Bacteria
Bacterial Smears Are Fixed before Staining to?
Answer
It is important to heat fix the bacterial smear before staining so as to, kill the bacteria, firmly adhere the smear on to the microscopic slide to prevent washing off during staining, and to allow the sample to readily take up the stain.
Reference:
www2.hendrix.edu
What is the purpose of heat- fixing the smear?
It helps the cells adhere to the slide so that they can be stained.
The purpose of heat fixing is to kill the organisms without serious distortion. They adhere better to the slide and also take up dye more easily.
Fixation process
Fixation is usually the first stage in a multistep process to prepare a sample of biological material for microscopy or other analysis. Therefore, the choice of fixative and fixation protocol may depend on the additional processing steps and final analyses that are planned. For example, immunohistochemistry uses antibodies that bind to a specific protein target. Prolonged fixation can chemically mask these targets and prevent antibody binding. In these cases, a 'quick fix' method using cold formalinfor around 24 hours is typically used. |
Types of fixation
There are generally three types of fixation process:
Heat fixation: After a smear has dried at room temperature, the slide is gripped by tongs or a clothespin and passed through the flame of a Bunsen burner several times to heat-kill and adhere the organism to the slide. Routinely used with bacteria and archaea. Heat fixation generally preserves overall morphology but not internal structures. Heat denatures the proteolytic enzyme and prevent autolysis. Heat fixation cannot be used in the capsular stain method as heat fixation will shrink or destroy the capsule (glycocalyx) and cannot be seen in stains.
Perfusion: Fixation via blood flow. The fixative is injected into the heart with the injection volume matching cardiac output. The fixative spreads through the entire body, and the tissue doesn't die until it
Answer
It is important to heat fix the bacterial smear before staining so as to, kill the bacteria, firmly adhere the smear on to the microscopic slide to prevent washing off during staining, and to allow the sample to readily take up the stain.
Reference:
www2.hendrix.edu
What is the purpose of heat- fixing the smear?
It helps the cells adhere to the slide so that they can be stained.
The purpose of heat fixing is to kill the organisms without serious distortion. They adhere better to the slide and also take up dye more easily.
Fixation process
Fixation is usually the first stage in a multistep process to prepare a sample of biological material for microscopy or other analysis. Therefore, the choice of fixative and fixation protocol may depend on the additional processing steps and final analyses that are planned. For example, immunohistochemistry uses antibodies that bind to a specific protein target. Prolonged fixation can chemically mask these targets and prevent antibody binding. In these cases, a 'quick fix' method using cold formalinfor around 24 hours is typically used. |
Types of fixation
There are generally three types of fixation process:
Heat fixation: After a smear has dried at room temperature, the slide is gripped by tongs or a clothespin and passed through the flame of a Bunsen burner several times to heat-kill and adhere the organism to the slide. Routinely used with bacteria and archaea. Heat fixation generally preserves overall morphology but not internal structures. Heat denatures the proteolytic enzyme and prevent autolysis. Heat fixation cannot be used in the capsular stain method as heat fixation will shrink or destroy the capsule (glycocalyx) and cannot be seen in stains.
Perfusion: Fixation via blood flow. The fixative is injected into the heart with the injection volume matching cardiac output. The fixative spreads through the entire body, and the tissue doesn't die until it