Sugar Levels Modulate Differential Expression of Maize Sucrose Synthase Genes

1992 ◽  
Vol 4 (1) ◽  
pp. 59 ◽  
Author(s):  
Karen E. Koch ◽  
Kurt D. Nolte ◽  
Edwin R. Duke ◽  
Donald R. McCarty ◽  
Wayne T. Avigne
1992 ◽  
pp. 59-69 ◽  
Author(s):  
K. E. Koch ◽  
K. D. Nolte ◽  
E. R. Duke ◽  
D. R. McCarty ◽  
W. T. Avigne

2003 ◽  
Vol 60 (2) ◽  
pp. 239-244 ◽  
Author(s):  
José Carlos da Silva ◽  
José Donizeti Alves ◽  
Amauri Alves de Alvarenga ◽  
Marcelo Murad Magalhães ◽  
Dárlan Einstein do Livramento ◽  
...  

One management practice of which the efficiency has not yet been scientifically tested is spraying coffee plants with diluted sucrose solutions as a source of carbon for the plant. This paper evaluates the effect of foliar spraying with sugar on the endogenous level of carbohydrates and on the activities of invertase and sucrose synthase in coffee (Coffea arabica L.) seedlings with reduced (low) and high (normal) levels of carbon reserve. The concentrations used were 0.5 and 1.0% sucrose, and water as a control. The use of sucrose at 1.0% caused an increase in the concentration of total soluble sugars in depauperate plants, as well as increased the activity of the following enzymes: cell wall and vacuole acid invertase, neutral cytosol invertase and sucrose synthase. In plants with high level of carbon reserve, no increments in total soluble sugar levels or in enzymatic activity were observed. Regardless of treatments or plants physiological state, no differences in transpiration or stomatal conductance were observed, demonstrating the stomatal control of transpiration. Photosynthesis was stimulated with the use of 0.5 and 1.0 % sucrose only in depauperate plants. Coffee seedling spraying with sucrose is only efficient for depauperate plants, at the concentration of 1.0%.


1990 ◽  
Vol 115 (2) ◽  
pp. 278-281 ◽  
Author(s):  
Takaya Moriguchi ◽  
Tetsuro Sanada ◽  
Shohei Yamaki

Sugar levels and composition were determined in developing `Hakuto' peach (Prunus persica Batsch var. vulgaris Maxim.) fruit. Glucose and fructose in nearly equal amounts were the predominant sugars detected during the early stage of development. Sucrose subsequently began to accumulate and was the predominant sugar in mature fruit. Sorbitol remained at a low level throughout development. The large increase in the amount of sucrose was accompanied by a rapid increase in sucrose synthase (EC 2.4.1.13) activity. Sucrose phosphate synthase (EC 2.4.1.14) was also detected in flesh extracts, but the activities were low throughout development. Acid invertase (EC 3.2.1.26) activity was highest in young fruit and declined with development. Activity, however, increased again at a later stage of development. Peach fruit contained appreciable sorbitol oxidase activity, while other sorbitol-related enzymes were barely detectable, suggesting that transported sorbitol was predominantly converted to glucose. These results suggest that the supply of glucose and fructose depends on acid invertase and sorbitol oxidase, and that accumulation of sucrose depends on-sucrose synthase.


2014 ◽  
Vol 23 (1) ◽  
pp. 48-59 ◽  
Author(s):  
Joaquin Hasperue ◽  
María Lemoine ◽  
Alicia Chaves ◽  
Gustavo Adolfo Martínez

  Loss of sugars contributes to accelerate postharvest senescence of broccoli. Several treatments have been developed to delay senescence, but in many cases their effects on sugar metabolism were not analyzed. We studied the effect of harvest at different times of day (08:00, 13:00 and 18:00 h) and of several postharvest treatments as heat treatment (HT), modified atmosphere (MA) and 1-methylcylcopropene (1-MCP) on sugar levels and activities of enzymes related to sucrose and starch degradation. Harvesting at the end of day delayed the loss of chlorophylls and caused the lowest decrement in sugars, although no differences in invertase, sucrose synthase and β-amylase activities were detected among samples. Treatments of MA and 1-MCP caused a lower loss of glucose and fructose, while HT caused a lower decrement of sucrose. Treated samples maintained higher levels of chlorophylls. The treatments reduced the activity of invertase and sucrose synthase and induced higher levels of β-amylase activity. Harvesting at the end of day and performing simultaneously a MA treatment could be a good combination to maintain the green color of the inflorescence and sugar levels during postharvest of broccoli.


2014 ◽  
pp. n/a-n/a ◽  
Author(s):  
Dong-Joo Cheon ◽  
Ann E. Walts ◽  
Jessica A. Beach ◽  
Jenny Lester ◽  
John S. Bomalaski ◽  
...  

Author(s):  
Burton B. Silver ◽  
Ronald S. Nelson

Some investigators feel that insulin does not enter cells but exerts its influence in some manner on the cell surface. Ferritin labeling of insulin and insulin antibody was used to determine if binding sites of insulin to specific target organs could be seen with electron microscopy.Alloxanized rats were considered diabetic if blood sugar levels were in excess of 300 mg %. Test reagents included ferritin, ferritin labeled insulin, and ferritin labeled insulin antibody. Target organs examined were were diaphragm, kidney, gastrocnemius, fat pad, liver and anterior pituitary. Reagents were administered through the left common carotid. Survival time was at least one hour in test animals. Tissue incubation studies were also done in normal as well as diabetic rats. Specimens were fixed in gluteraldehyde and osmium followed by staining with lead and uranium salts. Some tissues were not stained.


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