ENDOMIXIS IN PARAMECIUM
It occurs in P. aurellia which has two micronuclei and one macronucleus. During the process of endomixis, macronucleus disappear by by degeneration, and the micronuclei divide twice to form eight micronuclei. A transverse constriction, horizonal to the longitudinal body axis divides the animal into two each having four daughter micronuclei. In each half, three micronuclei degenerate, and the remaining micronuclei of each daughter cell divides twice to form four nuclei, two of which become the micronuclei and two macronuclei. The remaining two micronuclei again divide automatically resulting into four micronuclei. Now each cell again divides, each daughter individual has now one macro and two micronuclei. New contractile vacuoles and ingestatory apparatus develop in each daughter paramecia. Thus, from one organism, four daughter paramecia are formed.
Endomixis is of high significance. It is actually the phenomenon of nuclear reorganisation followed by the division of body with in a singal individual, with no nuclear exchange or fusion. As a result of endomixis, four daughter paramecia are formed from a singal parent, thus it is a mode of multiplication. It serves as a substitute for conjugation as reorganization and readjustment of the nuclear material and cytoplasm during endomixis result in to rejuvenescence.
Paramecium, stages in endomixis.
HEMIXIS
It is a simple phenomenon of nuclear reorganisation found in P. aurellia. In the process, the micronuclei remain inert and the meganucleus separate off several minute chromatin part which are abscribed in the surrounding of cytoplasm. The micro and meganuclei then behave normally and divide by usual manner. Hemixis is believed to be an act by which the macronucleus is purified.
Paramecium, stage in hemixis.
It occurs in P. aurellia which has two micronuclei and one macronucleus. During the process of endomixis, macronucleus disappear by by degeneration, and the micronuclei divide twice to form eight micronuclei. A transverse constriction, horizonal to the longitudinal body axis divides the animal into two each having four daughter micronuclei. In each half, three micronuclei degenerate, and the remaining micronuclei of each daughter cell divides twice to form four nuclei, two of which become the micronuclei and two macronuclei. The remaining two micronuclei again divide automatically resulting into four micronuclei. Now each cell again divides, each daughter individual has now one macro and two micronuclei. New contractile vacuoles and ingestatory apparatus develop in each daughter paramecia. Thus, from one organism, four daughter paramecia are formed.
Endomixis is of high significance. It is actually the phenomenon of nuclear reorganisation followed by the division of body with in a singal individual, with no nuclear exchange or fusion. As a result of endomixis, four daughter paramecia are formed from a singal parent, thus it is a mode of multiplication. It serves as a substitute for conjugation as reorganization and readjustment of the nuclear material and cytoplasm during endomixis result in to rejuvenescence.Paramecium, stages in endomixis.
HEMIXIS It is a simple phenomenon of nuclear reorganisation found in P. aurellia. In the process, the micronuclei remain inert and the meganucleus separate off several minute chromatin part which are abscribed in the surrounding of cytoplasm. The micro and meganuclei then behave normally and divide by usual manner. Hemixis is believed to be an act by which the macronucleus is purified.
Paramecium, stage in hemixis.
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