Anticandidal activity of synthetic peptides: Mechanism of action revealed by scanning electron and fluorescence microscopies and synergism effect with nystatin

2020 ◽  
Vol 26 (6) ◽  
Author(s):  
Patrícia G. Lima ◽  
Pedro F.N. Souza ◽  
Cleverson D.T. Freitas ◽  
Jose T.A. Oliveira ◽  
Lucas P. Dias ◽  
...  
Keyword(s):  
Mechanism Of Action ◽  
Synthetic Peptides ◽  
Anticandidal Activity ◽  
Scanning Electron ◽  
Synergism Effect

scholarly journals Pathogenicity of Aspergillus westerdijkiae to females and oothecae of Periplaneta Americana

2015 ◽  
Vol 46 (1) ◽  
pp. 20-25 ◽  
Author(s):  
Mariah Valente Baggio ◽  
Marcelo da Costa Ferreira ◽  
Antonio Carlos Monteiro ◽  
Walter Maldonado Junior ◽  
Manoel Victor Franco Lemos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanism Of Action ◽  
Entomopathogenic Fungi ◽  
Periplaneta Americana ◽  
Selective Pressure ◽  
Aspergillus Westerdijkiae ◽  
Scanning Electron ◽  
Methods Of Control

ABSTRACT: Cockroach control is performed by the application of chemical insecticides which exert high selective pressure on populations and introduces synthetic substances in the environment, motivating the search for other methods of control such as entomopathogenic fungi. The objectives of this study were to investigate the pathogenicity of the JAB 42 Aspergillus westerdijkiae to females and oothecae of Periplaneta americana and to demonstrate its mechanism of action on oothecae. Suspensions containing 106 to 108 conidia/ml were used to infect females and oothecae. Mortality and other variables such as scanning electron microscopy were used to demonstrate the mechanism of action of the fungus. The isolated JAB 42 A. westerdijkiae is pathogenic to oothecae of P. americana, with low capacity to kill females. Adhesion, germination, penetration and extrusion of the fungus on the cockroach oothecae were observed.

Anticandidal activity of Inula helenium root essential oil: Synergistic potential, anti-virulence efficacy and mechanism of action

2020 ◽  
Vol 149 ◽  
pp. 112373
Author(s):  
Zorica Stojanović-Radić ◽  
Marina Dimitrijević ◽  
Marija Genčić ◽  
Milica Pejčić ◽  
Niko Radulović
Keyword(s):  
Essential Oil ◽  
Mechanism Of Action ◽  
Inula Helenium ◽  
Anticandidal Activity ◽  
Root Essential Oil

scholarly journals Candidacidal Activities of Human Lactoferrin Peptides Derived from the N Terminus

2000 ◽  
Vol 44 (12) ◽  
pp. 3257-3263 ◽  
Author(s):  
Antonella Lupetti ◽  
Akke Paulusma-Annema ◽  
Mick M. Welling ◽  
Sonia Senesi ◽  
Jaap T. van Dissel ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mechanism Of Action ◽  
Propidium Iodide ◽  
Synthetic Peptides ◽  
Antifungal Agents ◽  
Human Lactoferrin ◽  
N Terminus ◽  
Fluconazole Resistant ◽  
Dose Dependent ◽  
Sufficient Stimulus

ABSTRACT In light of the need for new antifungal agents, the candidacidal activities of human lactoferrin (hLF) and synthetic peptides representing the first, hLF(1-11), and second, hLF(21-31), cationic domains of its N terminus were compared. The results revealed that hLF(1-11) was more effective in killing fluconazole-resistantCandida albicans than hLF(21-31) and much more effective than lactoferrin, as determined microbiologically and by propidium iodide (PI) staining. By using hLF(1-11) and various derivatives, it was found that the second and third residues of the N terminus of hLF(1-11) were critical for its candidacidal activity. Detailed investigation to elucidate the mechanism of action of hLF(1-11) revealed a dose-dependent release of ATP by Candida upon exposure to hLF(1-11). Our observations that sodium azide reduced the PI uptake and candidacidal activity of hLF(1-11) and that, upon exposure to hLF(1-11), the fluorescent dye rhodamine 123 first accumulated inside the mitochondria and later was released into the cytoplasm indicate that the peptide triggers the energized mitochondrion. Furthermore, oxidized ATP, which interferes with the interaction of ATP with its extracellular receptors, blocked the candidacidal action of hLF(1-11), as measured microbiologically and by PI staining. Addition of ATP (or analogues) was not a sufficient stimulus to kill C. albicans or to act synergistically with suboptimal concentrations of the peptide. The main conclusions are that the first two arginines at the N terminus of hLF are critical in the candidacidal activity of hLF(1-11) and that extracellular ATP is essential but not sufficient for the peptide to exert its candidacidal activity.

Comparative antimicrobial activity and mechanism of action of bovine lactoferricin-derived synthetic peptides

BioMetals ◽  
2011 ◽  
Vol 24 (6) ◽  
pp. 1069-1078 ◽  
Author(s):  
Yifan Liu ◽  
Feifei Han ◽  
Yonggang Xie ◽  
Yizhen Wang
Keyword(s):  
Antimicrobial Activity ◽  
Mechanism Of Action ◽  
Synthetic Peptides ◽  
Bovine Lactoferricin

Antimicrobial Mechanism and Activity of Dodecyl Rosmarinate against Staphylococcus carnosus LTH1502 as Influenced by Addition of Salt and Change in pH

2014 ◽  
Vol 77 (3) ◽  
pp. 444-452 ◽  
Author(s):  
SARISA SURIYARAK ◽  
MONIKA GIBIS ◽  
HERBERT SCHMIDT ◽  
PIERRE VILLENEUVE ◽  
JOCHEN WEISS
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanism Of Action ◽  
Morphological Changes ◽  
Carbon Chain ◽  
Cell Number ◽  
Carbon Chain Length ◽  
Staphylococcus Carnosus ◽  
Microscopy Images ◽  
Scanning Electron

Antimicrobial activity and mechanism of action of rosmarinic acid (RA) and dodecyl rosmarinate (RE12) against Staphylococcus carnosus LTH1502 were studied as a function of pH (5.8 to 7.2) and in the presence of salts (KCl and MgCl2, 0 to 500 mM). Microbial cultures were exposed to unesterified RA and to esterified RE12, and cell number was determined by plate counting. Cells exposed to RA and RE12 at the minimum bactericidal concentration (200 and 0.05 mM, respectively) were examined using scanning electron microscopy to observe potential morphological changes. Activity of RA was found to be strongly dependent on pH, salt type, and concentration, whereas RE12 led to the compound's activity becoming independent of pH, salt concentration, and type. Scanning electron microscopy images showed that morphology of cells treated with RE12 after incubation of 1 h was irrevocably altered. Our results suggest that esterification (i) altered the mechanism of action by increasing the compound's affinity for cell membranes and (ii) decreased the compound's susceptibility to changes in environmental conditions that alter its charge. Highly specific changes in structure-activity relationships can be observed when esterifying a naturally active phenol such as RA with an alkyl chain that has a carbon chain length of 12.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

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