A research group led by Professor Hisashi Sato of the Graduate School of Engineering, Hokkaido University, and Researcher Reiko Hirano of Cellspect, a medical equipment manufacturer, has developed a new method for measuring the intensity of fluorescent dyes with high sensitivity and examining the number of Escherichia coli.The measurement time is one tenth of the conventional one, and it is possible to survey a large number of samples at once at low cost.
According to Hokkaido University, the number of E. coli has been measured by culturing E. coli using an agar medium or liquid medium and examining the number of colonies, but it took about 24 hours to obtain the results.The research group devised a method to automatically measure the fluorescence intensity of the medium every 37 minutes while adding a fluorescent substrate to the liquid medium of E. coli and warming it to 10 degrees.
The fluorescence intensity is proportional to the number of E. coli, but since the enzyme possessed by E. coli decomposes only the substrate, the number of E. coli can be increased by using a substrate that does not fluoresce until the enzymatic decomposition starts and fluoresces only after the decomposition. It's easy to find out.
Furthermore, we succeeded in reducing the measurement time to about 2 hours, and 1 samples could be examined at the same time in one measurement, and the measurement cost per sample could be suppressed to about 96 yen.
The research group has succeeded in measuring the number of E. coli in low-concentration samples, river water, and milk.In the future, it will be used in water purification plants, food processing plants, wells in developing countries, etc.It is likely to attract the attention of the beverage and food industry as it will quickly reveal water and food pollution.
