Lab Manual- Benson\'s Microbiology Applications 14e Exercise 16- Spore Staining
ID: 198303 • Letter: L
Question
Lab Manual- Benson's Microbiology Applications 14e Exercise 16- Spore Staining (5pts) Read p 119- 120 and answer the following questions 1. What two genera of bacteria form endospores when they exhaust essential nutrients 2. Give 3 differences between a vegetative cell and an endospore (based on lab manual p119) 3. What dyes can be used to stain the endospore? 4. What method is used to destroy endospores? 5. What is the difference between the Schaeffer method and the Dorner method of staining endosporesExplanation / Answer
1) There are several genera of bacteria that produce endospores when they exhaust nutrients, including Desulfotomaculum, Sporosarcina, Sporolactobacillus, Oscillospira, and Thermoactinomyces.
2) A) Vegetative cells are normally gram positive cells, and a few gram negative cells. Endospores are thick spore cortex with spore coat exospores.
B) Microscopic appearance of vegetative cells is nonrefractile while endospores are refractile.
C) Calcium content is low and dipicolinic acid is absent in vegetative cells while calcium content is high and dipicolinic acid is present in endospores.
3) Malachite green is used to stain the endospores.
4) Endospores can be destroyed by autoclaving at a temperature of 100 °C. The longer the number of hours of autoclaving the fewer endospores will survive.
5) In Schaeffer-Dulton Technique, malachite green 0.5% is used for primary staining, and Safranin (2.5%) is used for counter staining.
In Dorner's Method, carbolfuchsin stain is used for primary staing, acid-alcohol is used for decolorization, and counterstain nigrosin solution is used.
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