Potent and Broad-Spectrum Antimicrobial Activity of Analogs from the Scorpion Peptide Stigmurin.

Scorpion venom constitutes a rich source of biologically active compounds with high potential for therapeutic and biotechnological applications that can be used as prototypes for the design of new drugs. The aim of this study was to characterize the structural conformation, evaluate the antimicrobial activity, and gain insight into the possible action mechanism underlying it, for two new analog peptides of the scorpion peptide Stigmurin, named StigA25 and StigA31. The amino acid substitutions in the native sequence for lysine residues resulted in peptides with higher positive net charge and hydrophobicity, with an increase in the theoretical helical content. StigA25 and StigA31 showed the capacity to modify their structural conformation according to the environment, and were stable to pH and temperature variation-results similar to the native peptide. Both analog peptides demonstrated broad-spectrum antimicrobial activity in vitro, showing an effect superior to that of the native peptide, being non-hemolytic at the biologically active concentrations. Therefore, this study demonstrates the therapeutic potential of the analog peptides from Stigmurin and the promising approach of rational drug design based on scorpion venom peptide to obtain new anti-infective agents.

Computational and experimental assessment of efficient dye adsorption method from aqueous effluents by halloysite and palygorskite clay minerals.

The removal of dyes from effluents of textile industries represents a technological challenge, due to their significant environmental impact. The application of halloysite (Hal) and palygorskite (Pal) clay minerals as adsorbents for the removal of Congo red (CR) and methylene blue (MB) was evaluated in this work. The materials were applied both in natural and acid-treated forms, and characterized by XRD, XPS, SEM-EDS, FTIR, and N2 adsorption-desorption isotherm techniques to identify their properties and main active sites. The adsorbents showed potential to remove CR (> 98%) and MB (> 85%) within 180 min, using 0.3 g adsorbent and initial dye concentration of 250 mg L-1. Semi-empirical quantum mechanical calculations (SQM) confirmed the interaction mechanism between dyes and the adsorbents via chemisorption (- 69.0 kcal mol-1 < Eads < - 28.8 kcal mol-1), which was further observed experimentally due to the high fit of adsorption data to pseudo-second order kinetic model (R2 > 0.99) and Langmuir isotherm (R2 > 0.98). The use of Pal and Hal to remove dyes was proven to be economically and environmentally viable for industrial application.

Nootropic effects of LSD: Behavioral, molecular and computational evidence.

The therapeutic use of classical psychedelic substances such as d-lysergic acid diethylamide (LSD) surged in recent years. Studies in rodents suggest that these effects are produced by increased neural plasticity, including stimulation of the mTOR pathway, a key regulator of metabolism, plasticity, and aging. Could psychedelic-induced neural plasticity be harnessed to enhance cognition? Here we show that LSD treatment enhanced performance in a novel object recognition task in rats, and in a visuo-spatial memory task in humans. A proteomic analysis of human brain organoids showed that LSD affected metabolic pathways associated with neural plasticity, including mTOR. To gain insight into the relation of neural plasticity, aging and LSD-induced cognitive gains, we emulated the experiments in rats and humans with a neural network model of a cortico-hippocampal circuit. Using the baseline strength of plasticity as a proxy for age and assuming an increase in plasticity strength related to LSD dose, the simulations provided a good fit for the experimental data. Altogether, the results suggest that LSD has nootropic effects.

Potent and broad-spectrum antimicrobial activity of analogs from the scorpion peptide Stigmurin

Scorpion venom constitutes a rich source of biologically active compounds with high potential for therapeutic and biotechnological applications that can be used as prototypes for the design of new drugs. The aim of this study was to characterize the structural conformation, evaluate the antimicrobial activity, and gain insight into the possible action mechanism underlying it, for two new analog peptides of the scorpion peptide Stigmurin, named StigA25 and StigA31. The amino acid substitutions in the native sequence for lysine residues resulted in peptides with higher positive net charge and hydrophobicity, with an increase in the theoretical helical content. StigA25 and StigA31 showed the capacity to modify their structural conformation according to the environment, and were stable to pH and temperature variationresults similar to the native peptide. Both analog peptides demonstrated broad-spectrum antimicrobial activity in vitro, showing an effect superior to that of the native peptide, being non-hemolytic at the biologically active concentrations. Therefore, this study demonstrates the therapeutic potential of the analog peptides from Stigmurin and the promising approach of rational drug design based on scorpion venom peptide to obtain new anti-infective agents.

Potent and broad-spectrum antimicrobial activity of analogs from the scorpion peptide Stigmurin

Scorpion venom constitutes a rich source of biologically active compounds with high potential for therapeutic and biotechnological applications that can be used as prototypes for the design of new drugs. The aim of this study was to characterize the structural conformation, evaluate the antimicrobial activity, and gain insight into the possible action mechanism underlying it, for two new analog peptides of the scorpion peptide Stigmurin, named StigA25 and StigA31. The amino acid substitutions in the native sequence for lysine residues resulted in peptides with higher positive net charge and hydrophobicity, with an increase in the theoretical helical content. StigA25 and StigA31 showed the capacity to modify their structural conformation according to the environment, and were stable to pH and temperature variationresults similar to the native peptide. Both analog peptides demonstrated broad-spectrum antimicrobial activity in vitro, showing an effect superior to that of the native peptide, being non-hemolytic at the biologically active concentrations. Therefore, this study demonstrates the therapeutic potential of the analog peptides from Stigmurin and the promising approach of rational drug design based on scorpion venom peptide to obtain new anti-infective agents.

Reconstruçäo da aorta com conduto de pericárdio bovino corrugado / Aortic reconstruction with crimped bovine pericardial conduit

No período de outubro de 1989 a maio de 1997, 40 pacientes portadores de dissecçao aórtica, aneurisma da aorta, coarctaçao da aorta ou doença oclusiva aorto-ilíaca foram submetidos a reconstruçao da aorta utilizando-se conduto de pericárdio bovino corrugado processado em glutaraldeído. A reconstruçao total da aorta ascendente com substituiçao da valva aórtica e reimplante das artérias coronárias foi realizada em 9 pacientes, a simples substituiçao da aorta ascendente em 6, aorta torácica descendente em 2, arco aórtico em 1, aorta toracoabdominal em 1 e a aorta abdominal foi reconstruída em 21, incluindo pacientes submetidos a reconstruçao aorto-ilíaca ou aorto-femoral. A mortalidade hospitalar foi de 8 (20 por cento) pacientes e as causas de óbito foram baixo débito cardíaco, recidiva da dissecçao aórtica, falência de múltiplos órgaos e sangramento. O seguimento total foi de 128,4 pacientes-anos, com um seguimento médio de 4 anos por paciente. Complicaçoes tardias relacionadas ao conduto vascular foram observadas em 4 pacientes, incluindo obstruçao de um dos ramos do tubo bifurcado utilizado para reconstruçao aorto-femoral e infecçao em 3, resultando em degeneraçao secundária do conduto e formaçao de pseudo-aneurisma. Os 4 pacientes foram submetidos a reoperaçoes, correspondendo a uma incidência de 3,1 por cento + 1,6 por cento por paciente/ano. Ocorreram 5 óbitos tardios e as causas foram morte súbita, doença coronariana, pneumonia, septicemia e complicaçoes metabólicas resultantes de diabetes e insuficiência renal crônica, correspondendo a uma incidência de 3,9 por cento + 1,7 por cento por paciente/ano. A sobrevida atuarial em 9 anos foi 61,5 por cento + 9,2 por cento, incluindo a mortalidade cirúrgica e a sobrevida atuarial livre de degeneraçao tissular estrutural primária do conduto biológico foi de 100 por cento. O corrugamento do pericárdio, resultante da incorporaçao do princípio crimping utilizado nas próteses vasculares sintéticas, proporciona um conduto circular, que facilita a realizaçao da anstomose, mantém a forma tubular mesmo quando fletido e evita o acotovelamento. O pericárdio é muito macio, fácil de ser manipulado, suturado e coapta muito bem nas linhas de sutura, resultando uma anastomose hemostática. O seguimento de 9 anos demonstrou um desempenho satisfatório deste substituto vascular biológico, nao ocorrendo casos de fibrose, calcificaçao ou dilataçao aneurismática.