In vivo antimicrobial evaluation of an alanine-rich peptide derived from Pleuronectes americanus

AbstractIn several organisms, the first barrier against microbial infections consists of antimicrobial peptides (AMPs) which are molecules that act as components of the innate immune system. Recent studies have demonstrated that AMPs can perform various functions in different tissues or physiological conditions. In this view, this study was carried out in order to evaluate the multifunctional activity in vivo of an alanine-rich peptide, known as Pa-MAP, derived from the polar fish Pleuronectes americanus. Pa-MAP was evaluated in intraperitoneally infected mice with a sub-lethal concentration of Escherichia coli at standard concentrations of 1 and 5mgkg−1. At both concentrations, Pa-MAPs exhibited an ability to prevent E. coli infection and increase mice survival, similar to the result observed in mice treated with ampicillin at 2mgkg−1. In addition, mice were monitored for weight loss. The results showed that mice treated with Pa-MAPs at 1mgkg−1 gained 0.8% of body weight during the 72h of experiment. The same was observed with Pa-MAP at 5mgkg−1, which had a gain of 0.5% in body weight during the treatment. Mice treated with ampicillin at 2mgkg−1 show a significant weight loss of 5.6% of body weight. The untreated group exhibited a 5.5% loss of body weight. The immunomodulatory effects were also evaluated by the quantification of IL-10, IL-12, TNF-α, IFN-γ and nitric oxide cytokines in serum, but no immunomodulatory activity was observed. Data presented here suggest that Pa-MAP should be used as a novel antibiotic against infection control

Identification and characterization of a bactericidal and proapoptotic peptide from cycas revoluta seeds with DNA binding properties

Nowadays, novel pharmacies have been screened from plants. Among them are the peptides, which show multiple biotechnological activities. In this report, a small peptide (Ala–Trp–Lys–Leu–Phe–Asp–Asp–Gly–Val) with a molecular mass of 1,050 Da was purified from Cycas revoluta seeds by using reversed-phase liquid chromatography. This peptide shows clear deleterious effects against human epidermoid cancer (Hep2) and colon carcinoma cells (HCT15). It caused inhibition of cancer cell proliferation and further disruption of nucleosome structures, inducing apoptosis by direct DNA binding. A remarkable antibacterial activity was also observed in this same peptide. Nevertheless, no significant lysis of normal RBC cells was observed in the presence of peptide. Additionally, an acetylation at the N-termini portion is able to reduce both activities. Bioinformatics tools were also utilized for construction of a three-dimensional model showing a single amphipathic helix. Since in vitro binding studies show that the target of this peptide seems to be DNA, theoretical docking studies were also performed to better understand the interaction between peptide and nucleic acids and also to shed some light on the acetyl group role. Firstly, binding studies showed that affinity contacts basically occur due to electrostatic attraction. The complex peptide-ssDNA was clearly oriented by residues Ala1, Lys3 and Asp6, which form several hydrogen bonds that are able to stabilize the complex. When acetyl was added, hydrogen bonds are broken, reducing the peptide affinity. In summary, it seems that information here provided could be used to design a novel derivative of this peptide which a clear therapeutic potential

Glucose directly promotes antifungal resistance in the fungal pathogen, Candida spp

Effects of glucose on the susceptibility of antifungal agents are investigated against Candida spp. Increasing the concentration of glucose decreased the activity of antifungal agents, voriconazole was mostly affected drugs followed by amphotericin B. No significant change has been observed for anidulafungin. Biophysical interaction between antifungal agents with glucose molecules were investigated using ITC, FTIR and 1HNMR. Glucose have higher affinity to bind with voriconazole by hydrogen bonding and decrease the susceptibility. In addition to confirm the results observed in vitro, theoretical docking studies demonstrated that voriconazole presented three important hydrogen bonds and amphotericin B presented two hydrogen bonds that stabilized the complex compound-glucose. In vivo results also suggest that the physiologically relevant higher glucose level in blood stream of Diabetes Mellitus (DM) mice might interact with the available selective agents during antifungal therapy, decreased the activity by complex formation. Thus, selection of drugs for DM patient is important to control the infectious diseases

A polyalanine peptide derived from polar fish with anti-infectious activities

Due to the growing concern about antibiotic-resistant microbial infections, increasing support has been given to new drug discovery programs. A promising alternative to counter bacterial infections includes the antimicrobial peptides (AMPs), which have emerged as model molecules for rational design strategies. Here we focused on the study of Pa-MAP 1.9, a rationally designed AMP derived from the polar fish Pleuronectes americanus. Pa-MAP 1.9 was active against Gram-negative planktonic bacteria and biofilms, without being cytotoxic to mammalian cells. By using AFM, leakage assays, CD spectroscopy and in silico tools, we found that Pa-MAP 1.9 may be acting both on intracellular targets and on the bacterial surface, also being more efficient at interacting with anionic LUVs mimicking Gram-negative bacterial surface, where this peptide adopts α-helical conformations, than cholesterol-enriched LUVs mimicking mammalian cells. Thus, as bacteria present varied physiological features that favor antibiotic-resistance, Pa-MAP 1.9 could be a promising candidate in the development of tools against infections caused by pathogenic bacteria.National Institute of Allergy and Infectious Diseases (U.S.) (R21AI098701

Antifungal nanofibers made by controlled release of sea animal derived peptide

© The Royal Society of Chemistry 2015Candida albicans is a common human-pathogenic fungal species with the ability to cause several diseases including surface infections. Despite the clear difficulties of Candida control, antimicrobial peptides (AMPs) have emerged as an alternative strategy for fungal control. In this report, different concentrations of antifungal Cm-p1 (Cencritchis muricatus peptide 1) were electrospun into nanofibers for drug delivery. The nanofibers were characterized by mass spectrometry confirming the presence of the peptide on the scaffold. Atomic force microscopy and scanning electronic microscopy were used to measure the diameters, showing that Cm-p1 affects fiber morphology as well as the diameter and scaffold thickness. The Cm-p1 release behavior from the nanofibers demonstrated peptide release from 30 min to three days, leading to effective yeast control in the first 24 hours. Moreover, the biocompatibility of the fibers were evaluated through a MTS assay as well as ROS production by using a HUVEC model, showing that the fibers do not affect cell viability and only nanofibers containing 10% Cm-p1–PVA improved ROS generation. In addition, the secretion of pro-inflammatory cytokines IL-6 and TNF-α by the HUVECs was also slightly modified by the 10% Cm-p1–PVA nanofibers. In conclusion, the electrospinning technique applied here allowed for the manufacture of biodegradable biomimetic nanofibrous extracellular membranes with the ability to control fungal infectionThis work was supported by CAPES, FUNDECT, CNPq, FAPDF, UCB, Fundação para a Ciência e Tecnologia – Ministério da Educação e Ciência (FCT-MEC, Portugal) and the Calouste Gulbenkian Foundation (Portugal

Evaluation of an Antimicrobial L-Amino Acid Oxidase and Peptide Derivatives from Bothropoides mattogrosensis Pitviper Venom

Healthcare-associated infections (HAIs) are causes of mortality and morbidity worldwide. The prevalence of bacterial resistance to common antibiotics has increased in recent years, highlighting the need to develop novel alternatives for controlling these pathogens. Pitviper venoms are composed of a multifaceted mixture of peptides, proteins and inorganic components. L-amino oxidase (LAO) is a multifunctional enzyme that is able to develop different activities including antibacterial activity. In this study a novel LAO from Bothrops mattogrosensis (BmLAO) was isolated and biochemically characterized. Partial enzyme sequence showed full identity to Bothrops pauloensis LAO. Moreover, LAO here isolated showed remarkable antibacterial activity against Gram-positive and -negative bacteria, clearly suggesting a secondary protective function. Otherwise, no cytotoxic activities against macrophages and erythrocytes were observed. Finally, some LAO fragments (BmLAO-f1, BmLAO-f2 and BmLAO-f3) were synthesized and further evaluated, also showing enhanced antimicrobial activity. Peptide fragments, which are the key residues involved in antimicrobial activity, were also structurally studied by using theoretical models. The fragments reported here may be promising candidates in the rational design of new antibiotics that could be used to control resistant microorganisms

Insights into Animal and Plant Lectins with Antimicrobial Activities

Lectins are multivalent proteins with the ability to recognize and bind diverse carbohydrate structures. The glyco -binding and diverse molecular structures observed in these protein classes make them a large and heterogeneous group with a wide range of biological activities in microorganisms, animals and plants. Lectins from plants and animals are commonly used in direct defense against pathogens and in immune regulation. This review focuses on sources of animal and plant lectins, describing their functional classification and tridimensional structures, relating these properties with biotechnological purposes, including antimicrobial activities. In summary, this work focuses on structural-functional elucidation of diverse lectin groups, shedding some light on host-pathogen interactions; it also examines their emergence as biotechnological tools through gene manipulation and development of new drugs