scholarly journals Physiology of Pea Fruits

1969 ◽  
Vol 22 (5) ◽  
pp. 1145 ◽  
Author(s):  
JF Turner
Keyword(s):  
Maximum Rate ◽  
Starch Synthesis ◽  
Maximum Activity ◽  
Stages Of Development ◽  
Starch Formation ◽  
Pea Seed

Changes in UDPG pyrophosphorylase and ADPG pyrophosphorylase and a number of other constituents were followed during the growth of the pea seed. At all stages of development of the seed UDPG pyrophosphorylase activity was much higher than ADPG pyrophosphorylase activity. During the period of starch formation there was a similarity in the changes in starch and UDPG pyrophosphory-lase and ADPG pyrophosphorylase. The maximum rate of starch synthesis coincided with the maximum activity of ADPG pyrophosphorylase. The results are consistent with the biosynthesis of starch from ADPG but do not preclude the participation of UDPG as substrate in this process. It is suggested that UDPG pyrophosphorylase may provide a source of glucose I-phosphate from sucrose for ADPG formation.

scholarly journals Physiology of Pea Fruits III. Changes in Starch and-Starch Phosphorylase in the Developing Seed

1957 ◽  
Vol 10 (3) ◽  
pp. 302 ◽  
Author(s):  
Donflla H Turner ◽  
JF Turner
Keyword(s):  
Linear Relationship ◽  
Starch Content ◽  
Starch Synthesis ◽  
Sucrose Content ◽  
Starch Phosphorylase ◽  
Phosphorylase Activity ◽  
Developing Seed ◽  
Pea Seeds ◽  
Starch Formation ◽  
Pea Seed

During the growth of pea seeds there is a period in which the starch content rises rapidly and the sucrose content falls. This paper describes a study of the control of this starch synthesis. A method was developed for the assay of starch phosphorylase in peas and the changes in enzyme activity during development of the pea seed were followed. Over most of the period of development a linear relationship existed between the rate of starch synthesis and starch phosphorylase activity. It is suggested that the activity of starch phosphorylase may be a major factor in controlling the rate of starch formation in the pea. The rate of starch synthesis began to decrease when the pea ceased to gain water and the linear relationship then no longer held. The bearing of these observations on sugar--starch relationships and on the general problems of growth is discussed.

scholarly journals Physiology of Pea Fruits IV. Changes in Sugars in the Developing Seed

1957 ◽  
Vol 10 (4) ◽  
pp. 407 ◽  
Author(s):  
JF Turner ◽  
Donella H Turner ◽  
JB Lee
Keyword(s):  
Starch Synthesis ◽  
The Other ◽  
Plant Tissues ◽  
Stages Of Development ◽  
Early Stages ◽  
Chromatographic Methods ◽  
Developing Seed ◽  
Pea Seed ◽  
Galactose Content

Paper chromatographic methods were developed for the estimation of sugars in plant tissues and were used to follow changes in some individual sugars during the development of the pea seed. Sucrose was the predominant sugar present in the seeds and there were smaller quantities of fructose, glucose, and galactose. The amounts of fructose and glucose were approximately equal at all stages of develop. ment. The sucrose, fructose, and glucose contents of the seed increased in the early stages of development but decreased during the phase of rapid starch synthesis. The galactose content increased to a maximum at a later state than the other sugars estimated. The concentrations of sucrose, fructose, and glucose in the seeds were compared with the concentrations in the leaves, stems, and hulls. The possible significance of the changes in sugars in relation to the metabolism of the pea seed is discussed.

scholarly journals The role of creatine kinase and arginine kinase in muscle

1978 ◽  
Vol 172 (3) ◽  
pp. 533-537 ◽  
Author(s):  
E A Newsholme ◽  
I Beis ◽  
A R Leech ◽  
V A Zammit
Keyword(s):  
Creatine Kinase ◽  
Maximum Rate ◽  
Skeletal Muscles ◽  
Flight Muscle ◽  
Insect Flight ◽  
Arginine Kinase ◽  
Maximum Activity ◽  
Insect Flight Muscle ◽  
Atp Turnover

Arginine and creatine kinase activities in different muscles are compared with calculated maximum rates of ATP turnover. The magnitude of the kinase activities decreases in the following order: anaerobic muscles and vertebrate skeletal muscles greater than heart muscle greater than insect flight muscle. The maximum activity of phosphagen kinases (i.e. creatine kinase and arginine kinase), in the direction of phosphagen formation, is lower than the calculated maximum rate of ATP turnover in insect flight muscle or rat heart.

scholarly journals Proteomics reveals the effects of drought stress on the kernel development and starch formation of waxy maize

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jian Guo ◽  
Lingling Qu ◽  
Yifan Hu ◽  
Weiping Lu ◽  
Dalei Lu
Keyword(s):  
Drought Stress ◽  
Rice Genome ◽  
Starch Synthesis ◽  
Reduction Process ◽  
Endosperm Development ◽  
Starch Accumulation ◽  
Kernel Development ◽  
Waxy Maize ◽  
Yield And Quality ◽  
Starch Formation

Abstract Background Kernel development and starch formation are the primary determinants of maize yield and quality, which are considerably influenced by drought stress. To clarify the response of maize kernel to drought stress, we established well-watered (WW) and water-stressed (WS) conditions at 1–30 days after pollination (dap) on waxy maize (Zea mays L. sinensis Kulesh). Results Kernel development, starch accumulation, and activities of starch biosynthetic enzymes were significantly reduced by drought stress. The morphology of starch granules changed, whereas the grain filling rate was accelerated. A comparative proteomics approach was applied to analyze the proteome change in kernels under two treatments at 10 dap and 25 dap. Under the WS conditions, 487 and 465 differentially accumulated proteins (DAPs) were identified at 10 dap and 25 dap, respectively. Drought induced the downregulation of proteins involved in the oxidation–reduction process and oxidoreductase, peroxidase, catalase, glutamine synthetase, abscisic acid stress ripening 1, and lipoxygenase, which might be an important reason for the effect of drought stress on kernel development. Notably, several proteins involved in waxy maize endosperm and starch biosynthesis were upregulated at early-kernel stage under WS conditions, which might have accelerated endosperm development and starch synthesis. Additionally, 17 and 11 common DAPs were sustained in the upregulated and downregulated DAP groups, respectively, at 10 dap and 25 dap. Among these 28 proteins, four maize homologs (i.e., A0A1D6H543, B4FTP0, B6SLJ0, and A0A1D6H5J5) were considered as candidate proteins that affected kernel development and drought stress response by comparing with the rice genome. Conclusions The proteomic changes caused by drought were highly correlated with kernel development and starch accumulation, which were closely related to the final yield and quality of waxy maize. Our results provided a foundation for the enhanced understanding of kernel development and starch formation in response to drought stress in waxy maize.

The Effect of High Temperature on Starch Synthesis and the Activity of Starch Synthase

1994 ◽  
Vol 21 (6) ◽  
pp. 783 ◽  
Author(s):  
K Denyer ◽  
CM Hylton ◽  
AM Smith
Keyword(s):  
High Temperature ◽  
Starch Content ◽  
Starch Synthesis ◽  
Soluble Starch ◽  
Maximum Activity ◽  
Starch Synthase ◽  
Heat Inactivation ◽  
Heat Sensitivity ◽  
Potato Tubers ◽  
Storage Organs

The decrease in yield which is observed when developing storage organs such as cereal grains or potato tubers are exposed to high temperatures is due to a lower final starch content. The rate of starch synthesis during the development of these storage organs at high temperature, is either reduced or fails to increase sufficiently to compensate for the shorter developmental period. This effect on the rate of starch synthesis does not seem to be due to a reduction in the supply of photosynthate. One of the enzymes in the pathway of starch synthesis, soluble starch synthase, is susceptible to heat inactivation at unusually low temperatures and may also have a low optimum temperature for maximum activity. In some storage organs, the maximum catalytic activity of soluble starch synthase is not very much greater than the rate of starch synthesis. A decrease in the activity of this enzyme is therefore, likely to affect the rate of starch synthesis. Thus, the effect of high temperature on the rate of starch synthesis may be due, at least in part, to the properties of this enzyme. This review discusses the unusual heat-sensitivity of starch synthase in the context ofthe effects of high temperature on starch synthesis in storage organs.

scholarly journals Starch Synthesis and Changes in Uridine Diphosphorlase in the Developing Wheat Grain

1969 ◽  
Vol 22 (6) ◽  
pp. 1321 ◽  
Author(s):  
JF Turner
Keyword(s):  
Reducing Sugars ◽  
Starch Synthesis ◽  
Dry Weight ◽  
Soluble Nitrogen ◽  
Wheat Grain ◽  
Fresh Weight ◽  
Sharp Rise ◽  
Protein Nitrogen ◽  
Starch Formation ◽  
Main Substrate

The enzymes UDPG pyrophosphorylase and ADPG pyrophosphorylase were assayed during the growth of wheat grains. Changes in fresh weight, dry weight, water, sucrose, reducing sugars, starch, total nitrogen, protein nitrogen, and soluble nitrogen were followed simultaneously. Throughout development the activity of UDPG pyrophosphorylase per grain was much greater than the activity of ADPG pyrophosphorylase. Both enzymes increased in activity during the phase of starch synthesis and a sharp rise in ADPG pyrophosphorylase was associated with the onset of rapid starch formation. ADPG pyrophosphorylase activity decreased to a very low level when starch formation in the grain ceased. UDPG pyrophosphorylase activity also decreased at this time. Although the participation of UDPG is not excluded, it is suggested that the main substrate for starch synthesis in the wheat grain is ADPG. A mechanism for the synthesis of starch from sucrose is proposed.

BIOCHEMICAL CHANGES IN DEVELOPING WHEAT GRAINS. I. CHANGES IN PROTEINS, CARBOHYDRATES, AND NUCLEIC ACIDS

1976 ◽  
Vol 56 (2) ◽  
pp. 385-391 ◽  
Author(s):  
AMIN C. KAPOOR ◽  
ROBERT E. HEINER
Keyword(s):  
Nucleic Acid ◽  
Starch Content ◽  
Starch Synthesis ◽  
Triticum Aestivum L ◽  
Grain Protein ◽  
Stages Of Development ◽  
Nonprotein Nitrogen ◽  
Environment Chamber ◽  
True Protein ◽  
Rna And Dna

Two spring wheat cultivars, (Triticum aestivum L.) one tall, Chris, and another semidwarf, Era, with different yield and grain protein potentials, were grown in a controlled environment chamber to compare protein, carbohydrate, and nucleic acid contents in developing grain at 12, 22, 29, and 36 days after heading. Crude protein and true protein of both cultivars increased and the nonprotein nitrogen decreased as the grain matured. Starch content was initially low but increased rapidly during maturation while reducing sugars, sucrose, and fructosans decreased. Starch synthesis started earlier in Chris but was more rapid in Era at later stages of development. Era contained more starch than Chris at maturity. Nucleic acid contents were also affected during grain maturation. Chris, which produced higher amounts of grain protein throughout grain development, also contained higher amounts of RNA and DNA at all stages of development.

Neuronal and Extraneuronal Uptake of 3H-Norepinephrine in the Heart of the Active Bat: An Electron Microscopic Radioautographic Study

1973 ◽  
Vol 31 ◽  
pp. 522-523
Author(s):  
Martin Hagopian ◽  
Michael D. Gershon ◽  
Eladio A. Nunez
Keyword(s):  
Smooth Muscle ◽  
Monoamine Oxidase ◽  
Vascular Smooth Muscle ◽  
Cardiac Muscle ◽  
Maximum Rate ◽  
External Medium ◽  
Extraneuronal Uptake ◽  
Electron Microscopic ◽  
Cardiac Tissues ◽  
High Affinity

The ability of cardiac tissues to take up norepinephrine from an external medium is well known. Two mechanisms, called Uptake and Uptake respectively by Iversen have been differentiated. Uptake is a high affinity system associated with adrenergic neuronal elements. Uptake is a low affinity system, with a higher maximum rate than that of Uptake. Uptake has been associated with extraneuronal tissues such as cardiac muscle, fibroblasts or vascular smooth muscle. At low perfusion concentrations of norepinephrine most of the amine taken up by Uptake is metabolized. In order to study the localization of sites of norepinephrine storage following its uptake in the active bat heart, tritiated norepinephrine (2.5 mCi; 0.064 mg) was given intravenously to 2 bats. Monoamine oxidase had been inhibited with pheniprazine (10 mg/kg) one hour previously to decrease metabolism of norepinephrine.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

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