Characterization of exopolysaccharide produced by Lactobacillus kefiranofaciens ZW3 isolated from Tibet kefir – Part II

ZW3 is a newly discovered exopolysaccharide (EPS) produced by Lactobacillus kefiranofaciens ZW3, isolated from Tibet kefir. Some of its properties have been characterized in our previous paper. Present research demonstrates some other important aspects of this EPS. The molecular weight obtained by gel permeation HPLC was 5.5 × 10⁴ Da. Solubility, water holding and oil binding capacity of ZW3 EPS were 14.2%, 496.0%, and 884.74% respectively. Scanning electron microscopy (SEM) of ZW3 EPS demonstrated a smooth surface with compact structures. A topographical examination of EPS by atomic force microscopy (AFM) revealed that ZW3 EPS is composed of almost uniform net of molecules. Rheological study indicated that common salt did not affect the viscous behavior of ZW3 EPS and acidic pH may enhance its viscosity. Exopolymer showed a melting point of 93.38 °C. A degradation temperature (Td) of 299.62 °C was observed from the TGA curve for the polysaccharide ZW3.     

G-Protein-Coupled Lysophosphatidic Acid Receptors and Their Regulation of AKT Signaling

A hallmark of G-protein-coupled receptors (GPCRs) is their ability to recognize and respond to chemically diverse ligands. Lysophospholipids constitute a relatively recent addition to these ligands and carry out their biological functions by activating G-proteins coupled to a large family of cell-surface receptors. This review aims to highlight salient features of cell signaling by one class of these receptors, known as lysophosphatidic acid (LPA) receptors, in the context of phosphatidylinositol 3-kinase (PI3K)–AKT pathway activation. LPA moieties efficiently activate AKT phosphorylation and activation in a multitude of cell types. The interplay between LPA, its receptors, the associated Gαi/o subunits, PI3K and AKT contributes to the regulation of cell survival, migration, proliferation and confers chemotherapy-resistance in certain cancers. However, detailed information on the regulation of PI3K–AKT signals induced by LPA receptors is missing from the literature. Here, some urgent issues for investigation are highlighted.     

Oil quality characteristics of irradiated sunflower and maize seed

The characteristics of oils extracted from gamma‐irradiated sunflower (Halianthus annuus) and maize (Zea mays) seeds at absorbed doses of 2, 4, 6, 8, and 10 kGy were investigated. Gamma irradiation did not affect the lipid, protein, fiber, and ash contents of neither sunflower nor maize seeds significantly (p>0.05). No significant changes were observed for the values of refractive index and density between the control and irradiated sunflower and maize oils. Peroxide value, acid value, para‐anisidine value, and conjugated dienes and trienes contents increased, while iodine values decreased in the irradiated oils as compared to those of control oils (p<0.05). A small decrease in the contents of α‐, γ‐, and δ‐tocopherols of both sunflower and maize oils was noted by radiation treatment up to 6 kGy, however, the decline was more pronounced at higher dosages. The effects of irradiation on the fatty acid composition of sunflower oil showed a significant (p<0.05) change in the amounts of stearic, oleic, and linoleic acids, while the concentration of palmitic acid was unaffected even at 10 kGy. Similar trends in the fatty acid profile were found for both the sunflower and maize oil.     

Tailoring of structural and magnetic properties by substitution of copper in cobalt chromium ferrites

The simple and cost-effective powder metallurgy method has been employed to prepare a series of copper substituted cobalt chromium ferrites Cu_xCo_1-xCr_0.5Fe₂O₄ (x?=?0, 0.2, 0.4, 0.6, 0.8, 1.0). The calcination of the samples has been carried out at 1100?°C for 24?h. X-Ray Diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR) measurement proves the formation of cubic spinel ferrites. Vibrating Sample Magnetometer (VSM)) analysis revealed that the substitution of copper in the Co-Cr ferrites leads to reduce the magnetic moment that in turns decrease the saturation magnetization and coercivity. The Ultra violet visible spectroscopy (UV–VIS) showed that the band gap energy increases with copper substitution which is due to reduction in crystallite size. The results indicate that the replacement of copper with the cobalt-chromium ferries strongly influences the crystal structure, microstructure, magnetic parameters and band gap energy.     

Lactobacillus acidophilus: Characterization of the Species and Application in Food Production

L. acidophilus is a homofermentative, microaerophilic, short chain gram positive microorganism with rod morphology having its bacteriocins belonging to class II a. Several bacteriocins of L. acidophilus have been isolated and characterized. These are structurally similar, but their molecular weight varies as well as their spectrum of antimicrobial activity. They exhibit important technical properties, i.e., thermostability and retaining of activity at a wide pH range along with strong inhibitory actions against food spoilage and pathogenic bacteria make them an important class of biopreservatives. L. acidophilus can be added as an adjunct in many food fermentation processes contributing to unique taste, flavor, and texture. It also preserves the products by producing lactic acid and bacteriocins. A lot of new information regarding the bacteriocins of L. acidophilus has emerged during the last few years. In this review, an attempt has been made to summarize and discuss all the available information regarding the sources of bacteriocins production, their characteristics, and their antimicrobial action along with their application.     

Morphological and structural analysis of nano-structured gold thin film on silicon by pulsed laser deposition technique

Structural and morphological investigations on optimized nano-structured gold thin film (under vacuum ∼10⁻³ Torr) are reported. The Au optimized thin film was deposited on 4 N polished and analytic grade p-type single crystal (111) Silicon wafer by pulsed laser deposition (PLD) technique, under a vacuum of about 10⁻³ Torr at room temperature. The space resolved dynamics of the plume is studied by analyzing CCD images of plume. Average size of deposited nanoparticles is along the preferred (111) orientation is ∼ 20 nm using PLD technique. The deposited film is non-uniform with particle size within the range of 6.19 nm-19.62 nm. There is decrease in the value of dislocation line density. XRD and SEM investigations support each other.     

Effect of irradiation by 140 Mev Ag ions on the optical and electrical properties of polypropylene/TiO2 composite

Changes in the optical, structural, dielectric properties and surface morphology of a polypropylene/TiO₂ composite due to swift heavy ion irradiation were studied by means of UV–visible spectroscopy, X-ray diffraction, impedance gain phase analyzer and atomic force microscopy. Samples were irradiated with 140 MeV Ag¹¹⁺ ions at fluences of 1 × 10¹¹ and 5 × 10¹² ions/cm². UV–visible absorption analysis reveals a decrease in optical direct band gap from 2.62 to 2.42 eV after a fluence of 5 × 10¹² ions/cm². X-ray diffractograms show an increase in crystallinity of the composite due to irradiation. The dielectric constants obey the Universal law given by ε α f ⁿ⁻¹, where n varies from 0.38 to 0.91. The dielectric constant and loss are observed to change significantly due to irradiation. Cole–cole diagrams have shown the frequency dependence of the complex impedance at different fluences. The average surface roughness of the composite decreases upon irradiation.     

Comparative pollen and foliar micromorphological studies using light microscopy and scanning electron microscopy of some selected species of Lamiaceae from Alpine Zone of Deosai Plateau,Western Himalayas

The study was conducted to highlight a detailed account of morphology of pollen chosen species of Lamiaceae through scanning electron microscopy, and the anatomical characteristics of leaf epidermis of seven species using simple light microscopy. In results, Anisomeles indica and Otostegia aucheri belong to subfamily Lamioideae because it has tricolpate pollen while the rest eight species belong to subfamily Nepetoideae (hexacolpate pollen). The exine sculpturing of pollen of studied species was found to be reticulate. In the family Lamiaceae, four kinds of stomata were found anomocytic, anisocytic, diacytic, and actinocytic, respectively. The cell wall patterns of epidermal cells were irregular or polygonal with straight or undulate walls. It was noted that the variety of the epidermal trichomes seems of taxonomically important for the identification of species of Lamiaceae. Both nonglandular and glandular trichomes were analyzed. The nonglandular trichomes were characterized with long, thin, and pointed apical unicellular cells. The nonglandular trichomes were A‐shaped in Thymus linearis. In Perovskia abrotanoides, stellate glandular trichomes were observed whereas in A. indica and Mentha royleana both glandular and nonglandular trichomes were found. In A. indica, the nonglandular trichomes were sessile and peltate in M. royleana. For the first time in this study, pollen and foliar micromorphological features of selected species of this area are carried out. These taxonomic characters were found to be important in discrimination of species from each other. In future, the detailed study with comprehensive morphology coupled with other important characters is required for delimitation of taxa at various levels.