Carnitine metabolism during exercise in patients with peripheral vascular disease

The distribution between carnitine and the acyl derivatives of carnitine reflects changes in the metabolic state of a variety of tissues. Patients with peripheral vascular disease (PVD) develop skeletal muscle ischemia with exertion. This impairment in oxidative metabolism during exercise may result in the generation of acylcarnitines. To test this hypothesis, 11 patients with PVD and 7 age-matched control subjects were evaluated with graded treadmill exercise. Subjects with PVD walked to maximal claudication pain at a peak O2 consumption (VO2) of 19.9 +/- 1.3 ml X kg-1 X min-1 (mean +/- SE). Control subjects were taken to a near-maximal work load at a VO2 of 31.3 +/- 1.0 ml X kg-1 X min-1. In patients with PVD, the plasma concentration of total acid-soluble, long-chain acylcarnitine and total carnitine was increased at peak exercise compared with resting values. Four minutes postexercise, the plasma short-chain acylcarnitine concentration was also increased. In control subjects taken to the higher work load, only the long-chain acylcarnitine concentration was increased at peak exercise. In patients with PVD, plasma short-chain acylcarnitine concentration at rest was negatively correlated with subsequent maximal walking time (r = -0.51, P less than 0.05). In conclusion, acylcarnitines increased in patients with PVD who walked to maximal claudication pain, whereas control subjects did not show equivalent changes even when taken to a higher work load. The relationship between short-chain acylcarnitine concentration at rest and subsequent exercise performance suggests that repeated episodes of ischemia may cause chronic accumulation of short-chain acylcarnitine in plasma in proportion to the severity of disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Apocynin ameliorates NADPH oxidase 4 (NOX4) induced oxidative damage in the hypoxic human retinal Müller cells and diabetic rat retina

Molecular and Cellular Biochemistry - NADPH oxidase (NOX) is a main producers of reactive oxygen species (ROS) that may contribute to the early pathogenesis of diabetic retinopathy (DR). ROS has...     

Accurate prediction of kinase-substrate networks using knowledge graphs

Phosphorylation of specific substrates by protein kinases is a key control mechanism for vital cell-fate decisions and other cellular processes. However, discovering specific kinase-substrate relationships is time-consuming and often rather serendipitous. Computational predictions alleviate these challenges, but the current approaches suffer from limitations like restricted kinome coverage and inaccuracy. They also typically utilise only local features without reflecting broader interaction context. To address these limitations, we have developed an alternative predictive model. It uses statistical relational learning on top of phosphorylation networks interpreted as knowledge graphs, a simple yet robust model for representing networked knowledge. Compared to a representative selection of six existing systems, our model has the highest kinome coverage and produces biologically valid high-confidence predictions not possible with the other tools. Specifically, we have experimentally validated predictions of previously unknown phosphorylations by the LATS1, AKT1, PKA and MST2 kinases in human. Thus, our tool is useful for focusing phosphoproteomic experiments, and facilitates the discovery of new phosphorylation reactions. Our model can be accessed publicly via an easy-to-use web interface (LinkPhinder).     

Response of tomato (Lycopersicon esculentum Mill.) growth to different phosphorous levels and sowing dates

A field trail was carried out at the University of Agriculture Peshawar during spring, 2013 in order to evaluate the effect of different levels of phosphorus fertilizer and various planting times on the growth and development of tomato. The main objective of the research work was to investigate the best sowing time for tomato in combination with suitable dose of P fertilizer in order to get maximum yield of tomato in the climatic conditions of Peshawar. RCB Design with split plot arrangements was used in the trail. The main factor (phosphorous levels of 0, 90, 110, 130) was allotted to main plots while sowing dates in sub plots. A total twelve treatment were replicated thrice. Maximum days to flowering (39.583?days) and fruiting (46.167?days) obtained in the late sowing. Minimum days to flowering (39), minimum days to fruiting (38.778?days) were taken by the early sowing. Maximum number of branches (27.778), maximum fruit length (6.0222), maximum fruit with (6.1667), maximum fruit yield (24.653?tons?ha^?1) was produced when the plot fertilize with 130?kg?P?ha^?1. Maximum number of fruit?plant^?1 (29.778) were produced with application of 130?kg?P?ha^?1, minimum number of fruits (23.667?cm), fruit width (3.778?cm), fruit length (4.3667?cm), plant height (56.300?cm) were obtained from the controlled treatment. Among the various treatment studied in experiment, it is concluded that early planting of the tomato in the summer season i.e. in the start of March and the use of higher dose of P (130?kg?P?ha^?1) is very beneficial for the excellent growth, development and yield of tomato crop.     

Isolation and enzyme-inhibition studies of the chemical constituents from Ajuga bracteosa

Bractin A (=(2S,3S,4R,5E)-2-{[(2R)-2-hydroxydodecanoyl]amino}triacont-5-ene-1,3,4-triol; 1) and bractin B (=(2S,3S,4R,5E,8E)-2-{[(2R)-2-hydroxyhexacosanoyl]amino}pentadeca-5,8-diene-3,4,15-triol 1-O-beta-D-glucopyranoside; 2), new sphingolipids, and bractic acid (=(5Z,10Z,15Z)-2-decyl-4,7,8,12,13,17,18-heptahydroxy-20,23-dioxopentacosa-5,10,15-trienoic acid; 3), a long-chain polyhydroxy acid, were isolated from the whole plant Ajuga bracteosa along with four known diterpenoids 4-7. Their structures were deduced by spectral studies including 1D- and 2D-NMR spectroscopy. Compounds 1-3 displayed inhibitory potential against enzyme lipoxygenase, while compounds 4-7 inhibited cholinesterase enzymes in a concentration-dependent manner with IC(50) values in the range 10.0-33.0, 14.0-35.2, and 10.0-19.0 microM for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively. Lineweaver-Burk, and Dixon plots, and their secondary replots indicated that all compounds exhibit non-competitive type of inhibition with K(i) values in the range of 9.5-35.2, 15.2-36.0, and 11.6-20.5 microM, for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively.     

Staurosporine-induced cell death in salmonid cells: the role of apoptotic volume decrease, ion fluxes and MAP kinase signaling

Apoptotic cell death in mammalian models is frequently associated with cell shrinkage. Inhibition of apoptotic volume decrease (AVD) is cytoprotective, suggesting that cell shrinkage is an important early event in apoptosis. In salmonid hepatoma and gill cells staurosporine induced apoptosis, as assessed by activation of effector caspases, nuclear condensation, and a decrease of mitochondrial membrane potential (MMP), and these changes were accompanied by cell shrinkage. The Cl⁻ transport inhibitor DIDS and the K⁺ channel inhibitor quinidine prevented AVD, but only DIDS inhibited apoptosis. Other Cl⁻ flux inhibitors, as well as a pan-caspase inhibitor, did not prevent cell shrinkage, but still prevented caspase activation. Furthermore, regulatory volume decrease (RVD) under hypotonic conditions was not facilitated, but diminished in apoptotic cells. Since all transport inhibitors used blocked RVD, but only DIDS and quinidine inhibited AVD, the ion transporters involved in both processes are apparently not identical. In addition, our data indicate that inhibition of Cl⁻ fluxes rather than blocking cell shrinkage or K⁺ fluxes is important for preventing apoptosis. In line with this, inhibition of MAP kinases reduced RVD and not AVD, but still diminished caspase activation. Finally, we observed that MAP kinases were activated upon staurosporine treatment and that at least activation of ERK was prevented when AVD was inhibited.     

Biophysical basis of the binding of WWOX tumor suppressor to WBP1 and WBP2 adaptors

The WW-containing oxidoreductase (WWOX) tumor suppressor participates in a diverse array of cellular activities by virtue of its ability to recognize WW-binding protein 1 (WBP1) and WW-binding protein 2 (WBP2) signaling adaptors among a wide variety of other ligands. Herein, using a multitude of biophysical techniques, we provide evidence that while the WW1 domain of WWOX binds to PPXY motifs within WBP1 and WBP2 in a physiologically relevant manner, the WW2 domain exhibits no affinity toward any of these PPXY motifs. Importantly, our data suggest that while R25/W44 residues located within the binding pocket of a triple-stranded β-fold of WW1 domain are critical for the recognition of PPXY ligands, they are replaced by the chemically distinct E66/Y85 duo at structurally equivalent positions within the WW2 domain, thereby accounting for its failure to bind PPXY ligands. Predictably, not only does the introduction of E66R/Y85W double substitution within the WW2 domain result in gain of function but the resulting engineered domain, hereinafter referred to as WW2_RW, also appears to be a much stronger binding partner of WBP1 and WBP2 than the wild-type WW1 domain. We also show that while the WW1 domain is structurally disordered and folds upon ligand binding, the WW2 domain not only adopts a fully structured conformation but also aids stabilization and ligand binding to WW1 domain. This salient observation implies that the WW2 domain likely serves as a chaperone to augment the physiological function of WW1 domain within WWOX. Collectively, our study lays the groundwork for understanding the molecular basis of a key protein-protein interaction pertinent to human health and disease.     

Insights from Streptococcus pneumoniae glucose kinase structural model

Streptococcus pneumonia is the common cause of sepsis and meningitis. Emergence of multiple antibiotic resistant strains in the community‐acquired bacterium is catastrophic. Glucose kinase (GLK) is a regulatory enzyme capable of adding phosphate group to glucose in the first step of streptomycin biosynthesis. The activity of glucose kinase was regulated by the Carbon Catabolite Repression (CCR) system. Therefore, it is important to establish the structure‐function relation of GLK in S. pneumoniae. However, a solved structure for S. pneumoniae GLK is not available at the protein data bank (PDB). Therefore, we created a model of GLK from S. pnemoniae using the X‐ray structure of Glk from E. faecalis as template with MODELLER (a comparative modeling program). The model was validated using protein structure checking tools such as PROCHECK, WHAT IF and ProSA for reliability. The active site amino acid Asp114 in the template is retained in S. pneumoniae GLK model (Asp115). Solvent accessible surface area (ASA) analysis of the GLK model showed that known key residues playing important role in active site for ligand binding and metal ion binding are buried and hence not accessible to solvent. The information thus discussed provides insight to the molecular understanding of glucose kinase in S. pneumoniae.