Synthesis of Peptaibolin, an antimicrobial peptide

To tackle one of the biggest global health problems, the resistance of microorganisms to antibiotics, a collective effort in the search for more effective agents against bacteria was required. Peptides with antimicrobial activity have been raising much attention as a promising alternative for antibiotics. Peptaibols, for instance, are a family of antimicrobial peptides (AMPs) with great biomedical potential, in which the Peptaibolin can be highlighted. This peptide has gained relevance due to its small amino acids content, only four, and its acetyl group and a phenylalaninol residue (Phol) at the N-terminal and C-terminal, respectively. Here, we report the synthesis of Peptaibolin through Solid Phase Peptide Synthesis assisted by Microwave heating (MW-SPPS) in a pre-loaded Phe-Wang resin. Starting from a loading of 0.51 mmol/g, two syntheses were made, using two different combinations of coupling reagents. The best option was DIC/Oxima, achieving a yield of 50.0%. Proton Nuclear Magnetic Resonance (1H-NMR) studies confirmed the peptide structure, while High Performance Liquid Chromatography (HPLC) verified the peptide purity. The peptide solubility was examined against several combinations of solvents. Peptaibolin was not soluble in water, only in organic solvents or in the combination of both. Antimicrobial testing was conducted using Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa. Minimum inhibitory concentration studies demonstrated the resistance of bacteria to the peptide action and the peptide instability in bacterial growth conditionsFundação para a Ciência e Tecnologia-FCT (Portugal) for funding through CQUM (UID/QUI/00686/2020) and project PTDC/QUI-COL/28052/2017. The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT. Authors also acknowledge FCT for funding the project PEPTEX with reference PTDC/CTM-TEX/28074/2017 (POCI-01-0145-FEDER-028074). They acknowledge project UID/CTM/00264/2021 of Centre for Textile Science and Technology (2C2T), funded by national funds through FCT/MCTE

Deri yara kaplamalarindaki uygulamalar için elektrik alan lif çekim ile üretilmiş Tiger 17 peptit yüklü polikaprolakton/selüloz asetat nano lifli matlar

A skin wound if not properly treated can result in a chronic wound susceptible to widespread infections, which can result in the patient's death. Currently, tissue engineering is described as an interdisciplinary field that combines principles of engineering, chemistry and biology to generate solutions that allow to repair, restore and/or improve the functions of injured tissues. In the same sense, the textile area addresses solutions based on polymeric fibers, produced from a wide range of polymers, which allow the generation of structures with a large surface area, porosity and mechanical resistance that can be used as bioactive dressings that promote a healing and efficient antimicrobial activity. This research work focused on the synthesis of Tiger 17, through microwave-assisted solid-phase synthesis methodologies, and Tiger 17 commercially obtained, respective structural characterization and evaluation of the antimicrobial capacity. Simultaneously, nanofibrous polymer matrices were produced using the electrospinning technique with the aim of immobilizing the developed biomolecule and thus creating potential vehicles for a local and sustainable antimicrobial action (controlled release). In order to verify its physical and chemical properties, advanced characterization techniques were used: proton nuclear magnetic resonance, high performance liquid chromatography, optical microscopy, scanning electron microscopy, fourier transform infrared spectroscopy–attenuated total reflectance, thermogravimetry, differential scanning calorimetry, contact angle and surface energy and determination of porosity and hydration.Düzgün tedavi edilmeyen bir cilt yarası, hastanın ölümüyle sonuçlanabilecek yaygın enfeksiyonlara duyarlı kronik bir yaraya neden olabilir. Günümüzde doku mühendisliği, hasarlı dokuların işlevlerini onarmaya, eski haline getirmeye ve/veya iyileştirmeye olanak tanıyan çözümler üretmek için mühendislik, kimya ve biyolojinin ilkelerini birleştiren disiplinler arası bir alan olarak tanımlanmaktadır. Bu kapsamda, tekstil, iyileşmeyi ve etkili antimikrobiyal aktiviteyi teşvik eden biyoaktif pansuman olarak kullanılabilecek, geniş yüzey alanlı, gözenekli ve mekanik dirençli yapıların oluşturulmasına izin veren, geniş bir polimer yelpazesinden üretilen liflere dayalı çözümler sunmaktadır. Bu araştırma çalışması, mikrodalga destekli katı faz sentez metodolojileri aracılığıyla Tiger 17'nin sentezine ve ticari olarak temin edilen Tiger 17 ile birlikte yapısal karakterizasyonunun ve antimikrobiyal kapasitenin değerlendirilmesine odaklanmıştır. Aynı zamanda, geliştirilen biyomolekülü hareketsiz hale getirmek ve böylece lokal ve sürdürülebilir bir antimikrobiyal etki (kontrollü salım) için potansiyel çözümler yaratmak amacıyla elektrik alan lif üretim tekniği kullanılarak nanolifli polimer matrisler üretildi. Yapının fiziksel ve kimyasal özelliklerini doğrulamak için, proton nükleer manyetik rezonans, yüksek performanslı sıvı kromatografisi, optik mikroskopi, taramalı elektron mikroskobu, fourier dönüşümü kızılötesi spektroskopisi-zayıflatılmış toplam yansıma, termogravimetri, diferansiyel taramalı kalorimetri, temas açısı, yüzey enerjisi, gözeneklilik ve su tutma ölçümleri gibi ileri karakterizasyon teknikleri kullanıldı

Development and validation of a simple and rapid capillary zone electrophoresis method for determination of nnrti nevirapine in pharmaceutical formulations

A simple and fast capillary zone electrophoresis (CZE) method has been developed and validated for quantification of a non-nucleoside reverse transcriptase inhibitor (NNRTI) nevirapine, in pharmaceuticals. The analysis was optimized using 10 mmol L-1 sodium phosphate buffer pH 2.5, +25 kV applied voltage, hydrodynamic injection 0.5 psi for 5 s and direct UV detection at 200 µm. Diazepam (50.0 µg mL-1) was used as internal standard. Under these conditions, nevirapine was analyzed in approximately less than 2.5 min. The analytical curve presented a coefficient of correlation of 0.9994. Limits of detection and quantification were 1.4 µg mL-1 and 4.3 µg mL-1, respectively. Intra- and inter-day precision expressed as relative standard deviations were 1.4% and 1.3%, respectively and the mean recovery was 100.81%. The active pharmaceutical ingredient was subjected to hydrolysis (acid, basic and neutral) and oxidative stress conditions. No interference of degradation products and tablet excipients were observed. This method showed to be rapid, simple, precise, accurate and economical for determination of nevirapine in pharmaceuticals and it is suitable for routine quality control analysis since CE offers benefits in terms of quicker method development and significantly reduced operating costs.Um método simples e rápido por eletroforese capilar foi desenvolvido e validado para a quantificação do inibidor não nucleosídeo da transcritase reversa (NNRTI) nevirapina, em medicamentos. A análise foi otimizada utilizando tampão fosfato de sódio 10 mmol L-1, pH 2,5, voltagem aplicada de +25 kV, injeção hidrodinâmica a 0,5 psi por 5 s e detecção UV em 200 µm. Diazepam (50,0 µg mL-1) foi usado como padrão interno. Sob estas condições, nevirapina foi analisada em aproximadamente menos de 2,5 min. A curva analítica apresentou um coeficiente de correlação de 0,9994. Os limites de detecção e quantificação foram 1,4 µg mL-1 e 4,3 µg mL-1, respectivamente. Precisões intra e inter-dia expressas como desvio padrão relativo foram 1,4% e 1,3%, respectivamente e a recuperação média foi de 100,81%. O fármaco foi submetido a testes de hidrólises (ácida, básica e neutra) e a estresse oxidativo. Não foi observada interferência por parte dos produtos de degradação, nem dos excipients na análise da nevirapina. Este método mostrou ser rápido, simples, preciso, exato e econômico para a determinação de nevirapina em produtos farmacêuticos e é apropriado para o controle de qualidade em análise de rotina uma vez que a eletroforese capilar oferece benefícios em termos de desenvolvimento rápido dos métodos e custos muito reduzidos de operação.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Análise da diversidade genética de variedades tradicionais de feijoeiro comum utilizando marcadores microssatélites.

No Brasil, foi estabelecida, a partir da década de 70, uma rede de pesquisa com ênfase na conservação e uso dos recursos genéticos do feijoeiro comum. O banco de germoplasma da Embrapa Arroz e Feijão detém aproximadamente 17.345 acessos, dos quais 4.325 são variedades tradicionais (VTs). Esses acessos representam uma rica fonte de genes que conferem adaptação a diferentes ambientes, resistência a doenças e propriedades agronômicas diferenciadas que podem ser exploradas por meio de técnicas moleculares que fornecem medidas bastante eficientes e diretas da variabilidade genética existente dentro e entre os acessos. Esse estudo teve como objetivo a avaliação da variabilidade genética de VTs de feijoeiro comum utilizando marcadores microssatélites (SSRs).Pôster - graduação

Fibrogenesis in Kidney Transplant: Dysfunction Progress Biomarkers

Fibrogenesis markers, such as alpha-actin (AA), CD163 (macrophages), and E-cadherin, have been studied as chronic kidney allograft injury (CAI) predictors, a major cause of allograft failure. OBJECTIVE: Investigate the value of these markers in predicting CAI and initiation of dialysis. MATERIALS AND METHODS: Retrospective analysis of 26 kidney allograft biopsies (from 22 patients with CAI) during 2 years, evaluating intensity and percentage of marked cells on glomeruli and tubulointerstitial compartment. At the time of the biopsy, patients were 45.5 ± 15.8 years and 4.2 years after transplant, and they had a mean glomerular filtration rate (GFR) of 25.8 ± 9.9 mL/min. From an average of 8.5 glomeruli per biopsy, there was ≤25% sclerosis in 17 cases, 26% to 50% in 5, and >50% in 4. Interstitial fibrosis or tubular atrophy affected ≤25% of cortical area in 14 cases, 26% to 50% in 8, and >50% in 2. Twelve patients started dialysis 5.8 ± 4.7 years after transplant, with an average GFR 20.9 mL/min at the time of the biopsy. RESULTS: There was a higher intensity and percentage of CD163-marked cells in the tubulointerstitial compartment in advanced interstitial fibrosis. We found an association between intensity of AA in the tubulointerstitial compartment and initiation of dialysis (P = .003) and a negative correlation between intensity of E-cadherin loss and GFR (r = -0.56, P = .012). CONCLUSIONS: In our study, intensity of tubulointerstitial AA was shown to be a predictor of initiation of dialysis, and E-cadherin loss intensity was associated to CAI progression. However, prospective and larger studies are needed to evaluate the predictive value of these markers.info:eu-repo/semantics/publishedVersio

Biodegradable wet-spun fibers modified with antimicrobial agents for potential applications in biomedical engineering

Wet-spinning is a non-solvent induced phase inversion technique that allows the production of continuous polymeric microfibers, with a uniform morphology, based on the principle of precipitation. It allows the production of 3D fibrous constructs with an intricated architecture that facilitates cell infiltration, something that is very limited in electrospun nanofibrous mats, thus increasing its interest in biomedicine. Wet-spun scaffolds are also more easily processed and can be loaded with a variety of biomolecules of interest. Antimicrobial agents that display a broad spectrum of activity against bacteria, fungi and viruses have been combined with such constructs demonstrating great potential to fight infections. In the present work, we explore the use of wet-spinning to process both natural and synthetic biodegradable polymers in the form of microfibers, and the necessary processes to modify their surface to increase their antimicrobial profile. The synergistic potential of specialized biomolecules within wet-spun fibrous architectures are also highlighted.Authors acknowledge the Foundation for Science and Technology (FCT) of Portugal for funding the projects PTDC/CTM-TEX/28074/2017 (POCI-01-0145-FEDER-028074) and UID/CTM/00264/2020 from 2C2T

What Can We Do When All Collapses? Fatal Outcome of Collapsing Glomerulopathy and Systemic Lupus Erythematosus With Diffuse Alveolar Hemorrhage: Case Report

NTRODUCTION: Collapsing glomerulopathy (CG) is a rare form of glomerular injury. Although commonly associated with human immunodeficiency virus (HIV) infection, it can occur in association with systemic lupus erythematosus (SLE). CASE REPORT: We present the case of a 50-year-old man, with chronic kidney disease secondary to focal and segmental glomerulosclerosis, who received a cadaveric kidney transplant in 2007. There were no relevant intercurrences until May 2015, when he presented with nephrotic range proteinuria (± 4 g/d). A graft biopsy was performed and it did not show any significant pathological changes. In September, he developed a full nephrotic syndrome (proteinuria 19 g/d) and a graft biopsy was repeated. CG features were evident with a rich immunofluorescence. Antinuclear antibodies (ANA) and anti-double-stranded DNA (anti-dsDNA) antibodies were positive; the remaining immunologic study was normal. Viral markers for HIV, hepatitis C virus (HCV), and hepatitis B virus (HBV) were negative. The patient was treated with corticosteroid pulses and plasmapheresis (seven treatments). A rapid deterioration of kidney function was seen and he became dialysis dependent. He was discharged with a low-dose immunosuppressive treatment. In October, he was hospitalized with diffuse alveolar hemorrhage (DAH). The auto-immune study was repeated, revealing complement consumption and positive titers of ANA and Anti-dsDNA antibodies. Anti-neutrophil cytoplasmic antibodies (ANCAs) and antiglomerular basement membrane antibody (anti-GBM) were negative. Treatment with intravenous corticosteroids, plasmapheresis, and human immunoglobulin was ineffective and the outcome was fatal. CONCLUSION: This case report highlights the possible association of CG and SLE. To our knowledge, it is the first case of SLE presenting with CG and DAH, with the singularity of occurring in a kidney transplant recipient receiving immunosuppression.info:eu-repo/semantics/publishedVersio