the vegetative cells that contain endospores should stain pink while the spores should be seen as green ellipses within the cells. Mature, free endospores should not be associated with the vegetative bacteria and should be seen as green ellipses.
Cell staining is a technique that can be used to better visualize cells and cell components under a microscope. By using different stains, one can preferentially stain certain cell components, such as a nucleus or a cell wall, or the entire cell.
Types of staining techniques. Simple staining. Differential staining. (Use of of single stain ) (Use of two contrasting stains ) Direct. Indirect. Separation. Visualization. (Positive) (Negative) into groups. of structures. Gram stain. Flagella stain. Acid fast. Capsule stain.
How could an endospore stain be used to separate the two indistinguishable species? The endospore stain includes lots of heating, which would destroy the cells, but not the endospore, so the only stain would appear on the endospore. This would be used to differentiate between the species.
Endospores enable bacteria to lie dormant for extended periods, even centuries. There are many reports of spores remaining viable over 10,000 years, and revival of spores millions of years old has been claimed.
When viewed unstained, endospores of living bacilli appear edged in black and are very bright and refractile. Endospores strongly resist application of simple stains or dyes and hence appear as nonstaining entities in Gram-stain preparations. However, once stained, endospores are quite resistant to decolorization.
Most Popular Microscopy Techniques
|Common acronym||Full name|
|LSFM||Light Sheet Fluorescence Microscopy|
|PALM||Photoactivated Localization Microscopy|
|SDCLM||Spinning Disk Confocal Laser Microscopy|
|SEM||Scanning Electron Microscopy|
A bacterial smear is a thin layer of bacteria placed on a slide for staining.
Hans Christian Gram developed the staining method in 1884. The staining method uses crystal violet dye, which is retained by the thick peptidoglycan cell wall found in gram-positive organisms. This reaction gives gram-positive organisms a blue color when viewed under a microscope.
There are three broad categories of biological stains: General or Routine Stains: Used to differentiate between the nucleus and the cytoplasm. Special Stains: These are used to demonstrate specific elements within the tissue, such as connective tissue, muscle, carbohydrates, lipids, pigments, and nerve tissue.
For light microscopy, three techniques can be used: the paraffin technique, frozen sections, and semithin sections. The paraffin technique is the most commonly used. Once the sections are prepared, they are usually stained, to help distinguish the components of the tissue.
Basic stains, such as methylene blue, Gram safranin, or Gram crystal violet are useful for staining most bacteria.
Bacterial spores are extremely durable and can be very difficult to destroy even under extreme temperatures. Bacterial spores can survive drought, extreme temperatures, and low pH. Once favorable conditions return, the protective proteins dissolve the spore coating and the vegetative cell functions resume.
It allows the bacterium to produce a dormant and highly resistant cell to preserve the cell’s genetic material in times of extreme stress. Endospores can survive environmental assaults that would normally kill the bacterium.
Because of their tough protein coats made of keratin, spores are highly resistant to normal staining procedures. The primary stain in the endospore stain procedure, malachite green, is driven into the cells with heat.