Detection and characterization of IgG-and sIgA-abzymes capable of hydrolyzing histone H1

Immunoglobulins IgG and sIgA actively hydrolyzing histone H1 have been detected on analyzing proteolytic activity of antibodies isolated by chromatography on Protein A-agarose from blood serum of patients with multiple sclerosis and from colostrum of healthy mothers. These antibodies hydrolyze other histones less actively and virtually failed to cleave lysozyme of chicken egg. By gel filtration at acidic pH and subsequent analysis of protease activity of chromatographic fractions, it was shown that IgG and sIgA molecules were responsible for hydrolysis of histone H1. Anti-histone H1 antibodies of IgG and sIgA classes were purified by affinity chromatography on histone H1-Sepharose from catalytically active antibody preparations. The protease activity of anti-histone H1 IgG antibodies was inhibited by serine proteinase inhibitors, whereas anti-histone H1 sIgA antibodies were insensitive to inhibitors of serine, asparagine, and cysteine proteases.     

Assessing the performance of volunteers in monitoring streams

1. Citizens are concerned about the quality of water resources and many participate in monitoring activities, though doubts remain about the quality of the data volunteers collect. We trained volunteers to collect benthic macroinvertebrates using professional protocols. Of the seven stream sites sampled by volunteer crews, six sites were also sampled by professional crews.
2. In the laboratory, volunteers used morphological features to identify as many different taxa as possible within the major insect orders; their identification was approximately to family. Volunteers calculated five metrics: total taxon richness, richness of three key groups (Ephemeroptera, Plecoptera and Trichoptera), and percentage dominance of the three most abundant taxa. All metrics were strongly correlated with (a) the percentage of urbanized area in the catchment and (b) the metrics derived from a more complete taxonomic identification by a professional scientist. Taxon richness metrics declined with urban development, while percent dominance increased.
3. An overall summary multimetric index was used to compare the field and laboratory procedures of volunteers and professionals. Using an ANOVA model, we detected no significant difference between field samples collected by volunteers and professionals. The variance of index values associated with differences between crews was zero. The ability of the index to detect significant differences among sites (statistical power) improved by only 13% for assessments based on professional laboratory identification instead of volunteer laboratory identification.
4. Citizen volunteers, when properly trained, can collect reliable data and make stream assessments that are comparable to those made by professionals. Data collected by volunteers can supplement information used by government agencies to manage and protect rivers and streams.     

Markov State Models Reveal a Two-Step Mechanism of miRNA Loading into the Human Argonaute Protein: Selective Binding followed by Structural Re-arrangement

Argonaute (Ago) proteins and microRNAs (miRNAs) are central components in RNA interference, which is a key cellular mechanism for sequence-specific gene silencing. Despite intensive studies, molecular mechanisms of how Ago recognizes miRNA remain largely elusive. In this study, we propose a two-step mechanism for this molecular recognition: selective binding followed by structural re-arrangement. Our model is based on the results of a combination of Markov State Models (MSMs), large-scale protein-RNA docking, and molecular dynamics (MD) simulations. Using MSMs, we identify an open state of apo human Ago-2 in fast equilibrium with partially open and closed states. Conformations in this open state are distinguished by their largely exposed binding grooves that can geometrically accommodate miRNA as indicated in our protein-RNA docking studies. miRNA may then selectively bind to these open conformations. Upon the initial binding, the complex may perform further structural re-arrangement as shown in our MD simulations and eventually reach the stable binary complex structure. Our results provide novel insights in Ago-miRNA recognition mechanisms and our methodology holds great potential to be widely applied in the studies of other important molecular recognition systems.     

Sea ice resource selection models for polar bears in the Barents Sea subpopulation

The extent, thickness and age of Arctic sea ice has dramatically declined since the late 1990s, and these trends are predicted to continue. Exploring the habitat use of sea‐ice‐dependent species can help us understand which resources they use and how their distribution responds to a changing environment. The goal of this study was to develop predictive models of the habitat use of an Arctic apex predator. Polar bear Ursus maritimus habitat use in the Barents Sea subpopulation was modelled with seasonal resource selection functions (RSFs) using satellite‐linked telemetry data from 294 collars deployed on female polar bears between 1991 and 2015. Polar bears selected habitat in the Marginal Ice Zone, with a preference for intermediate sea ice concentrations (40–80%). They spent most time in areas with relatively short travel distances to 15 or 75% ice concentration, and during spring and autumn they exhibited a preference for sea ice areas over the continental shelf or over shallower bathymetry). Predictions of the distribution of polar bears in the Barents Sea area can be made for specific sea ice scenarios using these models. Two such predictive distribution maps based on the autumn seasonal model were made and validated against two independent polar bear survey datasets collected in August 2004 and August 2015. The distribution of optimal polar bear habitat has shifted strongly northwards in all seasons of the year during the 25 yr study period.     

Identification of Ca<Superscript>2+</Superscript> signaling components in neural stem/progenitor cells during differentiation into neurons and glia in intact and dissociated zebrafish neurospheres

The development of the CNS in vertebrate embryos involves the generation of different sub-types of neurons and glia in a complex but highly-ordered spatio-temporal manner. Zebrafish are commonly used for exploring the development, plasticity and regeneration of the CNS, and the recent development of reliable protocols for isolating and culturing neural stem/progenitor cells (NSCs/NPCs) from the brain of adult fish now enables the exploration of mechanisms underlying the induction/specification/differentiation of these cells. Here, we refined a protocol to generate proliferating and differentiating neurospheres from the entire brain of adult zebrafish. We demonstrated via RT-qPCR that some isoforms of ip3r, ryr and stim are upregulated/downregulated significantly in differentiating neurospheres, and via immunolabelling that 1,4,5-inositol trisphosphate receptor (IP₃R) type-1 and ryanodine receptor (RyR) type-2 are differentially expressed in cells with neuron- or radial glial-like properties. Furthermore, ATP but not caffeine (IP₃R and RyR agonists, respectively), induced the generation of Ca²⁺ transients in cells exhibiting neuron- or glial-like morphology. These results indicate the differential expression of components of the Ca²⁺-signaling toolkit in proliferating and differentiating cells. Thus, given the complexity of the intact vertebrate brain, neurospheres might be a useful system for exploring neurodegenerative disease diagnosis protocols and drug development using Ca²⁺ signaling as a read-out.     

Competition of As and other Group 15 elements for surface binding sites of an extremophilic Acidomyces acidophilus isolated from a historical tin mining site

An arsenic-resistant fungal strain, designated WKC-1, was isolated from a waste roaster pile in a historical tin mine in Cornwall, UK and successfully identified to be Acidomyces acidophilus using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF MS) proteomic-based biotyping approach. WKC-1 showed considerable resistance to As⁵⁺ and Sb⁵⁺ where the minimal inhibitory concentration (MIC) were 22500 and 100 mg L⁻¹, respectively, on Czapex-Dox Agar (CDA) medium; it was substantially more resistant to As⁵⁺ than the reference strains CBS 335.97 and CCF 4251. In a modified CDA medium containing 0.02 mg L⁻¹ phosphate, WKC-1 was able to remove 70.30% of As⁵⁺ (100 mg L⁻¹). Sorption experiment showed that the maximum capacity of As⁵⁺ uptake was 170.82 mg g⁻¹ dry biomass as predicted by the Langmuir model. The presence of Sb⁵⁺ reduced the As⁵⁺ uptake by nearly 40%. Based on the Fourier-transform infrared spectroscopy (FT-IR) analysis, we propose that Sb is competing with As for these sorption sites: OH, NH, CH, SO₃ and PO₄ on the fungal cell surface. To our knowledge, this is the first report on the impact of other Group 15 elements on the biosorption of As⁵⁺ in Acidomyces acidophilus.

     

A newAstragalus (Fabaceae) from southern Peloponnisos

Astragalus maniaticus (Fabaceae), a new species endemic to the Mani Peninsula in Peloponnisos, southern Greece, is described and illustrated. Its closest affinities are still uncertain but within Greece, it lacks close allies.Dedicated to emer. Univ.-Prof. DrFriedrich Ehrendorfer on the occasion of his 70th birthday     

ACQUISITION OF CHICK CYTOSOL THYMIDINE KINASE ACTIVITY BY THYMIDINE KINASE-DEFICIENT MOUSE FIBROBLAST CELLS AFTER FUSION WITH CHICK ERYTHROCYTES

Chick-mouse heterokaryons were obtained by UV-Sendai virus-induced fusion of chick erythrocytes with thymidine (dT) kinase-deficient mouse fibroblast [LM(TK^-)] cells. Autoradiographic studies demonstrated that 1 day after fusion, [³H]dT was incorporated into both red blood cell and LM(TK^-) nuclei of 23% of the heterokaryons. Self-fused LM(TK^-) cells failed to incorporate [³H]dT into nuclear DNA. 15 clonal lines of chick-mouse somatic cell hybrids [LM(TK^-)/CRB] were isolated from the heterokaryons by cultivating them in selective hypoxanthine-aminopterin-thymidine-glycine medium. LM(TK^-) and chick erythrocytes exhibited little, if any, cytosol dT kinase activity. In contrast, all 15 LM(TK^-)/CRB lines contained levels of cytosol dT kinase activity comparable to that found in chick embryo cells. Disk polyacrylamide gel electrophoresis and isoelectric focusing analyses demonstrated that the LM(TK^-)/CRB cells contained chick cytosol, but not mouse cytosol dT kinase. The LM(TK^-)/CRB cells also contained mouse mitochondrial, but not chick mitochondrial dT kinase. Hence, the clonal lines were somatic cell hybrids and not LM(TK^-) cell revertants. The experiments demonstrate that chick erythrocyte cytosol dT kinase can be activated in heterokaryons and in hybrid cells, most likely as a result of functions supplied by mouse fibroblast cells.