• Natural Product Sciences
• /
• v.9 no.4
• /
• pp.232-234
• /
• 2003

A new glycerol ether has been isolated from a marine sponge Stelletta sp. By bioactivity-guided fractionation. The structure was established on the basis of NMR and MS analyses. The compound was evaluated for cytotoxicity against a small panel of five human tumor cell lines and exhibited significant cytotoxicity.

• Journal of Aquaculture
• /
• v.15 no.3
• /
• pp.139-143
• /
• 2002

Saringosterols have been isolated from the sponge Penares incrustans. The structure of these compounds have been determined by extensive 2-D NMR experiments such as $ ^1 H$ COSY, HMQC, and HMBC and by comparison with published data. Assignment for carbons of saringosterols for the first time has been done.

• Ocean and Polar Research
• /
• v.38 no.4
• /
• pp.287-294
• /
• 2016

Marine sponges have been a remarkably rich source of pharmacologically active and structurally diverse natural products. As a part of our continuing search for novel secondary metabolites of biomedical importance from marine invertebrate, we encountered the sponge Lipastrotethya sp. from Chuuk, Micronesia. The crude organic extract of this animal exhibited considerable cytotoxicity against the K562 cell line. Guided by the $^1H$ NMR analysis, flash chromatography of the crude extract followed by HPLC yielded a new triterpene glycoside, along with ten known saponins of the sarasinoside class. The structure of this new compound was determined by combined spectroscopic methods such as COSY, HSQC and HMBC experiment. Among these metabolites, six compounds exhibited moderate cytotoxicity against ACHN, MDA-MB-231, NCI-H23 and NUGC-3 cell lines.

• Natural Product Sciences
• /
• v.5 no.4
• /
• pp.177-180
• /
• 1999

The ethanolic extracts of two shallow water sponge species collected from the Aegean Sea afforded thirteen terpenoids in total, two of which were determined to be new. The structure elucidation of the terpenoids was carried out by spectroscopic techniques and comparison with related authentic compounds. The terpenoids have also been assayed for antibacterial activity. This is the first report about the metabolites isolated from the marine sponges of the Aegean Sea in Turkey.

• Natural Product Sciences
• /
• v.21 no.4
• /
• pp.237-239
• /
• 2015

Sarcotragin C (1), a new sesterterpene metabolite was isolated from a Sarcotragus sp. sponge collected from Chuja Island, Korea. On the basis of the combined spectroscopic analyses, the structure of this compound was determined to be a linear norsesterterpene containing a leucine-derived ${\gamma}-lactam$ moiety. This compound exhibited moderate cytotoxicity against K562 and A549 cell-lines.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.6
• /
• pp.990-994
• /
• 2007

Bioassay-guided fractionation of the MeOH extract from the sponge Discodermia calyx collected off the coast of Jeju Island, South Korea, led to the isolation of a polyketide, icadamide C (1), along with previously reported theopederin K (3). Structure elucidation was performed by a combination of high resolution mass and 2D-NMR (principally COSY, HMBC, HSQC, and NOESY) spectroscopy. Stereochemistry of compound 1 was determined as 2R*, 3R*, 6R*, 10S*, 11S*, 12R*, 13S*, 15R* and 2'S by NMR data and Marfey analysis. Isolated metabolites displayed potent cytotoxic activity against a small panel of five human solid tumor cell lines with ED50 values of less than 0.1 μg/mL.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.3
• /
• pp.229-237
• /
• 2009

Among 12 marine bacterial strains from the China coast that exhibited interesting bioactivity (positive for both antimicrobial and cytotoxic activities), only four strains, namely, NJ6-3-1, NJ6-3-2, NB-6, and YTHM-17, had a KS domain or A domain when screened for PKS and NRPS genes using a PCR. Interestingly, two of these strains belonging to Pseudoalteromonas and associated with the marine sponge Hymeniacidon perleve were positive for both PKS and NRPS, whereas the other two strains of Pseudoalteromonas did not have a PKS or NRPS gene. A molecular phylogeny analysis and DGGE analysis of the Pseudoalteromonas sp. indicated that they had a specific affinity with the host marine sponge Hymeniacidon perleve. Furthermore, an analysis of a partial sequence of Pseudoalteromonas sp. NJ6-3-2 isolated from the marine sponge Hymeniacidon perleve obtained from genomic walking using a computational approach indicated a relatively complete PKS module including auxiliary domains (DH, KR, and Cy).

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.2 no.1
• /
• pp.21-25
• /
• 2021

We measured the sizes of microstructures and the reflectance of blue feathers in the Common Kingfisher (Alcedo atthis). The colors were mainly produced in the barbs, which were composed of keratin sponge layers with air spaces and melanin rods. The reflectance spectra of back and tail feathers of the Common Kingfisher showed a peak with a broad plateau in the visible wavelength, whereas those of the wing feathers showed peaks in ultraviolet and visible and short-wavelengths. Moreover, the reflectance of back and tail feathers was higher than that of wing feathers. The blue color of the feathers comes from the keratin sponge layer due to coherent scattering. The back and tail feathers are composed of the keratin sponge layer only, and the wing feathers are composed of the keratin sponge layer and the keratin honeycomb structure. Due to the difference in these structures, it supposed that the reflectance is different. Determining why the reflectance spectra of the back and tail feathers were flattened will require further study.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.6
• /
• pp.1775-1781
• /
• 2008

The effects of the type of curing agent on the swelling of the natural rubber(NR) sponge applicable to the self-sealing layer of a helicopter fuel tank were investigated. The curing systems employed were peroxide and mixed ones of sulfur and peroxide. The NR compounds were prepared in a kneader and a roll-mill. The compounds were partially cured in a press at high pressure and subsequently cured fully with expansion in another press at atmospheric pressure. The apparent density of the NR sponge was measured and the cell structure was observed with scanning electron microscopy. The swelling experiments were performed at room temperature using toluene, iso-octane, and an aircraft fuel as a solvent. More rapid volume swelling of the NR sponge cured by peroxide was achieved than cured by sulfur and peroxide with similar amount of curing agent added in rubber compounds. The apparent density and cell structure of the sponge were extremely sensitive to the amount of peroxide, which influences again the swelling behavior of the NR sponge. It is important to control properly two reactions of decomposition of foaming agent and crosslinking of NR in the mold to obtain rapid swelling of the NR sponge on contact of the fuel.

• Journal of the Korean Magnetic Resonance Society
• /
• v.10 no.2
• /
• pp.188-196
• /
• 2006

A known theonellapeptolide Ie, previously reported in other research group, was isolated from the methanolic extract of the Philippine sponge Theonella swinhoei. The planar structure of this compound was determined on the basis of NMR methods including HMBC and selective HMBC experiments. This is fast and efficient for the dereplication of natural products compared with the MS studies of fragments obtained from complete and partial hydrolysis. The sequence of thirteen amino acids including six N-methyl amino acids in the compound was clearly determined from correlations of extensive HMBC experiments.