scholarly journals Role of Peptide Hydrophobicity in the Mechanism of Action of α-Helical Antimicrobial Peptides

2006 ◽  
Vol 51 (4) ◽  
pp. 1398-1406 ◽  
Author(s):  
Yuxin Chen ◽  
Michael T. Guarnieri ◽  
Adriana I. Vasil ◽  
Michael L. Vasil ◽  
Colin T. Mant ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
High Performance ◽  
Reversed Phase ◽  
Aqueous Environments ◽  
Self Association ◽  
Peptide Helicity ◽  
Peptide Hydrophobicity

ABSTRACT In the present study, the 26-residue amphipathic α-helical antimicrobial peptide V13KL (Y. Chen et al., J. Biol. Chem. 2005, 280:12316-12329, 2005) was used as the framework to study the effects of peptide hydrophobicity on the mechanism of action of antimicrobial peptides. Hydrophobicity was systematically decreased or increased by replacing leucine residues with less hydrophobic alanine residues or replacing alanine residues with more hydrophobic leucine residues on the nonpolar face of the helix, respectively. Hydrophobicity of the nonpolar face of the amphipathic helix was demonstrated to correlate with peptide helicity (measured by circular dichroism spectroscopy) and self-associating ability (measured by reversed-phase high-performance liquid chromatography temperature profiling) in aqueous environments. Higher hydrophobicity was correlated with stronger hemolytic activity. In contrast, there was an optimum hydrophobicity window in which high antimicrobial activity could be obtained. Decreased or increased hydrophobicity beyond this window dramatically decreased antimicrobial activity. The decreased antimicrobial activity at high peptide hydrophobicity can be explained by the strong peptide self-association which prevents the peptide from passing through the cell wall in prokaryotic cells, whereas increased peptide self-association had no effect on peptide access to eukaryotic membranes.

The role of the temperature in reversed-phase high-performance liquid chromatography using pyrocarbon-containing adsorbents

1978 ◽  
Vol 167 ◽  
pp. 41-65 ◽  
Author(s):  
Henri Colin ◽  
José Carlos Diez-Masa ◽  
Georges Guiochon ◽  
Teresa Czjkowska ◽  
Iréna Miedziak
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Reversed Phase

scholarly journals BIOLOGICAL ACTIVITY OF ANTIMICROBIAL PEPTIDES FROM CHICKENS THROMBOCYTES

2016 ◽  
pp. 24-29
Author(s):  
M. V. Sycheva ◽  
A. S. Vasilchenko ◽  
E. A. Rogozhin ◽  
T. M. Pashkova ◽  
L. P. Popova ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
High Performance ◽  
Bactericidal Effect ◽  
Reverse Phase ◽  
Chromatography Method ◽  
E Coli ◽  
Liquid Chromatography Method ◽  
First Time ◽  
Peptide Fractions

Aim. Isolation and study ofbiological activity of antimicrobial peptides from chickens thrombocytes. Materials and methods. Peptides from chickens thrombocytes, obtained by reverse-phase high-performance liquid chromatography method with stepped and linear gradients of concentration increase of the organic solvent were used in the study. Their antimicrobial activity was determined by microtitration method in broth; mechanism of biological effect - by using fluorescent spectroscopy method with DNA-tropic dyes. Results. Individual fractions of peptides were isolated from chickens thrombocytes, that possess antimicrobial activity against Staphylococcus aureus P209 and Escherichia coli K12. A disruption of integrity of barrier structures of microorganisms under the effect of thrombocyte antimicrobial peptides and predominance of cells with damaged membrane in the population of E. coli was established. Conclusion. The data obtained on antimicrobial activity and mechanism of bactericidal effect of the peptide fractions from chickens thrombocytes isolated for the first time expand the understanding of functional properties of chickens thrombocytes and open a perspective for their further study with the aim of use as antimicrobial means.

scholarly journals Antimicrobial peptides from Capsicum chinense fruits: agronomic alternatives against phytopathogenic fungi

2020 ◽  
Vol 40 (8) ◽  
Author(s):  
Layrana de Azevedo dos Santos ◽  
Gabriel Bonan Taveira ◽  
Marciele Souza da Silva ◽  
Rodrigo da Silva Gebara ◽  
Lídia da Silva Pereira ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
High Performance ◽  
Protein Extraction ◽  
Phytopathogenic Fungi ◽  
Lipid Transfer ◽  
Capsicum Chinense ◽  
Microbial Inhibition ◽  
Specific Lipid ◽  
Strong Antimicrobial Activity

Abstract In recent years, the antimicrobial activity of peptides isolated from a wide variety of organs from plant species has been reported. However, a few studies have investigated the potential of antimicrobial peptides (AMPs) found in fruits, especially Capsicum chinense (pepper). The present study aimed to purify and characterize peptides from Capsicum chinense fruits and evaluate their inhibitory activities against different phytopathogenic fungi and also analyze the possible mechanisms of action involved in microbial inhibition. After fruit protein extraction and high-performance liquid chromatography (HPLC), different fractions were obtained, named F1 to F10. Peptides in the F4 and F5 fractions were sequenced and revealed similarity with the plant antimicrobial peptides like non-specific lipid transfer proteins and defensin-like peptide. The F4 and F5 fractions presented strong antimicrobial activity against the fungus Fusarium solani and Fusarium oxysporum, causing toxic effects on these fungi, leading to membrane permeabilization, endogenous reactive oxygen species increase, activation of metacaspase and loss of mitochondrial function.

scholarly journals Evaluating the Bioactivity of a Novel Broad-Spectrum Antimicrobial Peptide Brevinin-1GHa from the Frog Skin Secretion of Hylarana guentheri and Its Analogues

Toxins ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 413 ◽  
Author(s):  
Qi Chen ◽  
Peng Cheng ◽  
Chengbang Ma ◽  
Xinping Xi ◽  
Lei Wang ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptide ◽  
Broad Spectrum ◽  
Hemolytic Activity ◽  
High Performance ◽  
Disulfide Bridge ◽  
Reversed Phase ◽  
Central Position ◽  
Skin Secretion ◽  
Mass Spectral

Many antimicrobial peptides (AMPs) have been identified from the skin secretion of the frog Hylarana guentheri (H.guentheri), including Temporin, Brevinin-1, and Brevinin-2. In this study, an antimicrobial peptide named Brevinin-1GHa was identified for the first time by using ‘shotgun’ cloning. The primary structure was also confirmed through mass spectral analysis of the skin secretion purified by reversed-phase high-performance liquid chromatography (RP-HPLC). There was a Rana-box (CKISKKC) in the C-terminal of Brevinin-1GHa, which formed an intra-disulfide bridge. To detect the significance of Rana-box and reduce the hemolytic activity, we chemically synthesized Brevinin-1GHb (without Rana-box) and Brevinin-1GHc (Rana-box in central position). Brevinin-1GHa exhibited a strong and broad-spectrum antimicrobial activity against seven microorganisms, while Brevinin-1GHb only inhibited the growth of Staphylococcus aureus (S. aureus), which indicates Rana-box was necessary for the antimicrobial activity of Brevinin-1GHa. The results of Brevinin-1GHc suggested transferring Rana-box to the central position could reduce the hemolytic activity, but the antimicrobial activity also declined. Additionally, Brevinin-1GHa demonstrated the capability of permeating cell membrane and eliminating biofilm of S. aureus, Escherichia coli (E. coli), and Candida albicans (C. albicans). The discovery of this research may provide some novel insights into natural antimicrobial drug design.

scholarly journals Antimicrobial Peptides from Human Platelets

2002 ◽  
Vol 70 (12) ◽  
pp. 6524-6533 ◽  
Author(s):  
Yi-Quan Tang ◽  
Michael R. Yeaman ◽  
Michael E. Selsted
Keyword(s):  
Antimicrobial Peptides ◽  
High Performance ◽  
Antimicrobial Activities ◽  
Reversed Phase ◽  
Human Platelets ◽  
Platelet Factor ◽  
E Coli ◽  
Mediators Of Inflammation ◽  
Human Thrombin

ABSTRACT Platelets share structural and functional similarities with granulocytes known to participate in antimicrobial host defense. To evaluate the potential antimicrobial activities of platelet proteins, normal human platelets were stimulated with human thrombin in vitro. Components of the stimulated-platelet supernatants were purified to homogeneity by reversed-phase high-performance liquid chromatography. Purified peptides with inhibitory activity against Escherichia coli ML35 in an agar diffusion antimicrobial assay were characterized by mass spectrometry, amino acid analysis, and sequence determination. These analyses enabled the identification of seven thrombin-releasable antimicrobial peptides from human platelets: platelet factor 4 (PF-4), RANTES, connective tissue activating peptide 3 (CTAP-3), platelet basic protein, thymosin β-4 (Tβ-4), fibrinopeptide B (FP-B), and fibrinopeptide A (FP-A). With the exception of FP-A and FP-B, all peptides were also purified from acid extracts of nonstimulated platelets. The in vitro antimicrobial activities of the seven released peptides were further tested against bacteria (E. coli and Staphylococcus aureus) and fungi (Candida albicans and Cryptococcus neoformans). Each peptide exerted activity against at least two organisms. Generally, the peptides were more potent against bacteria than fungi, activity was greater at acidic pHs, and antimicrobial activities were dose dependent. Exceptions to these observations were observed with PF-4, which displayed a bimodal dose-response relationship in microbicidal assays, and Tβ-4, which had greater activity at alkaline pHs. At concentrations at which they were individually sublethal, PF-4 and CTAP-3 exerted synergistic microbicidal activity against E. coli. Collectively, these findings suggest a direct antimicrobial role for platelets as they are activated to release peptides in response to trauma or mediators of inflammation.

Identification of free and conjugated steroids, including cortisol and 17α,20β-dihydroxy-4-pregnen-3-one, in the milt of Pacific herring, Clupea harengus pallasi

1991 ◽  
Vol 69 (1) ◽  
pp. 104-110 ◽  
Author(s):  
A. P. Scott ◽  
Nancy M. Sherwood ◽  
A. V. M. Canario ◽  
Carol M. Warby
Keyword(s):  
High Performance ◽  
Potential Role ◽  
Reversed Phase ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Clupea Harengus Pallasi ◽  
Layer Chromatography ◽  
Free Steroid ◽  
Conjugated Steroids

Milt from Pacific herring (Clupea harengus pallasi) was extracted and purified on reversed-phase high-performance liquid chromatography. The fractions were radioimmunoassayed for the following free and conjugated steroids: cortisol; 17α,20β-dihydroxy-4-pregnen-3-one; 17α,20α-dihydroxy-4-pregnen-3-one; 17α,21-dihydroxy-4-pregnene-3,20-dione; 17α,20β,21-trihydroxy-4-pregnen-3-one; 17α-hydroxy-4-pregnene-3,20-dione; 3α,17α,21-trihydroxy-5β-pregnan-20-one; testosterone; 11-ketotestosterone. Fractions containing significant amounts of immunoreactive material were subjected to further purification on thin-layer chromatography. Substantial amounts of cortisol (271 ng∙g−1 of milt) and 17α,20β-dihydroxy-4-pregnen- 3-one (ca. 38 ng∙g−1 of milt) were found in the free fractions of one of the extracts. Substantial amounts of cortisol (229 ng∙g−1 of milt), 17α,20β-dihydroxy-4-pregnen-3-one (25.7 ng∙g−1 of milt), and 3a, 17α,21-trihydroxy-5β-pregnan- 20-one (13 ng∙g−1 of milt) were found in the conjugated fractions of both extracts. Levels of the other steroids (free and conjugated) ranged from undetectable (<0.1) to 5.9 ng∙g−1 of milt. The possible reasons for the differences in free steroid levels between the extracts, and the potential role of the steroids as pheromones, are discussed.

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