Please make an aseptic technique and pure culture technique flowchart
Extracted text: Aseptic Technique Aseptic (or sterile) technique is one of the most critical techniques that any beginning student in microbiology must learn. This technique ensures that no contaminating microorganisms are introduced into cultures or culture material and the microbiologist is not contaminated by cultures that are being manipulated. Aseptic technique is crucial in isolating and purifying a pure culture and also characterizing an unknown organism. Once an organism is in pure culture and stored as a stock culture, aseptic technique ensures that the culture remains pure when it is necessary to retrieve the organism. In the procedures below, you will learn techniques that allow you to handle and manipulate microorganism cultures. Once you have mastered these procedures, you will be able to transfer microorganisms from one kind of medium to another with confidence. It is imperative that you have a good grasp of these procedures, as they will be required over and over in future experiments throughout this term. With time, these procedures will become routine and second nature to you. To gain some practice in aseptic transfer of bacterial cultures, you will perform several transfers of cells in this lab: 1. From a broth culture to another broth tube 2. From a broth culture to an agar slant 3. From a colony on an agar plate to an agar slant 4. 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 plate The last type of transfer of cells (involving agar plates) is important not only for keeping cultures uncontaminated, but also for isolating a pure culture from a mixture of multiple different types of 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 open bench area, or a biological safety cabinet (BSC) can be used. BSCS must be used when working with organisms that are designated Level 2 or higher. The principles of aseptic technique apply in either environment, and you will be exposed to both work environments during this microbiology course. Sterile equipment and reagents Aseptic technique requires that all surfaces, equipment, and reagents that may come into contact with the sample are sterilized or disinfected to avoid contamination. Different sterilization and disinfection techniques exist depending on the application. The most common techniques when culturing a sample in the lab are listed below.
Extracted text: Pure Culture Techniques When 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 very rare instances that they occur as a single species. Pure cultures are required to study the cultural, morphological, and physiological characteristics of an individual organism. Several methods for obtaining pure cultures are available to the microbiologist today. Two commonly used methods are streak plate methods and pour plate methods. Both types of procedures involve repeatedly diluting the cells in a sample to an end point where a single cell divides giving rise to single pure colony. The colony is therefore assumed to be the identical progeny of the original cell and can be picked and used for further study of the bacterium. Streaking One drop of bacterial solution contains millions of cells. To identify a species, individual strains have to be grown separately, starting from a single cell. The most commonly used method to isolate strain originating from a single cell is called the streaking method. There are several different 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 the surface of an agar plate in a sequential fashion until the cells are spread far apart from one another. The numbers and colors refer to the order of the streaks. For example, streak number two 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. Single cells will form colonies of genetically identical clones. Isolated colonies usually grow larger than colonies situated closely together due to less competition for nutrients. These isolated colonies can be used to make a pure culture, a liquid or solid culture in which all bacteria are genetically identical, for further study. In some cases, the motility or morphology of the colony can also provide useful information for identification. Colony Morphologies When observing colonies on plates, it is important to consider the opacity of the colonies. There are 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.