Resumo em Inglês:

Qualitative and quantitative studies of mycosporine-like amino acids (MAAs) in three species of the genus Gracilaria Greville (G. birdiae, G. domingensis and G. tenuistipitata) were performed. A simple and efficient extraction procedure based on ethanol was described. HPLC, UV and mass spectrometry experiments revealed different profiles between extracts obtained from one species cultivated in the laboratory (G. tenuistipitata) and two species collected in their natural environment (G. birdiae and G. domingensis). The levels detected in the latter two species were approximately 150 times higher than in the species cultivated in vitro. This study revealed that G. birdiae and G. domingensis present a potential source for economical exploration of MAAs.

Resumo em Inglês:

Dolabelladienotriol is a product extracted from the brown marine alga Dictyota pfaffii from Brazil that has been shown to have antiviral activity and low cytotoxicity. Our studies have evaluated the acute toxicity of dolabelladienotriol in BALB/c mice for ten days after administration of a single dose. Among the parameters considered were behavior, weight, biochemical and histological analyses of blood samples taken at three different times (Bs.0, Bs.1 and Bs.2) and optical microscopic examination of organs like liver, kidney, stomach and small intestine. Mice deaths were not observed at any dose during the ten day period. There were some changes in the biochemical analysis results for urea nitrogen (BUN) and alanine aminotransferase (ALT), but the changes were not significantly different from the reference levels of the animals before administration of the substance. Histological analyses of tissues were very similar for all animals. The alterations in liver and kidney tissues did not affect the animals´ behavior at any concentration, not even at 50 mg/kg, where the most significant changes in tissues were seen. This study indicates that dolabelladienotriol has low toxicity in administered dose range.

Resumo em Inglês:

Dictyotaceae are a rich source of secondary metabolites, especially terpenes. These natural products have been studied for their bioactivity for human and for their ecological role in nature. The present work highlights de diversity of the Dictyotaceae terpenes, emphasizing their bioactivities and the biogeography of their sources. The sesquiterpenes are found in Padina, Dictyopteris and Taonia. Although Dictyopteris and Padina can be found in all oceans, Taonia has a more restricted distribution. Diterpenes of mixed origin have been reported in Lobophora, Taonia and Stypopodium. Stypopodium is a typically tropical and warm temperate genus. Diterpenes with the spatane and seco-spatanes skeletons are known from Spatoglossum, Stoechospermum and Rugulopteryx. Spatoglossum is distributed over all the tropical marine world. Stoechospermum is known to occur in the Indian Ocean and Rugulopteryx is distributed mainly in Asia and on the Pacific Coast of Australia. The genus Dictyota contains diterpenes as the major metabolite and are present in all oceans, reaching even the cold temperate regions of northern and southern hemispheres. The terpenoids from Dictyotaceae exhibit bioactivities such as inhibition of herbivores and antifungal, cytotoxic, antibiotic, anti-inflammatory, insecticidal and antiviral activities.

Resumo em Inglês:

A sulfated fucan from Laminaria abyssalis marine alga prevented the interaction of HTLV-1 particles, purified from the MT-2 cell line, with HeLa cells. The infection obtained using a concentrated virus suspension was detected only by amplification of the newly synthesized HTLV-1 proviral cDNA by the nested-polymerase chain reaction (PCR). The sulfated polysaccharide was not toxic to the cells at a concentration of 100 µg/mL and prevented infection by the viral particles when added to the cell monolayers. The proviral cDNA was only detected when the sulfated polysaccharide was added to the cells three hours post-infection, indicating that the inhibitory activity occurred in the initial stages of virus-cell interaction. Our results demonstrate, for the first time, the ability of a sulfated fucan from marine algae to inhibit virus transmission through free virus particles.

Resumo em Inglês:

The effect of a Brazilian algae extract and also a mixture of two secodolastane diterpenes (linearol/isolinearol) that were isolated from the marine brown alga Canistrocarpus cervicornis were evaluated against biological activities of Lachesis muta snake venom. In vitro assays showed that the crude extract and the diterpenes were able to inhibit the clotting and proteolytic activity induced by L. muta crude venom, but not the hemolytic activity. However, only the diterpenes inhibited the hemolysis caused by a purified phospholipase A2 previously isolated from L. muta venom, denoted LM-PLA2-I. Interestingly, the crude algal extract and the diterpenes were able to protect mice from hemorrhage induced by L. muta venom. Thus, we may conclude that marine algae are rich and powerful sources of molecules that may be used against L. muta accidents in order to improve treatment of envenomation by this snake.

Resumo em Inglês:

The development of new anti-cancer drugs of algal origin represents one of the least explored frontiers in medicinal chemistry. In this regard, the diversity of micro- and macroalgae found in Brazilian coastal waters can be viewed as a largely untapped natural resource. In this report, we describe a comparative study on the cytotoxic properties of extracts obtained from the Laurencia complex: Laurencia aldingensis, L. catarinensis, L. dendroidea, L. intricata, L. translucida, L. sp, and Palisada flagellifera. All of these species were collected in the coastal waters of the State of Espírito Santo, Brazil. Four out of the twelve samples initially investigated were found to show significant levels of toxicity towards a model tumor cell line (human uterine sarcoma, MES-SA). The highest levels of cytotoxicity were typically associated with non-polar (hexane) algal extracts, while the lowest levels of cytotoxicity were found with the corresponding polar (methanol) extracts. In this report, we also describe a biological model currently in development that will not only facilitate the search for new anti-cancer drug candidates of algal origin, but also permit the identification of compounds capable of inducing the destruction of multi-drug resistant tumors with greater efficiency than the pharmaceuticals currently in clinical use.

Resumo em Inglês:

Brown, red and green algae from the Southeastern coast of Brazil were successively extracted with chloroform/methanol 2:1 and 1:2 (v/v). The crude lipid extract was partitioned according to Folch and the lower phase enriched in glycolipids was fractionated on a silica gel column chromatography eluted with chloroform, acetone and methanol. Three major orcinol-reactive bands present in the acetone and methanol fractions were detected by thin-layer chromatography with chromatographic mobilities corresponding to sulfoglycolipids and glycosyldiacylglycerols. These fractions exhibited potent antiviral activity against HSV-1-ACVs and HSV-1-ACVr and present low toxicity for cell cultures. Purification and identification of these bioactive glycolipids will be necessary in order to elucidate their primary structures and mechanism of action.

Resumo em Inglês:

Two known sesquiterpenes (1R*,2S*,3R*,5S*,8S*,9R*)-2,3,5,9-tetramethyltricyclo[6.3.0.0(1,5)]undecan-2-ol and (1S*,2S*,3S*,5S*,8S*,9S*)-2,3,5,9-tetramethyltricyclo-[6.3.0.0(1,5)]undecan-2-ol were isolated for the first time from the essential oil of the red seaweed Laurencia dendroidea collected in the Brazilian coast. These compounds were not active against eight bacteria strains and the yeast Candida albicans, but showed some antioxidant activity. Both compounds were also found in other seaweed species showing that they are not exclusive taxonomic markers to the genus Laurencia.

Resumo em Inglês:

Effects of the interaction of irradiance and nutrient levels on growth and contents of photosynthetic pigments, carotenoids and proteins in Gracilaria domingensis (Kütz.) Sonder ex Dickie (Gracilariales, Rhodophyta) were investigated experimentally. Nutrient availability provided by dilutions of the nutrient solution of von Stosch (25 and 50%, which corresponded to nitrate concentrations of 125 and 250 μmol, respectively) and two photon flux densities [low PFD (50±5) and high PFD (100±5) μmol photons.m-2.s-1] were tested. Growth rates of G. domingensis were stimulated by high PFD. The interaction between high nutrient availability (50% VSES) and high PFD stimulated the accumulation of total soluble protein. Phycobiliprotein concentrations (phycoerythrin, phycocyanin, and allophycocyanin) and carotenoid contents were influenced by irradiance levels. Phycobiliprotein concentrations were higher at low PFD and high irradiances stimulated carotenoid accumulation. These results reflect the function of these pigments in photoprotection and the acclimation of G. domingensis to changes in irradiance levels. Our results indicate that light is a limiting factor for G. domingensis growth, that variations in phycobiliprotein contents under different irradiance levels are related to photoacclimation process, and that higher carotenoid contents at high irradiances are due to a photoprotection mechanism.

Resumo em Inglês:

The exploitation of seaweeds in Chile has been carried out for more than 60 years. More recently, seaweeds have been used for the production of alginate, agar and carrageenan, agricultural fertilizers and industrial aquaculture (feed for abalone and sea urchins), increasing the added value of this natural resource. In the Magellan Region (56ºS), the giant kelp Macrocystis pyrifera (L.) C. Agardh presents the most extensive kelp forest, reaching a biomass of approximately 12 kg.m-2. Recent studies have shown potential benefits from adding M. pyrifera- derived flour to salmonid feed. Research is currently underway to evaluate the useof brown algae-derived products for marine aquaculture feed of Oncorhynchus mykiss in tanks. There was no apparent adverse effect on the evaluated parameters that can be attributed to the incorporation of M. pyrifera meal in the diets fed to salmonids. Even when the control diet had numerically the best performance in zootechnical terms, the analysis of variance of all parameters evaluated showed no significant differences with regard to diets containing M. pyrifera meal. These results demonstrated that seaweed meal has important benefits for animal health and nutrition that could be applied or tested in other marine organisms of commercial importance.

Resumo em Inglês:

In Brazil, the Laurencia complex is represented by twenty taxa: Laurencia s.s. with twelve species, Palisada with four species (including Chondrophycus furcatus now that the proposal of its transference to Palisada is in process), and Osmundea and Yuzurua with two species each. The majority of the Brazilian species of the Laurencia complex have been phylogenetically analyzed by 54 rbcL sequences, including five other Rhodomelacean species as outgroups. The analysis showed that the Laurencia complex is monophyletic with high posterior probability value. The complex was separated into five clades, corresponding to the genera: Chondrophycus, Laurencia, Osmundea, Palisada, and Yuzurua. A bibliographical survey of the terpenoids produced by Brazilian species showed that only six species of Laurencia and five of Palisada (including C. furcatcus) have been submitted to chemical analysis with 48 terpenoids (47 sesquiterpenes and one triterpene) isolated. No diterpenes were found. Of the total, 23 sesquiterpenes belong to the bisabolane class and eighteen to the chamigrene type, whose biochemical precursor is bisabolane, two are derived from lauranes and four are triquinols. Despite the considerable number of known terpenes and their ecological and pharmacological importance, few experimental biological studies have been performed. In this review, only bioactivities related to human health were considered.

Resumo em Inglês:

Astaxanthin (ASTA) is a pinkish-orange carotenoid produced by microalgae, but also commonly found in shrimp, lobster and salmon, which accumulate ASTA from the aquatic food chain. Numerous studies have addressed the benefits of ASTA for human health, including the inhibition of LDL oxidation, UV-photoprotection and prophylaxis of bacterial stomach ulcers. ASTA is recognized as a powerful scavenger of reactive oxygen species (ROS), especially those involved in lipid peroxidation. Both aerobic and anaerobic exercise are closely related to overproduction of ROS in muscle tissue. Post-exercise inflammatory processes can even exacerbate the oxidative stress imposed by exercise. Thus, ASTA is suggested here as a putative nutritional alternative/coadjutant for antioxidant therapy to afford additional protection to muscle tissues against oxidative damage induced by exercise, as well as for an (overall) integrative redox re-balance and general human health.

Resumo em Inglês:

The resistance of pathogens to commonly used antibiotics has enhanced morbidity and mortality and has triggered the search for new drugs. Several species of the red alga genus Laurencia are very interesting candidates as potential sources of natural products with pharmaceutical activity because they are known to produce a wide range of chemically interesting halogenated secondary metabolites. This is an initial report of the antifungal activities of the secondary metabolites of five species of Laurencia, collected in the state of Espírito Santo, against three strains of pathogenic fungi: Candida albicans (CA), Candida parapsilosis (CP), and Cryptococcus neoformans (CN). Minimum inhibitory concentrations (MIC) of the algal extracts were determined by serial dilution method in RPMI 1640 Medium in 96-well plates according to the NCCLS and microbial growth was determined by absorbance at 492nm. A result showing maintenance or reduction of the inoculum was defined as fungistatic, while fungicidal action was no observed growth in the 10 µL fungistatic samples subcultured in Sabouraud Agar. Our results indicate that apolar extracts of Laurencia species possess antifungal properties and encourage continued research to find new drugs for therapy of infectious diseases in these algae.

Resumo em Inglês:

Agaro- and carra-oligosaccharides were produced by partial acid hydrolysis of commercial agarose and kappa-carrageenan. Di- and tetrasaccharides were purified by gel filtration chromatography and characterized by NMR (1D and 2D) spectroscopy and ESIMS. The following oligosaccharides were obtained: agarobiose, agarotetraose, kappa-carrabiose and kappa-carratetraose. Agarobiose and agarotetraose were used as standards to develop a high performance size exclusion chromatography (HPSEC) method which was utilized to study the hydrolysis rate of agarose and oligosaccharide production. Six hours of hydrolysis (0.1 M TFA, 65 ºC) produced mainly di- and tetrasaccharides. The methodology for oligosaccharide production and evaluation developed in the present work shows good potential for the production of bioactive oligosaccharides.

Resumo em Inglês:

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.

Resumo em Inglês:

Decontamination protocols in seaweeds are essential tools for ecophysiological studies in laboratory cultures. These protocols consist of a set of procedures and physical and chemical treatments that must be adjusted for each species. Thus, the effects of explant size and of combinations of physical treatments (brushing and cutting) and chemical treatments (sodium hypochlorite, detergent, seawater, distilled water, germanium dioxide) on the process of obtaining unialgal culture of two pigmentar morphos of Hypnea musciformis were investigated. It was found that thallus segments 50 mm in length, when transported from the field to the laboratory, remained healthier and were less susceptible to epiphytes than those 7 mm in length. The collected material had surfaces contaminated by diatoms, which were weakly attached, as well as surface contamination caused by strongly attached Sahlingia subintegra. The most efficient combination of physical and chemical treatments was explant brushing, cutting and washing with detergent. This combination eliminated the contamination by S. subintegra, but not all of the diatom contamination. The population of the latter was reduced by using physical treatment and by washing with detergent and distilled water and then exterminated by using germanium dioxide (0.003 mg/L). Employing this protocol, unialgal cultures of H. musciformis could be established in approximately eight to ten weeks.

Resumo em Inglês:

The reproductive phenology and thallus length of Gracilaria birdiae were studied over a period of 12 months in a natural bed in Northeastern Brazil. Fertile specimens of G. birdiae were observed during the entire study period. Tetrasporophytes were the most common with an annual mean of 80.1±5.6%, followed by cystocarpic plants (9.3±3.4%), male gametophytes (8.3±3.6%) and infertile plants (2.2±3.4%). Only male gametophytes and infertile plants showed a variation in occurrence frequency during the year (p<0.05). With respect to thallus length, a distinct seasonal variation was observed for all reproductive stages (p<0.05), with the highest values recorded during the rainy season (March to August) and the lowest in the dry season (September to February). The results demonstrate that the size of individuals in this population is significantly affected by the periodic changes in the environment caused by rainfall regimes and hydrodynamism.

Resumo em Inglês:

The coral reefs of Pirangi beach have suffered the impact of anthropic actions, mainly those related to tourism. To evaluate these effects, algal samples were collected at nine stations, distributed along the reef fringe. The macrobenthic community (algae/coral) was identified through photographic methods. A total of thirty species of algae, five species of coral, and one species of mollusk were identified. In areas of intense tourist activity, small algae were predominant, while in areas without human interference, foliose algae were predominant. Cluster analysis of the organisms revealed a pattern in spatial distribution into five zones: (1) a submerged zone with very diverse flora, (2) a zone with a predominance of Caulerpa racemosa, (3) a zone with high coverage of Sargassum vulgare, (4) a trampled zone with bare spaces, small algae and Zoanthus sociatus, and (5) a zone with predominance of Palythoa caribaeroum. The results show that human disturbances of the natural order can result in a different distribution model for benthic organisms in reefs. Moreover, these results allow us to infer that the area studied has undergone changes resulting from human activities and that the differences in biological composition can be used as an important indicator of the health of the Pirangi reef.

Resumo em Inglês:

The absorption efficiency and kinetic parameters (Vmax, Ks and Vmax:Ks) of the seaweed Gracilaria cervicornis for the nutrients NH4+, NO3- and PO4(3-) were evaluated. Absorption efficiency was measured by monitoring nutrient concentrations for 5 h in culture media with initial concentrations of 5, 10, 20 and 30µM. Kinetic parameters were determined by using the Michaelis-Menten formula. Absorption efficiencies for this algae were greater in treatments with lower concentrations, as evidenced by a reduction of 85.3, 97.5 and 81.2% for NH4+, NO3- and PO4(3-), respectively. Kinetic parameters show that G. cervicornis exhibits greater ability to take up high concentrations of NH4+ (Vmax=158.5µM g dw-1 h-1) and low concentrations of PO4(3-) (Ks=5µM and Vmax:Ks=10.3). These results suggest that this algal species has good absorption capacity for the nutrients tested and may be a promising candidate as a bioremediator of eutrophized environments.

Resumo em Inglês:

Micropropagation as a tool for sustainable utilization and conservation of populations of Rhodophyta. Micropropagation, or in vitro clonal propagation, allows the production of a large number of individuals within a short period. These micropropagated clones could be used as seedlings for seaweed cultivation, avoiding collection from natural beds. Consequently, there has been an increasing interest in micropropagation as a tool for preservation of populations of marine red algae on the Brazilian coast and for the sustainable production of raw material for commercial exploration. This paper reviews the literature on tissue culture and micropropagation of red algae published during the three last decades. Based on the literature, we can conclude that the regeneration process is complex and diversified in different species of Rhodophyta and that the success of micropropagation depends on this process. Species belonging to the orders Bangiales and Ceramiales showed low potential for regeneration, while Gigartinales species showed the highest potential for regeneration. Micropropagation of commercially important red algae is fundamental for the conservation of natural populations by providing seedlings for cultivation and for germplasm collections, both for the conservation of genetic diversity and for biotechnological applications.

Resumo em Inglês:

In Brazil, Hypnea musciformis is the main raw material for carrageenan production and the knowledge of nitrogen and phosphorus metabolism in algae is critical for the success of cultivation because these elements can limit seaweed productivity. Thus, the objective of this study was to evaluate the effects of nitrate (zero to 100 μM) and nitrate plus phosphate (zero to 25 μM) availabilities on the growth, the contents of photosynthetic pigments (phycobiliproteins and chlorophyll a) and proteins, and the photosynthesis and respiration of the brown (BR) and light green (LG) strains of H. musciformis. The results revealed metabolic differences between the colour strains of H. musciformis for nitrogen metabolism: upon nitrate addition, the LG strain stored nitrogen mainly as proteins, while the BR strain stored it as proteins and pigments. Moreover, the respiration of the LG strain and the photosynthesis of the BR strain increased with nitrate concentrations, indicating that the BR strain fixed more photosynthetic carbon than the LG strain.

Resumo em Inglês:

We present here the effect of heavy metals and of different light intensities on the biosynthesis of fatty acids and pigments in the macroalga Gracilaria tenuistipitata (var. liui Zhang & Xia). In order to verify the fatty acid content, gas chromatography with flame ionization detection (GC-FID) was employed. Pigments (major carotenoids and chlorophyl-a) were monitored by liquid chromatography with diode array detection (HPLC-DAD). Cultures of G. tenuistipitata were exposed to cadmium (Cd2+, 200 ppb) and copper (Cu2+, 200 ppb), as well as to different light conditions (low light: 100 µmol.photons.m-2.s-1, or high light: 1000 µmol.photons.m-2.s-1). Cd2+ and Cu2+ increased the saturated and monounsaturated fatty acid content [14:0, 16:0, 18:0, 18:1 (n-7) and 18:1 (n-9)] and all major pigments (violaxanthin, antheraxanthin, lutein, zeaxanthin, chlorophyll-a and β-carotene). Both heavy metals decreased the levels of polyunsaturated fatty acids (PUFA) [18:2 (n-6), 18:3 (n-6), 18:5 (n-4), 20:4 (n-6), 20:5 (n-3), 22:6 (n-3)]. G. tenuistipitata cultures were exposed to high light intensity for five days and no statistically significant differences were observed in the content of fatty acids. On the other hand, the levels of pigments rose markedly for chlorophyll-a and all of the carotenoids studied.

Resumo em Inglês:

Gracilaria Greville is a genus of seaweed that is economically explored by the cosmetic, pharmaceutical and food industries. One of the biggest problems associated with growing Gracilaria is the discharge of heavy metals into the marine environment. The absorption of heavy metals was investigated with the macroalga Gracilaria tenuistipitata Zhang et Xia, cultivated in a medium containing copper (Cu) and cadmium (Cd). In biological samples, EC50 concentrations of 1 ppm for cadmium and 0.95 ppm for copper were used. These concentrations were based on seaweed growth curves obtained over a period of six days in previous studies. ICP-AES was used to determine the amount of metal that seaweeds absorbed during this period. G. tenuistipitata was able to bioaccumulate both metals, about 17% of copper and 9% of cadmium. Basal natural levels of Cu were found in control seaweeds and in G. tenuistipitata exposed to Cd. In addition, the repertoire of other important chemical elements, as well as their concentrations, was determined for G. tenuistipitata and two other important seaweeds, G. birdiae Plastino & Oliveira and G. domingensis (Kützing) Sonder ex Dickie, collected in natural environments on the Brazilian shore.

Resumo em Inglês:

In this work we described the cultivation of Chlorella vulgaris in a photobioreactor to algal biomass production. The dried biomass was used as feedstock for biodiesel production, it presented 26% lipids and via sonocatalysis stage of the methodology resulted in 60% of fatty acid methyl esters (FAME). The FAME content was confirmed by Gas Chromatography (GC).