Amino acids and growth of the pregnant uterus

Williams, John M.; Needham, Dorothy M.

doi:10.1042/bj0900489

Cited by 2 publications

(2 citation statements)

References 22 publications

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“…As shown in Fig. 6, the difference spectrum of the crude ghost fraction is the same as that found with intact mitochondria (29). No cytochromes were detected in washes I, II, or III.…”

Section: Cytochromessupporting

confidence: 53%

“…Cytochromes a, b, cl, and c in the various fractions were estimated by the spectral method of Williams (29), with a Carey Model 15 recording spectrophotometer adjusted so that the full range of the recorder measured 0.0 to 0.1 optical density units. Lipids were extracted into chloroform-methanol by a modification of the procedure of Folch et al (32).…”

Section: Electron Microscopymentioning

confidence: 99%

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Biochemical and Ultrastructural Properties of Osmotically Lysed Rat-Liver Mitochondria

Caplan¹,

Greenawalt²

1966

The Journal of Cell Biology

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Isolated rat-liver mitochondria were osmotically lysed by suspension and washing 3 times in cold, distilled water. Pellets obtained by centrifugation at 105,000 g for 30 rain were resuspended, fixed with glutaraldehyde and OsO4, and embedded in Epon 812. Thin seetions show the presence of two distinct membranous populations, each of which is relatively homogeneous in size and appearance. Swollen mitochondria (~1.5 g in diameter), which have been stripped of their outer membranes, are largely devoid of matrix and normal matrix granules and are referred to as "ghosts." The smaller (0.2 to 0.4/z in diameter), empty appearing, vesicular elements, derived primarily from the outer mitochondrial membrane, can be differentiated from the ghosts on the basis of their smaller size and complete absence of internal structures, especially cristae. Each membranous element is enclosed by a single, continuous membrane; the "double membrane" organization typical of intact mitochondria is not observed. These findings indicate that the outer membrane of rat-liver mitochondria is spatially dissociated from the inner mitochondrial membrane by osmotic lysis of the mitochondria in distilled water.Three parameters of structural and functional significance in freshly isolated rat-liver mitochondria have been correlated with the structural alterations observed: (a) chemical composition (total protein, lipid phosphate and total phosphate), (b) specific and total activities of marker enzymes for mitochondrial matrix and membranes (malate dehydrogenase (MDH), D-/3-hydroxybutyrate dehydrogenase (BDH) and cytochromes), and (c) integrated multienzyme functions (respiration, phosphorylation, and contraction). The data presented indicate that all rnitochondrial membranes are completely conserved in the crude ghost preparation and that, in addition, about 1/~ of the matrix proteins (estimated by assays for MDH activity and protein) are retained. The study of integrated mitochondrial functions shows that a number of physiologically important multienzyme activities also are preserved in the water-washed preparation. The respiratory rate of ghosts per milligram of protein is 1.5 to 2.0 times that of intact mitochondria, which shows that the respiratory chain in the ghosts is functionally intact. The rate of phosphorylation is reduced, however, to about 25 % of that measured in freshly isolated mitochondria and accounts for lowered P : O ratios using succinate as substrate (P : O ranges from o. 4 to o.9). The phosphorylation of ADP to ATP is the only biochemical function, so far investigated, that is greatly affected by osmotic lysis. In addition, two lines of evidence suggest that the ghosts undergo an energy-dependent transformation resulting in contraction: (a) suspensions of the crude ghost preparation in 0.02 M Tris-0.125 M KCI medium show a marked increase

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“…As shown in Fig. 6, the difference spectrum of the crude ghost fraction is the same as that found with intact mitochondria (29). No cytochromes were detected in washes I, II, or III.…”

Section: Cytochromessupporting

confidence: 53%

Section: Electron Microscopymentioning

confidence: 99%