Culture characteristics of microorganism in experiment 26

1、 Basic principles the culture characteristics of microorganisms refer to the colony morphology and growth of microorganisms on the culture medium Generally, slant, liquid and semi-solid media can be used to test the culture characteristics of different microorganisms They can be cultured on slant medium in the form of filaments, bristles, beads, sparsely spread, branches or pseudoroots (Fig Ⅶ - 6) Growing in liquid medium, it can be turbid, flocculent, mucilaginous, forming bacterial membrane, with clear upper layer and precipitate bottom In semi-solid medium, puncture culture can spread around the inoculation line, or only grow along the line, or grow well in the upper layer, or even in one piece, with little growth at the bottom, or grow well in the bottom, or even not in the upper layer The characteristics of microorganism culture can be used as a reference for species identification and identification of pure culture When testing the culture characteristics of microorganisms or conducting other microbiological experiments, the inoculation process must be guaranteed not to be polluted by other microorganisms Therefore, in addition to the requirements of the working environment to avoid or reduce the contamination of miscellaneous bacteria as much as possible, it is very important to master various aseptic operation inoculation techniques skillfully 2、 Equipment: Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Geotrichum candidum, Bacillus mycoides, Serratia marcescens; Meat extract peptone slant culture medium, meat extract peptone liquid culture medium, semi-solid meat extract peptone culture medium, inoculation ring, inoculation needle, sterile straw, alcohol lamp, etc 3、 Operation step 1 Slant inoculation (1) on the slant interview tube of meat extract peptone, write the name, date and inoculant of the inoculated bacteria with a marker pen (2) Light the alcohol lamp or gas lamp (3) Hold the culture test tube and the inclined test tube to be inoculated in the left hand with the thumb, index finger, middle finger and ring finger, and clamp the middle finger between the two test tubes to make the inclined surface upward and horizontal, as shown in figure vii-7 Loosen the tube plug with the right hand at the flame side to facilitate pulling out during inoculation (4) Take the inoculation ring in the right hand and sterilize it with flame (refer to experiment 1) Hold the cotton plug (or test tube cap) with the palm edge and small finger of the right hand, small finger and ring finger respectively at the flame edge, take it out and burn the nozzle quickly (5) Put the sterilized inoculation ring into the test tube of bacteria, contact the ring with the inner wall of the test tube or the culture medium without bacteria to achieve the purpose of cooling, and then pick up a few bacterial moss Pull the inoculation ring out of the culture tube, and quickly extend it into the inclined tube to be inoculated Use the ring to draw a line gently from the bottom of the tube to the upper end of the inclined tube Do not cut the culture medium, and do not make the ring contact the tube wall or nozzle (6) The inoculation ring exits the inclined tube, then burns the nozzle with flame, and plugs the tube at the flame side Bring the inoculation ring closer to the flame, and then burn it If there are many bacteria on the inoculation ring, the ring should be dried at the edge of the flame, and then burned to prevent the unburned bacteria from splashing out to pollute the environment Pay more attention to this point when inoculating the pathogenic bacteria 2 Liquid medium inoculation When inoculating a small amount of bacteria into the liquid medium of peptone of meat extract, the operation steps are basically the same as that of slanting inoculation The difference is that after the inoculation ring of bacteria is put into the liquid medium, it should be slightly rubbed on the inner wall of the tube at the liquid surface to make the bacteria fall off from the ring, mix into the liquid medium, plug the tube plug, shake the liquid to make the bacteria distributed in the liquid Mix well, or mix well with a tube oscillator, as shown in figure Ⅶ - 8 When the amount of inoculation to the liquid medium is large or the quantitative inoculation is required, the sterile water or liquid medium can be injected into the culture tube, the coating can be scraped off with the inoculation ring, and then the culture suspension can be quantitatively sucked out and added with the sterile straw, or directly poured into the liquid culture medium If the strain is liquid culture, it can be added or directly poured into the liquid culture medium by quantitative suction with sterile pipette Aseptic operation is required in the whole inoculation process 3 For puncture inoculation, the inoculant needle shall be used to pick up the strain (the needle must be straight), and the inoculant needle shall be vertically inserted into the semi-solid medium from the center of the medium until it is close to the bottom of the tube, but it shall not be penetrated Then, pull out the needle along the original puncture line, plug the tube plug, and burn the inoculant needle, as shown in figure vii-9 The aseptic operation of the above-mentioned inoculation methods, if not mentioned, shall be carried out according to experiment one The experimenter should practice the aseptic operation inoculation technology repeatedly until he is proficient in it 4 Put the inoculated slant, liquid and semi-solid medium in a 28-30 ℃ incubator, and take out the observation results after 2-3 days 4、 Experiment report