Transformations of arsenic in the marine environment

It is ten years since arsenobetaine was first isolated from the western rock lobster Palinurus cygnus. Subsequently this naturally-occurring arsenical has been found in many species of marine animals contributing to the human diet. The identification of arsenic-containing ribofuranosides in algae and the production of dimethylarsinoylethanol from their anaerobic decomposition has allowed speculation on arsenic metabolism in marine organisms and has suggested a possible route to arsenobetaine from oceanic arsenate.     

Dimethyloxarsylethanol from anaerobic decomposition of brown kelp (Ecklonia radiata): A likely precursor of arsenobetaine in marine fauna

Summary The novel arsenic compound, dimethyloxarsylethanol, has been isolated from anaerobically incubatedEcklonia radiata. It is proposed that this compound has a key position in the biosynthesis of arsenobetaine.C, H microanalyses were performed by the Australian Microanalytical Service.     

A novel antagonist of serotonergic receptors,hymenidin, isolated from the Okinawan marine spongeHymeniacidon sp.

Summary A novel bromine-containing pyrrole compound, hymenidin, has been isolated from the Okinawan marine spongeHymeniacidon sp. as a potent antagonist of serotonergic receptors and its structure elucidated using spectral data.     

Bromosphaerodiol,a minor bromo compound from the red algaSphaerococcus coronopifolius

Summary A minor bromoditerpene, bromosphaerodiol, has been isolated from the chloroform extract of the red marine algaSphaerococcus coronopifolius and its structure has been established by chemical and spectroscopic methods.This investigation was supported by Consiglio Nazionale delle Ricerche, Roma.     

Purealidin A,a new cytotoxic bromotyrosine-derived alkaloid from the Okinawan marine spongePsammaplysilla purea

Summary A new bromotyrosine-derived alkaloid with antileukemic activity, purealidin A (5), has been isolated from the Okinawan marine spongePsammaplysilla purea and its chemical structure elucidated on the basis of the spectroscopic data.     

A potent actomyosin ATPase activator from the Okinawan marine spongeAgelas cf.nemoechinata

Summary A bromine-containing alkaloid, oxysceptrin, has been isolated as a potent actomyosin ATPase activator from the Okinawan marine spongeAgelas cf.nemoechinata, and the structure elucidated to be1 on the basis of the 2D NMR spectral data.Acknowledgments. We thank Mr Z. Nagahama for his help in sponge collecting and Ms M. Takamatsu for her technical assistance.     

Natural selection for resistance to mercury pollution

Summary The survival under conditions of mercury pollution of two natural populations of the marine gastropodCerithium rupestre, derived from mercury-polluted and mercury-free sites, was tested in the laboratory. The results indicate a significantly higher survival rate for animals derived from the mercury-polluted site, in each of six repetitive experiments. We conclude that mercury resistance in marine organisms is reinforced in mercury polluted sites, presumably by natural selection for increased resistance. The evolution of metal tolerance in marine organisms may be as fast as that of metal tolerance in plants and the evolution of industrial melanisms in moths.     

Plakorin,a potent Ca2+-ATPase activator from the Okinawan marine spongePlakortis sp.

Summary A new cyclic peroxide, plakorin, which is a potent sarcoplasmic reticulum (SR) Ca^a+-ATPase activator has been isolated from the Okinawan marine spongePlakortis sp., its structure was elucidated on the basis of spectral data.Acknowledgments. We thank Ms M. Hamashima and Ms A. Muroyama for their technical assistance.     

Inhibitory effect of halocyamine,an antimicrobial substance from ascidian hemocytes,on the growth of fish viruses and marine bacteria

Summary Halocyamine A, an antimicrobial substance isolated from hemocytes of the solitary ascidianHalocynthia roretzi, inhibited in vitro the growth of fish RNA viruses (infectious hematopoietic necrosis virus and infectious pancreatic necrosis virus). Pretreatment of RNA virus with halocyamine A reduced the infectivity of the virus toward host cells. The growth of marine bacteria,Achromobacter aquamarinus andPseudomonas perfectomarinus, was also inhibited by halocyamine A but that ofAlteromonas putrefaciens andVibrio anguillarum was not. These results suggest that halocyamine may have a role in the defense mechanisms ofH. roretzi against marine viruses and bacteria.     

Possible origin of zeaxanthin in the marine sponge,Reniera japonica

As part of a study to clarify the origins of biologically active substances in marine sponges, the carotenoids produced by two species of marine bacteria,Flexibacter sp. strain number DK30213 and DK30223, associated with the marine sponge,Reniera japonica, were investigated. Both bacteria were found to produce zeaxanthin [(3R, 3R)-dihydroxy-,-carotene] which is widely distributed in marine organisms. This carotenoid was also detected in the host sponge, suggesting the transport of zeaxanthin from the microorganisms to the host. As zeaxanthin plays the role of a quencher and scavenger for active species of oxygen, it is presumed that the sponge accumulates the bacterial product as a defense substance against the active oxygen species produced under irradiation by strong sunlight. It is thought that the bacteria are symbionts of the host sponge and act by obtaining the solid substrate and medium needed for settlement and growth from the host, and by producing and transmitting the biologically active substance to the host. Zeaxanthin-producing bacteria are also considered to have potential for practical uses by the aquacultural, pharmaceutical and food industries.     

Lipopurealins,novel bromotyrosine derivatives with long chain acyl groups,from the marine spongePsammaplysilla purea

Summary Lipopurealin-A,-B and-C have been isolated from the Okinawan marine spongePsammaplysilla purea. They are inhibitors of Na, K-ATPase, and the structures have been elucidated on the basis of spectral data. They are bromotyrosine derived structures with saturated long chain acyl parts.Physiologically active marine natural products from Porifera X. Preceding paper: Nakamura, H., Wu, H., Kobayashi, J., Nakamura, Y., Ohizumi, Y., and Hirata, Y., Tetrahedron Lett.26 (1985) 4517.     

Extraordinary levels of cadmium and zinc in a marine sponge,Tedania charcoti Topsent: inorganic chemical defense agents

The Antarctic marine spongeTedania charcoti has been shown to contain extraordinarily high natural concentrations of cadmium and zinc, which have in turn been correlated to the ability of the crude ethanol extract to modulate protein phosphorylation in chicken forebrain and to inhibit the growth of several test bacteria.     

Hymenin,a novel α-adrenoceptor blocking agent from the Okinawan marine spongeHymeniacidon sp.

Summary A novel bromine-containing alkaloid, hymenin, has been isolated from the Okinawan marine spongeHymeniacidon sp. as a potent -adrenoceptor blocking agent and its structure determined to be1 on the basis of the spectral data.     

Inhibitory effect of bacterial ubiquinones on the settling of barnacle,Balanus amphitrite

In an attempt to clarify the influence of marine bacteria on the settling of fouling invertebrate larvae, we screened for inhibitors, produced by marine bacteria, of settling by cyprids of the barnacle,Balamus amphitrite. We found that the culture broth ofAlteromonas sp. strain number KK10304, which was associated with the marine sponge,Halichondria okadai, effectively inhibited settling of the cyprids. Bioassay-guided isolation indicated ubiquinone-8 (1) as an effective inhibitor of cyprid settling. As ubiquinones are widely distributed in bacteria, several related compounds were also tested.     

Diasteroisomeric ichthyotoxic acylglycerols from the dorsum of two geographically distinct populations ofArchidoris nudibranchs

Two marine opisthobranchs,Archidoris tuberculata from Asturias (N. Spain) andArchidoris carvi from Patagonia (S. Argentina), contain in their dorsum diasteroisomeric ichthyotoxic acylglycerols esterified in position 1-sn by antipodal diterpenoid acids.     

13C NMR-study of osmoregulatory metabolites in the marine molluscTapes watlingi

Summary Examination of homogenates of tissue from the marine bivalve molluscTapes watlingi by natural-abundance¹³C NMR indicates that taurine, betaine, and some free amino acids play a significant role in osmoregulation.Acknowledgments. We thank Dr L.J. Borowitzka and D.D. Jamieson of this Institute for helpful discussions, and the RRIMP marine biology staff for assistance in collecting the animals.Queen Elizabeth II Fellow in Marine Science, 1976–1978. Please address correspondence to this author.     

In situ accumulation of marine algal exudate by a polychaete worm (Schizobranchia insignis)

Summary For the first time, heterotrophic accumulation of dissolved carbon by a soft-bodied marine invertebrate under in situ conditions has been demonstrated. The polychaete wormSchizobranchia insignis Bush concentrated¹⁴C-labelled dissolved carbon (DC) exudated by the large brown alga,Macrocystis integrifolia Bory, 14 times over the killed controls. Our evidence suggests that algal exudate may be a significant nutritional supplement to some invertebrates cohabitating withM. integrifolia.This study was supported by Operating Grant No. A6966 to PVF from the National Research Council of Canada.We are grateful to MrG. F. Cota, Dalhousie University, Halifax, for his contributions to the field experiments.     

Scalarolbutenolide,a new sesterterpenoid from the marine spongeSpongia nitens

Summary A new sesterterpenoid, scalarolbutenolide (5), has been isolated from the marine spongeSpongia nitens; its structure, including the absolute stereochemistry, has been established by chemical and spectroscopic studies.This work is a part of the Progetto Finalizzato per l'Oceanografia e i Fondi Marini, C.N.R., Roma.We are indebted to A. Crispino, C. Di Pinto, G. Scognamiglio and R. Turco for their technical assistance.     

Cyanobacterial symbiont biosynthesis of chlorinated metabolites fromDysidea herbacea (Porifera)

The tropical marine spongeDysidea herbacea contains large numbers of a symbiotic filamentous cyanobacterium identified on the basis of a detailed ultrastructural study asOscillatoria spongeliae. We report the flow-cytometric separation of the symbiont from the sponge cells, and demonstrate by chemical analyses that a unique group of polychlorinated compounds isolated from the whole sponge tissue is limited to the cyanobacterial filaments, whereas the accompanying sesquiterpenoids are found only in the sponge cells. This is the first demonstration that secondary metabolites ascribed to a sponge are localized in prokaryotic symbiont cells.     

Measuring toxicity in marine environments: critical appraisal of three commonly used methods

Toxicity quantification is important in environmental monitoring, in the field of natural products, and in chemical ecology. The sensitivity and precision of three commonly used methods detecting toxicity in marine environments were compared, using the toxic marine spongeCrambe crambe as a test organism. The paper disk diffusion method (run with marine bacteria) showed the least sensitivity and did not permit toxicity levels to be quantified. The sea urchin and the MICROTOX® tests showed greater sensitivity, and the latter had the higher precision. The relative performance of these methods is discussed. It is concluded that the MICROTOX® bioassay displays the best characteristics for toxicity quantification.