Examples of characteristics of wood that affect mould growth: a meta-analysis

Building materials differ in their susceptibility to mould growth. Wood is a material often considered to have a low mould resistance. However, wood is not a homogenous material and different characteristics of the material are expected to have an impact on mould growth. In this paper, it was shown that wood species (pine or spruce), sawing pattern (centre-board or side-board) and surface structure (planed or sawn) affected mould growth. In addition, it was indicated that the susceptibility cannot be described by one single parameter, but also depends on other parameters. It is therefore difficult to estimate the susceptibility of wood in general. These conclusions were drawn from a meta-analysis, using data from five separate, previously performed laboratory studies conducted at 90% relative humidity and 22 °C, and from a laboratory study performed at 95% RH and 22 °C.     

Low micromolar inhibitors of galectin-3 based on 3'-derivatization of N-acetyllactosamine

A strategy for generating potential galectin inhibitors was devised based on derivatization at the C-3' atom in 3'-amino-N-acetyllactosamine by using structural knowledge of the galectin carbohydrate recognition site. A collection of 12 compounds was prepared by N-acylations or N-sulfonylations. Hydrophobic tagging of the O-3 atom in the N-acetylglucosamine residue with a stearic ester allowed rapid and simple product purification. The compounds were screened in a galectin-3 binding assay and three compounds with significantly higher inhibitory activities compared to the parent N-acetyllactosaminide were found. These three best inhibitors all carried an aromatic amide at the C-3' position of the galactose moiety, which indicates that favorable interactions were formed between the aromatic group and galectin-3. The best inhibitor had an IC50 value (4.4 microM) about 50 times better than the parent N-acetyllactosaminide, which implies that it has potential as a valuable tool for studying galectin-3 biological functions and also as a lead compound for the development of galectin-3-blocking pharmaceuticals.     

Electrospinning of cellulose‐based nanofibers

Cellulose derivatives of carboxymethyl cellulose sodium salt (CMC), hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and enzymatically treated cellulose have been electrospun, and the microstructure of the resulting nanofibers has been analyzed by scanning electron microscopy (SEM). Before electrospinning, the solutions were characterized by viscometry and surface tension measurements, and the results were correlated with spinnability. Four different CMC derivatives, varying in molecular weight (M_w), degree of substitution (DS), and substitution pattern, have been electrospun in mixtures with poly(ethylene oxide) (PEO), and nanofibers of various characteristics have formed. The CMC‐based nanostructures, i.e., the nonwoven sheet and individual nanofibers, proved to be independent of M_w and DS but largely dependent on the substitution pattern. The nonwoven sheets varied in homogeneity, and beads appeared on the individual fibers. Depending on the chemical nature of the CMC, the extraction of PEO resulted in pure CMC nanostructures of varying appearance, indicating that the distribution of PEO and CMC in the nanofibers also varied. Two different HPMC derivatives, varying in DS, were electrospun into nanofibers. Homogeneous nonwoven sheets based on nanofibers of similar appearance are formed, independent of the substitution content of the HPMC sample. Preliminary fibers were obtained from enzymatically treated cellulose in a solvent system based on lithium chloride dissolved in dimethyl acetamide (LiCl: DMAc). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1473–1482, 2007     

High-speed tracking of murine cardiac stem cells by harmonic nanodoublers

Potassium niobate nonlinear nanoparticles are used for the first time to monitor the evolution of embryonic stem cells (ESC) by second harmonic microscopy. These particles feature the complete absence of photo-bleaching and unlimited excitation wavelength flexibility. The potential of this approach is made evident for tissue-regeneration studies and applications, by capturing a high-speed movie of ESC-derived cardiomyocytes autonomously beating within a cluster. Time-resolved data are analyzed to retrieve 3D information of the contraction pattern at the cellular level.     

A central core structure in an antibody variable domain determines antigen specificity

Antibody binding sites provide an adaptable surface capableof interacting with essentially any molecular target. UsingCDR shuffling, residues important for the assembly of mucin-1specific paratopes were defined by random recombination of thecomplementarity determining regions derived from a set of mucin-1specific clones, previously selected from an antibody fragmentlibrary. It was found that positions 33 and 50 in the heavychain and 32, 34, 90, 91 and 96 in the light chain were conservedin many of the clones. These particular residues seem to belocated centrally in the binding site as indicated by a structuremodel analysis. The importance of several of these conservedresidues was supported by their presence in a mouse monoclonalantibody with a known structure and the same epitope specificity.Several of these corresponding residues in the mouse monoclonalantibody are known to interact with the antigen. In conclusion,critical residues important for maintaining a human antigen-specificbinding site during the process of in vitro antibody evolutionwere defined. Furthermore, an explanation for the observed restrictedgermline gene usage in certain antibody responses against proteinepitopes is provided.     

An adaptive mutation in adenylate kinase that increases organismal fitness is linked to stability-activity trade-offs

Protein function is a balance between activity and stability. However, the relevance of stability-activity trade-offs for protein evolution and their impact on organismal fitness have been difficult to determine. Previously, we have linked organismal survival at increasing temperatures to adaptive changes to a single protein sequence through allelic replacement of an essential gene, adenylate kinase (adk), in a thermophile. In vivo continuous evolution of the temperature-sensitive thermophile has shown that the first step toward increased organismal fitness is mutation of glutamine-199 to arginine in the mesophilic enzyme (AKsub Q199R). Here, we show that although substitution of Arg-199 did confer a modest increase in stability (0.6 kcal mol(-1)at 20 degrees C; DeltaT(m) = 3.0 degrees C), it is a large change in the activity profile of the enzyme that is responsible for its exceptional robustness during the earlier experimental evolution study. Kinetic studies of AKsub Q199R show that it has a strong loss of enzymatic activity (>50%) at lower temperatures (20-45 degrees C) and a subsequent increase at elevated temperatures. The stability-activity trade-off observed for AKsub Q199R was linked to the rigidification of the overall structure through stabilization of a polypeptide loop containing Arg-199 that is part of the ATP-binding site of the enzyme. Structural analysis revealed the formation of new ionic interactions facilitated by Arg-199. Our results suggest that stability-activity trade-offs are employed readily as an evolutionary strategy during natural selection to increase organismal fitness.     

Expression and regulatory role of receptors for vasoactive intestinal peptide in bone cells

An intense network of nerve fibers can be demonstrated in skeletal tissues, not only in the periosteum but also within cortical bone, growth plate, and bone marrow. This neuro-osteogenic network expresses a restricted number of signalling molecules, including neuropeptides, neurotransmitters, and neurotrophins. Several lines of evidence indicate that receptors for these molecules are present on bone cells and that activation of these receptors leads to changes in bone cell activities. In addition, deletion of signalling molecules has been shown to alter bone metabolism. In the present review, these studies are summarized with a focus on distribution and effects of vasoactive intestinal peptide.     

Self-Reinforced α-SiAlON Ceramics with Improved Damage Tolerance Developed by a New Processing Strategy

Alpha-SiAlON ceramics with a refined self-reinforced microstructure, i.e., containing acicular grains with dimensions much smaller than those obtained in previous studies, embedded in a matrix consisting of submicrometer-sized isotropic grains, were prepared by applying a rapid one-step sintering procedure. To suppress the overabundant formation of α-SiAlON nuclei, a combination of stabilizing cations, Y + Yb, was used; to encourage formation of acicular α-SiAlON grains, a small amount of an extra liquid (∼3 vol%) was introduced; to avoid abnormal grain coarsening resulting from dynamic ripening, the final sintering temperature was set to just slightly above the minimum temperature threshold for activating grain growth (1700°C). The fully dense compacts obtained exhibited excellent thermal-shock resistance, and hardness and fracture toughness values of 20 GPa and 5.1 MPa·m^1/2, respectively.     

A Copper Story: From Protein Folding and Metal Transport to Cancer

Enzymes need to fold into unique three-dimensional structures in order to function. Copper ions are cofactors in many essential enzymes. Such enzymes need to couple polypeptide folding with metal incorporation, as the metal sites are often integrated within the folded structure. Since free copper ions are toxic, most organisms have highly specialized copper transport systems. The human cytoplasmic copper chaperone Atox1 delivers copper to P_1B-type ATPases in the Golgi, for incorporation into copper-dependent enzymes following the secretory path. Copper plays key roles in cancer development, as copper-dependent enzymes are needed for tumor growth and metastasis. In addition, platinum-based drugs are exported out of cells by the copper transport machinery. Recent findings also imply that some copper transport proteins regulate cell growth and development. In this brief journey of my later career, I will discuss the roles of copper in protein folding, mechanisms of copper ion transport, and cisplatin hitchhiking. The identification of new partners for Atox1 underscore the importance of further research in this area for combating cancer.