Modeling and Analysis of Unsteady Axisymmetric Squeezing Fluid Flow through Porous Medium Channel with Slip Boundary

The aim of this article is to model and analyze an unsteady axisymmetric flow of non-conducting, Newtonian fluid squeezed between two circular plates passing through porous medium channel with slip boundary condition. A single fourth order nonlinear ordinary differential equation is obtained using similarity transformation. The resulting boundary value problem is solved using Homotopy Perturbation Method (HPM) and fourth order Explicit Runge Kutta Method (RK4). Convergence of HPM solution is verified by obtaining various order approximate solutions along with absolute residuals. Validity of HPM solution is confirmed by comparing analytical and numerical solutions. Furthermore, the effects of various dimensionless parameters on the longitudinal and normal velocity profiles are studied graphically.     

Phylogenetic Analysis of Selected Menthol-Producing Species Belonging to the Lamiaceae Family

Menthol is an organic compound with diverse medicinal and commercial applications, and is made either synthetically or through extraction from mint oils. The aim of the present study was to investigate menthol levels in selected menthol-producing species belonging to the Lamiaceae family, and to determine phylogenetic relationships of menthol dehydrogenase gene sequence among these species. Three genus of Lamiaceae, namely Mentha, Salvia, and Micromeria, were selected for phytochemical and phylogenetic analyses. After identification of each species based on menthol dehydrogenase gene in NCBI, BLAST software was used for the sequence alignment. MEGA4 software was used to draw phylogenetic tree for various species. Phytochemical analysis revealed that the highest and lowest amounts of both essential oil and menthol belonged to Mentha spicata and Micromeria hyssopifolia, respectively. The species Mentha spicata and Mentha piperita, which were assigned to one cluster in the dendrogram, contained the highest amounts of essential oil and menthol while Micromeria species, which was in the distinct cluster and placed in the farther evolutionary distance, contained the lowest amount of essential oil and menthol. Phylogenetic and phytochemistry analyses showed that essential oil and menthol contents of menthol-producing species are associated with menthol dehydrogenase gene sequence.     

Insights into laccase producing organisms,fermentation states,purification strategies,and biotechnological applications

Laccases are phenol oxidases belonging to the superfamily of multicopper oxidases and are found in bacteria, fungi, lichens, higher plants, and insects. Over the past few decades, laccases and laccase mediator systems (LMS) have found uses in a wide range of technological applications such as textile dye decolorization, industrial wastewater detoxification, pulp bleaching, chemical synthesis, and development of miniaturized biosensors. This has encouraged numerous studies to find and purify laccases with exploitable characteristics. The main aim of the present review is to summarize the rich literature data gained in recent years from the studies on laccases, focusing on the organisms that produce them, the methods used for screening, laccase activity assays, purification strategies, and the application of laccases as eco‐friendly biocatalysts. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1443–1463, 2015     

Comparative Analysis of Peripheral Alkaline Phytase Protein Structures Expressed in E. coli

Background:

Degradation of phytic acid to inorganic phosphate in domestic animals’ diets requires thermostable phytase. Although Basillus subtilis phytase shows a potential to be degraded phytate complex in high temperature, the enzyme activities and yields need to be increased to make them possible for industrial application.

Methods:

The phytase gene from Bacillus subtilis DR8886 was isolated from Dig Rostam hot mineral spring in Iran and cloned into pET21(+) and pET32(+). Expression was induced with 1.5 mM IPTG and the proteins were purified.

Results:

The recombinant protein affected by thioredoxin (Trx) from pET32a-PhyC was estimated to constitute about 31% of the total soluble protein in the cells; its concentration was 3.5 µg/ml, and its maximal phytase activity was 15.9 U/ml, whereas the recombinant phytase from pET21a-PhyC was estimated to comprise about 19% of the total soluble protein; its concentration was 2.2 µg/ml, and its maximal phytase activity was 69 U/ml. The molecular masses of recombinant phytase with and without Trx were about 60 kDa and 42 kDa, respectively. Zymography confirmed that the recombinant enzymes were active. Although the concentration of the alkaline phytase expressed by pET32a was approximately 59% greater than that expressed by pET21, its phytase activity was approximately 77% less.

Conclusion:

This study showed that the peripheral gene (Trx) encoded by the pET32a (+) vector are the principal reason for the decrease in recombinant phytase enzyme activity.Key Words: Bacillus subtilis DR8806, PhyC Gene, Thioredoxin     

Detection of Hepatitis E Virus Antibodies in Dogs in the United Kingdom

Hepatitis E virus (HEV) genotypes 3 and 4 are zoonotic pathogens, with pigs predominantly implicated in disease transmission. The rapid rise in human cases in developed countries over the past decade indicates a change in epidemiology of HEV, and it has been suggested that additional animal species may be involved in transmission of infection. Multiple studies have identified contact with dogs as a risk factor for HEV infection in industrialised nations, and a low seroprevalence to HEV has previously been reported in dogs in low-income countries. In this study we aimed to evaluate the possibility that dogs are susceptible to HEV, and determine the frequency with which this occurs. Serum samples from UK dogs with and without hepatitis were screened for HEV-specific antibodies, and canine liver and stool samples were analysed by qPCR for the presence of HEV RNA. We describe evidence to show HEV infection occurs at low levels in dogs in the UK, but the strain of origin is undetermined. The low seroprevalence level of HEV in dogs implies the risk of zoonotic disease transmission is likely to be limited, but further investigations will be required to determine if HEV-infected dogs can transmit HEV to man.     

Mechanistic insights into mode of action of potent natural antagonists of BACE-1 for checking Alzheimer’s plaque pathology

Alzheimer’s is a neurodegenerative disorder resulting in memory loss and decline in cognitive abilities. Accumulation of extracellular beta amyloidal plaques is one of the major pathology associated with this disease. β-Secretase or BACE-1 performs the initial and rate limiting step of amyloidic pathway in which 37–43 amino acid long peptides are generated which aggregate to form plaques. Inhibition of this enzyme offers a viable prospect to check the growth of these plaques. Numerous efforts have been made in recent years for the generation of BACE-1 inhibitors but many of them failed during the preclinical or clinical trials due to drug related or drug induced toxicity. In the present work, we have used computational methods to screen a large dataset of natural compounds to search for small molecules having BACE-1 inhibitory activity with low toxicity to normal cells. Molecular dynamics simulations were performed to analyze molecular interactions between the screened compounds and the active residues of the enzyme. Herein, we report two natural compounds of inhibitory nature active against β-secretase enzyme of amyloidic pathway and are potent lead molecules against Alzheimer’s disease.     

Green synthesis of gold nanoparticles by the marine microalga Tetraselmis suecica

The application of green-synthesis principles is one of the most impressive research fields for the production of nanoparticles. Different kinds of biological systems have been used for this purpose. In the present study, AuNPs (gold nanoparticles) were prepared within a short time period using a fresh cell extract of the marine microalga Tetraselmis suecica as a reducing agent of HAuCl4 (chloroauric acid) solution. The UV-visible spectrum of the aqueous medium containing AuNPs indicated a peak at 530 nm, corresponding to the surface plasmon absorbance of AuNPs. The X-ray diffraction pattern also showed a Bragg reflection related to AuNPs. Fourier-transform infrared spectroscopy was performed for analysis of surface functional groups of AuNPs. Transmission electron microscopy and particle-size-distribution patterns determined by the laser-light-scattering method confirmed the formation of well-dispersed AuNPs. The most frequent size of particles was 79 nm.     

Bisleuconothine A,an eburnane–aspidosperma bisindole alkaloid from Leuconotis griffithii

A new bisindole alkaloid, bisleuconothine A (1) consisting of an eburnane–aspidosperma type skeleton, was isolated from the bark of Leuconotis griffithii. The structure including absolute stereochemistry was elucidated on the basis of 2D NMR data and X-ray analysis. Bisleuconothine A (1) showed cell growth inhibitory activity against various human cancer cell lines.