scholarly journals Effects of morphology on phonons in nanoscopic silver grains

2005 ◽  
Vol 72 (15) ◽  
Author(s):  
Gustavo A. Narvaez ◽  
Jeongnim Kim ◽  
John W. Wilkins
Keyword(s):  
Silver Grains

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.

scholarly journals SYNTHESIS AND MIGRATION OF PROTEINS IN THE CELLS OF THE EXOCRINE PANCREAS AS REVEALED BY SPECIFIC ACTIVITY DETERMINATION FROM RADIOAUTOGRAPHS

1963 ◽  
Vol 16 (1) ◽  
pp. 1-23 ◽  
Author(s):  
H. Warshawsky ◽  
C. P. Leblond ◽  
B. Droz
Keyword(s):  
Specific Activity ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Zymogen Granule ◽  
Zymogen Granules ◽  
The Mean ◽  
And Migration ◽  
Rats And Mice ◽  
Silver Grains ◽  
Golgi Zone

Radioautographs of pancreatic acinar cells were prepared in rats and mice sacrificed at various times after injection of leucine-, glycine-, or methionine-H3. Measurements of radioactivity concentration (number of silver grains per unit area) and relative protein concentration (by microspectrophotometry of Millon-treated sections) yielded the mean specific activity of proteins in various regions of the acinar cells. The 2 to 5 minute radioautographs as well as the specific activity time curves demonstrate protein synthesis in ergastoplasm. From there, most newly synthesized proteins migrate to and accumulate in the Golgi zone. Then they spread to the whole zymogen region and, finally, enter the excretory ducts. An attempt at estimating turnover times indicated that two classes of proteins are synthesized in the ergastoplasm: "sedentary" with a slow turnover (62.5 hours) and "exportable" with rapid turnover (4.7 minutes). It is estimated that the exportable proteins spend approximately 11.7 minutes in the Golgi zone where they are built up into zymogen granules, and thereafter 36.0 minutes as fully formed zymogen granules, before they are released outside the acinar cell as pancreatic secretion. The mean life span of a zymogen granule in the cell is estimated to be 47.7 minutes.

scholarly journals BioFilm©

2000 ◽  
Vol 8 (2) ◽  
pp. 6-7
Author(s):  
Lee van Hook
Keyword(s):  
Recent Article ◽  
Metal Halide ◽  
Toxic Effects ◽  
Polymer Science ◽  
Complex Combination ◽  
Dry Biomass ◽  
Equilateral Triangles ◽  
Silver Grains

Photographic chemistry has long been a complex combination of inorganic metal-halide and organic chemistries and polymer science. We at the P.R.I, have managed to add biology to this stew.Silver has long been known as a toxicelement to microbes, and so used as a drug to kill bacteria. But there are bacteria that can survive in environments high in silver. It has been reported that some bacteria can accumulate up to 25% of their dry biomass as silver, and so acquire resistance to the toxic effects of silver. Also, a recent article in the Proc. Nat. Acad.Sci. describes the intracellular deposition of silver grains in such shapes as hexagons and equilateral triangles.

Synthesis of nuclear and cytoplasmic proteins in the early development of fishes and echinoderms

Development ◽  
1971 ◽  
Vol 26 (3) ◽  
pp. 611-622
Author(s):  
Maya R. Krigsgaber ◽  
Alla A. Kostomarova ◽  
Tamara A. Terekhova ◽  
Tatiana A. Burakova
Keyword(s):  
Amino Acids ◽  
Early Development ◽  
Sea Urchin ◽  
Nuclear Volume ◽  
Sea Urchin Embryos ◽  
Cytoplasmic Proteins ◽  
Specific Activities ◽  
Strongylocentrotus Nudus ◽  
Silver Grains ◽  
Misgurnus Fossilis

Synthesis of nuclear and cytoplasmic proteins was studied biochemically and autoradiographically in early loach (Misgurnus fossilis) and sea-urchin (Strongylocentrotus nudus) embryos. After incubation with [14C]amino acids for 5–120 min the ratio of the specific activities of nuclear, mitochondrial and 12000 g supernatant proteins was shown to be equal approximately to 6:1:2 in loach embryos and to 8:4:3 in sea-urchin embryos independently of the duration of labelling. After incubation with [3H]amino acids the number of silver grains per unit section was on the average 2·4 times higher for nuclei than it was for cytoplasm at mid-blastula and mid-gastrula stages. At the mid-gastrula the vegeto-animal gradient of protein synthesis was found. A higher level of the synthesis of nuclear proteins as compared with that of cytoplasmic proteins appears to be related to an increase in the nuclear volume and the nucleo-cytoplasmic ratio during the early development of the loach and sea-urchin embryos.

The Synthesis and Migration of Nuclear Proteins during Mitosis and differentiation of Cells in Rats

1965 ◽  
Vol s3-106 (75) ◽  
pp. 229-240
Author(s):  
R. T. SIMS
Keyword(s):  
Granular Cell ◽  
Nuclear Proteins ◽  
Photographic Emulsion ◽  
Metaphase Chromosomes ◽  
Interphase Nuclei ◽  
Cell Layers ◽  
The Difference ◽  
Mitotic Figures ◽  
And Migration ◽  
Silver Grains

Hooded rats were given an intraperitoneal injection of 3H-tyrosine, and killed in pairs 10 min, 30 min, 12 h, 36 h, 7 days, and 30 days later. A piece of skin with white growing hair, and the tongue, were taken from each animal and radioautographs were prepared. Silver grains were counted over whole nuclei and whole mitotic figures of the germinal cells and whole nuclei of differentiating cells of both tissues. It was found that the interphase nuclei have significantly more silver grains over them than the chromosomes at all stages of mitosis and there are virtually no grains over metaphase, anaphase, and early telophase chromosomes in both tissues of all the animals killed up to 36 h after the injection. The difference between the grain counts over the interphase nuclei and the chromosomes of dividing cells is at least 20-fold at 30 min in the hair matrix, at least 5-fold at 30 min in the tongue and at 36 h in both tissues. It was established that the differences observed between the radioactivities of the nuclei and chromosomes of mitotic figures are real from estimates of: the radioactivity of the cell cytoplasm, volumes of the metaphase chromosomes and interphase nuclei within 1µ of the photographic emulsion, and the volumes of cytoplasm separating the photographic emulsion and these structures. No protein synthesis was demonstrable in the chromosomes during metaphase, anaphase, and early telophase. Nuclear proteins leave the chromosomes during prophase and prometaphase and return to the nucleus during late telophase. The cells in the matrix and upper bulb of the growing hair follicle and those in the germinal, prickle, and granular cell layers of the tongue are in different functional states; 30 min after injection of 3H-tyrosine they have different amounts of it in their nuclear proteins. It is suggested that the amount incorporated into each nucleus is related to the rate at which proteins are being synthesized by the cell.

scholarly journals AUTORADIOGRAPHIC LOCALIZATION OF NEW RNA SYNTHESIS IN HYPERTROPHYING SKELETAL MUSCLE

1973 ◽  
Vol 57 (3) ◽  
pp. 743-759 ◽  
Author(s):  
Charles K. Jablecki ◽  
John E. Heuser ◽  
Seymour Kaufman
Keyword(s):  
Skeletal Muscle ◽  
Connective Tissue ◽  
Rna Synthesis ◽  
Proliferating Cells ◽  
Quantitative Studies ◽  
Physiological Adaptations ◽  
Rat Soleus Muscle ◽  
Tissue Cells ◽  
A Site ◽  
Silver Grains

Work-induced growth of rat soleus muscle is accompanied by an early increase in new RNA synthesis. To determine the cell type(s) responsible for the increased RNA synthesis, we compared light autoradiographs of control and hypertrophying muscles from rats injected with tritiated uridine 12, 24, and 48 h after inducing hypertrophy. There was an increased number of silver grains over autoradiographs of hypertrophied muscle. This increase occurred over connective tissue cells; there was no increase in the number of silver grains over the muscle fibers. Quantitative studies demonstrated that between 70 and 80% of the radioactivity in the muscle that survived fixation and washing was in RNA. Pretreatment of the animals with actinomycin D reduced in parallel both the radioactivity in RNA and the number of silver grains over autoradiographs. Proliferation of the connective tissue in hypertrophying muscle was evident in light micrographs, and electron micrographs identified the proliferating cells as enlarged fibroblasts and macrophages; the connective tissue cells remained after hypertrophy was completed. Thus, proliferating connective tissue cells are the major site of the increase in new RNA synthesis during acute work-induced growth of skeletal muscle. It is suggested that in the analysis of physiological adaptations of muscle, the connective tissue cells deserve consideration as a site of significant molecular activity.

Evidence for hibbingite–kempite solid solution

1998 ◽  
Vol 62 (2) ◽  
pp. 251-255 ◽  
Author(s):  
Bernhardt Saini-Eidukat ◽  
Nikolai S. Rudashevsky ◽  
Alexander G. Polozov
Keyword(s):  
Solid Solution ◽  
Siberian Platform ◽  
Lower Paleozoic ◽  
Fine Grained ◽  
Platinum Group Minerals ◽  
Mineral Assemblages ◽  
Native Silver ◽  
Chalcopyrite Ore ◽  
Silver Grains ◽  
New Occurrences

AbstractNew occurrences of hibbingite, γ-Fe2(OH)3Cl, have been found associated with platinum-group minerals in the Noril'sk Complex, and with the Korshunovskoye iron ores of the southern Siberian platform. The Norils'k grains, which are up to 0. 6 mm in diameter, are associated with the platinumgroup minerals froodite, cabriite, urvantsevite and with native silver in massive pentlandite–cubanite– chalcopyrite ore. The Korshunovskoye iron ore sample in which hibbingite was found is composed of fine-grained magnetite ore associated with halite. Hibbingite, hematite and silver grains are found in cavities in halite; the reddish-brown hibbingite grains usually occur as encrustations in the cavities. The size of hibbingite and hematite grains is up to 100 µm.Hibbingite from the Noril'sk Complex contains a significant kempite (Mn2(OH)3Cl) component; in some cases it contains over 50 mol. % Mn. These data suggest that at least a partial solid solution series exists between hibbingite and kempite. All known occurrences of hibbingite represent paragenetically late mineral assemblages. In the case of the Korshunovskoye deposits, the occurrences are associated with highly concentrated hydrothermal brines derived from the Lower Paleozoic saline sediments of the Siberian Platform cover.

Pattern of Incorporation of [3H]Uridine into RNA of Amphibian Oocyte Nucleoli

1967 ◽  
Vol 2 (2) ◽  
pp. 145-150
Author(s):  
H. C. MACGREGOR
Keyword(s):  
Nuclear Envelope ◽  
Incubation Time ◽  
Core Material ◽  
Distinct Component ◽  
Thin Sections ◽  
The Core ◽  
Amphibian Oocyte ◽  
Nucleolar Rna ◽  
Silver Grains

Amphibian oocytes were incubated in vitro in the presence of [3H]uridine, and autoradiographs were made of nucleoli isolated from these oocytes and of sections of oocytes. After incubations of 2 h or less the nucleoli of oocytes larger than 0.6 mm diameter are asymmetrically labelled. With longer incubations nucleoli from oocytes of 0.6 to 1.1 mm diameter become more uniformly labelled. Those of oocytes larger than 1.2 mm diameter remain asymmetrically labelled whatever the incubation time. Autoradiographs of 1-µ sections through oocytes larger than 0.6 mm diameter show, after short incubations, asymmetrically labelled nucleoli. In these autoradiographs silver grains are concentrated over a distinct component of each nucleolus which is eccentrically placed towards the nuclear envelope. Thin sections of oocytes show nucleoli consisting of core and cortex. The core material is always concentrated into the half of the nucleolus which lies nearer the nuclear envelope. Autoradiographs of separated nucleolar cores and cortices from oocytes larger than 0.6 mm diameter show, after short incubations, silver grains over cores but not over cortices. Similar autoradiographs prepared from oocytes of 0.6 to 1.1 mm diameter, after longer incubations, show grains over cores and cortices. These results appear to indicate that nucleolar RNA is synthesized in the nucleolar core, in association with the nucleolar DNA, and is thence transferred to the cortex where it is built into ribonucleoprotein particles. Initial asymmetrical labelling is a consequence of the eccentric location of the nucleolar core. The nucleoli of oocytes smaller than 0.6 mm diameter always label symmetrically; such nucleoli consist entirely of core material. It is suggested that the nucleoli of oocytes larger than 1.2 mm diameter always label asymmetrically because transfer of RNA from core to cortex proceeds more slowly than in smaller oocytes.

scholarly journals MORPHOLOGICAL AND BIOCHEMICAL STUDIES OF B CELLS OF FETAL RAT ENDOCRINE PANCREAS IN ORGAN CULTURE

1971 ◽  
Vol 50 (3) ◽  
pp. 565-582 ◽  
Author(s):  
Lelio Orci ◽  
Andre E. Lambert ◽  
Yasunori Kanazawa ◽  
Mylene Amherdt ◽  
Charles Rouiller ◽  
...  
Keyword(s):  
B Cells ◽  
Organ Culture ◽  
Endocrine Pancreas ◽  
De Novo ◽  
Immunoreactive Insulin ◽  
De Novo Synthesis ◽  
Complex Activity ◽  
Golgi Region ◽  
Fetal Rat ◽  
Silver Grains

Fetal rat pancreases explanted on the 18th day of gestation and maintained in organ culture for 1–10 days were utilized for this series of studies. Ultrastructurally, at the time of explantation, the majority of fetal B cells was sparsely granulated and characterized by numerous free ribosomes and undeveloped rough endoplasmic reticulum (RER) and Golgi complexes. During the culture period, extensive development of the RER and Golgi complexes preceded an increasing accumulation of ß-granules. This later increase in the number of ß-granules and in the concentration of immunoreactive insulin was paralleled by a reduction of RER and Golgi complex activity. High resolution radioautographic studies of pulse-chase experiment over a 1 hr period demonstrated the shift of silver grains from the elements of the RER, through the Golgi region, and finally to the ß-granules. Incubation with 14C-labeled leucine demonstrated the incorporation of radioactivity into molecules possessing the immunological and electrophoretic properties of insulin. These studies indicate that de novo synthesis of (pro)insulin occurs also during culture of fetal rat pancreas explanted relatively late in gestation.

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