Co-stressors chilling and high light increase photooxidative stress in diuron-treated red alga Kappaphycus alvarezii but with lower involvement of H2O2

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Daily dynamics of photosynthesis of the freshwater red alga Sirodotia delicatula (Batrachospermales, Rhodophyta)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Characterization of a novel freshwater gigartinalean red alga from Belize, with a description of Sterrocladia belizeana sp nov (Rhodophyta)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influência da distribuição granulométrica na estabilidade dimensional de placas cerâmicas de base vermelha

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Produção da tilápia vermelha da Flórida em tanques-rede

A produção de peixes em tanques-rede no Brasil tem aumentado nas últimas décadas. O baixo investimento inicial e o potencial hídrico representado pela enorme quantidade de água represada em nosso País têm atraído o interesse de empresários para essa atividade. O objetivo desse trabalho foi gerar informações sobre o efeito da densidade de estocagem no crescimento e produtividade da tilápia vermelha da Flórida criadas em tanques-rede. Foram instalados doze tanques-rede de 5 m3, numa represa de 1 ha, e estocados com 25, 50, 75 e 100 tilápias vermelhas da Flórida revertidas por m3. Os peixes foram alimentados com rações extrusadas comerciais contendo 32 e 28% PB por 253 dias. As temperaturas máxima, mínima e média da água foram 32,2, 16,0 e 23,9 C, respectivamente. Também foram monitorados a condutividade (58 mS/cm2), alcalinidade total (28 mg/L), amônia não ionizada (0,26 mg/L), nitrito (0,02 mg/L), oxigênio dissolvido (4,1 mg/L) e transparência da água (37 cm). Foram determinados o peso médio final (279,54g), comprimento padrão médio final (18,72cm), fator de condição (4,12), conversão alimentar aparente (3,15), taxa de sobrevivência (96,9%), ganho de peso diário (0,92g), taxa de crescimento específico (0,70%) e coeficientes de variação do peso (0,357%), do comprimento padrão (0,136%) e do fator de condição (0,136%). Não foram observadas diferenças significativas (P>0,05) entre as densidades de estocagem testadas nesses parâmetros. A densidade de estocagem de 100 peixes/m3 proporcionou a maior biomassa por m3 (P<0,001).

Uso da alga Lithothamnium calcareum como fonte alternativa de cálcio nas rações de frangos de corte

Objetivou-se, com este trabalho, avaliar o uso da alga Lithothamnium calcareum (Pallas) Areschoug nas rações para frangos de corte de 1 a 21 e 21 a 42 dias de idade, em substituição à fonte de cálcio tradicional (calcário calcítico). Para isso, foram utilizados 300 pintos machos, da linhagem Cobb®, que receberam rações contendo o calcário calcítico e a alga Lithothamnium calcareum (colhida de inteira e na forma de areia biodentrítica) como fontes de cálcio. O delineamento experimental utilizado foi o inteiramente casualizado, com três tratamentos e cinco repetições de 20 aves cada. As variáveis analisadas foram: ganho de peso (g/ave), consumo de ração (g/ave) e conversão alimentar (g/g). No final do experimento foram avaliados os parâmetros ósseos: peso da tíbia (g), comprimento da tíbia (mm), diâmetro da tíbia (mm) e teor de cinzas na tíbia (%). Na fase inicial (1 a 21 dias) houve efeito (P<0,05) entre os tratamentos para o ganho de peso e conversão alimentar, sendo que o tratamento controle apresentou melhores resultados. Para a fase de crescimento (21 a 42 dias) e período total (1 a 42 dias) não houve efeito entre os tratamentos estudados. A utilização da alga Lithothamnium calcareum (independente da forma de colheita) em substituição à fonte de cálcio tradicional (calcário calcítico) pode ser recomendada para as rações de frangos de corte, sem prejudicar o desempenho zootécnico. Porém, deve-se levar em consideração a viabilidade econômica do uso dessa fonte alternativa nas rações.

The use of silica-immobilized brown alga (Pilayella littoralis) for metal preconcentration and determination by inductively coupled plasma optical emission spectrometry

The brown alga Pilayella littoralis was used as a new biosorbent in an on-line metal preconcentration procedure in a flow-injection system. Al, Co, Cu and Fe were determined in lake water samples by inductively coupled plasma optical emission spectrometry (ICP-OES) after preconcentration in a silica-immobilized alga column. Like other algae, P. littoralis exhibited strong affinity for these metals proving to be an effective accumulation medium. Metals were bound at pH 5.5 and were displaced at pH < 2 with diluted HCl. The enrichment factors for Cu-II, Fe-III, Al-III and Co-II were 13, 7, 16 and 11, respectively. Metal sorption efficiency ranged from 86 to 90%. The method accuracy was assessed by using drinking water certified reference material and graphite furnace atomic absorption spectrometry (GFAAS) as a comparison technique. The column procedure allowed a less time consuming, easy regeneration of the biomaterial and rigidity of the alga provided by its immobilization on silica gel. (C) 2003 Elsevier B.V. All rights reserved.

Influência do alecrim (Rosmarinus officinallis L.) na atividade de água e oxidação lipídica de peixes de uma espécie de tilápia (Oreochromis ssp-var. vermelha Flórida) submetidos à salga

Salting have been a very utilized fish conservation method, however only in the last years the basic mechanism involved in salting fish has been understood. The objectives of this study were determine the addition in brine salt of rosemary leaves, rosemary extracts and tocopherol, and your action in the followed parameters: water activity (Aw), moisture, ash, salt content and TBARS. The results showed that the addition of antioxidants was difficulted the salt absorption, however didn't have differences between rosemary or tocopherol use. In the salting time of 3 hours the values of Aw and salt levels, was respectively: 0.77±0.01 and 14.42±1.69. for control treatment; 0.85±0.02 and 9.09±1.39for rosemary filtrate; 0.78±0.03 and 10.63±0.69 rosemary without filtrating and 0.85±0.02 and 11.96±1.78 tocopherol, showed that didn't grow indigenous bacterias. Lipid oxidation was evaluated by TBARS and the results showed the oxidative effect of salt and the pro oxidant effects of alls antioxidants used in brine salting.

Reproductive ecology of the freshwater red alga Batrachospermum delicatulum (Batrachospermales, Rhodophyta) in three tropical streams

Batrachospermum delicatulum specimens from three stream segments were analyzed from a tropical region in south-eastern Brazil (20°18′- 20°49′S, 49°13′-49°46′W). Physical and chemical parameters and the spatial placement of thalli were investigated along with the reproductive characteristics of the gametophytic phase. Sequence data of the cox 2-3 spacer region was also utilized to evaluate genetic variation in individuals within and among stream segments. Gametophyte occurred under relatively diverse environmental conditions, whereas thalli abundance was weakly or not correlated to environmental variables within the stream segments. All specimens examined were dioecious. The ratio of male/female plants was relatively low (0.5 to 1.3) and male plants tended to occur as clumps (two or three plants together). High reproductive success was observed, as indicated by the occurrence of 100% fertilized (carposporophytic) female plants. This is similar to previous reports for this and other dioecious species, which is remarkable considering the relatively low proportion of male/female plants. Results support the two hypotheses to explain the high reproductive success in dioecious species. The occurrence of male plants in clumps was evidence for a strict spatial relationship (i.e. male plants located in upstream position of female plants in order to release spermatia, which would be carried by eddies through female plants). In contrast, the occurrence of male and female plants adjacent to each other allowed outcrossing among neighboring plants with intermingled male and female branches, which seemed more applicable to some situations (low turbulence habitats). The cox 2-3 spacer region from the 18 individuals sequenced was 376 bp and the DNA sequence was identical with no base pair substitutions. Likewise, a previous study of another Batrachospermum species showed that the same haplotypes were present in all stream segments from the same drainage basin, even though the stream segments were a considerable distance apart. Short distance dispersal either by small birds or waterway connectivity might explain these findings.

Kinetic study of the plastoquinone pool availability correlated with H2O2 release in seawater and antioxidant responses in the red alga Kappaphycus alvarezii exposed to single or combined high light, chilling and chemical stresses

Under biotic/abiotic stresses, the red alga Kappaphycus alvarezii reportedly releases massive amounts of H2O2 into the surrounding seawater. As an essential redox signal, the role of chloroplast-originated H2O2 in the orchestration of overall antioxidant responses in algal species has thus been questioned. This work purported to study the kinetic decay profiles of the redox-sensitive plastoquinone pool correlated to H2O2 release in seawater, parameters of oxidative lesions and antioxidant enzyme activities in the red alga Kappaphycus alvarezii under the single or combined effects of high light, low temperature, and sub-lethal doses of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), which are inhibitors of the thylakoid electron transport system. Within 24 h, high light and chilling stresses distinctly affected the availability of the PQ pool for photosynthesis, following Gaussian and exponential kinetic profiles, respectively, whereas combined stimuli were mostly reflected in exponential decays. No significant correlation was found in a comparison of the PQ pool levels after 24 h with either catalase (CAT) or ascorbate peroxidase (APX) activities, although the H2O2 concentration in seawater (R = 0.673), total superoxide dismutase activity (R = 0.689), and particularly indexes of protein (R = 0.869) and lipid oxidation (R = 0.864), were moderately correlated. These data suggest that the release of H2O2 from plastids into seawater possibly impaired efficient and immediate responses of pivotal H2O2-scavenging activities of CAT and APX in the red alga K. alvarezii, culminating in short-term exacerbated levels of protein and lipid oxidation. These facts provided a molecular basis for the recognized limited resistance of the red alga K. alvarezii under unfavorable conditions, especially under chilling stress. © 2006 Elsevier B.V. All rights reserved.

Modulation of the pharmacological effects of enzymatically-active PLA 2 by BTL-2, an isolectin isolated from the Bryothamnion triquetrum red alga

Background. An interaction between lectins from marine algae and PLA 2 from rattlesnake was suggested some years ago. We, herein, studied the effects elicited by a small isolectin (BTL-2), isolated from Bryothamnion triquetrum, on the pharmacological and biological activities of a PLA 2 isolated from rattlesnake venom (Crotalus durissus cascavella), to better understand the enzymatic and pharmacological mechanisms of the PLA 2 and its complex. Results. This PLA2 consisted of 122 amino acids (approximate molecular mass of 14 kDa), its pI was estimated to be 8.3, and its amino acid sequence shared a high degree of similarity with that of other neurotoxic and enzymatically-active PLA2s. BTL-2 had a molecular mass estimated in approximately 9 kDa and was characterized as a basic protein. In addition, BTL-2 did not exhibit any enzymatic activity. The PLA2 and BTL-2 formed a stable heterodimer with a molecular mass of approximately 24-26 kDa, estimated by molecular exclusion HPLC. In the presence of BTL-2, we observed a significant increase in PLA2 activity, 23% higher than that of PLA2 alone. BTL-2 demonstrated an inhibition of 98% in the growth of the Gram-positive bacterial strain, Clavibacter michiganensis michiganensis (Cmm), but only 9.8% inhibition of the Gram-negative bacterial strain, Xanthomonas axonopodis pv passiflorae (Xap). PLA2 decreased bacterial growth by 27.3% and 98.5% for Xap and Cmm, respectively, while incubating these two proteins with PLA2-BTL-2 inhibited their growths by 36.2% for Xap and 98.5% for Cmm. PLA2 significantly induced platelet aggregation in washed platelets, whereas BTL-2 did not induce significant platelet aggregation in any assay. However, BTL-2 significantly inhibited platelet aggregation induced by PLA2. In addition, PLA 2 exhibited strong oedematogenic activity, which was decreased in the presence of BTL-2. BTL-2 alone did not induce oedema and did not decrease or abolish the oedema induced by the 48/80 compound. Conclusion. The unexpected results observed for the PLA2-BTL-2 complex strongly suggest that the pharmacological activity of this PLA2 is not solely dependent on the presence of enzymatic activity, and that other pharmacological regions may also be involved. In addition, we describe for the first time an interaction between two different molecules, which form a stable complex with significant changes in their original biological action. This opens new possibilities for understanding the function and action of crude venom, an extremely complex mixture of different molecules. © 2008 Oliveira et al; licensee BioMed Central Ltd.

Adsorção do corante reativo azul 19 em solução aquosa por lama vermelha tratada quimicamente com peró:xido de hidrogênio

Adsorption of Reactive Blue 19 dye onto activated red mud was investigated. Red mud was treated with hydrogen peroxide (LVQ) and heated at both 400 °C (LVQ400) and 500 °C (LVQ500). These samples were characterized by pH, specific surface area, point of zero charge and mineralogical composition. Adsorption was found to be significantly dependent on solution pH, with acidic conditions proving to be the most favorable. The adsorption followed pseudo-second-order kinetics. The Langmuir isotherm was the most appropriate to describe the phenomenon of dye removal using LVQ, LVQ400 and LVQ500, with maximum adsorption capacity of 384.62, 357.14 and 454.54 mg g-1, respectively.

A new mid-Cretaceous Neomeris (dasycladacean alga) from the Potiguar Basin, Brazil

Neomeris (Lamouroux, 1816) is an extant taxon, the origin of which can be tracked back into Early Cretaceous times. The introduction of a new mid-Cretaceous species from Brazil, i.e., Neomeris srivastavai n. sp., offers the opportunity to review the subdivision of the genus into three subgenera, to complete the catalogue of the fossil calcareous algae of Brazil, and to point out the huge stratigraphic gap and lack of documentation between the first occurrence of the dasycladacean model of reproduction, i.e., choristospory, and the oldest record so far known of an undescribed fossil Neomeris (from Portugal). © Springer-Verlag Berlin Heidelberg 2012.

Avaliação das respostas fotossintéticas de macroalgas lóticas sobre diferentes composições espectrais da radiação incidente

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)