bluuebunny/crossref_metadata_2025_split huggingface dataset:
Down-Regulation of Caffeic Acid O-Methyltransferase in Maize Revisited Using a Transgenic Approach
Authors: Piquemal Joel , Chamayou Simon , Nadaud Isabelle , Beckert Michel , Barrière Yves , Mila Isabelle , Lapierre Catherine , Rigau Joan , Puigdomenech Pere , Jauneau Alain , Digonnet Catherine , Boudet Alain-Michel , Goffner Deborah , Pichon Magalie 
Published: December 2002

Abstract
Transgenic maize (Zea mays) plants were generated with a construct harboring a maize caffeic acidO-methyltransferase (COMT) cDNA in the antisense (AS) orientation under the control of the maize Adh1(alcohol dehydrogenase) promoter. Adh1-driven β-glucuronidase expression was localized in vascular tissues and lignifying sclerenchyma, indicating its suitability in transgenic experiments aimed at modifying lignin content and composition. One line of AS plants, COMT-AS, displayed a significant reduction in COMT activity (15%–30% residual activity) and barely detectable amounts of COMT protein as determined by western-blot analysis. In this line, transgenes were shown to be stably integrated in the genome and transmitted to the progeny. Biochemical analysis of COMT-AS showed: (a) a strong decrease in Klason lignin content at the flowering stage, (b) a decrease in syringyl units, (c) a lowerp-coumaric acid content, and (d) the occurrence of unusual 5-OH guaiacyl units. These results are reminiscent of some characteristics already observed for the maize bm3(brown-midrib3) mutant, as well as for COMT down-regulated dicots. However, as compared with bm3, COMT down-regulation in the COMT-AS line is less severe in that it is restricted to sclerenchyma cells. To our knowledge, this is the first time that an AS strategy has been applied to modify lignin biosynthesis in a grass species.
The sac Mutants of Chlamydomonas reinhardtii Reveal Transcriptional and Posttranscriptional Control of Cysteine Biosynthesis
Authors: Ravina Cristina G. , Chang Chwenn-In , Tsakraklides George P. , McDermott Jeffery P. , Vega Jose M. , Leustek Thomas , Gotor Cecilia , Davies John P. 
Published: December 2002

Abstract
Algae and vascular plants are cysteine (Cys) prototrophs. They are able to import, reduce, and assimilate sulfate into Cys, methionine, and other organic sulfur-containing compounds. Characterization of genes encoding the enzymes required for Cys biosynthesis from the unicellular green alga Chlamydomonas reinhardtii reveals that transcriptional and posttranscriptional mechanisms regulate the pathway. The derived amino acid sequences of the C. reinhardtiigenes encoding 5′-adenylylsulfate (APS) reductase and serine (Ser) acetyltransferase are orthologous to sequences from vascular plants. The Cys biosynthetic pathway of C. reinhardtii is regulated by sulfate availability. The steady-state level of transcripts and activity of ATP sulfurylase, APS reductase, Ser acetyltransferase, and O-acetyl-Ser (thiol) lyase increase when cells are deprived of sulfate. Thesac1 mutation, which impairs C. reinhardtii ability to acclimate to sulfur-deficient conditions, prevents the increase in accumulation of the transcripts encoding these enzymes and also prevents the increase in activity of all the enzymes except APS reductase. The sac2 mutation, which does not affect accumulation of APS reductase transcripts, blocks the increase in APS reductase activity. These results suggest that APS reductase activity is regulated posttranscriptionally in aSAC2-dependent process.
Tip-Growing Cells of the Moss Ceratodon purpureus Are Gravitropic in High-Density Media
Authors: Schwuchow Jochen Michael , Kern Volker Dieter , Sack Fred David 
Published: December 2002

Abstract
Gravity sensing in plants and algae is hypothesized to rely upon either the mass of the entire cell or that of sedimenting organelles (statoliths). Protonemata of the moss Ceratodon purpureus show upward gravitropism and contain amyloplasts that sediment. If moss sensing were whole-cell based, then media denser than the cell should prevent gravitropism or reverse its direction. Cells that were inverted or reoriented to the horizontal displayed distinct negative gravitropism in solutions of iodixanol with densities of 1.052 to 1.320 as well as in bovine serum albumin solutions with densities of 1.037 to 1.184 g cm−3. Studies using tagged molecules of different sizes and calculations of diffusion times suggest that both types of media penetrate through the apical cell wall. Estimates of the density of the apical cell range from 1.004 to 1.085. Because protonemata grow upward when the cells have a density that is lower than the surrounding medium, gravitropic sensing probably utilizes an intracellular mass in moss protonemata. These data provide additional support for the idea that sedimenting amyloplasts function as statoliths in gravitropism.
Targeted Analysis of Orthologous Phytochrome A Regions of the Sorghum, Maize, and Rice Genomes using Comparative Gene-Island Sequencing
Authors: Morishige Daryl T. , Childs Kevin L. , Moore L. David , Mullet John E. 
Published: December 2002

Abstract
A “gene-island” sequencing strategy has been developed that expedites the targeted acquisition of orthologous gene sequences from related species for comparative genome analysis. A 152-kb bacterial artificial chromosome (BAC) clone from sorghum (Sorghum bicolor) encoding phytochrome A (PHYA) was fully sequenced, revealing 16 open reading frames with a gene density similar to many regions of the rice (Oryza sativa) genome. The sequences of genes in the orthologous region of the maize (Zea mays) and rice genomes were obtained using the gene-island sequencing method. BAC clones containing the orthologous maize and ricePHYA genes were identified, sheared, subcloned, and probed with the sorghum PHYA-containing BAC DNA. Sequence analysis revealed that approximately 75% of the cross-hybridizing subclones contained sequences orthologous to those within the sorghum PHYA BAC and less than 25% contained repetitive and/or BAC vector DNA sequences. The complete sequence of four genes, including up to 1 kb of their promoter regions, was identified in the maize PHYA BAC. Nine orthologous gene sequences were identified in the rice PHYA BAC. Sequence comparison of the orthologous sorghum and maize genes aided in the identification of exons and conserved regulatory sequences flanking each open reading frame. Within genomic regions where micro-colinearity of genes is absolutely conserved, gene-island sequencing is a particularly useful tool for comparative analysis of genomes between related species.
Molecular Characterization of an Arabidopsis Acyl-Coenzyme A Synthetase Localized on Glyoxysomal Membranes
Authors: Hayashi Hiroshi , De Bellis Luigi , Hayashi Yasuko , Nito Kazumasa , Kato Akira , Hayashi Makoto , Hara-Nishimura Ikuko , Nishimura Mikio 
Published: December 2002

Abstract
In higher plants, fat-storing seeds utilize storage lipids as a source of energy during germination. To enter the β-oxidation pathway, fatty acids need to be activated to acyl-coenzyme As (CoAs) by the enzyme acyl-CoA synthetase (ACS; EC 6.2.1.3). Here, we report the characterization of an Arabidopsis cDNA clone encoding for a glyoxysomal acyl-CoA synthetase designatedAtLACS6. The cDNA sequence is 2,106 bp long and it encodes a polypeptide of 701 amino acids with a calculated molecular mass of 76,617 D. Analysis of the amino-terminal sequence indicates that acyl-CoA synthetase is synthesized as a larger precursor containing a cleavable amino-terminal presequence so that the mature polypeptide size is 663 amino acids. The presequence shows high similarity to the typical PTS2 (peroxisomal targeting signal 2). TheAtLACS6 also shows high amino acid identity to prokaryotic and eukaryotic fatty acyl-CoA synthetases. Immunocytochemical and cell fractionation analyses indicated that theAtLACS6 is localized on glyoxysomal membranes.AtLACS6 was overexpressed in insect cells and purified to near homogeneity. The purified enzyme is particularly active on long-chain fatty acids (C16:0). Results from immunoblot analysis revealed that the expression of both AtLACS6 and β-oxidation enzymes coincide with fatty acid degradation. These data suggested that AtLACS6 might play a regulatory role both in fatty acid import into glyoxysomes by making a complex with other factors, e.g. PMP70, and in fatty acid β-oxidation activating the fatty acids.
Characterization of Three Maize Bacterial Artificial Chromosome Libraries toward Anchoring of the Physical Map to the Genetic Map Using High-Density Bacterial Artificial Chromosome Filter Hybridization
Authors: Yim Young-Sun , Davis Georgia L. , Duru Ngozi A. , Musket Theresa A. , Linton Eric W. , Messing Joachim W. , McMullen Michael D. , Soderlund Carol A. , Polacco Mary L. , Gardiner Jack M. , Coe Edward H. 
Published: December 2002

Abstract
Three maize (Zea mays) bacterial artificial chromosome (BAC) libraries were constructed from inbred line B73. High-density filter sets from all three libraries, made using different restriction enzymes (HindIII,EcoRI, and MboI, respectively), were evaluated with a set of complex probes including the185-bp knob repeat, ribosomal DNA, two telomere-associated repeat sequences, four centromere repeats, the mitochondrial genome, a multifragment chloroplast DNA probe, and bacteriophage λ. The results indicate that the libraries are of high quality with low contamination by organellar and λ-sequences. The use of libraries from multiple enzymes increased the chance of recovering each region of the genome. Ninety maize restriction fragment-length polymorphism core markers were hybridized to filters of the HindIII library, representing 6× coverage of the genome, to initiate development of a framework for anchoring BAC contigs to the intermated B73 × Mo17 genetic map and to mark the bin boundaries on the physical map. All of the clones used as hybridization probes detected at least three BACs. Twenty-two single-copy number core markers identified an average of 7.4 ± 3.3 positive clones, consistent with the expectation of six clones. This information is integrated into fingerprinting data generated by the Arizona Genomics Institute to assemble the BAC contigs using fingerprint contig and contributed to the process of physical map construction.
Comparative Sequence Analysis of the Sorghum RphRegion and the Maize Rp1 Resistance Gene Complex
Authors: Ramakrishna Wusirika , Emberton John , SanMiguel Phillip , Ogden Matthew , Llaca Victor , Messing Joachim , Bennetzen Jeffrey L. 
Published: December 2002

Abstract
A 268-kb chromosomal segment containing sorghum (Sorghum bicolor) genes that are orthologous to the maize (Zea mays) Rp1 disease resistance (R) gene complex was sequenced. A region of approximately 27 kb in sorghum was found to contain five Rp1 homologs, but most have structures indicating that they are not functional. In contrast, maize inbred B73 has 15 Rp1 homologs in two nearby clusters of 250 and 300 kb. As at maize Rp1, the cluster of R gene homologs is interrupted by the presence of several genes that appear to have no resistance role, but these genes were different from the ones found within the maize Rp1complex. More than 200 kb of DNA downstream from the sorghumRp1-orthologous R gene cluster was sequenced and found to contain many duplicated and/or truncated genes. None of the duplications currently exist as simple tandem events, suggesting that numerous rearrangements were required to generate the current genomic structure. Four truncated genes were observed, including one gene that appears to have both 5′ and 3′ deletions. The maize Rp1region is also unusually enriched in truncated genes. Hence, the orthologous maize and sorghum regions share numerous structural features, but all involve events that occurred independently in each species. The data suggest that complex R gene clusters are unusually prone to frequent internal and adjacent chromosomal rearrangements of several types.
Gramene, a Tool for Grass Genomics
Authors: Ware Doreen H. , Jaiswal Pankaj , Ni Junjian , Yap Immanuel V. , Pan Xioakang , Clark Ken Y. , Teytelman Leonid , Schmidt Steven C. , Zhao Wei , Chang Kuan , Cartinhour Sam , Stein Lincoln D. , McCouch Susan R. 
Published: December 2002

Abstract
Gramene (http://www.gramene.org) is a comparative genome mapping database for grasses and a community resource for rice (Oryza sativa). It combines a semi-automatically generated database of cereal genomic and expressed sequence tag sequences, genetic maps, map relations, and publications, with a curated database of rice mutants (genes and alleles), molecular markers, and proteins. Gramene curators read and extract detailed information from published sources, summarize that information in a structured format, and establish links to related objects both inside and outside the database, providing seamless connections between independent sources of information. Genetic, physical, and sequence-based maps of rice serve as the fundamental organizing units and provide a common denominator for moving across species and genera within the grass family. Comparative maps of rice, maize (Zea mays), sorghum (Sorghum bicolor), barley (Hordeum vulgare), wheat (Triticum aestivum), and oat (Avena sativa) are anchored by a set of curated correspondences. In addition to sequence-based mappings found in comparative maps and rice genome displays, Gramene makes extensive use of controlled vocabularies to describe specific biological attributes in ways that permit users to query those domains and make comparisons across taxonomic groups. Proteins are annotated for functional significance using gene ontology terms that have been adopted by numerous model species databases. Genetic variants including phenotypes are annotated using plant ontology terms common to all plants and trait ontology terms that are specific to rice. In this paper, we present a brief overview of the search tools available to the plant research community in Gramene.
Genetic Complexity of Cellulose Synthase A Gene Function in Arabidopsis Embryogenesis
Authors: Beeckman Tom , Przemeck Gerhard K.H. , Stamatiou George , Lau Rachel , Terryn Nancy , De Rycke Riet , Inzé Dirk , Berleth Thomas 
Published: December 2002

AbstractThe products of the cellulose synthase A (CESA) gene family are thought to function as isoforms of the cellulose synthase catalytic subunit, but for most CESA genes, the exact role in plant growth is still unknown. Assessing the function of individual CESA genes will require the identification of the null-mutant phenotypes and of the gene expression profiles for each gene. Here, we report that only four of 10 CESA genes,CESA1, CESA2, CESA3, andCESA9 are significantly expressed in the Arabidopsis embryo. We further identified two new mutations in the RADIALLY SWOLLEN1 (RSW1/CESA1) gene of Arabidopsis that obstruct organized growth in both shoot and root and interfere with cell division and cell expansion already in embryogenesis. One mutation is expected to completely abolish the enzymatic activity of RSW1(CESA1) because it eliminated one of three conserved Asp residues, which are considered essential for β-glycosyltransferase activity. In this presumed null mutant, primary cell walls are still being formed, but are thin, highly undulated, and frequently interrupted. From the heart-stage onward, cell elongation in the embryo axis is severely impaired, and cell width is disproportionally increased. In the embryo, CESA1,CESA2, CESA3, and CESA9are expressed in largely overlapping domains and may act cooperatively in higher order complexes. The embryonic phenotype of the presumedrsw1 null mutant indicates that the RSW1(CESA1) product has a critical, nonredundant function, but is nevertheless not strictly required for primary cell wall formation.
Cloning of β-Primeverosidase from Tea Leaves, a Key Enzyme in Tea Aroma Formation
Authors: Mizutani Masaharu , Nakanishi Hidemitsu , Ema Jun-ichi , Ma Seung-Jin , Noguchi Etsuko , Inohara-Ochiai Misa , Fukuchi-Mizutani Masako , Nakao Masahiro , Sakata Kanzo 
Published: December 2002

Abstract
A β-primeverosidase from tea (Camellia sinensis) plants is a unique disaccharide-specific glycosidase, which hydrolyzes aroma precursors of β-primeverosides (6-O-β-d-xylopyranosyl-β-d-glucopyranosides) to liberate various aroma compounds, and the enzyme is deeply concerned with the floral aroma formation in oolong tea and black tea during the manufacturing process. The β-primeverosidase was purified from fresh leaves of a cultivar for green tea (C. sinensis varsinensis cv Yabukita), and its partial amino acid sequences were determined. The β-primeverosidase cDNA has been isolated from a cDNA library of cv Yabukita using degenerate oligonucleotide primers. The cDNA insert encodes a polypeptide consisting of an N-terminal signal peptide of 28 amino acid residues and a 479-amino acid mature protein. The β-primeverosidase protein sequence was 50% to 60% identical to β-glucosidases from various plants and was classified in a family 1 glycosyl hydrolase. The mature form of the β-primeverosidase expressed in Escherichia coli was able to hydrolyze β-primeverosides to liberate a primeverose unit and aglycons, but did not act on 2-phenylethyl β-d-glucopyranoside. These results indicate that the β-primeverosidase selectively recognizes the β-primeverosides as substrates and specifically hydrolyzes the β-glycosidic bond between the disaccharide and the aglycons. The stereochemistry for enzymatic hydrolysis of 2-phenylethyl β-primeveroside by the β-primeverosidase was followed by 1H-nuclear magnetic resonance spectroscopy, revealing that the enzyme hydrolyzes the β-primeveroside by a retaining mechanism. The roles of the β-primeverosidase in the defense mechanism in tea plants and the floral aroma formation during tea manufacturing process are also discussed.
Eyewitness memory for arousing events: putting things into context
Authors: Brown Jeffrey M. 
Published: December 2002

AbstractIf attention is focused on central details at high levels of arousal, memory for peripheral details should be diminished (Easterbrook, 1959). If this is the case, contextual reinstatement (CR) procedures should not enhance memory because these procedures specifically use peripheral information to cue memory. The present experiment tested how arousal influenced eyewitness memory for an event and how it interacts with CR procedures. Participants first viewed one of three series of slides (neutral, arousal, or unusual/control). Memory for central and peripheral details was tested via photo lineups and recognition tests. Although CR procedures enhanced recognition memory for non‐arousing and unusual events, they did not affect recognition memory for arousing events. Analyses of the peripheral photo lineup and peripheral recognition test data revealed that CR enhanced the hit rate for the neutral and unusual conditions but not for the arousal condition. Although CR procedures tended to enhance recognition of central information (increasing the hit rate and decreasing the false alarm rate), CR had a smaller enhancement effect in the arousal condition relative to the neutral and unusual conditions. The present experiment also replicates the Christianson and Loftus (1991) finding that peripheral information is not remembered as well in an arousing event, as compared to memory of neutral and unusual events. The theoretical and applied implications of these results are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Gaucher disease: In vivo evidence for allele dose leading to neuronopathic and nonneuronopathic phenotypes
Authors: Zhao Huiquan , Bailey Laurie A. , Elsas Louis J. , Grinzaid Karen A. , Grabowski Gregory A. 
Published: December 2002

AbstractGaucher disease, a common lysosomal storage disorder, is associated with mutations at the acid β‐glucosidase (GCase) locus. Two affected individuals are described to share a common mutant allele, but manifest different clinical categorical phenotypes. A 57‐year‐old female, with Gaucher disease type 1 and Cherokee ancestry, was homozygous for a rare mutant allele encoding Lys79Asn (K79N). A 2‐year‐old Caucasian male, with Gaucher disease type 3 and Cherokee ancestry, was a heteroallelic homozygote for this same allele (K79N) and a novel complex mutation (null allele). The shared alleles were identical as determined by complete gene sequencing, suggesting a founder effect. The discrepant phenotypes (types 1 and 3) in these two patients provide support for a threshold of residual activity necessary to “protect” the central nervous system (CNS) from the pathogenic effects of Gaucher disease, indicating an allele dose‐effect. Designation of genotype associations with specific phenotypes must be assessed with this perspective. © 2003 Wiley‐Liss, Inc.
Congenital myopathy, recurrent secretory diarrhea, bullous eruption of skin, microcephaly, and deafness: A new genetic syndrome?
Authors: Levy J. , Chung W. , Garzon M. , Gallagher M.P. , Oberfield S.E. , Lieber E. , Anyane‐Yeboa K. 
Published: December 2002

AbstractWe describe three siblings with congenital myopathy, bullous eruption of the skin, secretory diarrhea, apparent zinc deficiency, failure to thrive, deafness, and microcephaly. The parents are not consanguineous and there are no other affected relatives. This new syndrome, which follows an apparent autosomal recessive pattern, appears to be distinct from known syndromes of secretory diarrhea, myopathy, deafness, microcephaly, and zinc deficiency. © 2003 Wiley‐Liss, Inc.
De novo dup(X)(q22.3q26) in a girl with evidence that functional disomy of X material is the cause of her abnormal phenotype
Authors: Armstrong Linlea , McGowan‐Jordan Jean , Brierley Kathleen , Allanson Judith E. 
Published: December 2002

AbstractThe relationship between phenotype and Xq duplications in females remains unclear. Some females are normal; some have short stature; and others have features such as microcephaly, developmental delay/mental retardation, body asymmetries, and gonadal dysgenesis. There are several hypotheses proposed in the literature to explain this variability. We describe a 7‐year‐old girl with dup(X)(q22.3q26). The pregnancy was complicated by intrauterine growth retardation, and she was distressed during labor. During her first year she fed poorly and failed to thrive. She has microcephaly, her height is at the 10th centile, and her hands and feet are strikingly small. She is hypotonic and delayed. Asymmetries of muscle power, and of leg and foot length have been noted. She has mild unilateral ptosis. She has some features of Turner syndrome, and multiple other minor anomalies such as flat labia. These are features common to other described females. This report describes our patient in detail and compares her phenotype to those of the other females with Xq duplications, displays our laboratory investigations, and discusses ideas regarding the pathogenesis of phenotype. The duplicated X is of paternal origin. It is inactivated in all cells; however, the distal duplicated portion appears to be active. We suggest that functional disomy of the duplicated X material, due to local escape from inactivation, may be responsible for the phenotype in the affected females. © 2002 Wiley‐Liss, Inc.