Changes in the expression of key genes involved in the biosynthesis of menthol and menthofuran in <Emphasis Type="Italic">Mentha piperita</Emphasis> L. under drought stress

Peppermint (Mentha piperita) is known as an important medicinal plant throughout the world. In the present study, after exposing peppermint plants under drought stress, the qRT-PCR was use to analyze the expression of genes involved in menthol biosynthesis pathway and encoding: limonene synthase (lS), limon-3-hydroxylase (l3oh), trans-isopiperitenol dehydrogenase (ipd), isopiperitenone reductase (ipr), pulegone reductase (pr), menthol dehydrogenase (mdeh), and menthofuran synthase (mfs), which also evaluated the morphological and physiological traits. The results revealed that due to water stress, the gene expression levels of ipd, ipr, and mfs were increased, whereas the gene expression level of pr and mdeh was decreased under water stress conditions. The most of essential oil components (menthol, menthofuran, and plugene), which were analyzed by gas chromatography–mass spectrometry (GC–MS), was positively correlated with genes expression. Drought stress decreased morphological and induces increasing contents of pulegone and menthofuran and reduction in menthol percentages. Results from this study suggest that up-regulation of mfs might contribute to the altered of menthofuran as well as down-regulation of mdeh might cause the reduction of menthol. Furthermore, increasing ls gene expression levels might induce more essential oil yield, while reduction of mfs gene expression levels causes an improvement of essential oil quality.     

Gain-Assisted Propagation and Angular Response of Surface Plasmon Resonance in Nonlinear Kretschmann Configuration

The present study investigates the optical characteristics and angular response of gain-assisted surface plasmon resonance incorporating a nonlinear Kretschmann configuration. Nonlinear susceptibility of two-level atoms is used to describe the gain and nonlinear characteristics of amplifying medium. The structure is investigated and compared in both linear and nonlinear regimes. Our theory presents surface plasmon polaritons (SPPs) amplification accounting for saturation of linear gain by nonlinear losses. Reflectivity curve of the Kretschamnn configuration, attenuation constant, propagation length, and magnetic field intensity of plasmonic wave at the interface provide direct proofs of saturated gain induced by nonlinear absorption loss. Linear analysis predicts enhanced total reflection (ETR) in the presence of gain while in nonlinear regime, no ETR phenomenon occurs due to nonlinear loss absorption. Our analysis verifies that in the presence of nonlinear absorption loss, a saturation tendency of propagation length and plasmonic intensity is inevitable which is coincident with the practical observations.     

Analysis of Genetic Diversity of Chukar Partridge (Alectoris chukar) Populations in Khorasan-e-Razavi Province of Iran by RAPD-PCR

RAPD markers were used to investigate population genetic parameters of an endangered partridge, Alectoris chukar, in four areas of Iran, as a part of a genetic conservation program. The aim of this study was to analyze the genetic similarity among these populations. Blood samples from 75 birds were used for DNA extraction and RAPD-PCR analysis of 67 loci, with 28 polymorphic bands (41.79%). The populations of Kalat-e-Nader and Mashhad were found to be closely related, as were the Torbat-e-Jaam and the Quchan populations. Mean heterozygosity for all populations was 0.4405 ± 0.0755. The results indicate that chukar partridge genetic diversity in Khorasan-e-Razavi province is sufficient and the amount of gene flow among populations is acceptable.     

Multiple Manifold Clustering Using Curvature Constrained Path

The problem of multiple surface clustering is a challenging task, particularly when the surfaces intersect. Available methods such as Isomap fail to capture the true shape of the surface near by the intersection and result in incorrect clustering. The Isomap algorithm uses shortest path between points. The main draw back of the shortest path algorithm is due to the lack of curvature constrained where causes to have a path between points on different surfaces. In this paper we tackle this problem by imposing a curvature constraint to the shortest path algorithm used in Isomap. The algorithm chooses several landmark nodes at random and then checks whether there is a curvature constrained path between each landmark node and every other node in the neighborhood graph. We build a binary feature vector for each point where each entry represents the connectivity of that point to a particular landmark. Then the binary feature vectors could be used as a input of conventional clustering algorithm such as hierarchical clustering. We apply our method to simulated and some real datasets and show, it performs comparably to the best methods such as K-manifold and spectral multi-manifold clustering.     

Aminopropyl-functionalized cubic Ia3d mesoporous silica nanoparticle as an efficient support for immobilization of superoxide dismutase

In this research, the immobilization of superoxide dismutase (SOD) onto aminopropyl-functionalized KIT-6 [n-PrNH(2)-KIT-6] was investigated. This organo-functionalized mesoporous silica nanoparticle was prepared using a non-ionic surfactant and was fully characterized by XRD, nitrogen adsorption-desorption isotherm assay, IR and TGA techniques. An activity assay demonstrated that the immobilized SOD had a higher activity than the free enzyme. Further investigations using FT-IR, circular dichroism (CD), and probe 1-anilino-8-naphthalene sulfonate (ANS) fluorescence intensity measurements indicated that the structure of the enzyme did not change upon binding to the mesoporous silica, and that immobilized SOD was also less affected by higher temperatures. The melting temperatures of the free and immobilized enzymes were measured by differential scanning calorimetry (DSC), which showed that a fraction of immobilized enzyme was more stable and revealed that immobilized enzyme was partly reversible.     

Cyclic antimicrobial R-, W-rich peptides: the role of peptide structure and <Emphasis Type="Italic">E. coli</Emphasis> outer and inner membranes in activity and the mode of action

This study compares the effect of cyclic R-, W-rich peptides with variations in amino acid sequences and sizes from 5 to 12 residues upon Gram negative and Gram positive bacteria as well as outer membrane-deficient and LPS mutant Escherichia coli (E. coli) strains to analyze the structural determinants of peptide activity. Cyclo-RRRWFW (c-WFW) was the most active and E. coli-selective sequence and bactericidal at the minimal inhibitory concentration (MIC). Removal of the outer membrane distinctly reduced peptide activity and the complete smooth LPS was required for maximal activity. c-WFW efficiently permeabilised the outer membrane of E. coli and promoted outer membrane substrate transport. Isothermal titration calorimetric studies with lipid A-, rough-LPS (r-LPS)- and smooth-LPS (s-LPS)-doped POPC liposomes demonstrated the decisive role of O-antigen and outer core polysaccharides for peptide binding and partitioning. Peptide activity against the inner E. coli membrane (IM) was very low. Even at a peptide to lipid ratio of 8/1, c-WFW was not able to permeabilise a phosphatidylglycerol/phosphatidylethanolamine (POPG/POPE) bilayer. Low influx of propidium iodide (PI) into bacteria confirmed a low permeabilising ability of c-WFW against PE-rich membranes at the MIC. Whilst the peptide effect upon eukaryotic cells correlated with the amphipathicity and permeabilisation of neutral phosphatidylcholine bilayers, suggesting a membrane disturbing mode of action, membrane permeabilisation does not seem to be the dominating antimicrobial mechanism of c-WFW. Peptide interactions with the LPS sugar moieties certainly modulate the transport across the outer membrane and are the basis of the E. coli selectivity of this type of peptides.     

TRAILR1 (rs20576) and GRIA3 (rs12557782) are not associated with interferon-β response in multiple sclerosis patients

Molecular Biology Reports - Multiple sclerosis (MS) is an autoimmune-type inflammatory disorder in human central nervous system. Recombinant interferon beta (IFN-β) decreases the number of...