Flora de comunidades de macroalgas lóticas de fragmentos florestais remanescentes da região noroeste do Estado de São Paulo, Brasil

Foram amostrados 17 riachos, em 12 fragmentos durante a estação seca (junho a agosto de 2007 e de 2008). Foram identificadas 16 espécies de macroalgas, pertencentes a 14 gêneros. Cyanophyta e Chlorophyta foram os grupos mais representativos (44 e 38%, respectivamente), seguidos por Rhodophyta (12%) e Heterokontophyta (6%). O número global de espécies foi baixo, fato atribuído à predominância de substrato areno-argiloso (65%) e de trechos sombreados (53%). A maioria das espécies (69%) ocorreu exclusivamente em um único riacho, padrão frequentemente observado para macroalgas lóticas. Vaucheria pseudogeminata foi reportada pela primeira vez para o Brasil e Trichocoleus sociatus para a região noroeste do Estado de São Paulo. Comparando a flora de macroalgas encontrada com aquelas de outras regiões/biomas do Estado de São Paulo, notou-se maior semelhança com Floresta Tropical (56% espécies em comum), conforme esperado, por ser o bioma mais próximo e composto também por Floresta Estacional Semidecidual.

Phytoplankton assemblages in lateral lagoons of a large tropical reservoir

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Light-related photosynthetic characteristics of lotic macroalgae

Photosynthetic characteristics in response to irradiance were analysed in 42 populations of 33 macroalgal species by two distinct techniques (chlorophyll fluorescence and oxygen evolution). Photosynthesis-irradiance (PI) curves based on the two techniques indicated adaptations to low irradiance reflected by low saturation values, high to moderate values of photosynthetic efficiency (alpha) and photoinhibition (beta), for Bacillariophyta and Rhodophyta, which suggests they are typically shade-adapted algae. In contrast, most species of Chlorophyta were reported as sun adapted algae, characterized by high values of I-k and low of alpha, and lack of or low photoinhibition. Cyanophyta and Xanthophyta were intermediate groups in terms of light adaptations. Photoinhibition was observed in variable degrees in all algal groups, under field and laboratory conditions, which confirms that it is not artificially induced by experimental conditions, but is rather a common and natural phenomenon of the lotic macroalgae. Low values of compensation irradiance (I-c) were found, which indicate that these algae can keep an autotrophic metabolism even under very low irradiances. High ratios (>2) of photosynthesis/respiration were found in most algae, which indicates a considerable net gain. These two physiological characteristics suggest that macroalgae may be important primary producers in lotic ecosystems. Saturation parameters (I-k and I-s) occurred in a relatively narrow range of irradiances (100-400 mumol photons m(-2) s(-1)), with some exceptions (higher in some filamentous green algae or lower in red algae). These parameters were way below the irradiances measured at collecting sites for most algae, which means that most of the available light energy was not photochemically converted via photosynthesis. Acclimation to ambient PAR was observed, as revealed by lower values of I-k and I-c and higher values of alpha and quantum yield in algae from shaded streams, and vice versa. Forms living within the boundary layer (crusts) showed responses of shade-adapted species and had the highest values of P-max, alpha and quantum yield, whereas the opposite trend was observed in gelatinous forms (colonies and. laments). These results suggests adaptation to the light regime rather than functional attributes related to the growth form.

Uso de macroalgas para avaliação da Poluição orgânica no Rio Preto, noroeste do estado de São Paulo.

The Preto River, located in the northwest of São Paulo State, receives a total wastewater load of 15.150 kg DBO day-1, from which 13.685 kg DBO day-1 (90.5%) corresponds to domestic sewage, and the city of São José do Rio Preto contributes with 12.400 kg DBO day-1 (90% of domestic sewage). During the period from August 1990 through January 1991, monthly sampling was carried out to evaluate the use of macroalgae as bioindicator of organic pollution. Five sampling sites were established along the main river and the following variables were analised: temperature, conductance, turbidity, dissolved oxygen, BOD, COD, total and fecal coliforms, and composition and abundance of macroalgal communities. Data were submitted to analysis of variance, correlation coefficient, cluster analysis (four different approaches) and converted to biological indices (species deficit, relative pollution, saprobity, diversity and uniformity indices). A wide range in water quality was found (particularly for conductance, oxygen, BOD and COD) among the sampling sites, which were classified into three groups (polluted, moderately polluted and unpolluted/weakly polluted). As regards the occurrence and abundance of macroalgae the Rhodophyta were found only in unpolluted or weakly polluted sites, whereas Cyanophyta occurred mostly under high pollution load; the Chlorophyta species were observed under a wide range of conditions. Among the biological indices, saprobity was the most sensitive and correlated to all water variables and the other indices. Cluster analyses showed that the composition of macroalgal communities was consistent with the levels of organic pollution in the Preto River.

The effects of Chlorella vulgaris in the protection of mice infected with Listeria monocytogenes. Role of natural killer cells

In this work we have demonstrated the effects of oral administration of Chlorella vulgaris (CV) on Natural Killer cells (NK) activity of mice infected with a sublethal dose of viable Listeria monocytogenes. The treatment with C. vulgaris produced a significant increase on NK cells activity in normal (non-infected) animals compared to the animals that received only vehicle (water) (p < 0.0001). Similarly, the infection alone produced a significant increase on NK cells activity, which was observed at 48 and 72 hours after the inoculation of L. monocytogenes. Moreover, when CV was administered in infected animals, there was an additional increase in NK cells activity which was significantly higher than that found in the infected groups (p < 0.0001) CV treatment (50 and 500mg/Kg) of mice infected with a dose of 3x105 bacteria/animal, which was lethal for all the non- treated controls, produced a dose-response protection which led to a 20% and 55% survival, respectively (p < 0.0001).

Photosynthetic responses to temperature in tropical lotic macroalgae

A comparative analysis of the photosynthetic responses to temperature (10-30°C) was carried out under short-term laboratory conditions by chlorophyll fluorescence and oxygen (O2) evolution. Ten lotic macroalgal species from southeastern Brazil (20°11-20°48′S, 49°18-49°41′W) were tested, including Bacillariophyta, Chlorophyta, Cyanophyta, Rhodophyta and Xanthophyta. Temperature had significant effects on electron transport rate (ETR) only for three species (Terpsinoe musica, Bacillariophyta; Cladophora glomerata, Chlorophyta; and C. coeruleus, Rhodophyta), with highest values at 25-30°C, whereas the remaining species had no significant responses. It also had similar effects on non-photochemical quenching and ETR. Differences in net photosynthesis/dark respiration ratios at distinct temperatures were found, with an increasing trend of respiration with higher temperatures. This implies in a decreasing balance between net primary production and temperature, representing more critical conditions toward higher temperatures for most species. In contrast, high net photosynthesis and photosynthesis/dark respiration ratios at high and wide ranges of temperature were found in three species of green algae, suggesting that these algae can be important primary producers in lotic ecosystems, particularly in tropical regions. Optimal photosynthetic rates were observed under similar environmental temperatures for five species (two rhodophytes, two chlorophytes and one diatom) considering both techniques, suggesting acclimation to their respective ambient temperatures. C. coeruleus was the only species with peaks of ETR and O 2 evolution under similar field-measured temperatures. All species kept values of ETR and net photosynthesis close to the optimum under a broad range of temperatures. Increased non-photochemical quenching, as a measure of thermal dissipation of excess energy, toward higher temperatures was observed in some species, as well as positive correlation of non-photochemical quenching with ETR, and were interpreted as two mechanisms of adaptation of the photosynthetic apparatus to temperature changes. Different optimal temperatures were found for individual species by each technique, generally under lower temperatures by O2 evolution, indicating dependence on distinct factors: increases in temperature generally induced higher ETR due to increased enzymatic activity, whereas increments of enzymatic activity were compensated by increased respiration and photorespiration leading to decreases in net photosynthesis.

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)

Macroalgas lóticas do Parque Nacional Chapada dos Veadeiros e arredores (GO): levantamento florístico e distribuição ecológica das comunidades

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

Características fotossintéticas de produtores primários de ambientes lóticos

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Flora e distribuição ecológica de comunidades de macroalgas lóticas de fragmentos florestais da região noroeste do estado de São Paulo

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Avaliação da qualidade da água do rio Poti na cidade de Teresina, Piauí

Pós-graduação em Geografia - IGCE

Análise comparativa da dieta, seletividade alimentar e estrutura da ictiofauna, juvenis e espécies de pequeno porte, em lagoas marginais do reservatório de Rosana (Rio Paranapanema, SP/PR)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estrutura das comunidades de macroalgas da bacia de drenagem do rio Cascavel, Estado do Paraná, Brasil

The drainage basin of Cascavel River is almost entirely within the urban perimeter of Guarapuava, Paraná State, Brazil. Seven stream segments were sampled in two seasons (summer and winter). We found 12 taxa of macroalgae with a dominance of Chlorophyta (seven taxa) followed by Cyanophyta (three taxa), Heterokontophyta and Rhodophyta (one taxon each). Richness, diversity, and evenness were higher during the winter while the abundance and dominance were higher in the summer. Among the microenvironmental characteristics, the current velocity was the only one that differed significantly between the periods. The regression analysis revealed that the richness of the substrate was responsible for the variation in richness, diversity, evenness, and dominance during the summer period. During the winter the current velocity was responsible for the variation of species diversity. A cluster analysis of macroalgal communities did not group points in the same temporal period. The Canonical Correspondence Analysis (CCA) showed that the segments were close to each other because of the occurrence of one or a few species in common. The patterns of spatial and temporal distribution of stream macroalgae seem to be strongly influenced by microhabitat characteristics at different scales.However, they aresupported by regional variables.

The roles of environmental conditions and spatial factors in controlling stream macroalgal communities

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

Riqueza, abundância e sazonalidade de comunidades de macroalgas em diferentes escalas espaciais em riachos da região centr-sul do estado do Paraná

Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq)