bluuebunny/crossref_metadata_2025 huggingface dataset:
The EXCESS MICROSPOROCYTES1 gene encodes a putative leucine-rich repeat receptor protein kinase that controls somatic and reproductive cell fates in the Arabidopsis anther
Authors: Zhao Da-Zhong , Wang Guan-Fang , Speal Brooke , Ma Hong
Published: October 2002

Cell differentiation is essential for the development of multicellular organisms. In flowering plants, the haploid male gametophytes (pollen grains) are generated in the anther from reproductive cells called microsporocytes. Several types of somatic cells ensure successful pollen development, and thus reproduction. However, it is not clear what genes regulate the differentiation of these diverse, highly specialized cells in the anther. We report here the isolation and characterization of a novel Arabidopsis thaliana male sterile mutant, excess microsporocytes1(ems1), that produces excess microsporocytes, lacks tapetal cells, and abnormally maintains middle layer cells. Although the meiotic nuclear division in the ems1 mutant is normal, the microsporocytes do not undergo cytokinesis, resulting in failed microsporogenesis and male sterility. The EMS1 gene encodes a putative leucine-rich repeat receptor protein kinase (LRR-RPK), and its expression is associated with the differentiation of the microsporocytes and tapetal cells, suggesting that EMS1mediates signals that control the fate of reproductive cells and their contiguous somatic cells.
Pattern and Timing of Gene Duplication in Animal Genomes
Authors: Friedman Robert , Hughes Austin L.
Published: October 2002

Duplication of genes, giving rise to multigene families, has been a characteristic feature of the evolution of eukaryotic genomes. In the case of vertebrates, it has been proposed that an increase in gene number resulted from two rounds of duplication of the entire genome by polyploidization (the 2R hypothesis). In the most extensive test to date of this hypothesis, we compared gene numbers in homologous families and conducted phylogenetic analyses of gene families with two to eight members in the complete genomes ofCaenorhabditis elegansandDrosophila melanogasterand the available portion of the human genome. Although the human genome showed a higher proportion of recent gene duplications than the other animal genomes, the proportion of duplications after the deuterostome–protostome split was constant across families, with no peak of such duplications in four-member families, contrary to the expectation of the 2R hypothesis. A substantial majority (70.9%) of human four-member families and four-member clusters in larger families showed topologies inconsistent with two rounds of polyploidization in vertebrates.
B-ZIP Proteins Encoded by the Drosophila Genome: Evaluation of Potential Dimerization Partners
Authors: Fassler Jan , Landsman David , Acharya Asha , Moll Jonathan R. , Bonovich Maria , Vinson Charles
Published: October 2002

The basic region-leucine zipper (B-ZIP) (bZIP) protein motif dimerizes to bind specific DNA sequences. We have identified 27 B-ZIP proteins in the recently sequenced Drosophila melanogaster genome. The dimerization specificity of these 27 B-ZIP proteins was evaluated using two structural criteria: (1) the presence of attractive or repulsive interhelical g↔e‘ electrostatic interactions and (2) the presence of polar or charged amino acids in the ‘a’ and ‘d’ positions of the hydrophobic interface. None of the B-ZIP proteins contain only aliphatic amino acids in the‘a’ and ‘d’ position. Only six of theDrosophila B-ZIP proteins contain a “canonical” hydrophobic interface like the yeast GCN4, and the mammalian JUN, ATF2, CREB, C/EBP, and PAR leucine zippers, characterized by asparagine in the second ‘a’ position. Twelve leucine zippers contain polar amino acids in the first, third, and fourth ‘a’ positions. Circular dichroism spectroscopy, used to monitor thermal denaturations of a heterodimerizing leucine zipper system containing either valine (V) or asparagine (N) in the ‘a’ position, indicates that the V–N interaction is 2.3 kcal/mole less stable than an N–N interaction and 5.3 kcal/mole less stable than a V–V interaction. Thus, we propose that the presence of polar amino acids in novel positions of the ‘a’ position of Drosophila B-ZIP proteins has led to leucine zippers that homodimerize rather than heterodimerize.
Predicting Protein Cellular Localization Using a Domain Projection Method
Authors: Mott Richard , Schultz Jörg , Bork Peer , Ponting Chris P.
Published: October 2002

We investigate the co-occurrence of domain families in eukaryotic proteins to predict protein cellular localization. Approximately half (300) of SMART domains form a “small-world network”, linked by no more than seven degrees of separation. Projection of the domains onto two-dimensional space reveals three clusters that correspond to cellular compartments containing secreted, cytoplasmic, and nuclear proteins. The projection method takes into account the existence of “bridging” domains, that is, instances where two domains might not occur with each other but frequently co-occur with a third domain; in such circumstances the domains are neighbors in the projection. While the majority of domains are specific to a compartment (“locale”), and hence may be used to localize any protein that contains such a domain, a small subset of domains either are present in multiple locales or occur in transmembrane proteins. Comparison with previously annotated proteins shows that SMART domain data used with this approach can predict, with 92% accuracy, the localizations of 23% of eukaryotic proteins. The coverage and accuracy will increase with improvements in domain database coverage. This method is complementary to approaches that use amino-acid composition or identify sorting sequences; these methods may be combined to further enhance prediction accuracy.
Extracellular Signal-Regulated Kinase Activity in the Entorhinal Cortex Is Necessary for Long-Term Spatial Memory
Authors: Hebert April E. , Dash Pramod K.
Published: October 2002

Lesion studies have provided evidence that the entorhinal cortex (EC) participates in spatial memory. However, the molecular cascades that underlie memory-associated changes in the EC and its specific role in spatial memory, however, have not been clearly delineated. Recently, it has been shown that activation of extracellular signal-regulated kinase (Erk, a mitogen-activated protein kinase family member) in the dorsal hippocampus is necessary for spatial memory. To examine whether similar mechanisms are used for spatial memory storage in the EC, Erk activity was inhibited after training in the Morris water maze. Bilateral infusion of the mitogen-activated protein kinase kinase inhibitor PD098059 into the EC immediately after training resulted in a memory deficit observed during a retention test performed 48 h later. This deficit was abolished with pretraining in a different water maze in which animals were able to learn the general task requirements and the appropriate search strategies. The absence of a deficit indicates that Erk activity in the EC may be involved in storing the task requirements or the search strategies. The findings presented in this article are consistent with the idea that the EC is involved in spatial memory and indicate that Erk activity is necessary for memory consolidation in this structure.
Memories in Drosophila Heat-box Learning
Authors: Putz Gabriele , Heisenberg Martin
Published: October 2002

Learning and memory processes of operant conditioning in the heat-box are analyzed. In a search for conditioning parameters leading to high retention scores, intermittent training is shown to give better results than those of continuous training. Immediate retention tests contain two memory components, a spatial preference for one side of the chamber and a “stay-where-you-are-effect.” Intermittent training strengthens the latter. In the second part, memory dynamics is investigated. Flies are trained in one chamber and tested in a second one after a brief reminder training. With this direct transfer, memory scores reflect an associative learning process in the first chamber. To investigate memory retention after extended time periods, indirect transfer experiments are performed. The fly is transferred to a different environment between training and test phases. With this procedure, an aftereffect of the training can still be observed 2 h later. Surprisingly, exposure to the chamber without conditioning also leads to a memory effect in the indirect transfer experiment. This exposure effect reveals a dispositional change that facilitates operant learning during the reminder training. The various memory effects are independent of the mushroom bodies.
Overexpression ofhAPPsweImpairs Rewarded Alternation and Contextual Fear Conditioning in a Transgenic Mouse Model of Alzheimer's Disease
Authors: Corcoran Kevin A. , Lu Ye , Turner R. Scott , Maren Stephen
Published: October 2002

One of the hallmarks of the pathology in Alzheimer's disease is the deposition of amyloid plaques throughout the brain, especially within the hippocampus and amygdala. Transgenic mice that overexpress the Swedish mutation of human amyloid precursor protein (hAPPswe;Tg2576) show age-dependent memory deficits in hippocampus-dependent learning tasks. However, the performance of aged Tg2576 mice in amygdala-dependent learning tasks has not been thoroughly assessed. We trained young (2–4 mo) and old (16–18 mo) Tg2576 and wild-type mice in a T-maze alternation task (hippocampus-dependent) and a Pavlovian fear-conditioning task (amygdala- and hippocampus-dependent). As previously reported, old Tg2576 mice showed impaired acquisition of rewarded alternation; none of these mice reached the criterion of at least five out of six correct responses over three consecutive days. In contrast, old Tg2576 mice showed normal levels of conditional freezing to an auditory conditional stimulus (CS) and acquired a contextual discrimination normally. However, when the salience of the fear-conditioning context was decreased, old (12–14 mo) Tg2576 mice were impaired at acquiring fear to the conditioning context, but not to the tone CS. Histological examination of a subset of the mice verified the existence of amyloid plaques in the cortex, hippocampus, and amygdala of old, but not young, Tg2576 mice. Hence, learning and memory deficits in old Tg2576 mice are limited to hippocampus-dependent tasks, despite widespread amyloid deposition in cortex, hippocampus, and amygdala.
Recognition Memory for Single Items and for Associations Is Similarly Impaired Following Damage to the Hippocampal Region
Authors: Stark Craig E.L. , Bayley Peter J. , Squire Larry R.
Published: October 2002

The formation of new associations between items is critical for establishing episodic memories. It has been suggested that the hippocampus is essential for creating such associations but is not involved, or is much less involved, in memory for single items. In Experiment 1, we tested controls and amnesic patients with bilateral lesions thought to be limited primarily to the hippocampal region in both single-item and associative recognition memory tasks. In the single-item task, a conventional recognition memory task was administered in which participants studied either houses or faces and were tested for their ability to recognize the individual items. In the associative task, participants studied paired pictures of houses and faces with instructions that encouraged associating the two stimuli, and were tested for their ability to recognize the specific pairings that were presented at study. Like the controls, the amnesic patients performed more poorly on the associative task. Relative to the controls, the amnesic patients were impaired to a similar extent on the single-item and associative tasks. In Experiment 2, the performance of the amnesic patients was improved by increasing the number of presentations of the study lists (eight presentations instead of one). On both the single-item and associative tests, the performance of the amnesic patients after eight presentations was now identical to the performance of the controls who had been given only one presentation of the study list. Thus, the associative condition was not disproportionally difficult for the amnesic patients. These results are consistent with the idea that the hippocampus is similarly involved in single-item and associative memory.
A Thapsigargin-Sensitive Ca2+ Pump Is Present in the Pea Golgi Apparatus Membrane
Authors: Ordenes Viviana R. , Reyes Francisca C. , Wolff Daniel , Orellana Ariel
Published: October 2002

The Golgi apparatus behaves as a bona fide Ca2+ store in animal cells and yeast (Saccharomyces cerevisiae); however, it is not known whether this organelle plays a similar role in plant cells. In this work, we investigated the presence of an active Ca2+accumulation mechanism in the plant cell Golgi apparatus. Toward this end, we measured Ca2+ uptake in subcellular fractions isolated from the elongating zone of etiolated pea (Pisum sativum) epicotyls. Separation of organelles using sucrose gradients showed a strong correlation between the distribution of an ATP-dependent Ca2+ uptake activity and the Golgi apparatus marker enzyme, xyloglucan-fucosyltransferase. The kinetic parameters obtained for this activity were: the rate of maximum Ca2+ uptake of 2.5 nmol mg min−1 and an apparent K  m for Ca2+ of 209 nm. The ATP-dependent Ca2+ uptake was strongly inhibited by vanadate (inhibitor concentration causing 50% inhibition [I50] = 126 μm) and cyclopiazonic acid (I50 = 0.36 nmol mg protein−1) and was not stimulated by calmodulin (1 μm). Addition of Cd2+ and Cu2+ at nanomolar concentration inhibited the Ca2+ uptake, whereas Mn2+, Fe2+, and Co2+ had no significant effect. Interestingly, the active calcium uptake was inhibited by thapsigargin (apparent I50 = 88 nm), a well-known inhibitor of the endoplasmic reticulum and Golgi sarco-endoplasmic reticulum Ca2+ ATPase from mammalian cells. A thapsigargin-sensitive Ca2+ uptake activity was also detected in a cauliflower (Brassica oleracea) Golgi-enriched fraction, suggesting that other plants may also possess thapsigargin-sensitive Golgi Ca2+ pumps. To our knowledge, this is the first report of a plant Ca2+pump activity that shows sensitivity to low concentrations of thapsigargin.
Sensitivity of Photosynthesis in a C4 Plant, Maize, to Heat Stress
Authors: Crafts-Brandner Steven J. , Salvucci Michael E.
Published: October 2002

Our objective was to determine the sensitivity of components of the photosynthetic apparatus of maize (Zea mays), a C4 plant, to high temperature stress. Net photosynthesis (Pn) was inhibited at leaf temperatures above 38°C, and the inhibition was much more severe when the temperature was increased rapidly rather than gradually. Transpiration rate increased progressively with leaf temperature, indicating that inhibition was not associated with stomatal closure. Nonphotochemical fluorescence quenching (qN) increased at leaf temperatures above 30°C, indicating increased thylakoid energization even at temperatures that did not inhibit Pn. Compared with CO2 assimilation, the maximum quantum yield of photosystem II (F  v/F  m) was relatively insensitive to leaf temperatures up to 45°C. The activation state of phosphoenolpyruvate carboxylase decreased marginally at leaf temperatures above 40°C, and the activity of pyruvate phosphate dikinase was insensitive to temperature up to 45°C. The activation state of Rubisco decreased at temperatures exceeding 32.5°C, with nearly complete inactivation at 45°C. Levels of 3-phosphoglyceric acid and ribulose-1,5-bisphosphate decreased and increased, respectively, as leaf temperature increased, consistent with the decrease in Rubisco activation. When leaf temperature was increased gradually, Rubisco activation acclimated in a similar manner as Pn, and acclimation was associated with the expression of a new activase polypeptide. Rates of Pn calculated solely from the kinetics of Rubisco were remarkably similar to measured rates if the calculation included adjustment for temperature effects on Rubisco activation. We conclude that inactivation of Rubisco was the primary constraint on the rate of Pn of maize leaves as leaf temperature increased above 30°C.
In Vivo and in Vitro Phosphorylation of Membrane and Soluble Forms of Soybean Nodule Sucrose Synthase
Authors: Komina Olga , Zhou You , Sarath Gautam , Chollet Raymond
Published: October 2002

Sucrose synthase (SS) is a known phosphoserine (SerP)-containing enzyme in a variety of plant “sink” organs, including legume root nodules, where it is phosphorylated primarily at Ser-11. Using immunofluorescence confocal microscopy, we documented that part of the total SS (nodulin-100) pool in mature soybean (Glycine max) nodules is apparently associated with the plasma membrane in situ, and we report that this association is very “tight,” as evidenced by a variety of chemical and enzymatic pretreatments of the isolated microsomal fraction. To investigate the in situ and in planta phosphorylation state of the membrane (m) and soluble (s) forms of nodule SS, three complementary approaches were used. First, excised nodules were radiolabeled in situ with [32P]Pi for subsequent analysis of phosphorylated m- and s-SS; second, immunopurified s- and m-SS were used as substrate in “on-bead” assays of phosphorylation by nodule Ca2+-dependent protein kinase; and third, SS-Ser-11(P) phosphopeptide-specific antibodies were developed and used. The collective results provide convincing evidence that microsomal nodulin-100 is phosphorylated in mature nodules, and that it is hypophosphorylated relative to s-SS (on an equivalent SS protein basis) in attached, unstressed nodules. Moreover, the immunological data and related phosphopeptide mapping analyses indicate that a homologous N-terminal seryl-phosphorylation domain and site reside in microsomal nodulin-100. We also observed that mild, short-term inorganic nitrogen and salt stresses have a significant negative impact on the content and N-terminal phosphorylation state of nodule m- and s-SS, with the former being the more sensitive of the two SS forms.
Redox Regulation of Arabidopsis 3-Deoxy-d-arabino-Heptulosonate 7-Phosphate Synthase
Authors: Entus Robert , Poling Michael , Herrmann Klaus M.
Published: October 2002

The cDNA for 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase of Arabidopsis encodes a polypeptide with an amino-terminal signal sequence for plastid import. A cDNA fragment encoding the processed form of the enzyme was expressed in Escherichia coli. The resulting protein was purified to electrophoretic homogeneity. The enzyme requires Mn2+ and reduced thioredoxin (TRX) for activity. Spinach (Spinacia oleracea) TRX f has an apparent dissociation constant for the enzyme of about 0.2 μm. The corresponding constant for TRX m is orders of magnitude higher. In the absence of TRX, dithiothreitol partially activates the enzyme. Upon alkylation of the enzyme with iodoacetamide, the dependence on a reducing agent is lost. These results indicate that the first enzyme in the shikimate pathway of Arabidopsis appears to be regulated by the ferredoxin/TRX redox control of the chloroplast.
The out of phase 1 Mutant Defines a Role for PHYB in Circadian Phase Control in Arabidopsis
Authors: Salomé Patrice A. , Michael Todd P. , Kearns Ellen V. , Fett-Neto Arthur G. , Sharrock Robert A. , McClung C. Robertson
Published: October 2002

Arabidopsis displays circadian rhythms in stomatal aperture, stomatal conductance, and CO2 assimilation, each of which peaks around the middle of the day. The rhythmic opening and closing of stomata confers a rhythm in sensitivity and resistance, respectively, to the toxic gas sulfur dioxide. Using this physiological assay as a basis for a mutant screen, we isolated mutants with defects in circadian timing. Here, we characterize one mutant, out of phase 1 (oop1), with the circadian phenotype of altered phase. That is, the timing of the peak (acrophase) of multiple circadian rhythms (leaf movement, CO2 assimilation, andLIGHT-HARVESTING CHLOROPHYLL a/b-BINDING PROTEINtranscription) is early with respect to wild type, although all circadian rhythms retain normal period length. This is the first such mutant to be characterized in Arabidopsis. oop1 also displays a strong photoperception defect in red light characteristic ofphytochrome B (phyB) mutants. Theoop1 mutation is a nonsense mutation ofPHYB that results in a truncated protein of 904 amino acids. The defect in circadian phasing is seen in seedlings entrained by a light-dark cycle but not in seedlings entrained by a temperature cycle. Thus, PHYB contributes light information critical for proper determination of circadian phase.
Seasonal Changes of Plasma Membrane H+-ATPase and Endogenous Ion Current during Cambial Growth in Poplar Plants
Authors: Arend Matthias , Weisenseel Manfred H. , Brummer Maria , Osswald Wolfgang , Fromm Jörg H.
Published: October 2002

The plasma membrane H+-ATPase (PM H+-ATPase), potassium ions, and endogenous ion currents might play a fundamental role in the physiology of cambial growth. Seasonal changes of these parameters were studied in twigs ofPopulus nigra and Populus trichocarpa. Monoclonal and polyclonal antibodies against the PM H+-ATPase, x-ray analysis for K+ localization and a vibrating electrode for measurement of endogenous ion currents were used as probes. In dormant plants during autumn and winter, only a slight immunoreactivity against the PM H+-ATPase was found in cross sections and tissue homogenates, K+ was distributed evenly, and the density of endogenous current was low. In spring during cambial growth, strong immunoreactivity against a PM H+-ATPase was observed in cambial cells and expanding xylem cells using the monoclonal antibody 46 E5 B11 F6 for fluorescence microscopy and transmission electron microscopy. At the same time, K+ accumulated in cells of the cambial region, and strong endogenous current was measured in the cambial and immature xylem zone. Addition of auxin to dormant twigs induced the formation of this PM H+-ATPase in the dormant cambial region within a few days and an increase in density of endogenous current in shoot cuttings within a few hours. The increase in PM H+-ATPase abundance and in current density by auxin indicates that auxin mediates a rise in number and activity of an H+-ATPase in the plasma membrane of cambial cells and their derivatives. This PM H+-ATPase generates the necessary H+-gradient (proton-motive force) for the uptake of K+ and nutrients into cambial and expanding xylem cells.
AtCOX17, an Arabidopsis Homolog of the Yeast Copper Chaperone COX17
Authors: Balandin Teresa , Castresana Carmen
Published: October 2002

We have identified a new plant gene, AtCOX17, encoding a protein that shares sequence similarity to COX17, a Cu-binding protein from yeast (Saccharomyces cerevisiae) and vertebrates that mediates the delivery of Cu to the mitochondria for the assembly of a functional cytochrome oxidase complex. The newly characterized Arabidopsis protein has six Cys residues at positions corresponding to those known to coordinate Cu binding in the yeast homolog. Moreover, we show that the Arabidopsis COX17cDNA complements a COX17 mutant of yeast restoring the respiratory deficiency associated with that mutation. These two lines of evidence indicate that the plant protein identified here is a functional equivalent of yeast COX17 and might serve as a Cu delivery protein for the plant mitochondria. COX17 was identified by investigating the hypersensitive response-like necrotic response provoked in tobacco (Nicotiana tabacum) leaves after harpin inoculation. AtCOX17 expression was activated by high concentrations of Cu, bacterial inoculation, salicylic acid treatment, and treatments that generated NO and hydrogen peroxide. All of the conditions inducing COX17 are known to inhibit mitochondrial respiration and to produce an increase of reactive oxygen species, suggesting that gene induction occurs in response to stress situations that interfere with mitochondrial function.
Steroleosin, a Sterol-Binding Dehydrogenase in Seed Oil Bodies
Authors: Lin Li-Jen , Tai Sorgan S.K. , Peng Chi-Chung , Tzen Jason T.C.
Published: October 2002

Besides abundant oleosin, three minor proteins, Sop 1, 2, and 3, are present in sesame (Sesamum indicum) oil bodies. The gene encoding Sop1, named caleosin for its calcium-binding capacity, has recently been cloned. In this study, Sop2 gene was obtained by immunoscreening, and it was subsequently confirmed by amino acid partial sequencing and immunological recognition of its overexpressed protein in Escherichia coli. Immunological cross recognition implies that Sop2 exists in seed oil bodies of diverse species. Along with oleosin and caleosin genes, Sop2 gene was transcribed in maturing seeds where oil bodies are actively assembled. Sequence analysis reveals that Sop2, tentatively named steroleosin, possesses a hydrophobic anchoring segment preceding a soluble domain homologous to sterol-binding dehydrogenases/reductases involved in signal transduction in diverse organisms. Three-dimensional structure of the soluble domain was predicted via homology modeling. The structure forms a seven-stranded parallel β-sheet with the active site, S-(12X)-Y-(3X)-K, between an NADPH and a sterol-binding subdomain. Sterol-coupling dehydrogenase activity was demonstrated in the overexpressed soluble domain of steroleosin as well as in purified oil bodies. Southern hybridization suggests that one steroleosin gene and certain homologous genes may be present in the sesame genome. Comparably, eight hypothetical steroleosin-like proteins are present in the Arabidopsis genome with a conserved NADPH-binding subdomain, but a divergent sterol-binding subdomain. It is indicated that steroleosin-like proteins may represent a class of dehydrogenases/reductases that are involved in plant signal transduction regulated by various sterols.
A T-DNA Insertion Knockout of the Bifunctional Lysine-Ketoglutarate Reductase/Saccharopine Dehydrogenase Gene Elevates Lysine Levels in Arabidopsis Seeds
Authors: Zhu Xiaohong , Tang Guiliang , Granier Fabienne , Bouchez David , Galili Gad
Published: October 2002

Plants possess both anabolic and catabolic pathways for the essential amino acid lysine (Lys). However, although the biosynthetic pathway was clearly shown to regulate Lys accumulation in plants, the functional significance of Lys catabolism has not been experimentally elucidated. To address this issue, we have isolated an Arabidopsis knockout mutant with a T-DNA inserted into exon 13 of the gene encoding Lys ketoglutarate reductase/saccharopine dehydrogenase. This bifunctional enzyme controls the first two steps of Lys catabolism. The phenotype of the LKR/SDH knockout was indistinguishable from wild-type plants under normal growth conditions, suggesting that Lys catabolism is not an essential pathway under standard growth conditions. However, mature seeds of the knockout mutant over-accumulated Lys compared with wild-type plants. This report provides the first direct evidence for the functional significance of Lys catabolism in regulating Lys accumulation in seeds. Such a knockout mutant may also provide new perspectives to improve the level of the essential amino acid Lys in plant seeds.
Whole-Plant Gas Exchange and Reductive Biosynthesis in White Lupin
Authors: Cen Yan-Ping , Turpin David H. , Layzell David B.
Published: October 2002

Simultaneous measurements of CO2 (CER) and O2 (OER) exchange in roots and shoots of vegetative white lupin (Lupinus albus) were used to calculate the flow of reducing power to the synthesis of biomass that was more reduced per unit of carbon than carbohydrate. On a whole-plant basis, the diverted reductant utilization rate (DRUR which is: 4 × [CER + OER]) of shoot tissue was consistently higher than that of roots, and values obtained in the light were greater than those in the dark. An analysis of the biomass being synthesized over a 24-h period provided an estimate of whole-plant DRUR (3.5 mmol e−plant−1 d−1), which was similar to that measured by gas exchange (3.2 mmol e− plant−1d−1). Given that nitrate reduction to ammonia makes up about 74% of whole-plant DRUR, root nitrate reduction in white lupin was estimated to account for less than 43% of whole-plant nitrate reduction. The approach developed here should offer a powerful tool for the noninvasive study of metabolic regulation in intact plants or plant organs.
Arabidopsis Transcriptome Profiling Indicates That Multiple Regulatory Pathways Are Activated during Cold Acclimation in Addition to the CBF Cold Response Pathway[W]
Authors: Fowler Sarah , Thomashow Michael F.
Published: October 2002

Many plants, including Arabidopsis, increase in freezing tolerance in response to low, nonfreezing temperatures, a phenomenon known as cold acclimation. Previous studies established that cold acclimation involves rapid expression of the CBF transcriptional activators (also known as DREB1 proteins) in response to low temperature followed by induction of the CBF regulon (CBF-targeted genes), which contributes to an increase in freezing tolerance. Here, we present the results of transcriptome-profiling experiments indicating the existence of multiple low-temperature regulatory pathways in addition to the CBF cold response pathway. The transcript levels of ∼8000 genes were determined at multiple times after plants were transferred from warm to cold temperature and in warm-grown plants that constitutively expressed CBF1, CBF2, or CBF3. A total of 306 genes were identified as being cold responsive, with transcripts for 218 genes increasing and those for 88 genes decreasing threefold or more at one or more time points during the 7-day experiment. These results indicate that extensive downregulation of gene expression occurs during cold acclimation. Of the cold-responsive genes, 48 encode known or putative transcription factors. Two of these, RAP2.1 and RAP2.6, were activated by CBF expression and thus presumably control subregulons of the CBF regulon. Transcriptome comparisons indicated that only 12% of the cold-responsive genes are certain members of the CBF regulon. Moreover, at least 28% of the cold-responsive genes were not regulated by the CBF transcription factors, including 15 encoding known or putative transcription factors, indicating that these cold-responsive genes are members of different low-temperature regulons. Significantly, CBF expression at warm temperatures repressed the expression of eight genes that also were downregulated by low temperature, indicating that in addition to gene induction, gene repression is likely to play an integral role in cold acclimation.
Initial spare parts supply of an orbital system
Authors: Pérès François , Grenouilleau Jean‐Christophe
Published: October 2002

This article presents a method of management of the initial spare parts supply. This generic problem is of particular interest in certain systems in which the difficulty of accessibility or the life cycle duration constitute risks tied to the possible depletion of the spare parts stock. In this paper we consider the spatial context. After having commented on the particularities of the management of the spare parts supply of a space station, we propose a method based on the minimization of the risk of postponement of a maintenance operation. Finally, an application to the Columbus laboratory of the International Space Station is presented.
The practice of distance librarianship in Africa
Authors: Oladokun Olugbade S.
Published: October 2002

If taking knowledge and training to the maginalised, isolated, underprivileged and the unreachable is the goal of distance education, then Africa is qualified to be the home of distance education. The paper talks about the inadequacy of education inherited in the continent at independence, and the yearning of various governments to improve educationally the lot of people, which gave birth to the obvious option of distance learning. Unfortunately the economic downturn affected proper funding of education and provision of resources including provision of library facilities. The corollary of this is that except for a handful of university libraries, library support service to distance learners is almost non‐existent. The scenario is painted of the practice in some universities where a distance learning mode is adopted. The paper concludes with some suggestions on what could be done to alleviate the agony of distance learners in the continent.
Beyond global marketing and the globalization of marketing activities
Authors: Svensson Göran
Published: October 2002

The topic of this article is the term “global marketing” and the phenomenon of the “globalization” of marketing activities. Global marketing is a theoretical concept that in a managerial context is hardly applicable. Global marketing and the globalization of marketing activities have become a cliché among marketing scholars and marketing practitioners. Also introduced and discussed is the concept “glocal marketing” to fill the gap or vacuum between the theoretical concept of global marketing and the empirical phenomenon of the globalization of marketing activities applied both by marketing scholars and by marketing practitioners.
Theorising path‐dependency: how does history come to matter in organisations?
Authors: Greener Ian
Published: October 2002

Contends that path‐dependency provides an accurate, but under‐theorised description of organisational behaviour. By incorporating insights from actor‐network theory, we can better understand the processes by which organisations become “locked‐in” to behaviour patterns, but also how we might begin to break free from them. It seems that we must pay greater attention to the role of durable materials in networks, and to the strategies of simplification employed within organisations to deal with the complexity that surrounds them. In order to understand path‐dependency we must also look wider than traditional management theory towards a more semiotic understanding of organisational communication. All of these findings point to managers having to reconsider their role, especially with regard to the power that they may or may not hold, and to move towards an approach based more on the governance of their organisations than attempting to control every aspect under their jurisdiction. Concludes by providing some appropriate strategies through which this might be achieved.
Implementing the VTLS library management system at Tomsk State University Library: impact on management
Authors: Francis Simon
Published: October 2002

An account is given of the implications for management of the introduction of the VTLS automation system in Tomsk State University Library in Siberia, as part of a library modernisation project funded under the EU TEMPUS‐TACIS programme. The case study describes the changes brought about by the project, which included the creation of one of the first strategic development plans produced by a Russian university library and a considerable change in the attitudes of Tomsk State University Library staff. Examples are given of the effects of one of the first implementations of a full Western automation system covering all functional modules on the structure of the library.
Bismuth – the new ecologically green metal for modern lubricating engineering
Authors: Rohr Otto
Published: October 2002

Bismuth is relatively little known in general; however, it has been known since the fifteenth century in Germany and was called by Paracelsus “Bismutum”. With very similar properties to lead, it could be called the “twin brother of lead”, but bismuth is considered non‐toxic and used in cosmetics and pharmaceuticals. It is really a unique metal, considered as a metal within the periodic table of elements, but has more similarity to semimetals than to metals. Bismuth replaces the formerly and widely used lead in EP‐greases and EP‐lubricants giving better properties to them, even using down to half of the metal concentration. Bismuth has very high synergism to sulphur, the oldest known element. So, the combination of the oldest known element sulphur with the newest “green and ecologically clean” metal Bismuth – is actually the modern and metallic extreme pressure technology – that follows the formerly used, during many decades, sulphur‐lead‐technology – but being non‐toxic.
Assessing determinants of departmental innovation
Authors: Mohamed Mohamed A.K.
Published: October 2002

A framework from multiple theoretical perspectives was developed to examine the link between a set of organizational and group variables and the level of group innovation. Survey data were collected from a sample of 150 government divisions in the United Arab Emirates, representing various functional areas, and analyzed using multivariate methods. Results indicate that managerial attitude, decentralization, supervisory support, group satisfaction, diversity, committee membership, and management learning are significant predictors of group innovation. Implications of the results are discussed and suggestions for future research presented.
Management issues of consortia. Part two
Authors: Evans G. Edward
Published: October 2002

Defines terms associated with consortia – co‐ordination, co‐operation and collaboration – and identifies critical success factors for consortia. Provides four case studies based on the author’s personal experience indicating the reasons for the success or failure of these collaborative ventures. The outcomes are discussed and conclusions drawn. The evidence indicates that successful consortia require time to develop a high level of trust between partners and a willingness to contribute. Part one appeared inLibrary Management(2002), Vol. 23 No. 4/5.
Women in trade unions in India
Authors: Venkata Ratnam C.S. , Jain Harish C.
Published: October 2002

This paper on women in labour unions in India highlights the occupational segregation suffered by women in union structures. The authors explore and document the extent of female participation in trade unions in India. They suggest that less than 8 per cent of the 380 million workforce in India are unionized and women account for a very small fraction of trade union membership. They provide a number of reasons for the low female membership and participation in unions. In the occupations where women are organized, the incidence of union leadership among women varies considerably. On the positive side, the authors note that India has been a pioneer in organizing women in the informal sector such as workers’ cooperatives, self help groups such as Working Women’s Forum and Self Employed Women’s Association etc. In fact, they find that these unions are creating social unionism, thereby rewriting the meaning of trade unionism. The focus is on broad objectives of empowerment, development and fighting for their rights rather than the business unionism in North America (that is, focus on the bread and butter issues alone). The initiatives dictated by the Indian Constitution such as reservations or quotas for scheduled castes and scheduled tribes may have to be applied to labour unions and the private sector employers in the case of women in India. Policy makers and managers can learn a great deal from the theories discussed above.
A model for organization‐based 360 degree leadership assessment
Authors: Testa Mark R.
Published: October 2002

Success in the new economy is more dependent on successful relationships with internal and external stakeholders than ever before. The “business ecosystem” has created webs of interdependent relationships between organizations and their employees, suppliers, customers, and business partners. These relationships not only impact how firms add value to customers and create competitive advantage, but various internal processes as well. Unfortunately, these relationships often fail to capture their full potential due to misalignment between the organization and its stakeholders. This article presents a practical guide for organization‐based 360 degree leadership assessment, which should help organizations to identify gaps or “blind spots” with internal and external stakeholders. Borrowing from the multi‐rater feedback literature, a discussion of the steps in using the organization’s leadership as the focal point is provided. Self‐assessment on a series of organizational leadership dimensions is proposed, which is compared to evaluations by employees, customers, suppliers and business partners. The proposal should provide direction for practitioners seeking greater stakeholder feedback, and a foundation for further academic inquiry.
Structuring international service operations
Authors: Meijboom Bert , Houtepen Migon
Published: October 2002

The specific challenges with which companies pursuing international manufacturing strategies are faced, if their output also contains a service dimension, are addressed. A theoretical framework is proposed based on three virtually complementary perspectives by integrating international production, demand, and contemporary ICT‐based theory. Subsequently, an exploratory case study in a pure service environment is described that illustrates the value of the framework. The present study provides a starting‐point for further research in the international manufacturing sector. It is possible, for example, to apply the theoretical framework to case studies in internationally‐operating companies delivering a mix of goods and services. Moreover, the framework has proven to be useful in improving the European structure of the case company. This is a notable and promising side‐effect of the exploratory study, at least from a managerial point of view.
Culture and international management: a review
Authors: Miroshnik Victoria
Published: October 2002

This is a review article on the effectiveness of cross‐cultural managements of multinational companies. Analysis is based on the relationships between national and corporate culture and these corporate cultures vary across nations and how multinational companies can adopt the national differences.
Geomorphology and stone conservation: sandstone decay in Stoke‐on‐Trent
Authors: Wright Janet S.
Published: October 2002

Identifying stone decay forms is an essential first step in stone conservation. In this study a visually based geomorphological approach was used to provide a rapid assessment of the general weathering characteristics displayed by building sandstones in Stoke‐on‐Trent. Stone decay was found to be largely caused by the mechanical disruption of the sandstone and its occurrence was extremely variable in both space and time. The study demonstrates the close interrelationship between stone properties, environmental conditions, morphology of weathering features, and building characteristics. It is important that these close and dynamic interrelationships are recognised when seeking to explain or predict stone behaviour for management purposes.
The state of health and safety in the UK construction industry with a focus on plant operators
Authors: Edwards D.J. , Nicholas J.
Published: October 2002

Using statistics obtained from the Health and Safety Executive, compares accident rates occurring within the UK construction industry to the accident rates occurring within other industries; then assesses and discusses these. Results reveal that the construction industry is arguably the most hazardous industry and has consistently recorded a poor accident record. Off‐highway plant and equipment is a considerable contributor to the industry’s infamous record. Then assesses accidents relating to individual plant items and discusses the underlying reasons for such accidents. Part of the problem stems from poor mechanical design but in the majority of cases the operator is at fault. Training programmes and initiatives have previously attempted to address this problem but regrettably the Provision and Use of Work Equipment regulations do not enforce mandatory training and certification. Provides a potential solution to this problem through the use of psychometric test development. Hypothesizes such an approach as representing a useful technique for both improving the skills and competence of existing operatives, and aiding the selection process when hiring new operatives.
Internet users’ intention to purchase air travel online: an empirical investigation
Authors: Athiyaman Adee
Published: October 2002

It is recognised in marketing that the study of buyer behaviour includes analysis of instrumental acts: that is, acts necessary in obtaining the goal object and the acts involved in consuming it. A technology that eases the difficulty level of instrumental acts such as visiting a purchase outlet to purchase a product is the Internet. Technically, the Internet minimises customer’s transaction costs such as time spent travelling to a store to purchase a product. Yet, in spite of its benefits, only one‐in‐four Internet users shop online. An empirical analysis of surveyed beliefs, attitudes, and intentions regarding Internet purchase of air tickets revealed that security concerns about the Internet make consumers avoid online purchase of air tickets. It is suggested that Internet marketers focus on modifying the attitudinal structure of consumers.
GENESYS: an expert system for production scheduling
Authors: Metaxiotis Kostas S. , Psarras John E. , Askounis Dimitris T.
Published: October 2002

Planning and scheduling are forms of decision making, which play a crucial role in manufacturing as well as in service industries. In the current competitive environment, effective sequencing and scheduling has become a necessity for survival in the marketplace. A great challenge for today’s companies is not only how to adapt to this changing, competitive business environment but also how to draw a competitive advantage from the way in which they choose to do so. Intelligent solutions, based on expert systems, to solve problems in the field of production planning and scheduling are becoming more and more widespread nowadays. Proposes an expert system, which uses the prevailing conditions in the industrial environment in order to select and “fire” dynamically the most appropriate scheduling algorithm from a library of many candidate algorithms.
IIM digital library system: consortia‐based approach
Authors: Paul Pandian M. , Jambhekar Ashok , Karisiddappa C.R.
Published: October 2002

Though there have been many cooperative efforts for resource sharing among the libraries of India in the last two decades, it is hard to find one successful programme that could be used as a benchmark to replicate in other libraries. The main factors that affect these kinds of efforts are more human and attitudinal than technological or economical. The information environment today is very much conducive enough to tackle the problems faced earlier. With the advent of the Internet and World Wide Web, it is possible to provide instantaneous access to the sources available not only within the organization, but other institutions that participate in the consortia programme. This paper provides a framework for the design and development of an intranet model based on a consortia approach. This model will facilitate information access and use by providing a single Web‐enabled window to the information users of the participating institutions in the consortia programme not only to their own resources but sources in the other institutions as well. This will bridge the gap between information resource rich and information deficient libraries and will enhance the information base, shared access and optimum utilization of information resources at an affordable cost.