bluuebunny/crossref_metadata_2025_split huggingface dataset:
Involvement of the role of Chk1 in lithium‐induced G2/M phase cell cycle arrest in hepatocellular carcinoma cells
Authors: Wang Xiao‐Ming , Li Jiao , Feng Xiao‐Cheng , Wang Qiong , Guan Dong‐Yin , Shen Zong‐Hou 
Published: February 2008

AbstractLithium, a therapeutic agent for bipolar disorder, can induce G2/M arrest in various cells, but the mechanism is unclear. In this article, we demonstrated that lithium arrested hepatocellular carcinoma cell SMMC‐7721 at G2/M checkpoint by inducing the phosphorylation of cdc2 (Tyr‐15). This effect was p53 independent and not concerned with the inhibition of glycogen synthase kinase‐3 and inositol monophosphatase, two well‐documented targets of lithium. Checkpoint kinase 1 (Chk1), a critical enzyme in DNA damage‐induced G2/M arrest, was at least partially responsible for the lithium action. The lithium‐induced phosphorylation of cdc2 and G2/M arrest was abrogated largely by SB218078, a potent Chk1 inhibitor, as well as by Chk1 siRNA or the over‐expression of kinase dead Chk1. Furthermore, lithium‐induced cdc25C phosphorylation in 7721 cells and in vitro kinase assay showed that the activity of Chk1 was enhanced after lithium treatment. Interestingly, the increase of Chk1 activity by lithium may be independent of ataxia telangiectasia mutated (ATM)/ATM and Rad3‐related (ATR) kinase. This is because no elevated phosphorylation on Chk1 (Ser‐317 and Ser‐345) was observed after lithium treatment. Moreover, caffeine, a known ATM/ATR kinase inhibitor, relieved the phosphorylation of cdc2 (Tyr‐15) by hydroxyurea, but not that by lithium. Our study's results revealed the role of Chk1 in lithium‐induced G2/M arrest. Given that Chk1 has been proposed to be a novel tumor suppressor, we suggest that the effect of lithium on Chk1 and cell cycle is useful in tumor prevention and therapy. J. Cell. Biochem. 104: 1181–1191, 2008. © 2008 Wiley‐Liss, Inc.
Dimorphic expression of uncoupling protein‐3 in golden hamster harderian gland: Effects of castration and testosterone administration
Authors: Santillo Alessandra , Monteforte Rossella , De Lange Pieter , Lanni Antonia , Farina Paola , Baccari Gabriella Chieffi 
Published: February 2008

AbstractHamster (Mesocricetus auratus) harderian gland (HG) is a dimorphic orbital gland producing a copious lipid secretion. Two cell‐types are present in hamster HG, type I in both sexes, type II only in males. In hamster HGs, we found a marked sexual dichotomy in the expression of uncoupling protein‐3 (UCP3), a mitochondrial protein carrier, that probably exports fatty acid anions and fatty acid peroxides from the mitochondrial matrix. Following castration and/or testosterone treatment: (1) UCP3 levels correlated with the type II‐cell percentage, not with testosterone levels, (2) in male HGs, UCP3 was comparable to female levels at 30 days post‐castration (when the type II‐cell percentage had fallen from 50 to 5%), although testosterone was already near zero at 15 days (when neither the type II‐cell percentage nor the UCP3 level had fallen), and testosterone‐replacement therapy prevented these changes. Testosterone‐treated females possessed type II cells and a UCP3 level about twofold higher than in control females. Males displayed more intense UCP3 immunohistochemical positivity in type I HG cells than females. Hence, testosterone may indirectly control UCP3 expression by regulating the gland's morphological and lipid dimorphism. Straight‐chain fatty acids [found in alkyl diacylglycerols (ADGs) in males] are oxidized predominantly in mitochondria, branched‐chain fatty acids (abundant in ADGs in females) predominantly in peroxisomes, so we speculate that the higher UCP3 expression in males reflects greater fatty acid flux in HG mitochondria. This is supported by our finding that in female (not male) HGs, the peroxisome‐rich fraction contained α‐methylacyl‐CoA racemase (AMACR), an enzyme important in the β‐oxidation of branched‐chain fatty acids. J. Cell. Physiol. 215: 481–487, 2008. © 2008 Wiley‐Liss, Inc.
L‐ and N‐current but not M‐current inhibition by M1 muscarinic receptors requires DAG lipase activity
Authors: Liu Liwang , Heneghan John F. , Michael Gregory J. , Stanish Lee F. , Egertová Michaela , Rittenhouse Ann R. 
Published: February 2008

AbstractStimulation of postsynaptic M1 muscarinic receptors (M1Rs) increases firing rates of both sympathetic and central neurons that underlie increases in vasomotor tone, heart rate, and cognitive memory functioning. At the cellular level, M1R stimulation modulates currents through various voltage‐gated ion channels, including KCNQ K+ channels (M‐current) and both L‐ and N‐type Ca2+ channels (L‐ and N‐current) by a pertussis toxin‐insensitive, slow signaling pathway. Depletion of phosphatidylinositol‐4,5‐bisphosphate (PIP2) during M1R stimulation suffices to inhibit M‐current. We found previously that following PIP2 hydrolysis by phospholipase C, activation of phospholipase A2 and liberation of a lipid metabolite, most likely arachidonic acid (AA) are necessary for L‐ and N‐current modulation. Here we examined the involvement of a third lipase, diacylglycerol lipase (DAGL), in the slow pathway. We documented the presence of DAGL in superior cervical ganglion neurons, and then tested the highly selective DAGL inhibitor, RHC‐80267, for its capacity to antagonize M1R‐mediated modulation of whole‐cell Ca2+ currents. RHC‐80267 significantly reduced L‐ and N‐current inhibition by the muscarinic agonist oxotremorine‐M (Oxo‐M) but did not affect their inhibition by exogenous AA. Moreover, voltage‐dependent inhibition of N‐current by Oxo‐M remained in the presence of RHC‐80267, indicating selective action on the slow pathway. RHC also blocked inhibition of recombinant N‐current. In contrast, RHC‐80267 had no effect on native M‐current inhibition. These data are consistent with a role for DAGL in mediating L‐ and N‐current inhibition. These results extend our previous findings that the signaling pathway mediating L‐ and N‐current inhibition diverges from the pathway initiating M‐current inhibition. J. Cell. Physiol. 216: 91–100, 2008. © 2008 Wiley‐Liss, Inc.
ERα and AP‐1 interact in vivo with a specific sequence of the F promoter of the human ERα gene in osteoblasts
Authors: Lambertini Elisabetta , Tavanti Elisa , Torreggiani Elena , Penolazzi Letizia , Gambari Roberto , Piva Roberta 
Published: February 2008

AbstractEstrogen‐responsive genes often have an estrogen response element (ERE) positioned next to activator protein‐1 (AP‐1) binding sites. Considering that the interaction between ERE and AP‐1 elements has been described for the modulation of bone‐specific genes, we investigated the 17‐β‐estradiol responsiveness and the role of these cis‐elements present in the F promoter of the human estrogen receptor alpha (ERα) gene. The F promoter, containing the sequence analyzed here, is one of the multiple promoters of the human ERα gene and is the only active promoter in bone tissue. Through electrophoretic mobility shift (EMSA), chromatin immunoprecipitation (ChIP), and re‐ChIP assays, we investigated the binding of ERα and four members of the AP‐1 family (c‐Jun, c‐fos, Fra‐2, and ATF2) to a region located approximately 800 bp upstream of the transcriptional start site of exon F of the human ERα gene in SaOS‐2 osteoblast‐like cells. Reporter gene assay experiments in combination with DNA binding assays demonstrated that F promoter activity is under the control of upstream cis‐acting elements which are recognized by specific combinations of ERα, c‐Jun, c‐fos, and ATF2 homo‐ and heterodimers. Moreover, ChIP and re‐ChIP experiments showed that these nuclear factors bind the F promoter in vivo with a simultaneous occupancy stimulated by 17‐β‐estradiol. Taken together, our findings support a model in which ERα/AP‐1 complexes modulate F promoter activity under conditions of 17‐β‐estradiol stimulation. J. Cell. Physiol. 216: 101–110, 2008. © 2008 Wiley‐Liss, Inc.
The c‐myc apoptotic response is not intrinsic to blocking terminal myeloid differentiation
Authors: D'Angelo Santo , Liebermann Dan , Hoffman Barbara 
Published: February 2008

AbstractIt has previously been shown that deregulated c‐myc blocks terminal myeloid differentiation and prematurely recruits both the Type I and II CD95/Fas apoptotic pathways, promoting an incompletely penetrant apoptotic response. In this work it is shown that deregulated expression of either mycER or mycER™ variants also blocked terminal myeloid differentiation but failed to induce the apoptotic response, demonstrating that c‐myc can block differentiation independent of the apoptotic response. The failure of the mycER™ transgene to cause the apoptotic response is associated with reduced levels of RIP1 expression, increased Mcl‐1 expression and activation of both NF‐kB and Akt. In addition, deregulating expression of RIP1 in M1mycER™ cells restored the apoptotic response. Thus altering c‐Myc or its downstream effectors can influence the balance between apoptosis and survival, and ultimately the oncogenic potential of the c‐myc oncogene. This knowledge can be exploited to manipulate the downstream effectors, such as RIP1, to promote apoptosis and drive the death of cancer cells. J. Cell. Physiol. 216: 120–127, 2008. © 2008 Wiley‐Liss, Inc.
BMP‐2 regulation of PTHrP and osteoclastogenic factors during osteoblast differentiation of C2C12 cells
Authors: Susperregui Antonio R.G. , Viñals Francesc , Ho Patricia W.M. , Gillespie Matthew T. , Martin T. John , Ventura Francesc 
Published: February 2008

AbstractBone morphogenetic protein‐2 (BMP‐2) is strongly involved in the induction of osteoblast differentiation from mesenchymal cell precursors, as well as in enhancing bone matrix production by osteoblastic cells. Likewise, the osteoporotic phenotype of PTHrP deficient mice makes clear the importance of this paracrine regulator in bone physiology. Here, we report that BMP‐2 rapidly down‐regulated PTHrP gene expression through a transcriptional mechanism in pluripotent mesenchymal C2C12 cells, whereas BMP‐2 increased expression of PTHrP receptor. PTHrP did not significantly alter the BMP‐dependent Smad transcriptional pathway. Similarly, PTHrP did not significantly modify the BMP‐regulated expression of RANKL or OPG, cytokines involved in osteoclastogenesis. More importantly, addition of PTHrP, through the PKA signaling pathway, partially prevented the BMP‐dependent induction of some osteogenic markers such as Runx2 and Osterix in C2C12 cells. Our data suggest that BMP‐2 down‐regulation of PTHrP could facilitate terminal differentiation of osteoblasts. J. Cell. Physiol. 216: 144–152, 2008. © 2008 Wiley‐Liss, Inc.
Transcriptional profiling defines the roles of ERK and p38 kinases in epidermal keratinocytes
Authors: Gazel Alix , Nijhawan Rajiv I. , Walsh Rebecca , Blumenberg Miroslav 
Published: February 2008

AbstractEpidermal keratinocytes respond to extracellular influences by activating cytoplasmic signal transduction pathways that change gene expression. Using pathway‐specific transcriptional profiling, we identified the genes regulated by two such pathways, p38 and ERK. These pathways are at the fulcrum of epidermal differentiation, proliferative and inflammatory skin diseases. We used SB203580 and PD98059 as specific inhibitors and Affymetrix Hu133Av2 microarrays, to identify the genes regulated after 1, 4, 24, and 48 h and compared them to genes regulated by JNK. Unexpectedly, inhibition of MAPK pathways is compensated by activation of the NFκB pathway and suppression of the DUSP enzymes. Both pathways promote epidermal differentiation; however, there is a surprising disconnect between the expression of steroid synthesis enzymes and differentiation markers. The p38 pathway induces the expression of extracellular matrix and proliferation‐associated genes, while suppressing microtubule‐associated genes. The ERK pathway induces nuclear envelope and mRNA splicing proteins, while suppressing steroid synthesis and mitochondrial energy production enzymes. Transcription factors SRY, c‐FOS, and N‐Myc are the principal targets of the p38 pathway, Elk‐1 SAP1 and HLH2 of ERK, while FREAC‐4, ARNT and USF are shared. The results suggest a list of targets potentially useful in therapeutic interventions in cutaneous diseases and wound healing. J. Cell. Physiol. 215: 292–308, 2008. © 2008 Wiley‐Liss, Inc.
Radiosynthesis of (S)‐5‐methoxymethyl‐3‐[6‐(4,4,4‐trifluorobutoxy)benzo[d]isoxazol‐3‐yl] oxazolidin‐2‐[11C]one ([11C]SL25.1188), a novel radioligand for imaging monoamine oxidase‐B with PET
Authors: Bramoullé Yann , Puech Frédéric , Saba Wadad , Valette Heric , Bottlaender Michel , George Pascal , Dollé Frédéric 
Published: February 2008

AbstractWithin a novel series of 2‐oxazolidinones developed in the past by Sanofi‐Synthélabo, SL25.1188 ((S)‐5‐methoxymethyl‐3‐[6‐(4,4,4‐trifluorobutoxy)benzo[d]isoxazol‐3‐yl]oxazolidin‐2‐one), a compound that inhibits selectively and competitively MAO‐B in human and rat brain (Ki values of 2.9 and 8.5 nM for MAO‐B, respectively, and ED50 (rat): 0.6 mg/kg p.o.), was considered an appropriate candidate for imaging this enzyme with positron emission tomography. SL25.1188 was labelled with carbon‐11 (T1/2: 20.38 min) in one chemical step using the following process: (i) reaction of [11C]phosgene with the corresponding ring‐opened precursor (1.2–2.5 mg) at 100°C for 2 min in dichloromethane (0.5 mL) followed by (ii) concentration to dryness of the reaction mixture and finally (iii) semi‐preparative HPLC purification on a Waters Symmetry® C18. A total of 300–500 MBq of [11C]SL25.1188 (>95% chemically and radiochemically pure) could be obtained within 30–32 min (Sep‐pak‐based formulation included) with specific radioactivities ranging from 50 to 70 GBq/µmol (3.5–7% decay‐corrected radiochemical yield, based on starting [11C]CH4). Copyright © 2008 John Wiley & Sons, Ltd.
Real time analysis of the RNAI–RNAII–Rop complex by surface plasmon resonance: from a decaying surface to a standard kinetic analysis
Authors: Di Primo Carmelo 
Published: February 2008

AbstractRNA loop–loop complexes are motifs that regulate biological functions in both prokaryotic and eukaryotic organisms. In E. coli, RNAI, an antisense RNA encoded by the ColE1 plasmid, regulates the plasmid replication by recognizing through loop–loop interactions RNAII, the RNA primer that binds to the plasmidic DNA to initiate the replication. Rop, a plasmid‐encoded homodimeric protein interacts with this transient RNAI–RNAII kissing complex. A surface plasmon resonance (SPR)‐based biosensor was used to investigate this protein‐nucleic acid ternary complex, at 5°C, in experimental conditions such as the protein binds either to the loop–loop complex while it dissociates or to a saturated stable RNAI–RNAII surface. The results show that RNAI hairpin dissociates from the RNAII surface 110 times slower in the presence of Rop than in its absence. Rop binds to RNAI–RNAII with an on‐rate of 3.6 × 106 M−1 s−1 and an off‐rate of 0.11 s−1, resulting in a binding equilibrium constant equal to 31 nM. A Scatchard‐plot analysis of the interaction monitored by SPR confirms a 1:1 complex of Rop and RNAI–RNAII as observed for non‐natural Rop–loop–loop complexes. Copyright © 2008 John Wiley & Sons, Ltd.
Mitochondrial displacements in response to nanomechanical forces
Authors: Silberberg Yaron R. , Pelling Andrew E. , Yakubov Gleb E. , Crum William R. , Hawkes David J. , Horton Mike A. 
Published: February 2008

AbstractMechanical stress affects and regulates many aspects of the cell, including morphology, growth, differentiation, gene expression and apoptosis. In this study we show how mechanical stress perturbs the intracellular structures of the cell and induces mechanical responses. In order to correlate mechanical perturbations to cellular responses, we used a combined fluorescence‐atomic force microscope (AFM) to produce well defined nanomechanical perturbations of 10 nN while simultaneously tracking the real‐time motion of fluorescently labelled mitochondria in live cells. The spatial displacement of the organelles in response to applied loads demonstrates the highly dynamic mechanical response of mitochondria in fibroblast cells. The average displacement of all mitochondrial structures analysed showed an increase of ∼40%, post‐perturbation (∼160 nm in comparison to basal displacements of ∼110 nm). These results show that local forces can produce organelle displacements at locations far from the initial point of contact (up to ∼40 µm). In order to examine the role of the cytoskeleton in force transmission and its effect on mitochondrial displacements, both the actin and microtubule cytoskeleton were disrupted using Cytochalasin D and Nocodazole, respectively. Our results show that there is no significant change in mitochondrial displacement following indentation after such treatments. These results demonstrate the role of the cytoskeleton in force transmission through the cell and on mitochondrial displacements. In addition, it is suggested that care must be taken when performing mechanical experiments on living cells with the AFM, as these local mechanical perturbations may have significant structural and even biochemical effects on the cell. Copyright © 2008 John Wiley & Sons, Ltd.
An integrative model of managerial perceptions of employee commitment: antecedents and influences on employee treatment
Authors: Shore Ted H. , Bommer William H. , Shore Lynn M. 
Published: February 2008

AbstractAn integrative model of antecedents and outcomes of managerial perceptions of employee organizational commitment was developed and tested with 490 employees of a publicly owned U.S. manufacturing firm. The results are consistent with predictions showing that self‐reported affective commitment and supervisor‐focused impression management predicted managerial perceptions of affective commitment, whereas age, tenure, education, training and development, and self‐focused impression management were related to managerial perceptions of continuance commitment. Furthermore, manager‐rated affective and continuance commitment were differentially related to supervisory treatment of the employee (i.e. receiving contingent rewards and non‐contingent punishment). The results of this study show how managers develop perceptions of affective and continuance commitment, and through their associated treatment of employees, has important implications for the ways managers may serve to enhance or detract from employee contributions to the organization. Copyright © 2008 John Wiley & Sons, Ltd.
Resolving the database sequence discrepancies for the Staphylococcus aureus bacteriophage ϕ 11 amidase
Authors: Donovan David M. , Foster‐Frey Juli , Garrett Wesley M. , Blomberg LeAnn 
Published: February 2008

AbstractThere are two conflicting primary nucleotide sequences of the Staphylococcus aureus bacteriophage ϕ 11 amidase gene in Genbank. Nucleotide sequence differences as well as alternative translational start site assignments result in three non‐identical protein sequence predictions for this amidase. Therefore, it is prudent to verify the correct phi11 amidase protein sequence, especially since multiple versions of the amidase gene have been subcloned, deletion analysis performed, and their experimental use described. There is also a resurgence of interest in the expression and use of bacteriophage lytic proteins as bactericidal agents and the ϕ 11 amidase has a high antimicrobial potential. The correct amidase sequence is identified through a combination of DNA sequence analysis and matrix‐assisted laser desorption/ionization‐time‐of‐flight mass spectrometry analysis of the recombinant purified phi11 amidase protein. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phenotypic and genotypic heterogeneity of Enterococcus species isolated from food in Southern Brazil
Authors: Pelicioli Riboldi Gustavo , Preusser de Mattos Eduardo , Guedes Frazzon Ana Paula , Alves d'Azevedo Pedro , Frazzon Jeverson 
Published: February 2008

AbstractEnterococcus is an important group of lactic acid bacteria (LAB), which inhabits the gastrointestinal tract of humans and animals. These microorganisms can also be found in large groups of foods where they can play a beneficial role during food maturation processes or, conversely, can be used as a food contamination indicator. These microorganisms have an additional importance in various aspects of clinical microbiology. The aim of this study was to investigate and determine the phenotypic and genetic diversity in 55 enterococci isolated from different food sources. Phenotypic characteristics based upon substrate hydrolysis differences were used to identify different Enterococcus species. Analysis of the resultant data divided these species into eight Enterococcus phenotype groups. E. faecalis was the food isolate species with the greatest phenotypic variability. Fifty‐five previously isolated Enterococcus strains were re‐confirmed as belonging to this genus by PCR techniques. Randomly amplified polymorphic DNA (RAPD‐PCR) was used to study the genetic variability using M13 primers and the resultant DNA fragments produced a database of different fingerprints. After statistical analyses of the RAPD‐PCR profiles, 42 patterns were obtained and 6 different Enterococcus RAPD clusters (ERC) were identified. Genetic diversity was highest in ERC I, which grouped together approximately 40% of the E. faecium and E. faecalis isolates obtained from dairy products. Samples isolated from meat and vegetables offered the greatest genotype variability. Results of the present study suggest the presence of both phenotypic and genotypic variability within enterococci strains isolated from diverse sources of food common to Southern Brazil. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of the E. coli glucose permease fused to the maltose‐binding protein
Authors: Aboulwafa Mohammad , Saier Milton H. 
Published: February 2008

AbstractThe ptsG gene that encodes the major glucose transporter of Escherichia coli, IIGlc, was inserted into a pMALE‐ampr expression vector down‐stream of the malE gene which encodes the E. coli maltose‐binding protein (MBP). IIGlc‐MBP in the 2 h high speed supernatant of cell lysates eluted from a gel filtration column showing two activity peaks. The glucose‐6‐phosphate‐dependent transphosphorylation (TP) activity of the membrane bound oligomeric peak 1 showed substrate inhibition while that of the soluble monomeric peak 2 did not. Purification of peak 2 yielded activity with weak substrate inhibition, and further gel filtration analyses showed that upon purification, some of the monomeric IIGlc‐MBP associated to higher molecular size forms. Assays of the phosphoenolpyruvate‐dependent and transphosphorylation reactions showed that the specific activity of the purified enzyme from peak 1 was approximately double that from peak 2. The results show that the monomeric IIGlc‐MBP exhibits no substrate inhibition although the oligomeric form does. Purification promotes subunit association, an increase in catalytic activity, and restoration of substrate inhibition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)