structures and antimicrobial activities of pyridoacridine alkaloids isolated from different chromotypes of the ascidian cystodytes dellechiajei.three new pentacyclic alkaloids were isolated from different chromotypes of the western mediterranean ascidian cystodytes dellechiajei. the purple color morph collected in catalonia contained the known compounds kuanoniamine d (1), shermilamine b (2), n-deacetylkuanoniamine d (3), and styelsamine c (4) and a new alkaloid named n-deacetylshermilamine b (5). the green color morph collected in the balearic islands contained the known compounds 11-hydroxyascididemin (6) and 8,9-dihydro-11-hydroxyasc ...201020491501
ammonia-oxidizing crenarchaeota and nitrification inside the tissue of a colonial ascidian.marine crenarchaeota represent an abundant component of the oceanic microbiota that play an important role in the global nitrogen cycle. here we report the association of the colonial ascidian cystodytes dellechiajei with putative ammonia-oxidizing crenarchaeota that could actively be involved in nitrification inside the animal tissue. as shown by 16s rrna gene analysis, the ascidian-associated crenarchaeota were phylogenetically related to nitrosopumilus maritimus, the first marine archaeon iso ...200818793310
cytotoxicity of the ascidian cystodytes dellechiajei against tumor cells and study of the involvement of associated microbiota in the production of cytotoxic compounds.many cytotoxic compounds of therapeutic interest have been isolated from marine invertebrates, and some of them have been reported to be of microbial origin. pyridoacridine alkaloids are the main compounds extracted from the ascidian cystodytes dellechiajei. here we describe the in vitro antiproliferative activity against different tumor cell lines of the ascidian extracts and provide some insights on the role of the microbial community associated with the tunicate in the production of these com ...200718463720
microbial community associated with the colonial ascidian cystodytes dellechiajei.the ascidian cystodytes dellechiajei (della valle, 1877) (phylum chordata, class ascidiacea, family polycitoridae) is a colonial tunicate that inhabits benthic rock environments in the atlantic, pacific and indian oceans, as well as the mediterranean sea. its life cycle has two phases, the adult sessile colony and the free-living larva. both adult zooids and larvae are surrounded by a protective tunic that contains several eukaryotic cell lines, is composed mainly of acidic mucopolysacharides as ...200717222150
inhibition of topoisomerase ii by the marine alkaloid ascididemin and induction of apoptosis in leukemia cells.ascididemin (asc) is a pentacyclic dna-intercalating agent isolated from the mediterranean ascidian cystodytes dellechiajei. this marine alkaloid exhibits marked cytotoxic activities against a range of tumor cells, but its mechanism of action remains poorly understood. we investigated the effects of asc on dna cleavage by human topoisomerases i and ii. relaxation assays using supercoiled dna showed that asc stimulated double-stranded cleavage of dna by topoisomerase ii, but exerted only a very w ...200010874127
binding to dna and cytotoxic evaluation of ascididemin, the major alkaloid from the mediterranean ascidian cystodytes dellechiajei.the isolation of ascididemin from the mediterranean ascidian cystodytes dellechiajei is described. this alkaloid consists of a planar pentacyclic chromophore which was investigated for its dna-binding and cytotoxic properties. spectroscopic measurements provided evidence that the drug intercalates into dna. dnase i footprinting assays indicated that the binding of ascididemin to gc-rich sequences is favoured over binding to at-rich and mixed sequences. chemical probes were used to detect ligand- ...19957786398
epibiosis of oxygenic phototrophs containing chlorophylls a, b, c, and d on the colonial ascidian cystodytes dellechiajei.the external surfaces of marine animals are colonized by a wide variety of epibionts. here, we study the phototrophic epibiotic community attached to the colonial ascidian cystodytes dellechiajei collected in the mediterranean sea. epifluorescence microscopy analysis showed abundant filamentous cyanobacteria on the upper and basal parts of the ascidian that displayed autofluorescence, as well as some unicellular cyanobacteria, diatoms, and structures, which could belong to microscopic rhodophyte ...201120532497
sebastianines a and b, novel biologically active pyridoacridine alkaloids from the brazilian ascidian cystodytes dellechiajei.fractionation of the crude methanol extract of the ascidian cystodytes dellechiajei collected in brazil yielded two novel alkaloids, sebastianine a (1) and sebastianine b (2). the structures of both 1 and 2 were established by analysis of spectroscopic data, indicating an unprecedented ring system for both compounds, comprising a pyridoacridine system fused with a pyrrole unit in sebastianine a (1) and a pyridoacridine system fused with a pyrrolidine system condensed with alpha-hydroxyisovaleric ...200212126446
cystodytins d-i, new cytotoxic tetracyclic aromatic alkaloids from the okinawan marine tunicate cystodytes dellechiajei. 20041812214
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