Heat resistance of endospores of Bacillus pumilus Abstract Spore suspension of Bacillus pumilus was inoculated into universal bottles containing sterile distilled water in water baths at temperatures of 85°C‚ 90°C and 95°C. At specific time intervals‚ a sample was removed and spread on nutrient agar plates. The number of colonies formed was used to determine the D-value and z-value. The D-value for 85°C is 64.1 minutes‚ 25.7 minutes for 90°C and 8.2 minutes for 95°C while the z-value is 11
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can you determine the intracellular location of the spore? Can this also used for taxanomic purposes? When viewed unstained‚ endospores of living bacilli appear edged in black and are very bright and refractile. Endospores strongly resist application of simple stains or dyes and hence appear as nonstaining entities in Gram-stain preparations. However‚ once stained‚ endospores are quite resistant to decolorization. This is the basis of several spore stains such as the Schaeffer-Fulton staining method
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Bacillus Cereus Bacillus cereus is a rod-shaped gram- positive bacillus that can be found in food‚ dust‚ dirt and sometimes soil. It is an aerobe and a facultative anaerobe that can form spores‚ which if activated at any point can begin to germinate and produce toxins. These spores that form from B. cereus are be resistant to heat and chemicals. B. cereus is found in approximately 25% of food sampled (3). Foods that are commonly associated with B. cereus are potatoes‚ rice‚ meat‚ vegetables
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Exercise 3.9 Endospore Stain (Differential Stain) Eula Lewis Bio 2921 February 27‚ 2013 Zere Ezaz‚ Ph. D. Objective: 1. To learn to endospore stain 1. To distinguish endospores‚ free spore‚ and vegetative cells Theory: A dormant form of bacterium that allows it to survive poor environmental conditions are called endospores. Their tough outer covering is made of keratin and is also the reason they are resistant to heat and chemicals. The strength of keratin also makes it resist
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Endospore and Capsule Cell Staining Allison Lui Partner: Mary Chagin BIOL-235 W07 Dr. Runco 2/10/15 Introduction The purpose of this lab is to learn what endospore and capsules are‚ and how to identify them under a microscope using capsule and endospore staining methods. Capsules are found only in select bacteria‚ and serve a protective purpose. Made out of sugars and proteins‚ they are antiphagocytic‚ which prevents other cells to engulf the bacteria through phagocytosis. It
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cell wall. The dye will be locked in the spore wall‚ which has peptidoglycan deeper in the walls. The keratin forming the outer portion of the endospore wall resists dye. The heating of the bacteria will make the spore wall more permeable to the malachite green‚ and it then attaches to the peptidoglycan. Thus‚ we can detect the bacteria that have the endospore based on this test. On a clean glass slide a drop of distilled water will be added to the slide. A smear will be prepared on this droplet by
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sizes‚ shapes and arrangements of microorganisms. -Gram stain assists in identifying the type of microbes‚ whether they are gram positive or negative‚ which in turn tells us what kind of cell wall the microbes have. -Endospore stain tells whether microorganisms make endospores. -Acid-fast stain is helpful in recognizing the existence of mycolic acid in cell walls. -Capsule stain reveals the existence of capsules. Methods: Simple Stain For this experiment‚ I used E. coli to make
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soil and/or water where it can lie dormant until contact with host. Portal of entry can be from a cut‚ inhaled‚ ingested or a biological vector. An open wound is always susceptible to infection. Being in an environment where there is potential for endospores can lead to open lesions and necrosis of surrounding skin. Livestock‚ feed lots‚ and processing plants of animals and feed‚ are the areas of most concern and the source of the infection.
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allows in distinguishing the microorganism from its backgrounds. Also‚ helps in studying different internal structures such as vacuoles‚ cell walls and spores in details (Seeley and others 1991). Some staining techniques such as Gram staining‚ endospore stain and capsule stain are some of the theories of stains used in bacteriology today. Also‚ these staining procedures help in determining properties of an unknown culture. Gram staining is a differential stain that helps in distinguishing between
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Explain why endospores are capable of surviving for a very long time. An endospore is a structure that allows certain bacterial species to be able to survive during adverse conditions. Endospores can withstand extremes in heat‚ drying‚ freezing‚ radiation and chemicals that would kill most other cells. Their survival is due to their ability to be heat resistant is due to a high content of calcium and dipicolinic acid. These compounds remove water and leave the cell dehydrated. Endospores also have
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