High Levels Of Sucrose Research Articles

Nutritivni sastav organski i konvencionalno proizvedenih namirnica

Given the fact that the nutritional value, safety and health status of food produced by conventional agriculture vary around the world, the system of organic farming is emerging as a system that achieves a sustainable production of healthy and safe food, free of pesticide residues. This paper presents evidence that organic foods compared to conventional contain significantly less nitrates, a higher level of dry substance and minerals (especially Fe, Mg and P), vitamin C, essential amino acids and total sugars, then the phenolic compounds, while foods of animal origin contain more unsaturated fatty acids. As for the level of protein, it is generally lower in organic foods. The current scientific data indicate that there is an insufficient number of studies on vitamin levels, in particular b-carotene and vitamin B group. Organically produced fruits and vegetables (in particular apple, cherry, currants, sugar beet, beetroot, carrot, spinach, kale and potatoes) contain higher levels of sucrose and total all sugars. When it comes to animal products, the current available data are insufficiently documented due to different farming systems on farms. However, studies show that chicken eggs and cow's milk do not show significant differences in protein content compared to conventionally produced, organic cow's milk products contain less lipids, while organic chicken meat has a much higher level of iron. However, strict rules laid down by the system of organic production provides food production that meets high quality standards.

Physicochemical Characteristics and Composition of Three Morphotypes of Cyperus esculentus Tubers and Tuber Oils.

Tuber characteristics and nutrient composition of three morphotypes of Cyperus esculentus tubers and tuber oils were determined. The mean value for length and width of the tuber and one thousand dried tuber weights ranged from 0.98 to 1.31 cm, 0.90 to 1.19 cm, and 598 to 1044 g, respectively. Tubers displayed high level of starch (30.54–33.21 g 100 g−1), lipid (24.91–28.94 g 100 g−1), and sucrose (17.98–20.39 g 100 g−1). The yellow tubers had significantly higher content in lipid compared to black ones. Levels of ascorbic acid, tocopherol, and β-carotene of the three morphotypes differed significantly. Yellow ones (morphotypes 1 and 2) were the richest in tocopherol and the poorest in β-carotene. Saturated fatty acid content of morphotype 2 was significantly lower than that of morphotypes 1 and 3. Morphotype 3 had the significantly lowest PUFA content compared to morphotypes 1 and 2. Morphotype 1 was found to be richer in Ca, Cu, and Mn contents. Al, Mg, P, S, and Si were most abundant in morphotype 2. Morphotype 3 had the highest content of Cl, K, and Zn.

The sh2-R allele of the maize shrunken-2 locus was caused by a complex chromosomal rearrangement.

The mutant that originally defined the shrunken - 2 locus of maize is shown here to be the product of a complex chromosomal rearrangement. The maize shrunken-2 gene (sh2) encodes the large subunit of the heterotetrameric enzyme, adenosine diphosphate glucose pyrophosphorylases and a rate-limiting enzyme in starch biosynthesis. The sh2 gene was defined approximately 72 years ago by the isolation of a loss-of-function allele conditioning a shrunken, but viable seed. In subsequent years, the realization that this allele, termed zsh2-R or sh2-Reference, causes an extremely high level of sucrose to accumulate in the developing seed led to a revolution in the sweet corn industry. Now, the vast majority of sweet corns grown throughout the world contain this mutant allele. Through initial Southern analysis followed by genomic sequencing, the work reported here shows that this allele arose through a complex set of events involving at least three breaks of chromosome 3 as well as an intra-chromosomal inversion. These findings provide an explanation for some previously reported, unexpected observations concerning rates of recombination within and between genes in this region.

Functionality study of Na6PMo11FeO40 as a mushroom tyrosinase inhibitor

The inhibitory effects of iron-substituted phosphomolybdic acid (Na6PMo11FeO40, abbreviated as PMo11Fe) on mushroom tyrosinase were investigated. The Native-PAGE results show that PMo11Fe has an inhibitory effect on tyrosinase. A spectrophotometric analysis shows that PMo11Fe is a reversible and noncompetitive inhibitor with KI=KIS=0.47mmolL−1. The effects of PMo11Fe on the preservation of lotus root slices were studied. The results show that PMo11Fe can significantly slow the browning rate of lotus root slices, inhibit the activity of polyphenol oxidase (PPO), enhance the activity of peroxidase (POD) and superoxide dismutase (SOD), maintain high levels of glutathione (GSH), ascorbic acid (ASA) and sucrose and control the peroxidation degree of fresh-cut fruits and vegetables. This study may help to elucidate the design of mushroom tyrosinase inhibitors of polyoxometalates (abbreviated as POMs) and a theoretical basis for the use of POMs to inhibit fruit spoilage.

Assessment of green coffee bean metabolites dependent on coffee quality using a 1H NMR-based metabolomics approach

There is increasing interest in the coffee grade or quality with the rise of coffee consumption, but a classical, chemical analysis-based understanding of the coffee bean grade is still limited. We therefore report the identification of green coffee bean metabolites related to coffee bean quality using a 1H NMR-based metabolomic analysis of well-established specialty-grade green coffee beans, in particular, of a single species (Coffea arabica). The higher levels of sucrose and the lower levels of γ-aminobutyric acid (GABA), quinic acid, choline, acetic acid and fatty acids observed in specialty or high-grade green coffee beans, compared to commercial-grade beans, were suggestive to be multiple markers for characterizing specialty green coffee bean. In particular, variations in sucrose and GABA levels between specialty and commercial coffees could be a consequence of different environmental conditions, for example, biotic or abiotc stresses, at growing regions. These results highlight an alternative method of metabolomic approach for grading green coffee bean.

Measuring whole plant CO2 exchange with the environment reveals opposing effects of the gin2–1 mutation in shoots and roots of Arabidopsis thaliana

Using a cuvette for simultaneous measurement of net photosynthesis in above ground plant organs and root respiration we investigated the effect of reduced leaf glucokinase activity on plant carbon balance. The gin2–1 mutant of Arabidopsis thaliana is characterized by a 50% reduction of glucokinase activity in the shoot, while activity in roots is about fivefold higher and similar to wild type plants. High levels of sucrose accumulating in leaves during the light period correlated with elevated root respiration in gin2–1. Despite substantial respiratory losses in roots, growth retardation was moderate, probably because photosynthetic carbon fixation was simultaneously elevated in gin2–1. Our data indicate that futile cycling of sucrose in shoots exerts a reduction on net CO2 gain, but this is over-compensated by the prevention of exaggerated root respiration resulting from high sucrose concentration in leaf tissue.

Characterization of horizontally transferred β-fructofuranosidase (ScrB) genes in Agrilus planipennis.

The emerald ash borer (Agrilus planipennis) is an important invasive insect pest of Fraxinus spp. that feeds on host tissues containing high levels of sucrose. However, little is known about how it digests sucrose. Here, using larval midgut transcriptome data and preliminary genome sequence efforts, two β-fructofuranosidase-encoding ScrB genes, AplaScrB-1 and AplaScrB-2, were identified, and proved to reside within the A. planipennis genome. Homology and phylogenetic analysis revealed that they were acquired by A. planipennis via horizontal gene transfer (HGT) from bacteria, possibly an event independent from that reported in bark beetles (eg ScrB genes). Microsynteny between A. planipennis DNA scaffold #2042940, which hosts AplaScrB-1, and a region in the Tribolium castaneum chromosome LG4 suggested that A. planipennis gained this gene after the separation of Buprestidae and Tenebrionidae. Although both of the putative AplaScrB proteins have conserved β-fructofuranosidase motifs, only AplaScrB-2 was predicted to be a secretory protein. Expression of AplaScrB-1 seemed constitutive during development and in all tissues examined, whereas AplaScrB-2 showed a peak expression in adults and in the midgut. We propose that acquisition of these genes by A. planipennis from bacteria is adaptive, and specifically AplaScrB-2 is involved in breaking down dietary sucrose to obtain energy for development.

English

Micrografting is an in vitro grafting technique which involves the placement of a meristem or shoot tip explant onto a decapitated rootstock that has been grown aseptically from seed or micropropagated cultures. Following early experiments of micrografting in ivy and chrysanthemum, the technique has been used in woody species, especially fruit trees. Major work was carried out in different Citrus species for the elimination of various viral diseases. In vitro micrografting has been used for improvement and multiplication of fruit trees as the technique has potential to combine the advantages of rapid in vitro multiplication with the increased productivity that results from grafting superior rootstock and scion combinations. Successful micrografting protocols have been developed for various fruit crops including almond, apple, cherry, chestnut, Citrus, grapes, mulberry, olive, peach, pear, pistacio, walnut, etc. Special techniques have been used for increasing the percentage of successful micrografts with the use of growth regulators, etiolation treatments, antioxidants, higher sucrose levels, silicon tubes, etc. The technique has great potential for improvement and large scale multiplication of fruit plants. It has been used on commercial scale for production of virus-free plants in fruit crops and viroid free plants in Citrus. Micrografting has also been used in prediction of incompatibility between the grafting partners, histological studies, disease indexing, production of disease-free plants particularly resistant to soil borne pathogens and multiplication of difficult to root plants.   Key words: Fruit crops, graft incompatibility, crop improvement, micrografting, propagation, shoot tip grafting.

Improvement of flavour quality and consumer acceptance during postharvest ripening in greenhouse peaches by carbon dioxide enrichment

In this study we assessed the impact of carbon dioxide enrichment (CDE) on flavour quality development of peach fruit, using peach trees grown in a greenhouse with a carbon-dioxide-enriched atmosphere. Fruit sugar, organic acids, volatiles contents and consumer acceptability were investigated, focusing on the period of postharvest ripening. Higher levels of sucrose, lactones, norisoprenoids, and lower levels of malic acid were found in CDE-treated fruit than those in the control fruit grown under normal conditions. We also measured significantly elevated amounts of pyruvic acid, precursors of volatile compounds, linoleic acid and linolenic acid as a result of CDE. Additionally, CDE-treated fruit were relatively well accepted by consumers compared to the control fruit. These results suggested that CDE can markedly improve the flavour quality and consumer acceptance of greenhouse-grown peaches. The possible mechanism could be that CDE increased precursors available for the biosynthesis of flavour compounds through regulation of photosynthesis.

The improved resistance to high salinity induced by trehalose is associated with ionic regulation and osmotic adjustment in Catharanthus roseus

The effects of exogenous trehalose (Tre) on salt tolerance of pharmaceutical plant Catharanthus roseus and the physiological mechanisms were both investigated in this study. The results showed that the supplement of Tre in saline condition (250 mM NaCl) largely alleviated the inhibitory effects of salinity on plant growth, namely biomass accumulation and total leaf area per plant. In this saline condition, the decreased level of relative water content (RWC) and photosynthetic rate were also greatly rescued by exogenous Tre. This improved performance of plants under high salinity induced by Tre could be partly ascribed to its ability to decrease accumulation of sodium, and increase potassium in leaves. The exogenous Tre led to high levels of fructose, glucose, sucrose and Tre inside the salt-stressed plants during whole the three-week treatment. The major free amino acids such as proline, arginine, threonine and glutamate were also largely elevated in the first two-week course of treatment with Tre in saline solution. It was proposed here that Tre might act as signal to make the salt-stressed plants actively increase internal compatible solutes, including soluble sugars and free amino acids, to control water loss, leaf gas exchange and ionic flow at the onset of salt stress. The application of Tre in saline condition also promoted the accumulation of alkaloids. The regulatory role of Tre in improving salt tolerance was optimal with an exogenous concentration of 10 mM Tre. Larger concentrations of Tre were supra-optimum and adversely affected plant growth.

Osmotic stress stimulates shoot organogenesis in callus of rice (Oryza sativa L.) via auxin signaling and carbohydrate metabolism regulation

This study aimed to clarify the possible mechanism of endogenous phytohormone signaling and carbohydrate metabolism during shoot organogenesis induced by osmotic stress in rice (Oryza sativa L. cv. Tainung 71) callus. Non-regenerable calli derived from Tainung 71 immature embryos were inoculated on Murashige and Skoog medium containing 10 μM 2,4-D. They turned to highly regenerable calli (HRC) (regeneration frequency more than 75 %) with lower calli fresh weight and water content when 0.6 M sorbitol was supplemented into the medium. The regeneration frequency was prominently decreased to 25 % while an auxin transport inhibitor, 2,3,5-triiodobenzoic acid (TIBA), was added into the sorbitol-treated medium. It suggested that endogenous auxin signal may be involved in the induction of HRC under osmotic stress treatment. As well, HRC showed high levels of glucose, sucrose, and starch and high expression of cell wall-bound invertase 1, sucrose transporter 1 (OsSUT1), OsSUT2, PIN-formed 1, and late embryogenesis abundant 1 (OsLEA1) genes. Their expressions are all dramatic inhibited except OsLEA1 under TIBA treatment. It suggests a key role of auxin may be linked to the effect of shoot regeneration under osmotic stress treatment. Therefore, we present a putative hypothesis for regenerable calli induction by osmotic stress treatment in rice. Osmotic stress may regulate endogenous levels of auxin interacting with abscisic acid, then affect carbohydrate metabolism to trigger callus initiation and further shoot regeneration in rice.

Comparison of physicochemical parameters in royal jelly from Romania and Bulgaria.

Royal jelly is a highly active natural biological substance secreted from the hypopharyngeal and mandibular glands of young worker honeybees ( Apis mellifera ). The main quality parameters of royal jelly composition are water, pr oteins, carbohydrates, lipids, 10-hydroxy-2- decenoic acid, ash, pH and acidity. The aim of this study is to compare physicochemical parameters in royal jelly samples from Romania and Bulgaria in or der to assess whether there are any differences between the samples from the both countries. The fo llowing parameters: proteins by Folin-Ciocalteu reagent; sugars (fructose, glucose, sucrose) by HPL C; water by refractometer and direct drying; total acidity by titration with 0.1 N NaOH and pH-potentiometrically were measured in 35 Bulgarian and 34 Romanian royal jelly samples collected from diff erent regions of both countries. The values obtained for parameters in samples from Romania are as follow: water 62.50±3.52%, proteins 13.04±1.87%, fructose 5.39±1.12%, glucose 5.41±1.45%, sucrose 1.19±0.67%, pH 3.99±0.09 and total acidity 3.78±0.53 ml 0.1 N NaOH/g. The samples from Bulgaria gave the following results: water 62.13±1.90%, proteins 15.83±2.58%, fructose 4.84±0.81%, glucose 4.51±1.05%, sucrose 1.92±1.21%, pH 3.85±0.18 and total acidity 3.90±1.42 ml 0.1 N NaOH/g. Higher levels of protein and sucrose and lower levels of fructose were found in Bulgarian royal jelly. Differences in climate between the two countries, different equipments use d for analysis, even the methods used are the same and RJ intrinsic heterogeneity can influence the co mposition of the product.

Investigation of the Chemomarkers Correlated with Flower Colour in Different Organs of Catharanthus roseus Using NMR‐based Metabolomics

Flower colour is a complex phenomenon that involves a wide range of secondary metabolites of flowers, for example phenolics and carotenoids as well as co-pigments. Biosynthesis of these metabolites, though, occurs through complicated pathways in many other plant organs. The analysis of the metabolic profile of leaves, stems and roots, for example, therefore may allow the identification of chemomarkers related to the final expression of flower colour. To investigate the metabolic profile of leaves, stems, roots and flowers of Catharanthus roseus and the possible correlation with four flower colours (orange, pink, purple and red). (1) H-NMR and multivariate data analysis were used to characterise the metabolites in the organs. The results showed that flower colour is characterised by a special pattern of metabolites such as anthocyanins, flavonoids, organic acids and sugars. The leaves, stems and roots also exhibit differences in their metabolic profiles according to the flower colour. Plants with orange flowers featured a relatively high level of kaempferol analogues in all organs except roots. Red-flowered plants showed a high level of malic acid, fumaric acid and asparagine in both flowers and leaves, and purple and pink flowering plants exhibited high levels of sucrose, glucose and 2,3-dihydroxy benzoic acid. High concentrations of quercetin analogues were detected in flowers and leaves of purple-flowered plants. There is a correlation between the metabolites specifically associated to the expression of different flower colours and the metabolite profile of other plant organs and it is therefore possible to predict the flower colours by detecting specific metabolites in leaves, stems or roots. This may have interesting application in the plant breeding industry.

Bone quality and strength are greater in growing male rats fed fructose compared with glucose

Optimization of peak bone mass during adolescence is important for osteoporosis prevention. Studies in rodents and humans have demonstrated the harmful effects of sugar intake on bone health. With the high levels of sucrose in the diets of adolescents, it is necessary to understand the influence of glucose and fructose on growing bones. This study compared the effects of dietary glucose and fructose on bone formation, microarchitecture, and strength. Because of the different metabolic effects of glucose and fructose, we hypothesized that their individual effects on bone would be different. Eighteen male Sprague-Dawley rats (age, 60 days) were randomly assigned to high-fructose (n = 9; 40% fructose, 10% glucose) or high-glucose diet (n = 9; 50% glucose) for 12 weeks. Bone measurements included histology and histomorphometry of trabecular bone in the distal femur and a 3-point bending test of the whole tibia. Whole liver mass and postprandial serum glucose, insulin, and triglycerides were used to assess differences in energy metabolism between the diets. There were no differences in food intake, body weight, or visceral adiposity between groups, but fructose consumption led to heavier livers (P = .001) and elevated serum triglycerides (P = .00). The distal femurs of fructose-fed rats had greater bone volume (bone volume/total volume; P = .03), lower bone surface (bone surface/bone volume; P = .02), and thicker trabeculae (trabecular thickness; P = .01). The tibias of the fructose-fed rats also withstood a greater maximum flexure load (P = .032). These results indicate that consumption of the high-fructose diet resulted in stronger bones with enhanced microarchitecture than consumption of the high-glucose diet.

Microtuberization, minitubers formation and in vitro shoot regeneration from bud sprout of potato (Solanum tuberosum L.) cultivar K. badshah

Kufri badshah is one of the important medium maturing, blight resistant potato varieties with round to oblong tubers; it has yellowish skin, shallow eye and white pulp. This variety is popular among farmers. The study on development of tissue culture protocol was carried out using sprout as an explant for initiation of culture in MS media supplemented with eleven different combinations of growth hormones: indole butyric acid (IBA), kinetin, naphthalene acetic acid (NAA) and 2,4-dichlorophenoxy acetic acid (2,4-D). The response for growth proliferation was observed. The treatment involving a combination of IBA, kinetin, NAA and 2,4-D gave good response for growth of shoot. The resultant shoots were subcultured further using nodal cutting as explants in same media for further multiplication. The developed plantlets were hardened in green house. Hardened plants were transplanted in the soil for further growth and development. The plants yielded 3-17 healthy minitubers. For microtuber production, high level of sucrose (8%) gave promising results than low level of sucrose (3%). Keywords: Kufri badshah , explants, indole butyric acid (IBA), kinetin, naphthalene acetic acid (NAA), 2,4-dichlorophenoxy acetic acid (2,4-D) and microtuber. African Journal of Biotechnology Vol. 12(38), pp. 5640-5647

Evaluation of sugar, free amino acid, and organic acid compositions of different varieties of vegetable soybean (Glycine max [L.] Merr)

Vegetable soybean is rich in nutrients and is known to possess favourable sensory characteristics, which contribute to its importance and popularity as a consumed crop worldwide. A comparative study was conducted to evaluate the composition of sugars, free amino acids, and organic acids in several Chinese vegetable soybean varieties through proton nuclear magnetic resonance spectroscopy (1H NMR). The different vegetable soybeans showed considerable variations in their sugar (15.131–33.979mg/g dry matter), total free amino acid (4.581–10.180mg/g dry matter), and organic acid (3.754–6.752mg/g dry matter) contents. The vegetable soybean samples were effectively divided into four groups based on the principal component and cluster analyses of the metabolic profiles. This study suggests that the TD6 and ND4 varieties are rich sources of asparagine and malate, whereas HD8 contains higher levels of sucrose, and the SC254 and XD17 samples exhibit higher levels of alanine, glutamate, glycine, and serine. The selection of the right vegetable soybean variety may provide a good source of nutrients for nutraceutical applications, and the differences in the metabolic profiles may be used for quality control.

Cross-talk interactions of exogenous nitric oxide and sucrose modulates phenylpropanoid metabolism in yellow lupine embryo axes infected with Fusarium oxysporum

The aim of the study was to examine cross-talk of exogenous nitric oxide (NO) and sucrose in the mechanisms of synthesis and accumulation of isoflavonoids in embryo axes of Lupinus luteus L. cv. Juno. It was verified whether the interaction of these molecules can modulate the defense response of axes to infection and development of the pathogenic fungus Fusarium oxysporum f. sp. lupini. Sucrose alone strongly stimulated a high level of genistein glucoside in axes pretreated with exogenous nitric oxide (SNP or GSNO) and non-pretreated axes. As a result of amplification of the signal coming from sucrose and GSNO, high isoflavonoids accumulation was observed (+Sn+GSNO). It needs to be stressed that infection in tissues pretreated with SNP/GSNO and cultured on the medium with sucrose (+Si+SNP/+Si+GSNO) very strongly enhances the accumulation of free isoflavone aglycones. In +Si+SNP axes phenylalanine ammonia-lyase activity was high up to 72h. As early as at 12h in +Si+SNP axes an increase was recorded in gene expression level of the specific isoflavonoid synthesis pathway. At 24h in +Si+SNP axes a very high total antioxidant capacity dependent on the pool of fast antioxidants was noted. Post-infection generation of semiquinone radicals was lower in axes with a high level of sucrose than with a deficit.

Enhancing frequency of regeneration of somatic embryos of avocado (Persea americana Mill.) using semi-permeable cellulose acetate membranes

Regeneration of avocado via somatic embryogenesis is difficult due to poor embryo maturation, resulting in low frequencies of germination. In this study, the influence of semi-permeable cellulose acetate membranes and culture media, containing high levels of sucrose along with coconut water, on maturation and germination of somatic embryos of avocado have been evaluated. The culture of embryogenic calli on top of cellulose acetate membranes significantly increased the number of mature, white-opaque embryos that were recovered after 5 weeks of culture. These embryos showed a much more normal appearance and better quality compared with the control embryos, although the embryo size was significantly reduced. To increase the embryo size and to complete maturation, several two-step maturation treatments were tested. The culture of white-opaque somatic embryos in a modified MS medium with B5 macronutrients gelled with 10 g L−1 agar (B5m10A medium) over a 5-week period, followed by 5 additional weeks in B5m10A with 45 g L−1 sucrose and 20 % coconut water, yielded the best results, reducing the percentage of necrotic embryos and the number of calli formed. The beneficial effects of this maturation treatment were enhanced when using embryos that were pre-matured on cellulose acetate membranes. Following this two-step maturation treatment, the germination rate of the control somatic embryos, which were not cultured on cellulose membranes, was lower than 10 %, but it significantly improved when the embryos had been pre-matured on cellulose acetate membranes for 5 weeks, reaching a germination rate close to 40 %. The water availability was significantly reduced when somatic embryos were cultured on cellulose membranes, and after this pre-maturation treatment, the white-opaque embryos showed lower water potential and ABA content compared with the control embryos. These results suggest that culturing over cellulose membranes causes a controlled embryo desiccation that enhances the recovery of plants.

Mondo/ChREBP-Mlx-Regulated Transcriptional Network Is Essential for Dietary Sugar Tolerance in Drosophila

Sugars are important nutrients for many animals, but are also proposed to contribute to overnutrition-derived metabolic diseases in humans. Understanding the genetic factors governing dietary sugar tolerance therefore has profound biological and medical significance. Paralogous Mondo transcription factors ChREBP and MondoA, with their common binding partner Mlx, are key sensors of intracellular glucose flux in mammals. Here we report analysis of the in vivo function of Drosophila melanogaster Mlx and its binding partner Mondo (ChREBP) in respect to tolerance to dietary sugars. Larvae lacking mlx or having reduced mondo expression show strikingly reduced survival on a diet with moderate or high levels of sucrose, glucose, and fructose. mlx null mutants display widespread changes in lipid and phospholipid profiles, signs of amino acid catabolism, as well as strongly elevated circulating glucose levels. Systematic loss-of-function analysis of Mlx target genes reveals that circulating glucose levels and dietary sugar tolerance can be genetically uncoupled: Krüppel-like transcription factor Cabut and carbonyl detoxifying enzyme Aldehyde dehydrogenase type III are essential for dietary sugar tolerance, but display no influence on circulating glucose levels. On the other hand, Phosphofructokinase 2, a regulator of the glycolysis pathway, is needed for both dietary sugar tolerance and maintenance of circulating glucose homeostasis. Furthermore, we show evidence that fatty acid synthesis, which is a highly conserved Mondo-Mlx-regulated process, does not promote dietary sugar tolerance. In contrast, survival of larvae with reduced fatty acid synthase expression is sugar-dependent. Our data demonstrate that the transcriptional network regulated by Mondo-Mlx is a critical determinant of the healthful dietary spectrum allowing Drosophila to exploit sugar-rich nutrient sources.

The effect of carbohydrates and osmoticum on storage reserve accumulation and germination of Norway spruce somatic embryos

Somatic embryogenesis (SE) represents a useful experimental system for studying the regulatory mechanisms of embryo development. In this study, the effect of carbohydrates and osmoticum on storage reserve accumulation and germination of Norway spruce [Picea abies (L.) Karst] somatic embryos were investigated. Using time lapse photography, we monitored development from proliferation of proembryogenic masses (PEMs) to maturation of somatic embryos in two P. abies cell lines cultured on two maturation treatments. A combination of sugar assays, metabolic and proteomic analyses were used to quantify storage reserves in the mature somatic embryos. The maturation treatment containing a nonpermeating osmoticum, polyethylene glycol (PEG, 7.5%) and maltose (3%) as the carbohydrate gave significantly high maturation and low germination frequencies of somatic embryos compared to the treatment with only 3% sucrose. Somatic embryos treated with 3% sucrose contained high levels of sucrose, raffinose and late embryogenesis abundant (LEA) proteins. These compounds are known to be involved in the acquisition of desiccation tolerance during seed development and maturation. In addition the sucrose treatment significantly increased the content of starch in the somatic embryos while the maltose and PEG treatment resulted in somatic embryos with a high content of storage proteins. The high levels of sucrose, raffinose and LEA proteins in the embryos treated with 3% sucrose suggest that sucrose may improve the germination of somatic embryos by promoting the acquisition of desiccation tolerance.