bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homogentisate Phytyltransferase Activity Is Limiting for Tocopherol Biosynthesis in Arabidopsis
Authors: Collakova Eva , DellaPenna Dean 
Published: February 2003

AbstractTocopherols are essential components of the human diet and are synthesized exclusively by photosynthetic organisms. These lipophilic antioxidants consist of a chromanol ring and a 15-carbon tail derived from homogentisate (HGA) and phytyl diphosphate, respectively. Condensation of HGA and phytyl diphosphate, the committed step in tocopherol biosynthesis, is catalyzed by HGA phytyltransferase (HPT). To investigate whether HPT activity is limiting for tocopherol synthesis in plants, the gene encoding Arabidopsis HPT,HPT1, was constitutively overexpressed in Arabidopsis. In leaves, HPT1 overexpression resulted in a 10-fold increase in HPT specific activity and a 4.4-fold increase in total tocopherol content relative to wild type. In seeds, HPT1overexpression resulted in a 4-fold increase in HPT specific activity and a total seed tocopherol content that was 40% higher than wild type, primarily because of an increase in γ-tocopherol content. This enlarged pool of γ-tocopherol was almost entirely converted to α-tocopherol by crossing HPT1 overexpressing plants with lines constitutively overexpressing γ-tocopherol methyltransferase. Seed of the resulting double overexpressing lines had a 12-fold increase in vitamin E activity relative to wild type. These results indicate that HPT activity is limiting in various Arabidopsis tissues and that total tocopherol levels and vitamin E activity can be elevated in leaves and seeds by combined overexpression of the HPT1 and γ-tocopherol methyltransferase genes.
Osmotic Stress Tolerance of Transgenic Tobacco Expressing a Gene Encoding a Membrane-Located Receptor-Like Protein from Tobacco Plants
Authors: Tamura Takashi , Hara Kojiro , Yamaguchi Yube , Koizumi Nozomu , Sano Hiroshi 
Published: February 2003

Abstract
Tobacco (Nicotiana tabacum) genes regulated during the early stage of responses to wounding were screened by a modified fluorescence differential display method. Among 28 genes initially identified, a particular clone designatedNtC7 was subjected to further analysis. Its transcripts were found to accumulate rapidly and transiently within 1 h upon treatments with not only wounding but also salt and osmotic stresses. However, jasmonic and abscisic acids and ethylene did not effectively induce NtC7 transcripts. Amino acid sequence analysis suggested NtC7 to be a new type of transmembrane protein that belongs to the receptor-like protein family, and a membrane location was confirmed in onion (Allium cepa) epidermis cells transiently expressing an NtC7-green fluorescent protein fusion protein. Seeds of transgenic tobacco overexpressing NtC7normally germinated and grew in the presence of 500 mmmannitol, but not in the presence of 220 mm sodium chloride or 60 mm lithium chloride. Cuttings of mature transgenic leaf exhibited a marked tolerance upon treatment with 500 mm mannitol for 12 h, at which concentration wild-type counterparts were seriously damaged. These results suggested that NtC7 predominantly functions in maintenance of osmotic adjustment independently of ion homeostasis.
Minidose Warfarin Prophylaxis for Catheter-Associated Thrombosis in Cancer Patients: Can It Be Safely Associated With Fluorouracil-Based Chemotherapy?
Authors: Masci Giovanna , Magagnoli Massimo , Zucali Paolo Andrea , Castagna Luca , Carnaghi Carlo , Sarina Barbara , Pedicini Vittorio , Fallini Monica , Santoro Armando 
Published: February 2003

Purpose: The use of prophylactic low-dose oral warfarin in cancer patients with a central venous catheter (CVC) in place has an established role in the prevention of thrombotic complications and is associated with a low hemorrhagic risk. Despite the literature indicating an adverse interaction between warfarin and fluorouracil (FU), the frequency of this interaction and whether it occurs when minidose warfarin is used is unknown. We analyzed the incidence of alterations in the International Normalized Ratio (INR) and bleeding in cancer patients given minidose warfarin during treatment with continuous-infusion FU-based regimens.Patients and Methods: Between July 1999 and August 2001, 95 cancer patients were evaluated. Forty-one patients (43%) had liver metastases. Seventy-nine patients (83%) had a Groshong CVC (Bard Access System, Salt Lake City, UT), and 16 (17%) had a Port-a-Cath device (Bard Access System). All patients received oral warfarin at a dose of 1 mg/daily as prophylaxis beginning the day after the catheter was positioned. An INR of more than 1.5 was considered significantly elevated.Results: INR elevation occurred in 31 patients (33%), with 18 patients (19%) having an INR more than 3.0. Twelve (39%) of the 31 patients had liver metastases. Bleeding was observed in eight patients (8%); seven of these patients had elevated INR levels. We observed INR elevations in 12 of 21 patients treated with a FU, folinic acid, and oxaliplatin (FOLFOX) regimen, 11 of 40 treated with a de Gramont regimen (FU and folinic acid), and five of 19 treated with a FU, folinic acid, and irinotecan (FOLFIRI) regimen.Conclusion: A high incidence of INR abnormalities was observed in our cohort of patients, especially those treated with FOLFOX regimen. Clinicians should be aware of this interaction and should regularly monitor the prothrombin time in patients receiving warfarin and FU.
Interleukin-2 After Autologous Stem-Cell Transplantation for Adult Patients With Acute Myeloid Leukemia in First Complete Remission
Authors: Stein Anthony S. , O’Donnell Margaret R. , Slovak Marilyn L. , Snyder David S. , Nademanee Auayporn P. , Parker Pablo , Molina Arturo , Somlo George , Fung Henry C. , Krishnan Amrita , Rodriguez Roberto , Spielberger Ricardo T. , Wang Shirong , Dagis Andrew , Vora Nayana , Arber Daniel A. , Niland Joyce C. , Forman Stephen J. 
Published: February 2003

Purpose: To determine the disease-free survival (DFS) and toxicity of administering interleukin-2 (IL-2) immunotherapy early after autologous stem-cell transplantation (ASCT) to simulate a graft versus leukemia effect observed in allogeneic transplantation. Patients and Methods: Fifty-six patients with acute myeloid leukemia in first remission received a single consolidation of high-dose cytarabine-idarubicin at a median of 1.1 month postremission with the intent to proceed to ASCT and IL-2 9 × 106 U/m2/24 h for 4 days, followed by 10 days of IL-2 1.6 × 106 U/m2/24 h on hematologic recovery. Results: Eighty-four percent of patients received the intended ASCT, and 68% of patients received IL-2 treatment. With a median follow-up of 39.4 months (range, 1.2 to 76.3 months), the 2-year cumulative probability of DFS for all 56 patients is 68% (95% confidence interval [CI], 55% to 80%) and 74% (95% CI, 57% to 85%) for the 39 patients undergoing IL-2 treatment after ASCT. The 2-year cumulative probability of DFS for favorable, intermediate, and unfavorable cytogenetics is 88% (95% CI, 59% to 97%), 48% (95% CI, 26% to 67%), and 70% (95% CI, 23% to 93%), respectively. Toxicities from IL-2 were mainly thrombocytopenia, leukopenia, fever, and fluid retention. Two septic deaths occurred during neutropenia, which includes one during consolidation and one during transplant, for an overall 4% mortality rate. Conclusion: These results suggest that a moderate dose of IL-2 after high-dose cytarabine-idarubicin–mobilized ASCT is associated with a low regimen-related toxicity and may improve DFS. A phase III study of IL-2 is now warranted.
Divergent Expression of Type 2 Deiodinase and the Putative Thyroxine-Binding Protein p29, in Rat Brain, Suggests that They Are Functionally Unrelated Proteins
Authors: Montero-Pedrazuela Ana , Bernal Juan , Guadaño-Ferraz Ana 
Published: February 2003

Deiodinases (D1, D2, and D3) are selenoproteins involved in thyroid hormone metabolism. Generation of the active hormone T3, from T4, is carried out by D1 and D2, whereas D3 degrades both hormones. The identity of the cloned D2 as a selenoprotein is well supported by biochemical and physiological data. However, an alternative view has proposed that type 2 deiodinase is a nonselenoprotein complex containing a putative T4 binding subunit called p29, with an almost identity in sequence with the Dickkopf protein Dkk3.To explore a possible functional relationship between p29 and D2, we have compared their mRNA expression patterns in the rat brain. In brain, parenchyma p29 was expressed in neurons. High expression levels were found in all the regions of the blood-cerebrospinal fluid (CSF) barrier. p29 was present in different types of cells than D2, with the exception of the tanycytes. Our data do not support that p29 has a functional relationship with D2. On the other hand, expression of p29 in the blood-CSF barrier suggests that it might be involved in T4 transport to and from the CSF, but further studies are needed to substantiate this hypothesis.
Enhanced Effect of Mesoporous Silica on Base-Catalyzed Aldol Reaction
Authors: Kubota Yoshihiro , Goto Kunio , Miyata Shintaro , Goto Yasutomo , Fukushima Yoshiaki , Sugi Yoshihiro 
Published: February 2003

Abstract
Aldol reaction of 4-nitrobenzaldehyde with acetone gives 4-(4-nitrophenyl)-4-hydroxy-2-butanone in high yield in the presence of both secondary amine and mesoporous silica, whereas the yield is low in the absence of the mesoporous silica.
Periodic Expansion-contraction Motion of Photoabsorbing Organic Droplets during Laser Photophoretic Migration in Water
Authors: Monjushiro Hideaki , Tanaka Makiko , Watarai Hitoshi 
Published: February 2003

Abstract
Laser photophoretic behavior of 2-benzylpyridine droplets including Co(III)-pyridylazo complex as a photoabsorber was examined in water by irradiating cw Ar+ ion laser. We have made a new observation like a “breathing” motion that the droplets repeated the expansion and the sudden contraction during laser photophoretic migration. The period of the motion decreased with increasing the Co complex concentration in the droplet and also with increasing the laser power. The origin of the motion is the water vaporization in the droplet by photothermal conversion.
Study on Thermal-addressing Characteristics of (Polymer Network/Liquid Crystals/Chiral Dopant) Composite
Authors: Yang Huai , Kikuchi Hirotsugu , Kajiyama Tisato 
Published: February 2003

Abstract
A [polymer network/liquid crystals (LCs)/chiral dopant] composite with a smectic A (Sa) ↔ chiral nematic (N*) phase transition is prepared. A very drastic change from the light-scattering Sa phase to the transparent N* one is achieved upon heating the composite. The transparent state of the N* phase is ‘frozen’ in the Sa phase upon cooling. When an ac electric field is applied to the composite, the transparent Sa phase is changed into the light-scattering Sa one again.
Potassium Triiodide. A New and Efficient Catalyst for Carbon–Carbon Bond Formation in Aqueous Media
Authors: Thakur Ashim J , Prajapati Dipak , Gogoi Baikuntha J , Sandhu Jagir S 
Published: February 2003

Abstract
Potassium triiodide catalyses the condensation of carbonyl compounds with active methylene compounds in aqueous media to afford E olefinic products in high yields.
Vapochromic Properties of Nafion Film Doped with Cationic Dyes
Authors: Matsushima Ryoka , Nishimura Naoko , Kohno Yoshiumi 
Published: February 2003

Abstract
Protonated Nafion thin film doped with cationic dyes such as flavylium and thionine revealed rapid and vapor-specific color changes (vapochromism) upon exposure to volatile organic compounds. The vapochromic performances were substantially retained after 10 repeated cycles of exposures, implying good reversibility.
Swimming behaviour of the unicellular biflagellate Oxyrrhis marina: in vivo and in vitro movement of the two flagella
Authors: Cosson Jacky , Cachon Monique , Cachon Jean , Cosson Marie‐Paule 
Published: February 2003

Summary— The movement of the 2 flagella of Oxyrrhis marina was examined with respect to their individual waveforms and the swimming behaviour of the organism. The longitudinal flagella propagated helicoidal waves whose amplitude decreased toward the tip of the flagellum. Their beat frequencies were 50–60 Hz. The transverse flagella beat helicoidally within a furrow. Sudden changes in the direction of the cell trajectories were generated by transient arrests of the longitudinal flagellum beat, which were accompanied by a switch from the backward orientation to a forward one. This sweeping motion generated the rotation of the cell body. Ca2+ ions highly stimulated the frequencies of this arrest response, which compared to the “walking‐stick” behaviour of sea urchin spermatozoa.Isolated flagella were ATP‐reactivated after detergent treatment. They exhibited 2 types of motion within the same experimental conditions. A progressive helicoidal motion was generated upon longitudinal flagellum reactivation, whereas a rolling motion with little progression characterized transverse flagellum reactivation. The differences motile behaviour reflect regulations of flagellar movement which were not destroyed by the isolation procedure and may be indicative of regulation of accessory structures.
From cilia and flagella to intracellular motility and back again: a review of a few aspects of microtubule‐based motility
Authors: Huitorel Philippe 
Published: February 2003

Summary— Ciliary or flagellar movement is the model of microtubule‐dependent motility, the best studied at the molecular level. It is based on the relative sliding of outer doublets of microtubules that are linked at their proximal end to the basal structure and interconnected by associated proteins, among which dynein ATPase is at the origin of the movement. It is regulated from inside and outside media by various diffusible factors such as Ca2+, cyclic adenosine monophosphate (cAMP), polypeptides and so on (see other conferences presented during this meeting).Other motility processes are based on microtubules: vesicle and organelle transport through the cytoplasm (axonal flow in neurons, pigment granule movements in fish chromatophores, movements of particles along heliozoan axopods, etc.) could be mediated by microtubule motors such as kinesin or MAP 1C. Kinesin and MAP 1C, like dynein, are proteins that bind to microtubules and show an ATPase activity associated with force production. They differ from each other by their structure, and biochemical and pharmacological properties.The movements of chromosomes during mitosis and melosis have long been studied, but are still poorly understood at the molecular level; this topic will be discussed in the light of recent data.Other constituents of the cytoskeleton are certainly involved in cellular motility: actin microfilaments and their motor myosin, intermediate filaments, non‐actin filaments, all organized around te Microtubule Organizing Center (MTOC). As more information becomes available, it seems increasingly obvious that these various networks are closely interconnected and that each component probably modulates, resists, or favors properties of its partners, contributing to cellular and intracellular motility.
Bias in species range estimates from minimum convex polygons: implications for conservation and options for improved planning
Authors: Burgman Mark A. , Fox Julian C. 
Published: February 2003

AbstractMinimum convex polygons (convex hulls) are an internationally accepted, standard method for estimating species' ranges, particularly in circumstances in which presence‐only data are the only kind of spatially explicit data available. One of their main strengths is their simplicity. They are used to make area statements and to assess trends in occupied habitat, and are an important part of the assessment of the conservation status of species. We show by simulation that these estimates are biased. The bias increases with sample size, and is affected by the underlying shape of the species habitat, the magnitude of errors in locations, and the spatial and temporal distribution of sampling effort. The errors affect both area statements and estimates of trends. Some of these errors may be reduced through the application of α‐hulls, which are generalizations of convex hulls, but they cannot be eliminated entirely. α‐hulls provide an explicit means for excluding discontinuities within a species range. Strengths and weaknesses of alternatives including kernel estimators were examined. Convex hulls exhibit larger bias than α‐hulls when used to quantify habitat extent and to detect changes in range, and when subject to differences in the spatial and temporal distribution of sampling effort and spatial accuracy. α‐hulls should be preferred for estimating the extent of and trends in species' ranges.
Sequence Analysis of a 282-Kilobase Region Surrounding the Citrus Tristeza Virus Resistance Gene (Ctv) Locus inPoncirus trifoliata L. Raf.
Authors: Yang Zhong-Nan , Ye Xin-Rong , Molina Joe , Roose Mikeal L. , Mirkov T. Erik 
Published: February 2003

Abstract
Citrus tristeza virus (CTV) is the major virus pathogen causing significant economic damage to citrus worldwide, and a single dominant gene, Ctv, provides broad spectrum resistance to CTV inPoncirus trifoliata L. Raf. Ctv was physically mapped to a 282-kb region using a P. trifoliata bacterial artificial chromosome library. This region was completely sequenced to about 8× coverage using a shotgun sequencing strategy and primer walking for gap closure. Sequence analysis predicts 22 putative genes, two mutator-like transposons and eight retrotransposons. This sequence analysis also revealed some interesting features of this region of the P. trifoliata genome: a disease resistance gene cluster with seven members and eight retrotransposons clustered in a 125-kb gene-poor region. Comparative sequence analysis suggests that six genes in theCtv region have significant sequence similarity with their orthologs in bacterial artificial chromosome clones F7H2 and F21T11 from Arabidopsis chromosome I. However, the analysis of gene colinearity between P. trifoliata and Arabidopsis indicates that Arabidopsis genome sequence information may be of limited use for positional gene cloning in P. trifoliataand citrus. Analysis of candidate genes for Ctv is also discussed.
Xylem Ray Parenchyma Cells in Boreal Hardwood Species Respond to Subfreezing Temperatures by Deep Supercooling That Is Accompanied by Incomplete Desiccation
Authors: Kuroda Katsushi , Kasuga Jun , Arakawa Keita , Fujikawa Seizo 
Published: February 2003

AbstractIt has been accepted that xylem ray parenchyma cells (XRPCs) in hardwood species respond to subfreezing temperatures either by deep supercooling or by extracellular freezing. Present study by cryo-scanning electron microscopy examined the freezing responses of XRPCs in five boreal hardwoods: Salix sachalinensis Fr. Schmit, Populus sieboldii Miq., Betula platyphylla Sukat. var japonica Hara,Betula pubescens Ehrh., and red osier dogwood (Cornus sericea), in which XRPCs have been reported to respond by extracellular freezing. Cryo-scanning electron microscopy observations revealed that slow cooling of xylem to −80°C resulted in intracellular freezing in the majority of XRPCs in S. sachalinensis, an indication that these XRPCs had been deep supercooled. In contrast, in the majority of XRPCs in P. sieboldii, B. platyphylla, B. pubescens, and red osier dogwood, slow cooling to −80°C produced slight cytorrhysis without clear evidence of intracellular freezing, suggesting that these XRPCs might respond by extracellular freezing. In these XRPCs exhibited putative extracellular freezing; however, deep etching revealed the apparent formation of intracellular ice crystals in restricted local areas. To confirm the occurrence of intracellular freezing, we rewarmed these XRPCs after cooling and observed very large intracellular ice crystals as a result of the recrystallization. Thus, the XRPCs in all the boreal hardwoods that we examined responded by deep supercooling that was accompanied with incomplete desiccation. From these results, it seems possible that limitations to the deep-supercooling ability of XRPCs might be a limiting factor for adaptation of hardwoods to cold climates.
Differences in Whole-Cell and Single-Channel Ion Currents across the Plasma Membrane of Mesophyll Cells from Two Closely RelatedThlaspi Species
Authors: Piñeros Miguel A. , Kochian Leon V. 
Published: February 2003

Abstract
The patch clamp technique was used to study the physiology of ion transport in mesophyll cells from two Thlaspispp. that differ significantly in their physiology. In comparison withThlaspi arvense, Thlaspi caerulescens (a heavy metal accumulator) can grow in, tolerate, and accumulate very high levels of certain heavy metals (primarily zinc [Zn] and cadmium) in their leaf cells. The membrane conductance of every T. arvense leaf cell was dominated by a slowly activating, time-dependent outward rectifying current (SKOR). In contrast, only 23% of T. caerulescens cells showed SKOR activity, whereas the remaining 77% exhibit a rapidly developing instantaneous K+ outward rectifier (RKOR) current. In contrast to RKOR, the channels underlying the SKOR current were sensitive to changes in the extracellular ion activity. Single-channel recordings indicated the existence of K+ channel populations with similar unitary conductances, but distinct channel kinetics and regulation. The correlation between these recordings and the whole-cell data indicated that although one type of channel kinetics is preferentially activated in each Thlaspi spp., both species have the capability to switch between either type of current. Ion substitution in whole-cell and single-channel experiments indicated that although the SKOR and RKOR channels mediate a net outward K+ current, they can also allow a significant Zn2+ permeation (i.e. influx). In addition, single-channel recordings allowed us to identify an infrequent type of plasma membrane divalent cation channel that also can mediate Zn2+ influx. We propose that the different K+ channel types or channel states may result from and are likely to reflect differences in the cytoplasmic and apoplastic ionic environment in each species. Thus, the ability to interchangeably switch between different channel states allows each species to constantly adjust to changes in their apoplastic ionic environment.
Characterization of a Plant Homolog of Hop, a Cochaperone of Hsp90
Authors: Zhang Zhongming , Quick Michelle K. , Kanelakis Kimon C. , Gijzen Mark , Krishna Priti 
Published: February 2003

Abstract
The 90-kD molecular chaperone hsp90 is the key component of a multiprotein chaperone complex that facilitates folding, stabilization, and functional modulation of a number of signaling proteins. The components of the animal chaperone complex include hsp90, hsp70, hsp40, Hop, and p23. The animal Hop functions to link hsp90 and hsp70, and it can also inhibit the ATPase activity of hsp90. We have demonstrated the presence of an hsp90 chaperone complex in plant cells, but not all components of the complex have been identified. Here, we report the isolation and characterization of soybean (Glycine max) GmHop-1, a soybean homolog of mammalian Hop. An analysis of soybean expressed sequence tags, combined with preexisting data in literature, suggested the presence of at least three related genes encoding Hop-like proteins in soybean. Transcripts corresponding to Hop-like proteins in soybean were detected under normal growth conditions, and their levels increased further in response to stress. A recombinant GmHop-1 bound hsp90 and its binding to hsp90 could be blocked by the tetratricopeptide repeat (TPR) domain of rat (Rattus norvegicus) protein phosphatase 5. Deletion of amino acids 325 to 395, adjacent to the TPR2A domain in GmHop-1, resulted in loss of hsp90 binding. In a minimal assembly system, GmHop-1 was able to stimulate mammalian steroid receptor folding. These data show that plant and animal Hop homologs are conserved in their general characteristics, and suggest that a Hop-like protein in plants is an important cochaperone of plant hsp90.