Artificial tripartite symbiosis involving a green alga (Chlamydomonas), a bacterium (Azotobacter) and a fungus (Alternaria): Morphological and physiological characterization |
| |
Authors: | Z L?rincz é Preininger A Kósa T Pónyi P Nyitrai L Sarkadi G M Kovács B B?ddi and I Gyurján |
| |
Abstract: | A long-living artificial tripartite symbiosis involving a green alga (Chlamydomonas), a bacterium (Azotobacter) and a fungus (Alternaria) was established on carbon- and nitrogen-free medium. The basis of the interdependence is the complementation of photosynthetic
CO2 assimilation and atmospheric nitrogen fixation. Green color of the colonies indicated that the algal cells had enough nitrogen
to synthesize chlorophylls. The chlorophyll content was nearly 40 % of the control cells. The relatively high rate of photosynthetic
oxygen evolution proved that nitrogen was effectively used for building up a well functioning photosynthetic apparatus. This
was supported by the analysis of photosystems and ultrastructural investigations. In comparison with degreened algae cultured
on nitrogen-free medium, the chloroplasts in the symbiont algal cells contained a well-developed, stacked thylakoid membrane
system without extreme starch or lipid accumulation. The occurrence of the fungus in the association greatly increased the
chlorophyll content. Far fewer types of amino acids were excreted by the tripartite cultures than by pure cultures. Cystathionine,
which is a common intermediate in the sulfur-containing amino acid metabolism, was produced in high quantities by the tripartite
symbiosis. This can mostly be attributed to the activity of the fungus. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|