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ABSTRACTRoutine DNA barcoding with the chloroplast gene tufA identified novel records of an unknown and denuded (i.e. lacking branchlets) Caulerpaspecies previously reported from the Florida Middle Grounds. tufA barcoding not only confirmed the matching molecular identity of this taxon with several newly collected denuded specimens from shallow habitats of the Yucatán shelf, but also with a set of plumose specimens previously collected from mesophotic depths of the West Florida shelf and recorded as Caulerpa sertularioides. Sequencing of two additional, faster-evolving DNA markers, i.e. nuclear ITS and the newly tested chloroplast-encoded rpoA, each confirmed conspecificity of the above morphotypes and the molecular separation of the new taxon from C. sertularioidesand filiform species found in the region, namely C. cupressoidesf. denudataand C. fastigiata. In light of our sequencing results and review of the early taxonomic history of filiform Caulerpa, we propose the description of Caulerpa wysorii sp. nov. for this new species that exhibits two distinct morphotypes in currently available collections, i.e. filiform or plumose assimilators. We also subsume C. tongaensiswithin the broadly distributed C. fastigiata, whose lectotype is also designated herein. In addition to Caulerpa wysorii sp. nov., we discovered yet another unknown denuded species from the Campeche Banks represented by a single specimen thus far.

A new, cyclic carbonate eudesmane-type sesquiterpene, eudesmacarbonate (1), was isolated from marine filamentous cyanobacterial mats associated with apparent ingestion-related intoxications of captive bottlenose dolphins in the Florida Keys. Sequencing of 16S rDNA revealed that mats were composed of closely related Oscillatoriacean species including a previously undocumented species of Neolyngbya. The structure of 1was elucidated by (+)-HRESIMS, 1D and 2D NMR, single-crystal X-ray diffraction, and vibrational circular dichroism data. Toxicity of 1was assessed in the zebrafish embryo/larval model, and 1was found to exhibit effects qualitatively similar to those observed for the known neurotoxin brevetoxin-2 and consistent with neurobehavioral impairment.

Three related new alkylphenols, termed anaephenes A–C (1–3), containing different side chains, were isolated from an undescribed filamentous cyanobacterium (VPG 16-59) collected in Guam. Our 16S rDNA sequencing efforts indicated that VPG 16-59 is a member of the marine genus Hormoscilla(Oscillatoriales). The structures of anaephenes A–C (1–3) were elucidated by spectroscopic methods, and compounds assayed for growth inhibitory activity against prokaryotic and eukaryotic cell lines. Anaephene B (2), possessing a terminal alkyne, displayed moderate activity against Bacillus cereusand Staphylococcus aureuswith MIC values of 6.1 μg/mL. While 1and 3showed no pronounced activity in these assays, their structural features highlight the unusual biosynthetic capacity of this cyanobacterium and warrant further study.

Abstract:When placed in marine laboratory microcosm tanks, Syringoderma floridana(Syringodermataceae, Syringodermatales) described from Atlantic Florida, grew from the surface of bare rhodoliths collected from 55 to 85 m depth in the northwestern Gulf of Mexico following the 2010 Deepwater Horizonoil spill. A partial nuclear 28S large subunit rDNA sequence of S. floridanaepitype specimens from Jupiter, Palm Beach County, Florida, confirmed the molecular identity of this species, which had been reported from Atlantic Florida waters. Among the five species currently recognized in the genus Syringoderma, S. floridanais the only known subtropical species. The range of the species is here extended from Atlantic Florida to the northwestern, southeastern, and northeastern Gulf of Mexico. The taxonomic validity of the monospecific Microzonia, the only other genus in the Syringodermatales, was reassessed on the basis of publicly available sequence data (chloroplast-encoded rbcL and psaA, and nuclear 28S) and described morphological features. In all molecular analyses, Microzonia velutinais nested within specimens of Syringoderma. Microzoniahas nomenclatural priority over Syringoderma; thus, the latter is reduced to synonymy under Microzonia. New nomenclatural combinations are proposed.

SauvageT., PayriC., DraismaS.G.A., Prud′hommevanReineW.F., VerbruggenH., BeltonG.S., GurgelC.F.D., GabrielD., SherwoodA.R. andFredericqS. 2013. Molecular diversity of the Caulerpa racemosa–Caulerpa peltata complex (Caulerpaceae, Bryopsidales) in New Caledonia, with new Australasian records for C. racemosa var. cylindracea. Phycologia52: 6–13. DOI: 10.2216/11-116.1Molecular characterization (plastid-encoded tufA gene) of New Caledonian members of the Caulerpa racemosa–Caulerpa peltatacomplex identified five lineages, each possibly harboring multiple species-level entities. On a global scale, the complex encompassed six lineages, two of which were pantropical and the remainder seemingly were restricted to the Indo-Pacific basin. Caulerpa racemosavar. cylindracea, a fast-spreading introduced taxon in the Mediterranean Sea and the Canary Islands, was previously thought to be restricted to southwestern Australia; it was newly reported here for New Caledonia and several northern Australian locations, including the Great Barrier Reef.

Our ongoing efforts to explore the chemical space associated with marine cyanobacteria from coral reefs of Guam have yielded two new members of the anaenamide family of natural products, anaenamides C (3)and D (4). These compounds were isolated from a novel Hormoscillasp. (VPG16-58). Our phylogenetic profiling (16S rDNA) of this cyanobacterium indicated that VPG16-58 is taxonomically distinct from the previously reported producer of the anaephenes, VPG16-59 (Hormoscillasp.), and other previously documented species of the genus Hormoscilla. The planar structures of 3and 4were determined via spectroscopic methods, and absolute configurations of the α-hydroxy acids were assigned by enantioselective HPLC analysis. To address the requirement for sufficient material for testing, we first adapted our published linear synthetic approach for 1and 2to generate anaenoic acid (7), which served as a point for diversification, providing the primary amides 3and 4from synthetic intermediates 5and 6, respectively. The compounds were then tested for effects on HCT116 colon cancer cell viability and in an ARE-luciferase reporter gene assay for Nrf2 modulation using HEK293 human embryonic kidney cells. Our findings indicate that, in contrast to cytotoxic methyl esters 1and 2, the primary amides 3and 4activate the Nrf2 pathway at noncytotoxic concentrations. Overall, our data suggest that the anaenamide scaffold is tunable to produce differential biological outcomes.