Nitric Oxide and Cnidarian-Dinoflagellate Symbioses: Pieces of a Puzzle

The presence of nitric oxide synthase (NOS) activity is demonstrated in the tropical marine cnidarian Aiptasia pallida and in its symbiotic dinoflagellate algae, Symbiodinium bermudense. Enzyme activity was assayed by measuring the conversion of arginine to citrulline. Biochemical characterization of NOS from Aiptasia was characterized with respect to cellular localization, substrate and cofactor requirements, inhibitors, and kinetics. In response to acute temperature shock, anemones retracted their tentacles. Animals subjected to such stress had lower NOS activities than did controls. Treatment with NOS inhibitors caused tentacular retraction, while treatment with the NOS substrate L-arginine inhibited this response to stress, as did treatment with NO donors. These results provide a preliminary biochemical characterization of, and suggest a functional significance for, NOS activity in anthozoan-algal symbiotic assemblages

Prominent Human Health Impacts from Several Marine Microbes: History, Ecology, and Public Health Implications

This paper overviews several examples of important public health impacts by marine microbes and directs readers to the extensive literature germane to these maladies. These examples include three types of dinoflagellates (Gambierdiscus spp., Karenia brevis, and Alexandrium fundyense), BMAA-producing cyanobacteria, and infectious microbes. The dinoflagellates are responsible for ciguatera fish poisoning, neurotoxic shellfish poisoning, and paralytic shellfish poisoning, respectively, that have plagued coastal populations over time. Research interest on the potential for marine cyanobacteria to contribute BMAA into human food supplies has been derived by BMAA's discovery in cycad seeds and subsequent implication as the putative cause of amyotrophic lateral sclerosis/parkinsonism dementia complex among the Chamorro people of Guam. Recent UPLC/MS analyses indicate that recent reports that BMAA is prolifically distributed among marine cyanobacteria at high concentrations may be due to analyte misidentification in the analytical protocols being applied for BMAA. Common infectious microbes (including enterovirus, norovirus, Salmonella, Campylobacter, Shigella, Staphylococcus aureus, Cryptosporidium, and Giardia) cause gastrointestinal and skin-related illness. These microbes can be introduced from external human and animal sources, or they can be indigenous to the marine environment

The Efflux of Amino Acids from the Olfactory Organ of the Spiny Lobster: Biochemical Measurements and Physiological Effects

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Molecular diversity of symbiotic algae at the latitudinal margins of their distribution: dinoflagellates of the genus Symbiodinium in corals and sea anemones

To investigate the molecular diversity of symbiotic algae at the latitudinal limits of their distribution, the ribosomal RNA gene sequences (rDNA) of the dinoflagellate Symbiodinium in benthic Cnidaria (corals, sea anemones etc.) on Bermuda (32°N) and in the Mediterranean and NE Atlantic (35 to 53°N) were analysed. The algae in Bermudian Cnidaria were identified as Symbiodinium of Phylotypes A, B and C, as previously described for benthic Cnidaria in the Caribbean (12 to 27°N). The algae in every sample of sea anemones (Anemonia spp. and Cereus pedunculatus) in the NE Atlantic and Mediterranean were a previously undescribed group within Phylotype A, possibly endemic to this high latitude region

Increased zooxanthellae nitric oxide synthase activity is associated with coral bleaching

Coral bleaching, the breakdown of the symbiotic relationship between host corals and their photosynthetic dinoflagellate endosymbionts, is a phenomenon of major ecological significance. The cellular and molecular mechanisms underlying bleaching are poor