RESUMO
The Phytoplankton community and the abiotic factors of the Cruzeta reservoir were studied at three depths, surface, middle (2 m) and bottom, from September, 2004 to June, 2005, in order to characterize the environment and assess the possible factors that influence the compositional change of phytoplankton. Ninety species belonging to 6 classes (Chlorophyceae, Bacillariophyceae, Cyanophyceae, Dinophyceae, Chrysophyceae and Euglenophyceae) were identified with 66 and 80 taxonomic units in the dry and rainy season. The most representative class in terms of species richness was Chlorophyceae and dominated by Scendesmus quadricauda, Oocystis sp. and Chlorella sp. The group cyanobacteria were represented by 18 species of diverse morphological characteristics and the dominance of Cylindrospermopsis raciborskii in September 2004. The other major group, Bacillariophyceae is represented by 21 species with the predominance of Aulacoseira granulata in mid-column and bottom waters. The other dominant species was Phacus acuminatus of Euglenophyceae. The species diversity and evenness indices were high, moderate and low in relation to the three hydroperiod registered during the 2004-2005 annual cycle. The reservoir exhibits high electrical conductivity (290-550 microS x cm-1), alkaline pH (7.3-9.4), mean temperature of 28 degrees C, varying concentrations of dissolved oxygen (3.29-7.6 mg x L-l) and the greatest concentration of nutrients at the bottom (orthophosphate, 0.22-0.62 mg x L-1) with the general tendency of oligo-mesotrophic status during sampling periods. The chlorophyll a fluctuated to a minimum of 1.34 microg x L-l at the bottom in April, 2005 and a maximum of 14.3 microg x L-l in mid-column water in September, 2004. The reservoir is characteristically an oligo-mesotrophic environment.
Assuntos
Clorofila/análise , Monitoramento Ambiental , Água Doce/análise , Fitoplâncton/classificação , Animais , Biomassa , Brasil , Físico-Química , Clorofila A , Densidade Demográfica , Estações do AnoRESUMO
The Phytoplankton community and the abiotic factors of the Cruzeta reservoir were studied at three depths, surface, middle (2 m) and bottom, from September, 2004 to June, 2005, in order to characterize the environment and assess the possible factors that influence the compositional change of phytoplankton. Ninety species belonging to 6 classes (Chlorophyceae, Bacillariophyceae, Cyanophyceae, Dinophyceae, Chrysophyceae and Euglenophyceae) were identified with 66 and 80 taxonomic units in the dry and rainy season. The most representative class in terms of species richness was Chlorophyceae and dominated by Scendesmus quadricauda, Oocystis sp. and Chlorella sp. The group cyanobacteria were represented by 18 species of diverse morphological characteristics and the dominance of Cylindrospermopsis raciborskii in September 2004. The other major group, Bacillariophyceae is represented by 21 species with the predominance of Aulacoseira granulata in mid-column and bottom waters. The other dominant species was Phacus acuminatus of Euglenophyceae. The species diversity and evenness indices were high, moderate and low in relation to the three hydroperiod registered during the 2004-2005 annual cycle. The reservoir exhibits high electrical conductivity (290-550 µS.cm-1), alkaline pH (7.3-9.4), mean temperature of 28 °C, varying concentrations of dissolved oxygen (3.29-7.6 mg.L-l) and the greatest concentration of nutrients at the bottom (orthophosphate, 0.22-0.62 mg.L-1) with the general tendency of oligo-mesotrophic status during sampling periods. The chlorophyll a fluctuated to a minimum of 1.34 µg.L-l at the bottom in April, 2005 and a maximum of 14.3 µg.L-l in mid-column water in September, 2004. The reservoir is characteristically an oligo-mesotrophic environment.
A comunidade fitoplanctônica e os fatores abióticos do açude Cruzeta foram estudados em três profundidades, superfície, meio (2 m) e fundo, de setembro, 2004 a junho, 2005, com o intuito de caracterizar e avaliar os possíveis fatores que influenciam as mudanças composicionais do fitoplâncton. Noventa espécies pertencentes a 06 classes (Chlorophyceae, Bacillariophyceae, Cyanophyceae, Dinophyceae, Chrysophyceae e Euglenophyceae) foram identificadas com 66 e 80 unidades taxonômicas nas estações de seca e de chuvas. A riqueza de espécies foi classe Chlorophyceae, com dominância de Scenedesmus quadriculata, Oocystis sp. e Chlorella sp. O grupo das Cyanophyceae foi representado por 18 espécies de características diversas com dominância de Cylindrospermopsis raciborskii em Setembro 2004. Em seguida, foi encontrado o grupo das Bacillariophyceae, representado por 21 espécies com a predominância de Aulacoseira granulata no fundo d'água. Outra espécie dominante foi Phacus acuminatus das Euglenophyceae. Os índices de diversidade e similaridade foram classificados como alto, moderado e baixo em relação aos três hidroperíodos registrados, durante o ciclo anual de 2004-2005. O reservatório exibiu alta condutividade elétrica (290-550 µS.cm-1), pH alcalino (7.3-9.4), temperatura média de 28 °C, concentrações de oxigênio dissolvido variando entre 3.29 mg.L-1 a 7.6 mg.L-1 e maior concentração de nutrientes no fundo do reservatório (ortofosfato, 0.22-0.62 mg.L-1), com tendência geral ao estado oligo-mesotrófico durante o período de amostragens. A clorofila a flutuou de um mínimo de 1.34 µg.L-1 no fundo em Abril, 2005 e um máximo de 14.3 µg.L-1 no meio da coluna d'água em Setembro, 2004. O reservatório é um ambiente oligo-mesotrófico característico.
Assuntos
Animais , Clorofila/análise , Monitoramento Ambiental , Água Doce/análise , Fitoplâncton/classificação , Biomassa , Brasil , Físico-Química , Densidade Demográfica , Estações do AnoRESUMO
We investigated the histochemical positivity to NADPH-diaphorase, which reveals nitric oxide synthase activity, in area 17 of rats malnourished early in life, both in the post-weaning period (group M1), and in adulthood after nutritional recovering (group M2). Control pups (C1 and C2 groups) received ad libitum after weaning the same diets as their mothers. Rats of group M2 were nutritionally recovered by receiving the control diet from post-natal day 42 until adulthood. Aldehyde-fixed sections (200-microm thick) through area 17 were processed for NADPH-diaphorase histochemistry following the malic enzyme indirect method. The features of NADPH-diaphorase-containing neurons of area 17 of malnourished young (M1) and adult (M2) rats were analyzed quantitatively in comparison to the matched groups C1 and C2. Permanent changes, represented by increase in the density and dendritic field areas of NADPH-diaphorase-positive cells, and transitory ones, represented by decreased values of soma areas, were observed in area 17 of the M1 and M2 cases. However, some other features, such as dendritic branch angle and number of dendrites per cell in the gray matter, remained unchanged after malnutrition. Thus, the findings indicate a possible relationship between early malnutrition and alterations in nitric oxide synthase-containing cells in the visual cortex. Physiological implications of these data may be related to synaptic plasticity and refinement of developmental brain circuits.
Assuntos
Tamanho Celular/fisiologia , NADPH Desidrogenase/metabolismo , Neurônios/patologia , Óxido Nítrico Sintase/metabolismo , Distúrbios Nutricionais/complicações , Córtex Visual/anormalidades , Córtex Visual/crescimento & desenvolvimento , Fatores Etários , Animais , Animais Recém-Nascidos/anormalidades , Animais Recém-Nascidos/metabolismo , Peso Corporal/fisiologia , Contagem de Células , Dendritos/enzimologia , Dendritos/patologia , Feminino , Alimentos Formulados/efeitos adversos , Plasticidade Neuronal/fisiologia , Neurônios/enzimologia , Distúrbios Nutricionais/enzimologia , Distúrbios Nutricionais/patologia , Gravidez , Ratos , Ratos Wistar , Recuperação de Função Fisiológica/fisiologiaRESUMO
This is the first report of the effects of malnutrition during brain development on biocytin-labelled axon terminals and histochemical pattern of NADPH-diaphorase (NADPH-d)-containing neurons in area 17 of the adult rat. Wistar rats (n = 6) were submitted early in life (from gestation up to 42 days of age) to a multideficient diet (the 'regional basic diet' (RBD) of low-income human populations of north-east Brazil, containing only 8% protein). From day 43 up to adulthood (135-212 days), they were switched to a commercial laboratory chow diet (Purina do Brasil Ltda), with 22% protein. These animals were compared to control rats (n = 11), fed the laboratory chow diet until adulthood. The brains of four adult malnourished and five controls were processed according to the indirect method of the malic enzyme to reveal NADPH-d-containing neurons. Five other adult subjects (three controls and two malnourished) received iontophoretic injections of the tracer biocytin in area 17and were processed according to the glucose oxidase-DAB-nickel protocol in order to visualize axon terminals filled with biocytin. Three other control rats were processed for both techniques. In these last brains, no double-labelled cells could be found, suggesting that the NADPH-d-containing-neurons and the biocytin-labelled ones belong to different groups of cells, in area 17. The appendages of the NADPH-d-positive cells showed minor qualitative and quantitative differences between undernourished and control rats. The soma area of these cells was reduced in the white matter of malnourished rats, as compared to the controls (468.6 ± 54.3 µm(2); n = 4 and 515.4 ± 30.5 µm(2);n = 8, respectively; p < 0.05). The cell density (cells/mm(2)) was greater in the malnourished group than in the control, both at the grey matter (16.6 ± 4.4; n = 4 and 11.3 ± 4.3; n = 8, respectively; p < 0.05) and at the white matter (55.9 ± 15.7; n = 4 and 24.4 ± 8.5; n = 8; p < 0.005). The number of potential synaptic sites in the biocytin-labelled axon terminals was reduced as compared to the control (126 ± 33 boutons/mm, n = 32 and 160 ± 37; n = 30, respectively; p < 0.01). The results indicate that the rat area 17 is affected differently by early malnutrition, regarding biocytin-labelled axon terminals, on the one hand, and NADPH-d-containing neurons, on the other. Concerning these last cells, the data also suggest that they are less sensitive to the injury represented by early malnutrition.