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The wealth of marine sponges and soft corals in Indonesian waters represents a rich source of natural products. However, anthropogenic pressures potentially decrease diversity in coral reefs. Presented here are trends for tropical sponge and soft coral biodiversity and their bioactivity potential under the influence of increasing anthropogenic pressures. Samples were collected along transects (near, mid, and far) at Karimunjawa and Seribu Islands Marine National Parks and environmental parameters (salinity, pH, dissolved oxygen (DO), phosphate, nitrate, and ammonia), sponge and soft coral biodiversity, and the bioactivity potential of those organisms (50% Growth Inhibition (GI50) of cancer cell lines H460-Lung, MCF7-Breast, and SF268-CNS) are compared. The environmental conditions and biodiversity were found to be significantly different between groups of sampling sites (P

Phytoplankton-bacteria interactions drive the surface ocean sulfur cycle and local climatic processes through the production and exchange of a key compound: dimethylsulfoniopropionate (DMSP). Despite their large-scale implications, these interactions remain unquantified at the cellular-scale. Here we use secondary-ion mass spectrometry to provide the first visualization of DMSP at sub-cellular levels, tracking the fate of a stable sulfur isotope (34S) from its incorporation by microalgae as inorganic sulfate to its biosynthesis and exudation as DMSP, and finally its uptake and degradation by bacteria. Our results identify for the first time the storage locations of DMSP in microalgae, with high enrichments present in vacuoles, cytoplasm and chloroplasts. In addition, we quantify DMSP incorporation at the single-cell level, with DMSP-degrading bacteria containing seven times more 34S than the control strain. This study provides an unprecedented methodology to label, retain, and image small diffusible molecules, which can be transposable to other symbiotic systems. DOI: http://dx.doi.org/10.7554/eLife.23008.001, eLife digest Sulfur is an essential element for many organisms and environmental processes. Every year, organisms including microalgae produce more than one billion tons of a sulfur-containing compound called DMSP. Some of this DMSP is released into seawater, where it acts as a key nutrient for microscopic organisms and as a foraging cue to attract fish. DMSP is also the precursor of a gas that helps to form clouds. Despite DMSP’s potential large-scale effects, it is still not clear what role it plays in the organisms that produce it, or how it is transferred from the microalgae that produce it to the bacteria that use it. It is thought that DMSP could potentially protect the cells from sudden changes in the amount of salt in the seawater (salinity) or from other damage, such as oxidative stress – a build-up of harmful chemicals inside cells. In a controlled setting using artificial seawater, Raina et al. used high-resolution imaging and chemical analysis to track the journey of DMSP from microalgae to recipient bacteria. The results show that similar to land plants, algae store DMSP in the compartments that regulate cell pressure and photosynthesis. The presence of DMSP in these locations also supports its proposed role in protecting cells from changes in salinity or oxidative damage. A future step will be to identify the genes involved in producing DMSP in microalgae. This knowledge could be used to create mutants that are either incapable of producing this molecule or that overproduce it. In combination with the high-resolution imaging techniques described here, this will allow researchers to fully understand the role that DMSP plays in these organisms. DOI: http://dx.doi.org/10.7554/eLife.23008.002

Reef building corals are among the largest producers of dimethylsulfoniopropionate (DMSP), a sulfur molecule synthesized by their endosymbiotic dinoflagellates in the genus Symbiodinium. DMSP is potentially involved in important physiological and ecological processes in corals, but investigating the functional role of this molecule requires rapid and accurate quantification techniques. Here we introduce a simple method enabling direct quantification of DMSP and one of its breakdown products acrylate using quantitative nuclear magnetic resonance (qNMR) spectroscopy. The method was tested on a range of coral genera and presents a number of advantages over currently used quantification techniques, including simultaneous and direct quantification of multiple molecules from the same extract, and rapid processing with high reproducibility enabling analyses of large numbers of samples in short time periods. The method was successfully applied to environmental samples and provides the first baseline information on diel variation of DMSP and acrylate concentrations in the coral Acropora millepora.

Bacterial communities associated with healthy corals produce antimicrobial compounds that inhibit the colonization and growth of invasive microbes and potential pathogens. To date, however, bacteria-derived antimicrobial molecules have not been identified in reef-building corals. Here we report the isolation of an antimicrobial compound produced by Pseudovibrio sp. P12, a common and abundant coral-associated bacterium. This strain was capable of metabolizing dimethylsulfoniopropionate (DMSP), a sulfur molecule produced in high concentrations by reef-building corals and playing a role in structuring their bacterial communities. Bioassay-guided fractionation coupled with nuclear magnetic resonance (NMR) and mass spectrometry (MS), identified the antimicrobial as tropodithietic acid (TDA), a sulfur-containing compound likely derived from DMSP catabolism. TDA was produced in large quantities by Pseudovibrio sp., and prevented the growth of two previously identified coral pathogens, Vibrio coralliilyticus and V. owensii, at very low concentrations (0.5 µg/mL) in agar diffusion assays. Genome sequencing of Pseudovibrio sp. P12 identified gene homologs likely involved in the metabolism of DMSP and production of TDA. These results provide additional evidence for the integral role of DMSP in structuring coral-associated bacterial communities and underline the potential of these DMSP-metabolizing microbes to contribute to coral disease prevention.

The methanol extract of a Sinularia sp., collected from Bowden Reef, Queensland, Australia, yielded ten natural products. These included the new nitrogenous diterpene (4R*,5R*,9S*,10R*,11Z)-4-methoxy-9-((dimethylamino)-methyl)-12,15-epoxy-11(13)-en-decahydronaphthalen-16-ol (1), and the new lobane, (1R*,2R*,4S*,15E)-loba-8,10,13(14),15(16)-tetraen-17,18-diol-17-acetate (2). Also isolated were two known cembranes, sarcophytol-B and (1E,3E,7E)-11,12-epoxycembratrien-15-ol, and six known lobanes, loba-8,10,13(15)-triene-16,17,18-triol, 14,18-epoxyloba-8,10,13(15)-trien-17-ol, lobatrientriol, lobatrienolide, 14,17-epoxyloba-8,10,13(15)-trien-18-ol-18-acetate and (17R)-loba-8,10,13(15)-trien-17,18-diol. Structures of the new compounds were elucidated through interpretation of spectra obtained after extensive NMR and MS investigations and comparison with literature values. The tumour cell growth inhibition potential of 1 and 2 along with loba-8,10,13(15)-triene-16,17,18-triol, 14,17-epoxyloba-8,10,13(15)-trien-18-ol-18-acetate, lobatrienolide, (1E,3E,7E)-11,12-epoxycembratrien-15-ol and sarcophytol-B were assessed against three human tumour cell lines (SF-268, MCF-7 and H460). The lobanes and cembranes tested demonstrated 50% growth inhibition in the range 6.8–18.5 µM, with no selectivity, whilst 1 was less active (GI50 70–175 µM).

Three new merosesquiterpenoids, metachromins U, V, and W (1-3), were isolated from a specimen of the marine sponge Thorecta reticulata collected off Hunter Island, Tasmania, Australia. Structures of the new compounds were elucidated through extensive NMR investigations and comparison with literature values. The cytotoxicities of 1-3 were assessed against a panel of human tumor cell lines (SF-268, H460, MCF-7, and HT-29) and a mammalian cell line (CHO-K1). All compounds were found to have 50% growth inhibition activities in the range 2.1-130 μM, with 2 being the most active (GI50 2.1-10 μM).

A new sesquiterpene benzoxazole, nakijinol B (3), its acetylated derivative, nakijinol B diacetate (6), and two new sesquiterpene quinones, smenospongines B (4) and C (5), were isolated from the methanol extract of the marine sponge Dactylospongia elegans. Also isolated were the known compounds dactyloquinone B and a 1:1 mixture of ilimaquinone and 5-epi-ilimaquinone. Their structures were determined on the basis of spectroscopic analyses and comparison with literature data. The isolated compounds were assessed for their cytotoxicity against a panel of human tumor cell lines (SF-268, H460, MCF-7, and HT-29) and a normal mammalian cell line (CHO-K1). All compounds were found to have activities in the range 1.8-46 μM and lacked selectivity for tumor versus normal cell lines.

Methanol extracts of two specimens of the soft coral Nephthea sp. collected from the Seribu Islands, Indonesia, were active in an anticancer bioassay. One new (1) and four known diterpenes (2–5) based on the cembrane carbon skeleton were isolated from these extracts, as was arachidonic acid (8). The structures of all compounds were elucidated using NMR, including 1,1-ADEQUATE and 1D gradient selective NOESY where applicable to determine the relative stereochemistry. Spectroscopic data, including 1H and 13C NMR, UV, IR and optical rotations are reported when enough material was available and where this has not been done previously. Inhibition assays employing three cancer cell lines, SF-268 (CNS), MCF-7 (breast), and H460 (lung) were used to guide the isolation of all compounds.

From the dichloromethane/methanol extract of the crinoid Colobometra perspinosa, collected south east of Richards Island (Bedara), Family Islands, Central Great Barrier Reef, Australia, 3-(1'-hydroxypropyl)-1,6,8-trihydroxy-9,10-anthraquinone [one of the two stereoisomers of rhodoptilometrin, (1)], 3-propyl-1,6,8-trihydroxy-9,10-anthraquinone (3), 2-[(phenylacetyl)amino]ethanesulfonic acid (4), and 4-hydroxybutanoic acid (5) were isolated. Comparison of (1)H- and (13)C-NMR data for rhodoptilometrin (1) with those reported in the literature showed significant differences for some resonances associated with rings A and C. In an attempt to provide accurately assigned (1)H- and (13)C-NMR data, as well as to confirm the structure of 1, a thorough NMR investigation of this compound was undertaken. Measurements included: concentration dependent (13)C, 1D selective NOE, HSQC, HMBC and 1,1-ADEQUATE. The NMR data for 4 and 5 are reported here for the first time, as is their occurrence from the marine environment. The in vitro anticancer activity of the original extract was found to be associated with 1, 3 and 5.

Eusynstyelamides A-C (1-3) were isolated from the Great Barrier Reef ascidian Eusynstyela latericius, together with the known metabolites homarine and trigonelline. The structures of 1-3, with relative configurations, were elucidated by interpretation of their spectroscopic data (NMR, MS, UV, IR, and CD). The NMR data of 1 were found to be virtually identical to that reported for eusynstyelamide (4), isolated from E. misakiensis, indicating that a revision of the structure of 4 is needed. Eusynstyelamides A-C exhibited inhibitory activity against neuronal nitric oxide synthase (nNOS), with IC(50) values of 41.7, 4.3, and 5.8 microM, respectively, whereas they were found to be nontoxic toward the three human tumor cell lines MCF-7 (breast), SF-268 (CNS), and H-460 (lung). Compounds 1 and 2 displayed mild inhibitory activity toward Staphylococcus aureus (IC(50) 5.6 and 6.5 mM, respectively) and mild inhibitory activity toward the C(4) plant regulatory enzyme pyruvate phosphate dikinase (PPDK) (IC(50) values of 19 and 20 mM, respectively).

Marine bacteria play a central role in the degradation of dimethylsulfoniopropionate (DMSP) to dimethyl sulfide (DMS) and acrylic acid, DMS being critical to cloud formation and thereby cooling effects on the climate. High concentrations of DMSP and DMS have been reported in scleractinian coral tissues although, to date, there have been no investigations into the influence of these organic sulfur compounds on coral-associated bacteria. Two coral species, Montipora aequituberculata and Acropora millepora , were sampled and their bacterial communities were characterized by both culture-dependent and molecular techniques. Four genera, Roseobacter, Spongiobacter, Vibrio , and Alteromonas , which were isolated on media with either DMSP or DMS as the sole carbon source, comprised the majority of clones retrieved from coral mucus and tissue 16S rRNA gene clone libraries. Clones affiliated with Roseobacter sp. constituted 28% of the M. aequituberculata tissue libraries, while 59% of the clones from the A. millepora libraries were affiliated with sequences related to the Spongiobacter genus. Vibrio spp. were commonly isolated from DMS and acrylic acid enrichments and were also present in 16S rRNA gene libraries from coral mucus, suggesting that under “normal” environmental conditions, they are a natural component of coral-associated communities. Genes homologous to dddD , and dddL , previously implicated in DMSP degradation, were also characterized from isolated strains, confirming that bacteria associated with corals have the potential to metabolize this sulfur compound when present in coral tissues. Our results demonstrate that DMSP, DMS, and acrylic acid potentially act as nutrient sources for coral-associated bacteria and that these sulfur compounds are likely to play a role in structuring bacterial communities in corals, with important consequences for the health of both corals and coral reef ecosystems.

Dereplication of a methanolic extract of the marine sponge Ianthella flabelliformis using FTICR-MS accurate mass determination and MS(n) techniques enabled rapid and unambiguous detection of a new compound among a plethora of known compounds. Isolation of this compound and the known 19-deoxy analogue using the hyphenated technique LC-UV/MS-SPE-NMR was undertaken, and the structures were confirmed, from a single chromatographic run, as 19-hydroxyaraplysillin-I N(20)-sulfamate (1) and araplysillin-I N(20)-sulfamate (2).

Eight naturally occurring marine-sponge derived sesquiterpenoid quinones wereevaluated as potential inhibitors of pyruvate phosphate dikinase (PPDK), a C4 plantregulatory enzyme. Of these, the hydroxyquinones ilimaquinone, ethylsmenoquinone andsmenoquinone inhibited PPDK activity with IC50’s (reported with 95% confidenceintervals) of 285.4 (256.4 – 317.7), 316.2 (279.2 – 358.1) and 556.0 (505.9 – 611.0) μM,respectively, as well as being phytotoxic to the C4 plant Digitaria ciliaris. The potentialanti-inflammatory activity of these compounds, using bee venom phospholipase A2(PLA2), was also evaluated. Ethylsmenoquinone, smenospongiarine, smenospongidine andilimaquinone inhibited PLA2 activity (% inhibition of 73.2 + 4.8 at 269 μM, 61.5 + 6.1 at242 μM, 41.0 + 0.6 at 224 μM and 36.4 + 8.2 at 279 μM, respectively). SAR analysesindicate that a hydroxyquinone functionality and a short, hydroxide/alkoxide side-chain atC-20 is preferred for inhibition of PPDK activity, and that a larger amine side-chain at C-20 is tolerated for PLA2 inhibitory activity.

A total of 2,245 extracts, derived from 449 marine fungi cultivated in five types of media, were screened against the C 4 plant enzyme pyruvate phosphate dikinase (PPDK), a potential herbicide target. Extracts from several fungal isolates selectively inhibited PPDK. Bioassay-guided fractionation of one isolate led to the isolation of the known compound unguinol, which inhibited PPDK with a 50% inhibitory concentration of 42.3 ± 0.8 μM. Further kinetic analysis revealed that unguinol was a mixed noncompetitive inhibitor of PPDK with respect to the substrates pyruvate and ATP and an uncompetitive inhibitor of PPDK with respect to phosphate. Unguinol had deleterious effects on a model C 4 plant but no effect on a model C 3 plant. These results indicate that unguinol inhibits PPDK via a novel mechanism of action which also translates to an herbicidal effect on whole plants.

Chemical investigation of the sponge Luffariella variabilis collected from the Palm Island group of the Great Barrier Reef, Australia, yielded three new acetylated compounds, 25-acetoxyluffariellin A (1), 25-acetoxyluffariellin B (2), and 25-acetoxyseco-manoalide (3). The structures of the new compounds were elucidated on the basis of interpretation of their spectroscopic data. The known metabolites manoalide (4), seco-manoalide (5), luffariellin A (8), and manoalide monoacetate (10) were also isolated. The new acetylated compounds (1-3) were labile in the sponge tissue when samples were allowed to thaw prior to extraction, but were stable once isolated. Sponge samples that were completely thawed contained only hydroxylated compounds (alcohols). This finding supported the deduction that the acetylated compounds are being enzymatically transformed and/or degraded.

The majority of marine invertebrates produce dispersive larvae which, in order to complete their life cycles, must attach and metamorphose into benthic forms. This process, collectively referred to as settlement, is often guided by habitat-specific cues. While the sources of such cues are well known, the links between their biological activity, chemical identity, presence and quantification in situ are largely missing. Previous work on coral larval settlement in vitro has shown widespread induction by crustose coralline algae (CCA) and in particular their associated bacteria. However, we found that bacterial biofilms on CCA did not initiate ecologically realistic settlement responses in larvae of 11 hard coral species from Australia, Guam, Singapore and Japan. We instead found that algal chemical cues induce identical behavioral responses of larvae as per live CCA. We identified two classes of CCA cell wall-associated compounds – glycoglycerolipids and polysaccharides – as the main constituents of settlement inducing fractions. These algae-derived fractions induce settlement and metamorphosis at equivalent concentrations as present in CCA, both in small scale laboratory assays and under flow-through conditions, suggesting their ability to act in an ecologically relevant fashion to steer larval settlement of corals. Both compound classes were readily detected in natural samples.

The tetrahydro-β-carboline, callophycin A ( 1 ), was isolated from the methanol extract of the red alga Callophycus oppositifolius collected from Pugh Shoal, north east of Truant Island, Northern Territory, Australia. The structure and relative stereochemistry of 1 was determined through extensive NMR analysis. Callophycin A ( 1 ) was tested against a panel of mammalian cell lines and found to be generally cytotoxic.

The ethanol extract of Pseudoalteromonas strain J010, isolated from the surface of the crustose coralline alga Neogoniolithon fosliei, yielded thirteen natural products. These included a new bromopyrrole, 4′-((3,4,5-tribromo-1H-pyrrol-2-yl) methyl)phenol (1) and five new korormicins G–K (2–6). Also isolated was the known inducer of coral larval metamorphosis, tetrabromopyrrole (TBP), five known korormicins (A–E, previously named 1, 1a–c and 3) and bromoalterochromide A (BAC-A). Structures of the new compounds were elucidated through interpretation of spectra obtained after extensive NMR and MS investigations and comparison with literature values. The antibacterial, antifungal and antiprotozoal potential of 1–6, TBP and BAC-A was assessed. Compounds 1–6 showed antibacterial activity while BAC-A exhibited antiprotozoal properties against Tetrahymena pyriformis. TBP was found to have broad-spectrum activity against all bacteria, the protozoan and the fungus Candida albicans.

This paper provides the first evidence for sperm chemotaxis in the Scleractinia. Montipora digitata Dana, 1845 (Scleractinia: Coelenterata) is a hermaphroditic coral which reproduces bi-annually, releasing egg-sperm bundles during the mass spawning at Magnetic Island (19°10′S; 146°52′E) in late spring-early summer, and autumn each year. The buoyant egg-sperm bundles float to the surface where they break apart, releasing eggs and sperm into the ocean. Fertilisation occurs after ∼30 min. Unfertilized eggs were collected, washed free of sperm, and freeze-dried. The eggs were extracted with dichloromethane, fractionated by chromatography on silica gel, and the fractions assayed for their ability to attract M. digitata sperm. The active fraction was further fractionated by high-performance liquid chromatography, resulting in the isolation of three highly unsaturated fatty alcohols: (1) dodeca-2,4-diynol; (2) tetradec-13-ene-2,4-diynol; (3) (14Z)-heptadeca-14,16-diene-2,4-diynol. Of these three compounds, only Compound 1 attracted sperm of M. digitata. Synthetic Compound 1, produced from simple precursors by known reactions, possessed sperm-attracting activity comparable to the naturally derived attractant. Preliminary experiments suggest that the natural mixture of Compounds 1, 2 and 3 in the ratio 1:4:9 is more effective in attracting sperm from M. digitata than sperm from other Montipora species. Sperm attractants may act to reduce the incidence of hybridisation between different species of Montipora.

Bioassay-guided fractionation of extracts of the brown alga Sporochnus comosus led to the isolation of five new compounds, comosusols A-D (3-6) and comosone A (7). The structures of all isolated compounds were elucidated using standard one- and two-dimensional NMR techniques, as well as comparison with literature values. The cytotoxic activity of all compounds was investigated against a panel of human tumor and mammalian cell lines. These assays found eight of the nine compounds had GI(50) values in the 8-63 μM range.

Two known, but previously uncharacterized, ent-kaurenic acid derivatives, 1 and 2, and four new sesquiterpenes of the eudesmanolide type, 3-6, have been isolated from Wedelia prostata. The structures were eludidated by a range of 1D and 2D high field nmr techniques, and the stereochemistry of the new eudesmanolides was defined from a combination of coupling constant analyses and nuclear Overhauser difference spectra

Maduralide ( 1 ), a novel macrolide possessing a 24-membered ring, was isolated from a marine bacterium grown in liquid culture. The structure of this new metabolite was determined by spectroscopic methods.

The Great Barrier Reef sponge Luffariella variabilis (Poléjaeff 1884) produces a range of potent anti-inflammatory compounds as its major metabolites. These major metabolites-manoalide monoacetate, manoalide, luffariellin A and seco-manoalide-were monitored temporally and spatially to quantify the potential yield from wild harvest or aquaculture. Production of the major metabolites was hardwired at the population level with little variation in space and time over meters to tens of kilometers in the Palm Islands, Queensland, Australia. Manoalide monoacetate (35 to 70 mg g(-1) dry weight of sponge) was consistently the most abundant compound followed by manoalide (15 to 20 mg g(-1) dry weight). Luffariellin A and seco-manoalide were 10 to 70 times less abundant and varied between 0 and 3 mg g(-1) dry weight. On a larger spatial scale, L. variabilis from Davies Reef and Magnetic Island contained the same rank order and yields of compounds as the Palm Islands, indicating a generality of pattern over at least 100 km. The "hardwiring" of metabolite production at the population level by L. variabilis was also reflected in the lack of any inductive effect on metabolite production. In addition, individually monitored sponges produced fixed ratios of the major metabolites over time (years). However, these ratios varied between individuals, with some individuals consistently producing high levels of manoalide and manoalide monoacetate, providing the potential for selection of high-yielding stocks.

Plants using the C(4) photosynthetic pathway are highly represented among the world's worst weeds, with only 4 C(4) species being agriculturally productive (maize, sorghum, millet, and sugar cane). With the C(4) acid cycle operating as a biochemical appendage of C(3) photosynthesis, the additional enzymes involved in C(4) photosynthesis represent an attractive target for the development of weed-specific herbicides. The rate-limiting enzyme of this metabolic pathway is pyruvate orthophosphate dikinase (PPDK). PPDK, coupled with phosphoenolpyruvate carboxylase and nicotinamide adenine dinucleotide-malate dehydrogenase, was used to develop a microplate-based assay to detect inhibitors of enzymes of the C(4) acid cycle. The resulting assay had a Z' factor of 0.61, making it a high-quality assay able to reliably identify active test samples. Organic extracts of 6679 marine macroscopic organisms were tested within the assay, and 343 were identified that inhibited the 3 enzyme-coupled reaction. A high confirmation rate was achieved, with 95% of these hit extracts proving active again upon retesting. Sequential addition of phosphoenolpyruvate and oxaloacetate to the assay facilitated identification of 83 extracts that specifically inhibited PPDK.

The induction of larval attachment and metamorphosis of benthic marine invertebrates is widely considered to rely on habitat specific cues. While microbial biofilms on marine hard substrates have received considerable attention as specific signals for a wide and phylogenetically diverse array of marine invertebrates, the presumed chemical settlement signals produced by the bacteria have to date not been characterized. Here we isolated and fully characterized the first chemical signal from bacteria that induced larval metamorphosis of acroporid coral larvae (Acropora millepora). The metamorphic cue was identified as tetrabromopyrrole (TBP) in four bacterial Pseudoalteromonas strains among a culture library of 225 isolates obtained from the crustose coralline algae Neogoniolithon fosliei and Hydrolithon onkodes. Coral planulae transformed into fully developed polyps within 6 h, but only a small proportion of these polyps attached to the substratum. The biofilm cell density of the four bacterial strains had no influence on the ratio of attached vs. non-attached polyps. Larval bioassays with ethanolic extracts of the bacterial isolates, as well as synthetic TBP resulted in consistent responses of coral planulae to various doses of TBP. The lowest bacterial density of one of the Pseudoalteromonas strains which induced metamorphosis was 7,000 cells mm(-2) in laboratory assays, which is on the order of 0.1-1% of the total numbers of bacteria typically found on such surfaces. These results, in which an actual cue from bacteria has been characterized for the first time, contribute significantly towards understanding the complex process of acroporid coral larval settlement mediated through epibiotic microbial biofilms on crustose coralline algae.

Riset ini bertujuan untuk mengidentifikasi senyawa antibakteri pada Axinella sp . yang diambil dari kepulauan Karimunjawa dengan metode dereplikasi menggunakan LCMS ( Liquid Chromatography Mass Spectrometer ) dan FT-MS ( Fourier Transfer Mass Spectrometer ). Data pola spektra massa dan LC-MS menunjukkan adanya tiga senyawa terbrominasi yang mungkin memiliki bioakfivitas antibakteri. Analisis massa akurat (limit kesalahan di bawah 20 ppm) menggunakan FT-MS menemukan bahwa ketiga senyawa tersebut memliki monosotop negatif (M-H) pada m/z 321,9931 [senyawa (a)]; m/z 383,9089 [senyawa (b)]; dan m/z 385,9249 [senyawa (c)]. Analisis komposisi kimia dari besaran massa tersebut yang menggunakan Elemental Composition Calculator menemukan bahwa komposisi kimia dari ketiga senyawa tersebut adalah C 11 H 10 N 5 O 2 Br (a), C 11 H 9 N 5 Br 2 (b) dan C 11 H 11 Br 2 N 5 O (c). Penelusuran struktur kima yang didasarkan pada komposisi tersebut di database MarinLit 2008 (Database struktur kimia senyawa-senyawa dari biota laut) menemukan bahwa ketiga senyawa tersebut merupakan hymeniadisine (a), 3-bromohymenialdiside (b), dan dibromophakelin (c).

Lophotoxin is a small cyclic diterpene that irreversibly inhibits agonist binding to nicotinic acetylcholine receptors by reacting covalently with Tyr190 in the alpha-subunits of the receptor. Structure/activity and molecular modeling studies were undertaken to investigate the structural and conformational features responsible for this unique biological activity. A total of 18 naturally occurring and 7 chemically modified analogues were evaluated for their ability to inhibit the binding of [125I]-alpha-bungarotoxin to nicotinic acetylcholine receptors on membranes prepared from Torpedo electric organ. When the toxins were incubated with the receptor for short durations they did not slow the initial rate of binding of [125I]-alpha-bungarotoxin, suggesting that they have relatively low reversible affinity. However, their ability to inhibit the equilibrium binding of [125I]-alpha-bungarotoxin increased progressively with longer incubation times, consistent with an irreversible mechanism of action. Comparison of active and inactive analogues allowed identification of a conserved pharmacophore that appeared to be required for irreversible inhibition of the receptor. This pharmacophore contains lactone oxygens and an electron-deficient epoxide that may mimic the acetate oxygens and quaternary ammonium group of acetylcholine, respectively. Computer modeling of the toxins using molecular mechanics and dynamics revealed that the toxins have restricted conformational mobility, thus allowing identification of a minimum-energy conformation. The results allow speculation concerning the site of covalent reaction between Tyr190 and the toxins, the normal function of Tyr190 in binding acetylcholine, and the bound conformation of acetylcholine.

A new linear tetraprenylhydroquinone derivative (3) with an acetic acid unit has been isolated from the marine sponge Ircinia muscarum. The structure of 3 was determined by spectral analysis.

A submersible apparatus has been developed which permits in situ sampling of allelochemical substances released from sessile marine organisms. Concentration of the allomones from sea water is achieved by adsorption on SEP-PAK C-18, reverse-phase cartridges. The procedure is performed under water and causes minimal disturbance to the organism while in its natural habitat. Design and application of this apparatus are detailed. The isolation and identification of toxins released by two species of alcyonarian corals (order Alcyonacea) are described. This represents the first direct in situ isolation of water-borne allelochemicals released from a marine organism.

The faecal pellets from specimens of the prosobranch mollusc Ovula ovum found feeding on the soft coral Sarcophyton sp. at Eclipse Island, Palm Island Group (18°46′S; 146°33′E) in November 1980 were analysed. The only terpene present in the faeces, 7,8-deoxysarcophytoxide, differed from the major constituent of the soft coral, sarcophytoxide, suggesting that the latter had been transformed into the former within the cowrie. This transformation is not trivial, and could not be produced simply by acid catalysis. Subsequent analysis of tissues dissected from different regions of O. ovum indicates that the transformation is probably effected by enzymes in the digestive diverticula stomach region of the prosobranch. The transformed compound is significantly less toxic to the mosquito fish Gambusia affinis Baird and Girard than the ingested compound.

The in vivo incorporation of mevalonolactone specifically into the terpene portion of a sesquiterpene hydroquinone is reported for the soft coral Sinularia capillosa Eudesma -4 , 7(11)- diene -8β- ol ( 20 ) and the corresponding 8-keto derivative ( 21 ) have been isolated from the soft coral Nephthea species for the first time The aeolid nudibranch Phyllodesmium longicirra was collected when feeding on the soft coral Sarcophyton trocheliophorum and the known diterpene trocheliophorol (25) was found to be concentrated in the cerata of the nudibranch. The absolute stereochemistry of trocheliophorol ( 25 ) has been rigorously determined, and shown to be that previously assigned on spectroscopic grounds

5-Nonylpyrrole-2-carbaldehyde has been isolated from a soft coral-sponge association. The structure was determined spectroscopically and confirmed by synthesis.

Two isomeric 7,8-epoxycembra-3,11,15-trien-16,2-olides have been isolated from different species of the soft coral genus Efflatounaria. The structure of each was deduced spectroscopically , and the relative stereochemistry of one was determined by X-ray crystallography. The absolute stereochemistry of each cembranolide was obtained by chemical correlation with known compounds.

5-Nonylpyrrole-2-carbaldehyde has been isolated from a soft coral-sponge association. The structure was determined spectroscopically and confirmed by synthesis.

The isolation of two new cembranoid diterpenes, (14S,1E,3E,7E)-14-acetoxy-11,12-epoxycembra-1,3,7-triene and the corresponding 14-alcohol, is reported from the soft coral Lobophytum sp. A minor component in the extract (3S,4S,1lS,12S,1E,7E)-3,4:11,12-bisepoxycembra-1,7-diene was identified but may be artefactual as it is the sole product of the aerial oxidation of the major metabolite(11S,12S,1 E,3E,7E)-11,12-epoxycembra-1,3,7-triene. Further examples of stereospecific epoxidationsare reported.

Three new diterpenes have been isolated from soft corals of the genus Efflatounaria (Coelenterata, Octocorallia, Alcyonacea, Xeniidae). The structure of the first compound (4) was elucidated on the basis of high-field 1H n.m.r. spectroscopy while that of the second metabolite (5) was determined by single-crystal X-ray analysis. The third diterpene (6) was structurally related to (5), and its structure was confirmed by chemical transformation. All three diterpenes can be derived from xenicin-type precursors, by cleavage and recyclization.

The soft coral Lemnalia cervicornis May 1898 has afforded 13 novel sesquiterpenoid metabolites. The majority were derivatives of calamenen-7-ol and the structures were deduced by 1H and 13C n.m.r . spectroscopy. Absolute stereochemistry of compounds (3)-(13) was determined by chemical correlation with 7-hydroxycalamenen-3-one (3) for which an X-ray structure determination of its 7-p-bromobenzoyl derivative is reported. Two minor metabolites (15) and (16) were not aromatic, but were structurally related to the algal metabolite zonarene (21) for which absolute stereochemistry was available.