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There are different methods of discretizing integrable systems. We consider semi-discrete analog of two-dimensional Toda lattices associated to the Cartan matrices of simple Lie algebras that was proposed by Habibullin in 2011. This discretization is based on the notion of Darboux integrability. Generalized Toda lattices are known to be Darboux integrable in the continuous case (that is, they admit complete families of characteristic integrals in both directions). We prove that semi-discrete analogs of Toda lattices associated to the Cartan matrices of all simple Lie algebras are Darboux integrable. By examining the properties of Habibullin's discretization we show that if a function is a characteristic integral for a generalized Toda lattice in the continuous case, then the same function is a characteristic integral in the semi-discrete case as well. We consider characteristic algebras of such integral-preserving discretizations of Toda lattices to prove the existence of complete families of characteristic integrals in the second direction. [ABSTRACT FROM AUTHOR]

The colonization of the Moon and building permanent lunar outposts in the near future has become a main objective for most space agencies around the world. Future lunar outpost with a permanent human presence would have high power requirements to support such activities as scientific experimentation, in situ mining and processing, astronomical observation, and surface exploration. Several challenges are associated with the habitation of the lunar surface, such as, choosing an appropriate power generation unit. Stirling engines are one of the attractive power generation options which were implemented in space missions before, and are most likely to be used in future space exploration missions. In this paper, a detailed calculation methodology of a radiator design in a lunar power plant is developed. A brief research on some of the challenges that are associated with the habitation of the Moon and an overview of a lunar power plant consisting of a free piston Stirling engine (FPSE) are presented. A program code based on the developed calculation methodology consisting of two algorithms (one- and two-dimensional cases) was developed, and the results of both algorithms were compared and presented. Moreover, three different radiator design options having helium as a refrigerant circulating in them were considered and their results were analyzed. Finally, the conclusions and future directions of this work are provided. • Stirling engines are an effective power generation option on the moon. • Solar and Nuclear power should be considered as an energy source on the moon. • A suitable location on the moon should have stable temperature ranges. • Thermophysical properties of the refrigerant affects the work of the radiator. • Hydraulic resistance in the pipes affects the dimensions of the radiator. [ABSTRACT FROM AUTHOR]

Background: Celiac disease (CD) is an autoimmune disorder that occurs in genetically predisposed people and is caused by a reaction to the gluten protein found in wheat, which leads to intestinal villous atrophy. Currently there is no drug for treatment of CD. The only known treatment is lifelong gluten-free diet. The main aim of this work is to develop a mathematical model of the immune response in CD patients and to predict the efficacy of a transglutaminase-2 (TG-2) inhibitor as a potential drug for treatment of CD. Results: A thorough analysis of the developed model provided the following results: 1. TG-2 inhibitor treatment leads to insignificant decrease in antibody levels, and hence remains higher than in healthy individuals. 2. TG-2 inhibitor treatment does not lead to any significant increase in villous area. 3. The model predicts that the most effective treatment of CD would be the use of gluten peptide analogs that antagonize the binding of immunogenic gluten peptides to APC. The model predicts that the treatment of CD by such gluten peptide analogs can lead to a decrease in antibody levels to those of normal healthy people, and to a significant increase in villous area. Conclusions: The developed mathematical model of immune response in CD allows prediction of the efficacy of TG-2 inhibitors and other possible drugs for the treatment of CD: their influence on the intestinal villous area and on the antibody levels. The model also allows to understand what processes in the immune response have the strongest influence on the efficacy of different drugs. This model could be applied in the pharmaceutical R&D arena for the design of drugs against autoimmune small intestine disorders and on the design of their corresponding clinical trials. [ABSTRACT FROM AUTHOR]

Aims Based on indirect methods, it has been suggested that both L- and T-type Ca2+ channels mediate signalling in the renal afferent arteriole and that T-type Ca2+ channels are involved in signalling in the efferent arteriole. However, Ca2+ currents have never been studied in these two vessels. Our study was initiated to directly determine the type of Ca2+ channels in these vessels for the first time, using patch clamp. Methods and results Native myocytes were obtained from individually isolated rat renal afferent and efferent arterioles and from rat tail arteries (TA). TA myocytes, which possess both L- and T-type Ca2+ currents, served as a positive control. Inward Ca2+ and Ba2+ currents (ICa and IBa) were measured in 1.5 mmol/L Ca2+ and 10 mmol/L Ba2+, respectively, using the whole-cell configuration. By exploiting known differences in activation and inactivation characteristics and differing sensitivities to nifedipine and kurtoxin, the presence of both L- and T-type Ca2+ channels in TA myocytes was readily demonstrated. Afferent arteriolar myocytes exhibited relatively large ICa densities (−2.0 ± 0.2 pA/pF) in physiological Ca2+ and the IBa was 3.6-fold greater. These currents were blocked by nifedipine, but not by kurtoxin, and did not exhibit the activation and inactivation characteristics of T-type Ca2+ channels. Efferent arteriolar myocytes did not exhibit a discernible voltage-activated ICa in physiological Ca2+. Conclusion Our findings support the physiological role of L-type Ca2+ channels in the afferent, but not efferent, arteriole, but do not support the premise that functional T-type Ca2+ channels are present in either vessel. [ABSTRACT FROM AUTHOR]

l-isoleucine-4-hydroxylase ( IDO) is a recently discovered member of the Pfam family PF10014 (the former DUF 2257 family) of uncharacterized conserved bacterial proteins. To uncover the range of biochemical activities carried out by PF10014 members, eight in silico-selected IDO homologues belonging to the PF10014 were cloned and expressed in Escherichia coli. l-methionine, l-leucine, l-isoleucine and l-threonine were found to be catalysed by the investigated enzymes, producing l-methionine sulfoxide, 4-hydroxyleucine, 4-hydroxyisoleucine and 4-hydroxythreonine, respectively. An investigation of enzyme kinetics suggested the existence of a novel subfamily of bacterial dioxygenases within the PF10014 family for which free l-amino acids could be accepted as in vivo substrates. A hypothesis regarding the physiological significance of hydroxylated l-amino acids is also discussed. [ABSTRACT FROM AUTHOR]

Aims We investigated the role of the inward rectifier K+ channel (KIR) in the renal interlobular artery (ILA). The ILA supplies the afferent arteriole and ranges in diameter from >100 µm near its origin at the arcuate artery to <30 µm at its most distal segment. Methods and results Vasodilatory responses to elevated extracellular K+ (15 mmol/L) and vasoconstrictor responses due to KIR blockade by Ba2+ (10–100 µmol/L) were assessed in in vitro perfused hydronephrotic rat kidneys. The distal ILA (26 ± 1 µm) exhibited K+-induced dilation and Ba2+-induced vasoconstriction, whereas neither response was observed in the proximal ILA (108 ± 3 µm). The intermediate ILA (55 ± 1 µm) exhibited a modest K+-induced vasodilatation, but no Ba2+-induced vasoconstriction. The K+-induced dilations were blocked by Ba2+, but not by ouabain. Ba2+-induced depolarization, measured in ILA segments from normal kidneys, decreased with the increasing diameter. Patch-clamp studies demonstrated that the KIR current (IKIR) density also was inversely correlated with ILA segment diameter. Myocytes from afferent arterioles and distal ILAs exhibited similarly large IKIR, whereas this current was absent in proximal ILA myocytes. Finally, we found that Ba2+ attenuated myogenic vasoconstriction, suggesting an involvement of IKIR. The previously shown pattern of myogenic reactivity of the ILA (distal > intermediate > proximal) mirrors the distribution of IKIR reported in the present study, further supporting a role for IKIR. Conclusion Our findings indicate differences in the magnitude of IKIR along the ILA and suggest that the influence of KIR on reactivity increases as vessel diameter decreases from proximal to distal regions. [ABSTRACT FROM PUBLISHER]

Abstract: Melamine (2,4,6-triamino-1,3,5-triazine) is a nitrogen-rich chemical implicated in the pet and human food recalls and in the global food safety scares involving milk products. Due to the serious health concerns associated with melamine consumption and the extensive scope of affected products, rapid and sensitive methods to detect melamine''s presence are essential. We propose the use of spectroscopy data-produced by near-infrared (near-IR/NIR) and mid-infrared (mid-IR/MIR) spectroscopies, in particular—for melamine detection in complex dairy matrixes. None of the up-to-date reported IR-based methods for melamine detection has unambiguously shown its wide applicability to different dairy products as well as limit of detection (LOD) below 1ppm on independent sample set. It was found that infrared spectroscopy is an effective tool to detect melamine in dairy products, such as infant formula, milk powder, or liquid milk. ALOD below 1ppm (0.76±0.11ppm) can be reached if a correct spectrum preprocessing (pretreatment) technique and a correct multivariate (MDA) algorithm—partial least squares regression (PLS), polynomial PLS (Poly-PLS), artificial neural network (ANN), support vector regression (SVR), or least squares support vector machine (LS-SVM)—are used for spectrum analysis. The relationship between MIR/NIR spectrum of milk products and melamine content is nonlinear. Thus, nonlinear regression methods are needed to correctly predict the triazine-derivative content of milk products. It can be concluded that mid- and near-infrared spectroscopy can be regarded as a quick, sensitive, robust, and low-cost method for liquid milk, infant formula, and milk powder analysis. [Copyright &y& Elsevier]

Abstract: During the past several years, near-infrared (near-IR/NIR) spectroscopy has increasingly been adopted as an analytical tool in various fields from petroleum to biomedical sectors. The NIR spectrum (above 4000cm−1) of a sample is typically measured by modern instruments at a few hundred of wavelengths. Recently, considerable effort has been directed towards developing procedures to identify variables (wavelengths) that contribute useful information. Variable selection (VS) or feature selection, also called frequency selection or wavelength selection, is a critical step in data analysis for vibrational spectroscopy (infrared, Raman, or NIRS). In this paper, we compare the performance of 16 different feature selection methods for the prediction of properties of biodiesel fuel, including density, viscosity, methanol content, and water concentration. The feature selection algorithms tested include stepwise multiple linear regression (MLR-step), interval partial least squares regression (iPLS), backward iPLS (BiPLS), forward iPLS (FiPLS), moving window partial least squares regression (MWPLS), (modified) changeable size moving window partial least squares (CSMWPLS/MCSMWPLSR), searching combination moving window partial least squares (SCMWPLS), successive projections algorithm (SPA), uninformative variable elimination (UVE, including UVE-SPA), simulated annealing (SA), back-propagation artificial neural networks (BP-ANN), Kohonen artificial neural network (K-ANN), and genetic algorithms (GAs, including GA-iPLS). Two linear techniques for calibration model building, namely multiple linear regression (MLR) and partial least squares regression/projection to latent structures (PLS/PLSR), are used for the evaluation of biofuel properties. A comparison with a non-linear calibration model, artificial neural networks (ANN-MLP), is also provided. Discussion of gasoline, ethanol-gasoline (bioethanol), and diesel fuel data is presented. The results of other spectroscopic techniques application, such as Raman, ultraviolet-visible (UV-vis), or nuclear magnetic resonance (NMR) spectroscopies, can be greatly improved by an appropriate feature selection choice. [Copyright &y& Elsevier]

Aims The aim of this study was to determine the relative importance of Ca2+ sensitization, ion channels, and intracellular Ca2+ ([Ca2+]i) in the mixed constrictor/relaxation actions of superoxide anion on systemic and pulmonary arteries. Methods and results Pulmonary and mesenteric arteries were obtained from rat. Superoxide was generated in arteries and cells with 6-anilino-5,8-quinolinequinone (LY83583). Following pre-constriction with U46619, 10 μmol/L LY83583 caused constriction in pulmonary and relaxation in mesenteric arteries. Both constrictor and relaxant actions of LY83583 were inhibited by superoxide dismutase and catalase. LY83583 caused Rho-kinase-dependent constriction in α-toxin-permeabilized pulmonary but not mesenteric arteries. Phosphorylation of myosin phosphatase-targeting subunit-1 (MYPT-1; as determined by western blot), was enhanced by LY83583 in pulmonary artery only. However, in both artery types, changes in tension were closely correlated with changes in phosphorylation of the 20 kDa myosin light chain as well as changes in [Ca2+]i (as measured with Fura PE-3), with LY83583 causing increases in pulmonary and decreases in mesenteric arteries. When U46619 was replaced by 30 mmol/L K+, all changes in [Ca2+]i were abolished and LY83583 constricted both artery types. The KV channel inhibitor 4-aminopyridine abolished the LY83583-induced relaxation in mesenteric artery without affecting constriction in pulmonary artery. However, LY83583 caused a similar hyperpolarizing shift in the steady-state activation of KV current in isolated smooth muscle cells of both artery types. Conclusions Superoxide only causes Rho-kinase-dependent Ca2+ sensitization in pulmonary artery, resulting in constriction, and whilst it opens KV channels in both artery types, this only results in relaxation in mesenteric. [ABSTRACT FROM AUTHOR]

The stereo-specific l-isoleucine-4-hydroxylase ( l-isoleucine dioxygenase (IDO)) was cloned and expressed in an Escherichia coli 2Δ strain lacking the activities of α-ketoglutarate dehydrogenase (EC 1.2.4.2), isocitrate liase (EC 4.1.3.1), and isocitrate dehydrogenase kinase/phosphatase (EC 2.7.11.5). The 2Δ strain could not grow in a minimal-salt/glucose/glycerol medium due to the blockage of TCA during succinate synthesis. The IDO activity in the 2Δ strain was able to “shunt” destroyed TCA, thereby coupling l-isoleucine hydroxylation and cell growth. Using this strain, we performed the direct biotransformation of l-isoleucine into 4-HIL with an 82% yield. [ABSTRACT FROM AUTHOR]

Abstract: The unique function of 4-hydroxyisoleucine (4-HIL) is to stimulate glucose-induced insulin secretion in a glucose-dependent manner. 4-HIL is distributed only in certain kinds of plants and mushrooms, but the biosynthetic mechanism of 4-HIL has not been elucidated. Moreover, 4-HIL-producing microorganisms have not been reported. l-isoleucine (l-Ile) hydroxylating activity producing 4-HIL was detected in a cell lysate of Bacillus thuringiensis strain 2e2 AKU 0251 obtained from the mid-late exponential phase of growth. Properties of the purified hydroxylase demonstrated that it is a α-ketoglutaric acid (α-KG) dependent l-Ile dioxygenase (IDO) and requires α-KG, ferric ion, and ascorbic acid for its maximum activity. IDO showed high stereoselectivity in l-Ile hydroxylation producing only (2S,3R,4S)-4-HIL. The N-terminal 22 amino acids sequence revealed high homology to a hypothetical protein (GenBank ID: RBTH_06809) in B. thuringiensis serovar israelensis ATCC 35646. The histidine motif, which is conserved in α-KG dependent dioxygenases, is found in RBTH_06809. [Copyright &y& Elsevier]

El-Awady MS, Smirnov SV, Watson ML. Voltage-independent calcium channels mediate lipopolysaccharide-inducëd hyporeactivity to endothelin-l in the rat aorta. Am J Physiol Heart Circ Physiol 296: H1408-H1415, 2009. First published March 13, 2009; doi:l0.l 152/ajpheart.01305.2008.-The roles of intracellu1ar calcium concentration ([Ca[sup2+]]1) and Ca[sup2+] sensitization in lipopolysaccharide (LPS)-induced vascular smooth muscle (VSM) hyporesponsiveness are incompletely understood. To investigate these roles, contraction responses to endothelin-l (ET-1) and 80 mM KCI; relaxation responses to nifedipine; the expression levels of mRNAs of ET-l and its receptors (ETA or ETB); the expression levels of protein kinase C (PKC) and phosphorylation of Rho kinase (ROKα), CPI-17, and myosin phosphatase target subunit-i (MYPT1); and changes in aortic VSM cell [Ca[sup2+]][subi] were measured in LPS-treated aortic rings from male Wistar rats (250-300 g). LPS (10 μg/ml, 20 h) decreased contraction induced by ET-l (0.3-100 nM) or 80 mM KCl. LPSinduced hypocontractility was not observed in the absence of external Ca[sup2+] but LPS-treated aorta remained hypocontractile on subsequent stepwise restoration of extracellular Ca[sup2+] (0.01-10 mM). Vascular relaxation to nifedipine; mRNA expression levels of ET1, ET[subA], or ET[subB] protein expression levels of PKC; and phosphorylation levels of ROKa, CPI-17, and MYPT1 were not affected by LPS. In isolated aortic VSM cells, ET-1 caused a transient initial increase iii [Ca[sup2+]][subi], followed by a maintained tonic increase in [Ca[sup2+]][subi], which was decreased by LPS pretreatment and was dependent on external Ca[sup2+]. Subsequent restoration of extracellular Ca[sup2+] increased [Ca[sup2+]][subi], but this increase was lower in the LPS-treated group. This difference in response to extracellular Ca[sup2+] addition was not affected by diltiazem, but was abolished by SKF-96365. Therefore, LPS induces hyporeactivity to ET-l in rat aorta that depends on external Ca[sup2+] influx through non-voltage-operated Ca[sup2+] channels, but not on ET-1 receptor expression or Ca[sup2+] sensitization. [ABSTRACT FROM AUTHOR]

The RE-1 silencer of transcription (REST) is a transcriptional regulator that represses neuron-specific genes in non-neuronal tissues by remodeling chromatin structure. We have utilized human mesenchymal stem cells (MSCs) as a research tool to understand the molecular mechanisms that regulate a neurogenic program of differentiation in non-neuronal tissue. MSCs are mesoderm-derived cells that generate specialized cells such as stroma, fat, bone, and cartilage. We have reported previously the transdifferentiation of MSCs into functional neuronal cells (Cho, K. J., Trzaska, K. A., Greco, S. J., McArdle, J., Wang, F. S., Ye, J.-H., and Rameshwar, P. (2005) Stem Cells 23, 383-391). Expression of the neurotransmitter gene TAC1 was detected only in neuronal cells and thus served as a model to study transcriptional regulation of neuron-specific genes in undifferentiated MSCs. Bone marrow stromal cells are known to transiently express TAC1 following stimulation with the microenvironmental factor interleukin-1α. We thus compared the effects of interleukin-1α stimulation and neuronal induction of MSCs on TAC1 regulation. Transcription factor mapping of the 5′-flanking region of the TAC1 promoter predicted two REST-binding sites adjacent to one NFκB site within exon 1. Chromatin immunoprecipitation, mutagenesis, and loss-of-function studies showed that both transcription factors synergistically mediated repression of TAC1 in the neurogenic and microenvironmental models. Together, the results support the novel finding of synergism between REST and NFκB in the suppression of TAC1 in non-neuronal cells. [ABSTRACT FROM AUTHOR]

A two-step enzymatic synthesis process of 4-hydroxyisoleucine is suggested. In the first step, the aldol condensation of acetaldehyde and α-ketobutyrate catalyzed by specific aldolase results in the formation of 4-hydroxy-3-methyl-2-keto-pentanoate (HMKP). In the second step, amination of HMKP by the branched-chain amino acid aminotransferase leads to synthesis of 4-hydroxyisoleucine. An enzyme possessing HMKP aldolase activity (asHPAL) was purified 2500-fold from a crude extract of Arthrobacter simplex strain AKU 626. Sequencing of the asHPAL structural gene showed that the purified enzyme belongs to the HpcH/HpaI aldolase family. The 4-hydroxyisoleucine was synthesized in vitro from acetaldehyde, α-ketobutyrate andl-glutamate using a coupled aldolase/branched-chain amino acid aminotransferase bienzymatic reaction. [ABSTRACT FROM AUTHOR]

Type I (IFN-α/β) and type III (IFN-λs) IFNs are important components of the host antiviral response. Although type Ill IFNs possess intrinsic antiviral activity similar to that of type I IFNs, they signal through a specific unique receptor complex, and their functional importance for antiviral resistance is largely uncharacterized. Here, we report the first virus defense mechanism that directly targets type Ill IFNs. Y136 from Yaba-like disease virus, a yatapoxvirus, is a secreted glycoprotein related to protein B18 from Vaccinia virus, a known type I IFN-binding protein and a member of the Ig superfamily. Surprisingly, whereas B18 inhibits only type I IFNs, Y136 inhibits both type land type Ill IFN5. Y136 inhibits IFN-induced signaling and suppresses IFN-mediated biological activities including up-regulation of MHC class I antigen expression and induction of the antiviral state. These data demonstrate that poxviruses have developed unique strategies to counteract IFN-mediated antiviral protection and highlight the importance of type Ill IFNs in antiviral defense. These results suggest that type III IFNs may be an effective treatment for some poxviral infections. [ABSTRACT FROM AUTHOR]

Abstract: Mesenchymal stem cells (MSCs) in bone marrow (BM) regulate the differentiation and proliferation of adjacent hematopoietic precursor cells and contribute to the regeneration of mesenchymal tissues, including bone, cartilage, fat and connective tissue. BM is an important site for the pathogenesis of human cytomegalovirus (HCMV) where the virus establishes latency in hematopoietic progenitors and can transmit after reactivation to neighboring cells. Here we demonstrate that BM-MSCs are permissive to productive HCMV infection, and that HCMV alters the function of MSCs: (i) by changing the repertoire of cell surface molecules in BM-MSCs, HCMV modifies the pattern of interaction between BM-MSCs and hematopoietic cells; (ii) HCMV infection of BM-MSCs undergoing adipogenic or osteogenic differentiation impaired the process of differentiation. Our results suggest that by altering BM-MSC biology, HCMV may contribute to the development of various diseases. [Copyright &y& Elsevier]

Abstract: γ-Aminobutyraldehyde dehydrogenase (ABALDH) from wild-type E. coli K12 was purified to apparent homogeneity and identified as YdcW by MS-analysis. YdcW exists as a tetramer of 202±29kDa in the native state, a molecular mass of one subunit was determined as 51±3kDa. K m parameters of YdcW for γ-aminobutyraldehyde, NAD+ and NADP+ were 41±7, 54±10 and 484±72μM, respectively. YdcW is the unique ABALDH in E. coli K12. A coupling action of E. coli YgjG putrescine transaminase and YdcW dehydrogenase in vitro resulted in conversion of putrescine into γ-aminobutyric acid. [Copyright &y& Elsevier]

We characterized the effects of intracellular Mg2+ (Mg2+i) on potassium currents mediated by the Kv1.5 and Kv2.1 channels expressed inXenopusoocytes. Increase in Mg2+i caused a voltage-dependent block of the current amplitude, apparent acceleration of the current kinetics (explained by a corresponding shift in the steady-state activation) and leftward shifts in activation and inactivation dependencies for both channels. The voltage-dependent block was more potent for Kv2.1 [dissociation constant at 0 mV,Kd(0), was ~70 mM and the electric distance of the Mg2+ binding site,d, was 0.2] than for the Kv1.5 channel [Kd(0)~40 mM andd=0.1]. Similar shifts in the voltage-dependent parameters for both channels were described by the Gouy-Chapman formalism with the negative charge density of 1 e-/100 Å2. Additionally, Mg2+i selectively reduced a non-inactivating current and increased the accumulation of inactivation of the Kv1.5, but not the Kv2.1 channel. A potential functional role of the differential effects of Mg2+i on the Kv channels is discussed. [ABSTRACT FROM AUTHOR]

Background: Putrescine is the intermediate product of arginine decarboxylase pathway in Escherichia coli which can be used as an alternative nitrogen source. Transaminase and dehydrogenase enzymes seem to be implicated in the degradative pathway of putrescine, in which this compound is converted into γ-aminobutyrate. But genes coding for these enzymes have not been identified so far. Results: The 1.8-kbp DNA fragment containing E. coli K12 ygjG gene with aer-ygjG intergenic region was examined. It was found that the fragment contains σ54-depended open reading frame (ORF) of 1,380 nucleotides encoding a 459-amino acid polypeptide of approximately 49.6 kDa. The cytidine (C) residue localized 10 bp downstream of the σ54 promoter sequence was identified as the first mRNA base. The UUG translation initiation codon is situated 36 nucleotides downstream of the mRNA start. The YgjG was expressed as a his6-tag fused protein and purified to homogeneity. The protein catalyzed putrescine:2-oxoglutaric acid (2-OG) aminotransferase reaction (PATase, EC 2.6.1.29). The Km values for putrescine and 2-OG were found to be 9.2 mM and 19.0 mM, respectively. The recombinant enzyme also was able to transaminate cadaverine and, in lower extent, spermidine, and gave maximum activity at pH 9.0. Conclusion: Expression of E. coli K12 ygjG coding region revealed σ54-depended ORF which encodes a 459-amino acid protein with putrescine:2-OG aminotransferase activity. The enzyme also was able to transaminate cadaverine and, in lower extent, spermidine. [ABSTRACT FROM AUTHOR]

Reports a study which investigated the mechanism of the modulation of L-type calcium channels by extracellular protons in smooth muscle cells isolated from human mesenteric arteries. Effects of acidification and alkalinization on activation and inactivation of L-type calcium currents; Effects of acidification and alkalinization on the calcium channel current in high calcium and barrium-containing solutions; Effects of changing pH on the calcium currents.

Examines the association of chronic hypoxia with reduced delayed rectifier K+ current in rat pulmonary artery muscle cells. Causes of pulmonary hypertension due to long term hypoxia; Depolarization of pulmonary artery (PA) smooth muscle cells (SMC); Membrane potential by delayed rectifier and adenosine triphosphate (ATP)-dependent K+ currents.

Examines the alteration of transmembrane potassium gradient during the development of delayed rectifier in isolated rat pulmonary arterial (PA) cells. Properties of tail currents; Morphology and passive membrane properties of isolated PA cells; Separation of outward potassium currents; Effects of removal of extracellular potassium and sodium.

Crystal structure of the ternary complex of human IL-24 with two receptors, IL-22R1 and IL-20R2, has been determined at 2.15 Å resolution. A crystallizable complex was created by a novel approach involving fusing the ligand with a flexible linker to the presumed low-affinity receptor, and coexpression of this construct in Drosophila S2 cells together with the presumed high-affinity receptor. This approach, which may be generally applicable to other multiprotein complexes with low-affinity components, was necessitated by the instability of IL-24 expressed by itself in either bacteria or insect cells. Although IL-24 expressed in Escherichia coli was unstable and precipitated almost immediately upon its refolding and purification, a small fraction of IL-24 remaining in the folded state was shown to be active in a cell-based assay. In the crystal structure presented here, we found that two cysteine residues in IL-24 do not form a predicted disulfide bond. Lack of structural restraint by disulfides, present in other related cytokines, is most likely reason for the low stability of IL-24. Although the contact area between IL-24 and IL-22R1 is larger than between the cytokine and IL-20R2, calculations show the latter interaction to be slightly more stable, suggesting that the shared receptor (IL-20R2) might be the higher-affinity receptor. [ABSTRACT FROM AUTHOR]

The authors discuss the study "Na+ Channel Regulation by Ca2+/Calmodulin and Ca2+Calmodulin-Dependent Protein Kinase II in Guinea-pig Ventricular Mycocytes," by T. Alba and colleagues. According to the authors, a number of ion channels is regulated by Ca2+-binding protein calmodulin (CaM). They also talk about voltage-gated sodium channels (VGSCs).

Mesoporous hydroxyapatite (HA) materials demonstrate advantages as catalysts and as support systems for catalysis, as adsorbent materials for removing contamination from soil and water, and as nanocarriers of functional agents for bone-related therapies. The present research demonstrates the possibility of the enlargement of the Brunauer–Emmett–Teller specific surface area (SSA), pore volume, and average pore diameter via changing the synthesis medium and ripening the material in the mother solution after the precipitation processes have been completed. HA powders were investigated via chemical analysis, X-ray diffraction analysis, Fourier-transform IR spectroscopy, transmission electron microscopy (TEM), and scanning (SEM) electron microscopy. Their SSA, pore volume, and pore-size distributions were determined via low-temperature nitrogen adsorption measurements, the zeta potential was established, and electron paramagnetic resonance (EPR) spectroscopy was performed. When the materials were synthesized in water–ethanol and water–acetone media, the SSA and total pore volume were 52.1 m2g−1 and 116.4 m2g−1, and 0.231 and 0.286 cm3g−1, respectively. After ripening for 21 days, the particle morphology changed, the length/width aspect ratio decreased, and looser and smaller powder agglomerates were obtained. These changes in their characteristics led to an increase in SSA for the water and water–ethanol samples, while pore volume demonstrated a multiplied increase for all samples, reaching 0.593 cm3g−1 for the water–acetone sample. [ABSTRACT FROM AUTHOR]

The Euro-Siberian steppe flora consists of warm- and cold-adapted species, which may have responded differently to Pleistocene glacials and interglacials. Genotyping-by-sequencing individuals from across the distribution range of the pheasant's eye (Adonis vernalis), we aimed to gain insight into steppe florogenesis based on the species' evolutionary history. Although the primary area of origin of the species group comprising A. vernalis, A. villosa and A. volgensis is in Asia, our results indicate that recent populations of A. vernalis are not of Asian origin but evolved in the southern part of Europe during the Pleistocene, with Spanish populations clearly genetically distinct from the Southeastern European populations. We inferred that A. vernalis migrated eastwards from the sub-Mediterranean forest-steppes of Southeastern Europe into the continental forest-steppe zone. Eastern European populations had the highest private allelic richness, indicating long-term large population sizes in this region. As a thermophilic species, A. vernalis seems unlikely to have survived in the cold deserts of the Last Glacial Maximum in Western Siberia, so this region was likely (re)colonized postglacially. Overall, our results reinforce the importance of identifying the area of origin and the corresponding ecological requirements of steppe plants in order to understand the composition of today's steppe flora. [ABSTRACT FROM AUTHOR]

Hypoxia-mediated inhibition of voltage-gated K+ (Kv) channels plays an important role in hypoxic pulmonary vasoconstriction. The exact mechanisms of this effect remain not completely understood. The effect of hypoxia on Kv channel currents (IKv) in pulmonary arterial myocytes (PAMs) was investigated using the patch clamp technique. Inhibition of IKv was calculated as a percentage of the block of the whole cell conductance calculated from current-voltage relationships measured with a 2 s voltage ramp. When PAMs were bathed in a bicarbonate buffered physiological saline solution (PSS), hypoxia blocked IKv by 51±8% (n=6). When PAMs were bathed in HEPES buffered PSS the effect of hypoxia was virtually abolished. This difference could suggest the importance of mechanisms activated in the physiological conditions in the regulation of IKv. Since the Na+-H+ exchanger (NHX) could be one of such mechanisms, the effect of amiloride (100 μM) and the NHX specific inhibitor MIA (25 μM) was studied. Both amiloride and MIA significantly attenuated hypoxia-induced block of IKv (19±5%, n=8 and 20±6%, n=7, respectively, p<0.01). The role of the NHX in the regulation of IKv was further assessed in HEPES buffered PSS using the NHX inhibitors, different pH gradients and intracellular pipette solutions, and removal of extracellular sodium. The role of the NHX in the regulation of Kv channels in PAMs is discussed. Supported by the BHF. [ABSTRACT FROM AUTHOR]

Little research exists on extending ex-vivo systems to large animal nerves, and to the best of our knowledge, there has yet to be a study comparing these against in-vivo data. This paper details the first ex-vivo system for large animal peripheral nerves to be compared with in-vivo results. Detailed ex-vivo and in-vivo closed-loop neuromodulation experiments were conducted on pig ulnar nerves. Temperatures from 20 °C to 37 °C were evaluated for the ex-vivo system. The data were analysed in the time and velocity domains, and a regression analysis established how evoked compound action potential amplitude and modal conduction velocity (CV) varied with temperature and time after explantation. Pig ulnar nerves were sustained ex-vivo up to 5 h post-explantation. CV distributions of ex-vivo and in-vivo data were compared, showing closer correspondence at 37 °C. Regression analysis results also demonstrated that modal CV and time since explantation were negatively correlated, whereas modal CV and temperature were positively correlated. Previous ex-vivo systems were primarily aimed at small animal nerves, and we are not aware of an ex-vivo system to be directly compared with in-vivo data. This new approach provides a route to understand how ex-vivo systems for large animal nerves can be developed and compared with in-vivo data. The proposed ex-vivo system results were compared with those seen in-vivo, providing new insights into large animal nerve activity post-explantation. Such a system is crucial for complementing in-vivo experiments, maximising collected experimental data, and accelerating neural interface development. • We present the first large animal nerve ex-vivo system compared to in-vivo data. • The ex-vivo system successfully sustained pig ulnar nerves for up to five hours. • Nerve activity ex-vivo at 37 °C showed improved correspondence with in-vivo results. • The modal nerve conduction velocity increased with temperature. • The modal nerve conduction velocity decreased with time since explanting the nerve. [ABSTRACT FROM AUTHOR]

Two genera new to China, Fibigia and Pachyneurum and 10 species found in China for the first time, Puccinellia kalininae, Stellaria pulvinata, Nanophyton mongolicum, Capsella orienalis, Pachyneurum grandiflorum, Fibigia spathulata, Craniospermum tuvinicum, Euphrasia schischkinii, E. syreitschikovii, Veronica schmakovii along with 3 species previously unknown in Xinjiang, Rorippa indica, Acalypha australis, and Phalaris canariensis, found in northwest Xinjiang are reported. In addition, the distribution of two species in China is corrected: Lepidium densiflorum is firstly reported for Nei Mongol while the occurrence of Draba sibirica in Gansu is not confirmed. Results of floristic studies by the Chinese-Russian Altai expedition during 2004-2007 are also summarized including 34 species and 1 subspecies revealed as new for China; 7 species confirmed to occur in China; one genus and 5 species not confirmed for China, as well as a number of new records for various provinces, mostly Xinjiang. [ABSTRACT FROM AUTHOR]

4-Hydroxyisoleucine (HIL) found in fenugreek seeds has insulinotropic and anti-obesity effects and is expected to be a novel orally active drug for insulin-independent diabetes. Here, we show that the newly isolated strain Bacillus thuringiensis 2e2 and the closely related strain B. thuringiensis ATCC 35646 operate a novel metabolic pathway for l-isoleucine ( l-Ile) via HIL and 2-amino-3-methyl-4-ketopentanoic acid (AMKP). The HIL synthesis was catalyzed stereoselectively by an α-ketoglutaric acid-dependent dioxygenase and to be useful for efficient production of a naturally occurring HIL isomer, (2 S,3 R,4 S)-HIL. The (2 S,3 R,4 S)-HIL was oxidized to (2 S,3 R) -AMKP by a NAD-dependent dehydrogenase. The metabolic pathway functions as an effective bypass pathway that compensates for the incomplete tricarboxylic acid (TCA) cycle in Bacillus species and also explains how AMKP, a vitamin B antimetabolite with antibiotic activity, is synthesized. These novel findings pave a new way for the commercial production of HIL and also for AMKP. [ABSTRACT FROM AUTHOR]

Voltage-gated K[sup+] (Kv) channels are important in the regulation of pulmonary vascular function having both physiological and pathophysiological implications. The pulmonary vasculature is essential for reoxygenation of the blood, supplying oxygen for cellular respiration. Mitochondria have been proposed as the major oxygen-sensing organelles in the pulmonary vasculature. Using electrophysiological techniques and immunofluorescence, an interaction of the mitochondria with Kv channels was investigated. Inhibitors, blocking the mitochondrial electron transport chain at different complexes, were shown to have a dual effect on Kv currents in freshly isolated rat pulmonary arterial smooth muscle cells (PASMCs). These dual effects comprised an enhancement of Kv current in a negative potential range (manifested as a 5- to 14-mV shift in the Kv activation to more negative membrane voltages) with a decrease in current amplitude at positive potentials. Such effects were most prominent as a result of inhibition of Complex Ill by antimycin A. Investigation of the mechanism of antimycin A-mediated effects on Kv channel currents (I[subKv]) revealed the presence of a mitochondria-mediated Mg[sup2+] ATP-dependent regulation of Kv channels in PASMCs, which exists in addition to that currently proposed to be caused by changes in intracellular reactive oxygen species. [ABSTRACT FROM AUTHOR]

The glycoprotein B (gB) of Aujeszky''s disease virus (ADV) has a role in virus entry and cell-to-cell spread. In this report we examined the cell-binding properties of native ADV gB purified from the virus envelope by affinity chromatography. The binding of gB to the surface of susceptible cells BHK-21 and MDBK was specific, dose-dependent, and nearly saturable, which is characteristic of conventional receptor-ligand interactions. The purified gB was shown to specifically bind to immobilised heparin. The addition of soluble exogenous heparin and heparinase treatment of cells inhibited the binding of gB to the cells. Cell-associated gB could also be dissociated from the cells by soluble heparin. The results indicated that ADV gB binds specifically to cellular heparan sulphate. The binding of gB to cells inhibited the attachment of virus to cells and thus the formation of viral plaques. The results suggest that ADV gB may have a function in the initial attachment of ADV to the surface of susceptible cells. [Copyright &y& Elsevier]

Finding morphological differences between cytotypes that are stable throughout their geographical range is important for understanding evolution of polyploid complexes. The ancient monocot lineage Acorus includes two groups, of which A. calamus s.l. , an important medicinal plant, is a polyploid complex with a centre of diversity in Asia. European plants are sterile triploids introduced by humans. An early study suggested that plants from temperate Asia are tetraploids, but subsequent work revealed diploids and triploids rather than tetraploids in Asiatic Russia; however, cytotype diversity in Western Siberia is insufficiently known. We document the occurrence of diploids and triploids in Western Siberia. Triploids that do not differ in genome size from European Acorus are abundant in the valley of the river Ob where the ability for extensive vegetative propagation provides ecological advantages. An isolated population of aneuploid triploids with 33 chromosomes is found outside the Ob valley. Flow cytometry provides an efficient tool for identification of aneuploid plants in Acorus. All triploids are sterile, but their flowers develop uniform parthenocarpic fruits. Fruits of diploids usually vary in size within a spadix depending on the number of developing seeds. In contrast to North America, where the native diploid plants differ from the introduced triploids by the absence of a secondary midrib of the ensiform leaf blade, Siberian diploids are similar to triploids in possessing a secondary midrib. We confirm that diploids differ from triploids in the size of air lacunae in leaves, which is determined by cell number rather than cell size in septa of aerenchyma. A combination of spathe width and spadix length measured after the male stage of anthesis shows different (slightly overlapping) patterns of variation between diploids and triploids in our material. [ABSTRACT FROM AUTHOR]

The dehydroshikimate dehydratase (DSD) from Corynebacterium glutamicum encoded by the qsuB gene is related to the previously described QuiC1 protein (39.9% identity) from Pseudomonas putida. Both QuiC1 and QsuB are two-domain bacterial DSDs. The N-terminal domain provides dehydratase activity, while the C-terminal domain has sequence identity with 4-hydroxyphenylpyruvate dioxygenase. Here, the QsuB protein and its N-terminal domain (N-QsuB) were expressed in the T7 system, purified and characterized. QsuB was present mainly in octameric form (60%), while N-QsuB had a predominantly monomeric structure (80%) in aqueous buffer. Both proteins possessed DSD activity with one of the following cofactors (listed in the order of decreasing activity): Co2+, Mg2+, Mn2+. The Km and kcat values for the QsuB enzyme (Km ~ 1 mM, kcat ~ 61 s-1) were two and three times higher than those for N-QsuB. 3,4-DHBA inhibited QsuB (Ki ~ 0.38 mM, Ki' ~ 0.96 mM) and N-QsuB (Ki ~ 0.69 mM) enzymes via mixed and noncompetitive inhibition mechanism, respectively. E. coli MG1655ΔaroEPlac‒qsuB strain produced three times more 3,4-DHBA from glucose in test tube fermentation than the MG1655ΔaroEPlac‒n-qsuB strain. The C-terminal domain activity towards 3,4-DHBA was not established in vitro. This domain was proposed to promote protein oligomerization for maintaining structural stability of the enzyme. The dimer formation of QsuB protein was more predictable (ΔG = ‒15.8 kcal/mol) than the dimerization of its truncated version N-QsuB (ΔG = ‒0.4 kcal/mol). [ABSTRACT FROM AUTHOR]

Abstract Advanced glycation end-products (AGEs) play a pivotal role in macro- and micro-vascular diabetic complications. We investigated the mechanism by which methylglyoxal (an endogenous generator of AGEs) affects vascular contractility using the isolated artery technique. Contractile responses to vasoconstrictors phenylephrine (PE), angiotensin II (Ang II), vasopressin (VP) and KCl were measured in the isolated rat aorta following one-our exposure to methylglyoxal (50–200 μM). The perfused rat kidney was employed to confirm the effect of methylglyoxal on microvessels. Methylglyoxal-induced changes in cytosolic calcium were measured in the smooth muscle layer of the aorta with the calcium-sensing fluorophore Fluo-4 AM. Methylglyoxal significantly increased maximal contraction of the rat aorta to PE, Ang II and VP. Similar results were seen in response to the depolarizing vasoconstrictor KCl in macro and micro vessels. The methylglyoxal-induced increases in aortic contraction mediated by the agonist and KCl were endothelium independent. Methylglyoxal-induced increases in KCl-dependent aortic contraction were abolished after the removal of extracellular calcium or in the presence of the calcium channel blocker nifedipine. Incubation with the antioxidant N -acetyl- l -cysteine (NAC), apocynin (a nonselective NADPH oxidase (NOX) inhibitor) or chelerythrine (a protein kinase C (PKC) inhibitor) prior to methylglyoxal pre-treatment reversed the methylglyoxal-induced increases in the rat aortic contractility. In conclusion, the formation of AGEs increases vasoconstriction of both macro- and micro-vessels by increasing the voltage-activated calcium entry in vascular smooth muscles in a NOX and PKC dependent manner. [ABSTRACT FROM AUTHOR]

Germinating spores were obtained from a pentaploid Cystopteris fragilis collected in Mongolian Altai. DNA content of nuclei in gametophytes showed for the first time that gametophytes that developed from spores of the pentaploid sporophyte had a larger number of genomes than those of the mother sporophyte, and some appeared to be decaploid. Fertile decaploid (10n) spores may be produced in the pentaploid C. fragilis and derived from monad spores observed in sporogenesis. Antheridia were produced on the 10n gametophytes, although antherozooids with swimming ability were not observed. Archegonia were not observed. Apogamous sporophytes with 10n genome content were induced from decaploid gametophytes. The monad spores produced may contribute to the formation of higher polyploid sporophyte series in ferns. [ABSTRACT FROM AUTHOR]

Type I (IFN-α/β) and type III (IFN-λ) interferons (IFNs) exert shared antiviral activities through distinct receptors. However, their relative importance for antiviral protection of different organ systems against specific viruses remains to be fully explored. We used mouse strains deficient in type-specific IFN signaling, STAT1 and Rag2 to dissect distinct and overlapping contributions of type I and type III IFNs to protection against homologous murine (EW-RV strain) and heterologous (non-murine) simian (RRV strain) rotavirus infections in suckling mice. Experiments demonstrated that murine EW-RV is insensitive to the action of both types of IFNs, and that timely viral clearance depends upon adaptive immune responses. In contrast, both type I and type III IFNs can control replication of the heterologous simian RRV in the gastrointestinal (GI) tract, and they cooperate to limit extra-intestinal simian RRV replication. Surprisingly, intestinal epithelial cells were sensitive to both IFN types in neonatal mice, although their responsiveness to type I, but not type III IFNs, diminished in adult mice, revealing an unexpected age-dependent change in specific contribution of type I versus type III IFNs to antiviral defenses in the GI tract. Transcriptional analysis revealed that intestinal antiviral responses to RV are triggered through either type of IFN receptor, and are greatly diminished when receptors for both IFN types are lacking. These results also demonstrate a murine host-specific resistance to IFN-mediated antiviral effects by murine EW-RV, but the retention of host efficacy through the cooperative action by type I and type III IFNs in restricting heterologous simian RRV growth and systemic replication in suckling mice. Collectively, our findings revealed a well-orchestrated spatial and temporal tuning of innate antiviral responses in the intestinal tract where two types of IFNs through distinct patterns of their expression and distinct but overlapping sets of target cells coordinately regulate antiviral defenses against heterologous or homologous rotaviruses with substantially different effectiveness. [ABSTRACT FROM AUTHOR]

New magnesium-substituted bone cements containing MgO as a separate phase have been developed and demonstrated enhanced mechanical properties and cytological compatibility. [ABSTRACT FROM AUTHOR]

Aims Sphingosylphosphorylcholine (SPC) elicits vasoconstriction at micromolar concentrations. At lower concentrations (≤1 μmol/L), however, it does not constrict intrapulmonary arteries (IPAs), but strongly potentiates vasoreactivity. Our aim was to determine whether this also occurs in a systemic artery and to delineate the signalling pathway. Methods and results Rat mesenteric arteries and IPAs mounted on amyographwere challenged with ~25 mmol/L [K+] to induce a small vasoconstriction. SPC (1 mmol/L) dramatically potentiated this constriction in all arteries by ~400%. The potentiation was greatly suppressed or abolished by inhibition of phospholipase C (PLC; U73122), PKC1 (inhibitory peptide), Src (PP2), and NADPH oxidase (VAS2870), and also by Tempol (superoxide scavenger), but not by inhibition of Rho kinase (Y27632). Potentiation was lost in mesenteric arteries from p47phox-/-, but not NOX2-/-, mice. The intracellular superoxide generator LY83583 mimicked the effect of SPC. SPC elevated reactive oxygen species (ROS) in vascular smooth muscle cells, and this was blocked by PP2, VAS2870, and siRNA knockdownof PKC1. SPC (1 mmol/L) significantly reduced the EC50 for U46619-induced vasoconstriction, an action ablated by Tempol. In patch-clamped mesenteric artery cells, SPC (200 nmol/L) enhanced Ba2+ current through L-type Ca2+ channels, an action abolished by Tempol but mimicked by LY83583. Conclusion Our results suggest that low concentrations of SPC activate a PLC-coupled and NOX1-mediated increase in ROS, with consequent enhancement of voltage-gated Ca2+ entry and thus vasoreactivity.We speculate that this pathway is not specific for SPC, but may also contribute to vasoconstriction elicited by other G-protein coupled receptor and PLC-coupled agonists. [ABSTRACT FROM AUTHOR]

A novel enzymatic production system of optically pure β-hydroxy α-amino acids was developed. Two enzymes were used for the system: an N-succinyl L-amino acid β-hydroxylase (SadA) belonging to the iron(II)/α-ketoglutarate-dependent dioxygenase superfamily and an N-succinyl L-amino acid desuccinylase (LasA). The genes encoding the two enzymes are part of a gene set responsible for the biosynthesis of peptidyl compounds found in the Burkholderia ambifaria AMMD genome. SadA stereoselectively hydroxylated several N-succinyl aliphatic L-amino acids and produced N-succinyl β-hydroxy L-amino acids, such as N-succinyl- L-β-hydroxyvaline, N-succinyl- L-threonine, (2 S,3 R)- N-succinyl- L-β-hydroxyisoleucine, and N-succinyl- L- threo-β-hydroxyleucine. LasA catalyzed the desuccinylation of various N-succinyl- L-amino acids. Surprisingly, LasA is the first amide bond-forming enzyme belonging to the amidohydrolase superfamily, and has succinylation activity towards the amino group of L-leucine. By combining SadA and LasA in a preparative scale production using N-succinyl- L-leucine as substrate, 2.3 mmol of L- threo-β-hydroxyleucine were successfully produced with 93% conversion and over 99% of diastereomeric excess. Consequently, the new production system described in this study has advantages in optical purity and reaction efficiency for application in the mass production of several β-hydroxy α-amino acids. [ABSTRACT FROM AUTHOR]

TYRO3, AXL, and MER receptors (TAMs) are three homologous type I receptor-tyrosine kinases that are activated by endogenous ligands, protein S (PROS1) and growth arrest-specific gene 6 (GAS6). These ligands can either activate TAMs as soluble factors, or, in turn, opsonize phosphatidylserine (PS) on apoptotic cells (ACs) and serve as bridging molecules between ACs and TAMs. Abnormal expression and activation of TAMs have been implicated in promoting proliferation and survival of cancer cells, as well as in suppressing anti-tumor immunity. Despite the fact that TAM receptors share significant similarity, little is known about the specificity of interaction between TAM receptors and their ligands, particularly in the context of ACs, and about the functional diversity of TAM receptors. To study ligand-mediated activation of TAMs, we generated a series of reporter cell lines expressing chimeric TAM receptors. Using this system, we found that each TAM receptor has a unique pattern of interaction with and activation by GAS6 and PROS1, which is also differentially affected by the presence of ACs, PS-containing lipid vesicles and enveloped virus. We also demonstrated that γ-carboxylation of ligands is essential for the full activation of TAMs and that soluble immunoglobulin-like TAM domains act as specific ligand antagonists. These studies demonstrate that, despite their similarity, TYRO3, AXL, and MER are likely to perform distinct functions in both immunoregulation and the recognition and removal of ACs. [ABSTRACT FROM AUTHOR]

Abstract: Asymmetric sulfoxidation of sulfur-containing l-amino acids was successfully achieved through bioconversion using IDO, which is an Fe(II)/α-ketoglutarate-dependent dioxygenase previously found in Bacillus thuringiensis strain 2e2. The IDO catalyzed sulfoxidation of l-methionine, l-ethionine, S-methyl-l-cysteine, S-ethyl-l-cysteine, and S-allyl-l-cysteine into the corresponding (S)-configured sulfoxides such as (+)-methiin and (+)-alliin, which are responsible for valuable physiological activities in mammals, and have high stereoselectivity. Herein we have established an effective preparative laboratory scale production method to obtain enantiomerically pure chiral sulfoxides using an IDO biocatalyst. [Copyright &y& Elsevier]

We determined the enzymatic characteristics of an industrially important biocatalyst, a-ketoglutarate-dependent L-isoleucine dioxygenase (IDO), which was found to be the enzyme responsible for the generation of (2S,3R,4S)-4-hydroxyisoleucine in Bacillus thuringiensis 2e2. Depending on the amino acid used as the substrate, IDO catalyzed three different types of oxidation reactions: hydroxylation, dehydrogenation, and sulfoxidation. IDO stereoselectively hydroxylated several hydrophobic aliphatic L-amino acids, as well as L-isoleucine, and produced (S)-3-hydroxy-L-allo-isoleucine, 4-hydroxy-L-leucine, (S)-4-hydroxy-L-norvaline, 4-hydroxy-L-norleucine, and 5-hydroxy-L-norleucine. The IDO reaction product of L-isoleucine, (2S,3R,4S)-4-hydroxyisoleucine, was again reacted with IDO and dehydrogenated into (2S,3R)-2-amino-3-methyl-4-ketopentanoate, which is also a metabolite found in B. thuringiensis 2e2. Interestingly, IDO catalyzed the sulfoxidation of some sulfur-containing L-amino acids and generated L-methionine sulfoxide and L-ethionine sulfoxide. Consequently, the effective production of various modified amino acids would be possible using IDO as the biocatalyst. [ABSTRACT FROM AUTHOR]

The type I alpha/beta interferons (IFN-α/β) are known to play an important role in host defense against influenza A virus infection, but we have now discovered that the recently identified type III IFNs (IFN-λ) constitute the major response to intranasal infection with this virus. Type III IFNs were present at much higher levels than type I IFNs in the lungs of infected mice, and the enhanced susceptibility of STAT2-/- animals demonstrated that only signaling through the IFN-α/β or IFN-λ pathways was sufficient to mediate protection. This finding offers a possible explanation for the similar levels of antiviral protection found in wild-type (WT) mice and in animals lacking a functional type I IFN receptor (IFNAR-/-) but also argues that our current understanding of type III IFN induction is incomplete. While murine IFN-λ production is thought to depend on signaling through the type I IFN receptor, we demonstrate that intranasal influenza A virus infection leads to the robust type III IFN induction in the lungs of both WT and IFNAR-/- mice. This is consistent with previous studies showing that IFNAR-mediated protection is redundant for mucosal influenza virus infection and with data showing that the type III IFN receptor is expressed primarily by epithelial cells. However, the overlapping effects of these two cytokine families are limited by their differential receptor expression, with a requirement for IFN-α/β signaling in combating systemic disease. [ABSTRACT FROM AUTHOR]

Mitochondria are proposed to be a major oxygen sensor in hypoxic pulmonary vasoconstriction (HPV), a unique response of the pulmonary circulation to low oxygen tension. Mitochondrial factors including reactive oxygen species, cytochrome c, ATP, and magnesium are potent modulators of voltage-gated K+ (Kv ) channels in the plasmalemmal membrane of pulmonary arterial (PA) smooth muscle cells (PASMCs). Mitochondria have also been found close to the plasmalemmal membrane in rabbit main PA smooth muscle sections. Therefore, we hypothesized that differences in mitochondria localization in rat PASMCs and systemic mesenteric arterial smooth muscle cells (MASMCs) may contribute to the divergent oxygen sensitivity in the two different circulations. Cellular localization of mitochondria was compared with immunofluorescent labeling, and differences in functional coupling between mitochondria and Kv channels was evaluated with the patch-clamp technique and specific mitochondrial inhibitors antimycin A (acting at complex III of the mitochondrial electron transport chain) and oligomycin A (which inhibits the ATP synthase). It was found that mitochondria were located significantly closer to the plasmalemmal membrane in PASMCs compared with MASMCs. Consistent with these findings, the effects of the mitochondrial inhibitors on Kv current (IKv) were significantly more potent in PASMCs than in MASMCs. The cytoskeletal disruptor cytochalasin B (10 μM) also altered mitochondrial distribution in PASMCs and significantly attenuated the effect of antimycin A on the voltage-dependent parameters of IKv . These findings suggest a greater structural and functional coupling between mitochondria and Kv channels specifically in PASMCs, which could contribute to the regulation of PA excitability in HPV. [ABSTRACT FROM AUTHOR]

Abstract: The Raman spectra of nanostructures formed on silicon Si single-crystalline wafers by implantation with hydrogen ions of fluencies ranging within D∼2×1016–3×1017 cm−2 are reported. The presence of both crystalline and amorphous silicon phases were found in the spectra. A non-monotonic growth in the intensities of the peaks originating from the crystalline and the amorphous phases with a dose of the implantation was registered. A ratio of the intensities of the main peaks of the amorphous to the crystalline Si phases also demonstrated a non-monotonic behaviour (“high-dose effect”). Possible reasons and mechanisms of the non-monotonic dependence of a “degree” of amorphization on a dose of the implantation (or irradiation) are discussed. [Copyright &y& Elsevier]