-Lf plus citrate resulted in loss of growth inhibition. The molar ratio (citrate to apo-Lf) was found to be more important than the absolute concentration of either component. A ratio of 75 resulted in 50% growth inhibition, whereas ratios of 300 and greater resulted in less than 10% growth inhibition. These results suggest that the ratio of citrate to Lf would be important in evaluating Lf as a nonspecific protective factor of bovine mammary secretions.
机译：将牛载脂蛋白-乳铁蛋白（apo-Lf）添加到与牛乳腺炎相关的八种大肠菌的体外培养中。每毫升低至0.02 mg的APO-Lf会明显抑制所有大肠菌的生长。如果将饱和的Lf或铁加载脂蛋白Lf添加到合成培养基中，则会失去生长抑制作用。肺炎克雷伯氏菌（OARDC-A1），克雷伯菌属（Klebsiella spp）的apo-Lf浓度从0.02增加到0.2 mg / ml时，对生长的抑制作用增加。 （K1-21），Aerobacter aerogenes（55-12222）和Aerogenes（76-2414-1），Escherichia coli（60-Lilly），E。coli（66-S16）和Klebsiella的2 mg / ml spp。 （K6-24）。随着apo-Lf的浓度增加到0.2或2 mg / ml以上，除大肠杆菌（33-C4）外，对生长的抑制作用较小。 20 mg / ml的Apo-Lf对大肠杆菌（33-C4）具有杀菌作用。结果与以下假设相吻合：大肠菌对低铁环境有反应，产生的是铁螯合剂，而铁螯合剂可与apo-Lf有效地结合生成游离铁。载脂蛋白-Lf加柠檬酸盐的加入导致生长抑制作用丧失。发现摩尔比（柠檬酸对apo-Lf）比任何一种组分的绝对浓度都重要。 75的比率导致50％的生长抑制，而300或更大的比率导致小于10％的生长抑制。这些结果表明，柠檬酸盐与Lf的比例对于评估Lf作为牛乳腺分泌物的非特异性保护因子非常重要。

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