Beef extract peptone agar medium This is a very widely used natural medium. The beef extract provides carbon sources, phosphates and vitamins for microorganisms, peptone mainly provides nitrogen sources and vitamins, and NaCl provides inorganic salts. Specific preparation steps: 1. Weighing: Weigh the beef extract, peptone, and NaCl in the beaker according to the proportion of the medium formula. Beef paste is usually picked with a glass rod, weighed in a small beaker or watch glass, dissolved in hot water and poured into the beaker. It can also be placed on the weighing paper, and directly put into water after weighing. At this time, if it is heated slightly, the beef paste will be separated from the weighing paper, and then the paper sheet is immediately removed. Peptone is very hygroscopic and moves quickly when weighing. In addition, when mixing medicines, it is necessary to prevent the mixing of medicines. A horn spoon is used for a medicine, or after taking a medicine, wash and dry it, and then weigh another medicine. Do not put the bottle cap on the wrong one. 2. Dissolve: Add less than the required amount of water to the above-mentioned beaker, stir well with a glass rod, and then heat on the asbestos mesh to dissolve. After the drug is completely dissolved, add water to the total volume required. If a solid medium is prepared, put the weighed agar into the dissolved medicine, and then heat to dissolve it. During the process of the agar dissolving, stirring is needed to prevent the agar paste from breaking the beaker. Finally make up the lost water. 3. Adjust the pH: Before adjusting the pH, first measure the original pH value of the culture medium with precision pH test paper. If the pH is acidic, add 1mol / L NaOH to the culture medium dropwise with a dropper, stirring while adding, and Measure the pH value with pH test paper at any time until the pH reaches 7.6. Otherwise, use 1mol / L HCl for adjustment. Note that the pH value should not be adjusted too far to avoid callback, otherwise, it will affect the concentration of ions in the medium. For some microorganisms that require a more precise pH value, the pH can be adjusted with an acid meter (for usage, please refer to the relevant instructions). 4. Filtration: While hot, filter with filter paper or multi-layer gauze to facilitate the observation of results. If there are no special requirements, this step can be omitted (no filtering is needed in this experiment). 5. Packing: According to the experimental requirements, the prepared medium can be packed into test tubes or conical flasks. 6. Stoppering: After the medium is filled, put a cotton stopper on the mouth of the test tube or triangular flask to prevent outside microorganisms from entering the culture medium and causing pollution, and to ensure a good aeration performance Behind). 7. Bandage: After plugging, all the test tubes are tied up with hemp rope, and then a layer of kraft paper is wrapped on the tampon to prevent the condensed water from wetting during sterilization. Use a marker to indicate the medium name, group, and date. After the stopper is filled with kraft paper, it is wrapped with hemp rope in the form of a loose knot. It is easy to untie it when using it. Also use a marker to indicate the medium name, group and date. Freestanding DIY Patio Clamp Awning Freestanding Diy Patio Clamp Awning,Diy Freestanding Awning,Freestanding Awning For Patio, Diy Patio Awning Hebei Charlotte Enterprise Co., Ltd. , https://www.clshadesails.com