lab4
Aseptic Technique and Streak Plates
Purpose
The purpose of this exercise is to learn aseptic technique procedures and there importance and also to learn to isolate colonies using the streak plate technique.
Introduction
Bacteria are inoculated (introduced) and cultured (grown) in the laboratory for test studies to determine their morphology (the shape, size, arrangement, and internal structures) and pathology (ability to cause disease). Inoculation has to be performed without adding other microbes or contaminants. Aseptic (sterile) technique is the process of growing pure (uncontaminated) cultures, and is essential for proper characterization of a bacterium. Aseptic technique includes the use of sterile media and equipment. The sterility of these tools is maintained by proper handling procedure, which prevents the introduction of contamination. The basics of aseptic technique are:
Autoclave or steam sterilization of all equipment and media.
Flame sterilization of wire loops and needles which are used to transfer bacteria from one growth condition to another.
Flaming the mouth of test tubes and other containers to establish hot air convection out of the container, to reduce the chance of microbes entering the tube by air flow.
Mixtures of organisms, as found in nature, will have characteristics of the group and thus identification of a single member of the group is not possible. In order to determine the cause of a disease the microbe must be separated from the mixture and cultured as a pure culture. The standard method of obtaining a pure culture is the streak-plate method on agar.
The streak-plate method is an example of a solid dilution technique. Bacteria are obtained from a mixed culture with a sterile loop or wire and diluted within three sectors on a petri dish containing appropriate growth medium. After incubation, as a result of this dilution technique, individual colonies of microbes can be obtained. Each individual colony represents
Purpose
The purpose of this exercise is to learn aseptic technique procedures and there importance and also to learn to isolate colonies using the streak plate technique.
Introduction
Bacteria are inoculated (introduced) and cultured (grown) in the laboratory for test studies to determine their morphology (the shape, size, arrangement, and internal structures) and pathology (ability to cause disease). Inoculation has to be performed without adding other microbes or contaminants. Aseptic (sterile) technique is the process of growing pure (uncontaminated) cultures, and is essential for proper characterization of a bacterium. Aseptic technique includes the use of sterile media and equipment. The sterility of these tools is maintained by proper handling procedure, which prevents the introduction of contamination. The basics of aseptic technique are:
Autoclave or steam sterilization of all equipment and media.
Flame sterilization of wire loops and needles which are used to transfer bacteria from one growth condition to another.
Flaming the mouth of test tubes and other containers to establish hot air convection out of the container, to reduce the chance of microbes entering the tube by air flow.
Mixtures of organisms, as found in nature, will have characteristics of the group and thus identification of a single member of the group is not possible. In order to determine the cause of a disease the microbe must be separated from the mixture and cultured as a pure culture. The standard method of obtaining a pure culture is the streak-plate method on agar.
The streak-plate method is an example of a solid dilution technique. Bacteria are obtained from a mixed culture with a sterile loop or wire and diluted within three sectors on a petri dish containing appropriate growth medium. After incubation, as a result of this dilution technique, individual colonies of microbes can be obtained. Each individual colony represents