Nematocidal thiocyanatins from a southern Australian marine sponge Oceanapia sp.

Investigations of a southern Australian marine sponge, Oceanapia sp., have yielded two new methyl branched bisthiocyanates, thiocyanatins D-1 (3a) and D-2 (3b), along with two new thiocarbamate thiocyanates, thiocyanatins E-l (4a) and E-2 (4b). The new thiocyanatins belong to a rare class of bioactive marine metabolite previously only represented by thiocyanatins A-C (1, 2a/b). Structures were assigned on the basis of detailed spectroscopic analysis, with comparisons to the known bisthiocyanate thiocyanatin A (1) and synthetic model compounds (5-7). The thiocyanatins exhibit potent nematocidal activity, and preliminary structure-activity relationship investigations have confirmed key characteristics of the thiocyanatin pharmacophore.

Structural and stereochemical revision of isocyanide and isothiocyanate amphilectenes from the Caribbean marine sponge Cribochalina sp.

The absolute stereochemistry of amphilectene metabolites from Cribochalina sp. has been revised by a detailed NMR spectroscopic study of the Mosher ester derivatives of a related alcohol. The relative stereochemistry of the previously described amphilectenes has been reinvestigated and reassigned on the basis of the X-ray structural analysis carried out on one of them. The structure of a new amphilectene metabolite, which is an isothiocyanato analogue is also presented. (c) 2005 Elsevier Ltd. All rights reserved.

(-)-echinobetaine A: Isolation, structure elucidation, synthesis, and SAR studies on a new nematocide from a southern Australian marine sponge, Echinodictyum sp.

A nematocidal agent present in a southern Australian marine sponge of the genus Echinodictyum has been isolated and identified by detailed spectroscopic analysis and total synthesis as the novel betaine (-)-echinobetaine A (6). Preliminary SAR investigations have been undertaken.

Spongosoritin A: A new polyketide from a Fijian marine sponge, Spongosorites sp.

A new polyketide, spongosoritin A, with a rare vinylagous alpha,beta-unsaturated gamma-lactone moiety was isolated from a Fijian marine sponge, Spongosorites sp., and the structure assigned by detailed spectroscopic analysis.

(+)-Echinobetaine B: isolation, structure elucidation, synthesis and preliminary SAR studies on a new nematocidal betaine from a southern Australian marine sponge, Echinodictyum sp.

The principle nematocidal agent present in a southern Australian marine sponge of the genus Echinodictyum has been isolated and identfied as the novel betaine (+)-echinobetaine B (6), and the structure assigned by spectroscopic analysis has been confirmed by total synthesis. Preliminary SAR conclusions are drawn from analysis of synthetic intermediates and the known marine metabolites zooanemonin (12) and norzooanemonin (13), and the new sponge metabolite norzooanemonin methyl ester (14). The latter compound is reported for the first time from a selection of Australian sponges, including an Axinyssa sp., a Niphates sp., an Axinella sp. and a Ptilocaulis sp.

Diversity of polyketide synthase genes from bacteria associated with the marine sponge Pseudoceratina clavata: culture-dependent and culture-independent approaches

Diverse ketosynthase (KS) genes were retrieved from the microbial community associated with the Great Barrier Reef sponge Pseudoceratina clavata. Bacterial isolation and metagenomic approaches were employed. Phylogenetic analysis of 16S rRNA of culturable sponge-associated bacterial communities comprised eight groups over four phyla. Ten KS domains were amplified from four genera of isolates and phylogenetics demonstrated that these KS domains were located in three clusters (actinobacterial, cyanobacterial and trans-AT type). Metagenomic DNA of the sponge microbial community was extracted to explore community KS genes by two approaches: direct amplification of KS domains and construction of fosmid libraries for KS domain screening. Five KS domains were retrieved from polymerase chain reaction (PCR) amplification using sponge metagenome DNA as template and five fosmid clones containing KS domains found using multiplex PCR screening. Analysis of selected polyketide synthase (PKS) from one fosmid showed that the PKS consists of two modules. Open reading frames located up- and downstream of the PKS displayed similarity with membrane synthesis-related proteins such as cardiolipin synthase. Metagenome approaches did not detect KS domains found in sponge isolates. All KS domains from both metagenome approaches formed a single cluster with KS domains originating from metagenomes derived from other sponge species from other geographical regions.

Biological fluorination from the sea : discovery of a SAM-dependent nucleophilic fluorinating enzyme from the marine-derived bacterium Streptomyces xinghaiensis NRRL B24674

We thank Prof. David O’Hagan and Dr Qingzhi Zhang (University of St Andrews, UK) for their helpful discussion and for providing the synthetic 50 -FDA sample. This work is supported by National Natural Science Foundation of China (No. 81503086), a starting funding (No. 20140520) from Tianjin University of Science & Technology, a research funding of “1000 Talents Plan” of Tianjin (to LM) and Foundation of Key Laboratory of Industrial Fermentation Microbiology of Ministry of Education and Tianjin Key Lab of Industrial Microbiology (No. 2015IM106)

Antibacterial activity of the marine sponge Ircinia Campana collected at Punta Uva Limón against Staphylococcus Aureus

The sponges are simple multicellularorganisms; they inhabit in marine environments from the polar seas to the tropical waterswhere they are more abundant. These species are exposed to large populations of microbes, reason that explains their complex morphological and cellular defense mechanism, which are used by these organisms to fight against pathogens. The purpose of this study was to evaluate the antibacterial activity of the marine sponge Ircinia campana, whichinhabits in the south of the Caribbean coast of Costa Rica against  Sthapylococcus aureus gram-positive bacteria. Sampleswere collected in Punta Uva in Limónduring July of 2007. The active compounds were obtainedby extraction with acetone (crude extract); and subsequently, chromatographic extracts were obtained using fractions 1:4 hexane: ethyl acetate. The antibacterial activities of the different fractions, including the  crude extract were tested.Our results suggest a zone of inhibition of 14.60 ±0.25 mm for the crude extract and18.70±0.25mm for the most active fraction separated by chromatography. The metabolite responsible for the antibacterial activity was isolated by High Performance Liquid Chromatography (HPLC)and preliminarily characterized through ultraviolet (UV) and infrared (IR) spectroscopy.

A spongin-boring alpha-proteobacterium is the etiological agent of disease in the Great Barrier Reef sponge Rhopaloeides odorabile

High levels of mortality in the Mediterranean bath sponge industry have raised concerns for the future of sponge farms. Healthy sponges feed predominantly on bacteria, and many harbour a wide diversity of inter- and extra-cellular symbiotic bacteria. Here we describe the first isolation and description of a pathogenic bacterium from an infected marine sponge. Microbiological examination of tissue necrosis in the Great Barrier Reef sponge Rhopaloeides odorabile resulted in isolation of the bacterial strain NW4327. Sponges infected with strain NW4327 exhibited high levels of external tissue necrosis, and the strain was re-isolated from infected sponges. A single morphotype, which had burrowed through the collagenous spongin fibres causing severe necrosis, was observed microscopically. Strain NW4327 was capable of degrading commercial preparations of azo-collagen, providing further evidence of its involvement in spongin fibre necrosis, Strain NW4327 disrupted the microbial community associated with R. odorabile and was able to infect and kill healthy sponge tissue. 16S rRNA sequence analysis revealed that strain NW4327 is a novel member of the alpha-proteobacteria.

Marine actinomycetes related to the 'Salinospora' group from the Great Barrier Reef sponge Pseudoceratina clavata

Ten strains identified as marine actinomycetes related to the 'Salinospora ' group previously reported only from marine sediments were isolated from the Great Barrier Reef marine sponge Pseudoceratina clavata. The relationship of the isolates to 'Salinospora' was confirmed by phylogenetic analysis of 16S rRNA gene sequences. Colony morphology and pigmentation, occurrence and position of spores, and salinity requirements for growth were all consistent with this relationship. Genes homologous to beta-ketosynthase, an enzyme forming part of a polyketide synthesis complex, were retrieved from these isolates; these genes shared homology with other Type I ketosynthase genes, and phylogenetic comparison with amino acid sequences derived from database beta-ketosynthase genes was consistent with the close relationship of these isolates to the actinomycetes. Primers based on 16S rRNA gene sequences and designed for targeting amplification of members of the 'Salinospora' group via polymerase chain reaction have been used to demonstrate occurrence of these actinomycetes within the sponge tissue. In vitro bioassays of extracts from the isolates for antibiotic activity demonstrated that these actinomycetes have the potential to inhibit other sponge symbionts in vivo, including both Gram-negative and Gram-positive bacteria.

The syntheses of the marine metabolites 3-bromoverongiaquinol and 5-monobromocavernicolin

An efficient synthesis of the marine metabolite 3-bromoverongiaquinol (1) and the first total synthesis of 5-monobromocavernicolin (2), both isolated from the marine sponge Aplysina cavernicola, have been described based on the 1,2 addition of the lithium enolate of N,O-bistrimethylsilylacetamide (BSA, 4) to 1,4-benzoquinone (3). Bromination and purification of the crude product on silica gel chromatography provided 3-bromoverongiaquinol (1) in 50% overall yield. Under alkaline conditions, the crude product of the bromination reaction was converted to 5-monobromocavernicolin (2) in 20% yield which was also obtained in 13% yield (25% yield based on recovered starting material) from 3-bromoverongiaquinol (1).

Cellular origin of chlorinated diketopiperazines in the dictyoceratid sponge Dysidea herbacea (Keller)

The tropical marine sponge Dysidea herbacea (Keller) contains the filamentous unicellular cyanobacterium Oscillatoria spongeliae (Schulze) Hauck as an endosymbiont, plus numerous bacteria, both intracellular and extracellular. Archaeocytes and choanocytes are the major sponge cell types present. Density gradient centrifugation of glutaraldehyde-fixed cells with Percoll as the support medium has been used to separate the cyanobacterial symbiont from the sponge cells on the basis of their differing densities. The protocol also has the advantage of separating broken from intact cells of O. spongeliae. The lighter cell preparations contain archaeocytes and choanocytes together with damaged cyanobacterial cells, whereas heavier cell preparations contain intact cyanobacterial cells, with less than 1% contamination by sponge cells. Gas chromatography/mass spectrometry analysis has revealed that the terpene spirodysin is concentrated in preparations containing archaeocytes and choanocytes, whereas nuclear magnetic resonance analysis of the symbiont cell preparations has shown that they usually contain the chlorinated diketopiperazines, dihydrodysamide C and didechlorodihydrodysamide C, which are the characteristic metabolites of the sponge/symbiont association. However, one symbiont preparation, partitioned by a second Percoll gradient, has been found to be devoid of chlorinated diketopiperazines. The capability to synthesize secondary metabolites may depend on the physiological state of the symbiont; alternatively, there may be two closely related cyanobacterial strains within the sponge tissue.

A sponge/dinoflagellate association in the haplosclerid sponge Haliclona sp.: cellular origin of cytotoxic alkaloids by Percoll density gradient fractionation

Light-microscopic and electron-microscopic studies of the tropical marine sponge Haliclona sp. (Or der: Haplosclerida Family: Haliclonidae) from Heron Island, Great Barrier Reef, have revealed that this sponge is characterized by the presence of dinoflagellates and by nematocysts. The dinoflagellates are 7-10 mu m in size, intracellular, and contain a pyrenoid with a single stalk, whereas the single chloroplast is branched, curved, and lacks grana. Mitochondria are present, and the nucleus is oval and has distinct chromosomal structure. The dinoflagellates are morphologically similar to Symbiodinium microadriaticum, the common intracellular symbiont of corals, although more detailed biochemical and molecular studies are required to provide a precise taxonomic assignment. The major sponge cell types found in Haliclona sp, are spongocytes, choanocytes, and archaeocytes; groups of dinoflagellates are enclosed within large vacuoles in the archaeocytes. The occurrence of dinoflagellates in marine sponges has previously been thought to be restricted to a small group of sponges including the excavating hadromerid sponges; the dinoflagellates in these sponges are usually referred to as symbionts. The role of the dinoflagellates present in Haliclona sp. as a genuine symbiotic partner requires experimental investigation. The sponge grows on coral substrates, from which it may acquire the nematocysts, and shows features, such as mucus production, which are typical of some excavating sponges. The cytotoxic alkaloids, haliclonacyclamines A and B, associated with Haliclona sp. are shown by Percoll density gradient fractionation to be localized within the sponge cells rather than the dinoflagellates. The ability to synthesize bioactive compounds such as the haliclonacyclamines may help Haliclona sp. to preserve its remarkable ecological niche.