scholarly journals Studies of the Fixation of Carbon Dioxide by Washed Ram Spermatozoa

1970 ◽  
Vol 23 (4) ◽  
pp. 889 ◽  
Author(s):  
T O'shea ◽  
RG Wales
Keyword(s):  
Carbon Dioxide ◽  
Substrate Concentration ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Fixation Of Carbon Dioxide

Fixation of carbon dioxide by ram spermatozoa was studied by incubating washed cells with NaH14C03? More fixation of carbon dioxide occurred as the substrate concentration was increased, and was very low in the absence of added substrate. Less incorporation occurred with acetate than with pyruvate or lactate. A marked increase in fixation was seen when ketoglutarate or malate replaced portion of the lactate in the medium, but not when other tricarboxylic acid cycle intermediates were substituted. Fixation of carbon dioxide was higher when ketoglutarate plus malate rather than when either substrate alone partially replaced lactate.

scholarly journals Studies of intermediary metabolism in germinating pea cotyledons. The pathway of ethanol metabolism and the role of the tricarboxylic acid cycle

1967 ◽  
Vol 105 (1) ◽  
pp. 323-331 ◽  
Author(s):  
D. S. Cameron ◽  
E. A. Cossins
Keyword(s):  
Carbon Dioxide ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Ethanol Metabolism ◽  
Similar Data ◽  
Tissue Slices ◽  
Acid Cycle ◽  
Pea Seedlings ◽  
Fixation Of Carbon Dioxide

1. The pathway of ethanol metabolism in cotyledons of 3-day-old pea seedlings has been examined by incubating tissue slices with [1−14C]ethanol and [2−14C]ethanol for periods up to 1hr. 2. Ethanol was rapidly incorporated into citrate and glutamate but relatively small amounts of 14C were present in the evolved carbon dioxide even after 1hr. of ethanol metabolism. 3. Similar data were obtained from experiments in which [1,2−14C2]acetaldehyde and [14C]acetate were supplied. 4. The results are interpreted as indicating that ethanol is metabolized essentially via the reactions of the tricarboxylic acid cycle with a substantial drain of α-oxoglutarate to support the biosynthesis of glutamate. 5. It is concluded that oxaloacetate, required for the incorporation of ethanol into citrate, arises mainly from the transamination of aspartate and the fixation of carbon dioxide.

The anaplerotic fixation of carbon dioxide by Escherichia coli

1966 ◽  
Vol 165 (999) ◽  
pp. 179-188 ◽  
Keyword(s):  
Escherichia Coli ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Growth Media ◽  
Wild Type ◽  
Carboxylase Activity ◽  
Acid Cycle ◽  
K 12 ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Fixation Of Carbon Dioxide

The isolation of a mutant (AB 1622) of Escherichia coli K 12 is described, which differs from its parent organism (AB 1621) in lacking the ability to grow upon glucose, glycerol or pyruvate unless utilizable intermediates of the tricarboxylic acid cycle are also supplied in the growth media; both the mutant and its parent grow readily on acetate as sole carbon source. Washed suspensions of AB 1622 oxidized pyruvate only to the level of acetate, which accumulated; when catalytic quantities of L-malate were also supplied, pyruvate was oxidized further and the extent to which it was oxidized approached that observed with suspensions of the wild-type organisms. These observations suggest that the mutant is unable to effect the net formation of tricarboxylic acid cycle intermediates from pyruvate or phosphopyruvate. Analysis of extracts of the mutant, and of its parent organism, showed that the former lacked phosphopyruvate carboxylase activity (EC 4.1.1.31), although other enzymes capable in theory of catalysing the carboxylation of C 3 -acids were abundant in both extracts. It is thus concluded that the net formation of C 4 -acids through carboxylation of C 3 -precursors is necessarily achieved through the agency of phosphopyruvate carboxylase.

scholarly journals Triheptanoin partially restores levels of tricarboxylic acid cycle intermediates in the mouse pilocarpine model of epilepsy

2013 ◽  
Vol 129 (1) ◽  
pp. 107-119 ◽  
Author(s):  
Mussie G. Hadera ◽  
Olav B. Smeland ◽  
Tanya S. McDonald ◽  
Kah Ni Tan ◽  
Ursula Sonnewald ◽  
...  
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Pilocarpine Model ◽  
Tricarboxylic Acid Cycle Intermediates

scholarly journals Metabolic phases during the development of granulation tissue

1967 ◽  
Vol 105 (1) ◽  
pp. 333-341 ◽  
Author(s):  
Kirsti Lampiaho ◽  
E. Kulonen
Keyword(s):  
Granulation Tissue ◽  
Collagen Synthesis ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Pentose Phosphate ◽  
Acid Cycle ◽  
Short Period ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Observation Period

1. The metabolism of incubated slices of sponge-induced granulation tissue, harvested 4–90 days after the implantation, was studied with special reference to the capacity of collagen synthesis and to the energy metabolism. Data are also given on the nucleic acid contents during the observation period. Three metabolic phases were evident. 2. The viability of the slices for the synthesis of collagen was studied in various conditions. Freezing and homogenization destroyed the capacity of the tissue to incorporate proline into collagen. 3. Consumption of oxygen reached the maximum at 30–40 days. There was evidence that the pentose phosphate cycle was important, especially during the phases of the proliferation and the involution. The formation of lactic acid was maximal at about 20 days. 4. The capacity to incorporate proline into collagen hydroxyproline in vitro was limited to a relatively short period at 10–30 days. 5. The synthesis of collagen was dependent on the supply of oxygen and glucose, which latter could be replaced in the incubation medium by other monosaccharides but not by the metabolites of glucose or tricarboxylic acid-cycle intermediates.

The Ethylmalonyl-CoA Pathway for Methane-based Biorefineries: A Case Study of Using Methylosinus trichosporium OB3b, an Alpha-proteobacterial Methanotroph, for Producing 2-Hydroxyisobutyric Acid and 1,3-Butanediol from Methane

2021 ◽  
Author(s):  
Dung Hoang Anh Mai ◽  
Thu Thi Nguyen ◽  
Eun Yeol Lee
Keyword(s):  
Carbon Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Methylosinus Trichosporium Ob3b ◽  
Methylosinus Trichosporium ◽  
Acid Cycle ◽  
Hydroxyisobutyric Acid ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Alpha Proteobacteria

The ethylmalonyl-CoA pathway is one of three known anaplerotic pathways that replenish tricarboxylic acid cycle intermediates and plays a major role in the carbon metabolism of many alpha-proteobacteria including Methylosinus...

13C isotopomer model for estimation of anaplerotic substrate oxidation via acetyl-CoA

1996 ◽  
Vol 271 (4) ◽  
pp. E788-E799 ◽  
Author(s):  
F. M. Jeffrey ◽  
C. J. Storey ◽  
A. D. Sherry ◽  
C. R. Malloy
Keyword(s):  
Biochemical Analysis ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acetyl Coa ◽  
Acid Cycle ◽  
Propionate Metabolism ◽  
13C Nuclear Magnetic Resonance ◽  
Isotopomer Analysis ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Anaplerotic Pathway

A previous model using 13C nuclear magnetic resonance isotopomer analysis provided for direct measurement of the oxidation of 13C-enriched substrates in the tricarboxylic acid cycle and/or their entry via anaplerotic pathways. This model did not allow for recycling of labeled metabolites from tricarboxylic acid cycle intermediates into the acetyl-CoA pool. An extension of this model is now presented that incorporates carbon flow from oxaloacetate or malate to acetyl-CoA. This model was examined using propionate metabolism in the heart, in which previous observations indicated that all of the propionate consumed was oxidized to CO2 and water. Application of the new isotopomer model shows that 2 mM [3-13C]propionate entered the tricarboxylic acid cycle as succinyl-CoA (an anaplerotic pathway) at a rate equal to 52% of tricarboxylic acid cycle turnover and that all of this carbon entered the acetyl-CoA pool and was oxidized. This was verified using standard biochemical analysis; from the rate (mumol.min-1.g dry wt-1) of propionate uptake (4.0 +/- 0.7), the estimated oxygen consumption (24.8 +/- 5) matched that experimentally determined (24.4 +/- 3).

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