The neuronal p35 activator of Cdk5 is a novel F-actin binding and bundling protein

The neuronal Cdk5 activator p35 is involved in a multitude of neuronal activities, including cytoskeletal organization. We show here that p35 directly interacts with filamentous actin (F-actin) but not with monomeric actin (G-actin). Through binding, p35 induces the formation of actin bundles and stabilizes F-actin against dilution-induced depolymerization. p35 forms intermolecular self-associations, suggesting that p35 cross-links actin filaments into bundles via its intermolecular self-association. p35 dimerization and association with F-actin occur at the N-terminal region that is absent in the calpain-cleaved product p25, indicating that such p35 properties are lost by its truncation induced under neurotoxic conditions. Using p35 phosphorylated by Cdk5 and a mutational approach, we demonstrate that the phosphorylation of p35 promotes its homodimerization and p35-induced formation of F-actin bundles. In addition, the phosphorylation regulates p35 distribution to microtubule and actin cytoskeletons. Together, these observations define a novel function for p35 in cytoskeletal regulation.     

Synthesis and structural characterization of lanthanide coordination polymers constructed from a 13-membered macrocycle

The lanthanide coordination polymers bearing a 13-membered macrocycle, [(13-EDTA-pnOH)H2] were synthesized. The products [Ln(13-EDTA-pnOH)(H2O)2·NO3]n (Ln = Eu(1), Tb(2), Dy(3)) have been obtained by MS, IR and element analyses. The solid-state structure of 1 was established by single-crystal X-ray analysis. The coordination geometry around the central metal atom in complex 1 is a nine-coor-dinated, tricapped-trigonal prism having six donor atoms (two amine nitrogen atoms, two amide oxygen atoms and two carboxymethyl oxygen atoms) from one ligand, one oxygen atom from a neighboring ligand, and two more oxygen atoms from two water molecules. The europium atoms are linked by―Eu―O―C―O―Eu―bridges to form an infinite chain.     

SELDI-TOF-MS in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease(COPD) has a profound impact on daily life,yet remains underdiagnosed and undertreated.This study aims to discover potential protein biomarkers for diagnosis and classification of COPD.Fifty-seven COPD patients and 40 controls were divided into a training set(30 COPD patients,20 healthy controls) and a test set(27 COPD patients,20 healthy controls).Serum proteomic profiles were measured using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry(SELDI-TOF-MS).A classification tree was established using Biomarker Pattern Software(BPS).Next we screened distinct proteins present in patients with acute exacerbations of COPD(AECOPD),stable COPD and healthy controls,in order to establish diagnostic models for classification of COPD.Twenty peaks showed statistically significant differences between COPD patients and healthy controls(P < 0.05).Two proteomic peaks(3167 and 5477 m/z) were chosen by BPS to establish a classification tree in the training set.The sensitivity and specificity of this classification tree were 92.59% and 90.00% respectively in the testing set.Furthermore,differently expressed proteins were detected among the patients with AECOPD,stable COPD,and healthy controls.Two protein profiles(3167 and 4645 m/z) could distinguish between stable COPD patients and healthy controls.Three protein profiles(3167,2963 and 2973 m/z) could distinguish between AECOPD patients and healthy controls.Three protein profiles(5476,14039 and 2831 m/z) could distinguish between stable COPD patients and AECOPD patients.SELDI-TOFMS Proteinchip technology is a quick,easy and practical,high throughput analytic method.It shows the diagnostic models established by distinguished proteomic peaks can discriminate COPD patients from healthy control and can identify different stages of COPD.It will provide a highly accurate approach for diagnosis and clinical staging of COPD.     

SAP-controlled T-B cell interactions underlie germinal centre formation

Generation of long-term antibody-mediated immunity depends on the germinal centre reaction, which requires cooperation between antigen-specific T and B lymphocytes. In human X-linked lymphoproliferative disease and its gene-targeted mouse model, loss-of-function mutations in signalling lymphocyte activation molecule-associated protein (SAP, encoded by SH2D1a) cause a profound defect in germinal centre formation by an as yet unknown mechanism. Here, using two-photon intravital imaging, we show that SAP deficiency selectively impairs the ability of CD4(+) T cells to stably interact with cognate B cells but not antigen-presenting dendritic cells. This selective defect results in a failure of antigen-specific B cells to receive adequate levels of contact-dependent T-cell help to expand normally, despite Sap(-/-) T cells exhibiting the known characteristics of otherwise competent helper T cells. Furthermore, the lack of stable interactions with B cells renders Sap(-/-) T cells unable to be efficiently recruited to and retained in a nascent germinal centre to sustain the germinal centre reaction. These results offer an explanation for the germinal centre defect due to SAP deficiency and provide new insights into the bi-directional communication between cognate T and B cells in vivo.     

Construction of a BAC library from cucumber (Cucumis sativus L.) and identification of linkage group specific clones

A bacterial artificial chromosome (BAC) library consisting of 19,200 clones with an average insert size of 105 kb has been constructed from a cucumber (Cucumis sativus L.) inbred line S94; derived from a cultivar in North China. The entire library was equivalent to approximately 5 haploid cucumber genomes. To facilitate chromosome engineering and anchor the cucumber genetic linkage map to its chromosomes, 15 sequence-characterized amplified regions (SCAR) and seven simple sequence repeats (SSR) markers from each linkage group of cucumber were used to screen an ordered array of pooled BAC DNA with polymerase chain reaction (PCR). Fifteen markers gave at least two positive clones. As a result, 32 BAC clones representing 7 linkage groups of cucumber were identified, which further validated the genome coverage and utility of the library. This BAC library and linkage group specific clones provide essential resources for future research of the cucumber genome.     

Plant communities: ecosystem stability in Inner Mongolia

Bai et al. suggest that in China's Inner Mongolia steppe, community-level stability arises from compensatory effects among the principal components at both the species and plant functional group (PFG) levels. By analysing a consistent 19-year data set (1980-98), we show here that their analysis of a 24-year field data set (1980-2003) is called into question by inconsistencies in sampling location and numbers after 1998; the authors' findings are further undermined because they do not distinguish temporal variation from spatial heterogeneity in analysing compensatory effects among species or PFGs. We believe that rigorous reanalysis is needed for a better understanding of grassland stability.     

Facile ball-milled synthesis of SnS2-carbon nanocomposites with superior lithium storage

A facile high-energy ball-milling method was developed to synthesize SnS_2-carbon(SnS_2/C-x(x = 40, 50, 60 wt%)) nanocomposites. The results showed that as anode materials for lithium-ion batteries(LIBs), the SnS_2-C nanocomposites exhibited high discharge capacity and excellent cycling stability. For the optimized SnS_2/C-50 wt% nanocomposite, a discharge capacity as high as 700 mA h g~(-1) and the initial coulombic efficiency of 80.8% were achieved at a current density of 100 mA g~(-1). The unique structure with SnS_2 nanoparticles(NPs)embedded into carbon network provided abundant Li-ion storage sites, high electronic conductivity and fast ion diffusion. The ball-milled synthesis is applicable for large-scale preparation of new sulfide-based anode materials with good performance for LIBs.     

Ga-In liquid metal nanoparticles prepared by physical vapor deposition

Controlled synthesis and appropriate characterization of nanoscale particles of gallium-based liquid metals are critical to fulfilling their broad range of applications in the field of flexible, stretchable, and printable micro-/nanoelectronics. Herein, we report a new way to synthesize surfactant-free gallium-indium nanoparticles with controlled particle size on a variety of substrates through a facile physical vapor deposition method. It was found that with prolonged deposition time the liquid metal nanoparticles gradually grew from near-monodispersed small particles with a diameter of ～25 nm to bimodal distributed particles. A nucleation, growth, ripening and merging process was proposed to explain the observed evolution of particle size. Atomic force microscopy measurement indicates that the fabricated liquid metal nanoparticles demonstrate elastic deformation with a certain range of loads and the scanned particle size is dependent on the applied loads. We further investigated the gradual breaking process of the core-shell structured liquid metal nanoparticles, which was evidenced by multiple kinks on the force-separation curve. This work presents a new bottom-up approach to prepare nanoscale liquid metal particles and demonstrates that atomic force microscopy is a suitable technique to characterize the synthesized liquid metal nanoparticles.     

A method for recovery of iron,titanium, and vanadium from vanadium-bearing titanomagnetite

An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures:low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200℃, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.