Isoxazole-based derivatives from Baylis-Hillman chemistry: assessment of preliminary hypolipidemic activity

The synthesis of isoxazole-based derivatives utilizing Baylis-Hillman chemistry and results of their preliminary bioevaluation as hypolipidemic agents in triton model are described.     

Early-Life Intervention of Lactoferrin and Probiotic in Suckling Piglets: Effects on Immunoglobulins,Intestinal Integrity,and Neonatal Mortality

Probiotics and Antimicrobial Proteins - The aim of this study was to determine the effects of early-life bovine lactoferrin and host specific probiotic interventions on growth performance,...     

A particle-based computational model to analyse remodelling of the red blood cell cytoskeleton during malaria infections

Red blood cells can withstand the harsh mechanical conditions in the vasculature only because the bending rigidity of their plasma membrane is complemented by the shear elasticity of the underlying spectrin-actin network. During an infection by the malaria parasite Plasmodium falciparum, the parasite mines host actin from the junctional complexes and establishes a system of adhesive knobs, whose main structural component is the knob-associated histidine rich protein (KAHRP) secreted by the parasite. Here we aim at a mechanistic understanding of this dramatic transformation process. We have developed a particle-based computational model for the cytoskeleton of red blood cells and simulated it with Brownian dynamics to predict the mechanical changes resulting from actin mining and KAHRP-clustering. Our simulations include the three-dimensional conformations of the semi-flexible spectrin chains, the capping of the actin protofilaments and several established binding sites for KAHRP. For the healthy red blood cell, we find that incorporation of actin protofilaments leads to two regimes in the shear response. Actin mining decreases the shear modulus, but knob formation increases it. We show that dynamical changes in KAHRP binding affinities can explain the experimentally observed relocalization of KAHRP from ankyrin to actin complexes and demonstrate good qualitative agreement with experiments by measuring pair cross-correlations both in the computer simulations and in super-resolution imaging experiments.     

Production,characterization and applications of microbial cutinases

Cutinase is an enzyme that catalyses the degradation of insoluble biopolyester cutin, a structural component of plants. This enzyme has some properties of lipase and esterase. Because of its unique nature, it has potential of being an industrially important enzyme. Some of the useful applications of cutinase include hydrolysis of fats and oils, esterification and transesterification reactions. This enzyme is mainly produced by phytopathogenic fungi, but there are several bacteria which are known to produce cutinase. In this article, the production, purification, characterizations, enhancement of activity and stability, immobilization of the enzyme and its applications in various industries have been discussed.     

Baylis-Hillman reaction assisted parallel synthesis of 3,5-disubstituted isoxazoles and their in vivo bioevaluation as antithrombotic agents

The solution-phase parallel synthesis involving reactions of Baylis-Hillman products of 3-substituted-5-isoxazolecarbaldehydes with nucleophiles and their in vivo antithrombotic evaluations are described along with the results of in vitro platelet aggregation inhibition assay of a few compounds. Results of the detailed evaluation of one of the compounds as an inhibitor of platelet aggregation are also presented.     

Light-induced inhibition of papain by a {Mn-NO}6 nitrosyl: identification of papain-SNO adduct by mass spectrometry

Modification of Cys25 at the active site of the cysteine protease papain by S-nitrosylation inhibits its hydrolytic ability. Previous studies have demonstrated that NO donors N-nitrosoanilines inhibit papain activity via formation of S-NO bond formation at the active site while NO donors such as S-nitroso-N-acetyl-penicillamine (SNAP), N-nitrosoaniline derivatives, and S-nitroso-glutathione (GSNO) inhibit the enzyme via S-thiolation by thiyl radicals generated from the S-nitrosothiols. In this study, we report papain inactivation by a photosensitive {Mn-NO}(6) nitrosyl [(PaPy(3))Mn(NO)](ClO(4)) (1) where PaPy(3)(-) is the anion of the designed ligand N,N-bis(2-pyridylmethyl)amine-N-ethyl-2-pyridine-2-carboxamide. This nitrosyl releases NO upon exposure to visible light of low intensity (50W tungsten lamp). With N(alpha)-benzoyl-l-arginine-p-nitroanilide (l-BApNA) as the substrate, the dissociation constant for the breakdown of the enzyme-inactivator complex (K(I)) and the overall inactivation rate constant (k(i)) were calculated to be 2.46mM and 64.8min(-1), respectively. The papainS-NO adduct has been identified using electrospray mass spectrometry (ESI-MS). The results demonstrate that controlled inactivation of papain can be achieved with the {Mn-NO}(6) nitrosyl 1 and light. The reaction is clean and the extent of inactivation is directly proportional to the exposure time.     

Activation of endothelial NADPH oxidase during normoxic lung ischemia is KATP channel dependent

Previous studies have shown endothelial cell membrane depolarization and generation of reactive oxygen species (ROS) in endothelial cells with abrupt reduction in shear stress (ischemia). This study evaluated the role of ATP-sensitive potassium (K(ATP)) channels and NADPH oxidase in the ischemic response by using Kir6.2-/- and gp91(phox)-/- mice. To evaluate ROS generation, we subjected isolated perfused mouse lungs labeled with 2',7'-dichlorodihydrofluorescein (DCF), hydroethidine (HE), or diphenyl-1-pyrenylphosphine (DPPP) to control perfusion followed by global ischemia. In wild-type C57BL/6J mice, imaging of subpleural endothelial cells showed a time-dependent increase in intensity for all three fluorescence probes with ischemia, which was blocked by preperfusion with cromakalim (a K(ATP) channel agonist) or diphenyleneiodonium (DPI, a flavoprotein inhibitor). Endothelial cell fluorescence with bis-oxonol, a membrane potential probe, increased during lung ischemia indicating cell membrane depolarization. The change in membrane potential with ischemia in lungs of gp91(phox)-/- mice was similar to wild type, but ROS generation did not occur. Lungs from Kir6.2-/- showed marked attenuation of the change in both membrane potential and ROS production. Thus membrane depolarization during lung ischemia requires the presence of a K(ATP) channel and is required for activation of NADPH oxidase and endothelial ROS generation.     

Human placental lipid induces melanogenesis through p38 MAPK in B16F10 mouse melanoma

Melanogenesis is one of the characteristic functional activities of melanocyte/melanoma and is regulated via mitogen-activated protein kinase (MAPK) and Akt/protein kinase B (PKB) pathways. Placental total lipid fraction (PTLF), prepared from a hydroalcoholic extract of fresh term human placenta contains sphingolipids and was recently shown to stimulate melanogenesis via up-regulation of the key enzyme tyrosinase in B16F10 mouse melanoma cells. How such lipids mediate their effects on pigmentation and tyrosinase expression is a particularly important aspect of melanogenesis. To study the signaling that leads to tyrosinase expression, we have investigated the roles of the MAPK and Akt/PKB pathways in B16F10 melanoma cells in melanogenesis in response to PTLF. Treatment of cells with PTLF led to the time dependent phosphorylation of p38 MAPK. SB203580, a p38 MAPK inhibitor, completely blocked the PTLF-induced melanogenesis by inhibiting promoter activity and subsequent expression of tyrosinase. Phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002 a blocker of the Akt signaling pathway, or an inhibitor of MEK (MAPK/ERK Kinase), PD98059 when included along with PTLF was found to potentiate PTLF-induced phosphorylation of p38 MAPK together with tyrosinase expression and melanogenesis. The results suggest that the activation of p38 MAPK plays a crucial role in PTLF-induced B16F10 melanogenesis by up-regulating tyrosinase expression.