bluuebunny/crossref_metadata_2025_split huggingface dataset:
The impact of eastern Australian cut‐off lows on coastal sea levels
Authors: McInnes Kathleen L , Hubbert Graeme D 
Published: July 2002

AbstractCut‐off lows that develop off the east coast of Australia are a major cause of elevated coastal sea levels in this region. Their duration often exceeds a day and the combination of elevated sea levels with the high rainfall that commonly accompanies these events means that coastal flooding can be a major hazard. The processes contributing to higher‐than‐normal sea levels are a combination of storm surge and breaking wave setup. Three events are modelled using an atmospheric model, storm surge model and wave setup model. The storm surges resulting from the depressions are found to explain between one‐third and one‐half of the measured sea‐level residuals at the coast and are shown to develop in a regime of coast‐parallel winds that produce onshore Ekman transport. The timing of the storm surges are well captured in two of the events in which the atmospheric depressions are of broad spatial scale and well simulated by the atmospheric model. However, a poor simulation by the atmospheric model of the location of the third low, which is of smaller spatial scale, results in an inaccurate timing of the onset of the surge. The wave setup model produces sea levels at the coast that are around 11% of the incident rms wave heights. The total modelled sea‐level residual, obtained by adding the modelled wave setup to the storm surge, is qualitatively similar to the measured sea‐level residual. However, the modelled values are higher, especially at Sydney where the tide gauge is situated in a sheltered harbour location. In such sheltered locations, it is expected that some attenuation of the wave setup would occur and suggests that sea levels on the open coast could be considerably higher during such events. Copyright © 2001 Royal Meteorological Society
One‐dimensional site‐specific forecasting of radiation fog. Part I: Model formulation and idealised sensitivity studies
Authors: Clark P A , Hopwood W P 
Published: July 2002

AbstractThe Met. Office currently operates a high resolution mesoscale model that provides guidance on the likely formation of radiation fog on the spatial scale of 30–40 km. A project has been under way to build a Site‐Specific Forecast Model (SSFM) using a one‐dimensional version of the Met. Office Unified Model as a basis, with suitable modifications to its surface treatment driven by output from three‐dimensional NWP models. The SSFM has been applied to the forecasting of radiation fog as part of the European Commission sponsored project 4MIDaBLE (4Dimensional Met. Information DataBase Linked across Europe). The first part of this paper describes the model formulation and discusses its behaviour simulating radiation fog in idealised cases and its sensitivity to geostrophic wind speed and initial humidity. In addition to the expected sensitivity to wind and humidity, it has been found that the treatment of surface exchange processes can have a small but significant impact on the formation of fog, its formation and clearance times and its depth. Copyright © 2001 Royal Meteorological Society
A latent heat nudging scheme for the assimilation of precipitation data into an operational mesoscale model
Authors: Jones C D , Macpherson B 
Published: July 2002

AbstractSurface precipitation‐rate estimates derived from radar data are potentially of considerable value to high‐resolution Numerical Weather Prediction (NWP) models. This paper describes a scheme developed to assimilate precipitation rates derived from the UK weather radar network into the UK Met. Office Mesoscale Model, with the aim of improving the analysis and forecast of precipitation. It is based on ‘latent heat nudging’, in which the model profiles of latent heating are scaled by the ratio of observed and model precipitation rates. This causes the model to adjust so that the diagnosed precipitation rate agrees more closely with observations.The assimilation algorithm is outlined, and the results of a trial of the scheme are described. The scheme brings an increase in forecast skill for precipitation distribution in the first six to nine hours of the forecast, a conclusion supported both by objective verification against radar data and subjective assessment of 14 forecasts. The main benefit was found to occur in frontal cases. The scheme was implemented operationally on 16 April 1996. Copyright © 1997 Royal Meteorological Society
An assessment of annual mortality rates in adult‐sized migrant houbara bustards (Chlamydotis [undulata] macqueenii)
Authors: Combreau Olivier , Launay Frédéric , Lawrence Mark 
Published: July 2002

AbstractBetween the years 1994 and 2000, we assessed the mortality rate of adult‐sized, migrant Asian houbara bustards (Chlamydotis [undulata] macqueenii) via banding and satellite tracking programmes. The birds were captured either on their breeding grounds in Kazakhstan (Taukum desert and Buzachi peninsula) and in China (Jungar basin) or on their wintering grounds in Pakistan (Cholistan desert) and in the United Arab Emirates (Baynunah area). For the banding programme, 104 houbara bustards were marked and statistical analysis was performed on the number of transmitters and rings returned by falconers. This allowed us to calculate a 0.045 (SD 0.061) annual mortality rate attributable to hunting activities. The tracking programme analysed the fate of 41 houbara bustards equipped with satellite transmitters (PTTs). Overall, the satellite‐tracked birds were followed for 10,965 days and had travelled all over the distribution range of the species in Asia. The causes of mortality were assessed from the interpretation of the ARGOS data relayed by the sensors embarked on the PTTs. The annual mortality rate was derived from the calculation of the average finite daily survival rate using the Trent & Rongstad (1974) method. With this method, the overall annual mortality rate in adult‐sized houbara bustards migrating through Asia was 0.283 (95%lcl 0.186‐95%ucl 0.404). The hunting and poaching pressure could explain 73.5% of the observed mortality. The mortality rate during winter, when the houbara is under severe hunting pressure, was 11.2 times higher than during the breeding season. Houbara appear to be especially at risk in Pakistan, Afghanistan and Iran. A VORTEX simulation showed that under current hunting and poaching pressures, the probability of extinction of the houbara population modelled can be anticipated at 50 years with a 94% probability. The maximum sustainable yield was estimated at 7.2% of the adult‐sized population whereas as much as 20.8% is currently taken. This work stresses the need for conservationists and Arab falconers to take appropriate concerted measures as soon as possible.
Chromosome Evolution: The Junction of Mammalian Chromosomes in the Formation of Mouse Chromosome 10
Authors: Pletcher Mathew T. , Roe Bruce A. , Chen Fang , Do Trang , Do Ahn , Malaj Eda , Reeves Roger H. 
Published: July 2002

During evolution, chromosomes are rearranged and become fixed into new patterns in new species. The relatively conservative nature of this process supports predictions of the arrangement of ancestral mammalian chromosomes, but the basis for these rearrangements is unknown. Physical mapping of mouse chromosome 10 (MMU 10) previously identified a 380-kb region containing the junction of material represented in human on chromosomes 21 (HSA 21) and 22 (HSA 22) that occurred in the evolutionary lineage of the mouse. Here, acquisition of 275 kb of mouse genomic sequence from this region and comparative sequence analysis with HSA 21 and HSA 22 narrowed the junction from 380 kb to 18 kb. The minimal junction region on MMU 10 contains a variety of repeats, including an L32-like ribosomal element and low-copy sequences found on several mouse chromosomes and represented in the mouse EST database. Sequence level analysis of an interchromosomal rearrangement during evolution has not been reported previously.[The sequence data described in this paper have been submitted to the GenBank data library under accession nos. AC006507, AC005818, AC005302, AP000215–AP000218,D87009, and AL008723.]
Molecular Characterization of Two Natural Hotspots in the Drosophila buzzatii Genome Induced by Transposon Insertions
Authors: Cáceres Mario , Puig Marta , Ruiz Alfredo 
Published: July 2002

Transposable elements (TEs) have been implicated in the generation of genetic rearrangements, but their potential to mediate changes in the organization and architecture of host genomes could be even greater than previously thought. Here, we describe the naturally occurring structural and nucleotide variation around two TE insertions in the genome of Drosophila buzzatii. The studied regions correspond to the breakpoints of a widespread chromosomal inversion generated by ectopic recombination between oppositely oriented copies of a TE namedGalileo. A detailed molecular analysis by Southern hybridization, PCR amplification, and DNA sequencing of 7.1 kb surrounding the inversion breakpoints in 39 D. buzzatii lines revealed an unprecedented degree of restructuring, consisting of 22 insertions of ten previously undescribed TEs, 13 deletions, 1 duplication, and 1 small inversion. All of these alterations occurred exclusively in inverted chromosomes and appear to have accumulated after the insertion of the Galileo elements, within or close to them. The nucleotide variation at the studied regions is six times lower in inverted than in noninverted chromosomes, suggesting that most of the observed changes originated in only 84,000 years.Galileo elements thus seemed to promote the transformation of these, otherwise normal, chromosomal regions in genetically unstable hotspots and highly efficient traps for transposon insertions. The particular features of two new Galileo copies found indicate that this TE belongs to the Foldback family. Together, our results strengthen the importance of TEs, and especially DNA transposons, as inducers of genome plasticity in evolution.[The sequence data described in this paper have been submitted to the GenBank data library under accession nos.AF368842–AF368859 and AF368861–AF368900. In addition, sequences submitted under accession nos. AF162796–AF162799 were used as a basis for this study.]
Cinnamate-4-Hydroxylase Expression in Arabidopsis (Regulation in Response to Development and the Environment)
Authors: Bell-Lelong D. A. , Cusumano J. C. , Meyer K. , Chapple C. 
Published: July 2002

Abstract
Cinnamate-4-hydroxylase (C4H) is the first Cyt P450-dependent monooxygenase of the phenylpropanoid pathway. To study the expression of this gene in Arabidopsis thaliana, a C4H cDNA clone from the Arabidopsis expressed sequence tag database was identified and used to isolate its corresponding genomic clone. The entire C4H coding sequence plus 2.9 kb of its promoter were isolated on a 5.4-kb HindIII fragment of this cosmid. Inspection of the promoter sequence revealed the presence of a number of putative regulatory motifs previously identified in the promoters of other phenylpropanoid pathway genes. The expression of C4H was analyzed by RNA blot hybridization analysis and in transgenic Arabidopsis carrying a C4H-β-glucuronidase transcriptional fusion. C4H message accumulation was light-dependent, but was detectable even in dark-grown seedlings. Consistent with these data, C4H mRNA was accumulated to light-grown levels in etiolated det1–1 mutant seedlings. C4H is widely expressed in various Arabidopsis tissues, particularly in roots and cells undergoing lignification. The C4H-driven β-glucuronidase expression accurately reflected the tissue-specificity and wound-inducibility of the C4H promoter indicated by RNA blot hybridization analysis. A modest increase in C4H expression was observed in the tt8 mutant of Arabidopsis.
Structure and Blue-Light-Responsive Transcription of a Chloroplast psbD Promoter from Arabidopsis thaliana
Authors: Hoffer P. H. , Christopher D. A. 
Published: July 2002

Abstract
We characterized the effects of light on psbD transcription and mRNA levels during chloroplast development in Arabidopsis thaliana. After 6 to 12 hours of illumination of dark-grown seedlings, two psbD mRNAs were detected and their 5[prime] ends were mapped to positions -550 and -190 bp upstream from the psbD translational start codon. Their kinetics of accumulation resembled the accumulation of chloroplast psbA and rbcL mRNAs but differed from the accumulation of the nuclear-encoded Lhcb and Chs mRNAs. A third psbD mRNA with its 5[prime] end at position -950 accumulated after illumination of &gt; 180 h. The 5[prime] ends of this transcript were mapped to a nucleotide sequence that is highly conserved with functional sequences in the barley (Hordeum vulgare) blue-light-responsive promoter (BLRP). Transcription from the Arabidopsis psbD promoter was 3-fold higher in blue relative to red light, whereas red and blue light affected total chloroplast, rbcL, and 16S rDNA transcription similarly. This study shows that transcription of Arabidopsis psbD is mediated by a BLRP and suggests that psbD genes in other land plants are regulated by a common blue-light-signaling pathway. Isolating the BLRP from Arabidopsis will allow molecular genetic studies aimed at identifying the pertinent photoreceptor and components of this phototransduction pathway.
Identification of Promoter Elements Involved in the Cytosolic Ca2+-Mediated Photoregulation of Maize cab-m1 Expression
Authors: Shiina T. , Nishii A. , Toyoshima Y. , Bogorad L. 
Published: July 2002

Abstract
Changes in cytoplasmic Ca2+ levels are involved in the regulation of several plant genes. However, to our knowledge, no regions of genes or specific cis elements have been shown to be involved in the regulation of plant gene expression by cytosolic Ca2+ signaling. The maize (Zea mays) gene cab-m1, which encodes a light-harvesting chlorophyll a/b-binding apoprotein, is positively photoregulated in mesophyll cells (MC) but not in bundle-sheath cells (BSC). This gene is highly preferentially expressed in maize MC versus BSC. In situ transient expression assays have revealed that exposure of tissues to ethyleneglycol-bis(β-aminoethyl ether)-N,N[prime]-tetraacetic acid (EGTA), which chelates Ca2+, blocks the photostimulation of cab-m1 full promoter (-1026 to +14) activity in MC of leaf segments of dark-grown maize seedlings. EGTA has no effect on expression in BSC. These results suggest that light-induced elevation of the cytosolic Ca2+ concentration in MC is required for the enhancement of cab-m1 expression in MC. Deletion of the sequence from -1026 to -360 completely abolished Ca2+ responsiveness of cab-m1 expression in MC. On the other hand, a 54-bp fragment in the 5[prime] flanking region (-953 to -899 relative to the translation start site) conferred Ca2+ responsiveness on a -359 core promoter:reporter gene, suggesting that Ca2+ signaling is mediated via specific sequences in this short fragment. Furthermore, possible involvement of Ca2+-calmodulin in the signal transduction chain for regulating cab-m1 expression was suggested by the results of inhibitor experiments.
Chlorophyll Breakdown in Senescent Chloroplasts (Cleavage of Pheophorbide a in Two Enzymic Steps)
Authors: Rodoni S. , Muhlecker W. , Anderl M. , Krautler B. , Moser D. , Thomas H. , Matile P. , Hortensteiner S. 
Published: July 2002

Abstract
The cleavage of pheophorbide (Pheide) a into primary fluoescent chlorophyll (Chl) catabolites (pFCCs) in senescent chloroplasts was investigated. Chloroplast preparations isolated from senescent canola (Brassica napus) cotyledons exhibited light-dependent production of pFCC when assay mixtures were supplemented with ferredoxin (Fd). pFCC production in detergent-solubilized membranes was dependent on the presence of an Fd-reducing system. Pheide a cleavage required the action of two proteins, Pheide a oxygenase and a stroma protein. In the absence of stroma protein, Pheide a oxygenase converted Pheide a into a red Chl catabolite (RCC), the presumptive intermediary product of Pheide a cleavage. Incubation of the stroma protein (RCC reductase) together with chemically synthesized RCC resulted in the production of three different FCCs. Two of these catabolites were identical to the pFCCs from canola or barley (Hordeum vulgare) (pFCC-1) and sweet pepper (Capsicum annuum) (pFCC-2), respectively. Thus, the conversion of Pheide a to pFCC could be demonstrated to proceed in two consecutive steps, and both reactions depended on reduced Fd as the source of electrons. The function of Fd in Chl breakdown in vivo is corroborated by the marked retention of this protein until the late stages of senescence, as demonstrated by immunoblotting.
Salinity Promotes Accumulation of 3-Dimethylsulfoniopropionate and Its Precursor S-Methylmethionine in Chloroplasts1
Authors: Trossat Claudine , Rathinasabapathi Bala , Weretilnyk Elizabeth A. , Shen Tun-Li , Huang Zhi-Heng , Gage Douglas A. , Hanson Andrew D. 
Published: July 2002

Abstract
Wollastonia biflora (L.) DC. plants accumulate the osmoprotectant 3-dimethylsulfoniopropionate (DMSP), particularly when salinized. DMSP is known to be synthesized in the chloroplast fromS-methylmethionine (SMM) imported from the cytosol, but the sizes of the chloroplastic and extrachloroplastic pools of these compounds are unknown. We therefore determined DMSP and SMM in mesophyll protoplasts and chloroplasts. Salinization with 30% (v/v) artificial seawater increased protoplast DMSP levels from 4.6 to 6.0 μmol mg−1 chlorophyll (Chl), and chloroplast levels from 0.9 to 1.9 μmol mg−1 Chl. The latter are minimum values because intact chloroplasts leaked DMSP during isolation. Correcting for this leakage, it was estimated that in vivo about one-half of the DMSP is chloroplastic and that stromal DMSP concentrations in control and salinized plants are about 60 and 130 mm, respectively. Such concentrations would contribute significantly to chloroplast osmoregulation and could protect photosynthetic processes from stress injury. SMM levels were measured using a novel mass-spectrometric method. About 40% of the SMM was located in the chloroplast in unsalinized W. biflora plants, as was about 80% in salinized plants; the chloroplastic pool in both cases was approximately 0.1 μmol mg−1 Chl. In contrast, ≥85% of the SMM was extrachloroplastic in pea (Pisum sativum L.) and spinach (Spinacia oleracea L.), which lack DMSP. DMSP synthesis may be associated with enhanced accumulation of SMM in the chloroplast.
Two Isoforms of NADPH:Cytochrome P450 Reductase inArabidopsis thaliana
Authors: Mizutani Masaharu , Ohta Daisaku 
Published: July 2002

Abstract
We have investigated two NADPH-cytochrome (Cyt) P450 reductase isoforms encoded by separate genes (AR1 and AR2) in Arabidopsis thaliana. We isolated AR1 and AR2 cDNAs using a mung bean (Phaseolus aureus L.) NADPH-Cyt P450 reductase cDNA as a probe. The recombinant AR1 and AR2 proteins produced using a baculovirus expression system showed similarKm values for Cyt c and NADPH, respectively. In the reconstitution system with a recombinant cinnamate 4-hydroxylase (CYP73A5), the recombinant AR1 and AR2 proteins gave the same level of cinnamate 4-hydroxylase activity (about 70 nmol min−1 nmol−1 P450). The AR2gene expression was transiently induced by 4- and 3-fold within 1 h of wounding and light treatments, respectively, and the induction time course preceded those of CYP73A5 and a phenylalanine ammonia-lyase (PAL1) gene. On the contrary, the AR1 expression level did not change during the treatments. Analysis of the AR1 andAR2 gene structure revealed that only theAR2 promoter contained three putative sequence motifs (boxes P, A, and L), which are involved in the coordinated expression of CYP73A5 and other phenylpropanoid pathway genes. These results suggest the possibility that AR2transcription may be functionally linked to the induced levels of phenylpropanoid pathway enzymes.
Expression of an Arabidopsis Aspartate Kinase/Homoserine Dehydrogenase Gene Is Metabolically Regulated by Photosynthesis-Related Signals but Not by Nitrogenous Compounds1
Authors: Zhu-Shimoni Judith X. , Galili Gad 
Published: July 2002

Abstract
Although the control of carbon fixation and nitrogen assimilation has been studied in detail, relatively little is known about the regulation of carbon and nitrogen flow into amino acids. In this paper we report our study of the metabolic regulation of expression of an Arabidopsis aspartate kinase/homoserine dehydrogenase (AK/HSD) gene, which encodes two linked key enzymes in the biosynthetic pathway of aspartate family amino acids. Northern blot analyses, as well as expression of chimeric AK/HSD-β-glucuronidase constructs, have shown that the expression of this gene is regulated by the photosynthesis-related metabolites sucrose and phosphate but not by nitrogenous compounds. In addition, analysis of AK/HSD promoter deletions suggested that a CTTGACTCTA sequence, resembling the binding site for the yeast GCN4 transcription factor, is likely to play a functional role in the expression of this gene. Nevertheless, longer promoter fragments, lacking the GCN4-like element, were still able to confer sugar inducibility, implying that the metabolic regulation of this gene is apparently obtained by multiple and redundant promoter sequences. The present and previous studies suggest that the conversion of aspartate into either the storage amino acid asparagine or aspartate family amino acids is subject to a coordinated, reciprocal metabolic control, and this biochemical branch point is a part of a larger, coordinated regulatory mechanism of nitrogen and carbon storage and utilization.
Initial Steps in the Assembly of the Vacuole-Type H+-ATPase1
Authors: Frey Richard K. , Randall Stephen K. 
Published: July 2002

Abstract
The plant vacuole is acidified by a complex multimeric enzyme, the vacuole-type H+-ATPase (V-ATPase). The initial association of ATPase subunits on membranes was studied using an in vitro assembly assay. The V-ATPase assembled onto microsomes when V-ATPase subunits were supplied. However, when the A or B subunit or the proteolipid were supplied individually, only the proteolipid associated with membranes. By using poly(A+) RNA depleted in the B subunit and proteolipid subunit mRNA, we demonstrated A subunit association with membranes at substoichiometric amounts of the B subunit or the 16-kD proteolipid. These data suggest that poly(A+) RNA-encoded proteins are required to catalyze the A subunit membrane assembly. Initial events were further studied by in vivo protein labeling. Consistent with a temporal ordering of V-ATPase assembly, membranes contained only the A subunit at early times; at later times both the A and B subunits were found on the membranes. A large-mass ATPase complex was not efficiently formed in the absence of membranes. Together, these data support a model whereby the A subunit is first assembled onto the membrane, followed by the B subunit.