bluuebunny/crossref_metadata_2025 huggingface dataset:
Induced defence responses limit Hartig net formation in ectomycorrhizal birch roots
Authors: FEUGEY L. , STRULLU D.‐G. , POUPARD P. , SIMONEAU P.
Published: March 2003

Roots of clonal birches (Betula pendula) were inoculated with the ectomycorrhizal fungi Paxillus involutus (isolates P0 and Mi) and Hebeloma cylindrosporum (strains D1 and D105). These fungi showed different rates of mycorrhiza formation in vitro. Mature mycorrhizas were obtained after only 2–4 d with H. cylindrosporum, whereas 6–8 d were necessary with P. involutus isolate P0, and P. involutus isolate Mi was not able to form mature mycorrhiza during the 10 d of the experiment. Temporal changes in PAL activity and the expression of genes encoding intracellular pathogenesis‐related proteins were followed after inoculating birch roots with these fungi. Transient increase of PAL activity, and transient induction of expression of the wound‐inducible Bet v1‐SC1 gene, were observed in roots challenged with both H. cylindrosporum strains and the P. involutus isolate P0. These changes were found to coincide with hyphal penetration between root cells during Hartig net formation, and were never observed in roots inoculated with the poorly aggressive P. involutus isolate Mi. Examination of mycorrhizal root sections under u.v. light indicated the presence of phenolic compounds in the host cell walls at the vicinity of the Hartig net. These results strongly suggest that hyphal penetration between the root cells triggers a transient defence response which, in turn, could limit Hartig net formation to the outer layer of the root cortex.
Identification and characterization of a new group of root‐colonizing fungi within the Gaeumannomyces–Phialophora complex
Authors: ULRICH KRISTINA , AUGUSTIN CLAUDIA , WERNER ARMIN
Published: March 2003

A new group of darkly pigmented root‐infecting fungi was isolated from cereal roots obtained from six different locations in northeastern Germany. Similar random amplified polymorphic DNA(RAPD) patterns and restriction profiles of amplified rDNA were used as a basis for classifying the isolates in a separate group. The isolates demonstrating mycelial and infection characteristics typical of Gaeumannomyces graminis could be differentiated from the varieties of G. graminis as well as from Gaeumannomyces cylindrosporus/Phialophora graminicola using RAPD Polymerase chain reaction (PCR) and rDNA Restriction‐fragment length polymorphism (RFLP) analysis. Phylogenetic analysis of the Internal transcribed spacer (ITS) regions suggests that the isolates form a distinct group (named group ‘E’) situated within the Gaeumannomyces–Phialophora complex between the branch of the G. graminis varieties and Gaeumannomyces incrustans/Magnaporthe poae. Isolates of group E produced lobed hyphopodia and were shown in biotests to be non‐pathogenic to wheat, oats, Italian Ryegrass and Chewings Fescue, suggesting it is a benign parasite which colonizes cereals or grasses without destroying vascular tissue. Furthermore, curved phialospores could be found. Summarizing the results presented, this new group could be classified as a new species of Phialophora. Although isolates of group E were found at only six of the 32 investigated locations, they composed up to 50% of total isolates of the Gaeumannomyces–Phialophora complex at these sites. Because of the non‐pathogenic behaviour, the new group may be of value as biological control agents for pathogenic fungi.
Tansley Review No. 110.
Authors: ARDITTI JOSEPH , GHANI ABDUL KARIM ABDUL
Published: March 2003

Orchid seeds are very small, extremely light and produced in great numbers. Most range in length from c. 0.05 to 6.0 mm, with the difference between the longest and shortest known seeds in the family being 120‐fold. The ‘widest’ seed at 0.9 mm is 90‐fold wider than the ‘thinnest’ one, which measures 0.01 mm (because orchid seeds are tubular or balloon‐like, ‘wide’ and ‘thin’ actually refer to diameter). Known seed weights extend from 0.31 lg to 24 μg (a 78‐fold difference). Recorded numbers of seeds per fruit are as high as 4000000 and as low as 20–50 (80000–200000‐fold difference). Testae are usually transparent, with outer cell walls that may be smooth or reticulated. Ultrasonic treatments enhance germination, which suggests that the testae can be restrictive. Embryos are even smaller: their volume is substantially smaller than that of the testa. As a result, orchid seeds have large internal air spaces that render them balloon‐like. They can float in the air for long periods, a property that facilitates long‐distance dispersal. The difficult‐to‐wet outer surfaces of the testa and large internal air spaces enable the seeds to float on water for prolonged periods. This facilitates distribution through tree effluates and/or small run‐off rivulets that may follow rains. Due to their size and characteristics, orchid seeds may also be transported in and on land animals and birds (in fur, feathers or hair, mud on feet, and perhaps also following ingestion).

contents

Summary
367

I.
Introduction
367

II.
Number
368

III.
Size
379

IV.
Air space in the seeds
381

V.
Floatation and dispersal
383

VI.
Conclusions
417

Acknowledgements
417

References
418
Temporal synthesis and radiolabelling of the sorghum 3‐deoxyanthocyanidin phytoalexins and the anthocyanin, cyanidin 3‐dimalonyl glucoside
Authors: WHARTON PHILLIP S. , NICHOLSON RALPH L.
Published: March 2003

Sorghum (Sorghum bicolor) synthesizes a complex mixture of 3‐deoxyanthocyanidin phytoalexins in response to
inoculation with the non‐pathogenic fungus Bipolaris maydis. The anthocyanin cyanidin 3‐dimalonyl glucoside,
is also synthesized naturally in response to light. To determine the order and time of appearance of these
compounds, etiolated sorghum mesocotyls were inoculated with B. maydis and tissue extracts were analysed by
photodiode array‐HPLC every 2 h for the first 24 h and at 48 h post inoculation (hpi). Uninoculated and inoculated
etiolated mesocotyls were also allowed to incorporate L‐[U‐14C] phenylalanine. Apigeninidin appeared at 10 hpi,
followed by luteolinidin and apigeninidin 5‐O‐arabinoside at 14 hpi. Luteolinidin 5‐methylether was not detected
until 18 hpi and apigeninidin 7‐methylether not until 20 hpi. The concentrations of the primary phytoalexins,
apigeninidin, luteolinidin and apigeninidin 5‐O‐arabinoside, rose steadily between 12 and 24 hpi, and the levels
of apigeninidin and luteolinidin were approximately equivalent by 24 hpi. However, between 24 and 48 hpi
luteolinidin and luteolinidin 5‐methylether accumulated rapidly so that by 48 hpi the amounts of luteolinidin and
luteolinidin 5‐methylether had increased approximately twofold. Radiolabelling also showed that 14C was incorporated into the 3‐deoxyanthocyanidins and cyanidin 3‐dimalonyl glucoside. Several other unidentified phenolic compounds also accumulated radioactivity.
Links between genetic and functional diversity – a bridge too far?
Authors: Read David
Published: March 2003

The view that nutrient acquisition by most plants growing in natural ecosystems is mediated by mycorrhiza‐forming symbiotic fungi is now largely accepted. With this perception comes the need to learn more about the identity of the organisms responsible for these key processes. Herein lies a challenge taken up by Vrålstad et al. on pp. 549–563 in this issue.
Differences in glucosinolate patterns and arbuscular mycorrhizal status of glucosinolate‐containing plant species
Authors: VIERHEILIG H. , BENNETT R. , KIDDLE G. , KALDORF M. , LUDWIG‐MÜLLER J.
Published: March 2003

Under defined laboratory conditions it was shown that two glucosinolate‐containing plant species, Tropaeolum
majus and Carica papaya, were colonized by arbuscular mycorrhizal (AM) fungi, whereas it was not possible to
detect AM fungal structures in other glucosinolate‐containing plants (including several Brassicaceae).
Benzylglucosinolate was present in all of the T. majus cultivars and in C. papaya it was the major glucosinolate.
2‐Phenylethylglucosinolate was found in most of the non‐host plants tested. Its absence in the AM host plants
indicates a possible role for the isothiocyanate produced from its myrosinase‐catalysed hydrolysis as a general AM
inhibitory factor in non‐host plants. The results suggest that some of the indole glucosinolates might also be
involved in preventing AM formation in some of the species. In all plants tested, both AM hosts and non‐hosts,
the glucosinolate pattern was altered after inoculation with one of three different AM fungi (Glomus mosseae,
Glomus intraradices and Gigaspora rosea), indicating signals between AM fungi and plants even before root
colonization. The glucosinolate induction was not specifically dependent on the AM fungus. A time‐course study
in T. majus showed that glucosinolate induction was present during all stages of mycorrhizal colonization.
Saprotrophic invasion by the soil‐borne fungal plant pathogen Rhizoctonia solani and percolation thresholds
Authors: BAILEY D. J. , OTTEN W. , GILLIGAN C. A.
Published: March 2003

In this paper we distinguish between invasive and noninvasive (finite) saprotrophic spread of the soil‐borne fungal plant pathogen, Rhizoctonia solani amongst discrete sites of nutrient resource. Using simple concepts of
percolation theory, we predict the critical threshold distance, associated with a threshold probability, between
donor (colonized) and recipient (uncolonized) nutrient sites at which R. solani can spread invasively by mycelial growth through a population of nutrient sites on a lattice. The critical distance for invasive spread is estimated from colonization profiles derived from placement experiments that summarize the probability of colonization with distance between replicated pairs of colonized and uncolonized sites. Colonization profiles were highly nonlinear, decaying sigmoidally with distance. Thresholds for invasive spread were predicted at inter‐site distances of 8.1 mm and 11.8 mm for sites of low and high nutrient agar, respectively. In population experiments with inter‐site distances below the predicted thresholds, the spread of the fungus was invasive in all replicates. At large distances (>10 mm for low, and >14 mm for high nutrient sites) the spread of the fungus was always finite, with the proportion of finite replicates decreasing sharply close to the percolation threshold. Invasive spread did not depend on the furthest extent of growth of the fungus but on distances predicted by the percolation thresholds. Invasive spread of the fungus is also examined in a more natural and variable, nonsterile system involving the growth and colonization of a lattice of poppy seeds over sand. The system is characterized by a decay in the probability of colonization between older poppy seeds, which effectively ‘quenches’ saprotrophic spread. Hence in the population experiments with poppy seeds all growth was ultimately finite. The threshold distance, corresponding to the critical percolation probability for invasive growth changed from 18 mm to 4 mm over 21d leading to a switch from invasive to finite growth. We conclude that percolation theory can be used to link the growth of individual mycelial colonies to the formation of patches that result from the colonization of particulate organic matter. The nonlinearity of the colonization profiles combined with the presence of a percolation threshold means that small changes in the distance between nutrient sites can result in large differences in final patch size. The rapid decay of particulate organic matter in a more natural system can have a profound effect on the dynamics of colonization, restricting saprotrophic invasion of the soil. The consequences of invasion thresholds for colony growth of saprotrophic and parasitic fungi in dynamical systems are briefly discussed.
Editorial
Authors: Norby Richard , Fitter Alastair , Jackson Robert
Published: March 2003

This Special Issue of New Phytologist contains the latest information and new ideas about how root dynamics
might alter in the face of a globally changing environment. The importance of this topic is clear: changes
in the production and turnover of roots in forests and grasslands in response to rising atmospheric CO2 concentrations, elevated temperatures, altered precipitation, or nitrogen deposition could be a key link between plant responses and longer‐term changes in soil organic matter and ecosystem carbon balance.

The introductory review (Norby & Jackson, 2000), which draws together the different contributions to the volume, asks three central questions:

• Do elevated atmospheric CO2, nitrogen deposition, and climatic change alter the dynamics of root production and mortality?

• How do physiological responses of roots to global change factors impact whole‐plant and ecosystem metabolism?

• What are the implications of root dynamics for soil microbial communities and the fate of carbon in soil?

Ecosystem‐level observations of root production and mortality in response to global change factors are just starting to emerge. The challenge to root biologists is to overcome the profound methodological and analytical problems and assemble a more comprehensive data set from which ecosystem responses can be explained. The commissioned reviews and research papers in this volume attempt to meet that challenge. Following the introductory review, three papers provide a framework for subsequent analyses by presenting a global perspective on root turnover, a review of morphological and physiological attributes of roots, and a discussion of concepts of carbon allocation in plants. This is followed by a series of papers describing experimental studies on the effects of elevated CO2 and climatic change in various ecosystems. Three papers consider the physiological responses of roots to global change factors, followed by three papers reviewing mycorrhizal interactions and soil biology, and the implications for carbon sequestration in soil. The final paper returns to a global perspective with an analysis of how roots are handled in models of global change. Throughout these articles there is information on topics such as methodology for studying root dynamics, the major gaps in our knowledge, and the idea that leaves are a good analogy for roots.
Transmembrane electric potential difference of germ tubes of arbuscular mycorrhizal fungi responds to external stimuli
Authors: AYLING S. M. , SMITH S. E. , SMITH F. A.
Published: March 2003

Measurements of the electric potential difference across the hyphal wall and the cell membrane were made on external hyphae of three species of arbuscular mycorrhizal fungus Gigaspora margarita, Scutellospora calospora and
Glomus coronatum and on germ tubes of Gi. margarita. The values of transmembrane electric potential difference
recorded (∼–40 mV) are less negative than those previously reported from hyphae of arbuscular mycorrhizal
fungi closely associated with roots and from filamentous fungi. The external hyphae of arbuscular mycorrhizal
fungi grown in soil had similar values of electric potential difference to those grown in soil‐less culture, and to germ
tubes. Thermodynamic calculations showed that despite these low values of electric potential difference, efficient
high‐affinity uptake of phosphate is possible. The transmembrane electric potential difference of germ tubes of Gi.
margarita became more negative when plant root extract was added to the medium, showing for the first time that
the early stages of interaction between plant and fungus occur via direct effects on the plasma membrane rather
than via effects on gene expression. Addition of K+
reversibly depolarized the transmembrane electric potential
difference of germ tubes of Gi. margarita, indicating that despite the low electric potential difference the fungus
has control over the permeability of the plasmamembrane to K+.
Morph‐specific patterns of variation in stigma height in natural populations of distylous Jasminum fruticans
Authors: THOMPSON JOHN D. , DOMMÉE BERTRAND
Published: March 2003

The purpose of this study was to describe morph‐specific patterns of stigma–anther separation and style curling in the distylous Jasminum fruticans. We also examined whether variation in floral traits is correlated with variation in seed production. Stigma–anther separation is more variable in short‐styled plants than in long‐styled plants. In all populations studied, some plants bear flowers that lack any stigma–anther separation. These plants have the pollen characteristics (size and number) and compatibility relations of short‐styled plants. Comparison with other distylous species illustrates that the variability of stigma–anther separation in short‐styled plants is a novel finding for a distylous species. Long‐styled plants have greater stigma–anther separation than short‐styled plants, styles are often curled and protrude from the corolla, and anthers are placed well within the corolla tube. The frequency of long‐styled plants with curled styles and the mean degree of style curling were significantly correlated with style length. Short‐styled plants have larger corollas than long‐styled plants and never have curled styles. Morph ratios are always 50∶50 in natural populations. Mean values of each floral trait in the two morphs were significantly correlated among populations. There were no consistent differences in fecundity of the two morphs nor any correlation between floral traits and seed set for each morph in natural populations. We discuss the potential causes and significance of the two morph‐specific patterns we describe; reduced stigma–anther separation in short‐styled plants and the presence of curled styles in long‐styled plants.
A breakthrough for wood decay fungi
Authors: Eaton Rodney
Published: March 2003

For wood mycologists, the work of Savory (1954a,b) marked an important step in the understanding of decay processes by lignolytic fungi. His description of decay by ascomycete and deuteromycete fungi in wood from industrial water cooling towers revealed a particular pattern observed previously by Bailey & Vestal (1937), Tamblyn (1937) and Barghoorn & Linder (1944) in wood from other situations. This type of decay was termed ‘soft rot’ because of the spongy texture of the wood surface. Soft rot, characterized by hyphal penetration of the wood cell walls in a fashion similar to sap‐stain fungi, results in the formation of decay cavities in the central zone of wood cell walls, which leads to their ultimate destruction. Soft rot was therefore described as distinct from the brown and white rot forms of wood decay normally attributed to lignolytic basidiomycetes and some of the larger ascomycetes, such as members of the Xylariaceae. Indeed, members of the genera Daldinia, Hypoxylon and Xylaria have usually been considered to be white rot fungi. However, the boundaries between these three types of fungal decay have since become less clear‐cut and a report in this issue, of a study into hyphal penetration of the reaction zone in beechwood (Schwarze and Baum, pp. 129–140), identifies different penetration mechanisms.
The apoplast and its significance for plant mineral nutrition
Authors: Sattelmacher Burkhard
Published: March 2003

It has only recently become apparent that the apoplast plays a major role in a diverse range of processes, including intercellular signalling, plant–microbe interactions and both water and nutrient transport. Broadly defined, the apoplast constitutes all compartments beyond the plasmalemma – the interfibrillar and intermicellar space of the cell walls, and the xylem, including its gas‐ and water‐filled intercellular space – extending to the rhizoplane and cuticle of the outer plant surface. The physico‐chemical properties of cell walls influence plant mineral nutrition, as nutrients do not simply pass through the apoplast to the plasmalemma but can also be adsorbed or fixed to cell‐wall components. Here, current progress in understanding the significance of the apoplast in plant mineral nutrition is reviewed. The contribution of the root apoplast to short‐distance transport and nutrient uptakes is examined particularly in relation to Na+ toxicity and Al3+ tolerance. The review extends to long‐distance transport and the role of the apoplast as a habitat for microorganisms. In the leaf, the apoplast might have benefits over the vacuole as a site for short‐term nutrient storage and solute exchange with the atmosphere.

Contents

Summary
167

I.
Introduction
168

II.
The properties of the apoplast and its implication for solute movement
168

1. The middle lamella
168

2. The primary wall
168

3. The secondary cell wall
169

III.
The root apoplast – nutrient uptake and short‐distance transport
170

IV.
The apoplast as a compartment for long distance transport
174

V.
The apoplast – habitat for microorganisms
175

VI.
The apoplast of leaves – a compartment of storage and of reactions
177

1. Transport routes in the leaf apoplast
177

2. Methods of studying apoplastic solutes
177

3. Solute relations in the leaf apoplast
178

4. Concentration gradients in the leaf apoplast
179

5. Ion relations in the leaf apoplast and symptoms of deficiency and toxicity
179

6. Ion relations in the leaf apoplast – influence of nutrient supply
180

7. The leaf apoplast – compartment for transient ion storage
180

8. Ion fluxes between apoplast and symplast
181

9. Apoplastic ion balance
181

10. Leaf apoplast – interaction with the atmosphere
183

VII.
Conclusions
183

Acknowledgements
183

References
183
Invertase protein, but not activity, is present throughout development of Lycopersicon esculentum and L.pimpinellifolium fruit
Authors: Husain Sarah E. , Thomas Barry J. , Kingston‐Smith Alison H. , Foyer Christine H.
Published: March 2003

The presence and distribution of invertase is reported in two red fruited and hexose accumulating species of tomato, Lycopersicon esculentum
and
L. pimpinellifolium , which differ markedly in fruit invertase activity.

Using antibodies raised against a highly conserved invertase peptide, all invertase isoforms in green and red tomato fruit were detected and visualized by chemi luminescence and western blotting techniques. Interacellular localization of invertase was examined by electron and light microscopy.

Invertase activities were much lower in green fruit than in red fruit from all cultivars. However, invertase protein was evenly distributed between all tissues of green and red fruit in tissue blots that had been extensively treated with preimmune serum that eliminated all non‐specific binding. Immuno‐gold labelling showed that invertase protein was present in the cell wall and vacuole, but not in the cytosol, of epidermal tissue from both species.

Invertase protein is present throughout fruit development in tomato. However, the increase in activity during ripening is due to changes in the activation state of the protein rather than the amount of protein present.
Manipulation of fruit sugar composition but not content in Lycopersicon esculentum fruit by introgression of an acid invertase gene from Lycopersicon pimpinellifolium
Authors: Husain S. E. , James C. , Shields R. , Foyer Christine H.
Published: March 2003

The effects are shown here of genetic manipulation of invertase on fruit sugar metabolism in tomato.

Introgression of the acid invertase gene on chromosome 3 from Lycopersicon pimpinellifolium
(an accession containing high invertase activity) into
Lycopersicon esculentum (with relatively low activity) was used to study effects on fruit development and both sugar composition and content.

The L. pimpinellifolium
parent fruit had higher fruit invertase activities, greater hexose contents and lower sucrose accumulation that the
L. esculentum
parent. A strong correlation between fruit invertase activity and soluble sugar content was observed only in the
L. pimpinellifolium parent and not in the homozygous fruit from either cross. In all cases high soluble acid invertase activities prevented sucrose accumulation and led to the build‐up of hexoses.

The introgression of the invertase locus from L. pimpinellifolium
into
L. esculentum
did not result in higher soluble solids in the progeny than in the
L. esculentum parent, but it did modify their relative composition. Changes in the invertase gene composition alone are not sufficient to increase fruit soluble solids in tomato.
Simultaneous, bidirectional translocation of 32P and 33P between wood blocks connected by mycelial cords of Hypholoma fasciculare
Authors: Lindahl Björn , Finlay Roger , Olsson Stefan
Published: March 2003

Translocation of nutrients through fungal mycelia has mainly been viewed in terms of unidirectional movement from sources to sinks. This paper describes an experiment designed to test the possibility of bidirectional phosphorus transport in mycelial cords of the white rot fungus Hypholoma fasciculare growing in soil microcosms.

A novel technique is described that uses the different energy spectra of the radioactive phosphorus isotopes 32
P and
33 P, in combination with nondestructive electronic autoradiography, to monitor the distribution of the two isotopes within single mycelial cord systems. The tracer isotopes were applied to pairs of wood blocks connected by mycelial cords, and isotope translocations were monitored during a 29‐d period.

Significant amounts of phosphorus were transported in both directions simultaneously between the two colonized wood blocks.

Simultaneous, bidirectional translocation of phosphorus occurs in mycelial cords of H. fasciculare . Such circulation of nutrients in fungal mycelia should equalize differences in nutrient concentrations in different parts of the mycelia, enabling net translocation of nutrients from areas of high nutrient availability to those of high nutrient demand.
Growth and nitrogen uptake of CO2‐enriched rice under field conditions
Authors: Kim H. Y. , Lieffering M. , Miura S. , Kobayashi K. , Okada M.
Published: March 2003

The effects of elevated CO2 are reported here on the uptake of nitrogen (N) and its relationships with growth and grain yield in rice (Oryza sativa).

 Using free‐air CO2 enrichment (FACE), rice crops were grown at ambient or elevated (c. 300 µmol mol−1 above ambient) CO2 and supplied with low, medium or high levels of N.

 For the medium and high N treatments, FACE increased N uptake at panicle initiation but not at maturity. For total dry matter, as well as spikelet number and grain yield, positive interactions between CO2 and N uptake were observed. Furthermore, spikelet number was closely associated with N uptake at panicle initiation.

 These results indicate that, to maximize rice grain yield under elevated CO2, it is important to supply sufficient N over the whole season, in order to maintain the enhancement in dry matter production. In addition, N availability must be coordinated with the developmental stage of the crop, specifically to ensure that sufficient N is available at panicle initiation in order to maximize spikelet number and grain yield.
Developmental cross talking in the ectomycorrhizal symbiosis: signals and communication genes
Authors: Martin Francis , Duplessis Sébastien , Ditengou Frank , Lagrange Hubert , Voiblet Catherine , Lapeyrie Frédéric
Published: March 2003

Development of ectomycorrhizas involves multiple genes that are implicated in a complex series of interdependent, sequential steps. Current research into ectomycorrhiza development and functioning is aimed at understanding this plant–microbe interaction in a framework of the developmental and physiological processes that underlie colonization and morphogenesis. After a brief introduction to the ectomycorrhizal symbiosis, the present article highlights recent work on the early signal exchange taking place between symbionts, and sketches the way functional genomics is altering our thinking about changes in gene expression during the early steps of the ectomycorrhiza development.
Reproduction and offspring competitiveness of Senna obtusifolia are influenced by nutrient availability
Authors: Tungate Kimberly D. , Susko David J. , Rufty Thomas W.
Published: March 2003

• Senna obtusifolia (sicklepod) is a troublesome weed in many agronomic cropping systems in the southeastern USA with varying fertility regimes. This series of experiments was initiated to determine the impact of nutrient availability on reproductive output and maternal effects.

• Experiments were conducted with plants growing in soil in growth chambers for 120 d. Offspring growth was evaluated in hydroponics.

• Plants grown under higher nutrient conditions had greater reproductive biomass, number of seeds and total seed biomass. Individual seed mass distributions were slightly affected, with negative skewness decreased at higher nutrition. Seed germination rates were influenced primarily by seed size, as small seeds germinated faster than large seeds. The nitrogen content of seeds increased with increasing seed size and was higher in the high nutrition treatment. Seedlings arising from maternal plants grown under high nutrition grew more rapidly than did seedlings arising from maternal plants grown in a low nutrient regime.

• The results suggest that S. obtusifolia reproduction and offspring competitiveness can be strongly influenced by the fertilization regimes used in different agronomic crops and rotations.
Ectomycorrhizal fungal communities in young forest stands regenerating after clearcut logging
Authors: Jones Melanie D. , Durall Daniel M. , Cairney John W. G.
Published: March 2003

The effects on the ectomycorrhizal fungal community of clearcut logging, which is used to harvest millions of hectares of ectomycorrhizal forest annually, has been studied for a number of years. Here, we review current knowledge of inoculum sources for ectomycorrhizal fungi in forests and then re‐examine earlier studies of ectomycorrhizas on young trees in regenerating stands. We conclude that, taken separately from the effects of site preparation, the major impact of clearcut logging is to change the species composition of the ectomycorrhizal fungal community rather than to reduce the percentage of roots colonized. A thorough examination of site preparation treatments suggests that the changes in fungal species composition are driven by changes in the biology and chemistry of the soil environment after clearcutting as much as they are by loss or change in fungal inoculum. This is an important conclusion because it implies that these new ectomycorrhizal fungal communities are better adapted to the new conditions than the ones in the forest would have been. The shift in fungal species composition and diversity will have implications for seedling establishment and competition. The effects of individual fungi or diverse assemblages of fungi on seedling growth, and effects of changes in the ability of young trees to associate with a common mycelium are discussed.ContentsSummary399I.Introduction400II.Population biology and inoculum potential of ectomycorrhizal fungi401III.Ectomycorrhiza development on seedlings regenerating after clearcut logging402IV.Which is the most important factor driving changes in the ECM fungal community after clearcut logging: inoculum loss or change in the below‐ground environment?406V.Possible consequences for regenerating stands of species shifts in ectomycorrhizal fungi414VI.Conclusions416
Consumer Support Networks: improving consumer advice in the UK
Authors: Brennan Carol , Gallagher Kelly
Published: March 2003

In 1999, Central Government launched an initiative to establish Consumer Support Networks (CSNs) throughout Scotland, England and Wales. The purpose of the networks is to improve access to high quality consumer advice services. Information and advice agencies will join together to provide expert, accurate and timely advice for consumers. By April 2002, 191 networks had been established covering in excess of 99% of the population. Only one local authority area in England has yet to establish a network. This paper reviews the development of consumer information and advice provision in the UK and considers the context for establishing CSNs. It also examines the need for consumer advice, the role of Central Government and the quality framework. Each CSN will conduct a gap analysis and assess the need for consumer advice in the local area. This will enable the network to develop a good understanding of consumers in the area and to take a more strategic approach in planning service developments to meet the identified needs. Consumer Support Networks aim to improve the provision of consumer information, education and advice. The literature suggests that consumers who are well educated regarding their rights are empowered through an increased ability to exercise them. Clearly branded advice services, marketed effectively to the public should result in higher levels of consumer awareness and, consequently, improve access to services. It is also expected that better flows of information between agencies will result in greater protection for consumers. Sharing ‘best practice’ nationwide should stimulate service improvements throughout.
Associations between demographics and perceptions of unethical consumer behaviour
Authors: Callen Karen S. , Ownbey Shiretta F.
Published: March 2003

Retailers may lose profits as a result of shoplifting and other unethical consumer behaviour. Research focusing on consumer ethical decision making is needed. Information provided by 1117 undergraduate students from universities within the US revealed that women are less accepting of unethical consumer behaviour than men. Subjects who reported that they very consistently follow the teachings of their primary faith are less accepting of unethical consumer behaviour than subjects who reported that they do not very consistently follow the teachings of their primary faith. Relationships between consumer ethical response scores and other demographic characteristics are discussed.
Determination of cholesterol in dairy products using infrared techniques: 1. FTIR spectroscopy
Authors: Paradkar Manish M , Irudayaraj Joseph
Published: March 2003

A Fourier transformed infrared (FTIR) spectroscopic method is described to estimate cholesterol after a single step extraction instead of the conventional colorimetric method. FTIR spectrum of pure cholesterol was characterized and the region between 2800 and 3200 cm−1 was used for quantitative estimation. Partial least square (PLS) and principal component regression (PCR) analysis were used for quantitative analysis. FTIR spectroscopy with chemometrics could predict the cholesterol content accurate to an r2 greater than 0.99 and a standard error of prediction (SEP) of less than 0.98. The developed model was successfully applied to predict cholesterol in commercial dairy products and validated with standard method and recovery studies. Results indicate that FTIR spectroscopy can determine the cholesterol content in dairy products in approximately 5 min.
Aerobic spore‐forming bacteria in bulk raw milk: factors influencing the numbers of psychrotrophic, mesophilic and thermophilic Bacillus spores
Authors: McGuiggan James T M , McCleery David R , Hannan Alan , Gilmour Arthur
Published: March 2003

Psychrotrophic, mesophilic and thermophilic spore concentrations of Bacillus spp. were determined on a weekly basis in bulk raw milk samples obtained from a central processing facility, over one calendar year. These data were correlated with concentrations of metal ions, free amino acids and somatic cell counts obtained from the same samples, as well as local meteorological mean temperature and relative humidity measurements relating to the same test period. A heat treatment of 80°C for 20 min followed by the addition of L‐alanine to the milk at 0.1% w/v and incubation at 55°C for 7 days gave optimal recovery conditions for thermophilic spores. Free amino acids, metal ions, somatic cell counts, temperature, and relative humidity measurements were each significantly correlated with the recovery of spores of Bacillus spp. from bulk raw milk, although no single factor was shown to demonstrate a consistent effect with the psychrotrophic, mesophilic and thermophilic spore groups studied.
A 5‐star system for rating the quality of information based on DISCERN
Authors: Shepperd Sasha , Charnock Deborah , Cook Adrian
Published: March 2003

Objective: To develop an explicit scheme for calculating a 5‐star quality rating for consumer health information, and to test if there is good agreement be tween this and the final DISCERN quality question.

Design: A sample of 15 consumers and health professionals rated 26 health information leaflets covering a broad range of conditions and treatments using two new 5‐star‐rating schemes and the existing DISCERN final quality rating. Each scheme is based on the 15 DISCERN criteria, but the 5‐star schemes provide more explicit methods for summarizing overall quality. The level of agreement between the three different rating systems was compared using Kappa scores with quadratic weights. Participants were also asked to complete a brief questionnaire that was designed to elicit their views on using a visual summary of the quality of health information.

Results: The level of agreement between each 5‐star‐rating system and the existing DISCERN quality rating question was high (kappa = 0.86, 95% CI 0.83–0.89 in both instances). Seventy‐seven per cent of the sample preferred the second star‐rating scheme, and 80% reported they would use such a scheme.

Conclusion: Assigning a single quality score using an explicit scoring scheme (represented by stars) based on answers to the DISCERN questionnaire is a reliable and valid way of rating consumer health information.
HealthCyberMap: a semantic visual browser of medical Internet resources based on clinical codes and the human body metaphor
Authors: Kamel Boulos Maged N. , Roudsari Abdul V. , Carso n Ewart R.
Published: March 2003

Objectives: HealthCyberMap (HCM—http://healthcybermap.semanticweb.org) is a web‐based service for healthcare professionals and librarians, patients and the public in general that aims at mapping parts of the health information resources in cyberspace in novel ways to improve their retrieval and navigation.

Methods and service description: HCM adopts a clinical metadata framework built upon a clinical coding ontology for the semantic indexing, classification and browsing of Internet health information resources. A resource metadata base holds information about selected resources. HCM then uses GIS (Geographic Information Systems) spatialization methods to generate interactive navigational cybermaps from the metadata base. These visual cybermaps are based on familiar medical metaphors.

Conclusions: HCM cybermaps can be considered as semantically spatialized, ontology‐based browsing views of the underlying resource metadata base. Using a clinical coding scheme as a metric for spatialization (‘semantic distance’) is unique to HCM and is very much suited for the semantic categorization and navigation of Internet health information resources. Clinical codes ensure reliable and unambiguous topical indexing of these resources. HCM also introduces a useful form of cyberspatial analysis for the detection of topical coverage gaps in the resource metadata base using choropleth (shaded) maps of human body systems.
The Structure and Function of Myelin Oligodendrocyte Glycoprotein
Authors: Johns Terrance G. , Bernard Claude C. A.
Published: March 2003

Abstract : Myelin oligodendrocyte glycoprotein (MOG) is a quantitatively minor component of CNS myelin whose function remains relatively unknown. As MOG is an autoantigen capable of producing a demyelinating multiple sclerosis‐like disease in mice and rats, much of the research directed toward MOG has been immunological in nature. Although the function of MOG is yet to be elucidated, there is now a relatively large amount of biochemical and molecular data relating to MOG. Here we summarize this information and include our recent findings pertaining to the cloning of the marsupial MOG gene. On the basis of this knowledge we suggest three possible functions for MOG : (a) a cellular adhesive molecule, (b) a regulator of oligodendrocyte microtubule stability, and (c) a mediator of interactions between myelin and the immune system, in particular, the complement cascade. Given that antibodies to MOG and to the myelin‐specific glycolipid galactocerebroside (Gal‐C) both activate the same signaling pathway leading to MBP degradation, we propose that there is a direct interaction between the membrane‐associated regions of MOG and Gal‐C. Such an interaction may have important consequences regarding the membrane topology and function of both molecules. Finally, we examine how polymorphisms and/or mutations to the MOG gene could contribute to the pathogenesis of multiple sclerosis.
Immunohistochemical Distribution of RGS7 Protein and Cellular Selectivity in Colocalizing with Gαq Proteins in the Adult Rat Brain
Authors: Khawaja Xavier Z. , Liang Jin‐Jun , Saugstad Julie A. , Jones Philip G. , Harnish Steven , Conn P. Jeffrey , Cockett Mark I.
Published: March 2003

Abstract : Regulators of G protein signaling (RGS) proteins serve as potent GTPase‐activating proteins for the heterotrimeric G proteins αi/o and αq/11. This study describes the immunohistochemical distribution of RGS7 throughout the adult rat brain and its cellular colocalization with Gαq/11, an important G protein‐coupled receptor signal transducer for phospholipase Cβ‐mediated activity. In general, both RGS7 and Gαq/11 displayed a heterogeneous and overlapping regional distribution. RGS7 immunoreactivity was observed in cortical layers I‐VI, being most intense in the neuropil of layer I. In the hippocampal formation, RGS7 immunoreactivity was concentrated in the strata oriens, strata radiatum, mossy fibers, and polymorphic cells, with faint to nondetectable immunolabeling within the dentate gyrus granule cells and CA1‐CA3 subfield pyramidal cells. Numerous diencephalic and brainstem nuclei also displayed dense RGS7 immunostaining. Dual immunofluorescence labeling studies with the two protein‐specific antibodies indicated a cellular selectivity in the colocalization between RGS7 and Gαq/11 within many discrete brain regions, such as the superficial cortical layer I, hilus area of the hippocampal formation, and cerebellar Golgi cells. To assess the ability of Gαq/11‐mediated signaling pathways to modulate dynamically RGS expression, primary cortical neuronal cultures were incubated with phorbol 12,13‐dibutyrate, a selective protein kinase C activator. A time‐dependent increase in levels of mRNA for RGS7, but not RGS4, was observed. Our results provide novel information on the region‐ and cell‐specific pattern of distribution of RGS7 with the transmembrane signal transducer, Gαq/11. We also describe a possible RGS7‐selective neuronal feedback adaptation on Gαq/11‐mediated pathway function, which may play an important role in signaling specificity in the brain.
Administration of Dexamethasone Up‐Regulates Protein Kinase C Activity and the Expression of γ and ε Protein Kinase C Isozymes in the Rat Brain
Authors: Dwivedi Yogesh , Pandey Ghanshyam N.
Published: March 2003

Abstract : Altered hypothalamic‐pituitary‐adrenal (HPA) function
(increased plasma cortisol level) has been shown to be associated with mood
and behavior. Protein kinase C (PKC), an important component of the
phosphatidyl‐inositol signal transduction system, plays a major role in
mediating various physiological functions. The present study investigates the
effects of acute (single) and repeated (10‐day) administrations of 0.5 or 1.0
mg/kg doses of dexamethasone (DEX), a synthetic glucocorticoid, on
Bmax and KD of [3H]phorbol
12,13‐dibutyrate ([3H]PDBu) binding, PKC activity, and protein
expression of PKC isozymes, α, β, γ, δ, and ε in
the membrane and the cytosolic fractions of rat cortex and hippocampus. It was
observed that repeated administration of 1.0 mg/kg DEX for 10 days caused a
significant increase in Bmax of [3H]PDBu binding to PKC, in PKC activity, and in expressed protein levels of the γ and ε isozymes in both the cytosolic and the membrane fractions of the cortex and the hippocampus, whereas a lower dose of DEX (0.5 mg/kg for 10 days) caused these changes only in the hippocampus. On the other hand, a single administration of DEX (0.5 or 1.0 mg/kg) had no significant effect on PKC in the cortex or in the hippocampus. These results suggest that alterations in HPA function from repeated administration of glucocorticoids may modulate PKC‐mediated functions.
Inhibition of Calcium‐Dependent NMDA Receptor Current Rundown by Calbindin‐D28k
Authors: Price Christopher J. , Rintoul Gordon L. , Baimbridge Kenneth G. , Raymond Lynn A.
Published: March 2003

Abstract : NMDA receptors are regulated by several different
calcium‐dependent processes. To determine if the presence of the intracellular
calcium‐binding protein calbindin‐D28k can influence the calcium regulation of NMDA receptor activity,human embryonic kidney 293 cells were co‐transfected with cDNAs for NMDA receptor subunits and cablinding. Recordings were made using the nystatin perforated patch technique to preserve intracellular contents. When compared with control cells (transfected with cDNA enconding β‐galactosidase in place of calbindin), the presence of calbindin had no effect on either calcium‐dependent inactivation or the calciumsensitive, time‐dependent increase in glycine‐independent desensitization of NMDA receptor‐mediated currents. However, the development of calcium‐dependent rundown of peak glutamate‐evoked current was slowed significantly in calbindin versus β‐galactosidase cotransfected cells. This result was true for cells transfected with either NR1/NR2A or NR1/NR2B subunits, although calbindin was relatively less effective at inhibiting rundown in NR1/NR2B‐expressing cells. NMDA peak current rundown has been attributed to calcium‐induced depolymerization of the actin cytoskeleton. Therefore, our results indicate that although calbindin may not influence calcium‐dependent regulatory processes occurring very near the NMDA receptor channel, it appears to be more effective at buffering local elevations in intracellular calcium at the actin cytoskeleton.
Suppression of the Nicotinic Acetylcholine Response in Rat Superior Cervical Ganglionic Neurons by Steroids
Authors: Uki Motomichi , Nabekura Junichi , Akaike Norio
Published: March 2003

Abstract : The effects of various types of steroids on the nicotinic
acetylcholine (ACh) receptor (nAChR)‐mediated responses were investigated in
superior cervical ganglionic neurons acutely dissociated from rats using
nystatin perforated patch recording. ACh induced a peak followed by a gradual
decrease in the inward current at a holding potential of ‐40 mV. Nicotine, but
not muscarine, mimicked ACh. Hydrocortisone at a concentration of >
10‐6M reversibly suppressed both the peak and
steady‐state nicotine‐induced currents (Inic) in a
noncompetitive manner. The inhibition of Inic by
hydrocortisone did not show any voltage dependency and persisted in the
presence of either cyclic AMP modulators, forskolin and
3‐isobutyl‐1‐methylxanthine, or a protein kinase A inhibitor,
N‐[2‐(methylamino)ethyl]‐5‐isoquinolinesulfonamide dihydrochloride
(H‐89). β‐Estradiol, androsterone, aldosterone, and 17α‐estradiol
mimicked hydrocortisone in its inhibitory action on ACh‐induced currents
(IACh). The potency for the inhibitory actions on
IAch was as follows : androsterne > β‐estradiol
> hydrocortisone ≥ aldosterone =17α‐estradiol. Cholesterol had no
effect on the IACh. In conclusion, the structural
characteristics of steroid are thus considered to be necessary to block
nicotinic IACh in rat superior cervical ganglionic cells, whereas the cholesterol side chain might disturb the inhibitory action of the steroid skeleton on nAChRs.