Distribution Of Carbohydrates Research Articles

Maize Carbohydrate partitioning defective1 impacts carbohydrate distribution, callose accumulation, and phloem function.

Plants synthesize carbohydrates in photosynthetic tissues, with the majority of plants transporting sucrose to non-photosynthetic tissues to sustain growth and development. While the anatomical, biochemical, and physiological processes regulating sucrose long-distance transport are well characterized, little is known concerning the genes controlling whole-plant carbohydrate partitioning. To identify loci influencing carbon export from leaves, we screened mutagenized maize plants for phenotypes associated with reduced carbohydrate transport, including chlorosis and excessive starch and soluble sugars in leaves. Carbohydrate partitioning defective1 (Cpd1) was identified as a semi-dominant mutant exhibiting these phenotypes. Phloem transport experiments suggested that the hyperaccumulation of starch and soluble sugars in the Cpd1/+ mutant leaves was due to inhibited sucrose export. Interestingly, ectopic callose deposits were observed in the phloem of mutant leaves, and probably underlie the decreased transport. In addition to the carbohydrate hyperaccumulation phenotype, Cpd1/+ mutants overaccumulate benzoxazinoid defense compounds and exhibit increased tolerance when attacked by aphids. However, double mutant studies between Cpd1/+ and benzoxazinoid-less plants indicate that the ectopic callose and carbon hyperaccumulation are independent of benzoxazinoid production. Based on the formation of callose occlusions in the developing phloem, we hypothesize that the cpd1 gene functions early in phloem development, thereby impacting whole-plant carbohydrate partitioning.

Strigolactones restore vegetative and reproductive developments in Huanglongbing (HLB) affected, greenhouse-grown citrus trees by modulating carbohydrate distribution

Abstract Two-year-old greenhouse-grown Huanglongbing (HLB)-affected and healthy ‘Hamlin’ sweet orange (Citrus sinensis L. Osbeck) trees were spray treated with 10 μM strigolactone (SL) during the floral induction period (November 2016 and January 2017), and the flowering and fruit-setting period (April and June of 2017). Trees were grouped in four treatments: SL-treated HLB-affected trees; untreated HLB-affected trees; SL-treated healthy trees, and healthy control trees. Strigolactone application on HLB-affected trees during floral induction accelerated and augmented reproductive growth by inducing a 2.3-fold increase in flower bearing branches and an average of 2.6-fold increase in flowers per tree within two months from application. On the contrary, the same trees produced 31% less vegetative branches, 55% less flower bearing branches and 85% fewer flowers than HLB trees during the spring flush (April 2017). For the entire season, the number of fruit was higher in HLB + SL trees compared to untreated HLB-affected trees. Strigolactone application on healthy trees increased sucrose and starch content in mature leaves by 26% and 166%, respectively, with a 47% increase in the number of flowers compared to untreated trees. Strigolactone application during the flowering and fruit-setting period induced additional summer flush. The results of iodine staining and analytical observations demonstrated a decline in starch content in leaves and an increase in roots of SL-treated HLB-affected trees. We conclude that strigolactone ameliorates the effect of HLB by balancing vegetative and reproductive developmental response in HLB-affected citrus trees through the partitioning of stored carbohydrate.

Seeing is believing: Insights from synchrotron infrared mapping for membrane fouling in osmotic membrane bioreactors

We employed synchrotron infrared (IR) mapping to resolve forward osmosis (FO) membrane fouling in osmotic membrane bioreactor (OMBR). Synchrotron IR mapping offers a unique perspective to elucidate the fouling mechanisms and associated consequences in OMBR operation. We demonstrated the spatial distribution and relative intensity of carbohydrate and protein longitudinally along of the fouled FO membrane at the conclusion of OMBR operation. Both transmission and attenuated total reflection (ATR) modes were used to map the cross-section and surface of the fouled FO membrane. Micro X-ray computed tomography revealed patchy, “sand-dune” features on the membrane surface at the conclusion of OMBR operation. Synchrotron IR-ATR mapping demonstrated that the development of membrane fouling layer in OMBR operation was initiated by polysaccharide-like carbohydrate, followed by layering with protein-like substance, resulting in a characteristic “sand-dune” three dimensional feature. Synchrotron FTIR mapping shed light on foulant occurrence and accumulation in the draw solution. Strong penetration of protein-like substance into membrane matrix was visualised, resulting the detection of protein adsorption in the region of membrane supporting layer.

Sucrose is involved in the regulation of iron deficiency responses in rice (Oryza sativa L.)

Sucrose signaling pathways were rapidly induced in response to early iron deficiency in rice plants, and the change of sucrose contents in plants was essential for the activation of iron deficiency responses. Sucrose is the main product of photosynthesis in plants, and it functions not only as an energy metabolite but also a signal molecule. However, a few studies have examined the involvement of sucrose in mediating iron deficiency responses in rice. In this study, we found that the decrease in photosynthesis and total chlorophyll concentration (SPAD values) in leaves occurred at a very early stage under iron deficiency. In addition, the sucrose was increased in leaves but decreased in roots of rice plants under iron deficiency, and also the sucrose transporter (SUT) encoded genes' expression levels in leaves were all inhibited, including OsSUT1, OsSUT2, OsSUT3, OsSUT4, and OsSUT5. The carbohydrate distribution was changed under iron deficiency and sucrose might be involved in the iron deficiency responses of rice plants. Furthermore, exogenous application of sucrose or dark treatment experiments were used to test the hypothesis; we found that the increased endogenous sucrose would cause the repression of iron acquisition-related genes in roots, while further stimulated iron transport-related genes in leaves. Compared to the exogenous application of sucrose, the dark treatment had the opposite effects. All the above results highlighted the important role of sucrose in regulating the responses of rice plants to iron deficiency.

Whole-tree distribution and temporal variation of non-structural carbohydrates in broadleaf evergreen trees.

Non-structural carbohydrates (NSCs) form a fundamental yet poorly quantified carbon pool in trees. Studies of NSC seasonality in forest trees have seldom measured whole-tree NSC stocks and allocation among organs, and are not representative of all tree functional types. Non-structural carbohydrate research has primarily focussed on broadleaf deciduous and coniferous evergreen trees with distinct growing seasons, while broadleaf evergreen trees remain under-studied despite their different growth phenology. We measured whole-tree NSC allocation and temporal variation in Eucalyptus obliqua L'Hér., a broadleaf evergreen tree species typically occurring in mixed-age temperate forests, which has year-round growth and the capacity to resprout after fire. Our overarching objective was to improve the empirical basis for understanding the functional importance of NSC allocation and stock changes at the tree- and organ-level in this tree functional type. Starch was the principal storage carbohydrate and was primarily stored in the stem and roots of young (14-year-old) trees rather than the lignotuber, which did not appear to be a specialized starch storage organ. Whole-tree NSC stocks were depleted during spring and summer due to significant decreases in starch mass in the roots and stem, seemingly to support root and crown growth but potentially exacerbated by water stress in summer. Seasonality of stem NSCs differed between young and mature trees, and was not synchronized with stem basal area increments in mature trees. Our results suggest that the relative magnitude of seasonal NSC stock changes could vary with tree growth stage, and that the main drivers of NSC fluctuations in broadleaf evergreen trees in temperate biomes could be periodic disturbances such as summer drought and fire, rather than growth phenology. These results have implications for understanding post-fire tree recovery via resprouting, and for incorporating NSC pools into carbon models of mixed-age forests.

Morphology, Carbohydrate Distribution, Gene Expression, and Enzymatic Activities Related to Cell Wall Hydrolysis in Four Barley Varieties during Simulated Malting.

Many biological processes, such as cell wall hydrolysis and the mobilisation of nutrient reserves from the starchy endosperm, require stringent regulation to successfully malt barley (Hordeum vulgare) grain in an industrial context. Much of the accumulated knowledge defining these events has been collected from individual, unrelated experiments, and data have often been extrapolated from Petri dish germination, rather than malting, experiments. Here, we present comprehensive morphological, biochemical, and transcript data from a simulated malt batch of the three elite malting cultivars Admiral, Navigator, and Flagship, and the feed cultivar Keel. Activities of lytic enzymes implicated in cell wall and starch depolymerisation in germinated grain have been measured, and transcript data for published cell wall hydrolytic genes have been provided. It was notable that Flagship and Keel exhibited generally similar patterns of enzyme and transcript expression, but exhibited a few key differences that may partially explain Flagship's superior malting qualities. Admiral and Navigator also showed matching expression patterns for these genes and enzymes, but the patterns differed from those of Flagship and Keel, despite Admiral and Navigator having Keel as a common ancestor. Overall (1,3;1,4)-β-glucanase activity differed between cultivars, with lower enzyme levels and concomitantly higher amounts of (1,3;1,4)-β-glucan in the feed variety, Keel, at the end of malting. Transcript levels of the gene encoding (1,3;1,4)-β-glucanase isoenzyme EI were almost three times higher than those encoding isoenzyme EII, suggesting a previously unrecognised importance for isoenzyme EI during malting. Careful morphological examination showed that scutellum epithelial cells in mature dry grain are elongated but expand no further as malting progresses, in contrast to equivalent cells in other cereals, perhaps demonstrating a morphological change in this critical organ over generations of breeding selection. Fluorescent immuno-histochemical labelling revealed the presence of pectin in the nucellus and, for the first time, significant amounts of callose throughout the starchy endosperm of mature grain.

Grapevine tissues and phenology differentially affect soluble carbohydrates determination by capillary electrophoresis

Soluble carbohydrates distribution depends on plant physiology and, among other important factors, determines fruit yield and quality. In plant biology, the analysis of sugars is useful for many purposes, including metabolic studies. Capillary electrophoresis (CE) proved to be a powerful green separation technique with minimal sample preparation, even in complex plant tissues, that can provide high-resolution efficiency. Matrix effect refers to alterations in the analytical response caused by components of a sample other than the analyte of interest. Thus, the assessment and reduction of the matrix factor is fundamental for metabolic studies in different matrices. The present study evaluated the source and levels of matrix effects in the determination of most abundant sugars in grapevine tissues (mature and young leaves, berries and roots) at two phenological growth stages. Sucrose was the sugar that showed the least matrix effects, while fructose was the most affected analyte. Based on plant tissues, young leaves presented the smaller matrix effects, irrespectively of the phenology. These changes may be attributed to considerable differences at chemical composition of grapevine tissues with plant development. Therefore, matrix effect should be an important concern for plant metabolomics.

Suppression of cucumber stachyose synthase gene (CsSTS) inhibits phloem loading and reduces low temperature stress tolerance

Stachyose is the main transporting sugar in phloem of Raffinose family oligosaccharides-transporting species. Stachyose synthase (STS) is a key enzyme for stachyose biosynthesis, but the gene encoding STS is poorly characterized in cucumber (Cucumis sativus L.), which is a model plant for studying stachyose metabolism and phloem function. In this research, stachyose synthase gene (CsSTS) from cucumber was isolated and its physiological functions were analyzed. CsSTS expressed mainly in the phloem of the minor veins in mature leaves and localized to companion cells. Reverse genetics with CsSTS RNAi lines revealed obviously reductions in STS activity and stachyose content along with a small amount of starch accumulation in leaves, suggesting that CsSTS is involved in phloem loading of cucumber leaves. After 6 °C low temperature stress, malondialdehyde content and electrical conductivity increased, especially in CsSTS-RNAi plants. But CsSTS expression was up-regulated, STS activity and stachyose level increased, the activities of reactive-oxygen-scavenging enzyme in cucumber seedlings improved significantly and starch accumulation reduced, especially in CsSTS-OE lines. These results demonstrate clearly that CsSTS is involved in phloem loading, carbohydrate distribution and tolerance of cucumber seedlings to low temperature stress.

Implications of Seasonal Canopy Management and Growth Compensation in Grapevine

The effect of eight seasonal canopy management treatments on yield and growth compensation of a vertically trellised Vitis vinifera L. cv. Sauvignon blanc/110 Richter vineyard was investigated. East-West orientated rows were spaced 2.75 x 1.5 m. Spurs were spaced 15 cm apart. Intensive micro-irrigation was applied. Canopy management comprised better accommodation of foliage on the trellising system and different means of reducing foliage during the berry set to pea berry size period of the growth season. Combinations of shoot positioningsuckering-topping and shoot positioning-suckering-topping-leaf removal resulted in the highest yields; substituting leaf removal with lateral (secondary shoot) removal noticeably decreased yields. No canopy management resulted in the lowest yields. Based on production (and labour), lateral shoot removal cannot be considered an economically viable canopy management practice. Significant compensatory growth was induced by the removal of lateral shoots. That would have impacted on the distribution of carbohydrates and probably counterbalanced the positive effects of an improved microclimate and related. reactions. Lateral removal reduced bunch development compared to treatments that included leaf removal instead. Yield differences between treatments showed no obvious relationship with fertility or budding. Neither bunch rot nor soluble solid accumulation played a role in the yield reduction found with lateral removal. Total hexose content in the berries at ripeness was, however, reduced by lateral removal, decreasing further the earlier lateral removal was applied. For the treatments where no laterals were removed, lateral leaves made the highest contribution to the total sugar content of the leafy part of the canopy. The ratio between the total output of the main shoot leaves and that of the lateral shoots was reversed when laterals were removed. Sugar content of leaves on main shoots of lateral removal treatments complied with the compensation theory of source:sink relationship. Apparently, shading had a pronounced effect on the total carbohydrate content of non-treated canopies. Although root starch content was not affected by lateral removal during the study period, root density was decreased, indicating limited root development. A positive relationship between root density and yield was found. Although the presence of particularly medium and small leaves and therefore the contribution of these leaves to yield was reduced by lateral removal, the total leaf area/g fruit was never less than the generally accepted norm of 12 cm2• The results indicated that available leaf area (even when well-exposed) cannot generally be accepted as the norm, but that the composition of the leaf area should be taken into account, as it has a critical role in the efficiency of the canopy and the nourishing of the bunches. Ratios of main shoot leaf area to lateral shoot leaf area as well as practical canopy composition criteria are presented. Results are also argued as to the role of hormonal activity in growth compensation and trigger mechanisms. The results provide new perspectives on existing canopy composition criteria and implications of growth compensation. The study clearly indicates the beneficial effects of correct seasonal canopy management.

Carbohydrates and gibberellins relationship in potato tuberization

Potato represents the third most important crop worldwide and therefore to understand regulations of tuber onset is crucial from both theoretical and practical points of view. Photosynthesis and related carbohydrate status along with phytohormone balance belong to the essential factors in regulation of plant development including storage organ formation. In our work we used potato (Solanum tuberosum) cv. Lada and its spontaneously tuberizing mutant (ST plants) grown in vitro under low carbohydrate availability (non-inductive conditions). Small plant phenotype and readiness to tuberization of ST plants was, however, not accompanied by lower gibberellins levels, as determined by UHPLC–MS/MS. Therefore, we focused on the other inducing factor, carbohydrate status. Using HPLC, we followed changes in carbohydrate distribution under mixotrophic (2.5% sucrose in medium) and photoautotrophic conditions (no sucrose addition and higher gas and light availability) and observed changes in soluble carbohydrate allocation and starch deposition, favouring basal stem part in mutants. In addition, the determination of tuber-inducing marker gene expressions revealed increased levels of StSP6A in ST leaves. Collectively these data point towards the possibility of two parallel cross-talking pathways (carbohydrate − and gibberellin- dependent ones) with the power of both to outcompete the other one when its signal is for some reason extraordinary strong.

The effect of diurnal distribution of carbohydrates and fat on glycaemic control in humans: a randomized controlled trial

Diurnal carbohydrate and fat distribution modulates glycaemic control in rodents. In humans, the optimal timing of both macronutrients and its effects on glycaemic control after prolonged consumption are not studied in detail. In this cross-over trial, 29 non-obese men were randomized to two four-week diets: (1) carbohydrate-rich meals until 13.30 and fat-rich meals between 16.30 and 22.00 (HC/HF) versus (2) inverse sequence of meals (HF/HC). After each trial period two meal tolerance tests were performed, at 09.00 and 15.40, respectively, according to the previous intervention. On the HF/HC diet, whole-day glucose level was increased by 7.9% (p = 0.026) in subjects with impaired fasting glucose and/or impaired glucose tolerance (IFG/IGT, n = 11), and GLP-1 by 10.2% (p = 0.041) in normal glucose-tolerant subjects (NGT, n = 18). Diet effects on fasting GLP-1 (p = 0.009) and PYY (p = 0.034) levels were observed in IFG/IGT, but not in NGT. Afternoon decline of glucose tolerance was more pronounced in IFG/IGT and associated with a stronger decrease of postprandial GLP-1 and PYY levels, but not with changes of cortisol rhythm. In conclusion, the HF/HC diet shows an unfavourable effect on glycaemic control in IFG/IGT, but not in NGT subjects. Consequently, large, carbohydrate-rich dinners should be avoided, primarily by subjects with impaired glucose metabolism.

Carbohydrate distribution during berry ripening of potted grapevines: Impact of water availability and leaf-to-fruit ratio

Insufficient leaf photoassimilation could allow mobilized carbohydrate reserves to contribute to berry sugar accumulation. However, the extent of this contribution during rapid and slow berry sugar accumulation is undefined. The potential effect of leaf-to-fruit ratio and water availability on carbohydrate reserve distribution in potted Tempranillo grapevines was examined during berry maturation. Within each leaf-to-fruit ratio treatment (full and 50% leaves), vines were grown under full or 50% reduced irrigation regimes. Dry biomass development, and the starch and soluble sugar concentrations were determined in the roots, trunks, stems and leaves. Berry sugar and anthocyanin accumulation were also assessed. Under full irrigation, no starch remobilization from roots was observed, regardless of the leaf-to-fruit ratio. Under reduced water supply, starch remobilization from roots was concurrent with rapid berry sugar accumulation, especially in grapevines with low leaf-to-fruit ratio. Soluble sugar accumulation coincided with starch depletion in the roots of grapevines under reduced water availability. When berry sugar accumulation slowed, an increase in carbohydrates was observed in the roots. Sustained water constraints during rapid berry sugar accumulation resulted in a forced reliance on stored carbohydrates to support berry sugar accumulation, but did not significantly alter the tempo of berry sugar and anthocyanin accumulation. A reduced leaf-to-fruit ratio intensified the reliance of fruit sugar accumulation on stored carbohydrates. Besides the importance of post-harvest carbohydrate reserve replenishment when root carbohydrate reserves are depleted during berry maturation, the reserves are also refilled during maturation when berry sugar accumulation slows. This study showed distinctly that root carbohydrate replenishment could already start a few weeks before harvest, and this replenishment could be important when the post-harvest carbon assimilation period is ineffective.

Are the distributions of carbohydrates, meals and snacks associated with blood glucose control in women with gestational diabetes? A pilot study using myfood24 dietary assessment tool

Are the distributions of carbohydrates, meals and snacks associated with blood glucose control in women with gestational diabetes? A pilot study using myfood24 dietary assessment tool - Volume 76 Issue OCE4

Heat stress in grain legumes during reproductive and grain-filling phases

Thermal stress during reproductive development and grain-filling phases is a serious threat to the quality and productivity of grain legumes. The optimum temperature range for grain legume crops is 10−36°C, above which severe losses in grain yield can occur. Various climatic models have simulated that the temperature near the earth’s surface will increase (by up to 4°C) by the end of this century, which will intensify the chances of heat stress in crop plants. The magnitude of damage or injury posed by a high-temperature stress mainly depends on the defence response of the crop and the specific growth stage of the crop at the time of exposure to the high temperature. Heat stress affects grain development in grain legumes because it disintegrates the tapetum layer, which reduces nutrient supply to microspores leading to premature anther dehiscence; hampers the synthesis and distribution of carbohydrates to grain, curtailing the grain-filling duration leading to low grain weight; induces poor pod development and fractured embryos; all of which ultimately reduce grain yield. The most prominent effects of heat stress include a substantial reduction in net photosynthetic rate, disintegration of photosynthetic apparatus and increased leaf senescence. To curb the catastrophic effect of heat stress, it is important to improve heat tolerance in grain legumes through improved breeding and genetic engineering tools and crop management strategies. In this review, we discuss the impact of heat stress on leaf senescence, photosynthetic machinery, assimilate translocation, water relations, grain quality and development processes. Furthermore, innovative breeding, genetic, molecular and management strategies are discussed to improve the tolerance against heat stress in grain legumes.

Sectorial land snail damage to the lichen Argopsis friesiana could be explained by metabolite profiles

Notodiscus hookeri is the only native land snail of the sub-Antarctic present in Crozet Archipelago. Two shell ecophenotypes co-exist on Possession Island and feed exclusively on lichens [1] that are symbiotic organisms widely distributed in sub-Antarctic islands. To improve our understanding of lichen-snail trophic interactions, the endemic tripartite lichen Argopsis friesiana was selected. The snail belonging to the organic ecophenotype occurs sympatrically with A. friesiana. Profiling and quantification of the major secondary metabolites in the whole lichen were carried out by LC-DAD-MS. Two main compounds were identified, the depside atranorin (8.2 mg g-1 DM) and the depsidone argopsin. Besides, a screening of primary metabolites was carried out to determine which compounds could be useful for the snail energetic demands. Glutamate, glutamine, gamma-aminobutyric acid and alpha-alanine were the main amino acids found in the lichen in low concentrations (0.4 mg·g-1 DM). Carbohydrates, including arabitol (10.2 mg g-1), mannitol (4.0.10-4 mg g-1) and sucrose (3.0.10-4 mg g-1), were also identified. In cultivation, N. hookeri snails were fed with fructified thalli of A. friesiana. Snails (n = 20) ate the podetia cortex and phyllocladia but they clearly avoided apothecia, the reproductive organs. This sectorial damage of the lichen by the snail suggested a differential distribution of the metabolites. Therefore, a profiling of secondary compounds was performed by Direct Analysis in Real Time – Mass Spectroscopy (DART-MS) [2] on each morphological part of the lichen (phyllocladia, apothecia, podetia and cephalodia). The identification and distribution of secondary metabolites, fatty acids, amino acids and carbohydrates should help us to determine whether metabolites affect snail feeding choice and which of them could be involved.

Integrating Physiology and Architecture in Models of Fruit Expansion.

Architectural properties of a fruit, such as its shape, vascular patterns, and skin morphology, play a significant role in determining the distributions of water, carbohydrates, and nutrients inside the fruit. Understanding the impact of these properties on fruit quality is difficult because they develop over time and are highly dependent on both genetic and environmental controls. We present a 3D functional-structural fruit model that can be used to investigate effects of the principle architectural properties on fruit quality. We use a three step modeling pipeline in the OpenAlea platform: (1) creating a 3D volumetric mesh representation of the internal and external fruit structure, (2) generating a complex network of vasculature that is embedded within this mesh, and (3) integrating aspects of the fruit's function, such as water and dry matter transport, with the fruit's structure. We restrict our approach to the phase where fruit growth is mostly due to cell expansion and the fruit has already differentiated into different tissue types. We show how fruit shape affects vascular patterns and, as a consequence, the distribution of sugar/water in tomato fruit. Furthermore, we show that strong interaction between tomato fruit shape and vessel density induces, independently of size, an important and contrasted gradient of water supply from the pedicel to the blossom end of the fruit. We also demonstrate how skin morphology related to microcracking distribution affects the distribution of water and sugars inside nectarine fruit. Our results show that such a generic model permits detailed studies of various, unexplored architectural features affecting fruit quality development.

Effect of carbohydrate restriction in the first meal after an overnight fast on glycemic control in people with type 2 diabetes: a randomized trial

People with type 2 diabetes are advised to consume an even meal distribution of carbohydrate. Whether this distribution is optimal is unknown. Our objective was to show that omitting carbohydrate in the first meal after a fast would lead to an augmented lunch response. Two diets of 1-d duration that differed only in the breakfast-meal composition (carbohydrate or no carbohydrate) were consumed on sequential days in a randomized crossover study. The procedure was repeated in the alternate order 1 wk later. Blood glucose concentrations were tested with the use of continuous glucose monitoring. The primary endpoints were the percentage of time spent with a blood glucose concentration >10 mmol/L (%T >10) and peak blood glucose (Gmax). The following 45 adults with type 2 diabetes were recruited: subjects with glycated hemoglobin (HbA1c) ≤7% and subjects with HbA1c ≥8%. Twenty-eight adults completed the study. The daily Gmax was significantly lower after the no-carbohydrate breakfast than after the carbohydrate breakfast (11.0 ± 0.4 and 12.1 ± 0.4 mmol/L, respectively; P = 0.003) whereas the %T >10 throughout the day was a nonsignificant 22% less after the no-carbohydrate breakfast than after the carbohydrate breakfast (13% ± 10% compared with 10% ± 8%; P = 0.09). Gmax over 5 h after breakfast was significantly lower after the no-carbohydrate meal (by 1.9 ± 0.4 mmol/L; P < 0.001), and the %T >10 was lower after the no-carbohydrate meal than after the carbohydrate meal (11% ± 3% compared with 26% ± 4%, respectively; P < 0.001). The withholding of carbohydrate in the first meal results in significantly decreased Gmax after the meal, but the lunch response is not affected. Overall daily control is not significantly improved. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTRN12609000331235.

Variation in Carbohydrates between Cancer and Normal Cell Membranes Revealed by Super-Resolution Fluorescence Imaging.

Carbohydrate alterations on cell membranes are associated with various cancer processes, including tumorigenesis, malignant transformation, and tumor dissemination. However, variations in the distributions of cancer‐associated carbohydrates are unclear at the molecular level. Herein, direct stochastic optical reconstruction microscopy is used to reveal that seven major types of carbohydrates tended to form obvious clusters on cancer cell membranes compared with normal cell membranes (both cultured and primary cells), and most types of carbohydrates present a similar distributed characteristic on various cancer cells (e.g., HeLa and Os‐Rc‐2 cells). Significantly, sialic acid is found to distribute in larger‐sized clusters with a higher cluster coverage percentage on various cancer cells than normal cells. These findings on the aberrant distributions of cancer‐associated carbohydrates can potentially serve as novel diagnostic and therapeutic targets, as well as making a contribution to clarify how abnormal glycosylations of membrane glycoconjugates participate in tumorigenesis and metastasis.

N-acetyl Glucosamine Distribution and Mitochondrial Activity of Tumor Cell Exposed to Photodynamic Therapy.

The use of lectins can play an important role for tracking modification on cell surface components, since lectins can be easily complexed with radioisotopes, biotin or fluorescein, facilitating the evaluation of carbohydrates distribution in the cell and mitochondrial activity. The aim of this study was to evaluate photodynamic therapy effects on indirect distribution of N-acetyl-glucosamine terminal glycoproteins, in human laryngeal carcinoma HEp-2 cell line surface, using lectin wheat germ agglutinin (WGA) and on mitochondrial activity, for the same cell line, using MitoTracker. The photosensitizer Aluminum Phthalocyanine Tetrasulfonate (AlPcS4) was administrated at 10μM/mL, followed by an incubation period for its accumulation in the tumor cells, which were irradiated with laser diode λ=685nm and energy density of 4.5J/cm2. Our results indicated that, after Photodynamic Therapy (PDT), it was observed N-acetyl glucosamine terminal glycoprotein expression and mitochondrial O2 production, compared to the control group. Based on these results, we suggest that PDT influences the O2 mitochondrial production and the presence of surface glycoproteins N-acetyl glucosamine terminals.

Daily Distribution of Carbohydrate, Protein and Fat Intake in Elite Youth Academy Soccer Players Over a 7-Day Training Period.

While traditional approaches to dietary analysis in athletes have focused on total daily energy and macronutrient intake, it is now thought that daily distribution of these parameters can also influence training adaptations. Using 7-day food diaries, we quantified the total daily macronutrient intake and distribution in elite youth soccer players from the English Premier League in U18 (n = 13), U15/16 (n = 25) and U13/14 squads (n = 21). Total energy (43.1 ± 10.3, 32.6 ± 7.9, 28.1 ± 6.8 kcal·kg-1·day-1), CHO (6 ± 1.2, 4.7 ± 1.4, 3.2 ± 1.3 g·kg-1·day-1) and fat (1.3 ± 0.5, 0.9 ± 0.3, 0.9 ± 0.3 g·kg-1·day-1) intake exhibited hierarchical differences (p < .05) such that U13/14 > U15/16 > U18. In addition, CHO intake in U18s was lower (p < .05) at breakfast, dinner and snacks when compared with both squads but no differences were apparent at lunch. Furthermore, the U15/16s reported lower relative daily protein intake than the U13/14s and U18s (1.6 ± 0.3 vs. 2.2 ± 0.5, 2.0 ± 0.3 g·kg-1). A skewed distribution (p < .05) of daily protein intake was observed in all squads, with a hierarchical order of dinner (~0.6 g·kg-1) > lunch (~0.5 g·kg-1) > breakfast (~0.3 g·kg-1). We conclude elite youth soccer players do not meet current CHO guidelines. Although daily protein targets are achieved, we report a skewed daily distribution in all ages such that dinner > lunch > breakfast. Our data suggest that dietary advice for elite youth players should focus on both total daily macronutrient intake and optimal daily distribution patterns.