Estimation of lactic acid bacterial cell number by DNA quantification
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- Ishii Masaki
- Genome Pharmaceuticals Institute Co., Ltd.
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- Matsumoto Yasuhiko
- Teikyo University Institute of Medical Mycology
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- Sekimizu Kazuhisa
- Genome Pharmaceuticals Institute Co., Ltd. Teikyo University Institute of Medical Mycology
抄録
<p>Lactic acid bacteria are provided by fermented foods, beverages, medicines, and supplements. Because the beneficial effects of medicines and supplements containing functional lactic acid bacteria are related to the bacterial cell number, it is important to establish a simple method for estimating the total number of lactic acid bacterial cells in the products for quality control. Almost all of the lactic acid bacteria in the products are dead, however, making it difficult to estimate the total number of lactic acid bacterial cells in the products using a standard colony-counting method. Here we estimated the total lactic acid bacterial cell number in samples containing dead bacteria by quantifying the DNA. The number of viable Enterococcus faecalis 0831-07 cells decreased to less than 1 × 10-8 by 15 min of heat treatment at 80°C. The amount of extracted DNA from heat-treated cells was 78% that of non-heated cells. The number of viable Lactobacillus paraplantarum 11-1 cells decreased to 1 × 10-4 after 4 days culture. The amount of extracted DNA of the long-cultured cells, however, was maintained at 97%. These results suggest that cell number of lactic acid bacteria killed by heat-treatment or long-term culture can be estimated by DNA quantification.</p>
収録刊行物
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- Drug Discoveries & Therapeutics
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Drug Discoveries & Therapeutics 12 (2), 88-91, 2018-04-30
特定非営利活動法人 バイオ＆ソーシャル・サイエンス推進国際研究交流会