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cationic antimicrobial peptide

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https://www.readbyqxmd.com/read/28344161/cross-resistance-to-human-cationic-antimicrobial-peptides-and-to-polymyxins-mediated-by-the-plasmid-encoded-mcr-1
#1
Jan Dobias, Laurent Poirel, Patrice Nordmann
OBJECTIVES: To evaluate whether acquired resistance to cationic antimicrobial peptides (CAMP) group molecules, being normal components of the human immune system, may select co-resistance to antibiotic peptides such as polymyxins, considering they share the same mechanism of action. We aimed to evaluate strains producing the recently identified plasmid-encoded polymyxin resistance determinant MCR-1, which is a phosphoethanolamine transferase that modifies the lipopolysaccharide structure of Gram-negative bacteria...
March 23, 2017: Clinical Microbiology and Infection
https://www.readbyqxmd.com/read/28339295/antifungal-plant-defensins-increased-insight-in-their-mode-of-action-as-a-basis-for-their-use-to-combat-fungal-infections
#2
Tanne L Cools, Caroline Struyfs, Bruno Pa Cammue, Karin Thevissen
Plant defensins are small, cationic peptides with a highly conserved 3D structure. They have been studied extensively in the past decades. Various biological activities have been attributed to plant defensins, such as anti-insect and antimicrobial activities, but they are also known to affect ion channels and display antitumor activity. This review focuses on the structure, biological activity and antifungal mode of action of some well-characterized plant defensins, with particular attention to their fungal membrane target(s), their induced cell death mechanisms as well as their antibiofilm activity...
March 24, 2017: Future Microbiology
https://www.readbyqxmd.com/read/28332637/evaluation-of-the-immunomodulatory-activity-of-the-chicken-nk-lysin-derived-peptide-cnk-2
#3
Woo H Kim, Hyun S Lillehoj, Wongi Min
Chicken NK-lysin (cNK-lysin), the chicken homologue of human granulysin, is a cationic amphiphilic antimicrobial peptide (AMP) that is produced by cytotoxic T cells and natural killer cells. We previously demonstrated that cNK-lysin and cNK-2, a synthetic peptide incorporating the core α-helical region of cNK-lysin, have antimicrobial activity against apicomplexan parasites such as Eimeria spp., via membrane disruption. In addition to the antimicrobial activity of AMPs, the immunomodulatory activity of AMPs mediated by their interactions with host cells is increasingly recognized...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28314993/comparative-analysis-of-internalisation-haemolytic-cytotoxic-and-antibacterial-effect-of-membrane-active-cationic-peptides-aspects-of-experimental-setup
#4
Kata Horváti, Bernadett Bacsa, Tamás Mlinkó, Nóra Szabó, Ferenc Hudecz, Ferenc Zsila, Szilvia Bősze
Cationic peptides proved fundamental importance as pharmaceutical agents and/or drug carrier moieties functioning in cellular processes. The comparison of the in vitro activity of these peptides is an experimental challenge and a combination of different methods, such as cytotoxicity, internalisation rate, haemolytic and antibacterial effect, is necessary. At the same time, several issues need to be addressed as the assay conditions have a great influence on the measured biological effects and the experimental setup needs to be optimised...
March 17, 2017: Amino Acids
https://www.readbyqxmd.com/read/28301157/identification-of-the-crucial-residues-in-the-early-insertion-of-pardaxin-into-different-phospholipid-bilayers
#5
Majid Jafari, Faramarz Mehrnejad, Raheleh Aghdami, Nader Chaparzadeh, Zahra Razaghi Moghadam Kashani, Farahnoosh Doustdar
Antimicrobial peptides (AMPs) are part of the innate host defense system, and they are produced by living organisms to defend themselves against infections. Pardaxin is a cationic AMP with antimicrobial and antitumor activities that has potential to be used as a novel antibiotic or for drug delivery in cancer therapy. This peptide acts on the membrane of target cells and can lead to lysis using different mechanisms of action. Here, we conducted 4.5 μs all-atom molecular dynamics (MD) simulations to determine the critical fragments and residues of Pardaxin for early insertion into different lipid bilayers...
March 27, 2017: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/28299840/antimicrobial-activity-and-stability-of-protonectin-with-d-amino-acid-substitutions
#6
Shuai Qiu, Ranran Zhu, Yanyan Zhao, Xiaoping An, Fengjing Jia, Jinxiu Peng, Zelin Ma, Yuanyuan Zhu, Jiayi Wang, Jinhuan Su, Qingjun Wang, Hailin Wang, Yuan Li, Kairong Wang, Wenjin Yan, Rui Wang
The misuse and overuse of antibiotics result in the emergence of resistant bacteria and fungi, which make an urgent need of the new antimicrobial agents. Nowadays, antimicrobial peptides have attracted great attention of researchers. However, the low physiological stability in biological system limits the application of naturally occurring antimicrobial peptides as novel therapeutics. In the present study, we synthesized derivatives of protonectin by substituting all the amino acid residues or the cationic lysine residue with the corresponding D-amino acids...
March 16, 2017: Journal of Peptide Science: An Official Publication of the European Peptide Society
https://www.readbyqxmd.com/read/28296935/peptide-modification-results-in-the-formation-of-a-dimer-with-a-60-fold-enhanced-antimicrobial-activity
#7
Amal Thamri, Myriam Létourneau, Alex Djoboulian, David Chatenet, Eric Déziel, Annie Castonguay, Jonathan Perreault
Cationic antimicrobial peptides (CAMPs) occur naturally in numerous organisms and are considered as a class of antibiotics with promising potential against multi-resistant bacteria. Herein, we report a strategy that can lead to the discovery of novel small CAMPs with greatly enhanced antimicrobial activity and retained antibiofilm potential. We geared our efforts towards i) the N-terminal cysteine functionalization of a previously reported small synthetic cationic peptide (peptide 1037, KRFRIRVRV-NH2), ii) its dimerization through a disulfide bond, and iii) a preliminary antimicrobial activity assessment of the newly prepared dimer against Pseudomonas aeruginosa and Burkholderia cenocepacia, pathogens responsible for the formation of biofilms in lungs of individuals with cystic fibrosis...
2017: PloS One
https://www.readbyqxmd.com/read/28282123/influence-of-the-length-and-charge-on-the-activity-of-%C3%AE-helical-amphipathic-antimicrobial-peptides
#8
Marie-Claude Gagnon, Erik Strandberg, Ariadna Grau-Campistany, Parvesh Wadhwani, Johannes Reichert, Jochen Bürck, Francesc Rabanal, Michèle Auger, Jean-François Paquin, Anne S Ulrich
Hydrophobic mismatch is important for pore-forming amphipathic antimicrobial peptides, as demonstrated recently [Grau-Campistany, A., et al. (2015) Sci. Rep. 5, 9388]. A series of different length peptides have been generated with the heptameric repeat sequence KIAGKIA, called KIA peptides, and it was found that only those helices sufficiently long to span the hydrophobic thickness of the membrane could induce leakage in lipid vesicles; there was also a clear length dependence of the antimicrobial and hemolytic activities...
March 10, 2017: Biochemistry
https://www.readbyqxmd.com/read/28275774/antibiotic-gold-tethering-of-antimicrobial-peptides-to-gold-nanoparticles-maintains-conformational-flexibility-of-peptides-and-improves-trypsin-susceptibility
#9
Parvesh Wadhwani, Nico Heidenreich, Benjamin Podeyn, Jochen Bürck, Anne S Ulrich
Peptide-coated nanoparticles are valuable tools for diverse biological applications, such as drug delivery, molecular recognition, and antimicrobial action. The functionalization of pre-fabricated nanoparticles with free peptides in solution is inefficient either due to aggregation of the particles or due to the poor ligand exchange reaction. Here, we present a one-pot synthesis for preparing gold nanoparticles with a homogeneous distribution that are covered in situ with cationic peptides in a site-selective manner via Cys-residue at the N-terminus...
March 9, 2017: Biomaterials Science
https://www.readbyqxmd.com/read/28272373/%C3%AE-defensins-in-the-fight-against-helicobacter-pylori
#10
REVIEW
Raffaela Pero, Lorena Coretti, Ersilia Nigro, Francesca Lembo, Sonia Laneri, Barbara Lombardo, Aurora Daniele, Olga Scudiero
Antimicrobial peptides (AMPs) play a pivotal role in the innate immune responses to Helicobacter pylori (Hp) in humans. β-Defensins, a class of cationic arginine-rich AMPs, are small peptides secreted by immune cells and epithelial cells that exert antimicrobial activity against a broad spectrum of microorganisms, including Gram-positive and Gram-negative bacteria and fungi. During Hp infections, AMP expression is able to eradicate the bacteria, thereby preventing Hp infections in gastrointestinal tract. It is likely that gastric β-defensins expression is increased during Hp infection...
March 7, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28271058/peptides-with-dual-antimicrobial-and-anticancer-activities
#11
REVIEW
Mário R Felício, Osmar N Silva, Sônia Gonçalves, Nuno C Santos, Octávio L Franco
In recent years, the number of people suffering from cancer and multi-resistant infections has increased, such that both diseases are already seen as current and future major causes of death. Moreover, chronic infections are one of the main causes of cancer, due to the instability in the immune system that allows cancer cells to proliferate. Likewise, the physical debility associated with cancer or with anticancer therapy itself often paves the way for opportunistic infections. It is urgent to develop new therapeutic methods, with higher efficiency and lower side effects...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28259411/genetic-and-functional-analysis-of-the-bovine-uterine-microbiota-part-ii-purulent-vaginal-discharge-versus-healthy-cows
#12
M L S Bicalho, S Lima, C H Higgins, V S Machado, F S Lima, R C Bicalho
The aim of this study was to characterize, using metagenomic shotgun DNA sequencing, the intrauterine microbial population and its predicted functional diversity within healthy cows and cows presenting purulent vaginal discharge (PVD). Twenty Holstein dairy cows from a single farm were enrolled in the study at 25 to 35 d postpartum. Purulent vaginal discharge was diagnosed by retrieving and scoring vaginal discharge using the Metricheck device (Simcro, Hamilton, New Zealand). Intrauterine samples for metagenomic analysis were collected by the cytobrush technique from 8 cows diagnosed with PVD and 12 healthy cows...
March 2, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28258530/catesbeianin-1-a-novel-antimicrobial-peptide-isolated-from-the-skin-of-lithobates-catesbeianus-american-bullfrog
#13
Huihui Xu, Yang Zhang, Xin Feng, Kunyuan Tie, Yuan Cao, Wenyu Han
OBJECTIVES: To identify and characterize a novel antimicrobial peptide, catesbeianin-1. RESULTS: Catesbeianin-1 is 25 amino acids long and is α-helical, cationic and amphipathic. It had antimicrobial activity against Gram-positive and Gram-negative bacteria. It was resistant against trypsin and pepsin. Catesbeianin-1 exhibited moderate hemolytic activity (approx 8%) at 100 μg/ml, and its HC50 (50% hemolytic concentration) was 300 μg/ml. Its cytotoxicity was approx 10-20% at 100 μg/ml, and its CC50 (50% cytotoxic concentration) was >100 μg/ml...
March 3, 2017: Biotechnology Letters
https://www.readbyqxmd.com/read/28257520/lactoferrin-binding-protein-b-a-bi-functional-bacterial-receptor-protein
#14
Nicholas K H Ostan, Rong-Hua Yu, Dixon Ng, Christine Chieh-Lin Lai, Anastassia K Pogoutse, Vladimir Sarpe, Morgan Hepburn, Joey Sheff, Shaunak Raval, David C Schriemer, Trevor F Moraes, Anthony B Schryvers
Lactoferrin binding protein B (LbpB) is a bi-lobed outer membrane-bound lipoprotein that comprises part of the lactoferrin (Lf) receptor complex in Neisseria meningitidis and other Gram-negative pathogens. Recent studies have demonstrated that LbpB plays a role in protecting the bacteria from cationic antimicrobial peptides due to large regions rich in anionic residues in the C-terminal lobe. Relative to its homolog, transferrin-binding protein B (TbpB), there currently is little evidence for its role in iron acquisition and relatively little structural and biophysical information on its interaction with Lf...
March 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28252016/an-antimicrobial-peptide-resistant-minor-subpopulation-of-photorhabdus-luminescens-is-responsible-for-virulence
#15
Annabelle Mouammine, Sylvie Pages, Anne Lanois, Sophie Gaudriault, Gregory Jubelin, Maurine Bonabaud, Stéphane Cruveiller, Emeric Dubois, David Roche, Ludovic Legrand, Julien Brillard, Alain Givaudan
Some of the bacterial cells in isogenic populations behave differently from others. We describe here how a new type of phenotypic heterogeneity relating to resistance to cationic antimicrobial peptides (CAMPs) is determinant for the pathogenic infection process of the entomopathogenic bacterium Photorhabdus luminescens. We demonstrate that the resistant subpopulation, which accounts for only 0.5% of the wild-type population, causes septicemia in insects. Bacterial heterogeneity is driven by the PhoPQ two-component regulatory system and expression of pbgPE, an operon encoding proteins involved in lipopolysaccharide (LPS) modifications...
March 2, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28248490/through-the-lipopolysaccharide-glass-a-potent-antimicrobial-peptide-induces-phase-changes-in-membranes
#16
Damien Jefferies, Pin-Chia Hsu, Syma Khalid
In the following, molecular simulations are used to reveal unexpected behavior within bacterial membranes. We show that lipopolysaccharide molecules found in these membranes form viscous amorphous solids when they are interlinked with monovalent and divalent cations. The bilayers exhibit both liquid and glassy characteristics, due to the coexistence of both liquid and crystalline domains in the bilayer. Polymyxin B1, a potent antimicrobial peptide, is shown to increase order within the lipopolysaccharide bilayers by inducing the formation of crystalline patches...
March 7, 2017: Biochemistry
https://www.readbyqxmd.com/read/28236791/lipid-selectivity-in-novel-antimicrobial-peptides-implication-on-antimicrobial-and-hemolytic-activity
#17
P Maturana, M Martinez, M E Noguera, N C Santos, E A Disalvo, L Semorile, P C Maffia, A Hollmann
Antimicrobial peptides (AMPs) are small cationic molecules that display antimicrobial activity against a wide range of bacteria, fungi and viruses. For an AMP to be considered as a therapeutic option, it must have not only potent antibacterial properties but also low hemolytic and cytotoxic activities [1]. Even though many studies have been conducted in order to correlate the antimicrobial activity with affinity toward model lipid membranes, the use of these membranes to explain cytotoxic effects (especially hemolysis) has been less explored...
February 13, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28216428/antimicrobial-potency-of-cationic-antimicrobial-peptides-can-be-predicted-from-their-amino-acid-composition-application-to-the-detection-of-cryptic-antimicrobial-peptides
#18
Katia Pane, Lorenzo Durante, Orlando Crescenzi, Valeria Cafaro, Elio Pizzo, Mario Varcamonti, Anna Zanfardino, Viviana Izzo, Alberto Di Donato, Eugenio Notomista
Cationic antimicrobial peptides (CAMPs) are essential components of innate immunity. Here we show that antimicrobial potency of CAMPs is linearly correlated to the product C(m)H(n)L where C is the net charge of the peptide, H is a measure of its hydrophobicity and L its length. Exponents m and n define the relative contribution of charge and hydrophobicity to the antimicrobial potency. Very interestingly the values of m and n are strain specific. The ratio n/(m+n) can vary between ca. 0.5 and 1, thus indicating that some strains are sensitive to highly charged peptides, whereas others are particularly susceptible to more hydrophobic peptides...
February 17, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28212487/interactions-between-membranes-and-metaphilic-polypeptide-architectures-with-diverse-side-chain-populations
#19
Michelle W Lee, Ming Han, Guilherme Volpe Bossa, Carly Snell, Ziyuan Song, Haoyu Tang, Lichen Yin, Jianjun Cheng, Sylvio May, Erik Luijten, Gerard C L Wong
At physiological conditions, most proteins or peptides can fold into relatively stable structures that present on their molecular surfaces specific chemical patterns partially smeared out by thermal fluctuations. These nanoscopically defined patterns of charge, hydrogen bonding, and/or hydrophobicity, along with their elasticity and shape stability (folded proteins have Young's moduli of ∼1 × 10(8) Pa), largely determine and limit the interactions of these molecules, such as molecular recognition and allosteric regulation...
March 28, 2017: ACS Nano
https://www.readbyqxmd.com/read/28203238/differential-ability-of-bovine-antimicrobial-cathelicidins-to-mediate-nucleic-acid-sensing-by-epithelial-cells
#20
Arnaud Baumann, Mirjam Susanna Kiener, Brendan Haigh, Vincent Perreten, Artur Summerfield
Cathelicidins encompass a family of cationic peptides characterized by antimicrobial activity and other functions, such as the ability to enhance the sensing of nucleic acids by the innate immune system. The present study aimed to investigate the ability of the bovine cathelicidins indolicidin, bactenecin (Bac)1, Bac5, bovine myeloid antimicrobial peptide (BMAP)-27, BMAP-28, and BMAP-34 to inhibit the growth of bacteria and to enhance the sensing of nucleic acid by the host's immune system. BMAP-27 was the most effective at killing Staphylococcus aureus, Streptococcus uberis, and Escherichia coli, and this was dependent on its amphipathic structure and cationic charge...
2017: Frontiers in Immunology
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