Regulation of Green Fluorescent Proteins by Sea Anemones (Anthopleura spp.) in Response to Light.

Green fluorescent proteins (GFPs) are a family of proteins with a disjunct systematic distribution; their biological functions remain speculative for the most part. Here, we report studies of three closely related species of green sea anemones (Anthopleura) that express GFPs throughout their ectoderm. Individuals of these species maintain facultative symbiosis with zooxanthellae in their endoderm and inhabit the rocky intertidal or shallow subtidal.

Field biology of placozoans (Trichoplax): distribution, diversity, biotic interactions.

The goal of this review is to highlight what little is known, and point to the bulk of what is yet to be learned, about the natural history of placozoans in the field-in order to stimulate a broader search for placozoans and a fuller exploration of their distribution, diversity, and all other aspects of their enigmatic lives. The documented geographic distribution of placozoans lies mostly in the nearshore, warm, marine waters of the tropics and subtropics. Although placozoans have long been viewed as benthic organisms, they can be more readily collected from the water column, well above the sea bottom.

MODIFICATION OF SEA ANEMONE BEHAVIOR BY SYMBIOTIC ZOOXANTHELLAE: EXPANSION AND CONTRACTION.

The pattern of expansion and contraction by the sea anemone Anthopleura elegantissima differs in individuals with or without endosymbiotic zooxanthellae. Anemones without zooxanthellae, found in dark habitats, do not regularly expand or contract under changes in light. Anemones with zooxanthellae expand in moderate light and contract in intense light or in darkness, with striking uniformity.

MODIFICATION OF SEA ANEMONE BEHAVIOR BY SYMBIOTIC ZOOXANTHELLAE: PHOTOTAXIS.

The sea anemone Anthopleura elegantissima, with and without endosymbiotic zooxanthellae, was tested for evidence of phototactic behavior. Anemones with zooxanthellae always displayed phototaxis, either positive or negative depending on the experimental light intensity and the light intensity of the habitat from which the animals were taken. Anemones without zooxanthellae-even those that had previously harbored zooxanthellae and that were genetically identical clone-mates of phototactic individuals-never displayed phototaxis, appearing completely indifferent to light and shade.