bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue Gene Expression Analysis Using Arrayed Normalized cDNA Libraries
Authors: Eickhoff Holger , Schuchhardt Johannes , Ivanov Igor , Meier-Ewert Sebastian , O'Brien John , Malik Arif , Tandon Neeraj , Wolski Eryk-Witold , Rohlfs Elke , Nyarsik Lajos , Reinhardt Richard , Nietfeld Wilfried , Lehrach Hans
Published: July 2002

We have used oligonucleotide-fingerprinting data on 60,000 cDNA clones from two different mouse embryonic stages to establish a normalized cDNA clone set. The normalized set of 5,376 clones represents different clusters and therefore, in almost all cases, different genes. The inserts of the cDNA clones were amplified by PCR and spotted on glass slides. The resulting arrays were hybridized with mRNA probes prepared from six different adult mouse tissues. Expression profiles were analyzed by hierarchical clustering techniques. We have chosen radioactive detection because it combines robustness with sensitivity and allows the comparison of multiple normalized experiments. Sensitive detection combined with highly effective clustering algorithms allowed the identification of tissue-specific expression profiles and the detection of genes specifically expressed in the tissues investigated. The obtained results are publicly available (http://www.rzpd.de) and can be used by other researchers as a digital expression reference.

[The sequence data described in this paper have been submitted to the EMBL data library under accession nos. AL360374–AL36537.]
Identification of New X-Chromosomal Genes Required for Drosophila Oogenesis and Novel Roles for fs(1)Yb, brainiac and dunce
Authors: Swan Andrew , Hijal Sirine , Hilfiker Andres , Suter Beat
Published: July 2002

We performed a screen for female sterile mutations on the X chromosome of Drosophila melanogaster and identified new loci required for developmental events in oogenesis as well as new alleles of previously described genes. We present mapping and phenotypic characterization data for many of these genes and discuss their significance in understanding fundamental developmental and cell biological processes. Our screen has identified genes that are involved in cell cycle control, intracellular transport, cell migration, maintenance of cell membranes, epithelial monolayer integrity and cell survival or apoptosis. We also describe new roles for the genesdunce (dnc), brainiac (brn) andfs(1)Yb, and we identify new alleles of Sex lethal(Sxl), ovarian tumor (otu), sans filles (snf), fs(1)K10, singed(sn), and defective chorion-1 (dec-1).
Comparison of the Small Molecule Metabolic Enzymes of Escherichia coli and Saccharomyces cerevisiae
Authors: Jardine Oliver , Gough Julian , Chothia Cyrus , Teichmann Sarah A.
Published: July 2002

The comparison of the small molecule metabolism pathways inEscherichia coli and Saccharomyces cerevisiae (yeast) shows that 271 enzymes are common to both organisms. These common enzymes involve 384 gene products in E. coli and 390 in yeast, which are between one half and two thirds of the gene products of small molecule metabolism in E. coli and yeast, respectively. The arrangement and family membership of the domains that form all or part of 374 E. coli sequences and 343 yeast sequences was determined. Of these, 70% consist entirely of homologous domains, and 20% have homologous domains linked to other domains that are unique toE. coli, yeast, or both. Over two thirds of the enzymes common to the two organisms have sequence identities between 30% and 50%. The remaining groups include 13 clear cases of nonorthologous displacement. Our calculations show that at most one half to two thirds of the gene products involved in small molecule metabolism are common to E. coli and yeast. We have shown that the common core of 271 enzymes has been largely conserved since the separation of prokaryotes and eukaryotes, including modifications for regulatory purposes, such as gene fusion and changes in the number of isozymes in one of the two organisms. Only one fifth of the common enzymes have nonhomologous domains between the two organisms. Around the common core very different extensions have been made to small molecule metabolism in the two organisms.

[Online supplementary material available a http://www.genome.org.]
Duplications on Human Chromosome 22 Reveal a Novel Ret Finger Protein-Like Gene Family with Sense and Endogenous Antisense Transcripts
Authors: Seroussi Eyal , Kedra Darek , Pan Hua-Qin , Peyrard Myriam , Schwartz Charles , Scambler Peter , Donnai Dian , Roe Bruce A. , Dumanski Jan P.
Published: July 2002

Analysis of 600 kb of sequence encompassing the beta-prime adaptin (BAM22) gene on human chromosome 22 revealed intrachromosomal duplications within 22q12–13 resulting in three active RFPLgenes, two RFPL pseudogenes, and two pseudogenes ofBAM22. The genomic sequence of BAM22ϑ1 shows a remarkable similarity to that of BAM22. The cDNA sequence comparison of RFPL1, RFPL2, and RFPL3 showed 95%–96% identity between the genes, which were most similar to theRet Finger Protein gene from human chromosome 6. The sense RFPL transcripts encode proteins with the tripartite structure, composed of RING finger, coiled–coil, and B30-2 domains, which are characteristic of the RING–B30 family. Each of these domains are thought to mediate protein–protein interactions by promoting homo- or heterodimerization. The MID1 gene on Xp22 is also a member of the RING-B30 family and is mutated in Opitz syndrome (OS). The autosomal dominant form of OS shows linkage to 22q11–q12. We detected a polymorphic protein-truncating allele ofRFPL1 in 8% of the population, which was not associated with the OS phenotype. We identified 6-kb and 1.2-kb noncoding antisense mRNAs of RFPL1S and RFPL3S antisense genes, respectively. The RFPL1S and RFPL3S genes cover substantial portions of their sense counterparts, which suggests that the function of RFPL1S and RFPL3S is a post-transcriptional regulation of the sense RFPLgenes. We illustrate the role of intrachromosomal duplications in the generation of RFPL genes, which were created by a series of duplications and share an ancestor with the RING-B30 domain containing genes from the major histocompatibility complex region on human chromosome 6.

[The sequence data described in this paper have been submitted to GenBank under the following accession nos:AJ010228–AJ010233, AC000025, AC000041, AC000045, and AC002059.]
Isolation of Mutations Affecting the Development of Freezing Tolerance in Arabidopsis thaliana (L.) Heynh
Authors: Warren G. , McKown R. , Marin A. , Teutonico R.
Published: July 2002

We screened for mutations deleterious to the freezing tolerance of Arabidopsis thaliana (L.) Heynh. ecotype Columbia. Tolerance was assayed by the vigor and regrowth of intact plants after cold acclimation and freezing. From a chemically mutagenized population, we obtained 13 lines of mutants with highly penetrant phenotypes. In 5 of these, freezing sensitivity was attributable to chilling injury sustained during cold acclimation, but in the remaining 8 lines, the absence of injury prior to freezing suggested that they were affected specifically in the development of freezing tolerance. In backcrosses, freezing sensitivity from each line segregated as a single nuclear mutation. Complementation tests indicated that the 8 lines contained mutations in 7 different genes. The mutants' freezing sensitivity was also detectable in the leakage of electrolytes from frozen leaves. However, 1 mutant line that displayed a strong phenotype at the whole-plant level showed a relatively weak phenotype by the electrolyte leakage assay.
Genetic Transformation, Recovery, and Characterization of Fertile Soybean Transgenic for a Synthetic Bacillus thuringiensis cryIAc Gene
Authors: Stewart Jr C. N. , Adang M. J. , All J. N. , Boerma H. R. , Cardineau G. , Tucker D. , Parrott W. A.
Published: July 2002

Somatic embryos of Jack, a Glycine max (L.) Merrill cultivar, were transformed using microprojectile bombardment with a synthetic Bacillus thuringiensis insecticidal crystal protein gene (Bt cryIAc) driven by the 35S promoter and linked to the HPH gene. Approximately 10 g of tissue was bombarded, and three transgenic lines were selected on hygromycin-containing media and converted into plants. The recovered lines contained the HPH gene, but the Bt gene was lost in one line. The plasmid was rearranged in the second line, and the third line had two copies, one of which was rearranged. The CryIAc protein accumulated up to 46 ng mg-1 extractable protein. In detached-leaf bioassays, plants with an intact copy of the Bt gene, and to a lesser extent those with the rearranged copy, were protected from damage from corn earworm (Helicoverpa zea), soybean looper (Pseudoplusia includens), tobacco bud-worm (Heliothis virescens), and velvetbean caterpillar (Anticarsia gemmatalis). Corn earworm produced less than 3% defoliation on transgenic plants, compared with 20% on the lepidopteran-resistant breeding line GatIR81–296, and more than 40% on susceptible cultivars. Unlike previous reports of soybean transformation using this technique, all plants were fertile. To our knowledge, this is the first report of a soybean transgenic for a highly expressed insecticidal gene.
Identification of a 1-Aminocyclopropane-1-Carboxylic Acid Synthase Gene Linked to the Female (F) Locus That Enhances Female Sex Expression in Cucumber
Authors: Trebitsh T. , Staub J. E. , O'Neill S. D.
Published: July 2002

Sex determination in cucumber (Cucumis sativus L.) is controlled largely by three genes: F, m, and a. The F and m loci interact to produce monoecious (M_f_) or gynoecious (M_F_) sex phenotypes. Ethylene and factors that induce ethylene biosynthesis, such as 1-aminocyclopropane-1-carboxylate (ACC) and auxin, also enhance female sex expression. A genomic sequence (CS-ACS1) encoding ACC synthase was amplified from genomic DNA by a polymerase chain reaction using degenerate oligonucleotide primers. Expression of CS-ACS1 is induced by auxin, but not by ACC, in wounded and intact shoot apices. Southern blot hybridization analysis of near-isogneic gynoecious (MMFF) and monoecious (MMff) lines derived from diverse genetic backgrounds revealed the existence of an additional ACC synthase (CS-ACS1G) genomic sequence in the gynoecious lines. Sex phenotype analysis of a segregating F2 population detected a 100% correlation between the CS-ACS1G marker and the presence of the F locus. The CS-ACS1G gene is located in linkage group B coincident with the F locus, and in the population tested there was no recombination between the CS-ACS1G gene and the F locus. Collectively, these data suggest that CS-ACS1G is closely linked to the F locus and may play a pivotal role in the determination of sex in cucumber flowers.
Effects of Sulfanilamide and Methotrexate on 13C Fluxes through the Glycine Decarboxylase/Serine Hydroxymethyltransferase Enzyme System in Arabidopsis1
Authors: Prabhu Vikram , Brock Chatson K. , Lui Helen , Abrams Garth D. , King John
Published: July 2002

In C3 plants large amounts of photorespiratory glycine (Gly) are converted to serine by the tetrahydrofolate (THF)-dependent activities of the Gly decarboxylase complex (GDC) and serine hydroxymethyltransferase (SHMT). Using 13C nuclear magnetic resonance, we monitored the flux of carbon through the GDC/SHMT enzyme system in Arabidopsis thaliana (L.) Heynh. Columbia exposed to inhibitors of THF-synthesizing enzymes. Plants exposed for 96 h to sulfanilamide, a dihydropteroate synthase inhibitor, showed little reduction in flux through GDC/SHMT. Two other sulfonamide analogs were tested with similar results, although all three analogs competitively inhibited the partially purified enzyme. However, methotrexate or aminopterin, which are confirmed inhibitors of Arabidopsis dihydrofolate reductase, decreased the flux through the GDC/SHMT system by 60% after 48 h and by 100% in 96 h. The uptake of [α-13C]Gly was not inhibited by either drug class. The specificity of methotrexate action was shown by the ability of 5-formyl-THF to restore flux through the GDC/SHMT pathway in methotrexate-inhibited plants. The experiments with sulfonamides strongly suggest that the mitochondrial THF pool has a long half-life. The studies with methotrexate support the additional, critical role of dihydrofolate reductase in recycling THF oxidized in thymidylate synthesis.
Effects of Oxygen on Nodule Physiology and Expression of Nodulins in Alfalfa1
Authors: Wycoff Keith L. , Hunt Stephen , Gonzales Michael B. , VandenBosch Kathryn A. , Layzell David B. , Hirsch Ann M.
Published: July 2002

Early nodulin 2 (ENOD2) transcripts and protein are specifically found in the inner cortex of legume nodules, a location that coincides with the site of a barrier to O2 diffusion. The extracellular glycoprotein that binds the monoclonal antibody MAC236 has also been localized to this site. Thus, it has been proposed that these proteins function in the regulation of nodule permeability to O2diffusion. It would then be expected that the levels of ENOD2 mRNA/protein and MAC236 antigen would differ in nodules with different permeabilities to O2. We examined the expression of ENOD2 and other nodule-expressed genes in Rhizobium meliloti-induced alfalfa nodules grown under 8, 20, or 50% O2. Although there was a change in the amount of MAC236 glycoprotein, the levels of ENOD2 mRNA and protein did not differ significantly among nodules grown at the different [O2], suggesting that neither ENOD2 transcription nor synthesis is involved in the long-term regulation of nodule permeability. Moreover, although nodules from all treatments reduced their permeability to O2 as the partial pressure of O2(pO2) was increased to 100%, the levels of extractable ENOD2 and MAC236 proteins did not differ from those measured at the growth pO2, further suggesting that if these proteins are involved in a short-term regulation of the diffusion barrier, they must be involved in a way that does not require increased transcription or protein synthesis.
Detection of Ca2+-Dependent Transglutaminase Activity in Root and Leaf Tissue of Monocotyledonous and Dicotyledonous Plants
Authors: Lilley Graham R. , Skill James , Griffin Martin , Bonner Philip L.R.
Published: July 2002

Protein extracted from root and leaf tissue of the dicotyledonous plants pea (Pisum sativum) and broad bean (Vicia faba) and the monocotyledonous plants wheat (Triticum aestivum) and barley (Hordeum vulgare) were shown to catalyze the incorporation of biotin-labeled cadaverine into microtiter-plate-boundN′,N′-dimethylcasein and the cross-linking of biotin-labeled casein to microtiter-plate-bound casein in a Ca2+-dependent manner. The cross-linking of biotinylated casein and the incorporation of biotin-labeled cadaverine into N′,N′-dimethylcasein were time-dependent reactions with a pH optimum of 7.9. Transglutaminase activity was shown to increase over a 2-week growth period in both the roots and leaves of pea. The product of transglutaminase's protein-cross-linking activity, ε-(γ-glutamyl)-lysine isodipeptide, was detected in root and shoot protein from pea, broad bean, wheat, and barley by cation-exchange chromatography. The presence of the isodipeptide was confirmed by reversed-phase chromatography. Hydrolysis of the isodipeptide after cation-exchange chromatography confirmed the presence of glutamate and lysine.
Protein Changes in Response to Progressive Water Deficit in Maize1
Authors: Riccardi Frédérique , Gazeau Pascale , de Vienne Dominique , Zivy Michel
Published: July 2002

Three-week-old plants of two unrelated lines of maize (Zea mays L.) and their hybrid were submitted to progressive water stress for 10 d. Changes induced in leaf proteins were studied by two-dimensional electrophoresis and quantitatively analyzed using image analysis. Seventy-eight proteins out of a total of 413 showed a significant quantitative variation (increase or decrease), with 38 of them exhibiting a different expression in the two genotypes. Eleven proteins that increased by a factor of 1.3 to 5 in stressed plants and 8 proteins detected only in stressed plants were selected for internal amino acid microsequencing, and by similarity search 16 were found to be closely related to previously reported proteins. In addition to proteins already known to be involved in the response to water stress (e.g. RAB17 [Responsive to ABA]), several enzymes involved in basic metabolic cellular pathways such as glycolysis and the Krebs cycle (e.g. enolase and triose phosphate isomerase) were identified, as well as several others, including caffeate O-methyltransferase, the induction of which could be related to lignification.
Cutin Monomers and Surface Wax Constituents Elicit H2O2 in Conditioned Cucumber Hypocotyl Segments and Enhance the Activity of Other H2O2Elicitors1
Authors: Fauth Markus , Schweizer Patrick , Buchala Antony , Markstädter Claus , Riederer Markus , Kato Tadahiro , Kauss Heinrich
Published: July 2002

Hypocotyls from etiolated cucumber (Cucumis sativus L.) seedlings were gently abraded at their epidermal surface and cut segments were conditioned to develop competence for H2O2 elicitation. Alkaline hydrolysates of cutin from cucumber, tomato, and apple elicited H2O2 in such conditioned segments. The most active constituent of cucumber cutin was identified as dodecan-1-ol, a novel cutin monomer capable of forming hydrophobic terminal chains. Additionally, the cutin hydrolysates enhanced the activity of a fungal H2O2 elicitor, similar to cucumber surface wax, which contained newly identified alkan-1,3-diols. The specificity of elicitor and enhancement activity was further elaborated using some pure model compounds. Certain saturated hydroxy fatty acids were potent H2O2 elicitors as well as enhancers. Some unsaturated epoxy and hydroxy fatty acids were also excellent H2O2 elicitors but inhibited the fungal elicitor activity. Short-chain alkanols exhibited good elicitor and enhancer activity, whereas longer-chain alkan-1-ols were barely active. The enhancement effect was also observed for H2O2 elicitation by ergosterol and chitosan. The physiological significance of these observations might be that once the cuticle is degraded by fungal cutinase, the cutin monomers may act as H2O2 elicitors. Corrosion of cutin may also bring surface wax constituents in contact with protoplasts and enhance elicitation.
Source and Magnitude of Ammonium Generation in Maize Roots
Authors: Feng Jinan , Volk Richard J. , Jackson William A.
Published: July 2002

Studies with 15N indicate that appreciable generation of NH4  + from endogenous sources accompanies the uptake and assimilation of exogenous NH4  + by roots. To identify the source of NH4  +generation, maize (Zea mays L.) seedlings were grown on14NH4  + and then exposed for 3 d to highly labeled 15NH4  +. More of the entering 15NH4  + was incorporated into the protein-N fraction of roots in darkness (approximately 25%) than in the light (approximately 14%). Although the 14NH4  + content of roots declined rapidly to less than 1 μmol per plant, efflux of14NH4  + continued throughout the 3-d period at an average daily rate of 14 μmol per plant. As a consequence, cumulative 14NH4  +efflux during the 3-d period accounted for 25% of the total14N initially present in the root. Although soluble organic14N in roots declined during the 3-d period, insoluble14N remained relatively constant. In shoots both soluble organic 14N and 14NH4  +declined, but a comparable increase in insoluble 14N was noted. Thus, total 14N in shoots remained constant, reflecting little or no net redistribution of 14N between shoots and roots. Collectively, these observations reveal that catabolism of soluble organic N, not protein N, is the primary source of endogenous NH4  + generation in maize roots.
Nucellain, a Barley Homolog of the Dicot Vacuolar-Processing Protease, Is Localized in Nucellar Cell Walls
Authors: Linnestad Casper , Doan Danny N.P. , Brown Roy C. , Lemmon Betty E. , Meyer David J. , Jung Rudolf , Olsen Odd-Arne
Published: July 2002

The nucellus is a complex maternal grain tissue that embeds and feeds the developing cereal endosperm and embryo. Differential screening of a barley (Hordeum vulgare) cDNA library from 5-d-old ovaries resulted in the isolation of two cDNA clones encoding nucellus-specific homologs of the vacuolar-processing enzyme of castor bean (Ricinus communis). Based on the sequence of these barley clones, which are called nucellains, a homolog from developing corn (Zea mays) grains was also identified. In dicots the vacuolar-processing enzyme is believed to be involved in the processing of vacuolar storage proteins. RNA-blot and in situ-hybridization analyses detected nucellain transcripts in autolysing nucellus parenchyma cells, in the nucellar projection, and in the nucellar epidermis. No nucellain transcripts were detected in the highly vacuolate endosperm or in the other maternal tissues of developing grains such as the testa or the pericarp. Using an antibody raised against castor bean vacuolar-processing protease, a single polypeptide was recognized in protein extracts from barley grains. Immunogold-labeling experiments with this antibody localized the nucellain epitope not in the vacuoles, but in the cell walls of all nucellar cell types. We propose that nucellain plays a role in processing and/or turnover of cell wall proteins in developing cereal grains.
Inhibitory Regulation of Higher-Plant Myosin by Ca2+Ions1
Authors: Yokota Etsuo , Muto Shoshi , Shimmen Teruo
Published: July 2002

Myosin isolated from the pollen tubes of lily (Lilium longiflorum) is composed of a 170-kD heavy chain (E. Yokota and T. Shimmen [1994] Protoplasma 177: 153–162). Both the motile activity in vitro and the F-actin-stimulated ATPase activity of this myosin were inhibited by Ca2+ at concentrations higher than 10−6m. In the Ca2+ range between 10−6 and 10−5m, inhibition of the motile activity was reversible. In contrast, inhibition by more than 10−5m Ca2+ was not reversible upon Ca2+removal. An 18-kD polypeptide that showed the same mobility in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as that of spinach calmodulin (CaM) was present in this myosin fraction. This polypeptide showed a mobility shift in sodium dodecyl sulfate-polyacrylamide gel electrophoresis in a Ca2+-dependent manner. Furthermore, this polypeptide was recognized by antiserum against spinach CaM. By immunoprecipitation using antiserum against the 170-kD heavy chain, the 18-kD polypeptide was coprecipitated with the 170-kD heavy chain, provided that the Ca2+ concentration was low, indicating that this 18-kD polypeptide is bound to the 170-kD myosin heavy chain. However, the 18-kD polypeptide was dissociated from the 170-kD heavy chain at high Ca2+ concentrations, which irreversibly inhibited the motile activity of this myosin. From these results, it is suggested that the 18-kD polypeptide, which is likely to be CaM, is associated with the 170-kD heavy chain as a light chain. It is also suggested that this polypeptide is involved in the regulation of this myosin by Ca2+. This is the first biochemical basis, to our knowledge, for Ca2+ regulation of cytoplasmic streaming in higher plants.
Regulation of S-Like Ribonuclease Levels in Arabidopsis. Antisense Inhibition of RNS1 orRNS2 Elevates Anthocyanin Accumulation1
Authors: Bariola Pauline A. , MacIntosh Gustavo C. , Green Pamela J.
Published: July 2002

The S-like ribonucleases (RNases) RNS1 and RNS2 of Arabidopsis are members of the widespread T2 ribonuclease family, whose members also include the S-RNases, involved in gametophytic self-incompatibility in plants. Both RNS1 andRNS2 mRNAs have been shown previously to be induced by inorganic phosphate (Pi) starvation. In our study we examined this regulation at the protein level and determined the effects of diminishing RNS1 and RNS2 expression using antisense techniques. The Pi-starvation control of RNS1 and RNS2 was confirmed using antibodies specific for each protein. These specific antibodies also demonstrated that RNS1 is secreted, whereas RNS2 is intracellular. By introducing antisense constructs, mRNA accumulation was inhibited by up to 90% for RNS1 and up to 65% for RNS2. These plants contained abnormally high levels of anthocyanins, the production of which is often associated with several forms of stress, including Pi starvation. This effect demonstrates that diminishing the amounts of either RNS1 or RNS2 leads to effects that cannot be compensated for by the actions of other RNases, even though Arabidopsis contains a large number of different RNase activities. These results, together with the differential localization of the proteins, imply that RNS1 and RNS2 have distinct functions in the plant.
Symbiotic Root Nodules of the Actinorhizal PlantDatisca glomerata Express Rubisco Activase mRNA1
Authors: Okubara Patricia A. , Pawlowski Katharina , Murphy Terence M. , Berry Alison M.
Published: July 2002

N2-fixing symbiotic root nodules of the actinorhizal host Datisca glomerata express Dgrca(D.glomerataRubisco activase) mRNA, a transcript usually associated with photosynthetic organs or tissues. In northern blots a mature, 1700-nucleotide Dgrca mRNA was detected in green plant organs (leaves, flowers, and developing fruits) and in nodules but was not detected in roots. A second message of 3000 nucleotides was observed only in nodules. Both size classes of transcripts were polyadenylated. The larger transcript was 2- to 5-fold more abundant than the mature mRNA; it was hybridized to an intronic probe, indicating that a stable, incompletely spliced transcript was accumulating. Treatment with light on excised nodules did not alter the relative abundance of the two species. In in situ hybridizations theDgrca message was expressed intensely in the nuclei of infected cells. The Dgrca transcripts also accumulated at lower levels in uninfected cortical cells adjacent to the periderm and the vascular cylinder. mRNA encoding the large subunit of Rubisco (DgrbcL) was abundant in mature infected cells and in the amyloplast-rich sheath of uninfected cortical cells lying between the infected cells and nodule periderm. The proteins Rubisco activase, Rubisco, and the 33-kD O2-evolving complex subunit did not accumulate to detectable levels, indicating that a functional photosynthetic apparatus was not prevalent in nodule tissue. Signals or factors required for the transcription of Dgrca appeared to be present in nodules, but efficient splicing and translation of the message were not observed in Frankia-infected tissue where transcript accumulation was highest.
Influence of White Clover Mosaic Potexvirus Infection on the Endogenous Cytokinin Content of Bean
Authors: Clarke Sean Francis , McKenzie Marian Jane , Burritt David John , Guy Paul Leslie , Jameson Paula Elizabeth
Published: July 2002

The cytokinin content in the primary leaves of bean (Phaseolus vulgaris) was monitored for 10 d after inoculation with white clover mosaic potexvirus. The cytokinins were isolated, purified, separated by high-performance liquid chromatography, and quantified by radioimmunoassay. The cytokinins detected at the time of inoculation (d 0) were: (a) the free bases, zeatin (Z), dihydrozeatin (DZ), and isopentenyladenine; (b) the riboside, DZ riboside (DZR); (c) theO-glucosides of DZ, DZR, and Z riboside; (d) the nucleotides, Z riboside-5′-monophosphate and isopentenyladenosine-5′-monophosphate; and (e) trace amounts of Z-9-glucoside and DZ-9-glucoside. During the 10 d after inoculation with white clover mosaic potexvirus, marked quantitative changes in this cytokinin profile were observed. The concentration of the free bases and DZR decreased, accompanied by an increase in the 9-glucosides and the nucleotides. Virus titer increased rapidly 3 d after inoculation, attaining a maximum level at d 5. This increase coincided with the increases in the 9-glucosides and the nucleotides. We propose that the decline in the cytokinin free bases and riboside may allow the increase of virus titer in bean and lead to the senescence of infected leaves.
Expression and Localization of Nitrilase during Symptom Development of the Clubroot Disease in Arabidopsis
Authors: Grsic-Rausch Slobodanka , Kobelt Peter , Siemens Johannes M. , Bischoff Markus , Ludwig-Müller Jutta
Published: July 2002

The expression of nitrilase in Arabidopsis during the development of the clubroot disease caused by the obligate biotroph Plasmodiophora brassicae was investigated. A time course study showed that only during the exponential growth phase of the clubs was nitrilase prominently enhanced in infected roots compared with controls.NIT1 and NIT2 are the nitrilase isoforms predominantly expressed in clubroot tissue, as shown by investigating promoter-β-glucuronidase fusions of each. Two peaks of β-glucuronidase activity were visible: an earlier peak (21 d post inoculation) consisting only of the expression of NIT1, and a second peak at about 32 d post inoculation, which predominantly consisted of NIT2 expression. Using a polyclonal antibody against nitrilase, it was shown that the protein was mainly found in infected cells containing sporulating plasmodia, whereas in cells of healthy roots and in uninfected cells of inoculated roots only a few immunosignals were detected. To determine which effect a missing nitrilase isoform might have on symptom development, theP. brassicae infection in a nitrilase mutant (nit1-3) of Arabidopsis was investigated. As a comparison, transgenic plants overexpressing NIT2 under the control of the cauliflower mosaic virus 35S promoter were studied. Root galls were smaller in nit1-3 plants compared with the wild type. The phenotype of smaller clubs in the mutant was correlated with a lower free indole-3-acetic acid content in the clubs compared with the wild type. Overexpression of nitrilase did not result in larger clubs compared with the wild type. The putative role of nitrilase and auxins during symptom development is discussed.
Metabolic Dysfunction and Unabated Respiration Precede the Loss of Membrane Integrity during Dehydration of Germinating Radicles
Authors: Leprince Olivier , Harren Frans J.M. , Buitink Julia , Alberda Mark , Hoekstra Folkert A.
Published: July 2002

This study shows that dehydration induces imbalanced metabolism before loss of membrane integrity in desiccation-sensitive germinated radicles. Using a photoacoustic detection system, responses of CO2 emission and fermentation to drying were analyzed non-invasively in desiccation-tolerant and -intolerant radicles of cucumber (Cucumis sativa) and pea (Pisum sativum). Survival after drying and a membrane integrity assay showed that desiccation tolerance was present during early imbibition and lost in germinated radicles. However, tolerance could be re-induced in germinated cucumber radicles by incubation in polyethylene glycol before drying. Tolerant and polyethylene glycol (PEG)-induced tolerant radicles exhibited a much-reduced CO2 production before dehydration compared with desiccation-sensitive radicles. This difference was maintained during dehydration. In desiccation-sensitive tissues, dehydration induced an increase in the emission of acetaldehyde and ethanol that peaked well before the loss of membrane integrity. Acetaldehyde emission from sensitive radicles was significantly reduced when dehydration occurred in 50% O2instead of air. Acetaldehyde/ethanol were not detected in dehydrating tolerant radicles of either species or in polyethylene glycol-induced tolerant cucumber radicles. Thus, a balance between down-regulation of metabolism during drying and O2 availability appears to be associated with desiccation tolerance. Using Fourier transform infrared spectroscopy, acetaldehyde was found to disturb the phase behavior of phospholipid vesicles, suggesting that the products resulting from imbalanced metabolism in seeds may aggravate membrane damage induced by dehydration.
Purification, Characterization, and Molecular Cloning of the Gene of a Seed-Specific Antimicrobial Protein from Pokeweed
Authors: Liu Yingfang , Luo Jingchu , Xu Chunyu , Ren Fucheng , Peng Cheng , Wu Guangyao , Zhao Jindong
Published: July 2002

A small cysteine-rich protein with antimicrobial activity was isolated from pokeweed (Phytolacca americana) seeds and purified to homogeneity. The protein inhibits the growth of several filamentous fungi and gram-positive bacteria. The protein was highly basic, with a pI higher than 10. The entire amino acid sequence of the protein was determined to be homologous to antimicrobial protein (AMP) from Mirabilis jalapa. The cDNA encoding the P. americana AMP (Pa-AMP-1) and chromosomal DNA containing the gene were cloned and sequenced. The deduced amino acid sequence shows the presence of a signal peptide at the amino terminus, suggesting that the protein is synthesized as a preprotein and secreted outside the cells. The chromosomal gene shows the presence of an intron located within the region encoding the signal peptide. Southern hybridization showed that there was small gene family encoding Pa-AMP. Immunoblotting showed that Pa-AMP-1 was only present in seeds, and was absent in roots, leaves, and stems. The Pa-AMP-1 protein was secreted into the environment of the seeds during germination, and may create an inhibitory zone against soil-borne microorganisms. The disulfide bridges of Pa-AMP-1 were identified. The three-dimensional modeling of Pa-AMP-1 indicates that the protein has a small cystine-knot folding, a positive patch, and a hydrophobic patch.
A New Protein Phosphatase 2C (FsPP2C1) Induced by Abscisic Acid Is Specifically Expressed in Dormant Beechnut Seeds
Authors: Lorenzo Oscar , Rodrı́guez Dolores , Nicolás Gregorio , Rodrı́guez Pedro L. , Nicolás Carlos
Published: July 2002

An abscisic acid (ABA)-induced cDNA fragment encoding a putative protein phosphatase 2C (PP2C) was obtained by means of differential reverse transcriptase-polymerase chain reaction approach. The full-length clone was isolated from a cDNA library constructed using mRNA from ABA-treated beechnut (Fagus sylvatica) seeds. This clone presents all the features of plant type PP2C and exhibits homology to members of this family such as AthPP2CA (61%), ABI1 (48%), or ABI2 (47%), therefore it was named FsPP2C1. The expression of FsPP2C1 is detected in dormant seeds and increases after ABA treatment, when seeds are maintained dormant, but it decreases and tends to disappear when dormancy is being released by stratification or under gibberellic acid treatment. Moreover, drought stress seems to have no effect on FsPP2C1 transcript accumulation. The FsPP2C1 transcript expression is tissue specific and was found to accumulate in ABA-treated seeds rather than in other ABA-treated vegetative tissues examined. These results suggest that the corresponding protein could be related to ABA-induced seed dormancy. By expressing FsPP2C1 inEscherichia coli as a histidine tag fusion protein, we have obtained direct biochemical evidence supporting Mg2+-dependent phosphatase activity of this protein.
Sugar-Binding Activity of Pea Lectin Enhances Heterologous Infection of Transgenic Alfalfa Plants by Rhizobium leguminosarum biovar viciae
Authors: van Rhijn Pieternel , Fujishige Nancy A. , Lim Pyung Ok , Hirsch Ann M.
Published: July 2002

Transgenic alfalfa (Medicago sativa L. cv Regen) roots carrying genes encoding soybean lectin or pea (Pisum sativum) seed lectin (PSL) were inoculated withBradyrhizobium japonicum or Rhizobium leguminosarum bv viciae, respectively, and their responses were compared with those of comparably inoculated control plants. We found that nodule-like structures formed on alfalfa roots only when the rhizobial strains produced Nod factor from the alfalfa-nodulating strain, Sinorhizobium meliloti. Uninfected nodule-like structures developed on the soybean lectin-transgenic plant roots at very low inoculum concentrations, but bona fide infection threads were not detected even when B. japonicum produced the appropriate S. melilotiNod factor. In contrast, the PSL-transgenic plants were not only well nodulated but also exhibited infection thread formation in response toR. leguminosarum bv viciae, but only when the bacteria expressed the complete set of S. meliloti nod genes. A few nodules from the PSL-transgenic plant roots were even found to be colonized by R. leguminosarum bvviciae expressing S. meliloti nod genes, but the plants were yellow and senescent, indicating that nitrogen fixation did not take place. Exopolysaccharide appears to be absolutely required for both nodule development and infection thread formation because neither occurred in PSL-transgenic plant roots following inoculation with an Exo−  R. leguminosarumbv viciae strain that produced S. meliloti Nod factor.
Brassinosteroid-6-Oxidases from Arabidopsis and Tomato Catalyze Multiple C-6 Oxidations in Brassinosteroid Biosynthesis
Authors: Shimada Yukihisa , Fujioka Shozo , Miyauchi Narumasa , Kushiro Masayo , Takatsuto Suguru , Nomura Takahito , Yokota Takao , Kamiya Yuji , Bishop Gerard J. , Yoshida Shigeo
Published: July 2002

Brassinosteroids (BRs) are steroidal plant hormones that are essential for growth and development. It has been proposed that BRs are synthesized via two parallel pathways, the early and late C-6 oxidation pathways according to the C-6 oxidation status. The tomato (Lycopersicon esculentum) Dwarf gene encodes a cytochrome P450 that has been shown to catalyze the C-6 oxidation of 6-deoxocastasterone to castasterone. We isolated an Arabidopsis ortholog (AtBR6ox gene) of the tomatoDwarf gene. The encoded polypeptide has characteristics of P450s and is classified into the CYP85 family. TheAtBR6ox and tomato Dwarf gene were expressed in yeast and the ability of the transformed yeast cells to metabolize 6-deoxo-BRs was tested. Metabolites were analyzed by gas chromatography-mass spectrometry. Both enzymes catalyze multiple steps in BR biosynthesis: 6-deoxoteasterone to teasterone, 3-dehydro-6-deoxoteasterone to 3-dehydroteasterone, 6-deoxotyphasterol to typhasterol, and 6-deoxocastasterone to castasterone. Our results indicate that the AtBR6ox gene and the tomatoDwarf gene encode steroid-6-oxidases and that these enzymes have a broad substrate specificity. This suggests that the BR biosynthetic pathway consists of a metabolic grid rather than two separate parallel pathways.
The Wheat cDNA LCT1 Generates Hypersensitivity to Sodium in a Salt-Sensitive Yeast Strain
Authors: Amtmann Anna , Fischer Marc , Marsh Ellen L. , Stefanovic Aleksandra , Sanders Dale , Schachtman Daniel P.
Published: July 2002

Salinity affects large areas of agricultural land, and all major crop species are intolerant to high levels of sodium ions. The principal route for Na+ uptake into plant cells remains to be identified. Non-selective ion channels and high-affinity potassium transporters have emerged as potential pathways for Na+entry. A third candidate for Na+ transport into plant cells is a low-affinity cation transporter represented by the wheat protein LCT1, which is known to be permeable for a wide range of cations when expressed in yeast (Saccharomyces cerevisiae). To investigate the role of LCT1 in salt tolerance we have used the yeast strain G19, which is disrupted in the genes encoding Na+export pumps and as a result displays salt sensitivity comparable with wheat. After transformation with LCT1, G19 cells became hypersensitive to NaCl. We show that LCT1 expression results in a strong decrease of intracellular K+/Na+ ratio in G19 cells due to the combined effect of enhanced Na+ accumulation and loss of intracellular K+. Na+ uptake through LCT1 was inhibited by K+ and Ca2+ at high concentrations and the addition of these ions rescued growth ofLCT1-transformed G19 on saline medium. LCT1 was also shown to mediate the uptake of Li+ and Cs+. Expression of two mutant LCT1 cDNAs with N-terminal truncations resulted in decreased Ca2+ uptake and increased Na+ tolerance compared with expression of the full-lengthLCT1. Our findings strongly suggest thatLCT1 represents a molecular link between Ca2+ and Na+ uptake into plant cells.
Shot peening
Authors: Kirk David
Published: July 2002

Discusses the use of a corporate Internet in a geographically‐spread consulting firm, James Martin & Co., to share ideas, vision, client information and results. Illustrates with examples. Applications include a quarterly Employee Attitude Survey and regular discussion forums. Proposes that a well‐designed corporate intranet is a highly effective method of making intangible vision and mission pledges more tangible.
A fuzzy approach to model RISK of MIC in a cathodically‐protected pipe
Authors: Javaherdashti Reza
Published: July 2002

Microbiologically‐influenced corrosion (MIC) is a type of corrosion in which, by its nature, many uncertainties exist. Using fuzzy logic, two models of MIC are modified to define a fuzzy set of risk of MIC in conditionally‐protected pipes.
Viewpoint: the story so far
Authors: Turner Alan
Published: July 2002

Modern food law can trace its roots back to the late nineteenth century when the Adulteration of Food and Drink Act 1860 was introduced. Since then the legislation has developed and evolved, often in response to specific incidents where an apparently insignificant change to a process or recipe has impacted on food safety. Progressively, controls on food standards and labelling were developed and introduced, the pace quickening from about 1950 onwards. Controls from the 1970s have had to be harmonised across the European Community. Recent concerns over food safety have involved food irradiation and genetic modification. Assurances from experts about the safety of these processes have not entirely satisfied consumers, with the result that labelling has been an important piece of the regulatory jigsaw in these cases. Labelling is also to the fore in the current debate on functional foods. These, and other, issues command the attention of the government’s advisory bodies, in particular the Food Advisory Committee. The regulatory process must become more open and allow public participation if government and expert committees are to win and retain the confidence of the consuming public.
Action learning in management education
Authors: O’Hara Suzanne , Webber Trix , Reeve Steve
Published: July 2002

Provides a definition of the purpose and role of action learning (AL) in management education. Gives examples of programmes in a university business school strongly committed to action learning and outlines some of the benefits of this approach for individuals. Acknowledges that AL is less straightforward and more demanding than a traditional taught programme but potentially could achieve a much wider range of learning outcomes.
Training in Germany: a view from abroad
Authors: Shackleton J.R.
Published: July 2002

Introduces the concept of non‐company‐based vocational training in Germany and assesses the impact of vocational training without work experience. Provides primary research results drawn from a representative survey of eastern German trainees in company and non‐company‐based training. Highlights the importance associated with real work experiences and critically examines the attempts by German labour market authorities to introduce apprenticeship training by providing a state‐funded alternative.
Observations on training and management development in the People’s Republic of China
Authors: Branine Mohamed
Published: July 2002

Gives an eye‐witness account of how training and management development policies are put into practice in Chinese state‐owned enterprises. Makes observations on how training is perceived and implemented in a period of rapid economic change. Also discusses the contribution that western countries could make and the obstacles that could be met, as a result. Draws evidence for these observations from the author’s involvement in a major United Nations Development Programme (UNDP) for the design and teaching of management strategy and human resource management courses to cohorts of managers from selected Chinese foreign trade corporations (FTCs). Asserts that, despite much effort being made to train and develop as many managers as possible, there is still an urgent need for appropriate management training programmes that could meet the quest for skilful and efficient managers who would be able to cope with the managerial demands of increasing economic reforms. Argues, therefore, that there is a gap between the abilities and the process of developing Chinese managers on the one hand and what is required from them for exploiting the economic reform on the other. The process of introducing and implementing training programmes in the People’s Republic of China is characterized by a clear emphasis on quantitative rather than qualitative knowledge and by a poor appreciation of training priorities, because of the way in which management is perceived and managers are controlled.
The profitability of investments in work life‐oriented rehabilitation
Authors: Johanson Ulf
Published: July 2002

Suggests that this study may be recognized as a contribution to the lack of economic evaluations of investments in health promotion programmes. Also contributes to the evaluation of the Swedish work life experiment in the beginning of the 1990s, and the establishment of the Swedish Work Life Fund (SWLF). States that perceptions of the profitability of investments in work life‐oriented rehabilitation, including changes in work organization, changes in work methods and competence development, were investigated in 108 randomly selected organizations. The findings indicate that the investments, which were partly financed by grants from the SWLF, contributed to a reduction in sick‐leave and an increase in productivity. The median value of the pay‐back period was estimated to be 3.0 years. Public organizations, a considerable number of employees, a high percentage of women employees, a significant reduction in sick‐leave and an ongoing organizational change, are some of the characteristics of investments with a short pay‐back period. Concludes that the findings further indicate that grants from the SWLF were an important factor in the initial implementation of investments.
Leadership and local structures in the Amazon region
Authors: Capriles Ruth
Published: July 2002

The occasion of globalization mobilizes internal forces and local leaders into using external forces, allying with alien (national and global) actors to achieve local goals; and letting themselves being used by alien interests and made part of global goals. In the Amazons region, particularly, there has been an emergence of local actors and space‐time structures that deserve attention when devising viable structures in the global world. In this paper, our purpose is to watch some of the actors that interact in the region and learn how, underneath globalization, history depends much on the leaders of local projects. Looks at two modalities: one in Brazil and one in Venezuela.
Audi moves forward with all‐aluminium cars
Authors: Kochan Anna
Published: July 2002

Reviews the all‐aluminium space frame structure of the new Audi A2, describes the techniques used in the body‐in‐white shop, and outlines trim and final assembly operations.