bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methyl jasmonate vapor increases the developmentally controlled synthesis of alkaloids in Catharanthus and Cinchona seedlings
Authors: Aerts Rob J. , Gisi Daniel , De Carolis Emidio , De Luca Vincenzo , Baumann Thomas W. 
Published: November 2004

SummaryShortly after germination, alkaloids are rapidly synthesized in seedlings of both Catharanthus roseus L.G. Don and Cinchona ledgeriana Moens. The effect of low‐level, atmospheric methyl jasmonate on this developmentally controlled process was studied. In both species, about 1 p.p.m. of methyl jasmonate vapor significantly enhanced alkaloid synthesis during germination, resulting in a doubling of alkaloid content in seedlings. Treatment with methyl jasmonate resulted in increased allocation of alkaloid precursors and in enhanced enzyme activities in alkaloid biosynthesis. The ability of methyl jasmonate to increase alkaloid biosynthesis decreased with age of the seedlings. Susceptibility of the process to methyl jasmonate was confined to a narrow time interval where the developmentally regulated onset of alkaloid synthesis occurred. When methyl jasmonate was applied at later developmental stages, its ability to enhance alkaloid content in the seedlings declined sharply.
Cloning of cDNAs for genes that are specifically or preferentially expressed during the development of tobacco genetic tumors
Authors: Fujita Tomomichi , Kouchi Hiroshi , Ichikawa Takanari , Syõno Kunihiko 
Published: November 2004

SummaryTo identify genes involved in the formation of genetic tumors in interspecific hybrids (F1 between Nicotiana glauca and N. langsdorffii, genetic tumor‐related cDNA probes were obtained by a subtractive hybridization procedure and used to screen libraries of genetic tumor cDNAs. As a result, 17 distinct cDNA clones were isolated for genes that are specifically or preferentially expressed in genetic tumor tissues but are not expressed at all or are barely expressed in normal F1 plants. Among the isolated clones were genes that encoded so‐called stress proteins, such as glucan endo‐1,3‐β‐glucosidase, osmotin, pathogenesis‐related proteins and proteinase inhibitor I. Transcripts corresponding to two of the isolated cDNA clones accumulated to a significant extent only in genetic tumor tissues and were not present in callus tissues from parental plants or in the stems and leaves from normal F1 plants. Analysis of genomic DNA revealed that four of these clones hybridized only to genomic sequences from N. langsdorffii and one hybridized only to a genomic sequence from N. glauca. Eight apparently novel clones were further analyzed to determine the kinetics of accumulation of the corresponding mRNAs during development of genetic tumors. The patterns of accumulation of the mRNAs after induction of tumors by cutting of F1 stems could be divided into three groups, an indication that at least three distinct regulatory mechanisms are operative at the transcriptional level to control the expression of these tumor‐related genes during the formation of genetic tumors.
Control of transcription and mRNA turnover as mechanisms of metabolic repression of α‐amylase gene expression
Authors: Sheu Jun‐Jei , Jan Shr‐Peng , Lee Hung‐Tu , Yu Su‐May 
Published: November 2004

SummaryCarbon metabolites suppress the expression of α‐amylase genes in germinating seeds and in suspension‐cultured cells of rice. We have used suspension cell culture as a model system to study the mechanisms of metabolic regulation of α‐amylase gene expression in rice. Both transcription rate and mRNA stability increased as cells were starved of sucrose; the transcription rate of α‐amylase genes in cells starved of sucrose for 24 h was seven times greater than in cells provided with sucrose. The half‐life of α‐amylase mRNA was less than 1 h in cells provided with sucrose, but increased to 12 h in cells starved of this sugar. A protein synthesis inhibitor, cycloheximide (CHX), induced massive accumulation of a‐amylase mRNA in cells provided with sucrose. The longer half‐life of mRNA induced by sucrose starvation and the massive accumulation of mRNA caused by CHX were specific to the α‐amylase genes, since actin genes were not similarly affected. Our findings suggest that both transcriptional and post‐transcriptional control mechanisms are important in the metabolic regulation of α‐amylase gene expression and de novo synthesized proteins are involved in these mechanisms. The expression of α‐amylase and actin genes is regulated in an opposite manner by sugars, which also suggests the operation of a differential regulatory mechanism under different growth conditions.
Membrane potential‐dependent calcium transport in right‐side‐out plasma membrane vesicles from Zea mays L. roots
Authors: Marshall Jacqueline , Corzo Alfonso , Leigh Roger A. , Sanders Dale 
Published: November 2004

SummaryRight‐side‐out plasma membrane vesicles isolated from Zea mays roots were used to study membrane potential (ΔΨ)‐dependent Ca2+ transport. Membrane potentials were imposed on the vesicles using either K+ concentration gradients and valinomycin or SCN concentration gradients, and the size of the imposed ΔΨ was measured with [14C]tetraphenylphosphonium. Uptake of 45Ca2+ into the vesicles was stimulated by inside‐negative ΔΨ. The rate of transport increased to a maximum at a ΔΨ of about ‐80 mV and then declined at more negative ΔΨ. When extravesicular Ca2+ concentration was varied, uptake was maximal in the range 100–200 μM Ca2+. Neither dihydropyridine nor phenylalkylamine Ca2+ channel blockers had any effect on Ca2+ uptake but 30 μM ruthenium red was completely inhibitory with half maximal inhibition at 10–15 μM ruthenium red. Calcium transport was also inhibited by inorganic cations. Zn2+, Gd3+ and Mg2+ inhibited by a maximum of 30% while La3+, Nd3+ and Mn2+ inhibited by 70%. The inhibitory effects of La3+ and Gd3+ were additive. Lanthanum‐insensitive Ca2+ five Ca2+ transport was totally inhibited by 80 μM Gd3+ and showed maximum activity at a ΔΨ of ‐60 mV, with less uptake at both higher and lower ΔΨ. Lanthanum and Gd3+ also inhibited Ca2+ uptake into protoplasts isolated from Zea roots and their individual and combined effects were similar in extent to those observed with plasma membrane vesicles. It is concluded that maize root plasma membrane contains two Ca2+‐permeable channels that can be distinguished by their susceptibility to inhibition by La3+ and Gd3+. Both are inhibited by ruthenium red but not by other organic Ca2+ channel blockers.
In vivo aggregation of maize Activator (Ac) transposase in nuclei of maize endosperm and Petunia protoplasts
Authors: Heinlem Manfred , Brattig Torben , Kunze Reinhard 
Published: November 2004

SummaryThe transposase (TPase) of the maize transposon Activator (Ac) accumulates in the nuclei of maize endosperm and transfected Petunia protoplasts, where it aggregates into rod‐like structures about 2 μm in length. In petunia protoplasts the amount of TPase aggregates increases with the strength of the promoter fused to the Ac‐coding region. The excision frequency of a Ds element, however, does not increase proportionally. The data suggest that the aggregated TPase is not responsible for the mobilization of the Ds element, but rather is a transpositionally inactive form of the protein. In contrast to the full‐length TPase, a functional, N‐terminally truncated TPase derivative is inefficiently transported into the nucleus at high expression levels and aggregates predominantly in the cytoplasm. Accordingly, the N‐terminus of the TPase is involved in nuclear localization and/or aggregation.
Biologically induced systemic acquired resistance in Arabidopsis thaliana
Authors: Cameron Robin K. , Dixon Richard A. , Lamb Christopher J. 
Published: November 2004

SummaryLocal infection with a necrotizing pathogen can render plants resistant to subsequent infection by normally virulent pathogens. A system for biological induction of such systemic acquired resistance (SAR) in Arabidopsis thaliana is reported. When plants were immunized by local inoculation of a single leaf with avirulent Pseudomonas syringae pv. tomato (Pst) carrying the avrRpt2 avirulence gene, after 2 days other leaves became resistant, as measured symptomatically and by in planta bacterial growth, to challenge with a virulent Pst strain lacking this avirulence gene. Resistance was systemic and protected the plants against infection by other virulent pathogens including P. syringae pv. maculicola. Low‐dose inoculation induced a strong SAR and double immunizations did not increase the level of protection indicating that the response of only a few cells to the immunizing bacteria is required. SAR was not induced by the virulent strain of Pst lacking avrRpt2. However, experiments with the Arabidopsis RPS2 disease resistance gene mutant rps2‐201, which does not exhibit a local hypersensitive response to Pst carrying the corresponding avirulence gene avrRpt2, indicate that a hypersensitive response contributes to, but is not essential for, the induction of SAR. Thus, avrRpt2 activates either a branching signal pathway or separate parallel pathways for induction of localized hypersensitive resistance and SAR, with downstream potentiation of the systemic response by the local response. Using this system for the biological induction of SAR in Arabidopsis, it should be possible to dissect the molecular genetics of SAR by the isolation of mutants affected in the production, transmission, perception and transduction of the systemic signal(s).
Probabilistic approach in high‐cycle multiaxial fatigue: volume and surface effects
Authors: FLACELIERE L. , MOREL F. 
Published: November 2004

ABSTRACTThe stress gradient and the size of a component are known to influence the fatigue strength of metallic components. Indeed, in high‐cycle fatigue, experiments prove that the stress distribution as well as the size of the loaded specimen can be responsible for changes in the fatigue limit (for instance, the fatigue limits in tension and bending are different, and decrease with the size of the specimen). When dealing with multiaxial load conditions, those effects still act but a relevant criterion must be used to account for the complex state of stress. The weakest‐link concept together with a multiaxial endurance criterion based on a microplasticity analysis are then combined to describe the fatigue limit distribution of different metallic materials. Several load conditions are analysed: tension–compression, torsion, rotating bending and plane bending. By means of the proposed model, all the known effects on fatigue strength can be reflected. First, the endurance probability can be adequately predicted for any complex load conditions knowing some reference data from uniaxial fatigue tests. It can be linked to the probability of finding a defect with a critical size. The weakest‐link theory also accounts for the decrease of multiaxial fatigue limit with the stressed volume. For the same load condition (i.e. for the same stress distribution in the volume), the probability of finding a critical defect increases with the component size and then according to the weakest‐link theory the fatigue strength drops. A second model, based only on the damage developed at the surface, is also proposed. While the original Weibull theory makes no distinction between potential initiation sites at the free surface and in the volume and can lead to unsatisfactory predictions when applied to materials containing defects such as nodular cast iron, the new surface approach distinguishes between surface and volume effects.
The influence of aluminium alloy anisotropic texture on crack‐tip plasticity
Authors: POTIRNICHE G. P. , BARLAT F. , DANIEWICZ S. R. , GARRATT M. , BRAY G. 
Published: November 2004

ABSTRACTCrack‐tip plasticity in textured aluminium alloys was numerically analysed using an anisotropic yield function and an isotropic hardening law as the material constitutive response. Four real textures obtained from extrusions of rectangular and square shapes as well as five ideal textures typical of rolled products were considered and predicted crack‐tip plastic zones were compared with those obtained using the isotropic von Mises yield criterion. The use of the anisotropic yield function revealed important differences in crack‐tip plasticity compared with the isotropic case. The plastic zone features obtained for different textures were compared to single crystal results published in the open literature and similar crack‐tip plastic strain localization was observed.
Leadership for inclusion: a comparison of international practices
Authors: Kugelmass Judy , Ainscow Mel 
Published: November 2004

The issue of inclusion is high on the educational reform agenda in many countries. Set within the context of the United Nations organisation's push for ‘Education for All’, the aim is to find ways of increasing the participation and learning of pupils who are vulnerable to marginalisation within existing educational arrangements (World Education Forum, 2000). In the United States, inclusive education is generally thought of as an approach to serving children with disabilities within general education settings. Internationally, however, it is sometimes seen more broadly as a reform that supports and welcomes diversity among all learners (Ainscow, 1999). The research reported in this paper adopts this broadened formulation. It presumes that the aim of inclusive education is to eliminate social exclusion and that is a consequence of attitudes and responses to diversity in race, social class, ethnicity, religion, gender and ability (Vitello & Mithaug, 1998). Children with disabilities and others seen as having special educational needs are part of this agenda. The paper focuses specifically on the implications of these developments for leadership roles in schools. In particular, it uses evidence from case studies of leadership practice in three countries to address the question, what types of leadership practice foster inclusion in schools? The paper provides a theoretical framework that throws light on what is involved in such practices and presents illustrative examples. The aim is to provide an analysis that will be of direct relevance to practitioners, whilst at the same time adding to theory. The examples of leadership that are examined were found in schools in England, Portugal, and the United States that serve culturally and linguistically diverse groups of children, including significant numbers from low‐income families. In each of the schools, children with disabilities and others categorised as having special educational needs are taught in general education classrooms alongside their peers.
Reduced MPTP toxicity in noradrenaline transporter knockout mice
Authors: Rommelfanger Karen S. , Weinshenker David , Miller Gary W. 
Published: November 2004

AbstractThe noradrenergic neurons of the locus coeruleus (LC) are damaged in Parkinson's disease (PD). Neurotoxin ablation of the LC noradrenergic neurons has been shown to exacerbate the dopaminergic toxicity of MPTP, suggesting that the noradrenergic system protects dopamine neurons. We utilized mice that exhibit elevated synaptic noradrenaline (NA) by genetically deleting the noradrenaline transporter (NET), a key regulator of the noradrenergic system (NET KO mice). NET KO and wild‐type littermates were administered MPTP and striatal dopamine terminal integrity was assessed by HPLC of monoamines, immmunoblotting for dopaminergic markers and tyrosine hydroxylase (TH) immunohistochemistry. MPTP significantly reduced striatal dopamine in wild‐type mice, but not in the NET KO mice. To confirm that the protection observed in the NET KO mice was due to the lack of NET, we treated wild‐type mice with the specific NET inhibitor, nisoxetine, and then challenged them with MPTP. Nisoxetine conferred protection to the dopaminergic system. These data indicate that NA can modulate MPTP toxicity and suggest that manipulation of the noradrenergic system may have therapeutic value in PD.
Regulation of A2B adenosine receptor functioning by tumour necrosis factor a in human astroglial cells
Authors: Trincavelli Maria L. , Marroni Matteo , Tuscano Daniela , Ceruti Stefania , Mazzola Alessia , Mitro Nico , Abbracchio Maria P. , Martini Claudia 
Published: November 2004

AbstractLow‐affinity A2B adenosine receptors (A2B ARs), which are expressed in astrocytes, are mainly activated during brain hypoxia and ischaemia, when large amounts of adenosine are released. Cytokines, which are also produced at high levels under these conditions, may regulate receptor responsiveness. In the present study, we detected A2B AR in human astrocytoma cells (ADF) by both immunoblotting and real‐time PCR. Functional studies showed that the receptor stimulated adenylyl cyclase through Gs proteins. Moreover, A2B ARs were phosphorylated and desensitized following stimulation of the receptors with high agonist concentration. Tumour necrosis factor alpha (TNF‐α) treatment (24‐ h) increased A2B AR functional response and receptor G protein coupling, without any changes in receptor protein and mRNA levels. TNF‐α markedly reduced agonist‐dependent receptor phosphorylation on threonine residues and attenuated agonist‐mediated A2B ARs desensitization. In the presence of TNF‐α, A2B AR stimulation in vitro induced the elongation of astrocytic processes, a typical morphological hallmark of in vivo reactive astrogliosis. This event was completely prevented by the selective A2B AR antagonist MRS 1706 and required the presence of TNF‐α. These results suggest that, in ADF cells, TNF‐α selectively modulates A2B AR coupling to G proteins and receptor functional response, providing new insights to clarify the pathophysiological role of A2B AR in response to brain damage.
Minocycline prevents glutamate‐induced apoptosis of cerebellar granule neurons by differential regulation of p38 and Akt pathways
Authors: Pi Rongbiao , Li Wenming , Lee Nelson T. K. , Chan Hugh H. N. , Pu Yongmei , Chan Ling Nga , Sucher Nikolaus J. , Chang Donald C. , Li Mingtao , Han Yifan 
Published: November 2004

AbstractMinocycline has been shown to have remarkably neuroprotective qualities, but underlying mechanisms remain elusive. We reported here the robust neuroprotection by minocycline against glutamate‐induced apoptosis through regulations of p38 and Akt pathways. Pre‐treatment of cerebellar granule neurons (CGNs) with minocycline (10–100 µm) elicited a dose‐dependent reduction of glutamate excitotoxicity and blocked glutamate‐induced nuclear condensation and DNA fragmentations. Using patch‐clamping and fluorescence Ca2+ imaging techniques, it was found that minocycline neither blocked NMDA receptors, nor reduced glutamate‐caused rises in intracellular Ca2+. Instead, confirmed by immunoblots, minocycline in vivo and in vitro was shown to directly inhibit the activation of p38 caused by glutamate. A p38‐specific inhibitor, SB203580, also attenuated glutamate excitotoxicity. Furthermore, the neuroprotective effects of minocycline were blocked by phosphatidylinositol 3‐kinase (PI3‐K) inhibitors LY294002 and wortmannin, while pharmacologic inhibition of glycogen synthase kinase 3β (GSK3β) attenuated glutamate‐induced apoptosis. In addition, immunoblots revealed that minocycline reversed the suppression of phosphorylated Akt and GSK3β caused by glutamate, as were abolished by PI3‐K inhibitors. These results demonstrate that minocycline prevents glutamate‐induced apoptosis in CGNs by directly inhibiting p38 activity and maintaining the activation of PI3‐K/Akt pathway, which offers a novel modality as to how the drug exerts protective effects.
Ameliorating Pain in Nursing Homes: A Collaborative Quality‐Improvement Project
Authors: Baier Rosa R. , Gifford David R. , Patry Gail , Banks Sara M. , Rochon Therese , DeSilva Debra , Teno Joan M. 
Published: November 2004

Objectives: To evaluate a multifaceted intervention to improve pain‐management processes of care and outcomes in nursing homes.Design: Quasi‐experimental, pretest/posttest.Setting: Nursing homes in Rhode Island.Participants: Twenty‐one facilities.Intervention: This project used a multifaceted collaborative intervention involving audit and feedback of pain management, education, training, coaching using rapid‐cycle quality‐improvement techniques, and inter‐nursing home collaboration.Measurements: Pain‐management processes of care and outcomes, measured using chart review and the Minimum Data Set.Results: Of 21 facilities, 17 completed the project. Postintervention, nursing homes increased the use of appropriate pain assessments (3.9% vs 43.8%, P<.001), pain intensity scales (15.6% vs 73.9%, P<.001), and nonpharmacological treatments (40.5% vs 81.9%, P<.001). Prescriptions of World Health Organization Step II or Step III pain medications for residents with daily moderate or severe pain showed trends towards improvement (40.8% vs 50.6%, P=.057), but prescription of any pain medication (93.3% vs 94.6%, P=.710), change in pain medication (29.0% vs 30.1%, P=.386), and prescription of pain medications on a regularly scheduled basis (67.9% vs 69.5%, P=.370) did not. There was a 41.1% reduction in prevalence of pain (12.2% vs 7.2%, P=.032) between the pre‐ and postintervention time periods in the nursing homes that completed the project, whereas all the other facilities in Rhode Island (n=72) had only a 12.1% reduction (12.7% vs 11.2%, P=.286) during the same period.Conclusion: A multifaceted intervention improved pain‐management process and outcome measures in nursing homes.
The Concurrent Use of Anticholinergics and Cholinesterase Inhibitors: Rare Event or Common Practice?
Authors: Carnahan Ryan M. , Lund Brian C. , Perry Paul J. , Chrischilles Elizabeth A. 
Published: November 2004

Objectives: To measure the prevalence of anticholinergic use cross‐sectionally in patients receiving cholinesterase inhibitors and to describe change in use of anticholinergics upon inception of cholinesterase inhibitor treatment.Design: Cross‐sectional and inception cohort studies.Setting: State of Iowa.Participants: Iowa Medicaid beneficiaries aged 50 and older with a pharmacy claim for a cholinesterase inhibitor during January 1997 through February 2000.Measurements: Anticholinergic use was determined for all patients with a cholinesterase inhibitor pharmacy claim during January and February of 2000. A frequency distribution of all anticholinergics was compiled, with emphasis placed on those considered inappropriate in the elderly. In a separate analysis, anticholinergic use was determined at two points: 90 days before and after cholinesterase inhibitor inception.Results: Of 557 patients receiving a cholinesterase inhibitor, 197 (35.4%) received an anticholinergic concurrently. Of all anticholinergics, 74.5% (178/239) had been identified as inappropriate for use in the elderly, 22.2% (53/239) under any circumstances. At the time of cholinesterase inhibitor inception, 30.2% (143/474) and 33.5% (159/474) of patients received an anticholinergic 90 days before and 90 days after inception, respectively. Increases in anticholinergic prescribing upon cholinesterase inhibitor inception exceeded decreases (Wilcoxon signed‐rank test, S=529, P=.020).Conclusion: The concurrent use of anticholinergics and cholinesterase inhibitors is common although rarely appropriate. Patients with Alzheimer's disease deserve to receive the optimum benefit from cholinesterase inhibitor treatment, which can only be achieved through diligent and appropriate use of concurrent pharmacotherapy.