bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation of a Crystal Matrix Protein Associated with Calcium Oxalate Precipitation in Vacuoles of Specialized Cells
Authors: Li Xingxiang , Zhang Dianzhong , Lynch-Holm Valerie J. , Okita Thomas W. , Franceschi Vincent R. 
Published: October 2003

AbstractThe formation of calcium (Ca) oxalate crystals is considered to be a high-capacity mechanism for regulating Ca in many plants. Ca oxalate precipitation is not a stochastic process, suggesting the involvement of specific biochemical and cellular mechanisms. Microautoradiography of water lettuce (Pistia stratiotes) tissue exposed to 3H-glutamate showed incorporation into developing crystals, indicating potential acidic proteins associated with the crystals. Dissolution of crystals leaves behind a crystal-shaped matrix “ghost” that is capable of precipitation of Ca oxalate in the original crystal morphology. To assess whether this matrix has a protein component, purified crystals were isolated and analyzed for internal protein. Polyacrylamide gel electrophoresis revealed the presence of one major polypeptide of about 55 kD and two minor species of 60 and 63 kD. Amino acid analysis indicates the matrix protein is relatively high in acidic amino acids, a feature consistent with its solubility in formic acid but not at neutral pH. 45Ca-binding assays demonstrated the matrix protein has a strong affinity for Ca. Immunocytochemical localization using antibody raised to the isolated protein showed that the matrix protein is specific to crystal-forming cells. Within the vacuole, the surface and internal structures of two morphologically distinct Ca oxalate crystals, raphide and druse, were labeled by the antimatrix protein serum, as were the surfaces of isolated crystals. These results demonstrate that a specific Ca-binding protein exists as an integral component of Ca oxalate crystals, which holds important implications with respect to regulation of crystal formation.
Development of Protoporphyrinogen Oxidase as an Efficient Selection Marker forAgrobacterium tumefaciens-Mediated Transformation of Maize
Authors: Li Xianggan , Volrath Sandy L. , Nicholl David B.G. , Chilcott Charles E. , Johnson Marie A. , Ward Eric R. , Law Marcus D. 
Published: October 2003

AbstractIn this article, we report the isolation of plant protoporphyrinogen oxidase (PPO) genes and the isolation of herbicide-tolerant mutants. Subsequently, an Arabidopsis double mutant (Y426M + S305L) was used to develop a selectable marker system for Agrobacterium tumefaciens-mediated transformation of maize (Zea mays) and to obtain multiple events tolerant to the PPO family of herbicides. Maize transformants were produced via butafenacil selection using a flexible light regime to increase selection pressure. Butafenacil selection per se did not change transgene copy number distribution relative to other selectable marker systems, but the most tolerant events identified in the greenhouse were more likely to contain multiple copies of the introduced mutant PPO gene. To date, more than 2,500 independent transgenic maize events have been produced using butafenacil selection. The high frequency of A. tumefaciens-mediated transformation via PPO selection enabled us to obtain single-copy transgenic maize lines tolerant to field levels of butafenacil.
Interaction of Cadmium with Glutathione and Photosynthesis in Developing Leaves and Chloroplasts of Phragmites australis (Cav.) Trin. ex Steudel
Authors: Pietrini Fabrizio , Iannelli Maria A. , Pasqualini Stefania , Massacci Angelo 
Published: October 2003

Abstract
We investigated how the presence of cadmium (Cd) at the emergence of Phragmites australis Trin. (Cav.) ex Steudel plants from rhizomes interacted with leaf and chloroplast physiological and biochemical processes. About 8.5 nmol Cd mg–1 chlorophyll was found in leaves, and 0.83 nmol Cd mg–1 chlorophyll was found in chloroplasts of plants treated with 50 μm Cd. As a result, a 30% loss of chlorophyll was measured concomitantly with a comparable percentage reduction in light-saturated photosynthesis. Rubisco content and activity were lowered by 10% and 60%, respectively. Antioxidant activity was stimulated by Cd treatment and was associated with an increase in the glutathione and pyridine pools, and with a larger pool of reduced glutathione. It is suggested that the glutathione pool and its predominance in the reduced state protected the activity of many key photosynthetic enzymes against the thiophilic binding of Cd. Chloroplast ultrastructure was not significantly altered with 50 μm treatment and the efficiency of photosystem II, measured as the fluorescence ratio Fv/Fm, remained high because F0 and Fm were proportionally decreased. In plants treated with 100 μm Cd, all effects were exacerbated, but Fv/Fm remained close to that of control leaves and the glutathione and pyridine nucleotides pools were lowered. The results suggest that glutathione exerted a direct important protective role on photosynthesis in the presence of Cd.
The Nitrilase ZmNIT2 Converts Indole-3-Acetonitrile to Indole-3-Acetic Acid
Authors: Park Woong June , Kriechbaumer Verena , Müller Axel , Piotrowski Markus , Meeley Robert B. , Gierl Alfons , Glawischnig Erich 
Published: October 2003

Abstract
We isolated two nitrilase genes, ZmNIT1 and ZmNIT2, from maize (Zea mays) that share 75% sequence identity on the amino acid level. Despite the relatively high homology to Arabidopsis NIT4, ZmNIT2 shows no activity toward β-cyano-alanine, the substrate of Arabidopsis NIT4, but instead hydrolyzes indole-3-acetonitrile (IAN) to indole-3-acetic acid (IAA). ZmNIT2 converts IAN to IAA at least seven to 20 times more efficiently than AtNIT1/2/3. Quantitative real-time polymerase chain reaction revealed the gene expression of both nitrilases in maize kernels where high concentrations of IAA are synthesized tryptophan dependently. Nitrilase protein and endogenous nitrilase activity are present in maize kernels together with the substrate IAN. These results suggest a role for ZmNIT2 in auxin biosynthesis.
Functional Dissections between GAMYB and Dof Transcription Factors Suggest a Role for Protein-Protein Associations in the Gibberellin-Mediated Expression of the RAmy1A Gene in the Rice Aleurone
Authors: Washio Kenji 
Published: October 2003

Abstract
In the germinated cereal aleurone layer, gibberellic acids (GA) induce expression of a number of genes encoding hydrolytic enzymes that participate in the mobilization of stored molecules. Previous analyses suggest that the key events controlling the GA-regulated gene expression in the aleurone are formation of active transcription machinery referred to as the GA responsive complex, followed by recruiting GAMYB. In general, bipartite promoter contexts composed of the GA-responsive element and the pyrimidine box are observed within the regulatory regions of cereal GA-responsive genes. Protein factors that recognize each promoter sequence were identified and distinct effects on the GA-mediated activation of gene expression have been also investigated; however, the connection and intercalation between two promoter motifs remain obscure. In this study, I have evaluated cooperative function of GAMYB and a pyrimidine box-binding protein OsDOF3 that influenced the promoter activity of the most predominant GA-responsive gene (RAmy1A) of rice (Oryza sativa). Transient expression of OsDOF3 in the germinated aleurone prolonged GAMYB function on the reporter expression in the absence of GA. The synergistic effect required a set of DNA bindings of two proteins on the RAmy1A promoter region. The yeast two-hybrid assay showed the physical interaction of GAMYB and OsDOF3 in yeast cells, indicating that the association of GAMYB and OsDOF3 may be a functional unit in transcription regulation. The results showed the accessory function of OsDOF3 responsible for a dosage-dependent mediation of GA signaling that leads to high-level expression of physiological target genes.
Factors Influencing the Recombinational Expansion and Spread of Telomeric Tandem Arrays in
Kluyveromyces lactis
Authors: Natarajan Shobhana , Groff-Vindman Cindy , McEachern Michael J. 
Published: October 2003

ABSTRACT

We have previously shown that DNA circles containing telomeric repeats and a marker gene can promote the recombinational elongation of telomeres in
Kluyveromyces lactis
by a mechanism proposed to involve rolling-circle DNA synthesis. Wild-type cells acquire a long tandem array at a single telomere, while telomerase deletion (
ter1-
Δ) cells, acquire an array and also spread it to multiple telomeres. In this study, we further examine the factors that affect the formation and spread of telomeric tandem arrays. We show that a telomerase
+
strain with short telomeres and high levels of subtelomeric gene conversion can efficiently form and spread arrays, while a telomere fusion mutant is not efficient at either process. This indicates that an elevated level of gene conversion near telomeres is required for spreading but that growth senescence and a tendency to elongate telomeres in the absence of exogenously added circles are not. Surprisingly, telomeric repeats are frequently deleted from a transforming
URA3
-telomere circle at or prior to the time of array formation by a mechanism dependent upon the presence of subtelomeric DNA in the circle. We further show that in a
ter1-
Δ strain, long tandem arrays can arise from telomeres initially containing a single-copy insert of the
URA3
-telomere sequence. However, the reduced rate of array formation in such strains suggests that single-copy inserts are not typical intermediates in arrays formed from
URA3
-telomere circles. Using heteroduplex circles, we have demonstrated that either strand of a
URA3
-telomere circle can be utilized to form telomeric tandem arrays. Consistent with this, we demonstrate that 100-nucleotide single-stranded telomeric circles of either strand can promote recombinational telomere elongation.
Chromosome Pairing Does Not Contribute to Nuclear Architecture in Vegetative Yeast Cells
Authors: Lorenz Alexander , Fuchs Jörg , Bürger Reinhard , Loidl Josef 
Published: October 2003

ABSTRACT
There are several reports of a closer-than-random colocalization of homologous chromosomes in the vegetative nuclei of diploid budding yeast. Here, we studied by fluorescence in situ hybridization (FISH) the nuclear distribution of chromosomes and found a slight tendency toward closer proximity between homologous (allelic) loci than between any nonhomologous chromosomal regions. We show that most of this preferential association is not due to vegetative (also known as somatic) pairing but is caused by the polar orientation of interphase chromosomes (Rabl orientation). We quantified the occasional loss of detectable fluorescence signals that is inherent to the FISH method. Signal loss leads to the occurrence of a single signal that may be misinterpreted as the close association of two homologous chromosomal sites. The nuclear distribution of homologous loci, when corrected for the influence of nuclear architecture and methodological faults, was not different or was only marginally different from a random relative positioning as predicted by computer simulation. We discuss here several possibilities for the residual homologous proximity that do not invoke homology-dependent vegetative pairing, and we conclude that, in diploid budding yeast, constitutive vegetative pairing is a negligible factor for the organization of the interphase nucleus.
Fission Yeast Sap1 Protein Is Essential for Chromosome Stability
Authors: de Lahondès Raynald , Ribes Veronique , Arcangioli Benoit 
Published: October 2003

ABSTRACT

Sap1 is a dimeric sequence-specific DNA binding-protein, initially identified for its role in mating-type switching of the fission yeast
Schizosaccharomyces pombe
. The protein is relatively abundant, around 10,000 dimers/cell, and is localized in the nucleus.
sap1
+
is essential for viability, and transient overexpression is accompanied by rapid cell death, without an apparent checkpoint response and independently of mating-type switching. Time lapse video microscopy of living cells revealed that the loss of viability is accompanied by abnormal mitosis and chromosome fragmentation. Overexpression of the C terminus of Sap1 induces minichromosome loss associated with the “cut” phenotype (uncoupling mitosis and cytokinesis). These phenotypes are favored when the C terminus of Sap1 is overexpressed during DNA replication. Fluorescence in situ hybridization experiments demonstrated that the cut phenotype is related to precocious centromere separation, a typical marker for loss of cohesion. We propose that Sap1 is an architectural chromatin-associated protein, required for chromosome organization.
Regulation of
ENA1
Na
+
-ATPase Gene Expression by the Ppz1 Protein Phosphatase Is Mediated by the Calcineurin Pathway
Authors: Ruiz Amparo , Yenush Lynne , Ariño Joaquín 
Published: October 2003

ABSTRACT

Saccharomyces cerevisiae
strains lacking the Ppz1 protein phosphatase are salt tolerant and display increased expression of the
ENA1
Na
+
-ATPase gene, a major determinant for sodium extrusion, while cells devoid of the similar Ppz2 protein do not show these phenotypes. However, a
ppz1 ppz2
mutant displays higher levels of
ENA1
expression than the
ppz1
strain. We show here that the increased activity of the
ENA1
promoter in a
ppz1 ppz2
mutant maps to two regions: one region located at −751 to −667, containing a calcineurin-dependent response element (CDRE), and one downstream region (−573 to −490) whose activity responds to intracellular alkalinization. In contrast, the increased
ENA1
expression in a
ppz1
mutant is mediated solely by an intact calcineurin/Crz1 signaling pathway, on the basis that (i) this effect maps to a single region that contains the CDRE and (ii) it is blocked by the calcineurin inhibitor FK506, as well as by deletion of the
CNB1
or
CRZ1
gene. The calcineurin dependence of the increased
ENA1
expression of a
ppz1
mutant would suggest that Ppz1 could negatively regulate calcineurin activity. In agreement with this notion, a
ppz1
strain is calcium sensitive, and this mutation does not result in a decrease in the calcium hypertolerance of a
cnb1
mutant. It has been shown that
ENA1
can be induced by alkalinization of the medium and that a
ppz1 ppz2
strain has a higher intracellular pH. However, we present several lines of evidence that show that the gene expression profile of a
ppz1
mutant does not involve an alkalinization effect. In conclusion, we have identified a novel role for calcineurin, but not alkalinization, in the control of
ENA1
expression in
ppz1
mutants.
Dehydration‐Toughing Dual‐Solvent Gels with Viscoelastic Transition for Infectious Wound Treatment
Authors: Wang Liangyu , Liu Kuilong , Cui Shuai , Qiu Lin , Yang Dongzhi , Nie Jun , Ma Guiping 
Published: January 2024

AbstractThe modulus of traditional biomedical hydrogels increases exponentially meditated by dehydration‐stiffing mechanism, which leads to the failure of interface matching between hydrogels and soft tissue wounds. It is found in the study that the dual‐solvent gels exhibit dehydration‐toughening mechanism with the slowly increasing modulus that are always match the soft tissue wounds. Therefore, dual‐solvent glycerol hydrogels (GCFen‐gly DGHs) are prepared with hydrophobically modified catechol chitosan (hmCSC) and gelatin based on the supramolecular interactions. GCFen‐gly DGHs exhibit excellent water retention capacity with a total solvent content exceeding 80%, permanent skin‐like modulus within a range of 0.45 to 4.13 kPa, and stable photothermal antibacterial abilities against S, aureus, E. coli, as well as MRSA. Infectious full‐thickness rat skin defect model and tissue section analysis indicate that GCFen‐gly DGHs are able to accelerate infectious wound healing by alleviating the inflammatory response, promoting granulation tissue growth, re‐epithelialization, collagen deposition, and vascular regeneration. As a result, GCFen‐gly DGHs is expected to become the next‐generation biological gel materials for infectious wound treatment.
Development of Inverse‐Opal‐Structured Charge‐Deficient Co9S8@nitrogen‐Doped‐Carbon to Catalytically Enable High Energy and High Power for the Two‐Electron Transfer I+/I− Electrode
Authors: Hu Tao , Zhao Yuanyuan , Yang Yihan , Lv Haiming , Zhong Rong , Ding Feng , Mo Funian , Hu Haibo , Zhi Chunyi , Liang Guojin 
Published: January 2024

AbstractThe iodine (I) electrode involving two‐electron transfer chemistry by converting between I+ and I−, has the potential to deliver theoretically doubled capacity and higher working voltage platforms, thus achieving higher energy density. However, owing to the slow kinetics of the cascade two‐electron transfer reactions, the system suffers from large overpotentials and low power density, especially at high working currents and low temperatures. Here, an inverse‐opal‐structured cobalt sulfide@nitrogen‐doped‐carbon (Co9S8@NC) catalyst with unique charge‐deficient states is developed to promote the reaction kinetics of the I−/I+ electrode. The charge‐deficient Co9S8@NC catalyst not only enables strong physicochemical adsorption with the iodine species but also significantly reduces the activation energy and interfacial charge transfer resistance of the cascade I+/I0/I− conversion reaction. Consequently, the prototypical Zn‖I+/I0/I− battery equipped with the Co9S8@NC catalyst can deliver a high energy density of 554 Wh kg−1 and a stable cycle life of 5000 cycles at 30 °C. Moreover, at a subzero temperature of −30 °C, the battery can exhibit enhanced kinetics and a high power density of 1514 W kg−1, high energy density of 485 Wh kg−1.
Boron‐ and Silane‐Based Electron Transport–Type Host Materials for Long‐Lifetime Blue Phosphorescent Organic Light‐Emitting Diodes
Authors: Park Jinho , Moon Junyoung , Jo Unhyeok , Han Seungwon , Lee Dong Ryun , Ahn Han Jin , Kim Jun Yun , Baek Ji‐Ho , Lee Jun Yeob 
Published: January 2024

AbstractDeveloping new host materials is crucial to enhance the performance of blue organic light‐emitting diodes (OLEDs), but achieving long operational lifetimes for OLEDs has been challenging. In this study, boron‐ and silane‐based electron transport–type (n‐type) host materials, 5,9‐dioxa‐13b‐boranaphtho[3,2,1‐de]anthracen‐7‐yltriphenylsilane (BO‐pSi) and 2,12‐bis(triphenylsilyl)‐5,9‐dioxa‐13b‐boranaphtho[3,2,1‐de]anthracene (BO‐2mSi), derived from boron‐ and oxygen‐based 5,9‐dioxa‐13b‐boranaphtho[3,2,1‐de]anthracene (DOBNA) are developed. The DOBNA derivatives are modified with a triphenylsilyl blocking group to alleviate intermolecular interactions arising from the planar structure of DOBNA. The DOBNA derivatives maintain high triplet energy even in the solid state and show thermally activated delayed fluorescence features with electron transport properties. BO‐pSi is used as an n‐type host and exhibits a long operational lifetime of ≈5000 h up to 50% of the initial luminance of blue phosphorescent OLEDs. Furthermore, BO‐2mSi demonstrates a high external quantum efficiency of 7.1%, a small full width at half maximum of 33 nm, and a pure‐violet color coordinate of (0.16, 0.02) while maintaining color purity even at high doping concentrations up to 50 wt%.
Nanoparticle Targeting in Chemo‐Resistant Ovarian Cancer Reveals Dual Axis of Therapeutic Vulnerability Involving Cholesterol Uptake and Cell Redox Balance
Authors: Wang Yinu , Calvert Andrea E. , Cardenas Horacio , Rink Jonathon S. , Nahotko Dominik , Qiang Wenan , Ndukwe C. Estelle , Chen Fukai , Keathley Russell , Zhang Yaqi , Cheng Ji‐Xin , Thaxton C. Shad , Matei Daniela 
Published: January 2024

AbstractPlatinum (Pt)‐based chemotherapy is the main treatment for ovarian cancer (OC); however, most patients develop Pt resistance (Pt‐R). This work shows that Pt‐R OC cells increase intracellular cholesterol through uptake via the HDL receptor, scavenger receptor type B‐1 (SR‐B1). SR‐B1 blockade using synthetic cholesterol‐poor HDL‐like nanoparticles (HDL NPs) diminished cholesterol uptake leading to cell death and inhibition of tumor growth. Reduced cholesterol accumulation in cancer cells induces lipid oxidative stress through the reduction of glutathione peroxidase 4 (GPx4) leading to ferroptosis. In turn, GPx4 depletion induces decreased cholesterol uptake through SR‐B1 and re‐sensitizes OC cells to Pt. Mechanistically, GPx4 knockdown causes lower expression of the histone acetyltransferase EP300, leading to reduced deposition of histone H3 lysine 27 acetylation (H3K27Ac) on the sterol regulatory element binding transcription factor 2 (SREBF2) promoter and suppressing expression of this key transcription factor involved in the regulation of cholesterol metabolism. SREBF2 downregulation leads to decreased SR‐B1 expression and diminished cholesterol uptake. Thus, chemoresistance and cancer cell survival under high ROS burden obligates high GPx4 and SR‐B1 expression through SREBF2. Targeting SR‐B1 to modulate cholesterol uptake inhibits this axis and causes ferroptosis in vitro and in vivo in Pt‐R OC.
Advanced Characterization Techniques on Mechanism Understanding and Effect Evaluation in Zinc Anode Protection
Authors: Zhu Yue , Li Haoyu , Rao Yuan , Guo Shaohua , Zhou Haoshen 
Published: January 2024

AbstractThe growing environmental pollution issues and continuous energy dilemma call for high‐performance energy storage systems (ESSs). While the inevitable safety concerns appear and restrict the application of lithium‐ion batteries in large‐scale ESSs. Contrastively, zinc ion batteries (ZIBs) attract increasing attention due to the inherent advantages of high safety, low cost, and environmental friendliness. However, the poor stability and reversibility of Zn anodes bring severe difficulty for its practical application. Considerable efforts are devoted in the anode modification, such as electrolyte adjustment, interfacial engineering, and anode structure design, but there is still a fuzzy field concerning the reaction process, regulation mechanism, and modified effect. Reviewing the history, the development of various electrodes greatly depends on the breakthrough in advanced characterization technologies, while the summarizations of technological advances in the Zn anode are still deficient. Hence, this review concentrates on the recent progress in various characterization techniques and related strategies of anode protection. The information is especially highlighted that each technique can offer the crucial or auxiliary role they play in proving specific issues. Furthermore, the opinions on current limitations and future directions of common characterization techniques are also discussed in detail, aiming to give a comprehensive perspective in designing advanced zinc anodes.