Academic literature on the topic 'Antimicrobial PEPTIDES IN VIVO'

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Journal articles on the topic "Antimicrobial PEPTIDES IN VIVO"

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Bals, Robert, Daniel J. Weiner, A. David Moscioni, Rupalie L. Meegalla, and James M. Wilson. "Augmentation of Innate Host Defense by Expression of a Cathelicidin Antimicrobial Peptide." Infection and Immunity 67, no. 11 (November 1, 1999): 6084–89. http://dx.doi.org/10.1128/iai.67.11.6084-6089.1999.

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ABSTRACT Antimicrobial peptides, such as defensins or cathelicidins, are effector substances of the innate immune system and are thought to have antimicrobial properties that contribute to host defense. The evidence that vertebrate antimicrobial peptides contribute to innate immunity in vivo is based on their expression pattern and in vitro activity against microorganisms. The goal of this study was to investigate whether the overexpression of an antimicrobial peptide results in augmented protection against bacterial infection. C57BL/6 mice were given an adenovirus vector containing the cDNA for LL-37/hCAP-18, a human cathelicidin antimicrobial peptide. Mice treated with intratracheal LL-37/hCAP-18 vector had a lower bacterial load and a smaller inflammatory response than did untreated mice following pulmonary challenge with Pseudomonas aeruginosa PAO1. Systemic expression of LL-37/hCAP-18 after intravenous injection of recombinant adenovirus resulted in improved survival rates following intravenous injection of lipopolysaccharide with galactosamine or Escherichia coli CP9. In conclusion, the data demonstrate that expression of an antimicrobial peptide by gene transfer results in augmentation of the innate immune response, providing support for the hypothesis that vertebrate antimicrobial peptides protect against microorganisms in vivo.
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Schouten, Gina, Felix Paulussen, Oscar Kuipers, Wilbert Bitter, Tom Grossmann, and Peter van Ulsen. "Stapling of Peptides Potentiates the Antibiotic Treatment of Acinetobacter baumannii In Vivo." Antibiotics 11, no. 2 (February 19, 2022): 273. http://dx.doi.org/10.3390/antibiotics11020273.

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The rising incidence of multidrug resistance in Gram-negative bacteria underlines the urgency for novel treatment options. One promising new approach is the synergistic combination of antibiotics with antimicrobial peptides. However, the use of such peptides is not straightforward; they are often sensitive to proteolytic degradation, which greatly limits their clinical potential. One approach to increase stability is to apply a hydrocarbon staple to the antimicrobial peptide, thereby fixing them in an α-helical conformation, which renders them less exposed to proteolytic activity. In this work we applied several different hydrocarbon staples to two previously described peptides shown to act on the outer membrane, L6 and L8, and tested their activity in a zebrafish embryo infection model using a clinical isolate of Acinetobacter baumannii as a pathogen. We show that the introduction of such a hydrocarbon staple to the peptide L8 improves its in vivo potentiating activity on antibiotic treatment, without increasing its in vivo antimicrobial activity, toxicity or hemolytic activity.
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Kopeykin, P. M., M. S. Sukhareva, N. V. Lugovkina, and O. V. Shamova. "CHEMICAL SYNTHESIS AND ANALYSIS OF ANTIMICROBIAL AND HEMOLYTIC ACTIVITY OF STRUCTURAL ANALOGOUS OF A PEPTIDE PROTEGRIN 1." Medical academic journal 19, no. 1S (December 15, 2019): 169–70. http://dx.doi.org/10.17816/maj191s1169-170.

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Search for new tools for combating infectious diseases and investigation of molecular mechanisms of their antimicrobial action in in vitro and in vivo models are the urgent tasks of experimental medicine and pathophysiology. A promising direction for the development of new effective antibiotic drugs is creation of analogues of natural protective molecules that provide a host defense against pathogenic bacteria, in particular analogues of antimicrobial peptides of the innate immune system. The aim of our work was design, chemical synthesis and characterization of antimicrobial and hemolytic activity of a peptide protegrin 1 (PG1) structural variants. Three analogues of PG1 were produced and studied, it was shown that two PG1 variants exhibit a high activity against antibiotic-resistant bacteria. A comparative analysis of the hemolytic activity of the peptides towards human erythrocytes was carried out. The ways of further work directed to creation of novel antimicrobials based on a natural peptide PG1 for combating drug-resistant bacteria are outlined.
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Hu, Alvin. "Conjugation of Silver Nanoparticles With De Novo–Engineered Cationic Antimicrobial Peptides: Exploratory Proposal." JMIR Research Protocols 10, no. 12 (December 8, 2021): e28307. http://dx.doi.org/10.2196/28307.

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Background Cationic antimicrobial peptides have broad antimicrobial activity and provide a novel way of targeting multidrug-resistant bacteria in the era of increasing antimicrobial resistance. Current developments show positive prospects for antimicrobial peptides and silver nanoparticles (AgNPs) individually. Objective The primary objective is to propose another method for enhancing antimicrobial activity by conjugating AgNPs with cationic antimicrobial peptides, with a subsequent preliminary assessment of the minimum inhibitory concentration of multidrug-resistant bacteria. The secondary objective is to evaluate the safety of the conjugated compound and assess its viability for in vivo use. Methods The proposal involves 3 stages. First, WLBU2C, a modified version of the antimicrobial peptide WLBU2 with an added cysteine group, needs to be synthesized using a standard Fmoc procedure. It can then be stably conjugated with AgNPs ideally through photochemical means. Second, the WLBU2C-AgNP conjugate should be tested for antimicrobial activity according to the Clinical & Laboratory Standards Institute manual on standard minimum inhibitory concentration testing. Third, the cytotoxicity of the conjugate should be tested using cell lysis assays if the above stages are completed. Results I-TASSER (iterative threading assembly refinement) simulation revealed that the modified peptide WLBU2C has a secondary structure similar to that of the original WLBU2 peptide. No other results have been obtained at this time. Conclusions The addition of AgNPs to already developed de novo–engineered antimicrobial peptides provides an opportunity for the development of potent antimicrobials. Future prospects include emergency last-line therapy and treatment for current difficult-to-eradicate bacterial colonization, such as in cystic fibrosis, implantable medical devices, cancer, and immunotherapy. As I do not anticipate funding at this time, I hope this proposal provides inspiration to other researchers. International Registered Report Identifier (IRRID) PRR1-10.2196/28307
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Moser, Christian, Daniel J. Weiner, Elena Lysenko, Robert Bals, Jeffrey N. Weiser, and James M. Wilson. "β-Defensin 1 Contributes to Pulmonary Innate Immunity in Mice." Infection and Immunity 70, no. 6 (June 2002): 3068–72. http://dx.doi.org/10.1128/iai.70.6.3068-3072.2002.

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ABSTRACT Innate immunity serves as a first line defense in vertebrate organisms by providing an initial barrier to microorganisms and triggering antigen-specific responses. Antimicrobial peptides are thought to be effectors of innate immunity through their antibiotic activity and direct killing of microorganisms. Evidence to support this hypothesis in vertebrates is indirect, based on expression profiles and in vitro assays using purified peptides. Here we investigated the function of antimicrobial peptides in vivo using mice deficient in an antimicrobial peptide, mouse β-defensin-1 (mBD-1). We find that loss of mBD-1 results in delayed clearance of Haemophilus influenzae from lung. These data demonstrate directly that antimicrobial peptides of vertebrates provide an initial block to bacteria at epithelial surfaces.
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Yeaman, Michael R., Kimberly D. Gank, Arnold S. Bayer, and Eric P. Brass. "Synthetic Peptides That Exert Antimicrobial Activities in Whole Blood and Blood-Derived Matrices." Antimicrobial Agents and Chemotherapy 46, no. 12 (December 2002): 3883–91. http://dx.doi.org/10.1128/aac.46.12.3883-3891.2002.

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ABSTRACT Peptides that exert antimicrobial activity in artificial media may lack activity within blood or other complex biological matrices. To facilitate the evaluation of antimicrobial peptides for possible therapeutic utility, an ex vivo assay was developed to assess the extent and durability of peptide antimicrobial activities in complex fluid biomatrices of whole blood, plasma, and serum compared with those in conventional media. Novel antimicrobial peptides (RP-1 and RP-11) were designed based in part on platelet microbicidal proteins. RP-1, RP-11, or gentamicin was introduced into biomatrices either coincident with, or 2 h prior to, inoculation with an Escherichia coli target organism. Antimicrobial activities of peptides were assessed by quantitative culture 2 h after bacterial inoculation and compared to those of peptide-free and gentamicin controls. In whole blood and homologous plasma or serum, introduction of RP-1 or RP-11 coincident with E. coli was associated with a significant reduction in CFU per milliliter versus the respective peptide-free controls. Moreover, substantial antimicrobial activity remained when RP-1 or RP-11 was placed into whole blood or plasma 2 h prior to E. coli inoculation. These results suggest that the peptides were not rapidly inactivated within these biomatrices. Peptide antimicrobial activities were negatively affected by preincubation in serum or in heat-inactivated serum, compared with those of the respective controls. Peptides RP-1 and RP-11 were consistently effective at lower concentrations in biomatrices than in artificial media, indicating favorable antimicrobial interactions with components of blood or blood fractions. Collectively, these findings support the concept that synthetic peptides can be designed to exert potent antimicrobial activities in relevant and complex biological matrices.
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Bhargavi Ram, Thimmiah, Chien Chien Belinda Tang, Siaw Fui Kiew, Sie Yon Lau, Gobi Gobi, Jeevanandam Jaison, and Michael K. Danquah. "Nanoformulation of Peptides for Pharmaceutical Applications: In Vitro and In Vivo Perspectives." Applied Sciences 12, no. 24 (December 13, 2022): 12777. http://dx.doi.org/10.3390/app122412777.

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Peptides are short sequences of proteins consisting of two or more amino acids that are linked by peptide bonds. Peptide-based designs and drug deliveries can offer several advantages, such as antioxidant, antimicrobial, antihypertensive activities, along with immunomodulatory and antithrombotic properties, with hormone or drug-like potential. Peptide-based therapeutic formulations are used as drug candidates for the treatment of various diseases. However, there are several concerns associated with the efficacy of peptides in pharmaceutical design and delivery, including rapid degradation, limited solubility, and poor permeability. The nanoformulation of peptides has been identified as a promising approach for improving the stability of peptides and providing metabolic stability and bioavailability. This article provides an overview of the advances in the development of peptides for drug design and formulation applications. It discusses various peptide nanoformulation approaches as well as recent developments in the in vitro and in vivo analyses of nanoformulated peptides for pharmaceutical applications.
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Boullet, Héloise, Fayçal Bentot, Arnaud Hequet, Carine Ganem-Elbaz, Chérine Bechara, Emeline Pacreau, Pierre Launay, et al. "Small AntiMicrobial Peptide with In Vivo Activity Against Sepsis." Molecules 24, no. 9 (May 1, 2019): 1702. http://dx.doi.org/10.3390/molecules24091702.

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Antimicrobial peptides (AMPs) are considered as potential therapeutic sources of future antibiotics because of their broad-spectrum activities and alternative mechanisms of action compared to conventional antibiotics. Although AMPs present considerable advantages over conventional antibiotics, their clinical and commercial development still have some limitations, because of their potential toxicity, susceptibility to proteases, and high cost of production. To overcome these drawbacks, the use of peptides mimics is anticipated to avoid the proteolysis, while the identification of minimalist peptide sequences retaining antimicrobial activities could bring a solution for the cost issue. We describe here new polycationic -amino acids combining these two properties, that we used to design small dipeptides that appeared to be active against Gram-positive and Gram-negative bacteria, selective against prokaryotic versus mammalian cells, and highly stable in human plasma. Moreover, the in vivo data activity obtained in septic mice reveals that the bacterial killing effect allows the control of the infection and increases the survival rate of cecal ligature and puncture (CLP)-treated mice.
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Zhang, Lijuan, Jody Parente, Scott M. Harris, Donald E. Woods, Robert E. W. Hancock, and Timothy J. Falla. "Antimicrobial Peptide Therapeutics for Cystic Fibrosis." Antimicrobial Agents and Chemotherapy 49, no. 7 (July 2005): 2921–27. http://dx.doi.org/10.1128/aac.49.7.2921-2927.2005.

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ABSTRACT Greater than 90% of lung infections in cystic fibrosis (CF) patients are caused by Pseudomonas aeruginosa, and the majority of these patients subsequently die from lung damage. Current therapies are either targeted at reducing obstruction, reducing inflammation, or reducing infection. To identify potential therapeutic agents for the CF lung, 150 antimicrobial peptides consisting of three distinct structural classes were screened against mucoid and multidrug-resistant clinical isolates of P. aeruginosa, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, and Staphylococcus aureus. Five peptides that retained potent antimicrobial activities in physiological salt and divalent cation environment were further characterized in vivo using a rat chronic lung infection model. All animals were inoculated intratracheally with 104 P. aeruginosa mucoid PAO1 cells in agar beads. Three days following inoculation treatment was initiated. Animals were treated daily for 3 days with 100 μl of peptide solution (1 mg/ml) in 10 mM sodium citrate, which was deposited via either intratracheal instillation or aerosolization. Control animals received daily exposure to vehicle alone. At the end of the treatment the lungs of the animals were removed for quantitative culture. Four peptides, HBCM2, HBCM3, HBCPα-2, and HB71, demonstrated significant reduction in Pseudomonas bioburden in the lung of rats. Further in vivo studies provided direct evidence that anti-inflammatory activity was associated with three of these peptides. Therefore, small bioactive peptides have the potential to attack two of the components responsible for the progression of lung damage in the CF disease: infection and inflammation.
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Rodrigues, Elaine G., Andrey S. Dobroff, Carlos P. Taborda, and Luiz R. Travassos. "Antifungal and antitumor models of bioactive protective peptides." Anais da Academia Brasileira de Ciências 81, no. 3 (September 2009): 503–20. http://dx.doi.org/10.1590/s0001-37652009000300015.

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Peptides are remarkably reactive molecules produced by a great variety of species and able to display a number of functions in uni-and multicellular organisms as mediators, agonists and regulating substances. Some of them exert cytotoxic effects on cells other than those that produced them, and may have a role in controlling subpopulations and protecting certain species or cell types. Presently, we focus on antifungal and antitumor peptides and discuss a few models in which specific sequences and structures exerted direct inhibitory effects or stimulated a protective immune response. The killer peptide, deduced from an antiidiotypic antibody, with several antimicrobial activities and other Ig-derived peptides with cytotoxic activities including antitumor effects, are models studied in vitro and in vivo. Peptide 10 from gp43 of P. brasiliensis (P10) and the vaccine perspective against paracoccidioidomycosis is another topic illustrating the protective effect in vivo against a pathogenic fungus. The cationic antimicrobial peptides with antitumor activities are mostly reviewed here. Local treatment of murine melanoma by the peptide gomesin is another model studied at the Experimental Oncology Unit of UNIFESP.
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Dissertations / Theses on the topic "Antimicrobial PEPTIDES IN VIVO"

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Waldbrook, Matthew George. "In vivo efficacy of novel antibacterial and immunomodulatory peptides." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2850.

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Despite the success of modern medicine in treating infections, infectious diseases remain a major source of morbidity and mortality worldwide. The evolution of antibiotic resistant strains of bacteria means that new innovations in therapeutics must be pursued to combat this emerging threat. A novel approach is to utilize the anti-infective properties of endogenous host defense peptides by creating smaller synthetic peptides with enhanced protective activities. Some of these peptides directly kill bacteria and many display varied immunomodulatory activities, enhancing the host innate immune response to more effectively clear an infection. Here I examined the efficacy of several synthetic peptides in a murine model of invasive bacterial infection, induced by the Gram positive bacterium Staphylococcus aureus. Several peptides were able to significantly reduce peritoneal bacterial load in vivo by up to 4-logs relative to the controls, either through direct antibacterial killing or immunomodulatory activity. The latter class was studied in more detail; in particular, the peptides IDR-1 and 1002 displayed significant immunomodulatory effects in vivo. Both peptides were able to significantly induce the proinflammatory chemokines MCP-1, RANTES and KC, as well as increased recruitment of neutrophils and monocytes to the site of infection. These effects were not dependent on live bacteria, as heat inactivated S. aureus was also able to induce chemokines and cell migration. Mice that had been depleted of macrophages did not respond to peptide treatment, indicating that macrophages are an important effector cells through which immunomodulatory peptides counter infections. These results suggest that synthetic peptides have the potential to become a viable treatment option for bacterial infections.
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Pelillo, Chiara. "Therapeutic potential of BAC7(I-35), a Proline-rich Antimicrobial Peptide: in vitro and in vivo studies and Pegylation strategy to improve its bioavailability." Doctoral thesis, Università degli studi di Trieste, 2011. http://hdl.handle.net/10077/5978.

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2009/2010
The antimicrobial peptides (AMPs) are an important component of the innate defense against invading microorganisms, are widespread in nature and may have multiple and diversified mechanisms of bactericidal action. In addition to their direct antimicrobial activity the are also involved in other biological processes. The aim of this project was to investigate the in vivo activity of Bac7(1-35), a bovine proline-rich antimicrobial peptide, having in mind its possible use as a lead compound for the development of novel anti-infective agents. Before moving to animal models of infection, the in vitro stability of the peptide in the presence of murine and human serum or plasma as well as its biodistribution in mouse were investigated. Antibacterial activity assays against Salmonella enterica showed that the presence of murine blood components largely inhibits the antibacterial activity of the peptide. On the contrary, in human serum and plasma Bac7(1-35) maintains its efficacy. This is due to the more rapid degradation by proteases of murine blood. The in vivo biodistribution of Bac7(1-35) was investigated by using a time-domain optical imaging apparatus and a fluorescently-labeled Bac7(1-35) derivative. The compound reaches the kidney and the bladder respectively 1 and 3 hours after i.p. injection. The in vivo and ex vivo analyses performed after 24 h confirm that the compound has been totally excreted. A mouse model of S. typhimurium infection was set up and used to test the therapeutic efficacy of Bac7(1-35). Treatment of infected mice with the peptide injected i.p. immediately after a lethal, intraperithoneal bacterial challenge, increased the mean survival time and reduced significantly the number of viable bacterial cells in liver and spleen of treated mice at 3 days post-inoculum. In 1/3 of the organ homogenates, the bacterial presence was undetectable and this result matches the percentage of cured animals (35%). In an attempt to improve its pharmacokinetic profile, the peptide was conjugated with polyethylene glycol (PEG), a non-toxic, non-immunogenic and FDA-approved polymer. Different strategies of pegylation have been considered to find the best method in terms of chemical yield and of maintenance of biological activity. Pegylation via a thioether ligation resulted the best strategy to obtain a slow active peptide release in human blood components with a reduced renal clearance and an increased bioavailability of Bac7(1-35), as biodistribution analyses demonstrated. Several important pathogens, such as S. enterica, cause disease by surviving and replicating within host cells. Since many AMPs have also immunomodulatory activities, we investigated the effect of Bac7(1-35) on the interaction between macrophages and Salmonella. We carried out phagocytosis assays with macrophages and the results suggest that Bac7(1-35) plays a positive modulatory effect on this function. Phagocytosis assays were also performed to determine if Bac7(1-35) could inhibit survival and replication of intracellular Salmonella. The results show that the peptide inhibits the replication of intracellular Salmonella, suggesting that it can exert its antibacterial activity within eukaryotic cells. Further studies are required to fully understand the details of the Bac7(1-35) biological activities. The results obtained provide encouraging evidence for future investigations on Bac7(1-35) and on the pegylated form Bac7(1-35)CAM-PEG20k also in other models of infection and with different intracellular pathogens.
XXIII Ciclo
1981
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Silva, Osmar Nascimento. "Avaliação do potencial terapêutico e estudo da atividade imunomodulatória e antimicrobiana in vitro e in vivo de diferentes formas de clavaninas." Universidade Federal de Juiz de Fora (UFJF), 2010. https://repositorio.ufjf.br/jspui/handle/ufjf/4272.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
As infecções relacionadas à assistência à saúde (IrAS), são uma das principais causas de mortalidade e aumento dos custos hospitalares em países desenvolvidos e em desenvolvimento. Nos casos em que um paciente adquire uma IrA e esta não é tratada adequadamente, a mesma pode evoluir para um quadro mais grave, podendo levar a sepse e consequentemente na maioria dos casos a morte. A sepse representa um importante problema de saúde pública, entretanto, um tratamento eficaz para esta síndrome ainda não foi encontrado. Peptídeos antimicrobianos foram relatados para modular a resposta à infecção bacteriana na sepse, independente dos mecanismos de resistência conhecidos para os antibióticos. Desta forma, procurou-se investigar a atividade imunomodulatória de duas formas de clavaninas sobre monócitos RAW 264.7, bem como a atividade antimicrobiana e a citotoxicidade in vitro. Em ensaios in vivo a genotoxicidade, a ação das clavaninas sobre a migração de neutrófilos e a eficácia do tratamento com as clavaninas em um modelo de infecção de ferida operatória por S. aureus e sepse polimicrobiana grave também foram avaliadas. Os estudos in vitro demostraram que as clavaninas inibiram completamente o crescimento de E. coli, K. pneumoniae e S. aureus, preveniram a secreção de citocinas pró-inflamatórias (TNF-α, IL-12) e NO, e aumentaram a secreção de IL-10. Além disso, as clavaninas não apresentaram atividade citotóxica sobre as células RAW 264.7. Nos experimentos in vivo, as clavaninas não apresentaram genotoxicidade, além de apresentarem-se quimoatraentes para neutrófilos. As clavaninas, também, reduziram significativamente as unidades formadoras de colônias de S. aureus no modelo experimental de ferida operatória, e reduziram a mortalidade dos animais sépticos em mais de 50%, quando comparados com animais controle. Devido à sua ação direta sobre células do sistema imune e microorganismos, as clavaninas aparentam ser compostos potenciais para o tratamento de infecções bacterianas graves como a sepse, demonstrando alto valor biotecnológico.
Healthcare-associated infections (HAIs) are a major cause of mortality, also increasing hospital costs in developed and developing countries. When a patient acquires HAIs and this is not properly handled, disease may clearly worst, leading to sepsis and consequently in major to death. Despite of sepsis represents an important public health problem, any effective treatment for this syndrome was obtained until now. In this view, antimicrobial peptides have been reported as modulators of immune response to bacterial infection in sepsis, with independent activity of mechanisms that lead to antibiotic. Thus, the immunomodulatory activity of two different forms of clavanins over RAW 264.7 monocytes, as well the in vitro antimicrobial and cytotoxic activities were here investigated. Furthermore, in vivo genotoxicity assays, the evaluation of clavanins activity on neutrophil migration and also the efficacy of treatment with clavanins in a wound S. aureus infection model and severe polymicrobial sepsis were also evaluated. Moreover, in vitro studies demonstrated that clavanins are able of inhibit the growth of E. coli, K. pneumoniae and S. aureus. Clavanins also prevented the secretion of proinflammatory cytokines (TNF-α, IL-12) and NO, and increased the IL-10secretion. In addition, clavanins showed none cytotoxicity on RAW 264.7 cells. During in vivo experiments, the clavanins showed no genotoxicity, showing however, a clear chemotactic effect for neutrophils. Clavanins also significantly reduced the colony-forming units of S. aureus in an experimental model of surgical wound infection and reduced the mortality of septic animals in more than 50 %, when compared to control group. Due to their direct activities over immune cells and microorganisms, clavanins are potential compounds for the treatment of serious bacterial infections such as sepsis, showing an enormous and remarkable biotechnological value.
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Bürkle, Carl-Philipp Stavros. "Die Expression antimikrobieller Peptide (Psoriasin, HBD-2 und HBD-3) in menschlicher Haut und deren Modulation in vivo - eine Untersuchung im xenogenen Haut-Transplantationsmodell." Doctoral thesis, Universitätsbibliothek Leipzig, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-73827.

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In der humanen Haut spielen antimikrobielle Peptide (AP) bei Entzündungsgeschehen bakteriellen und nicht-bakteriellen Ursprungs eine bedeutende Rolle. Neben einer konstitutiven Expression AP können Zytokine deren vermehrte oder abgeschwächte Expression bewirken. In dieser Arbeit wurden die AP humanes β-Defensin (HBD) -2, HBD-3 und Psoriasin (PSO) in Bezug auf deren Expression in gesunder Haut und deren Modulation durch Zytokine in vivo anhand des xenogenen NOD-SCID-Maus-Transplantationsmodells untersucht. Nach erfolgreicher Transplantation von humaner Haut auf NOD-SCID Mäuse wurden die Zytokine TNF-α, IFN-γ und IL-13 in unterschiedlicher Dosierung einzeln und in Kombination intradermal appliziert. Für TNF-α konnte eine erhöhte Expression von HBD-2, HBD-3 und PSO auf RNA-Ebene mittels in-situ-Hybridisierung und Protein-Ebene mittels immunhistochemischer Nachweismethoden gezeigt werden. Eine erhöhte Expression nach Injektion von IFN-γ ließ sich für HBD-3 auf RNA-Ebene und Protein-Ebene und für HBD-2 auf RNA-Ebene erfolgreich belegen. PSO zeigte auf Protein-Ebene nach Modulation mit IFN-γ eine bei höherer Dosierung leicht abnehmende Expression. Eine Änderung der Expression durch IL-13 ließ sich nicht eindeutig belegen. In dieser Arbeit konnte die in der Literatur in vitro beschriebene Modulationsfähigkeit der untersuchten AP durch die verwendeten Zytokine in vivo belegt werden.
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Borrelli, Alexander P. "Synthetic Genes for Antimicrobial Peptides." Digital WPI, 2003. https://digitalcommons.wpi.edu/etd-theses/427.

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The goal of this project was to clone and express the antimicrobial peptide protegrin 1 (PG-1). Initially a yeast system was chosen but was discarded due to technical difficulties. Invitrogen's bacterial T7 expression system was chosen next to express the peptide. PG-1 expression was verified by anti-his immunoblot and then the peptide was purified by IMAC. Its activity was verified using a Bacillus subtillis radial diffusion assay.
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Borelli, Alexander P. "Synthetic genes for antimicrobial peptides." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0428103-102059/.

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Vaucher, Rodrigo de Almeida. "Influência do peptídeo P34 na expressão gênica em Listeria spp. e estudo da citotoxicidade dos peptídeos P34 e P40." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/23977.

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Neste estudo foram realizados inicialmente, experimentos para avaliar a ação sinérgica do peptídeo antimicrobiano P34 com sobrenadantes de culturas de algumas bactérias lácticas selecionadas e isoladas de queijo Minas Frescal. Foi investigada a influência deste peptídeo na expressão de genes em L. monocytogenes e L. seeligeri, sua citotoxicidade em diferentes células eucarióticas e toxicidade “in vivo”. Também foram realizados alguns testes para avaliar a citotoxicidade do peptídeo antimicrobiano P40. A adição do peptídeo P34 no queijo provocou uma diminuição de até 3 ciclos logarítmicos na contagem de células viáveis de L. monocytogenes inoculada artificialmente. Um aumento significativo na expressão dos genes dltA, Imo 1695 e mptA de L. monocytogenes foi observado após 96 h com a presença do peptídeo P34 no queijo. A influência do peptídeo P34 na expressão de genes associados aos componentes do envelope celular de L. monocytogenes e L. seeligeri, promoveu um aumento não significativo nos níveis de transcrição de genes dltA, Imo1695 e mptA observados em L. monocytogenes após inoculação em placas e incubação por 24 h a 37°C ou 240 h a 4°C. Em L. seeligeri uma diminuição significativa na expressão do gene dltA foi observada. Os genes Imo1695 e mptA demonstraram uma diminuição significativa de sua expressão (2000 e 31872 vezes, respectivamente) na presença do peptídeo P34 e incubação por 24 h a 37°C. A inoculação da placa com o peptídeo P34 e incubação por 240 h a 4ºC não promoveu diminuição significativa da expressão do gene mptA. A citotoxicidade dos peptídeos P34 e P40 foi avaliada em células VERO, tratadas com diferentes concentrações (0,02 - 2,5 μg ml-1). Nos ensaios de MTT, NRU e LDH as EC50 para o peptídeo P34 foram 0.60, 1.25, 0.65 μg ml-1 e do peptídeo P40 foram 0,30, 0,51 e 0,57 μg ml-1, respectivamente. A atividade hemolítica em eritrócitos humanos foi de (5,8%) e (19%), respectivamente. Os efeitos sobre a viabilidade, motilidade e exocitose acrossomal de espermatozóides humanos também foram avaliadas para o peptídeo P34. Não houve reações de hipersensibilidade ou aumento significativo de títulos de anticorpos durante os experimentos imunogenicidade ou morte dos animais durante experimentos de toxicidade aguda ou subcrônica. A DL50 foi superior a 332,3 ± 0,76 mg/kg. Não foram observadas alterações significativas nos parâmetros bioquímicos séricos nos animais tratados com o peptídeo P34. Não foram detectados sinais de possível toxicidade nos animais do grupo tratado com 0,825 mg/ kg/dia do peptídeo P34. Neste grupo apenas alterações histológicas no baço com a presença de megacariócitos foram observadas. A partir destes resultados evidencia-se o potencial do peptídeo P34 para ser utilizado como bioconservante em alimentos.
In this study initial experiments were performed to evaluate synergistic action of the antimicrobial peptide P34 and culture supernatants of some selected lactic acid bacteria isolated from Minas Frescal cheese. The influence of this peptide in the expression of genes in L. monocytogenes and L. seeligeri, their cytotoxicity in differents eukaryotic cells and “in vivo” toxicity was investigated. Also, some tests were carried out o evaluate the cytotoxicity of the antimicrobial peptide P40. The peptide P34 caused a decrease of up to 3 log cycles in viable counts of L. monocytogenes artificially inoculated in cheese. A significant increase in expression of genes dltA, Imo1695 mptA of L. monocytogenes was observed after 96 h incubation of the peptide P34 in cheese. The influence of peptide P34 on the expression of genes associated to components of cell envelope of L. monocytogenes and L. seeligeri, promoted a non significant increase in the levels of transcription of genes dltA, Imo1695 and mptA were observed after incubation of L. monocytogenes for 24 hs at 37°C and 240 hs at 4°C in plates. In L. seeligeri a significant decrease was observed in gene expression dltA. The gene Imo1695 showed a significant decrease in its expression (2000-fold) after inoculation with the peptide P34. A significant decrease of expression was also observed for the gene mptA (31872 - times) after inoculation with the peptide P34 and incubation for 24 hours at 37°C. The inoculation of the plate with the P34 peptide and incubated for 240 hrs at 4°C, showed a non-significant decrease of gene expression. The cytotoxicity of the peptide P34 and P40 was assessed in VERO cells treated with different concentrations (0.02 - 2.5 μg ml- 1). In MTT, NRU and LDH assays the EC50 to the peptide P34 were 0.60, 1.25, 0.65 μg ml-1 and the peptide P40 were 0.30, 0.51 and 0.57 μg ml-1, respectively. The hemolytical activity on human erythrocytes was of (5.8%) and (19%), respectively. The effects on viability, motility and acrosomal exocytosis of humam sperm were also evaluated for peptideP34. There were no hypersensitivity reactions or significant increase in antibody titer during the immunogenicity experiment or death of animals during the acute or subchronic toxicity tests. The LD50 was more the 332.3 ± 0.76 mg/kg. No significant changes in the serum biochemical parameters were observed in the animals treated with the peptide P34. Signs of possible toxicity were no detected in animals in the group treated with 0.825 mg/kg day of peptide P34. In this group only histological changes in the spleen with the presence of megakaryocytes were observed. From these results show the potential o peptide P34 to be used in future as biopreservative in foods.
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Vargues, Thomas. "Antimicrobial peptides : structure, function and resistance." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4076.

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Higher eukaryotes produce a vast range of antimicrobial peptides (AMPs) that play important roles in their defence against microbial infection. Beta defensins are small (3-5 kDa), cationic peptides that display broad, potent antimicrobial activity against a range of microbes and also act as chemoattractants of important immunomodulatory cells. To generate highly pure peptides for structural and functional studies, we developed a method to prepare recombinant human beta defensin-2 (HBD2). The HBD2 gene was synthesised by recursive PCR with codons optimised for expression in Escherichia coli. HBD2 was expressed as an insoluble fusion to a His-tagged ketosteroid isomerase. After cleavage from the fusion with cyanogen bromide, 1H NMR spectroscopy and mass spectrometry confirmed that the oxidised HBD2 was folded and possessed the correct b-defensin disulfide bond topology. The recombinant HBD2 was active against E. coli, P. aeruginosa, S. aureus and C. albicans and was also a chemoattractant against HEK293 cells expressing the chemokine receptor CCR6. 15N-labelled HBD2 was also prepared and was highly suitable for future structural studies. Since defensins are thought to interact with bacterial membranes we also tested the recombinant HBD2 in biophysical studies (surface plasmon resonance, SPR, Biacore). We observed different binding to artificial model membranes containing either E. coli Kdo2-lipid A or phospholipids. Bacterial resistance to AMPs has been linked to the covalent modification of the outer membrane lipid A by 4-amino-4-deoxy-L-arabinose (L-Ara4N). This neutralises the charge of the LPS, thereby decreasing the electrostatic attraction of cationic peptides to the bacterial membrane. The pathogen Burkholderia cenocepacia displays extremely high resistance to AMPs and other antibiotics and the Ara4N pathway appears to be essential. To explore this further we expressed recombinant forms of two enzymes (ArnB and ArnG) from the B. cenocepacia Ara4N pathway. Purified ArnB is a pyridoxal 5’-phosphate (PLP)-dependent transaminase and we tested its ability to bind amino acid substrates. We investigated the binding of inhibitors L- and D-cycloserine to ArnB and tested their antibiotic activity against Burkholderia strains. We also studied the B. cenocepacia ArnG – a proposed membrane protein undecaprenyl-L-Ara4N flippase – and showed that the protein behaved as a dimer by non-denaturing gel analysis. The B. cenocepacia ArnG failed to complement E. coli knock-out strains encoding the equivalent flippase proteins ArnE and ArnF, suggesting that ArnG is a Burkholderia-specific protein.
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Zhao, Hongxia. "Mode of action of antimicrobial peptides." Helsinki : University of Helsinki, 2003. http://ethesis.helsinki.fi/julkaisut/laa/biola/vk/zhao/.

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Parisi, Rosaura. "Computational design of new antimicrobial peptides." Doctoral thesis, Universita degli studi di Salerno, 2018. http://hdl.handle.net/10556/3018.

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2016 - 2017
Antimicrobial peptides (AMP) are evolutionarily conserved components of the innate immune system. They have a broad spectrum of action against bacteria, fungi and viruses. Therefore, AMP are studied as probable substitutes of the traditional antibiotics, for which most pathogens have developed resistance. The main objective of this work was the design of novel linear peptides capable to interact with the cellular membrane of the common pathogens. In this work, sequences of active AMP were carefully obtained from the scientific literature and collected in Yadamp (http://yadamp.unisa.it/), a database of AMP created recently in the laboratory where this project was carried out. In Yadamp, there are information about peptides name, amino acid sequence, length, presence of disulfide bridges, date of discovery, activity and taxonomy. The most relevant chemical-physical properties are also listed. This database is mainly focused on the peptides activities. Experimental MIC values (the lowest concentration of an antimicrobial that inhibits the visible growth of a microorganism) are constantly obtained from careful reading the original papers. In this work, a great contribution was made in the enrichment of the database. In fact, 1009 sequences were added to Yadamp. It currently contains 3142 AMP sequences. For these AMP, 573 molecular descriptors were calculated. In addition, this project also involved the search for new molecular descriptors. Yadamp is a resource for QSAR investigations on AMP. It allows to create subsets of AMP, homogeneous in one, two or more parameters...[abstract by Author]
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Books on the topic "Antimicrobial PEPTIDES IN VIVO"

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Hansen, Paul R., ed. Antimicrobial Peptides. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-6737-7.

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Matsuzaki, Katsumi, ed. Antimicrobial Peptides. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-3588-4.

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Phoenix, David A., Sarah R. Dennison, and Frederick Harris. Antimicrobial Peptides. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527652853.

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Giuliani, Andrea, and Andrea C. Rinaldi, eds. Antimicrobial Peptides. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-594-1.

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Harder, Jürgen, and Jens-M. Schröder, eds. Antimicrobial Peptides. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-24199-9.

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Joan, Marsh, Goode Jamie, Ciba Foundation, and Symposium on Antimicrobial Peptides (1994 : Ciba Foundation)d), eds. Antimicrobial peptides. Chichester, Eng: Wiley, 1994.

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Drider, Djamel, and Sylvie Rebuffat, eds. Prokaryotic Antimicrobial Peptides. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-7692-5.

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Hiemstra, Pieter S., and Sebastian A. J. Zaat, eds. Antimicrobial Peptides and Innate Immunity. Basel: Springer Basel, 2013. http://dx.doi.org/10.1007/978-3-0348-0541-4.

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Shafer, William M., ed. Antimicrobial Peptides and Human Disease. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/3-540-29916-5.

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Antimicrobial peptides: Methods and protocols. New York: Humana Press/Springer, 2010.

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Book chapters on the topic "Antimicrobial PEPTIDES IN VIVO"

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Afacan, Nicole J., Laure M. Janot, and Robert E. W. Hancock. "Host Defense Peptides: Immune Modulation and Antimicrobial Activity In Vivo." In Antimicrobial Peptides and Innate Immunity, 321–58. Basel: Springer Basel, 2012. http://dx.doi.org/10.1007/978-3-0348-0541-4_13.

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Kolar, Satya Sree, Hasna Baidouri, Maria Luisa Mangoni, and Alison M. McDermott. "Methods for In Vivo/Ex Vivo Analysis of Antimicrobial Peptides in Bacterial Keratitis: siRNA Knockdown, Colony Counts, Myeloperoxidase, Immunostaining, and RT-PCR Assays." In Methods in Molecular Biology, 411–25. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-6737-7_30.

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Park, Andrew J., Jean-Phillip Okhovat, and Jenny Kim. "Antimicrobial Peptides." In Clinical and Basic Immunodermatology, 81–95. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-29785-9_6.

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Chakraborti, Srinjoy, and Sanjay Ram. "Antimicrobial Peptides." In Management of Infections in the Immunocompromised Host, 95–113. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-77674-3_5.

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Marcos, Jose F., and Paloma Manzanares. "Antimicrobial Peptides." In Antimicrobial Polymers, 195–225. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9781118150887.ch8.

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Jack, Ralph W., Gabriele Bierbaum, and Hans-Georg Sahl. "Antimicrobial Peptides." In Lantibiotics and Related Peptides, 1–39. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-662-08239-3_1.

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Lata, Sneh, and Gajendra Raghava. "Antimicrobial Peptides." In Encyclopedia of Systems Biology, 31–33. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4419-9863-7_87.

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Ganz, T., and R. I. Lehrer. "Antimicrobial Peptides." In Handbook of Experimental Pharmacology, 295–304. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55742-2_16.

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Sørensen, Ole E. "Antimicrobial Peptides in Cutaneous Wound Healing." In Antimicrobial Peptides, 1–15. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-24199-9_1.

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Zasloff, Michael. "Antimicrobial Peptides: Do They Have a Future as Therapeutics?" In Antimicrobial Peptides, 147–54. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-24199-9_10.

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Conference papers on the topic "Antimicrobial PEPTIDES IN VIVO"

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Kašperová, Alena, Jaroslav Turánek, Václav Čeřovský, and Milan Raška. "In vitro and in vivo antimicrobial effect of lasioglossins on the Candida albicans." In XIIth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2011. http://dx.doi.org/10.1135/css201113054.

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Tůmová, Tereza, Petra Lovecká, Václav Čeřovský, and Jiřina Slaninová. "Real time in vivo monitoring of cytotoxic activity of two different antimicrobial peptides lasioglossin III and lasiocepsin." In XIIth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2011. http://dx.doi.org/10.1135/css201113151.

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Lammi, Carmen. "From the bench to the bedside: the history of lupin bioactive peptides as useful ingredient for the prevention of metabolic syndrome." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/bwgm4089.

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Proteins derived from lupin seeds are gaining attention as a source of bioactive peptides. In fact, several pieces of evidence highlight the biological activities of lupin protein hydrolysates and peptides, including hypocholesterolemic, hypoglycemic, antimicrobial, anti-inflammatory, and immunomodulatory effects. The health-promoting activities of lupin peptides have been tested in different animal models and clinical trials. Briefly, diets containing protein from L. albus or L. angustifolius significantly reduce both total cholesterol and low-density lipoprotein (LDL) cholesterol (LDL-C) levels versus control diets containing casein in a rat or hamster models of hypercholesterolemia. An uncontrolled clinical trial on L. albus and two controlled ones on L. angustifolius have confirmed the hypocholesterolemic activity in humans. In light with these evidences and with a more updated perception of the phenomenon, our study suggests that the observed health-promoting activity does not lie in the native protein, but the mixture of peptides generated from the physiological hydrolysis of proteins during digestion. Indeed, many efforts have been pursued in order to characterize the molecular mechanism through which lupin hydrolysates, obtained different hydrolytic enzymes, exert hypocholesterolemic and anti-diabetic effects in vitro and in vivo. In this context, specific peptides responsible of the biological activity exerted by the peptide mixture were also identified and fully characterized from chemical and biological point of view. Doubtless, our results highlight that lupin hydrolysates may be exploited as new ingredients for the development of dietary supplements or functional foods
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Krasnodembskaya, Anna, Yuanlin Song, Jae-Woo Lee, and Michael A. Matthay. "Human Mesenchymal Stem Cells Exert Antimicrobial Activity In Vitro And In Vivo In Part Through The Secretion Of The Antimicrobial Peptide LL-37." In American Thoracic Society 2011 International Conference, May 13-18, 2011 • Denver Colorado. American Thoracic Society, 2011. http://dx.doi.org/10.1164/ajrccm-conference.2011.183.1_meetingabstracts.a1246.

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Turánek, Jaroslav, Michaela Škrabalová, and Pavlína Knötigová. "Antimicrobial and anticancer peptides." In XIth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2009. http://dx.doi.org/10.1135/css200911128.

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Kaygorodova, I. A. "ANTIMICROBIAL PEPTIDES OF PARASITIC LEECHES." In ECOLOGICAL PROBLEMS OF LAKE BAIKAL BASIN. Buryat Scientific Center of SB RAS Press, 2022. http://dx.doi.org/10.31554/978-5-7925-0621-3-2022-59-61.

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Čeřovský, Václav, Rudolf Ježek, Vladimír Fučík, and Jiřina Slaninová. "Antimicrobial peptides from the venom of Vespidae." In Xth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2007. http://dx.doi.org/10.1135/css200709025.

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Doležílková, Ivana, Martina Macková, and Tomáš Macek. "Short peptides with antimicrobial activity from plants." In XIth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2009. http://dx.doi.org/10.1135/css200911025.

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Ehala, Sille, Petr Niederhafner, Václav Čeřovský, Pavel Řezanka, David Sýkora, Vladimír Král, and Václav Kašička. "Analysis of antimicrobial peptides by capillary electrophoresis." In XIIth Conference Biologically Active Peptides. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2011. http://dx.doi.org/10.1135/css201113037.

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Bo, Shi-ru, Jiang-hua Yu, Ya-li Wang, and Quan-kai Wang. "Preparation and Antimicrobial Activity of Antimicrobial Peptides from Plum Deer Antler." In 2017 5th International Conference on Mechatronics, Materials, Chemistry and Computer Engineering (ICMMCCE 2017). Paris, France: Atlantis Press, 2017. http://dx.doi.org/10.2991/icmmcce-17.2017.142.

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Reports on the topic "Antimicrobial PEPTIDES IN VIVO"

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Doherty, Laurel A., Morris Slutsky, and Jason W. Soares. Antimicrobial Peptides with Differential Bacterial Binding Characteristics. Fort Belvoir, VA: Defense Technical Information Center, March 2013. http://dx.doi.org/10.21236/ada577726.

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Mierswa, S. C., T. H. Lee, and M. C. Yung. Developing an engineered therapeutic microbe to release antimicrobial peptides (AMPs). Office of Scientific and Technical Information (OSTI), August 2019. http://dx.doi.org/10.2172/1558856.

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Yung, M. C. Engineering a therapeutic microbe for site-of-infection delivery of encapsulated antimicrobial peptides (AMPs). Office of Scientific and Technical Information (OSTI), October 2019. http://dx.doi.org/10.2172/1573149.

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Vouros, Paul, and Terrance Black. Solid Phase Peptide Synthesis of Antimicrobial Peptides for cell Binding Studies: Characterization Using Mass Spectrometry. Fort Belvoir, VA: Defense Technical Information Center, November 2002. http://dx.doi.org/10.21236/ada412571.

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Noga, Edward J., Angelo Colorni, Michael G. Levy, and Ramy Avtalion. Importance of Endobiotics in Defense against Protozoan Ectoparasites of Fish. United States Department of Agriculture, September 2003. http://dx.doi.org/10.32747/2003.7586463.bard.

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Infectious disease is one of the most serious causes of economic loss in all sectors of aquaculture. There is a critical need to understand the molecular basis for protection against infectious disease so that safer, more reliable and more cost-effective strategies can be designed for their control. As part of this effort, the major goal of our BARD project was to determine the importance of endobiotics as a defense against protozoan ectoparasites in fish. Endobiotics, or antimicrobial polypeptides, are peptides and small proteins that are increasingly recognized as having a vital role in the innate defense of virtually all animals. One objective of our BARD project was to determine the antiparasitic potency of one specific group of endobiotics that were isolated from hybrid striped bass (Morone saxatilis x M chrysops). We found that these endobiotics, which we had previously named histone-like proteins (HLPs), exhibited potent activity against Amyloodinium and that the putative levels of HLPs in the skin were well within the levels that we found to be lethal to the parasite in vitro. We also found evidence for the presence of similar antibiotics in sea bream (Sparus aurata) and Mediterranean sea bass (Dicentrarchus labrax). We also examined the effect of chronic stress on the expression of HLP in fish and found that HLP levels were dramatically decreased after only one week of a crowding/high ammonia sublethal stress. We also began to explore the feasibility of upregulating endobiotics via immunostimulation. However, we did not pursue this objective as fully as we originally intended because we spent a much larger effort than originally anticipated on the last objective, the attempted isolation of novel endobiotics from hybrid striped bass. In this regard, we purified and identified four new peptide endobiotics. These endobiotics, which we have named piscidins (from "Pisces" meaning fish), have potent, broad-spectrum activity against a number of both fish and human pathogens. This includes not only parasites but also bacteria. We also demonstrated that these peptides are present in the mast cell. This was the first time that the mast cell, the most common tissue granulocyte in vertebrates, was shown to possess any type of endobiotic. This finding has important implications in explaining the possible function of mast cells in the immune response of vertebrates. In summary, the research we have accomplished in this BARD project has demonstrated that endobiotics in fish have potent activity against many serious pathogens in aquaculture and that there is considerable potential to use these compounds as stress indicators in aquaculture. There is also considerable potential to use some of these compounds in other areas of medicine, including treatment of serious infectious diseases of humans and animals.
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Altstein, Miriam, and Ronald Nachman. Rationally designed insect neuropeptide agonists and antagonists: application for the characterization of the pyrokinin/Pban mechanisms of action in insects. United States Department of Agriculture, October 2006. http://dx.doi.org/10.32747/2006.7587235.bard.

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The general objective of this BARD project focused on rationally designed insect neuropeptide (NP) agonists and antagonists, their application for the characterization of the mechanisms of action of the pyrokinin/PBAN (PK-PBAN) family and the development of biostable, bioavailable versions that can provide the basis for development of novel, environmentally-friendly pest insect control agents. The specific objectives of the study, as originally proposed, were to: (i) Test stimulatory potencies of rationally designed backbone cyclic (BBC) peptides on pheromonotropic, melanotropic, myotropic and pupariation activities; (ii) Test the inhibitory potencies of the BBC compounds on the above activities evoked either by synthetic peptides (PBAN, LPK, myotropin and pheromonotropin) or by the natural endogenous mechanism; (iii) Determine the bioavailability of the most potent BBC compounds that will be found in (ii); (iv) Design, synthesize and examine novel PK/PBAN analogs with enhanced bioavailability and receptor binding; (v) Design and synthesize ‘magic bullet’ analogs and examine their ability to selectively kill cells expressing the PK/PBAN receptor. To achieve these goals the agonistic and antagonistic activities/properties of rationally designed linear and BBC neuropeptide (NP) were thoroughly studied and the information obtained was further used for the design and synthesis of improved compounds toward the design of an insecticide prototype. The study revealed important information on the structure activity relationship (SAR) of agonistic/antagonistic peptides, including definitive identification of the orientation of the Pro residue as trans for agonist activity in 4 PK/PBANbioassays (pheromonotropic, pupariation, melanotropic, & hindgut contractile) and a PK-related CAP₂b bioassay (diuretic); indications that led to the identification of a novel scaffold to develop biostbiostable, bioavailable peptidomimetic PK/PBANagonists/antagonists. The work led to the development of an arsenal of PK/PBAN antagonists with a variety of selectivity profiles; whether between different PKbioassays, or within the same bioassay between different natural elicitors. Examples include selective and non-selective BBC and novel amphiphilic PK pheromonotropic and melanotropic antagonists some of which are capable of penetrating the moth cuticle in efficacious quantities. One of the latter analog group demonstrated unprecedented versatility in its ability to antagonize a broad spectrum of pheromonotropic elicitors. A novel, transPro mimetic motif was proposed & used to develop a strong, selective PK agonist of the melanotropic bioassay in moths. The first antagonist (pure) of PK-related CAP₂b diuresis in flies was developed using a cisPro mimetic motif; an indication that while a transPro orientation is associated with receptor agonism, a cisPro orientation is linked with an antagonist interaction. A novel, biostablePK analog, incorporating β-amino acids at key peptidase-susceptible sites, exhibited in vivo pheromonotropic activity that by far exceeded that of PBAN when applied topically. Direct analysis of neural tissue by state-of-the-art MALDI-TOF/TOF mass spectrometry was used to identify specific PK/PK-related peptides native to eight arthropod pest species [house (M. domestica), stable (S. calcitrans), horn (H. irritans) & flesh (N. bullata) flies; Southern cattle fever tick (B. microplus), European tick (I. ricinus), yellow fever mosquito (A. aegypti), & Southern Green Stink Bug (N. viridula)]; including the unprecedented identification of mass-identical Leu/Ile residues and the first identification of NPs from a tick or the CNS of Hemiptera. Evidence was obtained for the selection of Neb-PK-2 as the primary pupariation factor of the flesh fly (N. bullata) among native PK/PK-related candidates. The peptidomic techniques were also used to map the location of PK/PK-related NP in the nervous system of the model fly D. melanogaster. Knowledge of specific PK sequences can aid in the future design of species specific (or non-specific) NP agonists/antagonists. In addition, the study led to the first cloning of a PK/PBAN receptor from insect larvae (S. littoralis), providing the basis for SAR analysis for the future design of 2ⁿᵈgeneration selective and/or nonselective agonists/antagonists. Development of a microplate ligand binding assay using the PK/PBAN pheromone gland receptor was also carried out. The assay will enable screening, including high throughput, of various libraries (chemical, molecular & natural product) for the discovery of receptor specific agonists/antagonists. In summary, the body of work achieves several key milestones and brings us significantly closer to the development of novel, environmentally friendly pest insect management agents based on insect PK/PBANNPs capable of disrupting critical NP-regulated functions.
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7

Droby, Samir, Michael Wisniewski, Martin Goldway, Wojciech Janisiewicz, and Charles Wilson. Enhancement of Postharvest Biocontrol Activity of the Yeast Candida oleophila by Overexpression of Lytic Enzymes. United States Department of Agriculture, November 2003. http://dx.doi.org/10.32747/2003.7586481.bard.

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Enhancing the activity of biocontrol agents could be the most important factor in their success in controlling fruit disease and their ultimate acceptance in commercial disease management. Direct manipulation of a biocontrol agent resulting in enhancement of diseases control could be achieved by using recent advances in molecular biology techniques. The objectives of this project were to isolate genes from yeast species that were used as postharvest biocontrol agents against postharvest diseases and to determine their role in biocontrol efficacy. The emphasis was to be placed on the yeast, Candida oleophila, which was jointly discovered and developed in our laboratories, and commercialized as the product, Aspire. The general plan was to develop a transformation system for C . oleophila and either knockout or overexpress particular genes of interest. Additionally, biochemical characterization of the lytic peptides was conducted in the wild-type and transgenic isolates. In addition to developing a better understanding of the mode of action of the yeast biocontrol agents, it was also our intent to demonstrate the feasibility of enhancing biocontrol activity via genetic enhancement of yeast with genes known to code for proteins with antimicrobial activity. Major achievements are: 1) Characterization of extracellular lytic enzymes produced by the yeast biocontrol agent Candida oleophila; 2) Development of a transformation system for Candida oleophila; 3) Cloning and analysis of C.oleophila glucanase gene; 4) Overexpression of and knockout of C. oleophila glucanase gene and evaluating its role in the biocontrol activity of C. oleophila; 5) Characterization of defensin gene and its expression in the yeast Pichiapastoris; 6) Cloning and Analysis of Chitinase and Adhesin Genes; 7) Characterization of the rnase secreted by C . oleophila and its inhibitory activity against P. digitatum. This project has resulted in information that enhanced our understanding of the mode of action of the yeast C . oleophila. This was important step towards enhancing the biocontrol activity of the yeast. Fungal cell wall enzymes produced by the yeast antagonist were characterized. Different substrates were identified to enhance there production in vitro. Exo-b-1, 3 glucanase, chitinase and protease production was stimulated by the presence of cell-wall fragments of Penicillium digitatum in the growing medium, in addition to glucose. A transformation system developed was used to study the role of lytic enzymes in the biocontrol activity of the yeast antagonist and was essential for genetic manipulation of C . oleqphila. After cloning and characterization of the exo-glucanase gene from the yeast, the transformation system was efficiently used to study the role of the enzyme in the biocontrol activity by over-expressing or knocking out the activity of the enzyme. At the last phase of the research (still ongoing) the transformation system is being used to study the role of chitinase gene in the mode of action. Knockout and over expression experiments are underway.
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8

Altstein, Miriam, and Ronald J. Nachman. Rational Design of Insect Control Agent Prototypes Based on Pyrokinin/PBAN Neuropeptide Antagonists. United States Department of Agriculture, August 2013. http://dx.doi.org/10.32747/2013.7593398.bard.

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The general objective of this study was to develop rationally designed mimetic antagonists (and agonists) of the PK/PBAN Np class with enhanced bio-stability and bioavailability as prototypes for effective and environmentally friendly pest insect management agents. The PK/PBAN family is a multifunctional group of Nps that mediates key functions in insects (sex pheromone biosynthesis, cuticular melanization, myotropic activity, diapause and pupal development) and is, therefore, of high scientific and applied interest. The objectives of the current study were: (i) to identify an antagonist biophores (ii) to develop an arsenal of amphiphilic topically active PK/PBAN antagonists with an array of different time-release profiles based on the previously developed prototype analog; (iii) to develop rationally designed non-peptide SMLs based on the antagonist biophore determined in (i) and evaluate them in cloned receptor microplate binding assays and by pheromonotropic, melanotropic and pupariation in vivo assays. (iv) to clone PK/PBAN receptors (PK/PBAN-Rs) for further understanding of receptor-ligand interactions; (v) to develop microplate binding assays for screening the above SMLs. In the course of the granting period A series of amphiphilic PK/PBAN analogs based on a linear lead antagonist from the previous BARD grant was synthesized that incorporated a diverse array of hydrophobic groups (HR-Suc-A[dF]PRLa). Others were synthesized via the attachment of polyethylene glycol (PEG) polymers. A hydrophobic, biostablePK/PBAN/DH analog DH-2Abf-K prevented the onset of the protective state of diapause in H. zea pupae [EC50=7 pmol/larva] following injection into the preceding larval stage. It effectively induces the crop pest to commit a form of ‘ecological suicide’. Evaluation of a set of amphiphilic PK analogs with a diverse array of hydrophobic groups of the formula HR-Suc-FTPRLa led to the identification of analog T-63 (HR=Decyl) that increased the extent of diapause termination by a factor of 70% when applied topically to newly emerged pupae. Another biostablePK analog PK-Oic-1 featured anti-feedant and aphicidal properties that matched the potency of some commercial aphicides. Native PK showed no significant activity. The aphicidal effects were blocked by a new PEGylated PK antagonist analog PK-dF-PEG4, suggesting that the activity is mediated by a PK/PBAN receptor and therefore indicative of a novel and selective mode-of-action. Using a novel transPro mimetic motif (dihydroimidazole; ‘Jones’) developed in previous BARD-sponsored work, the first antagonist for the diapause hormone (DH), DH-Jo, was developed and shown to block over 50% of H. zea pupal diapause termination activity of native DH. This novel antagonist development strategy may be applicable to other invertebrate and vertebrate hormones that feature a transPro in the active core. The research identifies a critical component of the antagonist biophore for this PK/PBAN receptor subtype, i.e. a trans-oriented Pro. Additional work led to the molecular cloning and functional characterization of the DH receptor from H. zea, allowing for the discovery of three other DH antagonist analogs: Drosophila ETH, a β-AA analog, and a dF analog. The receptor experiments identified an agonist (DH-2Abf-dA) with a maximal response greater than native DH. ‘Deconvolution’ of a rationally-designed nonpeptide heterocyclic combinatorial library with a cyclic bis-guanidino (BG) scaffold led to discovery of several members that elicited activity in a pupariation acceleration assay, and one that also showed activity in an H. zea diapause termination assay, eliciting a maximal response of 90%. Molecular cloning and functional characterization of a CAP2b antidiuretic receptor from the kissing bug (R. prolixus) as well as the first CAP2b and PK receptors from a tick was also achieved. Notably, the PK/PBAN-like receptor from the cattle fever tick is unique among known PK/PBAN and CAP2b receptors in that it can interact with both ligand types, providing further evidence for an evolutionary relationship between these two NP families. In the course of the granting period we also managed to clone the PK/PBAN-R of H. peltigera, to express it and the S. littoralis-R Sf-9 cells and to evaluate their interaction with a variety of PK/PBAN ligands. In addition, three functional microplate assays in a HTS format have been developed: a cell-membrane competitive ligand binding assay; a Ca flux assay and a whole cell cAMP ELISA. The Ca flux assay has been used for receptor characterization due to its extremely high sensitivity. Computer homology studies were carried out to predict both receptor’s SAR and based on this analysis 8 mutants have been generated. The bioavailability of small linear antagonistic peptides has been evaluated and was found to be highly effective as sex pheromone biosynthesis inhibitors. The activity of 11 new amphiphilic analogs has also been evaluated. Unfortunately, due to a problem with the Heliothis moth colony we were unable to select those with pheromonotropic antagonistic activity and further check their bioavailability. Six peptides exhibited some melanotropic antagonistic activity but due to the low inhibitory effect the peptides were not further tested for bioavailability in S. littoralis larvae. Despite the fact that no new antagonistic peptides were discovered in the course of this granting period the results contribute to a better understanding of the interaction of the PK/PBAN family of Nps with their receptors, provided several HT assays for screening of libraries of various origin for presence of PK/PBAN-Ragonists and antagonists and provided important practical information for the further design of new, peptide-based insecticide prototypes aimed at the disruption of key neuroendocrine physiological functions in pest insects.
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