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Abstract Coffea sp. is cultivated in many tropical countries. Brazil has always adopted intensive agricultural practices, but organic coffee farming is an alternative system based on the non-use of agrochemicals and the rational management of soils. Metabarcoding 16S analysis using next-generation sequencing has been developed to identify and compare the diversity of the Coffea arabica L. rhizospheric bacterial community in two farming areas in São Paulo, Brazil. Dourado uses conventional farming, while Ribeirão Corrente uses organic. We found broad taxonomic composition, with sequences from 24 phyla, 55 classes, 61 orders, 146 families, and 337genus. The three most abundant phyla were Proteobacteria (38.27%), Actinobacteria (15.56%), and Acidobacteria (16.10%). In organic farming, the top 3 were the family Sphingomonadaceae, order Rhizobiales, genus Nocardioides, and Gp6. The genus Gp2 and the phylum Candidatus Saccharibacteria were the most abundant OTUs exclusively present in conventional farming. In the organic farming practice, Proteobacteria, Actinobacteria, and Acidobacteria were also present among the exclusive OTUs; we also found OTUs belonging to Bacteroidetes, Firmicutes, and Verrucomicrobia. Our study indicates a positive effect of organic farming on microbial communities. Fertilization may directly affect soil microbiota, suggesting that a large and active microbial community low in functional diversity might not adapt to new climatic conditions. A diverse community could provide better resilience to environmental changes, improving the productivity of this important crop.

Resumo Coffea sp. é cultivada em muitos países tropicais. O Brasil sempre adotou práticas agrícolas intensivas, mas a cafeicultura orgânica é um sistema alternativo baseado na não utilização de agrotóxicos e no manejo racional dos solos. A análise Metabarcode 16S utilizando o sequenciamento de última geração foi desenvolvida para identificar e comparar a diversidade da comunidade bacteriana rizosférica de Coffea arabica L. em duas áreas de cultivo em São Paulo, Brasil. Dourado usa agricultura convencional, enquanto Ribeirão Corrente usa agricultura orgânica. Encontramos ampla composição taxonômica, com sequências de 24 filos, 55 classes, 61 ordens, 146 famílias e 337 gêneros. Os três filos mais abundantes foram Proteobacteria (38,27%), Actinobacteria (15,56%) e Acidobacteria (16,10%). Na agricultura orgânica, os 3 primeiros foram a família Sphingomonadaceae, ordem Rhizobiales, gênero Nocardioides e Gp6. O gênero Gp2 e o filo Candidatus Saccaribacteria foram as OTUs mais abundantes exclusivamente presentes na agricultura convencional. Na prática da agricultura orgânica, Proteobacteria, Actinobacteria e Acidobacteria também estiveram presentes entre as OTUs exclusivas; também encontramos OTUs pertencentes a Bacteroidetes, Firmicutes e Verrucomicrobia. Nosso estudo indica um efeito positivo da agricultura orgânica nas comunidades microbianas. A fertilização pode afetar diretamente a microbiota do solo, sugerindo que uma grande e ativa comunidade microbiana com baixa diversidade funcional pode não se adaptar às novas condições climáticas. Uma comunidade microbiana diversificada poderia proporcionar maior resiliência às mudanças ambientais, melhorando a produtividade desta importante cultura agrícola.

https://doi.org/10.1590/1519-6984.274070

Chemical composition and biological activities of essential oil from flowers of Psidium guajava (Myrtaceae)
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Fernandes, C. C.

; Rezende, J. L.

; Silva, E. A. J.

; Silva, F. G.

; Stenico, L.

; Crotti, A. E. M.

; Esperandim, V. R.

; Santiago, M. B.

; Martins, C. H. G.

; Miranda, M. L. D.

Brazilian Journal of Biology

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sep 2021, Volume 81 N. 3 Pages 728 - 736

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo Xylella fastidiosa é uma bactéria patogênica que vive dentro dos vasos do xilema hospedeiro, onde forma um biofilme responsável por interromper a passagem de água e nutrientes. Pectobacterium carotovorum é uma bactéria Gram-negativa que causa não só podridão macia em várias plantas hospedeiras, mas também canela-preta na batata por degradação da parede celular da planta. A doença de Chagas, causada pelo Trypanosoma cruzi, é comumente tratada com nifurtimox e benzonidazol, duas drogas que causam vários efeitos colaterais. Como resultado, o uso de produtos naturais para o tratamento de doenças bacterianas e negligenciadas aumentou nos últimos anos e as plantas continuam sendo uma alternativa promissora para o desenvolvimento de novos medicamentos. Portanto, este estudo teve como objetivo determinar, pela primeira vez, a composição química do óleo essencial de flores de Psidium guajava (PG-EO) e avaliar suas propriedades anti-Xylella fastidiosa, anti-Pectobacterium carotovorum, anti-Trypanosoma cruzi e citotóxica in vitro. PG-EO foi obtido por hidrodestilação em um aparelho Clevenger, enquanto sua composição química foi determinada por cromatografia em fase gasosa com detecção por ionização por chama (CG-DIC) e por cromatografia em fase gasosa acoplada à espectrometria de massa (CG-EM). Os principais compostos identificados no PG-EO foram α-cadinol (37,8%), β-cariofileno (12,2%), nerolidol (9,1%), α-selineno (8,8%), β-selineno (7,4%) e óxido de cariofileno (7,2%). Os resultados mostraram que o PG-EO apresentou forte atividade tripanocida contra as formas tripomastigotas de T. cruzi (CI50 = 14,6 μg/mL), promissora atividade antibacteriana contra X. fastidiosa (MIC = 12,5 μg/mL) e P. carotovorum (MIC = 62,5 μg/mL) e citotoxicidade moderada contra células epiteliais aderentes (LLCMK2) na faixa de concentração (CC50 = 250,5 μg/mL). Em suma, o PG-EO pode ser considerado uma nova fonte de compostos bioativos para o desenvolvimento de pesticidas e drogas tripanocidas.

Abstract Xylella fastidiosa is a plant-pathogenic bacterium that lives inside host xylem vessels, where it forms biofilm which is believed to be responsible for disrupting the passage of water and nutrients. Pectobacterium carotovorum is a Gram-negative plant-specific bacterium that causes not only soft rot in various plant hosts, but also blackleg in potato by plant cell wall degradation. Chagas disease, which is caused by Trypanosoma cruzi, has been commonly treated with nifurtimox and benzonidazole, two drugs that cause several side effects. As a result, the use of natural products for treating bacterial and neglected diseases has increased in recent years and plants have become a promising alternative to developing new medicines. Therefore, this study aimed to determine, for the first time, the chemical composition of essential oil from Psidium guajava flowers (PG-EO) and to evaluate its in vitro anti-Xylella fastidiosa, anti-Pectobacterium carotovorum, anti-Trypanosoma cruzi and cytotoxic activities. PG-EO was obtained by hydrodistillation in a Clevenger apparatus while its chemical composition was determined by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Major compounds identified in PG-EO were α-cadinol (37.8%), β-caryophyllene (12.2%), nerolidol (9.1%), α-selinene (8.8%), β-selinene (7.4%) and caryophyllene oxide (7.2%). Results showed that the PG-EO had strong trypanocidal activity against the trypomastigote forms of Trypanosoma cruzi (IC50 = 14.6 μg/mL), promising antibacterial activity against X. fastidiosa (MIC = 12.5 μg/mL) and P. carotovorum (MIC = 62.5 μg/mL), and moderate cytotoxicity against LLCMK2 adherent epithelial cells in the concentration range (CC50 = 250.5 μg/mL). In short, the PG-EO can be considered a new source of bioactive compounds for the development of pesticides and trypanocide drugs.

https://doi.org/10.1590/1519-6984.230533 1466 downloads

Screening of Alkaloid-Producing Endophytic Penicillium Strains from Amazon Medicinal Plants by Electrospray Ionization Mass Spectrometry (ESI-MS) and Principal Component Analysis (PCA)
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Silva-Filho, Francinaldo A. da

; Souza, Marjory M. M. de

; Rezende, Gabriel O.

; Silva, Felipe M. A. da

; Cruz, Jeferson C. da

; Silva, Gilvan F. da

; Souza, Afonso D. L. de

; Souza, Antonia Q. L. de

Journal of the Brazilian Chemical Society

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sep 2021, Volume 32 N. 9 Pages 1832 - 1839

Abstract: En | Text: En | PDF: En

The genus Penicillium is among the most promising alkaloid-producing fungal and therefore plays an important role in terms of producing molecules with biotechnological potential. Thus, in order to identify alkaloid-producing fungi, 25 endophytic Penicillium strains previously isolated from Amazon medicinal plants were subject to an integrative approach based on direct infusion positive electrospray ionization mass spectrometry (ESI-MS) and principal component analysis (PCA). The multivariate analysis pointed paxiline (1), glandicoline B (2), roquefortine C (3), and oxaline (5) as responsible for the segregation of three promising alkaloid-producing groups, been these groups constituted for P. chrysogenum, P. oxalicum, P. paxilli, and P. rubens strains. These alkaloids and the glandicoline A (4) were tentatively identified by multiple-stage mass spectrometry. In addition, compounds 1 and 2 were isolated and confirmed by using 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. Overall, the chemical profile analysis by ESI-MS along with PCA provided a simple and effective approach to screening alkaloid-producing Penicillium strains for biotechnological applications.

https://doi.org/10.21577/0103-5053.20210074 20 downloads

Unexpected Rearrangement and Aromatization on Dehydration Reaction of the Bioactive Diterpenequinone 7α-Hydroxyroyleanone
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Leitão, Gilda G.

; Pinheiro, Aline G. L.

; Rezende, Victor L. D.

; Silva, Raphael S. F.

; Paula, Leonardo R.

; Soares, Deivid C.

; Saraiva, Elvira M.

Journal of the Brazilian Chemical Society

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mar 2020, Volume 31 N. 3 Pages 597 - 602

Abstract: En | Text: En | PDF: En

7a-Hydroxyroyleanone is a bioactive diterpene isolated from leaves of Tetradenia riparia, active against tuberculosis and T. cruzi. In order to use this compound as starting material for the synthesis of compounds with enhanced bioactivity we aimed the dehydration of the 7-alpha-hydroxyl group of royleanone. The reaction performed in acetic acid and hydrochloric acid under reflux gave an unexpected chlorinated naphtoquinone, with aromatization and opening of one of the rings of the starting material, as major product, besides 6,7-dehydroroyleanone and a complex mixture of other products. The reaction products were purified by high-speed countercurrent chromatography with hexane-acetonitrile 1:1. Compounds were tested for their anti-leishmanial activity (L. amazonensis) pointing out a potential leishmanicidal agent which may favor the development of more effective therapies.

https://doi.org/10.21577/0103-5053.20190223 288 downloads

Synthesis and Evaluation of Biocide and Cetane Number Improver Additives for Biodiesel from Chemical Changes in Triacylglycerides
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Costa, Kênia P.

; Valle, Stella F. do

; Santos, Thayana F. L. dos

; Rangel, Ellen T.

; Pinto, Angelo C.

; Suarez, Paulo A. Z.

; Rezende, Michelle J. C.

Journal of the Brazilian Chemical Society

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dec 2018, Volume 29 N. 12 Pages 2605 - 2615

Abstract: En | Text: En | PDF: En

Biodiesel demand is increasing all over the world and the inhibition of microbial growth during the storage of this biofuel is extremely important. There are few studies involving the evaluation of biocides specifically for biodiesel. In the present work, we synthesized and evaluated a set of biocide candidates from chemical transformations in triacylglycerides. Samples of pure biodiesel with the products were evaluated against microorganisms which have been isolated from biodiesel/diesel blends (fungi A. niger, A. fumigatus, C. albicans and S. cerevisiae; and bacteria B. subtilis and Acinetobacter sp.). None of the products inhibited the growth of bacteria. Four nitrated derivatives presented fungicidal activity. The nitrated derivatives were also evaluated as cetane number improvers for B7 biodiesel/diesel blend. The nitrates of soybean methoxylated ethylene glycol esters increased the cetane number by more than three points. Despite showing modest biocide activity, the results can guide the planning of new products from triacylglycerides.

https://doi.org/10.21577/0103-5053.20180140 903 downloads

Evaluating the Potential of Biodiesel Production through Microalgae Farming in Photobioreactor and High Rate Ponds from Wastewater Treatment
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Pinho, David M. M.

; Oliveira, Renato S.

; Santos, Vitor M. L. dos

; Marques, Welington F.

; Pinto, Angelo C.

; Rezende, Michelle J. C.

; Suarez, Paulo A. Z.

Journal of the Brazilian Chemical Society

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dec 2017, Volume 28 N. 12 Pages 2429 - 2437

Abstract: En | Text: En | PDF: En

In the last decade, the research works on microbial as a potential source of lipid for biodiesel production have been growing. In this work, the potential of a sludge from high-rate lagoons in urban sewage treatment, composed mainly by Chlorella sp., as oil source for biodiesel production, was studied. The potential of Chlorella sp. growth in photobioreactor under controlled conditions was also investigated. Low lipid content (up to 3%) was observed in both cases. The composition of both oils showed high amount of fatty acids and fatty acid based compounds, however there are also other non-fatty acid based lipids. Density and viscosity of biodiesel from biosolid oil were determined and the results showed that these physico-chemical properties do not match the specification required for biodiesel. The results showed that sewage sludge from Samambaia treatment station (DF, Brazil) and Chlorella sp. cultivated under the conditions described in this work are not potential sources of fatty material for biodiesel production.

https://doi.org/10.21577/0103-5053.20170097 1155 downloads

Application of Full Factorial Design to Evaluate the Effect of Different Variables on the Stability of Biodiesel:Diesel Blends under Storage Conditions
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Rezende, Michelle J. C.

; Vale, Daniella L.

; Aguiar, Paula F.

; Riehl, Carlos A. S.

; Azevedo, Debora A.

Journal of the Brazilian Chemical Society

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oct 2017, Volume 28 N. 10 Pages 1966 - 1974

Abstract: En | Text: En | PDF: En

Biodiesel is obtained from a renewable source and has been used as an alternative to fossil fuels. It has unsaturated fatty acid methyl esters that can degrade due to oxidation of the double bonds. The instability of biodiesel during storage may cause problems regarding the maintenance and operation of motors. This work evaluated the effect of several variables on the storage conditions of biodiesel:diesel blends. The study was performed using an experimental design, and the variables were water content in biodiesel (0.01, 0.05 and 0.09%), biodiesel content in diesel (5.0, 7.5 and 10.0%), time (15, 30 and 45 days) and temperature (30, 40 and 50 °C). The levels simulated actual Brazilian storage conditions. The degradation was evaluated based on direct measurement of methyl linoleate and methyl oleate in the blends by gas chromatography-mass spectrometry. These unsaturated fatty acid methyl esters are target compounds in the oxidation process. All experiments were carried out in sealed flasks. The results suggest that the restriction of oxygen limited the degradation of biodiesel in blends with higher percentage of the biofuel. The variables temperature, time and water content in biodiesel individually did not affect the degradation process within the range investigated at 95% confidence interval.

https://doi.org/10.21577/0103-5053.20170041 1173 downloads

Calibration of the maximum carboxylation velocity (Vcmax) using data mining techniques and ecophysiological data from the Brazilian semiarid region, for use in Dynamic Global Vegetation Models
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Rezende, L. F. C.

; Arenque-Musa, B. C.

; Moura, M. S. B.

; Aidar, S. T.

; Von Randow, C.

; Menezes, R. S. C.

; Ometto, J. P. B. H.

Brazilian Journal of Biology

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jun 2016, Volume 76 N. 2 Pages 341 - 351

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo A região semiárida do nordeste do Brasil, a Caatinga, é extremamente importante devido à sua biodiversidade e endemismo. Medidas de fisiologia vegetal são cruciais para a calibração de Modelos de Vegetação Globais Dinâmicos (DGVMs) que são atualmente usados para simular as respostas da vegetação diante das mudanças globais. Em um trabalho de campo realizado em uma área de floresta preservada na Caatinga localizada em Petrolina, Pernambuco, medidas de assimilação de carbono (em resposta à luz e ao CO2) foram realizadas em 11 indivíduos de Poincianella microphylla, uma espécie nativa que é abundante nesta região. Estes dados foram utilizados para calibrar a velocidade máxima de carboxilação (Vcmax) usada no modelo INLAND. As técnicas de calibração utilizadas foram Regressão Linear Múltipla (MLR) e técnicas de mineração de dados como Classification And Regression Tree (CART) e K-MEANS. Os resultados foram comparados com o modelo INLAND não calibrado. Verificou-se que a Produtividade Primária Bruta (PPB) simulada atingiu 72% da PPB observada ao usar os valores de Vcmax calibrado, enquanto que o modelo não calibrado obteve-se 42% da PPB observada. Assim, este trabalho mostra os benefícios de calibrar DGVMs usando medidas ecofisiológicas de campo, especialmente em áreas onde os dados de campo são escassos ou inexistentes, como na Caatinga.

Abstract The semiarid region of northeastern Brazil, the Caatinga, is extremely important due to its biodiversity and endemism. Measurements of plant physiology are crucial to the calibration of Dynamic Global Vegetation Models (DGVMs) that are currently used to simulate the responses of vegetation in face of global changes. In a field work realized in an area of preserved Caatinga forest located in Petrolina, Pernambuco, measurements of carbon assimilation (in response to light and CO2) were performed on 11 individuals of Poincianella microphylla, a native species that is abundant in this region. These data were used to calibrate the maximum carboxylation velocity (Vcmax) used in the INLAND model. The calibration techniques used were Multiple Linear Regression (MLR), and data mining techniques as the Classification And Regression Tree (CART) and K-MEANS. The results were compared to the UNCALIBRATED model. It was found that simulated Gross Primary Productivity (GPP) reached 72% of observed GPP when using the calibrated Vcmax values, whereas the UNCALIBRATED approach accounted for 42% of observed GPP. Thus, this work shows the benefits of calibrating DGVMs using field ecophysiological measurements, especially in areas where field data is scarce or non-existent, such as in the Caatinga.

https://doi.org/10.1590/1519-6984.14414 4918 downloads

Diversity of Brazilian Fungi
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Maia, Leonor C.

; Carvalho Júnior, Aníbal A. de

; Cavalcanti, Laise de H.

; Gugliotta, Adriana de M.

; Drechsler-Santos, Elisandro R.

; Santiago, André L.M. de A.

; Cáceres, Marcela E. da S.

; Gibertoni, Tatiana B.

; Aptroot, André

; Giachini, Admir J.

; Soares, Adriene M. da S.

; Silva, Allyne C.G.

; Magnago, Altielys C.

; Goto, Bruno T.

; Lira, Carla R.S. de

; Montoya, Carlos A.S.

; Pires-Zottarelli, Carmen L.A.

; Silva, Danielle K.A. da

; Soares, Dartanhã J.

; Rezende, Diogo H.C.

; Luz, Edna D.M.N.

; Gumboski, Emerson L.

; Wartchow, Felipe

; Karstedt, Fernanda

; Freire, Fernando M.

; Coutinho, Flávia P.

; Melo, Georgea S. N. de

; Sotão, Helen M. P.

; Baseia, Iuri G.

; Pereira, Jadergudson

; Oliveira, Jadson J.S. de

; Souza, João F.

; Bezerra, José L.

; Neta, Lídia S. Araujo

; Pfenning, Ludwig H.

; Gusmão, Luís F.P.

; Neves, Maria A.

; Capelari, Marina

; Jaeger, Melissa C.W.

; Pulgarín, Melissa P.

; Menolli Junior, Nelson

; Medeiros, Priscila S. de

; Friedrich, Raquel C.S.

; Chikowski, Renata dos S.

; Pires, Ricardo M.

; Melo, Roger F.

; Silveira, Rosa M.B. da

; Urrea-Valencia, Salomé

; Cortez, Vagner G.

; Silva, Valéria F. da

Rodriguésia

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2015, Volume 66 N. 4 Pages 1033 - 1045

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo Até 2010, o conhecimento sobre a diversidade de fungos do Brasil estava registrado em publicações esparsas de taxonomia e ecologia e em algumas poucas listas de espécies. Com a publicação do Catálogo de Plantas e Fungos do Brasil, e a disponibilização da lista online, tem sido possível agregar o conhecimento disperso. A versão ora apresentada acrescenta 2.111 nomes de espécies aos 3.608 listados em 2010. São citadas 5.719 espécies de fungos distribuídas em 1.246 gêneros, 102 ordens e 13 divisões, consistindo em considerável aumento em relação a 2010, quando estavam registrados 924 gêneros e 78 ordens. Predominam os Basidiomycota (2.741 espécies, em 22 ordens) e Ascomycota (1.881 espécies, em 41 ordens). A Mata Atlântica possui a maior quantidade de registros, com 3.017 espécies, seguido pela Amazonia (1.050), Caatinga (999), Cerrado (638) e Pampa e Pantanal com 84 e 35 espécies, respectivamente. A região Nordeste tem a maior riqueza (2.617 especies), seguida pelo Sudeste (2.252), Sul (1.995), Norte (1.301) e Centro Oeste (488 espécies). Em relação aos Estados da Federação, São Paulo (1.846 espécies), Pernambuco (1.611) e Rio Grande do Sul (1.377) são os mais diversos.

Abstract Knowledge about the Brazilian fungal diversity was, until 2010, recorded in few taxonomy and ecology publications, as well as in a handful of species lists. With the publication of the Catálogo de Plantas e Fungos do Brasil and the continued availability of an online list, it has been possible to aggregate this dispersed knowledge. The version presented here adds 2,111 species names to the 3,608 listed in 2010. A total of 5,719 species of fungi distributed in 1,246 genera, 102 orders and 13 phyla represents a considerable increase over the last five years, when only 924 genera and 78 orders were registered. Basidiomycota (2,741 species in 22 orders) and Ascomycota (1,881 species in 41 orders) predominate over other groups. The Atlantic Rainforest has the largest number of records, with 3,017 species, followed by Amazon Rainforest (1,050), Caatinga (999), Cerrado (638) and Pampa and Pantanal with 84 and 35 species, respectively. The Northeast region has the greatest richness (2,617 species), followed by Southeast (2,252), South (1,995), North (1,301) and Central-West (488 species). Regarding the States of the Federation, São Paulo with 1,846 species, Pernambuco with 1,611 and Rio Grande do Sul with 1,377 species are the most diverse.

https://doi.org/10.1590/2175-7860201566407 9322 downloads

10.

Administração repetida de doses não tóxicas de monofluoroacetato de sódio não protege contra a intoxicação por este composto em ovinos
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Santos, Ariany C.

; Riet-Correa, Franklin

; Heckler, Rubiane F.

; Lima, Stephanie C.

; Silva, Mariana L.

; Rezende, Renato

; Carvalho, Nilton M.

; Lemos, Ricardo A.A.

Pesquisa Veterinária Brasileira

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jul 2014, Volume 34 N. 7 Pages 649 - 654

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Com o objetivo de avaliar se repetidas doses não tóxicas de monofluoroacetato de sódio (MFA) induzem resistência à intoxicação por essa substância, 18 ovinos foram distribuídos aleatoriamente em dois grupos experimentais de nove animais cada. Os ovinos do Grupo 1 ingeriram doses crescentes não letais de MFA por seis períodos: 0,05mg/kg por 5 dias; 0,08mg/kg por 4 dias; 0,08mg/kg por 4 dias; 0,1mg/kg por 3 dias; 0,1mg/kg por 3 dias e 0,25mg/kg por 3 dias. Entre o primeiro e o segundo período de administração e entre o segundo e o terceiro período os animais não receberam o MFA por 10 dias consecutivos; entre o terceiro e o quarto período e dentre os demais períodos de administração, os ovinos permaneceram 15 dias sem ingerir o MFA. Quinze dias após o último período de administração os ovinos foram desafiados com a dose única de 1mg/kg de MFA. O Grupo 2 não foi adaptado a ingestão de MFA, estes ovinos receberam dose única de 1mg/kg de MFA no mesmo período em que o G1 foi desafiado. No desafio sete ovinos do Grupo 1 apresentaram sinais clínicos da intoxicação e um ovino se recuperou. No Grupo 2 todos os animais manifestaram quadro clínico da intoxicação por MFA, no entanto, dois ovinos se recuperaram. Os coeficientes de mortalidade foram de 66,6% para o Grupo 1 e de 77,7% para o Grupo 2. Os resultados deste trabalho sugerem que a administração repetida de doses não tóxicas de MFA não protege contra a intoxicação aguda por este composto, portanto, outras alternativas para a profilaxia da intoxicação por plantas que contêm MFA deverão ser pesquisadas, principalmente a utilização intraruminal de bactérias que hidrolisam MFA.

With the objective to assess whether repeated non-toxic doses of sodium monofluoroacetate (MFA) induce resistance to poisoning by this compound, 18 sheep were randomly divided into two experimental groups of nine animals each. Sheep from Group 1 ingested non-lethal increasing doses of MFA for six periods: 0.05mg/kg for 5 days; 0.08mg/kg for 4 days; 0.08mg/kg for 4 days; 0.1mg/kg for 3 days; 0.1mg/kg for 3 days and 0.25mg/kg for 3 days. Between the first and second period of administration and between the second and third period the animals did not receive MFA for 10 consecutive days, between the third and fourth period and during the remaining periods of administration the sheep were left 15 days without ingesting MFA. Group 2 was not adapted to the ingestion of MFA and received a single dose of 1mg/kg of MFA at the same time that Group 1 was challenged. After challenge, seven sheep of Group 1 showed clinical signs of poisoning and one sheep recovered. In Group 2, all animals showed clinical signs of poisoning by MFA, however two sheep recovered. The mortality rate was 66.6% in Group 1 and 77.7% for Group 2. These results suggest that repeated administration of non-toxic doses of MFA does not protect against acute poisoning by this compound; therefore other alternatives of prophylaxis for poisoning by plants containing MFA should be searched, mainly the use of intraruminal bacteria that hydrolyze MFA.

1277 downloads

11.

Análise produtiva e econômica do pimentão-vermelho irrigado com diferentes lâminas, cultivado em ambiente protegido
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Carvalho, Jacinto de A.

; Rezende, Fátima C.

; Aquino, Reinaldo F.

; Freitas, Wellington A. de

; Oliveira, Eduardo C.

Revista Brasileira de Engenharia Agrícola e Ambiental

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jun 2011, Volume 15 N. 6 Pages 569 - 574

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

O manejo da irrigação é importante não apenas por suprir as necessidades hídricas das culturas mas, também, por minimizar os problemas de doenças, lixiviação de nutrientes e gastos com consumo de água e energia. Objetivou-se, com o presente trabalho, uma avaliação técnica e econômica da produção do pimentão-vermelho em função de lâminas de irrigação. O experimento foi instalado em ambiente protegido, com delineamento inteiramente casualizado (DIC), com cinco tratamentos de reposição de água no solo (50, 75, 100, 125 e 150%) e quatro repetições. Os resultados permitiram concluir que o número de frutos por planta, o peso médio dos frutos e, consequentemente, a produção por planta, foram afetados pelos níveis de reposição de água no solo. A máxima produtividade foi de 35.300 kg ha-1 com a aplicação de 443,9 mm e a lâmina ótima econômica foi estimada em 443,5 mm. Os maiores retornos econômicos são obtidos mantendo a cultura com umidade próxima da capacidade de campo, repondo integralmente a quantidade de água consumida. A maior eficiência no uso da água foi estimada em 74,76 kg ha-1 mm-1, com a aplicação de 334,1 mm.

The irrigation management is not only an important factor to supply plant's water needs, but also to minimize problems with diseases, nutrient leaching as well as unnecessary expenses with water and energy. This study had the aim to verify the economic feasibility of red bell pepper (Capsicum annuum, L.) yield under different irrigation depths, cultivated in greenhouse. A completely randomized design (CRD) was used, with five levels of replacement of irrigation water (50, 75, 100, 125 and 150%) with four replications. Significant differences were found for number of fruits per plant and total production of the plant. The maximum productivity obtained was equal to 35,300 kg ha-1 for a water depth of 443.9 mm and the optimum economic irrigation water depth was 443.5 mm; higher economic returns are obtained by keeping the crop with a water content near field capacity, restoring the full amount of water consumed. The highest water use efficiency was 74.76 kg ha 1 mm-1 for a water depth of 334.1 mm.

5510 downloads

12.

Effects of water deficit in two phenological stages on production of japanese cucumber cultived in greenhouse
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Oliveira, Eduardo C.

; Carvalho, Jacinto de A.

; Silva, Wellington G. da

; Rezende, Fátima C.

; Almeida, Willian F. de

Engenharia Agrícola

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2011, Volume 31 N. 4 Pages 676 - 686

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

O experimento foi realizado na área experimental do Departamento de Engenharia da Universidade Federal de Lavras, em Lavras - MG, e teve como objetivo identificar um manejo adequado da irrigação para a produção do pepino-japonês (Cucumis sativus L.) cultivado em ambiente protegido. Foi utilizado um delineamento inteiramente casualizado, envolvendo, como tratamentos, quatro níveis de potencial de água no solo (15; 30; 60 e 120 kPa) em duas fases fenológicas da cultura (vegetativa e reprodutiva), com 5 repetições. De forma geral, os resultados mostraram decréscimo da produtividade de acordo com o incremento do potencial de água no solo; as plantas do pepineiro-japonês, quando na fase reprodutiva, mostraram-se mais sensíveis ao déficit hídrico, redundando em maiores quedas de produtividade em comparação com o déficit hídrico aplicado durante a fase vegetativa da cultura.

The experiment was performed in the experimental area of the Engineering Department Federal University of Lavras, Minas Gerais State, Brazil. It aimed at identifying the adequate irrigation management of the greenhouse-cultivated Japanese cucumber (Cucumis sativus L.). complete randomized design, with four levels of soil water potential (15; 30; 60 e 120 kPa) at two phenological phases (vegetative and reproductive), and 5 replications. Overall, the results showed decrease of yield according to increase of soil water potentials. During the reproductive stage, Japanese cucumber plants were more sensitive to water deficit, resulting in further decrease in yield compared to applied water deficit during the vegetative stage of the culture.

3861 downloads

13.

Avaliação da microestrutura e das propriedades magnéticas de ferritas Ni-Zn dopadas com cobre
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Torquato, R. A.

; Portela, F. A.

; Gama, L.

; Cornejo, D. R.

; Rezende, S. M.

; Kiminami, R. H. G. A.

; Costa, A. C. F. M.

Cerâmica

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mar 2008, Volume 54 N. 329 Pages 55 - 62

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

A microestrutura e as propriedades magnéticas das ferritas Ni0,5-xCu xZn0,5Fe2O4 com x = 0,1/0,2/0,3/0,4 mol de cobre, preparadas a partir de pós obtidos por reação de combustão com tamanho de partícula na faixa de 23 a 29 nm, foram avaliadas. Os pós obtidos foram prensados uniaxialmente e sinterizadas a 1000 ºC/2 h. As amostras foram caracterizadas por medidas de densidade e porosidade aparente, difração de raios X, microscopia eletrônica de varredura e medidas magnéticas M-H. Os difratogramas de raios X mostram a presença da fase majoritária cristalina do espinélio inverso em todos os sistemas, e traços da fase secundária Fe2O3 nas amostras com x = 0,1 e 0,4. O aumento do teor de cobre causou um pequeno aumento no tamanho médio de grão (0,65 para 0,68 µm), uma redução da porosidade aparente (33,7% para 6,6%) e redução da magnetização de saturação de 69 para 54 emu/g.

An evaluation was made of the microstructure and magnetic properties of Ni0.5-xCu xZn0,5Fe2O4 ferrites with x = 0.1, 0.2, 0.3 and 0.4 prepared by combustion reaction with particle sizes 23 to 29 nm. The resulting powders were uniaxially compacted at 385 MPa into pellets and sintered at 1000 ºC/2 h. The samples were characterized by apparent density and porosity measurements, X-ray diffraction, scanning electron microscopy and M-H magnetic measurements. The X-ray diffraction revealed crystalline inverse spinel as the major phase in all the specimens and a small amount of hematite (a-Fe2O3) as the secondary phase in the x = 0.1 and 0.4 samples. An increase in the amount of copper caused a slight increase in grain size (0.65 to 0.68 µm), a decrease in the apparent porosity (33.7% to 6.6%) and a reduction in saturation magnetization from 69 to 54 emu/g.

3728 downloads Cited 2 times in SciELO

14.

Ácido 15-desmetilisoplumierídeo, um novo iridóide isolado das cascas de Plumeria rubra e do látex de Himatanthus sucuuba
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Barreto, Alaide de Sá

; Amaral, Ana Cláudia F.

; Silva, Jefferson Rocha de A.

; Schripsema, Jan

; Rezende, Cláudia M.

; Pinto, Angelo C.

Química Nova

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oct 2007, Volume 30 N. 5 Pages 1133 - 1135

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Himatanthus sucuuba and Plumeria rubra are used in folk medicine in Brazil to treat various ailments. The isolation of the new iridoid 15-demethylisoplumieride from the bark of Plumeria rubra L. var. acutifolia (Ait) Woodson and latex of Himatanthus sucuuba (Spruce) Woodson is reported. Other iridoid glycosides were obtained from both plants. The structures of these substances were elucidated by spectral analysis and comparison with data already reported.

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15.

Determinação da distribuição de funcionalidade de HTPB e verificação de sua influência no comportamento mecânico de poliuretano utilizado em motor-foguete
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Lourenço, Vera L.

; Kawamoto, Aparecida M.

; Sciamareli, Jairo

; Rezende, Luis C.

; Pires, Darci C.

; Takahashi, Marta F. K.

; Berdugo, Agda V.

; Cruz, Sandra M.

; Dutra, Rita C.L.

; Soares, Bluma G.

Polímeros

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mar 2006, Volume 16 N. 1 Pages 66 - 70

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Um método SEC com dupla detecção para determinação de distribuição de funcionalidade de resina polibutadiênica hidroxilada HTPB foi desenvolvido, verificando-se a influência desse parâmetro no comportamento mecânico de poliuretano utilizado em motor-foguete fabricado no Centro Técnico Aeroespacial (CTA). O método mostrou-se sensível a pequenas diferenças de funcionalidade e sua distribuição podendo ser utilizado para a caracterização mais completa da resina. Ensaios de tração realizados em amostras de PU sem carga refletiram pequenas diferenças de distribuição de funcionalidade existentes entre os lotes de polibutadieno hidroxilado.

A size exclusion chromatography (SEC) method, with double detection, was developed to determine the functionality distribution of hydroxyl polybutadiene (HTPB) resin, evaluating the influence of that parameter on the mechanical behavior of HTPB polyurethane used as binder in the rocket motors manufactured at Centro Técnico Aeroespacial (CTA). The method showed to be sensitive to small differences in the functionality distribution of the HTPB resin and, thus, can be used for a more complete characterization of the resin. Tensile tests performed on HTPB polyurethane reflected the small differences observed in the functionality distribution of three batches of HTPB.

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