NaCl-induced changes in protoplasmic characteristics of Hordeum vulgare cultivars differing in salt tolerance

Water permeability and cytoplasmic viscosity and streaming were investigated in seedlings of two Hordeum vulgare cultivars differing in salt tolerance. Six-day-old seedlings were grown for 4 additional days in Hoagland solution with and without 100 m M NaCl added.
Observations and measurements were made in subepidermal cells of the coleoptile using plasmolytic and centrifugation methods and recordings of the speed of movement of microsomes.
Water permeability was about the same in controls of both cultivars, and was decreased by NaCl stress, but decreased less in the tolerant cultivar. Cells from control plants of the stress tolerant variety had a higher cytoplasmic viscosity than cells from the moderately sensitive cultivar. Cytoplasmic viscosity in both cultivars decreased due to NaCl stress, and more so in the sensitive one. Cytoplasmic streaming was faster in the controls of the salt sensitive cultivar than in controls of the salt tolerant cultivar; NaCl had no significant effect on cytoplasmic streaming in both cultivars.
The specific responses of the cytoplasm of the sensitive and tolerant cultivars to the salt treatment reflect differences in its structure and composition. These differences in the cytoplasm already exist before exposure to salt stress but some alterations of cytoplasmic parameters (e.g. water permeability) were induced by the saline environment.     

Chemical Composition and Cytotoxic Activity of Eucalyptus torquata Luehm. and Eucalyptus salmonophloia F. Muell. Trunk Bark Essential Oils against Human SW620 and MDA-MB-231 Cancer Cell Lines

In recent years, there has been a growing interest in the screening of natural active ingredients from Eucalyptus essential oils because of their evident importance in practical utility and their undeniable therapeutic properties. Based on this, the aim of the present study was to investigate the chemical profile of the essential oils of the trunk bark of Eucalyptus torquata Luehm. (ETEO), and E. salmonophloia F. Muell. (ESEO), growing in Tunisia. The in vitro cytotoxic properties of the extracted EOs were also evaluated against two human cancer cell lines: breast carcinoma cell lines MDA-MB-231 and colorectal cancer cell lines SW620. The analysis by gas chromatography coupled with mass spectrometry (GC/MS) led to the identification of 32 compounds from the ETEO, with the dominant constituents being the monoterpenes trans-myrtanol (73.4 %) and myrtenol (4.7 %), and the apocarotene (E)-β-ionone (3.9 %). In the case of ESEO, 29 compounds were identified with trans-myrtanol (25.0 %), decanoic acid (22.1 %), nonanoic acid (9.8 %), γ-elemene (6.5 %), γ-maaliene (5.5 %), and α-terpineol (5.3 %) as the main components. The cytotoxicity of EOs against the two chosen cell lines was tested using Crystal Violet Staining (CVS) assay and 5-fluorouracil as a reference drug. The two EOs exhibited a significant dose-dependent inhibition against the viability of the used cell lines. Their inhibitory effects were particularly observed towards SW620 colon carcinoma cells with IC₅₀ values of 26.71±1.22 and 22.21±0.85 μg/mL, respectively, indicating that both oils were more cytotoxic for SW620 cells compared to MDA-MB-231 one.     

Prediction of chlortetracycline adsorption on the Fe3O4 nanoparticle using molecular dynamics simulation

Abstract

Molecular dynamics (MD) simulation was applied to investigate the adsorption mechanism of chlortetracycline (CTC) antibiotic molecule as the aqueous pollutant on the Fe₃O₄ nanoparticle (NP). Two different NP sizes with a diameter of about 1.4?nm and 3.5?nm were selected. Initially, the stability of both NPs in water was investigated by calculating radial distribution function curves of NP atoms. Simulation results confirmed the stable crystallographic structures of both NPs. However, small NP induce greater structural stabilization. Then, CTC molecules were adsorbed on NPs surface in various pollutant concentrations. Electrostatic and hydrogen bond were the major types of interactions between CTC molecules and the adsorbent surface. CTC molecules formed a complex with NP surface from their amine side chains; while they were parallel to each other in their aromatic rings and π-π bond between two CTC molecules was formed. Diffusion rate of CTC molecules could predict the adsorption mechanism. At lower concentration of CTC, CTC molecules tend to adsorb on the NP surface. At these concentrations, the diffusion rate of CTC was high. By increasing the CTC concentration, the pollutant agglomeration was enhanced which decreased the diffusion rate. At this time, the surface of NP was saturated. In addition, the results of isotherm curves showed that CTC adsorption on small NPs could be defined with both Langmuir and Freundlich isotherm models, while Freundlich isotherm model was more appropriate for larger NPs. In conclusion, observations confirmed that MD simulation could successfully predict the behavior of CTC adsorption on the Fe₃O₄ NP surface.

Communicated by Ramaswamy H. Sarma     

Synthesis of Some Pyridine Ribosides and Their Biological Activity

Abstract

A synthesis of 1-(β-D-ribofuranosyl)-pyridin-2-thiones via reaction of 3-cyanopyridin-2(H)-thiones with 2,3,5-tri-O-benzoyl-D-ribofuranosyl bromide under basic conditions, followed by hydrolysis with methanolic ammonia is reported.     

MNPs-IHSPN nanoparticles in multi-application with absorption of bio drugs in vitro

The aim of this project is to investigate the method of using a common buffer to determine the degree of stabilization and secretion of two drug molecules that have been analyzed in vitro. First, magnetic nanoparticles were synthesized and their structure was identified by instruments such as XPS (X-ray photoelectron spectroscopy) and FT-IR (Fourier transform infrared spectroscopy). The main purpose of this study was to investigate the stabilization and release of methotrexate on the surface of magnetic nanoparticles. The two temperatures were 37 and 25°, respectively. After reaction with the biomolecules, the adsorption rate for both drug molecules was about 60–80. PBS buffer was also used for diffusion of biomolecules and the results were analyzed by spectrophotometer analysis. With these results, the adsorption of cysteine and MTX was more than 60% and its release rate in MNPS-IHSPN was up to 90%, which means that high-strength stabilization and release by magnetic nanoparticles under external magnetic field and in vitro confirmed. The result of this project for the exchange of drugs by the surface of magnetic nanoparticles to repair damaged cells in the body of living organisms can be generalized.     

Flavonoids of three local Senecio species

Two isorhamnetin glycosides and two sulphated derivatives are reported for the first time in the genus Senecio.