Protistology 3 (1) 9–14 (2003) Effects of nitrogen-containing compounds on the change in chemotaxis mode during gametogenesis
of Chlamydomonas reinhardtii
Elena V. Ermilova, Zhanna M. Zalutskaya, Tatyana V. Lapina and Maksim M. Nikitin
Laboratory of Microbiology, Biological Research Institute of St. Petersburg State University, St. Petersburg,
Russia
Summary
Chemotactic behavior of Chlamydomonas reinhardtii is changed during gametogenesis.
Vegetative cells exhibit chemotaxis to ammonium ion. In the light, nitrogen deprivation
induces the differentiation of vegetative cells into gametes that are not attracted to
ammonium ion. Some L-amino acids affected the conversion of vegetative cells into
chemotactically inactive cells. This strong effect of L-amino acids was due to their
assimilation product, ammonium ion. Other utilizable sources of organic nitrogen,
such as urea and adenine, were also able to block the loss of chemotaxis to ammonium.
Intracellular ammonium ion generated by assimilation of organic nitrogen sources,
e.g. amino acids, urea and purines, is supposed to repress the change in chemotaxis
mode during gametogenesis of C. reinhardtii.
Key words: Chlamydomonas reinhardtii, chemotaxis, gametogenesis, nitrogen control
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