Yeasts Occurring in Surface and Mouth Cavity of Two Chelonian Species, Podocnemis expansa Schweigger and P. unifilis Troschel (Reptilia: Chelonia: Pelomedusidae), in the Javaés River Border of Araguaia National Park in Brazil

Thirty-eight specimens of free-ranging Podocnemis expansa (Amazon turtle) and 22 of P. unifilis (Tracajá) were screened for yeast isolation from surface (plastron, skin, and nails), eye, and mouth cavity. A hundred and eighteen yeast isolates belonging to 39 species were obtained. Debaryomyces hansenii, Candida galli, C. sake, and Rhodotorula mucilaginosa were the most frequent species isolated from these chelonians. Species diversity measured by Shannon's index was shown to be low and a degree of dominance could be detected as species known as potential pathogens were commonly isolated. The effective number of species in plastron of P. expansa was higher than in mouth samples, but not in P. unifilis probably due to dietary factors. P. expansa animals were captured on the beaches, and the superficial yeast populations may include terrestrial species. P. unifilis animals were captured in the water and the yeasts from superficial sites may represent species from river water

Lipolytic Enzymes with Hydrolytic and Esterification Activities Produced by Filamentous Fungi Isolated from Decomposition Leaves in an Aquatic Environment

Microbial lipases are prominent biocatalysts able to catalyze a wide variety of reactions in aqueous and nonaqueous media. In this work, filamentous fungi isolated from leaves decomposed in an aquatic environment were screened for lipase production with hydrolytic activity and esterification. Agar plates with Tween 20 and Rhodamine B were used for selection, while submerged cultures with olive oil were subsequently used to select 38 filamentous fungi. Trichoderma harzianum, Fusarium solani, Trichoderma harzianum F5, and Penicillium sp. F36 were grown in six different culture media. F. solani presented the highest lipase production (2.37 U/mL) with esterification activity of 0.07 U/mL using medium composed of (g.L-1) KH2PO4 1.00, MgSO4 H2O 1.123, and CuSO4 0.06. Supplementation of this culture medium with organic nitrogen sources increased lipase production by 461.3% using tryptone and by 419.4% using yeast extract. Among the vegetable oils from the Amazon region, degummed cotton oil induced lipase production up to 8.14 U/mL. The lipase produced by F. solani F61 has great potential to application in conventional processes and biodiesel production by transesterification of vegetable oils, as well as food industries in the production of fatty acid esters by hydrolysis and esterification. © 2019 D. B. Mendes et al

Methane, Microbes and Models in Amazonian Floodplains: State of the Art and Perspectives

Amazon floodplain ecosystems include open water and intermittent flood forest and agricultural systems with different water types. They are a significant natural source of methane (CH4) in the tropics. When soils are flooded and become anoxic, CH4 is produced by methanogenesis, while microbially mediated aerobic and anaerobic oxidation of CH4 serves as the primary biological sink of this greenhouse gas. Measurements of rates and controls on CH4 production and emission in the Amazon basin mainly come from studies on individual wetlands and floodplain lakes. Similarly, microbial communities in those Amazon floodplain habitats have been studied on individual lakes based on sequence-specific DNA analysis. Existing biogeochemical ecosystem models of CH4 from the Amazon floodplains focus on soil properties or involve factors such as pH, redox potentials, or substrates. None of these models incorporate appropriate seasonal inundation; neither the microbiota does it as a component. In this sense, our chapter will highlight how the important efforts already contributed to understand the CH4 emission and its connections with abiotic and biotic factors in Amazon floodplains, as well as emphasize the need of encouraging cooperation and exchange of experience between research teams by using different approaches and scientific methods

CHANGES IN PHYSICO-CHEMICAL PROPERTIES OF TOPSOIL IN RESPONSE TO AGRICULTURE WITH SOYBEANS IN THE "VÁRZEA" OF TOCANTINS

O uso do solo com cultivos anuais durante longo tempo, especialmente quando são utilizados manejos não conservacionistas, como arações e gradagens, normalmente são responsáveis pela degradação mais intensa de suas propriedades. Este trabalho avaliou as propriedades do solo em três áreas sob cultivo agrícola e uma área nativa de Cerrado, verificando as alterações ocorridas nos atributos físico-químicos do solo após dois, cinco e oito anos sob plantio de soja. As amostras de solo foram coletadas na Fazenda Praia Alta, no município de Lagoa da Confusão - TO, onde a soja é cultivada no período de entressafra (maio-junho), em várzea irrigada, sob regime de subirrigação. A análise físico-química do solo quantificou pH, matéria orgânica (MO), P, S, K, Ca, Mg, Al, H + Al, CTC, SB, Na, Zn, B, Cu, Fe, Mn, argila, silte e areia. Os resultados mostraram evidências que o tempo de uso do solo com agricultura tecnificada, influencia as propriedades do solo; o tempo de cultivo do solo parece influenciar as modificações nos atributos naturais de áreas de várzea alagável no Cerrado.Palavras-chave: nutrientes, propriedades do solo, plantio direto.The use of land with annual crops for a long time, especially when non conservation managements are used, such as plowing and harrowing, is usually responsible for more intense degradation of their properties. This paper evaluated soil properties in three areas of agriculture and a native Cerrado soil, in order to understand the modification on chemical properties of soils after five and eight years of soy plantation. Soil samples were collected in Praia Alta Farm in Lagoa da Confusão – TO municipality, where soy is cultivated during off-season (May-June) in ‘varzea’ lowlands using sub-irrigation. Chemical analysis of soil measured pH, organic matter (MO), P, S, K, Ca, Mg, Al, H + Al, cation exchange capacity, SB, Na, Zn, B, Cu, Fe, Mn, clay, silt and sand. Results showed evidence that the time of cultivation with technified agriculture influences soil properties. Time of cultivation seems to influence the modification in soil properties in wetlands or ‘varzea’ in Cerrado.Keywords: nutrients, soil properties, no-tillage

Plant litter dynamics in the forest-stream interface: Precipitation is a major control across tropical biomes

Riparian plant litter is a major energy source for forested streams across the world and its decomposition has repercussions on nutrient cycling, food webs and ecosystem functioning. However, we know little about plant litter dynamics in tropical streams, even though the tropics occupy 40% of the Earth's land surface. Here we investigated spatial and temporal (along a year cycle) patterns of litter inputs and storage in multiple streams of three tropical biomes in Brazil (Atlantic forest, Amazon forest and Cerrado savanna), predicting major differences among biomes in relation to temperature and precipitation regimes. Precipitation explained most of litter inputs and storage, which were generally higher in more humid biomes (litterfall: 384, 422 and 308 g m-2 y-1, storage: 55, 113 and 38 g m-2, on average in Atlantic forest, Amazon and Cerrado, respectively). Temporal dynamics varied across biomes in relation to precipitation and temperature, with uniform litter inputs but seasonal storage in Atlantic forest streams, seasonal inputs in Amazon and Cerrado streams, and aseasonal storage in Amazon streams. Our findings suggest that litter dynamics vary greatly within the tropics, but point to the major role of precipitation, which contrasts with the main influence of temperature in temperate areas. © 2017 The Author(s)

Estudos sazonais de aspectos limnólogicos de um fragmento florestal inundado na Planície do Araguaia, Tocantins, Brasil

Ipucas são ecossistemas de fragmentos florestais naturais, ocorrendo particularmente na planície do Araguaia. Apresenta grande influência dos pulsos de inundação que ocorrem no período chuvoso, pois permanecem inundadas durante este período e como ambientes terrestres no período seco. O estudo objetivou avaliar a variação temporal de fatores limnológicos em uma Ipuca, no município de Lagoa da Confusão, Tocantins, através de coletas mensais entre Dezembro/2014 e Agosto/2015. As variáveis mensuradas foram: transparência através do disco Secchi, turbidez (NTU), oxigênio dissolvido (mg/L), temperatura (°C), potencial hidrogeniônico - pH, sólidos totais dissolvidos (ppm), condutividade elétrica (µS/cm), amônia – NH3 (mg/L), nitrito – NO­2 (mg/L), nitrato – NO3 (mg/L), ortofosfato - P (mg/L), clorofila-? (µg/L) e profundidade da lamina d’água (cm). O total transparência da água e os baixos valores de turbidez demonstram a importância da precipitação nestes parâmetros, assim como a estrutura florestal da “Ipuca” suporta os valores encontrados. A temperatura da água das “Ipucas” foi influenciada pelas estações do ano, principalmente pela quantidade de ventos. O oxigênio dissolvido esteve diretamente relacionado a clorofila-?. A concentração dos nutrientes analisados apresentou grandes oscilações, provavelmente devido à rápida incorporação destes pelas comunidades aquáticas. Contudo, foi observada uma homogeneização dos parâmetros físico-químicos no decorrer do tempo amostral

OCORRÃNCIA DE Escherichia coli MULTIRRESISTENTES A ANTIMICROBIANOS NAS PRINCIPAIS PRAIAS DO RESERVATÃRIO DE LAJEADO â TO

A exposição humana à água contaminada por material fecal, seja por ingestão ou por atividades recreacionais, é importante mecanismo de transmissão de patógenos gastrintestinais, sendo a Escherichia coli considerada um dos principais patógenos responsáveis por gastroenterite em crianças no Brasil. Este trabalho tem por objetivo detectar e quantificar Escherichia coli nas principais praias do reservatório da UHE Lajeado e verificar o perfil de resistência a antimicrobianos das cepas isoladas. Para a detecção e contagens de coliformes totais e Escherichia coli foi utilizada a técnica do substrato cromogênico e colônias típicas foram identificadas utilizando o kit API20E. A suscetibilidade a antimicrobianos foi testada utilizando a técnica de difusão em discos de papéis impregnados com antibióticos. Os maiores índices de contaminação fecal foram obtidos em praias urbanas, com o número mais provável de Escherichia coli entre 95,8/100 mL e 133,2/100 mL. Estes valores estão abaixo dos limites preconizados pela legislação brasileira. Pode-se observar uma elevada freqüência de resistência a Tetraciclina (69%), Sulfametaxazol/trimetoprim (44 %) e Ampicilina (21%). A contaminação fecal das praias fluviais no reservatório são balneáveis, de acordo com a legislação. O isolamento de cepas de E. coli multirresistentes, no entanto, aponta riscos à saúde humana que requerem ser melhor monitorado

Podocnemis expansa Schweigger and P. unifilis Troschel (Reptilia: Chelonia: Pelomedusidae), in the Javaés River Border of Araguaia National Park in Brazil

Thirty-eight specimens of free-ranging Podocnemis expansa (Amazon turtle) and 22 of P. unifilis (Tracajá) were screened for yeast isolation from surface (plastron, skin, and nails), eye, and mouth cavity. A hundred and eighteen yeast isolates belonging to 39 species were obtained. Debaryomyces hansenii, Candida galli, C. sake, and Rhodotorula mucilaginosa were the most frequent species isolated from these chelonians. Species diversity measured by Shannon's index was shown to be low and a degree of dominance could be detected as species known as potential pathogens were commonly isolated. The effective number of species in plastron of P. expansa was higher than in mouth samples, but not in P. unifilis probably due to dietary factors. P. expansa animals were captured on the beaches, and the superficial yeast populations may include terrestrial species. P. unifilis animals were captured in the water and the yeasts from superficial sites may represent species from river water