. Outline the steps involved in an endospore stain (remember smear prep is a par
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. Outline the steps involved in an endospore stain (remember smear prep is a part of or the Gram stain, what reagents act as the primary which reagents act as the primary stain and counterstain. Understand why endospores ar 8. Why is a dilution series often done before making colony counts? (think along the ines of number why endospores are diffcuit to stain organisms and what you would see on the plate) 9. Be able to recognize a proper streak for isolatio 10. What is the Kirby-Bauer Disk Diffusion Method? What is meant by a "Zone of r plate, be able to measure this. For what reason(s) migh antimicrobial show no zone of inhibition? n and know the purpose of performing this procedure t a chemical that is usually thought to be a good 11. How would you test for the ability of a microbe to produce catalase? 12. What medium is used to test for hemolysis? Why is this an important test in a clinical lab? 13. Be able to identify the following on microscope slides: Gram positive bacteria, Gram negative bactenia. the three basic shapes of bacteria, endospores, negative stain amecium, sample is viewed to " Handout to view these organisms OR you 14. Be able to identify the following on microscope slides: Aspergillus, Penicillium, Euglena, Oscillatoria, Trypanosoma. For the last genus in this list, what type diagnose the infection? Use the "Survey of Microorganisms can view the actual slides on a microscope in the ACE Center (SSB 2201). 15. Know what bacteriophage and viral plaques are; Know howl/why they are related:, Understand why bacteriophage must be grown in bacteria 16. Understand what a plasmid is, and be able to briefly explain how it can be inserted into a bacterium. Know what this process is called. 17. Why can't bacteria be stained using acidic dyes? What are basic dyes? Be able to explain the general concept in terms of the use of these types of dyes on bacteria. Yes we discussed this! 18. Understand how UV light affects bacterial cells and bacterial endospores. 19. Understand the significance of biochemical tests in the identfication of microorganisms 20. Be able to identify an organism using a dichotomous key or a version of the chart you have been using to determine your unknown organisms. 21. Be familiar with the GENERAL lab safety rules. If you follow them, then this should be easy letures posted on CanvasExplanation / Answer
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Ans:
The steps involved in an endospore stain:
- Endospores are very resistant structures made by only few genera of bacteria.
- The endospore stain is a differential stain which selectively stains bacterial endospore.
- Prepare a smear of endospore producing organism, allow the smear to dry and then heat fix.
- The primary stain applied is malachite green which stains both vegetative cells and endospores.
- Heat is applied to help the primary stain penetrate the endospore.
- The cells are then decolorized with water, which removes the malachite green from the vegetative cells but not the endospore.
- Safranin is then applied to counterstain cells which have been decolorized .
- At the end of the staining process, vegetative cells will be pink and endospores will be dark green.
- Spores have a tough outer covering made of keratin and are highly resistant to heat, chemicals and staining. Hence, endospores are difficult to stain.
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