ABSTRACT
This study was conducted to determine the incorporation of 15nitrogen (15N) into liver and kidney of a group of rats (N = 17) fed a mixture of cooked rice and beans for 4 weeks. The beans (Phaseolus vulgaris), grown in soil cultivated with (15NH4)2SO4, had 1.5% 15N enrichment. Three or four rats were sacrificed weekly and a control group (N = 13) received an isonitrogen and isocaloric reference casein diet. The amount of nitrogen transferred from the beans to the liver at the end of the first, second, third and fourth weeks was 17, 11, 27 and 29% of the total nitrogen, respectively. For the kidney, the respective values were 10, 9, 25 and 27% of the total nitrogen. The total nitrogen content of the liver and kidney of rats receiving the reference casein control diet was similar to that of the rice/beans animals. Weight gain was similar for the two groups, indicating the well-balanced biological value of the experimental diet. The present study shows that it is possible to monitor 15N incorporation into beans and subsequently into rat liver and kidney, in contrast to classical methods for protein metabolism evaluation which measure only total body nitrogen intake and excretion or weight gain.
Subject(s)
Diet , Fabaceae , Kidney/metabolism , Liver/metabolism , Nitrogen/metabolism , Oryza , Plants, Medicinal , Animals , Dietary Proteins/metabolism , Male , Nitrogen Isotopes , Nutritive Value , Rats , Rats, Inbred Strains , Weight GainABSTRACT
This study was conducted to determine the incorporation of 15 nitrogen (15N) into liver and kidney of a group of rats (N = 17) fed a mixture of cooked rice and beans for 4 weeks. The beans (Phaseolus vulgaris), grown in soil cultivated with (15NH4)2sO4, had 1.5% 15N enrichment. Three or four rats were sacrificed weekly and a control group (N = 13) received an isonitrogen and isocaloric reference casein diet. The amount of nitrogen transferred from the beans to the liver at the end of the first, second, third and fourth weeks was 17, 11, 27 and 29% of the total nitrogen, respectively. For the kidney, the respective values were 10, 9, 25 and 27% of the total nitrogen. The total nitrogen content of the liver and kidney of rats receiving the reference casein control diet was similar to that of the rice-beans animals. Weight gain was similar for the two groups, indicating the well-balanced biological value of the experimental diet. The present study shows that its is possible to monitor 15N incorporation into beans and subsequently into rat liver and kidney, in contrast to classical methods for protein metabolism evaluation which measure only total body nitrogen intake and excretion or weight gain
Subject(s)
Rats , Diet , Fabaceae , Liver/metabolism , Kidney/metabolism , Nitrogen/metabolism , Oryza , Nitrogen Isotopes , Nutritive Value , Dietary Proteins/metabolism , Rats, Wistar , Weight GainABSTRACT
SUMMARY In order to improve the understanding of the water in the Amazon Basin, samples of rain and moisture were collected daily at Belém and Manaus from August 78 to January 80. All isotope data are presented. The most depleted values, sometimes lower than 10 in 18O at Belém or Manaus, were encountered during the rainy season (January-April). Possible causes of the seasonal differences in tne isotope pattern are discussed.
Resumo No período de agosto de 1978 a janeiro de 1980, foram feitas coletas diárias de amostras de águas de chuva e de vapor d'água do ar em Belém e Manaus, a fim de ampliar os conhecimentos a cerca de parâmetros ligados ao ciclo da água na bacia Amazônica. Estão apresentados os dados isotópicos referentes as amostras. Os valores mais negativos ocorreram durante o período chuvoso (janeiro-abril), atingindo muitas vezes, valores de 18O menores do que 10. São discutidas as possíveis causas dessas composições.
ABSTRACT
SUMMARY In order to improve the understanding of the water in the Amazon Basin, samples of rain and moisture were collected daily at Belém and Manaus from August 78 to January 80. All isotope data are presented. The most depleted values, sometimes lower than 10 in 18O at Belém or Manaus, were encountered during the rainy season (January-April). Possible causes of the seasonal differences in tne isotope pattern are discussed.
Resumo No período de agosto de 1978 a janeiro de 1980, foram feitas coletas diárias de amostras de águas de chuva e de vapor d'água do ar em Belém e Manaus, a fim de ampliar os conhecimentos a cerca de parâmetros ligados ao ciclo da água na bacia Amazônica. Estão apresentados os dados isotópicos referentes as amostras. Os valores mais negativos ocorreram durante o período chuvoso (janeiro-abril), atingindo muitas vezes, valores de 18O menores do que 10. São discutidas as possíveis causas dessas composições.
ABSTRACT
Summary Isotopic concentration was detected in different spots of Rio Negro, Rio Solimões and Rio Amazonas at regular intervals, for 12 consecutive months. Values as found in Rio Negro waters were significantly different. Difference between isotopic concentration found in Rio Negro and Rio Solimões was considered as useful information for identifying the spot where Rio Amazonas, formed by the confluence of Negro and Solimões, presents a homogenous vertical and horizontal structure after complete mixing of both rivers. A perfect mixture was not found up to 120 km below the confluence. Systematic sampling was found to be a method for the determination of relative outflow of both rivers. Data as obtained are close to the results of direct measurements performed by Oltman et al (1963).
Sinopse Foram encontradas concentrações isotopicas diferentes nas águas do Rio Negro e do Rio Solimões. Partindo daquela verificação preliminar, foi feita a amostragem sistemática de águas daqueles dois rios e do rio Amazonas, procurando-se determinar abaixo da confluência dos mesmos, o local onde o rio Amazonas apresenta uma estrutura horizontal e vertical homogênea traduzindo perfeita mistura das águas dos rios formadores. Os dados obtidos permitem também o cálculo, com razoável precisão, da vasão relativa de ambos os rios para alguns meses. Verificou-se que a 120 Km da confluência do Negro e o Solimões, ainda não havia mistura perfeita e que abaixo daquele ponto, a confluência do Madeira introduz perturbações na mistura. O grau de mistura em diferentes pontos apresenta oscilações em amostras colhidas em diferentes meses. Os dados obtidos pela medida da concentração isotopica concordam sensivelmente com os resultados das medidas diretas efetuadas por Oltman et al (1963).
ABSTRACT
Summary Isotopic concentration was detected in different spots of Rio Negro, Rio Solimões and Rio Amazonas at regular intervals, for 12 consecutive months. Values as found in Rio Negro waters were significantly different. Difference between isotopic concentration found in Rio Negro and Rio Solimões was considered as useful information for identifying the spot where Rio Amazonas, formed by the confluence of Negro and Solimões, presents a homogenous vertical and horizontal structure after complete mixing of both rivers. A perfect mixture was not found up to 120 km below the confluence. Systematic sampling was found to be a method for the determination of relative outflow of both rivers. Data as obtained are close to the results of direct measurements performed by Oltman et al (1963).
Sinopse Foram encontradas concentrações isotopicas diferentes nas águas do Rio Negro e do Rio Solimões. Partindo daquela verificação preliminar, foi feita a amostragem sistemática de águas daqueles dois rios e do rio Amazonas, procurando-se determinar abaixo da confluência dos mesmos, o local onde o rio Amazonas apresenta uma estrutura horizontal e vertical homogênea traduzindo perfeita mistura das águas dos rios formadores. Os dados obtidos permitem também o cálculo, com razoável precisão, da vasão relativa de ambos os rios para alguns meses. Verificou-se que a 120 Km da confluência do Negro e o Solimões, ainda não havia mistura perfeita e que abaixo daquele ponto, a confluência do Madeira introduz perturbações na mistura. O grau de mistura em diferentes pontos apresenta oscilações em amostras colhidas em diferentes meses. Os dados obtidos pela medida da concentração isotopica concordam sensivelmente com os resultados das medidas diretas efetuadas por Oltman et al (1963).