scholarly journals Curcumin activation of a bacterial mechanosensitive channel underlies its membrane permeability and adjuvant properties

2021 ◽  
Vol 17 (12) ◽  
pp. e1010198
Author(s):  
Robin Wray ◽  
Irene Iscla ◽  
Paul Blount
Keyword(s):  
Membrane Permeability ◽  
Natural Compound ◽  
Bacterial Species ◽  
Antibacterial Properties ◽  
Cell Lysis ◽  
Membrane Permeabilization ◽  
Mechanosensitive Channel ◽  
Bacterial Membrane ◽  
Physiological Effects ◽  
Membrane Tension

Curcumin, a natural compound isolated from the rhizome of turmeric, has been shown to have antibacterial properties. It has several physiological effects on bacteria including an apoptosis-like response involving RecA, membrane permeabilization, inhibiting septation, and it can also work synergistically with other antibiotics. The mechanism by which curcumin permeabilizes the bacterial membrane has been unclear. Most bacterial species contain a Mechanosensitive channel of large conductance, MscL, which serves the function of a biological emergency release valve; these large-pore channels open in response to membrane tension from osmotic shifts and, to avoid cell lysis, allow the release of solutes from the cytoplasm. Here we show that the MscL channel underlies the membrane permeabilization by curcumin as well as its synergistic properties with other antibiotics, by allowing access of antibiotics to the cytoplasm; MscL also appears to have an inhibitory role in septation, which is enhanced when activated by curcumin.

scholarly journals Characterization of Cell Lysis in Pseudomonas putida Induced upon Expression of Heterologous Killing Genes

1998 ◽  
Vol 64 (12) ◽  
pp. 4904-4911 ◽  
Author(s):  
M. Carmen Ronchel ◽  
Lázaro Molina ◽  
Angela Witte ◽  
Werner Lutbiz ◽  
Søren Molin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Pseudomonas Putida ◽  
Membrane Permeability ◽  
Cell Lysis ◽  
Physiological Effects ◽  
Extracellular Medium ◽  
Biological Containment ◽  
Potential Applications

ABSTRACT Active biological containment systems are based on the controlled expression of killing genes. These systems are of interest for thePseudomonadaceae because of the potential applications of these microbes as bioremediation agents and biopesticides. The physiological effects that lead to cell death upon the induction of expression of two different heterologous killing genes in nonpathogenicPseudomonas putida KT2440 derivatives have been analyzed.P. putida CMC4 and CMC12 carry in their chromosomes a fusion of the PA1-04/03 promoter to the Escherichia coli gef gene and the φX174 lysis gene E, respectively. Expression of the killing genes is controlled by the LacI protein, whose expression is initiated from the XylS-dependent Pm promoter. Under induced conditions, killing of P. putidaCMC12 cells mediated by φX174 lysis protein E was faster than that observed for P. putida CMC4, for which the Gef protein was the killing agent. In both cases, cell death occurred as a result of impaired respiration, altered membrane permeability, and the release of some cytoplasmic contents to the extracellular medium.

scholarly journals Curcumin: Modern Applications for a Versatile Additive

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 519
Author(s):  
Florentina Monica Raduly ◽  
Valentin Raditoiu ◽  
Alina Raditoiu ◽  
Violeta Purcar
Keyword(s):  
Bacterial Infections ◽  
Natural Compound ◽  
Review Paper ◽  
Curcuma Longa ◽  
Antibacterial Properties ◽  
Point Of View ◽  
Nano Particles ◽  
Synergistic Activity ◽  
Quality Of Food

The recent development of several methods for extracting curcumin from the root of the plant Curcuma longa has led to intensified research on the properties of curcumin and its fields of application. Following the studies and the accreditation of curcumin as a natural compound with antifungal, antiviral, and antibacterial properties, new fields of application have been developed in two main directions—food and medical, respectively. This review paper aims to synthesize the fields of application of curcumin as an additive for the prevention of spoilage, safety, and quality of food. Simultaneously, it aims to present curcumin as an additive in products for the prevention of bacterial infections and health care. In both cases, the types of curcumin formulations in the form of (nano)emulsions, (nano)particles, or (nano)composites are presented, depending on the field and conditions of exploitation or their properties to be used. The diversity of composite materials that can be designed, depending on the purpose of use, leaves open the field of research on the conditioning of curcumin. Various biomaterials active from the antibacterial and antibiofilm point of view can be intuited in which curcumin acts as an additive that potentiates the activities of other compounds or has a synergistic activity with them.

scholarly journals Microbial Photoinactivation by Visible Light Results in Limited Loss of Membrane Integrity

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 341
Author(s):  
Katharina Hoenes ◽  
Richard Bauer ◽  
Barbara Spellerberg ◽  
Martin Hessling
Keyword(s):  
Visible Light ◽  
Pseudomonas Fluorescens ◽  
Bacterial Cell ◽  
Bacterial Species ◽  
Membrane Integrity ◽  
Cell Lysis ◽  
Microbial Inactivation ◽  
Bacterial Cells ◽  
Resistance Development ◽  
Transmission Electron

Interest in visible light irradiation as a microbial inactivation method has widely increased due to multiple possible applications. Resistance development is considered unlikely, because of the multi-target mechanism, based on the induction of reactive oxygen species by wavelength specific photosensitizers. However, the affected targets are still not completely identified. We investigated membrane integrity with the fluorescence staining kit LIVE/DEAD® BacLight™ on a Gram positive and a Gram negative bacterial species, irradiating Staphylococcus carnosus and Pseudomonas fluorescens with 405 nm and 450 nm. To exclude the generation of viable but nonculturable (VBNC) bacterial cells, we applied an ATP test, measuring the loss of vitality. Pronounced uptake of propidium iodide was only observed in Pseudomonas fluorescens at 405 nm. Transmission electron micrographs revealed no obvious differences between irradiated samples and controls, especially no indication of an increased bacterial cell lysis could be observed. Based on our results and previous literature, we suggest that visible light photoinactivation does not lead to rapid bacterial cell lysis or disruption. However, functional loss of membrane integrity due to depolarization or inactivation of membrane proteins may occur. Decomposition of the bacterial envelope following cell death might be responsible for observations of intracellular component leakage.

Effect of Silver Ions on the Structural and Antibacterial Properties of Bone Replacement Material

2013 ◽  
Vol 795 ◽  
pp. 692-696 ◽  
Author(s):  
Nida Iqbal ◽  
Mohammed Rafiq Abdul Kadir ◽  
Nasrul Humaimi Bin Mahmood ◽  
Micheal Moses ◽  
Mashitah Binti Mad Salim ◽  
...  
Keyword(s):  
Calcium Phosphates ◽  
Bacterial Species ◽  
Calcium Nitrate ◽  
Antibacterial Properties ◽  
Silver Ions ◽  
Antibacterial Activities ◽  
Silver Addition ◽  
Wide Range ◽  
Microbial Infections ◽  
Inorganic Mineral

Antibacterial materials based on calcium phosphates have wide range of biomedical applications in the prevention of microbial infections. The synthesis of inorganic mineral component of bone i.e. hydroxyapatite was done with the addition of silver (Ag) (5-15 wt %) as antibacterial agent. The wet precipitation synthesis was carried out using diammonium hydrogen phosphate and calcium nitrate as P and Ca precursors. The presence and effect of silver addition on the structure was studied using Fourier Transform-Infrared (FTIR) spectroscopy and Energy Dispersive X-ray (EDX) techniques. The antibacterial properties of all samples were evaluated using Disc Diffusion Technique (DDT) againstS. aureus,B. subtilis, P. aeruginosaandE. coli. Antibacterial activities of samples were found to vary depending on the bacterial species and Ag loading percentage. The antibacterial assay suggested that the addition of Ag ions within hydroxyapatite can be effectively provided the required level of antibacterial activity against bacteria.

MEMBRANE-ACTIVE METHANOLIC CRUDE EXTRACT OF THERMOTOLERANT, Aspergillus fumigatus SSH01 AND ITS MODE OF ACTION AGAINST GRAM-POSITIVE PATHOGENS

2017 ◽  
Vol 80 (1) ◽  
Author(s):  
Mohamad Khairil Radzali ◽  
Akmal Hayat Abdul Karim ◽  
Syahida Ahmad ◽  
Wan Zuhainis Saad
Keyword(s):  
Aspergillus Fumigatus ◽  
Crude Extract ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Antibacterial Properties ◽  
Bacterial Membrane ◽  
Antibacterial Effects ◽  
Gram Positive ◽  
Bacillus Subtilis Atcc ◽  
Time Kill

This study was undertaken to investigate the antibacterial properties and the mode of actions of crude extract of Aspergillus fumigatus SSH01. Antibacterial properties was observed against Gram-positive pathogens and showed inhibition against Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538, methicillin-resistant S. aureus S547 (MRSA) and Listeria monocytogenes L10 with minimum inhibitory concentration (MIC, 0.097- 12.5 mg/ml) and minimum bactericidal concentration (MBC, 0.195 – 25 mg/ml). No surviving cells were detected after 15 h of treatment with the 2MIC of extracts for time-kill assay. Leakage of cellular contents of the treated test pathogens were identified and increased as the concentrations of the extracts increased. The study of morphological surface has shown the bacterial membrane was disrupted and caused loss of viability. This implies the antibacterial effects of A. fumigatus SSH01 extract may serve as the potential antibiotic. 

An investigation of antibacterial activity of New Zealand seaweed-associated marine bacteria

2021 ◽  
Author(s):  
Mehrnoush Tangestani ◽  
Paul Broady ◽  
Arvind Varsani
Keyword(s):  
New Zealand ◽  
Biomedical Application ◽  
Bacterial Species ◽  
Antibacterial Properties ◽  
Antagonistic Activity ◽  
Marine Macroalgae ◽  
Diffusion Method ◽  
Rrna Gene ◽  
Associated Bacteria ◽  
Phylogenetic Identification

Aim: To explore seaweed-associated bacteria as prospective producers of bioactive material with antibacterial properties. Materials & methods: 143 bacterial species were isolated from the surface of 15 New Zealand marine macroalgae. Bacterial extracts obtained using dimethyl sulfoxide and ethyl acetate were screened for antagonistic activities against three antimicrobial susceptibility indicators: Kocuria rhizophila, Staphylococcus epidermidis and Escherichia coli, using well-diffusion method. For selected species, minimum inhibitory concentration was determined, followed by a phylogenetic identification based on 16S rRNA gene sequences. Results: Among all bacteria screened, seven that belonged to the genera Vibrio, Pseudoalteromonas, Psychromonas and Cobetia, showed antagonistic activity against all three indicators. Conclusion: Seaweed-associated bacteria produce bioactive compounds with antimicrobial potential and possible biomedical application in aquatic habitats.

scholarly journals The Purified Mechanosensitive Channel TREK-1 Is Directly Sensitive to Membrane Tension

2013 ◽  
Vol 288 (38) ◽  
pp. 27307-27314 ◽  
Author(s):  
Catherine Berrier ◽  
Alexandre Pozza ◽  
Agnes de Lacroix de Lavalette ◽  
Solenne Chardonnet ◽  
Agnes Mesneau ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Mechanosensitive Channel ◽  
Positive Pressure ◽  
Mechanosensitive Channels ◽  
Membrane Tension ◽  
Animal Cells ◽  
Patch Clamp Recording ◽  
Electrophysiological Properties ◽  
Pressure Suction ◽  
Pore Domain

Mechanosensitive channels are detected in all cells and are speculated to play a key role in many functions including osmoregulation, growth, hearing, balance, and touch. In prokaryotic cells, a direct gating of mechanosensitive channels by membrane tension was clearly demonstrated because the purified channels could be functionally reconstituted in a lipid bilayer. No such evidence has been presented yet in the case of mechanosensitive channels from animal cells. TREK-1, a two-pore domain K+ channel, was the first animal mechanosensitive channel identified at the molecular level. It is the target of a large variety of agents such as volatile anesthetics, neuroprotective agents, and antidepressants. We have produced the mouse TREK-1 in yeast, purified it, and reconstituted the protein in giant liposomes amenable to patch clamp recording. The protein exhibited the expected electrophysiological properties in terms of kinetics, selectivity, and pharmacology. Negative pressure (suction) applied through the pipette had no effect on the channel, but positive pressure could completely and reversibly close the channel. Our interpretation of these data is that the intrinsic tension in the lipid bilayer is sufficient to maximally activate the channel, which can be closed upon modification of the tension. These results indicate that TREK-1 is directly sensitive to membrane tension.

scholarly journals Connecting the Dots between Mechanosensitive Channel Abundance, Osmotic Shock, and Survival at Single-Cell Resolution

2018 ◽  
Vol 200 (23) ◽  
Author(s):  
Griffin Chure ◽  
Heun Jin Lee ◽  
Akiko Rasmussen ◽  
Rob Phillips
Keyword(s):  
Cell Survival ◽  
Single Cell ◽  
Osmotic Shock ◽  
Single Cells ◽  
Mechanosensitive Channel ◽  
Membrane Tension ◽  
Wild Type ◽  
Content Type ◽  
E Coli ◽  
Structural Methods

ABSTRACTRapid changes in extracellular osmolarity are one of many insults microbial cells face on a daily basis. To protect against such shocks,Escherichia coliand other microbes express several types of transmembrane channels that open and close in response to changes in membrane tension. InE. coli, one of the most abundant channels is the mechanosensitive channel of large conductance (MscL). While this channel has been heavily characterized through structural methods, electrophysiology, and theoretical modeling, our understanding of its physiological role in preventing cell death by alleviating high membrane tension remains tenuous. In this work, we examine the contribution of MscL alone to cell survival after osmotic shock at single-cell resolution using quantitative fluorescence microscopy. We conducted these experiments in anE. colistrain which is lacking all mechanosensitive channel genes save for MscL, whose expression was tuned across 3 orders of magnitude through modifications of the Shine-Dalgarno sequence. While theoretical models suggest that only a few MscL channels would be needed to alleviate even large changes in osmotic pressure, we find that between 500 and 700 channels per cell are needed to convey upwards of 80% survival. This number agrees with the average MscL copy number measured in wild-typeE. colicells through proteomic studies and quantitative Western blotting. Furthermore, we observed zero survival events in cells with fewer than ∼100 channels per cell. This work opens new questions concerning the contribution of other mechanosensitive channels to survival, as well as regulation of their activity.IMPORTANCEMechanosensitive (MS) channels are transmembrane protein complexes which open and close in response to changes in membrane tension as a result of osmotic shock. Despite extensive biophysical characterization, the contribution of these channels to cell survival remains largely unknown. In this work, we used quantitative video microscopy to measure the abundance of a single species of MS channel in single cells, followed by their survival after a large osmotic shock. We observed total death of the population with fewer than ∼100 channels per cell and determined that approximately 500 to 700 channels were needed for 80% survival. The number of channels we found to confer nearly full survival is consistent with the counts of the numbers of channels in wild-type cells in several earlier studies. These results prompt further studies to dissect the contribution of other channel species to survival.

scholarly journals Fluorescent Ion Efflux Screening Assay for Determining Membrane-Active Peptides

2017 ◽  
Vol 70 (2) ◽  
pp. 220
Author(s):  
Neil M. O'Brien-Simpson ◽  
Wenyi Li ◽  
Namfon Pantarat ◽  
Mohammed Akhter Hossain ◽  
Frances Separovic ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Solid Phase ◽  
Bacterial Species ◽  
Membrane Integrity ◽  
Membrane Model ◽  
Bacterial Membrane ◽  
Membrane Composition ◽  
Screening Assay ◽  
Ion Efflux ◽  
Membrane Interactive

A major global health threat is the emergence of antibiotic-resistant microbes. Coupled with a lack of development of modified antibiotics, there is a need to develop new antimicrobial molecules and screening assays for them. In this study, we provide proof of concept that a large unilamellar vesicle (LUV) method used to study chloride ion efflux facilitated by ionophores and surfactant-like molecules that disrupt membrane integrity can be adapted to identify membrane-interactive antimicrobial peptides (AMPs) and to screen relative activity of AMPs. Lucigenin was encapsulated in LUVs in the presence of Cl– ion (NaCl), which quenches fluorescence, and then incubated with AMPs in 100 mM NaNO3 buffer. Upon AMP membrane interaction or disruption, the Cl– ion is exchanged with the NO3– ion, and the resultant lucigenin fluorescence is indicative of relative AMP activity. Seven AMPs were synthesized by solid-phase peptide chemistry and incubated with LUVs of different phospholipid compositions. Each AMP resulted in lucigenin fluorescence, which was dose dependent, and the relative fluorescence correlated with the minimum inhibitory concentration and minimum bactericidal concentration values for the corresponding peptide. Furthermore, using mammalian model phospholipid LUVs, lucigenin-induced fluorescence also correlated with the AMP cytotoxicity half-maximal inhibitory concentration values. The proline-rich AMP, Chex1-Arg20, which is non-lytic but interacts with the bacterial membrane resulted in lucigenin fluorescence of bacterial membrane model LUVs but not of mammalian membrane model LUVs. The fluorescent ion efflux assay developed here should have applicability for most AMPs and could be tailored to target particular bacterial species membrane composition, potentially leading to the identification of novel membrane-interactive AMPs. The rapid high-throughput method also allows for screening of relative AMP activity and toxicity before biological testing.

Sign in / Sign up

Export Citation Format

Share Document