scholarly journals AUTORADIOGRAPHIC STUDY OF DNA SYNTHESIS AND THE CELL CYCLE IN SPERMATOGONIA AND SPERMATOCYTES OF MOUSE TESTIS USING TRITIATED THYMIDINE

1962 ◽  
Vol 14 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Valerio Monesi
Keyword(s):  
Dna Synthesis ◽  
Time Course ◽  
Average Duration ◽  
Tritiated Thymidine ◽  
Periodic Acid ◽  
Autoradiographic Study ◽  
Type B ◽  
Average Life ◽  
Periodic Acid Schiff ◽  
Average Life Span

Mice were injected intraperitoneally with 15 µc of H3-thymidine. The time course of the labeling in spermatogonia and spermatocytes was studied by using autoradiography on 5 µ sections stained by the periodic acid-Schiff method and hematoxylin over a period of 57 hours after injection. Four generations of type A (called AI, AII, AIII, and AIV), one of intermediate, and one of type B spermatogonia occur in one cycle of the seminiferous epithelium. The average life span is about the same in all spermatogonia, i.e., about 27 to 30.5 hours. The average pre-DNA synthetic time, including the mitotic stages from metaphase through telophase and the portion of interphase preceding DNA synthesis, is also not very different, ranging between 7.5 and 10.5 hours. A remarkable difference exists, however, in the duration of DNA synthesis and of the post-DNA synthetic period. The average DNA synthetic time is very long and is highly variable in type B (14.5 hours), a little shorter and less variable in intermediate (12.5 hours) and AIV (13 hours) spermatogonia, and much shorter and very constant in AIII (8 hours), AII and AI (7 to 7.5 hours) spermatogonia. Conversely, the average post-DNA synthetic time, corresponding essentially to the duration of the prophase, is short and very constant in type B (4.5 hours), longer and variable in intermediate (6 hours) and AIV (8 hours) spermatogonia, and much longer and much more variable in AIII (11 hours), AII and AI (14 hours) spermatogonia. The premeiotic synthesis of DNA takes place in primary spermatocytes during the resting phase and terminates just before the visible onset of the meiotic prophase. Its average duration is 14 hours. No further synthesis of DNA takes place in later stages of spermatogenesis.

The development of the tectum in Xenopus laevis: an autoradiographic study

Development ◽  
1972 ◽  
Vol 28 (1) ◽  
pp. 87-115
Author(s):  
K. Straznicky ◽  
R. M. Gaze
Keyword(s):  
Xenopus Laevis ◽  
Dna Synthesis ◽  
Optic Tectum ◽  
Tritiated Thymidine ◽  
Dorsal Surface ◽  
Autoradiographic Study ◽  
Cell Type ◽  
Pole Cells ◽  
Serial Addition ◽  
The Times

The development of the optic tectum in Xenopus laevis has been studied by the use of autoradiography with tritiated thymidine. The first part of the adult tectum to form is the rostroventral pole; cells in this position undergo their final DNA synthesis between stages 35 and 45 or shortly thereafter. Next, the cells comprising the ventrolateral border of the tectum form. These cells undergo their final DNA synthesis at or shortly after stage 45. Finally the cells comprising the dorsal surface of the adult tectum form, mainly between stages 50–55. This part of the tectum originates from the serial addition of strips of cells medially, which displace the pre-existing tissue laterally and rostrally. The formation of the tectum is virtually complete by stage 58. The tectum in Xenopus thus forms in topographical order from rostroventral to caudo-medial. The distribution of labelled cells, several stages after the time of injection of isotope, indicates that, at any one time, a segment of tectum is forming which runs normal to the tectal surface and includes all layers from the ventricular layer out to the surface. In Xenopus, therefore, the times of origin of tectal cells appear to be related not to cell type or tectal layer but to the topographical position of the cells across the surface of the tectum.

Studies on the Autonomy of Pellicular DNA in Paramecium

1969 ◽  
Vol 5 (2) ◽  
pp. 365-372
Author(s):  
JOAN SMITH-SONNEBORN ◽  
W. PLAUT
Keyword(s):  
Dna Synthesis ◽  
Tritiated Thymidine ◽  
Autoradiographic Study ◽  
Sensitive Material ◽  
Selective Labelling ◽  
The Relationship

This autoradiographic study was designed to elucidate the relationship between the macronucleus and pellicular DNA in Paramecium. The capacity of the cell to synthesize pellicular DNA in the absence of the macronucleus was established by demonstrating the incorporation of tritiated thymidine into DNase-sensitive material in the pellicles of amacronucleate cells. Moreover, using a technique which leads to selective labelling of the macronucleus in normal paramecia, we have looked for evidence of transfer of labelled DNA from the macronucleus to the pellicle with time. Finding none, we conclude that labelled pellicular DNA is not of macronuclear origin, and that labelled pellicular DNA synthesis is not directly dependent on the presence of the macronucleus.

scholarly journals Histochemical and Autoradiographic Studies on the Effects of Aging on the Mucopolysaccharides of the Periosteum

1959 ◽  
Vol 6 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Edgar A. Tonna ◽  
Eugene P. Cronkite
Keyword(s):  
Chondroitin Sulfate ◽  
Toluidine Blue ◽  
Bone Growth ◽  
Periodic Acid ◽  
Neutral Type ◽  
Autoradiographic Study ◽  
Colloidal Iron ◽  
Periodic Acid Schiff ◽  
Schiff Reaction ◽  
Effects Of Aging

An autoradiographic study was made using S35-sulfate for the localization, distribution, and variation in the mucopolysaccharide content of the femoral periosteum of rats from birth to old age. The mucopolysaccharides were also studied histochemically, using toluidine blue O, Rinehart and Abu'l-Haj's colloidal iron method, and the periodic acid-Schiff reaction, before and after hyaluronidase treatment. Autoradiograms revealed the uptake of S35 particularly in the vicinity of the preosseous zone and adjacent osteoblasts. This labelling was highest at the period of rapid bone growth. With increasing age, the S35 uptake became progressively less. The preosseous zone showed γ-metachromatic staining at all ages after treatment with toluidine blue. Active osteoblasts were mostly orthochromatic, however, ß-metachromasia was exhibited at a later age. Abundant amounts of intra- and extracellular mucopolysaccharides of both the acid and neutral type were demonstrated in the periosteum. S35 uptake and γ-metachromasia show the presence of sulfated mucopolysaccharides, of which chondroitin sulfate predominates in the preosseous zone. Since S35 uptake is high in active osteoblasts, the inability to demonstrate metachromasia in osteoblasts may indicate either that chondroitin sulfate is liberated as fast as it is being produced, or that it may be present within the cells in a precursor form not detectable by histochemical methods.

scholarly journals SYNCHRONIZATION OF MITOCHONDRIAL DNA SYNTHESIS IN CHINESE HAMSTER CELLS (LINE CHO) DEPRIVED OF ISOLEUCINE

1973 ◽  
Vol 58 (2) ◽  
pp. 340-345 ◽  
Author(s):  
Kenneth D. Ley ◽  
Marilyn M. Murphy
Keyword(s):  
Cell Cycle ◽  
Mitochondrial Dna ◽  
Dna Synthesis ◽  
Cell Cycle Progression ◽  
Time Course ◽  
Nuclear Dna ◽  
Tritiated Thymidine ◽  
Chinese Hamster ◽  
Chinese Hamster Cells ◽  
In Cells

Mitochondrial DNA (mit-DNA) synthesis was compared in suspension cultures of Chinese hamster cells (line CHO) whose cell cycle events had been synchronized by isoleucine deprivation or mitotic selection. At hourly intervals during cell cycle progression, synchronized cells were exposed to tritiated thymidine ([3H]TdR), homogenized, and nuclei and mitochondria isolated by differential centrifugation. Mit-DNA and nuclear DNA were isolated and incorporation of radioisotope measured as counts per minute ([3H]TdR) per microgram DNA. Mit-DNA synthesis in cells synchronized by mitotic selection began after 4 h and continued for approximately 9 h. This time-course pattern resembled that of nuclear DNA synthesis. In contrast, mit-DNA synthesis in cells synchronized by isoleucine deprivation did not begin until 9–12 h after addition of isoleucine and virtually all [3H]TdR was incorporated during a 3-h interval. We have concluded from these results that mit-DNA synthesis is inhibited in CHO cells which are arrested in G1 because of isoleucine deprivation and that addition of isoleucine stimulates synchronous synthesis of mit-DNA. We believe this method of synchronizing mit-DNA synthesis may be of value in studies of factors which regulate synthesis of mit-DNA.

Is Smooth Endoplasmic Reticulum Involved in Hepatic Glycogen Synthesis in the Fetal Mouse?

1985 ◽  
Vol 43 ◽  
pp. 496-497
Author(s):  
Joanette S. Breslin ◽  
Robert R. Cardell
Keyword(s):  
Endoplasmic Reticulum ◽  
Time Course ◽  
Smooth Endoplasmic Reticulum ◽  
Periodic Acid ◽  
Glycogen Synthesis ◽  
Microscopic Analysis ◽  
Hepatic Glycogen ◽  
Periodic Acid Schiff ◽  
Glycogen Deposition ◽  
Glycogen Particles

Considerable evidence suggests that hepatic smooth endoplasmic reticulum (SER) functions in both glycogen deposition and depletion and is closely associated with glycogen particles during both processes in the adult rodent liver. In this study we have investigated the time course of hepatic glycogen deposition and examined the association of SER with glycogen particles during fetal glycogen synthesis, i.e., from day 15 to day 19 of gestation (plug day = day 1).Livers were removed from fetal ICR mice and processed for either light (LM) and electron microscopy (EM) or biochemical determination of glycogen. Biochemical analysis of glycogen concentrations in each liver revealed an average of 0.1% glycogen in day 15 and day 16 fetal livers, 0.6% in those from day 17, 2.0% on day 18 and nearly 5.0% by day 19. Light microscopic analysis of periodic acid-Schiff (PAS) stained semi-thin (1.0μm) sections confirmed the presence of increasing amounts of glycogen beginning on day 16 and reaching a maximum on day 19 of gestation.

scholarly journals THE TIMING OF MEIOSIS AND DNA SYNTHESIS DURING EARLY OOGENESIS IN THE TOAD, XENOPUS LAEVIS

1972 ◽  
Vol 52 (3) ◽  
pp. 569-576 ◽  
Author(s):  
Lesley Watson Coggins ◽  
Joseph G. Gall
Keyword(s):  
Xenopus Laevis ◽  
Dna Synthesis ◽  
Time Course ◽  
Tritiated Thymidine ◽  
Extrachromosomal Dna ◽  
Cell Nuclei ◽  
Chromosomal Dna ◽  
Late Pachytene ◽  
Before And After ◽  
Major Period

Recently metamorphosed female Xenopus laevis toads were injected with tritiated thymidine. Animals were kept at 20°C and were sacrificed 1–23 days after isotope injection. Radio-autographs of squash preparations of the ovaries were made. The progress of labeled germ cell nuclei was followed to obtain information on the time course of early meiosis and extra-chromosomal DNA synthesis. Premeiotic S was estimated to take not more than 7 days. Leptotene takes 4 days, zygotene takes 5 days, and pachytene was estimated to be completed in about 18 days. The major period of amplification of the extrachromosomal DNA occurs in pachytene and takes about 13 days. A low level of synthesis was observed before and after this period, in zygotene and late pachytene-early diplotene, extending the total time for extrachromosomal DNA synthesis during meiosis to about 18 days. These data allowed the calculation to be made that one round of replication of the amplified DNA takes between 1.2 and 3.0 days. It was also found that in both oogonial and premeiotic interphases, the nucleolus-associated DNA shows asynchronous (probably late) labeling with respect to the chromosomes.

The seminiferous epithelial cycle and spermatogenesis in goats (Capra hircus)

1984 ◽  
Vol 103 (2) ◽  
pp. 359-368 ◽  
Author(s):  
G. S. Bilaspuri ◽  
S. S. Guraya
Keyword(s):  
Periodic Acid ◽  
Type A ◽  
Capra Hircus ◽  
Spermatogenic Cells ◽  
Type B ◽  
Periodic Acid Schiff ◽  
Three Generations ◽  
Two Generations ◽  
Spermatid Nucleus ◽  
Type Intermediate

SUMMARYThe development of the acrosomic system and the spermatid nucleus were used to define 14 stages of the seminiferous epithelial cycle in goats; these stages provided a basis for the examination of the behaviour of different spermatogenic cells which gave an idea of the efficiency of spermatogenesis. Eighteen steps of acrosome development (spermiogenesis) were observed in testicular material stained with periodic acid-Schiff. The first 14 steps were used to classify SEC into 14 (I–XIV) stages which in turn were employed to study the pattern of differentiation of spermatogenic cells by counting them in each stage of the cycle. Three generations of type A (A1, A2, A3), one generation of type intermediate (In) and two generations of type B (B1, B2) spermatogonia could be distinguished. A1 spermatogonia divided primarily in stages IX–X to produce A2 spermatogonia which in turn divided in stages XII–XIII to produce A3 spermatogonia and A, spermatogonia. A3 spermatogonia divided in stage XIV to produce In spermatogonia whereas A1 spermatogonia did not divide till the next cycle but underwent 26·3 % degeneration. In spermatogonia divided to form B1 spermatogonia in stages III–V which further divided to produce B2 spermatogonia in stage VI. Types A3, In and B2 spermatogonia showed 15·0, 25·0 and 25·8% degeneration respectively. B2 spermatogonia divided in stages VII–VIII to produce double the number of primary spermatocytes which persisted without any degeneration till stage XIII of the following cycle and divided at the beginning of stage XIV to form double the number of secondary spermatocytes. These cells divided at the end of stage XIV to form less than double the number of young round spermatids, showing 10·4% degeneration. It is concluded that the development of the acrosomic system as well as the spermatid nucleus could be conveniently used to study the behaviour of spermatogenic cells and that the process of spermatogenesis was less efficient than thought previously.

Ultrastructure of the Parotid Gland of the Nine-Banded Armadillo

1977 ◽  
Vol 35 ◽  
pp. 640-641
Author(s):  
J. R. Ruby
Keyword(s):  
Endoplasmic Reticulum ◽  
Parotid Gland ◽  
Periodic Acid ◽  
Acinar Cells ◽  
Duct System ◽  
Parotid Glands ◽  
Dasypus Novemcinctus ◽  
Anterior Portion ◽  
Periodic Acid Schiff ◽  
Thin Sections

Parotid glands were obtained from five adult (four male and one female) armadillos (Dasypus novemcinctus) which were perfusion-fixed. The glands were located in a position similar to that of most mammals. They extended interiorly to the anterior portion of the submandibular gland.In the light microscope, it was noted that the acini were relatively small and stained strongly positive with the periodic acid-Schiff (PAS) and alcian blue techniques, confirming the earlier results of Shackleford (1). Based on these qualities and other structural criteria, these cells have been classified as seromucous (2). The duct system was well developed. There were numerous intercalated ducts and intralobular striated ducts. The striated duct cells contained large amounts of PAS-positive substance.Thin sections revealed that the acinar cells were pyramidal in shape and contained a basally placed, slightly flattened nucleus (Fig. 1). The rough endoplasmic reticulum was also at the base of the cell.

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