scholarly journals Routing of internalized ricin and ricin conjugates to the Golgi complex.

1986 ◽  
Vol 102 (1) ◽  
pp. 37-47 ◽  
Author(s):  
B van Deurs ◽  
T I Tønnessen ◽  
O W Petersen ◽  
K Sandvig ◽  
S Olsnes
Keyword(s):  
Horseradish Peroxidase ◽  
Golgi Complex ◽  
Serial Section ◽  
Colloidal Gold ◽  
Vero Cells ◽  
Coated Vesicle ◽  
Electron Microscopical ◽  
Endosomal System ◽  
Section Analysis ◽  
Mcf 7

Receptor-mediated endocytosis and intracellular routing of native ricin, and of ricin conjugated to colloidal gold (Ri-Au) and to horseradish peroxidase (Ri-HRP), have been studied in cultured MCF-7 and Vero cells by electron microscopical techniques including serial section analysis. Both native ricin, as demonstrated by immunoperoxidase cytochemistry, and the ricin conjugates were internalized via a common coated pit-coated vesicle pathway to reach vacuolar and tubulo-vesicular portions of the endosomal system. In addition, native ricin and a purified monovalent fraction of Ri-HRP reached distinct Golgi cisterns, whereas Ri-Au and polyvalent Ri-HRP did not. The results delineate intracellular routing of native ricin and compare it with the routing of different ricin conjugates. Moreover, our study shows that conjugates of a particular ligand (ricin) and various probes (e.g., gold and peroxidase), may be handled differently by cells. Sorting apparently takes place in the endosomal system, allowing some but not other molecules to reach Golgi elements. This sorting seems to depend on the valency of the ricin conjugate.

Comparative strengths and weaknesses of peroxidase and colloidal gold in pre- and post-embedding immunolabeling techniques

1987 ◽  
Vol 45 ◽  
pp. 1002-1005
Author(s):  
D. R. Abrahamson ◽  
P. L. St.John ◽  
E. W. Perry
Keyword(s):  
Electron Microscopy ◽  
Horseradish Peroxidase ◽  
Light Microscopy ◽  
Colloidal Gold ◽  
Light Microscope ◽  
Ultrastructural Localization ◽  
The Other ◽  
Quantitative Studies ◽  
Dense Suspension ◽  
Antigen Localization

Antibodies coupled to tracers for electron microscopy have been instrumental in the ultrastructural localization of antigens within cells and tissues. Among the most popular tracers are horseradish peroxidase (HRP), an enzyme that yields an osmiophilic reaction product, and colloidal gold, an electron dense suspension of particles. Some advantages of IgG-HRP conjugates are that they are readily synthesized, relatively small, and the immunolabeling obtained in a given experiment can be evaluated in the light microscope. In contrast, colloidal gold conjugates are available in different size ranges and multiple labeling as well as quantitative studies can therefore be undertaken through particle counting. On the other hand, gold conjugates are generally larger than those of HRP but usually can not be visualized with light microscopy. Concern has been raised, however, that HRP reaction product, which is exquisitely sensitive when generated properly, may in some cases distribute to sites distant from the original binding of the conjugate and therefore result in spurious antigen localization.

Intralysosomal Accumulation of Colloidal Gold-Low Density Lipoprotein Conjugates in Chloroquine-Treated Fibroblasts

1985 ◽  
Vol 43 ◽  
pp. 546-547 ◽  
Author(s):  
Dean A. Handley ◽  
Cynthia M. Arbeeny ◽  
Larry D. Witte
Keyword(s):  
Colloidal Gold ◽  
Cultured Cells ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Coated Vesicle ◽  
Low Density ◽  
Cholesterol Esters ◽  
Cultured Fibroblasts ◽  
Surface Receptors ◽  
Ldl Particles

Low density lipoproteins (LDL) are the major cholesterol carrying particles in the blood. Using cultured cells, it has been shown that LDL particles interact with specific surface receptors and are internalized via a coated pit-coated vesicle pathway for lysosomal catabolism. This (Pathway has been visualized using LDL labeled to ferritin or colloidal gold. It is now recognized that certain lysomotropic agents, such as chloroquine, inhibit lysosomal enzymes that degrade protein and cholesterol esters. By interrupting cholesterol ester hydrolysis, chloroquine treatment results in lysosomal accumulation of cholesterol esters from internalized LDL. Using LDL conjugated to colloidal gold, we have examined the ultrastructural effects of chloroquine on lipoprotein uptake by normal cultured fibroblasts.

scholarly journals Bufadienolides from the Skin Secretions of the Neotropical Toad Rhinella alata (Anura: Bufonidae): Antiprotozoal Activity against Trypanosoma cruzi

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4217
Author(s):  
Candelario Rodriguez ◽  
Roberto Ibáñez ◽  
Luis Mojica ◽  
Michelle Ng ◽  
Carmenza Spadafora ◽  
...  
Keyword(s):  
Vero Cells ◽  
Chemical Diversity ◽  
Hydroxyl Group ◽  
Antitrypanosomal Activity ◽  
The Family ◽  
Toad Venom ◽  
Skin Secretions ◽  
Pharmacological Potential ◽  
First Time ◽  
Mcf 7

Toads in the family Bufonidae contain bufadienolides in their venom, which are characterized by their chemical diversity and high pharmacological potential. American trypanosomiasis is a neglected disease that affects an estimated 8 million people in tropical and subtropical countries. In this research, we investigated the chemical composition and antitrypanosomal activity of toad venom from Rhinella alata collected in Panama. Structural determination using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy led to the identification of 10 bufadienolides. Compounds identified include the following: 16β-hydroxy-desacetyl-bufotalin-3-adipoyl-arginine ester (1), bufotalin (2), 16β-hydroxy-desacetyl-bufotalin-3-pimeloyl-arginine ester (3), bufotalin-3-pimeloyl-arginine ester (4), 16β-hydroxy-desacetyl-bufotalin-3-suberoyl-arginine ester (5), bufotalin-3-suberoyl-arginine ester (6), cinobufagin-3-adipoyl-arginine ester (7), cinobufagin-3-pimeloyl-arginine ester (8), cinobufagin-3-suberoyl-arginine ester (9), and cinobufagin (10). Among these, three new natural products, 1, 3, and 5, are described, and compounds 1–10 are reported for the first time in R. alata. The antitrypanosomal activity assessed in this study revealed that the presence of an arginyl-diacid attached to C-3, and a hydroxyl group at C-14 in the structure of bufadienolides that is important for their biological activity. Bufadienolides showed cytotoxic activity against epithelial kidney Vero cells; however, bufagins (2 and 10) displayed low mammalian cytotoxicity. Compounds 2 and 10 showed activity against the cancer cell lines MCF-7, NCI-H460, and SF-268.

scholarly journals Flavonoids from Milletia leucantha and Their Cytotoxicity

2018 ◽  
Vol 13 (8) ◽  
pp. 1934578X1801300
Author(s):  
Uraiwan Sriphana ◽  
Chavi Yenjai ◽  
Siriporn Tungnoi ◽  
Jongjai Srirapa ◽  
Auemporn Junsongduang
Keyword(s):  
Cytotoxic Activity ◽  
Vero Cell ◽  
Cell Line ◽  
Vero Cells ◽  
2D Nmr ◽  
Nmr Techniques ◽  
Vero Cell Lines ◽  
First Time ◽  
Flavonol Derivatives ◽  
Mcf 7

Two known chalcones (1–2), five known flavonol derivatives (3 and 5–8) and one flavone (4) were isolated for the first time from fruits of Millettia leucantha Kurz. In addition, 5 was found for the first time from this genus. Their structures were elucidated on the basis of IR, MS, 1D and 2D NMR techniques. Chalcone 1 exhibited moderate cytotoxicity against the MCF-7 cell line with an IC50 value of 50.93 μM, whereas this compound showed inactive cytotoxicity against Vero cells. Compound 2 exhibited cytotoxicity against the KB, NCI-H187 and Vero cell lines with IC50 values of 63.64, 114.44 and 28.44 μM, respectively. Compound 8 only showed cytotoxic activity against the KB cell line with an IC50 value of 110.23 μM.

scholarly journals Polymorphism and Structural Maturation of Bunyamwera Virus in Golgi and Post-Golgi Compartments

2003 ◽  
Vol 77 (2) ◽  
pp. 1368-1381 ◽  
Author(s):  
Iñigo J. Salanueva ◽  
Reyes R. Novoa ◽  
Pilar Cabezas ◽  
Carmen López-Iglesias ◽  
José L. Carrascosa ◽  
...  
Keyword(s):  
Golgi Complex ◽  
Vero Cells ◽  
Productive Infection ◽  
Tubular Structures ◽  
Enveloped Viruses ◽  
Golgi Stack ◽  
Golgi Region ◽  
Viral Particles ◽  
Infected Cells ◽  
Bunyamwera Virus

ABSTRACT The Golgi apparatus is the assembly site for a number of complex enveloped viruses. Using high-preservation methods for electron microscopy, we have detected two previously unknown maturation steps in the morphogenesis of Bunyamwera virus in BHK-21 cells. The first maturation takes place inside the Golgi stack, where annular immature particles transform into dense, compact structures. Megalomicin, a drug that disrupts the trans side of the Golgi complex, reversibly blocks transformation, showing that a functional trans-Golgi is needed for maturation. The second structural change seems to take place during the egress of viral particles from cells, when a coat of round-shaped spikes becomes evident. A fourth viral assembly was detected in infected cells: rigid tubular structures assemble in the Golgi region early in infection and frequently connect with mitochondria. In Vero cells, the virus induces an early and spectacular fragmentation of intracellular membranes while productive infection progresses. Assembly occurs in fragmented Golgi stacks and generates tubular structures, as well as the three spherical viral forms. These results, together with our previous studies with nonrelated viruses, show that the Golgi complex contains key factors for the structural transformation of a number of enveloped viruses that assemble intracellularly.

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