Wednesday, July 30, 2008

If you have a sample that you cannot see under the microscope such as a cell; it is because most cells appear transparent under the microscope. Stains are used to illuminate certain parts of a specimen under a slide. They can also be used to expose certain parts of a specimen on a slide. Gram's stain is a widely used method of staining bacteria as an aid to their identification. The Gram Stain was created by Hans Christian Joachim Gram, a Danish bacteriologist in 1844. Gram's method of stain was crystal violet. The microorganisms that retain the crystal violet iodine under the microscope appear purple brown in color. Gram's method of staining is categorized as gram positive or gram non-negative. Other microorganisms that are not stained by crystal violet are categorized as gram negative. Staining techniques are useful in distinguishing the presence or nonexistence of certain cell components. What this does is allow the lab technician to make a distinction or identification of microorganisms.