Chemical structure of native and modified sulfated heterorhamnans from the green seaweed Gayralia brasiliensis and their cytotoxic effect on U87MG human glioma cells.

A water-soluble sulfated heterorhamnan (Gb1) was isolated from the green seaweed Gayralia brasiliensis and purified by ultrafiltration, yielding a homogeneous polysaccharide (Gb1r). Both fractions contained rhamnose, xylose, galacturonic and glucuronic acids, galactose, and glucose. Chemical and spectroscopic methods allowed the determination of Gb1 and Gb1r chemical structure. Their backbones were constituted by 3-, 2-, and 2,3-linked rhamnosyl units (1:0.49:0.13 and 1:0.58:0.17, respectively), which are unsulfated (13.5 and 14.6%), disulfated (16.6 and 17.8%) or monosulfated at C-2 (8 and 8.6%) and C-4 (24.5 and 23.4%). Gb1 was oversulfated giving rise to Gb1-OS, which presented ~2.5-fold higher content of disulfated rhamnosyl units than Gb1, as determined by methylation analyses and NMR spectroscopy. Gb1 and Gb1-OS potently reduced the viability of U87MG human glioblastoma cells. Gb1 caused cell cycle arrest in the G1 phase, increased annexin V-stained cells, and no DNA fragmentation, while Gb1-OS increased the percentage of cells in the S and G2 phases and the levels of fragmented DNA and cells double-stained with annexin V/propidium iodide, suggesting an apoptosis mechanism. The results suggest that the different effects of Gb1 and Gb1-OS were related to differences in the sulfate content and position of these groups along the polysaccharide chains.

Diversity and Ecology of Chlorophyta (Viridiplantae) Assemblages in Protected and Non-protected Sites in Deception Island (Antarctica, South Shetland Islands) Assessed Using an NGS Approach.

Assessment of the diversity of algal assemblages in Antarctica has until now largely relied on traditional microbiological culture approaches. Here we used DNA metabarcoding through high-throughput sequencing (HTS) to assess the uncultured algal diversity at two sites on Deception Island, Antarctica. The first was a relatively undisturbed site within an Antarctic Specially Protected Area (ASPA 140), and the second was a site heavily impacted by human visitation, the Whalers Bay historic site. We detected 65 distinct algal taxa, 50 from within ASPA 140 and 61 from Whalers Bay. Of these taxa, 46 were common to both sites, and 19 only occurred at one site. Algal richness was about six times greater than reported in previous studies using culture methods. A high proportion of DNA reads obtained was assigned to the highly invasive species Caulerpa webbiana at Whalers Bay, and the potentially pathogenic genus Desmodesmus was found at both sites. Our data demonstrate that important differences exist between these two protected and human-impacted sites on Deception Island in terms of algal diversity, richness, and abundance. The South Shetland Islands have experienced considerable effects of climate change in recent decades, while warming through geothermal activity on Deception Island itself makes this island one of the most vulnerable to colonization by non-native species. The detection of DNA of non-native taxa highlights concerns about how human impacts, which take place primarily through tourism and national research operations, may influence future biological colonization processes in Antarctica.

Occurrence, antifungal susceptibility, and virulence factors of opportunistic yeasts isolated from Brazilian beaches.

BACKGROUND: Opportunistic pathogenic yeast species are frequently associated with water habitats that have pollution sources of human or animal origin. Candida albicans has already been suggested as a faecal indicator microorganism for aquatic environments. OBJECTIVES: The goal of this study was to investigate the occurrence of C. albicans and other opportunistic yeasts in sand and seawater samples from beaches in Brazil to assess their correlation with Escherichia coli, and to characterise the pathogenic potential of the yeast isolates. METHODS: Opportunistic species (yeasts that grow at 37ºC) were isolated from sand and seawater samples from eight beaches in Brazil during the summer and the winter. Opportunistic yeast species were evaluated for their susceptibility to antifungal drugs, virulence factors, and the in vitro and in vivo biofilm formation. Strains were selected to carry out virulence tests using BALB/c mice. FINDINGS: Several water samples could be classified as inappropriate for primary contact recreation in relation to E. coli densities. C. albicans was isolated in low densities. Of the 144 opportunistic yeasts evaluated, 61% displayed resistance or dose-dependent sensitivity to at least one tested drug, and 40% produced proteinase. Strains of C. albicans and Kodamaea ohmeri exhibited the highest rates of adhesion to buccal epithelial cells. All the C. albicans strains that were tested were able to undergo morphogenesis and form a biofilm on catheter fragments in both in vitro and in vivo experiments. It was possible to confirm the pathogenic potential of three of these strains during the disseminated infection test. MAIN CONCLUSIONS: The identification of opportunistic yeast species in seawater and sand samples from Brazilian beaches suggest a potential risk to the health of people who use these environments for recreational purposes.

Occurrence, antifungal susceptibility, and virulence factors of opportunistic yeasts isolated from Brazilian beaches

BACKGROUND Opportunistic pathogenic yeast species are frequently associated with water habitats that have pollution sources of human or animal origin. Candida albicans has already been suggested as a faecal indicator microorganism for aquatic environments. OBJECTIVES The goal of this study was to investigate the occurrence of C. albicans and other opportunistic yeasts in sand and seawater samples from beaches in Brazil to assess their correlation with Escherichia coli, and to characterise the pathogenic potential of the yeast isolates. METHODS Opportunistic species (yeasts that grow at 37ºC) were isolated from sand and seawater samples from eight beaches in Brazil during the summer and the winter. Opportunistic yeast species were evaluated for their susceptibility to antifungal drugs, virulence factors, and the in vitro and in vivo biofilm formation. Strains were selected to carry out virulence tests using BALB/c mice. FINDINGS Several water samples could be classified as inappropriate for primary contact recreation in relation to E. coli densities. C. albicans was isolated in low densities. Of the 144 opportunistic yeasts evaluated, 61% displayed resistance or dose-dependent sensitivity to at least one tested drug, and 40% produced proteinase. Strains of C. albicans and Kodamaea ohmeri exhibited the highest rates of adhesion to buccal epithelial cells. All the C. albicans strains that were tested were able to undergo morphogenesis and form a biofilm on catheter fragments in both in vitro and in vivo experiments. It was possible to confirm the pathogenic potential of three of these strains during the disseminated infection test. MAIN CONCLUSIONS The identification of opportunistic yeast species in seawater and sand samples from Brazilian beaches suggest a potential risk to the health of people who use these environments for recreational purposes.

Yeasts from macroalgae and lichens that inhabit the South Shetland Islands, Antarctica.

Antarctic terrestrial ecosystems are largely dominated by lichens, while shallow coastal environments are mainly covered by macroalgae. The aim of this study was to isolate and to evaluate the diversity of yeasts in different species of macroalgae and lichens collected in South Shetland Islands, Antarctica. A total of 405 yeasts were recovered (205 from macroalgae and 200 from lichens). The yeast community from macroalgae was most diversity than the yeast community from lichen. The dominance index was similar for both substrates. A total of 24 taxa from macroalgae and 18 from lichens were identified, and only 5 were common to both substrates. Metschnikowia australis, Mrakia sp., Rhodotorula glacialis and Glaciozyma litorale were the most abundant yeasts in macroalgae and Cryptococcus victoriae, Rhodotorula laryngis, Rhodotorula arctica, Trichosporon sp. 1 and Mrakia sp. were the most abundant in lichens. Based on molecular and phylogenetic analyses, four yeast from macroalgae and six from lichens were considered potential new species. This is the first study to report the yeast communities from the Antarctic macroalgae Himantothallus grandifolius and lichen Ramalina terebrata. Results suggest that Antarctic phyco and lichensphere represent a huge substrate for cold-adapted yeasts and enhanced the knowledge of the microbiota from extreme environments.

Benthic marine algae from the insular areas of Paraná, Brazil: new database to support the conservation of marine ecosystems / Algas marinhas bentônicas de áreas insulares do Paraná, sul do Brasil: checklist, novas ocorrências para o Estado e implicações para a conservação

This study describes the diversity of benthic marine algae from insular areas of the southern Brazilian coast. Algal samples were collected between 2006 and 2010 during the winter and the summer seasons at three sites in the coastal waters of Paraná, Brazil: Ilha do Mel, Currais Archipelago and Ilha do Farol. The samples were collected along parallel transects on the coast. In this survey, Paraná marine phycoflora comprised 139 taxa (90 Rhodophyta, 27 Chlorophyta and 22 Phaeophyceae). Fifty-two species represent new records for the state, and 14 taxa are present at all sampling sites and in both seasons. Higher diversities of rhodophytes and chlorophytes were observed at Ilha do Mel, while phaeophytes were more diverse at Currais Archipelago. Lower algal diversity was observed at Ilha do Farol, a sampling station which is near an urban area. Ceramiaceae, Rhodomelaceae and Corallinaceae were dominant among Rhodophyta, Cladophoraceae and Ulvaceae among Chlorophyta, and Dictyotaceae and Sargassaceae among Phaeophyceae. Seasonal and spatial differences in species composition could be explained by the availability of consolidated substrate, water transparency and proximity to an urban area. Seaweed biodiversity from the Paraná coast also presents low species richness compared to other Brazilian states as a result of the shorter coastline, lower availability of rocky shores, and the location between estuarine systems (Paranaguá and Guaratuba Bays). These bays input a large amount of continental water, resulting in decreased salinity, high concentrations of suspended particulate matter and low transparency in the water column. Knowledge of seaweed diversity is essential for conservation studies. In addition, environmental monitoring programs undertaken during medium- to long-term seasonal changes could be improved to reflect changes detected through new records, the introduction of alien species in the area of interest, or even dominance of opportunistic species over other taxa. Therefore, a database able to support the monitoring of biodiversity is a fundamental step in detecting environmental impacts that could change seaweed biogeography, mainly in urbanized and harbor areas.

O presente estudo descreve a diversidade de algas marinhas bentônicas em áreas insulares da costa do Paraná, sul do Brasil. As amostras de algas foram coletadas entre 2006 e 2010 durante o inverno e o verão, em três locais: Ilha do Mel, Arquipélago de Currais e Ilha do Farol. A amostragem foi realizada ao longo de transectos paralelos à linha de costa e, na Ilha dos Currais, em diferentes profundidades. A ficoflora marinha paranaense é composta por 139 táxons (90 Rhodophyta, 27 Chlorophyta e 22 Phaeophyceae). Cinquenta e duas espécies são novas citações para o Estado do Paraná, e 14 táxons foram registrados em todos os locais estudados durante o verão e o inverno. Diferenças sazonais e espaciais na composição específica podem ser explicadas pela disponibilidade de substratos rochosos, transparência da água e proximidade com a área urbana. A maior diversidade de rodófitas e clorófitas foi observada na Ilha do Mel e a de feofíceas no Arquipélago de Currais. A menor diversidade de algas foi observada na Ilha do Farol, ponto amostral mais próximo a uma área urbana. Ceramiaceae, Rhodomelaceae e Corallinaceae foram dominantes entre Rhodophyta, Cladophoraceae e Ulvaceae entre Chlorophyta, e Dictyotaceae e Sargassaceae entre Phaeophyceae. A diversidade de algas marinhas bentônicas na costa do Paraná é menor quando comparada a outros estados brasileiros e isto está associado à menor extensão de sua linha de costa, menor disponibilidade de substratos consolidados para recrutamento e localização entre dois sistemas estuarinos (baías de Paranaguá e de Guaratuba). Os estuários aumentam consideravelmente o aporte de água continental, diminuindo a salinidade, elevando as concentrações de material particulado em suspensão e reduzindo a transparência da água. O conhecimento da diversidade algácea é fundamental para estudos de conservação, sendo que câmbios sazonais em médio e longo prazo podem estar relacionados a alterações ambientais. O indicador destas mudanças pode ser a detecção de novas ocorrências, espécies novas ou ainda introdução de espécies exóticas na área em questão, ou mesmo pela dominância de táxons oportunistas. Portanto, uma base de dados que sustente um monitoramento da biodiversidade é relevante por detectar impactos que podem alterar padrões biogeográficos das comunidades de macroalgas, principalmente em regiões com influência de atividades antrópicas, como as zonas urbanas ou áreas portuárias.

Diversity and bioprospecting of fungal communities associated with endemic and cold-adapted macroalgae in Antarctica.

We surveyed the distribution and diversity of fungi associated with eight macroalgae from Antarctica and their capability to produce bioactive compounds. The collections yielded 148 fungal isolates, which were identified using molecular methods as belonging to 21 genera and 50 taxa. The most frequent taxa were Geomyces species (sp.), Penicillium sp. and Metschnikowia australis. Seven fungal isolates associated with the endemic Antarctic macroalgae Monostroma hariotii (Chlorophyte) displayed high internal transcribed spacer sequences similarities with the psychrophilic pathogenic fungus Geomyces destructans. Thirty-three fungal singletons (66%) were identified, representing rare components of the fungal communities. The fungal communities displayed high diversity, richness and dominance indices; however, rarefaction curves indicated that not all of the fungal diversity present was recovered. Penicillium sp. UFMGCB 6034 and Penicillium sp. UFMGCB 6120, recovered from the endemic species Palmaria decipiens (Rhodophyte) and M. hariotii, respectively, yielded extracts with high and selective antifungal and/or trypanocidal activities, in which a preliminary spectral analysis using proton nuclear magnetic resonance spectroscopy indicated the presence of highly functionalised aromatic compounds. These results suggest that the endemic and cold-adapted macroalgae of Antarctica shelter a rich, diversity and complex fungal communities consisting of a few dominant indigenous or mesophilic cold-adapted species, and a large number of rare and/or endemic taxa, which may provide an interesting model of algal-fungal interactions under extreme conditions as well as a potential source of bioactive compounds.

Seaweed cultivation on the Southern and Southeastern Brazilian Coast

Seaweeds are used directly as food or applied indirectly as texturing agents with gelling and thickening properties (carrageenan, agar and alginates) in many industries. They can also be used as fertilizers, animal feed, biomass for fuel, cosmetics and a source of pharmaceuticals, among other applications. The aquaculture of macroalgae is an alternative for producing raw material. Brazil has a coastline with numerous locations suitable for this endeavor. However, despite the known economical and social relevance of seaweed cultivation, Brazilians do not have tradition of using edible seaweeds. In general, the raw material for indirect use (e.g., as a texturing agent) is imported. Consequently, seaweed aquaculture is still incipient in Brazil. This contribution presents data and information about macroalgae cultivation on commercial and experimental scales performed on the Southern and Southeastern Brazilian Coastline, as well as a brief overview of research related to some species cultivated in the last decade.

Chemical structure and antiviral activity of the sulfated heterorhamnan isolated from the green seaweed Gayralia oxysperma.

A homogeneous sulfated heterorhamnan was obtained by aqueous extraction, then by ultrafiltration from the green seaweed Gayralia oxysperma. Besides alpha-L-rhamnose it contains glucuronic and galacturonic acids, xylose and glucose. The structure was established by methylation analyses of the carboxyl-reduced, carboxyl-reduced/desulfated, carboxyl-reduced/Smith-degraded, and carboxyl-reduced/Smith-degraded/desulfated products and 1D, 2D NMR spectroscopy analyses. The heterorhamnan backbone is constituted by 3- and 2-linked rhamnosyl units (1.00:0.80), the latter being approximately 50% substituted at C-3 by side chains containing 2-sulfated glucuronic and galacturonic acids and xylosyl units. The 3- and 2-linked rhamnosyl units are unsulfated (20%), disulfated (16%), and mostly monosulfated at C-2 (27%) and C-4 (37%). The branched and sulfated heterorhamnan had high and specific activity against herpes simplex virus.