Senescent Erythrocytes Exhibit a Single-Hit Response to Staphylococcal Alpha Toxin

Gerontology ◽  
1997 ◽  
Vol 44 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Lana Kantor ◽  
Hugh B. Fackrell
Keyword(s):  
Alpha Toxin ◽  
Senescent Erythrocytes

Immobilization of alpha toxin on the surface of the bacillus subtilis spores

2016 ◽  
Vol 1 (3) ◽  
pp. 0-0
Author(s):  
Amin Rostami ◽  
Fatemeh Goshadrou ◽  
Gholamreza Ahmadian
Keyword(s):  
Bacillus Subtilis ◽  
Alpha Toxin

scholarly journals Hemolysis in the spleen drives erythrocyte turnover

Blood ◽  
2020 ◽  
Author(s):  
Thomas robert leon Klei ◽  
Jill Jasmine Dalimot ◽  
Benjamin Nota ◽  
Martijn Veldthuis ◽  
Erik Mul ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Matrix Proteins ◽  
Human Spleen ◽  
Erythrocyte Adhesion ◽  
Subsequent Degradation ◽  
Macrophage Subpopulations ◽  
Senescent Erythrocytes ◽  
Red Pulp

Red pulp macrophages of the spleen mediate turnover of billions of senescent erythrocytes per day. However, the molecular mechanisms involved in sequestration of senescent erythrocytes, their recognition and their subsequent degradation by red pulp macrophages remain unclear. In this study we provide evidence that the splenic environment is of substantial importance in facilitating erythrocyte turnover through induction of hemolysis. Upon isolating human spleen red pulp macrophages we noted a substantial lack of macrophages that were in the process of phagocytosing intact erythrocytes. Detailed characterization of erythrocyte and macrophage subpopulations from human spleen tissue led to the identification of erythrocytes that are devoid of hemoglobin, so-called erythrocyte ghosts. By in vivo imaging and transfusion experiments we further confirmed that senescent erythrocytes that are retained in the spleen are subject to hemolysis. Additionally, we show that erythrocyte adhesion molecules, which are specifically activated on aged erythrocytes, cause senescent erythrocytes to interact with extracellular matrix proteins that are exposed within the splenic architecture. Such adhesion molecule-driven retention of senescent erythrocytes, under low shear conditions, was found to result in steady shrinkage of the cell and ultimately resulted in hemolysis. In contrast to intact senescent erythrocytes, the remnant erythrocyte ghost shells were prone to recognition and breakdown by red pulp macrophages. These data identify hemolysis as a key event in the turnover of senescent erythrocytes, which alters our current understanding of how erythrocyte degradation is regulated.

Regulation of Ca2+ sensitivity in alpha-toxin skinned smooth muscle

1992 ◽  
Vol 24 ◽  
pp. 36
Author(s):  
Cornelis van Breemen ◽  
Junji Nishimura ◽  
Suzanne Moreland ◽  
Robert S. Moreland
Keyword(s):  
Smooth Muscle ◽  
Alpha Toxin ◽  
Skinned Smooth Muscle

Activation and mechanism of Clostridium septicum alpha toxin

1993 ◽  
Vol 10 (3) ◽  
pp. 627-634 ◽  
Author(s):  
J. Ballard ◽  
Y. Sokolov ◽  
W.-L. Yuan ◽  
B. L. Kagan ◽  
R. K. Tweten
Keyword(s):  
Alpha Toxin ◽  
Clostridium Septicum

scholarly journals Perfringolysin O Expression in Clostridium perfringens Is Independent of the Upstream pfoR Gene

2002 ◽  
Vol 184 (7) ◽  
pp. 2034-2038 ◽  
Author(s):  
Milena M. Awad ◽  
Julian I. Rood
Keyword(s):  
Escherichia Coli ◽  
Homologous Recombination ◽  
Gene Product ◽  
Structural Gene ◽  
Clostridium Perfringens ◽  
Deletion Mutant ◽  
Gas Gangrene ◽  
Alpha Toxin ◽  
Clostridial Myonecrosis ◽  
Perfringolysin O

ABSTRACT The pathogenesis of Clostridium perfringens-mediated gas gangrene or clostridial myonecrosis involves the extracellular toxins alpha-toxin and perfringolysin O. Previous studies (T. Shimizu, A. Okabe, J. Minami, and H. Hayashi, Infect. Immun. 59:137-142, 1991) carried out with Escherichia coli suggested that the perfringolysin O structural gene, pfoA, was positively regulated by the product of the upstream pfoR gene. In an attempt to confirm this hypothesis in C. perfringens, a pfoR-pfoA deletion mutant was complemented with isogenic pfoA+ shuttle plasmids that varied only in their ability to encode an intact pfoR gene. No difference in the ability to produce perfringolysin O was observed for C. perfringens strains carrying these plasmids. In addition, chromosomal pfoR mutants were constructed by homologous recombination in C. perfringens. Again no difference in perfringolysin O activity was observed. Since it was not possible to alter perfringolysin O expression by mutation of pfoR, it was concluded that the pfoR gene product is unlikely to have a role in the regulation of pfoA expression in C. perfringens.

A Field Study of Naturally Occurring Specific Antibodies against Clostridium perfringens Alpha Toxin in Norwegian Broiler Flocks

2001 ◽  
Vol 45 (3) ◽  
pp. 724 ◽  
Author(s):  
B. T. Heier ◽  
A. Lovland ◽  
K. B. Soleim ◽  
M. Kaldhusal ◽  
J. Jarp
Keyword(s):  
Field Study ◽  
Clostridium Perfringens ◽  
Alpha Toxin ◽  
Specific Antibodies ◽  
Naturally Occurring
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