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Sample records for antimicrobial peptide repulsion

  1. Antimicrobial Peptides in 2014

    Directory of Open Access Journals (Sweden)

    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.

  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...... antimicrobial drugs, and computational methods utilizing molecular descriptors can significantly accelerate the development of new peptide drug candidates. Areas covered: This paper gives a broad overview of peptide and amino-acid scale descriptors available for AMP modeling and highlights which of these are...

  3. 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.

  4. Cationic Antimicrobial Peptide Cytotoxicity

    OpenAIRE

    Laverty, Garry; Gilmore, Brendan

    2014-01-01

    Fluorescence microscopy serves as a valuable tool for assessing the structural integrity and viability of eukaryotic cells. Through the use of calcein AM and the DNA stain 4,6-diamidino-2 phenylindole (DAPI), cell viability and membrane integrity can be qualified. Our group has previously shown the ultra-short cationic antimicrobial peptide H-OOWW-NH2; the amphibian derived 27-mer peptide Maximin-4and the ultra-short lipopeptide C12-OOWW-NH2 to be effective against a range of bacterial biofil...

  5. Antimicrobial peptides in crustaceans

    OpenAIRE

    RD Rosa; MA Barracco

    2010-01-01

    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 fam...

  6. Bacterial strategies of resistance to antimicrobial peptides.

    Science.gov (United States)

    Joo, Hwang-Soo; Fu, Chih-Iung; Otto, Michael

    2016-05-26

    Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160595

  7. 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

  8. 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.

  9. 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 ...

  10. 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.

  11. 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.

  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. 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

  14. Antimicrobial peptides in human skin disease

    OpenAIRE

    Kenshi, Yamasaki; Richard, L. Gallo

    2007-01-01

    The skin continuously encounters microbial pathogens. To defend against this, cells of the epidermis and dermis have evolved several innate strategies to prevent infection. Antimicrobial peptides are one of the primary mechanisms used by the skin in the early stages of immune defense. In general, antimicrobial peptides have broad antibacterial activity against gram-positive and negative bacteria and also show antifungal and antiviral activity. The antimicrobial activity of most peptides occur...

  15. 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.

  16. 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

  17. 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

  18. [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

  19. Study of antimicrobial peptides by capillary electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav

    Sofia: Bulgarian Peptide Society, 2015 - (Naydenova, E.; Pajpanova, T.; Danalev, D.), s. 304-305 ISBN 978-619-90427-2-4. [Peptides 2014. European Peptide Symposium /33./. Sofia (BG), 31.08.2014-05.09.2014] R&D Projects: GA ČR(CZ) GAP206/12/0453; GA ČR(CZ) GA13-17224S Institutional support: RVO:61388963 Keywords : peptides * antimicrobial activity * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation http://bulpepsoc.info/wp-content/uploads/2015/06/PEPTIDES-2014-electronic-version.pdf

  20. 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 ...

  1. 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

  2. Antimicrobial peptides in innate immune responses

    DEFF Research Database (Denmark)

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

    2008-01-01

    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......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...... 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...

  3. 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...

  4. 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...

  5. Novel properties of antimicrobial peptide anoplin

    Czech Academy of Sciences Publication Activity Database

    Jindřichová, Barbora; Burketová, Lenka; Novotná, Z.

    2014-01-01

    Roč. 444, č. 4 (2014), s. 520-524. ISSN 0006-291X R&D Projects: GA ČR GA522/09/1693 Institutional support: RVO:61389030 Keywords : Anoplin * Antimicrobial peptide * Antifungal Subject RIV: EE - Microbiology, Virology Impact factor: 2.297, year: 2014

  6. 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 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.

  7. Design and Application of Antimicrobial Peptide Conjugates.

    Science.gov (United States)

    Reinhardt, Andre; Neundorf, Ines

    2016-01-01

    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. PMID:27187357

  8. 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.

  9. 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

  10. Antimicrobial Peptides from Marine Proteobacteria

    OpenAIRE

    Yannick Fleury; Patrick Le Chevalier; Benjamin Brillet; Eric Balnois; Camille Jégou; Florie Desriac

    2013-01-01

    After years of inadequate use and the emergence of multidrug resistant (MDR) strains, the efficiency of “classical” antibiotics has decreased significantly. New drugs to fight MDR strains are urgently needed. Bacteria hold much promise as a source of unusual bioactive metabolites. However, the potential of marine bacteria, except for Actinomycetes and Cyanobacteria, has been largely underexplored. In the past two decades, the structures of several antimicrobial compounds have been elucidated ...

  11. 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.

  12. Analysis of antimicrobial peptides by capillary electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Ehala, Sille; Niederhafner, Petr; Čeřovský, Václav; Řezanka, P.; Sýkora, D.; Král, V.; Kašička, Václav

    Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 37-40 ISBN 978-80-86241-44-9. - (Collection Symposium Series. 13). [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] R&D Projects: GA ČR(CZ) GA203/09/0675; GA ČR(CZ) GA203/08/1428 Institutional research plan: CEZ:AV0Z40550506 Keywords : capillary electrophoresis * antimicrobial peptides * gold nanoparticles Subject RIV: CC - Organic Chemistry

  13. Antimicrobial peptides from plants and insects

    Czech Academy of Sciences Publication Activity Database

    Macková, Martina; Doležílková, Ivana; Neubauerová, Tereza; Ciencialová, Alice; Macek, Tomáš; Koutek, Bohumír; Jiráček, Jiří

    2007-01-01

    Roč. 7, č. 2 (2007), s. 26-27. ISSN 1213-6670. [Konference experimentální biologie rostlin, dny fyziologie rostlin /11./. 09.07.2007-12.07.2007, Olomouc] R&D Projects: GA ČR GA203/05/0832 Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptides * RP-HPLC * screening * fleshfly Subject RIV: CC - Organic Chemistry

  14. Membrane interactions of synthetic peptides with antimicrobial potential: effect of electrostatic interactions and amphiphilicity.

    Science.gov (United States)

    Fillion, Matthieu; Valois-Paillard, Geneviève; Lorin, Aurélien; Noël, Mathieu; Voyer, Normand; Auger, Michèle

    2015-03-01

    Cationic antimicrobial peptides are considered promising candidates to complement currently used antibiotics, which are less effective against increasingly resistant pathogens. To determine the mechanism of action of these peptides, a better understanding of each molecular determinant involved in their membrane interactions is of great importance. In this study, we have focused on the role of electrostatic interactions and amphiphilicity on the membrane interactions since the large majority of natural antimicrobial peptides are cationic. Therefore, cationic and anionic peptides have been prepared based on a model 14-mer peptide. The latter is a synthetic peptide composed of ten leucines and four phenylalanines, which are modified by the addition of the crown ether. Infrared spectroscopy results indicate that the position of substitution is the main determinant involved in the secondary structure adopted by the peptides, and not the charge of the substituted residues. Fluorescence vesicle leakage assays indicate, however, differences between the ability of cationic and anionic peptides to induce calcein release in zwitterionic and anionic lipid vesicles, suggesting an importance of electrostatic interactions and repulsions. Finally, (31)P NMR results indicate that the vesicle morphologies is not significantly affected by the interactions with both cationic and anionic peptides but that their effect on lipid bilayers is mainly determined by their secondary structure. This study therefore indicates that the membrane interactions of model 14-mer peptides are mainly governed by their secondary structure, which depends on the position of substitution, and not the charge of the residues. PMID:25422123

  15. 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.

  16. 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

  17. 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

  18. The Bacterial Surface Layer Provides Protection against Antimicrobial Peptides

    OpenAIRE

    de la Fuente-Núñez, César; Mertens, Jan; Smit, John; Hancock, Robert E. W.

    2012-01-01

    This report describes a previously unrecognized role for bacterial surface layers as barriers that confer protection against antimicrobial peptides. As antimicrobial peptides exist in natural environments, S-layers may provide a bacterial survival mechanism that has been selected for through evolution.

  19. 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

  20. 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.

  1. 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.

  2. Interaction between antimicrobial peptides and mycobacteria.

    Science.gov (United States)

    Gutsmann, Thomas

    2016-05-01

    Mycobacteria can cause different severe health problems, including tuberculosis (TB). The treatment of TB with conventional antibiotics is successful, however, the number of multi-drug and extensively-drug resistant Mycobacterium tuberculosis strains increases. Moreover, many classical antimycobacterial antibiotics have severe side effects. Therefore, antimicrobial peptides (AMPs) seem to be good candidates for new therapeutic strategies. On the one hand AMPs can be used as a single drug or in combination with conventional antibiotics to directly kill mycobacteria, or on the other hand to act as immunstimulatory agents. This review summarizes the findings on the role of endogenous human AMPs being involved in TB, the antimycobacterial activity of various AMPs, and the molecular modes of action. Most active AMPs interact with the mycobacterial cell envelope and in particular with the mycomembrane and the plasma membrane. The mycomembrane is a very rigid membrane probably leading to a lower activity of the AMPs against mycobacteria as compared to other Gram-negative or Gram-positive bacteria. For some AMPs also other targets have been identified. Because of the complex environment of intracellular mycobacteria being trapped in the phagosome, within the macrophage, within the granuloma, within the lung, the external administration of AMPs in the latent phase of TB is a challenge. However, in the acute phase the AMPs can attack mycobacteria in a direct way. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. PMID:26851776

  3. 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.

  4. 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.

  5. 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.

  6. Salivary Antimicrobial Peptide Expression and Dental Caries Experience in Children

    OpenAIRE

    Tao, Renchuan; Jurevic, Richard J.; Coulton, Kimberly K.; Tsutsui, Marjorie T.; Roberts, Marilyn C.; Kimball, Janet R.; Wells, Norma; Berndt, Jeffery; Dale, Beverly A.

    2005-01-01

    Dental caries is a major worldwide oral disease problem in children. Although caries are known to be influenced by dietary factors, the disease results from a bacterial infection; thus, caries susceptibility may be affected by host factors such as salivary antimicrobial peptides. This study aimed to determine a possible correlation between caries prevalence in children and salivary concentrations of the antimicrobial peptides human beta-defensin-3 (hBD-3), the cathelicidin LL37, and the alpha...

  7. 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.

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

    DEFF Research Database (Denmark)

    Ebbensgaard, Anna Elisabeth; Mordhorst, Hanne; Overgaard, Michael Toft;

    2015-01-01

    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...... among the different peptides. Further, the antimicrobial activity of a selection of cationic AMPs was investigated in various E. coli LPS mutants....

  9. 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.

  10. 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

    Simulations of antimicrobial peptides in membrane mimics can provide the high resolution, atomistic picture that is necessary to decipher which sequence and structure components are responsible for activity and toxicity. With such detailed insight, engineering new sequences that are active but non...... 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...... classes of peptides, helical and beta-sheet and demonstrate how simulations can assist in engineering of novel antimicrobials with therapeutic potential....

  11. 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

  12. Novel antimicrobial peptides from the venom of solitary bees

    Czech Academy of Sciences Publication Activity Database

    Čeřovský, Václav; Cvačka, Josef; Voburka, Zdeněk; Hovorka, Oldřich; Slaninová, Jiřina; Fučík, Vladimír; Bednárová, Lucie

    2008-01-01

    Roč. 14, č. 8 (2008), s. 92-92. ISSN 1075-2617. [European Peptide Symposium /30./. 31.08.2008-05.09.2008, Helsinki] Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptides * solitary bees * melectin * isolation and characterization Subject RIV: CC - Organic Chemistry

  13. 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

  14. An anionic antimicrobial peptide from toad Bombina maxima.

    Science.gov (United States)

    Lai, Ren; Liu, Hen; Hui Lee, Wen; Zhang, Yun

    2002-07-26

    Amphibian skin is a rich resource of antimicrobial peptides like maximins and maximins H from toad Bombina maxima. A novel cDNA clone encoding a precursor protein that comprises maximin 3 and a novel peptide, named maximin H5, was isolated from a skin cDNA library of B. maxima. The predicted primary structure of maximin H5 is ILGPVLGLVSDTLDDVLGIL-NH2. Containing three aspartate residues and no basic amino acid residues, maximin H5 is characterized by an anionic property. Different from cationic maximin H peptides, only Gram-positive strain Staphylococcus aureus was sensitive to maximin H5, while the other bacterial and fungal strains tested were resistant to it. The presence of metal ions, like Zn2+ and Mg2+, did not increase its antimicrobial potency. Maximin H5 represents the first example of potential anionic antimicrobial peptides from amphibians. The results provide the first evidence that, together with cationic antimicrobial peptides, anionic antimicrobial peptides may also exist naturally as part of the innate defense system. PMID:12127963

  15. 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 und...... three canonical antimicrobial peptides: melittin, magainin 2, and mastoparan X. The results demonstrate an unprecedented level of insight into the molecular processes governing antimicrobial peptide-induced permeabilization of phospholipid membranes....

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

    Directory of Open Access Journals (Sweden)

    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.

  17. Evolution of antimicrobial peptides to self-assembled peptides for biomaterial applications.

    Science.gov (United States)

    McCloskey, Alice P; Gilmore, Brendan F; Laverty, Garry

    2014-01-01

    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. PMID:25436505

  18. 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

  19. Identification of novel human immunodeficiency virus type 1-inhibitory peptides based on the antimicrobial peptide database.

    Science.gov (United States)

    Wang, Guangshun; Watson, Karen M; Peterkofsky, Alan; Buckheit, Robert W

    2010-03-01

    To identify novel anti-HIV-1 peptides based on the antimicrobial peptide database (APD; http://aps.unmc.edu/AP/main.php), we have screened 30 candidates and found 11 peptides with 50% effective concentrations (EC(50)) of 1, increases in the Arg contents of amphibian maximin H5 and dermaseptin S9 peptides and the database-derived GLK-19 peptide improved the TIs. These examples demonstrate that the APD is a rich resource and a useful tool for developing novel HIV-1-inhibitory peptides. PMID:20086159

  20. Design of stable antimicrobial peptides through hydrocarbon stapling

    Czech Academy of Sciences Publication Activity Database

    Chapuis, Hubert Jean; Slaninová, Jiřina; Monincová, Lenka; Bednárová, Lucie; Čeřovský, Václav

    Praha: Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 19-21. (Collection Symposium Series. 13). ISBN 978-80-86241-44-9. [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] R&D Projects: GA ČR GA203/08/0536 Institutional research plan: CEZ:AV0Z40550506 Keywords : amphipathic alpha-helices * antimicrobial peptides * peptide synthesis * ring closing metathesis ( RCM ) * peptide stapling Subject RIV: CC - Organic Chemistry

  1. 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...

  2. 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...

  3. Quantitative studies of antimicrobial peptide-lipid membrane interactions

    DEFF Research Database (Denmark)

    Kristensen, Kasper

    three archetypal α-helical antimicrobial peptides mastoparan X, melittin, and magainin 2 as model peptides. These three peptides are investigated by three different experimental techniques. The first of these experimental techniques is analytical HPLC. We use this technique to document an effect that...... X, melittin and magainin 2. Consequently, we conclude that investigators should always take this adsorptive effect into account when designing and interpreting their experiments on antimicrobial peptides. The second experimental technique is fluorescence correlation spectroscopy (FCS). We optimize....... We demonstrate the applicability of FCS by using the technique to study partial transient leakage induced by mastoparan X, melittin, and magainin 2. The leakage data demonstrate that magainin 2 forms larger and/or more stable transmembrane pores in POPC/POPG (3:1) lipid bilayers than do mastoparan X...

  4. 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...

  5. Cationic Antimicrobial Peptides Disrupt the Streptococcus pyogenes ExPortal

    OpenAIRE

    Vega, Luis Alberto; Caparon, Michael G.

    2012-01-01

    Although they possess a well-characterized ability to porate the bacterial membrane, emerging research suggests that cationic antimicrobial peptides (CAPs) can influence pathogen behavior at levels that are sub-lethal. In this study, we investigated the interaction of polymyxin B and human neutrophil peptide (HNP-1) with the human pathogen Streptococcus pyogenes. At sub-lethal concentrations, these CAPs preferentially targeted the ExPortal, a unique microdomain of the S. pyogenes membrane, sp...

  6. 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.

  7. 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. ...

  8. 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

  9. 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...

  10. Novel antimicrobial peptides isolated from the venom of wild bees

    Czech Academy of Sciences Publication Activity Database

    Čeřovský, Václav; Monincová, Lenka; Slaninová, Jiřina; Fučík, Vladimír; Borovičková, Lenka; Hovorka, Oldřich; Voburka, Zdeněk; Cvačka, Josef; Bednárová, Lucie; Buděšínský, Miloš; Straka, J.

    2009-01-01

    Roč. 276, Suppl. 1 (2009), s. 106-106. ISSN 1742-464X. [FEBS Congress /34/. 04.07.2009-09.07.2009, Praha] Institutional research plan: CEZ:AV0Z40550506 Keywords : linear cationic alpha-helical antimicrobial peptides * Edman degradation * mass spectrometry Subject RIV: CC - Organic Chemistry

  11. 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

  12. Determination of acidity constants of antimicrobial peptides by capillary electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav

    2015-01-01

    Roč. 44, Suppl 1 (2015), S130. ISSN 0175-7571. [EBSA European Biophysics Congress /10./. 18.07.2015-22.07.2015, Dresden] R&D Projects: GA ČR(CZ) GA13-17224S Institutional support: RVO:61388963 Keywords : acidity constant * antimicrobial peptides * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation

  13. Isolation of antimicrobial peptides and proteins from tomato

    Czech Academy of Sciences Publication Activity Database

    Králová, M.; Šanda, Miloslav; Macková, M.; Macek, Tomáš

    Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 73-76 ISBN 978-80-86241-44-9. - (Collection Symposium Series. 13). [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] Grant ostatní: GA ČR(CZ) GA522/09/1693; GA ČR(CZ) GD305/09/H008 Institutional research plan: CEZ:AV0Z40550506 Keywords : tomato * antimicrobial peptides * plant peptide isolation Subject RIV: CC - Organic Chemistry

  14. Natural antimicrobial peptides as promising anti-HIV candidates

    Science.gov (United States)

    Wang, Guangshun

    2015-01-01

    Human immunodeficiency virus type 1 (HIV-1) infection remains to be one of the major global health problems. It is thus necessary to identify novel therapeutic molecules to combat HIV-1. Natural antimicrobial peptides (AMPs) have been recognized as promising templates for developing topical microbicides. This review systematically discusses over 80 anti-HIV peptides annotated in the antimicrobial peptide database (http://aps.unmc.edu/AP). Such peptides have been discovered from bacteria, plants, and animals. Examples include gramicidin and bacteriocins from bacteria, cyclotides from plants, melittins and cecropins from insects, piscidins from fish, ascaphins, caerins, dermaseptins, esculentins, and maximins from amphibians, and cathelicidins and defensins from vertebrates. These peptides appear to work by different mechanisms and could block viral entry in multiple ways. As additional advantages, such anti-HIV peptides may possess other desired features such as antibacterial, antiparasital, spermicidal, and anticancer activity. With continued optimization of peptide stability, production, formulation and delivery methods, it is anticipated that some of these compounds may eventually become new anti-HIV drugs. PMID:26834391

  15. Antimicrobial beta-peptides and alpha-peptoids

    DEFF Research Database (Denmark)

    Godballe, Troels; Nilsson, Line L.; Petersen, Pernille D.;

    2011-01-01

    The field of drug discovery and development has seen tremendous activity over the past decade to better tackle the increasing occurrence of drugresistant bacterial infections and to alleviate some of the pressure we put on the last-resort drugs on the market. One of the new and promising drug...... candidates is derived from naturally occurring antimicrobial peptides. However, despite promising results in early-stage clinical trials, these molecules have faced some difficulties securing FDA approval, which can be linked to their poor metabolic stability. Hence, mimetics of these antimicrobial peptides...... have been suggested as new templates for antibacterial compound design, because these mimetics are resistant against degradation by proteases. This review will discuss the structural features of two different types of mimetics, b-peptides and a-peptoids, in relation to their antibacterial activity and...

  16. 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.

  17. There are abundant antimicrobial peptides in brains of two kinds of Bombina toads.

    Science.gov (United States)

    Liu, Rui; Liu, Huan; Ma, Yufang; Wu, Jing; Yang, Hailong; Ye, Huahu; Lai, Ren

    2011-04-01

    It is well-known that there is a large amount of antimicrobial peptides in amphibian skins but few antimicrobial peptides are found in amphibian brains. Twenty-two and four antimicrobial peptides were purified and characterized from the brain homogenate of Bombina maxima and B. microdeladigitora, respectively. One hundred fifty-eight cDNA clones encoding 79 antimicrobial peptides were isolated from brain cDNA libraries of B. maxima and B. microdeladigitora. These antimicrobial peptides belong to two peptide groups (maximin and maximin-H). Twenty of them are identical to previously reported antimicrobial peptides (maximin 1-8, 10, 11, maximin H1, 3-5, 7, 9, 10, 12, 15, 16) from B. maxima skin secretions. Fifty-nine of them are novel antimicrobial peptides. Some of these antimicrobial peptides showed strong antimicrobial activities against tested microorganism strains including Gram-positive and -negative bacteria and fungi. The current diversity in peptide coding cDNA sequences is, to our knowledge, the most extreme yet described for any animal brains. The extreme diversity may give rise to interest to prospect the actual functions of antimicrobial peptides in amphibian brains. PMID:21338048

  18. 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

  19. Bacterial resistance to antimicrobial peptides: an evolving phenomenon.

    Science.gov (United States)

    Fleitas, Osmel; Agbale, Caleb M; Franco, Octavio L

    2016-01-01

    Bacterial resistance to conventional antibiotics is currently a real problem all over the world, making novel antimicrobial compounds a real research priority. Some of the most promising compounds found to date are antimicrobial peptides (AMPs). The benefits of these drugs include their broad spectrum of activity that affects several microbial processes, making the emergence of resistance less likely. However, bacterial resistance to AMPs is an evolving phenomenon that compromises the therapeutic potential of these compounds. Therefore, it is mandatory to understand bacterial mechanisms of resistance to AMPs in depth, in order to develop more powerful AMPs that overcome the bacterial resistance response. PMID:27100488

  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. Biofilm Induced Tolerance Towards Antimicrobial Peptides

    DEFF Research Database (Denmark)

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

    2008-01-01

    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...

  2. Inhibition of Escherichia coli ATP synthase by amphibian antimicrobial peptides.

    Science.gov (United States)

    Laughlin, Thomas F; Ahmad, Zulfiqar

    2010-04-01

    Previously melittin, the alpha-helical basic honey bee venom peptide, was shown to inhibit F(1)-ATPase by binding at the beta-subunit DELSEED motif of F(1)F(o)-ATP synthase. Herein, we present the inhibitory effects of the basic alpha-helical amphibian antimicrobial peptides, ascaphin-8, aurein 2.2, aurein 2.3, carein 1.8, carein 1.9, citropin 1.1, dermaseptin, maculatin 1.1, maganin II, MRP, or XT-7, on purified F(1) and membrane bound F(1)F(0)Escherichia coli ATP synthase. We found that the extent of inhibition by amphibian peptides is variable. Whereas MRP-amide inhibited ATPase essentially completely (approximately 96% inhibition), carein 1.8 did not inhibit at all (0% inhibition). Inhibition by other peptides was partial with a range of approximately 13-70%. MRP-amide was also the most potent inhibitor on molar scale (IC(50) approximately 3.25 microM). Presence of an amide group at the c-terminal of peptides was found to be critical in exerting potent inhibition of ATP synthase ( approximately 20-40% additional inhibition). Inhibition was fully reversible and found to be identical in both F(1)F(0) membrane preparations as well as in isolated purified F(1). Interestingly, growth of E. coli was abrogated in the presence of ascaphin-8, aurein 2.2, aurein 2.3, citropin 1.1, dermaseptin, magainin II-amide, MRP, MRP-amide, melittin, or melittin-amide but was unaffected in the presence of carein 1.8, carein 1.9, maculatin 1.1, magainin II, or XT-7. Hence inhibition of F(1)-ATPase and E. coli cell growth by amphibian antimicrobial peptides suggests that their antimicrobial/anticancer properties are in part linked to their actions on ATP synthase. PMID:20100509

  3. Isolation of antimicrobial peptides and proteins from tomato

    Czech Academy of Sciences Publication Activity Database

    Králová, M.; Šanda, Miloslav; Macková, M.; Macek, Tomáš

    Praha : Ústav organické chemie a biochemie AV ČR, v.v.i, 2011 - (Slaninová, J.; Borovičková, L.). s. 41-41 ISBN 978-80-86241-36-4. [Biologically Active Peptides /12./. 27.04.2011-29.04.2011, Praha] R&D Projects: GA ČR GD305/09/H008 Grant ostatní: GA ČR(CZ) GA522/09/1693 Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptides * isolation * tomato Subject RIV: CC - Organic Chemistry

  4. Study of antimicrobial peptide induction in Brassica napus

    Czech Academy of Sciences Publication Activity Database

    Shevchenko, I.; Neubauerová, Tereza; Macková, Martina; Macek, Tomáš

    Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 127-129 ISBN 978-80-86241-44-9. - (Collection Symposium Series. 13). [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] Grant ostatní: GA ČR(CZ) GA522/09/1693; GA ČR(CZ) GD305/09/H008 Institutional research plan: CEZ:AV0Z40550506 Keywords : Brassica napus * induced resistance * antimicrobial peptides Subject RIV: CC - Organic Chemistry

  5. 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

  6. Analysis and characterization of antimicrobial peptides by capillary electromigration methods

    Czech Academy of Sciences Publication Activity Database

    Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav

    Prague: Charles University in Prague, Faculty of Science, 2014 - (Nesměrák, K.), s. 78-79 ISBN 978-80-7444-030-4. [International Students Conference "Modern Analytical Chemistry" /10./. Praha (CZ), 22.09.2014-23.09.2014] R&D Projects: GA ČR(CZ) GAP206/12/0453; GA ČR(CZ) GA13-17224S Institutional support: RVO:61388963 Keywords : antimicrobial peptides * capillary electrophoresis * coating Subject RIV: CB - Analytical Chemistry, Separation

  7. 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...

  8. 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 ...

  9. Context mediates antimicrobial efficacy of kinocidin congener peptide RP-1.

    Directory of Open Access Journals (Sweden)

    Nannette Y Yount

    Full Text Available Structure-mechanism relationships are key determinants of host defense peptide efficacy. These relationships are influenced by anatomic, physiologic and microbiologic contexts. Structure-mechanism correlates were assessed for the synthetic peptide RP-1, modeled on microbicidal domains of platelet kinocidins. Antimicrobial efficacies and mechanisms of action against susceptible ((S or resistant ((R Salmonella typhimurium (ST, Staphylococcus aureus (SA, and Candida albicans (CA strain pairs were studied at pH 7.5 and 5.5. Although RP-1 was active against all study organisms, it exhibited greater efficacy against bacteria at pH 7.5, but greater efficacy against CA at pH 5.5. RP-1 de-energized SA and CA, but caused hyperpolarization of ST in both pH conditions. However, RP-1 permeabilized ST(S and CA strains at both pH, whereas permeabilization was modest for ST(R or SA strain at either pH. Biochemical analysis, molecular modeling, and FTIR spectroscopy data revealed that RP-1 has indistinguishable net charge and backbone trajectories at pH 5.5 and 7.5. Yet, concordant with organism-specific efficacy, surface plasmon resonance, and FTIR, molecular dynamics revealed modest helical order increases but greater RP-1 avidity and penetration of bacterial than eukaryotic lipid systems, particularly at pH 7.5. The present findings suggest that pH- and target-cell lipid contexts influence selective antimicrobial efficacy and mechanisms of RP-1 action. These findings offer new insights into selective antimicrobial efficacy and context-specificity of antimicrobial peptides in host defense, and support design strategies for potent anti-infective peptides with minimal concomitant cytotoxicity.

  10. 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...

  11. 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.

  12. 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.

  13. 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

  14. Avian antimicrobial host defense peptides: from biology to therapeutic applications.

    Science.gov (United States)

    Zhang, Guolong; Sunkara, Lakshmi T

    2014-01-01

    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. PMID:24583933

  15. A synthetic peptide adhesion epitope as a novel antimicrobial agent.

    Science.gov (United States)

    Kelly, C G; Younson, J S; Hikmat, B Y; Todryk, S M; Czisch, M; Haris, P I; Flindall, I R; Newby, C; Mallet, A I; Ma, J K; Lehner, T

    1999-01-01

    The earliest step in microbial infection is adherence by specific microbial adhesins to the mucosa of the oro-intestinal, nasorespiratory, or genitourinary tract. We inhibited binding of a cell surface adhesin of Streptococcus mutans to salivary receptors in vitro, as measured by surface plasmon resonance, using a synthetic peptide (p1025) corresponding to residues 1025-1044 of the adhesin. Two residues within p1025 that contribute to binding (Q1025, E1037) were identified by site-directed mutagenesis. In an in vivo human streptococcal adhesion model, direct application of p1025 to the teeth prevented recolonization of S. mutans but not Actinomyces, as compared with a control peptide or saline. This novel antimicrobial strategy, applying competitive peptide inhibitors of adhesion, may be used against other microorganisms in which adhesins mediate colonization of mucosal surfaces. PMID:9920267

  16. 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.

  17. 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.

  18. 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

  19. 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.

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

    Science.gov (United States)

    Katzenback, Barbara A

    2015-01-01

    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. PMID:26426065

  1. 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.

  2. Mammalian antimicrobial peptide influences control of cutaneous Leishmania infection

    Science.gov (United States)

    Kulkarni, Manjusha M.; Barbi, Joseph; McMaster, W. Robert; Gallo, Richard L.; Satoskar, Abhay R.; McGwire, Bradford S.

    2011-01-01

    Summary Cathelicidin-type antimicrobial peptides (CAMP) are important mediators of innate immunity against microbial pathogens acting through direct interaction with and disruption of microbial membranes and indirectly through modulation of host cell migration and activation. Using a mouse knock-out model in CAMP we studied the role of this host peptide in control of dissemination of cutaneous infection by the parasitic protozoan Leishmania. The presence of pronounced host inflammatory infiltration in lesions and lymph nodes of infected animals was CAMP-dependent. Lack of CAMP expression was associated with higher levels of IL-10 receptor expression in bone marrow, splenic and lymph node macrophages as well as higher anti-inflammatory IL-10 production by bone marrow macrophages and spleen cells but reduced production of the pro-inflammatory cytokines IL-12 and IFN-γ by lymph nodes. Unlike wild-type mice, local lesions were exacerbated and parasites were found largely disseminated in CAMP knockouts. Infection of CAMP knockouts with parasite mutants lacking the surface metalloprotease virulence determinant resulted in more robust disseminated infection than in control animals suggesting that CAMP activity is negatively regulated by parasite surface proteolytic activity. This correlated with the ability of the pro-tease to degrade CAMP in vitro and co-localization of CAMP with parasites within macrophages. Our results highlight the interplay of antimicrobial peptides and Leishmania that influence the host immune response and the outcome of infection. PMID:21501359

  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. 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

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

    DEFF Research Database (Denmark)

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

    understanding of their interactions with phospholipid membranes. In this study, the membrane-permeabilizing effects of antimicrobial peptides were scrutinized by combining two biophysical techniques. Confocal fluorescence microscopy to visualize leakage from individual surface-immobilized lipid vesicles was......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...... three canonical antimicrobial peptides: melittin, magainin 2, and mastoparan X. The results demonstrate an unprecedented level of insight into the molecular processes governing antimicrobial peptide-induced permeabilization of phospholipid membranes....

  6. Spermicidal Activity of the Safe Natural Antimicrobial Peptide Subtilosin

    Directory of Open Access Journals (Sweden)

    Michael L. Chikindas

    2008-10-01

    Full Text Available Bacterial vaginosis (BV, a condition affecting millions of women each year, is primarily caused by the gram-variable organism Gardnerella vaginalis. A number of organisms associated with BV cases have been reported to develop multidrug resistance, leading to the need for alternative therapies. Previously, we reported the antimicrobial peptide subtilosin has proven antimicrobial activity against G. vaginalis, but not against the tested healthy vaginal microbiota of lactobacilli. After conducting tissue sensitivity assays using an ectocervical tissue model, we determined that human cells remained viable after prolonged exposures to partially-purified subtilosin, indicating the compound is safe for human use. Subtilosin was shown to eliminate the motility and forward progression of human spermatozoa in a dose-dependent manner, and can therefore be considered a general spermicidal agent. These results suggest subtilosin would be a valuable component in topical personal care products aimed at contraception and BV prophylaxis and treatment.

  7. 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

  8. 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

  9. Antimicrobial peptide genes in Bacillus strains from plant environments

    OpenAIRE

    Mora Pons, Isabel; Cabrefiga Olamendi, Jordi; Montesinos Seguí, Emilio

    2011-01-01

    The presence of the antimicrobial peptide (AMP) biosynthetic genes srfAA (surfactin), bacA (bacylisin), fenD (fengycin), bmyB (bacyllomicin), spaS (subtilin), and ituC (iturin) was examined in 184 isolates of Bacillus spp. obtained from plant environments (aerial, rhizosphere, soil) in the Mediterranean land area of Spain. Most strains had between two and four AMP genes whereas strains with five genes were seldom detected and none of the strains had six genes. The most frequent AMP gene marke...

  10. Recombinant expression and activity of cationic antimicrobial peptides

    OpenAIRE

    Ramos, Reinaldo Rodrigues

    2011-01-01

    Nos últimos 60 anos, os antibióticos têm sido cruciais no combate contra doenças infecciosas causadas por microrganismos. A resistência crescente destes microrganismos aos antibióticos tornou-se um sério problema de saúde pública. Para combater esta situação, muita investigação tem sido desenvolvida para produzir novos tipos de antibióticos. Os péptidos antimicrobianos (Antimicrobial Peptides - AMPs) são geralmente definidos como péptidos com menos de 50 aminoácidos, com carga ...

  11. 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

  12. 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 ...

  13. Protocols to test the activity of antimicrobial peptides against the honey bee pathogen Paenibacillus larvae.

    Science.gov (United States)

    Khilnani, Jasmin C; Wing, Helen J

    2015-10-01

    Paenibacillus larvae is the causal agent of the honey bee disease American Foulbrood. Two enhanced protocols that allow the activity of antimicrobial peptides to be tested against P. larvae are presented. Proof of principle experiments demonstrate that the honey bee antimicrobial peptide defensin 1 is active in both assays. PMID:26210039

  14. Antimicrobial peptides from frog skin: biodiversity and therapeutic promises.

    Science.gov (United States)

    Ladram, Ali; Nicolas, Pierre

    2016-01-01

    More than a thousand antimicrobial peptides (AMPs) have been reported in the last decades arising from the skin secretion of amphibian species. Generally, each frog species can express its own repertoire of AMPs (typically, 10-20 peptides) with differing sequences, sizes, and spectrum of action, which implies very rapid divergence, even between closely related species. Frog skin AMPs are highly potent against antibiotic-resistant bacteria, protozoa, yeasts, and fungi by permeating and destroying their plasma membrane and/or inactivating intracellular targets. These peptides have attracted considerable interest as a therapeutic alternative to conventional anti-infective agents. However, efforts to obtain a new generation of drugs using these peptides are still challenging because of high associated R&D costs due to their large size (up to 46 residues) and cytotoxicity. This review deals with the biodiversity of frog skin AMPs and assesses the therapeutic possibilities of temporins, the shortest AMPs found in the frog skin, with 8-17 residues. Such short sequences are easily amenable to optimization of the structure and to solution-phase synthesis that offer reduced costs over solid-phase chemistry. PMID:27100511

  15. The effect of amidation on the behaviour of antimicrobial peptides.

    Science.gov (United States)

    Mura, Manuela; Wang, Jianping; Zhou, Yuhua; Pinna, Marco; Zvelindovsky, Andrei V; Dennison, Sarah R; Phoenix, David A

    2016-04-01

    Aurein 2.6-COOH and aurein 3.1-COOH were studied along with their naturally occurring C-terminally amidated analogues. Circular dichroism (CD) and molecular dynamic (MD) simulations were used to study the effects of amidation on the interaction of antimicrobial peptides (AMPs) with lipid bilayers. CD measurements and MD analysis suggested that both peptide analogues were predominantly random coil and adopted low levels of [Formula: see text]-helical structure in solution (peptides formed a stable [Formula: see text]-helical structure. In general, amidated analogues have a greater propensity than the non-amidated peptides to form a [Formula: see text]-helical structure. MD simulations predicted that aurein 2.6-COOH and aurein 3.1-CHOOH destabilised lipid bilayers from 1,2-dimyristoyl-sn-glycero-3-phosphocholine and 1,2-dimyristoyl-sn-glycero-3-phosphoserine via angled bilayer penetration. They also showed that aurein 2.6-CONH[Formula: see text] and aurein 3.1-CONH[Formula: see text] formed a helix horizontal to the plane of an asymmetric interface. PMID:26745958

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

    OpenAIRE

    Chen Jianzhu; Har Jia; Leptihn Sebastian; Ho Bow; Wohland Thorsten; Ding Jeak

    2009-01-01

    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 pathoge...

  17. 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.

  18. Analysis of the antimicrobial activities of a chemokine-derived peptide (CDAP-4) on Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Chemokines are key molecules involved in the control of leukocyte trafficking. Recently, a novel function as antimicrobial proteins has been described. CCL13 is the only member of the MCP chemokine subfamily displaying antimicrobial activity. To determine Key residues involved in its antimicrobial activity, CCL13 derived peptides were synthesized and tested against several bacterial strains, including Pseudomonas aeruginosa. One of these peptides, corresponding to the C-terminal region of CCL13 (CDAP-4) displayed good antimicrobial activity. Electron microscopy studies revealed remarkable morphological changes after CDAP-4 treatment. By computer modeling, CDAP-4 in α helical configuration generated a positive electrostatic potential that extended beyond the surface of the molecule. This feature is similar to other antimicrobial peptides. Altogether, these findings indicate that the antimicrobial activity was displayed by CCL13 resides to some extent at the C-terminal region. Furthermore, CDAP-4 could be considered a good antimicrobial candidate with a potential use against pathogens including P. aeruginosa

  19. Antimicrobial peptides and cell processes tracking endosymbiont dynamics.

    Science.gov (United States)

    Masson, Florent; Zaidman-Rémy, Anna; Heddi, Abdelaziz

    2016-05-26

    Many insects sustain long-term relationships with intracellular symbiotic bacteria that provide them with essential nutrients. Such endosymbiotic relationships likely emerged from ancestral infections of the host by free-living bacteria, the genomes of which experience drastic gene losses and rearrangements during the host-symbiont coevolution. While it is well documented that endosymbiont genome shrinkage results in the loss of bacterial virulence genes, whether and how the host immune system evolves towards the tolerance and control of bacterial partners remains elusive. Remarkably, many insects rely on a 'compartmentalization strategy' that consists in secluding endosymbionts within specialized host cells, the bacteriocytes, thus preventing direct symbiont contact with the host systemic immune system. In this review, we compile recent advances in the understanding of the bacteriocyte immune and cellular regulators involved in endosymbiont maintenance and control. We focus on the cereal weevils Sitophilus spp., in which bacteriocytes form bacteriome organs that strikingly evolve in structure and number according to insect development and physiological needs. We discuss how weevils track endosymbiont dynamics through at least two mechanisms: (i) a bacteriome local antimicrobial peptide synthesis that regulates endosymbiont cell cytokinesis and helps to maintain a homeostatic state within bacteriocytes and (ii) some cellular processes such as apoptosis and autophagy which adjust endosymbiont load to the host developmental requirements, hence ensuring a fine-tuned integration of symbiosis costs and benefits.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160600

  20. Antimicrobial peptides in marine invertebrate health and disease.

    Science.gov (United States)

    Destoumieux-Garzón, Delphine; Rosa, Rafael Diego; Schmitt, Paulina; Barreto, Cairé; Vidal-Dupiol, Jeremie; Mitta, Guillaume; Gueguen, Yannick; Bachère, Evelyne

    2016-05-26

    Aquaculture contributes more than one-third of the animal protein from marine sources worldwide. A significant proportion of aquaculture products are derived from marine protostomes that are commonly referred to as 'marine invertebrates'. Among them, penaeid shrimp (Ecdysozosoa, Arthropoda) and bivalve molluscs (Lophotrochozoa, Mollusca) are economically important. Mass rearing of arthropods and molluscs causes problems with pathogens in aquatic ecosystems that are exploited by humans. Remarkably, species of corals (Cnidaria) living in non-exploited ecosystems also suffer from devastating infectious diseases that display intriguing similarities with those affecting farmed animals. Infectious diseases affecting wild and farmed animals that are present in marine environments are predicted to increase in the future. This paper summarizes the role of the main pathogens and their interaction with host immunity, with a specific focus on antimicrobial peptides (AMPs) and pathogen resistance against AMPs. We provide a detailed review of penaeid shrimp AMPs and their role at the interface between the host and its resident/pathogenic microbiota. We also briefly describe the relevance of marine invertebrate AMPs in an applied context.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160602

  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 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 ...

  3. 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.

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

    International Nuclear Information System (INIS)

    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. Controlling the release of peptide antimicrobial agents from surfaces.

    Science.gov (United States)

    Shukla, Anita; Fleming, Kathleen E; Chuang, Helen F; Chau, Tanguy M; Loose, Christopher R; Stephanopoulos, Gregory N; Hammond, Paula T

    2010-03-01

    Medical conditions are often exacerbated by the onset of infection caused by hospital dwelling bacteria such as Staphylococcus aureus. Antibiotics taken orally or intravenously can require large and frequent doses, further contributing to the sharp rise in resistant bacteria observed over the past several decades. These existing antibiotics are also often ineffective in preventing biofilm formation, a common cause of medical device failure. Local delivery of new therapeutic agents that do not allow bacterial resistance to occur, such as antimicrobial peptides, could alleviate many of the problems associated with current antibacterial treatments. By taking advantage of the versatility of layer-by-layer assembly of polymer thin films, ponericin G1, an antimicrobial peptide known to be highly active against S. aureus, was incorporated into a hydrolytically degradable polyelectrolyte multilayer film. Several film architectures were examined to obtain various drug loadings that ranged from 20 to 150 microg/cm2. Release was observed over approximately ten days, with varying release profiles, including burst as well as linear release. Results indicated that film-released peptide did not suffer any loss in activity against S. aureus and was able to inhibit bacteria attachment, a necessary step in preventing biofilm formation. Additionally, all films were found to be biocompatible with the relevant wound healing cells, NIH 3T3 fibroblasts and human umbilical vein endothelial cells. These films provide the level of control over drug loading and release kinetics required in medically relevant applications including coatings for implant materials and bandages, while eliminating susceptibility to bacterial resistance. PMID:20004967

  7. 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...

  8. Relative free energy of binding between antimicrobial peptides and SDS or DPC micelles

    OpenAIRE

    Sayyed-Ahmad, Abdallah; Khandelia, Himanshu; Kaznessis, Yiannis N.

    2009-01-01

    We present relative binding free energy calculations for six antimicrobial peptide–micelle systems, three peptides interacting with two types of micelles. The peptides are the scorpion derived antimicrobial peptide (AMP), IsCT and two of its analogues. The micelles are dodecylphosphatidylcholine (DPC) and sodium dodecylsulphate (SDS) micelles. The interfacial electrostatic properties of DPC and SDS micelles are assumed to be similar to those of zwitterionic mammalian and anionic bacterial mem...

  9. 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 ...

  10. 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 ...

  11. 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.

  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. Perspectives on the evolutionary ecology of arthropod antimicrobial peptides.

    Science.gov (United States)

    Rolff, Jens; Schmid-Hempel, Paul

    2016-05-26

    Antimicrobial peptides (AMPs) are important elements of the innate immune defence in multicellular organisms that target and kill microbes. Here, we reflect on the various points that are raised by the authors of the 11 contributions to a special issue of Philosophical Transactions on the 'evolutionary ecology of arthropod antimicrobial peptides'. We see five interesting topics emerging. (i) AMP genes in insects, and perhaps in arthropods more generally, evolve much slower than most other immune genes. One explanation refers to the constraints set by AMPs being part of a finely tuned defence system. A new view argues that AMPs are under strong stabilizing selection. Regardless, this striking observation still invites many more questions than have been answered so far. (ii) AMPs almost always are expressed in combinations and sometimes show expression patterns that are dependent on the infectious agent. While it is often assumed that this can be explained by synergistic interactions, such interactions have rarely been demonstrated and need to be studied further. Moreover, how to define synergy in the first place remains difficult and needs to be addressed. (iii) AMPs play a very important role in mediating the interaction between a host and its mutualistic or commensal microbes. This has only been studied in a very small number of (insect) species. It has become clear that the very same AMPs play different roles in different situations and hence are under concurrent selection. (iv) Different environments shape the physiology of organisms; especially the host-associated microbial communities should impact on the evolution host AMPs. Studies in social insects and some organisms from extreme environments seem to support this notion, but, overall, the evidence for adaptation of AMPs to a given environment is scant. (v) AMPs are considered or already developed as new drugs in medicine. However, bacteria can evolve resistance to AMPs. Therefore, in the light of our

  14. 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

  15. 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.

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. 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

  19. 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.

  20. The proteome targets of intracellular targeting antimicrobial peptides.

    Science.gov (United States)

    Shah, Pramod; Hsiao, Felix Shih-Hsiang; Ho, Yu-Hsuan; Chen, Chien-Sheng

    2016-04-01

    Antimicrobial peptides have been considered well-deserving candidates to fight the battle against microorganisms due to their broad-spectrum antimicrobial activities. Several studies have suggested that membrane disruption is the basic mechanism of AMPs that leads to killing or inhibiting microorganisms. Also, AMPs have been reported to interact with macromolecules inside the microbial cells such as nucleic acids (DNA/RNA), protein synthesis, essential enzymes, membrane septum formation and cell wall synthesis. Proteins are associated with many intracellular mechanisms of cells, thus protein targets may be specifically involved in mechanisms of action of AMPs. AMPs like pyrrhocoricin, drosocin, apidecin and Bac 7 are documented to have protein targets, DnaK and GroEL. Moreover, the intracellular targeting AMPs are reported to influence more than one protein targets inside the cell, suggesting for the multiple modes of actions. This complex mechanism of intracellular targeting AMPs makes them more difficult for the development of resistance. Herein, we have summarized the current status of AMPs in terms of their mode of actions, entry to cytoplasm and inhibition of macromolecules. To reveal the mechanism of action, we have focused on AMPs with intracellular protein targets. We have also included the use of high-throughput proteome microarray to determine the unidentified AMP protein targets in this review. PMID:26648572

  1. Relative free energy of binding between antimicrobial peptides and SDS or DPC micelles.

    Science.gov (United States)

    Sayyed-Ahmad, Abdallah; Khandelia, Himanshu; Kaznessis, Yiannis N

    2009-09-01

    We present relative binding free energy calculations for six antimicrobial peptide-micelle systems, three peptides interacting with two types of micelles. The peptides are the scorpion derived antimicrobial peptide (AMP), IsCT and two of its analogues. The micelles are dodecylphosphatidylcholine (DPC) and sodium dodecylsulphate (SDS) micelles. The interfacial electrostatic properties of DPC and SDS micelles are assumed to be similar to those of zwitterionic mammalian and anionic bacterial membrane interfaces, respectively. We test the hypothesis that the binding strength between peptides and the anionic micelle SDS can provide information on peptide antimicrobial activity, since it is widely accepted that AMPs function by binding to and disrupting the predominantly anionic lipid bilayer of the bacterial cytoplasmic membrane. We also test the hypothesis that the binding strength between peptides and the zwitterionic micelle DPC can provide information on peptide haemolytic activities, since it is accepted that they also bind to and disrupt the zwitterionic membrane of mammalian cells. Equilibrium structures of the peptides, micelles and peptide-micelle complexes are obtained from more than 300 ns of molecular dynamics simulations. A thermodynamic cycle is introduced to compute the binding free energy from electrostatic, non-electrostatic and entropic contributions. We find relative binding free energy strengths between peptides and SDS to correlate with the experimentally measured rankings for peptide antimicrobial activities, and relative free energy binding strengths between peptides and DPC to correlate with the observed rankings for peptide haemolytic toxicities. These findings point to the importance of peptide-membrane binding strength for antimicrobial activity and haemolytic activity. PMID:21113423

  2. Immune Signaling and Antimicrobial Peptide Expression in Lepidoptera

    Directory of Open Access Journals (Sweden)

    Heidi Goodrich-Blair

    2013-07-01

    Full Text Available Many lepidopteran insects are agricultural pests that affect stored grains, food and fiber crops. These insects have negative ecological and economic impacts since they lower crop yield, and pesticides are expensive and can have off-target effects on beneficial arthropods. A better understanding of lepidopteran immunity will aid in identifying new targets for the development of specific insect pest management compounds. A fundamental aspect of immunity, and therefore a logical target for control, is the induction of antimicrobial peptide (AMP expression. These peptides insert into and disrupt microbial membranes, thereby promoting pathogen clearance and insect survival. Pathways leading to AMP expression have been extensively studied in the dipteran Drosophila melanogaster. However, Diptera are an important group of pollinators and pest management strategies that target their immune systems is not recommended. Recent advances have facilitated investigation of lepidopteran immunity, revealing both conserved and derived characteristics. Although the general pathways leading to AMP expression are conserved, specific components of these pathways, such as recognition proteins have diverged. In this review we highlight how such comparative immunology could aid in developing pest management strategies that are specific to agricultural insect pests.

  3. 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...

  4. 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...

  5. 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...

  6. 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...

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

    OpenAIRE

    Bobek Libuse A; Campagna Alexander N; Wei Guo-Xian

    2007-01-01

    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-...

  8. Antimicrobial peptides from skin secretions of Chinese red belly toad Bombina maxima.

    Science.gov (United States)

    Lai, Ren; Zheng, Yong Tang; Shen, Ji Hong; Liu, Guan Jie; Liu, Hen; Lee, Wen Hui; Tang, Shao Zhong; Zhang, Yun

    2002-03-01

    Two groups of antimicrobial peptides have been isolated from skin secretions of Bombina maxima. Peptides in the first group, named maximins 1, 2, 3, 4 and 5, are structurally related to bombinin-like peptides (BLPs). Unlike BLPs, sequence variations in maximins occurred all through the molecules. In addition to the potent antimicrobial activity, cytotoxicity against tumor cells and spermicidal action of maximins, maximin 3 possessed a significant anti-HIV activity. Maximins 1 and 3 were toxic to mice with LD(50) values of 8.2 and 4.3 mg/kg, respectively. Peptides in the second group, termed maximins H1, H2, H3 and H4, are homologous with bombinin H peptides. cDNA sequences revealed that one maximin peptide plus one maximin H peptide derived from a common larger protein. PMID:11835991

  9. 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

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

    Science.gov (United States)

    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

  11. 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.

  12. 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.

  13. 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

  14. Mechanisms and consequences of bacterial resistance to antimicrobial peptides.

    Science.gov (United States)

    Andersson, D I; Hughes, D; Kubicek-Sutherland, J Z

    2016-05-01

    Cationic antimicrobial peptides (AMPs) are an intrinsic part of the human innate immune system. Over 100 different human AMPs are known to exhibit broad-spectrum antibacterial activity. Because of the increased frequency of resistance to conventional antibiotics there is an interest in developing AMPs as an alternative antibacterial therapy. Several cationic peptides that are derivatives of AMPs from the human innate immune system are currently in clinical development. There are also ongoing clinical studies aimed at modulating the expression of AMPs to boost the human innate immune response. In this review we discuss the potential problems associated with these therapeutic approaches. There is considerable experimental data describing mechanisms by which bacteria can develop resistance to AMPs. As for any type of drug resistance, the rate by which AMP resistance would emerge and spread in a population of bacteria in a natural setting will be determined by a complex interplay of several different factors, including the mutation supply rate, the fitness of the resistant mutant at different AMP concentrations, and the strength of the selective pressure. Several studies have already shown that AMP-resistant bacterial mutants display broad cross-resistance to a variety of AMPs with different structures and modes of action. Therefore, routine clinical administration of AMPs to treat bacterial infections may select for resistant bacterial pathogens capable of better evading the innate immune system. The ramifications of therapeutic levels of exposure on the development of AMP resistance and bacterial pathogenesis are not yet understood. This is something that needs to be carefully studied and monitored if AMPs are used in clinical settings. PMID:27180309

  15. Toward Infection-Resistant Surfaces: Achieving High Antimicrobial Peptide Potency by Modulating the Functionality of Polymer Brush and Peptide.

    Science.gov (United States)

    Yu, Kai; Lo, Joey C Y; Mei, Yan; Haney, Evan F; Siren, Erika; Kalathottukaren, Manu Thomas; Hancock, Robert E W; Lange, Dirk; Kizhakkedathu, Jayachandran N

    2015-12-30

    Bacterial infection associated with indwelling medical devices and implants is a major clinical issue, and the prevention or treatment of such infections is challenging. Antimicrobial coatings offer a significant step toward addressing this important clinical problem. Antimicrobial coatings based on tethered antimicrobial peptides (AMPs) on hydrophilic polymer brushes have been shown to be one of the most promising strategies to avoid bacterial colonization and have demonstrated broad spectrum activity. Optimal combinations of the functionality of the polymer-brush-tethered AMPs are essential to maintaining long-term AMP activity on the surface. However, there is limited knowledge currently available on this topic. Here we report the development of potent antimicrobial coatings on implant surfaces by elucidating the roles of polymer brush chemistry and peptide structure on the overall antimicrobial activity of the coatings. We screened several combinations of polymer brush coatings and AMPs constructed on nanoparticles, titanium surfaces, and quartz slides on their antimicrobial activity and bacterial adhesion against Gram-positive and Gram-negative bacteria. Highly efficient killing of planktonic bacteria by the antimicrobial coatings on nanoparticle surfaces, as well as potent killing of adhered bacteria in the case of coatings on titanium surfaces, was observed. Remarkably, the antimicrobial activity of AMP-conjugated brush coatings demonstrated a clear dependence on the polymer brush chemistry and peptide structure, and optimization of these parameters is critical to achieving infection-resistant surfaces. By analyzing the interaction of polymer-brush-tethered AMPs with model lipid membranes using circular dichroism spectroscopy, we determined that the polymer brush chemistry has an influence on the extent of secondary structure change of tethered peptides before and after interaction with biomembranes. The peptide structure also has an influence on the density

  16. Reactive Oxygen Species, Apoptosis, Antimicrobial Peptides and Human Inflammatory Diseases

    Directory of Open Access Journals (Sweden)

    Babatunji Emmanuel Oyinloye

    2015-04-01

    Full Text Available Excessive free radical generation, especially reactive oxygen species (ROS leading to oxidative stress in the biological system, has been implicated in the pathogenesis and pathological conditions associated with diverse human inflammatory diseases (HIDs. Although inflammation which is considered advantageous is a defensive mechanism in response to xenobiotics and foreign pathogen; as a result of cellular damage arising from oxidative stress, if uncontrolled, it may degenerate to chronic inflammation when the ROS levels exceed the antioxidant capacity. Therefore, in the normal resolution of inflammatory reactions, apoptosis is acknowledged to play a crucial role, while on the other hand, dysregulation in the induction of apoptosis by enhanced ROS production could also result in excessive apoptosis identified in the pathogenesis of HIDs. Apparently, a careful balance must be maintained in this complex environment. Antimicrobial peptides (AMPs have been proposed in this review as an excellent candidate capable of playing prominent roles in maintaining this balance. Consequently, in novel drug design for the treatment and management of HIDs, AMPs are promising candidates owing to their size and multidimensional properties as well as their wide spectrum of activities and indications of reduced rate of resistance.

  17. Antimicrobial peptide genes in Bacillus strains from plant environments.

    Science.gov (United States)

    Mora, Isabel; Cabrefiga, Jordi; Montesinos, Emilio

    2011-12-01

    The presence of the antimicrobial peptide (AMP) biosynthetic genes srfAA (surfactin), bacA (bacylisin), fenD (fengycin), bmyB (bacyllomicin), spaS (subtilin), and ituC (iturin) was examined in 184 isolates of Bacillus spp. obtained from plant environments (aerial, rhizosphere, soil) in the Mediterranean land area of Spain. Most strains had between two and four AMP genes whereas strains with five genes were seldom detected and none of the strains had six genes. The most frequent AMP gene markers were srfAA, bacA, bmyB, and fenD, and the most frequent genotypes srfAA-bacA-bmyB and srfAAbacA- bmyB-fenD. The dominance of these particular genes in Bacillus strains associated with plants reinforces the competitive role of surfactin, bacyllomicin, fengycin, and bacilysin in the fitness of strains in natural environments. The use of these AMP gene markers may assist in the selection of putative biological control agents of plant pathogens. PMID:22569759

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

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    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.

  19. 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

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

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    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.

  1. 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...

  2. Biosynthesis of the Polycyclic Antimicrobial Peptides Lacticin 481, Haloduracin, and Cinnamycin

    Science.gov (United States)

    Cooper, Lisa E.

    2009-01-01

    Lantibiotics are bacterial-derived polycyclic antimicrobial peptides. They are genetically encoded and ribosomally synthesized as precursor peptides containing a structural region that undergoes post-translational modification and a leader sequence that is not modified. Specific serine and threonine residues in the pre-lantibiotic structural…

  3. Structural study of a novel antimicrobial peptide isolated from the venom of bee Anthophora plumipes

    Czech Academy of Sciences Publication Activity Database

    Čujová, Sabína; Veverka, Václav; Buděšínský, Miloš; Bednárová, Lucie; Čeřovský, Václav

    2014-01-01

    Roč. 20, Suppl S1 (2014), S263-S264. ISSN 1075-2617. [European Peptide Symposium /33./. 31.08.2014-05.09.2014, Sofia] Institutional support: RVO:61388963 Keywords : antimicrobial peptide s * membranes * CD-spectroscopy * NMR spectroscopy Subject RIV: CC - Organic Chemistry

  4. Contribution of Amphipathicity and Hydrophobicity to the Antimicrobial Activity and Cytotoxicity of β-Hairpin Peptides

    Science.gov (United States)

    2016-01-01

    Bacteria have acquired extensive resistance mechanisms to protect themselves against antibiotic action. Today the bacterial membrane has become one of the “final frontiers” in the search for new compounds acting on novel targets to address the threat of multi-drug resistant (MDR) and XDR bacterial pathogens. β-Hairpin antimicrobial peptides are amphipathic, membrane-binding antibiotics that exhibit a broad range of activities against Gram-positive, Gram-negative, and fungal pathogens. However, most members of the class also possess adverse cytotoxicity and hemolytic activity that preclude their development as candidate antimicrobials. We examined peptide hydrophobicity, amphipathicity, and structure to better dissect and understand the correlation between antimicrobial activity and toxicity, membrane binding, and membrane permeability. The hydrophobicity, pI, net charge at physiological pH, and amphipathic moment for the β-hairpin antimicrobial peptides tachyplesin-1, polyphemusin-1, protegrin-1, gomesin, arenicin-3, and thanatin were determined and correlated with key antimicrobial activity and toxicity data. These included antimicrobial activity against five key bacterial pathogens and two fungi, cytotoxicity against human cell lines, and hemolytic activity in human erythrocytes. Observed antimicrobial activity trends correlated with compound amphipathicity and, to a lesser extent, with overall hydrophobicity. Antimicrobial activity increased with amphipathicity, but unfortunately so did toxicity. Of note, tachyplesin-1 was found to be 8-fold more amphipathic than gomesin. These analyses identify tachyplesin-1 as a promising scaffold for rational design and synthetic optimization toward an antibiotic candidate.

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

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    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.

  6. Antitumor Activity of Antimicrobial Peptides Containing CisoDGRC in CD13 Negative Breast Cancer Cells

    OpenAIRE

    Hou, Lei; ZHAO, XINHAN; Wang, Pei; Ning, Qian; Meng, Min; Liu, Caigang

    2013-01-01

    Backgroud isoAsp-Gly-Arg (isoDGR) is a derivative of the Asn-Gly-Arg (NGR) motif, which is used as a targeted delivery tool to aminopeptidase N (CD13) positive cells. Recent studies have shown that cyclic isoDGR (CisoDGRC) has a more efficient affinity with αvβ3, a type of integrin that overexpresses in tumor cells. Antimicrobial peptides (AMPs) are an efficient antitumor peptide that specifically kills tumor cells. In the present study, we designed antimicrobial peptides containing the CisoD...

  7. 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

    high plectasin encapsulation efficiency (71-90%) and mediated release of the peptide over 24h. The antimicrobial efficacy of the peptide-loaded nanoparticles was investigated using bronchiolar epithelial Calu-3 cell monolayers infected with S. aureus. The plectasin-loaded nanoparticles displayed......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...

  8. Purification and Characterization of a New Antimicrobial Peptide from Skin Secretions of Bufo Kavirensis

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    H Zare Zardini

    2014-04-01

    Results: A novel antimicrobial peptide was obtained from skin secretions. This peptide is composed of 20 amino acids. This peptide does not present any similarity with the other antimicrobial peptides from the amphibians. Thus, it was named Maximin Bk. The peptide was subjected to antimicrobial activity assays. The Buforin–Kpeptide showed considerable antimicrobial activity against Gram positive and Gram negative bacteria (minimum inhibitory concentrations (MIC, 8.1 to 20.78 µg/ml as well as fungi (MIC, 25.7 to 35.6 mg/ml. Moreover, this peptide showed higher antimicrobial activity against Gram-negative than against Gram-positive bacteria and fungi. Maximin Bk showed virtually low hemolytic activity, which, at a concentration of 100 μg/mL, induced 5% hemolysis. Thus, a very slight haemolytic activity was obtained against human erythrocytes. Conclusion: On the basis of the biological effects, Buforin–Kcan can be regarded as the potent agent for treatment of various microbial diseases.

  9. Candida species and antimicrobial peptides from the venom of different wild bees

    Czech Academy of Sciences Publication Activity Database

    Slaninová, Jiřina; Borovičková, Lenka; Putnová, H.; Monincová, Lenka; Fučík, Vladimír; Čeřovský, Václav

    Praha : Institut of organic Chemistry and Biochemistry ASCR, 2009 - (Slaninová, J.), s. 113-117 ISBN 978-80-86241-31-9. - (Collection Symposium Series. 11). [Biologically Active Peptides. Conference /11./. Praha (CZ), 22.04.2009-24.04.2009] R&D Projects: GA ČR GA203/03/1362 Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptides * alpha-helical amphipathic peptides * Candida species * fungicidal activity Subject RIV: CC - Organic Chemistry

  10. 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. PMID:20640445

  11. 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

  12. 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.

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

    Science.gov (United States)

    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

  14. Maximins S, a novel group of antimicrobial peptides from toad Bombina maxima.

    Science.gov (United States)

    Wang, Ting; Zhang, Jie; Shen, Ji-Hong; Jin, Yang; Lee, Wen-Hui; Zhang, Yun

    2005-02-18

    Amphibian skin secretions are rich in antimicrobial peptides acting as important components of innate defense system against invading microorganisms. A novel type of peptide, designated as maximin S, was deduced by random sequencing of 793 clones from a constructed Bombina maxima skin cDNA library. The putative primary structures of maximin S peptides can be grouped into five species, in which maximin S1 has 14 amino acid residues and the rest of maximin S peptides (S2-S5) all have 18 amino acid residues. Unlike most of the amphibian antimicrobial peptides so far identified, the newly characterized four maximin S precursors are composed of maximin S1 and different combinations of tandem repeated maximin S2-S5 linked by internal peptides. Except maximin S1, the predicted secondary structures of maximin S2-S5 show a similar amphipathic alpha-helical structure. MALDI-TOF mass spectrometry analysis of partially isolated skin secretions of the toad indicates that most of the deduced maximin S peptides are expressed. Two deduced maximin S peptides (S1, S4) were synthesized and their antimicrobial activities were tested. Maximin S4 only had an antibiotic activity against mycoplasma and had no antibacterial or antifungal activity toward tested strains. Maximin S1 had no activity under the same conditions. PMID:15649437

  15. 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.

  16. Variety of antimicrobial peptides in the Bombina maxima toad and evidence of their rapid diversification.

    Science.gov (United States)

    Lee, Wen-Hui; Li, Yan; Lai, Ren; Li, Sha; Zhang, Yun; Wang, Wen

    2005-04-01

    Antimicrobial peptides secreted by the skin of many amphibians play an important role in innate immunity. From two skin cDNA libraries of two individuals of the Chinese red belly toad (Bombina maxima), we identified 56 different antimicrobial peptide cDNA sequences, each of which encodes a precursor peptide that can give rise to two kinds of antimicrobial peptides, maximin and maximin H. Among these cDNA, we found that the mean number of nucleotide substitution per non-synonymous site in both the maximin and maximin H domains significantly exceed the mean number of nucleotide substitution per synonymous site, whereas the same pattern was not observed in other structural regions, such as the signal and propiece peptide regions, suggesting that these antimicrobial peptide genes have been experiencing rapid diversification driven by Darwinian selection. We cloned and sequenced seven genes amplified from skin or liver genomic DNA. These genes have three exons and share the same gene structure, in which both maximin and maximin H are encoded by the third exon. This suggests that alternative splicing and somatic recombination are less likely to play a role in creating the diversity of maximins and maximin Hs. The gene trees based on different domain regions revealed that domain shuffling or gene conversion among these genes might have happened frequently. PMID:15770703

  17. Characterization of a highly potent antimicrobial peptide microcin N from uropathogenic Escherichia coli.

    Science.gov (United States)

    Kaur, Kamaljit; Tarassova, Oxana; Dangeti, Ramana Venkata; Azmi, Sarfuddin; Wishart, David; McMullen, Lynn; Stiles, Michael

    2016-06-01

    Microcin N is a low-molecular weight, highly active antimicrobial peptide produced by uropathogenic Escherichia coli In this study, the native peptide was expressed and purified from pGOB18 plasmid carrying E. coli in low yield. The pure peptide was characterized using mass spectrometry, N-terminal sequencing by Edman degradation as well as trypsin digestion. We found that the peptide is 74-residue long, cationic (+2 total charge), highly hydrophobic and consists of glycine as the first N-terminal residue. The minimum inhibitory concentration of the peptide against Salmonella enteritidis was found to be 150 nM. Evaluation of the solution conformation of the peptide using circular dichroism spectroscopy showed that the peptide is well folded in 40% trifluoroethanol with helical structure whereas the folded structure is lost in aqueous solution. To increase the yield of this potent peptide, we overexpressed GST-tagged microcin N using E. coli BL21. Recombinant GST-tagged microcin N was successfully expressed in E. coli BL21; however, the cleaved mature microcin N did not show activity against the indicator strain (S. enterica) most likely due to the extreme hydrophobic nature of the peptide. Efforts to produce active microcin N in large scale are discussed as this peptide has huge potential to be the next generation antimicrobial agent. PMID:27190283

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

    Directory of Open Access Journals (Sweden)

    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.

  19. 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

  20. 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

  1. Induced Bacterial Cross-Resistance toward Host Antimicrobial Peptides: A Worrying Phenomenon

    OpenAIRE

    Fleitas, Osmel; Franco, Octávio L.

    2016-01-01

    Bacterial resistance to conventional antibiotics has reached alarming levels, threatening to return to the pre-antibiotic era. Therefore, the search for new antimicrobial compounds that overcome the resistance phenomenon has become a priority. Antimicrobial peptides (AMPs) appear as one of the most promising antibiotic medicines. However, in recent years several AMP-resistance mechanisms have been described. Moreover, the AMP-resistance phenomenon has become more complex due to its associatio...

  2. Inducible Resistance of Fish Bacterial Pathogens to the Antimicrobial Peptide Cecropin B▿

    OpenAIRE

    Sallum, Ulysses W.; Chen, Thomas T

    2008-01-01

    Cecropin B is a cationic antimicrobial peptide originally isolated from the diapausing pupae of the giant silk moth, Hylphora cecropia. Cecropin B elicits its antimicrobial effects through disruption of the anionic cell membranes of gram-negative bacteria. Previous work by our laboratory demonstrated that a constitutively expressed cecropin B transgene conferred enhanced resistance to bacterial infection in medaka. The development of antibiotic resistance by pathogenic bacteria is a growing p...

  3. 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

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

    International Nuclear Information System (INIS)

    Highlights: ► New kyotorphin derivatives have antimicrobial properties against S. aureus. ► Atomic force microscopy show membrane disturbing effects of KTP–NH2 and IbKTP–NH2. ► None of the KTP derivatives are hemolytic. ► 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–NH2, IbKTP, IbKTP–NH2 – 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 and broadens the therapeutic potential and application of kyotorphin peptides.

  5. 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.

  6. 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

  7. Neutron Repulsion

    CERN Document Server

    Manuel, Oliver K

    2011-01-01

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding...

  8. The SMART model: Soft Membranes Adapt and Respond, also Transiently, in the presence of antimicrobial peptides.

    Science.gov (United States)

    Bechinger, Burkhard

    2015-05-01

    Biophysical and structural studies of peptide-lipid interactions, peptide topology and dynamics have changed our view on how antimicrobial peptides insert and interact with membranes. Clearly, both the peptides and the lipids are highly dynamic, change and mutually adapt their conformation, membrane penetration and detailed morphology on a local and a global level. As a consequence, the peptides and lipids can form a wide variety of supramolecular assemblies in which the more hydrophobic sequences preferentially, but not exclusively, adopt transmembrane alignments and have the potential to form oligomeric structures similar to those suggested by the transmembrane helical bundle model. In contrast, charged amphipathic sequences tend to stay intercalated at the membrane interface where they cause pronounced disruptions of the phospholipid fatty acyl packing. At increasing local or global concentrations, the peptides result in transient membrane openings, rupture and ultimately lysis. Depending on peptide-to-lipid ratio, lipid composition and environmental factors (temperature, buffer composition, ionic strength, etc.), the same peptide sequence can result in a variety of those responses. Therefore, the SMART model has been introduced to cover the full range of possibilities. With such a view in mind, novel antimicrobial compounds have been designed from amphipathic polymers, peptide mimetics, combinations of ultra-short polypeptides with hydrophobic anchors or small designer molecules. PMID:25522713

  9. 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

  10. Maximin 9, a novel free thiol containing antimicrobial peptide with antimycoplasma activity from frog Bombina maxima.

    Science.gov (United States)

    Lee, Wen-Hui; Zhang, Jie; Zhang, Ying-Xia; Jin, Yang; Lai, Ren; Zhang, Yun

    2005-08-15

    Amphibian skin is a rich resource of antimicrobial peptides, like maximins and maximin Hs from frog Bombina maxima. Novel cDNA clones encoding a precursor protein, which comprises a novel maximin peptide (maximin 9) and reported maximin H3, were isolated from two constructed skin cDNA libraries of B. maxima. The predicted primary structure of maximin 9 is GIGRKFLGGVKTTFRCGVKDFASKHLY-NH2. A surprising substitution is at position 16, with a free cysteine in maximin 9 rather than usual conserved glycine in other reported maximins. Maximin 9, the homodimer form and its Cys16 to Gly16 mutant were synthesized and their antimicrobial activities were evaluated. Unlike previously reported maximin 3, the tested bacterial and fungal strains were resistant to maximin 9, its homodimer and the Cys16 to Gly16 mutant (with MICs>100 microM). On the other hand, interestingly, while eight clinical Mollicutes strains were generally resistant to maximin 9 homodimer and its Cys16 to Gly16 mutant, most of them are sensitive to maximin 9 at a peptide concentration of 30 microM, especially in the presence of dithiothreitol. These results indicate that the presence of a reactive Cys residue in maximin 9 is important for its antimycoplasma activity. The diversity of antimicrobial peptide cDNA structures encountered in B. maxima skin cDNA libraries and the antimicrobial specificity differences of the peptides may reflect well the species' adaptation to the unique microbial environments. PMID:16061233

  11. 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

  12. Activity of antimicrobial peptides from the venom of hymenoptera against Candida albicans biofilms

    Czech Academy of Sciences Publication Activity Database

    Putnová, Helena; Fučík, Vladimír; Monincová, Lenka; Čeřovský, Václav; Slaninová, Jiřina

    Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 107-110 ISBN 978-80-86241-44-9. - (Collection Symposium Series. 13). [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] R&D Projects: GA ČR GA203/08/0536 Institutional research plan: CEZ:AV0Z40550506 Keywords : biofilm * antifungal activity * antimicrobial peptides * XTT assay Subject RIV: CC - Organic Chemistry

  13. 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....

  14. Secretion and activity of antimicrobial peptide cecropin D expressed in Pichia pastoris

    OpenAIRE

    Guo, Chunhe; Huang, Yumao; Zheng, Hongyu; TANG, LIYUN; He, Jun; XIANG, LINSHENG; LIU, DEHUI; JIANG, HOUQUAN

    2012-01-01

    To express the antimicrobial peptide cecropin D in Pichia pastoris and determine the activity of the expressed product, four oligonucleotide fragments were synthesized in accordance with the available cecropin D sequences and a codon bias suitable for Pichia pastoris. Sequence fragments were phosphorylated, annealed, linked and cloned into the expression vector pGAPZαA and the yeast α-mating factor signal peptide was used as the signal sequence. The P. pastoris SMD1168 cells were transformed ...

  15. Lasiocepsin, a novel cyclic antimicrobial peptide from the venom of eusocial bee Lasioglossum laticeps (Hymenoptera: Halictidae)

    Czech Academy of Sciences Publication Activity Database

    Monincová, Lenka; Slaninová, Jiřina; Fučík, Vladimír; Hovorka, Oldřich; Voburka, Zdeněk; Bednárová, Lucie; Maloň, Petr; Štokrová, Jitka; Čeřovský, Václav

    2012-01-01

    Roč. 43, č. 2 (2012), s. 751-761. ISSN 0939-4451 R&D Projects: GA ČR GA203/08/0536; GA ČR GAP205/10/1276 Grant ostatní: GAUK(CZ) 33779266 Keywords : antimicrobial peptides * disulfide bridge * analogs * peptide synthesis * wild-bee venom * CD spectroscopy Subject RIV: CE - Biochemistry Impact factor: 3.914, year: 2012

  16. 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.

  17. 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.

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

    Science.gov (United States)

    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

  19. 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

  20. 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

  1. 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

  2. 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...

  3. Extracellular DNA-induced antimicrobial peptide resistance mechanisms in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    ShawnLewenza

    2013-02-01

    Full Text Available Extracellular DNA (eDNA is in the environment, bodily fluids, in the matrix of biofilms, and accumulates at infection sites. Extracellular DNA can function as a nutrient source, a universal biofilm matrix component and an innate immune effector in extracellular DNA traps. In biofilms, eDNA is required for attachment, aggregation and stabilization of microcolonies. We have recently shown that eDNA can sequester divalent metal cations, which has interesting implications on antibiotic resistance. Extracellular DNA binds metal cations and thus activates the Mg2+-responsive PhoPQ and PmrAB two-component systems. In Pseudomonas aeruginosa and many other Gram-negative bacteria, the PhoPQ/PmrAB systems control various genes required for virulence and resisting killing by antimicrobial peptides, including the pmr genes (PA3552-PA3559 that are responsible for the addition of aminoarabinose to lipid A. The PA4773-PA4775 genes are a second DNA-induced cluster and are required for the production of spermidine on the outer surface, which protects the outer membrane from antimicrobial peptide treatment. Both modifications mask the negative surface charges and limit membrane damage by antimicrobial peptides. DNA-enriched biofilms or planktonic cultures have increased antibiotic resistance phenotypes to antimicrobial peptides and aminoglycosides. These dual antibiotic resistance and immune evasion strategies may be expressed in DNA-rich environments and contribute to long-term survival.

  4. Multitasking antimicrobial peptides, plant development, and host defense against biotic/abiotic stress

    Science.gov (United States)

    Crop losses due to pathogens are a major threat to global food security. Plants employ a multilayer defense system against pathogens including use of physical barriers (cell wall), induction of hypersensitive defense response (HR), resistance (R) proteins, and synthesis of antimicrobial peptides (AM...

  5. 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

    We report long time scale simulations of the 18-residue helical antimicrobial peptide ovispirin-1 and its analogs novispirin-G10 and novispirin-T7 in SDS micelles. The SDS micelle serves as an economical and effective model for a cellular membrane. Ovispirin, which is initially placed along a mic...

  6. Panurgines, novel antimicrobial peptides from the venom of communal bee Panurgus calcaratus (Hymenoptera: Andrenidae)

    Czech Academy of Sciences Publication Activity Database

    Čujová, Sabína; Slaninová, Jiřina; Monincová, Lenka; Fučík, Vladimír; Bednárová, Lucie; Štokrová, Jitka; Hovorka, Oldřich; Voburka, Zdeněk; Straka, J.; Čeřovský, Václav

    2013-01-01

    Roč. 45, č. 1 (2013), s. 143-157. ISSN 0939-4451 R&D Projects: GA ČR GA203/08/0536 Institutional support: RVO:61388963 Keywords : antimicrobial peptides * wild bee venom * CD spectroscopy * large unilamellar vesicles * electron microscopy Subject RIV: CE - Biochemistry Impact factor: 3.653, year: 2013

  7. Chiroptical properties of the antimicrobial peptide Lasiocepsin and of its analogs

    Czech Academy of Sciences Publication Activity Database

    Baumruk, V.; Pazderková, Markéta; Maloň, P.; Profant, V.; Bednárová, Lucie

    Bochum : Ruhr-University Bochum, 2015. s. 87-88. [European Conference on the Spectroscopy of Biological Molecules /16./. 06.09.2015-10.09.2015, Bochum] Institutional support: RVO:61388963 Keywords : antimicrobial peptide * lasiocepsin * vibrational optical activity * circular dichroism * simulation Subject RIV: CF - Physical ; Theoretical Chemistry

  8. 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

  9. Larvae of flesh fly Neobellieria bullata as a source for novel antimicrobial peptides

    Czech Academy of Sciences Publication Activity Database

    Neubauerová, Tereza; Macková, Martina; Macek, Tomáš; Šanda, Miloslav; Voburka, Zdeněk

    Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 100-102 ISBN 978-80-86241-44-9. - (Collection Symposium Series. 13). [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] Grant ostatní: GA ČR(CZ) GA522/09/1693; GA ČR(CZ) GD305/09/H008 Institutional research plan: CEZ:AV0Z40550506 Keywords : peptide synthesis * Neobellieria bullata * antimicrobial peptide Subject RIV: CC - Organic Chemistry

  10. 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

  11. Structure and antimicrobial activity of platypus 'intermediate' defensin-like peptide.

    Science.gov (United States)

    Torres, Allan M; Bansal, Paramjit; Koh, Jennifer M S; Pagès, Guilhem; Wu, Ming J; Kuchel, Philip W

    2014-05-01

    The three-dimensional structure of a chemically synthesized peptide that we have called 'intermediate' defensin-like peptide (Int-DLP), from the platypus genome, was determined by nuclear magnetic resonance (NMR) spectroscopy; and its antimicrobial activity was investigated. The overall structural fold of Int-DLP was similar to that of the DLPs and β-defensins, however the presence of a third antiparallel β-strand makes its structure more similar to the β-defensins than the DLPs. Int-DLP displayed potent antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. The four arginine residues at the N-terminus of Int-DLP did not affect the overall fold, but were important for its antimicrobial potency. PMID:24694388

  12. 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

  13. 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...... residues 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...

  14. 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

  15. 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).

  16. 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)

  17. 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.

  18. 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)

  19. Membrane interactions of mesoporous silica nanoparticles as carriers of antimicrobial peptides.

    Science.gov (United States)

    Braun, Katharina; Pochert, Alexander; Lindén, Mika; Davoudi, Mina; Schmidtchen, Artur; Nordström, Randi; Malmsten, Martin

    2016-08-01

    Membrane interactions are critical for the successful use of mesoporous silica nanoparticles as delivery systems for antimicrobial peptides (AMPs). In order to elucidate these, we here investigate effects of nanoparticle charge and porosity on AMP loading and release, as well as consequences of this for membrane interactions and antimicrobial effects. Anionic mesoporous silica particles were found to incorporate considerable amounts of the cationic AMP LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES (LL-37), whereas loading is much lower for non-porous or positively charged silica nanoparticles. Due to preferential pore localization, anionic mesoporous particles, but not the other particles, protect LL-37 from degradation by infection-related proteases. For anionic mesoporous nanoparticles, membrane disruption is mediated almost exclusively by peptide release. In contrast, non-porous silica particles build up a resilient LL-37 surface coating due to their higher negative surface charge, and display largely particle-mediated membrane interactions and antimicrobial effects. For positively charged mesoporous silica nanoparticles, LL-37 incorporation promotes the membrane binding and disruption displayed by the particles in the absence of peptide, but also causes toxicity against human erythrocytes. Thus, the use of mesoporous silica nanoparticles as AMP delivery systems requires consideration of membrane interactions and selectivity of both free peptide and the peptide-loaded nanoparticles, the latter critically dependent on nanoparticle properties. PMID:27174622

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

    Energy Technology Data Exchange (ETDEWEB)

    Bai Liqiang [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Park, Hangzhou 310018 (China); Zhu Liangjun; Min Sijia [College of Animal Sciences, Zhejiang University, Hangzhou 310029 (China); Liu Lin; Cai Yurong [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Park, Hangzhou 310018 (China); Yao Juming [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Park, Hangzhou 310018 (China)], E-mail: yaoj@zstu.edu.cn

    2008-03-15

    The Bombyx mori silk fibroin films (SFFs) were modified by a Cecropin B (CB) antimicrobial peptide, (NH{sub 2})-NGIVKAGPAIAVLGEAAL-CONH{sub 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)

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. Development of an anti-microbial peptide-mediated liposomal delivery system: a novel approach towards pH-responsive anti-microbial peptides.

    Science.gov (United States)

    Zhang, Qianyu; Tang, Jie; Ran, Rui; Liu, Yayuan; Zhang, Zhirong; Gao, Huile; He, Qin

    2016-05-01

    On one hand, the application of anti-microbial peptides (AMPs) in the construction of AMPs-mediated drug delivery system has not yet been fully exploited; on the other hand, its non-selectivity in vivo has also limited its clinical application. In this work, we chose one pH-responsive peptide, [D]-H6L9, and functionalized it onto the surface of liposomes (D-Lip). The protonation of histidines in the sequence of [D]-H6L9 under pH 6.3 could switch the surface charge of D-Lip from negative (under pH 7.4) to positive (under pH 6.3), and the cellular uptake and tumor spheroids uptake were increased accordingly. Lysosome co-localization assay suggested that there was only little overlap of D-Lip with lysosomes in 12 h, which indicated that D-Lip could escape lysosomes effectively. In vivo biodistribution assay on C26 tumor-bearing BALB/C mice showed that DiR-labeled D-Lip could reach tumors as much as PEG-Lip, and both tumor slices and quantitative measurement of dispersed cells of in vivo tumors by flow cytometry demonstrated that D-Lip could be taken up by tumors more efficiently. Therefore, we have established an anti-microbial peptide-mediated liposomal delivery system for tumor delivery. PMID:25693639

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

    International Nuclear Information System (INIS)

    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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Antimicrobial peptide, hdMolluscidin, purified from the gill of the abalone, Haliotis discus.

    Science.gov (United States)

    Seo, Jung-Kil; Go, Hye-Jin; Kim, Chan-Hee; Nam, Bo-Hye; Park, Nam Gyu

    2016-05-01

    A 4.7 kDa antimicrobial peptide was purified from the acidified gill extract of the Abalone, Haliotis discus, by cation-exchange and C18 reversed-phase high performance liquid chromatography (HPLC). Comparison of the amino acid sequences and molecular weight of this peptide with those of other known antimicrobial peptides revealed that this antimicrobial peptide have high sequence homology with that of cgMolluscidin and was designated hdMolluscidin. hdMolluscidin is composed of 46 amino acid residues containing several dibasic residue repeats like KK or K-R. hdMolluscidin showed potent antimicrobial activity against both Gram-positive bacteria including Bacillus subtilis and Staphylococcus aureus (minimal effective concentrations [MECs]; 0.8-19.0 μg/mL) and Gram-negative bacteria including Aeromonas hydrophila, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Shigella flexneri, and Vibrio parahemolyticus ([MECs]; 1.0-4.0 μg/mL) without hemolytic activity. However, hdMolluscidin did not show any significant activity against Candida albicans. The secondary structural prediction suggested that hdMolluscidin might not form an ordered or an amphipathic structure. hdMolluscidin did not show membrane permeabilization or leakage ability. The full-length hdMolluscidin cDNA contained 566-bp, including a 5'-untranslated region (UTR) of 63-bp, a 3'-UTR of 359-bp, and an open reading frame of 144-bp encoding 47 amino acids (containing Met). cDNA study of hdMolluscidin suggests that it is expressed as a mature peptide. Our results indicate that hdMolluscidin could relate to the innate immune defenses in abalone and it may not act directly on bacterial membrane. PMID:27033467

  13. 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...

  14. 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

    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 in...

  15. Coqui frogs persist with the deadly chytrid fungus despite a lack of defensive antimicrobial peptides.

    Science.gov (United States)

    Rollins-Smith, Louise A; Reinert, Laura K; Burrowes, Patricia A

    2015-02-10

    The amphibian skin fungus Batrachochytrium dendrobatidis (Bd) occurs widely in Puerto Rico and is thought to be responsible for the apparent extinction of 3 species of endemic frogs in the genus Eleutherodactylus, known as coquis. To examine immune defenses which may protect surviving species, we induced secretion of skin peptides from adult common coqui frogs E. coqui collected from upland forests at El Yunque. By matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, we were unable to detect peptide signals suggestive of antimicrobial peptides, and enriched peptides showed no capacity to inhibit growth of Bd. Thus, it appears that E. coqui depend on other skin defenses to survive in the presence of this deadly fungus. PMID:25667340

  16. 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...

  17. Ribonuclease 7, an antimicrobial peptide up-regulated during infection, contributes to microbial defense of the human urinary tract

    OpenAIRE

    Spencer, John David; Schwaderer, Andrew L.; Wang, Huanyu; Bartz, Julianne; Kline, Jennifer; Eichler, Tad; DeSouza, Kristin R.; Sims-Lucas, Sunder; Baker, Peter; Hains, David S.

    2013-01-01

    The mechanisms that maintain sterility in the urinary tract are incompletely understood; however, recent studies stress the importance of antimicrobial peptides in protecting the urinary tract from infection. Ribonuclease 7 (RNase 7), a potent antimicrobial peptide contributing to urinary tract sterility, is expressed by intercalated cells in the renal collecting tubules and is present in the urine at levels sufficient to kill bacteria at baseline. Here, we characterize the expression and fun...

  18. 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 ...

  19. Larvae of flesh fly Neobellieria bullata as a source for novel antimicrobial peptides

    Czech Academy of Sciences Publication Activity Database

    Neubauerová, Tereza; Macková, M.; Macek, Tomáš; Šanda, Miloslav; Voburka, Zdeněk

    Praha : Ústav organické chemie a biochemie AV ČR, v.v.i, 2011 - (Slaninová, J.; Borovičková, L.). s. 49-49 ISBN 978-80-86241-36-4. [Biologically Active Peptides /12./. 27.04.2011-29.04.2011, Praha] R&D Projects: GA ČR GD305/09/H008 Grant ostatní: GA ČR(CZ) GA522/09/1693 Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptides * Neobellieria bullata Subject RIV: CC - Organic Chemistry

  20. Activity of antimicrobial peptides from the venom of Hymenoptera against Candida albicans biofilms

    Czech Academy of Sciences Publication Activity Database

    Putnová, Helena; Fučík, Vladimír; Monincová, Lenka; Čeřovský, Václav; Slaninová, Jiřina

    Praha : Ústav organické chemie a biochemie AV ČR, v.v.i, 2011 - (Slaninová, J.; Borovičková, L.). s. 53-53 ISBN 978-80-86241-36-4. [Biologically Active Peptides /12./. 27.04.2011-29.04.2011, Praha] R&D Projects: GA ČR GA203/08/0536 Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptides * Candida albicans * biofilms * insect Subject RIV: CC - Organic Chemistry

  1. Reducing Escherichia coli growth on a composite biomaterial by a surface immobilized antimicrobial peptide.

    Science.gov (United States)

    Buckholtz, Gavin A; Reger, Nina A; Anderton, William D; Schimoler, Patrick J; Roudebush, Shana L; Meng, Wilson S; Miller, Mark C; Gawalt, Ellen S

    2016-08-01

    A new composite bioceramic consisting of calcium aluminum oxide (CaAlO) and hydroxyapatite (HA) was functionalized with the synthetic antimicrobial peptide Inverso-CysHHC10. CaAlO is a bioceramic that can be mold cast easily and quickly at room temperature. Improved functionality was previously achieved through surface reactions. Here, composites containing 0-5% HA (by mass) were prepared and the elastic modulus and modulus of rupture were mechanically similar to non-load bearing bone. The addition of hydroxyapatite resulted in increased osteoblast attachment (>180%) and proliferation (>140%) on all composites compared to 100% CaAlO. Antimicrobial peptide (AMP) immobilization was achieved using an interfacial alkene-thiol click reaction. The linked AMP persisted on the composite (>99.6% after 24h) and retained its activity against Escherichia coli based on N-phenylnaphthylamine uptake and bacterial turbidity tests. Overall, this simple scaffold system improves osteoblast activity and reduces bacterial activity. PMID:27157735

  2. 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

  3. 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...

  4. 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...

  5. One step at a time: Action mechanism of Sushi 1 antimicrobial peptide and derived molecules

    OpenAIRE

    Leptihn, Sebastian; Guo, Lin; Frecer, Vladimir; Ho, Bow; Ding, Jeak Ling; Wohland, Thorsten

    2010-01-01

    Antimicrobial peptides (AMPs) are a crucial part of the innate immune system of eukaryotes and present a possible alternative to common antibiotics. It is therefore of great importance to understand their modes of action. Using a single-molecule approach in combination with high resolution imaging and biofunctional assays we were able to determine the different steps occurring during the action of the α-helical AMP Sushi 1 during bacterial lysis in spatial and temporal resolution in a biologi...

  6. 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...

  7. 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...

  8. Toll-like receptor and antimicrobial peptide expression in the bovine endometrium

    Directory of Open Access Journals (Sweden)

    Conlan R Steven

    2008-11-01

    Full Text Available Abstract Background The endometrium is commonly infected with bacteria leading to severe disease of the uterus in cattle and humans. The endometrial epithelium is the first line of defence for this mucosal surface against bacteria and Toll-like receptors (TLRs are a critical component of the innate immune system for detection of pathogen associated molecular patterns (PAMPs. Antimicrobial peptides, acute phase proteins and Mucin-1 (MUC-1 also provide non-specific defences against microbes on mucosal surfaces. The present study examined the expression of innate immune defences in the bovine endometrium and tested the hypothesis that endometrial epithelial cells express functional receptors of the TLR family and the non-specific effector molecules for defence against bacteria. Methods Bovine endometrial tissue and purified populations of primary epithelial and stromal cells were examined using RT-PCR for gene expression of TLRs, antimicrobial peptides and MUC-1. Functional responses were tested by evaluating the secretion of prostaglandin E2 and acute phase proteins when cells were treated with bacterial PAMPs such as bacterial lipopolysaccharide (LPS and lipoproteins. Results The endometrium expressed TLRs 1 to 10, whilst purified populations of epithelial cells expressed TLRs 1 to 7 and 9, and stromal cells expressed TLRs 1 to 4, 6, 7, 9 and 10. The TLRs appear to be functional as epithelial cells secreted prostaglandin E2 in response to bacterial PAMPs. In addition, the epithelial cells expressed antimicrobial peptides, such as Tracheal and Lingual Antimicrobial Peptides (TAP and LAP and MUC-1, which were upregulated when the cells were treated with LPS. However, the epithelial cells did not express appreciable amounts of the acute phase proteins haptoglobin or serum amyloid A. Conclusion Epithelial cells have an essential role in the orchestration of innate immune defence of the bovine endometrium and are likely to be the key to prevention of

  9. Chiroptical spectroscopy as a sensitive tool for the conformational analysis of antimicrobial peptides

    Czech Academy of Sciences Publication Activity Database

    Kocourková, L.; Novotná, P.; Čujová, Sabína; Čeřovský, Václav; Urbanová, M.; Setnička, V.

    Prague : Charles University in Prague, Faculty of Science, 2015 - (Nesměrák, K.), s. 67-73 ISBN 978-80-7444-036-6. [International Students Conference "Modern Analytical Chemistry " /11./. Prague (CZ), 22.09.2015-23.09.2015] R&D Projects: GA ČR GAP208/11/0105 Institutional support: RVO:61388963 Keywords : antimicrobial peptides * circular dichroism * conformation * liposomes * model membranes Subject RIV: CB - Analytical Chemistry , Separation

  10. Variation in Streptococcus pneumoniae susceptibility to human antimicrobial peptides may mediate intraspecific competition

    OpenAIRE

    Habets, Michelle G. J. L.; Rozen, Daniel E; Brockhurst, Michael A

    2012-01-01

    Streptococcus pneumoniae is a facultative pathogen inhabiting the nasopharynx of humans where it is exposed to a range of antimicrobial peptides (AMPs) of the innate immune response. It is possible therefore that the susceptibility of strains to AMPs plays a role in determining their ability to colonize, and furthermore, that AMPs could mediate competitive interactions between co-colonizing genotypes. However, little is known about patterns of natural variation in AMP susceptibility of S. pne...

  11. Separation and structure-mobility relationship study of cyclic antimicrobial peptides by capillary zone electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav

    Helsinki: -, 2015. YS5. [International Symposium on Electro- and Liquid Phase-Separation Techniques (ITP2015) /22./ and Nordic Separation Science Symposium (NoSSS2015) /8./. 30.08.2015-03.09.2015, Helsinki] R&D Projects: GA ČR(CZ) GA15-01948S Institutional support: RVO:61388963 Keywords : structure-mobility relationship * antimicrobial peptides * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation

  12. 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...

  13. A Novel Immune Evasion Strategy of Candida albicans: Proteolytic Cleavage of a Salivary Antimicrobial Peptide

    OpenAIRE

    Meiller, Timothy F.; Hube, Bernhard; Schild, Lydia; Shirtliff, Mark E.; Mark A. Scheper; Winkler, Robert; Ton, Amy; Jabra-Rizk, Mary Ann

    2009-01-01

    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 ...

  14. 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...

  15. 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...

  16. Curcumin induces human cathelicidin antimicrobial peptide gene expression through a vitamin D receptor-independent pathway

    OpenAIRE

    Guo, Chunxiao; Rosoha, Elena; Lowry, Malcolm B.; Borregaard, Niels; Gombart, Adrian F.

    2012-01-01

    The vitamin D receptor (VDR) mediates the pleiotropic biologic effects of 1α,25 dihydroxy-vitamin D3. Recent in vitro studies suggested that curcumin and poly-unsaturated fatty acids (PUFAs) also bind to VDR with low affinity. As potential ligands for the VDR, we hypothesized that curcumin and PUFAs would induce expression of known VDR target genes in cells. In this study, we tested whether these compounds regulated two important VDR target genes - human cathelicidin antimicrobial peptide (CA...

  17. Comparing Selection on S. aureus between Antimicrobial Peptides and Common Antibiotics

    OpenAIRE

    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 ag...

  18. 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

  19. 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

  20. Alarin but not its alternative-splicing form, GALP (Galanin-like peptide) has antimicrobial activity

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Akihiro, E-mail: a-wada@nagasaki-u.ac.jp [Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan); Wong, Pooi-Fong [Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Hojo, Hironobu [Department of Applied Biochemistry, Institute of Glycoscience, Tokai University, Kanagawa 2591292 (Japan); Hasegawa, Makoto [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Shiga 5260829 (Japan); Ichinose, Akitoyo [Electron Microscopy Shop Central Laboratory, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan); Llanes, Rafael [Institute Pedro Kouri, Havana (Cuba); Kubo, Yoshinao [Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 8528523 (Japan); Senba, Masachika [Department of Pathology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan); Ichinose, Yoshio [Kenya Research Station, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523 (Japan)

    2013-05-03

    Highlights: • Alarin inhibits the growth of E. coli but not S. aureus. • Alarin’s potency is comparable to LL-37 in inhibiting the growth of E. coli. • Alarin can cause bacterial membrane blebbing. • Alalin does not induce hemolysis on erythrocytes. -- Abstract: Alarin is an alternative-splicing form of GALP (galanin-like peptide). It shares only 5 conserved amino acids at the N-terminal region with GALP which is involved in a diverse range of normal brain functions. This study seeks to investigate whether alarin has additional functions due to its differences from GALP. Here, we have shown using a radial diffusion assay that alarin but not GALP inhibited the growth of Escherichia coli (strain ML-35). The conserved N-terminal region, however, remained essential for the antimicrobial activity of alarin as truncated peptides showed reduced killing effect. Moreover, alarin inhibited the growth of E. coli in a similar potency as human cathelicidin LL-37, a well-studied antimicrobial peptide. Electron microscopy further showed that alarin induced bacterial membrane blebbing but unlike LL-37, it did not cause hemolysis of erythrocytes. In addition, alarin is only active against the gram-negative bacteria, E. coli but not the gram-positive bacteria, Staphylococcus aureus. Thus, these data suggest that alarin has potentials as an antimicrobial and should be considered for the development in human therapeutics.

  1. Antimicrobial peptide-like genes in Nasonia vitripennis: a genomic perspective

    Directory of Open Access Journals (Sweden)

    Zhu Shunyi

    2010-03-01

    Full Text Available Abstract Background Antimicrobial peptides (AMPs are an essential component of innate immunity which can rapidly respond to diverse microbial pathogens. Insects, as a rich source of AMPs, attract great attention of scientists in both understanding of the basic biology of the immune system and searching molecular templates for anti-infective drug design. Despite a large number of AMPs have been identified from different insect species, little information in terms of these peptides is available from parasitic insects. Results By using integrated computational approaches to systemically mining the Hymenopteran parasitic wasp Nasonia vitripennis genome, we establish the first AMP repertoire whose members exhibit extensive sequence and structural diversity and can be distinguished into multiple molecular types, including insect and fungal defensin-like peptides (DLPs with the cysteine-stabilized α-helical and β-sheet (CSαβ fold; Pro- or Gly-rich abaecins and hymenoptaecins; horseshoe crab tachystatin-type AMPs with the inhibitor cystine knot (ICK fold; and a linear α-helical peptide. Inducible expression pattern of seven N. vitripennis AMP genes were verified, and two representative peptides were synthesized and functionally identified to be antibacterial. In comparison with Apis mellifera (Hymenoptera and several non-Hymenopteran model insects, N. vitripennis has evolved a complex antimicrobial immune system with more genes and larger protein precursors. Three classical strategies that are likely responsible for the complexity increase have been recognized: 1 Gene duplication; 2 Exon duplication; and 3 Exon-shuffling. Conclusion The present study established the N. vitripennis peptidome associated with antimicrobial immunity by using a combined computational and experimental strategy. As the first AMP repertoire of a parasitic wasp, our results offer a basic platform for further studying the immunological and evolutionary significances of these

  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. High in vitro antimicrobial activity of β-peptoid-peptide hybrid oligomers against planktonic and biofilm cultures of Staphylococcus epidermidis

    DEFF Research Database (Denmark)

    Liu, Yang; Knapp, Kolja Michael; Yang, Liang;

    2013-01-01

    An array of β-peptoid-peptide hybrid oligomers displaying different amino acid/peptoid compositions and chain lengths was studied with respect to antimicrobial activity against Staphylococcus epidermidis both in planktonic and biofilm cultures, comparing the effects with those of the common antib...... killing of bacterial cells. This class of peptidomimetics may constitute promising antimicrobial alternatives for the prevention and treatment of multidrug-resistant S. epidermidis infections.......An array of β-peptoid-peptide hybrid oligomers displaying different amino acid/peptoid compositions and chain lengths was studied with respect to antimicrobial activity against Staphylococcus epidermidis both in planktonic and biofilm cultures, comparing the effects with those of the common...

  4. Strategies and molecular tools to fight antimicrobial resistance: resistome, transcriptome and antimicrobial peptides

    OpenAIRE

    MarceloDe OliveiraSantos

    2013-01-01

    The increasing number of antibiotic resistant bacteria motivates prospective research towards discovery of new antimicrobial active substances. There are, however, controversies concerning the cost-effectiveness of such research with regards to the description of new substances with novel cellular interactions, or description of new uses of existing substances to overcome resistance. Although examination of bacteria isolated from remote locations with limited exposure to humans has revealed a...

  5. 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.

  6. 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

  7. Effect of hydrocarbon stapling on the properties of alpha-helical antimicrobial peptides isolated from the venom of hymenoptera

    Czech Academy of Sciences Publication Activity Database

    Chapuis, Hubert Jean; Slaninová, Jiřina; Bednárová, Lucie; Monincová, Lenka; Buděšínský, Miloš; Čeřovský, Václav

    2012-01-01

    Roč. 43, č. 5 (2012), s. 2047-2058. ISSN 0939-4451 R&D Projects: GA ČR GA203/08/0536 Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptides * stapled peptides * amphipathic helix * CD spectroscopy Subject RIV: CC - Organic Chemistry Impact factor: 3.914, year: 2012

  8. Characterization of the Antimicrobial Peptide Penisin, a Class Ia Novel Lantibiotic from Paenibacillus sp. Strain A3.

    Science.gov (United States)

    Baindara, Piyush; Chaudhry, Vasvi; Mittal, Garima; Liao, Luciano M; Matos, Carolina O; Khatri, Neeraj; Franco, Octavio L; Patil, Prabhu B; Korpole, Suresh

    2016-01-01

    Attempts to isolate novel antimicrobial peptides from microbial sources have been on the rise recently, despite their low efficacy in therapeutic applications. Here, we report identification and characterization of a new efficient antimicrobial peptide from a bacterial strain designated A3 that exhibited highest identity with Paenibacillus ehimensis. Upon purification and subsequent molecular characterization of the antimicrobial peptide, referred to as penisin, we found the peptide to be a bacteriocin-like peptide. Consistent with these results, RAST analysis of the entire genome sequence revealed the presence of a lantibiotic gene cluster containing genes necessary for synthesis and maturation of a lantibiotic. While circular dichroism and one-dimension nuclear magnetic resonance experiments confirmed a random coil structure of the peptide, similar to other known lantibiotics, additional biochemical evidence suggests posttranslational modifications of the core peptide yield six thioether cross-links. The deduced amino acid sequence of the putative biosynthetic gene penA showed approximately 74% similarity with elgicin A and 50% similarity with the lantibiotic paenicidin A. Penisin effectively killed methicillin-resistant Staphylococcus aureus (MRSA) and did not exhibit hemolysis activity. Unlike other lantibiotics, it effectively inhibited the growth of Gram-negative bacteria. Furthermore, 80 mg/kg of body weight of penisin significantly reduced bacterial burden in a mouse thigh infection model and protected BALB/c mice in a bacteremia model entailing infection with Staphylococcus aureus MTCC 96, suggesting that it could be a promising new antimicrobial peptide. PMID:26574006

  9. Novel Peptides from Skins of Amphibians Showed Broad-Spectrum Antimicrobial Activities.

    Science.gov (United States)

    Wang, Ying; Zhang, Yue; Lee, Wen-Hui; Yang, Xinwang; Zhang, Yun

    2016-03-01

    Peptide agents are often considered as potential biomaterials for developing new drugs that can overcome the rising resistance of pathogenic micro-organisms to classic antibiotic treatments. One key source of peptide agents is amphibian skin, as they provide a great deal of naturally occurring antimicrobial peptide (AMP) templates awaiting further exploitation and utilization. In this study, 12 novel AMPs from the skins of 3 ranid frogs, Rana limnocharis, R. exilispinosa, and Amolops afghanus, were identified using a 5' PCR primer. A total of 11 AMPs exhibited similarities with currently known AMP families, including brevinin-1, brevinin-2, esculentin-1, and nigrocin, besides, one AMP, named as Limnochariin, represented a novel AMP family. All 12 AMPs contain a C-terminus cyclic motif and most of them show obvious antimicrobial activities against 18 standard and clinically isolated strains of bacteria, including 4 Gram-positive bacteria, 11 Gram-negative bacteria, and 3 fungus. These findings provide helpful insight that will be useful in the design of anti-infective peptide agents. PMID:26452973

  10. 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

  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. 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....... 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 in...... the micellar core and the polar side chains protruding into the aqueous phase. There is overwhelming evidence that points to the significant and indispensable participation of hydrophobic residues in binding to the zwitterionic interface. The simulation starts with a conformation that is unbiased...

  13. 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......), calcein dye leakage and fluorescence spectroscopy. OCD consistently showed that Nc is bound in an alpha-helical, surface bound state over a range of peptide to lipid (P/L) ratios up to approximately 1:15. Realignment of Nc at higher P/L ratios correlates to loss of membrane integrity as shown by Laurdan...... 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...

  14. Understanding the adsorption of salmon calcitonin, antimicrobial peptide AP114 and polymyxin B onto lipid nanocapsules.

    Science.gov (United States)

    Umerska, Anita; Matougui, Nada; Groo, Anne-Claire; Saulnier, Patrick

    2016-06-15

    The adsorption of therapeutic molecules, e.g., peptides, onto nanocarriers is influenced by the properties of the carrier, adsorbed molecule and continuous phase. Hence, through changes in the composition of the nanocarrier and the medium, it should be possible to tune the system to make it capable of efficiently adsorbing peptides. The adsorption of calcitonin, antimicrobial peptide AP114 and polymyxin B onto lipid nanocapsules was investigated. The adsorption data were fitted to a Langmuir isotherm. Dynamic light scattering and laser Doppler velocimetry were used to investigate the changes in the hydrodynamic diameter and zeta potential, respectively, of the nanocarrier. The peptide adsorption was primarily governed by electrostatic forces; however, even without the presence of an ionisable surfactant, a significant amount of each tested molecule was adsorbed due to the enormous surface area of the nanocarriers and to peptide-nanocarrier interactions. The addition of an ionisable lipophilic surfactant, lecithin, improved the adsorption yield, which reached values of up to 100%. The adsorption yield and the properties of the nanocarrier, particularly the zeta potential, depended on the carrier and peptide concentrations and their mixing ratio. The adsorption of all tested molecules obeyed the Langmuir model over a limited concentration range. PMID:27113868

  15. Multiple peptide resistance factor (MprF)-mediated Resistance of Staphylococcus aureus against antimicrobial peptides coincides with a modulated peptide interaction with artificial membranes comprising lysyl-phosphatidylglycerol.

    Science.gov (United States)

    Andrä, Jörg; Goldmann, Torsten; Ernst, Christoph M; Peschel, Andreas; Gutsmann, Thomas

    2011-05-27

    Modification of the membrane lipid phosphatidylglycerol (PG) of Staphylococcus aureus by enzymatic transfer of a l-lysine residue leading to lysyl-PG converts the net charge of PG from -1 to +1 and is thought to confer resistance to cationic antimicrobial peptides (AMPs). Lysyl-PG synthesis and translocation to the outer leaflet of the bacterial membrane are achieved by the membrane protein MprF. Consequently, mutants lacking a functional mprF gene are in particular vulnerable to the action of AMPs. Hence, we aim at elucidating whether and to which extent lysyl-PG modulates membrane binding, insertion, and permeabilization by various AMPs. Lysyl-PG was incorporated into artificial lipid bilayers, mimicking the cytoplasmic membrane of S. aureus. Moreover, we determined the activity of the peptides against a clinical isolate of S. aureus strain SA113 and two mutants lacking a functional mprF gene and visualized peptide-induced ultrastructural changes of bacteria by transmission electron microscopy. The studied peptides were: (i) NK-2, an α-helical fragment of mammalian NK-lysin, (ii) arenicin-1, a lugworm β-sheet peptide, and (iii) bee venom melittin. Biophysical data obtained by FRET spectroscopy, Fourier transform infrared spectroscopy, and electrical measurements with planar lipid bilayers were correlated with the biological activities of the peptides. They strongly support the hypothesis that peptide-membrane interactions are a prerequisite for eradication of S. aureus. However, degree and mode of modulation of membrane properties such as fluidity, capacitance, and conductivity were unique for each of the peptides. Altogether, our data support and underline the significance of lysyl-PG for S. aureus resistance to AMPs. PMID:21474443

  16. 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

  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. 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. PMID:22489028

  19. Technetium-99m labelled antimicrobial peptides discriminate between bacterial infections and sterile inflammations

    International Nuclear Information System (INIS)

    The aim of this study was to select technetium-99m labelled peptides that can discriminate between bacterial infections and sterile inflammations. For this purpose, we first assessed the binding of various 99mTc-labelled natural or synthetic peptides, which are based on the sequence of the human antimicrobial peptide ubiquicidin (UBI) or human lactoferrin (hLF), to bacteria and to leucocytes in vitro. In order to select peptides that preferentially bind to bacteria over host cells, radiolabelled peptides were injected into mice intraperitoneally infected with Klebsiella pneumoniae (K. pneumoniae) and the amount of radioactivity associated with the bacteria and with the leucocytes was quantitated. The next phase focussed on discrimination between bacterial infections and sterile inflammatory processes using 99mTc-labelled peptides in mice intramuscularly infected with various bacteria (e.g. multi-drug-resistant Staphylococcus aureus) and in animals that had been injected with lipopolysaccharides (LPS) of bacterial origin to create a sterile inflammatory process. Also, we studied the distribution of 99mTc-labelled UBI 29-41 and UBI 18-35 in rabbits having an experimental thigh muscle infection with K. pneumoniae and in rabbits injected with LPS. Based on the results of our in vitro and in vivo binding assays, two peptides, i.e. UBI 29-41 and UBI 18-35, were selected as possible candidates for infection imaging. The radiolabelled peptides can detect infections with both gram-positive and gram-negative bacteria in mice as early as 5-30 min after injection, with a target-to-non-target (T/NT) ratio between 2 and 3; maximum T/NT ratios were seen within 1 h after injection. In rabbits, high T/NT ratios (>5) for 99mTc-labelled UBI 29-41 were observed from 1 h after injection. No accumulation of the selected 99mTc-labelled UBI-derived peptides was observed in thighs of mice and rabbits previously injected with LPS. Scintigraphic investigation into the biodistribution of 99m

  20. 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.

  1. 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

  2. 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

  3. 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

  4. Position-Dependent Influence of the Three Trp Residues on the Membrane Activity of the Antimicrobial Peptide, Tritrpticin

    Directory of Open Access Journals (Sweden)

    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.

  5. 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. PMID:26208148

  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. Characterisation of three alpha-helical antimicrobial peptides from the venom of Scorpio maurus palmatus.

    Science.gov (United States)

    Harrison, Patrick L; Abdel-Rahman, Mohamed A; Strong, Peter N; Tawfik, Mohamed M; Miller, Keith

    2016-07-01

    Scorpion venoms provide a rich source of anti-microbial peptides. Here we characterise three from the venom of Scorpion maurus palmatus. Smp13 is biologically inactive, despite sharing homology with other antimicrobial peptides, probably because it lacks a typically charged structure. Both Smp-24 and Smp-43 have broad spectrum antimicrobial activity, disrupting bacterial membranes. In addition, there is evidence that Smp24 may inhibit DNA synthesis in Bacillus subtilis. Smp24 haemolysed red blood cells but in contrast, Smp43 was non-haemolytic. The introduction of a flexible Gly-Val-Gly hinge into the middle of Smp24 did not alter the haemolytic activity of Smp24 (as might have been predicted from earlier studies with Pandinin2 (Pin2), although C-terminal truncation of Smp-24 reduced its haemolytic activity, in agreement with earlier Pin 2 studies. Smp24 and its derivatives, as well as Smp-43, were all cytotoxic (ATP release assay) toward mammalian HepG2 liver cells. Our results highlight the beneficial effect of helical-hinge-helical conformation on promoting prokaryotic selectivity of long chain scorpion AMPs, as well as the importance of examining a wide range of mammalian cell types in cytotoxicity testing. PMID:27019370

  8. Characterization of Cimex lectularius (bedbug) defensin peptide and its antimicrobial activity against human skin microflora.

    Science.gov (United States)

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

    2016-02-19

    Antimicrobial peptides are components of both vertebrate and invertebrate innate immune systems that are expressed in response to exposure to bacterial antigens. Naturally occurring antimicrobial peptides from evolutionarily ancient species have been extensively studied and are being developed as potential therapeutics against antibiotic resistant microorganisms. In this study, a putative Cimex lectularius (bedbug, CL) defensin is characterized for its effectiveness against human skin flora including Gram-negative and Gram-positive bacteria. The bedbug defensin (CL-defensin), belonging to family of insect defensins, is predicted to have a characteristic N-terminal loop, an α-helix, and an antiparallel β-sheet, which was supported by circular dichroism spectroscopy. The defensin was shown to be antimicrobial against Gram-positive bacteria commonly found on human skin (Micrococcus luteus, Corynebacterium renale, Staphylococcus aureus and Staphylococcus epidermidis); however, it was ineffective against common skin Gram-negative bacteria (Pseudomonas aeruginosa and Acinetobacter baumannii) under low-salt conditions. CL-defensin was also effective against M. luteus and C. renale in high-salt (MIC) conditions. Our studies indicate that CL-defensin functions by depolarization and pore-formation in the bacterial cytoplasmic membrane. PMID:26802465

  9. Expression of essential genes for biosynthesis of antimicrobial peptides of Bacillus is modulated by inactivated cells of target microorganisms.

    Science.gov (United States)

    Leães, Fernanda Leal; Velho, Renata Voltolini; Caldas, Danielle Gregório Gomes; Ritter, Ana Carolina; Tsai, Siu Mui; Brandelli, Adriano

    2016-01-01

    Certain Bacillus strains are important producers of antimicrobial peptides with great potential for biological control. Antimicrobial peptide production by Bacillus amyloliquefaciens P11 was investigated in the presence of heat-inactivated cells of bacteria and fungi. B. amyloliquefaciens P11 exhibited higher antimicrobial activity in the presence of inactivated cells of Staphylococcus aureus and Aspergillus parasiticus compared to other conditions tested. Expression of essential genes related to biosynthesis of the antimicrobial peptides surfactin (sfp), iturin A (lpa-14 and ituD), subtilosin A (sboA) and fengycin (fenA) was investigated by quantitative real-time PCR (qRT-PCR). The genes lpa-14 and ituD were highly expressed in the presence of S. aureus (inactivated cells), indicating induction of iturin A production by B. amyloliquefaciens P11. The other inducing condition (inactivated cells of A. parasiticus) suppressed expression of lpa-14, but increased expression of ituD. A twofold increase in fenA expression was observed for both conditions, while strong suppression of sboA expression was observed in the presence of inactivated cells of S. aureus. An increase in antimicrobial activity was observed, indicating that synthesis of antimicrobial peptides may be induced by target microorganisms. PMID:26577655

  10. β-Boomerang Antimicrobial and Antiendotoxic Peptides: Lipidation and Disulfide Bond Effects on Activity and Structure

    Directory of Open Access Journals (Sweden)

    Harini Mohanram

    2014-04-01

    Full Text Available Drug-resistant Gram-negative bacterial pathogens and endotoxin- or lipopolysaccharide (LPS-mediated inflammations are among some of the most  prominent health issues globally. Antimicrobial peptides (AMPs are eminent molecules that can kill drug-resistant strains and neutralize LPS toxicity. LPS, the outer layer of the outer membrane of Gram-negative bacteria safeguards cell integrity against hydrophobic compounds, including antibiotics and AMPs. Apart from maintaining structural integrity, LPS, when released into the blood stream, also induces inflammatory pathways leading to septic shock. In previous works, we have reported the de novo design of a set of 12-amino acid long cationic/hydrophobic peptides for LPS binding and activity. These peptides adopt β-boomerang like conformations in complex with LPS. Structure-activity studies demonstrated some critical features of the β-boomerang scaffold that may be utilized for the further development of potent analogs. In this work, β-boomerang lipopeptides were designed and structure-activity correlation studies were carried out. These lipopeptides were homo-dimerized through a disulfide bridge to stabilize conformations and for improved activity. The designed peptides exhibited potent antibacterial activity and efficiently neutralized LPS toxicity under in vitro assays. NMR structure of C4YI13C in aqueous solution demonstrated the conserved folding of the lipopeptide with a boomerang aromatic lock stabilized with disulfide bond at the C-terminus and acylation at the N-terminus. These lipo-peptides displaying bacterial sterilization and low hemolytic activity may be useful for future applications as antimicrobial and antiendotoxin molecules.

  11. An antimicrobial peptide Ar-AMP from amaranth (Amaranthus retroflexus L.) seeds.

    Science.gov (United States)

    Lipkin, Aleksey; Anisimova, Veronika; Nikonorova, Aleksandra; Babakov, Aleksey; Krause, Eberhardt; Bienert, Mikhael; Grishin, Eugene; Egorov, Tsezi

    2005-10-01

    A 30-residue antimicrobial peptide Ar-AMP was isolated from the seeds of amaranth Amaranthus retroflexus L. essentially by a single step procedure using reversed-phase HPLC, and its in vitro biological activities were studied. The complete amino acid sequence of Ar-AMP was determined by Edman degradation in combination with mass spectrometric methods. In addition, the cDNA encoding Ar-AMP was obtained and sequenced. The cDNA encodes a precursor protein consisting of the N-terminal putative signal sequence of 25 amino acids, a mature peptide of 30 amino acids and a 34-residue long C-terminal region cleaved during post-translational processing. According to sequence similarity the Ar-AMP belongs to the hevein-like family of antimicrobial peptides with six cysteine residues. In spite of the fact that seeds were collected in 1967 and lost their germination capacity, Ar-AMP retained its biological activities. It effectively inhibited the growth of different fungi tested: Fusarium culmorium (Smith) Sacc., Helminthosporium sativum Pammel., King et Bakke, Alternaria consortiale Fr., and Botrytis cinerea Pers., caused morphological changes in Rhizoctonia solani Kühn at micromolar concentrations and protected barley seedlings from H. sativum infection. PMID:16126239

  12. 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.

  13. 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.

  14. 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

  15. Multiple Functions of the New Cytokine-Based Antimicrobial Peptide Thymic Stromal Lymphopoietin (TSLP

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    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.

  16. Structure-Function Relationships of Antimicrobial Peptides and Proteins with Respect to Contact Molecules on Pathogen Surfaces.

    Science.gov (United States)

    Zhang, Ruiyan; Eckert, Thomas; Lutteke, Thomas; Hanstein, Stefan; Scheidig, Axel; Bonvin, Alexandre M J J; Nifantiev, Nikolay E; Kozar, Tibor; Schauer, Roland; Enani, Mushira Abdulaziz; Siebert, Hans-Christian

    2016-01-01

    The Antimicrobial peptides (e.g. defensins, hevein-like molecules and food-protecting peptides like nisin) are able to interact specifically with contact structures on pathogen surfaces. Besides protein receptors, important recognition points for such contacts are provided by pathogen glycan chains or surface lipids. Therefore, structural data concerning surface exposed glycans and lipids are of the highest clinical interest since these recognition functions play a key role when optimising anti-infection therapies. Approaches in nanomedicine and nanopharmacology in which various biophysical techniques such as NMR (Nuclear Magnetic Resonance), AFM (Atomic Force Microscopy), SPR (Surface Plasmon Resonance) and X-ray crystallography can be combined with biochemical and cell-biological methods will lead to improved antimicrobial peptides by this rational drug design approach. Such a strategy is extremely well suited to support clinical studies focussing on an effective fight against multiresistant pathogens. The data sets which are described here can be considered as universal for the design of various antimicrobial drugs against certain pathogens (bacteria, viruses and fungi) which cause severe diseases in humans and animals. Furthermore, these insights are also helpful for progressing developments in the field of food conservation and food preservation. A detailed analysis of the structure-function relationships between antimicrobial peptides and contact molecules on pathogen surfaces at the sub-molecular level will lead to a higher degree of specificity of antimicrobial peptides. PMID:26139116

  17. 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...

  18. Research advances of antimicrobial peptides and applications in food industry and agriculture.

    Science.gov (United States)

    Meng, Shuo; Xu, Huanli; Wang, Fengshan

    2010-06-01

    Antimicrobial peptides (AMPs) are produced by a wide range of organisms and serve as their natural defenses against infection caused by bacteria, viruses and fungi. Because of the positively charge and amphipathic structure, AMPs kill target cells through diverse and complex mechanisms once in a target membrane and these special mechanisms are considered to be the critical factors for the less tendency of drug resistance development. Thus AMPs may become a new generation of promising antimicrobial agents in future anti-infection application. Additionally, AMPs can also be used in food industry and agriculture. On the basis of discussing the structural features, action mechanisms and sources, the applications of AMPs were reviewed in this paper, including in food industry, feedstuff, cultivation of disease-resistant transgenic plant, cultivation of transgenic animal, and aquaculture, especially the patented applications. PMID:20408795

  19. 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

  20. 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...

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

    DEFF Research Database (Denmark)

    Hansen, Anna Mette; Bonke, Gitte; Larsen, Camilla Josephine; Yavari, Niloofar; Nielsen, Peter E.; Franzyk, Henrik

    2016-01-01

    )-Tat48-60, BF-2A-RXR, and drosocin-RXR are capable of transporting PNA effectively into E. coli (MICs of 1-4 μM). Importantly, presence of the inner-membrane peptide transporter SbmA was not required for antibacterial activity of PNA-AMP conjugates containing Pep-1-K, KLW-9,13-a, or drosocin-RXR (MICs...

  2. Antimicrobial peptides and nitric oxide production by neutrophils from periodontitis subjects

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    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.

  3. Mercury-Supported Biomimetic Membranes for the Investigation of Antimicrobial Peptides

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    Lucia Becucci

    2014-01-01

    Full Text Available Tethered bilayer lipid membranes (tBLMs consist of a lipid bilayer interposed between an aqueous solution and a hydrophilic “spacer” anchored to a gold or mercury electrode. There is great potential for application of these biomimetic membranes for the elucidation of structure-function relationships of membrane peptides and proteins. A drawback in the use of mercury-supported tBLMs with respect to gold-supported ones is represented by the difficulty in applying surface sensitive, spectroscopic and scanning probe microscopic techniques to gather information on the architecture of these biomimetic membranes. Nonetheless, mercury-supported tBLMs are definitely superior to gold-supported biomimetic membranes for the investigation of the function of membrane peptides and proteins, thanks to a fluidity and lipid lateral mobility comparable with those of bilayer lipid membranes interposed between two aqueous phases (BLMs, but with a much higher robustness and resistance to electric fields. The different features of mercury-supported tBLMs reconstituted with functionally active membrane proteins and peptides of bacteriological or pharmacological interest may be disclosed by a judicious choice of the most appropriate electrochemical techniques. We will describe the way in which electrochemical impedance spectroscopy, potential-step chronocoulometry, cyclic voltammetry and phase-sensitive AC voltammetry are conveniently employed to investigate the structure of mercury-supported tBLMs and the mode of interaction of antimicrobial peptides reconstituted into them.

  4. 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

  5. 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

  6. Antimicrobial proteins and peptides in human lung diseases: A friend and foe partnership with host proteases.

    Science.gov (United States)

    Lecaille, Fabien; Lalmanach, Gilles; Andrault, Pierre-Marie

    2016-03-01

    Lung antimicrobial proteins and peptides (AMPs) are major sentinels of innate immunity by preventing microbial colonization and infection. Nevertheless bactericidal activity of AMPs against Gram-positive and Gram-negative bacteria is compromised in patients with chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF) and asthma. Evidence is accumulating that expression of harmful human serine proteases, matrix metalloproteases and cysteine cathepsins is markedely increased in these chronic lung diseases. The local imbalance between proteases and protease inhibitors compromises lung tissue integrity and function, by not only degrading extracellular matrix components, but also non-matrix proteins. Despite the fact that AMPs are somewhat resistant to proteolytic degradation, some human proteases cleave them efficiently and impair their antimicrobial potency. By contrast, certain AMPs may be effective as antiproteases. Host proteases participate in concert with bacterial proteases in the degradation of key innate immunity peptides/proteins and thus may play immunomodulatory activities during chronic lung diseases. In this context, the present review highlights the current knowledge and recent discoveries on the ability of host enzymes to interact with AMPs, providing a better understanding of the role of human proteases in innate host defense. PMID:26341472

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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...

  12. 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...

  13. Isothermal Titration Calorimetry Studies of the Binding of a Rationally Designed Analogue of the Antimicrobial Peptide Gramicidin S to Phospholipid Bilayer Membranes†

    OpenAIRE

    Abraham, Thomas; Lewis, Ruthven N. A. H.; Hodges, Robert S.; McElhaney, Ronald N.

    2005-01-01

    The binding of the positively charged antimicrobial peptide cyclo[VKLdKVdYPLKVKLdYP] (GS14dK4) to various lipid bilayer model membranes was investigated using isothermal titration calorimetry. GS14dK4 is a diastereomeric lysine ring-size analogue of the naturally occurring antimicrobial peptide gramicidin S which exhibits enhanced antimicrobial and markedly reduced hemolytic activities compared with GS itself. Large unilamellar vesicles composed of various zwitterionic (1-palmitoyl-2-oleoyl-s...

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

    Directory of Open Access Journals (Sweden)

    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

  15. Identification of natural antimicrobial agents to treat dengue infection: In vitro analysis of latarcin peptide activity against dengue virus

    OpenAIRE

    Hussin A. Rothan; Bahrani, Hirbod; Rahman, Noorsaadah Abd; Yusof, Rohana

    2014-01-01

    Background Although there have been considerable advances in the study of dengue virus, no vaccines or anti-dengue drugs are currently available for humans. Therefore, new approaches are necessary for the development of potent anti-dengue drugs. Natural antimicrobial peptides (AMPs) with potent antiviral activities are potential hits-to-leads for antiviral drug discovery. We performed this study to identify and characterise the inhibitory potential of the latarcin peptide (Ltc 1, SMWSGMWRRKLK...

  16. 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...

  17. 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.

  18. 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.

  19. 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.

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

    Science.gov (United States)

    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

  1. A kinked antimicrobial peptide from Bombina maxima. II. Behavior in phospholipid bilayers.

    Science.gov (United States)

    Heinzmann, Ralf; Grage, Stephan L; Schalck, Constantin; Bürck, Jochen; Bánóczi, Zoltán; Toke, Orsolya; Ulrich, Anne S

    2011-04-01

    The preceding contribution by Toke et al. has studied the structure of the cationic antimicrobial peptide maximin-4 in detergent micelles and in organic solvent, revealing a different kink angle and side-chain interactions in the two different environments. Here, we have examined the same peptide in lipid bilayers using oriented circular dichroism (OCD) and solid-state (15)N nuclear magnetic resonance (NMR) in aligned samples. OCD showed that maximin-4 is helical and adopts an oblique alignment in the membrane, and lacks the characteristic realignment response that is often observed for amphipathic α-helical peptides at a peptide:lipid ratio between 1:100 and 1:20. Solid-state (15)N-NMR experiments suggest that maximin-4 also remains unaffected by lipid charge and temperature. Analyzing (15)N labels in positions Ala12, Ala13, and Leu14, an oblique tilt angle of the N-terminal helix of ~130° relative to the membrane normal was found, in good agreement with the amphiphilic profile of this segment. An additional constraint at Ala22 in the C-terminal segment is found to be compatible with a continuous α-helix, but unfavorable side-chain interactions make this solution unlikely. Instead, a kink at Gly16 seems fully compatible with all known constraints and with the biophysical expectations in the membrane-bound state, given the liquid-state NMR structures. It thus seems that the flexible kink in maximin-4 allows the two helical segments to adjust to the local environment. The irregular amphiphilic profile and the resulting versatility in shape might explain why maximin-4 lacks the realignment response that has been characteristically observed for many related frog peptides forming straight amphipathic α-helices. PMID:21312034

  2. Characterization of two antimicrobial peptides produced by a halotolerant Bacillus subtilis strain SK.DU.4 isolated from a rhizosphere soil sample

    OpenAIRE

    Baindara, Piyush; Mandal, Santi M.; Chawla, Niharika; Singh, Pradip Kumar; Pinnaka, Anil Kumar; Korpole, Suresh

    2013-01-01

    A bacterial strain producing two antimicrobial peptides was isolated from a rhizosphere soil sample and identified as Bacillus subtilis based on both phenotypic and 16S rRNA gene sequence phylogenetic analysis. It grew optimally up to 14% NaCl and produced antimicrobial peptide within 24 h of growth. The peptides were purified using a combination of chemical extraction and chromatographic techniques. The MALDI-TOF analysis of HPLC purified fractions revealed that the strain SK.DU.4 secreted a...

  3. Gallin; an antimicrobial peptide member of a new avian defensin family, the ovodefensins, has been subject to recent gene duplication

    Directory of Open Access Journals (Sweden)

    Kalina Jiri

    2010-03-01

    Full Text Available Abstract Background Egg white must provide nutrients and protection to the developing avian embryo. One way in which this is achieved is an arsenal of antimicrobial proteins and peptides which are essentially extensions of the innate immune system. Gallin is a recently identified member of a family of peptides that are found in egg white. The function of this peptide family has not been identified and they are potentially antimicrobial. Results We have confirmed that there are at least 3 forms of the gallin gene in the chicken genome in 3 separate lines of chicken, all the forms are expressed in the tubular cells of the magnum region of the oviduct, consistent with its presence in egg white. mRNA expression levels are in the order 10,000 times greater in the magnum than the shell gland. The conservation between the multiple forms of gallin in the chicken genome compared with the conservation between gallin and other avian gallin like peptides, suggests that the gene duplication has occurred relatively recently in the chicken lineage. The gallin peptide family contains a six cysteine motif (C-X5-C-X3-C-X11-C-X3-C-C found in all defensins, and is most closely related to avian beta-defensins, although the cysteine spacing differs. Further support for the classification comes from the presence of a glycine at position 10 in the 41 amino acid peptide. Recombinant gallin inhibited the growth of Escherischia coli (E. coli at a concentration of 0.25 μM confirming it as part of the antimicrobial innate immune system in avian species. Conclusions The relatively recent evolution of multiple forms of a member of a new defensin related group of peptides that we have termed ovodefensins, may be an adaptation to increase expression or the first steps in divergent evolution of the gene in chickens. The potent antimicrobial activity of the peptide against E. coli increases our understanding of the antimicrobial strategies of the avian innate immune system

  4. Cathelicidin Antimicrobial Peptide: A Novel Regulator of Islet Function, Islet Regeneration, and Selected Gut Bacteria.

    Science.gov (United States)

    Pound, Lynley D; Patrick, Christopher; Eberhard, Chandra E; Mottawea, Walid; Wang, Gen-Sheng; Abujamel, Turki; Vandenbeek, Roxanne; Stintzi, Alain; Scott, Fraser W

    2015-12-01

    Cathelicidin antimicrobial peptide (CAMP) is a naturally occurring secreted peptide that is expressed in several organs with pleiotropic roles in immunomodulation, wound healing, and cell growth. We previously demonstrated that gut Camp expression is upregulated when type 1 diabetes-prone rats are protected from diabetes development. Unexpectedly, we have also identified novel CAMP expression in the pancreatic β-cells of rats, mice, and humans. CAMP was present even in sterile rat embryo islets, germ-free adult rat islets, and neogenic tubular complexes. Camp gene expression was downregulated in young BBdp rat islets before the onset of insulitis compared with control BBc rats. CAMP treatment of dispersed islets resulted in a significant increase in intracellular calcium mobilization, an effect that was both delayed and blunted in the absence of extracellular calcium. Additionally, CAMP treatment promoted insulin and glucagon secretion from isolated rat islets. Thus, CAMP is a promoter of islet paracrine signaling that enhances islet function and glucoregulation. Finally, daily treatment with the CAMP/LL-37 peptide in vivo in BBdp rats resulted in enhanced β-cell neogenesis and upregulation of potentially beneficial gut microbes. In particular, CAMP/LL-37 treatment shifted the abundance of specific bacterial populations, mitigating the gut dysbiosis observed in the BBdp rat. Taken together, these findings indicate a novel functional role for CAMP/LL-37 in islet biology and modification of gut microbiota. PMID:26370175

  5. 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.

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

    Science.gov (United States)

    Company, Nuri; Nadal, Anna; Ruiz, Cristina; Pla, Maria

    2014-01-01

    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. PMID:25387106

  7. 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.

  8. 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

  9. 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.

  10. Expression, purification and characterization of the recombinant cysteine-rich antimicrobial peptide snakin-1 in Pichia pastoris.

    Science.gov (United States)

    Kuddus, Md Ruhul; Rumi, Farhana; Tsutsumi, Motosuke; Takahashi, Rika; Yamano, Megumi; Kamiya, Masakatsu; Kikukawa, Takashi; Demura, Makoto; Aizawa, Tomoyasu

    2016-06-01

    Snakin-1 (SN-1) is a small cysteine-rich plant antimicrobial peptide with broad spectrum antimicrobial activity which was isolated from potato (Solanum tuberosum). Here, we carried out the expression of a recombinant SN-1 in the methylotrophic yeast Pichia pastoris, along with its purification and characterization. A DNA fragment encoding the mature SN-1 was cloned into pPIC9 vector and introduced into P. pastoris. A large amount of pure recombinant SN-1 (approximately 40 mg/1L culture) was obtained from a fed-batch fermentation culture after purification with a cation exchange column followed by RP-HPLC. The identity of the recombinant SN-1 was verified by MALDI-TOF MS, CD and (1)H NMR experiments. All these data strongly indicated that the recombinant SN-1 peptide had a folding with six disulfide bonds that was identical to the native SN-1. Our findings showed that SN-1 exhibited strong antimicrobial activity against test microorganisms and produced very weak hemolysis of mammalian erythrocytes. The mechanism of its antimicrobial action against Escherichia coli was investigated by both outer membrane permeability assay and cytoplasmic membrane depolarization assay. These assays demonstrated that SN-1 is a membrane-active antimicrobial peptide which can disrupt both outer and cytoplasmic membrane integrity. This is the first report on the recombinant expression and purification of a fully active SN-1 in P. pastoris. PMID:26854372

  11. Toxicity study of antimicrobial peptides from wild bee venom and their analogs toward mammalian normal and cancer cells

    Czech Academy of Sciences Publication Activity Database

    Slaninová, Jiřina; Mlsová, V.; Kroupová, H.; Alán, Lukáš; Tůmová, Tereza; Monincová, Lenka; Borovičková, Lenka; Fučík, Vladimír; Čeřovský, Václav

    2012-01-01

    Roč. 33, č. 1 (2012), s. 18-26. ISSN 0196-9781 R&D Projects: GA ČR GA203/08/0536 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50110509 Keywords : antimicrobial peptides * venom * hymenoptera * cancer cells * toxicity * confocal microscopy Subject RIV: CE - Biochemistry Impact factor: 2.522, year: 2012

  12. Structure-activity study of macropin, a novel antimicrobial peptide from the venom of solitary bee Macropis fulvipes (Hymenoptera: Melittidae)

    Czech Academy of Sciences Publication Activity Database

    Monincová, Lenka; Veverka, Václav; Slaninová, Jiřina; Buděšínský, Miloš; Fučík, Vladimír; Bednárová, Lucie; Straka, J.; Čeřovský, Václav

    2014-01-01

    Roč. 20, č. 6 (2014), s. 375-384. ISSN 1075-2617 R&D Projects: GA ČR GA203/08/0536 Institutional support: RVO:61388963 Keywords : antimicrobial peptide * analog * wild bee venom * NMR spectroscopy * CD spectroscopy Subject RIV: CE - Biochemistry Impact factor: 1.546, year: 2014

  13. 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

  14. 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...

  15. Structural exploration of antibacterial activity and hemolytic profiles of non-natural analogs of the antimicrobial peptide mastoparan mp-8

    OpenAIRE

    Carreño, Luisa Fernanda; Lozano, José Manuel

    2013-01-01

    In this work the relevance of a systematic replacement of peptide-bonds on the Mastoparan MP-8 antimicrobial peptide to afford 27 new pseudopeptide analogues is reported. Results allowed to determine that pseudopeptides ψ-38617 (INLKALAALAKd-[CH2NH]-RLL), ψ-38629(INLKAd-[CH2NH]-LAALAKRLL) and ψ-38630 (INLK-[CH2NH]-ALAALAKRLL), showed an enhanced anti gam-negative bacterial properties, regarding the native Mastoparan MP-8 peptide, but maintaining a comparable activity against gram-positive bac...

  16. Hedistin: A novel antimicrobial peptide containing bromotryptophan constitutively expressed in the NK cells-like of the marine annelid, Nereis diversicolor.

    Science.gov (United States)

    Tasiemski, Aurélie; Schikorski, David; Le Marrec-Croq, Françoise; Pontoire-Van Camp, Christelle; Boidin-Wichlacz, Céline; Sautière, Pierre-Eric

    2007-01-01

    A novel antimicrobial peptide, named hedistin was identified from the coelomocytes of Nereis diversicolor. Hedistin shows no obvious similarities with other known peptides and constitutes the first antimicrobial peptide containing bromotryptophans demonstrated in annelids. cDNA and mass spectrometry analysis revealed that, upon bacteria challenge, this peptide is secreted following processing of a precursor containing a signal peptide and prosequences. Hedistin was shown to possess an activity against a large spectrum of bacteria including the methicillin resistant Staphylococcus aureus and Vibrio alginolyticus. The gene was demonstrated to be constitutively and exclusively expressed in circulating NK cells like known to play an important role in the immunity of the sand worm. These data contrast with those observed in another annelid, the leech, in which genes coding for antimicrobial peptides are upregulated in a specific tissue and peptides are rapidly released into the hemolymph after septic injury. PMID:17210178

  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. 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.

  19. 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

  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. 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

  2. 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

  3. 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

  4. Structural and functional evaluation of the palindromic alanine-rich antimicrobial peptide Pa-MAP2.

    Science.gov (United States)

    Migliolo, Ludovico; Felício, Mário R; Cardoso, Marlon H; Silva, Osmar N; Xavier, Mary-Ann E; Nolasco, Diego O; de Oliveira, Adeliana Silva; Roca-Subira, Ignasi; Vila Estape, Jordi; Teixeira, Leandro D; Freitas, Sonia M; Otero-Gonzalez, Anselmo J; Gonçalves, Sónia; Santos, Nuno C; Franco, Octavio L

    2016-07-01

    Recently, several peptides have been studied regarding the defence process against pathogenic microorganisms, which are able to act against different targets, with the purpose of developing novel bioactive compounds. The present work focuses on the structural and functional evaluation of the palindromic antimicrobial peptide Pa-MAP2, designed based on the peptide Pa-MAP from Pleuronectes americanus. For a better structural understanding, molecular modelling analyses were carried out, together with molecular dynamics and circular dichroism, in different media. Antibacterial activity against Gram-negative and positive bacteria was evaluated, as well as cytotoxicity against human erythrocytes, RAW 264.7, Vero and L6 cells. In silico docking experiments, lipid vesicle studies, and atomic force microscopy (AFM) imaging were carried out to explore the activity of the peptide. In vivo studies on infected mice were also done. The palindromic primary sequence favoured an α-helix structure that was pH dependent, only present on alkaline environment, with dynamic N- and C-terminals that are stabilized in anionic media. Pa-MAP2 only showed activity against Gram-negative bacteria, with a MIC of 3.2μM, and without any cytotoxic effect. In silico, lipid vesicles and AFM studies confirm the preference for anionic lipids (POPG, POPS, DPPE, DPPG and LPS), with the positively charged lysine residues being essential for the initial electrostatic interaction. In vivo studies showed that Pa-MAP2 increases to 100% the survival rate of mice infected with Escherichia coli. Data here reported indicated that palindromic Pa-MAP2 could be an alternative candidate for use in therapeutics against Gram-negative bacterial infections. PMID:27063608

  5. Spacer-free BODIPY fluorogens in antimicrobial peptides for direct imaging of fungal infection in human tissue

    Science.gov (United States)

    Mendive-Tapia, Lorena; Zhao, Can; Akram, Ahsan R.; Preciado, Sara; Albericio, Fernando; Lee, Martin; Serrels, Alan; Kielland, Nicola; Read, Nick D; Lavilla, Rodolfo; Vendrell, Marc

    2016-01-01

    Fluorescent antimicrobial peptides are promising structures for in situ, real-time imaging of fungal infection. Here we report a fluorogenic probe to image Aspergillus fumigatus directly in human pulmonary tissue. We have developed a fluorogenic Trp-BODIPY amino acid with a spacer-free C-C linkage between Trp and a BODIPY fluorogen, which shows remarkable fluorescence enhancement in hydrophobic microenvironments. The incorporation of our fluorogenic amino acid in short antimicrobial peptides does not impair their selectivity for fungal cells, and enables rapid and direct fungal imaging without any washing steps. We have optimized the stability of our probes in human samples to perform multi-photon imaging of A. fumigatus in ex vivo human tissue. The incorporation of our unique BODIPY fluorogen in biologically relevant peptides will accelerate the development of novel imaging probes with high sensitivity and specificity. PMID:26956772

  6. 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.

  7. 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

  8. The application of antimicrobial peptides as growth and health promoters for swine.

    Science.gov (United States)

    Xiao, Hao; Shao, Fangyuan; Wu, Miaomiao; Ren, Wenkai; Xiong, Xia; Tan, Bie; Yin, Yulong

    2015-01-01

    With the widespread ban on the use of antibiotics in swine feed, alternative measures need to be sought to maintain swine health and performance. Antimicrobial peptides (AMPs) are part of the nonspecific defense system and are natural antibiotics produced by plants, insects, mammalians, and micro-organisms as well as by chemical synthesis. Due to their broad microbicidal activity against various fungi, bacteria and enveloped viruses, AMPs are a potential alternative to conventional antibiotics for use in swine production. This review focuses on the structure and mechanism of action of AMPs, as well as their effects on performance, immune function and intestinal health in pigs. The aim is to provide support for the application of AMPs as feed additives replacing antibiotics in swine nutrition. PMID:26019864

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    molecule. In particular, surface plasmon resonance (SPR) sensors have been already demonstrated suitable for food-safety control, label-free screening for various disease markers in bodily fluids, as well as for real-time continuous monitoring of drug levels in intensive care environment. We envisage such...... sensors to be integrated into wireless communication infrastructure for e-health and environmental monitoring applications. One of the important threats in hospital environment is multi-resistant organisms that are not affected by common antibiotics. The growth of multi-resistant infections spurred 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 of...

  10. Kit for instant 99mTc labeling of the antimicrobial peptide ubiquicidin 29-41

    International Nuclear Information System (INIS)

    The ubiquicidin 29-41 fragment (UBI) is a cationic antimicrobial peptide. An instant kit formulation was developed for the preparation of 99mTc-UBI 29-41 in high radiochemical yield and its use as an infection imaging agent in humans was evaluated. The components were selected to produce a direct 99mTc labeling, presumably to the amine groups of Lys and Arg7. 99mTc-UBI 29-41 obtained from the lyophilized kit showed radiochemical purity of >97% with an average target/non-target ratio of 2.3±0.6 in positive infection sites at 2 hours. Kits were stable at 4 deg C for over 6 months. (author)

  11. Constitutive expression of transgenes encoding derivatives of the synthetic antimicrobial peptide BP100: impact on rice host plant fitness

    Directory of Open Access Journals (Sweden)

    Nadal Anna

    2012-09-01

    Full Text Available Abstract Background The Biopeptide BP100 is a synthetic and strongly cationic α-helical undecapeptide with high, specific antibacterial activity against economically important plant-pathogenic bacteria, and very low toxicity. It was selected from a library of synthetic peptides, along with other peptides with activities against relevant bacterial and fungal species. Expression of the BP100 series of peptides in plants is of major interest to establish disease-resistant plants and facilitate molecular farming. Specific challenges were the small length, peptide degradation by plant proteases and toxicity to the host plant. Here we approached the expression of the BP100 peptide series in plants using BP100 as a proof-of-concept. Results Our design considered up to three tandemly arranged BP100 units and peptide accumulation in the endoplasmic reticulum (ER, analyzing five BP100 derivatives. The ER retention sequence did not reduce the antimicrobial activity of chemically synthesized BP100 derivatives, making this strategy possible. Transformation with sequences encoding BP100 derivatives (bp100der was over ten-fold less efficient than that of the hygromycin phosphotransferase (hptII transgene. The BP100 direct tandems did not show higher antimicrobial activity than BP100, and genetically modified (GM plants constitutively expressing them were not viable. In contrast, inverted repeats of BP100, whether or not elongated with a portion of a natural antimicrobial peptide (AMP, had higher antimicrobial activity, and fertile GM rice lines constitutively expressing bp100der were produced. These GM lines had increased resistance to the pathogens Dickeya chrysanthemi and Fusarium verticillioides, and tolerance to oxidative stress, with agronomic performance comparable to untransformed lines. Conclusions Constitutive expression of transgenes encoding short cationic α-helical synthetic peptides can have a strong negative impact on rice fitness. However, GM

  12. IL-4 and IL-13 exposure during mucociliary differentiation of bronchial epithelial cells increases antimicrobial activity and expression of antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    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

  13. 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

  14. A novel immune evasion strategy of candida albicans: proteolytic cleavage of a salivary antimicrobial peptide.

    Science.gov (United States)

    Meiller, Timothy F; Hube, Bernhard; Schild, Lydia; Shirtliff, Mark E; Scheper, Mark A; Winkler, Robert; Ton, Amy; Jabra-Rizk, Mary Ann

    2009-01-01

    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 first defined

  15. A novel immune evasion strategy of candida albicans: proteolytic cleavage of a salivary antimicrobial peptide.

    Directory of Open Access Journals (Sweden)

    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

  16. 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.

  17. 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.

  18. 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.

  19. Sex, offspring and carcass determine antimicrobial peptide expression in the burying beetle.

    Science.gov (United States)

    Jacobs, Chris G C; Steiger, Sandra; Heckel, David G; Wielsch, Natalie; Vilcinskas, Andreas; Vogel, Heiko

    2016-01-01

    The burying beetle Nicrophorus vespilloides has emerged as a model system for the investigation of adaptations that allow the utilization of carrion as a diet and as a resource for reproduction. The survival of beetles and their offspring given their exposure to soil-dwelling and cadaver-borne microbes requires mechanisms that reduce bacterial contamination in the diet and that achieve sanitation of the microhabitat. To explore the role of antimicrobial peptides (AMPs) in this context, we analyzed burying beetle males and females at different stages of their breeding cycle using the RNA-Seq and proteomics approaches. To address variation in immune functions, we investigated the impact of adult sex, the presence or absence of offspring (social context), and the presence of carrion (environmental context) on the expression of the identified immune effector genes. We found that particular AMPs are sex-specific and tightly regulated by the presence of a carcass or offspring and identified the two most context-dependent antimicrobial proteins in anal secretions. The context-specific expression dynamics of particular AMPs and lysozymes reveals a complex regulatory system, reflecting adaptations to specific ecological niches. This study highlights how burying beetles cope with microorganisms found on carrion and identifies candidates for both internal and external immunity. PMID:27139635

  20. Effects of the substitution of amino acid residues, through chemical synthesis, on the conformation and activity of antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    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

  1. Antimicrobial peptides and proteins in mycobacterial therapy: current status and future prospects.

    Science.gov (United States)

    Padhi, Avinash; Sengupta, Mitali; Sengupta, Srabasti; Roehm, Klaus H; Sonawane, Avinash

    2014-07-01

    Tuberculosis (TB), an infectious disease caused by the pathogen Mycobacterium tuberculosis (Mtb), kills about 1.5 million people every year worldwide. An increase in the prevalence of drug-resistant strains of Mtb in the last few decades now necessitates the development of novel drugs that combat infections by both drug-sensitive and resistant Mtb. Moreover, as Mtb can persist in host cells by modulating their immune responses, it is essential that anti-TB agents be able to penetrate macrophages and kill the pathogen intracellularly without harming the host cells. In this context, antimicrobial peptides (AMPs) and proteins are being harnessed as anti-infective agents for the treatment of various diseases. Due to their direct and rapid bactericidal activity it is unlikely that pathogens acquire resistance against AMPs. Several short and potent AMP derivatives have been prepared by peptide engineering, and several of them are currently evaluated in clinical trials. The present review summarizes the role of endogenously expressed AMPs and proteins in the treatment of tuberculosis infections. In addition, mechanisms of direct anti-mycobacterial activity, manipulation of host immune responses, and future prospects of AMPs as therapeutic agents are discussed. PMID:24813349

  2. 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.

  3. Covalent modification of a ten-residue cationic antimicrobial peptide with levofloxacin

    Directory of Open Access Journals (Sweden)

    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.

  4. 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

  5. Safety Study of an Antimicrobial Peptide Lactocin 160, Produced by the Vaginal Lactobacillus rhamnosus

    Directory of Open Access Journals (Sweden)

    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.

  6. 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

  7. 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

  8. 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

  9. Mechanism of antibacterial action of a synthetic peptide with an Ala-peptoid residue based on the scorpion-derived antimicrobial peptide IsCT.

    Science.gov (United States)

    Lim, Shin Saeng; Yoon, Sang-Pil; Park, Yoonkyoung; Zhu, Wan Long; Park, Il-Seon; Hahm, Kyung-Soo; Shin, Song Yub

    2006-09-01

    A novel bacterial cell-selective antimicrobial peptide, IsCT-P (ILKKIWKPIKKLF-NH(2)), was designed based on the scorpion-derived alpha-helical antimicrobial peptide, IsCT. Here, we investigated the effect of substituting Pro(8) of IsCT-P with the Ala-peptoid residue (N-methylglycine) on the peptide's structure and mechanism of action. Circular dichroism analysis revealed that the modified peptide, IsCT-a, has a much lower alpha-helicity than IsCT-P in membrane mimicking conditions, suggesting the peptoid residue provides much more structural flexibility than the proline residue. IsCT-a was also much less effective than IsCT-P at causing leakage of fluorescent dye entrapped within negatively charged vesicles and at dissipating the membrane potential of Staphylococcus aureus. Collectively, our results suggest that the antibacterial action of IsCT-a is due to the inhibition of intracellular targets rather than the disruption and depolarization of bacterial cell membranes. PMID:16871429

  10. Improved bioactivity of antimicrobial peptides by addition of amino-terminal copper and nickel (ATCUN) binding motifs.

    Science.gov (United States)

    Libardo, M Daben; Cervantes, Jorge L; Salazar, Juan C; Angeles-Boza, Alfredo M

    2014-08-01

    Antimicrobial peptides (AMPs) are promising candidates to help circumvent antibiotic resistance, which is an increasing clinical problem. Amino-terminal copper and nickel (ATCUN) binding motifs are known to actively form reactive oxygen species (ROS) upon metal binding. The combination of these two peptidic constructs could lead to a novel class of dual-acting antimicrobial agents. To test this hypothesis, a set of ATCUN binding motifs were screened for their ability to induce ROS formation, and the most potent were then used to modify AMPs with different modes of action. ATCUN binding motif-containing derivatives of anoplin (GLLKRIKTLL-NH2), pro-apoptotic peptide (PAP; KLAKLAKKLAKLAK-NH2), and sh-buforin (RAGLQFPVGRVHRLLRK-NH2) were synthesized and found to be more active than the parent AMPs against a panel of clinically relevant bacteria. The lower minimum inhibitory concentration (MIC) values for the ATCUN-anoplin peptides are attributed to the higher pore-forming activity along with their ability to cause ROS-induced membrane damage. The addition of the ATCUN motifs to PAP also increases its ability to disrupt membranes. DNA damage is the major contributor to the activity of the ATCUN-sh-buforin peptides. Our findings indicate that the addition of ATCUN motifs to AMPs is a simple strategy that leads to AMPs with higher antibacterial activity and possibly to more potent, usable antibacterial agents. PMID:24803240

  11. A kinked antimicrobial peptide from Bombina maxima. I. Three-dimensional structure determined by NMR in membrane-mimicking environments.

    Science.gov (United States)

    Toke, Orsolya; Bánóczi, Zoltán; Király, Péter; Heinzmann, Ralf; Bürck, Jochen; Ulrich, Anne S; Hudecz, Ferenc

    2011-04-01

    Maximin-4 is a 27-residue cationic antimicrobial peptide exhibiting selectivity for bacterial cells. As part of the innate defense system in the Chinese red-belly toad, its mode of action is thought to be ion channel or pore formation and dissipation of the electrochemical gradient across the pathogenic cell membrane. Here we present the high-resolution structure of maximin-4 in two different membrane mimetics, sodium dodecyl sulfate micelles and 50% methanol, as determined by (1)H solution NMR spectroscopy. In both environments, the peptide chain adopts a helix-break-helix conformation following a highly disordered N-terminal segment. Despite the similarities in the overall topology of the two structures, major differences are observed in terms of the interactions stabilizing the kink region and the arrangement of the four lysine residues. This has a marked influence on the shape and charge distribution of the molecule and may have implications for the bacterial selectivity of the peptide. The solution NMR results are complemented by CD spectroscopy and solid-state NMR experiments in lipid bilayers, both confirming the predominantly helical conformation of the peptide. As a first step in elucidating the membrane interactions of maximin-4, our study contributes to a better understanding of the mode of action of antimicrobial peptides and the factors governing their selectivity. PMID:21234559

  12. Pancreatic β-Cells Limit Autoimmune Diabetes via an Immunoregulatory Antimicrobial Peptide Expressed under the Influence of the Gut Microbiota.

    Science.gov (United States)

    Sun, Jia; Furio, Laetitia; Mecheri, Ramine; van der Does, Anne M; Lundeberg, Erik; Saveanu, Loredana; Chen, Yongquan; van Endert, Peter; Agerberth, Birgitta; Diana, Julien

    2015-08-18

    Antimicrobial peptides (AMPs) expressed by epithelial and immune cells are largely described for the defense against invading microorganisms. Recently, their immunomodulatory functions have been highlighted in various contexts. However how AMPs expressed by non-immune cells might influence autoimmune responses in peripheral tissues, such as the pancreas, is unknown. Here, we found that insulin-secreting β-cells produced the cathelicidin related antimicrobial peptide (CRAMP) and that this production was defective in non-obese diabetic (NOD) mice. CRAMP administrated to prediabetic NOD mice induced regulatory immune cells in the pancreatic islets, dampening the incidence of autoimmune diabetes. Additional investigation revealed that the production of CRAMP by β-cells was controlled by short-chain fatty acids produced by the gut microbiota. Accordingly, gut microbiota manipulations in NOD mice modulated CRAMP production and inflammation in the pancreatic islets, revealing that the gut microbiota directly shape the pancreatic immune environment and autoimmune diabetes development. PMID:26253786

  13. Influence of Cysteine and Tryptophan Substitution on DNA-Binding Activity on Maize α-Hairpinin Antimicrobial Peptide.

    Science.gov (United States)

    Sousa, Daniel A; Porto, William F; Silva, Maria Z; da Silva, Tatiane R; Franco, Octávio L

    2016-01-01

    For almost four decades, antimicrobial peptides have been studied, and new classes are being discovered. However, for therapeutic use of these molecules, issues related to the mechanism of action must be answered. In this work, the antimicrobial activity of the hairpinin MBP-1 was studied by the synthesis of two variants, one replacing cysteines and one tryptophan with alanine. Antibacterial activity was abolished in both variants. No membrane disturbance, even in concentrations higher than those required to inhibit the bacteria, was observed in SEM microscopy. The gel retardation assay showed that MBP-1 possesses a higher DNA-binding ability than variants. Finally, molecular modelling showed that the lack of cysteines resulted in structure destabilization and lack of tryptophan resulted in a less flexible peptide, with less solvent assessable surface area, both characteristics that could contribute to absence of activity. In summary, the data here reported add more information about the multiple mechanisms of action of α-hairpinins. PMID:27529210

  14. 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

  15. Repulsive casimir forces

    International Nuclear Information System (INIS)

    We discuss repulsive Casimir forces between dielectric materials with nontrivial magnetic susceptibility. It is shown that considerations based on the naive pairwise summation of van der Waals and Casimir-Polder forces may not only give an incorrect estimate of the magnitude of the total Casimir force but even the wrong sign of the force when materials with high dielectric and magnetic responses are involved. Indeed repulsive Casimir forces may be found in a large range of parameters, and we suggest that the effect may be realized in known materials. The phenomenon of repulsive Casimir forces may be of importance both for experimental study and for nanomachinery applications

  16. Comparison of innate immune agonists for induction of tracheal antimicrobial peptide gene expression in tracheal epithelial cells of cattle

    OpenAIRE

    Berghuis, Lesley; Abdelaziz, Khaled Taha; Bierworth, Jodi; Wyer, Leanna; Jacob, Gabriella; Karrow, Niel A; Sharif, Shayan; Clark, Mary Ellen; Caswell, Jeff L

    2014-01-01

    Bovine respiratory disease is a complex of bacterial and viral infections of economic and welfare importance to the beef industry. Although tracheal antimicrobial peptide (TAP) has microbicidal activity against bacterial pathogens causing bovine respiratory disease, risk factors for bovine respiratory disease including BVDV and stress (glucocorticoids) have been shown to inhibit the induced expression of this gene. Lipopolysaccharide is known to stimulate TAP gene expression, but the maximum ...

  17. Expression and Significance of the HIP/PAP and RegIIIγ Antimicrobial Peptides during Mammalian Urinary Tract Infection

    OpenAIRE

    Spencer, John David; Jackson, Ashley R.; Li, Birong; Ching, Christina B.; Vonau, Martin; Easterling, Robert S.; Schwaderer, Andrew L.; McHugh, Kirk M.; Becknell, Brian

    2015-01-01

    Recent evidence indicates that antimicrobial peptides (AMPs) serve key roles in defending the urinary tract against invading uropathogens. To date, the individual contribution of AMPs to urinary tract host defense is not well defined. In this study, we identified Regenerating islet-derived 3 gamma (RegIIIγ) as the most transcriptionally up-regulated AMP in murine bladder transcriptomes following uropathogenic Escherichia coli (UPEC) infection. We confirmed induction of RegIIIγ mRNA during cys...

  18. Interplay between Bladder Microbiota and Urinary Antimicrobial Peptides: Mechanisms for Human Urinary Tract Infection Risk and Symptom Severity

    OpenAIRE

    Nienhouse, Vanessa; Gao, Xiang; Dong, Qunfeng; Nelson, David E; Toh, Evelyn; McKinley, Kathleen; Schreckenberger, Paul; Shibata, Noriko; Cynthia S Fok; Mueller, Elizabeth R.; Brubaker, Linda; Wolfe, Alan J.; Katherine A Radek

    2014-01-01

    Resident bacterial communities (microbiota) and host antimicrobial peptides (AMPs) are both essential components of normal host innate immune responses that limit infection and pathogen induced inflammation. However, their interdependence has not been investigated in the context of urinary tract infection (UTI) susceptibility. Here, we explored the interrelationship between the urinary microbiota and host AMP responses as mechanisms for UTI risk. Using prospectively collected day of surgery (...

  19. Alanine Esters of Enterococcal Lipoteichoic Acid Play a Role in Biofilm Formation and Resistance to Antimicrobial Peptides

    OpenAIRE

    Fabretti, Francesca; Theilacker, Christian; Baldassarri, Lucilla; Kaczynski, Zbigniew; Kropec, Andrea; Holst, Otto; Huebner, Johannes

    2006-01-01

    Enterococcus faecalis is among the predominant causes of nosocomial infections. Surface molecules like d-alanine lipoteichoic acid (LTA) perform several functions in gram-positive bacteria, such as maintenance of cationic homeostasis and modulation of autolytic activities. The aim of the present study was to evaluate the effect of d-alanine esters of teichoic acids on biofilm production and adhesion, autolysis, antimicrobial peptide sensitivity, and opsonic killing. A deletion mutant of the d...

  20. Design and analysis of structure-activity relationship of novel antimicrobial peptides derived from the conserved sequence of cecropin.

    Science.gov (United States)

    Hao, Gang; Shi, Yong-Hui; Han, Jing-Hui; Li, Qi-Hui; Tang, Ya-Li; Le, Guo-Wei

    2008-03-01

    We have de novo designed four antimicrobial peptides AMP-A/B/C/D, the 51-residues peptides, which are based on the conserved sequence of cecropin. In the present study, the four peptides were chemically synthesized and their activities assayed. Their secondary structure, amphipathic property, electric field distribution and transmembrane domain were subsequently predicted by bioinformatics tools. Finally, the structure-activity relationship was analyzed from the results of activity experiments and prediction. The results of activity experiments indicated that AMP-B/C/D clearly possessed excellent broad-spectrum activity against bacteria, whereas AMP-A was almost inactive against most of the bacterial strains tested. AMP-B/C/D showed more potent activity against Gram-positive bacteria than against Gram-negative bacteria. By utilizing bioinformatics analysis tools, we found that the secondary structure of the four cation peptides was mainly alpha-helix, and the result of CD spectrum also displayed that all the peptides had considerable alpha-helix in the presence of either 50% TFE or SDS micelles. AMP-C showed much better activity than other peptides against most of the bacteria tested, owing to its remarkable cation property and the amphipathic character of its N-terminal. The study of structure-activity relationship of the designed peptides confirmed that amphipathic structure and high net positive charge were prerequisites for maintaining their activities. PMID:17929330

  1. Friend, foe or food? Recognition and the role of antimicrobial peptides in gut immunity and Drosophila-microbe interactions.

    Science.gov (United States)

    Broderick, Nichole A

    2016-05-26

    Drosophila melanogaster lives, breeds and feeds on fermenting fruit, an environment that supports a high density, and often a diversity, of microorganisms. This association with such dense microbe-rich environments has been proposed as a reason that D. melanogaster evolved a diverse and potent antimicrobial peptide (AMP) response to microorganisms, especially to combat potential pathogens that might occupy this niche. Yet, like most animals, D. melanogaster also lives in close association with the beneficial microbes that comprise its microbiota, or microbiome, and recent studies have shown that antimicrobial peptides (AMPs) of the epithelial immune response play an important role in dictating these interactions and controlling the host response to gut microbiota. Moreover, D. melanogaster also eats microbes for food, consuming fermentative microbes of decaying plant material and their by-products as both larvae and adults. The processes of nutrient acquisition and host defence are remarkably similar and use shared functions for microbe detection and response, an observation that has led to the proposal that the digestive and immune systems have a common evolutionary origin. In this manner, D. melanogaster provides a powerful model to understand how, and whether, hosts differentiate between the microbes they encounter across this spectrum of associations.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160597

  2. Interaction of acylated and substituted antimicrobial peptide analogs with phospholipid-polydiacetylene vesicles. Correlation with their biological properties.

    Science.gov (United States)

    Siano, Alvaro; Húmpola, María V; Rey, María C; Simonetta, Arturo; Tonarelli, Georgina G

    2011-07-01

    A series of peptide analogs based on region 6-22 of Plantaricin 149 sequence were synthesized. The interaction between these analogs and phospholipid-polydiacetylene vesicles was investigated to evaluate the ability of the bioassay to detect differences in the interaction of the peptides with dipalmitoylphosphatidylglycerol and dipalmitoylphosphatidylcholine vesicles, associated with amino acid substitution and N-terminal conjugation of the sequences with short fatty acids (8 and 12 carbon atoms). Fatty acid conjugation of peptides with low antimicrobial activity resulted in lipopeptides with improved activity against strains of Staphylococcus aureus and Listeria monocytogenes. The length of the fatty acid determined the bacterial specificity, and the conjugation with n-octanoic acid yielded the most active analog (C8-CT) against Staphylococcus aureus strain (MIC: 1.0 μm) while the conjugation with n-dodecanoic acid (C12-CT) was optimal for Listeria monocytogenes strain (MIC: 2.0 μm). In contrast, the substitution of Phe by Trp had an unfavorable effect on the antimicrobial activity. Hemolysis tests and membrane interaction studies with dipalmitoylphosphatidylcholine-polydiacetylene vesicles showed that lipopeptides interact to a greater extent with both biological and biomimetic membranes. Also, a good correlation was found between antimicrobial activity against Staphylococcus aureus strain and % colorimetric response values with dipalmitoylphosphatidylglycerol-polydiacetylene vesicles. PMID:21496212

  3. Effect of antimicrobial peptides on colistin-susceptible and colistin-resistant strains of Klebsiella pneumoniae and Enterobacter asburiae.

    Science.gov (United States)

    Kádár, Béla; Kocsis, Béla; Kristof, Katalin; Tóth, Ákos; Szabó, Dóra

    2015-12-01

    In this study susceptibility to different antimicrobial peptides was investigated on colistin-susceptible and colistin-resistant identical pulsotype strains of KPC-2 producing Klebsiella pneumoniae ST258 as well as colistin-susceptible and colistin-resistant Enterobacter asburiae strains isolated from clinical samples. In our test, bacteria were exposed to 50 mg/ml lactoferrin, lysozyme and protamine - cationic antimicrobial peptides belonging to innate immune system and having structural similarity to polymyxins - in separate reactions. After 18 hours incubation of colonies were counted. 40% of colistin-resistant K. pneumoniae strains and 97% of colistin-susceptible counterpart strains were lysed by protamine whereas 87% and 100% colony forming unit decrease by lysozyme was seen, respectively. In the case of colistin-resistant E. asburiae strains 1 log10 cell count increase were observed after treatment with lysozyme and 1.56 log10 after lactoferrin exposure compared to the initial number whereas the colistin-susceptible showed no relevant cell count increase. Our findings suggest that acquired colistin-resistance in Enterobacteriaceae is associated with tolerance against antimicrobial peptides. PMID:26689883

  4. 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.

  5. Identification and functional characterization of an uncharacterized antimicrobial peptide from a ciliate Paramecium caudatum.

    Science.gov (United States)

    Cui, Pengfei; Dong, Yuan; Li, Zhijian; Zhang, Yubo; Zhang, Shicui

    2016-07-01

    The global ever-growing concerns about multi-drug resistant (MDR) microbes leads to urgent demands for exploration of new antibiotics including antimicrobial peptides (AMPs). Here we demonstrated that a cDNA from Ciliata Paramecium caudatum, designated Pcamp1, coded for a protein with features characteristic of AMPs, which is not homologous to any AMPs currently known. Both the C-terminal 91 amino acid residues of PcAMP1, cPcAMP1, expressed in Escherichia coli and the C-terminal 26 amino acid residues (predicted mature AMP), cPcAMP1/26, synthesized, underwent a coil-to-helix transition in the presence of TFE, SDS or DPC. Functional assays revealed that cPcAMP1 and cPcAMP1/26 were both able to kill Aeromonas hydrophila and Staphylococcus aureus. ELISA showed that cPcAMP1 and cPcAMP1/26 were able to bind to microbe-associated molecular pattern molecules LPS and LTA, which was further corroborated by the observations that cPcAMP1 could deposit onto the bacterial membranes. Importantly, both cPcAMP1 and cPcAMP1/26 were able to induce bacterial membrane permeabilization and depolarization, and to increase intracellular ROS levels. Additionally, cPcAMP1 and cPcAMP1/26 were not cytotoxic to mammalian cells. Taken together, our results show that PcAMP1 is a potential AMP with a membrane selectivity towards bacterial cells, which renders it a promising template for the design of novel peptide antibiotics against MDR microbes. It also shows that use of signal conserved sequence of AMPs can be an effective tool to identify potential AMPs across different animal classes. PMID:26883426

  6. Critical Role of Antimicrobial Peptide Cathelicidin for Controlling Helicobacter pylori Survival and Infection.

    Science.gov (United States)

    Zhang, Lin; Wu, William K K; Gallo, Richard L; Fang, Evandro F; Hu, Wei; Ling, Thomas K W; Shen, Jing; Chan, Ruby L Y; Lu, Lan; Luo, Xiao M; Li, Ming X; Chan, Kam M; Yu, Jun; Wong, Vincent W S; Ng, Siew C; Wong, Sunny H; Chan, Francis K L; Sung, Joseph J Y; Chan, Matthew T V; Cho, Chi H

    2016-02-15

    The antimicrobial peptide cathelicidin is critical for protection against different kinds of microbial infection. This study sought to elucidate the protective action of cathelicidin against Helicobacter pylori infection and its associated gastritis. Exogenous cathelicidin was found to inhibit H. pylori growth, destroy the bacteria biofilm, and induce morphological alterations in H. pylori membrane. Additionally, knockdown of endogenous cathelicidin in human gastric epithelial HFE-145 cells markedly increased the intracellular survival of H. pylori. Consistently, cathelicidin knockout mice exhibited stronger H. pylori colonization, higher expression of proinflammatory cytokines IL-6, IL-1β, and ICAM1, and lower expression of the anti-inflammatory cytokine IL-10 in the gastric mucosa upon H. pylori infection. In wild-type mice, H. pylori infection also stimulated gastric epithelium-derived cathelicidin production. Importantly, pretreatment with bioengineered Lactococcus lactis that actively secretes cathelicidin significantly increased mucosal cathelicidin levels and reduced H. pylori infection and the associated inflammation. Moreover, cathelicidin strengthened the barrier function of gastric mucosa by stimulating mucus synthesis. Collectively, these findings indicate that cathelicidin plays a significant role as a potential natural antibiotic for H. pylori clearance and a therapeutic agent for chronic gastritis. PMID:26800870

  7. Evidence for synergism of the antimicrobial peptide piscidin 2 with antiparasitic and antioomycete drugs.

    Science.gov (United States)

    Zahran, E; Noga, E J

    2010-12-01

    Piscidins are potent, broad-spectrum, host-produced antimicrobial peptides (AMPs) that appear to constitute the most common AMP family in teleost fish. Here, we show that piscidin 2 has potent activity against the water mould Saprolegnia, one of the most important pathogens of freshwater fish. The minimum oomyceticidal concentration (MOC₁₀₀) of piscidin 2 against zoospores of three pathogenic isolates of Saprolegnia ranged from 12.5 to 25.0 μg mL⁻¹. This piscidin concentration is well within levels that have been estimated to be present in at least some fish (1-32.5 μg mL⁻¹). In the presence of either copper or malachite green, two drugs commonly used to treat water moulds, there was evidence for partial synergism (PSYN) with piscidin 2. There was also evidence for PSYN after exposure of the ciliate parasite Tetrahymena pyriformis to piscidin 2 plus copper. Our data provide further evidence that piscidins may be an important host defence against skin and gill pathogens and that the piscidin levels in host tissue might influence the success of drug treatments. PMID:21091726

  8. Cationic synthetic peptides: assessment of their antimicrobial potency in liquid preserved boar semen.

    Directory of Open Access Journals (Sweden)

    Stephanie Speck

    Full Text Available Various semen extender formulas are in use to maintain sperm longevity and quality whilst acting against bacterial contamination in liquid sperm preservation. Aminoglycosides are commonly supplemented to aid in the control of bacteria. As bacterial resistance is increasing worldwide, antimicrobial peptides (AMPs received lively interest as alternatives to overcome multi-drug resistant bacteria. We investigated, whether synthetic cationic AMPs might be a suitable alternative for conventional antibiotics in liquid boar sperm preservation. The antibacterial activity of two cyclic AMPs (c-WWW, c-WFW and a helical magainin II amide analog (MK5E was studied in vitro against two Gram-positive and eleven Gram-negative bacteria. Isolates included ATCC reference strains, multi-resistant E. coli and bacteria cultured from boar semen. Using broth microdilution, minimum inhibitory concentrations were determined for all AMPs. All AMPs revealed activity towards the majority of bacteria but not against Proteus spp. (all AMPs and Staphylococcus aureus ATCC 29213 (MK5E. We could also demonstrate that c-WWW and c-WFW were effective against bacterial growth in liquid preserved boar semen in situ, especially when combined with a small amount of gentamicin. Our results suggest that albeit not offering a complete alternative to traditional antibiotics, the use of AMPs offers a promising solution to decrease the use of conventional antibiotics and thereby limit the selection of multi-resistant strains.

  9. Butyrate enhances disease resistance of chickens by inducing antimicrobial host defense peptide gene expression.

    Science.gov (United States)

    Sunkara, Lakshmi T; Achanta, Mallika; Schreiber, Nicole B; Bommineni, Yugendar R; Dai, Gan; Jiang, Weiyu; Lamont, Susan; Lillehoj, Hyun S; Beker, Ali; Teeter, Robert G; Zhang, Guolong

    2011-01-01

    Host defense peptides (HDPs) constitute a large group of natural broad-spectrum antimicrobials and an important first line of immunity in virtually all forms of life. Specific augmentation of synthesis of endogenous HDPs may represent a promising antibiotic-alternative approach to disease control. In this study, we tested the hypothesis that exogenous administration of butyrate, a major type of short-chain fatty acids derived from bacterial fermentation of undigested dietary fiber, is capable of inducing HDPs and enhancing disease resistance in chickens. We have found that butyrate is a potent inducer of several, but not all, chicken HDPs in HD11 macrophages as well as in primary monocytes, bone marrow cells, and jejuna and cecal explants. In addition, butyrate treatment enhanced the antibacterial activity of chicken monocytes against Salmonella enteritidis, with a minimum impact on inflammatory cytokine production, phagocytosis, and oxidative burst capacities of the cells. Furthermore, feed supplementation with 0.1% butyrate led to a significant increase in HDP gene expression in the intestinal tract of chickens. More importantly, such a feeding strategy resulted in a nearly 10-fold reduction in the bacterial titer in the cecum following experimental infections with S. enteritidis. Collectively, the results indicated that butyrate-induced synthesis of endogenous HDPs is a phylogenetically conserved mechanism of innate host defense shared by mammals and aves, and that dietary supplementation of butyrate has potential for further development as a convenient antibiotic-alternative strategy to enhance host innate immunity and disease resistance. PMID:22073293

  10. Serpin-15 from Bombyx mori inhibits prophenoloxidase activation and expression of antimicrobial peptides.

    Science.gov (United States)

    Liu, Dongran; Wang, Lei; Yang, Liu; Qian, Cen; Wei, Guoqing; Dai, Lishang; Li, Jun; Zhu, Baojian; Liu, Chaoliang

    2015-07-01

    Serine protease inhibitors (SPIs) play a key role in physiological responses by controlling protease activities. In this study, we studied the biochemical functions of serpin-15, an SPI, from Bombyx mori (Bmserpin-15). Recombinant Bmserpin-15 was expressed in Escherichia coli cells and used to raise rabbit anti-Bmserpin-15 polyclonal antibodies. Bmserpin-15 mRNA and protein expression was detected in all tested tissues, particularly in the fat body and silk gland. After challenge with four different microorganisms (Escherichia coli, Beauveria bassiana, Micrococcus luteus and B. mori nuclear polyhedrosis virus), the expressions of Bmserpin-15 mRNA and protein were induced significantly, particularly by B. bassiana and M. luteus. Recombinant Bmserpin-15 inhibited prophenoloxidase activation, but did not affect phenoloxidase activity, in B. mori hemolymph. Injection of recombinant Bmserpin-15 into B. mori larvae reduced significantly the transcript levels of antimicrobial peptides in fat body. Our results suggested that Bmserpin-15 plays an important role in the innate immunity of B. mori. PMID:25720980

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

    Science.gov (United States)

    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

  12. Insect antimicrobial peptides: potential tools for the prevention of skin cancer.

    Science.gov (United States)

    Tonk, Miray; Vilcinskas, Andreas; Rahnamaeian, Mohammad

    2016-09-01

    Antimicrobial peptides/proteins (AMPs) are biologically active molecules with diverse structural properties that are produced by mammals, plants, insects, ticks, and microorganisms. They have a range of antibacterial, antifungal, antiviral, and even anticancer activities, and their biological properties could therefore be exploited for therapeutic and prophylactic applications. Cancer and cancer drug resistance are significant current health challenges, so the development of innovative cancer drugs with minimal toxicity toward normal cells and novel modes of action that can evade resistance may provide a new direction for anticancer therapy. The skin is the first line of defense against heat, sunlight, injury, and infection, and skin cancer is thus the most common type of cancer. The skin that has been exposed to sunlight is particularly susceptible, but lesions can occur anywhere on the body. Skin cancer awareness and self-efficacy are necessary to improve sun protection behavior, but more effective preventative approaches are also required. AMPs may offer a new prophylactic approach against skin cancer. In this mini review, we draw attention to the potential use of insect AMPs for the prevention and treatment of skin cancer. PMID:27418360

  13. Molecular resolution visualization of a pore formed by trichogin, an antimicrobial peptide, in a phospholipid matrix.

    Science.gov (United States)

    Smetanin, Maxim; Sek, Slawomir; Maran, Flavio; Lipkowski, Jacek

    2014-12-01

    Electrochemical scanning tunneling microscopy (EC-STM) was employed to study the aggregation of trichogin OMe (TCG), an antimicrobial peptide, incorporated into a lipid monolayer. High-resolution EC-STM images show that trichogin molecules aggregate to form channels in the lipid monolayer. Two types of aggregates were observed in the images. The first consisted of a bundle of six TCG molecules surrounding a central pore. The structure and dimensions of this channel are similar to aggregates that in bilayers are described by the barrel-stave model. The EC-STM images also reveal that channels aggregate further to form a hexagonal lattice of a two dimensional (2D) nanocrystal. The model of 2D lattice was built from trimers of TCG molecules that alternatingly are oriented with either hydrophilic or hydrophobic faces to each other. In this way each TCG molecule is oriented partially with its hydrophilic face towards the hexameric pore allowing the formation of the column of water inside this pore. PMID:25157669

  14. OPTICAL AND DIELECTRIC SENSORS BASED ON ANTIMICROBIAL PEPTIDES FOR MICROORGANISMS DIAGNOSIS

    Directory of Open Access Journals (Sweden)

    CesarAugusto SouzaAndrade

    2014-08-01

    Full Text Available Antimicrobial peptides (AMPs are natural compounds isolated from a wide variety of organisms that include microorganisms, insects, amphibians, plants and humans. These biomolecules are considered as part of the innate immune system and are known as natural antibiotics, presenting a broad spectrum of activities against bacteria, fungi and/or viruses. Technological innovations have enabled AMPs to be utilized for the development of novel biodetection devices. Advances in nanotechnology, such as the synthesis of nanocomposites, nanoparticles, and nanotubes have permitted the development of nanostructured platforms with biocompatibility and greater surface areas for the immobilization of biocomponents, arising as additional tools for obtaining more efficient biosensors. Diverse AMPs have been used as biological recognition elements for obtaining biosensors with more specificity and lower detection limits, whose analytical response can be evaluated through electrochemical impedance and fluorescence spectroscopies. AMP-based biosensors have shown potential for applications such as supplementary tools for conventional diagnosis methods of microorganisms. In this review, conventional methods for microorganism diagnosis as well new strategies using AMPs for the development of impedimetric and fluorescent biosensors are highlighted. AMP-based biosensors show promise as methods for diagnosing infections and bacterial contaminations as well as applications in quality control for clinical analyses and microbiological laboratories.

  15. A splice variant of PGRP-LC required for expression of antimicrobial peptides in Anopheles gambiae

    Institute of Scientific and Technical Information of China (English)

    HUI LIN; LINGMIN ZHANG; CORALIA LUNA; NGO T.HOA; LIANGBIAO ZHENG

    2007-01-01

    Members of the peptidoglycan recognition protein (PGRP) family play essential roles in different manifestations of immune responses in insects. PGRP-LC, one of seven members of this family in the malaria vector Anopheles gambiae produced several spliced variants. Here we show that PGRP-LC, and not other members of the PGRP family nor the six members of the Gram-negative binding protein families, is required for the expression of antimicrobial peptide genes (such as CEC1 and GAM1) under the control of the Imd-Rel2 pathway in an A. gambiae cell line, 4a3A. PGRP-LC produces many splice variants that can be classified into three sub-groups (LC1, LC2 and LC3), based on the carboxyl terminal sequences. RNA interference against one LC1 sub-group resulted in dramatic reduction of CEC1 and GAM1. Over-expression of LC1 a and to a lesser extent LC3a (a member of the LC1 and LC3 sub-group, respectively) in the 4a3A cell line enhances the expression of CEC1 and GAM1. These results demonstrate that the LC1-subgroup splice variants are essential for the expression of CEC1 and GAM1 in A. gambiae cell line.

  16. Complement-related proteins control the flavivirus infection of Aedes aegypti by inducing antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Xiaoping Xiao

    2014-04-01

    Full Text Available The complement system functions during the early phase of infection and directly mediates pathogen elimination. The recent identification of complement-like factors in arthropods indicates that this system shares common ancestry in vertebrates and invertebrates as an immune defense mechanism. Thioester (TE-containing proteins (TEPs, which show high similarity to mammalian complement C3, are thought to play a key role in innate immunity in arthropods. Herein, we report that a viral recognition cascade composed of two complement-related proteins limits the flaviviral infection of Aedes aegypti. An A. aegypti macroglobulin complement-related factor (AaMCR, belonging to the insect TEP family, is a crucial effector in opposing the flaviviral infection of A. aegypti. However, AaMCR does not directly interact with DENV, and its antiviral effect requires an A. aegypti homologue of scavenger receptor-C (AaSR-C, which interacts with DENV and AaMCR simultaneously in vitro and in vivo. Furthermore, recognition of DENV by the AaSR-C/AaMCR axis regulates the expression of antimicrobial peptides (AMPs, which exerts potent anti-DENV activity. Our results both demonstrate the existence of a viral recognition pathway that controls the flaviviral infection by inducing AMPs and offer insights into a previously unappreciated antiviral function of the complement-like system in arthropods.

  17. How can a beta-sheet peptide be both a potent antimicrobial and harmfully toxic? Molecular dynamics simulations of protegrin-1 in micelles

    DEFF Research Database (Denmark)

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

    2006-01-01

    In this work, the naturally occurring beta-hairpin antimicrobial peptide protegrin-1 (PG-1) is studied by molecular dynamics simulation in all-atom sodium dodecylsulfate and dodecylphosphocholine micelles. These simulations provide a high-resolution picture of the interactions between the peptide...

  18. Physiologically-Relevant Modes of Membrane Interactions by the Human Antimicrobial Peptide, LL-37, Revealed by SFG Experiments

    Science.gov (United States)

    Ding, Bei; Soblosky, Lauren; Nguyen, Khoi; Geng, Junqing; Yu, Xinglong; Ramamoorthy, Ayyalusamy; Chen, Zhan

    2013-05-01

    Antimicrobial peptides (AMPs) could become the next generation antibiotic compounds which can overcome bacterial resistance by disrupting cell membranes and it is essential to determine the factors underlying its mechanism of action. Although high-resolution NMR and other biological studies have provided valuable insights, it has been a major challenge to follow the AMP-membrane interactions at physiologically-relevant low peptide concentrations. In this study, we demonstrate a novel approach to overcome this major limitation by performing Sum Frequency Generation (SFG) vibrational spectroscopic experiments on lipid bilayers containing an AMP, LL-37. Our results demonstrate the power of SFG to study non-linear helical peptides and also infer that lipid-peptide interaction and the peptide orientation depend on the lipid membrane composition. The observed SFG signal changes capture the aggregating process of LL-37 on membrane. In addition, our SFG results on cholesterol-containing lipid bilayers indicate the inhibition effect of cholesterol on peptide-induced membrane permeation process.

  19. Integration of antimicrobial peptides with gold nanoparticles as unique non-viral vectors for gene delivery to mesenchymal stem cells with antibacterial activity.

    Science.gov (United States)

    Peng, Li-Hua; Huang, Yan-Fen; Zhang, Chen-Zhen; Niu, Jie; Chen, Ying; Chu, Yang; Jiang, Zhi-Hong; Gao, Jian-Qing; Mao, Zheng-Wei

    2016-10-01

    Gold nanoparticles (AuNPs) have emerged as attractive non-viral gene vectors. However their application in regenerative medicine is still limited partially due to a lack of an intrinsic capacity to transfect difficult-to-transfect cells such as primary cells or stem cells. In current study, we report the synthesis of antimicrobial peptide conjugated cationic AuNPs (AuNPs@PEP) as highly efficient carriers for gene delivery to stem cells with antibacterial ability. The AuNPs@PEP integrate the advantages of cationic AuNPs and antibacterial peptides: the presence of cationic AuNPs can effectively condense DNA and the antimicrobial peptides are essential for the cellular & nucleus entry enhancement to achieve high transfection efficiency and antibacterial ability. As a result, antimicrobial peptides conjugated AuNPs significantly promoted the gene transfection efficiency in rat mesenchymal stem cells than pristine AuNPs, with a similar extent to those expressed by TAT (a well-known cell-penetrating peptide) modified AuNPs. More interestingly, the combinational system has better antibacterial ability than free antimicrobial peptides in vitro and in vivo, possibly due to the high density of peptides on the surface of AuNPs. Finally we present the concept-proving results that AuPs@PEP can be used as a carrier for in vivo gene activation in tissue regeneration, suggesting its potential as a multifunctional system with both gene delivery and antibacterial abilities in clinic. PMID:27376562

  20. The PDB database is a rich source of alpha-helical anti-microbial peptides to combat disease causing pathogens.

    Science.gov (United States)

    Chakraborty, Sandeep; Phu, My; de Morais, Tâmara Prado; Nascimento, Rafael; Goulart, Luiz Ricardo; Rao, Basuthkar J; Asgeirsson, Bjarni; Dandekar, Abhaya M

    2014-01-01

    The therapeutic potential of α-helical anti-microbial peptides (AH-AMP) to combat pathogens is fast gaining prominence. Based on recently published open access software for characterizing α-helical peptides (PAGAL), we elucidate a search methodology (SCALPEL) that leverages the massive structural data pre-existing in the PDB database to obtain AH-AMPs belonging to the host proteome. We provide in vitro validation of SCALPEL on plant pathogens ( Xylella fastidiosa, Xanthomonas arboricola and Liberibacter crescens) by identifying AH-AMPs that mirror the function and properties of cecropin B, a well-studied AH-AMP. The identified peptides include a linear AH-AMP present within the existing structure of phosphoenolpyruvate carboxylase (PPC20), and an AH-AMP mimicing the properties of the two α-helices of cecropin B from chitinase (CHITI25). The minimum inhibitory concentration of these peptides are comparable to that of cecropin B, while anionic peptides used as control failed to show any inhibitory effect on these pathogens. Substitute therapies in place of conventional chemotherapies using membrane permeabilizing peptides like these might also prove effective to target cancer cells. The use of native structures from the same organism could possibly ensure that administration of such peptides will be better tolerated and not elicit an adverse immune response. We suggest a similar approach to target Ebola epitopes, enumerated using PAGAL recently, by selecting suitable peptides from the human proteome, especially in wake of recent reports of cationic amphiphiles inhibiting virus entry and infection. PMID:26629331

  1. Interaction of the antimicrobial peptide polymyxin B1 with both membranes of E. coli: a molecular dynamics study.

    Directory of Open Access Journals (Sweden)

    Nils A Berglund

    2015-04-01

    Full Text Available Antimicrobial peptides are small, cationic proteins that can induce lysis of bacterial cells through interaction with their membranes. Different mechanisms for cell lysis have been proposed, but these models tend to neglect the role of the chemical composition of the membrane, which differs between bacterial species and can be heterogeneous even within a single cell. Moreover, the cell envelope of Gram-negative bacteria such as E. coli contains two membranes with differing compositions. To this end, we report the first molecular dynamics simulation study of the interaction of the antimicrobial peptide, polymyxin B1 with complex models of both the inner and outer membranes of E. coli. The results of >16 microseconds of simulation predict that polymyxin B1 is likely to interact with the membranes via distinct mechanisms. The lipopeptides aggregate in the lipopolysaccharide headgroup region of the outer membrane with limited tendency for insertion within the lipid A tails. In contrast, the lipopeptides readily insert into the inner membrane core, and the concomitant increased hydration may be responsible for bilayer destabilization and antimicrobial function. Given the urgent need to develop novel, potent antibiotics, the results presented here reveal key mechanistic details that may be exploited for future rational drug development.

  2. Production of the antimicrobial peptide UBI 29-41 labelled with 99mTc by an indirect method

    International Nuclear Information System (INIS)

    The infection processes are a major problem in human health causing a high number of human deaths all around the world. Diagnostic imaging in nuclear medicine is an attractive option in the detection of infection processes due to its sensitivity. The antimicrobial peptides are very important in the development of new radiopharmaceuticals, since their antimicrobial activity towards a great variety of microorganisms have been proven. The aim of this work was to obtain the antimicrobial peptide UBI 29-41 labelled with technetium 99 m, by an indirect method via NHS-Hynic and tricine as a coligand, and evaluate its stability and its ability to discriminate between infection and inflammation sites. The radiochemical purity of the labeling procedure was 95.5±1,2 %. The cysteine challenge showed a great stability of the 99mTc UBI-Hynic, and the stability in human serum showed that the 81% of the radioactivity remained bounded to UBI-Hynic at 48 hs of incubation. The bio distribution's studies showed main elimination via kidney of 99mTc UBI-Hynic and the target/non target ratio was 1,81 for infected mice and 1,16 for inflamed mice. (author)

  3. Identification and expression analysis of a novel stylicin antimicrobial peptide from Kuruma shrimp (Marsupenaeus japonicus).

    Science.gov (United States)

    Liu, Hong-tao; Wang, Jun; Mao, Yong; Liu, Min; Niu, Su-fang; Qiao, Ying; Su, Yong-quan; Wang, Chun-zhong; Zheng, Zhi-peng

    2015-12-01

    Antimicrobial peptides (AMPs) are important components of the innate immune system and function as the first line of defense against invading pathogens. In current study we identified, cloned and characterized a novel stylicin AMP from Kuruma shrimp Marsupenaeus japonicus (Mj-sty). The full-length cDNA of Mj-sty was 428 bp with an open reading frame of 315 bp that encoded 104 amino acids. The theoretical molecular mass of mature Mj-sty was 8.693 kDa with an isoelectric point (pI) of 4.79. A proline-rich N-terminal region and a C-terminal region contained 13 cysteine residues were identified. Genomic sequence analysis with respect to its cDNA showed that Mj-sty was organized into two exons interrupted by one intron. Tissue-specific expression revealed that Mj-sty was mainly transcribed in gills and hemocytes. Expression of Mj-sty in early developmental stages demonstrated that Mj-sty mRNA were present from fertilized eggs to post-larvae of 17 days (PL17), and the expression levels showed a significant variation in different developmental stages. After challenge of white spot syndrome virus (WSSV), the time-dependent expression pattern of Mj-sty in both gills and hepatopancrease showed down-regulation at the early hours of infection, subsequently up-regulation and down-regulation, and then up-regulation at the end hours to almost the half of the controls. The results indicate that Mj-sty is potentially involved in the ontogenesis and immune responses against WSSV. PMID:26439413

  4. 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

  5. Society for general microbiology - 148th ordinary meeting. Activities and actions of antimicrobial peptides. 26-30 March 2001, Edinburgh, UK.

    Science.gov (United States)

    McMichael, J W; Sallenave, J M

    2001-06-01

    The rapidly expanding field of antimicrobial peptides is one that is attracting increasing interest from research groups around the world. The importance of antimicrobial agents in providing alternatives to conventional antibiotics has been highlighted in recent years by the emergence of a number of multidrug-resistant pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Indeed, bacteria refractory to treatment by all known antibiotics are now a reality and the need for developing novel antimicrobial agents is urgent. This meeting brought together researchers working in a number of varied, but ultimately related areas. The functional diversity and putative mechanisms of action of antimicrobial peptides were discussed in depth, along with recent developments in the design of synthetic peptides with enhanced antimicrobial properties. Several ongoing studies were described, ranging from research into cystic fibrosis to work in the food industry. It was emphasized that cationic antimicrobial peptides have a range of properties to offer the world of scientific research and may play an important role in the ongoing battle against pathogenic microorganisms. Oral presentation sessions of the conference were co-chaired by Dr Deirdre A Devine (University of Leeds, UK) and Dr David G Smith (University of Edinburgh, UK). PMID:16001309

  6. High CO2 concentration as an inductor agent to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories.

    Science.gov (United States)

    Ruiz, Cristina; Pla, Maria; Company, Nuri; Riudavets, Jordi; Nadal, Anna

    2016-03-01

    Cationic α-helical antimicrobial peptides such as BP100 are of increasing interest for developing novel phytosanitary or therapeutic agents and products with industrial applications. Biotechnological production of these peptides in plants can be severely impaired due to the toxicity exerted on the host by high-level expression. This can be overcome by using inducible promoters with extremely low activity throughout plant development, although the yields are limited. We examined the use of modified atmospheres using the increased levels of [CO2], commonly used in the food industry, as the inductor agent to biotechnologically produce phytotoxic compounds with higher yields. Here we show that 30% [CO2] triggered a profound transcriptional response in rice leaves, including a change in the energy provision from photosynthesis to glycolysis, and the activation of stress defense mechanisms. Five genes with central roles in up-regulated pathways were initially selected and their promoters successfully used to drive the expression of phytotoxic BP100 in genetically modified (GM) rice. GM plants had a normal phenotype on development and seed production in non-induction conditions. Treatment with 30 % [CO2] led to recombinant peptide accumulation of up to 1 % total soluble protein when the Os.hb2 promoter was used. This is within the range of biotechnological production of other peptides in plants. Using BP100 as a proof-of-concept we demonstrate that very high [CO2] can be considered an economically viable strategy to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories. PMID:26687131

  7. Dermaseptins and Magainins: Antimicrobial Peptides from Frogs' Skin—New Sources for a Promising Spermicides Microbicides—A Mini Review

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    Amira Zairi

    2009-01-01

    Full Text Available Sexually transmitted infections (STIs and human immunodeficiency virus (HIV, the causative agents of acquired immunodeficiency syndrome (AIDS, are two great concerns in the reproductive health of women. Thus, the challenge is to find products with a double activity, on the one hand having antimicrobial/antiviral properties with a role in the reduction of STI, and on the other hand having spermicidal action to be used as a contraceptive. In the absence of an effective microbicide along with the disadvantages of the most commonly used spermicidal contraceptive worldwide, nonoxynol-9, new emphasis has been focused on the development of more potential intravaginal microbicidal agents. Topical microbicides spermicides would ideally provide a female-controlled method of self-protection against HIV as well as preventing pregnancies. Nonoxynol-9, the only recommended microbicide spermicide, damages cervicovaginal epithelium because of its membrane-disruptive properties. Clearly, there is an urgent need to identify new compounds with dual potential microbicidal properties; antimicrobial peptides should be candidates for such investigations. Dermaseptins and magainins are two classes of cationic, amphipathic α-helical peptides that have been identified in the skin extracts of frogs Phyllomedusa sauvagei and Xenopus laevis. Regarding their contraceptive activities and their effect against various STI-causing pathogens, we believe that these two peptides are appropriate candidates in the evaluation of newer and safer microbicides spermicides in the future.

  8. Leptoglycin: a new Glycine/Leucine-rich antimicrobial peptide isolated from the skin secretion of the South American frog Leptodactylus pentadactylus (Leptodactylidae).

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    Sousa, Juliana C; Berto, Raquel F; Gois, Elicélia A; Fontenele-Cardi, Nauíla C; Honório, José E R; Konno, Katsuhiro; Richardson, Michael; Rocha, Marcos F G; Camargo, Antônio A C M; Pimenta, Daniel C; Cardi, Bruno A; Carvalho, Krishnamurti M

    2009-07-01

    Antimicrobial peptides are components of innate immunity that is the first-line defense against invading pathogens for a wide range of organisms. Here, we describe the isolation, biological characterization and amino acid sequencing of a novel neutral Glycine/Leucine-rich antimicrobial peptide from skin secretion of Leptodactylus pentadactylus named leptoglycin. The amino acid sequence of the peptide purified by RP-HPLC (C(18) column) was deduced by mass spectrometric de novo sequencing and confirmed by Edman degradation: GLLGGLLGPLLGGGGGGGGGLL. Leptoglycin was able to inhibit the growth of Gram-negative bacteria Pseudomonas aeruginosa, Escherichia coli and Citrobacter freundii with minimal inhibitory concentrations (MICs) of 8 microM, 50 microM, and 75 microM respectively, but it did not show antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus, Micrococcus luteus and Enterococcus faecalis), yeasts (Candida albicans and Candida tropicalis) and dermatophytes fungi (Microsporum canis and Trichophyton rubrum). No hemolytic activity was observed at the 2-200 microM range concentration. The amino acid sequence of leptoglycin with high level of glycine (59.1%) and leucine (36.4%) containing an unusual central proline suggests the existence of a new class of Gly/Leu-rich antimicrobial peptides. Taken together, these results suggest that this natural antimicrobial peptide could be a tool to develop new antibiotics. PMID:19298834

  9. Cell-to-cell contact and antimicrobial peptides play a combined role in the death of Lachanchea thermotolerans during mixed-culture alcoholic fermentation with Saccharomyces cerevisiae.

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    Kemsawasd, Varongsiri; Branco, Patrícia; Almeida, Maria Gabriela; Caldeira, Jorge; Albergaria, Helena; Arneborg, Nils

    2015-07-01

    The roles of cell-to-cell contact and antimicrobial peptides in the early death of Lachanchea thermotolerans CBS2803 during anaerobic, mixed-culture fermentations with Saccharomyces cerevisiae S101 were investigated using a commercially available, double-compartment fermentation system separated by cellulose membranes with different pore sizes, i.e. 1000 kDa for mixed- and single-culture fermentations, and 1000 and 3.5-5 kDa for compartmentalized-culture fermentations. SDS-PAGE and gel filtration chromatography were used to determine an antimicrobial peptidic fraction in the fermentations. Our results showed comparable amounts of the antimicrobial peptidic fraction in the inner compartments of the mixed-culture and 1000 kDa compartmentalized-culture fermentations containing L. thermotolerans after 4 days of fermentation, but a lower death rate of L. thermotolerans in the 1000 kDa compartmentalized-culture fermentation than in the mixed-culture fermentation. Furthermore, L. thermotolerans died off even more slowly in the 3.5-5 kDa than in the 1000 kDa compartmentalized-culture fermentation, which coincided with the presence of less of the antimicrobial peptidic fraction in the inner compartment of that fermentation than of the 1000 kDa compartmentalized-culture fermentation. Taken together, these results indicate that the death of L. thermotolerans in mixed cultures with S. cerevisiae is caused by a combination of cell-to-cell contact and antimicrobial peptides. PMID:26109361

  10. Nucleation and Growth of Ordered Arrays of Silver Nanoparticles on Peptide Nanofibers: Hybrid Nanostructures with Antimicrobial Properties.

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    Pazos, Elena; Sleep, Eduard; Rubert Pérez, Charles M; Lee, Sungsoo S; Tantakitti, Faifan; Stupp, Samuel I

    2016-05-01

    Silver nanoparticles have been of great interest as plasmonic substrates for sensing and imaging, catalysts, or antimicrobial systems. Their physical properties are strongly dependent on parameters that remain challenging to control such as size, chemical composition, and spatial distribution. We report here on supramolecular assemblies of a novel peptide amphiphile containing aldehyde functionality in order to reduce silver ions and subsequently nucleate silver metal nanoparticles in water. This system spontaneously generates monodisperse silver particles at fairly regular distances along the length of the filamentous organic assemblies. The metal-organic hybrid structures exhibited antimicrobial activity and significantly less toxicity toward eukaryotic cells. Metallized organic nanofibers of the type described here offer the possibility to create hydrogels, which integrate the useful functions of silver nanoparticles with controllable metallic content. PMID:27103596

  11. Polyvinyl alcohol nanofiber formulation of the designer antimicrobial peptide APO sterilizes Acinetobacter baumannii-infected skin wounds in mice.

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    Sebe, Istvan; Ostorhazi, Eszter; Fekete, Aron; Kovacs, Krisztian N; Zelko, Romana; Kovalszky, Ilona; Li, Wenyi; Wade, John D; Szabo, Dora; Otvos, Laszlo

    2016-01-01

    Native and designer cationic antimicrobial peptides are increasingly acknowledged as host defense molecules rather than true antimicrobials. Due to their ability to activate the innate immune system, these structures are used to treat uninfected and bacterially-infected wounds, including those harboring Acinetobacter baumannii. Previously we documented that when administered intramuscularly or topically in liquid formulations, the proline-rich host defense peptide dimer A3-APO accelerates uninfected wound re-epithelization and eliminates systemic and local A. baumannii, methicillin-resistant Staphylococcus aureus and other pathogen load from infected lesions better than conventional antibiotics. In the current study we sought to produce and characterize a novel delivery system, suitable for immediate and convenient application in non-hospital environments. The APO monomer was incorporated into polyvinyl alcohol nanofibers and the complex was polymerized into a solid patch dressing. Mice were subjected to skin abrasion where the wounds were either left uninfected or were inoculated with a near lethal dose of multidrug resistant A. baumannii strain. Analyzed after 3 days, APO monomer-containing patches improved wound appearance significantly better than polymer patches without antibiotics. When compared to colistin, the APO patches accelerated wound healing, and statistically significantly reduced wound size and wound bacterial load. The in vivo antimicrobial effect was more extensive than after intramuscular administration of the peptide drug, by using only one tenth of the active pharmaceutical ingredient. These data suggest that the APO monomer-impregnated nanofiber dressing can be developed as an economical first-line treatment option to skin injuries in general and battlefield burn and blast injuries in particular. PMID:26319645

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

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    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.

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

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    Williams P

    2008-10-01

    Full Text Available Abstract Background The successful interaction of bacterial pathogens with host tissues requires the sensing of specific chemical and physical cues. The human gut contains a huge number of neurons involved in the secretion and sensing of a class of neuroendocrine hormones called catecholamines. Recently, in Escherichia coli O157:H7, the catecholamines adrenaline and noradrenaline were shown to act synergistically with a bacterial quorum sensing molecule, autoinducer 3 (AI-3, to affect bacterial virulence and motility. We wished to investigate the impact of adrenaline on the biology of Salmonella spp. Results We have determined the effect of adrenaline on the transcriptome of the gut pathogen Salmonella enterica serovar Typhimurium. Addition of adrenaline led to an induction of key metal transport systems within 30 minutes of treatment. The oxidative stress responses employing manganese internalisation were also elicited. Cells lacking the key oxidative stress regulator OxyR showed reduced survival in the presence of adrenaline and complete restoration of growth upon addition of manganese. A significant reduction in the expression of the pmrHFIJKLM antimicrobial peptide resistance operon reduced the ability of Salmonella to survive polymyxin B following addition of adrenaline. Notably, both phenotypes were reversed by the addition of the β-adrenergic blocker propranolol. Our data suggest that the BasSR two component signal transduction system is the likely adrenaline sensor mediating the antimicrobial peptide response. Conclusion Salmonella are able to sense adrenaline and downregulate the antimicrobial peptide resistance pmr locus through the BasSR two component signalling system. Through iron transport, adrenaline may affect the oxidative stress balance of the cell requiring OxyR for normal growth. Both adrenaline effects can be inhibited by the addition of the β-adrenergic blocker propranolol. Adrenaline sensing may provide an environmental

  14. Development of antimicrobial peptide defenses of southern leopard frogs, Rana sphenocephala, against the pathogenic chytrid fungus, Batrachochytrium dendrobatidis.

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    Holden, Whitney M; Reinert, Laura K; Hanlon, Shane M; Parris, Matthew J; Rollins-Smith, Louise A

    2015-01-01

    Amphibian species face the growing threat of extinction due to the emerging fungal pathogen Batrachochytrium dendrobatidis, which causes the disease chytridiomycosis. Antimicrobial peptides (AMPs) produced in granular glands of the skin are an important defense against this pathogen. Little is known about the ontogeny of AMP production or the impact of AMPs on potentially beneficial symbiotic skin bacteria. We show here that Rana (Lithobates) sphenocephala produces a mixture of four AMPs with activity against B. dendrobatidis, and we report the minimum inhibitory concentration (MIC) of synthesized replicates of these four AMPs tested against B. dendrobatidis. Using mass spectrometry and protein quantification assays, we observed that R. sphenocephala does not secrete a mature suite of AMPs until approximately 12 weeks post-metamorphosis, and geographically disparate populations produce a different suite of peptides. Use of norepinephrine to induce maximal secretion significantly reduced levels of culturable skin bacteria. PMID:25218643

  15. Effect of antimicrobial peptide on the dynamics of phosphocholine membrane: role of cholesterol and physical state of bilayer.

    Science.gov (United States)

    Sharma, V K; Mamontov, E; Anunciado, D B; O'Neill, H; Urban, V S

    2015-09-14

    Antimicrobial peptides are universal in all forms of life and are well known for their strong interaction with the cell membrane. This makes them a popular target for investigation of peptide-lipid interactions. Here we report the effect of melittin, an important antimicrobial peptide, on the dynamics of membranes based on 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid in both the solid gel and fluid phases. To probe the phase transition, elastic neutron intensity temperature scans have been carried out on DMPC-based unilamellar vesicles (ULV) with and without melittin. We have found that addition of a small amount (0.2 mol%) melittin eliminates the steep fall in the elastic intensity at 296 K associated with the solid gel to fluid phase transition, which is observed for pure DMPC vesicles. Quasielastic neutron scattering (QENS) experiments have been carried out on DMPC ULV in the solid gel and fluid phases with and without 0.2 mol% melittin. The data analysis invariably shows the presence of lateral and internal motions of the DMPC molecule. We found that melittin does have a profound effect on the dynamics of lipid molecules, especially on the lateral motion, and affects it in a different way, depending on the phase of the bilayers. In the solid gel phase, it acts as a plasticizer, enhancing the lateral motion of DMPC. However, in the fluid phase it acts as a stiffening agent, restricting the lateral motion of the lipid molecules. These observations are consistent with the mean squared displacements extracted from the elastic intensity temperature scans. Their importance lies in the fact that many membrane processes, including signaling and energy transduction pathways, are controlled to a great extent by the lateral diffusion of lipids in the membrane. To investigate the effect of melittin on vesicles supplemented with cholesterol, QENS experiments have also been carried out on DMPC ULV with cholesterol in the presence and absence of 0.2 mol% melittin

  16. Characterization of two antimicrobial peptides produced by a halotolerant Bacillus subtilis strain SK.DU.4 isolated from a rhizosphere soil sample.

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    Baindara, Piyush; Mandal, Santi M; Chawla, Niharika; Singh, Pradip Kumar; Pinnaka, Anil Kumar; Korpole, Suresh

    2013-01-01

    A bacterial strain producing two antimicrobial peptides was isolated from a rhizosphere soil sample and identified as Bacillus subtilis based on both phenotypic and 16S rRNA gene sequence phylogenetic analysis. It grew optimally up to 14% NaCl and produced antimicrobial peptide within 24 h of growth. The peptides were purified using a combination of chemical extraction and chromatographic techniques. The MALDI-TOF analysis of HPLC purified fractions revealed that the strain SK.DU.4 secreted a bacteriocin-like peptide with molecular mass of 5323.9 Da and a surface-active lipopeptide (m/z 1056 Da). The peptide mass fingerprinting of low-molecular-weight bacteriocin exhibited significant similarity with stretches of secreted lipoprotein of Methylomicrobium album BG8 and displayed 70% sequence coverage. MALDI MS/MS analysis elucidated the lipopeptide as a cyclic lipopeptide with a β-hydroxy fatty acid linked to Ser of a peptide with seven α-amino acids (Asp-Tyr-Asn-Gln-Pro-Asn-Ser) and assigned it to iturin-like group of antimicrobial biosurfactants. However, it differed in amino acid composition with other members of the iturin family. Both peptides were active against Gram-positive bacteria, suggesting that they had an additive effect. PMID:23289832

  17. The role of C-terminal amidation in the membrane interactions of the anionic antimicrobial peptide, maximin H5.

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    Dennison, Sarah R; Mura, Manuela; Harris, Frederick; Morton, Leslie H G; Zvelindovsky, Andrei; Phoenix, David A

    2015-05-01

    Maximin H5 is an anionic antimicrobial peptide from amphibians, which carries a C-terminal amide moiety, and was found to be moderately haemolytic (20%). The α-helicity of the peptide was 42% in the presence of lipid mimics of erythrocyte membranes and was found able to penetrate (10.8 mN m(-1)) and lyse these model membranes (64 %). In contrast, the deaminated peptide exhibited lower levels of haemolysis (12%) and α-helicity (16%) along with a reduced ability to penetrate (7.8 m Nm(-1)) and lyse (55%) lipid mimics of erythrocyte membranes. Taken with molecular dynamic simulations and theoretical analysis, these data suggest that native maximin H5 primarily exerts its haemolytic action via the formation of an oblique orientated α-helical structure and tilted membrane insertion. However, the C-terminal deamination of maximin H5 induces a loss of tilted α-helical structure, which abolishes the ability of the peptide's N-terminal and C-terminal regions to H-bond and leads to a loss in haemolytic ability. Taken in combination, these observations strongly suggest that the C-terminal amide moiety carried by maximin H5 is required to stabilise the adoption of membrane interactive tilted structure by the peptide. Consistent with previous reports, these data show that the efficacy of interaction and specificity of maximin H5 for membranes can be attenuated by sequence modification and may assist in the development of variants of the peptide with the potential to serve as anti-infectives. PMID:25640709

  18. An integrated study on antimicrobial activity and ecotoxicity of quantum dots and quantum dots coated with the antimicrobial peptide indolicidin

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    Galdiero E

    2016-08-01

    Full Text Available Emilia Galdiero,1 Antonietta Siciliano,1 Valeria Maselli,1 Renato Gesuele,1 Marco Guida,1 Domenico Fulgione,1 Stefania Galdiero,2 Lucia Lombardi,3 Annarita Falanga2 1Department of Biology, University of Naples “Federico II”, Naples, Italy; 2Department of Pharmacy and Cirpeb, University of Naples “Federico II”, Naples, Italy; 3Department of Experimental Medicine, Second University of Naples, Naples, Italy Abstract: This study attempts to evaluate the antimicrobial activity and the ecotoxicity of quantum dots (QDs alone and coated with indolicidin. To meet this objective, we tested the level of antimicrobial activity on Gram-positive and Gram-negative bacteria, and we designed an ecotoxicological battery of test systems and indicators able to detect different effects using a variety of end points. The antibacterial activity was analyzed against Staphylococcus aureus (ATCC 6538, Pseudomonas aeruginosa (ATCC 1025, Escherichia coli (ATCC 11229, and Klebsiella pneumoniae (ATCC 10031, and the results showed an improved germicidal action of QDs-Ind. Toxicity studies on Daphnia magna indicated a decrease in toxicity for QDs-Ind compared to QDs alone, lack of bioluminescence inhibition on Vibrio fisheri, and no mutations in Salmonella typhimurium TA 100. The comet assay and oxidative stress experiments performed on D. magna showed a genotoxic and an oxidative damage with a dose–response trend. Indolicidin retained its activity when bound to QDs. We observed an enhanced activity for QDs-Ind. The presence of indolicidin on the surface of QDs was able to decrease its QDs toxicity. Keywords: peptide, quantum dots, ecotoxicity, antimicrobial activity, oxidative stress, genotoxicity

  19. Microbial challenge promotes the regenerative process of the injured central nervous system of the medicinal leech by inducing the synthesis of antimicrobial peptides in neurons and microglia

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    Schikorski, David; Cuvillier-Hot, Virginie; Leippe, Matthias; Boidin-Wichlacz, Céline; Slomianny, Christian; Macagno, Eduardo; Salzet, Michel; Tasiemski, Aurélie

    2010-01-01

    Following trauma, the central nervous system (CNS) of the medicinal leech, unlike the mammalian CNS, has a strong capacity to regenerate neurites and synaptic connections that restore normal function. Here, we show that this regenerative process is enhanced by a controlled bacterial infection, suggesting that induction of regeneration of normal CNS function may depend critically upon the co-initiation of an immune response. We explore the interaction between the activation of a neuroimmune response and the process of regeneration by assaying the potential roles of two newly characterized antimicrobial peptides. Our data provide evidence that microbial components differentially induce the transcription, by microglial cells, of both antimicrobial peptide genes, the products of which accumulate rapidly at sites in the CNS undergoing regeneration following axotomy. Using a preparation of leech CNS depleted of microglial cells, we also demonstrate the production of antimicrobial peptides by neurons. Interestingly, in addition to exerting antibacterial properties, both peptides act as promoters of the regenerative process of axotomized leech CNS. These data are the first to report the neuronal synthesis of antimicrobial peptides and their participation in the immune response and the regeneration of the CNS. Thus, the leech CNS appears as an excellent model for studying the implication of immune molecules in neural repair. PMID:18606660

  20. Direct Measurement of Pore Dynamics and Leakage Induced by a Model Antimicrobial Peptide in Single Vesicles and Cells.

    Science.gov (United States)

    Burton, Matthew G; Huang, Qi M; Hossain, Mohammed A; Wade, John D; Palombo, Enzo A; Gee, Michelle L; Clayton, Andrew H A

    2016-06-28

    Antimicrobial peptides are promising therapeutic alternatives to counter growing antimicrobial resistance. Their precise mechanism of action remains elusive, however, particularly with respect to live bacterial cells. We investigated the interaction of a fluorescent melittin analogue with single giant unilamellar vesicles, giant multilamellar vesicles, and bilamellar Gram-negative Escherichia coli (E. coli) bacteria. Time-lapse fluorescence lifetime imaging microscopy was employed to determine the population distribution of the fluorescent melittin analogue between pore state and membrane surface state, and simultaneously measure the leakage of entrapped fluorescent species from the vesicle (or bacterium) interior. In giant unilamellar vesicles, leakage from vesicle interior was correlated with an increase in level of pore states, consistent with a stable pore formation mechanism. In giant multilamellar vesicles, vesicle leakage occurred more gradually and did not appear to correlate with increased pore states. Instead pore levels remained at a low steady-state level, which is more in line with coupled equilibria. Finally, in single bacterial cells, significant increases in pore levels were observed over time, which were correlated with only partial loss of cytosolic contents. These observations suggested that pore formation, as opposed to complete dissolution of membrane, was responsible for the leakage of contents in these systems, and that the bacterial membrane has an adaptive capacity that resists peptide attack. We interpret the three distinct pore dynamics regimes in the context of the increasing physical and biological complexity of the membranes. PMID:27281288

  1. Intrathecal application of the antimicrobial peptide CRAMP reduced mortality and neuroinflammation in an experimental model of pneumococcal meningitis.

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    Dörr, Arndt; Kress, Eugenia; Podschun, Rainer; Pufe, Thomas; Tauber, Simone C; Brandenburg, Lars-Ove

    2015-08-01

    Antimicrobial peptides (AP) are important components of the innate immune system. Our previous work revealed a higher mortality rate and up-regulation of proinflammatory gene expression as well as glial cell activation in cathelicidin-related antimicrobial peptide (CRAMP)-deficient mice after bacterial meningitis. However, the influence of CRAMP application on the progression of inflammation and its impact on mortality after bacterial meningitis remains unknown. To assess the effects of continuous CRAMP exposure in the brain, C57BL/6 wildtype mice were given intracerebroventricular infusion of CRAMP to investigate the effects on mortality, glial cell activation and inflammation in a mouse model of pneumococcal meningitis using immunohistochemistry and realtime RT-PCR. Our results revealed a decrease of mortality after CRAMP infusion. The intrathecal CRAMP infusion after pneumococcal meningitis resulted in a decreased mRNA expression of pro-inflammatory cytokines, whereas the immune responses including the expression of pattern recognition receptors and chemokines were increased in bacterial meningitis. Taken together, the results support the important role of CRAMP as part of the innate immune response against pathogens in bacterial CNS infections. The APs may be a promising approach for the development of an adjuvant therapy for bacterial meningitis. PMID:25896094

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

    Science.gov (United States)

    de Lorgeril, Julien; Gueguen, Yannick; Goarant, Cyrille; Goyard, Emmanuel; Mugnier, Chantal; Fievet, Julie; Piquemal, David; Bachère, Evelyne

    2008-07-01

    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 the shrimp, Litopenaeus stylirostris, to circumvent a pathogenic Vibrio penaeicida infection. Additionally, significant differences in some AMP transcript amounts are evidenced between control, non-selected shrimp line and the third generation breeding of shrimp selected for their survival to natural V. penaeicida infections. On the basis of these results, it will now be of great interest to determine if these AMPs are directly involved in the resistance of shrimp to infection or if they only reflect other acquired defence mechanisms which can confer a resistance. PMID:18486974

  3. Human antimicrobial peptide LL-37 inhibits adhesion of Candida albicans by interacting with yeast cell-wall carbohydrates.

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    Pei-Wen Tsai

    Full Text Available Candida albicans is the major fungal pathogen of humans. Fungal adhesion to host cells is the first step of mucosal infiltration. Antimicrobial peptides play important roles in the initial mucosal defense against C. albicans infection. LL-37 is the only member of the human cathelicidin family of antimicrobial peptides and is commonly expressed in various tissues and cells, including epithelial cells of both the oral cavity and urogenital tract. We found that, at sufficiently low concentrations that do not kill the fungus, LL-37 was still able to reduce C. albicans infectivity by inhibiting C. albicans adhesion to plastic surfaces, oral epidermoid OECM-1 cells, and urinary bladders of female BALB/c mice. Moreover, LL-37-treated C. albicans floating cells that did not adhere to the underlying substratum aggregated as a consequence of LL-37 bound to the cell surfaces. According to the results of a competition assay, the inhibitory effects of LL-37 on cell adhesion and aggregation were mediated by its preferential binding to mannan, the main component of the C. albicans cell wall, and partially by its ability to bind chitin or glucan, which underlie the mannan layer. Therefore, targeting of cell-wall carbohydrates by LL-37 provides a new strategy to prevent C. albicans infection, and LL-37 is a useful, new tool to screen for other C. albicans components involved in adhesion.

  4. Salmonella enterica serovar enteritidis antimicrobial peptide resistance genes aid in defense against chicken innate immunity, fecal shedding, and egg deposition.

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    McKelvey, Jessica A; Yang, Ming; Jiang, Yanhua; Zhang, Shuping

    2014-12-01

    Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major etiologic agent of nontyphoid salmonellosis in the United States. S. Enteritidis persistently and silently colonizes the intestinal and reproductive tract of laying hens, resulting in contaminated poultry products. The consumption of contaminated poultry products has been identified as a significant risk factor for human salmonellosis. To understand the mechanisms S. Enteritidis utilizes to colonize and persist in laying hens, we used selective capture of transcribed sequences to identify genes overexpressed in the HD11 chicken macrophage cell line and in primary chicken oviduct epithelial cells. From the 15 genes found to be overexpressed in both cell types, we characterized the antimicrobial peptide resistance (AMPR) genes, virK and ybjX, in vitro and in vivo. In vitro, AMPR genes were required for natural morphology, motility, secretion, defense against detergents such as EDTA and bile salts, and resistance to antimicrobial peptides polymyxin B and avian β-defensins. From this, we inferred the AMPR genes play a role in outer membrane stability and/or modulation. In the intestinal tract, AMPR genes were involved in early intestinal colonization and fecal shedding. In the reproductive tract, virK was required in early colonization whereas a deletion of ybjX caused prolonged ovary colonization and egg deposition. Data from the present study indicate that AMPR genes are differentially utilized in various host environments, which may ultimately assist S. Enteritidis in persistent and silent colonization of chickens. PMID:25267840

  5. Characterization of proteinases from the midgut of Rhipicephalus (Boophilus microplus involved in the generation of antimicrobial peptides

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    Craik Charles S

    2010-07-01

    Full Text Available Abstract Background Hemoglobin is a rich source of biologically active peptides, some of which are potent antimicrobials (hemocidins. A few hemocidins have been purified from the midgut contents of ticks. Nonetheless, how antimicrobials are generated in the tick midgut and their role in immunity is still poorly understood. Here we report, for the first time, the contribution of two midgut proteinases to the generation of hemocidins. Results An aspartic proteinase, designated BmAP, was isolated from the midgut of Rhipicephalus (Boophilus microplus using three chromatographic steps. Reverse transcription-quantitative polymerase chain reaction revealed that BmAP is restricted to the midgut. The other enzyme is a previously characterized midgut cathepsin L-like cysteine proteinase designated BmCL1. Substrate specificities of native BmAP and recombinant BmCL1 were mapped using a synthetic combinatorial peptide library and bovine hemoglobin. BmCL1 preferred substrates containing non-polar residues at P2 subsite and polar residues at P1, whereas BmAP hydrolysed substrates containing non-polar amino acids at P1 and P1'. Conclusions BmAP and BmCL1 generate hemocidins from hemoglobin alpha and beta chains in vitro. We postulate that hemocidins may be important for the control of tick pathogens and midgut flora.

  6. Recombinant Production of Snakin-2 (an Antimicrobial Peptide from Tomato in E. coli and Analysis of Its Bioactivity

    Directory of Open Access Journals (Sweden)

    Vera Herbel

    2015-08-01

    Full Text Available Antimicrobial peptides (AMPs represent a diverse group of biologically active molecules that are part of the innate immune systems of a variety of organisms. Their primary function consists of protecting the host organism against invading microorganisms, including pathogens. AMPs show a broad spectrum of secondary structures, which are essential for antimicrobial activity. In this study, we produced snakin-2 (SN2, a 66-amino-acid-(aa-long AMP from Solanum lycopersicum as a recombinant protein in E. coli. This AMP belongs to the GASA/GAST protein family and possesses a highly conserved 60-aa-long domain with six disulfide bonds in the C-terminus of the peptide. Because of the toxicity of SN2 against its producing E. coli strain, the AMP was attached to an N-terminal fusion protein (thioredoxin A, which was removed after affinity chromatography purification. The total yield of recombinant SN2 was approximately 1 mg/L. The membrane-active SN2 showed a bactericidal and fungicidal bioactivity, which can be explained by perforation of biomembranes of bacteria and fungi.

  7. Purification and in vitro Activity of an Antimicrobial Peptide from Skin of Rana Temporaria Chensinensis, David

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jie; MENG Qing-fan; XU Xue-song; TIAN Xiao-le; JIANG Fu-jia; LI Qing-shan; TENG Li-rong

    2007-01-01

    In this study, an antimicrobial component (RTCI) was purified from the skin of Rana temporaria chensinensis,David. Antimicrobial activities of RTCI against clinical multi-drug resistant bacterial strains, including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureaus, Klebsiella oxytoca, Klebsiella pneumoniae, Enterococcus faecalis, and Proteus mirabilis were measured in vitro by means of minimal inhibitory concentration and time-kill studies.The results indicate that RTCI could inhibit the growth of these bacteria at a proper concentration and suggest that RTCI shows a better antimicrobial activity to Gram-negative bacterial strains than to Gram-positive bacterial strains.

  8. Novel engineered cationic antimicrobial peptides display broad-spectrum activity against Francisella tularensis, Yersinia pestis and Burkholderia pseudomallei.

    Science.gov (United States)

    Abdelbaqi, Suha; Deslouches, Berthony; Steckbeck, Jonathan; Montelaro, Ronald; Reed, Douglas S

    2016-02-01

    Broad-spectrum antimicrobials are needed to effectively treat patients infected in the event of a pandemic or intentional release of a pathogen prior to confirmation of the pathogen's identity. Engineered cationic antimicrobial peptides (eCAPs) display activity against a number of bacterial pathogens including multi-drug-resistant strains. Two lead eCAPs, WLBU2 and WR12, were compared with human cathelicidin (LL-37) against three highly pathogenic bacteria: Francisella tularensis, Yersinia pestis and Burkholderia pseudomallei. Both WLBU2 and WR12 demonstrated bactericidal activity greater than that of LL-37, particularly against F. tularensis and Y. pestis. Only WLBU2 had bactericidal activity against B. pseudomallei. WLBU2, WR12 and LL-37 were all able to inhibit the growth of the three bacteria in vitro. Because these bacteria can be facultative intracellular pathogens, preferentially infecting macrophages and dendritic cells, we evaluated the activity of WLBU2 against F. tularensis in an ex vivo infection model with J774 cells, a mouse macrophage cell line. In that model WLBU2 was able to achieve greater than 50 % killing of F. tularensis at a concentration of 12.5 μM. These data show the therapeutic potential of eCAPs, particularly WLBU2, as a broad-spectrum antimicrobial for treating highly pathogenic bacterial infections. PMID:26673248

  9. Analysis of Healing Effect of Alginate Sulfate Hydrogel Dressing Containing Antimicrobial Peptide on Wound Infection Caused by Methicillin-Resistant Staphylococcus aureus

    Science.gov (United States)

    Babavalian, Hamid; Latifi, Ali Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin; Mohammadi, Sajjad; Moosazadeh Moghaddam, Mehrdad

    2015-01-01

    Background: Wound infections caused by methicillin-resistant Staphylococcus aureus are a health problem worldwide; therefore, it is necessary to develop new antimicrobial compounds. Considering broad-spectrum antimicrobial activity and low probability of drug resistance to peptides, applications these peptides are being studied extensively. Objectives: In this study, to control drug release over time, an alginate sulfate-based hydrogel impregnated with the CM11 peptide as the antimicrobial agent was developed, and its healing effects were tested on skin infections caused by methicillin-resistant S. aureus strains in a mouse model. Materials and Methods: Minimum inhibitory and minimum bactericidal concentrations of the CM11 peptide and alginate hydrogel in combination with the peptide were determined. Forty mice were divided into 4 groups: 1 group as a negative control (without treatment; however, 5 mice received hydrogel dressing without peptide), 1 group as a positive control (2% mupirocin treatment), and 2 groups as test groups. To establish skin infection, 200 μL of bacterial suspension with 3 × 108 CFU/mL concentration was subcutaneously injected in the scapular region of the mice. On the basis of the in vitro minimal bactericidal concentration of the alginate hydrogel containing peptide for 15 clinical isolates, hydrogel containing 128 mg/L of peptide was used for wound dressing over an 8-day period. Results: The highest and lowest numbers of wounds were observed on day 2 in the negative and positive control groups, respectively. During the 8-day period, the positive control and hydrogel containing peptide treatment groups showed similar levels of wound healing. Conclusions: This study showed that compared to standard drug treatment, treatment with hydrogel containing peptide had substantial antibacterial effects on S. aureus wound infections in mice. PMID:26487923

  10. Destabilization of α-Helical Structure in Solution Improves Bactericidal Activity of Antimicrobial Peptides: Opposite Effects on Bacterial and Viral Targets

    OpenAIRE

    Ulaeto, David O.; Morris, Christopher J.; Fox, Marc A.; Gumbleton, Mark; Beck, Konrad

    2016-01-01

    We have previously examined the mechanism of antimicrobial peptides on the outer membrane of vaccinia virus. We show here that the formulation of peptides LL37 and magainin-2B amide in polysorbate 20 (Tween 20) results in greater reductions in virus titer than formulation without detergent, and the effect is replicated by substitution of polysorbate 20 with high-ionic-strength buffer. In contrast, formulation with polysorbate 20 or high-ionic-strength buffer has the opposite effect on bacteri...

  11. Ancient Antimicrobial Peptides Kill Antibiotic-Resistant Pathogens: Australian Mammals Provide New Options

    OpenAIRE

    Wang, Jianghui; Wong, Emily S.W.; Whitley, Jane C; Jian LI; Stringer, Jessica M.; Short, Kirsty R.; Renfree, Marilyn B; Belov, Katherine; Cocks, Benjamin G.

    2011-01-01

    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 a...

  12. Antibiotic activity and structural analysis of the scorpion-derived antimicrobial peptide IsCT and its analogs.

    Science.gov (United States)

    Lee, Kyungik; Shin, Song Yub; Kim, Kyoungho; Lim, Shin Saeng; Hahm, Kyung-Soo; Kim, Yangmee

    2004-10-15

    IsCT is a non-cell-selective antimicrobial peptide isolated from the scorpion Opisthacanthus madagascariensis that has potent cytolytic activity against both mammalian and bacterial cells. To investigate the structure-activity relationships of IsCT and to design novel peptide antibiotics with bacterial cell selectivity, we synthesized several analogs of IsCT and determined their three-dimensional structures in solution by 2D-NMR spectroscopy. IsCT has a linear alpha-helical structure from Gly3 to Phe13, and [K7]-IsCT has a linear alpha-helical structure from Leu2 to Phe13. [K7, P8, K11]-IsCT, which has a bend in its middle region, exhibited the highest antibacterial activity without hemolytic activity, suggesting that its proline-induced bend is an important determinant of this selectivity. Tryptophan fluorescence showed that the high selectivity of [K7, P8, K11]-IsCT toward bacterial cells is closely correlated with its highly selective interaction with negatively charged phospholipids. Its potent activity against antibiotic-resistant bacteria suggests that [K7, P8, K11]-IsCT may serve as a promising lead candidate in the development of new peptide antibiotics. PMID:15369808

  13. High-resolution NMR structure of the antimicrobial peptide protegrin-2 in the presence of DPC micelles

    Energy Technology Data Exchange (ETDEWEB)

    Usachev, K. S., E-mail: k.usachev@kpfu.ru; Efimov, S. V.; Kolosova, O. A.; Filippov, A. V.; Klochkov, V. V. [Kazan Federal University (Russian Federation)

    2015-04-15

    PG-1 adopts a dimeric structure in dodecylphosphocholine (DPC) micelles, and a channel is formed by the association of several dimers but the molecular mechanisms of the membrane damage by non-α-helical peptides are still unknown. The formation of the PG-1 dimer is important for pore formation in the lipid bilayer, since the dimer can be regarded as the primary unit for assembly into the ordered aggregates. It was supposed that only 12 residues (RGGRL-CYCRR-RFCVC-V) are needed to endow protegrin molecules with strong antibacterial activity and that at least four additional residues are needed to add potent antifungal properties. Thus, the 16-residue protegrin (PG-2) represents the minimal structure needed for broad-spectrum antimicrobial activity encompassing bacteria and fungi. As the peptide conformation and peptide-to-membrane binding properties are very sensitive to single amino acid substitutions, the solution structure of PG-2 in solution and in a membrane mimicking environment are crucial. In order to find evidence if the oligomerization state of PG-1 in a lipid environment will be the same or not for another protegrins, we investigate in the present work the PG-2 NMR solution structure in the presence of perdeuterated DPC micelles. The NMR study reported in the present work indicates that PG-2 form a well-defined structure (PDB: 2MUH) composed of a two-stranded antiparallel β-sheet when it binds to DPC micelles.

  14. The intrinsic antimicrobial activity of citric acid-coated manganese ferrite nanoparticles is enhanced after conjugation with the antifungal peptide Cm-p5

    Science.gov (United States)

    Lopez-Abarrategui, Carlos; Figueroa-Espi, Viviana; Lugo-Alvarez, Maria B; Pereira, Caroline D; Garay, Hilda; Barbosa, João ARG; Falcão, Rosana; Jiménez-Hernández, Linnavel; Estévez-Hernández, Osvaldo; Reguera, Edilso; Franco, Octavio L; Dias, Simoni C; Otero-Gonzalez, Anselmo J

    2016-01-01

    Diseases caused by bacterial and fungal pathogens are among the major health problems in the world. Newer antimicrobial therapies based on novel molecules urgently need to be developed, and this includes the antimicrobial peptides. In spite of the potential of antimicrobial peptides, very few of them were able to be successfully developed into therapeutics. The major problems they present are molecule stability, toxicity in host cells, and production costs. A novel strategy to overcome these obstacles is conjugation to nanomaterial preparations. The antimicrobial activity of different types of nanoparticles has been previously demonstrated. Specifically, magnetic nanoparticles have been widely studied in biomedicine due to their physicochemical properties. The citric acid-modified manganese ferrite nanoparticles used in this study were characterized by high-resolution transmission electron microscopy, which confirmed the formation of nanocrystals of approximately 5 nm diameter. These nanoparticles were able to inhibit Candida albicans growth in vitro. The minimal inhibitory concentration was 250 µg/mL. However, the nanoparticles were not capable of inhibiting Gram-negative bacteria (Escherichia coli) or Gram-positive bacteria (Staphylococcus aureus). Finally, an antifungal peptide (Cm-p5) from the sea animal Cenchritis muricatus (Gastropoda: Littorinidae) was conjugated to the modified manganese ferrite nanoparticles. The antifungal activity of the conjugated nanoparticles was higher than their bulk counterparts, showing a minimal inhibitory concentration of 100 µg/mL. This conjugate proved to be nontoxic to a macrophage cell line at concentrations that showed antimicrobial activity. PMID:27563243

  15. Stability and efficacy of synthetic cationic antimicrobial peptides nebulized using high frequency acoustic waves.

    Science.gov (United States)

    Wang, Ying; Rezk, Amgad R; Khara, Jasmeet Singh; Yeo, Leslie Y; Ee, Pui Lai Rachel

    2016-05-01

    Surface acoustic wave (SAW), a nanometer amplitude electroelastic wave generated and propagated on low-loss piezoelectric substrates (such as LiNbO3), is an extremely efficient solid-fluid energy transfer mechanism. The present study explores the use of SAW nebulization as a solution for effective pulmonary peptide delivery. In vitro deposition characteristics of the nebulized peptides were determined using a Next Generation Cascade Impactor. 70% of the peptide-laden aerosols generated were within a size distribution favorable for deep lung distribution. The integrity of the nebulized peptides was found to be retained, as shown via mass spectrometry. The anti-mycobacterial activity of the nebulized peptides was found to be uncompromised compared with their non-nebulized counterparts, as demonstrated by the minimum inhibition concentration and the colony forming inhibition activity. The peptide concentration and volume recoveries for the SAW nebulizer were significantly higher than 90% and found to be insensitive to variation in the peptide sequences. These results demonstrate the potential of the SAW nebulization platform as an effective delivery system of therapeutic peptides through the respiratory tract to the deep lung. PMID:27375820

  16. cgMolluscidin, a novel dibasic residue repeat rich antimicrobial peptide, purified from the gill of the Pacific oyster, Crassostrea gigas.

    Science.gov (United States)

    Seo, Jung-Kil; Lee, Min Jeong; Nam, Bo-Hye; Park, Nam Gyu

    2013-08-01

    A 5.5 kDa antimicrobial peptide consisting of 55 amino acids, cgMolluscidin, was purified from the acidified gill extract of the Pacific oyster, Crassostrea gigas, by ion-exchange and C18 reversed-phase high performance liquid chromatography. By comparing the N-terminal amino acid sequences and the molecular weight of this peptide with those of other known antimicrobial peptides, it has been revealed that this peptide had no homology with any known peptides. cgMolluscidin showed potent antimicrobial activity against both Gram-positive bacteria, including Bacillus subtilis, Micrococcus luteus, and Staphylococcus aureus (minimal effective concentrations [MECs]; 1.3-31.3 μg/mL), and Gram-negative bacteria, including Escherichia coli, Salmonella enterica, and Vibrio parahaemolyticus ([MECs]; 0.4-2.3 μg/mL), without hemolytic activity. However, cgMolluscidin did not show any significant activity against Candida albicans. The deduced amino acid sequence of the cgMolluscidin showed no hit in public protein databases, while the nucleotide sequence had a 99% homology (E value = 0) with only the unknown ESTs sequenced by C. gigas EST project. Tissue distribution of the cgMolluscidin mRNA suggests that it is constitutively expressed as a mature form in a non-tissue-specific manner. The cgMolluscidin mRNA expression level was significantly up-regulated at 12 h (2.8-fold) post injection with Vibrio sp. This peptide is highly basic and contains several dibasic residue repeats including Lysine-Lysine or Lysine-Arginine in the sequence, but may not form an ordered structure. These results suggest that cgMolluscidin might be an oyster-specific novel antimicrobial peptide. PMID:23711469

  17. 杀精抗菌功能抗菌肽的研究进展%Research Progress of the Antimicrobial Peptides with Dualfunctionality of Spermicide and Microbicide

    Institute of Scientific and Technical Information of China (English)

    张尉(综述); 侯丽; 于和鸣(审校)

    2013-01-01

      抗菌肽(antimicrobial peptides)是广泛存在于生物体内的一类抵抗外源性病原微生物致病作用的防御性小分子多肽。抗菌肽拥有巨大的抗菌潜能和广泛的抗菌谱,以及安全、无毒副作用等特点,其中有些抗菌肽还展现了强有力的杀精避孕功能。综述Magainin,Dermaseptins,Nisin和Subtilosin 4种抗菌肽的杀精抗菌功能,为研制具有杀精抗菌双功能的生物制剂提供新的思路和来源。%Antimicrobial peptides are of important components of low-molecular weight peptides to defense organisms invasion. Antimicrobial peptides have many characteristics,such as the big antibacterial potential,broad antibacterial spectrum,safety,and non-toxic. Some of them also have powerful spermicidal and contraceptive potential. This review introduced the difunctionality of spermicide and microbicide of four antimicrobial peptides,including Magainin,Dermaseptins,Nisin and Subtilosin,which could provide us new ideas to develop the biological products with the difunctionality of spermicide and microbicide.

  18. The MprF protein is required for lysinylation of phospholipids in listerial membranes and confers resistance to cationic antimicrobial peptides (CAMPs) on Listeria monocytogenes

    NARCIS (Netherlands)

    Thedieck, Kathrin; Hain, Torsten; Mohamed, Walid; Tindall, Brian J; Nimtz, Manfred; Chakraborty, Trinad; Wehland, Jürgen; Jänsch, Lothar

    2006-01-01

    Pathogenic bacteria have to cope with defence mechanisms mediated by adaptive and innate immunity of the host cells. Cationic antimicrobial peptides (CAMPs) represent one of the most effective components of the host innate immune response. Here we establish the function of Lmo1695, a member of the V

  19. Interaction of a novel antimicrobial peptide isolated from the venom of solitary bee Colletes daviesanus with phospholipid vesicles and Escherichia coli cells

    Czech Academy of Sciences Publication Activity Database

    Čujová, Sabína; Bednárová, Lucie; Slaninová, Jiřina; Straka, J.; Čeřovský, Václav

    2014-01-01

    Roč. 20, č. 11 (2014), s. 885-895. ISSN 1075-2617 Institutional support: RVO:61388963 Keywords : antimicrobial peptides * wild-bee venom * CD spectroscopy * large unilamellar vesicles * membrane permeabilization * electron microscopy Subject RIV: CE - Biochemistry Impact factor: 1.546, year: 2014

  20. 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

  1. Release of Periplasmic Nucleotidase Induced by Human Antimicrobial Peptide in E. coli Causes Accumulation of the Immunomodulator Adenosine.

    Directory of Open Access Journals (Sweden)

    Andreia Bergamo Estrela

    Full Text Available Previous work by our group described that human β-defensin-2 induces accumulation of extracellular adenosine (Ado in E. coli cultures through a non-lytic mechanism causing severe plasmolysis. Here, we investigate the presence of AMP as a direct precursor and the involvement of a bacterial enzyme in the generation of extracellular Ado by treated bacteria. Following hBD-2 treatment, metabolites were quantified in the supernatants using targeted HPLC-MS/MS analysis. Microbial growth was monitored by optical density and cell viability was determined by colony forming units counts. Phosphatase activity was measured using chromogenic substrate pNPP. The results demonstrate that defensin-treated E. coli strain W releases AMP in the extracellular space, where it is converted to Ado by a bacterial soluble factor. An increase in phosphatase activity in the supernatant was observed after peptide treatment, similar to the effect of sucrose-induced osmotic stress, suggesting that the periplasmic 5'nucleotidase (5'-NT is released following the plasmolysis event triggered by the peptide. Ado accumulation was enhanced in the presence of Co2+ ion and inhibited by EDTA, further supporting the involvement of a metallo-phosphatase such as 5'-NT in extracellular AMP conversion into Ado. The comparative analysis of hBD-induced Ado accumulation in different E. coli strains and in Pseudomonas aeruginosa revealed that the response is not correlated to the peptide's effect on cell viability, but indicates it might be dependent on the subcellular distribution of the nucleotidase. Taken together, these data shed light on a yet undescribed mechanism of host-microbial interaction: a human antimicrobial peptide inducing selective release of a bacterial enzyme (E. coli 5'-NT, leading to the formation of a potent immunomodulator metabolite (Ado.

  2. Evaluation of the Antimicrobial Activity of the K9CATH Peptide (38 Amino Acids Against a Mastitis Isolated Strain of Staphylococcus aureus by the Resazurin microtiter Method

    Directory of Open Access Journals (Sweden)

    Albero Barreras-Serrano

    2014-04-01

    Full Text Available The antimicrobial activity of the synthetic peptide K9CATH was determined by the Resazurin microtitre Method (RMM against a strain of S. aureus isolated from a case of mastitis. To the antibiogram this bacteria strain showed to be resistant to Ampicillin, Erythromycin, Cefeprime, Dicloxaciline and Penicillin (10 U, while the MIC obtained for the K9CATH was 5.66 &mug/mL. Unlike the reference broth method, visual reading for MIC determination with the RMM showed to be easier, rapid, inexpensive and more sensitive for antimicrobial peptide screening, based in a color change from blue (not growth to pink (growth. This is the first time that the resazurin method is used to determine the MIC of the 38 aa´s K9CATH peptide against a mastitic isolate of S. aureus.

  3. Composite Membranes of Recombinant Silkworm Antimicrobial Peptide and Poly (L-lactic Acid) (PLLA) for biomedical application.

    Science.gov (United States)

    Li, Zhi; Liu, Xuan; Li, Yi; Lan, Xiqian; Leung, Polly Hangmei; Li, Jiashen; Li, Gang; Xie, Maobin; Han, Yanxia; Lin, Xiaofen

    2016-01-01

    Antimicrobial peptides, produced by innate immune system of hosts in response to invading pathogens, are capable of fighting against a spectrum of bacteria, viruses, fungi, parasites and cancer cells. Here, a recombinant silkworm AMP Bmattacin2 from heterologous expression is studied, indicating a broad spectrum of antibacterial activity and showing selective killing ability towards skin and colon cancer cells over their normal cell counterparts. For the purpose of biomedical application, the electrospinning fabrication technique is employed to load Bmattacin2 into PLLA nanofibrous membrane. In addition to a good compatibility with the normal cells, Bmattacin2 loaded nanofibrous membranes demonstrate instant antibacterial effects and sustained anticancer effects. The cancer cell and bacteria targeting dynamics of recombinant Bmattacin2 are investigated. With these characteristics, PLLA/Bmattacin2 composite membranes have a great potential for developing novel biomedical applications such as cancer therapies and wound healing treatments. PMID:27503270

  4. Conformational analysis by theoretical calculations of distinctin, an antimicrobial peptide isolated from Phyllomedusa distincta

    International Nuclear Information System (INIS)

    Various studies demonstrate that different frog species produce distinct classes of biologically active peptides. These peptides can act as alternative agents against pathogenic bacteria and fungi by membrane permeability. Although studies have recently demonstrated that this process is utterly related to the secondary structure adopted by the peptide (in this case, the α-helical structure) when in contact with the bacterial membrane, the detailed mechanism is still unknown. In this work we describe a conformational analysis of distinctin, a heterodimeric peptide isolated from the skin of Phyllomedusa distincta, an anuran found in the Brazilian Atlantic Forest. The study yielded a stable geometry with a high content of the α-helical structure both in chains 1 and 2 of distinctin, showing strong interaction between them. (author)

  5. Selective Acylation Enhances Membrane Charge Sensitivity of the Antimicrobial Peptide Mastoparan-X

    DEFF Research Database (Denmark)

    Etzerodt, Thomas Povl; Henriksen, Jonas Rosager; Rasmussen, Palle;

    2011-01-01

    The partitioning of the wasp venom peptide mastoparan-X (MPX) into neutral and negatively charged lipid membranes has been compared with two new synthetic analogs of MPX where the Nα-terminal of MPX was acylated with propanoic acid (PA) and octanoic acid (OA). The acylation caused a considerable...... change in the membrane partitioning properties of MPX and it was found that the shorter acylation with PA gave improved affinity and selectivity toward negatively charged membranes, whereas OA decreased the selectivity. Based on these findings, we hypothesize that minor differences in the embedding and...... positioning of the peptide in the membrane caused by either PA or OA acylation play a critical role in the fine-tuning of the effective charge of the peptide and thereby the fine-tuning of the peptide's selectivity between neutral and negatively charged lipid membranes. This finding is unique compared to...

  6. High Therapeutic Index of Factor C Sushi Peptides: Potent Antimicrobials against Pseudomonas aeruginosa

    OpenAIRE

    Yau, Yin Hoe; Ho, Bow; Tan, Nguan Soon; Ng, Miang Lon; Ding, Jeak Ling

    2001-01-01

    Factor C protein isolated from the horseshoe crab, Carcinoscorpius rotundicauda, has endotoxin binding capability. Synthetic peptides of 34 amino acids based on the sequence of two regions of factor C (Sushi 1 and Sushi 3) as well as their corresponding mutants exhibited activities against 30 clinical isolates of Pseudomonas aeruginosa. Collectively, all four peptides demonstrated exceptionally effective bactericidal activity against P. aeruginosa with 90% minimal bactericidal concentrations ...

  7. The effect of the antimicrobial peptide, Dhvar-5, on gentamicin release from a polymethyl methacrylate bone cement.

    Science.gov (United States)

    Faber, C; Hoogendoorn, R J W; Lyaruu, D M; Stallmann, H P; van Marle, J; van Nieuw Amerongen, A; Smit, T H; Wuisman, P I J M

    2005-10-01

    The objective of this study was to investigate the release mechanism and kinetics of the antimicrobial peptide, Dhvar-5, both alone and in combination with gentamicin, from a standard commercial polymethyl methacrylate (PMMA) bone cement. Different amounts of Dhvar-5 were mixed with the bone cement powders of Osteopal and the gentamicin-containing Osteopal G bone cement and their release kinetics from the polymerized cement were investigated. Additionally, the internal structure of the bone cements were analysed by scanning electron microscopy (SEM) of the fracture surfaces. Secondly, porosity was investigated with the mercury intrusion method and related to the observed release profiles. In order to obtain an insight into the mechanical characteristics of the bone cement mixtures, the compressive strength of Osteopal and Osteopal G with Dhvar-5 was also investigated. The total Dhvar-5 release reached 96% in the 100 mg Dhvar-5/g Osteopal cement, whereas total gentamicin release from Osteopal G reached only 18%. Total gentamicin release increased significantly to 67% with the addition of 50mg Dhvar-5/g, but the Dhvar-5 release was not influenced. SEM showed an increase of dissolved gentamicin crystals with the addition of Dhvar-5. The mercury intrusion results suggested an increase of small pores (cements. We therefore conclude that the antimicrobial peptide, Dhvar-5, was released in high amounts from PMMA bone cement. When used together with gentamicin sulphate, Dhvar-5 made the gentamicin crystals accessible for the release medium presumably through increased micro-porosity (< 0.1 microm) resulting in a fourfold increase of gentamicin release. PMID:15878377

  8. Dynamics and orientation of a cationic antimicrobial peptide in two membrane-mimetic systems.

    Science.gov (United States)

    Kosol, Simone; Zangger, Klaus

    2010-04-01

    In order to investigate the functional and structural properties of cationic alpha-helical peptides in two different membranes, we studied the 20-residue peptide maximin H6 in two membrane-mimetic systems by NMR spectroscopy using partially (15)N-labeled peptide and paramagnetic relaxation enhancements. Maximin H6, which is found in skin secretions of frogs of the Bombinae family, attacks gram-negative bacteria and acts haemolytically. While the peptide spontaneously folds into similar structures in both neutral dodecylphosphocholine (DPC) and negatively charged sodium dodecyl sulphate (SDS) micelles, its structure is more flexible in SDS as shown by (15)N relaxation measurements. In addition, it is bound closer to the surface of the micelle and rotated by approximately 70 degrees around its helix axis in the negatively charged membrane surrogate compared to the structure in DPC. This might form the basis for peptide-peptide interactions through a GxxxG motif, which could finally lead to membrane disruption and, thus, preferential attack of negatively charged microbial cell walls. PMID:20045466

  9. 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

  10. Increased Bacterial Load and Expression of Antimicrobial Peptides in Skin of Barrier-Deficient Mice with Reduced Cancer Susceptibility.

    Science.gov (United States)

    Natsuga, Ken; Cipolat, Sara; Watt, Fiona M

    2016-01-01

    Mice lacking three epidermal barrier proteins-envoplakin, periplakin, and involucrin (EPI-/- mice)-have a defective cornified layer, reduced epidermal γδ T cells, and increased dermal CD4(+) T cells. They are also resistant to developing skin tumors. The tumor-protective mechanism involves signaling between Rae-1 expressing keratinocytes and the natural killer group 2D receptor on immune cells, which also plays a role in host defenses against infection. Given the emerging link between bacteria and cancer, we investigated whether EPI-/- mice have an altered skin microbiota. The bacterial phyla were similar in wild-type and EPI-/- skin. However, bacteria were threefold more abundant in EPI-/- skin and penetrated deeper into the epidermis. The major epithelial defense mechanism against bacteria is production of antimicrobial proteins (AMPs). EPI-/- skin exhibited enhanced expression of antimicrobial peptides. However, reducing the bacterial load by antibiotic treatment or breeding mice under specific pathogen-free conditions did not reduce AMP expression or alleviate the abnormalities in T-cell populations. We conclude that the atopic characteristics of EPI-/- skin are a consequence of the defective barrier rather than a response to the increased bacterial load. It is therefore unlikely that the increase in skin microbiota contributes directly to the observed cancer resistance. PMID:26763429

  11. What Goes around Comes around-A Comparative Study of the Influence of Chemical Modifications on the Antimicrobial Properties of Small Cyclic Peptides

    Directory of Open Access Journals (Sweden)

    Margitta Dathe

    2013-09-01

    Full Text Available Tryptophan and arginine-rich cyclic hexapeptides of the type cyclo-RRRWFW combine high antibacterial activity with rapid cell killing kinetics, but show low toxicity in human cell lines. The peptides fulfil the structural requirements for membrane interaction such as high amphipathicity and cationic charge, but membrane permeabilisation, which is the most common mode of action of antimicrobial peptides (AMPs, could not be observed. Our current studies focus on elucidating a putative membrane translocation mechanism whereupon the peptides might interfere with intracellular processes. These investigations require particular analytical tools: fluorescent analogues and peptides bearing appropriate reactive groups were synthesized and characterized in order to be used in confocal laser scanning microscopy and HPLC analysis. We found that minimal changes in both the cationic and hydrophobic domain of the peptides in most cases led to significant reduction of antimicrobial activity and/or changes in the mode of action. However, we were able to identify two modified peptides which exhibited properties similar to those of the cyclic parent hexapeptide and are suitable for subsequent studies on membrane translocation and uptake into bacterial cells.

  12. Development of a formulation lyophilized for the obtention of a antimicrobial peptide Ubiquicidine labelled with 99m Tc

    International Nuclear Information System (INIS)

    The 99m Tc-UBI 29-41 are a labelled fragment of the antimicrobial human peptide Ubiquicidine proposed as a new radiopharmaceutical able to differentiate an infectious process of an inflammatory one through the gamma graphic image. It has been demonstrated that the 99m Tc-UBI 29-41 unite to bacteria in vitro and that accumulates in infection sites in human with minimum captivation in inflammation sites. In this work the development of a pharmaceutical lyophilized formulation is presented for the instantaneous marked one of the UBI 29-41 with 99m Tc. The selection of the components of the formulation settled down by means of the employment of an experimental design of 3 factors with mixed levels, evaluating the effect of the diluent type, concentration of tinny chloride and the reaction volume. The obtained formulations showed to be stable until for 6 months, being obtained complexes of the radiolabelled peptide with radiochemical purity > 95 % in sterile form and apirogen. The developed pharmaceutical form, will facilitate the routinary use of this new radiopharmaceutical in the diverse hospital departments of nuclear medicine. (Author)

  13. Prediction of Antimicrobial Peptides Based on Sequence Alignment and Support Vector Machine-Pairwise Algorithm Utilizing LZ-Complexity

    Directory of Open Access Journals (Sweden)

    Xin Yi Ng

    2015-01-01

    Full Text Available This study concerns an attempt to establish a new method for predicting antimicrobial peptides (AMPs which are important to the immune system. Recently, researchers are interested in designing alternative drugs based on AMPs because they have found that a large number of bacterial strains have become resistant to available antibiotics. However, researchers have encountered obstacles in the AMPs designing process as experiments to extract AMPs from protein sequences are costly and require a long set-up time. Therefore, a computational tool for AMPs prediction is needed to resolve this problem. In this study, an integrated algorithm is newly introduced to predict AMPs by integrating sequence alignment and support vector machine- (SVM- LZ complexity pairwise algorithm. It was observed that, when all sequences in the training set are used, the sensitivity of the proposed algorithm is 95.28% in jackknife test and 87.59% in independent test, while the sensitivity obtained for jackknife test and independent test is 88.74% and 78.70%, respectively, when only the sequences that has less than 70% similarity are used. Applying the proposed algorithm may allow researchers to effectively predict AMPs from unknown protein peptide sequences with higher sensitivity.

  14. 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.

  15. “Specificity Determinants” Improve Therapeutic Indices of Two Antimicrobial Peptides Piscidin 1 and Dermaseptin S4 Against the Gram-negative Pathogens Acinetobacter baumannii and Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Ziqing Jiang

    2014-03-01

    Full Text Available A new class of antimicrobial agents with lower rates of resistance and different targets is urgently needed because of the rapidly increasing resistance to classical antibiotics. Amphipathic cationic α-helical antimicrobial peptides (AMPs represent such a class of compounds. In our previous studies, using a 26-residue de novo designed antimicrobial peptide, we proposed the concept of “specificity determinant(s”: positively charged residue(s in the center of the non-polar face of AMPs that could decrease hemolytic activity/toxicity but increase or maintain the same level of antimicrobial activity to increase dramatically the therapeutic index. In the current study, we used d-enantiomers of two AMPs, Piscidin 1 isolated from fish and dermaseptin S4 isolated from frog. We substituted different positions in the center of the hydrophobic face with one or two lysine residue(s (one or two “specificity determinant(s”. This simple modification not only maintained or improved antimicrobial activity against Gram-negative pathogens Acinetobacter baumannii (11 strains and Pseudomonas aeruginosa (6 strains, but also dramatically decreased hemolytic activity of human red blood cells, as predicted. Therapeutic indices improved by 55-fold and 730-fold for piscidin 1 (I9K and dermaseptin S4 (L7K, A14K, respectively, against A. baumannii. Similarly, the therapeutic indices improved 32-fold and 980-fold for piscidin 1 (I9K and dermaseptin S4 (L7K, A14K, respectively, against P. aeruginosa.

  16. Activity of antimicrobial peptide mimetics in the oral cavity: II. Activity against periopathogenic biofilms and anti-inflammatory activity.

    Science.gov (United States)

    Hua, J; Scott, R W; Diamond, G

    2010-12-01

    Whereas periodontal disease is ultimately of bacterial etiology, from multispecies biofilms of gram-negative anaerobic microorganisms, much of the deleterious effects are caused by the resultant epithelial inflammatory response. Hence, development of a treatment that combines anti-biofilm antibiotic activity with anti-inflammatory activity would be of great utility. Antimicrobial peptides (AMPs) such as defensins are naturally occurring peptides that exhibit broad-spectrum activity as well as a variety of immunomodulatory activities. Furthermore, bacteria do not readily develop resistance to these agents. However, clinical studies have suggested that they do not represent optimal candidates for exogenous therapeutic agents. Small-molecule mimetics of these AMPs exhibit similar activities to the parent peptides, in addition to having low toxicity, high stability and low cost. To determine whether AMP mimetics have the potential for treatment of periodontal disease, we examined the activity of one mimetic, mPE, against biofilm cultures of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Metabolic assays as well as culture and biomass measurement assays demonstrated that mPE exhibits potent activity against biofilm cultures of both species. Furthermore, as little as 2 μg ml(-1) mPE was sufficient to inhibit interleukin-1β-induced secretion of interleukin-8 in both gingival epithelial cells and THP-1 cells. This anti-inflammatory activity is associated with a reduction in activation of nuclear factor-κB, suggesting that mPE can act both as an anti-biofilm agent in an anaerobic environment and as an anti-inflammatory agent in infected tissues. PMID:21040516

  17. Reduced cytotoxicity and enhanced bioactivity of cationic antimicrobial peptides liposomes in cell cultures and 3D epidermis model against HSV.

    Science.gov (United States)

    Ron-Doitch, Sapir; Sawodny, Beate; Kühbacher, Andreas; David, Mirjam M Nordling; Samanta, Ayan; Phopase, Jaywant; Burger-Kentischer, Anke; Griffith, May; Golomb, Gershon; Rupp, Steffen

    2016-05-10

    Cationic antimicrobial peptides (AMPs) are part of the innate immunity, and act against a wide variety of pathogenic microorganisms by perturbation of the microorganism's plasma membrane. Although attractive for clinical applications, these agents suffer from limited stability and activity in vivo, as well as non-specific interaction with host biological membranes, leading to cytotoxic adverse effects. We hypothesized that encapsulation of AMPs within liposomes could result in reduced cytotoxicity, and with enhanced stability as well as bioactivity against herpes simplex virus 1 (HSV-1). We formulated nano-sized liposomal formulations of LL-37 and indolicidin, and their physicochemical properties, cellular uptake, in vitro cytotoxicity and antiviral efficacy have been determined. Lower cytotoxicity of LL-37 liposomes was found in comparison to indolicidin liposomes attributed to the superior physicochemical properties, and to the different degree of interaction with the liposomal membrane. The disc-like shaped LL-37 liposomes (106.8±10.1nm, shelf-life stability of >1year) were taken up more rapidly and to a significantly higher extent than the free peptide by human keratinocyte cell line (HaCaT), remained intact within the cells, followed by release of the active peptide within the cytoplasm and migration of the vesicles' lipids to the plasma membrane. LL-37 liposomes were found significantly less toxic than both the free agent and liposomal indolicidin. In the new 3D epidermis model (immortalized primary keratinocytes) liposomal LL-37 treatment (>20μM), but not free LL-37, efficiently protected the epidermis, inhibiting HSV-1 infection. This positive antiviral effect was obtained with no cytotoxicity even at very high concentrations (400μM). Thus, the antiviral activity of encapsulated LL-37 was significantly improved, expanding its therapeutic window. Liposomal LL-37 appears to be a promising delivery system for HSV therapy. PMID:27012977

  18. Membrane-mediated repulsion between gramicidin pores

    OpenAIRE

    Constantin, Doru

    2015-01-01

    International audience We investigated the X-ray scattering signal of highly aligned multilayers of the zwitterionic lipid 1,2-dilauroyl-sn-glycero-3-phosphatidylcholine containing pores formed by the antimicrobial peptide gramicidin as a function of the peptide/lipid ratio. We are able to obtain information on the structure factor of the pore fluid, which then yields the interaction potential between pores in the plane of the bilayers. Aside from a hard core with a radius close to the geo...

  19. 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

  20. The structure and behavior of the NA-CATH antimicrobial peptide with liposomes.

    Science.gov (United States)

    Du, Haijuan; Samuel, Robin L; Massiah, Michael A; Gillmor, Susan D

    2015-10-01

    Naja atra cathelicidin (NA-CATH) is a 34-amino acid highly cationic peptide identified in Chinese cobras to possess potent toxicity against gram-negative and gram-positive bacteria and low toxicity against host cells. Here, we report the NMR solution structure of the full-length NA-CATH peptide and its interaction with liposomes. The structure shows a well-defined α-helix between residues Phe3 to Lys23, on which one surface is lined by the side-chains of one arginine and 11 lysine residues, while the other side is populated by hydrophobic residues. The last eleven amino acids, which are predominately aromatic and hydrophobic in nature, have no defined structure. NMR data reveal that these residues do not interact with the hydrophobic residues of the helix, indicating that the C-terminal residues have random conformations. Fluorescence requenching experiments, in which liposomes serve as a mimic of the bacterial membranes, result in fluorophore leakage that is consistent with a membrane thinning or transient pore formation mechanism. NMR titration studies of the peptide-liposome interaction reveal that the peptide is in fast exchange with the liposome, consistent with the fluorescent studies. These data indicate that full length NA-CATH possesses a helical segment and unstructured C-terminal tail that disrupts the bilayer to induce leakage and lysing. PMID:26205847

  1. Candida species and antimicrobial peptides from the venom of the eusocial bee Lasioglossum laticeps

    Czech Academy of Sciences Publication Activity Database

    Slaninová, Jiřina; Borovičková, Lenka; Putnová, H.; Fučík, Vladimír; Čeřovský, Václav

    Praha : Institut of Organic Chemistry and Biochemistry ASCR, 2009. s. 59-59. ISBN 978-80-86241-30-2. [Biologically Active Peptides /11./. 22.04.2009-24.04.2009, Praha] Institutional research plan: CEZ:AV0Z40550506 Keywords : C. albicans * C. glabrata * C. krusei * C. parapsilosis Subject RIV: CC - Organic Chemistry

  2. Chiroptical properties of the antimicrobial peptide Lasiocepsin and of its analogs

    Czech Academy of Sciences Publication Activity Database

    Maloň, P.; Pazderková, Markéta; Profant, V.; Baumruk, V.; Bednárová, Lucie

    Vienna : Vienna University of Technology, 2015 - (Lendl, B.; Koch, C.; Kraft, M.; Ofner, J.; Ramer, G.). s. 502-503 ISBN 978-3-200-04205-6. [ICAVS8. International Conference on Advanced Vibrational Spectroscopy /8./. 12.07.2015-17.07.2015, Vienna] Institutional support: RVO:61388963 Keywords : vibrational optical activity * peptide * disulfide Subject RIV: CF - Physical ; Theoretical Chemistry

  3. Starvation- and Stationary-phase-induced resistance to the antimicrobial peptide polymyxin B in Salmonella typhimurium is RpoS (sigma(S)) independent and occurs through both phoP-dependent and -independent pathways.

    OpenAIRE

    McLeod, G I; Spector, M P

    1996-01-01

    A common stress encountered by Salmonella serovars involves exposure to membrane-permeabilizing antimicrobial peptides and proteins such as defensins, cationic antibacterial proteins, and polymyxins. We wanted to determine if starvation induces cross-resistance to the membrane-permeabilizing antimicrobial peptide polymyxin B (PmB). We report here that starved and stationary-phase (Luria-Bertani [LB] medium) cells exhibited ca. 200- to 1,500-fold-higher (cross-)resistance to a 60-min PmB chall...

  4. Structural identification by mass spectrometry of a novel antimicrobial peptide from the venom of the solitary bee Osmia rufa (Hymenoptera: Megachilidae).

    Science.gov (United States)

    Stöcklin, Reto; Favreau, Philippe; Thai, Robert; Pflugfelder, Jochen; Bulet, Philippe; Mebs, Dietrich

    2010-01-01

    The venom from the solitary bee Osmia rufa (Hymenoptera: Megachilidae) was analyzed using mass spectrometry (MS)-based techniques. Sensitive proteomic methods such as on-line LC-ESI-MS and nanoESI-MS analyses revealed more than 50 different compounds with molecular masses ranging from 400 to 4000Da. The major component has a monoisotopic molecular mass of 1924.20Da and its amino acid sequence was elucidated by de novo sequencing using tandem mass spectrometry and Edman degradation. This 17-residue cysteine-free peptide, named osmin, shows some similarities with the mast cell degranulation (MCD) peptide family. Free acid and C-terminally amidated osmins were chemically synthesized and tested for antimicrobial and haemolytic activities. The synthetic C-amidated peptide (native osmin) was found to be about three times more haemolytic than its free acid counterpart, but both peptides are much less lytic than melittin from social bee venom. Preliminary antimicrobial and antifungal tests indicate that both peptides are able to inhibit bacterial and fungal growth at micromolar concentrations. PMID:19109988

  5. Destabilization of α-Helical Structure in Solution Improves Bactericidal Activity of Antimicrobial Peptides: Opposite Effects on Bacterial and Viral Targets.

    Science.gov (United States)

    Ulaeto, David O; Morris, Christopher J; Fox, Marc A; Gumbleton, Mark; Beck, Konrad

    2016-04-01

    We have previously examined the mechanism of antimicrobial peptides on the outer membrane of vaccinia virus. We show here that the formulation of peptides LL37 and magainin-2B amide in polysorbate 20 (Tween 20) results in greater reductions in virus titer than formulation without detergent, and the effect is replicated by substitution of polysorbate 20 with high-ionic-strength buffer. In contrast, formulation with polysorbate 20 or high-ionic-strength buffer has the opposite effect on bactericidal activity of both peptides, resulting in lesser reductions in titer for both Gram-positive and Gram-negative bacteria. Circular dichroism spectroscopy shows that the differential action of polysorbate 20 and salt on the virucidal and bactericidal activities correlates with the α-helical content of peptide secondary structure in solution, suggesting that the virucidal and bactericidal activities are mediated through distinct mechanisms. The correlation of a defined structural feature with differential activity against a host-derived viral membrane and the membranes of both Gram-positive and Gram-negative bacteria suggests that the overall helical content in solution under physiological conditions is an important feature for consideration in the design and development of candidate peptide-based antimicrobial compounds. PMID:26824944

  6. Inducible ASABF-Type Antimicrobial Peptide from the Sponge Suberites domuncula: Microbicidal and Hemolytic Activity in Vitro and Toxic Effect on Molluscs in Vivo

    Directory of Open Access Journals (Sweden)

    Werner E. G. Müller

    2011-10-01

    Full Text Available Since sponges, as typical filter-feeders, are exposed to a high load of attacking prokaryotic and eukaryotic organisms, they are armed with a wide arsenal of antimicrobial/cytostatic low-molecular-weight, non-proteinaceous bioactive compounds. Here we present the first sponge agent belonging to the group of ASABF-type antimicrobial peptides. The ASABF gene was identified and cloned from the demospongeSuberites domuncula. The mature peptide, with a length of 64 aa residues has a predicted pI of 9.24, and comprises the characteristic CSαβ structural motif. Consequently, the S. domuncula ASABF shares high similarity with the nematode ASABFs; it is distantly related to the defensins. The recombinant peptide was found to display besides microbicidal activity, anti-fungal activity. In addition, the peptide lyses human erythrocytes. The expression ofASABF is upregulated after exposure to the apoptosis-inducing agent 2,2'-dipyridyl. During the process of apoptosis of surface tissue of S. domuncula, grazing gastropods (Bittium sp. are attracted by quinolinic acid which is synthesized through the kynurenine pathway by the enzyme 3-hydroxyanthranilate 3,4-dioxygenase (HAD. Finally, the gastropods are repelled from the sponge tissue by the ASABF. It is shown that the effector peptide ASABF is sequentially expressed after the induction of the HAD gene and a caspase, as a central enzyme executing apoptosis.

  7. Structural Characterization of de Novo Designed L5K5W Model Peptide Isomers with Potent Antimicrobial and Varied Hemolytic Activities

    Directory of Open Access Journals (Sweden)

    Sung-Jean Park

    2013-01-01

    Full Text Available In an effort to develop short antimicrobial peptides with simple amino acid compositions, we generated a series of undecapeptide isomers having the L5K5W formula. Amino acid sequences were designed to be perfectly amphipathic when folded into a helical conformation by converging leucines onto one side and lysines onto the other side of the helical axis. The single tryptophans, whose positions were varied in the primary structures, were located commonly at the critical amphipathic interface in the helical wheel projection. Helical conformations and the tryptophanyl environments of the 11 L5K5W peptides were confirmed and characterized by circular dichroism, fluorescence and nuclear magnetic resonance spectroscopy. All of the isomers exhibited a potent, broad-spectrum of antibacterial activity with just a slight variance in individual potency, whereas their hemolytic activities against human erythrocytes were significantly diversified. Interestingly, helical dispositions and fluorescence blue shifts of the peptides in aqueous trifluoroethanol solutions, rather than in detergent micelles, showed a marked linear correlation with their hemolytic potency. These results demonstrate that our de novo design strategy for amphipathic helical model peptides is effective for developing novel antimicrobial peptides and their hemolytic activities can be estimated in correlation with structural parameters.

  8. Antimicrobial peptide from eusocial bee Halictus sexcinctus interacting with model membranes

    Czech Academy of Sciences Publication Activity Database

    Pazderková, Markéta; Kočišová, E.; Pazderka, T.; Souček, P.; Maloň, Petr; Kopecký, V. Jr.; Bednárová, Lucie

    Cluj-Napoca: -, Publishing House Napoca Star - (Nagy-Póra, K.; Chis, V.; Astilean, S.; Cozar, O.). s. 220-220 ISBN 978-973-647-912-0. [EUCMOS 2012. European congress on molecular spectroscopy /31./. 26.08.2012-31.08.2012, Cluj-Napoca] R&D Projects: GA ČR GAP208/10/0376 Institutional research plan: CEZ:AV0Z40550506 Keywords : circular dichroism * FTIR * antibacterial peptides * halictine * liposome Subject RIV: CF - Physical ; Theoretical Chemistry

  9. Lactic acid bacteria and their antimicrobial peptides : Induction,detection,partial characterization, and potential applications

    OpenAIRE

    Abbas Hilmi, Hanan

    2010-01-01

    Bacteriocin-producing lactic acid bacteria and their isolated peptide bacteriocins are of value to control pathogens and spoiling microorganisms in foods and feed. Nisin is the only bacteriocin that is commonly accepted as a food preservative and has a broad spectrum of activity against Gram-positive organisms including spore forming bacteria. In this study nisin induction was studied from two perspectives, induction from inside of the cell and selection of nisin inducible strains with increa...

  10. Overcoming barriers in Pseudomonas aeruginosa lung infections: Engineered nanoparticles for local delivery of a cationic antimicrobial peptide.

    Science.gov (United States)

    d'Angelo, Ivana; Casciaro, Bruno; Miro, Agnese; Quaglia, Fabiana; Mangoni, Maria Luisa; Ungaro, Francesca

    2015-11-01

    Cationic antimicrobial peptides (CAMPs) are very promising in the treatment of multi-drug resistant Pseudomonas aeruginosa lung infections experienced by cystic fibrosis (CF) patients. Nevertheless, there is an urgent need of inhalable formulations able to deliver the intact CAMP in conductive airways and to shield its interactions with airway mucus/bacterial biofilm, thus enhancing CAMP/bacteria interactions. Along these lines, the aim of this work was the design and development of nano-embedded microparticles (NEM) for sustained delivery of CAMPs in the lung. To this purpose, nanoparticles (NPs) made of poly(lactide-co-glycolide) (PLGA) containing a model CAMP, colistin (Col), were produced by emulsion/solvent diffusion technique. Engineering NPs with chitosan (CS) and poly(vinyl alcohol) (PVA) allowed to modulate surface properties and, in so doing, to improve NP transport through artificial CF mucus. In order to achieve a long-term stable dosage form useful for NP inhalation, NPs were spray-dried in different carriers (lactose or mannitol), thus producing NEM. The most promising NEM formulations were selected on the basis of bulk and flow properties, distribution of NPs in the carrier and aerosolization performance upon delivery through a breath-actuated dry powder inhaler. Of note, selected Col-loaded NEM were found to kill P. aeruginosa biofilm and to display a prolonged efficacy in biofilm eradication compared to the free Col. This effect was likely ascribable to the ability of NPs to penetrate into bacterial biofilm, as demonstrated by confocal analysis, and to sustain Col release inside it. Taken all together, our results indicate that adequate engineering of PLGA NPs represents an enticing technological approach to harness novel antimicrobials for P. aeruginosa lung infection, such as CAMPs, especially in CF. PMID:26340361

  11. Tolerance to the antimicrobial peptide colistin in Pseudomonas aeruginosa biofilms is linked to metabolically active cells, and depends on the pmr and mexAB-oprM genes

    DEFF Research Database (Denmark)

    Pamp, Sünje Johanna; Gjermansen, Morten; Johansen, Helle Krogh;

    2008-01-01

    antimicrobial peptide colistin. On the contrary, biofilm cells exhibiting low metabolic activity were killed by colistin. We demonstrate that the subpopulation of metabolically active cells is able to adapt to colistin by inducing a specific adaptation mechanism mediated by the pmr operon, as well as an...... unspecific adaptation mechanism mediated by the mexAB-oprM genes. Mutants defective in either pmr-mediated lipopolysaccharide modification or in mexAB-oprM-mediated antimicrobial efflux were not able to develop a tolerant subpopulation in biofilms. In contrast to the observed pattern of colistin...... physiologically distinct subpopulations by combined antimicrobial treatment with either ciprofloxacin and colistin or tetracycline and colistin almost completely eradicated all biofilm cells....

  12. Synthesis of unusual alpha-amino acids and study of the effect of their incorporation into antimicrobial peptides. Total synthesis of biactive marine natural products and analogues thereof

    OpenAIRE

    El Marrouni El Ghazaoui, Abdellatif

    2012-01-01

    The principle theme of this thesis was the synthesis of bioactive compounds. To this end, this work was focus on two main projects. The first one, which was carried out in the Department of Chemistry of the University of Girona under the supervision of Dr Montserrat Heras, concerned the synthesis of new unnatural amino acids bearing a pyrimidine ring within their side chain for incorporation into the antimicrobial peptide BP100 following a rational design in order to improve its biological pr...

  13. Killing efficacy and anti-biofilm activity of synthetic human cationic antimicrobial peptide cathelicidin hCAP-18/LL37 against urinary tract pathogens

    OpenAIRE

    Safaa Toma Hanna Aka

    2015-01-01

    Objectives: Cathelicidin LL37 represents one of the chemical defence components of bladder epithelial cells that include antimicrobial peptides, which also shown to have an important role in the mucosal immunity of the urinary tract by preventing adhesion of bacteria. This study aimed to determine the killing efficacy of LL37 compared to anti-biofilm activity against Staphylococcus aureus and Escherichia coli. Methods: The 96-flat well microtiter plates were used for evaluation of killing...

  14. Vitamin D nutritional status and vitamin D regulated antimicrobial peptides in serum and pleural fluid of patients with infectious and noninfectious pleural effusions

    OpenAIRE

    Amado, Carlos A.; García-Unzueta, María T; Fariñas, M. Carmen; Santos, Francisca; Ortiz, María; Muñoz-Cacho, Pedro; Amado, José A

    2016-01-01

    Background Vitamin D and vitamin D dependent antimicrobial peptides such as Cathelicidin (LL-37) and β-defensin 2 have an important role in innate and adaptative immunity, but their role in pleural effusions has not been studied before. Methods Serum and pleural fluid samples from 152 patients with pleural effusion were collected, corresponding to 45 transudates and 107 exudates, 51 infectious effusions (14 complicated and 37 non-complicated), 44 congestive heart failure effusions and 38 mali...

  15. Influence of energy balance on the antimicrobial peptides S100A8 and S100A9 in the endometrium of the post-partum dairy cow

    OpenAIRE

    Swangchan-Uthai, Theerawat; Chen, Qiusheng; Kirton, Sally E; Fenwick, Mark A.; Cheng, Zhangrui; Patton, Joe; Fouladi-Nashta, Ali A; Wathes, D Claire

    2013-01-01

    Uterine inflammation occurs after calving in association with extensive endometrial remodelling and bacterial contamination. If the inflammation persists, it leads to reduced fertility. Chronic endometritis is highly prevalent in high-yielding cows that experience negative energy balance (NEB) in early lactation. This study investigated the effect of NEB on the antimicrobial peptides S100A8 and S100A9 in involuting uteri collected 2 weeks post partum. Holstein-Friesian cows (six per treatment...

  16. Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: I. Growth performance, immune function, and antioxidation capacity.

    Science.gov (United States)

    Xiao, H; Wu, M M; Tan, B E; Yin, Y L; Li, T J; Xiao, D F; Li, L

    2013-10-01

    The mycotoxin deoxynivalenol (DON) is a food contaminant that leads to reduced feed intake and reduced BW gain, as well as organ impairment. On the other hand, antimicrobial peptides have been shown to have positive effects on growth performance, nutrient digestibility, and immune function. The purpose of this study was to investigate the protective effects of composite antimicrobial peptides (CAP) on piglets challenged with DON. After a 7-d adaptation period, 28 individually housed 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% CAP (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 ppm DON + 0.4% CAP (DON + CAP). On d 15 and 30 after the initiation of treatment, blood samples were collected for the determination of blood profile. Piglets were monitored for 30 d to assess performance and then were slaughtered to obtain organs for the determination of the relative weight of organs. The results showed that dietary supplementation with DON decreased (P 0.05) on other relative weights of viscera, except the relative weight of the gallbladder, but the diamine oxidase activity in the liver decreased in DON-treated piglets (P 0.05) between the DON + CAP treatment and the other treatments. The DON treatment decreased the numbers of red blood cells and platelets, as well as the serum catalase concentrations, and decreased the serum concentrations of H2O2, maleic dialdehyde, and nitric oxide (P < 0.05). The numbers of platelets and thrombocytocrit, as well as the serum concentrations of catalase, were greater, whereas the maleic dialdehyde concentrations were decreased, in both the CAP and DON + CAP treatments compared with the other treatments (P < 0.05). Compared with the control treatment, DON decreased peripheral lymphocyte proliferation on d 15, whereas supplementation with CAP increased it on d 15 and 30 (P < 0

  17. The potent antimicrobial properties of cell penetrating peptide-conjugated silver nanoparticles with excellent selectivity for Gram-positive bacteria over erythrocytes

    Science.gov (United States)

    Liu, Lihong; Yang, Jun; Xie, Jianping; Luo, Zhentao; Jiang, Jiang; Yang, Yi Yan; Liu, Shaomin

    2013-04-01

    Silver nanoparticles are of great interest for use as antimicrobial agents. Studies aimed at producing potent nano-silver biocides have focused on manipulation of particle size, shape, composition and surface charge. Here, we report the cell penetrating peptide catalyzed formation of antimicrobial silver nanoparticles in N,N-dimethylformamide. The novel nano-composite demonstrated a distinctly enhanced biocidal effect toward bacteria (Gram-positive Bacillus subtilis, Gram-negative Escherichia coli) and pathogenic yeast (Candida albicans), as compared to triangular and extremely small silver nanoparticles. In addition, a satisfactory biocompatibility was verified by a haemolysis test. Our results provide a paradigm in developing strategies that can maximize the silver nanoparticle application potentials while minimizing the toxic effects.Silver nanoparticles are of great interest for use as antimicrobial agents. Studies aimed at producing potent nano-silver biocides have focused on manipulation of particle size, shape, composition and surface charge. Here, we report the cell penetrating peptide catalyzed formation of antimicrobial silver nanoparticles in N,N-dimethylformamide. The novel nano-composite demonstrated a distinctly enhanced biocidal effect toward bacteria (Gram-positive Bacillus subtilis, Gram-negative Escherichia coli) and pathogenic yeast (Candida albicans), as compared to triangular and extremely small silver nanoparticles. In addition, a satisfactory biocompatibility was verified by a haemolysis test. Our results provide a paradigm in developing strategies that can maximize the silver nanoparticle application potentials while minimizing the toxic effects. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr34254a

  18. A Hybrid Cationic Peptide Composed of Human β-Defensin-1 and Humanized θ-Defensin Sequences Exhibits Salt-Resistant Antimicrobial Activity

    Science.gov (United States)

    Nagaraj, Ramakrishnan; Motukupally, Swapna R.

    2014-01-01

    We have designed a hybrid peptide by combining sequences of human β-defensin-1 (HBD-1) and θ-defensin, in an attempt to generate a molecule that combines the diversity in structure and biological activity of two different peptides to yield a promising therapeutic candidate. HBD-1 was chosen as it is a natural defensin of humans that is constitutively expressed, but its antibacterial activity is considerably impaired by elevated ionic strength. θ-Defensins are expressed in human bone marrow as a pseudogene and are homologous to rhesus monkey circular minidefensins. Retrocyclins are synthetic human θ-defensins. The cyclic nature of the θ-defensin peptides makes them salt resistant, nonhemolytic, and virtually noncytotoxic in vitro. However, a nonhuman circular molecule developed for clinical use would be less viable than a linear molecule. In this study, we have fused the C-terminal region of HBD-1 to the nonapeptide sequence of a synthetic retrocyclin. Cyclization was achieved by joining the terminal ends of the hybrid peptide by a disulfide bridge. The hybrid peptide with or without the disulfide bridge exhibited enhanced antimicrobial activity against both Gram-negative and Gram-positive bacteria as well as against fungi, including clinical bacterial isolates from eye infections. The peptide retained activity in the presence of NaCl and serum and was nonhemolytic in vitro. Thus, the hybrid peptide generated holds potential as a new class of antibiotics. PMID:25348533

  19. A hybrid cationic peptide composed of human β-defensin-1 and humanized θ-defensin sequences exhibits salt-resistant antimicrobial activity.

    Science.gov (United States)

    Olli, Sudar; Nagaraj, Ramakrishnan; Motukupally, Swapna R

    2015-01-01

    We have designed a hybrid peptide by combining sequences of human β-defensin-1 (HBD-1) and θ-defensin, in an attempt to generate a molecule that combines the diversity in structure and biological activity of two different peptides to yield a promising therapeutic candidate. HBD-1 was chosen as it is a natural defensin of humans that is constitutively expressed, but its antibacterial activity is considerably impaired by elevated ionic strength. θ-Defensins are expressed in human bone marrow as a pseudogene and are homologous to rhesus monkey circular minidefensins. Retrocyclins are synthetic human θ-defensins. The cyclic nature of the θ-defensin peptides makes them salt resistant, nonhemolytic, and virtually noncytotoxic in vitro. However, a nonhuman circular molecule developed for clinical use would be less viable than a linear molecule. In this study, we have fused the C-terminal region of HBD-1 to the nonapeptide sequence of a synthetic retrocyclin. Cyclization was achieved by joining the terminal ends of the hybrid peptide by a disulfide bridge. The hybrid peptide with or without the disulfide bridge exhibited enhanced antimicrobial activity against both Gram-negative and Gram-positive bacteria as well as against fungi, including clinical bacterial isolates from eye infections. The peptide retained activity in the presence of NaCl and serum and was nonhemolytic in vitro. Thus, the hybrid peptide generated holds potential as a new class of antibiotics. PMID:25348533

  20. Novel Antimicrobial Peptides EeCentrocins 1, 2 and EeStrongylocin 2 from the Edible Sea Urchin Echinus esculentus Have 6-Br-Trp Post-Translational Modifications.

    Science.gov (United States)

    Solstad, Runar Gjerp; Li, Chun; Isaksson, Johan; Johansen, Jostein; Svenson, Johan; Stensvåg, Klara; Haug, Tor

    2016-01-01

    The global problem of microbial resistance to antibiotics has resulted in an urgent need to develop new antimicrobial agents. Natural antimicrobial peptides are considered promising candidates for drug development. Echinoderms, which rely on innate immunity factors in the defence against harmful microorganisms, are sources of novel antimicrobial peptides. This study aimed to isolate and characterise antimicrobial peptides from the Edible sea urchin Echinus esculentus. Using bioassay-guided purification and cDNA cloning, three antimicrobial peptides were characterised from the haemocytes of the sea urchin; two heterodimeric peptides and a cysteine-rich peptide. The peptides were named EeCentrocin 1 and 2 and EeStrongylocin 2, respectively, due to their apparent homology to the published centrocins and strongylocins isolated from the green sea urchin Strongylocentrotus droebachiensis. The two centrocin-like peptides EeCentrocin 1 and 2 are intramolecularly connected via a disulphide bond to form a heterodimeric structure, containing a cationic heavy chain of 30 and 32 amino acids and a light chain of 13 amino acids. Additionally, the light chain of EeCentrocin 2 seems to be N-terminally blocked by a pyroglutamic acid residue. The heavy chains of EeCentrocins 1 and 2 were synthesised and shown to be responsible for the antimicrobial activity of the natural peptides. EeStrongylocin 2 contains 6 cysteines engaged in 3 disulphide bonds. A fourth peptide (Ee4635) was also discovered but not fully characterised. Using mass spectrometric and NMR analyses, EeCentrocins 1 and 2, EeStrongylocin 2 and Ee4635 were all shown to contain post-translationally brominated Trp residues in the 6 position of the indole ring. PMID:27007817

  1. Novel Antimicrobial Peptides EeCentrocins 1, 2 and EeStrongylocin 2 from the Edible Sea Urchin Echinus esculentus Have 6-Br-Trp Post-Translational Modifications

    Science.gov (United States)

    Solstad, Runar Gjerp; Li, Chun; Isaksson, Johan; Johansen, Jostein; Svenson, Johan; Stensvåg, Klara; Haug, Tor

    2016-01-01

    The global problem of microbial resistance to antibiotics has resulted in an urgent need to develop new antimicrobial agents. Natural antimicrobial peptides are considered promising candidates for drug development. Echinoderms, which rely on innate immunity factors in the defence against harmful microorganisms, are sources of novel antimicrobial peptides. This study aimed to isolate and characterise antimicrobial peptides from the Edible sea urchin Echinus esculentus. Using bioassay-guided purification and cDNA cloning, three antimicrobial peptides were characterised from the haemocytes of the sea urchin; two heterodimeric peptides and a cysteine-rich peptide. The peptides were named EeCentrocin 1 and 2 and EeStrongylocin 2, respectively, due to their apparent homology to the published centrocins and strongylocins isolated from the green sea urchin Strongylocentrotus droebachiensis. The two centrocin-like peptides EeCentrocin 1 and 2 are intramolecularly connected via a disulphide bond to form a heterodimeric structure, containing a cationic heavy chain of 30 and 32 amino acids and a light chain of 13 amino acids. Additionally, the light chain of EeCentrocin 2 seems to be N-terminally blocked by a pyroglutamic acid residue. The heavy chains of EeCentrocins 1 and 2 were synthesised and shown to be responsible for the antimicrobial activity of the natural peptides. EeStrongylocin 2 contains 6 cysteines engaged in 3 disulphide bonds. A fourth peptide (Ee4635) was also discovered but not fully characterised. Using mass spectrometric and NMR analyses, EeCentrocins 1 and 2, EeStrongylocin 2 and Ee4635 were all shown to contain post-translationally brominated Trp residues in the 6 position of the indole ring. PMID:27007817

  2. ISOLATION OF THE ANTIMICROBIAL CYCLIC PEPTIDE SUBTILOSIN A FROM A GUT-ASSOCIATED BACILLUS SUBTILIS STRAIN

    Directory of Open Access Journals (Sweden)

    Ghislain Schyns

    2013-01-01

    Full Text Available The endospore-forming Bacillus subtilis has been used as probiotics over the last 50 years. However, little is known on how Bacillus spp act in the gut compared to other well-characterized probiotics such as lactic acid bacteria. It is believed that the competitive exclusion of pathogens results from different mode of action notably the production of antimicrobial compounds such as bacteriocins. Here, we report the characterization of the unexpected ability of a gut-associated B. subtilis BSP1 to synthetize the cyclic bacteriocin subtilosin A at high level. Our findings suggest that the BSP1 phenotype could be related, at least in part, to a subsequent increased expression level of the subtilosin A biosynthetic gene cluster sbo-alb in response to a higher activity of the stationery and sporulation master regulator Spo0A.

  3. Proteus mirabilis ZapA Metalloprotease Degrades a Broad Spectrum of Substrates, Including Antimicrobial Peptides

    OpenAIRE

    Belas, Robert; Manos, Jim; Suvanasuthi, Rooge

    2004-01-01

    The 54-kDa extracellular metalloprotease ZapA is an important virulence factor of uropathogenic Proteus mirabilis. While ZapA has the ability to degrade host immunoglobulins (Igs), the dramatic attenuation of virulence in ZapA mutants suggests that this enzyme may have a broader spectrum of activity. This hypothesis was tested by in vitro assays with purified ZapA and an array of purified protein or peptide substrates. The data reveal that many proteins found in the urinary tract are substrat...

  4. Modeling Interactions between Multicomponent Vesicles and Antimicrobial Peptide-Inspired Nanoparticles.

    Science.gov (United States)

    Chu, Xiaolei; Aydin, Fikret; Dutt, Meenakshi

    2016-08-23

    We examine the interaction between peptide-inspired nanoparticles, or nanopins, and multicomponent vesicles using the dissipative particle dynamics simulation technique. We study the role of nanopin architecture and cholesterol concentration on the binding of the nanopins to the lipid bilayer, their insertion, and postembedding self-organization. We find the insertion to be triggered by enthalpically unfavorable interactions between the hydrophilic solvent and the lipophilic components of the nanopins. The nanopins are observed to form aggregates in solution, insert into the bilayer, and disassemble into the individual nanopins following the insertion process. We examine factors that influence the orientation of the nanopins in the host vesicle. We report the length of the hydrophilic segment of the nanopins to regulate their orientation within the clusters before the embedding process and in the bilayer, after the postinsertion disassembly of the aggregates. The orientation angle distribution for a given nanopin architecture is found to be driven by energy minimization. In addition, higher concentration of cholesterol is observed to constrain the orientation of the nanopins. We also report thermal fluctuations to induce transverse diffusion of nanopins with specific architectures. The incidence of transverse diffusion is observed to decrease with the concentration of cholesterol. Our results can provide guidelines for designing peptide-inspired nanoparticles or macromolecules that can interface with living cells to serve as sensors for applications in medicine, sustainability, and energy. PMID:27434532

  5. Interplay between bladder microbiota and urinary antimicrobial peptides: mechanisms for human urinary tract infection risk and symptom severity.

    Directory of Open Access Journals (Sweden)

    Vanessa Nienhouse

    Full Text Available Resident bacterial communities (microbiota and host antimicrobial peptides (AMPs are both essential components of normal host innate immune responses that limit infection and pathogen induced inflammation. However, their interdependence has not been investigated in the context of urinary tract infection (UTI susceptibility. Here, we explored the interrelationship between the urinary microbiota and host AMP responses as mechanisms for UTI risk. Using prospectively collected day of surgery (DOS urine specimens from female pelvic floor surgery participants, we report that the relative abundance and/or frequency of specific urinary microbiota distinguished between participants who did or did not develop a post-operative UTI. Furthermore, UTI risk significantly correlated with both specific urinary microbiota and β-defensin AMP levels. Finally, urinary AMP hydrophobicity and protease activity were greater in participants who developed UTI, and correlated positively with both UTI risk and pelvic floor symptoms. These data demonstrate an interdependency between the urinary microbiota, AMP responses and symptoms, and identify a potential mechanism for UTI risk. Assessment of bacterial microbiota and host innate immune AMP responses in parallel may identify increased risk of UTI in certain populations.

  6. Expression and Significance of the HIP/PAP and RegIIIγ Antimicrobial Peptides during Mammalian Urinary Tract Infection.

    Science.gov (United States)

    Spencer, John David; Jackson, Ashley R; Li, Birong; Ching, Christina B; Vonau, Martin; Easterling, Robert S; Schwaderer, Andrew L; McHugh, Kirk M; Becknell, Brian

    2015-01-01

    Recent evidence indicates that antimicrobial peptides (AMPs) serve key roles in defending the urinary tract against invading uropathogens. To date, the individual contribution of AMPs to urinary tract host defense is not well defined. In this study, we identified Regenerating islet-derived 3 gamma (RegIIIγ) as the most transcriptionally up-regulated AMP in murine bladder transcriptomes following uropathogenic Escherichia coli (UPEC) infection. We confirmed induction of RegIIIγ mRNA during cystitis and pyelonephritis by quantitative RT-PCR. Immunoblotting demonstrates increased bladder and urinary RegIIIγ protein levels following UPEC infection. Immunostaining localizes RegIIIγ protein to urothelial cells of infected bladders and kidneys. Human patients with UTI have increased urine concentrations of the orthologous Hepatocarcinoma-Intestine-Pancreas / Pancreatitis Associated Protein (HIP/PAP) compared to healthy controls. Recombinant RegIIIγ protein does not demonstrate bactericidal activity toward UPEC in vitro, but does kill Staphylococcus saprophyticus in a dose-dependent manner. Kidney and bladder tissue from RegIIIγ knockout mice and wild-type mice contain comparable bacterial burden following UPEC and Gram-positive UTI. Our results demonstrate that RegIIIγ and HIP/PAP expression is induced during human and murine UTI. However, their specific function in the urinary tract remains uncertain. PMID:26658437

  7. Expression and Significance of the HIP/PAP and RegIIIγ Antimicrobial Peptides during Mammalian Urinary Tract Infection.

    Directory of Open Access Journals (Sweden)

    John David Spencer

    Full Text Available Recent evidence indicates that antimicrobial peptides (AMPs serve key roles in defending the urinary tract against invading uropathogens. To date, the individual contribution of AMPs to urinary tract host defense is not well defined. In this study, we identified Regenerating islet-derived 3 gamma (RegIIIγ as the most transcriptionally up-regulated AMP in murine bladder transcriptomes following uropathogenic Escherichia coli (UPEC infection. We confirmed induction of RegIIIγ mRNA during cystitis and pyelonephritis by quantitative RT-PCR. Immunoblotting demonstrates increased bladder and urinary RegIIIγ protein levels following UPEC infection. Immunostaining localizes RegIIIγ protein to urothelial cells of infected bladders and kidneys. Human patients with UTI have increased urine concentrations of the orthologous Hepatocarcinoma-Intestine-Pancreas / Pancreatitis Associated Protein (HIP/PAP compared to healthy controls. Recombinant RegIIIγ protein does not demonstrate bactericidal activity toward UPEC in vitro, but does kill Staphylococcus saprophyticus in a dose-dependent manner. Kidney and bladder tissue from RegIIIγ knockout mice and wild-type mice contain comparable bacterial burden following UPEC and Gram-positive UTI. Our results demonstrate that RegIIIγ and HIP/PAP expression is induced during human and murine UTI. However, their specific function in the urinary tract remains uncertain.

  8. Pediocin-like antimicrobial peptides (class IIa bacteriocins) and their immunity proteins: biosynthesis, structure, and mode of action.

    Science.gov (United States)

    Fimland, Gunnar; Johnsen, Line; Dalhus, Bjørn; Nissen-Meyer, Jon

    2005-11-01

    Pediocin-like antimicrobial peptides (AMPs) form a group of lactic acid bacteria produced, cationic membrane-permeabilizing peptides with 37 to 48 residues. Upon exposure to membrane-mimicking entities, their hydrophilic, cationic, and highly conserved N-terminal region forms a three-stranded antiparallel beta-sheet supported by a conserved disulfide bridge. This N-terminal beta-sheet region is followed by a central amphiphilic alpha-helix and this in most (if not all) of these peptides is followed by a rather extended C-terminal tail that folds back onto the central alpha-helix, thereby creating a hairpin-like structure in the C-terminal half. There is a flexible hinge between the beta-sheet N-terminal region and the hairpin C-terminal region and one thus obtains two domains that may move relative to each other. The cationic N-terminal beta-sheet domain mediates binding of the pediocin-like AMPs to the target-cell surface through electrostatic interactions, while the more hydrophobic and amphiphilic C-terminal hairpin domain penetrates into the hydrophobic part of the target-cell membrane, thereby mediating leakage through the membrane. The hinge provides the structural flexibility that enables the C-terminal hairpin domain to dip into the hydrophobic part of the membrane. Despite extensive sequence similarities, these AMPs differ markedly in their target-cell specificity, and results obtained with hybrid AMPs indicate that the membrane-penetrating hairpin-like C-terminal domain is the major specificity determinant. Bacteria that produce pediocin-like AMPs also produce a 11-kDa cognate immunity protein that protects the producer. The immunity proteins are well-structured, 4-helix bundle cytosolic proteins. They show a high degree of specificity in that they largely recognize and confer immunity only to their cognate AMP and in some cases to a few AMPs that are closely related to their cognate AMP. The C-terminal half of the immunity proteins contains a domain that

  9. The production of recombinant cationic α-helical antimicrobial peptides in plant cells induces the formation of protein bodies derived from the endoplasmic reticulum.

    Science.gov (United States)

    Company, Nuri; Nadal, Anna; La Paz, José-Luis; Martínez, Sílvia; Rasche, Stefan; Schillberg, Stefan; Montesinos, Emilio; Pla, Maria

    2014-01-01

    Synthetic linear antimicrobial peptides with cationic α-helical structures, such as BP100, are valuable as novel therapeutics and preservatives. However, they tend to be toxic when expressed at high levels as recombinant peptides in plants, and they can be difficult to detect and isolate from complex plant tissues because they are strongly cationic and display low extinction coefficient and extremely limited immunogenicity. We therefore expressed BP100 with a C-terminal tag which preserved its antimicrobial activity and demonstrated significant accumulation in plant cells. We used a fluorescent tag to trace BP100 following transiently expression in Nicotiana benthamiana leaves and showed that it accumulated in large vesicles derived from the endoplasmic reticulum (ER) along with typical ER luminal proteins. Interestingly, the formation of these vesicles was induced by BP100. Similar vesicles formed in stably transformed Arabidopsis thaliana seedlings, but the recombinant peptide was toxic to the host during latter developmental stages. This was avoided by selecting active BP100 derivatives based on their low haemolytic activity even though the selected peptides remained toxic to plant cells when applied exogenously at high doses. Using this strategy, we generated transgenic rice lines producing active BP100 derivatives with a yield of up to 0.5% total soluble protein. PMID:24102775

  10. Antimicrobial Peptide from the Wild Bee Hylaeus signatus Venom and Its Analogues: Structure-Activity Study and Synergistic Effect with Antibiotics.

    Science.gov (United States)

    Nešuta, Ondřej; Hexnerová, Rozálie; Buděšínský, Miloš; Slaninová, Jiřina; Bednárová, Lucie; Hadravová, Romana; Straka, Jakub; Veverka, Václav; Čeřovský, Václav

    2016-04-22

    Venoms of hymenopteran insects have attracted considerable interest as a source of cationic antimicrobial peptides (AMPs). In the venom of the solitary bee Hylaeus signatus (Hymenoptera: Colletidae), we identified a new hexadecapeptide of sequence Gly-Ile-Met-Ser-Ser-Leu-Met-Lys-Lys-Leu-Ala-Ala-His-Ile-Ala-Lys-NH2. Named HYL, it belongs to the category of α-helical amphipathic AMPs. HYL exhibited weak antimicrobial activity against several strains of pathogenic bacteria and moderate activity against Candida albicans, but its hemolytic activity against human red blood cells was low. We prepared a set of HYL analogues to evaluate the effects of structural modifications on its biological activity and to increase its potency against pathogenic bacteria. This produced several analogues exhibiting significantly greater activity compared to HYL against strains of both Staphylococcus aureus and Pseudomonas aeruginosa even as their hemolytic activity remained low. Studying synergism of HYL peptides and conventional antibiotics showed the peptides act synergistically and preferentially in combination with rifampicin. Fluorescent dye propidium iodide uptake showed the tested peptides were able to facilitate entrance of antibiotics into the cytoplasm by permeabilization of the outer and inner bacterial cell membrane of P. aeruginosa. Transmission electron microscopy revealed that treatment of P. aeruginosa with one of the HYL analogues caused total disintegration of bacterial cells. NMR spectroscopy was used to elucidate the structure-activity relationship for the effect of amino acid residue substitution in HYL. PMID:26998557

  11. Facile expression and purification of the antimicrobial peptide histatin 1 with a cleavable self-aggregating tag (cSAT) in Escherichia coli.

    Science.gov (United States)

    Xing, Lei; Xu, Wanghui; Zhou, Bihong; Chen, Yilu; Lin, Zhanglin

    2013-04-01

    Human histatin 1 (Hst1), a member of the histatin family, possesses antimicrobial properties. In this study, we applied a previously developed cleavable self-aggregating tag (cSAT) for the expression and purification of histatin 1 to demonstrate its utility for peptide expression and purification. The tag consists of a self-cleavable intein and a self-assembling peptide ELK16 (I-ELK16). First, an active insoluble aggregate of the recombinant histatin 1-Mxe GyrA intein-ELK16 (Hst1-I-ELK16) fusion protein was produced with a yield of 28.9 μg/mg wet cell pellet. The thiol reagent dithiothreitol (DTT) was then used to induce the intein-mediated cleavage and peptide release into the soluble fraction with a yield of 2.06 μg/mg wet cell pellet and a purity of 70%. The peptide was further purified by high performance liquid chromatography. These results were comparable to the yield and purity achieved when the more conventional glutathione transferase (GST) tag was used. The antimicrobial activities of this recombinant histatin 1 were confirmed against three Candida strains. This cSAT technique offers considerable advantages in terms of its simplicity and speed, eliminating the need for an exogenous protease, and reducing the number of chromatography purification steps. This technique should also be useful for the expression and purification of other AMPs. PMID:23403143

  12. The application of antimicrobial peptides from eukaryotic souses in foods%真核来源的抗菌肽及其在食品中的应用

    Institute of Scientific and Technical Information of China (English)

    国华

    2014-01-01

    Antimicrobial peptides are a class of peptides produced by biological defense systems which role is to fight against exogenous pathogens. These peptides are heat stable with rather broad spectra of inhibition, and they have promising application prospects in whole food line"from farm to table". This review provides an overview of the features of antimicrobial peptides from eukaryotic souses and their applications in different foods.%抗菌肽是生物防御系统产生的一类对抗外源病原体的多肽,具有抑菌谱广,热稳定性好等特点,在“从农场到餐桌”的整个食物链中有广阔的应用前景。介绍了真核来源抗菌肽的生物学特性及在不同食品中的应用,并对抗菌肽的应用前景进行了展望。

  13. 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

  14. Conditions affecting the re-alignment of the antimicrobial peptide PGLa in membranes as monitored by solid state 2H-NMR.

    Science.gov (United States)

    Tremouilhac, Pierre; Strandberg, Erik; Wadhwani, Parvesh; Ulrich, Anne S

    2006-09-01

    The cationic antimicrobial peptide PGLa is electrostatically attracted to bacterial membranes, binds as an amphiphilic alpha-helix, and is thus able to permeabilize the lipid bilayer. Using solid state (2)H-NMR of non-perturbing Ala-d(3) labels on the peptide, we have characterized the helix alignment under a range of different conditions. Even at a very high peptide-to-lipid ratio (1:20) and in the presence of negatively charged lipids, there was no indication of a toroidal wormhole structure. Instead, PGLa re-aligns from a surface-bound S-state to an obliquely tilted T-state, which is presumably dimeric. An intermediate structure half-way between the S- and T-state was observed in fully hydrated multilamellar DMPC vesicles at 1:50, suggesting a fast exchange between the two states on the time scale of >50 kHz. We demonstrate that this equilibrium is shifted from the S- towards the T-state either upon (i) increasing the peptide concentration, (ii) adding negatively charged DMPG, or (iii) decreasing the level of hydration. The threshold concentration for re-alignment in DMPC is found to be between 1:200 and 1:100 in oriented samples at 96% humidity. In fully hydrated multilamellar DMPC vesicles, it shifts to an effective peptide-to-lipid ratio of 1:50 as some peptides are able to escape into the bulk water phase. PMID:16716250

  15. 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.

  16. Expression of a novel antimicrobial peptide Penaeidin4-1 in creeping bentgrass (Agrostis stolonifera L. enhances plant fungal disease resistance.

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    Man Zhou

    Full Text Available BACKGROUND: Turfgrass species are agriculturally and economically important perennial crops. Turfgrass species are highly susceptible to a wide range of fungal pathogens. Dollar spot and brown patch, two important diseases caused by fungal pathogens Sclerotinia homoecarpa and Rhizoctonia solani, respectively, are among the most severe turfgrass diseases. Currently, turf fungal disease control mainly relies on fungicide treatments, which raises many concerns for human health and the environment. Antimicrobial peptides found in various organisms play an important role in innate immune response. METHODOLOGY/PRINCIPAL FINDINGS: The antimicrobial peptide - Penaeidin4-1 (Pen4-1 from the shrimp, Litopenaeus setiferus has been reported to possess in vitro antifungal and antibacterial activities against various economically important fungal and bacterial pathogens. In this study, we have studied the feasibility of using this novel peptide for engineering enhanced disease resistance into creeping bentgrass plants (Agrostis stolonifera L., cv. Penn A-4. Two DNA constructs were prepared containing either the coding sequence of a single peptide, Pen4-1 or the DNA sequence coding for the transit signal peptide of the secreted tobacco AP24 protein translationally fused to the Pen4-1 coding sequence. A maize ubiquitin promoter was used in both constructs to drive gene expression. Transgenic turfgrass plants containing different DNA constructs were generated by Agrobacterium-mediated transformation and analyzed for transgene insertion and expression. In replicated in vitro and in vivo experiments under controlled environments, transgenic plants exhibited significantly enhanced resistance to dollar spot and brown patch, the two major fungal diseases in turfgrass. The targeting of Pen4-1 to endoplasmic reticulum by the transit peptide of AP24 protein did not significantly impact disease resistance in transgenic plants. CONCLUSION/SIGNIFICANCE: Our results

  17. Long-term-stable ether-lipid vs conventional ester-lipid bicelles in oriented solid-state NMR: altered structural information in studies of antimicrobial peptides.

    Science.gov (United States)

    Bertelsen, Kresten; Vad, Brian; Nielsen, Erik H; Hansen, Sara K; Skrydstrup, Troels; Otzen, Daniel E; Vosegaard, Thomas; Nielsen, Niels Chr

    2011-03-01

    Recently, ether lipids have been introduced as long-term stable alternatives to the more natural, albeit easier degradable, ester lipids in the preparation of oriented lipid bilayers and bicelles for oriented-sample solid-state NMR spectroscopy. Here we report that ether lipids such as the frequently used 14-O-PC (1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine) may induce significant changes in the structure and dynamics, including altered interaction between peptides and lipids relative to what is observed with the more conventionally used DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) bilayers. Such effects are demonstrated for the antimicrobial peptide novicidin, for which 2D separate-local-field NMR and circular dichroism experiments reveal significant structural/conformational differences for the peptide in the two different lipid systems. Likewise, we observe altered secondary structure and different temperature-dependent membrane anchoring for the antimicrobial peptide alamethicin depending on whether the peptide is reconstituted into ester or ether lipids. Such observations are not particularly surprising considering the significant difference of the lipids in the phosphorus headgroup and they may provide important new insight into the delicate peptide-membrane interactions in the systems studied. In contrast, these observations reinforce the need to carefully consider potential structural changes in addition to long-term stability prior to the selection of membrane environment of membrane proteins in the analysis of their structure and dynamics. In more general terms, the results underscore the necessity in structural biology to address both the protein and its environments in studies relating structure to function. PMID:21309516

  18. Investigating the effects of L- to D-amino acid substitution and deamidation on the activity and membrane interactions of antimicrobial peptide anoplin.

    Science.gov (United States)

    Won, Amy; Khan, Mourin; Gustin, Sorin; Akpawu, Akuvi; Seebun, Deeptee; Avis, Tyler J; Leung, Bonnie O; Hitchcock, Adam P; Ianoul, Anatoli

    2011-06-01

    Isolated from the venom sac of solitary spider wasp, Anoplius samariensis, anoplin is the smallest linear α-helical antimicrobial peptide found naturally with broad spectrum activity against both Gram-positive and Gram-negative bacteria, and little hemolytic activity toward human erythrocytes. Deamidation was found to decrease the peptide's antibacterial properties. In the present work, interactions of amidated (Ano-NH2) and deamidated (Ano-OH) forms of anoplin as well as Ano-NH2 composed of all D-amino acids (D-Ano-NH2) with model cell membranes were investigated by means of Langmuir Blodgett (LB) technique, atomic force microscopy (AFM), X-ray photoemission electron microscopy (X-PEEM) and carboxyfluorescein leakage assay in order to gain a better understanding of the effect of these peptide modifications on membrane binding and lytic properties. According to LB, all three peptides form stable monolayers at the air/water interface with Ano-NH2 occupying a slightly greater area per molecule than Ano-OH. All three forms of the peptide interact preferentially with anionic 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DPPG), rather than zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid monolayer. Peptides form nanoscale clusters in zwitterionic but not in anionic monolayers. Finally, membrane lytic activity of all derivatives was found to depend strongly on membrane composition and lipid/peptide ratio. The results suggest that amidated forms of peptides are likely to possess higher membrane binding affinity due to the increased charge. PMID:21078293

  19. Peptidoglycan recognition protein-S5 functions as a negative regulator of the antimicrobial peptide pathway in the silkworm, Bombyx mori.

    Science.gov (United States)

    Chen, Kangkang; Zhou, Lin; Chen, Feng; Peng, Yachun; Lu, Zhiqiang

    2016-08-01

    Prophenoloxidase (proPO), immune deficiency (IMD), and Toll are the major signaling pathways leading to melanization and antimicrobial peptide production in insect hemolymph. Peptidoglycan recognition proteins (PGRPs) act as receptors and negative regulators in these pathways, and some PGRPs exhibit antimicrobial activity. Previously, we demonstrated that silkworm PGRP-S5 recognizes peptidoglycans (PGs) and triggers activation of the proPO pathway. It also acts as a bactericide, via its amidase activity (Chen et al., 2014). Here, we generated a C177S site-mutated silkworm PGRP-S5 protein that lacked amidase activity but retained its PG-binding capacity. Functional studies showed that the mutation caused loss of its receptor function for activation of the proPO pathway, suggesting that processing of PG by PGRP-S5 is necessary for formation of the pathway initiation complex. Further, we found that PGRP-S5 negatively regulates antimicrobial peptides generation in an amidase-dependent manner, likely through the IMD pathway. Thus, silkworm PGRP-S5 acts as a sensor, a modulator, and an effector in the silkworm humoral immune system. PMID:27012996

  20. Comment on Repulsive Casimir Forces

    CERN Document Server

    Iannuzzi, D

    2003-01-01

    A recent theoretical calculation shows that the Casimir force between two parallel plates can be repulsive for plates with nontrivial magnetic properties (O. Kenneth et al., Phys. Rev. Lett. 89, 033001 (2002)). According to the authors, the effect may be observed with known materials, such as ferrites and garnets, and it might be possible to engineer micro- or nanoelectromechanical systems (MEMS or NEMS) that could take advantage of a short range repulsive force. Here we show that on the contrary the Casimir force between two parallel plates in vacuum at micron and submicron distance is always attractive.