Journal articles: 'Peptide antimicrobiens'

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Browne, Katrina, Sudip Chakraborty, Renxun Chen, Mark DP Willcox, David StClair Black, William R. Walsh, and Naresh Kumar. "A New Era of Antibiotics: The Clinical Potential of Antimicrobial Peptides." International Journal of Molecular Sciences 21, no. 19 (September 24, 2020): 7047. http://dx.doi.org/10.3390/ijms21197047.

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Antimicrobial resistance is a multifaceted crisis, imposing a serious threat to global health. The traditional antibiotic pipeline has been exhausted, prompting research into alternate antimicrobial strategies. Inspired by nature, antimicrobial peptides are rapidly gaining attention for their clinical potential as they present distinct advantages over traditional antibiotics. Antimicrobial peptides are found in all forms of life and demonstrate a pivotal role in the innate immune system. Many antimicrobial peptides are evolutionarily conserved, with limited propensity for resistance. Additionally, chemical modifications to the peptide backbone can be used to improve biological activity and stability and reduce toxicity. This review details the therapeutic potential of peptide-based antimicrobials, as well as the challenges needed to overcome in order for clinical translation. We explore the proposed mechanisms of activity, design of synthetic biomimics, and how this novel class of antimicrobial compound may address the need for effective antibiotics. Finally, we discuss commercially available peptide-based antimicrobials and antimicrobial peptides in clinical trials.

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Schröder, J. M. "Peptides épithéliaux antimicrobiens." Annales de Dermatologie et de Vénéréologie 131, no. 4 (April 2004): 411–16. http://dx.doi.org/10.1016/s0151-9638(04)93629-0.

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Ruijne, Fleur, and Oscar P. Kuipers. "Combinatorial biosynthesis for the generation of new-to-nature peptide antimicrobials." Biochemical Society Transactions 49, no. 1 (January 13, 2021): 203–15. http://dx.doi.org/10.1042/bst20200425.

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Natural peptide products are a valuable source of important therapeutic agents, including antibiotics, antivirals and crop protection agents. Aided by an increased understanding of structure–activity relationships of these complex molecules and the biosynthetic machineries that produce them, it has become possible to re-engineer complete machineries and biosynthetic pathways to create novel products with improved pharmacological properties or modified structures to combat antimicrobial resistance. In this review, we will address the progress that has been made using non-ribosomally produced peptides and ribosomally synthesized and post-translationally modified peptides as scaffolds for designed biosynthetic pathways or combinatorial synthesis for the creation of novel peptide antimicrobials.

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Fleeman, Renee M., Luis A. Macias, Jennifer S. Brodbelt, and Bryan W. Davies. "Defining principles that influence antimicrobial peptide activity against capsulatedKlebsiella pneumoniae." Proceedings of the National Academy of Sciences 117, no. 44 (October 21, 2020): 27620–26. http://dx.doi.org/10.1073/pnas.2007036117.

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The extracellular polysaccharide capsule ofKlebsiella pneumoniaeresists penetration by antimicrobials and protects the bacteria from the innate immune system. Host antimicrobial peptides are inactivated by the capsule as it impedes their penetration to the bacterial membrane. While the capsule sequesters most peptides, a few antimicrobial peptides have been identified that retain activity against encapsulatedK. pneumoniae,suggesting that this bacterial defense can be overcome. However, it is unclear what factors allow peptides to avoid capsule inhibition. To address this, we created a peptide analog with strong antimicrobial activity toward severalK. pneumoniaestrains from a previously inactive peptide. We characterized the effects of these two peptides onK. pneumoniae, along with their physical interactions withK. pneumoniaecapsule. Both peptides disrupted bacterial cell membranes, but only the active peptide displayed this activity against capsulatedK. pneumoniae. Unexpectedly, the active peptide showed no decrease in capsule binding, but did lose secondary structure in a capsule-dependent fashion compared with the inactive parent peptide. We found that these characteristics are associated with capsule-peptide aggregation, leading to disruption of theK. pneumoniaecapsule. Our findings reveal a potential mechanism for disrupting the protective barrier thatK. pneumoniaeuses to avoid the immune system and last-resort antibiotics.

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Schröder, Jens-Michael, and Jürgen Harder. "Peptides antimicrobiens naturels cutanés." médecine/sciences 22, no. 2 (February 2006): 153–57. http://dx.doi.org/10.1051/medsci/2006222153.

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Dong, Na, Chensi Wang, Xinran Li, Yuming Guo, and Xiaoli Li. "Simplified Head-to-Tail Cyclic Polypeptides as Biomaterial-Associated Antimicrobials with Endotoxin Neutralizing and Anti-Inflammatory Capabilities." International Journal of Molecular Sciences 20, no. 23 (November 25, 2019): 5904. http://dx.doi.org/10.3390/ijms20235904.

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The therapeutic application of antimicrobial peptides (AMPs), a potential type of peptide-based biomaterial, is impeded by their poor antimicrobial activity and potential cytotoxicity as a lack of understanding of their structure–activity relationships. In order to comprehensively enhance the antibacterial and clinical application potency of AMPs, a rational approach was applied to design amphiphilic peptides, including head-to-tail cyclic, linear and D-proline antimicrobial peptides using the template (IR)nP(IR)nP (n = 1, 2 and 3). Results showed that these amphiphilic peptides demonstrated antimicrobial activity in a size-dependent manner and that cyclic peptide OIR3, which contained three repeating units (IR)3, had greater antimicrobial potency and cell selectivity than liner peptide IR3, DIR3 with D-Pro and gramicidin S (GS). Surface plasmon resonance and endotoxin neutralization assays indicated that OIR3 had significant endotoxin neutralization capabilities, which suggested that the effects of OIR3 were mediated by binding to lipopolysaccharides (LPS). Using fluorescence spectrometry and electron microscopy, we found that OIR3 strongly promoted membrane disruption and thereby induced cell lysis. In addition, an LPS-induced inflammation assay showed that OIR3 inhibited the pro-inflammatory factor TNF-α in RAW264.7 cells. OIR3 was able to reduce oxazolone-induced skin inflammation in allergic dermatitis mouse model via the inhibition of TNF-α, IL-1β and IL-6 mRNA expression. Collectively, the engineered head-to-tail cyclic peptide OIR3 was considerable potential candidate for use as a clinical therapeutic for the treatment of bacterial infections and skin inflammation.

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Haney, Evan F., Leonard T. Nguyen, David J. Schibli, and Hans J. Vogel. "Design of a novel tryptophan-rich membrane-active antimicrobial peptide from the membrane-proximal region of the HIV glycoprotein, gp41." Beilstein Journal of Organic Chemistry 8 (July 24, 2012): 1172–84. http://dx.doi.org/10.3762/bjoc.8.130.

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A number of physicochemical characteristics have been described which contribute to the biological activity of antimicrobial peptides. This information was used to design a novel antimicrobial peptide sequence by using an intrinsically inactive membrane-associated peptide derived from the HIV glycoprotein, gp41, as a starting scaffold. This peptide corresponds to the tryptophan-rich membrane-proximal region of gp41, which is known to interact at the interfacial region of the viral membrane and adopts a helical structure in the presence of lipids. Three synthetic peptides were designed to increase the net positive charge and amphipathicity of this 19-residue peptide. Ultimately, the peptide with the greatest degree of amphipathicity and largest positive charge proved to be the most potent antimicrobial, and this peptide could be further modified to improve the antimicrobial activity. However, the other two peptides were relatively ineffective antimicrobials and instead proved to be extremely hemolytic. This work demonstrates a novel approach for the design of unexplored antimicrobial peptide sequences but it also reveals that the biological and cytotoxic activities of these polypeptides depend on a number of interrelated factors.

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Kraszewska, Joanna, Michael C. Beckett, Tharappel C. James, and Ursula Bond. "Comparative Analysis of the Antimicrobial Activities of Plant Defensin-Like and Ultrashort Peptides against Food-Spoiling Bacteria." Applied and Environmental Microbiology 82, no. 14 (May 6, 2016): 4288–98. http://dx.doi.org/10.1128/aem.00558-16.

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ABSTRACTAntimicrobial peptides offer potential as novel therapeutics to combat food spoilage and poisoning caused by pathogenic and nonpathogenic bacteria. Our previous studies identified the peptide human beta-defensin 3 (HBD3) as a potent antimicrobial agent against a wide range of beer-spoiling bacteria. Thus, HBD3 is an excellent candidate for development as an additive to prevent food and beverage spoilage. To expand the repertoire of peptides with antimicrobial activity against bacteria associated with food spoilage and/or food poisoning, we carried out anin silicodiscovery pipeline to identify peptides with structure and activity similar to those of HBD3, focusing on peptides of plant origin. Using a standardized assay, we compared the antimicrobial activities of nine defensin-like plant peptides to the activity of HBD3. Only two of the peptides, fabatin-2 and Cp-thionin-2, displayed antimicrobial activity; however, the peptides differed from HBD3 in being sensitive to salt and were thermostable. We also compared the activities of several ultrashort peptides to that of HBD3. One of the peptides, the synthetic tetrapeptide O3TR, displayed biphasic antimicrobial activity but had a narrower host range than HBD3. Finally, to determine if the peptides might act in concert to improve antimicrobial activity, we compared the activities of the peptides in pairwise combinations. The plant defensin-like peptides fabatin-2 and Cp-thionin-2 displayed a synergistic effect with HBD3, while O3TR was antagonistic. Thus, some plant defensin-like peptides are effective antimicrobials and may act in concert with HBD3 to control bacteria associated with food spoilage and food poisoning.IMPORTANCEFood spoilage and food poisoning caused by bacteria can have major health and economic implications for human society. With the rise in resistance to conventional antibiotics, there is a need to identify new antimicrobials to combat these outbreaks in our food supply. Here we screened plant peptide databases to identify peptides that share structural similarity with the human defensin peptide HBD3, which has known antimicrobial activity against food-spoiling bacteria. We show that two of the plant peptides display antimicrobial activity against bacteria associated with food spoilage. When combined with HBD3, the peptides are highly effective. We also analyzed the activity of an easily made ultrashort synthetic peptide, O3TR. We show that this small peptide also displays antimicrobial activity against food-spoiling bacteria but is not as effective as HBD3 or the plant peptides. The plant peptides identified are good candidates for development as natural additives to prevent food spoilage.

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Małuch, Izabela, Oktawian Stachurski, Paulina Kosikowska-Adamus, Marta Makowska, Marta Bauer, Dariusz Wyrzykowski, Aleksandra Hać, et al. "Double-Headed Cationic Lipopeptides: An Emerging Class of Antimicrobials." International Journal of Molecular Sciences 21, no. 23 (November 25, 2020): 8944. http://dx.doi.org/10.3390/ijms21238944.

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Antimicrobial peptides (AMPs) constitute a promising tool in the development of novel therapeutic agents useful in a wide range of bacterial and fungal infections. Among the modifications improving pharmacokinetic and pharmacodynamic characteristics of natural AMPs, an important role is played by lipidation. This study focuses on the newly designed and synthesized lipopeptides containing multiple Lys residues or their shorter homologues with palmitic acid (C16) attached to the side chain of a residue located in the center of the peptide sequence. The approach resulted in the development of lipopeptides representing a model of surfactants with two polar headgroups. The aim of this study is to explain how variations in the length of the peptide chain or the hydrocarbon side chain of an amino acid residue modified with C16, affect biological functions of lipopeptides, their self-assembling propensity, and their mode of action.

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Shao, Changxuan, Weizhong Li, Peng Tan, Anshan Shan, Xiujing Dou, Deying Ma, and Chunyu Liu. "Symmetrical Modification of Minimized Dermaseptins to Extend the Spectrum of Antimicrobials with Endotoxin Neutralization Potency." International Journal of Molecular Sciences 20, no. 6 (March 20, 2019): 1417. http://dx.doi.org/10.3390/ijms20061417.

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Antimicrobial peptides (AMPs) have emerged as a promising class of antimicrobial agents that could potentially address the global antibiotic resistance. Generating mirror-like peptides by minimizing dermaseptin family sequences is an effective strategy for designing AMPs. However, the previous research still had some limitations such as lower effectiveness and a narrow spectrum of antibacterial activity. To further expand and hone this strategy, we designed a series of AMPs consisting of the WXMXW-NH2 motif (X represents V, I, F, and W; M represents KAAAKAAAK). The peptides formed α-helices and displayed broad-spectrum antimicrobial activities against eleven types of clinical bacteria including both Gram-negative and Gram-positive bacteria. The optimized peptide WW exhibited high physical rupture by inducing membrane shrinkage, disruption, and lysis. Moreover, WW effectively neutralized endotoxins and inhibited the inflammatory response while having the highest therapeutic index. In conclusion, these results indicated that the peptide WW has potential as a broad-spectrum antimicrobial agent or preservative for overcoming the risk of multidrug resistance in localized or external therapeutic applications.

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Eckert, Randal, Fengxia Qi, Daniel K. Yarbrough, Jian He, Maxwell H. Anderson, and Wenyuan Shi. "Adding Selectivity to Antimicrobial Peptides: Rational Design of a Multidomain Peptide against Pseudomonas spp." Antimicrobial Agents and Chemotherapy 50, no. 4 (April 2006): 1480–88. http://dx.doi.org/10.1128/aac.50.4.1480-1488.2006.

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ABSTRACT Currently available antimicrobials exhibit broad killing with regard to bacterial genera and species. Indiscriminate killing of microbes by these conventional antibiotics can disrupt the ecological balance of the indigenous microbial flora, often resulting in negative clinical consequences. Species-specific antimicrobials capable of precisely targeting pathogenic bacteria without damaging benign microorganisms provide a means of avoiding this problem. In this communication, we report the successful creation of the first synthetic, target-specific antimicrobial peptide, G10KHc, via addition of a rationally designed Pseudomonas-specific targeting moiety (KH) to a generally killing peptide (novispirin G10). The resulting chimeric peptide showed enhanced bactericidal activity and faster killing kinetics against Pseudomonas spp. than G10 alone. The enhanced killing activities are due to increased binding and penetration of the outer membrane of Pseudomonas sp. cells. These properties were not observed in tests of untargeted bacterial species, and this specificity allowed G10KHc to selectively eliminate Pseudomonas spp. from mixed cultures. This work lays a foundation for generating target-specific “smart” antimicrobials to complement currently available conventional antibiotics.

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Tran, Phat, Jonathan Kopel, Joe A. Fralick, and Ted W. Reid. "The Use of an Organo-Selenium Peptide to Develop New Antimicrobials That Target a Specific Bacteria." Antibiotics 10, no. 6 (May 21, 2021): 611. http://dx.doi.org/10.3390/antibiotics10060611.

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This study examines the use of a covalently selenium-bonded peptide and phage that binds to the Yersinia pestis F1 antigen for the targeting and killing of E. coli expressing this surface antigen. Using a Ph.D.-12 phage-display library for affinity selection of the phage which would bind the F1 antigen of Y. pestis, a phage displaying a peptide that binds the F1 antigen with high affinity and specificity was identified. Selenium was then covalently attached to the display phage and the corresponding F1-antigen-binding peptide. Both the phage and peptides with selenium covalently attached retained their binding specificity for the Y. pestis F1 antigen. The phage or peptide not labeled with selenium did not kill the targeted bacteria, while the phage or peptide labeled with selenium did. In addition, the seleno-peptide, expressing the F1 targeting sequence only, killed cells expressing the F1 antigen but not the parent strain that did not express the F1 antigen. Specifically, the seleno-peptide could kill eight logs of bacteria in less than two hours at a 10-µM concentration. These results demonstrate a novel approach for the development of an antibacterial agent that can target a specific bacterial pathogen for destruction through the use of covalently attached selenium and will not affect other bacteria.

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Nava Lara, Rodrigo, Longendri Aguilera-Mendoza, Carlos Brizuela, Antonio Peña, and Gabriel Del Rio. "Heterologous Machine Learning for the Identification of Antimicrobial Activity in Human-Targeted Drugs." Molecules 24, no. 7 (March 31, 2019): 1258. http://dx.doi.org/10.3390/molecules24071258.

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The emergence of microbes resistant to common antibiotics represent a current treat to human health. It has been recently recognized that non-antibiotic labeled drugs may promote antibiotic-resistance mechanisms in the human microbiome by presenting a secondary antibiotic activity; hence, the development of computer-assisted procedures to identify antibiotic activity in human-targeted compounds may assist in preventing the emergence of resistant microbes. In this regard, it is worth noting that while most antibiotics used to treat human infectious diseases are non-peptidic compounds, most known antimicrobials nowadays are peptides, therefore all computer-based models aimed to predict antimicrobials either use small datasets of non-peptidic compounds rendering predictions with poor reliability or they predict antimicrobial peptides that are not currently used in humans. Here we report a machine-learning-based approach trained to identify gut antimicrobial compounds; a unique aspect of our model is the use of heterologous training sets, in which peptide and non-peptide antimicrobial compounds were used to increase the size of the training data set. Our results show that combining peptide and non-peptide antimicrobial compounds rendered the best classification of gut antimicrobial compounds. Furthermore, this classification model was tested on the latest human-approved drugs expecting to identify antibiotics with broad-spectrum activity and our results show that the model rendered predictions consistent with current knowledge about broad-spectrum antibiotics. Therefore, heterologous machine learning rendered an efficient computational approach to classify antimicrobial compounds.

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Ponnappan, Nisha, Deepthi Poornima Budagavi, Bhoopesh Kumar Yadav, and Archana Chugh. "Membrane-Active Peptides from Marine Organisms—Antimicrobials, Cell-Penetrating Peptides and Peptide Toxins: Applications and Prospects." Probiotics and Antimicrobial Proteins 7, no. 1 (January 6, 2015): 75–89. http://dx.doi.org/10.1007/s12602-014-9182-2.

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Boparai, Jaspreet Kaur, and Pushpender Kumar Sharma. "Mini Review on Antimicrobial Peptides, Sources, Mechanism and Recent Applications." Protein & Peptide Letters 27, no. 1 (December 10, 2019): 4–16. http://dx.doi.org/10.2174/0929866526666190822165812.

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Antimicrobial peptides in recent years have gained increased interest among scientists, health professionals and the pharmaceutical companies owing to their therapeutic potential. These are low molecular weight proteins with broad range antimicrobial and immuno modulatory activities against infectious bacteria (Gram positive and Gram negative), viruses and fungi. Inability of micro-organisms to develop resistance against most of the antimicrobial peptide has made them as an efficient product which can greatly impact the new era of antimicrobials. In addition to this these peptides also demonstrates increased efficacy, high specificity, decreased drug interaction, low toxicity, biological diversity and direct attacking properties. Pharmaceutical industries are therefore conducting appropriate clinical trials to develop these peptides as potential therapeutic drugs. More than 60 peptide drugs have already reached the market and several hundreds of novel therapeutic peptides are in preclinical and clinical development. Rational designing can be used further to modify the chemical and physical properties of existing peptides. This mini review will discuss the sources, mechanism and recent therapeutic applications of antimicrobial peptides in treatment of infectious diseases.

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Tenea, Gabriela N. "Peptide Extracts from Native Lactic Acid Bacteria Generate Ghost Cells and Spheroplasts upon Interaction with Salmonella enterica, as Promising Food Antimicrobials." BioMed Research International 2020 (October 5, 2020): 1–11. http://dx.doi.org/10.1155/2020/6152356.

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Protecting foods from contamination applying peptides produced by lactic acid bacteria is a promising strategy to increase the food quality and safety. Interacting with the pathogen membranes might produce visible changes in shape or cell wall damage. Previously, we showed that the peptides produced by Lactobacillus plantarum UTNGt2, Lactobacillus plantarum UTNCys5-4, and Lactococcus lactis subsp. lactis UTNGt28 exhibit a broad spectrum of antibacterial activity against several foodborne pathogens in vitro. In this study, their possible mode of action against the commensal microorganism Salmonella enterica subsp. enterica ATCC51741 was investigated. The target membrane permeability was determined by detection of beta-galactosidase release from ONPG (o-nitro-phenyl-L-D-galactoside) substrate and changes in the whole protein profile indicating that the peptide extracts destroy the membrane integrity and may induce breaks in membrane proteins to some extent. The release of aromatic molecules such as DNA/RNA was detected after the interaction of Salmonella with the peptide extract. Transmission electronic microscopy (TEM) micrographs depicted at least four simultaneous secondary events after the peptide extract treatment underlying their antimicrobial actions, including morphological alterations of the membrane. Spheroplast and filament formation, vacuolation, and DNA relaxation were identified as the principal events from the Gt2 and Cys5-4 peptide extracts, while Gt28 induced the formation of ghost cells by release of cytoplasmic content, filaments, and separation of cell envelope layers. Gel retarding assays indicate that the Gt2 and Gt28 peptide extracts are clearly binding the Salmonella DNA, while Cys5-4 partially interacted with Salmonella genomic DNA. These results increased our knowledge about the inhibitory mechanism employed by several peptide extracts from native lactic acid bacteria against Salmonella. Further, we shall develop peptide-based formulation and evaluate their biocontrol effect in the food chains.

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Nava Lara, Rodrigo A., Jesús A. Beltrán, Carlos A. Brizuela, and Gabriel Del Rio. "Relevant Features of Polypharmacologic Human-Target Antimicrobials Discovered by Machine-Learning Techniques." Pharmaceuticals 13, no. 9 (August 21, 2020): 204. http://dx.doi.org/10.3390/ph13090204.

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Polypharmacologic human-targeted antimicrobials (polyHAM) are potentially useful in the treatment of complex human diseases where the microbiome is important (e.g., diabetes, hypertension). We previously reported a machine-learning approach to identify polyHAM from FDA-approved human targeted drugs using a heterologous approach (training with peptides and non-peptide compounds). Here we discover that polyHAM are more likely to be found among antimicrobials displaying a broad-spectrum antibiotic activity and that topological, but not chemical features, are most informative to classify this activity. A heterologous machine-learning approach was trained with broad-spectrum antimicrobials and tested with human metabolites; these metabolites were labeled as antimicrobials or non-antimicrobials based on a naïve text-mining approach. Human metabolites are not commonly recognized as antimicrobials yet circulate in the human body where microbes are found and our heterologous model was able to classify those with antimicrobial activity. These results provide the basis to develop applications aimed to design human diets that purposely alter metabolic compounds proportions as a way to control human microbiome.

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Bulet, P. "Les peptides antimicrobiens de la drosophile." médecine/sciences 15, no. 1 (1999): 23. http://dx.doi.org/10.4267/10608/1192.

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Patrzykat, Aleksander, Jeffrey W. Gallant, Jung-Kil Seo, Jennifer Pytyck, and Susan E. Douglas. "Novel Antimicrobial Peptides Derived from Flatfish Genes." Antimicrobial Agents and Chemotherapy 47, no. 8 (August 2003): 2464–70. http://dx.doi.org/10.1128/aac.47.8.2464-2470.2003.

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ABSTRACT We report on the identification of active novel antimicrobials determined by screening both the genomic information and the mRNA transcripts from a number of different flatfish for sequences encoding antimicrobial peptides, predicting the sequences of active peptides from the genetic information, producing the predicted peptides chemically, and testing them for their activities. We amplified 35 sequences from various species of flatfish using primers whose sequences are based on conserved flanking regions of a known antimicrobial peptide from winter flounder, pleurocidin. We analyzed the sequences of the amplified products and predicted which sequences were likely to encode functional antimicrobial peptides on the basis of charge, hydrophobicity, relation to flanking sequences, and similarity to known active peptides. Twenty peptides were then produced synthetically and tested for their activities against gram-positive and gram-negative bacteria and the yeast Candida albicans. The most active peptide (with the carboxy-terminus amidated sequence GWRTLLKKAEVKTVGKLALKHYL, derived from American plaice) showed inhibitory activity over a concentration range of 1 to 8 μg/ml against a test panel of pathogens, including the intrinsically antibiotic-resistant organism Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and C. albicans. The methods described here will be useful for the identification of novel peptides with good antimicrobial activities.

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Fernández, Lucía, W. James Gooderham, Manjeet Bains, Joseph B. McPhee, Irith Wiegand, and Robert E. W. Hancock. "Adaptive Resistance to the “Last Hope” Antibiotics Polymyxin B and Colistin in Pseudomonas aeruginosa Is Mediated by the Novel Two-Component Regulatory System ParR-ParS." Antimicrobial Agents and Chemotherapy 54, no. 8 (June 14, 2010): 3372–82. http://dx.doi.org/10.1128/aac.00242-10.

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ABSTRACT As multidrug resistance increases alarmingly, polymyxin B and colistin are increasingly being used in the clinic to treat serious Pseudomonas aeruginosa infections. In this opportunistic pathogen, subinhibitory levels of polymyxins and certain antimicrobial peptides induce resistance toward higher, otherwise lethal, levels of these antimicrobial agents. It is known that the modification of lipid A of lipopolysaccharide (LPS) is a key component of this adaptive peptide resistance, but to date, the regulatory mechanism underlying peptide regulation in P. aeruginosa has remained elusive. The PhoP-PhoQ and PmrA-PmrB two-component systems, which control this modification under low-Mg2+ conditions, do not appear to play a major role in peptide-mediated adaptive resistance, unlike in Salmonella where PhoQ is a peptide sensor. Here we describe the identification and characterization of a novel P. aeruginosa two-component regulator affecting p olymyxin- a daptive r esistance, ParR-ParS (PA1799-PA1798). This system was required for activation of the arnBCADTEF LPS modification operon in the presence of subinhibitory concentrations of polymyxin, colistin, or the bovine peptide indolicidin, leading to increased resistance to various polycationic antibiotics, including aminoglycosides. This study highlights the complexity of the regulatory network controlling resistance to cationic antibiotics and host peptides in P. aeruginosa, which has major relevance in the development and deployment of cationic antimicrobials.

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Silva, Osmar N., Marcelo D. T. Torres, Jicong Cao, Elaine S. F. Alves, Leticia V. Rodrigues, Jarbas M. Resende, Luciano M. Lião, et al. "Repurposing a peptide toxin from wasp venom into antiinfectives with dual antimicrobial and immunomodulatory properties." Proceedings of the National Academy of Sciences 117, no. 43 (October 12, 2020): 26936–45. http://dx.doi.org/10.1073/pnas.2012379117.

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Novel antibiotics are urgently needed to combat multidrug-resistant pathogens. Venoms represent previously untapped sources of novel drugs. Here we repurposed mastoparan-L, the toxic active principle derived from the venom of the wasp Vespula lewisii, into synthetic antimicrobials. We engineered within its N terminus a motif conserved among natural peptides with potent immunomodulatory and antimicrobial activities. The resulting peptide, mast-MO, adopted an α-helical structure as determined by NMR, exhibited increased antibacterial properties comparable to standard-of-care antibiotics both in vitro and in vivo, and potentiated the activity of different classes of antibiotics. Mechanism-of-action studies revealed that mast-MO targets bacteria by rapidly permeabilizing their outer membrane. In animal models, the peptide displayed direct antimicrobial activity, led to enhanced ability to attract leukocytes to the infection site, and was able to control inflammation. Permutation studies depleted the remaining toxicity of mast-MO toward human cells, yielding derivatives with antiinfective activity in animals. We demonstrate a rational design strategy for repurposing venoms into promising antimicrobials.

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Kopeykin, P. M., M. S. Sukhareva, N. V. Lugovkina, and O. V. Shamova. "CHEMICAL SYNTHESIS AND ANALYSIS OF ANTIMICROBIAL AND HEMOLYTIC ACTIVITY OF STRUCTURAL ANALOGOUS OF A PEPTIDE PROTEGRIN 1." Medical academic journal 19, no. 1S (December 15, 2019): 169–70. http://dx.doi.org/10.17816/maj191s1169-170.

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Search for new tools for combating infectious diseases and investigation of molecular mechanisms of their antimicrobial action in in vitro and in vivo models are the urgent tasks of experimental medicine and pathophysiology. A promising direction for the development of new effective antibiotic drugs is creation of analogues of natural protective molecules that provide a host defense against pathogenic bacteria, in particular analogues of antimicrobial peptides of the innate immune system. The aim of our work was design, chemical synthesis and characterization of antimicrobial and hemolytic activity of a peptide protegrin 1 (PG1) structural variants. Three analogues of PG1 were produced and studied, it was shown that two PG1 variants exhibit a high activity against antibiotic-resistant bacteria. A comparative analysis of the hemolytic activity of the peptides towards human erythrocytes was carried out. The ways of further work directed to creation of novel antimicrobials based on a natural peptide PG1 for combating drug-resistant bacteria are outlined.

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Ibrahim, Mariam, Alain Guillot, Francoise Wessner, Florence Algaron, Colette Besset, Pascal Courtin, Rozenn Gardan, and Véronique Monnet. "Control of the Transcription of a Short Gene Encoding a Cyclic Peptide in Streptococcus thermophilus: a New Quorum-Sensing System?" Journal of Bacteriology 189, no. 24 (October 5, 2007): 8844–54. http://dx.doi.org/10.1128/jb.01057-07.

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ABSTRACT Gram-positive bacteria secrete a variety of peptides that are often subjected to posttranslational modifications and that are either antimicrobials or pheromones involved in bacterial communication. Our objective was to identify peptides secreted by Streptococcus thermophilus, a nonpathogenic bacterium widely used in dairy technology in association with other bacteria, and to understand their potential roles in cell-cell communication. Using reverse-phase liquid chromatography, mass spectrometry, and Edman sequencing, we analyzed the culture supernatants of three S. thermophilus strains (CNRZ1066, LMG18311, and LMD-9) grown in a medium containing no peptides. We identified several peptides in the culture supernatants, some of them found with the three strains while others were specific to the LMD-9 strain. We focused our study on a new modified peptide secreted by S. thermophilus LMD-9 and designated Pep1357C. This peptide contains 9 amino acids and lost 2 Da in a posttranslational modification, most probably a dehydrogenation, leading to a linkage between the Lys2 and Trp6 residues. Production of Pep1357C and transcription of its encoding gene depend on both the medium composition and the growth phase. Furthermore, we demonstrated that transcription of the gene coding for Pep1357C is drastically decreased in mutants inactivated for the synthesis of a short hydrophobic peptide, a transcriptional regulator, or the oligopeptide transport system. Taken together, our results led us to deduce that the transcription of the Pep1357C-encoding gene is controlled by a new quorum-sensing system.

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Raj, Periathamby Antony, Latha Rajkumar, and Andrew R. Dentino. "Novel molecules for intra-oral delivery of antimicrobials to prevent and treat oral infectious diseases." Biochemical Journal 409, no. 2 (December 21, 2007): 601–9. http://dx.doi.org/10.1042/bj20070810.

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New molecules were designed for efficient intra-oral delivery of antimicrobials to prevent and treat oral infection. The salivary statherin fragment, which has high affinity for the tooth enamel, was used as a carrier peptide. This was linked through the side chain of the N-terminal residue to the C-terminus of a defensin-like 12-residue peptide to generate two bifunctional hybrid molecules, one with an ester linkage and the other with an anhydride bond between the carrier and the antimicrobial components. They were examined for their affinity to a HAP (hydroxyapatite) surface. The extent of the antimicrobial release in human whole saliva was determined using 13C-NMR spectroscopy. The candidacidal activity of the molecules was determined as a function of the antimicrobial release from the carrier peptide in human saliva. The hybrid-adsorbed HAP surface was examined against Candida albicans and Aggregatibacter actinomycetemcomitans using the fluorescence technique. The bifunctional molecules were tested on human erythrocytes, GECs (gingival epithelial cells) and GFCs (gingival fibroblast cells) for cytotoxicity. They were found to possess high affinity for the HAP mineral. In human whole saliva, a sustained antimicrobial release over a period of more than 40–60 h, and candidacidal activity consistent with the extent of hybrid dissociation were observed. Moreover, the bifunctional peptide-bound HAP surface was found to exhibit antimicrobial activity when suspended in clarified human saliva. The hybrid peptides did not show any toxic influence on human erythrocytes, GECs and GFCs. These novel hybrids could be safely used to deliver therapeutic agents intra-orally for the treatment and prevention of oral infectious diseases.

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Mishra, Biswajit, Jayaram Lakshmaiah Narayana, Tamara Lushnikova, Yingxia Zhang, Radha M. Golla, D. Zarena, and Guangshun Wang. "Sequence Permutation Generates Peptides with Different Antimicrobial and Antibiofilm Activities." Pharmaceuticals 13, no. 10 (September 25, 2020): 271. http://dx.doi.org/10.3390/ph13100271.

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Antibiotic resistance poses a threat to our society, and 10 million people could die by 2050. To design potent antimicrobials, we made use of the antimicrobial peptide database (APD). Using the database filtering technology, we identified a useful template and converted it into an effective peptide WW291 against methicillin-resistant Staphylococcus aureus (MRSA). Here, we compared the antibacterial activity and cytotoxicity of a family of peptides obtained from sequence permutation of WW291. The resulting eight WW peptides (WW291-WW298) gained different activities against a panel of bacteria. While WW295 inhibited the growth of Escherichia coli, WW298 was highly active against S. aureus USA300 LAC. Consistently with this, WW298 was more effective in permeating or depolarizing the S. aureus membranes, whereas WW295 potently permeated the E. coli membranes. In addition, WW298, but not WW295, inhibited the MRSA attachment and could disrupt its preformed biofilms more effectively than daptomycin. WW298 also protected wax moths Galleria mellonella from MRSA infection causing death. Thus, sequence permutation provides one useful avenue to generating antimicrobial peptides with varying activity spectra. Taken together with amino acid composition modulation, these methods may lead to narrow-spectrum peptides that are more promising to selectively eliminate invading pathogens without damaging commensal microbiota.

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Walkenhorst, William F., J. Wolfgang Klein, Phuong Vo, and William C. Wimley. "pH Dependence of Microbe Sterilization by Cationic Antimicrobial Peptides." Antimicrobial Agents and Chemotherapy 57, no. 7 (May 6, 2013): 3312–20. http://dx.doi.org/10.1128/aac.00063-13.

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ABSTRACTWe recently described a family of cationic antimicrobial peptides (CAMPs) selected from a combinatorial library that exhibited potent, broad-spectrum activity at neutral pH and low ionic strength. To further delimit the utility and activity profiles of these peptides, we investigated the effects of solution conditions, such as pH and ionic strength, on the efficacy of the peptide antimicrobials against a panel of microorganisms. Peptide minimum sterilizing concentrations (MSCs) varied linearly with pH for each subtype within our family of CAMPs for all organisms tested. The peptides were much less effective against Gram-negative bacteria at high pH, consistent with a decrease in net positive charge on the peptides. A similar trend was observed for the fungusCandida albicans. Surprisingly, the opposite pH trend was observed with the Gram-positiveStaphylococcus aureus. In addition, an additive ionic strength effect was observed with increasing buffer strengths at identical pH values. The extreme difference in the observed pH behavior between Gram-negative and Gram-positive organisms is attributed to the presence of native charged molecules in the much thicker peptidoglycan layer of the Gram-positive organism. The novel species-specific effects of pH observed here have important implications for applications using CAMPs and for the design of novel CAMPs.

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Wu, Chih-Lung, Ju-Yun Hsueh, Bak-Sau Yip, Ya-Han Chih, Kuang-Li Peng, and Jya-Wei Cheng. "Antimicrobial Peptides Display Strong Synergy with Vancomycin Against Vancomycin-Resistant E. faecium, S. aureus, and Wild-Type E. coli." International Journal of Molecular Sciences 21, no. 13 (June 27, 2020): 4578. http://dx.doi.org/10.3390/ijms21134578.

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There is an urgent and imminent need to develop new antimicrobials to fight against antibiotic-resistant bacterial and fungal strains. In this study, a checkerboard method was used to evaluate the synergistic effects of the antimicrobial peptide P-113 and its bulky non-nature amino acid substituted derivatives with vancomycin against vancomycin-resistant Enterococcus faecium, Staphylococcus aureus, and wild-type Escherichia coli. Boron-dipyrro-methene (BODIPY) labeled vancomycin was used to characterize the interactions between the peptides, vancomycin, and bacterial strains. Moreover, neutralization of antibiotic-induced releasing of lipopolysaccharide (LPS) from E. coli by the peptides was obtained. Among these peptides, Bip-P-113 demonstrated the best minimal inhibitory concentrations (MICs), antibiotics synergism, bacterial membrane permeabilization, and supernatant LPS neutralizing activities against the bacteria studied. These results could help in developing antimicrobial peptides that have synergistic activity with large size glycopeptides such as vancomycin in therapeutic applications.

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Reymond, Jean-Louis. "Peptide Dendrimers: From Enzyme Models to Antimicrobials and Transfection Reagents." CHIMIA International Journal for Chemistry 75, no. 6 (June 30, 2021): 535–38. http://dx.doi.org/10.2533/chimia.2021.535.

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Aiming at studying cooperativity effects between amino acids in easily accessible protein models, we have explored the chemistry of peptide dendrimers, which we obtain as pure products by solid-phase peptide synthesis using a branching diamino acid such as lysine at every second or third position in a peptide sequence, followed by reverse-phase HPLC purification. This article reviews discoveries driven by combinatorial library synthesis and screening, including enantioselective esterase and aldolase enzyme models, cobalamin binding and peroxidase dendrimers, glycopeptide dendrimer biofilm inhibitors and their X-ray crystal structures as complexes with lectins, antimicrobial peptide dendrimers active against multidrug resistant Gram-negative bacteria, and transfection reagents for siRNA and CRISPR-Cas9 plasmid DNA. Latest developments include cheminformatics and artificial intelligence for exploring the peptide chemical space, and the principle of stereorandomization to understand the role of peptide chirality in activity.

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Taale, Essodolom, Aly Savadogo, Cheikna Zongo, François Tapsoba, Simplice D. Karou, and Alfred S. Traore. "Les peptides antimicrobiens d’origine microbienne: cas des bactériocines." International Journal of Biological and Chemical Sciences 10, no. 1 (August 8, 2016): 384. http://dx.doi.org/10.4314/ijbcs.v10i1.29.

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Basi-Chipalu, Shradha. "A Review: Lantibiotics, a Promising Antimicrobial Agent." Journal of Institute of Science and Technology 21, no. 1 (November 24, 2016): 119–28. http://dx.doi.org/10.3126/jist.v21i1.16063.

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Rise in multi drug resistant bacteria has been a public health problem. This has necessitated for the exploration of novel antimicrobials. Bacteriocins, probiotic bacteria, and bacteriophages are considered as alternatives to antibiotics. To this context, lantibiotics could be the future candidate for antimicrobial agent.Lantibiotics are synthesized ribosomally and after posttranslational modification active peptide is produced.Lantibiotics are lanthionine and methyllanthionine containing peptides exhibiting activity against multi drug resistant pathogens. Besides its application as alternatives to old antibiotics, they can be used as food preservatives, additives, probiotics, and prophylactics.Journal of Institute of Science and TechnologyVolume 21, Issue 1, August 2016, Page: 119-128

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del Villar Pérez, Víctor Manuel, Alberto Barreras Serrano, Lourdes Carolina Pujol Manríquez, Luis Tinoco Gracia, Tonatiuh Melgarejo, and Alma Rossana Tamayo Sosa. "Expression of b-defensins LAP (lingual antimicrobial peptide) and TAP (antimicrobial peptide tracheal), and Psoriasin (S100A7), in bovine mammary gland with chronic mastitis by Staphylococcus aureus." Acta Universitaria 26, no. 4 (September 2016): 29–35. http://dx.doi.org/10.15174/au.2016.930.

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Cunsolo, Vincenzo, Rosario Schicchi, Marco Chiaramonte, Luigi Inguglia, Vincenzo Arizza, Maria Grazia Cusimano, Domenico Schillaci, et al. "Identification of New Antimicrobial Peptides from Mediterranean Medical Plant Charybdis pancration (Steinh.) Speta." Antibiotics 9, no. 11 (October 28, 2020): 747. http://dx.doi.org/10.3390/antibiotics9110747.

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The present work was designed to identify and characterize novel antimicrobial peptides (AMPs) from Charybdis pancration (Steinh.) Speta, previously named Urginea maritima, is a Mediterranean plant, well-known for its biological properties in traditional medicine. Polypeptide-enriched extracts from different parts of the plant (roots, leaves and bulb), never studied before, were tested against two relevant pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. With the aim of identifying novel natural AMPs, peptide fraction displaying antimicrobial activity (the bulb) that showed minimum inhibitory concentration (MICs) equal to 30 µg/mL against the above mentioned strains, was analysed by high-resolution mass spectrometry and database search. Seventeen peptides, related to seven proteins present in the investigated database, were described. Furthermore, we focused on three peptides, which due to their net positive charge, have a better chance to be AMPs and they were investigated by molecular modelling approaches, in order to shed light on the solution properties of their equilibrium structures. Some of new detected peptides could represent a good platform for the development of new antimicrobials in the fight against antibiotic resistance phenomenon.

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Spinello, Angelo, Maria Cusimano, Domenico Schillaci, Luigi Inguglia, Giampaolo Barone, and Vincenzo Arizza. "Antimicrobial and Antibiofilm Activity of a Recombinant Fragment of β-Thymosin of Sea Urchin Paracentrotus lividus." Marine Drugs 16, no. 10 (October 2, 2018): 366. http://dx.doi.org/10.3390/md16100366.

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With the aim to obtain new antimicrobials against important pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa, we focused on antimicrobial peptides (AMPs) from Echinoderms. An example of such peptides is Paracentrin 1 (SP1), a chemically synthesised peptide fragment of a sea urchin thymosin. In the present paper, we report on the biological activity of a Paracentrin 1 derivative obtained by recombination. The recombinant paracentrin RP1, in comparison to the synthetic SP1, is 22 amino acids longer and it was considerably more active against the planktonic forms of S. aureus ATCC 25923 and P. aeruginosa ATCC 15442 at concentrations of 50 µg/mL. Moreover, it was able to inhibit biofilm formation of staphylococcal and P. aeruginosa strains at concentrations equal to 5.0 and 10.7 µg/mL, respectively. Molecular dynamics (MD) simulations allowed to rationalise the results of the experimental investigations, providing atomistic insights on the binding of RP1 toward models of mammalian and bacterial cell membranes. Overall, the results obtained point out that RP1 shows a remarkable preference for bacterial membranes, in excellent agreement with the antibacterial activity, highlighting the promising potential of using the tested peptide as a template for the development of novel antimicrobial agents.

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Vila-Farres, Xavier, John Chu, Daigo Inoyama, Melinda A. Ternei, Christophe Lemetre, Louis J. Cohen, Wooyoung Cho, et al. "Antimicrobials Inspired by Nonribosomal Peptide Synthetase Gene Clusters." Journal of the American Chemical Society 139, no. 4 (January 23, 2017): 1404–7. http://dx.doi.org/10.1021/jacs.6b11861.

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Hazam, Prakash Kishore, Ruchika Goyal, and Vibin Ramakrishnan. "Peptide based antimicrobials: Design strategies and therapeutic potential." Progress in Biophysics and Molecular Biology 142 (March 2019): 10–22. http://dx.doi.org/10.1016/j.pbiomolbio.2018.08.006.

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Yount, Nannette Y., and Michael R. Yeaman. "Peptide antimicrobials: cell wall as a bacterial target." Annals of the New York Academy of Sciences 1277, no. 1 (January 2013): 127–38. http://dx.doi.org/10.1111/nyas.12005.

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Kourie, J. I., and A. A. Shorthouse. "Properties of cytotoxic peptide-formed ion channels." American Journal of Physiology-Cell Physiology 278, no. 6 (June 1, 2000): C1063—C1087. http://dx.doi.org/10.1152/ajpcell.2000.278.6.c1063.

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Cytotoxic peptides are relatively small cationic molecules such as those found 1) in venoms, e.g., melittin in bee, scorpion toxins in scorpion, pilosulin 1 in jumper ant, and lycotoxin I and II in wolf spider; 2) in skin secretions (e.g., magainin I and II from Xenopus laevis, dermaseptin from frog, antimicrobials from carp) and cells of the immune system (e.g., insect, scorpion, and mammalian defensins and cryptdins); 3) as autocytotoxicity peptides, e.g., amylin cytotoxic to pancreatic β-cells, prion peptide fragment 106–126 [PrP-(106–126)], and amyloid β-protein (AβP) cytotoxic to neurons; and 4) as designed synthetic peptides based on the sequences and properties of naturally occurring cytotoxic peptides. The small cytotoxic peptides are composed of β-sheets, e.g., mammalian defensins, AβP, amylin, and PrP-(106–126), whereas the larger cytotoxic peptides have several domains composed of both α-helices and β-sheets stabilized by cysteine bonds, e.g., scorpion toxins, scorpion, and insect defensins. Electrophysiological and molecular biology techniques indicate that these structures modify cell membranes via 1) interaction with intrinsic ion transport proteins and/or 2) formation of ion channels. These two nonexclusive mechanisms of action lead to changes in second messenger systems that further augment the abnormal electrical activity and distortion of the signal transduction causing cell death.

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Vossier, L., F. Leon, J. Coste, and C. Fournier-Wirth. "Production de peptides antimicrobiens naturels actifs par recyclage biologique." Transfusion Clinique et Biologique 20, no. 3 (June 2013): 309–10. http://dx.doi.org/10.1016/j.tracli.2013.03.061.

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Nüsslein, Klaus, Lachelle Arnt, Jason Rennie, Cullen Owens, and Gregory N. Tew. "Broad-spectrum antibacterial activity by a novel abiogenic peptide mimic." Microbiology 152, no. 7 (July 1, 2006): 1913–18. http://dx.doi.org/10.1099/mic.0.28812-0.

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The human-mediated use and abuse of classical antibiotics has created a strong selective pressure for the rapid evolution of antibiotic resistance. As resistance levels rise, and the efficacy of classical antibiotics wanes, the intensity of the search for alternative antimicrobials has increased. One class of molecules that has attracted much attention is the antimicrobial peptides (AMPs). They exhibit broad-spectrum activity, they are potent and they are widespread as part of the innate defence system of both vertebrates and invertebrates. However, peptides are complex molecules that suffer from proteolytic degradation. The ability to capture the essential properties of antimicrobial peptides in simple easy-to-prepare molecules that are abiotic in origin and non-proteolytic offers many advantages. Mechanistic and structural knowledge of existing AMPs was used to design a novel compound that mimics the biochemical activity of an AMP. This report describes the development and in vitro characterization of a small peptide mimic that exhibited quick-acting and selective antibacterial activity against a broad range of bacteria, including numerous clinically relevant strains, at low MIC values.

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Locock, Katherine E. S. "Bioinspired Polymers: Antimicrobial Polymethacrylates." Australian Journal of Chemistry 69, no. 7 (2016): 717. http://dx.doi.org/10.1071/ch16047.

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Naturally occurring antimicrobial peptides have been honed by evolution over millions of years to give highly safe and efficacious antimicrobials that form part of many organisms’ immune systems. By studying these peptides to identify key aspects of structure and composition, suitable synthetic polymer mimics can be designed that hold potential as anti-infective agents. This review focusses on an important aspect of peptide mimicry, that of replicating the chemical functionality provided by key amino acids present in antimicrobial peptides. These include polymethacrylate mimics of arginine-rich and tryptophan-rich peptides. Systematic investigation of the structure–activity relationships of these polymers identifies the guanidine based poly(methylmethacrylate-co-2-guanidinoethyl methacrylate) (pMMA-co-GEMA) copolymers with low molecular weight and low methyl content as having superior activity profiles when compared with all other combinations. Unique antibiofilm activity of these polymers is also revealed in in vitro testing against monomicrobial and polymicrobial biofilms of the bacteria Staphylococcus aureus and the fungus Candida albicans. This highlights Mother Nature as an important resource in drug development and identifies the arginine-mimicking polymethacrylates as important leads for the development of a new generation of antimicrobial agents to tackle resistance.

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Kuppusamy, Willcox, Black, and Kumar. "Short Cationic Peptidomimetic Antimicrobials." Antibiotics 8, no. 2 (April 18, 2019): 44. http://dx.doi.org/10.3390/antibiotics8020044.

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The rapid growth of antimicrobial resistance against several frontline antibiotics has encouraged scientists worldwide to develop new alternatives with unique mechanisms of action. Antimicrobial peptides (AMPs) have attracted considerable interest due to their rapid killing and broad-spectrum activity. Peptidomimetics overcome some of the obstacles of AMPs such as high cost of synthesis, short half-life in vivo due to their susceptibility to proteolytic degradation, and issues with toxicity. This review will examine the development of short cationic peptidomimetics as antimicrobials.

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van Harten, Roel, Esther van Woudenbergh, Albert van Dijk, and Henk Haagsman. "Cathelicidins: Immunomodulatory Antimicrobials." Vaccines 6, no. 3 (September 14, 2018): 63. http://dx.doi.org/10.3390/vaccines6030063.

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Cathelicidins are host defense peptides with antimicrobial and immunomodulatory functions. These effector molecules of the innate immune system of many vertebrates are diverse in their amino acid sequence but share physicochemical characteristics like positive charge and amphipathicity. Besides being antimicrobial, cathelicidins have a wide variety in immunomodulatory functions, both boosting and inhibiting inflammation, directing chemotaxis, and effecting cell differentiation, primarily towards type 1 immune responses. In this review, we will examine the biology and various functions of cathelicidins, focusing on putting in vitro results in the context of in vivo situations. The pro-inflammatory and anti-inflammatory functions are highlighted, as well both direct and indirect effects on chemotaxis and cell differentiation. Additionally, we will discuss the potential and limitations of using cathelicidins as immunomodulatory or antimicrobial drugs.

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Rodríguez, J. M. "Revisión: Espectro antimicrobiano, estructura, propiedades y mode de acción de la nisina, una bacteriocina producida por Lactococcus lactis/Review: Antimicrobial spectrum, structure, properties and mode of action of nisin, a bacteriocin produced by Lactococcus lactis." Food Science and Technology International 2, no. 2 (April 1996): 61–68. http://dx.doi.org/10.1177/108201329600200202.

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Nisin is a 34 amino acid antibacterial peptide produced by certain strains of Lactococcus lactis. This bacteriocin has found wide application as a food preservative owing to its non-toxic nature, its heat stability at acidic pH, its inactivation by proteolytic enzymes in the digestive tract and, especially, to its antimicrobial activity against a broad range of Gram-positive organisms, including food pathogens of concern in food industry such as Clostridium botulinum and Listeria monocytogenes. However, the use of nisin has the limitation that its solubility and stability decrease progressively as the environ mental pH increases. The two natural variants of nisin, named nisin A and nisin Z, are ribosomally synthesized as 57 amino acid precursor peptides which are subjected to further modifications. The mature peptide displays several unusual features, such as the presence of dehydrated amino acids and lanthionine rings. Insertion of the peptide into the cytoplasmic membrane of susceptible cells leads to the formation of pores, dissipating the membrane potential and pH gradients.

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Rydlo, Tali, Shahar Rotem, and Amram Mor. "Antibacterial Properties of Dermaseptin S4 Derivatives under Extreme Incubation Conditions." Antimicrobial Agents and Chemotherapy 50, no. 2 (February 2006): 490–97. http://dx.doi.org/10.1128/aac.50.2.490-497.2006.

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ABSTRACT Antibacterial properties of the frog-derived peptide dermaseptin S4 and a series of synthetic derivatives against the food pathogen Escherichia coli O157:H7 were investigated under extreme incubation conditions. The 28-mer analog K4K20S4 (P28) displayed an MIC of 8 μM and rapid bactericidal kinetics under standard culture conditions. Potent bactericidal properties were maintained at high salt concentrations, under acidic or basic conditions, and at extreme temperatures. The N-terminal 14-mer sequence (P14) displayed higher potency (MIC, 4 μM) but only within a narrow range of incubation conditions, pointing to the importance of the C-terminal domain of P28. The potency range was reextended upon conjugation of aminododecanoic acid to P14. The resulting lipopeptide was even more potent (MIC, 2 μM) and affected bacterial viability under most of the conditions tested, including in commercial apple juice. The mechanistic implications of peptides' hydrophobicity, charge, structure, and binding to an idealized membrane were probed and are discussed here. Collectively, the data indicate interest in simple peptide-based compounds for design of antimicrobials that affect pathogens under a variable range of incubation conditions.

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Green, R. Madison, and Kevin L. Bicker. "Evaluation of peptoid mimics of short, lipophilic peptide antimicrobials." International Journal of Antimicrobial Agents 56, no. 2 (August 2020): 106048. http://dx.doi.org/10.1016/j.ijantimicag.2020.106048.

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Hashemi, Marjan, Augusta Mmuoegbulam, Brett Holden, Jordan Coburn, John Wilson, Maddison Taylor, Joseph Reiley, et al. "Susceptibility of Multidrug-Resistant Bacteria, Isolated from Water and Plants in Nigeria, to Ceragenins." International Journal of Environmental Research and Public Health 15, no. 12 (December 6, 2018): 2758. http://dx.doi.org/10.3390/ijerph15122758.

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The continuous emergence of multidrug resistant pathogens is a major global health concern. Although antimicrobial peptides (AMPs) have shown promise as a possible means of combatting multidrug resistant strains without readily engendering resistance, costs of production and targeting by proteases limit their utility. Ceragenins are non-peptide AMP mimics that overcome these shortcomings while retaining broad-spectrum antimicrobial activity. To further characterize the antibacterial activities of ceragenins, their activities against a collection of environmental isolates of bacteria were determined. These isolates were isolated in Nigeria from plants and water. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of selected ceragenins and currently available antimicrobials against these isolates were measured to determine resistance patterns. Using scanning electron microscopy (SEM), we examined the morphological changes in bacterial membranes following treatment with ceragenins. Finally, we investigated the effectiveness of ceragenins in inhibiting biofilm formation and destroying established biofilms. We found that, despite high resistance to many currently available antimicrobials, including colistin, environmental isolates in planktonic and biofilm forms remain susceptible to ceragenins. Additionally, SEM and confocal images of ceragenin-treated cells confirmed the effective antibacterial and antibiofilm activity of ceragenins.

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Deslouches, Berthony, Kazi Islam, Jodi K. Craigo, Shruti M. Paranjape, Ronald C. Montelaro, and Timothy A. Mietzner. "Activity of the De Novo Engineered Antimicrobial Peptide WLBU2 against Pseudomonas aeruginosa in Human Serum and Whole Blood: Implications for Systemic Applications." Antimicrobial Agents and Chemotherapy 49, no. 8 (August 2005): 3208–16. http://dx.doi.org/10.1128/aac.49.8.3208-3216.2005.

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ABSTRACT Cationic amphipathic peptides have been extensively investigated as a potential source of new antimicrobials that can complement current antibiotic regimens in the face of emerging drug-resistant bacteria. However, the suppression of antimicrobial activity under certain biologically relevant conditions (e.g., serum and physiological salt concentrations) has hampered efforts to develop safe and effective antimicrobial peptides for clinical use. We have analyzed the activity and selectivity of the human peptide LL37 and the de novo engineered antimicrobial peptide WLBU2 in several biologically relevant conditions. The host-derived synthetic peptide LL37 displayed high activity against Pseudomonas aeruginosa but demonstrated staphylococcus-specific sensitivity to NaCl concentrations varying from 50 to 300 mM. Moreover, LL37 potency was variably suppressed in the presence of 1 to 6 mM Mg2+ and Ca2+ ions. In contrast, WLBU2 maintained its activity in NaCl and physiologic serum concentrations of Mg2+ and Ca2+. WLBU2 is able to kill P. aeruginosa (106 CFU/ml) in human serum, with a minimum bactericidal concentration of <9 μM. Conversely, LL37 is inactive in the presence of human serum. Bacterial killing kinetic assays in serum revealed that WLBU2 achieved complete bacterial killing in 20 min. Consistent with these results was the ability of WLBU2 (15 to 20 μM) to eradicate bacteria from ex vivo samples of whole blood. The selectivity of WLBU2 was further demonstrated by its ability to specifically eliminate P. aeruginosa in coculture with human monocytes or skin fibroblasts without detectable adverse effects to the host cells. Finally, WLBU2 displayed potent efficacy against P. aeruginosa in an intraperitoneal infection model using female Swiss Webster mice. These results establish a potential application of WLBU2 in the treatment of bacterial sepsis.

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Drago-Serrano, Maria Elisa, Rafael Campos-Rodriguez, Julio Cesar Carrero, and Mireya de la Garza. "Lactoferrin and Peptide-derivatives: Antimicrobial Agents with Potential Use in Nonspecific Immunity Modulation." Current Pharmaceutical Design 24, no. 10 (May 28, 2018): 1067–78. http://dx.doi.org/10.2174/1381612824666180327155929.

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Lactoferrin (Lf) is a conserved cationic non-heme glycoprotein that is part of the innate immune defense system of mammals. Lf is present in colostrum, milk and mucosal sites, and it is also produced by polymorphonuclear neutrophils and secreted at infection sites. Lf and Lf N-terminus peptide-derivatives named lactoferricins (Lfcins) are molecules with microbiostatic and microbicidal action in a wide array of pathogens. In addition, they display regulatory properties on components of nonspecific immunity, including toll-like receptors, proand anti-inflammatory cytokines, and reactive oxygen species. Mechanisms explaining the ability of Lf and Lfcins to display both up- and down-modulatory properties on cells are not fully understood but result, in part, from their interactions with membrane receptors that elicit biochemical signal pathways, whereas other receptors enable the nuclear translocation of these molecules for the modulation of target genes. The dual role of Lf and Lfcins as antimicrobials and immunomodulators is of biotechnological and pharmaceutical interest. Native Lf and its peptide-derivatives from human and bovine sources, the recombinant versions of the human protein, and their synthetic peptides have potential application as adjunctive agents in therapies to combat infections caused by multi-resistant bacteria and those caused by fungi, protozoa and viruses, as well as in the prevention and reduction of several types of cancer and response to LPS-shock, among other effects. In this review, we summarize the immunomodulatory properties of the unique multifunctional protein Lf and its N-terminus peptides.

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Nicolas, P., A. Mor, and A. Delfour. "Les peptides de la défense antimicrobienne des vertébrés." médecine/sciences 8, no. 5 (1992): 423. http://dx.doi.org/10.4267/10608/3158.

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Weiman, Shannon. "Promising Antimicrobials: Synthetic Molecules Based on Defensin Peptides." Microbe Magazine 8, no. 1 (January 1, 2013): 9–10. http://dx.doi.org/10.1128/microbe.8.9.1.

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Journal articles on the topic 'Peptide antimicrobiens'

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