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Background Peutz-Jeghers syndrome (PJS) is a rare genetic disorder characterized by the development of pigmented spots, gastrointestinal polyps and increased susceptibility to cancers. Currently, most studies have investigated intestinal microbiota through fecal microbiota, and there are few reports about mucosa-associated microbiota. It remains valuable to search for the key intestinal microbiota or abnormal metabolic pathways linked to PJS. Aim This study aimed to assess the structure and composition of mucosa-associated microbiota in patients with PJS and to explore the potential influence of intestinal microbiota disorders and metabolite changes on PJS. Methods The bacterial composition was analyzed in 13 PJS patients and 12 controls using 16S rRNA gene sequencing (Illumina MiSeq) for bacteria. Differential analyses of the intestinal microbiota were performed from the phylum to species level. Liquid chromatography-tandem mass spectrometry (LC-MS) was used to detect the differentially abundant metabolites of PJS patients and controls to identify different metabolites and metabolic biomarkers of small intestinal mucosa samples. Results High-throughput sequencing confirmed the special characteristics and biodiversity of the mucosa microflora in patients with PJS. They had lower bacterial biodiversity than controls. The abundance of intestinal mucosal microflora was significantly lower than that of fecal microflora. In addition, lipid metabolism, amino acid metabolism, carbohydrate metabolism, nucleotide metabolism and other pathways were significantly different from those of controls, which were associated with the development of the enteric nervous system, intestinal inflammation and development of tumors. Conclusion This is the first report on the mucosa-associated microbiota and metabolite profile of subjects with PJS, which may be meaningful to provide a structural basis for further research on intestinal microecology in PJS. Keywords: Peutz-Jeghers syndrome, Metabolomics, LC-MS, Mucosa-associated microbiota, Bacteria, Author(s): Sui Wang[sup.2], Guan-Jun Kou[sup.1], Xiao-Han Zhao[sup.1], Gang Huang[sup.1], Jue-Xin Wang[sup.1], Lin Tian[sup.1], Xiu-Li Zuo[sup.1], Yan-Qing Li[sup.1], Jia-Yong Wang[sup.3] and Yan-Bo Yu[sup.1] Introduction Peutz-Jeghers syndrome (PJS) is a rare genetic [...]

Introduction Soybean seeds provide major sources of oil and protein globally for human consumption and animal feed (Saha and Sultana 2008). Seed quality is determined by its composition of protein, [...], Pre-harvest soybean seeds in the field are susceptible to high temperature and humidity (HTH) stress, leading to pre-harvest seed deterioration, which will result in a reduction in grain quality, yield, and seed vigor. To understand the gene expression involved in seed deterioration response under HTH stress, in this study, we conducted an RNA-Seq analysis using two previously screened soybean cultivars with contrasting seed deterioration resistance. HTH stress induced 1081 and 357 differentially expressed genes (DEGs) in the sensitive cultivar Ningzhen No. 1 and resistant cultivar Xiangdou No. 3, respectively. The majority of DEGs in the resistant cultivar were up-regulated, while down-regulated DEGs were predominant in the sensitive cultivar. KEGG pathway analysis revealed that metabolic pathways, biosynthesis of secondary metabolites, and protein processing in endoplasmic reticulum were the predominant pathways in both cultivars during seed deterioration under HTH stress. The genes involved in photosynthesis, carbohydrate metabolism, lipid metabolism, and heat shock proteins pathways might contribute to the different response to seed deterioration under HTH treatment in the two soybean cultivars. Our study extends the knowledge of gene expression in soybean seed under HTH stress and further provides insight into the molecular mechanism of seed deterioration as well as new strategies for breeding soybean with improved seed deterioration resistance. Key words: soybean, high temperature and humidity, RNA-Seq, pre-harvest seed deterioration. Avant la recolte, les graines de soja au champ sont sensibles a un stress cause par une temperature et une humidite elevees (HTH), ce qui peut entrainer une deterioration des grains en pre-recolte, laquelle diminue la qualite des grains, le rendement et la vigueur des graines. Pour comprendre les profils d'expression genique associes a cette deterioration en reponse au stress HTH, les auteurs ont realise une etude RNA-Seq sur deux cultivars prealablement identifies comme presentant une resistance contrastee a cette deterioration. Le stress HTH a permis d'identifier, respectivement, 1081 et 357 genes a expression differentielle (DEG) chez le cultivar sensible Ningzhen No. 1 et le cultivar resistant Xiangdou No. 3. La majorite des DEG chez le cultivar resistant etaient exprimes a la hausse, tandis que les genes moins fortement exprimes etaient predominants chez le cultivar sensible. Une analyse des sentiers KEGG a revele que les 'sentiers metaboliques', la 'biosynthese des metabolites secondaires' et la 'maturation des proteines dans le reticulum endoplasmique' etaient les sentiers predominants touches lors de la deterioration des graines soumis a un stress HTH. Les genes impliques dans la photosynthese, le metabolisme des hydrates de carbone, le metabolisme des lipides et les proteines de choc thermique pourraient contribuer a la reponse differente observee entre les deux cultivars soumis a un traitement de stress HTH. Cette etude accroit les connaissances sur l'expression genique chez les graines de soja en reponse au stress HTH et fournit un eclairage sur le mecanisme moleculaire de la deterioration des graines ainsi que sur de nouvelles strategies pour selectionner des sojas dotes d'une meilleure resistance a la deterioration des graines. [Traduit par la Redaction] Mots-cles : soja, temperature et humidite elevees, RNA-Seq, deterioration des graines en pre-recolte.

Introduction Mammalian hibernators, including Richardson's ground squirrels (Urocitellus richardsonii), undergo extreme behavioural and physiological changes to survive the winter months. In preparation for the switch between summer homeothermy and winter [...], Glycerol-3-phosphate dehydrogenase (G3PDH) bridges carbohydrate and lipid metabolism by interconverting glycerol3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP). This reversible reaction converts G3P derived from triglyceride hydrolysis to DHAP that can then enter glycolysis or gluconeogenesis and, in the reverse reaction, makes G3P for use in triglyceride biosynthesis. Small hibernating mammals rely almost exclusively on triglyceride reserves as their fuel for energy production during torpor and the recovery of glycerol after lipolysis is an important source of carbohydrate over the nonfeeding winter months. G3PDH (~37 kDa) was purified from skeletal muscle of euthermic and hibernating Richardson's ground squirrels (Urocitellus richardsonii) using three column chromatography steps. Analysis of enzyme kinetic properties revealed that G3PDH from hibernator muscle had higher affinities for G3P and NAD at low (5 [degrees]C) assay temperature compared with high (21 or 37 [degrees]C) and a greater stability in the presence of denaturing agents (urea, guanidine hydrochloride) or high temperature (50 [degrees]C). Immunoblotting showed that hibernator muscle G3PDH had a higher phosphoserine content than the enzyme from euthermic controls and incubation studies showed that enzyme affinity for G3P changed significantly by stimulating endogenous protein kinases or phosphatases. Overall, this study suggests that the properties of ground squirrel muscle G3PDH are modulated by temperature and post-translational phosphorylation to alter enzyme function under euthermic versus hibernating states. Key words: glycerol-3-phosphate dehydrogenase, serine phosphorylation, muscle, Richardson's ground squirrel, hibernation. La glycerol-3-phosphate deshydrogenase (G3PDH) fait le pont entre le metabolisme des glucides et des lipides en catalysant l'interconversion du glycerol-3-phosphate (G3P) et de la dihydroxyacetone phosphate (DHAP). Cette reaction reversible convertit le G3P derive de l'hydrolyse des triglycerides en DHAP qui peut ainsi entrer dans les voies de la glycolyse ou de la gluconeogenese et, dans le cas de la reaction inverse, produit du G3P pour la biosynthese des triglycerides. Les petits mammiferes qui hibernent dependent presque exclusivement des reserves de triglycerides comme carburant pour produire de l'energie durant la periode de torpeur, et la recuperation de glycerol a la suite de la lipolyse constitue une source importante d'hydrates de carbone durant le jeune des mois d'hiver. La G3PDH (~37 kDa) a ete purifiee a partir du muscle squelettique de spermophile de Richardson (ecureuil terrestre de Richardson (Urocitellus richardsonii)) en euthermie et en hibernation, par trois etapes de chromatographie sur colonne. L'analyse des proprietes cinetiques de l'enzyme a revele que la G3PDH du muscle en hibernation presentait une affinite plus elevee envers le G3P et le NAD a faible temperature experimental (5 [degrees]C) comparativement a une temperature plus elevee (21 ou 37 [degrees]C), et une plus grande stabilite en presence d'agents denaturants (uree, chlorhydrate de guanidine) ou a haute temperature (50 [degrees]C). L'immunobuvardage montrait que la G3PDH du muscle en hibernation comportait un contenu en phosphoserine plus eleve que l'enzyme isolee du muscle controle en euthermie, et les etudes d'incubation ont montre que l'affinite de l'enzyme pour le G3P changeait de maniere significative a la suite de la stimulation des kinases et des phosphatases endogenes. Dans son ensemble, cette etude suggere que les proprietes de la G3PDH du muscle de l'ecureuil terrestre sont modulees par la temperature et la phosphorylation post-traductionnelle qui modifient la fonction de l'enzyme en fonction de l'euthermie ou de l'hibernation. [Traduit par la Redaction] Mots-cles: glycerol-3-phosphate deshydrogenase, serine phosphorylation, muscle, ecureuil terrestre de Richardson, hibernation.

The increased prevalence of overweight and obesity in the United States since approximately 1980 is temporally associated with an increase in carbohydrate intake, with no appreciable change in absolute intake of fat. Despite speculation that both carbohydrate quantity and quality have contributed significantly to excess weight gain, the relationship between carbohydrate intake and body mass index (BMI) is controversial. A review of relevant literature indicates that most epidemiologic studies show an inverse relationship between carbohydrate intake and BMI, even when controlling for potential confounders. These observational studies are supported by results from a number of dietary intervention studies wherein modest reductions in body weight were observed with an ad libitum, low-fat, high-carbohydrate diet without emphasis on energy restriction or weight loss. With few exceptions, high glycemic load is associated with lower BMI, even when adjusted for total energy intake. Data on the association between glycemic index and BMI are not as consistent, with more studies showing either no association or an inverse relationship, rather than a positive relationship. Whole-grain intake is generally inversely associated with BMI; refined grain intake is not. Because overall dietary quality tends to be higher for high-carbohydrate diets, a low-fat dietary strategy with emphasis on fiber-rich carbohydrates, particularly cereal fiber, may be beneficial for health and weight control.

Fiber type specificity of pyruvate dehydrogenase (PDH) phosphatase (PDP) was determined in fed (CON) and 48-h food-deprived (FD) rats. PDP activity and isoform protein content were determined in soleus (slow-twitch oxidative), red gastrocnemius (RG; fast-twitch oxidative glycolytic), and white gastrocnemius (WG; fast-twitch glycolytic) muscles. When normalized for mitochondrial volume, there was no difference in PDP activity between muscle types or CON and FD. When expressed per gram wet tissue weight, PDP activity was higher in RG compared with soleus and WG in both CON and FD rats. PDP activities from CON muscles were 1.48 [+ or -] 0.19, 2.68 [+ or -] 0.65, and 1.20 [+ or -] 0.33 nmol*[min.sup.-1]*g wet tissue [wt.sup.-1] in soleus, RG, and WG, respectively, and decreased in FD muscles (1.22 [+ or -] 0.22, 2.00 [+ or -] 0.57, and 0.84 [+ or -] 0.18 nmol*[min.sup.-1]*g wet tissue [wt.sup.-1]). This correlated with increased PDP2 protein, however, only in RG, as PDP2 was not detectable in soleus or WG. PDP1 protein was not responsive to food deprivation in all fiber types. In conclusion, PDP activity and protein content were higher in fast-twitch oxidative glycolytic muscles from CON and FD rats, identifying a unique inter- and intramuscular distribution. FD induced a small but significant decrease in PDP activity that was partially due to decreases in PDP2 protein. As a result, coordinate changes to PDP activity opposite to those of the other regulatory enzyme, PDH kinase, during food deprivation would maximize the inactivation of skeletal muscle PDH and enhance carbohydrate conservation during periods of limited carbohydrate supply. pyruvate dehydrogenase phosphatase-1; pyruvate dehydrogenase phosphatase-2; starvation; carbohydrate oxidation

Human studies suggest that chromium picolinate (CrPic) decreases insulin levels and improves glucose disposal in obese and type 2 diabetic populations. To evaluate whether CrPic may aid in treatment of the insulin resistance syndrome, we assessed its effects in JCR:LA-corpulent rats, a model of this syndrome. Male lean and obese hyperinsulinemic rats were randomly assigned to receive oral CrPic [80 [micro]g/(kg * d); n = 5 or 6, respectively) in water or to control conditions (water, n = 5). After 3 mo, a 120-min intraperitoneal glucose tolerance test (IPGTT) and a 30-min insulin tolerance test were performed. Obese rats administered CrPic had significantly lower fasting insulin levels (1848 [+ or -] 102 vs. 2688 [+ or -] 234 pmol/L; P < 0.001; mean [+ or -] SEM) and significantly improved glucose disappearance (P < 0.001) compared with obese controls. Glucose and insulin areas under the curve for IPGTT were significantly less for obese CrPic-treated rats than in obese controls (P < 0.001). Obese CrPic-treated rats had lower plasma total cholesterol (3.57 [+ or -] 0.28 vs. 4.11 [+ or -] 0.47 mmol/L, P < 0.05) and higher HDL cholesterol levels (1.92 [+ or -] 0.09 vs. 1.37 [+ or -] 0.36 mmol/L, P < 0.01) than obese controls. CrPic did not alter plasma glucose or cholesterol levels in lean rats. Total skeletal muscle glucose transporter (Glut)-4 did not differ among groups; however, CrPic significantly enhanced membrane-associated Glut-4 in obese rats after insulin stimulation. Thus, CrPic supplementation enhances insulin sensitivity and glucose disappearance, and improves lipids in male obese hyperinsulinemic JCR:LA-corpulent rats. KEY WORDS: * insulin * glucose * chromium * lipids * rats

Isolation, purification, and characterization of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (phe)-catalyzed products of phosphoenolpyruvate analogues and four other phosphorylated monosaccharides is presented. Data point out that the synthase catalyzed condensation of PEP analogues with E 4-P analogues follows the above facial selectivity and stereochemical course.

Results show that pyruvate kinase mutants of Bacillus subtilis do not produce acid, instead produce increased amount of carbon dioxide and reduction in growth. Data reveal that high production of phosphoenolpyruvate and glucose-6-phosphate retard bacteial growth.

Research shows that Leishmania produce lipophosphoglycans and proteophosphoglycans containing phosphosaccharide repeat units. Results with three Leishmania species demonstrate that the C-6' hydroxyl of the beta-Gal residue is involved in the substrate recognition and catalysis and a monosaccharide substituent at the C-3 position eliminates Man-P transfer during lipophosphoglycan biosynthesis.

Results reveal that HPr kinase/P-Ser-HPr phosphatase of gram-positive bacteria is a regulator protein and controls catabolic expression. Data also point out that the bifunctional enzyme may not be involved in the inducer expulsion regulatory process.

Results demonstrate that glucose 1-phosphate and glucose 6-phosphate regulate surplus carbon excretion and dissipation of excess energy in Clostridium. Data further reveal that pyruvate-acetyl coenzyme A branch points control the redox balance of the carbon metabolism.

Issues concerning the effects of carbohydrate ingestion on glycogen replenishment and subsequent short duration, high intensity exercise performance are discussed. Muscle tissue collected before and after the cycling test was analyzed for glycogen concentration, and data indicated that the decrease in performance of the placebo group did not result from a difference in glycogen concentration.

Adding arginine to a CHO supplement lessens the rate of CHO oxidation after exercise and thus may make more glucose available for muscle glycogen storage during recovery from exercise. Testing cyclists riding long enough to deplete their muscle glycogen stores and taking carbohydrate or carbohydrate-arginine supplements at specified times after exercise established these results.

A new porin, RafY, encoded by raffinose plasmid pRSD2 of Escherichia coli was identified and analyzed. Results of the study revealed that the conjugative plasmid pRSD2 conatin a raf operon that encodes a peripheral raffinose metabolic pathway in enterobacteria. Furthermore, RafY allows the diffusion of tetrasaccharide stachyose and malto dextrins through the outer membrane of E. coli.

The rate of appearance of hepatic (Ra) UDP-Glc in rats was analyzed by utilizing a novel technique involving GlcUA probes coupled with infusions of labeled galactose. Analysis of rat Ra UDP-Glc appearance base on the novel technique indicated the presence of UDP-Glc turnover in fasted rats which were increased during intravenous glucose feeding. The net deposition rate of Ra UDP-Glc was also related to glycogen deposition in the rat liver.

The effect of dietary starch type on components of 24-h energy expenditure (total, sleep, exercise) were examined in 13 hyperinsulinemic and nine control men, aged 28-58 y. Subjects consumed products containing 70% amylopectin or 70% amylose cornstarch for two 14-wk periods in a crossover design. A 10-wk period of starch replacement in the subjects' self-selected diets was followed by a 4-wk controlled feeding period at 100% maintenance energy intake; diets during the last 4 d of the controlled feeding period provided excess energy, i.e., 125% of maintenance energy. Data for insulin, glucose, 24-h energy expenditure and its components, respiratory quotient and nutrient oxidation were analyzed by ANOVA for mixed models. Although insulin and glucose responses to a starch tolerance test remained greater for hyperinsulinemic than for control subjects, both were reduced with high amylose consumption (P < 0.04). No component of energy expenditure was significantly affected by dietary starch or subject type. However, excess energy intake did increase metabolic energy expenditure (P < 0.0001). Protein oxidation increased with excess energy intake when subjects consumed the high amylopectin starch but did not increase in response to excess energy consumption when the high amylose diet was consumed, suggesting increased protein retention. The magnitude of the response in carbohydrate and fat oxidation was blunted in hyperinsulinemic subjects consuming excess levels of the amylose diet. This may be due to an improvement in overall insulin response or to a change in available substrates for oxidation resulting from microbial fermentation. J. Nutr. 126: 2120-2129, 1996. INDEXING KEY WORDS: * energy expenditure * hyperinsulinemic men * amylose starch * fuel oxidation * overfeed

The reduction in lipid of high fiber diets causes the rise in loss of bile acids with soluble fiber, the fiber has less capability of absorption and the response to insulin is lowered. The net lipid-lowering influence of fiber is decreased and metabolic effects are increased by the rise in colonic fermentation, which depend on the ratios of acetate to propionate produced by the fiber source in colon.

There is an increase in the amount of glucose and glycogen present in the gonads of the female turbot during vitellogenesis due to the increase in the use of exogenous glucose. During early vitellogenesis there is an increase in the glycolytic activity in the liver and gluconeogenesis in the kidney. In the white muscles, proteins that can be used as substrates for the synthesis of proteins or gluconeogenesis are mobilized during the maturation of the ovary.

Research conducted in dogs find that carbohydrate metabolism during exercise increases due to the reduced low arterial P(sub O2). The low arterial P(sub O2) is reduced by the increase in the percentage contribution of total carbohydrate oxidation to the total limb O2 uptake, increase in the percent contribution of LGO to LGU, and the decrease in the percentage of limb lactate with reduced arterial P(sub O2). Observed adaptation is suggested to be signaled by the sensing of reduced P(sub O2) at the muscle.

A study of the role of glucagon and insulin in enhancing glucose fluxes with reduced O2 level shows that carbohydrate metabolism is increased at reduced levels of Pa(sub O2), independent of the alterations in glucagon and insulin. An increase in 8% inspired O2 in comparison to 21% increases glucagon level by 100%, oxidation and nonoxidation process by 75-100%, and glucose disappearance by 70%. The experimental set up of the study conducted on six dogs is discussed.

A study of the association between enhanced systolic function and variations in myocardial metabolism stimulated by dichloroacetate (DCA) during myocardial ischemia reveals that DCA activates the metabolism of carbohydrates during myocardial ischemia, but does not influence systolic function. Glucose and lactate carbon-labeled tracer measurements reveal that the uptake of lactate is enhanced by DCA, while its release is lowered. Microsphere blood flow, systolic shortening and oxygen consumption do not exhibit any changes.

CARR and CARS, two protein products encoded in the carRS operon of Azospirillum brasilense, act as a response regulator and a sensor, respectively. A lesion within the carR+ gene causes carbohydrate pleiotropy, as indicated by studies with the carRS deletion clones. CARR and CARS constitute a new two-component bacterial regulating system that provides a global expression for carbohydrate pathways in A. brasilense. Sequential analyses of CARR and CARS proteins indicate that they have 236 and 352 amino acid residues, respectively.

Analysis of the cultured Trichomonas vaginalis parasitic protist in chemostats that contain maltose or glucose as energy and carbon suppliers reveals that growth rate shows a linear dependence on the maltose levels during maltose metabolism, unlike during glucose metabolism. Protein levels, growth rate and energy efficiency of the cell attain high values under glucose-limited conditions. However, slow-growing cells have less protein levels, with the maintenance energy representing half the overall carbon intake level.

A study of the influence of dietary fibers on carbohydrate digestion in wheat-, oat- and rice-based ready-to-eat breakfast cereals that are treated with alpha-amylase in vitro in eight children in the 3 to 8 year range shows that dietary fibers enhance colonic fermentation without hindering glucose availability. The level of fermented carbohydrates in oat- and wheat-based cereals exceeds that in rice-based cereals and boiled rice. All cereals produce the same level of carbohydrate digestibility.

Dephospho-CoA kinase was used to prepare 32P-labeled CoA which has a specific activity. 12,-((4-azidosalicyl) amino) dodecanoic acid which is photoreactive, its CoA derivative and the CoA derivate of 12-azidooleic acid were synthesized. The detection and characterization of lipid biosynthetic enzymes and the detection of the functioning region of these proteins can be done using acyl-CoA analogs which are photoreactive.

Carbohydrates are absorbed by gram-positive and gram-negative bacteria through the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase (PTS). Several carbohydrate-specific enzymes, enzymes II and two general proteins, namely HPr and enzyme I, comprise the carbohydrate phosphotranferase system (PTS). The PTS proteins are actively involved in chemotaxis toward PTS carbohydrates and also in carbohydrate transport. The central regulatory protein II AGlc is part of the glucose-specific PTS, restricts non-PTS uptake systems and regulates gene expression in non-phosphorylated and phosphorylated forms respectively.

The mediation of endogenous fat and glucose metabolism with respect to exercise intensity and duration was examined by employing stable isotope tracers and indirect calorimetry. The study was conducted on five trained subjects under exercise conditions of 25, 65, and 85% of maximal oxygen intake. Plasma glucose consumption, muscle glycogen consumption and muscle glycogen oxidation were augmented in correlation to exercise intensities. It was concluded that the regulation of lipid metabolisms is more complex than carbohydrate metabolism regulation.

Computer stochastic dynamics simulations were used to study the formation of extended peptide chain conformations in mucins and other O-glycosylated glycoproteins. It was found that removing carbohydrate from the glycopeptide AAA(NeuNAc 2-6 GalNAc)-T(NeuNAc 2-6 GalNAc)-TAAA causes end-to-end distance and radius of gyration to be reduced by 32% and 33%, respectively. Results also revealed the presence of two peptide-carbohydrate hydrogen bonds that might have an effect on O-linked GalNAc orientation. Short-range intramolecular steric and hydrogen bond interactions caused by glocosylated residue clustering are believed to be responsible for the observed mucin peptide chain dimensions.

Each perennial woody plant is a highly integrated system of competing carbohydrate sinks (utilization sites). Internal competition for carbohydrates is shown by changes in rates of carbohydrate movement from sources to sinks and reversals in direction of carbohydrate transport as the relative sink strengths of various organs change. Most carbohydrates are produced in foliage leaves but some are synthesized in cotyledons, hypocotyls, buds, twigs, stems, flowers, fruits, and strobili. Although the bulk of the carbohydrate pool moves to sinks through the phloem, some carbohydrates are obtained by sinks from the xylem sap. Sugars are actively accumulated in the phloem and move passively to sinks along a concentration gradient. The dry weight of a mature woody plant represents only a small proportion of the photosynthate it produced. This discrepancy results not only from consumption of plant tissues by herbivores and shedding of plant parts, but also from depletion of carbohydrates by respiration, leaching, exudation, secretion, translocation to other plants through root grafts and mycorrhizae and losses to parasites. Large spatial and temporal variations occur in the use of reserve- and currently produced carbohydrates in metabolism and growth of shoots, stems, roots, and reproductive structures. A portion of the carbohydrate pool is diverted for production of chemicals involved in defense against fungi, herbivores, and competing plants. Woody plants accumulate carbohydrates during periods of excess production and deplete carbohydrates when the rate of utilization exceeds the rate of production. Stored carbohydrates play an important role in metabolism, growth, defense, cold hardiness, and postponement or prevention of plant mortality.