Apoferritin in the vacuolar system of insect hemocytes

1991 ◽  
Vol 23 (3) ◽  
pp. 367-375 ◽  
Author(s):  
Michael Locke
Keyword(s):  
Insect Hemocytes ◽  
Vacuolar System

Structural aspects of osmoregulation in porphyra

1978 ◽  
Vol 36 (2) ◽  
pp. 412-413
Author(s):  
C. Wiencke ◽  
A. Lauchli
Keyword(s):  
Culture Medium ◽  
Point Of View ◽  
Chemical Fixation ◽  
Cellular Organization ◽  
Osmotic Adaptation ◽  
Osmotic Balance ◽  
Activity Of Enzymes ◽  
Osmotic Agents ◽  
Vacuolar System ◽  
Structural Aspects

Osmoregulatory mechanisms in algae were investigated mainly from a physiological point of view (KAUSS 1977, HELLEBUST 1976). In Porphyra two osmotic agents, i. e. floridoside/isofloridoside (KAUSS 1968) and certain ions, such as K+ and Na+(EPPLEY et al. 1960) are considered for osmotic balance. Accumulations of ions (particularly Na+) in the cytoplasm during osmotic adaptation is improbable, because the activity of enzymes is generally inhibited by high ionic concentrations (FLOWERS et al. 1977).The cellular organization of Porphyra was studied with special emphasis on the development of the vacuolar system under different hyperosmotic conditions. Porphyra was cultivated at various strengths of the culture medium ASP 12 (PROVASOLI 1961) ranging from normal to 6 times concentrated (6x) culture medium. Por electron microscopy freeze fracturing was used (specimens fixed in 2% glutaraldehyde and incubated in 30% glycerol, preparation in a BALZERS BA 360 M apparatus), because chemical fixation gave poor results.

The deposition of Hg203-chlormerodrin in experimental brain tumors

1971 ◽  
Vol 35 (3) ◽  
pp. 303-308 ◽  
Author(s):  
Tatsuya Kobayashi ◽  
Louis Bakay ◽  
Joseph C. Lee
Keyword(s):  
Brain Tumors ◽  
Tumor Cells ◽  
Normal Brain ◽  
Intracranial Tumors ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Content Type ◽  
Meningeal Tumors ◽  
Vacuolar System ◽  
Fine Print

✓ The deposition of Hg203-chlormerodrin was studied in intracranial tumors in mice induced by implantation of 20-methyl cholanthrene by tissue assay, as well as light microscopic and electron microscopic autoradiography. The investigations were carried out in astrocytomas, glioblastomas, and meningeal tumors. The chlormerodrin content of the tumors exceeded that of normal brain with a significant tumor/brain ratio ranging from 5.8 to 22.5. It was found that the chlormerodrin molecule becomes rapidly incorporated in the tumor cells, with a preference for that portion of the cytoplasm associated with the vacuolar system.

scholarly journals Tradescantia bracteata pollen in vitro: pollen tubes development and mitosis

2015 ◽  
Vol 46 (4) ◽  
pp. 587-598 ◽  
Author(s):  
E. Lewandowska ◽  
M. Charzyńska
Keyword(s):  
Pollen Tube ◽  
Generative Cell ◽  
Metaphase Plate ◽  
Pollen Grains ◽  
Neutral Red ◽  
Generative Nucleus ◽  
Mitotic Spindles ◽  
Germinating Pollen ◽  
Vacuolar System

About 90 per cent of <i>Tradescantia bracteata</i> pollen germinates <i>in vitro</i> after 15 min. Mitosis starts in the pollen tube after about 3 h. The mitotic trans-formations of chromosomes within the generative nucleus are not synchronized. They involve succesively the linearly arranged chromosomes in the elongated generative nucleus. In metaphase the chromosomes are arranged tandem-like linearly along the pollen tube. The chromatides translocate in anaphase from various distances to the poles in a plane parallel to the metaphase plate. This suggests that chromosomes have individual mitotic spindles and that coordination of the chromosome transformations in the generative cell is much less strict than in a typical somatic mitosis. Starch is the storage material of pollen grains. In the vegetative cytoplasm of mature pollen grains minute reddish-orange vesicular structures are visible after staining with neutral red. They do not fuse with the vacuoles proper arising in germinating pollen grains to form the vacuolar system of the pollen tube.

Internalisation of fluorescein isothiocyanate and fluorescein isothiocyanatedextran by suspension-cultured plant cells

1990 ◽  
Vol 96 (4) ◽  
pp. 721-730
Author(s):  
LOUISE COLE ◽  
JULLIAN COLEMAN ◽  
DAVID EVANS ◽  
CHRIS HAWES
Keyword(s):  
Fluorescence Microscopy ◽  
Incubation Period ◽  
Degradation Products ◽  
Plant Cells ◽  
Fluorescein Isothiocyanate ◽  
Kinetic Studies ◽  
Apparent Difference ◽  
Carrot Cells ◽  
Intracellular Compartments ◽  
Vacuolar System

The uptake of pure non-conjugated fluorescein isothiocyanate (FITC) and of the membraneimpermeant probe FITC—dextran into suspensioncultured carrot cells and protoplasts has been investigated. Commercial samples of a 70K (K=103Mr) FITC—dextran were shown to contain contaminant FITC and/or its degradation products, which were rapidly internalised into the vacuolar system of both cells and protoplasts. However, purified samples of the 70K FITC—dextran were taken up into the vacuoles of cells but not protoplasts after a lh incubation period. This apparent difference in the ability of cells and protoplasts to internalise FITC—dextrans was confirmed using samples of both commercial and purified 20K FITC—dextran as putative endocytotic probes. Both confocal and conventional fluorescence microscopy of FITC—treated cells have shown that FITC was internalised into similar intracellular compartments as was observed in cells treated with three-times purified 70K FITC—dextran. Thus, FITC was a useful fluorophore for rapidly labelling both the putative endocytotic compartments and the pleiomorphic vacuolar system of carrot cells. Kinetic studies indicated that FITC entered the cell by diffusion in the form of the neutral molecule. We have shown that treatment of cells or protoplasts with the drug Probenecid reversibly inhibited the uptake of FITC from the cytoplasm into the vacuole. In addition, the uptake of FITC into isolated vacuoles was enhanced in the presence of Mg-ATP

Effects of streptozotocin-induced diabetes on rough endoplasmic reticulum and lysosomes of rat liver

1992 ◽  
Vol 263 (5) ◽  
pp. E856-E862
Author(s):  
S. E. Lenk ◽  
D. Bhat ◽  
W. Blakeney ◽  
W. A. Dunn
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Serum Proteins ◽  
Serum Insulin ◽  
Normal Serum ◽  
Lysosomal Hydrolases ◽  
Insulin Dependent ◽  
Streptozotocin Induced Diabetes ◽  
Endogenous Proteins ◽  
Vacuolar System

In the absence of amino acids and insulin, ribosome-free regions of the rough endoplasmic reticulum (RER) invaginate to form an autophagosome, which matures into an autolysosome (W. A. Dunn, Jr., J. Cell Biol. 110: 1923-1933, 1990). In this study, biochemical and morphological methods were used to examine the structure and integrity of the RER and the lysosome-vacuolar system in livers of untreated (normal serum insulin) and streptozotocin (STZ)-treated (depressed serum insulin) fed and fasted rats. Degradation of endogenous proteins was increased by 70% in STZ-treated animals. Proteolysis was further enhanced when these animals were deprived of food for 24 h. These alterations in protein turnover were accompanied by increases in the fractional volume of autophagic vacuoles and in the hepatic amounts of three lysosomal hydrolases. These effects of STZ were prevented on administration of insulin. In addition, there was an insulin-dependent 50% loss of RER surface area in livers from STZ-treated rats. This loss of structural RER was accompanied by comparable decreases in the cellular amounts of two RER membrane proteins and one luminal protein, suggesting that the RER was degraded as a unit. Additional losses of RER were observed when STZ-treated rats were fasted. Furthermore, the hepatic amounts of two serum proteins decreased, suggesting the functional capacity of the RER was reduced. Combined, the data suggest that in STZ-induced diabetes the losses in RER are related to enhanced autophagy.

Ultrastructural analysis of VIP internalization in rat beta- and acinar cells in situ

1989 ◽  
Vol 256 (4) ◽  
pp. G689-G697
Author(s):  
A. Anteunis ◽  
A. Astesano ◽  
B. Portha ◽  
G. Hejblum ◽  
G. Rosselin
Keyword(s):  
High Resolution ◽  
Cell Surface ◽  
Beta Cells ◽  
Specific Activity ◽  
Acinar Cells ◽  
Volume Density ◽  
Computer Assisted ◽  
Assisted Analysis ◽  
Vacuolar System

We perfused the pancreas with 125I-labeled vasoactive intestinal peptide (VIP) to follow the concomitant distribution of radioactivity in beta- and acinar cells as a function of time. This distribution was quantitated by computer-assisted analysis of high-resolution video autoradiographs. Density labeling was expressed as normalized specific activity (disintegration density per volume density). Immediately after a 4-min perfusion of 125I-VIP, labeling in beta-cells was mainly concentrated on the cell surface and peripheral tubules and vesicles. After three 30-s pulses of 125I-VIP, separated by intervals of 3.5 min of buffer perfusion, lysosome-like structures were heavily labeled. When VIP internalization was prolonged, labeling was similar to that observed with the 4-min perfusion, indicating a high VIP disposal rate in the lysosome-like structures. In acinar cells, labeling persisted on the surface and the early vacuolar system. We conclude the following: 1) an active endocytotic system, linked to the transport and sorting of a neuromediator, is present in beta-cells; and 2) the differences between the distribution of labeling in acinar and beta-cells suggest that the regulation of VIP internalization is tissue specific.

scholarly journals THE EFFECT OF POLY-L-LYSINE ON THE UPTAKE OF REOVIRUS DOUBLE-STRANDED RNA IN MACROPHAGES IN VITRO

1973 ◽  
Vol 57 (2) ◽  
pp. 484-498 ◽  
Author(s):  
Rolf Seljelid ◽  
Samuel C. Silverstein ◽  
Zanvil A. Cohn
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Surface ◽  
Nucleic Acids ◽  
Acid Hydrolases ◽  
Cell Compartment ◽  
Double Stranded Rna ◽  
Secondary Lysosomes ◽  
Toxic Concentrations ◽  
Vacuolar System

The effect of polycations on cultured mouse peitoneal macrophages has been examined. Polycations, at concentrations greater than 5 µg/ml, are toxic for macrophages) as measured by failure of the cells to exclude vital dyes. At toxic concentrations polycations bind in large amounts to nuclei and endoplasmic reticulum, while at nontoxic levels polycations bind selectively to the cell surface. Nontoxic concentrations of polycations stimulate binding of reovirus double-stranded (ds) RNA to the macrophages by forming polycation-dsRNA complexes either in the medium or at the cell surface. These complexes enter the cell in endocytic vacuoles and are concentrated in secondary lysosomes. Despite exposure to the acid hydrolases within this cell compartment, the dsRNA and the polycation (poly-L-lysine) are conserved in a macromolecular form within the vacuolar system. The mechanism(s) by which the uptake of infectious nucleic acids and the induction of interferon by dsRNA are stimulated by polycations are discussed.

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