The Distribution and Antibacterial Activity of Marine Sponge-Associated Bacteria in the Aegean Sea and the Sea of Marmara, Turkey.

The distribution and antibacterial activities of bacteria isolated from fifty-five marine sponge samples collected from the Aegean Sea and the Sea of Marmara were investigated in the period between 2011 and 2013. The antibacterial activities of the methanolic extracts of marine sponge-associated bacteria tested against six pathogenic bacteria: Staphylococcus aureus SA1 and SA2, Brucella melitensis B37, Vibrio vulnificus GK23, Escherichia coli O157:H7 (ATCC 35150), and Salmonella enterica subsp. enterica serovar typhi (ATCC 167), using disk diffusion tests and minimum inhibitory concentration technique. The bacteria isolated from sponges and ambient seawater samples were identified using VITEK 2 Compact 30 automated microbial identification system. All bacterial extracts were exhibited antibacterial activity with various MIC values ranging from 7.8 mg/ mL to 1000 mg/mL against all pathogenic bacteria tested. The antibacterial efficacy rates found to be higher in the Aegean Sea than the Sea of Marmara samples. Fifty-five sponge samples belonging to fifteen species and host twenty-two bacterial species belonging to seven classes in two different marine areas at varying rates were detected. The most common sponge-associated bacterium was recorded as Sphingomonas paucimobilis and Bacillus cereus in the Aegean Sea and the Sea of Marmara, respectively. The composition and counts of the sponge-associated bacteria were found significantly higher than the free-living bacteria in the ambient sea water sampling points of both two marine areas. The presence of high antibacterial potential of sponge-related bacteria obtained in this study provided data for further studies on marine-derived antimicrobial agents, including the effects of environmental differences.

Chaotic genetic structure and past demographic expansion of the invasive gastropod Tritia neritea in its native range, the Mediterranean Sea.

To better predict population evolution of invasive species in introduced areas it is critical to identify and understand the mechanisms driving genetic diversity and structure in their native range. Here, we combined analyses of the mitochondrial COI gene and 11 microsatellite markers to investigate both past demographic history and contemporaneous genetic structure in the native area of the gastropod Tritia neritea, using Bayesian skyline plots (BSP), multivariate analyses and Bayesian clustering. The BSP framework revealed population expansions, dated after the last glacial maximum. The haplotype network revealed a strong geographic clustering. Multivariate analyses and Bayesian clustering highlighted the strong genetic structure at all scales, between the Black Sea and the Adriatic Sea, but also within basins. Within basins, a random pattern of genetic patchiness was observed, suggesting a superimposition of processes involving natural biological effects (no larval phase and thus limited larval dispersal) and putative anthropogenic transport of specimens. Contrary to the introduced area, no isolation-by-distance patterns were recovered in the Mediterranean or the Black Seas, highlighting different mechanisms at play on both native and introduced areas, triggering unknown consequences for species' evolutionary trajectories. These results of Tritia neritea populations on its native range highlight a mixture of ancient and recent processes, with the effects of paleoclimates and life history traits likely tangled with the effects of human-mediated dispersal.

Structural studies on Demospongiae sponges from Gökçeada Island in the Northern Aegean Sea.

The Demospongiae is the largest Class in the phylum Porifera (sponges). Most sponge species in the Class Demospongiae have a skeleton of siliceous spicules and/or protein spongin or both. The first aim of this study was to perform the morphological and structural characterization of the siliceous spicules of four species belonging to Class Demospongiae (Suberites domuncula, Axinella polypoides, Axinella damicornis and Agelas oroides) collected around Gökçeada Island-Turkey (Northern Aegean Sea). The characterizations were carried out using a combination of Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDX), Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Small Angle X-ray Scattering (SAXS) techniques. The sponge Chondrosia reniformis (Porifera, Demospongiae) lacks a structural skeleton of spicules or the spongin. It consists mainly of a collagenous tissue. The collagen with sponge origin is an important source in biomedical and pharmaceutical applications. The second aim of this study was to provide more information on the molecular structure of collagen of outer (ectosome) and inner (choanosome) regions of the Chondrosia reniformis using ATR-FTIR spectroscopy. Hierarchical clustering analysis (HCA) was also used for the discrimination of ATR-FTIR spectra of species.

Antiprotozoal Linear Furanosesterterpenoids from the Marine Sponge Ircinia oros.

Chemical investigation of the marine sponge Ircinia oros yielded four linear furanosesterterpenoids, including the known metabolites ircinin-1 (1) and ircinin-2 (2) and two new compounds, ircinialactam E (3) and ircinialactam F (4). Their chemical structures were elucidated by using a combination of [α]D, NMR, HRMS, and FT-IR spectroscopy. The absolute configuration of C-18 in compounds 1-3 was identified as R by electronic circular dichroism (ECD) spectroscopy coupled with time-dependent density functional theory calculations. Compounds 1-4 showed moderate leishmanicidal, trypanocidal, and antiplasmodial activities (IC50 values 28-130 µM). This is the second report of rare glycinyl lactam derivatives 3 and 4 from the genus Ircinia.

Marine natural products from the Turkish sponge Agelas oroides that inhibit the enoyl reductases from Plasmodium falciparum, Mycobacterium tuberculosis and Escherichia coli.

The type II fatty acid pathway (FAS-II) is a validated target for antimicrobial drug discovery. An activity-guided isolation procedure based on Plasmodium falciparum enoyl-ACP reductase (PfFabI) enzyme inhibition assay on the n-hexane-, the CHCl(3-) and the aq MeOH extracts of the Turkish marine sponge Agelas oroides yielded six pure metabolites [24-ethyl-cholest-5alpha-7-en-3-beta-ol (1), 4,5-dibromopyrrole-2-carboxylic acid methyl ester (2), 4,5-dibromopyrrole-2-carboxylic acid (3), (E)-oroidin (4), 3-amino-1-(2-aminoimidazoyl)-prop-1-ene (5), taurine (6)] and some minor, complex fatty acid mixtures (FAMA-FAMG). FAMA, consisting of a 1:2 mixture of (5Z,9Z)-5,9-tricosadienoic (7) and (5Z,9Z)-5,9-tetracosadienoic (8) acids, and FAMB composed of 8, (5Z,9Z)-5,9-pentacosadienoic (9) and (5Z,9Z)-5,9-hexacosadienoic (10) acids in approximately 3:3:2 ratio were the most active PfFabI inhibitory principles of the hexane extract (IC(50) values 0.35 microg/ml). (E)-Oroidin isolated as free base (4a) was identified as the active component of the CHCl(3) extract. Compound 4a was a more potent PfFabI inhibitor (IC(50) 0.30 microg/ml=0.77 microM) than the (E)-oroidin TFA salt (4b), the active and major component of the aq MeOH extract (IC(50) 5.0 microg/ml). Enzyme kinetic studies showed 4a to be an uncompetitive PfFabI inhibitor (K(i): 0.4+/-0.2 and 0.8+/-0.2 microM with respect to substrate and cofactor). In addition, FAMA and FAMD (mainly consisting of methyl-branched fatty acids) inhibited FabI of Mycobacterium tuberculosis (MtFabI, IC(50)s 9.4 and 8.2 microg/ml, respectively) and Escherichia coli (EcFabI, IC(50)s 0.5 and 0.07 microg/ml, respectively). The majority of the compounds exhibited in vitro antiplasmodial, as well as trypanocidal and leishmanicidal activities without cytotoxicity towards mammalian cells. This study represents the first marine metabolites that inhibit FabI, a clinically relevant enzyme target from the FAS-II pathway of several pathogenic microorganisms.