Anticancer natural product from marine invertebrates

Background Antibiotic resistance is a growing problem that can be ameliorated by the discovery of novel drug candidates. Bacterial associates are often the source of pharmaceutically active natural products isolated from marine invertebrates, and thus, important targets for drug discovery. While the microbiomes of many marine organisms have been extensively studied, microbial communities from chemically-rich nudibranchs, marine invertebrates that often possess chemical defences, are relatively unknown. Methods We applied both culture-dependent and independent approaches to better understand the biochemical potential of microbial communities associated with nudibranchs. Gram-positive microorganisms isolated from nudibranchs collected in the Red Sea were screened for antibacterial and antitumor activity. To assess their biochemical potential, the isolates were screened for the presence of natural product biosynthetic gene clusters, including polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes, using PCR. The microbiomes of the nudibranchs were investigated by high-throughput sequencing of 16S rRNA amplicons. Results In screens against five model microorganisms, 51% of extracts displayed antimicrobial activity against more than one organism, and 19% exhibited antitumor activity against Ehrlich’s ascites carcinoma. Sixty-four percent of isolates contained PKS and NRPS genes, suggesting their genomes contain gene clusters for natural product biosynthesis. Thirty-five percent were positive for more than one class of biosynthetic gene. These strains were identified as belonging to the Firmicutes and Actinobacteria phyla via 16S rRNA gene sequencing. In addition, 16S rRNA community amplicon sequencing revealed all bacterial isolates were present in the uncultured host-associated microbiome, although they were a very small percentage of the total community. Taken together, these results indicate that bacteria associated with marine nudibranchs are potentially a rich source of bioactive compounds and natural product biosynthetic genes.

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The Distribution of Sterols and Stanols in the Tunicate Ciona Intestinalis

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400020142 ◽

1982 ◽

Vol 62 (1) ◽

pp. 117-123 ◽

Cited By ~ 10

Author(s):

R. J. Morris ◽

M. J. Mccartney ◽

Q. Bone

Keyword(s):

Natural Product ◽

Marine Invertebrates ◽

Wide Spectrum ◽

Packed Column ◽

Physiological Role ◽

Mass Spectral ◽

The Common ◽

Sterol Profile ◽

Liquid Chromatographic ◽

Microbiological Reduction

INTRODUCTIONUntil recently saturated sterols – stands – were not thought to play an active biochemical or physiological role in organisms. They were generally considered to be diagenetic products of the microbiological reduction of the common natural product Δ5sterols and as such have been reported in sediments (e.g. Gaskell & Eglinton, 1975).Prior to the regular use of capillary gas liquid chromatographic (GLC) and gas chromatographic-mass spectrometric (GC-MS) techniques the majority of sterol analyses had been performed on packed column GLC. It is now well known that in the analysis of some of the complex mixtures of sterols which commonly occur in the marine environment, the use of packed column GLC techniques alone is an inadequate procedure (e.g. Ballantine; Roberts & Morris, 1976; Ballantine et al. 1977). Certainly complete resolution of the sterol-stanol pairs cannot normally be achieved on packed columns and identification of the components within each peak has to be made by multiple mass spectral scans across each peak (Ballantine et al. 1976). With the advent of techniques with better resolving powers, significant amounts of natural product stands have been found in a wide spectrum of phyla including molluscs, sponges coelenterates, echinoderms, annelids and tunicates (Morris & Culkin, 1977 and references therein; Ballantine et al. 1976; Ballantine, Lavis & Morris, 1979, 1981; Voogt, 1976; Ballantine et al. 1977; Ballantine et al. 1978; Gupta et al. 1979). In some instances the stanols have been found to account for over 50% of the animals component sterols.As the sterol profile of marine invertebrates becomes better understood it is clear that stanols are important biochemical constituents of many of these organisms; but little is known of their significance in any biochemical or physiological role.

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Symbiotic Microbes from Marine Invertebrates: Driving a New Era of Natural Product Drug Discovery

Diversity ◽

10.3390/d9040049 ◽

2017 ◽

Vol 9 (4) ◽

pp. 49 ◽

Cited By ~ 14

Author(s):

Alix Blockley ◽

David Elliott ◽

Adam Roberts ◽

Michael Sweet

Keyword(s):

Drug Discovery ◽

Natural Product ◽

Marine Invertebrates ◽

New Era

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Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074768 ◽

1983 ◽

Vol 41 ◽

pp. 194-195

Author(s):

D. F. Blake ◽

L. F. Allard ◽

D. R. Peacor

Keyword(s):

High Resolution ◽

Marine Invertebrates ◽

Sea Urchins ◽

Structural Features ◽

Sea Stars ◽

High Resolution Tem ◽

Relationship Of ◽

The Relationship ◽

Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

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Aliphatic and Related Natural Product Chemistry

10.1039/9781847555564 ◽

1981 ◽

Keyword(s):

Natural Product ◽

Natural Product Chemistry ◽

Product Chemistry

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Synthetic studies toward inducamide C

Organic & Biomolecular Chemistry ◽

10.1039/d0ob01995j ◽

2021 ◽

Author(s):

Ardalan A. Nabi ◽

Lydia M. Scott ◽

Daniel P. Furkert ◽

Jonathan Sperry

Keyword(s):

Natural Product ◽

Structural Revision ◽

Synthetic Studies

The rare benzoxazepine ring in the alkaloid inducamide C is unstable and prone to rearrangement, indicating that structural revision of the natural product may be necessary.

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