Ordering Dynamics in Neuron Activity Pattern Model: An Insight to Brain Functionality

We study the domain ordering kinetics in d = 2 ferromagnets which corresponds to populated neuron activities with both long-ranged interactions, V(r) ∼ r⁻ⁿ and short-ranged interactions. We present the results from comprehensive Monte Carlo (MC) simulations for the nonconserved Ising model with n ≥ 2, interaction range considering near and far neighbors. Our model results could represent the long-ranged neuron kinetics (n ≤ 4) in consistent with the same dynamical behaviour of short-ranged case (n ≥ 4) at far below and near criticality. We found that emergence of fast and slow kinetics of long and short ranged case could imitate the formation of connections among near and distant neurons. The calculated characteristic length scale in long-ranged interaction is found to be n independent (L(t) ∼ t^1/(n−2)), whereas short-ranged interaction follows L(t) ∼ t^1/2 law and approximately preserve universality in domain kinetics. Further, we did the comparative study of phase ordering near the critical temperature which follows different behaviours of domain ordering near and far critical temperature but follows universal scaling law.     

From Dioxygen Storing to Dioxygen Sensing with Neuroglobins: An Insight from Molecular Mechanics

This work deals with two neuroglobins from phylogenetically distant organisms. Deriving from the acoelomorph Symsagittifera roscoffensis, SrNgb is functionally pentacoordinated, and is assumed to function as a reserve of dioxygen (O₂). Obtained from mice, mNgb is functionally hexacoordinated, and presumably triggers signals from sensing O₂. Here, it is investigated how these two globins are permeated by diatomic gases, SrNgb by O₂ and mNgb by CO. With protein atomic coordinates available from high‐resolution X‐ray diffraction analysis, O₂ and CO pathways were traced from molecular‐dynamics simulations in H₂O solution, which makes no difference between the two gases, accelerated by applying an external randomly‐oriented minimal force to the center of mass of the diatomic gas molecule. This allowed us to explore a statistically significant large number of trajectories. It emerged that CO leaves mNgb from preferentially peripheral gates located on the side of the heme propionate chains, whereas O₂ leaves SrNgb from the opposite side. This shows no analogy with either the functionally pentacoordinated, O₂‐transporting, myoglobin (Mgb), or the hexacoordinated, O₂‐sensing, cytoglobin, despite the same three‐over‐three typical α‐helical globin folding. The sole analogy that could be observed was a preference for the shortest diatomic gas pathways with both SrNgb and Mgb. It is tempting to speculate that this fulfills the need of being quick in delivering O₂ to depleted organs.     

Phylogenetic Affinities of Indian Apple Snails: An Insight into the Tibetan Tectonic Terranes

Gastropods belong to a hyper-diverse clade of molluscs and encompass limpets, slugs and snails. Interestingly, gastropods have effectively colonized land, freshwaters and marine habitats. However, the relationships among and within its constituent taxa remained in flux for decades due to delimitation in their morphological and anatomical features and hence molecular approach has taken a lead. An understanding into the history of Tibetan tectonic terranes is attempted in this article to derive through the phylogeny of Pila. In our study, we have re-evaluated the relationships within Ampullariidae by collecting the species of Pila globosa and Pila virens (India) and analyzed them comparing with 18S rDNA sequences from public domain. Obtained sequences are evaluated through Maximum Likelihood method in MEGA v 5 which clearly established a single cluster for the three individual taxons namely P. globosa with high bootstrap support. Pila virens showed a paraphyletic cluster with Pila ovata. A low bootstrap value of a few species of Pila possibly inferred rapid speciation among them. The novel observation in the present study is that P. virens forming a secondary cluster with the species from Vietnam namely Pila polita, Pila conica and Pila ampullacea has authenticated that the south India and Vietnam are in the same latitude namely 9–20°N, supporting the paleomagnetic data which unravelled that India collided with Asia around 57 mya in the Coenozoic era, whereas ampullariids must have been in co-existence since the Cambrian Period indicating their long evolutionary affinity and zoo-geographical relationship.     

An Insight into the Role of Glycerol in Chitosan Films

This work was focused on assessing the influence of the glycerol in chitosan matrices, analyzing the changes produced in the molecular mobility, mechanical, thermal, barrier and structural properties. The addition of glycerol in the matrix decreased the stress values, increasing the elasticity and water vapor permeability of the films, with a marked decrease in glass transition temperature; Detailed analyses of Fourier Transform IR Spectroscopy spectra supported the observed changes, especially in the spectral windows 1700–1500 cm^?1 revealing the modifications at molecular level caused by hydrogen bond interactions between chitosan and water in the presence of glycerol. Positron annihilation spectroscopic (PALS) measurements allowed determining the free volume assuming spherical holes as well as monitoring the structural changes in chitosan films caused by the addition of both, glycerol and water molecules. It was possible to infer that for unplasticized matrices, a sustained increase of the radius between 0.06 and 0.2 of X_water was observed, followed by a plateau up to 0.35. In the other case, with the addition of glycerol, there were two plateaus, the first between 0.25 and 0.37 of X_water, and the second from 0.41 to 0.47. For higher glycerol concentrations, the plasticizer would be mainly bounded to the chitosan pack more efficiently and the water present in the system would be predominantly free in the matrix causing its swelling. Findings on molecular mobility contributed to the understanding of the role of water and glycerol in the structural arrangement and its influence on film properties.     

An Insight for Potent In-Vitro Antioxidant Status of Short-Chain Peptides

International Journal of Peptide Research and Therapeutics - Peptides test drug 1, 2, 3 and 4 coded as RK, KH, RRH, and RRK were subjected to in-vitro antioxidant screening methods for the...     

A Homochiral Diphenylalanine Analog Based Mechanoresponsive Hydrogel: An Insight Towards Its Wound Healing Efficacy

Deciphering the most promising strategy for the evolution of potential wound-healing therapeutics is one of the greatest challenging affairs to date. The development of peptide-based smart scaffolds with innate antimicrobial, anti-inflammatory, and antioxidant properties is an appealing way out. Aligned to the goal a set of Hydrogelators I–IV were developed utilizing the concept of chiral orchestration in diphenylalanine fragment, such that the most potent construct with all the bench marks namely mechanoresponsiveness, biocompatibility, consistent antimicrobial and antioxidant properties, could be fished out from the design. Interestingly, our in vitro Antifungal and Lipid peroxidation analysis identified the homochiral isomer Boc-δ-Ava-L-Phe-L-Phe-OH (Hydrogelator I ), as an ideal candidate for the wound healing experiment, so we proceeded for the in vivo histopathological and antioxidant measurements in Wister rats. Indeed the wound images obtained from the different sets of animals on the 14^th day of treatment demonstrated that with increased recovery time, hydrogelator I displayed a significant reduction in the lesion diameter compared to the marketed drug, and negative control. Even the histopathological measurements using H & E staining demonstrated diminished tissue destruction, neutrophil infiltration necrosis, and lymphatic proliferation in the hydrogelators, in comparison to others, backed by in vivo lipid peroxidation data. Overall our investigation certifies hydrogelator I as an effective therapeutic for managing the wound healing complication.     

Spectroscopic Insight into Li‐Ion Batteries during Operation: An Alternative Infrared Approach

Multiple‐internal‐reflection infrared spectroscopy allows for the study of thin‐film amorphous silicon electrodes in situ and in operando, in conditions typical of those used in Li‐ion batteries. It brings an enhanced sensitivity, and the attenuated‐total‐reflection geometry allows for the extraction of quantitative information. When electrodes are cycled in representative electrolytes, the simultaneously recorded infrared spectra give an insight into the solid/electrolyte interphase (SEI) composition. They also unravel the dynamic behavior of this SEI layer by quantitatively assessing its thickness, which increases during silicon lithiation and partially decreases during delithiation. Li‐ion solvation effects in the vicinity of the electrode indicate that lithium incorporation in the solid phase is the rate‐determining step of the electrochemical processes during lithiation. The lithiation of the active material also results in the irreversible consumption of a large quantity of hydrogen in the pristine material. Finally, the evolution of the electronic absorption of the electrode material suggests that lithium diffusion is much easier after the first lithiation than in the pristine material. Therefore, in situ Fourier‐transform infrared spectroscopy performed in a well‐suited configuration efficiently extracts original and quantitative pieces of information on the surface and bulk phenomena affecting Li‐ion electrodes during their operation in realistic conditions.     

An Insight to Chiral Monolith for Enantioselective Nano and Micro HPLC: Preparation and Applications

This review gives an overview of chiral separation principles and their application in enantioselective nano/micro high performance liquid chromatography (n/μ‐HPLC) using chiral monolith. In particular, developments in silica and polymer chiral monolithic stationary phases are presented. The preparation and applications of chiral monoliths, the basic chiral separation principles and the mechanisms are discussed. Chirality 25:314–323, 2013. © 2013 Wiley Periodicals, Inc.     

核糖代谢失衡与2型糖尿病

Diabetes mellitus(DM)is considered as a group of metabolic diseases characterized by hyperglycemia(high concentration of blood glucose)resulting from defects in insulin secretion,insulin action,or both.Many years ago,Marks[1]emphasized that pentose phosphate pathway is one of important pathways for     

Structural Insight into DFMO Resistant Ornithine Decarboxylase from Entamoeba histolytica: An Inkling to Adaptive Evolution

Background

Polyamine biosynthetic pathway is a validated therapeutic target for large number of infectious diseases including cancer, giardiasis and African sleeping sickness, etc. α-Difluoromethylornithine (DFMO), a potent drug used for the treatment of African sleeping sickness is an irreversible inhibitor of ornithine decarboxylase (ODC), the first rate limiting enzyme of polyamine biosynthesis. The enzyme ODC of E. histolytica (EhODC) has been reported to exhibit resistance towards DFMO.

Methodology/Principal Finding

The basis for insensitivity towards DFMO was investigated by structural analysis of EhODC and conformational modifications at the active site. Here, we report cloning, purification and crystal structure determination of C-terminal truncated Entamoeba histolytica ornithine decarboxylase (EhODCΔ15). Structure was determined by molecular replacement method and refined to 2.8 Å resolution. The orthorhombic crystal exhibits P2₁2₁2₁ symmetry with unit cell parameters a = 76.66, b = 119.28, c = 179.28 Å. Functional as well as evolutionary relations of EhODC with other ODC homologs were predicted on the basis of sequence analysis, phylogeny and structure.

Conclusions/Significance

We determined the tetrameric crystal structure of EhODCΔ15, which exists as a dimer in solution. Insensitivity towards DFMO is due to substitution of key substrate binding residues in active site pocket. Additionally, a few more substitutions similar to antizyme inhibitor (AZI), a non-functional homologue of ODCs, were identified in the active site. Here, we establish the fact that EhODC sequence has conserved PLP binding residues; in contrast few substrate binding residues are mutated similar to AZI. Further sequence analysis and structural studies revealed that EhODC may represent as an evolutionary bridge between active decarboxylase and inactive AZI.     

Systematic Review: Insight into Antimalarial Peptide

Antimalarial peptides varying in size, sequence, charge, conformation and structure, hydrophobicity and amphipathicity reflect their heterogeneity in antimalarial activity. Due to global concern of antimalarial drug resistance, these peptides are seldom in attention for therapeutic values as this microbial and synthetic peptide are likely known for delaying the drug resistance phenomenon. Despite of this, among most of the peptides that have shown activity in cultured parasitized erythrocytes were failing to show its efficacy on in vivo models and few of them that are efficacious are not clinically significant on the host. A systematic literature search was carried out to obtain all related studies in PubMed, EMBASE and GOOGLE SCHOLAR from year 1989 to till date 2015 and we found only 63 studies that focus on antimalarial activity of different peptides originated from different sources under in vitro and in vivo conditions. Antimalarial peptides that are mostly included in this review is the naturally occurring along with their derivatives obtained from different sources ranging from lower prokaryotes to higher eukaryotes. Most of the antimalarial peptides had undergone only in vitro testing on Plasmodium falciparum strains having very less potency, but higher selectivity in comparison to standard drugs. The study included in this article will give future direction for development of more antimalarial peptide with desired efficacy and safety.