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Sample records for antimicrobial peptide ll-37

  1. Antimicrobial peptide LL-37 participates in the transcriptional regulation of melanoma cells

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    Muñoz, Mindy; Craske, Madeleine; Severino, Patricia; de Lima, Thais Martins; Labhart, Paul; Chammas, Roger; Velasco, Irineu Tadeu; Machado, Marcel Cerqueira César; Egan, Brian; Nakaya, Helder I; Pinheiro da Silva, Fabiano

    2016-01-01

    Antimicrobial peptides are an ancient family of molecules that emerged millions of years ago and have been strongly conserved during the evolutionary process of living organisms. Recently, our group described that the human antimicrobial peptide LL-37 migrates to the nucleus, raising the possibility that LL-37 could directly modulate transcription under certain conditions. Here, we showed evidence that LL-37 binds to gene promoter regions, and LL-37 gene silencing changed the transcriptional program of melanoma A375 cells genes associated with histone, metabolism, cellular stress, ubiquitination and mitochondria. PMID:27994673

  2. OmpA Binding Mediates the Effect of Antimicrobial Peptide LL-37 on Acinetobacter baumannii.

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    Ming-Feng Lin

    Full Text Available Multidrug-resistant Acinetobacter baumannii has recently emerged as an important pathogen in nosocomial infection; thus, effective antimicrobial regimens are urgently needed. Human antimicrobial peptides (AMPs exhibit multiple functions and antimicrobial activities against bacteria and fungi and are proposed to be potential adjuvant therapeutic agents. This study examined the effect of the human cathelicidin-derived AMP LL-37 on A. baumannii and revealed the underlying mode of action. We found that LL-37 killed A. baumannii efficiently and reduced cell motility and adhesion. The bacteria-killing effect of LL-37 on A. baumannii was more efficient compared to other AMPs, including human ß-defensin 3 (hBD3 and histatin 5 (Hst5. Both flow cytometric analysis and immunofluorescence staining showed that LL-37 bound to A. baumannii cells. Moreover, far-western analysis demonstrated that LL-37 could bind to the A. baumannii OmpA (AbOmpA protein. An ELISA assay indicated that biotin-labelled LL-37 (BA-LL37 bound to the AbOmpA74-84 peptide in a dose-dependent manner. Using BA-LL37 as a probe, the ~38 kDa OmpA signal was detected in the wild type but the ompA deletion strain did not show the protein, thereby validating the interaction. Finally, we found that the ompA deletion mutant was more sensitive to LL-37 and decreased cell adhesion by 32% compared to the wild type. However, ompA deletion mutant showed a greatly reduced adhesion defect after LL-37 treatment compared to the wild strain. Taken together, this study provides evidence that LL-37 affects A. baumannii through OmpA binding.

  3. SP-LL-37, human antimicrobial peptide, enhances disease resistance in transgenic rice

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    Cho, Yong Gu; Nou, Ill Sup; Huq, Md. Amdadul; Nogoy, Franz Marielle; Kang, Kwon-Kyoo

    2017-01-01

    Human LL-37 is a multifunctional antimicrobial peptide of cathelicidin family. It has been shown in recent studies that it can serve as a host’s defense against influenza A virus. We now demonstrate in this study how signal peptide LL-37 (SP-LL-37) can be used in rice resistance against bacterial leaf blight and blast. We synthesized LL-37 peptide and subcloned in a recombinant pPZP vector with pGD1 as promoter. SP-LL-37 was introduced into rice plants by Agrobacterium mediated transformation. Stable expression of SP-LL-37 in transgenic rice plants was confirmed by RT-PCR and ELISA analyses. Subcellular localization of SP-LL-37-GFP fusion protein showed evidently in intercellular space. Our data on testing for resistance to bacterial leaf blight and blast revealed that the transgenic lines are highly resistant compared to its wildtype. Our results suggest that LL-37 can be further explored to improve wide-spectrum resistance to biotic stress in rice. PMID:28282452

  4. Boswellic acids target the human immune system-modulating antimicrobial peptide LL-37.

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    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.

  5. Salivary concentration of the antimicrobial peptide LL-37 in patients with oral lichen planus

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    Sotiria Davidopoulou

    2014-12-01

    Full Text Available Background: The antimicrobial peptide LL-37 is a significant molecule of innate immunity and recent studies indicate that it plays an important role in maintaining oral health. Yet limited knowledge exists on its role in oral diseases and oral lichen planus (OLP in particular. Objective: The study aimed to examine: 1 the salivary concentration of LL-37 in patients with OLP and healthy subjects, 2 the relation between the type (reticular or erosive and size of OLP lesions and LL-37 concentration, and 3 the effect of the therapeutic modalities on LL-37 levels. Design: The salivary peptide concentration in samples from 20 patients and 30 healthy subjects at the same age range was determined by ELISA. Results: Despite the wide variation in peptide concentration found in both groups, the healthy subjects exhibited significantly lower levels than patients. Patients with the erosive form had significantly higher peptide concentrations than patients with the reticular form. Systemic treatment with corticosteroids resulted in a significant decrease of the salivary peptide concentration, while other treatment modalities, such as administration of vitamins A and E or local application of corticosteroids had no effect. Improved clinical appearance of the lesions was followed by a decrease in the salivary LL-37 level. Conclusions: Salivary concentration of LL-37 correlates to the manifestation of mucosa lesions in OLP patients, the highest levels being observed in the most severe cases. This increase in peptide levels may protect against lesion infection and promote a quick wound healing.

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

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    Man Hou

    2013-09-01

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

  7. Novel role of the antimicrobial peptide LL-37 in the protection of neutrophil extracellular traps against degradation by bacterial nucleases

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    Neumann, Ariane; Völlger, Lena; Berends, Evelien T.M.; Molhoek, E. Margo; Stapels, Daphne A.C.; Midon, Marika; Friães, Ana; Pingoud, Alfred; Rooijakkers, Suzan H. M.; Richard L Gallo; Mörgelin, Matthias; Nizet, Victor; Naim, Hassan Y; von Köckritz-Blickwede, Maren

    2014-01-01

    Neutrophil extracellular traps (NETs) have been described as a fundamental innate immune defense mechanism. These NETs consist of a nuclear DNA backbone associated with different antimicrobial peptides (AMPs), which are able to engulf and kill pathogens. The AMP LL-37, a member of the cathelicidin family, is highly present in NETs. However, the function of LL-37 within the NETs is still unknown, since LL-37 loses its antimicrobial activity when bound to DNA in the NETs.

  8. The human cathelicidin antimicrobial peptide LL-37 and mimics are potential anticancer drugs

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    Kengo eKuroda

    2015-06-01

    Full Text Available Antimicrobial peptides (AMPs play a critical role in innate host defense against microbial pathogens in many organisms. The human cathelicidin LL-37 has a net positive charge and is amphiphilic, and can eliminate pathogenic microbes directly via electrostatic attraction toward negatively charged bacterial membranes. A number of studies have shown that LL-37 participates in various host immune systems, such as inflammatory responses and tissue repair, in addition to its antibacterial properties. Moreover, recent evidence suggests that it is also involved in the regulation of cancer. Indeed, previous studies have suggested that human LL-37 is involved in carcinogenesis via multiple reporters such as FPR2 (FPRL1, EGFR, and ERBb2, although LL-37 and its fragments and analogues also show anticancer effects in various cancer cell lines. This discrepancy can be attributed to peptide-based factors, host membrane-based factors, and signal regulation. Here, we describe the association between AMPs and cancer with a focus on anticancer peptide functions and selectivity in an effort to understand potential therapeutic implications.

  9. 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.

  10. Endotoxin, capsule, and bacterial attachment contribute to Neisseria meningitidis resistance to the human antimicrobial peptide LL-37.

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    Jones, Allison; Geörg, Miriam; Maudsdotter, Lisa; Jonsson, Ann-Beth

    2009-06-01

    Pathogenic bacteria have evolved numerous mechanisms to evade the human immune system and have developed widespread resistance to traditional antibiotics. We studied the human pathogen Neisseria meningitidis and present evidence of novel mechanisms of resistance to the human antimicrobial peptide LL-37. We found that bacteria attached to host epithelial cells are resistant to 10 microM LL-37 whereas bacteria in solution or attached to plastic are killed, indicating that the cell microenvironment protects bacteria. The bacterial endotoxin lipooligosaccharide and the polysaccharide capsule contribute to LL-37 resistance, probably by preventing LL-37 from reaching the bacterial membrane, as more LL-37 reaches the bacterial membrane on both lipooligosaccharide-deficient and capsule-deficient mutants whereas both mutants are also more susceptible to LL-37 killing than the wild-type strain. N. meningitidis bacteria respond to sublethal doses of LL-37 and upregulate two of their capsule genes, siaC and siaD, which further results in upregulation of capsule biosynthesis.

  11. LL-37抗菌肽及其与牙周病的关系%Antimicrobial peptide LL-37 and its relationship between periodontal disease

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    苏瑞英; 陈珊珊

    2012-01-01

    Periodontal disease is a chronic inflammatory disease that leads to destruction of the periodontium. The abnormal innate immune defense and outcome of periodontal disease is closely related. Cathelicidin is one of endogenous peptide, hCAP-18 and LL-37 is the only member of the cathelicidin family known to exist in human. The former is regarded as an inactive precursor, and the latter is the active mature form. In this review, we emphasize on the hCAP-18, the function of LL-37 and its relationship between periodontal disease.%牙周病是一种微生物感染导致的牙周组织炎症破坏性疾病,先天性免疫防御功能正常与否与牙周炎的发展转归息息相关.组织蛋白酶抑制素cathelicidin 是一种内源性抗菌肽,人源阳离子抗菌肽(hCAP)-18和LL-37 是迄今发现的唯一的cathelicidin 家族成员,而前者是其前体形式,后者则是其有活性的成熟形式.本文就hCAP-18和LL-37,LL-37的功能,LL-37与牙周病的关系等研究进展作一综述.

  12. Plasma Antimicrobial Peptide LL-37 Level Is Inversely Associated with HDL Cholesterol Level in Patients with Type 2 Diabetes Mellitus

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    Shu Meguro

    2014-01-01

    Full Text Available Introduction. Relation between atherosclerosis and innate immunity has attracted attention. As the antimicrobial peptide, LL-37, could have an important role in atherosclerosis, we supposed that there could be a meaningful association of plasma LL-37 level with risk factors for cardiovascular disease in subjects with type 2 diabetes mellitus. Materials and Methods. We evaluated plasma LL-37 level and other clinical markers in Japanese subjects with type 2 diabetes mellitus (n=133, 115 men and 18 women; age 64.7±11.5 years; HbA1c 8.1±1.6%. Plasma level of LL-37 was measured by ELISA. Results. Mean plasma LL-37 level was 71.2±22.3 ng/mL. Plasma LL-37 level showed significant correlations with HDL cholesterol (r=−0.450, P<0.01, triglyceride (r=0.445, P<0.01, and high sensitive C-reactive protein (r=0.316, P<0.01 but no significant correlation with age, body mass index, HbA1c, estimated glomerular filtration rate, 25-hydroxyvitamin D, or vitamin D binding protein. Multiple linear regression analysis showed significant correlations of plasma LL-37 level with HDL cholesterol (β=−0.411, P<0.01 and high sensitive C-reactive protein (β=0.193, P<0.05. Conclusion. Plasma LL-37 level was positively correlated with inflammatory markers and negatively correlated with HDL cholesterol in patients with type 2 diabetes mellitus.

  13. Membrane Core-Specific Antimicrobial Action of Cathelicidin LL-37 Peptide Switches Between Pore and Nanofibre Formation

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    Shahmiri, Mahdi; Enciso, Marta; Adda, Christopher G.; Smith, Brian J.; Perugini, Matthew A.; Mechler, Adam

    2016-11-01

    Membrane-disrupting antimicrobial peptides provide broad-spectrum defence against localized bacterial invasion in a range of hosts including humans. The most generally held consensus is that targeting to pathogens is based on interactions with the head groups of membrane lipids. Here we show that the action of LL-37, a human antimicrobial peptide switches the mode of action based on the structure of the alkyl chains, and not the head groups of the membrane forming lipids. We demonstrate that LL-37 exhibits two distinct interaction pathways: pore formation in bilayers of unsaturated phospholipids and membrane modulation with saturated phospholipids. Uniquely, the membrane modulation yields helical-rich fibrous peptide-lipid superstructures. Our results point at alternative design strategies for peptide antimicrobials.

  14. Vitamin D and the human antimicrobial peptide LL-37 enhance group a streptococcus resistance to killing by human cells.

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    Love, John F; Tran-Winkler, Hien J; Wessels, Michael R

    2012-10-23

    The CsrRS two-component regulatory system of group A Streptococcus (GAS; Streptococcus pyogenes) responds to subinhibitory concentrations of the human antimicrobial peptide LL-37. LL-37 signaling through CsrRS results in upregulation of genes that direct synthesis of virulence factors, including the hyaluronic acid capsule and streptolysin O (SLO). Here, we demonstrate that a consequence of this response is augmented GAS resistance to killing by human oropharyngeal keratinocytes, neutrophils, and macrophages. LL-37-induced upregulation of SLO and hyaluronic acid capsule significantly reduced internalization of GAS by keratinocytes and phagocytic killing by neutrophils and macrophages. Because vitamin D induces LL-37 production by macrophages, we tested its effect on macrophage killing of GAS. In contrast to the reported enhancement of macrophage function in relation to other pathogens, treatment of macrophages with 1α,25-dihydroxy-vitamin D3 paradoxically reduced the ability of macrophages to control GAS infection. These observations demonstrate that LL-37 signals through CsrRS to induce a virulence phenotype in GAS characterized by heightened resistance to ingestion and killing by both epithelial cells and phagocytes. By inducing LL-37 production in macrophages, vitamin D may contribute to this paradoxical exacerbation of GAS infection. IMPORTANCE It remains poorly understood why group A Streptococcus (GAS) causes asymptomatic colonization or localized throat inflammation in most individuals but rarely progresses to invasive infection. The human antimicrobial peptide LL-37, which is produced as part of the innate immune response to GAS infection, signals through the GAS CsrRS two-component regulatory system to upregulate expression of multiple virulence factors. This study reports that two CsrRS-regulated GAS virulence factors-streptolysin O and the hyaluronic acid capsule-are critical in LL-37-induced resistance of GAS to killing by human throat epithelial cells

  15. Antimicrobial peptide LL-37 promotes antigen-specific immune responses in mice by enhancing Th17-skewed mucosal and systemic immunities.

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    Kim, Sae-Hae; Yang, In-Young; Kim, Ju; Lee, Kyung-Yeol; Jang, Yong-Suk

    2015-05-01

    The human antimicrobial peptide LL-37 is known to have chemotactic and modulatory activities on various cells including monocytes, T cells, and epithelial cells. Given that LL-37 enhances chemotactic attraction and modulates the activity of DCs, it is conceivable that it might play a role as an immune adjuvant by skewing the immune environment toward immunostimulatory conditions. In this study, we characterized the mucosal adjuvant activity of LL-37 using model and pathogenic Ags. When LL-37-conjugated Ag was administered orally to mice, a tolerogenic Peyer's patch environment was altered to cell populations containing IL-6-secreting CD11c(+), CD11c(+) CD70(+), and Th17 cells capable of evoking a subsequent LL-37-conjugated Ag-specific immune response in both systemic and mucosal immune compartments. In addition, we showed presentation of formyl peptide receptor, an LL-37 receptor, on M cells, which may aid the initiation of an LL-37-mediated enhanced immune response through targeting and transcytosis of the conjugated Ag. Based on our findings, we conclude that LL-37 has potential as an oral mucosal adjuvant, not only by enhancing the delivery of LL-37-conjugated Ag to M cells, but also by triggering T-cell-mediated Ag-specific immune responses through modulation of the mucosal immune environment.

  16. Expressions of Antimicrobial Peptides LL-37, Human Beta Defensin-2 and-3 in the Lesions of Cutaneous Tuberculosis and Tuberculids

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    Zheng Zhao; Zhang-Lei Mu; Xi-Wan Liu; Xiao-Jing Liu; Jun Jia; Lin Cai; Jian-Zhong Zhang

    2016-01-01

    Background:Antimicrobial peptides,including cathelicidin LL-37,human beta defensin (HBD)-2,and HBD-3,are important elements of the innate immune response and involved in modulation of the adaptive immunity,and they also play an important role in cutaneous defense against Mycobacterium tuberculosis.Methods:The fresh skin tissues and paraffin-embedded biopsy samples from three cutaneous tuberculosis,two tuberculids,and ten healthy individuals were collected.The expressions of LL-37,HBD-2,and HBD-3 mRNA in the lesions of three cutaneous tuberculosis and two tuberculids were detected by quantitative real-time polymerase chain reaction;the protein expressions were detected by immunohistochemistry and Western blotting methods.Results:The expressions of LL-37 mRNA and protein in the lesions of cutaneous tuberculosis and tuberculids were similar to that of normal skin.The expression of HBD-2 mRNA had an increasing trend in the lesions of cutaneous tuberculosis and tuberculids compared with that of normal skin;however,the expression of HBD-2 protein in the lesions of cutaneous tuberculosis had a decreasing trend compared with that of normal skin,and the expression of HBD-2 protein in the lesions of tuberculids was similar to that of normal skin.The expressions of HBD-3 mRNA and protein in lesions of cutaneous tuberculosis and tuberculids were similar to that of normal skin.Conclusions:Our study indicated that the expression of HBD-2 and HBD-3 mRNA and protein in lesions of cutaneous tuberculosis may be not consistent with that oftuberculids.However,an inherent limitation of the present study was that the sample size was small,and the roles and regulation mechanisms ofLL-37,HBD-2,and HBD-3 in cutaneous tuberculosis and tuberculids need to be further investigated.

  17. Lipopolysaccharide Phosphorylation by the WaaY Kinase Affects the Susceptibility of Escherichia coli to the Human Antimicrobial Peptide LL-37.

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    Bociek, Karol; Ferluga, Sara; Mardirossian, Mario; Benincasa, Monica; Tossi, Alessandro; Gennaro, Renato; Scocchi, Marco

    2015-08-07

    The human cathelicidin LL-37 is a multifunctional host defense peptide with immunomodulatory and antimicrobial roles. It kills bacteria primarily by altering membrane barrier properties, although the exact sequence of events leading to cell lysis has not yet been completely elucidated. Random insertion mutagenesis allowed isolation of Escherichia coli mutants with altered susceptibility to LL-37, pointing to factors potentially relevant to its activity. Among these, inactivation of the waaY gene, encoding a kinase responsible for heptose II phosphorylation in the LPS inner core, leads to a phenotype with decreased susceptibility to LL-37, stemming from a reduced amount of peptide binding to the surface of the cells, and a diminished capacity to lyse membranes. This points to a specific role of the LPS inner core in guiding LL-37 to the surface of Gram-negative bacteria. Although electrostatic interactions are clearly relevant, the susceptibility of the waaY mutant to other cationic helical cathelicidins was unaffected, indicating that particular structural features or LL-37 play a role in this interaction.

  18. Lipopolysaccharide Phosphorylation by the WaaY Kinase Affects the Susceptibility of Escherichia coli to the Human Antimicrobial Peptide LL-37*

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    Bociek, Karol; Ferluga, Sara; Mardirossian, Mario; Benincasa, Monica; Tossi, Alessandro; Gennaro, Renato; Scocchi, Marco

    2015-01-01

    The human cathelicidin LL-37 is a multifunctional host defense peptide with immunomodulatory and antimicrobial roles. It kills bacteria primarily by altering membrane barrier properties, although the exact sequence of events leading to cell lysis has not yet been completely elucidated. Random insertion mutagenesis allowed isolation of Escherichia coli mutants with altered susceptibility to LL-37, pointing to factors potentially relevant to its activity. Among these, inactivation of the waaY gene, encoding a kinase responsible for heptose II phosphorylation in the LPS inner core, leads to a phenotype with decreased susceptibility to LL-37, stemming from a reduced amount of peptide binding to the surface of the cells, and a diminished capacity to lyse membranes. This points to a specific role of the LPS inner core in guiding LL-37 to the surface of Gram-negative bacteria. Although electrostatic interactions are clearly relevant, the susceptibility of the waaY mutant to other cationic helical cathelicidins was unaffected, indicating that particular structural features or LL-37 play a role in this interaction. PMID:26100635

  19. 抗菌肽LL37在银屑病发病机制中的研究现状%Antimicrobial peptides LL37 in the pathogenesis of psoriasis

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    张翠; 刘彦群; 魏志平

    2012-01-01

    银屑病是一种常见的慢性炎症性皮肤病,与自身反应性T细胞的局部活化及表皮角质形成细胞的异常增殖分化密切相关.银屑病患者皮损中含有大量免疫活性物质,包括多种细胞因子、趋化因子以及抗菌肽LL37等.正常情况下,细胞凋亡产生的少量DNA/RNA可被自身降解,并不引起炎症反应,但角质形成细胞的过度增殖活化,可在皮损局部产生大量自体DNA及RNA.LL37可以破坏机体对自身DNA/RNA的天然免疫耐受,并与之结合形成免疫复合物.该复合物运送至浆细胞样树突细胞早期内体单元中,在Toll样受体的介导下,浆细胞样树突细胞产生大量干扰素-α,而干扰素-α是银屑病中的关键性炎症因子,可以导致银屑病的发病与持续.%Psoriasis is a common chronic inflammatory disease of the skin,which is closely associated with the local activation of autoimmune T cells followed by an abnormal differentiation/proliferation of epidermal keratinocytes.There are lots of immunologically active materials in psoriatic lesions,including various cytokines,chemotactic factors,antimicrobial peptides LL37,and so on.Normally,the quantity of DNA/RNA produced by cell apoptosis is small,which can be broken down by the cells themselves,and can not induce inflammatory reaction.However,abnormally activated and highly proliferative keratinocytes can produce a large quantity of self-DNA/RNA in local lesions.LL37 can break the innate tolerance of organisms to selfDNA/RNA,by binding to the DNA/RNA to form aggregated and condensed structures (immune complexes) which are delivered to early endocytic compartments in plasmacytoid dendritic cells (pDCs).Under stimulation of Tolllike receptors,pDCs can produce abundant interferon α,a key inflammatory factor which can cause the occurrence and development of psoriasis.

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

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

    2013-11-14

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

  1. Factor H-binding protein is important for meningococcal survival in human whole blood and serum and in the presence of the antimicrobial peptide LL-37.

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    Seib, K L; Serruto, D; Oriente, F; Delany, I; Adu-Bobie, J; Veggi, D; Aricò, B; Rappuoli, R; Pizza, M

    2009-01-01

    Factor H-binding protein (fHBP; GNA1870) is one of the antigens of the recombinant vaccine against serogroup B Neisseria meningitidis, which has been developed using reverse vaccinology and is the basis of a meningococcal B vaccine entering phase III clinical trials. Binding of factor H (fH), an inhibitor of the complement alternative pathway, to fHBP enables N. meningitidis to evade killing by the innate immune system. All fHBP null mutant strains analyzed were sensitive to killing in ex vivo human whole blood and serum models of meningococcal bacteremia with respect to the isogenic wild-type strains. The fHBP mutant strains of MC58 and BZ83 (high fHBP expressors) survived in human blood and serum for less than 60 min (decrease of >2 log(10) CFU), while NZ98/254 (intermediate fHBP expressor) and 67/00 (low fHBP expressor) showed decreases of >1 log(10) CFU after 60 to 120 min of incubation. In addition, fHBP is important for survival in the presence of the antimicrobial peptide LL-37 (decrease of >3 log(10) CFU after 2 h of incubation), most likely due to electrostatic interactions between fHBP and the cationic LL-37 molecule. Hence, the expression of fHBP by N. meningitidis strains is important for survival in human blood and human serum and in the presence of LL-37, even at low levels. The functional significance of fHBP in mediating resistance to the human immune response, in addition to its widespread distribution and its ability to induce bactericidal antibodies, indicates that it is an important component of the serogroup B meningococcal vaccine.

  2. PLGA nanoparticles loaded with host defense peptide LL37 promote wound healing.

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    Chereddy, Kiran Kumar; Her, Charles-Henry; Comune, Michela; Moia, Claudia; Lopes, Alessandra; Porporato, Paolo E; Vanacker, Julie; Lam, Martin C; Steinstraesser, Lars; Sonveaux, Pierre; Zhu, Huijun; Ferreira, Lino S; Vandermeulen, Gaëlle; Préat, Véronique

    2014-11-28

    Wound treatment remains one of the most prevalent and economically burdensome healthcare issues in the world. Poly (lactic-co-glycolic acid) (PLGA) supplies lactate that accelerates neovascularization and promotes wound healing. LL37 is an endogenous human host defense peptide that modulates wound healing and angiogenesis and fights infection. Hence, we hypothesized that the administration of LL37 encapsulated in PLGA nanoparticles (PLGA-LL37 NP) promotes wound closure due to the sustained release of both LL37 and lactate. In full thickness excisional wounds, the treatment with PLGA-LL37 NP significantly accelerated wound healing compared to PLGA or LL37 administration alone. PLGA-LL37 NP-treated wounds displayed advanced granulation tissue formation by significant higher collagen deposition, re-epithelialized and neovascularized composition. PLGA-LL37 NP improved angiogenesis, significantly up-regulated IL-6 and VEGFa expression, and modulated the inflammatory wound response. In vitro, PLGA-LL37 NP induced enhanced cell migration but had no effect on the metabolism and proliferation of keratinocytes. It displayed antimicrobial activity on Escherichia coli. In conclusion, we developed a biodegradable drug delivery system that accelerated healing processes due to the combined effects of lactate and LL37 released from the nanoparticles.

  3. LL-37 complexation with glycosaminoglycans in cystic fibrosis lungs inhibits antimicrobial activity, which can be restored by hypertonic saline.

    LENUS (Irish Health Repository)

    Bergsson, Gudmundur

    2009-07-01

    There is an abundance of antimicrobial peptides in cystic fibrosis (CF) lungs. Despite this, individuals with CF are susceptible to microbial colonization and infection. In this study, we investigated the antimicrobial response within the CF lung, focusing on the human cathelicidin LL-37. We demonstrate the presence of the LL-37 precursor, human cathelicidin precursor protein designated 18-kDa cationic antimicrobial protein, in the CF lung along with evidence that it is processed to active LL-37 by proteinase-3. We demonstrate that despite supranormal levels of LL-37, the lung fluid from CF patients exhibits no demonstrable antimicrobial activity. Furthermore Pseudomonas killing by physiological concentrations of exogenous LL-37 is inhibited by CF bronchoalveolar lavage (BAL) fluid due to proteolytic degradation of LL-37 by neutrophil elastase and cathepsin D. The endogenous LL-37 in CF BAL fluid is protected from this proteolysis by interactions with glycosaminoglycans, but while this protects LL-37 from proteolysis it results in inactivation of LL-37 antimicrobial activity. By digesting glycosaminoglycans in CF BAL fluid, endogenous LL-37 is liberated and the antimicrobial properties of CF BAL fluid restored. High sodium concentrations also liberate LL-37 in CF BAL fluid in vitro. This is also seen in vivo in CF sputum where LL-37 is complexed to glycosaminoglycans but is liberated following nebulized hypertonic saline resulting in increased antimicrobial effect. These data suggest glycosaminoglycan-LL-37 complexes to be potential therapeutic targets. Factors that disrupt glycosaminoglycan-LL-37 aggregates promote the antimicrobial effects of LL-37 with the caveat that concomitant administration of antiproteases may be needed to protect the now liberated LL-37 from proteolytic cleavage.

  4. Expressions of Antimicrobial Peptides LL-37, Human Beta Defensin-2 and -3 in the Lesions of Cutaneous Tuberculosis and Tuberculids

    Directory of Open Access Journals (Sweden)

    Zheng Zhao

    2016-01-01

    Conclusions: Our study indicated that the expression of HBD-2 and HBD-3 mRNA and protein in lesions of cutaneous tuberculosis may be not consistent with that of tuberculids. However, an inherent limitation of the present study was that the sample size was small, and the roles and regulation mechanisms of LL-37, HBD-2, and HBD-3 in cutaneous tuberculosis and tuberculids need to be further investigated.

  5. Biological characteristics of a human specifically targeted antimicrobial peptide C16LL-37 againstStreptococcus mutans%针对变异链球菌的人源特异性靶向抗菌肽C16LL-37的生物学特性

    Institute of Scientific and Technical Information of China (English)

    车春晓; 姜科宇; 马媛媛; 曾飒; 周建业; 李志强; 何祥一

    2016-01-01

    Objective This study aimed to evaluate the biological characteristics of a human specifically targeted antimicrobial peptide C16LL-37 against Streptococcus mutans (S. mutans). Methods In this study, an antimicrobial peptide LL-37, a peptide derived from CSPC16 (S. mutans competence stimulating peptide), and recombinant peptide C16LL-37 were synthesized by Fmoc-chemistry-based strategy. The selectivity and antibacterial activity of C16LL-37 were identified by the colony counting method on microbial culture plates. After treatment of C16LL-37 at 32 μmol·L−1, the morphological changes in S. mutans were observed by using scanning electron microscopy (SEM). In addition, enzyme-linked immunosorbent assay was used to evaluate the hemolytic activity and antibacterial activity of C16LL-37 under different conditions. Results 1) The minimum inhibitory concentration of C16LL-37 was 16 μmol·L−1, and the minimum bactericidal concentration was 64 μmol·L−1. 2) The survival rate of S. mutans was 3.46% after C16LL-37 treatment at 64 μmol·L−1 for 30 min, whereas it was 0% at 64 μmol·L−1 for 60 min. The survival rates of four other kinds of bacteria were more than 60% at any time (P0.05). Conclusion C16LL-37 exhibited obvious specificity for S. mutans, strong antibacterial activity, low toxicity, and high stability. Thus, C16LL-37 has good potential in caries research and clinical application.%目的:研究针对变异链球菌(S. mutans)的人源特异性靶向抗菌肽C16LL-37的生物学特性。方法通过标准固相合成技术(Fmoc保护法)合成人源抗菌肽LL-37、S. mutans感受态刺激肽(CSP)C端16个氨基酸组成的多肽CSPC16及二者的重组多肽C16LL-37;以LL-37、CSPC16为对照组,采用平板菌落计数法检测C16LL-37对S. mutans、黏性放线菌、大肠埃希菌、嗜酸乳杆菌、金黄色葡萄球菌的抗菌活性及其对S. mutans的靶向性。通过扫描电子显微镜(SEM)观察,浓度为32

  6. Susceptibility of Pseudomonas aeruginosa biofilm to alpha-helical peptides: D-enantiomer of LL-37

    Directory of Open Access Journals (Sweden)

    Scott N. Dean

    2011-07-01

    Full Text Available Pseudomonas aeruginosa is a highly versatile opportunistic pathogen and its ability to produce biofilms is a direct impediment to the healing of wounds and recovery from infection. Interest in anti-microbial peptides has grown due to their potential therapeutic applications and their possible use against antibiotic resistant bacteria. LL-37 is the only cathelicidin expressed by humans. In this study, we tested LL-37 and the effect of a protease-resistant LL-37 peptide mimetic, the peptide enantiomer D-LL-37, for anti-microbial and anti-biofilm activity against P. aeruginosa. Both forms of the peptide were equally effective as anti-microbial peptides with similar killing kinetics. CD spectra were obtained to demonstrate the chirality of D- and L-LL-37, and the trypsin resistance of D-LL-37 was confirmed. The helical cathelicidin from the cobra Naja atra (NA-CATH, and synthetic peptide variations (ATRA-1, ATRA-2, NA-CATH:ATRA1-ATRA1 were also tested. Although the cobra cathelicidin and related peptides had strong anti-microbial activity, those tested did not inhibit Pseudomonas biofilm formation, neither did control peptides. Both D- and L-LL-37 inhibited the attachment of Pseudomonas to a 96-well plate and decreased the amount of pre-formed (established biofilm. D-LL-37 is able to promote Pseudomonas motility and decrease biofilm formation by altering the rate of twitching as well as by downregulating the expression of the biofilm-related genes, rhlA and rhlB, similar to L-LL-37. Both L- and D-LL-37 protected Galleria mellonella in vivo against Pseudomonas infection, while NA-CATH:ATRA1-ATRA1 peptide did not. This study demonstrates the ability and equivalence of D-LL-37 compared to L-LL-37 to promote bacterial twitching motility and inhibit biofilm formation, and protect against in vivo infection, and suggests that this peptide could be a critical advancement in the development of new treatments for P. aeruginosa infection.

  7. 抗菌肽LL-37的原核表达纯化及对假丝酵母菌的抑制作用%Prokaryotic expression and purification of antimicrobial peptide LL-37 and the inhibiting effect against Candida albicans

    Institute of Scientific and Technical Information of China (English)

    霍彦; 王芳; 孙蓓; 尹利荣; 张萍萍; 张钰娟; 张步美

    2016-01-01

    目的:研究抗菌肽LL-37通过促进阴道上皮细胞免疫因子的分泌抑制假丝酵母菌的作用。方法(1)构建LL-37原核表达载体pET-Duet/LL-37并在大肠埃希菌M15中诱导表达。对所表达的LL-37融合蛋白进行纯化及鉴定,并用K-B纸片法初步验证LL-37纯化蛋白的抗真菌活性。(2)纯化的LL-37蛋白加入到与假丝酵母菌共培养的人阴道上皮细胞[即外阴阴道假丝酵母菌病(VVC)阴道上皮细胞模型]中,并分为实验组与对照组(不加LL-37纯化蛋白),采用葡萄糖消耗法观察抑菌效果[以吸光度(A)值表示]。采用ELISA方法检测不同时间点干扰素γ(IFN-γ)、白细胞介素10(IL-10)水平及IFN-γ/IL-10比值的变化。结果(1)诱导表达的LL-37融合蛋白的浓度为433.92μg/ml,纯度达96%。K-B纸片法初步证实了LL-37纯化蛋白具有一定的抗真菌活性。(2)LL-37重组蛋白可明显抑制假丝酵母菌生长,实验组各时间点A值明显高于对照组(分别为:12 h:3.008±0.003、2.967±0.003;24 h:2.941±0.003、2.601±0.003;48 h:2.893±0.004、2.409±0.003),分别比较,差异均有统计学意义(P<0.01),并且随时间进展的下降趋势较对照组缓慢。两组IFN-γ、IL-10分泌水平均呈现先升后降的趋势,于24 h达高峰[实验组分别为:(104.00±1.07)、(108.4±0.7)pg/ml;对照组分别为:(85.17±0.28)、(151.6±0.6)pg/ml]。各时间点比较,实验组IFN-γ水平于24 h时明显高于对照组(P<0.01);各时间点的IL-10水平均低于对照组(P<0.01),且IFN-γ/IL-10比值均高于对照组(P<0.01)。结论(1)LL-37重组蛋白对假丝酵母菌具有明显的抑制作用。(2)LL-37重组蛋白通过影响IFN-γ、IL-10等免疫因子的分泌,调整阴道上皮细胞局部免疫,增强抵抗假丝酵母菌感染的能力。%Objective To study the inhibitory effect of antimicrobial

  8. Spotlight on Human LL-37, an Immunomodulatory Peptide with Promising Cell-Penetrating Properties

    Directory of Open Access Journals (Sweden)

    Marc Ferdinand Lensink

    2010-11-01

    Full Text Available Cationic antimicrobial peptides are major components of innate immunity and help control the initial steps of the infectious process. They are expressed not only by immunocytes, but also by epithelial cells. They share an amphipathic secondary structure with a polar cationic site, which explains their tropism for prokaryote membranes and their hydrophobic site contributing to the destructuration of these membranes. LL-37 is the only cationic antimicrobial peptide derived from human cathelicidin. LL-37 can also cross the plasma membrane of eukaryotic cells, probably through special domains of this membrane called lipid rafts. This transfer could be beneficial in the context of vaccination: the activation of intracellular toll-like receptors by a complex formed between CpG oligonucleotides and LL-37 could conceivably play a major role in the building of a cellular immunity involving NK cells.

  9. Synergistic anti-inflammatory activity of the antimicrobial peptides human beta-defensin-3 (hBD-3 and cathelicidin (LL-37 in a three-dimensional co-culture model of gingival epithelial cells and fibroblasts.

    Directory of Open Access Journals (Sweden)

    Telma Blanca Lombardo Bedran

    Full Text Available Given the spread of antibiotic resistance in bacterial pathogens, antimicrobial peptides that can also modulate the immune response may be a novel approach for effectively controlling periodontal infections. In the present study, we used a three-dimensional (3D co-culture model of gingival epithelial cells and fibroblasts stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide (LPS to investigate the anti-inflammatory properties of human beta-defensin-3 (hBD-3 and cathelicidin (LL-37 and to determine whether these antimicrobial peptides can act in synergy. The 3D co-culture model composed of gingival fibroblasts embedded in a collagen matrix overlaid with gingival epithelial cells had a synergistic effect with respect to the secretion of IL-6 and IL-8 in response to LPS stimulation compared to fibroblasts and epithelial cells alone. The 3D co-culture model was stimulated with non-cytotoxic concentrations of hBD-3 (10 and 20 µM and LL-37 (0.1 and 0.2 µM individually and in combination in the presence of A. actinomycetemcomitans LPS. A multiplex ELISA assay was used to quantify the secretion of 41 different cytokines. hBD-3 and LL-37 acted in synergy to reduce the secretion of GRO-alpha, G-CSF, IP-10, IL-6, and MCP-1, but only had an additive effect on reducing the secretion of IL-8 in response to A. actinomycetemcomitans LPS stimulation. The present study showed that hBD-3 acted in synergy with LL-37 to reduce the secretion of cytokines by an LPS-stimulated 3D model of gingival mucosa. This combination of antimicrobial peptides thus shows promising potential as an adjunctive therapy for treating inflammatory periodontitis.

  10. The pro-inflammatory peptide LL-37 promotes ovarian tumor progression through recruitment of multipotent mesenchymal stromal cells

    Science.gov (United States)

    Coffelt, Seth B.; Marini, Frank C.; Watson, Keri; Zwezdaryk, Kevin J.; Dembinski, Jennifer L.; LaMarca, Heather L.; Tomchuck, Suzanne L.; zu Bentrup, Kerstin Honer; Danka, Elizabeth S.; Henkle, Sarah L.; Scandurro, Aline B.

    2009-01-01

    Bone marrow-derived mesenchymal stem cells or multipotent mesenchymal stromal cells (MSCs) have been shown to engraft into the stroma of several tumor types, where they contribute to tumor progression and metastasis. However, the chemotactic signals mediating MSC migration to tumors remain poorly understood. Previous studies have shown that LL-37 (leucine, leucine-37), the C-terminal peptide of human cationic antimicrobial protein 18, stimulates the migration of various cell types and is overexpressed in ovarian, breast, and lung cancers. Although there is evidence to support a pro-tumorigenic role for LL-37, the function of the peptide in tumors remains unclear. Here, we demonstrate that neutralization of LL-37 in vivo significantly reduces the engraftment of MSCs into ovarian tumor xenografts, resulting in inhibition of tumor growth as well as disruption of the fibrovascular network. Migration and invasion experiments conducted in vitro indicated that the LL-37-mediated migration of MSCs to tumors likely occurs through formyl peptide receptor like-1. To assess the response of MSCs to the LL-37-rich tumor microenvironment, conditioned medium from LL-37-treated MSCs was assessed and found to contain increased levels of several cytokines and pro-angiogenic factors compared with controls, including IL-1 receptor antagonist, IL-6, IL-10, CCL5, VEGF, and matrix metalloproteinase-2. Similarly, Matrigel mixed with LL-37, MSCs, or the combination of the two resulted in a significant number of vascular channels in nude mice. These data indicate that LL-37 facilitates ovarian tumor progression through recruitment of progenitor cell populations to serve as pro-angiogenic factor-expressing tumor stromal cells. PMID:19234121

  11. Short KR-12 analogs designed from human cathelicidin LL-37 possessing both antimicrobial and antiendotoxic activities without mammalian cell toxicity.

    Science.gov (United States)

    Jacob, Binu; Park, Il-Seon; Bang, Jeong-Kyu; Shin, Song Yub

    2013-11-01

    KR-12 (residues 18-29 of LL-37) was known to be the smallest peptide of human cathelicidin LL-37 possessing antimicrobial activity. In order to optimize α-helical short antimicrobial peptides having both antimicrobial and antiendotoxic activities without mammalian cell toxicity, we designed and synthesized a series of KR-12 analogs. Highest hydrophobic analogs KR-12-a5 and KR-12-a6 displayed greater inhibition of lipopolysaccharide (LPS)-stimulated tumor necrosis factor-α production and higher LPS-binding activity. We have observed that antimicrobial activity is independent of charge, but LPS neutralization requires a balance of hydrophobicity and net positive charge. Among KR-12 analogs, KR-12-a2, KR-12-a3 and KR-12-a4 showed much higher cell specificity for bacteria over erythrocytes and retained antiendotoxic activity, relative to parental LL-37. KR-12-a5 displayed the strongest antiendotoxic activity but almost similar cell specificity as compared with LL-37. Also, these KR-12 analogs (KR-12-a2, KR-12-a3, KR-12-a4 and KR-12-a5) exhibited potent antimicrobial activity (minimal inhibitory concentration: 4 μM) against methicillin-resistant Staphylococcus aureus. Taken together, these KR-12 analogs have the potential for future development as a novel class of antimicrobial and anti-inflammatory therapeutic agents.

  12. Antimicrobial peptide LL-37 along with peptidoglycan drive monocyte polarization toward CD14(high)CD16(+) subset and may play a crucial role in the pathogenesis of psoriasis guttata.

    Science.gov (United States)

    Qian, Lei; Chen, Wei; Sun, Wen; Li, Ming; Zheng, Renshan; Qian, Qing; Lv, Lianzheng

    2015-01-01

    The human cathelicidin LL-37 peptide is overexpressed in psoriasis and has been demonstrated to be a multifunctional modulator of innate immune response elements, including monocytes. Monocytes, categorized into three populations based on the cell surface expression of CD14 and CD16, are activated in psoriasis guttate and are commonly triggered by streptococcal infections. Peptidoglycan (PGN) is a major cell-wall component of streptococcus, and an increasing number of PGN-containing cells have been detected in psoriasis. Since there are independent reports of both PGN and LL-37 influencing monocytes, we tried to evaluate the effect of human LL-37 on PGN-induced monocyte activity and differentiation and subsequently studied their correlation with the pathogenesis of psoriasis guttate. The results revealed that monocytes from the peripheral blood of healthy individuals resulted in their polarization toward the CD14(high)CD16(+) subset, when cultured with PGN in the presence of the LL-37 peptide. This peptide further induced PGN-driven differentiated monocytes into immature dendritic cells (iDC), as evident by the increased expression of CD1a, CD86, and HLA-DR markers, resulting in the induction of T cell proliferation and Th17 polarization. Furthermore, our data suggested that psoriasis guttata patients have significantly higher percentages of CD14(high)CD16(+) monocytes as well as circulating levels of LL-37, soluble form of triggering receptor expressed on myeloid cells (sTREM-1) levels, and anti-streptolysin O (ASO) levels, as compared to healthy controls. Psoriasis guttata patients also showed a positive correlation between the percentage of CD14(high)CD16(+) monocytes and the serum levels of sTREM-1 as well as the Psoriasis Area and Severity Index (PASI) scores. Therefore, we concluded that LL-37 in synergy with PGN directs monocyte polarization and differentiation into a proinflammatory phenotype, which might play a crucial role in the pathogenesis of psoriasis.

  13. The cationic peptide LL-37 binds Mac-1 (CD11b/CD18) with a low dissociation rate and promotes phagocytosis.

    Science.gov (United States)

    Zhang, Xianwei; Bajic, Goran; Andersen, Gregers R; Christiansen, Stig Hill; Vorup-Jensen, Thomas

    2016-05-01

    As a broad-spectrum anti-microbial peptide, LL-37 plays an important role in the innate immune system. A series of previous reports implicates LL-37 as an activator of various cell surface receptor-mediated functions, including chemotaxis in integrin CD11b/CD18 (Mac-1)-expressing cells. However, evidence is scarce concerning the direct binding of LL-37 to these receptors and investigations on the associated binding kinetics is lacking. Mac-1, a member of the β2 integrin family, is mainly expressed in myeloid leukocytes. Its critical functions include phagocytosis of complement-opsonized pathogens. Here, we report on interactions of LL-37 and its fragment FK-13 with the ligand-binding domain of Mac-1, the α-chain I domain. LL-37 bound the I-domain with an affinity comparable to the complement fragment C3d, one of the strongest known ligands for Mac-1. In cell adhesion assays both LL-37 and FK-13 supported binding by Mac-1 expressing cells, however, with LL-37-coupled surfaces supporting stronger cell adhesion than FK-13. Likewise, in phagocytosis assays with primary human monocytes both LL-37 and FK-13 enhanced uptake of particles coupled with these ligands but with a tendency towards a stronger uptake by LL-37.

  14. The human cathelicidin LL-37--A pore-forming antibacterial peptide and host-cell modulator.

    Science.gov (United States)

    Xhindoli, Daniela; Pacor, Sabrina; Benincasa, Monica; Scocchi, Marco; Gennaro, Renato; Tossi, Alessandro

    2016-03-01

    The human cathelicidin hCAP18/LL-37 has become a paradigm for the pleiotropic roles of peptides in host defence. It has a remarkably wide functional repertoire that includes direct antimicrobial activities against various types of microorganisms, the role of 'alarmin' that helps to orchestrate the immune response to infection, the capacity to locally modulate inflammation both enhancing it to aid in combating infection and limiting it to prevent damage to infected tissues, the promotion of angiogenesis and wound healing, and possibly also the elimination of abnormal cells. LL-37 manages to carry out all its reported activities with a small and simple, amphipathic, helical structure. In this review we consider how different aspects of its primary and secondary structures, as well as its marked tendency to form oligomers under physiological solution conditions and then bind to molecular surfaces as such, explain some of its cytotoxic and immunomodulatory effects. We consider its modes of interaction with bacterial membranes and capacity to act as a pore-forming toxin directed by our organism against bacterial cells, contrasting this with the mode of action of related peptides from other species. We also consider its different membrane-dependent effects on our own cells, which underlie many of its other activities in host defence. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.

  15. Dermcidin-derived peptides show a different mode of action than the cathelicidin LL-37 against Staphylococcus aureus.

    Science.gov (United States)

    Senyürek, Ilknur; Paulmann, Maren; Sinnberg, Tobias; Kalbacher, Hubert; Deeg, Martin; Gutsmann, Thomas; Hermes, Marina; Kohler, Thomas; Götz, Fritz; Wolz, Christiane; Peschel, Andreas; Schittek, Birgit

    2009-06-01

    Dermcidin (DCD) is an antimicrobial peptide which is constitutively expressed in eccrine sweat glands. By postsecretory proteolytic processing in sweat, the DCD protein gives rise to anionic and cationic DCD peptides with a broad spectrum of antimicrobial activity. Many antimicrobial peptides induce membrane permeabilization as part of their killing mechanism, which is accompanied by a loss of the bacterial membrane potential. In this study we show that there is a time-dependent bactericidal activity of anionic and cationic DCD-derived peptides which is followed by bacterial membrane depolarization. However, DCD-derived peptides do not induce pore formation in the membranes of gram-negative and gram-positive bacteria. This is in contrast to the mode of action of the cathelicidin LL-37. Interestingly, LL-37 as well as DCD-derived peptides inhibit bacterial macromolecular synthesis, especially RNA and protein synthesis, without binding to microbial DNA or RNA. Binding studies with components of the cell envelope of gram-positive and gram-negative bacteria and with model membranes indicated that DCD-derived peptides bind to the bacterial envelope but show only a weak binding to lipopolysaccharide (LPS) from gram-negative bacteria or to peptidoglycan, lipoteichoic acid, and wall teichoic acid, isolated from Staphylococcus aureus. In contrast, LL-37 binds strongly in a dose-dependent fashion to these components. Altogether, these data indicate that the mode of action of DCD-derived peptides is different from that of the cathelicidin LL-37 and that components of the bacterial cell envelope play a role in the antimicrobial activity of DCD.

  16. Topical Cathelicidin (LL-37) an Innate Immune Peptide Induces Acute Olfactory Epithelium Inflammation in a Mouse Model

    Science.gov (United States)

    Alt, Jeremiah A.; Qin, Xuan; Pulsipher, Abigail; Orb, Quinn; Orlandi, Richard R.; Zhang, Jianxing; Schults, Austin; Jia, Wanjian; Presson, Angela P.; Prestwich, Glenn; Oottamasathien, Siam

    2017-01-01

    Background Cathelicidin (LL-37) is an endogenous innate immune peptide that is elevated in patients with chronic rhinosinusitis (CRS). The role of LL-37 in olfactory epithelium (OE) inflammation remains unknown. We hypothesized that 1) LL-37 topically delivered would elicit profound OE inflammation, and 2) LL-37 induced inflammation is associated with increased infiltration of neutrophils and mast cells. Methods To test our hypothesis we challenged C57BL/6 mice intranasally with increasing concentrations of LL-37. At 24 hours tissues were examined histologically and scored for inflammatory cell infiltrate, edema, and secretory hyperplasia. In separate experiments, fluorescently conjugated LL-37 was instilled and tissues were examined at 0.5 and 24 hours. To test our last hypothesis, we performed tissue myeloperoxidase (MPO) assays for neutrophil activity and immunohistochemistry for tryptase to determine the mean number of mast cells per mm2. Results LL-37 caused increased inflammatory cell infiltrate, edema, and secretory cell hyperplasia of the sinonasal mucosa with higher LL-37 concentrations yielding significantly more inflammatory changes (p < 0.01). Fluorescent LL-37 demonstrated global sinonasal epithelial binding and tissue distribution. Further, higher concentrations of LL-37 led to significantly greater MPO levels with dose-dependent increases in mast cell infiltration (p < 0.01). Conclusions LL-37 has dramatic inflammatory effects in the OE mucosa that is dose-dependent. The observed inflammatory changes in the olfactory mucosa were associated with the infiltration of both neutrophils and mast cells. Our biologic model represents a new model to further investigate the role of LL-37 in OE inflammation. PMID:26346056

  17. Stability of the cathelicidin peptide LL-37 in a non-healing wound environment

    DEFF Research Database (Denmark)

    Grönberg, Alvar; Zettergren, Louise; Ågren, Sven Per Magnus

    2011-01-01

    aeruginosa that produce elastase, which degrades LL-37. This study investigated the stability of synthetic LL-37 against two types of proteinases in the presence or absence of wound fluid samples (diluted to 10-20%) from nine non-healing venous leg ulcers. Incubation of LL-37 (10 µg/ml) at 37°C for 6 h...

  18. Interaction between Antimicrobial Peptide LL -37 and Bacterial Membrane POPG by Molecular Dynamics Simulation%抗菌肽 LL -37与细菌膜 POPG相互作用的分子动力学模拟研究

    Institute of Scientific and Technical Information of China (English)

    毛文超; 赵立岭; 王吉华

    2016-01-01

    As a major component of the innate immune system ,human antimicrobial peptide LL -37 plays an important role in the protection of human resistance to disease .Residues 17-29 (FK -13) are consid‐ered as the core area of LL -37 antimicrobial activity .LL -37 can damage bacterial membrane with nega‐tive .LL -37 antimicrobial activity is closely related to secondary structure changes .In this work ,we studied the interaction between antimicrobial fragment FK -13 and of the bacterial membrane POPG by molecular dynamics simulation .The results show that the Coulomb interaction causes FK -13 close to the surface of the membrane rapidly and FK -13 can carpet the surface of the membrane .FK -13 has par‐tial helix structure when it interacts with membrane .In addition ,FK -13 can cause disturbance and de‐struction of the membrane and it is beneficial to exert antimicrobial activity .The residues 18 ~ 22 are key residues in the membrane function .So the work is useful for us not only understand the changes of FK -13 conformation and its damage to the membrane but also provide a theoretical basis for FK -13 as a ther‐apeutic application .%作为先天免疫系统的主要成分,人源抗菌肽L L -37在保护人类对抗疾病方面起了重要的角色。残基肽段17-29(FK -13)被认为是L L -37行使抗菌功能的核心区域,L L -37能对带负电的细菌膜产生破坏作用,其抗菌活性与二级结构的变化情况有关。用分子动力学模拟的方法研究了抗菌肽段 FK -13与带负电的细菌膜PO PG的相互作用。研究发现,库仑作用会使FK -13快速靠近膜的表面,然后像地毯一样覆盖在膜的表面;FK -13仍旧保持部分螺旋结构,并通过引起膜的扰动对膜产生破坏,以实现抗菌功能,而残基18~22是与膜作用的关键残基。研究FK -13与膜的相互作用,不仅可以从原子层面上了解L L -37对细菌膜作用的机理,也为基于L L -37

  19. Carbamylated LL-37 as a modulator of the immune response

    DEFF Research Database (Denmark)

    Koro, Catalin; Hellvard, Annelie; Delaleu, Nicolas;

    2016-01-01

    Carbamylation of lysine residues and protein N-termini is an ubiquitous, non-enzymatic post-translational modification. Carbamylation at sites of inflammation is due to cyanate formation during the neutrophil oxidative burst and may target lysine residues within the antimicrobial peptide LL-37...... to investigate how this modification affects the bactericidal, cytotoxic and immunomodulatory function of the peptide. The results indicated that LL-37 undergoes rapid modification in the presence of physiological concentrations of cyanate, yielding a spectrum of diverse carbamylated peptides. Mass spectrometry...... analyses revealed that the N-terminal amino group of Leu-1 was highly reactive and was modified almost instantly by cyanate to generate the predominant form of the modified peptide, named LL-37(C1). This was followed by the sequential carbamylation of Lys-8 and Lys-12 to yield LL-37(C8), and Lys-15...

  20. Phenylbutyrate induces LL-37-dependent autophagy and intracellular killing of Mycobacterium tuberculosis in human macrophages.

    Science.gov (United States)

    Rekha, Rokeya Sultana; Rao Muvva, S S V Jagadeeswara; Wan, Min; Raqib, Rubhana; Bergman, Peter; Brighenti, Susanna; Gudmundsson, Gudmundur H; Agerberth, Birgitta

    2015-01-01

    LL-37 is a human antimicrobial peptide (AMP) of the cathelicidin family with multiple activities including a mediator of vitamin D-induced autophagy in human macrophages, resulting in intracellular killing of Mycobacterium tuberculosis (Mtb). In a previous trial in healthy volunteers, we have shown that LL-37 expression and subsequent Mtb-killing can be further enhanced by 4-phenylbutyrate (PBA), also an inducer of LL-37 expression. Here, we explore a potential mechanism(s) behind PBA and LL-37-induced autophagy and intracellular killing of Mtb. Mtb infection of macrophages downregulated the expression of both the CAMP transcript and LL-37 peptide as well as certain autophagy-related genes (BECN1 and ATG5) at both the mRNA and protein levels. In addition, activation of LC3-II in primary macrophages and THP-1 cells was not detected. PBA and the active form of vitamin D3 (1,25[OH]2D3), separately or particularly in combination, were able to overcome Mtb-induced suppression of LL-37 expression. Notably, reactivation of autophagy occurred by stimulation of macrophages with PBA and promoted colocalization of LL-37 and LC3-II in autophagosomes. Importantly, PBA treatment failed to induce autophagy in Mtb-infected THP-1 cells, when the expression of LL-37 was silenced. However, PBA-induced autophagy was restored when the LL-37 knockdown cells were supplemented with synthetic LL-37. Interestingly, we have found that LL-37-induced autophagy was mediated via P2RX7 receptor followed by enhanced cytosolic free Ca(2+), and activation of AMPK and PtdIns3K pathways. Altogether, these results suggest a novel activity for PBA as an inducer of autophagy, which is LL-37-dependent and promotes intracellular killing of Mtb in human macrophages.

  1. Role of uropathogenic Escherichia coli OmpT in the resistance against human cathelicidin LL-37.

    Science.gov (United States)

    Brannon, John R; Thomassin, Jenny-Lee; Desloges, Isabelle; Gruenheid, Samantha; Le Moual, Hervé

    2013-08-01

    Uropathogenic Escherichia coli (UPEC) strains are among the most prevalent causative agents of urinary tract infections. To establish infection, UPEC must overcome the bactericidal action of host antimicrobial peptides. Previously, the enterohaemorrhagic E. coli outer membrane protease, OmpT, was shown to degrade and inactivate the human antimicrobial peptide LL-37. This study aims to investigate the involvement of UPEC OmpT in LL-37 degradation. An ompT deletion mutant was generated in the prototypical UPEC strain CFT073. Western blot analysis showed that the OmpT protein level is moderate in CFT073. In agreement, OmpT was shown to partially cleave LL-37. However, no difference in the minimum inhibitory concentration of LL-37 was observed between CFT073 and the ompT mutant. Plasmid complementation of ompT, which led to increased OmpT levels, resulted in complete cleavage of LL-37 and a fourfold increase in the minimum inhibitory concentration. The analysis of other UPEC isolates showed similar OmpT activity levels as CFT073. Although UPEC OmpT can cleave LL-37, we conclude that the low level of OmpT limits its contribution to LL-37 resistance. Collectively, these data suggest that UPEC OmpT is likely accompanied by other LL-37 resistance mechanisms.

  2. Generation of novel bone forming cells (monoosteophils from the cathelicidin-derived peptide LL-37 treated monocytes.

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    Zhifang Zhang

    Full Text Available BACKGROUND: Bone generation and maintenance involve osteoblasts, osteoclasts, and osteocytes which originate from unique precursors and rely on key growth factors for differentiation. However, an incomplete understanding of bone forming cells during wound healing has led to an unfilled clinical need such as nonunion of bone fractures. Since circulating monocytes are often recruited to sites of injury and may differentiate into various cell types including osteoclasts, we investigated the possibility that circulating monocytes in the context of tissue injury may also contribute to bone repair. In particular, we hypothesized that LL-37 (produced from hCAP-18, cathelicidin, which recruits circulating monocytes during injury, may play a role in bone repair. METHODS AND FINDINGS: Treatment of monocytes from blood with LL-37 for 6 days resulted in their differentiation to large adherent cells. Growth of LL-37-differentiated monocytes on osteologic discs reveals bone-like nodule formation by scanning electron microscopy (SEM. In vivo transplantation studies in NOD/SCID mice show that LL-37-differentiated monocytes form bone-like structures similar to endochondral bone formation. Importantly, LL-37-differentiated monocytes are distinct from conventional monocyte-derived osteoclasts, macrophages, and dendritic cells and do not express markers of the mesenchymal stem cells (MSC lineage, distinguishing them from the conventional precursors of osteoblasts. Furthermore, LL-37 differentiated monocytes express intracellular proteins of both the osteoblast and osteoclast lineage including osteocalcin (OC, osteonectin (ON, bone sialoprotein II (BSP II, osteopontin (OP, RANK, RANKL, MMP-9, tartrate resistant acid phosphatase (TRAP, and cathepsin K (CK. CONCLUSION: Blood derived monocytes treated with LL-37 can be differentiated into a novel bone forming cell that functions both in vitro and in vivo. We propose the name monoosteophil to indicate their monocyte

  3. Binding of LL-37 to model biomembranes: insight into target vs host cell recognition.

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    Sood, Rohit; Domanov, Yegor; Pietiäinen, Milla; Kontinen, Vesa P; Kinnunen, Paavo K J

    2008-04-01

    Pursuing the molecular mechanisms of the concentration dependent cytotoxic and hemolytic effects of the human antimicrobial peptide LL-37 on cells, we investigated the interactions of this peptide with lipids using different model membranes, together with fluorescence spectroscopy for the Trp-containing mutant LL-37(F27W). Minimum concentrations inhibiting bacterial growth and lipid interactions assessed by dynamic light scattering and monolayer penetration revealed the mutant to retain the characteristics of native LL-37. Although both LL-37 and the mutant intercalated effectively into zwitterionic phosphatidylcholine membranes the presence of acidic phospholipids caused augmented membrane binding. Interestingly, strongly attenuated intercalation of LL-37 into membranes containing both cholesterol and sphingomyelin (both at X=0.3) was observed. Accordingly, the distinction between target and host cells by LL-37 is likely to derive from i) acidic phospholipids causing enhanced association with the former cells as well as ii) from attenuated interactions with the outer surface of the plasma membrane of the peptide secreting host, imposed by its high content of cholesterol and sphingomyelin. Our results further suggest that LL-37 may exert its antimicrobial effects by compromising the membrane barrier properties of the target microbes by a mechanism involving cytotoxic oligomers, similarly to other peptides forming amyloid-like fibers in the presence of acidic phospholipids.

  4. Effects of the cathelicidin LL-37 on intestinal epithelial barrier integrity.

    Science.gov (United States)

    Otte, Jan-Michel; Zdebik, Anna-Elisabeth; Brand, Stephan; Chromik, Ansgar M; Strauss, Sarah; Schmitz, Frank; Steinstraesser, Lars; Schmidt, Wolfgang E

    2009-08-07

    The human cathelicidin LL-37 is involved in innate immune responses, angiogenesis and wound healing. Functions in maintenance and re-establishment of intestinal barrier integrity have not been characterized yet. Following direct and indirect stimulation of human colonic HT-29 and Caco-2 cells with LL-37 the cellular viability, rate of apoptosis, proliferation and wound healing were determined. Expression of mucins and growth factors was quantified by real-time PCR and Western blotting. Direct application of LL-37 stimulated migration in Caco-2 cells expressing the proposed LL-37 receptor P2X7. Intestinal epithelial cell (IEC) proliferation was not altered. Indirectly, LL-37 significantly enhanced IEC migration via release of growth factors from subepithelial fibroblasts and IEC. Furthermore, LL-37 induced the expression of protective mucins in IEC and abated tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induced apoptosis in IEC. LL-37 induced signaling is mediated in part by the P2X7 receptor, the epidermal growth factor receptor and the p38 mitogen-activated protein kinase (MAPK). LL-37 contributes to maintenance and re-establishment of the intestinal barrier integrity via direct and indirect pathways. These features, in addition to its known antimicrobial properties, suggest an important role for this peptide in intestinal homeostasis.

  5. Proteolytic inactivation of LL-37 by karilysin, a novel virulence mechanism of Tannerella forsythia.

    Science.gov (United States)

    Koziel, Joanna; Karim, Aabdulkarim Y; Przybyszewska, Kornelia; Ksiazek, Miroslaw; Rapala-Kozik, Maria; Nguyen, Ky-Anh; Potempa, Jan

    2010-01-01

    Tannerella forsythia is a gram-negative bacterium strongly associated with the development and/or progression of periodontal disease. Here, we have shown that a newly characterized matrix metalloprotease-like enzyme, referred to as karilysin, efficiently cleaved the antimicrobial peptide LL-37, significantly reducing its bactericidal activity. This may contribute to the resistance of T. forsythia to the antibacterial activity of LL-37, since their vitality was found not to be affected by LL-37 at concentrations up to 2.2 muM. Furthermore, proteolysis of LL-37 by karilysin not only abolished its ability to bind lipopolysaccharide (LPS) to quench endotoxin-induced proinflammatory activity, but LL-37 cleavage also caused the release of active endotoxin from the LPS/LL-37 complex. Proteolytic inactivation of LL-37 bactericidal activity by karilysin may protect LL-37-sensitive species in the subgingival plaque and maintain the local inflammatory reaction driven by LPS from gram-negative bacteria. Consequently, the karilysin protease may directly contribute to periodontal tissue damage and the development and/or progression of chronic periodontitis.

  6. 人cathelicidin抗菌肽LL-37在宿主防御系统中的作用%Function of LL-37 in the host defense system

    Institute of Scientific and Technical Information of China (English)

    李方舟; 胡海峰

    2011-01-01

    Cathelicidin is a family of antimicrobial peptides found in mammalian and produced by epithelial cells and LL-37 is the only cathelicidin discoverd in human. As a defensin, LL-37 plays an important role in the human innate immunity. Besides its broad spectrum antibacterial activity, LL-37 possesses additional biological functions including immunomodulatory functions, induction of angiogenesis, neutralination of the lipopolysaccharide, wound repair mechanisms and induction of cells apoptosis. This review describes the expression and distribution of LL-37 as well as its biological feature and mechanism.%存在于哺乳动物中的一类抗菌肽cathelicidin由上皮细胞产生,LL-37为目前在人体内仅发现的一种cathelicidin.同防御素一样,LL-37为人免疫防御系统的重要组成部分,除了具有广谱抗菌活性外,还有免疫调节、诱导血管生成、抗内毒素、促进损伤修复、诱导细胞凋亡等生物学功能.本文综述LL-37的表达分布、生物学活性及其作用机制.

  7. Activation of TRPV2 and BKCa channels by the LL-37 enantiomers stimulates calcium entry and migration of cancer cells

    Science.gov (United States)

    Guéguinou, Maxime; Chourpa, Igor; Fromont, Gaëlle; Bouchet, Ana Maria; Burlaud-Gaillard, Julien; Potier-Cartereau, Marie; Roger, Sébastien; Aucagne, Vincent; Chevalier, Stéphan; Vandier, Christophe

    2016-01-01

    Expression of the antimicrobial peptide hCAP18/LL-37 is associated to malignancy in various cancer forms, stimulating cell migration and metastasis. We report that LL-37 induces migration of three cancer cell lines by activating the TRPV2 calcium-permeable channel and recruiting it to pseudopodia through activation of the PI3K/AKT pathway. Ca2+ entry through TRPV2 cooperated with a K+ efflux through the BKCa channel. In a panel of human breast tumors, the expression of TRPV2 and LL-37 was found to be positively correlated. The D-enantiomer of LL-37 showed identical effects as the L-peptide, suggesting that no binding to a specific receptor was involved. LL-37 attached to caveolae and pseudopodia membranes and decreased membrane fluidity, suggesting that a modification of the physical properties of the lipid membrane bilayer was the underlying mechanism of its effects. PMID:26993604

  8. Antimicrobial Peptides in 2014

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    Guangshun Wang

    2015-03-01

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

  9. LL-37 via EGFR transactivation to promote high glucose-attenuated epithelial wound healing in organ-cultured corneas.

    Science.gov (United States)

    Yin, Jia; Yu, Fu-Shin X

    2010-04-01

    Purpose. Patients with diabetes are at higher risk for delayed corneal reepithelialization and infection. Previous studies indicated that high glucose (HG) impairs epidermal growth factor receptor (EGFR) signaling and attenuates ex vivo corneal epithelial wound healing. The authors investigated the effects of antimicrobial peptide LL-37 on HG-attenuated corneal epithelial EGFR signaling and wound closure. Methods. Human corneal epithelial cells (HCECs) were stimulated with LL-37. Heparin-binding EGF-like growth factor (HB-EGF) shedding was assessed by measuring the release of alkaline phosphatase (AP) in a stable HCEC line expressing HB-EGF-AP. Activation of EGFR, phosphoinositide 3-kinase (PI3K), and extracellular signal-regulated kinases 1/2 (ERK1/2) was determined by Western blot analysis. Corneal epithelial wound closure was assessed in cultured HCECs and porcine corneas. LL-37 expression was determined by immune dot blot. Results. LL-37 induced HB-EGF-AP release and EGFR activation in a dose-dependent manner. LL-37 prolonged EGFR signaling in response to wounding. LL-37 enhanced the closure of a scratch wound in cultured HCECs and partially rescued HG-attenuated wound healing in an EGFR- and a PI3K-dependent manner and restored HG-impaired EGFR signaling in cultured porcine corneas. HG attenuated wounding-induced LL-37 expression in cultured HCECs. Conclusions. LL-37 is a tonic factor promoting EGFR signaling and enhancing epithelial wound healing in normal and high glucose conditions. With both antimicrobial and regenerative capabilities, LL-37 may be a potential therapeutic for diabetic keratopathy.

  10. LL-37 induces polymerization and bundling of actin and affects actin structure.

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    Asaf Sol

    Full Text Available Actin exists as a monomer (G-actin which can be polymerized to filaments F-actin that under the influence of actin-binding proteins and polycations bundle and contribute to the formation of the cytoskeleton. Bundled actin from lysed cells increases the viscosity of sputum in lungs of cystic fibrosis patients. The human host defense peptide LL-37 was previously shown to induce actin bundling and was thus hypothesized to contribute to the pathogenicity of this disease. In this work, interactions between actin and the cationic LL-37 were studied by optical, proteolytic and surface plasmon resonance methods and compared to those obtained with scrambled LL-37 and with the cationic protein lysozyme. We show that LL-37 binds strongly to CaATP-G-actin while scrambled LL-37 does not. While LL-37, at superstoichiometric LL-37/actin concentrations polymerizes MgATP-G-actin, at lower non-polymerizing concentrations LL-37 inhibits actin polymerization by MgCl(2 or NaCl. LL-37 bundles Mg-F-actin filaments both at low and physiological ionic strength when in equimolar or higher concentrations than those of actin. The LL-37 induced bundles are significantly less sensitive to increase in ionic strength than those induced by scrambled LL-37 and lysozyme. LL-37 in concentrations lower than those needed for actin polymerization or bundling, accelerates cleavage of both monomer and polymer actin by subtilisin. Our results indicate that the LL-37-actin interaction is partially electrostatic and partially hydrophobic and that a specific actin binding sequence in the peptide is responsible for the hydrophobic interaction. LL-37-induced bundles, which may contribute to the accumulation of sputum in cystic fibrosis, are dissociated very efficiently by DNase-1 and also by cofilin.

  11. Mirolysin, a LysargiNase from Tannerella forsythia, proteolytically inactivates the human cathelicidin, LL-37.

    Science.gov (United States)

    Koneru, Lahari; Ksiazek, Miroslaw; Waligorska, Irena; Straczek, Anna; Lukasik, Magdalena; Madej, Mariusz; Thøgersen, Ida B; Enghild, Jan J; Potempa, Jan

    2016-12-20

    Tannerella forsythia is a periodontal pathogen expressing six secretory proteolytic enzymes with a unique multidomain structure referred to as KLIKK proteases. Two of these proteases, karilysin and mirolysin, were previously shown to protect the bacterium against complement-mediated bactericidal activity. The latter metalloprotease, however, was not characterized at the protein level. Therefore, we purified recombinant mirolysin and subjected it to detailed biochemical characterization. Mirolysin was obtained as a 66 kDa zymogen, which autoproteolytically processed itself into a 31 kDa active form via truncations at both the N- and C-termini. Further autodegradation was prevented by calcium. Substrate specificity was determined by the S1' subsite of the substrate-binding pocket, which shows strong preference for Arg and Lys at the carbonyl side of a scissile peptide bond (P1' residue). The protease cleaved an array of host proteins, including human fibronectin, fibrinogen, complement proteins C3, C4, and C5, and the antimicrobial peptide, LL-37. Degradation of LL-37 abolished not only the bactericidal activity of the peptide, but also its ability to bind lipopolysaccharide (LPS), thus quenching the endotoxin proinflammatory activity. Taken together, these results indicate that, through cleavage of LL-37 and complement proteins, mirolysin might be involved in evasion of the host immune response.

  12. Research status of defensins and cathelicidins/LL-37 in pulmonary anti-infection immune defense%防御素和cathelicidins/LL-37在肺部抗感染防御中的研究现状

    Institute of Scientific and Technical Information of China (English)

    郭书真; 李昌崇; 林立

    2014-01-01

    抗菌肽是宿主防御系统的重要组成部分.在人气道上皮中主要表达2种阳离子小分子抗菌肽,即防御素和cathelicidins/LL-37,它们通过直接杀菌、调节天然或适应性免疫、损伤修复等生物学活性对抗肺部常见病原体的侵袭.本文就防御素和cathelicidins/LL-37的来源及结构特征、表达调节、在肺部抗感染免疫防御中的作用进行综述.%Antimicrobial protein/peptides (AMPs) are an important part of the defense system.Defensins and cathelicidins/LL-37 are the two main small cationic AMPs which are present in airway epithelial cells.AMPs play a critical role in resisting pathongens of invading lung through direct antimicrobial activity,modulating innate or adaptive immunity,and wound repair.The orign and architectural feature,expression regulation and research progress in pulmonary anti-infection immune defense of defensins and cathelicidins/LL-37 are reviewed here.

  13. Cathelicidin LL-37 induces time-resolved release of LTB4 and TXA2 by human macrophages and triggers eicosanoid generation in vivo.

    Science.gov (United States)

    Wan, Min; Soehnlein, Oliver; Tang, Xiao; van der Does, Anne M; Smedler, Erik; Uhlén, Per; Lindbom, Lennart; Agerberth, Birgitta; Haeggström, Jesper Z

    2014-08-01

    In humans, LL-37 and eicosanoids are important mediators of inflammation and immune responses. Here we report that LL-37 promotes leukotriene B4 (LTB4) and thromboxane A2 (TXA2) generation by human monocyte-derived macrophages (HMDMs). LL-37 evokes calcium mobilization apparently via the P2X7 receptor (P2X7R), activation of ERK1/2 and p38 MAPKs, as well as cytosolic phospholipase A2 (cPLA2) and 5-lipoxygenase in HMDMs, leading to an early (1 h) release of LTB4. Similarly, TXA2 production at an early time involved the same signaling sequence along an LL-37-P2X7R-cPLA2-cyclooxygenase-1 (COX-1) axis. However, at later (6-8 h) time points, internalized LL-37 up-regulates COX-2 expression, promoting TXA2 production. Furthermore, intraperitoneal injection of mice with murine cathelicidin-related antimicrobial peptide (mCRAMP) induces significantly higher levels of LTB4 and TXA2 in mouse ascites rich in macrophages. Conversely, cathelicidin-deficient (Cnlp(-/-)) mice produce much less LTB4 and TXB2 in vivo in response to TNF-α compared with control mice. We conclude that LL-37 elicits a biphasic release of eicosanoids in macrophages with early, Ca(2+)-dependent formation of LTB4 and TXA2 followed by a late peak of TXA2, generated via induction of COX-2 by internalized LL-37, thus allowing eicosanoid production in a temporally controlled manner. Moreover, our findings provide evidence that LL-37 is an endogenous regulator of eicosanoid-dependent inflammatory responses in vivo.

  14. Vitamin D3 analog maxacalcitol (OCT) induces hCAP-18/LL-37 production in human oral epithelial cells.

    Science.gov (United States)

    Tada, Hiroyuki; Shimizu, Takamitsu; Nagaoka, Isao; Takada, Haruhiko

    2016-01-01

    Maxacalcitol (22-oxacalcitriol: OCT) is a synthetic vitamin D3 analog with a limited calcemic effect. In this study, we investigated whether OCT increases the production of LL-37/CAP-18, a human cathelicidin antimicrobial peptide, in human gingival/oral epithelial cells. A human gingival epithelial cell line (Ca9-22) and human oral epithelial cell lines (HSC-2, HSC-3, and HSC-4) exhibited the enhanced expression of LL-37 mRNA upon stimulation with OCT as well as active metabolites of vitamins D3 and D2. Among the human epithelial cell lines, Ca9-22 exhibited the strongest response to these vitamin D-related compounds. OCT induced the higher production of CAP-18 (ng/mL order) until 6 days time-dependently in Ca9-22 cells in culture. The periodontal pathogen Porphyromonas gingivalis was killed by treatment with the LL-37 peptide. These findings suggest that OCT induces the production of hCAP-18/LL-37 in a manner similar to that induced by the active metabolite of vitamin D3.

  15. 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.

  16. Antimicrobial Peptides

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    Ali Adem Bahar

    2013-11-01

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

  17. Modulation of neutrophil apoptosis by antimicrobial peptides.

    Science.gov (United States)

    Nagaoka, Isao; Suzuki, Kaori; Niyonsaba, François; Tamura, Hiroshi; Hirata, Michimasa

    2012-01-01

    Peptide antibiotics possess the potent antimicrobial activities against invading microorganisms and contribute to the innate host defense. Human antimicrobial peptides, α-defensins (human neutrophil peptides, HNPs), human β-defensins (hBDs), and cathelicidin (LL-37) not only exhibit potent bactericidal activities against Gram-negative and Gram-positive bacteria, but also function as immunomodulatory molecules by inducing cytokine and chemokine production, and inflammatory and immune cell activation. Neutrophil is a critical effector cell in host defense against microbial infection, and its lifespan is regulated by various pathogen- and host-derived substances. Here, we provided the evidence that HNP-1, hBD-3, and LL-37 cannot only destroy bacteria but also potently modulate (suppress) neutrophil apoptosis, accompanied with the phosphorylation of ERK-1/-2, the downregulation of tBid (an proapoptotic protein) and upregulation of Bcl-xL (an antiapoptotic protein), and the inhibition of mitochondrial membrane potential change and caspase 3 activity, possibly via the actions on the distinct receptors, the P2Y6 nucleotide receptor, the chemokine receptor CCR6, and the low-affinity formyl-peptide receptor FPRL1/the nucleotide receptor P2X7, respectively. Suppression of neutrophil apoptosis results in the prolongation of their lifespan and may be advantageous for the host defense against bacterial invasion.

  18. Deletion of mtrC in Haemophilus ducreyi increases sensitivity to human antimicrobial peptides and activates the CpxRA regulon.

    Science.gov (United States)

    Rinker, Sherri D; Trombley, Michael P; Gu, Xiaoping; Fortney, Kate R; Bauer, Margaret E

    2011-06-01

    Haemophilus ducreyi resists killing by antimicrobial peptides encountered during human infection, including cathelicidin LL-37, α-defensins, and β-defensins. In this study, we examined the role of the proton motive force-dependent multiple transferable resistance (MTR) transporter in antimicrobial peptide resistance in H. ducreyi. We found a proton motive force-dependent effect on H. ducreyi's resistance to LL-37 and β-defensin HBD-3, but not α-defensin HNP-2. Deletion of the membrane fusion protein MtrC rendered H. ducreyi more sensitive to LL-37 and human β-defensins but had relatively little effect on α-defensin resistance. The mtrC mutant 35000HPmtrC exhibited phenotypic changes in outer membrane protein profiles, colony morphology, and serum sensitivity, which were restored to wild type by trans-complementation with mtrC. Similar phenotypes were reported in a cpxA mutant; activation of the two-component CpxRA regulator was confirmed by showing transcriptional effects on CpxRA-regulated genes in 35000HPmtrC. A cpxR mutant had wild-type levels of antimicrobial peptide resistance; a cpxA mutation had little effect on defensin resistance but led to increased sensitivity to LL-37. 35000HPmtrC was more sensitive than the cpxA mutant to LL-37, indicating that MTR contributed to LL-37 resistance independent of the CpxRA regulon. The CpxRA regulon did not affect proton motive force-dependent antimicrobial peptide resistance; however, 35000HPmtrC had lost proton motive force-dependent peptide resistance, suggesting that the MTR transporter promotes proton motive force-dependent resistance to LL-37 and human β-defensins. This is the first report of a β-defensin resistance mechanism in H. ducreyi and shows that LL-37 resistance in H. ducreyi is multifactorial.

  19. Expression of the cathelicidin LL-37 is modulated by short chain fatty acids in colonocytes: relevance of signalling pathways

    OpenAIRE

    Schauber, J; Svanholm, C; Termén, S; Iffland, K; Menzel, T.; Scheppach, W; Melcher, R.; Agerberth, B.; Lührs, H.; G. H. Gudmundsson

    2003-01-01

    Background and aims: Short chain fatty acids (SCFA) exert profound effects on the colonic mucosa. In particular, SCFA modulate mucosal immune functions. The antimicrobial cathelicidin LL-37 is expressed by colon epithelial cells. In the present study the effect of SCFA on LL-37 expression was investigated.

  20. The Effect of Calcipotriol on the Expression of Human β Defensin-2 and LL-37 in Cultured Human Keratinocytes

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    Beom Joon Kim

    2009-01-01

    Full Text Available Background. Vitamin D has been reported to regulate innate immunity by controlling the expression of antimicrobial peptides (AMPs. Objective. We investigated the effect of calcipotriol on the expression of AMPs in human cultured keratinocytes. Methods. Keratinocytes were treated with lipopolysaccharide (LPS, TNF-α, Calcipotriol and irradiated with UVB, cultured, and harvested. To assess the expression of human beta defensin-2 and LL-37 in the control group, not exposed to any stimulants, the experimental group was treated with LPS, TNF-α, or UVB, and another group was treated again with calcipotriol; reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemical staining were performed. Results. In the experimental group treated with LPS, UVB irradiation, and TNF-α, the expression of β-defensin and LL-37 was increased more than in the control group and then decreased in the experimental group treated with calcipotriol. Conclusions. Calcipotriol suppressed HBD-2 and LL-37, which were stimulated by UVB, LPS, and TNF-α.

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

    Science.gov (United States)

    Mariano, F S; Campanelli, A P; Nociti Jr, F H; Mattos-Graner, R O; Gonçalves, R B

    2012-11-01

    Neutrophils play an important role in periodontitis by producing nitric oxide (NO) and antimicrobial peptides, molecules with microbicidal activity via oxygen-dependent and -independent mechanisms, respectively. It is unknown whether variation in the production of antimicrobial peptides such as LL-37, human neutrophil peptides (HNP) 1-3, and NO by neutrophils influences the pathogenesis of periodontal diseases. We compared the production of these peptides and NO by lipopolysaccharide (LPS)-stimulated neutrophils isolated from healthy subjects and from patients with periodontitis. Peripheral blood neutrophils were cultured with or without Aggregatibacter actinomycetemcomitans-LPS (Aa-LPS), Porphyromonas gingivalis-LPS (Pg-LPS) and Escherichia coli-LPS (Ec-LPS). qRT-PCR was used to determine quantities of HNP 1-3 and LL-37 mRNA in neutrophils. Amounts of HNP 1-3 and LL-37 proteins in the cell culture supernatants were also determined by ELISA. In addition, NO levels in neutrophil culture supernatants were quantitated by the Griess reaction. Neutrophils from periodontitis patients cultured with Aa-LPS, Pg-LPS and Ec-LPS expressed higher HNP 1-3 mRNA than neutrophils from healthy subjects. LL-37 mRNA expression was higher in neutrophils from patients stimulated with Aa-LPS. Neutrophils from periodontitis patients produced significantly higher LL-37 protein levels than neutrophils from healthy subjects when stimulated with Pg-LPS and Ec-LPS, but no difference was observed in HNP 1-3 production. Neutrophils from periodontitis patients cultured or not with Pg-LPS and Ec-LPS produced significantly lower NO levels than neutrophils from healthy subjects. The significant differences in the production of LL-37 and NO between neutrophils from healthy and periodontitis subjects indicate that production of these molecules might influence individual susceptibility to important periodontal pathogens.

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

    Directory of Open Access Journals (Sweden)

    F.S. Mariano

    2012-11-01

    Full Text Available Neutrophils play an important role in periodontitis by producing nitric oxide (NO and antimicrobial peptides, molecules with microbicidal activity via oxygen-dependent and -independent mechanisms, respectively. It is unknown whether variation in the production of antimicrobial peptides such as LL-37, human neutrophil peptides (HNP 1-3, and NO by neutrophils influences the pathogenesis of periodontal diseases. We compared the production of these peptides and NO by lipopolysaccharide (LPS-stimulated neutrophils isolated from healthy subjects and from patients with periodontitis. Peripheral blood neutrophils were cultured with or without Aggregatibacter actinomycetemcomitans-LPS (Aa-LPS, Porphyromonas gingivalis-LPS (Pg-LPS and Escherichia coli-LPS (Ec-LPS. qRT-PCR was used to determine quantities of HNP 1-3 and LL-37 mRNA in neutrophils. Amounts of HNP 1-3 and LL-37 proteins in the cell culture supernatants were also determined by ELISA. In addition, NO levels in neutrophil culture supernatants were quantitated by the Griess reaction. Neutrophils from periodontitis patients cultured with Aa-LPS, Pg-LPS and Ec-LPS expressed higher HNP 1-3 mRNA than neutrophils from healthy subjects. LL-37 mRNA expression was higher in neutrophils from patients stimulated with Aa-LPS. Neutrophils from periodontitis patients produced significantly higher LL-37 protein levels than neutrophils from healthy subjects when stimulated with Pg-LPS and Ec-LPS, but no difference was observed in HNP 1-3 production. Neutrophils from periodontitis patients cultured or not with Pg-LPS and Ec-LPS produced significantly lower NO levels than neutrophils from healthy subjects. The significant differences in the production of LL-37 and NO between neutrophils from healthy and periodontitis subjects indicate that production of these molecules might influence individual susceptibility to important periodontal pathogens.

  3. Cationic antimicrobial peptides promote microbial mutagenesis and pathoadaptation in chronic infections.

    Directory of Open Access Journals (Sweden)

    Dominique H Limoli

    2014-04-01

    Full Text Available Acquisition of adaptive mutations is essential for microbial persistence during chronic infections. This is particularly evident during chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF patients. Thus far, mutagenesis has been attributed to the generation of reactive species by polymorphonucleocytes (PMN and antibiotic treatment. However, our current studies of mutagenesis leading to P. aeruginosa mucoid conversion have revealed a potential new mutagen. Our findings confirmed the current view that reactive oxygen species can promote mucoidy in vitro, but revealed PMNs are proficient at inducing mucoid conversion in the absence of an oxidative burst. This led to the discovery that cationic antimicrobial peptides can be mutagenic and promote mucoidy. Of specific interest was the human cathelicidin LL-37, canonically known to disrupt bacterial membranes leading to cell death. An alternative role was revealed at sub-inhibitory concentrations, where LL-37 was found to induce mutations within the mucA gene encoding a negative regulator of mucoidy and to promote rifampin resistance in both P. aeruginosa and Escherichia coli. The mechanism of mutagenesis was found to be dependent upon sub-inhibitory concentrations of LL-37 entering the bacterial cytosol and binding to DNA. LL-37/DNA interactions then promote translesion DNA synthesis by the polymerase DinB, whose error-prone replication potentiates the mutations. A model of LL-37 bound to DNA was generated, which reveals amino termini α-helices of dimerized LL-37 bind the major groove of DNA, with numerous DNA contacts made by LL-37 basic residues. This demonstrates a mutagenic role for antimicrobials previously thought to be insusceptible to resistance by mutation, highlighting a need to further investigate their role in evolution and pathoadaptation in chronic infections.

  4. Cathelicidins: peptides with antimicrobial, immunomodulatory, anti-inflammatory, angiogenic, anticancer and procancer activities.

    Science.gov (United States)

    Wong, Jack Ho; Ye, Xiu Juan; Ng, Tzi Bun

    2013-09-01

    The family of peptides designated as cathelicidins was identified over a decade ago. Cathelicidins have since gained increasing recognition, both as endogenous antibiotics and as effector molecules of the innate immune system. The human cathelicidin LL-37 is widely expressed in human tissues and plays diverse biological roles. It contributes substantially to host defense and impacts multiple aspects of immunity. In view of the escalating importance of cathelicidins, the activities of LL-37 with an emphasis on antimicrobial, immunomodulatory, anti-inflammatory, angiogenic, anticancer and procancer effects are discussed in this review article.

  5. Fungicidal mechanisms of cathelicidins LL-37 and CATH-2 revealed by live-cell imaging

    NARCIS (Netherlands)

    Ordonez Alvarez, Soledad; Amarullah, Ilham H; Wubbolts, Richard W; Veldhuizen, Edwin J A; Haagsman, Henk P

    2014-01-01

    Antifungal mechanisms of action of two cathelicidins, chicken CATH-2 and human LL-37, were studied and compared with the mode of action of the salivary peptide histatin 5 (Hst5). Candida albicans was used as a model organism for fungal pathogens. Analysis by live-cell imaging showed that the peptide

  6. 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

  7. Enhanced antitumor effects by docetaxel/LL37-loaded thermosensitive hydrogel nanoparticles in peritoneal carcinomatosis of colorectal cancer.

    Science.gov (United States)

    Fan, Rangrang; Tong, Aiping; Li, Xiaoling; Gao, Xiang; Mei, Lan; Zhou, Liangxue; Zhang, Xiaoning; You, Chao; Guo, Gang

    2015-01-01

    Intraperitoneal chemotherapy was explored in clinical trials as a promising strategy to improve the therapeutic effects of chemotherapy. In this work, we developed a biodegradable and injectable drug-delivery system by coencapsulation of docetaxel (Doc) and LL37 peptide polymeric nanoparticles (Doc+LL37 NPs) in a thermosensitive hydrogel system for colorectal peritoneal carcinoma therapy. Firstly, polylactic acid (PLA)-Pluronic L35-PLA (PLA-L35-PLA) was explored to prepare the biodegradable Doc+LL37 NPs using a water-in-oil-in-water double-emulsion solvent-evaporation method. Then, biodegradable and injectable thermosensitive PLA-L64-PLA hydrogel with lower sol-gel transition temperature at around body temperature was also prepared. Transmission electron microscopy revealed that the Doc+LL37 NPs formed with the PLA-L35-PLA copolymer were spherical. Fourier-transform infrared spectra certified that Doc and LL37 were encapsulated successfully. X-ray diffraction diagrams indicated that Doc was encapsulated amorphously. Intraperitoneal administration of Doc+LL37 NPs-hydrogel significantly suppressed the growth of HCT116 peritoneal carcinomatosis in vivo and prolonged the survival of tumor-bearing mice. Our results suggested that Doc+LL37 NPs-hydrogel may have potential clinical applications.

  8. Anti-antimicrobial Peptides

    Science.gov (United States)

    Ryan, Lloyd; Lamarre, Baptiste; Diu, Ting; Ravi, Jascindra; Judge, Peter J.; Temple, Adam; Carr, Matthew; Cerasoli, Eleonora; Su, Bo; Jenkinson, Howard F.; Martyna, Glenn; Crain, Jason; Watts, Anthony; Ryadnov, Maxim G.

    2013-01-01

    Antimicrobial or host defense peptides are innate immune regulators found in all multicellular organisms. Many of them fold into membrane-bound α-helices and function by causing cell wall disruption in microorganisms. Herein we probe the possibility and functional implications of antimicrobial antagonism mediated by complementary coiled-coil interactions between antimicrobial peptides and de novo designed antagonists: anti-antimicrobial peptides. Using sequences from native helical families such as cathelicidins, cecropins, and magainins we demonstrate that designed antagonists can co-fold with antimicrobial peptides into functionally inert helical oligomers. The properties and function of the resulting assemblies were studied in solution, membrane environments, and in bacterial culture by a combination of chiroptical and solid-state NMR spectroscopies, microscopy, bioassays, and molecular dynamics simulations. The findings offer a molecular rationale for anti-antimicrobial responses with potential implications for antimicrobial resistance. PMID:23737519

  9. 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.

  10. Regulation of the human cathelicidin antimicrobial peptide gene by 1α,25-dihydroxyvitamin D3 in primary immune cells

    DEFF Research Database (Denmark)

    Lowry, Malcolm B; Guo, Chunxiao; Borregaard, Niels;

    2014-01-01

    Production of the human cathelicidin antimicrobial peptide gene (hCAP18/LL-37), is regulated by 1α,25-dihydroxyvitamin D3 (1,25D3) and is critical in the killing of pathogens by innate immune cells. In addition, secreted LL-37 binds extracellular receptors and modulates the recruitment and activity...... of both innate and adaptive immune cells. Evidence suggests that during infections activated immune cells locally produce increased levels of 1,25D3 thus increasing production of hCAP18/LL-37. The relative expression levels of hCAP18/LL-37 among different immune cell types are not well characterized....... The aim of this study was to determine the relative levels of hCAP18/LL-37 in human peripheral blood immune cells and determine to what extent 1,25D3 increased its expression in peripheral blood-derived cells. We show for the first time, a hierarchy of expression of hCAP18 in freshly isolated cells...

  11. The relationship of serum vitamins A, D, E and LL-37 levels with allergic status, tonsillar virus detection and immune response

    Science.gov (United States)

    Elenius, Varpu; Palomares, Oscar; Waris, Matti; Turunen, Riitta; Puhakka, Tuomo; Rückert, Beate; Vuorinen, Tytti; Allander, Tobias; Vahlberg, Tero; Akdis, Mübeccel; Camargo, Carlos A.; Akdis, Cezmi A.; Jartti, Tuomas

    2017-01-01

    Background Tonsils have an active role in immune defence and inducing and maintaining tolerance to allergens. Vitamins A, D, and E, and antimicrobial peptide LL-37 may have immunomodulatory effects. We studied how their serum levels were associated with allergy status, intratonsillar/nasopharyngeal virus detection and intratonsillar expression of T cell- and innate immune response-specific cytokines, transcription factors and type I/II/III interferons in patients undergoing tonsillectomy. Methods 110 elective tonsillectomy patients participated. Serum levels of vitamins A, 25(OH)D, and E, LL-37 and allergen-specific IgE as well as nasopharyngeal/intratonsillar respiratory viruses were analyzed. The mRNA expression of IFN-α, IFN-β, IFN-γ, IL-10, IL-13, IL-17, IL-28, IL-29, IL-37, TGF-β, FOXP3, GATA3, RORC2 and Tbet in tonsils were analyzed by quantitative RT-PCR. Results The median age of the patients was 16 years (range 3–60), 28% of subjects had atopy, and 57% carried ≥1 respiratory virus in nasopharynx. Detection of viruses decreased by age. Higher vitamin A levels showed borderline significance with less viral detection (P = 0.056). Higher 25(OH)D was associated with less allergic rhinitis and atopy (P < 0.05) and higher vitamin E with less self-reported allergy (P < 0.05). In gene expression analyses, 25(OH)D was associated with higher IL-37, vitamin A with higher IFN-γ and vitamin E with less IL-28 (P < 0.05). LL-37 was associated with less FOXP3, RORC2 and IL-17 in tonsils (P < 0.05). Conclusions Vitamin D and E levels were associated with less allergic disorders. Vitamin A was linked to antiviral and vitamin D with anti-inflammatory activity. LL-37 and was linked to T regulatory cell effects. PMID:28235040

  12. Human cathelicidin LL-37 enhance the antibiofilm effect of EGCG on Streptococcus mutans

    OpenAIRE

    Guo, Yi-jie; Zhang, Bo; Feng, Xue-song; Ren, Hui-xun; Xu, Ji-ru

    2016-01-01

    Background Streptococcus mutans forms biofilms as a resistance mechanism against antimicrobial agents in the human oral cavity. We recently showed that human cathelicidin LL-37 exhibits inhibitory effects on biofilm formation of S. mutans through interaction with lipoteichoic acid (LTA), but without antibacterial or biofilm dispersal abilities. (−)-Epigallocatechin gallate (EGCG) is the most abundant constituent of tea catechins that has the greatest anti-infective potential to inhibit the gr...

  13. Expression of LL-37, Human beta Defensin-2, and CCR6 mRNA in Patients with Psoriasis Vulgaris

    Institute of Scientific and Technical Information of China (English)

    李东升; 李家文; 段逸群; 周小勇

    2004-01-01

    To investigate whether LL-37 and human beta defensin-2 (hBD-2) is related to the patients with psoriasis seldom having skin infections and explore the role of the two peptides and CCR6 (the receptor of hBD-2) in the pathogenesis of psoriasis, the expression levels of mRNA of LL-37, hBD-2, and CCR6 in skin lesions of patients with psoriasis vulgaris were detected by using RT-PCR. The results showed that the mRNA expression levels of the two peptides and CCR6 in psoriatic lesions all increased compared with the normal skin (P<0. 001). It was suggested that upregulated expression of LL-37 and hBD-2 might be the main reason that result in the the skin of patients with psoriasis being seldom infected, and the two peptides and CCR6 might play crucial roles in the pathogenesis of psoriasis.

  14. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    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...

  15. Bordetella pertussis lipid A glucosamine modification confers resistance to cationic antimicrobial peptides and increases resistance to outer membrane perturbation.

    Science.gov (United States)

    Shah, Nita R; Hancock, Robert E W; Fernandez, Rachel C

    2014-08-01

    Bordetella pertussis, the causative agent of whooping cough, has many strategies for evading the human immune system. Lipopolysaccharide (LPS) is an important Gram-negative bacterial surface structure that activates the immune system via Toll-like receptor 4 and enables susceptibility to cationic antimicrobial peptides (CAMPs). We show modification of the lipid A region of LPS with glucosamine increased resistance to numerous CAMPs, including LL-37. Furthermore, we demonstrate that this glucosamine modification increased resistance to outer membrane perturbation.

  16. Enhanced antitumor effects by docetaxel/LL37-loaded thermosensitive hydrogel nanoparticles in peritoneal carcinomatosis of colorectal cancer

    Directory of Open Access Journals (Sweden)

    Fan R

    2015-12-01

    Full Text Available Rangrang Fan,1,* Aiping Tong,1,* Xiaoling Li,1 Xiang Gao,1 Lan Mei,1 Liangxue Zhou,1 Xiaoning Zhang,2 Chao You,1 Gang Guo1 1State Key Laboratory of Biotherapy and Cancer Center, Department of Neurosurgery, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, People’s Republic of China; 2Department of Pharmacology and Pharmaceutical Sciences, School of Medicine, Tsinghua University, and Collaborative Innovation Center for Biotherapy, Beijing, People’s Republic of China *These authors contributed equally to this work Abstract: Intraperitoneal chemotherapy was explored in clinical trials as a promising strategy to improve the therapeutic effects of chemotherapy. In this work, we developed a biodegradable and injectable drug-delivery system by coencapsulation of docetaxel (Doc and LL37 peptide polymeric nanoparticles (Doc+LL37 NPs in a thermosensitive hydrogel system for colorectal peritoneal carcinoma therapy. Firstly, polylactic acid (PLA-Pluronic L35-PLA (PLA-L35-PLA was explored to prepare the biodegradable Doc+LL37 NPs using a water-in-oil-in-water double-emulsion solvent-evaporation method. Then, biodegradable and injectable thermosensitive PLA-L64-PLA hydrogel with lower sol–gel transition temperature at around body temperature was also prepared. Transmission electron microscopy revealed that the Doc+LL37 NPs formed with the PLA-L35-PLA copolymer were spherical. Fourier-transform infrared spectra certified that Doc and LL37 were encapsulated successfully. X-ray diffraction diagrams indicated that Doc was encapsulated amorphously. Intraperitoneal administration of Doc+LL37 NPs–hydrogel significantly suppressed the growth of HCT116 peritoneal carcinomatosis in vivo and prolonged the survival of tumor-bearing mice. Our results suggested that Doc+LL37 NPs–hydrogel may have potential clinical applications. Keywords: intraperitoneal chemotherapy, injectable, nanoparticles, hydrogel

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

    Science.gov (United States)

    Kooi, Cora; Sokol, Pamela A

    2009-09-01

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

  18. Modulation of toll-like receptor 7 and LL-37 expression in colon and breast epithelial cells by human beta-defensin-2.

    Science.gov (United States)

    Stroinigg, Nora; Srivastava, Maya D

    2005-01-01

    Breast-feeding decreases maternal breast cancer risk. Breast-fed infants have fewer infections and inflammatory-allergic diseases. We recently found inducible antimicrobial and immunomodulatory protein human beta3-defensin 2 (HBD-2) in significant amounts in human milk. We investigated if HBD-2 could contribute to benefits of breast-feeding for the mother and the child by immunomodulating effects on breast and gut epithelial cells. Human CaCo-2 colon and MCF-7 breast cell lines were cultured for 16-48 hours in RPMI 1640 5% fetal calf serum with and without HBD-2 at 0.1, 0.5, and 1.0 microg/mL. RNA was extracted and reverse-transcription polymerase chain reaction (RT-PCR) and gel electrophoresis for toll-like receptor pathway members, antimicrobial peptides, and cytokines/receptors was performed. Primers were designed with www.ncbi.nlm.nih.gov and www.broad. mit.edu/cgibin/primer/primer3 www.cgi. Based on RT-PCR results, cells were stained by immunohistochemistry using anti-toll-like receptor (TLR)-7 and anti-LL37 antibodies and DAKO EnVision Plus kits. Supernatants were analyzed for interleukin (IL)-8 and liver and activation-regulated chemokine (LARC) using enzyme-linked immunosorbent assay. In CaCo-2, messenger RNA (mRNA) for TLR-7, IL-1R-associated kinase, alpha-defensins (human neutrophil peptides 1-3), and IL-8 were down-regulated; cathelicidin/LL37 and NFkappaBp65 were up-regulated. LARC mRNA and protein were detected after 48 hours. TLR-7 protein, LARC, and IL-8 decreased with HBD-2; LL-37 protein greatly increased. In MCF-7, mRNA for LL37, inhibitor of kappaBalpha, NFkappaBp65, Tollip, MyD88, IL-1R-associated kinase, and TLR-7 were up-regulated. LARC mRNA was turned off. TLR-7 protein was induced. LARC was not detected. IL-8 was barely detectable with or without HBD-2. beta-Defensins 1 and 2; alpha-defensins 5 and 6; TLRs 1, 2, 3, 4, 5, 6, 8, 9, and 10; nucleotide binding oligomerization domain protein-2, and CCR6 mRNA were unaffected. HBD-2 profoundly

  19. High Specific Selectivity and Membrane-Active Mechanism of Synthetic Cationic Hybrid Antimicrobial Peptides Based on the Peptide FV7

    Science.gov (United States)

    Tan, Tingting; Wu, Di; Li, Weizhong; Zheng, Xin; Li, Weifen; Shan, Anshan

    2017-01-01

    Hybrid peptides integrating different functional domains of peptides have many advantages, such as remarkable antimicrobial activity, lower hemolysis and ideal cell selectivity, compared with natural antimicrobial peptides. FV7 (FRIRVRV-NH2), a consensus amphiphilic sequence was identified as being analogous to host defense peptides. In this study, we designed a series of hybrid peptides FV7-LL-37 (17–29) (FV-LL), FV7-magainin 2 (9–21) (FV-MA) and FV7-cecropin A (1–8) (FV-CE) by combining the FV7 sequence with the small functional sequences LL-37 (17–29) (LL), magainin 2 (9–21) (MA) and cecropin A (1–8) (CE) which all come from well-described natural peptides. The results demonstrated that the synthetic hybrid peptides, in particular FV-LL, had potent antibacterial activities over a wide range of Gram-negative and Gram-positive bacteria with lower hemolytic activity than other peptides. Furthermore, fluorescent spectroscopy indicated that the hybrid peptide FV-LL exhibited marked membrane destruction by inducing outer and inner bacterial membrane permeabilization, while scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that FV-LL damaged membrane integrity by disrupting the bacterial membrane. Inhibiting biofilm formation assays also showed that FV-LL had similar anti-biofilm activity compared with the functional peptide sequence FV7. Synthetic cationic hybrid peptides based on FV7 could provide new models for combining different functional domains and demonstrate effective avenues to screen for novel antimicrobial agents. PMID:28178190

  20. High Specific Selectivity and Membrane-Active Mechanism of Synthetic Cationic Hybrid Antimicrobial Peptides Based on the Peptide FV7.

    Science.gov (United States)

    Tan, Tingting; Wu, Di; Li, Weizhong; Zheng, Xin; Li, Weifen; Shan, Anshan

    2017-02-06

    Hybrid peptides integrating different functional domains of peptides have many advantages, such as remarkable antimicrobial activity, lower hemolysis and ideal cell selectivity, compared with natural antimicrobial peptides. FV7 (FRIRVRV-NH₂), a consensus amphiphilic sequence was identified as being analogous to host defense peptides. In this study, we designed a series of hybrid peptides FV7-LL-37 (17-29) (FV-LL), FV7-magainin 2 (9-21) (FV-MA) and FV7-cecropin A (1-8) (FV-CE) by combining the FV7 sequence with the small functional sequences LL-37 (17-29) (LL), magainin 2 (9-21) (MA) and cecropin A (1-8) (CE) which all come from well-described natural peptides. The results demonstrated that the synthetic hybrid peptides, in particular FV-LL, had potent antibacterial activities over a wide range of Gram-negative and Gram-positive bacteria with lower hemolytic activity than other peptides. Furthermore, fluorescent spectroscopy indicated that the hybrid peptide FV-LL exhibited marked membrane destruction by inducing outer and inner bacterial membrane permeabilization, while scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that FV-LL damaged membrane integrity by disrupting the bacterial membrane. Inhibiting biofilm formation assays also showed that FV-LL had similar anti-biofilm activity compared with the functional peptide sequence FV7. Synthetic cationic hybrid peptides based on FV7 could provide new models for combining different functional domains and demonstrate effective avenues to screen for novel antimicrobial agents.

  1. APD2: the updated antimicrobial peptide database and its application in peptide design.

    Science.gov (United States)

    Wang, Guangshun; Li, Xia; Wang, Zhe

    2009-01-01

    The antimicrobial peptide database (APD, http://aps.unmc.edu/AP/main.php) has been updated and expanded. It now hosts 1228 entries with 65 anticancer, 76 antiviral (53 anti-HIV), 327 antifungal and 944 antibacterial peptides. The second version of our database (APD2) allows users to search peptide families (e.g. bacteriocins, cyclotides, or defensins), peptide sources (e.g. fish, frogs or chicken), post-translationally modified peptides (e.g. amidation, oxidation, lipidation, glycosylation or d-amino acids), and peptide binding targets (e.g. membranes, proteins, DNA/RNA, LPS or sugars). Statistical analyses reveal that the frequently used amino acid residues (>10%) are Ala and Gly in bacterial peptides, Cys and Gly in plant peptides, Ala, Gly and Lys in insect peptides, and Leu, Ala, Gly and Lys in amphibian peptides. Using frequently occurring residues, we demonstrate database-aided peptide design in different ways. Among the three peptides designed, GLK-19 showed a higher activity against Escherichia coli than human LL-37.

  2. Antimicrobial Peptides in Echinoderms

    OpenAIRE

    Li, C; Haug, T; K Stensvåg

    2010-01-01

    Antimicrobial peptides (AMPs) are important immune effector molecules for invertebrates, including echinoderms, which lack a vertebrate-type adaptive immune system. Here we summarize the knowledge of such peptides in echinoderms. Strongylocins are a novel family of cysteine-rich AMPs, recently identified in the sea urchins, Strongylocentrotus droebachiensis and S. purpuratus. Although these molecules present diverse amino acid sequences, they share an identical cysteine arrangement pattern, d...

  3. Role of urinary cathelicidin LL-37 and human β-defensin 1 in uncomplicated Escherichia coli urinary tract infections

    DEFF Research Database (Denmark)

    Nielsen, Karen L; Dynesen, Pia; Larsen, Preben

    2014-01-01

    Cathelicidin (LL-37) and human β-defensin 1 (hBD-1) are important components of the innate defense in the urinary tract. The aim of this study was to characterize whether these peptides are important for developing uncomplicated Escherichia coli urinary tract infections (UTIs...

  4. 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.

  5. Leukotriene B4-mediated release of antimicrobial peptides against cytomegalovirus is BLT1 dependent.

    Science.gov (United States)

    Gaudreault, Eric; Gosselin, Jean

    2007-09-01

    Leukotriene B4 (LTB(4)) is a potent lipid mediator of inflammation that possesses antiviral activities. Here we provide evidence that LTB(4)-mediated defense against in vitro cytomegalovirus (CMV) infection of human leukocytes involves activation of the high-affinity LTB(4) receptor (BLT1) and neutrophil degranulation. Treatment of CMV-infected peripheral blood leukocytes with LTB(4) (10 nM) leads to a significant reduction in viral titers. This activity involves neutrophil activation through the BLT1 receptor, because no reduction in viral titers was observed after neutrophil depletion from cellular preparation or when leukocytes were pretreated with the BLT1 antagonist U75,302. Direct stimulation of neutrophils with LTB(4) (in the presence or absence of CMV) leads to the release of myeloperoxidase, alpha-defensins, eosinophil-derived neurotoxin, and the human cathelicidin LL-37 in a BLT1-dependent manner. LTB(4) does not act exclusively on the secretion of preformed antimicrobial peptides, but also acts on the synthesis of selected peptides as reflected by the increase in transcriptional levels of eosinophil-derived neurotoxin (EDN) and LL-37 in LTB(4)-treated neutrophils. Treatment of cell cultures with neutralizing antibodies directed against alpha-defensins, EDN, and LL-37 significantly reduces the antiviral effect of LTB(4), suggesting that LTB(4) may act through the release of antimicrobial peptides. Ex vivo experiments using LTB(4)-treated neutrophils from peritoneal washing of wild-type and BLT1 knockout mice further supported the role played by antimicrobial peptides in LTB(4)-mediated antiviral activity toward CMV. These results provide evidence of a mechanism by which LTB(4) induces host defense against viral infection.

  6. 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.

  7. Antimicrobial peptides in Echinoderms

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    C Li

    2010-05-01

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

  8. The Alzheimer's disease-associated amyloid beta-protein is an antimicrobial peptide.

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    Stephanie J Soscia

    Full Text Available BACKGROUND: The amyloid beta-protein (Abeta is believed to be the key mediator of Alzheimer's disease (AD pathology. Abeta is most often characterized as an incidental catabolic byproduct that lacks a normal physiological role. However, Abeta has been shown to be a specific ligand for a number of different receptors and other molecules, transported by complex trafficking pathways, modulated in response to a variety of environmental stressors, and able to induce pro-inflammatory activities. METHODOLOGY/PRINCIPAL FINDINGS: Here, we provide data supporting an in vivo function for Abeta as an antimicrobial peptide (AMP. Experiments used established in vitro assays to compare antimicrobial activities of Abeta and LL-37, an archetypical human AMP. Findings reveal that Abeta exerts antimicrobial activity against eight common and clinically relevant microorganisms with a potency equivalent to, and in some cases greater than, LL-37. Furthermore, we show that AD whole brain homogenates have significantly higher antimicrobial activity than aged matched non-AD samples and that AMP action correlates with tissue Abeta levels. Consistent with Abeta-mediated activity, the increased antimicrobial action was ablated by immunodepletion of AD brain homogenates with anti-Abeta antibodies. CONCLUSIONS/SIGNIFICANCE: Our findings suggest Abeta is a hitherto unrecognized AMP that may normally function in the innate immune system. This finding stands in stark contrast to current models of Abeta-mediated pathology and has important implications for ongoing and future AD treatment strategies.

  9. Regulation of the human cathelicidin antimicrobial peptide gene by 1α,25-dihydroxyvitamin D3 in primary immune cells.

    Science.gov (United States)

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

    2014-09-01

    Production of the human cathelicidin antimicrobial peptide gene (hCAP18/LL-37), is regulated by 1α,25-dihydroxyvitamin D3 (1,25D3) and is critical in the killing of pathogens by innate immune cells. In addition, secreted LL-37 binds extracellular receptors and modulates the recruitment and activity of both innate and adaptive immune cells. Evidence suggests that during infections activated immune cells locally produce increased levels of 1,25D3 thus increasing production of hCAP18/LL-37. The relative expression levels of hCAP18/LL-37 among different immune cell types are not well characterized. The aim of this study was to determine the relative levels of hCAP18/LL-37 in human peripheral blood immune cells and determine to what extent 1,25D3 increased its expression in peripheral blood-derived cells. We show for the first time, a hierarchy of expression of hCAP18 in freshly isolated cells with low levels in lymphocytes, intermediate levels in monocytes and the highest levels found in neutrophils. In peripheral blood-derived cells, the highest levels of hCAP18 following treatment with 1,25D3 were in macrophages, while comparatively lower levels were found in GM-CSF-derived dendritic cells and osteoclasts. We also tested whether treatment with parathyroid hormone in combination with 1,25D3 would enhance hCAP18 induction as has been reported in skin cells, but we did not find enhancement in any immune cells tested. Our results indicate that hCAP18 is expressed at different levels according to cell type and lineage. Furthermore, potent induction of hCAP18 by 1,25D3 in macrophages and dendritic cells may modulate functions of both innate and adaptive immune cells at sites of infection.

  10. Nasal Levels of Antimicrobial Peptides in Allergic Asthma Patients and Healthy Controls: Differences and Effect of a Short 1,25(OH2 Vitamin D3 Treatment.

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    Willemien Thijs

    Full Text Available Allergy is often accompanied by infections and lower levels of antimicrobial peptides (AMPs. Vitamin D has been shown to increase expression of selected AMPs. In this study we investigated whether antimicrobial peptide levels in nasal secretions of allergic asthma patients are lower than in healthy controls, and whether administration of the active form of vitamin D (1,25(OH2D3 affects these antimicrobial peptide levels.The levels of antimicrobial peptides in nasal secretions were compared between 19 allergic asthma patients and 23 healthy controls. The effect of seven days daily oral treatment with 2 μg 1,25(OH2D3 on antimicrobial peptides in nasal secretions was assessed in a placebo-controlled cross-over clinical study.Levels of neutrophil α-defensins (human neutrophil peptides 1-3; HNP1-3 and lipocalin 2 (LCN2; also known as NGAL were significantly lower in asthmatics, but no differences in LL-37 and SLPI were detected. Treatment with a short-term 1,25(OH2D3 caused a small increase in HNP1-3, but not when the asthma and control groups were analyzed separately. LL-37, LCN2 and SLPI did not change after treatment with 1,25(OH2D3.Levels of the antimicrobial peptides HNP1-3 and LCN2 are lower in nasal secretions in asthmatics and are not substantially affected by a short-term treatment with active vitamin D.

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

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    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.

  12. APD: the Antimicrobial Peptide Database

    OpenAIRE

    Wang, Zhe; Wang, Guangshun

    2004-01-01

    An antimicrobial peptide database (APD) has been established based on an extensive literature search. It contains detailed information for 525 peptides (498 antibacterial, 155 antifungal, 28 antiviral and 18 antitumor). APD provides interactive interfaces for peptide query, prediction and design. It also provides statistical data for a select group of or all the peptides in the database. Peptide information can be searched using keywords such as peptide name, ID, length, net charge, hydrophob...

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

    Science.gov (United States)

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

    2011-05-01

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

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

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    Sophie eCotton

    2012-08-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    to their therapeutic application. High manufacturing costs associated with amino acid precursors have limited the delivery of inexpensive therapeutics through industrial-scale chemical synthesis. Conversely, the production of peptides in bacteria by recombinant DNA technology has been impeded by the antimicrobial...... activity of these peptides and their susceptibility to proteolytic degradation, while subsequent purification of recombinant peptides often requires multiple steps and has not been cost-effective. Here we have developed methodologies appropriate for large-scale industrial production of HDPs; in particular......, we describe (i) a method, using fusions to SUMO, for producing high yields of intact recombinant HDPs in bacteria without significant toxicity and (ii) a simplified 2-step purification method appropriate for industrial use. We have used this method to produce seven HDPs to date (IDR1, MX226, LL37...

  17. APD: the Antimicrobial Peptide Database.

    Science.gov (United States)

    Wang, Zhe; Wang, Guangshun

    2004-01-01

    An antimicrobial peptide database (APD) has been established based on an extensive literature search. It contains detailed information for 525 peptides (498 antibacterial, 155 antifungal, 28 antiviral and 18 antitumor). APD provides interactive interfaces for peptide query, prediction and design. It also provides statistical data for a select group of or all the peptides in the database. Peptide information can be searched using keywords such as peptide name, ID, length, net charge, hydrophobic percentage, key residue, unique sequence motif, structure and activity. APD is a useful tool for studying the structure-function relationship of antimicrobial peptides. The database can be accessed via a web-based browser at the URL: http://aps.unmc.edu/AP/main.html.

  18. Antimicrobial peptides in crustaceans

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    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.

  19. 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.

  20. 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.

  1. Tuberculin skin test and interferon-gamma release assay values are associated with antimicrobial peptides expression in  polymorphonuclear cells during latent tuberculous infection

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    Julio E Castañeda-Delgado

    2014-06-01

    Full Text Available It has been reported that patients with progressive tuberculosis (TB express abundant amounts of the antimicrobial peptides (AMPs cathelicidin (LL-37 and human neutrophil peptide-1 (HNP-1 in circulating cells, whereas latent TB infected donors showed no differences when compared with purified protein derivative (PPD and QuantiFERON®-TB Gold (QFT-healthy individuals. The aim of this study was to determine whether LL-37 and HNP-1 production correlates with higher tuberculin skin test (TST and QFT values in TB household contacts. Twenty-six TB household contact individuals between 26-58 years old TST and QFT positive with at last two years of latent TB infection were recruited. AMPs production by polymorphonuclear cells was determined by flow cytometry and correlation between TST and QFT values was analysed. Our results showed that there is a positive correlation between levels of HNP-1 and LL-37 production with reactivity to TST and/or QFT levels. This preliminary study suggests the potential use of the expression levels of these peptides as biomarkers for progression in latent infected individuals.

  2. Ciprofloxacin Affects Host Cells by Suppressing Expression of the Endogenous Antimicrobial Peptides Cathelicidins and Beta-Defensin-3 in Colon Epithelia

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    Protim Sarker

    2014-07-01

    Full Text Available Antibiotics exert several effects on host cells including regulation of immune components. Antimicrobial peptides (AMPs, e.g., cathelicidins and defensins display multiple functions in innate immunity. In colonic mucosa, cathelicidins are induced by butyrate, a bacterial fermentation product. Here, we investigated the effect of antibiotics on butyrate-induced expression of cathelicidins and beta-defensins in colon epithelial cells. Real-time PCR analysis revealed that ciprofloxacin and clindamycin reduce butyrate-induced transcription of the human cathelicidin LL-37 in the colonic epithelial cell line HT-29. Suppression of LL-37 peptide/protein by ciprofloxacin was confirmed by Western blot analysis. Immunohistochemical analysis demonstrated that ciprofloxacin suppresses the rabbit cathelicidin CAP-18 in rectal epithelia of healthy and butyrate-treated Shigella-infected rabbits. Ciprofloxacin also down-regulated butyrate-induced transcription of the human beta-defensin-3 in HT-29 cells. Microarray analysis of HT-29 cells revealed upregulation by butyrate with subsequent down-regulation by ciprofloxacin of additional genes encoding immune factors. Dephosphorylation of histone H3, an epigenetic event provided a possible mechanism of the suppressive effect of ciprofloxacin. Furthermore, LL-37 peptide inhibited Clostridium difficile growth in vitro. In conclusion, ciprofloxacin and clindamycin exert immunomodulatory function by down-regulating AMPs and other immune components in colonic epithelial cells. Suppression of AMPs may contribute to the overgrowth of C. difficile, causing antibiotic-associated diarrhea.

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

    Science.gov (United States)

    Kubicek-Sutherland, Jessica Z.; Lofton, Hava; Vestergaard, Martin; Hjort, Karin; Ingmer, Hanne; Andersson, Dan I.

    2017-01-01

    Background The clinical development of antimicrobial peptides (AMPs) is currently under evaluation to combat the rapid increase in MDR bacterial pathogens. However, many AMPs closely resemble components of the human innate immune system and the ramifications of prolonged bacterial exposure to AMPs are not fully understood. Objectives We show that in vitro serial passage of a clinical USA300 MRSA strain in a host-mimicking environment containing host-derived AMPs results in the selection of stable AMP resistance. Methods Serial passage experiments were conducted using steadily increasing concentrations of LL-37, PR-39 or wheat germ histones. WGS and proteomic analysis by MS were used to identify the molecular mechanism associated with increased tolerance of AMPs. AMP-resistant mutants were characterized by measuring in vitro fitness, AMP and antibiotic susceptibility, and virulence in a mouse model of sepsis. Results AMP-resistant Staphylococcus aureus mutants often displayed little to no fitness cost and caused invasive disease in mice. Further, this phenotype coincided with diminished susceptibility to both clinically prescribed antibiotics and human defence peptides. Conclusions These findings suggest that therapeutic use of AMPs could select for virulent mutants with cross-resistance to human innate immunity as well as antibiotic therapy. Thus, therapeutic use of AMPs and the implications of cross-resistance need to be carefully monitored and evaluated. PMID:27650186

  4. Staphylococcus epidermidis Antimicrobial δ-Toxin (Phenol-Soluble Modulin-γ) Cooperates with Host Antimicrobial Peptides to Kill Group A Streptococcus

    Science.gov (United States)

    Cogen, Anna L.; Yamasaki, Kenshi; Muto, Jun; Sanchez, Katheryn M.; Crotty Alexander, Laura; Tanios, Jackelyn; Lai, Yuping; Kim, Judy E.; Nizet, Victor; Gallo, Richard L.

    2010-01-01

    Antimicrobial peptides play an important role in host defense against pathogens. Recently, phenol-soluble modulins (PSMs) from Staphylococcus epidermidis (S. epidermidis) were shown to interact with lipid membranes, form complexes, and exert antimicrobial activity. Based on the abundance and innocuity of the cutaneous resident S. epidermidis, we hypothesized that their PSMs contribute to host defense. Here we show that S. epidermidis δ-toxin (PSMγ) is normally present in the epidermis and sparsely in the dermis of human skin using immunohistochemistry. Synthetic δ-toxin interacted with neutrophil extracellular traps (NETs) and colocalized with cathelicidin while also inducing NET formation in human neutrophils. In antimicrobial assays against Group A Streptococcus (GAS), δ-toxin cooperated with CRAMP, hBD2, and hBD3. In whole blood, addition of δ-toxin exerted a bacteriostatic effect on GAS, and in NETs, δ-toxin increased their killing capacity against this pathogen. Coimmunoprecipitation and tryptophan spectroscopy demonstrated direct binding of δ-toxin to host antimicrobial peptides LL-37, CRAMP, hBD2, and hBD3. Finally, in a mouse wound model, GAS survival was reduced (along with Mip-2 cytokine levels) when the wounds were pretreated with δ-toxin. Thus, these data suggest that S. epidermidis–derived δ-toxin cooperates with the host-derived antimicrobial peptides in the innate immune system to reduce survival of an important human bacterial pathogen. PMID:20052280

  5. Staphylococcus epidermidis antimicrobial delta-toxin (phenol-soluble modulin-gamma cooperates with host antimicrobial peptides to kill group A Streptococcus.

    Directory of Open Access Journals (Sweden)

    Anna L Cogen

    Full Text Available Antimicrobial peptides play an important role in host defense against pathogens. Recently, phenol-soluble modulins (PSMs from Staphylococcus epidermidis (S. epidermidis were shown to interact with lipid membranes, form complexes, and exert antimicrobial activity. Based on the abundance and innocuity of the cutaneous resident S. epidermidis, we hypothesized that their PSMs contribute to host defense. Here we show that S. epidermidis delta-toxin (PSMgamma is normally present in the epidermis and sparsely in the dermis of human skin using immunohistochemistry. Synthetic delta-toxin interacted with neutrophil extracellular traps (NETs and colocalized with cathelicidin while also inducing NET formation in human neutrophils. In antimicrobial assays against Group A Streptococcus (GAS, delta-toxin cooperated with CRAMP, hBD2, and hBD3. In whole blood, addition of delta-toxin exerted a bacteriostatic effect on GAS, and in NETs, delta-toxin increased their killing capacity against this pathogen. Coimmunoprecipitation and tryptophan spectroscopy demonstrated direct binding of delta-toxin to host antimicrobial peptides LL-37, CRAMP, hBD2, and hBD3. Finally, in a mouse wound model, GAS survival was reduced (along with Mip-2 cytokine levels when the wounds were pretreated with delta-toxin. Thus, these data suggest that S. epidermidis-derived delta-toxin cooperates with the host-derived antimicrobial peptides in the innate immune system to reduce survival of an important human bacterial pathogen.

  6. 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.

  7. Leukotriene B4 induces release of antimicrobial peptides in lungs of virally infected mice.

    Science.gov (United States)

    Gaudreault, Eric; Gosselin, Jean

    2008-05-01

    Leukotriene B(4) (LTB(4)) is a lipid mediator of inflammation that was recently shown to exert antiviral activities. In this study, we demonstrate that the release of antimicrobial proteins by neutrophils contribute to an early host defense against influenza virus infection in vitro as well as in vivo. Daily i.v. treatments with LTB(4) lead to a significant decrease in lung viral loads at day 5 postinfection in mice infected with influenza A virus compared with the placebo-treated group. This reduction in viral load was not present in mice deficient in the high-affinity LTB(4) receptor. Viral clearance in lungs was associated with up-regulated presence of antimicrobial peptides such as beta-defensin-3, members of the mouse eosinophil-related RNase family, and the mouse cathelicidin-related antimicrobial peptide. Our results also indicate that neutrophils are important in the antiviral effect of LTB(4). Viral loads in neutrophil-depleted mice were not diminished by LTB(4) administration, and a substantial reduction in the presence of murine cathelicidin-related antimicrobial peptide and the murine eosinophil-related RNase family in lung tissue was observed. Moreover, in vitro treatment of human neutrophil cultures with LTB(4) led rapidly to the secretion of the human cathelicidin LL-37 and eosinophil-derived neurotoxin, known as antiviral peptides. Pretreatment of cell cultures with specific LTB(4) receptor antagonists clearly demonstrate the implication of the high-affinity LTB(4) receptor in the LTB(4)-mediated activity. Together, these results demonstrate the importance of neutrophils and the secretion of antimicrobial peptides during the early immune response mediated by LTB(4) against a viral pathogen.

  8. Insect inducible antimicrobial peptides and their applications.

    Science.gov (United States)

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

    2013-12-01

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

  9. Membrane selectivity and disordering mechanism of antimicrobial peptide protegrin-1

    Science.gov (United States)

    Ishitsuka, Yuji

    Protegrin-1 (PG-1) is a beta-sheet antimicrobial peptide (AMP), a class of peptides innate to various organisms and functions as a defense agent against harmful microorganisms by means of membrane disordering. Characteristic chemical and structural properties of AMPs allow selective interaction against invaders' cell membranes. Despite their enormous biomedical potential, progress towards developing them into therapeutic agents has been hampered by a lack of insight into their mechanism of action. AMP insertion assays using Langmuir monolayers reveal that both electrostatic properties of the lipid head group as well as the packing density of the lipid tail group play important roles in determining the membrane selectivity of AMPs. These results help elucidate how the AMP selectively targets the cell membrane of microorganisms over the cell membrane of the host. In addition, these results also explain the higher hemolytic ability of PG-1 against human red blood cells (RBCs) compared to the hemolytic ability of PG-1 against sheep and pig RBCs. Synchrotron X-ray reflectivity shows that PG-1 penetrates into the lipid layer. Grazing incidence X-ray diffraction and fluorescence microscopy indicate that the insertion of PG-1 disorders tail group packing. Membrane selectivity and insertion location information of AMPs with different primary sequence and secondary structure have been obtained by using a truncated version of PG-1: PC-17, and an alpha-helical AMP, LL-37, respectively. The similarity of the membrane disordering process across these various peptides motivated us to test the membrane disordering effect of molecules designed to mimic these peptides. Peptide-mimics based on meta-phenylene ethynylenes demonstrate similar membrane disordering effects, showing that the potency of AMPs is derived from their overall chemical and structural properties, rather than exact peptide sequence. Atomic force microscopy (AFM) was used to directly image first, the PG-1

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

    Directory of Open Access Journals (Sweden)

    Louise Bjerkan

    2016-07-01

    Full Text Available Thymic stromal lymphopoietin (TSLP is a pleiotropic cytokine, hitherto mostly known to be involved in inflammatory responses and immunoregulation. The human tslp gene gives rise to two transcription and translation variants: a long form (lfTSLP that is induced by inflammation, and a short, constitutively-expressed form (sfTSLP, that appears to be downregulated by inflammation. The TSLP forms can be produced by a number of cell types, including epithelial and dendritic cells (DCs. lfTSLP can activate mast cells, DCs, and T cells through binding to the lfTSLP receptor (TSLPR and has a pro-inflammatory function. In contrast, sfTSLP inhibits cytokine secretion of DCs, but the receptor mediating this effect is unknown. Our recent studies have demonstrated that both forms of TSLP display potent antimicrobial activity, exceeding that of many other known antimicrobial peptides (AMPs, with sfTSLP having the strongest effect. The AMP activity is primarily mediated by the C-terminal region of the protein and is localized within a 34-mer peptide (MKK34 that spans the C-terminal α-helical region in TSLP. Fluorescent studies of peptide-treated bacteria, electron microscopy, and liposome leakage models showed that MKK34 exerted membrane-disrupting effects comparable to those of LL-37. Expression of TSLP in skin, oral mucosa, salivary glands, and intestine is part of the defense barrier that aids in the control of both commensal and pathogenic microbes.

  11. Antimicrobial peptides in the brain.

    Science.gov (United States)

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

    2010-10-01

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

  12. [Heterogenous expression of antimicrobial peptides].

    Science.gov (United States)

    Song, Shanshan; Hu, Guobin; Dong, Xianzhi

    2009-12-01

    Antimicrobial peptides (AMPs), a class of short proteins with a broad spectrum of antibacterial activities, are isolated from a wide variety of animals, both vertebrates and invertebrates, and plants as well as from bacteria and fungi. They are a key component of the innate immune response in most multicellular organisms. Owing to their potent, broad-spectrum antibacterial activities and uneasy developing of drug resistance, these peptides are of great clinical significance. However, preparation of AMPs at a large scale is a severe challenge to the development of the commercial products. Undoubtedly, construction of high-level biological expression systems for the production of AMPs is the key in its clinical application process. Herein, we summarize the progress in researches on heterogenous expression of AMPs in prokaryotic expression systems and eukaryotic expression systems.

  13. The first salamander defensin antimicrobial peptide.

    Directory of Open Access Journals (Sweden)

    Ping Meng

    Full Text Available Antimicrobial peptides have been widely identified from amphibian skins except salamanders. A novel antimicrobial peptide (CFBD was isolated and characterized from skin secretions of the salamander, Cynops fudingensis. The cDNA encoding CFBD precursor was cloned from the skin cDNA library of C. fudingensis. The precursor was composed of three domains: signal peptide of 17 residues, mature peptide of 41 residues and intervening propeptide of 3 residues. There are six cysteines in the sequence of mature CFBD peptide, which possibly form three disulfide-bridges. CFBD showed antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Candida albicans and Escherichia coli. This peptide could be classified into family of β-defensin based on its sequence similarity with β-defensins from other vertebrates. Evolution analysis indicated that CFBD was close to fish β-defensin. As far as we know, CFBD is the first β-defensin antimicrobial peptide from salamanders.

  14. Antimicrobial peptides in human sepsis

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    Lukas eMartin

    2015-08-01

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

  15. Antimicrobial peptides in innate immune responses

    DEFF Research Database (Denmark)

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

    2008-01-01

    Antimicrobial peptides (AMPs) are ancient effector molecules in the innate immune response of eukaryotes. These peptides are important for the antimicrobial efficacy of phagocytes and for the innate immune response mounted by epithelia of humans and other mammals. AMPs are generated either by de ...

  16. Antimicrobial peptides in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    A Bogaerts

    2010-01-01

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

  17. Antimicrobial peptides important in innate immunity.

    Science.gov (United States)

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

    2011-10-01

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

  18. Serum Levels of LL-37 and Inflammatory Cytokines in Plaque and Guttate Psoriasis

    Directory of Open Access Journals (Sweden)

    Young Ji Hwang

    2014-01-01

    Full Text Available Psoriasis is a chronic inflammatory skin disease. It is assumed that the plaque phenotype of psoriasis is associated with T helper (Th 1 immune response activation, while the guttate phenotype is associated with the Th17 immune response. Previous investigations of differences in the serum levels of cytokines relative to the clinical psoriatic phenotype have yielded conflicting results. This study compared the levels of circulating inflammatory cytokines and LL-37 relative to the morphological phenotype in patients with psoriasis. Seventy-four age-matched patients with psoriasis (32 with guttate psoriasis and 42 with plaque psoriasis and 12 healthy controls were included. A multiplex cytokine assay and enzyme-linked immunosorbent assay were used to measure levels of Th1- and Th17-derived cytokines and LL-37, respectively. Circulating levels of interferon- (IFN-γ, interleukin- (IL-1RA, IL-2, and IL-23, and LL-37 were significantly higher in patients with psoriasis than in healthy controls. However, the serum levels of inflammatory cytokines (IL-7, IL-22, and IL-23 and LL-37 did not differ significantly between the guttate and plaque phenotypes of psoriasis. There was a positive correlation between serum inflammatory cytokine levels and the Psoriasis Area and Severity Index score. The findings of this study suggest that the serum levels of inflammatory cytokines reflect the disease activity rather than determine the morphological phenotype.

  19. Antimicrobial peptides of multicellular organisms

    Science.gov (United States)

    Zasloff, Michael

    2002-01-01

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

  20. Antimicrobial peptide action on parasites.

    Science.gov (United States)

    Torrent, Marc; Pulido, David; Rivas, Luis; Andreu, David

    2012-08-01

    Diseases caused by protozoan parasites can pose a severe thread to human health and are behind some serious neglected tropical diseases like malaria and leishmaniasis. Though several different drugs have been developed in order to eradicate these diseases, a successful candidate has not yet been discovered. Among the most active compounds tested, antimicrobial peptides (AMPs) are particularly appealing because of their wide spectrum of action. AMPs have been described to perturb protozoan homeostasis by disrupting the cellular membranes but also by interfering with key processes in the parasite metabolism. In this review we describe the diverse mechanisms of action of AMPs on protozoan targets and how they can be exploited to treat diseases. Moreover, we describe with detail the antimicrobial action of AMPs on two major parasitical infections: leishmaniasis and malaria. All the features reviewed here show that AMPs are promising drugs to target protozoan parasites and that further understanding of the mechanism of action of these compounds will lead to improved drugs that could be worth to test in a clinical phase.

  1. Antimicrobial Peptides: Multifunctional Drugs for Different Applications

    Directory of Open Access Journals (Sweden)

    Lea-Jessica Albrecht

    2012-02-01

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

  2. Novel histone-derived antimicrobial peptides use different antimicrobial mechanisms.

    Science.gov (United States)

    Pavia, Kathryn E; Spinella, Sara A; Elmore, Donald E

    2012-03-01

    The increase in multidrug resistant bacteria has sparked an interest in the development of novel antibiotics. Antimicrobial peptides that operate by crossing the cell membrane may also have the potential to deliver drugs to intracellular targets. Buforin 2 (BF2) is an antimicrobial peptide that shares sequence identity with a fragment of histone subunit H2A and whose bactericidal mechanism depends on membrane translocation and DNA binding. Previously, novel histone-derived antimicrobial peptides (HDAPs) were designed based on properties of BF2, and DesHDAP1 and DesHDAP3 showed significant antibacterial activity. In this study, their DNA binding, permeabilization, and translocation abilities were assessed independently and compared to antibacterial activity to determine whether they share a mechanism with BF2. To investigate the importance of proline in determining the peptides' mechanisms of action, proline to alanine mutants of the novel peptides were generated. DesHDAP1, which shows significant similarities to BF2 in terms of secondary structure, translocates effectively across lipid vesicle and bacterial membranes, while the DesHDAP1 proline mutant shows reduced translocation abilities and antimicrobial potency. In contrast, both DesHDAP3 and its proline mutant translocate poorly, though the DesHDAP3 proline mutant is more potent. Our findings suggest that a proline hinge can promote membrane translocation in some peptides, but that the extent of its effect on permeabilization depends on the peptide's amphipathic properties. Our results also highlight the different antimicrobial mechanisms exhibited by histone-derived peptides and suggest that histones may serve as a source of novel antimicrobial peptides with varied properties.

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

    Science.gov (United States)

    Zhao, Hongyan; Mu, Yu; Zhao, Baohua

    2009-07-01

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

  4. Antimicrobial Peptides, Infections and the Skin Barrier

    DEFF Research Database (Denmark)

    Clausen, Maja-Lisa; Agner, Tove

    2016-01-01

    The skin serves as a strong barrier protecting us from invading pathogens and harmful organisms. An important part of this barrier comes from antimicrobial peptides (AMPs), which are small peptides expressed abundantly in the skin. AMPs are produced in the deeper layers of the epidermis...

  5. Antimicrobial cyclic peptides for plant disease control.

    Science.gov (United States)

    Lee, Dong Wan; Kim, Beom Seok

    2015-03-01

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

  6. Antimicrobial Cyclic Peptides for Plant Disease Control

    Directory of Open Access Journals (Sweden)

    Dong Wan Lee

    2015-03-01

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

  7. Different effects of transcriptional regulators MarA, SoxS and Rob on susceptibility of Escherichia coli to cationic antimicrobial peptides (CAMPs): Rob-dependent CAMP induction of the marRAB operon.

    Science.gov (United States)

    Warner, Douglas M; Levy, Stuart B

    2010-02-01

    Cationic antimicrobial peptides (CAMPs), a component of the mammalian immune system, protect the host from bacterial infections. The roles of the Escherichia coli transcriptional regulators MarA, SoxS and Rob in susceptibility to these peptides were examined. Overexpression of marA, either in an antibiotic-resistant marR mutant or from a plasmid, decreased bacterial susceptibility to CAMPs. Overexpression of the soxS gene from a plasmid, which decreased susceptibility to antibiotics, unexpectedly caused no decrease in CAMP susceptibility; instead it produced increased susceptibility to different CAMPs. Deletion or overexpression of rob had little effect on CAMP susceptibility. The marRAB operon was upregulated when E. coli was incubated in sublethal amounts of CAMPs polymyxin B, LL-37 or human beta-defensin-1; however, this upregulation required Rob. Deletion of acrAB increased bacterial susceptibility to polymyxin B, LL-37 and human beta-defensin-1 peptides. Deletion of tolC yielded an even greater increase in susceptibility to these peptides and also led to increased susceptibility to human alpha-defensin-2. Inhibition of cellular proton-motive force increased peptide susceptibility for wild-type and acrAB deletion strains; however, it decreased susceptibility of tolC mutants. These findings demonstrate that CAMPs are both inducers of marA-mediated drug resistance through interaction with Rob and also substrates for efflux in E. coli. The three related transcriptional regulators show different effects on bacterial cell susceptibility to CAMPs.

  8. The role of salivary histatin and the human cathelicidin LL-37 in wound healing and innate immunity

    NARCIS (Netherlands)

    Oudhoff, M.J.; Blaauboer, M.E.; Nazmi, K.; Scheres, N.; Bolscher, J.G.M.; Veerman, E.C.I.

    2010-01-01

    Antimicrobial peptides are multifunctional in innate immunity and wound repair of multicellular organisms. We were the first to discover that histatins, a family of salivary antimicrobial peptides, enhance epithelial cell migration, suggesting a role in oral wound healing. It is unknown whether hist

  9. Computer-Aided Design of Antimicrobial Peptides

    DEFF Research Database (Denmark)

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

    2010-01-01

    chemical parameters with biological activities of the peptide, using statistical methods. In this review we will discuss two different in silico strategies of computer-aided antibacterial peptide design, a linear correlation model build as an extension of traditional principal component analysis (PCA......) and a non-linear artificial neural network model. Studies on structurally diverse peptides, have concluded that the PCA derived model are able to guide the antibacterial peptide design in a meaningful way, however requiring rather a high homology between the peptides in the test-set and the in silico...... library, to ensure a successful prediction. In contrast, the neural network model, though significantly less explored in relation to antimicrobial peptide design, has proven extremely promising, demonstrating impressive prediction success and ranking of random peptide libraries correlating well...

  10. LL-37, HNP-1, and HBD2/3 modulate the secretion of cytokines TNF-α, IL-6, IFN-γ, IL-10 and MMP1 in human primary cell cultures.

    Science.gov (United States)

    Medina Santos, Carlos Erik; López Hurtado, Carmen Nathaly; Rivas Santiago, Bruno; Gonzalez-Amaro, Roberto; Cataño Cañizales, Yolanda Guadalupe; Martínez Fierro, Margarita de la Luz; Enciso-Moreno, José Antonio; García Hernández, Mariana Haydee

    2016-09-01

    The aim of this study was to evaluate the effects of the LL-37, HNP-1 and HBD2/3 peptides on cytokine and MMP production in human polymorphonuclear cells, mononuclear cells and chondrocytes. The levels of cytokines in supernatants from mononuclear and polymorphonuclear cell cultures were measured with a cytometric bead array by flow cytometry. Likewise, the levels of metalloproteinase/MMP-1, 3, and 13 were measured in supernatants from chondrocyte cultures using an ELISA. The expression of RANKL on lymphocytes was analyzed by flow cytometry. We observed increased levels of TNF-α, IL-6 and IL-10 in mononuclear and polymorphonuclear cell cultures stimulated with HBD-2/3. We also observed increased levels of IFN-γ, IL-10, and IL-6 in mononuclear cell cultures stimulated with HNP-1, and increased IL-6 levels were observed in polymorphonuclear cell cultures exposed to HNP-1. We also found that the MMP-1 level increased in the chondrocyte cultures stimulated with HBD-3, whereas the MMP-1 level was decreased in cultures exposed to LL-37. The present report is the first study to determine that HNP-1and HBD2/3 promote the secretion of pro-inflammatory cytokines by polymorphonuclear and mononuclear cells and the secretion of MMP by chondrocytes, whereas LL-37 diminishes MMP1 secretion. Our results suggest that HBD-2/3 and HNP1 might play a pathological role in rheumatoid arthritis, while LL-37 might have a protective role.

  11. Antimicrobial peptides in innate immune responses.

    Science.gov (United States)

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

    2008-01-01

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

  12. Core–shell magnetic nanoparticles display synergistic antibacterial effects against Pseudomonas aeruginosa and Staphylococcus aureus when combined with cathelicidin LL-37 or selected ceragenins

    Science.gov (United States)

    Niemirowicz, Katarzyna; Piktel, Ewelina; Wilczewska, Agnieszka Z; Markiewicz, Karolina H; Durnaś, Bonita; Wątek, Marzena; Puszkarz, Irena; Wróblewska, Marta; Niklińska, Wiesława; Savage, Paul B; Bucki, Robert

    2016-01-01

    Core–shell magnetic nanoparticles (MNPs) are promising candidates in the development of new treatment methods against infections, including those caused by antibiotic-resistant pathogens. In this study, the bactericidal activity of human antibacterial peptide cathelicidin LL-37, synthetic ceragenins CSA-13 and CSA-131, and classical antibiotics vancomycin and colistin, against methicillin-resistant Staphylococcus aureus Xen 30 and Pseudomonas aeruginosa Xen 5, was assessed alone and in combination with core–shell MNPs. Fractional inhibitory concentration index and fractional bactericidal concentration index were determined by microdilution methods. The potential of combined therapy using nanomaterials and selected antibiotics was confirmed using chemiluminescence measurements. Additionally, the ability of tested agents to prevent bacterial biofilm formation was evaluated using crystal violet staining. In most conditions, synergistic or additive effects were observed when combinations of core–shell MNPs with ceragenins or classical antibiotics were used. Our study revealed that a mixture of membrane-active agents such as LL-37 peptide or ceragenin CSA-13 with MNPs potentialized their antibacterial properties and might be considered as a method of delaying and overcoming bacterial drug resistance. PMID:27799768

  13. 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 <200-nm bilayer vesicles composed of anionic and neutral lipids as well as cholesterol. Vesicle disruption, or peptide potency, was monitored with a sensitive fluorescence leakage assay. Detailed molecular information on peptidemembrane interactions and peptide structure was further gained through vibrational spectroscopy combined with circular dichroism. Finally, steady-state fluorescence experiments yielded insight into the local environment of native or engineered tryptophan residues in melittin and human cathelicidin embedded in bilayer vesicles. Collectively, our results provide clues to the functional structures of the engineered and toxic peptides and may impact the design of synthetic antibiotic peptides that can be used against the growing number of antibiotic-resistant pathogens.

  14. Antimicrobial Peptides in Innate Immunity against Mycobacteria.

    Science.gov (United States)

    Shin, Dong-Min; Jo, Eun-Kyeong

    2011-10-01

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

  15. Antimicrobial peptides : Experimental prevention of osteomyelitis

    NARCIS (Netherlands)

    Stallmann, H.P.

    2007-01-01

    The first chapter introduces the main concepts of this manuscript: osteomyelitis (bone infection), bacterial resistance and antimicrobial peptides (AMPs). As part of a solution to the first two problems, AMPs were investigated for the experimental prevention of infection. The first chapter introduc

  16. An enhancer peptide for membrane-disrupting antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    Zhang Hong

    2010-02-01

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

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

    Science.gov (United States)

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

    2001-06-01

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

  18. Peptide consensus sequence determination for the enhancement of the antimicrobial activity and selectivity of antimicrobial peptides

    Science.gov (United States)

    Almaaytah, Ammar; Ajingi, Ya’u; Abualhaijaa, Ahmad; Tarazi, Shadi; Alshar’i, Nizar; Al-Balas, Qosay

    2017-01-01

    The rise of multidrug-resistant bacteria is causing a serious threat to the world’s human population. Recent reports have identified bacterial strains displaying pan drug resistance against antibiotics and generating fears among medical health specialists that humanity is on the dawn of entering a post-antibiotics era. Global research is currently focused on expanding the lifetime of current antibiotics and the development of new antimicrobial agents to tackle the problem of antimicrobial resistance. In the present study, we designed a novel consensus peptide named “Pepcon” through peptide consensus sequence determination among members of a highly homologous group of scorpion antimicrobial peptides. Members of this group were found to possess moderate antimicrobial activity with significant toxicity against mammalian cells. The aim of our design method was to generate a novel peptide with an enhanced antimicrobial potency and selectivity against microbial rather than mammalian cells. The results of our study revealed that the consensus peptide displayed potent antibacterial activities against a broad range of Gram-positive and Gram-negative bacteria. Our membrane permeation studies displayed that the peptide efficiently induced membrane damage and consequently led to cell death through the process of cell lysis. The microbial DNA binding assay of the peptide was found to be very weak suggesting that the peptide is not targeting the microbial DNA. Pepcon induced minimal cytotoxicity at the antimicrobial concentrations as the hemolytic activity was found to be zero at the minimal inhibitory concentrations (MICs). The results of our study demonstrate that the consensus peptide design strategy is efficient in generating peptides. PMID:28096686

  19. 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.

  20. 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.

  1. Biologically Active and Antimicrobial Peptides from Plants

    Directory of Open Access Journals (Sweden)

    Carlos E. Salas

    2015-01-01

    Full Text Available Bioactive peptides are part of an innate response elicited by most living forms. In plants, they are produced ubiquitously in roots, seeds, flowers, stems, and leaves, highlighting their physiological importance. While most of the bioactive peptides produced in plants possess microbicide properties, there is evidence that they are also involved in cellular signaling. Structurally, there is an overall similarity when comparing them with those derived from animal or insect sources. The biological action of bioactive peptides initiates with the binding to the target membrane followed in most cases by membrane permeabilization and rupture. Here we present an overview of what is currently known about bioactive peptides from plants, focusing on their antimicrobial activity and their role in the plant signaling network and offering perspectives on their potential application.

  2. Therapeutic antimicrobial peptides may compromise natural immunity.

    Science.gov (United States)

    Habets, Michelle G J L; Brockhurst, Michael A

    2012-06-23

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

  3. Antimicrobial Peptides with Differential Bacterial Binding Characteristics

    Science.gov (United States)

    2013-03-01

    Moderate CA-MA [22] KWKLFKKIGIGKFLHLAKKF Strong Strong HP-ME [23] AKKVFKRLGIGAVLKVLTTG Strong Strong Strong activity: MIC ≤ 10 µM; Moderate...activity: MIC = 10-100 µM; Weak activity: MIC ≥ 100 µM; n.d. = no data available; qual. = qualitative assessment of activity only. 4...Andersson, M., Jornvall, H., Mutt, V., & Boman, H. G. (1989). Antimicrobial peptides from pig intestine: Isolation of a mammalian cecropin

  4. Peptide design for antimicrobial and immunomodulatory applications.

    Science.gov (United States)

    Haney, Evan F; Hancock, Robert E W

    2013-11-01

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

  5. Haemophilus ducreyi is resistant to human antimicrobial peptides.

    Science.gov (United States)

    Mount, Kristy L B; Townsend, Carisa A; Bauer, Margaret E

    2007-09-01

    We examined the susceptibility of Haemophilus ducreyi to antimicrobial peptides likely to be encountered in vivo during human infection. H. ducreyi was significantly more resistant than Escherichia coli to the bactericidal effects of all peptides tested. Class I and II H. ducreyi strains exhibited similar levels of resistance to antimicrobial peptides.

  6. Antimicrobial activity of human salivary mucin-derived peptides

    NARCIS (Netherlands)

    Wei, G.

    2008-01-01

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

  7. Activity of Cathelicidin Peptides against Simkania negevensis.

    Science.gov (United States)

    Donati, Manuela; Di Francesco, Antonietta; Di Paolo, Maria; Fiani, Natascia; Benincasa, Monica; Gennaro, Renato; Nardini, Paola; Foschi, Claudio; Cevenini, Roberto

    2011-01-01

    The in vitro activity of six cathelicidin peptides against the reference strain Z of Simkania negevensis was investigated. Five peptides-PG-1, Bac7, SMAP-29, BMAP-27, and BMAP-28-proved to be active at very low concentrations (1 to 0.1 μg/mL), while LL-37 cathelicidin was ineffective even at a concentration of 100 μg/mL. In comparison to chlamydiae, S. negevensis proved to be more susceptible to the antimicrobial peptides tested.

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    of LL-37, PR-39 or wheat germ histones. WGS and proteomic analysis by MS were used to identify the molecular mechanism associated with increased tolerance of AMPs. AMP-resistant mutants were characterized by measuring in vitro fitness, AMP and antibiotic susceptibility, and virulence in a mouse model...... of sepsis. Results: AMP-resistant Staphylococcus aureus mutants often displayed little to no fitness cost and caused invasive disease in mice. Further, this phenotype coincided with diminished susceptibility to both clinically prescribed antibiotics and human defence peptides. Conclusions: These findings...... suggest that therapeutic use of AMPs could select for virulent mutants with crossresistance to human innate immunity as well as antibiotic therapy. Thus, therapeutic use of AMPs and the implications of cross-resistance need to be carefully monitored and evaluated....

  9. Identification of antimicrobial peptides by using eigenvectors.

    Science.gov (United States)

    Polanco, Carlos

    2016-01-01

    Antibacterial peptides are subject to broad research due to their potential application and the benefit they can provide for a wide range of diseases. In this work, a mathematical-computational method, called the Polarity Vector Method, is introduced that has a high discriminative level (>70%) to identify peptides associated with Gram (-) bacteria, Gram (+) bacteria, cancer cells, fungi, insects, mammalian cells, parasites, and viruses, taken from the Antimicrobial Peptides Database. This supervised method uses only eigenvectors from the incident polar matrix of the group studied. It was verified with a comparative study with another extensively verified method developed previously by our team, the Polarity Index Method. The number of positive hits of both methods was up to 98% in all the tests conducted.

  10. Peptides with Dual Antimicrobial and Anticancer Activities

    Science.gov (United States)

    Felício, Mário R.; Silva, Osmar N.; Gonçalves, Sônia; Santos, Nuno C.; Franco, Octávio L.

    2017-01-01

    In recent years, the number of people suffering from cancer and multi-resistant infections has increased, such that both diseases are already seen as current and future major causes of death. Moreover, chronic infections are one of the main causes of cancer, due to the instability in the immune system that allows cancer cells to proliferate. Likewise, the physical debility associated with cancer or with anticancer therapy itself often paves the way for opportunistic infections. It is urgent to develop new therapeutic methods, with higher efficiency and lower side effects. Antimicrobial peptides (AMPs) are found in the innate immune system of a wide range of organisms. Identified as the most promising alternative to conventional molecules used nowadays against infections, some of them have been shown to have dual activity, both as antimicrobial and anticancer peptides (ACPs). Highly cationic and amphipathic, they have demonstrated efficacy against both conditions, with the number of nature-driven or synthetically designed peptides increasing year by year. With similar properties, AMPs that can also act as ACPs are viewed as future chemotherapeutic drugs, with the advantage of low propensity to resistance, which started this paradigm in the pharmaceutical market. These peptides have already been described as molecules presenting killing mechanisms at the membrane level, but also acting toward intracellular targets, which increases their success compartively to one-target specific drugs. This review will approach the desirable characteristics of small peptides that demonstrated dual activity against microbial infections and cancer, as well as the peptides engaged in clinical trials. PMID:28271058

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

    Science.gov (United States)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2009-11-01

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

  13. 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.

  14. Anti-antimicrobial peptides: folding-mediated host defense antagonists.

    Science.gov (United States)

    Ryan, Lloyd; Lamarre, Baptiste; Diu, Ting; Ravi, Jascindra; Judge, Peter J; Temple, Adam; Carr, Matthew; Cerasoli, Eleonora; Su, Bo; Jenkinson, Howard F; Martyna, Glenn; Crain, Jason; Watts, Anthony; Ryadnov, Maxim G

    2013-07-12

    Antimicrobial or host defense peptides are innate immune regulators found in all multicellular organisms. Many of them fold into membrane-bound α-helices and function by causing cell wall disruption in microorganisms. Herein we probe the possibility and functional implications of antimicrobial antagonism mediated by complementary coiled-coil interactions between antimicrobial peptides and de novo designed antagonists: anti-antimicrobial peptides. Using sequences from native helical families such as cathelicidins, cecropins, and magainins we demonstrate that designed antagonists can co-fold with antimicrobial peptides into functionally inert helical oligomers. The properties and function of the resulting assemblies were studied in solution, membrane environments, and in bacterial culture by a combination of chiroptical and solid-state NMR spectroscopies, microscopy, bioassays, and molecular dynamics simulations. The findings offer a molecular rationale for anti-antimicrobial responses with potential implications for antimicrobial resistance.

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

    Science.gov (United States)

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

    2013-04-01

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

  16. Plant antimicrobial peptides as potential anticancer agents.

    Science.gov (United States)

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

    2015-01-01

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

  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. Antimicrobial beta-peptides and alpha-peptoids

    DEFF Research Database (Denmark)

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

    2011-01-01

    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...

  19. 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.

  20. Quantitative studies of antimicrobial peptide-lipid membrane interactions

    DEFF Research Database (Denmark)

    Kristensen, Kasper

    into such novel therapeutics. However, limited understanding of the mechanisms underlying microbicidal activity of antimicrobial peptides has slowed down this development. A central step toward understanding the microbicidal mechanisms of action of antimicrobial peptides is to understand the mechanisms by which......The increasing occurrence of multi-drug-resistant bacteria poses a serious threat to modern society. Therefore, novel types of anti-infective therapeutics are highly warranted. Antimicrobial peptides are a class of naturally occurring host-defense molecules that potentially might be developed...... antimicrobial peptides interact with phospholipid membranes. Motivated by that fact, the scope of this thesis is to study these antimicrobial peptide-lipid membrane interactions. In particular, we attempt to study these interactions with a quantitative approach. For that purpose, we consider the three...

  1. Activity of Cathelicidin Peptides against Simkania negevensis

    Directory of Open Access Journals (Sweden)

    Manuela Donati

    2011-01-01

    Full Text Available The in vitro activity of six cathelicidin peptides against the reference strain Z of Simkania negevensis was investigated. Five peptides—PG-1, Bac7, SMAP-29, BMAP-27, and BMAP-28—proved to be active at very low concentrations (1 to 0.1 μg/mL, while LL-37 cathelicidin was ineffective even at a concentration of 100 μg/mL. In comparison to chlamydiae, S. negevensis proved to be more susceptible to the antimicrobial peptides tested.

  2. Immunomodulatory effects of anti-microbial peptides.

    Science.gov (United States)

    Otvos, Laszlo

    2016-09-01

    Anti-microbial peptides (AMPs) were originally thought to exert protecting actions against bacterial infection by disintegrating bacterial membranes. Upon identification of internal bacterial targets, the view changed and moved toward inhibition of prokaryote-specific biochemical processes. However, the level of none of these activities can explain the robust efficacy of some of these peptides in animal models of systemic and cutaneous infections. A rapidly growing panel of reports suggests that AMPs, now called host-defense peptides (HDPs), act through activating the immune system of the host. This includes recruitment and activation of macrophages and mast cells, inducing chemokine production and altering NF-κB signaling processes. As a result, both pro- and anti-inflammatory responses are elevated together with activation of innate and adaptive immunity mechanisms, wound healing, and apoptosis. HDPs sterilize the systemic circulation and local injury sites significantly more efficiently than pure single-endpoint in vitro microbiological or biochemical data would suggest and actively aid recovering from tissue damage after or even without bacterial infections. However, the multiple and, often opposing, immunomodulatory functions of HDPs require exceptional care in therapeutic considerations.

  3. pH Dependent Antimicrobial Peptides and Proteins, Their Mechanisms of Action and Potential as Therapeutic Agents

    Directory of Open Access Journals (Sweden)

    Erum Malik

    2016-11-01

    Full Text Available Antimicrobial peptides (AMPs are potent antibiotics of the innate immune system that have been extensively investigated as a potential solution to the global problem of infectious diseases caused by pathogenic microbes. A group of AMPs that are increasingly being reported are those that utilise pH dependent antimicrobial mechanisms, and here we review research into this area. This review shows that these antimicrobial molecules are produced by a diverse spectrum of creatures, including vertebrates and invertebrates, and are primarily cationic, although a number of anionic examples are known. Some of these molecules exhibit high pH optima for their antimicrobial activity but in most cases, these AMPs show activity against microbes that present low pH optima, which reflects the acidic pH generally found at their sites of action, particularly the skin. The modes of action used by these molecules are based on a number of major structure/function relationships, which include metal ion binding, changes to net charge and conformational plasticity, and primarily involve the protonation of histidine, aspartic acid and glutamic acid residues at low pH. The pH dependent activity of pore forming antimicrobial proteins involves mechanisms that generally differ fundamentally to those used by pH dependent AMPs, which can be described by the carpet, toroidal pore and barrel-stave pore models of membrane interaction. A number of pH dependent AMPs and antimicrobial proteins have been developed for medical purposes and have successfully completed clinical trials, including kappacins, LL-37, histatins and lactoferrin, along with a number of their derivatives. Major examples of the therapeutic application of these antimicrobial molecules include wound healing as well as the treatment of multiple cancers and infections due to viruses, bacteria and fungi. In general, these applications involve topical administration, such as the use of mouth washes, cream formulations

  4. pH Dependent Antimicrobial Peptides and Proteins, Their Mechanisms of Action and Potential as Therapeutic Agents

    Science.gov (United States)

    Malik, Erum; Dennison, Sarah R.; Harris, Frederick; Phoenix, David A.

    2016-01-01

    Antimicrobial peptides (AMPs) are potent antibiotics of the innate immune system that have been extensively investigated as a potential solution to the global problem of infectious diseases caused by pathogenic microbes. A group of AMPs that are increasingly being reported are those that utilise pH dependent antimicrobial mechanisms, and here we review research into this area. This review shows that these antimicrobial molecules are produced by a diverse spectrum of creatures, including vertebrates and invertebrates, and are primarily cationic, although a number of anionic examples are known. Some of these molecules exhibit high pH optima for their antimicrobial activity but in most cases, these AMPs show activity against microbes that present low pH optima, which reflects the acidic pH generally found at their sites of action, particularly the skin. The modes of action used by these molecules are based on a number of major structure/function relationships, which include metal ion binding, changes to net charge and conformational plasticity, and primarily involve the protonation of histidine, aspartic acid and glutamic acid residues at low pH. The pH dependent activity of pore forming antimicrobial proteins involves mechanisms that generally differ fundamentally to those used by pH dependent AMPs, which can be described by the carpet, toroidal pore and barrel-stave pore models of membrane interaction. A number of pH dependent AMPs and antimicrobial proteins have been developed for medical purposes and have successfully completed clinical trials, including kappacins, LL-37, histatins and lactoferrin, along with a number of their derivatives. Major examples of the therapeutic application of these antimicrobial molecules include wound healing as well as the treatment of multiple cancers and infections due to viruses, bacteria and fungi. In general, these applications involve topical administration, such as the use of mouth washes, cream formulations and hydrogel

  5. Effect of Fatty Acid Conjugation on Antimicrobial Peptide Activity

    Science.gov (United States)

    2004-12-01

    killing mechanism of antimicrobial peptides makes them an interesting alternative to traditional antibiotics, as target bacteria may be less able...C14-AKK and C16-AKK to within a 7% error are 220 and 16mM respectively. Since amphipathicity is requisite for antimicrobial action KAK is not...Schnaare, 2000: Antimicrobial evaluation of N-alkyl betaines and N-alkyl-N,N-dimethylamine oxides with variations in chain length. Antimicrobial Agents

  6. Coleopteran Antimicrobial Peptides: Prospects for Clinical Applications

    Directory of Open Access Journals (Sweden)

    Monde Ntwasa

    2012-01-01

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

  7. 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.

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

    Science.gov (United States)

    Beisswenger, Christoph; Bals, Robert

    2005-06-01

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

  9. Innate Defense Regulator Peptide 1018 in Wound Healing and Wound Infection

    DEFF Research Database (Denmark)

    Steinstraesser, Lars; Hirsch, Tobias; Schulte, Matthias

    2012-01-01

    Innate defense regulators (IDRs) are synthetic immunomodulatory versions of natural host defense peptides (HDP). IDRs mediate protection against bacterial challenge in the absence of direct antimicrobial activity, representing a novel approach to anti-infective and anti-inflammatory therapy......-1018 in vitro. Further, we investigated the efficacy of IDR-1018 in diabetic and non-diabetic wound healing models. In all experiments, IDR-1018 was compared to the human HDP LL-37 and HDP-derived wound healing peptide HB-107. IDR-1018 was significantly less cytotoxic in vitro as compared to either LL......-37 or HB-107. Furthermore, administration of IDR-1018 resulted in a dose-dependent increase in fibroblast cellular respiration. In vivo, IDR-1018 demonstrated significantly accelerated wound healing in S. aureus infected porcine and non-diabetic but not in diabetic murine wounds. However...

  10. Three new antimicrobial peptides from the scorpion Pandinus imperator.

    Science.gov (United States)

    Zeng, Xian-Chun; Zhou, Lingli; Shi, Wanxia; Luo, Xuesong; Zhang, Lei; Nie, Yao; Wang, Jinwei; Wu, Shifen; Cao, Bin; Cao, Hanjun

    2013-07-01

    Three novel cysteine-free venom peptides, which were referred to as Pantinin-1, Pantinin-2 and Pantinin-3, respectively, have been identified from the scorpion Pandinus imperator by cDNA cloning strategy. The precursor of each peptide consists of a signal peptide, a mature peptide with no disulfide bridges, and an acidic propeptide with a typical processing signal. Each of the three peptides is an α-helical, cationic and amphipathic molecule with 13 or 14 amino acid residues. Their amino acid sequences are homologous to those of some 13-mer antimicrobial peptides isolated from scorpions. Antimicrobial assay showed that all the three peptides possess relatively strong activities against Gram-positive bacteria and a fungus, but have very weak antimicrobial activities against Gram-negative bacteria. Toxicity assay showed that the three peptides exhibit very low or mild hemolytic activities against human red blood cells. It is interesting to see that Pantinin-3 is able to potently inhibit the growth of vancomycin-resistant Enterococcus (VRE) S13, a pathogen that can cause a number of human infections; this suggests that Pantinin-3 has great potential to be applied in the treatment of VRE infections. Our findings gain new insights into the structure/function relationships of the small linear cationic antimicrobial peptides from scorpions, and provide new templates for designing of antimicrobial agents targeting antibiotic-resistant pathogenic bacteria.

  11. 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.

  12. Antimicrobial and immunomodulatory activities of PR-39 derived peptides.

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    Edwin J A Veldhuizen

    Full Text Available The porcine cathelicidin PR-39 is a host defence peptide that plays a pivotal role in the innate immune defence of the pig against infections. Besides direct antimicrobial activity, it is involved in immunomodulation, wound healing and several other biological processes. In this study, the antimicrobial- and immunomodulatory activity of PR-39, and N- and C-terminal derivatives of PR-39 were tested. PR-39 exhibited an unexpected broad antimicrobial spectrum including several Gram positive strains such as Bacillus globigii and Enterococcus faecalis. Of organisms tested, only Staphylococcus aureus was insensitive to PR-39. Truncation of PR-39 down to 15 (N-terminal amino acids did not lead to major loss of activity, while peptides corresponding to the C-terminal part of PR-39 were hampered in their antimicrobial activity. However, shorter peptides were all much more sensitive to inhibition by salt. Active peptides induced ATP leakage and loss of membrane potential in Bacillus globigii and Escherichia coli, indicating a lytic mechanism of action for these peptides. Finally, only the mature peptide was able to induce IL-8 production in porcine macrophages, but some shorter peptides also had an effect on TNF-α production showing differential regulation of cytokine induction by PR-39 derived peptides. None of the active peptides showed high cytotoxicity highlighting the potential of these peptides for use as an alternative to antibiotics.

  13. Antimicrobial peptides from the hemolymph of the prawn Macrobrachium rosenbergii

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    Samuthirapandian Ravichandran

    2010-03-01

    Full Text Available The study was carried out to find the antimicrobial activity of hemolymph of Macrobrachium rosenbergii and to evaluate the antimicrobial compounds. The highest inhibition against Staphylococcus aureus, Lactobacillus vulgaris and Klebsiella pneumonia (12 mm and antifungal activity was observed only against Fusarium moniliforme (11 mm. Antimicrobial peptide was characterized in molecular size ranging from 22 to 91KDa with antimicrobial activity against various infectious pathogens. Hemolymph plays a vital role in the disease prevention in crustaceans and there is no report on antimicrobial activities of the prawn M. rosenbergii.

  14. The role of antimicrobial peptides in chronic inflammatory skin diseases

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    Majewski, Sławomir

    2016-01-01

    Antimicrobial peptides (AMPs) are effector molecules of the innate immune system of the skin. They present an activity against a broad spectrum of Gram-positive and Gram-negative bacteria as well as some fungi, parasites and enveloped viruses. Several inflammatory skin diseases including psoriasis, atopic dermatitis, acne vulgaris and rosacea are characterized by a dysregulated expression of AMPs. Antimicrobial peptides are excessively produced in lesional psoriatic scales or rosacea in contrast to the atopic skin that shows lower AMP levels when compared with psoriasis. The importance of the AMPs contribution to host immunity is indisputable as alterations in the antimicrobial peptide expression have been associated with various pathologic processes. This review discusses the biology and clinical relevance of antimicrobial peptides expressed in the skin and their role in the pathogenesis of inflammatory skin diseases. PMID:26985172

  15. Role of Antimicrobial Peptides in Inflammatory Bowel Disease

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    Stefan Vordenbäumen

    2011-11-01

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

  16. ANTIMICROBIAL PEPTIDES: AN EFFECTIVE ALTERNATIVE FOR ANTIBIOTIC THERAPY

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    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.

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

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    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.

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

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

    2013-07-01

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

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

    Science.gov (United States)

    Li, Yifeng

    2009-12-18

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

  20. Use of Peptide Libraries for Identification and Optimization of Novel Antimicrobial Peptides.

    Science.gov (United States)

    Ashby, Martin; Petkova, Asya; Gani, Jurnorain; Mikut, Ralf; Hilpert, Kai

    2017-01-01

    The increasing rates of resistance among bacteria and to a lesser extent fungi have resulted in an urgent need to find new molecules that hold therapeutic promise against multidrug-resistant strains. Antimicrobial peptides have proven very effective against a variety of multidrug-resistant bacteria. Additionally, the low levels of resistance reported towards these molecules are an attractive feature for antimicrobial drug development. Here we summarise information on diverse peptide libraries used to discover or to optimize antimicrobial peptides. Chemical synthesized peptide libraries, for example split and mix method, tea bag method, multi-pin method and cellulose spot method are discussed. In addition biological peptide library screening methods are summarized, like phage display, bacterial display, mRNA-display and ribosomal display. A few examples are given for small peptide libraries, which almost exclusively follow a rational design of peptides of interest rather than a combinatorial approach.

  1. 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

  2. Defense at the lung lining: antifungal activities of SP-D and LL-37

    NARCIS (Netherlands)

    Ordonez, Soledad R

    2016-01-01

    Host defense proteins and peptides are part of the innate immune system of the lung. They constitute one of the first defenses against fungal pathogens during inhalation. Discerning how these molecular defenses act in concert to prevent infection in a healthy lung has proven to be difficult, due to

  3. Archetypal tryptophan-rich antimicrobial peptides: properties and applications.

    Science.gov (United States)

    Shagaghi, Nadin; Palombo, Enzo A; Clayton, Andrew H A; Bhave, Mrinal

    2016-02-01

    Drug-resistant microorganisms ('superbugs') present a serious challenge to the success of antimicrobial treatments. Subsequently, there is a crucial need for novel bio-control agents. Many antimicrobial peptides (AMPs) show a broad-spectrum activity against bacteria, fungi or viruses and are strong candidates to complement or substitute current antimicrobial agents. Some AMPs are also effective against protozoa or cancer cells. The tryptophan (Trp)-rich peptides (TRPs) are a subset of AMPs that display potent antimicrobial activity, credited to the unique biochemical properties of tryptophan that allow it to insert into biological membranes. Further, many Trp-rich AMPs cross bacterial membranes without compromising their integrity and act intracellularly, suggesting interactions with nucleic acids and enzymes. In this work, we overview some archetypal TRPs derived from natural sources, i.e., indolicidin, tritrpticin and lactoferricin, summarising their biochemical properties, structures, antimicrobial activities, mechanistic studies and potential applications.

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

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    Alice P. McCloskey

    2014-10-01

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

  5. The innate defense antimicrobial peptides hBD3 and RNase7 are induced in human umbilical vein endothelial cells by classical inflammatory cytokines but not Th17 cytokines.

    Science.gov (United States)

    Burgey, Christine; Kern, Winfried V; Römer, Winfried; Sakinc, Türkan; Rieg, Siegbert

    2015-05-01

    Antimicrobial peptides are multifunctional effector molecules of innate immunity. In this study we investigated whether endothelial cells actively contribute to innate defense mechanisms by expression of antimicrobial peptides. We therefore stimulated human umbilical vein endothelial cells (HUVEC) with inflammatory cytokines, Th17 cytokines, heat-inactivated bacteria, bacterial conditioned medium (BCM) of Staphylococcus aureus and Streptococcus sanguinis, and lipoteichoic acid (LTA). Stimulation with single cytokines induced discrete expression of human β-defensin 3 (hBD3) by IFN-γ or IL-1β and of ribonuclease 7 (RNase7) by TNF-α without any effects on LL-37 gene expression. Stronger hBD3 and RNase7 induction was observed after combined stimulation with IL-1β, TNF-α and IFN-γ and was confirmed by high hBD3 and RNase7 peptide levels in cell culture supernatants. In contrast, Th17 cytokines or stimulation with LTA did not result in AMP production. Moreover, only BCM of an invasive S. aureus bacteremia isolate induced hBD3 in HUVEC. We conclude that endothelial cells actively contribute to prevent dissemination of pathogens at the blood-tissue-barrier by production of AMPs that exhibit microbicidal and immunomodulatory functions. Further investigations should focus on tissue-specific AMP induction in different endothelial cell types, on pathogen-specific induction patterns and potentially involved pattern-recognition receptors of endothelial cells.

  6. Antimicrobial protein and Peptide concentrations and activity in human breast milk consumed by preterm infants at risk of late-onset neonatal sepsis.

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    Stephanie Trend

    Full Text Available OBJECTIVE: We investigated the levels and antimicrobial activity of antimicrobial proteins and peptides (AMPs in breast milk consumed by preterm infants, and whether deficiencies of these factors were associated with late-onset neonatal sepsis (LOS, a bacterial infection that frequently occurs in preterm infants in the neonatal period. STUDY DESIGN: Breast milk from mothers of preterm infants (≤ 32 weeks gestation was collected on days 7 (n = 88 and 21 (n = 77 postpartum. Concentrations of lactoferrin, LL-37, beta-defensins 1 and 2, and alpha-defensin 5 were measured by enzyme-linked immunosorbent assay. The antimicrobial activity of breast milk samples against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Streptococcus agalactiae was compared to the activity of infant formula, alone or supplemented with physiological levels of AMPs. Samples of breast milk fed to infants with and without subsequent LOS were compared for levels of AMPs and inhibition of bacterial growth. RESULTS: Levels of most AMPs and antibacterial activity in preterm breast milk were higher at day 7 than at day 21. Lactoferrin was the only AMP that limited pathogen growth >50% when added to formula at a concentration equivalent to that present in breast milk. Levels of AMPs were similar in the breast milk fed to infants with and without LOS, however, infants who developed LOS consumed significantly less breast milk and lower doses of milk AMPs than those who were free from LOS. CONCLUSIONS: The concentrations of lactoferrin and defensins in preterm breast milk have antimicrobial activity against common neonatal pathogens.

  7. Improved methods for classification, prediction, and design of antimicrobial peptides.

    Science.gov (United States)

    Wang, Guangshun

    2015-01-01

    Peptides with diverse amino acid sequences, structures, and functions are essential players in biological systems. The construction of well-annotated databases not only facilitates effective information management, search, and mining but also lays the foundation for developing and testing new peptide algorithms and machines. The antimicrobial peptide database (APD) is an original construction in terms of both database design and peptide entries. The host defense antimicrobial peptides (AMPs) registered in the APD cover the five kingdoms (bacteria, protists, fungi, plants, and animals) or three domains of life (bacteria, archaea, and eukaryota). This comprehensive database ( http://aps.unmc.edu/AP ) provides useful information on peptide discovery timeline, nomenclature, classification, glossary, calculation tools, and statistics. The APD enables effective search, prediction, and design of peptides with antibacterial, antiviral, antifungal, antiparasitic, insecticidal, spermicidal, anticancer activities, chemotactic, immune modulation, or antioxidative properties. A universal classification scheme is proposed herein to unify innate immunity peptides from a variety of biological sources. As an improvement, the upgraded APD makes predictions based on the database-defined parameter space and provides a list of the sequences most similar to natural AMPs. In addition, the powerful pipeline design of the database search engine laid a solid basis for designing novel antimicrobials to combat resistant superbugs, viruses, fungi, or parasites. This comprehensive AMP database is a useful tool for both research and education.

  8. 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.

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

    Science.gov (United States)

    Auvynet, Constance; Rosenstein, Yvonne

    2009-11-01

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

  10. Mechanisms and Biological Costs of Bacterial Resistance to Antimicrobial Peptides

    OpenAIRE

    Lofton Tomenius, Hava

    2016-01-01

    The global increasing problem of antibiotic resistance necessarily drives the pursuit and discovery of new antimicrobial agents. Antimicrobial peptides (AMPs) initially seemed like promising new drug candidates. Already members of the innate immune system, it was assumed that they would be bioactive and non-toxic. Their common trait for fundamental, non-specific mode of action also seemed likely to reduce resistance development. In this thesis, we demonstrate the ease with which two species o...

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

    Science.gov (United States)

    Wang, Yi-Peng; Lai, Ren

    2010-02-01

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

  12. Insights into Antimicrobial Peptides from Spiders and Scorpions.

    Science.gov (United States)

    Wang, Xiuqing; Wang, Guangshun

    2016-01-01

    The venoms of spiders and scorpions contain a variety of chemical compounds. Antimicrobial peptides (AMPs) from these organisms were first discovered in the 1990s. As of May 2015, there were 42 spider's and 63 scorpion's AMPs in the Antimicrobial Peptide Database (http://aps.unmc.edu/AP). These peptides have demonstrated broad or narrow-spectrum activities against bacteria, fungi, viruses, and parasites. In addition, they can be toxic to cancer cells, insects and erythrocytes. To provide insight into such an activity spectrum, this article discusses the discovery, classification, structure and activity relationships, bioinformatics analysis, and potential applications of spider and scorpion AMPs. Our analysis reveals that, in the case of linear peptides, spiders use both glycine-rich and helical peptide models for defense, whereas scorpions use two distinct helical peptide models with different amino acid compositions to exert the observed antimicrobial activities and hemolytic toxicity. Our structural bioinformatics study improves the knowledge in the field and can be used to design more selective peptides to combat tumors, parasites, and viruses.

  13. Selective antimicrobial activity and mode of action of adepantins, glycine-rich peptide antibiotics based on anuran antimicrobial peptide sequences.

    Science.gov (United States)

    Ilić, Nada; Novković, Mario; Guida, Filomena; Xhindoli, Daniela; Benincasa, Monica; Tossi, Alessandro; Juretić, Davor

    2013-03-01

    A challenge when designing membrane-active peptide antibiotics with therapeutic potential is how to ensure a useful antibacterial activity whilst avoiding unacceptable cytotoxicity for host cells. Understanding their mode of interaction with membranes and the reasons underlying their ability to distinguish between bacterial and eukaryotic cytoplasmic cells is crucial for any rational attempt to improve this selectivity. We have approached this problem by analysing natural helical antimicrobial peptides of anuran origin, using a structure-activity database to determine an antimicrobial selectivity index (SI) relating the minimal inhibitory concentration against Escherichia coli to the haemolytic activity (SI=HC(50)/MIC). A parameter that correlated strongly with SI, derived from the lengthwise asymmetry of the peptides' hydrophobicity (sequence moment), was then used in the "Designer" algorithm to propose novel, highly selective peptides. Amongst these are the 'adepantins', peptides rich in glycines and lysines that are highly selective for Gram-negative bacteria, have an exceptionally low haemolytic activity, and are less than 50% homologous to any other natural or synthetic antimicrobial peptide. In particular, they showed a very high SI for E. coli (up to 400) whilst maintaining an antimicrobial activity in the 0.5-4μM range. Experiments with monomeric, dimeric and fluorescently labelled versions of the adepantins, using different bacterial strains, host cells and model membrane systems provided insight into their mechanism of action.

  14. Discovering new in silico tools for antimicrobial peptide prediction.

    Science.gov (United States)

    Torrent, Marc; Nogués, M Victòria; Boix, Ester

    2012-08-01

    Antimicrobial peptides (AMPs) are important effectors of the innate immune system and play a vital role in the prevention of infections. Due to the increased emergence of new antibiotic-resistant bacteria, new drugs are constantly under investigation. AMPs in particular are recognized as promising candidates because of their modularity and wide antimicrobial spectrum. However, the mechanisms of action of AMPs, as well as their structure-activity relationships, are not completely understood. AMPs display no conserved three-dimensional structure and poor sequence conservation, which hinders rational design. Several bioinformatics tools have been developed to generate new templates with appealing antimicrobial properties with the aim of finding highly active peptide compounds with low cytotoxicity. The current tools reviewed here allow for the prediction and design of new active peptides with reasonable accuracy. However, a reliable method to assess the antimicrobial activity of AMPs has not yet been developed. The standardization of procedures to experimentally evaluate the antimicrobial activity of AMPs, together with the constant growth of current well-established databases, may allow for the future development of new bioinformatics tools to accurately predict antimicrobial activity.

  15. NMR and computational data of two novel antimicrobial peptides

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    Lucia Falcigno

    2016-09-01

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

  16. Azithromycin Synergizes with Cationic Antimicrobial Peptides to Exert Bactericidal and Therapeutic Activity Against Highly Multidrug-Resistant Gram-Negative Bacterial Pathogens

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    Leo Lin

    2015-07-01

    Full Text Available Antibiotic resistance poses an increasingly grave threat to the public health. Of pressing concern, rapid spread of carbapenem-resistance among multidrug-resistant (MDR Gram-negative rods (GNR is associated with few treatment options and high mortality rates. Current antibiotic susceptibility testing guiding patient management is performed in a standardized manner, identifying minimum inhibitory concentrations (MIC in bacteriologic media, but ignoring host immune factors. Lacking activity in standard MIC testing, azithromycin (AZM, the most commonly prescribed antibiotic in the U.S., is never recommended for MDR GNR infection. Here we report a potent bactericidal action of AZM against MDR carbapenem-resistant isolates of Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. This pharmaceutical activity is associated with enhanced AZM cell penetration in eukaryotic tissue culture media and striking multi-log-fold synergies with host cathelicidin antimicrobial peptide LL-37 or the last line antibiotic colistin. Finally, AZM monotherapy exerts clear therapeutic effects in murine models of MDR GNR infection. Our results suggest that AZM, currently ignored as a treatment option, could benefit patients with MDR GNR infections, especially in combination with colistin.

  17. Pyrazole derived ultra-short antimicrobial peptidomimetics with potent anti-biofilm activity.

    Science.gov (United States)

    Ahn, Mija; Gunasekaran, Pethaiah; Rajasekaran, Ganesan; Kim, Eun Young; Lee, Soo-Jae; Bang, Geul; Cho, Kun; Hyun, Jae-Kyung; Lee, Hyun-Ju; Jeon, Young Ho; Kim, Nam-Hyung; Ryu, Eun Kyoung; Shin, Song Yub; Bang, Jeong Kyu

    2017-01-05

    In this study, we report on the first chemical synthesis of ultra-short pyrazole-arginine based antimicrobial peptidomimetics derived from the newly synthesized N-alkyl/aryl pyrazole amino acids. Through the systematic tuning of hydrophobicity, charge, and peptide length, we identified the shortest peptide Py11 with the most potent antimicrobial activity. Py11 displayed greater antimicrobial activity against antibiotic-resistant bacteria, including MRSA, MDRPA, and VREF, which was approximately 2-4 times higher than that of melittin. Besides its higher selectivity (therapeutic index) toward bacterial cells than LL-37, Py11 showed highly increased proteolytic stability against trypsin digestion and maintained its antimicrobial activity in the presence of physiological salts. Interestingly, Py11 exhibited higher anti-biofilm activity against MDRPA compared to LL-37. The results from fluorescence spectroscopy and transmission electron microscopy (TEM) suggested that Py11 kills bacterial cells possibly by integrity disruption damaging the cell membrane, leading to the cytosol leakage and eventual cell lysis. Furthermore, Py11 displayed significant anti-inflammatory (endotoxin-neutralizing) activity by inhibiting LPS-induced production of nitric oxide (NO) and TNF-α. Collectively, our results suggest that Py11 may serve as a model compound for the design of antimicrobial and antisepsis agents.

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

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    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.

  19. Prediction of antibacterial activity from physicochemical properties of antimicrobial peptides.

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    Manuel N Melo

    Full Text Available 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 correlation of these with the in vivo onset of activity have only recently been proposed. In addition, such thresholds observed in model membranes occur at local peptide concentrations close to full membrane coverage. In this work we fully develop an interaction model of antimicrobial peptides with biological membranes; by exploring the consequences of the underlying partition formalism we arrive at a relationship that provides antibacterial activity prediction from two biophysical parameters: the affinity of the peptide to the membrane and the critical bound peptide to lipid ratio. A straightforward and robust method to implement this relationship, with potential application to high-throughput screening approaches, is presented and tested. In addition, disruptive thresholds in model membranes and the onset of antibacterial peptide activity are shown to occur over the same range of locally bound peptide concentrations (10 to 100 mM, which conciliates the two types of observations.

  20. 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...

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

    Science.gov (United States)

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

    2015-11-01

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

  2. Chicken antimicrobial peptides: biological functions and possible applications

    NARCIS (Netherlands)

    Dijk, Albert van

    2007-01-01

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

  3. Antimicrobial activity of human prion protein is mediated by its N-terminal region.

    Directory of Open Access Journals (Sweden)

    Mukesh Pasupuleti

    Full Text Available BACKGROUND: Cellular prion-related protein (PrP(c is a cell-surface protein that is ubiquitously expressed in the human body. The multifunctionality of PrP(c, and presence of an exposed cationic and heparin-binding N-terminus, a feature characterizing many antimicrobial peptides, made us hypothesize that PrP(c could exert antimicrobial activity. METHODOLOGY AND PRINCIPAL FINDINGS: Intact recombinant PrP exerted antibacterial and antifungal effects at normal and low pH. Studies employing recombinant PrP and N- and C-terminally truncated variants, as well as overlapping peptide 20mers, demonstrated that the antimicrobial activity is mediated by the unstructured N-terminal part of the protein. Synthetic peptides of the N-terminus of PrP killed the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the Gram-positive Bacillus subtilis and Staphylococcus aureus, as well as the fungus Candida parapsilosis. Fluorescence studies of peptide-treated bacteria, paired with analysis of peptide effects on liposomes, showed that the peptides exerted membrane-breaking effects similar to those seen after treatment with the "classical" human antimicrobial peptide LL-37. In contrast to LL-37, however, no marked helix induction was detected for the PrP-derived peptides in presence of negatively charged (bacteria-mimicking liposomes. PrP furthermore showed an inducible expression during wounding of human skin ex vivo and in vivo, as well as stimulation of keratinocytes with TGF-alpha in vitro. CONCLUSIONS: The demonstration of an antimicrobial activity of PrP, localisation of its activity to the N-terminal and heparin-binding region, combined with results showing an increased expression of PrP during wounding, indicate that PrPs could have a previously undisclosed role in host defense.

  4. S. Typhimurium strategies to resist killing by cationic antimicrobial peptides.

    Science.gov (United States)

    Matamouros, Susana; Miller, Samuel I

    2015-11-01

    S. Typhimurium is a broad host range Gram-negative pathogen that must evade killing by host innate immune systems to colonize, replicate, cause disease, and be transmitted to other hosts. A major pathogenic strategy of Salmonellae is entrance, survival, and replication within eukaryotic cell phagocytic vacuoles. These phagocytic vacuoles and gastrointestinal mucosal surfaces contain multiple cationic antimicrobial peptides (CAMPs) which control invading bacteria. S. Typhimurium possesses several key mechanisms to resist killing by CAMPs which involve sensing CAMPs and membrane damage to activate signaling cascades that result in remodeling of the bacterial envelope to reduce its overall negative charge with an increase in hydrophobicity to decrease binding and effectiveness of CAMPs. Moreover Salmonellae have additional mechanisms to resist killing by CAMPs including an outer membrane protease which targets cationic peptides at the surface, and specific efflux pumps which protect the inner membrane from damage. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.

  5. Novel antimicrobial peptides with high anticancer activity and selectivity.

    Directory of Open Access Journals (Sweden)

    Hung-Lun Chu

    Full Text Available We describe a strategy to boost anticancer activity and reduce normal cell toxicity of short antimicrobial peptides by adding positive charge amino acids and non-nature bulky amino acid β-naphthylalanine residues to their termini. Among the designed peptides, K4R2-Nal2-S1 displayed better salt resistance and less toxicity to hRBCs and human fibroblast than Nal2-S1 and K6-Nal2-S1. Fluorescence microscopic studies indicated that the FITC-labeled K4R2-Nal2-S1 preferentially binds cancer cells and causes apoptotic cell death. Moreover, a significant inhibition in human lung tumor growth was observed in the xenograft mice treated with K4R2-Nal2-S1. Our strategy provides new opportunities in the development of highly effective and selective antimicrobial and anticancer peptide-based therapeutics.

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

    Science.gov (United States)

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

    2008-08-01

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

  7. INTERNALIZATION OF ANTIMICROBIAL PEPTIDE ACIPENSIN 1 INTO HUMAN TUMOR CELLS

    Directory of Open Access Journals (Sweden)

    E. S. Umnyakova

    2016-01-01

    Full Text Available Search for new compounds providing delivery of drugs into infected or neoplastic cells, is an important direction of biomedical research. Cell-penetrating peptides are among those compounds, due to their ability to translocate through membranes of eukaryotic cells, serving as potential carriers of various therapeutic agents to the target cells. The aim of present work was to investigate the ability of acipensin 1, an antimicrobial peptide of innate immune system, for in vitro penetration into human tumor cells. Acipensin 1 is a cationic peptide that we have previously isolated from leukocytes of the Russian sturgeon, Acipenser gueldenstaedtii. Capability of acipensin 1 to enter the human erytroleukemia K-562 cells has been investigated for the first time. A biotechnological procedure for producing a recombinant acipensin 1 peptide has been developed. The obtained peptide was conjugated with a fluorescent probe BODIPY FL. By means of confocal microscopy, we have shown that the tagged acipensin 1 rapidly enters into K-562 cells and can be detected in the intracellular space within 5 min after its addition to the cell culture. Using flow cytometry technique, penetration kinetics of the labeled peptide into K-562 cells (at nontoxic micromolar concentrations has been studied. We have observed a rapid internalization of the peptide to the target cells, thus confirming the results of microscopic analysis, i.e, the labeled acipensin was detectable in K-562 cells as soon as wihin 2-3 seconds after its addition to the incubation medium. The maximum of fluorescence was reached within a period of approx. 45 seconds, with further “plateau” at the terms of >100 seconds following cell stimulation with the test compound. These data support the concept, that the antimicrobial peptides of innate immunity system possess the features of cell-penetrating peptides, and allow us to consider the studied sturgeon peptide a promising template for development of new

  8. Design and Engineering Strategies for Synthetic Antimicrobial Peptides

    Science.gov (United States)

    Tossi, Alessandro

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

  9. Antimicrobial peptides from the skins of North American frogs.

    Science.gov (United States)

    Conlon, J Michael; Kolodziejek, Jolanta; Nowotny, Norbert

    2009-08-01

    North America is home to anuran species belonging to the families Bufonidae, Eleutherodactylidae, Hylidae, Leiopelmatidae, Ranidae, and Scaphiopodidae but antimicrobial peptides have been identified only in skin secretions and/or skin extracts of frogs belonging to the Leiopelmatidae ("tailed frogs") and Ranidae ("true frogs"). Eight structurally-related cationic alpha-helical peptides with broad-spectrum antibacterial activity, termed ascaphins, have been isolated from specimens of Ascaphus truei (Leiopelmatidae) occupying a coastal range. Characterization of orthologous antimicrobial peptides from Ascaphus specimens occupying an inland range supports the proposal that this population should be regarded as a separate species A. montanus. Ascaphin-8 shows potential for development into a therapeutically valuable anti-infective agent. Peptides belonging to the brevinin-1, esculentin-1, esculentin-2, palustrin-1, palustrin-2, ranacyclin, ranatuerin-1, ranatuerin-2, and temporin families have been isolated from North American ranids. It is proposed that "ranalexins" represent brevinin-1 peptides that have undergone a four amino acid residue internal deletion. Current taxonomic recommendations divide North American frogs from the family Ranidae into two genera: Lithobates and Rana. Cladistic analysis based upon the amino acid sequences of the brevinin-1 peptides provides strong support for this assignment.

  10. The role of antimicrobial peptides in animal defenses

    Science.gov (United States)

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

    2000-08-01

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

  11. Mechanisms of Antimicrobial Peptide Resistance in Gram-Negative Bacteria

    Directory of Open Access Journals (Sweden)

    Victor I. Band

    2014-12-01

    Full Text Available Cationic antimicrobial peptides (CAMPs are important innate immune defenses that inhibit colonization by pathogens and contribute to clearance of infections. Gram-negative bacterial pathogens are a major target, yet many of them have evolved mechanisms to resist these antimicrobials. These resistance mechanisms can be critical contributors to bacterial virulence and are often crucial for survival within the host. Here, we summarize methods used by Gram-negative bacteria to resist CAMPs. Understanding these mechanisms may lead to new therapeutic strategies against pathogens with extensive CAMP resistance.

  12. Post-translational Modifications of Natural Antimicrobial Peptides and Strategies for Peptide Engineering.

    Science.gov (United States)

    Wang, Guangshun

    2012-02-01

    Natural antimicrobial peptides (AMPs) are gene-coded defense molecules discovered in all the three life domains: Eubacteria, Archaea, and Eukarya. The latter covers protists, fungi, plants, and animals. It is now recognized that amino acid composition, peptide sequence, and post-translational modifications determine to a large extent the structure and function of AMPs. This article systematically describes post-translational modifications of natural AMPs annotated in the antimicrobial peptide database (http://aps.unmc.edu/AP). Currently, 1147 out of 1755 AMPs in the database are modified and classified into more than 17 types. Through chemical modifications, the peptides fold into a variety of structural scaffolds that target bacterial surfaces or molecules within cells. Chemical modifications also confer desired functions to a particular peptide. Meanwhile, these modifications modulate other peptide properties such as stability. Elucidation of the relationship between AMP property and chemical modification inspires peptide engineering. Depending on the objective of our design, peptides may be modified in various ways so that the desired features can be enhanced whereas unwanted properties can be minimized. Therefore, peptide design plays an essential role in developing natural AMPs into a new generation of therapeutic molecules.

  13. Small cationic antimicrobial peptides delocalize peripheral membrane proteins.

    Science.gov (United States)

    Wenzel, Michaela; Chiriac, Alina Iulia; Otto, Andreas; Zweytick, Dagmar; May, Caroline; Schumacher, Catherine; Gust, Ronald; Albada, H Bauke; Penkova, Maya; Krämer, Ute; Erdmann, Ralf; Metzler-Nolte, Nils; Straus, Suzana K; Bremer, Erhard; Becher, Dörte; Brötz-Oesterhelt, Heike; Sahl, Hans-Georg; Bandow, Julia Elisabeth

    2014-04-08

    Short antimicrobial peptides rich in arginine (R) and tryptophan (W) interact with membranes. To learn how this interaction leads to bacterial death, we characterized the effects of the minimal pharmacophore RWRWRW-NH2. A ruthenium-substituted derivative of this peptide localized to the membrane in vivo, and the peptide also integrated readily into mixed phospholipid bilayers that resemble Gram-positive membranes. Proteome and Western blot analyses showed that integration of the peptide caused delocalization of peripheral membrane proteins essential for respiration and cell-wall biosynthesis, limiting cellular energy and undermining cell-wall integrity. This delocalization phenomenon also was observed with the cyclic peptide gramicidin S, indicating the generality of the mechanism. Exogenous glutamate increases tolerance to the peptide, indicating that osmotic destabilization also contributes to antibacterial efficacy. Bacillus subtilis responds to peptide stress by releasing osmoprotective amino acids, in part via mechanosensitive channels. This response is triggered by membrane-targeting bacteriolytic peptides of different structural classes as well as by hypoosmotic conditions.

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

    Science.gov (United States)

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

    2009-01-01

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

  15. Peptides from the scorpion Vaejovis punctatus with broad antimicrobial activity.

    Science.gov (United States)

    Ramírez-Carreto, Santos; Jiménez-Vargas, Juana María; Rivas-Santiago, Bruno; Corzo, Gerardo; Possani, Lourival D; Becerril, Baltazar; Ortiz, Ernesto

    2015-11-01

    The antimicrobial potential of two new non-disulfide bound peptides, named VpAmp1.0 (LPFFLLSLIPSAISAIKKI, amidated) and VpAmp2.0 (FWGFLGKLAMKAVPSLIGGNKSSSK) is here reported. These are 19- and 25-aminoacid-long peptides with +2 and +4 net charges, respectively. Their sequences correspond to the predicted mature regions from longer precursors, putatively encoded by cDNAs derived from the venom glands of the Mexican scorpion Vaejovis punctatus. Both peptides were chemically synthesized and assayed against a variety of microorganisms, including pathogenic strains from clinical isolates and strains resistant to conventional antibiotics. Two shorter variants, named VpAmp1.1 (FFLLSLIPSAISAIKKI, amidated) and VpAmp2.1 (FWGFLGKLAMKAVPSLIGGNKK), were also synthesized and tested. The antimicrobial assays revealed that the four synthetic peptides effectively inhibit the growth of both Gram-positive (Staphylococcus aureus and Streptococcus agalactiaea) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, with MICs in the range of 2.5-24.0 μM; yeasts (Candida albicans and Candida glabrata) with MICs of 3.1-50.0 μM; and two clinically isolated strains of Mycobacterium tuberculosis-including a multi-drug resistant one- with MICs in the range of 4.8-30.5 μM. A comparison between the activities of the original peptides and their derivatives gives insight into the structural/functional role of their distinctive residues.

  16. Antimicrobial Lactoferrin Peptides: The Hidden Players in the Protective Function of a Multifunctional Protein

    Science.gov (United States)

    Sinha, Mau; Kaushik, Sanket; Kaur, Punit; Singh, Tej P.

    2013-01-01

    Lactoferrin is a multifunctional, iron-binding glycoprotein which displays a wide array of modes of action to execute its primary antimicrobial function. It contains various antimicrobial peptides which are released upon its hydrolysis by proteases. These peptides display a similarity with the antimicrobial cationic peptides found in nature. In the current scenario of increasing resistance to antibiotics, there is a need for the discovery of novel antimicrobial drugs. In this context, the structural and functional perspectives on some of the antimicrobial peptides found in N-lobe of lactoferrin have been reviewed. This paper provides the comparison of lactoferrin peptides with other antimicrobial peptides found in nature as well as interspecies comparison of the structural properties of these peptides within the native lactoferrin. PMID:23554820

  17. Antimicrobial peptides and proteins of the horse - insights into a well-armed organism

    Directory of Open Access Journals (Sweden)

    Bruhn Oliver

    2011-09-01

    Full Text Available Abstract Antimicrobial peptides play a pivotal role as key effectors of the innate immune system in plants and animals and act as endogenous antibiotics. The molecules exhibit an antimicrobial activity against bacteria, viruses, and eukaryotic pathogens with different specificities and potencies depending on the structure and amino-acid composition of the peptides. Several antimicrobial peptides were comprehensively investigated in the last three decades and some molecules with remarkable antimicrobial properties have reached the third phase of clinical studies. Next to the peptides themselves, numerous organisms were examined and analyzed regarding their repertoire of antimicrobial peptides revealing a huge number of candidates with potencies and properties for future medical applications. One of these organisms is the horse, which possesses numerous peptides that are interesting candidates for therapeutical applications in veterinary medicine. Here we summarize investigations and knowledge on equine antimicrobial peptides, point to interesting candidates, and discuss prospects for therapeutical applications.

  18. Identification of multiple antimicrobial peptides from the skin of fine-spined frog, Hylarana spinulosa (Ranidae).

    Science.gov (United States)

    Yang, Xiaolong; Hu, Yuhong; Xu, Shiqi; Hu, Yonghong; Meng, Hao; Guo, Chao; Liu, Yuliang; Liu, Jingze; Yu, Zhijun; Wang, Hui

    2013-12-01

    In this study, peptidomics and genomics analyses were used to study antimicrobial peptides from the skin of Hylarana spinulosa. Twenty-nine different antimicrobial peptide precursors were characterized from the skin of H. spinulosa, which produce 23 mature antimicrobial peptides belonging to 12 different families. To confirm the actual presence and characteristics of these antimicrobial peptides in the skin tissue extractions from H. spinulosa, we used two distinct methods, one was peptide purification method that combined gel filtration chromatography and reversed-phase high performance liquid chromatography (RP-HPLC), and the other was peptidomics approach based on liquid chromatography in conjunction with tandem mass spectrometry (LC-MS/MS). In the peptidomics approach, incomplete tryptic digestion and gas-phase fractionation (GPF) analysis were used to increase peptidome coverage and reproducibility of peptide ion selection. Multiple species of microorganisms were chosen to test and analyze the antimicrobial activities and spectrum of these antimicrobial peptides.

  19. Antimicrobial Lactoferrin Peptides: The Hidden Players in the Protective Function of a Multifunctional Protein

    Directory of Open Access Journals (Sweden)

    Mau Sinha

    2013-01-01

    Full Text Available Lactoferrin is a multifunctional, iron-binding glycoprotein which displays a wide array of modes of action to execute its primary antimicrobial function. It contains various antimicrobial peptides which are released upon its hydrolysis by proteases. These peptides display a similarity with the antimicrobial cationic peptides found in nature. In the current scenario of increasing resistance to antibiotics, there is a need for the discovery of novel antimicrobial drugs. In this context, the structural and functional perspectives on some of the antimicrobial peptides found in N-lobe of lactoferrin have been reviewed. This paper provides the comparison of lactoferrin peptides with other antimicrobial peptides found in nature as well as interspecies comparison of the structural properties of these peptides within the native lactoferrin.

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

    Science.gov (United States)

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

    2009-07-01

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

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

    OpenAIRE

    2010-01-01

    Previously melittin, the α-helical basic honey bee venom peptide, was shown to inhibit F1-ATPase by binding at the β-subunit DELSEED motif of F1Fo ATP synthase. Herein, we present the inhibitory effects of the basic α-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 F1 and membrane bound F1Fo E. coli ATP synthase. We found that the extent of inhibition by amphib...

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

    Science.gov (United States)

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

    2011-03-01

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

  3. Salivary Antimicrobial Peptides in Early Detection of Periodontitis.

    Science.gov (United States)

    Güncü, Güliz N; Yilmaz, Dogukan; Könönen, Eija; Gürsoy, Ulvi K

    2015-01-01

    In the pathogenesis of periodontitis, an infection-induced inflammatory disease of the tooth-supporting tissues, there is a complex interaction between the subgingival microbiota and host tissues. A periodontal diagnostic tool for detecting the initiation and progression of the disease, monitoring the response to therapy, or measuring the degree of susceptibility to future disease progression has been of interest for a long time. The value of various enzymes, proteins, and immunoglobulins, which are abundant constituents of saliva, as potential biomarkers has been recognized and extensively investigated for periodontal diseases. Gingival defensins and cathelicidins are small cationic antimicrobial peptides that play an important role in innate immune response. However, their applicability as salivary biomarkers is still under debate. The present review focuses on proteomic biomarkers and antimicrobial peptides, in particular, to be used at early phases of periodontitis.

  4. Salivary Antimicrobial Peptides in Early Detection of Periodontitis

    Directory of Open Access Journals (Sweden)

    Guliz N. eGuncu

    2015-12-01

    Full Text Available In the pathogenesis of periodontitis, an infection-induced inflammatory disease of the tooth-supporting tissues, there is a complex interaction between the subgingival microbiota and host tissues. A periodontal diagnostic tool for detecting the initiation and progression of the disease, monitoring the response to therapy, or measuring the degree of susceptibility to future disease progression has been of interest for a long time. The value of various enzymes, proteins, and immunoglobulins, which are abundant constituents of saliva, as potential biomarkers has been recognized and extensively investigated for periodontal diseases. Gingival defensins and cathelicidins are small cationic antimicrobial peptides that play an important role in innate immune response. However, their applicability as salivary biomarkers is still under debate. The present review focuses on proteomic biomarkers and antimicrobial peptides, in particular, to be used at early phases of periodontitis.

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

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    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.

  6. 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.

  7. 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'.

  8. 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.

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

    Science.gov (United States)

    Malanovic, Nermina; Lohner, Karl

    2016-05-01

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

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

    Science.gov (United States)

    Pasupuleti, Mukesh; Schmidtchen, Artur; Malmsten, Martin

    2012-06-01

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

  11. 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......-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...

  12. 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.

  13. 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.

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

    Science.gov (United States)

    Katzenback, Barbara A

    2015-09-25

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

  15. 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.

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

    Science.gov (United States)

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

    2005-05-01

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

  17. Database-Guided Discovery of Potent Peptides to Combat HIV-1 or Superbugs

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2013-05-01

    Full Text Available Antimicrobial peptides (AMPs, small host defense proteins, are indispensable for the protection of multicellular organisms such as plants and animals from infection. The number of AMPs discovered per year increased steadily since the 1980s. Over 2,000 natural AMPs from bacteria, protozoa, fungi, plants, and animals have been registered into the antimicrobial peptide database (APD. The majority of these AMPs (>86% possess 11–50 amino acids with a net charge from 0 to +7 and hydrophobic percentages between 31–70%. This article summarizes peptide discovery on the basis of the APD. The major methods are the linguistic model, database screening, de novo design, and template-based design. Using these methods, we identified various potent peptides against human immunodeficiency virus type 1 (HIV-1 or methicillin-resistant Staphylococcus aureus (MRSA. While the stepwise designed anti-HIV peptide is disulfide-linked and rich in arginines, the ab initio designed anti-MRSA peptide is linear and rich in leucines. Thus, there are different requirements for antiviral and antibacterial peptides, which could kill pathogens via different molecular targets. The biased amino acid composition in the database-designed peptides, or natural peptides such as θ-defensins, requires the use of the improved two-dimensional NMR method for structural determination to avoid the publication of misleading structure and dynamics. In the case of human cathelicidin LL-37, structural determination requires 3D NMR techniques. The high-quality structure of LL-37 provides a solid basis for understanding its interactions with membranes of bacteria and other pathogens. In conclusion, the APD database is a comprehensive platform for storing, classifying, searching, predicting, and designing potent peptides against pathogenic bacteria, viruses, fungi, parasites, and cancer cells.

  18. Searching for Synthetic Antimicrobial Peptides: An Experiment for Organic Chemistry Students

    Science.gov (United States)

    Vasquez, Thomas E., Jr.; Saldan~a, Cristina; Muzikar, Katy A.; Mashek, Debra; Liu, Jane M.

    2016-01-01

    This laboratory experiment provides undergraduate students enrolled in organic chemistry the opportunity to design and synthesize their own peptide, which is then tested for antimicrobial activity. After reading a primary scientific paper on antimicrobial peptides, students design and synthesize their own hexapeptide that they hypothesize will…

  19. 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.

  20. Cationic antimicrobial peptides disrupt the Streptococcus pyogenes ExPortal.

    Science.gov (United States)

    Vega, Luis Alberto; Caparon, Michael G

    2012-09-01

    Although they possess a well-characterized ability to porate the bacterial membrane, emerging research suggests that cationic antimicrobial peptides (CAPs) can influence pathogen behaviour at levels that are sublethal. In this study, we investigated the interaction of polymyxin B and human neutrophil peptide (HNP-1) with the human pathogen Streptococcus pyogenes. At sublethal concentrations, these CAPs preferentially targeted the ExPortal, a unique microdomain of the S. pyogenes membrane, specialized for protein secretion and processing. A consequence of this interaction was the disruption of ExPortal organization and a redistribution of ExPortal components into the peripheral membrane. Redistribution was associated with inhibition of secretion of certain toxins, including the SpeB cysteine protease and the streptolysin O (SLO) cytolysin, but not SIC, a protein that protects S. pyogenes from CAPs. These data suggest a novel function for CAPs in targeting the ExPortal and interfering with secretion of factors required for infection and survival. This mechanism may prove valuable for the design of new types of antimicrobial agents to combat the emergence of antibiotic-resistant pathogens.

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

    Science.gov (United States)

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

    2011-10-01

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

  2. 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.

  3. Defensins and cystein rich peptides: two types of antimicrobial peptides in marine molluscs

    Directory of Open Access Journals (Sweden)

    G Arenas Díaz

    2010-06-01

    Full Text Available This review focuses on defensins and cystein rich peptides, which are the most abundant natural antimicrobial peptides (AMPs described in molluscs. These are compact peptides, 3-5 kDa in molecular mass, cationic and amphipatic; the presence of at least six cysteine residues forming three or four disulfide bridges is their prime structural characteristic. A 3-D structural characterization of these molecules has been included in recent investigations, using currently-available techniques. AMPs have been purified from hemocytes, epithelial tissue and plasma as well as cloned and chemically synthesized. Their antibacterial activity against Gram-positive and Gram-negative bacteria and fungi has been shown; only a synthetic mytilin fragment has displayed activity against viruses.

  4. Discovery of novel antimicrobial peptides with unusual cysteine motifs in dandelion Taraxacum officinale Wigg. flowers.

    Science.gov (United States)

    Astafieva, A A; Rogozhin, E A; Odintsova, T I; Khadeeva, N V; Grishin, E V; Egorov, Ts A

    2012-08-01

    Three novel antimicrobial peptides designated ToAMP1, ToAMP2 and ToAMP3 were purified from Taraxacum officinale flowers. Their amino acid sequences were determined. The peptides are cationic and cysteine-rich and consist of 38, 44 and 42 amino acid residues for ToAMP1, ToAMP2 and ToAMP3, respectively. Importantly, according to cysteine motifs, the peptides are representatives of two novel previously unknown families of plant antimicrobial peptides. ToAMP1 and ToAMP2 share high sequence identity and belong to 6-Cys-containing antimicrobial peptides, while ToAMP3 is a member of a distinct 8-Cys family. The peptides were shown to display high antimicrobial activity both against fungal and bacterial pathogens, and therefore represent new promising molecules for biotechnological and medicinal applications.

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

    Science.gov (United States)

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

    2013-04-11

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

  6. Characterization of antimicrobial peptide activity by electrochemical impedance spectroscopy

    Science.gov (United States)

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

    2008-01-01

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

  7. Host Antimicrobial Peptides in Bacterial Homeostasis and Pathogenesis of Disease

    Directory of Open Access Journals (Sweden)

    Derek R. Heimlich

    2014-11-01

    Full Text Available Innate immune responses function as a first line of host defense against the development of bacterial infection, and in some cases to preserve the sterility of privileged sites in the human host. Bacteria that enter these sites must counter host responses for colonization. From the host’s perspective, the innate immune system works expeditiously to minimize the bacterial threat before colonization and subsequent dysbiosis. The multifactorial nature of disease further challenges predictions of how each independent variable influences bacterial pathogenesis. From bacterial colonization to infection and through disease, the microenvironments of the host are in constant flux as bacterial and host factors contribute to changes at the host-pathogen interface, with the host attempting to eradicate bacteria and the bacteria fighting to maintain residency. A key component of this innate host response towards bacterial infection is the production of antimicrobial peptides (AMPs. As an early component of the host response, AMPs modulate bacterial load and prevent establishment of infection. Under quiescent conditions, some AMPs are constitutively expressed by the epithelium. Bacterial infection can subsequently induce production of other AMPs in an effort to maintain sterility, or to restrict colonization. As demonstrated in various studies, the absence of a single AMP can influence pathogenesis, highlighting the importance of AMP concentration in maintaining homeostasis. Yet, AMPs can increase bacterial virulence through the co-opting of the peptides or alteration of bacterial virulence gene expression. Further, bacterial factors used to subvert AMPs can modify host microenvironments and alter colonization of the residential flora that principally maintain homeostasis. Thus, the dynamic interplay between host defense peptides and bacterial factors produced to quell peptide activity play a critical role in the progression and outcome of disease.

  8. Arginine and Tryptophan rich antimicrobial peptides (AMPs) : modifications, application and mode of action

    OpenAIRE

    Penkova, Maya

    2010-01-01

    Da multiresistente Bakterienstämme ein häufiges Problem darstellen, besteht Bedarf an neuen Verbindungen, die keine Resistenzen hervorrufen. Eine solche Verbindungsklasse stellen die kationischen antimikrobiellen Peptide dar (cationic antimicrobial peptides, AMPs). Mithilfe von Festphasenpeptidsynthese wurden Peptide und deren Metallocenanaloga (Ferrocen- und Ruthenocenbiokonjugate) hergestellt und auf ihre biologische Aktivität untersucht. Alle hergestellten Verbindungen zeigten ...

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

    Directory of Open Access Journals (Sweden)

    Attila Gergely Végh

    2011-01-01

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

  10. In vivo expression of antimicrobial peptides in atopic dermatitis

    DEFF Research Database (Denmark)

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

    2016-01-01

    The aim of this review is to present findings on expression of antimicrobial peptides (AMPs) in atopic dermatitis (AD) skin, focusing only on in vivo studies, and to discuss differences in results obtained using various skin sampling techniques and different methodology for analysis of AMPs....... The review also includes a discussion of the effect of frequently used treatments on AMP expression. Many studies have shown a reduced level of AMPs in lesional AD skin when compared to psoriatic skin, explaining the high frequency of AD-related infections. Interestingly, however, non-lesional AD skin has...... shown the same upregulation of AMPs after barrier disruption as non-lesional psoriatic skin. Various methods have been used to analyse AMP expression in the skin, and when comparing these methods, differences are revealed in AMP expression depending on the method used for sampling and analysis...

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

    Directory of Open Access Journals (Sweden)

    Huang Jin-Jiang

    2012-01-01

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

  12. Fungicidal mechanisms of the antimicrobial peptide Bac8c.

    Science.gov (United States)

    Lee, Wonyoung; Lee, Dong Gun

    2015-02-01

    Bac8c (RIWVIWRR-NH2) is an analogue peptide derived through complete substitution analysis of the linear bovine host defense peptide variant Bac2A. In the present study, the antifungal mechanism of Bac8c against pathogenic fungi was investigated, with a particular focus on the effects of Bac8c on the cytoplasmic membrane. We used bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)] staining and 3,3'-dipropylthiacarbocyanine iodide [DiSC3(5)] assays to show that Bac8c induced disturbances in the membrane potential of Candida albicans. An increase in membrane permeability and suppression of cell wall regeneration were also observed in Bac8c-treated C. albicans. We studied the effects of Bac8c treatment on model membranes to elucidate its antifungal mechanism. Using calcein and FITC-labeled dextran leakage assays from Bac8c-treated large unilamellar vesicles (LUVs) and giant unilamellar vesicles (GUVs), we found that Bac8c has a pore-forming action on fungal membranes, with an estimated pore radius of between 2.3 and 3.3 nm. A membrane-targeted mechanism of action was also supported by the observation of potassium release from the cytosol of Bac8c-treated C. albicans. These results indicate that Bac8c is considered as a potential candidate to develop a novel antimicrobial agent because of its low-cost production characteristics and high antimicrobial activity via its ability to induce membrane perturbations in fungi.

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

    Science.gov (United States)

    Dziuba, Bartłomiej; Dziuba, Marta

    2014-01-01

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

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

    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.

  15. A maritime pine antimicrobial peptide involved in ammonium nutrition.

    Science.gov (United States)

    Canales, Javier; Avila, Concepción; Cánovas, Francisco M

    2011-09-01

    A large family of small cysteine-rich antimicrobial peptides (AMPs) is involved in the innate defence of plants against pathogens. Recently, it has been shown that AMPs may also play important roles in plant growth and development. In previous work, we have identified a gene of the AMP β-barrelin family that was differentially regulated in the roots of maritime pine (Pinus pinaster Ait.) in response to changes in ammonium nutrition. Here, we present the molecular characterization of two AMP genes, PpAMP1 and PpAMP2, showing different molecular structure and physicochemical properties. PpAMP1 and PpAMP2 displayed different expression patterns in maritime pine seedlings and adult trees. Furthermore, our expression analyses indicate that PpAMP1 is the major form of AMP in the tree, and its relative abundance is regulated by ammonium availability. In contrast, PpAMP2 is expressed at much lower levels and it is not regulated by ammonium. To gain new insights into the function of PpAMP1, we over-expressed the recombinant protein in Escherichia coli and demonstrated that PpAMP1 strongly inhibited yeast growth, indicating that it exhibits antimicrobial activity. We have also found that PpAMP1 alters ammonium uptake, suggesting that it is involved in the regulation of ammonium ion flux into pine roots.

  16. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Rafi eRashid

    2016-06-01

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

  17. Intestinal antimicrobial peptides during homeostasis, infection and disease

    Directory of Open Access Journals (Sweden)

    Luciana R Muniz

    2012-10-01

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

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  19. Peptidomics and genomics analysis of novel antimicrobial peptides from the frog, Rana nigrovittata.

    Science.gov (United States)

    Ma, Yufang; Liu, Cunbao; Liu, Xiuhong; Wu, Jing; Yang, Hailong; Wang, Yipeng; Li, Jianxu; Yu, Haining; Lai, Ren

    2010-01-01

    Much attention has been paid on amphibian peptides for their wide-ranging pharmacological properties, clinical potential, and gene-encoded origin. More than 300 antimicrobial peptides (AMPs) from amphibians have been studied. Peptidomics and genomics analysis combined with functional test including microorganism killing, histamine-releasing, and mast cell degranulation was used to investigate antimicrobial peptide diversity. Thirty-four novel AMPs from skin secretions of Rana nigrovittata were identified in current work, and they belong to 9 families, including 6 novel families. Other three families are classified into rugosin, gaegurin, and temporin family of amphibian AMP, respectively. These AMPs share highly conserved preproregions including signal peptides and spacer acidic peptides, while greatly diversified on mature peptides structures. In this work, peptidomics combined with genomics analysis was confirmed to be an effective way to identify amphibian AMPs, especially novel families. Some AMPs reported here will provide leading molecules for designing novel antimicrobial agents.

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

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    Sid Ahmed Labed

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Science.gov (United States)

    Kruse, Thomas; Kristensen, Hans-Henrik

    2008-12-01

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

  3. Antimicrobial Peptides: Insights into Membrane Permeabilization, Lipopolysaccharide Fragmentation and Application in Plant Disease Control

    OpenAIRE

    Datta, A.; Ghosh, A; Airoldi, C; Sperandeo, P; Mroue, K; Jimenez-Barbero, J; Kundu, P.; Ramamoorthy, A; Bhunia, A

    2015-01-01

    The recent increase in multidrug resistance against bacterial infections has become a major concern to human health and global food security. Synthetic antimicrobial peptides (AMPs) have recently received substantial attention as potential alternatives to conventional antibiotics because of their potent broad-spectrum antimicrobial activity. These peptides have also been implicated in plant disease control for replacing conventional treatment methods that are polluting and hazardous to the en...

  4. Antimicrobial activity of histidine-rich peptides is dependent on acidic conditions.

    OpenAIRE

    Kacprzyk, Lukasz; Rydengård, Victoria; Mörgelin, Matthias; Davoudi, Mina; Pasupuleti, Mukesh; Malmsten, Martin; Schmidtchen, Artur

    2007-01-01

    Synthetic peptides composed of multiples of the consensus heparin-binding Cardin and Weintraub sequences AKKARA and ARKKAAKA are antimicrobial. Replacement of lysine and arginine by histidine in these peptides completely abrogates their antimicrobial and heparin-binding activities at neutral pH. However, the antibacterial activity against Gram-negative (Escherichia coli, Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) as well as the fungus Cand...

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

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    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.

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

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    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.

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

    Science.gov (United States)

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

    2015-12-01

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

  8. LEAP-1, a novel highly disulfide-bonded human peptide, exhibits antimicrobial activity.

    Science.gov (United States)

    Krause, A; Neitz, S; Mägert, H J; Schulz, A; Forssmann, W G; Schulz-Knappe, P; Adermann, K

    2000-09-01

    We report the isolation and characterization of a novel human peptide with antimicrobial activity, termed LEAP-1 (liver-expressed antimicrobial peptide). Using a mass spectrometric assay detecting cysteine-rich peptides, a 25-residue peptide containing four disulfide bonds was identified in human blood ultrafiltrate. LEAP-1 expression was predominantly detected in the liver, and, to a much lower extent, in the heart. In radial diffusion assays, Gram-positive Bacillus megaterium, Bacillus subtilis, Micrococcus luteus, Staphylococcus carnosus, and Gram-negative Neisseria cinerea as well as the yeast Saccharomyces cerevisiae dose-dependently exhibited sensitivity upon treatment with synthetic LEAP-1. The discovery of LEAP-1 extends the known families of mammalian peptides with antimicrobial activity by its novel disulfide motif and distinct expression pattern.

  9. PFR peptide, one of the antimicrobial peptides identified from the derivatives of lactoferrin, induces necrosis in leukemia cells.

    Science.gov (United States)

    Lu, Yan; Zhang, Teng-Fei; Shi, Yue; Zhou, Han-Wei; Chen, Qi; Wei, Bu-Yun; Wang, Xi; Yang, Tian-Xin; Chinn, Y Eugene; Kang, Jian; Fu, Cai-Yun

    2016-02-10

    LF11-322 (PFWRIRIRR-NH2) (PFR peptide), a nine amino acid-residue peptide fragment derived from human lactoferricin, possesses potent cytotoxicity against bacteria. We report here the discovery and characterization of its antitumor activity in leukemia cells. PFR peptide inhibited the proliferation of MEL and HL-60 leukemia cells by inducing cell death in the absence of the classical features of apoptosis, including chromatin condensation, Annexin V staining, Caspase activation and increase of abundance of pro-apoptotic proteins. Instead, necrotic cell death as evidenced by increasing intracellular PI staining and LDH release, inducing membrane disruption and up-regulating intracellular calcium level, was observed following PFR peptide treatment. In addition to necrotic cell death, PFR peptide also induced G0/G1 cell cycle arrest. Moreover, PFR peptide exhibited favorable antitumor activity and tolerability in vivo. These findings thus provide a new clue of antimicrobial peptides as a potential novel therapy for leukemia.

  10. 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.

  11. Regulation of Antimicrobial Peptides in Aedes aegypti Aag2 Cells.

    Science.gov (United States)

    Zhang, Rudian; Zhu, Yibin; Pang, Xiaojing; Xiao, Xiaoping; Zhang, Renli; Cheng, Gong

    2017-01-01

    Antimicrobial peptides (AMPs) are an important group of immune effectors that play a role in combating microbial infections in invertebrates. Most of the current information on the regulation of insect AMPs in microbial infection have been gained from Drosophila, and their regulation in other insects are still not completely understood. Here, we generated an AMP induction profile in response to infections with some Gram-negative, -positive bacteria, and fungi in Aedes aegypti embryonic Aag2 cells. Most of the AMP inductions caused by the gram-negative bacteria was controlled by the Immune deficiency (Imd) pathway; nonetheless, Gambicin, an AMP gene discovered only in mosquitoes, was combinatorially regulated by the Imd, Toll and JAK-STAT pathways in the Aag2 cells. Gambicin promoter analyses including specific sequence motif deletions implicated these three pathways in Gambicin activity, as shown by a luciferase assay. Moreover, the recognition between Rel1 (refer to Dif/Dorsal in Drosophila) and STAT and their regulatory sites at the Gambicin promoter site was validated by a super-shift electrophoretic mobility shift assay (EMSA). Our study provides information that increases our understanding of the regulation of AMPs in response to microbial infections in mosquitoes. And it is a new finding that the A. aegypti AMPs are mainly regulated Imd pathway only, which is quite different from the previous understanding obtained from Drosophila.

  12. The Antimicrobial Peptide Lysozyme Is Induced after Multiple Trauma

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    Tim Klüter

    2014-01-01

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

  13. Regulation of Antimicrobial Peptides in Aedes aegypti Aag2 Cells

    Science.gov (United States)

    Zhang, Rudian; Zhu, Yibin; Pang, Xiaojing; Xiao, Xiaoping; Zhang, Renli; Cheng, Gong

    2017-01-01

    Antimicrobial peptides (AMPs) are an important group of immune effectors that play a role in combating microbial infections in invertebrates. Most of the current information on the regulation of insect AMPs in microbial infection have been gained from Drosophila, and their regulation in other insects are still not completely understood. Here, we generated an AMP induction profile in response to infections with some Gram-negative, -positive bacteria, and fungi in Aedes aegypti embryonic Aag2 cells. Most of the AMP inductions caused by the gram-negative bacteria was controlled by the Immune deficiency (Imd) pathway; nonetheless, Gambicin, an AMP gene discovered only in mosquitoes, was combinatorially regulated by the Imd, Toll and JAK-STAT pathways in the Aag2 cells. Gambicin promoter analyses including specific sequence motif deletions implicated these three pathways in Gambicin activity, as shown by a luciferase assay. Moreover, the recognition between Rel1 (refer to Dif/Dorsal in Drosophila) and STAT and their regulatory sites at the Gambicin promoter site was validated by a super-shift electrophoretic mobility shift assay (EMSA). Our study provides information that increases our understanding of the regulation of AMPs in response to microbial infections in mosquitoes. And it is a new finding that the A. aegypti AMPs are mainly regulated Imd pathway only, which is quite different from the previous understanding obtained from Drosophila. PMID:28217557

  14. 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.

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

    Science.gov (United States)

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

    2009-01-01

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

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

    Science.gov (United States)

    Gruenheid, Samantha; Le Moual, Hervé

    2012-05-01

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

  17. Biotic stress resistance in agriculture through antimicrobial peptides.

    Science.gov (United States)

    Sarika; Iquebal, M A; Rai, Anil

    2012-08-01

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

  18. A consistent nomenclature of antimicrobial peptides isolated from frogs of the subfamily Phyllomedusinae.

    Science.gov (United States)

    Amiche, Mohamed; Ladram, Ali; Nicolas, Pierre

    2008-11-01

    A growing number of cationic antimicrobial peptides have been isolated from the skin of hylid frogs belonging to the Phyllomedusinae subfamily. The amino acid sequences of these peptides are currently located in several databases under identifiers with no consistent system of nomenclature to describe them. In order to provide a workable terminology for antimicrobial peptides from Phyllomedusid frogs, we have made a systematic effort to collect, analyze, and classify all the Phyllomedusid peptide sequences available in databases. We propose that frogs belonging to the Phyllomedusinae subfamily should be described by the species names set out in Amphibian Species of the World: http://research.amnh.org/herpetology/amphibia/index.php, American Museum of Natural History, New York, USA. Multiple alignments analysis of at least 80 antimicrobial peptides isolated from 12 Phyllomedusinae species were distributed in seven distinct peptide families including dermaseptin, phylloseptin, plasticin, dermatoxin, phylloxin, hyposin and orphan peptides, and will be considered as the name of the headgroup of each family. The parent peptide's name should be followed by the first upper letter of the species for orthologous peptides and publication date determines priority. For example, the abbreviation B for bicolor and H for hypochondrialis. When two species begin with the same letter, two letters in upper case should be used (the first letter followed by the second or the third letter and so on). For example, the abbreviation DI for distincta, DU for duellmani, VA for vaillanti and VN for vanzolinii. Paralogous peptides should bear letter(s) in upper case followed by numbers.

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

    Directory of Open Access Journals (Sweden)

    Eni Kusumaningtyas

    2013-06-01

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

  20. Antimicrobial peptides: the role of hydrophobicity in the alpha helical structure

    Directory of Open Access Journals (Sweden)

    Pandurangan Perumal

    2013-12-01

    Full Text Available The antimicrobial peptides (AMPs are a class of molecule obtained from plants, insects, animals, and humans. These peptides have been classified into five categories: 1. Anionic peptide, 2. Linear alpha helical cationic peptide, 3. Cationic peptide, 4. Anionic and cationic peptides with disulphide bonds, and 5. Anionic and cationic peptide fragments of larger proteins. Factors affecting AMPs are sequence, size, charge, hydrophobicity, amphipathicity, structure and conformation. Synthesis of these peptides is convenient by using solid phase peptide synthesis by using FMOC chemistry protocol. The secondary structures of three synthetic peptides were determined by circular dichroism. Also, it was compared the stability of the α-helical structure and confirmed the percentage of helix of these peptides by using circular dichroism. Some of these AMPs show therapeutic properties like antimicrobial, antiviral, contraceptive, and anticancer. The formulations of some peptides have been entered into the phase I, II, or III of clinical trials. This article to review briefly the sources, classification, factors affecting AMPs activity, synthesis, characterization, mechanism of action and therapeutic concern of AMPs and mainly focussed on percentage of α-helical structure in various medium.

  1. 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...... was combined with fluorescence correlation spectroscopy to quantify leakage from a bulk collection of lipid vesicles in aqueous solution. Quantitative correlation between the two techniques was achieved through a detailed experimental protocol. The potential of combining the two techniques was tested using...

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

    Directory of Open Access Journals (Sweden)

    Lihong Liu

    2014-06-01

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

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

    Science.gov (United States)

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

    2013-11-15

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

  4. Engineered Chimeric Peptides as Antimicrobial Surface Coating Agents toward Infection-Free Implants.

    Science.gov (United States)

    Yazici, Hilal; O'Neill, Mary B; Kacar, Turgay; Wilson, Brandon R; Oren, E Emre; Sarikaya, Mehmet; Tamerler, Candan

    2016-03-02

    Prevention of bacterial colonization and consequent biofilm formation remains a major challenge in implantable medical devices. Implant-associated infections are not only a major cause of implant failures but also their conventional treatment with antibiotics brings further complications due to the escalation in multidrug resistance to a variety of bacterial species. Owing to their unique properties, antimicrobial peptides (AMPs) have gained significant attention as effective agents to combat colonization of microorganisms. These peptides have been shown to exhibit a wide spectrum of activities with specificity to a target cell while having a low tendency for developing bacterial resistance. Engineering biomaterial surfaces that feature AMP properties, therefore, offer a promising approach to prevent implant infections. Here, we engineered a chimeric peptide with bifunctionality that both forms a robust solid-surface coating while presenting antimicrobial property. The individual domains of the chimeric peptides were evaluated for their solid-binding kinetics to titanium substrate as well as for their antimicrobial properties in solution. The antimicrobial efficacy of the chimeric peptide on the implant material was evaluated in vitro against infection by a variety of bacteria, including Streptococcus mutans, Staphylococcus. epidermidis, and Escherichia coli, which are commonly found in oral and orthopedic implant related surgeries. Our results demonstrate significant improvement in reducing bacterial colonization onto titanium surfaces below the detectable limit. Engineered chimeric peptides with freely displayed antimicrobial domains could be a potential solution for developing infection-free surfaces by engineering implant interfaces with highly reduced bacterial colonization property.

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

    Science.gov (United States)

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

    2009-07-01

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

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

    Science.gov (United States)

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

    2010-11-30

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

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

    Science.gov (United States)

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

    2014-10-01

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

  8. 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.

  9. 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.

  10. 抗菌肽活性及天然抗菌肽的改造%Activities of antimicrobial peptides and the reconstruction of the natural antimicrobial peptides

    Institute of Scientific and Technical Information of China (English)

    张海波; 金莉莉; 王秋雨

    2011-01-01

    抗菌肽具有抗菌谱广、热稳定性强、分子量小及免疫原性小等特点,其杀菌机制独特,病原菌不易产生耐药性,有望开发成新一代肽类抗生素.本文主要综述了影响抗菌肽生物活性的生化性质,即螺旋度、疏水性、两亲性、正电荷数等,并从结构的角度论述了其对抗菌肽抑菌活性的影响.部分抗菌肽具有空间结构不稳定、溶血活性等缺点,限制了其临床应用.因此,对天然抗菌肽的改造也成为目前抗菌肽的研究热点,本文还综述了天然抗菌肽的改造方法.%Natural antimicrobial peptides with the features of broad antibacterial spectrum, high thermal stability, small immunogenicity and molecular weight, are expected to develop into a new generation of peptide antibiotics because of their unique bactericidal mechanism and difficulty to produce drug resistance. The effects of biochemistry character, including helicity, hydrophobicity, amphipathic property and positive charge, of antimicrobial peptides on their biological activity were reviewed in this paper and the relationship between the antibacterial activities and the structure was also discussed. Some natural antimicrobial peptides have defects such as space structure instability and hemolytic activity, which limits their clinical application. Therefore, structural modification of natural peptides has become a hot topic, and some methods for the remodeling of natural antimicrobial peptides were introduced in this paper.

  11. 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.

  12. Extreme antimicrobial peptide and polymyxin B resistance in the genus Burkholderia

    Directory of Open Access Journals (Sweden)

    Slade A. Loutet

    2011-07-01

    Full Text Available Cationic antimicrobial peptides and polymyxins are a group of naturally occurring antibiotics that can also possess immunomodulatory activities. They are considered a new source of antibiotics for treating infections by bacteria that are resistant to conventional antibiotics. Members of the genus Burkholderia, which includes various human pathogens, are inherently resistant to antimicrobial peptides. The resistance is several orders of magnitude higher than that of other Gram-negative bacteria such as Escherichia coli, Salmonella enterica, or Pseudomonas aeruginosa. This review summarizes our current understanding of antimicrobial peptide and polymyxin B resistance in the genus Burkholderia. These bacteria possess major and minor resistance mechanisms that will be described in detail. Recent studies have revealed that many other emerging Gram-negative opportunistic pathogens may also be inherently resistant to antimicrobial peptides and polymyxins and we propose that Burkholderia species are a model system to investigate the molecular basis of the resistance in extremely resistant bacteria. Understanding resistance in these types of bacteria will be important if antimicrobial peptides come to be used regularly for the treatment of infections by susceptible bacteria because this may lead to increased resistance in the species that are currently susceptible and may also open up new niches for opportunistic pathogens with high inherent resistance.

  13. Functional divergence among silkworm antimicrobial peptide paralogs by the activities of recombinant proteins and the induced expression profiles.

    Directory of Open Access Journals (Sweden)

    Wanying Yang

    Full Text Available Antimicrobial peptides are small-molecule proteins that are usually encoded by multiple-gene families. They play crucial roles in the innate immune response, but reports on the functional divergence of antimicrobial peptide gene families are rare. In this study, 14 paralogs of antimicrobial peptides belonging to cecropin, moricin and gloverin families were recombinantly expressed in pET expression systems. By antimicrobial activity tests, peptides representing paralogs in the same family of cecropin and moricin families, displayed remarkable differences against 10 tested bacteria. The evolutionary rates were relatively fast in the two families, which presented obvious functional divergence among paralogs of each family. Four peptides of gloverin family had similar antimicrobial spectrum and activity against tested bacteria. The gloverin family showed similar antimicrobial function and slow evolutionary rates. By induced transcriptional activity, genes encoding active antimicrobial peptides were upregulated at obviously different levels when silkworm pupae were infected by three types of microbes. Association analysis of antimicrobial activities and induced transcriptional activities indicated that the antimicrobial activities might be positively correlated with induced transcriptional activities in the cecropin and moricin families. These results suggest that representative BmcecB6, BmcecD and Bmmor as the major effector genes have broad antimicrobial spectrum, strong antimicrobial activity and high microbe-induced expression among each family and maybe play crucial roles in eliminating microbial infection.

  14. A Mig-14-like protein (PA5003) affects antimicrobial peptide recognition in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Jochumsen, Nicholas; Liu, Yang; Molin, Søren

    2011-01-01

    are attractive candidates for novel drug development due to their activity against bacteria that are resistant to conventional antibiotics, and reports of peptide resistance are rare in the clinical setting. Paradoxically, many clinically relevant bacteria have mechanisms that can recognize and respond......The evolution of antibiotic resistance in pathogenic bacteria is a growing global health problem which is gradually making the treatment of infectious diseases less efficient. Antimicrobial peptides are small charged molecules found in organisms from the complete phylogenetic spectrum. The peptides...... modification operon arnBCADTEF–PA3559 which encodes enzymes required for LPS alterations leading to increased antimicrobial peptide tolerance. The expression of the operon is induced by the presence of CAMPs in the environment but the molecular mechanisms underlying the cellular recognition of the peptides...

  15. Two novel antimicrobial peptides from skin venoms of spadefoot toad Megophrys minor.

    Science.gov (United States)

    Yang, Hong-Ling; Shen, Zhi-Qiang; Liu, Xuan; Kong, Yi

    2016-04-01

    Amphibian skin contains rich bioactive peptides. Especially, a large amount of antimicrobial peptides have been identified from amphibian skin secretions. Antimicrobial peptides display potent cytolytic activities against a range of pathogenic bacteria and fungi and play important defense roles. No antimicrobial peptides have been reported from toads belonging to the family of Pelobatidae. In this work, two novel antimicrobial peptides (Megin 1 and Megin 2) were purified and characterized from the skin venoms of spadefoot toad Megophrys minor (Pelobatidae, Anura, Amphibia). Megin 1 had an amino acid sequence of FLKGCWTKWYSLKPKCPF-NH2, which was composed of 18 amino acid residues and contained an intra-molecular disulfide bridge and an amidated C-terminus. Megin 2 had an amino acid sequence of FFVLKFLLKWAGKVGLEHLACKFKNWC, which was composed of 27 amino acid residues and contained an intra-molecular disulfide bridge. Both Megin 1 and Megin 2 showed potential antimicrobial abilities against bacteria and fungi. The MICs of Megin 1 against Escherichia coli, Bacillus dysenteriae, Staphylococcus aureus, Bacillus subtilis, and Candida albicans were 25, 3, 6.25, 3, and 50 μg·mL(-1), respectively. The corresponding MICs for Megin 2 were 6.25, 1.5, 12.5, 1.5, and 12.5 μg·mL(-1), respectively. They also exerted strong hemolytic activity against human and rabbit red cells. The results suggested that megin peptides in the toad skin of M. minor displayed toxic effects on both eukaryotes and prokaryotes. This was the first report of antimicrobial peptides from amphibians belonging to the family of Pelobatidae.

  16. 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.

  17. 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

  18. Flagellin stimulates protective lung mucosal immunity: role of cathelicidin-related antimicrobial peptide.

    Science.gov (United States)

    Yu, Fu-shin; Cornicelli, Matthew D; Kovach, Melissa A; Newstead, Michael W; Zeng, Xianying; Kumar, Ashok; Gao, Nan; Yoon, Sang Gi; Gallo, Richard L; Standiford, Theodore J

    2010-07-15

    TLRs are required for generation of protective lung mucosal immune responses against microbial pathogens. In this study, we evaluated the effect of the TLR5 ligand flagellin on stimulation of antibacterial mucosal immunity in a lethal murine Pseudomonas aeruginosa pneumonia model. The intranasal pretreatment of mice with purified P. aeruginosa flagellin induced strong protection against intratracheal P. aeruginosa-induced lethality, which was attributable to markedly improved bacterial clearance, reduced dissemination, and decreased alveolar permeability. The protective effects of flagellin on survival required TLR5 and were observed even in the absence of neutrophils. Flagellin induced strong induction of innate genes, most notably the antimicrobial peptide cathelicidin-related antimicrobial peptide. Finally, flagellin-induced protection was partially abrogated in cathelicidin-related antimicrobial peptide-deficient mice. Our findings illustrate the profound stimulatory effect of flagellin on lung mucosal innate immunity, a response that might be exploited therapeutically to prevent the development of gram-negative bacterial infection of the respiratory tract.

  19. Differential expression of antimicrobial peptides in active and latent tuberculosis and its relationship with diabetes mellitus.

    Science.gov (United States)

    Gonzalez-Curiel, Irma; Castañeda-Delgado, Julio; Lopez-Lopez, Nallely; Araujo, Zaida; Hernandez-Pando, Rogelio; Gandara-Jasso, Benjamin; Macias-Segura, Noe; Enciso-Moreno, Antonio; Rivas-Santiago, Bruno

    2011-08-01

    Tuberculosis (TB) is one of the most important infectious diseases, causing 1.8 million deaths annually worldwide. This problem has increased because of the association with human immmunodeficiency virus and diabetes mellitus type 2, mainly in developing countries. In the past few years it has been highlighted the significance of antimicrobial peptides in the immunopathogenesis of TB ex vivo and in experimental models studies. In this study we analyzed the expression of CAMP, DEFA1, DEFB4, and DEFB103A in patients with latent TB and progressive TB with and without comorbidity with diabetes mellitus type 2. Antimicrobial peptide gene expression increased during progressive TB, which could be used as a biomarker for reactivation. By contrast, patients with diabetes mellitus type 2 have lower antimicrobial peptides gene expression, suggesting that the lack of its proper production in these patients contribute to enhance the risk for TB reactivation.

  20. The coordinated Response of the Physical and Antimicrobial Peptide Barriers of the Skin

    Science.gov (United States)

    Borkowski, Andrew W.; Gallo, Richard L.

    2011-01-01

    Antimicrobial peptides (AMPs) are an essential and multifunctional element for immune defense of the skin during infection and injury. In this issue, Ahrens et al. characterize the response of β-defensins, a class of AMPs, following acute and chronic challenges to the permeability barrier of the skin. Their findings suggest that the antimicrobial and permeability barriers of the skin are closely linked. PMID:21228809

  1. Antimicrobial Peptide Structure and Mechanism of Action: A Focus on the Role of Membrane Structure.

    Science.gov (United States)

    Lee, Tzong-Hsien; Hall, Kristopher N; Aguilar, Marie-Isabel

    2016-01-01

    Antimicrobial peptides (AMPs) are showing increasing promise as potential candidate antibacterial drugs in the face of the rapidly emerging bacterial resistance to conventional antibiotics in recent years. The target of these peptides is the microbial membrane and there are numerous models to explain their mechanism of action ranging from pore formation to general membrane disruption. The interaction between the AMP and the target membrane is critical to the specificity and activity of these peptides. However, a precise understanding of the relationship between antimicrobial peptide structure and their cytolytic function in a range of organisms is still lacking. This is a result of the complex nature of the interactions of AMPs with the cell membrane, the mechanism of which can vary considerably between different classes of antimicrobia peptides. A wide range of biophysical techniques have been used to study the influence of a number of peptide and membrane properties on the cytolytic activity of these peptides in model membrane systems. Central to characterisation of this interaction is a quantitative analysis of the binding of peptide to the membrane and the coherent dynamic changes in membrane structure. Recently, dual polarization interferometry has been used to perform an in depth analysis of antimicrobial peptide induced membrane perturbation and with new mass-structure co-fitting kinetic analysis have allowed a real-time label free analysis of binding affinity and kinetics. We review these studies which describe multi-step mechanisms which are adopted by various AMPs in nature and may advance our approach to the development of a new generation of effective antimicrobial therapeutics.

  2. 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

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

    NARCIS (Netherlands)

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

    1995-01-01

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

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

    Science.gov (United States)

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

    2016-08-10

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

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

    Directory of Open Access Journals (Sweden)

    Monica Benincasa

    2016-08-01

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

  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.

  7. Synthetic mimic of antimicrobial peptide with nonmembrane-disrupting antibacterial properties.

    Science.gov (United States)

    Gabriel, Gregory J; Madkour, Ahmad E; Dabkowski, Jeffrey M; Nelson, Christopher F; Nüsslein, Klaus; Tew, Gregory N

    2008-11-01

    Polyguanidinium oxanorbornene ( PGON) was synthesized from norbornene monomers via ring-opening metathesis polymerization. This polymer was observed to be strongly antibacterial against Gram-negative and Gram-positive bacteria as well as nonhemolytic against human red blood cells. Time-kill studies indicated that this polymer is lethal and not just bacteriostatic. In sharp contrast to previously reported SMAMPs (synthetic mimics of antimicrobial peptides), PGON did not disrupt membranes in vesicle-dye leakage assays and microscopy experiments. The unique biological properties of PGON, in same ways similar to cell-penetrating peptides, strongly encourage the examination of other novel guanidino containing macromolecules as powerful and selective antimicrobial agents.

  8. Conformational study of melectin and antapin antimicrobial peptides in model membrane environments

    Science.gov (United States)

    Kocourková, Lucie; Novotná, Pavlína; Čujová, Sabína; Čeřovský, Václav; Urbanová, Marie; Setnička, Vladimír

    2017-01-01

    Antimicrobial peptides have long been considered as promising compounds against drug-resistant pathogens. In this work, we studied the secondary structure of antimicrobial peptides melectin and antapin using electronic (ECD) and vibrational circular dichroism (VCD) spectroscopies that are sensitive to peptide secondary structures. The results from quantitative ECD spectral evaluation by Dichroweb and CDNN program and from the qualitative evaluation of the VCD spectra were compared. The antimicrobial activity of the selected peptides depends on their ability to adopt an amphipathic α-helical conformation on the surface of the bacterial membrane. Hence, solutions of different zwitterionic and negatively charged liposomes and micelles were used to mimic the eukaryotic and bacterial biological membranes. The results show a significant content of α-helical conformation in the solutions of negatively charged liposomes mimicking the bacterial membrane, thus correlating with the antimicrobial activity of the studied peptides. On the other hand in the solutions of zwitterionic liposomes used as models of the eukaryotic membranes, the fraction of α-helical conformation was lower, which corresponds with their moderate hemolytic activity.

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

    Institute of Scientific and Technical Information of China (English)

    姚佳; 周玉玲; 张贞; 王宁

    2012-01-01

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

  10. [Role of antimicrobial peptides (AMP) and pattern recognition receptors (PRR) in the intestinal mucosa homeostasis].

    Science.gov (United States)

    Lapis, Károly

    2009-11-22

    Homeostasis and integrity of bowel mucosa is assured by well controlled mechanical, biochemical and immunological mechanisms. First line of defense is presented by the antimicrobial peptides (AMP), which form a continuous layer on the bowel surface, produced by intestinal specific (Paneth) and non-specific epithelial cells. AMPs have a significant antimicrobial, antifungal and antiviral, as well as immunomodulatory effects. Next line of defense is the pattern recognition receptors (PRR), which allows identifying conservative molecular patterns of different pathogens, and starts antimicrobial and inflammatory mechanisms through gene-expression induction. We review the most recent knowledge and studies concerning these mechanisms.

  11. Antimicrobial activity of GN peptides and their mode of action

    DEFF Research Database (Denmark)

    Godballe, Troels; Mojsoska, Biljana; Nielsen, Hanne M

    2015-01-01

    Increasing prevalence of bacteria that carries resistance towards conventional antibiotics has prompted the investigation into new compounds for bacterial intervention to ensure efficient infection control in the future. One group of potential lead structures for antibiotics is antimicrobial pept...

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

    Science.gov (United States)

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

    2010-08-01

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

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    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....

  14. Enhanced Antimicrobial Activity of AamAP1-Lysine, a Novel Synthetic Peptide Analog Derived from the Scorpion Venom Peptide AamAP1

    Directory of Open Access Journals (Sweden)

    Ammar Almaaytah

    2014-04-01

    Full Text Available There is great interest in the development of antimicrobial peptides as a potentially novel class of antimicrobial agents. Several structural determinants are responsible for the antimicrobial and cytolytic activity of antimicrobial peptides. In our study, a new synthetic peptide analog, AamAP1-Lysine from the naturally occurring scorpion venom antimicrobial peptide AamAP1, was designed by modifying the parent peptide in order to increase the positive charge and optimize other physico-chemical parameters involved in antimicrobial activity. AamAP1-Lysine displayed potent antibacterial activity against Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration was in the range of 5 to 15 µM with a 10 fold increase in potency over the parent peptide. The hemolytic and antiproliferative activity of AamAP1-Lysine against eukaryotic mammalian cells was minimal at the concentration range needed to inhibit bacterial growth. The antibacterial mechanism analysis indicated that AamAP1-Lysine is probably inducing bacterial cell death through membrane damage and permeabilization determined by the release of β-galactosidase enzyme from peptide treated E. coli cells. DNA binding studies revealed that AamAP1-Lysine caused complete retardation of DNA migration and could display intracellular activities in addition to the membrane permeabilization mode of action reported earlier. In conclusion, AamAP1-Lysine could prove to be a potential candidate for antimicrobial drug development in future studies.

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

    Science.gov (United States)

    Rollins-Smith, Louise A

    2009-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Buckholtz, Gavin A.; Reger, Nina A. [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); Anderton, William D.; Schimoler, Patrick J. [Orthopaedic Biomechanics Research Laboratory, Allegheny General Hospital, Pittsburgh, PA 15212 (United States); Roudebush, Shana L.; Meng, Wilson S. [Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282 (United States); Miller, Mark C. [Orthopaedic Biomechanics Research Laboratory, Allegheny General Hospital, Pittsburgh, PA 15212 (United States); Gawalt, Ellen S., E-mail: gawalte@duq.edu [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219 (United States)

    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 24 h) 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. - Highlights: • Calcium aluminum oxide and hydroxyapatite were cast into a composite material. • Osteoblast attachment and proliferation were significantly increased on composites. • An active antimicrobial peptide was linked to and remained stable on the composite. • Bacterial turbidity and NPN uptake tests showed modified composites had an effect equal to a 10 μM Inverso-CysHHC10 solution. • Antimicrobial peptide linkage did not affect the increased osteoblast performance.

  19. 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...

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

    Directory of Open Access Journals (Sweden)

    Shawn eLewenza

    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.

  1. Prediction, production and characterization of post-translationally modified antimicrobial peptides

    NARCIS (Netherlands)

    van Heel, Auke Johan

    2016-01-01

    Pathogenic bacteria are rapidly becoming resistant to the currently used antibiotics therefore we need novel antibiotics, preferably with new mechanisms of action. One potential source are the so called antimicrobial peptides that are produced by many different organisms. To gain access to these pot

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

    NARCIS (Netherlands)

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

    1995-01-01

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

  3. 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

  4. 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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  6. Antimicrobial properties of a lipid interactive -helical peptide VP1 against Staphylococcus aureus bacteria

    OpenAIRE

    Dennison, Sarah R.; Morton, Leslie H.G.; Harris, Frederick; Phoenix, David A.

    2007-01-01

    Antimicrobial properties of a lipid interactive -helical peptide VP1 against Staphylococcus aureus bacteria correspondance: Corresponding author. Tel: +44 1772 893481; fax: +44 1772 894981. (Phoenix, David A.) (Phoenix, David A.) Faculty of Science and Technology--> , University of Central Lancashire--> , Preston PR1 2HE--> - UNITED KINGDOM (Dennison, Sarah R) Department of Forensic and Inve...

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    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...

  8. Purification and characterization of an antimicrobial peptide produced by Bacillus sp. strain P7

    OpenAIRE

    Fernández Soto, Paulina Alexandra

    2014-01-01

    This study reports a potential novel antimicrobial peptide with narrow spectrum activity against S. aureus NCTC 7447, produced by Bacillus tequilensis. Further studies to improve AMP-P7 purification and characterization are requered to establish its potential used in medicine and industry.

  9. Antimicrobial peptides with therapeutic potential from skin secretions of polyploid frogs of the Pipidae family

    NARCIS (Netherlands)

    Mechkarska, M.P.M.

    2013-01-01

    The emergence of pathogenic bacteria and fungi resistant to commonly used antibiotics poses a serious threat to public health and necessitates novel treatment approaches in order to control infections. Antimicrobial peptides (AMPs) are one of the central components of the system of innate immunity a

  10. 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

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

    Science.gov (United States)

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

  12. 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

  13. Antimicrobial Properties of Mesenchymal Stem Cells: Therapeutic Potential for Cystic Fibrosis Infection, and Treatment

    Directory of Open Access Journals (Sweden)

    Morgan T. Sutton

    2016-01-01

    Full Text Available Cystic fibrosis (CF is a genetic disease in which the battle between pulmonary infection and inflammation becomes the major cause of morbidity and mortality. We have previously shown that human MSCs (hMSCs decrease inflammation and infection in the in vivo murine model of CF. The studies in this paper focus on the specificity of the hMSC antimicrobial effectiveness using Pseudomonas aeruginosa (gram negative bacteria and Staphylococcus aureus (gram positive bacteria. Our studies show that hMSCs secrete bioactive molecules which are antimicrobial in vitro against Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pneumonia, impacting the rate of bacterial growth and transition into colony forming units regardless of the pathogen. Further, we show that the hMSCs have the capacity to enhance antibiotic sensitivity, improving the capacity to kill bacteria. We present data which suggests that the antimicrobial effectiveness is associated with the capacity to slow bacterial growth and the ability of the hMSCs to secrete the antimicrobial peptide LL-37. Lastly, our studies demonstrate that the tissue origin of the hMSCs (bone marrow or adipose tissue derived, the presence of functional cystic fibrosis transmembrane conductance regulator (CFTR: human, Cftr: mouse activity, and response to effector cytokines can impact both hMSC phenotype and antimicrobial potency and efficacy. These studies demonstrate, the unique capacity of the hMSCs to manage different pathogens and the significance of their phenotype in both the antimicrobial and antibiotic enhancing activities.

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

    Directory of Open Access Journals (Sweden)

    Natascia Bruni

    2016-06-01

    Full Text Available 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.

  15. Peripheral and integral membrane binding of peptides characterized by time-dependent fluorescence shifts: focus on antimicrobial peptide LAH₄.

    Science.gov (United States)

    Macháň, Radek; Jurkiewicz, Piotr; Olżyńska, Agnieszka; Olšinová, Marie; Cebecauer, Marek; Marquette, Arnaud; Bechinger, Burkhard; Hof, Martin

    2014-06-03

    Positioning of peptides with respect to membranes is an important parameter for biological and biophysical studies using model systems. Our experiments using five different membrane peptides suggest that the time-dependent fluorescence shift (TDFS) of Laurdan can help when distinguishing between peripheral and integral membrane binding and can be a useful, novel tool for studying the impact of transmembrane peptides (TMP) on membrane organization under near-physiological conditions. This article focuses on LAH4, a model α-helical peptide with high antimicrobial and nucleic acid transfection efficiencies. The predominantly helical peptide has been shown to orient in supported model membranes parallel to the membrane surface at acidic and, in a transmembrane manner, at basic pH. Here we investigate its interaction with fully hydrated large unilamellar vesicles (LUVs) by TDFS and fluorescence correlation spectroscopy (FCS). TDFS shows that at acidic pH LAH4 does not influence the glycerol region while at basic pH it makes acyl groups at the glycerol level of the membrane less mobile. TDFS experiments with antimicrobial peptides alamethicin and magainin 2, which are known to assume transmembrane and peripheral orientations, respectively, prove that changes in acyl group mobility at the glycerol level correlate with the orientation of membrane-associated peptide molecules. Analogous experiments with the TMPs LW21 and LAT show similar effects on the mobility of those acyl groups as alamethicin and LAH4 at basic pH. FCS, on the same neutral lipid bilayer vesicles, shows that the peripheral binding mode of LAH4 is more efficient in bilayer permeation than the transmembrane mode. In both cases, the addition of LAH4 does not lead to vesicle disintegration. The influence of negatively charged lipids on the bilayer permeation is also addressed.

  16. Antimicrobial peptides with atypical structural features from the skin of the Japanese brown frog Rana japonica.

    Science.gov (United States)

    Isaacson, Todd; Soto, AnaMaria; Iwamuro, Shawichi; Knoop, Floyd C; Conlon, J Michael

    2002-03-01

    Japonicin-1 (FFPIGVFCKIFKTC) and japonicin-2 (FGLPMLSILPKALCILLKRKC), two peptides with differential growth-inhibitory activity against the Gram-negative bacterium, Escherichia coli and the Gram-positive bacterium Staphylococcus aureus, were isolated from an extract of the skin of the Japanese brown frog Rana japonica. Both peptides show little amino acid sequence similarity to previously characterized antimicrobial peptides isolated from the skins of Ranid frogs. Circular dichroism studies, however, demonstrate that japonicin-2 adopts an alpha-helical conformation in 50% trifluoroethanol in common with many other cationic antimicrobial peptides synthesized in amphibian skin. Peptides belonging to the brevinin-1, brevinin-2, and tigerinin families, previously identified in the skins of Asian Ranid frogs, were not detected but a temporin-related peptide (ILPLVGNLLNDLL.NH(2); temporin-1Ja), that atypically bears no net positive charge, was isolated from the extract. The minimum inhibitory concentrations (MICs) of the peptides against E. coli were japonicin-1, 30 microM; japonicin-2, 12 microM; and temporin-1Ja > 100 microM. The MICs against S. aureus were japonicin-1, > 100 microM; japonicin-2, 20 microM; and temporin-1Ja, > 100 microM.

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

    Science.gov (United States)

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

    2011-12-12

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

  18. Generation of novel cationic antimicrobial peptides from natural non-antimicrobial sequences by acid-amide substitution

    Directory of Open Access Journals (Sweden)

    Tamada Yasushi

    2011-03-01

    Full Text Available Abstract Background Cationic antimicrobial peptides (CAMPs are well recognized to be promising as novel antimicrobial and antitumor agents. To obtain novel skeletons of CAMPs, we propose a simple strategy using acid-amide substitution (i.e. Glu→Gln, Asp→Asn to confer net positive charge to natural non-antimicrobial sequences that have structures distinct from known CAMPs. The potential of this strategy was verified by a trial study. Methods The pro-regions of nematode cecropin P1-P3 (P1P-P3P were selected as parent sequences. P1P-P3P and their acid-amide-substituted mutants (NP1P-NP3P were chemically synthesized. Bactericidal and membrane-disruptive activities of these peptides were evaluated. Conformational changes were estimated from far-ultraviolet circular dichroism (CD spectra. Results NP1P-NP3P acquired potent bactericidal activities via membrane-disruption although P1P-P3P were not antimicrobial. Far-ultraviolet CD spectra of NP1P-NP3P were similar to those of their parent peptides P1P-P3P, suggesting that NP1P-NP3P acquire microbicidal activity without remarkable conformational changes. NP1P-NP3P killed bacteria in almost parallel fashion with their membrane-disruptive activities, suggesting that the mode of action of those peptides was membrane-disruption. Interestingly, membrane-disruptive activity of NP1P-NP3P were highly diversified against acidic liposomes, indicating that the acid-amide-substituted nematode cecropin pro-region was expected to be a unique and promising skeleton for novel synthetic CAMPs with diversified membrane-discriminative properties. Conclusions The acid-amide substitution successfully generated some novel CAMPs in our trial study. These novel CAMPs were derived from natural non-antimicrobial sequences, and their sequences were completely distinct from any categories of known CAMPs, suggesting that such mutated natural sequences could be a promising source of novel skeletons of CAMPs.

  19. 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.

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

    Science.gov (United States)

    Hancock, Robert E W; Sahl, Hans-Georg

    2006-12-01

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

  1. Extremely abundant antimicrobial peptides existed in the skins of nine kinds of Chinese odorous frogs.

    Science.gov (United States)

    Yang, Xinwang; Lee, Wen-Hui; Zhang, Yun

    2012-01-01

    Peptide agents are regarded as hopeful candidates to solve life-threatening resistance of pathogenic microorganisms to classic antibiotics due to their unique action mechanisms. Peptidomic and genomic investigation of natural antimicrobial peptides (AMPs) from amphibian skin secretions can provide a large amount of structure-functional information to design peptide antibiotics with therapeutic potential. In the present study, we identified a large number of AMPs from the skins of nine kinds of Chinese odorous frogs. Eighty AMPs were purified from three different odorous frogs and confirmed by peptidomic analysis. Our results indicated that post-translational modification of AMPs rarely happened in odorous frogs. cDNAs encoding precursors of 728 AMPs, including all the precursors of the confirmed 80 native peptides, were cloned from the constructed AMP cDNA libraries of nine Chinese odorous frogs. On the basis of the sequence similarity of deduced mature peptides, these 728 AMPs were grouped into 97 different families in which 71 novel families were identified. Out of these 728 AMPs, 662 AMPs were novel and 28 AMPs were reported previously in other frog species. Our results revealed that identical AMPs were widely distributed in odorous frogs; 49 presently identified AMPs could find their identical molecules in different amphibian species. Purified peptides showed strong antimicrobial activities against 4 tested microbe strains. Twenty-three deduced peptides were synthesized and their bioactivities, including antimicrobial, antioxidant, hemolytic, immunomodulatory and insulin-releasing activities, were evaluated. Our findings demonstrate the extreme diversity of AMPs in amphibian skins and provide plenty of templates to develop novel peptide antibiotics.

  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. Three novel antimicrobial peptides from the skin of the Indian bronzed frog Hylarana temporalis (Anura: Ranidae).

    Science.gov (United States)

    Reshmy, V; Preeji, V; Parvin, A; Santhoshkumar, K; George, S

    2011-05-01

    Amphibian skin secretion is considered as a rich source of bioactive peptides. The present work describes the successful identification of three novel peptides named brevinin-1TEa, brevinin-2TEa and brevinin-2TEb present in the skin secretion of Indian bronzed frog Hylarana temporalis. The deduced open reading frame encoding the biosynthetic precursor of brevinin-1TEa consisted of 70 amino acid residues and brevinin-2TEa and brevinin-2TEb consisted of 71 and 72 amino acids, respectively. All the three peptides showed higher antimicrobial activity against Gram-negative than against Gram-positive bacteria. On the basis of the antibacterial and haemolytic activity, brevinin-2TEb is the most potent peptide reported in the present study. Further research on these peptides may provide potential clue towards newer drug development to combat various microbial diseases.

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

    Science.gov (United States)

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

    2014-10-01

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

  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. pH Dependence of microbe sterilization by cationic antimicrobial peptides.

    Science.gov (United States)

    Walkenhorst, William F; Klein, J Wolfgang; Vo, Phuong; Wimley, William C

    2013-07-01

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

  7. 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.

  8. [High expression of antimicrobial peptide Cecropin AD in Escherichia coli by fusion with EDDIE].

    Science.gov (United States)

    Zhang, Zhen; Ke, Tao; Zhou, Yuling; Ma, Xiangdong; Ma, Lixin

    2009-08-01

    In this study, we efficiently expressed the active antimicrobial peptide (CAD), which fused with the site-mutated coat protein (EDDIE) of the classical swine fever virus, in Escherichia coli. First, we obtained the e-cad fusion gene from the CAD gene and the EDDIE gene using overlapping PCR. Then to get the recombinant expression vector (pETED), the e-cad fusion gene was cloned into the pET30a vector by a site-directed homologous recombination technique. The EDDIE-CAD fusion protein expressed in E. coli as inclusion bodies, and its yield was more than 40% of total bacterial proteins. After renaturated in vitro and self-cleavage of the fusion protein, we obtained the antimicrobial peptide Cecropin AD. Antimicrobial experiments showed that the Cecropin AD efficiently inhibited the growth of G+ and G- bacteria, but it weakly inhibited the growth of Saccharomyces. This method provides an excellent way for high expression of antimicrobial peptides when fused with EDDIE.

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

    DEFF Research Database (Denmark)

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

    2006-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Haitham Ahmed Yacoub

    2015-04-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  12. Antimicrobial peptides from marine invertebrates as a new frontier for microbial infection control.

    Science.gov (United States)

    Otero-González, Anselmo Jesus; Magalhães, Beatriz Simas; Garcia-Villarino, Monica; López-Abarrategui, Carlos; Sousa, Daniel Amaro; Dias, Simoni Campos; Franco, Octávio Luiz

    2010-05-01

    Antimicrobial peptides are widely expressed in organisms and have been linked to innate and acquired immunities in vertebrates. These compounds are constitutively expressed and rapidly induced at different cellular levels to interact directly with infectious agents and/or modulate immunoreactions involved in defense against pathogenic microorganisms. In invertebrates, antimicrobial peptides represent the major humoral defense system against infection, showing a diverse spectrum of action mechanisms, most of them related to plasma membrane disturbance and lethal alteration of microbial integrity. Marine invertebrates are widespread, extremely diverse, and constantly under an enormous microbial challenge from the ocean environment, itself altered by anthropic influences derived from industrialization and transportation. Consequently, this study reexamines the peptides isolated over the past 2 decades from different origins, bringing phyla not previously reviewed up to date. Moreover, a promising novel use of antimicrobial peptides as effective drugs in human and veterinary medicine could be based on their unusual properties and synergic counterparts as immune response humoral effectors, in addition to their direct microbicidal activity. This has been seen in many other marine proteins that are sufficiently immunogenic to humans, not necessarily in terms of antibody generation but as inflammation promoters and recruitment agents or immune enhancers.

  13. Penaeidins, a new family of antimicrobial peptides isolated from the shrimp Penaeus vannamei (Decapoda).

    Science.gov (United States)

    Destoumieux, D; Bulet, P; Loew, D; Van Dorsselaer, A; Rodriguez, J; Bachère, E

    1997-11-07

    We report here the isolation of three members of a new family of antimicrobial peptides from the hemolymph of shrimps Penaeus vannamei in which immune response has not been experimentally induced. The three molecules display antimicrobial activity against fungi and bacteria with a predominant activity against Gram-positive bacteria. The complete sequences of these peptides were determined by a combination of enzymatic cleavages, Edman degradation, mass spectrometry, and cDNA cloning using a hemocyte cDNA library. The mature molecules (50 and 62 residues) are characterized by an NH2-terminal domain rich in proline residues and a COOH-terminal domain containing three intramolecular disulfide bridges. One of these molecules is post-translationally modified by a pyroglutamic acid at the first position. Comparison of the data obtained from the cDNA clones and mass spectrometry showed that two of these peptides are probably COOH-terminally amidated by elimination of a glycine residue. These molecules with no evident homology to other hitherto described antimicrobial peptides were named penaeidins.

  14. Trichoplaxin - a new membrane-active antimicrobial peptide from placozoan cDNA.

    Science.gov (United States)

    Simunić, Juraj; Petrov, Dražen; Bouceba, Tahar; Kamech, Nédia; Benincasa, Monica; Juretić, Davor

    2014-05-01

    A method based on the use of signal peptide sequences from antimicrobial peptide (AMP) precursors was used to mine a placozoa expressed sequence tag database and identified a potential antimicrobial peptide from Trichoplax adhaerens. This peptide, with predicted sequence FFGRLKSVWSAVKHGWKAAKSR is the first AMP from a placozoan species, and was named trichoplaxin. It was chemically synthesized and its structural properties, biological activities and membrane selectivity were investigated. It adopts an α-helical structure in contact with membrane-like environments and is active against both Gram-negative and Gram-positive bacterial species (including MRSA), as well as yeasts from the Candida genus. The cytotoxic activity, as assessed by the haemolytic activity against rat erythrocytes, U937 cell permeabilization to propidium iodide and MCF7 cell mitochondrial activity, is significantly lower than the antimicrobial activity. In tests with membrane models, trichoplaxin shows high affinity for anionic prokaryote-like membranes with good fit in kinetic studies. Conversely, there is a low affinity for neutral eukaryote-like membranes and absence of a dose dependent response. With high selectivity for bacterial cells and no homologous sequence in the UniProt, trichoplaxin is a new potential lead compound for development of broad-spectrum antibacterial drugs.

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

    Science.gov (United States)

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

    2009-08-01

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

  16. 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...... optimization is needed if AMPs are to find broad use as antibiotics. In the present work, eight analogues of mastoparan-X (MPX) were investigated, having side chain modifications in position 1, 8 and 14 to modulate peptide hydrophobicity. The self-association properties of the peptides were characterized...... in target selectivity correlated to biophysical parameters showing an increased effective charge and reduction in the partitioning coefficient for membrane insertion. Introduction of an unnatural amino acid, with an octyl side chain by amino acid substitution, at positions 1, 8 and 14 resulted in increased...

  17. 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.

  18. A cactus-derived toxin-like cystine knot Peptide with selective antimicrobial activity.

    Science.gov (United States)

    Aboye, Teshome L; Strömstedt, Adam A; Gunasekera, Sunithi; Bruhn, Jan G; El-Seedi, Hesham; Rosengren, K Johan; Göransson, Ulf

    2015-05-04

    Naturally occurring cystine knot peptides show a wide range of biological activity, and as they have inherent stability they represent potential scaffolds for peptide-based drug design and biomolecular engineering. Here we report the discovery, sequencing, chemical synthesis, three-dimensional solution structure determination and bioactivity of the first cystine knot peptide from Cactaceae (cactus) family: Ep-AMP1 from Echinopsis pachanoi. The structure of Ep-AMP1 (35 amino acids) conforms to that of the inhibitor cystine knot (or knottin) family but represents a novel diverse sequence; its activity was more than 500 times higher against bacterial than against eukaryotic cells. Rapid bactericidal action and liposome leakage implicate membrane permeabilisation as the mechanism of action. Sequence homology places Ec-AMP1 in the plant C6-type of antimicrobial peptides, but the three dimensional structure is highly similar to that of a spider neurotoxin.

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

    Science.gov (United States)

    Hiemstra, Pieter S

    2015-11-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2014-05-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-05-01

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

  4. Differential effects of alpha-helical and beta-hairpin antimicrobial peptides against Acanthamoeba castellanii.

    Science.gov (United States)

    Sacramento, R S; Martins, R M; Miranda, A; Dobroff, A S S; Daffre, S; Foronda, A S; De Freitas, D; Schenkman, S

    2009-07-01

    In this work we evaluated the ability of different types of antimicrobial peptides to promote permeabilization and growth inhibition of Acanthamoeba castellanii trophozoites, which cause eye keratitis. We used cationic alpha-helical peptides P5 and P6, corresponding to the N-terminus of the pore-forming protein from Triatoma infestans, a blood-sucking insect, and a beta-hairpin amphipathic molecule (gomesin), of the spider Acanthoscurria gomesiana haemocytes. A. castellanii permeabilization was obtained after 1 h incubation with micromolar concentrations of both types of peptides. While permeabilization induced by gomesin increased with longer incubations, P5 permeabilization did not increase with time and occurred at doses that are more toxic for SIRC cells. P5, however, at doses below the critical dose used to kill rabbit corneal cells was quite effective in promoting growth inhibition. Similarly, P5 was more effective when serine protease inhibitor was added simultaneously to the permeabilization assay. High performance chromatography followed by mass spectrometry analysis confirmed that, in contrast to gomesin, P5 is hydrolysed by A. castellanii culture supernatants. We conclude that the use of antimicrobial peptides to treat A. castellanii infections requires the search of more specific peptides that are resistant to proteolysis.

  5. Potent antimicrobial peptides against Legionella pneumophila and its environmental host, Acanthamoeba castellanii.

    Science.gov (United States)

    Schlusselhuber, Margot; Humblot, Vincent; Casale, Sandra; Méthivier, Christophe; Verdon, Julien; Leippe, Matthias; Berjeaud, Jean-Marc

    2015-06-01

    Legionella pneumophila, the major causative agent of Legionnaires' disease, is most often found in the environment in close association with free-living amoebae, leading to persistence, spread, biocide resistance, and elevated virulence of the bacterium. In the present study, we evaluated the anti-Legionella and anti-Acanthamoeba activities of three alpha-helical antimicrobial peptides (AMPs), namely, NK-2, Ci-MAM-A24, and Ci-PAP-A22, already known for the extraordinary efficacy against other microbes. Our data represent the first demonstration of the activity of a particular AMP against both the human facultative intracellular pathogen L. pneumophila and its pathogenic host, Acanthamoeba castellanii. Interestingly, the most effective peptide, Ci-MAM-A24, was also found to reduce the Legionella cell number within amoebae. Accordingly, this peptide was immobilized on gold surfaces to assess its antimicrobial activity. Surfaces were characterized, and activity studies revealed that the potent bactericidal activity of the peptide was conserved after its immobilization. In the frame of elaborating anti-Legionella surfaces, Ci-MAM-A24 represents, by its direct and indirect activity against Legionella, a potent peptide template for biological control of the bacterium in plumbings.

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

    Science.gov (United States)

    Wang, Guangshun; Li, Xia; Wang, Zhe

    2016-01-04

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

  7. Comparison of antibacterial effects between antimicrobial peptide and bacteriocins isolated from Lactobacillus plantarum on three common pathogenic bacteria

    OpenAIRE

    Ming, Liu; Zhang, Qian; Yang, Le; Huang, Jian-An

    2015-01-01

    New strategies for the prevention or treatment of infections are required. The purpose of this study is to evaluate the effects of antimicrobial peptides and bacteriocins isolated from Lactobacillus plantarum on growth and biofilm formation of three common pathogenic microbes. The antibacterial properties of the antimicrobial peptide Tet213 and bacteriocins were tested by the disc diffusion method. Tet213 and bacteriocins showed inhibitory effects on biofilm formation for the three organisms,...

  8. Host defence peptides: antimicrobial and immunomodulatory activity and potential applications for tackling antibiotic-resistant infections

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available

    The rapidly increasing incidence of multidrug-resistant infections and the alarmingly low rate of discovery of conventional antibiotics create an urgent need for alternative strategies to treat bacterial infections. Host defence peptides are short cationic molecules produced by the immune systems of most multicellular organisms; they are a class of compounds being actively researched. In this review, we provide an overview of the antimicrobial and immunomodulatory activities of natural host defence peptides, and discuss strategies for creating artificial derivatives with improved biological and pharmacological properties, issues of microbial resistance, and challenges associated with their adaptation for clinical use.

  9. Antimicrobial peptides as parasiticidal against human trypanosomatids: mechanisms of action and current status in development.

    Science.gov (United States)

    Méndez-Samperio, P; de-la-Rosa-Arana, J L

    2013-04-01

    Trypanosomes cause a variety of tropical diseases that affect the livelihood of individuals worldwide. The currently used pharmaceutical treatments rely on chemotherapy. However, many of these drugs are very expensive, and highly toxic. In addition, parasite resistance to several of the therapeutic drugs used is increasing. Therefore, there is a growing need for new control measures for many of these diseases. One new approach is the use of antimicrobial peptides (AMPs) to disease control, since these peptides can be used as potential anti-parasite effector molecules. This review summarizes and discusses the parasiticidal properties of AMPs for treating trypanosome infections, highlighting their mechanisms of action and current status in development.

  10. Selection of Small Synthetic Antimicrobial Peptides Inhibiting Xanthomonas citri subsp. citri Causing Citrus Canker

    Science.gov (United States)

    Choi, Jeahyuk; Park, Euiho; Lee, Se-Weon; Hyun, Jae-Wook; Baek, Kwang-Hyun

    2017-01-01

    Citrus canker disease decreases the fruit quality and yield significantly, furthermore, emerging of streptomycin-resistant pathogens threatens the citrus industry seriously because of a lack of proper control agents. Small synthetic antimicrobial peptides (AMPs) could be a promising alternative. Fourteen hexapeptides were selected by using positional scanning of synthetic peptide combinatorial libraries. Each hexapeptide showed different antimicrobial spectrum against Bacillus, Pseudomonas, Xanthomonas, and Candida species. Intriguingly, BHC10 showed bactericidal activity exclusively on Xanthomonas citri subsp. citri (Xcc), while BHC7 was none-active exclusively against two Pseudomonas spp. at concentration of 100 μg/ml suggesting potential selectivity constrained in hexapeptide frame. Three hexapeptides, BHC02, 06 and 11, showed bactericidal activities against various Xcc strains at concentration of 10 μg/ml. When they were co-infiltrated with pathogens into citrus leaves the disease progress was suppressed significantly. Further study would be needed to confirm the actual disease control capacity of the selected hexapeptides. PMID:28167892

  11. Chemical and genetic characterization of bacteriocins: antimicrobial peptides for food safety.

    Science.gov (United States)

    Snyder, Abigail B; Worobo, Randy W

    2014-01-15

    Antimicrobial peptides are produced across all domains of life. Among these diverse compounds, those produced by bacteria have been most successfully applied as agents of biocontrol in food and agriculture. Bacteriocins are ribosomally synthesized, proteinaceous compounds that inhibit the growth of closely related bacteria. Even within the subcategory of bacteriocins, the peptides vary significantly in terms of the gene cluster responsible for expression, and chemical and structural composition. The polycistronic gene cluster generally includes a structural gene and various combinations of immunity, secretion, and regulatory genes and modifying enzymes. Chemical variation can exist in amino acid identity, chain length, secondary and tertiary structural features, as well as specificity of active sites. This diversity posits bacteriocins as potential antimicrobial agents with a range of functions and applications. Those produced by food-grade bacteria and applied in normally occurring concentrations can be used as GRAS-status food additives. However, successful application requires thorough characterization.

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

    Science.gov (United States)

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

    2014-05-01

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

  13. The Role of Biophysical Parameters in the Antilipopolysaccharide Activities of Antimicrobial Peptides from Marine Fish

    Directory of Open Access Journals (Sweden)

    Ramamourthy Gopal

    2014-03-01

    Full Text Available Numerous antimicrobial peptides (AMPs from marine fish have been identified, isolated and characterized. These peptides act as host defense molecules that exert antimicrobial effects by targeting the lipopolysaccharide (LPS of Gram-negative bacteria. The LPS-AMP interactions are driven by the biophysical properties of AMPs. In this review, therefore, we will focus on the physiochemical properties of AMPs; that is, the contributions made by their sequences, net charge, hydrophobicity and amphipathicity to their mechanism of action. Moreover, the interactions between LPS and fish AMPs and the structure of fish AMPs with LPS bound will also be discussed. A better understanding of the biophysical properties will be useful in the design of AMPs effective against septic shock and multidrug-resistant bacterial strains, including those that commonly produce wound infections.

  14. pH Dependent Antimicrobial Peptides and Proteins, Their Mechanisms of Action and Potential as Therapeutic Agents

    OpenAIRE

    2016-01-01

    Antimicrobial peptides (AMPs) are potent antibiotics of the innate immune system that have been extensively investigated as a potential solution to the global problem of infectious diseases caused by pathogenic microbes. A group of AMPs that are increasingly being reported are those that utilise pH dependent antimicrobial mechanisms, and here we review research into this area. This review shows that these antimicrobial molecules are produced by a diverse spectrum of creatures, including verte...

  15. Antimicrobial Peptides from Fruits and Their Potential Use as Biotechnological Tools—A Review and Outlook

    Science.gov (United States)

    Meneguetti, Beatriz T.; Machado, Leandro dos Santos; Oshiro, Karen G. N.; Nogueira, Micaella L.; Carvalho, Cristiano M. E.; Franco, Octávio L.

    2017-01-01

    Bacterial resistance is a major threat to plant crops, animals and human health, and over the years this situation has increasingly spread worldwide. Due to their many bioactive compounds, plants are promising sources of antimicrobial compounds that can potentially be used in the treatment of infections caused by microorganisms. As well as stem, flowers and leaves, fruits have an efficient defense mechanism against pests and pathogens, besides presenting nutritional and functional properties due to their multifunctional molecules. Among such compounds, the antimicrobial peptides (AMPs) feature different antimicrobials that are capable of disrupting the microbial membrane and of acting in binding to intra-cytoplasmic targets of microorganisms. They are therefore capable of controlling or halting the growth of microorganisms. In summary, this review describes the major classes of AMPs found in fruits, their possible use as biotechnological tools and prospects for the pharmaceutical industry and agribusiness. PMID:28119671

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

    Science.gov (United States)

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

    2010-09-01

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

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

    OpenAIRE

    Dover, Sara E.; Aroutcheva, Alla A.; Faro, S; 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...

  18. Increased survival of experimentally evolved antimicrobial peptide-resistant Staphylococcus aureus in an animal host.

    Science.gov (United States)

    Dobson, Adam J; Purves, Joanne; Rolff, Jens

    2014-09-01

    Antimicrobial peptides (AMPs) have been proposed as new class of antimicrobial drugs, following the increasing prevalence of bacteria resistant to antibiotics. Synthetic AMPs are functional analogues of highly evolutionarily conserved immune effectors in animals and plants, produced in response to microbial infection. Therefore, the proposed therapeutic use of AMPs bears the risk of 'arming the enemy': bacteria that evolve resistance to AMPs may be cross-resistant to immune effectors (AMPs) in their hosts. We used a panel of populations of Staphylococcus aureus that were experimentally selected for resistance to a suite of individual AMPs and antibiotics to investigate the 'arming the enemy' hypothesis. We tested whether the selected strains showed higher survival in an insect model (Tenebrio molitor) and cross-resistance against other antimicrobials in vitro. A population selected for resistance to the antimicrobial peptide iseganan showed increased in vivo survival, but was not more virulent. We suggest that increased survival of AMP-resistant bacteria almost certainly poses problems to immune-compromised hosts.

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

    Directory of Open Access Journals (Sweden)

    Shuai Wang

    2016-05-01

    Full Text Available Over the last decade, the rapid emergence of multidrug-resistant pathogens has become a global concern, which has prompted the search for alternative antibacterial agents for use in food animals. Antimicrobial peptides (AMPs, produced by bacteria, insects, amphibians and mammals, as well as by chemical synthesis, are possible candidates for the design of new antimicrobial agents because of their natural antimicrobial properties and a low propensity for development of resistance by microorganisms. This manuscript reviews the current knowledge of the basic biology of AMPs and their applications in non-ruminant nutrition. Antimicrobial peptides not only have broad-spectrum activity against bacteria, fungi, and viruses but also have the ability to bypass the common resistance mechanisms that are placing standard antibiotics in jeopardy. In addition, AMPs have beneficial effects on growth performance, nutrient digestibility, intestinal morphology and gut microbiota in pigs and broilers. Therefore, AMPs have good potential as suitable alternatives to conventional antibiotics used in swine and poultry industries.

  20. Marine Antimicrobial Peptides: Nature Provides Templates for the Design of Novel Compounds against Pathogenic Bacteria

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    Annarita Falanga

    2016-05-01

    Full Text Available 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.

  1. Antimicrobial peptides of the genus Bacillus: a new era for antibiotics.

    Science.gov (United States)

    Sumi, Chandra Datta; Yang, Byung Wook; Yeo, In-Cheol; Hahm, Young Tae

    2015-02-01

    The rapid onset of resistance reduces the efficacy of most conventional antimicrobial drugs and is a general cause of concern for human well-being. Thus, there is great demand for a continuous supply of novel antibiotics to combat this problem. Bacteria-derived antimicrobial peptides (AMPs) have long been used as food preservatives; moreover, prior to the development of conventional antibiotics, these AMPs served as an efficient source of antibiotics. Recently, peptides produced by members of the genus Bacillus were shown to have a broad spectrum of antimicrobial activity against pathogenic microbes. Bacillus-derived AMPs can be synthesized both ribosomally and nonribosomally and can be classified according to peptide biosynthesis, structure, and molecular weight. The precise mechanism of action of these AMPs is not yet clear; however, one proposed mechanism is that these AMPs kill bacteria by forming channels in and (or) disrupting the bacterial cell wall. Bacillus-derived AMPs have potential in the pharmaceutical industry, as well as the food and agricultural sectors. Here, we focus on Bacillus-derived AMPs as a novel alternative approach to antibacterial drug development. We also provide an overview of the biosynthesis, mechanisms of action, applications, and effectiveness of different AMPs produced by members of the Bacillus genus, including several recently identified novel AMPs.

  2. Screening, Expression, Purification and Functional Characterization of Novel Antimicrobial Peptide Genes from Hermetia illucens (L.)

    Science.gov (United States)

    Elhag, Osama; Zhou, Dingzhong; Song, Qi; Soomro, Abdul Aziz; Cai, Minmin; Zheng, Longyu; Yu, Ziniu; Zhang, Jibin

    2017-01-01

    Antimicrobial peptides from a wide spectrum of insects possess potent microbicidal properties against microbial-related diseases. In this study, seven new gene fragments of three types of antimicrobial peptides were obtained from Hermetia illucens (L), and were named cecropinZ1, sarcotoxin1, sarcotoxin (2a), sarcotoxin (2b), sarcotoxin3, stomoxynZH1, and stomoxynZH1(a). Among these genes, a 189-basepair gene (stomoxynZH1) was cloned into the pET32a expression vector and expressed in the Escherichia coli as a fusion protein with thioredoxin. Results show that Trx-stomoxynZH1 exhibits diverse inhibitory activity on various pathogens, including Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli, fungus Rhizoctonia solani Khün (rice)-10, and fungus Sclerotinia sclerotiorum (Lib.) de Bary-14. The minimum inhibitory concentration of Trx-stomoxynZH1 is higher against Gram-positive bacteria than against Gram-negative bacteria but similar between the fungal strains. These results indicate that H. illucens (L.) could provide a rich source for the discovery of novel antimicrobial peptides. Importantly, stomoxynZH1 displays a potential benefit in controlling antibiotic-resistant pathogens. PMID:28056070

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

    Science.gov (United States)

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

    2002-03-15

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

  4. Activity and Mechanism of Antimicrobial Peptide-Mimetic Amphiphilic Polymethacrylate Derivatives

    Directory of Open Access Journals (Sweden)

    Kenichi Kuroda

    2011-09-01

    Full Text Available Cationic amphiphilic polymethacrylate derivatives (PMAs have shown potential as a novel class of synthetic antimicrobials. A panel of PMAs with varied ratios of hydrophobic and cationic side chains were synthesized and tested for antimicrobial activity and mechanism of action. The PMAs are shown to be active against a panel of pathogenic bacteria, including a drug-resistant Staphylococcus aureus, compared to the natural antimicrobial peptide magainin which did not display any activity against the same strain. The selected PMAs with 47–63% of methyl groups in the side chains showed minimum inhibitory concentrations of ≤2–31 µg/mL, but cause only minimal harm to human red blood cells. The PMAs also exhibit rapid bactericidal kinetics. Culturing Escherichia coli in the presence of the PMAs did not exhibit any potential to develop resistance against the PMAs. The antibacterial activities of PMAs against E. coli and S. aureus were slightly reduced in the presence of physiological salts. The activity of PMAs showed bactericidal effects against E. coli and S. aureus in both exponential and stationary growth phases. These results demonstrate that PMAs are a new antimicrobial platform with no observed development of resistance in bacteria. In addition, the PMAs permeabilized the E. coli outer membrane at polymer concentrations lower than their MIC values, but they did not show any effect on the bacterial inner membrane. This indicates that mechanisms other than membrane permeabilization may be the primary factors determining their antimicrobial activity.

  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. Species-selective killing of bacteria by antimicrobial peptide-PNAs.

    Directory of Open Access Journals (Sweden)

    Madhav Mondhe

    Full Text Available Broad-spectrum antimicrobials kill indiscriminately, a property that can lead to negative clinical consequences and an increase in the incidence of resistance. Species-specific antimicrobials that could selectively kill pathogenic bacteria without targeting other species in the microbiome could limit these problems. The pathogen genome presents an excellent target for the development of such antimicrobials. In this study we report the design and evaluation of species-selective peptide nucleic acid (PNA antibacterials. Selective growth inhibition of B. subtilis, E. coli, K. pnuemoniae and S. enterica serovar Typhimurium in axenic or mixed culture could be achieved with PNAs that exploit species differences in the translation initiation region of essential genes. An S. Typhimurium-specific PNA targeting ftsZ resulted in elongated cells that were not observed in E. coli, providing phenotypic evidence of the selectivity of PNA-based antimicrobials. Analysis of the genomes of E. coli and S. Typhimurium gave a conservative estimate of >150 PNA targets that could potentially discriminate between these two closely related species. This work provides a basis for the development of a new class of antimicrobial with a tuneable spectrum of activity.

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

    Science.gov (United States)

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

    2009-08-01

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

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

    NARCIS (Netherlands)

    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

  9. Identification of a Novel Proline-Rich Antimicrobial Peptide from Brassica napus.

    Directory of Open Access Journals (Sweden)

    Huihui Cao

    Full Text Available Proline-rich antimicrobial peptides (PR-AMPs are a group of cationic host defense peptides that are characterized by a high content of proline residues. Up to now, they have been reported in some insects, vertebrate and invertebrate animals, but are not found in plants. In this study, we performed an in silico screening of antimicrobial peptides, which led to discovery of a Brassica napus gene encoding a novel PR-AMP. This gene encodes a 35-amino acid peptide with 13 proline residues, designated BnPRP1. BnPRP1 has 40.5% identity with a known proline-rich antimicrobial peptide SP-B from the pig. BnPRP1 was artificially synthetized and cloned into the prokaryotic expression vector pET30a/His-EDDIE-GFP. Recombinant BnPRP1 was produced in Escherichia coli and has a predicted molecular mass of 3.8 kDa. Analysis of its activity demonstrated that BnPRP1 exhibited strong antimicrobial activity against Gram-positive bacterium, Gram-negative bacterium, yeast and also had strong antifungal activity against several pathogenic fungi, such as Sclerotinia sclerotiorum, Mucor sp., Magnaporthe oryzae and Botrytis cinerea. Circular dichroism (CD revealed the main secondary structure of BnPRP1 was the random coil. BnPRP1 gene expression detected by qRT-PCR is responsive to pathogen inoculation. At 48 hours after S. sclerotiorum inoculation, the expression of BnPRP1 increased significantly in the susceptible lines while slight decrease occurred in resistant lines. These suggested that BnPRP1 might play a role in the plant defense response against S. sclerotiorum. BnPRP1 isolated from B. napus was the first PR-AMP member that was characterized in plants, and its homology sequences were found in some other Brassicaceae plants by the genome sequences analysis. Compared with the known PR-AMPs, BnPRP1 has the different primary sequences and antimicrobial activity. Above all, this study gives a chance to cast a new light on further understanding about the AMPs' mechanism

  10. 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].

  11. Antimicrobial peptides from the skin secretions of the South-East Asian frog Hylarana erythraea (Ranidae).

    Science.gov (United States)

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

    2010-04-01

    Peptidomic analysis of norepinephrine-stimulated skin secretions of the South-East Asian frog Hylarana erythraea (formerly Rana erythraea partim) has led to the identification of multiple peptides with antimicrobial activity. Structural characterization of the peptides demonstrated that they belong to the brevinin-1 (3), brevinin-2 (2), esculentin-2 (4), and temporin (1) families. The values in parentheses indicate the number of paralogs. In addition, a peptide (GVIKSVLKGVAKTVALG ML.NH(2)) was isolated that shows some structural similarity to the brevinin-2-related peptides (B2RP) previously isolated from North American frogs of the genus Lithobates. A synthetic replicate of the species B2RP showed broad-spectrum growth inhibitory activity against reference strains of Escherichia coli (MIC=12.5 microM), Staphylococcus aureus (MIC=12.5 microM) and Candida albicans (MIC=50 microM) and was active against multidrug-resistant clinical isolates of Acetinobacter baumannii (MIC in the range 6-12.5 microM). The hemolytic activity of the peptide was relatively low (LC(50)=280 microM). Phylogenetic analysis based upon the amino acid sequences of 47 brevinin-2 peptides from 17 Asian species belonging to the family Ranidae provides support for the placement of H. erythraea in the genus Hylarana.

  12. Prediction of binding free energy for adsorption of antimicrobial peptide lactoferricin B on a POPC membrane

    Science.gov (United States)

    Vivcharuk, Victor; Tomberli, Bruno; Tolokh, Igor S.; Gray, C. G.

    2008-03-01

    Molecular dynamics (MD) simulations are used to study the interaction of a zwitterionic palmitoyl-oleoyl-phosphatidylcholine (POPC) bilayer with the cationic antimicrobial peptide bovine lactoferricin (LFCinB) in a 100 mM NaCl solution at 310 K. The interaction of LFCinB with POPC is used as a model system for studying the details of membrane-peptide interactions, with the peptide selected because of its antimicrobial nature. Seventy-two 3 ns MD simulations, with six orientations of LFCinB at 12 different distances from a POPC membrane, are carried out to determine the potential of mean force (PMF) or free energy profile for the peptide as a function of the distance between LFCinB and the membrane surface. To calculate the PMF for this relatively large system a new variant of constrained MD and thermodynamic integration is developed. A simplified method for relating the PMF to the LFCinB-membrane binding free energy is described and used to predict a free energy of adsorption (or binding) of -1.05±0.39kcal/mol , and corresponding maximum binding force of about 20 pN, for LFCinB-POPC. The contributions of the ions-LFCinB and the water-LFCinB interactions to the PMF are discussed. The method developed will be a useful starting point for future work simulating peptides interacting with charged membranes and interactions involved in the penetration of membranes, features necessary to understand in order to rationally design peptides as potential alternatives to traditional antibiotics.

  13. 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

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

    Science.gov (United States)

    Schulze, Martin; Junkes, Christof; Mueller, Peter; Speck, Stephanie; Ruediger, Karin; Dathe, Margitta; Mueller, Karin

    2014-01-01

    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.

  15. 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.

  16. Antimicrobial peptide incorporated poly(2-hydroxyethyl methacrylate) hydrogels for the prevention of Staphylococcus epidermidis-associated biomaterial infections.

    Science.gov (United States)

    Laverty, Garry; Gorman, Sean P; Gilmore, Brendan F

    2012-07-01

    The effectiveness of the antimicrobial peptide maximin-4, the ultrashort peptide H-Orn-Orn-Trp-Trp-NH(2), and the lipopeptide C(12)-Orn-Orn-Trp-Trp-NH(2) in preventing adherence of pathogens to a candidate biomaterial were tested utilizing both matrix- and immersion-loaded poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogels. Antiadherent properties correlated to both the concentration released and the relative antimicrobial concentrations of each compound against Staphylococcus epidermidis ATCC 35984, at each time point. Immersion-loaded samples containing C(12)-Orn-Orn-Trp-Trp-NH(2) exhibited the lowest adherence profile for all peptides studied over 1, 4, and 24 h. The results outlined in this article show that antimicrobial peptides have the potential to serve as an important weapon against biomaterial associated infections.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Julio Valdivia-Silva

    2015-06-01

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

  19. Two novel non-cationic defensin-like antimicrobial peptides from haemolymph of the female tick, Amblyomma hebraeum.

    Science.gov (United States)

    Lai, Ren; Lomas, Lee O; Jonczy, Jan; Turner, Philip C; Rees, Huw H

    2004-01-01

    Two non-cationic defensin-like antimicrobial peptides, named Amblyomma defensin peptide 1 and Amblyomma defensin peptide 2, were identified from the hard tick, Amblyomma hebraeum, by a combination of suppression subtractive hybridization for differentially expressed genes and proteomics. cDNA clones encoding each of these two defensin-like antimicrobial peptides were isolated from the differentially expressed cDNA library of the tick synganglia (central nervous system). The preproproteins deduced from the cDNA sequences each have 92 amino acid residues. Amblyomma defensin peptide 2 was purified from the haemolymph of fed female ticks. The purified peptide displayed antibacterial activity against Gram-negative and Gram-positive bacteria. Amblyomma defensin peptide 1 was further identified by protein chip capture combined with SELDI-TOF (surface-enhanced laser desorption/ionization-time-of-flight) MS. By screening for differentially expressed proteins, it was found that the expression of Amblyomma defensin peptide 1 was upregulated during 4 days post-feeding. Our findings firstly provide two defensin-like antimicrobial peptides that are particularly novel in being anionic, together with corresponding cDNA sequences, in hard ticks, and prove that the combination of suppression subtractive hybridization and protein profiling is a powerful method to study differentially expressed proteins, especially for organisms without available genome sequence information. PMID:14705963

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

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    Mauricio Arias

    2014-11-01

    Full Text Available Antimicrobial peptides (AMPs constitute promising candidates for the development of new antibiotics. Among the ever-expanding family of AMPs, tritrpticin has strong antimicrobial activity against a broad range of pathogens. This 13-residue peptide has an unusual amino acid sequence that is almost symmetrical and features three central Trp residues with two Arg residues near each end of the peptide. In this work, the role of the three sequential Trp residues in tritrpticin was studied in a systematic fashion by making a series of synthetic peptides with single-, double- and triple-Trp substitutions to Tyr or Ala. 1H NMR and fluorescence spectroscopy demonstrated the ability of all of the tritrpticin-analog peptides to interact with negatively-charged membranes. Consequently, most tritrpticin analogs exhibited the ability to permeabilize synthetic ePC:ePG (egg-yolk phosphatidylcholine (ePC, egg-yolk phosphatidylglycerol (ePG vesicles and live Escherichia coli bacteria. The membrane perturbation characteristics were highly dependent on the location of the Trp residue substitution, with Trp6 being the most important residue and Trp8 the least. The membrane permeabilization activity of the peptides in synthetic and biological membranes was directly correlated with the antimicrobial potency of the peptides against E. coli. These results contribute to the understanding of the role of each of the three Trp residues to the antimicrobial activity of tritrpticin.

  1. 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.

  2. Adsorption mechanism of an antimicrobial peptide on carbonaceous surfaces: A molecular dynamics study

    Science.gov (United States)

    Roccatano, Danilo; Sarukhanyan, Edita; Zangi, Ronen

    2017-02-01

    Peptides are versatile molecules with applications spanning from biotechnology to nanomedicine. They exhibit a good capability to unbundle carbon nanotubes (CNT) by improving their solubility in water. Furthermore, they are a powerful drug delivery system since they can easily be uptaken by living cells, and their high surface-to-volume ratio facilitates the adsorption of molecules of different natures. Therefore, understanding the interaction mechanism between peptides and CNT is important for designing novel therapeutical agents. In this paper, the mechanisms of the adsorption of antimicrobial peptide Cecropin A-Magainin 2 (CA-MA) on a graphene nanosheet (GNS) and on an ultra-short single-walled CNT are characterized using molecular dynamics simulations. The results show that the peptide coats both GNS and CNT surfaces through preferential contacts with aromatic side chains. The peptide packs compactly on the carbon surfaces where the polar and functionalizable Lys side chains protrude into the bulk solvent. It is shown that the adsorption is strongly correlated to the loss of the peptide helical structure. In the case of the CNT, the outer surface is significantly more accessible for adsorption. Nevertheless when the outer surface is already covered by other peptides, a spontaneous diffusion, via the amidated C-terminus into the interior of the CNT, was observed within 150 ns of simulation time. We found that this spontaneous insertion into the CNT interior can be controlled by the polarity of the entrance rim. For the positively charged CA-MA peptide studied, hydrogenated and fluorinated rims, respectively, hinder and promote the insertion.

  3. Adsorption mechanism of an antimicrobial peptide on carbonaceous surfaces: A molecular dynamics study.

    Science.gov (United States)

    Roccatano, Danilo; Sarukhanyan, Edita; Zangi, Ronen

    2017-02-21

    Peptides are versatile molecules with applications spanning from biotechnology to nanomedicine. They exhibit a good capability to unbundle carbon nanotubes (CNT) by improving their solubility in water. Furthermore, they are a powerful drug delivery system since they can easily be uptaken by living cells, and their high surface-to-volume ratio facilitates the adsorption of molecules of different natures. Therefore, understanding the interaction mechanism between peptides and CNT is important for designing novel therapeutical agents. In this paper, the mechanisms of the adsorption of antimicrobial peptide Cecropin A-Magainin 2 (CA-MA) on a graphene nanosheet (GNS) and on an ultra-short single-walled CNT are characterized using molecular dynamics simulations. The results show that the peptide coats both GNS and CNT surfaces through preferential contacts with aromatic side chains. The peptide packs compactly on the carbon surfaces where the polar and functionalizable Lys side chains protrude into the bulk solvent. It is shown that the adsorption is strongly correlated to the loss of the peptide helical structure. In the case of the CNT, the outer surface is significantly more accessible for adsorption. Nevertheless when the outer surface is already covered by other peptides, a spontaneous diffusion, via the amidated C-terminus into the interior of the CNT, was observed within 150 ns of simulation time. We found that this spontaneous insertion into the CNT interior can be controlled by the polarity of the entrance rim. For the positively charged CA-MA peptide studied, hydrogenated and fluorinated rims, respectively, hinder and promote the insertion.

  4. Influence of Amphibian Antimicrobial Peptides and Short Lipopeptides on Bacterial Biofilms Formed on Contact Lenses

    Directory of Open Access Journals (Sweden)

    Magdalena Maciejewska

    2016-10-01

    Full Text Available The widespread use of contact lenses is associated with several complications, including ocular biofilm-related infections. They are very difficult to manage with standard antimicrobial therapies, because bacterial growth in a biofilm is associated with an increased antibiotic resistance. The principal aim of this study was to evaluate the efficacy of antimicrobial peptides (AMPs in eradication of bacterial biofilms formed on commercially available contact lenses. AMPs were synthesized according to Fmoc/tBu chemistry using the solid-phase method. Minimum inhibitory concentration (MIC and minimum biofilm eradication concentration (MBEC of the compounds were determined. Anti-biofilm activity of the antimicrobial peptides determined at different temperatures (25 °C and 37 °C were compared with the effectiveness of commercially available contact lens solutions. All of the tested compounds exhibited stronger anti-biofilm properties as compared to those of the tested lens solutions. The strongest activity of AMPs was noticed against Gram-positive strains at a temperature of 25 °C. Conclusions: The results of our experiments encourage us toward further studies on AMPs and their potential application in the prophylaxis of contact lens-related eye infections.

  5. 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.

  6. New perspectives for natural antimicrobial peptides: application as antinflammatory drugs in a murine model

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    Capparelli Rosanna

    2012-11-01

    Full Text Available Abstract Background Antimicrobial peptides (AMPs are an ancient group of defense molecules. AMPs are widely distributed in nature (being present in mammals, birds, amphibians, insects, plants, and microorganisms. They display bactericidal as well as immunomodulatory properties. The aim of this study was to investigate the antimicrobial and anti-inflammatory activities of a combination of two AMPs (temporin B and the royal jellein I against Staphylococcus epidermidis. Results The temporin B (TB-KK and the royal jelleins I, II, III chemically modified at the C terminal (RJI-C, RJII-C, RJIII-C, were tested for their activity against 10 different Staphylococcus epidermidis strains, alone and in combination. Of the three royal jelleins, RJI-C showed the highest activity. Moreover, the combination of RJI-C and TB-KK (MIX displayed synergistic activity. In vitro, the MIX displayed low hemolytic activity, no NO2- production and the ability to curb the synthesis of the pro-inflammatory cytokines TNF-α and IFN-γ to the same extent as acetylsalicylic acid. In vivo, the MIX sterilized mice infected with Staphylococcus epidermidis in eleven days and inhibited the expression of genes encoding the prostaglandin-endoperoxide synthase 2 (COX-2 and CD64, two important parameters of inflammation. Conclusion The study shows that the MIX – a combination of two naturally occurring peptides - displays both antimicrobial and anti-inflammatory activities.

  7. Different mechanisms of action of antimicrobial peptides: insights from fluorescence spectroscopy experiments and molecular dynamics simulations.

    Science.gov (United States)

    Bocchinfuso, Gianfranco; Palleschi, Antonio; Orioni, Barbara; Grande, Giacinto; Formaggio, Fernando; Toniolo, Claudio; Park, Yoonkyung; Hahm, Kyung-Soo; Stella, Lorenzo

    2009-09-01

    Most antimicrobial peptides exert their activity by interacting with bacterial membranes, thus perturbing their permeability. They are investigated as a possible solution to the insurgence of bacteria resistant to the presently available antibiotic drugs. However, several different models have been proposed for their mechanism of membrane perturbation, and the molecular details of this process are still debated. Here, we compare fluorescence spectroscopy experiments and molecular dynamics (MD) simulations regarding the association with lipid bilayers and lipid perturbation for two different amphiphilic helical antimicrobial peptides, PMAP-23 and trichogin GA IV. PMAP-23, a cationic peptide member of the cathelicidin family, is considered to induce membrane permeability according to the Shai-Matsuzaki-Huang "carpet" model, while trichogin GA IV is a neutral peptide, member of the peptaibol family. Although several lines of evidence suggest a "barrel-stave" mechanism of pore formation for the latter peptide, its length is only half the normal thickness of a lipid bilayer. Both fluorescence spectroscopy experiments and MD simulations indicated that PMAP-23 associates with membranes close to their surface and parallel to it, and in this arrangement it causes a severe perturbation to the bilayer, both regarding its surface tension and lipid order. By contrast, trichogin GA IV can undergo a transition from a surface-bound state to a transmembrane orientation. In the first arrangement, it does not cause any strong membrane perturbation, while in the second orientation it might be able to span the bilayer from one side to the other, despite its relatively short length, by causing a significant thinning of the membrane.

  8. Recombinant expression and solution structure of antimicrobial peptide aurelin from jellyfish Aurelia aurita.

    Science.gov (United States)

    Shenkarev, Zakhar O; Panteleev, Pavel V; Balandin, Sergey V; Gizatullina, Albina K; Altukhov, Dmitry A; Finkina, Ekaterina I; Kokryakov, Vladimir N; Arseniev, Alexander S; Ovchinnikova, Tatiana V

    2012-12-07

    Aurelin is a 40-residue cationic antimicrobial peptide isolated from the mezoglea of a scyphoid jellyfish Aurelia aurita. Aurelin and its (15)N-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 3(10)-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.

  9. Activity of antimicrobial peptide mimetics in the oral cavity: I. Activity against biofilms of Candida albicans.

    Science.gov (United States)

    Hua, J; Yamarthy, R; Felsenstein, S; Scott, R W; Markowitz, K; Diamond, G

    2010-12-01

    Naturally occurring antimicrobial peptides hold promise as therapeutic agents against oral pathogens such as Candida albicans but numerous difficulties have slowed their development. Synthetic, non-peptidic analogs that mimic the properties of these peptides have many advantages and exhibit potent, selective antimicrobial activity. Several series of mimetics (with molecular weight oral Candida strains as a proof-of-principle for their antifungal properties. One phenylalkyne and several arylamide compounds with reduced mammalian cytotoxicities were found to be active against C. albicans. These compounds demonstrated rapid fungicidal activity in liquid culture even in the presence of saliva, and demonstrated synergy with standard antifungal agents. When assayed against biofilms grown on denture acrylic, the compounds exhibited potent fungicidal activity as measured by metabolic and fluorescent viability assays. Repeated passages in sub-minimum inhibitory concentration levels did not lead to resistant Candida, in contrast to fluconazole. Our results demonstrate the proof-of principle for the use of these compounds as anti-Candida agents, and their further testing is warranted as novel anti-Candida therapies.

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

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    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.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  13. Non-Membrane Permeabilizing Modes of Action of Antimicrobial Peptides on Bacteria.

    Science.gov (United States)

    Scocchi, Marco; Mardirossian, Mario; Runti, Giulia; Benincasa, Monica

    2016-01-01

    Antimicrobial peptides (AMPs) are a large class of innate immunity effectors with a remarkable capacity to inactivate microorganisms. Their ability to kill bacteria by membranolytic effects has been well established. However, a lot of evidence points to alternative, non-lytic modes of action for a number of AMPs, which operate through interactions with specific molecular targets. It has been reported that non-membrane-permeabilizing AMPs can bind to and inhibit DNA, RNA or protein synthesis processes, inactivate essential intracellular enzymes, or affect membrane septum formation and cell wall synthesis. This minireview summarizes recent findings on these alternative, non-lytic modes of antimicrobial action with an emphasis to the experimental approaches used to clarify each step of their intracellular action, i.e. the cell penetration mechanism, intracellular localization and molecular mechanisms of antibacterial action. Despite the fact that such data exists for a large number of peptides, our analysis indicates that only for a small number of AMPs sufficient data have been collected to support a mode of action with an authentic and substantial contribution by intracellular targeting. In most cases, peptides with non-lytic features have not been thoroughly analyzed, or only a single aspect of their mode of action has been taken into consideration and therefore their mechanism of action can only be hypothesized. A more detailed knowledge of this class of AMPs would be important in the design of novel antibacterial agents against unexploited targets, endowed with the capacity to penetrate into pathogen cells and kill them from within.

  14. Defensive remodeling: How bacterial surface properties and biofilm formation promote resistance to antimicrobial peptides.

    Science.gov (United States)

    Nuri, Reut; Shprung, Tal; Shai, Yechiel

    2015-11-01

    Multidrug resistance bacteria are a major concern worldwide. These pathogens cannot be treated with conventional antibiotics and thus alternative therapeutic agents are needed. Antimicrobial peptides (AMPs) are considered to be good candidates for this purpose. Most AMPs are short and positively charged amphipathic peptides, which are found in all known forms of life. AMPs are known to kill bacteria by binding to the negatively charged bacterial surface, and in most cases cause membrane disruption. Resistance toward AMPs can be developed, by modification of bacterial surface molecules, secretion of protective material and up-regulation or elimination of specific proteins. Because of the general mechanisms of attachment and action of AMPs, bacterial resistance to AMPs often involves biophysical and biochemical changes such as surface rigidity, cell wall thickness, surface charge, as well as membrane and cell wall modification. Here we focus on the biophysical, surface and surrounding changes that bacteria undergo in acquiring resistance to AMPs. In addition we discuss the question of whether bacterial resistance to administered AMPs might compromise our innate immunity to endogenous AMPs. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.

  15. Conjugation with Acridines Turns Nuclear Localization Sequence into Highly Active Antimicrobial Peptide

    Directory of Open Access Journals (Sweden)

    Zhang Wei

    2015-12-01

    Full Text Available The emergence of multidrug-resistant bacteria creates an urgent need for alternative antibiotics with new mechanisms of action. In this study, we synthesized a novel type of antimicrobial agent, Acr3-NLS, by conjugating hydrophobic acridines to the N-terminus of a nuclear localization sequence (NLS, a short cationic peptide. To further improve the antimicrobial activity of our agent, dimeric (Acr3-NLS2 was simultaneously synthesized by joining two monomeric Acr3-NLS together via a disulfide linker. Our results show that Acr3-NLS and especially (Acr3-NLS2 display significant antimicrobial activity against gram-negative and gram-positive bacteria compared to that of the NLS. Subsequently, the results derived from the study on the mechanism of action demonstrate that Acr3-NLS and (Acr3-NLS2 can kill bacteria by membrane disruption and DNA binding. The double targets–cell membrane and intracellular DNA–will reduce the risk of bacteria developing resistance to Acr3-NLS and (Acr3-NLS2. Overall, this study provides a novel strategy to design highly effective antimicrobial agents with a dual mode of action for infection treatment.

  16. Effect of Antimicrobial Peptide KSL-W on Human Gingival Tissue and C. albicans Growth, Transition and Secreted Aspartyl Proteinase (SAPS) 2, 4, 5 and 6 Expressions

    Science.gov (United States)

    2014-04-01

    fungi resistance , antimicrobial peptides, cationic peptides, chemical peptides, KSL-W. 3-ACCOMPLISHMENTS: There was no change as to the original...1 AWARD NUMBER: W81XWH-12-2-0025 TITLE: Effect of Antimicrobial Peptide KSL-W on Human Gingival Tissue and C. albicans Growth, Transition...of the Army position, policy or decision unless so designated by other documentation. REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188

  17. Induced bacterial cross-resistance toward host antimicrobial peptides: a worrying phenomenon

    Directory of Open Access Journals (Sweden)

    Osmel eFleitas

    2016-03-01

    Full Text Available 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 association with cross-resistance toward AMP effectors of the host innate immune system. In this context, the use of AMPs as a therapeutic option could be potentially hazardous, since bacteria could develop resistance toward our innate immune system. Here we review the findings of major studies that deal with the AMP cross-resistance phenomenon.

  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.

  19. Gene cloning and functional characterization of four novel antimicrobial-like peptides from scorpions of the family Vaejovidae.

    Science.gov (United States)

    Ramírez-Carreto, Santos; Quintero-Hernández, Verónica; Jiménez-Vargas, Juana María; Corzo, Gerardo; Possani, Lourival D; Becerril, Baltazar; Ortiz, Ernesto

    2012-04-01

    From the cDNA libraries made from the venom glands of two scorpions belonging to the Vaejovidae family, four different putative non disulfide-bridged antimicrobial peptides were identified: VmCT1 and VmCT2 from Vaejovis mexicanus smithi plus VsCT1 and VsCT2 from Vaejovis subcristatus. These short peptides (with only 13 amino acid residues each) share important amino acid sequence similarities among themselves and with other reported antimicrobial peptides, but their biological activities vary dramatically. This communication reports the cloning, chemical synthesis and characterization of these peptides. Two peptides, VmCT1 and VmCT2 showed broad-spectrum antibacterial activity with minimum inhibitory concentrations MICs in the range of 5-25 μM and 10-20 μM respectively, whereas their hemolytic activity at these concentrations was low. Structure-function relationships that might determine the differences in activities are discussed.

  20. Role of the Escherichia coli SbmA in the antimicrobial activity of proline-rich peptides.

    Science.gov (United States)

    Mattiuzzo, Maura; Bandiera, Antonella; Gennaro, Renato; Benincasa, Monica; Pacor, Sabrina; Antcheva, Nikolinka; Scocchi, Marco

    2007-10-01

    In contrast to many antimicrobial peptides, members of the proline-rich group of antimicrobial peptides inactivate Gram-negative bacteria by a non-lytic mechanism. Several lines of evidence indicate that they are internalized into bacteria and their activity mediated by interaction with unknown cellular components. With the aim of identifying such interactors, we selected mutagenized Escherichia coli clones resistant to the proline-rich Bac7(1-35) peptide and analysed genes responsible for conferring resistance, whose products may thus be involved in the peptide's mode of action. We isolated a number of genomic regions bearing such genes, and one in particular coding for SbmA, an inner membrane protein predicted to be part of an ABC transporter. An E. coli strain carrying a point mutation in sbmA, as well as other sbmA-null mutants, in fact showed resistance to several proline-rich peptides but not to representative membranolytic peptides. Use of fluorescently labelled Bac7(1-35) confirmed that resistance correlated with a decreased ability to internalize the peptide, suggesting that a bacterial protein, SbmA, is necessary for the transport of, and for susceptibility to, proline-rich antimicrobial peptides of eukaryotic origin.

  1. Nanovesicle encapsulation of antimicrobial peptide P34: physicochemical characterization and mode of action on Listeria monocytogenes

    Science.gov (United States)

    da Silva Malheiros, Patrícia; Sant'Anna, Voltaire; Micheletto, Yasmine Miguel Serafini; da Silveira, Nadya Pesce; Brandelli, Adriano

    2011-08-01

    Antimicrobial peptide P34, a substance showing antibacterial activity against pathogenic and food spoilage bacteria, was encapsulated in liposomes prepared from partially purified soybean phosphatidylcholine, and their physicochemical characteristics were evaluated. The antimicrobial activity was estimated by agar diffusion assay using Listeria monocytogenes ATCC 7644 as indicator strain. A concentration of 3,200 AU/mL of P34 was encapsulated in nanovesicles and stocked at 4 °C. No significant difference ( p > 0.05) in the biological activity of free and encapsulated P34 was observed through 24 days. Size and PDI of liposomes, investigated by light scattering analysis, were on average 150 nm and 0.22 respectively. Zeta potential was -27.42 mV. There was no significant change ( p > 0.05) in the physicochemical properties of liposomes during the time of evaluation. The liposomes presented closed spherical morphology as visualized by transmission electron microscopy (TEM). The mode of action of liposome-encapsulated P34 under L. monocytogenes cells was investigated by TEM. Liposomes appeared to adhere but not fuse with the bacterial cell wall, suggesting that the antimicrobial is released from nanovesicles to act against the microorganism. The effect of free and encapsulated P34 was tested against L. monocytogenes, showing that free bacteriocin inhibited the pathogen more quickly than the encapsulated P34. Liposomes prepared with low-cost lipid showed high encapsulation efficiency for a new antimicrobial peptide and were stable during storage. The mode of action against the pathogen L. monocytogenes was characterized.

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

    Science.gov (United States)

    Schnitt, Rebecca Ann

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

  3. Innate defense regulator peptide 1018 in wound healing and wound infection.

    Directory of Open Access Journals (Sweden)

    Lars Steinstraesser

    Full Text Available Innate defense regulators (IDRs are synthetic immunomodulatory versions of natural host defense peptides (HDP. IDRs mediate protection against bacterial challenge in the absence of direct antimicrobial activity, representing a novel approach to anti-infective and anti-inflammatory therapy. Previously, we reported that IDR-1018 selectively induced chemokine responses and suppressed pro-inflammatory responses. As there has been an increasing appreciation for the ability of HDPs to modulate complex immune processes, including wound healing, we characterized the wound healing activities of IDR-1018 in vitro. Further, we investigated the efficacy of IDR-1018 in diabetic and non-diabetic wound healing models. In all experiments, IDR-1018 was compared to the human HDP LL-37 and HDP-derived wound healing peptide HB-107. IDR-1018 was significantly less cytotoxic in vitro as compared to either LL-37 or HB-107. Furthermore, administration of IDR-1018 resulted in a dose-dependent increase in fibroblast cellular respiration. In vivo, IDR-1018 demonstrated significantly accelerated wound healing in S. aureus infected porcine and non-diabetic but not in diabetic murine wounds. However, no significant differences in bacterial colonization were observed. Our investigation demonstrates that in addition to previously reported immunomodulatory activities IDR-1018 promotes wound healing independent of direct antibacterial activity. Interestingly, these effects were not observed in diabetic wounds. It is anticipated that the wound healing activities of IDR-1018 can be attributed to modulation of host immune pathways that are suppressed in diabetic wounds and provide further evidence of the multiple immunomodulatory activities of IDR-1018.

  4. ANTISTAPHYBASE: database of antimicrobial peptides (AMPs) and essential oils (EOs) against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus.

    Science.gov (United States)

    Zouhir, Abdelmajid; Taieb, Malek; Lamine, Mohamed Ashraf; Cherif, Ammar; Jridi, Taoufik; Mahjoubi, Basma; Mbarek, Sarra; Fliss, Ismail; Nefzi, Adel; Sebei, Khaled; Ben Hamida, Jeannette

    2017-03-01

    Staphylococcus aureus and methicillin-resistant S. aureus are major pathogens. The antimicrobial peptides and essential oils (EOs) display narrow- or broad-spectrum activity against bacteria including these strains. A centralized resource, such as a database, designed specifically for anti-S. aureus/anti-methicillin-resistant S. aureus antimicrobial peptides and EOs is therefore needed to facilitate the comprehensive investigation of their structure/activity associations and combinations. The database ANTISTAPHYBASE is created to facilitate access to important information on antimicrobial peptides and essential peptides against methicillin-resistant S. aureus and S. aureus. At the moment, the database contains 596 sequences of antimicrobial peptides produced by diverse organisms and 287 essential oil records. It permits a quick and easy search of peptides based on their activity as well as their general, physicochemical properties and literature data. These data are very useful to perform further bioinformatic or chemometric analysis and would certainly be useful for the development of new drugs for medical use. The ANTISTAPHYBASE database is freely available at: https://www.antistaphybase.com/ .

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

    DEFF Research Database (Denmark)

    Guo, Chunxiao; Rosoha, Elena; Lowry, Malcolm B;

    2013-01-01

    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 (CAMP) and 1,25-dihydroxyvitamin D(3) 24-hydroxylase (CYP24A1) - in human monocytic cell line U937, colon...... cancer cell line HT-29 and keratinocyte cell line HaCaT. We demonstrated that PUFAs failed to induce CAMP or CYP24A1 mRNA expression in all three cell lines, but curcumin up-regulated CAMP mRNA and protein levels in U937 cells. Curcumin treatment induced CAMP promoter activity from a luciferase reporter...

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

    Science.gov (United States)

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

    2014-09-01

    A single step immobilization-polymerization strategy of a highly active antimicrobial peptide into a soft hydrogel network on a poly(ethylene terephthalate) surface using thiol-ene chemistry is described. The bactericidal hydrogel was molecularly characterized via Coomassie and Lowry assay protein staining agents as well as by X-ray photoelectron spectroscopy. The bactericidal activity was established against Staphylococcus aureus and Staphylococcus epidermidis, two bacterial strains commonly associated with biomaterial infections. To gain further insight into the biological stability, the hydrogels were incubated with human serum prior to activity testing without loss of activity. These studies revealed a promising bactericidal hydrogel with good stability under physiological conditions.

  7. Identification of multiple peptides with antioxidant and antimicrobial activities from skin and its secretions of Hylarana taipehensis, Amolops lifanensis, and Amolops granulosus.

    Science.gov (United States)

    Guo, Chao; Hu, Yuhong; Li, Jing; Liu, Yuliang; Li, Sihan; Yan, Keqiang; Wang, Xiao; Liu, Jingze; Wang, Hui

    2014-10-01

    Amphibian skin and its secretions contain many kinds of peptides with different bioactivities. In this study, a large number of peptides including antioxidant and antimicrobial peptides were identified from three East Asian frog species Hylarana taipehensis, Amolops lifanensis, and Amolops granulosus. The majority of these peptides were antimicrobial peptides, while eight antioxidant peptides were identified, which included two novel peptides taipehensin-1TP1 (TLIWEFYHQILDEYNKENKG) and taipehensin-2TP1 (CLMARPNYRCKIFKQC). These antioxidant peptides exhibited the ability to scavenge ABTS and/or DPPH free radicals. Moreover, six out of eight antioxidant peptides temporin-TP1, brevinin-1TP1, brevinin-1TP2, brevinin-1TP3, brevinin-1LF1, and palustrin-2GN1 also showed antimicrobial activity.

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

    DEFF Research Database (Denmark)

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

    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...

  9. Impact of the antimicrobial peptide Novicidin on membrane structure and integrity

    DEFF Research Database (Denmark)

    Nielsen, Søren B; Otzen, Daniel Erik

    2010-01-01

    We have studied the impact of an 18-residue cationic antimicrobial peptide Novicidin (Nc) on the structure and integrity of partially anionic lipid membranes using oriented circular dichroism (OCD), quartz crystal microbalance with dissipation (QCM-D), dual polarization interferometry (DPI...... fluorescence spectroscopy and by loss of lipid alignment in DPI analysis. Laurdan generalized polarity shows a decrease in water accessibility or mobility in the hydrophobic/hydrophilic interface of the lipid membrane, consistent with rearrangement of lipid packing. QCM-D studies on the interaction of Nc...... with lipid membranes emphasize the importance of including the dissipation factor in data analysis, revealing formation of a highly hydrated film after exposure to 3muMNc. Our findings suggest a carpet mechanism of membrane disruption in which peptide binding first induces leakage at a critical surface...

  10. 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

    intracellularly in Calu-3 epithelial cells and in THP-1 cells, whereas A549 cells did not show significant uptake of nanoparticles. Overall, encapsulation of plectasin into PLGA-based nanoparticles appears to be a viable strategy to improve the efficacy of plectasin against infections in epithelial tissues....... epithelial cells might thus be a promising approach to combat such infections. In this work, plectasin, which is a cationic AMP of the defensin class, was encapsulated into poly(lactic-co-glycolic acid) (PLGA) nanoparticles using the double emulsion solvent evaporation method. The nanoparticles displayed...... 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...

  11. Oligomeric structure of a cathelicidin antimicrobial peptide in dodecylphosphocholine micelle determined by NMR spectroscopy.

    Science.gov (United States)

    Saravanan, Rathi; Bhattacharjya, Surajit

    2011-01-01

    The broad spectrum of antibacterial activities of host defense cationic antimicrobial peptides (AMPs) arises from their ability to perturb membrane integrity of the microbes. The mechanisms are often thought to require assembly of AMPs on the membrane surface to form pores. However, three dimensional structures in the oligomeric form of AMPs in the context of lipid membranes are largely limited. Here, we demonstrate that a 22-residue antimicrobial peptide, termed VK22, derived from fowlicidin-1, a cathelicidin family of AMP from chicken oligomerizes into a predominantly tetrameric state in zwitterionic dodecylphosphocholine (DPC) micelles. An ensemble of NMR structures of VK22 determined in 200mM perdeuterated DPC, from 755 NOE constrains including 19 inter-helical NOEs, had revealed an assembly of four helices arranged in anti-parallel fashion. Hydrogen bonds, C(α)H-O=C types, and van der Waals interactions among the helical sub-units appear to be involved in the stabilization of the quaternary structures. The central region of the barrel shaped tetrameric bundle is non-polar with clusters of aromatic residues, whereas all the cationic residues are positioned at the termini. Paramagnetic spin labeled NMR experiments indicated that the tetrameric structure is embedded into micelles such that the non-polar region located inside the lipid acyl chains. Structure and micelle localization of a monomeric version, obtained from substitution of two Tyr residues with Ala, of the peptide is also compared. The mutated peptide VK22AA has been found be localized at the surface of the micelles. The tetrameric structure of VK22 delineates a small water pore that can be larger in the higher order oligomers. As these results provide structural insights, at atomic resolution, into the oligomeric states of a helical AMP in lipid environment, the structural details may be further utilized for the design of novel self-assembled membrane protein mimics.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Corynebacterium glutamicum exhibits a membrane-related response to a small ferrocene-conjugated antimicrobial peptide.

    Science.gov (United States)

    Fränzel, Benjamin; Frese, Christian; Penkova, Maya; Metzler-Nolte, Nils; Bandow, Julia E; Wolters, Dirk Andreas

    2010-11-01

    Multiresistant bacteria are becoming more and more widespread. It is therefore necessary to have new compound groups in hand, such as small cationic peptides, to cope with these challenges. In this work, we present a comprehensive approach by monitoring protein expression profiles in a gram-positive bacterium (Corynebacterium glutamicum) to investigate the cellular response to such a compound, a ferrocene-conjugated arginine- and tryptophan-rich pentapeptide. To achieve this, a proteomic outline was performed where the compound-treated sample was compared with an untreated control. This study comprises more than 900 protein identifications, including numerous integral membrane proteins, and among these 185 differential expressions. Surprisingly, unregulated catalase and no elevated H(2)O(2) levels demonstrate that no oxidative stress occurs after treatment with the iron-containing compound as a consequence of the potential Fenton reaction. A sufficient iron supply is evidenced by the iron-containing protein aconitase and SufB (the latter belongs to an iron-sulfur cluster assembly system) and decreased levels of ATP-binding-cassette-type cobalamin/Fe(3+) siderophore transporters. The organometallic peptide antibiotic targets the cell membrane, which is evident by decreased levels of various integral membrane proteins, such as peptide permeases and transporters, and an altered lipid composition. Conversion to a more rigid cell membrane seems to be a relevant protective strategy of C. glutamicum against the ferrocene-conjugated antimicrobial peptide compound.

  14. Evidence of an Antimicrobial Peptide Signature Encrypted in HECT E3 Ubiquitin Ligases

    Science.gov (United States)

    Candido-Ferreira, Ivan Lavander; Kronenberger, Thales; Sayegh, Raphael Santa Rosa; Batista, Isabel de Fátima Correia; da Silva Junior, Pedro Ismael

    2017-01-01

    The ubiquitin-proteasome pathway (UPP) is a hallmark of the eukaryotic cell. In jawed vertebrates, it has been co-opted by the adaptive immune system, where proteasomal degradation produces endogenous peptides for major histocompatibility complex class I antigen presentation. However, proteolytic products are also necessary for the phylogenetically widespread innate immune system, as they often play a role as host defense peptides (HDPs), pivotal effectors against pathogens. Here, we report the identification of the arachnid HDP oligoventin, which shares homology to a core member of the UPP, E3 ubiquitin ligases. Oligoventin has broad antimicrobial activity and shows strong synergy with lysozymes. Using computational and phylogenetic approaches, we show high conservation of the oligoventin signature in HECT E3s. In silico simulation of HECT E3s self-proteolysis provides evidence that HDPs can be generated by fine-tuned 26S proteasomal degradation, and therefore are consistent with the hypothesis that oligoventin is a cryptic peptide released by the proteolytic processing of an Nedd4 E3 precursor protein. Finally, we compare the production of HDPs and endogenous antigens from orthologous HECT E3s by proteasomal degradation as a means of analyzing the UPP coupling to metazoan immunity. Our results highlight the functional plasticity of the UPP in innate and adaptive immune systems as a possibly recurrent mechanism to generate functionally diverse peptides. PMID:28119686

  15. Enhanced membrane pore formation through high-affinity targeted antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Christopher J Arnusch

    Full Text Available Many cationic antimicrobial peptides (AMPs target the unique lipid composition of the prokaryotic cell membrane. However, the micromolar activities common for these peptides are considered weak in comparison to nisin, which follows a targeted, pore-forming mode of action. Here we show that AMPs can be modified with a high-affinity targeting module, which enables membrane permeabilization at low concentration. Magainin 2 and a truncated peptide analog were conjugated to vancomycin using click chemistry, and could be directed towards specific membrane embedded receptors both in model membrane systems and whole cells. Compared with untargeted vesicles, a gain in permeabilization efficacy of two orders of magnitude was reached with large unilamellar vesicles that included lipid II, the target of vancomycin. The truncated vancomycin-peptide conjugate showed an increased activity against vancomycin resistant Enterococci, whereas the full-length conjugate was more active against a targeted eukaryotic cell model: lipid II containing erythrocytes. This study highlights that AMPs can be made more selective and more potent against biological membranes that contain structures that can be targeted.

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

    Science.gov (United States)

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

    2012-11-01

    The impact of inserting hydrocarbon staples into short α-helical antimicrobial peptides lasioglossin III and melectin (antimicrobial peptides of wild bee venom) on their biological and biophysical properties has been examined. The stapling was achieved by ring-closing olefin metathesis, either between two S-2-(4'-pentenyl) alanine residues (S (5)) incorporated at i and i + 4 positions or between R-2-(7'-octenyl) alanine (R (8)) and S (5) incorporated at the i and i + 7 positions, respectively. We prepared several lasioglossin III and melectin analogs with a single staple inserted into different positions within the peptide chains as well as analogs with double staples. The stapled peptides exhibited a remarkable increase in hemolytic activity, while their antimicrobial activities decreased. Some single stapled peptides showed a higher resistance against proteolytic degradation than native ones, while the double stapled analogs were substantially more resistant. The CD spectra of the singly stapled peptides measured in water showed only a slightly better propensity to form α-helical structure when compared to native peptides, whereas the doubly stapled analogs exhibited dramatically enhanced α-helicity.

  17. Antimicrobial Peptides:Design and Application%抗菌肽的设计及其应用

    Institute of Scientific and Technical Information of China (English)

    陈宇婷; 王长海; 严秀文; 黎军胜

    2013-01-01

    抗菌肽(AMP)是生物体内先天免疫系统的一个组成部分,保护机体免受致病微生物的入侵.抗菌肽具有很强的广谱抗菌活性,可抑制革兰氏阳性菌、革兰氏阴性菌、真菌和病毒的生长.为克服微生物对抗生素耐药性的问题,目前阳离子抗菌肽已被考虑作为抗生素的潜在替代品.本文将阐述抗菌肽的作用机理、选择性抗菌肽的设计及其应用.%Antimicrobial peptide(AMP) is an integral part of the innate immune system in living organisms that protect hosts from invading pathogenic microorganism.AMPs have strong antimicrobial activity against a wide-range of species,including gram-positive and gram-negative bacteria,fungi,and viruses.In order to overcome the problem of resistance,cationic antimicrobial peptides are currently being considered as a potential alternative for antibiotics.This review focuses on the mechanism and application of the antimicrobial peptides and discusses the design of molecular targeted antimicrobial peptides.

  18. Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: II. Intestinal morphology and function.

    Science.gov (United States)

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

    2013-10-01

    Deoxynivalenol (DON) affects animal and human health and targets the gastrointestinal tract. The objective of this study was to evaluate the ability of composite antimicrobial peptides (CAP) to repair intestinal injury in piglets challenged with DON. A total of 28 piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% composite antimicrobial peptide (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 mg/kg DON + 0.4% CAP (DON + CAP). After an adaptation period of 7 d, blood samples were collected on d 15 and 30 after the initiation of treatment for determinations of the concentrations of D-lactate and diamine oxidase. At the end of the study, all piglets were slaughtered to obtain small intestines for the determination of intestinal morphology, epithelial cell proliferation, and protein expression in the mammalian target of rapamycin (mTOR) signaling pathway. The results showed that DON increased serum concentrations of D-lactate and diamine oxidase, and these values in the CAP and DON + CAP treatments were less than those in the NC and DON treatments, respectively (P morphology and promoted intestinal epithelial cell proliferation and protein synthesis, indicating that CAP may repair the intestinal injury induced by DON.

  19. Biofunctionalization of microgroove titanium surfaces with an antimicrobial peptide to enhance their bactericidal activity and cytocompatibility.

    Science.gov (United States)

    Zhou, Lin; Lai, Yingzhen; Huang, Wenxiu; Huang, Sijia; Xu, Zhiqiang; Chen, Jiang; Wu, Dong

    2015-04-01

    A firm peri-implant soft tissue seal is important for the long-term survival of dental implants, which demands the properties of antibacterial and cytocompatibility of the implant surfaces. In this study, GL13K, a cationic antimicrobial peptide, was immobilized onto microgroove surfaces which were 60 μm in width and 10 μm in depth, and the modified surfaces improved both the properties of antibacterial and cytocompatibility. The method of silanization was used to immobilize the antimicrobial peptide GL13K, which was confirmed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle measurement. Then the mechanical stability of the coatings was confirmed by ultrasonication. In vitro antibacterial tests confirmed bactericidal activity against Porphyromonas gingivalis without inhibiting its adhesion. In vitro cytocompatibility tests also confirmed that adhesion at later phase and proliferation of HGFs were greater (P<0.01) on the GL13K-modified microgroove surfaces than on the non-treated microgroove surfaces, and both of them were greater than on the smooth surfaces. The phenomenon of the contact guidance, which is cell growth aligned along the microgrooves, was maintained. Overall, this study developed a promising bi-functional surface that combined the physical and chemical properties to promote cytocompatibility and antibacterial activity simultaneously.

  20. Molecular characterization of Lingual antimicrobial peptide in the female reproductive tract of Buffalo

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    Dhanya Joseph and Tukaram More

    2011-06-01

    Full Text Available Bubalus bubalis (Ruminantia: Bovidae, Bovinae is an economically important animal of many Asian countries, making significant contribution to milk and meat production. Sub clinical infection of the reproductive tract is one of the important causes for reduced reproductive efficiency in dairy herd of buffaloes. Antimicrobial peptides are component of innate immune system which helps in augmenting the resistance to infection at epithelial surfaces e.g reproductive tract epithelium. In this study we have identified a ß-defensin called Lingual Antimicrobial Peptide (LAP in buffalo reproductive tract. Interestingly the gene was 100 % identical to the LAP isolated from the tongue epithelium of Bos taurus. The 195 bp cDNA of LAP codes for 64 amino acids and of which 50% are cationic amino acids. Phylogenetic studies indicate that LAP of reproductive epithelium of buffalo is different from other beta defensins isolated from the various tissues of same species, but all beta defensin were found to have the same progenitor gene. It is concluded that buffalo reproductive tract epithelium lining contains LAP. [Vet. World 2011; 4(3.000: 120-123

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

    Science.gov (United States)

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

    2015-12-01

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

  2. Vitamin D analogs differentially control antimicrobial peptide/"alarmin" expression in psoriasis.

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    Mark Peric

    Full Text Available Antimicrobial peptides (AMPs are strongly expressed in lesional skin in psoriasis and play an important role as proinflammatory "alarmins" in this chronic skin disease. Vitamin D analogs like calcipotriol have antipsoriatic effects and might mediate this effect by changing AMP expression. In this study, keratinocytes in lesional psoriatic plaques showed decreased expression of the AMPs beta-defensin (HBD 2 and HBD3 after topical treatment with calcipotriol. At the same time, calcipotriol normalized the proinflammatory cytokine milieu and decreased interleukin (IL-17A, IL-17F and IL-8 transcript abundance in lesional psoriatic skin. In contrast, cathelicidin antimicrobial peptide expression was increased by calcipotriol while psoriasin expression remained unchanged. In cultured human epidermal keratinocytes the effect of different vitamin D analogs on the expression of AMPs was further analyzed. All vitamin D analogs tested blocked IL-17A induced HBD2 expression by increasing IkappaB-alpha protein and inhibition of NF-kappaB signaling. At the same time vitamin D analogs induced cathelicidin through activation of the vitamin D receptor and MEK/ERK signaling. These studies suggest that vitamin D analogs differentially alter AMP expression in lesional psoriatic skin and cultured keratinocytes. Balancing AMP "alarmin" expression might be a novel goal in treatment of chronic inflammatory skin diseases.

  3. Expression of Antimicrobial Peptide Dybowskin-2CAMa in Pichia pastoris and Characterization of its Antibacterial Activity

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    Lili Jin

    2013-08-01

    Full Text Available In this study we used a yeast expression system to express a new antimicrobial peptide dybowskin-2CAMa from the skin cDNA library of Rana amurenisis. The entire coding region of the dybowskin-2CAMa was cloned into the plasmid pPICZ&alpha-A and then transformed into competent P. pastoris X33. The expressed dybowskin-2CAMa was purified from the culture supernatant by Sephadex G-25 and YMC*GEL ODS-A chromatography followed by C18 reverse phased HPLC. The purified peptide exhibited a single band of about 2 kDa when resolved by Tricine-SDS-PAGE. Its exact molecular weight was 2456.46 Da which was consistent with the value predicted from its deduced amino acid sequence. Antimicrobial activity assay showed that the recombinant dybowskin-2CAMa could inhibit the growth of a broad spectrum of bacteria, while displaying very low level of hemolytic activity (&le4% relative to Triton X-100, even at concentration of up to 500 &mug/mL.

  4. Effects of microplusin, a copper-chelating antimicrobial peptide, against Cryptococcus neoformans.

    Science.gov (United States)

    Silva, Fernanda D; Rossi, Diego C P; Martinez, Luis R; Frases, Susana; Fonseca, Fernanda L; Campos, Claudia Barbosa L; Rodrigues, Marcio L; Nosanchuk, Joshua D; Daffre, Sirlei

    2011-11-01

    Microplusin is an antimicrobial peptide isolated from the cattle tick Rhipicephalus (Boophilus) microplus. Its copper-chelating ability is putatively responsible for its bacteriostatic activity against Micrococcus luteus as microplusin inhibits respiration in this species, which is a copper-dependent process. Microplusin is also active against Cryptococcus neoformans (MIC(50) = 0.09 μM), the etiologic agent of cryptococcosis. Here, we show that microplusin is fungistatic to C. neoformans and this inhibitory effect is abrogated by copper supplementation. Notably, microplusin drastically altered the respiratory profile of C. neoformans. In addition, microplusin affects important virulence factors of this fungus. We observed that microplusin completely inhibited fungal melanization, and this effect correlates with the inhibition of the related enzyme laccase. Also, microplusin significantly inhibited the capsule size of C. neoformans. Our studies reveal, for the first time, a copper-chelating antimicrobial peptide that inhibits respiration and growth of C. neoformans and modifies two major virulence factors: melanization and formation of a polysaccharide capsule. These features suggest that microplusin, or other copper-chelation approaches, may be a promising therapeutic for cryptococcosis.

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

    Science.gov (United States)

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

    2011-01-01

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

  6. Liquid-crystalline ordering of antimicrobial peptide-DNA complexes controls TLR9 activation

    Science.gov (United States)

    Schmidt, Nathan W.; Jin, Fan; Lande, Roberto; Curk, Tine; Xian, Wujing; Lee, Calvin; Frasca, Loredana; Frenkel, Daan; Dobnikar, Jure; Gilliet, Michel; Wong, Gerard C. L.

    2015-07-01

    Double-stranded DNA (dsDNA) can trigger the production of type I interferon (IFN) in plasmacytoid dendritic cells (pDCs) by binding to endosomal Toll-like receptor-9 (TLR9; refs , , , , ). It is also known that the formation of DNA-antimicrobial peptide complexes can lead to autoimmune diseases via amplification of pDC activation. Here, by combining X-ray scattering, computer simulations, microscopy and measurements of pDC IFN production, we demonstrate that a broad range of antimicrobial peptides and other cationic molecules cause similar effects, and elucidate the criteria for amplification. TLR9 activation depends on both the inter-DNA spacing and the multiplicity of parallel DNA ligands in the self-assembled liquid-crystalline complex. Complexes with a grill-like arrangement of DNA at the optimum spacing can interlock with multiple TLR9 like a zipper, leading to multivalent electrostatic interactions that drastically amplify binding and thereby the immune response. Our results suggest that TLR9 activation and thus TLR9-mediated immune responses can be modulated deterministically.

  7. Prediction of antimicrobial peptides based on sequence alignment and feature selection methods.

    Directory of Open Access Journals (Sweden)

    Ping Wang

    Full Text Available Antimicrobial peptides (AMPs represent a class of natural peptides that form a part of the innate immune system, and this kind of 'nature's antibiotics' is quite promising for solving the problem of increasing antibiotic resistance. In view of this, it is highly desired to develop an effective computational method for accurately predicting novel AMPs because it can provide us with more candidates and useful insights for drug design. In this study, a new method for predicting AMPs was implemented by integrating the sequence alignment method and the feature selection method. It was observed that, the overall jackknife success rate by the new predictor on a newly constructed benchmark dataset was over 80.23%, and the Mathews correlation coefficient is 0.73, indicating a good prediction. Moreover, it is indicated by an in-depth feature analysis that the results are quite consistent with the previously known knowledge that some amino acids are preferential in AMPs and that these amino acids do play an important role for the antimicrobial activity. For the convenience of most experimental scientists who want to use the prediction method without the interest to follow the mathematical details, a user-friendly web-server is provided at http://amp.biosino.org/.

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

    Science.gov (United States)

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

    2016-01-01

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

  9. Insect antimicrobial peptides show potentiating functional interactions against Gram-negative bacteria.

    Science.gov (United States)

    Rahnamaeian, Mohammad; Cytryńska, Małgorzata; Zdybicka-Barabas, Agnieszka; Dobslaff, Kristin; Wiesner, Jochen; Twyman, Richard M; Zuchner, Thole; Sadd, Ben M; Regoes, Roland R; Schmid-Hempel, Paul; Vilcinskas, Andreas

    2015-05-01

    Antimicrobial peptides (AMPs) and proteins are important components of innate immunity against pathogens in insects. The production of AMPs is costly owing to resource-based trade-offs, and strategies maximizing the efficacy of AMPs at low concentrations are therefore likely to be advantageous. Here, we show the potentiating functional interaction of co-occurring insect AMPs (the bumblebee linear peptides hymenoptaecin and abaecin) resulting in more potent antimicrobial effects at low concentrations. Abaecin displayed no detectable activity against Escherichia coli when tested alone at concentrations of up to 200 μM, whereas hymenoptaecin affected bacterial cell growth and viability but only at concentrations greater than 2 μM. In combination, as little as 1.25 μM abaecin enhanced the bactericidal effects of hymenoptaecin. To understand these potentiating functional interactions, we investigated their mechanisms of action using atomic force microscopy and fluorescence resonance energy transfer-based quenching assays. Abaecin was found to reduce the minimal inhibitory concentration of hymenoptaecin and to interact with the bacterial chaperone DnaK (an evolutionarily conserved central organizer of the bacterial chaperone network) when the membrane was compromised by hymenoptaecin. These naturally occurring potentiating interactions suggest that combinations of AMPs could be used therapeutically against Gram-negative bacterial pathogens that have acquired resistance to common antibiotics.

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

    Science.gov (United States)

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

    2013-07-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

  12. The antimicrobial peptide cathelicidin-BF could be a potential therapeutic for Salmonella typhimurium infection.

    Science.gov (United States)

    Xia, Xi; Zhang, Lin; Wang, Yizhen

    2015-02-01

    Resistance is increasing to several critical antimicrobials used to treat Salmonella typhimurium infection, urging people to search for new antimicrobial agents. In this work, we reported the possibility of a potent antimicrobial peptide cathelicidin-BF found in the venom of the snake Bungarus fasciatus in treating Salmonella typhimurium infection. We tested its activity in biological fluids and in vivo using a mouse model of Salmonella typhimurium infection, and examined the effect of cathelicidin-BF on Salmonella invasion to epithelial cells. In addition, the biodistribution of cathelicidin-BF was evaluated by using in vivo optical imaging. The results revealed that cathelicidin-BF was unstable in gastrointestinal tract, but retained substantially active in murine serum. Cathelicidin-BF attenuated the clinical symptoms of Salmonella infected-mice, significantly reduced the number of internalized Salmonella and attenuated Salmonella-induced decreases in TER in epithelial cells. Our results provide a first indication for the potential of cathelicidin-BF as a novel therapeutic option for salmonellosis.

  13. Lipopolysaccharide neutralization by antimicrobial peptides: a gambit in the innate host defense strategy.

    Science.gov (United States)

    Pulido, David; Nogués, M Victòria; Boix, Ester; Torrent, Marc

    2012-01-01

    Antimicrobial peptides (AMPs) are nowadays understood as broad multifunctional tools of the innate immune system to fight microbial infections. In addition to its direct antimicrobial action, AMPs can modulate the host immune response by promoting or restraining the recruitment of cells and chemicals to the infection focus. Binding of AMPs to lipopolysaccharide is a critical step for both their antimicrobial action and their immunomodulatory properties. On the one hand, removal of Gram-negative bacteria by AMPs can be an effective strategy to prevent a worsened inflammatory response that may lead to septic shock. On the other hand, by neutralizing circulating endotoxins, AMPs can successfully reduce nitric oxide and tumor necrosis factor-α production, hence preventing severe tissue damage. Furthermore, AMPs can also interfere with the Toll-like receptor 4 recognition system, suppressing cytokine production and contributing to modulate the inflammatory response. Here, we review the immune system strategies devised by AMPs to avoid an exacerbated inflammatory response and thus prevent a fatal end to the host.

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

    Science.gov (United States)

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

    2014-10-17

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

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

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    Bo-Hye Nam

    2014-10-01

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

  16. Antimicrobial peptides from arachnid venoms and their microbicidal activity in the presence of commercial antibiotics.

    Science.gov (United States)

    Garcia, Francia; Villegas, Elba; Espino-Solis, Gerardo Pavel; Rodriguez, Alexis; Paniagua-Solis, Jorge F; Sandoval-Lopez, Gabriel; Possani, Lourival D; Corzo, Gerardo

    2013-01-01

    Two antimicrobial peptides (AMPs), named La47 and Css54, were isolated from the venom of the spider Lachesana sp. and from the scorpion Centruroides suffusus suffusus, respectively. The primary structures of both La47 and Css54 were determined using N-terminal sequencing and mass spectrometry. La47 is identical to the AMP latarcin 3a obtained previously from the venom of the spider Lachesana tarabaevi, but the primary structure of Css54 is unique having 60% identities to the AMP ponericin-W2 from the venom of the ant Pachycondyla goeldii. Both La47 and Css54 have typical α-helix secondary structures in hydrophobic mimicking environments. The biological activities of both La47 and Css54 were compared with the AMP Pin2 isolated from the venom of the scorpion Pandinus imperator. La47 has lower antimicrobial and hemolytic activities compared with Css54 and Pin2. In addition, La47 and Pin2 were evaluated in the presence of the commercial antibiotics, chloramphenicol, ampicillin, novobiocin, streptomycin and kanamycin. Interestingly, the best antimicrobial combinations were obtained with mixtures of La47 and Pin2 with the antibiotics chloramphenicol, streptomycin and kanamycin, respectively. Furthermore, the novel peptide Css54 was evaluated in the presence of antibiotics used for the treatment of tuberculosis, isoniazid, rifampicin, pyrazinamide and ethambutol. Although the mixtures of Css54 with isoniazid, pyrazinamide or ethambutol inhibit the growth of Staphylococcus aureus, the best effect was found with rifampicin. Overall, these data show a motivating outlook for potential clinical treatments of bacterial infections using AMPs and commercial antibiotics.

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

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    Bobek Libuse A

    2007-11-01

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

  18. Rapid and Reliable Detection of Antimicrobial Peptide Penetration into Gram-Negative Bacteria Based on Fluorescence Quenching▿

    OpenAIRE

    Benincasa, Monica; Pacor, Sabrina; Gennaro, Renato; Scocchi, Marco

    2009-01-01

    In this paper, we describe a rapid flow cytometry method to identify antimicrobial peptides that are internalized into bacterial cells and differentiate them from those that are membrane active. The method was applied to fluorescently labeled Bac71-35 and polymyxin B, whose mechanisms of action are, respectively, based on cell penetration and on membrane binding and permeabilization. Identification of peptides with the former mechanism is of considerable interest for the intracellular deliver...

  19. Rapid and Reliable Detection of Antimicrobial Peptide Penetration into Gram-Negative Bacteria Based on Fluorescence Quenching▿

    Science.gov (United States)

    Benincasa, Monica; Pacor, Sabrina; Gennaro, Renato; Scocchi, Marco

    2009-01-01

    In this paper, we describe a rapid flow cytometry method to identify antimicrobial peptides that are internalized into bacterial cells and differentiate them from those that are membrane active. The method was applied to fluorescently labeled Bac71-35 and polymyxin B, whose mechanisms of action are, respectively, based on cell penetration and on membrane binding and permeabilization. Identification of peptides with the former mechanism is of considerable interest for the intracellular delivery of membrane-impermeant drugs. PMID:19470515

  20. Recombinant expression and solution structure of antimicrobial peptide aurelin from jellyfish Aurelia aurita

    Energy Technology Data Exchange (ETDEWEB)

    Shenkarev, Zakhar O.; Panteleev, Pavel V.; Balandin, Sergey V. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Gizatullina, Albina K.; Altukhov, Dmitry A. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Department of Physicochemical Biology and Biotechnology, Institutskii per., 9, 141700 Dolgoprudny, Moscow Region (Russian Federation); Finkina, Ekaterina I. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Kokryakov, Vladimir N. [Institute of Experimental Medicine, Russian Academy of Medical Sciences, Academica Pavlova str., 12, 197376 Saint-Petersburg (Russian Federation); Arseniev, Alexander S. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Department of Physicochemical Biology and Biotechnology, Institutskii per., 9, 141700 Dolgoprudny, Moscow Region (Russian Federation); Ovchinnikova, Tatiana V., E-mail: ovch@ibch.ru [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Department of Physicochemical Biology and Biotechnology, Institutskii per., 9, 141700 Dolgoprudny, Moscow Region (Russian Federation)

    2012-12-07

    Highlights: Black-Right-Pointing-Pointer Aurelin was overexpressed in Escherichia coli, and its spatial structure was studied by NMR. Black-Right-Pointing-Pointer Aurelin compact structure encloses helical regions cross-linked by three disulfide bonds. Black-Right-Pointing-Pointer Aurelin shows structural homology to the BgK and ShK toxins of sea anemones. Black-Right-Pointing-Pointer Aurelin binds to the anionic lipid vesicles, but does not interact with zwitterionic ones. Black-Right-Pointing-Pointer 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 {sup 15}N-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 3{sub 10}-helix and two {alpha}-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 {alpha}-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{sup +}-channels. The obtained data permit to correlate the modest antibacterial properties and membrane activity of aurelin.

  1. IL-10 inhibits while calcitriol reestablishes placental antimicrobial peptides gene expression.

    Science.gov (United States)

    Olmos-Ortiz, Andrea; Noyola-Martínez, Nancy; Barrera, David; Zaga-Clavellina, Verónica; Avila, Euclides; Halhali, Ali; Biruete, Benjamín; Larrea, Fernando; Díaz, Lorenza

    2015-04-01

    IL-10 and calcitriol help to achieve a successful pregnancy by suppressing active maternal immunity; however, these factors exert opposite effects upon microbial infections. In the skin and immune cells, IL-10 downregulates β-defensins while calcitriol induces cathelicidin gene expression in various tissues including placenta. Though, the regulation of human placental β-defensins by IL-10 and calcitriol has not been studied. Therefore, we explored the regulation of these antimicrobial peptides expression in cultured placental cells by calcitriol and IL-10 alone and combined. Real time PCR showed that calcitriol stimulated, while IL-10 inhibited, β-defensins and cathelicidin gene expression (Pantimicrobial peptides gene expression above control values, overriding IL-10 inhibitory effects. Calcitriol downregulated endogenous IL-10 secretion. Interestingly, calcitriol and TNF-α cooperatively enhanced β-defensins, while TNF-α reduced basal and calcitriol-stimulated cathelicidin gene expression. In summary, calcitriol and IL-10 exerted opposite effects on antimicrobial peptides expression in the human placenta, suggesting that unbalanced production of IL-10 and calcitriol could be deleterious to innate immune responses during gestation. Our results suggest that calcitriol enhancement of placental defenses involves two mechanisms: (1) downregulation of IL-10 secretion and (2) direct upregulation of β-defensins and cathelicidin gene expression. Considering that IL-10 and calcitriol differentially regulate the innate immune response in the placenta, in the case of an infection, calcitriol might restrict IL-10 permissive actions towards microbial invasion while restrains inflammation, allowing for pregnancy to continue in quiescence. These results strongly advice maternal vitamin D sufficiency during pregnancy.

  2. Implications of lipid monolayer charge characteristics on their selective interactions with a short antimicrobial peptide.

    Science.gov (United States)

    Ciumac, Daniela; Campbell, Richard A; Xu, Hai; Clifton, Luke A; Hughes, Arwel V; Webster, John R P; Lu, Jian R

    2017-02-01

    Many antimicrobial peptides (AMPs) target bacterial membranes and they kill bacteria by causing structural disruptions. One of the fundamental issues however lies in the selective responses of AMPs to different cell membranes as a lack of selectivity can elicit toxic side effects to mammalian host cells. A key difference between the outer surfaces of bacterial and mammalian cells is the charge characteristics. We report a careful study of the binding of one of the representative AMPs, with the general sequence G(IIKK)4I-NH2 (G4), to the spread lipid monolayers of DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and DPPG (1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt)) mimicking the charge difference between them, using the combined measurements from Langmuir trough, Brewster angle microscopy (BAM) and neutron reflection (NR). The difference in pressure rise upon peptide addition into the subphase clearly demonstrated the different interactions arising from different lipid charge features. Morphological changes from the BAM imaging confirmed the association of the peptide into the lipid monolayers, but there was little difference between them. However, NR studies revealed that the peptide bound 4 times more onto the DPPG monolayer than onto the DPPC monolayer. Importantly, whilst the peptide could only be associated with the head groups of DPPC it was well penetrated into the entire DPPG monolayer, showing that the electrostatic interaction strengthened the hydrophobic interaction and that the combined molecular interactive processes increased the power of G4 in disrupting the charged membranes. The results are discussed in the context of general antibacterial actions as observed from other AMPs and membrane lytic actions.

  3. Enhancement of cytotoxicity of antimicrobial peptide magainin Ⅱ in tumor cells by bombesin-targeted delivery

    Institute of Scientific and Technical Information of China (English)

    Shan LIU; Hao YANG; Lin WAN; Hua-wei CAI; Sheng-fu LI; You-ping LI; Jing-qiu CHENG; Xiao-feng LU

    2011-01-01

    Aim: To investigate whether the conjugation of magainin II(MG2),an antimicrobial peptides(AMPs),to the tumor-homing peptide bombesin could enhance its cytotoxicity in tumor cells.Methods: A magainin Ⅱ-bombesin conjugate(MG2B)was constructed by attaching magainin Ⅱ(MG2)to bombesin at its N-terminus.The peptides were synthesized using Fmoc-chemistry.The in vitro cytotoxicity of the peptide in cancer cells was quantitatively determined using the CCK-8 celt counting kit.Moreover,the in vivo antitumor effect of the peptide was determined in tumor xenograft models.Results: The IC50 of MG2B for cancer cells(10-15 μmol/L)was at least 10 times lower than the IC50 of unconjugated MG2(125μmol/L).Moreover,the binding affinity of MG2B for cancer cells was higher than that of unconjugated MG2.In contrast,conjugation to a bombesin analog lacking the receptor-binding domain failed to increase the cytotoxicity of MG2,suggesting that bombesin conjugation enhances the cytotoxicity of MG2 in cancer cells through improved binding.Indeed,MG2B selectively induced cell death in cancer cells in vitro with the IC50 ranging from 10 to 15 μmol/L,which was about 6-10 times lower than the IC50 for normal cells.MG2B(20mg/kg per day,intratumorally injected for 5 d)also exhibited antitumor effects in mice bearing MCF-7 tumor grafts.The mean weights of tumor grafts in MG2B-and PBS-treated mice were 0.21±0.05 g and 0.59±0.12 g,respectively.Conclusion: The results suggest that conjugation of AMPs to bombesin might be an alternative approach for targeted cancer therapy.

  4. 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.

  5. 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.

  6. Effect of cholesterol on the interaction of the amphibian antimicrobial peptide DD K with liposomes.

    Science.gov (United States)

    Verly, Rodrigo M; Rodrigues, Magali A; Daghastanli, Katia Regina P; Denadai, Angelo Márcio L; Cuccovia, Iolanda M; Bloch, Carlos; Frézard, Frédéric; Santoro, Marcelo M; Piló-Veloso, Dorila; Bemquerer, Marcelo P

    2008-01-01

    DD K is an antimicrobial peptide previously isolated from the skin of the amphibian Phyllomedusa distincta. The effect of cholesterol on synthetic DD K binding to egg lecithin liposomes was investigated by intrinsic fluorescence of tryptophan residue, measurements of kinetics of 5(6)-carboxyfluorescein (CF) leakage, dynamic light scattering and isothermal titration microcalorimetry. An 8 nm blue shift of tryptophan maximum emission fluorescence was observed when DD K was in the presence of lecithin liposomes compared to the value observed for liposomes containing 43 mol% cholesterol. The rate and the extent of CF release were also significantly reduced by the presence of cholesterol. Dynamic light scattering showed that lecithin liposome size increase from 115 to 140 nm when titrated with DD K but addition of cholesterol reduces the liposome size increments. Isothermal titration microcalorimetry studies showed that DD K binding both to liposomes containing cholesterol as to liposomes devoid of it is more entropically than enthalpically favored. Nevertheless, the peptide concentration necessary to furnish an adjustable titration curve is much higher for liposomes containing cholesterol at 43 mol% (2 mmol L(-1)) than in its absence (93 micromol L(-1)). Apparent binding constant values were 2160 and 10,000 L mol(-1), respectively. The whole data indicate that DD K binding to phosphatidylcholine liposomes is significantly affected by cholesterol, which contributes to explain the low hemolytic activity of the peptide.

  7. 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.

  8. Antimicrobial peptide production and plant-based expression systems for medical and agricultural biotechnology.

    Science.gov (United States)

    Holaskova, Edita; Galuszka, Petr; Frebort, Ivo; Oz, M Tufan

    2015-11-01

    Antimicrobial peptides (AMPs) are vital components of the innate immune system of nearly all living organisms. They generally act in the first line of defense against various pathogenic bacteria, parasites, enveloped viruses and fungi. These low molecular mass peptides are considered prospective therapeutic agents due to their broad-spectrum rapid activity, low cytotoxicity to mammalian cells and unique mode of action which hinders emergence of pathogen resistance. In addition to medical use, AMPs can also be employed for development of innovative approaches for plant protection in agriculture. Conferred disease resistance by AMPs might help us surmount losses in yield, quality and safety of agricultural products due to plant pathogens. Heterologous expression in plant-based systems, also called plant molecular farming, offers cost-effective large-scale production which is regarded as one of the most important factors for clinical or agricultural use of AMPs. This review presents various types of AMPs as well as plant-based platforms ranging from cell suspensions to whole plants employed for peptide production. Although AMP production in plants holds great promises for medicine and agriculture, specific technical limitations regarding product yield, function and stability still remain. Additionally, establishment of particular stable expression systems employing plants or plant tissues generally requires extended time scale for platform development compared to certain other heterologous systems. Therefore, fast and promising tools for evaluation of plant-based expression strategies and assessment of function and stability of the heterologously produced AMPs are critical for molecular farming and plant protection.

  9. Assessment of antimicrobial (host defense) peptides as anti-cancer agents.

    Science.gov (United States)

    Douglas, Susan; Hoskin, David W; Hilchie, Ashley L

    2014-01-01

    Cationic antimicrobial (host defense) peptides (CAPs) are able to kill microorganisms and cancer cells, leading to their consideration as