Dysmyelinating and demyelinating Charcot–Marie–Tooth disease associated with two myelin protein zero gene mutations

Mutations in the myelin protein zero (MPZ) gene are the third most frequent cause of hereditary motor and sensory neuropathies (HMSN), also called Charcot–Marie–Tooth disorders (CMT). Only in case of recurrent mutations occurring in the MPZ gene is it possible to draw phenotype–genotype correlations essential for establishing the prognosis and outcomes of CMT1. We have surveyed a cohort of 67 Polish patients from CMT families with demyelinating neuropathy for mutations in the MPZ gene. In this study, we report two CMT families in which the Ile135Thr and Pro132Leu mutations have been identified for the MPZ gene. These MPZ gene mutations had not been identified hitherto in the Polish population. The Pro132Leu mutation segregates with a severe early-onset dysmyelinating–hypomyelinating neuropathy, whereas the Ile135Thr substitution is associated with the classical phenotype of CMT1. To the best of our knowledge, we present here, for the first time, morphological data obtained in two sural nerve biopsies pointing to a hypomyelination–dysmyelination process in a family harboring the Pro132Leu mutation in the MPZ gene.     

CRHSP-24 phosphorylation is regulated by multiple signaling pathways in pancreatic acinar cells

Ca2+-regulated heat-stable protein of 24 kDa (CRHSP-24) is a serine phosphoprotein originally identified as a physiological substrate for the Ca2+-calmodulin regulated protein phosphatase calcineurin (PP2B). CRHSP-24 is a paralog of the brain-specific mRNA-binding protein PIPPin and was recently shown to interact with the STYX/dead phosphatase protein in developing spermatids (Wishart MJ and Dixon JE. Proc Natl Acad Sci USA 99: 2112-2117, 2002). Investigation of the effects of phorbol ester (12-o-tetradecanoylphorbol-13-acetate; TPA) and cAMP analogs in 32P-labeled pancreatic acini revealed that these agents acutely dephosphorylated CRHSP-24 by a Ca2+-independent mechanism. Indeed, cAMP- and TPA-mediated dephosphorylation of CRHSP-24 was fully inhibited by the PP1/PP2A inhibitor calyculin A, indicating that the protein is regulated by an additional phosphatase other than PP2B. Supporting this, CRHSP-24 dephosphorylation in response to the Ca2+-mobilizing hormone cholecystokinin was differentially inhibited by calyculin A and the PP2B-selective inhibitor cyclosporin A. Stimulation of acini with secretin, a secretagogue that signals through the cAMP pathway in acini, induced CRHSP-24 dephosphorylation in a concentration-dependent manner. Isoelectric focusing and immunoblotting indicated that elevated cellular Ca2+ dephosphorylated CRHSP-24 on at least three serine sites, whereas cAMP and TPA partially dephosphorylated the protein on at least two sites. The cAMP-mediated dephosphorylation of CRHSP-24 was inhibited by low concentrations of okadaic acid (10 nM) and fostriecin (1 microM), suggesting that CRHSP-24 is regulated by PP2A or PP4. Collectively, these data indicate that CRHSP-24 is regulated by diverse and physiologically relevant signaling pathways in acinar cells, including Ca2+, cAMP, and diacylglycerol.     

Characterization of a cysteine protease from wheat Triticum aestivum (cv. Giza 164)

Enzymes, especially proteases, have become an important and indispensable part of the processes used by the modern food and feed industry to produce a large and diversified range of products for human and animal consumption. A cysteine protease, used extensively in the food industry, was purified from germinated wheat Triticum aestivum (cv. Giza 164) grains through a simple reproducible method consisting of extraction, ion exchange chromatography and gel filtration. The molecular weight of the enzyme was estimated to be 61000+/-1200-62000+/-1500 by SDS-PAGE and gel filtration. The cysteine protease had an isoelectric point and pH optimum at 4.4 and 4.0, respectively. The enzyme exhibited more activity toward azocasein than the other examined substrates with K(m) 2.8+/-0.15 mg azocasein/ml. In addition, it had a temperature optimum of 50 degrees C and based on a heat stability study 55% of its initial activity remained after preincubation of the enzyme at 50 degrees C for 30 min prior to substrate addition. All the examined metal cations inhibited the enzyme except Co(2+), Mg(2+), Mn(2+) and Li(+). The proteolytic activity of the enzyme was inhibited by thiol-specific inhibitors, whereas iodoacetate and p-hydroxymercuribenzoate caused a competitive inhibition with Ki values 6+/-0.3 mM and 21+/-1.2 microM, respectively. Soybean trypsin inhibitor had no effect on the enzyme. The enzyme activity remained almost constant for 150 days of storage at -20 degrees C. The properties of this enzyme, temperature and pH optima, substrate specificity, stability and sensitivity to inhibitors or activators, meet the prerequisites needed for food industries.     

Climate–ecosystem modelling made easy: The Land Sites Platform

Dynamic Global Vegetation Models (DGVMs) provide a state-of-the-art process-based approach to study the complex interplay between vegetation and its physical environment. For example, they help to predict how terrestrial plants interact with climate, soils, disturbance and competition for resources. We argue that there is untapped potential for the use of DGVMs in ecological and ecophysiological research. One fundamental barrier to realize this potential is that many researchers with relevant expertize (ecology, plant physiology, soil science, etc.) lack access to the technical resources or awareness of the research potential of DGVMs. Here we present the Land Sites Platform (LSP): new software that facilitates single-site simulations with the Functionally Assembled Terrestrial Ecosystem Simulator, an advanced DGVM coupled with the Community Land Model. The LSP includes a Graphical User Interface and an Application Programming Interface, which improve the user experience and lower the technical thresholds for installing these model architectures and setting up model experiments. The software is distributed via version-controlled containers; researchers and students can run simulations directly on their personal computers or servers, with relatively low hardware requirements, and on different operating systems. Version 1.0 of the LSP supports site-level simulations. We provide input data for 20 established geo-ecological observation sites in Norway and workflows to add generic sites from public global datasets. The LSP makes standard model experiments with default data easily achievable (e.g., for educational or introductory purposes) while retaining flexibility for more advanced scientific uses. We further provide tools to visualize the model input and output, including simple examples to relate predictions to local observations. The LSP improves access to land surface and DGVM modelling as a building block of community cyberinfrastructure that may inspire new avenues for mechanistic ecosystem research across disciplines.     

Prion protein inhibits microtubule assembly by inducing tubulin oligomerization

A growing body of evidence points to an association of prion protein (PrP) with microtubular cytoskeleton. Recently, direct binding of PrP to tubulin has also been found. In this work, using standard light scattering measurements, sedimentation experiments, and electron microscopy, we show for the first time the effect of a direct interaction between these proteins on tubulin polymerization. We demonstrate that full-length recombinant PrP induces a rapid increase in the turbidity of tubulin diluted below the critical concentration for microtubule assembly. This effect requires magnesium ions and is weakened by NaCl. Moreover, the PrP-induced light scattering structures of tubulin are cold-stable. In preparations of diluted tubulin incubated with PrP, electron microscopy revealed the presence of approximately 50 nm disc-shaped structures not reported so far. These unique tubulin oligomers may form large aggregates. The effect of PrP is more pronounced under the conditions promoting microtubule formation. In these tubulin samples, PrP induces formation of the above oligomers associated with short protofilaments and sheets of protofilaments into aggregates. Noticeably, this is accompanied by a significant reduction of the number and length of microtubules. Hence, we postulate that prion protein may act as an inhibitor of microtubule assembly by inducing formation of stable tubulin oligomers.     

Structural Brain Changes after Traditional and Robot-Assisted Multi-Domain Cognitive Training in Community-Dwelling Healthy Elderly

The purpose of this study was to investigate if multi-domain cognitive training, especially robot-assisted training, alters cortical thickness in the brains of elderly participants. A controlled trial was conducted with 85 volunteers without cognitive impairment who were 60 years old or older. Participants were first randomized into two groups. One group consisted of 48 participants who would receive cognitive training and 37 who would not receive training. The cognitive training group was randomly divided into two groups, 24 who received traditional cognitive training and 24 who received robot-assisted cognitive training. The training for both groups consisted of daily 90-min-session, five days a week for a total of 12 weeks. The primary outcome was the changes in cortical thickness. When compared to the control group, both groups who underwent cognitive training demonstrated attenuation of age related cortical thinning in the frontotemporal association cortices. When the robot and the traditional interventions were directly compared, the robot group showed less cortical thinning in the anterior cingulate cortices. Our results suggest that cognitive training can mitigate age-associated structural brain changes in the elderly.

Trial Registration

ClnicalTrials.gov NCT01596205     

Transgenic Mice Expressing Human Immunodeficiency Virus Type 1 in Immune Cells Develop a Severe AIDS-Like Disease

We have constructed transgenic (Tg) mice expressing the entire human immunodeficiency virus type 1 (HIV-1) coding sequences in cells targeted by HIV-1 infection in humans. These Tg mice developed a severe AIDS-like disease leading to early death (<1 month). They developed muscle wasting, severe atrophy and fibrosis of lymphoid organs, tubulointerstitial nephritis, and lymphoid interstitial pneumonitis. In addition the expression of RANTES was increased in various tissues of these Tg mice relative to that in the normal controls. Disease appearance was correlated with the levels of transgene expression. The numerous pathologies observed in these mice are remarkably similar to those observed in human AIDS and, more specifically, in pediatric AIDS.