scholarly journals Electron Microscopic Radioautographic Study on Protein Synthesis in Hepatocyte Mitochondria of Aging Mice

2006 ◽  
Vol 6 ◽  
pp. 1583-1598 ◽  
Author(s):  
Tetsuji Nagata
Keyword(s):  
Protein Synthesis ◽  
Labeling Index ◽  
Electron Microscopic ◽  
Protein Precursor ◽  
Mouse Hepatocytes ◽  
Development And Aging ◽  
Silver Grains ◽  
Liver Tissues

For the purpose of studying the aging changes of intramitochondrial protein synthesis in mouse hepatocytes, 10 groups of aging mice, each consisting of 3 individuals (total 30), from fetal day 19 to postnatal month 24, were injected during development with 3H-leucine, a protein precursor, sacrificed 1 h later, and the liver tissues processed for electron microscopic (EM) radioautography. On EM radioautograms obtained from each animal, the number of mitochondria, the number of labeled mitochondria, and the mitochondrial labeling index labeled with silver grains due to3H-leucine showing protein synthesis in each mononucleate hepatocytes were counted and the averages in respective aging groups were compared. From the results, it was demonstrated that the numbers of mitochondria, the numbers of labeled mitochondria, and the labeling indices of intramitochondrial protein syntheses in mononucleate hepatocytes of mice at various ages from embryonic day 19 to postnatal month 24 increased and decreased due to development and aging of animals.

scholarly journals Electron Microscopic Radioautographic Study on Protein Synthesis in Mitochondria of Binucleate Hepatocytes of Aging Mice

2007 ◽  
Vol 7 ◽  
pp. 1008-1023 ◽  
Author(s):  
Tetsuji Nagata
Keyword(s):  
Protein Synthesis ◽  
Labeling Index ◽  
Electron Microscopic ◽  
Protein Precursor ◽  
Binucleate Cells ◽  
Mouse Hepatocytes ◽  
Electron Microscopic Radioautography ◽  
Liver Tissues

In order to study the aging changes of intramitochondrial protein synthesis in mouse hepatocytes, 10 groups of aging mice, each consisting of three individuals, total 30, from fetal day 19 to postnatal year 2, were injected with3H-leucine, a protein precursor, sacrificed 1 h later, and the liver tissues processed for electron microscopic radioautography. On electron microscopic radioautograms obtained from each animal, the numbers of mitochondria, the numbers of labeled mitochondria, and the mitochondrial labeling index labeled with3H-leucine that showed protein synthesis in each hepatocyte, both mononucleate and binucleate cells, were counted and the averages in respective aging groups were compared. From the results, it was demonstrated that the numbers of mitochondria, the numbers of labeled mitochondria, and the labeling indices of intramitochondrial protein syntheses in both mononucleate and binucleate hepatocytes of mice at various ages increased due to development of animals. The numbers of mitochondria, the numbers of labeled mitochondria, and the labeling indices of intramitochondrial protein synthesis in binucleate hepatocytes were more than those of mononucleate hepatocytes at the same aging stages.

scholarly journals Electron Microscopic Radioautographic Study on Mitochondrial DNA Synthesis in Adrenal Cortical Cells of Developing and Aging Mice

2008 ◽  
Vol 8 ◽  
pp. 683-697 ◽  
Author(s):  
Tetsuji Nagata
Keyword(s):  
Dna Synthesis ◽  
Cortical Cell ◽  
Zona Glomerulosa ◽  
Labeling Index ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Development And Aging ◽  
Adrenal Cortical Cells ◽  
Mitochondrial Dna Synthesis ◽  
Developing Mice

In order to study the aging changes of intramitochondrial DNA synthesis of mouse adrenal cortical cells, eight groups of developing mice, each consisting of three individuals (total 24), from fetal day 19 to postnatal newborn at days 1, 3, 9, 14, to adult at months 1, 2, and 6, were injected with3H-thymidine, sacrificed 1 h later, and the adrenal tissues were fixed and processed for electron microscopic (EM) radioautography. On EM radioautograms obtained from each animal, the number of mitochondria and the mitochondrial labeling index labeled with3H-thymidine showing DNA synthesis in each adrenal cortical cell, in three zones, were counted and the results in respective developing groups were compared. From the results, it was demonstrated that the numbers of mitochondria in the three zones, the zona glomerulosa, fasciculata, and reticularis, of mice at various ages increased from fetal day 19 to postnatal month 6 due to development and aging of animals, respectively, while the number of labeled mitochondria and the labeling index of intramitochondrial DNA syntheses incorporating3H-thymidine increased from fetal day 19 to postnatal month 2, reaching the maxima, and decreased to month 6. It was shown that the activity of intramitochondrial DNA synthesis in the adrenal cortical cells in developing and aging mice changed due to aging.

Distribution of newly formed hepatic glycogen in adrenalectomized rats as observed by radioautography after injection of 3H-galactose

1984 ◽  
Vol 42 ◽  
pp. 228-229
Author(s):  
J. E. Michaels ◽  
J. T. Hung ◽  
E. L. Cardell ◽  
R. R. Cardell
Keyword(s):  
Glycogen Synthesis ◽  
Hepatic Glycogen ◽  
Electron Microscopic ◽  
Routine Procedures ◽  
Silver Grains ◽  
Synthetic Glucocorticoid ◽  
Adrenalectomized Rats

In order to study early events of glycogen synthesis, we have used adrenalectomized (ADX) rats fasted overnight and injected with the synthetic glucocorticoid dexamethasone (DEX) to stimulate glycogen synthesis. Rats were given DEX 0-5 hr prior to sacrifice and injected with 2 mCi 3H-galactose 1 hr prior to sacrifice. Liver was prepared for light (LM) and electron microscopic (EM) radioautography by routine procedures.The concentration of silver grains over hepatic cytoplasm was measured in LM radioautographs using a Zeiss Videoplan. The hepatocytes were categorized as unlabeled if no silver grains (gr) were present, lightly labeled (<10gr/100 μm2 cytoplasm) or intensely labeled (>10 gr/1002 μm cytoplasm). Although very few hepatocytes showed heavy labeling after 1 hr treatment with DEX, by 2 hr after DEX treatment 8% of the cells distributed throughout the lobule were intensely labeled.

Milk Protein Precursors in the Goat During Late Lactation

1993 ◽  
Vol 1993 ◽  
pp. 1-1
Author(s):  
B.J. Bequette ◽  
F.R.C. Backwell ◽  
A.G. Calder ◽  
J.A. Metcalf ◽  
D. Wray-Cahen ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Mammary Gland ◽  
Milk Protein ◽  
Protein S ◽  
Dairy Goats ◽  
Protein Precursor ◽  
Previous Hypothesis ◽  
Casein Protein ◽  
Isotope Kinetics

Previously, we have reported on work in dairy goats using stable isotope kinetics to examine the precursors for milk protein synthesis (1). Contrary to a previous hypothesis (2), these results suggested that blood free amino acids (AA) are not simply transported into the mammary gland and incorporated directly into milk protein. Although the latter may still occur, a substantial amount of the AA for milk protein synthesis appears to be channelled through constitutive mammary gland protein(s) first. Moreover, the data indicated that a proportion (12-20%) of the casein protein precursor may be derived from extra-mammary sources other than blood free AA, e.g. peptides and/or proteins. It may be possible therefore to alter milk protein synthesis by the provision of different forms of precursor amino acids. Since the previous study was in goats during early lactation (day 61 ± 11), the present study reports on the precursors for milk protein synthesis in goats during late lactation, and allows a comparison between stages of lactation.

RENAL UPTAKE AND METABOLISM OF ADRENOCORTICOTROPHIN ANALOGUES IN THE RAT: AN AUTORADIOGRAPHIC STUDY

1977 ◽  
Vol 74 (1) ◽  
pp. 23-35 ◽  
Author(s):  
J. R. J. BAKER ◽  
H. P. J. BENNETT ◽  
R. A. CHRISTIAN ◽  
C. McMARTIN
Keyword(s):  
Autoradiographic Study ◽  
Proximal Tubules ◽  
Tyrosine Residue ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Renal Uptake ◽  
Endocytotic Vesicles ◽  
Silver Grains ◽  
Uptake And Metabolism

Renal resorption of tritiated adrenocorticotrophin analogues was studied in the rat using light microscopic and quantitative electron microscopic autoradiography. The synthetic corticotrophins used were Synacthen (corticotrophin-(1–24)-tetracosapeptide) and C 41795-Ba ([D-Ser1,Lys17,Lys18]-corticotrophin-(1–18)-octadecapeptide amide), the tetracosapeptide being tritiated in either the tyrosine residue of position 2 or 23 or the phenylalanine of position 7 and the octadecapeptide in the tyrosine of position 2. Inspection of autoradiographs showed that peptides injected intravenously were resorbed into proximal tubules by endocytosis to produce vesicles whose radiolabel later appeared in lysosomes, a route previously elucidated for other peptides and proteins. The use of two techniques for analysis of electron microscopic autoradiographs, however, suggested that apical tubules also acquire label and are in some way involved in the transfer of resorbed labelled material from endocytotic vesicles to lysosomes. In addition, the autoradiographic analyses revealed that the duration of lysosomal labelling depends upon the position of tritium in the chain. Thus, when the CO2H-terminus of Synacthen was labelled, silver grains were more transiently associated with lysosomes than was the case when the NH2-terminal or core regions were tritiated, indicating a greater resistance of these portions of the peptide to attack by intracellular peptidase. The label from the chemically protected C 41795-Ba was also less readily expelled from the lysosomes of the proximal tubules.

scholarly journals NUCLEAR ENVELOPE-ASSOCIATED RESUMPTION OF RNA SYNTHESIS IN LATE MITOSIS OF HELA CELLS

1973 ◽  
Vol 59 (1) ◽  
pp. 150-164 ◽  
Author(s):  
T. Simmons ◽  
P. Heywood ◽  
L. Hodge
Keyword(s):  
Protein Synthesis ◽  
Nuclear Envelope ◽  
Rna Synthesis ◽  
Electron Microscope Autoradiography ◽  
Molecular Synthesis ◽  
Hela S3 ◽  
Precursor Rna ◽  
Ribosomal Precursor ◽  
Hela S3 Cells ◽  
Silver Grains

The restitution of RNA synthesis in cultures progressing from metaphase into interphase (G1) has been investigated in synchronized HeLa S3 cells by using inhibitors of macro-molecular synthesis and the technique of electron microscope autoradiography. The rate of incorporation of radioactive uridine into RNA approached interphase levels in the absence of renewed protein synthesis. In contrast, maintenance of this rate in G1 was dependent upon renewed protein synthesis. Restoration of synthesis of heterogeneous nuclear RNA occurred under conditions that inhibited production of ribosomal precursor RNA. In autoradiographs of individual cells exposed to radioactive uridine, silver grains were first detected after nuclear envelope reformation at the periphery of the chromosome mass but before chromosomal decondensation. These data are consistent with the following interpretation. Multiple RNA polymerase activities persist through mitosis and are involved in the initiation of RNA synthesis in early telophase at sites on the nuclear envelope.

scholarly journals LIGHT AND ELECTRON MICROSCOPIC RADIOAUTOGRAPHY OF HEPATIC CELL NUCLEOLI IN MICE TREATED WITH ACTINOMYCIN D

1967 ◽  
Vol 33 (3) ◽  
pp. 489-496 ◽  
Author(s):  
J. C. H. de Man ◽  
N. J. A. Noorduyn
Keyword(s):  
Orotic Acid ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Electron Microscopic ◽  
Granular Component ◽  
Hepatic Cells ◽  
Progressive Loss ◽  
Nucleolar Rna ◽  
Silver Grains ◽  
Electron Microscopic Radioautography

Nucleolar partition induced by actinomycin D was used to demonstrate some aspects of nucleolar RNA synthesis and release in mouse hepatic cells, with light and electron microscopic radioautography. The effect of the drug on RNA synthesis and nucleolar morphology was studied when actinomycin D treatment preceded labeling with tritiated orotic acid. Nucleolar partition, consisting of a segegration into granular and fibrillar parts was visible if a dosage of 25 µg of actinomycin D was used, but nucleolar RNA was still synthesized. After a dosage of 400 µg of actinomycin D, nucleolar RNA synthesis was completely stopped If labeling with tritiated orotic acid preceded treatment with 400 µg of actinomycin D, labeled nucleolar RNA was present 15 min after actinomycin D treatment while high resolution radioautography showed an association of silver grains with the granular component. At 30 min after actinomicyn D treatment all labeling was lost. Since labeling was associated with the granular component the progressive loss of label as a result of actinomycin D treatment indicated a release of nucleolar granules. The correlation between this release and the loss of 28S RNA from actinomycin D treated nucleoli as described in the literature is discussed.

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