Another staining technique for endospores is the Schaeffer-Fulton stain, which stains endospores green and bacterial bodies red. That allows the endospore to show up as red, while the rest of the cell stains blue. To combat this, a special stain technique called a Moeller stain is used. While the rest of a bacterial cell may stain, the endospore is left colorless. Viewing endospores under the light microscope can be difficult due to the impermeability of the endospore wall to dyes and stains. Figure: Endospore morphology: Variations in endospore morphology: (1, 4) central endospore (2, 3, 5) terminal endospore (6) lateral endospore. Bacteria produce a single endospore internally. They are commonly found in soil and water, where they may survive for long periods of time. They are resistant to ultraviolet radiation, desiccation, high temperature, extreme freezing and chemical disinfectants. Endospores can survive without nutrients. The endospore consists of the bacterium’s DNA and part of its cytoplasm, surrounded by a very tough outer coating. Examples of bacteria that can form endospores include Bacillus and Clostridium. When the environment becomes more favorable, the endospore can reactivate itself to the vegetative state. Endospores enable bacteria to lie dormant for extended periods, even centuries. In endospore formation, the bacterium divides within its cell wall. Endospore formation is usually triggered by lack of nutrients, and usually occurs in Gram-positive bacteria. \)ĭescribe the function and advantage of endospore formation, as well as the methods for viewing it.Īn endospore is a dormant, tough, and non-reproductive structure produced by certain bacteria from the Firmicute phylum.
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