bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphogenetic modifications induced by Pseudomonas fluorescens A6RI and Glomus mosseae BEG12 in the root system of tomato differ according to plant growth conditions
Authors: Gamalero E. , Martinotti M. G. , Trotta A. , Lemanceau P. , Berta G. 
Published: March 2003

Summary

The ability of fluorescent pseudomonads and glomalean fungi to promote plant growth has been reported many times. However, little is known of their effects on root morphogenesis. Growth and root morphogenesis were compared in tomato ( Lycopersicon esculentum
) plants inoculated or not with a model strain of
Pseudomonas fluorescens
(A6RI) or with the arbuscular mycorrhizal fungus
Glomus mosseae (BEG12).
Plants were cultivated in a sandy‐loam soil mixed with sand at two different ratios (2 : 1 and 1 : 2), in gnotobiotic conditions. Plant growth was evaluated by measuring root and shoot fresh weight, and various morphometric parameters were compared.
Growth of control plants was less in the 1 : 2 than in the 2 : 1 soil : sand mixture, and root morphogenesis was also significantly altered by soil:sand mixture. P. fluorescens
A6RI promoted plant growth and increased total root length, surface area and volume in the more fertile soil:sand mixture (2 : 1) whereas
G. mosseae BEG12 did the same in the less fertile soil : sand mixture (1 : 2).
The relevance of differences between the two types of organisms in relation to the environmental conditions favourable for the expression of their beneficial effects is discussed in the context of microbial inoculation.
Poikilohydry and homoihydry: antithesis or spectrum of possibilities?
Authors: Proctor Michael C. F. , Tuba Zoltán 
Published: March 2003

SummaryPlants have followed two principal (and contrasting) strategies of adaptation to the irregular supply of water on land, which are closely bound up with scale. Vascular plants evolved internal transport from the soil to the leafy canopy (but their ‘homoihydry’ is far from absolute, and some are desiccation tolerant (DT)). Bryophytes depended on desiccation tolerance, suspending metabolism when water was not available; their cells are generally either fully turgid or desiccated. Desiccation tolerance requires preservation intact through drying–re‐wetting cycles of essential cell components and their functional relationships, and controlled cessation and restarting of metabolism. In many bryophytes and some vascular plants tolerance is essentially constitutive. In other vascular plants (particularly poikilochlorophyllous species) and some bryophytes tolerance is induced by water stress. Desiccation tolerance is adaptively optimal on hard substrates impenetrable to roots, and on poor dry soils in seasonally dry climates. DT vascular plants are commonest in warm semiarid climates; DT mosses and lichens occur from tropical to polar regions. DT plants vary widely in their inertia to changing water content. Some mosses and lichens dry out and recover within an hour or less; vascular species typically respond on a time scale of one to a few days.

Contents

Summary
327

I.
Introduction
328

II.
The soil–plant–atmosphere continuum
329

III.
Desiccation‐tolerant plants: taxonomic distribution and functional characteristics
331

IV.
Anatomical and physiological requirements and implications of desiccation tolerance
333

V.
Time‐scale considerations and ecological adaptation
340

VI.
Conclusion
344

Acknowledgements
344

References
344
Phosphorus acquisition and use: critical adaptations by plants for securing a nonrenewable resource
Authors: Vance Carroll P. , Uhde‐Stone Claudia , Allan Deborah L. 
Published: March 2003

SummaryPhosphorus (P) is limiting for crop yield on > 30% of the world's arable land and, by some estimates, world resources of inexpensive P may be depleted by 2050. Improvement of P acquisition and use by plants is critical for economic, humanitarian and environmental reasons. Plants have evolved a diverse array of strategies to obtain adequate P under limiting conditions, including modifications to root architecture, carbon metabolism and membrane structure, exudation of low molecular weight organic acids, protons and enzymes, and enhanced expression of the numerous genes involved in low‐P adaptation. These adaptations may be less pronounced in mycorrhizal‐associated plants. The formation of cluster roots under P‐stress by the nonmycorrhizal species white lupin (Lupinus albus), and the accompanying biochemical changes exemplify many of the plant adaptations that enhance P acquisition and use. Physiological, biochemical, and molecular studies of white lupin and other species response to P‐deficiency have identified targets that may be useful for plant improvement. Genomic approaches involving identification of expressed sequence tags (ESTs) found under low‐P stress may also yield target sites for plant improvement. Interdisciplinary studies uniting plant breeding, biochemistry, soil science, and genetics under the large umbrella of genomics are prerequisite for rapid progress in improving nutrient acquisition and use in plants.

Contents

I.
Introduction
424

II.
The phosphorus conundrum
424

III.
Adaptations to low P
424

IV.
Uptake of P
424

V.
P deficiency alters root development and function
426

VI.
P deficiency modifies carbon metabolism
431

VII.
Acid phosphatase
436

VIII.
Genetic regulation of P responsive genes
437

IX.
Improving P acquisition
439

X.
Synopsis
440
Factors involved in the learning of consumer studies
Authors: Byrne Mike S. 
Published: March 2003

AbstractThis study explored links between students’ psychological traits and their expressed preferences for learning approaches, and performance, on a consumer studies degree course. Measures to assess field independence, convergence–divergence and Perry position (a developmental classification based on students’ attitudes to knowledge and learning), and students’ preferences with regard to directed, group, project and practical learning approaches, were administered to 60 final‐year and 56 first‐year students on a consumer studies degree course. Perry position and a preference for a project learning approach were found to correlate most highly with overall performance. Field independence and convergence–divergence did not correlate at statistically significant levels with any element of final degree performance. As students proceeded through the course, they developed an enhanced view of a project learning approach and a diminished view of a group learning approach. On the basis of these findings, a number of recommendations for the teaching and learning consumer studies are put forward.
Children as consumers – snacking behaviour in primary school children
Authors: Bower John A. , Sandall Louise 
Published: March 2003

AbstractEighty‐four primary school children (the majority aged 7–8 years), from four schools, two in England and two in Scotland, were surveyed to identify snacking behaviour and the influences on perception and choice of snack foods. A questionnaire plus short interview with activity tasks was adopted, covering general snacking habits and a look at six specific groups of snacks comprising three of ‘unhealthy’ image and three with intermediate or fully ‘healthy’ image. The results showed that, for this age group, there was an overall preference for sweets, crisps and chocolate and less liking for fruit and cereal‐containing snacks. Attitudes to sensory properties showed that ‘taste’ was the main reason for snack choices, usually in spite of a ‘healthy’ image belief for the snacks. Choice was also dependent on parental influence and availability. Gender and relative socio‐economic level differences were minimal, but regional variations showed higher snacking frequency for the Scottish group, which also had fewer children preferring fruit. Meal patterns had little effect on snacking, but inclusion of a prepared meal at lunchtime may have reduced snacking frequency.
Evidence‐based librarianship: what might we expect in the years ahead?*
Authors: Eldredge Jonathan D. 
Published: March 2003

AbstractObjective: To predict the possible accomplishments of the Evidence‐Based Librarianship (EBL) movement by the years 2005, 2010, 2015 and 2020.Methods: Predictive. The author draws upon recent events, relevant historical events and anecdotal accounts to detect evidence of predictable trends.Results: The author develops a set of probable predictions for the development of EBL. Although incomplete evidence exists, some trends still seem discernible.Conclusion: By 2020, EBL will have become indistinguishable from mainstream health sciences librarianship/informatics practices.
Surfing for health: user evaluation of a health information website. Part one: background and literature review
Authors: Williams Peter , Nicholas David , Huntington Paul , McLean Fiona 
Published: March 2003

AbstractThe Government in Britain is set on using the Internet to expand the provision of health information to the general public. Concerns over the quality of the health information have preoccupied commentators and organizations rather than the way users interact with health information systems. This report examines the issues surrounding the provision of electronic health information, and describes an evaluation undertaken of a commercial health website—that of Surgerydoor (http://www.surgerydoor.co.uk/), and comprises two parts. Part one outlines the literature on electronic health information evaluation. It discusses quality issues, but also redresses the imbalance by exploring other evaluative perspectives. Part two describes an evaluation of a health information Internet site in terms of its usability and appeal, undertaken as part of a Department of Health funded study on the impact of such systems.
The US National Library of Medicine in the 21st century: expanding collections, nontraditional formats, new audiences
Authors: Lacroix Eve‐Marie , Mehnert Robert 
Published: March 2003

AbstractFrom the early 1960s, the US National Library of Medicine (NLM) has been a leader in applying computer technology to accomplish traditional bibliographic and reference functions. medline, in the early 1970s, was the first large‐scale online medical bibliographic reference system. That role has been altered by today's Web environment, which has increased the number and extent of NLM services and the audience for them. The NLM has formally declared that it will seek to serve the general public after over a century of serving the library and medical communities exclusively. In the last several years, many new services have been introduced to fulfil this mandate, including medlineplus and ClinicalTrials.gov. Also a part of the NLM's vision for the 21st century is the need to ensure that the proliferating forms of electronic health information—bibliographic, full text, graphic, audiovisual—are captured and preserved for posterity. A national library such as the NLM has as much an archival responsibility for this electronic information as for centuries‐old printed and manuscript historical treasures.
Protein kinase C delta regulates neural cell adhesion molecule polysialylation state in the rat brain
Authors: Gallagher Helen C. , Murphy Keith J. , Foley Andrew G. , Regan Ciaran M. 
Published: March 2003

Polysialylation of neural cell adhesion molecule (NCAM PSA) modulates cell–cell homophilic binding and signalling during brain development and the remodelling of discrete brain regions in the adult. Following learning, a transient increase in the frequency of polysialylated neurones occurs in the dentate gyrus of the hippocampal formation, and this has been correlated with the selective retention and/or elimination of synapses that are transiently overproduced during memory consolidation. We now demonstrate that protein kinase C delta (PKCδ) negatively regulates polysialyltransferase activity in the rat brain during development and also in the hippocampus during memory consolidation, where its down‐regulation in the Golgi membrane fraction coincides with the transient increase in NCAM PSA expression. Decreased expression of PKCδ was also observed in the hippocampus of rats reared in a complex environment and this directly contrasted the significant increase in frequency of hippocampal polysialylated neurones observed in these animals. These effects were isoform‐specific as no change in total PKC enzyme activity was detected during memory consolidation and complex environment rearing had no effect on the hippocampal expression of PKCα, β, γ or ε. By sequential immunoprecipitation and immunoblot analysis, phosphorylation of polysialyltransferase protein(s) was (were) demonstrated to occur on both serine and tyrosine residues and this was associated with decreased enzyme activity. Moreover, a similar experimental approach revealed the degree of PKCδ co‐precipitation with polysialyltransferase protein(s) to be inversely correlated with polysialyltransferase activity. These findings support in vitro evidence indicating PKCδ to regulate polysialyltransferase activity and NCAM polysialylation state.
Nerve growth factor modulates the expression and secretion of β‐amyloid precursor protein through different mechanisms in PC12 cells
Authors: Villa Ana , Latasa Maria Jesús , Pascual Angel 
Published: March 2003

The β‐amyloid protein, component of the senile plaques found in Alzheimer brains is proteolytically derived from the β‐amyloid precursor protein (APP), a larger membrane‐associated protein that is expressed in both neural and non‐neural cells. Overexpression of APP might be one of the mechanisms that more directly contributes to the development of Alzheimer's disease. The APP gene expression is regulated by a number of cellular mediators including nerve growth factor (NGF) and other ligands of tyrosine kinase receptors. We have previously described that NGF increases APP mRNA levels in PC12 cells. However, the molecular mechanisms and the precise signalling pathways that mediate its regulation are not yet well understood. In the present study we present evidence that NGF, and to a lesser extent fibroblast growth factor and epidermal growth factor, stimulate APP promoter activity in PC12 cells. This induction is mediated by DNA sequences located between the nucleotides − 307 and − 15, and involves activation of the Ras–MAP kinase signalling pathway. In contrast, we have also found that NGF‐induced secretion of soluble fragments of APP into the culture medium is mediated by a Ras independent mechanism.
Nigrostriatal denervation does not affect glutamate transporter mRNA expression but subsequent levodopa treatment selectively increases GLT1 mRNA and protein expression in the rat striatum
Authors: Liévens J.‐C. , Salin P. , Nieoullon A. , Kerkerian‐Le Goff L. 
Published: March 2003

There is growing evidence that the loss of the nigrostriatal dopaminergic neurones induces an overactivity of the corticostriatal glutamatergic pathway which seems to be central to the physiopathology of parkinsonism. Moreover, glutamatergic mechanisms involving NMDA receptors have been shown to interfere with the therapeutical action of levodopa. Given the key role played by uptake processes in glutamate neurotransmission, this study examined the effects of nigrostriatal deafferentation and of levodopa treatment on the striatal expression of the glutamate transporters GLT1, GLAST and EAAC1 in the rat. No significant changes in striatal mRNA levels of these transporters were detected after either levodopa treatment (100 mg/kg; i.p., twice a day for 21 days) or unilateral lesion of the nigrostriatal pathway by intranigral 6‐hydroxydopamine injection. In contrast, animals with the lesion subsequently treated with levodopa showed a selective increase (36%) in GLT1 mRNA levels in the denervated striatum versus controls. These animals also showed increased GLT1 protein expression, as assessed by immunostaining and western blotting. These data provide the first evidence that levodopa therapy may interfere with striatal glutamate transmission through change in expression of the primarily glial glutamate transporter GLT1. We further suggest that levodopa‐induced GLT1 overexpression may represent a compensatory mechanism preventing neurotoxic accumulation of endogenous glutamate.
Norepinephrine triggers Ca2+‐dependent exocytosis of 5‐hydroxytryptamine from rat pinealocytes in culture
Authors: Yamada Hiroshi , Hayashi Mitsuko , Uehara Shunsuke , Kinoshita Mika , Muroyama Akiko , Watanabe Masami , Takei Koji , Moriyama Yoshinori 
Published: March 2003

Abstract5‐Hydroxytryptamine (5‐HT) is a precursor and a putative modulator for melatonin synthesis in mammalian pinealocytes. 5‐HT is present in organelles distinct from l‐glutamate‐containing synaptic‐like microvesicles as well as in the cytoplasm of pinealocytes, and is secreted upon stimulation by norepinephrine (NE) to enhance serotonin N‐acetyltransferase activity via the 5‐HT2 receptor. However, the mechanism underlying the secretion of 5‐HT from pinealocytes is unknown. In this study, we show that NE‐evoked release of 5‐HT is largely dependent on Ca2+ in rat pinealocytes in culture. Omission of Ca2+ from the medium and incubation of pineal cells with EGTA‐tetraacetoxymethyl‐ester inhibited by 59 and 97% the NE‐evoked 5‐HT release, respectively. Phenylephrine also triggered the Ca2+‐dependent release of 5‐HT, which was blocked by phentolamine, an α antagonist, but not by propranolol, a β antagonist. Botulinum neurotoxin type E cleaved 25 kDa synaptosomal‐associated protein and inhibited by 50% of the NE‐evoked 5‐HT release. Bafilomycin A1, an inhibitor of vacuolar H+‐ATPase, and reserpine and tetrabenazine, inhibitors of vesicular monoamine transporter, all decreased the storage of vesicular 5‐HT followed by inhibition of the NE‐evoked 5‐HT release. Agents that trigger l‐glutamte exocytosis such as acetylcholine did not trigger any Ca2+‐dependent 5‐HT release. Vice versa neither NE nor phenylephrine caused synaptic‐like microvesicle‐mediated l‐glutamate exocytosis. These results indicated that upon stimulation of a adrenoceptors pinealocytes secrete 5‐HT through a Ca2+‐dependent exocytotic mechanism, which is distinct from the exocytosis of synaptic‐like microvesicles.
Expression of Cdk5 and its activators in NT2 cells during neuronal differentiation
Authors: Fu Wing‐Yu , Wang Jerry H. , Ip Nancy Y. 
Published: March 2003

AbstractWe have recently developed a rapid protocol involving NT2 cell aggregation and treatment with retinoic acid (RA) to produce terminally differentiated CNS neurons. As a first step to explore the functional roles of cell‐cycle regulatory proteins in the process of neuronal differentiation, the expression profiles of cyclin‐dependent kinases (Cdks) and their regulators were examined in NT2 cells following treatment with RA. One of the Cdks, Cdk5, has been demonstrated to affect the process of neuronal differentiation and suggested to play an important role in development of the nervous system. We found that the expression of Cdk5 was gradually increased, while its activators (p35 and p39) as well as Cdk5 kinase activity were induced in NT2 cells during the process of neuronal differentiation. Moreover, both p35 and p39 were localized along the axons and varicosity‐like structures of differentiated NT2 neurons. Taken together, our results demonstrated that NT2 cells provide a good in vitro model system to examine signaling pathways involved in the regulation of Cdk5 activators and to elucidate the functional roles of Cdk5 in neuronal differentiation.
Profound molecular changes following hippocampal slice preparation: loss of AMPA receptor subunits and uncoupled mRNA/protein expression
Authors: Taubenfeld Stephen M. , Stevens Kimberly A. , Pollonini Gabriella , Ruggiero Jason , Alberini Cristina M. 
Published: March 2003

AbstractThe acute hippocampal slice preparation is a convenient, in vitro model widely used to study the biological basis of synaptic plasticity. Although slices may preserve their electrophysiological properties for several hours, profound molecular changes in response to the injury caused by the slicing procedure are likely to occur. To determine the magnitude and duration of these changes we examined the post‐slicing expression kinetics of three classes of genes known to be implicated in long‐term synaptic plasticity: glutamate AMPA receptors (GluR), transcription factors and neurotrophins. Slicing resulted in a striking loss of GluR1 and GluR3, but not of GluR2 proteins suggesting that rapid changes in the composition of major neurotransmitter receptors may occur. Slicing caused a significant induction of the transcription factors c‐fos, zif268, CCAAT enhancer binding protein (C/EBP) β and δ mRNAs and of the neurotrophin brain‐derived neurothophic factor (BDNF) mRNA. In contrast, there was no augmentation, and sometimes a decline, in the levels of the corresponding proteins. These data reveal that significant discrepancies exist between the slice preparation and the intact hippocampus in terms of the metabolism of molecular components known to be involved in synaptic plasticity.
Intracellular distribution of the fluorescent dye nonyl acridine orange responds to the mitochondrial membrane potential: implications for assays of cardiolipin and mitochondrial mass
Authors: Jacobson Jake , Duchen Michael R. , Heales Simon J. R. 
Published: March 2003

AbstractCardiolipin, a polyunsaturated acidic phospholipid, is found exclusively in bacterial and mitochondrial membranes where it is intimately associated with the enzyme complexes of the respiratory chain. Cardiolipin structure and concentration are central to the function of these enzyme complexes and damage to the phospholipid may have consequences for mitochondrial function. The fluorescent dye, 10 nonyl acridine orange (NAO), has been shown to bind cardiolipin in vitro and is frequently used as a stain in living cells to assay cardiolipin content. Additionally, NAO staining has been used to measure the mitochondrial content of cells as dye binding to mitochondria is reportedly independent of the membrane potential. We used confocal microscopy to examine the properties of NAO in cortical astrocytes, neonatal cardiomyocytes and in isolated brain mitochondria. We show that NAO, a lipophilic cation, stained mitochondria selectively. However, the accumulation of the dye was clearly dependent upon the mitochondrial membrane potential and depolarisation of mitochondria induced a redistribution of dye. Moreover, depolarisation of mitochondria prior to NAO staining also resulted in a reduced NAO signal. These observations demonstrate that loading and retention of NAO is dependant upon membrane potential, and that the dye cannot be used as an assay of either cardiolipin or mitochondrial mass in living cells.