Distribution of periphytic algae in wetlands (Palm swamps, Cerrado), Brazil / Distribuicao de algas perifiticas em areas umidas (Veredas, Cerrado), Brasil

The distribution of periphytic algae communities depends on various factors such as type of substrate, level of disturbance, nutrient availability and light. According to the prediction that impacts of anthropogenic activity provide changes in environmental characteristics, making impacted Palm swamps related to environmental changes such as deforestation and higher loads of nutrients via allochthonous, the hypothesis tested was: impacted Palm swamps have higher richness, density, biomass and biovolume of epiphytic algae. We evaluated the distribution and structure of epiphytic algae communities in 23 Palm swamps of Goiás State under different environmental impacts. The community structure attributes here analyzed were composition, richness, density, biomass and biovolume. This study revealed the importance of the environment on the distribution and structuration of algal communities, relating the higher values of richness, biomass and biovolume with impacted environments. Acidic waters and high concentration of silica were important factors in this study. Altogether 200 taxa were identified, and the zygnemaphycea was the group most representative in richness and biovolume, whereas the diatoms, in density of studied epiphyton. Impacted Palm swamps in agricultural area presented two indicator species, Gomphonema lagenula Kützing and Oedogonium sp, both related to mesotrophic to eutrophic conditions for total nitrogen concentrations of these environments.

A distribuição de comunidades de algas perifíticas depende de vários fatores, como tipo de substrato, nível de distúrbio, disponibilidade de nutrientes e luz. De acordo com a predição de que impactos de ação antrópica proporcionam alterações nas características ambientais – tornando Veredas impactadas relacionadas a alterações ambientais, como desmatamentos e maiores cargas de nutrientes via alóctone –, a hipótese testada foi: Veredas impactadas apresentam maiores riqueza, densidade, biomassa e biovolume de algas epifíticas. Avaliaram-se a distribuição e a estruturação de comunidades de algas epifíticas em 23 Veredas do Estado de Goiás sob diferentes impactos ambientais. Os atributos da estrutura de comunidade avaliados foram composição, riqueza, densidade, biomassa e biovolume. Este estudo revelou a importância das características ambientais na distribuição e na estruturação das comunidades de algas, relacionando os maiores valores de riqueza, biomassa e biovolume dos organismos aos ambientes impactados. Águas ácidas e altas concentrações de sílica foram fatores importantes no estudo. Ao todo, foram identificados 200 táxons, sendo as zignemafíceas o grupo mais representativo em riqueza e biovolume, enquanto as diatomáceas, as mais representativas em densidade do epifíton estudado. Veredas impactadas em área de agropecuária apresentaram duas espécies indicadoras, Gomphonema lagenula e Oedogonium sp., ambas relacionadas com condições mesotróficas a eutróficas, para concentrações de nitrogênio total desses ambientes.

Low water hardness and pH affect growth and survival of silver catfish juveniles / Baixa dureza da água e pH afetam o crescimento e a sobrevivência de juvenis de jundiá

The objective of this study was to investigate the effects of exposure to low water hardness (0, 25 and 50mg CaCO3L-1) into the 6.0-8.0 pH range to silver catfish juveniles (Rhamdia quelen) survival and growth after 32 days. Juveniles kept at zero water hardness presented higher mortality at pH 7.0 and 8.0 than those submitted to other treatments. Weight of juveniles exposed to pH 6.0 and zero water hardness was significantly higher than those kept at the same water hardness and other pH. Survival and growth of juveniles exposed to 25 and 50mg CaCO3 L-1 was not affected in the 6.0-8.0 pH range. Therefore, the best water hardness for silver catfish juveniles growth is 25-50mg CaCO3 L-1 and at low water hardness (next zero) pH must be reduced.

O objetivo deste estudo foi investigar os efeitos da exposição em baixas durezas da água (0; 25 e 50mg CaCO3 L-1) na faixa de pH 6,0-8,0 no crescimento e na sobrevivência de juvenis de jundiás (Rhamdia quelen). Os juvenis foram expostos aos tratamentos durante 32 dias. Os indivíduos mantidos em dureza zero da água apresentaram maior mortalidade em pH 7,0 e 8,0 do que aqueles submetidos aos outros tratamentos. O peso dos juvenis expostos ao pH 6,0 com zero dureza da água foram significativamente maiores do que aqueles mantidos na mesma dureza e em outras faixas de pH. A sobrevivência e o crescimento dos indivíduos expostos em 25 e 50mg CaCO3L-1 não foi afetado na faixa de pH 6,0-8,0. Portanto, a melhor dureza da água para o crescimento e de juvenis de jundiá é 25-50mg CaCO3 L-1 e em baixa dureza da água (próxima a zero) o pH deve ser reduzido.

Calcium fluxes in Hoplosternum littorale (tamoatá) exposed to different types of Amazonian waters

Fishes that live in the Amazonian environment may be exposed to several kinds of waters: "black waters", containing high dissolved organic carbon and acidic pH, "white waters", with ten fold higher Ca2+ concentrations than black waters and neutral pH, and "clear waters", with two fold higher Ca2+ concentrations than black waters and also neutral pH. Therefore, the aim of the present study was to analyze Ca2+ fluxes in the facultative air-breather Hoplosternum littorale (tamoatá) exposed to different Amazonian waters. Fishes were acclimated in well water (similar to clear water) and later placed in individual chambers for Ca2+ fluxes measurements. After 4 h, water from the chambers was replaced by a different type of water. Transfer of tamoatás to ion-poor black or acidic black water resulted in net Ca2+ loss only in the first 2 h of experiment. However, transfer from black or acidic black water to white water led to only net Ca2+ influxes. The results obtained allowed us to conclude that transfer of tamoatás to ion-poor waters (black and acidic black water) led to transient net Ca2+ loss, while the amount of Ca2+ in the ion-rich white water seems adequate to prevent Ca2+ loss after transfer. Therefore, transfer of tamoatás between these Amazonian waters does not seem to result in serious Ca2+ disturbance.(AU)

Os peixes que vivem na Amazônia são expostos a vários tipos de água: águas pretas, contendo grande quantidade de carbono orgânico dissolvido, águas brancas, com concentração de Ca2+ dez vezes maior que as águas pretas e pH neutro, e águas claras, com concentração de Ca2+ duas vezes maior que as águas pretas e pH também neutro. Dessa forma, o objetivo deste trabalho foi analisar o fluxo de Ca2+ no peixe de respiração aérea facultativa Hoplosternum littorale (tamoatá) exposto a diferentes tipos de águas amazônicas. Os peixes foram aclimatados em água de poço artesiano (semelhante à água clara) e depois colocados individualmente em câmaras para medir o fluxo de Ca2+. Após 4 h, a água das câmaras foi trocada por um tipo diferente de água. A transferência do tamoatá das águas pobres em íons água preta e preta ácida ou da água branca, rica em íons, para as águas preta e preta ácida, pobres em íons, resulta em uma perda de Ca2+ apenas nas duas primeiras horas de experimento. Entretanto, a transferência da água preta e preta ácida, para a água branca resulta em um influxo de Ca2+. Os resultados obtidos nos permitem concluir que a transferência do tamoatá para as águas preta e preta ácida, pobres em íons, leva a uma temporária perda de Ca2+, e a quantidade de Ca2+ na água branca, rica em íons, é adequada para prevenir sua perda após a transferência. Sendo assim, a transferência do tamoatá entre as águas estudadas não resulta em sérios distúrbios no Ca2+.(AU)

Electron microscopic studies on bactericidal effects of electrolyzed acidic water on bacteria derived from kendo protective equipment

<p><b>OBJECTIVES</b>Kendo protective equipment is used without washing for a long time.Staphylococcus saprophyticus, Micrococcus luteus, andBacillus sphaericus are frequently isolated from the mask ('men' in Japanese) of kendo protective equipment during one year. To investigate the bactericidal effects of electrolyzed acidic water on these three bacteria, we observed their cellular structures by electron microscopy after treatment with such water.</p><p><b>METHODS</b>Each bacterium isolated from 'men' was treated with electrolyzed acidic water and then observed under scanning and transmission electron microscopes.</p><p><b>RESULTS</b>WhenS. saprophyticus was treated with electrolyzed acidic water and its cellular structures were observed under a transmission electron microscope, ghost cytoplasm was observed, in which no ribosomal granules or fibrous DNA structures were present, and the cell wall inner layer was detached from the outer layer. Under a scanning electron microscope, the structure of the cell wall surface layer was wrinkled, and round pores were partially formed, indicating that the cytoplasmic structures were flushed out of the cells treated with electrolyzed acidic water through the pores formed in the cell wall. InM. luteus, the destruction of ribosomal granules and that of DNA fibers were observed to be similar to those ofS. saprophyticus. ForB. sphaericus, the effect of electrolyzed acidic water was investigated using vegetative cells. A dissociation between the cytoplasm and cell wall wrinkled the cell surface layer.</p><p><b>CONCLUSION</b>On the basis of above findings, electrolyzed acidic water was found to destroy the cellular structures of the three bacterial species frequently isolated from kendo men within a short time. Electrolyzed acidic water may be useful for disinfecting of kendo equipment.</p>

Electron Microscopic Studies on Bactericidal Effects of Electrolyzed Acidic Water on Bacteria Derived from Kendo Protective Equipment

Objectives: Kendo protective equipment is used without washing for a long time. Staphylococcus saprophyticus, Micrococcus luteus, and Bacillus sphaericus are frequently isolated from the mask (‘men’ in Japanese) of kendo protective equipment during one year. To investigate the bactericidal effects of electrolyzed acidic water on these three bacteria, we observed their cellular structures by electron microscopy after treatment with such water. Methods: Each bacterium isolated from ‘men’ was treated with electrolyzed acidic water and then observed under scanning and transmission electron microscopes. Results: When S. saprophyticus was treated with electrolyzed acidic water and its cellular structures were observed under a transmission electron microscope, ghost cytoplasm was observed, in which no ribosomal granules or fibrous DNA structures were present, and the cell wall inner layer was detached from the outer layer. Under a scanning electron microscope, the structure of the cell wall surface layer was wrinkled, and round pores were partially formed, indicating that the cytoplasmic structures were flushed out of the cells treated with electrolyzed acidic water through the pores formed in the cell wall. In M. luteus, the destruction of ribosomal granules and that of DNA fibers were observed to be similar to those of S. saprophyticus. For B. sphaericus, the effect of electrolyzed acidic water was investigated using vegetative cells. A dissociation between the cytoplasm and cell wall wrinkled the cell surface layer. Conclusion: On the basis of above findings, electrolyzed acidic water was found to destroy the cellular structures of the three bacterial species frequently isolated from kendo men within a short time. Electrolyzed acidic water may be useful for disinfecting of kendo equipment.