bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Efficient N‐Arylation of Heterocycles with Aryl‐, Heteroaryl‐, and Vinylboronic Acids Catalyzed by Copper Fluorapatite
Authors: Kantam Mannepalli Lakshmi , Venkanna Gopaladasu Tirupati , Kumar Kota Balaji Shiva , Subrahmanyam Vura Bala 
Published: May 2010

AbstractN‐Arylation of N‐containing heterocycles, such as pyrazoles, imidazoles, and benzimidazoles with aryl‐, heteroaryl‐, and vinylboronic acids was efficiently carried out by copper fluorapatite (CuFAP) catalyst in MeOH at room temperature under base‐free conditions. The N‐arylated heterocycles were isolated in good‐to‐excellent yields.
Study of Lysozyme Glycation Reaction by Mass Spectrometry and NMR Spectroscopy
Authors: Maekawa Yukiko , Sugiura Makiko , Takeuchi Atsuko , Tomoo Koji , Ishida Toshimasa , Kamigauchi Miyoko 
Published: May 2010

AbstractThe Advanced Glycation End Products (AGEs) are the causative substances of lifestyle‐habit illness. To elucidate the glycation mechanism of the protein, the reaction of lysozyme with D‐glucose was analyzed by the fluorescence, TOF‐MS, and 13C‐NMR spectroscopy under the physiological condition. The fluorescence intensity of lysozyme in the glycation solution increased proportionally with a reaction time of ten weeks. The MALDI‐TOF‐MS spectra of the reaction solution after two weeks showed a peak at m/z 15066, which indicated the presence of a larger molecule than the native lysozyme (m/z 14331), and new peaks at m/z 30105 (dimer) and 45000 (trimer) were also observed. The spectral analysis supported the assumption of a continuous glycation reaction of D‐glucose with lysozyme and a 30% transformation of lysozyme to the dimeric form during ten weeks. The 13C‐NMR spectra of lysozyme showed six [13C]‐labeled signals by the glycation reaction with [13C]‐glucose after two weeks of reaction. The combined analysis of TOF‐MS and 13C‐NMR spectra uncovered that first products of the glycation reaction of lysozyme with D‐glucose can be observed already three hours after starting the reaction and that nine D‐glucose units are attached during ten weeks at 37°.
Tri‐ and Tetrasubstituted N‐Phthalimidoaziridines in 1,3‐Dipolar Cycloaddition Reactions
Authors: Ushkov Alexander V. , Kuznetsov Mikhail A. , Linden Anthony , Heimgartner Heinz 
Published: May 2010

AbstractThe thermal reactions of the 2,2,3‐trisubstituted N‐phthalimidoaziridine 1a with dimethyl acetylenedicarboxylate (DMAD), thioketones 4a–4d, and dimethyl azodicarboxylate (5) proceed even at room temperature leading to the five‐membered cycloadducts 2a, 6–8, and 12, respectively, with retention of the spatial arrangement of the aziridine substituents, in contrast to the expectation based on the conservation of orbital symmetry in concerted reactions. The analogous reactions of the tetrasubstituted phthalimidoaziridine 1b with thioketones at 40° lead to the 1,3‐thiazolidine derivatives 10 and 11 as mixtures of diastereoisomers. These unexpected results may be explained by either the isomerization of the intermediate azomethine ylides or a non‐concerted stepwise cycloaddition reaction of these ylides with the dipolarophiles. The structures of some adducts have been determined by X‐ray crystallography.
Insulin-like growth factor 2 (IGF-2) potentiates BMP-9-induced osteogenic differentiation and bone formation
Authors: Chen Liang , Jiang Wei , Huang Jiayi , He Bai-Cheng , Zuo Guo-Wei , Zhang Wenli , Luo Qing , Shi Qiong , Zhang Bing-Qiang , Wagner Eric R , Luo Jinyong , Tang Min , Wietholt Christian , Luo Xiaoji , Bi Yang , Su Yuxi , Liu Bo , Kim Stephanie H , He Connie J , Hu Yawen , Shen Jikun , Rastegar Farbod , Huang Enyi , Gao Yanhong , Gao Jian-Li , Zhou Jian-Zhong , Reid Russell R , Luu Hue H , Haydon Rex C , He Tong-Chuan , Deng Zhong-Liang 
Published: May 2010

Abstract
Efficient osteogenic differentiation and bone formation from mesenchymal stem cells (MSCs) should have clinical applications in treating nonunion fracture healing. MSCs are adherent bone marrow stromal cells that can self-renew and differentiate into osteogenic, chondrogenic, adipogenic, and myogenic lineages. We have identified bone morphogenetic protein 9 (BMP-9) as one of the most osteogenic BMPs. Here we investigate the effect of insulin-like growth factor 2 (IGF-2) on BMP-9-induced bone formation. We have found that endogenous IGF-2 expression is low in MSCs. Expression of IGF-2 can potentiate BMP-9-induced early osteogenic marker alkaline phosphatase (ALP) activity and the expression of later markers. IGF-2 has been shown to augment BMP-9-induced ectopic bone formation in the stem cell implantation assay. In perinatal limb explant culture assay, IGF-2 enhances BMP-9-induced endochondral ossification, whereas IGF-2 itself can promote the expansion of the hypertropic chondrocyte zone of the cultured limb explants. Expression of the IGF antagonists IGFBP3 and IGFBP4 leads to inhibition of the IGF-2 effect on BMP-9-induced ALP activity and matrix mineralization. Mechanistically, IGF-2 is further shown to enhance the BMP-9-induced BMPR-Smad reporter activity and Smad1/5/8 nuclear translocation. PI3-kinase (PI3K) inhibitor LY294002 abolishes the IGF-2 potentiation effect on BMP-9-mediated osteogenic signaling and can directly inhibit BMP-9 activity. These results demonstrate that BMP-9 crosstalks with IGF-2 through PI3K/AKT signaling pathway during osteogenic differentiation of MSCs. Taken together, our findings suggest that a combination of BMP-9 and IGF-2 may be explored as an effective bone-regeneration agent to treat large segmental bony defects, nonunion fracture, and/or osteoporotic fracture. © 2010 American Society for Bone and Mineral Research.
Dietary-induced serum phenolic acids promote bone growth via p38 MAPK/β-catenin canonical Wnt signaling
Authors: Chen Jin-Ran , Lazarenko Oxana P , Wu Xianli , Kang Jie , Blackburn Michael L , Shankar Kartik , Badger Thomas M , Ronis Martin JJ 
Published: May 2010

Abstract
Diet and nutritional status are critical factors that influences bone development. In this report we demonstrate that a mixture of phenolic acids found in the serum of young rats fed blueberries (BB) significantly stimulated osteoblast differentiation, resulting in significantly increased bone mass. Greater bone formation in BB diet–fed animals was associated with increases in osteoblast progenitors and osteoblast differentiation and reduced osteoclastogenesis. Blockade of p38 phosphorylation eliminated effects of BB on activation of Wnt signaling in preosteoblasts. Knocking down β-catenin expression also blocked the ability of serum from BB diet–fed rats to stimulate osteoblast differentiation in vitro. Based on our in vivo and in vitro data, we propose that the underlying mechanisms of these powerful bone-promoting effects occur through β-catenin activation and the nuclear accumulation and transactivation of TCF/LEF gene transcription in bone and in osteoblasts. These results indicate stimulation of molecular events leading to osteoblast differentiation triggered by P38 MAP kinase (MAPK)/β-catenin canonical Wnt signaling results in significant increases in bone growth in young rats consuming BB-supplemented diets. Liquid chromatography/mass spectrometry (LC/MS) characterization of the serum after BB feeding revealed a mixture of simple phenolic acids that may provide a basis for developing a new treatment to increase peak bone mass and delay degenerative bone disorders such as osteoporosis. © 2010 American Society for Bone and Mineral Research.
Melatonin protects against taurolithocholic‐induced oxidative stress in rat liver
Authors: Fuentes‐Broto Lorena , Miana‐Mena Francisco J. , Piedrafita Eduardo , Berzosa César , Martínez‐Ballarín Enrique , García‐Gil Francisco A. , Reiter Russel J. , García Joaquín J. 
Published: May 2010

AbstractCholestasis, encountered in a variety of clinical disorders, is characterized by intracellular accumulation of toxic bile acids in the liver. Furthermore, oxidative stress plays an important role in the pathogenesis of bile acids. Taurolithocholic acid (TLC) was revealed in previous studies as the most pro‐oxidative bile acid. Melatonin, a well‐known antioxidant, is a safe and widely used therapeutic agent. Herein, we investigated the hepatoprotective role of melatonin on lipid and protein oxidation induced by TLC alone and in combination with FeCl3 and ascorbic acid in rat liver homogenates and hepatic membranes. The lipid peroxidation products, malondialdehyde and 4‐hydroxyalkenals (MDA + 4‐HDA), and carbonyl levels were quantified as indices of oxidative damage to hepatic lipids and proteins, respectively. In the current study, the rise in MDA + 4‐HDA levels induced by TLC was inhibited by melatonin in a concentration‐dependent manner in both liver homogenates and in hepatic membranes. Melatonin also had protective effects against structural damage to proteins induced by TLC in membranes. These results suggest that the indoleamine melatonin may potentially act as a protective agent in the therapy of those diseases that involve bile acid toxicity. J. Cell. Biochem. 110: 1219–1225, 2010. Published 2010 Wiley‐Liss, Inc.
The transcriptional programme of contact‐inhibition
Authors: Küppers Monika , Ittrich Carina , Faust Dagmar , Dietrich Cornelia 
Published: May 2010

AbstractProliferation of non‐transformed cells is regulated by cell–cell contacts, which are referred to as contact‐inhibition. Vice versa, transformed cells are characterised by a loss of contact‐inhibition. Despite its generally accepted importance for cell‐cycle control, little is known about the intracellular signalling pathways involved in contact‐inhibition. Unravelling the molecular mechanisms of contact‐inhibition and its loss during tumourigenesis will be an important step towards the identification of novel target genes in tumour diagnosis and treatment. To better understand the underlying molecular mechanisms we identified the transcriptional programme of contact‐inhibition in NIH3T3 fibroblast using high‐density microarrays. Setting the cut off: ≥1.5‐fold, P ≤ 0.05, 853 genes and 73 cDNA sequences were differentially expressed in confluent compared to exponentially growing cultures. Importing these data into GenMAPP software revealed a comprehensive list of cell‐cycle regulatory genes mediating G0/G1 arrest, which was confirmed by RT‐PCR and Western blot. In a narrow analysis (cut off: ≥2‐fold, P ≤ 0.002), we found 110 transcripts to be differentially expressed representing 107 genes and 3 cDNA sequences involved, for example, in proliferation, signal transduction, transcriptional regulation, cell adhesion and communication. Interestingly, the majority of genes was upregulated indicating that contact‐inhibition is not a passive state, but actively induced. Furthermore, we confirmed differential expression of eight genes by semi‐quantitative RT‐PCR and identified the potential tumour suppressor transforming growth factor‐β (TGF‐β)‐1‐induced clone 22 (TSC‐22; tgfb1i4) as a novel protein to be induced in contact‐inhibited cells. J. Cell. Biochem. 110: 1234–1243, 2010. Published 2010 Wiley‐Liss, Inc.
p120‐catenin is a binding partner and substrate for Group B Pak kinases
Authors: Wong Lisa Epstein , Reynolds Albert B. , Dissanayaka Nadishani T. , Minden Audrey 
Published: May 2010

AbstractPak5 is a member of the Group B p21‐activated kinases, which are effectors of the Rho family GTPases Cdc42 and Rac. Pak5 has been shown to promote cytoskeletal reorganization, inducing filopodia formation and neurite outgrowth in neuroblastoma cells. In this study, we used affinity chromatography followed by SDS–PAGE and mass spectrometry to identify potential downstream effectors of Pak5. Using this approach, we isolated p120‐catenin (p120), a known regulator of cytoskeletal reorganization and Rho GTPases. Using co‐immunoprecipitation assays we found that p120 preferentially interacts with Pak5 among the Group B Paks. Results from immunofluorescence studies revealed that Pak5 and p120 co‐localize in cells. Both Pak5 and constitutively active Pak4, the founding member of the Group B Paks, directly phosphorylate p120 in vitro. The phosphorylation was shown by Western blot and immunofluorescence to take place specifically on serine 288. This study is the first report of an upstream serine/threonine kinase that phosphorylates p120. J. Cell. Biochem. 110: 1244–1254, 2010. Published 2010 Wiley‐Liss, Inc.
Beclin 1 self‐association is independent of autophagy induction by amino acid deprivation and rapamycin treatment
Authors: Adi‐Harel Shelly , Erlich Shlomit , Schmukler Eran , Cohen‐Kedar Sarit , Segev Oshik , Mizrachy Liat , Hirsch Joel A. , Pinkas‐Kramarski Ronit 
Published: May 2010

AbstractAutophagy, a process of self‐digestion of cellular constituents, regulates the balance between protein synthesis and protein degradation. Beclin 1 represents an important component of the autophagic machinery. It interacts with proteins that positively regulate autophagy, such as Vps34, UVRAG, and Ambra1, as well as with anti‐apoptotic proteins such as Bcl‐2 via its BH3‐like domain to negatively regulate autophagy. Thus, Beclin 1 interactions with several proteins may regulate autophagy. To identify novel Beclin 1 interacting proteins, we utilized a GST‐Beclin 1 fusion protein. Using mass spectroscopic analysis, we identified Beclin 1 as a protein that interacts with GST‐Beclin 1. Further examination by cross linking and co‐immunoprecipitation experiments confirmed that Beclin 1 self‐interacts and that the coiled coil and the N‐terminal region of Beclin 1 contribute to its oligomerization. Importantly, overexpression of vps34, UVRAG, or Bcl‐xL, had no effect on Beclin 1 self‐interaction. Moreover, this self‐interaction was independent of autophagy induction by amino acid deprivation or rapamycin treatment. These results suggest that full‐length Beclin 1 is a stable oligomer under various conditions. Such an oligomer may provide a platform for further protein–protein interactions. J. Cell. Biochem. 110: 1262–1271, 2010. Published 2010 Wiley‐Liss, Inc.
Induction of nucleolin translocation by acharan sulfate in A549 human lung adenocarcinoma
Authors: Joo Eun Ji , Yang Hui , Park Youmie , Park Nam Young , Toida Toshihiko , Linhardt Robert J. , Kim Yeong Shik 
Published: May 2010

AbstractAcharan sulfate (AS), isolated from the giant African snail Achatina fulica, is a novel glycosaminoglycan, consisting primarily of the repeating disaccharide structure α‐D‐N‐acetylglucosaminyl (1 → 4) 2‐sulfoiduronic acid. AS shows anti‐tumor activity in vitro and in vivo. Despite this activity, AS is only weakly cytotoxic towards cancer cells. We examine the interactions between AS and cell‐surface proteins in an effort to explain this anti‐tumor activity. Using flow cytometry and affinity column chromatography, we confirm that AS has strong affinity to specific cell‐surface proteins including nucleolin (NL) in A549 human lung adenocarcinomas. Surprisingly, we found the translocation of NL from nucleus to cytoplasm under the stimulation of AS (100 µg/ml) in vitro. Also, as NL exits the nucleus, the levels of growth factors such as bFGF and signaling cascade proteins, such as p38, p53, and pERK, are altered. These results suggest that the communication between AS and NL plays a critical role on signal transduction in tumor inhibition. J. Cell. Biochem. 110: 1272–1278, 2010. Published 2010 Wiley‐Liss, Inc.
Protection against cellular stress by 25‐hydroxyvitamin D3 in breast epithelial cells
Authors: Peng Xinjian , Vaishnav Avani , Murillo Genoveva , Alimirah Fatouma , Torres Karen E.O. , Mehta Rajendra G. 
Published: May 2010

Abstract25‐Hydroxyvitamin D3 (25(OH)D3) is a prohormone and a major vitamin D metabolite. The discovery of (25(OH)D3) 1α‐hydroxylase in many vitamin D target organs has yielded an increased interest in defining the role(s) of 25(OH)D3 in these tissues. The etiology of cancer appears to be complex and multi‐factorial. Cellular stress (e.g., DNA damage, hypoxia, oncogene activation) has been identified as one of the key factors responsible for initiating the carcinogenesis process. In this study, we investigated whether 25(OH)D3 protects breast epithelial cells from cellular stress using an established breast epithelial cell line MCF12F. To better elucidate the role of 25(OH)D3 in the stress response, we used multiple in vitro stress models including serum starvation, hypoxia, oxidative stress, and apoptosis induction. Under all these stress conditions, 25(OH)D3 (250 nmol/L) treatment significantly protected cells against cell death. Low‐serum stress induced p53 expression accompanied with downregulation of PCNA, the presence of 25(OH)D3 consistently inhibited the alteration of p53 and PCNA, suggesting that these molecules were involved in the stress process and may be potential target genes of 25(OH)D3. miRNA microarray analysis demonstrated that stress induced by serum starvation caused significant alteration in the expression of multiple miRNAs including miR182, but the presence of 25(OH)D3 effectively reversed this alteration. These data suggest that there is a significant protective role for 25(OH)D3 against cellular stress in the breast epithelial cells and these effects may be mediated by altered miRNA expression. J. Cell. Biochem. 110: 1324–1333, 2010. © 2010 Wiley‐Liss, Inc.
Counting the cyclocized polyphenacenes
Authors: Qian Jianguo , Zhang Fuji 
Published: May 2010

AbstractIn general the cyclocized polyphenacenes have a geometric nonplanar structure. This article gives an explicit expression of the counting formula for the two types of cyclocized polyphenacenes, viz., the belt‐type and Möbius type, respectively. The result implies that almost all the belt‐type cyclocized polyphenacenes, roughly speaking, are chiral if they are sufficiently large. The numerical results for these two types with the number of phenyl rings from 3 up to 18 are listed, as an example. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010
An optimum strategy for solution chemistry using semiempirical molecular orbital method. II. Primary importance of reproducing electrostatic interaction in the QM/MM framework
Authors: Koyano Yoshiyuki , Takenaka Norio , Nakagawa Yukinori , Nagaoka Masataka 
Published: May 2010

AbstractFor the purpose of executing direct dynamic and statistical calculation of chemical reactions in solution, we proposed an optimum strategy using semiempirical molecular orbital (MO) method with neglect of diatomic differential overlap (NDDO) approximation with specific solution reaction parameters (SSRPs), that is, the NDDO‐SSRP method. It has been further extended to develop the NDDO‐MAIS‐SSRP method, which is the NDDO‐SSRP method reinforced with the method adopted for intermolecular studies (MAIS), to correct the description of the intermolecular core–core repulsion interaction energy. In this strategy, the empirical parameters of the semiempirical MO method are optimized individually for a target chemically reacting molecular system by reference to the ab initio MO calculation data for a lot of instantaneous geometries on the potential energy surface near the reaction path. For demonstration, the NDDO‐MAIS‐SSRP method was applied, within the QM/MM framework, to a molecular cluster, that is, a couple of a QM solute NH3H2O molecule pair and a MM solvent H2O molecule. The NDDO‐MAIS‐SSRP method can reproduce the electrostatic energy in the region R > 4.0 Å, though the electrostatic energy shows large difference with those of MP2 level calculations in the region R < 4.0 Å in some cases. Both the NDDO‐SSRP and the NDDO‐MAIS‐SSRP methods could promise in the dynamical application to chemical reaction in solution (Takenaka et al., Chem Phys Lett 2010, 485, 119; Koyano et al., Bull Chem Soc Jpn, in press). © 2010 Wiley Periodicals, Inc. J Comput Chem 2010
The role of water in the proton transfer reaction mechanism in tryptophan
Authors: Vöhringer‐Martinez Esteban , Toro‐Labbé Alejandro 
Published: May 2010

AbstractThe role of water in the proton transfer mechanism between the carboxylic and the amino group in tryptophan was studied through the direct, intramolecular reaction in presence of a continuum and the single water molecule mediated, intermolecular reaction in vacuum and in presence of a continuum. The introduction of the continuum reduced the activation barriers for the proton transfer from the neutral form and stabilized the zwitterion in both cases. The reaction force and the reaction electronic flux along the intrinsic reaction coordinate allowed in combination with a Natural Bond Order Analysis a more detailed description of the influence of water on the reaction mechanism. Represented as a continuum model, water reduced the energy required for bond reorganization and did not alter the first part of the intermolecular reaction, characterized through the approximation of the water molecule to the functional groups of the amino acid and a polarization of the system. The absence of a water molecule in the intramolecular proton transfer with continuum changed the reaction coordinate to a reduction of the angle between the functional groups of the amino acid leaving the energy required for bond formation unaffected. Thus, the smaller activation barrier obtained in the direct intramolecular proton transfer with continuum model in comparison to the water mediated reaction, originates from the energetically more favorable angle reduction in comparison the approximation of a water molecule. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010
Electronic structures and nonlinear optical properties of highly deformed halofullerenes C3v C60F18 and D3d C60Cl30
Authors: Tang Shu‐Wei , Feng Jing‐Dong , Qiu Yong‐Qing , Sun Hao , Wang Feng‐Di , Chang Ying‐Fei , Wang Rong‐Shun 
Published: May 2010

AbstractElectronic structures and nonlinear optical properties of two highly deformed halofullerenes C3v C60F18 and D3d C60Cl30 have been systematically studied by means of density functional theory. The large energy gaps (3.62 and 2.61 eV) between the highest occupied and lowest unoccupied molecular orbitals (HOMOs and LUMOs) and the strong aromatic character (with nucleus‐independent chemical shifts varying from −15.08 to −23.71 ppm) of C60F18 and C60Cl30 indicate their high stabilities. Further investigations of electronic property show that C60F18 and C60Cl30 could be excellent electron acceptors for potential photonic/photovoltaic applications in consequence of their large vertical electron affinities. The density of states and frontier molecular orbitals are also calculated, which present that HOMOs and LUMOs are mainly distributed in the tortoise shell subunit of C60F18 and the aromatic [18] trannulene ring of C60Cl30, and the influence from halogen atoms is secondary. In addition, the static linear polarizability $ \left\langle \alpha \right\rangle $ and second‐order hyperpolarizability $ \left\langle \gamma \right\rangle $ of C60F18 and C60Cl30 are calculated using finite‐field approach. The values of $ \left\langle \alpha \right\rangle $ and $ \left\langle \gamma \right\rangle $ for C60F18 and C60Cl30 molecules are significantly larger than those of C60 because of their lower symmetric structures and high delocalization of π electrons. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010