bluuebunny/crossref_metadata_2025 huggingface dataset:
Bruton's Tyrosine Kinase Cooperates with the B Cell Linker Protein SLP-65 as a Tumor Suppressor in Pre-B Cells
Authors: Kersseboom Rogier , Middendorp Sabine , Dingjan Gemma M. , Dahlenborg Katarina , Reth Michael , Jumaa Hassan , Hendriks Rudolf W.
Published: July 2003

Expression of the pre-B cell receptor (pre-BCR) leads to activation of the adaptor molecule SLP-65 and the cytoplasmic kinase Btk. Mice deficient for one of these signaling proteins have an incomplete block in B cell development at the stage of large cycling pre-BCR+CD43+ pre-B cells. Our recent findings of defective SLP-65 expression in ∼50% of childhood pre-B acute lymphoblastic leukemias and spontaneous pre-B cell lymphoma development in SLP-65−/− mice demonstrate that SLP-65 acts as a tumor suppressor. To investigate cooperation between Btk and SLP-65, we characterized the pre-B cell compartment in single and double mutant mice, and found that the two proteins have a synergistic role in the developmental progression of large cycling into small resting pre-B cells. We show that Btk/SLP-65 double mutant mice have a dramatically increased pre-B cell tumor incidence (∼75% at 16 wk of age), as compared with SLP-65 single deficient mice (<10%). These findings demonstrate that Btk cooperates with SLP-65 as a tumor suppressor in pre-B cells. Furthermore, transgenic low-level expression of a constitutive active form of Btk, the E41K-Y223F mutant, prevented tumor formation in Btk/SLP-65 double mutant mice, indicating that constitutive active Btk can substitute for SLP-65 as a tumor suppressor.
A Defect in Tryptophan Catabolism Impairs Tolerance in Nonobese Diabetic Mice
Authors: Grohmann Ursula , Fallarino Francesca , Bianchi Roberta , Orabona Ciriana , Vacca Carmine , Fioretti Maria C. , Puccetti Paolo
Published: July 2003

The predisposition of nonobese diabetic (NOD) mice to develop autoimmunity reflects deficiencies in both peripheral and central tolerance. Several defects have been described in these mice, among which aberrant antigen-presenting cell function and peroxynitrite formation. Prediabetes and diabetes in NOD mice have been targeted with different outcomes by a variety of immunotherapies, including interferon (IFN)-γ. This cytokine may be instrumental in specific forms of tolerance by virtue of its ability to activate immunosuppressive tryptophan catabolism. Here, we provide evidence that IFN-γ fails to induce tolerizing properties in dendritic cells from highly susceptible female mice early in prediabetes. This effect is associated with impaired tryptophan catabolism, is related to transient blockade of the Stat1 pathway of intracellular signaling by IFN-γ, and is caused by peroxynitrite production. However, the use of a peroxynitrite inhibitor can rescue tryptophan catabolism and tolerance in those mice. This is the first report of an experimental autoimmune disease in which defective tolerance is causally linked to impaired tryptophan catabolism.
Canonical bases and quiver varieties
Authors: Varagnolo Michela , Vasserot Eric
Published: June 2003

We prove the existence of canonical bases in the

K
K

-theory of quiver varieties. This existence was conjectured by Lusztig.
New Insights into the Bioenergetics of Mitochondrial Disorders Using Intracellular ATP Reporters
Authors: Gajewski Carl D. , Yang Lichuan , Schon Eric A. , Manfredi Giovanni
Published: July 2003

Mutations in mitochondrial DNA (mtDNA) cause impairment of ATP synthesis. It was hypothesized that high-energy compounds, such as ATP, are compartmentalized within cells and that different cell functions are sustained by different pools of ATP, some deriving from mitochondrial oxidative phosphorylation (OXPHOS) and others from glycolysis. Therefore, an OXPHOS dysfunction may affect different cell compartments to different extents. To address this issue, we have used recombinant forms of the ATP reporter luciferase localized in different cell compartments— the cytosol, the subplasma membrane region, the mitochondrial matrix, and the nucleus— of cells containing either wild-type or mutant mtDNA. We found that with glycolytic substrates, both wild-type and mutant cells were able to maintain adequate ATP supplies in all compartments. Conversely, with the OXPHOS substrate pyruvate ATP levels collapsed in all cell compartments of mutant cells. In wild-type cells normal levels of ATP were maintained with pyruvate in the cytosol and in the subplasma membrane region, but, surprisingly, they were reduced in the mitochondria and, to a greater extent, in the nucleus. The severe decrease in nuclear ATP content under “OXPHOS-only” conditions implies that depletion of nuclear ATP plays an important, and hitherto unappreciated, role in patients with mitochondrial dysfunction.
SPARC Inhibits Epithelial Cell Proliferation in Part through Stimulation of the Transforming Growth Factor-β–Signaling System
Authors: Schiemann Barbara J. , Neil Jason R. , Schiemann William P.
Published: July 2003

Secreted protein, acidic and rich in cysteine (SPARC) is a multifunctional secreted protein that regulates cell–cell and cell–matrix interactions, leading to alterations in cell adhesion, motility, and proliferation. Although SPARC is expressed in epithelial cells, its ability to regulate epithelial cell growth remains largely unknown. We show herein that SPARC strongly inhibited DNA synthesis in transforming growth factor (TGF)-β–sensitive Mv1Lu cells, whereas moderately inhibiting that in TGF-β–insensitive Mv1Lu cells (i.e., R1B cells). Overexpression of dominant-negative Smad3 in Mv1Lu cells, which abrogated growth arrest by TGF-β, also attenuated growth arrest stimulated by SPARC. Moreover, the extracellular calcium-binding domain of SPARC (i.e., SPARC-EC) was sufficient to inhibit Mv1Lu cell proliferation but not that of R1B cells. Similar to TGF-β and thrombospondin-1, treatment of Mv1Lu cells with SPARC or SPARC-EC stimulated Smad2 phosphorylation and Smad2/3 nuclear translocation: the latter response to all agonists was abrogated in R1B cells or by pretreatment of Mv1Lu cells with neutralizing TGF-β antibodies. SPARC also stimulated Smad2 phosphorylation in MB114 endothelial cells but had no effect on bone morphogenetic protein-regulated Smad1 phosphorylation in either Mv1Lu or MB114 cells. Finally, SPARC and SPARC-EC stimulated TGF-β–responsive reporter gene expression through a TGF-β receptor- and Smad2/3-dependent pathway in Mv1Lu cells. Collectively, our findings identify a novel mechanism whereby SPARC inhibits epithelial cell proliferation by selectively commandeering the TGF-β signaling system, doing so through coupling of SPARC-EC to a TGF-β receptor- and Smad2/3-dependent pathway.
Caspase-3-mediated Cleavage of Cdc6 Induces Nuclear Localization of p49-truncated Cdc6 and Apoptosis
Authors: Yim Hyungshin , Jin Ying Hua , Park Byoung Duck , Choi Hye Jin , Lee Seung Ki
Published: July 2003

We show that Cdc6, an essential initiation factor for DNA replication, undergoes caspase-3–mediated cleavage in the early stages of apoptosis in HeLa cells and SK-HEP-1 cells induced by etoposide, paclitaxel, ginsenoside Rh2, or tumor necrosis factor-related apoptosis-inducing ligand. The cleavage occurs at the SEVD442/G motif and generates an N-terminal truncated Cdc6 fragment (p49-tCdc6) that lacks the carboxy-terminal nuclear export sequence. Cdc6 is known to be phosphorylated by cyclin A-cyclin dependent kinase 2 (Cdk2), an event that promotes its exit from the nucleus and probably blocks it from initiating inappropriate DNA replication. In contrast, p49-tCdc6 translocation to the cytoplasm is markedly reduced under the up-regulated conditions of Cdk2 activity, which is possibly due to the loss of nuclear export sequence. Thus, truncation of Cdc6 results in an increased nuclear retention of p49-tCdc6 that could act as a dominant negative inhibitor of DNA replication and its accumulation in the nucleus could promote apoptosis. Supporting this is that the ectopic expression of p49-tCdc6 not only promotes apoptosis of etoposide-induced HeLa cells but also induces apoptosis in untreated cells. Thus, the caspase-mediated cleavage of Cdc6 creates a truncated Cdc6 fragment that is retained in the nucleus and induces apoptosis.
Amino Acid Starvation and Gcn4p Regulate Adhesive Growth andFLO11Gene Expression inSaccharomyces cerevisiae
Authors: Braus Gerhard H. , Grundmann Olav , Brückner Stefan , Mösch Hans-Ulrich
Published: July 2003

In baker's yeast Saccharomyces cerevisiae, cell-cell and cell-surface adhesion are required for haploid invasive growth and diploid pseudohyphal development. These morphogenetic events are induced by starvation for glucose or nitrogen and require the cell surface protein Flo11p. We show that amino acid starvation is a nutritional signal that activates adhesive growth and expression of FLO11 in both haploid and diploid strains in the presence of glucose and ammonium, known suppressors of adhesion. Starvation-induced adhesive growth requires Flo11p and is under control of Gcn2p and Gcn4p, elements of the general amino acid control system. Tpk2p and Flo8p, elements of the cAMP pathway, are also required for activation but not Ste12p and Tec1p, known targets of the mitogen-activated protein kinase cascade. Promoter analysis of FLO11 identifies one upstream activation sequence (UASR) and one repression site (URS) that confer regulation by amino acid starvation. Gcn4p is not required for regulation of the UASRby amino acid starvation, but seems to be indirectly required to overcome the negative effects of the URS on FLO11 transcription. In addition, Gcn4p controls expression of FLO11 by affecting two basal upstream activation sequences (UASB). In summary, our study suggests that amino acid starvation is a nutritional signal that triggers a Gcn4p-controlled signaling pathway, which relieves repression of FLO11 gene expression and induces adhesive growth.
DC3, the 21-kDa Subunit of the Outer Dynein Arm-Docking Complex (ODA-DC), Is a Novel EF-Hand Protein Important for Assembly of Both the Outer Arm and the ODA-DC
Authors: Casey Diane M. , Inaba Kazuo , Pazour Gregory J. , Takada Saeko , Wakabayashi Ken-ichi , Wilkerson Curtis G. , Kamiya Ritsu , Witman George B.
Published: July 2003

The outer dynein arm-docking complex (ODA-DC) is a microtubule-associated structure that targets the outer dynein arm to its binding site on the flagellar axoneme ( Takada et al. 2002 . Mol. Biol. Cell 13, 1015–1029). The ODA-DC of Chlamydomonas contains three proteins, referred to as DC1, DC2, and DC3. We here report the isolation and sequencing of genomic and full-length cDNA clones encoding DC3. The sequence predicts a 21,341 Da protein with four EF-hands that is a member of the CTER (calmodulin, troponin C, essential and regulatory myosin light chains) group and is most closely related to a predicted protein from Plasmodium. The DC3 gene, termed ODA14, is intronless. Chlamydomonas mutants that lack DC3 exhibit slow, jerky swimming because of loss of some but not all outer dynein arms. Some outer doublet microtubules without arms had a “partial” docking complex, indicating that DC1 and DC2 can assemble in the absence of DC3. In contrast, DC3 cannot assemble in the absence of DC1 or DC2. Transformation of a DC3-deletion strain with the wild-type DC3 gene rescued both the motility phenotype and the structural defect, whereas a mutated DC3 gene was incompetent to rescue. The results indicate that DC3 is important for both outer arm and ODA-DC assembly.
Mitogen-activated Protein Kinase Stimulation of Ca2+Signaling Is Required for Survival of Endoplasmic Reticulum Stress in Yeast
Authors: Bonilla Myriam , Cunningham Kyle W.
Published: July 2003

Endoplasmic reticulum (ER) stress in the budding yeast Saccharomyces cerevisiae triggers Ca2+influx through a plasma membrane channel composed of Cch1 and Mid1. This response activates calcineurin, which helps to prevent cell death during multiple forms of ER stress, including the response to azole-class antifungal drugs. Herein, we show that ER stress activates the cell integrity mitogen-activate protein kinase cascade in yeast and that the activation of Pkc1 and Mpk1 is necessary for stimulation of the Cch1-Mid1 Ca2+channel independent of many known targets of Mpk1 (Rlm1, Swi4, Swi6, Mih1, Hsl1, and Swe1). ER stress generated in response to miconazole, tunicamycin, or other inhibitors also triggered a transient G2/M arrest that depended upon the Swe1 protein kinase. Calcineurin played little role in the Swe1-dependent cell cycle arrest and Swe1 had little effect on calcineurin-dependent avoidance of cell death. These findings help to clarify the interactions between Mpk1, calcineurin, and Swe1 and suggest that the calcium cell survival pathway promotes drug resistance independent of both the unfolded protein response and the G2/M cell cycle checkpoint.
Cross Talk between Tetanus Neurotoxin-insensitive Vesicle-associated Membrane Protein-mediated Transport and L1-mediated Adhesion
Authors: Alberts Philipp , Rudge Rachel , Hinners Ina , Muzerelle Aude , Martinez-Arca Sonia , Irinopoulou Theano , Marthiens Véronique , Tooze Sharon , Rathjen Fritz , Gaspar Patricia , Galli Thierry
Published: July 2003

The membrane-trafficking pathway mediated by tetanus neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP) in neurons is still unknown. We show herein that TI-VAMP expression is necessary for neurite outgrowth in PC12 cells and hippocampal neurons in culture. TI-VAMP interacts with plasma membrane and endosomal target soluble N-ethylmaleimide-sensitive factor attachment protein receptors, suggesting that TI-VAMP mediates a recycling pathway. L1, a cell-cell adhesion molecule involved in axonal outgrowth, colocalized with TI-VAMP in the developing brain, neurons in culture, and PC12 cells. Plasma membrane L1 was internalized into the TI-VAMP–containing compartment. Silencing of TI-VAMP resulted in reduced expression of L1 at the plasma membrane. Finally, using the extracellular domain of L1 and N-cadherin immobilized on beads, we found that the silencing of TI-VAMP led to impaired L1- but not N-cadherin–mediated adhesion. Furthermore, TI-VAMP- but not synaptobrevin 2-containing vesicles accumulated at the site of the L1 bead-cell junction. We conclude that TI-VAMP mediates the intracellular transport of L1 and that L1-mediated adhesion controls this membrane trafficking, thereby suggesting an important cross talk between membrane trafficking and cell-cell adhesion.
Localization of Pavarotti-KLP in LivingDrosophilaEmbryos Suggests Roles in Reorganizing the Cortical Cytoskeleton during the Mitotic Cycle
Authors: Minestrini Gianluca , Harley Alyssa S. , Glover David M.
Published: July 2003

Pav-KLP is the Drosophila member of the MKLP1 family essential for cytokinesis. In the syncytial blastoderm embryo, GFP-Pav-KLP cyclically associates with astral, spindle, and midzone microtubules and also to actomyosin pseudocleavage furrows. As the embryo cellularizes, GFP-Pav-KLP also localizes to the leading edge of the furrows that form cells. In mononucleate cells, nuclear localization of GFP-Pav-KLP is mediated through NLS elements in its C-terminal domain. Mutants in these elements that delocalize Pav-KLP to the cytoplasm in interphase do not affect cell division. In mitotic cells, one population of wild-type GFP-Pav-KLP associates with the spindle and concentrates in the midzone at anaphase B. A second is at the cell cortex on mitotic entry and later concentrates in the region of the cleavage furrow. An ATP binding mutant does not localize to the cortex and spindle midzone but accumulates on spindle pole microtubules to which actin is recruited. This leads either to failure of the cleavage furrow to form or later defects in which daughter cells remain connected by a microtubule bridge. Together, this suggests Pav-KLP transports elements of the actomyosin cytoskeleton to plus ends of astral microtubules in the equatorial region of the cell to permit cleavage ring formation.
The Interplay between Folding-facilitating Mechanisms inTrypanosoma cruziEndoplasmic Reticulum
Authors: Conte Ianina , Labriola Carlos , Cazzulo Juan J. , Docampo Roberto , Parodi Armando J.
Published: July 2003

Lectin (calreticulin [CRT])-N-glycan–mediated quality control of glycoprotein folding is operative in trypanosomatid protozoa but protein-linked monoglucosylated N-glycans are exclusively formed in these microorganisms by UDP-Glc:glycoprotein glucosyltransferase (GT)-dependent glucosylation. The gene coding for this enzyme in the human pathogen Trypanosoma cruzi was identified and sequenced. Even though several of this parasite glycoproteins have been identified as essential components of differentiation and mammalian cell invasion processes, disruption of both GT-encoding alleles did not affect cell growth rate of epimastigote form parasites and only partially affected differentiation and mammalian cell invasion. The cellular content of one of the already identified T. cruzi glycoprotein virulence factors (cruzipain, a lysosomal proteinase) only showed a partial (5–20%) decrease in GT null mutants in spite of the fact that >90% of all cruzipain molecules interacted with CRT during their folding process in wild-type cells. Although extremely mild cell lysis and immunoprecipitation procedures were used, no CRT-cruzipain interaction was detected in GT null mutants but secretion of the proteinase was nevertheless delayed because of a lengthened interaction with Grp78/BiP probably caused by the detected induction of this chaperone in GT null mutants. This result provides a rationale for the absence of a more drastic consequence of GT absence. It was concluded that T. cruzi endoplasmic reticulum folding machinery presents an exquisite plasticity that allows the parasite to surmount the absence of the glycoprotein-specific folding facilitation mechanism.
A novel pseudoknot element is essential for the action of a yeast telomerase
Authors: Tzfati Yehuda , Knight Zachary , Roy Jagoree , Blackburn Elizabeth H.
Published: July 2003

Telomerase contains an essential RNA, which includes the template sequence copied by the reverse transcription action of telomerase into telomeric DNA. Using phylogenetic comparison, we identified seven conserved sequences in telomerase RNAs fromKluyveromycesbudding yeasts. We show that two of these sequences, CS3 and CS4, are essential for normal telomerase function and can base-pair to form a putative long-range pseudoknot. Disrupting this base-pairing was deleterious to cell growth, telomere maintenance, and telomerase activity. Restoration of the base-pairing potential alleviated these phenotypes. Mutating this pseudoknot caused a novel mode of shifting of the boundaries of the RNA template sequence copied by telomerase. A phylogenetically derived model of yeast TER structure indicates that these RNAs can form two alternative predicted core conformations of similar stability: one brings the CS3/CS4 pseudoknot spatially close to the template; in the other, CS3 and CS4 move apart and the conformation of the template is altered. We propose that such disruption of the pseudoknot, and potentially the predicted telomerase RNA conformation, affects polymerization to cause the observed shifts in template usage.
IRF-4,8 orchestrate the pre-B-to-B transition in lymphocyte development
Authors: Lu Runqing , Medina Kay L. , Lancki David W. , Singh Harinder
Published: July 2003

B-lymphocyte development involves sequential DNA rearrangements of immunoglobulin (Ig) heavy (μ) and light (κ, λ) chain loci and is dependent on transient expression of μ containing pre-antigen receptor complexes (pre-BCR). To date, genetic analysis has not identified transcription factors that coordinate the pre-B-to-B transition. We demonstrate that the related interferon regulatory factors IRF-4 (Pip) and IRF-8 (ICSBP) are required for Ig light but not heavy-chain gene rearrangement. In the absence of these transcription factors, B-cell development is arrested at the cycling pre-B-cell stage and the mutant cells fail to down-regulate the pre-BCR. On the basis of molecular analysis, we propose that IRF-4,8 function as a genetic switch to down-regulate surrogate light-chain gene expression and induce conventional light-chain gene transcription and rearrangement.
Slx1—Slx4 is a second structure-specific endonuclease functionally redundant with Sgs1—Top3
Authors: Fricke William M. , Brill Steven J.
Published: July 2003

The RecQ DNA helicases human BLM and yeast Sgs1 interact with DNA topoisomerase III and are thought to act on stalled replication forks to maintain genome stability. To gain insight into this mechanism, we previously identifiedSLX1andSLX4as genes that are required for viability and for completion of rDNA replication in the absence ofSGS1–TOP3. Here we show thatSLX1andSLX4encode a heteromeric structure-specific endonuclease. The Slx1–Slx4 nuclease is active on branched DNA substrates, particularly simple-Y, 5′-flap, or replication forkstructures. It cleaves the strand bearing the 5′ nonhomologous arm at the branch junction and generates ligatable nicked products from 5′-flap or replication fork substrates. Slx1 is the founding member of a family of proteins with a predicted URI nuclease domain and PHD-type zinc finger. This subunit displays weakstructure-specific endonuclease activity on its own, is stimulated 500-fold by Slx4, and requires the PHD finger for activity in vitro and in vivo. Both subunits are required in vivo for resistance to DNA damage by methylmethane sulfonate (MMS). We propose that Sgs1–Top3 acts at the termination of rDNA replication to decatenate stalled forks, and, in its absence, Slx1–Slx4 cleaves these stalled forks.
A novel class of secreted hydrophobic proteins is involved in aerial hyphae formation inStreptomyces coelicolorby forming amyloid-like fibrils
Authors: Claessen Dennis , Rink Rick , de Jong Wouter , Siebring Jeroen , de Vreugd Peter , Boersma F.G. Hidde , Dijkhuizen Lubbert , Wösten Han A.B.
Published: July 2003

Streptomycetes exhibit a complex morphological differentiation. After a submerged mycelium has been formed, filaments grow into the air to septate into spores. A class of eight hydrophobic secreted proteins, ChpA–H, was shown to be instrumental in the development ofStreptomyces coelicolor. Mature forms of ChpD–H are up to 63 amino acids in length, and those of ChpA–C are larger (±225 amino acids). ChpA–C contain two domains similar to ChpD–H, as well as a cell-wall sorting signal. Thechpgenes were expressed in submerged mycelium (chpEandchpH) as well as in aerial hyphae (chpA–H). Formation of aerial hyphae was strongly affected in a strain in which sixchpgenes were deleted (ΔchpABCDEH). A mixture of ChpD–H purified from cell walls of aerial hyphae complemented the ΔchpABCDEHstrain extracellularly, and it accelerated development in the wild-type strain. The protein mixture was highly surface active, and it self-assembled into amyloid-like fibrils at the water–air interface. The fibrils resembled those of a surface layer of aerial hyphae. We thus conclude that the amyloid-like fibrils of ChpD–H lower the water surface tension to allow aerial growth and cover aerial structures, rendering them hydrophobic. ChpA–C possibly bind ChpD–H to the cell wall.
The chaplins: a family of hydrophobic cell-surface proteins involved in aerial mycelium formation inStreptomyces coelicolor
Authors: Elliot Marie A. , Karoonuthaisiri Nitsara , Huang Jianqiang , Bibb Maureen J. , Cohen Stanley N. , Kao Camilla M. , Buttner Mark J.
Published: July 2003

The filamentous bacteriumStreptomyces coelicolordifferentiates by forming specialized, spore-bearing aerial hyphae that grow into the air. Using microarrays, we identified genes that are down-regulated in a mutant unable to erect aerial hyphae. Through this route, we identified a previously unknown layer of aerial mycelium surface proteins (the “chaplins”). The chaplins share a hydrophobic domain of ∼40 residues (the “chaplin domain”), and all have a secretion signal. The five short chaplins (ChpD,E,F,G,H) have one chaplin domain, whereas the three long chaplins (ChpA,B,C) have two chaplin domains and a C-terminal “sorting signal” that targets them for covalent attachment to the cell wall by sortase enzyme. Expression of the two chaplin genes examined (chpE, chpH) depended on aerial hyphae formation but not sporulation, andegfpfusions showed their expression localized to aerial structures. Mass spectrometry of cell wall extracts confirmed that the short chaplins localized to the cell surface. Deletion of chaplin genes caused severe delays in aerial hyphae formation, a phenotype rescued by exogenous application of chaplin proteins. These observations implicate the chaplins in aerial mycelium formation, and suggest that coating of the envelope by the chaplins is required for aerial hyphae to grow out of the aqueous environment of the substrate mycelium into the air.
Hydrotropism Interacts with Gravitropism by Degrading Amyloplasts in Seedling Roots of Arabidopsis and Radish
Authors: Takahashi Nobuyuki , Yamazaki Yutaka , Kobayashi Akie , Higashitani Atsushi , Takahashi Hideyuki
Published: June 2003

In response to a moisture gradient, roots exhibit hydrotropism to control the orientation of their growth. To exhibit hydrotropism, however, they must overcome the gravitropism that is dominant on Earth. We found that moisture gradient or water stress caused immediate degradation of the starch anchors, amyloplasts, in root columella cells of Arabidopsis and radish (Raphanus sativus). Namely, development of hydrotropic response was accompanied by a simultaneous reduction in starch content in columella cells. Rapid degradation of amyloplasts in columella cells also occurred in the water-stressed roots with sorbitol or mannitol. Both hydrotropically stimulated and water-stressed roots showed a reduced responsiveness to gravity. Roots of a starchless mutant, pgm1-1, showed an enhanced hydrotropism compared with that of the wild type. These results suggest that the reduced responsiveness to gravity is, at least in part, attributable to the degradation of amyloplasts in columella cells. Thus, the reduction in gravitropism allows the roots to exhibit hydrotropism.
An Arabidopsis Inositol 5-Phosphatase Gain-of-Function Alters Abscisic Acid Signaling
Authors: Burnette Ryan N. , Gunesekera Bhadra M. , Gillaspy Glenda E.
Published: June 2003

Signals can be perceived and amplified at the cell membrane by receptors coupled to the production of a variety of second messengers, including inositol 1,4,5-trisphosphate (IP3). We previously have identified 15 putative inositol 5-phosphatases (5PTases) from Arabidopsis and shown that At5PTase1 can hydrolyze IP3. To determine whether At5PTase1 can terminate IP3-mediated signaling, we analyzed transgenic plants ectopically expressing At5PTase1. Stomata from leaves of At5PTase1 transgenic plants were abscisic acid (ABA) and light insensitive, and ABA induction of genes was delayed. Quantification of IP3 in plants exposed to ABA indicated that ABA induced two IP3 increases in wild-type plants. Both of these IP3 increases were reduced in At5PTase1 transgenic plants, indicating that IP3 may be necessary for stomatal closure and temporal control of ABA-induced gene expression. To determine if ABA could induce expression of At5PTase1, we examined RNA and protein levels of At5PTase1 in wild-type plants exposed to ABA. Our results indicate that At5PTase1 is up-regulated in response to ABA. This is consistent with At5PTase1 acting as a signal terminator of ABA signaling.
Inorganic Carbon Limitation and Light Control the Expression of Transcripts Related to the CO2-Concentrating Mechanism in the Cyanobacterium Synechocystis sp. Strain PCC6803
Authors: McGinn Patrick J. , Price G. Dean , Maleszka Ryszard , Badger Murray R.
Published: June 2003

The cyanobacterium Synechocystis sp. strain PCC6803 possesses three modes of inorganic carbon (Ci) uptake that are inducible under Ci stress and that dramatically enhance the efficiency of the CO2-concentrating mechanism (CCM). The effects of Ci limitation on the mRNA transcript abundance of these inducible uptake systems and on the physiological expression of the CCM were investigated in detail in this cyanobacterium. Transcript abundance was assessed with semiquantitative and real-time reverse transcriptase-polymerase chain reaction techniques. Cells aerated with CO2-free air for 30 min in the light, but not in the dark, depleted the total [Ci] to near zero levels. Under these conditions, the full physiological expression of the CCM was apparent within 2 h. Transcripts for the three inducible Ci uptake systems,ndhF3, sbtA, and cmpA, showed near-maximal abundance at 15 min under Ci limitation. The transcriptional regulators, cmpR andndhR, were more moderately expressed, whereas therbcLXS and ccmK-N operons andndhF4/ndhD4/chpX and ccaAgenes were insensitive to the low-Ci treatment. The combined requirement of low Ci and light for the expression of several CCM-related transcripts was examined using real-time reverse transcriptase-polymerase chain reaction. CmpA,ndhF3, and sbtA were strongly expressed in the light, but not in the dark, under low-Ci conditions. We could find no evidence for induction of these or other CCM-related genes by a high-light treatment under high-CO2 conditions. This provided evidence that high-light stress alone could not trigger the expression of CCM-related transcripts in Synechocystissp. PCC6803. Potential signals triggering induction of the high-affinity state of the CCM are discussed.
Nuclear Genes That Encode Mitochondrial Proteins for DNA and RNA Metabolism Are Clustered in the Arabidopsis Genome[W]
Authors: Elo Annakaisa , Lyznik Anna , Gonzalez Delkin O. , Kachman Stephen D. , Mackenzie Sally A.
Published: July 2003

The plant mitochondrial genome is complex in structure, owing to a high degree of recombination activity that subdivides the genome and increases genetic variation. The replication activity of various portions of the mitochondrial genome appears to be nonuniform, providing the plant with an ability to modulate its mitochondrial genotype during development. These and other interesting features of the plant mitochondrial genome suggest that adaptive changes have occurred in DNA maintenance and transmission that will provide insight into unique aspects of plant mitochondrial biology and mitochondrial-chloroplast coevolution. A search in the Arabidopsis genome for genes involved in the regulation of mitochondrial DNA metabolism revealed a region of chromosome III that is unusually rich in genes for mitochondrial DNA and RNA maintenance. An apparently similar genetic linkage was observed in the rice genome. Several of the genes identified within the chromosome III interval appear to target the plastid or to be targeted dually to the mitochondria and the plastid, suggesting that the process of endosymbiosis likely is accompanied by an intimate coevolution of these two organelles for their genome maintenance functions.
Molecular and Phylogenetic Analyses of the Complete MADS-Box Transcription Factor Family in Arabidopsis
Authors: Par̆enicová Lucie , de Folter Stefan , Kieffer Martin , Horner David S. , Favalli Cristina , Busscher Jacqueline , Cook Holly E. , Ingram Richard M. , Kater Martin M. , Davies Brendan , Angenent Gerco C. , Colombo Lucia
Published: July 2003

MADS-box transcription factors are key regulators of several plant development processes. Analysis of the complete Arabidopsis genome sequence revealed 107 genes encoding MADS-box proteins, of which 84% are of unknown function. Here, we provide a complete overview of this family, describing the gene structure, gene expression, genome localization, protein motif organization, and phylogenetic relationship of each member. We have divided this transcription factor family into five groups (named MIKC, Mα, Mβ, Mγ, and Mδ) based on the phylogenetic relationships of the conserved MADS-box domain. This study provides a solid base for functional genomics studies into this important family of plant regulatory genes, including the poorly characterized group of M-type MADS-box proteins. MADS-box genes also constitute an excellent system with which to study the evolution of complex gene families in higher plants.
Gibberellin Biosynthesis and Response during Arabidopsis Seed Germination[W]
Authors: Ogawa Mikihiro , Hanada Atsushi , Yamauchi Yukika , Kuwahara Ayuko , Kamiya Yuji , Yamaguchi Shinjiro
Published: July 2003

The hormone-mediated control of plant growth and development involves both synthesis and response. Previous studies have shown that gibberellin (GA) plays an essential role in Arabidopsis seed germination. To learn how GA stimulates seed germination, we performed comprehensive analyses of GA biosynthesis and response using gas chromatography–mass spectrometry and oligonucleotide-based DNA microarray analysis. In addition, spatial correlations between GA biosynthesis and response were assessed by in situ hybridization. We identified a number of transcripts, the abundance of which is modulated upon exposure to exogenous GA. A subset of these GA-regulated genes was expressed in accordance with an increase in endogenous active GA levels, which occurs just before radicle emergence. The GA-responsive genes identified include those responsible for synthesis, transport, and signaling of other hormones, suggesting the presence of uncharacterized crosstalk between GA and other hormones. In situ hybridization analysis demonstrated that the expression of GA-responsive genes is not restricted to the predicted site of GA biosynthesis, suggesting that GA itself, or GA signals, is transmitted across different cell types during Arabidopsis seed germination.
Trust evaluation: an AHP and multi‐objective programming approach
Authors: Radcliffe Larry L. , Schniederjans Marc J.
Published: July 2003

Establishing trust within groups or teams of scientists and technicians working on large‐scale projects is considered an essential critical success factor when working in a virtual environment. To build trust among team members for any project requires a selection decision on which trust factors will best achieve the goals of the project. This paper presents application results of using two analytic methodologies used to evaluate trust survey information from the Spallation Neutron Source (SNS), the USA’s largest science project. The two decision methodologies produced results that helped support SNS management’s judgment that uniquely selected trust categories should be emphasized to build trust on this project.
The selection of friendly take‐over targets in the UK: some empirical evidence
Authors: Weir Charlie , Laing David
Published: July 2003

The vast majority of the acquisitions of UK‐quoted companies are friendly. This paper compares the accounting, financial and governance characteristics of firms that were acquired by friendly take‐over with those of firms that were not taken over. Evidence is found that targets exhibited superior performance in terms of the return on assets and the sales‐to‐assets ratio. However, they underperformed in terms of capital expenditure and the market‐to‐book ratio. No difference was found in the extent to which targets adopted the board structures recommended in the Code of Best Practice. The results therefore suggest that acquirers target firms that are relatively undervalued by the capital market but do not show signs of poor profitability or ineffective board structures.
Ethical behaviour: the means for creating and maintaining better reputations in arts organisations
Authors: Wood Greg , Rentschler Ruth
Published: July 2003

Arts organisations, unsure of the level of continued government funding available and confronted with the need ever to improve, are seeking new ideas upon which they can focus. At a time when leadership and governance in arts organisations have changed in line with cultural expectations, how is their ethical stance assessed? How does their ethical stance impact on reputation? The challenge to build a good reputation starts at the top of the organisation; however, traditionally, one type of arts organisation, art museums, has focused on the activities level. In an age of globalisation, economic restructuring and technological change, museums therefore may be seen as a contradiction. Traditionally seen as temples for the muses, today’s museums are being challenged to be ethical for society and to build their reputation. As a solution, proposes a cooperative model of cultural organisational ethics that attempts to provide a framework by which arts organisations can put in place ethical artefacts that enhance organisational reputation, rather than detract from it.
Transitioning operations to accommodate growing pains in evolving companies: an application of product profiling to a service company
Authors: Southard Peter B. , Swenseth Scott R.
Published: July 2003

As businesses progress through their organizational lifecycle, many experience growing pains associated with increased volume, product line breadth, personnel, and the complexity associated with managing larger businesses. It is essential that the company have the ability to recognize these and develop methods of dealing with them if they expect to survive. While many authors address the area of how to grow in terms of marketing, product development and financing and, while they note that there are risks to rapid growth, little information is available on how to recognize trouble spots, analyze them and accommodate them. The product profile is a management tool that helps decision‐makers to identify problems that have evolved through time and to identify impending opportunities on the horizon. Discusses the advantages of adapting product profiling to services to identify and accommodate growing pains and then provides an example of its successful use by a service company.
Classifying and selecting e‐CRM applications: an analysis‐based proposal
Authors: Adebanjo Dotun
Published: July 2003

The application of technology to customer relationship management (CRM) initiatives (e‐CRM) is one of the fastest growing technological developments. However, there is sufficient evidence to show that many CRM initiatives do not achieve the desired result. One of the reasons for this is the lack of clarity that surrounds the classification and selection considerations of CRM applications. Identifies and discusses key factors that need to be considered when electronic CRM solutions are to be implemented. Among other findings, proposes perspectives from which e‐CRM implementation may be viewed in addition to identifying three integration dimensions applicable to e‐CRM solutions. Concludes that, while e‐CRM applications could enhance the delivery of a CRM strategy, such applications should be chosen carefully to fit in with organisational culture, process and legacy IT systems. The financial and human resource cost as well as the amount of time required for implementation of a CRM application should also be key factors in the selection of e‐CRM applications.
Skill or diploma? The potential influence of skill‐based pay systems on sources of skills acquisition and degree programs
Authors: Eugene Hughes R.
Published: June 2003

A degree or diploma has traditionally served as a general criterion for hiring and pay decisions. This approach is inconsistent with emerging skill‐ or competency‐based compensations systems. Such systems only recognize and pay for the skill or competency required by the task to which an employee is assigned. As employers adopt skill‐based pay systems, it is reasonable to ask whether they will continue to use degrees and diplomas in their hiring and pay decisions. A shift away from the diploma as a criterion for hiring and pay decision may influence educational systems to offer both diplomas and skills acquisition programs.
Harvesting and using corporate knowledge
Authors: Heath James
Published: June 2003

Knowledge management (KM) has been a ten‐year “buzzword”, yet few successful KM projects have been written up in the literature and few organisations seem to claim strategic advantage from KM. This paper suggests that technology may at last be able to provide the tools necessary for effective KM. More importantly, organisations are beginning to realise that key strategic advantage arises from the harvesting of tacit knowledge in addition to the more easily handled explicit knowledge. Together, tacit and explicit knowledge management can give rise to a corporate knowledge store – an organisational memory.
Strategic planning for knowledge management implementation in engineering firms
Authors: Shankar Ravi , Singh  , Gupta Amol , Narain Rakesh
Published: June 2003

Knowledge management (KM) is the process of leveraging organizational knowledge to deliver long‐term advantage to a business and is based on a business strategy that involves engineering various knowledge‐centric business processes and developing organization structures to support these. These, in turn, require technology to capture, codify, store, disseminate and reuse the knowledge. Successful deployment of KM is not a simple process. This paper suggests that a major reason for the failure of many KM projects is the absence of a well‐defined strategic plan to guide implementation. This paper discusses the strategic planning needs of the KM deployment process, and develops a framework that could be used specifically by engineering firms to guide the KM implementation process.
The future of human resource management
Authors: Aghazadeh Seyed‐Mahmoud
Published: June 2003

Human resource management must change as the business environment in which it operates changes. Outlines the key challenges facing human resources managers as they move from simply handling personnel issues to making a strategic contribution to the future directions and development of an organization. Demonstrates that human resources managers can contribute both to performance enhancement and cost reduction thus contributing directly to the productivity of the organization.
Surveyor variability – application of social judgement theory
Authors: Kempton Jim , Alani Amir , Chapman Keith
Published: June 2003

Surveyor variability has been previously identified as a barrier to the consistency and usability of house condition survey data. This paper explores the use of social judgement theory (SJT) as a potential method to account for, and reduce the impact of, surveyor variability. The study followed the principles of SJT first proposed by Egon Brunswik. The results of the study indicate that the SJT method does have the potential to aid understanding of the survey judgement policy of individual surveyors in terms of the importance they give to building elements and the underlying focus, or theme, of a survey. Knowledge of this policy could be utilised in house condition surveys by recalibration of survey results to take account of a surveyor’s policy. In addition, training requirements for individual surveyors could be identified.
An investigation into home owner maintenance awareness, management and skill‐knowledge enhancing attributes
Authors: Kangwa Joseph , Olubodun JFemi
Published: June 2003

Recent governments have highlighted the problems of unfitness and why individual homeowners should intervene to deal with the maintenance problems of their own homes. Current estimates of the cost of comprehensive renewal are said to run into billions of pounds. There is also a genuine concern that the number of unfit dwellings will continue to increase regardless of the steady pace of renewal programmes. Arguably this concern has greatly influenced the dynamics of primary maintenance attributes of property owners. The primary attributes are recognised to be a product of increased owner‐maintenance awareness; enhanced owner‐maintenance skills and knowledge; and the owner‐maintenance management abilities. These attributes are interwoven, and therefore cannot be left out of current initiatives to improving the backlog of under‐maintenance in the owner‐occupier sector.
Issues of site inspections for fire safety ranking of multi‐storey buildings
Authors: Lo S.M. , Cheng W.Y.
Published: June 2003

Recent fire disasters in Hong Kong and other cities in China show that fire safety should receive more attention. In Hong Kong, a large number of pre‐1980 high‐rise buildings were designed according to old prescriptive building and fire codes. The fire protection measures of these buildings may not be the same as the standard in effect today, even if all fire safety items have been well maintained. Assessment of the fire safety level of these old buildings – on the basis of current prescriptive requirements – may return a conclusion that many buildings’ fire safety systems are “sub‐standard”, and the fire safety level is unacceptably low. However, whether such a conclusion is warranted, thereby triggering immediate improvement action, is debatable, because the rigid prescriptive requirements in the fire codes do not provide a holistic picture of the fire safety level in these buildings. This paper discusses the issues of site inspections for a systematic approach to perform the fire safety ranking for multi‐storey buildings.
Polypropylene fibres in concrete with regard to durability
Authors: Richardson Alan
Published: June 2003

Recent laboratory research has shown that small additions of monofilament polypropylene fibres in concrete, in diameter range of 22 to 35 micron by 19mm long, reduce the flow of water through the concrete matrix by preventing the transmission of water through the normal modes of ingress, e.g. capillaries, pore structure, covercrete, etc. The implications of these qualities in concrete with polypropylene fibre additions is that cement hydration will be improved, separation of aggregate will be reduced and the flow of water through concrete that causes deterioration from freeze/thaw action and rebar corrosion will be reduced, creating an environment in which enhanced durability may take place. As a consequence, lower life cycle costs and best value will be achieved for concrete use, with an ultimate reduction in the cost of maintaining the aging infrastructure. A unique aspect of this work is that heart and covercrete are analysed and compared with corroborative results.
Identifying customer need patterns for customization and personalization
Authors: Du Xuehong , Jiao Jianxin , Tseng Mitchell M.
Published: July 2003

The importance of incorporating customer preferences into product specifications for successful customized product design has been well recognized. An approach based on the identification of customer need patterns is proposed in this paper for better understanding of customer preferences and accordingly to enhance the product definition for customization and personalization. A tree‐structured classification algorithm is formulated for the identification of customer need patterns. Accordingly, a two‐phase methodology is developed for effective product definition. A case study of power supply products is reported to illustrate the feasibility and potential of the proposed approach.
Building enterprise‐wide information supply chains based on the fractal concept
Authors: Walsh Patrick , Koutsakas Philippos , Vontas Apostolos , Koumpis Adamantios
Published: July 2003

Presents work carried out in the wider context of the IST Adrenalin project whose aim is to facilitate formation and lifecycle management of networked enterprises utilising concepts from two key information research areas. The approach described places heavy emphasis on the notion of mobile agent technologies and their adaptation for achieving the IT realisation of the above theoretical background. It covers specification, design and conceptual realisation of how information supply chains and routes can be organised and navigated across networked enterprise activities within the context of a branch independent model. Builds on the distribute and integrate concept as well as on the fractal idea by supporting self‐similarity, self‐organisation, self‐optimisation and dynamic organisational behavior. The harmonised combination of the concepts formulated in the Adrenalin theoretical framework and their IT realisation are employed within the context of a real‐world case study in an industrial ERP system.