A highly sensitive fluorescent probe that quantifies transthyretin in human plasma as an early diagnostic tool of Alzheimer's disease.

The development of sensitive and reliable fluorescent probes for the early diagnosis of Alzheimer's disease (AD) is highly challenging and plays an important role in achieving effective treatments. Herein, we designed and synthesized an indole-based fluorophore for TTR in human plasma, an important hallmark of AD pathogenesis. This robust and simple fluorescent method allows quantification of TTR in the complex biological matrix.

Functional characterization of a novel loss-of-function mutation of PRPS1 related to early-onset progressive nonsyndromic hearing loss in Koreans (DFNX1): Potential implications on future therapeutic intervention.

BACKGROUND: The symptoms of phosphoribosyl pyrophosphate synthetase 1 (PRPS1) deficiency diseases have been reported to be alleviated by medication. In the present study, we report biochemical data that favor PRPS1 deficiency-related hearing loss as a potential target for pharmaceutical treatment. METHODS: We recruited 42 probands from subjects aged less than 15 years with a moderate degree of nonsyndromic autosomal-recessive or sporadic sensorineural hearing loss (SNHL) in at least one side. Molecular genetic testing, including targeted exome sequencing (TES) of 129 genes for deafness, and in silico prediction were performed. RESULTS: A strong candidate variant (p.A82P) of PRPS1 is co-segregated with SNHL in X-linked recessive inheritance from one Korean multiplex SNHL family. Subsequent measurement of in vitro enzymatic activities of PRPS1 from erythrocytes of affected and unaffected family members, as well as unrelated normal controls, confirmed a pathogenic role of this variant. In detail, compared to normal hearing controls (0.23-0.26 nmol/ml/h), the proband, the affected sibling and their normal hearing mother demonstrated a significantly decreased PRPS1 enzymatic activity (0.07, 0.03 and 0.11 nmol/ml/h, respectively). This novel loss-of-function mutation of PRPS1 (p.A82P) is the ninth and sixth most reported mutation in the world and in Asia, respectively. CONCLUSIONS: DFNX1 was found to account for approximately 2.4% (1/42) of moderate SNHL in a Korean pediatric population. Confirmation of PRPS1 activity deficiency and an audiologic phenotype that initially begins in a milder form of SNHL, as in our family, should indicate the need for rigorous genetic screening as early as possible.

The formation of right-handed and left-handed chiral nanopores within a single domain during amino acid self-assembly on Au(111).

We report the formation of both right- and left-handed chiral nanopores within a single domain during the self-assembly of an amino acid derivative on an inert Au(111) surface using STM. DFT calculations employed to rationalize this unusual result identified that intermolecular interactions between chiral, windmill-shaped tetramers are crucial for self-assembly.

Unraveling of Enigmatic Hearing-Impaired GJB2 Single Heterozygotes by Massive Parallel Sequencing: DFNB1 or Not?

The molecular etiology of nonsyndromic sensorineural hearing loss (SNHL) in subjects with only one detectable autosomal recessive GJB2 mutation is unclear. Here, we report GJB2 single heterozygotes with various final genetic diagnoses and suggest appropriate diagnostic strategies. A total of 160 subjects with SNHL without phenotypic markers were screened for GJB2 mutations. Single-nucleotide variants or structural variations within the DFNB1 locus or in other deafness genes were examined by Sanger sequencing, breakpoint PCR, and targeted exome sequencing (TES) of 129 deafness genes. We identified 27 subjects with two mutations and 10 subjects with only one detectable mutation in GJB2. The detection rate of the single GJB2 mutation among the 160 SNHL subjects in the present study (6.25%) was higher than 2.58% in normal hearing controls in Korean. The DFNB1 was clearly excluded as a molecular etiology in four (40%) subjects: other recessive deafness genes (N = 3) accounted for SNHL and the causative gene for the other non-DFNB1 subject (N = 1) was not identified. The etiology of additional two subjects was potentially explained by digenic etiology (N = 2) of GJB2 with MITF and GJB3, respectively. The contribution of the single GJB2 mutation in the four remaining subjects is unclear. Comprehensive diagnostic testing including TES is prerequisite for understanding GJB2 single heterozygotes.

Enhancement of Photo-Oxidation Activities Depending on Structural Distortion of Fe-Doped TiO2 Nanoparticles.

To design a high-performance photocatalytic system with TiO2, it is necessary to reduce the bandgap and enhance the absorption efficiency. The reduction of the bandgap to the visible range was investigated with reference to the surface distortion of anatase TiO2 nanoparticles induced by varying Fe doping concentrations. Fe-doped TiO2 nanoparticles (Fe@TiO2) were synthesized by a hydrothermal method and analyzed by various surface analysis techniques such as transmission electron microscopy, Raman spectroscopy, X-ray diffraction, scanning transmission X-ray microscopy, and high-resolution photoemission spectroscopy. We observed that Fe doping over 5 wt.% gave rise to a distorted structure, i.e., Fe2Ti3O9, indicating numerous Ti(3+) and oxygen-vacancy sites. The Ti(3+) sites act as electron trap sites to deliver the electron to O2 as well as introduce the dopant level inside the bandgap, resulting in a significant increase in the photocatalytic oxidation reaction of thiol (-SH) of 2-aminothiophenol to sulfonic acid (-SO3H) under ultraviolet and visible light illumination.

Comparative study of photocatalytic activities of hydrothermally grown ZnO nanorod on Si(001) wafer and FTO glass substrates.

ZnO nanorods have been grown on Si(001) wafer and fluorine-doped tin oxide (FTO) glass substrates for 1 and 4 h with the hydrothermal methods. The morphologies and photocatalytic activities of the ZnO nanorods were found to depend on the substrates. We investigated their properties by using spectroscopic analysis and demonstrated that the shape of nanorod and the ratios of external defects can be controlled by varying the substrates. Our experiments revealed that the nanorods grown on Si(001) have a single-crystalline wurtzite structure with (002) facets and that the number of surface oxygen defects increases with their length as the growth time increases. The nanorods grown on Si(001) have different facets, in particular wider (002) facets, and a higher ratio of the oxygen defect than the nanorods on FTO glass substrate. Moreover, the photocatalytic activities with respect to 2-aminothiophenol (2-ATP) of these nanorods were investigated with high-resolution photoemission spectroscopy (HRPES). We demonstrated that their photocatalytic activity is influenced by the ratios of surface oxygen defects, which varies with the substrate surface.

Strong founder effect of p.P240L in CDH23 in Koreans and its significant contribution to severe-to-profound nonsyndromic hearing loss in a Korean pediatric population.

BACKGROUND: Despite the prevalence of CDH23 mutations in East Asians, its large size hinders investigation. The pathologic mutation p.P240L in CDH23 is common in East Asians. However, whether this mutation represents a common founder or a mutational hot spot is unclear. The prevalence of CDH23 mutations with prelingual severe-to-profound sporadic or autosomal recessive sensorineural hearing loss (arSNHL) is unknown in Koreans. METHODS: From September 2010 to October 2014, children with severe-to-profound sporadic or arSNHL without phenotypic markers, and their families, were tested for mutations in connexins GJB2, GJB6 and GJB3. Sanger sequencing of CDH23 p.P240L was performed on connexin-negative samples without enlarged vestibular aqueducts (EVA), followed by targeted resequencing of 129 deafness genes, including CDH23, unless p.P240L homozygotes were detected in the first screening. Four p.P240L-allele-linked STR markers were genotyped in 40 normal-hearing control subjects, and the p.P240L carriers in the hearing-impaired cohort, to identify the haplotypes. RESULTS: Four (3.1 %) of 128 children carried two CDH23 mutant alleles, and SLC26A4 and GJB2 accounted for 18.0 and 17.2 %, respectively. All four children showed profound nonsyndromic SNHL with minimal residual hearing. Interestingly, all had at least one p.P240L mutant allele. Analysis of p.P240L-linked STR markers in these children and other postlingual hearing-impaired adults carrying p.P240L revealed that p.P240L was mainly carried on a single haplotype. CONCLUSIONS: p.P240L contributed significantly to Korean pediatric severe arSNHL with a strong founder effect, with implications for future phylogenetic studies. Screening for p.P240L as a first step in GJB2-negative arSNHL Koreans without EVA is recommended.

Residual Hearing in DFNB1 Deafness and Its Clinical Implication in a Korean Population.

INTRODUCTION: The contribution of Gap junction beta-2 protein (GJB2) to the genetic load of deafness and its mutation spectra vary among different ethnic groups. OBJECTIVE: In this study, the mutation spectrum and audiologic features of patients with GJB2 mutations were evaluated with a specific focus on residual hearing. METHODS: An initial cohort of 588 subjects from 304 families with varying degrees of hearing loss were collected at the otolaryngology clinics of Seoul National University Hospital and Seoul National University Bundang Hospital from September 2010 through January 2014. GJB2 sequencing was carried out for 130 probands with sporadic or autosomal recessive non syndromic hearing loss. The audiograms were evaluated in the GJB2 mutants. RESULTS: Of the 130 subjects, 22 (16.9%) were found to carry at least one mutant allele of GJB2. The c.235delC mutation was shown to have the most common allele frequency (39.0%) among GJB2 mutations, followed by p.R143W (26.8%) and p.V37I (9.8%). Among those probands without the p.V37I allele in a trans configuration who showed some degree of residual hearing, the mean air conduction thresholds at 250 and 500 Hz were 57 dB HL and 77.8 dB HL, respectively. The c.235delC mutation showed a particularly wide spectrum of hearing loss, from mild to profound and significantly better hearing thresholds at 250 Hz and 2k Hz than in the non-p.V37I and non-235delC nonsyndromic hearing loss and deafness 1(DFNB1) subjects. CONCLUSION: Despite its reputation as the cause of severe to profound deafness, c.235delC, the most frequent DFNB1 mutation in our cohort, caused a wide range of hearing loss with some residual hearing in low frequencies. This finding can be of paramount help for prediction of low frequency hearing thresholds in very young DFNB1 patients and highlights the importance of soft surgery for cochlear implantation in these patients.

Investigation of the interaction between a novel unnatural chiral ligand and reactant on palladium for asymmetric hydrogenation.

We report about the mechanistic studies of the reaction between a newly synthesized (S)-2-((R)-3H-dinaphtho[2,1-c:1',2'-e]azepin-4(5H)-yl)-2-phenylethanol based on the binaphthyl skeleton and (E)-2-methyl-5-phenylpent-2-enoic acid for the asymmetric hydrogenation of α,ß-unsaturated acids with heterogeneous palladium catalysts. The specific interactions between the chiral ligand and reactant were investigated in solution with palladium nanoparticles, as well as under ultrahigh vacuum (UHV) conditions on the palladium metal surface in the absence of hydrogen. The reactions were explored using nuclear magnetic resonance (NMR) spectroscopy, scanning tunneling microscopy (STM), and high-resolution photoemission spectroscopy (HRPES) combined with density functional theory (DFT) calculations. A NMR study identified the interaction between both molecules with palladium nanoparticles in solution. In addition, STM and HRPES studies revealed the spatial distribution and configuration of both compounds on the palladium metal surface under UHV conditions. The theoretical results support the experimental results with respect to the interaction energy value. It was found that the reaction between the ligand and reactant occurs with hydrogen bonding on palladium surface, simultaneously. The present study provides mechanistic details of the asymmetric hydrogenation reaction, which bears a correlation between the ligand, reactant, and catalyst during the reaction.

Ionic-liquid-derived, water-soluble ionic cellulose.

A new type of water-soluble ionic cellulose was obtained by means of the dissolution of cellulose in dimethylimidazolium methylphosphite at elevated temperatures over 120 °C. FTIR spectroscopy, (1)H and (13)C NMR spectroscopy, and elemental analysis results revealed that the repeating unit of the water-soluble cellulose consists of a dialkylimidazolium cation and a phosphite anion bonded to cellulose. The degree of phosphorylation on the cellulose chain was between 0.4 and 1.3 depending on the reaction temperature and time. With an increasing degree of phosphorylation, water solubility was increased. Scanning electron microscopy and X-ray diffraction analyses revealed that the cellulose crystalline phase in the parent crystalline cellulose changed to an amorphous phase upon transformation into ionic cellulose. Thermogravimetric analysis showed the prepared phosphorylated cellulose was stable over 250 °C and a substantial amount of residue remained at 500 °C.

Sunitinib inhibits papillary thyroid carcinoma with RET/PTC rearrangement but not BRAF mutation.

Sunitinib, a multi-targeted tyrosine kinase inhibitor, is frequently incorporated into the management of papillary thyroid carcinoma refractory to standard therapies. Although clinical trials are in progress, the mechanism of action in papillary thyroid carcinomas is not clear, especially regarding the effect on BRAF mutation. We investigated the effect of sunitinib on papillary thyroid carcinoma cells harboring RET/PTC rearrangement and BRAF mutation using TPC-1M, SNU-790, and B-cPAP cell lines. Cell growth of papillary thyroid cancer cells with RET/PTC rearrangement was effectively inhibited at low doses of sunitinib (IC50=0.658 µM), whereas that of BRAF mutated cells required higher doses. Immunoblotting revealed effective blocking of MEK/ERK pathway in RET/PTC rearrangement cells, but not in BRAF mutated cells. Cell cycle analysis showed G1 arrest in RET/PTC rearrangement cells. In vivo orthotopic thyroid cancer mouse model demonstrated statistically significant tumor growth inhibition by sunitinib in RET/PTC rearrangement cancer cells. We conclude that sunitinib effectively inhibits RET/PTC rearrangement cells but not BRAF mutated cells. These data suggest that sunitinib exerts its effect by inhibiting the upstream MAPK signaling cascade. These findings support the unsatisfactory treatment outcomes of sunitinib in many already ongoing clinical trials compared to other tyrosine kinase inhibitors. Clinical application of sunitinib should be directed accordingly.

Relationship between olfactory function and olfactory neuronal population in C57BL6 mice injected intraperitoneally with 3-methylindole.

OBJECTIVE: It is not known how many olfactory receptor neurons should be intact to maintain olfaction in mouse models treated with 3-methylindole. The aim of this study is to investigate the relationship between a simple olfactory test outcome and the olfactory neuronal population. STUDY DESIGN: Mouse model. SETTING: Animal laboratory of the Seoul National University Bundang Hospital. SUBJECTS AND METHODS: Olfactory dysfunction was induced by intraperitoneal injection of 3-methylindole in 38 six-week-old female C57BL6 mice. Olfactory function was evaluated by a food-finding test following 72-hour starvation. The olfactory neuronal population was quantified by olfactory marker protein (OMP) expression. RESULTS: The average time for finding food was 8.1 seconds in control mice. It was 13.4, 84.4, 90.1, and 111.4 seconds for mice injected with 100, 200, 300, and 400 µg/g of 3-methylindole, respectively. Harvesting the whole olfactory neuroepithelium, densitometric analysis showed significant decrease of OMP in the 300- and 400-µg/g groups as compared with controls (18.8% and 17.5% of relative density, respectively). In the olfactory bulb, there was a significant decrease of OMP in the 200-, 300-, and 400-µg/g groups (44.5%, 37.0%, and 9.0% of relative density, respectively). The food-finding time had a significant reverse correlation with the relative density of OMP both in the olfactory bulb and in the olfactory neuroepithelium. CONCLUSION: Our study showed that olfactory impairment was correlated with olfactory neuronal population in mice treated with 3-methylindole. The food-finding test would be a useful tool that could be easily performed without special training in the 3-methylindole-treated C57BL6 anosmic mouse model.

Transplantation of neural stem cells in anosmic mice.

OBJECTIVES: Treating olfactory dysfunction is a challenge for physicians. One of the therapeutic options could be transplantation of stem cells. In this study, neural stem cells were transplanted into anosmic mice. METHODS: Neural stem cells were generated from the olfactory bulb of green fluorescent protein (GFP)-transgenic C57BL6 mice. Anosmia were induced by injection of intraperitoneal 3-methylindole. The neural stem cells were transplanted transnasally on the next day. The olfactory function was evaluated by a food-finding test once a week. The olfactory neuroepithelium was harvested for histologic examination and protein analysis at 4 weeks. RESULTS: Twenty-five percent (6/24) of the control mice that were not transplanted with neural stem cells survived at 4 weeks while 67% (8/12) of the transplanted mice survived (P=0.029). The food finding test showed that the transplanted mice resumed finding food at 3 weeks while the control mice resumed finding food at 4 weeks. GFP-positive cells were observed in the olfactory neuroepithelium of the transplanted mice. Western blotting revealed that the olfactory marker protein expression was significantly lower in the control mice than that in the transplanted mice. CONCLUSION: This study demonstrated that improvement of mouse survival was achieved and recovery of olfactory function was promoted by transnasal transplantation of neural stem cells in the anosmic mouse model. These results indicate that stem cells might be one of the future modalities for treating olfactory impairment.

Role of OXA-23 and AdeABC efflux pump for acquiring carbapenem resistance in an Acinetobacter baumannii strain carrying the blaOXA-66 gene.

This study was performed to determine the mechanisms for acquiring carbapenem resistance in six clinical isolates of Acinetobacter baumannii. All isolates showed similar SmaI-macrorestriction patterns with less than 3 band differences by PFGE. The isolates showed a high level resistance (>32 mg/L) to both imipenem and meropenem by Etest. Phe-Arg-beta-naphthylamide lowered the MICs of carbapenems. Real-time PCR experiments showed that expression levels of the adeB gene in the six A. baumannii isolates were 10- to 40-times higher than those of imipenem-susceptible strains. Direct sequencing of PCR products showed that all isolates carried the bla(OXA-23) gene, which was preceded by ISAba1. The bla(OXA-23) probe hybridized with approximately 500-kb I-CeuI chromosomal fragments, but not with a plasmid. These findings suggest that overexpression of the AdeABC efflux pump as well as chromosome-borne OXA-23 may play a role in acquiring carbapenem resistance in our A. baumannii isolates.

In vivo selection of carbapenem-resistant Klebsiella pneumoniae by OmpK36 loss during meropenem treatment.

We recovered a carbapenem-resistant Klebsiella pneumoniae isolate H224 under in vivo meropenem selection pressure. Insertional inactivation of a major porin gene, ompK36, by IS5 element might play a role in acquiring carbapenem resistance in this strain harboring plasmid-borne DHA-1 AmpC beta-lactamase.

Overexpression of OgPAE1 from wild rice confers fungal resistance against Botrytis cinerea.

A full-length cDNA of the OgPAE1 gene encoding the alpha5 subunit of the 20S proteasome was isolated from wild rice (Oryza grandiglumis) treated by wounding or with a fungal elicitor. The deduced amino acid sequence of OgPAE1 comprises 237 amino acids (25.99 kDa), and shows 94.5% homology with Arabidopsis thaliana AtPAE1. Expression of OgPAE1 is regulated by defense-related signaling chemicals such as cantharidin, endothall and jasmonic acid. Overexpression of OgPAE1 in A. thaliana leads to resistance to the fungal pathogen Botrytis cinerea by lowering disease rate and size of necrotic lesions, and by less penetration and colonization of fungal hyphae. The results indicate that the 20S proteasome from wild rice is involved in the B. cinerea defense pathway via an as yet undetermined mechanism.

Identification of chicken nebulin isoforms of the 31-residue motifs and non-muscle nebulin.

Nebulin is a very large (M(r) 600-900kDa) actin-binding protein that is specific to skeletal muscle, and which is thought to act as a molecular template that regulates the length of sarcomere thin filaments. The 31-residue motif of nebulin contains a unique PEhXRVKXNQ consensus sequence. We have previously identified 11 different human nebulin isoforms of these 31-residue motifs. Here we present the identification of seven different isoforms (types II, III, IVa, IVb, V, VI, and X) of the 31-residue motifs in 15-day-old chicken embryo breast muscle. Isoform types II and III are also expressed in the brain, and type III is also detected in the heart, stomach, and liver. Chicken nebulin contains 11 copies of the 31-residue motif (R1a/b, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11), whereas human nebulin contains 13 copies. We confirmed the expression of nebulin in the heart, stomach, and brain in 15-day-old chicken embryos by immunofluorescence microscopy. The presence of nebulin in brain was further confirmed by in situ hybridization. These data suggest that there is even more diversity in nebulin isoforms than was previously known; this diversity likely contributes to the distinct actin filament architecture of different tissues.