Wednesday, 13 May 2015

Desmids, beauties in microscopy

This photomicrograph shows Micrasterias fimbriata, a type of green alga called a desmid. Micrasterias fimbriata belongs to one of the rare desmids of the Lowlands. This one was recently found in a fen in the north of Belgium. Micrasterias is named from the Greek mikros, "small" plus aster, "star".

Desmids usually inhabit the acidic waters associated with sphagnum (peat) bogs. These particular desmids are flat, plate-like single cells made up of
two halves (semicells), which are mirror images of each other with highly ornamented edges. The two semicells are joined by a narrow central bridge, or isthmus, containing the nucleus where the organism's genetic material is held.

Micrasterias sp. can reproduce asexually by binary fission (resulting in two separate cells, each of which has one of the parent's semi cells and one new semicell). During this process, genetic material is duplicated and two new semi cells grow between the original semi cells. Micrasterias can also reproduce sexually through a process known as conjugation, which involves the transfer of genetic material between two cells.

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