Characterization of Ribose-5-Phosphate Isomerase B from Newly Isolated Strain Ochrobactrum sp. CSL1 Producing L-Rhamnulose from L-Rhamnose

( Min Shen ),( Xin Ju ),( Xinqi Xu ),( Xuemei Yao ),( Liangzhi Li ),( Jiajia Chen ),( Cuiying Hu ),( Jiaolong Fu ),( Lishi Yan ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.7

In this study, we attempted to find new and efficient microbial enzymes for producing rare sugars. A ribose-5-phosphate isomerase B (OsRpiB) was cloned, overexpressed, and preliminarily purified successfully from a newly screened Ochrobactrum sp. CSL1, which could catalyze the isomerization reaction of rare sugars. A study of its substrate specificity showed that the cloned isomerase (OsRpiB) could effectively catalyze the conversion of L-rhamnose to L-rhamnulose, which was unconventional for RpiB. The optimal reaction conditions (50oC, pH 8.0, and 1 mM Ca²⁺) were obtained to maximize the potential of OsRpiB in preparing L-rhamnulose. The catalytic properties of OsRpiB, including K_m, K_cat, and catalytic efficiency (K_cat/K_m), were determined as 43.47 mM, 129.4 sec^-1, and 2.98 mM/sec. The highest conversion rate of L-rhamnose under the optimized conditions by OsRpiB could reach 26% after 4.5 h. To the best of our knowledge, this is the first successful attempt of the novel biotransformation of L-rhamnose to L-rhamnulose by OsRpiB biocatalysis.

Ascorbic Acid Alleviates Pancreatic Damage Induced by Dibutyltin Dichloride (DBTC) in Rats

Xin-Liang Lu,Yan-Hua Song,Yan-Biao Fu,Jian-Min Si,Ke-Da Qian 연세대학교의과대학 2007 Yonsei medical journal Vol.48 No.6

Purpose: Because previous studies have reported depleted antioxidant capacity in patients with chronic pancreatitis (CP), prevention of free radical production has gained importance in antifibrotic treatment strategies for CP. The aim of this study was to investigate the effects of ascorbic acid on oxidative capacity and pancreatic damage in experimental CP. Materials and Methods: CP was induced in male Sprague-Dawley rats by infusion of dibutyltin dichloride (DBTC) into the tail vein. Ascorbic acid was given intraperitoneally at a daily dose of 10mg/kg body weight. The treatment groups were as follows: group 1, DBTC plus intraperitoneal physiologic saline; group 2, DBTC plus intraperitoneal ascorbic acid; group 3, solvent plus intraperitoneal physiologic saline; group 4, no operation plus intraperitoneal physiologic saline. Each group contained 15 animals. Treatment was started after CP was established. After 4 weeks of treatment, serum hyaluronic acid and laminin levels were determined by radioimmunoassay, pancreatic tissue oxidative stress was analyzed, and the degree of pancreatic damage was determined. Results: Ascorbic acid treatment markedly increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) concentrations in pancreatic tissue (p<0.01 for both). Significant serum hyaluronic acid and laminin reductions were observed in group 2 as compared with group 1 (p<0.05). However, the serum hyaluronic acid and laminin levels remained elevated when compared with those of groups 3 and 4 (p<0.05). Histopathologic scores were also lower in animals with CP that underwent ascorbic acid-treatment (p<0.05). Conclusion: Ascorbic acid treatment alleviated the degree of oxidative stress and pancreatic damage in rat CP. Antioxidant treatment might be considered a potential option to improve the pathologic process in CP.

Risk Factors for Anxiety in Major Depressive Disorder Patients

Li-Min Xin,Lin Chen,Zhen-Peng Ji,Suo-Yuan Zhang,Jun Wang,Yan-Hong Liu,Da-Fang Chen,Fu-De Yang,Gang Wang,Yi-Ru Fang,Zheng Lu,Hai-Chen Yang,Jian Hu,Zhi-Yu Chen,Yi Huang,Jing Sun,Xiao-Ping Wang,Hui-Chun 대한정신약물학회 2015 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.13 No.3

Objective: To analyze the sociodemographic and clinical factors related to anxiety in patients with major depressive disorder (MDD). Methods: This study involved a secondary analysis of data obtained from the Diagnostic Assessment Service for People with Bipolar Disorders in China (DASP), which was initiated by the Chinese Society of Psychiatry (CSP) and conducted from September 1, 2010 to February 28, 2011. Based on the presence or absence of anxiety-related characteristics, 1,178 MDD patients were classified as suffering from anxious depression (n=915) or non-anxious depression (n=263), respectively. Results: Compared with the non-anxious group, the anxious-depression group had an older age at onset (t=−4.39, p<0.001), were older (t=−4.69, p<0.001), reported more lifetime depressive episodes (z=−3.24, p=0.001), were more likely to experience seasonal depressive episodes (χ2=6.896, p=0.009) and depressive episodes following stressful life events (χ2=59.350, p <0.001), and were more likely to have a family history of psychiatric disorders (χ2=6.091, p=0.014). Their positive and total scores on the Mood Disorder Questionnaire (MDQ) and the 32-item Hypomania Checklist (HCL-32) (p<0.05) were also lower. The logistic regression analysis indicated that age (odds ratio [OR]=1.03, p<0.001), a lower total MDQ score (OR=0.94, p=0.011), depressive episodes following stressful life events (OR=3.04, p<0.001), and seasonal depressive episodes (OR=1.75, p=0.039) were significantly associated with anxious depression. Conclusion: These findings indicate that older age, fewer subclinical bipolar features, an increased number of depressive episodes following stressful life events, and seasonal depressive episodes may be risk factors for anxiety-related characteristics in patients with MDD.

Cytotoxic Constituents from Solanum Lyratum

Li-Xin Sun,Wen-wei Fu,Jing Ren,Liang Xu,Kai-Shun Bi,Min-Wei Wang 대한약학회 2006 Archives of Pharmacal Research Vol.29 No.2

Activity-guided fractionation of the ethanol extract of the whole plant from Solanum lyratum resulted in the isolation of a new pregnane derivative glycoside, 16-dehydropregnenolone 3-O- α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosid uronic acid (2), as well as other six known compounds: 16-dehydropregnenolone (1), allopregenolone (3), protocatechuic acid (4), vanillic acid (5), caffeic acid (6), and scopoletin (7). The structures of the isolated compounds were elucidated on the basis of their spectral data and chemical evidences. Compounds 1, 3, 4 were isolated for the first time from this plant. Cytotoxic activities of the isolated compounds were evaluated. Compound 1 exhibited significant cytotoxic activity against A375-S2, HeLa, SGC-7901, and Bel-7402 with IC50 values of 13.1 ± 0.9, 21.5 ± 1.0, 40.2 ± 0.7, and 49.8 ± 1.2 µg/mL, respectively.

Cytotoxic Constituents from Solanum Lyratum

Sun Li-Xin,Fu Wen-wei,Ren Jing,Xu Liang,Bi Kai-Shun,Wang Min-Wei The Pharmaceutical Society of Korea 2006 Archives of Pharmacal Research Vol.29 No.2

Activity-guided fractionation of the ethanol extract of the whole plant from Solanum lyratum resulted in the isolation of a new pregnane derivative glycoside, 16-dehydropregnenolone 3-O-${\alpha}$-L-rhamnopyranosyl-($1{\to}2$)-${\beta}$-D-glucopyranosid uronic acid (2), as well as other six known compounds: 16-dehydropregnenolone (1), allopregenolone (3), protocatechuic acid (4), vanillic acid (5), caffeic acid (6), and scopoletin (7). The structures of the isolated compounds were elucidated on the basis of their spectral data and chemical evidences. Compounds 1, 3, 4 were isolated for the first time from this plant. Cytotoxic activities of the isolated compounds were evaluated. Compound 1 exhibited significant cytotoxic activity against A375-S2, HeLa, SGC-7901, and Bel-7402 with $IC_{50}$ values of $13.1{\pm}0.9,\;21.5{\pm}1.0,\;40.2{\pm}0.7$, and $49.8{\pm}1.2\;{\mu}g/mL$, respectively.

A Campus Community-based Mobility Model for Routing in Opportunistic Networks

( Daru Pan ),( Min Fu ),( Jiajia Sun ),( Xin Zou ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.3

Mobility models are invaluable for determining the performance of routing protocols in opportunistic networks. The movement of nodes has a significant influence on the topological structure and data transmission in networks. In this paper, we propose a new mobility model called the campus-based community mobility model (CBCNM) that closely reflects the daily life pattern of students on a real campus. Consequent on a discovery that the pause time of nodes in their community follows a power law distribution, instead of a classical exponential distribution, we abstract the semi-Markov model from the movement of the campus nodes and analyze its rationality. Then, using the semi-Markov algorithm to switch the movement of the nodes between communities, we infer the steady-state probability of node distribution at random time points. We verified the proposed CBCNM via numerical simulations and compared all the parameters with real data in several aspects, including the nodes` contact and inter-contact times. The results obtained indicate that the CBCNM is highly adaptive to an actual campus scenario. Further, the model is shown to have better data transmission network performance than conventional models under various routing strategies.

Effect of Mechanical Alloying and Sintering Behavior on the Microstructure and Properties of NbMoTaWRe Refractory High Entropy Alloy

Tao Gu,Li‑Min Wang,Qiang Hu,Xiu‑Bing Liang,Dong‑Xing Fu,Yong‑Xiong Chen,Xin‑Ming Zhao,Yan‑Wei Sheng 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.11

An equiatomic refractory high-entropy alloy (RHEA) NbMoTaWRe is prepared by mechanical alloying (MA) and sparkplasma sintering (SPS). The effects of mechanical alloying and sintering behaviors on the microstructure and propertiesof the RHEA are investigated. After ball-milling for 30 h, the metastable and supersaturated MA powders with the bodycenteredcubic (BCC) structure are obtained. Then, the MA powders are sintered using the SPS method under the sinteringtemperature range of 1700–1900 °C, and the C atoms and WC introduced by the MA process reacts with the metastable andsupersaturated Ta/Nb phase of the MA powers to form the face-centered cubic (FCC) structure (Nb, Ta)C particles alongthe BCC matrix boundaries during the SPS process. The NbMoTaWRe alloy sintered at 1800 °C consisted of BCC matrixand FCC-type (Nb, Ta)C particles has high compactness (porosity fraction is 0.32%), fracture strength (2630 MPa), plasticstrain (6.82%), and hardness (992 ± 20 HV). These excellent properties of this RHEA are mainly attributed to the combinationof multi-effects, including sintering densification, grain refinement strengthening from the refined sizes (3.80 μm) BCCmatrix, precipitation strengthening from the (Nb, Ta)C particles, solid solution strengthening from multi-principal elementsand interstitial solid solution strengthening from C atoms dissolving into BCC matrix.

Expression of IER3 in Primary Hepatocarcinoma: Correlation with Clinicopathological Parameters

Liu, Zhong,Wang, Xin-Mei,Jia, Tong-Fu,Zhai, Yi,Sun, Ling-Yan,Cheng, Yu-Ping,Zhang, Yue-Min,Liu, Shi-Hai,Liang, Jun Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.2

Background: Studies indicate the immediate early response gene 3 (IER3) is involved in many biological processes. Recently, it was discovered that IER3 plays an important role in tumorigenesis and tumor progression. Thus it may be a valuable biomarker in tumor. This study was designed to investigate the expression status of IER3 in primary hepatocarcinoma (PHC) and correlation with clinicopathological parameters. Materials and Methods: Real-time PCR was performed to evaluate the expression levels of IER3 in 62 pathologically diagnosed human PHC specimens. Results: A statistically significant association was disclosed between the expression of IER3 and P53 mutant protein (short for P53), Ki-67, EGFR and the biggest diameter, differentiation grade of tumor. Conclusions: This work is the first to shed light on the potential clinical usefulness of IER3, as an efficient tumor biomarker in PHC.

The Role of Ribose on Oxidative Stress During Hypoxic Exercise: A Pilot Study

Seifert, John G.,Subudhi, Andrew W.,Fu, Min-Xin,Riska, Karen L.,John, Jeff C.,Shecterle, Linda M.,Cyr, John A. St. The Korean Society of Food Science and Nutrition 2009 Journal of medicinal food Vol.12 No.3

Oxygen free radicals are produced during stress, are unstable, and potentially interact with other cellular components or molecules. This reactivity can influence cellular function, including a prolongation in tissue recovery following exercise. We tested the effect of ribose (d-ribose), a pentose carbohydrate, in a double-blinded, crossover study on markers of free radical production during hypoxic exercise. Seven healthy volunteers cycled at their lactate threshold for 25 minutes while inhaling 16% $O_2$ with a subsequent 60-minute resting period at room air. Subjects ingested either placebo or 7 g of ribose in 250mL of water before and after the exercise session. Urinary malondialdehyde (MDA) and plasma reduced glutathione levels increased significantly during placebo ingestion ($0.2\;{\pm}\;0.03\;{\mu}M/mg$ and $0.26\;{\pm}\;0.29\;{\mu}M$, respectively) but were lower with ribose supplementation ($0.04\;{\pm}\;0.03\;{\mu}M/mg$ and $0.38\;{\pm}\;0.29\;{\mu}M$, respectively; P < .05). Uric acid levels were similar between groups (ribose vs. placebo, $4.55\;{\pm}\;0.06\;mg/dL$ vs. $4.67\;{\pm}\;0.06\;mg/dL$). Ribose demonstrated a beneficial trend in lower MDA and reduced glutathione levels during hypoxic stress.

The Role of Ribose on Oxidative Stress During Hypoxic Exercise: A Pilot Study

John G. Seifert,Andrew W. Subudhi,Min-Xin Fu,Karen L. Riska,Jeff C. John,Linda M. Shecterle,John A. St. Cyr 한국식품영양과학회 2009 Journal of medicinal food Vol.12 No.3

Oxygen free radicals are produced during stress, are unstable, and potentially interact with other cellular components or molecules. This reactivity can influence cellular function, including a prolongation in tissue recovery following exercise. We tested the effect of ribose (d-ribose), a pentose carbohydrate, in a double-blinded, crossover study on markers of free radical production during hypoxic exercise. Seven healthy volunteers cycled at their lactate threshold for 25 minutes while inhaling 16% O2 with a subsequent 60-minute resting period at room air. Subjects ingested either placebo or 7g of ribose in 250mL of water before and after the exercise session. Urinary malondialdehyde (MDA) and plasma reduced glutathione levels increased significantly during placebo ingestion (0.2±0.03nM/mg and 0.26±0.29μM, respectively) but were lower with ribose supplementation (0.04±0.03nM/mg and 0.38±0.29μM, respectively; P<.05). Uric acid levels were similar between groups (ribose vs. placebo, 4.55±0.06mg/dL vs. 4.67±0.06mg/dL). Ribose demonstrated a beneficial trend in lower MDA and reduced glutathione levels during hypoxic stress.