Stomatal Metabolism: Carbon Dioxide Fixation in Attached and Detached Epidermis of Commelina

1978 ◽  
Vol 5 (6) ◽  
pp. 767
Author(s):  
C.M Wilmer ◽  
N Thorpe ◽  
J.C Rutter ◽  
F.L Milthorpe
Keyword(s):  
Carbon Dioxide ◽  
Tca Cycle ◽  
Carbon Dioxide Fixation ◽  
Reverse Direction ◽  
Gaseous Exchange ◽  
14Co2 Fixation ◽  
Fixation Pattern ◽  
The Difference ◽  
Sugar Phosphates ◽  
Tca Cycle Intermediates

Rates of accumulation of radioactivity and the nature of 14CO2 fixation products were measured in mesophyll, attached epidermis and detached epidermis of Commelina cyanea and C. communis. In the illuminated detached epidermis of C. cyanea, most of the fixation products were malate and aspartate (in almost equal proportions), with small amounts of sugars, sugar phosphates, serine, glycine, alanine and TCA cycle intermediates. In that of C. communis there was a smaller proportion of aspartate and a higher proportion of sugars, glutamate and tricarboxylic acids. The much higher rates of accumulation of labelled fixation products in attached epidermis of C. cyanea can in part be attributed to glycine, serine and alanine, which appear to be imported from the mesophyll very shortly after the leaf is first exposed to 14CO2. Over longer periods of time, labelled sugars contributed an appreciable and increasing proportion. In C. communis, after 15-30 min, most of the difference between attached and detached epidermis was attributable to the presence of labelled sugars. The fixation pattern in the mesophyll of these species was typical of C*3-type photosynthesis. Autoradiographs of detached epidermis showed that the label was predominantly in stomata while those of attached epidermis showed more label in stomata than elsewhere after 1 min and they were uniformly labelled after 30 min. These findings suggest that metabolites are translocated from the mesophyll to the epidermis fairly readily. There is probably flow in the reverse direction as well as gaseous exchange of 14C between these tissues.

Warm- and Cool-Night Temperatures Alter Carbon Dioxide Fixation Pattern and Biochemical Metabolism in Phalaenopsis aphrodite

2011 ◽  
pp. 181-194
Author(s):  
Ya-Chen Tseng ◽  
Yo-Ching Liu ◽  
Kai-Meng Tseng ◽  
Wen-Huei Chen ◽  
Heng-Long Wang
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Fixation ◽  
Fixation Pattern ◽  
Phalaenopsis Aphrodite ◽  
Cool Night

Incorporation of Inorganic Phosphate into Sugar Phosphates during Carbon Dioxide Fixation by Illuminated Chloroplasts

Nature ◽  
1966 ◽  
Vol 210 (5038) ◽  
pp. 793-796 ◽  
Author(s):  
C. W. BALDRY ◽  
C. BUCKE ◽  
D. A. WALKER
Keyword(s):  
Carbon Dioxide ◽  
Inorganic Phosphate ◽  
Carbon Dioxide Fixation ◽  
Sugar Phosphates

scholarly journals Some effects of sugars and sugar phosphates on carbon dioxide fixation by isolated chloroplasts

1966 ◽  
Vol 101 (3) ◽  
pp. 636-641 ◽  
Author(s):  
C Bucke ◽  
DA Walker ◽  
CW Baldry
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Fixation ◽  
Free Sugars ◽  
Sugar Phosphates ◽  
Related Compounds ◽  
Isolated Chloroplasts

1. Carbon dioxide fixation by isolated pea chloroplasts was stimulated by the addition of intermediates of the Calvin photosynthesis cycle and by some related compounds. 2. Ribose 5-phosphate and fructose 1,6-diphosphate consistently produced the largest effects; free sugars such as erythrose and sedoheptulose and acids such as glycollate and glyoxylate were largely ineffective or even inhibitory. 3. Small effects were produced by fructose and ribose but not by their isomers, glucose and xylose. 4. Maximal rates in the presence of ribose 5-phosphate varied between 10 and 50mumoles of carbon dioxide fixed/mg. of chlorophyll/hr.

scholarly journals Choice between autotrophy and heterotrophy in Pseudomonas oxalaticus. Utilization of oxalate by cells after adaptation from growth on formate to growth on oxalate

1968 ◽  
Vol 107 (5) ◽  
pp. 699-704 ◽  
Author(s):  
Maureen A. Blackmore ◽  
J. R. Quayle ◽  
I O Walker
Keyword(s):  
Carbon Dioxide ◽  
Energy Source ◽  
Dicarboxylic Acids ◽  
Carbon Dioxide Fixation ◽  
Labelling Pattern ◽  
Carboxyl Group ◽  
Isotopic Data ◽  
14Co2 Fixation ◽  
Stages Of Growth ◽  
Autotrophic Metabolism

1. The labelling patterns of phosphoglycerate obtained from formate-grown or oxalate-grown Pseudomonas oxalaticus after exposure for 15sec. to [14C]formate or [14C]oxalate respectively were determined. 2. The phosphoglycerate obtained from the formate-grown cells contained 78% of the radioactivity in the carboxyl group. This is in accord with that predicted for operation of the ribulose diphosphate cycle of carbon dioxide fixation. 3. The labelling pattern of the phosphoglycerate obtained from the oxalate-grown cells approached uniformity, as predicted for the heterotrophic pathway of oxalate assimilation. The departure from complete uniformity may have been due to concurrent 14CO2 fixation into C4 dicarboxylic acids. 4. The labelling pattern of phosphoglycerate obtained from cells that had just started to grow on oxalate after adaptation from formate was determined after incubation of the cells for 15sec. with [14C]oxalate. This pattern approached uniformity. 5. The pathway of incorporation of 14CO2 into cells that had just started to grow on oxalate after adaptation from formate, in the presence of either formate or oxalate as energy source, was studied by chromatographic and radio-autographic analysis. 6. It is concluded from the isotopic data that a mixed heterotrophic–autotrophic metabolism, with the former mode predominating, operates in the initial stages of growth on oxalate after adaptation from growth on formate.

scholarly journals Calvin-cycle intermediates in relation to induction phenomena in photosynthetic carbon dioxide fixation by isolated chloroplasts

1966 ◽  
Vol 101 (3) ◽  
pp. 642-646 ◽  
Author(s):  
CW Baldry ◽  
DA Walker ◽  
C Bucke
Keyword(s):  
Carbon Dioxide ◽  
Calvin Cycle ◽  
Carbon Dioxide Fixation ◽  
Chloroplast Envelope ◽  
Induction Periods ◽  
New Synthesis ◽  
Photosynthetic Carbon ◽  
Sugar Phosphates ◽  
Isolated Chloroplasts ◽  
Additional Fixation

1. Induction periods in carbon dioxide fixation by isolated pea chloroplasts were shortened by small quantities of Calvin-cycle intermediates. The additional fixation was larger than that which would have followed direct stoicheiometric conversion into ribulose 1,5-diphosphate. 2. When chloroplasts were illuminated in the absence of added substrates (other than carbon dioxide) soluble products were formed in the medium that stimulated fixation by fresh chloroplasts. 3. The induction periods were lengthened by washing the chloroplasts. Addition of catalytic quantities of Calvin-cycle intermediates then decreased the induction periods to their previous values. 4. The induction period was extended by a decrease in temperature but was largely unaffected by a decrease in light-intensity that was sufficient to decrease the maximum rate. 5. It is concluded that the lag periods are a consequence of the loss of Calvin-cycle intermediates, such as sugar phosphates, through the intact chloroplast envelope and that these losses can be made good by new synthesis from carbon dioxide in the reactions of the Calvin cycle.

Control of the Carbon Dioxide Fixation in Escherichia coli by the Compounds Related to TCA Cycle*

1968 ◽  
Vol 63 (4) ◽  
pp. 532-541 ◽  
Author(s):  
TSUKASA NISHIKIDO ◽  
KATSURA IZUI ◽  
AKITOSHI IWATANI ◽  
HIROHIKO KATSUKI ◽  
SHOZO TANAKA
Keyword(s):  
Escherichia Coli ◽  
Carbon Dioxide ◽  
Tca Cycle ◽  
Carbon Dioxide Fixation

Inhibition of the carbon dioxide fixation in E. coli by the compounds related to TCA cycle

1965 ◽  
Vol 21 (2) ◽  
pp. 94-99 ◽  
Author(s):  
T. Nishikido ◽  
K. Izui ◽  
A. Iwatani ◽  
H. Katsuki ◽  
S. Tanaka
Keyword(s):  
Carbon Dioxide ◽  
Tca Cycle ◽  
Carbon Dioxide Fixation ◽  
E Coli

Stomatal Metabolism: Carbon Dioxide Fixation and Labelling Patterns during Stomatal Movement in Commelina cyanea

1979 ◽  
Vol 6 (3) ◽  
pp. 409
Author(s):  
N Thorpe ◽  
C.M Willmer ◽  
F.L Milthorpe
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Fixation ◽  
Stomatal Movement ◽  
Sugar Phosphates

Epidermal strips floated on solutions with NaH14CO3 fixed 14C about three times as quickly when the stomata were opening or closing as they did when either open or closed. The proportions of the major fixation products-malate, aspartate, sugars and sugar phosphates, glycine, serine and alanine-were very similar during the opening, open and closed phases but, when closing, an appreciably higher proportion was diverted to sugars and sugar phosphates. There was a relatively greater leakage into the medium of labelled malate during the open, closed and closing phases than during opening.

scholarly journals NMR Determination of the TCA Cycle Rate and α-Ketoglutarate/Glutamate Exchange Rate in Rat Brain

1992 ◽  
Vol 12 (3) ◽  
pp. 434-447 ◽  
Author(s):  
Graeme F. Mason ◽  
Douglas L. Rothman ◽  
Kevin L. Behar ◽  
Robert G. Shulman
Keyword(s):  
Exchange Rate ◽  
Rat Brain ◽  
Tca Cycle ◽  
Isotopic Labeling ◽  
Cycle Rate ◽  
The Tca Cycle ◽  
The Difference ◽  
Tca Cycle Intermediates

A mathematical model of cerebral glucose metabolism was developed to analyze the isotopic labeling of carbon atoms C4 and C3 of glutamate following an intravenous infusion of [1-13C]glucose. The model consists of a series of coupled metabolic pools representing glucose, glycolytic intermediates, tricarboxylic acid (TCA) cycle intermediates, glutamate, aspartate, and glutamine. Based on the rate of 13C isotopic labeling of glutamate C4 measured in a previous study, the TCA cycle rate in rat brain was determined to be 1.58 ± 0.41 μmol min−1 g−1 (mean ± SD, n = 5). Analysis of the difference between the rates of isotopic enrichment of glutamate C4 and C3 permitted the rate of exchange between α-ketoglutarate (α-KG) and glutamate to be assessed in vivo. In rat brain, the exchange rate between α-KG and glutamate is between 89 ± 35 and 126 ± 22 times faster than the TCA cycle rate (mean ± SD, n = 4). The sensitivity of the calculated value of the TCA cycle rate to other metabolic fluxes and to concentrations of glycolytic and TCA cycle intermediates was tested and found to be small.

scholarly journals What Constitutes a Gluconeogenic Precursor?

2020 ◽  
Vol 150 (9) ◽  
pp. 2239-2241
Author(s):  
Mark A Tetrick ◽  
Jack Odle
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Chain Length ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Tca Cycle ◽  
Acid Oxidation ◽  
The Tca Cycle ◽  
Glucose Synthesis ◽  
Tca Cycle Intermediates

ABSTRACT A gluconeogenic precursor is a biochemical compound acted on by a gluconeogenic pathway enabling the net synthesis of glucose. Recognized gluconeogenic precursors in fasting placental mammals include glycerol, lactate/pyruvate, certain amino acids, and odd-chain length fatty acids. Each of these precursors is capable of contributing net amounts of carbon to glucose synthesis via the tricarboxylic acid cycle (TCA cycle) because they are anaplerotic, that is, they are able to increase the pools of TCA cycle intermediates by the contribution of more carbon than is lost via carbon dioxide. The net synthesis of glucose from even-chain length fatty acids (ECFAs) in fasting placental mammals, via the TCA cycle alone, is not possible because equal amounts of carbon are lost via carbon dioxide as is contributed from fatty acid oxidation via acetyl-CoA. Therefore, ECFAs do not meet the criteria to be recognized as a gluconeogenic precursor via the TCA cycle alone. ECFAs are gluconeogenic precursors in organisms with a functioning glyoxylate cycle, which enables the net contribution of carbon to the intermediates of the TCA cycle from ECFAs and the net synthesis of glucose. The net conversion of ECFAs to glucose in fasting placental mammals via C3 metabolism of acetone may be a competent though inefficient metabolic path by which ECFA could be considered a gluconeogenic precursor. Defining a substrate as a gluconeogenic precursor requires careful articulation of the definition, organism, and physiologic conditions under consideration.

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