Liver and kidney nitrogen uptake in rats fed beans enriched with 15 nitrogen through (15NH4)2SO4 used as soil fertilizer

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

Precipitation in the central amazon basin: - the isotopic composition of rain and atmospheric moisture at belém and manaus

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.