Michelle Kelly

Global Diversity of Sponges (Porifera)

With the completion of a single unified classification, the Systema Porifera (SP) and subsequent development of an online species database, the World Porifera Database (WPD), we are now equipped to provide a first comprehensive picture of the global biodiversity of the Porifera. An introductory overview of the four classes of the Porifera is followed by a description of the structure of our main source of data for this paper, the WPD. From this we extracted numbers of all ‘known’ sponges to date: the number of valid Recent sponges is established at 8,553, with the vast majority, 83%, belonging to the class Demospongiae. We also mapped for the first time the species richness of a comprehensive set of marine ecoregions of the world, data also extracted from the WPD. Perhaps not surprisingly, these distributions appear to show a strong bias towards collection and taxonomy efforts. Only when species richness is accumulated into large marine realms does a pattern emerge that is also recognized in many other marine animal groups: high numbers in tropical regions, lesser numbers in the colder parts of the world oceans. Preliminary similarity analysis of a matrix of species and marine ecoregions extracted from the WPD failed to yield a consistent hierarchical pattern of ecoregions into marine provinces. Global sponge diversity information is mostly generated in regional projects and resources: results obtained demonstrate that regional approaches to analytical biogeography are at present more likely to achieve insights into the biogeographic history of sponges than a global perspective, which appears currently too ambitious. We also review information on invasive sponges that might well have some influence on distribution patterns of the future.

Characterization of a Culturable Alphaproteobacterial Symbiont Common to Many Marine Sponges and Evidence for Vertical Transmission via Sponge Larvae

ABSTRACT A closely related group of alphaproteobacteria were found to be present in seven genera of marine sponges from several locations and were shown to be transferred between sponge generations through the larvae in one of these sponges. Isolates of the alphaproteobacterium were cultured from the sponges Axinella corrugata, Mycale laxissima, Monanchora unguifera, and Niphates digitalis from Key Largo, Florida; Didiscus oxeata and Monanchora unguifera from Discovery Bay, Jamaica; an Acanthostronglyophora sp. from Manado, Indonesia; and Microciona prolifera from the Cheasapeake Bay in Maryland. Isolates were very similar to each other on the basis of 16S rRNA gene sequence (>99% identity) and are closely related to Pseudovibrio denitrificans. The bacterium was never isolated from surrounding water samples and was cultured from larvae of M. laxissima, indicating that it is a vertically transmitted symbiont in this sponge. Denaturing gradient gel electrophoresis, 16S rRNA gene clone library analysis, and fluorescent in situ hybridization with probes specific to the alphaproteobacterium confirmed the presence of this bacterium in the M. laxissima larvae. The alphaproteobacterium was densely associated with the larvae rather than being evenly distributed throughout the mesohyl. This is the first report of the successful culture of a bacterial symbiont of a sponge that is transferred through the gametes.

Monitoring Bacterial Diversity of the Marine Sponge Ircinia strobilina upon Transfer into Aquaculture

ABSTRACT Marine sponges in the genus Ircinia are known to be good sources of secondary metabolites with biological activities. A major obstacle in the development of sponge-derived metabolites is the difficulty in ensuring an economic, sustainable supply of the metabolites. A promising strategy is the ex situ culture of sponges in closed or semiclosed aquaculture systems. In this study, the marine sponge Ircinia strobilina (order Dictyoceratida: family Irciniidae) was collected from the wild and maintained for a year in a recirculating aquaculture system. Microbiological and molecular community analyses were performed on freshly collected sponges and sponges maintained in aquaculture for 3 months and 9 months. Chemical analyses were performed on wild collected sponges and individuals maintained in aquaculture for 3 months and 1 year. Denaturing gradient gel electrophoresis was used to assess the complexity of and to monitor changes in the microbial communities associated with I. strobilina. Culture-based and molecular techniques showed an increase in the Bacteroidetes and Alpha- and Gammaproteobacteria components of the bacterial community in aquaculture. Populations affiliated with Beta- and Deltaproteobacteria, Clostridia, and Planctomycetes emerged in sponges maintained in aquaculture. The diversity of bacterial communities increased upon transfer into aquaculture.

12,34-Oxamanzamines, novel biocatalytic and natural products from manzamine producing Indo-Pacific sponges

ent-12,34-Oxamanzamines E (1) and F (2), as well as 12,34-oxamanzamine A (4) were isolated from three Indo-Pacific sponges and their structures were assigned on the basis of spectroscopic data. The biocatalytic transformation of ent-8-hydroxymanzamine A (3) to 2, using Nocardia sp. ATCC 21145 and Fusarium oxysporium ATCC 7601, has also been achieved. These compounds possess a novel ring system generated through a new ether bridge formed between carbons 12 and 34 of the typical manzamine structure. Ten heterotrophic bacterial isolates, including actinomycetes and α-proteobacteria, were isolated from one of these sponges in a preliminary effort to identify a possible microbial origin for these compounds. The potent activity of the manzamines against malaria and the AIDS OI pathogen, Mycobacterium tuberculosis, is also presented.

Anti-Cryptococcal and Nitric Oxide Synthase Inhibitory Imidazole Alkaloids from the Calcareous Sponge Leucetta cf chagosensis

Abstract Antifungal imidazole alkaloids were isolated from the Egyptian Red Sea sponge Leucetta cf chagosensis using HPLC. These compounds were the previously reported naamidine A, B, D and G and the unreported symmetric imidazole alkaloid naamine D. Naamine D possesses moderate antifungal and nitric oxide synthase inhibitory activity. The structure of naamine D was determined using 1D and 2D NMR experiments including 1H–15N HMBC and high resolution mass spectrometry.

Anti-infective Discorhabdins from a Deep-Water Alaskan Sponge of the Genus Latrunculia

Bioassay- and LC-MS-guided fractionation of a methanol extract from a new deep-water Alaskan sponge species of the genus Latrunculia resulted in the isolation of two new brominated pyrroloiminoquinones, dihydrodiscorhabdin B and discorhabdin Y (2), along with six known pyrroloiminoquinone alkaloids, discorhabdins A (3), C (4), E (5), and L (6), dihydrodiscorhabdin C (7), and the benzene derivative 8. Compounds 3, 4, and 7 exhibited anti-HCV activity, antimalarial activity, and selective antimicrobial activity. Although compounds 3 and 7 displayed potent and selective in vitro antiprotozoal activity, Plasmodium berghei-infected mice did not respond to these metabolites due to their toxicity in vivo.

Secondary metabolites from three Florida sponges with antidepressant activity.

Brominated indole alkaloids are a common class of metabolites reported from sponges of the order Verongida. Herein we report the isolation, structure determination, and activity of metabolites from three Florida sponges, namely, Verongula rigida (order Verongida, family Aplysinidae), Smenospongia aurea, and S. cerebriformis (order Dictyoceratida, family Thorectidae). All three species were investigated chemically, revealing similarities in secondary metabolites. Brominated compounds, as well as sesquiterpene quinones and hydroquinones, were identified from both V. rigida and S. aurea despite their apparent taxonomic differences at the ordinal level. Similar metabolites found in these distinct sponge species of two different genera provide evidence for a microbial origin of the metabolites. Isolated compounds were evaluated in the Porsolt forced swim test (FST) and the chick anxiety-depression continuum model. Among the isolated compounds, 5,6-dibromo- N,N-dimethyltryptamine ( 1) exhibited significant antidepressant-like action in the rodent FST model, while 5-bromo- N,N-dimethyltryptamine ( 2) caused significant reduction of locomotor activity indicative of a potential sedative action. The current study provides ample evidence that marine natural products with the diversity of brominated marine alkaloids will provide potential leads for antidepressant and anxiolytic drugs.

Antiviral and anticancer optimization studies of the DNA-binding marine natural product aaptamine

Aaptamine has potent cytotoxicity that may be explained by its ability to intercalate DNA. Aaptamine was evaluated for its ability to bind to DNA to validate DNA binding as the primary mechanism of cytotoxicity. Based on UV–vis absorbance titration data, the Kobs for aaptamine was 4.0 (±0.2) × 103 which was essentially equivalent to the known DNA intercalator N‐[2‐(diethylamino)ethyl]‐9‐aminoacridine‐4‐carboxamide. Semi‐synthetic core modifications were performed to improve the general structural diversity of known aaptamine analogs and vary its absorption characteristics. Overall, 26 aaptamine derivatives were synthesized which consisted of a simple homologous range of mono and di‐N‐alkylations as well as some 9‐O‐sulfonylation and bis‐O‐isoaaptamine dimer products. Each product was evaluated for activity in a variety of whole cell and viral assays including a unique solid tumor disk diffusion assay. Details of aaptamine’s DNA‐binding activity and its derivatives’ whole cell and viral assay results are discussed.

Antimalarial, antiviral, and antitoxoplasmosis norsesterterpene peroxide acids from the Red Sea sponge Diacarnus erythraeanus.

A new norsesterterpene acid, named muqubilone (1), along with the known sigmosceptrellin-B and muqubilin were isolated from the Red Sea sponge Diacarnus erythraeanus. The structure determination of 1 was based primarily on 1D and 2D NMR analyses. Sigmosceptrellin-B exhibits significant in vitro antimalarial activity against Plasmodium falciparum (D6 and W2 clones) with IC(50) values of 1200 and 3400 ng/mL, respectively. Muqubilin and 1 show in vitro antiviral activity against herpes simplex type 1 (HSV-1) with ED(50) values of 7.5 and 30 microg/mL, respectively. Muqubilin and sigmosceptrellin-B display potent in vitro activity against Toxoplasma gondii at a concentration of 0.1 microM without significant toxicity.

THE MANZAMINE ALKALOIDS

Publisher Summary The manzamine alkaloids are unique and viable, lead to the treatment of malaria, as well as other infectious or tropical parasitic diseases, based on their significant activity in animal models. In addition, the relatively wide range of biological activity for the manzamines in vitro raises the question that perhaps these molecules maybe broad-spectrum antiparasitic antibiotics generated by a sponge-associated microbe. The ecological relationship between the microbial communities and the sponge in the case of the manzamines is particularly intriguing because of the structural complexity of these alkaloids. In spite of the necessity of the β -carboline moiety for in vitro antimalarial activity, it has little effect on the antituberculosis activity in vitro , suggesting that different possible mechanisms of action are likely to exist. Few classes of alkaloids are as unique and intriguing as the manzamine class. The biological activity of the manzamines against infectious diseases, cancer, and inflammatory diseases, combined with their unusual structure, strongly suggests that these alkaloids will ultimately yield useful clinical candidates. In addition, the manzamine alkaloids are clearly a key to understanding the sophisticated, but poorly understood, ecological, and phylogenetic relationships between a diverse group of sponges and their associated microbial communities.