Ejection of algae in the green hydra symbiosis

✍ Scribed by McAuley, P. J.

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 786 KB
• Volume: 217
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402170104

✦ Synopsis

Abstract

Green hydra appears to regulate strictly the symbiotic algae within its digestive cells. Numbers of algae in the Frome and Jubilee strains were not affected by either sulphate enrichment of the medium or starvation, although numbers of algae fell when photosynthesis was inhibited by darkness and /or DCMU, due to cessation of algal growth. Treatment with glycerol or the antibiotic trimethoprim caused ejection of algae; trimethoprim, but not glycerol, also inhibited algal growth. Glycerol and trimethoprim caused an increase in numbers of algae at the apical ends of digestive cells, and appearance of cohesive algal pellets in treated hydras' coelenterons and in the culture dish; in control hydra and those treated with darkness or DCMU, fewer algae were at the apexes of digestive cells, and no algal pellets were produced. It was concluded that ejection of algae is not the normal regulatory mechanism in the green hydra symbiosis, although the fact that certain treatments may cause algal ejection should be taken into account when algal proliferation is measured in green hydra.