What is the method for detecting E. coli in drinking water

Escherichia coli is a relatively common bacteria that is harmful to the human body. It is commonly found in our drinking water. If you drink water containing E. coli for a long time, it will cause great harm to your body. To this end, check the water for E. coli. So what is the method for detecting E. coli in drinking water? Many friends are curious about this question. Let me give you a brief introduction below.

What is the method for detecting E. coli in drinking water?

1. A method for rapid detection of Escherichia coli in drinking water, characterized in that it comprises the following steps:

(1) Collection of microorganisms in water samples and extraction of their DNA: Filter the water sample using a sterilized filter membrane or filter, wash the filter membrane in an EP tube filled with sterile water, centrifuge, discard the supernatant and set aside;

(2) Extraction of microbial DNA from water samples: A. Add TE buffer to the EP tube to resuspend it; B. Add SDS and proteinase K, mix well, and incubate for 45 min to 1 h; C. Add chloroform/isoamyl alcohol, mix well, centrifuge, and transfer the supernatant to a new EP tube; D. Add an equal volume of phenol/chloroform/isoamyl alcohol, mix well, centrifuge, and transfer the supernatant to a new EP tube; E. Add isopropanol, mix gently until the DNA precipitates, and centrifuge; F. Discard the supernatant, wash the precipitate with ethanol, and dry it; G. Redissolve the precipitate in TE buffer and shake well; H. Use a UV spectrophotometer to measure the OD value of the extracted genomic DNA template and calculate its DNA concentration. The calculation method is: DNA concentration (μg/μL) = OD value 260nm × sample dilution factor × 50/1000 I. Label the genomic DNA template, store it, and set it aside;

(3) PCR amplification; Reaction primers: Upstream primer: 5'-tgttcagtggcaagagtt-3' Downstream primer: 5'-taatcgatatacccgctc-3' 50μL reaction system: 10×PCR buffer 5μL Tag enzyme 2U/μL 1μL MgCl2 (25mM) 5μL dNTP (2.5MM) 5μL ddH20 29μL Upstream primer 10μM 2μL Upstream primer 10μM 2μL Template DNA 1.5μg/μL 1μL

(4) Product observation: A. Preparation of gel: first prepare agarose solution, heat it to make it fully dissolved, and then add ethidium bromide solution; B. Prepare TAE electrophoresis fluid; C. Pouring gel: pour the prepared agarose solution into the gel plate, wait for it to solidify, and then put it into the electrophoresis tank; D. Electrophoresis: mix the amplified PCR product with buffer in proportion, add it to the gel loading well, add DNA molecular weight standard at the same time, turn on the power, set the voltage and current, and start electrophoresis. E. Observe: observe the amplified product under ultraviolet light and take pictures.

The above is an introduction to the detection method of E. coli in drinking water. Now everyone understands it! In fact, if we do not drink raw water but drink boiled water, there will be no such problems. This is why we are always encouraged to drink cold boiled water. Drinking more cold boiled water is good for your health, no matter you are male, female, young or old.