bluuebunny/crossref_metadata_2025 huggingface dataset:
Phytochrome D Acts in the Shade-Avoidance Syndrome in Arabidopsis by Controlling Elongation Growth and Flowering Time1
Authors: Devlin Paul F. , Robson Paul R.H. , Patel Samita R. , Goosey Lynn , Sharrock Robert A. , Whitelam Garry C.
Published: July 2002

Shade avoidance in higher plants is regulated by the action of multiple phytochrome (phy) species that detect changes in the red/far-red ratio (R/FR) of incident light and initiate a redirection of growth and an acceleration of flowering. The phyB mutant of Arabidopsis is constitutively elongated and early flowering and displays attenuated responses to both reduced R/FR and end-of-day far-red light, conditions that induce strong shade-avoidance reactions in wild-type plants. This indicates that phyB plays an important role in the control of shade avoidance. In Arabidopsis phyB and phyD are the products of a recently duplicated gene and share approximately 80% identity. We investigated the role played by phyD in shade avoidance by analyzing the responses of phyD-deficient mutants. Compared with the monogenic phyB mutant, the phyB-phyDdouble mutant flowers early and has a smaller leaf area, phenotypes that are characteristic of shade avoidance. Furthermore, compared with the monogenic phyB mutant, the phyB-phyDdouble mutant shows a more attenuated response to a reduced R/FR for these responses. Compared with the phyA-phyB double mutant, the phyA-phyB-phyD triple mutant has elongated petioles and displays an enhanced elongation of internodes in response to end-of-day far-red light. These characteristics indicate that phyD acts in the shade-avoidance syndrome by controlling flowering time and leaf area and that phyC and/or phyE also play a role.
Isolation of Ethylene-Insensitive Soybean Mutants That Are Altered in Pathogen Susceptibility and Gene-for-Gene Disease Resistance1
Authors: Hoffman Thomas , Schmidt J. Scott , Zheng Xiangyang , Bent Andrew F.
Published: July 2002

Plants commonly respond to pathogen infection by increasing ethylene production, but it is not clear if this ethylene does more to promote disease susceptibility or disease resistance. Ethylene production and/or responsiveness can be altered by genetic manipulation. The present study used mutagenesis to identify soybean (Glycine max L. Merr.) lines with reduced sensitivity to ethylene. Two new genetic loci were identified,Etr1 and Etr2. Mutants were compared with isogenic wild-type parents for their response to different soybean pathogens. Plant lines with reduced ethylene sensitivity developed similar or less-severe disease symptoms in response to virulentPseudomonas syringae pv glycinea andPhytophthora sojae, but some of the mutants developed similar or more-severe symptoms in response to Septoria glycines and Rhizoctonia solani. Gene-for-gene resistance against P. syringae expressingavrRpt2 remained effective, butRps1-k-mediated resistance against P. sojae races 4 and 7 was disrupted in the strong ethylene-insensitive etr1-1 mutant.Rps1-k-mediated resistance against P. sojae race 1 remained effective, suggesting that theRps1-k locus may encode more than one gene for disease resistance. Overall, our results suggest that reduced ethylene sensitivity can be beneficial against some pathogens but deleterious to resistance against other pathogens.
Inhibition of Nitrate Uptake by Ammonium in Barley. Analysis of Component Fluxes1
Authors: Kronzucker Herbert J. , Glass Anthony D.M. , Siddiqi M. Yaeesh
Published: July 2002

NO3− uptake by plant roots is rapidly inhibited by exposure to NH4+. The rapidity of the effect has led to the presumption that the inhibition results from the direct effects of NH4+ at the plasma membrane. The mechanism of this inhibition, however, has been in contention. In the present study we used the radiotracer 13N to determine the relative effects of short-term exposures to NH4+ on the13NO3− influx, efflux, and partitioning of absorbed 13N in barley (Hordeum vulgare) roots. Plants were grown without NO3− or NO2−(uninduced for NO3− uptake), or with 0.1, 1.0, 10 mm NO3−, or 0.1 mmNO2− (to generate plant roots induced for NO3− uptake). Exposure to 1 mmNH4+ strongly reduced influx; the effect was most pronounced in plants induced for NO3−uptake when NO3− absorption was measured at low external NO3−. At higher [NO3−] and in uninduced plants the inhibitory effect was much diminished, indicating that NH4+ inhibition of influx was mediated via effects on the inducible high-affinity transport system rather than on the constitutive high-affinity transport system or the low-affinity transport system. Exposure to NH4+ also caused increased NO3− efflux; the largest effect was at low external [NO3−] in uninduced plants. In absolute terms, the reduction of influx made the dominant contribution to the observed reduction of net uptake of NO3−. Differences in response between plants induced with NO3− and those induced with NO2− indicate that NO2− may not be an appropriate analog for NO3− under all conditions.
PsbU, a Protein Associated with Photosystem II, Is Required for the Acquisition of Cellular Thermotolerance inSynechococcus species PCC 70021
Authors: Nishiyama Yoshitaka , Los Dmitry A. , Murata Norio
Published: July 2002

PsbU is an extrinsic protein of the photosystem II complex of cyanobacteria and red algae. Our previous in vitro studies (Y. Nishiyama, D.A. Los, H. Hayashi, N. Murata [1997] Plant Physiol 115: 1473–1480) revealed that PsbU stabilizes the oxygen-evolving machinery of the photosystem II complex against heat-induced inactivation in the cyanobacteriumSynechococcus sp. PCC 7002. To elucidate the role of PsbU in vivo, we inactivated the psbU gene inSynechococcus sp. PCC 7002 by targeted mutagenesis. Inactivation of the psbU gene resulted in marked changes in the acclimative responses of cells to high temperature: Mutated cells were unable to increase the thermal stability of their oxygen-evolving machinery when grown at moderately high temperatures. Moreover, the cellular thermotolerance of the mutated cells failed to increase upon acclimation of cells to high temperature. The heat-shock response, as assessed in terms of the levels of homologs of the heat-shock proteins Hsp60, Hsp70, and Hsp17, was unaffected by the mutation in psbU, suggesting that heat-shock proteins were not involved in the changes in the acclimative responses. Our observations indicate that PsbU is involved in the mechanism that underlies the enhancement of the thermal stability of the oxygen-evolving machinery and that the stabilization of the oxygen-evolving machinery is crucial for the acquisition of cellular thermotolerance.
Hydrogen Peroxide from the Oxidative Burst Is Neither Necessary Nor Sufficient for Hypersensitive Cell Death Induction, Phenylalanine Ammonia Lyase Stimulation, Salicylic Acid Accumulation, or Scopoletin Consumption in Cultured Tobacco Cells Treated with Elicitin
Authors: Dorey Stéphan , Kopp Marguerite , Geoffroy Pierrette , Fritig Bernard , Kauffmann Serge
Published: July 2002

H2O2 from the oxidative burst, cell death, and defense responses such as the production of phenylalanine ammonia lyase (PAL), salicylic acid (SA), and scopoletin were analyzed in cultured tobacco (Nicotiana tabacum) cells treated with three proteinaceous elicitors: two elicitins (α-megaspermin and β-megaspermin) and one glycoprotein. These three proteins have been isolated from Phytophthora megasperma H20 and have been previously shown to be equally efficient in inducing a hypersensitive response (HR) upon infiltration into tobacco leaves. However, in cultured tobacco cells these elicitors exhibited strikingly different biological activities. β-Megaspermin was the only elicitor that caused cell death and induced a strong, biphasic H2O2 burst. Both elicitins stimulated PAL activity similarly and strongly, while the glycoprotein caused only a slight increase. Only elicitins induced SA accumulation and scopoletin consumption, and β-megaspermin was more efficient. To assess the role of H2O2 in HR cell death and defense response expression in elicitin-treated cells, a gain and loss of function strategy was used. Our results indicated that H2O2 was neither necessary nor sufficient for HR cell death, PAL activation, or SA accumulation, and that extracellular H2O2 was not a direct cause of intracellular scopoletin consumption.
Arabidopsis Mutants Lacking the 43- and 54-Kilodalton Subunits of the Chloroplast Signal Recognition Particle Have Distinct Phenotypes
Authors: Amin Pinky , Sy Donna A.C. , Pilgrim Marsha L. , Parry Devin H. , Nussaume Laurent , Hoffman Neil E.
Published: July 2002

The chloroplast signal recognition particle (cpSRP) is a protein complex consisting of 54- and 43-kD subunits encoded by the fifty-four chloroplast, which encodes cpSRP54 (ffc), and chaos (cao) loci, respectively. Two new null alleles in the ffc locus have been identified.ffc1-1 is caused by a stop codon in exon 10, whileffc1-2 has a large DNA insertion in intron 8.ffc mutants have yellow first true leaves that subsequently become green. The reaction center proteins D1, D2, and psaA/B, as well as seven different light-harvesting chlorophyll proteins (LHCPs), were found at reduced levels in the youngffc leaves but at wild-type levels in the older leaves. The abundance of the two types of LHCP was unaffected by the mutation, while two others were increased in the absence of cpSRP54. Null mutants in the cao locus contain reduced levels of the same subset of LHCP proteins as ffc mutants, but are distinguishable in four ways: young leaves are greener, the chlorophylla/b ratio is elevated, levels of reaction center proteins are normal, and there is no recovery in the level of LHCPs in the adult plant. The data suggest that cpSRP54 and cpSRP43 have some nonoverlapping roles and that alternative transport pathways can compensate for the absence of a functional cpSRP.
Analysis of the Relative Increase in Photosynthetic O2 Uptake When Photosynthesis in Grapevine Leaves Is Inhibited following Low Night Temperatures and/or Water Stress
Authors: Flexas Jaume , Badger Murray , Chow Wah Soon , Medrano Hipólito , Osmond Charles Barry
Published: July 2002

We found similarities between the effects of low night temperatures (5°C–10°C) and slowly imposed water stress on photosynthesis in grapevine (Vitis vinifera L.) leaves. Exposure of plants growing outdoors to successive chilling nights caused light- and CO2-saturated photosynthetic O2 evolution to decline to zero within 5 d. Plants recovered after four warm nights. These photosynthetic responses were confirmed in potted plants, even when roots were heated. The inhibitory effects of chilling were greater after a period of illumination, probably because transpiration induced higher water deficit. Stomatal closure only accounted for part of the inhibition of photosynthesis. Fluorescence measurements showed no evidence of photoinhibition, but nonphotochemical quenching increased in stressed plants. The most characteristic response to both stresses was an increase in the ratio of electron transport to net O2evolution, even at high external CO2 concentrations. Oxygen isotope exchange revealed that this imbalance was due to increased O2 uptake, which probably has two components: photorespiration and the Mehler reaction. Chilling- and drought-induced water stress enhanced both O2 uptake processes, and both processes maintained relatively high rates of electron flow as CO2 exchange approached zero in stressed leaves. Presumably, high electron transport associated with O2uptake processes also maintained a high ΔpH, thus affording photoprotection.
Molecular Dissection of the Role of Histidine in Nickel Hyperaccumulation in Thlaspi goesingense(Hálácsy)
Authors: Persans Michael W. , Yan Xiange , Patnoe Jean-Marc M.L. , Krämer Ute , Salt David E.
Published: July 2002

To understand the role of free histidine (His) in Ni hyperaccumulation in Thlaspi goesingense, we investigated the regulation of His biosynthesis at both the molecular and biochemical levels. Three T. goesingense cDNAs encoding the following His biosynthetic enzymes, ATP phosphoribosyltransferase (THG1, GenBank accession no. AF003347), imidazoleglycerol phosphate dehydratase (THB1, GenBank accession no. AF023140), and histidinol dehydrogenase (THD1, GenBank accession no. AF023141) were isolated by functional complementation of Escherichia coli His auxotrophs. Northern analysis of THG1,THD1, and THB1 gene expression revealed that each gene is expressed in both roots and shoots, but at the concentrations and dosage times of Ni treatment used in this study, these genes failed to show any regulation by Ni. We were also unable to observe any increases in the concentration of free His in root, shoot, or xylem sap of T. goesingense in response to Ni exposure. X-ray absorption spectroscopy of root and shoot tissue fromT. goesingense and the non-accumulator speciesThlaspi arvense revealed no major differences in the coordination of Ni by His in these tissues. We therefore conclude that the Ni hyperaccumulation phenotype in T. goesingense is not determined by the overproduction of His in response to Ni.
Sustained Photobiological Hydrogen Gas Production upon Reversible Inactivation of Oxygen Evolution in the Green AlgaChlamydomonas reinhardtii
Authors: Melis Anastasios , Zhang Liping , Forestier Marc , Ghirardi Maria L. , Seibert Michael
Published: July 2002

The work describes a novel approach for sustained photobiological production of H2 gas via the reversible hydrogenase pathway in the green alga Chlamydomonas reinhardtii. This single-organism, two-stage H2 production method circumvents the severe O2 sensitivity of the reversible hydrogenase by temporally separating photosynthetic O2 evolution and carbon accumulation (stage 1) from the consumption of cellular metabolites and concomitant H2 production (stage 2). A transition from stage 1 to stage 2 was effected upon S deprivation of the culture, which reversibly inactivated photosystem II (PSII) and O2 evolution. Under these conditions, oxidative respiration by the cells in the light depleted O2 and caused anaerobiosis in the culture, which was necessary and sufficient for the induction of the reversible hydrogenase. Subsequently, sustained cellular H2 gas production was observed in the light but not in the dark. The mechanism of H2 production entailed protein consumption and electron transport from endogenous substrate to the cytochromeb  6-f and PSI complexes in the chloroplast thylakoids. Light absorption by PSI was required for H2 evolution, suggesting that photoreduction of ferredoxin is followed by electron donation to the reversible hydrogenase. The latter catalyzes the reduction of protons to molecular H2in the chloroplast stroma.
Lignification in Transgenic Poplars with Extremely Reduced Caffeic Acid O-Methyltransferase Activity
Authors: Jouanin Lise , Goujon Thomas , de Nadaı̈ Véronique , Martin Marie-Thérèse , Mila Isabelle , Vallet Christelle , Pollet Brigitte , Yoshinaga Arata , Chabbert Brigitte , Petit-Conil Michel , Lapierre Catherine
Published: July 2002

Transgenic poplars (Populus tremula ×Populus alba) were obtained by introduction of a sense homologous transgene encoding caffeic acidO-methyltransferase (COMT) under the control either of the cauliflower mosaic virus double 35S promoter or of the eucalyptus cinnamyl alcohol dehydrogenase promoter. Although these constructs conferred a moderate overexpression of COMT in some lines, a transgenic line with the double 35S promoter was found where COMT activity in woody tissues was close to zero due to a gene-silencing phenomenon. For the first time in COMT down-regulated trees, this alteration substantially reduced lignin level in 6-month-old trees (17% decrease). Lignin structure was found to be strongly altered, with a two times higher content in condensed bonds, an almost complete lack of syringyl units, and the incorporation of 5-hydroxyguaiacyl units to the most remarkable extent reported so far. Consistent with the higher cellulose content and with the higher condensation degree of the lignin, the impact of the transformation on the kraft-pulping performances of the poplar trees positively affected the pulp yield (10% relative increase), but made lignins less amenable to industrial degradations.
Production and Characterization of Diverse Developmental Mutants of Medicago truncatula
Authors: Penmetsa R. Varma , Cook Douglas R.
Published: July 2002

The diploid annual legume Medicago truncatula has been developed as a tractable genetic system for studying biological questions that are unique to, or well suited for study in legume species. An efficient mutagenesis protocol using ethyl-methyl sulfonate and a polymorphic ecotype with properties appropriate for use as a mapping parent are described. Isolation and characterization of three developmental mutants are described. The mtapetalamutation results in homeotic conversions of floral organ whorls 2 and 3 into sepals and carpelloid structures, respectively, similar to mutations in the apetala3/pistillata genes of Arabidopsis. The palmyra mutation primarily affects seedling shoot meristem initiation, and thus phenocopies meristem function mutations identified in Arabidopsis such as thezwille locus. The phenotype of thepalmyra and mtapetala double mutant is additive, with seedling shoot meristems and floral organs indistinguishable from those of the single palmyra andmtapetala mutants, respectively. These results are consistent with a lack of genetic interaction between these loci. A third mutant, speckle, is characterized by spontaneous necrotic lesion formation on leaves, root, and stems, similar to necrosis mutants identified in other plant species. In addition to documenting the efficient mutagenesis of M. truncatula, the availability of developmental mutants that phenocopy characterized Arabidopsis mutants will provide a basis for establishing orthologous gene function between M. truncatula and Arabidopsis, once the genes responsible are cloned. Moreover, the male-sterile, female-fertile nature of the mtapetala mutant provides a convenient tool for genetic analyses in M. truncatula.
Mollusc-Algal Chloroplast Endosymbiosis. Photosynthesis, Thylakoid Protein Maintenance, and Chloroplast Gene Expression Continue for Many Months in the Absence of the Algal Nucleus
Authors: Green Brian J. , Li Wei-Ye , Manhart James R. , Fox Theodore C. , Summer Elizabeth J. , Kennedy Robert A. , Pierce Sidney K. , Rumpho Mary E.
Published: July 2002

Early in its life cycle, the marine mollusc Elysia chlorotica Gould forms an intracellular endosymbiotic association with chloroplasts of the chromophytic alga Vaucheria litorea C. Agardh. As a result, the dark green sea slug can be sustained in culture solely by photoautotrophic CO2fixation for at least 9 months if provided with only light and a source of CO2. Here we demonstrate that the sea slug symbiont chloroplasts maintain photosynthetic oxygen evolution and electron transport activity through photosystems I and II for several months in the absence of any external algal food supply. This activity is correlated to the maintenance of functional levels of chloroplast-encoded photosystem proteins, due in part at least to de novo protein synthesis of chloroplast proteins in the sea slug. Levels of at least one putative algal nuclear encoded protein, a light-harvesting complex protein homolog, were also maintained throughout the 9-month culture period. The chloroplast genome ofV. litorea was found to be 119.1 kb, similar to that of other chromophytic algae. Southern analysis and polymerase chain reaction did not detect an algal nuclear genome in the slug, in agreement with earlier microscopic observations. Therefore, the maintenance of photosynthetic activity in the captured chloroplasts is regulated solely by the algal chloroplast and animal nuclear genomes.
Gibberellin-Induced Changes in Growth Anisotropy Precede Gibberellin-Dependent Changes in Cortical Microtubule Orientation in Developing Epidermal Cells of Barley Leaves. Kinematic and Cytological Studies on a Gibberellin-Responsive Dwarf Mutant, M489
Authors: Wenzel Carol L. , Williamson Richard E. , Wasteneys Geoffrey O.
Published: July 2002

We conducted kinematic and cytological studies on “between vein” epidermal cells of the gibberellin (GA)-deficient M489 dwarf mutant of barley (Hordeum vulgare L. Himalaya). GAs affect radial and axial components of cell expansion and cortical microtubule orientation. Adaxial cells in particular expand radially after leaving the elongation zone (EZ), probably as part of leaf unrolling. Exogenous gibberellic acid corrects the mutant's short, wide blades, short EZ, and slow elongation rate. Cell production rates increase more on the adaxial than on the abaxial surface. Cells spend equal periods of time elongating in dwarf and tall plants, but relative elemental growth rates start to decline sooner in the dwarf. GA increased the rate at which longitudinal wall area increased because the increased axial growth more than compensated for reduced radial growth. In dwarf leaves, increased radial expansion was detected in basal parts of the EZ before cortical microtubules lost transverse orientation in the distal elongation zone. We conclude that loss of microtubule orientation is not required for low GA levels to reduce growth anisotropy.
Genetic Analysis of Seed-Soluble Oligosaccharides in Relation to Seed Storability of Arabidopsis
Authors: Bentsink Leónie , Alonso-Blanco Carlos , Vreugdenhil Dick , Tesnier Karine , Groot Steven P.C. , Koornneef Maarten
Published: July 2002

Seed oligosaccharides (OSs) and especially raffinose series OSs (RSOs) are hypothesized to play an important role in the acquisition of desiccation tolerance and consequently in seed storability. In the present work we analyzed the seed-soluble OS (sucrose, raffinose, and stachyose) content of several Arabidopsis accessions and thus identified the genotype Cape Verde Islands having a very low RSO content. By performing quantitative trait loci (QTL) mapping in a recombinant inbred line population, we found one major QTL responsible for the practically monogenic segregation of seed stachyose content. This locus also affected the content of the two other OSs, sucrose, and raffinose. Two candidate genes encoding respectively for galactinol synthase and raffinose synthase were located within the genomic region around this major QTL. In addition, three smaller-effect QTL were identified, each one specifically affecting the content of an individual OS. Seed storability was analyzed in the same recombinant inbred line population by measuring viability (germination) under two different seed aging assays: after natural aging during 4 years of dry storage at room temperature and after artificial aging induced by a controlled deterioration test. Thus, four QTL responsible for the variation of this trait were mapped. Comparison of the QTL genetic positions showed that the genomic region containing the major OS locus did not significantly affect the seed storability. We concluded that in the studied material neither RSOs nor sucrose content had a specific effect on seed storability.
Subcellular Compartmentation of the Diterpene Carnosic Acid and Its Derivatives in the Leaves of Rosemary
Authors: Munné-Bosch Sergi , Alegre Leonor
Published: July 2002

The potent antioxidant properties of rosemary (Rosmarinus officinalis) extracts have been attributed to its major diterpene, carnosic acid. Carnosic acid has received considerable attention in food science and biomedicine, but little is known about its function in the plant in vivo. We recently found that highly oxidized diterpenes increase in rosemary plants exposed to drought and high light stress as a result of the antioxidant activity of carnosic acid (S. Munné-Bosch, K. Schwarz, L. Alegre [1999] Plant Physiol 121: 1047–1052). To elucidate the significance of the antioxidant function of carnosic acid in vivo we measured the relative amounts of carnosic acid and its metabolites in different compartments of rosemary leaves. Subcellular localization studies show that carnosic acid protects chloroplasts from oxidative stress in vivo by following a highly regulated compartmentation of oxidation products. Carnosic acid scavenges free radicals within the chloroplasts, giving rise to diterpene alcohols, mainly isorosmanol. This oxidation product isO-methylated within the chloroplasts, and the resulting form, 11,12-di-O-methylisorosmanol, is transferred to the plasma membrane. This appears to represent a mechanism of a way out for free radicals from chloroplasts. Carnosic acid also undergoes direct O-methylation within the chloroplasts, and its derived product, 12-O-methylcarnosic acid, accumulates in the plasma membrane. O-methylated diterpenes do not display antioxidant activity, but they may influence the stability of the plasma membrane. This study shows the relevance of the compartmentation of carnosic acid metabolism to the protection of rosemary plants from oxidative stress in vivo.
Effect of Solar Ultraviolet-B Radiation during Springtime Ozone Depletion on Photosynthesis and Biomass Production of Antarctic Vascular Plants
Authors: Xiong Fusheng S. , Day Thomas A.
Published: July 2002

We assessed the influence of springtime solar UV-B radiation that was naturally enhanced during several days due to ozone depletion on biomass production and photosynthesis of vascular plants along the Antarctic Peninsula. Naturally growing plants of Colobanthus quitensis (Kunth) Bartl. and Deschampsia antarctica Desv. were potted and grown under filters that absorbed or transmitted most solar UV-B. Plants exposed to solar UV-B from mid-October to early January produced 11% to 22% less total, as well as above ground biomass, and 24% to 31% less total leaf area. These growth reductions did not appear to be associated with reductions in photosynthesis per se: Although rates of photosynthetic O2 evolution were reduced on a chlorophyll and a dry-mass basis, on a leaf area basis they were not affected by UV-B exposure. Leaves on plants exposed to UV-B were denser, probably thicker, and had higher concentrations of photosynthetic and UV-B absorbing pigments. We suspect that the development of thicker leaves containing more photosynthetic and screening pigments allowed these plants to maintain their photosynthetic rates per unit leaf area. Exposure to UV-B led to reductions in quantum yield of photosystem II, based on fluorescence measurements of adaxial leaf surfaces, and we suspect that UV-B impaired photosynthesis in the upper mesophyll of leaves. Because the ratio of variable to maximal fluorescence, as well as the initial slope of the photosynthetic light response, were unaffected by UV-B exposure, we suggest that impairments in photosynthesis in the upper mesophyll were associated with light-independent enzymatic, rather than photosystem II, limitations.
The Salt Stress-Inducible Protein Kinase Gene, Esi47, from the Salt-Tolerant WheatgrassLophopyrum elongatum Is Involved in Plant Hormone Signaling
Authors: Shen Wei , Gómez-Cadenas Aurelio , Routly Elizabeth L. , Ho Tuan-Hua David , Simmonds John A. , Gulick Patrick J.
Published: July 2002

Protein kinases play a central role in signal transduction in all organisms and to study signal transduction in response to salt stress we have identified and characterized a gene encoding a protein kinase that is induced by salt stress and abscisic acid (ABA) in the salt-tolerant wild wheatgrass Lophopyrum elongatum(Host) A. Love. The product of the early salt stress-induced gene,Esi47, was found to belong to the “novel Arabidopsis protein kinase” group of plant serine/threonine protein kinases. Transient gene expression assays in barley aleurone tissue showedEsi47 to suppress the gibberellin induction of the barley low-pI α-amylase gene promoter, thus providing evidence for the role of this protein kinase gene in plant hormone signaling.Esi47 contains a small upstream open reading frame in the 5′-untranslated region of its transcript that is implicated in mediating the repression of the basal level of the gene expression and in regulating the ABA inducibility of the gene, as shown in the transient gene expression assay in maize callus. Three Arabidopsis homologs of Esi47 were identified, and different members of this clade of genes showed differential patterns of regulation by salt stress and ABA in Arabidopsis roots and leaves. At least one of the Arabidopsis homologs contains a small open reading frame in its 5′-untranslated region, indicating that the unusual regulatory mechanism identified in Esi47 may be widely conserved.
Cooperative Action of SLR1 and SLR2 Is Required for Lateral Root-Specific Cell Elongation in Maize
Authors: Hochholdinger Frank , Park Woong June , Feix Günter H.
Published: July 2002

Lateral roots play an important role in water and nutrient uptake largely by increasing the root surface area. In an effort to characterize lateral root development in maize (Zea mays), we have isolated from Mutator(Mu) transposon stocks and characterized two nonallelic monogenic recessive mutants: slr1 andslr2 (short lateral roots1 and2), which display short lateral roots as a result of impaired root cell elongation. The defects in both mutants act specifically during early postembryonic root development, affecting only the lateral roots emerging from the embryonic primary and seminal roots but not from the postembryonic nodal roots. These mutations have no major influence on the aboveground performance of the affected plants. The double mutant slr1; slr2 displays a strikingly different phenotype than the single mutants. The defect inslr1; slr2 does not only influence lateral root specific cell elongation, but also leads to disarranged cellular patterns in the primary and seminal roots. However, the phase-specific nature of the single mutants is retained in the double mutant, indicating that the two loci cooperate in the wild type to maintain the lateral root specificity during a short time of early root development.
Carrier-Mediated Uptake and Phloem Systemy of a 350-Dalton Chlorinated Xenobiotic with an α-Amino Acid Function
Authors: Delétage-Grandon Céline , Chollet Jean-François , Faucher Mireille , Rocher Francoise , Komor Ewald , Bonnemain Jean-Louis
Published: July 2002

In a previous paper we have shown that ε-(phenoxyalkanecarboxylyl)-l-Lys conjugates are potent inhibitors of amino acid transport systems and that it is possible to modulate the uptake inhibition by hydrophobic or hydrophilic additions in the 4-position of the aromatic ring (J.F. Chollet, C. Delétage, M. Faucher, L. Miginiac, J.L. Bonnemain [1997] Biochem Biophys Acta 1336: 331–341). In this report we demonstrate that ε-(2,4-dichlorophenoxyacetyl)-l-Lys (2,4D-Lys), one of the largest molecules of the series and one of the most potent inhibitors, is a highly permeant conjugate. Uptake of 2,4D-Lys by broad bean (Vicia faba) leaf discs is mediated by an active carrier system (K  m1 = 0.2 mm;V  max1 = 2.4 nmol cm−2h−1 at pH 5.0) complemented by an important diffusive component. Among the compounds tested (neutral, basic, and acidic amino acids, auxin, glutathione, and sugars), only the aromatic amino acids clearly compete with 2,4D-Lys. The conjugate accumulates in the vein network, is exported toward the growing organs, and exhibits a distribution pattern different from that of the herbicide moiety. However, over time 2,4D-Lys progressively splits into 2,4D and lysine. Analyses by high-performance liquid chromatography and liquid scintillation spectrometry of the phloem sap collected from the castor bean system, used as a systemy test, indicate decreasing capacities of 2,4D, 2,4D-Lys, and glyphosate, respectively, to move from the epidermis cell wall to the sieve element. Our results show that it is possible to design synthesis of large-size xenobiotics (approximately 350 D) with a lipophilic pole, exhibiting high mobility within the vascular system.
A New Approach to Measure Gross CO2 Fluxes in Leaves. Gross CO2 Assimilation, Photorespiration, and Mitochondrial Respiration in the Light in Tomato under Drought Stress
Authors: Haupt-Herting Silke , Klug Klaus , Fock Heinrich P.
Published: July 2002

We developed a new method using 13CO2 and mass spectrometry to elucidate the role of photorespiration as an alternative electron dissipating pathway under drought stress. This was achieved by experimentally distinguishing between the CO2fluxes into and out of the leaf. The method allows us to determine the rates of gross CO2 assimilation and gross CO2evolution in addition to net CO2 uptake by attached leaves during steady-state photosynthesis. Furthermore, a comparison between measurements under photorespiratory and non-photorespiratory conditions may give information about the contribution of photorespiration and mitochondrial respiration to the rate of gross CO2evolution at photosynthetic steady state. In tomato (Lycopersicon esculentum Mill. cv Moneymaker) leaves, drought stress decreases the rates of net and gross CO2uptake as well as CO2 release from photorespiration and mitochondrial respiration in the light. However, the ratio of photorespiratory CO2 evolution to gross CO2assimilation rises with water deficit. Also the contribution of re-assimilation of (photo) respiratory CO2 to gross CO2 assimilation increases under drought.
Role of Auxin-Induced Reactive Oxygen Species in Root Gravitropism
Authors: Joo Jung Hee , Bae Yun Soo , Lee June Seung
Published: July 2002

We report our studies on root gravitropism indicating that reactive oxygen species (ROS) may function as a downstream component in auxin-mediated signal transduction. A transient increase in the intracellular concentration of ROS in the convex endodermis resulted from either gravistimulation or unilateral application of auxin to vertical roots. Root bending was also brought about by unilateral application of ROS to vertical roots pretreated with the auxin transport inhibitor N-1-naphthylphthalamic acid. Furthermore, the scavenging of ROS by antioxidants (N-acetylcysteine, ascorbic acid, and Trolox) inhibited root gravitropism. These results indicate that the generation of ROS plays a role in root gravitropism.
Food availability and choice in rural Scotland: the impact of “place”
Authors: Skerratt Sarah
Published: July 2002

This paper comprises an examination of a connection between geographical remoteness and isolation, and food availability and choice amongst the local populations. The paper focuses on three locations within the Highlands and Islands: the Western Isles, Upper Loch Torridon, and the rural areas surrounding Thurso. Following an outline of the research projects and their methodology, selected results are presented, focusing on the contemporary diet, and food choice and availability. The paper concludes with a discussion concerning the extent to which the data from the three rural case studies support a relationship between “place” and food choice, and makes recommendations concerning future policy and research issues.
The state of cooking in England: the relationship of cooking skills to food choice
Authors: Caraher Martin , Dixon Paul , Lang Tim , Carr‐Hill Roy
Published: July 2002

This article uses data from the 1993 Health and Lifestyles Survey of England to present findings on how, why and when people use cooking skills; where and from whom people learn these skills. The implications for policy are explored. The survey data suggests that socio‐economic status and education are associated with the sources of people’s knowledge about cooking. The first or prime source of learning about cooking skills was reported to be mothers; cooking classes in school were cited as the next most important by the majority of correspondents, with some class and educational variations. The importance of mothers as sources of information on cooking skills is observed in all social classes. What emerges is a population unsure of specific cooking techniques and lacking in confidence to apply techniques and cook certain foods. Women still bear the burden of cooking for the household, with four out of every five women respondents cooking on most or every day, compared with one in five men. This may be related to the large number of men who claim to have no cooking skills (one in five).
Public perceptions about microbiological hazards in food
Authors: Miles Susan , Braxton Denise S. , Frewer Lynn J.
Published: July 2002

A marked increase in the incidence of microbial food poisoning parallels increasing scientific and public concern about microbiological hazards. This literature review highlights the important pathogens involved in the increase and issues salient to developing effective risk‐benefit communication with the public about microbial food poisoning. Research into public perceptions of microbiological food hazards is reviewed, together with public attitudes towards one of the technologies that could combat food poisoning: food irradiation. Suggestions for reducing the incidence of microbial food poisoning through effective communication strategies are provided.
Emotional intelligence – training people to be affective so they can be effective
Authors: Bagshaw Mike
Published: July 2002

When people in the workplace do not act with emotional intelligence the costs can be great. Low morale, bitter conflict, and stress all limit business effectiveness. There is also the financial cost of litigation when people complain of being bullied, intimidated, and exploited. Emotional intelligence also contributes in a positive business enhancing way, improving teamworking, customer service and the managing of diversity. Fortunately this critical personal resource can be improved through appropriate coaching and training.
Long hours at work: are they dangerous and do people consent to them?
Authors: Savery Lawson K. , Luks J. Alan
Published: July 2002

This study examines the influence of perceived work‐related stress levels and levels of job satisfaction on work‐related injury/illnesses. Further, the influence of demographic data on these variables is also considered. The data were collected in a Federal Government study on Workplace Industrial Activities across Australia (AWIRS 95). It appears, from the data, that there is a significant relationship between low levels of job satisfaction and the reporting of work‐related injury/illnesses in the previous 12 months. This is also true for people who reported high levels of job stress. The data show that women seem to be more satisfied than their male colleagues and have fewer injuries and/or illnesses. One reason for the low level of injury/illness may be due to the occupations that men and women occupy. It seems that people who work in such occupations as labourers, plant and machine operators and tradespersons and apprentices are the most likely to have work‐related accidents and/or illnesses than other occupations and many of the people in the high injury incident occupations appear to be males. The study draws tentative conclusions on the influence of demographic data on levels of job satisfaction and job stress and the relationships with work‐related injury and/or illnesses.
Intelligent biosensors
Authors: Powner E.T. , Yalcinkaya F.
Published: July 2002

Discusses intelligent materials, intelligent material‐based sensors, their transducing methods, and different kinds of transducers used with smart material‐based sensors. Assumes that the future of intelligent sensors will almost totally depend on intelligent chemistry and intelligent instrumentation. Molecular recognition will widen the horizons of smart systems with the help of VLSI‐based design and fabrication. Discusses different sensor mechanisms, such as ENFETs, immunoFETs, ISFETs and chemFETs and takes a detailed look at potentiometric, amperometric and optical biosensors.
Achieving strategic facilities management through strong relationships
Authors: Barrett Peter
Published: July 2002

Facilities management tends to be technically orientated and reactive. However, the information revolution is having massive impacts in terms of where, when and how people work. As a consequence “facilities” are being propelled to centre stage as a strategic issue, even if they were not perceived as such before. To grasp this opportunity facilities managers need to engage in a balanced, coherent set of operational and strategic interactions and this paper sets out a generic model that identifies these. In addition, to address the strategic issues strong relationships with key players need to be progressively established so that tacit knowledge can flow creatively. This has profound implications for the required mindset, knowledge and skills of facilities managers.
An evaluation of programmes for staff motivation in NHS and hotel ancillary staff
Authors: Smith Louise
Published: July 2002

The study was concerned with investigating the most effective means of motivating low waged workers in the UK’s private and public sectors. Levels of job satisfaction, as an indicator of work motivation, were compared between ancillary staff in the National Health Service (NHS) and the hotel and leisure industry, and correlated with the staff‐centred programmes introduced in organisations for addressing the issue of staff motivation. Through empirical study no association was found between financial incentives and job satisfaction or staff motivation, and a positive correlation was found between staff‐centred programmes and staff satisfaction and staff motivation, which has implications for the working practices for these workers in the NHS. These findings are placed in a theoretical context.
The impact of monochronic and Type A behavior patterns on research productivity and stress
Authors: Frei Richard L. , Racicot Bernadette , Travagline Angela
Published: July 2002

To examine the relationship between monochronic work behavior (behavior that minimizes interruptions on the job) and Type A behavior, 147 faculty members of a midsized private university responded to a set of questionnaires which measured monochronic work behaviors, Type A behavior, job‐induced stress, research productivity, and number of working projects. Type A behavior was significantly and positively correlated with monochronic behaviors – in other words, Type As were more likely to use behavioral strategies that reduced polychronic thought. Type A and monochronic behaviors were also significantly correlated with job‐induced stress and number of publications. Contrary to the hypothesis, Type A and monochronic behaviors were also positively and significantly correlated with number of working projects.
Management development issues for owners/managers of micro‐enterprises
Authors: O’Dwyer Michèle , Ryan Eamon
Published: July 2002

Management development has traditionally been perceived as being the domain of large rather than micro‐enterprises, with developmental issues normally being addressed by means of educational interventions.However, the challenges and obstacles for growth facing these micro‐enterprises (businesses employing ten people or fewer) differ significantly from those of a larger organisation. Reports on the current provision for management development as it relates to micro‐enterprises, and the perception of owners/managers in Ireland of the role of management development in the running of their companies. The objective of the research was to establish the nature and content of training and development interventions required by the owners/managers of micro‐enterprises. Preliminary research and findings indicated the need for a new approach towards the design of management development programmes for micro‐entrepreneurs. Taking into account the perceptions and preferences of owners/managers it is clear that a new approach to the design and delivery of management development programmes for micro‐entrepreneurs is needed. This new approach has implications for trainers as it includes changes not only in the content but also in the timing, location and delivery mechanism of programmes. The research results suggest a model for the formulation ofamanagement development training strategy for owners/managers of micro‐enterprises. Outlines design specifications for a management development programme for owners/managers, based on the model developed from the research findings.
Abduction in language interpretation and law making
Authors: Andreewsky Evelyne , Bourcier Danièle
Published: July 2002

The complexity of any given cognitive phenomenon, such as “scientific discovery”, “technical expertise”, or “natural language understanding”, requires a multidisciplinary approach. Presents, within the framework of such an approach, some visible evidences of how these very different phenomena are closely rooted in the same highly inventive cognitive process, abduction. These evidences will be provided out of examples from both everyday language interpretation and law making expertise.
No‐interval coherently phased product development model for apparel
Authors: May‐Plumlee Traci , Little Trevor J.
Published: July 2002

Existing literature clearly documents the importance of new product development to success of a manufacturing firm. Many examples of generic models of the process, including sequential, concurrent, and multiple convergent models, can be found. However, these models are of insufficient detail to provide an adequate foundation for redesigning the apparel product development process. The no‐interval coherently phased product development (NICPPD) model for apparel introduced in this paper documents apparel product development as a six phase process with multiple convergent points and coherently phased divisions. The NICPPD model provides for developing both product lines and individual products, developing seasonal lines and multiple seasons annually, and use of alternative development strategies including original design development, knock‐offs or take‐offs, and modification of existing products. Multiple applications for use of the NICPPD model by both researchers and practitioners in examining and improving the apparel product development process are identified.
Creating Empowered Schools
Authors: Myrick Short Paula , Greer John T. , Melvin William M.
Published: July 2002

Sets out to understand how schools participating in a project to create
empowered schools defined empowerment, how they structured the change
process and how the school culture changed as a result of the effort to
empower participants. Results of the change effort indicate that the
participating schools could be grouped into three categories regarding
their success in substantially changing the school culture in support of
the empowerment concept, creating structures that build participant
empowerment and in principal actions that facilitate the development of
empowered participants. The three types of school were the opportunity
school, the shifter school and the no‐go school. From these types of
school, presents five themes for understanding school change.
Wisdom gained, wisdom given: instituting PBL in a Chinese culture
Authors: Walker Allan , Bridges Edwin , Chan Benjamin
Published: July 2002

Describes and analyses an initial attempt to introduce problem‐based learning (PBL) into a Chinese cultural setting. Discusses some of the tensions between the philosophy of PBL and the culture in which the authors used this innovative approach to leadership education. Further describes the strategies which the authors employed to address these underlying tensions and the reactions of the students to their first encounter with PBL. Examines possible cultural influences on the behaviour patterns the authors observed while the students attempted to solve the problem presented in the problem‐based learning materials. Whether these behaviours facilitate or hinder task accomplishment and group productivity remains an important area for further study.