bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immobilization of Aluminum with Phosphorus in Roots Is Associated with High Aluminum Resistance in Buckwheat
Authors: Zheng Shao Jian , Yang Jian Li , He Yun Feng , Yu Xue Hui , Zhang Lei , You Jiang Feng , Shen Ren Fang , Matsumoto Hideaki 
Published: April 2005

Abstract
Oxalic acid secretion from roots is considered to be an important mechanism for aluminum (Al) resistance in buckwheat (Fygopyrum esculentum Moench). Nonetheless, only a single Al-resistant buckwheat cultivar was used to investigate the significance of oxalic acid in detoxifying Al. In this study, we investigated two buckwheat cultivars, Jiangxi (Al resistant) and Shanxi (Al sensitive), which showed significant variation in their resistance to Al stress. In the presence of 0 to 100 μ m Al, the inhibition of root elongation was greater in Shanxi than that in Jiangxi, and the Al content of root apices (0–10 mm) was much lower in Jiangxi. However, the dependence of oxalic acid secretion on external Al concentration and the time course for secretion were similar in both cultivars. Furthermore, the variation in Al-induced oxalic acid efflux along the root was similar, showing a 10-fold greater efflux from the apical 0- to 5-mm region than from the 5- to 10-mm region. These results suggest that both Shanxi and Jiangxi possess an equal capacity for Al-dependent oxalic acid secretion. Another two potential Al resistance mechanisms, i.e. Al-induced alkalinization of rhizosphere pH and root inorganic phosphate release, were also not involved in their differential Al resistance. However, after longer treatments in Al (10 d), the concentrations of phosphorus and Al in the roots of the Al-resistant cultivar Jiangxi were significantly higher than those in Shanxi. Furthermore, more Al was localized in the cell walls of the resistant cultivar. All these results suggest that while Al-dependent oxalic acid secretion might contribute to the overall high resistance to Al stress of buckwheat, this response cannot explain the variation in tolerance between these two cultivars. We present evidence suggesting the greater Al resistance in buckwheat is further related to the immobilization and detoxification of Al by phosphorus in the root tissues.
Destination-Selective Long-Distance Movement of Phloem Proteins
Authors: Aoki Koh , Suzui Nobuo , Fujimaki Shu , Dohmae Naoshi , Yonekura-Sakakibara Keiko , Fujiwara Toru , Hayashi Hiroaki , Yamaya Tomoyuki , Sakakibara Hitoshi 
Published: April 2005

AbstractThe phloem macromolecular transport system plays a pivotal role in plant growth and development. However, little information is available regarding whether the long-distance trafficking of macromolecules is a controlled process or passive movement. Here, we demonstrate the destination-selective long-distance trafficking of phloem proteins. Direct introduction, into rice (Oryza sativa), of phloem proteins from pumpkin (Cucurbita maxima) was used to screen for the capacity of specific proteins to move long distance in rice sieve tubes. In our system, shoot-ward translocation appeared to be passively carried by bulk flow. By contrast, root-ward movement of the phloem RNA binding proteins 16-kD C. maxima phloem protein 1 (CmPP16-1) and CmPP16-2 was selectively controlled. When CmPP16 proteins were purified, the root-ward movement of CmPP16-1 became inefficient, suggesting the presence of pumpkin phloem factors that are responsible for determining protein destination. Gel-filtration chromatography and immunoprecipitation showed that CmPP16-1 formed a complex with other phloem sap proteins. These interacting proteins positively regulated the root-ward movement of CmPP16-1. The same proteins interacted with CmPP16-2 as well and did not positively regulate its root-ward movement. Our data demonstrate that, in addition to passive bulk flow transport, a destination-selective process is involved in long-distance movement control, and the selective movement is regulated by protein–protein interaction in the phloem sap.
A Tiling Microarray Expression Analysis of Rice Chromosome 4 Suggests a Chromosome-Level Regulation of Transcription
Authors: Jiao Yuling , Jia Peixin , Wang Xiangfeng , Su Ning , Yu Shuliang , Zhang Dongfen , Ma Ligeng , Feng Qi , Jin Zhaoqing , Li Lei , Xue Yongbiao , Cheng Zhukuan , Zhao Hongyu , Han Bin , Deng Xing Wang 
Published: April 2005

AbstractThe complete genome sequence of cultivated rice (Oryza sativa) provides an unprecedented opportunity to understand the biology of this model cereal. An essential and necessary step in this effort is the determination of the coding information and expression patterns of each sequenced chromosome. Here, we report an analysis of the transcriptional activity of rice chromosome 4 using a tiling path microarray based on PCR-generated genomic DNA fragments. Six representative rice organ types were examined using this microarray to catalog the transcribed regions of rice chromosome 4 and to reveal organ- and developmental stage–specific transcription patterns. This analysis provided expression support for 82% of the gene models in the chromosome. Transcriptional activities in 1643 nonannotated regions were also detected. Comparison with cytologically defined chromatin features indicated that in juvenile-stage rice the euchromatic region is more actively transcribed than is the transposon-rich heterochromatic portion of the chromosome. Interestingly, increased transcription of transposon-related gene models in certain heterochromatic regions was observed in mature-stage rice organs and in suspension-cultured cells. These results suggest a close correlation between transcriptional activity and chromosome organization and the developmental regulation of transcription activity at the chromosome level.
Microtubule Dynamics in Living Root Hairs: Transient Slowing by Lipochitin Oligosaccharide Nodulation Signals
Authors: Vassileva Valya N. , Kouchi Hiroshi , Ridge Robert W. 
Published: April 2005

AbstractThe incorporation of a fusion of green fluorescent protein and tubulin-α 6 from Arabidopsis thaliana in root hairs of Lotus japonicus has allowed us to visualize and quantify the dynamic parameters of the cortical microtubules in living root hairs. Analysis of individual microtubule turnover in real time showed that only plus polymer ends contributed to overall microtubule dynamicity, exhibiting dynamic instability as the main type of microtubule behavior in Lotus root hairs. Comparison of the four standard parameters of in vivo dynamic instability—the growth rate, the disassembly rate, and the frequency of transitions from disassembly to growth (rescue) and from growth to disassembly (catastrophe)—revealed that microtubules in young root hairs were more dynamic than those in mature root hairs. Either inoculation with Mesorhizobium loti or purified M. loti lipochitin oligosaccharide signal molecules (Nod factors) significantly affected the growth rate and transition frequencies in emerging and growing root hairs, making microtubules less dynamic at a specific window after symbiotic inoculation. This response of root hair cells to rhizobial Nod factors is discussed in terms of the possible biological significance of microtubule dynamics in the early signaling events leading to the establishment and progression of the globally important Rhizobium/legume symbiosis.
KATAMARI1/MURUS3 Is a Novel Golgi Membrane Protein That Is Required for Endomembrane Organization in Arabidopsis
Authors: Tamura Kentaro , Shimada Tomoo , Kondo Maki , Nishimura Mikio , Hara-Nishimura Ikuko 
Published: April 2005

Abstract
In plant cells, unlike animal and yeast cells, endomembrane dynamics appear to depend more on actin filaments than on microtubules. However, the molecular mechanisms of endomembrane–actin filament interactions are unknown. In this study, we isolated and characterized an Arabidopsis thaliana mutant, katamari1 (kam1), which has a defect in the organization of endomembranes and actin filaments. The kam1 plants form abnormally large aggregates that consist of endoplasmic reticulum with actin filaments in the perinuclear region within the cells and are defective in normal cell elongation. Map-based cloning revealed that the KAM1 gene is allelic to the MUR3 gene. We demonstrate that the KAM1/MUR3 protein is a type II membrane protein composed of a short cytosolic N-terminal domain and a transmembrane domain followed by a large lumenal domain and is localized specifically on Golgi membranes. We further show that actin filaments interact with Golgi stacks via KAM1/MUR3 to maintain the proper organization of endomembranes. Our results provide functional evidence that KAM1/MUR3 is a novel component of the Golgi-mediated organization of actin functioning in proper endomembrane organization and cell elongation.
Key Factors of Joint‐Liability Loan Contracts: An Empirical Analysis
Authors: Kritikos Alexander S. , Vigenina Denitsa 
Published: April 2005

SummaryThis paper provides an empirical analysis of joint‐liability micro‐lending contracts. Using our data set, we examine the efficacy of various incentives set by this contract such as joint‐liability between groups of borrowers or group access to future and to larger loans. As proposed by theory, we find that joint liability induces a group formation of low risk borrowers. After the loan disbursement, the incentive system leads to peer monitoring, peer support and peer pressure between the borrowers, thus helping the lending institution to address the moral hazard and enforcement problem. This paper also demonstrates that the mechanism realizes repayment rates of nearly 100% if the loan officers fulfill their complementary duties in the screening and enforcement process. Finally, we make clear that dynamic incentives, in contrast to theory, have to be restricted if the two long‐term problems of the joint‐liability approach, i.e. its mismatching problem and the domino effect, are to be tackled notably.
Event-Related Potential Correlates of Long-Term Memory for Briefly Presented Faces
Authors: Joyce Carrie A. , Kutas Marta 
Published: April 2005

Abstract
Electrophysiological studies have investigated the nature of face recognition in a variety of paradigms; some have contrasted famous and novel faces in explicit memory paradigms, others have repeated faces to examine implicit memory/ priming. If the general finding that implicit memory can last for up to several months also holds for novel faces, a reliable measure of it could have practical application for eyewitness testimony, given that explicit measures of eyewitness memory have at times proven fallible. The current study aimed to determine whether indirect behavioral and electrophysiological measures might yield reliable estimates of face memory over longer intervals than have typically been obtained with priming manipulations. Participants were shown 192 faces and then tested for recognition at four test delays ranging from immediately up to 1 week later. Three event-related brain potential components (e.g., N250r, N400f, and LPC) varied with memory measures although only the N250r varied regardless of explicit recognition, that is, with both repetition and recognition.
Ectopic and IFN-induced expression of Fas overcomes resistance to Fas-mediated apoptosis in multiple myeloma cells
Authors: Dimberg Lina Y. , Dimberg Anna I. , Ivarsson Karolina , Strömberg Thomas , Österborg Anders , Nilsson Kenneth , Öberg Fredrik , Wiklund Helena Jernberg 
Published: April 2005

AbstractMultiple myeloma (MM) is an as-yet incurable B-cell malignancy. Increased survival in vitro is a hallmark of MM cells, implying that a therapeutic potential may lie in circumventing antiapoptotic signals. We have previously reported that interferons (IFNs) sensitize MM cells to Fas/CD95-mediated apoptosis. In the present study, we explore the mechanism underlying this effect. In a wide screening of apoptosis-related genes, Apo2L/TRAIL (tumor necrosis factor [TNF]-related apoptosis inducing ligand) and Fas were identified as IFN targets. Sensitization to Fas-mediated apoptosis by IFNs was not affected by blocking Apo2L/TRAIL, suggesting that Apo2L/TRAIL is not a key mediator in this process. In contrast, we found that an elevated Fas expression was functionally linked to increased susceptibility to Fas-mediated apoptosis. This was further supported by the finding that IFN treatment enhanced Fas-mediated caspase-8 activation, one of the earliest signaling events downstream receptor activation. In addition, IFN treatment attenuated the interleukin 6 (IL-6)-dependent activation of signal transducer and activator of transcription 3 (Stat3), interfering with a known survival pathway in MM that has previously been linked with resistance to Fas-mediated apoptosis. Taken together, our results show that IFN-induced up-regulation of Fas sensitizes MM cells to Fas-mediated apoptosis and suggest that attenuation of Stat3 activation may be a potentially important event in this process. (Blood. 2005;106:1346-1354)
cDNA cloning and heterologous expression of a wheat proteinase inhibitor of subtilisin and chymotrypsin (WSCI) that interferes with digestive enzymes of insect pests
Authors: Di Gennaro Simone , Ficca Anna G. , Panichi Daniela , Poerio Elia 
Published: April 2005

AbstractA cDNA encoding the proteinase inhibitor WSCI (wheat subtilisin/chymotrypsin inhibitor) was isolated by RT-PCR. Degenerate oligonucleotide primers were designed based on the amino acid sequence of WSCI and on the nucleotide sequence of the two homologous inhibitors (CI-2A and CI-2B) isolated from barley. For large-scale production,wscicDNA was cloned into theE. colivector pGEX-2T. The fusion protein GST-WSCI was efficiently produced in the bacterial expression system and, as the native inhibitor, was capable of inhibiting bacterial subtilisin, mammalian chymotrypsins and chymotrypsin-like activities present in crude extracts of a number of insect larvae (Helicoverpa armigera,Plodia interpunctellaandTenebrio molitor). The recombinant protein produced was also able to interfere with chymotrypsin-like activity isolated from immature wheat caryopses. These findings support a physiological role for this inhibitor during grain maturation.
Computational Study of Structures and Properties of Metallaboranes: Cobalt Bis(dicarbollide)
Authors: Bühl Michael , Hnyk Drahomír , Macháček Jan 
Published: April 2005

AbstractA density functional study at the BP86/AE1 level is presented for the cobalt bis(dicarbollide) ion [3‐Co‐(1,2‐C2B9H11)2]−(1) and selected isomers and rotamers thereof. Rotation of the two dicarbollide moieties with respect to each other is facile, as judged by the small energetic separation of the three rotamers located (within 11 kJ mol−1) and by the low barriers for their interconversion (at most 41 kJ mol−1). Among the isomers differing in carbon atom positions that contain two equivalent dicarbollide ligands, the 1,7 (“carbon apart”) form [2‐Co‐(1,7‐C2B9H11)2]−is the most stable, 121 kJ mol−1below1. The electronic structure of1is characterized in terms of molecular orbitals, population analysis, and excitation energies from time‐dependent density functional theory, relevant to UV/Vis spectroscopy. Experimental11B NMR chemical shifts of1are reproduced to better than 5 ppm at the GIAO‐B3LYP/II′ level, and the computedδ(11B) values are only little affected by rotational averaging or the presence of a polarizable continuum. Larger such effects are found for the as‐yet unknown59Co chemical shift, for which a value in the range between −1800 and −2400 ppm is predicted. Even though the accuracy achieved for the theoreticalδ(11B) values is somewhat lower than that for heteroboranes at conventional ab initio levels, the level of density functional employed can afford qualitatively reliable chemical shifts, which can be useful in assignments and structural refinements of heteroboranes containing transition metal.
Structural and Binding Features of Cofacial Bis‐Porphyrins with Calixarene Spacers: Pac‐Man Porphyrins That Can Chew
Authors: Jokic Danica , Boudon Corinne , Pognon Grégory , Bonin Michel , Schenk Kurt J. , Gross Maurice , Weiss Jean 
Published: April 2005

AbstractBased on the efficient combination of calixarene spacers and acetylenic porphyrin derivatives, a new generation of cofacial bis‐porphyrins has been synthesized. The first crystal structure of a cofacial bis‐porphyrin–calixarene conjugate is reported. Their unique architectural features, analogous to those of pac‐man‐type bis‐porphyrins, allow these calixarene–porphyrin conjugates to adapt their shape to the size of bidentate guests, such as diazabicyclo[2.2.2]octane (dabco) and 1,4‐pyrazine. The predefined, cofacial arrangement of the porphyrin moieties observed in the solid state and in solution results in extremely high affinities (in the range of 109 M−1) for these guests. The 1,3‐alternate calixarene conformations afford “open‐mouth” pac‐man structures whose ability to bite on nitrogen bidentates depends on their functionalization. A cone conformer provides a much more flexible structure that exhibits the highest affinity for dabco and pyrazine.
The Photochemistry of 4‐Chlorophenol in Water Revisited: The Effect of Cyclodextrins on Cation and Carbene Reactions
Authors: Manet Ilse , Monti Sandra , Bortolus Pietro , Fagnoni Maurizio , Albini Angelo 
Published: April 2005

AbstractThe photochemistry of 4‐chlorophenol (1) in water and in the presence of cyclodextrins has been studied by means of steady‐state and time‐resolved experiments. These have shown that 1 undergoes photoheterolysis of the CCl bond in the triplet state to yield the 4‐hydroxyphenyl cation 32 in equilibrium with 4‐oxocyclohexa‐2,5‐dienylidene, 33. These triplet intermediates scarcely react with a n nucleophile, such as water, nor abstract hydrogen from this solvent, thus they are long‐lived (≈1 μs). Specific trapping of both intermediates has been achieved. The cation adds to 2‐propenol, kadd∼1.3×108 m−1 s−1, to form the long‐lived phenonium ion 11 (with λmax = 290 nm), which then converts to 3‐(4‐hydroxyphenyl)propane‐1,2‐diol (10). Carbene 33 is trapped by oxygen to give benzoquinone and is reduced by D‐glucose (kq = 8.5×106 m−1 s−1) to give the phenoxyl radical (8) and phenol (9). Cyclodextrins have been found to trap the intermediates much more efficiently (kq = 9.4×108 m−1 s−1 with β‐CD), which indicates that inclusion is involved. Ground state 1 forms inclusion complexes with 1:1 stoichiometry and association constants of 140 and 300 M−1 with α‐ and β‐CD, respectively. Complexation does not change the efficiency or the mode of photofragmentation of 1; however, it does influence the course of the reaction because the major portion of the intermediates are reduced to phenol within the cavity (k′red≥5×107 s−1) either via a radical 8 or via a radical cation 9+.. Under these conditions, neither 2‐propenol nor oxygen trap the intermediates to a significant extent.
Pyrazolino[60]fullerene–Oligophenylenevinylene Dumbbell‐Shaped Arrays: Synthesis, Electrochemistry, Photophysics, and Self‐Assembly on Surfaces
Authors: Langa Fernando , Gomez‐Escalonilla Maria J. , Rueff Jean‐Michel , Figueira Duarte Teresa M. , Nierengarten Jean‐François , Palermo Vincenzo , Samorì Paolo , Rio Yannick , Accorsi Gianluca , Armaroli Nicola 
Published: April 2005

AbstractSymmetrically substituted oligophenylenevinylene (OPV) derivatives bearing terminal p‐nitrophenylhydrazone groups have been prepared and used for the synthesis of dumbbell‐shaped bis(pyrazolino[60]fullerene)–OPV systems. In these triad arrays, the OPV‐type fluorescence is dramatically quenched as a consequence of ultrafast OPV→C60 singlet energy transfer. In its turn the fullerene singlet state is quenched by pyrazoline→C60 electron transfer, in line with the behavior of the corresponding reference fullerene molecule. The occurrence of electron transfer in the multicomponent arrays is evidenced by recovery of fullerene fluorescence at 77 K in CH2Cl2 and in toluene at 298 K. Under these conditions the OPV→C60 energy transfer is unaffected. The rate of this process turns out to be higher for the OPV trimer than for the corresponding pentameric OPV arrays, in agreement with energy‐transfer theory expectations. Scanning tunneling microscopy (STM) and scanning force microscopy (SFM) revealed that the bis(pyrazolino[60]fullerene)–OPV can self‐assemble into ordered layered crystalline architectures on the basal plane of highly oriented pyrolitic graphite.
A Guideline to the Design of Molecular‐Based Materials with Long‐Lived Photomagnetic Lifetimes
Authors: Létard Jean‐François , Guionneau Philippe , Nguyen Olivier , Costa José Sánchez , Marcén Silvia , Chastanet Guillaume , Marchivie Mathieu , Goux‐Capes Laurence 
Published: April 2005

AbstractMaterials presenting a stable and reversible switch of physical properties in the solid state are of major interest either for fundamental interests or potential industrial applications. In this context, the design of metal complexes showing a light‐induced crossover from one spin state to another, leading to a major change of magnetic and optical properties, is probably one of the most appealing challenges. The so‐denoted spin‐crossover materials undergo, in some cases, a reversible photoswitch between two magnetic states, but, unfortunately, lifetimes of the photomagnetic states for compounds known so far are long enough only at low temperatures; this prohibits any applications. We have measured and collected the temperatures above which the photomagnetic effect disappears for more than sixty spin‐crossover compounds. On the basis of this large data base, a correlation between the nature of the coordination sphere of the metal and the photomagnetic lifetime can be drawn. Such correlation allows us to propose here a general guideline for the rational design of materials with long‐lived photomagnetic lifetimes. This result clearly opens the way towards room‐temperature photonic materials, based on the spin‐crossover phenomenon, which will be of great interest for future communication devices.
Orientational Isomerism and Binding Ability of Nonsymmetrical Guests Encapsulated in a Self‐Assembling Heterodimeric Capsule
Authors: Kobayashi Kenji , Ishii Kei , Yamanaka Masamichi 
Published: April 2005

AbstractThe ability of a guest to induce the assembly of tetracarboxyl‐cavitand 1 and tetra(3‐pyridyl)‐cavitand 2 into a heterodimeric capsule 1⋅2, and the orientational isomerism of nonsymmetrical p‐disubstituted‐benzene guests encapsulated in 1⋅2, are described. For example, the ability of a guest to induce the assembly of guest⊂(1⋅2) increases in the order p‐iodoaniline≤p‐chloroanisole<p‐bromoanisole<N‐methyl‐p‐iodoaniline<p‐iodoanisole. For these five guests encapsulated in 1⋅2, the halogen atoms are specifically oriented with respect to the cavity of the 2 unit. By contrast, the orientational isomeric selectivities of p‐chloroiodobenzene, p‐bromoiodobenzene, and p‐methylanisole encapsulated in 1⋅2 are quite low, in the range of 1:1.7 to 1:1. The ortho‐fluoro derivatives of these three guests, however, are encapsulated in 1⋅2 with a highly selective orientation, in which the substituent next to the fluorine atom greatly prefers the cavity of the 2 unit to that of the 1 unit.