Bacterial cell membrane hydrolysis by secreted phospholipases A2: a major physiological role of human group IIa sPLA2 involving both bacterial cell wall penetration and interfacial catalysis

Author(s):  
Andrew G Buckland ◽  
Emma L Heeley ◽  
David C Wilton
RSC Advances ◽  
2015 ◽  
Vol 5 (81) ◽  
pp. 66476-66486 ◽  
Author(s):  
Dibyendu Das ◽  
Sumyra Sidiq ◽  
Santanu Kumar Pal

Liquid crystals offer a promising approach to study and quantify the interactions between different bacterial cell membrane components with endotoxin at an aqueous interface.


2005 ◽  
Vol 49 (3) ◽  
pp. 1127-1134 ◽  
Author(s):  
Deborah L. Higgins ◽  
Ray Chang ◽  
Dmitri V. Debabov ◽  
Joey Leung ◽  
Terry Wu ◽  
...  

ABSTRACTThe emergence and spread of multidrug-resistant gram-positive bacteria represent a serious clinical problem. Telavancin is a novel lipoglycopeptide antibiotic that possesses rapid in vitro bactericidal activity against a broad spectrum of clinically relevant gram-positive pathogens. Here we demonstrate that telavancin's antibacterial activity derives from at least two mechanisms. As observed with vancomycin, telavancin inhibited late-stage peptidoglycan biosynthesis in a substrate-dependent fashion and bound the cell wall, as it did the lipid II surrogate tripeptideN,N′-diacetyl-l-lysinyl-d-alanyl-d-alanine, with high affinity. Telavancin also perturbed bacterial cell membrane potential and permeability. In methicillin-resistantStaphylococcus aureus, telavancin caused rapid, concentration-dependent depolarization of the plasma membrane, increases in permeability, and leakage of cellular ATP and K+. The timing of these changes correlated with rapid , concentration-dependent loss of bacterial viability, suggesting that the early bactericidal activity of telavancin results from dissipation of cell membrane potential and an increase in membrane permeability. Binding and cell fractionation studies provided direct evidence for an interaction of telavancin with the bacterial cell membrane; stronger binding interactions were observed with the bacterial cell wall and cell membrane relative to vancomycin. We suggest that this multifunctional mechanism of action confers advantageous antibacterial properties.


1965 ◽  
Vol 18 (3) ◽  
pp. 563 ◽  
Author(s):  
PA Trudinger

Freshly prepared cells of T. neapolitanus had an effective thiosulphate-impermeable volume of 2�21 ml/g dry weight; on treatment of the bacteria with n-butanol this value fell to O� 86 ml/g dry weight. T. neapolitanus catalysed an exchange of sulphur between sulphite and the inner-sulphur group of thiosulphate although the bacteria appeared to be impermeable to sulphite. The exchange reaction was inhibited by N-ethylmaleimide and iodoacetamide. No accumulation of the substrate or products within the bacterial cell occurred during the oxidation of thiosulphate. It is concluded that thiosulphate sulphur enters the bacterial cell by a process other than simple diffusion and that the exchange between sulphite and thiosulphate takes place at the bacterial cell membrane. A possible role of sulphenyl derivatives in the uptake of thiosulphate is discussed.


2002 ◽  
Vol 22 (1-2) ◽  
pp. 209-222 ◽  
Author(s):  
Bénédicte Flambard

Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 543
Author(s):  
Ozioma F. Nwabor ◽  
Sukanlaya Leejae ◽  
Supayang P. Voravuthikunchai

As the burden of antibacterial resistance worsens and treatment options become narrower, rhodomyrtone—a novel natural antibiotic agent with a new antibacterial mechanism—could replace existing antibiotics for the treatment of infections caused by multi-drug resistant Gram-positive bacteria. In this study, rhodomyrtone was detected within the cell by means of an easy an inexpensive method. The antibacterial effects of rhodomyrtone were investigated on epidemic methicillin-resistant Staphylococcus aureus. Thin-layer chromatography demonstrated the entrapment and accumulation of rhodomyrtone within the bacterial cell wall and cell membrane. The incorporation of radiolabelled precursors revealed that rhodomyrtone inhibited the synthesis of macromolecules including DNA, RNA, proteins, the cell wall, and lipids. Following the treatment with rhodomyrtone at MIC (0.5–1 µg/mL), the synthesis of all macromolecules was significantly inhibited (p ≤ 0.05) after 4 h. Inhibition of macromolecule synthesis was demonstrated after 30 min at a higher concentration of rhodomyrtone (4× MIC), comparable to standard inhibitor compounds. In contrast, rhodomyrtone did not affect lipase activity in staphylococci—both epidemic methicillin-resistant S. aureus and S. aureus ATCC 29213. Interfering with the synthesis of multiple macromolecules is thought to be one of the antibacterial mechanisms of rhodomyrtone.


1991 ◽  
Vol 260 (2) ◽  
pp. G213-G219 ◽  
Author(s):  
R. A. DeLa Cadena ◽  
K. J. Laskin ◽  
R. A. Pixley ◽  
R. B. Sartor ◽  
J. H. Schwab ◽  
...  

The plasma kallikrein-kinin system is activated in Gram-negative sepsis and typhoid fever, two diseases in which bacterial products have been shown to initiate inflammation. Because a single intraperitoneal injection of bacterial cell wall peptidoglycan-polysaccharide polymers from group A steptococci (PG-APS) into a Lewis rat produces a syndrome of relapsing polyarthritis and anemia, we investigated changes in the role of the kallikrein-kinin system in this model of inflammation. Coagulation studies after injection of PG-APS revealed an immediate and persistent decrease in prekallikrein levels. High-molecular-weight kininogen levels decreased significantly during the acute phase and correlated with the severity of arthritis. Factor XI levels were decreased only during the acute phase. Antithrombin III levels remained unchanged, indicating that neither decreased hepatic synthesis nor disseminated intravascular coagulation caused the decreased plasma contact factors. Plasma T-kininogen (an acute phase protein) was significantly elevated during the chronic phase. PG-APS failed to activate the contact system in vitro. Thus the kallikrein-kinin system plays an important role in this experimental model of inflammation, suggesting that activation of this system may play a role in the pathogenesis of inflammatory bowel disease and rheumatoid arthritis in which bacterial products might be etiologically important.


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