ost b the acterial ISOLATION BY STREAK PLATE METHOD refo in order to One same st
ID: 226867 • Letter: O
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ost b the acterial ISOLATION BY STREAK PLATE METHOD refo in order to One same study the characteristics habitats composed of mixed populations of organisms species, since The of individual technique they are "pure as used implies species single that may derived from one cel that all organisms in culture are of nvolve be used to obtain such the isolated colonies a sample res the streak plate method of This individual after appropriate from is culture onto an agar plate in order to obtain arise due to a mixed colonies may us The of or axenic then implies that the then be used to divisions of a single 2 Nutrient Agar onto new media for further study and characterization. Pour cell (colony forming Tubes 3 Sterile Agar Dishes Nutrient Broth cultures and Cultures of: Sarcina ixe Broth Serratia marcescens Red rocedure: 1. Each student melt, cool in constant temperature bath, and pour 3 nutrient plates. 2. Allow plates to cool and solidify 3. the NA cultures listed above and streak 1 plate for isolation as demonstrated. Flame the loop between each set of streaks and 4. Streak agar before continuing streaking. cool it by touching to the organism second NA plate for (See diagram on next culture of the same you selected using the Nutrient Broth for Step 3 5. Label well and place inverted plates in the incubator for incubation. ults: After appropriate incubation, observe the plates for small, well isolated individual colonies. Describe the colonial morphology (not cellular morpholog) of the 2 organisms Sarcina Serratia marcescens tod hapud Sued Aassebi Practice "picking up" a small isolated colony with your loop or needle. Prepare gram stains of the new organisms used. Compare the number of isolated colonies on the plate streaked with the slant culture versus the plate streaked with the broth culture. How mightyou improve your results? 30Explanation / Answer
1. the colonies derived from single cell or cfu should be genetically pure in laboratory conditions. since the experiments are done in sterile conditions without any mutagenic agents, the colonies should be pure. however, subculturing for a long time may induce genetic variations.
2. small isolated colony is preferred over large colony because small colony contains relatively a fewer number of cells. therefore streaking from a small colony gives single colonies as well as pure cuultures.
4. since we need to confirm immediately, microscopy is the best tool. we can observe the cells under microscope. if all the cells are similar in shape and size, we can confirm it is a pure culture.
otherwise, we can streak onto an agar plate to observe the colony morphology.
5. when streaking from broth: the inovulation loop must be sterilised by heating it in flame until it turns red. then hold the conical flask containing culture near to flame. heat the neck or opening of flask lightly. then immerse the loop into culture. heat the agar containing petriplate a little bit for 2-3 seconds. then streak onto the plate. the streaking should be done near the flame.
when streaking from slant: hold the slant containing tube near to flame. take a very small amount of microorganism with the help of loop and then streak onto plate near the flame.
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