Search

Integration of plasma and pulsed light or ultraviolet has been investigated for microbial decontamination of foods. However, no studies have reported the microbial disinfection of particulate food using a large-scale system integrating the treatments. In the present study, a large-scale plasma jet-pulsed light-ultraviolet (UV)-C (PPU) system has been developed for the microbial decontamination of particulate foods. The effects of PPU treatment on the inactivation of natural mesophilic aerobic bacteria and yeast and molds of rice germ and the quality properties of rice germ were evaluated at various operation times (3, 5, 7, and 10 min) and sample amount (200, 500, 1,000, and 3,000 g). The efficacy of microbial inactivation of PPU treatment was enhanced with increasing treatment time and decreasing sample amount, and the maximum reduction was observed at 7 min with 200 g samples. The number of the natural bacteria and yeast and mold was reduced to 1.0 and 2.0 log CFU/g from an initial number of 5.7 and 3.7 log CFU/g, respectively. Compared to the individual treatments by atmospheric pressure plasma jet (APPJ) and intense pulsed light (IPL), PPU treatment synergistically inactivated microorganisms while not altering the color, antioxidant activity, or sensory properties of rice germ. The results of this study suggest the potential use of the large-scale PPU treatment system for the microbial decontamination of rice germ while minimizing alterations in quality.

Structures of monothiol and dithiol glutaredoxin-1 from C. oremlandii are reported. Monothiol glutaredoxin-1 formed domain-swapped structures, one of which was in a hetero-oligomer complex., Protein dimerization or oligomerization resulting from swapping part of the protein between neighboring polypeptide chains is known to play a key role in the regulation of protein function and in the formation of protein aggregates. Glutaredoxin-1 from Clostridium oremlandii (cGrx1) was used as a model to explore the formation of multiple domain-swapped conformations, which were made possible by modulating several hinge-loop residues that can form a pivot for domain swapping. Specifically, two alternative domain-swapped structures were generated and analyzed using nuclear magnetic resonance (NMR), X-ray crystallography, circular-dichroism spectroscopy and hydrogen/deuterium-exchange (HDX) mass spectrometry. The first domain-swapped structure (β3-swap) was formed by the hexameric cGrx1–cMsrA complex. The second domain-swapped structure (β1-swap) was formed by monothiol cGrx1 (C16S) alone. In summary, the first domain-swapped structure of an oxidoreductase in a hetero-oligomeric complex is presented. In particular, a single point mutation of a key cysteine residue to serine led to the formation of an intramolecular disulfide bond, as opposed to an intermolecular disulfide bond, and resulted in modulation of the underlying free-energy landscape of protein oligomerization.

The silicon surface texture significantly affects the current density and efficiency of perovskite/silicon tandem solar cells. However, only a few studies have explored fabricating perovskite on textured silicon and the effect of texture on perovskite films because of the limitations of solution processes. Here we produce conformal perovskite on textured silicon with a dry two-step conversion process that incorporates lead oxide sputtering and direct contact with methyl ammonium iodide. To separately analyze the influence of each texture structure on perovskite films, patterned texture, high-resolution photoluminescence (μ-PL), and light beam-induced current (μ-LBIC), 3D mapping is used. This work elucidates conformal perovskite on textured surfaces and shows the effects of textured silicon on the perovskite layers with high-resolution 3D mapping. This approach can potentially be applied to any type of layer on any type of substrate. The efficiency of perovskite/silicon tandem solar cells is affected by silicon surface texture, however fabrication processes in solution limit surface studies. Here a perovskite layer on textured silicon is formed through a dry two-step conversion process with lead oxide sputtering and direct contact with methyl ammonium iodide.

Radio frequency (RF) magnetron-sputtered TiO2 (RS-TiO2) is investigated as a hole-blocking layer for perovskite solar cells. RS-TiO2 shows conformal, dense, and efficiently electron transferable pr...

This paper investigates the correlation between the random lasing properties of organic waveguides made by poly-(9-9dioctylfluorene) (PFO) thin films and the morphology of wrinkled corrugated substrates. The capability to individually control the wrinkle wavelength, shape, and height allows us to separately investigate their role on the sample emission properties. We demonstrate that the main parameter determining the presence of coherent random lasing is the substrate roughness and that, contrary to what could be qualitatively expected, as the roughness increases, coherent random lasing is progressively reduced. Coherent random lasing is observed only for a substrate roughness below 33 nm, while higher roughness leads to amplified spontaneous emission (up to 70 nm) or to the absence of light amplification in the film (above 70 nm). We demonstrate that this result is due to a progressive reduction of the light amplification efficiency in the PFO film, evidencing that coherent random lasing can be obtained only with a right interplay between light amplification and scattering. Besides clarifying the basic aspects of random lasing in organic waveguides, our work opens the way to the realization of organic random lasers with predictable emission properties, thanks to the high control level of the scattering properties of the wrinkled corrugated surfaces.

Indoleamine 2,3-dioxygenase 1 (IDO1), a tryptophan catabolising enzyme, is known as a tumour cell survival factor that causes immune escape in several types of cancer. Flavonoids of Sophora flavescens have a variety of biological benefits for humans; however, cancer immunotherapy effect has not been fully investigated. The flavonoids (1–6) isolated from S. flavescens showed IDO1 inhibitory activities (IC50 4.3–31.4 µM). The representative flavonoids (4–6) of S. flavescens were determined to be non-competitive inhibitors of IDO1 by kinetic analyses. Their binding affinity to IDO1 was confirmed using thermal stability and surface plasmon resonance (SPR) assays. The molecular docking analysis and mutagenesis assay revealed the structural details of the interactions between the flavonoids (1–6) and IDO1. These results suggest that the flavonoids (1–6) of S. flavescens, especially kushenol E (6), as IDO1 inhibitors might be useful in the development of immunotherapeutic agents against cancers.

There is increasing demand for essential fatty acids (EFAs) from non-fish sources such as microalgae, which are considered a renewable and sustainable biomass. The open raceway system (ORS) is an affordable system for microalgae biomass cultivation for industrial applications. However, seasonal variations in weather can affect biomass productivity and the quality of microalgal biomass. The aim of this study was to determine the feasibility of year-round Tetraselmis sp. cultivation in a semi-ORS in Korea for biomass and bioactive lipid production. To maximize biomass productivity of Tetraselmis sp., f medium was selected because it resulted in a significantly higher biomass productivity (1.64 ± 0.03 g/L) and lower omega-6/omega-3 ratio (0.52/1) under laboratory conditions than f/2 medium (0.70/1). Then, we used climatic data-based building information modeling technology to construct a pilot plant of six semi-ORSs for controlling culture conditions, each with a culture volume of 40,000 L. Over 1 year, there were no significant variations in monthly biomass productivity, fatty acid composition, or the omega-6/omega-3 ratio, however, the lipid content correlated significantly with photosynthetic photon flux density. During year-round cultivation from November 2014 to October 2017, areal productivity was gradually increased by increasing medium salinity and injecting CO2 gas into the culture medium. Productivity peaked at 44.01 g/m2/d in October 2017. Throughout the trials, there were no significant differences in average lipid content, which was 14.88 ± 1.26%, 14.73 ± 2.44%, 12.81 ± 2.82%, and 13.63 ± 3.42% in 2014, 2015, 2016, and 2017, respectively. Our results demonstrated that high biomass productivity and constant lipid content can be sustainably maintained under Korean climate conditions.

Endothelin receptor A (ETA), a class A G-protein-coupled receptor (GPCR), is involved in the progression and metastasis of colorectal, breast, lung, ovarian, and prostate cancer. We overexpressed and purified human endothelin receptor type A in Escherichia coli and reconstituted it with lipid and membrane scaffold proteins to prepare an ETA nanodisc as a functional antigen with a structure similar to that of native GPCR. By screening a human naive immune single-chain variable fragment phage library constructed in-house, we successfully isolated a human anti-ETA antibody (AG8) exhibiting high specificity for ETA in the β-arrestin Tango assay and effective inhibitory activity against the ET-1-induced signaling cascade via ETA using either a CHO-K1 cell line stably expressing human ETA or HT-29 colorectal cancer cells, in which AG8 exhibited IC50 values of 56 and 51 nM, respectively. In addition, AG8 treatment repressed the transcription of inhibin βA and reduced the ETA-induced phosphorylation of protein kinase B and extracellular regulated kinase. Furthermore, tumor growth was effectively inhibited by AG8 in a colorectal cancer mouse xenograft model. The human anti-ETA antibody isolated in this study could be used as a potential therapeutic for cancers, including colorectal cancer.

Tryptophanyl-tRNA synthetase 1 (WARS1) is an endogenous ligand of mammalian Toll-like receptors (TLR) 2 and TLR4. Microarray data, using mRNA from WARS1-treated human peripheral blood mononuclear cells (PBMCs), had indicated WARS1 to mainly activate innate inflammatory responses. However, exact molecular mechanism remains to be understood. The triggering receptor expressed on myeloid cells (TREM)-1 is an amplifier of pro-inflammatory processes. We found WARS1 to significantly activate TREM-1 at both mRNA and protein levels, along with its cell surface expression and secretion in macrophages. WARS1 stimulated TREM-1 production via TLR2 and TLR4, mediated by both MyD88 and TRIF, since targeted deletion of TLR4, TLR2, MyD88, and TRIF mostly abrogated TREM-1 activation. Furthermore, WARS1 promoted TREM-1 downstream phosphorylation of DAP12, Syk, and AKT. Knockdown of TREM-1 and inhibition of Syk kinase significantly suppressed the activation of inflammatory signaling loop from MyD88 and TRIF, leading to p38 MAPK, ERK, and NF-&kappa, B inactivation. Finally, MyD88, TRIF, and TREM-1 signaling pathways were shown to be cooperatively involved in WARS1-triggered massive production of IL-6, TNF-&alpha, IFN-&beta, MIP-1&alpha, MCP-1, and CXCL2, where activation of Syk kinase was crucial. Taken together, our data provided a new insight into WARS1&prime, s strategy to amplify innate inflammatory responses via TREM-1.

Correction to: Communications Chemistry https://doi.org/10.1038/s42004-020-0283-4, published online 25 March 2020. The original version of this Article incorrectly designated Yoonmook Kang as a corresponding author and listed their e-mail address in error. This has now been corrected in the PDF and HTML versions of the Article.

We investigated strontium oxide (SrO) as an interlayer material to enhance the UV stability of a CH3NH3PbI3 perovskite solar cell. Moisture and over 400 nm wavelength of light were excluded to investigate the effect of UV light only. Two different interlayer fabrication processes were examined to optimize the performance of this solar cell. Devices fabricated by dipping for 30 min in SrO solution exhibited photoconversion efficiencies of 15.5%, whereas those fabricated with 60-min dipping showed photoconversion efficiencies of 15% and exhibited local Sr agglomeration. Devices with SrO displayed lower initial efficiencies than those without any SrO layer (17.6%), However, a device without SrO retained only 34.4% of its initial efficiency after 100 h of UV exposure. In contrast, SrO-incorporated devices retained almost 60.0% of their initial efficiency. Severe μ-PL mapping intensity degradation was observed in devices that did not include the interlayer, but no degradation was observed in those with the SrO interlayer. This can be attributed to the passivation of the degradation sites by SrO.

One of the most interesting topics in physical science and materials science is the creation of complex wrinkled structures on thin-film surfaces because of their several advantages of high surface area, localized strain, and stress tolerance. In this study, a significant step was taken toward solving limitations imposed by the fabrication of previous artificial wrinkles. A universal method for preparing hierarchical three-dimensional wrinkle structures of thin films on a multiple scale (e.g., nanometers to micrometers) by sequential wrinkling with different skin layers was developed. Notably, this method was not limited to specific materials, and it was applicable to fabricating hierarchical wrinkles on all of the thin-film surfaces tested thus far, including those of metals, two-dimensional and one-dimensional materials, and polymers. The hierarchical wrinkles with multiscale structures were prepared by sequential wrinkling, in which a sacrificial layer was used as the additional skin layer between sequences. For example, a hierarchical MoS2 wrinkle exhibited highly enhanced catalytic behavior because of the superaerophobicity and effective surface area, which are related to topological effects. As the developed method can be adopted to a majority of thin films, it is thought to be a universal method for enhancing the physical properties of various materials.

The effects of tyrosine kinase inhibitors (TKIs) were evaluated on growth inhibition of intracellular Toxoplasma gondii in host ARPE-19 cells. The number of tachyzoites per parasitophorous vacuolar membrane (PVM) was counted after treatment with TKIs. T. gondii protein expression was assessed by western blot. Immunofluorescence assay was performed using Programmed Cell Death 4 (PDCD4) and T. gondii GRA3 antibodies. The TKIs were divided into 3 groups; non-epidermal growth factor receptor (non-EGFR), anti-human EGFR 2 (anti-HER2), and anti-HER2/4 TKIs, respectively. Group I TKIs (nintedanib, AZD9291, and sunitinib) were unable to inhibit proliferation without destroying host cells. Group II TKIs (lapatinib, gefitinib, erlotinib, and AG1478) inhibited proliferation up to 98% equivalent to control pyrimethamine (5 μM) at 20 μM and higher, without affecting host cells. Group III TKIs (neratinib, dacomitinib, afatinib, and pelitinib) inhibited proliferation up to 98% equivalent to pyrimethamine at 1-5 μM, but host cells were destroyed at 10-20 μM. In Group I, TgHSP90 and SAG1 inhibitions were weak, and GRA3 expression was moderately inhibited. In Group II, TgHSP90 and SAG1 expressions seemed to be slightly enhanced, while GRA3 showed none to mild inhibition; however, AG1478 inhibited all proteins moderately. Protein expression was blocked in Group III, comparable to pyrimethamine. PDCD4 and GRA3 were well localized inside the nuclei in Group I, mildly disrupted in Group II, and were completely disrupted in Group III. This study suggests the possibility of a vital T. gondii TK having potential HER2/4 properties, thus anti-HER2/4 TKIs may inhibit intracellular parasite proliferation with minimal adverse effects on host cells.

We characterize wrinkling on the surfaces of prestrained polystyrene sheets coated with thin polytetrafluoroethylene skins using a combination of mechanical strain measurements and 3D finite element simulations. The simulations show that wrinkle wavelength increases with skin thickness, in agreement with a well-known continuum model and recent experiments. The wrinkle amplitudes also increase with strain. Nanoinclusions, such as holes and patterned lines, influence wrinkle patterns over limited distances, and these distances are shown to scale with the wrinkle wavelengths. Good agreement between experimental and simulated influence distances is observed. The inclusions provide strain relief, and they behave as if they are attracting adjacent material when the sheets are under strain. The wrinkles have stiffnesses in much the same way as do polymers (but at different length scales), a property that is quantified for polymers using persistence lengths. We show that the concept of persistence length can be useful in characterizing the wrinkle properties that we have observed. However, the calculated persistence lengths do not vary systematically with thickness and strain, as interactions between neighboring wrinkles produce confinement that is analogous to the kinetic confinement of polymers.

We show that submicron-sized patterns can be imprinted into soft, recombinant-engineered protein hydrogels (here elastin-like proteins, ELP) by transferring wavy patterns from polydimethylsiloxane (PDMS) molds. The high-precision topographical tunability of the relatively stiff PDMS is translated to a bio-responsive, soft material, enabling topographical cell response studies at elastic moduli matching those of tissues. Aligned and unaligned wavy patterns with mold periodicities of 0.24-4.54 μm were imprinted and characterized by coherent anti-Stokes Raman scattering and atomic force microscopy. The pattern was successfully transferred down to 0.37 μm periodicity (width in ELP: 250 ± 50 nm, height: 70 ± 40 nm). The limit was set by inherent protein assemblies (diameter: 124-180 nm) that formed due to lower critical solution temperature behavior of the ELP during molding. The width/height of the ELP ridges depended on the degree of hydration; from complete dehydration to full hydration, ELP ridge width ranged from 79 ± 9% to 150 ± 40% of the mold width. The surface of the ridged ELP featured densely packed protein aggregates that were larger in size than those observed in bulk/flat ELP. Adipose-derived stem cells (ADSCs) oriented along hydrated aligned patterns with periodicities ≥0.60 μm (height ≥170 ± 100 nm), while random orientation was observed for smaller distances/amplitudes, as well as flat and unaligned wavy ELP surfaces. Hence, micro-molding of ELP is a promising approach to create tissue-mimicking, hierarchical architectures composed of tunable micron-sized structures with nano-sized protein aggregates, which opens the way for orthogonal screening of cell responses to topography and cell-adhesion ligands at relevant elastic moduli.

Human lysophosphatidic acid receptor 1 (LPA1 ) is a G-protein coupled receptor that mediates various biological functions such as proliferation, platelet aggregation, smooth muscle contraction, and tumor cell invasion. For dissection of the molecular function of LPA1 , a recombinant LPA1 was overexpressed in Escherichia coli membrane fractions and purified to homogeneity by single affinity chromatography. The purified LPA1 was stabilized with an amphiphilic polymer that was synthesized by the coupling of octylamine, glucosamine, and diethylaminoproylamine at the carboxylic groups of poly-γ-glutamic acid. The complex of purified LPA1 and amphiphilic polymer showed a monodisperse oligomer and specific binding to LPA with apparent Ki values of 30 μM. Compared with the Gs protein, it also showed selective binding to the alpha subunit of the Gi protein. These results indicate that recombinant LPA1 in an amphiphilic polymer complex has an active conformation for interaction with ligands and G-proteins.

This paper reports a scalable approach to achieve spatially selective graphene functionalization using multiscale wrinkles. Graphene wrinkles were formed by relieving the strain in thermoplastic polystyrene substrates conformally coated with fluoropolymer and graphene skin layers. Chemical reactivity of a fluorination process could be tuned by changing the local curvature of the graphene nanostructures. Patterned areas of graphene nanowrinkles and crumples followed by a single-process plasma reaction resulted in substrates with regions having different fluorination levels. Notably, conductivity of the functionalized graphene nanostructures could be locally tuned as a function of feature size without affecting the mechanical properties.

Fabricating perovskite on textured silicon surface is important for maximizing current density and the power conversion efficiency (PCE) of perovskite/silicon tandem solar cells. However, producing conformal perovskite on textured silicon surface is difficult because most of high efficiency perovskite solar cells have been produced by solution based process. Herein, we investigated possibility of producing perovskite solar cells on textured silicon surface by dry two-step conversion process and analyzing them with periodically patterned texture and photoluminescence mapping. Thickness scale difference between perovskite and silicon substrate have induced focusing problems.

Accuracy of the Yb optical lattice clock being developed at KRISS has been improved due to better measurements of light shifts and collisional shift. Its accuracy uncertainty is now 5.6×10$^{\mathbf {-17}}$, three times better than our previous result. The second Yb optical lattice clock is now being built for lower blackbody radiation shift using a thermal shield made of copper. Its preliminary estimation of temperature uncertainty is below 50 mK, which corresponds to frequency uncertainty of low 10$^{\mathbf {-18}}$level.

A new clock laser system using an optical cavity with $4.8 \times 10^-17$ thermal noise limit has been developed for rapid evaluation of ytterbium lattice clocks. This was realized by using a 30-cm-long ULE cavity, fused-silica mirror substrates, and crystalline mirror coatings. The frequency stability of the beating signal between the new clock laser and the old clock laser was limited by the latter. The linewidth and the frequency stability of the new clock laser will be measured by comparing the frequency between two similar systems.

Nanoscale wrinkling on the surfaces of polymer-based materials can be precisely controlled by depositing thin metal films of varying thicknesses. The deposition of these films fundamentally alters the mechanical properties of the substrates in ways that are not simply described using traditional continuum mechanical frameworks. In particular, we find, by modeling within a finite element analysis approach, that the very act of depositing a metal film may alter the Young's modulus of the polymer substrate to depths of up to a few hundred nanometers, creating a modified interfacial skin layer. We find that simulated wrinkle patterns reproduce the experimentally observed features only when the modulus of this surface layer varies by more than ∼500 nm and is described using a sigmoidal gradient multiplier.

Transglutaminase 2 (TGase 2) catalyzes a crosslink between protein bound-glutamine and -lysine. We proposed the mechanism of TGase 2 activation depends on conformation change from unfolded monomer to unfolded dimer. We found that TGase 2 has temperature-sensitive conformation change system at 30 °C. Small-angle X-ray scattering analysis showed that the enzyme was maintained as an unfolded monomer at temperatures below 30 °C, but changed to an unfolded dimer at over 30 °C. Mass analysis revealed that the C-terminus of TGase 2 was the critical region for dimerization. Furthermore, this conformational switch creates new biochemical reactivity that catalyzed inter-molecular crosslink at above 30 °C as an unfolded dimer of TGase 2 while catalyzed intra-molecular crosslink at below 30 °C as an unfolded monomer of TGase 2. The mechanism of TGase 2 activation depends on temperature-sensitive conformation change from unfolded monomer to unfolded dimer at over 30 °C. Furthermore, inter-molecular crosslinking activity is generated by the dimeric form of TGase 2. TGase 2 switches its conformation from a monomer to a dimer following a change in temperature, which engendered unique catalytic function of enzyme as inter-molecular crosslinking activity with calcium.

In this study, perovskite thin films (PFs) were conformally deposited on 100 cm2 textured silicon substrates using a two-step vacuum process. The PFs were fabricated by converting thin films of a sputtered-PbO precursor using the chemical vapor deposition process. The conversion of PbO thin films into PFs was confirmed by X-ray diffractometry. The uniformity of reflectance and thickness was higher than 86% and 92%, respectively, on 100 cm2 textured substrate. We appliedmethylammoniumvapor treatment for complete conversion without residual layer and the power conversion efficiency was 10.2% on a glass/FTO/TiO2/MAPbI3/Spiro-MeOTAD/Au structure.

Three-dimensional (3D) hierarchical wrinkles can be generated on prestrained thermoplastic substrates by sequential cycles of skin layer growth followed by the release of prestrain. However, no mechanics models have explained the formation of multigenerational nanostructures using this nanofabrication process. This article describes an analytical model that can represent multiscale wrinkles with arbitrary numbers of generations. Structural features including wrinkle wavelengths and amplitudes on the nanoscale that are predicted by minimizing the total deformation energy of the system. The calculated wavelengths in each generation are in good agreement with experiment. Our mathematical approach provides design principles for achieving multigenerational hierarchical structures.

In general, expression of transglutaminase 2 (TGase 2) is upregulated in renal cell carcinoma (RCC), resulting in p53 instability. Previous studies show that TGase 2 binds to p53 and transports it to the autophagosome. Knockdown or inhibition of TGase 2 in RCC induces p53-mediated apoptosis. Here, we screened a chemical library for TGase 2 inhibitors and identified streptonigrin as a potential therapeutic compound for RCC. Surface plasmon resonance and mass spectroscopy were used to measure streptonigrin binding to TGase 2. Mass spectrometry analysis revealed that streptonigrin binds to the N-terminus of TGase 2 (amino acids 95&ndash, 116), which is associated with inhibition of TGase 2 activity in vitro and with p53 stabilization in RCC. The anti-cancer effects of streptonigrin on RCC cell lines were demonstrated in cell proliferation and cell death assays. In addition, a single dose of streptonigrin (0.2 mg/kg) showed marked anti-tumor effects in a preclinical RCC model by stabilizing p53. Inhibition of TGase 2 using streptonigrin increased p53 stability, which resulted in p53-mediated apoptosis of RCC. Thus, targeting TGase 2 may be a new therapeutic approach to RCC.

Previously we have demonstrated transglutaminase 2 (TGase 2) inhibition abrogated renal cell carcinoma (RCC) using GK921 (3-(phenylethynyl)-2-(2-(pyridin-2-yl)ethoxy)pyrido[3,2-b]pyrazine), although the mechanism of TGase 2 inhibition remains unsolved. Recently, we found that the increase of TGase 2 expression is required for p53 depletion in RCC by transporting the TGase 2 (1-139 a.a)-p53 complex to the autophagosome, through TGase 2 (472-687 a.a) binding p62. In this study, mass analysis revealed that GK921 bound to the N terminus of TGase 2 (81-116 a.a), which stabilized p53 by blocking TGase 2 binding. This suggests that RCC survival can be stopped by p53-induced cell death through blocking the p53-TGase 2 complex formation using GK921. Although GK921 does not bind to the active site of TGase 2, GK921 binding to the N terminus of TGase 2 also inactivated TGase 2 activity through acceleration of non-covalent self-polymerization of TGase 2 via conformational change. This suggests that TGase 2 has an allosteric binding site (81-116 a.a) which changes the conformation of TGase 2 enough to accelerate inactivation through self-polymer formation.

Intrinsically disordered proteins (IDPs) represent approximately 30% of the human genome and play key roles in cell proliferation and cellular signaling by modulating the function of target proteins via protein-protein interactions. In addition, IDPs are involved in various human disorders, such as cancer, neurodegenerative diseases, and amyloidosis. To understand the underlying molecular mechanism of IDPs, it is important to study their structural features during their interactions with target proteins. However, conventional biochemical and biophysical methods for analyzing proteins, such as X-ray crystallography, have difficulty in characterizing the features of IDPs because they lack an ordered three-dimensional structure. Here, we present biochemical and biophysical studies on nucleolar phosphoprotein 140 (Nopp140), which mostly consists of disordered regions, during its interaction with casein kinase 2 (CK2), which plays a central role in cell growth. Surface plasmon resonance and electron paramagnetic resonance studies were performed to characterize the interaction between Nopp140 and CK2. A single-molecule fluorescence resonance energy transfer study revealed conformational change in Nopp140 during its interaction with CK2. These studies on Nopp140 can provide a good model system for understanding the molecular function of IDPs.

Soft skin layers on elastomeric substrates are demonstrated to support mechano-responsive wrinkle patterns that do not exhibit cracking under applied strain. Soft fluoropolymer skin layers on pre-strained poly(dimethylsiloxane) slabs achieved crack-free surface wrinkling at high strain regimes not possible by using conventional stiff skin layers. A side-by-side comparison between the soft and hard skin layers after multiple cycles of stretching and releasing revealed that the soft skin layer enabled dynamic control over wrinkle topography without cracks or delamination. We systematically characterized the evolution of wrinkle wavelength, amplitude, and orientation as a function of tensile strain to resolve the crack-free structural transformation. We demonstrated that wrinkled surfaces can guide water spreading along wrinkle orientation, and hence switchable, anisotropic wetting was realized.

Difficulties in the extraction of membrane proteins from cell membrane and their solubilization in native conformations have hindered their structural and biochemical analysis. To overcome these difficulties, an amphipathic polypeptide was synthesized by the conjugation of octyl and glucosyl groups to the carboxyl groups of poly-γ-glutamic acid (PGA). This polymer, called amphipathic PGA (APG), self-assembles as mono-disperse oligomers consisted of 4–5 monomers. APG shows significantly low value of critical micelle concentration and stabilization activity toward membrane proteins. Most of the sodium dodecyl sulfate (SDS)-solubilized membrane proteins from Escherichia coli remain soluble state in the presence of APG even after the removal of SDS. In addition, APG stabilizes purified 7 transmembrane proteins such as bacteriorhodopsin and human endothelin receptor Type A (ETA) in their active conformations. Furthermore, ETA in complex with APG is readily inserted into liposomes without disrupting the integrity of liposomes. These properties of APG can be applied to overcome the difficulties in the stabilization and reconstitution of membrane proteins.

Bacterial resistance to many existing antibiotics is a growing health concern worldwide. There is an urgent need to identify new antibiotics with unexploited modes of action. Peptide deformylase (PDF) is an essential enzyme involved in N-terminal protein processing in eubacteria but not in higher organisms. Therefore, PDF is considered an attractive target for the development of novel antibiotics. Here, we report the structures of the PDFs from Enterococcus faecalis (EfPDF) and Streptococcus pyogenes (SpyPDF) complexed with actinonin at 1.4 and 2.1 A resolutions, respectively. Actinonin, a naturally occurring, highly potent inhibitor, is bound tightly at the active site. The conformation of actinonin in the EfPDF and SpyPDF complexes was similar to those of all others. The detailed information from this study will facilitate the development of novel antibacterial molecules.

The pro-apoptotic BCL-2 family protein BID activates BAK and/or BAX, which form oligomeric pores in the mitochondrial outer membrane. This results in the release of cytochrome c into the cytoplasm, initiating the apoptotic cascade. Here, we utilized liposomes encapsulating sulfo-rhodamine at a controlled temperature to improve upon a previously reported assay system with enhanced sensitivity and specificity for measuring membrane permeabilization by BID-dependent BAK activation. BAK activation was inhibited by BCL-XL protein but not by a mutant protein with impaired anti-apoptotic activity. With the assay system, we screened a chemical library and identified several compounds including trifluoperazine, a mitochondrial apoptosisinduced channel blocker. It inhibited BAK activation by direct binding to BAK and blocking the oligomerization of BAK.

The main function of methionine sulfoxide reductases (Msr) in many organisms is to protect cells against oxidative stress caused by the catalyzed reduction of oxidized methionine to normal methionine. In a few micro-organisms, the existence of Msr as a fusion protein on a single polypeptide, MsrAB, was reported. However, Msr generally exists as separate enzymes MsrA and MsrB. Here, MsrAB from Helicobacter pylori (HpMsrAB) was overexpressed in Escherichia coli, purified, and crystallized to determine its structure. HpMsrAB X-ray diffraction data were collected to the resolution of 3.3 A, and the crystals were found to belong to the tetragonal space group P41212, with the unit cell parameters a =100.91, b =100.91, and c =160.08 A. The crystals corresponded to 5.38 A3 Da−1 of Matthews coefficient and 77.2% solvent content from the molecular replacement suggest that there is a single molecule in an asymmetric unit. Due to their unusually high solvent content, diffraction of these crystals only reach a resolution of 3.3 A. A preliminary solution was determined by molecular replacement. Further refinement of the structure is in progress.

Single-chain variable fragments of antibodies (scFv) specific to 2,4-dinitrotoluene (DNT) were isolated from a phage library displaying synthetic human scFv fragments with 6 diversified complementary determining regions (CDRs). A DNT derivative that contained an extended amine group was synthesized and conjugated to the NHS-group that was linked to magnetic beads. Phages specific to the immobilized DNT derivatives were isolated from the library after 4 rounds of sequential binding and elution processes. The displayed scFv fragments from the isolated phages showed consensus CDR sequences. One DNT-specific scFv was expressed in E. coli and purified using Ni-affinity chromatography. The purified DNT-specific scFv binds specifically to the immobilized DNT-derivative with value of M. The scFv and DNT interaction was not disrupted by the addition of 4-nitrotoluene or benzoic acid. These data demonstrate that the screened scFv from the phage displayed library could be used for selective and sensitive detection of explosives such as TNT.

Nucleolar phosphoprotein 140 (Nopp140) is a nucleolar protein, more than 80% of which is disordered. Previous studies have shown that the C-terminal region of Nopp140 (residues 568-596) interacts with protein kinase CK2α, and inhibits the catalytic activity of CK2. Although the region of Nopp140 responsible for the interaction with CK2α was identified, the structural features and the effect of this interaction on the structure of Nopp140 have not been defined due to the difficulty of structural characterization of disordered protein. In this study, the disordered feature of Nopp140 and the effect of CK2α on the structure of Nopp140 were examined using single-molecule fluorescence resonance energy transfer (smFRET) and electron paramagnetic resonance (EPR). The interaction with CK2α was increased conformational rigidity of the CK2α-interacting region of Nopp140 (Nopp140C), suggesting that the disordered and flexible conformation of Nopp140C became more rigid conformation as it binds to CK2α. In addition, site specific spin labeling and EPR analysis confirmed that the residues 574-589 of Nopp140 are critical for binding to CK2α. Similar technical approaches can be applied to analyze the conformational changes in other IDPs during their interactions with binding partners.

Nopp140 is a highly phosphorylated protein that resides in the nucleolus of mammalian cell and is involved in the biogenesis of the nucleolus. It interacts with a variety of proteins related to the synthesis and assembly of the ribosome. It also can bind to a ubiquitous protein kinase CK2 that mediates cell growth and prevents apoptosis. We found that Nopp140 is an intrinsically unfolded protein (IUP) lacking stable secondary structures over its entire sequence of 709 residues. We discovered that mitoxantrone, an anticancer agent, was able to enhance the interaction between Nopp140 and CK2 and maintain suppressed activity of CK2. Surface plasma resonance studies on different domains of Nopp140 show that the C-terminal region of Nopp140 is responsible for binding with mitoxantrone. Our results present an interesting example where a small chemical compound binds to an intrinsically unfolded protein (IUP) and enhances protein-protein interactions.

In this study, the kinetic properties of wild-type and C117D mutant H. influenzae MurA (Hi MurA), which catalyzes the first reaction in the biosynthetic pathway of the cell wall, were characterized. Purified recombinant Hi MurA was active at pH values ranging from pH 5.5 to pH 10, and its (UNAG), (PEP), and values were measured to be 31 , 24 , and 210 , respectively. Hi MurA activity was effectively inhibited by fosfomycin with an value of 60 . Hi MurA contains a cysteine residue (C117) at the loop region near the PEP binding, whereas MurA from fosfomycin resistant Mycobaterium tuberculosis or Chlamydia trachomatis contain an aspartate residue instead of the cysteine at the corresponding site. Aspartate substitution of Cys117 in Hi MurA shifted its optimum pH from 7.8 to 6.0. In addition, the values for UNAG and PEP were increased to 160 and 150 , respectively, and the value was significantly reduced to 41 . Furthermore, the C117D mutant form of Hi MurA was not inhibited by 1 mM fosfomycin. These results indicate that the Cys117 of Hi MurA is the binding site of fosfomycin and plays an important role in the fast turnover of the catalytic reaction.

Vertical alignment (VA) of a liquid crystal display (LCD) device with a stable pretilt angle has been achieved on ion-bombarded silicon nitride (SiN x) surfaces. The surface energy variation of the SiN x surface with the bonding conversion achieved via ion beam bombardment makes it possible to control the liquid crystal (LC) pretilt angle. X-ray photoelectron spectroscopy revealed that the vertical orientation of the LC molecules occurs on the SiO 2 surface and that this orientation is directionally transformed upon ion bombardment of SiN x thin films. Moreover, the upgraded electro-optical characteristics of VA-LCDs showed potential for high-performance LCD applications on modified SiN x surfaces.

Biomolecules specific to explosives can be exploited as chemical sensors. Peptides specific to immobilized dinitrotoluene (DNT) were identified using a phage display library. A derivative of DNT that contained an extended amine group, 4-(2,4-dinitrophenyl)butan-1-amine, was synthesized and immobilized using a self-assembled monolayer surface on gold. Filamentous M13 phages displaying random sequences of 12-mer peptides specific to the immobilized DNT-derivate were isolated from the M13 phage library by biopanning. A common peptide sequence was identified from the isolated phages and the synthesized peptides showed selective binding to DNT. When the peptide was immobilized on a quartz crystal microbalance (QCM) chip, it showed a binding signal to DNT, while toluene barely showed significant binding to the QCM chip. These results demonstrate that peptides screened by biopanning against immobilized DNT can be useful for quick and accurate detection of DNT.

This paper describes polymeric nanostructures with dynamically tunable wetting properties. Centimeter-scale areas of monolithic nanoridges can be generated by strain relief of thermoplastic polyolefin films with fluoropolymer skin layers. Changing the amount of strain results in polyolefin ridges with aspect ratios greater than four with controlled feature densities. Surface chemistry and topography are demonstrated to be able to be tailored by SF6 -plasma etching to access multiple wetting states: Wenzel, Cassie-Baxter, and Cassie-impregnating states. Reversible transitions among the wetting states can be realized in a programmable manner by cyclic stretching and reshrinking the patterned substrates without delamination and cracking.

Sum frequency generation was utilized to obtain a yellow laser with the wavelength of 578.4 nm for a probe laser of an Yb lattice clock. The output of an Nd:YAG laser with wavelength of 1319 nm and that of an Yb-fiber laser with wavelength of 1030 nm were passed through a waveguided periodically-poled lithium niobate (WG-PPLN) for sum frequency generation. It is required that the probe laser has a linewidth of the order of 1 Hz to fully resolve the Yb lattice clock transition. Thus, the linewidth of the probe laser was reduced by stabilizing the frequency to a super-cavity. This was made of ULE with a low thermal expansion coefficient, and was mounted on an active vibration-isolation table at the optimal point for the reduced sensitivity to vibration. Also, this was installed in a vacuum chamber, and the temperature was stabilized to 1 mK level. This system was installed in an acoustic enclosure to block acoustic noise. The finesse of the super-cavity was measured to be 380 000 from the photon life time of the cavity.

The aligned liquid crystals (LCs) display on SiNx thin films using ion-beam (IB) irradiation was studied with controllability of pretilt angle depending on incident energies of the IB. The LCs alignment property for the SiNx thin films were observed to verify the practical application potential. A good LCs alignment of vertical alignment LCs cells on SiNx thin film surfaces irradiated with incident IB energy of 1800eV was achieved. The atomic force microscopy (AFM) images of LCs on SiNx thin film surfaces irradiated with IB energy was used for the surface analysis.

This study was carried out to screen and identify the chitinase and chitosanase producing microorganisms from the feces of calves medicated DFM sincluding chitin in order to do the immune fortification of Korean Native calves. Ten isolates were grown in the medium containing chitin and chitosan that had more than 10 5 cfu/g in feces. Among these 10 strains, 2 strains (HANDI 110 and HANDI 309) had the chitinase activities and 2 strains (HANWOO and HANYOO) had the chitosanase activities in calves' feces. They showed no reaction in hemolysis tests by utilizing chitin and chitosan. The results from morphological, physicochemical and genetical identification indicated the HANDI 110 as a strain of Escherichia fergusonii, HANDI 309 was identified as a strain of Acinetobacter parvus, HANWOO was identified as a strain of Comamonas koreensis, and HANYOO as a strain of Chryseobacterium indologenes.

We investigated the electrical properties of polycrystalline silicon (poly-Si) thin film transistors (TFTs) employing field-enhanced solid phase crystallization (FESPC). An n+ amorphous silicon (n+ a-Si) layer was deposited to improve the contact resistance between the active Si and source/drain (S/D) metal instead of ion doping. By using C–V measurement method, we could explain the diffused phosphorous ions (P+ ions) on the channel surface caused a negatively shifted threshold voltage (VTH) of −7.81 V at a drain bias of 0.1 V, and stretched out a subthreshold swing (S) of 1.698 V/dec. This process was almost compatible with the widely used hydrogenated amorphous silicon (a-Si:H) TFT fabrication process and also offers a better uniformity when compared to the conventional laser-crystallized poly-Si TFT process because of non-laser crystallization.

Camptothecin (CPT) is a naturally occurring alkaloid that shows promise in antitumor activity in vitro against various tumor cell lines. Its potential clinical uses, however, are hindered by a lack of reaction selectivity and poor water solubility. Presented herein is a novel polyrotaxane (PR)-based delivery system that could potentially lead to a highly effective yet less toxic CPT therapy. The approach involves the synthesis of the PR-CPT conjugates via hydrolyzable linkages. To enhance the therapeutic efficacy of CPT, a cell-penetrating peptide, LMWP, is linked to the conjugate to allow specific, intratumoral delivery of CPT. To avoid nonselective uptake of the conjugates by normal tissues following administration, the cell-penetrating function of LMWP on the conjugates is masked by heparin binding. This system was designed such that after accumulation at the tumor via the enhanced permeability and retention (EPR) effect, protamine can be subsequently administered to unmask heparin inhibition on LMWP, permitting intracellular uptake of the LMWP-PR-CPT conjugates. Once inside the tumor, CPT molecules are detached from the PR chain by hydrolysis, yielding a sustained concentration of CPT within tumor cells. In this paper, we demonstrated the in vitro feasibility of this delivery system. The LMWP-PR-CPT conjugates yielded a sevenfold increase in the overall CPT solubility, as well as a sustained release of CPT over a period of more than 7 days. Intracellular uptake of these conjugates by A2780 human ovarian cancer cells and regulation of such uptake by heparin and protamine were tested by MTT assay and confocal/flow cytometric methods, respectively.