The Experts below are selected from a list of 5973 Experts worldwide ranked by ideXlab platform
Robert E. W. Hancock - One of the best experts on this subject based on the ideXlab platform.
-
ecdbs1r6 a novel Cationic Antimicrobial Peptide derived from a signal Peptide sequence
Biochimica et Biophysica Acta, 2020Co-Authors: William F. Porto, Suzana M. Ribeiro, Luz N. Irazazabal, Robert E. W. Hancock, Vincent Humblot, Evan F Haney, Ali Ladram, Octavio L FrancoAbstract:Abstract Background Bacterial infections represent a major worldwide health problem the Antimicrobial Peptides (AMPs) have been considered as potential alternative agents for treating these infections. Here we demonstrated the Antimicrobial activity of EcDBS1R6, a Peptide derived from a signal Peptide sequence of Escherichia coli that we previously turned into an AMP by making changes through the Joker algorithm. Methods Antimicrobial activity was measured by broth microdilution method. Membrane integrity was measured using fluorescent probes and through scanning electron microscopy imaging. A sliding window of truncated Peptides was used to determine the EcDBS1R6 active core. Molecular dynamics in TFE/water environment was used to assess the EcDBS1R6 structure. Results Signal Peptides are known to naturally interact with membranes; however, the modifications introduced by Joker transformed this Peptide into a membrane-active agent capable of killing bacteria. The C-terminus was unable to fold into an α-helix whereas its fragments showed poor or no Antimicrobial activity, suggesting that the EcDBS1R6 antibacterial core was located at the helical N-terminus, corresponding to the signal Peptide portion of the parent Peptide. Conclusion The strategy of transforming signal Peptides into AMPs appears to be promising and could be used to produce novel Antimicrobial agents. General significance The process of transforming an inactive signal Peptide into an Antimicrobial Peptide could open a new venue for creating new AMPs derived from signal Peptides.
-
Antibacterial surfaces based on polymer brushes: investigation on the influence of brush properties on Antimicrobial Peptide immobilization and Antimicrobial activity.
Biomacromolecules, 2011Co-Authors: Kai Yu, Jason Kindrachuk, Donald E Brooks, Robert E. W. Hancock, Jayachandran N. KizhakkedathuAbstract:Primary amine containing copolymer, poly(N,N-dimethylacrylamide-co-N-(3-aminopropyl)methacrylamide hydrochloride) (poly(DMA-co-APMA)), brushes were synthesized on Ti surface by surface-initiated atom transfer radical polymerization (SI-ATRP) in aqueous conditions. A series of poly(DMA-co-APMA) copolymer brushes on titanium (Ti) surface with different molecular weights, thicknesses, compositions, and graft densities were synthesized by changing the SI-ATRP reaction conditions. Cysteine-functionalized Cationic Antimicrobial Peptide Tet213 (KRWWKWWRRC) was conjugated to the copolymers brushes using a maleimide–thiol addition reaction after initial modification of the grafted chains using 3-maleimidopropionic acid N-hydroxysuccinimide ester. The modified surfaces were characterized by X-ray photoelectron spectroscopy (XPS), water contact angle measurements, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), and ellipsometry analysis. The conjugation...
-
The sensor kinase PhoQ mediates virulence in Pseudomonas aeruginosa.
Microbiology, 2009Co-Authors: W James Gooderham, Shaan L Gellatly, François Sanschagrin, Joseph B Mcphee, Manjeet Bains, Celine Cosseau, Roger C Levesque, Robert E. W. HancockAbstract:Pseudomonas aeruginosa is a ubiquitous environmental Gram-negative bacterium that is also a major opportunistic human pathogen in nosocomial infections and cystic fibrosis chronic lung infections. PhoP-PhoQ is a two-component regulatory system that has been identified as essential for virulence and Cationic Antimicrobial Peptide resistance in several other Gram-negative bacteria. This study demonstrated that mutation of phoQ caused reduced twitching motility, biofilm formation and rapid attachment to surfaces, 2.2-fold reduced cytotoxicity to human lung epithelial cells, substantially reduced lettuce leaf virulence, and a major, 10 000-fold reduction in competitiveness in chronic rat lung infections. Microarray analysis revealed that PhoQ controlled the expression of many genes consistent with these phenotypes and with its known role in polymyxin B resistance. It was also demonstrated that PhoQ controls the expression of many genes outside the known PhoP regulon.
-
structure activity relationships for the β hairpin Cationic Antimicrobial Peptide polyphemusin i
Biochimica et Biophysica Acta, 2004Co-Authors: Jonpaul S Powers, Annett Rozek, Robert E. W. HancockAbstract:Abstract The solution structure of polyphemusin I was determined using 1H-NMR spectroscopy. Polyphemusin I was found to be an amphipathic, β-hairpin connected by a type I′ β-turn. The 17 low-energy structures aligned very well over the β-sheet region while both termini were poorly defined due in part to a hinge-like region centred in the molecule about arginine residues 6 and 16. Conversely, a linear analogue, PM1-S, with all cysteines simultaneously replaced with serine was found to be dynamic in nature, and a lack of medium and long-range NOEs indicated that this molecule displayed no favoured conformation. Circular dichroism (CD) spectroscopy confirmed that in solution, 50% trifluoroethanol (TFE) and in the presence of liposomes, PM1-S remained unstructured. The Antimicrobial activity of PM1-S was found to be 4- to 16-fold less than that of polyphemusin I and corresponded with a 4-fold reduction in bacterial membrane depolarization. Both Peptides were able to associate with lipid bilayers in a similar fashion; however, PM1-S was completely unable to translocate model membranes while polyphemusin I retained this activity. It was concluded that the disulfide-constrained, β-sheet structure of polyphemusin I is required for maximum Antimicrobial activity. Disruption of this structure results in reduced Antimicrobial activity and completely abolishes membrane translocation indicating that the linear PM1-S acts through a different Antimicrobial mechanism.
-
the Cationic Antimicrobial Peptide ll 37 modulates dendritic cell differentiation and dendritic cell induced t cell polarization
Journal of Immunology, 2004Co-Authors: Donald J Davidson, Robert E. W. Hancock, Andrew J Currie, Gregor S D Reid, Dawn M E Bowdish, Kelly L Macdonald, Rebecca C, David P SpeertAbstract:Dendritic cells (DC) are instrumental in orchestrating an appropriately polarized Th cell response to pathogens. DC exhibit considerable phenotypic and functional plasticity, influenced by lineage, Ag engagement, and the environment in which they develop and mature. In this study, we identify the human Cationic Peptide LL-37, found in abundance at sites of inflammation, as a potent modifier of DC differentiation, bridging innate and adaptive immune responses. LL-37-derived DC displayed significantly up-regulated endocytic capacity, modified phagocytic receptor expression and function, up-regulated costimulatory molecule expression, enhanced secretion of Th-1 inducing cytokines, and promoted Th1 responses in vitro. LL-37 may be an attractive therapeutic candidate for manipulating T cell polarization by DC.
Sirlei Daffre - One of the best experts on this subject based on the ideXlab platform.
-
therapeutic use of a Cationic Antimicrobial Peptide from the spider acanthoscurria gomesiana in the control of experimental candidiasis
BMC Microbiology, 2012Co-Authors: Diego C P Rossi, Julian E Munoz, Danielle D Carvalho, Rodrigo Belmonte, Bluma Faintuch, Primavera Borelli, Antonio Miranda, Carlos Pelleschi Taborda, Sirlei DaffreAbstract:Background: Antimicrobial Peptides are present in animals, plants and microorganisms and play a fundamental role in the innate immune response. Gomesin is a Cationic Antimicrobial Peptide purified from haemocytes of the spider Acanthoscurria gomesiana. It has a broad-spectrum of activity against bacteria, fungi, protozoa and tumour cells. Candida albicans is a commensal yeast that is part of the human microbiota. However, in immunocompromised patients, this fungus may cause skin, mucosal or systemic infections. The typical treatment for this mycosis comprises three major categories of antifungal drugs: polyenes, azoles and echinocandins; however cases of resistance to these drugs are frequently reported. With the emergence of microorganisms that are resistant to conventional antibiotics, the development of alternative treatments for candidiasis is important. In this study, we evaluate the efficacy of gomesin treatment on disseminated and vaginal candidiasis as well as its toxicity and biodistribution. Results: Treatment with gomesin effectively reduced Candida albicans in the kidneys, spleen, liver and vagina of infected mice. The biodistribution of gomesin labelled with technetium-99 m showed that the Peptide is captured in the kidneys, spleen and liver. Enhanced production of TNF-a, IFN-g and IL-6 was detected in infected mice treated with gomesin, suggesting an immunomodulatory activity. Moreover, immunosuppressed and C. albicansinfected mice showed an increase in survival after treatment with gomesin and fluconazole. Systemic administration of gomesin was also not toxic to the mice Conclusions: Gomesin proved to be effective against experimental Candida albicans infection. It can be used as an alternative therapy for candidiasis, either alone or in combination with fluconazole. Gomesin’s mechanism is not fully understood, but we hypothesise that the Peptide acts through the permeabilisation of the yeast membrane leading to death and/or releasing the yeast antigens that trigger the host immune response against infection. Therefore, data presented in this study reinforces the potential of gomesin as a therapeutic antifungal agent in both humans and animals.
Jimut Kanti Ghosh - One of the best experts on this subject based on the ideXlab platform.
-
liquid chromatography tandem mass spectrometry based method development and validation of s016 1271 lr8p a novel Cationic Antimicrobial Peptide for its application to pharmacokinetic studies
Journal of Pharmaceutical and Biomedical Analysis, 2019Co-Authors: Santosh Kumar Puttrevu, Jimut Kanti Ghosh, Tulsankar Sachin Laxman, Amit Kumar Tripathi, Anand Kumar Yadav, Sarvesh Verma, Anjali Mishra, Rajesh Pradhan, Neeraj Kumar VermaAbstract:Abstract S016-1271 (LR8P) is a broad spectrum novel Cationic Antimicrobial Peptide. The objective of the present study was to develop a selective liquid chromatography–tandem mass spectrometry (LC–MS/MS) based bioanalytical method of S016-1271 Peptide in mice and human plasma in order to uncover its pharmacokinetic aspects. The chromatographic separation of S016-1271 (FR8P as internal standard) was achieved on a Waters™ X select CSH-C18 column (75 × 3.0 mm, 2.5 μ) using mixture of acetonitrile and triple distilled water (TDW) both containing 0.05% formic acid as mobile phase. A seven minute linear gradient method was designed to separate analytes from ion suppression at a flow rate of 0.3 mL/min. The extraction of analytes from mice and human plasma was performed through solid phase extraction technique using mixed mode weak cation exchange cartridge (Thermo SOLA WCX 10 mg 1CC) with an extraction recovery of analytes about 75%. Mass spectrometric detection of S016-1271 and FR8P was performed with optimized multiple reaction monitoring (MRM) transitions (Q1/Q3) at 658.8 [M+3H] 3+/653.2 [M+3H-NH3] 3+ and 443.4 [M+5H]5+ /434.7 [y12-NH3]4+,respectively in positive electrospray ionization (ESI) mode. The linearity in mice and human plasma was established over a concentration range of 7.81–250 ng/mL with regression coefficient (r2 > 0.99). The currently developed method was validated as per US-FDA guidelines and found to be within the acceptable limits. The method was successfully applied to intravenous (IV) pharmacokinetic study in mice wherein the levels were detected upto 24 h. The Peptide demonstrated poor distribution characteristics which were demonstrated through volume of distribution at steady state (202.71 ± 47.02 mL/kg less than total body water of mice; 580 mL/kg). The clearance of the Peptide predominantly occurred through central compartment (central clearance is 25 fold greater than peripheral clearance). Also, the in vitro pharmacokinetic studies demonstrated the stability of S016-1271 in plasma and high plasma protein binding in mice and humans.
-
spermicidal efficacy of vrp a synthetic Cationic Antimicrobial Peptide inducing apoptosis and membrane disruption
Journal of Cellular Physiology, 2018Co-Authors: Prasanta Ghosh, Arpita Bhoumik, Sudipta Saha, Sandipan Mukherjee, Sarfuddin Azmi, Jimut Kanti Ghosh, Sandhya Rekha DungdungAbstract:Presently available contraceptives are mostly hormonal or detergent in nature with numerous side effects like irritation lesion inflammation in vagina alteration of body homeostasis etc. Antimicrobial Peptides with spermicidal activity but without adverse effects may be suitable alternatives. In the present study spermicidal activity of a Cationic Antimicrobial Peptide VRP on human spermatozoa has been elucidated. Progressive forward motility of human spermatozoa was instantly stopped after 100 microM VRP treatment and at 350 microM all kinds of sperm motility ceased within 20 seconds as assessed by the Sander-Cramer assay. The spermicidal effect was confirmed by eosin-nigrosin assay and HOS test. VRP treatment (100microM) in human spermatozoa induced both the intrinsic and extrinsic pathways of apoptosis. TUNEL assay showed VRP treatment significantly disrupted the DNA integrity and changed the mitochondrial membrane permeability as evident from MPTP assay. AFM and SEM results depicted ultra structural changes including disruption of the acrosomal cap and plasma membrane of the head and midpiece region after treatment with 350 microM VRP. MTT assay showed after treatments with 100 microM and 350 microM of VRP for 24 hrs a substantial amount of Lactobacillus acidophilus (about 90% and 75% respectively) remained viable. Hence VRP being a small synthetic Peptide with Antimicrobial and spermicidal activity but tolerable to normal vaginal microflora may be a suitable target for elucidating its contraceptive potentiality. This article is protected by copyright. All rights reserved.
Octavio L Franco - One of the best experts on this subject based on the ideXlab platform.
-
ecdbs1r6 a novel Cationic Antimicrobial Peptide derived from a signal Peptide sequence
Biochimica et Biophysica Acta, 2020Co-Authors: William F. Porto, Suzana M. Ribeiro, Luz N. Irazazabal, Robert E. W. Hancock, Vincent Humblot, Evan F Haney, Ali Ladram, Octavio L FrancoAbstract:Abstract Background Bacterial infections represent a major worldwide health problem the Antimicrobial Peptides (AMPs) have been considered as potential alternative agents for treating these infections. Here we demonstrated the Antimicrobial activity of EcDBS1R6, a Peptide derived from a signal Peptide sequence of Escherichia coli that we previously turned into an AMP by making changes through the Joker algorithm. Methods Antimicrobial activity was measured by broth microdilution method. Membrane integrity was measured using fluorescent probes and through scanning electron microscopy imaging. A sliding window of truncated Peptides was used to determine the EcDBS1R6 active core. Molecular dynamics in TFE/water environment was used to assess the EcDBS1R6 structure. Results Signal Peptides are known to naturally interact with membranes; however, the modifications introduced by Joker transformed this Peptide into a membrane-active agent capable of killing bacteria. The C-terminus was unable to fold into an α-helix whereas its fragments showed poor or no Antimicrobial activity, suggesting that the EcDBS1R6 antibacterial core was located at the helical N-terminus, corresponding to the signal Peptide portion of the parent Peptide. Conclusion The strategy of transforming signal Peptides into AMPs appears to be promising and could be used to produce novel Antimicrobial agents. General significance The process of transforming an inactive signal Peptide into an Antimicrobial Peptide could open a new venue for creating new AMPs derived from signal Peptides.
Jaesam Hwang - One of the best experts on this subject based on the ideXlab platform.
-
anticancer activity of the Antimicrobial Peptide scolopendrasin vii derived from the centipede scolopendra subspinipes mutilans
Journal of Microbiology and Biotechnology, 2015Co-Authors: Dongchul Kang, Jaesam HwangAbstract:: Previously, we performed de novo RNA sequencing of Scolopendra subspinipes mutilans using high-throughput sequencing technology and identified several Antimicrobial Peptide candidates. Among them, a Cationic Antimicrobial Peptide, scolopendrasin VII, was selected based on its physicochemical properties, such as length, charge, and isoelectric point. Here, we assessed the anticancer activities of scolopendrasin VII against U937 and Jurkat leukemia cell lines. The results showed that scolopendrasin VII decreased the viability of the leukemia cells in MTS assays. Furthermore, flow cytometric analysis and acridine orange/ethidium bromide staining revealed that scolopendrasin VII induced necrosis in the leukemia cells. Scolopendrasin VII-induced necrosis was mediated by specific interaction with phosphatidylserine, which is enriched in the membrane of cancer cells. Taken together, these data indicated that scolopendrasin VII induced necrotic cell death in leukemia cells, probably through interaction with phosphatidylserine. The results provide a useful anticancer Peptide candidate and an efficient strategy for new anticancer Peptide development.
-
scolopendin 2 a Cationic Antimicrobial Peptide from centipede and its membrane active mechanism
Biochimica et Biophysica Acta, 2015Co-Authors: Heejeong Lee, Jaesam Hwang, Jaeho Lee, Jae Il Kim, Dong Gun LeeAbstract:Scolopendin 2 is a 16-mer Peptide (AGLQFPVGRIGRLLRK) derived from the centipede Scolopendra subspinipes mutilans. We observed that this Peptide exhibited Antimicrobial activity in a salt-dependent manner against various fungal and bacterial pathogens and showed no hemolytic effect in the range of 1.6 μM to 100 μM. Circular dichroism analysis showed that the Peptide has an α-helical properties. Furthermore, we determined the mechanism(s) of action using flow cytometry and by investigating the release of intracellular potassium. The results showed that the Peptide permeabilized the membranes of Escherichia coli O157 and Candida albicans, resulting in loss of intracellular potassium ions. Additionally, bis-(1,3-dibutylbarbituric acid) trimethine oxonol and 3,3'-dipropylthiacarbocyanine iodide assays showed that the Peptide caused membrane depolarization. Using giant unilamellar vesicles encapsulating calcein and large unilamellar vesicles containing fluorescein isothiocyanate-dextran, which were similar in composition to typical E. coli O157 and C. albicans membranes, we demonstrated that scolopendin 2 disrupts membranes, resulting in a pore size between 4.8 nm and 5.0 nm. Thus, we have demonstrated that a Cationic Antimicrobial Peptide, scolopendin 2, exerts its broad-spectrum Antimicrobial effects by forming pores in the cell membrane.