Groups Of Na Research Articles

Montmorillonite nanoclay based formulation for controlled and selective release of volatile essential oil compounds

In the current study, a green method that can be easily used in different industrial applications, based on the modification of sodium exchanged montmorillonite (Na+-Mt) with essential oils (EO) such as thyme oil, thymol and carvacrol was presented. The obtained results show the prepared clays-essential oils hybrids were promising nanomaterials to encapsulate the active compounds and to control their release selectively in the functional applications. X-ray diffraction (XRD) analysis was used to study the adsorption of EO, thymol and carvacrol molecules, in the interlayer space. To verify the adsorption of thyme EO, thymol and carvacrol into Na+-Mt layers and to determine the temperature range where the EO, thymol and carvacrol release took place, thermogravimetric analysis (TG) was used. Attenuated total reflecting-Fourier-transform infrared (ATR-FTIR) spectroscopy was used to verify and to study the adsorption mechanism. The obtained results show that the interlayer space of Na+-Mt was not affected by the adsorption of thyme EO, thymol or carvacrol molecules. The release of the adsorbed molecules of thyme EO, thymol or carvacrol from Na+-Mt surface was obtained above 180 °C. Combination of simulation with all obtained experimental results, confirm that the adsorption process of thyme EO, thymol, and carvacrol molecules on the Na+-Mt took place on the external surface i) by hydrogen bonds between the OH groups of thyme EO, thymol or carvacrol molecules and OH groups of Na+-Mt surface, and ii) by hydrogen bonds between these adsorbed molecules. The release study shows that the adsorption of EO like thyme, and its constituents such as thymol and carvacrol onto an inorganic porous material such as Na+-Mt provides extended controlled release of all adsorbed active molecules with their chemical stability due to the protection against environmental conditions. In addition, the release of thyme oil constituents (like thymol and carvacrol) occurs by a selective process in time.

Development of a duplex TaqMan real-time RT-PCR assay for simultaneous detection of newly emerged H5N6 influenza viruses

BackgroundIn 2017–2018, a new highly pathogenic H5N6 avian influenza virus (AIV) variant appeared in poultry and wild birds in Asian and European countries and caused multiple outbreaks. These variant strains are different from the H5N6 virus associated with human infection in previous years, and their genetic taxonomic status and antigenicity have changed. Therefore, revision of the primers and probes of fluorescent RT-PCR is important to detect the new H5N6 subtype AIV in poultry and reduce the risk of an epidemic in birds or humans.MethodsIn this study, the primers and probes including three groups of HA and four groups of NA for H5N6 influenza virus were evaluated. Then a set of ideal primer and probes were selected to further optimize the reaction system and established a method of double rRT-PCR assay. The specificity of this method was determined by using H1~H16 subtype AIV.ResultsThe results showed that fluorescence signals were obtained for H5 virus in FAM channel and N6 virus in VIC channel, and no fluorescent signal was observed in other subtypes of avian influenza viruses. The detection limit of this assay was 69 copies for H5 and 83 copies for N6 gene. And, the variability tests of intra- and inter-assay showed excellent reproducibility. Moreover, this assay showed 100% agreement with virus isolation method in detecting samples from poultry.ConclusionThe duplex rRT-PCR assay presented here has high specificity, sensitivity and reproducibility, and can be used for laboratory surveillance and rapid diagnosis of newly emerged H5N6 subtype avian influenza viruses.

Mercury Toxicity on Sodium Pump and Organoseleniums Intervention: A Paradox

Mercury is an environmental poison, and the damage to living system is generally severe. The severity of mercury poisoning is consequent from the fact that it targets the thiol-containing enzymes, irreversibly oxidizing their critical thiol groups, consequently leading to an inactivation of the enzyme. The Na+/K+-ATPase is a sulfhydryl protein that is sensitive to Hg2+ assault. On the other hand, organoseleniums are a class of pharmacologically promising compounds with potent antioxidant effects. While Hg2+ oxidizes sulfhydryl groups of Na+/K+-ATPase under in vitro and in vivo conditions, the organoselenium compounds inhibit Na+/K+-ATPase in vitro but enhance its activities under in vivo conditions with concomitant increase in the level of endogenous thiols. Paradoxically, it appears that these two thiol oxidants can be used to counteract one another under in vivo conditions, and this hypothesis serves as the basis for this paper.

Voltage-gated sodium channels are targets for toxins from the venom of the spider Heriaeus melloteei

Three novel peptides were isolated from the venom of the spider Heriaeus melloteei (Thomisidae) and characterized. The peptides named Hm-1, 2 and 3 blocked voltage-gated Na+ channels at concentrations in the order of 100 nM. Activity of the purified peptides was investigated in Na+ channel isoforms of mammals and insects. Hm-1 and 2 appeared to act as pore blockers, whereas Hm-3 modulated the channel activation process. The toxins described exhibit minor similarity with other known peptides and may therefore constitute new groups of Na+ channel ligands.

Two types of cone bipolar cells express voltage-gated Na+ channels in the rat retina.

Two groups of retinal cone bipolar cells (CBCs) in rats were found to express voltage-gated Na+ channels. The axon terminals of the first group stratify in sublamina 2 of the inner plexiform layer (IPL) and partially overlap with the OFF-cholinergic band. This group was identified as type 3 CBCs. The axon terminals of the second group stratify in sublamina 3 of the IPL, slightly distal to the ON-cholinergic band. Cells of this second group resemble type 5 CBCs. In addition, we observed another group of ON-type CBCs with terminal stratification similar to that of the second group. However, this latter group did not show any Na+ current, instead exhibiting a large hyperpolarization-activated cyclic nucleotide-gated cation current, suggesting the existence of two subclasses of physiologically distinct type 5 CBCs. Both groups of Na+-expressing bipolar cells were capable of generating a rapid tetrodotoxin-sensitive action potential as revealed by current injection. Multiple spike-like potentials were also observed in some of these cells. Results of this study provide valuable insights into the function of voltage-gated Na+ channels of retinal bipolar cells in retinal processing.

In situ synthesis of silica gelnanowire/Na+–montmorillonite nanocomposites by the sol–gel route

Silica-gel nanowire/Na+–montmorillonite (Na+–MMT) nanocomposites were prepared by the in situ sol–gelprocess of tetraethyl orthosilicate (TEOS) in the presence ofNa+–MMT and ammonia as catalyst. Microstructure characterization ofthe nanocomposites was done by SEM, TEM, EDX, XRD and FTIR.It was found that a lot of silica-gel nanowires grew along the edges ofNa+–MMT. The combination between the nanowires andNa+–MMT was accomplished via polycondensation of the hydrolyzed TEOS and the edge –OH groups ofNa+–MMT.