Lipid Headgroup Charge Controls Melittin Oligomerization in Membranes: Implications in Membrane Lysis

2021 ◽  
Author(s):  
Sreetama Pal ◽  
Hirak Chakraborty ◽  
Amitabha Chattopadhyay
Keyword(s):  
Membrane Lysis

scholarly journals Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Amaranthus Tricolor ◽  
Core Motif ◽  
Gram Negative ◽  
E Coli ◽  
Membrane Lysis

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

scholarly journals Membrane lysis during biological membrane fusion: collateral damage by misregulated fusion machines

2008 ◽  
Vol 183 (2) ◽  
pp. 181-186 ◽  
Author(s):  
Alex Engel ◽  
Peter Walter
Keyword(s):  
Membrane Fusion ◽  
Biological Membrane ◽  
Membrane Integrity ◽  
Fusion Pore ◽  
Mechanistic Models ◽  
Collateral Damage ◽  
Vacuole Fusion ◽  
Membrane Lysis

In the canonical model of membrane fusion, the integrity of the fusing membranes is never compromised, preserving the identity of fusing compartments. However, recent molecular simulations provided evidence for a pathway to fusion in which holes in the membrane evolve into a fusion pore. Additionally, two biological membrane fusion models—yeast cell mating and in vitro vacuole fusion—have shown that modifying the composition or altering the relative expression levels of membrane fusion complexes can result in membrane lysis. The convergence of these findings showing membrane integrity loss during biological membrane fusion suggests new mechanistic models for membrane fusion and the role of membrane fusion complexes.

scholarly journals Association of newly synthesized islet prohormones with intracellular membranes.

1984 ◽  
Vol 99 (2) ◽  
pp. 418-424 ◽  
Author(s):  
B D Noe ◽  
M N Moran
Keyword(s):  
Secretory Granules ◽  
Gradient Centrifugation ◽  
Gel Filtration ◽  
Proteolytic Processing ◽  
Membrane Association ◽  
Freezing And Thawing ◽  
Ph Optimum ◽  
Intracellular Membranes ◽  
Membrane Lysis ◽  
Repeated Freezing

Results from recent studies have indicated that pancreatic islet prohormone converting enzymes are membrane-associated in islet microsomes and secretory granules. This observation, along with the demonstration that proglucagon is topologically segregated to the periphery within alpha cell secretory granules in several species, led us to investigate the possibility that newly synthesized islet prohormones might be associated with intracellular membranes. Anglerfish islets were incubated with [3H]tryptophan and [14C]isoleucine for 3 h, then fractionated by differential and density gradient centrifugation. Microsome (M) and secretory granule (SG) fractions were halved, sedimented, and resuspended in the presence or absence of dissociative reagents. After membrane lysis by repeated freezing and thawing, the membranous and soluble components were separated by centrifugation. Extracts of supernatants and pellets were chromatographed by gel filtration; fractions were collected and counted. A high proportion (77-79%) of the newly synthesized proinsulin and insulin was associated with both M and SG membranes. Most of the newly synthesized proglucagons and prosomatostatins (12,000-mol-wt precursors) were also membrane-associated (86-88%) in M and SG. In contrast, glucagon- and somatostatin-related peptides exhibited much less membrane-association in SG (24-31%). Bacitracin, bovine serum albumin EDTA, RNAse, alpha-methylmannoside, N-acetylglucosamine, and dithiodipyridine had no effect on prohormone association with membranes. However, high salt (1 M KCl) significantly reduced membrane-association of prohormones. Binding of labeled prohormones to SG membranes from unlabeled tissue increased with incubation time and was inhibited by unlabeled prohormones. The pH optimum for prohormone binding to both M and SG membranes was 5.2. It is suggested that association of newly synthesized prohormones with intracellular membranes could be related to the facilitation of proteolytic processing of prohormones and/or transport from their site of synthesis to the secretory granules.

Continuous nucleus extraction by optically-induced cell lysis on a batch-type microfluidic platform

Lab on a Chip ◽  
2016 ◽  
Vol 16 (8) ◽  
pp. 1447-1456 ◽  
Author(s):  
Shih-Hsuan Huang ◽  
Lien-Yu Hung ◽  
Gwo-Bin Lee
Keyword(s):  
Cell Membrane ◽  
Extraction Efficiency ◽  
Cell Lysis ◽  
Microfluidic Platform ◽  
Batch Type ◽  
Membrane Lysis ◽  
Optically Induced

An innovative, microfluidics-based approach featuring optically-induced cell lysis (OICL) for nucleus extraction and collection in an automatic format was demonstrated. The efficiency of cell membrane lysis and the ODEP nucleus separation was measured to be 78.04 ± 5.70% and 80.90 ± 5.98%, respectively, leading to an overall nucleus extraction efficiency of 58.21 ± 2.21%.

scholarly journals Membrane Insertion ofEscherichia coliα-Hemolysin Is Independent from Membrane Lysis

2005 ◽  
Vol 281 (9) ◽  
pp. 5461-5467 ◽  
Author(s):  
Lissete Sánchez-Magraner ◽  
Aitziber L. Cortajarena ◽  
Félix M. Goñi ◽  
Helena Ostolaza
Keyword(s):  
Membrane Insertion ◽  
Membrane Lysis

scholarly journals A scientific validation of In vitro anti-inflammatory activity of Punica granatum L. by human red blood cell membrane stabilization

2018 ◽  
Vol 6 (7) ◽  
pp. 2430
Author(s):  
Karunakar Kota ◽  
Sandhya Sharma ◽  
Jameela Tahashildar
Keyword(s):  
Methanolic Extract ◽  
Punica Granatum ◽  
Inflammatory Activity ◽  
Membrane Stabilization ◽  
Fruit Peel ◽  
Standard Drug ◽  
Membrane Lysis ◽  
Anti Inflammatory ◽  
Punica Granatum L

Background: In recent years there has been growing interest in therapeutic use of natural products, especially those derived from plants. P. granatum is very common dietary ingredient in many parts of India and has remarkable biological and medicinal properties.Methods: In the present study, the methanolic extract of fruit peels of Punica granatum Linn. (MEPG) were investigated for anti-inflammatory activity by simple, reliable, less toxic and less time consuming HRBC membrane stabilization method. The presentation of hypo tonicity induced HRBC membrane lysis was taken a measure of anti-inflammatory activity. Their activities were compared with standard drug diclofenac.Results: The results of the study demonstrated that P. granatum contains active constituents, which possess anti-inflammatory activity which is probably related to the inhibition of prostaglandin synthesis.Conclusions: It is concluded that methanolic extract of P. granatum fruit peel possesses significant anti-inflammatory activity and this is a possible rationale for its folkloric use as an anti-inflammatory agent.

Sign in / Sign up

Export Citation Format

Share Document