bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gene-Specific Changes in α-Tubulin Transcript Accumulation in Developing Cotton Fibers
Authors: Whittaker David J. , Triplett Barbara A. 
Published: July 2002

Abstract
The fibers of cotton (Gossypium hirsutum) are single-cell trichomes that undergo rapid and synchronous elongation. Cortical microtubules provide spatial information necessary for the alignment of cellulose microfibrils that confine and regulate cell elongation. We used gene-specific probes to investigate α-tubulin transcript levels in elongating cotton fibers. Two discrete patterns of transcript accumulation were observed. Whereas transcripts of α-tubulin genes GhTua2/3 and GhTua4 increased in abundance from 10 to 20 d post anthesis (DPA), GhTua1 and GhTua5 transcripts were abundant only through to 14 DPA, and dropped significantly at 16 DPA with the onset of secondary wall synthesis. This is the first report, to our knowledge, of gene-specific changes in tubulin transcript levels during the development of a terminally differentiated plant cell. The decrease in abundance of GhTua1 and GhTua5 transcripts was correlated with pronounced changes in cell wall structure, suggesting that α-tubulin isoforms may be functionally distinct in elongating fiber cells. Although total α-tubulin transcript levels were much higher in fiber than several other tissues, including the hypocotyl and pollen, none of the α-tubulins was specific to fiber cells.
Differences in Spatial Expression between 14-3-3 Isoforms in Germinating Barley Embryos
Authors: Testerink Christa , van der Meulen René M. , Oppedijk Berry J. , de Boer Albertus H. , Heimovaara-Dijkstra Sjoukje , Kijne Jan W. , Wang Mei 
Published: July 2002

AbstractThe family of 14-3-3 proteins is ubiquitous in eukaryotes and has been shown to exert an array of functions. We were interested in the possible role of 14-3-3 proteins in seed germination. Therefore, we studied the expression of 14-3-3 mRNA and protein in barley (Hordeum distichum L.) embryos during germination. With the use of specific cDNA probes and antibodies, we could detect individual expression of three 14-3-3 isoforms, 14-3-3A, 14-3-3B, and 14-3-3C. Each homolog was found to be expressed in barley embryos. Whereas protein levels of all three isoforms were constant during germination, mRNA expression was found to be induced upon imbibition of the grains. The induction of14-3-3A gene expression during germination was different from that of14-3-3B and14-3-3C. In situ immunolocalization analysis showed similar spatial expression for 14-3-3A and 14-3-3B, while 14-3-3C expression was markedly different. Whereas 14-3-3A and 14-3-3B were expressed throughout the embryo, 14-3-3C expression was tissue specific, with the strongest expression observed in the scutellum and the L2 layer of the shoot apical meristem. These results show that 14-3-3 homologs are differently regulated in barley embryos, and provide a first step in acquiring more knowledge about the role of 14-3-3 proteins in the germination process.
The Role of Photosynthetic Electron Transport in the Oxidative Degradation of Chloroplastic Glutamine Synthetase
Authors: Palatnik Javier F. , Carrillo Néstor , Valle Estela M. 
Published: July 2002

Abstract
The stability of chloroplastic glutamine synthetase (GS; EC 6.3.1.2) was investigated under photooxidative stress using wheat (Triticum aestivum L.) leaves, chloroplasts, and chloroplast lysates. Illuminated seedlings sprayed with the superoxide radical (O⨪2) propagator methyl viologen showed rapid GS decline dependent on MV concentration and exposure time. Degradation products of approximately 39 and 31 kD were detected when chloroplast lysates containing both stroma and thylakoids were illuminated in the presence of MV or H2O2. In all cases, GS cleavage was prevented by the addition of the electron transport inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Full protection against degradation could also be obtained by the incorporation of chelators or antioxidant enzymes. Maximal rates of degradation required the presence of transition metals and reducing compounds such as NADPH or dithiothreitol. Similar patterns of GS cleavage were obtained when seedlings were exposed to high doses of irradiation. The results indicate that chloroplastic GS is extremely prone to oxidative cleavage, and that reduced transition metals, presumably resulting from the destruction of iron-sulfur clusters by light-generated O⨪2, play a crucial role in the degradation process. The physiological implications of GS lability to oxidative stress are discussed.
Induced Resistance to Pathogenic Fungi in Norway Spruce
Authors: Krokene Paal , Christiansen Erik , Solheim Halvor , Franceschi Vincent Ray , Berryman Alan Andrew 
Published: July 2002

Abstract
Norway spruce (Picea abies) trees (approximately 16 m high) of a single clone were used to study the effects of fungal infection and wounding on induction of resistance to the bark beetle-associated bluestain fungusCeratocystis polonica. A dose-response experiment was designed involving three different dosages of fungal (fungus and wound) and sterile agar (wound) pretreatment inoculations (10, 50, or 100 inoculations/m2 on the stem between 0.8 and 2.0 m high). Three weeks after pretreatment, trees were challenged with a massive C. polonica inoculation (400 inoculations/m2). Control trees that received no pretreatment were heavily colonized and killed by the challenge inoculation. The high and medium fungal pretreatments reduced subsequent fungal colonization success by 76% to 97% relative to the control, and fungal pretreatments protected the trees much more efficiently than sterile agar pretreatments. The protection was demonstrated to be local and not systemic in a subsequent experiment, where trees were pretreated with the medium fungal dosage on the lower bole and challenge inoculated further up the stem. Protection was also demonstrated to be pathogen nonspecific, as trees that had been pretreated with a medium dosage of the root rot fungusHeterobasidion annosum showed enhanced resistance to challenge inoculation with C. polonica.
Identification and Characterization of an 18-Kilodalton, VAMP-Like Protein in Suspension-Cultured Carrot Cells
Authors: Gasparian Marine , Pusterla Michele , Baldan Barbara , Downey Patrick M. , Rossetto Ornella , de Laureto Patrizia Polverino , Filippini Francesco , Terzi Mario , Schiavo Fiorella Lo 
Published: July 2002

AbstractPolyclonal antibodies raised against rat vesicle associated membrane protein-2 (VAMP-2) recognized, in carrot (Daucus carota) microsomes, two major polypeptides of 18 and 30 kD, respectively. A biochemical separation of intracellular membranes by a sucrose density gradient co-localized the two polypeptides as resident in light, dense microsomes, corresponding to the endoplasmic reticulum-enriched fractions. Purification of coated vesicles allowed us to distinguish the subcellular location of the 18-kD polypeptide from that of 30 kD. The 18-kD polypeptide is present in the non-clathrin-coated vesicle peak. Like other VAMPs, the carrot 18-kD polypeptide is proteolyzed by tetanus toxin after separation of coatomers. Amino acid sequence analysis of peptides obtained by digestion of the 18-kD carrot polypeptide with the endoproteinase Asp-N confirms it to be a member of the VAMP family, as is suggested by its molecular weight, vesicular localization, and toxin-induced cleavage.
StGCPRP, a Potato Gene Strongly Expressed in Stomatal Guard Cells, Defines a Novel Type of Repetitive Proline-Rich Proteins
Authors: Menke Ulrich , Renault Nathalie , Mueller-Roeber Bernd 
Published: July 2002

Abstract
Guard cells represent a highly differentiated cell type within the epidermis of plant leaves and stems. They respond to many endogenous and environmental signals and thereby modify the size of the stomatal pore they surround. We identified a novel gene that is highly expressed in guard cells of potato (Solanum tuberosum). It encodes a repetitive proline (Pro)-rich protein of 54 kD (491 amino acids) and was named StGCPRP (S. tuberosum guard cell Pro-rich protein). StGCPRP has a bipartite structure. The C-terminal part of StGCPRP contains a high percentage (46%) of Pro residues organized in distinct repetitive sequence motifs, whereas its extended N terminus is essentially free of Pros. StGCPRP represents the first member of a novel class of hybrid Pro-rich proteins that we designated NHyPRPs. In young but not in mature leaves, StGCPRP transcripts were also present at high levels in mesophyll cells (in addition to guard cells), indicating developmental regulation of StGCPRPgene expression. In addition, StGCPRP expression is regulated by environmental factors, as shown by a decrease inStGCPRP transcript levels under drought stress. Two proteins similar to StGCPRP were found to be encoded by the Arabidopsis genome, indicating that NHyPRPs are more widely distributed in higher plants.
Transgenic Tobacco and Arabidopsis Plants Expressing the Two Multifunctional Sorghum Cytochrome P450 Enzymes, CYP79A1 and CYP71E1, Are Cyanogenic and Accumulate Metabolites Derived from Intermediates in Dhurrin Biosynthesis
Authors: Bak Søren , Olsen Carl Erik , Halkier Barbara Ann , Møller Birger Lindberg 
Published: July 2002

Abstract
Novel cyanogenic plants have been generated by the simultaneous expression of the two multifunctional sorghum (Sorghum bicolor [L.] Moench) cytochrome P450 enzymes CYP79A1 and CYP71E1 in tobacco (Nicotiana tabacum cv Xanthi) and Arabidopsis under the regulation of the constitutive 35S promoter. CYP79A1 and CYP71E1 catalyze the conversion of the parent amino acid tyrosine to p-hydroxymandelonitrile, the aglycone of the cyanogenic glucoside dhurrin. CYP79A1 catalyzes the conversion of tyrosine to p-hydroxyphenylacetaldoxime and CYP71E1, the subsequent conversion top-hydroxymandelonitrile.p-Hydroxymandelonitrile is labile and dissociates intop-hydroxybenzaldehyde and hydrogen cyanide, the same products released from dhurrin upon cell disruption as a result of pest or herbivore attack. In transgenic plants expressing CYP79A1 as well as CYP71E1, the activity of CYP79A1 is higher than that of CYP71E1, resulting in the accumulation of severalp-hydroxyphenylacetaldoxime-derived products in the addition to those derived from p-hydroxymandelonitrile. Transgenic tobacco and Arabidopsis plants expressing only CYP79A1 accumulate the same p-hydroxyphenylacetaldoxime-derived products as transgenic plants expressing both sorghum cytochrome P450 enzymes. In addition, the transgenic CYP79A1 Arabidopsis plants accumulate large amounts ofp-hydroxybenzylglucosinolate. In transgenic Arabidopsis expressing CYP71E1, this enzyme and the enzymes of the pre-existing glucosinolate pathway compete for thep-hydroxyphenylacetaldoxime as substrate, resulting in the formation of small amounts ofp-hydroxybenzylglucosinolate. Cyanogenic glucosides are phytoanticipins, and the present study demonstrates the feasibility of expressing cyanogenic compounds in new plant species by gene transfer technology to improve pest and disease resistance.
Dephosphorylation of Photosystem II Reaction Center Proteins in Plant Photosynthetic Membranes as an Immediate Response to Abrupt Elevation of Temperature
Authors: Rokka Anne , Aro Eva-Mari , Herrmann Reinhold G. , Andersson Bertil , Vener Alexander V. 
Published: July 2002

Abstract
Kinetic studies of protein dephosphorylation in photosynthetic thylakoid membranes revealed specifically accelerated dephosphorylation of photosystem II (PSII) core proteins at elevated temperatures. Raising the temperature from 22°C to 42°C resulted in a more than 10-fold increase in the dephosphorylation rates of the PSII reaction center proteins D1 and D2 and of the chlorophyll abinding protein CP43 in isolated spinach (Spinacia oleracea) thylakoids. In contrast the dephosphorylation rates of the light harvesting protein complex and the 9-kD protein of the PSII (PsbH) were accelerated only 2- to 3-fold. The use of a phospho-threonine antibody to measure in vivo phosphorylation levels in spinach leaves revealed a more than 20-fold acceleration in D1, D2, and CP43 dephosphorylation induced by abrupt elevation of temperature, but no increase in light harvesting protein complex dephosphorylation. This rapid dephosphorylation is catalyzed by a PSII-specific, intrinsic membrane protein phosphatase. Phosphatase assays, using intact thylakoids, solubilized membranes, and the isolated enzyme, revealed that the temperature-induced lateral migration of PSII to the stroma-exposed thylakoids only partially contributed to the rapid increase in the dephosphorylation rate. Significant activation of the phosphatase coincided with the temperature-induced release of TLP40 from the membrane into thylakoid lumen. TLP40 is a peptidyl-prolyl cis-trans isomerase, which acts as a regulatory subunit of the membrane phosphatase. Thus dissociation of TLP40 caused by an abrupt elevation in temperature and activation of the membrane protein phosphatase are suggested to trigger accelerated repair of photodamaged PSII and to operate as possible early signals initiating other heat shock responses in chloroplasts.
Effect of Climate Conditions and Plant Developmental Stage on the Stability of Antibodies Expressed in Transgenic Tobacco
Authors: Stevens Lucas H. , Stoopen Geert M. , Elbers Ingrid J.W. , Molthoff Jos W. , Bakker Hans A.C. , Lommen Arjen , Bosch Dirk , Jordi Wilco 
Published: July 2002

Abstract
Plants are regarded as a promising system for the production of heterologous proteins. However, little is known about the influence of plant physiology and plant development on the yield and quality of the heterologous proteins produced in plants. To investigate this, tobacco (Nicotiana tabacum cv Samsun NN) was transformed with a single construct that contained behind constitutive promotors the light- and heavy-chain genes of a mouse antibody. The in planta stability of the antibody was analyzed in transgenic plants that were grown under high and low irradiation at 15°C and 25°C. High-light conditions favored the production of biomass, of total soluble protein, and of antibody. The plants grown at 25°C developed faster and contained less antibody per amount of leaf tissue than the plants grown at 15°C. Both endogenous protein and antibody content showed a strong decline during leaf development. The heavy chains of the antibody underwent in planta degradation via relatively stable fragments. In vitro incubations of purified plantibody with leaf extracts of wild-type tobacco indicated the involvement of acidic proteases. It is interesting that the same antibody produced by mouse hybridoma cells exhibited higher stability in this in vitro assay. This may be explained by the assumption that the plant type ofN-glycosylation contributes less to the stability of the antibody than the mouse-type of N-glycosylation. The results of this study indicate that proteolytic degradation during plant development can be an important factor affecting yield and homogeneity of heterologous protein produced by transgenic plants.
Sequence Haplotypes Revealed by Sequence-Tagged Site Fine Mapping of theRor1Gene in the Centromeric Region of Barley Chromosome 1H
Authors: Collins Nicholas C. , Lahaye Thomas , Peterhänsel Christoph , Freialdenhoven Andreas , Corbitt Margaret , Schulze-Lefert Paul 
Published: July 2002

AbstractWe describe the development of polymerase chain reaction-based, sequence-tagged site (STS) markers for fine mapping of the barley (Hordeum vulgare) Ror1 gene required for broad-spectrum resistance to powdery mildew (Blumeria graminis f. sp. hordei). After locatingRor1 to the centromeric region of barley chromosome 1H using a combined amplified fragment length polymorphism/restriction fragment-length polymorphism (RFLP) approach, sequences of RFLP probes from this chromosome region of barley and corresponding genome regions from the related grass species oat (Avena spp.), wheat, and Triticum monococcum were used to develop STS markers. Primers based on the RFLP probe sequences were used to polymerase chain reaction-amplify and directly sequence homologous DNA stretches from each of four parents that were used for mapping. Over 28,000 bp from 22 markers were compared. In addition to one insertion/deletion of at least 2.0 kb, 79 small unique sequence polymorphisms were observed, including 65 single nucleotide substitutions, two dinucleotide substitutions, 11 insertion/deletions, and one 5-bp/10-bp exchange. The frequency of polymorphism between any two barley lines ranged from 0.9 to 3.0 kb, and was greatest for comparisons involving an Ethiopian landrace. Haplotype structure was observed in the marker sequences over distances of several hundred basepairs. Polymorphisms in 16 STSs were used to generate genetic markers, scored by restriction enzyme digestion or by direct sequencing. Over 2,300 segregants from three populations were used in Ror1 linkage analysis, mappingRor1 to a 0.2- to 0.5-cM marker interval. We discuss the implications of sequence haplotypes and STS markers for the generation of high-density maps in cereals.
Transgenic Manipulation of the Metabolism of Polyamines in Poplar Cells
Authors: Bhatnagar Pratiksha , Glasheen Bernadette M. , Bains Suneet K. , Long Stephanie L. , Minocha Rakesh , Walter Christian , Minocha Subhash C. 
Published: July 2002

Abstract
The metabolism of polyamines (putrescine, spermidine, and spermine) has become the target of genetic manipulation because of their significance in plant development and possibly stress tolerance. We studied the polyamine metabolism in non-transgenic (NT) and transgenic cells of poplar (Populus nigra ×maximowiczii) expressing a mouse Orn decarboxylase (odc) cDNA. The transgenic cells showed elevated levels of mouse ODC enzyme activity, severalfold higher amounts of putrescine, a small increase in spermidine, and a small reduction in spermine as compared with NT cells. The conversion of labeled ornithine (Orn) into putrescine was significantly higher in the transgenic than the NT cells. Whereas exogenously supplied Orn caused an increase in cellular putrescine in both cell lines, arginine at high concentrations was inhibitory to putrescine accumulation. The addition of urea and glutamine had no effect on polyamines in either of the cell lines. Inhibition of glutamine synthetase by methionine sulfoximine led to a substantial reduction in putrescine and spermidine in both cell lines. The results show that: (a) Transgenic expression of a heterologousodc gene can be used to modulate putrescine metabolism in plant cells, (b) accumulation of putrescine in high amounts does not affect the native arginine decarboxylase activity, (c) Orn biosynthesis occurs primarily from glutamine/glutamate and not from catabolic breakdown of arginine, (d) Orn biosynthesis may become a limiting factor for putrescine production in the odc transgenic cells, and (e) assimilation of nitrogen into glutamine keeps pace with an increased demand for its use for putrescine production.
Sequence and Analysis of the Tomato JOINTLESSLocus
Authors: Mao Long , Begum Dilara , Goff Stephen A. , Wing Rod A. 
Published: July 2002

Abstract
A 119-kb bacterial artificial chromosome from theJOINTLESS locus on the tomato (Lycopersicon esculentum) chromosome 11 contained 15 putative genes. Repetitive sequences in this region include onecopia-like LTR retrotransposon, 13 simple sequence repeats, three copies of a novel type III foldback transposon, and four putative short DNA repeats. Database searches showed that the foldback transposon and the short DNA repeats seemed to be associated preferably with genes. The predicted tomato genes were compared with the complete Arabidopsis genome. Eleven out of 15 tomato open reading frames were found to be colinear with segments on five Arabidopsis bacterial artificial chromosome/P1-derived artificial chromosome clones. The synteny patterns, however, did not reveal duplicated segments in Arabidopsis, where over half of the genome is duplicated. Our analysis indicated that the microsynteny between the tomato and Arabidopsis genomes was still conserved at a very small scale but was complicated by the large number of gene families in the Arabidopsis genome.
Transcriptional Responses in the Hemiparasitic PlantTriphysaria versicolor to Host Plant Signals,
Authors: Matvienko Marta , Torres Manuel J. , Yoder John I. 
Published: July 2002

Abstract
Parasitic plants in the Scrophulariaceae use chemicals released by host plant roots to signal developmental processes critical for heterotrophy. Haustoria, parasitic plant structures that attach to and invade host roots, develop on roots of the hemiparasitic plantTriphysaria versicolor within a few hours of exposure to either maize (Zea mays) root exudate or purified haustoria-inducing factors. We prepared a normalized, subtractive cDNA library enriched for transcripts differentially abundant in T. versicolor root tips treated with the allelopathic quinone 2,6-dimethoxybenzoquinone (DMBQ). Northern analyses estimated that about 10% of the cDNAs represent transcripts strongly up-regulated in roots exposed to DMBQ. Northern and reverse northern analyses demonstrated that most DMBQ-responsive messages were similarly up-regulated in T. versicolor roots exposed to maize root exudates. From the cDNA sequences we assembled a unigene set of 137 distinct transcripts and assigned functions by homology comparisons. Many of the proteins encoded by the transcripts are predicted to function in quinone detoxification, whereas others are more likely associated with haustorium development. The identification of genes transcriptionally regulated by haustorium-inducing factors provides a framework for dissecting genetic pathways recruited by parasitic plants during the transition to heterotrophic growth.
Detection of early gene expression changes during activation of human primary lymphocytes by in vitro synthesis of proteins from polysome‐associated mRNAs
Authors: Miyamoto Suzanne , Qin Jun , Safer Brian 
Published: July 2002

AbstractThe rapid increase in protein synthesis during the mitogenic stimulation of human peripheral blood lymphocyte is the result of global and specific translational control mechanisms. To study some of these mechanisms, we examined the in vitro translatability of mRNAs associated with the polyribosome fraction. Polyribosome fractions were isolated from lymphocytes after activation with ionomycin and the phorbol ester PMA. The associated PAmRNAs were translated in the presence of mRNA‐depleted rabbit reticulocyte lysate and [35S]Met, and the protein products were analyzed by SDS–PAGE and autoradiography. There was little synthesis of protein from the PAmRNAs isolated from unactivated T cells, but the PAmRNAs isolated from activated T cells showed a rapid increase in translatability. Translation of the PAmRNAs was sensitive to edeine and m7GTP, suggesting their cap‐dependent translation. With activation, the majority of proteins showed increasing in vitro translation, but two proteins, p72 and p33, were found to have increased synthesis within 30 min, which decreased in 1 h. Transcription inhibitors were used to ascertain if regulation of their expression was transcriptional or translational. To identify these proteins, we used biotinylated lysine during the in vitro translation reaction, and we extracted the biotinylated protein by using streptavidin magnetic beads. The protein product was analyzed by mass spectrometry. p33 was identified as a prohibitin‐like protein (BAP37), but the identification of p72 was not found in the databases. The distinct up‐regulation and down‐regulation of their protein expression suggest their tightly controlled regulation during early T cell activation.