ISOLATION, CHEMICAL CHARACTERIZATION AND BIOLOGICAL ACTIVITIES OF CELL WALL POLYSACCHARIDES OF Laurencia microcladia (RHODOMELACEAE, CERAMIALES)

Polissacarídeos de parede celular da alga vermelha Laurencia microcladia foram isolados por tratamento alcalino (KOH 1M, 10 mg NaBH4, temperatura ambiente), produzindo duas subfrações por neutralização (AcOH, pH=5.2) e precipitação com EtOH, respectivamente A e B. Eletroforese em papel revelou a existência de apenas um polissacarídeo por fração. O espectro FT-IR de ambos polissacarídeos mostraram indícios de COH (OH: 3400-3300 cm-, CO: 1260-1000 cm-) e de CHC (1300 – 1000 cm-), típicos em polímeros de parede celular de algas. Um derivado Nglicosil (1640 – 1560 cm-) e baixo conteúdo ácido (0.34 mol%) são traços estruturais encontrados, ao passo que proteínas não foram encontradas. A atividade antimitótica foi observada em larvas de Lytechinus variegatus (ouriço verde), com valores crônicos de 38.18 mg/mL e 267.99 mg/mL para os polissacarídeos A e B, respectivamente. Não foram observados efeitos antagonistas para bradicinina e acetilcolina para os polissacarídeos em testes in vitro com íleo de porco-da-índia. Resultados preliminares apontaram efeito neurotóxico dessas macromoléculas (5mg/100 mL) além de assimetria do tubo neural em embriões de galinha.Cell wall polysaccharides of the red algae Laurencia microcladia were isolated by alkaline treatment (KOH 1M, 10 mg NaBH4, room temperature), yielding two sub-fractions by neutralization (AcOH, pH=5.2) and EtOH precipitation, respectively A and B. Paper electrophoresis revealed the existence of only one polysaccharide in each fraction. FT-IR spectra of both polysaccharides showed signals for COH (OH: 3400-3300 cm-, CO: 1260-1000 cm-) and CHC (1300 – 1000 cm-) typical of cell wall algal polymers. An N-glyco derivative (1640 – 1560 cm-) and a low acidic content (0.34 mol %) were structural features found, while proteins were not detected. Antimitotic activity was observed on Lytechinus variegatus (green bur) larvae, with chronic values of 38.18 mg/mL and 267.99 mg/mL for polysaccharides A and B, respectively. No bradykinin or acetylcholine antagonistic effect was observed when polysaccharides were assayed in vitro in guinea-pig ileum. Preliminary results pointed to neurotoxic effect of these macromolecules (5mg/100 mL) since asymmetry of the neural tube in chick embryo was also found

A transcriptomic analysis of gene expression in the venom gland of the snake Bothrops alternatus (urutu)

<p>Abstract</p> <p>Background</p> <p>The genus <it>Bothrops </it>is widespread throughout Central and South America and is the principal cause of snakebite in these regions. Transcriptomic and proteomic studies have examined the venom composition of several species in this genus, but many others remain to be studied. In this work, we used a transcriptomic approach to examine the venom gland genes of <it>Bothrops alternatus</it>, a clinically important species found in southeastern and southern Brazil, Uruguay, northern Argentina and eastern Paraguay.</p> <p>Results</p> <p>A cDNA library of 5,350 expressed sequence tags (ESTs) was produced and assembled into 838 contigs and 4512 singletons. BLAST searches of relevant databases showed 30% hits and 70% no-hits, with toxin-related transcripts accounting for 23% and 78% of the total transcripts and hits, respectively. Gene ontology analysis identified non-toxin genes related to general metabolism, transcription and translation, processing and sorting, (polypeptide) degradation, structural functions and cell regulation. The major groups of toxin transcripts identified were metalloproteinases (81%), bradykinin-potentiating peptides/C-type natriuretic peptides (8.8%), phospholipases A₂(5.6%), serine proteinases (1.9%) and C-type lectins (1.5%). Metalloproteinases were almost exclusively type PIII proteins, with few type PII and no type PI proteins. Phospholipases A₂were essentially acidic; no basic PLA₂were detected. Minor toxin transcripts were related to L-amino acid oxidase, cysteine-rich secretory proteins, dipeptidylpeptidase IV, hyaluronidase, three-finger toxins and ohanin. Two non-toxic proteins, thioredoxin and double-specificity phosphatase Dusp6, showed high sequence identity to similar proteins from other snakes. In addition to the above features, single-nucleotide polymorphisms, microsatellites, transposable elements and inverted repeats that could contribute to toxin diversity were observed.</p> <p>Conclusions</p> <p><it>Bothrops alternatus </it>venom gland contains the major toxin classes described for other <it>Bothrops </it>venoms based on trancriptomic and proteomic studies. The predominance of type PIII metalloproteinases agrees with the well-known hemorrhagic activity of this venom, whereas the lower content of serine proteases and C-type lectins could contribute to less marked coagulopathy following envenoming by this species. The lack of basic PLA₂agrees with the lower myotoxicity of this venom compared to other <it>Bothrops </it>species with these toxins. Together, these results contribute to our understanding of the physiopathology of envenoming by this species.</p

TESTES PRELIMINARES DE CRESCIMENTO COM UMA CEPA DA MICROALGA PRODUTORA DE ASTAXANTINA Haematococcus pluvialis (CHLOROPHYCEAE,VOLVOCALES)

This paper describes a preliminary growth experiment with a strain of the astaxanthin producer Haematococcus pluvialis (Chlorophyceae, Volvocales). Cultures with 4 different cell compositions in terms of density and coloration of aplanospores and macrozooids, were kept under 20°C ± 2°C, 70µE.m-2.s-1, 12h light : 12h dark and appropriate culture media for about 900h. 2ml samples were collected periodically, in order to determine cells density. Results indicated a similar growth pattern to all cultures, where green macrozooids were dominant in the first days being numerically got over by aplanospores after aproximatelly 300h. Maximal number of aplanospores were attained at 800h. The experiment showed that the strain is viable and can be used to physiological studies about optimal growth conditions and astaxanthin production.Este trabalho descreve um experimento preliminar de crescimento com uma cepa da microalga produtora de astaxantina Haematococcus pluvialis (Chlorophyceae, Volvocales). Cultivos com 4 composições diferentes de células em termos de proporção e coloração de aplanósporos e macrozoóides, foram submetidos à 20°C ± 2°C, 70µE.m-2.s-1, fotoperíodo de 12 horas de luz : 12 horas de escuro e meio de cultura adequado por cerca de 900 horas. Alíquotas de 2 ml eram retiradas periodicamente ao longo do experimento para a determinação da densidade de células e construção das curvas de crescimento. Os resultados indicaram um padrão de crescimento similar para todos os frascos de cultivo, onde os macrozoóides predominavam nos primeiros dias sendo substituídos gradualmente por aplanósporos, que tornaram-se dominantes em torno de 300 horas. A densidade máxima de aplanósporos foi verificada em torno das 800 horas de experimento. O experimento como um todo, mostrou que a cepa testada é viável, podendo ser utilizada para experimentos específicos de determinação das condições ótimas de crescimento e produção de astaxantina

Variability of filtration and food assimilation rates, respiratory activity and multixenobiotic resistance (MXR) mechanism in the mussel Perna perna under lead influence

The economic importance that myticulture is conquering in Santa Catarina State (South of Brazil) explains the crescent search for new coastal sites for farming. Physiological and biochemical studies of the mussel Perna perna are important to the establishment of methodologies for program assessment and environmental monitoring, allowing to infer about site quality and possible influences of xenobiotic agents on coastal areas. In order to evaluate effects caused by lead poisoning (1.21 mumol.L-1), the mussels were maintained at constant temperature (25ºC) and fed with Chaetoceros gracilis for 15 days. The control group was acclimatized in sea water 30?. At the end of this period time, physiological measurements were carried out along with statistic analysis for filtration rates, lead assimilation and overall respiratory activity. The mechanism of multixenobiotic resistance (MXR) was particularly evaluated in standardized gill fragments using rhodamine B accumulation and its quantification under fluorescence optical microscopy. Regarding the control group, results had shown that the mussels maintenance in a lead-poisoned environment caused higher filtration rates (1.04 and 2.3 and L.h-1.g-1; p < 0.05) and lower assimilation rates (71.96% and 54.1%, respectively). Also it was confirmed a lesser rhodamine B accumulation in the assays under influence of lead, suggesting that this metal induces the MXR mechanism expression in mussel P. perna. These results indicate that such physiological and biochemical alterations in the mussels can modify the energy fluxes of its metabolism, resulting in possible problems on the coastal systems used as cultivating sites

Variability of filtration and food assimilation rates, respiratory activity and multixenobiotic resistance (MXR) mechanism in the mussel Perna perna under lead influence

The economic importance that myticulture is conquering in Santa Catarina State (South of Brazil) explains the crescent search for new coastal sites for farming. Physiological and biochemical studies of the mussel Perna perna are important to the establishment of methodologies for program assessment and environmental monitoring, allowing to infer about site quality and possible influences of xenobiotic agents on coastal areas. In order to evaluate effects caused by lead poisoning (1.21 mumol.L-1), the mussels were maintained at constant temperature (25ºC) and fed with Chaetoceros gracilis for 15 days. The control group was acclimatized in sea water 30‰. At the end of this period time, physiological measurements were carried out along with statistic analysis for filtration rates, lead assimilation and overall respiratory activity. The mechanism of multixenobiotic resistance (MXR) was particularly evaluated in standardized gill fragments using rhodamine B accumulation and its quantification under fluorescence optical microscopy. Regarding the control group, results had shown that the mussels maintenance in a lead-poisoned environment caused higher filtration rates (1.04 and 2.3 and L.h-1.g-1; p < 0.05) and lower assimilation rates (71.96% and 54.1%, respectively). Also it was confirmed a lesser rhodamine B accumulation in the assays under influence of lead, suggesting that this metal induces the MXR mechanism expression in mussel P. perna. These results indicate that such physiological and biochemical alterations in the mussels can modify the energy fluxes of its metabolism, resulting in possible problems on the coastal systems used as cultivating sites

Variability of filtration and food assimilation rates, respiratory activity and multixenobiotic resistance (MXR) mechanism in the mussel Perna perna under lead influence

The economic importance that myticulture is conquering in Santa Catarina State (South of Brazil) explains the crescent search for new coastal sites for farming. Physiological and biochemical studies of the mussel Perna perna are important to the establishment of methodologies for program assessment and environmental monitoring, allowing to infer about site quality and possible influences of xenobiotic agents on coastal areas. In order to evaluate effects caused by lead poisoning (1.21 mumol.L-1), the mussels were maintained at constant temperature (25ºC) and fed with Chaetoceros gracilis for 15 days. The control group was acclimatized in sea water 30‰. At the end of this period time, physiological measurements were carried out along with statistic analysis for filtration rates, lead assimilation and overall respiratory activity. The mechanism of multixenobiotic resistance (MXR) was particularly evaluated in standardized gill fragments using rhodamine B accumulation and its quantification under fluorescence optical microscopy. Regarding the control group, results had shown that the mussels maintenance in a lead-poisoned environment caused higher filtration rates (1.04 and 2.3 and L.h-1.g-1; p < 0.05) and lower assimilation rates (71.96% and 54.1%, respectively). Also it was confirmed a lesser rhodamine B accumulation in the assays under influence of lead, suggesting that this metal induces the MXR mechanism expression in mussel P. perna. These results indicate that such physiological and biochemical alterations in the mussels can modify the energy fluxes of its metabolism, resulting in possible problems on the coastal systems used as cultivating sites