bluuebunny/crossref_metadata_2025_split huggingface dataset:
The impact of screening on road surface temperature
Authors: Bogren J , Gustavsson T , Karlsson M , Postgård U 
Published: July 2002

AbstractThe effect of screening on road surface temperatures is analysed using data from the Swedish road weather information system (RWIS) together with data from thermal mapping. The study deals with the analysis of temperature variations caused by shading of the road surface during clear daytime conditions and focuses on the relation between solar elevation and magnitude of road surface temperature differences between screened and sun‐exposed areas. Also included is an analysis of how the temperature differences during the day affect the establishment of temperature variations after sunset and the time it takes after sunset for temperature differences caused by shading to decline. The results show that the magnitude of road surface temperature differences between sun exposed and screened sites (RSTdiff) that develop during clear day conditions can be attributed to solar elevation (β) and can be expressed by the equation: RSTdiff = −2.7 + 0.46(β). A relationship between the daily maximum temperature difference and the preservation of the screening effect after sunset is observed. The effect after sunset can be described by: RSTdiff = A − B h + C h2 − D h3 − E h4 + F h5, where h is the time in hours after sunset and A to F are constants related to the time of the year at the actual site. Copyright © 2000 Royal Meteorological Society
The operational Australian ultraviolet index forecast 1997
Authors: Lemus‐Deschamps Lilia , Rikus Lawrie , Gies Peter 
Published: July 2002

AbstractThe Cooperative Research Centre for Southern Hemisphere Meteorology in collaboration with the Bureau of Meteorology has developed an ultraviolet index (UVI) forecast system to support the Australian UVI forecast issued to the public by the Bureau of Meteorology. In an effort to alert the public to the possibility of harmful levels of ultraviolet radiation the UVI forecast has been issued daily as part of the meteorological weather report since spring 1996. The predicted UVI indicates the amount of ultraviolet radiation that will reach the Earth's surface at local noon next day. The forecast includes the effects of cloud cover. The global clear sky UVI is calculated using a two‐stream radiative transfer model and a deterministic ozone forecast scheme. The system utilises meteorological fields from the global numerical weather forecast model of the Bureau of Meteorology. This paper describes the UVI forecast system, and its results are compared with observational data from the Australian Radiation Laboratory for several Australian cities for the period January–December 1997. Possible improvements are outlined since the UVI forecast system is the subject of ongoing development. Copyright © 1999 Royal Meteorological Society
Changes in the Expression and the Enzymic Properties of the 20S Proteasome in Sugar-Starved Maize Roots. Evidence for an in Vivo Oxidation of the Proteasome
Authors: Basset Gilles , Raymond Philippe , Malek Lada , Brouquisse Renaud 
Published: July 2002

Abstract
The 20S proteasome (multicatalytic proteinase) was purified from maize (Zea mays L. cv DEA 1992) roots through a five-step procedure. After biochemical characterization, it was shown to be similar to most eukaryotic proteasomes. We investigated the involvement of the 20S proteasome in the response to carbon starvation in excised maize root tips. Using polyclonal antibodies, we showed that the amount of proteasome increased in 24-h-carbon-starved root tips compared with freshly excised tips, whereas the mRNA levels of α3 and β6 subunits of 20S proteasome decreased. Moreover, in carbon-starved tissues, chymotrypsin-like and caseinolytic activities of the 20S proteasome were found to increase, whereas trypsin-like activities decreased. The measurement of specific activities and kinetic parameters of 20S proteasome purified from 24-h-starved root tips suggested that it was subjected to posttranslational modifications. Using dinitrophenylhydrazine, a carbonyl-specific reagent, we observed an increase in carbonyl residues in 20S proteasome purified from starved root tips. This means that 20S proteasome was oxidized during starvation treatment. Moreover, an in vitro mild oxidative treatment of 20S proteasome from non-starved material resulted in the activation of chymotrypsin-like, peptidyl-glutamyl-peptide hydrolase and caseinolytic-specific activities and in the inhibition of trypsin-like specific activities, similar to that observed for proteasome from starved root tips. Our results provide the first evidence, to our knowledge, for an in vivo carbonylation of the 20S proteasome. They suggest that sugar deprivation induces an oxidative stress, and that oxidized 20S proteasome could be associated to the degradation of oxidatively damaged proteins in carbon starvation situations.
Developmental Stage-Specific and Nitrate-Independent Regulation of Nitrate Reductase Gene Expression in Rapeseed
Authors: Fukuoka H. , Ogawa T. , Minami H. , Yano H. , Ohkawa Y. 
Published: July 2002

Abstract
cDNA clones for two isogenes of nitrate reductase (NR) have been isolated from rapeseed (Brassica napus L.) androgenetic haploid embryos induced by microspore culture. NR mRNA accumulation can be detected by northern hybridization at 14 d after culture initiation when embryos develop to the heart/torpedo-shaped stage. Whole-mount in situ hybridization experiments demonstrate that the mRNA accumulation is developmental stage specific. In addition, even when cultured in media containing no nitrate, embryos accumulated NR mRNA to almost the same level as the control. This indicates the unique regulation of NR in embryogenesis in which NR mRNA transcription is activated in a developmental stage-specific manner that is independent of nitrate induction. In zygotic embryogenesis, a stage-specific accumulation of NR mRNA was also observed. By contrast, the obvious effect of nitrate on NR expression that has been reported in many plant species was also confirmed in rapeseed leaf. Quantitative combined reverse transcription-poly-merase chain reaction analysis suggests that the flexible and variable regulation of NR expression, which is organ specific, nitrogen metabolite specific, and developmental stage specific, is caused principally by regulation of one major structural gene.
Mutualistic Fungal Endophytes Express a Proteinase that Is Homologous to Proteases Suspected to Be Important in Fungal Pathogenicity
Authors: Reddy P. V. , Lam C. K. , Belanger F. C. 
Published: July 2002

Abstract
Many cultivated and wild grass species are hosts to mutualistic fungal endophytes. These associations are ecologically and agronomically significant, yet little is known regarding the physiological aspects of the interaction. In the Poa ampla/Acremonium typhinum interaction, a fungal serine proteinase, At1, is surprisingly abundant and may constitute 1 to 2% of the total leaf-sheath protein. Sequence analysis of cDNA and genomic clones indicates that proteinase At1 is a member of the eukaryotic subtilisin-like protease family. It is homologous to proteases suspected to be virulence factors in fungal pathogens of insects, nematodes, and other fungi. Gel blot analysis of RNA extracted from infected leaf-sheath tissue indicates that the proteinase At1 transcript level is extremely high. RNA gel blots and immunoblots of purified enzymes indicate that similar proteinases are produced by Epichloe festucae and Acremonium lolii, the fungal endophytes infecting Festuca rubra subsp. rubra and Lolium perenne, respectively. Fungal expression of proteinase At1-like enzymes may be a general feature of endophyte infection.
Phosphorylation of Serine-15 of Maize Leaf Sucrose Synthase (Occurrence in Vivo and Possible Regulatory Significance)
Authors: Huber S. C. , Huber J. L. , Liao P. C. , Gage D. A. , McMichael Jr R. W. , Chourey P. S. , Hannah L. C. , Koch K. 
Published: July 2002

Abstract
Experiments were conducted to determine whether sucrose synthase (SuSy) was phosphorylated in the elongation zone of maize (Zea mays L.) leaves. The approximately 90-kD subunit of SuSy was 32P-labeled on seryl residue(s) when excised shoots were fed [32P]orthophosphate. Both isoforms of SuSy (the SS1 and SS2 proteins) were phosphorylated in vivo, and tryptic peptide-mapping analysis suggested a single, similar phosphorylation site in both proteins. A combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and automated Edman sequencing analysis unequivocally identified the phosphorylation site in the maize SS2 protein as serine-15. This site was phosphorylated in vitro by endogenous protein kinase(s) in a strictly Ca2+-dependent manner. A synthetic peptide, based on the phosphorylation site sequence, was used to identify and partially purify an endogenous Ca2+-dependent protein kinase(s) from the maize leaf elongation zone and expanding spinach leaves. Phosphorylation of SuSy in vitro selectively activates the cleavage reaction by increasing the apparent affinity of the enzyme for sucrose and UDP, suggesting that phosphorylation may be of regulatory significance. Conservation of the phosphorylation site, and the sequences surrounding it, among plant species suggests that phosphorylation of SuSy may be widespread, if not universal, in plants.
Differential Expression of Soybean Cysteine Proteinase Inhibitor Genes during Development and in Response to Wounding and Methyl Jasmonate
Authors: Botella M. A. , Xu Y. , Prabha T. N. , Zhao Y. , Narasimhan M. L. , Wilson K. A. , Nielsen S. S. , Bressan R. A. , Hasegawa P. M. 
Published: July 2002

Abstract
Three cysteine proteinase inhibitor cDNA clones (pL1, pR1, and pN2) have been isolated from a soybean (Glycine max L. Merr.) embryo library. The proteins encoded by the clones are between 60 and 70% identical and contain the consensus QxVxG motif and W residue in the appropriate spatial context for interaction with the cysteine proteinase papain. L1, R1, and N2 mRNAs were differentially expressed in different organs of plants (juvenile and mature) and seedlings, although N2 mRNA was constitutive only in flowers. R1 and N2 transcripts were induced by wounding or methyl jasmonate (M-JA) treatment in local and systemic leaves coincident with increased papain inhibitory activity, indicating a role for R1 and N2 in plant defense. The L1 transcript was constitutively expressed in leaves and was induced slightly by M-JA treatment in roots. Unlike the chymotrypsin/trypsin proteinase inhibitor II gene (H. Pena-Cortes, J. Fisahn, L. Willmitzer [1995] Proc Natl Acad Sci USA 92: 4106–4113), expression of the soybean genes was only marginally induced by abscisic acid and only in certain tissues. Norbornadiene, a competitive inhibitor of ethylene binding, abolished the wounding or M-JA induction of R1 and N2 mRNAs but not the accumulation of the wound-inducible vspA transcript. Presumably, ethylene binding to its receptor is involved in the wound inducibility of R1 and N2 but not vspA mRNAs. Bacterial recombinant L1 and R1 proteins, expressed as glutathione S-transferase fusion proteins, exhibited substantial inhibitory activities against vicilin peptidohydrolase, the major thiol endopeptidase in mung bean seedlings. Recombinant R1 protein had much greater cysteine proteinase inhibitor activity than recombinant L1 protein, consistent with the wound inducibility of the R1 gene and its presumed role in plant defense.
Immunopurification and Characterization of a 40-kD 1-Aminocyclopropane-1-Carboxylic Acid N-Malonyltransferase from Mung Bean Seedling Hypocotyls
Authors: Chick WSH. , Leung P. C. 
Published: July 2002

Abstract
1-Aminocylopropane-1-carboxylic acid (ACC) N-malonyltransferase catalyzes the transfer of the malonyl group from malonyl coenzyme A to ACC to form malonyl ACC. Using partially purified ACC N-malonyltransferase from the hypocotyls of mung bean (Vigna radiata) seedlings, we produced two mouse monoclonal antibodies (1H5 and 2G3) to this enzyme. These antibodies bind to sites other than the active site of the enzyme because monoclonal antibody-bound ACC N-malonyltransferase still exhibits full catalytic activity. A monoclonal antibody column was constructed using 1H5 and protein G Sepharose. The ACC N-malonyltransferase purified from this monoclonal antibody column has a molecular mass of 40 kD, which is different from that reported previously. The enzyme has a higher electrophoretic mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the absence of the reducing agent dithiothreitol. The optimum temperature of this 40-kD ACC N-malonyltransferase is 45[deg]C and the apparent Kms for ACC and malonyl coenzyme A are 66.7 and 40 [mu]M, respectively.
Cloning and Overexpression of Two cDNAs Encoding the Low-CO2-lnducible Chloroplast Envelope Protein LIP-36 from Chlamydomonas reinhardtii
Authors: Chen Z. Y. , Lavigne L. L. , Mason C. B. , Moroney J. V. 
Published: July 2002

Abstract
Chlamydomonas reinhardtii, a unicellular green alga, grows photoautotrophically at very low concentrations of inorganic carbon due to the presence of an inducible CO2-concentrating mechanism. During the induction of the CO2-concentrating mechanism at low-CO2 growth conditions, at least five polypeptides that are either absent or present in low amounts in cells grown on high-CO2 concentrations are induced. One of these induced polypeptides with a molecular mass of 36 kD, LIP-36, has been localized to the chloroplast envelope. The protein was purified and the partial internal amino acid sequences were obtained through lys-C digestion. Two cDNAs encoding LIP-36 have been cloned using degenerate primers based on the amino acid sequences. The two genes encoding LIP-36 are highly homologous in the coding region but are completely different in the 5[prime]-end and 3[prime]-end untranslated regions. The deduced protein sequences show strong homology to the mitochondrial carrier protein superfamily, suggesting that LIP-36 is a chloroplast carrier protein. The regulation of the expression of these two genes at high- and low-CO2 growth conditions is also different. Both genes were highly expressed under low-CO2 growth conditions, with the steady-state level of LIP-36 G1 mRNA more abundant. However, neither gene was expressed at high-CO2 growth conditions. The gene products of both clones expressed in Escherichia coli were recognized by an antibody raised against LIP-36, confirming that the two cDNAs indeed encode the C. reinhardtii chloroplast envelope carrier protein LIP-36.
Acidic Phosphoprotein Complex of the 60S Ribosomal Subunit of Maize Seedling Roots (Components and Changes in Response to Flooding)
Authors: Bailey-Serres J. , Vangala S. , Szick K. , Lee CHK. 
Published: July 2002

Abstract
We determined that ribosomes of seedling roots of maize (Zea mays L.) contain the acidic phosphoproteins (P-proteins) known to form a flexible lateral stalk structure of the 60S subunit of eukaryotic ribosomes. The P-protein stalk, composed of P0, P1, and P2, interacts with elongation factors, mRNA, and tRNA during translation. Acidic proteins of 13 to 15.5 kD were released as a complex from ribosomes with 0.4 M NH4Cl/50% ethanol. Protein and cDNA sequence analysis confirmed that maize ribosomes contain one type of P1, two types of P2, and a fourth and novel P1/P2-type protein. This novel P-protein, designated P3, has the conserved C terminus of P1 and P2. P1, P2, and P3 are similar in deduced mass (11.4–12.2 kD) and isoelectric point (4.1–4.3). A 35.5- to 36-kD acidic protein was released at low levels from ribosomes with 1.0 M NH4Cl/50% ethanol and identified as P0. Labeling of roots with [32P]inorganic phosphate confirmed the in vivo phosphorylation of the P-proteins. Flooding caused dynamic changes in the P-protein complex, which affected the potential of ribosome-associated kinases and casein kinase II to phosphorylate the P-proteins. We discuss possible alerations of the ribosomal P-protein complex and consider that these changes may be involved in the selective translation of mRNA in flooded roots.
Sequence Analysis of the Cloned glossy8 Gene of Maize Suggests That It May Code for a β-Ketoacyl Reductase Required for the Biosynthesis of Cuticular Waxes
Authors: Xu X. , Dietrich C. R. , Delledonne M. , Xia Y. , Wen T. J. , Robertson D. S. , Nikolau B. J. , Schnable P. S. 
Published: July 2002

Abstract
The gl8 locus of maize (Zea mays L.) was previously defined by a mutation that reduces the amount and alters the composition of seedling cuticular waxes. Sixty independently derived gl8 mutant alleles were isolated from stocks that carried the Mutator transposon system. A DNA fragment that contains a Mu8 transposon and that co-segregates with one of these alleles, gl8-Mu3142, was identified and cloned. DNA flanking the Mu8 transposon was shown via allelic cross-referencing experiments to represent the gl8 locus. The gl8 probe revealed a 1.4-kb transcript present in wild-type seedling leaves and, in lesser amounts, in other organs and at other developmental stages. The amino acid sequence deduced from an apparently full-length gl8 cDNA exhibits highly significant sequence similarity to a group of enzymes from plants, eubacteria, and mammals that catalyzes the reduction of ketones. This finding suggests that the GL8 protein probably functions as a reductase during fatty acid elongation in the cuticular wax biosynthetic pathway.
Identification of Proliferation-Induced Genes in Arabidopsis thaliana (Characterization of a New Member of the Highly Evolutionarily Conserved Histone H2A.F/Z Variant Subfamily)
Authors: Callard D. , Mazzolini L. 
Published: July 2002

Abstract
The changes in gene expression associated with the reinitiation of cell division and subsequent progression through the cell cycle in Arabidopsis thaliana cell-suspension cultures were investigated. Partial synchronization of cells was achieved by a technique combining phosphate starvation and a transient treatment with the DNA replication inhibitor aphidicolin. Six cDNAs corresponding to genes highly induced in proliferating cells and showing cell-cycle-regulated expression were obtained by the mRNA differential display technique. Full-length cDNA clones (cH2BAt and cH2AvAt) corresponding to two of the display products were subsequently isolated. The cH2BAt clone codes for a novel histone H2B protein, whereas the cH2AvAt cDNA corresponds to a gene encoding a new member of the highly conserved histone H2A.F/Z subfamily of chromosomal proteins. Further studies indicated that H2AvAt mRNA expression is tightly correlated with cell proliferation in cell-suspension cultures, and that closely related analogs of the encoded protein exist in Arabidopsis. The implications of the conservation of histone H2A.F/Z variants in plants are discussed.
Characterization of a Gene for Spinach CAP160 and Expression of Two Spinach Cold-Acclimation Proteins in Tobacco1
Authors: Kaye Claudia , Neven Lisa , Hofig Andrea , Li Qin-Bao , Haskell Dale , Guy Charles 
Published: July 2002

Abstract
The cDNA sequence for CAP160, an acidic protein previously linked with cold acclimation in spinach (Spinacia oleracea L.), was characterized and found to encode a novel acidic protein of 780 amino acids having very limited homology to a pair of Arabidopsis thaliana stress-regulated proteins, rd29A and rd29B. The lack of similarity in the structural organization of the spinach and Arabidopsis genes highlights the absence of a high degree of conservation of this cold-stress gene across taxonomic boundaries. The protein has several unique motifs that may relate to its function during cold stress. Expression of the CAP160 mRNA was increased by low-temperature exposure and water stress in a manner consistent with a probable function during stresses that involve dehydration. The coding sequences for CAP160 and CAP85, another spinach cold-stress protein, were introduced into tobacco (Nicotiana tabacum) under the control of the 35S promoter using Agrobacterium tumefaciens-based transformation. Tobacco plants expressing the proteins individually or coexpressing both proteins were evaluated for relative freezing-stress tolerance. The killing temperature for 50% of the cells of the transgenic plants was not different from that of the wild-type plants. As determined by a more sensitive time/temperature kinetic study, plants expressing the spinach proteins had slightly lower levels of electrolyte leakage than wild-type plants, indicative of a small reduction of freezing-stress injury. Clearly, the heterologous expression of two cold-stress proteins had no profound influence on stress tolerance, a result that is consistent with the quantitative nature of cold-stress-tolerance traits.
Root Growth and Oxygen Relations at Low Water Potentials. Impact of Oxygen Availability in Polyethylene Glycol Solutions1
Authors: Verslues Paul E. , Ober Eric S. , Sharp Robert E. 
Published: July 2002

AbstractPolyethylene glycol (PEG), which is often used to impose low water potentials (ψw) in solution culture, decreases O2 movement by increasing solution viscosity. We investigated whether this property causes O2 deficiency that affects the elongation or metabolism of maize (Zea mays L.) primary roots. Seedlings grown in vigorously aerated PEG solutions at ambient solution O2partial pressure (pO2) had decreased steady-state root elongation rates, increased root-tip alanine concentrations, and decreased root-tip proline concentrations relative to seedlings grown in PEG solutions of above-ambientpO2 (alanine and proline accumulation are responses to hypoxia and low ψw, respectively). Measurements of root pO2 were made using an O2 microsensor to ensure that increased solutionpO2 did not increase rootpO2 above physiological levels. In oxygenated PEG solutions that gave maximal root elongation rates, rootpO2 was similar to or less than (depending on depth in the tissue) pO2 of roots growing in vermiculite at the same ψw. Even without PEG, high solution pO2 was necessary to raise rootpO2 to the levels found in vermiculite-grown roots. Vermiculite was used for comparison because it has large air spaces that allow free movement of O2 to the root surface. The results show that supplemental oxygenation is required to avoid hypoxia in PEG solutions. Also, the data suggest that the O2 demand of the root elongation zone may be greater at low relative to high ψw, compounding the effect of PEG on O2 supply. Under O2-sufficient conditions root elongation was substantially less sensitive to the low ψwimposed by PEG than that imposed by dry vermiculite.
Adaptation of Active Proton Pumping and Plasmalemma ATPase Activity of Corn Roots to Low Root Medium pH1
Authors: Yan Feng , Feuerle Robert , Schäffer Stefanie , Fortmeier Helge , Schubert Sven 
Published: July 2002

Abstract
Corn (Zea mays L.) root adaptation to pH 3.5 in comparison with pH 6.0 (control) was investigated in long-term nutrient solution experiments. When pH was gradually reduced, comparable root growth was observed irrespective of whether the pH was 3.5 or 6.0. After low-pH adaptation, H+ release of corn roots in vivo at pH 5.6 was about 3 times higher than that of control. Plasmalemma of corn roots was isolated for investigation in vitro. At optimum assay pH, in comparison with control, the following increases of the various parameters were caused by low-pH treatment: (a) hydrolytic ATPase activity, (b) maximum initial velocity and Michaelis constant (c) activation energy of H+-ATPase, (d) H+-pumping activity, (e) H+ permeability of plasmalemma, and (f) pH gradient across the membranes of plasmalemma vesicles. In addition, vanadate sensitivity remained unchanged. It is concluded that plasmalemma H+-ATPase contributes significantly to the adaptation of corn roots to low pH. A restricted net H+release at low pH in vivo may be attributed to the steeper pH gradient and enhanced H+ permeability of plasmalemma but not to deactivation of H+-ATPase. Possible mechanisms responsible for adaptation of plasmalemma H+-ATPase to low solution pH during plant cultivation are discussed.