Regeneration of test in testate amoebae of the genus Arcella (Tubulinea, Arcellinida).
Although the presence of test is the most fundamental synapomorphy of arcellinid lobose amoebae, the significance of tests in maintenance of the biological functions of these organisms is still largely unclear. This paper demonstrates the effect of the artificial test removal on the behaviour, ultrastructure and reproduction of the testate lobose amoebae belonging to the two species of the genus Arcella. The studied cells can survive after artificial removal of their test, and many specimens are capable of building a test de novo. We investigated this process and found that test-free cells of Arcella in culture remained alive for weeks; they are able to move and feed, but never undergo normal cell division accompanied by mitosis. Test-free cells can restore the test in three different ways: (1) building almost normal test; (2) building a very small single-chambered test; (3) building a test which consisted of several small chambers attached to each other. Although newly constructed tests are abnormal, cells restore shape, size and other characteristic features of the test in the next one or two generations of descendants. The results obtained suggest that the test may be critically important for completing a life cycle of an amoeba.
Department of Invertebrate Zoology, Faculty of Biology and Soil Sciences, St. Petersburg State University, Universitetskaja nab. 7/9, 199034 St. Petersburg, Russia. Electronic address: arcellinidae@gmail.com.
Ekaterina
E
Volkova
Department of Invertebrate Zoology, Faculty of Biology and Soil Sciences, St. Petersburg State University, Universitetskaja nab. 7/9, 199034 St. Petersburg, Russia.
Alexey
A
Smirnov
D008018:Life Cycle Stages; D016840:Lobosea / Q000166:cytology* / Q000502:physiology* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D012038:Regeneration
Amoebozoa; Arcella; Feeding; Regeneration; Testate amoeba