Dendronephthya Sp Research Articles

On some commensal anomuran and brachyuran crabs (Crustacea: Decapoda) off Visakhapatnam, Northwestern Bay of Bengal.

Commensal anomuran and brachyuran crabs were collected from extensive exploratory surveys on rocky areas where soft corals, sea anemones and sponges are found off the Visakhapatnam coast. The present study includes nine species of commensal decapod crustaceans, comprising four porcellanid crabs (Petrolisthes lamarckii (Leach, 1820), Porcellanella triloba White, 1852, Polyonyx hendersoni Southwell, 1909 and Pisidia gordoni (Johnson, 1970)), one squat lobster (Allogalathea elegans (Adams, 1847) and four brachyuran crabs (Dorippoides facchino (Herbst, 1785), Quadrella coronata Dana, 1852, Quadrella maculosa Alcock, 1898 and Sphenomerides trapezioides (Wood-Mason & Alcock, 1891). Allogalathea elegans, Polyonyx hendersoni, Pisidia gordoni, Quadrella coronata and Quadrella maculosa are new records from off Visakhapatnam. The porcellanid crabs are associated with the sea pen Pteroeides esperi, desmosponges and black soft corals Antipathes sp. whereas the squat lobster was associated with the soft coral Dendronephthya sp. The brachyuran crabs were observed in association with Antipathes sp. Here, we provide details on the morphology, distribution, habitat and commensalism of decapod crustaceans studied.

New 1,4-Dienonesteroids from the Octocoral Dendronephthya sp.

Two new steroids, dendronesterones D (1) and E (2), featuring with 1,4-dienone moiety, along with three known steroids, methyl 3-oxochola-4,22-diene-24-oate (3), 5α,8α-epidioxy-24(S)- methylcholesta-6,22-dien-3β-ol (4), and 5α,8α-epidioxy-24(S)-methylcholesta-6,9(11),22-trien-3β-ol (5), were isolated from an octocoral Dendronephthya sp. The structures of steroids 1 and 2 were elucidated by using spectroscopic methods and steroid 1 was found to exhibit significant in vitro anti-inflammatory activity in lipopolysaccharides (LPS)-induced RAW264.7 macrophage cells by inhibiting the expression of the iNOS protein.

Ph-Sensor Properties of a Fluorescent Protein from Dendronephthya sp

Genetically encoded biosensors based on fluorescent proteins are now widely applicable for monitoring pH changes in live cells. Here, we have shown that a fluorescent protein from Dendronephthya sp. (DendFP) exhibits a pronounced pH-sensitivity. Unlike most of known genetically encoded pH-sensors, fluorescence of the protein is not quenched upon medium acidification, but is shifting from the red to green spectral range. Therefore, quantitative measurements of intracellular pH are feasible by ratiometric comparison of emission intensities in the red and green spectral ranges, which makes DendFP advantageous compared with other genetically encoded pH-sensors.

Isolation, Identification and Growth Optimization of Microalgae Derived from Soft Coral Dendronephthya sp.

Despite its beauty in shape and color, soft coral Dendronephthya sp. is less interesting commercially as an ornamental coral commodity due to its low chances of survival in artificial habitats. Unlike other corals, this species is azooxhantellae, and thus, it depends on external feeding. The aim of this research is to isolate, identify, and cultivate the microalgae derived from Dendronephthya sp. The microalgae was isolated from digestive tract, followed by genomic DNA isolation and Polymerase Chain Reaction. The algae cultivation was conducted using the nitrogen sources as proven treatment. Five species of microalgae (Amphora sp., Navicula salinicola, Meyerella planktonica, Nannochloris sp., and Nitzschia inconspicua) were successfully isolated. The highest biomass of Amphora sp. was obtained when ammonium was added as nitrogen source. Meanwhile, the highest biomass of N. inconspicua was obtained through the addition of nitrate. Finally, the highest biomass of N. salinicola was acquired when a combination of ammonium and nitrate was used.

Population Dynamic of Dendronephthya sp.-Associated Bacteria in Natural and Artificial Habitats

Dendronephthya sp. is a soft coral that has huge distribution starting from Indopacific, Tonga, Solomon Islands to Great Barrier Reef in Australia. However, this soft corals survive only in short period after cultivation in artificial habitat (aquarium). Recent study showed that the soft coral Dendronephtya sp. has an association or symbiotic relationship with several bacteria, commonly known as coral associated bacteria (CAB). In this study, we compared the population dynamic of Dendronephthya sp.-associated bacteria in natural and artificial habitat, resulting different bacterial community profiles using terminal restriction fragment length polymorphism (T-RFLP) analysis of bacterial community DNA. There were 15 main classes of bacterial population identified along with uncultured microorganism, uncultured organism, uncultured bacteria and unidentified organism. Members of Actinobacteria, Arthrobacteria, Chlorobia, Caldilineae, Δ-proteobacteria and Proteobacteria were predicted to give contributions in the survival ability of both Dendronephthya sp. The cultivation of soft corals after 2 weeks in artificial habitat increases bacterial population similarity on 2 different samples by 10%. Bacterial population similarity in artificial habitat would increase along with the longer cultivation time of soft corals.

Janthinolide A and B, Two New 2,5‐Piperazinedione Derivatives from the Endophytic Penicillium janthinellum Isolated from the Soft Coral Dendronephthya sp.

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Steroids from the soft coral Dendronephthya sp.

Fifteen steroids were isolated from the soft coral Dendronephthya sp., of which five are determined as new compounds, namely (22 E)-3- O- β-formylcholest-5,22-diene ( 1), (22 E)-3- O- β-formyl-24-methyl-cholest-5,22-diene ( 2), 2-ethoxycarbonyl-2- β-hydroxy-A-nor-cholest-5-ene-4-one ( 3), (22 E)-2-ethoxycarbonyl-2- β-hydroxy-A-nor-cholest-5,22-diene-4-one ( 4), and (22 E)-2-ethoxycarbonyl-2- β-hydroxy-24-mthyl-A-nor-cholest-5,22-diene-4- one ( 5). 1 and 2 belonged to 3- O-formylated cholesterol analogues, and 3 to 5 are unique ring A-contracted steroids. Their structures were elucidated by extensive 2D NMR in association with IR, MS analysis.

Photoconversion of the chromophore of a fluorescent protein from Dendronephthya sp.

A green fluorescent protein from the coral Dendronephthya sp. (Dend FP) is characterized by an irreversible light-dependent conversion to a red-emitting form. The molecular basis of this phenomenon was studied in the present work. Upon UV-irradiation at 366 nm, the absorption maximum of the protein shifted from 494 nm (the green form) to 557 nm (the red form). Concurrently, in the fluorescence spectra the emission maximum shifted from 508 to 575 nm. The green form of native Dend FP was shown to be a dimer, and the oligomerization state of the protein did not change during its conversion to the red form. By contrast, UV-irradiation caused significant intramolecular changes. Unlike the green form, which migrates in SDS-polyacrylamide gels as a single band corresponding to a full-length 28-kD protein, the red form of Dend FP migrated as two fragments of 18- and 10-kD. To determine the chemical basis of these events, the denatured red form of Dend FP was subjected to proteolysis with trypsin. From the resulting hydrolyzate, a chromophore-containing peptide was isolated by HPLC. The structure of the chromophore from the Dend FP red form was established by methods of ESI, tandem mass spectrometry (ESI/MS/MS), and NMR-spectroscopy. The findings suggest that the light-dependent conversion of Dend FP is caused by generation of an additional double bond in the side chain of His65 and a resulting extension of the conjugated system of the green form chromophore. Thus, classified by the chromophore structure, Dend FP should be referred to the Kaede subfamily of GFP-like proteins.

Some toxicological characteristics of three venomous soft corals from the Red Sea

Three common Red Sea soft corals (Cnidaria: Anthozoa), Nephthea sp, Dendronephthya sp and Heteroxenia fuscescens sting humans. Nematocyst venoms of each animal are lethal to mice and hemolytic to human erythrocytes. However, these hemolysins are partially inhibited by known anti-hemolytic agents. Venoms and their gel chromatography-separated fractions have different dermonecrosis and vasopermeability potency in mouse skin. The venom of Heteroxenia fuscescens (Hf) was more lethal (LD 50: 0.7 mg/kg), with one prominent 97-kDa protein fraction (LD 50: 0.55 mg/kg). Hf venom was more hemolytic, more dermonecrotic, and had more vasopermeable factors than that of the two other species. SDS polyacrylamide gel electrophoresis of soft coral whole venoms and fractions showed different protein molecular masses ranging from 200 to less than 6 kDa. High IgG titers were assayed from venom-sensitized mice blood sera. Enzyme-linked immunosorbent assays (ELISA) marked significant immunological cross-reaction between the studied soft coral venoms and their bioactive fractions.

Phytoplankton: a significant trophic source for soft corals?

Histological autoradiographs and biochemical analyses show that 14C-labelled microalgae (diatoms, chlorophytes and dinoflagellates) are used by the soft coral Dendronephthya sp. Digestion of the algae took place at the point of exit of the pharynx into the coelenteron. Ingestion and assimilation of the labelled algae depended on incubation time, cell density, and to a lesser extent on species-specificity. 14C incorporation into polysaccharides, proteins, lipids and compounds of low molecular weight was analysed. The 14C-labelling patterns of the four classes of substances varied depending on incubation time and cell density. 14C incorporation was highest into lipids and proteins. Dissolved labelled algal metabolites, released during incubation into the medium, contributed between 4% and 25% to the total 14C activity incorporated. The incorporated microalgae contributed a maximum of 26% (average of the four species studied) to the daily organic carbon demand, as calculated from assimilation rates at natural eucaryotic phytoplankton densities and a 1 h incubation period. The calculated contribution to the daily organic carbon demand decreased after prolonged incubation periods to about 5% after 3 h and to 1–3% after 9 h. Thus the main energetic demand of Dendronephthya sp. has to be complemented by other components of the seston.

Four new steroids from two octocorals

In search of analogues of isogosterones A-D (1-4), a group of antifouling 13,17-seco-steroids found in octocorals of the order Alcyonacea, we have isolated four new steroids possessing aromatic, enone, or dienone A-rings from two octocorals, Alcyonium gracillimum and Dendronephthya sp. These compounds, 3-methoxy-19-norpregna-1,3, 5(10),20-tetraene (5), 3-(4-O-acetyl-6-deoxy-beta-galactopyranosyloxy)-19-norpregna-1,3, 5(10),20-tetraene (6), 22,23-dihydroxycholesta-1,24-dien-3-one (7), and methyl 3-oxochola-4,22-dien-24-oate (8), showed no antifouling activity against barnacle (Balanus amphitrite) larvae, but lethality to barnacle larvae at a concentration of 100 &mgr;g/mL (LD(100)).

Isogosterones A−D, Antifouling 13,17-Secosteroids from an Octocoral Dendronephthya sp.

Four antifouling secosteroids named isogosterones A−D (1−4) have been isolated from a Japanese octocoral Dendronephthya sp. Their structures were elucidated on the basis of spectroscopic data as 12α-acetoxy-13,17-seco-cholesta-1,4-dien-3-ones possessing a hemiacetal or acetal functionality. Isogosterones inhibited larval settlement of the barnacle Balanus amphitrite with an EC50 value of 2.2 μg/mL.

Chemical studies on antifouling substances in marine invertebrates. Part 1. Antifouling Substances against the Mussel in an Octocoral Dendronephthya sp.

In a study of antifouling substances against the blue mussel Mytilus edulis L., 11 out of 23 acetone extracts of marine invertebrates collected in the Ogasawara Islands showed antifouling activities. One of active species, an octocoral Dendronephthya sp., gave sterols and a fatty acid mixture mainly composing of C16, and C18 acids as active constituents. A comparison of the antifouling activities of various fatty acids suggested that unsaturated fatty acids were thought to be responsible for the activity.Since fatty acids were commonly detected in other active extracts, they might play an important role in antifouling activities in marine invertebrates.