C-Terminal Modifications Broaden Activity of the Proline-Rich Antimicrobial Peptide, Chex1-Arg20

2015 ◽  
Vol 68 (9) ◽  
pp. 1373 ◽  
Author(s):  
Wenyi Li ◽  
Julien Tailhades ◽  
M. Akhter Hossain ◽  
Neil M. O'Brien-Simpson ◽  
Eric C. Reynolds ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antimicrobial Peptide ◽  
Peptide Synthesis ◽  
Mammalian Cells ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Chemical Strategies

A series of N- and C-terminal modifications of the monomeric proline-rich antimicrobial peptide, Chex1-Arg20, was obtained via different chemical strategies using Fmoc/tBu solid-phase peptide synthesis in order to study their effects on a panel of Gram-negative bacteria. In particular, C-terminal modifications with hydrazide or alcohol functions extended their antibacterial activity from E. coli and K. pneumoniae to other Gram-negative species, A. baumannii and P. aeruginosa. Furthermore, these analogues did not show cytotoxicity towards mammalian cells. Hence, such modifications may aid in the development of more potent proline-rich antimicrobial peptides with a greater spectrum of activity against Gram-negative bacteria than the parent peptide.

scholarly journals NonToxic Silver/Poly-1-Vinyl-1,2,4-Triazole Nanocomposite Materials with Antibacterial Activity

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1477 ◽  
Author(s):  
Irina A. Shurygina ◽  
Galina F. Prozorova ◽  
Irina S. Trukhan ◽  
Svetlana A. Korzhova ◽  
Tatiana V. Fadeeva ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Mammalian Cells ◽  
Antimicrobial Properties ◽  
Fibroblast Cell ◽  
Nanocomposite Materials ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Fibroblast Cell Culture

Novel silver/poly-1-vinyl-1,2,4-triazole nanocomposite materials—possessing antimicrobial activity against Gram-positive and Gram-negative bacteria—have been synthesized and characterized in the solid state and aqueous solution by complex of modern physical-chemical and biologic methods. TEM-monitoring has revealed the main stages of microbial cell (E. coli) destruction by novel nanocomposite. The concept of direct polarized destruction of microbes by nanosilver proposed by the authors allows the relationship between physicochemical and antimicrobial properties of novel nanocomposites. At the same time, it was shown that the nanocomposite was nontoxic to the fibroblast cell culture. Thus, the synthesized nanocomposite combining antibacterial activity against Gram-positive and Gram-negative bacteria as well as the absence of toxic effects on mammalian cells is a promising material for the development of catheters, coatings for medical devices.

Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

2020 ◽  
Vol 16 (4) ◽  
pp. 481-488
Author(s):  
Heli Sanghvi ◽  
Satyendra Mishra
Keyword(s):  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Pyrazole Derivatives ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Curcumin Derivatives ◽  
Structure Activity ◽  
Electron Donating Groups ◽  
Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

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 Interaction of Antimicrobial Peptide Temporin L with Lipopolysaccharide In Vitro and in Experimental Rat Models of Septic Shock Caused by Gram-Negative Bacteria

2006 ◽  
Vol 50 (7) ◽  
pp. 2478-2486 ◽  
Author(s):  
Andrea Giacometti ◽  
Oscar Cirioni ◽  
Roberto Ghiselli ◽  
Federico Mocchegiani ◽  
Fiorenza Orlando ◽  
...  
Keyword(s):  
Septic Shock ◽  
Antimicrobial Peptide ◽  
Gram Negative Bacteria ◽  
Amphibian Skin ◽  
Necrosis Factor Alpha ◽  
Gram Negative ◽  
Rat Models ◽  
E Coli ◽  
Tnf Α

ABSTRACT Sepsis remains a major cause of morbidity and mortality in hospitalized patients, despite intense efforts to improve survival. The primary lead for septic shock results from activation of host effector cells by endotoxin, the lipopolysaccharide (LPS) associated with cell membranes of gram-negative bacteria. For these reasons, the quest for compounds with antiendotoxin properties is actively pursued. We investigated the efficacy of the amphibian skin antimicrobial peptide temporin L in binding Escherichia coli LPS in vitro and counteracting its effects in vivo. Temporin L strongly bound to purified E. coli LPS and lipid A in vitro, as proven by fluorescent displacement assay, and readily penetrated into E. coli LPS monolayers. Furthermore, the killing activity of temporin L against E. coli was progressively inhibited by increasing concentrations of LPS added to the medium, further confirming the peptide's affinity for endotoxin. Antimicrobial assays showed that temporin L interacted synergistically with the clinically used β-lactam antibiotics piperacillin and imipenem. Therefore, we characterized the activity of temporin L when combined with imipenem and piperacillin in the prevention of lethality in two rat models of septic shock, measuring bacterial growth in blood and intra-abdominal fluid, endotoxin and tumor necrosis factor alpha (TNF-α) concentrations in plasma, and lethality. With respect to controls and single-drug treatments, the simultaneous administration of temporin L and β-lactams produced the highest antimicrobial activities and the strongest reduction in plasma endotoxin and TNF-α levels, resulting in the highest survival rates.

scholarly journals Water-dispersible glycosylated poly(2,5′-thienylene)porphyrin-based nanoparticles for antibacterial photodynamic therapy

2019 ◽  
Vol 18 (5) ◽  
pp. 1147-1155 ◽  
Author(s):  
Rehan Khan ◽  
Melis Özkan ◽  
Aisan Khaligh ◽  
Dönüs Tuncel
Keyword(s):  
Antibacterial Activity ◽  
Photodynamic Therapy ◽  
Singlet Oxygen ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Water Dispersible ◽  
Gram Positive Bacteria ◽  
High Yields

Water-dispersible glycosylated poly(2,5′-thienylene)porphyrin-based nanoparticles have the ability to generate singlet oxygen in high yields and exhibit light-triggered antibacterial activity against Gram negative bacteria, E. coli as well as Gram positive bacteria, B. subtilis.

Synthesis, Characterization, and Antibacterial Evaluation of Curcumin-Sulfanilamide Compound

2020 ◽  
Vol 840 ◽  
pp. 265-269
Author(s):  
Nurjanah Nurjanah ◽  
Endang Saepudin
Keyword(s):  
Antibacterial Activity ◽  
Functional Group ◽  
Biological Activities ◽  
Curcuma Longa ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Ftir Spectrophotometry

Curcumin, a diarylheptanoids compound which isolated primary from Curcuma longa, exhibits a variety of exciting biological activities, including as an antibacterial agent. In the present study, a sulfanilamide-contained curcumin compound was synthesized and characterized to investigate the antibacterial activity against gram-positive bacteria S. aureus, B. subtilis and gram-negative bacteria E. coli. The characterization of the synthesized compound was determined by analysing peak absorbance, functional group, and molecular weight using mass spectroscopy, UV/Vis and FTIR spectrophotometry. Curcumin-sulfanilamide compound exhibited the best antibacterial activity against gram-negative bacteria compared to curcumin and the curcumin-derived compound containing isoxazole with inhibitory zone of 11 mm.

scholarly journals Synthesis and Antibacterial Activity of Chalcones and Pyrimidine-2-ones

2005 ◽  
Vol 2 (2) ◽  
pp. 109-112
Author(s):  
A. K. Parekh ◽  
K. K. Desai
Keyword(s):  
Antibacterial Activity ◽  
Spectral Data ◽  
Elemental Analysis ◽  
Aromatic Aldehydes ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
H Nmr

Some new chalcones have been prepared by Claisen-schmidt condensation of ketone and different aromatic aldehydes. These chalcones on condensation with urea in presence of acid gave Pyrimidine-2-ones. The synthesized compounds have been characterized by elemental analysis, IR and1H NMR spectral data. They have been screened for their antibacterial activity against Gram positive bacteria B. subtillis & S. aureus and Gram negative bacteria E. coli & S. typhi.

scholarly journals Antibacterial Activityof Aqueous And Ethanolic Leaf Extracts Of Vernonia Amygdalina On Selected Species Of Gram Positive And Gram Negative Bacteria

2013 ◽  
Vol 2 (1) ◽  
pp. 147-152 ◽  
Author(s):  
AM Bukar ◽  
MA Isa ◽  
HS Bello ◽  
AS Abdullahi
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Drug ◽  
Gram Negative Bacteria ◽  
Phytochemical Screening ◽  
Vernonia Amygdalina ◽  
Leaf Extracts ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Pseudomonas Species

The phytochemical screening and antibacterial activity of ethanolic and Methanolic leaves extract of Vernonia amygdalina against five clinical isolates (Staphylococcus aureus, E. coli, Pseudomonas species, Salmonella species and Proteus species) was determined using standard method of analysis. The results of the antibacterial activity of ethanol, methanol and aqueous extract of leaves of V. amygdalina have diameters ranging between 0.4 to 10mm. The plant extracts from the plants had profound activities against gram-positive than gram negative bacteria. From the above studies, it has clearly indicated that V. amygdalina extract may represent new sources of antibacterial drug, if the phytoactive components are purified and proper dosage are determined for administration. International Journal of Environment, Volume-2, Issue-1, Sep-Nov 2013, Pages 147-152 DOI: http://dx.doi.org/10.3126/ije.v2i1.9217

PEMANFAATAN SARANG SEMUT (Myrmecodia pendens) ASAL KALIMANTAN SELATAN SEBAGAI ANTIBAKTERI

2010 ◽  
Vol 2 (2) ◽  
pp. 31
Author(s):  
Farida Crisnaningtyas
Keyword(s):  
Antibacterial Activity ◽  
Ethanol Extract ◽  
Proximate Analysis ◽  
Gram Negative Bacteria ◽  
Bacillus Sp ◽  
Clear Zone ◽  
Gram Negative ◽  
E Coli ◽  
Ant Nests ◽  
Ant Nest

The use of ant nests (Myrmecodia pendens) native of Borneo as an antibacterial. The aim of this research is to make the crude drug  from the ant nest, simply extracting, condensing and test the ability of anti-bacterial properties of ant nests. This study covers the development of these extracts, proximate analysis, and test the antibacterial activity of plant-ant nest. Parameters measured were the growth of antibacterial activity against Salmonella sp., E. coli and Bacillus sp. showed by inhibition (clear zone). The results showed that plant-ant nests have antibacterial power. Ethanol extract of the ant nests provide a better inhibition compared with water extraction ant nests. Antibacterial activity of the ant nest extracts can be applied both in gram- positive and gram-negative bacteria. Key wood : ant nest, antibacterial,  inhibition capability

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