How do protozoa osmoregulation

This project is an exploration of how a single cell living in fresh water is capable of secreting water to maintain the proper balance of water and salts. Protozoa have a contractile vacuole system CVC which presumably does this job.

However, what is not understood is how the water is accumulated within this CVC since all membranes including those surrounding the CVC are permeable to water. One way around the paradox would be for the cell to pump salts into the CVC to maintain a solution within the CVC equal in salt concentration to the cell's cytoplasm.

In this way water would enter the CVC and there would be net backflow of water into the c cytoplasm. Both water and salts would then be secreted from the cell. However, what salts the cell is capable of continually excreting remains unknown. Thus the investigation is undertaken to determine what the contents of the CVC are in the fresh water protozoan Paramecium, thereby determining what the ce ll is excreting through its CVC.

Clues about the types of ion channels and ion pumps driven by the electrical potential across the membrane will be followed-up with experiments using drugs which block specific channels or pumps. The biochemistry of individual ion carriers can be determined using by assaying the electrical properties in an isolated patch of membrane patch clamping.

Now-a-days "Duncan Wigg, EC. Bovee, T L Jahn' in worked on the contractile vacuole of Amoeba and came to the conclusion this contractile vacuole has no contraction capacity. It will rupture only to send out the excess water.

So they called the contractile vacuole as Water pulsating vesicle '. In Paramecium two contractile vacuoles are present. They are surrounded by 6 to 10 radiating canals. Protozoa living in fresh water are subjected to a hypotonic environment.

Water flows across their plasma membrane since their cytosol is always hypertonic to the environment. Many wall-less protozoa have an organelle, the contractile vacuole complex CVC , that collects and expels excess water.

Recent progress shows that most, if not all, CVCs are composed of a two-compartment system encircled by two differentiated membranes.