Effect in vitro of propoxur on kinetics of K+ stimulated PNPPase and protection by thiol reagents

Kinetics analysis of K+ stimulated PNPPase was studied in the rat brain synaptosomes in the presence of propoxur. Non-competitive inhibition with respect to activation by PNPP was seen by the decreased maximal velocity (Vmax) without change in Michaelis-Menten Constant (Km). Activation energy values (delta E) were increased suggesting the decreased catalytic potential of the enzyme. It is also observed that dithiothrietol (DTT) (76 microM), cysteine (82 microM) and glutathione (120 microM) neutralized the inhibition of K(+)-PNPPase by propoxur to different extents.     

Metabolic regulatory variations in rats due to acute cold stress & Tinospora Cordifolia intervention: high resolution 1H NMR approach

Acute cold stress may trigger systemic biochemical and physiological changes in the living organisms, which leads to rapid loss of homeostasis. These changes may reverse due to self-regulatory mechanism of the organism or by the intervention of suitable medication in the form of herbs. The present study was undertaken to assess the alterations in metabolites levels arising due to acute cold stress and to monitor the restoration of these changes by suitable herb intervention. Male Sprague-Dawley rats were exposed to acute cold stress of ?10°C for 3?h and urine samples were collected and analyzed by NMR spectroscopy in conjugation with Principal Component Analysis (PCA). The study revealed highly significant biochemical changes in urinary metabolites and also demonstrated the protective effects of Tinospora Cordifolia (Tc) extract on the stressed rats. These changes suggest the involvement of various metabolic pathways such as Tricarboxylic Acid (TCA) cycle, gut microbiota, renal function, catecholamines and muscle metabolism in the metabolic alterations induced by cold stress and the compensation required to restore homeostasis. The present study forms the basis of future studies to establish potential biomarkers for cold stress in humans and lay down the optimum dosage of Tc to be administered for providing immunity to the body as prophylactic and mitigating agent against environmental insult such as cold stress.     

Molecular dynamics simulation of shale gas confined inside slit-like calcite [104] nanopore

The growing demand for energy and lack of conventional natural resources has compelled researchers all around the world to pay great attention to the extraction of shale gas, an unconventional natural gas trapped within shale formations. To enhance the gas recovery process and minimise the environmental hazards requires improved technologies. It has been reported that most of the gases trapped in shale rock formations are adsorbed in complex nano-size heterogeneous pores. However, only an insignificant amount of information is available. It is desired to investigate the microscopic behaviour of these gases under nano-confinement for the advancement of enhanced gas recovery (EGR) technologies. In the proposed work, Molecular Dynamics (MD) simulation techniques are used to study the structural and dynamical behaviour of shale gas, which is roughly an 80–20% molar mixture of methane and ethane respectively, confined inside 2.2?nm, slit-like nanopores. The calcite [104] surface has been chosen, as it is the most stable calcite surface. The density profiles of gases are calculated at various temperatures to understand the structural behaviour. The mean square displacements (MSDs) and self-diffusion coefficients are calculated to understand the dynamical behaviour inside the nanopore.     

Reversal of P-glycoprotein-mediated multidrug resistance by natural N-alkylated indole alkaloid derivatives in KB-ChR-8-5 drug-resistant cancer cells

Multidrug resistance (MDR) remains a significant challenge in cancer chemotherapy due to the overexpression of ATP-binding cassette drug-efflux transporters, namely P-glycoprotein (P-gp)/ATP-binding cassette subfamily B member 1. In this study, derivatives of N-alkylated monoterpene indole alkaloids such as N-(para-bromobenzyl) (NBBT), N-(para-methylbenzyl) (NMBT), and N-(para-methoxyphenethyl) (NMPT) moieties were investigated for the reversal of P-gp-mediated MDR in drug-resistant KB colchicine-resistant 8-5 (KB-ChR-8-5) cells. Among the three indole alkaloid derivatives, the NBBT exhibited the highest P-gp inhibitory activity in a dose-dependent manner. Further, it significantly decreased P-gp overexpression by inactivating the nuclear translocation of the nuclear factor kappa B p-50 subunit. In the cell survival assay, doxorubicin showed 6.3-fold resistance (FR) in KB-ChR-8-5 cells compared with its parental KB-3-1 cells. However, NBBT significantly reduced doxorubicin FR to 1.7, 1.3, and 0.4 and showed strong synergism with doxorubicin for all the concentrations studied in the drug-resistant cells. Furthermore, NBBT and doxorubicin combination decreased the cellular migration and showed increased apoptotic incidence by downregulating Bcl-2, then activating BAX, caspase 3, and p53. The present findings suggest that NBBT could be a lead candidate for the reversal of P-gp- mediated multidrug resistance in cancer cells.     

Hepatic Gene Expression in Morbidly Obese Women: Implications for Disease Susceptibility

The objective of this study was to determine the molecular bases of disordered hepatic function and disease susceptibility in obesity. We compared global gene expression in liver biopsies from morbidly obese (MO) women undergoing gastric bypass (GBP) surgery with that of women undergoing ventral hernia repair who had experienced massive weight loss (MWL) following prior GBP. Metabolic and hormonal profiles were examined in MO vs. MWL groups. Additionally, we analyzed individual profiles of hepatic gene expression in liver biopsy specimens obtained from MO and MWL subjects. All patients underwent preoperative metabolic profiling. RNAs were extracted from wedge biopsies of livers from MO and MWL subjects, and analysis of mRNA expression was carried out using Affymetrix HG‐U133A microarray gene chips. Genes exhibiting greater than twofold differential expression between MO and MWL subjects were organized according to gene ontology and hierarchical clustering, and expression of key genes exhibiting differential regulation was quantified by real‐time–polymerase chain reaction (RT‐PCR). We discovered 154 genes to be differentially expressed in livers of MWL and MO subjects. A total of 28 candidate disease susceptibility genes were identified that encoded proteins regulating lipid and energy homeostasis (PLIN, ENO3, ELOVL2, APOF, LEPR, IGFBP1, DDIT4), signal transduction (MAP2K6, SOCS‐2), postinflammatory tissue repair (HLA‐DQB1, SPP1, P4HA1, LUM), bile acid transport (SULT2A, ABCB11), and metabolism of xenobiotics (GSTT2, CYP1A1). Using gene expression profiling, we have identified novel candidate disease susceptibility genes whose expression is altered in livers of MO subjects. The significance of altered expression of these genes to obesity‐related disease is discussed.     

Juglone promotes shooting and inhibits rooting in leaf explants of in vitro raised tomato (Solanum lycopersicum L. var. Pusa Ruby) seedlings

In Vitro Cellular & Developmental Biology - Plant - Juglone is an inhibitor of choline acetyltransferase, an enzyme that catalyzes the synthesis of acetylcholine. Previous works have shown the...     

Elastic Properties and Heterogeneous Stiffness of the Phi29 Motor Connector Channel

The DNA packaging motor of the bacteriophage ϕ29, comprising head-tail connector, ATPase, and pRNA, transports the viral DNA inside the procapsid against pressure differences of up to ∼60 atm during replication. Several models for the DNA packaging mechanism have been proposed, which attribute different roles to the connector, and require specific mechanical properties of the connector. To characterize these properties at the atomic level, and to understand how the connector withstands this large pressure, we have carried out molecular dynamics simulations of the whole connector both in equilibrium and under mechanical stress. The simulations revealed a quite heterogeneous distribution of stiff and soft regions, resembling that of typical composite materials that are also optimized to resist mechanical stress. In particular, the conserved middle α-helical region is found to be remarkably stiff, similar only to structural proteins forming viral shell, silk, or collagen. In contrast, large parts of the peripheral interface to the ϕ29 procapsid turned out to be rather soft. Force probe and umbrella sampling simulations showed that large connector deformations are remarkably reversible, and served to calculate the free energies required for these deformations. In particular, for an untwisting deformation by 12°, as postulated by the untwist-twist model, more than four times’ larger energy is required than is available from hydrolysis of one ATP molecule. Combined with previous experiments, this result is incompatible with the untwist-twist model. In contrast, our simulations support the recently proposed one-way revolution model and suggest in structural terms how the connector blocks DNA leakage. In particular, conserved loops at the rim of the central channel, which are in direct contact with the DNA, are found to be rather flexible and tightly anchored to the rigid central region. These findings suggest a check-valve mechanism, with the flexible loops obstructing the channel by interacting with the viral DNA.