bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hairpin dsRNA does not trigger RNA interference in Candida albicans cells
Authors: Staab Janet F. , White Theodore C. , Marr Kieren A. 
Published: August 2010

AbstractRNA interference/silencing mechanisms triggered by double‐stranded RNA (dsRNA) have been described in many eukaryotes, including fungi. These mechanisms have in common small RNA molecules (siRNAs or microRNAs) originating from dsRNAs that, together with the effector protein Argonaute, mediate silencing. The genome of the fungal pathogen Candida albicans harbours a well‐conserved Argonaute and a non‐canonical Dicer, essential members of silencing pathways. Prototypical siRNAs are detected as members of the C. albicans transcriptome, which is potential evidence of RNA interference/silencing pathways in this organism. Surprisingly, expression of a dsRNA a hairpin ADE2 dsRNA molecule to interfere with the endogenous ADE2 mRNA did not result in down‐regulation of the message or produce adenine auxotrophic strains. Cell free assays showed that the hairpin dsRNA was a substrate for the putative C. albicans Dicer, discounting the possibility that the nature of the dsRNA trigger affects silencing functionality. Our results suggested that unknown cellular events govern the functionality of siRNAs originating from transgenes in RNA interference/silencing pathways in C. albicans. Copyright © 2010 John Wiley & Sons, Ltd.
Novel episomal vectors and a highly efficient transformation procedure for the fission yeast Schizosaccharomyces japonicus
Authors: Aoki Keita , Nakajima Reiko , Furuya Kanji , Niki Hironori 
Published: August 2010

AbstractSchizosaccharomyces japonicus is a fission yeast for which new genetic tools have recently been developed. Here, we report novel plasmid vectors with high transformation efficiency and an electroporation method for Sz. japonicus. We isolated 44 replicating segments from 12 166 transformants of Sz. japonicus genomic fragments and found a chromosomal fragment, RS1, as a new replicating sequence that conferred high transformation activity to Sz. japonicus cells. This sequence was cloned into a pUC19 vector with ura4+ of Sz. pombe (pSJU11) or the kan gene on the kanMX6 module (pSJK11) as selection markers. These plasmids transformed Sz. japonicus cells in the early‐log phase by electroporation at a frequency of 123 cfu/µg for pSJK11 and 301 cfu/µg for pSJU11, which were higher than previously reported autonomously replicating sequences. Although a portion of plasmids remained in host cells by integration into the chromosome via RS1 segment, the plasmids could be recovered from transformants. The plasmid copy number was estimated to be 1.88 copies per cell by Southern blot analysis using a Sz. pombe ura4+ probe. The plasmid containing ade6+ suppressed the auxotrophic growth of the ade6‐domE mutant, indicating that the plasmid would be useful for suppressor screening and complementation assays in Sz. japonicus. Furthermore, pSJU11 transformed Sz. pombe cells with the same frequency as the pREP2 plasmid. This study is a report to demonstrate practical use of episomal plasmid vectors for genetic research in Sz. japonicus. RS1 has been submitted to the DDBJ/EMBL/GenBank database (Accession No. AB547343). Copyright © 2010 John Wiley & Sons, Ltd.
Slt2 MAPK pathway is essential for cell integrity in the presence of arsenate
Authors: Matia‐González Ana M. , Rodríguez‐Gabriel Miguel A. 
Published: August 2010

AbstractArsenate is a common toxic metalloid found in drinking water worldwide that causes several human diseases. The biochemical action underlying cellular response to arsenate, however, is not yet completely understood. Here we used Saccharomyces cerevisiae as an eukaryotic model system to identify proteins essential for adaptation to arsenate treatment. Previous studies have demonstrated a function for Hog1 MAPK in modulating the cellular response to arsenite. Our results, however, showed that cells deficient in Hog1 did not show increased sensitivity to arsenate, suggesting that perhaps other MAPKs may be involved in the response to this particular arsenic species. Here, we found that Slt2 MAPK and several of its upstream regulators are essential in modulating the response to arsenate, and that Slt2 is phosphorylated after arsenate treatment. Furthermore, whole‐genome transcriptional analysis showed that Slt2 is required for the induction of several genes in response to arsenate exposure. Many of these genes are involved in the cellular response to heat, suggesting an overlap between these two stress response pathways, and pointing toward a common response to both arsenate and heat exposure in Saccharomyces cerevisiae. Furthermore, our results support the idea that cellular exposure to arsenate results in induction of cellular signalling pathways different from those induced under arsenite treatment. Copyright © 2010 John Wiley & Sons, Ltd.
Requirement of glutathione for Sod1 activation during lifespan extension
Authors: Mannarino Sérgio C. , Vilela Leonardo F. , Brasil Aline A. , Aranha Juliana N. , Moradas‐Ferreira Pedro , Pereira Marcos D. , Costa Vítor , Eleutherio Elis C. A. 
Published: August 2010

AbstractIt has been shown that the activation of cytosolic superoxide dismutase (Sod1) in Saccharomyces cerevisiae is only dependent on Ccs1, which is responsible for insertion of copper into the enzyme catalytic center, and that glutathione (GSH) is not necessary for this process. In this work, we addressed an important role of GSH in Sod1 activation by a Ccs1‐dependent mechanism during oxidative stress and its role in yeast lifespan. Exponential cells of Saccharomyces cerevisiae, treated or not with 0.5 mM menadione for 1 h, were used for evaluation of the effect of a mild oxidative stress pre‐treatment on chronological lifespan. The results showed that menadione induced a lifespan extension in the wild‐type (WT) strain but this adaptive response was repressed in gsh1 and in sod1 strains. Interestingly, menadione treatment increased SOD1 and CCS1 gene expression in both WT and gsh1 strains. However, while these strains showed the same Sod1 activity before treatment, only the WT presented an increase of Sod1 activity after menadione exposure. Glutathionylation seems to be essential for Sod1 activation since no increase in activity was observed after menadione treatment in grx1 and grx2 null mutants. Our results suggest that GSH and glutathionylation are fundamental to protect Sod1 sulfhydryl residues under mild oxidative stress, enabling Sod1 activation and lifespan extension. Copyright © 2010 John Wiley & Sons, Ltd.
2,4‐Dimethylpentadienyl‐Komplexe des Neodyms, Lanthans und Yttriums als Präkatalysatoren für die stereoselektive Butadienpolymerisation
Authors: Kunze Michael R. , Taube Rudolf 
Published: August 2010

AbstractTo extend the investigation of the applicability of 2,4‐dimethylpentadienyl rare earth metal complexes as precatalysts for stereoselective butadiene polymerization, a selection of new neodymium, lanthanum, and yttrium complexes were previously supplied with detailed structural characterization. We report herein our observations on the catalytically nature of 2,4‐dimethylpentadienyl rare earth metal complexes. Under standard conditions the complexes are catalytically inactive. In order to successfully activate the coordinatively saturated complexes, aluminium trialkyls AlMe3, AlEt3, and Al(iBu)3, aluminoxanes methylaluminoxane (MAO), hexaisobuthylaluminoxane (HiBAO), and modified methylaluminoxane with an Al(iBu)3 additive (MMAO) and diethylaluminium bromide were employed as cocatalysts. The actual catalyst is believed to be a soluble mono(2,4‐dimethylpentadienyl)neodymium(III) dianion complex, through which an insertion of 1,3‐butadiene in the pentadienyl‐neodymium(III) bond causes the catalysis of the chain growth to be initiated. From these investigations a substantial further insight into the chemistry of (2,4‐dimethylpentadienyl)lanthanide(III) complexes was gained and the special applicability of the neodymium complexes for the preparation of highly active catalyst for the 1,4‐cis‐polymerization of 1,3‐butadienes was demonstrated.
Synthesis, Crystal Structures, and Thermal Properties of New Zinc(II) Thiocyanato Coordination Compounds
Authors: Bhosekar Gaurav , Boeckmann Jan , Jeß Inke , Näther Christian 
Published: August 2010

AbstractReaction of zinc(II) thiocyanate with pyrazine, pyrimidine, pyridazine, and pyridine leads to the formation of new zinc(II) thiocyanato coordination compounds. In bis(isothiocyanato‐N)‐bis(μ2‐pyrazine‐N,N) zinc(II) (1) and bis(isothiocyanato‐N)‐bis(μ2‐pyrimidine‐N,N) zinc(II) (2) the zinc atoms are coordinated by four nitrogen atoms of the diazine ligands and two nitrogen atoms of the isothiocyanato anions within slightly distorted octahedra. The zinc atoms are connected by the diazine ligands into layers, which are further linked by weak intermolecular S···S interactions in 1 and by weak intermolecular C–H···S hydrogen bonding in 2. In bis(isothiocyanato‐N)‐bis(pyridazine‐N) (3) discrete complexes are found, in which the zinc atoms are coordinated by two nitrogen atoms of the isothiocyanato ligands and two nitrogen atoms of the pyridazine ligands. The crystal structure of bis(isothiocyanato‐N)‐tetrakis(pyridine‐N) (4) is known and consists of discrete complexes, in which the zinc atoms are octahedrally coordinated by two thiocyanato anions and four pyridine molecules. Investigations using simultaneous differential thermoanalysis and thermogravimetry, X‐ray powder diffraction and IR spectroscopy prove that on heating, the ligand‐rich compounds 1, 2, and 3 decompose without the formation of ligand‐deficient intermediate phases. In contrast, compound 4 looses the pyridine ligands in two different steps, leading to the formation of the literature known ligand‐deficient compound bis(isothiocyanato‐N)‐bis(pyridine‐N) (5) as an intermediate. The crystal structure of compound 5 consists of tetrahedrally coordinated zinc atoms which are surrounded by two isothiocyanato anions and two pyridine ligands. The structures and the thermal reactivity are discussed and compared with this of related transition metal isothiocyanates with pyrazine, pyrimidine, pyridazine, and pyridine.
Methane Storage in Prussian Blue Analogues and Related Porous Solids: Nature of the Involved Adsorption Forces
Authors: Zamora Blanca , Roque Jorge , Balmaseda Jorge , Reguera Edilso 
Published: August 2010

AbstractMethane adsorption is possible through three types of interactions: (1) dispersive forces (van der Waals type); (2) polarization of its electron cloud by a positive charge center; (3) induced quadrupole moment by perturbation of the molecule electron cloud through the polarization interaction. This induced quadrupole moment is able to interact with the local electric field gradient. Porous Prussian blue analogues and related zeolite‐like zinc hexacyanometallates appear to have unique features for the evaluation of the relative importance of these adsorption forces for the methane storage in molecular porous materials. Methane adsorption isotherms for T3[Co(CN)6]2 (T = Mn, Co, Ni, Cu, Zn, Cd) and Zn3A2[Fe(CN)6]2 (A = Na, K, Rb, Cs) were recorded and interpreted. From the obtained adsorption data information on the relative contribution of both electrostatic and dispersive interactions to the adsorption forces was obtained.
Supramolecular Architectures of Four New Transition Metal Complexes with 3‐[4‐(Carboxymethoxy)phenyl]propanoic Acid and N‐[4‐(Carboxymethoxy)phenyl]iminodiacetic Acid
Authors: Liu Chong‐Bo , Wen Hui‐Liang , Gong Yun‐Nan , Liu Xiao‐Ming , Tan Sheng‐Shui 
Published: August 2010

AbstractFour new transition metal complexes: [Cu(Hcppa)2(H2O)2] (1), [Co2(cppa)2(H2O)10] (2), [Co3(cpia)2(H2O)8]·2H2O (3) and [Ni3(cpia)2(H2O)12]·6H2O (4) {H2cppa = 3‐(4‐(carboxymethoxy)phenyl]propanoic acid; H3cpia = N‐[4‐(carboxymethoxy)phenyl]iminodiacetic acid} were synthesized and characterized. Complexes 1 and 2 show mononuclear structures, complexes 3 and 4 exhibit dinuclear structures. All complexes extend to 3D supramolecular networks through hydrogen bonds, of which complexes 3 and 4 display microporous structures. In complexes 2–4 the water clusters are trapped by the cooperative association of coordinate interactions as well as hydrogen bonds, forming different 1D metal‐water chain structures. Thermal stabilities of complexes 1–4 were discussed.
Stannocene as Cyclopentadienyl Transfer Agent in Transmetalation Reactions with Lanthanide Metals for the Synthesis of Tris(cyclopentadienyl)lanthanides
Authors: Janiak Christoph 
Published: August 2010

AbstractTransmetalation of the lanthanide metals samarium and ytterbium with bis(cyclopentadienyl)tin(II), stannocene, (η5‐C5H5)2Sn as cyclopentadienyl transfer agent yields the tris(cyclopentadienyl)lanthanides (η5‐C5H5)3Ln (in toluene), (η5‐C5H5)3Ln·THF (Ln = Sm, Yb) and bis(cyclopentadienyl)ytterbium, (η5‐C5H5)2Yb·THF in a direct, facile, high‐yield and halide‐free route. In toluene the base‐free forms (η5‐C5H5)3Ln are isolated directly. In THF the adducts (η5‐C5H5)3Ln·THF are obtained in crystalline form. At a 1:1 molar ratio of Yb:Sn the ytterbium metal reduces the initially formed (η5‐C5H5)3Yb·THF to (η5‐C5H5)2Yb·THF.
Manganese‐σ‐Borane Complexes from Dihaloboranes
Authors: Braunschweig Holger , Kraft Katharina , Kupfer Thomas , Siedler Eva 
Published: August 2010

AbstractThe hydride complex K[(η5‐C5H5)Mn(CO)2H] reacted with a range of dihalo(organyl)boranes X2BR (X = Cl, Br; R = tBu,Mes, Ferrocenyl) to give the corresponding borane complexes[(η5‐C5H5)Mn(CO)2(HB(X)R)]., The presence of a hydride in bridging position between manganese and boron was deduced from 11B decoupled 1H NMR spectra. Additionally, the structure of the tert‐butyl borane complex was confirmed by single‐crystal X‐ray diffraction.
Solvothermal Synthesis of New Luminescent Zinc(II) Coordination Polymers with One‐Dimensional Homochiral Structures
Authors: Duan Yulai , Lin Zhien , Stips Tobias , Dehnen Stefanie 
Published: August 2010

AbstractBy using a dual‐ligand approach, two new homochiral zinc(II) coordination polymers, Zn2(phen)2(H2O)2(cam)2·ethanol (1) and Zn(bipy)(cam) (2) [phen = 1,10‐phenanthroline, bipy = 2,2′‐bipyridine, H2cam = (1R,3S)‐(+)‐camphoric acid] have been synthesized under solvothermal conditions. Compound 1 has a zigzag chain‐like structure and compound 2 has a linear chain‐like structure. The two compounds exhibit intense photoluminescence upon photoexcitation at 280 and 290 nm, respectively.
Effect of the Length of Fatty Acid Ligands on Lead(II) Complexes Based on a 1,10‐Phenanthroline Derivative
Authors: Wang Xiu‐Li , Gao Qiang , Chen Yong‐Qiang , Liu Guo‐Cheng , Tian Ai‐Xiang , Kang Zhen‐Hui 
Published: August 2010

AbstractTwo new PbII metal‐organic coordination polymers [Pb(3‐pdip)(glu)]·H2O (1) and [Pb(3‐pdip)2(odc)]·2H2O (2) [3‐pdip = 2‐(3‐pyridine)imidazo[4,5‐f]1,10‐ phenanthroline, H2glu = glutaric acid, H2odc = octanedioic acid], were synthesized by hydrothermal reactions of varying fatty acid ligands, and structurally characterized by single‐crystal X‐ray diffraction. Complex 1 exhibits a one dimensional (1D) chain structure, in which 3‐pdip ligands are attached to one side of the 1D chain. Complex 2 exhibits also a 1D chain structure, in which some paired 3‐pdip ligands are affiliated on both sides of the 1D chain. In the title complexes, the π–π stacking and hydrogen‐bonding interactions extend the 1D chain into a 3D supramolecular framework, respectively. The structural differences between the title complexes indicate the importance of fatty acid length for the creation of molecular architectures. Moreover, the thermal and fluorescence properties of title complexes are also reported.
Progress in the Compilation of an Oxovanada‐Silsesquioxane Portfolio and Catalytic Activity of Organometallic Representatives in Ethylene Polymerisation
Authors: Ohde Christian , Limberg Christian , Schmidt Dennis , Enders Markus , Demeshko Serhiy , Knispel Christina 
Published: August 2010

AbstractEmploying various incompletely condensed silsesquioxanes as ligand precursors in reactions with simple oxovanadates a variety of oxovanadium silsequioxanes could be synthesised, that might be regarded as models for oxovanadium units on silica surfaces. These include a tetranuclear vanadium(IV) compound as well as two complexes where O2V+ units are coordinated to two siloxide functions as part of a silsesquioxane framework. Moreover, compounds containing Cp*V(O)2+ moieties were prepared, whose activities as polymerisation procatalysts were examined: They turned out to be moderately active for the polymerisation of ethylene. All compounds were fully characterised, in case of the tetranuclear vanadium(IV) complex this also includes the investigation of the magnetic behaviour. Moreover, for two complexes also the molecular structures could be determined with sufficient quality by X‐ray diffraction.
Prolonged Antibiotic Treatment does not Prevent Intra‐Abdominal Abscesses in Perforated Appendicitis
Authors: van Wijck K. , de Jong J. R. , van Heurn L. W. E. , van der Zee D. C. 
Published: August 2010

AbstractBackgroundChildren with perforated appendicitis have a relatively high risk of intra‐abdominal abscesses. There is no evidence that prolonged antibiotic treatment after surgery reduces intra‐abdominal abscess formation. We compared two patient groups with perforated appendicitis with different postoperative antibiotic treatment protocols.MethodsWe retrospectively reviewed patients younger than age 18 years who underwent appendectomy for perforated appendicitis at two academic hospitals between January 1992 and December 2006. Perforation was diagnosed during surgery and confirmed during histopathological evaluation. Patients in hospital A received 5 days of antibiotics postoperatively, unless decided otherwise on clinical grounds. Patients in hospital B received antibiotics for 5 days, continued until serum C‐reactive protein(CRP) was <20 mg/l. Univariate logistic regression analysis was performed on intention‐to‐treat basis. p < 0.05 was considered significant.ResultsA total of 149 children underwent appendectomy for perforated appendicitis: 68 in hospital A, and 81 in hospital B. As expected, the median (range) use of antibiotics was significantly different: 5 (range, 1–16) and 7 (range, 2–32) days, respectively (p < 0.0001). However, the incidence of postoperative intra‐abdominal abscesses was similar (p = 0.95). Regression analysis demonstrated that sex (female) was a risk factor for abscess formation, whereas surgical technique and young age were not.ConclusionsProlonged use of antibiotics after surgery for perforated appendicitis in children based on serum CRP does not reduce postoperative abscess formation.
The effects of serotiny and rainfall‐cued dispersal on fitness: bet‐hedging in the threatened cactus Mammillaria pectinifera
Authors: Peters Edward M. , Martorell Carlos , Ezcurra Exequiel 
Published: August 2010

AbstractSerotiny—the retention of seeds in the mother plant for over a year—in unpredictable environments may increase the probability that at least some seeds are dispersed during favorable periods. Propagules may be expelled when environmental cues announcing favorable conditions occur, or be gradually released into the environment. This could be a bet‐hedging strategy increasing the long‐term fitness by reducing interannual variability in reproduction. However, the impact of seed retention on the population dynamics of serotinous species and its contribution to fitness has been barely explored under field conditions. We assessed these issues in the threatened Mammillaria pectinifera, a small globose cactus that gets established only in exceptionally rainy years. This species expels some seeds actively during unusually rainy periods, while dispersing others passively over several years. Dynamics of the seeds in the mother plant over two very contrasting years in terms of precipitation was incorporated into a stochastic matrix model. Seed retention was found to increase significantly the probability that some of the seeds retained in any given year are dispersed within a subsequent rainy period. Active seed‐expulsion raises this probability even further. As expected in bet hedgers, seed retention increased fitness in the presence of temporal variability. Active fruit expulsion did not affect fitness, but reduced demographic stochasticity. The incomplete serotiny and fruit expulsion observed is the evolutionary outcome expected for the environment and life‐history attributes of the species.
Compromized geranylgeranylation of RhoA and Rac1 in mevalonate kinase deficiency
Authors: Henneman L. , Schneiders M. S. , Turkenburg M. , Waterham H. R. 
Published: September 2010

AbstractMevalonate kinase deficiency (MKD) is an autoinflammatory disorder caused by mutations in the MVK gene resulting in decreased activity of the enzyme mevalonate kinase (MK). Although MK is required for biosynthesis of all isoprenoids, in MKD, in particular, the timely synthesis of geranylgeranyl pyrophosphate appears to be compromised. Because small guanosine triphosphatases (GTPases) depend on geranylgeranylation for their proper signaling function, we studied the effect of MK deficiency on geranylgeranylation and activation of the two small GTPases, RhoA and Rac1. We demonstrate that both geranylgeranylation and activation of the two GTPases are more easily disturbed in MKD cells than in control cells when the flux though the isoprenoid biosynthesis pathway is suppressed by low concentrations of simvastatin. The limited capacity of geranylgeranylation in MKD cells readily leads to markedly increased levels of nonisoprenylated and activated GTPases, which will affect proper signaling by these GTPases.
Progression of functional limitations in relation to physical activity: a life course approach
Authors: von Bonsdorff Mikaela B. , Rantanen Taina 
Published: August 2010

Abstract
In this minireview, we summarize the research results to date on the progression of functional limitations and the role of physical activity during the life course in preventing risk factor accumulation. In addition, socioeconomic and health disparities play a role in the development process of functional limitation throughout life. We discuss the potential role of physical activity in alleviating this process. Functional limitations usually develop gradually over an extended period of time while the level of physical functioning varies greatly already from midlife onwards. Current research strongly suggests that physical activity has a beneficial effect on functional limitations at different life stages on the population level. However, the potential impact of physical activity in alleviating the effects caused by socioeconomic disparities is inconsistent. Research findings are also conflicting on the extent of the effect of physical activity among certain subsets of the population, such as obese persons. Although the benefits of physical activity on physical impairments and functioning among the adult population have been confirmed, the number of adults who are physically active is too low and, for the majority, physical activity declines with older age. Thus, detailed research evidence is needed for designing effective preventive interventions starting from earlier ages and continuing throughout the lifespan across different subgroups in the population.