Beef paste 胨 preparation of a culture base

test 19 beef paste protein
culture
preparation of the base first, the purpose requirements1. Clarify
the
of the culture base.2． Through the preparation ofbeef paste protein, the general methods and steps for the preparation of the culture base are mastered.II, Basic Principles Bus beef paste protein media is one of the most widely used and common bacterial base media, sometimes referred to as ordinary media. It contains beef paste,and NaCl. Among them, beef paste provides carbon

energy for
microorganisms, phosphates, proteins mainly provide nitrogen sources, and NaCl provides inorganic salts. A certain amount of agar is added to the preparation
solid
as a coagulant. Agar melts at a common concentration of 96 degrees C, generally in the boiling water bath or under the pad boiling melt in asbestos mesh, so as not to burn agar. Agar solidifies at 40 degrees C and is usually not used by microbial decomposition. The content of agar in solid mediums varies depending on the quality and temperature of agar.because the medium is mostly used to culture bacteria, pH should be adjusted to neutral or slightly alkaline with thin acid or alkali to help bacteria grow and reproduce.beef paste proteinculture is formulated as follows:beef paste 3gprotein 10g NaCl 5gagar 15-20gwater 1000ml pH 7. 4—7． 6 , equipment beef paste, protein , NaCl, agar; 1mol/L NaOH, 1mol/L HCl;test tube, triangular flavon, beaver, drum, glass rod, medium splitter, torque
balance
, horn spoon, auto-steam sterilization pot, pH
test paper
(pH 5. 5—9． 0), cotton, cow paper, marker pen, hemp rope, gauze, etc., the operation step 1. Weighing the beef paste, protein, protein, and NaCl in the in proportion to the medium formula. Beef paste is often picked with a stick, weighed in a small beech or surface dish, dissolved with hot water and poured into a berries. Can also be placed on the weighing paper, weighing directly into the water, such as a slight
heating
, the beef paste will be separated from the weighing paper, and then immediately remove the pieces of paper. Protein easy to absorb moisture, in the call to move quickly. In addition, when the drug is strictly prevented from mixing, a cow's horn spoon is used for a drug, or take a drug, wash, dry, and then take another drug, bottle cap also do not cover the wrong. 2． Dissolve add less water than needed to the beech, stir well with a glass stick, and then heat it on an asbestos web to dissolve. After the drug is completely dissolved, rehydrate to the desired total volume. If a solid medium is prepared, put the well-known agar into the melted medicine, reheat the melting, in the process of agar melting, need to constantly stir, in order to prevent agar paste bottom to break the beech. Finally, make up for the lost water. 3． PH Before pH is adjusted, the original pH value of the medium is measured with precision pH test paper, if pH is partial to acid, add 1mol/L NaOH to the medium by drop with a dropper, stir side by side, and measure its pH at any time with pH test paper until pH reaches 7. 6。 Conversely, 1mol/L HCl is used to adjust. Note that the pH should not be turned over to avoid a callback, otherwise the concentration of ions in the media will be affected. for some microorganisms that require a more accurate pH, the adjustment of pH can be carried out using an acid meter (using methods, refer to the relevant instructions). 4．
filter Filter with filter paper or multi-layer gauze while hot for observation of the results. In general, this step can be eliminated without special requirements (no filtering is required for this experiment). 5． According to requirements, the preparation of the culture base can be packed into the test tube or triangular cans. The disloading device is shown in Figure V.-1. should not put the culture base on the tube or bottle mouth during the packing process, so as not to contaminate the cotton plug and cause pollution. (1) liquid sub-assembly height to test tube height of about 1/4 is appropriate. (2) solid sub-pack test tube, its loading capacity does not exceed 1/5 of the tube height, sterilized to make a slope, as shown in V.-2. The amount of triangular cans shall not exceed half of the volume of the triangular cans. (3) semi-solid sub-packed test tube is generally suitable for 1/3 of the test tube height, after sterilization vertical to be condensed. 6． After the gasser culture base is installed, a cotton plug is stuffed on the test tube port or triangular besotted port to prevent the outside microorganisms from entering the culture base and cause contamination, and to ensure good breathability (after the cotton stopper production method attached to this experiment). 7． After wrapping plus plugs, tie all the test tubes with hemp rope, and then outsource a layer of psoria in the cotton plug to prevent sterilization when condensate wet cotton plugs, the outside with a hemp rope tied. Indicate the name, group, and date of the culture base with a marker pen. After the triangular flanter is stuffed, outsourced verse paper, with hemp rope in the form of live knots, easy to unwrap when used, the same marker pen to indicate the name of the culture base, group, date. 8． Sterilization the above-mentioned culture base to 1. 05kg/cm
2
(15 lb/inch
2
), 121. 3 degrees C, 20 minutes of steam at high pressure sterilization. If sterilization is not caused by special circumstances, it should be put in the refrigerator for staging. 9． Shelve the slope cool the sterilized test tube culture base to about 50 degrees C, put the test tube cotton plug end on the stick, and the slope length of the shelving should not exceed half the total length of the test tube. 10． Aseptic testing sterilized mediums into a greenhouse at 37 degrees C for 24-48 hours to check that the sterilization is thorough. : the production of cotton the role of cotton plugs have two: first, to prevent miscellaneous contamination; Therefore, the quality of cotton plugs has a great influence on the results of the experiment. The correct cotton plug requires the shape, size, looseness and test tube mouth (or triangular beaker mouth) completely suitable, too tight to prevent air circulation, operation is not convenient; When stuffing, make 1/3 of the length of the cotton plug outside the test tube port, 2/3 inside the test tube port, as shown in Figure V.-3. The process of making cotton plugs is as shown in Figure V.-4. In addition, in microbial experiments and scientific research, it is often common to use breath plugs. The so-called breath plug, is a few layers of gauze (generally 8 layers) overlap each other, or between the two layers of gauze evenly spread a layer of cotton. This breathable plug is usually added to a triangular flanter port filled with a liquid culture base. After inoculation, put on the shaker for oscillating culture, in order to obtain good breath to promote the growth or fermentation of the bacteria. The shape of the air plug is as shown in figure V.-5. , the experimental report the (1) the culture of microorganisms should have what conditions? Why? (2) what problems should I pay attention to during the operation of the preparation of the culture base? Why? Figure V. - 5 Gas plug A. Gauze seze method when preparation;B. Sterilization of psoria; C. Why must the gauze be sterilized after the gauze is turned out and the (3) culture is matched? How do I check that the culture base after sterilization is sterile?