Amelioration of pneumonia with Streptococcus pneumoniae infection by inoculation with a vaccine against highly pathogenic avian influenza virus in a non-human primate mixed infection model

Background  Highly pathogenic avian influenza virus (HPAIV) infection has a high mortality rate in humans. Secondary bacterial pneumonia with HPAIV infection has not been reported in human patients, whereas seasonal influenza viruses sometimes enhance bacterial pneumonia, resulting in substantial morbidity and mortality. Therefore, if HPAIV infection were accompanied by bacterial infection, an increase in mortality would be expected. We examined whether a vaccine against HPAIV prevents severe morbidity caused by mixed infection with HPAIV and bacteria.
Methods  H7N7 subtype of HPAIV and Streptococcus pneumoniae were inoculated into cynomolgus macaques with or without vaccination of inactivated whole virus particles .
Results  Vaccination against H7N7 HPAIV decreased morbidity caused by HPAIV and pneumonia caused by S. pneumoniae . Bacterial replication in lungs was decreased by vaccination against HPAIV, although the reduction in bacterial colonies was not significant.
Conclusions  Vaccination against HPAIV reduces pneumonia caused by bacterial superinfection and may improve prognosis of HPAIV-infected patients.     

Musculoskeletal-see-through mirror: Computational modeling and algorithm for whole-body muscle activity visualization in real time

In this paper, we present a system that estimates and visualizes muscle tensions in real time using optical motion capture and electromyography (EMG). The system overlays rendered musculoskeletal human model on top of a live video image of the subject. The subject therefore has an impression that he/she sees the muscles with tension information through the cloth and skin. The main technical challenge lies in real-time estimation of muscle tension. Since existing algorithms using mathematical optimization to distribute joint torques to muscle tensions are too slow for our purpose, we develop a new algorithm that computes a reasonable approximation of muscle tensions based on the internal connections between muscles known as neuronal binding. The algorithm can estimate the tensions of 274 muscles in only 16 ms, and the whole visualization system runs at about 15 fps. The developed system is applied to assisting sport training, and the user case studies show its usefulness. Possible applications include interfaces for assisting rehabilitation.     

Impact of insulin resistance on enhanced monocyte adhesion to endothelial cells and atherosclerogenesis independent of LDL cholesterol level

Epidemiological studies suggest that insulin resistance is an independent risk factor for cardiovascular disease. However, there is little information on the role of insulin resistance in atherosclerogenesis independent of LDL cholesterol level. The aim of this study was to investigate the impact of systemic insulin resistance on monocyte adhesion to endothelial cells and atherosclerotic lesions independent of LDL cholesterol level. KKAy mice are obese mice with spontaneous diabetes and insulin resistance, and normal levels of LDL cholesterol. In parallel with systemic insulin resistance, decreased insulin signal, and the increased expression of monocyte chemoattractant protein-1 (MCP-1) were noted in macrophages isolated from KKAy mice. These mice showed enhanced monocyte adhesion to the endothelial cells of the thoracic artery. Furthermore, these mice showed expanded atherosclerotic lesions when fed high cholesterol diet. Our data indicate that insulin resistance promotes the atherosclerogenesis independent of LDL cholesterol level. Decreased insulin signaling in macrophages associated with systemic insulin resistance could be involved, at least in part, in this pathological process.     

Purification and kinetic characterization of recombinant alternative oxidase from Trypanosoma brucei brucei

The trypanosome alternative oxidase (TAO) functions in the African trypanosomes as a cytochrome-independent terminal oxidase, which is essential for their survival in the mammalian host and as it does not exist in the mammalian host is considered to be a promising drug target for the treatment of trypanosomiasis. In the present study, recombinant TAO (rTAO) overexpressed in a haem-deficient Escherichia coli strain has been solubilized from E. coli membranes and purified to homogeneity in a stable and highly active form. Analysis of bound iron detected by inductively coupled plasma-mass spectrometer (ICP-MS) reveals a stoichiometry of two bound iron atoms per monomer of rTAO. Confirmation that the rTAO was indeed a diiron protein was obtained by EPR analysis which revealed a signal, in the reduced forms of rTAO, with a g-value of 15. The kinetics of ubiquiol-1 oxidation by purified rTAO showed typical Michaelis-Menten kinetics (K_m of 338 μM and V_max of 601 μmol/min/mg), whereas ubiquinol-2 oxidation showed unusual substrate inhibition. The specific inhibitor, ascofuranone, inhibited the enzyme in a mixed-type inhibition manner with respect to ubiquinol-1.     

Comparing biological networks via graph compression

Background

Comparison of various kinds of biological data is one of the main problems in bioinformatics and systems biology. Data compression methods have been applied to comparison of large sequence data and protein structure data. Since it is still difficult to compare global structures of large biological networks, it is reasonable to try to apply data compression methods to comparison of biological networks. In existing compression methods, the uniqueness of compression results is not guaranteed because there is some ambiguity in selection of overlapping edges.

Results

This paper proposes novel efficient methods, CompressEdge and CompressVertices, for comparing large biological networks. In the proposed methods, an original network structure is compressed by iteratively contracting identical edges and sets of connected edges. Then, the similarity of two networks is measured by a compression ratio of the concatenated networks. The proposed methods are applied to comparison of metabolic networks of several organisms, H. sapiens, M. musculus, A. thaliana, D. melanogaster, C. elegans, E. coli, S. cerevisiae, and B. subtilis, and are compared with an existing method. These results suggest that our methods can efficiently measure the similarities between metabolic networks.

Conclusions

Our proposed algorithms, which compress node-labeled networks, are useful for measuring the similarity of large biological networks.

     

Magnesium deprivation inhibits a MEK–ERK cascade and cell proliferation in renal epithelial Madin-Darby canine kidney cells

AimsLoss of magnesium (Mg²⁺) inhibits cell proliferation and augments nephrotoxicant-induced renal injury, but the role of Mg²⁺ has not been clarified in detail. We examined the effect of extracellular Mg²⁺ deprivation on a MEK–ERK cascade and cell proliferation using a renal epithelial cell line, Madin-Darby canine kidney (MDCK) cells.Main methodsMDCK cells were cultured in Mg²⁺-containing or Mg²⁺-free media. A HA-tagged constitutively active (CA)-MEK1 and a dominant negative (DN)-MEK1 were transfected into MDCK cells. The level of protein was examined by Western blotting. The intracellular free Mg²⁺ concentration ([Mg²⁺]_i) was measured using a fluorescent dye, mag-fura 2. Cell proliferation was determined by WST-1 assay. Dead cells were identified by staining with annexin V-FITC and propidium iodide.Key findingsIn the presence of fetal calf serum (FCS), Mg²⁺ deprivation decreased phosphorylated-ERK1/2 (p-ERK1/2) levels and [Mg²⁺]_i. Re-addition of Mg²⁺ increased p-ERK1/2 levels, which were inhibited by U0126, a specific inhibitor of a MEK–ERK cascade. Glutathione-S-transferase pull-down and coimmunoprecipitation assays showed that CA-MEK1 and DN-MEK1 binds with ERK1/2 in the presence of Mg²⁺. In contrast, neither CA-MEK1 nor DN-MEK1 bound to ERK1/2 in the absence of Mg²⁺. These results indicate that the MEK–ERK cascade is regulated by [Mg²⁺]_i. Cell proliferation was increased by the treatment with FCS or the expression of CA-MEK1 in the presence of Mg²⁺, but was inhibited by Mg²⁺ deprivation. Mg²⁺ deprivation did not increase the number of dead cells.SignificanceMg²⁺ is involved in the regulation of the MEK–ERK cascade and cell proliferation in MDCK cells.     

Vasoactive intestinal peptide stimulates mucus secretion, but nitric oxide has no effect on mucus secretion in the ferret trachea.

Vasoactive intestinal peptide (VIP) and nitric oxide (NO) are neurotransmitters involved in the regulation of bronchial and pulmonary vascular tone. Published studies of the effects of VIP on airway mucus secretion have yielded conflicting results. The purpose of this study was to determine the effect of VIP on mucus secretion in the ferret trachea and if this effect was influenced by NO. We used a sandwich enzyme-linked lectin assay to measure mucin secretion and a turbidimetric assay to measure lysozyme (serous cell) secretion from ferret tracheal segments. VIP (10(-7) M) increased mucin secretion over 2 h. VIP (10(-9) to 10(-5) M) stimulated mucin secretion in a dose-dependent fashion. VIP-induced mucin secretion was partially blocked by a VIP receptor antagonist (a chimeric VIP-pituitary adenylate cyclase-activating peptide analog, VIP receptor antagonist) at a 10-fold excess concentration. At all concentrations tested, neither NG-nitro-L-arginine methyl ester, an inhibitor of NO synthase, nor S-nitroso-N-acetyl-penicillamine, an NO donor, had any significant effect on constitutive or VIP-induced mucus secretion. We conclude that VIP-stimulated mucin and lysozyme secretion was both time dependent and dose dependent and that NO neither stimulates nor inhibits mucus secretion in the ferret trachea.     

Characterization of the denatured structure of pyrrolidone carboxyl peptidase from a hyperthermophile under nondenaturing conditions: role of the C-terminal alpha-helix of the protein in folding and stability

The cysteine-free pyrrolidone carboxyl peptidase (PCP-0SH) from a hyperthermophile, Pyrococcus furiosus, can be trapped in the denatured state under nondenaturing conditions, corresponding to the denatured structure that exists in equilibrium with the native state under physiological conditions. The denatured state is the initial state (D1 state) in the refolding process but differs from the completely denatured state (D2 state) in the concentrated denaturant. Also, it has been found that the D1 state corresponds to the heat-denatured state. To elucidate the structural basis of the D1 state, H/D exchange experiments with PCP-0SH were performed at pD 3.4 and 4 degrees C. The results indicated that amide protons in the C-terminal alpha6-helix region hardly exchanged in the D1 state with deuterium even after 7 days, suggesting that the alpha6-helix (from Ser188 to Glu205) of PCP-0SH was stably formed in the D1 state. In order to examine the role of the alpha6-helix in folding and stability, H/D exchange experiments with a mutant, A199P, at position 199 in the alpha6-helix region were performed. The alpha6-helix region of A199P in the D1 state was partially unprotected, while some hydrophobic residues were protected against the H/D exchange, although these hydrophobic residues were unprotected in the wild-type protein. These results suggest that the structure of A199P in the D1 state formed a temporary stable denatured structure with a non-native hydrophobic cluster and the unstructured alpha6-helix. Both the stability and the refolding rate decreased by the substitution of Pro for Ala199. We can conclude that the native-like helix (alpha6-helix) of PCP-0SH is already constructed in the D1 state and is necessary for efficient refolding into the native structure and stabilization of PCP-0SH.     

Superoxide radical sensing using a cytochrome c3 immobilized conducting polymer electrode

A biosensor based on cytochrome c3 (cyt c3) has been introduced to detect and quantify superoxide radical (O2*-). Cyt c3, isolated from the sulfate-reducing bacterium (Desulfovibrio vulgaris Miyazaki F. strain), and its mutant were immobilized onto a conducting polymer coated electrodes by the covalent bonding with carbodiimide chemistry. The immobilization of cyt c3 was investigated with quartz crystal microbalance, electrochemical impedance spectroscopy, and cyclic voltammetric studies. The CVs recorded for cyt c3 and a mutant modified-electrodes showed a quasi-reversible behavior having the formal potential of about -471 and -476 mV (versus Ag/AgCl), respectively, in a 0.1M phosphate buffer solution (pH 7.0). The modified electrodes showed the surface controlled process and the electron transfer rate constants (ks) were evaluated to be 0.47 and 0.51 s(-1) for cyt c3 and mutant modified electrodes, respectively. A potential application of the cyt c3 modified electrode was evaluated by monitoring the bioelectrocatalytic response towards the O2*-. The hydrodynamic range of 0.2-2.7 micromole L(-1) and the detection limit of 0.05 micromole L(-1) were obtained.