bluuebunny/crossref_metadata_2025 huggingface dataset:
RNA Expression Profiles and Data Mining of Sugarcane Response to Low Temperature
Authors: Nogueira Fábio T.S. , De Rosa Vicente E. , Menossi Marcelo , Ulian Eugênio C. , Arruda Paulo
Published: August 2003

Tropical and subtropical plants are generally sensitive to cold and can show appreciable variation in their response to cold stress when exposed to low positive temperatures. Using nylon filter arrays, we analyzed the expression profile of 1,536 expressed sequence tags (ESTs) of sugarcane (Saccharum sp. cv SP80-3280) exposed to cold for 3 to 48 h. Thirty-four cold-inducible ESTs were identified, of which 20 were novel cold-responsive genes that had not previously been reported as being cold inducible, including cellulose synthase, ABI3-interacting protein 2, a negative transcription regulator, phosphate transporter, and others, as well as several unknown genes. In addition, 25 ESTs were identified as being down-regulated during cold exposure. Using a database of cold-regulated proteins reported for other plants, we searched for homologs in the sugarcane EST project database (SUCEST), which contains 263,000 ESTs. Thirty-three homologous putative cold-regulated proteins were identified in the SUCEST database. On the basis of the expression profiles of the cold-inducible genes and the data-mining results, we propose a molecular model for the sugarcane response to low temperature.
Subcellular Targeting of Nine Calcium-Dependent Protein Kinase Isoforms from Arabidopsis
Authors: Dammann Christian , Ichida Audrey , Hong Bimei , Romanowsky Shawn M. , Hrabak Estelle M. , Harmon Alice C. , Pickard Barbara G. , Harper Jeffrey F.
Published: August 2003

Calcium-dependent protein kinases (CDPKs) are specific to plants and some protists. Their activation by calcium makes them important switches for the transduction of intracellular calcium signals. Here, we identify the subcellular targeting potentials for nine CDPK isoforms from Arabidopsis, as determined by expression of green fluorescent protein (GFP) fusions in transgenic plants. Subcellular locations were determined by fluorescence microscopy in cells near the root tip. Isoforms AtCPK3-GFP and AtCPK4-GFP showed a nuclear and cytosolic distribution similar to that of free GFP. Membrane fractionation experiments confirmed that these isoforms were primarily soluble. A membrane association was observed for AtCPKs 1, 7, 8, 9, 16, 21, and 28, based on imaging and membrane fractionation experiments. This correlates with the presence of potential N-terminal acylation sites, consistent with acylation as an important factor in membrane association. All but one of the membrane-associated isoforms targeted exclusively to the plasma membrane. The exception was AtCPK1-GFP, which targeted to peroxisomes, as determined by covisualization with a peroxisome marker. Peroxisome targeting of AtCPK1-GFP was disrupted by a deletion of two potential N-terminal acylation sites. The observation of a peroxisome-located CDPK suggests a mechanism for calcium regulation of peroxisomal functions involved in oxidative stress and lipid metabolism.
The Arabidopsis NHL3 Gene Encodes a Plasma Membrane Protein and Its Overexpression Correlates with Increased Resistance to Pseudomonas syringae pv. tomato DC3000
Authors: Varet Anne , Hause Bettina , Hause Gerd , Scheel Dierk , Lee Justin
Published: August 2003

The Arabidopsis genome contains a family of NDR1/HIN1-like (NHL) genes that show homology to the nonrace-specific disease resistance (NDR1) and the tobacco (Nicotiana tabacum) harpin-induced (HIN1) genes. NHL3 is a pathogen-responsive member of this NHL gene family that is potentially involved in defense. In independent transgenic NHL3-overexpressing plant lines, a clear correlation between increased resistance to virulent Pseudomonas syringae pv. tomato DC3000 and enhanced NHL3 transcript levels was seen. These transgenic plants did not show enhanced pathogenesis-related gene expression or reactive oxygen species accumulation. Biochemical and localization experiments were performed to assist elucidation of how NHL3 may confer enhanced disease resistance. Gene constructs expressing amino-terminal c-myc-tagged or carboxyl-terminal hemagglutinin epitope (HA)-tagged NHL3 demonstrated membrane localization in transiently transformed tobacco leaves. Stable Arabidopsis transformants containing the NHL3-HA construct corroborated the findings observed in tobacco. The detected immunoreactive proteins were 10 kD larger than the calculated size and could be partially accounted for by the glycosylation state. However, the expected size was not attained with deglycosylation, suggesting possibly additional posttranslational modification. Detergent treatment, but not chemicals used to strip membrane-associated proteins, could displace the immunoreactive signal from microsomal fractions, showing that NHL3 is tightly membrane associated. Furthermore, immunofluorescence and immunogold labeling, coupled with two-phase partitioning techniques, revealed plasma membrane localization of NHL3-HA. This subcellular localization of NHL3 positions it at an initial contact site to pathogens and may be important in facilitating interception of pathogen-derived signals.
Expression of 1L-Myoinositol-1-Phosphate Synthase in Organelles
Authors: Lackey Kimberly Helms , Pope Patricia Marie , Johnson Margaret Dean
Published: August 2003

We have studied the expression of 1l-myoinositol-1-phosphate synthase (MIPS; EC 5.5.1.4) in developing organs of Phaseolus vulgaris to define genetic controls that spatially regulate inositol phosphate biosynthesis. MIPS, the pivotal biosynthetic enzyme in inositol metabolism, is the only enzyme known to catalyze the conversion of glucose 6-phosphate to inositol phosphate. It is found in unicellular and multicellular eukaryotes and has been isolated as a soluble enzyme from both. Thus, it is widely accepted that inositol phosphate biosynthesis is largely restricted to the cytosol. Here, we report findings that suggest the enzyme is also expressed in membrane-bound organelles. Microscopic and biochemical analyses detected MIPS expression in plasma membranes, plastids, mitochondria, endoplasmic reticula, nuclei, and cell walls of bean. To address mechanisms by which the enzyme could be targeted to or through membranes, MIPS genes were analyzed for sorting signals within primary structures and upstream open reading frames that we discovered through our sequence analyses. Comprehensive computer analyses revealed putative transit peptides that are predicted to target the enzyme to different cellular compartments. Reverse transcriptase PCR experiments suggest that these putative targeting peptides are expressed in bean roots and leaves.
C-Terminal KDEL Sequence of A KDEL-Tailed Cysteine Proteinase (Sulfhydryl-Endopeptidase) Is Involved in Formation of KDEL Vesicle and in Efficient Vacuolar Transport of Sulfhydryl-Endopeptidase
Authors: Okamoto Takashi , Shimada Tomoo , Hara-Nishimura Ikuko , Nishimura Mikio , Minamikawa Takao
Published: August 2003

Sulfhydryl-endopeptidase (SH-EP) is a papain-type vacuolar proteinase expressed in cotyledons of germinated Vigna mungo seeds, and the enzyme possesses a C-terminal propeptide containing KDEL tail, an endoplasmic reticulum retention signal for soluble proteins. SH-EP is transported to vacuoles via a KDEL vesicle (KV) through a Golgi complex-independent route. To see the function of the KDEL sequence of SH-EP, wild-type SH-EP and its KDEL deletion mutant (SH-EPΔKDEL) were heterologously expressed in Arabidopsis and in cultured tobacco Bright Yellow 2 cells, and their intracellular transport pathways and localizations were analyzed. A combination of the results from analyses for transformed Arabidopsis and tobacco (Nicotiana tabacum) cells indicated that wild-type SH-EP is packed into KV-like vesicles through the KDEL sequence and is transported to vacuoles in the cells of transformants. In contrast, KV was not formed/induced in the cells expressing SH-EPΔKDEL, and the mutant protein was mainly secreted. Therefore, the C-terminal KDEL sequence of the KDEL-tailed cysteine proteinase is thought to be involved in the formation of KV, and in the efficient vacuolar transport of the proteins through KV.
Systematic Trans-Genomic Comparison of Protein Kinases between Arabidopsis and Saccharomyces cerevisiae
Authors: Wang Degeng , Harper Jeffrey F. , Gribskov Michael
Published: August 2003

The genome of the budding yeast (Saccharomyces cerevisiae) provides an important paradigm for transgenomic comparisons with other eukaryotic species. Here, we report a systematic comparison of the protein kinases of yeast (119 kinases) and a reference plant Arabidopsis (1,019 kinases). Using a whole-protein-based, hierarchical clustering approach, the complete set of protein kinases from both species were clustered. We validated our clustering by three observations: (a) clustering pattern of functional orthologs proven in genetic complementation experiments, (b) consistency with reported classifications of yeast kinases, and (c) consistency with the biochemical properties of those Arabidopsis kinases already experimentally characterized. The clustering pattern identified no overlap between yeast kinases and the receptor-like kinases (RLKs) of Arabidopsis. Ten more kinase families were found to be specific for one of the two species. Among them, the calcium-dependent protein kinase and phosphoenolpyruvate carboxylase kinase families are specific for plants, whereas the Ca2+/calmodulin-dependent protein kinase and provirus insertion in mouse-like kinase families were found only in yeast and animals. Three yeast kinase families, nitrogen permease reactivator/halotolerance-5), polyamine transport kinase, and negative regulator of sexual conjugation and meiosis, are absent in both plants and animals. The majority of yeast kinase families (21 of 26) display Arabidopsis counterparts, and all are mapped into Arabidopsis families of intracellular kinases that are not related to RLKs. Representatives from 11 of the common families (54 kinases from Arabidopsis and 17 from yeast) share an extremely high degree of similarity (blast E value < 10-80), suggesting the likelihood of orthologous functions. Selective expansion of yeast kinase families was observed in Arabidopsis. This is most evident for yeast genes CBK1, HRR25, and SNF1 and the kinase family S6K. Reduction of kinase families was also observed, as in the case of the NEK-like family. The distinguishing features between the two sets of kinases are the selective expansion of yeast families and the generation of a limited number of new kinase families for new functionality in Arabidopsis, most notably, the Arabidopsis RLKs that constitute important components of plant intercellular communication apparatus.
Nod Factor-Induced Root Hair Curling: Continuous Polar Growth towards the Point of Nod Factor Application
Authors: Esseling John J. , Lhuissier Franck G.P. , Emons Anne Mie C.
Published: August 2003

A critical step in establishing a successful nitrogen-fixing symbiosis between rhizobia and legume plants is the entrapment of the bacteria between root hair cell walls, usually in characteristic 180° to 360° curls, shepherd's crooks, which are formed by the host's root hairs. Purified bacterial signal molecules, the nodulation factors (NFs), which are lipochitooligosaccharides, induce root hair deformation in the appropriate host legume and have been proposed to be a key player in eliciting root hair curling. However, for curling to occur, the presence of intact bacteria is thought to be essential. Here, we show that, when spot applied to one side of the growing Medicago truncatula root hair tip, purified NF alone is sufficient to induce reorientation of the root hair growth direction, or a full curl. Using wild-type M. truncatula containing the pMtENOD11::GUS construct, we demonstrate that MtENOD11::GUS is expressed after spot application. The data have been incorporated into a cell biological model, which explains the formation of shepherd's crook curls around NF-secreting rhizobia by continuous tip growth reorientation.
MPB2C, a Microtubule-Associated Plant Protein Binds to and Interferes with Cell-to-Cell Transport of Tobacco Mosaic Virus Movement Protein
Authors: Kragler Friedrich , Curin Mirela , Trutnyeva Kateryna , Gansch Andreas , Waigmann Elisabeth
Published: August 2003

The movement protein of tobacco mosaic virus, MP30, mediates viral cell-to-cell transport via plasmodesmata. The complex MP30 intra- and intercellular distribution pattern includes localization to the endoplasmic reticulum, cytoplasmic bodies, microtubules, and plasmodesmata and likely requires interaction with plant endogenous factors. We have identified and analyzed an MP30-interacting protein, MPB2C, from the host plant Nicotiana tabacum. MPB2C constitutes a previously uncharacterized microtubule-associated protein that binds to and colocalizes with MP30 at microtubules. In vivo studies indicate that MPB2C mediates accumulation of MP30 at microtubules and interferes with MP30 cell-to-cell movement. In contrast, intercellular transport of a functionally enhanced MP30 mutant, which does not accumulate and colocalize with MP30 at microtubules, is not impaired by MPB2C. Together, these data support the concept that MPB2C is not required for MP30 cell-to-cell movement but may act as a negative effector of MP30 cell-to-cell transport activity.
Enhanced Formaldehyde Detoxification by Overexpression of Glutathione-Dependent Formaldehyde Dehydrogenase from Arabidopsis
Authors: Achkor Hakima , Díaz Maykelis , Fernández M. Rosario , Biosca Josep Antoni , Parés Xavier , Martínez M. Carmen
Published: August 2003

The ADH2 gene codes for the Arabidopsis glutathione-dependent formaldehyde dehydrogenase (FALDH), an enzyme involved in formaldehyde metabolism in eukaryotes. In the present work, we have investigated the potential role of FALDH in detoxification of exogenous formaldehyde. We have generated a yeast (Saccharomyces cerevisiae) mutant strain (sfa1Δ) by in vivo deletion of the SFA1 gene that codes for the endogenous FALDH. Overexpression of Arabidopsis FALDH in this mutant confers high resistance to formaldehyde added exogenously, which demonstrates the functional conservation of the enzyme through evolution and supports its essential role in formaldehyde metabolism. To investigate the role of the enzyme in plants, we have generated Arabidopsis transgenic lines with modified levels of FALDH. Plants overexpressing the enzyme show a 25% increase in their efficiency to take up exogenous formaldehyde, whereas plants with reduced levels of FALDH (due to either a cosuppression phenotype or to the expression of an antisense construct) show a marked slower rate and reduced ability for formaldehyde detoxification as compared with the wild-type Arabidopsis. These results show that the capacity to take up and detoxify high concentrations of formaldehyde is proportionally related to the FALDH activity in the plant, revealing the essential role of this enzyme in formaldehyde detoxification.
Fructans, But Not the Sucrosyl-Galactosides, Raffinose and Loliose, Are Affected by Drought Stress in Perennial Ryegrass
Authors: Amiard Véronique , Morvan-Bertrand Annette , Billard Jean-Pierre , Huault Claude , Keller Felix , Prud'homme Marie-Pascale
Published: August 2003

The aim of this study was to evaluate the putative role of the sucrosyl-galactosides, loliose [α-d-Gal (1,3) α-d-Glc (1,2) β-d-Fru] and raffinose [α-d-Gal (1,6) α-d-Glc (1,2) β-d-Fru], in drought tolerance of perennial ryegrass and to compare it with that of fructans. To that end, the loliose biosynthetic pathway was first established and shown to operate by a UDP-Gal: sucrose (Suc) 3-galactosyltransferase, tentatively termed loliose synthase. Drought stress increased neither the concentrations of loliose and raffinose nor the activities of loliose synthase and raffinose synthase (EC 2.4.1.82). Moreover, the concentrations of the raffinose precursors, myoinositol and galactinol, as well as the gene expressions of myoinositol 1-phosphate synthase (EC 5.5.1.4) and galactinol synthase (EC 2.4.1.123) were either decreased or unaffected by drought stress. Taken together, these data are not in favor of an obvious role of sucrosyl-galactosides in drought tolerance of perennial ryegrass at the vegetative stage. By contrast, drought stress caused fructans to accumulate in leaf tissues, mainly in leaf sheaths and elongating leaf bases. This increase was mainly due to the accumulation of long-chain fructans (degree of polymerization > 8) and was not accompanied by a Suc increase. Interestingly, Suc but not fructan concentrations greatly increased in drought-stressed roots. Putative roles of fructans and sucrosyl-galactosides are discussed in relation to the acquisition of stress tolerance.
PAUSED, a Putative Exportin-t, Acts Pleiotropically in Arabidopsis Development But Is Dispensable for Viability
Authors: Li Junjie , Chen Xuemei
Published: August 2003

Exportin-t was first identified in humans as a protein that mediates the export of tRNAs from the nucleus to the cytoplasm. Mutations in Los1p, the Saccharomyces cerevisiae exportin-t homolog, result in nuclear accumulation of tRNAs. Because no exportin-t mutants have been reported in multicellular organisms, the developmental functions of exportin-t have not been determined. Here, we report the isolation and characterization of two Arabidopsis exportin-t mutants, paused-5 and paused-6. The mutant phenotypes indicate that exportin-t acts pleiotropically in plant development. In particular, paused-5 and paused-6 result in delayed leaf formation during vegetative development. The two paused mutations also cause the transformation of reproductive organs into perianth organs in the hua1-1 hua2-1 background, which is partially defective in reproductive organ identity specification. The floral phenotypes of hua1-1 hua2-1 paused mutants resemble those of mutations in the floral homeotic gene AGAMOUS. Moreover, paused-5 enhances the mutant phenotypes of two floral meristem identity genes, LEAFY and APETALA1. The developmental defects caused by paused mutations confirm the important roles of exportin-t in gene expression in multicellular organisms. In addition, a paused null allele, paused-6, is still viable, suggesting the presence of redundant tRNA export pathway(s) in Arabidopsis.
Stomatal Closure during Leaf Dehydration, Correlation with Other Leaf Physiological Traits
Authors: Brodribb Tim J. , Holbrook N. Michele
Published: August 2003

The question as to what triggers stomatal closure during leaf desiccation remains controversial. This paper examines characteristics of the vascular and photosynthetic functions of the leaf to determine which responds most similarly to stomata during desiccation. Leaf hydraulic conductance (Kleaf) was measured from the relaxation kinetics of leaf water potential (Ψl), and a novel application of this technique allowed the response of Kleaf to Ψl to be determined. These “vulnerability curves” show that Kleaf is highly sensitive to Ψl and that the response of stomatal conductance to Ψl is closely correlated with the response of Kleaf to Ψl. The turgor loss point of leaves was also correlated with Kleaf and stomatal closure, whereas the decline in PSII quantum yield during leaf drying occurred at a lower Ψl than stomatal closure. These results indicate that stomatal closure is primarily coordinated with Kleaf. However, the close proximity of Ψl at initial stomatal closure and initial loss of Kleaf suggest that partial loss of Kleaf might occur regularly, presumably necessitating repair of embolisms.
Modulation of Citrate Metabolism Alters Aluminum Tolerance in Yeast and Transgenic Canola Overexpressing a Mitochondrial Citrate Synthase
Authors: Anoop Valar M. , Basu Urmila , McCammon Mark T. , McAlister-Henn Lee , Taylor Gregory J.
Published: August 2003

Aluminum (Al) toxicity is a major constraint for crop production in acid soils, although crop cultivars vary in their tolerance to Al. We have investigated the potential role of citrate in mediating Al tolerance in Al-sensitive yeast (Saccharomyces cerevisiae; MMYO11) and canola (Brassica napus cv Westar). Yeast disruption mutants defective in genes encoding tricarboxylic acid cycle enzymes, both upstream (citrate synthase [CS]) and downstream (aconitase [ACO] and isocitrate dehydrogenase [IDH]) of citrate, showed altered levels of Al tolerance. A triple mutant of CS (Δcit123) showed lower levels of citrate accumulation and reduced Al tolerance, whereas Δaco1- and Δidh12-deficient mutants showed higher accumulation of citrate and increased levels of Al tolerance. Overexpression of a mitochondrial CS (CIT1) in MMYO11 resulted in a 2- to 3-fold increase in citrate levels, and the transformants showed enhanced Al tolerance. A gene for Arabidopsis mitochondrial CS was overexpressed in canola using an Agrobacterium tumefaciens-mediated system. Increased levels of CS gene expression and enhanced CS activity were observed in transgenic lines compared with the wild type. Root growth experiments revealed that transgenic lines have enhanced levels of Al tolerance. The transgenic lines showed enhanced levels of cellular shoot citrate and a 2-fold increase in citrate exudation when exposed to 150 μm Al. Our work with yeast and transgenic canola clearly suggest that modulation of different enzymes involved in citrate synthesis and turnover (malate dehydrogenase, CS, ACO, and IDH) could be considered as potential targets of gene manipulation to understand the role of citrate metabolism in mediating Al tolerance.
Overproduction of Cytokinins in Petunia Flowers Transformed with PSAG12-IPT Delays Corolla Senescence and Decreases Sensitivity to Ethylene
Authors: Chang Hsiang , Jones Michelle L. , Banowetz Gary M. , Clark David G.
Published: August 2003

Plant senescence is regulated by a coordinated genetic program mediated in part by changes in ethylene, abscisic acid (ABA), and cytokinin content. Transgenic plants with delayed senescence are useful for studying interactions between these signaling mechanisms. Expression of ipt, a cytokinin biosynthetic gene from Agrobacterium tumefaciens, under the control of the promoter from a senescence-associated gene (SAG12) has been one approach used to delay senescence. We transformed petunia (Petunia x hybrida cv V26) with PSAG12-IPT. Two independently transformed lines with extended flower longevity (I-1-7-22 and I-3-18-34) were used to study the effects of elevated cytokinin content on ethylene synthesis and sensitivity and ABA accumulation in petunia corollas. Floral senescence in these lines was delayed 6 to 10 d relative to wild-type (WT) flowers. Ipt transcripts increased in abundance after pollination and were accompanied by increased cytokinin accumulation. Endogenous ethylene production was induced by pollination in both WT and IPT corollas, but this increase was delayed in IPT flowers. Flowers from IPT plants were less sensitive to exogenous ethylene and required longer treatment times to induce endogenous ethylene production, corolla senescence, and up-regulation of the senescence-related Cys protease phcp1. Accumulation of ABA, another hormone regulating flower senescence, was significantly greater in WT corollas, confirming that floral senescence was delayed in IPT plants. These results extend our understanding of the hormone interactions that regulate flower senescence and provide a means of increasing flower longevity.
Microarray Analysis of the Genome-Wide Response to Iron Deficiency and Iron Reconstitution in the Cyanobacterium Synechocystis sp. PCC 6803
Authors: Singh Abhay K. , McIntyre Lauren M. , Sherman Louis A.
Published: August 2003

A full-genome microarray of the (oxy)photosynthetic cyanobacterium Synechocystis sp. PCC 6803 was used to identify genes that were transcriptionally regulated by growth in iron (Fe)-deficient versus Fe-sufficient media. Transcript accumulation for 3,165 genes in the genome was analyzed using an analysis of variance model that accounted for slide and replicate (random) effects and dye (a fixed) effect in testing for differences in the four time periods. We determined that 85 genes showed statistically significant changes in the level of transcription (P ≤ 0.05/3,165 = 0.0000158) across the four time points examined, whereas 781 genes were characterized as interesting (P ≤ 0.05 but greater than 0.0000158; 731 of these had a fold change >1.25×). The genes identified included those known previously to be Fe regulated, such as isiA that encodes a novel chlorophyll-binding protein responsible for the pigment characteristics of low-Fe (LoFe) cells. ATP synthetase and phycobilisome genes were down-regulated in LoFe, and there were interesting changes in the transcription of genes involved in chlorophyll biosynthesis, in photosystem I and II assembly, and in energy metabolism. Hierarchical clustering demonstrated that photosynthesis genes, as a class, were repressed in LoFe and induced upon the re-addition of Fe. Specific regulatory genes were transcriptionally active in LoFe, including two genes that show homology to plant phytochromes (cph1 and cph2). These observations established the existence of a complex network of regulatory interactions and coordination in response to Fe availability.
Convergent Responses to Stress. Solar Ultraviolet-B Radiation and Manduca sexta Herbivory Elicit Overlapping Transcriptional Responses in Field-Grown Plants of Nicotiana longiflora
Authors: Izaguirre Miriam M. , Scopel Ana L. , Baldwin Ian T. , Ballaré Carlos L.
Published: August 2003

The effects of solar ultraviolet (UV)-B (280–315 nm) on plants have been studied intensively over the last 2 decades in connection with research on the biological impacts of stratospheric ozone depletion. However, the molecular mechanisms that mediate plant responses to solar (ambient) UV-B and their interactions with response mechanisms activated by other stressors remain for the most part unclear. Using a microarray enriched in wound- and insect-responsive sequences, we examined expression responses of 241 genes to ambient UV-B in field-grown plants of Nicotiana longiflora Cav. Approximately 20% of the sequences represented on the array showed differential expression in response to solar UV-B. The expression responses to UV-B had parallels with those elicited by simulated Manduca sexta herbivory. The most obvious similarities were: (a) down-regulation of several photosynthesis-related genes, and (b) up-regulation of genes involved in fatty acid metabolism and oxylipin biosynthesis such as HPL (hydroperoxide lyase), α-DIOX (alpha-dioxygenase), LOX (13-lipoxygenase), and AOS (allene oxide synthase). Genes encoding a WRKY transcription factor, a ferredoxin-dependent glutamate-synthase, and several other insect-responsive genes of unknown function were also similarly regulated by UV-B and insect herbivory treatments. Our results suggest that UV-B and caterpillar herbivory activate common regulatory elements and provide a platform for understanding the mechanisms of UV-B impacts on insect herbivory that have been documented in recent field studies.
Constitutive E2F Expression in Tobacco Plants Exhibits Altered Cell Cycle Control and Morphological Change in a Cell Type-Specific Manner
Authors: Kosugi Shunichi , Ohashi Yuko
Published: August 2003

The E2F family plays a pivotal role in cell cycle control and is conserved among plants and animals, but not in fungi. This provides for the possibility that the E2F family was integrated during the development of higher organisms, but little is known about this. We examined the effect of E2F ectopically expressed in transgenic tobacco (Nicotiana tabacum) plants on growth and development using E2Fa (AtE2F3) and DPa from Arabidopsis. E2Fa-DPa double transgenic lines exhibited altered phenotypes with curled leaves, round shaped petals, and shortened pistils. In mature but not immature leaves of the double transgenic lines, there were enlarged nuclei with increasing ploidy levels accompanied by the ectopic expression of S phase- but not M phase-specific genes. This indicates that a high expression of E2F promotes endoreduplication by accelerating S phase entry in terminally differentiated cells with limited mitotic activity. Furthermore, mature leaves of the transgenic plants contained increased numbers of small cells, especially on the palisade (adaxial) side of the outer region toward the edge, and the leaf strips exhibited hormone-independent callus formation when cultured in vitro. These observations suggest that an enhanced E2F activity modulates cell cycle in a cell type-specific manner and affects plant morphology depending on a balance between activities for committing to S phase and M phase, which likely differ between organs or tissues.
The Putative Arabidopsis Arp2/3 Complex Controls Leaf Cell Morphogenesis
Authors: Li Shundai , Blanchoin Laurent , Yang Zhenbiao , Lord Elizabeth M.
Published: August 2003

The evolutionarily conserved Arp2/3 complex has been shown to activate actin nucleation and branching in several eukaryotes, but its biological functions are not well understood in multicellular organisms. The model plant Arabidopsis provides many advantages for genetic dissection of the function of this conserved actin-nucleating machinery, yet the existence of this complex in plants has not been determined. We have identified Arabidopsis genes encoding homologs of all of the seven Arp2/3 subunits. The function of the putative Arabidopsis Arp2/3 complex has been studied using four homozygous T-DNA insertion mutants for ARP2, ARP3, and ARPC5/p16. All four mutants display identical defects in the development of jigsaw-shaped epidermal pavement cells and branched trichomes in the leaf. These loss-of-function mutations cause mislocalization of diffuse cortical F-actin to the neck region and inhibit lobe extension in pavement cells. The mutant trichomes resemble those treated with the actin-depolymerizing drug cytochalasin D, exhibiting stunted branches but dramatically enlarged stalks due to depolarized growth suggesting defects in the formation of a fine actin network. Our data demonstrate that the putative Arabidopsis Arp2/3 complex controls cell morphogenesis through its roles in cell polarity establishment and polar cell expansion. Furthermore, our data suggest a novel function for the putative Arp2/3 complex in the modulation of the spatial distribution of cortical F-actin and provide evidence that the putative Arp2/3 complex may activate the polymerization of some types of actin filaments in specific cell types.
Entrepreneurial image of demand in the Italian yarn firms
Authors: Guercini Simone
Published: August 2003

This paper presents an exploratory study on the activities undertaken by the top decision‐makers of the Italian yarn firms to define an image of demand in this sector for the next collections. The ability to construct an image of demand, which has been shown in the past to be effective, is hypothesised to represent a factor of power acting in favour of one or the other party within the framework of the relationship with the direct customer. This explorative study was conducted using statistical data gathered by means of a multimethodological base, which includes secondary research (statistical data on the Italian yarn industry and trade, previous research) and first results from a survey analysis of a sample of Italian yarn firms.
Gender differences in cognitive and affective impulse buying
Authors: Coley Amanda , Burgess Brigitte
Published: August 2003

The purpose of this study was to compare men and women for differences in affective and cognitive processes associated with impulse buying behavior and to identify gender differences in terms of impulsive purchases made from a variety of product categories. A total of 277 students served as the sample. Using analysis of variance tests, males and females were found to be significantly different with respect to affective process components (irresistible urge to buy, positive buying emotion and mood management) and cognitive process components (cognitive deliberation and unplanned buying). Significant differences were also found between men and women in the frequency with which the following product categories were purchased on impulse: shirts/sweaters, pants/skirts, coats, underwear/lingerie, accessories, shoes, electronics, hardware, computer software, music CDs or DVDs, sports memorabilia, health/beauty products, and magazines/books for pleasure reading.
Gender and Cardiovascular Disease
Authors: Stoney Catherine M.
Published: August 2003

Coronary artery disease is the most common cause of morbidity, mortality, and economic loss in all industrialized countries. Although there are gender differences in the prevalence, causes, symptoms, treatment, and outcome of heart disease, the differences are complex and often misunderstood. These gender differences are a function of psychological influences, physiological influences, and an interaction of the two. Understanding these complex interactions and how they differentially influence the development and progression of heart disease will ultimately contribute to a greater understanding of how to integrate information from medicine and epidemiology with that from psychology and behavioral medicine. Ultimately, it is this integrated approach that will allow us to better understand heart disease in both men and women.
Emotion recognition and social adjustment in school–aged girls and boys
Authors: Leppänen Jukka M. , Hietanen Jari K.
Published: August 2003

The present study investigated emotion recognition accuracy and its relation to social adjustment in 7–10 year–old children. The ability to recognize basic emotions from facial and vocal expressions was measured and compared to peer popularity and to teacher–rated social competence. The results showed that emotion recognition was related to these measures of social adjustment, but the gender of a child and emotion category affected this relationship. Emotion recognition accuracy was significantly related to social adjustment for the girls, but not for the boys. For the girls, especially the recognition of surprise was related to social adjustment. Together, these results suggest that the ability to recognize others’ emotional states from nonverbal cues is an important socio–cognitive ability for school–aged girls.
The Role of Joint Attention in Later Development Among Preterm Children: Linkages Between Early and Middle Childhood
Authors: Smith Lars , Ulvund Stein Erik
Published: August 2003

Joint attention is a hallmark of human cognition. It refers to the capacity to coordinate attention to objects and events with attention to other people. Infants display considerable individual differences in this capacity. This longitudinal study of 13‐month‐old preterms was conducted to examine the hypothesis that two different types of joint‐attention skills assessed in an infant–tester paradigm are related to verbal and nonverbal IQ measures through middle childhood. Data are reported separately for the children's tendency to initiate such skills and to respond to an experimenter's offers to share in such behaviours. The results provide support for the hypothesis that the initiation of joint attention makes a unique contribution to later nonverbal IQ apart from variance associated with biomedical risk status and infant development. The results of this study have implications for the conceptualisation of joint‐attention skills, as well as for understanding the relation between joint attention and later cognition.
Extremely Premature and Very Low Birthweight Infants: A Double Hazard Population?
Authors: Nadeau Line , Tessier Réjean , Boivin Michel , Lefebvre Francine , Robaey Philippe
Published: August 2003

This article evaluates the contributions of birth status (defined by gestational age and birthweight) and family adversity at birth and at age 7 to explaining behavior problems at age 7. The behaviors of 96 extremely preterm and very low birth‐weight children and 66 full‐term children were assessed in a school setting by peers, teachers and parents. The results show that a significant relationship exists between birth status and isolation and social withdrawal problems as well as between birth status and social immaturity and inattention problems. Family adversity at birth has a significant contribution to aggressive behaviors reported by the three sources whereas, at age 7, this index is associated only with aggressive behaviors and social immaturity problems reported by parents. In conclusion, the results of the present study qualify the findings of studies that suggest that at school age, the effect of prematurity decreases and that behavior problems are explained chiefly by family environment characteristics. Our results indicate that the findings must take into account the cohort studied, the environmental measures used, the type of behaviors assessed as well as the type of informants.
Plural marking, indefiniteness, and the noun phrase
Authors: Ghomeshi Jila
Published: August 2003

This article proposes that plural marking on nouns in Persian is licensed only if those nouns are contained within D/QPs. This proposal accounts for why plural‐marked nouns are construed as definite unless an overt marker of indefiniteness appears, and why plural marking does not cooccur with numerals unless the noun phrase is definite. It is also shown that the indefinite marker in Persian is quantitative rather than cardinal and is thus associated with higher functional structure within the noun phrase than in English. In English, on the other hand, number marking, the indefinite article, and the grammatical distinction between count and mass nouns, are all realized at the level of NumP. Differences in the interpretation of bare noun phrases in English and Persian are therefore explained by the claim that argument noun phrases must minimally be NumPs in English while Persian lacks this projection altogether.
Analysis of Quality of Life and Rural Development: Evidence from West Virginia Data
Authors: Bukenya James O. , Gebremedhin Tesfa G. , Schaeffer Peter V.
Published: August 2003

Abstract This paper examines the relationship between quality of life, rural development, and several socioeconomic variables. The analysis utilizes data obtained from a survey questionnaire administered to a random sample of more than 2,000 residents in West Virginia, and spatial data obtained by geocoding the survey respondents’ addressees. Quality of life is measured by a three‐point categorical measure of overall satisfaction, and development is measured by a goods and services availability index. A simultaneous ordered probit model is used to examine the relationships. The empirical results are consistent with the theoretical predictions and indicate a simultaneous relationship between quality of life satisfaction and rural development.
Urban land rent theory: a regulationist perspective
Authors: Jäger Johannes
Published: August 2003

Whilst real estate capital became a driving force in analyses of urban development, urban land rent theory has made only very limited progress during the past decade. There are a number of reasons for this – such as a weak conceptualization of the role of political agency, for example. Hence, a way out of this relative stagnation, by attempting to systematically develop an integrated view on structure and agency in the context of urban land rent, is offered in this article. Advances in critical theory, thinking about space and dialectic reasoning contribute to the development of a new perspective on land rent. Land rent is conceptualized as a middle‐range theory. In order to bring together concrete urban phenomena with the general process of political‐economic development, a systematic link between land rent theory and the theoretical apparatus of the French Regulation School is developed. The reformulation of land rent theory from a regulationist perspective underlines the importance of the institutional context (and its changes) for an understanding of rent and its role in the urban context. In so doing, land rent theory proves to be a very useful tool for providing an integrated political‐economic perspective for analyses of urban phenomena. This is illustrated briefly in the cases of Vienna and Montevideo.

Si le capital immobilier est devenu un point central des analyses du développement urbain, la théorie n'a guère progressé au cours de la dernière décennie. Plusieurs facteurs sont en cause, telle la faible conceptualisation du rôle politique d'agence. Cet article propose donc une porte de sortie à cette relative stagnation, en tentant de construire systématiquement une vision intégrée de la structure et l'agence dans le cadre de la rente urbaine. Les progrès en matière de théorie critique, réflexion en termes d'espace et raisonnement dialectique facilitent l'élaboration d'une nouvelle perspective sur la location foncière, laquelle est conceptualisée en tant que théorie intermédiaire. Afin de regrouper phénomènes urbains concrets et processus général d'aménagement politico‐économique, une relation systématique est établie entre la théorie sur la rente foncière et l'appareil théorique de l'École Française de Régulation. Reformuler la théorie sur la rente foncière d'un point de vue régulationiste souligne combien le contexte institutionnel (et ses changements) est important pour comprendre la rente et son rôle dans le cadre urbain. Ce faisant, la théorie sur la rente foncière se révèle un outil très utile pour créer une perspective politico‐économique intégrée permettant d'analyser les phénomènes urbains. Cet aspect est brièvement illustré dans les cas de Vienne et Montevideo.
Maquiladora industrialization of the Baja California peninsula: the coexistence of thick and thin globalization with economic regionalism
Authors: Kopinak Kathryn
Published: August 2003

This article assesses the shape of industrial growth at the western end of the US‐Mexican border, analysing the degree to which globalization has diminished and/or restructured this international division. Baja California's connection to external economies is highly variable in tourism, agribusiness and export processing, with electronic maquiladoras clustering and garment production fragmenting. Most recently, dynamism has been driven by Asian investors meeting NAFTA deadlines, and impeded by recession and increased border security. The polarizing effect of globalization is demonstrated by the unprecedented emergence of a powerful group of Mexican‐state and private‐sector technocrats, at the expense of the majority of workers whose jobs remain poor. The state government has facilitated the development of capital intensive electronics industries, has neglected small and medium domestic suppliers, and been unable to provide public security. Low extensity, or the concentration of maquiladoras in an east‐west corridor adjacent to the border, and the location of most of their owners in Southern California, indicates the strongly regional character of the maquiladora economy. However, a small number of very large capital intensive plants originate in Asia, contributing to globalization via intercontinental linkages. The findings support transformationalist and sceptical models of globalization.

L'article évalue la forme de croissance industrielle à l'extrémité occidentale de la frontière américano‐mexicaine, en analysant dans quelle mesure la mondialisation a atténué et/ou restructuré cette séparation internationale. La péninsule de Basse Californie est reliée de façon très variable aux économies extérieures, par le tourisme, l'agro‐industrie et la transformation à l'exportation, avec un regroupement de maquiladoras d'électronique et une fragmentation de la production vestimentaire. Plus récemment, si le dynamisme est venu d'investisseurs asiatiques en des échéances de l'ALENA, il a été entravé par la récession et une sécurité frontalière accrue. L'effet polarisant de la mondialisation est réävélé par l'émergence d'un puissant groupe de technocrates du secteur privé et de lÉtat mexicain, aux dépens de la majorité des salariés dont les emplois restent médiocres. Négligeant les petits et moyens fournisseurs nationaux, le gouvernement a facilité l'essor de secteurs capitalistiques de l'électronique, tout en se montrant incapable d'assurer la sécurité publique. La faible extensibilité ou la concentration des maquiladoras sur une bande Est‐Ouest longeant la frontière, ainsi que l'implantation de la plupart de leur propriétaire dans le sud de la Californie, marquent le caractère fortement régional de ce type d'économie. Toutefois, un petit nombre de très grosses usines capitalistiques viennent d'Asie, contribuant à la mondialisation via des liens intercontinentaux. Les résultats corroborent les modèles de transformation et sceptique de la mondialisation.
The limits of branding: the World Trade Center, fiscal crisis and the marketing of recovery
Authors: Greenberg Miriam
Published: August 2003

This article investigates the branding of New York's World Trade Center, and the city itself, as both financial center and entertainment destination between the 1960s and 1990s. After addressing the symbolic as well as material damage caused by the terrorist attacks of September 11th, the article traces the history behind the towers' design and ultimate use in marketing. It first examines the early motivations behind the project, and the forces leading to its controversial construction in the 1960s–70s. Then, in the wake of the city's 1975 fiscal crisis, the Twin Towers and Downtown skyline were branded through campaigns like ‘I ♡ NY’ to represent a resurgent, global New York. With the recession of 1989–92, and the scaling back of public‐sector marketing, this new brand was used by a host of private‐sector media and marketing firms then establishing global headquarters in New York. In the current period, the site of the towers, and the city as a whole, are being ‘re‐branded’ as a patriotic destination. Building on content analysis and archival research, the article critically analyzes how such marketing became central to New York City's overall economic development strategy.

Cet article étudie la stratégie de marque qui a étiqueté le World Trade Center de New York et la ville elle‐mäme, en tant que centre financier et destination de loisirs des années 1960 à 1990. Après avoir traité les préjudices symboliques et matériels liés aux attaques terroristes du 11 septembre, l'article retrace l'histoire de la conception des tours et leur exträme utilisation en marketing. Il examine d'abord les premières motivations du projet et les forces qui ont conduità sa construction controversée dans les années 1960–70. Suite à la crise fiscale de la ville en 1975, les Tours jumelles et la silhouette des immeubles du centre ont ensuite été choisies dans le cadre de campagnes comme ‘I ♡ NY’ (J'aime New York) afin de représenter un New York ressuscité et mondialisé. Après la récession de 1989–92, et la réduction du marketing public, cette nouvelle ‘étiquette’ a servi à une foule d'entreprises privées de médias et marketing qui ont alors installé leur siège international à New York. Actuellement, le site des tours, et la ville dans son ensemble, sont en train d'ätre ‘ré‐étiquetés’ comme destination patriotique. A partir d'une analyse de contenu et de recherches d'archives, l'article scrute la façon dont ce marketing est devenu essentiel à la stratégie de développement économique globale de la ville de New York.