Search

Background: Plant raw materials are commonly used in aquafeeds, as marine resources are unsustainable. However, full plant-based diets lead to poorer fish growth performance.Objective: We aimed to understand the metabolic effects of a yeast fraction as a protein supplement in a plant-based diet and to integrate such effects with phenotypic traits as a new approach to assess the interest of this raw material.Methods: Juvenile (49 g) rainbow trout (Oncorhynchus mykiss) were fed graded levels of a yeast protein-rich fraction (5% YST05, 10% YST10, 15% YST15) in a plant-based diet (PB) for 84 d. Final body weight, feed conversion ratio, and hepatosomatic and viscerosomatic indexes were measured. Plasma, liver, and muscle 1H-NMR fingerprints were analyzed with principal component analyses, and their metabolite patterns were clustered according to the yeast level to identify concomitant metabolic effects. A regression modeling approach was used to predict tissue metabolite changes from plasma fingerprints.Results: In tissues, the patterns of metabolite changes followed either linear trends with the gradual inclusion of a yeast fraction (2 patterns out of 6 in muscle, 1 in liver) or quadratic trends (4 patterns in muscle, 5 in liver). Muscle aspartate and glucose (395 and 138% maximum increase in relative content compared with PB, respectively) revealing modification in energy metabolism, as well as modification of liver betaine (163% maximum increase) and muscle histidine (57% maximum decrease) related functions, indicates that the yeast fraction could improve growth in several ways. The highest correlation between measured and predicted metabolite intensities in a tissue based on plasma fingerprints was observed for betaine in liver (r = 0.80).Conclusions: These findings herald a new approach to assess the plurality of metabolic effects induced by diets and establish the optimal level of raw materials. They open the way for using plasma as a noninvasive matrix in trout nutrition studies. [ABSTRACT FROM AUTHOR]

In young tomato plants, modifications in mineral composition by short-term cadmium (Cd) treatments have been extensively examined. However, long-term Cd treatments have been fewly investigated, and little information about Cd-stress in fruiting plants is available. In the present work, we examined the changes in mineral nutrients of roots, stems, leaves, flowers, seeds and fruit pericarp of tomato plants submitted to a long-term Cd stress. After a 90-day culture period in hydroponic contaminated environment (0, 20 and 100 μM CdCl 2 ), fruit production was affected by increasing external Cd levels, with the absence of fruit set at 100 μM Cd. Meanwhile, Cd altered the plant mineral contents with an element- and organ-dependent response. At 20 μM, Cd triggered a significant increase in Ca content in roots, mature leaves, flowers and developing fruits. However, at 100 μM Cd, Ca content was reduced in shoots, and enhanced in roots. Cd stress reduced Zn and Cu contents in shoots and increased them in roots. High Cd level led to a significant decrease in K and Mg content in all plant organs. Furthermore, Fe concentration was reduced in roots, stems and leaves but increased in flowers, seeds and red ripe fruits. Our results suggest that tomato plants acclimatize during long-term exposure to 20 μM Cd, while 100 μM Cd results in drastic nutritional perturbations leading to fruit set abortion. [ABSTRACT FROM AUTHOR]

Root-knot nematodes are obligatory plant parasitic worms that establish and maintain an intimate relationship with their host plants. During a compatible interaction, these nematodes induce the redifferentiation of root cells into multinucleate and hypertrophied giant cells (GCs). These metabolically active feeding cells constitute the exclusive source of nutrients for the nematode. We analyzed the modifications of water status, ionic content and accumulation of metabolites in development and mature galls induced by Meloidogyne incognita and in uninfected roots of Medicago truncatula plants. Water potential and osmotic pressure are significantly modified in mature galls compared to developing galls and control roots. Ionic content is significantly modified in galls compared to roots. Principal component analyses of metabolite content showed that mature gall metabolism is significantly modified compared to developing gall metabolism. The most striking differences were the three-fold increase of trehalose content associated to the five-fold diminution in glucose concentration in mature galls. Gene expression analysis showed that trehalose accumulation was, at least, partially linked to a significantly lower expression of the trehalase gene in mature galls. Our results point to significant modifications of gall physiology during maturation. [ABSTRACT FROM AUTHOR]

Highlights: [•] The aroma of Cucumis melo fruit highly influences financial value. [•] A robust method of fruit aroma sampling followed by TD-GC–MS detection was developed. [•] Aroma was reduced in non-climacteric fruit, in climacteric melons shelf-life greatly affected aroma. [•] Comparisons to SPME-GC–MS has indicated the validity of the new method. [•] The new method is suited for rapid assessment of fruit aroma and quality. [ABSTRACT FROM AUTHOR]

Abstract: Polyamines are involved in crucial plant physiological events, but their roles in fruit development remain unclear. We generated transgenic tomato plants that show a 1.5- to 2-fold increase in polyamine content by over-expressing the spermidine synthase gene, which encodes a key enzyme for polyamine biosynthesis. Pericarp-columella and placental tissue from transgenic tomato fruits were subjected to 1H-nuclear magnetic resonance (NMR) for untargeted metabolic profiling and high-performance liquid chromatography-diode array detection for carotenoid profiling to determine the effects of high levels of polyamine accumulation on tomato fruit metabolism. A principal component analysis of the quantitative 1H NMR data from immature green to red ripe fruit showed a clear discrimination between developmental stages, especially during ripening. Quantification of 37 metabolites in pericarp-columella and 41 metabolites in placenta tissues revealed distinct metabolic profiles between the wild type and transgenic lines, particularly at the late ripening stages. Notably, the transgenic tomato fruits also showed an increase in carotenoid accumulation, especially in lycopene (1.3- to 2.2-fold), and increased ethylene production (1.2- to 1.6-fold) compared to wild-type fruits. Genes responsible for lycopene biosynthesis, including phytoene synthase, phytoene desaturase, and deoxy-d-xylulose 5-phosphate synthase, were significantly up-regulated in ripe transgenic fruits, whereas genes involved in lycopene degradation, including lycopene-epsilon cyclase and lycopene beta cyclase, were down-regulated in the transgenic fruits compared to the wild type. These results suggest that a high level of accumulation of polyamines in the tomato regulates the steady-state level of transcription of genes responsible for the lycopene metabolic pathway, which results in a higher accumulation of lycopene in the fruit. [ABSTRACT FROM AUTHOR]

Abstract: A metabolomics approach using 1H NMR and GC–MS profiling of primary metabolites and quantification of adenine nucleotides with luciferin bioluminescence was employed to investigate the spatial changes of metabolism in melon fruit. Direct 1H NMR profiling of juice collected from different locations in the fruit flesh revealed several gradients of metabolites, e.g. sucrose, alanine, valine, GABA or ethanol, with increase in concentrations from the periphery to the center of the fruit. GC–MS profiling of ground samples revealed gradients for metabolites not detected using 1H NMR, including pyruvic and fumaric acids. The quantification of adenine nucleotides highlighted a strong decrease in both ATP and ADP ratios and the adenylate energy charge from the periphery to the center of the fruit. These concentration patterns are consistent with an increase in ethanol fermentation due to oxygen limitation and were confirmed by observed changes in alanine and GABA concentrations, as well as other markers of hypoxia in plants. Ethanol content in melon fruit can affect organoleptic properties and consumer acceptance. Understanding how and when fermentation occurred can help to manage the culture and limit ethanol production. [Copyright &y& Elsevier]

Abstract: Arabidopsis thaliana was transformed with a Sorghum C4 PEPC cDNA under the control of the 35S promoter. Primary transformants were isolated and classified on a seed PEPC activity basis: A lines (two-fold increase) and B lines (four-fold increase). Primary transformants also expressed the C4 PEPC in leaves (up to a 10-fold increase in activity). In seeds, ectopically expressed PEPC impacted on dry weight and total protein content that were increased by up to 30%. In the stable progeny of A and B lines, the increase in PEPC activity was amplified in seeds; however, a decrease in PEPC content and activity (inversely proportional to seed levels) was observed in maternal tissues (leaves and siliques). This was due to the absence of the exogenous C4 PEPC and a partial decrease in the endogenous C3 PEPC forms (mRNA, protein and activity). There was no apparent compensation by a PEPC hyperphosphorylation. In these plants, the anaplerotic pathway flux was altered (notably, a decrease in organic acids and glutamine levels) as judged by 1H NMR metabolite profiling. Whereas in the corresponding seeds (four- to eight-fold increase in PEPC activity) there was no increase in protein and seed mass, but a moderate decrease in lipid content was observed (compared to control plants). Under normal culture conditions, the transformants (primary and progeny) did not show any apparent growth phenotype or modification in seed production per plant. However, the A and B lines exhibited severe growth defects when salt stressed by LiCl. [Copyright &y& Elsevier]

Abstract: Many variables such as total soluble sugars, total titratable acidity, nitrogen and phenolic compounds balance, contribute to describe grape quality. They vary strongly with genetic (cultivars) and environmental (climate, soil, and cultural practices together referred to as “terroir”, and vintage) factors. The aim of this work was to determine changes in metabolite fingerprints of grape berry skins of ‘Merlot noir’, ‘Carbernet franc’ or ‘Cabernet Sauvignon’ cultivars harvested in 2002, 2003 and 2004 from five geographical locations in Bordeaux (south-west of France) to better understand the factors influencing the grape berry composition. 1H NMR spectroscopy was used to determine metabolic profiles of skin extracts of berries harvested at maturity. Before analysis by multivariate statistical methods, spectral data were reduced (sum of intensities over 0.04ppm spectral domains) and normalized to generate 183 variables describing the entire spectra. Principal component analysis (PCA) and partial least squares (PLS) chemometric methods were applied to describe sample variability and show clustering of samples. These chemometric methods gave a good separation of samples according to vintages. PLS allowed us to pinpoint spectral domains corresponding to metabolites contributing to the differences between vintages, including sugars (glucose, fructose and sucrose), organic acids (tartaric, malic, citric and succinic acids), and amino acids (proline, arginine, GABA, valine, alanine, leucine and isoleucine). Conversely, soils classified according to their capacity to provide water to the vines, could not be discriminated by 1H NMR metabolic fingerprinting of the berries. The vintage effect on grape metabolic profiles prevailed over the soil effect. This emphasizes the fact that a typical vineyard is defined by its most frequent climatic traits such as the seasonal sum of temperatures and water balance. [Copyright &y& Elsevier]