Results 1 - 10
of
25
Immunomodulatory activity of small host defense peptides
- Antimicrob. Agents Chemother
, 2005
"... These include: This article cites 40 articles, 24 of which can be accessed free at: ..."
Abstract
-
Cited by 19 (6 self)
- Add to MetaCart
(Show Context)
These include: This article cites 40 articles, 24 of which can be accessed free at:
Psoriatic scales: a promising source for the isolation of human skin-derived antimicrobial proteins
- Journal of Leukocyte Biology
, 2005
"... Abstract: Patients with psoriasis, a chronic, hyperproliferative and noninfectious skin disease, suffer surprisingly fewer cutaneous infections than would be expected. This observation led us to the hypothesis that a local “chemical shield ” in the form of antimicrobial proteins provides psoriatic s ..."
Abstract
-
Cited by 11 (0 self)
- Add to MetaCart
(Show Context)
Abstract: Patients with psoriasis, a chronic, hyperproliferative and noninfectious skin disease, suffer surprisingly fewer cutaneous infections than would be expected. This observation led us to the hypothesis that a local “chemical shield ” in the form of antimicrobial proteins provides psoriatic skin with resistance against infection. We subsequently began a systematic analysis of in vitro antimicrobially active proteins in psoriaticscale extracts. A biochemical approach with rigorous purification and characterization combined with antimicrobial testing identified a number of mostly new human antibiotic peptides and proteins. In this review, we will focus on the most prominent antimicrobial proteins in psoriaticscale extracts, which we identified as the S100protein psoriasin, human �-defensin 2 (hBD-2), RNase 7, lysozyme, and human neutrophil defensin 1–3. Apart from these cutaneous, antimicrobial proteins, only a few others, including hBD-3, have been characterized. A great number of minor antimicrobial proteins await further
Synergy with rifampin and kanamycin enhances potency, kill kinetics, and selectively of de novodesigned antimicrobial peptides
- Antimicrob. Agents Chemother
, 2010
"... By choosing membranes as targets of action, antibacterial peptides offer the promise of providing antibiotics to which bacteria would not become resistant. However, there is a need to increase their potency against bacteria along with achieving a reduction in toxicity to host cells. Here, we report ..."
Abstract
-
Cited by 2 (0 self)
- Add to MetaCart
(Show Context)
By choosing membranes as targets of action, antibacterial peptides offer the promise of providing antibiotics to which bacteria would not become resistant. However, there is a need to increase their potency against bacteria along with achieving a reduction in toxicity to host cells. Here, we report that three de novo-designed antibacterial peptides (Fm, Fmscr, and Ud) with poor to moderate antibacterial potencies and kill kinetics improved significantly in all of these aspects when synergized with rifampin and kanamycin against Escherichia coli. (Fm and Fmscr [a scrambled-sequence version of Fm] are isomeric, monomeric decapeptides containing the nonproteinogenic amino acid ,-didehydrophenylalanine [F] in their sequences. Ud is a lysine-branched dimeric peptide containing the helicogenic amino acid -aminoisobutyric acid [Aib].) In synergy with rifampin, the MIC of Fmscr showed a 34-fold decrease (67.9 g/ml alone, compared to 2 g/ml in combination). A 20-fold improvement in the minimum bactericidal concentration of Ud was observed when the peptide was used in combination with rifampin (369.9 g/ml alone, compared to 18.5 g/ml in combina-tion). Synergy with kanamycin resulted in an enhancement in kill kinetics for Fmscr (no killing until 60 min for Fmscr alone, versus 50 % and 90 % killing within 20 min and 60 min, respectively, in combination with kanamycin). Combination of the dendrimeric peptide Fq (a K-K2 dendrimer for which the sequence of Fm constitutes each of the four branches) (MIC, 21.3 g/ml) with kanamycin (MIC, 2.1 g/ml) not only lowered
Factors affecting the antimicrobial activity of ovine-derived cathelicidins against E. coli 0157:H7
, 2004
"... Antimicrobial peptides extracted from ovine neutrophils have potential to be high-value by-products of the lamb industry as, for example, a biopreservative for chilled lamb products. This work was carried out to determine the conditions in which ovine peptides are most effective and to assist in pro ..."
Abstract
-
Cited by 1 (0 self)
- Add to MetaCart
(Show Context)
Antimicrobial peptides extracted from ovine neutrophils have potential to be high-value by-products of the lamb industry as, for example, a biopreservative for chilled lamb products. This work was carried out to determine the conditions in which ovine peptides are most effective and to assist in product development. The activities of three synthetic ovine-derived antimicrobial peptides tested were not significantly affected by pH or temperature. However, they exhibited decreased activity at high ionic strengths and in the presence of divalent cations. The three peptides worked better in combination than individually.
1 The human host defence peptide LL-37 prevents bacterial biofilm formation
"... Summary The ability to form biofilms is a critical factor in chronic infections by Pseudomonas aeruginosa and has made this bacterium a model organism with respect to biofilm formation. This study describes a new, previously unrecognized role for the human cationic host defence peptide LL-37. In add ..."
Abstract
- Add to MetaCart
(Show Context)
Summary The ability to form biofilms is a critical factor in chronic infections by Pseudomonas aeruginosa and has made this bacterium a model organism with respect to biofilm formation. This study describes a new, previously unrecognized role for the human cationic host defence peptide LL-37. In addition to its key role in modulating the innate immune response and weak antimicrobial activity, LL-37 potently inhibited the formation of bacterial biofilms in vitro. This occurred at very low and physiologically meaningful concentrations of 0.5 µg/ml, far below those required to kill or inhibit growth (MIC = 64 µg/ml). LL-37 also impacted on existing, pregrown P. aeruginosa biofilms. Similar results were obtained using the bovine neutrophil peptide indolicidin, but no inhibitory effect on biofilm formation was detected using sub-inhibitory concentrations of the mouse peptide CRAMP, which shares 67 % identity with LL-37, polymyxin B, or the bovine bactenecin homolog Bac2A. Using microarrays and follow up studies we were able to demonstrate that LL-37 impacted on biofilm formation by decreasing attachment of bacterial cells, stimulating twitching motility and influencing two major quorum sensing systems (Las and Rhl), leading to the down-regulation of genes essential for biofilm development.
3 4 5 6 7 8
"... Synergy with rifampicin and kanamycin enhances potency, kill kinetics and selectivity of de novo designed antimicrobial peptides 1 2 ..."
Abstract
- Add to MetaCart
(Show Context)
Synergy with rifampicin and kanamycin enhances potency, kill kinetics and selectivity of de novo designed antimicrobial peptides 1 2
1 MODE OF ACTION STUDIES ON SYNTHETIC ANTIMICROBIAL PEPTIDES MASTER THESIS IN MEDICAL BIOLOGY AND MOLECULAR BIOLOGY
, 2013
"... Increasing prevalence of bacteria that carries resistance towards conventional antibiotics has prompted the investigation into new compounds for bacterial intervention to ensure efficient infection control in the future. One group of potential lead structures for antibiotics is antimicrobial peptide ..."
Abstract
- Add to MetaCart
(Show Context)
Increasing prevalence of bacteria that carries resistance towards conventional antibiotics has prompted the investigation into new compounds for bacterial intervention to ensure efficient infection control in the future. One group of potential lead structures for antibiotics is antimicrobial peptides (AMPs) due to their characteristics as naturally derived compounds with antimicrobial activity. In that perspective, this thesis seeks to characterize the mechanism of action of small library of in silico optimized peptides. Following determination of peptide activity against E.coli, S.aureus and P.aeruginosa, toxicity was assessed revealing meaningful therapeutic indexes for the far majority of the peptides. Investigation of the peptides effect on bacteria uncovered rapid inhibition with signs of bacterial lysis together with increased bacterial size. Both visual and quantitative assays clearly demonstrated bacterial membrane disruption after 10 minutes, although signs of reestablished membrane integrity at lower concentrations were observed after two hours. The membrane disrupting effect was verified by measuring the release of calcein from bacterial mimicking liposomes. This uncovered the most active peptides as inducers of immediate release, indicating the kinetics of membrane permeabilization as an important determinant of bacterial activity. No secondary structure of peptides in the presence of different liposomes was observed, implying that this feature is not essential for bacterial and cytotoxic activity within this library of peptides. In conjunction, these findings provide strong indications of membrane disruption as the primary mechanism of bacterial inhibition for the tested peptides. RESUMÉ En stadig stigende forekomst af bakterier med resistens overfor konventionelle antibiotika har
skin-derived antimicrobial proteins
, 2005
"... Psoriatic scales: a promising source for the isolation of human ..."
(Show Context)
unknown title
"... A cutaneous gene therapy approach to treat infection through keratinocyte-targeted overexpression of antimicrobial peptides ..."
Abstract
- Add to MetaCart
(Show Context)
A cutaneous gene therapy approach to treat infection through keratinocyte-targeted overexpression of antimicrobial peptides
Interaction and Cellular Localization of the Human Host Defense
, 2004
"... LL-37 is a human cationic host defense peptide that is an essential component of innate immunity. In addition to its modest antimicrobial activity, LL-37 affects the gene expression and behavior of effector cells involved in the innate immune response, although its mode of interaction with eukaryoti ..."
Abstract
- Add to MetaCart
(Show Context)
LL-37 is a human cationic host defense peptide that is an essential component of innate immunity. In addition to its modest antimicrobial activity, LL-37 affects the gene expression and behavior of effector cells involved in the innate immune response, although its mode of interaction with eukaryotic cells remains unclear. The interaction of LL-37 with epithelial cells was characterized in tissue culture by using biotinylated LL-37 and confocal microscopy. It was demonstrated that LL-37 was actively taken up into A549 epithelial cells and eventually localized to the perinuclear region. Specific inhibitors were used to demonstrate that the uptake process was not mediated by actin but required elements normally involved in endocytosis and that trafficking to the perinuclear region was dependent on microtubules. By using nonlinear regression analysis, it was revealed that A549 epithelial cells have two receptors for LL-37B, with high and low affinity for LL-37, respectively. These results indicate the mode of interaction of LL-37 with epithelial cells and further our understanding of its role in modulating the innate immune response. Cationic host defense peptides are key components of innate immunity that have both direct, broad-spectrum antimicrobial activity and an ability to stimulate immunity against bacteria, fungi, parasites, and viruses (14). In evolutionary terms, the
