Question

Most colonies on streak plates grow from isolated colony-forming units. on rare occasions, however, a colony can be a mixture of two different organisms. if a culture is started from this colony (thinking it's pure), correct identification will be next to impossible because the extra organism could confound the identifying test results. how could you verify the purity of a colony? if you found the colony to be a mixture of organisms, what could you do to purify it?

Answer 1

To verify the purity of a colony, a number of steps could be adopted. Pick the colony and dissolve it in sterile water (approximately 5ml), streak in media again and incubate. Observe if it produces pure colonies of the chosen organisms and if not, repeat the procedure until pure colonies are produced. Additionally, one could perform additional tests that categorize bacteria such as Gram staining.   

Answer 2

Answer:

A mixture of colonies can be discovered simply after performing the gram staining process. Before that the settlement qualities like edges, height, shading and appearance can be seen with the unaided eye via cautiously watching the streaked plates. During the recoloring procedure the province utilized for smear planning must be checked. At least two distinct smears are set up from the blended culture. After the recoloring technique, the smear must be deliberately watched for the settlement morphology (bacilli or cocci or streptococci or staphylococci or diplococi and so on). The shade of appearance (purple or pink) must be seen to recognize whether the spread culture contains gram positive or gram negative microscopic organisms. When The given culture was found as gram positive or negative, at that point biochemical qualities are contemplated. These incorporate a wide assortment of tests like maturation of various sugars, IMVIC tests, H2S decrease, catalyses and Oxidase tests, Growth at various temperatures, pH and salt focuses; Nitrate decrease gelatin liquefaction and anti-microbial affect-ability tests. At long last, the outcomes watched are contrasted and the qualities given in Bergy's manual to acquire a thought regarding the living beings present in the blended culture. Further, they can be affirmed through 16SrDNA sequencing to especially think about which species is available in the way of life.