Denitrification by bacteroids of an uptake hydrogenase negative (Hup-) mutant and its isogenic Hup+ parental strain of Bradyrhizobium japonicum.

International audienc

Diet-induced weight loss and phenotypic flexibility among healthy overweight adults: a randomized trial

Background: The capacity of an individual to respond to change in food intake so that postprandial metabolic perturbations are resolved, and metabolism returns to its pre-prandial state, is called phenotypic flexibility. This ability may relate to health status better than metabolic markers in a fasting state. Aims: In this parallel randomized controlled trial study, an energy-restricted healthy diet and two dietary challenges were used to assess the effect of weight loss on phenotypic flexibility. Methods: 72 overweight volunteers underwent a 12-week dietary intervention. The participants were randomized to a weight loss group (WLG) with 20% less energy or a weight maintenance group (WMG). At weeks 1 and 12, participants were assessed for body composition by magnetic resonance imaging (MRI) and quantification of markers of metabolism and insulin sensitivity by analyses of the plasma metabolome during two different dietary challenges - an oral glucose tolerance test (OGTT), and a mixed meal tolerance test (MMTT). Results: Intended weight loss was achieved in the WLG (-5.6 kg, p<0.0001) and induced significant reduction in total and regional adipose tissue as well as ectopic fat in the liver. Amino acid-based markers of insulin action and resistance such as leucine and glutamate, were reduced in the post prandial phase of the OGTT in the WLG by 11.5% and 28%, respectively, after body weight reduction. Weight loss correlated with the magnitude of changes in metabolic responses to the dietary challenges. Large inter-individual variation in metabolic responses to the weight loss was observed. Conclusion: Application of dietary challenges increased sensitivity to detect metabolic response to weight loss intervention. Large inter-individual variation was observed across a wide range of measurements allowing the identification of distinct responses to the weight loss intervention, and mechanistic insight into the metabolic response to weight loss

Selection of common bean lines, recombinant inbred lines and commercial genotypes tolerant to low phosphorus availability in an acrisol soil on the basis of root traits and grain yield

Prepared by the Joint FAO/IAEA Division of Nuclear Techniques in Food and AgricultureCommon bean (Phaseolus vulgaris L.) is the most important food legume for human consumption worldwide and especially in Latin America and Africa, but low soil phosphorus (P) availability limits grain production in these areas. For these reason eighty five recombinant inbred lines (RILs) of BAT 477 x DOR 364 and twenty commercial bean genotypes were sown in plots in an Acrisol soil with low P availability to evaluate nine root traits and grain yield. The study was carried out in Pinar del Rio province in Cuba between November 2006 and February 2009. The plots received basal fertilization (N and K) and P fertilization between 15 and 90 kg P2O5 ha-1. Ten plants weresampled from each plot at R6 pod fill to evaluate root traits and shoot biomass, and at R9 physiological maturity to estimate grain yield. The 85 RILs showed great variability for root traits, grain yield and P stress tolerance calculated as relative grain yield. The commercial bean lines also showed large diversity in yield parameters. Principal Component Analysis showed that there were high and significant correlations between root traits (basal root number, primary root depth, adventitious root length and adventitious root number) and grain yield parameters (grain yield at 15 P level and relative grain yields). Adventitious root traits showed the greatest correlation with yield under low P. Promising RILs included 75.1.1, 60.1.1, 38.1.1, 14.1.1 and 38.1.1 and promising commercial beanlines included ICA Pijao, BAT 482, ICA 23, BAT 24 and BAT 832

Circulating Polyunsaturated Fatty Acids as Biomarkers for Dietary Intake across Subgroups : The CODAM and Hoorn Studies

Aims: To evaluate whether participant characteristics and way of expressing circulating fatty acids (FA) influence the strengths of associations between self-reported intake and circulating levels of linoleic acid (LA), alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Methods: Cross-sectional analyses were performed in pooled data from the CODAM (n = 469) and Hoorn (n = 702) studies. Circulating FA were measured by gas liquid chromatography and expressed as proportions (% of total FA) and concentrations (µg/mL). Dietary intakes were calculated from a validated food frequency questionnaire. Effects of participant characteristics on associations between dietary and circulating FA were calculated using interaction analyses. Results: Standardized regression coefficients between dietary FA and proportions of circulating FA (% of total FA) were LA β = 0.28, ALA β = 0.13, EPA β = 0.34, and DHA β = 0.45. Body mass index (BMI), waist circumference, and presence of CVD influenced associations for LA; gender influenced LA, EPA, and DHA; alcohol intake influenced LA and DHA; and glucose tolerance status influenced ALA (p values interaction <0.05). Coefficients for circulating FA as concentrations were LA β = 0.19, ALA β = 0.10, EPA β = 0.31, and DHA β = 0.41. Conclusions: This study suggests that characteristics such as BMI, alcohol intake, and expressing circulating FA as proportions or concentrations, influence associations between dietary and circulating FA

Supplementary Material for: Circulating Polyunsaturated Fatty Acids as Biomarkers for Dietary Intake across Subgroups: The CODAM and Hoorn Studies

<b><i>Aims:</i></b> To evaluate whether participant characteristics and way of expressing circulating fatty acids (FA) influence the strengths of associations between self-reported intake and circulating levels of linoleic acid (LA), alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). <b><i>Methods:</i></b> Cross-sectional analyses were performed in pooled data from the CODAM (<i>n</i> = 469) and Hoorn (<i>n</i> = 702) studies. Circulating FA were measured by gas liquid chromatography and expressed as proportions (% of total FA) and concentrations (µg/mL). Dietary intakes were calculated from a validated food frequency questionnaire. Effects of participant characteristics on associations between dietary and circulating FA were calculated using interaction analyses. <b><i>Results:</i></b> Standardized regression coefficients between dietary FA and proportions of circulating FA (% of total FA) were LA β = 0.28, ALA β = 0.13, EPA β = 0.34, and DHA β = 0.45. Body mass index (BMI), waist circumference, and presence of CVD influenced associations for LA; gender influenced LA, EPA, and DHA; alcohol intake influenced LA and DHA; and glucose tolerance status influenced ALA (<i>p</i> values interaction <0.05). Coefficients for circulating FA as concentrations were LA β = 0.19, ALA β = 0.10, EPA β = 0.31, and DHA β = 0.41. <b><i>Conclusions:</i></b> This study suggests that characteristics such as BMI, alcohol intake, and expressing circulating FA as proportions or concentrations, influence associations between dietary and circulating FA

Fotossíntese em alfafa (Medicago sativa L.) sob supressão e ressuprimento de fosfato Photosynthesis in alfalfa (Medicago sativa L.) under phosphate suppression and ressuply

Neste estudo, foram avaliados os efeitos da supressão e do ressuprimento de fosfato (Pi) sobre a fotossíntese e eficiência fotoquímica de plantas de Medicago sativa cv. Flórida 77, em diferentes estádios do desenvolvimento vegetativo (V3, V4) e reprodutivo (R6, R8). O ensaio foi conduzido em casa de vegetação e as plantas cultivadas na solução nutritiva de HOAGLAND & ARNON (1950), contendo 0,14mmol L-1 de Pi. A supressão de Pi por dez dias reduziu os teores de fósforo nas folhas amostradas, em todos os estádios do desenvolvimento. Entretanto, com o ressuprimento, somente nos estádios vegetativos, os valores foram semelhantes ao tratamento controle. A fotossíntese por área foliar, em todos os estádios do desenvolvimento diminuiu com a supressão de Pi. De modo geral, o ressuprimento de Pi à solução nutritiva resultou em recuperação na fotossíntese, excetuando-se as plantas no estádio V3, uma indicação de que o período de supressão não causou danos permanentes no aparato fotossintético. Os teores dos pigmentos fotossintéticos e a eficiência fotoquímica do fotossistema II (FS II), avaliada pela relação Fv/Fm, não foram alterados quando as plantas foram submetidas à supressão de Pi. Esse resultado demonstra que o transporte de elétrons através do FS II não limitou a fotossíntese nas folhas amostradas, sob supressão de Pi, sugerindo que a supressão causou efeito mais pronunciado na etapa bioquímica da fotossíntese.<br>This work evaluated the phosphate (Pi) suppression and ressupply on photosynthesis and photochemical efficiency from Medicago sativa plants cv. Florida 77, in different growth stages (V3 and V4) and reproductive (R6 and R8). The experiment was performed in a greenhouse, the plants being cultivated in HOAGLAND & ARMOND (1950) nutritive solution containing 0,14mmol L-1 of Pi. Pi suppression for ten days reduced Pi levels in sampled leaves, in all growth stages. However, with the re-supply only in the vegetative stages the values were similar to the control treatments. Photosynthesis per foliar area in all growth stages decreased with Pi suppression. In general, Pi ressupply into the nutritive solution resulted in recovery of photosynthesis, except for V3 plants, indicating that the suppression period did not cause permanent damage to the photosynthetic apparatus. Levels of photosynthetic pigments and the photosystem II (PS-II) photochemical efficiency evaluated as the Fv/Fm ratio were not altered when plants were submitted to Pi suppression. These results show that electons transport through PS-II did not limit photosynthesis in the sampled leaves under Pi supression, suggesting that Pi suppression caused a more pronunciated effect in the biochemical step of photosynthesis