Antioxidant and Antidiabetic Properties of Extracts from Three Underutilized Food Plants of North East India

Three underutilized leafy vegetables Sarcochlamys pulcherrima (Roxb.) Gaudich (SP), Ipomoea aquatica Forssk. (IA) and Zanthoxylum rhetsa (Roxb.) DC (ZR) were extracted with different solvents viz. 95 % ethyl alcohol, methanol and hot water. The extracts were evaluated for their antioxidant potential via DPPH, ABTS and FRAP assay along with electroanalytical studies using cyclic voltammetry. The antidiabetic potential was determined by recording their α-amylase and α-glucosidase inhibitory assay. The total phenolic content (TPC), total flavonoid content (TFC) and the liquid chromatography-mass spectrometry (LC/MS) based phytochemical profiles of the extracts were also determined. All three extracts of SP exhibited significant antioxidant capacity. The antidiabetic potential of the IA and ZR extracts was found to be higher than or at par with that of standard acarbose. LC/MS studies reveal the presence of hitherto reported antioxidant and antidiabetic compounds like gamma-aminobutyric acid, cinnamic acid, caffeic acid, α-viniferin, piperlonguminine, niacin, kaempferol, etc., in the extracts.     

Bimodal oxygen uptake in juveniles and adults amphibious fish,Channa (= Ophiocephalus) marulius

Oxygen uptake of Channa marulius was studied under water with and without access to air. There was a significant increase in the oxygen uptake through the gills when access to air was prevented. However, this value (0.863 ± 0.058 mlO₂/indiv./h) was quite low in comparison to the total bimodal oxygen uptake (2.04 ± 0.14 mlO₂/indiv./h) in juveniles. In adult fish the oxygen uptake per unit time increased appreciably (4.673 ± 0.404 mlO₂/indiv./h). In juveniles as well as in adults the air breathing dominated over aquatic breathing. This fish showed a definite circadian rhythm in the bimodal oxygen uptake during different hours of the day.This work was performed in the Ichthyology Laboratory, P. G. Dept. of Zoology, Bhagalpur University, and was supported by a research grant from Bhagalpur University     

Targeted tandem affinity purification of PSD‐95 recovers core postsynaptic complexes and schizophrenia susceptibility proteins

The molecular complexity of mammalian proteomes demands new methods for mapping the organization of multiprotein complexes. Here, we combine mouse genetics and proteomics to characterize synapse protein complexes and interaction networks. New tandem affinity purification (TAP) tags were fused to the carboxyl terminus of PSD‐95 using gene targeting in mice. Homozygous mice showed no detectable abnormalities in PSD‐95 expression, subcellular localization or synaptic electrophysiological function. Analysis of multiprotein complexes purified under native conditions by mass spectrometry defined known and new interactors: 118 proteins comprising crucial functional components of synapses, including glutamate receptors, K⁺ channels, scaffolding and signaling proteins, were recovered. Network clustering of protein interactions generated five connected clusters, with two clusters containing all the major ionotropic glutamate receptors and one cluster with voltage‐dependent K⁺ channels. Annotation of clusters with human disease associations revealed that multiple disorders map to the network, with a significant correlation of schizophrenia within the glutamate receptor clusters. This targeted TAP tagging strategy is generally applicable to mammalian proteomics and systems biology approaches to disease.     

Current understanding of synergistic interplay of chitosan nanoparticles and anticancer drugs: merits and challenges

Recent advances have been made in cancer chemotherapy through the development of conjugates for anticancer drugs. Many drugs have problems of poor stability, water insolubility, low selectivity, high toxicity, and side effects. Most of the chitosan nanoparticles showed to be good drug carriers because of their biocompatibility, biodegradability, and it can be readily modified. The anticancer drug with chitosan nanoparticles displays efficient anticancer effects with a decrease in the adverse effects of the original drug due to the predominant distribution into the tumor site and a gradual release of free drug from the conjugate which enhances drug solubility, stability, and efficiency. In this review, we discuss wider applications of numerous modified chitosan nanoparticles against different tumors and also focusing on the administration of anticancer drugs through various routes. We propose the interaction between nanosized drug carrier and tumor tissue to understand the synergistic interplay. Finally, we elaborate merits of drug delivery system at the tumor site, with emphasizing future challenges in cancer chemotherapy.     

Surfactant aided biodegradation of pyrene using immobilized cells of Mycobacterium frederiksbergense

Low aqueous phase solubility is the major limiting factor in successful biodegradation of pyrene and other polycyclic aromatic hydrocarbons (PAH), which can, however, be overcome by using a suitable surfactant. Biodegradation of pyrene by immobilized cells of Mycobacterium frederiksbergense in presence of non-ionic surfactant Tween 80 was evaluated. For cell immobilization, beads were prepared using calcium alginate as the immobilizing material based on immobilized cell viability and mechanical stability of the beads. Complete degradation of pyrene was achieved employing the immobilized cells in batch shake flask experiments for all four different initial concentrations of the PAH at 100 mg l⁻¹, 200 mg l⁻¹, 400 mg l⁻¹ and 1000 mg l⁻¹. The experimental results of biodegradation of pyrene at very high initial concentration of 1000 mg l⁻¹ using the cell immobilized beads was further investigated in a 3 l fermentor operated at controlled conditions of 150 rpm, 28 °C, pH 7 and 1.5 l min⁻¹ aeration. The results confirmed complete degradation of the PAH with a very higher degradation rate of 250 mg l⁻¹ d⁻¹, which is so far the highest value reported for pyrene biodegradation.     

S100 and annexin proteins identify cell membrane damage as the Achilles heel of metastatic cancer cells

Mechanical activity of cells and the stress imposed on them by extracellular environment is a constant source of injury to the plasma membrane (PM). In invasive tumor cells, increased motility together with the harsh environment of the tumor stroma further increases the risk of PM injury. The impact of these stresses on tumor cell plasma membrane and mechanism by which tumor cells repair the PM damage are poorly understood. Ca²⁺ entry through the injured PM initiates repair of the PM. Depending on the cell type, different organelles and proteins respond to this Ca²⁺ entry and facilitate repair of the damaged plasma membrane. We recently identified that proteins expressed in various metastatic cancers including Ca²⁺-binding EF hand protein S100A11 and its binding partner annexin A2 are used by tumor cells for plasma membrane repair (PMR). Here we will discuss the involvement of S100, annexin proteins and their regulation of actin cytoskeleton, leading to PMR. Additionally, we will show that another S100 member – S100A4 accumulates at the injured PM. These findings reveal a new role for the S100 and annexin protein up regulation in metastatic cancers and identify these proteins and PMR as targets for treating metastatic cancers.     

Immunization with recombinant adenovirus synthesizing the secretory form of Japanese encephalitis virus envelope protein protects adenovirus-exposed mice against lethal encephalitis

Replication-defective recombinant adenoviruses (RAds) were constructed that synthesized the pre-membrane and envelope (E) proteins of Japanese encephalitis virus (JEV). Recombinant virus RAdEa synthesized Ea, the membrane-anchored E protein, and RAdEs synthesized Es, the secretory E protein. Compared with RAdEs, RAdEa replicated poorly in HEK 293A cells and synthesized lower amounts of E protein. Oral immunization of mice with RAds generated low titers of anti-JEV antibodies that had little JEV neutralizing activity. Intra-muscular (IM) immunization of mice with either RAd generated high titers of anti-JEV antibodies. Interestingly, RAdEa induced only low titers of JEV neutralizing antibodies. Titers were significantly higher in case of RAdEs immunization. Splenocytes from mice immunized IM with RAds secreted large amounts of interferon-γ and moderate amounts of interleukin-5 in the presence of JEV and showed cytotoxic activity against JEV-infected cells. Naïve mice immunized IM with RAdEs showed complete protection against a lethal dose of JEV given intra-cerebrally. In order to study the effect of the pre-existing adenovirus 5 (Ad5) immunity on the outcome of the RAdEs immunization, mice were exposed to Ad5 through IM or intra-nasal (IN) routes before immunization with RAdEs. Mice exposed to Ad5 through the IN route, when immunized with RAdEs given IM, or those exposed to Ad5 through the IM route, when immunized with RAdEs given IN, were completely protected against lethal JEV challenge.     

Mutation of a dibasic amino acid motif within the C terminus of the P2X7 nucleotide receptor results in trafficking defects and impaired function

Activation of the P2X(7) receptor by extracellular nucleotides modulates multiple immune functions, including inflammatory mediator production, membrane fusion events, and apoptosis. Previous studies have revealed that the C terminus of this multimeric cation channel possesses a lipid-interaction motif that has been proposed to regulate receptor function. This domain is homologous to the LPS binding region of the LPS binding protein, and we demonstrated that two basic residues (Arg(578), Lys(579)) within this motif are essential for LPS binding to P2X(7) in vitro. Because P2X(7) can influence LPS action, and because lipid interaction motifs modulate the trafficking of other ion channel-linked receptors, we hypothesized that this motif of P2X(7) is critical for receptor function and trafficking. In these studies we mutated Arg(578) and Lys(579) of P2X(7), and the expression profile, channel activity, and pore formation of the mutant were characterized in transfected human embryonic kidney 293 cells. In contrast with the wild-type receptor, the P2X(7)-R578E/K579E mutant fails to demonstrate surface immunoreactivity despite normal levels of total protein expression. This effect on the mutant receptor is unlikely to result from widespread defects in protein folding, because surface localization, determined using conformation-specific Abs, can be restored by growing the cells at 25 degrees C, conditions that slow receptor recycling. Despite surface expression at reduced temperatures, at 25 degrees C the P2X(7)-R578E/K579E mutant still exhibits greatly reduced sodium, potassium, and calcium channel activity when compared with the wild-type receptor, and cannot induce pore formation. These data suggest that the lipid interaction motif of the P2X(7) C terminus controls receptor trafficking and modulates channel activity.     

Localized Surface Plasmon Resonance and Refractive Index Sensitivity of Metal–Dielectric–Metal Multilayered Nanostructures

The localized surface plasmon resonances of multilayered nanostructures are studied using finite difference time domain simulations and plasmon hybridization method. Concentric metal–dielectric–metal (MDM) structure with metal core and nanoshell separated by a thin dielectric layer exhibits a strong coupling between the core and nanoshell plasmon resonance modes. The coupled resonance mode wavelengths show dependence on the dielectric layer thickness and composition of core and outer layer metal. The aluminum-based MDM structures show lower plasmon wavelength compared with Ag- and Au-based MDM nanostructures. The calculated refractive index sensitivity (RIS) factor is in the order Ag–Air–Ag>Au–Air–Au>Al–Air–Al for monometallic multilayered nanostructures. Bimetallic multilayered nanostructures support strong and tunable plasmon resonance wavelengths as well as high RIS factor of 510 nm/refractive index unit (RIU) and 470 nm/RIU for Al–Air–Au and Ag-Air-Au, respectively. The MDM structures not only exhibit higher index sensitivity but also cover a wide ultraviolet–near-infrared wavelengths, making these structures very promising for index sensing, biomolecule sensing, and surface-enhanced Raman spectroscopy.