STRUCTURAL CHANGES ASSOCIATED WITH THE RELEASE OF ENZYMES FROM RAT-LIVER MITOCHONDRIA BY FREEZING

1966 ◽  
Vol 44 (6) ◽  
pp. 775-781 ◽  
Author(s):  
C. V. Lusena ◽  
C. M. S. Dass
Keyword(s):  
Rat Liver ◽  
Structural Modification ◽  
Structural Changes ◽  
Sodium Deoxycholate ◽  
Liver Mitochondria ◽  
Maximum Activity ◽  
Supernatant Fraction ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Disruption ◽  
Partial Release

Suspensions of rat-liver mitochondria in 0.44 M sucrose, after they were frozen and thawed under defined conditions, were partitioned into three sedimentable and one supernatant fraction by differential centrifugation. These were analyzed for optical density, protein content, and for activities of glutamate dehydrogenase (GD) and 3-hydroxybutyrate dehydrogenase (BD) with exogenous nicotinamide–adenine dinucleotide (NAD) both as maximum activity after sodium deoxycholate treatment and as activity released by freezing. Pellets of the three sedimentable fractions were also examined in the electron microscope. When dehydrogenases were not released by a freezing treatment, no structural changes were detected. Release of BD, which was accompanied by release of GD as well, was associated with mitochondrial disruption and drastic rearrangement of mitochondrial membranes. On the other hand, release of GD without BD occurred from swollen and emptied mitochondria. The partial release of enzymes in a preparation was not associated with a partial structural modification of all of the mitochondria, but rather with drastic structural changes in only some of them.

scholarly journals Two forms of aspartate aminotransferase in rat liver and kidney mitochondria

1968 ◽  
Vol 108 (4) ◽  
pp. 619-624 ◽  
Author(s):  
M. M. Bhargava ◽  
A. Sreenivasan
Keyword(s):  
Rat Liver ◽  
Aspartate Aminotransferase ◽  
High Speed ◽  
Rat Kidney ◽  
Liver Mitochondria ◽  
Supernatant Fraction ◽  
Rat Liver Mitochondria ◽  
Aminotransferase Activity ◽  
Kidney Mitochondria ◽  
Liver And Kidney

1. Butan-1-ol solubilizes that portion of rat liver mitochondrial aspartate aminotransferase (EC 2.6.1.1) that cannot be solubilized by ultrasonics and other treatments. 2. A difference in electrophoretic mobilities, chromatographic behaviour and solubility characteristics between the enzymes solubilized by ultrasonic treatment and by butan-1-ol was observed, suggesting the occurrence of two forms of this enzyme in rat liver mitochondria. 3. Half the aspartate aminotransferase activity of rat kidney homogenate was present in a high-speed supernatant fraction, the remainder being in the mitochondria. 4. A considerable increase in aspartate aminotransferase activity was observed when kidney mitochondrial suspensions were treated with ultrasonics or detergents. 5. All the activity after maximum activation was recoverable in the supernatant after centrifugation at 105000g for 1hr. 6. The electrophoretic mobility of the kidney mitochondrial enzyme was cathodic and that of the supernatant enzyme anodic. 7. Cortisone administration increased the activities of both mitochondrial and supernatant aspartate aminotransferases of liver, but only that of the supernatant enzyme of kidney.

scholarly journals Morphological changes of mitochondria and mammalian cells, induced by hypochlorous acid

2019 ◽  
Vol 64 (2) ◽  
pp. 156-168
Author(s):  
I. B. Zavodnik ◽  
R. I. Kravchuk ◽  
T. V. Ilyich ◽  
E. A. Lapshina ◽  
A. G. Vejko ◽  
...  
Keyword(s):  
Rat Liver ◽  
Mammalian Cells ◽  
Structural Changes ◽  
Hypochlorous Acid ◽  
Morphological Changes ◽  
Liver Mitochondria ◽  
Hill Coefficient ◽  
Rat Liver Mitochondria ◽  
Apparent Dissociation Constant ◽  
Functional Changes

Hypochlorous acid, HOCl, is one of the most powerful biological oxidants and the most important mediator of inflammatory damage of cells and tissues. The purpose of this study was to characterize the morphological features of HOCl – induced oxidative impairment in rat liver mitochondria in vitro and to compare the processes of HOCl-induced oxidation in mitochondria, erythrocytes and B14 cells.HOCl addition (300 μM) to mitochondrial suspension resulted in mitochondrial structural changes with a decrease in the mean total length of the crista and the average number of cristae in one mitochondria with no change in the length of one crista. There was shown a slight decrease in the average cross-sectional area of one mitochondria, mitochondrial profile elongation, an increase in the number of altered mitochondria and the heterogeneity of the population. Simultaneously we observed depolarization of the mitochondrial membrane, the rate and degree of which were determined by the concentration of HOCl. HOCl addition (25–150 μМ) induced lysis of erythrocytes for 60–180 s, which was preceded by a change in the shape and size of cells. The apparent dissociation constant for the HOCl – membrane complex was estimated to be Kd = 140 ± 25 μМ, and the Hill coefficient was to be 2.1. The B14 cell exposure to HOCl (100 μМ) led to a loss of ability to sorb on the substrate, to form associates, and to subsequent shrinkage of cells.Therefore, HOCl caused some morphological (and functional) changes in rat liver mitochondria, which may serve as one of the causes of cell death in inflammatory foci. At the level of the whole cells, the HOCl addition induced lysis of red blood cells and deep damage to B14 cells.

scholarly journals Translocation to rat liver mitochondria of phosphatidate phosphohydrolase

1989 ◽  
Vol 263 (2) ◽  
pp. 589-595 ◽  
Author(s):  
M Freeman ◽  
E H Mangiapane
Keyword(s):  
Outer Membrane ◽  
Rat Liver ◽  
Liver Lipid ◽  
Experimental System ◽  
Liver Mitochondria ◽  
Membrane Preparation ◽  
Supernatant Fraction ◽  
Mitochondrial Outer Membrane ◽  
Rat Liver Mitochondria ◽  
Phosphatidate Phosphohydrolase

When a particle-free supernatant fraction from rat liver was incubated at 37 degrees C with mitochondria and oleate, some of the enzyme phosphatidate phosphohydrolase (PAP), initially present in the particle-free supernatant, was recovered, after the incubation, bound to mitochondria. This translocation of PAP from cytosol to mitochondria was stimulated by oleate or palmitate in a similar fashion to the stimulation of translocation of PAP to endoplasmic reticulum [Martin-Sanz, Hopewell & Brindley (1984) FEBS Lett. 175, 284-288]. Translocation of PAP from particle-free supernatant to a partially purified mitochondrial-outer-membrane preparation was also stimulated by oleate. More PAP was bound to a mitochondrial-outer-membrane fraction washed in 0.5 M-NaCl before resuspension in sucrose than to a sucrose-washed mitochondrial-outer-membrane preparation. In contrast, washing of microsomal membranes in 0.5 M-NaCl did not enhance the binding of PAP to these membranes. PAP also binds to phosphatidate-loaded mitochondria or microsomes (microsomal fractions). In the experimental system employed, more PAP bound to mitochondria loaded with phosphatidate than to microsomes loaded with phosphatidate. The results are discussed in relation to the role of mitochondrial phosphatidate in liver lipid metabolism.

Effects of 5-5'-Diphenyl-2-thiohydantoin (DPTH) and Thyroxine on the Ultrastructure and Chemical Composition of Rat Liver

1971 ◽  
Vol 29 ◽  
pp. 570-571
Author(s):  
E. A. Elfont ◽  
R. B. Tobin ◽  
D. G. Colton ◽  
M. A. Mehlman
Keyword(s):  
Chemical Composition ◽  
Rat Liver ◽  
Future Study ◽  
Mode Of Action ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Effective Inhibitor ◽  
Biochemical Effects ◽  
Glycerophosphate Dehydrogenase ◽  
Stimulation Of

Summary5,-5'-diphenyl-2-thiohydantoin (DPTH) is an effective inhibitor of thyroxine (T4) stimulation of α-glycerophosphate dehydrogenase in rat liver mitochondria. Because this finding indicated a possible tool for future study of the mode of action of thyroxine, the ultrastructural and biochemical effects of DPTH and/or thyroxine on rat liver mere investigated.Rats were fed either standard or DPTH (0.06%) diet for 30 days before T4 (250 ug/kg/day) was injected. Injection of T4 occurred daily for 10 days prior to sacrifice. After removal of the liver and kidneys, part of the tissue was frozen at -50°C for later biocheailcal analyses, while the rest was prefixed in buffered 3.5X glutaraldehyde (390 mOs) and post-fixed in buffered 1Z OsO4 (376 mOs). Tissues were embedded in Araldlte 502 and the sections examined in a Zeiss EM 9S.Hepatocytes from hyperthyroid rats (Fig. 2) demonstrated enlarged and more numerous mitochondria than those of controls (Fig. 1). Glycogen was almost totally absent from the cytoplasm of the T4-treated rats.

Energy and Antioxidant Status of Rat Liver Mitochondria during Hypoxia- Reoxygenation of Different Duration

2016 ◽  
Vol 7 (4) ◽  
pp. 349-361
Author(s):  
Olga A. Gonchar ◽  
Valentina I. Nosar ◽  
Larisa. V. Bratus ◽  
I. N. Tymchenko ◽  
N. N. Steshenko ◽  
...  
Keyword(s):  
Rat Liver ◽  
Antioxidant Status ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Hypoxia Reoxygenation
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