Please make an aseptic technique and pure culture technique flowchart Aseptic TechniqueAseptic (or sterile) technique is one of the most critical techniques that any beginning studentin microbiology must learn. This technique ensures that no contaminating microorganisms areintroduced into cultures or culture material and the microbiologist is not contaminated bycultures that are being manipulated. Aseptic technique is crucial in isolating and purifying apure culture and also characterizing an unknown organism. Once an organism is in pureculture and stored as a stock culture, aseptic technique ensures that the culture remains purewhen it is necessary to retrieve the organism.In the procedures below, you will learn techniques that allow you to handle and manipulatemicroorganism cultures. Once you have mastered these procedures, you will be able totransfer microorganisms from one kind of medium to another with confidence. It isimperative that you have a good grasp of these procedures, as they will be required over andover in future experiments throughout this term. With time, these procedures will becomeroutine and second nature to you.To gain some practice in aseptic transfer of bacterial cultures, you will perform severaltransfers of cells in this lab:1. From a broth culture to another broth tube2. From a broth culture to an agar slant3. From a colony on an agar plate to an agar slant4. From a broth culture to a broth tube, both held in the same hand (simulated)5. From a colony on an agar plate to another agar plateThe last type of transfer of cells (involving agar plates) is important not only for keeping culturesuncontaminated, but also for isolating a pure culture from a mixture of multiple different typesof cells. It is thus described further in the following section.A sterile work environment can be maintained in an open work environment, such as the openbench area, or a biological safety cabinet (BSC) can be used. BSCS must be used when workingwith organisms that are designated Level 2 or higher. The principles of aseptic technique apply ineither environment, and you will be exposed to both work environments during this microbiologycourse.Sterile equipment and reagentsAseptic technique requires that all surfaces, equipment, and reagents that may come intocontact with the sample are sterilized or disinfected to avoid contamination. Different sterilizationand disinfection techniques exist depending on the application. The most common techniqueswhen culturing a sample in the lab are listed below. Pure Culture TechniquesWhen we try to study the bacterial flora of the body, soil, water, or just about any environment,we realize that bacteria exist in natural environments as mixed populations. It is only in veryrare instances that they occur as a single species.Pure cultures are required to study the cultural, morphological, and physiologicalcharacteristics of an individual organism. Several methods for obtaining pure cultures areavailable to the microbiologist today. Two commonly used methods arestreak plate methods andpour plate methods.Both types of procedures involve repeatedly diluting the cells in a sample to an end pointwhere a single cell divides giving rise to single pure colony. The colony is therefore assumedto be the identical progeny of the original cell and can be picked and used for further study ofthe bacterium.StreakingOne drop of bacterial solution contains millions of cells. To identify a species, individual strainshave to be grown separately, starting from a single cell. The most commonly used method toisolate strain originating from a single cell is called the streaking method. There are severaldifferent ways to streak a plate.Figure 1: Streaking pattern on the agar plate. The colored lines indicate the path of the wire loop.Streaking methods all follow the same basic principle: a large number of cells are spread over thesurface of an agar plate in a sequential fashion until the cells are spread far apart from oneanother. The numbers and colors refer to the order of the streaks. For example, streak numbertwo is started by placing a sterile loop inside streak number one to pick up bacteria.Following streaking, the plate is incubated and the cells start to divide and form colonies. Singlecells will form colonies of genetically identical clones. Isolated colonies usually grow larger thancolonies situated closely together due to less competition for nutrients. These isolated coloniescan be used to make a pure culture, a liquid or solid culture in which all bacteria are geneticallyidentical, for further study. In some cases, the motility or morphology of the colony can alsoprovide useful information for identification.Colony MorphologiesWhen observing colonies on plates, it is important to consider the opacity of the colonies. Thereare three opacity descriptors: transparent, translucent, opaque.You can also note whether the colonies are "smooth (shiny glistening surface), rough (dull,bumpy, granular, or matte surface), or mucoid (slimy or gummy appearance)."It is also important to note colony morphology as this can aid in identification of the microbe.Typical descriptors of colony morphology are shown in the figure below.

The aseptic technique is a fundamental practice in microbiology aimed at preventing the introduction…

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11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...