scholarly journals Characterization of early compartments in fluid phase pinocytosis: a cell fractionation study

1986 ◽  
Vol 83 (1) ◽  
pp. 119-133
Author(s):  
K.A. Casey ◽  
K.M. Maurey ◽  
B. Storrie
Keyword(s):  
Cell Surface ◽  
Early Stage ◽  
Chinese Hamster ◽  
Fluid Phase ◽  
Cell Fractionation ◽  
Median Diameter ◽  
A Cell ◽  
Two Populations ◽  
Pinocytic Vesicles

Flotation through a 5.6% Percoll gradient of pinosomes from Chinese hamster ovary (CHO) cells labelled during a 10 min internalization period with horseradish peroxidase (HRP), a solute, revealed two pinosomal populations, the expected low-buoyancy population and an unexpected buoyant population. The buoyant pinosomes that sedimented similarly to plasma membrane were not an artifact of HRP trapping during homogenization or of cell surface-adherent HRP. No trapping or cell surface adherence of HRP could be detected by biochemical or cytochemical assays, even after internalization periods as short as 15 s to 1 min. With short uptake times, the buoyant pinosome population was the major HRP positive vesicle population, suggesting a precursor-to-product relationship between the two populations. In pulse-chase experiments, the buoyant pinosome population was shown to be highly exocytic and the precursor to later pinosomes. By electron-microscope cytochemistry, rapidly labelled, HRP positive pinosomes (15 s to 1 min uptake) were typically smooth vesicles with a median diameter of approximately equal to 0.30 micron and a size range from approximately equal to 0.10 micron to greater than 1.0 micron in diameter. We suggest that these rapidly labelled structures are a very early stage in the intracellular processing of pinocytic vesicles.

Characterization of fucosyltransferase activity during mouse spermatogenesis: evidence for a cell surface fucosyltransferase

Biochemistry ◽  
1989 ◽  
Vol 28 (4) ◽  
pp. 1611-1617 ◽  
Author(s):  
Richard A. Cardullo ◽  
D. Randall Armant ◽  
Clarke F. Millette
Keyword(s):  
Cell Surface ◽  
A Cell

scholarly journals Characterization of a cell cycle mutant derived from hamster fibroblast: reversion analysis.

1982 ◽  
Vol 92 (3) ◽  
pp. 629-633 ◽  
Author(s):  
D J Scharff ◽  
A M Delegeane ◽  
A S Lee
Keyword(s):  
Cell Line ◽  
Mutant Cell ◽  
Chinese Hamster ◽  
Temperature Sensitive ◽  
Nonpermissive Temperature ◽  
Molecular Weights ◽  
A Cell ◽  
Ts Mutant ◽  
Spontaneous Revertant

K12 is a temperature-sensitive (ts) mutant cell line derived from Chinese hamster fibroblasts. When incubated at the nonpermissive temperature, K12 cells exhibit the following properties: (a) the cells cannot initiate DNA synthesis;o (b) the synthesis of cytosol thymidine kinase is suppressed; and (c) the synthesis of three cellular proteins of molecular weights 94, 78, and 58 kdaltons is greatly enhanced. Here we characterize a spontaneous revertant clone, R12, derived from the K12 cells. We selected the revertant clone for its ability to grow at the nonpermissive temperature. Our results indicate that all the traits which constitute the K12 mutant phenotype are simultaneously reverted to the wild type in the revertant cell line, suggesting that the ts mutation of the K12 cells is of regulatory nature and exerts multiple effects on the expressed phenotypes.

Biochemical Characterization of the Histidine Triad Protein PhtD as a Cell Surface Zinc-Binding Protein of Pneumococcus

Biochemistry ◽  
2011 ◽  
Vol 50 (17) ◽  
pp. 3551-3558 ◽  
Author(s):  
Elodie Loisel ◽  
Suneeta Chimalapati ◽  
Catherine Bougault ◽  
Anne Imberty ◽  
Benoit Gallet ◽  
...  
Keyword(s):  
Cell Surface ◽  
Biochemical Characterization ◽  
Binding Protein ◽  
Zinc Binding ◽  
A Cell

scholarly journals Isolation and characterization of Chinese hamster ovary cell variants defective in adhesion to fibronectin-coated collagen.

1980 ◽  
Vol 87 (3) ◽  
pp. 755-763 ◽  
Author(s):  
P A Harper ◽  
R L Juliano
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Divalent Cations ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Human Diploid Fibroblasts ◽  
Isolation And Characterization ◽  
A Cell ◽  
Cold Insoluble Globulin

Variant clones of Chinese hamster ovary (CHO) cells were selected for reduced adhesion to serum-coated tissue culture plates. These clones also displayed reduced adhesion to substrata composed of collagen layers coated with bovine serum or with fibronectin (cold-insoluble globulin). Wild-type (WT) and adhesion variant (ADv) cells grew at comparable rates in suspension culture, but the adhesion variants could not be grown in monolayer culture because of their inability to attach to the substratum. The adhesion deficit in these cells was not corrected by raising the concentration of divalent cations or of serum to levels 10-fold greater than those normally utilized in cell culture. However, both WT and ADv clones could adhere, spread, and attain a normal CHO morphology on substrata coated with concanavalin A or poly-L-lysine. In addition, the adhesion variants could attach to substrata coated with "footpad" material (substratum-attached material) derived from monolayers of human diploid fibroblasts or WT CHO cells. These observations suggest that the variant clones may have a cell surface defect that prevents them from utilizing exogeneous fibronectin as an adhesion-promoting ligand; however the variants seem to have normal cytoskeletal and metabolic capacities that allow them to attach and spread on substrata coated with alternative ligands. These variants should be extremely useful in studying the molecular basis of cell adhesion.

scholarly journals Chinese hamster ovary cell lysosomes retain pinocytized horseradish peroxidase and in situ-radioiodinated proteins.

1984 ◽  
Vol 4 (2) ◽  
pp. 296-301 ◽  
Author(s):  
B Storrie ◽  
M Sachdeva ◽  
V S Viers
Keyword(s):  
Horseradish Peroxidase ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Fluid Phase ◽  
Ovary Cell ◽  
Cell Fractionation ◽  
Marker Enzyme ◽  
Ovary Cells

We used Chinese hamster ovary cells, a cell line of fibroblastic origin, to investigate whether lysosomes are an exocytic compartment. To label lysosomal contents, Chinese hamster ovary cells were incubated with the solute marker horseradish peroxidase. After an 18-h uptake period, horseradish peroxidase was found in lysosomes by cell fractionation in Percoll gradients and by electron microscope cytochemistry. Over a 24-h period, lysosomal horseradish peroxidase was quantitatively retained by Chinese hamster ovary cells and inactivated with a t 1/2 of 6 to 8 h. Lysosomes were radioiodinated in situ by soluble lactoperoxidase internalized over an 18-h uptake period. About 70% of the radioiodine incorporation was pelleted at 100,000 X g under conditions in which greater than 80% of the lysosomal marker enzyme beta-hexosaminidase was released into the supernatant. By one-dimensional electrophoresis, about 18 protein species were present in the lysosomal membrane fraction, with radioiodine incorporation being most pronounced into species of 70,000 to 75,000 daltons. After a 30-min or 2-h chase at 37 degrees C, radioiodine that was incorporated into lysosomal membranes and contents was retained in lysosomes. These observations indicate that lysosomes labeled by fluid-phase pinocytosis are a terminal component of endocytic pathways in fibroblasts.

scholarly journals Characterization of a Cell-surface Protein Antigen of Hydrophilic Streptococcus mutans Strain GS-5

Microbiology ◽  
1989 ◽  
Vol 135 (4) ◽  
pp. 981-988 ◽  
Author(s):  
H. Ohta ◽  
H. Kato ◽  
N. Okahashi ◽  
I. Takahashi ◽  
S. Hamada ◽  
...  
Keyword(s):  
Cell Surface ◽  
Streptococcus Mutans ◽  
Surface Protein ◽  
Protein Antigen ◽  
Cell Surface Protein ◽  
A Cell

scholarly journals Genetic Characterization of a Cell Envelope-Associated Proteinase from Lactobacillus helveticus CNRZ32

1999 ◽  
Vol 181 (15) ◽  
pp. 4592-4597 ◽  
Author(s):  
Jeffrey A. Pederson ◽  
Gerald J. Mileski ◽  
Bart C. Weimer ◽  
James L. Steele
Keyword(s):  
Cell Surface ◽  
Deletion Mutant ◽  
Cell Envelope ◽  
Physiological Role ◽  
Lactobacillus Helveticus ◽  
Whole Cells ◽  
A Cell ◽  
Hydrolysis Of

ABSTRACT A cell envelope-associated proteinase gene (prtH) was identified in Lactobacillus helveticus CNRZ32. TheprtH gene encodes a protein of 1,849 amino acids and with a predicted molecular mass of 204 kDa. The deduced amino acid sequence of the prtH product has significant identity (45%) to that of the lactococcal PrtP proteinases. Southern blot analysis indicates thatprtH is not broadly distributed within L. helveticus. A prtH deletion mutant of CNRZ32 was constructed to evaluate the physiological role of PrtH. PrtH is not required for rapid growth or fast acid production in milk by CNRZ32. Cell surface proteinase activity and specificity were determined by hydrolysis of αs1-casein fragment 1-23 by whole cells. A comparison of CNRZ32 and its prtH deletion mutant indicates that CNRZ32 has at least two cell surface proteinases that differ in substrate specificity.

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