bluuebunny/crossref_metadata_2025 huggingface dataset:
Light deprivation improves melatonin related suppression of hippocampal plasticity
Authors: Talaei Sayyed Alireza , Sheibani Vahid , Salami Mahmoud
Published: May 2009

In early postnatal life, sensory inputs deeply influence development as well as function of the brain. Plasticity of synaptic transmission including its experimentally induced form, long‐term potentiation (LTP), is affected by sensory deprivation in neocortex. This study is devoted to assess if dark rearing and a dark phase synthesized hormone melatonin influence LTP in the hippocampus, an area of brain involved in learning and memory. In vivo experiments were carried out on two groups of 45‐days‐old male Wistar rats kept in standard 12‐h light/dark condition [light reared (LR) tested during the light phase] or in complete darkness [dark reared (DR)] since birth to testing. Each group, in turn, was divided to two, vehicle‐ and melatonin‐treated, groups. Stimulating the Schaffer collaterals of CA3 area of hippocampus extracellular postsynaptic potentials (EPSPs) were recorded in the CA1 area. Having the stable baseline responses to the test pulses, the hippocampus was perfused by either vehicle or 2 μg melatonin and EPSPs were recorded for 30 min. Then, for induction of LTP, the tetanus was applied to the Schaffer collaterals and the field potentials were pooled for 120‐min post‐tetanus. The light deprivation resulted in a significant augmentation in the amplitude of baseline responses. Also, we observed a melatonin‐induced increase in amplitude of the baseline recordings in either LR or DR animals. Tetanic stimulation elicited LTP of EPSPs in both LR and DR groups, robustly in the former where it lasted for about 90 min. Generally, melatonin inhibited the production of LTP in the two groups especially in the LR animals leading to a noticeable depression. We concluded that higher level of neuronal activity in the DR rats gives rise to a lower level of LTP. Weaker effect of melatonin on blocking the potentiation of post‐tetanus EPSPs in the DR rats may be the result of a desensitization of melatonin receptors due to chronically increased levels of this hormone in the visually deprived rats. © 2009 Wiley‐Liss, Inc.
Secocycloartane Triterpenoidal Saponins from the Leaves of Astragalus membranaceusBunge
Authors: Kuang Haixue , Okada Yoshihito , Yang Bingyou , Tian Zhenkun , Okuyama Tohru
Published: May 2009

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Two new 9,10‐secocycloartane triterpenoidal saponins, named huangqiyenins E (1) and F (2) were isolated from the leaves of Astragalus membranaceus Bunge. Enzymatic hydrolysis of 1 and 2 afforded the aglycones huangqiyegenins III (3) and IV (4), resp. Further alkaline hydrolysis of 3 provided trideacetylhuangqiyegenin III (5). Their structures were established by detailed spectroscopic analysis as (3S,5R,6S,10R,12β,16β,24E)‐26‐(β‐D‐glucopyranosyloxy)‐10,16‐dihydroxy‐4,4,14‐trimethyl‐9,19‐cyclo‐9,10‐secocholesta‐9(11),24‐diene‐3,6,12‐triyl triacetate (1), (3S,5R,6S,10R, 16β,24E)‐26‐(β‐D‐glucopyranosyloxy)‐10,16‐dihydroxy‐4,4,14‐trimethyl‐9,19‐cyclo‐9,10‐secocholesta‐9(11), 24‐diene‐3,6‐diyl diacetate (2), (3S,5R,6S,10R,12β,16β,24E)‐10,16,26‐trihydroxy‐4,4,14‐trimethyl‐9,19‐cyclo‐9,10‐secocholesta‐9(11),24‐diene‐3,6,12‐triyl triacetate (3), (3S,5R,6S,10R,16β,24E)‐10,16,26‐trihydroxy‐4,4,14‐trimethyl‐9,19‐cyclo‐9,10‐secocholesta‐9(11),24‐diene‐3,6‐diyl diacetate (4), and (3S,5R, 6S,10R,12β,16β,24E)‐4,4,14‐trimethyl‐9,19‐cyclo‐9,10‐secocholesta‐9(11),24‐diene‐3,6,10,12,16,26‐hexol (5), resp.
Synthesis of Substituted 1,8‐Naphthyridine‐3‐carboxylates from Baylis–Hillman Adducts of Substituted 2‐Chloronicotinaldehydes
Authors: Narender Puli , Ravinder Mettu , Sadhu Partha Sarathi , China Raju Bhimapaka , Ramesh Chilukuri , Jayathirtha Rao Vaidya
Published: May 2009

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A series of substituted 1,8‐naphthyridine‐3‐carboxylates were synthesized for the first time from the Baylis–Hillman adducts obtained from 2‐chloronicotinaldehyde derivatives. Three methods were adopted to synthesize 1,8‐naphthyridine‐3‐carboxylates, of which the azide‐reduction route (Scheme 5) gave the best yields compared to the other attempted methods (Schemes 2 and 3).
Stereoselective Routes for the Total Synthesis of (+)‐Cryptocarya Diacetate
Authors: Sabitha Gowravaram , Reddy Nandyala M. , Prasad Muddala N. , Yadav Jhillu S.
Published: May 2009

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A stereoselective total synthesis of (+)‐cryptocarya diacetate (1) was achieved by two different routes (Schemes 2 and 3). The sequences involve LiAlH4/LiI reduction, ring‐closing metathesis, Prins cyclization, Wacker oxidation, and Wittig olefination reactions as key steps.
Two New Quinoline Alkaloid Mannopyranosides from Solidago canadensis
Authors: Li Ying‐Ke , Zhao Qing‐Jie , Hu Jiang , Zou Zui , He Xing‐Ying , Yuan Hong‐Bin , Shi Xue‐Yin
Published: May 2009

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Two novel quinoline alkaloid β‐D‐mannopyranosides, named dictamnine‐7‐β‐D‐mannopyranoside (1) and 8‐methoxydictamnine‐7‐β‐D‐mannopyranoside (2), were isolated from the whole plant of Solidago canadensis. Their structures were identified on the basis of a spectroscopic analysis.
Convenient Access to β‐Substituted Chiral Phenones
Authors: Cao Xiu‐Fang , Hu Ming , Li Fei , Lu Wen‐Chang , Yu Guang‐Ao , Liu Sheng‐Hua
Published: May 2009

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A highly enantioselective approach towards the synthesis of β‐substituted chiral ketones by utilizing Grignard reagents was achieved. The (R)‐ and (S)‐antipodes of the target chiral ketones 2a–2k were obtained with up to 100% ee from chiral N‐alkanoylcamphorsultams 1 (Scheme, Table 2). This simple, catalyst‐free, direct procedure for the formation of chiral ketones is a fascinating method for the practical syntheses of chiral synthons as valuable building blocks and important medicinal intermediates.
Stereoselective Synthesis of cis‐ and trans‐3,4‐Dihydro‐3,4,8‐trihydroxynaphthalen‐1(2H)‐one
Authors: Couché Emmanuel , Fkyerat Abdellatif , Tabacchi Raffaele
Published: May 2009

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A short and efficient protocol for the stereoselective synthesis of racemic trans‐ and cis‐3,4‐dihydro‐3,4,8‐trihydroxynaphthalen‐1(2H)‐one (1 and 2, resp.), is described, comprising nine and eight steps starting from commercial juglone (=5‐hydroxynaphthalene‐1,4‐dione; 12) (Scheme 4). Furthermore, an attempt to obtain 1 and 2 via phthalide annulation as the key step (Schemes 2 and 3) and a regioselective oxidation of the intermediate 1,2,3,4‐tetrahydronaphthalene‐1,2,4,5‐tetrols 27 and 28 with activated MnO2 were carried out (Scheme 4).
Nitrogen‐Rich Salts Based on the Energetic 5,5′‐(Hydrazine‐1,2‐diyl)bis[1H‐tetrazolide] Anion
Authors: Eberspächer Moritz , Klapötke Thomas M. , Miró Sabaté Carles
Published: May 2009

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The reaction of 5,5′‐(hydrazine‐1,2‐diyl)bis[1H‐tetrazole] (HBT) with N‐bases yielded a new family of energetic N‐rich salts based on the 5,5′‐(hydrazine‐1,2‐diyl)bis[1H‐tetrazol‐1‐ide] anion with ammonium (see 1), hydrazinium (see 2), guanidinium (see 3), and aminoguanidinium (see 4) cations (5,5′‐(hydrazine‐1,2‐diyl)bis[1H‐tetrazol‐1‐ide]=5,5′‐(hydrazine‐1,2‐diyl)bis[tetrazolate]). All compounds were characterized by analytical and spectroscopic methods, and the crystal structure of 1 was determined by X‐ray analysis (triclinic, P$\bar 1$). (Carboxyamino)guanidine betaine monohydrate (=2‐(aminoiminomethyl)hydrazinecarboxylic acid hydrate (1 : 1); 5) was obtained as a by‐product in the synthesis of 4 and was characterized by X‐ray analysis (monoclinic, P21/c). Differential‐scanning calorimetric (DSC) measurements were used to assess the thermal behavior of the energetic salts 1–4, and bomb calorimetry allowed us to determine the experimental constant‐volume energies of formation $\rm{(\Delta _{\rm{c}} U_{\exp} )}$. In addition, the detonation parameters (pressure and velocity) were calculated from the energies of formation (back‐calculated from $\rm{\Delta _{\rm{c}} U_{\exp} }$) with the EXPLO5 code, and their validity was checked by comparison with the results obtained from theoretical constant‐volume energies of formation $\rm{(\Delta _{\rm{c}} U_{{\rm{pred}}} )}$ obtained by means of quantum‐chemical calculation (MP2) of electronic energies and an approximation of lattice enthalpy. Lastly, the sensitivity to shock, friction, and electrostatic discharge of 1–4 was measured by submitting the compounds to standard tests, and the ICT code was used to predict the products formed upon decomposition of the salts.
Comparison of DNA Complex Formation Behaviour for Two Closely Related Lexitropsin Analogues
Authors: Parkinson John A. , Khalaf Abedawn I. , Anthony Nahoum G. , MacKay Simon P. , Suckling Colin J. , Waigh Roger D.
Published: May 2009

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Two closely related lexitropsin analogues that differ only in the form of the ‘headgroup’ functionality (CHO (for 1) vs. Ac (for 2)) have been studied in their DNA‐binding capacity for the sequence d(GCATATATGC) using 1H‐NMR spectroscopy. DNA‐Complex formation for the CHO derivative was apparent from the observation of new NMR signals on titration of DNA with ligand. Detailed investigation and assignment of the data for a ligand/DNA‐duplex ratio of 2 : 1 clearly delineated the structure as one associated with the ‘minor groove’ class of DNA complexes. The structure of the complex was determined on the basis of the acquired NMR data. Features characteristic of typical 2 : 1 minor‐groove complexes were apparent. In a similar experimental approach, the Ac analogue ligand–DNA binding response was investigated. Despite the close similarity in chemical structure to the CHO case, the Ac analogue was found to produce NMR data of a much poorer quality. This was attributed to more rapid on/off chemical exchange equilibrium between ligand and DNA. From close analysis and comparison of the NMR data for the ‘Ac’ and ‘CHO’ headgroup ligand–DNA complexes, it was possible to ascertain that the same type of complex formed in each case but with different relative binding constants. Consideration of the nature and form of these complexes has been made with reference to a previously determined structure from our laboratory for the related lexitropsin analogue thiazotropsin A.
Two New Secolignans from the Roots of Urtica fissa E. Pritz
Authors: Ji Bao‐Quan , Yan Xing‐Guo , Duan Li‐Xin , Tang Ling , Shi Li‐Ying , Wang Yong‐Qi , Feng Bao‐Min
Published: May 2009

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Two new secolignans, {(3S,4S)‐4‐[bis(4‐hydroxy‐3‐methoxyphenyl)methyl]‐2‐oxotetrahydrofuran‐3‐yl}methyl β‐D‐glucopyranoside (1) and its stereoisomer {(3S,4R)‐4‐[bis(4‐hydroxy‐3‐methoxyphenyl)methyl]‐2‐oxotetrahydrofuran‐3‐yl}methyl β‐D‐glucopyranoside (2), have been isolated from the roots of Urtica fissa E. Pritz. Their structures were determined based on spectroscopic methods (HR‐MS, 1D‐ and 2D‐NMR, HMBC, HSQC, and NOESY).
Simple and Efficient Friedel–Crafts Alkylation of 1H‐Indole with Electron‐Deficient Alkenes Promoted by Zinc Acetate
Authors: Meshram Harshadas Mitaram , Kumar Dachepally Aravind , Reddy Bandi Chennakesava
Published: May 2009

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An efficient method for the Friedel–Crafts alkylation of 1H‐indole with nitro alkenes in the presence of zinc acetate is described. The procedure is applicable to a variety of nitro alkenes and substituted indoles, and the yields are very high.
Unexpected Kinetics in the Polymerization of Ethene by Cp$\rm{ {_{2}^{{\ast}}}}$ZrCl2/MAO
Authors: di Lena Fabio , Chen Peter
Published: May 2009

A sterically hindered metallocene catalyst, Cp$\rm{ {_{2}^{{\ast}}}}$ZrCl2 activated with methylaluminoxane (MAO), is found to polymerize ethene at temperatures up to 60° with a good propagation rate constant but low number of active sites, and with negligible β‐hydride elimination or β‐hydride transfer to monomer. Moreover, transmetalation to Al is found to be effectively irreversible for alkyl groups larger than Me. With the major mechanisms for chain transfer and termination suppressed, one might expect a living polymerization. The bulk polymerization of ethene was indeed found to be quasi‐living even when performed at well above room temperature, and furthermore provided rate constants which agreed remarkably well with those from the mass‐spectrometric study.
Hydrological modelling of the Kangsabati river under changed climate scenario: case study in India
Authors: Dhar Sujana , Mazumdar Asis
Published: May 2009

India is a large developing country with nearly two‐thirds of the population depending directly on the climate‐sensitive sectors such as agriculture, fisheries and forests. A very well‐calibrated Soil and Water Assessment Tool (R2 = 0·9968, NSE = 0·91) was exercised over the Kangsabati river watershed in Bankura district of West Bengal, India, for a year including monsoon and non‐monsoon period in order to evaluate projected parameters for agricultural activities. Evapotranspiration, transmission losses, potential evapotranspiration and lateral flow to reach are evaluated from the years 2041–2050 in order to generate a picture for sustainable development of the river basin and its inhabitants. The projected climate change under various scenarios is likely to have implications on food production, water supply, biodiversity and livelihoods. India has a significant stake in scientific advancement as well as an international understanding to promote mitigation and adaptation. This requires improved scientific understanding, capacity building, networking and broad consultation processes. This paper is a commitment towards the planning, management and development of the water resources of the Kangsabati river by presenting detailed future scenarios of the Kangsabati river basin over the mentioned time period. The major findings of this paper were that of all the chosen projected parameters, transmission losses, soil water content, potential evapotranspiration, evapotranspiration and lateral flow to reach, display an increasing trend over the time period of years 2041–2050. Copyright © 2009 John Wiley & Sons, Ltd.
Immunization with a P53 synthetic long peptide vaccine induces P53‐specific immune responses in ovarian cancer patients, a phase II trial
Authors: Leffers Ninke , Lambeck Annechien J.A. , Gooden Marloes J.M. , Hoogeboom Baukje‐Nynke , Wolf Rinze , Hamming Ineke E. , Hepkema Bouke G. , Willemse Pax H.B. , Molmans Barbara H.W. , Hollema Harry , Drijfhout Jan W. , Sluiter Willem J. , Valentijn A. Rob P.M. , Fathers Loraine M. , Oostendorp Jaap , van der Zee Ate G.J. , Melief Cornelis J. , van der Burg Sjoerd H. , Daemen Toos , Nijman Hans W.
Published: May 2009

The prognosis of ovarian cancer, the primary cause of death from gynecological malignancies, has only modestly improved over the last decades. Immunotherapy is one of the new treatment modalities explored for this disease. To investigate safety, tolerability, immunogenicity and obtain an impression of clinical activity of a p53 synthetic long peptide (p53‐SLP) vaccine, twenty patients with recurrent elevation of CA‐125 were included, eighteen of whom were immunized 4 times with 10 overlapping p53‐SLP in Montanide ISA51. The first 5 patients were extensively monitored for toxicity, but showed no ≥ grade 3 toxicity, thus accrual was continued. Overall, toxicity was limited to grade 1 and 2, mostly locoregional, inflammatory reactions. IFN‐γ producing p53‐specific T‐cell responses were induced in all patients who received all 4 immunizations as measured by IFN‐γ ELISPOT. An IFN‐γ secretion assay showed that vaccine‐induced p53‐specific T‐cells were CD4+, produced both Th1 and Th2 cytokines as analyzed by cytokine bead array. Notably, Th2 cytokines dominated the p53‐specific response. P53‐specific T‐cells were present in a biopsy of the last immunization site of at least 9/17 (53%) patients, reflecting the migratory capacity of p53‐specific T‐cells. As best clinical response, stable disease evaluated by CA‐125 levels and CT‐scans, was observed in 2/20 (10%) patients, but no relationship was found with vaccine‐induced immunity. This study shows that the p53‐SLP vaccine is safe, well tolerated and induces p53‐specific T‐cell responses in ovarian cancer patients. Upcoming trials will focus on improving T helper‐1 polarization and clinical efficacy. © 2009 UICC
HOXA methylation in normal endometrium from premenopausal women is associated with the presence of ovarian cancer: A proof of principle study
Authors: Widschwendter Martin , Apostolidou Sophia , Jones Allison A. , Fourkala Evangelia O. , Arora Rupali , Pearce Celeste Leigh , Frasco Melissa A. , Ayhan Ayse , Zikan Michal , Cibula David , Iyibozkurt Cem A. , Yavuz Ekrem , Hauser‐Kronberger Cornelia , Dubeau Louis , Menon Usha , Jacobs Ian J.
Published: May 2009

DNA methylation of polycomb group target (PCGT) genes is an early step in carcinogenesis and could potentially be assayed to determine cancer risk prediction. To assess whether methylation changes in PCGT genes in normal tissue is able to predict the presence of cancer, we studied HOXA gene methylation in normal endometrium from premenopausal ovarian cancer patients and age‐matched healthy controls without ovarian cancer. DNA methylation of HOXA9 and HOXA11 genes in normal endometrium was associated with ovarian cancer in an initial test set and this was subsequently confirmed in independent validation sample sets. The overall risk of ovarian cancer was increased 12.3‐fold by high HOXA9 methylation for all stages, and 14.8‐fold for early stage ovarian cancers, independent of age, phase of the menstrual cycle and histology of the cancer. The results of this proof of principle study demonstrate the potential to detect ovarian cancer via analysis of normal endometrial cells and provide insight into the possible contribution of this novel approach in ovarian cancer risk prediction and prevention. © 2009 UICC
Hypoxia induces chemoresistance in ovarian cancer cells by activation of signal transducer and activator of transcription 3
Authors: Selvendiran Karuppaiyah , Bratasz Anna , Kuppusamy M. Lakshmi , Tazi Mia F. , Rivera Brian K. , Kuppusamy Periannan
Published: May 2009

Signal transducer and activator of transcription 3 (STAT3) is activated in a variety of human cancers, including ovarian cancer. The molecular mechanism by which the STAT3 is activated in cancer cells is poorly understood. We observed that human ovarian xenograft tumors (A2780) in mice were severely hypoxic (pO2 ∼ 2 mmHg). We further observed that hypoxic exposure significantly increased the phosphorylation of STAT3 (pSTAT3) at the Tyr705 residue in A2780 cell line. The pSTAT3 (Tyr705) level was highly dependent on cellular oxygenation levels, with a significant increase at <2% O2, and without any change in the pSTAT3 (Ser727) or total STAT3 levels. The pSTAT3 (Tyr705) elevation following hypoxic exposure could be reversed within 12 hr after returning the cells to normoxia. The increased level of pSTAT3 was partly mediated by increased levels of reactive oxygen species generation in the hypoxic cancer cells. Conventional chemotherapeutic drugs cisplatin and taxol were far less effective in eliminating the hypoxic ovarian cancer cells suggesting a role for pSTAT3 in cellular resistance to chemotherapy. Inhibition of STAT3 by AG490 followed by treatment with cisplatin or taxol resulted in a significant increase in apoptosis suggesting that hypoxia‐induced STAT3 activation is responsible for chemoresistance. The results have important clinical implications for the treatment of hypoxic ovarian tumors using STAT3‐specific inhibitors. © 2009 UICC
Tumor ZAC1 expression is associated with the response to somatostatin analog therapy in patients with acromegaly
Authors: Theodoropoulou Marily , Tichomirowa Maria A. , Sievers Caroline , Yassouridis Alexander , Arzberger Thomas , Hougrand Olivier , Deprez Manuel , Daly Adrian F. , Petrossians Patrick , Pagotto Uberto , Beckers Albert , Stalla Günter K.
Published: May 2009

Somatostatin analogs (SSA) with their potent antisecretory and antiproliferative effects are the main medical treatment option for patients with neuroendocrine tumors, such as gastroenteropancreatic and acromegaly‐associated growth hormone secreting pituitary tumors. Although a good portion of acromegalic patients gets normalized after SSA treatment, strict hormonal control is not achieved in a sizeable proportion of these patients. The reasons for this incomplete response to SSA treatment are unclear. We have found that the tumor suppressor ZAC1 (LOT1/PLAGL1) is essential for the antiproliferative effect of SSA in pituitary tumor cells. The aim of the present retrospective cohort study was to determine whether ZAC1 immunoreactivity in archival somatotrophinoma tissue derived from 45 patients with acromegaly routinely pretreated with SSA before surgery, was associated with response to SSA (normalization of GH, IGF‐I and presence of tumor shrinkage). All tumors displayed ZAC1 immunoreactivity [weak (+; n = 15), moderate (++; n = 16) and strong (+++; n = 14)]. A significant positive correlation was found between strong ZAC1 immunoreactivity and IGF‐I normalization and presence of tumor shrinkage after SSA treatment, which was not affected by age at diagnosis, gender or duration of SSA treatment. These in vivo data combined with the antiproliferative properties of ZAC1/Zac1 provide evidence of a mechanistic role for this transcription factor on SSA induced tumor shrinkage and hormone normalization. © 2009 UICC
TP53 Arg72Pro polymorphism and lung cancer risk: A meta‐analysis
Authors: Yan Lili , Zhang Deqiang , Chen Chengwen , Mao Yumin , Xie Yi , Li Yao , Huang Yan , Han Baohui
Published: May 2009

No clear consensus has been reached on the TP53 Arg72Pro polymorphism (G12139C) and lung cancer risk. Thus, a meta‐analysis was conducted to summarize the possible association. There was no statistical association between 12139C (Pro allele) and lung cancer risk in Caucasians compared with 12139G allele. However, the association was observed in all subjects (9,387 patients and 9,922 controls, p = 0.04, OR = 1.08, 95% CI 1.00–1.17), as well as in Asians (p = 0.0004, OR = 1.14, 95% CI 1.06–1.22). The association was also found in Asians under recessive genetic model (p < 0.00001, OR = 1.37, 95% CI 1.20–1.57) and homozygote comparison (CC vs. GG) (p < 0.0001, OR = 1.34, 95% CI 1.16–1.56). 12139C allele might increase the lung adenocarcinoma risk compared with 12139G allele (p = 0.01, OR = 1.11, 95% CI 1.02–1.21), and the effect was also found under recessive genetic model (p = 0.003, OR = 1.28, 95% CI 1.09–1.50) and homozygote comparison (CC vs. GG) (p = 0.007, OR = 1.28, 95% CI 1.07–1.52). There was an elevated association between the 12139C and the stage I lung cancer under dominant genetic model (p = 0.04, OR = 1.48, 95% CI 1.02–2.16), but no association was observed in other stages. No association of smoking was found between 12139C allele and lung cancer under recessive genetic model. Our result indicated that 12139C might increase the risk of lung cancer under recessive genetic model in adenocarcinoma, in Asians, and in lung cancer stage I. More studies stratified for lung cancer stage‐genotyping interaction should be performed to clarify the role of TP53 Arg72Pro polymorphism in the development of lung cancer. © 2009 UICC
Intrinsic resistance to the MEK1/2 inhibitor AZD6244 (ARRY‐142886) is associated with weak ERK1/2 signalling and/or strong PI3K signalling in colorectal cancer cell lines
Authors: Balmanno Kathryn , Chell Simon D. , Gillings Annette S. , Hayat Shaista , Cook Simon J.
Published: May 2009

Mutations in KRAS or BRAF frequently manifest in constitutive activation of the MEK1/2‐ERK1/2 signalling pathway. The MEK1/2‐selective inhibitor, AZD6244 (ARRY‐142886), blocks ERK1/2 activation and is currently undergoing clinical evaluation. Tumour cells can vary markedly in their response to MAPK or ERK kinase (MEK) inhibitors, and the presence of a BRAF mutation is thought to predict sensitivity, with the RAS mutations being associated with intrinsic resistance. We analysed cell proliferation in a panel of 19 colorectal cancer cell lines and found no simple correlation between BRAF or KRAS mutation and sensitivity to AZD6244, though cells that harbour neither mutation tended to be resistant. Cells that were sensitive arrested in G1 and/or underwent apoptosis and the presence of BRAF or KRAS mutation was not sufficient to predict either fate. Cell lines that were resistant to AZD6244 exhibited low or no ERK1/2 activation or exhibited coincident activation of ERK1/2 and protein kinase B (PKB), the latter indicative of activation of the PI3K pathway. In cell lines with coincident ERK1/2 and PKB activation, sensitivity to AZD6244 could be re‐imposed by any of the 3 distinct PI3K/mTOR inhibitors. We conclude that AZD6244 is effective in colorectal cancer cell lines with BRAF or KRAS mutations. Sensitivity to MEK1/2 inhibition correlates with a biochemical signature; those cells with high ERK1/2 activity (whether mutant for BRAF or KRAS) evolve a dependency upon that pathway and tend to be sensitive to AZD6244 but this can be offset by high PI3K‐dependent signalling. This may have implications for the use of MEK inhibitors in combination with PI3K inhibitors. © 2009 UICC
Three‐ and four‐dimensional visualization of cell migration using optical coherence tomography
Authors: Rey Sara M. , Považay Boris , Hofer Bernd , Unterhuber Angelika , Hermann Boris , Harwood Adrian , Drexler Wolfgang
Published: May 2009

Conventionally, cell chemotaxis is studied on two‐dimensional (2D) transparent surfaces, due to limitations in optical and image data‐collection techniques. However, surfaces that more closely mimic the natural environment of cells are often opaque. Optical coherence tomography (OCT) is a noninvasive label‐free imaging technique, which offers the potential to visualize moving cells on opaque surfaces and in three dimensions (3D). Here, we demonstrate that OCT is an effective means of time‐lapse videomicroscopy of Dictyostelium cells undergoing 3D (2D+time) cell migration on nitrocellulose substrates and 4D (3D+time) chemotaxis within low‐density agarose gels. The generated image sequences are compatible with current computer‐based image‐analysis software for quantification of cell motility. This demonstrates the utility of OCT for cell tracking and analysis of cell chemotaxis in complex environments. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transforming growth factor‐β3‐induced Smad signaling regulates actin reorganization during chondrogenesis of chick leg bud mesenchymal cells
Authors: Kim Dongkyun , Kim Jungsoo , Kang Shin‐Sung , Jin Eun‐Jung
Published: May 2009

Endochondral ossification is characterized by a significant interdependence between cell shape and cytoskeletal organization that accompanies the onset of chondrogenic signaling. However, the mechanisms mediating these interactions have not been well studied. Here, treatment with transforming growth factor (TGF)‐β3 at a later stage of chondrogenesis led to activation of Smad‐2 signaling and the formation of intense stress fibers, which resulted in suppressing chondrogenic differentiation of leg bud mesenchymal cells. Moreover, specific siRNA knockdown of Smad‐2 reduced TGF‐β3‐induced stress fibers via physical interactions with β‐catenin. In conclusion, our results indicate that TGF‐β3‐induced Smad signaling, in conjunction with β‐catenin, is involved in the reorganization of the actin cytoskeleton into a cortical pattern with a concomitant rounding of cells. J. Cell. Biochem. © 2009 Wiley‐Liss, Inc.

This article was published online on 28 May 2009. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 8 June 2009. J. Cell. Biochem. 107: 622–629, 2009. © 2009 Wiley‐Liss, Inc.
Identification and characterization of the mitochondrial targeting sequence and mechanism in human citrate synthase
Authors: Cheng Tsung‐Lin , Liao Ching‐Chun , Tsai Wen‐Hui , Lin Chin‐Chih , Yeh Chin‐Wei , Teng Chiao‐Fang , Chang Wen‐Tsan
Published: May 2009

Citrate synthase (CS), the first and rate‐limiting enzyme of the tricarboxylic acid (TCA) cycle, plays a decisive role in regulating energy generation of mitochondrial respiration. Most mitochondrial proteins are synthesized in the cytoplasm as preproteins with an amino (N)‐terminal mitochondrial targeting sequence (MTS) that directs mitochondria‐specific sorting of the preprotein. However, the MTS and targeting mechanism of the human CS protein are not fully characterized. The human CS gene is a single nuclear gene which transcribes into two mRNA variants, isoform a (CSa) and b (CSb), by alternative splicing of exon 2. CSa encodes 466 amino acids, including a putative N‐terminal MTS, while CSb expresses 400 residues with a shorter N terminus, lacking the MTS. Our results indicated that CSa is localized in the mitochondria and the N‐terminal 27 amino acids, including a well‐conserved RXY ↓ (S/A) motif (the RHAS sequence), can efficiently target the enhanced green fluorescent protein (EGFP) into the mitochondria. Furthermore, site‐directed mutagenesis analysis of the conserved basic amino acids and serine/threonine residues revealed that the R9 residue is essential but all serine/threonine residues are dispensable in the mitochondrial targeting function. Moreover, RNA interference (RNAi)‐mediated gene silencing of the preprotein import receptors, including TOM20, TOM22, and TOM70, showed that all three preprotein import receptors are required for transporting CSa into the mitochondria. In conclusion, we have experimentally identified the mitochondrial targeting sequence of human CSa and elucidated its targeting mechanism. These results provide an important basis for the study of mitochondrial dysfunction due to aberrant CSa trafficking. J. Cell. Biochem. 107: 1002–1015, 2009. © 2009 Wiley‐Liss, Inc.
Interferon‐γ suppresses Na+–H+exchanger in cultured human endolymphatic sac epithelial cells
Authors: Son Eun Jin , Moon In Seok , Kim Sung Huhn , Kim Su Jin , Choi Jae Young
Published: May 2009

Adequate regulation of endolymphatic pH is essential for maintaining inner ear function. The Na+–H+exchanger (NHE) is a major determinant of intracellular pH (pHi), and facilitates Na+and fluid absorption in various epithelia. We determined the functional and molecular expression of NHEs in cultured human endolymphatic sac (ES) epithelial cells and examined the effect of IFN‐γ on NHE function. Serial cultures of human ES epithelial cells were generated from tissue samples. The molecular expression of NHE1, ‐2, and ‐3 isoforms was determined by real‐time RT‐PCR. The functional activity of NHE isoforms was measured microfluorometrically using a pH‐sensitive fluorescent dye, 2′,7′‐bis(carbonylethyl)‐5(6)‐carboxyfluorescein (BCECF), and a NHE‐inhibitor, 3‐methylsulfonyl‐4‐piperidinobenzoyl guanidine methanesulfonate (HOE694). NHE1, ‐2, and ‐3 mRNAs were expressed in human ES epithelial cells. Functional activity of NHE1 and ‐2 was confirmed in the luminal membrane of ES epithelial cells by sequentially suppressing Na+‐dependent pHirecovery from intracellular acidification using different concentrations of HOE694. Treatment with IFN‐γ (50 nM for 24 h) suppressed mRNA expression of NHE1 and ‐2. IFN‐γ also suppressed functional activity of both NHE1 and ‐2 in the luminal membrane of ES epithelial cells. This study shows that NHEs are expressed in cultured human ES epithelial cells and that treatment with IFN‐γ suppresses the expression and functional activity of NHE1 and ‐2. J. Cell. Biochem. 107: 965–972, 2009. © 2009 Wiley‐Liss, Inc.
Using Gaussian model to improve biological sequence comparison
Authors: Dai Qi , Liu Xiaoqing , Li Lihua , Yao Yuhua , Han Bin , Zhu Lei
Published: May 2009

One of the major tasks in biological sequence analysis is to compare biological sequences, which could serve as evidence of structural and functional conservation, as well as of evolutionary relations among the sequences. Numerous efficient methods have been developed for sequence comparison, but challenges remain. In this article, we proposed a novel method to compare biological sequences based on Gaussian model. Instead of comparing the frequencies of k‐words in biological sequences directly, we considered the k‐word frequency distribution under Gaussian model which gives the different expression levels of k‐words. The proposed method was tested by similarity search, evaluation on functionally related genes, and phylogenetic analysis. The performance of our method was further compared with alignment‐based and alignment‐free methods. The results demonstrate that Gaussian model provides more information about k‐word frequencies and improves the efficiency of sequence comparison. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Assessment of biomolecular force fields for molecular dynamics simulations in a protein crystal
Authors: Hu Zhongqiao , Jiang Jianwen
Published: May 2009

Different biomolecular force fields (OPLS‐AA, AMBER03, and GROMOS96) in conjunction with SPC, SPC/E and TIP3P water models are assessed for molecular dynamics simulations in a tetragonal lysozyme crystal. The root mean square deviations for the Ca atoms of lysozymes are about 0.1 to 0.2 nm from OPLS‐AA and AMBER03, smaller than 0.4 nm from GROMOS96. All force fields exhibit similar pattern in B‐factors, whereas OPLS‐AA and AMBER03 accurately reproduce experimental measurements. Despite slight variations, the primary secondary structures are well conserved using different force fields. Water diffusion in the crystal is approximately ten‐fold slower than in bulk phase. The directional and average water diffusivities from OPLS‐AA and AMBER03 along with SPC/E model match fairly well with experimental data. Compared to GROMOS96, OPLS‐AA and AMBER03 predict larger hydrophilic solvent‐accessible surface area of lysozyme, more hydrogen bonds between lysozyme and water, and higher percentage of water in hydration shell. SPC, SPC/E and TIP3P water models have similar performance in most energetic and structural properties, but SPC/E outperforms in water diffusion. While all force fields overestimate the mobility and electrical conductivity of NaCl, a combination of OPLS‐AA for lysozyme and the Kirkwood‐Buff model for ions is superior to others. As attributed to the steric restraints and surface interactions, the mobility and conductivity in the crystal are reduced by one to two orders of magnitude from aqueous solution. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Computational studies on electron and proton transfer in phenol‐imidazole‐base triads
Authors: Yan Shihai , Kang Sunwoo , Hayashi Tomoyuki , Mukamel Shaul , Lee Jin Yong
Published: May 2009

The electron and proton transfer in phenol‐imidazole‐base systems (base = NH2− or OH−) were investigated by density‐functional theory calculations. In particular, the role of bridge imidazole on the electron and proton transfer was discussed in comparison with the phenol‐base systems (base = imidazole, H2O, NH3, OH−, and NH2−). In the gas phase phenol‐imidazole‐base system, the hydrogen bonding between the phenol and the imidazole is classified as short strong hydrogen bonding, whereas that between the imidazole and the base is a conventional hydrogen bonding. The n value in spn hybridization of the oxygen and carbon atoms of the phenolic CO sigma bond was found to be closely related to the CO bond length. From the potential energy surfaces without and with zero point energy correction, it can be concluded that the separated electron and proton transfer mechanism is suitable for the gas‐phase phenol‐imidazole‐base triads, in which the low‐barrier hydrogen bond is found and the delocalized phenolic proton can move freely in the single‐well potential. For the gas‐phase oxidized systems and all of the triads in water solvent, the homogeneous proton‐coupled electron transfer mechanism prevails. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
A‐type lamins and signaling: The PI 3‐kinase/Akt pathway moves forward
Authors: Marmiroli Sandra , Bertacchini Jessika , Beretti Francesca , Cenni Vittoria , Guida Marianna , De Pol Anto , Maraldi Nadir M. , Lattanzi Giovanna
Published: May 2009

Lamin A/C is a nuclear lamina constituent mutated in a number of human inherited disorders collectively referred to as laminopathies. The occurrence and significance of lamin A/C interplay with signaling molecules is an old question, suggested by pioneer studies performed in vitro. However, this relevant question has remained substantially unanswered, until data obtained in cellular and organismal models of laminopathies have indicated two main aspects of lamin A function. The first aspect is that lamins establish functional interactions with different protein platforms, the second aspect is that lamin A/C activity and altered function may elicit different effects in different cells and tissue types and even in different districts of the same tissue. Both these observations strongly suggest that signaling mechanisms targeting lamin A/C or its binding partners may regulate such a plastic behavior. A number of very recent data show involvement of kinases, as Akt and Erk, or phosphatases, as PP1 and PP2, in lamin A‐linked cellular mechanisms. Moreover, altered activation of signaling in laminopathies and rescue of the pathological phenotype in animal models by inhibitors of signaling pathways, strongly suggest that signaling effectors related to lamin A/C may be implicated in the pathogenesis of laminopathies and may represent targets of therapeutic intervention. In face of such an open perspective of basic and applied research, we review current evidence of lamin A/C interplay with signaling molecules, with particular emphasis on the lamin A‐Akt interaction and on the biological significance of their relationship. J. Cell. Physiol. 220: 553–561, 2009. © 2009 Wiley‐Liss, Inc.
MARCKS regulates lamellipodia formation induced by IGF‐I via association with PIP2 and β‐actin at membrane microdomains
Authors: Yamaguchi Hiroki , Shiraishi Mitsuya , Fukami Kiyoko , Tanabe Atsuhiro , Ikeda‐Matsuo Yuri , Naito Yasuhito , Sasaki Yasuharu
Published: May 2009

Myristoylated alanine‐rich C kinase substrate (MARCKS) is considered to participate in formation of F‐actin‐based lamellipodia, which represents the first stage of neurite formation. However, the mechanism of how MARCKS is involved in lamellipodia formation is not precisely unknown. Using SH‐SY5Y cells, we demonstrated here that MARCKS was translocated from cytosol to detergent‐resistant membrane microdomains, known as lipid rafts, within 30 min after insulin‐like growth factor‐I (IGF‐I) stimulation, which was accompanied by MARCKS dephosphorylation, β‐actin accumulation in lipid rafts, and lamellipodia formation. The protein kinase C inhibitor, Ro‐31‐8220, and Rho‐kinase inhibitors, HA1077 and Y27632, themselves decreased basal phosphorylation levels of MARCKS and coincidently elicited translocation of MARCKS to lipid rafts. On the other hand, the phosphoinositide 3‐kinase inhibitor, LY294002, abolished IGF‐I‐induced dephosphorylation, translocation of MARCKS to lipid rafts, and lamellipodia formation. Treatment of cells with neomycin, a PIP2‐masking reagent, attenuated the translocation of MARCKS to lipid rafts and the lamellipodia formation induced by IGF‐I, although dephosphorylation of MARCKS was not affected. Immunocytochemical and immunoprecipitation analysis indicated that IGF‐I stimulation induced the translocation of MARCKS to lipid rafts in the edge of lamellipodia and formation of the complex with PIP2. Moreover, we demonstrated that knockdown of endogenous MARCKS resulted in significant attenuation of IGF‐I‐induced β‐actin accumulation in the lipid rafts and lamellipodia formation. These results suggest a novel role for MARCKS in lamellipodia formation induced by IGF‐I via the translocation of MARCKS, association with PIP2, and accumulation of β‐actin in the membrane microdomains. J. Cell. Physiol. 220: 748–755, 2009. © 2009 Wiley‐Liss, Inc.
Characterization of calcium signaling pathways in human preadipocytes
Authors: Hu Rui , He Mu‐lan , Hu Hao , Yuan Bing‐Xiang , Zang Wei‐Jin , Lau Chu‐Pak , Tse Hung‐Fat , Li Gui‐Rong
Published: May 2009

Intracellular free Ca2+ (Ca) is an important regulator of many cellular activities; however, Ca2+ signaling is not well studied in human preadipocytes. The purpose of the present study was to characterize Ca2+ signal pathways using a confocal scanning technique and RT‐PCR. It was found that spontaneous Ca oscillations were observed in 12.1% preadipocytes, and number of cells with Ca2+ oscillations was increased to 47.9% by 1% fetal bovine serum. Ca oscillations were dependent on Ca2+ entry mainly via stored‐operated Ca2+ (SOC) entry. They were suppressed by the SOC entry channel blocker La3+, the phospholipase C (PLC) inhibitor U73122, the inositol trisphosphate receptor (IP3R) blocker 2‐amino‐ethoxydiphenyl borate, or the sarcoplasmic/endoplasmic reticulum Ca2+ pump (SERCA) inhibitors thapsigargin and cyclopiazonic acid, but not by ryanodine. The IP3R activator thimerosal increased Ca oscillations. In addition, the plasma membrane Ca2+ pump (PMCA) inhibitor carboxyeosin and Na+–Ca2+ exchanger (NCX) inhibitor Ni2+ both suppressed Ca2+ oscillations. RT‐PCR revealed that the mRNAs for IP3R1‐3, SERCA1,2, NCX3 and PMCA1,3,4, CaV1.2, and TRPC1,4,6, STIM1 and Orai1 (for SOC entry channels) were significant in human preadipocytes. The present study demonstrates that multiple Ca2+ signal pathways are present in human preadipocytes, and provides a basis for investigating how Ca2+ signals regulate biological and physiological activities of human preadipocytes. J. Cell. Physiol. 220: 765–770, 2009. © 2009 Wiley‐Liss, Inc.
High level of laccases production by Trametes trogii culture on olive mill wastewater‐based media, application in textile dye decolorization
Authors: Chakroun Hanen , Sayadi Sami , Mechichi Tahar , Dhouib Abdelhafidh
Published: May 2009

BACKGROUND: Laccases are receiving increasing attention as potential industrial enzymes in various applications. Therefore, it is important to find inexpensive and optimized media for large‐scale commercial production. The present work aims to valorize olive mill wastewater (OMW) by its use as base media for laccases production by Trametes trogii and use of the laccases produced for decolorizing textile dyes.

RESULTS: A high yield of 25 120 U L−1 of laccases was obtained at an OMW:water ratio of 80:20 enriched with 2 g L−1 of urea corresponding to initial biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total phenol concentrations of 18.4, 46 and 4.6 g L−1 respectively. The partially purified laccases resulted in 85% decolorization of blue tubantin GLL 300 and black tubantin VSF 600, and 45% decolorization of blue solophenyl after 6 h of incubation. Subsequent additions of the same dye dose to the reaction mixture resulted in a very significant decrease in laccases activity after the third dye addition.

CONCLUSION: The use of OMW for laccases production is a cost effective process. The laccases produced can be applied to the decolorization of textile wastewaters. Copyright © 2009 Society of Chemical Industry
Contributions of electrochemical oxidation to waste‐water treatment: fundamentals and review of applications
Authors: Anglada Ángela , Urtiaga Ane , Ortiz Inmaculada
Published: May 2009

OVERVIEW: This paper provides an overview of some fundamental aspects of electrochemical oxidation and gives updated information on the application of this technology to waste‐water treatment. In recent years, electrochemical oxidation has gained increasing interest due to its outstanding technical characteristics for eliminating a wide variety of pollutants normally present in waste‐waters such as refractory organic matter, nitrogen species and microorganisms.

IMPACT: The strict disposal limits and health quality standards set by legislation may be met by applying electrochemical oxidation. However, treatment costs have to be cut down before full‐scale application of this technology. Deployment of electrochemical oxidation in combination with other technologies and the use of renewable sources to power this process are two steps in this direction.

APPLICATIONS: Effluents from landfill and a wide diversity of industrial effluents including the agro‐industry, chemical, textile, tannery and food industry, have been effectively treated by this technology. Its high efficiency together with its disinfection capabilities makes electro‐oxidation a suitable technology for water reuse programs. Copyright © 2009 Society of Chemical Industry
Microwave photocatalysis III. Transition metal ion‐doped TiO2thin films on mercury electrodeless discharge lamps: preparation, characterization and their effect on the photocatalytic degradation of mono‐chloroacetic acid and Rhodamine B
Authors: Žabová Hana , Církva Vladimír
Published: May 2009

BACKGROUND:Mercury electrodeless discharge lamps (Hg‐EDLs) were used to generate UV radiation when exposed to a microwave field. EDLs were coated with doped TiO2in the form of thin films containing transition metal ions Mn+(M = Fe, Co, Ni, V, Cr, Mn, Zr, Ag). Photocatalytic degradation of mono‐chloroacetic acid (MCAA) to HCl, CO2, and H2O, and decomposition of Rhodamine B on the thin films were investigated in detail.

RESULTS:Polycrystalline thin doped TiO2films were prepared by dip‐coating of EDL via a sol–gel method using titaniumn‐butoxide, acetylacetone, and a transition metal acetylacetonate. The films were characterized by Raman spectroscopy, UV/Vis absorption spectroscopy, X‐ray photoelectron spectroscopy (XPS), electron microprobe analysis and by atomic force microscopy (AFM). The photocatalytic activity of doped TiO2films was monitored in the decomposition of Rhodamine B in water. Compared with the pure TiO2film, the UV/Vis spectra of V, Zr and Ag‐doped TiO2showed significant absorption in the visible region, and hence the photocatalytic degradation of MCAA had increased. The best apparent degradation rate constant (0.0125 min−1), which was higher than that on the pure TiO2film by a factor of 1.7, was obtained with the Ag(3%)/TiO2photocatalyst. The effect of doping level of vanadium acetylacetonate on the photocatalytic efficiency of the V‐doped TiO2was determined.

CONCLUSIONS:Transition metal ion‐doped TiO2thin films showed significant absorption in the visible region. The metal doped TiO2photocatalyst (with an appropriate amount of V, Zr and Ag) on the Hg‐EDLs increased the degradation efficiency of MCAA in a microwave field. Copyright © 2009 Society of Chemical Industry
Microwave‐assisted immobilization of lipase from Candida rugosa on Eupergit® supports
Authors: Bezbradica Dejan , Mijin Dušan , Mihailović Mladen , Knežević‐Jugović Zorica
Published: May 2009

BACKGROUND: Immobilization of lipase (triacylglycerol acylhydrolase EC 3.1.1.3) from Candida rugosa on Eupergit® C and Eupergit® C 250L was performed under microwave irradiation in order to reduce immobilization time. Lipase loading, hydrolytic activity, esterification activity and operational stability in organic solvent of immobilized lipase preparation were determined.

RESULTS: The microwave‐assisted procedure resulted in a 29% lower lipase loadings, compared with immobilized lipase obtained without microwaves. In hydrolytic activity assay, lipase immobilized under microwaves exhibited a 23% higher specific activity. Slight activation of lipase by microwave‐assisted immobilization was observed, since specific activity was around 5% higher than for free lipase. Lipase of highest activity was obtained after 2 min immobilization on Eupergit® C. The same preparation exhibited high esterification activity in organic medium and a half life of 212 h was determined in multiple use assay.

CONCLUSION: The application of microwave irradiation leads to reduction of immobilization time from 2 days to only 2 min. The immobilized lipase obtained has prospects for further application due to its high retained activity and stability. Copyright © 2009 Society of Chemical Industry