I have a test tomorrow and i need to be able to say what type of bacteria something is in their agar colonies. I am having a hard time diffirentiating between bacillus cereus and bacillus subtilis. does anyone have any good websites that would help? or know any tricks?
When it comes to differentiating between bacteria species such as Bacillus cereus and Bacillus subtilis, there are several methods you can use. Here are some tips to help you:
1. Visual Appearance: Start by observing the colonies' macroscopic (naked eye) characteristics. Note their size, shape, color, and texture. Bacillus cereus colonies are typically round, large, and rough in appearance, while Bacillus subtilis colonies are generally smaller, flatter, and smoother.
2. Gram Staining: Perform a Gram stain to determine the bacteria's Gram reaction. Bacillus cereus is Gram-positive, meaning it will retain the crystal violet stain and appear purple or blue under the microscope. Bacillus subtilis is also Gram-positive.
3. Motility: Test the bacteria for motility. Bacillus subtilis is motile, meaning it possesses flagella and can move, while Bacillus cereus is usually non-motile.
4. Biochemical Tests: Conduct various biochemical tests to identify specific metabolic properties of the bacteria. These tests can include catalase, oxidase, and sugar fermentation tests. A comprehensive microbiology textbook or online resources can provide detailed instructions for performing and interpreting these tests.
To find helpful websites for bacterial identification, consider the following reputable online resources:
1. MicrobeWiki (https://microbewiki.kenyon.edu/): This comprehensive microbiology resource provides information on various bacteria, including Bacillus species.
2. American Society for Microbiology (ASM) (https://www.asm.org/): The ASM website offers a wealth of information on different bacteria, including identification guides and research articles.
3. Centers for Disease Control and Prevention (CDC) (https://www.cdc.gov/): The CDC website contains valuable microbiology resources, including detailed information on specific bacterial species.
4. Medical Microbiology/Textbook Websites: Check out online textbooks or websites dedicated to medical microbiology, as they often cover bacterial identification techniques and provide images for reference.
Remember to cross-reference information from multiple reliable sources to ensure accurate and up-to-date information. Good luck with your test!