Proline-Functionalized Graphene Oxide Nanoparticles (GO–Pro NPs) Mitigate Salt-Induced Adverse Effects on Morpho-Physiological Traits and Essential Oils Constituents in Moldavian Balm (Dracocephalum moldavica L.)

Many methodologies have been established to lessen negative impacts of salinity on plants. Of those methodologies, nanoparticles (NPs) application has achieved great importance thanks to their unique physico-chemical properties. Consequently, formerly respecting encouraging impacts of graphene oxide (GO) and proline (Pro) on different plant processes under non-stress and stress conditions, proline-functionalized graphene oxide nanoparticles “GO–Pro NPs” were synthesized and characterized. Graphite powder, as starting material, was used to synthesize GO using modified Hummers method followed by functionalization of its surface by proline in basic media. Afterward, GO–Pro NPs, GO and Pro, each at 0, 50 and 100 mg L^?1 concentrations with three replications, were applied on Moldavian balm (Dracocephalum moldavica L.) plants to assay their effects under non-stress (0 mM) and salt stress (50 and 100 mM) conditions. GO–Pro NPs and Pro effectively alleviated negative effects of salinity through increasing morphological parameters, photosynthetic pigments, chlorophyll fluorescence parameters, chlorophyll index (SPAD), and membrane stability index (MSI) and decreasing hydrogen peroxide and malondialdehyde, as well. Also application of GO–Pro NPs enhanced proline, antioxidant enzymes activities, and most dominant constituents of essential oil. The highest MSI (48.87%) and proline content (15.36 µM g^?1 FW) were observed in plant treated with GO–Pro NPs (50 mg L^?1) under 100 mM NaCl salinity stress. The GO–Pro NPs treatment at lower dose (50 mg L^?1) could be introduced as the best preservative treatment for Moldavian balm under salt stress. GO application mostly had no effect on the measured parameters announcing it as carrier for Pro to enhance its efficiency. In conclusion, GO–Pro NPs application could promote Moldavian balm performance and essential oil under salinity presenting GO–Pro NPs as new treatment against stress conditions.

     

Immunomodulatory agents for COVID-19 treatment: possible mechanism of action and immunopathology features

Molecular and Cellular Biochemistry - The novel coronavirus pandemic has emerged as one of the significant medical-health challenges of the current century. The World Health Organization has named...     

The relation of omentin gene expression and glucose homeostasis of visceral and subcutaneous adipose tissues in non-diabetic adults

Molecular Biology Reports - Adipose tissue (AT) is a passive reservoir for energy storage and an active endocrine organ responsible for synthesizing bioactive molecules called...     

First volumetric records of airborne Cladosporium and Alternaria spores in the atmosphere of Al Khor (northern Qatar): a preliminary survey

Aerobiologia - Daily monitoring of airborne fungal spores was carried out for the first time in Al Khor city, Qatar, using a Hirst type 7-day recording volumetric spore trap, from May 2017 to May...     

A surface acoustic wave sensor functionalized with a polypyrrole molecularly imprinted polymer for selective dopamine detection

A surface acoustic wave sensor operating at 104 MHz and functionalized with a polypyrrole molecularly imprinted polymer has been designed for selective detection of dopamine (DA). Optimization of pyrrole/DA ratio, polymerization and immersion times permitted to obtain a highly selective sensor, which has a sensitivity of 0.55°/mM (≈550 Hz/mM) and a detection limit of ≈ 10 nM. Morphology and related roughness parameters of molecularly imprinted polymer surfaces, before and after extraction of DA, as well as that of the non imprinted polymer were characterized by atomic force microscopy. The developed chemosensor selectively recognized dopamine over the structurally similar compound 4‐hydroxyphenethylamine (referred as tyramine), or ascorbic acid,which co‐exists with DA in body fluids at a much higher concentration. Selectivity tests were also carried out with dihydroxybenzene, for which an unexpected phase variation of order of 75% of the DA one was observed. Quantum chemical calculations, based on the density functional theory, were carried out to determine the nature of interactions between each analyte and the PPy matrix and the DA imprinted PPy polypyrrole sensing layer in order to account for the important phase variation observed during dihydroxybenzene injection. Copyright © 2015 John Wiley & Sons, Ltd.     

First efficient CRISPR‐Cas9‐mediated genome editing in Leishmania parasites

Protozoan pathogens that cause leishmaniasis in humans are relatively refractory to genetic manipulation. In this work, we implemented the CRISPR‐Cas9 system in Leishmania parasites and demonstrated its efficient use for genome editing. The Cas9 endonuclease was expressed under the control of the Dihydrofolate Reductase‐Thymidylate Synthase (DHFR‐TS) promoter and the single guide RNA was produced under the control of the U6snRNA promoter and terminator. As a proof of concept, we chose to knockout a tandemly repeated gene family, the paraflagellar rod‐2 locus. We were able to obtain null mutants in a single round of transfection. In addition, we confirmed the absence of off‐target editions by whole genome sequencing of two independent clones. Our work demonstrates that CRISPR‐Cas9‐mediated gene knockout represents a major improvement in comparison with existing methods. Beyond gene knockout, this genome editing tool opens avenues for a multitude of functional studies to speed up research on leishmaniasis.