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The role of disulfide bridges in the 3-D structures of the antimicrobial peptides gomesin and protegrin-1: a molecular dynamics study

CASTRO, J. R. M.; FUZO, C. A.; DEGREVE, L.; CALIRI, A.
Fonte: FUNPEC-EDITORA Publicador: FUNPEC-EDITORA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.48%
Some antimicrobial peptides have a broad spectrum of action against many different kinds of microorganisms. Gomesin and protegrin-1 are examples of such antimicrobial peptides, and they were studied by molecular dynamics in this research. Both have a beta-hairpin conformation stabilized by two disulfide bridges and are active against Gram-positive and Gram-negative bacteria, as well as fungi. In this study, the role of the disulfide bridge in the maintenance of the tertiary peptide structure of protegrin-1 and gomesin is analyzed by the structural characteristics of these peptides and two of their respective variants, gomy4 and proty4, in which the four cysteines are replaced by four tyrosine residues. The absence of disulfide bridges in gomy4 and proty4 is compensated by overall reinforcement of the original hydrogen bonds and extra attractive interactions between the aromatic rings of the tyrosine residues. The net effects on the variants with respect to the corresponding natural peptides are: i) maintenance of the original beta-hairpin conformation, with great structural similarities between the mutant and the corresponding natural peptide; ii) combination of positive F and. Ramachandran angles within the hairpin head region with a qualitative change to a combination of positive (F) and negative (.) angles...

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

SACRAMENTO, R. S.; MARTINS, R. M.; MIRANDA, A.; DOBROFF, A. S. S.; DAFFRE, S.; FORONDA, A. S.; FREITAS, D. De; SCHENKMAN, S.
Fonte: CAMBRIDGE UNIV PRESS Publicador: CAMBRIDGE UNIV PRESS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.45%
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 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.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Cientifico Tecnologico (CNPq)...

Leishmanicidal Activity and Immobilization of dermaseptin 01 antimicrobial peptides in ultrathin films for nanomedicine applications

ZAMPA, Maysa F.; ARAUJO, Ines M. S.; COSTA, Vladimir; COSTA, Carlos H. Nery; SANTOS JR., Jose Ribeiro; ZUCOLOTTO, Valtencir; EIRAS, Carla; LEITE, Jose Roberto S. A.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Antimicrobial peptides (AMPs) are essential for the innate immune system of eukaryotes, imparting protection against pathogens and their proliferation in host organisms. The recent interest in AMPs as active materials in bionanostructures is due to the properties shown by these biological molecules, such as the presence of an alpha-helix structure and distribution of positive charges along the chain. In this study the antimicrobial peptide dermaseptin 01 (DS 01), from the skin secretion of Phyllomedusa hypochondrialis frogs was immobilized in nanostructured layered films in conjunction with nickel tetrasulfonated phthalocyanines. The leishmanicidal activity of DS 01 was confirmed using kinetic essays, in which DS 01 promoted death of all metacyclic promastigote cells in 45 minutes. Surprisingly, the immobilized DS 01 molecules displayed electroactivity, as revealed by electrochemical experiments, in which an oxidation peak at about 0.61 V was observed for a DS 01 monolayer deposited on top of a conductive electrode. Such electroactivity was used to investigate the sensing abilities of the nanostructured films toward Leishmania. We observed an increase in the oxidation current as a function of number of Leishmania cells in the electrolytic solution at concentrations down to 10(3) cells/mL. The latter is indicative that the use of AMPs immobilized in electroactive nanostructured films may be of interest for applications in the pharmaceutical industry and diagnosis.; FAPEPI; Fundação de Amparo à Pesquisa do Estado do Piauí (FAPEPI); FAPESP; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); CAPES; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); CNPq; Ministério da Ciência...

Antimicrobial peptides and nitric oxide production by neutrophils from periodontitis subjects

Mariano, F.S.; Campanelli, A.P.; Nociti Jr., F.H.; Mattos-Graner, R.O.; Gonçalves, R.B.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.42%
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...

Genes codificadores dos peptídeos antimicrobianos e de outras proteínas envolvidas na resposta imune de in Apis mellifera; Genes encoding antimicrobial peptides and immune-related proteins in Apis mellifera.

Lourenço, Anete Pedro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 11/01/2008 PT
Relevância na Pesquisa
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Os insetos desenvolveram um sistema imune eficiente contra parasitas e patógenos, que compreende a resposta celular e a humoral. Os mecanismos celulares envolvem a fagocitose e a encapsulação pelos hemócitos, enquanto que as respostas humorais incluem a ativação da Profenoloxidase, e a síntese pelo corpo gorduroso dos peptídeos antimicrobianos, que são liberados na hemolinfa. Duas vias de sinalização intracelular, Toll e Imd, controlam a expressão dos genes codificadores dos peptídeos antimicrobianos. A análise do Genoma da abelha Apis mellifera permitiu a identificação dos genes dessas vias. No entanto, pouco se conhece do mecanismo de resposta imune nessas abelhas. Desta maneira, nos propusemos analisar a transcrição de genes efetores da resposta imune (abaecina, hymenoptaecina, defensina, transferrina, profenoloxidase), assim como os genes integrantes das vias de sinalização, tais como os genes de reconhecimento de microorganismos (PGRP, GNBP) e ainda, os de sinalização (cactus, relish, dorsal 1-B). Avaliamos também possíveis proteínas implicadas na resposta imune, como as proteínas de estocagem Vitelogenina, Hexamerina 70a, Lipoforina I/II e Lipoforina III. Finalmente, analisamos o efeito da nutrição e do envelhecimento sobre a imunidade em abelhas. Para análise da expressão dos genes das vias de sinalização...

Caracterização de proteinases envolvidas na geração de peptídeos antimicrobianos no intestino de Rhipicephalus (Boophilus) microplus.; CE. Characterization of proteinases involved in the generation of antimicrobial peptides in the gut of Rhipicephalus (Boophilus) microplus.

Cruz, Carlos Eduardo Silva da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/02/2010 PT
Relevância na Pesquisa
66.4%
Sabe-se que a hemoglobina é uma rica fonte de peptídeos antimicrobianos (hemocidinas). A primeira hemocidina derivada da hemoglobina bovina caracterizada em carrapatos foi o peptídeo Hb33-61, que é ativo contra bactérias gram-positivas e fungos. Acredita-se que tais hemocidinas sejam geradas proteoliticamente no intestino do carrapato. Neste trabalho nós caracterizamos bioquimicamente uma catepsina D, designada BmAP. A análise da expressão gênica por qPCR mostrou que ela é expressa predominantemente no intestino. Através de LC-MS/MS, determinamos a especificidade de clivagem da BmAP utilizando Hb bovina, e verificamos que resíduos hidrofóbicos foram preferencialmente clivados nos subsítios P1 e P1. Também investigamos a especificidade de clivagem da catepsina L intestinal BmCL1, utilizando uma biblioteca combinatória de tetrapeptídeos e através de hemoglobinólise in vitro. A BmCL1 preferiu resíduos alifáticos no P2 e polares no P1 e P1. Além disso, hidrolisou a cadeia da Hb bovina entre A63/A64, gerando peptídeos com estrutura primária similar ao Hb 33-61. A hemoglobinólise com a BmAP e/ou BmCL1 resultou na formação de algumas hemocidinas, corroborando a hipótese do seu envolvimento na geração endógena de peptídeos antimicrobianos.; It is known that hemoglobin is a rich source of antimicrobial peptides (hemocidins). The first hemoglobin-derived hemocidin characterized in ticks was the peptide Hb33-61...

Isolamento e caracterização de peptídeos antimicrobianos derivados da digestão da hemoglobina em Rhipicephalus (Boophilus microplus); Isolation and characterization of antimicrobial peptides produced during hemoglobin digestion on Rhipicephalus (Boophilus) microplus.

Silva, Rodrigo Caetano Belmonte da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/02/2010 PT
Relevância na Pesquisa
66.36%
A hemoglobina possuí um grande potencial antimicrobiano, sendo os peptídeos antimicrobianos (AMPs) derivados de proteínas contêm o grupamento heme denominados hemocidinas. O carrapato bovino Rhipicephalus (Boophilus) microplus é capaz de adquirir e processar grandes quantidades de sangue para seu metabolismo. Neste trabalho, purificamos hemocidinas produzidas no tubo digestório do carrapato. Identificamos 10 fragmentos da hemoglobina bovina que possuem atividade contra Candida albicans (Hb 1-94, 3-94, 1-87, 93-141, 102-141, 103-141, 107-141, 104-141 e 98-114 e Hb"beta" 127-145). Determinamos que todos os peptídeos apresentam um alto conteúdo de aminoácidos básicos, além de uma estrutura secundária em "alfa"-hélice, características encontradas em outros AMPs. Verificamos também que as duas principais proteases que atuam na produção das hemocidinas são uma cisteíno- e uma aspártico-proteinase. A identificação de diversas hemocidinas, no tubo digestório de R. (Boophilus) microplus, indica uma possível participação das hemocidinas na proteção contra microorganismos; The hemoglobin posses a great potential as an antimicrobial, being denominated hemocidins the antimicrobial peptides (AMPs) derived from heme containing proteins. The cattle tick Rhipicephalus (Boophilus) microplus is capable of processing large amounts of blood to its own metabolism. In this work we purified the hemocidins that are produced in the tick gut. We identified 10 fragments from bovine hemoglobin that presents activity towards Candida albicans (Hb 1-94...

Jelleines: a family of antimicrobial peptides from the Royal Jelly of honeybees (Apis mellifera)

Fontana, R.; Mendes, M. A.; de Souza, B. M.; Konno, K.; Cesar, LMM; Malaspina, O.; Palma, Mario Sergio
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 919-928
ENG
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Four antimicrobial peptides were purified from Royal Jelly of honeybees, by using reverse phase-HPLC and sequenced by using Q-Tof-MS/MS: PFKLSLHL-NH2 (Jelleine-I), TPFKLSLHL-NH2 (Jelleine-II), EPFKLSLHL-NH2 (Jelleine-III), and TPFKLSLH-NH2 (Jelleine-IV). The peptides were synthesized on-solid phase, purified and submitted to different biological assays: antimicrobial activity, mast cell degranulating activity and hemolysis. The Jelleines-I-III presented exclusively antimicrobial activities against yeast, Gram+ and Gram- bacteria; meanwhile, Jelleine-IV was not active in none of the assays performed. These peptides do not present any similarity with the other antimicrobial peptides from the honeybees; they are produced constitutively by the workers and secreted into Royal Jelly. (C) 2004 Elsevier B.V. All rights reserved.

Combinatorial synthesis and directed evolution applied to the production of alpha-helix forming antimicrobial peptides analogues

Castro, Mariana S.; Cilli, Eduardo Maffud; Fontes, Wagner
Fonte: Bentham Science Publ Ltd Publicador: Bentham Science Publ Ltd
Tipo: Revisão Formato: 473-478
ENG
Relevância na Pesquisa
66.45%
Antimicrobial peptides (AMPs) are effector molecules of innate immune systems found in different groups of organisms, including microorganisms, plants, insects, amphibians and humans. These peptides exhibit several structural motifs but the most abundant AMPs assume an amphipathic alpha-helical structure. The alpha-helix forming antimicrobial peptides are excellent candidates for protein engineering leading to an optimization of their biological activity and target specificity. Nowadays several approaches are available and this review deals with the use of combinatorial synthesis and directed evolution in order to provide a high-throughput source of antimicrobial peptides analogues with enhanced lytic activity and specificity.

Antimicrobial peptides and nitric oxide production by neutrophils from periodontitis subjects

Mariano, F. S.; Campanelli, A. P.; Nociti, F. H., Jr.; Mattos-Graner, R. O.; Goncalves, R. B.
Fonte: Assoc Bras Divulg Cientifica; Sao Paulo Publicador: Assoc Bras Divulg Cientifica; Sao Paulo
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.42%
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...

Escherichia coli expression and purification of four antimicrobial peptides fused to a family 3 carbohydrate-binding module (CBM) from Clostridium thermocellum

Guerreiro, Catarina I. P. D.; Fontes, Carlos M. G. A.; Gama, F. M.; Domingues, Lucília
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /05/2008 ENG
Relevância na Pesquisa
66.32%
Antimicrobial peptides (AMPs) are molecules that act in a wide range of physiological defensive mechanisms developed to counteract bacteria, fungi, parasites and viruses. Several hundreds of AMPs have been identified and characterized. These molecules are presently gaining increasing importance, as a consequence of their remarkable resistance to microorganism adaptation. Carbohydrate-binding modules (CBMs) are non-catalytic domains that anchor glycoside hydrolases into complex carbohydrates. Clostridium thermocellum produces a multi-enzyme complex of cellulases and hemicellulases, termed the cellulosome, which is organized by the scaffoldin protein CipA. Binding of the cellulosome to the plant cell wall results from the action of CipA family 3 CBM (CBM3), which presents a high affinity for crystalline cellulose. Here CipA family 3 CBM was fused to four different AMPs using recombinant DNA technology and the fusion recombinant proteins were expressed at high levels in Escherichia coli cells. CBM3 does not present antibacterial activity and does not bind to the bacterial surface. However, the four recombinant proteins retained the ability to bind cellulose, suggesting that CBM3 is a good candidate polypeptide to direct the binding of AMPs into cellulosic supports. A comprehensive characterization of the antimicrobial activity of the recombinant fusion proteins is currently under evaluation.; Fundação para a Ciência e a Tecnologia (FCT); Instituto de Tecnologia Química e Biológica,

Identification of novel GAPDH-derived antimicrobial peptides secreted by Saccharomyces cerevisiae and involved in wine microbial interactions

Branco, Patrícia; Francisco, Diana; Chambon, Christophe; Hébraud, Michel; Arneborg, Nils; Almeida, Maria G.; Caldeira, Jorge; Albergaria, Helena
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2014 ENG
Relevância na Pesquisa
66.31%
Saccharomyces cerevisiae plays a primordial role in alcoholic fermentation and has a vastworldwide application in the production of fuel-ethanol, food and beverages. The dominance of S. cerevisiae over other microbial species during alcoholic fermentations has been traditionally ascribed to its higher ethanol tolerance. However, recent studies suggested that other phenomena, such as microbial interactions mediated by killer-like toxins, might play an important role. Here we show that S. cerevisiae secretes antimicrobial peptides (AMPs) during alcoholic fermentation that are active against a wide variety of wine-related yeasts (e.g. Dekkera bruxellensis) and bacteria (e.g. Oenococcus oeni). Mass spectrometry analyses revealed that these AMPs correspond to fragments of the S. cerevisiae glyceraldehyde 3-phosphate dehydrogenase (GAPDH) protein. The involvement of GAPDH-derived peptides in wine microbial interactions was further sustained by results obtained in mixed cultures performed with S. cerevisiae single mutants deleted in each of the GAPDH codifying genes (TDH1-3) and also with a S. cerevisiae mutant deleted in the YCA1 gene, which codifies the apoptosis-involved enzyme metacaspase. These findings are discussed in the context of wine microbial interactions...

Dominance of Saccharomyces cerevisiae in wine fermentations: secretion of antimicrobial peptides and microbial interactions 

Albergaria, Helena; Branco, Patrícia; Francisco, Diana; Coutinho, Rute; Monteiro, Margarida; Malfeito-Ferreira, M.; Arneborg, Nils; Almeida, Maria G.; Caldeira, Jorge
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 ENG
Relevância na Pesquisa
66.27%
In present work we investigated the antagonistic effect by S. cerevisiae against several wine-related microbial species vis-à-vis the secretion of antimicrobial peptides (AMPs).

Antimicrobial peptides from Saccharomyces cerevisiae induce physiological changes in Hanseniaspora guilliermondii

Branco, Patrícia; Albergaria, Helena; Arneborg, Nils
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 ENG
Relevância na Pesquisa
66.27%
Saccharomyces cerevisiae secretes antimicrobial peptides (AMPs) during alcoholic fermentation that are active against other wine-related yeasts (e.g. Hanseniaspora guilliermondii) (Albergaria et al., 2010) and bacteria (e.g. Oenococcus oeni) (Osborne and Edwards, 2007). In the present study we assessed the physiological changes induced by those AMPs on sensitive yeast cells of Hanseniaspora guilliermondii, namely membrane permeability and intracellular pH (pHi) alterations. Membrane permeability was evaluated by staining cells with propidium iodide (PI) and pHi by the fluorescence ratio imaging microscopy (FRIM) technique (Guldfeldt and Arneborg, 1998). Results showed that after 20 min of incubation with inhibitory concentrations of AMPs, the average pHi of cells dropped from 6.5 to 5.4. After 8 h of incubation, 32% of the cells had lost their ĢpH (=pHi-pHext) and after 24 h that percentage rose to 77%. The culturability (plating) and viability (PI staining) of the sensitive yeast cells also decreased in the presence of the AMPs. After 24 h of exposure to AMPs, 61% of the cells were dead (PI-stained) and the number of viable cells fell from 1 ~105 to 1.5 CFU/ml, which means that virtually all cells (99.999%) became unculturable but a sub-population of 39% of cells remained in a viable but non-culturable (VBNC) state. However...

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

Castañeda-Delgado,Julio E; Cervantes-Villagrana,Alberto; Serrano-Escobedo,Carmen J; Frausto-Lujan,Isabel; Rivas-Santiago,Cesar; Enciso-Moreno,Jose A; Rivas-Santiago,Bruno
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2014 EN
Relevância na Pesquisa
66.31%
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.

Antimicrobial peptides and nitric oxide production by neutrophils from periodontitis subjects

Mariano,F.S.; Campanelli,A.P.; Nociti Jr.,F.H.; Mattos-Graner,R.O.; Gonçalves,R.B.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2012 EN
Relevância na Pesquisa
66.42%
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...

Interaction of antimicrobial peptides from Australian amphibians with lipid membranes

Marcotte, I.; Wegener, K.; Lam, Y.H.; Chia, C.; de Planque, M.; Bowie, J.; Auger, M.; Separovic, F.
Fonte: Elsevier Sci Ireland Ltd Publicador: Elsevier Sci Ireland Ltd
Tipo: Artigo de Revista Científica
Publicado em //2003 EN
Relevância na Pesquisa
66.42%
Solid-state NMR and CD spectroscopy were used to study the effect of antimicrobial peptides (aurein 1.2, citropin 1.1, maculatin 1.1 and caerin 1.1) from Australian tree frogs on phospholipid membranes. 31P NMR results revealed some effect on the phospholipid headgroups when the peptides interact with DMPC/DHPC (dimyristoylphosphatidylcholine/dihexanoylphosphatidylcholine) bicelles and aligned DMPC multilayers. 2H NMR showed a small effect of the peptides on the acyl chains of DMPC in bicelles or aligned multilayers, suggesting interaction with the membrane surface for the shorter peptides and partial insertion for the longer peptides. 15N NMR of selectively labelled peptides in aligned membranes and oriented CD spectra indicated an α-helical conformation with helix long axis ~50° to the bilayer surface at high peptide concentrations. The peptides did not appear to insert deeply into PC membranes, which may explain why these positively charged peptides preferentially lyse bacterial rather than eucaryotic cells.; http://www.elsevier.com/wps/find/journaldescription.cws_home/506036/description#description; Isabelle Marcotte, Kate L. Wegener, Yuen-Han Lam, Brian C. S. Chia, Maurits R. R. de Planque, John H. Bowie, Michèle Auger and Frances Separovic; Copyright © 2002 Elsevier Science Ireland Ltd. All rights reserved.

Differentielle Induktion antimikrobieller Peptide in der Haut durch kommensale und pathogene Staphylokokken; Skin commensal and pathogenic staphylocooci induce antimicrobial peptides differentially

Wanke, Ines
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
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Obwohl es zunehmend klinische Evidenz gibt, dass probiotische oder kommensale Bakterien wichtig für die Infektionsabwehr pathogener Mikroorganismen sind, besteht über die zugrundeliegenden biologischen Mechanismen Unklarheit. In der vorliegenden Arbeit konnte gezeigt werden, dass kommensale und pathogene Staphylokokken in primären humanen Keratinozyten die antimikrobiellen Peptide/Proteine HBD-3 und RNase7 unterschiedlich stark induzieren konnten. Dazu aktivierten sie verschiedene Signalwege. S. epidermidis führte nur zu einer geringen Induktion von HBD-3 und RNase7, welche über die TLR2/NFkappaB- und EGFR-Signalwege vermittelt wurde. S .aureus führte hingegen zu einer starken Erhöhung der HBD-3 und RNase7 Expression, die jedoch unabhängig von den genannten Signalwegen erfolgte. Stattdessen war dieses Pathogen in der Lage, den NFkappaB Signalweg zu hemmen, indem der NFkappaB-Inhibitor Ikappab vermehrt exprimiert wurde. Kommensale Staphylokokken waren in der Lage, diese Inhibition des NFkappaB-Signalweges aufzuheben. Dies führte zu einer Amplifikation der antimikrobiellen Antwort der primären humanen Keratinozyten. Somit können die von beiden Staphylokkenspezies aktivierten Signalwege synergistisch zusammenwirken und zu einer verbesserten Infektionsabwehr führen. Im Verlauf dieser Arbeit wurde ein epikutanes Hautinfektionsmodell in der Maus etabliert...

In vitro antiviral activity of antimicrobial peptides against herpes simplex virus 1, adenovirus, and rotavirus

Carriel-Gomes,Márcia Cristina; Kratz,Jadel Müller; Barracco,Margherita Anna; Bachére,Evelyne; Barardi,Célia Regina Monte; Simões,Cláudia Maria Oliveira
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2007 EN
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Peptides with broad-spectrum antimicrobial activity, known as antimicrobial peptides, have been isolated from distinct organisms. This paper describes the in vitro evaluation of the cytotoxicity and antiviral activity of nine peptides with different structures and origins against herpes simplex virus type 1, human adenovirus respiratory strain, and rotavirus SA11. Most of the evaluated peptides presented antiviral activity but they were only active near cytotoxic concentrations. Nevertheless, these results seem promising, and further modifications on the peptide's structures may improve their selectivity and reduce their cytotoxicity.

Biotechnological potential of antimicrobial peptides from flowers

Tavares, Letícia Stephan; Santos, Marcelo de Oliveira; Viccini, Lyderson Facio; Moreira, João Suender; Miller, Robert Neil Gerard; Franco, Octávio Luiz
Fonte: Universidade Católica de Brasília Publicador: Universidade Católica de Brasília
Tipo: Artigo de Revista Científica Formato: Texto
EN
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Flowers represent a relatively unexplored source of antimicrobial peptides of biotechnological potential. This review focuses on flower-derived defense peptide classes with inhibitory activity towards plant pathogens. Small cationic peptides display diverse activities, including inhibition of digestive enzymes and bacterial and/or fungal inhibition. Considerable research is ongoing in this area, with natural crop plant defense potentially improved through the application of transgenic technologies. In this report, comparisons were made of peptide tertiary structures isolated from diverse flower species. A summary is provided of molecular interactions between flower peptides and pathogens, which include the role of membrane proteins and lipids. Research on these peptides is contributing to our understanding of pathogen resistance mechanisms, which will, given the perspectives for plant genetic modification, contribute long term to plant genetic improvement for increased resistance to diverse pathogens.