Mitochondrial oxidative enzymes and phosphorylations in cold exposure and hibernation

1961 ◽  
Vol 201 (1) ◽  
pp. 29-32 ◽  
Author(s):  
Rowand R. J. Chaffee ◽  
Frederic L. Hoch ◽  
Charles P. Lyman
Keyword(s):  
Cold Exposure ◽  
Golden Hamster ◽  
Reductase Activity ◽  
Wistar Rat ◽  
Oxidative Capacity ◽  
Liver Mitochondria ◽  
Oxidative Enzymes ◽  
Temperature Sensitive ◽  
Oxidase System ◽  
Oxidative Phosphorylations

Oxidative enzyme activities and oxidative phosphorylations of the liver mitochondria of a hibernating species, the golden hamster, and a nonhibernating species, the albino Wistar rat, were examined for changes in response to prolonged cold exposure. Succinic and glutamic oxidase, succinic-triphenyltetrazolium reductase, and cytochrome oxidase activities were measured. The mitochondria from cold-exposed rats showed no major changes (except for a high succinic-triphenyltetrazolium reductase activity), and normal P:O ratios (moles of phosphate esterified per gram atom O2 consumed). In both active and hibernating cold-exposed hamsters, all oxidative enzymes measured at 37 C were increased in activity, and the P:O ratios were normal. The mitochondria of hibernators contain a temperature-sensitive succinic oxidase system; when measured at 7 C, this activity is lower in the hibernators than in active cold-exposed animals or control animals. On the basis of the criteria used here hibernation does not involve a loss of oxidative capacity.

Temperature-sensitive DNA mutant of Chinese hamster ovary cells with a thermolabile ribonucleotide reductase activity

1990 ◽  
Vol 10 (11) ◽  
pp. 5688-5699
Author(s):  
B E Wojcik ◽  
J J Dermody ◽  
H L Ozer ◽  
B Mun ◽  
C K Mathews
Keyword(s):  
Dna Synthesis ◽  
Ribonucleotide Reductase ◽  
Chinese Hamster Ovary ◽  
Reductase Activity ◽  
Chinese Hamster ◽  
Temperature Shift ◽  
Ovary Cell ◽  
Temperature Sensitive ◽  
Dntp Pool ◽  
Ribonucleotide Reductase Activity

JB3-B is a Chinese hamster ovary cell mutant previously shown to be temperature sensitive for DNA replication (J. J. Dermody, B. E. Wojcik, H. Du, and H. L. Ozer, Mol. Cell. Biol. 6:4594-4601, 1986). It was chosen for detailed study because of its novel property of inhibiting both polyomavirus and adenovirus DNA synthesis in a temperature-dependent manner. Pulse-labeling studies demonstrated a defect in the rate of adenovirus DNA synthesis. Measurement of deoxyribonucleoside triphosphate (dNTP) pools as a function of time after shift of uninfected cultures from 33 to 39 degrees C revealed that all four dNTP pools declined at similar rates in extracts prepared either from whole cells or from rapidly isolated nuclei. Ribonucleoside triphosphate pools were unaffected by a temperature shift, ruling out the possibility that the mutation affects nucleoside diphosphokinase. However, ribonucleotide reductase activity, as measured in extracts, declined after cell cultures underwent a temperature shift, in parallel with the decline in dNTP pool sizes. Moreover, the activity of cell extracts was thermolabile in vitro, consistent with the model that the JB3-B mutation affects the structural gene for one of the ribonucleotide reductase subunits. The kinetics of dNTP pool size changes after temperature shift are quite distinct from those reported after inhibition of ribonucleotide reductase with hydroxyurea. An indirect effect on ribonucleotide reductase activity in JB3-B has not been excluded since human sequences other than those encoding the enzyme subunits can correct the temperature-sensitive growth defect in the mutant.

Physiological and biochemical correlates of increased work in trained iron-deficient rats

1988 ◽  
Vol 65 (1) ◽  
pp. 256-263 ◽  
Author(s):  
W. T. Willis ◽  
P. R. Dallman ◽  
G. A. Brooks
Keyword(s):  
Skeletal Muscle ◽  
Nadh Oxidase ◽  
Tca Cycle ◽  
Work Capacity ◽  
Oxidative Capacity ◽  
Oxidative Enzymes ◽  
Tca Cycle Enzymes ◽  
Iron Deficient ◽  
Old Rats ◽  
Physiological And Biochemical

We investigated physiological and biochemical factors associated with the improved work capacity of trained iron-deficient rats. Female 21-day-old rats were assigned to one of four groups, two dietary groups (50 and 6 ppm dietary iron) subdivided into two levels of activity (sedentary and treadmill trained). Iron deficiency decreased hemoglobin (61%), maximal O2 uptake. (VO2max) (40%), skeletal muscle mitochondrial oxidase activities (59-90%), and running endurance (94%). In contrast, activities of tricarboxylic acid (TCA) cycle enzymes in skeletal muscle were largely unaffected. Four weeks of mild training in iron-deficient rats resulted in improved blood lactate homeostasis during exercise and increased VO2max (15%), TCA cycle enzymes of skeletal muscle (27-58%) and heart (29%), and liver NADH oxidase (34%) but did not affect any of these parameters in the iron-sufficient animals. In iron-deficient rats training affected neither the blood hemoglobin level nor any measured iron-dependent enzyme pathway of skeletal muscle but substantially increased endurance (230%). We conclude that the training-induced increase in endurance in iron-deficient rats may be related to cardiovascular improvements, elevations in liver oxidative capacity, and increases in the activities of oxidative enzymes that do not contain iron in skeletal and cardiac muscle.

Nonshivering thermogenesis induced by repetitive hypothalamic cooling in the rat

1976 ◽  
Vol 230 (2) ◽  
pp. 522-526 ◽  
Author(s):  
M Banet ◽  
H Hensel
Keyword(s):  
Oxygen Uptake ◽  
Cold Exposure ◽  
Preoptic Area ◽  
Temperature Sensitive ◽  
Nonshivering Thermogenesis ◽  
Hypothalamic Area ◽  
Hypothalamic Temperature ◽  
Experimental Animals ◽  
Unanesthetized Animals ◽  
Better Than

The effect of prolonged and repetitive cooling of the preoptic/anterior hypothalamic area on the sensitivity to the metabolic effect of noradrenaline and on the resistance to cold exposure was studied in the white rat. The preoptic area of 18 unanesthetized animals was cooled 9 h/day 5 days/wk, for a total of 80-150 h. One hour after a noradrenaline test injection (0.4 mg/kg), the experimental animals in which the preoptic area had been cooled to about 24 degrees C increased oxygen uptake by 81%, whereas those in which the preoptic area had been cooled to about 28 degrees C increased oxygen uptake by 48% (the control animals by only 37%). Despite their increased capacity for nonshivering thermogenesis, the experimental animals did not tolerate cold exposure (-10 degrees C) better than the controls. This development of nonshivering thermogenesis is thought to have been mediated by the hypothalamic temperature-sensitive neurons, and the possibility that it could explain the shift from shivering to nonshivering thermogenesis seen during adaptation to cold is discussed.

RESPIRATORY CARRIERS AND THE NATURE OF THE REDUCED DIPHOSPHOPYRIDINE NUCLEOTIDE OXIDASE SYSTEM IN XANTHOMONAS PHASEOLI

1960 ◽  
Vol 38 (1) ◽  
pp. 79-93 ◽  
Author(s):  
R. M. Hochster ◽  
C. G. Nozzolillo
Keyword(s):  
Cytochrome C ◽  
Reductase Activity ◽  
Inorganic Ions ◽  
Product Formation ◽  
Intact Cells ◽  
Oxidase System ◽  
Clear Cut ◽  
Highly Active ◽  
Inhibitor Study ◽  
Terminal Oxidation

Intact cells and cell-free extracts of the phytopathogenic organism Xanthomonas phaseoli have been shown to contain flavoprotein and the respiratory carriers: cytochrome b1, cytochrome a1, and cytochrome a2. The reduced forms of these respiratory pigments are produced upon addition to a clear extract of substrate amounts of DPNH.The highly active DPNH oxidase system in extracts of this organism has been studied as to requirements for inorganic ions, optimum pH, product formation, distribution, and solubilization. Carbon monoxide inhibits the terminal oxidation system; this effect is reversed by bright light.An inhibitor study has shown members of the phenothiazine family of compounds to be most effective, followed by amytal, cyanide, BAL, atabrine, and pCMB. The most notable of the substances which did not inhibit were antimycin A, one of the quinoline-N-oxides, and azide.The possibility exists that H2O2may also be formed during the oxidation of DPNH although clear-cut evidence for its presence was difficult to obtain. X. phaseoli extracts do not contain a DPNH peroxidase. They exhibit, however, some DPNH – cytochrome c reductase activity which is believed to be quite independent of the DPNH oxidase system. The extracts are devoid of cytochrome c oxidase activity although they contain a respiratory system which readily oxidizes p-phenylenediamine.

scholarly journals Inhibitory effects of some long-chain unsaturated fatty acids on mitochondrial β-oxidation. Effects of streptozotocin-induced diabetes on mitochondrial β-oxidation of polyunsaturated fatty acids

1985 ◽  
Vol 230 (2) ◽  
pp. 329-337 ◽  
Author(s):  
H Osmundsen ◽  
K Bjørnstad
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Reductase Activity ◽  
Liver Mitochondria ◽  
Inhibitory Effect ◽  
Diabetic Rats ◽  
Inhibitory Property ◽  
Streptozotocin Induced Diabetes ◽  
Streptozotocin Diabetic Rats ◽  
Coa Reductase

Evidence showing that some unsaturated fatty acids, and in particular docosahexaenoic acid, can be powerful inhibitors of mitochondrial β-oxidation is presented. This inhibitory property is, however, also observed with the cis- and trans-isomers of the C18:1(16) acid. Hence it is probably the position of the double bond(s), and not the degree of unsaturation, which confers the inhibitory property. It is suggested that the inhibitory effect is caused by accumulation of 2,4-di- or 2,4,7-tri-enoyl-CoA esters in the mitochondrial matrix. This has previously been shown to occur with these fatty acids, in particular when the supply of NADPH was limiting 2,4-dienoyl-CoA reductase (EC 1.3.1.-) activity [Hiltunen, Osmundsen & Bremer (1983) Biochim. Biophys. Acta 752, 223-232]. Liver mitochondria from streptozotocin-diabetic rats showed an increased ability to β-oxidize 2,4-dienoyl-CoA-requiring acylcarnitines. Docosahexaenoylcarnitine was also found to be less inhibitory at lower concentrations with incubation under coupled conditions. With uncoupling conditions there was little difference between mitochondria from normal and diabetic rats in these respects. This correlates with a 5-fold stimulation of 2,4-dienoyl-CoA reductase activity found in mitochondria from streptozotocin-diabetic rats.

scholarly journals Energy metabolism in the pancreas of ground squirrels (Spermophilus citellus) during prolonged cold exposure and in hibernation

2021 ◽  
Vol 62 (1) ◽  
pp. 44-49
Author(s):  
Aleksandra Janković ◽  
Anđelika Kalezić ◽  
Strahinja Đurić ◽  
Aleksandra Korać ◽  
Biljana Buzadžić ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Cold Exposure ◽  
Expression Profiles ◽  
Oxidative Capacity ◽  
Ground Squirrels ◽  
Control Group ◽  
Antioxidative Defence ◽  
Nuclear Respiratory Factor ◽  
Metabolic Remodeling ◽  
Spermophilus Citellus

Mammalian hibernators undergo a host of biochemical adaptations that allow them to survive the harsh cold environment and food restriction. Since the energy metabolism of the pancreas during hibernation remains unknown, we investigated the molecular basis of mitochondrial energy-producing pathways in line with their regulating mechanisms, as well as the (re)organization of antioxidative defence in the pancreas during the prehibernation period and in the hibernating state. To this end, male ground squirrels (Spermophilus citellus) were divided into two groups, the control group kept at room temperature (22±1 °C) and the group exposed to low temperature (4±1 °C). Active animals from the cold exposed group were sacrificed after 1, 3, 7, 12, and 21 days; animals that entered hibernation were sacrificed after 2-5 days of torpor. Our results showed that the protein levels of respiratory complexes I, II, IV and cytochrome c were increased in response to prolonged cold exposure (from day 12) and that such expression profiles were maintained during hibernation. In parallel, AMP-activated protein kinase a (AMPKa) and nuclear respiratory factor 1 (NRF-1) were shown to be upregulated. Moreover, prolonged cold exposure and hibernation induced an increase in the protein expression of antioxidative defence enzymes copper-zinc superoxide dismutase (CuZnSOD) and glutathione peroxidase (GSH-Px). In conclusion, these results point to a controlled metabolic remodeling in the pancreas of ground squirrels during prolonged cold exposure and in hibernation, which includes an improvement of mitochondrial oxidative capacity along with a proportional upregulation of antioxidative defence.

scholarly journals Epigallocatechin-3-Gallate (EGCG), An Active Constituent of Green Tea: Implications in the Prevention of Liver Injury Induced by Diethylnitrosamine (DEN) in Rats

2019 ◽  
Vol 9 (22) ◽  
pp. 4821 ◽  
Author(s):  
Saleh A. Almatroodi ◽  
Mohammed A. Alsahli ◽  
Hanan Marzoq Alharbi ◽  
Amjad Ali Khan ◽  
Arshad Husain Rahmani
Keyword(s):  
Cell Cycle ◽  
Liver Injury ◽  
Green Tea ◽  
Liver Toxicity ◽  
Oxidative Capacity ◽  
Oxidative Enzymes ◽  
Control Group ◽  
Active Constituent ◽  
Drug Induced ◽  
Oxidative Potential

Liver diseases are one of the most detrimental conditions that may cause inflammation, leading to tissue damage and perturbations in functions. Several drugs are conventionally available for the treatment of such diseases, but the emergence of resistance and drug-induced liver injury remains pervasive. Hence, alternative therapeutic strategies have to be looked upon. Epigallocatechin-3-gallate (EGCG) is a naturally occurring polyphenol in green tea that has been known for its disease-curing properties. In this study, we aimed to evaluate its anti-oxidative potential and protective role against diethylnitrosamine (DEN)-induced liver injury. Four different groups of rats were used for this study. The first group received normal saline and served as the control group. The second group received DEN (50 mg/kg body wt) alone and third group received DEN plus EGCG (40 mg/kg body wt) only. The fourth group were treated with EGCG only. The liver protective effect of EGCG against DEN toxicity through monitoring the alterations in aspartate transaminase (AST), and alanine transaminase (ALT) and alkaline phosphatase (ALP) activities, serum level of pro-inflammatory mediators and anti-oxidant enzymes, histopathological alterations, measurement of cellular apoptosis, and cell cycle analysis was examined. The rats that were given DEN only had a highly significantly elevated levels of liver enzymes and pro-inflammatory cytokines, highly decreased anti-oxidative enzymes, and histological changes. In addition, a significant elevation in the percentage of apoptotic nuclei and cell cycle arrest in the sub- G1 phase was detected. EGCG acts as a hepatoprotectant on DENs by reducing the serum levels of liver functional enzymes, increasing total anti-oxidative capacity, reducing pathological changes and apoptosis, as well as causing the movement of cells from the sub G1 to S or G2/M phase of the cell cycle. In conclusion, EGCG displayed a powerful hepatoprotective additive as it considerably mitigates the liver toxicity and apoptosis induced by DEN.

Hepatic function of the golden hamster after exposure to cold and during hibernation

1959 ◽  
Vol 196 (4) ◽  
pp. 910-912
Author(s):  
Joseph D. Harrington ◽  
Roland M. Nardone
Keyword(s):  
Liver Function ◽  
Cold Exposure ◽  
Golden Hamster ◽  
Blood Clotting ◽  
Hepatic Function ◽  
Clotting Time ◽  
Liver Impairment ◽  
Flocculation Test

The effect of forced hypothermia, long term cold exposure and hibernation on liver function of the golden hamster, Mesocricetus auratus, was studied in order to ascertain the role of the liver in survival of a hibernator under cold stress. The bromsulphalein test for liver function indicated no liver damage from forced hypothermia and 3.5% liver impairment from long term cold exposure. The colloidal red flocculation test for liver function showed an upset of serum albumin/globulin ratio after long cold exposure and during hibernation. This is correlated with prolongation of blood clotting time observed during hibernation. These factors are used to exemplify the importance of the liver in hibernal physiology.

Sign in / Sign up

Export Citation Format

Share Document