Mononuclear nonheme iron(iv)–oxo and manganese(iv)–oxo complexes in oxidation reactions: experimental results prove theoretical prediction

Chen, Junying,Cho, Kyung-Bin,Lee, Yong-Min,Kwon, Yoon Hye,Nam, Wonwoo The Royal Society of Chemistry 2015 Chemical communications Vol.51 No.66

<▼1><P>The HAT and OAT reactivities of Fe<SUP>IV</SUP>O and Mn<SUP>IV</SUP>O species with the N4Py ligand are compared both theoretically and experimentally and the reactivity of Fe<SUP>IV</SUP>O is found to be higher.</P></▼1><▼2><P>Reactivities of mononuclear nonheme iron(iv)–oxo and manganese(iv)–oxo complexes bearing a pentadentate N4Py ligand, [M<SUP>IV</SUP>O(N4Py)]<SUP>2+</SUP> (M = Fe and Mn), are compared in hydrogen atom transfer (HAT) and oxygen atom transfer (OAT) reactions; theoretical and experimental results show that Fe<SUP>IV</SUP>O is more reactive than Mn<SUP>IV</SUP>O. The latter is shown to react through excited state reactivity (ESR).</P></▼2>

Tuning the reactivity of mononuclear nonheme manganese( <small>IV</small> )-oxo complexes by triflic acid

Chen, Junying,Yoon, Heejung,Lee, Yong-Min,Seo, Mi Sook,Sarangi, Ritimukta,Fukuzumi, Shunichi,Nam, Wonwoo Royal Society of Chemistry 2015 Chemical Science Vol.6 No.6

<▼1><P>Binding of two HOTf molecules to Mn<SUP>IV</SUP>(O) species resulted in contrasting effects on the reactivities in oxygen atom transfer and H-atom transfer reactions.</P></▼1><▼2><P>Triflic acid (HOTf)-bound nonheme Mn(<SMALL>IV</SMALL>)-oxo complexes, [(L)Mn<SUP>IV</SUP>(O)]<SUP>2+</SUP>–(HOTf)<SUB>2</SUB> (L = N4Py and Bn-TPEN; N4Py = <I>N</I>,<I>N</I>-bis(2-pyridylmethyl)-<I>N</I>-bis(2-pyridyl)methylamine and Bn-TPEN = <I>N</I>-benzyl-<I>N</I>,<I>N</I>′,<I>N</I>′-tris(2-pyridylmethyl)ethane-1,2-diamine), were synthesized by adding HOTf to the solutions of the [(L)Mn<SUP>IV</SUP>(O)]<SUP>2+</SUP> complexes and were characterized by various spectroscopies. The one-electron reduction potentials of the Mn<SUP>IV</SUP>(O) complexes exhibited a significant positive shift upon binding of HOTf. The driving force dependences of electron transfer (ET) from electron donors to the Mn<SUP>IV</SUP>(O) and Mn<SUP>IV</SUP>(O)–(HOTf)<SUB>2</SUB> complexes were examined and evaluated in light of the Marcus theory of ET to determine the reorganization energies of ET. The smaller reorganization energies and much more positive reduction potentials of the [(L)Mn<SUP>IV</SUP>(O)]<SUP>2+</SUP>–(HOTf)<SUB>2</SUB> complexes resulted in greatly enhanced oxidation capacity towards one-electron reductants and <I>para</I>-X-substituted-thioanisoles. The reactivities of the Mn(<SMALL>IV</SMALL>)-oxo complexes were markedly enhanced by binding of HOTf, such as a 6.4 × 10<SUP>5</SUP>-fold increase in the oxygen atom transfer (OAT) reaction (<I>i.e.</I>, sulfoxidation). Such a remarkable acceleration in the OAT reaction results from the enhancement of ET from <I>para</I>-X-substituted-thioanisoles to the Mn<SUP>IV</SUP>(O) complexes as revealed by the unified ET driving force dependence of the rate constants of OAT and ET reactions of [(L)Mn<SUP>IV</SUP>(O)]<SUP>2+</SUP>–(HOTf)<SUB>2</SUB>. In contrast, deceleration was observed in the rate of H-atom transfer (HAT) reaction of [(L)Mn<SUP>IV</SUP>(O)]<SUP>2+</SUP>–(HOTf)<SUB>2</SUB> complexes with 1,4-cyclohexadiene as compared with those of the [(L)Mn<SUP>IV</SUP>(O)]<SUP>2+</SUP> complexes. Thus, the binding of two HOTf molecules to the Mn<SUP>IV</SUP>(O) moiety resulted in remarkable acceleration of the ET rate when the ET is thermodynamically feasible. When the ET reaction is highly endergonic, the rate of the HAT reaction is decelerated due to the steric effect of the counter anion of HOTf.</P></▼2>

A Mononuclear Non-Heme Manganese(IV)–Oxo Complex Binding Redox-Inactive Metal Ions

Chen, Junying,Lee, Yong-Min,Davis, Katherine M.,Wu, Xiujuan,Seo, Mi Sook,Cho, Kyung-Bin,Yoon, Heejung,Park, Young Jun,Fukuzumi, Shunichi,Pushkar, Yulia N.,Nam, Wonwoo American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.17

<P>Redox-inactive metal ions play pivotal roles in regulating the reactivities of high-valent metal–oxo species in a variety of enzymatic and chemical reactions. A mononuclear non-heme Mn(IV)–oxo complex bearing a pentadentate N<SUB>5</SUB> ligand has been synthesized and used in the synthesis of a Mn(IV)–oxo complex binding scandium ions. The Mn(IV)–oxo complexes were characterized with various spectroscopic methods. The reactivities of the Mn(IV)–oxo complex are markedly influenced by binding of Sc<SUP>3+</SUP> ions in oxidation reactions, such as a ∼2200-fold increase in the rate of oxidation of thioanisole (i.e., oxygen atom transfer) but a ∼180-fold decrease in the rate of C–H bond activation of 1,4-cyclohexadiene (i.e., hydrogen atom transfer). The present results provide the first example of a non-heme Mn(IV)–oxo complex binding redox-inactive metal ions that shows a contrasting effect of the redox-inactive metal ions on the reactivities of metal–oxo species in the oxygen atom transfer and hydrogen atom transfer reactions.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-17/ja312113p/production/images/medium/ja-2012-12113p_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja312113p'>ACS Electronic Supporting Info</A></P>

Bacterial Community Structure and Function Shift in Rhizosphere Soil of Tobacco Plants Infected by Meloidogyne incognita

Wenjie Tong(Wenjie Tong),Junying Li(Junying Li),Wenfeng Cong(Wenfeng Cong),Cuiping Zhang(Cuiping Zhang),Zhaoli Xu(Zhaoli Xu),Xiaolong Chen(Xiaolong Chen),Min Yang(Min Yang),Jiani Liu(Jiani Liu),Lei Yu 한국식물병리학회 2022 Plant Pathology Journal Vol.38 No.6

Root-knot nematode disease is a widespread and catastrophic disease of tobacco. However, little is known about the relationship between rhizosphere bacterial community and root-knot nematode disease. This study used 16S rRNA gene sequencing and PICRUSt to assess bacterial community structure and function changes in rhizosphere soil from Meloidogyne incognita-infected tobacco plants. We studied the rhizosphere bacterial community structure of M. incognita-infected and uninfected tobacco plants through a paired comparison design in two regions of tobacco planting area, Yuxi and Jiuxiang of Yunnan Province, southwest China. According to the findings, M. incognita infection can alter the bacterial population in the soil. Uninfested soil has more operational taxonomic unit numbers and richness than infested soil. Principal Coordinate Analysis revealed clear separations between bacterial communities from infested and uninfested soil, indicating that different infection conditions resulted in significantly different bacterial community structures in soils. Firmicutes was prevalent in infested soil, but Chloroflexi and Acidobacteria were prevalent in uninfested soil. Sphingomonas, Streptomyces, and Bradyrhizobium were the dominant bacteria genera, and their abundance were higher in infested soil. By PICRUSt analysis, some metabolism-related functions and signal transduction functions of the rhizosphere bacterial community in the M. incognita infection-tobacco plants had a higher relative abundance than those uninfected. As a result, rhizosphere soils from tobacco plants infected with M. incognita showed considerable bacterial community structure and function alterations.

Incorporating heuristic information into ant colony optimization for epistasis detection

Junliang Shang,Junying Zhang,Xiujuan Lei,Yuanyuan Zhang,Baodi Chen 한국유전학회 2012 Genes & Genomics Vol.34 No.3

Epistasis has been receiving increasing attention in understanding the mechanism underlying susceptibility to complex diseases. Though many works have been done for epistasis detection, genome-wide association study remains a challenging task: it makes the search space excessively huge while solution quality is excessively demanded. In this study, we introduce an ant colony optimization based algorithm,AntMiner, by incorporating heuristic information into ant-decision rules. The heuristic information is used to direct ants in the search process for improving computational efficiency and solution accuracy. During iterations, chi-squared test is conducted to measure the association between an interaction and the phenotype. At the completion of the iteration process, statistically significant epistatic interactions are ordered and then screened by a post-procedure. Experiments of AntMiner and its comparison with existing algorithms epiMODE, TEAM and AntEpiSeeker are performed on both simulation data sets and real age-related macular degeneration data set, under the criteria of detection power and sensitivity. Results demonstrate that AntMiner is promising for epistasis detection. In terms of detection power, AntMiner performs best among all the other algorithms on all cases regardless of epistasis models and single nucleotide polymorphism size; compared with AntEpiSeeker, AntMiner can obtain better detection power but with less ants and iterations. In terms of sensitivity, AntMiner is better than AntEpiSeeker in detecting epistasis models displaying marginal effects but it has moderate sensitivity on epistasis models displaying no marginal effects. The study may provide clues on heuristics for further epistasis detection. The software package is available online at https://sourceforge.net/projects/antminer/files/.

Optimization of basic magenta adsorption onto Fe/Cu nanocomposites synthesized by sweet potato leaf extract using response surface methodology

Yuanyuan Niu,Ruijuan Jia,Chenglin Liu,Xiuli Han,Chun Chang,Junying Chen 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.8

Green synthesis of metal nanoparticles using plant extracts as an effective bio-reducing reagent has attracted considerable attention. Fe/Cu nanocomposites synthesized by extracts of sweet potato leaves served to remove basic magenta (BM) from aqueous solution. The adsorption operation conditions of BM on Fe/Cu nanocomposites were optimum by Box-Behnken design (BBD) model of response surface methodology (RSM). The adsorption equilibrium data were well described by the Sips and Redlich-Peterson models. The thermodynamic studies showed that the adsorption process was endothermic and spontaneous. The maximum adsorption capacity from the Sips model was 235.92mg/g at 298 K, which indicated that Fe/Cu nanocomposites had potential application in wastewater treatment. As indicated by pseudo-second order kinetics model, the adsorption of BM onto Fe/Cu nanocomposites could be achieved through the complexation, H-bonding, - adsorbate-adsorbent interaction, and electrostatic interaction at different pH values

MCT2 overexpression promotes recovery of cognitive function by increasing mitochondrial biogenesis in a rat model of stroke

Xiaorong Yu,Rui Zhang,Cunsheng Wei,Yuanyuan Gao,Yanhua Yu,Lin Wang,Junying Jiang,Xuemei Zhang,Junrong Li,Xuemei Chen 한국통합생물학회 2021 Animal cells and systems Vol.25 No.2

Monocarboxylate transporter 2 (MCT2) is the predominant monocarboxylate transporter expressed by neurons. MCT2 plays an important role in brain energy metabolism. Stroke survivors are at high risk of cognitive impairment. We reported previously that stroke-induced cognitive impairment was related to impaired energy metabolism. In the present study, we report that cognitive function was impaired after stroke in rats. We found that MCT2 expression, but not that of MCT1 or MCT4, was markedly decreased in the rat hippocampus at 7 and 28 days after transient middle cerebral artery occlusion (tMCAO). Moreover, MCT2 overexpression promoted recovery of cognitive function after stroke. The molecular mechanism underlying these effects may be related to an increase in adenosine monophosphate-activated protein kinase-mediated mitochondrial biogenesis induced by overexpression of MCT2. Our findings suggest that MCT2 activation ameliorates cognitive impairment after stroke.

Osteogenic effect of magnesium oxychloride cement modified with phytic acid and loaded with strontium ranelate

Tingting Ma,Yijia Guan,Jinlun Feng,Yue Yang,Junying Chen,Wenjie Guo,Jianguo Liao,Yanru Zhang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Magnesium oxychloride cement has good mechanical properties, but poor water resistance. Methods Phytic acid, which can form chelate with Mg2+, was used to modify magnesium oxychloride cement, and the effects of phytic acid on the strength, in vitro degradation and biological activity of magnesium oxychloride cement were studied. Based on the preparation of phytic acid modified magnesium oxychloride cement with good water resistance and biological activity, osteoporosis treatment strontium ranelate was loaded on phytic acidmagnesium oxychloride cement, strontium ranelate/phytic acid-magnesium oxychloride cement was prepared. Results It was found that the compressive strength of 1.25 wt% phytic acid-magnesium oxychloride cement after soaking in SBF for 28 d could reach 40.5 ± 2.0 MPa, 13.33% higher than that of the control group (when phytic acid was 0 wt%), and the mass loss rate of all ages was lower than that of the control group. The water resistance of magnesium oxychloride cement was effectively improved by phytic acid. After loading with strontium ranelate, the water resistance of 1.25 wt% phytic acid-magnesium oxychloride cement was improved. Cell experiments showed that strontium ranelate could effectively promote cell proliferation and improve the expression of osteoblastrelated proteins. When strontium ranelate/phytic acid-magnesium oxychloride cement samples were implanted subcutaneously in rats for 4 w, no obvious inflammatory response was observed, and the material was tightly bound to the surrounding tissues. When bone cement was implanted into rat femur for 4 w, the bone cement was gradually wrapped and absorbed by new bone tissue, which grew from the outside to the inside, indicating that the bone cement containing strontium ranelate/phytic acid-magnesium oxychloride cement had excellent bone-forming ability. Conclusions In conclusion, the results indicated that strontium ranelate/phytic acid-magnesium oxychloride cement composite bone cement had a potential application prospect in clinical bone repair.

Deep Learning-Enhanced Hand Grip and Release Test for Degenerative Cervical Myelopathy: Shortening Assessment Duration to 6 Seconds

Yongyu Ye,Yunbing Chang,Weihao Wu,Tianying Liao,Tao Yu,Chong Chen,Zhengran Yu,Junying Chen,Guoyan Liang 대한척추신경외과학회 2024 Neurospine Vol.21 No.1

Objective: Hand clumsiness and reduced hand dexterity can signal early signs of degenerative cervical myelopathy (DCM). While the 10-second grip and release (10-s G&R) test is a common clinical tool for evaluating hand function, a more accessible method is warranted. This study explores the use of deep learning-enhanced hand grip and release test (DL-HGRT) for predicting DCM and evaluates its capability to reduce the duration of the 10-s G&R test. Methods: The retrospective study included 508 DCM patients and 1,194 control subjects. Propensity score matching (PSM) was utilized to minimize the confounding effects related to age and sex. Videos of the 10-s G&R test were captured using a smartphone application. The 3D-MobileNetV2 was utilized for analysis, generating a series of parameters. Additionally, receiver operating characteristic curves were employed to assess the performance of the 10-s G&R test in predicting DCM and to evaluate the effectiveness of a shortened testing duration. Results: Patients with DCM exhibited impairments in most 10-s G&R test parameters. Before PSM, the number of cycles achieved the best diagnostic performance (area under the curve [AUC], 0.85; sensitivity, 80.12%; specificity, 74.29% at 20 cycles), followed by average grip time. Following PSM for age and gender, the AUC remained above 0.80. The average grip time achieved the highest AUC of 0.83 after 6 seconds, plateauing with no significant improvement in extending the duration to 10 seconds, indicating that 6 seconds is an adequate timeframe to efficiently evaluate hand motor dysfunction in DCM based on DLHGRT. Conclusion: DL-HGRT demonstrates potential as a promising supplementary tool for predicting DCM. Notably, a testing duration of 6 seconds appears to be sufficient for accurate assessment, enhancing the test more feasible and practical without compromising diagnostic performance.