bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gene positional changes relative to the nuclear substructure during carbon tetrachloride‐induced hepatic fibrosis in rats
Authors: Maya‐Mendoza Apolinar , Hernández‐Muñoz Rolando , Gariglio Patricio , Aranda‐Anzaldo Armando 
Published: September 2004

AbstractIn the interphase nucleus the DNA of higher eukaryotes is organized in loops anchored to a substructure known as the nuclear matrix (NM). The topological relationship between gene sequences located in the DNA loops and the NM appears to be very important for nuclear physiology because processes such as replication, transcription, and processing of primary transcripts occur at macromolecular complexes located at discrete sites upon the NM. Mammalian hepatocytes rarely divide but preserve a proliferating capacity that is displayed in vivo after specific stimulus. We have previously shown that transient changes in the relative position of specific genes to the NM occur during the process of liver regeneration after partial ablation of the liver, but also that such changes correlate with the replicating status of the cells. Moreover, since chronic exposure to carbon tetrachloride (CCl4) leads to bouts of hepatocyte damage and regeneration, and eventually to non‐reversible liver fibrosis in the rat, we used this animal model in order to explore if genes that show differential activity in the liver change or modify their relative position to the NM during the process of liver fibrosis induction. We found that changes in the relative position of specific genes to the NM occur during the chronic administration of CCl4, but also that such changes correlate with the proliferating status of the hepatocytes that goes from quiescence to regeneration to replicative senescence along the course of CCl4‐induced liver fibrosis, indicating that specific configurations in the higher‐order DNA structure underlie the stages of progression towards liver fibrosis. © 2004 Wiley‐Liss, Inc.
Zymogen activation and characterization of a major gelatin‐cleavage activity localized to the sea urchin extraembryonic matrix
Authors: Ranganathan Lavanya , Rimsay Robert , Robinson John J. 
Published: September 2004

AbstractThe hyaline layer (HL) is an apically located extracellular matrix (ECM) which surrounds the sea urchin embryo from the time of fertilization until metamorphosis occurs. While gelatin‐cleavage activities were absent from freshly prepared hyaline layers, a dynamic pattern of activities developed in layers incubated at 15 or 37°C in Millipore‐filtered sea water (MFSW). Cleavage activities at 90, 55, 41, and 32 kDa were evident following incubation at either temperature. The activation pathway leading to the appearance of these species was examined to determine the minimum salt conditions required for processing and to establish precursor–product relationships. In both qualitative and quantitative assays, the purified 55 kDa gelatinase activity was inhibited by 1,10‐phenanthroline (a zinc‐specific chelator) and ethylenebis (oxyethylenenitrilo) tetraacetic acid (EGTA). Calcium reconstituted the activity of the EGTA‐inhibited enzyme with an apparent dissociation constant (calcium) of 1.2 mM. Developmental substrate gel analysis was performed using various stage embryos. The 55 and 32 kDa species comigrated with gelatin‐cleavage activities present in sea urchin embryos. Collectively, the results reported here document a zymogen activation pathway which generates a 55 kDa, gelatin‐cleaving activity within the extraembryonic HL. This species displayed characteristics of the matrix metalloproteinase class of ECM modifying enzymes. © 2004 Wiley‐Liss, Inc.
Transcriptional activities of mutant p53: When mutations are more than a loss
Authors: Kim Ella , Deppert Wolfgang 
Published: September 2004

AbstractThe dominant oncogenic properties of mutant p53 have been recognized as a phenomenon associated with tumor progression a long time ago, even before it was realized that the major function of wild type p53 is that of a tumor suppressor. Recent advances in this fascinating area in tumor cell biology reveal that the community of mutant p53 proteins is comprised of proteins that are extremely diverse both structurally and functionally, and elicit a multitude of cellular responses that not only are entirely distinct from those mediated by wild type p53, but also vary among different mutant p53 proteins. Aberrant regulation of transcription is one of the mechanisms underlying the ability of some mutant p53 proteins to act as oncogenic factors. Systematic analyses of the transcriptional activities of mutant p53 suggest that not the loss of transcriptional activity as such, but alterations of target DNA selectivity may be the driving force of mutant p53 specific transcription underlying the growth‐promoting effects of mutant p53. This article focuses on mechanistic aspects of mutp53 “gain‐of‐function” with the emphasis on possible mechanisms underlying transcriptional activation by mutp53. © 2004 Wiley‐Liss, Inc.
Osmoregulatory action of 17β‐estradiol in the gilthead sea bream Sparus auratus
Authors: Guzmán José María , Sangiao‐Alvarellos Susana , Laiz‐Carrión Raúl , Míguez Jesús M. , Martín Del Río María Del Pilar , Soengas José Luis , Mancera Juan Miguel 
Published: September 2004

AbstractThe osmoregulatory action of 17β‐estradiol (E2) was examined in the euryhaline teleost Sparus auratas. In a first set of experiments, fish were injected once with vegetable oil containing E2 (1, 2 and 5 µg/g body weight), transferred 12h after injection from sea water (SW, 38 ppt salinity) to hypersaline water (HSW, 55 ppt) or to brackish water (BW, 5 ppt salinity) and sampled 12h later (i.e. 24 h post‐injection). In a second experiment, fish were injected intraperitoneally with coconut oil alone or containing E2 (10 µg/g body weight) and sampled after 5 days. In the same experiment, after 5 days of treatment, fish of each group were transferred to HSW, BW and SW and sampled 4 days later (9 days post‐implant). Gill Na+,K+‐ATPase activity, plasma E2 levels, plasma osmolality, and plasma levels of ions (sodium and calcium), glucose, lactate, protein, triglyceride, and hepatosomatic index were examined. Transfer from SW to HSW produced no significant effects on any parameters assessed. E2 treatment did not affect any parameter. Transfer from SW to BW resulted in a significant decrease in plasma osmolality and plasma sodium but did not affect gill Na+,K+‐ATPase activity. A single dose of E2 attenuated the decrease in these parameters after transfer from SW to BW, but was without effect on gill Na+,K+‐ATPase activity. An implant of E2 (10 µg/g body weight) for 5 days significantly increased plasma calcium, hepatosomatic index, plasma metabolic parameters, and gill Na+,K+‐ATPase activity. In coconut oil‐implanted (sham) fish, transfer from SW to HSW or BW during 4 days significantly elevated gill Na+,K+‐ATPase. Gill Na+,K+‐ATPase activity remained unaltered after transfer of E2‐treated fish to HSW or BW. However, in E2‐treated fish transferred from SW to SW (9 days in SW after E2‐implant), gill Na+,K+‐ATPase activity decreased with respect to HSW‐ or BW‐transferred fish. Shams transferred to HSW showed increased levels of lactate, protein, and trygliceride in plasma, while those transferred to BW only displayed increased trygliceride levels. E2‐treated fish transferred to HSW showed higher protein levels without any change in other plasmatic parameters, while those transferred to BW displayed elevated plasma glucose levels but decreased osmolality and protein levels. These results substantiate a chronic stimulatory action of E2 on gill Na+,K+‐ATPase activity in the euryhaline teleost Sparus auratas. J. Exp. Zool. 301A:828–836, 2004. © 2004 Wiley‐Liss, Inc.
Cross communication between signaling pathways: Juvenoid hormones modulate ecdysteroid activity in a crustacean
Authors: Mu Xueyan , Leblanc Gerald A. 
Published: September 2004

AbstractMethyl farnesoate is a juvenoid hormone that regulates a variety of processes in crustaceans including male sex determination among daphnids (Branchiopoda, Cladocera). The synthetic juvenoids pyriproxyfen and fenoxycarb mimic the action of methyl farnesoate in daphnids. In the present study we tested the hypothesis that juvenoids also can regulate ecdysteroid activity in a crustacean (Daphnia magna). Methyl farnesoate, pyriproxyfen, and fenoxycarb all disrupted ecdysteroid‐regulated aspects of embryo development in daphnids. Exposure of ecdysteroid‐responsive cells to 20‐hydroxyecdysone reduced cell proliferation and increased mRNA levels of the ecdysone receptor and its partner protein ultraspiracle. Co‐treatment of cells with the juvenoid pyriproxyfen attenuated all of these ecdysteroid mediated responses. While juvenoids functioned as anti‐ecdysteroids in both intact embryos and in cultured cells, 20‐hydroxyecdysone showed no evidence of acting as an anti‐juvenoid. The combined effects of pyroproxyfen with the ecdysteroid synthesis inhibitor fenarimol and the ecdysteroid receptor antagonist testosterone were evaluated in an effort to discern whether the action of the juvenoids were additive with those of know anti‐ecdysteroids. The anti‐ecdysteroid effects of pyriproxyfen were non‐additive with those of either anti‐ecdysteroid. Rather, joint effects conformed to a model of synergy. These results demonstrated that juvenoids elicit anti‐ecdysteroidal activity in a crustacean through a unique mechanism of action. A model involving receptor partner deprivation is proposed that explains the synergistic interactions observed. J. Exp. Zool. 301A:793–801, 2004. © 2004 Wiley‐Liss, Inc.
Perception and possible utilization of moonlight intensity for reproductive activities in a lunar‐synchronized spawner, the golden rabbitfish
Authors: Takemura Akihiro , Susilo Endang Sri , Rahman M.D. Saydur , Morita Masaya 
Published: September 2004

AbstractRabbitfishes are known to spawn synchronously around the species‐specific lunar phase. It is considered that they perceive and utilize cues from the moon in order to be synchronized gonadal development and spawning with the lunar cycle. Using the golden rabbitfish, Siganus guttatus, which spawns synchronously around the first quarter moon during the reproductive season, we measured the fluctuation of melatonin levels and examined the response of the fish to moonlight intensity. Daily fluctuation of melatonin concentration in the blood of golden rabbitfish showed low levels during daytime and high levels during night‐time, suggesting that melatonin functions in the perception and utilization of photoperiod. Plasma melatonin concentration at the new moon was higher than that at the full moon. When the fish were exposed to moonlight at midnight of the both moon phases, the melatonin concentrations decreased to the control levels. These results show that the fish possibly perceive moonlight intensity and plasma melatonin fluctuates according to ‘lightness’ at a point of night. At the first spawning period (experiment was started one month before the spawning), the fish reared under natural conditions spawned at the expected spawning dates, whereas the fish reared under the constant darkness and lightness of night did not spawn. At the second spawning period (experiment was started 2 weeks before the spawning), the fish reared under the conditions of natural and constant darkness of night spawned but not that of constant lightness of night. It is possible that night conditions are related to synchronous gonadal development and spawning in the golden rabbitfish. J. Exp. Zool. 301A:844–851, 2004. © 2004 Wiley‐Liss, Inc.
Molecular characterization of a cDNA encoding vitellogenin in the coonstriped shrimp, Pandalus hypsinotus and site of vitellogenin mRNA expression
Authors: Tsutsui Naoaki , Saido‐Sakanaka Hisako , Yang Wei‐Jun , Jayasankar Vidya , Jasmani Safiah , Okuno Atsuro , Ohira Tsuyoshi , Okumura Takuji , Aida Katsumi , Wilder Marcy N. 
Published: September 2004

AbstractIn order to determine the primary structure of vitellogenin in a protandric species, the coonstriped shrimp Pandalus hypsinotus, we previously purified four vitellin components (designated as VnA, VnB, VnC, and VnD, respectively), and chemically analyzed their partial amino acid sequences. In this study, we subsequently cloned a cDNA encoding vitellogenin in this species based on the N‐terminal and internal amino acid sequences of VnA, as well as the N‐terminal sequence of VnC. The open reading frame of this cDNA encoded a pro‐vitellogenin in which vitellins were arranged as follows: NH2–VnA–VnB–VnC/D–COOH. The deduced amino acid sequence possessed a single consensus cleavage sequence, R–X–K/R–R, along the lines of vitellogenins reported in other crustaceans and insects, and the N‐terminal sequence of VnB was immediately preceded by this sequence. The comparison of primary structures revealed the existence of a basic and characteristic structure for the vitellogenin molecule in decapod crustacean species, and phylogenetic analysis reflected the current taxonomic classifications of Crustacea. An approximately 8 kb‐long transcript of the vitellogenin gene was detected in the hepatopancreas of female shrimps having a gonadosomatic index higher than 1.0 by Northern blot analysis, but was not observed in the hepatopancreas and gonads of male shrimps and the hepatopancreas of female shrimps having a gonadosomatic index lower than 1.0. These results indicate that the hepatopancreas is responsible for vitellogenin synthesis. J. Exp. Zool. 301A:802–814, 2004. © 2004 Wiley‐Liss, Inc.
Application of RNA interference to chicken embryos using small interfering RNA
Authors: Sato Fuminori , Nakagawa Tetsuto , Ito Makoto , Kitagawa Yasuo , Hattori Masa‐aki 
Published: September 2004

AbstractGene silencing using small interfering RNA (siRNA) is not established in avian species. The present study was performed to evaluate RNA interference (RNAi) in the chicken embryo by using a dual fluorescence reporter assay, a plasmid encoding green fluorescent protein (GFP) and a plasmid encoding red fluorescent protein (RFP). The siRNA targeting the GFP mRNA sequence (GFP‐siRNA) with both plasmids was introduced into cultured cells and whole embryos by lipofection and microelectroporation, respectively. GFP‐ and RFP‐expressed cells and embryos were observed under fluorescent microscopy and analyzed by flow cytometer, and their mRNAs were analyzed by reverse transcription‐PCR (RT‐PCR). The strong fluorescence was observed by introducing both plasmids into cells. The intensity of the green fluorescence generated by GFP was greatly suppressed by introducing GFP‐siRNA. RT‐PCR analysis showed that introducing GFP‐siRNA also decreased GFP mRNA levels. In contrast to GFP, the intensity of the red fluorescence generated by RFP and the RFP mRNA levels remained unchanged. In whole embryos, also, introducing GFP‐siRNA specifically suppressed GFP expression, and the suppression was maintained for at least 72 h. Consequently, it was concluded that the gene silencing using siRNA is applicable to analyzing the function of genes of interest during avian embryogenesis. J. Exp. Zool. 301A:820–827, 2004. © 2004 Wiley‐Liss, Inc.
Histopathologic changes induced by the microtubule‐stabilizing agent Taxol in the rat hippocampus in vivo
Authors: Mercado‐Gómez Octavio , Ferrera Patricia , Arias Clorinda 
Published: September 2004

AbstractMicrotubules and their associated proteins play a prominent role in neuronal morphology, axonal transport, neuronal plasticity, and neuronal degeneration. It has been proposed that microtubule damage is sufficient to induce neuronal death. In this regard, the microtubule‐stabilizing agent Taxol could be a useful tool to reproduce some aspects of neurodegenerative diseases associated with disturbances of the cytoskeleton and alterations in axonal transport. Although differential effects of Taxol on neuronal viability have been found in vitro, Taxol toxicity in the central nervous system remains to be addressed. We studied the effects of Taxol on neuronal morphology and viability as well as changes in microtubule‐associated proteins MAP2 and tau in rat hippocampus. Our results show that Taxol induces dose‐dependent neuronal death accompanied by the loss of MAP2 and the presence of dystrophic neurites. Interestingly paired helical filament (PHF)‐1 immunoreactivity, which is associated with a phosphorylated epitope of tau proteins, was induced in the damaged hippocampus. Our results suggest that microtubule dynamics have a role in maintenance of neuronal morphology and survival in vivo, and that modifications in microtubule dynamics, may alter the content and neuronal distribution of MAP2 and promote alterations in the phosphorylation state of tau. © 2004 Wiley‐Liss, Inc.
Structure determination of ramosine, a guaianolide, by NMR spectroscopy
Authors: Khan Sher Bahadar , Afza Nighat , Malik Abdul , ul Haq Azhar , Ahmed Zaheer 
Published: September 2004

AbstractRamosine, a new sesquiterpene lactone, was isolated from the chloroform fraction of Amberboa ramosa and the structure was assigned as 4β‐(hydroxymethyl)‐3β,4α‐dihydroxy‐8α‐[(S)‐3‐hydroxy‐2‐ethylenepropionyloxy]‐1αH, 5αH,6βH,7αH,11βH,11α‐methylguaia‐10(14)‐en‐6, 12‐olide by extensive NMR studies. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and NMR spectroscopic studies of allylsulfanyl‐N1‐alkyl‐N4‐phenyl‐1,4‐phenylenediamines and their cyclization products, 2,3‐dihydro‐1‐benzothiophenes and thiochromans
Authors: Katritzky Alan R. , Akhmedov Novruz G. , Wang Mingyi , Rostek Charles J. , Steel Peter J. 
Published: September 2004

AbstractRegioselective addition of allylthiol at the C‐3 position adjacent to the nitrogen carrying the phenyl group of the 1,4‐phenylenediamine moiety of compounds 1–4 was rigorously confirmed by 1D NOE difference in combination with gHMBC experiments. The structures of 1,4‐phenylenediamines 1–4, allylsulfanyl‐N1‐alkyl‐N4‐phenyl‐1,4‐phenylenediamines 5–8 and cyclization products 9–14 were completely analyzed in both CDCl3 and DMSO‐d6 solutions. The 1H and 13C NMR spectra of 10 and 11, which contain two chiral centers, exhibit duplication for several signals, indicating the existence of two diastereomeric forms. The full structures of 5 and 9 were unambiguously confirmed by x‐ray crystallography. The 1H and 13C NMR spectra of all compounds were assigned using one‐ and two‐dimensional NMR techniques (APT, DEPT, 1D NOE difference, COSY, NOESY, HETCOR, gHMQC and gHMBC). Copyright © 2004 John Wiley & Sons, Ltd.
51V magic angle spinning NMR in VOPO4 phases
Authors: Siegel Renée , Dupré Nicolas , Quarton Michel , Hirschinger Jérôme 
Published: September 2004

Abstract51V magic angle spinning NMR was applied to the αII, β and γ phases of VOPO4 at three magnetic field strengths (4.7, 7.1, and 11.7 T). The 51V quadrupole and chemical shift tensors were determined by iterative fitting of the NMR lineshapes at the three magnetic field strengths. The applicability of the method is illustrated by comparison with literature data. Although determined chemical shift tensors are completely axially symmetric and of the same magnitude, all studied phases can clearly be distinguished by their quadrupole coupling tensor. Relationships between the 51V NMR data and structural characteristics such as crystal symmetries are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
High‐resolution solid‐state 73Ge NMR spectra of hexacoordinated germanium compounds
Authors: Takeuchi Yoshito , Nishikawa Miki , Yamamoto Hiroshi 
Published: September 2004

AbstractHigh‐resolution solid‐state magic angle spinning 73Ge NMR spectra of hexavalent germanium compounds, i.e. diiodogermylene (1a) and bis(1‐pyrrolyl)(meso‐tetraphenylporphyrinato)germanium (3a), were determined. To the best of our knowledge, this is the first example of high‐resolution solid‐state 73Ge NMR spectra of hexacoordinated germanium nuclei. The symmetry requirement for observation of high‐resolution solid‐state 73Ge NMR spectra is discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Creatinine and creatininium cation in DMSO‐d6 solution. Structure and restricted internal rotation of NH2 group
Authors: Kotsyubynskyy Dmytro , Molchanov Sergey , Gryff‐Keller Adam 
Published: September 2004

AbstractInvestigation of 15N NMR spectra of isotopically enriched creatinine has unequivocally shown that in DMSO‐d6 solution it exists as amino tautomer (2‐amino‐1‐methylimidazoline‐4‐one), which in the presence of acid is protonated at N‐3. Free energies of activation of the amino group rotation in creatinine and its cation have been determined to be 56 kJ/mol and 60 kJ/mol, respectively, at 298 K, by performing the simultaneous analysis of the lineshapes of NH2 proton signals in the whole set of 1H NMR spectra recorded at various temperatures and magnetic fields. These results have been theoretically reproduced by the calculations of molecular structures and energies of creatinine and creatininium cation in their ground states and transition states of the amino group rotation, using DFT (B3LYP) method, involving the influence of the solvent. Copyright © 2004 John Wiley & Sons, Ltd.
1H chemical shifts in NMR. Part 21—Prediction of the 1H chemical shifts of molecules containing the ester group: a modelling and ab initio investigation
Authors: Abraham Raymond J. , Bardsley Ben , Mobli Mehdi , Smith Richard J. 
Published: September 2004

AbstractThe 1H NMR spectra of 24 compounds containing the ester group are given and assigned. These data were used to investigate the effect of the ester group on the 1H chemical shifts in these molecules. These effects were analysed using the CHARGE model, which incorporates the electric field, magnetic anisotropy and steric effects of the functional group for long‐range protons together with functions for the calculation of the two‐ and three‐bond effects. The effect of the ester electric field was given by considering the partial atomic charges on the three atoms of the ester group. The anisotropy of the carbonyl group was reproduced with an asymmetric magnetic anisotropy acting at the midpoint of the carbonyl bond with values of Δχparl and Δχperp of 10.1 × 10−30 and −17.1 × 10−30 cm3 molecule−1. An aromatic ring current (=0.3 times the benzene ring current) was found to be necessary for pyrone but none for maleic anhydride. This result was confirmed by GIAO calculations. The observed 1H chemical shifts in the above compounds were compared with those calculated by CHARGE and the ab initio GIAO method (B3LYP/6–31G**). For the 24 compounds investigated with 150 1H chemical shifts spanning a range of ca 10 ppm, the CHARGE model gave an excellent r.m.s. error (obs − calc) of <0.1 ppm. The GIAO calculations gave a very reasonable r.m.s. error of ca 0.2 ppm although larger deviations of ca 0.5 ppm were observed for protons near to the electronegative atoms. The accurate predictions of the 1H chemical shifts given by the CHARGE model were used in the conformational analysis of the vinyl esters methyl acrylate and methyl crotonate. An illustration of the use of the CHARGE model in the prediction of the 1H spectrum of a complex organic molecule (benzochromen‐6‐one) is also given. Copyright © 2004 John Wiley & Sons, Ltd.
Towards the automatic analysis of 1H NMR spectra: Part 4—Additional requirements of flow‐NMR
Authors: Griffiths Lee , Horton Rob 
Published: September 2004

AbstractFlow‐NMR allows more rapid and convenient acquisition of NMR spectra. Its main application area has therefore been in multiple parallel synthesis or combinatorial chemistry. At the same time, there is a significant need to automate the analysis of the resultant spectra. However, flow‐NMR brings spectral imperfections, which compromise attempts to automate this analysis. This study proposes experimental and computational expedients to accommodate the effects of residual solvent peaks, 13C satellites, finite signal‐to‐noise ratio, impurities, presaturation on integral calculations, the ‘silent’ region and how multiplet areas can be scaled to numbers of protons in this environment. Copyright © 2004 John Wiley & Sons, Ltd.