Plasmodium vivax metacaspase 1 (PvMCA1) catalytic domain is conserved in field isolates from Brazilian Amazon

In the present study, we investigated the genetic diversity of Plasmodium vivax metacaspase 1 (PvMCA1) catalytic domain in two municipalities of the main malaria hotspot in Brazil, i.e., the Juruá Valley, and observed complete sequence identity among all P. vivax field isolates and the Sal-1 reference strain. Analysis of PvMCA1 catalytic domain in different P. vivax genomic sequences publicly available also revealed a high degree of conservation worldwide, with very few amino acid substitutions that were not related to putative histidine and cysteine catalytic residues, whose involvement with the active site of protease was herein predicted by molecular modeling. The genetic conservation presented by PvMCA1 may contribute to its eligibility as a druggable target candidate in vivax malaria.

Photocatalytic Degradation of Textile dye Orange-122 Via Electrospray Mass Spectrometry

Abstract This work reports the study of the potential application of Zn/TiO2 catalysts, obtained by the sol-gel method, in processes of environmental decontamination through the reactions of photodegradation of textile dye, followed by electrospray mass spectrometry. The catalysts synthesis was performed according to a 2² factorial design with repetition at the central point. The characterization techniques used were: N2 adsorption measurements (BET method), scanning electron microscopy with energy dispersive X-ray (MEV/EDS), X-ray diffraction and point of zero charge (PZC). The photocatalytic tests were performed in batch in the presence of sunlight, and to evaluate the degradation kinetics study, a rapid direct injection electrospray mass spectrometry (DI-ESI-MS) method has been developed. By the photocatalytic tests, the calcination temperature of 400 °C has shown the best results of discoloration for the reactive Orange-122 dye (99.76%) in a reaction time of 2h. The discoloration kinetics were a pseudo-first order, and a statistical analysis was performed to investigate the effects of the variables and to optimize the conditions of discoloration to the dye. After the reactional time of 2 h, an ion of m/z 441.5 was detected by ESI-MS, indicating that the photocatalytic process was effective for the degradation of the dye to secondary compounds.

Genomic analysis of bifunctional Class C-Class D ß-lactamases in environmental bacteria

β-lactamases, which are found in several bacterial species and environments, are the main cause of resistance to β-lactams in Gram-negative bacteria. In 2009, a protein (LRA-13) with two β-lactamase domains (one class C domain and one class D domain) was experimentally characterised, and an extended action spectrum against β-lactams consistent with two functional domains was found. Here, we present the results of searches in the non-redundant NCBI protein database that revealed the existence of a group of homologous bifunctional β-lactamases in the genomes of environmental bacteria. These findings suggest that bifunctional β-lactamases are widespread in nature; these findings also raise concern that bifunctional β-lactamases may be transferred to bacteria of clinical importance through lateral gene transfer mechanisms.

Evaluation of protein undernourishment on the condylar process of the Wistar rat mandible correlation with insulin receptor expression

The mandible condylar process cartilage (CP) of Wistar rats is a secondary cartilage and acts as a mandibular growth site. This phenomenon depends on adequate proteins intake and hormone actions, including insulin. Objectives The present study evaluated the morphological aspects and the expression of the insulin receptor (IR) in the cartilage of the condylar process (CP) of rats subjected to protein undernourishment. Material and Methods The nourished group received a 20% casein diet, while the undernourished group (U) received a 5% casein diet. The re-nourished groups, R and RR, were used to assess the effects of re-nutrition during puberty and adulthood, respectively. CPs were processed and stained with picro-sirius red, safranin-O and azocarmine. Scanning electron microscopy and immunohistochemistry were also performed. Results The area of the CP cartilage and the number of cells in the chondroblastic layer decreased in the U group, as did the thickness of the CP layer in the joint and hypertrophic layer. Renourishment during the pubertal stage, but not during the adult phase, restored these parameters. The cell number was restored when re-nutrition occurred in the pubertal stage, but not in the adult phase. The extracellular matrix also decreased in the U group, but was restored by re-nutrition during the pubertal stage and further increased in the adult phase. IR expression was observed in all CPs, being higher in the chondroblastic and hypertrophic cartilage layers. The lowest expression was found in the U and RR groups. Conclusions Protein malnutrition altered the cellularity, the area, and the fibrous cartilage complex, as well as the expression of the IRs. .

Predictive criteria of insignificant prostate cancer: what is the correspondence of linear extent to percentage of cancer in a single core?

Objective The aim of active surveillance of early prostate cancer is to individualize therapy by selecting for curative treatment only patients with significant cancer. Epstein’s criteria for prediction of clinically insignificant cancer in surgical specimens are widely used. Epstein’s criterion “no single core with >50% cancer” has no correspondence in linear extent. The aim of this study is to find a possible correspondence. Materials and Methods From a total of 401 consecutive patients submitted to radical prostatectomy, 17 (4.2%) met criteria for insignificant cancer in the surgical specimen. The clinicopathologic findings in the correspondent biopsies were compared with Epstein’s criteria for insignificant cancer. Cancer in a single core was evaluated in percentage as well as linear extent in mm. Results Comparing the clinicopathologic findings with Epstein’s criteria predictive of insignificant cancer, there was 100% concordance for clinical stage T1c, no Gleason pattern 4 or 5, ≤2 cores with cancer, and no single core with >50% cancer. However, only 25% had density ≤0.15. The mean, median and range of the maximum length of cancer in a single core in mm were 1.19, 1, and 0.5-2.5, respectively. Additionally, the mean, median, and range of length of cancer in all cores in mm were 1.47, 1.5, and 0.5-3, respectively. Conclusion To pathologists that use Epstein’s criteria predictive of insignificant cancer and measure linear extent in mm, our study favors that “no single core with >50% cancer” may correspond to >2.5 mm in linear extent. .

Precios de los medicamentos: cómo se establecen y cuáles son sus sistemas de control / Drug prices: how they are established and existing price control systems

El precio es una de las principales barreras de acceso a los medicamentos. Por ello es importante conocer cómo se forman los precios y qué factores determinan su cuantía y también qué formas de intervención y regulación son las más adecuadas teniendo en cuenta sus efectos, tanto sobre el acceso, como sobre la innovación, la producción local y otros posibles objetivos de la política de medicamentos. El análisis económico ha desarrollado un conjunto de modelos de mercado que permiten explicar el comportamiento de los precios, aunque los mercados reales divergen sustancialmente de los modelos teóricos. La regulación de precios está justificada por los llamados "fallos de mercado"; la regulación de precios basada en el costo de producción, la modalidad de control de precios más tradicional, ha caído en desuso a favor de los sistemas de precios de referencia internacionales y por la fijación del precio basada en el valor.

Price is one of the main barriers of access to medicines. It is therefore important to understand how prices are formed and what factors determine the amount, as well as what interventions and regulations are the most appropriate considering their effects on access, innovation, local production and other potential objectives of drug policy. Economic analysis has developed a set of market models that can explain the behavior of prices, although actual markets diverge substantially from the theoretical models. Price regulation is justified by the so-called "market failures." Price regulation based on the cost of production, the most traditional form of price control, has fallen into disuse in favor of systems of international reference pricing and value-based pricing.

Complementary data on four methods for sampling free-living ticks in the Brazilian Pantanal / Dados complementares de quatro métodos para amostragem de carrapatos em vida livre no Pantanal brasileiro

In this study, four methods for sampling free-living ticks that are used in ecological and human tick-bite risk studies were evaluated. Cloth dragging, carbon dioxide traps and visual searches and inspection of plant litter on the ground were used in field and forest areas within the Brazilian Pantanal. Among the three tick species collected, Amblyomma sculptum predominated, followed by Amblyomma parvum and Amblyomma ovale. Dragging, a cheap and simple technique, yielded the highest numbers of ticks, particularly nymphs. The visual search detected a high number of adult ticks and provided information on tick questing height. Even though laborious, plant litter examination showed that large numbers of ticks may use this stratum. Carbon dioxide (CO2) traps are expensive and difficult to handle, but they are highly efficient for adult ticks, especially A. parvum. These data indicate that one method alone is incapable of providing a representative sample of the tick fauna in a particular area and that multiple techniques should be used for tick population studies.

Neste estudo, foram avaliados quatro métodos de amostragem de carrapatos em vida livre, usados em estudos ecológicos e avaliação do risco de picadas em humanos. Arraste de flanela, armadilhas de gás carbônico (CO2), busca visual e inspeção de serrapilheira foram aplicados em áreas campestres e florestais no Pantanal brasileiro. Dentre três espécies coletadas, a predominância foi de Amblyomma sculptum, seguida por Amblyomma parvum e Amblyomma ovale. O arraste, técnica simples e de baixo custo, resultou em maior número de carrapatos, particularmente de ninfas. A busca visual detectou alto número de carrapatos adultos e forneceu informações sobre altura de espera por hospedeiros. Apesar de trabalhoso, o exame da serrapilheira demonstrou que grande número de carrapatos pode utilizar esse estrato. Armadilhas de CO2 têm custo elevado e são difíceis de manusear, entretanto, são altamente eficientes para carrapatos adultos, em especial para A. parvum. Esses dados indicam que somente um método é incapaz de fornecer amostra representativa da ixodofauna em uma área particular e que, para estudos populacionais, técnicas múltiplas devem ser usadas.

Impairing methylations at ribosome RNA, a point mutation-dependent strategy for aminoglycoside resistance: The rsmG case / Mutaciones en genes modificadores de ARN ribosómico y la resistencia a aminoglucósidos: el caso del gen rsmG

Introduction: Aminoglycosides like streptomycin are well-known for binding at specific regions of ribosome RNA and then acting as translation inhibitors. Nowadays, several pathogens have been detected to acquire an undefined strategy involving mutation at non structural ribosome genes like those acting as RNA methylases. rsmG is one of those genes which encodes an AdoMet-dependent methyltransferase responsible for the synthesis of m 7 G527 in the 530 loop of bacterial 16S rRNA. This loop is universally conserved, plays a key role in ribosomal accuracy, and is a target for streptomycin binding. Loss of the m 7 G527 modification confers low-level streptomycin resistance and may affect ribosomal functioning. Objectives: After taking into account genetic information indicating that some clinical isolates of human pathogens show streptomycin resistance associated with mutations at rsmG , we decided to explore new hot spots for mutation capable of impairing the RsmG in vivo function and of promoting low-level streptomycin resistance. Materials and methods: To gain insights into the molecular and genetic mechanism of acquiring this aminoglycoside resistance phenotype and the emergence of high-level streptomycin resistance in rsmG mutants, we mutated Escherichia coli rsmG and also performed a genotyping study on rpsL from several isolates showing the ability to grow at higher streptomycin concentrations than parental strains. Results: We found that the mutations at rpsL were preferentially present in these mutants, and we observed a clear synergy between rsmG and rpsL genes to induce streptomycin resistance. Conclusion: We contribute to understand a common mechanism that is probably transferable to other ribosome RNA methylase genes responsible for modifications at central sites for ribosome function.

Introducción. Los aminoglucósidos son moléculas antibióticas capaces de inhibir la síntesis de proteínas bacterianas tras su unión al ribosoma procariota. La resistencia a aminoglucósidos está clásicamente asociada a mutaciones en genes estructurales del ribosoma bacteriano; sin embargo, varios estudios recientes han demostrado, de forma recurrente, la presencia de un nuevo mecanismo dependiente de mutación que no involucra genes estructurales. El gen rsmG es uno de ellos y se caracteriza por codificar una metiltransferasa que sintetiza el nucleósido m 7 G527 localizado en el loop 530 del ribosoma bacteriano, este último caracterizado como sitio preferencial al cual se une la estreptomicina. Objetivo. Partiendo de las recientes asociaciones clínicas entre las mutaciones en el gen rsmG y la resistencia a estreptomicina, este estudio se propuso la caracterización de nuevos puntos calientes de mutación en este gen que puedan causar resistencia a estreptomicina usando Escherichia coli como modelo de estudio. Materiales y métodos. Se indagó sobre el mecanismo genético y molecular por el cual se adquiere la resistencia a estreptomicina y su transición a la resistencia a altas dosis mediante mutagénesis dirigida del gen rsmG y genotipificación del gen rpsL . Resultados. Se encontró que la mutación N39A en rsmG inactiva la proteína y se reportó un nuevo conjunto de mutaciones en rpsL que confieren resistencia a altas dosis de estreptomicina. Conclusiones. Aunque los mecanismos genéticos subyacentes permanecen sin esclarecer, se concluyó que dichos patrones secuenciales de mutación podrían tener lugar en otros genes modificadores del ARN bacteriano debido a la conservación evolutiva y al papel crítico que juegan tales modificaciones en la síntesis de proteínas.

A DNA enzyme targeting Egr-1 inhibits rat vascular smooth muscle cell proliferation by down-regulation of cyclin D1 and TGF-â1

We have demonstrated that a synthetic DNA enzyme targeting early growth response factor-1 (Egr-1) can inhibit neointimal hyperplasia following vascular injury. However, the detailed mechanism of this inhibition is not known. Thus, the objective of the present study was to further investigate potential inhibitory mechanisms. Catalytic DNA (ED5) and scrambled control DNA enzyme (ED5SCR) were synthesized and transfected into primary cultures of rat vascular smooth muscle cells (VSMCs). VSMC proliferation and DNA synthesis were analyzed by the MTT method and BrdU staining, respectively. Egr-1, TGF-â1, p53, p21, Bax, and cyclin D1 expression was detected by RT-PCR and Western blot. Apoptosis and cell cycle assays were performed by FACS. Green fluorescence could be seen localized in the cytoplasm of 70.6 ± 1.52 and 72 ± 2.73 percent VSMCs 24 h after transfection of FITC-labeled ED5 and ED5SCR, respectively. We found that transfection with ED5 significantly inhibited cultured VSMC proliferation in vitro after 24, 48, and 72 h of serum stimulation, and also effectively decreased the uptake of BrdU by VSMC. ED5 specifically reduced serum-induced Egr-1 expression in VSMCs, further down-regulated the expression of cyclin D1 and TGF-â1, and arrested the cells at G0/G1, inhibiting entry into the S phase. FACS analysis indicated that there was no significant difference in the rate of apoptosis between ED5- and ED5SCR-transfected cells. Thus, ED5 can specifically inhibit Egr-1 expression, and probably inhibits VSMC proliferation by down-regulating the expressions of cyclin D1 and TGF-â1. However, ED5 has no effect on VSMC apoptosis.

Identificación de la secuencia del gen de la subunidad catalítica de la telomerasa en Plasmodium falciparum / Identification of the gene sequence of telomerase catalytic subunit in Plasmodium falciparum

Introducción. La enzima telomerasa participa en la regulación de la longitud de los telómeros al sintetizar nuevas repeticiones teloméricas que compensan las pérdidas en cada ronda de replicación del ADN. Por esta razón, el bloqueo de su actividad se plantea como un posible blanco de acción para detener el crecimiento de células con altas tasas de crecimiento. Tal es el caso de Plasmodium falciparum, parásito causante de la forma más grave de paludismo humano, en el cual se sabe que hay actividad de telomerasa pero no se tiene información sobre la enzima misma. Metodología. Para hacer un acercamiento al estudio de la telomerasa en P. falciparum, se realizó un alineamiento múltiple de las secuencias de la subunidad catalítica de la telomerasa disponibles en bases de datos y se obtuvo una secuencia consenso, la cual se comparó con las secuencias generadas en el proyecto de genoma de P. falciparum. Se encontró una secuencia que podría corresponder a parte del gen de la telomerasa de P. falciparum. Para comprobarlo, se diseñaron iniciadores que se utilizaron en ensayos de amplificación sobre el ADN y el ARN del parásito.Resultados. Se amplificaron fragmentos de ADN correspondientes a motivos conservados en las telomerasas y se detectó la presencia del ARNm mediante trascripción reversa y PCR sobre el ADNc generado. De esta manera, al combinar la utilización de herramientas de bioinformática y su posterior comprobación mediante técnicas de biología molecular

Using bradykinin-potentiating peptide structures to develop new antihypertensive drugs

Angiotensin I-converting enzyme (ACE) is a dipeptidyl-carboxypeptidase expressed in endothelial, epithelial and neuroepithelial cells. It is composed of two domains, known as N- and C-domains, and it is primarily involved in blood pressure regulation. Although the physiological functions of ACE are not limited to its cardiovascular role, it has been an attractive target for drug design due to its critical role in cardiovascular and renal disease. We examined natural structures based on bradykinin-potentiating peptides (BPPs) extracted from Bothrops jararaca venom for ACE inhibition. Modeling, docking and molecular dynamics were used to study the conserved residues in the S2’, S1’ and S1 positions that allow enzyme-substrate/inhibitor contacts. These positions are conserved in other oligopeptidases, and they form tight and non-specific contacts with lisinopril, enalapril and BPP9a inhibitors. The only specific inhibitor for human somatic ACE (sACE) was BPP9a, which is instable in the N-sACE-BPP9a complex due to repulsive electrostatic interactions between Arg P4-Arg 412 residues. Specificity for the C-terminal domain in human sACE inhibition was confirmed by electrostatic interaction with the Asp 1008 residue. Peptide-like BPP structures, naturally developed by snakes across millions of years of evolution, appear to be good candidates for the development of domain-selec tive ACE inhibitors with high stability and improved pharmacological profiles.