bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of a real‐time PCR method to detect Pyrenophora species in barley seed, and implications for seed treatment strategies*
Authors: Thomas J. E. , Taylor E. J. A. , Bates J. A. , Kenyon D. M.
Published: April 2008

DNA primer sequences and the polymerase chain reaction (PCR) were used to detect the presence of Pyrenophora graminea and P. teres on barley seeds. The PCR was carried out in a Lightcycler with real‐time measurement of the product using a fluorescent dye. P. teres infection was quantified, while P. graminea infection was determined as present or absent. Test results were available within 48 h. Seed treatments to control both species are commonly used in the UK, though recent results indicated that P. graminea occurs infrequently, while incidence of P. teres is more variable. Rapid seed‐health testing techniques offer the potential for improved targeting of seed treatment without delaying the processing of seed.
Specific identification of Aureobasidium pullulans strain L47 using Scorpion PCR*
Authors: Schena L. , Sialer M. M. Finetti , Gallitelli D.
Published: April 2008

Strain L47 of Aureobasidium pullulans is an effective biocontrol agent for several post‐harvest fruit diseases, even when applied in the field before harvesting. This strategy requires a specific method of monitoring in order to optimize formulations and to evaluate the level of colonization and dispersal in the environment. We have detected strain L47 among other morphologically indistinguishable isolates of A. pullulans using Scorpion PCR, an automated real‐time fluorescence detection system that targets a 145‐bp fragment of the L47 genome. We propose this approach as a specific, rapid and reliable method of monitoring A. pullulans, strain L47.
Detection of nematode antagonistic bacteria by fluorogenic molecular probes*
Authors: Ciancio A. , Leonetti P. , Sialer M. M. Finetti
Published: April 2008

Last‐generation DNA probes include molecules yielding a fluorogenic emission through an intramolecular change occurring after hybridization to a complementary sequence. They display a high sequence specificity and may detect even single‐base mutations in polymerase chain reaction (PCR) amplification products. We applied Scorpion primers for the detection of an unculturable nematode‐parasitic bacterium, Pasteuria sp., with potential as a biological control agent. A 16S rDNA oligonucleotide sequence unique to Pasteuria spp. was used to detect the parasite in juveniles of Heterodera goettingiana or in soil. The parasitized nematodes came from a population with a Pasteuria prevalence of 40–80% and were individually checked for parasitism. Probes with 6‐carboxy‐fluorescein (FAM) at the 5’terminus, used for PCR with nematodes or soil, successfully detected the parasite from both samples. The amplification of the expected 139bp fragment was shown both by fluorescence observed under UV excitation in the eppendorfs and by gel electrophoresis of the corresponding amplicons. The potential of this detection method for the study of unculturable bacteria is discussed.
Reliable identification of the quarantine root‐knot nematodes Meloidogyne chitwoodi and M. fallax by PCR‐based techniques*
Authors: Zijlstra C.
Published: April 2008

The root‐knot nematodes Meloidogyne chitwoodi and M. fallax have been declared quarantine pests in Europe and there is a growing need for practical, reliable techniques to identify these nematodes and distinguish them from M. hapla. Such methods are needed for plant resistance management and research, for design of crop rotation systems and for inspection of harvested crops or soil samples. At the moment, several PCR‐based techniques have been developed, based on rDNA and SCAR primers. Some of these methods can be applied for extremely sensitive detection of a specific species, enabling the detection of 0.001 juvenile or less. These can also detect specific species present in mixtures in proportions of less than 1%. Others enable a precise estimation of the species composition in mixtures and can detect species present in mixtures in proportions as low as 5%. Depending on the question to be asked and the source of the sample to be studied, optimal diagnostic assays can be created by combining relevant methods.
Modern methods for identification of Thysanoptera*
Authors: Moritz G. , Delker C. , Paulsen M. , Mound L. A. , Burgermeister W.
Published: April 2008

An interactive key is described for larvae and adults of economically important species of thrips. This is based on computerized photographs (Automontage), video clips and an interface to a molecular key for larvae based on ITS‐RFLP analysis.
Rapid field detection of Ralstonia solanacearum in infected tomato and potato plants using the Staphylococcus aureus slide agglutination test
Authors: Lyons N. , Cruz L. , Santos M. Sousa
Published: April 2008

Ralstonia solanacearum is the major cause of bacterial wilt, which affects over 200 species of plants, many of economic importance. Current methods for detection and identification of the pathogen rely on isolation on semi‐selective media followed by a combination of serological and molecular techniques and plant inoculation. Such methods are time‐consuming, and require extensive laboratory facilities and skilled personnel. A reliable and rapid screening technique, which could be applied in the field, would reduce the number of samples submitted for laboratory testing and provide a vital component in disease control measures. A programme for the control of R. solanacearum has been introduced in Portugal and a Staphylococcus aureus slide agglutination test was used directly on tomato and potato plants in the field and on bacterial cultures under laboratory conditions. The results obtained show that this technique can play a major role in control programmes by providing a sensitive tool for the rapid detection of the pathogen.
Viruses and viroids of stone fruits in Jordan
Authors: Al. Rwahnih M. , Myrta A. , Abou‐Ghanem N. , Di Terlizzi B. , Savino V.
Published: April 2008

Field surveys were carried out in the main stonefruit‐growing areas of Jordan to assess the sanitary status of varietal collections, mother plant blocks and commercial orchards. The presence of virus and virus‐like diseases was determined by ELISA, sap transmission to herbaceous hosts, graft transmission to Prunus persica cv. GF 305 and P. serrulata cv. Kwanzan, and molecular hybridization tests. A total of 1312 samples was tested by ELISA (531 peach, 361 plum, 218 apricot, 135 almond and 67 cherry trees). The overall mean level of infection was about 14%, indicating an acceptable sanitary status as a whole, considering that no sanitary selection has ever been carried out in Jordan. The infection level of different species was: peach (18%), cherry (15%), almond (14%), apricot (11%) and plum (10%). The following viruses and viroids were identified: Plum pox potyvirus (PPV), Prunus necrotic ringspot ilarvirus (PNRSV), Prune dwarf ilarvirus (PDV), Apple mosaic ilarvirus (ApMV), Apple chlorotic leaf spot trichovirus (ACLSV), Hop stunt viroid (HSVd) and Peach latent mosaic viroid (PLMVd). Most of these agents (ApMV, ACLSV, PLMVd and HSVd) are reported for the first time from Jordan.
Importance de la maladie du charbon causée par Ustilago scitaminea sur canne à sucre dans la plaine du Gharb (Maroc)
Authors: Nadif A. , Zaizouni M. , Mohamed M. Ouahidi
Published: April 2008

L'apparition de la maladie du charbon sur la canne à sucre marocaine en 1993 a coïncidé avec la prédominance dans cette culture des génotypes particulièrement sensibles. Une grande épidémie s'est alors déclenchée dans l'un des deux principaux périmètres du royaume. Les infections se sont étendues en un laps de temps assez court sur toutes les superficies cultivées. Ce n'est que vers l'année 1999 qu'une première régression de la propagation de la maladie est enregistrée. Cela est le fruit de la libération de nouveaux cultivars résistants issus des essais de sélection menés par le Centre Technique des Cultures Sucrières (CTCS), principal organisme chargé de la promotion de la canne à sucre dans le pays. Le présent article retrace la dernière situation des infections par localité, cultivar et degré d'infection telle qu'elle a été déterminée suite à des prospections de grande envergure menées par toute la profession à travers le périmètre du Gharb.
Relation entre I'infestation de Tylenchulus semipenetrans, la morphogenèse et la productivité de l'oranger cv. Maltaise demisanguine greffées sur bigaradier
Authors: Kallel S. , Jaziri A. , B'Chir M. M.
Published: April 2008

Les variations pluriannuelles de la croissance végétative (orthotrope et plagiotrope) et de la production et du taux d'infestation des citrus par Tylenchulus semipenetrans suivent une évolution cyclique et des amplitudes décalées les unes par rapport aux autres. Ces variations présentent deux phases distinctes. La première se caractérise par une diminution de la population des nématodes dans les racines, une augmentation de la croissance plagiotrope aux dépens de la croissance orthotrope et une production annuelle stable. La deuxième phase se caractérise par contre par une augmentation de l'infestation, une croissance orthotrope plus dominante et une alternance annuelle de la production des agrumes. L'intervention chimique à l'aldicarbe permet de réduire l'incidence des nématodes sur les agrumes, mais seuls les traitements appliqués au cours de la deuxième phase sont efficaces contre les nématodes.
Crown gall on Eucalyptus occidentalis seedlings
Authors: Krimi Z.
Published: April 2008

Agrobacterium tumefaciens has been isolated from 2‐year‐old seedlings of Eucalyptus occidentalis growing in forest soil in Algeria.
First report of a geminivirus causing leaf curl disease on Trigonella corniculata evidenced by PCR using degenerate primers
Authors: Raj S. K. , Pandey S. K. , Chandra G. , Singh B. P. , Gupta R. K.
Published: April 2008

A leaf curl and mottle disease was observed naturally affecting plants of Trigonella corniculata. A geminivirus was detected in infected plants by PCR using degenerate geminivirus primers and by Southern hybridization with a probe specific to tomato leaf curl begomovirus. This is the first report of a member of the Geminiviridae naturally occurring in T. corniculata.
Comparison of the effectiveness of five extraction methods for Clavibacter michiganensis subsp. sepedonicus and Ralstonia solanacearum from potato tubers
Authors: Martin J. , Beaumanoir N.
Published: April 2008

In the EU Control Directives, the recommended extraction procedure for testing potatoes for Clavibacter michiganensis subsp. sepedonicus and Ralstonia solanacearum comprises incubation followed by differential centrifugation. This method can be qualified as complex because of the number of different steps required. This study evaluates five different extraction methods for each bacterium from both a technical point of view and for the quality of the results. Results showed that in the case of C. m. sepedonicus the clarification step should be avoided. The incubation/shaking method with three subsamples gives at least as satisfactory results as the official EU procedure. It also has other advantages, facilitating immunofluorescence readings due to the reduced quantity of plant debris, and improving the speed and the reliability of the analysis.
Microbiological tests of the effects of plant protection products in soil: experience and proposals to improve ecotoxicological significance
Authors: Malkomes H.‐P.
Published: April 2008

One objective of ecotoxicological testing of plant protection products within authorization procedures is to assess, under standardized conditions, potential risks for soil microorganisms. This is only possible if some essential conditions are considered. In the past 10 years, experience has been obtained, either from authorization procedures or ecotoxicological research, which may stimulate discussion of existing or planned test methods. This includes applied microbiological test parameters (e.g. sensitivity, significance), design of the tests (e.g. dosage, mode of application, reference compounds, soils, ecological conditions, incubation time) as well as the interpretation of results. The size of tests is necessarily reduced in routine authorization procedures as compared with those within ecotoxicological research and these tests must therefore be optimized and updated to reach sufficient efficiency. From our experience, the combination of biomass‐related microbial activities (e.g. substrate‐induced respiration, dehydrogenase activity) with nitrogen transformation (mineralization followed by nitrification) is especially useful to identify dose‐dependent effects.
The western corn rootworm (Diabrotica virgifera virgifera): a new maize pest threatening Europe
Authors: Berger H. K.
Published: April 2008

The western corn rootworm Diabrotica virgifera virgifera is one of the most dangerous pests in maize in the USA. For many years, US growers have had to control this pest in maize fields by soil treatment or spraying. Ten years ago, this pest was also ‘imported’ into Europe. It was the job of the plant protection advisers and officials to inform endangered countries about the appearance of this pest, to develop control strategies for Europe and to establish research programmes to prevent further spread. This paper presents the history of this pest in Europe, its biology, the situation in 2001 and corn rootworm management scenarios for the future.
Use of the DNA sequence of the intergenic spacer region between the 16S and 23S rRNA genes for the identification of Clavibacter michiganensis subsp. insidiosus at the molecular level
Authors: Borowicz B. P.
Published: April 2008

A study has been performed to identify Clavibacter michiganensis subsp. insidiosus at the molecular level, using the polymerase chain reaction (PCR) technique with oligonucleotide primers based on specific sequence recognition of the intergenic spacer region between the 16S and 23S rRNA genes. The pair of primers was designed on the basis of available DNA sequence data for that region in C. m. insidiosus and other bacteria. Using this pair of primers, a large amount of an amplified DNA fragment of 218 bp in length was obtained from C. m. insidiosus. The specificity of this amplification was proved by PCR analysis, using the above‐mentioned pair of primers and templates from different bacteria, some related to C. m. insidiosus. The PCR products were analysed using agarose gel electrophoresis.
A survey of peach viruses in Lebanon
Authors: Choueiri E. , Haddad C. , Ghanem‐Sabanadzovic N. Abou , Jreijiri F. , Issa S. , Saad A. T. , Di Terlizzi B. , Savino V.
Published: April 2008

Field surveys were carried out in the main peach‐growing areas of Lebanon to assess the presence and distribution of viruses and viroids in commercial orchards. Field inspections were made in spring and summer 2000 to observe symptoms of virus and viroid diseases respectively. In total, 950 trees in 95 commercial plantings from three different regions of Lebanon (Bekaa Valley, Mount Lebanon and north Lebanon) were surveyed and sampled. Immunoenzymatic tests (DAS‐ELISA) were used to ascertain the presence of the following: Prunus necrotic ring spot ilarvirus (PNRSV), Prune dwarf ilarvirus (PDV), Apple mosaic ilarvirus (ApMV), Apple chlorotic leaf spot trichovirus (ACLSV), Plum pox potyvirus (PPV), Tomato ringspot nepovirus (ToRSV) and Strawberry latent ringspot nepovirus (SLRSV). Peach latent mosaic pelamoviroid (PLMVd) and Hop stunt hostuviroid (HSVd) were identified by molecular hybridization. About 25% of the tested samples were infected by one or more viruses. In particular, the prevailing virus was PNRSV (61.2% of infection), followed by ACLSV (27.1%), PDV (22.4%) and ApMV (2.1%). Mixed infections were about 13%. ToRSV, SLRSV and PPV were not found. HSVd was apparently absent, whereas PLMVd was identified in 34% of the samples examined. This viroid prevailed in certain areas of Mount Lebanon in both native and foreign cultivars.
Apparition en Tunisie de Fusarium oxysporum f. sp. radicis‐lycopersici, agent de la pourriture des racines et du collet de la tomate
Authors: Hajlaoui M. R. , Hamza N. , Gargouri S. , Guermech A.
Published: April 2008

Suite à l'observation d'une grave attaque touchant 16% de l'effectif d'une culture hydroponique de tomate sous serre dans le sud de la Tunisie en 2001–02/03, un Fusarium oxysporum a été isolé au niveau du pivot et du collet. Son identité a été vérifiée sur une série de cultivars différentiels. Il s'agit, pour la première fois en Tunisie, de Fusarium oxysporum f. sp. radicislycopersici, agent de la pourriture des racines et du collet de la tomate.
Non‐double‐couple mechanism of moderate earthquakes near Zakynthos, Greece, April 2006; explanation in terms of complexity
Authors: Zahradnik J. , Sokos E. , Tselentis G.‐A. , Martakis N.
Published: April 2008

Deviation of earthquakes from the double‐couple mechanism is an important, but delicate tool to study their source processes. For assessing the double‐couple percentage, the paper suggests to complement the standard least‐square moment‐tensor retrieval with a hierarchic spatio‐temporal grid search, progressively closer to the true source position and time. It enables identification of the double‐couple percentage convergence, while its limit is the resulting double‐couple percentage value, or range. The so‐called double‐couple percentage (DC%) versus correlation plots are introduced and difficulties of the double‐couple percentage assessment are discussed. It is proved that even close to the true source position, where the strike‐dip‐rake angles are already stable (within a few degrees), the double‐couple percentage may still vary by dozens of per cent. Moreover, even at the optimum spatial position, the double‐couple percentage estimate is extremely sensitive (0 to 100%) to small variations of the subevent origin time. This behaviour is explained in terms of the source complexity, implying a time‐dependent moment tensor. Therefore, the double‐couple percentage of complex events depends on the studied frequency band and, in general, also on the station azimuth. This explains broad variations of the double‐couple percentage reports among seismic agencies. Three earthquakes of mutually close epicentres were investigated (Zakynthos, Western Greece, April 2006, magnitudes ∼5.5) and a strong non‐double‐couple component of one of them was identified (double‐couple percentage of about 20%). Two equivalent models of this earthquake were found: a single‐event non‐ double‐couple model, and a double‐event model consisting of two double‐couple sources with highly different mechanisms.
Improved Monte Carlo inversion of surface wave data
Authors: Socco Laura Valentina , Boiero Daniele
Published: April 2008

Inversion of surface wave data suffers from solution non‐uniqueness and is hence strongly biased by the initial model. The Monte Carlo approach can handle this non‐uniqueness by evidencing the local minima but it is inefficient for high dimensionality problems and makes use of subjective criteria, such as misfit thresholds, to interpret the results. If a smart sampling of the model parameter space, which exploits scale properties of the modal curves, is introduced the method becomes more efficient and with respect to traditional global search methods it avoids the subjective use of control parameters that are barely related to the physical problem. The results are interpreted drawing inference by means of a statistical test that selects an ensemble of feasible shear wave velocity models according to data quality and model parameterization. Tests on synthetic data demonstrate that the application of scale properties concentrates the sampling of model parameter space in high probability density zones and makes it poorly sensitive to the initial boundary of the model parameters. Tests on synthetic and field data, where boreholes are available, prove that the statistical test selects final results that are consistent with the true model and which are sensitive to data quality. The implemented strategies make the Monte Carlo inversion efficient for practical applications and able to effectively retrieve subsoil models even in complex and challenging situations such as velocity inversions.
Cross‐correlation of random fields: mathematical approach and applications
Authors: Gouédard P. , Stehly L. , Brenguier F. , Campillo M. , Colin de Verdière Y. , Larose E. , Margerin L. , Roux P. , Sánchez‐Sesma F. J. , Shapiro N. M. , Weaver R. L.
Published: April 2008

Random field cross‐correlation is a new promising technique for seismic exploration, as it bypasses shortcomings of usual active methods. Seismic noise can be considered as a reproducible, stationary in time, natural source. In the present paper we show why and how cross‐correlation of noise records can be used for geophysical imaging. We discuss the theoretical conditions required to observe the emergence of the Green's functions between two receivers from the cross‐correlation of noise records. We present examples of seismic imaging using reconstructed surface waves from regional to local scales. We also show an application using body waves extracted from records of a small‐scale network. We then introduce a new way to achieve surface wave seismic experiments using cross‐correlation of unsynchronized sources. At a laboratory scale, we demonstrate that body wave extraction may also be used to image buried scatterers. These works show the feasibility of passive imaging from noise cross‐correlation at different scales.
Seismic and electromagnetic controlled‐source interferometry in dissipative media
Authors: Wapenaar Kees , Slob Evert , Snieder Roel
Published: April 2008

Seismic interferometry deals with the generation of new seismic responses by crosscorrelating existing ones. One of the main assumptions underlying most interferometry methods is that the medium is lossless. We develop an ‘interferometry‐by‐deconvolution’ approach which circumvents this assumption. The proposed method applies not only to seismic waves, but to any type of diffusion and/or wave field in a dissipative medium. This opens the way to applying interferometry to controlled‐source electromagnetic (CSEM) data. Interferometry‐by‐deconvolution replaces the overburden by a homogeneous half space, thereby solving the shallow sea problem for CSEM applications. We demonstrate this at the hand of numerically modeled CSEM data.
Seismic reflection coefficients of faults at low frequencies: a model study
Authors: Van Der Neut Joost , Sen Mrinal K. , Wapenaar Kees
Published: April 2008

We use linear slip theory to evaluate seismic reflections at non‐welded interfaces, such as faults or fractures, sandwiched between general anisotropic media and show that at low frequencies the real parts of the reflection coefficients can be approximated by the responses of equivalent welded interfaces, whereas the imaginary parts can be related directly to the interface compliances. The imaginary parts of low frequency seismic reflection coefficients at fault zones can be used to estimate the interface compliances, which can be related to fault properties upon using a fault model. At normal incidence the expressions uncouple and the complex‐valued P‐wave reflection coefficient can be related linearly to the normal compliance. As the normal compliance is highly sensitive to the infill of the interface, it can be used for gas/fluid identification in the fault plane. Alternatively, the tangential compliance of a fault can be estimated from the complex‐valued S‐wave reflection coefficient. The tangential compliance can provide information on the crack density in a fault zone. Coupling compliances can be identified and quantified by the observation of PS conversion at normal incidence, with a comparable linear relationship.
Increased pancreatic islet mass is accompanied by activation of the insulin receptor substrate‐2/serine‐threonine kinase pathway and augmented cyclin D2 protein levels in insulin‐resistant rats
Authors: Rafacho Alex , Ribeiro Daniele Lisboa , Boschero Antonio Carlos , Taboga Sebastião Roberto , Bosqueiro José Roberto
Published: April 2008

It is well known that glucocorticoids induce peripheral insulin resistance in rodents and humans. Here, we investigated the structural and ultrastructural modifications, as well as the proteins involved in beta‐cell function and proliferation, in islets from insulin‐resistant rats. Adult male Wistar rats were made insulin resistant by daily administration of dexamethasone (DEX; 1mg/kg, i.p.) for five consecutive days, whilst control (CTL) rats received saline alone. Structure analyses showed a marked hypertrophy of DEX islets with an increase of 1.7‐fold in islet mass and of 1.6‐fold in islet density compared with CTL islets (P < 0.05). Ultrastructural evaluation of islets revealed an increased amount of secreting organelles, such as endoplasmic reticulum and Golgi apparatus in DEX islets. Mitotic figures were observed in DEX islets at structural and ultrastructural levels. Beta‐cell proliferation, evaluated at the immunohistochemical level using anti‐PCNA (proliferating cell nuclear antigen), showed an increase in pancreatic beta‐cell proliferation of 6.4‐fold in DEX islets compared with CTL islets (P < 0.0001). Increases in insulin receptor substrate‐2 (IRS‐2), phosphorylated‐serine‐threonine kinase AKT (p‐AKT), cyclin D2 and a decrease in retinoblastoma protein (pRb) levels were observed in DEX islets compared with CTL islets (P < 0.05). Therefore, during the development of insulin resistance, the endocrine pancreas adapts itself increasing beta‐cell mass and proliferation, resulting in an amelioration of the functions. The potential mechanisms that underlie these events involve the activation of the IRS‐2/AKT pathway and activation of the cell cycle, mediated by cyclin D2. These adaptations permit the maintenance of glycaemia at near‐physiological ranges.
Modelling wildlife–human relationships for social species with mixed‐effects resource selection models
Authors: Hebblewhite Mark , Merrill Evelyn
Published: April 2008

Resource selection functions (RSF) have contributed to the conservation of species negatively affected by human activities. Despite these applications, two assumptions frequent many studies: the assumption of independence among groups in social species, and that selection is proportional to resource availability. This latter case is known as a functional response in resource selection, and may be especially important in human–wildlife relationships where there is a fitness cost of proximity to humans.

Recent advances in generalized linear mixed models offer new ways to account for resource selection in social species and functional responses by accommodating correlations within hierarchical groups with random intercepts, and functional responses with random coefficients.

We illustrate the application of mixed‐effects RSF models using a case study of resource selection by individual wolves Canis lupus living in packs as a function of human activity.

In areas of low human activity, wolf resource selection was independent of proximity to humans. As human activity increased, wolves displayed a functional response selecting areas closer to human activity. With increasing human activity, however, wolves displayed spatio‐temporal avoidance of human activity during daylight. This could lead to behaviourally induced trophic cascades mediated by wolf avoidance of human activity, and fits within the framework of attractive sink habitats.

Accounting for the hierarchical social structure of wolves clearly showed that the response of wolves to human disturbance was strongly correlated, but different, within packs, and that the correlation was strongest during winter and weakest during summer.

Syntheses and applications. Failure to consider the social structure of wolves and the functional response to human activity would result in mistaken conclusions about wolf–human relationships. Our approach provides a unifying framework to understand the contradictory results of previous studies of wolf–human relationships and a template for future studies to evaluate effects of increasing human activity on wildlife.
Intensive care unit staff nurses: predicting factors for career decisions
Authors: Lai Hui‐Ling , Lin Ya‐Ping , Chang Hui‐Kuan , Wang Shu‐Chen , Liu Yun‐Ling , Lee Huei‐Chen , Peng Tai‐Chu , Chang Fwu‐Mei
Published: April 2008

Aims and Objectives.  The aim of this study was to understand the factors related to intention to leave their job among intensive care unit (ICU) nurses in eastern Taiwan and to make between‐group comparisons between an intention to leave and an intention to stay as well as to predict the influencing factors that affect ICU staff nurses’ intention to leave.

Background.  Nurses’ intention to leave their job may have an important impact on the actual turnover of nurses. The issue has always been of concern to nursing executives. Only limited empirical studies in the area have been investigated in an Asian culture context and particularly the eastern Taiwan region.

Methods.  A cross‐sectional predictive study was performed during 2005 with 130 nurses recruited from two ICUs at a medical centre. A researcher‐designed questionnaire based on the Cooper's model with structured interviews was used to determine each nurse's characteristics and their intention to leave their job. Multiple logistic regression analysis was employed to investigate the various factors associated with this.

Results.  The overall response rate was 100%; 63 (48·9%) revealed that they intended to leave their jobs. The findings were that their self‐rated health status, the number of diseases, the level of happiness, the presence of depression, job satisfaction, sleep quality, type of license and their unit were significantly associated with an intention to leave (p = 0·05–0·001). Depression and sleep quality proved to be the most significant predictors of ICU staff nurses’ intention to leave their job.

Conclusions.  The findings suggest that there is a need to take steps to improve nurses’ health‐related quality of life and to develop effective strategies to improve nurse retention.

Relevance to clinical practice.  A succinct validated instrument would help identify the important factors that predict ICU nurses’ intention to leave their job, which may result in job disengagement. Predictors found in this study may be used as outcome variables for developing such an effective method of improving nurse retention in ICUs.
The global, ppGpp‐mediated stringent response to amino acid starvation in Escherichia coli
Authors: Traxler Matthew F. , Summers Sean M. , Nguyen Huyen‐Tran , Zacharia Vineetha M. , Hightower G. Aaron , Smith Joel T. , Conway Tyrrell
Published: April 2008

The stringent response to amino acid starvation, whereby stable RNA synthesis is curtailed in favour of transcription of amino acid biosynthetic genes, is controlled by the alarmone ppGpp. To elucidate the extent of gene expression effected by ppGpp, we designed an experimental system based on starvation for isoleucine, which could be applied to both wild‐type Escherichia coli and the multiauxotrophic relA spoT mutant (ppGpp0). We used microarrays to profile the response to amino acid starvation in both strains. The wild‐type response included induction of the general stress response, downregulation of genes involved in production of macromolecular structures and comprehensive restructuring of metabolic gene expression, but not induction of amino acid biosynthesis genes en masse. This restructuring of metabolism was confirmed using kinetic Biolog assays. These responses were profoundly altered in the ppGpp0 strain. Furthermore, upon isoleucine starvation, the ppGpp0 strain exhibited a larger cell size and continued growth, ultimately producing 50% more biomass than the wild‐type, despite producing a similar amount of protein. This mutant phenotype correlated with aberrant gene expression in diverse processes, including DNA replication, cell division, and fatty acid and membrane biosynthesis. We present a model that expands and functionally integrates the ppGpp‐mediated stringent response to include control of virtually all macromolecular synthesis and intermediary metabolism.
The transcription of bradyzoite genes in Toxoplasma gondii is controlled by autonomous promoter elements
Authors: Behnke Michael S. , Radke Josh B. , Smith Aaron T. , Sullivan Jr William J. , White Michael W.
Published: April 2008

Experimental evidence suggests that apicomplexan parasites possess bipartite promoters with basal and regulated cis‐elements similar to other eukaryotes. Using a dual luciferase model adapted for recombinational cloning and use in Toxoplasma gondii, we show that genomic regions flanking 16 parasite genes, which encompass examples of constitutive and tachyzoite‐ and bradyzoite‐specific genes, are able to reproduce the appropriate developmental stage expression in a transient luciferase assay. Mapping of cis‐acting elements in several bradyzoite promoters led to the identification of short sequence spans that are involved in control of bradyzoite gene expression in multiple strains and under different bradyzoite induction conditions. Promoters that regulate the heat shock protein BAG1 and a novel bradyzoite‐specific NTPase during bradyzoite development were fine mapped to a 6–8 bp resolution and these minimal cis‐elements were capable of converting a constitutive promoter to one that is induced by bradyzoite conditions. Gel‐shift experiments show that mapped cis‐elements are bound by parasite protein factors with the appropriate functional sequence specificity. These studies are the first to identify the minimal sequence elements that are required and sufficient for bradyzoite gene expression and to show that bradyzoite promoters are maintained in a ‘poised’ chromatin state throughout the intermediate host life cycle in low passage strains. Together, these data demonstrate that conventional eukaryotic promoter mechanisms work with epigenetic processes to regulate developmental gene expression during tissue cyst formation.
The identity of the transcription +1 position is crucial for changes in gene expression in response to amino acid starvation in Bacillus subtilis
Authors: Krásný Libor , Tišerová Hana , Jonák Jiří , Rejman Dominik , Šanderová Hana
Published: April 2008

We identify here a pattern in the transcription start sites (+1A or +1G) of σA‐dependent promoters of genes that are up‐/downregulated in response to amino acid starvation (stringent response) in Bacillus subtilis. Upregulated promoters initiate mostly with ATP and downregulated promoters with GTP. These promoters appear to be sensitive to changes in initiating nucleoside triphosphate concentrations. During the stringent response in B. subtilis, when ATP and GTP levels change reciprocally, the identity of the +1 position (A or G) of these promoters is a factor important in their regulation. Mutations that change the identity of position +1 (A for G and vice versa) change the response of the promoter to amino acid starvation.
Silencing the crowd: high‐throughput functional genomics inMagnaporthe oryzae
Authors: Caracuel‐Rios Zaira , Talbot Nicholas J.
Published: April 2008

A new high‐throughput RNA‐silencing system has been developed for use in the rice blast fungusMagnaporthe oryzae, allowing rapid generation of transformants in which individual genes have been silenced. Development of this system will allow large‐scale functional analysis of genes in the fungus to define the cellular processes required for plant infection and disease symptoms. Functional analysis of 37 genes predicted to be involved in calcium signalling was carried out by RNA silencing to validate the new strategy and has provided new insight into the role of calcium‐mediated signal transduction in plant pathogenic fungi.
Demonstration of strain‐specific CD8 T cell responses to Theileria annulata
Authors: MACHUGH N. D. , BURRELLS A. C. , MORRISON W. I.
Published: April 2008

The present study set out to examine the nature and specificity of the bovine CD8 T cell response at the clonal level in a group of eight animals immunized with a cloned population of Theileria annulata. The results demonstrated that immunized animals generated parasite‐specific CD8 T cells that produced IFNγ in response to parasite stimulation but had highly variable levels of cytotoxicity for parasitized cells. The study also demonstrated that these parasite‐specific CD8 T cells could be propagated and cloned in vitro from the memory T cell pool of cattle immunized with live T. annulata parasites. Within the small group of animals studied, there was evidence that responses were preferentially directed to antigens presented by an A10+ class I major histocompatibility complex (MHC) haplotype, suggesting that responses restricted by products of this haplotype may be dominant. The A10‐restricted responses showed differential recognition of different parasite isolates and clones. By using a cloned population of parasites both for immunization of the animals and for in vitro analyses of the responses, we obtained unambiguous evidence that at least a proportion of CD8 T cells restricted by one MHC haplotype were parasite strain restricted.
Selenium supplementation enhances the protective response to Toxocara canis larvae in mice
Authors: PILARCZYK B. , DOLIGALSKA M. J. , DONSKOW‐SCHMELTER K. , BALICKA‐RAMISZ A. , RAMISZ A.
Published: April 2008

The effect of oral and intraperitoneal supply of sodium selenite on the immune response to, and the course of T. canis larvae infection in mice were determined. The number of worms in the host tissue was reduced but the migratory route of larvae was not affected. Selenite (Se) supplementation influences Se retention in the liver, enhanced IL‐5 and eosinophil responses and evoked IL‐6 production in mice infected with T. canis. The enhanced protection in mice given Se intraperitoneally was associated with high levels of parasite‐specific IgE, and enhanced concentration of Th1‐related cytokines such IL‐12p70, TNF‐α and IFN‐γ. In mice given Se orally, the predominant cytokines produced were IL‐10, MCP‐1 and IL‐6 and these mice had lower protection. In conclusion, Se supplementation increases production of specific cytokines in mice infected with T. canis and increases protection against infection.
Elevated CO2 increases photosynthesis, biomass and productivity, and modifies gene expression in sugarcane
Authors: DE SOUZA AMANDA PEREIRA , GASPAR MARILIA , DA SILVA EMERSON ALVES , ULIAN EUGÊNIO CÉSAR , WACLAWOVSKY ALESSANDRO JAQUIEL , NISHIYAMA JR. MILTON YUTAKA , DOS SANTOS RENATO VICENTINI , TEIXEIRA MARCELO MENOSSI , SOUZA GLAUCIA MENDES , BUCKERIDGE MARCOS SILVEIRA
Published: April 2008

Because of the economical relevance of sugarcane and its high potential as a source of biofuel, it is important to understand how this crop will respond to the foreseen increase in atmospheric [CO2]. The effects of increased [CO2] on photosynthesis, development and carbohydrate metabolism were studied in sugarcane (Saccharum ssp.). Plants were grown at ambient (∼370 ppm) and elevated (∼720 ppm) [CO2] during 50 weeks in open‐top chambers. The plants grown under elevated CO2 showed, at the end of such period, an increase of about 30% in photosynthesis and 17% in height, and accumulated 40% more biomass in comparison with the plants grown at ambient [CO2]. These plants also had lower stomatal conductance and transpiration rates (−37 and −32%, respectively), and higher water‐use efficiency (c.a. 62%). cDNA microarray analyses revealed a differential expression of 35 genes on the leaves (14 repressed and 22 induced) by elevated CO2. The latter are mainly related to photosynthesis and development. Industrial productivity analysis showed an increase of about 29% in sucrose content. These data suggest that sugarcane crops increase productivity in higher [CO2], and that this might be related, as previously observed for maize and sorghum, to transient drought stress.
Towards global understanding of plant defence against aphids – timing and dynamics of early Arabidopsis defence responses to cabbage aphid (Brevicoryne brassicae) attack
Authors: KUŚNIERCZYK ANNA , WINGE PER , JØRSTAD TOMMY S. , TROCZYŃSKA JOANNA , ROSSITER JOHN T. , BONES ATLE M.
Published: April 2008

Insect feeding on plants causes a complex series of coordinated defence responses. Little is known, however, about the time‐dependent aspect of induced changes. Here we present a time series‐based investigation of Arabidopsis thaliana Ler subjected to attack by a specialist pest of Brassicaceae species, Brevicoryne brassicae. Transcriptome and metabolome changes were studied at 6, 12, 24 and 48 h after infestation to monitor the progress of early induced responses. The use of full‐genome oligonucleotide microarrays revealed the initiation of extensive gene expression changes already during the first 6 h of infestation. Data indicated the involvement of reactive oxygen species (ROS) and calcium in early signalling, and salicylic acid (SA) and jasmonic acid (JA) in the regulation of defence responses. Transcripts related to senescence, biosynthesis of anti‐insect proteins, indolyl glucosinolates (GS) and camalexin, as well as several uncharacterized to date WRKY transcription factors, were induced. Follow‐up studies of defence‐involved secondary metabolites revealed depositions of callose at the insects’ feeding sites, a decrease in the total level of aliphatic GS, particularly 3‐hydroxypropyl glucosinolate, and accumulation of 4‐methoxyindol‐3‐ylmethyl glucosinolate 48 h after the attack. The novel role of camalexin, induced as a part of defence against aphids, was verified in fitness experiments. Fecundity of B. brassicae was reduced on camalexin‐accumulating wild‐type (WT) plants as compared with camalexin‐deficient pad3‐1 mutants. Based on experimental data, a model of plant–aphid interactions at the early phase of infestation was proposed.
Tomato fruit ascorbic acid content is linked with monodehydroascorbate reductase activity and tolerance to chilling stress
Authors: STEVENS R. , PAGE D. , GOUBLE B. , GARCHERY C. , ZAMIR D. , CAUSSE M.
Published: April 2008

Quantitative trait loci (QTL) mapping is a step towards the identification of factors regulating traits such as fruit ascorbic acid content. A previously identified QTL controlling variations in tomato fruit ascorbic acid has been fine mapped and reveals that the QTL has a polygenic and epistatic architecture. A monodehydroascorbate reductase (MDHAR) allele is a candidate for a proportion of the increase in fruit ascorbic acid content. The MDHAR enzyme is active in different stages of fruit ripening, shows increased activity in the introgression lines containing the wild‐type (Solanum pennellii) allele, and responds to chilling injury in tomato along with the reduced/oxidized ascorbate ratio. Low temperature storage of different tomato introgression lines with all or part of the QTL for ascorbic acid and with or without the wild MDHAR allele shows that enzyme activity explains 84% of the variation in the reduced ascorbic acid levels of tomato fruit following storage at 4 °C, compared with 38% at harvest under non‐stress conditions. A role is indicated for MDHAR in the maintenance of ascorbate levels in fruit under stress conditions. Furthermore, an increased fruit MDHAR activity and a lower oxidation level of the fruit ascorbate pool are correlated with decreased loss of firmness because of chilling injury.
Polymorphisms of the TAP 1 and 2 Gene May Influence Clinical Outcome of Primary Dengue Viral Infection
Authors: Soundravally R. , Hoti S. L.
Published: April 2008

Antigen peptides are actively transported across the endoplasmic reticulum by the transporters associated with antigen presentation (TAP). TAP genes polymorphism could influence the selection process that determines which antigen peptides play a role in the pathogenesis of dengue infection. The aim of this study was to investigate the association of TAP genes polymorphism in diverse pathogenesis of dengue infection. This study included 197 dengue‐infected patients who were further categorized into 64, 23 and 11 primary dengue fever (DF), dengue hemorrhagic fever (DHF), dengue shock syndrome (DSS) cases, respectively and 26, 52, and 21 secondary DF, DHF and DSS cases, respectively as per WHO grading system. TAP1 and 2 gene polymorphisms were performed by the amplification refractory mutation system‐polymerase chain reaction (ARMS‐PCR). Analysis of TAP1 gene polymorphism demonstrated decreased frequency of Ile/Ile genotype at TAP1333 in primary DHF cases (39.1%) when compared with primary DF (64.1%, P < 0.034, OR = 0.611).The genotype frequency of Val/Val at TAP2379 locus was significantly decreased among primary DHF (43.5%) in comparison to primary DF (71.9%, P = 0.015, OR = 0.605). Significant low proportion of primary DSS were found to have TAP1637 Asp/Asp genotypes (54.5%) when compared with primary DF (70.3%, P = 0.043). Asp/Asp genotype at TAP1637 was found to reduce the risk by 0.643 times for primary DSS. There was no significant difference in the genotypes studied between primary and secondary infection and also within secondary dengue infection in all three clinical groups. This report on TAP gene polymorphisms in dengue suggested that among the primary‐infected individuals, homozygous patterns for Ile at TAP1333 Val at TAP2379 loci and Asp at TAP1637 were found to be a protective factor against development of DHF and DSS, respectively.
Molecular and genomic basis of volatile‐mediated indirect defense against insects in rice
Authors: Yuan Joshua S. , Köllner Tobias G. , Wiggins Greg , Grant Jerome , Degenhardt Jörg , Chen Feng
Published: April 2008

Rice plants fed on by fall armyworm (Spodoptera frugiperda, FAW) caterpillars emit a blend of volatiles dominated by terpenoids. These volatiles were highly attractive to females of the parasitoid Cotesia marginiventris. Microarray analysis identified 196 rice genes whose expression was significantly upregulated by FAW feeding, 18 of which encode metabolic enzymes potentially involved in volatile biosynthesis. Significant induction of expression of seven of the 11 terpene synthase (TPS) genes identified through the microarray experiments was confirmd using real‐time RT‐PCR. Enzymes encoded by three TPS genes, Os02g02930, Os08g07100 and Os08g04500, were biochemically characterized. Os02g02930 was found to encode a monoterpene synthase producing the single product S‐linalool, which is the most abundant volatile emitted from FAW‐damaged rice plants. Both Os08g07100 and Os08g04500 were found to encode sesquiterpene synthases, each producing multiple products. These three enzymes are responsible for production of the majority of the terpenes released from FAW‐damaged rice plants. In addition to TPS genes, several key genes in the upstream terpenoid pathways were also found to be upregulated by FAW feeding. This paper provides a comprehensive analysis of FAW‐induced volatiles and the corresponding volatile biosynthetic genes potentially involved in indirect defense in rice. Evolution of the genetic basis governing volatile terpenoid biosynthesis for indirect defense is discussed.