The human spindle assembly checkpoint protein Bub3 is required for the establishment of efficient kinetochore-microtubule attachments

The spindle assembly checkpoint monitors the status of kinetochore-microtubule (K-MT) attachments and delays anaphase onset until full metaphase alignment is achieved. Recently, the role of spindle assembly checkpoint proteins was expanded with the discovery that BubR1 and Bub1 are implicated in the regulation of K-MT attachments. One unsolved question is whether Bub3, known to form cell cycle constitutive complexes with both BubR1 and Bub1, is also required for proper chromosome-to-spindle attachments. Using RNA interference and high-resolution microscopy, we analyzed K-MT interactions in Bub3-depleted cells and compared them to those in Bub1- or BubR1-depleted cells. We found that Bub3 is essential for the establishment of correct K-MT attachments. In contrast to BubR1 depletion, which severely compromises chromosome attachment and alignment, we found Bub3 and Bub1 depletions to produce defective K-MT attachments that, however, still account for significant chromosome congression. After Aurora B inhibition, alignment defects become severer in Bub3- and Bub1-depleted cells, while partially rescued in BubR1-depleted cells, suggesting that Bub3 and Bub1 depletions perturb K-MT attachments distinctly from BubR1. Interestingly, misaligned chromosomes in Bub3- and Bub1-depleted cells were found to be predominantly bound in a side-on configuration. We propose that Bub3 promotes the formation of stable end-on bipolar attachments.     

Retinoid X Receptor Agonists Upregulate Genes Responsible for the Biosynthesis of All-Trans-Retinoic Acid in Human Epidermis

UAB30 is an RXR selective agonist that has been shown to have potential cancer chemopreventive properties. Due to high efficacy and low toxicity, it is currently being evaluated in human Phase I clinical trials by the National Cancer Institute. While UAB30 shows promise as a low toxicity chemopreventive drug, the mechanism of its action is not well understood. In this study, we investigated the effects of UAB30 on gene expression in human organotypic skin raft cultures and mouse epidermis. The results of this study indicate that treatment with UAB30 results in upregulation of genes responsible for the uptake and metabolism of all-trans-retinol to all-trans-retinoic acid (ATRA), the natural agonist of RAR nuclear receptors. Consistent with the increased expression of these genes, the steady-state levels of ATRA are elevated in human skin rafts. In ultraviolet B (UVB) irradiated mouse skin, the expression of ATRA target genes is found to be reduced. A reduced expression of ATRA sensitive genes is also observed in epidermis of mouse models of UVB-induced squamous cell carcinoma and basal cell carcinomas. However, treatment of mouse skin with UAB30 prior to UVB irradiation prevents the UVB-induced decrease in expression of some of the ATRA-responsive genes. Considering its positive effects on ATRA signaling in the epidermis and its low toxicity, UAB30 could be used as a chemoprophylactic agent in the treatment of non-melanoma skin cancer, particularly in organ transplant recipients and other high risk populations.     

Multiscale Investigation of Sodium-Ion Battery Anodes: Analytical Techniques and Applications

The anode/electrolyte interface behavior, and by extension, the overall cell performance of sodium-ion batteries is determined by a complex interaction of processes that occur at all components of the electrochemical cell across a wide range of size- and timescales. Single-scale studies may provide incomplete insights, as they cannot capture the full picture of this complex and intertwined behavior. Broad, multiscale studies are essential to elucidate these processes. Within this perspectives article, several analytical and theoretical techniques are introduced, and described how they can be combined to provide a more complete and comprehensive understanding of sodium-ion battery (SIB) performance throughout its lifetime, with a special focus on the interfaces of hard carbon anodes. These methods target various length- and time scales, ranging from micro to nano, from cell level to atomistic structures, and account for a broad spectrum of physical and (electro)chemical characteristics. Specifically, how mass spectrometric, microscopic, spectroscopic, electrochemical, thermodynamic, and physical methods can be employed to obtain the various types of information required to understand battery behavior will be explored. Ways are then discussed how these methods can be coupled together in order to elucidate the multiscale phenomena at the anode interface and develop a holistic understanding of their relationship to overall sodium-ion battery function.     

γ-Lactam-Based Antifungal Compounds against the Wheat Pathogen Zymoseptoria tritici

As new environmentally friendly and effective antifungal agents are deeply needed, efficient ecofriendly strategies were designed to access two series of compounds inspired from natural γ-lactams. Designed compounds were fully characterized and evaluated as antifungal candidates against Zymoseptoria tritici, the main pathogen on wheat crops. The targeted derivatives were prepared from natural resources using green solvents, simple procedures, and limited purification steps. These bio-inspired compounds revealed as good candidates for further development of efficient crop protection products. Indeed, the HIT compounds exhibited IC₅₀ around 1 μg/mL and were more active than the references tebuconazole and bixafen towards some multidrug-resistant strains. Two dozen of derivatives have been obtained for each series and allowed to establish early structure-activity relationships useful for the development of next generation of γ-lactam derivatives with improved efficacy.     

Characterization of human HtrA2, a novel serine protease involved in the mammalian cellular stress response.

Human HtrA2 is a novel member of the HtrA serine protease family and shows extensive homology to the Escherichia coli HtrA genes that are essential for bacterial survival at high temperatures. HumHtrA2 is also homologous to human HtrA1, also known as L56/HtrA, which is differentially expressed in human osteoarthritic cartilage and after SV40 transformation of human fibroblasts. HumHtrA2 is upregulated in mammalian cells in response to stress induced by both heat shock and tunicamycin treatment. Biochemical characterization of humHtrA2 shows it to be predominantly a nuclear protease which undergoes autoproteolysis. This proteolysis is abolished when the predicted active site serine residue is altered to alanine by site-directed mutagenesis. In human cell lines, it is present as two polypeptides of 38 and 40 kDa. HumHtrA2 cleaves beta-casein with an inhibitor profile similar to that previously described for E. coli HtrA, in addition to an increase in beta-casein turnover when the assay temperature is raised from 37 to 45 degrees C. The biochemical and sequence similarities between humHtrA2 and its bacterial homologues, in conjunction with its nuclear location and upregulation in response to tunicamycin and heat shock suggest that it is involved in mammalian stress response pathways.     

The Implication of Early Chromatin Changes in X Chromosome Inactivation

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Modification of cellulosic fabric using polyvinyl alcohol, part-II: Colorfastness properties

A series of aqueous solutions of poly(vinyl alcohol) of various commercial products were prepared and applied onto the surfaces of cotton and blends of cotton/polyester fabrics. Fourier transform infrared spectrophotometer was used to confirm the molecular structure of the polyvinyl alcohol used. Performance tests such as colorfastness to rubbing (dry and wet) and colorfastness to washing were determined. The controlling variables affecting the performance properties of the finished substrate such as post-treatment with poly(vinyl alcohol) of various commercial trades, concentration and dilutions were studied. Crocking, washing and hue change of the treated dyed and printed fabrics is accompanied by the formation of semi-inter-penetrated network structure due to the presence of the hydroxyl (-OH) groups which make feasible to a number of grafting and physical cross linking reactions of polymer backbone.     

Disruption of tubulin polymerization and cell proliferation by 1-naphthylarsonic acid

Arsenical compounds exhibit a differential toxicity to cancer cells. Microtubules are a primary target of a number of anticancer drugs, such as arsenical compounds. The interaction of 1-NAA (1-naphthylarsonic acid) has been investigated on microtubule polymerization under in vitro and cellular conditions. Microtubules were extracted from sheep brain. Transmission electron microscopy was used to show microtubule structure in the presence of 1-NAA. Computational docking method was applied for the discovery of ligand-binding sites on the microtubular proteins. Proliferation of HeLa cells and HF2 (human foreskin fibroblasts) was measured by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay method following their incubation with 1-NAA. Fluorescence microscopic labelling was done with the help of α-tubulin monoclonal antibody and Tunel kit was used to investigate the apoptotic effects of 1-NAA on the HeLa cells. 1-NAA inhibits the tubulin polymerization by the formation of abnormal polymers having high affinity to the inner cell wall.