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Sample records for antimicrobial peptide derived

  1. Antimicrobial activity of human salivary mucin-derived peptides

    NARCIS (Netherlands)

    Wei, G.

    2008-01-01

    We investigated: a) relationships between molecular properties and antimicrobial functions of MUC7 peptides, b) effects of host physiological factors on the antimicrobial activity of MUC7 peptides, c) enhancement of antifungal activity by combination of MUC7 peptides with EDTA or other agents, d) an

  2. Highly selective end-tagged antimicrobial peptides derived from PRELP.

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    Martin Malmsten

    Full Text Available BACKGROUND: Antimicrobial peptides (AMPs are receiving increasing attention due to resistance development against conventional antibiotics. Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in an array of infections such as ocular infections, cystic fibrosis, wound and post-surgery infections, and sepsis. The goal of the study was to design novel AMPs against these pathogens. METHODOLOGY AND PRINCIPAL FINDINGS: Antibacterial activity was determined by radial diffusion, viable count, and minimal inhibitory concentration assays, while toxicity was evaluated by hemolysis and effects on human epithelial cells. Liposome and fluorescence studies provided mechanistic information. Protease sensitivity was evaluated after subjection to human leukocyte elastase, staphylococcal aureolysin and V8 proteinase, as well as P. aeruginosa elastase. Highly active peptides were evaluated in ex vivo skin infection models. C-terminal end-tagging by W and F amino acid residues increased antimicrobial potency of the peptide sequences GRRPRPRPRP and RRPRPRPRP, derived from proline arginine-rich and leucine-rich repeat protein (PRELP. The optimized peptides were antimicrobial against a range of gram-positive S. aureus and gram-negative P. aeruginosa clinical isolates, also in the presence of human plasma and blood. Simultaneously, they showed low toxicity against mammalian cells. Particularly W-tagged peptides displayed stability against P. aeruginosa elastase, and S. aureus V8 proteinase and aureolysin, and the peptide RRPRPRPRPWWWW-NH(2 was effective against various "superbugs" including vancomycin-resistant enterococci, multi-drug resistant P. aeruginosa, and methicillin-resistant S. aureus, as well as demonstrated efficiency in an ex vivo skin wound model of S. aureus and P. aeruginosa infection. CONCLUSIONS/SIGNIFICANCE: Hydrophobic C-terminal end-tagging of the cationic sequence RRPRPRPRP generates highly selective AMPs with potent

  3. Antimicrobial Peptides

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    Ali Adem Bahar

    2013-11-01

    Full Text Available The rapid increase in drug-resistant infections has presented a serious challenge to antimicrobial therapies. The failure of the most potent antibiotics to kill “superbugs” emphasizes the urgent need to develop other control agents. Here we review the history and new development of antimicrobial peptides (AMPs, a growing class of natural and synthetic peptides with a wide spectrum of targets including viruses, bacteria, fungi, and parasites. We summarize the major types of AMPs, their modes of action, and the common mechanisms of AMP resistance. In addition, we discuss the principles for designing effective AMPs and the potential of using AMPs to control biofilms (multicellular structures of bacteria embedded in extracellular matrixes and persister cells (dormant phenotypic variants of bacterial cells that are highly tolerant to antibiotics.

  4. The antimicrobial peptides derived from chromogranin/secretogranin family, new actors of innate immunity.

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    Shooshtarizadeh, Peiman; Zhang, Dan; Chich, Jean-François; Gasnier, Claire; Schneider, Francis; Haïkel, Youssef; Aunis, Dominique; Metz-Boutigue, Marie-Hélène

    2010-11-30

    Chromogranins/secretogranins are members of the granin family present in secretory vesicles of nervous, endocrine and immune cells. In chromaffin cells, activation of nicotinic cholinergic receptors induces the release, with catecholamines, of bioactive peptides resulting from a natural processing. During the past decade, our laboratory has characterized new antimicrobial chromogranin-derived peptides in the secretions of stimulated bovine chromaffin cells. They act at the micromolar range against bacteria, fungi, yeasts, and are non-toxic for the mammalian cells. They are recovered in several biological fluids involved in defence mechanisms (human serum, neutrophil secretions and saliva). These new antimicrobial peptides demonstrate the major role of the adrenal medulla in innate immunity. In this review we focus on the antimicrobial peptides derived from human and bovine chromogranin A (CGA), chromogranin B (CGB) and secretogranin II (SGII) emphasizing their direct action against pathogens and their effects on immune cells.

  5. Antimicrobial peptides.

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    Zhang, Ling-Juan; Gallo, Richard L

    2016-01-11

    Antimicrobial peptides and proteins (AMPs) are a diverse class of naturally occurring molecules that are produced as a first line of defense by all multicellular organisms. These proteins can have broad activity to directly kill bacteria, yeasts, fungi, viruses and even cancer cells. Insects and plants primarily deploy AMPs as an antibiotic to protect against potential pathogenic microbes, but microbes also produce AMPs to defend their environmental niche. In higher eukaryotic organisms, AMPs can also be referred to as 'host defense peptides', emphasizing their additional immunomodulatory activities. These activities are diverse, specific to the type of AMP, and include a variety of cytokine and growth factor-like effects that are relevant to normal immune homeostasis. In some instances, the inappropriate expression of AMPs can also induce autoimmune diseases, thus further highlighting the importance of understanding these molecules and their complex activities. This Primer will provide an update of our current understanding of AMPs. PMID:26766224

  6. Antimicrobial properties of two novel peptides derived from Theobroma cacao osmotin.

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    Falcao, Loeni L; Silva-Werneck, Joseilde O; Ramos, Alessandra de R; Martins, Natalia F; Bresso, Emmanuel; Rodrigues, Magali A; Bemquerer, Marcelo P; Marcellino, Lucilia H

    2016-05-01

    The osmotin proteins of several plants display antifungal activity, which can play an important role in plant defense against diseases. Thus, this protein can be useful as a source for biotechnological strategies aiming to combat fungal diseases. In this work, we analyzed the antifungal activity of a cacao osmotin-like protein (TcOsm1) and of two osmotin-derived synthetic peptides with antimicrobial features, differing by five amino acids residues at the N-terminus. Antimicrobial tests showed that TcOsm1 expressed in Escherichia coli inhibits the growth of Moniliophthora perniciosa mycelium and Pichia pastoris X-33 in vitro. The TcOsm1-derived peptides, named Osm-pepA (H-RRLDRGGVWNLNVNPGTTGARVWARTK-NH2), located at R23-K49, and Osm-pepB (H-GGVWNLNVNPGTTGARVWARTK-NH2), located at G28-K49, inhibited growth of yeasts (Saccharomyces cerevisiae S288C and Pichia pastoris X-33) and spore germination of the phytopathogenic fungi Fusarium f. sp. glycines and Colletotrichum gossypi. Osm-pepA was more efficient than Osm-pepB for S. cerevisiae (MIC=40μM and MIC=127μM, respectively), as well as for P. pastoris (MIC=20μM and MIC=127μM, respectively). Furthermore, the peptides presented a biphasic performance, promoting S. cerevisiae growth in doses around 5μM and inhibiting it at higher doses. The structural model for these peptides showed that the five amino acids residues, RRLDR at Osm-pepA N-terminus, significantly affect the tertiary structure, indicating that this structure is important for the peptide antimicrobial potency. This is the first report of development of antimicrobial peptides from T. cacao. Taken together, the results indicate that the cacao osmotin and its derived peptides, herein studied, are good candidates for developing biotechnological tools aiming to control phytopathogenic fungi. PMID:26996966

  7. Chemokine-Derived Peptides: Novel Antimicrobial and Antineoplasic Agents

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    Valdivia-Silva, Julio; Medina-Tamayo, Jaciel; Garcia-Zepeda, Eduardo A.

    2015-01-01

    Chemokines are a burgeoning family of chemotactic cytokines displaying a broad array of functions such as regulation of homeostatic leukocyte traffic and development, as well as activating the innate immune system. Their role in controlling early and late inflammatory stages is now well recognized. An improper balance either in chemokine synthesis or chemokine receptor expression contributes to various pathological disorders making chemokines and their receptors a useful therapeutic target. Research in this area is progressing rapidly, and development of novel agents based on chemokine/chemokine receptors antagonist functions are emerging as attractive alternative drugs. Some of these novel agents include generation of chemokine-derived peptides (CDP) with potential agonist and antagonist effects on inflammation, cancer and against bacterial infections. CDP have been generated mainly from N- and C-terminus chemokine sequences with subsequent modifications such as truncations or elongations. In this review, we present a glimpse of the different pharmacological actions reported for CDP and our current understanding regarding the potential use of CDP alone or as part of the novel therapies proposed in the treatment of microbial infections and cancer. PMID:26062132

  8. Chemokine-Derived Peptides: Novel Antimicrobial and Antineoplasic Agents

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    Julio Valdivia-Silva

    2015-06-01

    Full Text Available Chemokines are a burgeoning family of chemotactic cytokines displaying a broad array of functions such as regulation of homeostatic leukocyte traffic and development, as well as activating the innate immune system. Their role in controlling early and late inflammatory stages is now well recognized. An improper balance either in chemokine synthesis or chemokine receptor expression contributes to various pathological disorders making chemokines and their receptors a useful therapeutic target. Research in this area is progressing rapidly, and development of novel agents based on chemokine/ chemokine receptors antagonist functions are emerging as attractive alternative drugs. Some of these novel agents include generation of chemokine-derived peptides (CDP with potential agonist and antagonist effects on inflammation, cancer and against bacterial infections. CDP have been generated mainly from N- and C-terminus chemokine sequences with subsequent modifications such as truncations or elongations. In this review, we present a glimpse of the different pharmacological actions reported for CDP and our current understanding regarding the potential use of CDP alone or as part of the novel therapies proposed in the treatment of microbial infections and cancer.

  9. 表皮抗菌肽的研究进展%Skin-derived antimicrobial peptides

    Institute of Scientific and Technical Information of China (English)

    屈园园; 普雄明

    2012-01-01

    抗菌肽是在多种生物体中表达的具有抗菌活性的肽类物质总称.皮肤频繁与环境中的微生物接触而不被感染,表皮抗菌肽起了重要作用.人类表皮抗菌肽主要包括防御素和cathelicidin家族的LL-37,由于其具有普通抗生素所不具有的一系列优点,使其生物学活性和与皮肤屏障的关系成为目前研究的热点,对其深入研究为抵御疾病、延缓衰老、相关皮肤病的发病机制及治疗等方面带来了新的希望.%Antimicrobial peptides refer to all of the peptides with antimicrobial activity expressed in various types of organisms.Skin-derived antimicrobial peptides play an important role in the protection of skin against infection by frequently contacting microbes in the environment.They mainly consist of defensins and cathelicidin LL-37.Since skin-derived antimicrobial peptides possess a series of advantages which are lacked by common antibiotics,their biological activity and correlation with skin barrier have become a hot spot in present studies.Further researches into skin-derived antimicrobial peptides will provide new hopes for thedefense against diseases,delay of aging,disclosure of pathogenesis of and development of treatment for somedermatoses.

  10. Buforins: histone H2A-derived antimicrobial peptides from toad stomach.

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    Cho, Ju Hyun; Sung, Bong Hyun; Kim, Sun Chang

    2009-08-01

    Antimicrobial peptides (AMPs) constitute an important component of the innate immune system in a variety of organisms. Buforin I is a 39-amino acid AMP that was first isolated from the stomach tissue of the Asian toad Bufo bufo gargarizans. Buforin II is a 21-amino acid peptide that is derived from buforin I and displays an even more potent antimicrobial activity than its parent AMP. Both peptides share complete sequence identity with the N-terminal region of histone H2A that interacts directly with nucleic acids. Buforin I is generated from histone H2A by pepsin-directed proteolysis in the cytoplasm of gastric gland cells. After secretion into the gastric lumen, buforin I remains adhered to the mucous biofilm that lines the stomach, thus providing a protective antimicrobial coat. Buforins, which house a helix-hinge-helix domain, kill a microorganism by entering the cell without membrane permeabilization and thus binding to nucleic acids. The proline hinge is crucial for the cell penetrating activity of buforins. Buforins also are known to possess anti-endotoxin and anticancer activities, thus making these peptides attractive reagents for pharmaceutical applications. This review describes the role of buforins in innate host defense; future research paradigms; and use of these agents as human therapeutics.

  11. Antimicrobial Peptides in 2014

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    Guangshun Wang

    2015-03-01

    Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.

  12. Penetration of Milk-Derived Antimicrobial Peptides into Phospholipid Monolayers as Model Biomembranes

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    Wanda Barzyk

    2013-01-01

    Full Text Available Three antimicrobial peptides derived from bovine milk proteins were examined with regard to penetration into insoluble monolayers formed with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC or 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol sodium salt (DPPG. Effects on surface pressure (Π and electric surface potential (ΔV were measured, Π with a platinum Wilhelmy plate and ΔV with a vibrating plate. The penetration measurements were performed under stationary diffusion conditions and upon the compression of the monolayers. The two type measurements showed greatly different effects of the peptide-lipid interactions. Results of the stationary penetration show that the peptide interactions with DPPC monolayer are weak, repulsive, and nonspecific while the interactions with DPPG monolayer are significant, attractive, and specific. These results are in accord with the fact that antimicrobial peptides disrupt bacteria membranes (negative while no significant effect on the host membranes (neutral is observed. No such discrimination was revealed from the compression isotherms. The latter indicate that squeezing the penetrant out of the monolayer upon compression does not allow for establishing the penetration equilibrium, so the monolayer remains supersaturated with the penetrant and shows an under-equilibrium orientation within the entire compression range, practically.

  13. New Milk Protein-Derived Peptides with Potential Antimicrobial Activity: An Approach Based on Bioinformatic Studies

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    Dziuba, Bartłomiej; Dziuba, Marta

    2014-01-01

    New peptides with potential antimicrobial activity, encrypted in milk protein sequences, were searched for with the use of bioinformatic tools. The major milk proteins were hydrolyzed in silico by 28 enzymes. The obtained peptides were characterized by the following parameters: molecular weight, isoelectric point, composition and number of amino acid residues, net charge at pH 7.0, aliphatic index, instability index, Boman index, and GRAVY index, and compared with those calculated for known 416 antimicrobial peptides including 59 antimicrobial peptides (AMPs) from milk proteins listed in the BIOPEP database. A simple analysis of physico-chemical properties and the values of biological activity indicators were insufficient to select potentially antimicrobial peptides released in silico from milk proteins by proteolytic enzymes. The final selection was made based on the results of multidimensional statistical analysis such as support vector machines (SVM), random forest (RF), artificial neural networks (ANN) and discriminant analysis (DA) available in the Collection of Anti-Microbial Peptides (CAMP database). Eleven new peptides with potential antimicrobial activity were selected from all peptides released during in silico proteolysis of milk proteins. PMID:25141106

  14. New Milk Protein-Derived Peptides with Potential Antimicrobial Activity: An Approach Based on Bioinformatic Studies

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    Bartłomiej Dziuba

    2014-08-01

    Full Text Available New peptides with potential antimicrobial activity, encrypted in milk protein sequences, were searched for with the use of bioinformatic tools. The major milk proteins were hydrolyzed in silico by 28 enzymes. The obtained peptides were characterized by the following parameters: molecular weight, isoelectric point, composition and number of amino acid residues, net charge at pH 7.0, aliphatic index, instability index, Boman index, and GRAVY index, and compared with those calculated for known 416 antimicrobial peptides including 59 antimicrobial peptides (AMPs from milk proteins listed in the BIOPEP database. A simple analysis of physico-chemical properties and the values of biological activity indicators were insufficient to select potentially antimicrobial peptides released in silico from milk proteins by proteolytic enzymes. The final selection was made based on the results of multidimensional statistical analysis such as support vector machines (SVM, random forest (RF, artificial neural networks (ANN and discriminant analysis (DA available in the Collection of Anti-Microbial Peptides (CAMP database. Eleven new peptides with potential antimicrobial activity were selected from all peptides released during in silico proteolysis of milk proteins.

  15. The in Vitro Immune-Modulating Properties of a Sweat Gland-Derived Antimicrobial Peptide Dermcidin.

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    Wang, Echo; Qiang, Xiaoling; Li, Jianhua; Zhu, Shu; Wang, Ping

    2016-01-01

    The epidermal barriers of the skin serve as the first layer of defense by limiting the access of many pathogens to the blood circulation. In addition, human skin also contains sweat glands that can secrete a wide array of antimicrobial peptides to restrain the growth of various microbes. In the case of microbial infection, macrophages and monocytes constitute the first line of defense by producing a wide array of proinflammatory cytokines and chemokines. This process is triggered either by pathogen-associated molecular pattern molecules (such as bacterial endotoxin) or damage-associated molecular pattern molecules (such as HMGB1). In light of our findings that a sweat gland-derived antimicrobial peptide, dermcidin, affected both pathogen-associated molecular pattern and damage-associated molecular pattern-induced cytokines/chemokines by macrophages/monocytes, we propose that dermcidin may play an important role in the regulation of the innate immune responses to infection and injury. Future investigations are warranted to further test this understudied hypothesis in both preclinical and clinical settings.

  16. Antimicrobial Activity of a Halocidin-Derived Peptide Resistant to Attacks by Proteases ▿

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    Shin, Yong Pyo; Park, Ho Jin; Shin, Seo Hwa; Lee, Young Shin; Park, Seungmi; Jo, Sungho; Lee, Yong Ho; Lee, In Hee

    2010-01-01

    Cationic antimicrobial peptides (AMPs) have attracted a great deal of interest as a promising candidate for a novel class of antibiotics that might effectively treat recalcitrant infections caused by a variety of microbes that are resistant to currently available drugs. However, the AMPs are inherently limited in that they are inevitably susceptible to attacks by proteases generated by human and pathogenic microbes; this vulnerability severely hinders their pharmaceutical use in human therapeutic protocols. In this study, we report that a halocidin-derived AMP, designated HG1, was found to be resistant to proteolytic degradation. As a result of its unique structural features, HG1 proved capable of preserving its antimicrobial activity after incubation with trypsin, chymotrypsin, and human matrix metalloprotease 7 (MMP-7). Additionally, HG1 was observed to exhibit profound antimicrobial activity in the presence of fluid from human skin wounds or proteins extracted from the culture supernatants of Staphylococcus aureus and Pseudomonas aeruginosa. Greater understanding of the structural motifs of HG1 required for its protease resistance might provide feasible ways to solve the problems intrinsic to the development of an AMP-based antibiotic. PMID:20385874

  17. Factors affecting antimicrobial activity of MUC7 12-mer, a human salivary mucin-derived peptide

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    Bobek Libuse A

    2007-11-01

    Full Text Available Abstract Background MUC7 12-mer (RKSYKCLHKRCR, a cationic antimicrobial peptide derived from the human low-molecular-weight salivary mucin MUC7, possesses potent antimicrobial activity in vitro. In order to evaluate the potential therapeutic application of the MUC7 12-mer, we examined the effects of mono- and divalent cations, EDTA, pH, and temperature on its antimicrobial activity. Methods Minimal Inhibitory Concentrations (MICs were determined using a liquid growth inhibition assay in 96-well microtiter plates. MUC7 12-mer was added at concentrations of 1.56–50 μM. MICs were determined at three endpoints: MIC-0, MIC-1, and MIC-2 (the lowest drug concentration showing 10%, 25% and 50% of growth, respectively. To examine the effect of salts or EDTA, a checkerboard microdilution technique was used. Fractional inhibitory concentration index (FICi was calculated on the basis of MIC-0. The viability of microbial cells treated with MUC7 12-mer in the presence of sodium or potassium was also determined by killing assay or flow cytometry. Results The MICs of MUC7 12-mer against organisms tested ranged from 6.25–50 μM. For C. albicans, antagonism (FICi 4.5 was observed for the combination of MUC7 12-mer and calcium; however, there was synergism (FICi 0.22 between MUC7 12-mer and EDTA, and the synergism was retained in the presence of calcium at its physiological concentration (1–2 mM. No antagonism but additivity or indifference (FICi 0.55–2.5 was observed for the combination of MUC7 12-mer and each K+, Na+, Mg2+, or Zn2+. MUC7 12-mer peptide (at 25 μM also exerted killing activity in the presence of NaCl, (up to 25 mM for C. albicans and up to 150 mM for E. coli, a physiological concentration of sodium in the oral cavity and serum, respectively and retained candidacidal activity in the presence of KCl (up to 40 mM. The peptide exhibited higher inhibitory activity against C. albicans at pH 7, 8, and 9 than at pH 5 and 6, and temperature up to

  18. Antimicrobial activity of peptides derived from olive flounder lipopolysaccharide binding protein/bactericidal permeability-increasing protein (LBP/BPI).

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    Nam, Bo-Hye; Moon, Ji-Young; Park, Eun-Hee; Kim, Young-Ok; Kim, Dong-Gyun; Kong, Hee Jeong; Kim, Woo-Jin; Jee, Young Ju; An, Cheul Min; Park, Nam Gyu; Seo, Jung-Kil

    2014-10-17

    We describe the antimicrobial function of peptides derived from the C-terminus of the olive flounder LBP BPI precursor protein. The investigated peptides, namely, ofLBP1N, ofLBP2A, ofLBP4N, ofLBP5A, and ofLBP6A, formed α-helical structures, showing significant antimicrobial activity against several Gram-negative bacteria, Gram-positive bacteria, and the yeast Candida albicans, but very limited hemolytic activities. The biological activities of these five analogs were evaluated against biomembranes or artificial membranes for the development of candidate therapeutic agents. Gel retardation studies revealed that peptides bound to DNA and inhibited migration on an agarose gel. In addition, we demonstrated that ofLBP6A inhibited polymerase chain reaction. These results suggested that the ofLBP-derived peptide bactericidal mechanism may be related to the interaction with intracellular components such as DNA or polymerase.

  19. Antimicrobial Activity of Peptides Derived from Olive Flounder Lipopolysaccharide Binding Protein/Bactericidal Permeability-Increasing Protein (LBP/BPI

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    Bo-Hye Nam

    2014-10-01

    Full Text Available We describe the antimicrobial function of peptides derived from the C-terminus of the olive flounder LBP BPI precursor protein. The investigated peptides, namely, ofLBP1N, ofLBP2A, ofLBP4N, ofLBP5A, and ofLBP6A, formed α-helical structures, showing significant antimicrobial activity against several Gram-negative bacteria, Gram-positive bacteria, and the yeast Candida albicans, but very limited hemolytic activities. The biological activities of these five analogs were evaluated against biomembranes or artificial membranes for the development of candidate therapeutic agents. Gel retardation studies revealed that peptides bound to DNA and inhibited migration on an agarose gel. In addition, we demonstrated that ofLBP6A inhibited polymerase chain reaction. These results suggested that the ofLBP-derived peptide bactericidal mechanism may be related to the interaction with intracellular components such as DNA or polymerase.

  20. Prokaryotic expression and antimicrobial mechanism of XPF-St7-derived α-helical peptides.

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    Yi, Tonghui; Huang, Yibing; Chen, Yuxin

    2015-01-01

    XPF-St7 (GLLSNVAGLLKQFAKGGVNAVLNPK) is an antimicrobial peptide isolated from Silurana tropicalis. We developed an α-helical segment of XPF-St7 termed as XPF2. Using the XPF2 as a framework, we increased the positive net charge of XPF2 by amino acid substitutions, and thus obtained two novel antimicrobial peptides XPF4 and XPF6. These were each fused with an ubiquitin tag and successfully expressed in Escherichia coli. This ubiquitin fusion system may present a viable alternative for industrial production of antimicrobial peptides. XPF4 and XPF6 showed much better overall antimicrobial activity against both Gram-negative and Gram-positive bacteria than XPF2. The therapeutic index of XPF4 and XPF6 was 5.6-fold and 6.7-fold of XPF2, respectively. Bacterial cell membrane permeabilization and genomic DNA interaction assays were utilized to explore the mechanism of action of XPF serial peptides. The results revealed that the target of these antimicrobial peptides was the bacterial cytoplasmic membrane. PMID:25421112

  1. Prokaryotic expression and antimicrobial mechanism of XPF-St7-derived α-helical peptides.

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    Yi, Tonghui; Huang, Yibing; Chen, Yuxin

    2015-01-01

    XPF-St7 (GLLSNVAGLLKQFAKGGVNAVLNPK) is an antimicrobial peptide isolated from Silurana tropicalis. We developed an α-helical segment of XPF-St7 termed as XPF2. Using the XPF2 as a framework, we increased the positive net charge of XPF2 by amino acid substitutions, and thus obtained two novel antimicrobial peptides XPF4 and XPF6. These were each fused with an ubiquitin tag and successfully expressed in Escherichia coli. This ubiquitin fusion system may present a viable alternative for industrial production of antimicrobial peptides. XPF4 and XPF6 showed much better overall antimicrobial activity against both Gram-negative and Gram-positive bacteria than XPF2. The therapeutic index of XPF4 and XPF6 was 5.6-fold and 6.7-fold of XPF2, respectively. Bacterial cell membrane permeabilization and genomic DNA interaction assays were utilized to explore the mechanism of action of XPF serial peptides. The results revealed that the target of these antimicrobial peptides was the bacterial cytoplasmic membrane.

  2. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    Introduction: A frightening increase in the number of isolated multidrug resistant bacterial strains linked to the decline in novel antimicrobial drugs entering the market is a great cause for concern. Cationic antimicrobial peptides (AMPs) have lately been introduced as a potential new class of ...

  3. Antimicrobial Activity of Novel Synthetic Peptides Derived from Indolicidin and Ranalexin against Streptococcus pneumoniae.

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    Hassan Mahmood Jindal

    Full Text Available Antimicrobial peptides (AMPs represent promising alternatives to conventional antibiotics in order to defeat multidrug-resistant bacteria such as Streptococcus pneumoniae. In this study, thirteen antimicrobial peptides were designed based on two natural peptides indolicidin and ranalexin. Our results revealed that four hybrid peptides RN7-IN10, RN7-IN9, RN7-IN8, and RN7-IN6 possess potent antibacterial activity against 30 pneumococcal clinical isolates (MIC 7.81-15.62µg/ml. These four hybrid peptides also showed broad spectrum antibacterial activity (7.81µg/ml against S. aureus, methicillin resistant S. aureus (MRSA, and E. coli. Furthermore, the time killing assay results showed that the hybrid peptides were able to eliminate S. pneumoniae within less than one hour which is faster than the standard drugs erythromycin and ceftriaxone. The cytotoxic effects of peptides were tested against human erythrocytes, WRL-68 normal liver cell line, and NL-20 normal lung cell line. The results revealed that none of the thirteen peptides have cytotoxic or hemolytic effects at their MIC values. The in silico molecular docking study was carried out to investigate the binding properties of peptides with three pneumococcal virulent targets by Autodock Vina. RN7IN6 showed a strong affinity to target proteins; autolysin, pneumolysin, and pneumococcal surface protein A (PspA based on rigid docking studies. Our results suggest that the hybrid peptides could be suitable candidates for antibacterial drug development.

  4. Identification of peptides derived from the human antimicrobial peptide LL-37 active against biofilms formed by Pseudomonas aeruginosa using a library of truncated fragments

    NARCIS (Netherlands)

    C. Nagant; B. Pitts; K. Nazmi; M. Vandenbranden; J.G. Bolscher; P.S. Stewart; J-P. Dehaye

    2012-01-01

    Persistent Pseudomonas aeruginosa infections are a major cause of morbidity and mortality in cystic fibrosis (CF) patients and are linked to the formation of a biofilm. The development of new biofilm inhibition strategies is thus a major challenge. LL-37 is the only human antimicrobial peptide deriv

  5. Investigation into the mechanism of action of the antimicrobial peptides Os and Os-C derived from a tick defensin.

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    Taute, Helena; Bester, Megan J; Neitz, Albert W H; Gaspar, Anabella R M

    2015-09-01

    Os and Os-C are two novel antimicrobial peptides, derived from a tick defensin, which have been shown to have a larger range of antimicrobial activity than the parent peptide, OsDef2. The aim of this study was to determine whether the peptides Os and Os-C are mainly membrane acting, or if these peptides have possible additional intracellular targets in Escherichia coli and Bacillus subtilis. Transmission electron microscopy revealed that both peptides adversely affected intracellular structure of both bacteria causing different degrees of granulation of the intracellular contents. At the minimum bactericidal concentrations, permeabilization as determined with the SYTOX green assay seemed not to be the principle mode of killing when compared to melittin. However, fluorescent triple staining indicated that the peptides caused permeabilization of stationary phase bacteria and TEM indicated membrane effects. Studies using fluorescently labeled peptides revealed that the membrane penetrating activity of Os and Os-C was similar to buforin II. Os-C was found to associate with the septa of B. subtilis. Plasmid binding studies showed that Os and Os-C binds E. coli plasmid DNA at a similar charge ratio as melittin. These studies suggest membrane activity for Os and Os-C with possible intracellular targets such as DNA. The differences in permeabilization at lower concentrations and binding to DNA between Os and Os-C, suggest that the two peptides have dissimilar modes of action. PMID:26215047

  6. Anti-infective efficacy of the lactoferrin-derived antimicrobial peptide HLR1r.

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    Björn, Camilla; Mahlapuu, Margit; Mattsby-Baltzer, Inger; Håkansson, Joakim

    2016-07-01

    Antimicrobial peptides (AMPs) have emerged as a new class of drug candidates for the treatment of infectious diseases. Here we describe a novel AMP, HLR1r, which is structurally derived from the human milk protein lactoferrin and demonstrates a broad spectrum microbicidal action in vitro. The minimum concentration of HLR1r needed for killing ≥99% of microorganisms in vitro, was in the range of 3-50μg/ml for common Gram-negative and Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), and for the yeast Candida albicans, when assessed in diluted brain-heart infusion medium. We found that HLR1r also possesses anti-inflammatory properties as evidenced by inhibition of tumor necrosis factor alpha (TNF-α) secretion from human monocyte-derived macrophages and by repression of interleukin-6 (IL-6) and plasminogen activator inhibitor-1 (PAI-1) secretion from human mesothelial cells, without any cytotoxic effect observed at the concentration range tested (up to 400μg/ml). HLR1r demonstrated pronounced anti-infectious effect in in vivo experimental models of cutaneous candidiasis in mice and of excision wounds infected with MRSA in rats as well as in an ex vivo model of pig skin infected with S. aureus. In conclusion, HLR1r may constitute a new therapeutic alternative for local treatment of skin infections. PMID:27155369

  7. Optimization of expression conditions for a novel NZ2114-derived antimicrobial peptide-MP1102 under the control of the GAP promoter in Pichia pastoris X-33

    OpenAIRE

    Mao, Ruoyu; Teng, Da; Wang, Xiumin; Zhang, Yong; Jiao, Jian; Cao, Xintao; wang, Jianhua

    2015-01-01

    Background The infections caused by antibiotic multidrug-resistant bacteria seriously threaten human health. To prevent and cure the infections caused by multidrug-resistant bacteria, new antimicrobial agents are required. Antimicrobial peptides are ideal therapy candidates for antibiotic-resistant pathogens. However, due to high production costs, novel methods of large-scale production are urgently needed. Results The novel plectasin-derived antimicrobial peptide-MP1102 gene was constitutive...

  8. Cationic Antimicrobial Peptides Derived from Crocodylus siamensis Leukocyte Extract, Revealing Anticancer Activity and Apoptotic Induction on Human Cervical Cancer Cells.

    Science.gov (United States)

    Theansungnoen, Tinnakorn; Maijaroen, Surachai; Jangpromma, Nisachon; Yaraksa, Nualyai; Daduang, Sakda; Temsiripong, Theeranan; Daduang, Jureerut; Klaynongsruang, Sompong

    2016-06-01

    Known antimicrobial peptides KT2 and RT2 as well as the novel RP9 derived from the leukocyte extract of the freshwater crocodile (Crocodylus siamensis) were used to evaluate the ability in killing human cervical cancer cells. RP9 in the extract was purified by a combination of anion exchange column and reversed-phase HPLC, and its sequence was analyzed by mass spectrometry. The novel peptide could inhibit Gram-negative Vibrio cholerae (clinical isolation) and Gram-positive Bacillus pumilus TISTR 905, and its MIC values were 61.2 µM. From scanning electron microscopy, the peptide was seen to affect bacterial surfaces directly. KT2 and RT2, which are designed antimicrobial peptides using the C. siamensis Leucrocin I template, as well as RP9 were chemically synthesized for investigation of anticancer activity. By Sulforhodamine B colorimetric assay, these antimicrobial peptides could inhibit both HeLa and CaSki cancer cell lines. The IC50 values of KT2 and RT2 for HeLa and CaSki cells showed 28.7-53.4 and 17.3-30.8 µM, while those of RP9 were 126.2 and 168.3 µM, respectively. Additionally, the best candidate peptides KT2 and RT2 were used to determine the apoptotic induction on cancer cells by human apoptosis array assay. As a result, KT2 and RT2 were observed to induce apoptotic cell death in HeLa cells. Therefore, these results indicate that KT2 and RT2 with antimicrobial activity have a highly potent ability to kill human cervical cancer cells. PMID:27129462

  9. Antimicrobial Peptides (AMPs

    Directory of Open Access Journals (Sweden)

    Mehrzad Sadredinamin

    2016-04-01

    Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

  10. 皮肤抗菌肽的研究进展%Advances in skin-derived antimicrobial peptides

    Institute of Scientific and Technical Information of China (English)

    郑勇军; 夏照帆

    2013-01-01

    The antimicrobial peptides (AMP) are essential components of innate immunity.Human skin-derived antimicrobial peptides mainly include β-defensins and cathelicidins family and they are widely expressed in skin keratinocytes and inflammatory cells.Skin-derived antimicrobial peptides play important roles in skin,such as protecting skin from infection,regulating the immune response of skin,enhancing wound healing and angiogenesis.Their expressions are influenced by many factors in vivo and in vitro and closely related to various inflammatory diseases of skin.They may also play an important role in wound healing of diabetes.%抗菌肽是机体固有免疫的重要组成部分,人类皮肤抗菌肽主要包括cathelicidins家族和β-防御素家族,广泛表达于皮肤角质形成细胞及各种炎症细胞.皮肤抗菌肽除了直接杀菌作用外,还能调节免疫反应,促进伤口愈合和血管新生,其表达受到体内,体外多种因素的影响,与各种皮肤炎症性疾病发病密切相关,也可能在糖尿病创面愈合中发挥着重要作用.

  11. Micelle bound structure and DNA interaction of brevinin-2-related peptide, an antimicrobial peptide derived from frog skin.

    Science.gov (United States)

    Bandyopadhyay, Susmita; Ng, Boon Yee; Chong, Charmaine; Lim, Ming Zhen; Gill, Sonia Kiran; Lee, Ke Hui; Sivaraman, J; Chatterjee, Chiradip

    2014-10-01

    Brevinin-2-related peptide (BR-II), a novel antimicrobial peptide isolated from the skin of frog, Rana septentrionalis, shows a broad spectrum of antimicrobial activity with low haemolytic activity. It has also been shown to have antiviral activity, specifically to protect cells from infection by HIV-1. To understand the active conformation of the BR-II peptide in membranes, we have investigated the interaction of BR-II with the prokaryotic and eukaryotic membrane-mimetic micelles such as sodium dodecylsulfate (SDS) and dodecylphosphocholine (DPC), respectively. The interactions were studied using fluorescence and circular dichroism (CD) spectroscopy. Fluorescence experiments revealed that the N-terminus tryptophan residue of BR-II interacts with the hydrophobic core of the membrane mimicking micelles. The CD results suggest that interactions with membrane-mimetic micelles induce an α-helix conformation in BR-II. We have also determined the solution structures of BR-II in DPC and SDS micelles using NMR spectroscopy. The structural comparison of BR-II in the presence of SDS and DPC micelles showed significant conformational changes in the residues connecting the N-terminus and C-terminus helices. The ability of BR-II to bind DNA was elucidated by agarose gel retardation and fluorescence experiments. The structural differences of BR-II in zwitterionic versus anionic membrane mimics and the DNA binding ability of BR-II collectively contribute to the general understanding of the pharmacological specificity of this peptide towards prokaryotic and eukaryotic membranes and provide insights into its overall antimicrobial mechanism.

  12. Antimicrobial peptides in crustaceans

    Directory of Open Access Journals (Sweden)

    RD Rosa

    2010-11-01

    Full Text Available Crustaceans are a large and diverse invertebrate animal group that mounts a complex and efficient innate immune response against a variety of microorganisms. The crustacean immune system is primarily related to cellular responses and the production and release of important immune effectors into the hemolymph. Antimicrobial proteins and/or peptides (AMPs are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, 15 distinct AMP families are currently recognized, although the great majority (14 families comes from members of the order Decapoda. Crustacean AMPs are generally cationic, gene-encoded molecules that are mainly produced by circulating immune-competent cells (hemocytes or are derived from unrelated proteins primarily involved in other biological functions. In this review, we tentatively classified the crustacean AMPs into four main groups based on their amino acid composition, structural features and multi-functionality. We also attempted to summarize the current knowledge on their implication both in an efficient response to microbial infections and in crustacean survival.

  13. Molecular Characterization and Phylogenetic Analysis of a Histone-Derived Antimicrobial Peptide Teleostin from the Marine Teleost Fishes, Tachysurus jella and Cynoglossus semifasciatus.

    Science.gov (United States)

    Chaithanya, E R; Philip, Rosamma; Sathyan, Naveen; Anil Kumar, P R

    2013-01-01

    Antimicrobial peptides (AMPs) are host defense peptides that are well conserved throughout the course of evolution. Histones are classical DNA-binding proteins, rich in cationic amino acids, and recently appreciated as precursors for various histone-derived AMPs. The present study deals with identification of the potential antimicrobial peptide sequence of teleostin from the histone H2A of marine teleost fishes, Cynoglossus semifasciatus and Tachysurus jella. A 245 bp amplicon coding for 81 amino acids was obtained from the cDNA transcripts of these fishes. The first 52 amino acids from the N terminal of the peptide were identical to previously characterized histone-derived antimicrobial peptides. Molecular and physicochemical characterizations of the sequence were found to be in agreement with previously reported histone H2A-derived AMPs, suggesting the possible role of histone H2A in innate defense mechanism in fishes. PMID:27335674

  14. Model membrane interaction and DNA-binding of antimicrobial peptide Lasioglossin II derived from bee venom.

    Science.gov (United States)

    Bandyopadhyay, Susmita; Lee, Meryl; Sivaraman, J; Chatterjee, Chiradip

    2013-01-01

    Lasioglossins, a new family of antimicrobial peptide, have been shown to have strong antimicrobial activity with low haemo-lytic and mast cell degranulation activity, and exhibit cytotoxic activity against various cancer cells in vitro. In order to understand the active conformation of these pentadecapeptides in membranes, we have studied the interaction of Lasioglossin II (LL-II), one of the members of Lasioglossins family with membrane mimetic micelle Dodecylphosphocholine (DPC) by fluorescence, Circular Dichroism (CD) and two dimensional (2D) (1)H NMR spectroscopy. Fluorescence experiments provide evidence of interaction of the N-terminal tryptophan residue of LL-II with the hydrophobic core of DPC micelle. CD results show an extended chain conformation of LL-II in water which is converted to a partial helical conformation in the presence of DPC micelle. Moreover we have determined the first three-dimensional NMR structure of LL-II bound to DPC micelle with rmsd of 0.36Å. The solution structure of LL-II shows hydrophobic and hydrophilic core formation in peptide pointing towards different direction in the presence of DPC. This amphipathic structure may allow this peptide to penetrate deeply into the interfacial region of negatively charged membranes and leading to local membrane destabilization. Further we have elucidated the DNA binding ability of LL-II by agarose gel retardation and fluorescence quenching experiments.

  15. Antimicrobial peptides in Echinoderms

    Directory of Open Access Journals (Sweden)

    C Li

    2010-05-01

    Full Text Available Antimicrobial peptides (AMPs are important immune effector molecules for invertebrates, including echinoderms, which lack a vertebrate-type adaptive immune system. Here we summarize the knowledge of such peptides in echinoderms. Strongylocins are a novel family of cysteine-rich AMPs, recently identified in the sea urchins, Strongylocentrotus droebachiensis and S. purpuratus. Although these molecules present diverse amino acid sequences, they share an identical cysteine arrangement pattern, dissimilar to other known AMPs. A family of heterodimeric AMPs, named centrocins, are also present in S. droebachiensis. Lysozymes and fragments of larger proteins, such as beta-thymocins, actin, histone 2A and filamin A have also been shown to display antimicrobial activities in echinoderms. Future studies on AMPs should be aimed in revealing how echinoderms use these AMPs in the immune response against microbial pathogens.

  16. Design of antimicrobial peptides conjugated biodegradable citric acid derived hydrogels for wound healing.

    Science.gov (United States)

    Xie, Zhiwei; Aphale, Nikhil V; Kadapure, Tejaswi D; Wadajkar, Aniket S; Orr, Sara; Gyawali, Dipendra; Qian, Guoying; Nguyen, Kytai T; Yang, Jian

    2015-12-01

    Wound healing is usually facilitated by the use of a wound dressing that can be easily applied to cover the wound bed, maintain moisture, and avoid bacterial infection. In order to meet all of these requirements, we developed an in situ forming biodegradable hydrogel (iFBH) system composed of a newly developed combination of biodegradable poly(ethylene glycol) maleate citrate (PEGMC) and poly(ethylene glycol) diacrylate (PEGDA). The in situ forming hydrogel systems are able to conform to the wound shape in order to cover the wound completely and prevent bacterial invasion. A 2(k) factorial analysis was performed to examine the effects of polymer composition on specific properties, including the curing time, Young's modulus, swelling ratio, and degradation rate. An optimized iFBH formulation was achieved from the systematic factorial analysis. Further, in vitro biocompatibility studies using adult human dermal fibroblasts (HDFs) confirmed that the hydrogels and degradation products are not cytotoxic. The iFBH wound dressing was conjugated and functionalized with antimicrobial peptides as well. Evaluation against bacteria both in vitro and in vivo in rats demonstrated that the peptide-incorporated iFBH wound dressing offered excellent bacteria inhibition and promoted wound healing. These studies indicated that our in situ forming antimicrobial biodegradable hydrogel system is a promising candidate for wound treatment.

  17. Antimicrobial Peptides from Plants

    Science.gov (United States)

    Tam, James P.; Wang, Shujing; Wong, Ka H.; Tan, Wei Liang

    2015-01-01

    Plant antimicrobial peptides (AMPs) have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs) of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic), lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms. PMID:26580629

  18. Antimicrobial Peptides from Plants

    Directory of Open Access Journals (Sweden)

    James P. Tam

    2015-11-01

    Full Text Available Plant antimicrobial peptides (AMPs have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic, lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms.

  19. Human Antimicrobial Peptides and Proteins

    OpenAIRE

    Guangshun Wang

    2014-01-01

    As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs) play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified ...

  20. Spectral and biological evaluation of a synthetic antimicrobial peptide derived from 1-aminocyclohexane carboxylic acid.

    Science.gov (United States)

    Abercrombie, J J; Leung, Kai P; Chai, Hanbo; Hicks, Rickey P

    2015-03-15

    Ac-GF(A6c)G(A6c)K(A6c)G(A6c)F(A6c)G(A6c)GK(A6c)KKKK-amide (A6c=1-aminocyclohexane carboxylic acid) is a synthetic antimicrobial peptide (AMP) that exhibits in vitro inhibitory activity against drug resistant strains of Staphylococcus aureus, Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter aerogenes, and Enterococcus faecium at concentrations ranging from 10.9 to 43μM. Spectroscopic investigations were conducted to determine how this AMP interacts with simple membrane model systems in order to provide insight into possible mechanisms of action. CD and 2D-(1)H NMR experiments indicated this AMP on binding to SDS and DPC micelles adopts conformations with varying percentages of helical and random coil conformers. CD investigations in the presence of three phospholipid SUVs consisting of POPC, 4:1 POPC/POPG, and 60% POPE/21%POPG/19%POPC revealed: (1) The interactions occurring with POPC SUVs have minimal effect on the conformational diversity of the AMP yielding conformations similar to those observed in buffer. (2) The interactions with 4:1 POPC/POPG, and 60% POPE/21%POPG/19%POPC SUVs exhibited a greater influence on the percentage of different conformers contributing to the CD spectra. (3) The presence of a high of percentage of helical conformers was not observed in the presence of SUVs as was the case with micelles. This data indicates that the diversity of surface bound conformations adopted by this AMP are very different from the diversity of conformations adopted by this AMP on insertion into the lipid bilayer. CD spectra of this AMP in the presence of SUVs consisting of LPS isolated from P. aeruginosa, K. pneumoniae and Escherichia coli exhibited characteristics associated with various helical conformations.

  1. Antimicrobial cyclic peptides for plant disease control.

    Science.gov (United States)

    Lee, Dong Wan; Kim, Beom Seok

    2015-03-01

    Antimicrobial cyclic peptides derived from microbes bind stably with target sites, have a tolerance to hydrolysis by proteases, and a favorable degradability under field conditions, which make them an attractive proposition for use as agricultural fungicides. Antimicrobial cyclic peptides are classified according to the types of bonds within the ring structure; homodetic, heterodetic, and complex cyclic peptides, which in turn reflect diverse physicochemical features. Most antimicrobial cyclic peptides affect the integrity of the cell envelope. This is achieved through direct interaction with the cell membrane or disturbance of the cell wall and membrane component biosynthesis such as chitin, glucan, and sphingolipid. These are specific and selective targets providing reliable activity and safety for non-target organisms. Synthetic cyclic peptides produced through combinatorial chemistry offer an alternative approach to develop antimicrobials for agricultural uses. Those synthesized so far have been studied for antibacterial activity, however, the recent advancements in powerful technologies now promise to provide novel antimicrobial cyclic peptides that are yet to be discovered from natural resources.

  2. Antimicrobial Cyclic Peptides for Plant Disease Control

    Directory of Open Access Journals (Sweden)

    Dong Wan Lee

    2015-03-01

    Full Text Available Antimicrobial cyclic peptides derived from microbes bind stably with target sites, have a tolerance to hydrolysis by proteases, and a favorable degradability under field conditions, which make them an attractive proposition for use as agricultural fungicides. Antimicrobial cyclic peptides are classified according to the types of bonds within the ring structure; homodetic, heterodetic, and complex cyclic peptides, which in turn reflect diverse physicochemical features. Most antimicrobial cyclic peptides affect the integrity of the cell envelope. This is achieved through direct interaction with the cell membrane or disturbance of the cell wall and membrane component biosynthesis such as chitin, glucan, and sphingolipid. These are specific and selective targets providing reliable activity and safety for non-target organisms. Synthetic cyclic peptides produced through combinatorial chemistry offer an alternative approach to develop antimicrobials for agricultural uses. Those synthesized so far have been studied for antibacterial activity, however, the recent advancements in powerful technologies now promise to provide novel antimicrobial cyclic peptides that are yet to be discovered from natural resources.

  3. Anti-Microbial, Anti-Biofilm Activities and Cell Selectivity of the NRC-16 Peptide Derived from Witch Flounder, Glyptocephalus cynoglossus

    Directory of Open Access Journals (Sweden)

    Chang Ho Seo

    2013-05-01

    Full Text Available Previous studies had identified novel antimicrobial peptides derived from witch flounder. In this work, we extended the search for the activity of peptide that showed antibacterial activity on clinically isolated bacterial cells and bacterial biofilm. Pseudomonas aeruginosa was obtained from otitis media and cholelithiasis patients, while Staphylococcus aureus was isolated from otitis media patients. We found that synthetic peptide NRC-16 displays antimicrobial activity and is not sensitive to salt during its bactericidal activity. Interestingly, this peptide also led to significant inhibition of biofilm formation at a concentration of 4–16 μM. NRC-16 peptide is able to block biofilm formation at concentrations just above its minimum inhibitory concentration while conventional antibiotics did not inhibit the biofilm formation except ciprofloxacin and piperacillin. It did not cause significant lysis of human RBC, and is not cytotoxic to HaCaT cells and RAW264.7 cells, thereby indicating its selective antimicrobial activity. In addition, the peptide’s binding and permeation activities were assessed by tryptophan fluorescence, calcein leakage and circular dichroism using model mammalian membranes composed of phosphatidylcholine (PC, PC/cholesterol (CH and PC/sphingomyelin (SM. These experiments confirmed that NRC-16 does not interact with any of the liposomes but the control peptide melittin did. Taken together, we found that NRC-16 has potent antimicrobial and antibiofilm activities with less cytotoxicity, and thus can be considered for treatment of microbial infection in the future.

  4. Antimicrobial peptides in annelids

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    A Tasiemski

    2008-06-01

    Full Text Available Gene encoded antimicrobial peptides (AMPs are widely distributed among living organisms including plants, invertebrates and vertebrates. They constitute important effectors of the innate immune response by exerting multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cytokine release, cell proliferation, angiogenesis, wound healing, chemotaxis and immune induction. In invertebrates, most of the data describe the characterization and/or the function of AMPs in the numerically and economically most representative group which are arthropods. Annelids are among the first coelomates and are therefore of special phylogenetic interest. Compared to other invertebrate groups, data on annelid’s immunity reveal heavier emphasis on the cellular than on the humoral response suggesting that immune defense of annelids seems to be principally developed as cellular immunity.This paper gives an overview of the variety of AMPs identified in the three classes of annelids, i.e. polychaetes, oligochaetes and achaetes. Their functions, when they have been studied, in the humoral or cellular response of annelids are also mentioned.

  5. Novel Formulations for Antimicrobial Peptides

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    Ana Maria Carmona-Ribeiro

    2014-10-01

    Full Text Available Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy.

  6. Antimicrobial activity, improved cell selectivity and mode of action of short PMAP-36-derived peptides against bacteria and Candida.

    Science.gov (United States)

    Lyu, Yinfeng; Yang, Yang; Lyu, Xiting; Dong, Na; Shan, Anshan

    2016-01-01

    Antimicrobial peptides (AMPs) have recently attracted a great deal of attention as promising antibiotic candidates, but some obstacles such as toxicity and high synthesis cost must be addressed before developing them further. For developing short peptides with improved cell selectivity, we designed a series of modified PMAP-36 analogues. Antimicrobial assays showed that decreasing chain length in a certain range retained the high antimicrobial activity of the parental peptide and reduced hemolysis. The 18-mer peptide RI18 exhibited excellent antimicrobial activity against both bacteria and fungi, and its hemolytic activity was observably lower than PMAP-36 and melittin. The selectivity indexes of RI18 against bacteria and fungi were improved approximately 19-fold and 108-fold, respectively, compared to PMAP-36. In addition, serum did not affect the antibacterial activity of RI18 against E. coli but inhibited the antifungal efficiency against C. albicans. Flow cytometry and electron microscopy observation revealed that RI18 killed microbial cells primarily by damaging membrane integrity, leading to whole cell lysis. Taken together, these results suggest that RI18 has potential for further therapeutic research against frequently-encountered bacteria and fungi. Meanwhile, modification of AMPs is a promising strategy for developing novel antimicrobials to overcome drug-resistance. PMID:27251456

  7. An exceptional salt tolerant antimicrobial peptide derived from a novel gene family of hemocytes of the marine invertebrate Ciona intestinalis

    OpenAIRE

    Fedders, Henning; Michalek, Matthias; Grötzinger, Joachim; Leippe, Matthias

    2008-01-01

    Abstract A novel gene family coding for putative antimicrobial peptides was identified in the EST data base of the sea squirt Ciona intestinalis, and one of these genes was molecularly cloned from the Northern European Ciona subspecies. In situ hybridisation and immunocytochemical analysis revealed that the natural peptide is synthesized and stored in a distinct hemocyte type, the univacuolar non-refractile granulocytes. By semiquantitative RT-PCR analysis it was shown that the exp...

  8. Absence of in vitro innate immunomodulation by insect-derived short proline-rich antimicrobial peptides points to direct antibacterial action in vivo.

    Science.gov (United States)

    Fritsche, Stefanie; Knappe, Daniel; Berthold, Nicole; von Buttlar, Heiner; Hoffmann, Ralf; Alber, Gottfried

    2012-10-01

    Some antimicrobial peptides (AMPs) have been described to exert immunomodulatory effects, which may contribute to their in vivo antibacterial activity. Very recently, we could show that novel oncocin and apidaecin derivatives are potently antibacterially active in vivo. Therefore, we studied oncocin and apidaecin derivatives for their effects on murine dendritic cells (DC) and macrophages and compared them with well-known immunomodulatory activities of murine cathelicidin-related antimicrobial peptide (CRAMP). To characterize the immunomodulatory activity of the peptides on key cells of the innate immune system, we stimulated murine DC and macrophages with the oncocin and apidaecin derivatives alone, or in combination with lipopolysaccharide (LPS). We analyzed the secretion of pro-inflammatory cytokines, the expression of surface activation markers, and the chemotactic activity of the AMPs. In contrast to LPS, none of the oncocin and apidaecin derivatives alone has an influence on cytokine or surface marker expression by DC and macrophages. Furthermore, the tested oncocin and apidaecin derivatives do not modulate the immune response after LPS stimulation, whereas CRAMP shows a reduction of the LPS-mediated immune response as expected. All peptides tested are not chemotactic for DC. Together, lack of in vitro immunomodulatory effects by oncocin and apidaecin derivatives on key cells of the innate murine immune system suggests that their potent in vivo antibacterial activity relies on a direct antibacterial effect. This will simplify further pharmaceutical investigation and development of insect peptides as therapeutic compounds against bacterial infections.

  9. Presence of chromogranin-derived antimicrobial peptides in plasma during coronary artery bypass surgery and evidence of an immune origin of these peptides.

    Science.gov (United States)

    Tasiemski, Aurélie; Hammad, Hamida; Vandenbulcke, Franck; Breton, Christophe; Bilfinger, Thomas J; Pestel, Joel; Salzet, Michel

    2002-07-15

    Chromogranin A (CGA) and chromogranin B (CGB) are acidic proteins stored in secretory organelles of endocrine cells and neurons. In addition to their roles as helper proteins in the packaging of peptides, they may serve as prohormones to generate biologically active peptides such as vasostatin-1 and secretolytin. These molecules derived from CGA and CGB, respectively, possess antimicrobial properties. The present study demonstrates that plasmatic levels of both vasostatin-1 and secretolytin increase during surgery in patients undergoing cardiopulmonary bypass (CPB). Vasostatin-1 and secretolytin, initially present in plasma at low levels, are released just after skin incision. Consequently, they can be added to enkelytin, an antibacterial peptide derived from proenkephalin A, for the panoply of components acting as a first protective barrier against hypothetical invasion of pathogens, which may occur during surgery. CGA and CGB, more commonly viewed as markers for endocrine and neuronal cells, were also found to have an immune origin. RNA messengers coding for CGB were amplified by reverse transcription-polymerase chain reaction in human monocytes, and immunocytochemical analysis by confocal microscopy revealed the presence of CGA or CGB or both in monocytes and neutrophils. A combination of techniques including confocal microscopic analysis, mass spectrometry measurement, and antibacterial tests allowed for the identification of the positive role of interleukin 6 (IL-6) in the secretolytin release from monocytes in vitro. Because IL-6 release is known to be strongly enhanced during CPB, we suggest a possible relationship between IL-6 and the increased level of secretolytin in patients undergoing CPB. PMID:12091348

  10. Cathelicidin-BF, a snake cathelicidin-derived antimicrobial peptide, could be an excellent therapeutic agent for acne vulgaris.

    Directory of Open Access Journals (Sweden)

    Yipeng Wang

    Full Text Available Cathelicidins are a family of antimicrobial peptides acting as multifunctional effector molecules in innate immunity. Cathelicidin-BF has been purified from the snake venoms of Bungarus fasciatus and it is the first identified cathelicidin antimicrobial peptide in reptiles. In this study, cathelicidin-BF was found exerting strong antibacterial activities against Propionibacterium acnes. Its minimal inhibitory concentration against two strains of P. acnes was 4.7 µg/ml. Cathelicidin-BF also effectively killed other microorganisms including Staphylococcus epidermidis, which was possible pathogen for acne vulgaris. Cathelicidin-BF significantly inhibited pro-inflammatory factors secretion in human monocytic cells and P. acnes-induced O2.- production of human HaCaT keratinocyte cells. Observed by scanning electron microscopy, the surfaces of the treated pathogens underwent obvious morphological changes compared with the untreated controls, suggesting that this antimicrobial peptide exerts its action by disrupting membranes of microorganisms. The efficacy of cathelicidin-BF gel topical administering was evaluated in experimental mice skin colonization model. In vivo anti-inflammatory effects of cathelicidin-BF were confirmed by relieving P. acnes-induced mice ear swelling and granulomatous inflammation. The anti-inflammatory effects combined with potent antimicrobial activities and O2.- production inhibition activities of cathelicidin-BF indicate its potential as a novel therapeutic option for acne vulgaris.

  11. Production of an antimicrobial peptide derived from slaughterhouse by-product and its potential application on meat as preservative.

    Science.gov (United States)

    Przybylski, Rémi; Firdaous, Loubna; Châtaigné, Gabrielle; Dhulster, Pascal; Nedjar, Naïma

    2016-11-15

    Bovine cruor, a slaughterhouse by-product, contains mainly hemoglobin, broadly described as a rich source of antimicrobial peptides. In the current context of food safety, bioactive peptides could be of interest as preservatives in the distribution of food products. The aim of this work was to study the α137-141 fragment of hemoglobin (Thr-Ser-Lys-Tyr-Arg), a small (653Da) and hydrophilic antimicrobial peptide. Its production was fast, with more 65% finally produced at 24h already produced after 30min of hydrolysis with pepsin. Moreover, increasing substrate concentration (from 1 to 8% (w/v)) resulted in a proportional augmentation of α137-141 production (to 807.95±41.03mgL(-1)). The α137-141 application on meat as preservative (0.5%, w/w) reduced the lipid oxidation about 60% to delay meat rancidity. The α137-141 peptide also inhibited the microbial growths under refrigeration during 14days. These antimicrobial effects were close to those of the butylated hydroxytoluene (BHT). PMID:27283637

  12. Collagen-like antimicrobial peptides.

    Science.gov (United States)

    Masuda, Ryo; Kudo, Masakazu; Dazai, Yui; Mima, Takehiko; Koide, Takaki

    2016-11-01

    Combinatorial library composed of rigid rod-like peptides with a triple-helical scaffold was constructed. The component peptides were designed to have various combinations of basic and neutral (or hydrophobic) amino acid residues based on collagen-like (Gly-Pro-Yaa)-repeating sequences, inspired from the basic and amphiphilic nature of naturally occurring antimicrobial peptides. Screening of the peptide pools resulted in identification of antimicrobial peptides. A structure-activity relationship study revealed that the position of Arg-cluster at N-terminus and cystine knots at C-terminus in the triple helix significantly contributed to the antimicrobial activity. The most potent peptide RO-A showed activity against Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. In addition, Escherichia coli exposed to RO-A resulted in abnormal elongation of the cells. RO-A was also shown to have remarkable stability in human serum and low cytotoxicity to mammalian cells. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 453-459, 2016. PMID:27271210

  13. Ultrashort cationic naphthalene-derived self-assembled peptides as antimicrobial nanomaterials.

    Science.gov (United States)

    Laverty, Garry; McCloskey, Alice P; Gilmore, Brendan F; Jones, David S; Zhou, Jie; Xu, Bing

    2014-09-01

    Self-assembling dipeptides conjugated to naphthalene show considerable promise as nanomaterial structures, biomaterials, and drug delivery devices. Biomaterial infections are responsible for high rates of patient mortality and morbidity. The presence of biofilm bacteria, which thrive on implant surfaces, are a huge burden on healthcare budgets, as they are highly resistant to current therapeutic strategies. Ultrashort cationic self-assembled peptides represent a highly innovative and cost-effective strategy to form antibacterial nanomaterials. Lysine conjugated variants display the greatest potency with 2% w/v NapFFKK hydrogels significantly reducing the viable Staphylococcus epidermidis biofilm by 94%. Reducing the size of the R-group methylene chain on cationic moieties resulted in reduction of antibiofilm activity. The primary amine of the protruding R-group tail may not be as readily available to interact with negatively charged bacterial membranes. Cryo-SEM, FTIR, CD spectroscopy, and oscillatory rheology provided evidence of supramolecular hydrogel formation at physiological pH (pH 7.4). Cytotoxicity assays against murine fibroblast (NCTC 929) cell lines confirmed the gels possessed reduced cytotoxicity relative to bacterial cells, with limited hemolysis upon exposure to equine erythrocytes. The results presented in this paper highlight the significant potential of ultrashort cationic naphthalene peptides as future biomaterials.

  14. An enhancer peptide for membrane-disrupting antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    Zhang Hong

    2010-02-01

    Full Text Available Abstract Background NP4P is a synthetic peptide derived from a natural, non-antimicrobial peptide fragment (pro-region of nematode cecropin P4 by substitution of all acidic amino acid residues with amides (i.e., Glu → Gln, and Asp → Asn. Results In the presence of NP4P, some membrane-disrupting antimicrobial peptides (ASABF-α, polymyxin B, and nisin killed microbes at lower concentration (e.g., 10 times lower minimum bactericidal concentration for ASABF-α against Staphylococcus aureus, whereas NP4P itself was not bactericidal and did not interfere with bacterial growth at ≤ 300 μg/mL. In contrast, the activities of antimicrobial agents with a distinct mode of action (indolicidin, ampicillin, kanamycin, and enrofloxacin were unaffected. Although the membrane-disrupting activity of NP4P was slight or undetectable, ASABF-α permeabilized S. aureus membranes with enhanced efficacy in the presence of NP4P. Conclusions NP4P selectively enhanced the bactericidal activities of membrane-disrupting antimicrobial peptides by increasing the efficacy of membrane disruption against the cytoplasmic membrane.

  15. Melittin, a honeybee venom‑derived antimicrobial peptide, may target methicillin‑resistant Staphylococcus aureus.

    Science.gov (United States)

    Choi, Ji Hae; Jang, A Yeung; Lin, Shunmei; Lim, Sangyong; Kim, Dongho; Park, Kyungho; Han, Sang-Mi; Yeo, Joo-Hong; Seo, Ho Seong

    2015-11-01

    Methicillin‑resistant Staphylococcus aureus (MRSA) is difficult to treat using available antibiotic agents. Honeybee venom has been widely used as an oriental treatment for several inflammatory diseases and bacterial infections. The venom contains predominantly biologically active compounds, however, the therapeutic effects of such materials when used to treat MRSA infections have not been investigated extensively. The present study evaluated bee venom and its principal active component, melittin, in terms of their antibacterial activities and in vivo protection against MRSA infections. In vitro, bee venom and melittin exhibited comparable levels of antibacterial activity, which was more marked against MRSA strains, compared with other Gram‑positive bacteria. When MRSA‑infected mice were treated with bee venom or melittin, only the latter animals were successfully rescued from MRSA‑ induced bacteraemia or exhibited recovery from MRSA‑infected skin wounds. Together, the data of the present study demonstrated for the first time, to the best of our knowledge, that melittin may be used as a promising antimicrobial agent to enhance the healing of MRSA‑induced wounds. PMID:26330195

  16. Antimicrobial activity of mosquito cecropin peptides against Francisella.

    Science.gov (United States)

    Kaushal, Akanksha; Gupta, Kajal; Shah, Ruhee; van Hoek, Monique L

    2016-10-01

    Francisella tularensis is the cause of the zoonotic disease tularemia. In Sweden and Scandinavia, epidemiological studies have implicated mosquitoes as a vector. Prior research has demonstrated the presence of Francisella DNA in infected mosquitoes but has not shown definitive transmission of tularemia from a mosquito to a mammalian host. We hypothesized that antimicrobial peptides, an important component of the innate immune system of higher organisms, may play a role in mosquito host-defense to Francisella. We established that Francisella sp. are susceptible to two cecropin antimicrobial peptides derived from the mosquito Aedes albopictus as well as Culex pipiens. We also demonstrated induced expression of Aedes albopictus antimicrobial peptide genes by Francisella infection C6/36 mosquito cell line. We demonstrate that mosquito antimicrobial peptides act against Francisella by disrupting the cellular membrane of the bacteria. Thus, it is possible that antimicrobial peptides may play a role in the inability of mosquitoes to establish an effective natural transmission of tularemia. PMID:27235883

  17. Epithelial antimicrobial peptides in host defense against infection

    Directory of Open Access Journals (Sweden)

    Bals Robert

    2000-10-01

    Full Text Available Abstract One component of host defense at mucosal surfaces seems to be epithelium-derived antimicrobial peptides. Antimicrobial peptides are classified on the basis of their structure and amino acid motifs. Peptides of the defensin, cathelicidin, and histatin classes are found in humans. In the airways, α-defensins and the cathelicidin LL-37/hCAP-18 originate from neutrophils. β-Defensins and LL-37/hCAP-18 are produced by the respiratory epithelium and the alveolar macrophage and secreted into the airway surface fluid. Beside their direct antimicrobial function, antimicrobial peptides have multiple roles as mediators of inflammation with effects on epithelial and inflammatory cells, influencing such diverse processes as proliferation, immune induction, wound healing, cytokine release, chemotaxis, protease-antiprotease balance, and redox homeostasis. Further, antimicrobial peptides qualify as prototypes of innovative drugs that might be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation.

  18. Evaluation of the Therapeutic Properties of Mastoparan- and Sifuvirtide- Derivative Antimicrobial Peptides Using Chemical Structure-Function Relationship - in vivo and in silico Approaches.

    Science.gov (United States)

    Avram, Speranta; Mernea, Maria; Borcan, Florin; Mihailescu, Dan

    2016-01-01

    Antimicrobial peptides, also called body defense peptides, are chemical structures widely distributed across the animal and vegetal kingdoms that have a fundamental role as part of the immune system. These peptides are used against a wide range of pathogens, such as Gram-negative and - positive bacteria, fungi and viruses, etc. Their action spectrum makes them important for the pharmaceutical industry, as they could represent templates for the design of new and more potent structures by using drug design and drug delivery systems. Here we present the antimicrobial activity against Bacillus subtilis (expressed as minimal inhibitory concentration values) for 33 mastoparan analogs and their new derivatives by quantitative structure-activity relationship method (2D, aligned and also non-aligned 3D-QSAR). We establish the contribution to antimicrobial activity of molecular descriptors like hydrophobicity, hydrogen bond donor and steric hindrance, correlated with contributions from the membrane environment (sodium, potassium, chloride ions). Also the studies of HIV-1 fusion inhibitor sifuvirtide and its analogs are presented in context of interaction with lipid structures during fusion and delivery of these drugs.

  19. In vivo Toxicity Assessment of Antimicrobial Peptides (AMPs LR14) Derived from Lactobacillus plantarum Strain LR/14 in Drosophila melanogaster.

    Science.gov (United States)

    Gupta, Ruchi; Sarkar, Surajit; Srivastava, Sheela

    2014-03-01

    Lactic acid bacteria are known to produce antimicrobial peptides (AMPs) such as bacteriocins which can be employed to control pathogens and food spoilage microorganisms. However, their possible role as toxic agents against a eukaryotic system still remains unexplored. The present study deals with the in vivo evaluation of acute toxic effect of AMPs LR14, a mixture of AMPs isolated from Lactobacillus plantarum LR/14 on Drosophila melanogaster. The fly was used as a model system to measure the extent of toxicity of these peptides. The results showed that concentrations below 10 mg/ml are not significantly effective. When exposed to 10 mg/ml of AMPs LR14, acute toxic effect and a significant delay in the developmental cycle of the fly could be observed. Also, the weight and size of the flies were significantly reduced upon ingestion of these peptides. Higher concentrations (beyond 15 mg/ml) exerted a strong larvicidal effect. Detailed analysis on larval tissues and adult germ cells of the insect revealed deformity in cellular architecture, DNA fragmentation, and premature apoptosis, confirming that the peptides have a dose-dependent toxic property. Our studies provide the first information on the role of AMPs LR14 as an insecticidal agent.

  20. Insect inducible antimicrobial peptides and their applications.

    Science.gov (United States)

    Ezzati-Tabrizi, Reyhaneh; Farrokhi, Naser; Talaei-Hassanloui, Reza; Alavi, Seyed Mehdi; Hosseininaveh, Vahid

    2013-12-01

    Antimicrobial peptides (AMPs) are found as important components of the innate immune system (host defense) of all invertebrates. These peptides can be constitutively expressed or induced in response to microbial infections. Indeed, they vary in their amino acid sequences, potency and antimicrobial activity spectra. The smaller AMPs act greatly by disrupting the structure or function of microbial cell membranes. Here, the insect innate immune system with emphasis on inducible antimicrobial peptide properties against microbial invaders has been discussed.

  1. Characterization of Histone H2A Derived Antimicrobial Peptides, Harriottins, from Sicklefin Chimaera Neoharriotta pinnata (Schnakenbeck, 1931) and Its Evolutionary Divergence with respect to CO1 and Histone H2A.

    Science.gov (United States)

    Sathyan, Naveen; Philip, Rosamma; Chaithanya, E R; Anil Kumar, P R; Sanjeevan, V N; Singh, I S Bright

    2013-01-01

    Antimicrobial peptides (AMPs) are humoral innate immune components of fishes that provide protection against pathogenic infections. Histone derived antimicrobial peptides are reported to actively participate in the immune defenses of fishes. Present study deals with identification of putative antimicrobial sequences from the histone H2A of sicklefin chimaera, Neoharriotta pinnata. A 52 amino acid residue termed Harriottin-1, a 40 amino acid Harriottin-2, and a 21 mer Harriottin-3 were identified to possess antimicrobial sequence motif. Physicochemical properties and molecular structure of Harriottins are in agreement with the characteristic features of antimicrobial peptides, indicating its potential role in innate immunity of sicklefin chimaera. The histone H2A sequence of sicklefin chimera was found to differ from previously reported histone H2A sequences. Phylogenetic analysis based on histone H2A and cytochrome oxidase subunit-1 (CO1) gene revealed N. pinnata to occupy an intermediate position with respect to invertebrates and vertebrates. PMID:27398241

  2. Antimicrobial Peptides: Versatile Biological Properties

    Directory of Open Access Journals (Sweden)

    Muthuirulan Pushpanathan

    2013-01-01

    Full Text Available Antimicrobial peptides are diverse group of biologically active molecules with multidimensional properties. In recent past, a wide variety of AMPs with diverse structures have been reported from different sources such as plants, animals, mammals, and microorganisms. The presence of unusual amino acids and structural motifs in AMPs confers unique structural properties to the peptide that attribute for their specific mode of action. The ability of these active AMPs to act as multifunctional effector molecules such as signalling molecule, immune modulators, mitogen, antitumor, and contraceptive agent makes it an interesting candidate to study every aspect of their structural and biological properties for prophylactic and therapeutic applications. In addition, easy cloning and recombinant expression of AMPs in heterologous plant host systems provided a pipeline for production of disease resistant transgenic plants. Besides these properties, AMPs were also used as drug delivery vectors to deliver cell impermeable drugs to cell interior. The present review focuses on the diversity and broad spectrum antimicrobial activity of AMPs along with its multidimensional properties that could be exploited for the application of these bioactive peptides as a potential and promising drug candidate in pharmaceutical industries.

  3. Antimicrobial peptides in the brain.

    Science.gov (United States)

    Su, Yanhua; Zhang, Kai; Schluesener, Hermann J

    2010-10-01

    Antimicrobial peptides (AMPs) are an evolutionarily conserved component of the innate immune system of many species. The brain is an immunologically privileged organ but can produce a robust immune response against pathogens and cell debris, promoting rapid and efficient clearance. AMPs may be critically involved in the innate immune system of the brain. Though the mechanisms of AMPs' action in the brain still need further elucidation, many studies have shown that AMPs are multifunctional molecules in the brain. In addition to antimicrobial action, they take part in congenital and adaptive immune reactions (immunoregulation), function as signaling molecules in tissue repair, inflammation and other important processes through different mechanisms, and they might, in addition, become diagnostic markers of brain disease.

  4. Antimicrobial activity of fibrinogen and fibrinogen-derived peptides--a novel link between coagulation and innate immunity.

    Science.gov (United States)

    Påhlman, L I; Mörgelin, M; Kasetty, G; Olin, A I; Schmidtchen, A; Herwald, H

    2013-05-01

    Fibrinogen is a key player in the blood coagulation system, and is upon activation with thrombin converted into fibrin that subsequently forms a fibrin clot. In the present study, we investigated the role of fibrinogen in the early innate immune response. Here we show that the viability of fibrinogen-binding bacteria is affected in human plasma activated with thrombin. Moreover, we found that the peptide fragment GHR28 released from the β-chain of fibrinogen has antimicrobial activity against bacteria that bind fibrinogen to their surface, whereas non-binding strains are unaffected. Notably, bacterial killing was detected in Group A Streptococcus bacteria entrapped in a fibrin clot, suggesting that fibrinogen and coagulation is involved in the early innate immune system to quickly wall off and neutralise invading pathogens.

  5. Human Antimicrobial Peptides and Proteins

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2014-05-01

    Full Text Available As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between −3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32 can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized

  6. Antimicrobial peptides in human sepsis

    Directory of Open Access Journals (Sweden)

    Lukas eMartin

    2015-08-01

    Full Text Available Nearly 100 years ago, antimicrobial peptides (AMPs were identified as an important part of innate immunity. They exist in species from bacteria to mammals and can be isolated in body fluids and on surfaces constitutively or induced by inflammation. Defensins have anti-bacterial effects against Gram-positive and Gram-negative bacteria as well as anti-viral and anti-yeast effects. Human neutrophil peptides (HNP 1-3 and human beta-defensins (HBDs 1-3 are some of the most important defensins in humans. Recent studies have demonstrated higher levels of HNP -1-3 and HBD-2 in sepsis. The bactericidal/permeability increasing protein (BPI attenuates local inflammatory response and decreases systemic toxicity of endotoxins. Moreover, BPI might reflect the severity of organ dysfunction in sepsis. Elevated plasma lactoferrin is detected in patients with organ failure. HNP-1-3, lactoferrin, BPI and heparin-binding protein (HBP are increased in sepsis. Human lactoferrin peptide 1-11 (hLF 1-11 possesses antimicrobial activity and modulates inflammation. The recombinant form of lactoferrin (talactoferrin alpha, TLF has been shown to decrease mortality in critically ill patients. A phase II/III study with TLF in sepsis did not confirm this result. The growing number of multiresistant bacteria is an ongoing problem in sepsis therapy. Furthermore, antibiotics are known to promote the liberation of pro-inflammatory cell components and thus augment the severity of sepsis. Compared to antibiotics, AMPs kill bacteria but also neutralize pathogenic factors such as lipopolysaccharide (LPS. The obstacle to applying naturally occurring AMPs is their high nephro- and neurotoxicity. Therefore, the challenge is to develop peptides to treat septic patients effectively without causing harm. This overview focuses on natural and synthetic AMPs in human and experimental sepsis and their potential to provide significant improvements in the treatment of critically ill with severe

  7. Antimicrobial peptides in Caenorhabditis elegans

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    A Bogaerts

    2010-01-01

    Full Text Available The nematode Caenorhabditis elegans is one of the most successful model species for experimental research because of its sequenced genome, the versatile genetic toolkit and the straightforward breeding among others. In natural conditions however, this tiny worm is constantly surrounded by micro-organisms, simultaneously a source of indispensable nutrition and inevitable pathogens. Lacking an adaptive immune system, the worm solely relies on its innate immune defence to cope with its challenging life style. Hence C. elegans is an excellent model to gain more insight in innate immunity, which is remarkably preserved between invertebrate and vertebrate animals. The innate defence consists of receptors to detect potential pathogens, a complex network of signalling pathways and last but not least, effector molecules to abolish harmful microbes. In this review, we focus on the antimicrobial peptides, a vital subgroup of effector molecules. We summarise the current knowledge of the different families of C. elegans antimicrobial peptides, comprising NLPs, caenacins, ABFs, caenopores, and a recently discovered group with antifungal activity among which thaumatin-like proteins.

  8. Antimicrobial peptides important in innate immunity.

    Science.gov (United States)

    Cederlund, Andreas; Gudmundsson, Gudmundur H; Agerberth, Birgitta

    2011-10-01

    Antimicrobial peptides are present in all walks of life, from plants to animals, and they are considered to be endogenous antibiotics. In general, antimicrobial peptides are determinants of the composition of the microbiota and they function to fend off microbes and prevent infections. Antimicrobial peptides eliminate micro-organisms through disruption of their cell membranes. Their importance in human immunity, and in health as well as disease, has only recently been appreciated. The present review provides an introduction to the field of antimicrobial peptides in general and discusses two of the major classes of mammalian antimicrobial peptides: the defensins and the cathelicidins. The review focuses on their structures, their main modes of action and their regulation.

  9. Membrane-bound structure and alignment of the antimicrobial {beta}-sheet peptide gramicidin S derived from angular and distance constraints by solid state 19F-NMR

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Jesus; Grage, Stephan L. [University of Jena, Department of Molecular Biology (Germany); Kondejewski, Leslie H. [University of Alberta, Protein Engineering Network of Centres of Excellence (Canada); Hodges, Robert S.; McElhaney, Ronald N. [University of Alberta, Department of Biochemistry (Canada); Ulrich, Anne S. [University of Jena, Department of Molecular Biology (Germany)

    2001-11-15

    The antimicrobial properties of the cyclic {beta}-sheet peptide gramicidin S are attributed to its destabilizing effect on lipid membranes. Here we present the membrane-bound structure and alignment of a derivative of this peptide, based on angular and distance constraints. Solid-state {sup 19}F-NMR was used to study a {sup 19}F-labelled gramicidin S analogue in dimyristoylphosphatidylcholine bilayers at a lipid:peptide ratio of 80:1 and above. Two equivalent leucine side chains were replaced by the non-natural amino acid 4F-phenylglycine, which serves as a highly sensitive reporter on the structure and dynamics of the peptide backbone. Using a modified CPMG multipulse sequence, the distance between the two {sup 19}F-labels was measured from their homonuclear dipolar coupling as 6 A, in good agreement with the known backbone structure of natural gramicidin S in solution. By analyzing the anisotropic chemical shift of the {sup 19}F-labels in macroscopically oriented membrane samples, we determined the alignment of the peptide in the bilayer and described its temperature-dependent mobility. In the gel phase, the {sup 19}F-labelled gramicidin S is aligned symmetrically with respect to the membrane normal, i.e., with its cyclic {beta}-sheet backbone lying flat in the plane of the bilayer, which is fully consistent with its amphiphilic character. Upon raising the temperature to the liquid crystalline state, a considerable narrowing of the {sup 19}F-NMR chemical shift dispersion is observed, which is attributed the onset of global rotation of the peptide and further wobbling motions. This study demonstrates the potential of the {sup 19}F nucleus to describe suitably labelled polypeptides in membranes, requiring only little material and short NMR acquisition times.

  10. Antimicrobial peptides of multicellular organisms

    Science.gov (United States)

    Zasloff, Michael

    2002-01-01

    Multicellular organisms live, by and large, harmoniously with microbes. The cornea of the eye of an animal is almost always free of signs of infection. The insect flourishes without lymphocytes or antibodies. A plant seed germinates successfully in the midst of soil microbes. How is this accomplished? Both animals and plants possess potent, broad-spectrum antimicrobial peptides, which they use to fend off a wide range of microbes, including bacteria, fungi, viruses and protozoa. What sorts of molecules are they? How are they employed by animals in their defence? As our need for new antibiotics becomes more pressing, could we design anti-infective drugs based on the design principles these molecules teach us?

  11. Antimicrobial Peptides: Multifunctional Drugs for Different Applications

    Directory of Open Access Journals (Sweden)

    Lea-Jessica Albrecht

    2012-02-01

    Full Text Available Antimicrobial peptides (APs are an important part of the innate immune system in epithelial and non-epithelial surfaces. So far, many different antimicrobial peptides from various families have been discovered in non-vertebrates and vertebrates. They are characterized by antibiotic, antifungal and antiviral activities against a variety of microorganisms. In addition to their role as endogenous antimicrobials, APs participate in multiple aspects of immunity. They are involved in septic and non-septic inflammation, wound repair, angiogenesis, regulation of the adaptive immune system and in maintaining homeostasis. Due to those characteristics AP could play an important role in many practical applications. Limited therapeutic efficiency of current antimicrobial agents and the emerging resistance of pathogens require alternate antimicrobial drugs. The purpose of this review is to highlight recent literature on functions and mechanisms of APs. It also shows their current practical applications as peptide therapeutics and bioactive polymers and discusses the possibilities of future clinical developments.

  12. Diversity of wheat anti-microbial peptides.

    Science.gov (United States)

    Egorov, Tsezi A; Odintsova, Tatyana I; Pukhalsky, Vitaliy A; Grishin, Eugene V

    2005-11-01

    From seeds of Triticum kiharae Dorof. et Migusch., 24 novel anti-microbial peptides were isolated and characterized by a combination of three-step HPLC (affinity, size-exclusion and reversed-phase) with matrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and Edman degradation. Based on sequence similarity and cysteine motifs, partially sequenced peptides were assigned to 7 families: defensins, thionins, lipid-transfer proteins, hevein-like peptides, knottin-like peptides, glycine-rich peptides, and MBP-1 homologs. A novel subfamily of defensins consisting of 6 peptides and a new family of glycine-rich (8 peptides with different repeat motifs) were identified. Three 6-cysteine knottin-like peptides represented by N- and C-terminally truncated variants revealed no sequence homology to any known plant anti-microbial peptides. A new 8-cysteine hevein-like peptide and three 4-cysteine peptides homologous to MBP-1 from maize were isolated. This is the first communication on the occurrence of nearly all families of plant anti-microbial peptides in a single species. PMID:16269343

  13. Role of acetylation and charge in antimicrobial peptides based on human beta-defensin-3.

    Science.gov (United States)

    Papanastasiou, Emilios Andrew; Hua, Quyen; Sandouk, Aline; Son, U Hyon; Christenson, Andrew James; Van Hoek, Monique Louise; Bishop, Barney Michael

    2009-07-01

    Cationic antimicrobial peptides are an evolutionarily ancient and essential element of innate immunity in higher organisms. The precise mechanism by which these peptides exert their antimicrobial activity on bacteria is not well understood. Decapeptides based on the C-terminus of human beta-defensin-3 were designed and evaluated to study the role of charge in defining the antimicrobial activity and selectivity of these peptides against Escherichia coli. Acetylated derivatives of these peptides were prepared in order to further evaluate how positively charged primary amines contribute to potency in these small antimicrobial peptides. These peptides enabled us to explore the relationship between net charge, charge distribution and antimicrobial activity. While the results indicate that net charge is a major factor in antimicrobial activity in these peptides, the actual relationship between charge and potency appears to be more complex.

  14. [Antimicrobial peptide in dentisty. Literature review].

    Science.gov (United States)

    Sato, F Simain; Rompen, E; Heinen, E

    2009-12-01

    The use of antimicrobial substances has contributed to the development of multiple antimicrobial resistances (1), challenging the pharmaceutical industry to develop with new, innovative, and effective molecules. Discovered around 1980, molecules called natural antimicrobial peptides (AMPs) appear to hold great potential for the treatment of infections. These cationic peptides are able to stop the bacterial development and to control infections. The purpose of this review is to help improve the understanding of the way AMPs operate in the context of the development of new cures against viruses, bacteria, and mushrooms found in the human body in general and in the oral cavity in particular. PMID:20143750

  15. [Application on food preservative of antimicrobial peptides].

    Science.gov (United States)

    Zhao, Hongyan; Mu, Yu; Zhao, Baohua

    2009-07-01

    Antimicrobial peptides are an integral component of the innate immune system, it can counteract outer membrane pathogen such as bacteria, fungi, viruses, protozoan and so on. Owing to the sterilization and innocuity, it has the potential to be crude food preservative. In this paper the uses of antibacterial peptides in the food preservative were analyzed.

  16. Antimicrobial Peptides in Toroidal and Cylindrical Pores

    OpenAIRE

    Mihajlovic, Maja; Lazaridis, Themis

    2010-01-01

    Antimicrobial peptides (AMPs) are small, usually cationic peptides, which permeabilize biological membranes. Their mechanism of action is still not well understood. Here we investigate the preference of alamethicin and melittin for pores of different shapes, using molecular dynamics (MD) simulations of the peptides in pre-formed toroidal and cylindrical pores. When an alamethicin hexamer is initially embedded in a cylindrical pore, at the end of the simulation the pore remains cylindrical or ...

  17. Salt-resistant short antimicrobial peptides.

    Science.gov (United States)

    Mohanram, Harini; Bhattacharjya, Surajit

    2016-05-01

    Antimicrobial peptides (AMPs) are promising leads for the development of antibiotics against drug resistant bacterial pathogens. However, in vivo applications of AMPs remain obscure due to salt and serum mediated inactivation. The high cost of chemical synthesis of AMPs also impedes potential clinical application. Consequently, short AMPs resistant toward salt and serum inactivation are desirable for the development of peptide antibiotics. In this work, we designed a 12-residue amphipathic helical peptide RR12 (R-R-L-I-R-L-I-L-R-L-L-R-amide) and two Trp containing analogs of RR12 namely RR12Wpolar (R-R-L-I-W-L-I-L-R-L-L-R-amide), and RR12Whydro (R-R-L-I-R-L-W-L-R-L-L-R-amide). Designed peptides demonstrated potent antibacterial activity; MIC ranging from 2 to 8 μM, in the presence of sodium chloride (150 mM and 300 mM). Antibacterial activity of these peptides was also detected in the presence of human serum. Designed peptides, in particular RR12 and RR12Whydro, were only poorly hemolytic. As a mode of action; these peptides demonstrated efficient permeabilization of bacterial cell membrane and lysis of cell structure. We further investigated interactions of the designed peptides with lipopolysaccharide (LPS), the major component of the outer membrane permeability barrier of Gram-negative bacteria. Designed peptides adopted helical conformations in complex with LPS. Binding of peptides with LPS has yielded dissociation the aggregated structures of LPS. Collectively, these designed peptides hold ability to be developed for salt-resistant antimicrobial compounds. Most importantly, current work provides insights for designing salt-resistant antimicrobial peptides. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 345-356, 2016. PMID:26849911

  18. Antimicrobial peptides in innate immune responses.

    Science.gov (United States)

    Sørensen, Ole E; Borregaard, Niels; Cole, Alexander M

    2008-01-01

    Antimicrobial peptides (AMPs) are ancient effector molecules in the innate immune response of eukaryotes. These peptides are important for the antimicrobial efficacy of phagocytes and for the innate immune response mounted by epithelia of humans and other mammals. AMPs are generated either by de novo synthesis or by proteolytic cleavage from antimicrobially inactive proproteins. Studies of human diseases and animal studies have given important clues to the in vivo role of AMPs. It is now evident that dysregulation of the generation of AMPs in innate immune responses plays a role in certain diseases like Crohn's disease and atopic dermatitis. AMPs are attractive candidates for development of novel antibiotics due to their in vivo activity profile and some peptides may serve as templates for further drug development.

  19. Antimicrobial peptides in innate immune responses

    DEFF Research Database (Denmark)

    Sorensen, O.E.; Borregaard, N.; Cole, A.M.

    2008-01-01

    Antimicrobial peptides (AMPs) are ancient effector molecules in the innate immune response of eukaryotes. These peptides are important for the antimicrobial efficacy of phagocytes and for the innate immune response mounted by epithelia of humans and other mammals. AMPs are generated either by de...... novo synthesis or by proteolytic cleavage from antimicrobially inactive proproteins. Studies of human diseases and animal studies have given important clues to the in vivo role of AMPs. It is now evident that dysregulation of the generation of AMPs in innate immune responses plays a role in certain...... diseases like Crohn's disease and atopic dermatitis. AMPs are attractive candidates for development of novel antibiotics due to their in vivo activity profile and some peptides may serve as templates for further drug development Udgivelsesdato: 2008...

  20. Toxins and antimicrobial peptides: interactions with membranes

    Science.gov (United States)

    Schlamadinger, Diana E.; Gable, Jonathan E.; Kim, Judy E.

    2009-08-01

    The innate immunity to pathogenic invasion of organisms in the plant and animal kingdoms relies upon cationic antimicrobial peptides (AMPs) as the first line of defense. In addition to these natural peptide antibiotics, similar cationic peptides, such as the bee venom toxin melittin, act as nonspecific toxins. Molecular details of AMP and peptide toxin action are not known, but the universal function of these peptides to disrupt cell membranes of pathogenic bacteria (AMPs) or a diverse set of eukaryotes and prokaryotes (melittin) is widely accepted. Here, we have utilized spectroscopic techniques to elucidate peptide-membrane interactions of alpha-helical human and mouse AMPs of the cathelicidin family as well as the peptide toxin melittin. The activity of these natural peptides and their engineered analogs was studied on eukaryotic and prokaryotic membrane mimics consisting of peptide potency, was monitored with a sensitive fluorescence leakage assay. Detailed molecular information on peptidemembrane interactions and peptide structure was further gained through vibrational spectroscopy combined with circular dichroism. Finally, steady-state fluorescence experiments yielded insight into the local environment of native or engineered tryptophan residues in melittin and human cathelicidin embedded in bilayer vesicles. Collectively, our results provide clues to the functional structures of the engineered and toxic peptides and may impact the design of synthetic antibiotic peptides that can be used against the growing number of antibiotic-resistant pathogens.

  1. Antimicrobial Peptides in Innate Immunity against Mycobacteria.

    Science.gov (United States)

    Shin, Dong-Min; Jo, Eun-Kyeong

    2011-10-01

    Antimicrobial peptides/proteins are ancient and naturallyoccurring antibiotics in innate immune responses in a variety of organisms. Additionally, these peptides have been recognized as important signaling molecules in regulation of both innate and adaptive immunity. During mycobacterial infection, antimicrobial peptides including cathelicidin, defensin, and hepcidin have antimicrobial activities against mycobacteria, making them promising candidates for future drug development. Additionally, antimicrobial peptides act as immunomodulators in infectious and inflammatory conditions. Multiple crucial functions of cathelicidins in antimycobacterial immune defense have been characterized not only in terms of direct killing of mycobacteria but also as innate immune regulators, i.e., in secretion of cytokines and chemokines, and mediating autophagy activation. Defensin families are also important during mycobacterial infection and contribute to antimycobacterial defense and inhibition of mycobacterial growth both in vitro and in vivo. Hepcidin, although its role in mycobacterial infection has not yet been characterized, exerts antimycobacterial effects in activated macrophages. The present review focuses on recent efforts to elucidate the roles of host defense peptides in innate immunity to mycobacteria.

  2. From antimicrobial to anticancer peptides. A review.

    OpenAIRE

    Diana eGaspar; A. Salomé eVeiga; Miguel A.R.B. eCastanho

    2013-01-01

    Antimicrobial peptides (AMPs) are part of the innate immune defense mechanism of many organisms. Although AMPs have been essentially studied and developed as potential alternatives for fighting infectious diseases, their use as anticancer peptides (ACPs) in cancer therapy either alone or in combination with other conventional drugs has been regarded as a therapeutic strategy to explore. As human cancer remains a cause of high morbidity and mortality worldwide, an urgent need of new, selective...

  3. Computer-Aided Design of Antimicrobial Peptides

    DEFF Research Database (Denmark)

    Fjell, Christopher D.; Hancock, Robert E.W.; Jenssen, Håvard

    2010-01-01

    An increasing number of reported cases of drug resistant Staphylococcus aureus and Pseudomonas aeruginosa, demonstrate the urgent need for new therapeutics that are effective against such and other multi-drug resistant bacteria. Antimicrobial peptides have for two decades now been looked upon as...

  4. Quantitative studies of antimicrobial peptide-lipid membrane interactions

    DEFF Research Database (Denmark)

    Kristensen, Kasper

    induced by mastoparan X, melittin and magainin 2 from POPC/POPG (3:1) large unilamellar lipid vesicles. The results show that on the single-vesicle level, all three peptides induce heterogenous leakage in the sense that they induce complete emptying of some vesicles and only partly emptying of other......The increasing occurrence of multi-drug-resistant bacteria poses a serious threat to modern society. Therefore, novel types of anti-infective therapeutics are highly warranted. Antimicrobial peptides are a class of naturally occurring host-defense molecules that potentially might be developed...... that it can be used to quantify antimicrobial peptide-induced leakage of fluorescent markers from large unilamellar lipid vesicles in solution. For that purpose, we derive the mathematical framework required to calculate leakage from the FCS data, and we identify a number of experimental pitfalls that might...

  5. Design and Application of Antimicrobial Peptide Conjugates

    Directory of Open Access Journals (Sweden)

    Andre Reinhardt

    2016-05-01

    Full Text Available Antimicrobial peptides (AMPs are an interesting class of antibiotics characterized by their unique antibiotic activity and lower propensity for developing resistance compared to common antibiotics. They belong to the class of membrane-active peptides and usually act selectively against bacteria, fungi and protozoans. AMPs, but also peptide conjugates containing AMPs, have come more and more into the focus of research during the last few years. Within this article, recent work on AMP conjugates is reviewed. Different aspects will be highlighted as a combination of AMPs with antibiotics or organometallic compounds aiming to increase antibacterial activity or target selectivity, conjugation with photosensitizers for improving photodynamic therapy (PDT or the attachment to particles, to name only a few. Owing to the enormous resonance of antimicrobial conjugates in the literature so far, this research topic seems to be very attractive to different scientific fields, like medicine, biology, biochemistry or chemistry.

  6. Antimicrobial peptides in echinoderm host defense.

    Science.gov (United States)

    Li, Chun; Blencke, Hans-Matti; Haug, Tor; Stensvåg, Klara

    2015-03-01

    Antimicrobial peptides (AMPs) are important effector molecules in innate immunity. Here we briefly summarize characteristic traits of AMPs and their mechanisms of antimicrobial activity. Echinoderms live in a microbe-rich marine environment and are known to express a wide range of AMPs. We address two novel AMP families from coelomocytes of sea urchins: cysteine-rich AMPs (strongylocins) and heterodimeric AMPs (centrocins). These peptide families have conserved preprosequences, are present in both adults and pluteus stage larvae, have potent antimicrobial properties, and therefore appear to be important innate immune effectors. Strongylocins have a unique cysteine pattern compared to other cysteine-rich peptides, which suggests a novel AMP folding pattern. Centrocins and SdStrongylocin 2 contain brominated tryptophan residues in their native form. This review also includes AMPs isolated from other echinoderms, such as holothuroidins, fragments of beta-thymosin, and fragments of lectin (CEL-III). Echinoderm AMPs are crucial molecules for the understanding of echinoderm immunity, and their potent antimicrobial activity makes them potential precursors of novel drug leads. PMID:25445901

  7. Antimicrobial peptides in echinoderm host defense.

    Science.gov (United States)

    Li, Chun; Blencke, Hans-Matti; Haug, Tor; Stensvåg, Klara

    2015-03-01

    Antimicrobial peptides (AMPs) are important effector molecules in innate immunity. Here we briefly summarize characteristic traits of AMPs and their mechanisms of antimicrobial activity. Echinoderms live in a microbe-rich marine environment and are known to express a wide range of AMPs. We address two novel AMP families from coelomocytes of sea urchins: cysteine-rich AMPs (strongylocins) and heterodimeric AMPs (centrocins). These peptide families have conserved preprosequences, are present in both adults and pluteus stage larvae, have potent antimicrobial properties, and therefore appear to be important innate immune effectors. Strongylocins have a unique cysteine pattern compared to other cysteine-rich peptides, which suggests a novel AMP folding pattern. Centrocins and SdStrongylocin 2 contain brominated tryptophan residues in their native form. This review also includes AMPs isolated from other echinoderms, such as holothuroidins, fragments of beta-thymosin, and fragments of lectin (CEL-III). Echinoderm AMPs are crucial molecules for the understanding of echinoderm immunity, and their potent antimicrobial activity makes them potential precursors of novel drug leads.

  8. Classification of antimicrobial peptides with imbalanced datasets

    Science.gov (United States)

    Camacho, Francy L.; Torres, Rodrigo; Ramos Pollán, Raúl

    2015-12-01

    In the last years, pattern recognition has been applied to several fields for solving multiple problems in science and technology as for example in protein prediction. This methodology can be useful for prediction of activity of biological molecules, e.g. for determination of antimicrobial activity of synthetic and natural peptides. In this work, we evaluate the performance of different physico-chemical properties of peptides (descriptors groups) in the presence of imbalanced data sets, when facing the task of detecting whether a peptide has antimicrobial activity. We evaluate undersampling and class weighting techniques to deal with the class imbalance with different classification methods and descriptor groups. Our classification model showed an estimated precision of 96% showing that descriptors used to codify the amino acid sequences contain enough information to correlate the peptides sequences with their antimicrobial activity by means of learning machines. Moreover, we show how certain descriptor groups (pseudoaminoacid composition type I) work better with imbalanced datasets while others (dipeptide composition) work better with balanced ones.

  9. Computer-Aided Design of Antimicrobial Peptides

    DEFF Research Database (Denmark)

    Fjell, Christopher D.; Hancock, Robert E.W.; Jenssen, Håvard

    2010-01-01

    chemical parameters with biological activities of the peptide, using statistical methods. In this review we will discuss two different in silico strategies of computer-aided antibacterial peptide design, a linear correlation model build as an extension of traditional principal component analysis (PCA......) and a non-linear artificial neural network model. Studies on structurally diverse peptides, have concluded that the PCA derived model are able to guide the antibacterial peptide design in a meaningful way, however requiring rather a high homology between the peptides in the test-set and the in silico...

  10. Therapeutic antimicrobial peptides may compromise natural immunity.

    Science.gov (United States)

    Habets, Michelle G J L; Brockhurst, Michael A

    2012-06-23

    Antimicrobial peptides (AMPs) have been proposed as a promising new class of antimicrobials despite warnings that therapeutic use could drive the evolution of pathogens resistant to our own immunity peptides. Using experimental evolution, we demonstrate that Staphylococcus aureus rapidly evolved resistance to pexiganan, a drug-candidate for diabetic leg ulcer infections. Evolved resistance was costly in terms of impaired growth rate, but costs-of-resistance were completely ameliorated by compensatory adaptation. Crucially, we show that, in some populations, experimentally evolved resistance to pexiganan provided S. aureus with cross-resistance to human-neutrophil-defensin-1, a key component of the innate immune response to infection. This unintended consequence of therapeutic use could drastically undermine our innate immune system's ability to control and clear microbial infections. Our results therefore highlight grave potential risks of AMP therapies, with implications for their development.

  11. The Design and Construction of K11: A Novel α-Helical Antimicrobial Peptide

    Directory of Open Access Journals (Sweden)

    Huang Jin-Jiang

    2012-01-01

    Full Text Available Amphipathic α-helical antimicrobial peptides comprise a class of broad-spectrum agents that are used against pathogens. We designed a series of antimicrobial peptides, CP-P (KWKSFIKKLTSKFLHLAKKF and its derivatives, and determined their minimum inhibitory concentrations (MICs against Pseudomonas aeruginosa, their minimum hemolytic concentrations (MHCs for human erythrocytes, and the Therapeutic Index (MHC/MIC ratio. We selected the derivative peptide K11, which had the highest therapeutic index (320 among the tested peptides, to determine the MICs against Gram-positive and Gram-negative bacteria and 22 clinical isolates including Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Klebsiella pneumonia. K11 exhibited low MICs (less than 10 μg/mL and broad-spectrum antimicrobial activity, especially against clinically isolated drug-resistant pathogens. Therefore, these results indicate that K11 is a promising candidate antimicrobial peptide for further studies.

  12. Pro-Moieties of Antimicrobial Peptide Prodrugs

    Directory of Open Access Journals (Sweden)

    Eanna Forde

    2015-01-01

    Full Text Available Antimicrobial peptides (AMPs are a promising class of antimicrobial agents that have been garnering increasing attention as resistance renders many conventional antibiotics ineffective. Extensive research has resulted in a large library of highly-active AMPs. However, several issues serve as an impediment to their clinical development, not least the issue of host toxicity. An approach that may allow otherwise cytotoxic AMPs to be used is to deliver them as a prodrug, targeting antimicrobial activity and limiting toxic effects on the host. The varied library of AMPs is complemented by a selection of different possible pro-moieties, each with their own characteristics. This review deals with the different pro-moieties that have been used with AMPs and discusses the merits of each.

  13. Peptide design for antimicrobial and immunomodulatory applications.

    Science.gov (United States)

    Haney, Evan F; Hancock, Robert E W

    2013-11-01

    The increasing threat of antibiotic resistance in pathogenic bacteria and the dwindling supply of antibiotics available to combat these infections poses a significant threat to human health throughout the world. Antimicrobial peptides (AMPs) have long been touted as the next generation of antibiotics capable of filling the anti-infective void. Unfortunately, peptide-based antibiotics have yet to realize their potential as novel pharmaceuticals, in spite of the immense number of known AMP sequences and our improved understanding of their antibacterial mechanism of action. Recently, the immunomodulatory properties of certain AMPs have become appreciated. The ability of small synthetic peptides to protect against infection in vivo has demonstrated that modulation of the innate immune response is an effective strategy to further develop peptides as novel anti-infectives. This review focuses on the screening methods that have been used to assess novel peptide sequences for their antibacterial and immunomodulatory properties. It will also examine how we have progressed in our ability to identify and optimize peptides with desired biological characteristics and enhanced therapeutic potential. In addition, the current challenges to the development of peptides as anti-infectives are examined and the strategies being used to overcome these issues are discussed.

  14. Antimicrobial peptides: a review of how peptide structure impacts antimicrobial activity

    Science.gov (United States)

    Soares, Jason W.; Mello, Charlene M.

    2004-03-01

    Antimicrobial peptides (AMPs) have been discovered in insects, mammals, reptiles, and plants to protect against microbial infection. Many of these peptides have been isolated and studied exhaustively to decipher the molecular mechanisms that impart protection against infectious bacteria, fungi, and viruses. Unfortunately, the molecular mechanisms are still being debated within the scientific community but valuable clues have been obtained through structure/function relationship studies1. Biophysical studies have revealed that cecropins, isolated from insects and pigs, exhibit random structure in solution but undergo a conformational change to an amphipathic α-helix upon interaction with a membrane surface2. The lack of secondary structure in solution results in an extremely durable peptide able to survive exposure to high temperatures, organic solvents and incorporation into fibers and films without compromising antibacterial activity. Studies to better understand the antimicrobial action of cecropins and other AMPs have provided insight into the importance of peptide sequence and structure in antimicrobial activities. Therefore, enhancing our knowledge of how peptide structure imparts function may result in customized peptide sequences tailored for specific applications such as targeted cell delivery systems, novel antibiotics and food preservation additives. This review will summarize the current state of knowledge with respect to cell binding and antimicrobial activity of AMPs focusing primarily upon cecropins.

  15. Chromogranin A-derived peptides are involved in innate immunity.

    Science.gov (United States)

    Aslam, R; Atindehou, M; Lavaux, T; Haïkel, Y; Schneider, F; Metz-Boutigue, M-H

    2012-01-01

    New endogenous antimicrobial peptides (AMPs) derived from chromogranin A (CgA) are secreted by nervous, endocrine and immune cells during stress. They display antimicrobial activities by lytic effects at micromolar range using a pore-forming mechanism against Gram-positive bacteria, filamentous fungi and yeasts. These AMPs can also penetrate quickly into neutrophils (without lytic effects), where, similarly to "cell penetrating peptides", they interact with cytoplasmic calmodulin, and induce calcium influx via Store Operated Channels therefore triggering neutrophils activation. Staphylococcus aureus and Salmonella enteritis are bacteria responsible for severe infections. We investigated here the effects of S. aureus and S. enteritis bacterial proteases on CgA-derived peptides and evaluated their antimicrobial activities. We showed that the Glu-C protease produced by S. aureus V8 induces the loss of the AMPs antibacterial activities and produces new antifungal peptides. In addition, four antimicrobial CGA-derived peptides (chromofungin, procatestatin, human/bovine catestatin) are degraded when treated with bacterial supernatants from S. aureus and S. enteritis, whereas, cateslytin, the short active form of catestatin, resists to this degradation. Finally, we demonstrate that several antimicrobial CgA-derived peptides are able to act synergistically with antibiotics against bacteria and fungi indicating their roles in innate defense.

  16. Susceptibility to Infectious Diseases Based on Antimicrobial Peptide Production▿

    Science.gov (United States)

    Rivas-Santiago, Bruno; Serrano, Carmen J.; Enciso-Moreno, J. Antonio

    2009-01-01

    In the last few years, the great impact of antimicrobial peptides on infectious disease susceptibility and natural resistance has been reported. In some cases, susceptibility to diseases is related to antimicrobial peptide polymorphisms and gene copy numbers, but for the vast majority of infectious diseases, these phenomena need to be elucidated. This review is focused on the current knowledge about susceptibility and resistance conferred by genetic variations in antimicrobial peptide expression in infectious diseases. PMID:19703980

  17. Susceptibility to infectious diseases based on antimicrobial peptide production.

    Science.gov (United States)

    Rivas-Santiago, Bruno; Serrano, Carmen J; Enciso-Moreno, J Antonio

    2009-11-01

    In the last few years, the great impact of antimicrobial peptides on infectious disease susceptibility and natural resistance has been reported. In some cases, susceptibility to diseases is related to antimicrobial peptide polymorphisms and gene copy numbers, but for the vast majority of infectious diseases, these phenomena need to be elucidated. This review is focused on the current knowledge about susceptibility and resistance conferred by genetic variations in antimicrobial peptide expression in infectious diseases.

  18. Snake Cathelicidin NA-CATH and Smaller Helical Antimicrobial Peptides Are Effective against Burkholderia thailandensis.

    Directory of Open Access Journals (Sweden)

    Ryan J Blower

    Full Text Available Burkholderia thailandensis is a Gram-negative soil bacterium used as a model organism for B. pseudomallei, the causative agent of melioidosis and an organism classified category B priority pathogen and a Tier 1 select agent for its potential use as a biological weapon. Burkholderia species are reportedly "highly resistant" to antimicrobial agents, including cyclic peptide antibiotics, due to multiple resistance systems, a hypothesis we decided to test using antimicrobial (host defense peptides. In this study, a number of cationic antimicrobial peptides (CAMPs were tested in vitro against B. thailandensis for both antimicrobial activity and inhibition of biofilm formation. Here, we report that the Chinese cobra (Naja atra cathelicidin NA-CATH was significantly antimicrobial against B. thailandensis. Additional cathelicidins, including the human cathelicidin LL-37, a sheep cathelicidin SMAP-29, and some smaller ATRA peptide derivatives of NA-CATH were also effective. The D-enantiomer of one small peptide (ATRA-1A was found to be antimicrobial as well, with EC50 in the range of the L-enantiomer. Our results also demonstrate that human alpha-defensins (HNP-1 & -2 and a short beta-defensin-derived peptide (Peptide 4 of hBD-3 were not bactericidal against B. thailandensis. We also found that the cathelicidin peptides, including LL-37, NA-CATH, and SMAP-29, possessed significant ability to prevent biofilm formation of B. thailandensis. Additionally, we show that LL-37 and its D-enantiomer D-LL-37 can disperse pre-formed biofilms. These results demonstrate that although B. thailandensis is highly resistant to many antibiotics, cyclic peptide antibiotics such as polymyxin B, and defensing peptides, some antimicrobial peptides including the elapid snake cathelicidin NA-CATH exert significant antimicrobial and antibiofilm activity towards B. thailandensis.

  19. Snake Cathelicidin NA-CATH and Smaller Helical Antimicrobial Peptides Are Effective against Burkholderia thailandensis.

    Science.gov (United States)

    Blower, Ryan J; Barksdale, Stephanie M; van Hoek, Monique L

    2015-01-01

    Burkholderia thailandensis is a Gram-negative soil bacterium used as a model organism for B. pseudomallei, the causative agent of melioidosis and an organism classified category B priority pathogen and a Tier 1 select agent for its potential use as a biological weapon. Burkholderia species are reportedly "highly resistant" to antimicrobial agents, including cyclic peptide antibiotics, due to multiple resistance systems, a hypothesis we decided to test using antimicrobial (host defense) peptides. In this study, a number of cationic antimicrobial peptides (CAMPs) were tested in vitro against B. thailandensis for both antimicrobial activity and inhibition of biofilm formation. Here, we report that the Chinese cobra (Naja atra) cathelicidin NA-CATH was significantly antimicrobial against B. thailandensis. Additional cathelicidins, including the human cathelicidin LL-37, a sheep cathelicidin SMAP-29, and some smaller ATRA peptide derivatives of NA-CATH were also effective. The D-enantiomer of one small peptide (ATRA-1A) was found to be antimicrobial as well, with EC50 in the range of the L-enantiomer. Our results also demonstrate that human alpha-defensins (HNP-1 & -2) and a short beta-defensin-derived peptide (Peptide 4 of hBD-3) were not bactericidal against B. thailandensis. We also found that the cathelicidin peptides, including LL-37, NA-CATH, and SMAP-29, possessed significant ability to prevent biofilm formation of B. thailandensis. Additionally, we show that LL-37 and its D-enantiomer D-LL-37 can disperse pre-formed biofilms. These results demonstrate that although B. thailandensis is highly resistant to many antibiotics, cyclic peptide antibiotics such as polymyxin B, and defensing peptides, some antimicrobial peptides including the elapid snake cathelicidin NA-CATH exert significant antimicrobial and antibiofilm activity towards B. thailandensis. PMID:26196513

  20. Antifungal effect of antimicrobial peptides (AMPs LR14) derived from Lactobacillus plantarum strain LR/14 and their applications in prevention of grain spoilage.

    Science.gov (United States)

    Gupta, Ruchi; Srivastava, Sheela

    2014-09-01

    The concern for food safety has led to an increased interest in the development of novel antimicrobials. Keeping this aim in mind, we have investigated the antifungal effect of antimicrobial peptides (AMPs LR14) produced by Lactobacillus plantarum strain LR/14 against four spoilage fungi, namely, Aspergillus niger, Rhizopus stolonifer, Mucor racemosus and Penicillium chrysogenum. Interestingly, all the four fungi were inhibited, suggesting that AMPs LR14 exhibited anti-fungal property. The peptides inhibited both, the spore germination and hyphal growth, however, the former stage was found to be more susceptible. The hyphal extensions were also inhibited in a dose-dependent manner. Viability test of treated spores confirmed the fungicidal activity of AMPs LR14. AMPs LR14 were also studied for the prevention of wheat grain spoilage under storage. Unhygienic conditions in damp godowns and store-houses, lead to loss of food grains and make them unfit for human consumption due to microbial deterioration. The treatment of wheat seeds with AMPs LR14 prevented fungal growth even after a prolonged storage under laboratory conditions for ∼2.5 years. The carbohydrate and protein content of the AMPs LR14-treated seeds denoted no significant loss, but the seed viability was affected as germination was retarded. Such studies have not been reported for any bacteriocin/AMP to the best of our knowledge.

  1. Resistance to Antimicrobial Peptides in Vibrios

    Directory of Open Access Journals (Sweden)

    Delphine Destoumieux-Garzón

    2014-10-01

    Full Text Available Vibrios are associated with a broad diversity of hosts that produce antimicrobial peptides (AMPs as part of their defense against microbial infections. In particular, vibrios colonize epithelia, which function as protective barriers and express AMPs as a first line of chemical defense against pathogens. Recent studies have shown they can also colonize phagocytes, key components of the animal immune system. Phagocytes infiltrate infected tissues and use AMPs to kill the phagocytosed microorganisms intracellularly, or deliver their antimicrobial content extracellularly to circumvent tissue infection. We review here the mechanisms by which vibrios have evolved the capacity to evade or resist the potent antimicrobial defenses of the immune cells or tissues they colonize. Among their strategies to resist killing by AMPs, primarily vibrios use membrane remodeling mechanisms. In particular, some highly resistant strains substitute hexaacylated Lipid A with a diglycine residue to reduce their negative surface charge, thereby lowering their electrostatic interactions with cationic AMPs. As a response to envelope stress, which can be induced by membrane-active agents including AMPs, vibrios also release outer membrane vesicles to create a protective membranous shield that traps extracellular AMPs and prevents interaction of the peptides with their own membranes. Finally, once AMPs have breached the bacterial membrane barriers, vibrios use RND efflux pumps, similar to those of other species, to transport AMPs out of their cytoplasmic space.

  2. Avian Antimicrobial Host Defense Peptides: From Biology to Therapeutic Applications

    Directory of Open Access Journals (Sweden)

    Guolong Zhang

    2014-02-01

    Full Text Available Host defense peptides (HDPs are an important first line of defense with antimicrobial and immunomoduatory properties. Because they act on the microbial membranes or host immune cells, HDPs pose a low risk of triggering microbial resistance and therefore, are being actively investigated as a novel class of antimicrobials and vaccine adjuvants. Cathelicidins and β-defensins are two major families of HDPs in avian species. More than a dozen HDPs exist in birds, with the genes in each HDP family clustered in a single chromosomal segment, apparently as a result of gene duplication and diversification. In contrast to their mammalian counterparts that adopt various spatial conformations, mature avian cathelicidins are mostly α-helical. Avian β-defensins, on the other hand, adopt triple-stranded β-sheet structures similar to their mammalian relatives. Besides classical β-defensins, a group of avian-specific β-defensin-related peptides, namely ovodefensins, exist with a different six-cysteine motif. Like their mammalian counterparts, avian cathelicidins and defensins are derived from either myeloid or epithelial origin expressed in a majority of tissues with broad-spectrum antibacterial and immune regulatory activities. Structure-function relationship studies with several avian HDPs have led to identification of the peptide analogs with potential for use as antimicrobials and vaccine adjuvants. Dietary modulation of endogenous HDP synthesis has also emerged as a promising alternative approach to disease control and prevention in chickens.

  3. Differential activity of innate defense antimicrobial peptides against Nocardia species

    Directory of Open Access Journals (Sweden)

    Wagner Dirk

    2010-02-01

    Full Text Available Abstract Background Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs in innate defense against Nocardia, the activity of human α-defensins human neutrophil peptides (HNPs 1-3, human β-defensin (hBD-3 and cathelicidin LL-37 as well as bovine β-defensins lingual and tracheal antimicrobial peptides (LAP, TAP and bovine neutrophil-derived indolicidin against four important Nocardia species was investigated. Results Whereas N. farcinica ATCC 3318 and N. nova ATCC 33726 were found to be susceptible to all investigated human and bovine AMPs, N. asteroides ATCC 19247 was killed exclusively by neutrophil-derived human α-defensins HNP 1-3 and bovine indolicidin. N. brasiliensis ATCC 19296 was found to exhibit complete resistance to investigated human AMPs and to be susceptible only to bovine indolicidin. Conclusion Selected AMPs are capable to contribute to the first line of defense against Nocardia, yet, susceptibility appears to vary across different Nocardia species. Obtained results of neutrophil-derived AMPs to possess the broadest antinocardial spectrum are remarkable, since nocardiosis is characterized by a neutrophil-rich infiltrate in vivo.

  4. Sap Transporter Mediated Import and Subsequent Degradation of Antimicrobial Peptides in Haemophilus

    OpenAIRE

    Shelton, Catherine L.; Raffel, Forrest K.; Wandy L Beatty; Johnson, Sara M.; Mason, Kevin M.

    2011-01-01

    Antimicrobial peptides (AMPs) contribute to host innate immune defense and are a critical component to control bacterial infection. Nontypeable Haemophilus influenzae (NTHI) is a commensal inhabitant of the human nasopharyngeal mucosa, yet is commonly associated with opportunistic infections of the upper and lower respiratory tracts. An important aspect of NTHI virulence is the ability to avert bactericidal effects of host-derived antimicrobial peptides (AMPs). The Sap (sensitivity to antimic...

  5. Fatty acid conjugation enhances the activities of antimicrobial peptides.

    Science.gov (United States)

    Li, Zhining; Yuan, Penghui; Xing, Meng; He, Zhumei; Dong, Chuanfu; Cao, Yongchang; Liu, Qiuyun

    2013-04-01

    Antimicrobial peptides are small molecules that play a crucial role in innate immunity in multi-cellular organisms, and usually expressed and secreted constantly at basal levels to prevent infection, but local production can be augmented upon an infection. The clock is ticking as rising antibiotic abuse has led to the emergence of many drug resistance bacteria. Due to their broad spectrum antibiotic and antifungal activities as well as anti-viral and anti-tumor activities, efforts are being made to develop antimicrobial peptides into future microbial agents. This article describes some of the recent patents on antimicrobial peptides with fatty acid conjugation. Potency and selectivity of antimicrobial peptide can be modulated with fatty acid tails of variable length. Interaction between membranes and antimicrobial peptides was affected by fatty acid conjugation. At concentrations above the critical miscelle concentration (CMC), propensity of solution selfassembly hampered binding of the peptide to cell membranes. Overall, fatty acid conjugation has enhanced the activities of antimicrobial peptides, and occasionally it rendered inactive antimicrobial peptides to be bioactive. Antimicrobial peptides can not only be used as medicine but also as food additives.

  6. Plant antimicrobial peptides as potential anticancer agents.

    Science.gov (United States)

    Guzmán-Rodríguez, Jaquelina Julia; Ochoa-Zarzosa, Alejandra; López-Gómez, Rodolfo; López-Meza, Joel E

    2015-01-01

    Antimicrobial peptides (AMPs) are part of the innate immune defense mechanism of many organisms and are promising candidates to treat infections caused by pathogenic bacteria to animals and humans. AMPs also display anticancer activities because of their ability to inactivate a wide range of cancer cells. Cancer remains a cause of high morbidity and mortality worldwide. Therefore, the development of methods for its control is desirable. Attractive alternatives include plant AMP thionins, defensins, and cyclotides, which have anticancer activities. Here, we provide an overview of plant AMPs anticancer activities, with an emphasis on their mode of action, their selectivity, and their efficacy.

  7. Interaction of antimicrobial peptides with lipid membranes

    International Nuclear Information System (INIS)

    This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar phases. POPE forms lamellar phases at low temperatures that upon heating transform into a highly curved inverse hexagonal phase. Insertion of the peptide induced inverse bicontinuous cubic phases which are an ideal compromise between the curvature stress and the packing frustration. Melittin usually induced a mixture of two cubic phases, Im3m and Pn3m, with a ratio of lattice parameters close to 1.279, related to the underlying minimal surfaces. They formed during the lamellar to hexagonal phase transition and persisted during cooling till the onset of the gel phase. The phases formed at different lipid-to-peptide ratios had very similar lattice parameters. Epitaxial relationships existed between coexisting cubic phases and hexagonal or lamellar phases due to confinement of all phases to an onion vesicle, a vesicle with several layers consisting of different lipid phases. Alamethicin induced the same cubic phases, although their formation and lattice parameters were dependent on the peptide concentration. The cubic phases formed during heating from the lamellar phase and their onset

  8. Interaction of antimicrobial peptides with lipid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hanulova, Maria

    2008-12-15

    This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar phases. POPE forms lamellar phases at low temperatures that upon heating transform into a highly curved inverse hexagonal phase. Insertion of the peptide induced inverse bicontinuous cubic phases which are an ideal compromise between the curvature stress and the packing frustration. Melittin usually induced a mixture of two cubic phases, Im3m and Pn3m, with a ratio of lattice parameters close to 1.279, related to the underlying minimal surfaces. They formed during the lamellar to hexagonal phase transition and persisted during cooling till the onset of the gel phase. The phases formed at different lipid-to-peptide ratios had very similar lattice parameters. Epitaxial relationships existed between coexisting cubic phases and hexagonal or lamellar phases due to confinement of all phases to an onion vesicle, a vesicle with several layers consisting of different lipid phases. Alamethicin induced the same cubic phases, although their formation and lattice parameters were dependent on the peptide concentration. The cubic phases formed during heating from the lamellar phase and their onset

  9. Pyrrhocoricin, a proline-rich antimicrobial peptide derived from insect, inhibits the translation process in the cell-free Escherichia coli protein synthesis system.

    Science.gov (United States)

    Taniguchi, Masayuki; Ochiai, Akihito; Kondo, Hiroshi; Fukuda, Shun; Ishiyama, Yohei; Saitoh, Eiichi; Kato, Tetsuo; Tanaka, Takaaki

    2016-05-01

    Previous studies have shown that pyrrhocoricin, a proline-rich antimicrobial peptide (PrAMP), killed sensitive species in a dose-dependent manner by specifically binding to DnaK. Here, on the basis of the finding that DnaK-deficient Escherichia coli strains are susceptible to PrAMPs, we used pyrrhocoricin to investigate internal targets other than DnaK. Using conventional antibiotics (bleomycin, streptomycin, and fosfomycin) that have known modes of action, first, we validated the availability of an assay using a cell-free rapid translation system (RTS), which is an in vitro protein synthesis system based on E. coli lysate, for evaluating inhibition of protein synthesis. We found that, similarly to bleomycin and streptomycin, pyrrhocoricin inhibited GFP synthesis in RTS in a concentration-dependent manner. In addition, blockage of transcription and translation steps in RTS was individually estimated using RT-PCR after gene expression to determine mRNA products and using sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine the amounts of GFP expressed from purified mRNA, respectively. The results demonstrated that this inhibition of GFP synthesis by pyrrhocoricin did not occur at the transcription step but rather at the translation step, in a manner similar to that of GFP synthesis by streptomycin, an inhibitor of the translation step by causing misreading of tRNA. These results suggest that RTS is a powerful assay system for determining if antimicrobial peptides inhibit protein synthesis and its transcription and/or translation steps. This is the first study to have shown that pyrrhocoricin inhibited protein synthesis by specifically repressing the translation step. PMID:26472128

  10. DAMPD: A manually curated antimicrobial peptide database

    KAUST Repository

    Seshadri Sundararajan, Vijayaraghava

    2011-11-21

    The demand for antimicrobial peptides (AMPs) is rising because of the increased occurrence of pathogens that are tolerant or resistant to conventional antibiotics. Since naturally occurring AMPs could serve as templates for the development of new anti-infectious agents to which pathogens are not resistant, a resource that contains relevant information on AMP is of great interest. To that extent, we developed the Dragon Antimicrobial Peptide Database (DAMPD, http://apps.sanbi.ac.za/dampd) that contains 1232 manually curated AMPs. DAMPD is an update and a replacement of the ANTIMIC database. In DAMPD an integrated interface allows in a simple fashion querying based on taxonomy, species, AMP family, citation, keywords and a combination of search terms and fields (Advanced Search). A number of tools such as Blast, ClustalW, HMMER, Hydrocalculator, SignalP, AMP predictor, as well as a number of other resources that provide additional information about the results are also provided and integrated into DAMPD to augment biological analysis of AMPs. The Author(s) 2011. Published by Oxford University Press.

  11. Biofilm Induced Tolerance Towards Antimicrobial Peptides

    DEFF Research Database (Denmark)

    Folkesson, Anders; Haagensen, Janus Anders Juul; Zampaloni, Claudia;

    2008-01-01

    Increased tolerance to antimicrobial agents is thought to be an important feature of microbes growing in biofilms. We address the question of how biofilm organization affects antibiotic susceptibility. We established Escherichia coli biofilms with differential structural organization due...... to the presence of IncF plasmids expressing altered forms of the transfer pili in two different biofilm model systems. The mature biofilms were subsequently treated with two antibiotics with different molecular targets, the peptide antibiotic colistin and the fluoroquinolone ciprofloxacin. The dynamics...... of microbial killing were monitored by viable count determination, and confocal laser microscopy. Strains forming structurally organized biofilms show an increased bacterial survival when challenged with colistin, compared to strains forming unstructured biofilms. The increased survival is due to genetically...

  12. Coleopteran Antimicrobial Peptides: Prospects for Clinical Applications

    Directory of Open Access Journals (Sweden)

    Monde Ntwasa

    2012-01-01

    Full Text Available Antimicrobial peptides (AMPs are activated in response to septic injury and have important roles in vertebrate and invertebrate immune systems. AMPs act directly against pathogens and have both wound healing and antitumor activities. Although coleopterans comprise the largest and most diverse order of eukaryotes and occupy an earlier branch than Drosophila in the holometabolous lineage of insects, their immune system has not been studied extensively. Initial research reports, however, indicate that coleopterans possess unique immune response mechanisms, and studies of these novel mechanisms may help to further elucidate innate immunity. Recently, the complete genome sequence of Tribolium was published, boosting research on coleopteran immunity and leading to the identification of Tribolium AMPs that are shared by Drosophila and mammals, as well as other AMPs that are unique. AMPs have potential applicability in the development of vaccines. Here, we review coleopteran AMPs, their potential impact on clinical medicine, and the molecular basis of immune defense.

  13. Distinct Profiling of Antimicrobial Peptide Families

    KAUST Repository

    Khamis, Abdullah M.

    2014-11-10

    Motivation: The increased prevalence of multi-drug resistant (MDR) pathogens heightens the need to design new antimicrobial agents. Antimicrobial peptides (AMPs) exhibit broad-spectrum potent activity against MDR pathogens and kills rapidly, thus giving rise to AMPs being recognized as a potential substitute for conventional antibiotics. Designing new AMPs using current in-silico approaches is, however, challenging due to the absence of suitable models, large number of design parameters, testing cycles, production time and cost. To date, AMPs have merely been categorized into families according to their primary sequences, structures and functions. The ability to computationally determine the properties that discriminate AMP families from each other could help in exploring the key characteristics of these families and facilitate the in-silico design of synthetic AMPs. Results: Here we studied 14 AMP families and sub-families. We selected a specific description of AMP amino acid sequence and identified compositional and physicochemical properties of amino acids that accurately distinguish each AMP family from all other AMPs with an average sensitivity, specificity and precision of 92.88%, 99.86% and 95.96%, respectively. Many of our identified discriminative properties have been shown to be compositional or functional characteristics of the corresponding AMP family in literature. We suggest that these properties could serve as guides for in-silico methods in design of novel synthetic AMPs. The methodology we developed is generic and has a potential to be applied for characterization of any protein family.

  14. Functions of antimicrobial peptides in host defense and immunity.

    Science.gov (United States)

    Beisswenger, Christoph; Bals, Robert

    2005-06-01

    Antimicrobial peptides (AMPs) are effector molecules of the innate immune system. AMPs have a broad antimicrobial spectrum and lyse microbial cells by interaction with biomembranes. Besides their direct antimicrobial function, they have multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cytokine release, cell proliferation, angiogenesis, wound healing, chemotaxis, immune induction, and protease-antiprotease balance. Furthermore, AMPs qualify as prototypes of innovative drugs that may be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation. This review summarizes the current knowledge about the basic and applied biology of antimicrobial peptides and discusses features of AMPs in host defense and inflammation.

  15. From antimicrobial to anticancer peptides. A review.

    Directory of Open Access Journals (Sweden)

    Diana eGaspar

    2013-10-01

    Full Text Available Antimicrobial peptides (AMPs are part of the innate immune defense mechanism of many organisms. Although AMPs have been essentially studied and developed as potential alternatives for fighting infectious diseases, their use as anticancer peptides (ACPs in cancer therapy either alone or in combination with other conventional drugs has been regarded as a therapeutic strategy to explore. As human cancer remains a cause of high morbidity and mortality worldwide, an urgent need of new, selective and more efficient drugs is evident. Even though ACPs are expected to be selective towards tumor cells without impairing the normal body physiological functions, the development of a selective ACP has been a challenge. It is not yet possible to predict antitumor activity based on ACPs structures. ACPs are unique molecules when compared to the actual chemotherapeutic arsenal available for cancer treatment and display a variety of modes of action which in some types of cancer seem to co-exist. Regardless the debate surrounding the definition of structure-activity relationships for ACPs, great effort has been invested in ACP design and the challenge of improving effective killing of tumor cells remains. As detailed studies on ACPs mechanisms of action are crucial for optimizing drug development, in this review we provide an overview of the literature concerning peptides’ structure, modes of action, selectivity and efficacy and also summarize some of the many ACPs studied and/or developed for targeting different solid and hematologic malignancies with special emphasis on the first group. Strategies described for drug development and for increasing peptide selectivity towards specific cells while reducing toxicity are also discussed.

  16. Decreased outer membrane permeability protects mycobacteria from killing by ubiquitin-derived peptides

    OpenAIRE

    Purdy, Georgiana E.; Niederweis, Michael; Russell, David G.

    2009-01-01

    Ubiquitin-derived peptides are bactericidal in vitro and contribute to the mycobactericidal activity of the lysosome. To further define interactions of ubiquitin-derived peptides with mycobacteria, we screened for mutants with increased resistance to the bactericidal activity of the synthetic ubiquitin-derived peptide Ub2. The four Ub2-resistant M. smegmatis mutants were also resistant to the bactericidal action of other antimicrobial peptides and macrophages. Two mutants were in the mspA gen...

  17. The Role Of Milk Peptide As Antimicrobial Agent In Supporting Health Status

    Directory of Open Access Journals (Sweden)

    Eni Kusumaningtyas

    2013-06-01

    Full Text Available Antimicrobial peptide is commonly present in all species as a component of their innate immune defense against infection. Antimicrobial peptides derived from milk such as isracidin, casocidin, casecidin and other fragments with variety of amino acid sequence are released upon enzymatic hydrolysis from milk protein К-casein, α-casein, β-casein, α-lactalbumin and β- lactoglobulin. These peptides were produced by the activity of digestive or microbial protease such as trypsin, pepsin, chymosin or alcalase. The mode of action of these peptides is by interaction of their positive with negative charge of target cell membrane leading to disruption of membrane associated with physiological event such as cell division or translocation of peptide across the membrane to interact with cytoplasmic target. Modification of charged or nonpolar aliphatic residues within peptides can enhance or reduce the activities of the peptides against a number of microbial strains and it seems to be strain dependent. Several peptides act not only as an antimicrobial but also as an angiotensin-converting enzyme inhibitor, antioxidant, immunomodulator, antiinflamation, food and feed preservative. Although the commercial production of these peptides is still limited due to lack of suitable large-scale technologies, fast development of some methods for peptide production will hopefully increase the possibility for mass production.

  18. Role of Antimicrobial Peptides in Inflammatory Bowel Disease

    Directory of Open Access Journals (Sweden)

    Stefan Vordenbäumen

    2011-11-01

    Full Text Available Inflammatory bowel diseases (IBD are characterized by a chronic relapsing inflammation of the gastrointestinal mucosa. The etiology and pathogenesis of these disorders such as Crohn’s disease and ulcerative colitis are incompletely understood. Recently, antimicrobial peptides, which are expressed by leukocytes and epithelia, have been implicated in the pathogenesis of IBD. Antimicrobial peptides are pivotal for intestinal defense, shaping the composition of the luminal flora and contributing thereby to the maintenance of intestinal homeostasis. Apart from their antimicrobial activity affecting commensal bacteria, immunomodulatory properties of antimicrobial peptides have been identified, which link innate and adaptive immune response. There is increasing evidence that alterations in mucosal levels of these peptides contribute to IBD pathogenensis.

  19. ANTIMICROBIAL PEPTIDES: AN EFFECTIVE ALTERNATIVE FOR ANTIBIOTIC THERAPY

    Directory of Open Access Journals (Sweden)

    KK PULICHERLA

    2013-01-01

    Full Text Available Extensive use of classical antibiotics has led to the growing emergence of many resistant strains of pathogenic bacteria. Evidence has suggested that cationic antimicrobial peptides (AMP’s are of greatest potential to represent a new class of antibiotics. These peptides have a good scope in current antibiotic research. During the past two decades several AMPs have been isolated from a wide variety of animals (both vertebrates and invertebrates, and plants as well as from bacteria and fungi. These are relatively small (<10kDa, cationic and amphipathic peptides of variable length, sequence and structure. These peptides exhibit broad-spectrum activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, protozoa, yeast, fungi and viruses. Most of these peptides are believed to act by disrupting the plasma membrane leading to the lysis of the cell. Antimicrobial peptides encompass a wide variety of structural motifs such as α -helical peptides, β -sheet peptides, looped peptides and extended peptides. Preparations enriched by a specific protein are rarely easily obtained from natural host cells. Hence, recombinant protein production is frequently the sole applicable procedure. Several fusion strategies have been developed for the expression and purification of small antimicrobial peptides (AMPs in recombinant bacterial expression systems which were produced by cloning. This article aims to review in brief the sources of antimicrobial peptides, diversity in structural features, mode of action, production strategies and insight into the current data on their antimicrobial activity followed by a brief comment on the peptides that have entered clinical trials.

  20. Antimicrobial properties of analgesic kyotorphin peptides unraveled through atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Marta M.B.; Franquelim, Henri G.; Torcato, Ines M. [Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa (Portugal); Ramu, Vasanthakumar G.; Heras, Montserrat; Bardaji, Eduard R. [Laboratori d' Innovacio en Processos i Productes de Sintesi Organica (LIPPSO), Departament de Quimica, Universitat de Girona, Campus Montilivi, 17071 Girona (Spain); Castanho, Miguel A.R.B., E-mail: macastanho@fm.ul.pt [Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa (Portugal)

    2012-04-13

    Highlights: Black-Right-Pointing-Pointer New kyotorphin derivatives have antimicrobial properties against S. aureus. Black-Right-Pointing-Pointer Atomic force microscopy show membrane disturbing effects of KTP-NH{sub 2} and IbKTP-NH{sub 2}. Black-Right-Pointing-Pointer None of the KTP derivatives are hemolytic. Black-Right-Pointing-Pointer The minimal peptidic sequence with antimicrobial activity is Tyr-Arg, if amidated. -- Abstract: Antimicrobial peptides (AMPs) are promising candidates as alternatives to conventional antibiotics for the treatment of resistant pathogens. In the last decades, new AMPs have been found from the cleavage of intact proteins with no antibacterial activity themselves. Bovine hemoglobin hydrolysis, for instance, results in AMPs and the minimal antimicrobial peptide sequence was defined as Tyr-Arg plus a positively charged amino acid residue. The Tyr-Arg dipeptide alone, known as kyotorphin (KTP), is an endogenous analgesic neuropeptide but has no antimicrobial activity itself. In previous studies new KTP derivatives combining C-terminal amidation and Ibuprofen (Ib) - KTP-NH{sub 2}, IbKTP, IbKTP-NH{sub 2} - were designed in order to improve KTP brain targeting. Those modifications succeeded in enhancing peptide-cell membrane affinity towards fluid anionic lipids and higher analgesic activity after systemic injection resulted therefrom. Here, we investigated if this affinity for anionic lipid membranes also translates into antimicrobial activity because bacteria have anionic membranes. Atomic force microscopy revealed that KTP derivatives perturbed Staphylococcus aureus membrane structure by inducing membrane blebbing, disruption and lysis. In addition, these peptides bind to red blood cells but are non-hemolytic. From the KTP derivatives tested, amidated KTP proves to be the most active antibacterial agent. The combination of analgesia and antibacterial activities with absence of toxicity is highly appealing from the clinical point of view

  1. De-novo design of antimicrobial peptides for plant protection.

    Directory of Open Access Journals (Sweden)

    Benjamin Zeitler

    Full Text Available This work describes the de-novo design of peptides that inhibit a broad range of plant pathogens. Four structurally different groups of peptides were developed that differ in size and position of their charged and hydrophobic clusters and were assayed for their ability to inhibit bacterial growth and fungal spore germination. Several peptides are highly active at concentrations between 0,1 and 1 µg/ml against plant pathogenic bacteria, such as Pseudomonas syringae, Pectobacterium carotovorum, and Xanthomonas vesicatoria. Importantly, no hemolytic activity could be detected for these peptides at concentrations up to 200 µg/ml. Moreover, the peptides are also active after spraying on the plant surface demonstrating a possible way of application. In sum, our designed peptides represent new antimicrobial agents and with the increasing demand for antimicrobial compounds for production of "healthy" food, these peptides might serve as templates for novel antibacterial and antifungal agents.

  2. Characterization and performance of short cationic antimicrobial peptide isomers.

    Science.gov (United States)

    Juba, Melanie; Porter, Devin; Dean, Scott; Gillmor, Susan; Bishop, Barney

    2013-07-01

    Cationic antimicrobial peptides (CAMPs) represent an ancient defense mechanism against invading bacteria, with peptides such as the cathelicidins being essential elements of vertebrate innate immunity. CAMPs are typically associated with broad-spectrum antimicrobial potency and limited bacterial resistance. The cathelicidin identified from the elapid snake Naja atra (NA-CATH) contains a semi-conserved repeated 11-residue motif (ATRA motif) with a sequence pattern consistent with formation of an amphipathic helical conformation. Short peptide amides (ATRA-1, -1A, -1P, and -2) generated based on the pair of ATRA motifs in NA-CATH exhibited varied antimicrobial potencies. The small size of the ATRA peptides, coupled with their varied antimicrobial performances, make them interesting models to study the impact various physico-chemical properties have on antimicrobial performance in helical CAMPs. Accordingly, the D- and L-enantiomers of the peptide ATRA-1A, which in earlier studies had shown both good antimicrobial performance and strong helical character, were investigated in order to assess the impact peptide stereochemistry has on antimicrobial performance and interaction with chiral membranes. The ATRA-1A isomers exhibit varied potencies against four bacterial strains, and their conformational properties in the presence of mixed zwitterionic/anionic liposomes are influenced by anionic lipid content. These studies reveal subtle differences in the properties of the peptide isomers. Differences are also seen in the abilities of the ATRA-1A isomers to induce liposome fusion/aggregation, bilayer rearrangement and lysing through turbidity studies and fluorescence microscopy. The similarities and differences in the properties of the ATRA-1A isomers could aid in efforts to develop D-peptide-based therapeutics using high-performing L-peptides as templates.

  3. The role of antimicrobial peptides in cardiovascular physiology and disease.

    Science.gov (United States)

    Li, Yifeng

    2009-12-18

    Antimicrobial peptides are natural peptide antibiotics, existing ubiquitously in both plant and animal kingdoms. They exhibit broad-spectrum antimicrobial activity and play an important role in host defense against invading microbes. Recently, these peptides have been shown to possess activities unrelated to direct microbial killing and be involved in the complex network of immune responses and inflammation. Thus, their role has now broadened beyond that of endogenous antibiotics. Because of their wide involvement in inflammatory response and the emerging role of inflammation in atherosclerosis, antimicrobial peptides have been proposed to represent an important link between inflammation and the pathogenesis of atherosclerotic cardiovascular diseases. This review highlights recent findings that support a role of these peptides in cardiovascular physiology and disease.

  4. Biofilm induced tolerance towards antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Anders Folkesson

    Full Text Available Increased tolerance to antimicrobial agents is thought to be an important feature of microbes growing in biofilms. We address the question of how biofilm organization affects antibiotic susceptibility. We established Escherichia coli biofilms with differential structural organization due to the presence of IncF plasmids expressing altered forms of the transfer pili in two different biofilm model systems. The mature biofilms were subsequently treated with two antibiotics with different molecular targets, the peptide antibiotic colistin and the fluoroquinolone ciprofloxacin. The dynamics of microbial killing were monitored by viable count determination, and confocal laser microscopy. Strains forming structurally organized biofilms show an increased bacterial survival when challenged with colistin, compared to strains forming unstructured biofilms. The increased survival is due to genetically regulated tolerant subpopulation formation and not caused by a general biofilm property. No significant difference in survival was detected when the strains were challenged with ciprofloxacin. Our data show that biofilm formation confers increased colistin tolerance to cells within the biofilm structure, but the protection is conditional being dependent on the structural organization of the biofilm, and the induction of specific tolerance mechanisms.

  5. Prediction of Antibacterial Activity from Physicochemical Properties of Antimicrobial Peptides

    NARCIS (Netherlands)

    de Sousa Pereira Simoes de Melo, Manuel; Ferre, Rafael; Feliu, Lidia; Bardaji, Eduard; Planas, Marta; Castanho, Miguel A. R. B.

    2011-01-01

    Consensus is gathering that antimicrobial peptides that exert their antibacterial action at the membrane level must reach a local concentration threshold to become active. Studies of peptide interaction with model membranes do identify such disruptive thresholds but demonstrations of the possible co

  6. Cell-penetrating antimicrobial peptides - prospectives for targeting intracellular infections

    DEFF Research Database (Denmark)

    Bahnsen, Jesper S; Franzyk, Henrik; Sayers, Edward J;

    2015-01-01

    La WT cells and analyzed by flow cytometry and confocal microscopy. Furthermore, the effects of the peptides on eukaryotic cell viability as well as their antimicrobial effect were tested. In addition, the disrupting ability of the peptides in the presence of bilayer membranes of different composition...

  7. DRAMP: a comprehensive data repository of antimicrobial peptides.

    Science.gov (United States)

    Fan, Linlin; Sun, Jian; Zhou, Meifeng; Zhou, Jie; Lao, Xingzhen; Zheng, Heng; Xu, Hanmei

    2016-01-01

    The growing problem of antibiotic-resistant microorganisms results in an urgent need for substitutes to conventional antibiotics with novel modes of action and effective activities. Antimicrobial peptides (AMPs), produced by a wide variety of living organisms acting as a defense mechanism against invading pathogenic microbes, are considered to be such promising alternatives. AMPs display a broad spectrum of antimicrobial activity and a low propensity for developing resistance. Therefore, a thorough understanding of AMPs is essential to exploit them as antimicrobial drugs. Considering this, we developed a comprehensive user-friendly data repository of antimicrobial peptides (DRAMP), which holds 17349 antimicrobial sequences, including 4571 general AMPs, 12704 patented sequences and 74 peptides in drug development. Entries in the database have detailed annotations, especially detailed antimicrobial activity data (shown as target organism with MIC value) and structure information. Annotations also include accession numbers crosslinking to Pubmed, Swiss-prot and Protein Data Bank (PDB). The website of the database comes with easy-to-operate browsing as well as searching with sorting and filtering functionalities. Several useful sequence analysis tools are provided, including similarity search, sequence alignment and conserved domain search (CD-Search). DRAMP should be a useful resource for the development of novel antimicrobial peptide drugs. PMID:27075512

  8. Evolution of Antimicrobial Peptides to Self-Assembled Peptides for Biomaterial Applications

    Directory of Open Access Journals (Sweden)

    Alice P. McCloskey

    2014-10-01

    Full Text Available Biomaterial-related infections are a persistent burden on patient health, recovery, mortality and healthcare budgets. Self-assembled antimicrobial peptides have evolved from the area of antimicrobial peptides. Peptides serve as important weapons in nature, and increasingly medicine, for combating microbial infection and biofilms. Self-assembled peptides harness a “bottom-up” approach, whereby the primary peptide sequence may be modified with natural and unnatural amino acids to produce an inherently antimicrobial hydrogel. Gelation may be tailored to occur in the presence of physiological and infective indicators (e.g. pH, enzymes and therefore allow local, targeted antimicrobial therapy at the site of infection. Peptides demonstrate inherent biocompatibility, antimicrobial activity, biodegradability and numerous functional groups. They are therefore prime candidates for the production of polymeric molecules that have the potential to be conjugated to biomaterials with precision. Non-native chemistries and functional groups are easily incorporated into the peptide backbone allowing peptide hydrogels to be tailored to specific functional requirements. This article reviews an area of increasing interest, namely self-assembled peptides and their potential therapeutic applications as innovative hydrogels and biomaterials in the prevention of biofilm-related infection.

  9. Cathelicidin peptides as candidates for a novel class of antimicrobials.

    Science.gov (United States)

    Zanetti, Margherita; Gennaro, Renato; Skerlavaj, Barbara; Tomasinsig, Linda; Circo, Raffaella

    2002-01-01

    Cathelicidin peptides are a numerous group of mammalian cationic antimicrobial peptides. Despite a common evolutionary origin of their genes, peptides display a remarkable variety of sizes, sequences and structures. Their spectra of antimicrobial activity are varied and cover a range of organisms that includes bacteria, fungi and enveloped viruses. In addition, they bind to and neutralize the effects of endotoxin. These features make this family of peptides good candidates in view of a therapeutic use. The most promising ones are currently under evaluation as leads for the development of novel anti-infectives, and synthetic variants are in an advanced stage of development for specific clinical applications. This review focuses on recent studies on the structure and in vitro and in vivo biological activities of these peptides. PMID:11945171

  10. Cholic acid derivatives: novel antimicrobials.

    Science.gov (United States)

    Savage, P B; Li, C

    2000-02-01

    Mimics of squalamine and polymyxin B (PMB) have been prepared from cholic acid in hope of finding new antimicrobial agents. The squalamine mimics include the polyamine and sulphate functionalities found in the parent antibiotic, however, the positions relative to the steroid nucleus have been exchanged. The PMB mimics include the conservation of functionality among the polymyxin family of antibiotics, the primary amine groups and a hydrophobic chain. Although the squalamine and PMB mimics are morphologically dissimilar, they display similar activities. Both are simple to prepare and demonstrate broad spectrum antimicrobial activity against Gram-negative and Gram-positive organisms. Specific examples may be inactive alone, yet effectively permeabilise the outer membranes of Gram-negative bacteria rendering them sensitive to hydrophobic antibiotics. Problems associated with some of the squalamine and PMB mimics stem from their haemolytic activity and interactions with serum proteins, however, examples exist without these side effects which can sensitise Gram-negative bacteria to hydrophobic antibiotics. PMID:11060676

  11. Antimicrobial Activity of Lactoferrin-Related Peptides and Applications in Human and Veterinary Medicine.

    Science.gov (United States)

    Bruni, Natascia; Capucchio, Maria Teresa; Biasibetti, Elena; Pessione, Enrica; Cirrincione, Simona; Giraudo, Leonardo; Corona, Antonio; Dosio, Franco

    2016-01-01

    Antimicrobial peptides (AMPs) represent a vast array of molecules produced by virtually all living organisms as natural barriers against infection. Among AMP sources, an interesting class regards the food-derived bioactive agents. The whey protein lactoferrin (Lf) is an iron-binding glycoprotein that plays a significant role in the innate immune system, and is considered as an important host defense molecule. In search for novel antimicrobial agents, Lf offers a new source with potential pharmaceutical applications. The Lf-derived peptides Lf(1-11), lactoferricin (Lfcin) and lactoferrampin exhibit interesting and more potent antimicrobial actions than intact protein. Particularly, Lfcin has demonstrated strong antibacterial, anti-fungal and antiparasitic activity with promising applications both in human and veterinary diseases (from ocular infections to osteo-articular, gastrointestinal and dermatological diseases). PMID:27294909

  12. Mechanism of bacterial membrane poration by Antimicrobial Peptides

    Science.gov (United States)

    Arora, Ankita; Mishra, Abhijit

    2015-03-01

    Bacterial resistance to conventional antibiotics is a major health concern. Antimicrobial peptides (AMPs), an important component of mammalian immune system, are thought to utilize non-specific interactions to target common features on the outer membranes of pathogens; hence development of resistance to such AMPs may be less pronounced. Most AMPs are amphiphilic and cationic in nature. Most AMPs form pores in the bacterial membranes causing them to lyse, however, the exact mechanism is unknown. Here, we study the AMP CHRG01 (KSSTRGRKSSRRKK), derived from human β defensin 3 (hBD3) with all Cysteine residues substituted with Serine. Circular Dichorism studies indicate that CHRG01 shows helicity and there is change in helicity as it interacts with the lipid membrane. The AMP was effective against different species of bacteria. Leakage of cellular components from bacterial cells observed by SEM and AFM indicates AMP action by pore formation. Confocal microscopy studies on giant vesicles incubated with AMP confirm poration. The effect of this AMP on model bacterial membranes is characterized using Small Angle X-ray scattering and Fluorescence spectroscopy to elucidate the mechanism behind antimicrobial activity.

  13. Multifunctional host defense peptides: antimicrobial peptides, the small yet big players in innate and adaptive immunity.

    Science.gov (United States)

    Auvynet, Constance; Rosenstein, Yvonne

    2009-11-01

    The term 'antimicrobial peptides' refers to a large number of peptides first characterized on the basis of their antibiotic and antifungal activities. In addition to their role as endogenous antibiotics, antimicrobial peptides, also called host defense peptides, participate in multiple aspects of immunity (inflammation, wound repair, and regulation of the adaptive immune system) as well as in maintaining homeostasis. The possibility of utilizing these multifunctional molecules to effectively combat the ever-growing group of antibiotic-resistant pathogens has intensified research aimed at improving their antibiotic activity and therapeutic potential, without the burden of an exacerbated inflammatory response, but conserving their immunomodulatory potential. In this minireview, we focus on the contribution of small cationic antimicrobial peptides - particularly human cathelicidins and defensins - to the immune response and disease, highlighting recent advances in our understanding of the roles of these multifunctional molecules.

  14. Diversity, evolution and medical applications of insect antimicrobial peptides

    OpenAIRE

    Mylonakis, Eleftherios; Podsiadlowski, Lars; Muhammed, Maged; Vilcinskas, Andreas

    2016-01-01

    Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolutio...

  15. Collectins and Cationic Antimicrobial Peptides of the Respiratory Epithelia

    OpenAIRE

    Grubor, B.; Meyerholz, D. K.; Ackermann, M R

    2006-01-01

    The respiratory epithelium is a primary site for the deposition of microorganisms that are acquired during inspiration. The innate immune system of the respiratory tract eliminates many of these potentially harmful agents preventing their colonization. Collectins and cationic antimicrobial peptides are antimicrobial components of the pulmonary innate immune system produced by respiratory epithelia, which have integral roles in host defense and inflammation in the lung. Synthesis and secretion...

  16. [Insect antimicrobial peptides: structures, properties and gene regulation].

    Science.gov (United States)

    Wang, Yi-Peng; Lai, Ren

    2010-02-01

    Insect antimicrobial peptides (AMPs) are an important group of insect innate immunity effectors. Insect AMPs are cationic and contain less than 100 amino acid residues. According to structure, insect AMPs can be divided into a limited number of families. The diverse antimicrobial spectrum of insect AMPs may indicate different modes of action. Research on the model organism Drosophila indicate that insect AMPs gene regulation involves multiple signaling pathways and a large number of signaling molecules.

  17. Caseins from bovine colostrum and milk strongly bind piscidin-1, an antimicrobial peptide from fish.

    Science.gov (United States)

    Kütt, Mary-Liis; Stagsted, Jan

    2014-09-01

    A model system of bovine colostrum and piscidin, a fish-derived antimicrobial peptide, was developed to study potential interactions of antimicrobial peptides in colostrum. We did not detect any antimicrobial activity of colostrum using the radial plate diffusion assay; in fact colostrum completely abrogated activity of added piscidin. This could not be explained by degradation of piscidin by colostrum, which was less than ten percent. We found that colostrum even protected piscidin against degradation by added proteases. We further observed that colostrum and milk rapidly quenched the fluorescence of fluorescein-piscidin but not that of fluorescein. This effect was not seen with BSA and the specific quenching of fluorescein-piscidin by colostrum was saturably inhibited with unlabeled piscidin. Size exclusion chromatography indicated that fluorescein-piscidin bound to casein micelles with no apparent binding to IgG or whey proteins. Further, addition of pure caseins was able to quench fluorescence of fluorescein-piscidin and to inhibit the antimicrobial activity of piscidin. The interaction between caseins and piscidin could be dissociated by guanidine hydrochloride and recovered piscidin had antimicrobial activity against bacteria. Based on our results we propose that caseins could be carriers for antimicrobial peptides in colostrum and milk. PMID:25036607

  18. NMR and computational data of two novel antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    Lucia Falcigno

    2016-09-01

    Full Text Available Here we report details on the design and conformational analysis of two novel peptides showing antimicrobial properties, as reported in the research article, “New antimicrobial peptides against foodborne pathogens: from in silico design to experimental evidence” G. Palmieri, M. Balestrieri, Y.T.R. Proroga, L. Falcigno, A. Facchiano, A. Riccio, F. Capuano, R. Marrone, G. Campanile, A. Anastasio (2016 [1]. NMR data, such as chemical shifts in two different solvents as well as aCH protons deviations from random coil values and NOE patterns, are shown together with the statistics of structural calculations. Strategy and particulars of molecular design are presented.

  19. Single molecule resolution of the antimicrobial action of quantum dot-labeled sushi peptide on live bacteria

    Directory of Open Access Journals (Sweden)

    Chen Jianzhu

    2009-05-01

    Full Text Available Abstract Background Antimicrobial peptides are found in all kingdoms of life. During the evolution of multicellular organisms, antimicrobial peptides were established as key elements of innate immunity. Most antimicrobial peptides are thought to work by disrupting the integrity of cell membranes, causing pathogen death. As antimicrobial peptides target the membrane structure, pathogens can only acquire resistance by a fundamental change in membrane composition. Hence, the evolution of pathogen resistance has been a slow process. Therefore antimicrobial peptides are valuable alternatives to classical antibiotics against which multiple drug-resistant bacteria have emerged. For potential therapeutic applications as antibiotics a thorough knowledge of their mechanism of action is essential. Despite the increasingly comprehensive understanding of the biochemical properties of these peptides, the actual mechanism by which antimicrobial peptides lyse microbes is controversial. Results Here we investigate how Sushi 1, an antimicrobial peptide derived from the horseshoe crab (Carcinoscorpius rotundicauda, induces lysis of Gram-negative bacteria. To follow the entire process of antimicrobial action, we performed a variety of experiments including transmission electron microscopy and fluorescence correlation spectroscopy as well as single molecule tracking of quantum dot-labeled antimicrobial peptides on live bacteria. Since in vitro measurements do not necessarily correlate with the in vivo action of a peptide we developed a novel fluorescent live bacteria lysis assay. Using fully functional nanoparticle-labeled Sushi 1, we observed the process of antimicrobial action at the single-molecule level. Conclusion Recently the hypothesis that many antimicrobial peptides act on internal targets to kill the bacterium has been discussed. Here, we demonstrate that the target sites of Sushi 1 are outer and inner membranes and are not cytosolic. Further, our findings

  20. Antimicrobial Peptide-Lipid Binding Interactions and Binding Selectivity

    OpenAIRE

    Lad, Mitaben D.; Birembaut, Fabrice; Clifton, Luke A.; Frazier, Richard A.; Webster, John R. P.; Green, Rebecca J.

    2007-01-01

    Surface pressure measurements, external reflection-Fourier transform infrared spectroscopy, and neutron reflectivity have been used to investigate the lipid-binding behavior of three antimicrobial peptides: melittin, magainin II, and cecropin P1. As expected, all three cationic peptides were shown to interact more strongly with the anionic lipid, 1,2 dihexadecanoyl-sn-glycerol-3-(phosphor-rac-(1-glycerol)) (DPPG), compared to the zwitterionic lipid, 1,2 dihexadecanoyl-sn-glycerol-3-phosphocho...

  1. Antimicrobial peptides: a new class of antimalarial drugs?

    Directory of Open Access Journals (Sweden)

    Nuno eVale

    2014-12-01

    Full Text Available A range of antimicrobial peptides (AMP exhibit activity on malaria parasites, Plasmodium spp, in their blood or mosquito stages, or both. These peptides include a diverse array of both natural and synthetic molecules varying greatly in size, charge, hydrophobicity and secondary structure features. Along with an overview of relevant literature reports regarding AMP that display antiplasmodial activity, this review makes a few considerations about those molecules as a potential new class of antimalarial drugs.

  2. Mechanism of action of cyclic antimicrobial peptides

    OpenAIRE

    Díaz i Cirac, Anna

    2011-01-01

    This PhD thesis is the result of the combination of experimental and computational techniques with the aim of understanding the mechanism of action of de novo cyclic decapeptides with high antimicrobial activity. By experimental techniques the influence of the replacement of the phenylalanine for tryptophan residue in their antimicrobial activity was tested and the stability in human serum was also analyzed, in order to evaluate their potential therapeutic application as antitumor agents. ...

  3. Alternatives to antibiotics: bacteriocins, antimicrobial peptides and bacteriophages.

    Science.gov (United States)

    Joerger, R D

    2003-04-01

    Bacteriocins, antimicrobial peptides, and bacteriophage have attracted attention as potential substitutes for, or as additions to, currently used antimicrobial compounds. This publication will review research on the potential application of these alternative antimicrobial agents to poultry production and processing. Bacteriocins are proteinaceous compounds of bacterial origin that are lethal to bacteria other than the producing strain. It is assumed that some of the bacteria in the intestinal tract produce bacteriocins as a means to achieve a competitive advantage, and bacteriocin-producing bacteria might be a desirable part of competitive exclusion preparations. Purified or partially purified bacteriocins could be used as preservatives or for the reduction or elimination of certain pathogens. Currently only nisin, produced by certain strains of Lactococcus lactis subsp. lactis, has regulatory approval for use in certain foods, and its use for poultry products has been studied extensively. Exploration of the application of antimicrobial peptides from sources other than bacteria to poultry has not yet commenced to a significant extent. Evidence for the ability of chickens to produce such antimicrobial peptides has been provided, and it is likely that these peptides play an important role in the defense against various pathogens. Bacteriophages have received renewed attention as possible agents against infecting bacteria. Evidence from several trials indicates that phage therapy can be effective under certain circumstances. Numerous obstacles for the use of phage as antimicrobials for poultry or poultry products remain. Chiefly among them are the narrow host range of many phages, the issue of phage resistance, and the possibility of phage-mediated transfer of genetic material to bacterial hosts. Regulatory issues and the high cost of producing such alternative antimicrobial agents are also factors that might prevent application of these agents in the near future

  4. Membrane damage as first and DNA as the secondary target for anti-candidal activity of antimicrobial peptide P7 derived from cell-penetrating peptide ppTG20 against Candida albicans.

    Science.gov (United States)

    Li, Lirong; Song, Fengxia; Sun, Jin; Tian, Xu; Xia, Shufang; Le, Guowei

    2016-06-01

    P7, a peptide analogue derived from cell-penetrating peptide ppTG20, possesses antibacterial and antitumor activities without significant hemolytic activity. In this study, we investigated the antifungal effect of P7 and its anti-Candida acting mode in Candida albicans. P7 displayed antifungal activity against the reference C. albicans (MIC = 4 μM), Aspergilla niger (MIC = 32 μM), Aspergillus flavus (MIC = 8 μM), and Trichopyton rubrum (MIC = 16 μM). The effect of P7 on the C. albicans cell membrane was examined by investigating the calcein leakage from fungal membrane models made of egg yolk l-phosphatidylcholine/ergosterol (10 : 1, w/w) liposomes. P7 showed potent leakage effects against fungal liposomes similar to Melittin-treated cells. C. albicans protoplast regeneration assay demonstrated that P7 interacted with the C. albicans plasma membrane. Flow cytometry of the plasma membrane potential and integrity of C. albicans showed that P7 caused 60.9 ± 1.8% depolarization of the membrane potential of intact C. albicans cells and caused 58.1 ± 3.2% C. albicans cell membrane damage. Confocal laser scanning microscopy demonstrated that part of FITC-P7 accumulated in the cytoplasm. DNA retardation analysis was also performed, which showed that P7 interacted with C. albicans genomic DNA after penetrating the cell membrane, completely inhibiting the migration of genomic DNA above the weight ratio (peptide : DNA) of 6. Our results indicated that the plasma membrane was the primary target, and DNA was the secondary intracellular target of the mode of action of P7 against C. albicans. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. PMID:27197902

  5. Toroidal pores formed by antimicrobial peptides show significant disorder

    NARCIS (Netherlands)

    Sengupta, Durba; Leontiadou, Hari; Mark, Alan E.; Marrink, Siewert-Jan

    2008-01-01

    A large variety of antimicrobial peptides have been shown to act, at least in vitro, by potation of the lipid membrane. The nanometre size of these pores, however, complicates their structural characterization by experimental techniques. Here we use molecular dynamics simulations, to study the inter

  6. Engineering Dehydrated Amino Acid Residues in the Antimicrobial Peptide Nisin

    NARCIS (Netherlands)

    Kuipers, Oscar P.; Rollema, Harry S.; Yap, Wyanda M.G.J.; Boot, Hein J.; Siezen, Roland J.; Vos, Willem M. de

    1992-01-01

    The small antimicrobial peptide nisin, produced by Lactococcus lactis, contains the uncommon amino acid residues dehydroalanine and dehydrobutyrine and five thio ether bridges. Since these structures are posttranslationally formed from Ser, Thr, and Cys residues, it is feasible to study their role i

  7. Selected antimicrobial peptides inhibit in vitro growth of Campylobacter spp.

    Science.gov (United States)

    Novel alternatives to traditional antibiotics are urgently needed for food-animal production. A goal of our laboratory is to develop and evaluate antimicrobial peptides (AMP) to control and reduce foodborne pathogens in poultry. AMP have been found in most every class of living organism where they h...

  8. Amplifying renal immunity: the role of antimicrobial peptides in pyelonephritis.

    Science.gov (United States)

    Becknell, Brian; Schwaderer, Andrew; Hains, David S; Spencer, John David

    2015-11-01

    Urinary tract infections (UTIs), including pyelonephritis, are among the most common and serious infections encountered in nephrology practice. UTI risk is increased in selected patient populations with renal and urinary tract disorders. As the prevalence of antibiotic-resistant uropathogens increases, novel and alternative treatment options will be needed to reduce UTI-associated morbidity. Discoveries over the past decade demonstrate a fundamental role for the innate immune system in protecting the urothelium from bacterial challenge. Antimicrobial peptides, an integral component of this urothelial innate immune system, demonstrate potent bactericidal activity toward uropathogens and might represent a novel class of UTI therapeutics. The urothelium of the bladder and the renal epithelium secrete antimicrobial peptides into the urinary stream. In the kidney, intercalated cells--a cell-type involved in acid-base homeostasis--have been shown to be an important source of antimicrobial peptides. Intercalated cells have therefore become the focus of new investigations to explore their function during pyelonephritis and their role in maintaining urinary tract sterility. This Review provides an overview of UTI pathogenesis in the upper and lower urinary tract. We describe the role of intercalated cells and the innate immune response in preventing UTI, specifically highlighting the role of antimicrobial peptides in maintaining urinary tract sterility.

  9. Chicken antimicrobial peptides: biological functions and possible applications

    NARCIS (Netherlands)

    Dijk, Albert van

    2007-01-01

    Farm animals often suffer from diseases of the gastro-intestinal tract. Modulation of natural defence mechanisms by dietary additives may be one way to improve intestinal health and food safety. In mammals, antimicrobial peptides (AMPs) play an important role in the host defence of skin and mucosal

  10. Burkholderia cenocepacia zinc metalloproteases influence resistance to antimicrobial peptides.

    Science.gov (United States)

    Kooi, Cora; Sokol, Pamela A

    2009-09-01

    Burkholderia cenocepacia secretes two zinc-dependent metalloproteases, designated ZmpA and ZmpB. Previously, ZmpA and ZmpB have been shown to cleave several proteins important in host defence. In this study, the ability of ZmpA and ZmpB to digest and inactivate antimicrobial peptides involved in innate immunity was examined. ZmpB but not ZmpA cleaved beta-defensin-1. ZmpA but not ZmpB cleaved the cathelicidin LL-37. Both enzymes cleaved elafin and secretory leukocyte inhibitor, which are antimicrobial peptides as well as neutrophil elastase inhibitors. Both ZmpA and ZmpB cleaved protamine, a fish antimicrobial peptide, and a zmpA zmpB mutant was more sensitive to protamine killing than the parental strain. ZmpA or ZmpB cleavage of elafin inactivated its anti-protease activity. The effect of ZmpA and ZmpB on the neutrophil proteases elastase and cathepsin G was also examined but neither enzyme was active against these host proteases. These studies suggest that ZmpA and ZmpB may influence the resistance of B. cenocepacia to host antimicrobial peptides as well as alter the host protease/anti-protease balance in chronic respiratory infections.

  11. Antimicrobial properties and membrane-active mechanism of a potential α-helical antimicrobial derived from cathelicidin PMAP-36.

    Directory of Open Access Journals (Sweden)

    Yinfeng Lv

    Full Text Available Antimicrobial peptides (AMPs, which present in the non-specific immune system of organism, are amongst the most promising candidates for the development of novel antimicrobials. The modification of naturally occurring AMPs based on their residue composition and distribution is a simple and effective strategy for optimization of known AMPs. In this study, a series of truncated and residue-substituted derivatives of antimicrobial peptide PMAP-36 were designed and synthesized. The 24-residue truncated peptide, GI24, displayed antimicrobial activity comparable to the mother peptide PMAP-36 with MICs ranging from 1 to 4 µM, which is lower than the MICs of bee venom melittin. Although GI24 displayed high antimicrobial activity, its hemolytic activity was much lower than melittin, suggesting that GI24 have optimal cell selectivity. In addition, the crucial site of GI24 was identified through single site-mutation. An amino acid with high hydrophobicity at position 23 played an important role in guaranteeing the high antimicrobial activity of GI24. Then, lipid vesicles and whole bacteria were employed to investigate the membrane-active mechanisms. Membrane-simulating experiments showed that GI24 interacted strongly with negatively charged phospholipids and weakly with zwitterionic phospholipids, which corresponded well with the data of its biological activities. Membrane permeabilization and flow cytometry provide the evidence that GI24 killed microbial cells by permeabilizing the cell membrane and damaging membrane integrity. GI24 resulted in greater cell morphological changes and visible pores on cell membrane as determined using scanning electron microscopy (SEM and transmission electron microscope (TEM. Taken together, the peptide GI24 may provide a promising antimicrobial agent for therapeutic applications against the frequently-encountered bacteria.

  12. Antimicrobial peptides: natural templates for synthetic membrane-active compounds.

    Science.gov (United States)

    Giuliani, A; Pirri, G; Bozzi, A; Di Giulio, A; Aschi, M; Rinaldi, A C

    2008-08-01

    The innate immunity of multicellular organisms relies in large part on the action of antimicrobial peptides (AMPs) to resist microbial invasion. Crafted by evolution into an extremely diversified array of sequences and folds, AMPs do share a common amphiphilic 3-D arrangement. This feature is directly linked with a common mechanism of action that predominantly (although not exclusively) develops upon interaction of peptides with cell membranes of target cells. This minireview reports on current understanding of the modes of interaction of AMPs with biological and model membranes, especially focusing on recent insights into the folding and oligomerization requirements of peptides to bind and insert into lipid membranes and exert their antibiotic effects. Given the potential of AMPs to be developed into a new class of anti-infective agents, emphasis is placed on how the information on peptide-membrane interactions could direct the design and selection of improved biomimetic synthetic peptides with antibiotic properties.

  13. Design and Engineering Strategies for Synthetic Antimicrobial Peptides

    Science.gov (United States)

    Tossi, Alessandro

    Thousands of antimicrobial peptides (AMPs) of prokaryotic, fungal, plant, or animal origin have been identified, and their potential as lead compounds for the design of novel therapeutic agents in the treatment of infection, for stimulating the immune system, or in countering septic shock has been widely recognized. Added to this is their possible use in prophylaxis of infectious diseases for animal or plant protection, for disinfection of surgical instruments or industrial surfaces, and for food preservation among other commercially important applications. Since the early eighties, AMPs have been subject to a vast number of studies aimed at understanding what determines their potency and spectrum of activities against bacterial or fungal pathogens, and at maximizing these while limiting cytotoxic activities toward host cells. Much research has also been directed toward understanding specific mechanisms of action underlying the antimicrobial activity and selectivity, to be able to redesign the peptides for optimal performance. A central theme in the mode of action of many AMPs is their dynamic interaction with biological membranes, which involves various properties of these peptides such as, among others, surface hydrophobicity and polarity, charge, structure, and induced conformational variations. These features are often intimately interconnected so that engineering peptides to independently adjust any one property in particular is not an easy task. However, solid-phase peptide synthesis allows the use of a large repertoire of nonproteinogenic amino acids that can be used in the rational design of peptides to finely tune structural and physicochemical properties and precisely probe structure-function relationships.

  14. Epithelial Antimicrobial Peptides: Guardian of the Oral Cavity

    Directory of Open Access Journals (Sweden)

    Mayank Hans

    2014-01-01

    Full Text Available Gingival epithelium provides first line of defence from the microorganisms present in dental plaque. It not only provides a mechanical barrier but also has an active immune function too. Gingival epithelial cells participate in innate immunity by producing a range of antimicrobial peptides to protect the host against oral pathogens. These epithelial antimicrobial peptides (EAPs include the β-defensin family, cathelicidin (LL-37, calprotectin, and adrenomedullin. While some are constitutively expressed in gingival epithelial cells, others are induced upon exposure to microbial insults. It is likely that these EAPs have a role in determining the initiation and progression of oral diseases. EAPs are broad spectrum antimicrobials with a different but overlapping range of activity. Apart from antimicrobial activity, they participate in several other crucial roles in host tissues. Some of these, for instance, β-defensins, are chemotactic to immune cells. Others, such as calprotectin are important for wound healing and cell proliferation. Adrenomedullin, a multifunctional peptide, has its biological action in a wide range of tissues. Not only is it a potent vasodilator but also it has several endocrine effects. Knowing in detail the various bioactions of these EAPs may provide us with useful information regarding their utility as therapeutic agents.

  15. The role of antimicrobial peptides in animal defenses

    Science.gov (United States)

    Hancock, Robert E. W.; Scott, Monisha G.

    2000-08-01

    It is becoming clear that the cationic antimicrobial peptides are an important component of the innate defenses of all species of life. Such peptides can be constitutively expressed or induced by bacteria or their products. The best peptides have good activities vs. a broad range of bacterial strains, including antibiotic-resistant isolates. They kill very rapidly, do not easily select resistant mutants, are synergistic with conventional antibiotics, other peptides, and lysozyme, and are able to kill bacteria in animal models. It is known that bacterial infections, especially when treated with antibiotics, can lead to the release of bacterial products such as lipopolysaccharide (LPS) and lipoteichoic acid, resulting in potentially lethal sepsis. In contrast to antibiotics, the peptides actually prevent cytokine induction by bacterial products in tissue culture and human blood, and they block the onset of sepsis in mouse models of endotoxemia. Consistent with this, transcriptional gene array experiments using a macrophage cell line demonstrated that a model peptide, CEMA, blocks the expression of many genes whose transcription was induced by LPS. The peptides do this in part by blocking LPS interaction with the serum protein LBP. In addition, CEMA itself has a direct effect on macrophage gene expression. Because cationic antimicrobial peptides are induced by LPS and are able to dampen the septic response of animal cells to LPS, we propose that, in addition to their role in direct and lysozyme-assisted killing of microbes, they have a role in feedback regulation of cytokine responses. We are currently developing variant peptides as therapeutics against antibiotic-resistant infections.

  16. Design and characterization of an acid-activated antimicrobial peptide.

    Science.gov (United States)

    Li, Lina; He, Jian; Eckert, Randal; Yarbrough, Daniel; Lux, Renate; Anderson, Maxwell; Shi, Wenyuan

    2010-01-01

    Dental caries is a microbial biofilm infection in which the metabolic activities of plaque bacteria result in a dramatic pH decrease and shift the demineralization/remineralization equilibrium on the tooth surface towards demineralization. In addition to causing a net loss in tooth minerals, creation of an acidic environment favors growth of acid-enduring and acid-generating species, which causes further reduction in the plaque pH. In this study, we developed a prototype antimicrobial peptide capable of achieving high activity exclusively at low environmental pH to target bacterial species like Streptococcus mutans that produce acid and thrive under the low pH conditions detrimental for tooth integrity. The features of clavanin A, a naturally occurring peptide rich in histidine and phenylalanine residues with pH-dependent antimicrobial activity, served as a design basis for these prototype 'acid-activated peptides' (AAPs). Employing the major cariogenic species S. mutans as a model system, the two AAPs characterized in this study exhibited a striking pH-dependent antimicrobial activity, which correlated well with the calculated charge distribution. This type of peptide represents a potential new way to combat dental caries. PMID:19878192

  17. Synthesis, characterization, antimicrobial activity and LPS-interaction properties of SB041, a novel dendrimeric peptide with antimicrobial properties.

    Science.gov (United States)

    Bruschi, Michela; Pirri, Giovanna; Giuliani, Andrea; Nicoletto, Silvia Fabiole; Baster, Izabela; Scorciapino, Mariano Andrea; Casu, Mariano; Rinaldi, Andrea C

    2010-08-01

    Multimeric peptides offer several advantages with respect to their monomeric counterparts, as increased activity and greater stability to peptidases and proteases. SB041 is a novel antimicrobial peptide with dendrimeric structure; it is a tetramer of pyrEKKIRVRLSA linked by a lysine core, with an amino valeric acid chain. Here, we report on its synthesis, NMR characterization, antimicrobial activity, and LPS-interaction properties. The peptide was especially active against Gram-negative strains, with a potency comparable (on molar basis) to that of lipopeptides colistin and polymixin B, but it also displayed some activity against selected Gram-positive strains. Following these indications, we investigated the efficacy of SB041 in binding Escherichia coli and Pseudomonas aeruginosa LPS in vitro and counteracting its biological effects in RAW-Blue cells, derived from RAW 264.7 macrophages. SB041 strongly bound purified LPS, especially that of E. coli, as proved by fluorescent displacement assay, and readily penetrated into LPS monolayers. However, the killing activity of SB041 against E. coli was not inhibited by increasing concentrations of LPS added to the medium. Checking the SB041 effect on LPS-induced activation of pattern recognition receptors (PRRs) in Raw-Blue cells revealed that while the peptide gave a statistically significant decrease in PRRs stimulation when RAW-Blue cells were challenged with P. aeruginosa LPS, the same was not seen when E. coli LPS was used to activate innate immune defense-like responses. Thus, as previously seen for other antimicrobial peptides, also for SB041 binding to LPS did not translate necessarily into LPS-neutralizing activity, suggesting that SB041-LPS interactions must be of complex nature.

  18. Multifunctional antimicrobial proteins and peptides: natural activators of immune systems.

    Science.gov (United States)

    Niyonsaba, François; Nagaoka, Isao; Ogawa, Hideoki; Okumura, Ko

    2009-01-01

    In addition to the physical barrier of the stratum corneum, cutaneous innate immunity also includes the release of various humoral mediators, such as cytokines and chemokines, recruitment and activation of phagocytes, and the production of antimicrobial proteins/peptides (AMPs). AMPs form an innate epithelial chemical shield, which provides a front-line component in innate immunity to inhibit microbial invasion; however, this might be an oversimplification of the diverse functions of these molecules. In fact, apart from exhibiting a broad spectrum of microbicidal properties, it is increasingly evident that AMPs display additional activities that are related to the stimulation and modulation of the cutaneous immune system. These diverse functions include chemoattraction and activation of immune and/or inflammatory cells, the production and release of cytokines and chemokines, acceleration of angiogenesis, promotion of wound healing, neutralization of harmful microbial products, and bridging of both innate and adaptive immunity. Thus, better understanding of the functions of AMPs in skin and identification of their signaling mechanisms may offer new strategies for the development of potential therapeutics for the treatment of infection- and/or inflammation-related skin diseases. Here, we briefly outline the structure, regulation of expression, and multifunctional roles of principal skin-derived AMPs.

  19. Resistance to antimicrobial peptides in Gram-negative bacteria.

    Science.gov (United States)

    Gruenheid, Samantha; Le Moual, Hervé

    2012-05-01

    Antimicrobial peptides (AMPs) are present in virtually all organisms and are an ancient and critical component of innate immunity. In mammals, AMPs are present in phagocytic cells, on body surfaces such as skin and mucosa, and in secretions and body fluids such as sweat, saliva, urine, and breast milk, consistent with their role as part of the first line of defense against a wide range of pathogenic microorganisms including bacteria, viruses, and fungi. AMPs are microbicidal and have also been shown to act as immunomodulators with chemoattractant and signaling activities. During the co-evolution of hosts and bacterial pathogens, bacteria have developed the ability to sense and initiate an adaptive response to AMPs to resist their bactericidal activity. Here, we review the various mechanisms used by Gram-negative bacteria to sense and resist AMP-mediated killing. These mechanisms play an important role in bacterial resistance to host-derived AMPs that are encountered during the course of infection. Bacterial resistance to AMPs should also be taken into consideration in the development and use of AMPs as anti-infective agents, for which there is currently a great deal of academic and commercial interest.

  20. Antimicrobial and Biophysical Properties of Surfactant Supplemented with an Antimicrobial Peptide for Treatment of Bacterial Pneumonia

    NARCIS (Netherlands)

    Banaschewski, Brandon J H; Veldhuizen, Edwin J A; Keating, Eleonora; Haagsman, Henk P; Zuo, Yi Y; Yamashita, Cory M; Veldhuizen, Ruud A W

    2015-01-01

    BACKGROUND: Antibiotic resistant bacterial infections represent an emerging health concern in clinical settings, and a lack of novel developments in the pharmaceutical pipeline is creating a "perfect storm" for multi-drug resistant bacterial infections. Antimicrobial peptides (AMPs) have been sugges

  1. The roles of antimicrobial peptides in innate host defense.

    Science.gov (United States)

    Diamond, Gill; Beckloff, Nicholas; Weinberg, Aaron; Kisich, Kevin O

    2009-01-01

    Antimicrobial peptides (AMPs) are multi-functional peptides whose fundamental biological role in vivo has been proposed to be the elimination of pathogenic microorganisms, including Gram-positive and -negative bacteria, fungi, and viruses. Genes encoding these peptides are expressed in a variety of cells in the host, including circulating phagocytic cells and mucosal epithelial cells, demonstrating a wide range of utility in the innate immune system. Expression of these genes is tightly regulated; they are induced by pathogens and cytokines as part of the host defense response, and they can be suppressed by bacterial virulence factors and environmental factors which can lead to increased susceptibility to infection. New research has also cast light on alternative functionalities, including immunomodulatory activities, which are related to their unique structural characteristics. These peptides represent not only an important component of innate host defense against microbial colonization and a link between innate and adaptive immunity, but also form a foundation for the development of new therapeutic agents.

  2. Cathelicidin peptide sheep myeloid antimicrobial peptide-29 prevents endotoxin-induced mortality in rat models of septic shock.

    Science.gov (United States)

    Giacometti, Andrea; Cirioni, Oscar; Ghiselli, Roberto; Mocchegiani, Federico; D'Amato, Giuseppina; Circo, Raffaella; Orlando, Fiorenza; Skerlavaj, Barbara; Silvestri, Carmela; Saba, Vittorio; Zanetti, Margherita; Scalise, Giorgio

    2004-01-15

    The present study was designed to investigate the antiendotoxin activity and therapeutic efficacy of sheep myeloid antimicrobial peptide (SMAP)-29, a cathelicidin-derived peptide. The in vitro ability of SMAP-29 to bind LPS from Escherichia coli 0111:B4 was determined using a sensitive limulus chromogenic assay. Two rat models of septic shock were performed: (1) rats were injected intraperitoneally with 1 mg E. coli 0111:B4 LPS and (2) intraabdominal sepsis was induced via cecal ligation and single puncture. All animals were randomized to receive parenterally isotonic sodium chloride solution, 1 mg/kg SMAP-29, 1 mg/kg polymyxin B or 20 mg/kg imipenem. The main outcome measures were: abdominal exudate and plasma bacterial growth, plasma endotoxin and tumor necrosis factor-alpha concentrations, and lethality. The in vitro study showed that SMAP-29 completely inhibited the LPS procoagulant activity at approximately 10 microM peptide concentration. The in vivo experiments showed that all compounds reduced the lethality when compared with control animals. SMAP-29 achieved a substantial decrease in endotoxin and tumor necrosis factor-alpha plasma concentrations when compared with imipenem and saline treatment and exhibited a slightly lower antimicrobial activity than imipenem. No statistically significant differences were noted between SMAP-29 and polymyxin B. SMAP-29, because of its double antiendotoxin and antimicrobial activities, could be an interesting compound for septic shock treatment. PMID:14563656

  3. Host defense peptides and their antimicrobial-immunomodulatory duality.

    Science.gov (United States)

    Steinstraesser, Lars; Kraneburg, Ursula; Jacobsen, Frank; Al-Benna, Sammy

    2011-03-01

    Host defence peptides (HDPs) are short cationic molecules produced by the immune systems of most multicellular organisms and play a central role as effector molecules of innate immunity. Host defence peptides have a wide range of biological activities from direct killing of invading pathogens to modulation of immunity and other biological responses of the host. HDPs have important functions in multiple, clinically relevant disease processes and their imbalanced expression is associated with pathology in different organ systems and cell types. Furthermore, HDPs are now evaluated as model molecules for the development of novel natural antibiotics and immunoregulatory compounds. This review provides an overview of HDPs focused on their antimicrobial-immunomodulatory duality.

  4. Bactericidal synergy of lysostaphin in combination with antimicrobial peptides.

    Science.gov (United States)

    Desbois, A P; Coote, P J

    2011-08-01

    Drug-resistant staphylococci constitute a serious problem that urgently requires the discovery of new therapeutic agents. There has been a resurgence in interest in using lysostaphin (a specific anti-staphylococcal enzyme) as a treatment for infections caused by these important pathogens. However, bacterial resistance to lysostaphin is a problem, but the use of a combination treatment may surmount this issue. In this present study, using viable counts from suspension incubations, lysostaphin is shown to be synergistically bactericidal in combination with various conventional antimicrobial peptides, the antimicrobial protein bovine lactoferrin, a lantibiotic (nisin), and certain lipopeptides used clinically (colistin, daptomycin and polymyxin B). Combinations that act in synergy are of clinical importance as these reduce the doses of the compounds needed for effective treatments and decrease the chances of resistance being selected. The use of lysostaphin in combination with a peptide may represent a new avenue in tackling drug-resistant staphylococci. PMID:21311938

  5. Access to new antimicrobial 4-methylumbelliferone derivatives

    Indian Academy of Sciences (India)

    Marwa Zayane; Anis Romdhane; Mejda Daami-Remadi; Hichem Ben Jannet

    2015-09-01

    Synthesis of some novel coumarin esters has been accomplished through iodine-catalyzed method using 4-methylumbelliferone as the starting material. Condensation of hydrazide, which was obtained in two steps from 4-methylumbelliferone, with some arylaldhydes provided hydrazone derivatives, while the reaction with phenylthioisocyanate leads to the thiosemicarbazide that evolved into two new compounds. Finally, condensation reaction of hydrazide with three diketones afforded new pyrrole and pyrazole derivatives. Structures of all synthesized compounds were established on the basis of spectroscopic methods including 1H NMR, 13C NMR and ES-HRMS. They were finally tested for their antimicrobial activity and the structure-activity relationship was discussed.

  6. Design and Characterization of an Acid-Activated Antimicrobial Peptide

    OpenAIRE

    Li, Lina; He, Jian; Eckert, Randal; Yarbrough, Daniel; Lux, Renate; Anderson, Maxwell; Shi, Wenyuan

    2009-01-01

    Dental caries is a microbial biofilm infection in which the metabolic activities of plaque bacteria result in a dramatic pH decrease and shift the demineralization/ remineralization equilibrium on the tooth surface towards demineralization. In addition to causing a net loss in tooth minerals creation of an acidic environment favors growth of acid enduring and acid generating species, which causes further reduction in the plaque pH. In this study we developed a prototype antimicrobial peptide ...

  7. Suppression of Antimicrobial Peptide Expression by Ureaplasma Species

    OpenAIRE

    Xiao, Li; Crabb, Donna M.; Dai, Yuling; Chen, Yuying; Ken B Waites; Atkinson, T. Prescott

    2014-01-01

    Ureaplasma species commonly colonize the adult urogenital tract and are implicated in invasive diseases of adults and neonates. Factors that permit the organisms to cause chronic colonization or infection are poorly understood. We sought to investigate whether host innate immune responses, specifically, antimicrobial peptides (AMPs), are involved in determining the outcome of Ureaplasma infections. THP-1 cells, a human monocytoid tumor line, were cocultured with Ureaplasma parvum and U. ureal...

  8. Short antimicrobial peptides as cosmetic ingredients to deter dermatological pathogens

    OpenAIRE

    Rahnamaeian, Mohammad; Vilcinskas, Andreas

    2015-01-01

    Antimicrobial peptides (AMPs) are components of the innate immune system in many species of animals. Their diverse spectrum of activity against microbial pathogens, both as innate defense molecules and immunomodulators, makes them attractive candidates for the development of a new generation of antibiotics. Although the potential immunogenicity of AMPs means they are not suitable for injection and their susceptibility to digestive peptidases is likely to reduce their oral efficacy, they are i...

  9. Defense peptides secreted by helminth pathogens: antimicrobial and/or immunomodulator molecules?

    Directory of Open Access Journals (Sweden)

    Sophie eCotton

    2012-08-01

    Full Text Available Host defense peptides (HDPs are an evolutionarily conserved component of the innate immune response found in all living species. They possess antimicrobial activities against a broad range of organisms including bacteria, fungi, eukaryotic parasites and viruses. HDPs also have the ability to enhance immune responses by acting as immunomodulators. We discovered a new family of HDPs derived from pathogenic helminthes (worms that cause enormous disease in animals and humans worldwide. The discovery of these peptides was based on their similar biochemical and functional characteristics to the human defense peptide LL-37. We propose that these new peptides modulate the immune response via molecular mimicry of mammalian HDPs thus providing a mechanism behind the anti-inflammatory properties of helminth infections.

  10. Resistance of Antimicrobial Peptide Gene Transgenic Rice to Bacterial Blight

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; WU Chao; LIU Mei; LIU Xu-ri; Hu Guo-cheng; SI Hua-min; SUN Zong-xiu; LIU Wen-zhen; Fu Ya-ping

    2011-01-01

    Antimierobial peptide is a polypeptide with antimicrobial activity.Antimicrobial peptide genes Np3 and Np5 from Chinese shrimp (Fenneropenaeus Chinensis) were integrated into Oryza sativa L.subsp.japonica cv.Aichi ashahi by Agrobacterium mediated transformation system.PCR analysis showed that the positive ratios of Np3 and Np5 were 36% and 45% in T0 generation,respectively.RT-PCR analysis showed that the antimicrobial peptide genes were expressed in T1 generation,and there was no obvious difference in agronomic traits between transgenic plants and non-transgenic plants.Four Np3 and Np5 transgenic lines in T1 generation were inoculated with ×anthomonas oryzae pv.oryzae strain CR4,and all the four transgenic lines had significantly enhanced resistance to bacterial blight caused by the strain CR4.The Np5 transgenic lines also showed higher resistance to bacterial blight caused by strains JS97-2,Zhe 173 and OS-225.It is suggested that transgenic lines with Np5 gene might possess broad spectrum resistance to rice bacterial blight.

  11. Diversity, evolution and medical applications of insect antimicrobial peptides.

    Science.gov (United States)

    Mylonakis, Eleftherios; Podsiadlowski, Lars; Muhammed, Maged; Vilcinskas, Andreas

    2016-05-26

    Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolution of insect AMPs by mapping their phylogenetic distribution, allowing us to predict the evolutionary origins of selected AMP families and to identify evolutionarily conserved and taxon-specific families. Furthermore, we highlight the use of the nematode Caenorhabditis elegans as a whole-animal model in high-throughput screening methods to identify AMPs with efficacy against human pathogens, including Acinetobacter baumanii and methicillin-resistant Staphylococcus aureus We also discuss the potential medical applications of AMPs, including their use as alternatives for conventional antibiotics in ectopic therapies, their combined use with antibiotics to restore the susceptibility of multidrug-resistant pathogens, and their use as templates for the rational design of peptidomimetic drugs that overcome the disadvantages of therapeutic peptides.The article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160593

  12. Diversity, evolution and medical applications of insect antimicrobial peptides.

    Science.gov (United States)

    Mylonakis, Eleftherios; Podsiadlowski, Lars; Muhammed, Maged; Vilcinskas, Andreas

    2016-05-26

    Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolution of insect AMPs by mapping their phylogenetic distribution, allowing us to predict the evolutionary origins of selected AMP families and to identify evolutionarily conserved and taxon-specific families. Furthermore, we highlight the use of the nematode Caenorhabditis elegans as a whole-animal model in high-throughput screening methods to identify AMPs with efficacy against human pathogens, including Acinetobacter baumanii and methicillin-resistant Staphylococcus aureus We also discuss the potential medical applications of AMPs, including their use as alternatives for conventional antibiotics in ectopic therapies, their combined use with antibiotics to restore the susceptibility of multidrug-resistant pathogens, and their use as templates for the rational design of peptidomimetic drugs that overcome the disadvantages of therapeutic peptides.The article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.

  13. Quantitative single-vesicle analysis of antimicrobial peptide-induced leakage

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Ehrlich, Nicky; Henriksen, Jonas Rosager;

    2013-01-01

    Although the research field of antimicrobial peptides has attracted considerable scientific attention in the past decades, the microbicidal mechanisms of antimicrobial peptides still remain elusive. One of the keys to a more profound comprehension of the function of these peptides is a deeper...

  14. Sap transporter mediated import and subsequent degradation of antimicrobial peptides in Haemophilus.

    Directory of Open Access Journals (Sweden)

    Catherine L Shelton

    2011-11-01

    Full Text Available Antimicrobial peptides (AMPs contribute to host innate immune defense and are a critical component to control bacterial infection. Nontypeable Haemophilus influenzae (NTHI is a commensal inhabitant of the human nasopharyngeal mucosa, yet is commonly associated with opportunistic infections of the upper and lower respiratory tracts. An important aspect of NTHI virulence is the ability to avert bactericidal effects of host-derived antimicrobial peptides (AMPs. The Sap (sensitivity to antimicrobial peptides ABC transporter equips NTHI to resist AMPs, although the mechanism of this resistance has remained undefined. We previously determined that the periplasmic binding protein SapA bound AMPs and was required for NTHI virulence in vivo. We now demonstrate, by antibody-mediated neutralization of AMP in vivo, that SapA functions to directly counter AMP lethality during NTHI infection. We hypothesized that SapA would deliver AMPs to the Sap inner membrane complex for transport into the bacterial cytoplasm. We observed that AMPs localize to the bacterial cytoplasm of the parental NTHI strain and were susceptible to cytoplasmic peptidase activity. In striking contrast, AMPs accumulated in the periplasm of bacteria lacking a functional Sap permease complex. These data support a mechanism of Sap mediated import of AMPs, a novel strategy to reduce periplasmic and inner membrane accumulation of these host defense peptides.

  15. Antimicrobial activities of chicken β-defensin (4 and 10) peptides against pathogenic bacteria and fungi.

    Science.gov (United States)

    Yacoub, Haitham A; Elazzazy, Ahmed M; Abuzinadah, Osama A H; Al-Hejin, Ahmed M; Mahmoud, Maged M; Harakeh, Steve M

    2015-01-01

    Host Defense Peptides (HDPs) are small cationic peptides found in several organisms. They play a vital role in innate immunity response and immunomodulatory stimulation. This investigation was designed to study the antimicrobial activities of β-defensin peptide-4 (sAvBD-4) and 10 (sAvBD-4) derived from chickens against pathogenic organisms including bacteria and fungi. Ten bacterial strains and three fungal species were used in investigation. The results showed that the sAvBD-10 displayed a higher bactericidal potency against all the tested bacterial strains than that of sAvBD-4. The exhibited bactericidal activity was significant against almost the different bacterial strains at different peptide concentrations except for that of Pseudomonas aeruginosa (P. aeruginosa) and Streptococcus bovis (Str. bovis) strains where a moderate effect was noted. Both peptides were effective in the inactivation of fungal species tested yielding a killing rate of up to 95%. The results revealed that the synthetic peptides were resistant to salt at a concentration of 50 mM NaCl. However, they lost antimicrobial potency when applied in the presence of high salt concentrations. Based on blood hemolysis studies, a little hemolytic effect was showed in the case of both peptides even when applied at high concentrations. The data obtained from this study indicated that synthetic avian peptides exhibit strong antibacterial and antifungal activity. In conclusion, future work and research should be tailored to a better understanding of the mechanisms of action of those peptides and their potential use in the pharmaceutical industry to help reduce the incidence and impact of infectious agent and be marketed as a naturally occurring antibiotic.

  16. The use of versatile plant antimicrobial peptides in agribusiness and human health.

    Science.gov (United States)

    de Souza Cândido, Elizabete; e Silva Cardoso, Marlon Henrique; Sousa, Daniel Amaro; Viana, Juliane Cançado; de Oliveira-Júnior, Nelson Gomes; Miranda, Vívian; Franco, Octávio Luiz

    2014-05-01

    Plant immune responses involve a wide diversity of physiological reactions that are induced by the recognition of pathogens, such as hypersensitive responses, cell wall modifications, and the synthesis of antimicrobial molecules including antimicrobial peptides (AMPs). These proteinaceous molecules have been widely studied, presenting peculiar characteristics such as conserved domains and a conserved disulfide bond pattern. Currently, many AMP classes with diverse modes of action are known, having been isolated from a large number of organisms. Plant AMPs comprise an interesting source of studies nowadays, and among these there are reports of different classes, including defensins, albumins, cyclotides, snakins and several others. These peptides have been widely used in works that pursue human disease control, including nosocomial infections, as well as for agricultural purposes. In this context, this review will focus on the relevance of the structural-function relations of AMPs derived from plants and their proper use in applications for human health and agribusiness.

  17. Purification Technology and Antimicrobial Activity Analysis of Antimicrobial Peptide from Ovotransferrin

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tie-hua; ZHENG Jian; YE Hai-qing; YU Ya-li; ZHAO Ping; LIU Jing-bo

    2011-01-01

    Antibacterial peptides mixture purified from Ovotransferrin by pepsin digest was used as the raw material.Peptide sections with good antibacterial activity were determined after bacteriostasis experiments, its molecular weight and amino acid composition were analyzed. The results of experiments indicate that with Sephadex G-50 and distilled water as mobile phase, detection wavelength 220 nm, flow rate 1.5 mL/min, sample density 0.2 g/mL, and volume 0.2 mL are the optimal conditions. Bacteriostasis experiments of the fraction of purified peaks were carried out and the result was: peak 1>peak 3>peak 2; the molecular weight of peak 1 was about 3015 by high performance liquid chromatography; active peptide possessed positive charges by amino acid analysis, its cationic characteristics are in accordance with the nature of antimicrobial peptides.

  18. The human cathelicidin antimicrobial peptide LL-37 as a potential treatment for polymicrobial infected wounds.

    Directory of Open Access Journals (Sweden)

    Allen J Duplantier

    2013-07-01

    Full Text Available Diabetic patients often have ulcers on their lower-limbs that are infected by multiple biofilm-forming genera of bacteria, and the elimination of the biofilm has proven highly successful in resolving such wounds in patients. To that end, antimicrobial peptides have shown potential as a new anti-biofilm approach. The single human cathelicidin peptide LL-37 has been shown to have antimicrobial and antibiofilm activity against multiple gram-positive and gram-negative human pathogens, and have wound-healing effects on the host. The combination of the anti-biofilm effect and wound-healing properties of LL-37 may make it highly effective in resolving polymicrobially infected wounds when topically applied. Such a peptide or its derivatives could be a platform from which to develop new therapeutic strategies to treat biofilm-mediated infections of wounds. This review summarizes known mechanisms that regulate the endogenous levels of LL-37 and discusses the antibiofilm, antibacterial and immunological effects of deficient versus excessive concentrations of LL-37 within the wound environment. Here, we review recent advances in understanding the therapeutic potential of this peptide and other clinically advanced peptides as a potential topical treatment for polymicrobial infected wounds.

  19. Gram-positive bacterial cell envelopes: The impact on the activity of antimicrobial peptides.

    Science.gov (United States)

    Malanovic, Nermina; Lohner, Karl

    2016-05-01

    A number of cationic antimicrobial peptides, effectors of innate immunity, are supposed to act at the cytoplasmic membrane leading to permeabilization and eventually membrane disruption. Thereby, interaction of antimicrobial peptides with anionic membrane phospholipids is considered to be a key factor in killing of bacteria. Recently, evidence was provided that killing takes place only when bacterial cell membranes are completely saturated with peptides. This adds to an ongoing debate, which role cell wall components such as peptidoglycan, lipoteichoic acid and lipopolysaccharide may play in the killing event, i.e. if they rather entrap or facilitate antimicrobial peptides access to the cytoplasmic membrane. Therefore, in this review we focused on the impact of Gram-positive cell wall components for the mode of action and activity of antimicrobial peptides as well as in innate immunity. This led us to conclude that interaction of antimicrobial peptides with peptidoglycan may not contribute to a reduction of their antimicrobial activity, whereas interaction with anionic lipoteichoic acids may reduce the local concentration of antimicrobial peptides on the cytoplasmic membrane necessary for sufficient destabilization of the membranes and bacterial killing. Further affinity studies of antimicrobial peptides toward the different cell wall as well as membrane components will be needed to address this problem on a quantitative level. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert.

  20. The specificity of protection against cationic antimicrobial peptides by lactoferrin binding protein B.

    Science.gov (United States)

    Morgenthau, Ari; Partha, Sarathy K; Adamiak, Paul; Schryvers, Anthony B

    2014-10-01

    A variety of Gram-negative pathogens possess host-specific lactoferrin (Lf) receptors that mediate the acquisition of iron from host Lf. The integral membrane protein component of the receptor, lactoferrin binding protein A specifically binds host Lf and is required for acquisition of iron from Lf. In contrast, the role of the bi-lobed surface lipoprotein, lactoferrin binding protein B (LbpB), in Lf binding and iron acquisition is uncertain. A common feature of LbpBs from most species is the presence of clusters of negatively charged amino acids in the protein's C-terminal lobe. Recently it has been shown that the negatively charged regions from the Neisseria meningitidis LbpB are responsible for protecting against an 11 amino acid cationic antimicrobial peptide (CAP), lactoferricin (Lfcin), derived from human Lf. In this study we investigated whether the LbpB confers resistance to other CAPs since N. meningitidis is likely to encounter other CAPs from the host. LbpB provided protection against the cathelicidin derived peptide, cathelicidin related antimicrobial peptide (mCRAMP), but did not confer protection against Tritrp 1 or LL37 under our experimental conditions. When tested against a range of rationally designed synthetic peptides, LbpB was shown to protect against IDR-1002 and IDR-0018 but not against HH-2 or HHC10. PMID:25038734

  1. Antimicrobial peptides: key components of the innate immune system.

    Science.gov (United States)

    Pasupuleti, Mukesh; Schmidtchen, Artur; Malmsten, Martin

    2012-06-01

    Life-threatening infectious diseases are on their way to cause a worldwide crisis, as treating them effectively is becoming increasingly difficult due to the emergence of antibiotic resistant strains. Antimicrobial peptides (AMPs) form an ancient type of innate immunity found universally in all living organisms, providing a principal first-line of defense against the invading pathogens. The unique diverse function and architecture of AMPs has attracted considerable attention by scientists, both in terms of understanding the basic biology of the innate immune system, and as a tool in the design of molecular templates for new anti-infective drugs. AMPs are gene-encoded short (antimicrobial activity. AMPs have been the subject of natural evolution, as have the microbes, for hundreds of millions of years. Despite this long history of co-evolution, AMPs have not lost their ability to kill or inhibit the microbes totally, nor have the microbes learnt to avoid the lethal punch of AMPs. AMPs therefore have potential to provide an important breakthrough and form the basis for a new class of antibiotics. In this review, we would like to give an overview of cationic antimicrobial peptides, origin, structure, functions, and mode of action of AMPs, which are highly expressed and found in humans, as well as a brief discussion about widely abundant, well characterized AMPs in mammals, in addition to pharmaceutical aspects and the additional functions of AMPs.

  2. Comparative Evaluation of the Antimicrobial Activity of Different Antimicrobial Peptides against a Range of Pathogenic Bacteria.

    Directory of Open Access Journals (Sweden)

    Anna Ebbensgaard

    Full Text Available The rapid emergence of resistance to classical antibiotics has increased the interest in novel antimicrobial compounds. Antimicrobial peptides (AMPs represent an attractive alternative to classical antibiotics and a number of different studies have reported antimicrobial activity data of various AMPs, but there is only limited comparative data available. The mode of action for many AMPs is largely unknown even though several models have suggested that the lipopolysaccharides (LPS play a crucial role in the attraction and attachment of the AMP to the bacterial membrane in Gram-negative bacteria. We compared the potency of Cap18, Cap11, Cap11-1-18m2, Cecropin P1, Cecropin B, Bac2A, Bac2A-NH2, Sub5-NH2, Indolicidin, Melittin, Myxinidin, Myxinidin-NH2, Pyrrhocoricin, Apidaecin and Metalnikowin I towards Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Aeromonas salmonicida, Listeria monocytogenes, Campylobacter jejuni, Flavobacterium psychrophilum, Salmonella typhimurium and Yersinia ruckeri by minimal inhibitory concentration (MIC determinations. Additional characteristics such as cytotoxicity, thermo and protease stability were measured and compared among the different peptides. Further, the antimicrobial activity of a selection of cationic AMPs was investigated in various E. coli LPS mutants.Of all the tested AMPs, Cap18 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria. In addition, Cap18 is highly thermostable and showed no cytotoxic effect in a hemolytic assay, measured at the concentration used. However, Cap18 is, as most of the tested AMPs, sensitive to proteolytic digestion in vitro. Thus, Cap18 is an excellent candidate for further development into practical use; however, modifications that should reduce the protease sensitivity would be needed. In addition, our findings from analyzing LPS mutant strains suggest that the core oligosaccharide of the LPS

  3. Antimicrobial Peptides as Mediators of Innate Immunity in Teleosts

    Directory of Open Access Journals (Sweden)

    Barbara A. Katzenback

    2015-09-01

    Full Text Available Antimicrobial peptides (AMPs have been identified throughout the metazoa suggesting their evolutionarily conserved nature and their presence in teleosts is no exception. AMPs are short (18–46 amino acids, usually cationic, amphipathic peptides. While AMPs are diverse in amino acid sequence, with no two AMPs being identical, they collectively appear to have conserved functions in the innate immunity of animals towards the pathogens they encounter in their environment. Fish AMPs are upregulated in response to pathogens and appear to have direct broad-spectrum antimicrobial activity towards both human and fish pathogens. However, an emerging role for AMPs as immunomodulatory molecules has become apparent—the ability of AMPs to activate the innate immune system sheds light onto the multifaceted capacity of these small peptides to combat pathogens through direct and indirect means. Herein, this review focuses on the role of teleost AMPs as modulators of the innate immune system and their regulation in response to pathogens or other exogenous molecules. The capacity to regulate AMP expression by exogenous factors may prove useful in modulating AMP expression in fish to prevent disease, particularly in aquaculture settings where crowded conditions and environmental stress pre-dispose these fish to infection.

  4. Antimicrobial Peptides as Mediators of Innate Immunity in Teleosts.

    Science.gov (United States)

    Katzenback, Barbara A

    2015-09-25

    Antimicrobial peptides (AMPs) have been identified throughout the metazoa suggesting their evolutionarily conserved nature and their presence in teleosts is no exception. AMPs are short (18-46 amino acids), usually cationic, amphipathic peptides. While AMPs are diverse in amino acid sequence, with no two AMPs being identical, they collectively appear to have conserved functions in the innate immunity of animals towards the pathogens they encounter in their environment. Fish AMPs are upregulated in response to pathogens and appear to have direct broad-spectrum antimicrobial activity towards both human and fish pathogens. However, an emerging role for AMPs as immunomodulatory molecules has become apparent-the ability of AMPs to activate the innate immune system sheds light onto the multifaceted capacity of these small peptides to combat pathogens through direct and indirect means. Herein, this review focuses on the role of teleost AMPs as modulators of the innate immune system and their regulation in response to pathogens or other exogenous molecules. The capacity to regulate AMP expression by exogenous factors may prove useful in modulating AMP expression in fish to prevent disease, particularly in aquaculture settings where crowded conditions and environmental stress pre-dispose these fish to infection.

  5. Expression pattern of arenicins - the antimicrobial peptides of polychaete Arenicolamarina

    Directory of Open Access Journals (Sweden)

    Arina L. Maltseva

    2014-12-01

    Full Text Available Immune responses of invertebrate animals are mediated through innate mechanisms, among which production of antimicrobial peptides play an important role. Although evolutionary Polychaetes represent an interesting group closely related to a putative common ancestor of other coelomates, their immune mechanisms still remain scarcely investigated. Previously our group has identified arenicins - new antimicrobial peptides of the lugworm Arenicola marina, since then these peptides were thoroughly characterized in terms of their structure and inhibitory potential. In the present study we addressed the question of the physiological functions of arenicins in the lugworm body. Using molecular and immunocytochemical methods we demonstrated that arencins are expressed in the wide range of the lugworm tissues - coelomocytes, body wall, extravasal tissue and the gut. The expression of arenicins is constitutive and does not depend on stimulation of various infectious stimuli. Most intensively arenicins are produced by mature coelomocytes where they function as killing agents inside the phagolysosome. In the gut and the body wall epithelia arenicins are released from producing cells via secretion as they are found both inside the epithelial cells and in the contents of the cuticle. Collectively our study showed that arenicins are found in different body compartments responsible for providing a first line of defence against infections, which implies their important role as key components of both epithelial and systemic branches of host defence.

  6. The Role of Antimicrobial Peptides in Preventing Multidrug-Resistant Bacterial Infections and Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Kyung-Soo Hahm

    2011-09-01

    Full Text Available Over the last decade, decreasing effectiveness of conventional antimicrobial-drugs has caused serious problems due to the rapid emergence of multidrug-resistant pathogens. Furthermore, biofilms, which are microbial communities that cause serious chronic infections and dental plaque, form environments that enhance antimicrobial resistance. As a result, there is a continuous search to overcome or control such problems, which has resulted in antimicrobial peptides being considered as an alternative to conventional drugs. Antimicrobial peptides are ancient host defense effector molecules in living organisms. These peptides have been identified in diverse organisms and synthetically developed by using peptidomimic techniques. This review was conducted to demonstrate the mode of action by which antimicrobial peptides combat multidrug-resistant bacteria and prevent biofilm formation and to introduce clinical uses of these compounds for chronic disease, medical devices, and oral health. In addition, combinations of antimicrobial peptides and conventional drugs were considered due to their synergetic effects and low cost for therapeutic treatment.

  7. Importance of Tryptophan in Transforming an Amphipathic Peptide into a Pseudomonas aeruginosa-Targeted Antimicrobial Peptide.

    Directory of Open Access Journals (Sweden)

    Xin Zhu

    Full Text Available Here, we found that simple substitution of amino acids in the middle position of the hydrophobic face of an amphipathic peptide RI16 with tryptophan (T9W considerably transformed into an antimicrobial peptide specifically targeting Pseudomonas aeruginosa. Minimal inhibitory concentration (MIC results demonstrated that T9W had a strong and specifically antimicrobial activity against P. aeruginosa, including antibiotic-resistant strains, but was not active against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Staphyfococcus epidermidis. Fluorescent spectroscopic assays indicated that T9W interacted with the membrane of P. aeruginosa, depolarizing the outer and the inner membrane of bacterial cells. Salt susceptibility assay showed that T9W still maintained its strong anti-pseudomonas activity in the presence of salts at physiological concentrations, and in hemolytic and MTT assays T9W also showed no toxicity against human blood cells and macrophages. In vivo assay demonstrated that T9W also displayed no toxicity to Chinese Kun Ming (KM mice. Furthermore, the strong antibiofilm activity was also observed with the peptide T9W, which decreased the percentage of biomass formation in a dose-dependent manner. Overall, these findings indicated that design of single-pathogen antimicrobial agents can be achieved by simple amino acid mutation in naturally occurring peptide sequences and this study suggested a model of optimization/design of anti-pseudomonas drugs in which the tryptophan residue was a conserved element.

  8. Antimicrobial potential of lycosin-I, a cationic and amphiphilic peptide from the venom of the spider Lycosa singorensis.

    Science.gov (United States)

    Tan, H; Ding, X; Meng, S; Liu, C; Wang, H; Xia, L; Liu, Z; Liang, S

    2013-07-01

    Antimicrobial peptides (AMPs) are significant components of the innate immune system and play indispensable roles in the resistance to bacterial infection. Here, we investigated the antimicrobial activity of lycosin-I, a 24-residue cationic anticancer peptide derived from Lycosa singorensis with high structural similarity to several cationic and amphiphilic antimicrobial peptides. The antimicrobial activity of lycosin-I against 27 strains of microbes including bacteria and fungi was examined and compared with that of the Xenopus-derived AMP magainin 2 using a microdilution assay. Lycosin-I inhibited the growth of most microorganisms at low micromolar concentrations, and was a more potent inhibitor than magainin 2. Lycosin-I showed rapid, selective and broad-spectrum bactericidal activity and a synergistic effect with traditional antibiotics. In vivo, it showed potent bactericidal activity in a mouse thigh infection model. High Mg2+ concentrations reduced the antibacterial effect of lycosin-I, implying that the peptide might directly interact with the bacterial cell membrane. Uptake of the fluorogenic dye SYTOX and changes in the surface of lycosin-Itreated bacterial cells observed by scanning electron microscopy confirmed that lycosin-I permeabilized the cell membrane, resulting in the rapid bactericidal effect. Taken together, our findings indicate that lycosin-I is a promising peptide with the potential for the development of novel antibacterial agents.

  9. Dynamical and Phase Behavior of a Phospholipid Membrane Altered by an Antimicrobial Peptide at Low Concentration.

    Science.gov (United States)

    Sharma, V K; Mamontov, E; Tyagi, M; Qian, S; Rai, D K; Urban, V S

    2016-07-01

    The mechanism of action of antimicrobial peptides is traditionally attributed to the formation of pores in the lipid cell membranes of pathogens, which requires a substantial peptide to lipid ratio. However, using incoherent neutron scattering, we show that even at a concentration too low for pore formation, an archetypal antimicrobial peptide, melittin, disrupts the regular phase behavior of the microscopic dynamics in a phospholipid membrane, dimyristoylphosphatidylcholine (DMPC). At the same time, another antimicrobial peptide, alamethicin, does not exert a similar effect on the DMPC microscopic dynamics. The melittin-altered lateral motion of DMPC at physiological temperature no longer resembles the fluid-phase behavior characteristic of functional membranes of the living cells. The disruptive effect demonstrated by melittin even at low concentrations reveals a new mechanism of antimicrobial action relevant in more realistic scenarios, when peptide concentration is not as high as would be required for pore formation, which may facilitate treatment with antimicrobial peptides. PMID:27232190

  10. Design of host defence peptides for antimicrobial and immunity enhancing activities.

    Science.gov (United States)

    McPhee, Joseph B; Scott, Monisha G; Hancock, Robert E W

    2005-05-01

    Host defense peptides are a vital component of the innate immune systems of humans, other mammals, amphibians, and arthropods. The related cationic antimicrobial peptides are also produced by many species of bacteria and function as part of the antimicrobial arsenal to help the producing organism reduce competition for resources from sensitive species. The antimicrobial activities of many of these peptides have been extensively characterized and the structural requirements for these activities are also becoming increasingly clear. In addition to their known antimicrobial role, many host defense peptides are also involved in a plethora of immune functions in the host. In this review, we examine the role of structure in determining antimicrobial activity of certain prototypical cationic peptides and ways that bacteria have evolved to usurp these activities. We also review recent literature on what structural components are related to these immunomodulatory effects. It must be stressed however that these studies, and the area of peptide research, are still in their infancy.

  11. Membrane poration by antimicrobial peptides combining atomistic and coarse-grained descriptions

    NARCIS (Netherlands)

    Rzepiela, Andrzej J.; Sengupta, Durba; Goga, Nicolae; Marrink, Siewert J.

    2010-01-01

    Antimicrobial peptides (AMPs) comprise a large family of peptides that include small cationic peptides, such as magainins, which permeabilize lipid membranes. Previous atomistic level simulations of magainin-H2 peptides show that they act by forming toroidal transmembrane pores. However, due to the

  12. In vivo expression of antimicrobial peptides in atopic dermatitis

    DEFF Research Database (Denmark)

    Clausen, Maja-Lisa; Slotved, Hans-Christian; Krogfelt, Karen A.;

    2016-01-01

    The aim of this review is to present findings on expression of antimicrobial peptides (AMPs) in atopic dermatitis (AD) skin, focusing only on in vivo studies, and to discuss differences in results obtained using various skin sampling techniques and different methodology for analysis of AMPs. The ....... AMPs are important components of the skin as a defense against infections, and despite much research, the clinical importance of the effect of common treatments, including systemic treatments for AD and the interplay between AMPs and the skin microbiome, is still largely unknown....

  13. Short antimicrobial peptides as cosmetic ingredients to deter dermatological pathogens.

    Science.gov (United States)

    Rahnamaeian, Mohammad; Vilcinskas, Andreas

    2015-11-01

    Antimicrobial peptides (AMPs) are components of the innate immune system in many species of animals. Their diverse spectrum of activity against microbial pathogens, both as innate defense molecules and immunomodulators, makes them attractive candidates for the development of a new generation of antibiotics. Although the potential immunogenicity of AMPs means they are not suitable for injection and their susceptibility to digestive peptidases is likely to reduce their oral efficacy, they are ideal for topical formulations such as lotions, creams, shampoos, and wound dressings and could therefore be valuable products for the cosmetic industry. In this context, short AMPs (care products. PMID:26307444

  14. Aliphatic acid-conjugated antimicrobial peptides--potential agents with anti-tumor, multidrug resistance-reversing activity and enhanced stability.

    Science.gov (United States)

    Deng, Xin; Qiu, Qianqian; Ma, Ke; Wang, Xuekun; Huang, Wenlong; Qian, Hai

    2015-07-28

    Compared with traditional therapeutics, antimicrobial peptides as novel anti-tumor agents have prominent advantages of higher specificity and circumvention of multi-drug resistance. In a previous study, we found that B1, an antimicrobial peptide derived from Cathelicidin-BF15, presented specific anti-tumor activity against several tumor cells. Since aliphatic chain-conjugated peptides have shown ameliorative activity and stability, we conjugated aliphatic acids with different lengths to the amino terminal of B1. All the conjugated peptides exhibited improved anti-tumor activity over B1. Further investigations revealed that the peptides were capable of disrupting the cell membrane, stimulating cytochrome c release into the cytosol, which results in apoptosis. The peptides also acted against multidrug resistant cells and had multidrug resistance-reversing effects. Additionally, conjugation of aliphatic acid enhanced the peptide stability in plasma. In summary, aliphatic acid-modified peptides might be promising anti-tumor agents in the future. PMID:26083110

  15. Antibacterial Peptide Nucleic Acid-Antimicrobial Peptide (PNA-AMP) Conjugates

    DEFF Research Database (Denmark)

    Hansen, Anna Mette; Bonke, Gitte; Larsen, Camilla Josephine;

    2016-01-01

    Antisense peptide nucleic acid (PNA) oligomers constitute a novel class of potential antibiotics that inhibit bacterial growth via specific knockdown of essential gene expression. However, discovery of efficient, nontoxic delivery vehicles for such PNA oligomers has remained a challenge....... In the present study we show that antimicrobial peptides (AMPs) with an intracellular mode of action can be efficient vehicles for bacterial delivery of an antibacterial PNA targeting the essential acpP gene. The results demonstrate that buforin 2-A (BF2-A), drosocin, oncocin 10, Pep-1-K, KLW-9,13-a, (P59→W59...

  16. Antimicrobial peptides initiate IL-1 beta posttranslational processing: a novel role beyond innate immunity.

    Science.gov (United States)

    Perregaux, David G; Bhavsar, Kanan; Contillo, Len; Shi, Jishu; Gabel, Christopher A

    2002-03-15

    Human monocytes stimulated with LPS produce large quantities of prointerleukin-1beta, but little of this cytokine product is released extracellularly as the mature biologically active species. To demonstrate efficient proteolytic cleavage and export, cytokine-producing cells require a secondary effector stimulus. In an attempt to identify agents that may serve as initiators of IL-1beta posttranslational processing in vivo, LPS-activated human monocytes were treated with several individual antimicrobial peptides. Two peptides derived from porcine neutrophils, protegrin (PTG)-1 and PTG-3, promoted rapid and efficient release of mature IL-1beta. The PTG-mediated response engaged a mechanism similar to that initiated by extracellular ATP acting via the P2X(7) receptor. Thus, both processes were disrupted by a caspase inhibitor, both were sensitive to ethacrynic acid and CP-424,174, two pharmacological agents that suppress posttranslational processing, and both were negated by elevation of extracellular potassium. Moreover, the PTGs, like ATP, promoted a dramatic change in monocyte morphology and a loss of membrane latency. The PTG response was concentration dependent and was influenced profoundly by components within the culture medium. In contrast, porcine neutrophil antimicrobial peptides PR-26 and PR-39 did not initiate IL-1beta posttranslational processing. The human defensin HNP-1 and the frog peptide magainin 1 elicited export of 17-kDa IL-1beta, but these agents were less efficient than PTGs. As a result of this ability to promote release of potent proinflammatory cytokines such as IL-1beta, select antimicrobial peptides may possess important immunomodulatory functions that extend beyond innate immunity.

  17. Structure-dependent charge density as a determinant of antimicrobial activity of peptide analogues of defensin.

    Science.gov (United States)

    Bai, Yang; Liu, Shouping; Jiang, Ping; Zhou, Lei; Li, Jing; Tang, Charles; Verma, Chandra; Mu, Yuguang; Beuerman, Roger W; Pervushin, Konstantin

    2009-08-01

    Defensins are small (3-5 kDa) cysteine-rich cationic proteins found in both vertebrates and invertebrates constituting the front line of host innate immunity. Despite intensive research, bactericidal and cytotoxic mechanisms of defensins are still largely unknown. Moreover, we recently demonstrated that small peptides derived from defensins are even more potent bactericidal agents with less toxicity toward host cells. In this paper, structures of three C-terminal (R36-K45) analogues of human beta-defensin-3 were studied by 1H NMR spectroscopy and extensive molecular dynamics simulations. Because of indications that these peptides might target the inner bacterial membrane, they were reconstituted in dodecylphosphocholine or dodecylphosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] mixed micelles, and lipid bicelles mimicking the phospholipid-constituted bilayer membrane of mammalian and bacterial cells. The results show that the binding affinity and partitioning into the lipid phase and the ability to dimerize and accrete well-defined structures upon interactions with lipid membranes contribute to compactization of positive charges within peptide oligomers. The peptide charge density, mediated by corresponding three-dimensional structures, was found to directly correlate with the antimicrobial activity. These novel observations may provide a new rationale for the design of improved antimicrobial agents.

  18. The Molecular Basis for Antimicrobial Activity of Pore-Forming Cyclic Peptides

    NARCIS (Netherlands)

    Cirac, Anna D.; Moiset, Gemma; Mika, Jacek T.; Kocer, Armagan; Salvador, Pedro; Poolman, Bert; Marrink, Siewert J.; Sengupta, Durba

    2011-01-01

    The mechanism of action of antimicrobial peptides is, to our knowledge, still poorly understood. To probe the biophysical characteristics that confer activity, we present here a molecular-dynamics and biophysical study of a cyclic antimicrobial peptide and its inactive linear analog. In the simulati

  19. Expression profiles of seven channel catfish antimicrobial peptides in response to Edwardsiella ictaluri infection

    Science.gov (United States)

    Using quantitative PCR technique, the relative transcriptional levels of seven channel catfish antimicrobial peptide (AMP) genes [NK-lysin type 1, NK-lysin type 2, NK-lysin type 3, bactericidal permeability-increasing protein (BPI), cathepsin D, hepcidin, and liver-expressed antimicrobial peptide 2 ...

  20. 抗菌肽histatherin研究进展%Research Progress of Antimicrobial Peptide Histatherin

    Institute of Scientific and Technical Information of China (English)

    高帅; 鞠志花; 宿烽; 王长法

    2011-01-01

    抗菌肽产于机体组织、具有广谱抗菌活性和独特抗菌的机制.对抗菌肽的研究有助于开发抗菌肽药物、进行动物抗性育种和培育抗菌肽转基因动物.论文对一种新的牛抗菌肽histatherin的研究进展进行概述.%As the drug-resistance and challenge to food safety caused by the abuse of antibiotics is becoming serious , more and more attentions have been attracted to the antimicrobial peptides, which has characteristics of antimicrobial mechanism and wide antimicrobial spectrum. The research on antimicrobial peptides will contribute to antimicrobial peptides drug development, resistive breeding, and transgenic animal breeding. This article introduced the studies about a new bovine antimicrobial peptide-histatherin.

  1. Insect antimicrobial peptides act synergistically to inhibit a trypanosome parasite.

    Science.gov (United States)

    Marxer, Monika; Vollenweider, Vera; Schmid-Hempel, Paul

    2016-05-26

    The innate immune system provides protection from infection by producing essential effector molecules, such as antimicrobial peptides (AMPs) that possess broad-spectrum activity. This is also the case for bumblebees, Bombus terrestris, when infected by the trypanosome, Crithidia bombi Furthermore, the expressed mixture of AMPs varies with host genetic background and infecting parasite strain (genotype). Here, we used the fact that clones of C. bombi can be cultivated and kept as strains in medium to test the effect of various combinations of AMPs on the growth rate of the parasite. In particular, we used pairwise combinations and a range of physiological concentrations of three AMPs, namely Abaecin, Defensin and Hymenoptaecin, synthetized from the respective genomic sequences. We found that these AMPs indeed suppress the growth of eight different strains of C. bombi, and that combinations of AMPs were typically more effective than the use of a single AMP alone. Furthermore, the most effective combinations were rarely those consisting of maximum concentrations. In addition, the AMP combination treatments revealed parasite strain specificity, such that strains varied in their sensitivity towards the same mixtures. Hence, variable expression of AMPs could be an alternative strategy to combat highly variable infections.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160603

  2. Antimicrobial peptide-modified liposomes for bacteria targeted delivery of temoporfin in photodynamic antimicrobial chemotherapy.

    Science.gov (United States)

    Yang, Kewei; Gitter, Burkhard; Rüger, Ronny; Wieland, Gerhard D; Chen, Ming; Liu, Xiangli; Albrecht, Volker; Fahr, Alfred

    2011-10-01

    Photodynamic antimicrobial chemotherapy (PACT) and antimicrobial peptides (AMPs) are two promising strategies to combat the increasing prevalence of antibiotic-resistant bacteria. To take advantage of these two strategies, we integrated a novel antimicrobial peptide (WLBU2) and a potent generation II photosensitizer (temoporfin) into liposomes by preparing WLBU2-modified liposomes, aiming at bacteria targeted delivery of temoporfin for PACT. WLBU2 was successfully coupled to temoporfin-loaded liposomes using a functional phospholipid. The delivery of temoporfin to bacteria was confirmed by fluorescence microscopy and flow cytometry, thus demonstrating that more temoporfin was delivered to bacteria by WLBU2-modified liposomes than by unmodified liposomes. Consequently, the WLBU2-modified liposomes eradicated all methicillin-resistant Staphylococcus aureus (MRSA) and induced a 3.3 log(10) reduction of Pseudomonas aeruginosa in the in vitro photodynamic inactivation test. These findings demonstrate that the use of AMP-modified liposomes is promising for bacteria-targeted delivery of photosensitizers and for improving the PACT efficiency against both gram-positive and gram-negative bacteria in the local infections.

  3. Antimicrobial peptides and proteins in host-microbe interaction and immediate defense

    OpenAIRE

    Kai-Larsen, Ylva

    2009-01-01

    Antimicrobial peptides and proteins (AMPs) are effector molecules of innate immunity and are capable to kill a broad spectrum of microbes, i.e. bacteria, fungi and viruses. They are widespread in nature and have been found in almost all species of the animal kingdom, as well as in plants. The mammalian repertoire of antimicrobial peptides includes the defensins and the cathelicidins. Furthermore, several of the antimicrobial proteins are members of the S100 family. AMPs are ...

  4. A molecular dynamics and circular dichroism study of a novel synthetic antimicrobial peptide

    Science.gov (United States)

    Rodina, N. P.; Yudenko, A. N.; Terterov, I. N.; Eliseev, I. E.

    2013-08-01

    Antimicrobial peptides are a class of small, usually positively charged amphiphilic peptides that are used by the innate immune system to combat bacterial infection in multicellular eukaryotes. Antimicrobial peptides are known for their broad-spectrum antimicrobial activity and thus can be used as a basis for a development of new antibiotics against multidrug-resistant bacteria. The most challengeous task on the way to a therapeutic use of antimicrobial peptides is a rational design of new peptides with enhanced activity and reduced toxicity. Here we report a molecular dynamics and circular dichroism study of a novel synthetic antimicrobial peptide D51. This peptide was earlier designed by Loose et al. using a linguistic model of natural antimicrobial peptides. Molecular dynamics simulation of the peptide folding in explicit solvent shows fast formation of two antiparallel beta strands connected by a beta-turn that is confirmed by circular dichroism measurements. Obtained from simulation amphipatic conformation of the peptide is analysed and possible mechanism of it's interaction with bacterial membranes together with ways to enhance it's antibacterial activity are suggested.

  5. Identification and characterization of a novel antimicrobial peptide from the venom of the ant Tetramorium bicarinatum.

    Science.gov (United States)

    Rifflet, Aline; Gavalda, Sabine; Téné, Nathan; Orivel, Jérôme; Leprince, Jérôme; Guilhaudis, Laure; Génin, Eric; Vétillard, Angélique; Treilhou, Michel

    2012-12-01

    A novel antimicrobial peptide, named Bicarinalin, has been isolated from the venom of the ant Tetramorium bicarinatum. Its amino acid sequence has been determined by de novo sequencing using mass spectrometry and by Edman degradation. Bicarinalin contained 20 amino acid residues and was C-terminally amidated as the majority of antimicrobial peptides isolated to date from insect venoms. Interestingly, this peptide had a linear structure and exhibited no meaningful similarity with any known peptides. Antibacterial activities against Staphylococcus aureus and S. xylosus strains were evaluated using a synthetic replicate. Bicarinalin had a potent and broad antibacterial activity of the same magnitude as Melittin and other hymenopteran antimicrobial peptides such as Pilosulin or Defensin. Moreover, this antimicrobial peptide has a weak hemolytic activity compared to Melittin on erythrocytes, suggesting potential for development into an anti-infective agent for use against emerging antibiotic-resistant pathogens. PMID:22960382

  6. Amphiphilic Peptide Interactions with Complex Biological Membranes : Effect of peptide properties on antimicrobial and anti-inflammatory effects

    OpenAIRE

    Singh, Shalini

    2016-01-01

    With increasing problem of resistance development in bacteria against conventional antibiotics, as well as problems associated with diseases either triggered or enhanced by infection, there is an urgent need to identify new types of effective therapeutics for the treatment of infectious diseases and its consequences. Antimicrobial and anti-inflammatory peptides have attracted considerable interest as potential new antibiotics in this context. While antimicrobial function of such peptides is b...

  7. Temporin-SHf, a New Type of Phe-rich and Hydrophobic Ultrashort Antimicrobial Peptide*

    OpenAIRE

    Abbassi, Feten; Lequin, Olivier; Piesse, Christophe; Goasdoué, Nicole; Foulon, Thierry; Nicolas, Pierre; Ladram, Ali

    2010-01-01

    Because issues of cost and bioavailability have hampered the development of gene-encoded antimicrobial peptides to combat infectious diseases, short linear peptides with high microbial cell selectivity have been recently considered as antibiotic substitutes. A new type of short antimicrobial peptide, designated temporin-SHf, was isolated and cloned from the skin of the frog Pelophylax saharica. Temporin-SHf has a highly hydrophobic sequence (FFFLSRIFa) and possesses the highest percentage of ...

  8. Multivalent display of the antimicrobial peptides BP100 and BP143

    OpenAIRE

    Imma Güell; Rafael Ferre; Kasper K. Sørensen; Esther Badosa; Iteng Ng-Choi; Emilio Montesinos; Eduard Bardají; Lidia Feliu; Jensen, Knud J; Marta Planas

    2012-01-01

    Carbohydrates are considered as promising templates for the display of multiple copies of antimicrobial peptides. Herein, we describe the design and synthesis of chimeric structures containing two or four copies of the antimicrobial peptides KKLFKKILKYL-NH2 (BP100) and KKLfKKILKYL-NH2 (BP143) attached to the carbohydrate template cyclodithioerythritol (cDTE) or α-D-galactopyranoside (Galp). The synthesis involved the preparation of the corresponding peptide aldehyde followed by coupling ...

  9. Effects of antimicrobial peptide revealed by simulations: translocation, pore formation, membrane corrugation and euler buckling.

    Science.gov (United States)

    Chen, Licui; Jia, Nana; Gao, Lianghui; Fang, Weihai; Golubovic, Leonardo

    2013-04-11

    We explore the effects of the peripheral and transmembrane antimicrobial peptides on the lipid bilayer membrane by using the coarse grained Dissipative Particle Dynamics simulations. We study peptide/lipid membrane complexes by considering peptides with various structure, hydrophobicity and peptide/lipid interaction strength. The role of lipid/water interaction is also discussed. We discuss a rich variety of membrane morphological changes induced by peptides, such as pore formation, membrane corrugation and Euler buckling.

  10. Effects of Antimicrobial Peptide Revealed by Simulations: Translocation, Pore Formation, Membrane Corrugation and Euler Buckling

    Directory of Open Access Journals (Sweden)

    Weihai Fang

    2013-04-01

    Full Text Available We explore the effects of the peripheral and transmembrane antimicrobial peptides on the lipid bilayer membrane by using the coarse grained Dissipative Particle Dynamics simulations. We study peptide/lipid membrane complexes by considering peptides with various structure, hydrophobicity and peptide/lipid interaction strength. The role of lipid/water interaction is also discussed. We discuss a rich variety of membrane morphological changes induced by peptides, such as pore formation, membrane corrugation and Euler buckling.

  11. Effects of cationic antimicrobial peptides on liquid-preserved boar spermatozoa.

    Directory of Open Access Journals (Sweden)

    Martin Schulze

    Full Text Available Antibiotics are mandatory additives in semen extenders to control bacterial contamination. The worldwide increase in resistance to conventional antibiotics requires the search for alternatives not only for animal artificial insemination industries, but also for veterinary and human medicine. Cationic antimicrobial peptides are of interest as a novel class of antimicrobial additives for boar semen preservation. The present study investigated effects of two synthetic cyclic hexapeptides (c-WFW, c-WWW and a synthetic helical magainin II amide derivative (MK5E on boar sperm during semen storage at 16 °C for 4 days. The standard extender, Beltsville Thawing Solution (BTS containing 250 µg/mL gentamicin (standard, was compared to combinations of BTS with each of the peptides in a split-sample procedure. Examination revealed peptide- and concentration-dependent effects on sperm integrity and motility. Negative effects were more pronounced for MK5E than in hexapeptide-supplemented samples. The cyclic hexapeptides were partly able to stimulate a linear progressive sperm movement. When using low concentrations of cyclic hexapeptides (4 µM c-WFW, 2 µM c-WWW sperm quality was comparable to the standard extender over the course of preservation. C-WFW-supplemented boar semen resulted in normal fertility rates after AI. In order to investigate the interaction of peptides with the membrane, electron spin resonance spectroscopic measurements were performed using spin-labeled lipids. C-WWW and c-WFW reversibly immobilized an analog of phosphatidylcholine (PC, whereas MK5E caused an irreversible increase of PC mobility. These results suggest testing the antimicrobial efficiency of non-toxic concentrations of selected cyclic hexapeptides as potential candidates to supplement/replace common antibiotics in semen preservation.

  12. Antimicrobial peptides as novel anti-tuberculosis therapeutics.

    Science.gov (United States)

    Silva, João P; Appelberg, Rui; Gama, Francisco Miguel

    2016-01-01

    Tuberculosis (TB), a disease caused by the human pathogen Mycobacterium tuberculosis, has recently joined HIV/AIDS as the world's deadliest infectious disease, affecting around 9.6 million people worldwide in 2014. Of those, about 1.2 million died from the disease. Resistance acquisition to existing antibiotics, with the subsequent emergence of Multi-Drug Resistant mycobacteria strains, together with an increasing economic burden, has urged the development of new anti-TB drugs. In this scope, antimicrobial peptides (AMPs), which are small, cationic and amphipathic peptides that make part of the innate immune system, now arise as promising candidates for TB treatment. In this review, we analyze the potential of AMPs for this application. We address the mechanisms of action, advantages and disadvantages over conventional antibiotics and how problems associated with its use may be overcome to boost their therapeutic potential. Additionally, we address the challenges of translational development from benchside to bedside, evaluate the current development pipeline and analyze the expected global impact from a socio-economic standpoint. The quest for more efficient and more compliant anti-TB drugs, associated with the great therapeutic potential of emerging AMPs and the rising peptide market, provide an optimal environment for the emergence of AMPs as promising therapies. Still, their pharmacological properties need to be enhanced and manufacturing-associated issues need to be addressed. PMID:27235189

  13. Characterization of antimicrobial peptide activity by electrochemical impedance spectroscopy

    Science.gov (United States)

    Chang, William K.; Wimley, William C.; Searson, Peter C.; Hristova, Kalina; Merzlyakov, Mikhail

    2008-01-01

    Summary Electrochemical impedance spectroscopy performed on surface-supported bilayer membranes allows for the monitoring of changes in membrane properties, such as thickness, ion permeability, and homogeneity, after exposure to antimicrobial peptides (AMPs). We show that two model cationic peptides, very similar in sequence but different in activity, induce dramatically different changes in membrane properties as probed by impedance spectroscopy. Moreover, the impedance results excluded the “barrel-stave” and the “toroidal pore” models of AMP mode of action, and are more consistent with the “carpet” and the “detergent” models. The impedance data provide important new insights about the kinetics and the scale of the peptide action which currently are not addressed by the “carpet” and the “detergent” models. The method presented not only provides additional information about the mode of action of a particular AMP, but offers a means of characterizing AMP activity in reproducible, well-defined quantitative terms. PMID:18657512

  14. The Spider Venom Peptide Lycosin-II Has Potent Antimicrobial Activity against Clinically Isolated Bacteria

    Science.gov (United States)

    Wang, Yongjun; Wang, Ling; Yang, Huali; Xiao, Haoliang; Farooq, Athar; Liu, Zhonghua; Hu, Min; Shi, Xiaoliu

    2016-01-01

    Antimicrobial peptides have been accepted as excellent candidates for developing novel antibiotics against drug-resistant bacteria. Recent studies indicate that spider venoms are the source for the identification of novel antimicrobial peptides. In the present study, we isolated and characterized an antibacterial peptide named lycosin-II from the venom of the spider Lycosa singoriensis. It contains 21 amino acid residue lacking cysteine residues and forms a typical linear amphipathic and cationic α-helical conformation. Lycosin-II displays potent bacteriostatic effect on the tested drug-resistant bacterial strains isolated from hospital patients, including multidrug-resistant A. baumannii, which has presented a huge challenge for the infection therapy. The inhibitory ability of lycosin-II might derive from its binding to cell membrane, because Mg2+ could compete with the binding sites to reduce the bacteriostatic potency of lycosin-II. Our data suggest that lycosin-II might be a lead in the development of novel antibiotics for curing drug-resistant bacterial infections. PMID:27128941

  15. The Spider Venom Peptide Lycosin-II Has Potent Antimicrobial Activity against Clinically Isolated Bacteria

    Directory of Open Access Journals (Sweden)

    Yongjun Wang

    2016-04-01

    Full Text Available Antimicrobial peptides have been accepted as excellent candidates for developing novel antibiotics against drug-resistant bacteria. Recent studies indicate that spider venoms are the source for the identification of novel antimicrobial peptides. In the present study, we isolated and characterized an antibacterial peptide named lycosin-II from the venom of the spider Lycosa singoriensis. It contains 21 amino acid residue lacking cysteine residues and forms a typical linear amphipathic and cationic α-helical conformation. Lycosin-II displays potent bacteriostatic effect on the tested drug-resistant bacterial strains isolated from hospital patients, including multidrug-resistant A. baumannii, which has presented a huge challenge for the infection therapy. The inhibitory ability of lycosin-II might derive from its binding to cell membrane, because Mg2+ could compete with the binding sites to reduce the bacteriostatic potency of lycosin-II. Our data suggest that lycosin-II might be a lead in the development of novel antibiotics for curing drug-resistant bacterial infections.

  16. Design and characterization of short antimicrobial peptides using leucine zipper templates with selectivity towards microorganisms.

    Science.gov (United States)

    Ahmad, Aqeel; Azmi, Sarfuddin; Srivastava, Saurabh; Kumar, Amit; Tripathi, Jitendra Kumar; Mishra, Nripendra N; Shukla, Praveen K; Ghosh, Jimut Kanti

    2014-11-01

    Design of antimicrobial peptides with selective activity towards microorganisms is an important step towards the development of new antimicrobial agents. Leucine zipper sequence has been implicated in cytotoxic activity of naturally occurring antimicrobial peptides; moreover, this motif has been utilized for the design of novel antimicrobial peptides with modulated cytotoxicity. To understand further the impact of substitution of amino acids at 'a' and/or 'd' position of a leucine zipper sequence of an antimicrobial peptides on its antimicrobial and cytotoxic properties four short peptides (14-residue) were designed on the basis of a leucine zipper sequence without or with replacement of leucine residues in its 'a' and 'd' positions with D-leucine or alanine or proline residue. The original short leucine zipper peptide (SLZP) and its D-leucine substituted analog, DLSA showed comparable activity against the tested Gram-positive and negative bacteria and the fungal strains. The alanine substituted analog (ASA) though showed appreciable activity against the tested bacteria, it showed to some extent lower activity against the tested fungi. However, the proline substituted analog (PSA) showed lower activity against the tested bacterial or fungal strains. Interestingly, DLSA, ASA and PSA showed significantly lower cytotoxicity than SLZP against both human red blood cells (hRBCs) and murine 3T3 cells. Cytotoxic and bactericidal properties of these peptides matched with peptide-induced damage/permeabilization of mammalian cells and bacteria or their mimetic lipid vesicles suggesting cell membrane could be the target of these peptides. As evidenced by tryptophan fluorescence and acrylamide quenching studies the peptides showed similarities either in interaction or in their localization within the bacterial membrane mimetic negatively charged lipid vesicles. Only SLZP showed localization inside the mammalian membrane mimetic zwitterionic lipid vesicles. The results show

  17. Decreased outer membrane permeability protects mycobacteria from killing by ubiquitin-derived peptides.

    Science.gov (United States)

    Purdy, Georgiana E; Niederweis, Michael; Russell, David G

    2009-09-01

    Ubiquitin-derived peptides are bactericidal in vitro and contribute to the mycobactericidal activity of the lysosome. To further define interactions of ubiquitin-derived peptides with mycobacteria, we screened for mutants with increased resistance to the bactericidal activity of the synthetic ubiquitin-derived peptide Ub2. The four Ub2-resistant Mycobacterium smegmatis mutants were also resistant to the bactericidal action of other antimicrobial peptides and macrophages. Two mutants were in the mspA gene encoding the main M. smegmatis porin. Using a translocation-deficient MspA point mutant, we showed that susceptibility of M. smegmatis to Ub2 was independent of MspA channel activity. Instead, the M. smegmatis Ub2-resistant mutants shared a common phenotype of decreased cell wall permeability compared with wild-type bacteria. Expression of mspA rendered Mycobacterium tuberculosis CDC1551 more susceptible both to ubiquitin-derived peptides in vitro and to lysosomal killing in macrophages. Finally, biochemical assays designed to assess membrane integrity indicated that Ub2 treatment impairs membrane function of M. smegmatis and M. tuberculosis cells. The M. smegmatis Ub2-resistant mutants were more resistant than wild-type M. smegmatis to this damage. We conclude that Ub2 targets mycobacterial membranes and that reduced membrane permeability provides mycobacteria intrinsic resistance against antimicrobial compounds including bactericidal ubiquitin-derived peptides. PMID:19682257

  18. Effect of Antimicrobial Peptide-Amide: Indolicidin on Biological Membranes

    Directory of Open Access Journals (Sweden)

    Attila Gergely Végh

    2011-01-01

    Full Text Available Indolicidin, a cationic antimicrobial tridecapeptide amide, is rich in proline and tryptophan residues. Its biological activity is intensively studied, but the details how indolicidin interacts with membranes are not fully understood yet. We report here an in situ atomic force microscopic study describing the effect of indolicidin on an artificial supported planar bilayer membrane of dipalmitoyl phosphatidylcholine (DPPC and on purple membrane of Halobacterium salinarum. Concentration dependent interaction of the peptide and membranes was found in case of DPPC resulting the destruction of the membrane. Purple membrane was much more resistant against indolicidin, probably due to its high protein content. Indolicidin preferred the border of membrane disks, where the lipids are more accessible. These data suggest that the atomic force microscope is a powerful tool in the study of indolicidin-membrane interaction.

  19. Antimicrobial peptide (Cn-AMP2) from liquid endosperm of Cocos nucifera forms amyloid-like fibrillar structure.

    Science.gov (United States)

    Gour, Shalini; Kaushik, Vibha; Kumar, Vijay; Bhat, Priyanka; Yadav, Subhash C; Yadav, Jay K

    2016-04-01

    Cn-AMP2 is an antimicrobial peptide derived from liquid endosperm of coconut (Cocos nucifera). It consists of 11 amino acid residues and predicted to have high propensity for β-sheet formation that disposes this peptide to be amyloidogenic. In the present study, we have examined the amyloidogenic propensities of Cn-AMP2 in silico and then tested the predictions under in vitro conditions. The in silico study revealed that the peptide possesses high amyloidogenic propensity comparable with Aβ. Upon solubilisation and agitation in aqueous buffer, Cn-AMP2 forms visible aggregates that display bathochromic shift in the Congo red absorbance spectra, strong increase in thioflavin T fluorescence and fibrillar morphology under transmission electron microscopy. All these properties are typical of an amyloid fibril derived from various proteins/peptides including Aβ. PMID:27028204

  20. Selection on an antimicrobial peptide defensin in ants.

    Science.gov (United States)

    Viljakainen, Lumi; Pamilo, Pekka

    2008-12-01

    Ants live in crowded nests with interacting individuals, which makes them particularly prone to infectious diseases. The question is, how do ants cope with the increased risk of pathogen transmission due to sociality? We have studied the molecular evolution of defensin, a gene encoding an antimicrobial protein, in ants. Defensin sequences from several ant species were analyzed with maximum likelihood models of codon substitution to infer selection. Positive selection was detected in the mature region of defensin, whereas the signal and pro regions seem to be evolving neutrally. We also found a significantly higher rate of nonsynonymous substitutions in some phylogenetic lineages, as well as dN/dS >1, suggesting varying selection pressures in different lineages. Earlier studies on the molecular evolution of insect antimicrobial peptide genes have focused on termites and dipteran species, and detected positive selection only in duplicated termicin genes in termites. These findings, together with our present results, provide an indication that the immune systems of social insects (ants and termites) and dipteran insects may have responded differently to the selection pressure caused by microbial pathogens. PMID:18956133

  1. Label-free detection of biomolecular interaction — DNA — Antimicrobial peptide binding

    DEFF Research Database (Denmark)

    Fojan, Peter; Jensen, Kasper Risgaard; Gurevich, Leonid

    2011-01-01

    of plasmon based biosensors to the study of the interaction of Antimicrobial peptide IL4 and DNA. Our results indicate high affinity binding between IL4 and DNA thereby preventing DNA replication and eventually killing the affected cell. We speculate that this is common for a large class of Antimicrobial...... an interest in Antimicrobial peptides that are active against broad range of infections including bacteria, fungi and viruses and were shown to be capable of treating multi-resistant infection either alone or in combination with the conventional antibiotics. In this paper , we demonstrate an application...... peptides and can be a key point explaining their broad range of activity against various pathogens....

  2. Cateslytin, a chromogranin A derived peptide is active against Staphylococcus aureus and resistant to degradation by its proteases.

    Directory of Open Access Journals (Sweden)

    Rizwan Aslam

    Full Text Available Innate immunity involving antimicrobial peptides represents an integrated and highly effective system of molecular and cellular mechanisms that protects host against infections. One of the most frequent hospital-acquired pathogens, Staphylococcus aureus, capable of producing proteolytic enzymes, which can degrade the host defence agents and tissue components. Numerous antimicrobial peptides derived from chromogranins, are secreted by nervous, endocrine and immune cells during stress conditions. These kill microorganisms by their lytic effect at micromolar range, using a pore-forming mechanism against Gram-positive bacteria, filamentous fungi and yeasts. In this study, we tested antimicrobial activity of chromogranin A-derived peptides (catestatin and cateslytin against S. aureus and analysed S. aureus-mediated proteolysis of these peptides using HPLC, sequencing and MALDI-TOF mass spectrometry. Interestingly, this study is the first to demonstrate that cateslytin, the active domain of catestatin, is active against S. aureus and is interestingly resistant to degradation by S. aureus proteases.

  3. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Rafi eRashid

    2016-06-01

    Full Text Available Antimicrobial peptides (AMPs are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs target anionic lipids (e.g. phosphatidylglycerol (PG and cardiolipins (CL in the cell membrane and anionic components (e.g. lipopolysaccharide (LPS and lipoteichoic acid (LTA of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g. lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1 CAMP disruption mechanisms, (2 delocalization of membrane proteins and lipids by CAMPs, and (3 CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging and non-detergent-based membrane domain extraction.

  4. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides.

    Science.gov (United States)

    Rashid, Rafi; Veleba, Mark; Kline, Kimberly A

    2016-01-01

    Antimicrobial peptides (AMPs) are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs) target anionic lipids [e.g., phosphatidylglycerol (PG) and cardiolipins (CL)] in the cell membrane and anionic components [e.g., lipopolysaccharide (LPS) and lipoteichoic acid (LTA)] of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g., lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1) CAMP disruption mechanisms, (2) delocalization of membrane proteins and lipids by CAMPs, and (3) CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging, and non-detergent-based membrane domain extraction. PMID:27376064

  5. Intestinal antimicrobial peptides during homeostasis, infection and disease

    Directory of Open Access Journals (Sweden)

    Luciana R Muniz

    2012-10-01

    Full Text Available Antimicrobial peptides (AMPs, including defensins and cathelicidins, constitute an arsenal of innate regulators of paramount importance in the gut. The intestinal epithelium is exposed to myriad of enteric pathogens and these endogenous peptides are essential to fend off microbes and protect against infections. It is becoming increasingly evident that AMPs shape the composition of the commensal microbiota and help maintain intestinal homeostasis. They contribute to innate immunity, hence playing important functions in health and disease. AMP expression is tightly controlled by the engagement of pattern recognition receptors (PRRs and their impairment is linked to abnormal host responses to infection and inflammatory bowel diseases (IBD. In this review, we provide an overview of the mucosal immune barriers and the intricate crosstalk between the host and the microbiota during homeostasis. We focus on the AMPs and pay particular attention to how PRRs promote their secretion in the intestine. Furthermore, we discuss their production and main functions in three different scenarios, at steady state, throughout infection with enteric pathogens and IBD.

  6. Antimicrobial peptide exposure selects for Staphylococcus aureus resistance to human defence peptides

    DEFF Research Database (Denmark)

    Kubicek-Sutherland, Jessica Z.; Lofton, Hava; Vestergaard, Martin;

    2016-01-01

    Background: The clinical development of antimicrobial peptides (AMPs) is currently under evaluation to combat the rapid increase in MDR bacterial pathogens. However, many AMPs closely resemble components of the human innate immune system and the ramifications of prolonged bacterial exposure to AMPs...... suggest that therapeutic use of AMPs could select for virulent mutants with crossresistance to human innate immunity as well as antibiotic therapy. Thus, therapeutic use of AMPs and the implications of cross-resistance need to be carefully monitored and evaluated....... of sepsis. Results: AMP-resistant Staphylococcus aureus mutants often displayed little to no fitness cost and caused invasive disease in mice. Further, this phenotype coincided with diminished susceptibility to both clinically prescribed antibiotics and human defence peptides. Conclusions: These findings...

  7. Antimicrobial effects of GL13K peptide coatings on S. mutans and L. casei

    Science.gov (United States)

    Schnitt, Rebecca Ann

    Background: Enamel breakdown around orthodontic brackets, so-called "white spot lesions", is the most common complication of orthodontic treatment. White spot lesions are caused by bacteria such as Streptococci and Lactobacilli, whose acidic byproducts cause demineralization of enamel crystals. Aims: The aim of this project was to develop an antimicrobial peptide coating for titanium alloy that is capable of killing acidogenic bacteria, specifically Streptococcus mutans and Lactobacillus casei. The long-term goal is to create an antimicrobial-coated orthodontic bracket with the ability to reduce or prevent the formation of white spot lesions in orthodontic patients thereby improving clinical outcomes. Methods: First, an alkaline etching method with NaOH was established to allow effective coating of titanium discs with GL13K, an antimicrobial peptide derived from human saliva. Coatings were verified by contact angle measures, and treated discs were characterized using scanning electron microscopy. Secondly, GL13K coatings were tested against hydrolytic, proteolytic and mechanical challenges to ensure robust coatings. Third, a series of qualitative and quantitative microbiology experiments were performed to determine the effects of GL13K--L and GL13K--D on S. mutans and L. casei, both in solution and coated on titanium. Results: GL13K-coated discs were stable after two weeks of challenges. GL13K--D was effective at killing S. mutans in vitro at low doses. GL13K--D also demonstrated a bactericidal effect on L. casei, however, in contrast to S. mutans, the effect on L. casei was not statistically significant. Conclusion: GL13K--D is a promising candidate for antimicrobial therapy with possible applications for prevention of white spot lesions in orthodontics.

  8. The pseudokinase NIPI-4 is a novel regulator of antimicrobial peptide gene expression.

    Directory of Open Access Journals (Sweden)

    Sid Ahmed Labed

    Full Text Available Hosts have developed diverse mechanisms to counter the pathogens they face in their natural environment. Throughout the plant and animal kingdoms, the up-regulation of antimicrobial peptides is a common response to infection. In C. elegans, infection with the natural pathogen Drechmeria coniospora leads to rapid induction of antimicrobial peptide gene expression in the epidermis. Through a large genetic screen we have isolated many new mutants that are incapable of upregulating the antimicrobial peptide nlp-29 in response to infection (i.e. with a Nipi or 'no induction of peptide after infection' phenotype. More than half of the newly isolated Nipi mutants do not correspond to genes previously associated with the regulation of antimicrobial peptides. One of these, nipi-4, encodes a member of a nematode-specific kinase family. NIPI-4 is predicted to be catalytically inactive, thus to be a pseudokinase. It acts in the epidermis downstream of the PKC∂ TPA-1, as a positive regulator of nlp antimicrobial peptide gene expression after infection. It also controls the constitutive expression of antimicrobial peptide genes of the cnc family that are targets of TGFß regulation. Our results open the way for a more detailed understanding of how host defense pathways can be molded by environmental pathogens.

  9. Antimicrobial Peptides and Innate Lung Defenses: Role in Infectious and Noninfectious Lung Diseases and Therapeutic Applications.

    Science.gov (United States)

    Hiemstra, Pieter S; Amatngalim, Gimano D; van der Does, Anne M; Taube, Christian

    2016-02-01

    Respiratory infections are a major clinical problem, and treatment is increasingly complicated by the emergence of microbial antibiotic resistance. Development of new antibiotics is notoriously costly and slow; therefore, alternative strategies are needed. Antimicrobial peptides, central effector molecules of the immune system, are being considered as alternatives to conventional antibiotics. These peptides display a range of activities, including not only direct antimicrobial activity, but also immunomodulation and wound repair. In the lung, airway epithelial cells and neutrophils in particular contribute to their synthesis. The relevance of antimicrobial peptides for host defense against infection has been demonstrated in animal models and is supported by observations in patient studies, showing altered expression and/or unfavorable circumstances for their action in a variety of lung diseases. Importantly, antimicrobial peptides are active against microorganisms that are resistant against conventional antibiotics, including multidrug-resistant bacteria. Several strategies have been proposed to use these peptides in the treatment of infections, including direct administration of antimicrobial peptides, enhancement of their local production, and creation of more favorable circumstances for their action. In this review, recent developments in antimicrobial peptides research in the lung and clinical applications for novel therapies of lung diseases are discussed.

  10. Quantitative Studies of Antimicrobial Peptide Pore Formation in Large Unilamellar Vesicles by Fluorescence Correlation Spectroscopy (FCS)

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2013-01-01

    leakage of fluorescent probes of different sizes through transmembrane pores formed by each of the three representative antimicrobial peptides: melittin, magainin 2, and mastoparan X. The experimental results demonstrate that leakage assays based on fluorescence correlation spectroscopy offer new and...

  11. Antimicrobial Peptide-Driven Colloidal Transformations in Liquid-Crystalline Nanocarriers

    DEFF Research Database (Denmark)

    Gontsarik, Mark; Buhmann, Matthias T; Yaghmur, Anan;

    2016-01-01

    Designing efficient colloidal systems for the delivery of membrane active antimicrobial peptides requires in-depth understanding of their structural and morphological characteristics. Using dispersions of inverted type bicontinuous cubic phase (cubosomes), we examine the effect of integrating the...

  12. Using antimicrobial host defense peptides as anti-infective and immunomodulatory agents.

    Science.gov (United States)

    Kruse, Thomas; Kristensen, Hans-Henrik

    2008-12-01

    Virtually all life forms express short antimicrobial cationic peptides as an important component of their innate immune defenses. They serve as endogenous antibiotics that are able to rapidly kill an unusually broad range of bacteria, fungi and viruses. Consequently, considerable efforts have been expended to exploit the therapeutic potential of these antimicrobial peptides. Within the last couple of years, it has become increasingly clear that many of these peptides, in addition to their direct antimicrobial activity, also have a wide range of functions in modulating both innate and adaptive immunity. For one class of antimicrobial peptides, such as the human defensins, their primary role may even be as immunomodulators. These properties potentially provide entirely new therapeutic approaches to anti-infective therapy.

  13. Molecular genetic analysis of a locus required for resistance to antimicrobial peptides in Salmonella typhimurium.

    OpenAIRE

    Parra-Lopez, C; Baer, M. T.; Groisman, E A

    1993-01-01

    The innate immunity of vertebrates and invertebrates to microbial infection is mediated in part by small cationic peptides with antimicrobial activity. Successful pathogens have evolved mechanisms to withstand the antibiotic activity of these molecules. We have isolated a set of genes from Salmonella typhimurium which are required for virulence and resistance to the antimicrobial peptides melittin and protamine. Sequence analysis of a 5.7 kb segment from the wild-type plasmid conferring resis...

  14. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice

    OpenAIRE

    SHI, Wei; Li, Caiyun; Li, Man; Zong, Xicui; Han, Dongju; Chen, Yuqing

    2016-01-01

    Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metab...

  15. Production of phytotoxic cationic α-helical antimicrobial peptides in plant cells using inducible promoters.

    Directory of Open Access Journals (Sweden)

    Nuri Company

    Full Text Available Synthetic linear antimicrobial peptides with cationic α-helical structures, such as BP100, have potent and specific activities against economically important plant pathogenic bacteria. They are also recognized as valuable therapeutics and preservatives. However, highly active BP100 derivatives are often phytotoxic when expressed at high levels as recombinant peptides in plants. Here we demonstrate that production of recombinant phytotoxic peptides in transgenic plants is possible by strictly limiting transgene expression to certain tissues and conditions, and specifically that minimization of this expression during transformation and regeneration of transgenic plants is essential to obtain viable plant biofactories. On the basis of whole-genome transcriptomic data available online, we identified the Os.hsp82 promoter that fulfilled this requirement and was highly induced in response to heat shock. Using this strategy, we generated transgenic rice lines producing moderate yields of severely phytotoxic BP100 derivatives on exposure to high temperature. In addition, a threshold for gene expression in selected tissues and stages was experimentally established, below which the corresponding promoters should be suitable for driving the expression of recombinant phytotoxic proteins in genetically modified plants. In view of the growing transcriptomics data available, this approach is of interest to assist promoter selection for specific purposes.

  16. Antimicrobial Peptides as Potential Alternatives to Antibiotics in Food Animal Industry

    OpenAIRE

    Shuai Wang; Xiangfang Zeng; Qing Yang; Shiyan Qiao

    2016-01-01

    Over the last decade, the rapid emergence of multidrug-resistant pathogens has become a global concern, which has prompted the search for alternative antibacterial agents for use in food animals. Antimicrobial peptides (AMPs), produced by bacteria, insects, amphibians and mammals, as well as by chemical synthesis, are possible candidates for the design of new antimicrobial agents because of their natural antimicrobial properties and a low propensity for development of resistance by microorgan...

  17. Effect of the antimicrobial peptide tritrpticin on the in vitro viability and growth of Trichomonas vaginalis.

    Science.gov (United States)

    Infante, Veronica V; Miranda-Olvera, Alma D; De Leon-Rodriguez, Luis M; Anaya-Velazquez, Fernando; Rodriguez, Mayra C; Avila, Eva E

    2011-01-01

    Antimicrobial peptides are widely distributed in nature; they play important roles in several aspects of innate immunity and may provide a basis for the design of novel therapeutic agents. In this study, C-amidated tritrpticin, a 13 amino acid tryptophan-rich antimicrobial peptide derived from a porcine cathelicidin, was tested against Trichomonas vaginalis, a protozoan that causes a serious non-viral sexually transmitted disease associated with preterm birth, low birth weight, and high risk of HIV-1 infection. Tritrpticin was selected due to its reasonably easy synthesis and because analogs with lower toxicity may be designed. Our results show that tritrpticin-NH(2) at either 100 or 200 μg/ml (52.5 or 105 μM) clearly reduces the viability and growth of Trichomonas vaginalis. Together with tritrpticin-NH(2), sodium bicarbonate further limited trichomonad growth. Additionally, a low concentration of metronidazole (5.8 μM), the most commonly used medication for Trichomonas vaginalis, was more effective against the growth of the parasite when it was combined with tritrpticin-NH(2).

  18. Design of embedded-hybrid antimicrobial peptides with enhanced cell selectivity and anti-biofilm activity.

    Directory of Open Access Journals (Sweden)

    Wei Xu

    Full Text Available Antimicrobial peptides have attracted considerable attention because of their broad-spectrum antimicrobial activity and their low prognostic to induce antibiotic resistance which is the most common source of failure in bacterial infection treatment along with biofilms. The method to design hybrid peptide integrating different functional domains of peptides has many advantages. In this study, we designed an embedded-hybrid peptide R-FV-I16 by replacing a functional defective sequence RR7 with the anti-biofilm sequence FV7 embedded in the middle position of peptide RI16. The results demonstrated that the synthetic hybrid the peptide R-FV-I16 had potent antimicrobial activity over a wide range of Gram-negative and Gram-positive bacteria, as well as anti-biofilm activity. More importantly, R-FV-I16 showed lower hemolytic activity and cytotoxicity. Fluorescent assays demonstrated that R-FV-I16 depolarized the outer and the inner bacterial membranes, while scanning electron microscopy and transmission electron microscopy further indicated that this peptide killed bacterial cells by disrupting the cell membrane, thereby damaging membrane integrity. Results from SEM also provided evidence that R-FV-I16 inherited anti-biofilm activity from the functional peptide sequence FV7. Embedded-hybrid peptides could provide a new pattern for combining different functional domains and showing an effective avenue to screen for novel antimicrobial agents.

  19. De Novo Transcriptome Analysis and Detection of Antimicrobial Peptides of the American Cockroach Periplaneta americana (Linnaeus.

    Directory of Open Access Journals (Sweden)

    In-Woo Kim

    Full Text Available Cockroaches are surrogate hosts for microbes that cause many human diseases. In spite of their generally destructive nature, cockroaches have recently been found to harbor potentially beneficial and medically useful substances such as drugs and allergens. However, genomic information for the American cockroach (Periplaneta americana is currently unavailable; therefore, transcriptome and gene expression profiling is needed as an important resource to better understand the fundamental biological mechanisms of this species, which would be particularly useful for the selection of novel antimicrobial peptides. Thus, we performed de novo transcriptome analysis of P. americana that were or were not immunized with Escherichia coli. Using an Illumina HiSeq sequencer, we generated a total of 9.5 Gb of sequences, which were assembled into 85,984 contigs and functionally annotated using Basic Local Alignment Search Tool (BLAST, Gene Ontology (GO, and Kyoto Encyclopedia of Genes and Genomes (KEGG database terms. Finally, using an in silico antimicrobial peptide prediction method, 86 antimicrobial peptide candidates were predicted from the transcriptome, and 21 of these peptides were experimentally validated for their antimicrobial activity against yeast and gram positive and -negative bacteria by a radial diffusion assay. Notably, 11 peptides showed strong antimicrobial activities against these organisms and displayed little or no cytotoxic effects in the hemolysis and cell viability assay. This work provides prerequisite baseline data for the identification and development of novel antimicrobial peptides, which is expected to provide a better understanding of the phenomenon of innate immunity in similar species.

  20. De Novo Transcriptome Analysis and Detection of Antimicrobial Peptides of the American Cockroach Periplaneta americana (Linnaeus).

    Science.gov (United States)

    Kim, In-Woo; Lee, Joon Ha; Subramaniyam, Sathiyamoorthy; Yun, Eun-Young; Kim, Iksoo; Park, Junhyung; Hwang, Jae Sam

    2016-01-01

    Cockroaches are surrogate hosts for microbes that cause many human diseases. In spite of their generally destructive nature, cockroaches have recently been found to harbor potentially beneficial and medically useful substances such as drugs and allergens. However, genomic information for the American cockroach (Periplaneta americana) is currently unavailable; therefore, transcriptome and gene expression profiling is needed as an important resource to better understand the fundamental biological mechanisms of this species, which would be particularly useful for the selection of novel antimicrobial peptides. Thus, we performed de novo transcriptome analysis of P. americana that were or were not immunized with Escherichia coli. Using an Illumina HiSeq sequencer, we generated a total of 9.5 Gb of sequences, which were assembled into 85,984 contigs and functionally annotated using Basic Local Alignment Search Tool (BLAST), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) database terms. Finally, using an in silico antimicrobial peptide prediction method, 86 antimicrobial peptide candidates were predicted from the transcriptome, and 21 of these peptides were experimentally validated for their antimicrobial activity against yeast and gram positive and -negative bacteria by a radial diffusion assay. Notably, 11 peptides showed strong antimicrobial activities against these organisms and displayed little or no cytotoxic effects in the hemolysis and cell viability assay. This work provides prerequisite baseline data for the identification and development of novel antimicrobial peptides, which is expected to provide a better understanding of the phenomenon of innate immunity in similar species. PMID:27167617

  1. De Novo Transcriptome Analysis and Detection of Antimicrobial Peptides of the American Cockroach Periplaneta americana (Linnaeus).

    Science.gov (United States)

    Kim, In-Woo; Lee, Joon Ha; Subramaniyam, Sathiyamoorthy; Yun, Eun-Young; Kim, Iksoo; Park, Junhyung; Hwang, Jae Sam

    2016-01-01

    Cockroaches are surrogate hosts for microbes that cause many human diseases. In spite of their generally destructive nature, cockroaches have recently been found to harbor potentially beneficial and medically useful substances such as drugs and allergens. However, genomic information for the American cockroach (Periplaneta americana) is currently unavailable; therefore, transcriptome and gene expression profiling is needed as an important resource to better understand the fundamental biological mechanisms of this species, which would be particularly useful for the selection of novel antimicrobial peptides. Thus, we performed de novo transcriptome analysis of P. americana that were or were not immunized with Escherichia coli. Using an Illumina HiSeq sequencer, we generated a total of 9.5 Gb of sequences, which were assembled into 85,984 contigs and functionally annotated using Basic Local Alignment Search Tool (BLAST), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) database terms. Finally, using an in silico antimicrobial peptide prediction method, 86 antimicrobial peptide candidates were predicted from the transcriptome, and 21 of these peptides were experimentally validated for their antimicrobial activity against yeast and gram positive and -negative bacteria by a radial diffusion assay. Notably, 11 peptides showed strong antimicrobial activities against these organisms and displayed little or no cytotoxic effects in the hemolysis and cell viability assay. This work provides prerequisite baseline data for the identification and development of novel antimicrobial peptides, which is expected to provide a better understanding of the phenomenon of innate immunity in similar species.

  2. Self-assembly of cationic multidomain peptide hydrogels: supramolecular nanostructure and rheological properties dictate antimicrobial activity.

    Science.gov (United States)

    Jiang, Linhai; Xu, Dawei; Sellati, Timothy J; Dong, He

    2015-12-01

    Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications.

  3. Simultaneous Antibiofilm and Antiviral Activities of an Engineered Antimicrobial Peptide during Virus-Bacterium Coinfection

    Science.gov (United States)

    Melvin, Jeffrey A.; Lashua, Lauren P.; Kiedrowski, Megan R.; Yang, Guanyi; Deslouches, Berthony; Montelaro, Ronald C.

    2016-01-01

    ABSTRACT Antimicrobial-resistant infections are an urgent public health threat, and development of novel antimicrobial therapies has been painstakingly slow. Polymicrobial infections are increasingly recognized as a significant source of severe disease and also contribute to reduced susceptibility to antimicrobials. Chronic infections also are characterized by their ability to resist clearance, which is commonly linked to the development of biofilms that are notorious for antimicrobial resistance. The use of engineered cationic antimicrobial peptides (eCAPs) is attractive due to the slow development of resistance to these fast-acting antimicrobials and their ability to kill multidrug-resistant clinical isolates, key elements for the success of novel antimicrobial agents. Here, we tested the ability of an eCAP, WLBU2, to disrupt recalcitrant Pseudomonas aeruginosa biofilms. WLBU2 was capable of significantly reducing biomass and viability of P. aeruginosa biofilms formed on airway epithelium and maintained activity during viral coinfection, a condition that confers extraordinary levels of antibiotic resistance. Biofilm disruption was achieved in short treatment times by permeabilization of bacterial membranes. Additionally, we observed simultaneous reduction of infectivity of the viral pathogen respiratory syncytial virus (RSV). WLBU2 is notable for its ability to maintain activity across a broad range of physiological conditions and showed negligible toxicity toward the airway epithelium, expanding its potential applications as an antimicrobial therapeutic. IMPORTANCE Antimicrobial-resistant infections are an urgent public health threat, making development of novel antimicrobials able to effectively treat these infections extremely important. Chronic and polymicrobial infections further complicate antimicrobial therapy, often through the development of microbial biofilms. Here, we describe the ability of an engineered antimicrobial peptide to disrupt biofilms

  4. Simultaneous Antibiofilm and Antiviral Activities of an Engineered Antimicrobial Peptide during Virus-Bacterium Coinfection.

    Science.gov (United States)

    Melvin, Jeffrey A; Lashua, Lauren P; Kiedrowski, Megan R; Yang, Guanyi; Deslouches, Berthony; Montelaro, Ronald C; Bomberger, Jennifer M

    2016-01-01

    Antimicrobial-resistant infections are an urgent public health threat, and development of novel antimicrobial therapies has been painstakingly slow. Polymicrobial infections are increasingly recognized as a significant source of severe disease and also contribute to reduced susceptibility to antimicrobials. Chronic infections also are characterized by their ability to resist clearance, which is commonly linked to the development of biofilms that are notorious for antimicrobial resistance. The use of engineered cationic antimicrobial peptides (eCAPs) is attractive due to the slow development of resistance to these fast-acting antimicrobials and their ability to kill multidrug-resistant clinical isolates, key elements for the success of novel antimicrobial agents. Here, we tested the ability of an eCAP, WLBU2, to disrupt recalcitrant Pseudomonas aeruginosa biofilms. WLBU2 was capable of significantly reducing biomass and viability of P. aeruginosa biofilms formed on airway epithelium and maintained activity during viral coinfection, a condition that confers extraordinary levels of antibiotic resistance. Biofilm disruption was achieved in short treatment times by permeabilization of bacterial membranes. Additionally, we observed simultaneous reduction of infectivity of the viral pathogen respiratory syncytial virus (RSV). WLBU2 is notable for its ability to maintain activity across a broad range of physiological conditions and showed negligible toxicity toward the airway epithelium, expanding its potential applications as an antimicrobial therapeutic. IMPORTANCE Antimicrobial-resistant infections are an urgent public health threat, making development of novel antimicrobials able to effectively treat these infections extremely important. Chronic and polymicrobial infections further complicate antimicrobial therapy, often through the development of microbial biofilms. Here, we describe the ability of an engineered antimicrobial peptide to disrupt biofilms formed by the

  5. Potential Use of Antimicrobial Peptides as Vaginal Spermicides/Microbicides.

    Science.gov (United States)

    Tanphaichitr, Nongnuj; Srakaew, Nopparat; Alonzi, Rhea; Kiattiburut, Wongsakorn; Kongmanas, Kessiri; Zhi, Ruina; Li, Weihua; Baker, Mark; Wang, Guanshun; Hickling, Duane

    2016-01-01

    The concurrent increases in global population and sexually transmitted infection (STI) demand a search for agents with dual spermicidal and microbicidal properties for topical vaginal application. Previous attempts to develop the surfactant spermicide, nonoxynol-9 (N-9), into a vaginal microbicide were unsuccessful largely due to its inefficiency to kill microbes. Furthermore, N-9 causes damage to the vaginal epithelium, thus accelerating microbes to enter the women's body. For this reason, antimicrobial peptides (AMPs), naturally secreted by all forms of life as part of innate immunity, deserve evaluation for their potential spermicidal effects. To date, twelve spermicidal AMPs have been described including LL-37, magainin 2 and nisin A. Human cathelicidin LL-37 is the most promising spermicidal AMP to be further developed for vaginal use for the following reasons. First, it is a human AMP naturally produced in the vagina after intercourse. Second, LL-37 exerts microbicidal effects to numerous microbes including those that cause STI. Third, its cytotoxicity is selective to sperm and not to the female reproductive tract. Furthermore, the spermicidal effects of LL-37 have been demonstrated in vivo in mice. Therefore, the availability of LL-37 as a vaginal spermicide/microbicide will empower women for self-protection against unwanted pregnancies and STI. PMID:26978373

  6. The Antimicrobial Peptide Lysozyme Is Induced after Multiple Trauma

    Directory of Open Access Journals (Sweden)

    Tim Klüter

    2014-01-01

    Full Text Available The antimicrobial peptide lysozyme is an important factor of innate immunity and exerts high potential of antibacterial activity. In the present study we evaluated the lysozyme expression in serum of multiple injured patients and subsequently analyzed their possible sources and signaling pathways. Expression of lysozyme was examined in blood samples of multiple trauma patients from the day of trauma until 14 days after trauma by ELISA. To investigate major sources of lysozyme, its expression and regulation in serum samples, different blood cells, and tissue samples were analysed by ELISA and real-time PCR. Neutrophils and hepatocytes were stimulated with cytokines and supernatant of Staphylococcus aureus. The present study demonstrates the induction and release of lysozyme in serum of multiple injured patients. The highest lysozyme expression of all tested cells and tissues was detected in neutrophils. Stimulation with trauma-related factors such as interleukin-6 and S. aureus induced lysozyme expression. Liver tissue samples of patients without trauma show little lysozyme expression compared to neutrophils. After stimulation with bacterial fragments, lysozyme expression of hepatocytes is upregulated significantly. Toll-like receptor 2, a classic receptor of Gram-positive bacterial protein, was detected as a possible target for lysozyme induction.

  7. Potential Use of Antimicrobial Peptides as Vaginal Spermicides/Microbicides

    Directory of Open Access Journals (Sweden)

    Nongnuj Tanphaichitr

    2016-03-01

    Full Text Available The concurrent increases in global population and sexually transmitted infection (STI demand a search for agents with dual spermicidal and microbicidal properties for topical vaginal application. Previous attempts to develop the surfactant spermicide, nonoxynol-9 (N-9, into a vaginal microbicide were unsuccessful largely due to its inefficiency to kill microbes. Furthermore, N-9 causes damage to the vaginal epithelium, thus accelerating microbes to enter the women’s body. For this reason, antimicrobial peptides (AMPs, naturally secreted by all forms of life as part of innate immunity, deserve evaluation for their potential spermicidal effects. To date, twelve spermicidal AMPs have been described including LL-37, magainin 2 and nisin A. Human cathelicidin LL-37 is the most promising spermicidal AMP to be further developed for vaginal use for the following reasons. First, it is a human AMP naturally produced in the vagina after intercourse. Second, LL-37 exerts microbicidal effects to numerous microbes including those that cause STI. Third, its cytotoxicity is selective to sperm and not to the female reproductive tract. Furthermore, the spermicidal effects of LL-37 have been demonstrated in vivo in mice. Therefore, the availability of LL-37 as a vaginal spermicide/microbicide will empower women for self-protection against unwanted pregnancies and STI.

  8. Biotic stress resistance in agriculture through antimicrobial peptides.

    Science.gov (United States)

    Sarika; Iquebal, M A; Rai, Anil

    2012-08-01

    Antimicrobial peptides (AMPs) are the hosts' defense molecules against microbial pathogens and gaining extensive research attention worldwide. These have been reported to play vital role of host innate immunity in response to microbial challenges. AMPs can be used as a natural antibiotic as an alternative of their chemical counterpart for protection of plants/animals against diseases. There are a number of sources of AMPs including prokaryotic and eukaryotic organisms and are present, both in vertebrates and invertebrates. AMPs can be classified as cationic or anionic, based on net charges. Large number of databases and tools are available in the public domain which can be used for development of new genetically modified disease resistant varieties/breeds for agricultural production. The results of the biotechnological research as well as genetic engineering related to AMPs have shown high potential for reduction of economic losses of agricultural produce due to pathogens. In this article, an attempt has been made to introduce the role of AMPs in relation to plants and animals. Their functional and structural characteristics have been described in terms of its role in agriculture. Different sources of AMPs and importance of these sources has been reviewed in terms of its availability. This article also reviews the bioinformatics resources including different database tools and algorithms available in public domain. References of promising biotechnology research in relation to AMPs, prospects of AMPs for further development of genetically modified varieties/breeds are highlighted. AMPs are valuable resource for students, researchers, educators and medical and industrial personnel.

  9. Molecular dynamics simulations of helical antimicrobial peptides in SDS micelles: what do point mutations achieve?

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Kaznessis, Yiannis N

    2005-01-01

    illuminate the structural and binding properties of the mutant peptides which make them less toxic compared to ovispirin. Based on previous data and the current simulations, we propose that introduction of a bend/hinge at the center of helical antimicrobial peptides (containing a specific C-terminal motif...

  10. Side Chain Hydrophobicity Modulates Therapeutic Activity and Membrane Selectivity of Antimicrobial Peptide Mastoparan-X

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Etzerodt, Thomas Povl; Gjetting, Torben;

    2014-01-01

    The discovery of new anti-infective compounds is stagnating and multi-resistant bacteria continue to emerge, threatening to end the "antibiotic era''. Antimicrobial peptides (AMPs) and lipo-peptides such as daptomycin offer themselves as a new potential class of antibiotics; however, further opti...

  11. Natural Cinnamic Acids, Synthetic Derivatives and Hybrids with Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Juan David Guzman

    2014-11-01

    Full Text Available Antimicrobial natural preparations involving cinnamon, storax and propolis have been long used topically for treating infections. Cinnamic acids and related molecules are partly responsible for the therapeutic effects observed in these preparations. Most of the cinnamic acids, their esters, amides, aldehydes and alcohols, show significant growth inhibition against one or several bacterial and fungal species. Of particular interest is the potent antitubercular activity observed for some of these cinnamic derivatives, which may be amenable as future drugs for treating tuberculosis. This review intends to summarize the literature data on the antimicrobial activity of the natural cinnamic acids and related derivatives. In addition, selected hybrids between cinnamic acids and biologically active scaffolds with antimicrobial activity were also included. A comprehensive literature search was performed collating the minimum inhibitory concentration (MIC of each cinnamic acid or derivative against the reported microorganisms. The MIC data allows the relative comparison between series of molecules and the derivation of structure-activity relationships.

  12. Smart silver nanoparticles: borrowing selectivity from conjugated polymers or antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    Lihong Liu

    2014-06-01

    Full Text Available Silver nanoparticles (AgNPs as novel antimicrobial agents are gaining tremendous exploration in various medical fields due to their broad spectrum activity, efficacy and low cost. The major problem associated with the AgNPs treatment is their narrow therapeutic window. To address this inherent shortcoming, significant efforts have been dedicated to reduce AgNPs cell toxicity and improve their therapeutic index. In this brief review, the emphasis would be placed on development of the combined mechanisms which can enhance the antimicrobial action of AgNPs, arising from investigating the biological differences between microbial and mammalian cells. Using one of our selected antimicrobial cell penetration peptide conjugated AgNPs as an example, we demonstrated that antimicrobial peptides (AMPs anchored AgNPs produced enhanced antimicrobial activities, possibly through multimodal mechanisms including selective binding to microorganisms and producing the intracellularly controlled Ag+ release, thus, improving the therapeutic index of AgNPs.

  13. Antimicrobial peptides targeting Gram-negative pathogens, produced and delivered by lactic acid bacteria.

    Science.gov (United States)

    Volzing, Katherine; Borrero, Juan; Sadowsky, Michael J; Kaznessis, Yiannis N

    2013-11-15

    We present results of tests with recombinant Lactococcus lactis that produce and secrete heterologous antimicrobial peptides with activity against Gram-negative pathogenic Escherichia coli and Salmonella . In an initial screening, the activities of numerous candidate antimicrobial peptides, made by solid state synthesis, were assessed against several indicator pathogenic E. coli and Salmonella strains. Peptides A3APO and Alyteserin were selected as top performers based on high antimicrobial activity against the pathogens tested and on significantly lower antimicrobial activity against L. lactis . Expression cassettes containing the signal peptide of the protein Usp45 fused to the codon-optimized sequence of mature A3APO and Alyteserin were cloned under the control of a nisin-inducible promoter PnisA and transformed into L. lactis IL1403. The resulting recombinant strains were induced to express and secrete both peptides. A3APO- and Alyteserin-containing supernatants from these recombinant L. lactis inhibited the growth of pathogenic E. coli and Salmonella by up to 20-fold, while maintaining the host's viability. This system may serve as a model for the production and delivery of antimicrobial peptides by lactic acid bacteria to target Gram-negative pathogenic bacteria populations.

  14. Antimicrobial peptides present in mammalian skin and gut are multifunctional defence molecules.

    Science.gov (United States)

    Metz-Boutigue, Marie-Hélène; Shooshtarizadeh, Peiman; Prevost, Gilles; Haikel, Youssef; Chich, Jean-François

    2010-01-01

    Antimicrobial peptides are major components of the innate immune defence. They are well conserved along evolution, non-toxic and they ensure potent defences against a large number of pathogens. They act by direct killing of microorganisms and they possess additional roles in the regulation of adaptive immune responses, by recruting or stimulating immune cells. Skin and gut are positioned at the interface of internal milieu and external environment. They represent a physical and chemical barrier against pathogens invasion and the antimicrobial peptides limit pathogen growth in normal conditions. During infection or injury, some of these peptides are overexpressed and disrupt microbial membranes and/or stimulate immune cell recruitment, allowing to return to homeostasis or to increase inflammation. Antimicrobial peptides expression is altered in several diseases: alpha-defensins deficiency is related with Crohn's disease and in skin, cathelicidin LL-37 and beta-defensin-2 are overexpressed in psoriasis, while in atopic dermatitis, their expression is decreased. The present review provides an up-to-date summary of the expression and the biological roles of the antimicrobial peptides found in the skin and gastrointestinal mucosa of the host, in normal and pathological conditions. The involvement of these natural antimicrobial peptides in inflammation, is also discussed.

  15. Self-assembled cationic peptide nanoparticles as an efficient antimicrobial agent

    Science.gov (United States)

    Liu, Lihong; Xu, Kaijin; Wang, Huaying; Jeremy Tan, P. K.; Fan, Weimin; Venkatraman, Subbu S.; Li, Lanjuan; Yang, Yi-Yan

    2009-07-01

    Antimicrobial cationic peptides are of interest because they can combat multi-drug-resistant microbes. Most peptides form α-helices or β-sheet-like structures that can insert into and subsequently disintegrate negatively charged bacterial cell surfaces. Here, we show that a novel class of core-shell nanoparticles formed by self-assembly of an amphiphilic peptide have strong antimicrobial properties against a range of bacteria, yeasts and fungi. The nanoparticles show a high therapeutic index against Staphylococcus aureus infection in mice and are more potent than their unassembled peptide counterparts. Using Staphylococcus aureus-infected meningitis rabbits, we show that the nanoparticles can cross the blood-brain barrier and suppress bacterial growth in infected brains. Taken together, these nanoparticles are promising antimicrobial agents that can be used to treat brain infections and other infectious diseases.

  16. Cloning, expression, and purification of a new antimicrobial peptide gene from Musca domestica larva.

    Science.gov (United States)

    Pei, Zhihua; Sun, Xiaoning; Tang, Yan; Wang, Kai; Gao, Yunhang; Ma, Hongxia

    2014-10-01

    Musca domestica (Diptera: Muscidae), the housefly, exhibits unique immune defences and can produce antimicrobial peptides upon stimulation with bacteria. Based on the cDNA library constructed using the suppression subtractive hybridization (SSH) method, a 198-bp antimicrobial peptide gene, which we named MDAP-2, was amplified by rapid amplification of cDNA ends (RACE) from M. domestica larvae stimulated with Salmonella pullorum (Enterobacteriaceae: Salmonella). In the present study, the full-length MDAP-2 gene was cloned and inserted into a His-tagged Escherichia coli prokaryotic expression system to enable production of the recombinant peptide. The recombinant MDAP-2 peptide was purified using Ni-NTA HisTrap FF crude column chromatography. The bacteriostatic activity of the recombinant purified MDAP-2 protein was assessed. The results indicated that MDAP-2 had in vitro antibacterial activity against all of the tested Gram- bacteria from clinical isolates, including E. coli (Enterobacteriaceae: Escherichia), one strain of S. pullorum (Enterobacteriaceae: Salmonella), and one strain of Pasteurella multocida. DNA sequencing and BLAST analysis showed that the MDAP-2 antimicrobial peptide gene was not homologous to any other antimicrobial peptide genes in GenBank. The antibacterial mechanisms of the newly discovered MDAP-2 peptide warrant further study.

  17. The contribution of skin antimicrobial peptides to the system of innate immunity in anurans.

    Science.gov (United States)

    Conlon, J Michael

    2011-01-01

    Cationic peptides with the propensity to adopt an amphipathic α-helical conformation in a membrane-mimetic environment are synthesized in the skins of many species of anurans (frogs and toads). These peptides frequently display cytolytic activities against a range of pathogenic bacteria and fungi consistent with the idea that they play a role in the host's system of innate immunity. However, the importance of the peptides in the survival strategy of the animal is not clearly understood. It is a common misconception that antimicrobial peptides are synthesized in the skins of all anurans. In fact, the species distribution is sporadic suggesting that their production may confer some evolutionary advantage to the organism but is not necessary for survival. Although growth inhibitory activity against the chytrid fungus Batrachochytrium dendrobatidis, responsible for anuran population declines worldwide, has been demonstrated in vitro, the ability of frog skin antimicrobial peptides to protect the animal in the wild appears to be limited and there is no clear correlation between their production by a species and its resistance to fatal chytridiomycosis. The low potency of many frog skin antimicrobial peptides is consistent with the hypothesis that cutaneous symbiotic bacteria may provide the major system of defense against pathogenic microorganisms in the environment with antimicrobial peptides assuming a supplementary role in some species.

  18. Rational modification of a dendrimeric peptide with antimicrobial activity: consequences on membrane-binding and biological properties.

    Science.gov (United States)

    Batoni, Giovanna; Casu, Mariano; Giuliani, Andrea; Luca, Vincenzo; Maisetta, Giuseppantonio; Mangoni, Maria Luisa; Manzo, Giorgia; Pintus, Manuela; Pirri, Giovanna; Rinaldi, Andrea C; Scorciapino, Mariano A; Serra, Ilaria; Ulrich, Anne S; Wadhwani, Parvesh

    2016-03-01

    Peptide-based antibiotics might help containing the rising tide of antimicrobial resistance. We developed SB056, a semi-synthetic peptide with a dimeric dendrimer scaffold, active against both Gram-negative and Gram-positive bacteria. Being the mechanism of SB056 attributed to disruption of bacterial membranes, we enhanced the amphiphilic profile of the original, empirically derived sequence [WKKIRVRLSA-NH2] by interchanging the first two residues [KWKIRVRLSA-NH2], and explored the effects of this modification on the interaction of peptide, both in linear and dimeric forms, with model membranes and on antimicrobial activity. Results obtained against Escherichia coli and Staphylococcus aureus planktonic strains, with or without salts at physiological concentrations, confirmed the added value of dendrimeric structure over the linear one, especially at physiological ionic strength, and the impact of the higher amphipathicity obtained through sequence modification on enhancing peptide performances. SB056 peptides also displayed intriguing antibiofilm properties. Staphylococcus epidermidis was the most susceptible strain in sessile form, notably to optimized linear analog lin-SB056-1 and the wild-type dendrimer den-SB056. Membrane affinity of all peptides increased with the percentage of negatively charged lipids and was less influenced by the presence of salt in the case of dendrimeric peptides. The analog lin-SB056-1 displayed the highest overall affinity, even for zwitterionic PC bilayers. Thus, in addition to electrostatics, distribution of charged/polar and hydrophobic residues along the sequence might have a significant role in driving peptide-lipid interaction. Supporting this view, dendrimeric analog den-SB056-1 retained greater membrane affinity in the presence of salt than den-SB056, despite the fact that they bear exactly the same net positive charge. PMID:26614437

  19. The role of mammalian antimicrobial peptides and proteins in awakening of innate host defenses and adaptive immunity.

    Science.gov (United States)

    Yang, D; Chertov, O; Oppenheim, J J

    2001-06-01

    Since we live in a dirty environment, we have developed many host defenses to contend with microorganisms. The epithelial lining of our skin, gastrointestinal tract and bronchial tree produces a number of antibacterial peptides, and our phagocytic neutrophils rapidly ingest and enzymatically degrade invading organisms, as well as produce peptides and enzymes with antimicrobial activities. Some of these antimicrobial moieties also appear to alert host cells involved in both innate host defense and adaptive immune responses. The epithelial cells are a source of constitutively produced beta defensin (HBD1) and proinflammatory cytokine-inducible beta defensins (HBD2 and -3) and cathelicidin (LL37). The neutrophils-derived antimicrobial peptides are released on demand from their cytoplasmic granules. They include the enzymes cathepsin G and chymase, azurocidin, a defensins and cathelicidin. In contrast, C5a and C3b are produced by activation of the serum complement cascade. The antimicrobial moieties direct the migration and activate target cells by interacting with selected G-protein-coupled seven-transmembrane receptors (GPCRs) on cell surfaces. The beta defensins interact with the CCR6 chemokine GPCRs, whereas cathelicidins interact with the low-affinity FPRL-1 receptors. The neutrophil-derived cathepsin G acts on the high-affinity FMLP receptor (GPCR) known as FPR, while the receptors for chymase and azurocidin have not been identified as yet. The serum-derived C5a uses a GPCR known as C5aR to mediate its chemotactic and cell-activating effects. Consequently, all these ligand-receptor interactions in addition to mediating chemotaxis also activate receptor-expressing cells to produce other mediators of inflammation.

  20. Development of Antimicrobial Peptide Prediction Tool for Aquaculture Industries.

    Science.gov (United States)

    Gautam, Aditi; Sharma, Asuda; Jaiswal, Sarika; Fatma, Samar; Arora, Vasu; Iquebal, M A; Nandi, S; Sundaray, J K; Jayasankar, P; Rai, Anil; Kumar, Dinesh

    2016-09-01

    Microbial diseases in fish, plant, animal and human are rising constantly; thus, discovery of their antidote is imperative. The use of antibiotic in aquaculture further compounds the problem by development of resistance and consequent consumer health risk by bio-magnification. Antimicrobial peptides (AMPs) have been highly promising as natural alternative to chemical antibiotics. Though AMPs are molecules of innate immune defense of all advance eukaryotic organisms, fish being heavily dependent on their innate immune defense has been a good source of AMPs with much wider applicability. Machine learning-based prediction method using wet laboratory-validated fish AMP can accelerate the AMP discovery using available fish genomic and proteomic data. Earlier AMP prediction servers are based on multi-phyla/species data, and we report here the world's first AMP prediction server in fishes. It is freely accessible at http://webapp.cabgrid.res.in/fishamp/ . A total of 151 AMPs related to fish collected from various databases and published literature were taken for this study. For model development and prediction, N-terminus residues, C-terminus residues and full sequences were considered. Best models were with kernels polynomial-2, linear and radial basis function with accuracy of 97, 99 and 97 %, respectively. We found that performance of support vector machine-based models is superior to artificial neural network. This in silico approach can drastically reduce the time and cost of AMP discovery. This accelerated discovery of lead AMP molecules having potential wider applications in diverse area like fish and human health as substitute of antibiotics, immunomodulator, antitumor, vaccine adjuvant and inactivator, and also for packaged food can be of much importance for industries. PMID:27141850

  1. Tissue expression and developmental regulation of chicken cathelicidin antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    Achanta Mallika

    2012-05-01

    Full Text Available Abstract Cathelicidins are a major family of antimicrobial peptides present in vertebrate animals with potent microbicidal and immunomodulatory activities. Four cathelicidins, namely fowlicidins 1 to 3 and cathelicidin B1, have been identified in chickens. As a first step to understand their role in early innate host defense of chickens, we examined the tissue and developmental expression patterns of all four cathelicidins. Real-time PCR revealed an abundant expression of four cathelicidins throughout the gastrointestinal, respiratory, and urogenital tracts as well as in all primary and secondary immune organs of chickens. Fowlicidins 1 to 3 exhibited a similar tissue expression pattern with the highest expression in the bone marrow and lung, while cathelicidin B1 was synthesized most abundantly in the bursa of Fabricius. Additionally, a tissue-specific regulatory pattern was evident for all four cathelicidins during the first 28 days after hatching. The expression of fowlicidins 1 to 3 showed an age-dependent increase both in the cecal tonsil and lung, whereas all four cathelicidins were peaked in the bursa on day 4 after hatching, with a gradual decline by day 28. An abrupt augmentation in the expression of fowlicidins 1 to 3 was also observed in the cecum on day 28, while the highest expression of cathelicidin B1 was seen in both the lung and cecal tonsil on day 14. Collectively, the presence of cathelicidins in a broad range of tissues and their largely enhanced expression during development are suggestive of their potential important role in early host defense and disease resistance of chickens.

  2. SYNTHESIS AND ANTIMICROBIAL STUDIES OF SOME NEW HALOGENATED ISOXAZOLINE DERIVATIVES

    OpenAIRE

    M.M. Kendre, Shahid Shaikh, N.N. Shah and M.A. Baseer*

    2013-01-01

    ABSTRACT: A series of some new Isoxazoline derivatives derived from 3-(4’-dimethylamino-phenyl)-1-(2-hydroxyphenyl)-Propenone(chalcone) derivatives using hydroxylamine hydrochloride is reported. These newly synthesized compounds were screened for their antimicrobial potencies which reflect moderate to good activity against different strains of bacteria and fungi employed. The promising feature of this reaction is mild reaction condition and excellent yield with high purity of compounds synthe...

  3. Expression analysis and identification of antimicrobial peptide transcripts from six North American frog species

    Science.gov (United States)

    Robertson, Laura S.; Fellers, Gary M.; Marranca, Jamie Marie; Kleeman, Patrick M.

    2013-01-01

    Frogs secrete antimicrobial peptides onto their skin. We describe an assay to preserve and analyze antimicrobial peptide transcripts from field-collected skin secretions that will complement existing methods for peptide analysis. We collected skin secretions from 4 North American species in the field in California and 2 species in the laboratory. Most frogs appeared healthy after release; however, Rana boylii in the Sierra Nevada foothills, but not the Coast Range, showed signs of morbidity and 2 died after handling. The amount of total RNA extracted from skin secretions was higher in R. boylii and R. sierrae compared to R. draytonii, and much higher compared to Pseudacris regilla. Interspecies variation in amount of RNA extracted was not explained by size, but for P. regilla it depended upon collection site and date. RNA extracted from skin secretions from frogs handled with bare hands had poor quality compared to frogs handled with gloves or plastic bags. Thirty-four putative antimicrobial peptide precursor transcripts were identified. This study demonstrates that RNA extracted from skin secretions collected in the field is of high quality suitable for use in sequencing or quantitative PCR (qPCR). However, some species do not secrete profusely, resulting in very little extracted RNA. The ability to measure transcript abundance of antimicrobial peptides in field-collected skin secretions complements proteomic analyses and may provide insight into transcriptional mechanisms that could affect peptide abundance.

  4. A family of helminth molecules that modulate innate cell responses via molecular mimicry of host antimicrobial peptides.

    Science.gov (United States)

    Robinson, Mark W; Donnelly, Sheila; Hutchinson, Andrew T; To, Joyce; Taylor, Nicole L; Norton, Raymond S; Perugini, Matthew A; Dalton, John P

    2011-05-01

    Over the last decade a significant number of studies have highlighted the central role of host antimicrobial (or defence) peptides in modulating the response of innate immune cells to pathogen-associated ligands. In humans, the most widely studied antimicrobial peptide is LL-37, a 37-residue peptide containing an amphipathic helix that is released via proteolytic cleavage of the precursor protein CAP18. Owing to its ability to protect against lethal endotoxaemia and clinically-relevant bacterial infections, LL-37 and its derivatives are seen as attractive candidates for anti-sepsis therapies. We have identified a novel family of molecules secreted by parasitic helminths (helminth defence molecules; HDMs) that exhibit similar biochemical and functional characteristics to human defence peptides, particularly CAP18. The HDM secreted by Fasciola hepatica (FhHDM-1) adopts a predominantly α-helical structure in solution. Processing of FhHDM-1 by F. hepatica cathepsin L1 releases a 34-residue C-terminal fragment containing a conserved amphipathic helix. This is analogous to the proteolytic processing of CAP18 to release LL-37, which modulates innate cell activation by classical toll-like receptor (TLR) ligands such as lipopolysaccharide (LPS). We show that full-length recombinant FhHDM-1 and a peptide analogue of the amphipathic C-terminus bind directly to LPS in a concentration-dependent manner, reducing its interaction with both LPS-binding protein (LBP) and the surface of macrophages. Furthermore, FhHDM-1 and the amphipathic C-terminal peptide protect mice against LPS-induced inflammation by significantly reducing the release of inflammatory mediators from macrophages. We propose that HDMs, by mimicking the function of host defence peptides, represent a novel family of innate cell modulators with therapeutic potential in anti-sepsis treatments and prevention of inflammation.

  5. Self-assembly of cationic multidomain peptide hydrogels: supramolecular nanostructure and rheological properties dictate antimicrobial activity

    Science.gov (United States)

    Jiang, Linhai; Xu, Dawei; Sellati, Timothy J.; Dong, He

    2015-11-01

    Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications.Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would

  6. High Antimicrobial Activity and Low Human Cell Cytotoxicity of Core-Shell Magnetic Nanoparticles Functionalized with an Antimicrobial Peptide.

    Science.gov (United States)

    Maleki, Hajar; Rai, Akhilesh; Pinto, Sandra; Evangelista, Marta; Cardoso, Renato M S; Paulo, Cristiana; Carvalheiro, Tiago; Paiva, Artur; Imani, Mohammad; Simchi, Abdolreza; Durães, Luísa; Portugal, António; Ferreira, Lino

    2016-05-11

    Superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with antimicrobial agents are promising infection-targeted therapeutic platforms when coupled with external magnetic stimuli. These antimicrobial nanoparticles (NPs) may offer advantages in fighting intracellular pathogens as well as biomaterial-associated infections. This requires the development of NPs with high antimicrobial activity without interfering with the biology of mammalian cells. Here, we report the preparation of biocompatible antimicrobial SPION@gold core-shell NPs based on covalent immobilization of the antimicrobial peptide (AMP) cecropin melittin (CM) (the conjugate is named AMP-NP). The minimal inhibitory concentration (MIC) of the AMP-NP for Escherichia coli was 0.4 μg/mL, 10-times lower than the MIC of soluble CM. The antimicrobial activity of CM depends on the length of the spacer between the CM and the NP. AMP-NPs are taken up by endothelial (between 60 and 170 pg of NPs per cell) and macrophage (between 18 and 36 pg of NPs per cell) cells and accumulate preferentially in endolysosomes. These NPs have no significant cytotoxic and pro-inflammatory activities for concentrations up to 200 μg/mL (at least 100 times higher than the MIC of soluble CM). Our results in membrane models suggest that the selectivity of AMP-NPs for bacteria and not eukaryotic membranes is due to their membrane compositions. The AMP-NPs developed here open new opportunities for infection-site targeting. PMID:27074633

  7. Milk-derived proteins and peptides in clinical trials

    Directory of Open Access Journals (Sweden)

    Jolanta Artym

    2013-08-01

    Full Text Available Clinical trials are reviewed, involving proteins and peptides derived from milk (predominantly bovine, with the exception of lactoferrin, which will be the subject of another article. The most explored milk fraction is α-lactalbumin (LA, which is often applied with glycomacropeptide (GMP – a casein degradation product. These milk constituents are used in health-promoting infant and adult formulae as well as in a modified form (HAMLET to treat cancer. Lactoperoxidase (LCP is used as an additive to mouth hygiene products and as a salivary substitute. Casein derivatives are applied, in addition, in the dry mouth syndrome. On the other hand, casein hydrolysates, containing active tripeptides, found application in hypertension and in type 2 diabetes. Lysozyme is routinely used for food conservation and in pharmaceutical products. It was successfully used in premature infants with concomitant diseases to improve health parameters. When used as prophylaxis in patients with scheduled surgery, it significantly reduced the incidence of hepatitis resulting from blood transfusion. Lysozyme was also used in infected children as an antimicrobial agent showing synergistic effects in combination with different antibiotics. Proline-rich polypeptide (PRP was introduced to therapy of Alzheimer’s disease patients. The therapeutic value of PRP was proved in several clinical trials and supported by studies on its mechanism of action. Concentrated immunoglobulin preparations from colostrum and milk of hyperimmunized cows showed efficacy in prevention of infections by bacteria, viruses and protozoa. A nutrition formula with milk-derived TGF-β2 (Modulen IBD® found application in treatment of pediatric Crohn’s disease. In conclusion, the preparations containing milk-derived products are safe and effective measures in prevention and treatment of infections as well as autoimmune and neoplastic diseases.

  8. Milk derived bioactive peptides and their impact on human health - A review.

    Science.gov (United States)

    Mohanty, D P; Mohapatra, S; Misra, S; Sahu, P S

    2016-09-01

    Milk-derived bioactive peptides have been identified as potential ingredients of health-promoting functional foods. These bioactive peptides are targeted at diet-related chronic diseases especially the non-communicable diseases viz., obesity, cardiovascular diseases and diabetes. Peptides derived from the milk of cow, goat, sheep, buffalo and camel exert multifunctional properties, including anti-microbial, immune modulatory, anti-oxidant, inhibitory effect on enzymes, anti-thrombotic, and antagonistic activities against various toxic agents. Majority of those regulate immunological, gastrointestinal, hormonal and neurological responses, thereby playing a vital role in the prevention of cancer, osteoporosis, hypertension and other disorders as discussed in this review. For the commercial production of such novel bioactive peptides large scale technologies based on membrane separation and ion exchange chromatography methods have been developed. Separation and identification of those peptides and their pharmacodynamic parameters are necessary to transfer their potent functional properties into food applications. The present review summarizes the preliminary classes of bioactive milk-derived peptides along with their physiological functions, general characteristics and potential applications in health-care. PMID:27579006

  9. Milk derived bioactive peptides and their impact on human health – A review

    Directory of Open Access Journals (Sweden)

    D.P. Mohanty

    2016-09-01

    Full Text Available Milk-derived bioactive peptides have been identified as potential ingredients of health-promoting functional foods. These bioactive peptides are targeted at diet-related chronic diseases especially the non-communicable diseases viz., obesity, cardiovascular diseases and diabetes. Peptides derived from the milk of cow, goat, sheep, buffalo and camel exert multifunctional properties, including anti-microbial, immune modulatory, anti-oxidant, inhibitory effect on enzymes, anti-thrombotic, and antagonistic activities against various toxic agents. Majority of those regulate immunological, gastrointestinal, hormonal and neurological responses, thereby playing a vital role in the prevention of cancer, osteoporosis, hypertension and other disorders as discussed in this review. For the commercial production of such novel bioactive peptides large scale technologies based on membrane separation and ion exchange chromatography methods have been developed. Separation and identification of those peptides and their pharmacodynamic parameters are necessary to transfer their potent functional properties into food applications. The present review summarizes the preliminary classes of bioactive milk-derived peptides along with their physiological functions, general characteristics and potential applications in health-care.

  10. Encapsulation of bioactive whey peptides in soy lecithin-derived nanoliposomes: Influence of peptide molecular weight.

    Science.gov (United States)

    Mohan, Aishwarya; McClements, David Julian; Udenigwe, Chibuike C

    2016-12-15

    Encapsulation of peptides can be used to enhance their stability, delivery and bioavailability. This study focused on the effect of the molecular weight range of whey peptides on their encapsulation within soy lecithin-derived nanoliposomes. Peptide molecular weight did not have a major impact on encapsulation efficiency or liposome size. However, it influenced peptide distribution amongst the surface, core, and bilayer regions of the liposomes, as determined by electrical charge (ζ-potential) and FTIR analysis. The liposome ζ-potential depended on peptide molecular weight, suggesting that the peptide charged groups were in different locations relative to the liposome surfaces. FTIR analysis indicated that the least hydrophobic peptide fractions interacted more strongly with choline on the liposome surfaces. The results suggested that the peptides were unequally distributed within the liposomes, even at the same encapsulation efficiency. These findings are important for designing delivery systems for commercial production of encapsulated peptides with improved functional attributes. PMID:27451165

  11. Maturation pathway of nisin and other lantibiotics : post-translationally modified antimicrobial peptides exported by Gram-positive bacteria

    NARCIS (Netherlands)

    Vos, Willem M. de; Kuipers, Oscar P.; Siezen, Roland J.

    1995-01-01

    Lantibiotics form a family of highly modified peptides which are secreted by several Gram-positive bacteria. They exhibit antimicrobial activity, mainly against other Gram-positive bacteria, by forming pores in the cellular membrane. These antimicrobial peptides are ribosomally synthesized and conta

  12. Draft Genome Sequence of Bacillus subtilis Strain NKYL29, an Antimicrobial-Peptide-Producing Strain from Soil

    OpenAIRE

    Jiang, Yanbin; Xu, Haijin; Ying LI; Liu, Hongbin; Yu, Lei; Qiao, Mingqiang; Liu, Gang

    2014-01-01

    Bacillus subtilis strain NKYL29 is an antimicrobial-peptide-producing strain isolated from the soil of Ranzhuang Tunnel in Hebei Province, China. Here, we present the draft genome of this strain, which provides the genetic basis for application of the antimicrobial peptide.

  13. Biofilms from Klebsiella pneumoniae: Matrix Polysaccharide Structure and Interactions with Antimicrobial Peptides.

    Science.gov (United States)

    Benincasa, Monica; Lagatolla, Cristina; Dolzani, Lucilla; Milan, Annalisa; Pacor, Sabrina; Liut, Gianfranco; Tossi, Alessandro; Cescutti, Paola; Rizzo, Roberto

    2016-01-01

    Biofilm matrices of two Klebsiella pneumoniae clinical isolates, KpTs101 and KpTs113, were investigated for their polysaccharide composition and protective effects against antimicrobial peptides. Both strains were good biofilm producers, with KpTs113 forming flocs with very low adhesive properties to supports. Matrix exopolysaccharides were isolated and their monosaccharide composition and glycosidic linkage types were defined. KpTs101 polysaccharide is neutral and composed only of galactose, in both pyranose and furanose ring configurations. Conversely, KpTs113 polysaccharide is anionic due to glucuronic acid units, and also contains glucose and mannose residues. The susceptibility of the two strains to two bovine cathelicidin antimicrobial peptides, BMAP-27 and Bac7(1-35), was assessed using both planktonic cultures and biofilms. Biofilm matrices exerted a relevant protection against both antimicrobials, which act with quite different mechanisms. Similar protection was also detected when antimicrobial peptides were tested against planktonic bacteria in the presence of the polysaccharides extracted from KpTs101 and KpTs113 biofilms, suggesting sequestering adduct formation with antimicrobials. Circular dichroism experiments on BMAP-27 in the presence of increasing amounts of either polysaccharide confirmed their ability to interact with the peptide and induce an α-helical conformation.

  14. Biofilms from Klebsiella pneumoniae: Matrix Polysaccharide Structure and Interactions with Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Monica Benincasa

    2016-08-01

    Full Text Available Biofilm matrices of two Klebsiella pneumoniae clinical isolates, KpTs101 and KpTs113, were investigated for their polysaccharide composition and protective effects against antimicrobial peptides. Both strains were good biofilm producers, with KpTs113 forming flocs with very low adhesive properties to supports. Matrix exopolysaccharides were isolated and their monosaccharide composition and glycosidic linkage types were defined. KpTs101 polysaccharide is neutral and composed only of galactose, in both pyranose and furanose ring configurations. Conversely, KpTs113 polysaccharide is anionic due to glucuronic acid units, and also contains glucose and mannose residues. The susceptibility of the two strains to two bovine cathelicidin antimicrobial peptides, BMAP-27 and Bac7(1–35, was assessed using both planktonic cultures and biofilms. Biofilm matrices exerted a relevant protection against both antimicrobials, which act with quite different mechanisms. Similar protection was also detected when antimicrobial peptides were tested against planktonic bacteria in the presence of the polysaccharides extracted from KpTs101 and KpTs113 biofilms, suggesting sequestering adduct formation with antimicrobials. Circular dichroism experiments on BMAP-27 in the presence of increasing amounts of either polysaccharide confirmed their ability to interact with the peptide and induce an α-helical conformation.

  15. Biofilms from Klebsiella pneumoniae: Matrix Polysaccharide Structure and Interactions with Antimicrobial Peptides.

    Science.gov (United States)

    Benincasa, Monica; Lagatolla, Cristina; Dolzani, Lucilla; Milan, Annalisa; Pacor, Sabrina; Liut, Gianfranco; Tossi, Alessandro; Cescutti, Paola; Rizzo, Roberto

    2016-01-01

    Biofilm matrices of two Klebsiella pneumoniae clinical isolates, KpTs101 and KpTs113, were investigated for their polysaccharide composition and protective effects against antimicrobial peptides. Both strains were good biofilm producers, with KpTs113 forming flocs with very low adhesive properties to supports. Matrix exopolysaccharides were isolated and their monosaccharide composition and glycosidic linkage types were defined. KpTs101 polysaccharide is neutral and composed only of galactose, in both pyranose and furanose ring configurations. Conversely, KpTs113 polysaccharide is anionic due to glucuronic acid units, and also contains glucose and mannose residues. The susceptibility of the two strains to two bovine cathelicidin antimicrobial peptides, BMAP-27 and Bac7(1-35), was assessed using both planktonic cultures and biofilms. Biofilm matrices exerted a relevant protection against both antimicrobials, which act with quite different mechanisms. Similar protection was also detected when antimicrobial peptides were tested against planktonic bacteria in the presence of the polysaccharides extracted from KpTs101 and KpTs113 biofilms, suggesting sequestering adduct formation with antimicrobials. Circular dichroism experiments on BMAP-27 in the presence of increasing amounts of either polysaccharide confirmed their ability to interact with the peptide and induce an α-helical conformation. PMID:27681920

  16. Molecular imaging probes derived from natural peptides.

    Science.gov (United States)

    Charron, C L; Hickey, J L; Nsiama, T K; Cruickshank, D R; Turnbull, W L; Luyt, L G

    2016-06-01

    Covering: up to the end of 2015.Peptides are naturally occurring compounds that play an important role in all living systems and are responsible for a range of essential functions. Peptide receptors have been implicated in disease states such as oncology, metabolic disorders and cardiovascular disease. Therefore, natural peptides have been exploited as diagnostic and therapeutic agents due to the unique target specificity for their endogenous receptors. This review discusses a variety of natural peptides highlighting their discovery, endogenous receptors, as well as their derivatization to create molecular imaging agents, with an emphasis on the design of radiolabelled peptides. This review also highlights methods for discovering new and novel peptides when knowledge of specific targets and endogenous ligands are not available. PMID:26911790

  17. End-tagging of ultra-short antimicrobial peptides by W/F stretches to facilitate bacterial killing.

    Directory of Open Access Journals (Sweden)

    Mukesh Pasupuleti

    Full Text Available BACKGROUND: Due to increasing resistance development among bacteria, antimicrobial peptides (AMPs, are receiving increased attention. Ideally, AMP should display high bactericidal potency, but low toxicity against (human eukaryotic cells. Additionally, short and proteolytically stable AMPs are desired to maximize bioavailability and therapeutic versatility. METHODOLOGY AND PRINCIPAL FINDINGS: A facile approach is demonstrated for reaching high potency of ultra-short antimicrobal peptides through end-tagging with W and F stretches. Focusing on a peptide derived from kininogen, KNKGKKNGKH (KNK10 and truncations thereof, end-tagging resulted in enhanced bactericidal effect against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Through end-tagging, potency and salt resistance could be maintained down to 4-7 amino acids in the hydrophilic template peptide. Although tagging resulted in increased eukaryotic cell permeabilization at low ionic strength, the latter was insignificant at physiological ionic strength and in the presence of serum. Quantitatively, the most potent peptides investigated displayed bactericidal effects comparable to, or in excess of, that of the benchmark antimicrobial peptide LL-37. The higher bactericidal potency of the tagged peptides correlated to a higher degree of binding to bacteria, and resulting bacterial wall rupture. Analogously, tagging enhanced peptide-induced rupture of liposomes, particularly anionic ones. Additionally, end-tagging facilitated binding to bacterial lipopolysaccharide, both effects probably contributing to the selectivity displayed by these peptides between bacteria and eukaryotic cells. Importantly, W-tagging resulted in peptides with maintained stability against proteolytic degradation by human leukocyte elastase, as well as staphylococcal aureolysin and V8 proteinase. The biological relevance of these findings was demonstrated ex vivo for pig skin infected by S. aureus and

  18. Modulation of the Activity of Secretory Phospholipase A2 by Antimicrobial Peptides

    Science.gov (United States)

    Zhao, Hongxia; Kinnunen, Paavo K. J.

    2003-01-01

    The antimicrobial peptides magainin 2, indolicidin, and temporins B and L were found to modulate the hydrolytic activity of secretory phospholipase A2 (sPLA2) from bee venom and in human lacrimal fluid. More specifically, hydrolysis of phosphatidylcholine (PC) liposomes by bee venom sPLA2 at 10 μM Ca2+ was attenuated by these peptides while augmented product formation was observed in the presence of 5 mM Ca2+. The activity of sPLA2 towards anionic liposomes was significantly enhanced by the antimicrobial peptides at low [Ca2+] and was further enhanced in the presence of 5 mM Ca2+. Similarly, with 5 mM Ca2+ the hydrolysis of anionic liposomes was enhanced significantly by human lacrimal fluid sPLA2, while that of PC liposomes was attenuated. These results indicate that concerted action of antimicrobial peptides and sPLA2 could improve the efficiency of the innate response to infections. Interestingly, inclusion of a cationic gemini surfactant in the vesicles showed an essentially similar pattern on sPLA2 activity, suggesting that the modulation of the enzyme activity by the antimicrobial peptides may involve also charge properties of the substrate surface. PMID:12604528

  19. 抗菌肽的研究及进展%Research Progress in Antimicrobial Peptides

    Institute of Scientific and Technical Information of China (English)

    姚佳; 周玉玲; 张贞; 王宁

    2012-01-01

    Antimicrobial peptides,a kind of small peptides with biological activity, widely existing in various organisms. Antimicrobial peptides are an important component of the innate immune system of organisms. Many findings suggest that antimicrobial peptides not only have the capabilities of antibacterial and inhibition, but also anti-virus and anti-tumor. Here is to summarize the activity, mechanism of action and method of artificial preparation of antimicrobial peptides, and briefly introduce its application and development in each field.%抗菌肽是一种广泛存在于各类生物体内具有生物活性的小分子多肽,它是构成机体天然免疫系统的重要组成部分.各种研究结果表示,抗菌肽不但有抗菌抑菌功能,同时还有抗病毒、抗肿瘤的功效.现对抗菌肽在抑菌活性、作用机制以及人工制备方法等进行总结,并简要介绍目前抗菌肽在各个领域的应用情况及发展进程.

  20. Antimicrobial Peptide-Driven Colloidal Transformations in Liquid-Crystalline Nanocarriers.

    Science.gov (United States)

    Gontsarik, Mark; Buhmann, Matthias T; Yaghmur, Anan; Ren, Qun; Maniura-Weber, Katharina; Salentinig, Stefan

    2016-09-01

    Designing efficient colloidal systems for the delivery of membrane active antimicrobial peptides requires in-depth understanding of their structural and morphological characteristics. Using dispersions of inverted type bicontinuous cubic phase (cubosomes), we examine the effect of integrating the amphiphilic peptide LL-37 at different concentrations on the self-assembled structure and evaluate its bactericidal ability against Escherichia coli. Small-angle X-ray scattering, dynamic light scattering, and cryogenic transmission electron microscopy show that LL-37 integrates into the bicontinuous cubic structure, inducing colloidal transformations to sponge and lamellar phases and micelles in a concentration-dependent manner. These investigations, together with in vitro evaluation studies using a clinically relevant bacterial strain, established the composition-nanostructure-activity relationship that can guide the design of new nanocarriers for antimicrobial peptides and may provide essential knowledge on the mechanisms underlying the bacterial membrane disruption with peptide-loaded nanostructures. PMID:27541048

  1. Ammonium derivatives of chromenones and quinolinones as lead antimicrobial agents

    Indian Academy of Sciences (India)

    Shilpi Gupta; Seema Singh; Abha Kathuria; Manish Kumar; Sweta Sharma; Ram Kumar; Virinder S Parmar; Bharat Singh; Anjali Gupta; Erik Van Der Eycken; Gainda L Sharma; Sunil K Sharma

    2012-03-01

    A series of novel ammonium derivatives were synthesized and examined for their antimicrobial efficacy. Comparison of antimicrobial spectrum revealed that compounds 9, 11, 16 and 23 had strong potential against pathogens in vitro. Cytotoxicity results showed compound 9 to be least toxic, it is non-toxic to A549 and U87 cells in MTT assay and exhibits marginal toxicity (15-20%) to human erythrocytes at a concentration of 1000 g/ml as compared to 100% lysis of cells by 31.25 g/ml of the standard drug amphotericin B. This compound has MIC values in the range of 1.95-31.25 g/disc in DDA against different pathogens and may considered to be an important lead antimicrobial molecule for further exploration.

  2. Albumin-derived peptides efficiently reduce renal uptake of radiolabelled peptides

    Energy Technology Data Exchange (ETDEWEB)

    Vegt, Erik; Eek, Annemarie; Oyen, Wim J.G.; Gotthardt, Martin; Boerman, Otto C. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine (444), PO Box 9101, Nijmegen (Netherlands); Jong, Marion de [Erasmus Medical Centre, Department of Nuclear Medicine, Rotterdam (Netherlands)

    2010-02-15

    In peptide-receptor radionuclide therapy (PRRT), the maximum activity dose that can safely be administered is limited by high renal uptake and retention of radiolabelled peptides. The kidney radiation dose can be reduced by coinfusion of agents that competitively inhibit the reabsorption of radiolabelled peptides, such as positively charged amino acids, Gelofusine, or trypsinised albumin. The aim of this study was to identify more specific and potent inhibitors of the kidney reabsorption of radiolabelled peptides, based on albumin. Albumin was fragmented using cyanogen bromide and six albumin-derived peptides with different numbers of electric charges were selected and synthesised. The effect of albumin fragments (FRALB-C) and selected albumin-derived peptides on the internalisation of {sup 111}In-albumin, {sup 111}In-minigastrin, {sup 111}In-exendin and {sup 111}In-octreotide by megalin-expressing cells was assessed. In rats, the effect of Gelofusine and albumin-derived peptides on the renal uptake and biodistribution of {sup 111}In-minigastrin, {sup 111}In-exendin and {sup 111}In-octreotide was determined. FRALB-C significantly reduced the uptake of all radiolabelled peptides in vitro. The albumin-derived peptides showed different potencies in reducing the uptake of {sup 111}In-albumin, {sup 111}In-exendin and {sup 111}In-minigastrin in vitro. The most efficient albumin-derived peptide (peptide 6), was selected for in vivo testing. In rats, 5 mg of peptide 6 very efficiently inhibited the renal uptake of {sup 111}In-minigastrin, by 88%. Uptake of {sup 111}In-exendin and {sup 111}In-octreotide was reduced by 26 and 33%, respectively. The albumin-derived peptide 6 efficiently inhibited the renal reabsorption of {sup 111}In-minigastrin, {sup 111}In-exendin and {sup 111}In-octreotide and is a promising candidate for kidney protection in PRRT. (orig.)

  3. Stylicins, a new family of antimicrobial peptides from the Pacific blue shrimp Litopenaeus stylirostris

    OpenAIRE

    Rolland, Jean-Luc; Abdelouahab, Mahdia; Dupont, J.; Lefevre, F.; Bachere, Evelyne; Romestand, Bernard

    2010-01-01

    The present study reports the characterization of Ls-Stylicin1, a novel antimicrobial peptide from the penaeid shrimp, Litopenoeus stylirostris. The predicted mature peptide of 82 residues is negatively charged (theoretical pl=5.0) and characterized by a proline-rich N-terminal region and a C-terminal region containing 13 cysteine residues. The recombinant Ls-Stylicin1 has been isolated in both monomeric and dimeric forms. Both display strong antifungal activity against Fusarium oxysporum (1....

  4. The role of amphibian antimicrobial peptides in protection of amphibians from pathogens linked to global amphibian declines.

    Science.gov (United States)

    Rollins-Smith, Louise A

    2009-08-01

    Amphibian species have experienced population declines and extinctions worldwide that are unprecedented in recent history. Many of these recent declines have been linked to a pathogenic skin fungus, Batrachochytrium dendrobatidis, or to iridoviruses of the genus Ranavirus. One of the first lines of defense against pathogens that enter by way of the skin are antimicrobial peptides synthesized and stored in dermal granular glands and secreted into the mucus following alarm or injury. Here, I review what is known about the capacity of amphibian antimicrobial peptides from diverse amphibians to inhibit B. dendrobatidis or ranavirus infections. When multiple species were compared for the effectiveness of their in vitro antimicrobial peptides defenses against B. dendrobatidis, non-declining species of rainforest amphibians had more effective antimicrobial peptides than species in the same habitat that had recently experienced population declines. Further, there was a significant correlation between the effectiveness of the antimicrobial peptides and resistance of the species to experimental infection. These studies support the hypothesis that antimicrobial peptides are an important component of innate defenses against B. dendrobatidis. Some amphibian antimicrobial peptides inhibit ranavirus infections and infection of human T lymphocytes by the human immunodeficiency virus (HIV). An effective antimicrobial peptide defense against skin pathogens appears to depend on a diverse array of genes expressing antimicrobial peptides. The production of antimicrobial peptides may be regulated by signals from the pathogens. However, this defense must also accommodate potentially beneficial microbes on the skin that compete or inhibit growth of the pathogens. How this delicate balancing act is accomplished is an important area of future research.

  5. Interaction of antimicrobial peptide Plantaricin149a and four analogs with lipid bilayers and bacterial membranes

    Directory of Open Access Journals (Sweden)

    José Luiz de Souza Lopes

    2013-12-01

    Full Text Available The amidated analog of Plantaricin149, an antimicrobial peptide from Lactobacillus plantarum NRIC 149, directly interacts with negatively charged liposomes and bacterial membranes, leading to their lysis. In this study, four Pln149-analogs were synthesized with different hydrophobic groups at their N-terminus with the goal of evaluating the effect of the modifications at this region in the peptide's antimicrobial properties. The interaction of these peptides with membrane models, surface activity, their hemolytic effect on red blood cells, and antibacterial activity against microorganisms were evaluated. The analogs presented similar action of Plantaricin149a; three of them with no hemolytic effect (< 5% until 0.5 mM, in addition to the induction of a helical element when binding to negative liposomes. The N-terminus difference between the analogs and Plantaricin149a retained the antibacterial effect on S. aureus and P. aeruginosa for all peptides (MIC50 of 19 µM and 155 µM to Plantaricin149a, respectively but resulted in a different mechanism of action against the microorganisms, that was bactericidal for Plantaricin149a and bacteriostatic for the analogs. This difference was confirmed by a reduction in leakage action for the analogs. The lytic activity of Plantaricin149a is suggested to be a result of the peptide-lipid interactions from the amphipathic helix and the hydrophobic residues at the N-terminus of the antimicrobial peptide.

  6. Evaluation of short synthetic antimicrobial peptides for treatment of drug-resistant and intracellular Staphylococcus aureus.

    Science.gov (United States)

    Mohamed, Mohamed F; Abdelkhalek, Ahmed; Seleem, Mohamed N

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections present a serious challenge because of the emergence of resistance to numerous conventional antibiotics. Due to their unique mode of action, antimicrobial peptides are novel alternatives to traditional antibiotics for tackling the issue of bacterial multidrug resistance. Herein, we investigated the antibacterial activity of two short novel peptides (WR12, a 12 residue peptide composed exclusively of arginine and tryptophan, and D-IK8, an eight residue β-sheet peptide) against multidrug resistant staphylococci. In vitro, both peptides exhibited good antibacterial activity against MRSA, vancomycin-resistant S. aureus, linezolid-resistant S. aureus, and methicillin-resistant S. epidermidis. WR12 and D-IK8 were able to eradicate persisters, MRSA in stationary growth phase, and showed significant clearance of intracellular MRSA in comparison to both vancomycin and linezolid. In vivo, topical WR12 and D-IK8 significantly reduced both the bacterial load and the levels of the pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in MRSA-infected skin lesions. Moreover, both peptides disrupted established in vitro biofilms of S. aureus and S. epidermidis significantly more so than traditional antimicrobials tested. Taken together, these results support the potential of WR12 and D-IK8 to be used as a topical antimicrobial agent for the treatment of staphylococcal skin infections. PMID:27405275

  7. Applications of Circular Dichroism for Structural Analysis of Gelatin and Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Yoonkyung Park

    2012-03-01

    Full Text Available Circular dichroism (CD is a useful technique for monitoring changes in the conformation of antimicrobial peptides or gelatin. In this study, interactions between cationic peptides and gelatin were observed without affecting the triple helical content of the gelatin, which was more strongly affected by anionic surfactant. The peptides did not adopt a secondary structure in the presence of aqueous solution or Tween 80, but a peptide secondary structure formed upon the addition of sodium dodecyl sulfate (SDS. The peptides bound to the phosphate group of lipopolysaccharide (LPS and displayed an alpha-helical conformation while (KW4 adopted a folded conformation. Further, the peptides did not specifically interact with the fungal cell wall components of mannan or laminarin. Tryptophan blue shift assay indicated that these peptides interacted with SDS, LPS, and gelatin but not with Tween 80, mannan, or laminarin. The peptides also displayed antibacterial activity against P. aeruginosa without cytotoxicity against HaCaT cells at MIC, except for HPA3NT3-analog peptide. In this study, we used a CD spectroscopic method to demonstrate the feasibility of peptide characterization in numerous environments. The CD method can thus be used as a screening method of gelatin-peptide interactions for use in wound healing applications.

  8. SYNTHESIS AND ANTIMICROBIAL STUDIES OF SOME NEW HALOGENATED ISOXAZOLINE DERIVATIVES

    Directory of Open Access Journals (Sweden)

    M.M. Kendre, Shahid Shaikh, N.N. Shah and M.A. Baseer*

    2013-03-01

    Full Text Available ABSTRACT: A series of some new Isoxazoline derivatives derived from 3-(4’-dimethylamino-phenyl-1-(2-hydroxyphenyl-Propenone(chalcone derivatives using hydroxylamine hydrochloride is reported. These newly synthesized compounds were screened for their antimicrobial potencies which reflect moderate to good activity against different strains of bacteria and fungi employed. The promising feature of this reaction is mild reaction condition and excellent yield with high purity of compounds synthesized. All the synthesized compounds were confirmed by IR, 1HNMR and Mass.

  9. Gene expression of oncogenes, antimicrobial peptides, and cytokines in the development of oral leukoplakia.

    NARCIS (Netherlands)

    Wenghoefer, M.; Pantelis, A.; Najafi, T.; Deschner, J.; Allam, J.P.; Novak, N.; Reich, R.; Martini, M.; Berge, S.J.; Fischer, H.P.; Jepsen, S.; Winter, J.

    2010-01-01

    OBJECTIVE: The aim of this study was to investigate the expression pattern of oncogenes, antimicrobial peptides, and genes involved in inflammation in leukoplakia of the oral cavity compared with healthy gingiva. STUDY DESIGN: Biopsies of healthy gingiva (n=20) and leukoplakia (n=20), were obtained

  10. Divorcing folding from function: how acylation affects the membrane-perturbing properties of an antimicrobial peptide

    DEFF Research Database (Denmark)

    Vad, Brian Stougaard; Thomsen, Line Aagot Hede; Bertelsen, Kresten;

    2010-01-01

    Many small cationic peptides, which are unstructured in aqueous solution, have antimicrobial properties. These properties are assumed to be linked to their ability to permeabilize bacterial membranes, accompanied by the transition to an alpha-helical folding state. Here we show that there is no d...

  11. Simulation studies of the interaction of antimicrobial peptides and lipid bilayers

    NARCIS (Netherlands)

    La Rocca, P; Biggin, PC; Tieleman, DP; Sansom, MSP

    1999-01-01

    Experimental studies of a number of antimicrobial peptides are sufficiently detailed to allow computer simulations to make a significant contribution to understanding their mechanisms of action at an atomic level. In this review we focus on simulation studies of alamethicin, melittin, dermaseptin an

  12. Effects of hydrophobicity on the antifungal activity of alpha-helical antimicrobial peptides.

    NARCIS (Netherlands)

    Jiang, Z.; Kullberg, B.J.; Lee, H van der; Vasil, A.I.; Hale, J.D.; Mant, C.T.; Hancock, R.E.; Vasil, M.L.; Netea, M.G.; Hodges, R.S.

    2008-01-01

    We utilized a series of analogs of D-V13K (a 26-residue amphipathic alpha-helical antimicrobial peptide, denoted D1) to compare and contrast the role of hydrophobicity on antifungal and antibacterial activity to the results obtained previously with Pseudomonas aeruginosa strains. Antifungal activity

  13. Improvement of Solubility and Stability of the Antimicrobial Peptide Nisin by Protein Engineering

    NARCIS (Netherlands)

    Rollema, Harry S.; Kuipers, Oscar P.; Both, Paula; Vos, Willem M. de; Siezen, Roland J.

    1995-01-01

    Nisin is a 3.4-kDa antimicrobial peptide that, as a result of posttranslational modifications, contains unsaturated amino acids and lanthionine residues. It is applied as a preservative in various food products. The solubility and stability of nisin and nisin mutants have been studied. It is demonst

  14. Characterization and Activity of an Immobilized Antimicrobial Peptide Containing Bactericidal PEG-Hydrogel

    NARCIS (Netherlands)

    Cleophas, Rik T. C.; Sjollema, Jelmer; Busscher, Henk J.; Kruijtzer, John A. W.; Liskamp, Rob M. J.

    2014-01-01

    A single step immobilization-polymerization strategy of a highly active antimicrobial peptide into a soft hydrogel network on a poly(ethylene terephthalate) surface using thiol-ene chemistry is described. The bactericidal hydrogel was molecularly characterized via Coomassie and Lowry assay protein s

  15. Characterization and activity of an immobilized antimicrobial peptide containing bactericidal PEG-hydrogel

    NARCIS (Netherlands)

    Cleophas, Rik T C; Sjollema, Jelmer; Busscher, Henk J; Kruijtzer, John A W; Liskamp, Rob M J

    2014-01-01

    A single step immobilization-polymerization strategy of a highly active antimicrobial peptide into a soft hydrogel network on a poly(ethylene terephthalate) surface using thiol-ene chemistry is described. The bactericidal hydrogel was molecularly characterized via Coomassie and Lowry assay protein s

  16. Stylicins, a new family of antimicrobial peptides from the Pacific blue shrimp Litopenaeus stylirostris.

    Science.gov (United States)

    Rolland, J L; Abdelouahab, M; Dupont, J; Lefevre, F; Bachère, E; Romestand, B

    2010-03-01

    The present study reports the characterization of Ls-Stylicin1, a novel antimicrobial peptide from the penaeid shrimp, Litopenaeus stylirostris. The predicted mature peptide of 82 residues is negatively charged (theoretical pI=5.0) and characterized by a proline-rich N-terminal region and a C-terminal region containing 13 cysteine residues. The recombinant Ls-Stylicin1 has been isolated in both monomeric and dimeric forms. Both display strong antifungal activity against Fusarium oxysporum (1.25 microMantimicrobial activity against Gram (-) bacteria, Vibrio sp. (40 microMantimicrobial peptides but identified herein several species of penaeid shrimp is thought to be the first member of a shrimp antimicrobial peptide family, which we termed stylicins. PMID:20061030

  17. Rational Design of alpha-helical antimicrobial peptides: DOs and DON’Ts

    DEFF Research Database (Denmark)

    Uggerhøj, Lars Erik; Poulsen, Tanja Juul; Munk, Jens K.;

    2015-01-01

    Antimicrobial peptides (AMPs) are promising candidates for battling multiresistant bacteria. Despite extensive research, structure–activity relationships of AMPs are not fully understood, and there is a lack of structural data relating to AMPs in lipids. Here we present the NMR structure of anopl...

  18. In vitro growth of growth of campylobacter spp. inhibited by selected antimicrobial peptides

    Science.gov (United States)

    Background: Novel alternatives to traditional antibiotics are urgently needed for food-animal production. A goal of our laboratory is to develop and evaluate antimicrobial peptides (AMP) to control and reduce foodborne pathogens in poultry. AMP have been found in most every class of living organism...

  19. The pharmacokinetics and pharmacodynamics of progastrin-derived peptides

    DEFF Research Database (Denmark)

    Hansen, Carsten Palnaes

    2003-01-01

    The elimination of progastrin-derived peptides was a first-order process, also at supraphysiological concentrations in plasma. The site of extraction was dependent on the molecular size of the peptides and not on their bioactivity. Apart from the kidneys and brain, where the extraction was nonsel...

  20. Synthetic antimicrobial and LPS-neutralising peptides suppress inflammatory and immune responses in skin cells and promote keratinocyte migration.

    Science.gov (United States)

    Pfalzgraff, Anja; Heinbockel, Lena; Su, Qi; Gutsmann, Thomas; Brandenburg, Klaus; Weindl, Günther

    2016-01-01

    The stagnation in the development of new antibiotics and the concomitant high increase of resistant bacteria emphasize the urgent need for new therapeutic options. Antimicrobial peptides are promising agents for the treatment of bacterial infections and recent studies indicate that Pep19-2.5, a synthetic anti-lipopolysaccharide (LPS) peptide (SALP), efficiently neutralises pathogenicity factors of Gram-negative (LPS) and Gram-positive (lipoprotein/-peptide, LP) bacteria and protects against sepsis. Here, we investigated the potential of Pep19-2.5 and the structurally related compound Pep19-4LF for their therapeutic application in bacterial skin infections. SALPs inhibited LP-induced phosphorylation of NF-κB p65 and p38 MAPK and reduced cytokine release and gene expression in primary human keratinocytes and dermal fibroblasts. In LPS-stimulated human monocyte-derived dendritic cells and Langerhans-like cells, the peptides blocked IL-6 secretion, downregulated expression of maturation markers and inhibited dendritic cell migration. Both SALPs showed a low cytotoxicity in all investigated cell types. Furthermore, SALPs markedly promoted cell migration via EGFR transactivation and ERK1/2 phosphorylation and accelerated artificial wound closure in keratinocytes. Peptide-induced keratinocyte migration was mediated by purinergic receptors and metalloproteases. In contrast, SALPs did not affect proliferation of keratinocytes. Conclusively, our data suggest a novel therapeutic target for the treatment of patients with acute and chronic skin infections. PMID:27509895

  1. An effective zinc phthalocyanine derivative for photodynamic antimicrobial chemotherapy

    International Nuclear Information System (INIS)

    Bacterial infection is a common clinical problem. The emergence of antibiotic resistant bacteria posts a severe challenge to medical practice worldwide. Photodynamic antimicrobial chemotherapy (PACT) uses laser light at specific wavelength to activate oxygen molecule in the human tissue into reactive oxygen species as antimicrobial agent. This activation of oxygen by laser light is mediated through a photosensitizer. Two key properties for potent photosensitizer are its absorbance of light in the infrared region (630–700 nm), which promotes tissue penetration depth, and the selective accumulation on bacteria instead of human tissue. We herein report a zinc phthalocyanine derivative, pentalysine β-carbonylphthalocyanine zinc (ZnPc-(Lys)5) and its antimicrobial effects in vitro and in an animal infection model. This photosensitizer has strong capability to kill bacteria at 670 nm. Chemically, it is a water-soluble and cationic photosensitizer carrying positive charge under physiological pH, and can specifically target to bacteria which usually bears negative charges on its surface. Compared with anionic ZnPc counterparts, ZnPc-(Lys)5 shows a higher phototoxicity toward bacteria. PACT studies of ZnPc-(Lys)5 in experimental infection animal model showed a significant bacteria inhibition compared to controls, and high selectivity of ZnPc-(Lys)5 toward bacteria. These findings suggest ZnPc-(Lys)5 is a promising antimicrobial photosensitizer for the treatment of infectious diseases. - Highlights: • Photodynamic antimicrobial chemotherapy (PACT) with water-soluble zinc phthalocyanine derivative offers a promising measure to deal with antibiotic resistance of bacteria. • The use of portable LED light sources that are battery-powered and with low cost may make possible the deployment of systems that can be used for wound decontamination. • ZnPc-(Lys)5 is a potent photosensitizer for treatment of infectious diseases

  2. An effective zinc phthalocyanine derivative for photodynamic antimicrobial chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhuo, E-mail: zchen@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry and Danish-Chinese Centre for Proteases and Cancer, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Zhou, Shanyong; Chen, Jincan [State Key Laboratory of Structural Chemistry and Danish-Chinese Centre for Proteases and Cancer, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Li, Linsen [Department of Biochemistry, Shenyang Medical College, Shenyang, Liaoning 110034 (China); Hu, Ping; Chen, Song [State Key Laboratory of Structural Chemistry and Danish-Chinese Centre for Proteases and Cancer, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Huang, Mingdong, E-mail: mhuang@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry and Danish-Chinese Centre for Proteases and Cancer, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2014-08-01

    Bacterial infection is a common clinical problem. The emergence of antibiotic resistant bacteria posts a severe challenge to medical practice worldwide. Photodynamic antimicrobial chemotherapy (PACT) uses laser light at specific wavelength to activate oxygen molecule in the human tissue into reactive oxygen species as antimicrobial agent. This activation of oxygen by laser light is mediated through a photosensitizer. Two key properties for potent photosensitizer are its absorbance of light in the infrared region (630–700 nm), which promotes tissue penetration depth, and the selective accumulation on bacteria instead of human tissue. We herein report a zinc phthalocyanine derivative, pentalysine β-carbonylphthalocyanine zinc (ZnPc-(Lys){sub 5}) and its antimicrobial effects in vitro and in an animal infection model. This photosensitizer has strong capability to kill bacteria at 670 nm. Chemically, it is a water-soluble and cationic photosensitizer carrying positive charge under physiological pH, and can specifically target to bacteria which usually bears negative charges on its surface. Compared with anionic ZnPc counterparts, ZnPc-(Lys){sub 5} shows a higher phototoxicity toward bacteria. PACT studies of ZnPc-(Lys){sub 5} in experimental infection animal model showed a significant bacteria inhibition compared to controls, and high selectivity of ZnPc-(Lys){sub 5} toward bacteria. These findings suggest ZnPc-(Lys){sub 5} is a promising antimicrobial photosensitizer for the treatment of infectious diseases. - Highlights: • Photodynamic antimicrobial chemotherapy (PACT) with water-soluble zinc phthalocyanine derivative offers a promising measure to deal with antibiotic resistance of bacteria. • The use of portable LED light sources that are battery-powered and with low cost may make possible the deployment of systems that can be used for wound decontamination. • ZnPc-(Lys){sub 5} is a potent photosensitizer for treatment of infectious diseases.

  3. Synthesis and antimicrobial activity of amphiphilic carbohydrate derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Roberta C.N.; Oda, Simone C.; Almeida, Mauro V. de; Le Hyaric, Mireille [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Dept. de Quimica]. E-mail: mireille.hyaric@ufjf.edu.br; Lourenco, Maria C.S.; Vicente, Felipe R.C. [Fundacao Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil ). Instituto de Pesquisa Clinica Evandro Chagas (IPEC); Barbosa, Nadia R.; Trevizani, Rafael; Santos, Priscila L.C. [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Faculdade de Farmacia e Bioquimica

    2008-07-01

    N-monoalkylated diamines were synthesised and treated with D-ribonolactone or D-gluconolactone. The resulting aldonamides were evaluated for their antimicrobial activity against S. aureus, E. coli, M. tuberculosis and C. albicans. Two hydrazides were also prepared from ribonohydrazide and their biological activity was compared to their amide analogues. All the ribono-derivatives displayed moderated antitubercular activity, and some of them were also active against S. aureus. (author)

  4. Three-dimensional structure in lipid micelles of the pediocin-like antimicrobial peptide curvacin A.

    Science.gov (United States)

    Haugen, Helen Sophie; Fimland, Gunnar; Nissen-Meyer, Jon; Kristiansen, Per Eugen

    2005-12-13

    The 3D structure of the membrane-permeabilizing 41-mer pediocin-like antimicrobial peptide curvacin A produced by lactic acid bacteria has been studied by NMR spectroscopy. In DPC micelles, the cationic and hydrophilic N-terminal half of the peptide forms an S-shaped beta-sheet-like domain stabilized by a disulfide bridge and a few hydrogen bonds. This domain is followed by two alpha-helices: a hydrophilic 6-mer helix between residues 19 and 24 and an amphiphilic/hydrophobic 11-mer helix between residues 29 and 39. There are two hinges in the peptide, one at residues 16-18 between the N-terminal S-shaped beta-sheet-like structure and the central 6-mer helix and one at residues 26-28 between the central helix and the 11-mer C-terminal helix. The latter helix is the only amphiphilic/hydrophobic part of the peptide and is thus presumably the part that penetrates into the hydrophobic phase of target-cell membranes. The hinge between the two helices may introduce the flexibility that allows the helix to dip into membranes. The helix-hinge-helix structure in the C-terminal half of curvacin A clearly distinguishes this peptide from the other pediocin-like peptides whose structures have been analyzed and suggests that curvacin A along with the structural homologues enterocin P and carnobacteriocin BM1 belong to a subgroup of the pediocin-like family of antimicrobial peptides. PMID:16331975

  5. Evaluation of the immunogenicity and in vivo toxicity of the antimicrobial peptide P34.

    Science.gov (United States)

    Vaucher, Rodrigo de Almeida; Velho Gewehr, Camila de Campos Velho; Correa, Ana Paula Folmer; Sant'Anna, Voltaire; Ferreira, Juliano; Brandelli, Adriano

    2011-12-12

    Immunogenicity and toxicity of antimicrobial peptide P34 were evaluated in vivo. BALB/c mice were inoculated intraperitoneally with peptide P34 alone and associated with Freund's adjuvant. For acute toxicity testing, different concentrations of the peptide P34 (82.5, 165.0, 247.5 and 330.0mg/kg) were orally administered. To evaluate the sub-chronic toxicity the tested dose of 0.825 mg/kg/day of the peptide P34 or nisin were administered for 21 days. There were no hypersensitivity reactions or significant increase in antibody titer during the immunogenicity experiment or death of animals during the acute or sub-chronic toxicity tests. The LD(50) was higher than 332.3 ± 0.76 mg/kg. No significant changes in serum biochemical parameters were observed in the animals treated with the peptide P34 unlike nisin-treated group showed a significant increase in alanine transaminase levels in comparison to controls. The group treated with 0.825 mg/kg/day of nisin showed histological changes in the spleen, skin and liver. In the group treated with peptide P34 histological changes in the spleen were observed, with the presence of megakaryocytes. Few studies report the use of animal models to evaluate the in vivo toxicity of antimicrobial peptides and such investigation is an essential step to ensure it safe use in foods.

  6. Cation-pi interactions stabilize the structure of the antimicrobial peptide indolicidin near membranes: molecular dynamics simulations

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Kaznessis, Yiannis N

    2007-01-01

    We implemented molecular dynamics simulations of the 13-residue antimicrobial peptide indolicidin (ILPWKWPWWPWRR-NH2) in dodecylphosphocholine (DPC) and sodium dodecyl sulfate (SDS) micelles. In DPC, a persistent cation-pi interaction between TRP11 and ARG13 defined the structure of the peptide...... to the sulfate groups leads to an extended peptide structure. To the best of our knowledge, this is the first time that a cation-pi interaction between peptide side chains has been shown to stabilize the structure of a small antimicrobial peptide. The simulations are in excellent agreement with available...... experimental measurements: the backbone of the peptide is more ordered in DPC than in SDS; the tryptophan side chains pack against the backbone in DPC and point away from the backbone in SDS; the rms fluctuation of the peptide backbone and peptide side chains is greater in SDS than in DPC; and the peptide...

  7. Synthesis and Biological Activity of Peptide Derivatives of Iodoquinazolinones/Nitroimidazoles

    Directory of Open Access Journals (Sweden)

    Rakesh Yadav

    2008-04-01

    Full Text Available Two substituted quinazolinyl/imidazolyl-salicylic acids 5, 6 were synthesized bythe reaction of 6-iodo-2-methylbenzoxazin-4-one/5-nitroimidazole with 5-aminosalicylicacid (5-ASA. Coupling of compounds 5 and 6 with different amino acid esterhydrochlorides, dipeptide and tripeptide methyl esters yielded novelquinazolino/imidazolopeptide derivatives 5a-f and 6a-g. The chemical structures of allnewly synthesized compounds were confirmed by means of FT-IR, 1H- and 13C-NMR, MSand elemental analysis. Selected peptide ester derivatives were further hydrolyzed by usinglithium hydroxide (LiOH to afford the corresponding acid derivatives 5ba-da and 6ea-ga.All peptide derivatives were assayed for antimicrobial and anthelmintic activities againsteight pathogenic microbes and three earthworm species. Among the tested compounds, 5e,5d, 6e and their hydrolyzed analogs 5da and 6ea exhibited higher antimicrobial activityagainst Pseudomonas aeruginosa, Klebsiella pneumoniae and Candida albicans, and 5a,6g and 6ga displayed better antifungal activity against the dermatophytes Trichophytonmentagrophytes and Microsporum audouinii. Moreover, 6f and its hydrolyzed derivative6fa showed good anthelmintic activity against Megascoplex konkanensis, Pontoscotexcorethruses and Eudrilus eugeniea at dose of 2 mg mL–1.

  8. Surface modification and properties of Bombyx mori silk fibroin films by antimicrobial peptide

    Science.gov (United States)

    Bai, Liqiang; Zhu, Liangjun; Min, Sijia; Liu, Lin; Cai, Yurong; Yao, Juming

    2008-03-01

    The Bombyx mori silk fibroin films (SFFs) were modified by a Cecropin B ( CB) antimicrobial peptide, (NH 2)-NGIVKAGPAIAVLGEAAL-CONH 2, using the carbodiimide chemistry method. In order to avoid the dissolution of films during the modification procedure, the SFFs were first treated with 60% (v/v) ethanol aqueous solution, resulting a structural transition from unstable silk I to silk II. The investigation of modification conditions showed that the surface-modified SFFs had the satisfied antimicrobial activity and durability when they were activated by EDC·HCl/NHS solution followed by a treatment in CB peptide/PBS buffer (pH 6.5 or 8) solution at ambient temperature for 2 h. Moreover, the surface-modified SFFs showed the smaller contact angle due to the hydrophilic antimicrobial peptides coupled on the film surface, which is essential for the cell adhesion and proliferation. AFM results indicated that the surface roughness of SFFs was considerably increased after the modification by the peptides. The elemental composition analysis results also suggested that the peptides were tightly coupled to the surface of SFFs. This approach may provide a new option to engineer the surface-modified implanted materials preventing the biomaterial-centered infection (BCI).

  9. Surface modification and properties of Bombyx mori silk fibroin films by antimicrobial peptide

    International Nuclear Information System (INIS)

    The Bombyx mori silk fibroin films (SFFs) were modified by a Cecropin B (CB) antimicrobial peptide, (NH2)-NGIVKAGPAIAVLGEAAL-CONH2, using the carbodiimide chemistry method. In order to avoid the dissolution of films during the modification procedure, the SFFs were first treated with 60% (v/v) ethanol aqueous solution, resulting a structural transition from unstable silk I to silk II. The investigation of modification conditions showed that the surface-modified SFFs had the satisfied antimicrobial activity and durability when they were activated by EDC.HCl/NHS solution followed by a treatment in CB peptide/PBS buffer (pH 6.5 or 8) solution at ambient temperature for 2 h. Moreover, the surface-modified SFFs showed the smaller contact angle due to the hydrophilic antimicrobial peptides coupled on the film surface, which is essential for the cell adhesion and proliferation. AFM results indicated that the surface roughness of SFFs was considerably increased after the modification by the peptides. The elemental composition analysis results also suggested that the peptides were tightly coupled to the surface of SFFs. This approach may provide a new option to engineer the surface-modified implanted materials preventing the biomaterial-centered infection (BCI)

  10. Lipid membrane structure and dynamics in the presence of tamoxifen and antimicrobial peptides

    Science.gov (United States)

    Hebenstreit, Samuel; Khadka, Nawal; Pan, Jianjun

    2015-03-01

    Lipids are organic molecules composed of hydrophobic fatty acid tails and hydrophilic head groups that can form a multitude of structures, including lipid vesicles which provides an excellent model representing cell membranes. In this study, we examine the effects of antimicrobial peptides and drugs on lipid vesicles. Fourier transform infrared spectroscopy measurements are performed with and without the antimicrobial peptide. A change in absorbance corresponding to the wavenumber regimes associated with the stretching of the carbonyl and phosphate groups is observed. Also, a dye leakage assay is performed with vesicles composed of neutral and charged lipids. Calcein dye is enclosed within these vesicles in solution. Different concentrations of the active and inactive antimicrobial peptides, and tamoxifen are incubated with the vesicles. Concentration dependent dye leakage is determined by measuring fluorescence intensity before and after the addition of the peptides and tamoxifen. Different leakage behavior is observed for the active and inactive peptides, and the lipid composition of the vesicle is found to have a large effect. Supported by an NSF grant.

  11. Two novel antimicrobial peptides purified from the symbiotic bacteria Xenorhabdus budapestensis NMC-10.

    Science.gov (United States)

    Xiao, Yao; Meng, Fanlu; Qiu, Dewen; Yang, Xiufen

    2012-06-01

    Symbiotic bacteria, which are carried in the intestinal vesicle of the infective stage of juvenile entomopathogenic nematodes, produce broad-spectrum antibiotics. In this study, we aimed to isolate the antimicrobial peptides from the culture of the entomopathogenic bacterium Xenorhabdus budapestensis NMC-10. By screening chromatography columns and optimizing flow rate, pH, salinity and other purification conditions, we identified the final purification procedures which consisted of Q ion-exchange chromatography, gel filtration chromatography and two-step reverse-phase chromatography. Two novel antimicrobial peptides were identified via Q-TOF-TOF and de novo sequencing, and designated as GP-19 and EP-20. Both natural and synthetic peptides demonstrated broad-spectrum antimicrobial activities. The synthetic GP-19 peptide was active against Verticillium dahlia with EC(50) values of 17.54 μg/ml and highly inhibited the growth of a variety of bacteria, while the synthetic EP-20 peptide was highly active against Phytophthora capsici with EC(50) values of 3.14 μg/ml. PMID:22497806

  12. Isolation and partial purification of antimicrobial peptides/proteins from dung beetle, Onthophagus taurus immune hemolymph

    International Nuclear Information System (INIS)

    Antimicrobial peptides are important in the first line of the host defense system of all insect species. In the present study antimicrobial peptide(s) were isolated from the hemolymph of the dung beetle Onthophagus taurus. Both non induced and immune induced hemolymphs were tested for their antimicrobial activity against different bacterial strains and C. albicans. Induction was done by injecting E. coli into the abdominal cavity of the O. taurus. The non induced hemolymph did not show activity against any of the tested fungal and bacterial strains where as induced hemolymph showed activity against all tested bacterial strains but no activity against C. albicans. The induced hemolymph was subjected to non reducing SDS-PAGE and UV wavelength scan was performed to detect the presence of peptides. The immune induced hemolymph was purified by gel filtration chromatography to separate the proteins responsible for the antibacterial activity. The fractions within the peak were tested against those bacteria which previously showed sensitivity to the crude immune induced hemolymph. All fractions were found to be active against all tested bacteria with difference in zone of inhibition. The peptides are active against prokaryotes and not against eukaryotes. These properties reveal its unique characteristics and therapeutic application. (author)

  13. ISOLATION AND PARTIAL PURIFICATION OF ANTIMICROBIAL PEPTIDES/PROTEINS FROM DUNG BEETLE, ONTHOPHAGUS TAURUS IMMUNE HEMOLYMPH

    Directory of Open Access Journals (Sweden)

    Vasanth Patil H.B

    2013-06-01

    Full Text Available Antimicrobial peptides are important in the first line of the host defense system of all insect species. In the present study antimicrobial peptide(s were isolated from the hemolymph of the dung beetle Onthophagus taurus. Both non induced and immune induced hemolymphs were tested for their antimicrobial activity against different bacterial strains and C. albicans. Induction was done by injecting E. coli into the abdominal cavity of the O. taurus. The non induced hemolymph did not show activity against any of the tested fungal and bacterial strains where as induced hemolymph showed activity against all tested bacterial strains but no activity against C. albicans. The induced hemolymph was subjected to non reducing SDS-PAGE and UV wavelength scan was performed to detect the presence of peptides. The immune induced hemolymph was purified by gel filtration chromatography to separate the proteins responsible for the antibacterial activity. The fractions within the peak were tested against those bacteria which previously showed sensitivity to the crude immune induced hemolymph. All fractions were found to be active against all tested bacteria with difference in zone of inhibition. The peptides are active against prokaryotes & not against eukaryotes. These properties reveal its unique characteristics and therapeutic application.

  14. Antimicrobial and host-defense peptides as new anti-infective therapeutic strategies.

    Science.gov (United States)

    Hancock, Robert E W; Sahl, Hans-Georg

    2006-12-01

    Short cationic amphiphilic peptides with antimicrobial and/or immunomodulatory activities are present in virtually every life form, as an important component of (innate) immune defenses. These host-defense peptides provide a template for two separate classes of antimicrobial drugs. Direct-acting antimicrobial host-defense peptides can be rapid-acting and potent, and possess an unusually broad spectrum of activity; consequently, they have prospects as new antibiotics, although clinical trials to date have shown efficacy only as topical agents. But for these compounds to fulfill their therapeutic promise and overcome clinical setbacks, further work is needed to understand their mechanisms of action and reduce the potential for unwanted toxicity, to make them more resistant to protease degradation and improve serum half-life, as well as to devise means of manufacturing them on a large scale in a consistent and cost-effective manner. In contrast, the role of cationic host-defense peptides in modulating the innate immune response and boosting infection-resolving immunity while dampening potentially harmful pro-inflammatory (septic) responses gives these peptides the potential to become an entirely new therapeutic approach against bacterial infections.

  15. Gallinacin and Fowlicidin: Two Promising Antimicrobial Peptides in ChickensAND#8212;A Review

    Directory of Open Access Journals (Sweden)

    C. S. Mukhopadhyaya

    2010-12-01

    Full Text Available Antimicrobial peptides (AMP which have been identified in almost all groups of organisms, are the small cationic molecules that recognize the pathogen associated molecular patterns of the microbes. In chicken two main AMPs that play significant roles in bolstering the innate immunity are gallinacins and fowlicidins, which are the functional analogues of the mammalian beta-defensins and cathelicidins. Gallinacin identifies the Gram negative bacteria while fowlicidin exerts broad spectral activity. The basic mechanism of action is by far similar in both groups of AMPs. The ‘docking sites’ of these antimicrobial peptides includes the “lipid A” moiety of lipo polysaccharides, lipo-teichoic acids, anionic membrane phospholipids on bacterial surfaces. These AMPs block the DNA replication and protein synthesis in bacteria causing death of the microbe. Researchers have identified reproducible molecular markers of those peptides for selection of disease resistant stock of chickens. [Vet. World 2010; 3(6.000: 297-300

  16. Novel antimicrobial peptides that inhibit gram positive bacterial exotoxin synthesis.

    Directory of Open Access Journals (Sweden)

    Joseph A Merriman

    Full Text Available Gram-positive bacteria, such as Staphylococcus aureus, cause serious human illnesses through combinations of surface virulence factors and secretion of exotoxins. Our prior studies using the protein synthesis inhibitor clindamycin and signal transduction inhibitors glycerol monolaurate and α-globin and β-globin chains of hemoglobin indicate that their abilities to inhibit exotoxin production by S. aureus are separable from abilities to inhibit growth of the organism. Additionally, our previous studies suggest that inhibition of exotoxin production, in absence of ability to kill S. aureus and normal flora lactobacilli, will prevent colonization by pathogenic S. aureus, while not interfering with lactobacilli colonization. These disparate activities may be important in development of novel anti-infective agents that do not alter normal flora. We initiated studies to explore the exotoxin-synthesis-inhibition activity of hemoglobin peptides further to develop potential agents to prevent S. aureus infections. We tested synthesized α-globin chain peptides, synthetic variants of α-globin chain peptides, and two human defensins for ability to inhibit exotoxin production without significantly inhibiting S. aureus growth. All of these peptides were weakly or not inhibitory to bacterial growth. However, the peptides were inhibitory to exotoxin production with increasing activity dependent on increasing numbers of positively-charged amino acids. Additionally, the peptides could be immobilized on agarose beads or have amino acid sequences scrambled and still retain exotoxin-synthesis-inhibition. The peptides are not toxic to human vaginal epithelial cells and do not inhibit growth of normal flora L. crispatus. These peptides may interfere with plasma membrane signal transduction in S. aureus due to their positive charges.

  17. Food-Derived Bioactive Peptides on Inflammation and Oxidative Stress

    OpenAIRE

    Subhadeep Chakrabarti; Forough Jahandideh; Jianping Wu

    2014-01-01

    Chronic diseases such as atherosclerosis and cancer are now the leading causes of morbidity and mortality worldwide. Inflammatory processes and oxidative stress underlie the pathogenesis of these pathological conditions. Bioactive peptides derived from food proteins have been evaluated for various beneficial effects, including anti-inflammatory and antioxidant properties. In this review, we summarize the roles of various food-derived bioactive peptides in inflammation and oxidative stress and...

  18. Antimicrobial Evaluation and Synthesis of Some Phenylpyrazolo benzothiazolo quinoxaline Derivatives

    Directory of Open Access Journals (Sweden)

    CH. Sridevi

    2009-01-01

    Full Text Available 2,3-Diphenyl quinoxaline (SI was fused with 2-amino benzothiazoles (SII by a methylene bridge, which was then allowed for acetylation. The acetylated product (SIV was made to react with different aromatic aldehydes to give chalcones (SV1-SV5. Chalcones refluxed with substituted acid hydrazides to afford different phenyl pyrazolo benzothiazolo quinoxaline derivatives (SVI1-SVI15. The structure of chalcones and phenyl pyrazolo benzothiazolo quinoxaline derivatives were confirmed by M.P, TLC and spectral data. All the synthesized compounds were screened for their antimicrobial activities.

  19. Effects of D-Lysine Substitutions on the Activity and Selectivity of Antimicrobial Peptide CM15

    Directory of Open Access Journals (Sweden)

    Heather M. Kaminski

    2011-12-01

    Full Text Available Despite their potent antimicrobial activity, the usefulness of antimicrobial peptides (AMPs as antibiotics has been limited by their toxicity to eukaryotic cells and a lack of stability in vivo. In the present study we examined the effects of introducing D-lysine residues into a 15-residue hybrid AMP containing residues 1–7 of cecropin A and residues 2–9 of melittin (designated CM15. Diastereomeric analogs of CM15 containing between two and five D-lysine substitutions were evaluated for their antimicrobial activity, lysis of human erythrocytes, toxicity to murine macrophages, ability to disrupt cell membranes, and protease stability. All of the analogs caused rapid permeabilization of the Staphylococcus aureus cell envelope, as indicated by uptake of SYTOX green. Permeabilization of the plasma membrane of RAW264.7 macrophages was also observed for CM15, but this was substantially diminished for the D-lysine containing analogs. The introduction of D-lysine caused moderate decreases in antimicrobial activity for all analogs studied, with a much more pronounced reduction in toxicity to eukaryotic cells, leading to marked improvements in antimicrobial efficacy. Circular dichroism studies indicated a progressive loss of helical secondary structure upon introduction of D-lysine residues, with a good correspondence between helical content and eukaryotic cell cytotoxicity. Overall, these studies indicate that disruption of amphipathic secondary structure reduces both antimicrobial activity and eukaryotic cell toxicity, but that the reduction in eukaryotic cell cytotoxicity is more pronounced, leading to an overall gain in antimicrobial selectivity.

  20. Molecular cloning, expression and in vitro analysis of soluble cationic synthetic antimicrobial peptide from salt-inducible Escherichia coli GJ1158

    Directory of Open Access Journals (Sweden)

    Jawahar Babu Peravali

    2013-01-01

    Full Text Available Antimicrobial peptides are the upcoming therapeutic molecules as alternative drugs to the existing antibiotics owing to their potent action against pathogenic microorganisms. In this study, to obtain an antimicrobial peptide with a broad range of activity, the synthetic cationic antimicrobial peptide was designed by using in silico tools viz., antimicrobial peptide database, protparam, hierarchical neural network. Later, the peptide was translated back into a core nucleotide sequence and the gene for the peptide was constructed by overlapping PCR. The amplified gene was cloned into pRSET–A vector and transformed into salt inducible expression host E. coli GJ1158. The expression results show high yields of soluble recombinant fusion peptide (0.52 g/L from salt-inducible E. coli. The recombinant peptide was purified by the IMAC purification system and cleaved by enterokinase. The digested product was further purified and 0.12 g/L of biologically active recombinant cationic antimicrobial peptide was obtained. In vitro analysis of the purified peptide demonstrated high antimicrobial activity against both Gram positive and Gram negative bacteria devoid of hemolytic activity. Therefore, this synthetic cationic antimicrobial peptide could serves as an promising agent over chemical antibiotics. In this study, a synthetic cationic antimicrobial peptide was designed, cloned and expressed from salt-inducible E. coli GJ1158 using cost effective media in the large scale production of antimicrobial peptide and its biological activity was analysed against different Gram positive and negative organisms.

  1. Membrane aggregation and perturbation induced by antimicrobial peptide of S-thanatin

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Guoqiu, E-mail: guoqiuwu@163.com [Center of Clinical Laboratory Medicine of Zhongda Hospital, Southeast University, Nanjing (China); Wu, Hongbin; Li, Linxian; Fan, Xiaobo; Ding, Jiaxuan; Li, Xiaofang; Xi, Tao [Biotechnology Center, Department of Life Science and Biotechnology, China Pharmaceutical University, Nanjing 210009 (China); Shen, Zilong, E-mail: Zilongshen@sina.com [Biotechnology Center, Department of Life Science and Biotechnology, China Pharmaceutical University, Nanjing 210009 (China)

    2010-04-23

    Thanatin, a 21-residue peptide, is an inducible insect peptide. In our previous study, we have identified a novel thanatin analog of S-thanatin, which exhibited a broad antimicrobial activity against bacteria and fungi with low hemolytic activity. This study was aimed to delineate the antimicrobial mechanism of S-thanatin and identify its interaction with bacterial membranes. In this study, membrane phospholipid was found to be the target for S-thanatin. In the presence of vesicles, S-thanatin interestingly led to the aggregation of anionic vesicles and sonicated bacteria. Adding S-thanatin to Escherichia coli suspension would result in the collapse of membrane and kill bacteria. The sensitivity assay of protoplast elucidated the importance of outer membrane (OM) for S-thanatin's antimicrobial activity. Compared with other antimicrobial peptide, S-thanatin produced chaotic membrane morphology and cell debris in electron microscopic appearance. These results supported our hypothesis that S-thanatin bound to negatively charged LPS and anionic lipid, impeded membrane respiration, exhausted the intracellular potential, and released periplasmic material, which led to cell death.

  2. Temporin-SHf, a New Type of Phe-rich and Hydrophobic Ultrashort Antimicrobial Peptide*

    Science.gov (United States)

    Abbassi, Feten; Lequin, Olivier; Piesse, Christophe; Goasdoué, Nicole; Foulon, Thierry; Nicolas, Pierre; Ladram, Ali

    2010-01-01

    Because issues of cost and bioavailability have hampered the development of gene-encoded antimicrobial peptides to combat infectious diseases, short linear peptides with high microbial cell selectivity have been recently considered as antibiotic substitutes. A new type of short antimicrobial peptide, designated temporin-SHf, was isolated and cloned from the skin of the frog Pelophylax saharica. Temporin-SHf has a highly hydrophobic sequence (FFFLSRIFa) and possesses the highest percentage of Phe residues of any known peptide or protein. Moreover, it is the smallest natural linear antimicrobial peptide found to date, with only eight residues. Despite its small size and hydrophobicity, temporin-SHf has broad-spectrum microbicidal activity against Gram-positive and Gram-negative bacteria and yeasts, with no hemolytic activity. CD and NMR spectroscopy combined with restrained molecular dynamics calculations showed that the peptide adopts a well defined non-amphipathic α-helical structure from residue 3 to 8, when bound to zwitterionic dodecyl phosphocholine or anionic SDS micelles. Relaxation enhancement caused by paramagnetic probes showed that the peptide adopts nearly parallel orientations to the micelle surface and that the helical structure is stabilized by a compact hydrophobic core on one face that penetrates into the micelle interior. Differential scanning calorimetry on multilamellar vesicles combined with membrane permeabilization assays on bacterial cells indicated that temporin-SHf disrupts the acyl chain packing of anionic lipid bilayers, thereby triggering local cracks and microbial membrane disintegration through a detergent-like effect probably via the carpet mechanism. The short length, compositional simplicity, and broad-spectrum activity of temporin-SHf make it an attractive candidate to develop new antibiotic agents. PMID:20308076

  3. Blood-brain barrier transport of short proline-rich antimicrobial peptides.

    Science.gov (United States)

    Stalmans, Sofie; Wynendaele, Evelien; Bracke, Nathalie; Knappe, Daniel; Hoffmann, Ralf; Peremans, Kathelijne; Polis, Ingeborgh; Burvenich, Christian; De Spiegeleer, Bart

    2014-04-01

    Infections by antibiotic-resistant bacteria are becoming a great risk for human health, leading to an urgent need for new efficient antibacterial therapies. The short, proline-rich antimicrobial peptides from insects gained a lot of interest as a potential antibacterial treatment, having a low toxicity profile and being mainly active against Gram-negative bacteria. To know whether these antimicrobial peptides can be used for the treatment of cerebral infections, the blood-brain barrier transport characteristics of these peptides were investigated. This study describes the results of the in vivo blood-brain barrier experiments in mice, as well as the in vitro metabolic stability in mouse plasma and brain of apidaecin Api137, oncocin, drosocin and drosocin Pro5Hyp. The four investigated peptides showed a significant influx into the brain with a K(in) ranging between 0.37 and 0.86 µL/g x min and brain distribution volumes of 19.6 to 25.8 µL/g. Only for drosocin, a significant efflux was determined, with a k(out) of 0.22 min(-1). After entering the brain, oncocin was for approximately 80% trapped in the endothelial cells, while the other peptides reached the brain parenchyma for about 70%. All peptides were stable in plasma and brain during the experiments, with estimated metabolic half-lives ranging between 47 min and 637 min. We conclude that the investigated short, proline-rich antimicrobial peptides show an influx into the brain, which make them a promising antibacterial treatment of cerebral infections.

  4. Synthesis and Antimicrobial Characterization of Half-Calycanthaceous Alkaloid Derivatives.

    Science.gov (United States)

    Zheng, Shaojun; Zhou, Xinping; Xu, Shixun; Zhu, Rui; Bai, Hongjin; Zhang, Jiwen

    2016-01-01

    A total of 29 novel tetrahydropyrroloindol-based calycanthaceous alkaloid derivatives were synthesized from indole-3-acetonitrile in good yields. The synthesized compounds were evaluated against nine strains of bacteria and a wide range of plant pathogen fungi. Bioassay results revealed that majority of the compounds displayed similar or higher in vitro antimicrobial activities than the positive control. The biological activities also indicated that substituents at R₄ and R₅ significantly affect the activities. Notably, compound c4 was found to be most active among the tested calycanthaceous analogues and might be a novel potential leading compound for further development as an antifungal agent. The results could pave the way for further design and structural modification of calycanthaceous alkaloids as antimicrobial agents. PMID:27618003

  5. Driving engineering of novel antimicrobial peptides from simulations of peptide-micelle interactions

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Langham, Allison A; Kaznessis, Yiannis N

    2006-01-01

    peptides and their interaction with membrane mimics. In this article, we discuss the promise and the challenges of widely used models and detail our recent work on peptide-micelle simulations as an attractive alternative to peptide-bilayer simulations. We detail our results with two large structural...

  6. Ancient antimicrobial peptides kill antibiotic-resistant pathogens: Australian mammals provide new options.

    Directory of Open Access Journals (Sweden)

    Jianghui Wang

    Full Text Available BACKGROUND: To overcome the increasing resistance of pathogens to existing antibiotics the 10×'20 Initiative declared the urgent need for a global commitment to develop 10 new antimicrobial drugs by the year 2020. Naturally occurring animal antibiotics are an obvious place to start. The recently sequenced genomes of mammals that are divergent from human and mouse, including the tammar wallaby and the platypus, provide an opportunity to discover novel antimicrobials. Marsupials and monotremes are ideal potential sources of new antimicrobials because they give birth to underdeveloped immunologically naïve young that develop outside the sterile confines of a uterus in harsh pathogen-laden environments. While their adaptive immune system develops innate immune factors produced either by the mother or by the young must play a key role in protecting the immune-compromised young. In this study we focus on the cathelicidins, a key family of antimicrobial peptide genes. PRINCIPAL FINDING: We identified 14 cathelicidin genes in the tammar wallaby genome and 8 in the platypus genome. The tammar genes were expressed in the mammary gland during early lactation before the adaptive immune system of the young develops, as well as in the skin of the pouch young. Both platypus and tammar peptides were effective in killing a broad range of bacterial pathogens. One potent peptide, expressed in the early stages of tammar lactation, effectively killed multidrug-resistant clinical isolates of Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii. CONCLUSIONS AND SIGNIFICANCE: Marsupial and monotreme young are protected by antimicrobial peptides that are potent, broad spectrum and salt resistant. The genomes of our distant relatives may hold the key for the development of novel drugs to combat multidrug-resistant pathogens.

  7. Antimicrobial combinations: Bliss independence and Loewe additivity derived from mechanistic multi-hit models.

    Science.gov (United States)

    Baeder, Desiree Y; Yu, Guozhi; Hozé, Nathanaël; Rolff, Jens; Regoes, Roland R

    2016-05-26

    Antimicrobial peptides (AMPs) and antibiotics reduce the net growth rate of bacterial populations they target. It is relevant to understand if effects of multiple antimicrobials are synergistic or antagonistic, in particular for AMP responses, because naturally occurring responses involve multiple AMPs. There are several competing proposals describing how multiple types of antimicrobials add up when applied in combination, such as Loewe additivity or Bliss independence. These additivity terms are defined ad hoc from abstract principles explaining the supposed interaction between the antimicrobials. Here, we link these ad hoc combination terms to a mathematical model that represents the dynamics of antimicrobial molecules hitting targets on bacterial cells. In this multi-hit model, bacteria are killed when a certain number of targets are hit by antimicrobials. Using this bottom-up approach reveals that Bliss independence should be the model of choice if no interaction between antimicrobial molecules is expected. Loewe additivity, on the other hand, describes scenarios in which antimicrobials affect the same components of the cell, i.e. are not acting independently. While our approach idealizes the dynamics of antimicrobials, it provides a conceptual underpinning of the additivity terms. The choice of the additivity term is essential to determine synergy or antagonism of antimicrobials.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160596

  8. Killer bee molecules: antimicrobial peptides as effector molecules to target sporogonic stages of Plasmodium.

    Directory of Open Access Journals (Sweden)

    Victoria Carter

    Full Text Available A new generation of strategies is evolving that aim to block malaria transmission by employing genetically modified vectors or mosquito pathogens or symbionts that express anti-parasite molecules. Whilst transgenic technologies have advanced rapidly, there is still a paucity of effector molecules with potent anti-malaria activity whose expression does not cause detrimental effects on mosquito fitness. Our objective was to examine a wide range of antimicrobial peptides (AMPs for their toxic effects on Plasmodium and anopheline mosquitoes. Specifically targeting early sporogonic stages, we initially screened AMPs for toxicity against a mosquito cell line and P. berghei ookinetes. Promising candidate AMPs were fed to mosquitoes to monitor adverse fitness effects, and their efficacy in blocking rodent malaria infection in Anopheles stephensi was assessed. This was followed by tests to determine their activity against P. falciparum in An. gambiae, initially using laboratory cultures to infect mosquitoes, then culminating in preliminary assays in the field using gametocytes and mosquitoes collected from the same area in Mali, West Africa. From a range of 33 molecules, six AMPs able to block Plasmodium development were identified: Anoplin, Duramycin, Mastoparan X, Melittin, TP10 and Vida3. With the exception of Anoplin and Mastoparan X, these AMPs were also toxic to an An. gambiae cell line at a concentration of 25 µM. However, when tested in mosquito blood feeds, they did not reduce mosquito longevity or egg production at concentrations of 50 µM. Peptides effective against cultured ookinetes were less effective when tested in vivo and differences in efficacy against P. berghei and P. falciparum were seen. From the range of molecules tested, the majority of effective AMPs were derived from bee/wasp venoms.

  9. Computational promoter analysis of mouse, rat and human antimicrobial peptide-coding genes

    Directory of Open Access Journals (Sweden)

    Kai Chikatoshi

    2006-12-01

    Full Text Available Abstract Background Mammalian antimicrobial peptides (AMPs are effectors of the innate immune response. A multitude of signals coming from pathways of mammalian pathogen/pattern recognition receptors and other proteins affect the expression of AMP-coding genes (AMPcgs. For many AMPcgs the promoter elements and transcription factors that control their tissue cell-specific expression have yet to be fully identified and characterized. Results Based upon the RIKEN full-length cDNA and public sequence data derived from human, mouse and rat, we identified 178 candidate AMP transcripts derived from 61 genes belonging to 29 AMP families. However, only for 31 mouse genes belonging to 22 AMP families we were able to determine true orthologous relationships with 30 human and 15 rat sequences. We screened the promoter regions of AMPcgs in the three species for motifs by an ab initio motif finding method and analyzed the derived promoter characteristics. Promoter models were developed for alpha-defensins, penk and zap AMP families. The results suggest a core set of transcription factors (TFs that regulate the transcription of AMPcg families in mouse, rat and human. The three most frequent core TFs groups include liver-, nervous system-specific and nuclear hormone receptors (NHRs. Out of 440 motifs analyzed, we found that three represent potentially novel TF-binding motifs enriched in promoters of AMPcgs, while the other four motifs appear to be species-specific. Conclusion Our large-scale computational analysis of promoters of 22 families of AMPcgs across three mammalian species suggests that their key transcriptional regulators are likely to be TFs of the liver-, nervous system-specific and NHR groups. The computationally inferred promoter elements and potential TF binding motifs provide a rich resource for targeted experimental validation of TF binding and signaling studies that aim at the regulation of mouse, rat or human AMPcgs.

  10. Molecular dynamics simulations of the helical antimicrobial peptide ovispirin-1 in a zwitterionic dodecylphosphocholine micelle

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Kaznessis, Yiannis N

    2005-01-01

    We have carried out a 40-ns all-atom molecular dynamics simulation of the helical antimicrobial peptide ovispirin-1 (OVIS) in a zwitterionic diphosphocholine (DPC) micelle. The DPC micelle serves as an economical and effective model for a cellular membrane owing to the presence of a choline...... headgroup, which resembles those of membrane phospholipids. OVIS, which was initially placed along a micelle diameter, diffuses out to the water-DPC interface, and the simulation stabilizes to an interface-bound steady state in 40 ns. The helical content of the peptide marginally increases in the process....... The final conformation, orientation, and the structure of OVIS are in excellent agreement with the experimentally observed properties of the peptide in the presence of lipid bilayers composed of 75% zwitterionic lipids. The amphipathic peptide binds to the micelle with its hydrophobic face buried...

  11. Cost-effective expression and purification of antimicrobial and host defense peptides in Escherichia coli

    DEFF Research Database (Denmark)

    Bommarius, B.; Jenssen, Håvard; Elliott, M.;

    2010-01-01

    to their therapeutic application. High manufacturing costs associated with amino acid precursors have limited the delivery of inexpensive therapeutics through industrial-scale chemical synthesis. Conversely, the production of peptides in bacteria by recombinant DNA technology has been impeded by the antimicrobial...... activity of these peptides and their susceptibility to proteolytic degradation, while subsequent purification of recombinant peptides often requires multiple steps and has not been cost-effective. Here we have developed methodologies appropriate for large-scale industrial production of HDPs; in particular......, CRAMP, HHC-10, E5 and E6). Using this technology, pilot-scale fermentation (10 L) was performed to produce large quantities of biologically active cationic peptides. Together, these data indicate that this new method represents a cost-effective means to enable commercial enterprises to produce HDPs...

  12. Enzymatic fractionation of the antimicrobial peptides casocidin and isracidin by Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus

    Science.gov (United States)

    The cumulative effect of peptidase and protease activities associated with cells of Streptococcus thermophilus (ST) and Lactobacillus delbrueckii subsp. bulgaricus (LB) was evaluated on the milk-protein based antimicrobial peptides casocidin and isracidin. Reaction mixtures of casocidin or isracidin...

  13. Parallel activities and interactions between antimicrobial peptides and complement in host defense at the airway epithelial surface.

    Science.gov (United States)

    Hiemstra, Pieter S

    2015-11-01

    Antimicrobial peptides and complement components contribute to host defense as well as inflammation and tissue injury in the respiratory tract. The airway epithelial surface is the main site of action of these immune effectors, and airway epithelial cells contribute markedly to their local production. Whereas both antimicrobial peptides and complement display overlapping functions, it is increasingly clear that both effector mechanisms also interact. Furthermore, excessive or uncontrolled release of antimicrobial peptides as well as complement activation may contribute to inflammatory lung diseases. Therefore, further knowledge of interactions between these systems may provide more insight into the pathogenesis of a range of lung diseases. In this review, recent findings on the functions, collaborations and other interactions between antimicrobial peptides and complement are discussed with a specific focus on the airway epithelium.

  14. The species-specific mode of action of the antimicrobial peptide subtilosin against Listeria monocytogenes Scott A

    NARCIS (Netherlands)

    Kuijk, van S.J.A.; Noll, K.S.; Chikindas, M.L.

    2012-01-01

    Aims: To elucidate the molecular mechanism of action of the antimicrobial peptide subtilosin against the foodborne pathogen Listeria monocytogenes Scott A. Methods and Results: Subtilosin was purified from a culture of Bacillus amylliquefaciens. The minimal inhibitory concentration of subtilosin aga

  15. Adrenaline modulates the global transcriptional profile of Salmonella revealing a role in the antimicrobial peptide and oxidative stress resistance responses

    Directory of Open Access Journals (Sweden)

    Williams P

    2008-10-01

    cue for the induction of the Salmonella stress response in anticipation of imminent host-derived oxidative stress. However, adrenaline may also serve in favour of the host defences by lowering antimicrobial peptide resistance and hence documenting for the first time such a function for a hormone.

  16. Antimicrobial Peptide LL-37 and IDR-1 Ameliorate MRSA Pneumonia in Vivo

    Directory of Open Access Journals (Sweden)

    Man Hou

    2013-09-01

    Full Text Available Background: The only human cathelicidin, LL-37, and the innate defense regulator peptide IDR-1, which have been proven to have antimicrobial activity, represent essential elements of immunity. Our previous study showed that the peptide LL-37 was protective in vitro to attenuate LTA-induced inflammatory effects. Methicillin-resistant staphylococcus aureus (MRSA causes a multitude of serious and sometimes life-threatening diseases around the globe. However, the effect of LL-37 and IDR-1 in MRSA-induced pneumonia is unknown. In the present study, we explored the potential of LL-37 and IDR-1 in ameliorating MRSA-induced pneumonia in vivo. Methods: C57BL/6 mice were randomly divided into four groups and perfused intratracheally with PBS, peptide, MRSA and MRSA plus peptide, respectively. Pulmonary tissue pathology, ELISA and quantitative RT-PCR were employed. The relative signal pathways were further explored by western blot analysis. Results: Pathological analysis of the lung tissue sections demonstrated that, when compared with the MRSA-treated group, both the LL-37 and IDR-1 could ameliorate the MRSA-induced pneumonia. The phosphorylation of JNK and Akt were markedly decreased in the peptide plus MRSA-treated group compared with the MRSA-treated group. Furthermore, both of them also reduced TNF-α and IL-6 production in the bronchoalveolar lavage fluid (BALF and serum in vivo. Conclusion: We report the first evidence of peptides inhibiting inflammation, decreasing the release of inflammatory cytokines and restoring pulmonary function in vivo. The antimicrobial peptide LL-37 and IDR-1 could ameliorate MRSA-induced pneumonia by exerting an anti-inflammatory property and attenuating pro-inflammatory cytokine release, thus providing support for the hypothesis that both innate and synthetic peptides could protect against MRSA in vivo.

  17. Structural location determines functional roles of the basic amino acids of KR-12, the smallest antimicrobial peptide from human cathelicidin LL-37.

    Science.gov (United States)

    Mishra, Biswajit; Epand, Raquel F; Epand, Richard M; Wang, Guangshun

    2013-11-14

    Cationic antimicrobial peptides are recognized templates for developing a new generation of antimicrobials to combat superbugs. Human cathelicidin LL-37 is an essential host defense molecule in human innate immunity. Previously, we identified KR-12 as the smallest antibacterial peptide of LL-37. KR-12 has a narrow activity spectrum since it is active against Gram-negative Escherichia coli but not Gram-positive Staphylococcus aureus. The functional roles of the basic amino acids of KR-12, however, have not yet been elucidated. An alanine scan of cationic amino acids of KR-12 provided evidence for their distinct roles in the activities of the peptides. Bacterial killing and membrane permeation experiments indicate that the R23A and K25A mutants, as well as the lysine-to-arginine mutant, were more potent than KR-12. Another three cationic residues (K18, R19, and R29) of KR-12, which are located in the hydrophilic face of the amphiphathic helix, appeared to be more important in clustering anionic lipids or hemolysis than R23 and K25 in the interfacial region. While the loss of interfacial R23 or K25 reduced peptide helicity, underscoring its important role in membrane binding, the overall increase in peptide activity of KR-12 could be ascribed to the increased peptide hydrophobicity that outweighed the role of basic charge in this case. In contrast, the mutations of interfacial R23 or K25 reduced peptide bactericidal activity of GF-17, an overlapping, more hydrophobic and potent peptide also derived from LL-37. Thus, the hydrophobic context of the peptide determines whether an alanine substitution of an interfacial basic residue increases or decreases membrane permeation and peptide activity.

  18. APD3: the antimicrobial peptide database as a tool for research and education.

    Science.gov (United States)

    Wang, Guangshun; Li, Xia; Wang, Zhe

    2016-01-01

    The antimicrobial peptide database (APD, http://aps.unmc.edu/AP/) is an original database initially online in 2003. The APD2 (2009 version) has been regularly updated and further expanded into the APD3. This database currently focuses on natural antimicrobial peptides (AMPs) with defined sequence and activity. It includes a total of 2619 AMPs with 261 bacteriocins from bacteria, 4 AMPs from archaea, 7 from protists, 13 from fungi, 321 from plants and 1972 animal host defense peptides. The APD3 contains 2169 antibacterial, 172 antiviral, 105 anti-HIV, 959 antifungal, 80 antiparasitic and 185 anticancer peptides. Newly annotated are AMPs with antibiofilm, antimalarial, anti-protist, insecticidal, spermicidal, chemotactic, wound healing, antioxidant and protease inhibiting properties. We also describe other searchable annotations, including target pathogens, molecule-binding partners, post-translational modifications and animal models. Amino acid profiles or signatures of natural AMPs are important for peptide classification, prediction and design. Finally, we summarize various database applications in research and education. PMID:26602694

  19. Combined Bioinformatic and Rational Design Approach To Develop Antimicrobial Peptides against Mycobacterium tuberculosis

    Science.gov (United States)

    Pearson, C. Seth; Kloos, Zachary; Murray, Brian; Tabe, Ebot; Gupta, Monica; Kwak, Jun Ha; Karande, Pankaj

    2016-01-01

    Drug-resistant pathogens are a growing problem, and novel strategies are needed to combat this threat. Among the most significant of these resistant pathogens is Mycobacterium tuberculosis, which is an unusually difficult microbial target due to its complex membrane. Here, we design peptides for specific activity against M. tuberculosis using a combination of “database filtering” bioinformatics, protein engineering, and de novo design. Several variants of these peptides are structurally characterized to validate the design process. The designed peptides exhibit potent activity (MIC values as low as 4 μM) against M. tuberculosis and also exhibit broad activity against a host of other clinically relevant pathogenic bacteria such as Gram-positive bacteria (Streptococcus) and Gram-negative bacteria (Escherichia coli). They also display excellent selectivity, with low cytotoxicity against cultured macrophages and lung epithelial cells. These first-generation antimicrobial peptides serve as a platform for the design of antibiotics and for investigating structure-activity relationships in the context of the M. tuberculosis membrane. The antimicrobial peptide design strategy is expected to be generalizable for any pathogen for which an activity database can be created. PMID:26902758

  20. Combined Bioinformatic and Rational Design Approach To Develop Antimicrobial Peptides against Mycobacterium tuberculosis.

    Science.gov (United States)

    Pearson, C Seth; Kloos, Zachary; Murray, Brian; Tabe, Ebot; Gupta, Monica; Kwak, Jun Ha; Karande, Pankaj; McDonough, Kathleen A; Belfort, Georges

    2016-05-01

    Drug-resistant pathogens are a growing problem, and novel strategies are needed to combat this threat. Among the most significant of these resistant pathogens is Mycobacterium tuberculosis, which is an unusually difficult microbial target due to its complex membrane. Here, we design peptides for specific activity against M. tuberculosis using a combination of "database filtering" bioinformatics, protein engineering, and de novo design. Several variants of these peptides are structurally characterized to validate the design process. The designed peptides exhibit potent activity (MIC values as low as 4 μM) against M. tuberculosis and also exhibit broad activity against a host of other clinically relevant pathogenic bacteria such as Gram-positive bacteria (Streptococcus) and Gram-negative bacteria (Escherichia coli). They also display excellent selectivity, with low cytotoxicity against cultured macrophages and lung epithelial cells. These first-generation antimicrobial peptides serve as a platform for the design of antibiotics and for investigating structure-activity relationships in the context of the M. tuberculosis membrane. The antimicrobial peptide design strategy is expected to be generalizable for any pathogen for which an activity database can be created.

  1. Effect of synthetic antimicrobial peptides on Naegleria fowleri trophozoites.

    Science.gov (United States)

    Tiewcharoen, Supathra; Phurttikul, Watchara; Rabablert, Jundee; Auewarakul, Prasert; Roytrakul, Sittiruk; Chetanachan, Pruksawan; Atithep, Thassanant; Junnu, Virach

    2014-05-01

    We evaluated the effect of tritrpticin, lactoferrin, killer decapeptide and scrambled peptide in vitro against Naegleria fowleri trophozoites compared with amphotericin B. Tritrpticin (100 microg/ml) caused apoptosis of N. fowleri trophozoites (2x10(5) cells/ml), while lactoferrin, killer decapeptide and scrambled peptide did not. On Gormori trichrome staining, tritrpticin affected the elasticity of the surface membrane and reduced the size of the nuclei of N. fowleri trophozoites. The ultrastructure surface membrane and food cup formation of the trophozoites were 100% inhibited. These results are consistent with inhibition of the nfa1, Mp2CL5 of the treated trophozoite, which plays a role in food cup formation. Tritrpticin 100 microg/ml was not toxic against SK-N-MC cells. Our findings suggest tritrpticin has activity against the surface membrane and nfa1 and Mp2CL5 of N. fowleri trophozoites and could be developed as a potential therapeutic agent.

  2. A relationship between antimicrobial peptide gene expression and capacity of a selected shrimp line to survive a Vibrio infection

    OpenAIRE

    de Lorgeril, Julien; Gueguen, Yannick; Goarant, Cyrille; Goyard, Emmanuel; Mugnier, Chantal; Fievet, Julie; Piquemal, D.; Bachere, Evelyne

    2008-01-01

    Understanding of antimicrobial defence mechanisms of penaeid shrimp should help in the design of efficient strategies for the management and disease control in aquaculture. In this study, we have specifically analysed the expression in circulating hemocytes of antimicrobial peptides (AMPs) encoding genes, such as PEN2 and PEN3, ALF, crustin, lysozyme and a putative cysteine-rich peptide. We evidenced a relationship between the level of expression of some AMPs and the successful response of th...

  3. A cecropin-like antimicrobial peptide with anti-inflammatory activity from the black fly salivary glands

    OpenAIRE

    WU, Jing; Mu, Lixian; Zhuang, Li; Han, Yi; Liu, Tong; Jun LI; Yang, Yuan; Yang, Hailong; Wei, Lin

    2015-01-01

    Background Several antimicrobial peptides (AMPs) belonging to the cecropin family have been identified from the salivary glands of different black fly species, however, the immunological functions for these molecules were poorly understood. Methods A novel cecropin-like antimicrobial peptide (SibaCec) was purified using reverse phase high-performance liquid chromatography (RP-HPLC) from the salivary glands of the black fly Simulium bannaense. The amino acid sequence of SibaCec was determined ...

  4. Enhanced membrane pore information by multimeric/oligomeric antimicrobial peptides

    OpenAIRE

    Arnusch, C.J.; Branderhorst, H.M.; de Kruijff, B.; Liskamp, R. M. J.; Breukink, E.J.; Pieters, R. J.

    2007-01-01

    The pore-forming antibacterial peptide magainin 2 was made divalent, tetravalent, and octavalent via a copper(I)-mediated 1-3 dipolar cycloaddition reaction (“click” chemistry). This series of poreforming compounds was tested in vitro for their ability to form pores in large unilamillar vesicles (LUVs). A large increase in the pore-forming capability was especially observed with the tetravalent and octavalent magainin compounds in the LUVs consisting of DOPC, and the octavalent magainin compo...

  5. Synthesis, antimicrobial and antioxidative activity of some new isatin derivatives

    Directory of Open Access Journals (Sweden)

    Šekularac Gavrilo M.

    2014-01-01

    Full Text Available The isatin derivatives, Schiff bases, were synthesized by the reaction of isatin and various substituted primary amines and characterized by several spectroscopic methods. Investigation of the antimicrobial activity of the synthesized compounds was performed by the agar dilution method, against different strains of bacteria and one fungi. The antioxidative activity of the synthesized compounds was also determined. Some of the compounds have shown the significant activity against the selected strains of microorganisms and the antioxidative activity. [Projekat Ministarstva nauke Republike Srbije, br. 172013 i III 46010

  6. Synthesis of Novel Quinazoline Derivatives as Antimicrobial Agents

    Institute of Scientific and Technical Information of China (English)

    ALY,A.A

    2003-01-01

    Quinazoline isothiocyanate 1 reacts with various nucleophiles(nitrogen nucleophiles,oxygen nucleophiles and sulphur nucleophiles)to afford heterocyclic systemes 2-13,Also,the [4+2] cycloaddition reaction of 1 with phenyl isocyanate,benzylidene aryl amine and cinnamic acid derivatives gave novel heterocyclic compounds 14-16,Moreover,the reaction of 1 with active methylene compounds under Michael reaction conditions also was investigated to yield 17 and 18 and it was found that all these reactions proceede via isothiocyanate heterocyclization to furnish non-condensed heterocyclic compoundes,Some of the newly synthesized compounds were tested for their antimicrobial activities.

  7. Characterization of antimicrobial peptides from the skin secretions of the Malaysian frogs, Odorrana hosii and Hylarana picturata (Anura:Ranidae).

    Science.gov (United States)

    Conlon, J Michael; Kolodziejek, Jolanta; Nowotny, Norbert; Leprince, Jérôme; Vaudry, Hubert; Coquet, Laurent; Jouenne, Thierry; King, Jay D

    2008-09-01

    Peptidomic analysis of norepinephrine-stimulated skin secretions from Hose's rock frog Odorrana hosii (Boulenger, 1891) led to the isolation of 8 peptides with differential antibacterial activities. Structural characterization demonstrated that the peptides belonged to the esculentin-1 (1 peptide), esculentin-2 (1 peptide), brevinin-1 (2 peptides), brevinin-2 (2 peptides), and nigrocin-2 (2 peptides) families of antimicrobial peptides. Similar analysis of skin secretions from the Malaysian fire frog Hylarana picturata (Boulenger, 1920) led to the isolation and characterization of peptides belonging to the brevinin-1 (2 peptides), brevinin-2 (5 peptides), and temporin (1 peptide) families. The differences in antimicrobial activities of paralogous peptides provide insight into structure-activity relationships, emphasizing the importance of cationicity in determining potency. The substitution Lys11-->Gln in brevinin-1HSa (FLPAVLRVAAKIVPTVFCAISKKC) from O. hosii abolishes growth inhibitory activity against Escherichia coli but has no effect on the high potency (MIC = 8 microg/ml) against Staphylococcus aureus. In contrast, the substitution (Gly4-->Asp) in brevinin-2PTb (GFKGAFKNVMFGIAKSAGKSALNALACKIDKSC) from H. picturata reduces activity against both E. coli and S. aureus. Cladistic analysis based upon the amino acid sequences of the brevinin-2 peptides from Asian frogs provides evidence for sister taxon relationships between O. hosii and O. livida and between H. picturata and H. güntheri. PMID:18621071

  8. Using adjuvants and environmental factors to modulate the activity of antimicrobial peptides.

    Science.gov (United States)

    Walkenhorst, William F

    2016-05-01

    The increase in antibiotic resistant and multi-drug resistant bacterial infections has serious implications for the future of health care. The difficulty in finding both new microbial targets and new drugs against existing targets adds to the concern. The use of combination and adjuvant therapies are potential strategies to counter this threat. Antimicrobial peptides (AMPs) are a promising class of antibiotics (ABs), particularly for topical and surface applications. Efforts have been directed toward a number of strategies, including the use of conventional ABs combined with AMPs, and the use of potentiating agents to increase the performance of AMPs. This review focuses on combination strategies such as adjuvants and the manipulation of environmental variables to improve the efficacy of AMPs as potential therapeutic agents. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. PMID:26751595

  9. Effect of BMAP-28 antimicrobial peptides on Leishmania major promastigote and amastigote growth

    DEFF Research Database (Denmark)

    Lynn, Miriam A.; Kindrachuk, Jason; Marr, Alexandra K.;

    2011-01-01

    Background: Protozoan parasites, such as Leishmania, still pose an enormous public health problem in many countries throughout the world. Current measures are outdated and have some associated drug resistance, prompting the search into novel therapies. Several innovative approaches are under...... of the cathelicidin family of HDPs have demonstrated significant antimicrobial activities against various parasites including Leishmania. The cathelicidin bovine myeloid antimicrobial peptide 28 (BMAP-28) has broad antimicrobial activities and confers protection in animal models of bacterial infection or sepsis. We...... tested the effectiveness of the use of BMAP-28 and two of its isomers the D-amino acid form (D-BMAP-28) and the retro-inverso form (RI-BMAP-28), as anti-leishmanial agents against the promastigote and amastigote intracellular Leishmania major lifecycle stages. Methodology/Principal Findings: An MTS...

  10. Structural determinants of host defense peptides for antimicrobial activity and target cell selectivity.

    Science.gov (United States)

    Takahashi, Daisuke; Shukla, Sanjeev K; Prakash, Om; Zhang, Guolong

    2010-09-01

    Antimicrobial host defense peptides (HDPs) are a critical component of the innate immunity with microbicidal, endotoxin-neutralizing, and immunostimulatory properties. HDPs kill bacteria primarily through non-specific membrane lysis, therefore with a less likelihood of provoking resistance. Extensive structure-activity relationship studies with a number of HDPs have revealed that net charge, amphipathicity, hydrophobicity, and structural propensity are among the most important physicochemical and structural parameters that dictate their ability to interact with and disrupt membranes. A delicate balance among these factors, rather than a mere alteration of a single factor, is critically important for HDPs to ensure the antimicrobial potency and target cell selectivity. With a better understanding of the structural determinants of HDPs for their membrane-lytic activities, it is expected that novel HDP-based antimicrobials with minimum toxicity to eukaryotic cells can be developed for resistant infections, which have become a global public health crisis.

  11. Pimecrolimus Enhances TLR2/6-Induced Expression of Antimicrobial Peptides in Keratinocytes

    OpenAIRE

    Büchau, Amanda S.; Schauber, Jürgen; Hultsch, Thomas; Stuetz, Anton; Richard L Gallo

    2008-01-01

    Calcineurin inhibitors are potent inhibitors of T-cell-receptor mediated activation of the adaptive immune system. The effects of this class of drug on the innate immune response system are not known. Keratinocytes are essential to innate immunity in skin and rely on toll-like receptors (TLRs) and antimicrobial peptides to appropriately recognize and respond to injury or microbes. In this study we examined the response of cultured human keratinocytes to pimecrolimus. We observed that pimecrol...

  12. A Salmonella protein that is required for resistance to antimicrobial peptides and transport of potassium.

    OpenAIRE

    Parra-Lopez, C; Lin, R; Aspedon, A; Groisman, E A

    1994-01-01

    The ability of invading pathogens to proliferate within host tissues requires the capacity to resist the killing effects of a wide variety of host defense molecules. sap mutants of the facultative intracellular parasite Salmonella typhimurium exhibit hypersensitivity to antimicrobial peptides, cannot survive within macrophages in vitro and are attenuated for mouse virulence in vivo. We conducted a molecular genetic analysis of the sapG locus and showed that it encodes a product that is 99% id...

  13. Safety Study of an Antimicrobial Peptide Lactocin 160, Produced by the Vaginal Lactobacillus rhamnosus

    OpenAIRE

    Dover, Sara E.; Alla A. Aroutcheva; S. Faro; Chikindas, Michael L.

    2007-01-01

    Objective. To evaluate the safety of the antimicrobial peptide, lactocin 160. Methods. Lactocin 160, a product of vaginal probiotic Lactobacillus rhamnosus 160 was evaluated for toxicity and irritation. An in vitro human organotypic vaginal-ectocervical tissue model (EpiVaginal) was employed for the safety testing by determining the exposure time to reduce tissue viability to 50% (ET-50). Hemolytic activity of lactocin160 was tested using 8% of human erythrocyte suspens...

  14. Nanoparticle-mediated delivery of the antimicrobial peptide plectasin against Staphylococcus aureus in infected epithelial cells

    DEFF Research Database (Denmark)

    Water, Jorrit Jeroen; Smart, Simon; Franzyk, Henrik;

    2015-01-01

    improved efficacy as compared to non-encapsulated plectasin, while the eukaryotic cell viability was unaffected at the assayed concentrations. Further, the subcellular localization of the nanoparticles was assessed in different relevant cell lines. The nanoparticles were distributed in punctuate patterns......A number of pathogenic bacterial strains, such as Staphylococcus aureus, are difficult to kill with conventional antibiotics due to intracellular persistence in host airway epithelium. Designing drug delivery systems to deliver potent antimicrobial peptides (AMPs) intracellularly to the airway...

  15. Rhizosecretion of The Recombinant Antimicrobial Peptide Ranalexin from Transgenic Tobacco Hairy Roots

    OpenAIRE

    Rasha Abou Aleinein; Holger Schäfer; Michael Wink

    2015-01-01

    Rhizosecretion of functional recombinant proteins from in vitro cultured roots into the hydroponic medium offers an attractive technology to simplify down-stream purification procedures. Aim of the present study was the production and secretion of the antimicrobial peptide (AMP) ranalexin from Nicotiana tabacum hairy roots which were transformed by agroinfection. A His-tagged ranalexin was expressed under the control of CaMV 35S promoter and directed into the plant secretion pathway by fusing...

  16. Immobilization of antimicrobial peptide IG-25 onto fluoropolymers via fluorous interactions and click chemistry

    OpenAIRE

    Santos, Catherine M.; Kumar, Amit; Kolar, Satya S.; Contreras-Caceres, Rafael; McDermott, Alison; Cai, Chengzhi

    2013-01-01

    We report a practical method for biofunctionalization of fluoropolymers based on non-covalent, fluorous interactions and click chemistry which allows incorporation of biomolecules under physiological solutions. We demonstrate the method by immobilization of an antimicrobial peptide (AMP) on fluorous thin films and fluorosilicone contact lens. The fluorous surfaces were dip-coated with fluorous-tagged oligo(ethylene) chain terminated with a reactive group, such as an alkynyl group. This simple...

  17. Antimicrobial Peptides as Potential Alternatives to Antibiotics in Food Animal Industry.

    Science.gov (United States)

    Wang, Shuai; Zeng, Xiangfang; Yang, Qing; Qiao, Shiyan

    2016-01-01

    Over the last decade, the rapid emergence of multidrug-resistant pathogens has become a global concern, which has prompted the search for alternative antibacterial agents for use in food animals. Antimicrobial peptides (AMPs), produced by bacteria, insects, amphibians and mammals, as well as by chemical synthesis, are possible candidates for the design of new antimicrobial agents because of their natural antimicrobial properties and a low propensity for development of resistance by microorganisms. This manuscript reviews the current knowledge of the basic biology of AMPs and their applications in non-ruminant nutrition. Antimicrobial peptides not only have broad-spectrum activity against bacteria, fungi, and viruses but also have the ability to bypass the common resistance mechanisms that are placing standard antibiotics in jeopardy. In addition, AMPs have beneficial effects on growth performance, nutrient digestibility, intestinal morphology and gut microbiota in pigs and broilers. Therefore, AMPs have good potential as suitable alternatives to conventional antibiotics used in swine and poultry industries. PMID:27153059

  18. Antimicrobial Peptides as Potential Alternatives to Antibiotics in Food Animal Industry

    Directory of Open Access Journals (Sweden)

    Shuai Wang

    2016-05-01

    Full Text Available Over the last decade, the rapid emergence of multidrug-resistant pathogens has become a global concern, which has prompted the search for alternative antibacterial agents for use in food animals. Antimicrobial peptides (AMPs, produced by bacteria, insects, amphibians and mammals, as well as by chemical synthesis, are possible candidates for the design of new antimicrobial agents because of their natural antimicrobial properties and a low propensity for development of resistance by microorganisms. This manuscript reviews the current knowledge of the basic biology of AMPs and their applications in non-ruminant nutrition. Antimicrobial peptides not only have broad-spectrum activity against bacteria, fungi, and viruses but also have the ability to bypass the common resistance mechanisms that are placing standard antibiotics in jeopardy. In addition, AMPs have beneficial effects on growth performance, nutrient digestibility, intestinal morphology and gut microbiota in pigs and broilers. Therefore, AMPs have good potential as suitable alternatives to conventional antibiotics used in swine and poultry industries.

  19. New antimicrobial peptides against foodborne pathogens: From in silico design to experimental evidence.

    Science.gov (United States)

    Palmieri, Gianna; Balestrieri, Marco; Proroga, Yolande T R; Falcigno, Lucia; Facchiano, Angelo; Riccio, Alessia; Capuano, Federico; Marrone, Raffaele; Neglia, Gianluca; Anastasio, Aniello

    2016-11-15

    Recently there has been growing interest in the discovery of new antimicrobial agents to increase safety and shelf-life of food products. Here, we developed an innovative approach by introducing the concept that mitochondrial targeting peptides (MTP) can interact and disrupt bacterial membranes, acting as antimicrobial agents. As proof-of-principle, we used a multidisciplinary strategy by combining in silico predictions, docking simulations and antimicrobial assays, to identify two peptides, MTP1 and MTP2, which were structurally and functionally characterized. Both compounds appeared effective against Listeria monocytogenes, one of the most important foodborne pathogens. Specifically, a significant bactericidal activity was evidenced with EC50 values of 16.8±1.2μM for MTP1 and 109±7.0μM for MTP2. Finally, NMR structure determinations suggested that MTP1 would be oriented into the membrane bilayer, while the molecular shape of MTP2 could indicate porin-mediated antimicrobial mechanisms, as predicted using molecular docking analysis. Therefore, MTPs represent alternative sources to design new potential bio-preservatives. PMID:27283665

  20. Increased survival of experimentally evolved antimicrobial peptide-resistant Staphylococcus aureus in an animal host.

    Science.gov (United States)

    Dobson, Adam J; Purves, Joanne; Rolff, Jens

    2014-09-01

    Antimicrobial peptides (AMPs) have been proposed as new class of antimicrobial drugs, following the increasing prevalence of bacteria resistant to antibiotics. Synthetic AMPs are functional analogues of highly evolutionarily conserved immune effectors in animals and plants, produced in response to microbial infection. Therefore, the proposed therapeutic use of AMPs bears the risk of 'arming the enemy': bacteria that evolve resistance to AMPs may be cross-resistant to immune effectors (AMPs) in their hosts. We used a panel of populations of Staphylococcus aureus that were experimentally selected for resistance to a suite of individual AMPs and antibiotics to investigate the 'arming the enemy' hypothesis. We tested whether the selected strains showed higher survival in an insect model (Tenebrio molitor) and cross-resistance against other antimicrobials in vitro. A population selected for resistance to the antimicrobial peptide iseganan showed increased in vivo survival, but was not more virulent. We suggest that increased survival of AMP-resistant bacteria almost certainly poses problems to immune-compromised hosts.

  1. Marine Antimicrobial Peptides: Nature Provides Templates for the Design of Novel Compounds against Pathogenic Bacteria

    Science.gov (United States)

    Falanga, Annarita; Lombardi, Lucia; Franci, Gianluigi; Vitiello, Mariateresa; Iovene, Maria Rosaria; Morelli, Giancarlo; Galdiero, Massimiliano; Galdiero, Stefania

    2016-01-01

    The discovery of antibiotics for the treatment of bacterial infections brought the idea that bacteria would no longer endanger human health. However, bacterial diseases still represent a worldwide treat. The ability of microorganisms to develop resistance, together with the indiscriminate use of antibiotics, is mainly responsible for this situation; thus, resistance has compelled the scientific community to search for novel therapeutics. In this scenario, antimicrobial peptides (AMPs) provide a promising strategy against a wide array of pathogenic microorganisms, being able to act directly as antimicrobial agents but also being important regulators of the innate immune system. This review is an attempt to explore marine AMPs as a rich source of molecules with antimicrobial activity. In fact, the sea is poorly explored in terms of AMPs, but it represents a resource with plentiful antibacterial agents performing their role in a harsh environment. For the application of AMPs in the medical field limitations correlated to their peptide nature, their inactivation by environmental pH, presence of salts, proteases, or other components have to be solved. Thus, these peptides may act as templates for the design of more potent and less toxic compounds. PMID:27213366

  2. Enhanced membrane pore formation by multimeric/oligomeric antimicrobial peptides.

    Science.gov (United States)

    Arnusch, Christopher J; Branderhorst, Hilbert; de Kruijff, Ben; Liskamp, Rob M J; Breukink, Eefjan; Pieters, Roland J

    2007-11-20

    The pore-forming antibacterial peptide magainin 2 was made divalent, tetravalent, and octavalent via a copper(I)-mediated 1-3 dipolar cycloaddition reaction ("click" chemistry). This series of pore-forming compounds was tested in vitro for their ability to form pores in large unilamillar vesicles (LUVs). A large increase in the pore-forming capability was especially observed with the tetravalent and octavalent magainin compounds in the LUVs consisting of DOPC, and the octavalent magainin compound showed a marked increase with the DOPC/DOPG LUVs. Activity was observed in the low nanomolar range for these compounds. PMID:17944489

  3. Antimicrobial Properties of Newly Synthesized Derivatives of Coumarine

    Directory of Open Access Journals (Sweden)

    S. Govori

    2010-01-01

    Full Text Available Problem statement: Coumarins are well known for their biological activity. On the basis of that we have synthesized some new derivatives of coumarine and investigated their antimicrobial properties. Approach: 4-Heteroaryl-coumarin-3-carbaldehydes 4(a-d are synthesized by condensation of 4-chloro-coumarin-3-carbaldehydes 2 and corresponding heterorylamines 3(a-d under reflux reaction conditions. Antimicrobial properties of new coumarins 4(a-d are investigated and results are submitted for their activities against Staphylococcus aureus, Escherichia coli, Hafnia alvei, Pseudomonas aeruginosa and Enterobacter cloacae. Applying the Agar disc diffusion technique we measured diameters of the inhibition zone around discs which are previously wetted with N, N-DMF solution of compounds, 1, 3 and 5 mg L−1. Results: The inhibition zone depends from concentrations and also from sort of bacteria. The inhibition zone differ from 0 to 30mm. Two sort of bacteria, Hafnia alvei and Pseudomonas aeruginosa, are resistant to these new synthesized compounds. Conclusion: From results we may conclude that these derivates showed moderate to high activity against Staphylococcus aureus, Escherichia coli and Enterobacter cloaco. Compounds 4(a-d are more active against Staphylococcus aureus, E.coli and Enterobacter cloaco. Compounds 4(a-d are not active against Hafnia alvei and Pseudomonas aeruginosa.

  4. SYNTHESIS AND ANTIMICROBIAL ACTIVITIES OF NEW PYRAZOLOPYRIDAZINE DERIVATIVES

    Directory of Open Access Journals (Sweden)

    Mahfuz Alam

    2015-03-01

    Full Text Available Several new pryrazolo-pyridazine derivatives (4a-h were synthesized through multi-step synthesis and evaluated for their antimicrobial activities. In the first step, 6-phenyl-2,3,4,5-tetrahydropyridazin-3-one (2 was prepared by reacting 4-(4-chlorophenyl-4-oxobutanoic acid (1 with hydrazine hydrate. Then, aryl-aldehydes were reacted with 2 to furnish pyridazinone derivatives (3a-g. Finally, pyridazinones (3a-h were reacted with hydrazine hydrate to furnish the title compounds (4a-h. The newly synthesized compounds were evaluated for their in vitro antibacterial and antifungal activities against six microbial strains. Compounds 4d, 4e and 4f exhibited significant antibacterial action, whereas compounds 4c and 4d showed potential antifungal activity. Compound 4d, 5-(4-Chlorophenyl-3-(4-fluorophenyl-3,3a,4,7-tetrahydro-2H-pyrazolo[3,4- ]pyridazine, emerged as lead compound having broad spectrum of antimicrobial action.

  5. Phylloseptin-PBa—A Novel Broad-Spectrum Antimicrobial Peptide from the Skin Secretion of the Peruvian Purple-Sided Leaf Frog (Phyllomedusa Baltea Which Exhibits Cancer Cell Cytotoxicity

    Directory of Open Access Journals (Sweden)

    Yuantai Wan

    2015-12-01

    Full Text Available Antimicrobial peptides from amphibian skin secretion display remarkable broad-spectrum antimicrobial activity and are thus promising for the discovery of new antibiotics. In this study, we report a novel peptide belonging to the phylloseptin family of antimicrobial peptides, from the skin secretion of the purple-sided leaf frog, Phyllomedusa baltea, which was named Phylloseptin-PBa. Degenerate primers complementary to putative signal peptide sites of frog skin peptide precursor-encoding cDNAs were designed to interrogate a skin secretion-derived cDNA library from this frog. Subsequently, the peptide was isolated and identified using reverse phase HPLC and MS/MS fragmentation. The synthetic replicate was demonstrated to have activity against S. aureus, E. coli and C. albicans at concentrations of 8, 128 and 8 mg/L, respectively. In addition, it exhibited anti-proliferative activity against the human cancer cell lines, H460, PC3 and U251MG, but was less active against a normal human cell line (HMEC. Furthermore, a haemolysis assay was performed to assess mammalian cell cytotoxicity of Phylloseptin-PBa. This peptide contained a large proportion of α-helical domain, which may explain its antimicrobial and anticancer activities.

  6. Food-Derived Bioactive Peptides on Inflammation and Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Subhadeep Chakrabarti

    2014-01-01

    Full Text Available Chronic diseases such as atherosclerosis and cancer are now the leading causes of morbidity and mortality worldwide. Inflammatory processes and oxidative stress underlie the pathogenesis of these pathological conditions. Bioactive peptides derived from food proteins have been evaluated for various beneficial effects, including anti-inflammatory and antioxidant properties. In this review, we summarize the roles of various food-derived bioactive peptides in inflammation and oxidative stress and discuss the potential benefits and limitations of using these compounds against the burden of chronic diseases.

  7. Combating multidrug-resistant Gram-negative bacteria with structurally nanoengineered antimicrobial peptide polymers.

    Science.gov (United States)

    Lam, Shu J; O'Brien-Simpson, Neil M; Pantarat, Namfon; Sulistio, Adrian; Wong, Edgar H H; Chen, Yu-Yen; Lenzo, Jason C; Holden, James A; Blencowe, Anton; Reynolds, Eric C; Qiao, Greg G

    2016-01-01

    With the recent emergence of reports on resistant Gram-negative 'superbugs', infections caused by multidrug-resistant (MDR) Gram-negative bacteria have been named as one of the most urgent global health threats due to the lack of effective and biocompatible drugs. Here, we show that a class of antimicrobial agents, termed 'structurally nanoengineered antimicrobial peptide polymers' (SNAPPs) exhibit sub-μM activity against all Gram-negative bacteria tested, including ESKAPE and colistin-resistant and MDR (CMDR) pathogens, while demonstrating low toxicity. SNAPPs are highly effective in combating CMDR Acinetobacter baumannii infections in vivo, the first example of a synthetic antimicrobial polymer with CMDR Gram-negative pathogen efficacy. Furthermore, we did not observe any resistance acquisition by A. baumannii (including the CMDR strain) to SNAPPs. Comprehensive analyses using a range of microscopy and (bio)assay techniques revealed that the antimicrobial activity of SNAPPs proceeds via a multimodal mechanism of bacterial cell death by outer membrane destabilization, unregulated ion movement across the cytoplasmic membrane and induction of the apoptotic-like death pathway, possibly accounting for why we did not observe resistance to SNAPPs in CMDR bacteria. Overall, SNAPPs show great promise as low-cost and effective antimicrobial agents and may represent a weapon in combating the growing threat of MDR Gram-negative bacteria. PMID:27617798

  8. The Alzheimer's disease-associated amyloid beta-protein is an antimicrobial peptide.

    Directory of Open Access Journals (Sweden)

    Stephanie J Soscia

    Full Text Available BACKGROUND: The amyloid beta-protein (Abeta is believed to be the key mediator of Alzheimer's disease (AD pathology. Abeta is most often characterized as an incidental catabolic byproduct that lacks a normal physiological role. However, Abeta has been shown to be a specific ligand for a number of different receptors and other molecules, transported by complex trafficking pathways, modulated in response to a variety of environmental stressors, and able to induce pro-inflammatory activities. METHODOLOGY/PRINCIPAL FINDINGS: Here, we provide data supporting an in vivo function for Abeta as an antimicrobial peptide (AMP. Experiments used established in vitro assays to compare antimicrobial activities of Abeta and LL-37, an archetypical human AMP. Findings reveal that Abeta exerts antimicrobial activity against eight common and clinically relevant microorganisms with a potency equivalent to, and in some cases greater than, LL-37. Furthermore, we show that AD whole brain homogenates have significantly higher antimicrobial activity than aged matched non-AD samples and that AMP action correlates with tissue Abeta levels. Consistent with Abeta-mediated activity, the increased antimicrobial action was ablated by immunodepletion of AD brain homogenates with anti-Abeta antibodies. CONCLUSIONS/SIGNIFICANCE: Our findings suggest Abeta is a hitherto unrecognized AMP that may normally function in the innate immune system. This finding stands in stark contrast to current models of Abeta-mediated pathology and has important implications for ongoing and future AD treatment strategies.

  9. SCREENING OF ANTIMICROBIAL ACTIVITY AND GENES CODING POLYKETIDE SYNTHETASE AND NONRIBOSOMAL PEPTIDE SYNTHETASE OF ACTINOMYCETE ISOLATES

    Directory of Open Access Journals (Sweden)

    Silvia Kovácsová

    2013-12-01

    Full Text Available The aim of this study was to observe antimicrobial activity using agar plate diffusion method and screening genes coding polyketide synthetase (PKS-I and nonribosomal peptide synthetase (NRPS from actinomycetes. A total of 105 actinomycete strains were isolated from arable soil. Antimicrobial activity was demonstrated at 54 strains against at least 1 of total 12 indicator organisms. Antifungal properties were recorded more often than antibacterial properties. The presence of PKS-I and NRPS genes were founded at 61 of total 105 strains. The number of strains with mentioned biosynthetic enzyme gene fragments matching the anticipated length were 19 (18% and 50 (47% respectively. Overall, five actinomycete strains carried all the biosynthetical genes, yet no antimicrobial activity was found against any of tested pathogens. On the other hand, twenty-one strains showed antimicrobial activity even though we were not able to amplify any of the PKS or NRPS genes from them. Combination of the two methods showed broad-spectrum antimicrobial activity of actinomycetes isolated from arable soil, which indicate that actinomycetes are valuable reservoirs of novel bioactive compounds.

  10. Role of the LytSR two-component regulatory system in adaptation to cationic antimicrobial peptides in Staphylococcus aureus.

    Science.gov (United States)

    Yang, Soo-Jin; Xiong, Yan Q; Yeaman, Michael R; Bayles, Kenneth W; Abdelhady, Wessam; Bayer, Arnold S

    2013-08-01

    Many host defense cationic antimicrobial peptides (HDPs) perturb the staphylococcal cell membrane (CM) and alter transmembrane potential (ΔΨ) as key parts of their lethal mechanism. Thus, a sense-response system for detecting and mediating adaptive responses to such stresses could impact organism survival; the Staphylococcus aureus LytSR two-component regulatory system (TCRS) may serve as such a ΔΨ sensor. One well-known target of this system is the lrgAB operon, which, along with the related cidABC operon, has been shown to be a regulator in the control of programmed cell death and lysis. We used an isogenic set of S. aureus strains: (i) UAMS-1, (ii) its isogenic ΔlytS and ΔlrgAB mutants, and (iii) plasmid-complemented ΔlytSR and ΔlrgAB mutants. The ΔlytS strain displayed significantly increased in vitro susceptibilities to all HDPs tested (neutrophil-derived human neutrophil peptide 1 [hNP-1], platelet-derived thrombin-induced platelet microbicidal proteins [tPMPs], and the tPMP-mimetic peptide RP-1), as well as to calcium-daptomycin (DAP), a cationic antimicrobial peptide (CAP). In contrast, the ΔlrgAB strain exhibited no significant changes in susceptibilities to these cationic peptides, indicating that although lytSR positively regulates transcription of lrgAB, increased HDP/CAP susceptibilities in the ΔlytS mutant were lrgAB independent. Further, parental UAMS-1 (but not the ΔlytS mutant) became more resistant to hNP-1 and DAP following pretreatment with carbonyl cyanide m-chlorophenylhydrazone (CCCP) (a CM-depolarizing agent). Of note, lytSR-dependent survival against CAP/HDP killing was not associated with changes in either surface positive charge, expression of mprF and dlt, or CM fluidity. The ΔlytS strain (but not the ΔlrgAB mutant) displayed a significant reduction in target tissue survival in an endocarditis model during DAP treatment. Collectively, these results suggest that the lytSR TCRS plays an important role in adaptive responses of

  11. How the antimicrobial peptides destroy bacteria cell membrane: Translocations vs. membrane buckling

    Science.gov (United States)

    Golubovic, Leonardo; Gao, Lianghui; Chen, Licui; Fang, Weihai

    2012-02-01

    In this study, coarse grained Dissipative Particle Dynamics simulation with implementation of electrostatic interactions is developed in constant pressure and surface tension ensemble to elucidate how the antimicrobial peptide molecules affect bilayer cell membrane structure and kill bacteria. We find that peptides with different chemical-physical properties exhibit different membrane obstructing mechanisms. Peptide molecules can destroy vital functions of the affected bacteria by translocating across their membranes via worm-holes, or by associating with membrane lipids to form hydrophilic cores trapped inside the hydrophobic domain of the membranes. In the latter scenario, the affected membranes are strongly corrugated (buckled) in accord with very recent experimental observations [G. E. Fantner et al., Nat. Nanotech., 5 (2010), pp. 280-285].

  12. Chimeric Peptides as Implant Functionalization Agents for Titanium Alloy Implants with Antimicrobial Properties

    Science.gov (United States)

    Yucesoy, Deniz T.; Hnilova, Marketa; Boone, Kyle; Arnold, Paul M.; Snead, Malcolm L.; Tamerler, Candan

    2015-04-01

    Implant-associated infections can have severe effects on the longevity of implant devices and they also represent a major cause of implant failures. Treating these infections associated with implants by antibiotics is not always an effective strategy due to poor penetration rates of antibiotics into biofilms. Additionally, emerging antibiotic resistance poses serious concerns. There is an urge to develop effective antibacterial surfaces that prevent bacterial adhesion and proliferation. A novel class of bacterial therapeutic agents, known as antimicrobial peptides (AMPs), are receiving increasing attention as an unconventional option to treat septic infection, partly due to their capacity to stimulate innate immune responses and for the difficulty of microorganisms to develop resistance towards them. While host and bacterial cells compete in determining the ultimate fate of the implant, functionalization of implant surfaces with AMPs can shift the balance and prevent implant infections. In the present study, we developed a novel chimeric peptide to functionalize the implant material surface. The chimeric peptide simultaneously presents two functionalities, with one domain binding to a titanium alloy implant surface through a titanium-binding domain while the other domain displays an antimicrobial property. This approach gains strength through control over the bio-material interfaces, a property built upon molecular recognition and self-assembly through a titanium alloy binding domain in the chimeric peptide. The efficiency of chimeric peptide both in-solution and absorbed onto titanium alloy surface was evaluated in vitro against three common human host infectious bacteria, Streptococcus mutans, Staphylococcus epidermidis, and Escherichia coli. In biological interactions such as occur on implants, it is the surface and the interface that dictate the ultimate outcome. Controlling the implant surface by creating an interface composed chimeric peptides may therefore

  13. Structural and Antimicrobial Features of Peptides Related to Myticin C, a Special Defense Molecule from the Mediterranean Mussel Mytilus galloprovincialis.

    Science.gov (United States)

    Domeneghetti, Stefania; Franzoi, Marco; Damiano, Nunzio; Norante, Rosa; El Halfawy, Nancy M; Mammi, Stefano; Marin, Oriano; Bellanda, Massimo; Venier, Paola

    2015-10-28

    Mussels (Mytilus spp.) have a large repertoire of cysteine-stabilized α,β peptides, and myticin C (MytC) was identified in some hundreds of transcript variants after in vivo immunostimulation. Using a sequence expressed in Italian mussels, we computed the MytC structure and synthesized the mature MytC and related peptide fragments (some of them also prepared in oxidized form) to accurately assess their antibacterial and antifungal activity. Only when tested at pH 5 was the reduced MytC as well as reduced and oxidized fragments including structural β-elements able to inhibit Gram-positive and -negative bacteria (MIC ranges of 4-32 and 8-32 μM, respectively). Such fragments caused selective Escherichia coli killing (MBC of 8-32 μM) but scarcely inhibited two fungal strains. In detail, the antimicrobial β-hairpin MytC[19-40]SOX caused membrane-disrupting effects in E. coli despite its partially ordered conformation in membrane-mimetic environments. In perspective, MytC-derived peptides could be employed to protect acidic mucosal tissues, in cosmetic and food products, and, possibly, as adjuvants in aquaculture.

  14. Peptiderive server: derive peptide inhibitors from protein-protein interactions.

    Science.gov (United States)

    Sedan, Yuval; Marcu, Orly; Lyskov, Sergey; Schueler-Furman, Ora

    2016-07-01

    The Rosetta Peptiderive protocol identifies, in a given structure of a protein-protein interaction, the linear polypeptide segment suggested to contribute most to binding energy. Interactions that feature a 'hot segment', a linear peptide with significant binding energy compared to that of the complex, may be amenable for inhibition and the peptide sequence and structure derived from the interaction provide a starting point for rational drug design. Here we present a web server for Peptiderive, which is incorporated within the ROSIE web interface for Rosetta protocols. A new feature of the protocol also evaluates whether derived peptides are good candidates for cyclization. Fast computation times and clear visualization allow users to quickly assess the interaction of interest. The Peptiderive server is available for free use at http://rosie.rosettacommons.org/peptiderive. PMID:27141963

  15. Antimicrobial action from a novel porphyrin derivative in photodynamic antimicrobial chemotherapy in vitro.

    Science.gov (United States)

    Latief, Miftahul Akhyar; Chikama, Taiichiro; Shibasaki, Momoko; Sasaki, Takaaki; Ko, Ji-Ae; Kiuchi, Yoshiaki; Sakaguchi, Takemasa; Obana, Akira

    2015-01-01

    Efforts to identify improved treatments for corneal infection include the development of photodynamic antimicrobial chemotherapy (PACT). We evaluated the antimicrobial effect of PACT with a novel porphyrin derivative, TONS 504, and a novel light system on methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). Bacteria were irradiated with a light-emitting diode (LED) at energies of 10, 20, or 30 J/cm(2) in the presence of various concentrations of TONS 504. Bacterial viability was assessed at 30 min and 24 h after irradiation by determination of colony formation on agar plates. PACT inhibited the growth of both MSSA and MRSA as early as 30 min after light exposure. Complete inhibition of bacterial growth was apparent at 24 h after irradiation at a TONS 504 concentration of 1 mg/L and LED energies of ≥10 J/cm(2) or a TONS 504 concentration of 0.5 mg/L and LED energies of ≥20 J/cm(2) for MSSA, and at a TONS 504 concentration of 10 mg/L and LED energies of ≥10 J/cm(2) or of a TONS 504 concentration of 1 mg/L and LED energies of ≥20 J/cm(2) for MRSA. Bacterial growth was unaffected by TONS 504 in the absence of irradiation or by irradiation in the absence of TONS 504. Our results thus demonstrate the antimicrobial efficacy of PACT with TONS 504 and a LED against both MSSA and MRSA in vitro, and they therefore provide a basis for further investigation of this system as a potential treatment for corneal infection.

  16. Antimicrobial peptide incorporated poly(2-hydroxyethyl methacrylate) hydrogels for the prevention of Staphylococcus epidermidis-associated biomaterial infections.

    Science.gov (United States)

    Laverty, Garry; Gorman, Sean P; Gilmore, Brendan F

    2012-07-01

    The effectiveness of the antimicrobial peptide maximin-4, the ultrashort peptide H-Orn-Orn-Trp-Trp-NH(2), and the lipopeptide C(12)-Orn-Orn-Trp-Trp-NH(2) in preventing adherence of pathogens to a candidate biomaterial were tested utilizing both matrix- and immersion-loaded poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogels. Antiadherent properties correlated to both the concentration released and the relative antimicrobial concentrations of each compound against Staphylococcus epidermidis ATCC 35984, at each time point. Immersion-loaded samples containing C(12)-Orn-Orn-Trp-Trp-NH(2) exhibited the lowest adherence profile for all peptides studied over 1, 4, and 24 h. The results outlined in this article show that antimicrobial peptides have the potential to serve as an important weapon against biomaterial associated infections.

  17. Proteolytic activity of Escherichia coli oligopeptidase B against proline-rich antimicrobial peptides

    DEFF Research Database (Denmark)

    Mattiuzzo, Maura; De Gobba, Cristian; Runti, Giulia;

    2014-01-01

    bacterial cells specifically less susceptible to several proline-rich antimicrobial peptides known to penetrate into the bacterial cytosol, and that its level of activity directly correlates with the degree of resistance. We established that E. coli OpdB can efficiently hydrolyze in vitro cationic...... the P1 and P2 positions. These results also indicate that cytosolic peptidases may cause resistance to antimicrobial peptides that have an intracellular mechanism of action, such as the proline-rich peptides, and may contribute to define the substrate specificity of the E. coli OpdB....... antimicrobial peptides up to 30 residues in length, even though they contained several prolines, shortening them to inactive fragments. Two consecutive basic residues are a preferred cleavage site for the peptidase. In the case of a single basic residue, there is no cleavage if proline residues are present in...

  18. Overexpression of Antimicrobial, Anticancer, and Transmembrane Peptides in Escherichia coli through a Calmodulin-Peptide Fusion System.

    Science.gov (United States)

    Ishida, Hiroaki; Nguyen, Leonard T; Gopal, Ramamourthy; Aizawa, Tomoyasu; Vogel, Hans J

    2016-09-01

    In recent years, the increasing number of antibiotic-resistant bacteria has become a serious health concern. Antimicrobial peptides (AMPs) are an important component of the innate immune system of most organisms. A better understanding of their structures and mechanisms of action would lead to the design of more potent and safer AMPs as alternatives for current antibiotics. For detailed investigations, effective recombinant production which allows the facile modification of the amino acid sequence, the introduction of unnatural amino acids, and labeling with stable isotopes for nuclear magnetic resonance (NMR) studies is desired. Several expression strategies have been introduced in previous reports; however, their effectiveness has been limited to a select few AMPs. Here, we have studied calmodulin (CaM) as a more universal carrier protein to express many types of AMPs in E. coli. We have discovered that the unique architecture of CaM, consisting of two independent target binding domains with malleable methionine-rich interaction surfaces, can accommodate numerous amino acid sequences containing basic and hydrophobic residues. This effectively masks the toxic antimicrobial activities of many amphipathic AMPs and protects them from degradation during expression and purification. Here, we demonstrate the expression of various AMPs using a CaM-fusion expression system, including melittin, fowlicidin-1, tritrpticin, indolicidin, puroindoline A peptide, magainin II F5W, lactoferrampin B, MIP3α51-70, and human β-defensin 3 (HBD-3), the latter requiring three disulfide bonds for proper folding. In addition, our approach was extended to the transmembrane domain of the cell adhesion protein l-selectin. We propose the use of the CaM-fusion system as a universal approach to express many cationic amphipathic peptides that are normally toxic and would kill the bacterial host cells. PMID:27502305

  19. Blastocystis Isolate B Exhibits Multiple Modes of Resistance against Antimicrobial Peptide LL-37.

    Science.gov (United States)

    Yason, John Anthony; Ajjampur, Sitara Swarna Rao; Tan, Kevin Shyong Wei

    2016-08-01

    Blastocystis is one of the most common eukaryotic organisms found in humans and many types of animals. Several reports have identified its role in gastrointestinal disorders, although its pathogenicity is yet to be clarified. Blastocystis is transmitted via the fecal-to-oral route and colonizes the large intestines. Epithelial cells lining the intestine secrete antimicrobial peptides (AMPs), including beta-defensins and cathelicidin, as a response to infection. This study explores the effects of host colonic antimicrobial peptides, particularly LL-37, a fragment of cathelicidin, on different Blastocystis subtypes. Blastocystis is composed of several subtypes that have genetic, metabolic, and biological differences. These subtypes also have various outcomes in terms of drug treatment and immune response. In this study, Blastocystis isolates from three different subtypes were found to induce intestinal epithelial cells to secrete LL-37. We also show that among the antimicrobial peptides tested, only LL-37 has broad activity on all the subtypes. LL-37 causes membrane disruption and causes Blastocystis to change shape. Blastocystis subtype 7 (ST7), however, showed relative resistance to LL-37. An isolate, ST7 isolate B (ST7-B), from this subtype releases proteases that can degrade the peptide. It also makes the environment acidic, which causes attenuation of LL-37 activity. The Blastocystis ST7-B isolate was also observed to have a thicker surface coat, which may protect the parasite from direct killing by LL-37. This study determined the effects of LL-37 on different Blastocystis isolates and indicates that AMPs have significant roles in Blastocystis infections. PMID:27217421

  20. The New Antimicrobial Peptide SpHyastatin from the Mud Crab Scylla paramamosain with Multiple Antimicrobial Mechanisms and High Effect on Bacterial Infection

    Science.gov (United States)

    Shan, Zhongguo; Zhu, Kexin; Peng, Hui; Chen, Bei; Liu, Jie; Chen, Fangyi; Ma, Xiaowan; Wang, Shuping; Qiao, Kun; Wang, Kejian

    2016-01-01

    SpHyastatin was first identified as a new cationic antimicrobial peptide in hemocytes of the mud crab Scylla paramamosain. Based on the amino acid sequences deduced, it was predicted that this peptide was composed of two different functional domains, a proline-rich domain (PRD) and a cysteine-rich domain (CRD). The recombinant product of SpHyastatin displayed potent antimicrobial activities against the human pathogen Staphylococcus aureus and the aquatic animal pathogens Aeromonas hydrophila and Pseudomonas fluorescens. Compared with the CRD of SpHyastatin, the PRD presented better antimicrobial and chitin binding activities, but both regions were essential for allowing SpHyastatin complete antimicrobial activity. The binding properties of SpHyastatin to different microbial surface molecules suggested that this might be an initial and crucial step for performing its antimicrobial activities. Evaluated using propidium iodide uptake assays and scanning electron microscopy images, the antimicrobial mechanism of SpHyastatin was found to be prone to disrupt cell membrane integrity. Interestingly, SpHyastatin exerted its role specifically on the surface of S. aureus and Pichia pastoris whereas it directly killed P. fluorescens through simultaneous targeting the membrane and the cytoplasm, indicating that SpHyastatin could use different antimicrobial mechanisms to kill different species of microbes. As expected, the recombinant SpHyastatin increased the survival rate of crabs challenged with Vibrio parahaemolyticus. In addition, SpHyastatin could modulate some V. parahaemolyticus-responsive genes in S. paramamosain. PMID:27493644

  1. Two novel non-cationic defensin-like antimicrobial peptides from haemolymph of the female tick, Amblyomma hebraeum.

    Science.gov (United States)

    Lai, Ren; Lomas, Lee O; Jonczy, Jan; Turner, Philip C; Rees, Huw H

    2004-01-01

    Two non-cationic defensin-like antimicrobial peptides, named Amblyomma defensin peptide 1 and Amblyomma defensin peptide 2, were identified from the hard tick, Amblyomma hebraeum, by a combination of suppression subtractive hybridization for differentially expressed genes and proteomics. cDNA clones encoding each of these two defensin-like antimicrobial peptides were isolated from the differentially expressed cDNA library of the tick synganglia (central nervous system). The preproproteins deduced from the cDNA sequences each have 92 amino acid residues. Amblyomma defensin peptide 2 was purified from the haemolymph of fed female ticks. The purified peptide displayed antibacterial activity against Gram-negative and Gram-positive bacteria. Amblyomma defensin peptide 1 was further identified by protein chip capture combined with SELDI-TOF (surface-enhanced laser desorption/ionization-time-of-flight) MS. By screening for differentially expressed proteins, it was found that the expression of Amblyomma defensin peptide 1 was upregulated during 4 days post-feeding. Our findings firstly provide two defensin-like antimicrobial peptides that are particularly novel in being anionic, together with corresponding cDNA sequences, in hard ticks, and prove that the combination of suppression subtractive hybridization and protein profiling is a powerful method to study differentially expressed proteins, especially for organisms without available genome sequence information. PMID:14705963

  2. The TFPI-2 derived peptide EDC34 improves outcome of gram-negative sepsis.

    Directory of Open Access Journals (Sweden)

    Praveen Papareddy

    Full Text Available Sepsis is characterized by a dysregulated host-pathogen response, leading to high cytokine levels, excessive coagulation and failure to eradicate invasive bacteria. Novel therapeutic strategies that address crucial pathogenetic steps during infection are urgently needed. Here, we describe novel bioactive roles and therapeutic anti-infective potential of the peptide EDC34, derived from the C-terminus of tissue factor pathway inhibitor-2 (TFPI-2. This peptide exerted direct bactericidal effects and boosted activation of the classical complement pathway including formation of antimicrobial C3a, but inhibited bacteria-induced activation of the contact system. Correspondingly, in mouse models of severe Escherichia coli and Pseudomonas aeruginosa infection, treatment with EDC34 reduced bacterial levels and lung damage. In combination with the antibiotic ceftazidime, the peptide significantly prolonged survival and reduced mortality in mice. The peptide's boosting effect on bacterial clearance paired with its inhibiting effect on excessive coagulation makes it a promising therapeutic candidate for invasive Gram-negative infections.

  3. Boswellic acids target the human immune system-modulating antimicrobial peptide LL-37.

    Science.gov (United States)

    Henkel, Arne; Tausch, Lars; Pillong, Max; Jauch, Johann; Karas, Michael; Schneider, Gisbert; Werz, Oliver

    2015-12-01

    The antimicrobial peptide LL-37 is the sole member of the human cathelicidin family with immune system-modulating properties and roles in autoimmune disease development. Small molecules able to interact with LL-37 and to modulate its functions have not been described yet. Boswellic acids (BAs) are pentacyclic triterpene acids that are bioactive principles of frankincense extracts used as anti-inflammatory remedies. Although various anti-inflammatory modes of action have been proposed for BAs, the pharmacological profile of these compounds is still incompletely understood. Here, we describe the identification of human LL-37 as functional target of BAs. In unbiased target fishing experiments using immobilized BAs as bait and human neutrophils as target source, LL-37 was identified as binding partner assisted by MALDI-TOF mass spectrometry. Thermal stability experiments using circular dichroism spectroscopy confirm direct interaction between BAs and LL-37. Of interest, this binding of BAs resulted in an inhibition of the functionality of LL-37. Thus, the LPS-neutralizing properties of isolated LL-37 were inhibited by 3-O-acetyl-β-BA (Aβ-BA) and 3-O-acetyl-11-keto-β-BA (AKβ-BA) in a cell-free limulus amoebocyte lysate assay with EC50=0.2 and 0.8 μM, respectively. Also, LL-37 activity was inhibited by these BAs in LL-37-enriched supernatants of stimulated neutrophils or human plasma derived from stimulated human whole blood. Together, we reveal BAs as inhibitors of LL-37, which might be a relevant mechanism underlying the anti-inflammatory properties of BAs and suggests BAs as suitable chemical tools or potential agents for intervention with LL-37 and related disorders. PMID:26361729

  4. iTRAQ-Based Quantitative Proteomic Analysis of the Antimicrobial Mechanism of Peptide F1 against Escherichia coli.

    Science.gov (United States)

    Miao, Jianyin; Chen, Feilong; Duan, Shan; Gao, Xiangyang; Liu, Guo; Chen, Yunjiao; Dixon, William; Xiao, Hang; Cao, Yong

    2015-08-19

    Antimicrobial peptides have received increasing attention in the agricultural and food industries due to their potential to control pathogens. However, to facilitate the development of novel peptide-based antimicrobial agents, details regarding the molecular mechanisms of these peptides need to be elucidated. The aim of this study was to investigate the antimicrobial mechanism of peptide F1, a bacteriocin found in Tibetan kefir, against Escherichia coli at protein levels using iTRAQ-based quantitative proteomic analysis. In response to treatment with peptide F1, 31 of the 280 identified proteins in E. coli showed alterations in their expression, including 10 down-regulated proteins and 21 up-regulated proteins. These 31 proteins all possess different molecular functions and are involved in different molecular pathways, as is evident in referencing the Kyoto Encyclopedia of Genes and Genomes pathways. Specifically, pathways that were significantly altered in E. coli in response to peptide F1 treatment include the tricarboxylic acid cycle, oxidative phosphorylation, glycerophospholipid metabolism, and the cell cycle-caulobacter pathways, which was also associated with inhibition of the cell growth, induction of morphological changes, and cell death. The results provide novel insights into the molecular mechanisms of antimicrobial peptides.

  5. Position-Dependent Influence of the Three Trp Residues on the Membrane Activity of the Antimicrobial Peptide, Tritrpticin

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    Mauricio Arias

    2014-11-01

    Full Text Available Antimicrobial peptides (AMPs constitute promising candidates for the development of new antibiotics. Among the ever-expanding family of AMPs, tritrpticin has strong antimicrobial activity against a broad range of pathogens. This 13-residue peptide has an unusual amino acid sequence that is almost symmetrical and features three central Trp residues with two Arg residues near each end of the peptide. In this work, the role of the three sequential Trp residues in tritrpticin was studied in a systematic fashion by making a series of synthetic peptides with single-, double- and triple-Trp substitutions to Tyr or Ala. 1H NMR and fluorescence spectroscopy demonstrated the ability of all of the tritrpticin-analog peptides to interact with negatively-charged membranes. Consequently, most tritrpticin analogs exhibited the ability to permeabilize synthetic ePC:ePG (egg-yolk phosphatidylcholine (ePC, egg-yolk phosphatidylglycerol (ePG vesicles and live Escherichia coli bacteria. The membrane perturbation characteristics were highly dependent on the location of the Trp residue substitution, with Trp6 being the most important residue and Trp8 the least. The membrane permeabilization activity of the peptides in synthetic and biological membranes was directly correlated with the antimicrobial potency of the peptides against E. coli. These results contribute to the understanding of the role of each of the three Trp residues to the antimicrobial activity of tritrpticin.

  6. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice.

    Science.gov (United States)

    Shi, Wei; Li, Caiyun; Li, Man; Zong, Xicui; Han, Dongju; Chen, Yuqing

    2016-06-01

    Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metabolism, and nucleic acid, and protein synthesis. The antibacterial effects arose from its ability to interact with the bacterial cell wall and disrupt the cytoplasmic membrane by making holes and channels, resulting in the leakage of the cytoplasmic content. Additionally, melittin is able to permeabilize bacterial membranes and reach the cytoplasm, indicating that there are multiple mechanisms of antimicrobial action. DNA/RNA binding assay suggests that melittin may inhibit macromolecular biosynthesis by binding intracellular targets, such as DNA or RNA, and that those two modes eventually lead to bacterial cell death. Melittin can inhibit X. oryzae pv. oryzae from spreading, alleviating the disease symptoms, which indicated that melittin may have potential applications in plant protection. PMID:26948237

  7. Influence of Amphibian Antimicrobial Peptides and Short Lipopeptides on Bacterial Biofilms Formed on Contact Lenses

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    Magdalena Maciejewska

    2016-10-01

    Full Text Available The widespread use of contact lenses is associated with several complications, including ocular biofilm-related infections. They are very difficult to manage with standard antimicrobial therapies, because bacterial growth in a biofilm is associated with an increased antibiotic resistance. The principal aim of this study was to evaluate the efficacy of antimicrobial peptides (AMPs in eradication of bacterial biofilms formed on commercially available contact lenses. AMPs were synthesized according to Fmoc/tBu chemistry using the solid-phase method. Minimum inhibitory concentration (MIC and minimum biofilm eradication concentration (MBEC of the compounds were determined. Anti-biofilm activity of the antimicrobial peptides determined at different temperatures (25 °C and 37 °C were compared with the effectiveness of commercially available contact lens solutions. All of the tested compounds exhibited stronger anti-biofilm properties as compared to those of the tested lens solutions. The strongest activity of AMPs was noticed against Gram-positive strains at a temperature of 25 °C. Conclusions: The results of our experiments encourage us toward further studies on AMPs and their potential application in the prophylaxis of contact lens-related eye infections.

  8. New perspectives for natural antimicrobial peptides: application as antinflammatory drugs in a murine model

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    Capparelli Rosanna

    2012-11-01

    Full Text Available Abstract Background Antimicrobial peptides (AMPs are an ancient group of defense molecules. AMPs are widely distributed in nature (being present in mammals, birds, amphibians, insects, plants, and microorganisms. They display bactericidal as well as immunomodulatory properties. The aim of this study was to investigate the antimicrobial and anti-inflammatory activities of a combination of two AMPs (temporin B and the royal jellein I against Staphylococcus epidermidis. Results The temporin B (TB-KK and the royal jelleins I, II, III chemically modified at the C terminal (RJI-C, RJII-C, RJIII-C, were tested for their activity against 10 different Staphylococcus epidermidis strains, alone and in combination. Of the three royal jelleins, RJI-C showed the highest activity. Moreover, the combination of RJI-C and TB-KK (MIX displayed synergistic activity. In vitro, the MIX displayed low hemolytic activity, no NO2- production and the ability to curb the synthesis of the pro-inflammatory cytokines TNF-α and IFN-γ to the same extent as acetylsalicylic acid. In vivo, the MIX sterilized mice infected with Staphylococcus epidermidis in eleven days and inhibited the expression of genes encoding the prostaglandin-endoperoxide synthase 2 (COX-2 and CD64, two important parameters of inflammation. Conclusion The study shows that the MIX – a combination of two naturally occurring peptides - displays both antimicrobial and anti-inflammatory activities.

  9. Evaluation of antibacterial activity of peptide fractions derived from Iranian scorpion Hemiscorpius lepturus

    OpenAIRE

    Kamran Pooshang Bagheri; shabnam radbakhsh; Delavar Shahbazzadeh; Amir Mahmoodzadeh

    2013-01-01

    Background and aim: Continuous appearance of antibiotic resistance bacteria can cause significant complications and mortality. In this regard, tracing for new antimicrobial agents is of great significance. During the past decades, many studies have documented isolation of Antimicrobial Peptides (AMPs) from different sources. These peptides which are responsible for hinnate immunity were purified from human, vertebrates, invertebrates, insects, venomous animals, and plants. This study aimed to...

  10. ANTIMICROBIAL ACTIVITY OF EUGENOL DERIVATIVES Antimikrobielle Aktivität EUGENOL DERIVATE

    OpenAIRE

    George Eyambe, Luis Canales and Bimal K. Banik

    2011-01-01

    The antibacterial properties of the clove plant are due to the presence of eugenol, an aromatic phenolic compound. Eugenol was isolated from clove by stem distillation. The alkene group in eugenol was epoxidized resulting in the synthesis of epoxide-eugenol. The heterocyclic ring in epoxide was cleaved to a bromoalcohol derivative. The compounds synthesized epoxideeugenol, bromo alcohol and euginol were tested for antimicrobial activity against Staphylococcus aureus (ATCC 25923). Epoxide-euge...

  11. Skin-Derived C-Terminal Filaggrin-2 Fragments Are Pseudomonas aeruginosa-Directed Antimicrobials Targeting Bacterial Replication.

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    Britta Hansmann

    2015-09-01

    Full Text Available Soil- and waterborne bacteria such as Pseudomonas aeruginosa are constantly challenging body surfaces. Since infections of healthy skin are unexpectedly rare, we hypothesized that the outermost epidermis, the stratum corneum, and sweat glands directly control the growth of P. aeruginosa by surface-provided antimicrobials. Due to its high abundance in the upper epidermis and eccrine sweat glands, filaggrin-2 (FLG2, a water-insoluble 248 kDa S100 fused-type protein, might possess these innate effector functions. Indeed, recombinant FLG2 C-terminal protein fragments display potent antimicrobial activity against P. aeruginosa and other Pseudomonads. Moreover, upon cultivation on stratum corneum, P. aeruginosa release FLG2 C-terminus-containing FLG2 fragments from insoluble material, indicating liberation of antimicrobially active FLG2 fragments by the bacteria themselves. Analyses of the underlying antimicrobial mechanism reveal that FLG2 C-terminal fragments do not induce pore formation, as known for many other antimicrobial peptides, but membrane blebbing, suggesting an alternative mode of action. The association of the FLG2 fragment with the inner membrane of treated bacteria and its DNA-binding implicated an interference with the bacterial replication that was confirmed by in vitro and in vivo replication assays. Probably through in situ-activation by soil- and waterborne bacteria such as Pseudomonads, FLG2 interferes with the bacterial replication, terminates their growth on skin surface and thus may contributes to the skin's antimicrobial defense shield. The apparent absence of FLG2 at certain body surfaces, as in the lung or of burned skin, would explain their higher susceptibility towards Pseudomonas infections and make FLG2 C-terminal fragments and their derivatives candidates for new Pseudomonas-targeting antimicrobials.

  12. Photoperiod Regulates vgf-Derived Peptide Processing in Siberian Hamsters.

    Science.gov (United States)

    Noli, Barbara; Brancia, Carla; Pilleri, Roberta; D'Amato, Filomena; Messana, Irene; Manconi, Barbara; Ebling, Francis J P; Ferri, Gian-Luca; Cocco, Cristina

    2015-01-01

    VGF mRNA is induced in specific hypothalamic areas of the Siberian hamster upon exposure to short photoperiods, which is associated with a seasonal decrease in appetite and weight loss. Processing of VGF generates multiple bioactive peptides, so the objective of this study was to determine the profile of the VGF-derived peptides in the brain, pituitary and plasma from Siberian hamsters, and to establish whether differential processing might occur in the short day lean state versus long day fat. Antisera against short sequences at the C- or N- termini of proVGF, as well as against NERP-1, TPGH and TLQP peptides, were used for analyses of tissues, and both immunohistochemistry and enzyme linked immunosorbent assay (ELISA) coupled with high-performance liquid (HPLC) or gel chromatography were carried out. VGF peptide immunoreactivity was found within cortex cholinergic perikarya, in multiple hypothalamic nuclei, including those containing vasopressin, and in pituitary gonadotrophs. ELISA revealed that exposure to short day photoperiod led to a down-regulation of VGF immunoreactivity in the cortex, and a less pronounced decrease in the hypothalamus and pituitary, while the plasma VGF levels were not affected by the photoperiod. HPLC and gel chromatography both confirmed the presence of multiple VGF-derived peptides in these tissues, while gel chromatography showed the presence of the VGF precursor in all tissues tested except for the cortex. These observations are consistent with the view that VGF-derived peptides have pleiotropic actions related to changing photoperiod, possibly by regulating cholinergic systems in the cortex, vasopressin hypothalamic pathways, and the reproductive axis.

  13. Photoperiod Regulates vgf-Derived Peptide Processing in Siberian Hamsters.

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    Barbara Noli

    Full Text Available VGF mRNA is induced in specific hypothalamic areas of the Siberian hamster upon exposure to short photoperiods, which is associated with a seasonal decrease in appetite and weight loss. Processing of VGF generates multiple bioactive peptides, so the objective of this study was to determine the profile of the VGF-derived peptides in the brain, pituitary and plasma from Siberian hamsters, and to establish whether differential processing might occur in the short day lean state versus long day fat. Antisera against short sequences at the C- or N- termini of proVGF, as well as against NERP-1, TPGH and TLQP peptides, were used for analyses of tissues, and both immunohistochemistry and enzyme linked immunosorbent assay (ELISA coupled with high-performance liquid (HPLC or gel chromatography were carried out. VGF peptide immunoreactivity was found within cortex cholinergic perikarya, in multiple hypothalamic nuclei, including those containing vasopressin, and in pituitary gonadotrophs. ELISA revealed that exposure to short day photoperiod led to a down-regulation of VGF immunoreactivity in the cortex, and a less pronounced decrease in the hypothalamus and pituitary, while the plasma VGF levels were not affected by the photoperiod. HPLC and gel chromatography both confirmed the presence of multiple VGF-derived peptides in these tissues, while gel chromatography showed the presence of the VGF precursor in all tissues tested except for the cortex. These observations are consistent with the view that VGF-derived peptides have pleiotropic actions related to changing photoperiod, possibly by regulating cholinergic systems in the cortex, vasopressin hypothalamic pathways, and the reproductive axis.

  14. Multiple Functions of the New Cytokine-Based Antimicrobial Peptide Thymic Stromal Lymphopoietin (TSLP).

    Science.gov (United States)

    Bjerkan, Louise; Sonesson, Andreas; Schenck, Karl

    2016-01-01

    Thymic stromal lymphopoietin (TSLP) is a pleiotropic cytokine, hitherto mostly known to be involved in inflammatory responses and immunoregulation. The human tslp gene gives rise to two transcription and translation variants: a long form (lfTSLP) that is induced by inflammation, and a short, constitutively-expressed form (sfTSLP), that appears to be downregulated by inflammation. The TSLP forms can be produced by a number of cell types, including epithelial and dendritic cells (DCs). lfTSLP can activate mast cells, DCs, and T cells through binding to the lfTSLP receptor (TSLPR) and has a pro-inflammatory function. In contrast, sfTSLP inhibits cytokine secretion of DCs, but the receptor mediating this effect is unknown. Our recent studies have demonstrated that both forms of TSLP display potent antimicrobial activity, exceeding that of many other known antimicrobial peptides (AMPs), with sfTSLP having the strongest effect. The AMP activity is primarily mediated by the C-terminal region of the protein and is localized within a 34-mer peptide (MKK34) that spans the C-terminal α-helical region in TSLP. Fluorescent studies of peptide-treated bacteria, electron microscopy, and liposome leakage models showed that MKK34 exerted membrane-disrupting effects comparable to those of LL-37. Expression of TSLP in skin, oral mucosa, salivary glands, and intestine is part of the defense barrier that aids in the control of both commensal and pathogenic microbes. PMID:27399723

  15. Activity of antimicrobial peptide mimetics in the oral cavity: I. Activity against biofilms of Candida albicans.

    Science.gov (United States)

    Hua, J; Yamarthy, R; Felsenstein, S; Scott, R W; Markowitz, K; Diamond, G

    2010-12-01

    Naturally occurring antimicrobial peptides hold promise as therapeutic agents against oral pathogens such as Candida albicans but numerous difficulties have slowed their development. Synthetic, non-peptidic analogs that mimic the properties of these peptides have many advantages and exhibit potent, selective antimicrobial activity. Several series of mimetics (with molecular weight oral Candida strains as a proof-of-principle for their antifungal properties. One phenylalkyne and several arylamide compounds with reduced mammalian cytotoxicities were found to be active against C. albicans. These compounds demonstrated rapid fungicidal activity in liquid culture even in the presence of saliva, and demonstrated synergy with standard antifungal agents. When assayed against biofilms grown on denture acrylic, the compounds exhibited potent fungicidal activity as measured by metabolic and fluorescent viability assays. Repeated passages in sub-minimum inhibitory concentration levels did not lead to resistant Candida, in contrast to fluconazole. Our results demonstrate the proof-of principle for the use of these compounds as anti-Candida agents, and their further testing is warranted as novel anti-Candida therapies.

  16. Rhizosecretion of The Recombinant Antimicrobial Peptide Ranalexin from Transgenic Tobacco Hairy Roots

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    Rasha Abou Aleinein

    2015-07-01

    Full Text Available Rhizosecretion of functional recombinant proteins from in vitro cultured roots into the hydroponic medium offers an attractive technology to simplify down-stream purification procedures. Aim of the present study was the production and secretion of the antimicrobial peptide (AMP ranalexin from Nicotiana tabacum hairy roots which were transformed by agroinfection. A His-tagged ranalexin was expressed under the control of CaMV 35S promoter and directed into the plant secretion pathway by fusing its N terminus to the ER signal peptide of calreticulin. The maximal accumulation of ranalexin in hairy root tissue after 20-25 days of culture accounted for about 3.36% of the total soluble protein. Secreted ranalexin reached a concentration of 0.28 mg/L in the medium on day 25. Extracellular ranalexin level could be increased to 1.64 mg/L by the addition of polyvinylpyrrolidone to the culture medium. The secreted ranalexin is active against Gram positive and Gram negative bacteria including strains which are multiresistant against antibiotics, such as methicillin-resistant Staphylococcus aureus MRSA, vancomycin-resistant Enterococcus VRE, Streptococcus pyogenes, Escherichia coli, Acinetobacter baumanii as well as clinical MRSA isolates. Our results demonstrate the usefulness of plant tissue cultures especially tobacco hairy roots as an alternative production system of ranalexin and other antimicrobial peptides.

  17. Prediction of antimicrobial peptides based on the adaptive neuro-fuzzy inference system application.

    Science.gov (United States)

    Fernandes, Fabiano C; Rigden, Daniel J; Franco, Octavio L

    2012-01-01

    Antimicrobial peptides (AMPs) are widely distributed defense molecules and represent a promising alternative for solving the problem of antibiotic resistance. Nevertheless, the experimental time required to screen putative AMPs makes computational simulations based on peptide sequence analysis and/or molecular modeling extremely attractive. Artificial intelligence methods acting as simulation and prediction tools are of great importance in helping to efficiently discover and design novel AMPs. In the present study, state-of-the-art published outcomes using different prediction methods and databases were compared to an adaptive neuro-fuzzy inference system (ANFIS) model. Data from our study showed that ANFIS obtained an accuracy of 96.7% and a Matthew's Correlation Coefficient (MCC) of0.936, which proved it to be an efficient model for pattern recognition in antimicrobial peptide prediction. Furthermore, a lower number of input parameters were needed for the ANFIS model, improving the speed and ease of prediction. In summary, due to the fuzzy nature ofAMP physicochemical properties, the ANFIS approach presented here can provide an efficient solution for screening putative AMP sequences and for exploration of properties characteristic of AMPs. PMID:23193592

  18. Multiple Functions of the New Cytokine-Based Antimicrobial Peptide Thymic Stromal Lymphopoietin (TSLP

    Directory of Open Access Journals (Sweden)

    Louise Bjerkan

    2016-07-01

    Full Text Available Thymic stromal lymphopoietin (TSLP is a pleiotropic cytokine, hitherto mostly known to be involved in inflammatory responses and immunoregulation. The human tslp gene gives rise to two transcription and translation variants: a long form (lfTSLP that is induced by inflammation, and a short, constitutively-expressed form (sfTSLP, that appears to be downregulated by inflammation. The TSLP forms can be produced by a number of cell types, including epithelial and dendritic cells (DCs. lfTSLP can activate mast cells, DCs, and T cells through binding to the lfTSLP receptor (TSLPR and has a pro-inflammatory function. In contrast, sfTSLP inhibits cytokine secretion of DCs, but the receptor mediating this effect is unknown. Our recent studies have demonstrated that both forms of TSLP display potent antimicrobial activity, exceeding that of many other known antimicrobial peptides (AMPs, with sfTSLP having the strongest effect. The AMP activity is primarily mediated by the C-terminal region of the protein and is localized within a 34-mer peptide (MKK34 that spans the C-terminal α-helical region in TSLP. Fluorescent studies of peptide-treated bacteria, electron microscopy, and liposome leakage models showed that MKK34 exerted membrane-disrupting effects comparable to those of LL-37. Expression of TSLP in skin, oral mucosa, salivary glands, and intestine is part of the defense barrier that aids in the control of both commensal and pathogenic microbes.

  19. Defensive remodeling: How bacterial surface properties and biofilm formation promote resistance to antimicrobial peptides.

    Science.gov (United States)

    Nuri, Reut; Shprung, Tal; Shai, Yechiel

    2015-11-01

    Multidrug resistance bacteria are a major concern worldwide. These pathogens cannot be treated with conventional antibiotics and thus alternative therapeutic agents are needed. Antimicrobial peptides (AMPs) are considered to be good candidates for this purpose. Most AMPs are short and positively charged amphipathic peptides, which are found in all known forms of life. AMPs are known to kill bacteria by binding to the negatively charged bacterial surface, and in most cases cause membrane disruption. Resistance toward AMPs can be developed, by modification of bacterial surface molecules, secretion of protective material and up-regulation or elimination of specific proteins. Because of the general mechanisms of attachment and action of AMPs, bacterial resistance to AMPs often involves biophysical and biochemical changes such as surface rigidity, cell wall thickness, surface charge, as well as membrane and cell wall modification. Here we focus on the biophysical, surface and surrounding changes that bacteria undergo in acquiring resistance to AMPs. In addition we discuss the question of whether bacterial resistance to administered AMPs might compromise our innate immunity to endogenous AMPs. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.

  20. Anti-biofilm activity of ultrashort cinnamic acid peptide derivatives against medical device-related pathogens.

    Science.gov (United States)

    Laverty, Garry; McCloskey, Alice P; Gorman, Sean P; Gilmore, Brendan F

    2015-10-01

    The threat of antimicrobial resistance has placed increasing emphasis on the development of innovative approaches to eradicate multidrug-resistant pathogens. Biofilm-forming microorganisms, for example, Staphylococcus epidermidis and Staphylococcus aureus, are responsible for increased incidence of biomaterial infection, extended hospital stays and patient morbidity and mortality. This paper highlights the potential of ultrashort tetra-peptide conjugated to hydrophobic cinnamic acid derivatives. These peptidomimetic molecules demonstrate selective and highly potent activity against resistant biofilm forms of Gram-positive medical device-related pathogens. 3-(4-Hydroxyphenyl)propionic)-Orn-Orn-Trp-Trp-NH2 displays particular promise with minimum biofilm eradication concentration (MBEC) values of 125 µg/ml against methicillin sensitive (ATCC 29213) and resistant (ATCC 43300) S. aureus and activity shown against biofilm forms of Escherichia coli (MBEC: 1000 µg/ml). Kill kinetics confirms complete eradication of established 24-h biofilms at MBEC with 6-h exposure. Reduced cell cytotoxicity, relative to Gram-positive pathogens, was proven via tissue culture (HaCaT) and haemolysis assays (equine erythrocytes). Existing in nature as part of the immune response, antimicrobial peptides display great promise for exploitation by the pharmaceutical industry in order to increase the library of available therapeutic molecules. Ultrashort variants are particularly promising for translation as clinical therapeutics as they are more cost-effective, easier to synthesise and can be tailored to specific functional requirements based on the primary sequence allowing factors such as spectrum of activity to be varied. PMID:26310860

  1. Food Derived Bioactive Peptides and Intestinal Barrier Function

    Directory of Open Access Journals (Sweden)

    Olga Martínez-Augustin

    2014-12-01

    Full Text Available A wide range of food-derived bioactive peptides have been shown to exert health-promoting actions and are therefore considered functional foods or nutraceuticals. Some of these actions are related to the maintenance, reinforcement or repairment of the intestinal barrier function (IBF whose role is to selectively allow the absorption of water, nutrients and ions while preventing the influx of microorganisms from the intestinal lumen. Alterations in the IBF have been related to many disorders, such as inflammatory bowel disease or metabolic syndrome. Components of IBF are the intestinal epithelium, the mucus layer, secretory immunoglobulin A and cells of the innate and adaptive immune systems. Here we review the effects of food derived bioactive peptides on these IBF components. In vitro and in vivo effects, both in healthy and disease states, have been reviewed. Although limited, the available information indicates a potential for food-derived peptides to modify IBF and to contribute to disease treatment, but further research is needed to better isolate responsible peptides, and to help define their mode of action.

  2. Antimicrobial peptides on calcium phosphate-coated titanium for the prevention of implant-associated infections

    DEFF Research Database (Denmark)

    Kazemzadeh-Narbat, Mehdi; Kindrachuk, Jason; Duan, Ke;

    2010-01-01

    ) bacteria with 106-fold reductions of both bacterial strains within 30 min as assessed by measuring colony-forming units (CFU). Repeated CFU assays on the same CaP-Tet213 specimen demonstrated retention of antimicrobial activity by the CaP-Tet213 surfaces through four test cycles. The susceptibility of......Prevention of implant-associated infections has been one of the main challenges in orthopaedic surgery. This challenge is further complicated by the concern over the development of antibiotic resistance as a result of using traditional antibiotics for infection prophylaxis. The objective of this...... study was to develop a technique that enables the loading and local delivery of a unique group of cationic antimicrobial peptides (AMP) through implant surfaces. A thin layer of micro-porous calcium phosphate (CaP) coating was processed by electrolytic deposition onto the surface of titanium as the drug...

  3. Characterization and activity of an immobilized antimicrobial peptide containing bactericidal PEG-hydrogel.

    Science.gov (United States)

    Cleophas, Rik T C; Sjollema, Jelmer; Busscher, Henk J; Kruijtzer, John A W; Liskamp, Rob M J

    2014-09-01

    A single step immobilization-polymerization strategy of a highly active antimicrobial peptide into a soft hydrogel network on a poly(ethylene terephthalate) surface using thiol-ene chemistry is described. The bactericidal hydrogel was molecularly characterized via Coomassie and Lowry assay protein staining agents as well as by X-ray photoelectron spectroscopy. The bactericidal activity was established against Staphylococcus aureus and Staphylococcus epidermidis, two bacterial strains commonly associated with biomaterial infections. To gain further insight into the biological stability, the hydrogels were incubated with human serum prior to activity testing without loss of activity. These studies revealed a promising bactericidal hydrogel with good stability under physiological conditions.

  4. A novel PCR-based method for high throughput prokaryotic expression of antimicrobial peptide genes

    Directory of Open Access Journals (Sweden)

    Ke Tao

    2012-03-01

    Full Text Available Abstract Background To facilitate the screening of large quantities of new antimicrobial peptides (AMPs, we describe a cost-effective method for high throughput prokaryotic expression of AMPs. EDDIE, an autoproteolytic mutant of the N-terminal autoprotease, Npro, from classical swine fever virus, was selected as a fusion protein partner. The expression system was used for high-level expression of six antimicrobial peptides with different sizes: Bombinin-like peptide 7, Temporin G, hexapeptide, Combi-1, human Histatin 9, and human Histatin 6. These expressed AMPs were purified and evaluated for antimicrobial activity. Results Two or four primers were used to synthesize each AMP gene in a single step PCR. Each synthetic gene was then cloned into the pET30a/His-EDDIE-GFP vector via an in vivo recombination strategy. Each AMP was then expressed as an Npro fusion protein in Escherichia coli. The expressed fusion proteins existed as inclusion bodies in the cytoplasm and the expression levels of the six AMPs reached up to 40% of the total cell protein content. On in vitro refolding, the fusion AMPs was released from the C-terminal end of the autoprotease by self-cleavage, leaving AMPs with an authentic N terminus. The released fusion partner was easily purified by Ni-NTA chromatography. All recombinant AMPs displayed expected antimicrobial activity against E. coli, Micrococcus luteus and S. cerevisia. Conclusions The method described in this report allows the fast synthesis of genes that are optimized for over-expression in E. coli and for the production of sufficiently large amounts of peptides for functional and structural characterization. The Npro partner system, without the need for chemical or enzymatic removal of the fusion tag, is a low-cost, efficient way of producing AMPs for characterization. The cloning method, combined with bioinformatic analyses from genome and EST sequence data, will also be useful for screening new AMPs. Plasmid pET30a

  5. Cathelicidins: peptides with antimicrobial, immunomodulatory, anti-inflammatory, angiogenic, anticancer and procancer activities.

    Science.gov (United States)

    Wong, Jack Ho; Ye, Xiu Juan; Ng, Tzi Bun

    2013-09-01

    The family of peptides designated as cathelicidins was identified over a decade ago. Cathelicidins have since gained increasing recognition, both as endogenous antibiotics and as effector molecules of the innate immune system. The human cathelicidin LL-37 is widely expressed in human tissues and plays diverse biological roles. It contributes substantially to host defense and impacts multiple aspects of immunity. In view of the escalating importance of cathelicidins, the activities of LL-37 with an emphasis on antimicrobial, immunomodulatory, anti-inflammatory, angiogenic, anticancer and procancer effects are discussed in this review article.

  6. Molecular dynamics investigation of the influence of anionic and zwitterionic interfaces on antimicrobial peptides' structure: implications for peptide toxicity and activity

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Kaznessis, Yiannis N

    2006-01-01

    Molecular dynamics simulations of three related helical antimicrobial peptides have been carried out in zwitterionic diphosphocholine (DPC) micelles and anionic sodiumdodecylsulfate (SDS) micelles. These systems can be considered as model mammalian and bacterial membrane interfaces, respectively...... properties. Based on the simulations, we argue that secondary structure stability often leads to toxic properties. We also propose that G10 and T7 operate by the carpet mechanism of cell lysis. Toxicity of peptides operating by the carpet mechanism can be attenuated by reducing the peptide helical content...... amphipathic peptide structures, which bind weakly to the micelle. Simulations in SDS were carried out to compare the influence of membrane electrostatics on peptide structure. All three peptides bound strongly to SDS, and retained helical form. This corresponds well with their equally potent antibacterial...

  7. Identification of multiple peptides with antioxidant and antimicrobial activities from skin and its secretions of Hylarana taipehensis, Amolops lifanensis, and Amolops granulosus.

    Science.gov (United States)

    Guo, Chao; Hu, Yuhong; Li, Jing; Liu, Yuliang; Li, Sihan; Yan, Keqiang; Wang, Xiao; Liu, Jingze; Wang, Hui

    2014-10-01

    Amphibian skin and its secretions contain many kinds of peptides with different bioactivities. In this study, a large number of peptides including antioxidant and antimicrobial peptides were identified from three East Asian frog species Hylarana taipehensis, Amolops lifanensis, and Amolops granulosus. The majority of these peptides were antimicrobial peptides, while eight antioxidant peptides were identified, which included two novel peptides taipehensin-1TP1 (TLIWEFYHQILDEYNKENKG) and taipehensin-2TP1 (CLMARPNYRCKIFKQC). These antioxidant peptides exhibited the ability to scavenge ABTS and/or DPPH free radicals. Moreover, six out of eight antioxidant peptides temporin-TP1, brevinin-1TP1, brevinin-1TP2, brevinin-1TP3, brevinin-1LF1, and palustrin-2GN1 also showed antimicrobial activity.

  8. Impact of the antimicrobial peptide Novicidin on membrane structure and integrity

    DEFF Research Database (Denmark)

    Nielsen, Søren B; Otzen, Daniel Erik

    2010-01-01

    We have studied the impact of an 18-residue cationic antimicrobial peptide Novicidin (Nc) on the structure and integrity of partially anionic lipid membranes using oriented circular dichroism (OCD), quartz crystal microbalance with dissipation (QCM-D), dual polarization interferometry (DPI...... fluorescence spectroscopy and by loss of lipid alignment in DPI analysis. Laurdan generalized polarity shows a decrease in water accessibility or mobility in the hydrophobic/hydrophilic interface of the lipid membrane, consistent with rearrangement of lipid packing. QCM-D studies on the interaction of Nc...... with lipid membranes emphasize the importance of including the dissipation factor in data analysis, revealing formation of a highly hydrated film after exposure to 3muMNc. Our findings suggest a carpet mechanism of membrane disruption in which peptide binding first induces leakage at a critical surface...

  9. Antimicrobial peptides and nitric oxide production by neutrophils from periodontitis subjects.

    Science.gov (United States)

    Mariano, F S; Campanelli, A P; Nociti Jr, F H; Mattos-Graner, R O; Gonçalves, R B

    2012-11-01

    Neutrophils play an important role in periodontitis by producing nitric oxide (NO) and antimicrobial peptides, molecules with microbicidal activity via oxygen-dependent and -independent mechanisms, respectively. It is unknown whether variation in the production of antimicrobial peptides such as LL-37, human neutrophil peptides (HNP) 1-3, and NO by neutrophils influences the pathogenesis of periodontal diseases. We compared the production of these peptides and NO by lipopolysaccharide (LPS)-stimulated neutrophils isolated from healthy subjects and from patients with periodontitis. Peripheral blood neutrophils were cultured with or without Aggregatibacter actinomycetemcomitans-LPS (Aa-LPS), Porphyromonas gingivalis-LPS (Pg-LPS) and Escherichia coli-LPS (Ec-LPS). qRT-PCR was used to determine quantities of HNP 1-3 and LL-37 mRNA in neutrophils. Amounts of HNP 1-3 and LL-37 proteins in the cell culture supernatants were also determined by ELISA. In addition, NO levels in neutrophil culture supernatants were quantitated by the Griess reaction. Neutrophils from periodontitis patients cultured with Aa-LPS, Pg-LPS and Ec-LPS expressed higher HNP 1-3 mRNA than neutrophils from healthy subjects. LL-37 mRNA expression was higher in neutrophils from patients stimulated with Aa-LPS. Neutrophils from periodontitis patients produced significantly higher LL-37 protein levels than neutrophils from healthy subjects when stimulated with Pg-LPS and Ec-LPS, but no difference was observed in HNP 1-3 production. Neutrophils from periodontitis patients cultured or not with Pg-LPS and Ec-LPS produced significantly lower NO levels than neutrophils from healthy subjects. The significant differences in the production of LL-37 and NO between neutrophils from healthy and periodontitis subjects indicate that production of these molecules might influence individual susceptibility to important periodontal pathogens.

  10. Antimicrobial peptides and nitric oxide production by neutrophils from periodontitis subjects

    Directory of Open Access Journals (Sweden)

    F.S. Mariano

    2012-11-01

    Full Text Available Neutrophils play an important role in periodontitis by producing nitric oxide (NO and antimicrobial peptides, molecules with microbicidal activity via oxygen-dependent and -independent mechanisms, respectively. It is unknown whether variation in the production of antimicrobial peptides such as LL-37, human neutrophil peptides (HNP 1-3, and NO by neutrophils influences the pathogenesis of periodontal diseases. We compared the production of these peptides and NO by lipopolysaccharide (LPS-stimulated neutrophils isolated from healthy subjects and from patients with periodontitis. Peripheral blood neutrophils were cultured with or without Aggregatibacter actinomycetemcomitans-LPS (Aa-LPS, Porphyromonas gingivalis-LPS (Pg-LPS and Escherichia coli-LPS (Ec-LPS. qRT-PCR was used to determine quantities of HNP 1-3 and LL-37 mRNA in neutrophils. Amounts of HNP 1-3 and LL-37 proteins in the cell culture supernatants were also determined by ELISA. In addition, NO levels in neutrophil culture supernatants were quantitated by the Griess reaction. Neutrophils from periodontitis patients cultured with Aa-LPS, Pg-LPS and Ec-LPS expressed higher HNP 1-3 mRNA than neutrophils from healthy subjects. LL-37 mRNA expression was higher in neutrophils from patients stimulated with Aa-LPS. Neutrophils from periodontitis patients produced significantly higher LL-37 protein levels than neutrophils from healthy subjects when stimulated with Pg-LPS and Ec-LPS, but no difference was observed in HNP 1-3 production. Neutrophils from periodontitis patients cultured or not with Pg-LPS and Ec-LPS produced significantly lower NO levels than neutrophils from healthy subjects. The significant differences in the production of LL-37 and NO between neutrophils from healthy and periodontitis subjects indicate that production of these molecules might influence individual susceptibility to important periodontal pathogens.

  11. Enhanced membrane pore formation through high-affinity targeted antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Christopher J Arnusch

    Full Text Available Many cationic antimicrobial peptides (AMPs target the unique lipid composition of the prokaryotic cell membrane. However, the micromolar activities common for these peptides are considered weak in comparison to nisin, which follows a targeted, pore-forming mode of action. Here we show that AMPs can be modified with a high-affinity targeting module, which enables membrane permeabilization at low concentration. Magainin 2 and a truncated peptide analog were conjugated to vancomycin using click chemistry, and could be directed towards specific membrane embedded receptors both in model membrane systems and whole cells. Compared with untargeted vesicles, a gain in permeabilization efficacy of two orders of magnitude was reached with large unilamellar vesicles that included lipid II, the target of vancomycin. The truncated vancomycin-peptide conjugate showed an increased activity against vancomycin resistant Enterococci, whereas the full-length conjugate was more active against a targeted eukaryotic cell model: lipid II containing erythrocytes. This study highlights that AMPs can be made more selective and more potent against biological membranes that contain structures that can be targeted.

  12. Human antimicrobial peptide histatin 5 is a cell-penetrating peptide targeting mitochondrial ATP synthesis in Leishmania.

    Science.gov (United States)

    Luque-Ortega, Juan Román; van't Hof, Wim; Veerman, Enno C I; Saugar, José M; Rivas, Luis

    2008-06-01

    Histatin 5 (Hst5) is a human salivary antimicrobial peptide that targets fungal mitochondria. In the human parasitic protozoa Leishmania, the mitochondrial ATP production is essential, as it lacks the bioenergetic switch between glycolysis and oxidative phosphorylation described in some yeasts. On these premises, Hst5 activity was assayed on both stages of its life cycle, promastigotes and amastigotes (LC(50)=7.3 and 14.4 microM, respectively). In a further step, its lethal mechanism was studied. The main conclusions drawn were as follows: 1) Hst5 causes limited and temporary damage to the plasma membrane of the parasites, as assessed by electron microscopy, depolarization, and entrance of the vital dye SYTOX Green; 2) Hst5 translocates into the cytoplasm of Leishmania in an achiral receptor-independent manner with accumulation into the mitochondrion, as shown by confocal microscopy; and 3) Hst5 produces a bioenergetic collapse of the parasite, caused essentially by the decrease of mitochondrial ATP synthesis through inhibition of F(1)F(0)-ATPase, with subsequent fast ATP exhaustion. By using the Hst5 enantiomer, it was found that the key steps of its lethal mechanism involved no chiral recognition. Hst5 thus constitutes the first leishmanicidal peptide with a defined nonstereospecific intracellular target. The prospects of its development, by its own or as a carrier molecule for other leishmanicidal molecules, into a novel anti-Leishmania drug with a preferential subcellular accumulation are discussed. PMID:18230684

  13. The MisR Response Regulator Is Necessary for Intrinsic Cationic Antimicrobial Peptide and Aminoglycoside Resistance in Neisseria gonorrhoeae.

    Science.gov (United States)

    Kandler, Justin L; Holley, Concerta L; Reimche, Jennifer L; Dhulipala, Vijaya; Balthazar, Jacqueline T; Muszyński, Artur; Carlson, Russell W; Shafer, William M

    2016-08-01

    During infection, the sexually transmitted pathogen Neisseria gonorrhoeae (the gonococcus) encounters numerous host-derived antimicrobials, including cationic antimicrobial peptides (CAMPs) produced by epithelial and phagocytic cells. CAMPs have both direct and indirect killing mechanisms and help link the innate and adaptive immune responses during infection. Gonococcal CAMP resistance is likely important for avoidance of host nonoxidative killing systems expressed by polymorphonuclear granulocytes (e.g., neutrophils) and intracellular survival. Previously studied gonococcal CAMP resistance mechanisms include modification of lipid A with phosphoethanolamine by LptA and export of CAMPs by the MtrCDE efflux pump. In the related pathogen Neisseria meningitidis, a two-component regulatory system (2CRS) termed MisR-MisS has been shown to contribute to the capacity of the meningococcus to resist CAMP killing. We report that the gonococcal MisR response regulator but not the MisS sensor kinase is involved in constitutive and inducible CAMP resistance and is also required for intrinsic low-level resistance to aminoglycosides. The 4- to 8-fold increased susceptibility of misR-deficient gonococci to CAMPs and aminoglycosides was independent of phosphoethanolamine decoration of lipid A and the levels of the MtrCDE efflux pump and seemed to correlate with a general increase in membrane permeability. Transcriptional profiling and biochemical studies confirmed that expression of lptA and mtrCDE was not impacted by the loss of MisR. However, several genes encoding proteins involved in membrane integrity and redox control gave evidence of being MisR regulated. We propose that MisR modulates the levels of gonococcal susceptibility to antimicrobials by influencing the expression of genes involved in determining membrane integrity. PMID:27216061

  14. Antiinflammatory properties of a peptide derived from interleukin-4

    DEFF Research Database (Denmark)

    Klementiev, Boris; Enevoldsen, Maj N; Li, Shizhong;

    2013-01-01

    Interleukin-4 (IL-4) is a potent antiinflammatory cytokine. However its use in the clinic is hampered by side effects. We here describe the identification of a novel synthetic peptide, termed Ph8, derived from α-helix C of IL-4, which interacts with IL-4 receptor α (IL-4Rα). Employing various cul...... and reduced acute inflammation in carrageenan-induced edema. Our findings indicate that Ph8 is a promising potential drug candidate for the treatment of inflammatory diseases....

  15. Antimicrobial Peptides:Design and Application%抗菌肽的设计及其应用

    Institute of Scientific and Technical Information of China (English)

    陈宇婷; 王长海; 严秀文; 黎军胜

    2013-01-01

    抗菌肽(AMP)是生物体内先天免疫系统的一个组成部分,保护机体免受致病微生物的入侵.抗菌肽具有很强的广谱抗菌活性,可抑制革兰氏阳性菌、革兰氏阴性菌、真菌和病毒的生长.为克服微生物对抗生素耐药性的问题,目前阳离子抗菌肽已被考虑作为抗生素的潜在替代品.本文将阐述抗菌肽的作用机理、选择性抗菌肽的设计及其应用.%Antimicrobial peptide(AMP) is an integral part of the innate immune system in living organisms that protect hosts from invading pathogenic microorganism.AMPs have strong antimicrobial activity against a wide-range of species,including gram-positive and gram-negative bacteria,fungi,and viruses.In order to overcome the problem of resistance,cationic antimicrobial peptides are currently being considered as a potential alternative for antibiotics.This review focuses on the mechanism and application of the antimicrobial peptides and discusses the design of molecular targeted antimicrobial peptides.

  16. Structure-activity relationships of the antimicrobial peptide arasin 1 - and mode of action studies of the N-terminal, proline-rich region.

    Directory of Open Access Journals (Sweden)

    Victoria S Paulsen

    Full Text Available Arasin 1 is a 37 amino acid long proline-rich antimicrobial peptide isolated from the spider crab, Hyas araneus. In this work the active region of arasin 1 was identified through structure-activity studies using different peptide fragments derived from the arasin 1 sequence. The pharmacophore was found to be located in the proline/arginine-rich NH(2 terminus of the peptide and the fragment arasin 1(1-23 was almost equally active to the full length peptide. Arasin 1 and its active fragment arasin 1(1-23 were shown to be non-toxic to human red blood cells and arasin 1(1-23 was able to bind chitin, a component of fungal cell walls and the crustacean shell. The mode of action of the fully active N-terminal arasin 1(1-23 was explored through killing kinetic and membrane permeabilization studies. At the minimal inhibitory concentration (MIC, arasin 1(1-23 was not bactericidal and had no membrane disruptive effect. In contrast, at concentrations of 5×MIC and above it was bactericidal and interfered with membrane integrity. We conclude that arasin 1(1-23 has a different mode of action than lytic peptides, like cecropin P1. Thus, we suggest a dual mode of action for arasin 1(1-23 involving membrane disruption at peptide concentrations above MIC, and an alternative mechanism of action, possibly involving intracellular targets, at MIC.

  17. The Role of Phosphoglycans in the Susceptibility of Leishmania mexicana to the Temporin Family of Anti-Microbial Peptides

    Directory of Open Access Journals (Sweden)

    Gabriela A. Eggimann

    2015-02-01

    Full Text Available Natural product antimicrobial peptides (AMPs have been proposed as promising agents against the Leishmania species, insect vector borne protozoan parasites causing the neglected tropical disease leishmaniasis. However, recent studies have shown that the mammalian pathogenic amastigote form of L. mexicana, a causative agent of cutaneous leishmaniasis, is resistant to the amphibian-derived temporin family of AMPs when compared to the insect stage promastigote form. The mode of resistance is unknown, however the insect and mammalian stages of Leishmania possess radically different cell surface coats, with amastigotes displaying low (or zero quantities of lipophosphoglycan (LPG and proteophosphoglycan (PPG, macromolecules which form thick a glycocalyx in promastigotes. It has been predicted that negatively charged LPG and PPG influence the sensitivity/resistance of promastigote forms to cationic temporins. Using LPG and PPG mutant L. mexicana, and an extended range of temporins, in this study we demonstrated that whilst LPG has little role, PPG is a major factor in promastigote sensitivity to the temporin family of AMPs, possibly due to the conferred anionic charge. Therefore, the lack of PPG seen on the surface of pathogenic amastigote L. mexicana may be implicated in their resistance to these peptides.

  18. Genomic Signatures of Experimental Adaptation to Antimicrobial Peptides in Staphylococcus aureus.

    Science.gov (United States)

    Johnston, Paul R; Dobson, Adam J; Rolff, Jens

    2016-01-01

    The evolution of resistance against antimicrobial peptides has long been considered unlikely due to their mechanism of action, yet experimental selection with antimicrobial peptides (AMPs) results in rapid evolution of resistance in several species of bacteria. Although numerous studies have utilized mutant screens to identify loci that determine AMP susceptibility, there is a dearth of data concerning the genomic changes that accompany experimental evolution of AMP resistance. Using genome resequencing, we analyzed the mutations that arose during experimental evolution of resistance to the cationic AMPs iseganan, melittin, and pexiganan, as well as to a combination of melittin and pexiganan, or to the aminoglycoside antibiotic streptomycin. Analysis of 17 independently replicated Staphylococcus aureus selection lines, including unselected controls, showed that each AMP selected for mutations at distinct loci. We identify mutations in genes involved in the synthesis and maintenance of the cell envelope. These include genes previously identified from mutant screens for AMP resistance, and genes involved in the response to AMPs and cell-wall-active antibiotics. Furthermore, transposon insertion mutants were used to verify that a number of the identified genes are directly involved in determining AMP susceptibility. Strains selected for AMP resistance under controlled experimental evolution displayed consistent AMP-specific mutations in genes that determine AMP susceptibility. This suggests that different routes to evolve resistance are favored within a controlled genetic background. PMID:27172179

  19. Genomic Signatures of Experimental Adaptation to Antimicrobial Peptides in Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Paul R. Johnston

    2016-06-01

    Full Text Available The evolution of resistance against antimicrobial peptides has long been considered unlikely due to their mechanism of action, yet experimental selection with antimicrobial peptides (AMPs results in rapid evolution of resistance in several species of bacteria. Although numerous studies have utilized mutant screens to identify loci that determine AMP susceptibility, there is a dearth of data concerning the genomic changes that accompany experimental evolution of AMP resistance. Using genome resequencing, we analyzed the mutations that arose during experimental evolution of resistance to the cationic AMPs iseganan, melittin, and pexiganan, as well as to a combination of melittin and pexiganan, or to the aminoglycoside antibiotic streptomycin. Analysis of 17 independently replicated Staphylococcus aureus selection lines, including unselected controls, showed that each AMP selected for mutations at distinct loci. We identify mutations in genes involved in the synthesis and maintenance of the cell envelope. These include genes previously identified from mutant screens for AMP resistance, and genes involved in the response to AMPs and cell-wall-active antibiotics. Furthermore, transposon insertion mutants were used to verify that a number of the identified genes are directly involved in determining AMP susceptibility. Strains selected for AMP resistance under controlled experimental evolution displayed consistent AMP-specific mutations in genes that determine AMP susceptibility. This suggests that different routes to evolve resistance are favored within a controlled genetic background.

  20. Mode of action and membrane specificity of the antimicrobial peptide snakin-2.

    Science.gov (United States)

    Herbel, Vera; Wink, Michael

    2016-01-01

    Antimicrobial peptides (AMPs) are a diverse group of short, cationic peptides which are naturally occurring molecules in the first-line defense of most living organisms. They represent promising candidates for the treatment of pathogenic microorganisms. Snakin-2 (SN2) from tomato (Solanum lycopersicum) is stabilized through six intramolecular disulphide bridges; it shows broad-spectrum antimicrobial activity against bacteria and fungi, and it agglomerates single cells prior to killing. In this study, we further characterized SN2 by providing time-kill curves and corresponding growth inhibition analysis of model organisms, such as E. coli or B. subtilis. SN2 was produced recombinantly in E. coli with thioredoxin as fusion protein, which was removed after affinity purification by proteolytic digestion. Furthermore, the target specificity of SN2 was investigated by means of hemolysis and hemagglutination assays; its effect on plant cell membranes of isolated protoplasts was investigated by microscopy. SN2 shows a non-specific pore-forming effect in all tested membranes. We suggest that SN2 could be useful as a preservative agent to protect food, pharmaceuticals, or cosmetics from decomposition by microbes. PMID:27190708

  1. Insect antimicrobial peptides show potentiating functional interactions against Gram-negative bacteria

    Science.gov (United States)

    Rahnamaeian, Mohammad; Cytryńska, Małgorzata; Zdybicka-Barabas, Agnieszka; Dobslaff, Kristin; Wiesner, Jochen; Twyman, Richard M.; Zuchner, Thole; Sadd, Ben M.; Regoes, Roland R.; Schmid-Hempel, Paul; Vilcinskas, Andreas

    2015-01-01

    Antimicrobial peptides (AMPs) and proteins are important components of innate immunity against pathogens in insects. The production of AMPs is costly owing to resource-based trade-offs, and strategies maximizing the efficacy of AMPs at low concentrations are therefore likely to be advantageous. Here, we show the potentiating functional interaction of co-occurring insect AMPs (the bumblebee linear peptides hymenoptaecin and abaecin) resulting in more potent antimicrobial effects at low concentrations. Abaecin displayed no detectable activity against Escherichia coli when tested alone at concentrations of up to 200 μM, whereas hymenoptaecin affected bacterial cell growth and viability but only at concentrations greater than 2 μM. In combination, as little as 1.25 μM abaecin enhanced the bactericidal effects of hymenoptaecin. To understand these potentiating functional interactions, we investigated their mechanisms of action using atomic force microscopy and fluorescence resonance energy transfer-based quenching assays. Abaecin was found to reduce the minimal inhibitory concentration of hymenoptaecin and to interact with the bacterial chaperone DnaK (an evolutionarily conserved central organizer of the bacterial chaperone network) when the membrane was compromised by hymenoptaecin. These naturally occurring potentiating interactions suggest that combinations of AMPs could be used therapeutically against Gram-negative bacterial pathogens that have acquired resistance to common antibiotics. PMID:25833860

  2. Antimicrobial peptides and their interaction with biofilms of medically relevant bacteria.

    Science.gov (United States)

    Batoni, Giovanna; Maisetta, Giuseppantonio; Esin, Semih

    2016-05-01

    Biofilm-associated infections represent one of the major threats of modern medicine. Biofilm-forming bacteria are encased in a complex mixture of extracellular polymeric substances (EPS) and acquire properties that render them highly tolerant to conventional antibiotics and host immune response. Therefore, there is a pressing demand of new drugs active against microbial biofilms. In this regard, antimicrobial peptides (AMPs) represent an option taken increasingly in consideration. After dissecting the peculiar biofilm features that may greatly affect the development of new antibiofilm drugs, the present article provides a general overview of the rationale behind the use of AMPs against biofilms of medically relevant bacteria and on the possible mechanisms of AMP-antibiofilm activity. An analysis of the interactions of AMPs with biofilm components, especially those constituting the EPS, and the obstacles and/or opportunities that may arise from such interactions in the development of new AMP-based antibiofilm strategies is also presented and discussed. This article is part of a Special Issue entitled: Antimicrobial Peptides edited by Karl Lohner and Kai Hilpert. PMID:26525663

  3. Expression of Antimicrobial Peptide Dybowskin-2CAMa in Pichia pastoris and Characterization of its Antibacterial Activity

    Directory of Open Access Journals (Sweden)

    Lili Jin

    2013-08-01

    Full Text Available In this study we used a yeast expression system to express a new antimicrobial peptide dybowskin-2CAMa from the skin cDNA library of Rana amurenisis. The entire coding region of the dybowskin-2CAMa was cloned into the plasmid pPICZ&alpha-A and then transformed into competent P. pastoris X33. The expressed dybowskin-2CAMa was purified from the culture supernatant by Sephadex G-25 and YMC*GEL ODS-A chromatography followed by C18 reverse phased HPLC. The purified peptide exhibited a single band of about 2 kDa when resolved by Tricine-SDS-PAGE. Its exact molecular weight was 2456.46 Da which was consistent with the value predicted from its deduced amino acid sequence. Antimicrobial activity assay showed that the recombinant dybowskin-2CAMa could inhibit the growth of a broad spectrum of bacteria, while displaying very low level of hemolytic activity (&le4% relative to Triton X-100, even at concentration of up to 500 &mug/mL.

  4. Vitamin D analogs differentially control antimicrobial peptide/"alarmin" expression in psoriasis.

    Directory of Open Access Journals (Sweden)

    Mark Peric

    Full Text Available Antimicrobial peptides (AMPs are strongly expressed in lesional skin in psoriasis and play an important role as proinflammatory "alarmins" in this chronic skin disease. Vitamin D analogs like calcipotriol have antipsoriatic effects and might mediate this effect by changing AMP expression. In this study, keratinocytes in lesional psoriatic plaques showed decreased expression of the AMPs beta-defensin (HBD 2 and HBD3 after topical treatment with calcipotriol. At the same time, calcipotriol normalized the proinflammatory cytokine milieu and decreased interleukin (IL-17A, IL-17F and IL-8 transcript abundance in lesional psoriatic skin. In contrast, cathelicidin antimicrobial peptide expression was increased by calcipotriol while psoriasin expression remained unchanged. In cultured human epidermal keratinocytes the effect of different vitamin D analogs on the expression of AMPs was further analyzed. All vitamin D analogs tested blocked IL-17A induced HBD2 expression by increasing IkappaB-alpha protein and inhibition of NF-kappaB signaling. At the same time vitamin D analogs induced cathelicidin through activation of the vitamin D receptor and MEK/ERK signaling. These studies suggest that vitamin D analogs differentially alter AMP expression in lesional psoriatic skin and cultured keratinocytes. Balancing AMP "alarmin" expression might be a novel goal in treatment of chronic inflammatory skin diseases.

  5. Liquid-crystalline ordering of antimicrobial peptide-DNA complexes controls TLR9 activation

    Science.gov (United States)

    Schmidt, Nathan W.; Jin, Fan; Lande, Roberto; Curk, Tine; Xian, Wujing; Lee, Calvin; Frasca, Loredana; Frenkel, Daan; Dobnikar, Jure; Gilliet, Michel; Wong, Gerard C. L.

    2015-07-01

    Double-stranded DNA (dsDNA) can trigger the production of type I interferon (IFN) in plasmacytoid dendritic cells (pDCs) by binding to endosomal Toll-like receptor-9 (TLR9; refs , , , , ). It is also known that the formation of DNA-antimicrobial peptide complexes can lead to autoimmune diseases via amplification of pDC activation. Here, by combining X-ray scattering, computer simulations, microscopy and measurements of pDC IFN production, we demonstrate that a broad range of antimicrobial peptides and other cationic molecules cause similar effects, and elucidate the criteria for amplification. TLR9 activation depends on both the inter-DNA spacing and the multiplicity of parallel DNA ligands in the self-assembled liquid-crystalline complex. Complexes with a grill-like arrangement of DNA at the optimum spacing can interlock with multiple TLR9 like a zipper, leading to multivalent electrostatic interactions that drastically amplify binding and thereby the immune response. Our results suggest that TLR9 activation and thus TLR9-mediated immune responses can be modulated deterministically.

  6. Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: II. Intestinal morphology and function.

    Science.gov (United States)

    Xiao, H; Tan, B E; Wu, M M; Yin, Y L; Li, T J; Yuan, D X; Li, L

    2013-10-01

    Deoxynivalenol (DON) affects animal and human health and targets the gastrointestinal tract. The objective of this study was to evaluate the ability of composite antimicrobial peptides (CAP) to repair intestinal injury in piglets challenged with DON. A total of 28 piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% composite antimicrobial peptide (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 mg/kg DON + 0.4% CAP (DON + CAP). After an adaptation period of 7 d, blood samples were collected on d 15 and 30 after the initiation of treatment for determinations of the concentrations of D-lactate and diamine oxidase. At the end of the study, all piglets were slaughtered to obtain small intestines for the determination of intestinal morphology, epithelial cell proliferation, and protein expression in the mammalian target of rapamycin (mTOR) signaling pathway. The results showed that DON increased serum concentrations of D-lactate and diamine oxidase, and these values in the CAP and DON + CAP treatments were less than those in the NC and DON treatments, respectively (P morphology and promoted intestinal epithelial cell proliferation and protein synthesis, indicating that CAP may repair the intestinal injury induced by DON.

  7. Insect antimicrobial peptides show potentiating functional interactions against Gram-negative bacteria.

    Science.gov (United States)

    Rahnamaeian, Mohammad; Cytryńska, Małgorzata; Zdybicka-Barabas, Agnieszka; Dobslaff, Kristin; Wiesner, Jochen; Twyman, Richard M; Zuchner, Thole; Sadd, Ben M; Regoes, Roland R; Schmid-Hempel, Paul; Vilcinskas, Andreas

    2015-05-01

    Antimicrobial peptides (AMPs) and proteins are important components of innate immunity against pathogens in insects. The production of AMPs is costly owing to resource-based trade-offs, and strategies maximizing the efficacy of AMPs at low concentrations are therefore likely to be advantageous. Here, we show the potentiating functional interaction of co-occurring insect AMPs (the bumblebee linear peptides hymenoptaecin and abaecin) resulting in more potent antimicrobial effects at low concentrations. Abaecin displayed no detectable activity against Escherichia coli when tested alone at concentrations of up to 200 μM, whereas hymenoptaecin affected bacterial cell growth and viability but only at concentrations greater than 2 μM. In combination, as little as 1.25 μM abaecin enhanced the bactericidal effects of hymenoptaecin. To understand these potentiating functional interactions, we investigated their mechanisms of action using atomic force microscopy and fluorescence resonance energy transfer-based quenching assays. Abaecin was found to reduce the minimal inhibitory concentration of hymenoptaecin and to interact with the bacterial chaperone DnaK (an evolutionarily conserved central organizer of the bacterial chaperone network) when the membrane was compromised by hymenoptaecin. These naturally occurring potentiating interactions suggest that combinations of AMPs could be used therapeutically against Gram-negative bacterial pathogens that have acquired resistance to common antibiotics.

  8. Lipopolysaccharide neutralization by antimicrobial peptides: a gambit in the innate host defense strategy.

    Science.gov (United States)

    Pulido, David; Nogués, M Victòria; Boix, Ester; Torrent, Marc

    2012-01-01

    Antimicrobial peptides (AMPs) are nowadays understood as broad multifunctional tools of the innate immune system to fight microbial infections. In addition to its direct antimicrobial action, AMPs can modulate the host immune response by promoting or restraining the recruitment of cells and chemicals to the infection focus. Binding of AMPs to lipopolysaccharide is a critical step for both their antimicrobial action and their immunomodulatory properties. On the one hand, removal of Gram-negative bacteria by AMPs can be an effective strategy to prevent a worsened inflammatory response that may lead to septic shock. On the other hand, by neutralizing circulating endotoxins, AMPs can successfully reduce nitric oxide and tumor necrosis factor-α production, hence preventing severe tissue damage. Furthermore, AMPs can also interfere with the Toll-like receptor 4 recognition system, suppressing cytokine production and contributing to modulate the inflammatory response. Here, we review the immune system strategies devised by AMPs to avoid an exacerbated inflammatory response and thus prevent a fatal end to the host.

  9. A Complete Lipopolysaccharide Inner Core Oligosaccharide Is Required for Resistance of Burkholderia cenocepacia to Antimicrobial Peptides and Bacterial Survival In Vivo

    OpenAIRE

    Loutet, Slade A.; Flannagan, Ronald S.; Kooi, Cora; Sokol, Pamela A.; Valvano, Miguel A

    2006-01-01

    Burkholderia cenocepacia is an important opportunistic pathogen of patients with cystic fibrosis. This bacterium is inherently resistant to a wide range of antimicrobial agents, including high concentrations of antimicrobial peptides. We hypothesized that the lipopolysaccharide (LPS) of B. cenocepacia is important for both virulence and resistance to antimicrobial peptides. We identified hldA and hldD genes in B. cenocepacia strain K56-2. These two genes encode enzymes involved in the modific...

  10. New semisynthetic antimicrobial labdane-type diterpenoids derived from the resin "ladano" of Cistus creticus.

    Science.gov (United States)

    Kalpoutzakis, E; Aligiannis, N; Mitaku, S; Chinou, I; Harvala, C; Skaltsounis, A L

    2001-01-01

    The antimicrobial activity of fifteen semisynthetic labdane-type diterpenes derived from the two major natural compounds 3 and 4 of the resin "ladano" of Cistus creticus is reported. The chloroethyl carbamidic esters 15 and 20 showed the strongest antimicrobial activity against Gram(+), Gram(-) bacteria and pathogenic fungi. PMID:11302213

  11. Macrobrachium rosenbergii mannose binding lectin: synthesis of MrMBL-N20 and MrMBL-C16 peptides and their antimicrobial characterization, bioinformatics and relative gene expression analysis.

    Science.gov (United States)

    Arockiaraj, Jesu; Chaurasia, Mukesh Kumar; Kumaresan, Venkatesh; Palanisamy, Rajesh; Harikrishnan, Ramasamy; Pasupuleti, Mukesh; Kasi, Marimuthu

    2015-04-01

    is involved in antimicrobial mechanism. Moreover, MrMBL derived MrMBL-N20 and MrMBL-C16 peptides are important antimicrobial peptides for the recognition and eradication of viral and bacterial pathogens.

  12. Saturation mutagenesis of lysine 12 leads to the identification of derivatives of nisin A with enhanced antimicrobial activity.

    Directory of Open Access Journals (Sweden)

    Evelyn M Molloy

    Full Text Available It is becoming increasingly apparent that innovations from the "golden age" of antibiotics are becoming ineffective, resulting in a pressing need for novel therapeutics. The bacteriocin family of antimicrobial peptides has attracted much attention in recent years as a source of potential alternatives. The most intensively studied bacteriocin is nisin, a broad spectrum lantibiotic that inhibits gram-positive bacteria including important food pathogens and clinically relevant antibiotic resistant bacteria. Nisin is gene-encoded and, as such, is amenable to peptide bioengineering, facilitating the generation of novel derivatives that can be screened for desirable properties. It was to this end that we used a site-saturation mutagenesis approach to create a bank of producers of nisin A derivatives that differ with respect to the identity of residue 12 (normally lysine; K12. A number of these producers exhibited enhanced bioactivity and the nisin A K12A producer was deemed of greatest interest. Subsequent investigations with the purified antimicrobial highlighted the enhanced specific activity of this modified nisin against representative target strains from the genera Streptococcus, Bacillus, Lactococcus, Enterococcus and Staphylococcus.

  13. Recombinant expression and solution structure of antimicrobial peptide aurelin from jellyfish Aurelia aurita

    International Nuclear Information System (INIS)

    Highlights: ► Aurelin was overexpressed in Escherichia coli, and its spatial structure was studied by NMR. ► Aurelin compact structure encloses helical regions cross-linked by three disulfide bonds. ► Aurelin shows structural homology to the BgK and ShK toxins of sea anemones. ► Aurelin binds to the anionic lipid vesicles, but does not interact with zwitterionic ones. ► Aurelin binds to DPC micelle surface with moderate affinity via two helical regions. -- Abstract: Aurelin is a 40-residue cationic antimicrobial peptide isolated from the mezoglea of a scyphoid jellyfish Aurelia aurita. Aurelin and its 15N-labeled analogue were overexpressed in Escherichia coli and purified. Antimicrobial activity of the recombinant peptide was examined, and its spatial structure was studied by NMR spectroscopy. Aurelin represents a compact globule, enclosing one 310-helix and two α-helical regions cross-linked by three disulfide bonds. The peptide binds to anionic lipid (POPC/DOPG, 3:1) vesicles even at physiological salt concentration, it does not interact with zwitterionic (POPC) vesicles and interacts with the DPC micelle surface with moderate affinity via two α-helical regions. Although aurelin shows structural homology to the BgK and ShK toxins of sea anemones, its surface does not possess the “functional dyad” required for the high-affinity interaction with the K+-channels. The obtained data permit to correlate the modest antibacterial properties and membrane activity of aurelin.

  14. IL-10 inhibits while calcitriol reestablishes placental antimicrobial peptides gene expression.

    Science.gov (United States)

    Olmos-Ortiz, Andrea; Noyola-Martínez, Nancy; Barrera, David; Zaga-Clavellina, Verónica; Avila, Euclides; Halhali, Ali; Biruete, Benjamín; Larrea, Fernando; Díaz, Lorenza

    2015-04-01

    IL-10 and calcitriol help to achieve a successful pregnancy by suppressing active maternal immunity; however, these factors exert opposite effects upon microbial infections. In the skin and immune cells, IL-10 downregulates β-defensins while calcitriol induces cathelicidin gene expression in various tissues including placenta. Though, the regulation of human placental β-defensins by IL-10 and calcitriol has not been studied. Therefore, we explored the regulation of these antimicrobial peptides expression in cultured placental cells by calcitriol and IL-10 alone and combined. Real time PCR showed that calcitriol stimulated, while IL-10 inhibited, β-defensins and cathelicidin gene expression (Pantimicrobial peptides gene expression above control values, overriding IL-10 inhibitory effects. Calcitriol downregulated endogenous IL-10 secretion. Interestingly, calcitriol and TNF-α cooperatively enhanced β-defensins, while TNF-α reduced basal and calcitriol-stimulated cathelicidin gene expression. In summary, calcitriol and IL-10 exerted opposite effects on antimicrobial peptides expression in the human placenta, suggesting that unbalanced production of IL-10 and calcitriol could be deleterious to innate immune responses during gestation. Our results suggest that calcitriol enhancement of placental defenses involves two mechanisms: (1) downregulation of IL-10 secretion and (2) direct upregulation of β-defensins and cathelicidin gene expression. Considering that IL-10 and calcitriol differentially regulate the innate immune response in the placenta, in the case of an infection, calcitriol might restrict IL-10 permissive actions towards microbial invasion while restrains inflammation, allowing for pregnancy to continue in quiescence. These results strongly advice maternal vitamin D sufficiency during pregnancy.

  15. Enhancement of cytotoxicity of antimicrobial peptide magainin Ⅱ in tumor cells by bombesin-targeted delivery

    Institute of Scientific and Technical Information of China (English)

    Shan LIU; Hao YANG; Lin WAN; Hua-wei CAI; Sheng-fu LI; You-ping LI; Jing-qiu CHENG; Xiao-feng LU

    2011-01-01

    Aim: To investigate whether the conjugation of magainin II(MG2),an antimicrobial peptides(AMPs),to the tumor-homing peptide bombesin could enhance its cytotoxicity in tumor cells.Methods: A magainin Ⅱ-bombesin conjugate(MG2B)was constructed by attaching magainin Ⅱ(MG2)to bombesin at its N-terminus.The peptides were synthesized using Fmoc-chemistry.The in vitro cytotoxicity of the peptide in cancer cells was quantitatively determined using the CCK-8 celt counting kit.Moreover,the in vivo antitumor effect of the peptide was determined in tumor xenograft models.Results: The IC50 of MG2B for cancer cells(10-15 μmol/L)was at least 10 times lower than the IC50 of unconjugated MG2(125μmol/L).Moreover,the binding affinity of MG2B for cancer cells was higher than that of unconjugated MG2.In contrast,conjugation to a bombesin analog lacking the receptor-binding domain failed to increase the cytotoxicity of MG2,suggesting that bombesin conjugation enhances the cytotoxicity of MG2 in cancer cells through improved binding.Indeed,MG2B selectively induced cell death in cancer cells in vitro with the IC50 ranging from 10 to 15 μmol/L,which was about 6-10 times lower than the IC50 for normal cells.MG2B(20mg/kg per day,intratumorally injected for 5 d)also exhibited antitumor effects in mice bearing MCF-7 tumor grafts.The mean weights of tumor grafts in MG2B-and PBS-treated mice were 0.21±0.05 g and 0.59±0.12 g,respectively.Conclusion: The results suggest that conjugation of AMPs to bombesin might be an alternative approach for targeted cancer therapy.

  16. Purification of antimicrobial peptide from Antarctic Krill ( Euphausia superba) and its function mechanism

    Science.gov (United States)

    Zhao, Ling; Yin, Bangzhong; Liu, Qi; Cao, Rong

    2013-09-01

    The preliminary purification and antimicrobial mechanism of antimicrobial peptide from Antarctic Krill were studied in this paper. The results showed that the molecular weight range of antimicrobial polypeptide (CMCC-1) obtained by cation exchange chromatography was between 245-709D as detected by molecular sieve chromatography, and the minimum inhibition concentration (MIC) of CMCC-1 against Staphylococcus aureus was 5.0 mg mL-1. The antimicrobial mechanism of CMCC-1 was studied with S. aureus as indicator bacterium. Compared with control group, the results of the experimental group in which S. aureus was treated with CMCC-1 were as follows: 1) CMCC-1 could inhibit cell division at logarithmic phase. 2) The protein and reducing sugar content, and the conductivity of culture medium increased, and the activity of alkaline phosphatase and β-galactosidase could be detected in the culture medium. 3) Observation under scanning electron microscope revealed that somatic morphology became irregular, and then somatic surface became coarse. The cell became much smaller, and most somatic cells gathered. The boundary between cells became dim and finally fused as a whole. 4) Observation under transmission electron microscope showed that the surface of S. aureus became rough and the reproducing ability was restrained. The cell wall became thin and the cytoplasm shrunk. Substances inside cell leaked out, which caused cells death. 5) SDS-PAGE analysis showed that some bands disappeared, and the residual bands became vague. 6) The genomic DNA electrophoresis results showed that the genomic DNA bands of S. aureus were not degraded but the brightness significantly reduced. Thus, it is supposed that CMCC-1 could destroy the cell wall and membrane of S. aureu, increase the cell membrane permeability and the leaking-out of intracellular substances, and thus cause the death of S. aureu.

  17. Purification of Antimicrobial Peptide from Antarctic Krill (Euphausia superba) and its Function Mechanism

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ling; YIN Bangzhong; LIU Qi; CAO Rong

    2013-01-01

    The preliminary purification and antimicrobial mechanism of antimicrobial peptide from Antarctic Krill were studied in this paper.The results showed that the molecular weight range of antimicrobial polypeptide (CMCC-1) obtained by cation exchange chromatography was between 245-709D as detected by molecular sieve chromatography,and the minimum inhibition concentration (MIC) of CMCC-1 against Staphylococcus aureus was 5.0mgmL-1.The antimicrobial mechanism of CMCC-1 was studied with S.aureus as indicator bacterium.Compared with control group,the results of the experimental group in which S.aureus was treated with CMCC-1 were as follows:1) CMCC-1 could inhibit cell division at logarithmic phase.2) The protein and reducing sugar content,and the conductivity of culture medium increased,and the activity of alkaline phosphatase and β-galactosidase could be detected in the culture medium.3) Observation under scanning electron microscope revealed that somatic morphology became irregular,and then somatic surface became coarse.The cell became much smaller,and most somatic cells gathered.The boundary between cells became dim and finally fused as a whole.4) Observation under transmission electron microscope showed that the surface of S.aureus became rough and the reproducing ability was restrained.The cell wall became thin and the cytoplasm shrunk.Substances inside cell leaked out,which caused cells death.5) SDS-PAGE analysis showed that some bands disappeared,and the residual bands became vague.6) The genomic DNA electrophoresis results showed that the genomic DNA bands ofS.aureus were not degraded but the brightness significantly reduced.Thus,it is supposed that CMCC-1 could destroy the cell wall and membrane of S.aureu,increase the cell membrane permeability and the leaking-out of intracellular substances,and thus cause the death of S.aureu.

  18. A fossil antibacterial peptide gives clues to structural diversity of cathelicidin-derived host defense peptides.

    Science.gov (United States)

    Zhu, Shunyi; Gao, Bin

    2009-01-01

    Cathelicidins, a group of vertebrate- specific immune effector molecules, developed into a multigene family through gene duplication in the Cetartiodactyla lineage, in which structural changes of the antimicrobial domains (AMDs) among paralogs during evolution are clearly associated with functional diversification of cathelicidins. However, the evolutionary mechanism for such structural diversity remains largely unsolved. Although at the genomic level, the 3'-exon alone encoding the variable AMD repertoire would favor a role of exon shuffling, the observation that two structurally unrelated subfamilies of AMDs (protegrins and prophenins) display high similarity in some nucleotide regions of the 3'-exons of their genes provides evidence for postduplication sequence remodeling. This opinion is further strengthened by finding a proline-arginine-rich antibacterial peptide of 38 residues (named PR-38) encoded by an open reading frame located in the 3' untranslated region of protegrins, which is in frame with prophenins. The latter appears to have undergone internal motif repeats in the region corresponding to PR-38. PR-38 exhibits similar amino acid sequence and carboxyl-terminal amidation feature to PR-39s, a subfamily of cathelicidin peptides conserved across Cetartiodactyla. Functional assays of the chemically synthesized PR-38 confirmed its antibacterial activity with a similar action mode to PR-39 against both gram-positive and gram-negative bacteria at micromolar concentrations, supporting an ancient functional link among cathelicidin members belonging to different subfamilies. Resurrecting the fossil peptide highlights the evolutionary position of PR-39 in generating structurally variable subfamilies of porcine cathelicidins through postduplication sequence remodeling. PMID:18796560

  19. AaeAP1 and AaeAP2: Novel Antimicrobial Peptides from the Venom of the Scorpion, Androctonus aeneas: Structural Characterisation, Molecular Cloning of Biosynthetic Precursor-Encoding cDNAs and Engineering of Analogues with Enhanced Antimicrobial and Anticancer Activities

    Directory of Open Access Journals (Sweden)

    Qiang Du

    2015-01-01

    Full Text Available The main functions of the abundant polypeptide toxins present in scorpion venoms are the debilitation of arthropod prey or defence against predators. These effects are achieved mainly through the blocking of an array of ion channel types within the membranes of excitable cells. However, while these ion channel-blocking toxins are tightly-folded by multiple disulphide bridges between cysteine residues, there are additional groups of peptides in the venoms that are devoid of cysteine residues. These non-disulphide bridged peptides are the subject of much research interest, and among these are peptides that exhibit antimicrobial activity. Here, we describe two novel non-disulphide-bridged antimicrobial peptides that are present in the venom of the North African scorpion, Androctonus aeneas. The cDNAs encoding the biosynthetic precursors of both peptides were cloned from a venom-derived cDNA library using 3'- and 5'-RACE strategies. Both translated precursors contained open-reading frames of 74 amino acid residues, each encoding one copy of a putative novel nonadecapeptide, whose primary structures were FLFSLIPSVIAGLVSAIRN and FLFSLIPSAIAGLVSAIRN, respectively. Both peptides were C-terminally amidated. Synthetic versions of each natural peptide displayed broad-spectrum antimicrobial activities, but were devoid of antiproliferative activity against human cancer cell lines. However, synthetic analogues of each peptide, engineered for enhanced cationicity and amphipathicity, exhibited increases in antimicrobial potency and acquired antiproliferative activity against a range of human cancer cell lines. These data clearly illustrate the potential that natural peptide templates provide towards the design of synthetic analogues for therapeutic exploitation.

  20. Synthetic amphibian peptides and short amino-acids derivatives against planktonic cells and mature biofilm of Providencia stuartii clinical strains.

    Science.gov (United States)

    Ostrowska, Kinga; Kamysz, Wojciech; Dawgul, Małgorzata; Różalski, Antoni

    2014-01-01

    Over the last decade, the growing number of multidrug resistant strains limits the use of many of the currently available chemotherapeutic agents. Furthermore, bacterial biofilm, due to its complex structure, constitutes an effective barrier to conventional antibiotics. The in vitro activities of naturally occurring peptide (Citropin 1.1), chemically engineered analogue (Pexiganan), newly-designed, short amino-acid derivatives (Pal-KK-NH2, Pal-KKK-NH2, Pal-RRR-NH2) and six clinically used antimicrobial agents (Gatifloxacin, Ampicilin, Cefotaxime, Ceftriaxone, Cefuroxime and Cefalexin) were investigated against planktonic cells and mature biofilm of multidrug-resistant Providencia stuartii strains, isolated from urological catheters. The MICs, MBCs values were determined by broth microdilution technique. Inhibition of biofilm formation by antimicrobial agents as well as biofilm susceptibility assay were tested using a surrogate model based on the Crystal Violet method. The antimicrobial activity of amino-acids derivatives and synthetic peptides was compared to that of clinically used antibiotics. For planktonic cells, MICs of peptides and antibiotics ranged between 1 and 256 μg/ml and 256 and ≥ 2048 μg/ml, respectively. The MBCs values of Pexiganan, Citropin 1.1 and amino-acids derivatives were between 16 and 256 μg/ml, 64 and 256 μg/ml and 16 and 512 μg/ml, respectively. For clinically used antibiotics the MBCs values were above 2048 μg/ml. All of the tested peptides and amino-acids derivatives, showed inhibitory activity against P. stuartii biofilm formation, in relation to their concentrations. Pexiganan and Citropin 1.1 in concentration range 32 and 256 μg/ml caused both strong and complete suppression of biofilm formation. None of the antibiotics caused complete inhibition of biofilm formation process. The biofilm susceptibility assay verified the extremely poor antibiofilm activity of conventional antibiotics compared to synthetic peptides. The

  1. Antimicrobial peptide production and plant-based expression systems for medical and agricultural biotechnology.

    Science.gov (United States)

    Holaskova, Edita; Galuszka, Petr; Frebort, Ivo; Oz, M Tufan

    2015-11-01

    Antimicrobial peptides (AMPs) are vital components of the innate immune system of nearly all living organisms. They generally act in the first line of defense against various pathogenic bacteria, parasites, enveloped viruses and fungi. These low molecular mass peptides are considered prospective therapeutic agents due to their broad-spectrum rapid activity, low cytotoxicity to mammalian cells and unique mode of action which hinders emergence of pathogen resistance. In addition to medical use, AMPs can also be employed for development of innovative approaches for plant protection in agriculture. Conferred disease resistance by AMPs might help us surmount losses in yield, quality and safety of agricultural products due to plant pathogens. Heterologous expression in plant-based systems, also called plant molecular farming, offers cost-effective large-scale production which is regarded as one of the most important factors for clinical or agricultural use of AMPs. This review presents various types of AMPs as well as plant-based platforms ranging from cell suspensions to whole plants employed for peptide production. Although AMP production in plants holds great promises for medicine and agriculture, specific technical limitations regarding product yield, function and stability still remain. Additionally, establishment of particular stable expression systems employing plants or plant tissues generally requires extended time scale for platform development compared to certain other heterologous systems. Therefore, fast and promising tools for evaluation of plant-based expression strategies and assessment of function and stability of the heterologously produced AMPs are critical for molecular farming and plant protection.

  2. BaAMPs: the database of biofilm-active antimicrobial peptides.

    Science.gov (United States)

    Di Luca, Mariagrazia; Maccari, Giuseppe; Maisetta, Giuseppantonio; Batoni, Giovanna

    2015-01-01

    Antimicrobial peptides (AMPs) are increasingly being considered as novel agents against biofilms. The development of AMP-based anti-biofilm strategies strongly relies on the design of sequences optimized to target specific features of sessile bacterial/fungal communities. Although several AMP databases have been created and successfully exploited for AMP design, all of these use data collected on peptides tested against planktonic microorganisms. Here, an open-access, manually curated database of AMPs specifically assayed against microbial biofilms (BaAMPs) is presented for the first time. In collecting relevant data from the literature an effort was made to define a minimal standard set of essential information including, for each AMP, the microbial species and biofilm conditions against which it was tested, and the specific assay and peptide concentration used. The availability of these data in an organized framework will benefit anti-biofilm research and support the design of novel molecules active against biofilm. BaAMPs is accessible at http://www.baamps.it. PMID:25760404

  3. Assessment of antimicrobial (host defense) peptides as anti-cancer agents.

    Science.gov (United States)

    Douglas, Susan; Hoskin, David W; Hilchie, Ashley L

    2014-01-01

    Cationic antimicrobial (host defense) peptides (CAPs) are able to kill microorganisms and cancer cells, leading to their consideration as novel candidate therapeutic agents in human medicine. CAPs can physically associate with anionic membrane structures, such as those found on cancer cells, causing pore formation, intracellular disturbances, and leakage of cell contents. In contrast, normal cells are less negatively-charged and are typically not susceptible to CAP-mediated cell death. Because the interaction of CAPs with cells is based on charge properties rather than cell proliferation, both rapidly dividing and quiescent cancer cells, as well as multidrug-resistant cancer cells, are targeted by CAPs, making CAPS potentially valuable as anti-cancer agents. CAPs often exist as families of peptides with slightly different amino acid sequences. In addition, libraries of synthetic peptide variants based on naturally occurring CAP templates can be generated in order to improve upon their action. High-throughput screens are needed to quickly and efficiently assess the suitability of each CAP variant. Here we present the methods for assessing CAP-mediated cytotoxicity against cancer cells (suspension and adherent) and untransformed cells (measured using the tritiated thymidine-release or MTT assay), and for discriminating between cell death caused by necrosis (measured using lactate dehydrogenase- or (51)Cr-release assays), or apoptosis and necrosis (single-stranded DNA content measured by flow cytometry). In addition the clonogenic assay, which assesses the ability of single transformed cells to multiply and produce colonies, is described.

  4. Prediction of Leymus arenarius (L.) antimicrobial peptides based on de novo transcriptome assembly.

    Science.gov (United States)

    Slavokhotova, Anna A; Shelenkov, Andrey A; Odintsova, Tatyana I

    2015-10-01

    Leymus arenarius is a unique wild growing Poaceae plant exhibiting extreme tolerance to environmental conditions. In this study we for the first time performed whole-transcriptome sequencing of lymegrass seedlings using Illumina platform followed by de novo transcriptome assembly and functional annotation. Our goal was to identify transcripts encoding antimicrobial peptides (AMPs), one of the key components of plant innate immunity. Using the custom software developed for this study that predicted AMPs and classified them into families, we revealed more than 160 putative AMPs in lymegrass seedlings. We classified them into 7 families based on their cysteine motifs and sequence similarity. The families included defensins, thionins, hevein-like peptides, snakins, cyclotide, alfa-hairpinins and LTPs. This is the first communication about the presence of almost all known AMP families in trascriptomic data of a single plant species. Additionally, cysteine-rich peptides that potentially represent novel families of AMPs were revealed. We have confirmed by RT-PCR validation the presence of 30 transcripts encoding selected AMPs in lymegrass seedlings. In summary, the presented method of pAMP prediction developed by us can be applied for relatively fast and simple screening of novel components of plant immunity system and is well suited for whole-transcriptome or genome analysis of uncharacterized plants. PMID:26369913

  5. Antimicrobial Peptides: Their Role as Infection-Selective Tracers for Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Thomas Ebenhan

    2014-01-01

    Full Text Available Antimicrobial peptides (AMPs are a heterogeneous class of compounds found in a variety of organisms including humans and, so far, hundreds of these structures have been isolated and characterised. They can be described as natural microbicide, selectively cytotoxic to bacteria, whilst showing minimal cytotoxicity towards the mammalian cells of the host organism. They act by their relatively strong electrostatic attraction to the negatively charged bacterial cells and a relatively weak interaction to the eukaryote host cells. The ability of these peptides to accumulate at sites of infection combined with the minimal host’s cytotoxicity motivated for this review to highlight the role and the usefulness of AMPs for PET with emphasis on their mechanism of action and the different interactions with the bacterial cell. These details are key information for their selective properties. We also describe the strategy, design, and utilization of these peptides as potential radiopharmaceuticals as their combination with nuclear medicine modalities such as SPECT or PET would allow noninvasive whole-body examination for detection of occult infection causing, for example, fever of unknown origin.

  6. Prokaryotic Selectivity, Anti-endotoxic Activity and Protease Stability of Diastereomeric and Enantiomeric Analogs of Human Antimicrobial Peptide LL-37

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Yong Hai; Lee, Bongju; Shin, Song Yub [Chosun Univ., Gwangju (Korea, Republic of)

    2012-09-15

    LL-37 is the only antimicrobial peptide (AMP) of the human cathelicidin family. In addition to potent antimicrobial activity, LL-37 is known to have the potential to inhibit lipolysaccharide (LPS)-induced endotoxic effects. To provide the stability to proteolytic digestion and increase prokaryotic selectivity and/or anti-endotoxic activity of two Lys/Trp-substituted 19-meric anti-microbial peptides (a4-W1 and a4-W2) designed from IG-19 (residues 13-31 of LL-37), we synthesized the diastereomeric peptides (a4-W1-D and a4-W2-D) with D-amino acid substitution at positions 3, 7, 10, 13 and 17 of a4-W1 and a4-W2, respectively and the enantiomeric peptides (a4-W1-E and a4-W2-E) composed D-amino acids. The diastereomeric peptides exhibited the best prokaryotic selectivity and effective protease stability, but no or less anti-endotoxic activity. In contrast, the enantiomeric peptides had not only prokaryotic selectivity and anti-endotoxic activity but also protease stability. Our results suggest that the hydrophobicity and α-helicity of the peptide is important for anti-endotoxic activity. In particular, the enantiomeric peptides showed potent anti-endotoxic and LPS-neutralizing activities comparable to that of LL-37. Taken together, both a4-W1-E and a4-W2-E holds promise as a template for the development of peptide antibiotics for the treatment of endotoxic shock and sepsis.

  7. Synthesis and Antimicrobial Evaluation of Some Heterocyclic Chalcone Derivatives

    Directory of Open Access Journals (Sweden)

    Essam Mohamed Sharshira

    2011-03-01

    Full Text Available Some new heterocyclic compounds containing isoxazole, pyrazole and oxadiazole ring systems were prepared from various chalcones. The synthesized compounds have been characterized by elemental analysis and spectral methods. These compounds were screened for their antimicrobial activities.

  8. Synthesis and Antimicrobial Evaluation of Some Heterocyclic Chalcone Derivatives

    OpenAIRE

    Essam Mohamed Sharshira; Nagwa Mohamed Mahrous Hamada

    2011-01-01

    Some new heterocyclic compounds containing isoxazole, pyrazole and oxadiazole ring systems were prepared from various chalcones. The synthesized compounds have been characterized by elemental analysis and spectral methods. These compounds were screened for their antimicrobial activities.

  9. Novel method to identify the optimal antimicrobial peptide in a combination matrix, using anoplin as an example

    DEFF Research Database (Denmark)

    Munk, Jens; Ritz, Christian; Fliedner, Frederikke Petrine;

    2014-01-01

    Microbial resistance is an increasing health concern and a true danger to human wellbeing. A worldwide search for new compounds is ongoing and antimicrobial peptides are promising lead candidates for tomorrow's antibiotics. The decapeptide anoplin, GLLKRIKTLL-NH2, is an especially interesting can...

  10. Activation of phospholipase A2 by temporin B: Formation of antimicrobial peptide-enzyme amyloid-type cofibrils

    NARCIS (Netherlands)

    Code, Christian; Domanov, Y.A.; Killian, J.A.; Kinnunen, P.K.J.

    2009-01-01

    Phospholipases A2 have been shown to be activated in a concentration dependent manner by a number of antimicrobial peptides, including melittin, magainin 2, indolicidin, and temporins B and L. Here we used fluorescently labelled bee venom PLA2 (PLA2D) and the saturated phospholipid substrate 1,2-dip

  11. Characterization of virus/double-stranded RNA-dependent induction of antimicrobial peptide hepcidin in trout macrophages

    Science.gov (United States)

    Hepcidin is an antimicrobial peptide responsive to bacterial infection. We report the characterization of a virus/doublestranded RNA (dsRNA) induction of hepcidin in rainbow trout (Oncorhynchus mykiss). Increased level of hepcidin mRNA was observed in trout macrophage RTS11 cells treated with poly...

  12. Expression of an antimicrobial peptide, digestive enzymes and nutrient transporters in the intestine of E. praecox-infected chickens

    Science.gov (United States)

    Coccidiosis is a major intestinal disease of poultry, caused by several species of the protozoan Eimeria. The objective of this study was to examine changes in expression of digestive enzymes, nutrient transporters and an antimicrobial peptide following an Eimeria praecox challenge of chickens at d...

  13. The negatively charged regions of lactoferrin binding protein B, an adaptation against anti-microbial peptides.

    Directory of Open Access Journals (Sweden)

    Ari Morgenthau

    Full Text Available Lactoferrin binding protein B (LbpB is a bi-lobed membrane bound lipoprotein that is part of the lactoferrin receptor complex in a variety of Gram-negative pathogens. Despite high sequence diversity among LbpBs from various strains and species, a cluster of negatively charged amino acids is invariably present in the protein's C-terminal lobe in all species except Moraxella bovis. The function of LbpB in iron acquisition has yet to be experimentally demonstrated, whereas in vitro studies have shown that LbpB confers protection against lactoferricin, a short cationic antimicrobial peptide released from the N- terminus of lactoferrin. In this study we demonstrate that the negatively charged regions can be removed from the Neisseria meningitidis LbpB without compromising stability, and this results in the inability of LbpB to protect against the bactericidal effects of lactoferricin. The release of LbpB from the cell surface by the autotransporter NalP reduces the protection against lactoferricin in the in vitro killing assay, attributed to removal of LbpB during washing steps, but is unlikely to have a similar impact in vivo. The protective effect of the negatively charged polysaccharide capsule in the killing assay was less than the protection conferred by LbpB, suggesting that LbpB plays a major role in protection against cationic antimicrobial peptides in vivo. The selective release of LbpB by NalP has been proposed to be a mechanism for evading the adaptive immune response, by reducing the antibody binding to the cell surface, but may also provide insights into the primary function of LbpB in vivo. Although TbpB and LbpB have been shown to be major targets of the human immune response, the selective release of LbpB suggests that unlike TbpB, LbpB may not be essential for iron acquisition, but important for protection against cationic antimicrobial peptides.

  14. The negatively charged regions of lactoferrin binding protein B, an adaptation against anti-microbial peptides.

    Science.gov (United States)

    Morgenthau, Ari; Beddek, Amanda; Schryvers, Anthony B

    2014-01-01

    Lactoferrin binding protein B (LbpB) is a bi-lobed membrane bound lipoprotein that is part of the lactoferrin receptor complex in a variety of Gram-negative pathogens. Despite high sequence diversity among LbpBs from various strains and species, a cluster of negatively charged amino acids is invariably present in the protein's C-terminal lobe in all species except Moraxella bovis. The function of LbpB in iron acquisition has yet to be experimentally demonstrated, whereas in vitro studies have shown that LbpB confers protection against lactoferricin, a short cationic antimicrobial peptide released from the N- terminus of lactoferrin. In this study we demonstrate that the negatively charged regions can be removed from the Neisseria meningitidis LbpB without compromising stability, and this results in the inability of LbpB to protect against the bactericidal effects of lactoferricin. The release of LbpB from the cell surface by the autotransporter NalP reduces the protection against lactoferricin in the in vitro killing assay, attributed to removal of LbpB during washing steps, but is unlikely to have a similar impact in vivo. The protective effect of the negatively charged polysaccharide capsule in the killing assay was less than the protection conferred by LbpB, suggesting that LbpB plays a major role in protection against cationic antimicrobial peptides in vivo. The selective release of LbpB by NalP has been proposed to be a mechanism for evading the adaptive immune response, by reducing the antibody binding to the cell surface, but may also provide insights into the primary function of LbpB in vivo. Although TbpB and LbpB have been shown to be major targets of the human immune response, the selective release of LbpB suggests that unlike TbpB, LbpB may not be essential for iron acquisition, but important for protection against cationic antimicrobial peptides. PMID:24465982

  15. The antimicrobial activity of lapachol and its thiosemicarbazone and semicarbazone derivatives

    OpenAIRE

    Marina Azevedo Souza; Susana Johann; Luciana Alves Rodrigues dos Santos Lima; Fernanda Fraga Campos; Isolda Castro Mendes; Heloisa Beraldo; Elaine Maria de Souza-Fagundes; Patricia Silva Cisalpino; Carlos Augusto Rosa; Tania Maria de Almeida Alves; Nivea Pereira de Sa; Carlos Leomar Zani

    2013-01-01

    Lapachol was chemically modified to obtain its thiosemicarbazone and semicarbazone derivatives. These compounds were tested for antimicrobial activity against several bacteria and fungi by the broth microdilution method. The thiosemicarbazone and semicarbazone derivatives of lapachol exhibited antimicrobial activity against the bacteria Enterococcus faecalis and Staphylococcus aureus with minimal inhibitory concentrations (MICs) of 0.05 and 0.10 µmol/mL, respectively. The thiosemicarbazone an...

  16. The antimicrobial activity of lapachol and its thiosemicarbazone and semicarbazone derivatives

    OpenAIRE

    2013-01-01

    Lapachol was chemically modified to obtain its thiosemicarbazone and semicarbazone derivatives. These compounds were tested for antimicrobial activity against several bacteria and fungi by the broth microdilution method. The thiosemicarbazone and semicarbazone derivatives of lapachol exhibited antimicrobial activity against the bacteria Enterococcus faecalis and Staphylococcus aureus with minimal inhibitory concentrations (MICs) of 0.05 and 0.10 µmol/mL, respectively. The thiosemicarbazo...

  17. Identification of a novel antimicrobial peptide from human hepatitis B virus core protein arginine-rich domain (ARD.

    Directory of Open Access Journals (Sweden)

    Heng-Li Chen

    Full Text Available The rise of multidrug-resistant (MDR pathogens causes an increasing challenge to public health. Antimicrobial peptides are considered a possible solution to this problem. HBV core protein (HBc contains an arginine-rich domain (ARD at its C-terminus, which consists of 16 arginine residues separated into four clusters (ARD I to IV. In this study, we demonstrated that the peptide containing the full-length ARD I-IV (HBc147-183 has a broad-spectrum antimicrobial activity at micro-molar concentrations, including some MDR and colistin (polymyxin E-resistant Acinetobacter baumannii. Furthermore, confocal fluorescence microscopy and SYTOX Green uptake assay indicated that this peptide killed Gram-negative and Gram-positive bacteria by membrane permeabilization or DNA binding. In addition, peptide ARD II-IV (HBc153-176 and ARD I-III (HBc147-167 were found to be necessary and sufficient for the activity against P. aeruginosa and K. peumoniae. The antimicrobial activity of HBc ARD peptides can be attenuated by the addition of LPS. HBc ARD peptide was shown to be capable of direct binding to the Lipid A of lipopolysaccharide (LPS in several in vitro binding assays. Peptide ARD I-IV (HBc147-183 had no detectable cytotoxicity in various tissue culture systems and a mouse animal model. In the mouse model by intraperitoneal (i.p. inoculation with Staphylococcus aureus, timely treatment by i.p. injection with ARD peptide resulted in 100-fold reduction of bacteria load in blood, liver and spleen, as well as 100% protection of inoculated animals from death. If peptide was injected when bacterial load in the blood reached its peak, the protection rate dropped to 40%. Similar results were observed in K. peumoniae using an IVIS imaging system. The finding of anti-microbial HBc ARD is discussed in the context of commensal gut microbiota, development of intrahepatic anti-viral immunity and establishment of chronic infection with HBV. Our current results suggested that

  18. Synthesis, characterization and antimicrobial activity of some novel benzimidazole derivatives

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    Immadisetty Sri Krishnanjaneyulu

    2014-01-01

    Full Text Available A series of novel N-((1H-benzoimidazol-1-yl methyl-4-(1-phenyl-5-substituted-4, 5-dihydro-1-benzoimidazol-1-yl methyl-4-(1-phenyl-5-substituted-4, 5-dihydro-1H-pyrazol-3-yl benzenamine were synthesized by treating various 1-(4-((1H-benzoimidazol-1-yl methylamino phenyl-3-substitutedprop-2-en-1-one with phenyl hydrazine in the presence of sodium acetate through a simple ring closure reaction. The starting material, 1-(4-((1H-benzoimidazol-1-yl methylamino phenyl-3-substitutedprop-2-en-1-one,-benzoimidazol-1-yl methylamino phenyl-3-substitutedprop-2-en-1-one, was synthesized from o-phenylenediamine by a multistep synthesis. All the synthesized compounds were characterized by spectroscopic means and elemental analyses. The title compounds were investigated for in vitro antibacterial and antifungal properties against some human pathogenic microorganisms by employing the agar streak dilution method using Ciprofloxacin and Ketoconazole as standard drugs. All title compounds showed activity against the entire strains of microorganism. Structural activity relationship studies reveal that compounds possessing an electron-withdrawing group display better activity than the compounds containing electron-donating groups, whereas the unsubstituted derivatives display moderate activity. Based on the results obtained, N-((1H-benzoimidazol-1-yl methyl-4-(1-phenyl-5-(4-(trifluoromethyl phenyl-4,5-dihydro-1H-pyrazol-3-yl benzenamine 5i was found to be very active compared with the rest of the compounds and standard drugs that were subjected to antimicrobial assay.

  19. Anti-biofilm properties of the antimicrobial peptide temporin 1Tb and its ability, in combination with EDTA, to eradicate Staphylococcus epidermidis biofilms on silicone catheters.

    Science.gov (United States)

    Maisetta, Giuseppantonio; Grassi, Lucia; Di Luca, Mariagrazia; Bombardelli, Silvia; Medici, Chiara; Brancatisano, Franca Lisa; Esin, Semih; Batoni, Giovanna

    2016-08-01

    In search of new antimicrobials with anti-biofilm potential, in the present study activity of the frog-skin derived antimicrobial peptide temporin 1Tb (TB) against Staphylococcus epidermidis biofilms was investigated. A striking ability of TB to kill both forming and mature S. epidermidis biofilms was observed, especially when the peptide was combined with cysteine or EDTA, respectively. Kinetics studies demonstrated that the combination TB/EDTA was active against mature biofilms already after 2-4-h exposure. A double 4-h exposure of biofilms to TB/EDTA further increased the therapeutic potential of the same combination. Of note, TB/EDTA was able to eradicate S. epidermidis biofilms formed in vitro on silicone catheters. At eradicating concentrations, TB/EDTA did not cause hemolysis of human erythrocytes. The results shed light on the anti-biofilm properties of TB and suggest a possible application of the peptide in the lock therapy of catheters infected with S. epidermidis. PMID:27351824

  20. Design of an α-helical antimicrobial peptide with improved cell-selective and potent anti-biofilm activity.

    Science.gov (United States)

    Zhang, Shi-Kun; Song, Jin-Wen; Gong, Feng; Li, Su-Bo; Chang, Hong-Yu; Xie, Hui-Min; Gao, Hong-Wei; Tan, Ying-Xia; Ji, Shou-Ping

    2016-01-01

    AR-23 is a melittin-related peptide with 23 residues. Like melittin, its high α-helical amphipathic structure results in strong bactericidal activity and cytotoxicity. In this study, a series of AR-23 analogues with low amphipathicity were designed by substitution of Ala1, Ala8 and Ile17 with positively charged residues (Arg or Lys) to study the effect of positively charged residue distribution on the biological viability of the antimicrobial peptide. Substitution of Ile17 on the nonpolar face with positively charged Lys dramatically altered the hydrophobicity, amphipathicity, helicity and the membrane-penetrating activity against human cells as well as the haemolytic activity of the peptide. However, substitution on the polar face only slightly affected the peptide biophysical properties and biological activity. The results indicate that the position rather than the number of positively charged residue affects the biophysical properties and selectivity of the peptide. Of all the analogues, A(A1R, A8R, I17K), a peptide with Ala1-Arg, Ala8-Arg and Ile17-Lys substitutions, exhibited similar bactericidal activity and anti-biofilm activity to AR-23 but had much lower haemolytic activity and cytotoxicity against mammalian cells compared with AR-23. Therefore, the findings reported here provide a rationalization for peptide design and optimization, which will be useful for the future development of antimicrobial agents. PMID:27271216

  1. Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

    Science.gov (United States)

    Wirth, Marius; Niro, Giuliana; Leyerer, Kristin

    2016-01-01

    Summary Muraymycins are a promising class of antimicrobial natural products. These uridine-derived nucleoside-peptide antibiotics inhibit the bacterial membrane protein translocase I (MraY), a key enzyme in the intracellular part of peptidoglycan biosynthesis. This review describes the structures of naturally occurring muraymycins, their mode of action, synthetic access to muraymycins and their analogues, some structure–activity relationship (SAR) studies and first insights into muraymycin biosynthesis. It therefore provides an overview on the current state of research, as well as an outlook on possible future developments in this field. PMID:27340469

  2. A New Peptide Isolated from a Marine Derived Streptomyces bacillaris

    OpenAIRE

    Hu, Youcai; MacMillan, John B

    2012-01-01

    A new peptide, l-O-Lac-l-Val-d-O-Hiv-d-Val (1), consisting of d-valine, l-valine, l-lactic acid, and 3-d-hydroxyisovaleric acid, was isolated from the culture of the marine sediment derived Streptomyces bacillaris. The planar structure of compound 1 was assigned by 1D, 2D NMR and mass spectroscopic analyses. Following acid and base hydrolysis, the absolute configuration of the valine residues in 1 were determined by application of the advanced Marfey’s method and the absolute configurations o...

  3. Secapin, a bee venom peptide, exhibits anti-fibrinolytic, anti-elastolytic, and anti-microbial activities.

    Science.gov (United States)

    Lee, Kwang Sik; Kim, Bo Yeon; Yoon, Hyung Joo; Choi, Yong Soo; Jin, Byung Rae

    2016-10-01

    Bee venom contains a variety of peptide constituents that have various biological, toxicological, and pharmacological actions. However, the biological actions of secapin, a venom peptide in bee venom, remain largely unknown. Here, we provide the evidence that Asiatic honeybee (Apis cerana) secapin (AcSecapin-1) exhibits anti-fibrinolytic, anti-elastolytic, and anti-microbial activities. The recombinant mature AcSecapin-1 peptide was expressed in baculovirus-infected insect cells. AcSecapin-1 functions as a serine protease inhibitor-like peptide that has inhibitory effects against plasmin, elastases, microbial serine proteases, trypsin, and chymotrypsin. Consistent with these functions, AcSecapin-1 inhibited the plasmin-mediated degradation of fibrin to fibrin degradation products, thus indicating the role of AcSecapin-1 as an anti-fibrinolytic agent. AcSecapin-1 also inhibited both human neutrophil and porcine pancreatic elastases. Furthermore, AcSecapin-1 bound to bacterial and fungal surfaces and exhibited anti-microbial activity against fungi and gram-positive and gram-negative bacteria. Taken together, our data demonstrated that the bee venom peptide secapin has multifunctional roles as an anti-fibrinolytic agent during fibrinolysis and an anti-microbial agent in the innate immune response. PMID:27208884

  4. Characterization of an abaecin-like antimicrobial peptide identified from a Pteromalus puparum cDNA clone.

    Science.gov (United States)

    Shen, Xiaojing; Ye, Gongyin; Cheng, Xiongying; Yu, Chunyan; Altosaar, Illimar; Hu, Cui

    2010-09-01

    Abaecin is a major antimicrobial peptide, initially identified from the honeybee. In our effort to discover new antimicrobial peptides from the endoparasitoid wasp Pteromalus puparum, we identified an antibacterial cDNA clone that codes a fragment with high amino acid sequence similarity to abaecin. The proline-rich peptide (YVPPVQKPHPNGPKFPTFP, named PP30) was chemically synthesized and characterized in this study. Antimicrobial assays indicated that the cationic peptide was active against both Gram-negative and positive bacteria, but not active against fungi tested. No hemolytic activity was observed against human erythrocytes after 1h incubation at concentration of 125 microM or below. The antibacterial activity of PP30 against Escherichia coli was attenuated in the presence of increasing concentrations of NaCl. Transmission electron microscopic (TEM) examination of PP30-treated E. coli cells showed morphological changes in the cells and extensive damage to the cell membranes. The circular dichroism (CD) spectroscopy studies indicated that PP30 formed random coil structures in phosphate buffer (pH 7.4), 50% TFE and 25 mM SDS solution. Expression analysis of the gene coding for the peptide indicated that its expression was upregulated upon bacterial infection, indicating that the gene may play a role in preventing potential infection by microorganisms during parasitization in Pieris rapae. PMID:20466006

  5. Mammalian antimicrobial proteins and peptides: overview on the RNase A superfamily members involved in innate host defence.

    Science.gov (United States)

    Boix, Ester; Nogués, M Victòria

    2007-05-01

    The review starts with a general outlook of the main mechanisms of action of antimicrobial proteins and peptides, with the final aim of understanding the biological function of antimicrobial RNases, and identifying the key events that account for their selective properties. Although most antibacterial proteins and peptides do display a wide-range spectrum of action, with a cytotoxic activity against bacteria, fungi, eukaryotic parasites and viruses, we have only focused on their bactericidal activity. We start with a detailed description of the main distinctive structural features of the bacteria target and on the polypeptides, which act as selective host defence weapons.Following, we include an overview of all the current available information on the mammalian RNases which display an antimicrobial activity. There is a wealth of information on the structural, catalytic mechanism and evolutionary relationships of the RNase A superfamily. The bovine pancreatic RNase A (RNase A), the reference member of the mammalian RNase family, has been the main research object of several Nobel laureates in the 60s, 70s and 80s. A potential antimicrobial function was only recently suggested for several members of this family. In fact, the recent evolutionary studies indicate that this protein family may have started off with a host defence function. Antimicrobial RNases constitute an interesting example of proteins involved in the mammalian innate immune defence system. Besides, there is wealth of available information on the mechanism of action of short antimicrobial peptides, but little is known on larger polypeptides, that is, on proteins. Therefore, the identification of the mechanisms of action of antimicrobial RNases would contribute to the understanding of the proteins involved in the innate immunity.

  6. Stearylated antimicrobial peptide [D]-K6L9 with cell penetrating property for efficient gene transfer.

    Science.gov (United States)

    Zhang, Wei; Song, Jingjing; Liang, Ranran; Zheng, Xin; Chen, Jianbo; Li, Guolin; Zhang, Bangzhi; Wang, Kairong; Yan, Xiang; Wang, Rui

    2013-08-01

    Stearyl-cell penetrating peptides (CPPs) have been proved to be efficient nonviral gene vectors. Due to the similarities between antimicrobial peptides and CPPs, we constructed a novel type of gene vectors by introducing stearyl moiety to the N-terminus of antimicrobial peptide [D]-K6L9. In this study, stearyl-[D]-K6L9 delivered plasmids into cells by clathrin- and caveolin-mediated endocytosis. Gratifyingly, stearyl-[D]-K6L9 exhibited high transfection efficiency and almost reached the level of Lipofectamine 2000. Taken together, the combination of the stearyl moiety with [D]-K6L9 provides a novel framework for the development of excellent nonviral gene vectors. PMID:23727033

  7. Application of MALDI-MSI for detection of antimicrobial peptides in tissues of the marine invertebrate Arenicola marina

    Directory of Open Access Journals (Sweden)

    AL Maltseva

    2016-07-01

    Full Text Available Application of MALDI-MSI for detection of antimicrobial peptides in tissues of the marine invertebrate Arenicola marina AL Maltseva1 , VV Starunov1 , PA Zykin2 1 Department of Invertebrate Zoology, St Petersburg State University, St Petersburg, Russia 2 Department of Cytology and Histology, St Petersburg State University, St Petersburg, Russia Accepted June 13, 2016 Abstract MALDI imaging mass-spectrometry (MALDI-MSI is a highly informative approach combining morphology with molecular data. It is widely applied in neuroscience, plant science, cancer-biology, biomedicine, including clinical, and preclinical studies, but not for investigation of endogenous peptides/proteins or metabolites in marine invertebrates. We examined the informativeness of MALDIMSI for analysis of distribution of antimicrobial peptides (arenicins in the polychete Arenicola marina and concluded that it can be successfully used as a primary rough express screening method.

  8. Lights, Camera, Action! Antimicrobial Peptide Mechanisms Imaged in Space and Time.

    Science.gov (United States)

    Choi, Heejun; Rangarajan, Nambirajan; Weisshaar, James C

    2016-02-01

    Deeper understanding of the bacteriostatic and bactericidal mechanisms of antimicrobial peptides (AMPs) should help in the design of new antibacterial agents. Over several decades, a variety of biochemical assays have been applied to bulk bacterial cultures. While some of these bulk assays provide time resolution of the order of 1min, they do not capture faster mechanistic events. Nor can they provide subcellular spatial information or discern cell-to-cell heterogeneity within the bacterial population. Single-cell, time-resolved imaging assays bring a completely new spatiotemporal dimension to AMP mechanistic studies. We review recent work that provides new insights into the timing, sequence, and spatial distribution of AMP-induced effects on bacterial cells.

  9. Comparing selection on S. aureus between antimicrobial peptides and common antibiotics.

    Science.gov (United States)

    Dobson, Adam J; Purves, Joanne; Kamysz, Wojciech; Rolff, Jens

    2013-01-01

    With a diminishing number of effective antibiotics, there has been interest in developing antimicrobial peptides (AMPs) as drugs. However, any new drug faces potential bacterial resistance evolution. Here, we experimentally compare resistance evolution in Staphylococcus aureus selected by three AMPs (from mammals, amphibians and insects), a combination of two AMPs, and two antibiotics: the powerful last-resort vancomycin and the classic streptomycin. We find that resistance evolves readily against single AMPs and against streptomycin, with no detectable fitness cost. However the response to selection from our combination of AMPs led to extinction, in a fashion qualitatively similar to vancomycin. This is consistent with the hypothesis that simultaneous release of multiple AMPs during immune responses is a factor which constrains evolution of AMP resistant pathogens.

  10. Comparing selection on S. aureus between antimicrobial peptides and common antibiotics.

    Directory of Open Access Journals (Sweden)

    Adam J Dobson

    Full Text Available With a diminishing number of effective antibiotics, there has been interest in developing antimicrobial peptides (AMPs as drugs. However, any new drug faces potential bacterial resistance evolution. Here, we experimentally compare resistance evolution in Staphylococcus aureus selected by three AMPs (from mammals, amphibians and insects, a combination of two AMPs, and two antibiotics: the powerful last-resort vancomycin and the classic streptomycin. We find that resistance evolves readily against single AMPs and against streptomycin, with no detectable fitness cost. However the response to selection from our combination of AMPs led to extinction, in a fashion qualitatively similar to vancomycin. This is consistent with the hypothesis that simultaneous release of multiple AMPs during immune responses is a factor which constrains evolution of AMP resistant pathogens.

  11. Synthesis and biological evaluation of some new amide moiety bearing quinoxaline derivatives as antimicrobial agents.

    Science.gov (United States)

    Abu Mohsen, U; Yurttaş, L; Acar, U; Özkay, Y; Kaplacikli, Z A; Karaca Gencer, H; Cantürk, Z

    2015-05-01

    In this study, we aimed to synthesize some new quinoxaline derivatives bearing amide moiety and to evaluate their antimicrobial activity. A set of 16 novel compounds of N-[2,3-bis(4-methoxy/methylphenyl)quinoxalin-6-yl]-substituted benzamide derivatives were synthesized by reacting 2,3-bis(4-methoxyphenyl)-6-aminoquinoxaline or 2,3-bis(4-methylphenyl)-6-aminoquinoxaline with benzoyl chloride derivatives in tetrahydrofuran and investigated for their antimicrobial activity. The structures of the obtained final compounds were confirmed by spectral data (IR, (1)H-NMR, (13)C-NMR and MS). The antimicrobial activity of the compounds were determined by using the microbroth dilution method. Antimicrobial activity results revealed that synthesized compounds exhibited remarkable activity against Candida krusei (ATCC 6258) and Candida parapsilosis (ATCC 22019).

  12. Natural and synthetic cathelicidin peptides with anti-microbial and anti-biofilm activity against Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    van Hoek Monique L

    2011-05-01

    Full Text Available Abstract Background Chronic, infected wounds typically contain multiple genera of bacteria, including Staphylococcus aureus, many of which are strong biofilm formers. Bacterial biofilms are thought to be a direct impediment to wound healing. New therapies that focus on a biofilm approach may improve the recovery and healing rate for infected wounds. In this study, cathelicidins and related short, synthetic peptides were tested for their anti-microbial effectiveness as well as their ability to inhibit the ability of S. aureus to form biofilms. Results The helical human cathelicidin LL-37 was tested against S. aureus, and was found to exhibit effective anti-microbial, anti-attachment as well as anti-biofilm activity at concentrations in the low μg/ml range. The effect of peptide chirality and associated protease-resistance was explored through the use of an all-D amino acid peptide, D-LL-37, and in turn compared to scrambled LL-37. Helical cathelicidins have been identified in other animals such as the Chinese cobra, Naja atra (NA-CATH. We previously identified an 11-residue imperfectly repeated pattern (ATRA motif within the sequence of NA-CATH. A series of short peptides (ATRA-1, -2, -1A, as well as a synthetic peptide, NA-CATH:ATRA1-ATRA1, were designed to explore the significance of the conserved residues within the ATRA motif for anti-microbial activity. The CD spectrum of NA-CATH and NA-CATH:ATRA1-ATRA1 revealed the structural properties of these peptides and suggested that helicity may factor into their anti-microbial and anti-biofilm activities. Conclusions The NA-CATH:ATRA1-ATRA1 peptide inhibits the production of biofilm by S. aureus in the presence of salt, exhibiting anti-biofilm activity at lower peptide concentrations than NA-CATH, LL-37 and D-LL-37; and demonstrates low cytoxicity against host cells but does not affect bacterial attachment. The peptides utilized in this anti-biofilm approach may provide templates for a new group of

  13. A novel immune evasion strategy of candida albicans: proteolytic cleavage of a salivary antimicrobial peptide.

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    Timothy F Meiller

    Full Text Available Oropharyngeal candidiasis is an opportunistic infection considered to be a harbinger of AIDS. The etiologic agent Candida albicans is a fungal species commonly colonizing human mucosal surfaces. However, under conditions of immune dysfunction, colonizing C. albicans can become an opportunistic pathogen causing superficial or even life-threatening infections. The reasons behind this transition, however, are not clear. In the oral cavity, salivary antimicrobial peptides are considered to be an important part of the host innate defense system in the prevention of microbial colonization. Histatin-5 specifically has exhibited potent activity against C. albicans. Our previous studies have shown histatin-5 levels to be significantly reduced in the saliva of HIV+ individuals, indicating an important role for histatin-5 in keeping C. albicans in its commensal stage. The versatility in the pathogenic potential of C. albicans is the result of its ability to adapt through the regulation of virulence determinants, most notably of which are proteolytic enzymes (Saps, involved in tissue degradation. In this study, we show that C. albicans cells efficiently and rapidly degrade histatin-5, resulting in loss of its anti-candidal potency. In addition, we demonstrate that this cellular activity is due to proteolysis by a member of the secreted aspartic proteases (Sap family involved in C. albicans pathogenesis. Specifically, the proteolysis was attributed to Sap9, in turn identifying histatin-5 as the first host-specific substrate for that isoenzyme. These findings demonstrate for the first time the ability of a specific C. albicans enzyme to degrade and deactivate a host antimicrobial peptide involved in the protection of the oral mucosa against C. albicans, thereby providing new insights into the factors directing the transition of C. albicans from commensal to pathogen, with important clinical implications for alternative therapy. This report characterizes the

  14. IL-4 and IL-13 exposure during mucociliary differentiation of bronchial epithelial cells increases antimicrobial activity and expression of antimicrobial peptides

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    Prins Frans A

    2011-05-01

    Full Text Available Abstract The airway epithelium forms a barrier against infection but also produces antimicrobial peptides (AMPs and other inflammatory mediators to activate the immune system. It has been shown that in allergic disorders, Th2 cytokines may hamper the antimicrobial activity of the epithelium. However, the presence of Th2 cytokines also affects the composition of the epithelial layer which may alter its function. Therefore, we investigated whether exposure of human primary bronchial epithelial cells (PBEC to Th2 cytokines during mucociliary differentiation affects expression of the human cathelicidin antimicrobial protein (hCAP18/LL-37 and human beta defensins (hBD, and antimicrobial activity. PBEC were cultured at an air-liquid interface (ALI for two weeks in the presence of various concentrations of IL-4 or IL-13. Changes in differentiation and in expression of various AMPs and the antimicrobial proteinase inhibitors secretory leukocyte protease inhibitor (SLPI and elafin were investigated as well as antimicrobial activity. IL-4 and IL-13 increased mRNA expression of hCAP18/LL-37 and hBD-2. Dot blot analysis also showed an increase in hCAP18/LL-37 protein in apical washes of IL-4-treated ALI cultures, whereas Western Blot analysis showed expression of a protein of approximately 4.5 kDa in basal medium of IL-4-treated cultures. Using sandwich ELISA we found that also hBD-2 in apical washes was increased by both IL-4 and IL-13. SLPI and elafin levels were not affected by IL-4 or IL-13 at the mRNA or protein level. Apical wash obtained from IL-4- and IL-13-treated cultures displayed increased antimicrobial activity against Pseudomonas aeruginosa compared to medium-treated cultures. In addition, differentiation in the presence of Th2 cytokines resulted in increased MUC5AC production as has been shown previously. These data suggest that prolonged exposure to Th2 cytokines during mucociliary differentiation contributes to antimicrobial defence by

  15. Use of Natural Antimicrobial Peptides and Bacterial Biopolymers for Cultured Pearl Production.

    Science.gov (United States)

    Simon-Colin, Christelle; Gueguen, Yannick; Bachere, Evelyne; Kouzayha, Achraf; Saulnier, Denis; Gayet, Nicolas; Guezennec, Jean

    2015-06-01

    Cultured pearls are the product of grafting and rearing of Pinctada margaritifera pearl oysters in their natural environment. Nucleus rejections and oyster mortality appear to result from bacterial infections or from an inappropriate grafting practice. To reduce the impact of bacterial infections, synthetic antibiotics have been applied during the grafting practice. However, the use of such antibiotics presents a number of problems associated with their incomplete biodegradability, limited efficacy in some cases, and an increased risk of selecting for antimicrobial resistant bacteria. We investigated the application of a marine antimicrobial peptide, tachyplesin, which is present in the Japanese horseshoe crab Tachypleus tridentatus, in combination with two marine bacterial exopolymers as alternative treatment agents. In field studies, the combination treatment resulted in a significant reduction in graft failures vs. untreated controls. The combination of tachyplesin (73 mg/L) with two bacterial exopolysaccharides (0.5% w/w) acting as filming agents, reduces graft-associated bacterial contamination. The survival data were similar to that reported for antibiotic treatments. These data suggest that non-antibiotic treatments of pearl oysters may provide an effective means of improving oyster survival following grafting procedures.

  16. Modulation of antimicrobial host defense peptide gene expression by free fatty acids.

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    Lakshmi T Sunkara

    Full Text Available Routine use of antibiotics at subtherapeutic levels in animal feed drives the emergence of antimicrobial resistance. Development of antibiotic-alternative approaches to disease control and prevention for food animals is imperatively needed. Previously, we showed that butyrate, a major species of short-chain fatty acids (SCFAs fermented from undigested fiber by intestinal microflora, is a potent inducer of endogenous antimicrobial host defense peptide (HDP genes in the chicken (PLoS One 2011, 6: e27225. In the present study, we further revealed that, in chicken HD11 macrophages and primary monocytes, induction of HDPs is largely in an inverse correlation with the aliphatic hydrocarbon chain length of free fatty acids, with SCFAs being the most potent, medium-chain fatty acids moderate and long-chain fatty acids marginal. Additionally, three SCFAs, namely acetate, propionate, and butyrate, exerted a strong synergy in augmenting HDP gene expression in chicken cells. Consistently, supplementation of chickens with a combination of three SCFAs in water resulted in a further reduction of Salmonella enteritidis in the cecum as compared to feeding of individual SCFAs. More importantly, free fatty acids enhanced HDP gene expression without triggering proinflammatory interleukin-1β production. Taken together, oral supplementation of SCFAs is capable of boosting host immunity and disease resistance, with potential for infectious disease control and prevention in animal agriculture without relying on antibiotics.

  17. Use of Natural Antimicrobial Peptides and Bacterial Biopolymers for Cultured Pearl Production

    Science.gov (United States)

    Simon-Colin, Christelle; Gueguen, Yannick; Bachere, Evelyne; Kouzayha, Achraf; Saulnier, Denis; Gayet, Nicolas; Guezennec, Jean

    2015-01-01

    Cultured pearls are the product of grafting and rearing of Pinctada margaritifera pearl oysters in their natural environment. Nucleus rejections and oyster mortality appear to result from bacterial infections or from an inappropriate grafting practice. To reduce the impact of bacterial infections, synthetic antibiotics have been applied during the grafting practice. However, the use of such antibiotics presents a number of problems associated with their incomplete biodegradability, limited efficacy in some cases, and an increased risk of selecting for antimicrobial resistant bacteria. We investigated the application of a marine antimicrobial peptide, tachyplesin, which is present in the Japanese horseshoe crab Tachypleus tridentatus, in combination with two marine bacterial exopolymers as alternative treatment agents. In field studies, the combination treatment resulted in a significant reduction in graft failures vs. untreated controls. The combination of tachyplesin (73 mg/L) with two bacterial exopolysaccharides (0.5% w/w) acting as filming agents, reduces graft-associated bacterial contamination. The survival data were similar to that reported for antibiotic treatments. These data suggest that non-antibiotic treatments of pearl oysters may provide an effective means of improving oyster survival following grafting procedures. PMID:26110895

  18. Use of Natural Antimicrobial Peptides and Bacterial Biopolymers for Cultured Pearl Production

    Directory of Open Access Journals (Sweden)

    Christelle Simon-Colin

    2015-06-01

    Full Text Available Cultured pearls are the product of grafting and rearing of Pinctada margaritifera pearl oysters in their natural environment. Nucleus rejections and oyster mortality appear to result from bacterial infections or from an inappropriate grafting practice. To reduce the impact of bacterial infections, synthetic antibiotics have been applied during the grafting practice. However, the use of such antibiotics presents a number of problems associated with their incomplete biodegradability, limited efficacy in some cases, and an increased risk of selecting for antimicrobial resistant bacteria. We investigated the application of a marine antimicrobial peptide, tachyplesin, which is present in the Japanese horseshoe crab Tachypleus tridentatus, in combination with two marine bacterial exopolymers as alternative treatment agents. In field studies, the combination treatment resulted in a significant reduction in graft failures vs. untreated controls. The combination of tachyplesin (73 mg/L with two bacterial exopolysaccharides (0.5% w/w acting as filming agents, reduces graft-associated bacterial contamination. The survival data were similar to that reported for antibiotic treatments. These data suggest that non-antibiotic treatments of pearl oysters may provide an effective means of improving oyster survival following grafting procedures.

  19. Mucosal gene expression of antimicrobial peptides in inflammatory bowel disease before and after first infliximab treatment.

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    Ingrid Arijs

    Full Text Available BACKGROUND: Antimicrobial peptides (AMPs protect the host intestinal mucosa against microorganisms. Abnormal expression of defensins was shown in inflammatory bowel disease (IBD, but it is not clear whether this is a primary defect. We investigated the impact of anti-inflammatory therapy with infliximab on the mucosal gene expression of AMPs in IBD. METHODOLOGY/PRINCIPAL FINDINGS: Mucosal gene expression of 81 AMPs was assessed in 61 IBD patients before and 4-6 weeks after their first infliximab infusion and in 12 control patients, using Affymetrix arrays. Quantitative real-time reverse-transcription PCR and immunohistochemistry were used to confirm microarray data. The dysregulation of many AMPs in colonic IBD in comparison with control colons was widely restored by infliximab therapy, and only DEFB1 expression remained significantly decreased after therapy in the colonic mucosa of IBD responders to infliximab. In ileal Crohn's disease (CD, expression of two neuropeptides with antimicrobial activity, PYY and CHGB, was significantly decreased before therapy compared to control ileums, and ileal PYY expression remained significantly decreased after therapy in CD responders. Expression of the downregulated AMPs before and after treatment (DEFB1 and PYY correlated with villin 1 expression, a gut epithelial cell marker, indicating that the decrease is a consequence of epithelial damage. CONCLUSIONS/SIGNIFICANCE: Our study shows that the dysregulation of AMPs in IBD mucosa is the consequence of inflammation, but may be responsible for perpetuation of inflammation due to ineffective clearance of microorganisms.

  20. The antimicrobial peptide sublancin ameliorates necrotic enteritis induced by Clostridium perfringens in broilers.

    Science.gov (United States)

    Wang, S; Zeng, X F; Wang, Q W; Zhu, J L; Peng, Q; Hou, C L; Thacker, P; Qiao, S Y

    2015-10-01

    Sublancin is an antimicrobial peptide produced by 168 containing 37 amino acids. The objective of this study was to investigate its inhibitory efficacy against both in vitro and in vivo. In the in vitro study, we determined that sublancin had a minimum inhibitory concentration of 8 μM against , which was much higher than the antibiotic lincomycin (0.281 μM). Scanning electron microscopy showed that sublancin damaged the morphology of . The in vivo study was conducted on broilers for a 28-d period using a completely randomized design. A total of 252 chickens at 1 d of age were randomly assigned to 1 of 6 treatments including an uninfected control; an infected control; 3 infected groups supplemented with sublancin at 2.88, 5.76, or 11.52 mg activity/L of water; and an infected group supplemented with lincomycin at 75 mg activity/L of water (positive control). Necrotic enteritis was induced in the broilers by oral inoculation of on d 15 through 21. Thereafter, the sublancin or lincomycin were administered fresh daily for a period of 7 days. The challenge resulted in a significant decrease in ADG ( enteritis induced by in vivo than lincomycin. These novel findings indicate that sublancin could be used as a potential antimicrobial agent to control necrotic enteritis.

  1. Expression of Caenorhabditis elegans antimicrobial peptide NLP-31 in Escherichia coli

    Science.gov (United States)

    Lim, Mei-Perng; Nathan, Sheila

    2014-09-01

    Burkholderia pseudomallei is the causative agent of melioidosis, a fulminant disease endemic in Southeast Asia and Northern Australia. The standardized form of therapy is antibiotics treatment; however, the bacterium has become increasingly resistant to these antibiotics. This has spurred the need to search for alternative therapeutic agents. Antimicrobial peptides (AMPs) are small proteins that possess broad-spectrum antimicrobial activity. In a previous study, the nematode Caenorhabditis elegans was infected by B. pseudomallei and a whole animal transcriptome analysis identified a number of AMP-encoded genes which were induced significantly in the infected worms. One of the AMPs identified is NLP-31 and to date, there are no reports of anti-B. pseudomallei activity demonstrated by NLP-31. To produce NLP-31 protein for future studies, the gene encoding for NLP-31 was cloned into the pET32b expression vector and transformed into Escherichia coli BL21(DE3). Protein expression was induced with 1 mM IPTG for 20 hours at 20°C and recombinant NLP-31 was detected in the soluble fraction. Taken together, a simple optimized heterologous production of AMPs in an E. coli expression system has been successfully developed.

  2. Expression profiles of antimicrobial peptides (AMPs) and their regulation by Relish

    Institute of Scientific and Technical Information of China (English)

    WANG Dongdong; LI Fuhua; LI Shihao; WEN Rong; XIANG Jianhai

    2012-01-01

    Antimicrobial peptides (AMPs),as key immune effectors,play important roles in the innate immune system of invertebrates.Different types of AMPs,including Penaeidin,Crustin,ALF (antilipopolysaccharide factor) have been identified in different penaeid shrimp; however,systematic analyses on the function of different AMPs in shrimp responsive to different types of bacteria are very limited.In this study,we analyzed the expression profiles of AMPs in the Chinese shrimps,Fenneropenaeus chinensis,simultaneously by real-time RT-PCR (reverse transcription-polymerase chain reaction) when shrimp were challenged with Micrococcus lysodeikticus (Gram-positive,G+) or Vibrio anguillarium (Gram-negative,G).Different AMPs showed different expression profiles when shrimp were injected with one type of bacterium,and one AMP also showed different expression profiles when shrimp were challenged with different bacteria.Furthermore,the expression of these AMPs showed temporal expression profiles,suggesting that different AMPs function coordinately in bacteria-infected shrimp.An RNA interference approach was used to study the function of the Relish transcription factor in regulating the transcription of different AM Ps.The current study showed that Relish could regulate the transcription of different AMPs in shrimp.Differential expression profiles of AMPs in shrimp injected with different types of bacteria indicated that a complicated antimicrobial response network existed in shrimp.These data contribute to our understanding of immunity in shrimp and may provide a strategy for the control of disease in shrimp.

  3. Antimicrobial proteins and peptides in early life: ontogeny and translational opportunities

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    Anna Jane Battersby

    2016-08-01

    Full Text Available Whilst developing adaptive immune responses, young infants are especially vulnerable to serious infections including sepsis, meningitis and pneumonia. Antimicrobial proteins and peptides (APPs are key effectors that function as broad-spectrum anti-infectives. This review seeks to summarise the clinically relevant functional qualities of APPs and the increasing clinical trial evidence for their use to combat serious infections in infancy. Levels of APPs are relatively low in early life, especially in infants born preterm or with low birth weight (LBW. There are several rationales for the potential clinical utility of APPs in the prevention and treatment of infections in infants: (a APPs may be most helpful in those with reduced levels; (b during sepsis microbial products signal via pattern recognition receptors (PRRs causing potentially harmful inflammation which APPs may counteract; and (c in the era of antibiotic resistance, development of new anti-infective strategies is essential. Evidence supports the potential clinical utility of exogenous APPs to reduce infection-related morbidity in infancy. Further studies should characterize the ontogeny of antimicrobial activity in mucosal and systemic compartments, and examine the efficacy of exogenous-APP formulations to inform translational development of APPs for infant groups.

  4. Expression profiles of antimicrobial peptides (AMPs) and their regulation by Relish

    Science.gov (United States)

    Wang, Dongdong; Li, Fuhua; Li, Shihao; Wen, Rong; Xiang, Jianhai

    2012-07-01

    Antimicrobial peptides (AMPs), as key immune effectors, play important roles in the innate immune system of invertebrates. Different types of AMPs, including Penaeidin, Crustin, ALF (antilipopolysaccharide factor) have been identified in different penaeid shrimp; however, systematic analyses on the function of different AMPs in shrimp responsive to different types of bacteria are very limited. In this study, we analyzed the expression profiles of AMPs in the Chinese shrimps, Fenneropenaeus chinensis, simultaneously by real-time RT-PCR (reverse transcription-polymerase chain reaction) when shrimp were challenged with Micrococcus lysodeikticus (Gram-positive, G+) or Vibrio anguillarium (Gram-negative, G-). Different AMPs showed different expression profiles when shrimp were injected with one type of bacterium, and one AMP also showed different expression profiles when shrimp were challenged with different bacteria. Furthermore, the expression of these AMPs showed temporal expression profiles, suggesting that different AMPs function coordinately in bacteria-infected shrimp. An RNA interference approach was used to study the function of the Relish transcription factor in regulating the transcription of different AMPs. The current study showed that Relish could regulate the transcription of different AMPs in shrimp. Differential expression profiles of AMPs in shrimp injected with different types of bacteria indicated that a complicated antimicrobial response network existed in shrimp. These data contribute to our understanding of immunity in shrimp and may provide a strategy for the control of disease in shrimp.

  5. The influence of selected antimicrobial peptides on the physiology of the immune system

    Science.gov (United States)

    Golab, Karolina; Mittag, Anja; Pierzchalski, Arkadiusz; Bocsi, Jozsef; Kamysz, Wojciech; Tarnok, Attila

    2011-02-01

    Antimicrobial peptides (AMPs) are an essential part of the innate immune system that serves as a first line of defense against invading pathogens. Recently, immunomodulatory activities of AMPs have begun to be appreciated, implying the usefulness of AMPs in the treatment of infectious disease. The aim of this strategy is the modulation of host immune responses to enhance clearance of infectious agents and reduce tissue damage due to inflammation. Although AMPs could be used as therapeutic agents, a more detailed understanding of how they affect host cells is needed. Hence, several AMPs have been investigated for their potential as a new class of antimicrobial drugs in this study. Synthetic AMPs and AMPs of natural origin were tested on human leukocytes by flow cytometry. Dose- and time-dependent cytotoxic effects could be observed by propidium iodide staining. Different leukocyte subtypes seem to be susceptible to AMP treatment while others were not affected, even in high concentrations. In conclusion, AMPs have an impact on host immune cells. However, their role in stimulation of chemokine production and enhanced leukocyte recruitment remains a crucial aspect and further studies are needed.

  6. Pore formation by antimicrobial peptides: structural tendencies in bulk and quasi-2D membrane systems

    Science.gov (United States)

    Gordon, Vernita; Yang, Lihua; Davis, Matthew; Som, A.; Tew, G.; Wong, Gerard

    2007-03-01

    Antimicrobial peptides are cationic, amphiphilic structures that are key components of innate immunity. A prototypical family of synthetic analogs are the phenylene ethynylene antimicrobial oligomers (AMOs), which have hydrophobic alkyl chains connected to cationic hydrophilic regions. Synchrotron small-angle x-ray scattering (SAXS) shows that when AMO is mixed with concentrated model membranes, initially in the form of Small Unilamellar Vesicles, the sample forms the inverted hexagonal phase. This is a 3-dimensional phase characterized by a regular array of size-defined water channels. We demonstrate how this structural tendency is expressed when AMOs interact with dilute model membranes in the form of Giant Unilamellar Vesicles (GUVs). Using confocal microscopy, we see that applying AMO to the GUVs causes small encapsulated molecules to be released while large molecules are retained, indicating that size-defined pores have been created. Examining the partial release of polydisperse intermediately-sized molecules allows a closer measurement of the pore size, and there are indications that this single-vesicle microscopy will allow elucidation of the kinetics of the pore-forming process.

  7. Effect of a novel antimicrobial peptide chrysophsin-1 on oral pathogens and Streptococcus mutans biofilms.

    Science.gov (United States)

    Wang, Wei; Tao, Rui; Tong, Zhongchun; Ding, Yonglin; Kuang, Rong; Zhai, Shafei; Liu, Jun; Ni, Longxing

    2012-02-01

    Dental caries and pulpal diseases are common oral bacterial infectious diseases. Controlling and reducing the causative pathogens, such as Streptococcus mutans and Enterococcus faecalis, is a key step toward prevention and treatment of the two diseases. Chrysophsin-1 is a cationic antimicrobial peptide having broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria. In this study, we investigated the antibacterial activity of chrysophsin-1 against several oral pathogens and S. mutans biofilms and performed a preliminary study of the antimicrobial mechanism. Cytotoxic activity of chrysophsin-1 against human gingival fibroblasts (HGFs) was investigated. Minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and time-kill assay were used to evaluate the killing effect of chrysophsin-1. Scanning electron microscopy (SEM) was used to analyze morphological and membrane change in oral pathogens. Live/Dead staining, in conjunction with confocal scanning laser microscopy (CSLM), was used to observe and analyze S. mutans biofilms. MIC and MBC results demonstrated that chrysophsin-1 had different antimicrobial activities against the tested oral microbes. Lysis and pore formation of the cytomembrane were observed following treatment of the bacteria with chrysophsin-1 for 4h or 24h by SEM. Furthermore, CLSM images showed that chrysophsin-1 remarkably reduced the viability of cells within biofilms and had a significantly lethal effect against S. mutans biofilms. Toxicity studies showed that chrysophsin-1 at concentration between 8 μg/ml and 32 μg/ml had little effect on viability of HGFs in 5 min. Our findings suggest that chrysophsin-1 may have potential clinical applications in the prevention and treatment of dental caries and pulpal diseases.

  8. Synergy between a collagen IV mimetic peptide and a somatotropin-domain derived peptide as angiogenesis and lymphangiogenesis inhibitors

    OpenAIRE

    Koskimaki, Jacob E.; Lee, Esak; Chen, William; Rivera, Corban G.; Rosca, Elena V.; Pandey, Niranjan B.; Popel, Aleksander S.

    2012-01-01

    Angiogenesis is central to many physiological and pathological processes. Here we show two potent bioinformatically-identified peptides, one derived from collagen IV and translationally optimized, and one from a somatotropin domain-containing protein, synergize in angiogenesis and lymphangiogenesis assays including cell adhesion, migration and in vivo Matrigel plugs. Peptide-peptide combination therapies have recently been applied to diseases such as human immunodeficiency virus (HIV), but re...

  9. Distinct behaviour of the homeodomain derived cell penetrating peptide penetratin in interaction with different phospholipids.

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    Ofelia Maniti

    Full Text Available BACKGROUND: Penetratin is a protein transduction domain derived from the homeoprotein Antennapedia. Thereby it is currently used as a cell penetrating peptide to introduce diverse molecules into eukaryotic cells, and it could also be involved in the cellular export of transcription factors. Moreover, it has been shown that it is able to act as an antimicrobial agent. The mechanisms involved in all these processes are quite controversial. METHODOLOGY/PRINCIPAL FINDINGS: In this article, we report spectroscopic, calorimetric and biochemical data on the penetratin interaction with three different phospholipids: phosphatidylcholine (PC and phosphatidylethanolamine (PE to mimic respectively the outer and the inner leaflets of the eukaryotic plasma membrane and phosphatidylglycerol (PG to mimic the bacterial membrane. We demonstrate that with PC, penetratin is able to form vesicle aggregates with no major change in membrane fluidity and presents no well defined secondary structure organization. With PE, penetratin aggregates vesicles, increases membrane rigidity and acquires an α-helical structure. With PG membranes, penetratin does not aggregate vesicles but decreases membrane fluidity and acquires a structure with both α-helical and β-sheet contributions. CONCLUSIONS/SIGNIFICANCE: These data from membrane models suggest that the different penetratin actions in eukaryotic cells (membrane translocation during export and import and on prokaryotes may result from different peptide and lipid structural arrangements. The data suggest that, for eukaryotic cell penetration, penetratin does not acquire classical secondary structure but requires a different conformation compared to that in solution.

  10. A polyalanine peptide derived from polar fish with anti-infectious activities

    Science.gov (United States)

    Cardoso, Marlon H.; Ribeiro, Suzana M.; Nolasco, Diego O.; de La Fuente-Núñez, César; Felício, Mário R.; Gonçalves, Sónia; Matos, Carolina O.; Liao, Luciano M.; Santos, Nuno C.; Hancock, Robert E. W.; Franco, Octávio L.; Migliolo, Ludovico

    2016-02-01

    Due to the growing concern about antibiotic-resistant microbial infections, increasing support has been given to new drug discovery programs. A promising alternative to counter bacterial infections includes the antimicrobial peptides (AMPs), which have emerged as model molecules for rational design strategies. Here we focused on the study of Pa-MAP 1.9, a rationally designed AMP derived from the polar fish Pleuronectes americanus. Pa-MAP 1.9 was active against Gram-negative planktonic bacteria and biofilms, without being cytotoxic to mammalian cells. By using AFM, leakage assays, CD spectroscopy and in silico tools, we found that Pa-MAP 1.9 may be acting both on intracellular targets and on the bacterial surface, also being more efficient at interacting with anionic LUVs mimicking Gram-negative bacterial surface, where this peptide adopts α-helical conformations, than cholesterol-enriched LUVs mimicking mammalian cells. Thus, as bacteria present varied physiological features that favor antibiotic-resistance, Pa-MAP 1.9 could be a promising candidate in the development of tools against infections caused by pathogenic bacteria.

  11. Quantitative structure-activity relationships of antimicrobial fatty acids and derivatives against Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Hui ZHANG; Lu ZHANG; Li-juan PENG; Xiao-wu DONG; Di WU; Vivian Chi-Hua WU; Feng-qin FENG

    2012-01-01

    Fatty acids and derivatives (FADs) are resources for natural antimicrobials.In order to screen for additional potent antimicrobial agents,the antimicrobial activities of FADs against Staphylococcus aureus were examined using a microplate assay.Monoglycerides of fatty acids were the most potent class of fatty acids,among which monotridecanoin possessed the most potent antimicrobial activity.The conventional quantitative structure-activity relationship (QSAR) and comparative molecular field analysis (CoMFA) were performed to establish two statistically reliable models (conventional QSAR:R2=0.942,Q2LOO=0.910; CoMFA:R2=0.979,Q2=0.588,respectively).Improved forecasting can be achieved by the combination of these two models that provide a good insight into the structureactivity relationships of the FADs and that may be useful to design new FADs as antimicrobial agents.

  12. Two Novel Dermaseptin-Like Antimicrobial Peptides with Anticancer Activities from the Skin Secretion of Pachymedusa dacnicolor.

    Science.gov (United States)

    Shi, Daning; Hou, Xiaojuan; Wang, Lei; Gao, Yitian; Wu, Di; Xi, Xinping; Zhou, Mei; Kwok, Hang Fai; Duan, Jinao; Chen, Tianbao; Shaw, Chris

    2016-01-01

    The dermaseptin antimicrobial peptide family contains members of 27-34 amino acids in length that have been predominantly isolated from the skins/skin secretions of phyllomedusine leaf frogs. By use of a degenerate primer in Rapid amplification of cDNA ends (RACE) PCR designed to a common conserved domain within the 5'-untranslated regions of previously-characterized dermaseptin encoding cDNAs, two novel members of this peptide family, named dermaseptin-PD-1 and dermaseptin-PD-2, were identified in the skin secretion of the phyllomedusine frog, Pachymedusa dacnicolor. The primary structures of both peptides were predicted from cloned cDNAs, as well as being confirmed by mass spectral analysis of crude skin secretion fractions resulted from reversed-phase high-performance liquid chromatography. Chemically-synthesized replicates of dermaseptin-PD-1 and dermaseptin-PD-2 were investigated for antimicrobial activity using standard model microorganisms (Gram-positive bacteria, Gram-negative bacteria and a yeast) and for cytotoxicity using mammalian red blood cells. The possibility of synergistic effects between the two peptides and their anti-cancer cell proliferation activities were assessed. The peptides exhibited moderate to high inhibition against the growth of the tested microorganisms and cancer cell lines with low haemolytic activity. Synergistic interaction between the two peptides in inhibiting the proliferation of Escherichia coli and human neuronal glioblastoma cell line, U251MG was also manifested. PMID:27187467

  13. Two interdependent mechanisms of antimicrobial activity allow for efficient killing in nylon-3-based polymeric mimics of innate immunity peptides.

    Science.gov (United States)

    Lee, Michelle W; Chakraborty, Saswata; Schmidt, Nathan W; Murgai, Rajan; Gellman, Samuel H; Wong, Gerard C L

    2014-09-01

    Novel synthetic mimics of antimicrobial peptides have been developed to exhibit structural properties and antimicrobial activity similar to those of natural antimicrobial peptides (AMPs) of the innate immune system. These molecules have a number of potential advantages over conventional antibiotics, including reduced bacterial resistance, cost-effective preparation, and customizable designs. In this study, we investigate a family of nylon-3 polymer-based antimicrobials. By combining vesicle dye leakage, bacterial permeation, and bactericidal assays with small-angle X-ray scattering (SAXS), we find that these polymers are capable of two interdependent mechanisms of action: permeation of bacterial membranes and binding to intracellular targets such as DNA, with the latter necessarily dependent on the former. We systemically examine polymer-induced membrane deformation modes across a range of lipid compositions that mimic both bacteria and mammalian cell membranes. The results show that the polymers' ability to generate negative Gaussian curvature (NGC), a topological requirement for membrane permeation and cellular entry, in model Escherichia coli membranes correlates with their ability to permeate membranes without complete membrane disruption and kill E. coli cells. Our findings suggest that these polymers operate with a concentration-dependent mechanism of action: at low concentrations permeation and DNA binding occur without membrane disruption, while at high concentrations complete disruption of the membrane occurs. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins. Guest Editors: William C. Wimley and Kalina Hristova.

  14. Porcine antimicrobial peptides: new prospects for ancient molecules of host defense.

    Science.gov (United States)

    Zhang, G; Ross, C R; Blecha, F

    2000-01-01

    Antimicrobial peptides (AMPs) are small, endogenous, polycationic molecules that constitute a ubiquitous and significant component of innate immunity. These natural antibiotics have broad microbicidal activity against various bacteria, fungi, and enveloped viruses. Because most AMPs kill bacteria by physical disruption of cell membranes, which may prevent microorganisms from developing resistance against these agents, they are being explored as possible alternatives to conventional antibiotics. Pigs, like many other mammals, produce an impressive array of AMPs, which are synthesized predominantly by host leukocytic phagocytes or mucosal epithelial cells. Currently, more than a dozen distinct porcine AMPs have been identified and a majority belongs to the cathelicidin family. This review briefly summarizes recent advances in porcine AMP research with an emphasis on the diverse biological functions of each peptide. Mechanisms of action of these AMPs and their role in the resistance to infections are considered. Finally, the current status of pharmaceutical and agricultural uses of AMPs as well as future prospects for their application in the food animal industry is discussed.

  15. Safety Study of an Antimicrobial Peptide Lactocin 160, Produced by the Vaginal Lactobacillus rhamnosus

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    Sara E. Dover

    2007-01-01

    Full Text Available Objective. To evaluate the safety of the antimicrobial peptide, lactocin 160. Methods. Lactocin 160, a product of vaginal probiotic Lactobacillus rhamnosus 160 was evaluated for toxicity and irritation. An in vitro human organotypic vaginal-ectocervical tissue model (EpiVaginal was employed for the safety testing by determining the exposure time to reduce tissue viability to 50% (ET-50. Hemolytic activity of lactocin160 was tested using 8% of human erythrocyte suspension. Susceptibility of lactobacilli to lactocin160 was also studied. Rabbit vaginal irritation (RVI model was used for an in vivo safety evaluation. Results. The ET-50 value was 17.5 hours for lactocin 160 (4.9 hours for nonoxynol 9, N9. Hemolytic activity of lactocin 160 was 8.2% (N9 caused total hemolysis. Lactobacilli resisted to high concentrations of peptide preparation. The RVI model revealed slight vaginal irritation. An average irritation index grade was evaluated as “none.” Conclusions. Lactocin 160 showed minimal irritation and has a good potential for intravaginal application.

  16. Overexpression of antimicrobial lytic peptides protects grapevine from Pierce's disease under greenhouse but not field conditions.

    Science.gov (United States)

    Li, Zhijian T; Hopkins, Donald L; Gray, Dennis J

    2015-10-01

    Pierce's disease (PD) caused by Xylella fastidiosa prevents cultivation of grapevine (Vitis vinifera) and susceptible hybrids in the southeastern United States and poses a major threat to the grape industry of California and Texas. Genetic resistance is the only proven control of X. fastidiosa. Genetic engineering offers an alternative to heretofore ineffective conventional breeding in order to transfer only PD resistance traits into elite cultivars. A synthetic gene encoding lytic peptide LIMA-A was introduced into V. vinifera and a Vitis hybrid to assess in planta inhibition of X. fastidiosa. Over 1050 independent transgenic plant lines were evaluated in the greenhouse, among which nine lines were selected and tested under naturally-inoculated field conditions. These selected plant lines in the greenhouse remain disease-free for 10 years, to date, even with multiple manual pathogen inoculations. However, all these lines in the field, including a grafted transgenic rootstock, succumbed to PD within 7 years. We conclude that in planta production of antimicrobial lytic peptides does not provide durable PD resistance to grapevine under field conditions. PMID:25894660

  17. Covalent modification of a ten-residue cationic antimicrobial peptide with levofloxacin

    Science.gov (United States)

    Rodriguez, Carlos; Papanastasiou, Emilios; Juba, Melanie; Bishop, Barney

    2014-09-01

    The rampant spread of antibiotic resistant bacteria has spurred interest in alternative strategies for developing next-generation antibacterial therapies. As such, there has been growing interest in cationic antimicrobial peptides (CAMPs) and their therapeutic applications. Modification of CAMPs via conjugation to auxiliary compounds, including small molecule drugs, is a new approach to developing effective, broad-spectrum antibacterial agents with novel physicochemical properties and versatile antibacterial mechanisms. Here, we’ve explored design parameters for engineering CAMPs conjugated to small molecules with favorable physicochemical and antibacterial properties by covalently affixing a fluoroquinolone antibiotic, levofloxacin, to the ten-residue CAMP Pep-4. Relative to the unmodified Pep-4, the conjugate was found to demonstrate substantially increased antibacterial potency under high salt concentrations. Historically, it has been observed that most CAMPs lose antibacterial effectiveness in such high ionic strength environments, a fact that has presented a challenge to their development as therapeutics. Physicochemical studies revealed that P4LC was more hydrophobic than Pep-4, while mechanistic findings indicated that the conjugate was more effective at disrupting bacterial membrane integrity. Although the inherent antibacterial effect of the incorporated levofloxacin molecules did not appear to be substantially realized in this conjugate, these findings nevertheless suggest that covalent attachment of small molecule antibiotics with favorable physicochemical properties to CAMPs could be a promising strategy for enhancing peptide performance and overall therapeutic potential. These results have broader applicability to the development of future CAMP-antibiotic conjugates for potential therapeutic applications.

  18. Covalent modification of a ten-residue cationic antimicrobial peptide with levofloxacin

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    Carlos Alberto Rodriguez

    2014-09-01

    Full Text Available The rampant spread of antibiotic resistant bacteria has spurred interest in alternative strategies for developing next-generation antibacterial therapies. As such, there has been growing interest in cationic antimicrobial peptides (CAMPs and their therapeutic applications. Modification of CAMPs via conjugation to auxiliary compounds, including small molecule drugs, is a new approach to developing effective, broad-spectrum antibacterial agents with novel physicochemical properties and versatile antibacterial mechanisms. Here, we’ve explored design parameters for engineering CAMPs conjugated to small molecules with favorable physicochemical and antibacterial properties by covalently affixing a fluoroquinolone antibiotic, levofloxacin, to the ten-residue CAMP Pep-4. Relative to the unmodified Pep-4, the conjugate was found to demonstrate substantially increased antibacterial potency under high salt concentrations. Historically, it has been observed that most CAMPs lose antibacterial effectiveness in such high ionic strength environments, a fact that has presented a challenge to their development as therapeutics. Physicochemical studies revealed that P4LC was more hydrophobic than Pep-4, while mechanistic findings indicated that the conjugate was more effective at disrupting bacterial membrane integrity. Although the inherent antibacterial effect of the incorporated levofloxacin molecules did not appear to be substantially realized in this conjugate, these findings nevertheless suggest that covalent attachment of small molecule antibiotics with favorable physicochemical properties to CAMPs could be a promising strategy for enhancing peptide performance and overall therapeutic potential. These results have broader applicability to the development of future CAMP-antibiotic conjugates for potential therapeutic applications.

  19. Biocidal polymers: synthesis and antimicrobial properties of benzaldehyde derivatives immobilized onto amine-terminated polyacrylonitrile

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    Alamri Abdullah

    2012-10-01

    Full Text Available Abstract Background The design and applications of antimicrobial polymers is a growing field. Antimicrobial polymers can help to solve the problems associated with the use of conventional antimicrobial agents. Polymers with active functional groups can act as a carrier system for antimicrobial agents. In our study, we aim to prepare and develop some antimicrobial polymers for biomedical applications and water treatment. Results The antimicrobial polymers based on polyacrylonitrile (PAN were prepared. Functional groups were created onto polyacrylonitrile via amination using different types of diamines such as ethylenediamine (EDA and hexamethylenediamine (HMDA to yield amine-terminated polymers. Antimicrobial polymers were obtained by immobilization of benzaldehyde and its derivatives which include, 4-hydroxybenzaldehyde and 2,4-dihydroxybenzaldehyde onto amine-terminated polymers. The antimicrobial activity of the prepared polymers against different types of microorganisms including Gram-positive bacteria (Staphylococcus aureus, Gram-negative bacteria (Pseudomonas aeruginosa; Escherichia coli; and Salmonella typhi as well as fungi (Aspergillus flavus, Aspergillus niger, Candida albicans, Cryptpcoccus neoformans were explored by the cut plug method and viable cell counting methods. Conclusions Amine-terminated polyacrylonitrile were used as a novel polymeric carrier for benzaldehyde derivatives as antimicrobial agents. The prepared polymers can inhibit the growth of the microorganisms. The activity was varied according to the tested microorganism as well as the polymer microstructure. It was found that the activity increased with increasing the number phenolic hydroxyl group of the bioactive group. Finally, it is anticipated that the prepared antimicrobial polymers would be of great help in the field of biomedical applications and biological water treatment.

  20. Effects of the substitution of amino acid residues, through chemical synthesis, on the conformation and activity of antimicrobial peptides

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    Regina C. Adão

    2012-06-01

    Full Text Available Antimicrobial peptides make up an assorted group of molecules which contain from 12 to 50 amino acid residues and which may be produced by microorganisms, plants and animals. From the discovery that these biomolecules are lethal to bacteria, inhibiting the pathogenic organism’s growth, and are also related to innate and adapted defense mechanisms, the investigation of such molecules came to be an emergent research field, in which more than 1800 antimicrobial peptides have so far been discovered throughout the last three decades. These molecules are potential representatives of a new generation of antibiotic agents and the main motivation for such use is their activity against a wide variety of pathogens, including Gram-positive and Gram-negative bacteria as well as fungi and viruses. An important class of comprising some of these peptides may be found in anurans, from which it has been isolated, a considerable number of antimicrobial peptides with diverse sequences and structures, including linear and dimeric ones. In this work monomeric chains (CH1 e CH2 of the heterodimeric antimicrobial peptide distinctin (isolated in 1999 from Phyllomedusa distincta anurans, as well as its mutated monomers (CH1-S and CH2-S and the heterodimer itself were synthesized. The distinctin is the peptide with two chains of different sequences (Table 1 bound each other by disulfide bond from the cystein residues constituting the heterodimer. To investigate the effects on the biological activity by amino acids substitution at normal distinctin CH1 and CH2 chains, both were synthesized as well as their similar chains (CH1-S and CH2-S in which the cystein (Fig.1 a residues of each chain were changed by serin residues (Fig. 1 b. The new chains were named mutants. The synthesis was carried out in solid phase, using Fmoc strategy. The heterodimer distinctin was obtained from CH1 and CH2 chains coupling through cystein residues air oxidation. The results from HPLC