Stock of standing dead trees in boreal forests of Central Siberia

A significant part of carbon assimilated by forest is deposited in tree trunks. Growth and development of tree stands is accompanied by accumulation of standing dead trees (snags) due to natural tree mortality and as a result of the impact of exogenous factors. Carbon accumulated in these dead trunks is excluded from the fast turnover due to low rate of wood decomposition, so that snags can be considered as a pool of organic carbon with a slow rate of its return to the atmosphere. We estimated stock of snags on 54 sample plots, which represent the main types of forest ecosystems in the northern and middle taiga of Central Siberia. In the middle taiga, stock of snags varied from up to 7 m3 ha-1 in Siberian spruce forests to 20-42 m3 ha-1 in Scots pine forests. Larch forests in the northern taiga had the similar stock of snags as larch forests in the middle taiga despite significantly higher growing stock in the later. Snags contributed from 4 to 19% to the total stock of woody biomass in studied forests. This study indicated the significance of snags and can be used to estimate carbon budget of forest ecosystems of the region

mRNA expression profile of mouse oligodendrocytes in inflammatory conditions

© 2016, Pleiades Publishing, Ltd.In this study, we performed transcriptome profiling of oligodendrocyte culture of mice treated with the remyelinating therapeutic agent benztropine in the presence and absence of interferon gamma (IFNγ). The results of this work are important for understanding the expression profile of oligodendrocytes under conditions of systemic inflammation in the central nervous system in multiple sclerosis as well as the mechanisms of cellular response to benztropine in light of its possible use for the treatment of multiple sclerosis

Evolution of inhibitor-resistant natural mutant forms of HIV-1 protease probed by pre-steady state kinetic analysis

© 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM) Pre-steady state kinetic analysis of mechanistic features of substrate binding and processing is crucial for insight into the evolution of inhibitor-resistant forms of HIV-1 protease. These data may provide a correct vector for rational drug design assuming possible intrinsic dynamic effects. These data should also give some clues to the molecular mechanism of protease action and resistance to inhibitors. Here we report pre-steady state kinetics of the interaction of wild type or mutant forms of HIV-1 protease with a FRET-labeled peptide. The three-stage “minimal” kinetic scheme with first and second reversible steps of substrate binding and with following irreversible peptide cleavage step adequately described experimental data. For the first time, a set of “elementary” kinetic parameters of wild type HIV-1 protease and its natural mutant inhibitor-resistant forms MDR-HM, ANAM-11 and prDRV4 were compared. Inhibitors of the first and second generation were used to estimate the inhibitory effects on HIV-1 protease activity. The resulting set of kinetic data supported that the mutant forms are kinetically unaffected by inhibitors of the first generation, proving their functional resistance to these compounds. The second generation inhibitor darunavir inhibited mutant forms MDR-HM and ANAM-11, but was ineffective against prDRV4. Our kinetic data revealed that these inhibitors induced different conformational changes in the enzyme and, thereby they have different mode of binding in the enzyme active site. These data confirmed hypothesis that the driving force of the inhibitor-resistance evolution is disruption of enzyme-inhibitor complex by changing of the contact network in the inhibitor binding site

Development of a recombinant immunotoxin for the immunotherapy of autoreactive lymphocytes expressing MOG-specific BCRs

© 2016, Springer Science+Business Media Dordrecht.Objective: Myelin oligodendrocyte glycoprotein (MOG) is one of the major autoantigens in multiple sclerosis (MS), therefore selective depletion of autoreactive lymphocytes exposing MOG-specific B cell receptors (BCRs) would be beneficial in terms of MS treatment. Results: Using E. coli we generated an efficient protocol for the purification of the recombinant immunotoxin DT-MOG composed of the extracellular Ig-like domain of MOG fused in frame with the catalytic and translocation subunits of diphtheria toxin (DT, Corynebacterium diphtheriae) under native conditions with a final yield of 1.5 mg per liter of culture medium. Recombinant DT-MOG was recognized in vitro by MOG-reactive antibodies and has catalytic activity comparable with wild-type DT. Conclusion: Enhanced pharmacokinetics (mean residence time in the bloodstream of 61 min) and minimized diminished nonspecific toxicity (LD50 = 1.76 mg/kg) of the DT-MOG makes it a potential candidate for the immunotherapy of MS

Influence of the atrio-ventricular delay optimization on the intra left ventricular delay in cardiac resynchronization therapy

BACKGROUND: Cardiac Resynchronization Therapy (CRT) leads to a reduction of left-ventricular dyssynchrony and an acute and sustained hemodynamic improvement in patients with chronic heart failure. Furthermore, an optimized AV-delay leads to an improved myocardial performance in pacemaker patients. The focus of this study is to investigate the acute effect of an optimized AV-delay on parameters of dyssynchrony in CRT patients. METHOD: 11 chronic heart failure patients with CRT who were on stable medication were included in this study. The optimal AV-delay was defined according to the method of Ismer (mitral inflow and trans-oesophageal lead). Dyssynchrony was assessed echocardiographically at three different settings: AVD(OPT); AVD(OPT)-50 ms and AVD(OPT)+50 ms. Echocardiographic assessment included 2D- and M-mode echo for the assessment of volumes and hemodynamic parameters (CI, SV) and LVEF and tissue Doppler echo (strain, strain rate, Tissue Synchronisation Imaging (TSI) and myocardial velocities in the basal segments) RESULTS: The AVD(OPT )in the VDD mode (atrially triggered) was 105.5 ± 38.1 ms and the AVD(OPT )in the DDD mode (atrially paced) was 186.9 ± 52.9 ms. Intra-individually, the highest LVEF was measured at AVD(OPT). The LVEF at AVD(OPT )was significantly higher than in the AVD(OPT-50)setting (p = 0.03). However, none of the parameters of dyssynchrony changed significantly in the three settings. CONCLUSION: An optimized AV delay in CRT patients acutely leads to an improved systolic left ventricular ejection fraction without improving dyssynchrony

Development of a recombinant immunotoxin for the immunotherapy of autoreactive lymphocytes expressing MOG-specific BCRs

© 2016 Springer Science+Business Media DordrechtObjective: Myelin oligodendrocyte glycoprotein (MOG) is one of the major autoantigens in multiple sclerosis (MS), therefore selective depletion of autoreactive lymphocytes exposing MOG-specific B cell receptors (BCRs) would be beneficial in terms of MS treatment. Results: Using E. coli we generated an efficient protocol for the purification of the recombinant immunotoxin DT-MOG composed of the extracellular Ig-like domain of MOG fused in frame with the catalytic and translocation subunits of diphtheria toxin (DT, Corynebacterium diphtheriae) under native conditions with a final yield of 1.5 mg per liter of culture medium. Recombinant DT-MOG was recognized in vitro by MOG-reactive antibodies and has catalytic activity comparable with wild-type DT. Conclusion: Enhanced pharmacokinetics (mean residence time in the bloodstream of 61 min) and minimized diminished nonspecific toxicity (LD50 = 1.76 mg/kg) of the DT-MOG makes it a potential candidate for the immunotherapy of MS

Development of a recombinant immunotoxin for the immunotherapy of autoreactive lymphocytes expressing MOG-specific BCRs

OBJECTIVE: Myelin oligodendrocyte glycoprotein (MOG) is one of the major autoantigens in multiple sclerosis (MS), therefore selective depletion of autoreactive lymphocytes exposing MOG-specific B cell receptors (BCRs) would be beneficial in terms of MS treatment.RESULTS: Using E. coli we generated an efficient protocol for the purification of the recombinant immunotoxin DT-MOG composed of the extracellular Ig-like domain of MOG fused in frame with the catalytic and translocation subunits of diphtheria toxin (DT, Corynebacterium diphtheriae) under native conditions with a final yield of 1.5 mg per liter of culture medium. Recombinant DT-MOG was recognized in vitro by MOG-reactive antibodies and has catalytic activity comparable with wild-type DT.CONCLUSION: Enhanced pharmacokinetics (mean residence time in the bloodstream of 61 min) and minimized diminished nonspecific toxicity (LD50 = 1.76 mg/kg) of the DT-MOG makes it a potential candidate for the immunotherapy of MS

A novel expression cassette delivers efficient production of exclusively tetrameric human butyrylcholinesterase with improved pharmacokinetics for protection against organophosphate poisoning

© 2015 Published by Elsevier B.V. Butyrylcholinesterase is a stoichiometric bioscavenger against poisoning by organophosphorus pesticides and nerve agents. The low level of expression and extremely rapid clearance of monomeric recombinant human butyrylcholinesterase (rhBChE) from bloodstream (t1/2;≈2 min) limits its pharmaceutical application. Recently (Ilyushin at al., PNAS, 2013) we described a long-acting polysialylated recombinant butyrylcholinesterase (rhBChE-CAO), stable in the bloodstream, that protects mice against 4.2 LD50 of VR. Here we report a set of modifications of the initial rhBChE expression vector to improve stability of the enzyme in the bloodstream and increase its production in CHO cells by introducing in the expression cassette: (i) the sequence of the natural human PRAD-peptide in frame with rhBChE gene via "self-processing" viral F2A peptide under control of an hEF/HTLV promoter, and (ii) previously predicted in silico MAR 1-68 and MAR X-29 sequences. This provides fully tetrameric rhBChE (4rhBChE) at 70 mg/l, that displays improved pharmacokinetics (t1/2; = 32 ± 1.2 h, MRT = 43 ± 2 h). 3D Fluorescent visualization and distribution of 125I-labeled enzyme reveals similar low level 4rhBChE and rhBChE-CAO accumulation in muscle, fat, and brain. Administered 4rhBChE was mainly catabolized in the liver and breakdown products were excreted in kidney. Injection of 1.2 LD50 and 1.1 LD50 of paraoxon to BALB/c and knockout BChE-/- mice pre-treated with 4rhBChE (50 mg/kg) resulted in 100% and 78% survival, respectively, without perturbation of long-term behavior. In contrast, 100% mortality of non-pre-treated mice was observed. The high expression level of 4rhBChE in CHO cells permits consideration of this new expression system for manufacturing BChE as a biopharmaceutical

Continuous Flow Reactor for the Production of Stable Amyloid Protein Oligomers

The predominant working hypothesis of Alzheimer's disease is that the proximate pathologic agents are oligomers of the amyloid β-protein (Aβ). "Oligomer" is an ill-defined term. Many different types of oligomers have been reported, and they often exist in rapid equilibrium with monomers and higher-order assemblies. This has made formal structure-activity determinations difficult. Recently, Ono et al. [Ono, K., et al. (2009) Proc. Natl. Acad. Sci. U.S.A. 106, 14745-14750] used rapid, zero-length, in situ chemical cross-linking to stabilize the oligomer state, allowing the isolation and study of pure populations of oligomers of a specific order (number of Aβ monomers per assembly). This approach was successful but highly laborious and time-consuming, precluding general application of the method. To overcome these difficulties, we developed a "continuous flow reactor" with the ability to produce theoretically unlimited quantities of chemically stabilized Aβ oligomers. We show, in addition to its utility for Aβ, that this method can be applied to a wide range of other amyloid-forming proteins

Moose and snowshoe hare competition and a mechanistic explanation from foraging theory

Moose ( Alces alces ) and snowshoe hare ( Lepus americanus ) appear to compete with each other. This was determined using the “natural experiments” of populations found in sympatry and allopatry on islands at Isle Royale National Park, Michigan, and manipulated exclosures. The population densities from these areas are fit to a series of competition models based upon different competitive mechanisms (Schoener 1974a), using non-linear regression techniques. A model of competition for food where the food can be separated into exclusively used and shared categories is found to predict observed densities of moose and hare best. Finally, the competition model's parameters (fraction of food shared and competition coefficients) are shown to agree with values predicted independently from a foraging model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47750/1/442_2004_Article_BF00396753.pd