Glycine metabolism by plant roots and its occurrence in Australian plant communities

Soluble organic nitrogen, including protein and amino acids, was found to be a ubiquitous form of soil N in diverse Australian environments. Fine roots of species representative of these environments were found to be active in the metabolism of glycine. The ability to incorporate [N-15]glycine was widespread among plant species from subantarctic to tropical communities. In species from subantarctic herbfield, subtropical coral cay, subtropical rainforest and wet heathland, [N-15]glycine incorporation ranged from 26 to 45% of (NH4+)-N-15 incorporation and was 2- to 3-fold greater than (NO3-)-N-15 incorporation. Most semiarid mulga and tropical savanna woodland species incorporated [N-15]glycine and (NO3-)-N-15 in similar amounts, 18-26% of (NH4+)-N-15 incorporation. We conclude that the potential to utilise amino acids as N sources is of widespread occurrence in plant communities and is not restricted to those from low temperature regimes or where N mineralisation is limited. Seedlings of Hakea (Proteaceae) were shown to metabolise glycine, with a rapid transfer of N-15 from glycine to serine and other amino compounds. The ability to take up and metabolise glycine was unaffected by the presence of equimolar concentrations of NO3- and NH4+. Isonicotinic acid hydrazide (INH) did not inhibit the transfer of N-15-label from glycine to serine indicating that serine hydroxymethyltransferase was not active in glycine catabolism. In contrast aminooxyacetate (AOA) strongly inhibited transfer of N-15 from glycine to serine and labelling of other amino compounds, suggesting that glycine is metabolised in roots and cluster roots of Hakea via an aminotransferase.

Protein-energy status and 15N-glycine kinetic study of child a cirrhotic patients fed low- to high-protein energy diets

In five male cirrhotic patients (Child A) and in four age- and sex-matched healthy control subjects, whole-body protein turnover was measured using a single oral dose of N-15-glycine as a tracer and urinary ammonia as end product. Subjects were studied in the fasting and feeding state, with different levels of protein and energy intake. The patients were underweight and presented lower plasma transthyretin and retinol-binding protein levels. When compared with controls, the kinetic studies showed patients to be hypometabolic in the fasting (Do) state and with the control diet [D-1 = (0.85 g of protein/154 kJ). kg(-1). day(-1)]. However, when corrected by body weight, the kinetic differences between groups disappeared, whereas the N-retention in the feeding state showed better results for the patients due mainly to their efficient breakdown decrease. When fed high-level protein or energy diets [D-2 = (0.9 g protein/195 kJ) and D-3 = (1.56 g protein/158 kJ). kg(-1). day(-1)], the patients showed D-0 = D-1 = D-2 < D-3 for N-flux and (D-0 = D-1) < D-3 (D-2 is intermediary) for protein synthesis. Thus, the present data suggest that the remaining mass of the undernourished mild cirrhotic patients has fairly good protein synthesis activity and also that protein, rather than energy intake, would be the limiting factor for increasing their whole-body protein synthesis.

Efeito da oferta dietética de proteína sobre o ganho muscular, balanço nitrogenado e cinética da 15N-glicina de atletas em treinamento de musculação

The effect of increased protein intake on the muscle mass gain, nitrogen balance and N-15-glycine kinetics was studied in six young, healthy subjects practitioners of strength training (> 2 years), without use of anabolic steroids and in agreement with the ethical principles of the research. All athletes received adequate diet (0.88g protein/kg/day) during 2 weeks prior the study (D1), and thereafter with diet providing 1.5g of protein/kg/day and 30kcal/g of protein (D2 diet) for the subsequent 2 weeks. Later on, they all received diet with 2.5g of protein/kg/day (D3 diet) and 30 kcal/g protein for the last two weeks. Body composition, food intake, blood biochemistry, nitrogen balance (NB) and 15N-glycine kinetics were determined at the beginning, after D1 (M0) and in the last days of the D2 (M1) and D3 (M2). The results showed at the end of the study (4 weeks) significant increase in muscle mass (1.63 +/- 0.9kg), without difference between D2 and D3. The NB followed the protein/energy consumption (M0 = -7.8g/day; M1 = 5.6g/day and D3 = 16.6g/day), the protein synthesis followed the NB, with M0 < (M1= M2) (M1 = 49.8 +/- 12.2g N/day and M2 = 52.5 +/- 14.0g N/day). Protein catabolism rate was similarly kept among diets. Thus, the results of the NB and N-15-glycine kinetics indicate that the recommended protein intake for these athletes is higher than the one for sedentary adults (0.88g/kg) and lower than 2.5g/kg, around 1.5g of protein/kg/day, with adjustment of the energy consumption to 30 kcal/g of protein.

Comparison of omega-3 fatty acids and sulfasalazine in ulcerative colitis

Fish oil omega-3 fatty acids exert antiinflammatory effects on patients with ulcerative colitis. However, a comparative study in patients with mild to moderate ulcerative colitis receiving only sulfasalazine or omega-3 fatty acids has not been performed. We sought to detect changes in the inflammatory disease activity with the use of either fish oil omega-3 fatty acids or sulfasalazine in patients with ulcerative colitis. Ten patients (five male, five female; mean age = 48 +/- 12 y) with mild to moderate active ulcerative colitis were investigated in a randomized cross-over design. They received either sulfasalazine (2 g/d) or omega-3 fatty acids (5.4 g/d) for 2 mo. Disease activity was assessed by clinical and laboratory indicators, sigmoidoscopy, histology, and whole-body protein turnover (with N-15-glycine). Treatment with w-3 fatty acids resulted in greater disease activity as detected by a significant increase in platelet count, erythrocyte sedimentation rate, C-reactive protein, and total fecal nitrogen excretion. No major changes in protein synthesis and breakdown were observed during either treatment. In conclusion, treatment with sulfasalazine is superior to treatment with omega-3 fatty acids in patients with mild to moderate active ulcerative colitis. Nutrition 2000;16:87-901 (C) Elsevier B.V. 2000.

Whole-body protein turnover in malnourished patients with child class B and C cirrhosis on diets low to high in protein energy

The purpose of this study was to determine the rate of whole-body protein turnover in moderately and severely alcoholic, malnourished, cirrhotic patients fed with different amounts of protein or energy. Six male patients (Child classes B and C) and four age- and sex-matched healthy control subjects were studied for 18 d in fasting and feeding states; a single oral dose of [N-15]glycine was used as a tracer and urinary ammonia was the end product. The kinetic study showed that patients had higher protein catabolism while fasting (patients: 3.14 +/- 1.2 g of lean body mass/9 h; controls: 1.8 +/- 0.3 g of lean body mass/9 h: P<0.02). Although not statistically significant, protein catabolism (grams of lean body mass/9 h) was lower with the hyperproreic/hyperenergetic diet when compared with fasting. Nitrogen retention was consistent with the lower protein-catabolism rate; a statistically significant increase in nitrogen balance was observed when patients were fed with the hyperproteic/hyperenergetic diet compared with fasting 14.3 +/- 3.2 g of nitrogen/d and -2.2 +/- 1.9 g of nitrogen/d, respectively; P < 0.01). These data indicate that Child class B and C cirrhotic patients are hypercatabolic and that Long-term nutritional intervention with a hyperproteic/hyperenergetic diet is likely needed to improve their clinical and nutritional status. Nutrition 2001;17:239-242. (C) Elsevier B.V. 2001.

Partial molar volumes of glycine and dl-alanine in aqueous ammonium sulfate solutions at 278.15, 288.15, 298.15 and 308.15 K

In this work, the partial molar volumes of glycine and DL-alanine in aqueous solutions of ammonium sulfate at 0.0, 0.1, 0.3, 0.7, and 1.0 mol.kg(-1) are determined between 278.15 and 308.15 K. Transfer volumes were obtained, which are larger for glycine than DL-alanine. On the contrary, the hydration numbers are higher for DL-alanine than glycine, and dehydration of the amino acids is observed with increasing temperature or salt molality. The data suggest that interactions between ion and charged/hydrophilic groups are predominant and, by applying the methodology proposed by Friedman and Krishnan, it was concluded that they are mainly pairwise. A group-contribution scheme has been successfully applied to the pairwise volumetric interaction coefficient. Finally, the dehydration effect on glycine, alanine and serine in the presence of different electrolytes has been rationalized in terms of the charge density and a parameter accounting for the cation's hydration.

Utilization Of (15)no3 (-) By Nodulated Soybean Plants Under Conditions Of Root Hypoxia.

Waterlogging of soils is common in nature. The low availability of oxygen under these conditions leads to hypoxia of the root system impairing the development and productivity of the plant. The presence of nitrate under flooding conditions is regarded as being beneficial towards tolerance to this stress. However, it is not known how nodulated soybean plants, cultivated in the absence of nitrate and therefore not metabolically adapted to this compound, would respond to nitrate under root hypoxia in comparison with non-nodulated plants grown on nitrate. A study was conducted with (15)N labelled nitrate supplied on waterlogging for a period of 48 h using both nodulated and non-nodulated plants of different physiological ages. Enrichment of N was found in roots and leaves with incorporation of the isotope in amino acids, although to a much smaller degree under hypoxia than normoxia. This demonstrates that nitrate is taken up under hypoxic conditions and assimilated into amino acids, although to a much lesser extent than for normoxia. The similar response obtained with nodulated and non-nodulated plants indicates the rapid metabolic adaptation of nodulated plants to the presence of nitrate under hypoxia. Enrichment of N in nodules was very much weaker with a distinct enrichment pattern of amino acids (especially asparagine) suggesting that labelling arose from a tissue source external to the nodule rather than through assimilation in the nodule itself.

Chlorophyll Degradation and Formation of Colorless Chlorophyll Derivatives during Soybean (Glycine max L. Merill) Seed Maturation

The natural chlorophyll degradation results in noncolored chlorophyll catabolites (NCCs), but there are controversies if these are the final products. The formation and degradation of NCCs during soybean seed (Glycine max L. Merrill) maturation and two drying temperatures were investigated. Soybean was harvested at six maturation stages. The effect of postharvest drying at 40 and 60 degrees C on the NCC formation was analyzed by high-performance liquid chromatography (HPLC), and results were expressed as areas under the curve. All samples contained fractions with an absorption maximum at 320 nm, typical for NCC. The amounts of NCC increased until 114 days after planting and were significantly lower in advanced maturation stages. These results indicate that the NCC in soybeans might not be the final products of chlorophyll degradation. Their reduction in advanced maturation stages may be due to further metabolization. Heating soybeans at 40 and 60 degrees C promoted unnatural chlorophyll degradation and impaired the formation of NCC.

Oxidation of oxa and thia fatty acids and related compounds catalysed by 5-and 15-lipoxygenase

The modified fatty acids, (Z,Z,Z)-(octadeca-6,9,12-trienyloxy)acetic acid, (Z,Z,Z)-(octadeca-9,12,15-trienyloxy)acetic acid, (all-Z)-(eicosa-5,8,11,14-tetraenyloxy)acetic acid, (all-Z)-(eicosa-5,8,11,14-tetraenylthio)acetic acid, 3-[(all-Z)-(eicosa-5,8,11,14-tetraenylthio)]propionic acid, (all-Z)-(eicosa-5,8,11,14-tetraenylthio)succinic acid, N-[(all-Z)-(eicosa-5,8,11,14-tetraenoyl)]glycine and N-[(all-Z)-(eicosa-5,8,11,14-tetraenoyl)]aspartic acid, all react with soybean 15-lipoxygenase. The products were treated with triphenylphosphine to give alcohols, which were isolated using HPLC. Analysis of the alcohols using negative ion tandem electrospray mass spectrometry, and by comparison with compounds obtained by autoxidation of arachidonic acid, shows that each enzyme catalysed oxidation occurs at the omega -6 position of the substrate. In a similar fashion, it has been found that (Z,Z,Z)-(octadeca-6,9,12-trienyloxy)acetic acid, (Z,Z,Z)-(octadeca-9,12,15-trienyloxy)acetic acid, (all-Z)-(eicosa-5,8,11,14-tetraenylthio)acetic acid and N-[(all-Z)-(eicosa-5,8, 11.14-tetraenylthio)]propionic acid each undergoes regioselective oxidation at the carboxyl end of the polyene moiety on treatment with potato 5-lipoxygenase. Neither (all-Z)-(eicosa-5,8,11,14-tetraenylthio)succinic acid nor N-[(all-Z)-(eicosa-5,8,11,14-tetraenoyl)]aspartic acid reacts in the presence of this enzyme, while N-[(all-Z)-(eicosa-5,8,11,14-tetraenoyl)]glycine affords the C11' oxidation product. The alcohol derived from (Z,Z,Z)-(octadeca-6,9, 12-trienyloxy)acetic acid using the 15-lipoxygenase reacts at the C6' position with the 5-lipoxygenase. (C) 2001 Elsevier Science Ltd. All rights reserved.

Influência do tamanho sobre a conservação, germinação e vigor de sementes de soja (Glycine max (L.) Merr.)

O presente trabalho foi desenvolvido no Laboratório de Sementes do Departamento de Agricultura e Horticultura da E. S. A. «LUIZ DE QUEIROZ», constando de testes de germinação e de vigor (envelhecimento prococe) realizados em seis épocas bimestrais, com sementes de três cultivares de soja (Santa Rosa, IAC-2 e Viçoja), de três tamanhos (Peneira 17-grandes, Peneira 16-médias e Peneira 15 pequenas), conservadas em dois ambientes diferentes: em câmara seca e em ambiente não controlado. A análise dos dados obtidos permitiu conclusões como: a germinação variou entre cultivares e foi diretamente proporcional ao tamanho das sementes; houve decréscimo da germinação no decorrer do período considerado, sendo mais acentuado para sementes pequenas; o vigor foi maior para sementes pequenas; as sementes conservadas em câmara seca superaram as demais em todas as circunstâncias.

Produção de matéria seca, nodulação e absorção de nutrientes pela soja (Glycine max (L.) Merrill) em função de níveis de fósforo e zinco, em solos de Minas Gerais

O efeito de níveis de fósforo e zinco na produção de matéria seca, nodulação e absorção de nutrientes pela soja (Glycine max (L.) Merrill cv. 'UFV-1) foi estudado em condições de casa-de-vegetação. Foram testadas três doses de fósforo equivalentes a 0. 200 e 400 kg de P2O5/ha, e três de zinco equivalentes a 0, 15 e 30 kg de sulfato de zinco/ha, em três solos, em vasos contendo 7 kg de terra. Os solos estudados foram os seguintes: Latossolo Vermelho-Amarelo (LV), Latossolo Vermelho-Escuro, textura média (LEm), e Latossolo Vermelho-Escuro (LE). As sementes, no plantio, foram inoculadas com estirpes de Rhizobium japonicum. Foram observados aumentos da produção de materia seca das plantas e da nodulação, com a adubação fosfatada. A fertilização com zinco não alterou estes parâmetros. Produções menores de matéria seca das plantas foram verificadas no LEm, no entanto, este solo e o LV, foram os substratos que propiciaram as maiores nodulações. As concentrações de N, Ca, Mg e Zn decresceram com a adubação fosfatada, sugerindo-se um efeito de diluição, propiciado pelo intenso crescimento das plantas. A fertilização fosfatada, na maior dose, diminuiu o teor de K nas folhas velhas e aumentou-o nas novas e nas hastes, indicando ter havido translocação do referido nutriente.

Himenópteros parasitóides (Insecta, Hymenoptera) coletados em cultura de soja (Glycine max (L.)) Merril (Fabaceae), no município de Nuporanga, SP, Brasil

Parasitoid Hymenoptera collected in a soybean plantation (Glycine max (L.)) Merril (Fabaceae) at the municipal district of Nuporanga, SP, Brazil. Parasitoid Hymenoptera were collected by using Moericke trap placed in a soybean plantation (Glycine max (L.) Merril) (Fabaceae) of the variety Conquista, during the period of March 24th to April 7th, 2000. A total of 4,969 specimens of parasitoids, belonging to seven superfamilies and 15 families, were collected. Scelionidae, Encyrtidae, Aphelinidae and Trichogrammatidae were the most common families, being responsible for 41.66%, 19.42%, 11.19% and 7.35% of the total number of parasitoids collected, respectively. Other eleven families showed the relative frequency lower than 5%.

Expressão dos genes nodC, nodW e nopP em Bradyrhizobium japonicum estirpe CPAC 15 avaliada por RT-qPCR

O objetivo deste trabalho foi avaliar a expressão, por RT-qPCR, dos genes de nodulação nodC e nodW e do gene nopP da estirpe CPAC 15, que provavelmente atuam na infecção das raízes da soja. Foram realizados dois experimentos. No primeiro, a expressão dos genes foi avaliada nas células após a incubação com genisteína por 15 min, 1, 4 e 8 horas. Os resultados revelaram que os três genes apresentaram maior expressão imediatamente após o contato com o indutor (15 min). No segundo experimento, a bactéria foi cultivada na presença de indutores (genisteína ou exsudatos de sementes de soja) por 48 horas. A expressão dos três genes foi maior na presença de genisteína, com valores de expressão para nodC, nodW e nopP superiores ao controle. Os resultados obtidos confirmam a funcionalidade dos três genes na estirpe CPAC 15, com ênfase para o nopP, cuja funcionalidade em Bradyrhizobium japonicum foi descrita pela primeira vez.