• Journal of Plant Biotechnology
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• v.2 no.1
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• pp.13-19
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• 2000

Carbohydrates serve three different principal functions in the metabolism of plants. They are the primary products of energy fixation, they are important transport metabolites, and they are deposited as structural or storage compounds. Modification of carbohydrate metabolism therefore covers approaches to modify yield, to change sink/source relationships and thereby alter the ratio of harvestable material, and to improve the quality of crop plants. The scope of this article is to summarize research done at the Max-Planck-Institute related to the first two fields and to present in some detail what we learned, when we established a new carbohydrate storage form in potato.

• Journal of the Korean Society of Food Culture
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• v.22 no.1
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• pp.157-165
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• 2007

This study was designed to evaluate the effects of fructose(F) or sucrose(S) and guar gum intake on carbohydrate and lipid metabolism in 15-week-old male Goto-Kakizaki(GK) rats. Fifty rats were randomly assigned to 5 groups which were different in carbohydrate(25% of carbohydrate) and fiber(5% w/w) sources. The carbohydrate(CHO) sources of each group were comstarch(control group, 100% of CHO), fructose with cellulose(F), fructose with guar gum(FG), sucrose with cellulose(S), and sucrose with guar gum(SG). Each group was fed exterimental diet for 4 weeks. We measured food intake, body weight gain, adipose tissues weight and organs weight. We conducted oral glucose tolerance test(OGTT) and measured plasma insulin concentration to examine carbohydrate metabolism. To evaluate lipid metabolism, we measured the lipid profile of plasma, liver and feces. Food intake and weight gain of FG or SG groups tended to be less than those of F or S groups. Perirenal and epididymal fat pad weights of SG group were significantly lower than those of S group and those of FG group tended to be lower than those of F group. In OGTT, blood glucose values of F or S groups were significantly higher than those of C group, and FG or SG groups tended to be lower than those of F or S groups during the experimental time. The area under the curve(AUC) of C group was significantly highest among the groups, AUC and plasma insulin concentration of FG or SG groups tended to be lower than those of F or S groups. Plasma and hepatic triglyceride (TG) of FG and SG groups were significantly lower than those of F and S groups, plasma and hepatic total lipid(TL) and total cholesterol(TC) of FG and SG groups tended to be lower than those of F and S groups. Fecal TL, TG and TC of FG or SG groups tended to be higher than those of F and S groups. In conclusion, intake of guar gum should improve carbohydrate and lipid metabolism in partial substitution of fructose or sucrose for cornstarch in GK rats.

• Journal of Nutrition and Health
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• v.20 no.2
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• pp.135-144
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• 1987

This study was carried out to investigate the effect of dietray carbohydrate level on the lipid and Ca metabolism, and on immune response in the process of aging. Sprag\ulcornerue - Dawley male rats of 12 months of age were fed either high carbohydrate or low carbohydrate diet for 9 months. With increasing age from 12 months to 21 months, there was no significant increase in body weight, however, the epididymal fat pat weight and total serum lipid tend to become higher, and the inorganic/organic matterratio in bone tends to become lower. This suggests that body fat accumulation increase and bone mass decrease with age. Rats fed low carbohydrate diet showed the higher epididymal fat pat weight, and the lower Ca content in femur and scapular compared to high carbohydrate diet fed rats. The immune response was also lower in low carbohydrate diet group judged by the lower thymus and spleen index and by the lower response to PHA and ConA stimulation. The results of this study suggests that the dietary level of carbohydrate and fat may play an important role in the process of aging. It could be recommended to practice high carbohydrate -low fat diet for the elderly to reduce the risk of degenerative diseases.

• Korean Journal of Microbiology
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• v.6 no.2
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• pp.41-53
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• 1968

Studies on the carbohydrate metabolism of yeast as influenced by gamma-irradiation from cobalt-60 have been carried, then the mechanisms of radiation effect on respiration and fermentation were discussed under considerations of permeable changes of irradiated cell membrane. The cells of baker's yeast (Saccharomyces cerevisiae) which had been gamma-irradiated of 240 k.r. doses for an hour, then were put into aerobic oxidation and anaerobic fermentation without substrate. Total and fractionated carbohydrates of irradiated yeast cells were determined by calorimetric method with anthrone and orcinol reagents, the amounts of total carbohydrate, trehalose, RNA-ribose, PCA-soluble glycogen, alkali-soluble glycogen, acetic acid-soluble glycogen, mannan and glucan were determined according to the course of aerobic oxidation and anaerobic fermentation. It is found that the carbohydrates of irradiated cells leak out and amount of the losses teaches eleven times more than that of control, the volume of losses are seems to be replaced by water, it can be suggested the damage of gamma-irradiation occurs in the site of passive transport of cell membrane. The endogeneous aerobic respiration of irradiated cells are increased much more than control, the synthesis of reserve glycogen, glucan and RNA-ribose promoted much more than control. The anaerobic fermentation of irradiated cells are also increased than that of control, but the breakdown of carbohydrate is less than endogeneous respiration of irradiated cells. The synthetic rate is also less than that of aerobic oxidation. In irradiated yeast cells, trehalose is revealed to be primary substrate for endogeneous carbohydrate metabolism, so it is proved that the enzymic patterns are not changed but the activities of enzymes relating endogeneous respiration and autofermentation is activated. It is to be considerable to distiguish endogeneous respiration and autofermentation from exogeneous respiration and fermentation on irradiation, for membrane permeability changes and loses out carbohydrate by ionizing radiation.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.5
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• pp.351-358
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• 2013

A suitable supply of mineral elements into shoot via a root system from growth media makes plants favorable growth and yield. The shortage or surplus of minerals directly affects overall physiological reactions to plants and, especially, strongly influences carbohydrate metabolism as a primary response. We have studied mineral uptake and synthesis and translocation of soluble carbohydrates in N, P or K-deficient tomato plants, and examined the interaction between soluble carbohydrates and mineral elements. Four-weeks-old tomato plants were grown in a hydroponic growth container adjusted with suboptimal N ($0.5mmol\;L^{-1}\;Ca(NO_3)2{\cdot}4H_2O$ and $0.5mmol\;L^{-1}\;KNO_3$), P ($0.05mmol\;L^{-1}\;KH_2PO_4$), and K ($0.5mmol\;L^{-1}\;KNO_3$) for 30 days. The deficiency of specific mineral element led to a significant decrease in its concentration and affected the concentration of other elements with increasing treatment period. The appearance of the reduction, however, differed slightly between elements. The ratios of N uptake of each treatment to that in NPK sufficient tomato shoots were 4 (N deficient), 50 (P deficient), and 50% (K deficient). The P uptake ratios were 21 (N deficient), 19 (P deficient), and 28% (K deficient) and K uptake ratios were 11 (N deficient), 46 (P deficient), and 7% (K deficient). The deficiency of mineral elements also influenced on carbohydrate metabolism; soluble sugar and starch was substantially enhanced, especially in N or K deficiency. In conclusion, mineral deficiency leads to an adverse carbohydrate metabolism such as immoderate accumulation and restricted translocation as well as reduced mineral uptake and thus results in the reduced plant growth.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.9-21
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• 2005

To study the biochemical and physiological role of the plastidic glucose transporter (pGlcT) in carbohydrate metabolism, we characterized transgenic plants with mutations in the pGlcT gene (GT), gt-1 and gt-2, as well double mutants of GT and the maltose transporter (MEX1) and GT and the triose phosphate/phosphate translocator (TPT), GT and the cytosolic fructose-1,6-bisphosphatase gene (cFBP), and MEX1 and TPT, gt-1/mex2, gt-1/tpt-2, gt-1/cfbp-1, mex1-1/tpt-2, respectively. Compared to the wild type, all mutants except the gt-1/cfbp-1 mutant lines displayed higher starch accumulation and higher levels of maltose. Starch accumulation is due to a decrease in starch turnover, leading to an imbalance between the rates of synthesis and degradation. Sucrose levels of gt alleles were higher than those in wild-type plants during the light period, suggesting possible nightly supplementation via the maltose transport pathway to maintain proper carbohydrate partitioning in the plant leaves. The gt plants displayed less growth retardation than mex1-1 mutant and gt-1/mex2 double mutant displayed accumulativesevere growth retardation as compared to individual gt-1 and mex1-1 mutants, implying that the maltose transporter-mediated pathway is a major route for carbohydrate partitioning at night. The gt-1/tpt-2, mex1-1/tpt-2 and gt-1/cfbp-1 double mutants had retarded growth and low chlorophyll content to differing degrees, indicating that photosynthetic capacity had diminished. Interestingly, the gt-1/tpt-2 line displayed a glucose-insensitive phenotype and higher germination rates than wild type, suggesting its involvement not only in carbon partitioning, but also in the sugar signaling network of the pGlcT and TPT.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.509-516
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• 2014

This study was done to investigate the carbohydrate metabolism related enzyme activities and antioxidative effects of Nelumbo nucifera(N.N) Root in streptozotocin (STZ)-induced diabetic rats. The contents of serum glucose, triglyceride (TG) and Total cholesterol were significantly decreaed in N.n treated group compared to the those of STZ-control group. The activity of glucose-6-pase(G-6-Pase) was significantly decreased in N.N treated group. Also the activity of glucokinase(Gk) was significantly increaed in N.N treated group. The content of hepatic glycogen was significantly increaed in N.N treated group, in addition, content of malondialdehyde(MDA) was significanly decreased in N.N treated group. Also, content of glutathione(GSH) was significanly increased in N.N treated froup. whereas, activity of catalase(CAT) was significantly decreaed in N.N treated group compared to the those of STZ-control group. activity of glutathione peroxidase(GSH-Px) was inecreaed. In conclusion, these results indicated that ethanol extract of N.N would have carbohydrate metabolism antioxidative effects in STZ-induced diabetic rats.

• Applied Biological Chemistry
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• v.41 no.4
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• pp.222-227
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• 1998

The activities of enzymes of carbohydrate metabolism have been determinated in the host cytosolic and bacteroid fractions of cowpea (Vigna unguiculata) nodules formed with B. japonicum I 16 and in roots of nodulated cowpeas. The host cytosolic fraction of the nodules contained the enzymes of glycolytic pathway and the pentose phosphate pathway, whereas the bacteroids had only limited capacity for carbohydrate metabolism and appeared to be insufficient for the complete glycolytic pathway as well as starch synthesis and degradation. In a time-course study, using plants grown in a glasshouse, the acetylene-reducing activity (ARA) of the nodules increased in parallel with the total N content of plants and protein of the nodules until approximately 8 weeks after planting. Subsequently, the weight and size of the nodules and the weight of the plants continued to increase, but there was a sharp decrease in the ARA and the total N content of the plants.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.277-284
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• 2014

The ethanol extraction yield of Meliae toosendan fructus(MT) was about 24.5% by extract apparatus. This study was done to investigate the carbohydrate metabolism related enzyme activities and antioxidative effects of MT in streptozotocin (STZ)-induced diabetic rats. The contents of serum glucose, triglyceride (TG) were significantly decreaed in MT treated group compared to the those of STZ-control group, also content of Total cholesterol was decreased. High density lipoprotein (HDL)-cholesterol was increased in MT treated group. The activity of glucose-6-pase(G-6-Pase) was significantly decreased in MT treated group. Also the activities of glucose-6-phosphate dehydrogenase(G-6-PDH) and glucokinase(Gk) were increaed in MT treated group. The content of hepatic glycogen was significantly increaed in MT treated group, in addition, content of malondialdehyde(MDA) was significanly decreased in MT treated group. Also, content of glutathione(GSH)was dereased in MT treated froup. whereas, activity of catalase(CAT) was significantly increaed in MT treated group compared to the those of STZ-control group. activity of glutathione peroxidase(GSH-Px) was inecreaed. In conclusion, these results indicated that ethanol extract of MT would have carbohydrate metabolism antioxidative effects in STZ-induced diabetic rats.

• Journal of Life Science
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• v.11 no.1
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• pp.14-21
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• 2001

To investigate the changes of carbohydrate metabolism in the senescing leaves of Zea mays during dark-induced senescence, the changes in the contents of reducing sugar, sucrose and starch as well as the activities of sucrose synthase, three isozymes of invertase, and ${\alpha}$-amylase were measured. In the senescing leaves, the content of reducing sugars temporarily increased at 4 d and rapidly decreased thereafter, whereas sucrose contents gradually decreased thereafter, whereas sucrose contents gradually decreased until 3 d of senscence and significantly decreased thereafter. The activities of intracellular invertases such as soluble acid and alkaline formed gradually enhanced until 4 d of leaf senescence and significantly declined thereafter. The extracellular invertase activity showed no significant changes during leaf senescence. The deactivation of sucrose synthase was observed within 3 d of leaf senscence. On the other hand, the starch contents gradually declined during 2 d of leaf senescence, and showed a temporary increase at 3 d, which is similar to the pattern of sucrose synthase activity., These results imply that sucrose in the senescing leaves. The major enzymes which correlated to the breakdown of sucrose during dark-induced senescence were soluble acid and alkaline invertases, not sucrose and ABA accelerated leaf senescence by inducing the accumulation of reducing sugar. These result, therefore, that leaf senescence may be mediated by the temporary quantitative changes of reducing sugar induced by the activation of intracellualr inveertases.