Phylogenetic Diversity of Sponge-Associated Fungi from the Caribbean and the Pacific of Panama and Their In Vitro Effect on Angiotensin and Endothelin Receptors.

Fungi occupy an important ecological niche in the marine environment, and marine fungi possess an immense biotechnological potential. This study documents the fungal diversity associated with 39 species of sponges and determines their potential to produce secondary metabolites capable of interacting with mammalian G-protein-coupled receptors involved in blood pressure regulation. Total genomic DNA was extracted from 563 representative fungal strains obtained from marine sponges collected by SCUBA from the Caribbean and the Pacific regions of Panama. A total of 194 operational taxonomic units were found with 58% represented by singletons based on the internal transcribed spacer (ITS) and partial large subunit (LSU) rDNA regions. Marine sponges were highly dominated by Ascomycota fungi (95.6%) and represented by two major classes, Sordariomycetes and Dothideomycetes. Rarefaction curves showed no saturation, indicating that further efforts are needed to reveal the entire diversity at this site. Several unique clades were found during phylogenetic analysis with the highest diversity of unique clades in the order Pleosporales. From the 65 cultures tested to determine their in vitro effect on angiotensin and endothelin receptors, the extracts of Fusarium sp. and Phoma sp. blocked the activation of these receptors by more than 50% of the control and seven others inhibited between 30 and 45%. Our results indicate that marine sponges from Panama are a "hot spot" of fungal diversity as well as a rich resource for capturing, cataloguing, and assessing the pharmacological potential of substances present in previously undiscovered fungi associated with marine sponges.

Phylogeny and morphology of dematiaceous freshwater microfungi from Perú.

A survey of freshwater ascomycetes conducted along an elevational gradient in Perú in the Districts of Cusco, Junín, and Madre de Dios yielded specimens of Cancellidium applanatum, Cordana abramovii, Sporoschisma juvenile, S. uniseptatum, and S. saccardoi. With the exception of S. saccardoi, these are new records for Perú. Molecular data was generated for three previously unsequenced species: Cancellidium applanatum, Cordana abramovii and Sporoschisma saccardoi. These taxa are reported herein from the neotropics with an accompanying phylogeny based on partial 28S nuclear ribosomal large-subunit sequence data. The sexual morph of S. saccardoi has previously been linked to Melanochaeta hemipsila through cultural studies. Molecular data from ascospores and conidia of M. hemipsila and S. saccardoi, respectively, were used to demonstrate a genetic connection of the sexual and asexual morphs of these fungi for the first time, resulting in the new combination Sporoschisma hemipsila being made.

New species and new records of freshwater ascomycetes from Brazil and Costa Rica.

During independent surveys for freshwater ascomycetes in Brazil and Costa Rica, two new species, Torrentispora pilosa and Vertexicola ascoliberatus, and nine previously described species were recovered. Among the described species, Annulatascus biatriisporus, Anthostomella aquatica, Tamsiniella labiosa and Torrentispora crassiparietis are reported for the first time from the western hemisphere, Aniptodera chesapeakensis, Chaetosphaeria lignomollis and Jahnula seychellensis are new records for South America and Annulatascus velatisporus and Ophioceras venezuelensis are reported for the first time for Brazil. The description of the genus Torrentispora is emended to accommodate T. pilosa. The new species are described and illustrated and a brief description is provided for all new records.

Fluorescence correlation spectroscopy in drug discovery: study of Alexa532-endothelin 1 binding to the endothelin ETA receptor to describe the pharmacological profile of natural products.

Fluorescence correlation spectroscopy and the newly synthesized Alexa532-ET1 were used to study the dynamics of the endothelin ET(A) receptor-ligand complex alone and under the influence of a semisynthetic selective antagonist and a fungal extract on living A10 cells. Dose-dependent increase of inositol phosphate production was seen for Alexa532-ET1, and its binding was reduced to 8% by the selective endothelin ET(A) antagonist BQ-123, confirming the specific binding of Alexa532-ET1 to the endothelin ET(A) receptor. Two different lateral mobilities of the receptor-ligand complexes within the cell membrane were found allowing the discrimination of different states for this complex. BQ-123 showed a strong binding affinity to the "inactive" receptor state characterized by the slow diffusion time constant. A similar effect was observed for the fungal extract, which completely displaced Alexa532-ET1 from its binding to the "inactive" receptor state. These findings suggest that both BQ-123 and the fungal extract act as inverse agonists.

Three new genera representing novel lineages of Sordariomycetidae (Sordariomycetes, Ascomycota) from tropical freshwater habitats in Costa Rica.

Three new genera are established in the Sordariomycetidae based on morphological and molecular data (SSU and LSU nrDNA) to accommodate five ascomycete species collected from submerged woody debris in freshwater habitats from Costa Rica. The genus Bullimyces contains three new species, B. communis, B. costaricensis and B. aurisporus. Bullimyces is characterized by globose to subglobose, membranous, black, ostiolate ascomata; deliquescent, hyaline, globose cells that fill the center of the centrum; unitunicate asci that deliquesce early in some species; and septate, thick-walled ascospores with or without gelatinous sheaths or appendages. Bullimyces species form a well supported clade with 100% bootstrap support, but the position of the genus in the Sordariomycetidae remains unclear. The second genus, Riomyces, is represented by a single species, R. rotundus. Riomyces is characterized by globose to subglobose, membranous, black, ostiolate ascomata, unitunicate, cylindrical asci, hyaline, globose cells that fill the hamathecium and septate, thick-walled ascospores with a gelatinous sheath. Although Riomyces is morphologically similar to Bullimyces, the two genera did not group together with support in any analysis. The third genus, Hydromelitis, is represented by a single species, H. pulchella. Hydromelitis is characterized by pyriform, membranous, black, ostiolate ascomata, unitunicate asci lacking an apical structure, simple, thin-walled, septate paraphyses and hyaline to golden yellow, multiseptate, thick-walled ascospores with a gelatinous sheath. Bullimyces, Riomyces and Hydromelitis were nested within an unsupported clade consisting of members of the Ophiostomatales, Magnaporthales and freshwater Annulatacaceae sensu lato and sensu stricto.

Freshwater ascomycetes: Natipusillaceae, a new family of tropical fungi, including Natipusilla bellaspora sp. nov. from the Peruvian Amazon.

A new ascomycete species, Natipusilla bellaspora, collected from submerged woody debris in a freshwater stream at Los Amigos Biological Station, Madre De Dios in the Peruvian Amazon is described and illustrated. This fungus is characterized by small, globose to subglobose, hyaline ascomata; small, globose to subglobose, eight-spored fissitunicate asci; one-septate, multiguttulate ascospores with two different gelatinous sheaths, an outer amorphous sheath that enlarges in water and an inner sheath that has a distinctive persistent shape and is attached to the ascospore apex. Morphologically N. bellaspora differs from other Natipusilla species in having larger ascospores and two ascospore sheaths. A second Natipusilla species, N. limonensis, is reported for the first time from Peru. Based on the unique morphological characters of taxa in Natipusilla and results of previous molecular phylogenetic analyses with other members of the Dothideomycetes, we establish Natipusillaceae fam. nov. for this unique tropical freshwater clade.

Lucidascocarpa pulchella, a new ascomycete genus and species from freshwater habitats in the American tropics.

A new fungus collected from submerged wood in Costa Rica and Ecuador has ascostromatic ascomata with fissitunicate asci and lacks pseudoparaphyses, characters that place it in the Dothideaceae (Dothideales). It is unusual in the order because it has white ascomata. Based on other morphological characters however this fungus could not be accommodated in any existing genus in the Dothideaceae and it is described herein as a new genus and species, Lucidascocarpa pulchella. These morphological features are characteristic of L. pulchella: ascomata glistening, white, each with a long, periphysate neck; a membranous peridium composed of 5-7 thin-walled, hyaline cells; pseudoparaphyses absent; asci fissitunicate, clavate, eight-spored; ascospores seven-septate, hyaline, multiguttulate, verruculose, surrounded by a large, regular, gelatinous sheath.

Megalohypha, a new genus in the Jahnulales from aquatic habitats in the tropics.

A new fungus collected from submerged wood in tropical forest streams in Panama and Thailand is described as a new genus and species in the Jahnulales. This fungus, Megalohypha aqua-dulces, is described based on ascospore morphology, which differs substantially from that of the other genera in the Jahnulales. It has these morphological features: ascomata hyaline, translucent, with subtending, wide, brown, septate, stoloniferous hyphae; peridium of large, thin-walled cells; hamathecium of septate pseudoparaphyses; asci clavate, fissitunicate, 8-spored; and ascospores 1-septate, brown, rough-walled, with longitudinal sulcate striations. An interesting feature of Megalohypha aqua-dulces, which it shares with some other taxa in Jahnulales, is the presence of both sessile and stalked fruiting bodies. In addition, the stalks have morphology that consists of a wide hypha with a narrower hypha apparently enclosed within and the stalks are strongly constricted at the septa.

Ophiocerins A-D and ophioceric acid: tetrahydropyran derivatives and an africane sesquiterpenoid from the freshwater aquatic fungus Ophioceras venezuelense.

Four new tetrahydropyran derivatives called ophiocerins A-D (1-4) and a new africane sesquiterpenoid (ophioceric acid; 5) have been isolated from cultures of the aquatic fungus Ophioceras venezuelense, together with the known compound regiolone. The structures and relative stereochemistry of these compounds were determined by analysis of 1D and 2D NMR data, while absolute stereochemical assignments for 1-4 were proposed by application of the exciton chirality CD method.