Suspension Anti-Streptolysin-O (ASO/ASL) Test

<p>Cholesterol-dependent cytolysins (CDCs) are proteinaceous toxins secreted as monomers by some Gram-positive and Gram-negative bacteria that contribute to their pathogenicity. These toxins bind to either cholesterol or human CD59, leading to massive structural changes, toxin oligomerization, formation of very large pores, and ultimately cell death, making these proteins promising targets for inhibition. Myricetin, and its related flavonoids, have been previously identified as a candidate small molecule inhibitor of specific CDCs such as listeriolysin O (LLO) and suilysin (SLY), interfering with their oligomerization. In this work, molecular docking was performed to assess the interaction of myricetin with other CDCs whose crystal structures are already known. Results indicated that although myricetin bound to the hitherto identified cavity in domain 4 (D4), much more efficient and stable binding was obtained in sites along the interfacial regions of domains 1 – 3 (D1 – D3). This was common among the tested CDCs, which was primarily due to much more extensive stabilizing intermolecular interactions, as indicated by post-docking analysis. Specifically, myricetin bound to (1) the interface of the three domains in anthrolysin O (ALO), perfringolysin O (PFO), pneumolysin (PLY), SLY, and vaginolysin (VLY), (2) at/near the D1/D3 interface in LLO and streptolysin O (SLO), and (3) along the D2/D3 interface in intermedilysin (ILY). These findings provide theoretical basis on the possibility of using myricetin and its related compounds as a broad-spectrum inhibitor of CDCs to potentially address the diseases associated with these pathogens.</p>

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Trafficking and Association of Plasmodium falciparum MC-2TM with the Maurer’s Clefts

Pathogens ◽

10.3390/pathogens10040431 ◽

2021 ◽

Vol 10 (4) ◽

pp. 431

Author(s):

Raghavendra Yadavalli ◽

John W. Peterson ◽

Judith A. Drazba ◽

Tobili Y. Sam-Yellowe

Keyword(s):

Plasmodium Falciparum ◽

Erythrocyte Membrane ◽

Sodium Carbonate ◽

Infected Erythrocyte ◽

Brefeldin A ◽

Specific Expression ◽

Lipid Interactions ◽

And Topology ◽

Streptolysin O ◽

Maurer's Clefts

In this study, we investigated stage specific expression, trafficking, solubility and topology of endogenous PfMC-2TM in P. falciparum (3D7) infected erythrocytes. Following Brefeldin A (BFA) treatment of parasites, PfMC-2TM traffic was evaluated using immunofluorescence with antibodies reactive with PfMC-2TM. PfMC-2TM is sensitive to BFA treatment and permeabilization of infected erythrocytes with streptolysin O (SLO) and saponin, showed that the N and C-termini of PfMC-2TM are exposed to the erythrocyte cytoplasm with the central portion of the protein protected in the MC membranes. PfMC-2TM was expressed as early as 4 h post invasion (hpi), was tightly colocalized with REX-1 and trafficked to the erythrocyte membrane without a change in solubility. PfMC-2TM associated with the MC and infected erythrocyte membrane and was resistant to extraction with alkaline sodium carbonate, suggestive of protein-lipid interactions with membranes of the MC and erythrocyte. PfMC-2TM is an additional marker of the nascent MCs.

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Liposomes Prevent In Vitro Hemolysis Induced by Streptolysin O and Lysenin

Membranes ◽

10.3390/membranes11050364 ◽

2021 ◽

Vol 11 (5) ◽

pp. 364

Author(s):

Marcelo Ayllon ◽

Gamid Abatchev ◽

Andrew Bogard ◽

Rosey Whiting ◽

Sarah E. Hobdey ◽

...

Keyword(s):

Blood Cell ◽

Lipid Membranes ◽

Bilayer Lipid Membranes ◽

Prior Work ◽

Cellular Targets ◽

Toxin Binding ◽

Streptolysin O ◽

Biological Attack ◽

Toxin Removal

The need for alternatives to antibiotics in the fight against infectious diseases has inspired scientists to focus on antivirulence factors instead of the microorganisms themselves. In this respect, prior work indicates that tiny, enclosed bilayer lipid membranes (liposomes) have the potential to compete with cellular targets for toxin binding, hence preventing their biological attack and aiding with their clearance. The effectiveness of liposomes as decoy targets depends on their availability in the host and how rapidly they are cleared from the circulation. Although liposome PEGylation may improve their circulation time, little is known about how such a modification influences their interactions with antivirulence factors. To fill this gap in knowledge, we investigated regular and long-circulating liposomes for their ability to prevent in vitro red blood cell hemolysis induced by two potent lytic toxins, lysenin and streptolysin O. Our explorations indicate that both regular and long-circulating liposomes are capable of similarly preventing lysis induced by streptolysin O. In contrast, PEGylation reduced the effectiveness against lysenin-induced hemolysis and altered binding dynamics. These results suggest that toxin removal by long-circulating liposomes is feasible, yet dependent on the particular virulence factor under scrutiny.

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Gs is the major G protein involved in interleukin-2-activated natural killer (IANK) cell-mediated cytotoxicity. Successful introduction of anti-G protein antibodies inside streptolysin O-permeabilized IANK cells.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)37446-x ◽

1994 ◽

Vol 269 (9) ◽

pp. 6796-6802

Author(s):

A.A. Maghazachi ◽

A. Al-Aoukaty

Keyword(s):

Natural Killer ◽

G Protein ◽

Interleukin 2 ◽

Streptolysin O

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Single-chain variable fragment (scFv) targeting streptolysin O controls group A Streptococcus infection

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2021.06.021 ◽

2021 ◽

Vol 566 ◽

pp. 177-183

Author(s):

Chihiro Aikawa ◽

Kiyosumi Kawashima ◽

Chihiro Fukuzaki ◽

Makoto Nakakido ◽

Kazunori Murase ◽

...

Keyword(s):

Group A Streptococcus ◽

Single Chain Variable Fragment ◽

Single Chain ◽

Streptolysin O ◽

Group A

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Exocytosis from permeabilized bovine adrenal chromaffin cells is differently modulated by guanosine 5′-[γ-thio]triphosphate and guanosine 5′-[β γ-imido]triphosphate. Evidence for the involvement of various guanine nucleotide-binding proteins

Biochemical Journal ◽

10.1042/bj2840321 ◽

1992 ◽

Vol 284 (2) ◽

pp. 321-326 ◽

Cited By ~ 27

Author(s):

G Ahnert-Hilger ◽

U Wegenhorst ◽

B Stecher ◽

K Spicher ◽

W Rosenthal ◽

...

Keyword(s):

G Protein ◽

Chromaffin Cells ◽

Inhibitory Effect ◽

Adrenal Chromaffin Cells ◽

Prolonged Incubation ◽

Permeabilized Cells ◽

Alpha Subunits ◽

Cytoplasmic Material ◽

Streptolysin O ◽

Adrenal Chromaffin

1. In bovine adrenal chromaffin cells made permeable either to molecules less than or equal to 3 kDa with alphatoxin or to proteins less than or equal to 150 kDa with streptolysin O, the GTP analogues guanosine 5′-[beta gamma-imido]triphosphate (p[NH]ppG) and guanosine 5′-[gamma-thio]triphosphate (GTP[S]) differently modulated Ca(2+)-stimulated exocytosis. 2. In alphatoxin-permeabilized cells, p[NH]ppG up to 20 microM activated Ca(2+)-stimulated exocytosis. Higher concentrations had little or no effect. At a free Ca2+ concentration of 5 microM, 7 microM-p[NH]ppG stimulated exocytosis 6-fold. Increasing the free Ca2+ concentration reduced the effect of p[NH]ppG. Pretreatment of the cells with pertussis toxin prevented the activation of the Ca(2+)-stimulated exocytosis by p[NH]ppG. 3. In streptolysin O-permeabilized cells, p[NH]ppG did not activate, but rather inhibited Ca(2+)-dependent catecholamine release under all conditions studied. In the soluble cytoplasmic material that escaped during permeabilization with streptolysin O, different G-protein alpha-subunits were detected using an appropriate antibody. Around 15% of the cellular alpha-subunits were detected in the supernatant of permeabilized control cells. p[NH]ppG or GTP[S] stimulated the release of alpha-subunits 2-fold, causing a loss of about 30% of the cellular G-protein alpha-subunits under these conditions. Two of the alpha-subunits in the supernatant belonged to the G(o) type, as revealed by an antibody specific for G(o) alpha. 4. GTP[S], when present alone during stimulation with Ca2+, activated exocytosis in a similar manner to p[NH]ppG. Upon prolonged incubation, GTP[S], in contrast to p[NH]ppG, inhibited Ca(2+)-induced exocytosis from cells permeabilized by either of the pore-forming toxins. This effect was resistant to pertussin toxin. 5. The p[NH]ppG-induced activation of Ca(2+)-stimulated release from alphatoxin-permeabilized chromaffin cells may be attributed to one of the heterotrimeric G-proteins lost during permeabilization with streptolysin O. The inhibitory effect of GTP[S] on exocytosis is apparently not mediated by G-protein alpha-subunits, but by another GTP-dependent process still occurring after permeabilization with streptolysin O.

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