Polybrominated Diphenyl Ethers: Structure Determination and Trends in Antibacterial Activity.

Antibacterial-guided fractionation of the Dictyoceratid sponges Lamellodysidea sp. and two samples of Dysidea granulosa yielded 14 polybrominated, diphenyl ethers including one new methoxy-containing compound (8). Their structures were elucidated by interpretation of spectroscopic data of the natural product and their methoxy derivatives. Most of the compounds showed strong antimicrobial activity with low- to sub-microgram mL(-1) minimum inhibitory concentrations against drug-susceptible and drug-resistant strains of Staphylococcus aureus and Enterococcus faecium, and two compounds inhibited Escherichia coli in a structure-dependent manner.

Mutremdamide A and koshikamides C-H, peptide inhibitors of HIV-1 entry from different Theonella species.

A new sulfated cyclic depsipeptide, termed mutremdamide A, and six new highly N-methylated peptides, termed koshikamides C-H, were isolated from different deep-water specimens of Theonella swinhoei and Theonella cupola. Their structures were determined using extensive 2D NMR, ESI, or CDESI and QTOF-MS/MS experiments and absolute configurations established by quantum mechanical calculations, advanced Marfey's method, and chiral HPLC. Mutremdamide A displays a rare 2-amino-3-(2-hydroxyphenyl)propanoic acid and a new N(delta)-carbamoyl-beta-sulfated asparagine. Koshikamides C-E are linear undecapeptides, and koshikamides F-H are 17-residue depsipeptides containing a 10-residue macrolactone. Koshikamides F and G differ from B and H in part by the presence of the conjugated unit 2-(3-amino-5-oxopyrrolidin-2-ylidene)propanoic acid. Cyclic koshikamides F and H inhibited HIV-1 entry at low micromolar concentrations while their linear counterparts were inactive. The Theonella collections studied here are distinguished by co-occurrence of mutremdamide A, koshikamides, and theonellamides, the combination of which appears to define a new Theonella chemotype that can be found in deeper waters.

Cinachyrella anatriaenilla sp. nov., a new tetillid sponge with microacanthoxeas from American Samoa in the South Pacific.

Several sponges from American Samoa, collected by the Coral Reef Research Foundation, Republic of Palau, were tentatively identified by one of us as Acanthotetilla cf seychellensis (Thomas 1973), due to the possession of relatively small acanthose oxeas, compared to those of other species of the genus Acanthotetilla Burton 1959. These sponges were later compared to Cinachyrella australiensis (Carter 1886), taking into account the lack of conspicuous spination on the acanthose oxeas and general features of spiculation and skeletal organisation. The specimens were later considered to represent a new species of the genus Cinachyrella Wilson 1925, after a careful comparison was made between the American Samoan specimens and C. australiensis which also contains small acanthose oxeas. Several recent molecular phylogenetic studies have confirmed the generic assignment of one of the American Samoan specimens as belonging to Cinachyrella. Cinachyrella anatriaenilla sp. nov., described herein, is the fifth of 40 Cinachyrella spp. that contain lightly spined microacanthoxeas.

Marine lake ecosystem dynamics illustrate ENSO variation in the tropical western Pacific.

Understanding El Niño/Southern Oscillation (ENSO) and its biological consequences is hindered by a lack of high-resolution, long-term data from the tropical western Pacific. We describe a preliminary, 6 year dataset that shows tightly coupled ENSO-related bio-physical dynamics in a seawater lake in Palau, Micronesia. The lake is more strongly stratified during La Niña than El Niño conditions, temperature anomalies in the lake co-vary strongly with the Niño 3.4 climate index, and the abundance of the dominant member of the pelagic community, an endemic subspecies of zooxanthellate jellyfish, is temperature associated. These results have broad relevance because the lake: (i) illustrates an ENSO signal that is partly obscured in surrounding semi-enclosed lagoon waters and, therefore, (ii) may provide a model system for studying the effects of climate change on community evolution and cnidarian-zooxanthellae symbioses, which (iii) should be traceable throughout the Holocene because the lake harbours a high quality sediment record; the sediment record should (iv) provide a sensitive and regionally unique record of Holocene climate relevant to predicting ENSO responses to future global climate change and, finally, (v) seawater lake ecosystems elsewhere in the Pacific may hold similar potential for past, present, and predictive measurements of climate variation and ecosystem response.