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cationic antimicrobial peptide

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https://www.readbyqxmd.com/read/29773800/x-ray-structure-of-a-carpet-like-antimicrobial-defensin-phospholipid-membrane-disruption-complex
#1
Michael Järvå, Fung T Lay, Thanh Kha Phan, Cassandra Humble, Ivan K H Poon, Mark R Bleackley, Marilyn A Anderson, Mark D Hulett, Marc Kvansakul
Defensins are cationic antimicrobial peptides expressed throughout the plant and animal kingdoms as a first line of defense against pathogens. Membrane targeting and disruption is a crucial function of many defensins, however the precise mechanism remains unclear. Certain plant defensins form dimers that specifically bind the membrane phospholipids phosphatidic acid (PA) and phosphatidylinositol 4,5-bisphosphate, thereby triggering the assembly of defensin-lipid oligomers that permeabilize cell membranes. To understand this permeabilization mechanism, here we determine the crystal structure of the plant defensin NaD1 bound to PA...
May 17, 2018: Nature Communications
https://www.readbyqxmd.com/read/29765362/tachyplesin-causes-membrane-instability-that-kills-multidrug-resistant-bacteria-by-inhibiting-the-3-ketoacyl-carrier-protein-reductase-fabg
#2
Cunbao Liu, Jialong Qi, Bin Shan, Yanbing Ma
Tachyplesin is a type of cationic β-hairpin antimicrobial peptide discovered in horseshoe crab approximately 30 years ago that is well known for both its potential antimicrobial activities against multidrug-resistant bacteria and its cytotoxicity to mammalian cells. Though its physical interactions with artificial membranes have been well studied, details of its physiological mechanism of action the physiological consequences of its action remain limited. By using the DNA-binding fluorescent dye propidium iodide to monitor membrane integrity, confocal microscopy to assess the intracellular location of FITC-tagged tachyplesin, and RNA sequencing of the differentially expressed genes in four Gram-negative bacteria ( Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae , and Pseudomonas aeruginosa ) treated with lethal or sublethal concentrations of tachyplesin, we found that compared with levofloxacin-treated bacteria, tachyplesin-treated bacteria showed significant effects on the pathways underlying unsaturated fatty acid biosynthesis...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29763807/positional-scanning-library-applied-to-the-human-eosinophil-cationic-protein-rnase3-n-terminus-reveals-novel-and-potent-anti-biofilm-peptides
#3
David Pulido, Guillem Prats-Ejarque, Clara Villalba, Marcel Albacar, Mohammed Moussaoui, David Andreu, Rudolf Volkmer, Marc Torrent, Ester Boix
Eradication of established biofilm communities of pathogenic bacteria is one of the pending challenges in the development of new antimicrobial agents. In particular, the dreaded nosocomial Pseudomonas aeruginosa forms microbial communities that offer an enhanced resistance to conventional antibiotics. Recently, we have described an engineered antimicrobial peptide derived from the human RNase3, also named the eosinophil cationic protein (ECP), RN3 (5-36), which combines bactericidal activity with high cell agglutination and lipopolysaccharide (LPS) affinity...
May 8, 2018: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29753132/prevention-of-eskape-pathogen-biofilm-formation-by-antimicrobial-peptides-wlbu2-and-ll37
#4
Qiao Lin, Berthony Deslouches, Ronald C Montelaro, Y Peter Di
OBJECTIVES: Bacterial biofilm-dependent infections (e.g., cystic fibrosis, surgical sites, and medical implants) are associated with enhanced drug-resistance and thus difficult to eradicate. The goal of this study was to systematically compare three distinct classes of antimicrobial peptides (AMPs) that include the clinically used antibiotic colistin, the natural AMP LL37, the engineered cationic-AMP WLBU2, and four commonly used antibiotics with different bactericidal mechanisms (tobramycin, ciprofloxacin, ceftazidime and vancomycin) for biofilm prevention properties...
May 9, 2018: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/29750913/synthesis-biophysical-and-functional-studies-of-two-bp100-analogues-modified-by-a-hydrophobic-chain-and-a-cyclic-peptide
#5
Gustavo P B Carretero, Greice K V Saraiva, Ana C G Cauz, Magali A Rodrigues, Sumika Kiyota, Karin A Riske, Alcindo A Dos Santos, Marcos F Pinatto-Botelho, Marcelo P Bemquerer, Frederico J Gueiros-Filho, Hernan Chaimovich, Shirley Schreier, Iolanda M Cuccovia
Antimicrobial peptides (AMPs) work as a primary defense against pathogenic microorganisms. BP100, (KKLFKKILKYL-NH2 ), a rationally designed short, highly cationic AMP, acts against many bacteria, displaying low toxicity to eukaryotic cells. Previously we found that its mechanism of action depends on membrane surface charge and on peptide-to-lipid ratio. Here we present the synthesis of two BP100 analogs: BP100‑alanyl‑hexadecyl‑1‑amine (BP100-Ala-NH-C16 H33 ) and cyclo(1‑4)‑d‑Cys1 , Ile2 , Leu3 , Cys4 -BP100 (Cyclo(1‑4)‑cILC-BP100)...
May 8, 2018: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29750860/effect-of-composition-on-antibacterial-activity-of-sequence-defined-cationic-oligoteas
#6
Christine M Artim, Ngoc Nhu Phan, Christopher A Alabi
In response to the urgent need for new antibiotic development strategies, antimicrobial peptides and their synthetic mimetics are being investigated as promising alternatives to traditional antibiotics. To facilitate their development into clinically viable candidates, we need to understand what molecular features and physicochemical properties are needed to induce cell death. Within the context of sequence-defined oligothioetheramides (oligoTEAs), we explore the impact of the cationic pendant group and backbone hydrophobicity on the potency and selectivity of antibacterial oligoTEAs...
May 11, 2018: ACS Infectious Diseases
https://www.readbyqxmd.com/read/29739882/gene-expression-kinetics-governs-stimulus-specific-decoration-of-the-salmonella-outer-membrane
#7
Xinyu Hong, H Deborah Chen, Eduardo A Groisman
Lipid A is the innermost component of the lipopolysaccharide (LPS) molecules that occupy the outer leaflet of the outer membrane in Gram-negative bacteria. Lipid A is recognized by the host immune system and targeted by cationic antimicrobial compounds. In Salmonella enterica serovar Typhimurium, the phosphates of lipid A are chemically modified by enzymes encoded by targets of the transcriptional regulator PmrA. These modifications increase resistance to the cationic peptide antibiotic polymyxin B by reducing the negative charge of the LPS...
May 8, 2018: Science Signaling
https://www.readbyqxmd.com/read/29737852/cooperative-modes-of-action-of-antimicrobial-peptides-characterized-with-atomistic-simulations-a-study-on-cecropin-b
#8
Ya-Wen Hsiao, Magnus Hedström, Valeria Losasso, Sebastian Metz, Jason Crain, Martyn D Winn
Antimicrobial peptides (AMPs) are widely-occurring host defense agents, of interest as one route for addressing the growing problem of multidrug-resistant pathogens. Understanding the mechanisms behind their anti-pathogen activity is instrumental in designing new AMPs. Herein, we present an all-atom molecular dynamics and free energy study on cecropin B (CB), and its constituent domains. We find a cooperative mechanism in which CB inserts into an anionic model membrane with its amphipathic N-terminal segment, supported by the hydrophobic C-terminal segment of a second peptide...
May 8, 2018: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29737262/design-of-bactericidal-peptides-against-escherichia-coli-o157-h7-pseudomonas-aeruginosa-and-methicillin-resistant-staphylococcus-aureus
#9
Jenniffer Cruz, Paola Rondon, Rodrigo Torres, Mauricio Urquiza, Fanny Guzman, Claudio Alvarez, Maria Angeles Abengozar, Daniel A Sierra, Luis Rivas, Roberto Fernandez-Lafuente, Claudia Ortiz
BACKGROUND: Antimicrobial peptides are on the first line of defense against pathogenic microorganisms of many living beings. These compounds are considered natural antibiotics that can overcome bacterial resistance to conventional antibiotics. Due to this characteristic, new peptides with improved properties are quite appealing for designing new strategies for fighting pathogenic bacteria Methods: Sixteen designed peptides were synthesized using Fmoc chemistry; five of them are new cationic antimicrobial peptides (CAMPs) designed using a genetic algorithm that optimizes the antibacterial activity based on selected physicochemical descriptors and 11 analog peptides derived from these five peptides were designed and constructed by single amino acid substitutions...
May 8, 2018: Medicinal Chemistry
https://www.readbyqxmd.com/read/29733880/identification-of-a-novel-antimicrobial-peptide-from-the-sea-star-patiria-pectinifera
#10
Chan-Hee Kim, Hey-Jin Go, Hye Young Oh, Ji Been Park, Tae Kwan Lee, Jung-Kil Seo, Maurice R Elphick, Nam Gyu Park
Antimicrobial peptides (AMPs) are components of innate immunity found in many forms of life. However, there have been no reports of AMPs in sea star (Phylum Echinodermata). Here we report the isolation and characterization of a novel antimicrobial peptide from a coelomic epithelium extract of the sea star Patiria pectinifera. The isolated peptide comprises 38 amino acid residues, is cationic (pI 9.2), has four cysteine residues that form two disulfide bonds (C1-C3 and C2-C4) and is amidated at the C-terminus and is designated P...
May 4, 2018: Developmental and Comparative Immunology
https://www.readbyqxmd.com/read/29719540/a-novel-phop-phoq-regulation-pathway-modulates-the-survival-of-extraintestinal-pathogenic-escherichia-coli-in-macrophages
#11
Xiangkai Zhuge, Yu Sun, Feng Xue, Fang Tang, Jianluan Ren, Dezhi Li, Juanfang Wang, Min Jiang, Jianjun Dai
The extraintestinal pathogenic Escherichia coli (ExPEC) is a typical facultative intracellular bacterial pathogen. Sensing the environmental stimuli and undertaking adaptive change are crucial for ExPEC to successfully colonize in specific extraintestinal niches. The previous studies show that pathogens exploit two-component systems (TCSs) in response to the host environments during its infection. The PhoP/PhoQ is a typical TCS which is ubiquitous in Gram-negative bacteria. However, there is an incompletely understanding about critical regulatory roles of PhoP/PhoQ in ExPEC pathogenesis...
2018: Frontiers in Immunology
https://www.readbyqxmd.com/read/29705276/biophysical-evaluation-of-cardiolipin-content-as-a-regulator-of-the-membrane-lytic-effect-of-antimicrobial-peptides
#12
Laura Hernández-Villa, Marcela Manrique-Moreno, Chad Leidy, Małgorzata Jemioła-Rzemińska, Claudia Ortíz, Kazimierz Strzałka
Cardiolipin is an anionic tetra-acyl chained glycerophospholipid that increases lipid packing levels and induces intrinsic negative curvature in membranes. Cardiolipin is found in Staphylococcus aureus (S. aureus) membranes, where increased levels of this lipid are induced at the expense of diacyl phosphatidylglycerol in response to stress. We investigate cardiolipin as an inhibitor of the lytic activity of the cationic antimicrobial peptides LL-37 and ∆M2 in model systems with varying phosphatidylglycerol/cardiolipin ratios...
April 13, 2018: Biophysical Chemistry
https://www.readbyqxmd.com/read/29703140/molecular-mechanisms-of-an-antimicrobial-peptide-piscidin-lc-pis-in-a-parasitic-protozoan-cryptocaryon-irritans
#13
Ruanni Chen, Yong Mao, Jun Wang, Min Liu, Ying Qiao, Libing Zheng, Yongquan Su, Qiaozhen Ke, Weiqiang Zheng
BACKGROUND: Cryptocaryon irritans is an obligate parasitic ciliate protozoan that can infect various commercially important mariculture fish species and cause high lethality and economic loss. Current methods of controlling this parasite with chemicals or antibiotics are widely considered to be environmentally harmful. Piscidins with broad spectrum antibacterial, antifungal and antiviral activities were found to have potent activity against C. irritans. Little, however, has been understood about the killing mechanisms of piscidins in parasites...
March 12, 2018: BMC Genomics
https://www.readbyqxmd.com/read/29692546/proteomics-assisted-profiling-of-antimicrobial-peptide-signatures-from-black-pepper-piper-nigrum-l
#14
P Umadevi, M Soumya, Johnson K George, M Anandaraj
Plant antimicrobial peptides are the interesting source of studies in defense response as they are essential components of innate immunity which exert rapid defense response. In spite of abundant reports on the isolation of antimicrobial peptides (AMPs) from many sources, the profile of AMPs expressed/identified from single crop species under certain stress/physiological condition is still unknown. This work describes the AMP signature profile of black pepper and their expression upon Phytophthora infection using label-free quantitative proteomics strategy...
May 2018: Physiology and Molecular Biology of Plants: An International Journal of Functional Plant Biology
https://www.readbyqxmd.com/read/29688795/identification-of-antimicrobial-peptides-of-native-and-heated-hydrolysates-from-hen-egg-white-lysozyme
#15
Wilman Carrillo, Mercedes Ramos
Hen eggs are a source of bioactive compounds, of which the hen egg white lysozyme (HEWL) protein. HEWL has a demonstrated antibacterial activity. The aim of this study was to evaluate the antimicrobial activity of native and heated HEWL hydrolysates obtained through hydrolysis with pepsin and to identify their peptides using the reversed phase high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (RP-HPLC-ESI-MS-MS) analysis. Native and heat-treated HEWL was hydrolyzed with pepsin at pH 1...
April 24, 2018: Journal of Medicinal Food
https://www.readbyqxmd.com/read/29684333/effects-of-alterations-of-the-e-coli-lipopolysaccharide-layer-on-membrane-permeabilization-events-induced-by-cecropin-a
#16
Anurag Agrawal, James C Weisshaar
The outermost layer of Gram negative bacteria is composed of a lipopolysaccharide (LPS) network that forms a dense protective hydrophilic barrier against entry of hydrophobic drugs. At low μM concentrations, a large family of cationic polypeptides known as antimicrobial peptides (AMPs) is able to penetrate the LPS layer and permeabilize the outer membrane (OM) and the cytoplasmic membrane (CM), causing cell death. Cecropin A is a well-studied cationic AMP from moth. Here a battery of time-resolved, single-cell microscopy experiments explores how deletion of sugar layers and/or phosphoryl negative charges from the core oligosaccharide layer (core OS) of K12 E...
April 20, 2018: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29682907/effects-of-increasing-hydrophobicity-by-n-terminal-myristoylation-on-the-antibacterial-and-hemolytic-activities-of-the-c-terminal-cationic-segments-of-human-%C3%AE-defensins-1-3
#17
Krishnakumari Viswanatha, Ankeeta Guru, Harikrishna Adicherla, Nagaraj Ramakrishnan
Analogs of the cationic C-terminal segments of human-β-defensins HBD1-3, Phd1-3 with a single disulfide bond, exhibited comparable antimicrobial activity that were salt sensitive. They did not show hemolytic activity. In the present study, N-terminal myristoylation was carried out on Phd1-3 to examine whether increasing hydrophobicity would result in improved antibacterial activity. The antibacterial activity of the oxidized myristoylated peptides MPhd1-3 and their reduced forms MPhd1r-3r was determined. These peptides showed enhanced antibacterial activity as compared to Phd1-3, on mid-log phase and stationary phase of Staphylococcus aureus and Escherichia coli, except MPhd1r-3r that were inactive on stationary phase E...
April 23, 2018: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/29673353/modulation-of-ovine-sbd-1-expression-by-saccharomyces-cerevisiae-in-ovine-ruminal-epithelial-cells
#18
Xin Jin, Man Zhang, Xue-Min Zhu, Yan-Ru Fan, Chen-Guang Du, Hua-Er Bao, Siri-Guleng Xu, Qiao-Zhen Tian, Yun-He Wang, Yin-Feng Yang
BACKGROUND: The ovine rumen is involved in host defense responses and acts as the immune interface with the environment. The ruminal mucosal epithelium plays an important role in innate immunity and secretes antimicrobial innate immune molecules that have bactericidal activity against a variety of pathogens. Defensins are cationic peptides that are produced by the mucosal epithelia and have broad-spectrum antimicrobial activity. Sheep β-defensin-1 (SBD-1) is one of the most important antibacterial peptides in the rumen...
April 19, 2018: BMC Veterinary Research
https://www.readbyqxmd.com/read/29672023/chitosan-based-peptidopolysaccharides-as-cationic-antimicrobial-agents-and-antibacterial-coatings
#19
Dicky Pranantyo, Li Qun Xu, En-Tang Kang, Mary B Chan-Park
The rapid spread of multidrug resistant bacteria has called for effective antimicrobial agents which work on a more direct mechanism of killing. Cationic peptidopolysaccharides are developed in the present work to mimic the peptidoglycan structure of bacteria and to enhance the membrane-compromising bactericidal efficacy. Antimicrobial CysHHC10 peptide was grafted to the C-2 (amino) or C-6 (hydroxyl) position of chitosan backbone via thiol-maleimide 'click' conjugation, utilizing the maleimidohexanoic linkers...
April 19, 2018: Biomacromolecules
https://www.readbyqxmd.com/read/29671805/improving-the-activity-of-trp-rich-antimicrobial-peptides-by-arg-lys-substitutions-and-changing-the-length-of-cationic-residues
#20
Mauricio Arias, Kathlyn B Piga, M Eric Hyndman, Hans J Vogel
Antimicrobial peptides (AMPs) constitute a promising alternative for the development of new antibiotics that could potentially counteract the growing number of antibiotic-resistant bacteria. However, the AMP structure⁻function relationships remain unclear and detailed studies are still necessary. The positively charged amino acid residues (Arg and Lys) play a crucial role in the activity of most AMPs due to the promotion of electrostatic interactions between the peptides and bacterial membranes. In this work we have analyzed the antimicrobial and structural properties of several Trp-rich AMPs containing exclusively either Arg or Lys as the positively charged residues...
April 19, 2018: Biomolecules
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