Amino Acids in the Control of Differentiation of Sporangia in Allomyces macrogynus

Abstract

Of 24 amino acids tested all except glutamic and aspartic acids were able to block completely the transcription of mRNA for zoosporangium production of A. macrogynus within 30 min and for a period of at least 5 h at concentrations which were not excessively toxic. After 5 h terminal resistant sporangia developed with seven of the amino acids and zoosporangia with the others. The uptake, utilization and toxicity of amino acids were explored to explain the differences observed. Conditions for the controlled production of resistant sporangia were optimized for the glucose-leucine combination. Some amino acids were also able to inhibit zoosporangium development after mRNA transcription and before deposition of the septum. In the development of resistant sporangia stable mRNA was involved at least until the wall was acid-resistant. Synthesis of new mRNA was required to convert a developing resistant sporangium to a zoosporangium when the supply of glucose was inadequate.