Assessment of Morpho-Physiological and Biochemical Responses of Perennial Ryegrass to Gamma-Aminobutyric Acid (GABA) Application Under Salinity Stress Using Multivariate Analyses Techniques

Journal of Plant Growth Regulation - Salinity stress is one of the most important global problems that afflicts and limits the growth and development of turfgrass in arid and semi-arid areas....     

The computer as a laboratory for the physical chemistry of membranes

A mini-review is given of some recent advances in the use of computer-simulation approaches to the study of physico-chemical properties of lipid bilayers and biological membranes. The simulations are based on microscopic molecular interaction models as well as random-surface models of fluid membranes. Particular emphasis is put on those properties that are controlled by the many-particle character of the lamellar membrane, i.e. correlations and fluctuations in density, composition and large-scale conformational structure. It is discussed how dynamic membrane heterogeneity arises and how it is affected by various molecular species interacting with membranes, such as cholesterol, drugs, insecticides, as well as polypeptides and integral membrane proteins. The influence of bending rigidity and osmotic-pressure gradients on large-scale membrane conformation and topology is described.     

Comparison of PCR-RFLP with 21-plex PCR and rDNA Sequencing for Identification of Clinical Yeast Isolates

Non-albicans Candida species and other rare yeasts have emerged as major opportunistic pathogens in fungal infections. Identification of opportunistic yeasts in developing countries is mainly performed by phenotypic assay, which are time-consuming and prone to errors. The aim of the present study was to evaluate PCR-RFLP as a routinely used identification technique for the most clinically important Candida species in Iran and make a comparison with a novel multiplex PCR, called 21-plex PCR. One hundred and seventy-three yeast isolates from clinical sources were selected and identified with sequence analysis of the D1/D2 domains of rDNA (LSU rDNA) sequencing as the gold standard method. The results were compared with those obtained by PCR-RFLP using MspI restriction enzyme and the 21-plex PCR. PCR-RFLP correctly identified 93.4% of common pathogenic Candida species (C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and P. kudriavsevii (=?C. krusei)) and was able to identify 45.5% of isolates of the uncommon yeast species compared to the D1/D2 rDNA sequencing. Compared with PCR-RFLP, all common Candida species and 72.7% of uncommon yeast species were correctly identified by the 21-plex PCR. The application of the 21-plex PCR assay as a non-sequence-based molecular method for the identification of common and rare yeasts can reduce turnaround time and costs for the identification of clinically important yeasts and can be applied in resource-limited settings.

     

Hydrogen dissociation on diene-functionalized carbon nanotubes

Chemical functionalization of a zigzag carbon nanotube (CNT) with 1, 3-cyclohexadiene (CHD), previously reported by experimentalists, has been investigated in the present study using density functional theory in terms of energetic, geometric, and electronic properties. Then, the thermodynamic and kinetic feasibility of H₂ dissociation on the pristine and functionalized CNTs have been compared. The dissociation energy of the H₂ molecule on the pristine and functionalized CNT has been calculated to be about ?1.00 and ?1.55 eV, while the barrier energy is found to be about 3.70 and 3.51 eV, respectively. Therefore, H₂ dissociation is thermodynamically more favorable on the CNT-CHD system than on the pristine tube, while the favorability of the dissociation on the pristine tube is higher in term of kinetics.     

Fluorination of BC3 nanotubes: DFT studies

We have studied the adsorption of atomic and molecular fluorines on a BC₃ nanotube by using density functional calculations. It was found that the adsorption of atomic fluorine on a C atom of the tube surface is energetically more favorable than that on a B atom by about 0.97 eV. The adsorption of atomic fluorine on both C and B atoms significantly affects the electronic properties of the BC₃ tube. The HOMO-LUMO energy gap is considerably reduced from 2.37 to 1.50 and 1.14 eV upon atomic F adsorption on B and C atoms, respectively. Molecular fluorine energetically tends to be dissociated on B atoms of the tube surface. The associative and dissociative adsorption energies of F₂ were calculated to be about ?0.42 and ?4.79 eV, respectively. Electron emission density from BC₃ nanotube surface will be increased upon both atomic and molecular fluorine adsorptions due to work function decrement.     

LED light mediates phenolic accumulation and enhances antioxidant activity in Melissa officinalis L. under drought stress condition

The popularity of lemon balm in conventional medicine is suggested by the existence of two groups of compounds, namely essential oil and phenylpropanoids pathway derivatives. One of the promising approaches to improve tolerance to drought stress induced oxidative damage in seedlings grown in greenhouses and plant growth chambers is replacing the traditional and high-cost light technologies by recently developed light emitting diodes (LED). In this experiment, we analyzed the role of various LED lights including red (R), blue (B), red (70%) + blue (30%) (RB), and white (W) as well as normal greenhouse light (as control) to stimulate defense mechanisms against drought stress in two genotypes of Melissa officinalis L. The present study demonstrates that pre-treatment with LEDs with high-intensity output for 4 weeks alleviated harmful effects of drought stress in the two genotypes. Under drought stress, RB LED pre-treated plantlets of the two genotypes exhibited the highest relative growth index of shoot and root and total phenolic and anthocyanin content compared to those irradiated with other LEDs and greenhouse lights. The highest amount of malondialdehyde level was detected in R LED exposed plants. In response to drought, LED-exposed plants especially RB light-irradiated plants of the two genotypes maintained significantly higher antioxidant and phenylalanine ammonia-lyase (PAL) enzyme activities and higher expression level of the PAL1 and 4CL-1 genes compared to those irradiated with greenhouse light. We concluded that RB LED light provides a better growth condition and resistance to drought stress for the two genotypes of lemon balm by the highest antioxidant activity and the least amount of damage to the cell membranes. Our data suggest that LED light pre-treatments as moderate stress activate antioxidant systems, enhance the scavenging of ROS and induce drought stress tolerance in the two genotypes of lemon balm plants.

     

Incorporation of SPION-casein core-shells into silk-fibroin nanofibers for cardiac tissue engineering

Mimicking the structure of extracellular matrix (ECM) of myocardium is necessary for fabrication of functional cardiac tissue. The superparamagnetic iron oxide nanoparticles (SPIONs, Fe₃O₄), as new generation of magnetic nanoparticles (NPs), are highly intended in biomedical studies. Here, SPION NPs (1 wt%) were synthesized and incorporated into silk-fibroin (SF) electrospun nanofibers to enhance mechanical properties and topography of the scaffolds. Then, the mouse embryonic cardiac cells (ECCs) were seeded on the scaffolds for in vitro studies. The SPION NPs were studied by scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM). SF nanofibers were characterized after incorporation of SPIONs by SEM, TEM, water contact angle measurement, and tensile test. Furthermore, cytocompatibility of scaffolds was confirmed by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. SEM images showed that ECCs attached to the scaffolds with elongated morphologies. Also, the real-time PCR and immunostaining studies approved upregulation of cardiac functional genes in ECCs seeded on the SF/SPION-casein scaffolds including GATA-4, cardiac troponin T, Nkx 2.5, and alpha-myosin heavy chain, compared with the ones in SF. In conclusion, incorporation of core-shells in SF supports cardiac differentiation, while has no negative impact on ECCs' proliferation and self-renewal capacity.     

Modulatory effects of statins on the autophagy: A therapeutic perspective

Autophagy is considered as an important mechanism for maintaining homeostasis and responsible for the degradation of superfluous or potentially toxic components and organelles. Autophagy impairment is associated with a number of pathological conditions, such as aging, neurological disorders, cancer, and infection. Autophagy also plays a significant role in cancer chemotherapy. The multiple cancer drugs have been notably developed with the strategy of autophagy modulation. Statins, 3-hydroxy-3-methyl-glutaryl-CoA inhibitors, are known due to their efficacy in decreasing low-density lipoprotein and extensively used for the management of cardiovascular diseases. Statins have other therapeutic and biological activities, such as antioxidant, anti-inflammatory, antitumor, and neuroprotective known as pleiotropic effects. It seems that statins are capable of targeting various signaling pathways in the induction of their great pharmacological effects. At the present study, we demonstrate the therapeutic effects of statins mediated via autophagy regulation.     

Nanoparticles and cancer therapy: Perspectives for application of nanoparticles in the treatment of cancers

Rapid growth in nanotechnology toward the development of nanomedicine agents holds massive promise to improve therapeutic approaches against cancer. Nanomedicine products represent an opportunity to achieve sophisticated targeting strategies and multifunctionality. Nowadays, nanoparticles (NPs) have multiple applications in different branches of science. In recent years, NPs have repetitively been reported to play a significant role in modern medicine. They have been analyzed for different clinical applications, such as drug carriers, gene delivery to tumors, and contrast agents in imaging. A wide range of nanomaterials based on organic, inorganic, lipid, or glycan compounds, as well as on synthetic polymers has been utilized for the development and improvement of new cancer therapeutics. In this study, we discuss the role of NPs in treating cancer among different drug delivery methods for cancer therapy.     

An electrochemical biosensor for 3-hydroxybutyrate detection based on screen-printed electrode modified by coenzyme functionalized carbon nanotubes

3-Hydroxybutyrate, one of the main blood ketone bodies, has been considered as a critical indicator for diagnosis of diabetic ketoacidosis. Biosensors designed for detection of 3-hydroxybutyrate with advantages of precision, easiness and speedy performance have attracted increasing attention. This study attempted to develop a 3-hydroxybutyrate dehydrogenase-based biosensor in which single-walled carbon nanotubes (SWCNT) was used in order to immobilize the cofactor, NAD⁺, on the surface of screen-printed electrode. The formation of NAD⁺–SWCNT conjugates was assessed by electrochemistry and electron microscopy. Cyclic voltammetry was used to analyze the performance of this biosensor electrochemically. The considerable shelf life and reliability of the proposed biosensor to analyze real sample was confirmed by this method. The reduction in the over potential of electrochemical oxidation of NADH to ?0.15 V can be mentioned as a prominent feature of this biosensor. This biosensor can detect 3-hydroxybutyrate in the linear range of 0.01–0.1 mM with the low detection limit of 0.009 mM. Simultaneous application of screen-printed electrode and SWCNT has made the biosensor distinguished which can open new prospects for detection of other clinically significant metabolites.