Example 1. The following spreadsheet uses the Excel Char function to return the character associated with different supplied character set numbers. Note that these results are from the Ansi character set (used on the Windows operating system).
Potassium tellurite agar is selective for the growth of Staphylococci and is somewhat selective for the growth of Corynebacteria. Staphylococci and Corynebacteria reduce the potassium tellurite in the agar, which makes the colonies grow black.
MacConkey agar is a selective medium containing bile salts and crystal violet that inhibits the growth of Gram-positive bacteria while allowing for the growth of Gram-negative bacteria.MacConkey agar is often used when investigating and culturing fecal bacteria.he MacConkey agar we talked about as an example of a selective media is also a differential media. In addition to the selective bile salts and crystal violet, MacConkey agar contains a pH indicator and the sugar lactose.