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Antioxidant activity and phenolic contents of Olea europaea L. leaves sprayed with different copper formulations

Ferreira, Isabel C.F.R.; Barros, Lillian; Soares, Maria Elisa; Bastos, Maria de Lourdes; Pereira, J.A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
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36.39%
Olive trees (Olea europaea L. Cv. Cobranc¸osa) from the northeast of Portugal were sprayed with three different copper formulations [bordeaux mixture (copper sulphate + calcium hydroxide - 20% Cu), copper hydroxide (40% Cu) and copper oxychloride (50% Cu)] to control olive fungal diseases. The residues of copper in olive leaves, harvested at different times, were evaluated by atomic absorption spectrometry. At all the collection times, treated olive leaves had significantly higher copper contents, compared to the control. The different copper amounts in pesticide formulations lowered the leaves contents in total phenols and hence their antioxidant properties. Olive leaves sprayed with copper oxychloride possessed the highest copper levels and the lowest content in phenols, which influenced its antioxidant activity (higher EC50 values for reducing power, scavenging effect on DPPH radicals and inhibition of erythrocyte hemolysis). Leaves without copper residues proved to be a good natural source of antioxidants, giving values comparable to the reference compounds.

Phenolic profile of Cydonia oblonga Miller leaves

Oliveira, Andreia P.; Pereira, J.A.; Andrade, P.B.; Valentão, P.; Seabra, R.M.; Silva, B.M.
Fonte: ACS Publicador: ACS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.42%
Cydonia oblonga Miller leaves phenolic compounds were analyzed by reversed-phase HPLC/DAD and HPLC/UV. Qualitative and quantitative analysis of phenolics were carried out in a total of 36 samples of quince leaves from three different geographical origins of Northern (Bragança and Carrazeda de Ansiães) and Central Portugal (Covilhã) and three collection months (June, August, and October of 2006). These leaves presented a common phenolic profile composed by nine compounds: 3-O-, 4-O- and 5-O-caffeoylquinic acids, 3,5-O-dicaffeoylquinic acid, quercetin-3-Ogalactoside, quercetin-3-O-rutinoside, kaempferol-3-O-glycoside, kaempferol-3-O-glucoside, and kaempferol-3-O-rutinoside. 5-O-caffeoylquinic acid was the major phenolic compound (36.2%), followed by quercetin 3-O-rutinoside (21.1%). Quince leaves are characterized by higher relative contents of kaempferol derivatives than fruits (pulps, peels, and seeds), especially in what concerns kaempferol-3-O-rutinoside (12.5%). C. oblonga leaves total phenolic content was very high, varying from 4.9 to 16.5 g/kg dry matter (mean value of 10.3 g/kg dry matter), indicating that these leaves can be used as a good and cheap source of bioactive constituents. Significantly differences were observed in 3-O-caffeoylquinic and 3...

Walnut (Juglans regia L.) leaves: phenolic compounds, antimicrobial activity ans antioxidant potential of different cultivars

Pereira, J.A.; Oliveira, Ivo; Sousa, A.; Valentão, P.; Andrade, P.B.; Ferreira, Isabel C.F.R.; Ferreres, F.; Bento, Albino; Seabra, R.M.; Estevinho, Leticia M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.36%
Different cultivars of walnut (Juglans regia L.) leaves (Cv. Lara, Franquette, Mayette, Marbot, Mellanaise and Parisienne) grown in Portugal, were investigated in what concerns phenolic compounds and antimicrobial and antioxidant properties. Phenolics analysis was performed by reversed-phase HPLC/DAD and 10 compounds were identified and quantified: 3- and 5-caffeoylquinic acids, 3- and 4-pcoumaroylquinic acids, p-coumaric acid, quercetin 3-galactoside, quercetin 3-pentoside derivative, quercetin 3-arabinoside, quercetin 3-xyloside and quercetin 3-rhamnoside. The antimicrobial capacity was screened against Gram positive (Bacillus cereus, B. subtilis, Staphylococcus aureus) and Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae) and fungi (Candida albicans, Cryptococcus neoformans). Walnut leaves selectively inhibited the growth of Gram positive bacteria, being B. cereus the most susceptible one (MIC 0.1 mg/mL). Gram negative bacteria and fungi were resistant to the extracts at 100 mg/mL. Lara walnut leaves were also submitted to antibacterial assays using 18 clinical isolates of Staphylococcus sp. Antioxidant activity was accessed by the reducing power assay, the scavenging effect on DPPH (2...

Scavenging capacity of strawberry tree (Arbutus unedo L.) leaves on free radicals

Oliveira, Ivo; Coelho, Valentim; Baltasar, R.; Pereira, J.A.; Baptista, Paula
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.36%
Despite strawberry tree (Arbutus unedo L.) leaves had a long use in traditional medicine due to its antiseptic, diuretic, astringent and depurative properties, the potential of their antioxidant activity are still lacking. Our study goals to assess the antioxidant and free radical scavenging potential of water, ethanol, methanol and diethyl ether extracts of A. unedo leaves. Total phenols content was achieved spectrophotometrically using Folin–Ciocalteau reagent with gallic acid as standard. Antioxidant activity was evaluated using three different methods: reducing power of iron (III)/ferricyanide complex assay, scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and scavenging effect on superoxide radicals by using the PMS–NADH–nitroblue tetrazolium system. Ethanol extracts of A. unedo leaves were the highest in reducing power (IC50 232.7 lg/mL) and DPPH scavenging effect (IC50 63.2 lg/mL) followed by water extracts (with IC50 of 287.7 and 73.7 lg/mL, respectively); whereas diethyl ether extracts were the lowest. In the scavenging on superoxide radical assay, methanol extracts obtained the best results (IC50 6.9 lg/mL). For all the methods tested the antioxidant activity was concentration dependent. In accordance with antioxidant activity...

Total phenol concentrations in coffee tree leaves during fruit development; Concentrações de fenóis totais nas folhas do cafeeiro durante desenvolvimento dos frutos

SALGADO, Paula Rodrigues; FAVARIN, José Laércio; LEANDRO, Roseli Aparecida; LIMA FILHO, Oscar Fontão de
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.42%
Vegetables have a natural defense against external factors synthesizing phenolic compounds, which depends on the maturity stage and on the climate. Total phenol grades were extracted from mature and young coffee leaves and were analyzed in relation to yield, phenology and climate. The climatic conditions were described by air temperature, global radiation and daily insolation. Evaluations were made on height, diameter and length of reproductive branches to determine the respective vegetative growth rates of the plants. The amounts of total phenols in the plants at the production stage was 174.0 mg g-1 and 138.9 mg g-1 for young and mature leaves, respectively, and for plants without fruit formation 186.5 mg g-1 and 127.6 mg g-1 for young and mature leaves, respectively. The total phenol concentrations in young leaves with and without fruit formation were 25% and 46% greater compared to mature leaves. The secondary phenol synthesis in seed (146.8 mg g-1) was 31% lower than during grain maturation (212.4 mg g-1). The total phenol metabolization depends indirectly on the temperature and on the global radiation, presenting an inverse trend in relation to these climatic variables. Crop protection management should take into consideration periods of endanger of this natural defense of the plant.; Os vegetais apresentam defesa natural contra fatores externos...

Effect of eucalyptus (Eucalyptus citriodora) fresh or residue leaves on methane emission in vitro

SALLAM, Sobhy M. A.; BUENO, Ives C. S.; NASSER, Mohamed E. A.; ABDALLA, Adibe L.
Fonte: PAGEPRESS PUBL Publicador: PAGEPRESS PUBL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.39%
Rumen fermentation and methane emission for eucalyptus (Eucalyptus citriodora) fresh leaves (FL) or residue leaves (RL), after essential oil extraction from eucalyptus leaves in comparison with alfalfa (Medicago sativa) hay, were investigated in vitro. Eucalyptus FL and RL were obtained from the Distillery Trees Barras Company, Torrinha City, Sao Paulo, Brazil. The semi-automatic system of gas production was used to measure gas production, methane emission and rumen fermentation after 24 h incubation in vitro. The results showed that the crude protein (CP) contents were 76.4, 78.1 and 181.9 g kg(-1) DM for eucalyptus FL, RL and alfalfa hay, respectively. The neutral-detergent fibre (NDF) and acid-detergent fibre (ADF) were significantly lower in eucalyptus FL and RL than alfalfa hay. The Eucalyptus fresh and residue leaves were rich in total phenols (TP) and total tannins (TT) but had negligible content of condensed tannins (CT). There was significant reduction in cumulative gas production about 54 and 51% with eucalyptus FL and RL, respectively, compared with alfalfa hay. The methane emission (mL/g DM) was reduced (P<0.05) by 53 and 57% with eucalyptus FL and RL, respectively, but the reduction was 21 and 16% when expressed on truly digested organic matter basis. There were a decline (P<0.05) in true dry and organic matter degradation in vitro in eucalyptus FL and RL compared with alfalfa hay substrate. The partitioning factor values were higher (P<0.05) in eucalyptus FL and RL than alfalfa hay. There was no significant difference observed between eucalyptus FL...

Extração do óleo essencial e oleoresina das folhas de Corymbia citriodora utilizando CO2 em condições sub e supercríticas; Extraction of essential oil and oleoresin from Corymbia citriodora leaves using near and supercritical CO2

Dogenski, Mirelle
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/10/2013 PT
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36.36%
Este trabalho teve como objetivo o mapeamento da composição do óleo essencial (OE) de Corymbia citriodora produzido no Brasil pelas principais destilarias, Três Barras (FTB) e Meneghetti (FMG), e a extração do OE e oleoresina (OR) a partir das folhas utilizando a tecnologia de fluidos supercríticos. Foram estudados os efeitos das condições do processo, pressão (P) e temperatura (T), sobre a composição química e rendimento dos extratos, além da atividade antioxidante de alguns ensaios. As folhas picotadas apresentaram umidade de 7,33±1,1 e 8,66±0,5% para a FMG e FTB, respectivamente. As extrações, a partir das folhas com CO2 em condições sub e supercríticas, foram realizadas em duas etapas. Na primeira etapa, obteve-se o OE e, em seguida, as condições foram reajustadas para se fazer a extração da OR. As combinações das variáveis P e T foram determinadas conforme um delineamento composto central rotacional (DCCR), sendo feito um para cada etapa de extração. Para todos os extratos obtidos na primeira etapa, bem como dos OEs obtidos por arraste à vapor (AV) e hidrodestilação (HD), determinou-se o perfil de voláteis por cromatografia gasosa acoplado ao espectrofotômetro de massa (GC/MS). Os ensaios de maior rendimento em OE sem a coextração de pigmentos (100 bar e 60ºC...

Estudo de diferentes metodologias para a obtenção de extratos de folhas de oliveira (Olea europaea) contendo oleuropeína; Study of different methodologies for obtaining extracts from olive leaves (Olea europaea) containing oleuropein

Pacetta, Cosmo Fernando
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/12/2013 PT
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36.39%
A oleuropeína é o mais abundante biofenol presente nas folhas de oliveira (Olea Europaea), com importantes funções antimicrobiana e antioxidante. Estudos visando à obtenção deste composto têm sido conduzidos, porém, muitos deles utilizam solventes tóxicos e métodos caros. A presente dissertação teve por objetivo estudar diferentes metodologias para a obtenção de extratos de folhas de oliva contendo quantidades significativas de oleuropeína. Os extratos foram obtidos a partir de folhas de oliva micronizadas, com ou sem pré-tratamento para redução do teor de clorofila, submetidas a contatos simples ou múltiplos com diferentes solventes, como dietil éter, clorofórmio, acetona, etanol, 1-propanol, 2-propanol, água e soluções hidroalcoólicas com diferentes concentrações. O contato das folhas micronizadas com os solventes foi promovido pelos seguintes métodos: agitação manual em temperatura ambiente, agitação mecânica a 50 ºC, ultrassom ou uma combinação desses dois últimos, totalizando 38 experimentos, sendo que em 17 destes os extratos foram produzidos na forma líquida e 21 na forma sólida. Os resultados mostraram que, de maneira geral, a etapa prévia de redução do teor da clorofila (realizada através de sucessivos contatos com hexano...

Genotoxicity of Nicotiana tabacum leaves on Helix aspersa

Silva, Fernanda Rabaioli da; Erdtmann, Bernardo; Dalpiaz, Tiago; Nunes, Emilene; Ferraz, Alexandre; Martins, Tales L. C.; Dias, Johnny Ferraz; Rosa, Darlan Pase da; Porawski, Marilene; Bona, Silvia Regina; Silva, Juliana da
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
36.46%
Tobacco farmers are routinely exposed to complex mixtures of inorganic and organic chemicals present in tobacco leaves. In this study, we examined the genotoxicity of tobacco leaves in the snail Helix aspersa as a measure of the risk to human health. DNA damage was evaluated using the micronucleus test and the Comet assay and the concentration of cytochrome P450 enzymes was estimated. Two groups of snails were studied: one fed on tobacco leaves and one fed on lettuce (Lactuca sativa L) leaves (control group). All of the snails received leaves (tobacco and lettuce leaves were the only food provided) and water ad libitum. Hemolymph cells were collected after 0, 24, 48 and 72 h. The Comet assay and micronucleus test showed that exposure to tobacco leaves for different periods of time caused significant DNA damage. Inhibition of cytochrome P450 enzymes occurred only in the tobacco group. Chemical analysis indicated the presence of the alkaloid nicotine, coumarins, saponins, flavonoids and various metals. These results show that tobacco leaves are genotoxic in H. aspersa and inhibit cytochrome P450 activity, probably through the action of the complex chemical mixture present in the plant.

The effect of olive leaves supplementation on the feed digestibility, growth performances of pigs and quality of pork meat

Paiva-Martins, F.; Barbosa, S; Pinheiro, Victor; Mourão, José Luís; Outor-Monteiro, Divanildo
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.39%
The influence of olive leaves supplementation on feed digestibility, growth performance of pigs and pork meat quality was investigated. Pigs fed diets with olive leaves at 5% (OL5) and 10% (OL10) levels had lower daily weight gain (DG) and daily feed intake (DFI) than pigs fed a conventional diet (OL0) but differences were not observed between groups fed with the different quantities of leaves. Additionally, pigs fed diets with leaves had the worst feed:gain ratio and showed a decrease in overall backfat. Chops from pigs fed the leaf diets had lower peroxide (PV) and conjugated diene (CD) contents than chops from pigs fed conventional diets. Moreover, chops from pigs fed with the higher quantity of leaves also showed a lower drip loss. After a storage period of 8 days at 4°C, meat obtained from both OL5 and OL10 animals also differed (P<0.05) in PV and %CD values from those fed a conventional diet. Since the fatty acid composition of the longissimus muscles was not different, differences in oxidative stability could only be explained by the significantly higher α-tocopherol concentration in intramuscular fat and backfat in pigs fed with olive leaf diets.

Temperature-dependent alterations of respiration in leaves of two selected vascular plant species: the role of the alternative oxidase pathway

Pystina,Natalia V.; Danilov,Roman A.
Fonte: Instituto Agronômico de Campinas Publicador: Instituto Agronômico de Campinas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2002 EN
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36.36%
Effects of higher temperatures on respiration and activity of alternative oxidase (AOX) were studied in mature leaves of Ajuga reptans L. and Rhodiola rosea L. Total respiration in both A. reptans and R. rosea increased exponentially with the increasing temperature of 10 °C to 35 °C. Respiration in the presence of benzhydroxamic acid (BHAM) also increased exponentially in accordance with the increasing temperature in the leaves of both A. reptans and R. rosea. Relative activity of the alternative pathway decreased significantly in the leaves of A. reptans with increasing temperatures. However, an increase in the relative activity of the alternative pathway was detected in the leaves of R. rosea. Thermoresistance of the alternative respiratory pathway was considered to be higher in R. rosea compared to A. reptans. We suppose that A. reptans and R. rosea have different mechanisms regulating partitioning of electrons to the alternative respiratory pathway.

Evaluation of beetroot (Beta vulgaris L.) leaves during its developmental stages: a chemical composition study

Biondo,Polyana Batoqui França; Boeing,Joana Schuelter; Barizão,Érica Oliveira; Souza,Nilson Evelazio de; Matsushita,Makoto; Oliveira,Claudio Celestino de; Boroski,Marcela; Visentainer,Jesuí Vergílio
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 EN
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36.44%
Beetroot leaves (Beta vulgaris L.) are commonly cut off and discarded before using its bulb due to lack of knowledge of how to use them. Aiming at using these leaves, in the present study, in natura and dehydrated beetroot leaves were chemically characterized in terms of fatty acid composition, proximate composition, minerals, total phenolic compounds (TPC), and antioxidant activity by DPPH• in different stages (60, 80, and 100 days) of development. The beetroot leaves showed significant levels of protein and lipids in all developmental stages, and all proximate composition nutrients decreased during these maturation stages; the highest content was observed at 60 days. The Fe content decreased during the developmental stages (from 342.75 to 246.30 mg.kg-1), while the content of K increased (from 13,367.64 to 20,784.90 mg.kg-1). With regard to to fatty acid composition, linolenic acid was present in the greatest quantity, and it increase up to 2.58 mg.g-1 (in natura) and 40.11 mg.g-1 (dehydrated) at 100 days of development. The n-6/n-3 ratios were low in all stages. The TPC and antioxidant activity by DPPH• changed during the developmental stages. The TPC was highest in the 100-day dehydrated leaves (15.27±0.12 mg GAE.g-1 FW), and the 50% inhibition of DPPH• (IC50 89.52 µg.mL-1) were better in the 60-day in natura leaves. This study shows that all developmental stages produced satisfactory results...

Influence of light regimes on respiration, activity of alternative respiratory pathway and carbohydrates content in mature leaves of Ajuga reptans L.

PYSTINA,NATALIA V.; DANILOV,ROMAN A.
Fonte: Sociedade Brasileira de Fisiologia Vegetal Publicador: Sociedade Brasileira de Fisiologia Vegetal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2001 EN
Relevância na Pesquisa
36.49%
Influence of different light regimes (plants grown in shade and in the sun) on respiration, activity of alternative respiratory pathway and carbohydrates content in mature leaves of Ajuga reptans L. was investigated. All experiments were carried out under natural conditions. Sun plants had higher respiration, activity of the alternative pathway and carbohydrates content compared to the shade plants. Additional experiments were performed in order to study effects of darkening as well as evolution of respiration and carbohydrates concentrations in leaves of A. reptans during the day. Darkening led to a decline in total respiration in all types of plants investigated. Activity of the alternative pathway remained unchanged by 20 % in the leaves of the shade plants. On the other hand, darkness led to a twofold decrease in the activity of the alternative pathway in the leaves of the sun plants. Content of soluble carbohydrates in the darkness did not change in the leaves of the shade plants while significantly decreased in the leaves of the sun plants. Total respiration in the mature leaves of the shade plants studied did not change significantly during the day. However, a significant increase in the total respiration was detected in the mature leaves of the sun plants in the evening and in the night. Activity of the alternative respiratory pathway did not change significantly in the leaves of the shade plants during the day and corresponds to ca 20 % of the total respiration. The sun plants examined exhibited significantly higher activity of the alternative pathway during the period of active photosynthesis. In general...

Spectroscopic and chromatographic fingerprint analysis of composition variations in Coffea arabica leaves subject to different light conditions and plant phenophases

Delaroza,Fernanda; Rakocevic,Miroslava; Malta,Galileu Bernardes; Bruns,Roy Edward; Scarminio,Ieda Spacino
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2014 EN
Relevância na Pesquisa
36.42%
Fingerprints of self-shaded and sunlight-exposed leaves of the same Coffea arabica plant were obtained to determine metabolic concentration changes owing to different light environments and phenological stages. Leaf extract yields of the ethanol, acetone, dichloromethane and hexane solvents, as well as their statistical design mixtures, are reported. Highest yields are obtained with binary 1:1 ethanol-acetone mixtures for all sun-exposed and self-shaded leaves. Principal component analysis (PCA) of Fourier transform infrared (FTIR) spectra of leaf extracts indicate spectral differences between 2962-2828, 1759-1543 and below 1543 cm-1 that can be attributed to higher concentrations of fatty acid esters or the ester group in triglycerides, caffeine, chlorogenic acids and carbohydrates that are more prevalent in leaves of flowering plants. High-performance liquid chromatography with UV diode array detector (HPLC-UV-DAD) spectra of the chromatographic peaks for the extracts showed that sun-exposed samples contain stronger absorptions for caffeine, chlorogenic acid and theobromine. Confirmatory experiments carried out with reference UV calibration curves determined caffeine contents for sun-exposed leaves that are about double those for self-shaded leaves of flowering plants. Knowledge of leaf caffeine content in Coffea arabica is of ecological importance since sun-exposed conditions seem more stressful than self-shading ones for this species. Lipid concentrations in self-shaded leaves are almost double those that were sun-exposed.

Total phenol concentrations in coffee tree leaves during fruit development

Salgado,Paula Rodrigues; Favarin,José Laércio; Leandro,Roseli Aparecida; Lima Filho,Oscar Fontão de
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
36.42%
Vegetables have a natural defense against external factors synthesizing phenolic compounds, which depends on the maturity stage and on the climate. Total phenol grades were extracted from mature and young coffee leaves and were analyzed in relation to yield, phenology and climate. The climatic conditions were described by air temperature, global radiation and daily insolation. Evaluations were made on height, diameter and length of reproductive branches to determine the respective vegetative growth rates of the plants. The amounts of total phenols in the plants at the production stage was 174.0 mg g-1 and 138.9 mg g-1 for young and mature leaves, respectively, and for plants without fruit formation 186.5 mg g-1 and 127.6 mg g-1 for young and mature leaves, respectively. The total phenol concentrations in young leaves with and without fruit formation were 25% and 46% greater compared to mature leaves. The secondary phenol synthesis in seed (146.8 mg g-1) was 31% lower than during grain maturation (212.4 mg g-1). The total phenol metabolization depends indirectly on the temperature and on the global radiation, presenting an inverse trend in relation to these climatic variables. Crop protection management should take into consideration periods of endanger of this natural defense of the plant.

Genotoxicity of Nicotiana tabacum leaves on Helix aspersa

Silva,Fernanda R. da; Erdtmann,Bernardo; Dalpiaz,Tiago; Nunes,Emilene; Ferraz,Alexandre; Martins,Tales L.C.; Dias,Johny F.; Rosa,Darlan P. da; Porawskie,Marilene; Bona,Silvia; Silva,Juliana da
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 EN
Relevância na Pesquisa
36.46%
Tobacco farmers are routinely exposed to complex mixtures of inorganic and organic chemicals present in tobacco leaves. In this study, we examined the genotoxicity of tobacco leaves in the snail Helix aspersa as a measure of the risk to human health. DNA damage was evaluated using the micronucleus test and the Comet assay and the concentration of cytochrome P450 enzymes was estimated. Two groups of snails were studied: one fed on tobacco leaves and one fed on lettuce (Lactuca sativa L) leaves (control group). All of the snails received leaves (tobacco and lettuce leaves were the only food provided) and water ad libitum. Hemolymph cells were collected after 0, 24, 48 and 72 h. The Comet assay and micronucleus test showed that exposure to tobacco leaves for different periods of time caused significant DNA damage. Inhibition of cytochrome P450 enzymes occurred only in the tobacco group. Chemical analysis indicated the presence of the alkaloid nicotine, coumarins, saponins, flavonoids and various metals. These results show that tobacco leaves are genotoxic in H. aspersa and inhibit cytochrome P450 activity, probably through the action of the complex chemical mixture present in the plant.

Physiological aspects of sun and shade leaves of Lithraea molleoides (Vell.) Engl. (Anacardiaceae)

Dias,Jaqueline; Pimenta,José Antonio; Medri,Moacyr Eurípedes; Boeger,Maria Regina Torres; Freitas,Claudinei Toledo de
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 EN
Relevância na Pesquisa
36.47%
The aim of this work was to compare the physiological parameters of sun and shade leaves of a specimen of L. molleoides. The higher-positional leaves, classified as sun leaves, presented similar photosynthetic rate, lower chlorophyill contents (a, b and total), same a chlorophyll /b chlrorophyll rate, lower transpiratory rate, same stomatal conductance and intercellular concentration of CO2 as the lower-positional leaves, classified as shade leaves. Nutrient concentration, except for Ca and Mg, was the same for both sun and shade leaves.The physiological parameter responses indicated that although receiving lower light intensity, the shade leaves had the same capacity to grow and develop as the sun leaves.

Re-creating Walt Whitman's Leaves of Grass into portuguese

Saraiva Junior, Gentil
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
ENG
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36.39%
Este trabalho está focalizado na tradução criativa da poesia de Walt Whitman para o português. O termo utilizado para nos referir a este processo é recriação, ou seja, uma tradução que vai além da tradução literal (que privilegia apenas os significados), buscando um trabalho de reconstrução conjunta de significados e significantes, dada a relação profunda existente entre ambos (o capítulo 3 trata desse método de tradução criativa, aqui indicado, além de abordar temas relacionados a este na poesia, como verso livre, ritmo, metro, etc.). Esse termo foi emprestado de meus mestres neste tipo de tradução, que são os poetas Concretistas brasileiros: Haroldo de Campos, Augusto de Campos e Décio Pignatari. Em inglês, utilizamos essa palavra com hífen, “re-creation” (e seus derivados), devido ao fato de que “recreation” indica apenas recreação, divertimento, e não um “criar de novo”. É preciso lembrar que o precursor neste campo tradutório, da tradução a qual também é criação, foi Ezra Pound, que nos trouxe a idéia de renovação constante da poesia via tradução, e recebe atenção mais aprofundada nas seções 3.2 e 3.3. Há outras traduções da obra de Whitman em português, inclusive uma edição completa de Folhas de Relva pela Martin Claret (2005)...

Mechanical defenses in leaves eaten by Costa Rican howling monkeys (Alouatta palliata).

Teaford, MF; Lucas, PW; Ungar, PS; Glander, KE
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Artigo de Revista Científica Formato: 99 - 104
ENG
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Primate species often eat foods of different physical properties. This may have implications for tooth structure and wear in those species. The purpose of this study was to examine the mechanical defenses of leaves eaten by Alouatta palliata from different social groups at Hacienda La Pacifica in Costa Rica. Leaves were sampled from the home-ranges of groups living in different microhabitats. Specimens were collected during the wet and dry seasons from the same tree, same plant part, and same degree of development as those eaten by the monkeys. The toughness of over 300 leaves was estimated using a scissors test on a Darvell mechanical tester. Toughness values were compared between social groups, seasons, and locations on the leaves using ANOVA. Representative samples of leaves were also sun-dried for subsequent scanning electron microscopy and energy dispersive x-ray (EDX) analyses in an attempt to locate silica on the leaves. Both forms of mechanical defense (toughness and silica) were found to be at work in the plants at La Pacifica. Fracture toughness varied significantly by location within single leaves, indicating that measures of fracture toughness must be standardized by location on food items. Monkeys made some food choices based on fracture toughness by avoiding the toughest parts of leaves and consuming the least tough portions. Intergroup and seasonal differences in the toughness of foods suggest that subtle differences in resource availability can have a significant impact on diet and feeding in Alouatta palliata. Intergroup differences in the incidence of silica on leaves raise the possibility of matching differences in the rates and patterns of tooth wear.

Concentrações de fenóis totais nas folhas do cafeeiro durante desenvolvimento dos frutos; Total phenol concentrations in coffee tree leaves during fruit development

Salgado, Paula Rodrigues; Favarin, José Laércio; Leandro, Roseli Aparecida; Lima Filho, Oscar Fontão de
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/01/2008 ENG
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Vegetables have a natural defense against external factors synthesizing phenolic compounds, which depends on the maturity stage and on the climate. Total phenol grades were extracted from mature and young coffee leaves and were analyzed in relation to yield, phenology and climate. The climatic conditions were described by air temperature, global radiation and daily insolation. Evaluations were made on height, diameter and length of reproductive branches to determine the respective vegetative growth rates of the plants. The amounts of total phenols in the plants at the production stage was 174.0 mg g-1 and 138.9 mg g-1 for young and mature leaves, respectively, and for plants without fruit formation 186.5 mg g-1 and 127.6 mg g-1 for young and mature leaves, respectively. The total phenol concentrations in young leaves with and without fruit formation were 25% and 46% greater compared to mature leaves. The secondary phenol synthesis in seed (146.8 mg g-1) was 31% lower than during grain maturation (212.4 mg g-1). The total phenol metabolization depends indirectly on the temperature and on the global radiation, presenting an inverse trend in relation to these climatic variables. Crop protection management should take into consideration periods of endanger of this natural defense of the plant.; Os vegetais apresentam defesa natural contra fatores externos...