Computational design of a thermolabile uracil-DNA glycosylase of Escherichia coli.

Polymerase chain reaction (PCR) is a powerful tool to diagnose infectious diseases. Uracil DNA glycosylase (UDG) is broadly used to remove carryover contamination in PCR. However, UDG can contribute to false negative results when not inactivated completely, leading to DNA degradation during the amplification step. In this study, we designed novel thermolabile UDG derivatives by supercomputing molecular dynamic simulations and residual network analysis. Based on enzyme activity analysis, thermolability, thermal stability, and biochemical experiments of Escherichia coli-derived UDG and 22 derivatives, we uncovered that the UDG D43A mutant eliminated the false negative problem, demonstrated high efficiency, and offered great benefit for use in PCR diagnosis. We further obtained structural and thermodynamic insights into the role of the D43A mutation, including perturbed protein structure near D43; weakened pairwise interactions of D43 with K42, N46, and R80; and decreased melting temperature and native fraction of the UDG D43A mutant compared with wild-type UDG.

The Effect of Home-based Daily Journal Writing in Korean Adolescents with Smartphone Addiction.

Despite the benefits of smartphones, many adverse effects have emerged. However, to date, there was no particular approach to treat or prevent smartphone addiction. The aim of this study was to evaluate the therapeutic effectiveness of a home-based daily journal of smartphone use (HDJ-S) in Korean adolescents. Three hundred thirty five middle school students participated in this study. The severity of smartphone addiction was measured using the Korean Smartphone Addiction Proneness Scale. The ability to control smartphone use was evaluated with the Motive Scale for Smartphone Regulation. We used the Parents' Concerns for Children's Smartphone Activities Scale to measure parental monitoring and supervision of adolescents' smartphone activities. The Korean Smartphone Addiction Proneness Scale classified subjects into high risk and non-high risk for smartphone addiction, according to total scores. Forty six participants (14%) were high risk for smartphone addiction. The high risk group performed the HDJ-S for two weeks, and the same scales were subsequently assessed. After performing the HDJ-S, the total scores of the Korean Smartphone Addiction Proneness Scale decreased significantly in the high risk group (P < 0.001). There was a significant increase in the total scores of the Parents' Concerns for Children's Smartphone Activities Scale in the high risk group between baseline and following two weeks of treatment (P < 0.05). The HDJ-S was effective for adolescents with smartphone addiction and increased the parents' concerns for their children's smartphone activities. We suggested that HDJ-S would be considered as a treatment and prevention for smartphone addiction.

Amorphous ITZO-Based Selector Device for Memristor Crossbar Array.

In the era of digital transformation, a memristor and memristive circuit can provide an advanced computer architecture that efficiently processes a vast quantity of data. With the unique characteristic of memristor, a memristive crossbar array has been utilized for realization of nonvolatile memory, logic-in-memory circuit, and neuromorphic system. However, the crossbar array architecture suffers from leakage of current, known as the sneak current, which causes a cross-talk interference problem between adjacent memristor devices, leading to an unavoidable operational error and high power consumption. Here, we present an amorphous In-Sn-Zn-O (a-ITZO) oxide semiconductor-based selector device to address the sneak current issue. The a-ITZO-selector device is realized with the back-to-back Schottky diode with nonlinear current-voltage (I-V) characteristics. Its nonlinearity is dependent on the oxygen plasma treatment process which can suppress the surface electron accumulation layer arising on the a-ITZO surface. The a-ITZO-selector device shows reliable characteristics against electrical stress and high temperature. In addition, the selector device allows for a stable read margin over 1 Mbit of memristor crossbar array. The findings may offer a feasible solution for the development of a high-density memristor crossbar array.

Coevolution underlies GPCR-G protein selectivity and functionality.

G protein-coupled receptors (GPCRs) regulate diverse physiological events, which makes them as the major targets for many approved drugs. G proteins are downstream molecules that receive signals from GPCRs and trigger cell responses. The GPCR-G protein selectivity mechanism on how they properly and timely interact is still unclear. Here, we analyzed model GPCRs (i.e. HTR, DAR) and Gα proteins with a coevolutionary tool, statistical coupling analysis. The results suggested that 5-hydroxytryptamine receptors and dopamine receptors have common conserved and coevolved residues. The Gα protein also have conserved and coevolved residues. These coevolved residues were implicated in the molecular functions of the analyzed proteins. We also found specific coevolving pairs related to the selectivity between GPCR and G protein were identified. We propose that these results would contribute to better understandings of not only the functional residues of GPCRs and Gα proteins but also GPCR-G protein selectivity mechanisms.

Mass spectrometry-based metabolomics in hair from current and former patients with methamphetamine use disorder.

Drug use disorder, a chronic and relapsing mental disorder, is primarily diagnosed via self-reports of drug-seeking behavioral and psychological conditions, accompanied by psychiatric assessment. Therefore, the identification of peripheral biomarkers that reflect pathological changes caused by such disorders is essential for improving treatment monitoring. Hair possesses great potential as a metabolomic sample for monitoring chronic diseases. This study aimed to investigate metabolic alterations in hair to elucidate a suitable treatment modality for methamphetamine (MA) use disorder. Consequently, both targeted and untargeted metabolomics analyses were performed via mass spectrometry on hair samples obtained from current and former patients with MA use disorder. Healthy subjects (HS), current (CP), and former (FP) patients with this disorder were selected based on psychiatric diagnosis and screening the concentrations of MA in hair. The drug abuse screening questionnaire scores did not differentiate between CP and FP. Moreover, according to both targeted and untargeted metabolomics, clustering was not observed among all three groups. Nevertheless, a model of partial least squares-discriminant analysis was established between HS and CP based on seven metabolites derived from the targeted metabolomics results. Thus, this study demonstrates the promising potential of hair metabolomes for monitoring recovery from drug use disorders in clinical practice.

Solution-Processed Organic and Oxide Hybrid CMOS Inverter for Low Cost Electronic Circuits.

We demonstrated an organic and oxide hybrid CMOS inverter with the solution-processed semiconductor and source/drain electrodes. For the solution-processed n- and p-type semiconductor, InGaZnO solution and TIPS-pentacene/PαMS blend were spin-coated respectively while Silver ink and PEDOT:PSS solution were drop-casted with the help of the bank to serve as source/drain electrodes. The InGaZnO and the TIPS-pentacene transistors show typical n- and p-type transistor operations with low off-current. Based on the combination of the solution-processed n- and p-type transistors, full-swing characteristic curve with low static current of the hybrid CMOS were obtained.

Characteristics of Korean patients with methamphetamine use disorder based on the quantitative analysis of methamphetamine and amphetamine in hair.

Methamphetamine (MA) is a highly addictive central nervous system stimulant. MA use disorder is characterized by a chronic, relapsing brain disease that is enhanced by a dynamic process of repeated use and withdrawal. The analysis of MA and its metabolite, amphetamine (AM), in hair is routinely performed in forensic laboratories for illegal MA use determination. However, few studies regarding the clinical application of hair analysis have been conducted to monitor the treatment of MA use disorder. Herein, the characteristics of Korean patients with MA use disorder were investigated based on drug abuse screening instruments and quantitative analysis of MA and AM in hair. A HPLC-MS/MS method for the quantification of MA and AM in hair was validated and clinically applied to healthy subjects (HS, n = 30, male) as well as current (CP, n = 33, male) and former (FP, n = 22, male) MA use disorder patients. The validation results of the hair analysis method showed high selectivity, accuracy, and precision with acceptable linearity within the calibration range (0.05-5.0 ng/mg). The limit of detection (LOD) and limit of quantification for both MA and AM were 0.05 ng/mg. The concentrations of MA and AM ranged from ≤ LOD to 166 ng/mg and from not detected (ND) to 9.15 ng/mg in the CP group and from ND to 6.14 ng/mg and from ND to 0.32 ng/mg in the FP group, respectively. No correlation was observed between the hair MA concentrations and the NIDA-modified ASSIST, DUDID extended, or DAST scores in both groups. The hair MA concentrations showed advantages for differentiating the CP and FP groups compared with the scores provided by the above-mentioned drug abuse screening instruments.

A 10 nV/rt Hz noise level 32-channel neural impedance sensing ASIC for local activation imaging on nerve section.

A 10 nV/rt Hz noise level 32-channel neural impedance sensing ASIC is presented for the application of local activation imaging in nerve section. It is increasingly known that the monitoring and control of nerve signals can improve physical and mental health. Major nerves, such as the vagus nerve and the sciatic nerve, consist of a bundle of fascicles. Therefore, to accurately control a particular application without any side effects, we need to know exactly which fascicle was activated. The only way to find locally activated fascicle is to use electrical impedance tomography (EIT). The ASIC to be introduced is designed for neural EIT applications. A neural impedance sensing ASIC was implemented using CMOS 180-nm process technology. The integrated input referred noise was calculated to be 0.46 µVrms (noise floor 10.3 nVrms/rt Hz) in the measured noise spectrum. At an input of 80 mV, the squared correlation coefficient for linear regression was 0.99998. The amplification gain uniformity of 32 channels was in the range of + 0.23% and - 0.29%. Using the resistor phantom, the simplest model of nerve, it was verified that a single readout channel could detect a signal-to- noise ratio of 75.6 dB or more. Through the reservoir phantom, real-time EIT images were reconstructed at a rate of 8.3 frames per second. The developed ASIC has been applied to in vivo experiments with rat sciatic nerves, and signal processing is currently underway to obtain activated nerve cross-sectional images. The developed ASIC was also applied to in-vivo experiments with rat sciatic nerves, and signal processing is currently underway to obtain locally activated nerve cross-sectional images.

Fermented rice bran downregulates MITF expression and leads to inhibition of alpha-MSH-induced melanogenesis in B16F1 melanoma.

Rice bran contains various polyphenolic compounds with anti-oxidative activities, and it has long been known to inhibit melanogenesis, but the inhibition mechanism has not been fully elucidated. Cofermentation of rice bran with Lactobacillus rhamnosus and Saccharomyces cerevisiae significantly reduced the cytotoxicity of the resulting extract to B16F1 melanoma cells. Marked reduction of alpha-melanocyte stimulating hormone (MSH) induced melanin synthesis was also observed upon treatment with fermented rice bran extract but it had no direct inhibitory effect on tyrosinase activity, while the intracellular tyrosinase activity was reduced by the extract. This result was further confirmed by an immunoblot assay measuring the level of tyrosinase protein. In addition, the expression of microphthalmia-associated transcription factor (MITF), a key regulator of melanogenesis, was significantly decreased by the extract. All together, the fermented rice bran extracts showed an inhibitory effect on melanogenesis through downregulation of MITF, along with reduced cytotoxicity.

Anti-aging effect of rice wine in cultured human fibroblasts and keratinocytes.

The application of rice wine on skin is known to have beneficial effects such as enhancement of the skin barrier function and skin whitening. In this study, we focused on examination of the anti-aging effects of rice wine. The treatment of fibroblasts with rice wine in vitro increased the expression of procollagen and laminin-5, a key basement membrane component in cultured human fibroblasts. Rice wine significantly reduced the expression of UV-induced matrix metalloproteinase-1 (MMP-1) in a dose-dependent manner in both cultured human fibroblasts and keratinocytes. In addition, treatment with rice wine decreased UV-induced tumor necrosis factor-alpha (TNF-alpha) production in human keratinocytes. An in vivo study using hairless mice showed that topical application of rice wine protected mouse skin from photoaging. Thus, we suggest that rice wine may have potential as an effective agent for the prevention and treatment of UV-induced skin aging.

Monitoring of Leuconostoc mesenteroides DRC starter in fermented vegetable by random integration of chloramphenicol acetyltransferase gene.

In 2004, Leuconostoc mesenteroides DRC was first used as a starter culture for achieving higher organoleptic effects in Korean kimchi manufacture. For a better understanding of starter growth in a mixed culture system, and for predicting starter predominance in kimchi, a monitoring system for the starter was established. The chloramphenicol resistance marker gene (cat) was randomly integrated into chromosomal DNA of L. mesenteroides DRC using a viral transposon and transposase. The DRC mutant, tDRC2, had a similar growth pattern to the host strain, with no major alteration in phenotypic characteristics. The mutant strain was inoculated into real kimchi, and monitoring of the starter population was successfully achieved. The overall predominance of Leuconostoc in kimchi inoculated with DRC followed the general growth pattern of this genus during kimchi fermentation. Our results also demonstrate the competitive ability of the DRC starter against Leuconostoc from natural flora, maintaining its predominance above 88% during the whole fermentation period. Based on this experiment, the random gene integration method using a transposon was shown to be of utility in transferring any commercial starter into a selectable and monitorable strain for simulation purposes.

New approaches to pathogenic gene function discovery with human squamous cell cervical carcinoma by gene ontology.

PURPOSE: This study utilized mRNA differential display and the Gene Ontology (GO) analysis to characterize the multiple interactions of a number of genes with gene expression profile involved in squamous cell cervical carcinoma. METHODS: mRNA differential displays were used to identify potential transcripts that were differentially expressed between cervix cancers of 13 patients (invasive cancer stages Ib-IIb) and universal reference RNAs comprised of 17 different normal cervixes. Aberrant bands were excised and used to make cDNA, which was sequenced. DNA sequences were compared to other nucleic acids in the NCBR database for homology. Transcript expression was verified in select samples using RT-PCR and North blotting. The specific functions were correlated with gene expression patterns via gene ontology. RESULTS: Fifty-eight genes were up- or down-regulated above 2-fold and organized into reciprocally dependent sub-function sets depending on the cervical cancer pathway. The GO analysis showed that squamous cell cervical carcinogenesis underwent complete up-regulation of cell cycle, transport, epidermal differentiation, protein biosynthesis, and RNA metabolism. Also, genes belonging to protein metabolism and catabolism activity were significantly up-regulated. In contrast, significant down-regulation was shown in muscle development, cell adhesion, and damaged DNA binding activity. CONCLUSION: The GO analysis can overcome the complexity of the gene expression profile of the squamous cell cervical carcinoma-associated pathway and identify several cancer-specific cellular processes as well as genes of unknown function. Also, GO analysis can serve as a powerful basis for a molecular classification of carcinogenesis.