scholarly journals Biocompatibilidad y actividad microbiana de sulfuro de plata nanoestructurado para aplicación en biomateriales: revisión sistemática

2021 ◽  
Vol 14 (27) ◽  
pp. 1e-14e
Author(s):  
Aimee Marlene Mendoza Avilés ◽  
Mercedes Guadalupe Mendoza Ornelas ◽  
Lilia Michelle Andrade Martínez ◽  
Héctor Javier Miranda Fernández ◽  
Sayra Susana Mares Muñoz ◽  
...  
Keyword(s):  
Web Of Science ◽  
E Coli ◽  
Palabras Clave ◽  
Revisión Sistemática

Actualmente nos enfrentamos a un panorama díficil por la marcada resistencia antibiotica a los agentes antimicrobianos existentes. Las infecciones microbianas representan una importante amenaza clínica por lo que es necesario buscar alternativas de nuevos agentes, realizando pruebas de sensibilidad microbiana y de biocompatibilidad. El objetivo de esta revisión es realizar una búsqueda sistemática sobre la actividad microbiana y la biocompatibilidad de nanoestructuras de sulfuro de plata, para aplicaciones en los biomateriales. La búsqueda se realizó en las bases de datos ScienceDirect, Web of science y PubMed en octubre de 2020, utilizando las palabras clave: biocompatibilidad, viabilidad celular, actividad antimicrobiana o efecto antifúngico. Se siguieron los lineamientos del PRISMA para las revisiones sistemáticas. Los trece artículos incluidos de estudios in vitro o in vivo mostraron que las nanoestructuras de sulfuro de plata inhiben microrganismos Gram(+) y Gram (-) como S. aureus y E. coli, respectivamente, sin importar el tamaño. Puntos cuánticos menores a 5 nm de sulfuro de plata presentan más del 65% de viabilidad celular con fibroblastos o células humanas. Se concluye que la actividad antimicrobiana y viabilidad celular que presentan las nanoestructuras de sulfuro de plata no mostraron una dependencia con el tamaño y la concentración, pero podrían utilizarse en biomateriales.

scholarly journals Nanocompuestos de quitosano aplicados al campo de la medicina regenerativa. Una revisión sistemática

2020 ◽  
Vol 25 (4) ◽  
pp. 604-615
Author(s):  
Yeidy Viviana Arias-Andrade ◽  
Luz Angela Veloza ◽  
Juan Carlos Sepúlveda-Arias
Keyword(s):  
Web Of Science ◽  
Assessment Tool ◽  
Reliability Assessment ◽  
Data Reliability ◽  
Revisión Sistemática ◽  
Toxicological Data

El quitosano es un biopolímero obtenido de la quitina presente en el exoesqueleto de crustáceos, insectos, arácnidos y en la pared celular de los hongos. Investigaciones recientes han confirmado el uso del quitosano como biomaterial prometedor debido a características como estructura porosa, facilidad de modificación química, alta afinidad hacia macromoléculas in vivo, entre otras. El objetivo de este trabajo fue evaluar las aplicaciones del quitosano como biomaterial en medicina regenerativa. Se realizó una búsqueda de la literatura en el período comprendido entre 2013-2018 en las bases de datos PubMed, Scopus, Web of Science y Embase. En esta revisión, la herramienta “ToxRTool” (Toxicological data Reliability Assessment Tool) se usó para evaluar la calidad y confiabilidad metodológica de los estudios evaluados. Los nanocompuestos de quitosano se están evaluando con metodologías in vitro (92.59%), empleando diversos componentes de acople y en múltiples aplicaciones. Sin embargo, la falta de información metodológica con relación al uso de controles en los estudios dificulta la reproducibilidad de los mismos e introducen limitaciones para el posterior desarrollo de estudios in vivo. La herramienta ToxRTool fue útil para identificar ocho estudios (29.6%) como “Confiable sin restricciones” y 19 estudios (70.4%) como “Confiable con restricciones”, indicando que se requieren estudios más cuidadosos con relación a la toxicidad de los nanocompuestos de quitosano. El quitosano es un biomaterial versátil lo que ha permitido su incorporación en una amplia variedad de componentes mejorando sus propiedades biológicas, mecánicas y físicas, obteniendo así nanocompuestos cada vez más útiles y eficaces para uso nanomedicina.

scholarly journals Efectos biológicos y uso herbolario del género Croton. Revisión sistemática

2020 ◽  
Vol 8 (16) ◽  
pp. 194-200
Author(s):  
Guadalupe C. Romero-Juárez ◽  
Mario I Ortiz ◽  
Raquel Cariño-Cortés
Keyword(s):  
Web Of Science ◽  
Revisión Sistemática

AntecedentesDesde la antigüedad, los seres humanos han tenido la necesidad de buscar alternativas naturales para combatir diversas enfermedades. Los principios activos de géneros de Croton (familia Euphobiaceae) se usan como alternativas terapéuticas naturales en la medicina tradicional en África, sur de Asia y Sudamérica. Específicamente, Croton hypoleucus (Ch) se usa en la medicina tradicional mexicana para el tratamiento del dolor de estómago, gastritis, tos e infecciones locales. Por tanto, el objetivo principal de la presente revisión es mostrar las actividades biológicas y los usos clínicos de Croton. Método Se realizó una búsqueda bibliográfica en PubMed, Scopus, Web of Science. Revisamos los estudios experimentales de modelos in vitro e in vivo de los componentes de las diferentes especies de Croton publicados de 1980 a 2019, donde de cada artículo se sintetizó la información sobre la eficacia y los efectos biológicos de cada compuesto aislado. Resultados Se incluyeron un total de 16 estudios experimentales. No se encontraron estudios clínicos en la literatura. Algunas especies de croton produjeron actividad citotóxica de baja a moderada contra diferentes líneas celulares. Estos efectos se atribuyen principalmente a diterpenoides, crotónidos y principalmente a clerodanos. Un extracto puro de Croton hypoleucus demostró moderada actividad hepatoprotectora y antioxidante. Conclusión La literatura indica el posible mecanismo de acción de algunas actividades biológicas de los compuestos de Croton. Sin embargo, la información disponible es escasa. Por lo tanto, se necesita realizar más estudios en diferentes modelos experimentales para clarificar la seguridad y eficacia de sus componentes activos con el fin de tener alternativas naturales con el mismo efecto o mejor que los medicamentos convencionales.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

scholarly journals Functional identification of ygiP as a positive regulator of the ttdA-ttdB-ygjE operon

Microbiology ◽  
2006 ◽  
Vol 152 (7) ◽  
pp. 2129-2135 ◽  
Author(s):  
Taku Oshima ◽  
Francis Biville
Keyword(s):  
Functional Characterization ◽  
Anaerobic Growth ◽  
Functional Identification ◽  
New Members ◽  
E Coli ◽  
Inner Membrane Protein ◽  
Tartrate Dehydratase

Functional characterization of unknown genes is currently a major task in biology. The search for gene function involves a combination of various in silico, in vitro and in vivo approaches. Available knowledge from the study of more than 21 LysR-type regulators in Escherichia coli has facilitated the classification of new members of the family. From sequence similarities and its location on the E. coli chromosome, it is suggested that ygiP encodes a lysR regulator controlling the expression of a neighbouring operon; this operon encodes the two subunits of tartrate dehydratase (TtdA, TtdB) and YgiE, an integral inner-membrane protein possibly involved in tartrate uptake. Expression of tartrate dehydratase, which converts tartrate to oxaloacetate, is required for anaerobic growth on glycerol as carbon source in the presence of tartrate. Here, it has been demonstrated that disruption of ygiP, ttdA or ygjE abolishes tartrate-dependent anaerobic growth on glycerol. It has also been shown that tartrate-dependent induction of the ttdA-ttdB-ygjE operon requires a functional YgiP.

scholarly journals Arabidopsis Disulfide Reductase, Trx-h2, Functions as an RNA Chaperone under Cold Stress

2021 ◽  
Vol 11 (15) ◽  
pp. 6865
Author(s):  
Eun Seon Lee ◽  
Joung Hun Park ◽  
Seong Dong Wi ◽  
Ho Byoung Chae ◽  
Seol Ki Paeng ◽  
...  
Keyword(s):  
Cold Stress ◽  
Wild Type ◽  
Rna Chaperone ◽  
E Coli ◽  
Cold Sensitive ◽  
Thioredoxin H ◽  
Functional Rnas

The thioredoxin-h (Trx-h) family of Arabidopsis thaliana comprises cytosolic disulfide reductases. However, the physiological function of Trx-h2, which contains an additional 19 amino acids at its N-terminus, remains unclear. In this study, we investigated the molecular function of Trx-h2 both in vitro and in vivo and found that Arabidopsis Trx-h2 overexpression (Trx-h2OE) lines showed significantly longer roots than wild-type plants under cold stress. Therefore, we further investigated the role of Trx-h2 under cold stress. Our results revealed that Trx-h2 functions as an RNA chaperone by melting misfolded and non-functional RNAs, and by facilitating their correct folding into active forms with native conformation. We showed that Trx-h2 binds to and efficiently melts nucleic acids (ssDNA, dsDNA, and RNA), and facilitates the export of mRNAs from the nucleus to the cytoplasm under cold stress. Moreover, overexpression of Trx-h2 increased the survival rate of the cold-sensitive E. coli BX04 cells under low temperature. Thus, our data show that Trx-h2 performs function as an RNA chaperone under cold stress, thus increasing plant cold tolerance.

scholarly journals Effects of Bacterial CLPB Protein Fragments on Food Intake and PYY Secretion

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2223
Author(s):  
Manon Dominique ◽  
Nicolas Lucas ◽  
Romain Legrand ◽  
Illona-Marie Bouleté ◽  
Christine Bôle-Feysot ◽  
...  
Keyword(s):  
Food Intake ◽  
Peptide Yy ◽  
Molecular Mimicry ◽  
Potential Effect ◽  
In Vivo Studies ◽  
Sprague Dawley ◽  
E Coli ◽  
In Vivo Effects

CLPB (Caseinolytic peptidase B) protein is a conformational mimetic of α-MSH, an anorectic hormone. Previous in vivo studies have already shown the potential effect of CLPB protein on food intake and on the production of peptide YY (PYY) by injection of E. coli wild type (WT) or E. coli ΔClpB. However, until now, no study has shown its direct effect on food intake. Furthermore, this protein can fragment naturally. Therefore, the aim of this study was (i) to evaluate the in vitro effects of CLPB fragments on PYY production; and (ii) to test the in vivo effects of a CLPB fragment sharing molecular mimicry with α-MSH (CLPB25) compared to natural fragments of the CLPB protein (CLPB96). To do that, a primary culture of intestinal mucosal cells from male Sprague–Dawley rats was incubated with proteins extracted from E. coli WT and ΔCLPB after fragmentation with trypsin or after a heat treatment of the CLPB protein. PYY secretion was measured by ELISA. CLPB fragments were analyzed by Western Blot using anti-α-MSH antibodies. In vivo effects of the CLPB protein on food intake were evaluated by intraperitoneal injections in male C57Bl/6 and ob/ob mice using the BioDAQ® system. The natural CLPB96 fragmentation increased PYY production in vitro and significantly decreased cumulative food intake from 2 h in C57Bl/6 and ob/ob mice on the contrary to CLPB25. Therefore, the anorexigenic effect of CLPB is likely the consequence of enhanced PYY secretion.

scholarly journals Glycemic Index of Gluten-Free Bread and Their Main Ingredients: A Systematic Review and Meta-Analysis

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 506
Author(s):  
Bernardo Romão ◽  
Ana Luísa Falcomer ◽  
Gabriela Palos ◽  
Sandra Cavalcante ◽  
Raquel Braz Assunção Botelho ◽  
...  
Keyword(s):  
Systematic Review ◽  
Glycemic Index ◽  
Resistant Starch ◽  
Web Of Science ◽  
Meta Analysis ◽  
Gluten Free ◽  
Inclusion Criteria ◽  
Glycemic Profile

This study aimed to perform a systematic review and meta-analysis of the glycemic index (GI) of gluten-free bread (GFB) and its main ingredients. The systematic review followed PRISMA guidelines, using seven electronic databases (PubMed, EMBASE, Scopus, Science Direct, Web of Science, gray literature research with Google Scholar, and patents with Google Patent tool), from inception to November 2020. Eighteen studies met the inclusion criteria evaluating 132 GFB samples. Five articles tested GI in vivo, eleven in vitro; and two studies tested both methods. The analysis showed that 60.7% (95% CI: 40.2–78.1%) of the samples presented high glycemic indexes, evidencing a high glycemic profile for GFB. Only 18.2% (95% CI: 11.7–27.2%) of the bread samples presented in the studies were classified as a low GI. Meta-analysis presented moderate/low heterogenicity between studies (I2 = 61% and <1% for both high and low GIs) and reinforced the proportion of high GIs. Lower GIs were found in formulations based on Colocasia esculenta flour or enriched with fiber, yogurt and curd cheese, sourdough, psyllium, hydrocolloids, enzymes, fructans, and resistant starch, highlighting the efficacy of these ingredients to lower GFBs’ GI. GFB tends to present high GI, impacting the development of chronic diseases when consumed.

scholarly journals Lysyl-tRNA synthetase from Escherichia coli K12. Chromatographic heterogeneity and the lysU-gene product

1987 ◽  
Vol 248 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J Charlier ◽  
R Sanchez
Keyword(s):  
Escherichia Coli ◽  
Gene Product ◽  
Activity Ratio ◽  
Deae Cellulose ◽  
Trna Synthetase ◽  
Trna Synthetases ◽  
E Coli ◽  
Aminoacyl Trna Synthetases

In contrast with most aminoacyl-tRNA synthetases, the lysyl-tRNA synthetase of Escherichia coli is coded for by two genes, the normal lysS gene and the inducible lysU gene. During its purification from E. coli K12, lysyl-tRNA synthetase was monitored by its aminoacylation and adenosine(5′)tetraphospho(5′)adenosine (Ap4A) synthesis activities. Ap4A synthesis was measured by a new assay using DEAE-cellulose filters. The heterogeneity of lysyl-tRNA synthetase (LysRS) was revealed on hydroxyapatite; we focused on the first peak, LysRS1, because of its higher Ap4A/lysyl-tRNA activity ratio at that stage. Additional differences between LysRS1 and LysRS2 (major peak on hydroxyapatite) were collected. LysRS1 was eluted from phosphocellulose in the presence of the substrates, whereas LysRS2 was not. Phosphocellulose chromatography was used to show the increase of LysRS1 in cells submitted to heat shock. Also, the Mg2+ optimum in the Ap4A-synthesis reaction is much higher for LysRS1. LysRS1 showed a higher thermostability, which was specifically enhanced by Zn2+. These results in vivo and in vitro strongly suggest that LysRS1 is the heat-inducible lysU-gene product.

The Mechanism of Replication of Single-Stranded DNA. VI. Requirements for Ribonucleoside Triphosphates and DNA Polymerase III

1973 ◽  
Vol 51 (12) ◽  
pp. 1588-1597 ◽  
Author(s):  
David T. Denhardt ◽  
Makoto Iwaya ◽  
Grant McFadden ◽  
Gerald Schochetman
Keyword(s):  
Dna Polymerase ◽  
Dna Polymerases ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Dna Polymerase Iii ◽  
Single Stranded Dna ◽  
E Coli ◽  
Polymerase Iii

Evidence is presented that in Escherichia coli made permeable to nucleotides by exposure to toluene, the synthesis of a DNA chain complementary to the infecting single-stranded DNA of bacteriophage [Formula: see text] requires ATP as well as the four deoxyribonucleoside triphosphates. This synthesis results in the formation of the parental double-stranded replicative-form (RF) molecule. The ATP is not required simply to prevent degradation of the ribonucleoside or deoxyribonucleoside triphosphates; it can be partially substituted for by other ribonucleoside triphosphates.No single one of the known E. coli DNA polymerases appears to be uniquely responsible in vivo for the formation of the parental RF. Since [Formula: see text] replicates well in strains lacking all, or almost all, of the in-vitro activities of DNA polymerases I and II, neither of these two enzymes would seem essential; and in a temperature-sensitive E. coli mutant (dnaEts) deficient in DNA polmerase-I activity and possessing a temperature-sensitive DNA polymerase III, the viral single-stranded DNA is efficiently incorporated into an RF molecule at the restrictive temperature. In contrast, both RF replication and progeny single-stranded DNA synthesis are dependent upon DNA polymerase III activity.

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