Synthesis and characterization of gold nanoparticles

Gold nanoparticles (AuNPs) find a number of applications in many fields of electronics, catalysis, optics and biomedicine. This work reports a robust, fast and easy synthesis protocol, based on the Turkevich method to obtain AuNPs. Simple characterization techniques based on UV-Vis spectroscopy and transmission electronic microscopy are also reported. The resulting AuNPs presents properties at a nanometric scale, high purity and they may find potential uses in the treatment of cancer, antiviral and antibacterial agents and biosensors among others.

Chilean Rhubarb, Gunnera tinctoria (Molina) Mirb. (Gunneraceae): UHPLC-ESI-Orbitrap-MS Profiling of Aqueous Extract and its Anti-Helicobacter pylori Activity

The full UHPLC-MS metabolome fingerprinting and anti-Helicobacter pylori effect of Gunnera tinctoria (Molina) Mirb. (Nalca) total extract (GTE) and fractions prepared from its edible fresh petioles were evaluated. The activity of G. tinctoria against H. pylori strains ATCC 45504 and J99 was assessed in vitro by means of agar diffusion assay, Minimum Inhibition Concentration (MIC), and Minimum Bactericidal Concentration (MBC), while killing curve and transmission electronic microscopy (TEM) were conducted in order to determine the effect of the plant extract on bacterial growth and ultrastructure. Additionally, the inhibitory effect upon urease was evaluated using both the Jack Bean and H. pylori enzymes. To determine which molecules could be responsible for the antibacterial effects, tentative identification was done by ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-Q-Orbitrap®-HR-MS). Furthermore, the total G. tinctoria extract was fractionated using centrifugal partition chromatography (CPC), giving four active fractions (1–4). It was determined that the crude extract and centrifugal partition chromatography fractions of G. tinctoria have a bactericidal effect being the lowest MIC and MBC = 32 μg/ml. In the killing curves, fraction one acts faster than control amoxicillin. In the urease assay, F3 exhibited the lowest IC50 value of 13.5 μg/ml. Transmission electronic microscopy showed that crude G. tinctoria extract promotes disruption and separation of the cellular wall and outer membrane detachment on H. pylori causing bacterial cell death.

Boothiomyces angulosus and Boothiomyces elyensis: two new combinations in the Terramycetaceae (Rhizophydiales, Chytridiomycota)

The genus Rhizophydium was proposed by A. Schenk in 1858 to accommodate the inoperculate taxa previously placed in Chytridium. The morphological delineation encompassed around 235 species that have now been segregated into different genera based on molecular and zoospore ultrastructural analyses. However, some taxa have never been investigated for phylogenetic position or zoospore ultrastructural characters. The aim of this study was to use morphology, zoospore ultrastructure and molecular analyses to verify the placement of our isolates of Rhizophydium angulosum and R. elyense in the Rhizophydiales phylogeny. These isolates produced angular zoosporangia, characteristic of Terramycetaceae representatives, and grouped within the Boothiomyces clade in analyses of complete ITS and partial LSU regions of rDNA. Transmission electronic microscopy (TEM) analysis revealed that R. angulosum produces zoospores with the same ultrastructural characters described from Boothiomyces representatives. In addition, R. elyense presented sufficient characteristics that support its morphological delineation from Boothiomyces macroporosus, the type species of the genus. Based on molecular, morphological, and ultrastructural analyses, we transfer R. angulosum and R. elyense to Boothiomyces.

Attenuation of Low Ambient Temperature-Induced Myocardial Hypertrophy by Atorvastatin via Promoting Bcl-2 Expression

Background/Aims: It is well documented that myocardial hypertrophy is associated with low ambient temperature. Atorvastatin (Atv) has been shown to protect against atherosclerosis, cardiac fibrosis, ischemia/reperfusion injury, etc. In this study, we aim to determine whether atorvastatin is effective in the treatment of myocardial hypertrophy induced by cold exposure and to shed light on underlying mechanism. Methods: The mice aged 4-week were randomized to Control (Ctl) group (raised at room temperature), Cold group (raised at 3-5ºC) and Atv treatment group (raised at 3-5ºC followed by 10mg/kg/day Atv infusion). Echocardiography (ECG), HE, TUNEL and Masson’s trichrome staining, and Transmission electronic microscopy were performed to analyze cardiac function, myocardial hypertrophy, cardiac fibrosis, apoptosis and cardiomyocyte ultrastructure, respectively. Western blot was carried out to determine the involvement of MAPK and apoptosis pathways. Results: Exposure of mice to low temperature induced myocardial hypertrophic growth characterized by the elevation of heart/body weight index and heart weight /tibia length index, compared with control mice. Atv treatment attenuated cardiac hypertrophy induced by cold exposure; Atv also attenuated the increase of cross-sectional area of cardiomyocytes and cardiac collagen content fraction in mice exposed to cold. ECG showed that the decline of cardiac functions including the elevated left ventricular systolic/diastolic internal dimension (LVIDs/d) and fractional shortening (FS) in mice with cold exposure was also inhibited by Atv treatment. Transmission electronic microscopy uncovered that Atv attenuated mitochondrial injury induced by cold exposure in mice. In addition, systolic blood pressure was gradually increased in mice exposed to cold temperature, and Atv treatment significantly inhibited the elevation of blood pressure in cold-treated mice. Mechanistically, mitogen-activated protein kinase (MAPK) signal was not altered in mice exposed to cold, and Atv did not affect MAPK signal in cold-treated mice. But Atv mitigated the reduction of Bcl-2/Bax level in heart of cold-treated mice. Conclusion: Atv attenuated myocardial hypertrophy induced by cold exposure through inhibiting the downregulation of Bcl-2 in heart. It may provide a novel strategy for low temperature-induced myocardial hypertrophy treatment.