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# The plasmodium is the main vegetative phase of the life cycle. Usually diploid, it is a large syncytium (multiple nuclei in a common cytoplasm) that can grow to very large sizes (under laboratory conditions it can be many centimeters in extent). The plasmodium diagrammed here is in the actively migrating stage, "searching" for additional food. Such plasmodia either cease to migrate when they encounter a fresh source or enter one of two other stages. | # The plasmodium is the main vegetative phase of the life cycle. Usually diploid, it is a large syncytium (multiple nuclei in a common cytoplasm) that can grow to very large sizes (under laboratory conditions it can be many centimeters in extent). The plasmodium diagrammed here is in the actively migrating stage, "searching" for additional food. Such plasmodia either cease to migrate when they encounter a fresh source or enter one of two other stages. | ||
# Under certain conditions of starvation and dessication, plasmodia assume a dormant stage called sclerotia. Properly-prepared and -stored sclerotia can be stored for many years and then reactivated by placing small fragments on a moist food source; a favorite such food (for biologists who study plasmodia) is oatmeal flakes. | ## Under certain conditions of starvation and dessication, plasmodia assume a dormant stage called sclerotia. Properly-prepared and -stored sclerotia can be stored for many years and then reactivated by placing small fragments on a moist food source; a favorite such food (for biologists who study plasmodia) is oatmeal flakes. | ||
# Sporulation, which is an example of cellular differentiation, is induced if starved plasmodia sense visible light, heat shock or other environmental stress (such as flooding, high or low pH, etc.). Cellular commitment to sporulation is followed by the sequential biosynthesis of many new proteins that are required for the formation of fruiting bodies. About eleven hours after induction, the plasmodial mass dissociates into cytoplasmic nodules, each of which culminates to form a fruiting body suspended by a millimeter-sized stalk. The cytoplasmic mass enclosed by the fruiting body divides up into smaller clumps, within which meiotic divisions occur, producing haploid nuclei that become packed as spores. Sporulation is of great practical use for the geneticist since it allows the genetic analysis of all kinds of mutants in Physarum. | # Sporulation, which is an example of cellular differentiation, is induced if starved plasmodia sense visible light, heat shock or other environmental stress (such as flooding, high or low pH, etc.). Cellular commitment to sporulation is followed by the sequential biosynthesis of many new proteins that are required for the formation of fruiting bodies. About eleven hours after induction, the plasmodial mass dissociates into cytoplasmic nodules, each of which culminates to form a fruiting body suspended by a millimeter-sized stalk. The cytoplasmic mass enclosed by the fruiting body divides up into smaller clumps, within which meiotic divisions occur, producing haploid nuclei that become packed as spores. Sporulation is of great practical use for the geneticist since it allows the genetic analysis of all kinds of mutants in Physarum. |
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