scholarly journals Development of a novel antimicrobial peptide AWRK6

2016 ◽  
Vol 11 (2) ◽  
pp. 460 ◽  
Author(s):  
Dusik  Kim ◽  
Zheng  Wang ◽  
Lili  Jin ◽  
Hanpin  Li ◽  
Junwei  Hwang ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Antimicrobial Activities ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Negative ◽  
Killing Rate ◽  
Physiological Conditions ◽  
Alkaline Environments ◽  
Improved Stability ◽  
Rana Dybowskii

<p class="Abstract">We have previously identified an antimicrobial peptide called dybowskin2-CDYa (Dy2) in the cutaneous secretion from the Chinese frog Rana dybowskii. In this study, we used Dy2 as a template to prepare some novel peptides with improved stability and hydrophobicity. The antimicrobial activities exerted by these peptides against Gram positive and Gram negative bacteria were evaluated by MIC and CFU assays under physiological conditions. One peptide, AWRK6, was 2-4 fold more potent than Dy2, and was toxic to most of the bacterial strains tested, exhibiting a faster killing rate.  AWRK6 was most potent in alkaline environments, and this was related to the more highly organized secondary structure of the peptide, as revealed by circular dichroism spectroscopy. Furthermore, AWRK6 was more resistant than Dy2 to degradation by trypsin. The improved properties of AWRK6 suggested that the peptide could potentially be further developed into an antibiotic.</p><p> </p>

scholarly journals “Clicking” an Ionic Liquid to a Potent Antimicrobial Peptide: On the Route towards Improved Stability

2020 ◽  
Vol 21 (17) ◽  
pp. 6174
Author(s):  
Ana Gomes ◽  
Lucinda J. Bessa ◽  
Patrícia Correia ◽  
Iva Fernandes ◽  
Ricardo Ferraz ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Peptide ◽  
Clinical Isolate ◽  
Bioactive Peptides ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Improved Stability

A covalent conjugate between an antibacterial ionic liquid and an antimicrobial peptide was produced via “click” chemistry, and found to retain the parent peptide’s activity against multidrug-resistant clinical isolates of Gram-negative bacteria, and antibiofilm action on a resistant clinical isolate of Klebsiella pneumoniae, while exhibiting much improved stability towards tyrosinase-mediated modifications. This unprecedented communication is a prelude for the promise held by ionic liquids -based approaches as tools to improve the action of bioactive peptides.

scholarly journals Synthesis and antimicrobial activity of some new N-(aryl-oxo-alkyl)-5-arylidene-thiazolidine-2,4-diones

2014 ◽  
Vol 79 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Anca Stana ◽  
Brînduşa Tiperciuc ◽  
Mihaela Duma ◽  
Adrian Pîrnău ◽  
Philippe Verité ◽  
...  
Keyword(s):  
Antimicrobial Activities ◽  
Fungal Strain ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Reference Drug ◽  
Gram Negative ◽  
E Coli ◽  
Inhibitory Activities

A series of new 5-(2,6-dichlorobenzylidene)thiazolidine-2,4-dione and 5-(4-methoxy-benzylidene)thiazolidine-2,4-dione derivatives (3a-h and 5a-h) were synthesized starting from 5-arylidene-thiazolidine-2,4-dione and ?-halo-ketones. The structural elucidation of the newly synthesized compounds was based on elemental analysis and spectroscopic data (MS, 1H-NMR, 13C-NMR). The synthesized compounds were screened for their antimicrobial activities against several pathogenic strains of Gram-positive and Gram-negative bacteria and one fungal strain (Candida albicans), assessed in vitro as growth inhibition diameters. Some of them displayed better inhibitory activities than that of the reference drug against the Gram-positive S. aureus, B. cereus, L. monocytogenes bacterial strains, and showed good antifungal activity against C. albicans, while the antibacterial activity against Gram-negative E. coli and S. typhimurium bacterial strains was moderate.

Antimicrobial Activity of Iron-Halide Complexes Against Gram-Positive and Gram-Negative Bacteria

2020 ◽  
Author(s):  
Nusrat Abedin ◽  
Abdullah Hamed A Alshehri ◽  
Ali M A Almughrbi ◽  
Olivia Moore ◽  
Sheikh Alyza ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Resistance ◽  
Extracellular Dna ◽  
Antibiofilm Activity ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial Substances ◽  
Mammalian Cell Lines

Antimicrobial resistance (AMR) has become one of the more serious threats to the global health. The emergence of bacteria resistant to antimicrobial substances decreases the potencies of current antibiotics. Consequently, there is an urgent and growing need for the developing of new classes of antibiotics. Three prepared novel iron complexes have a broad-spectrum antimicrobial activity with minimum bactericidal concentration (MBC) values ranging from 3.5 to 10 mM and 3.5 to 40 mM against Gram-positive and Gram-negative bacteria with antimicrobial resistance phenotype, respectively. Time-kill studies and quantification of the extracellular DNA confirmed the bacteriolytic mode of action of the iron-halide compounds. Additionally, the novel complexes showed significant antibiofilm activity against the tested pathogenic bacterial strains at concentrations lower than the MBC. The cytotoxic effect of the complexes on different mammalian cell lines show sub-cytotoxic values at concentrations lower than the minimum bactericidal concentrations.

scholarly journals Antimicrobial Activities of Mefloquine and a Series of Related Compounds

2000 ◽  
Vol 44 (4) ◽  
pp. 848-852 ◽  
Author(s):  
C. M. Kunin ◽  
W. Y. Ellis
Keyword(s):  
Staphylococcus Epidermidis ◽  
Antimicrobial Activities ◽  
Walter Reed Army Institute ◽  
Gram Negative Bacteria ◽  
Antimicrobial Drugs ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Related Compounds

ABSTRACT Mefloquine was found to have bactericidal activity against methicillin- and fluoroquinolone-susceptible and -resistant strains ofStaphylococcus aureus and Staphylococcus epidermidis and gentamicin- and vancomycin-resistant strains ofEnterococcus faecalis and Enterococcus faecium. The MICs were 16 μg/ml, and the minimal bactericidal concentrations (MBCs) were 16 to 32 μg/ml. These concentrations cannot be achieved in serum. Mefloquine was active at a more achievable concentration against penicillin-susceptible and -resistant Streptococcus pneumoniae, with MICs of 0.2 to 1.5 μg/ml. Mefloquine was not active against gram-negative bacteria and yeasts. In an attempt to find more active derivatives, 400 mefloquine-related compounds were selected from the chemical inventory of The Walter Reed Army Institute of Research. We identified a series of compounds containing a piperidine methanol group attached to pyridine, quinoline, and benzylquinoline ring systems. These had activities similar to that of mefloquine against S. pneumoniae but were far more active against other gram-positive bacteria (MICs for staphylococci, 0.8 to 6.3 μg/ml). They had activities similar to that of amphotericin B againstCandida spp. and Cryptococcus neoformans. Combinations of the compounds with gentamicin and vancomycin were additive against staphylococci and pneumococci. The MIC and MBC of gentamicin were decreased by four- to eightfold when this drug was combined with limiting dilutions of the compounds. There was no antagonism with other antimicrobial drugs. The compounds were rapidly bactericidal. They appear to act by disrupting cell membranes. Combinations of the compounds with aminoglycoside antibiotics may have potential for therapeutic use.

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 Improved Derivatives of Bactenecin, a Cyclic Dodecameric Antimicrobial Cationic Peptide

1999 ◽  
Vol 43 (5) ◽  
pp. 1274-1276 ◽  
Author(s):  
Manhong Wu ◽  
Robert E. W. Hancock
Keyword(s):  
Amino Acid ◽  
Antimicrobial Peptide ◽  
Tryptophan Residue ◽  
Gram Negative Bacteria ◽  
Cationic Peptide ◽  
Gram Positive ◽  
Antimicrobial Spectrum ◽  
Gram Negative ◽  
Derivatives Of

ABSTRACT Both linear and cyclic derivatives of the cyclic 12-amino-acid antimicrobial peptide bactenecin were designed based on optimization of amphipathicity and charge location. In general, increasing the number of positive charges at the N and C termini and adding an extra tryptophan residue in the loop not only increased the activities against both gram-positive and gram-negative bacteria but also broadened the antimicrobial spectrum.

scholarly journals Ultrasonic Irradiation: Synthesis, Characterization, and Preliminary Antimicrobial Activity of Novel Series of 4,6-Disubstituted-1,3,5-triazine Containing Hydrazone Derivatives

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hessa H. Al-Rasheed ◽  
Monirah Al Alshaikh ◽  
Jamal M. Khaled ◽  
Naiyf S. Alharbi ◽  
Ayman El-Faham
Keyword(s):  
Antimicrobial Activity ◽  
Ultrasonic Irradiation ◽  
New Products ◽  
Conventional Heating ◽  
Pyridine Derivative ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial And Antifungal Activities

Novel series of 4,6-disubstituted-1,3,5-triazines containing hydrazone derivatives were synthesized employing ultrasonic irradiation and conventional heating. The ultrasonication gave the target products in higher yields and purity in shorter reaction time compared with the conventional method. IR, NMR (H 1 and C 13), elemental analysis, and LC-MS confirmed the structures of the new products. The antimicrobial and antifungal activities were evaluated for all the prepared compounds against some selected Gram-positive and Gram-negative bacterial strains. The results showed that only two compounds 7i (pyridine derivative) and 7k (4-chlorobenzaldehyde derivative) displayed biological activity against some Gram-positive and Gram-negative bacteria, while the rest of the tested compounds did not display any antifungal activity.

ANTIMICROBIAL ACTIVITY OF A MONOALKYL BENZENE SULPHONATE COMPLEX

1962 ◽  
Vol 8 (5) ◽  
pp. 621-628 ◽  
Author(s):  
W. A. Taber ◽  
B. B. Wiley
Keyword(s):  
Active Component ◽  
Fusarium Species ◽  
Antimicrobial Activities ◽  
Gram Negative Bacteria ◽  
Fusarium Spp ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Household Detergent ◽  
Fungi Imperfecti

The antimicrobial activities of a branched, monoalkyl benzene sulphonate complex (ABS), the active component of a commercial liquid household detergent, and of the detergent have been investigated. Cultures of dermatophytes, Candida albicans, saprophytic phycomycetes, ascomycetes, fungi imperfecti, Gram-positive and Gram-negative bacteria were tested. Only the Fusarium species and the Gram-negative bacteria were not inhibited by a concentration of 0.1 ml of the detergent/50 ml medium. Microgram quantities of ABS inhibited the Gram-positive bacteria and the fungi except Fusarium spp. ABS was lethal in microgram quantities, the effect being detectable within 30 minutes. Inhibition of exogenous respiration of glucose by C. albicans began upon contact and was complete within 50 minutes. A linear and biodegradable ABS was more active than the branched form against C. albicans.

scholarly journals Interactions of an antimicrobial peptide, magainin 2, with outer and inner membranes of Gram-negative bacteria

1997 ◽  
Vol 1327 (1) ◽  
pp. 119-130 ◽  
Author(s):  
Katsumi Matsuzaki ◽  
Ken-ichi Sugishita ◽  
Mitsunori Harada ◽  
Nobutaka Fujii ◽  
Koichiro Miyajima
Keyword(s):  
Antimicrobial Peptide ◽  
Gram Negative Bacteria ◽  
Gram Negative

Synergistic Effects of Essential Oils of Ammoides verticillata and Satureja candidissima Against Many Pathogenic Microorganisms

2020 ◽  
Vol 18 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Fatima Benyoucef ◽  
Mohammed El Amine Dib ◽  
Boufeldja Tabti ◽  
Arrar Zoheir ◽  
Jean Costa ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Synergistic Effects ◽  
Lactobacillus Rhamnosus ◽  
Salmonella Typhi ◽  
Antimicrobial Activities ◽  
Bacterial Strains ◽  
Gram Negative ◽  
Ammoides Verticillata

Background: Antibiotic resistance is today one of the most serious threats to global health, food security and development. Due to the growing number of infections, treatment becomes more difficult, if not impossible, because of the loss of antibiotic efficacy. Objective: In the present investigation, the chemical composition of essential oils of Ammoides verticillata and Satureja candidissima and their synergistic effects on antimicrobial activities were investigated. Methods: The chemical composition of the essential oil was analyzed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectroscopy (GC/MS). The antimicrobial activity of the essential oils was investigated using dilution-agar method against nine bacterial strains three Gram-negative Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Salmonella typhi (ATCC 14028), and six Gram-positive: Staphylococcus aureus (ATCC 43300,) Clostridium sporogenes (ATCC 19404), Bacillus subtilis (ATCC 6633), Enterococcus faecalis (ATCC 7314), Lactobacillus rhamnosus (ATCC 53103) and Bacillus cereus (ATCC 14579). Results: The essential oil of A. verticillata was characterized principally by carvacrol (44,3%), Limonene (19,3%) and p-cymene (19,2%). The constituents identified of S. candidissima essential oil were principally oxygenated monoterpenes represented by pulegone (70,4%). The essential oil of A. verticillata had a good antimicrobial activity against four bacterial strains (Escherichia coli, Salmonella typhi, Lactobacillus rhamnosus and Bacillus cereus) with MIC and MBC values between 0.2-0.4 µl/ml and 0.2-6.2 µl/ml, respectively. While, S. candidissima essential oil had moderate antimicrobial activities against all strains with MIC and MBC values between 1.5-6.2 µl/ml and 6.2-12.5 µl/ml, respectively. The results of antimicrobial activity of essential oils blend presented higher antimicrobial activity against all tested bacteria with MIC and MBC values between 0.3-1.5 µl/ml and 0.4-6.2 µl/ml, respectively. Conclusion: The essential oils blend presented high antimicrobial activity compared to virgin oils. This activity can be due to the association of active compounds such as carvacrol and pulegone. These findings provide a new source of drugs that may help in therapy to lead to the development of a new treatment based on a combination of these essential oils against gram-negative and gram-positive bacteria that continue to pose a threat to public health.

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