A sponge/dinoflagellate association in the haplosclerid sponge Haliclona sp.: cellular origin of cytotoxic alkaloids by Percoll density gradient fractionation

1998 ◽  
Vol 293 (2) ◽  
pp. 365-373 ◽  
Author(s):  
M. J. Garson ◽  
Andrew E. Flowers ◽  
Richard I. Webb ◽  
Romila D. Charan ◽  
Elizabeth J. McCaffrey
Keyword(s):  
Density Gradient ◽  
Cellular Origin ◽  
Percoll Density Gradient ◽  
Gradient Fractionation ◽  
Percoll Density Gradient Fractionation

scholarly journals Intracellular routing of GLcNAc-bearing molecules in thyrocytes: selective recycling through the Golgi apparatus.

1993 ◽  
Vol 123 (6) ◽  
pp. 1695-1706 ◽  
Author(s):  
R Miquelis ◽  
J Courageot ◽  
A Jacq ◽  
O Blanck ◽  
C Perrin ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Fluid Phase ◽  
Intake Rate ◽  
Cell Fractionation ◽  
Extracellular Milieu ◽  
Cell Homogenate ◽  
Discontinuous Sucrose Gradient ◽  
Percoll Density Gradient ◽  
Gradient Fractionation ◽  
Percoll Density Gradient Fractionation

Previous experiments led us to speculate that thyrocytes contain a recycling system for GlcNAc-bearing immature thyroglobulin molecules which prevents these molecules from lysosomal degradation (Miquelis, R., C. Alquier, and M. Monsigny. 1987. J. Biol. Chem. 262:15291-15298). To confirm this hypothesis, the fate of GlcNAc-bearing proteins after internalization by thyrocytes was monitored and compared to that of fluid phase markers. Kinetic internalization studies were performed using 125I-GlcNAc-BSA and 131I-Man-BSA. We observed that the apparent intake rate as well as the amount of hydrolyzed GlcNAc-BSA are smaller than the corresponding values for Man-BSA. These differences were reduced by GlcNAc competitors (thyroglobulin and ovomucoid) or a weak base (chloroquine). Part of the internalized GlcNAc-BSA was released into the extracellular milieu at a higher rate and shorter half life (t1/2 = approximately 30 min) than the Man-BSA (t1/2 = approximately 8 h). Subcellular homing was first studied by cell fractionation after internalization using 125I-ovomucoid and 131I-BSA. During Percoll density gradient fractionation, endogenous thyroperoxidase was used to separate subsets of organelles involved in the biosynthetic exocytotic pathway. Incubation of the cell homogenate in the presence of DAB and H2O2 before cell fractionation give rise to a shift in the density of organelles containing 3.5 times more ovomucoid than BSA. Discontinuous sucrose gradient showed that: (a) thyroperoxidase was colocalized with galactosyltransferase-contraining organelles in Golgi-rich subfractions; and (b) that at every time studied from 10 to 100 min, the ovomucoid/BSA ratio was higher in these organelles than in other subfractions. Finally we also observed that: (a) ovomucoid sequestered in the Golgi-rich subfraction incorporated [3H]galactose; and (b) that part of internalized ovomucoid was localized on the Golgi stacks as well as elements of the trans-Golgi, as revealed by immunogold labeling on ultrathin cryosections. These data prove that in thyrocytes GlcNAc accessible sugar moieties on soluble internalized molecules are sufficient to trigger their recycling via the Golgi apparatus.

scholarly journals Purification and production of Plasmodium falciparum zygotes from in vitro culture using magnetic column and Percoll density gradient

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Yaxian Zhou ◽  
Alexis M. Grieser ◽  
Julie Do ◽  
Leslie S. Itsara ◽  
Ashley M. Vaughan ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
In Vitro Culture ◽  
Density Gradient ◽  
Percoll Density Gradient

Isolation of oligodendroglial cells from young and adult whole rat brains using an in situ generated percoll density gradient

1984 ◽  
Vol 6 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Liliana N. Berti Mattera ◽  
Jorge N. Larocca ◽  
Amanda Pellegrino de Iraldi ◽  
Juana M. Pasquini ◽  
Eduardo F. Soto
Keyword(s):  
Density Gradient ◽  
Percoll Density Gradient

Human erythrocyte separation according to age on a discontinuous ‘Percoll’ density gradient

1982 ◽  
Vol 122 (2) ◽  
pp. 293-300 ◽  
Author(s):  
Giuseppe Salvo ◽  
Patrizia Caprari ◽  
Paola Samoggia ◽  
Gualtiero Mariani ◽  
Anna Maria Salvati
Keyword(s):  
Density Gradient ◽  
Human Erythrocyte ◽  
Percoll Density Gradient ◽  
Discontinuous Percoll Density Gradient

Purification of dispersed rat adrenal zona glomerulosa cells by Percoll density gradient centrifugation and the isolation of a population of cells highly responsive to adrenocorticotrophin

1986 ◽  
Vol 109 (3) ◽  
pp. 351-NP ◽  
Author(s):  
F. W. Chu ◽  
P. J. Hyatt
Keyword(s):  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Sephadex Column ◽  
Percoll Density Gradient Centrifugation ◽  
Percoll Density Gradient ◽  
Glomerulosa Cells ◽  
Unit Gravity Sedimentation

ABSTRACT Percoll density gradient centrifugation is a simple, inexpensive and convenient method to eliminate contaminating zona fasciculata (ZF) cells from unpurified rat adrenal capsular glomerulosa (ZG) cell preparations (with less than 0·1% ZF cells in the final cell preparation). Basal steroid (aldosterone and corticosterone) output by the purified (PG) cells was unchanged. These purified cells, although free from ZF contamination, were more highly responsive than expected to ACTH (3 nmol/l). When PG cells were further separated by Sephadex column filtration, the filtered PG cells exhibited the steroidogenic response of ZG cells purified by unit gravity sedimentation and Sephadex column filtration, i.e. reduced basal steroid output and an ACTH response reduced to that stimulated by K+ (8·4 mmol/l). Although the cells retained in the column resembled the filtered PG cells ultrastructurally, they showed unchanged basal steroid output and a high ACTH response with increased latepathway activity (the conversion of corticosterone to aldosterone). By combining Percoll density gradient centrifugation and Sephadex column filtration we have a method for the isolation and study of both the high-and low-response rat ZG cells which are free from ZF contamination. J. Endocr. (1986) 109, 351–358

scholarly journals Subpopulations of rat hepatocytes separated by Percoll density-gradient centrifugation show characteristics consistent with different acinar locations

1994 ◽  
Vol 304 (2) ◽  
pp. 617-624 ◽  
Author(s):  
J C Osypiw ◽  
R L Allen ◽  
D Billington
Keyword(s):  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Rat Hepatocytes ◽  
Marker Enzymes ◽  
Cytotoxic Effects ◽  
Percoll Density Gradient Centrifugation ◽  
Cell Layers ◽  
Density Band ◽  
Percoll Density Gradient

Freshly isolated viable rat hepatocytes were separated into five subpopulations on shallow discontinuous Percoll density gradients. The periportal marker enzymes alanine aminotransferase (ALT), malate dehydrogenase (MDH) and lactate dehydrogenase (LDH) showed gradients of increasing activity from the subpopulation of least density (band 1, rho = 1.07 g/ml) to the subpopulation of greatest density (band 5, rho = 1.09 g/ml). The perivenous marker enzymes pyruvate kinase (PK) and glutamate dehydrogenase (GDH) showed gradients of decreasing activity from band-1 cells to band-5 cells. Glutamine synthetase (GS), which is confined to the two or three cell layers around the hepatic venule, was almost entirely restricted to band-1 hepatocytes. Band-5: band-1 ratios of enzyme activity were as follows: ALT, 8.0; LDH, 2.1; MDH, 1.6; GDH, 0.7; PK, 0.2; GS, 0.01. Band-5:band-1 ratios for ALT, LDH, PK and GS were maintained after culture of subpopulations in identical conditions for up to 72 h, whereas the ratios for MDH and GDH decreased and increased respectively towards unity. Band-1 hepatocytes exhibited greater cytotoxicity than band-5 cells after incubation with carbon tetrachloride or paracetamol. These perivenous-selective toxins produced greater decreases in cell viability and greater release of ALT and LDH from band-1 hepatocytes than from band-5 hepatocytes. Conversely, band-5 hepatocytes were more susceptible than band-1 hepatocytes to the cytotoxic effects of 1-naphthylisothiocyanate and methotrexate (known periportal-selective toxins). It is concluded that band-5 hepatocytes are enriched in periportal cells, whereas band-1 hepatocytes are enriched in perivenous cells. Isolation of hepatocyte subpopulations by Percoll density-gradient centrifugation has the considerable advantage that periportal and perivenous cells can be obtained from the same liver.

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