bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteomic Analysis of Somatic Embryogenesis in Medicago truncatula. Explant Cultures Grown under 6-Benzylaminopurine and 1-Naphthaleneacetic Acid Treatments
Authors: Imin Nijat , Nizamidin Mahira , Daniher Daniel , Nolan Kim E. , Rose Ray J. , Rolfe Barry G. 
Published: March 2005

Abstract
The Medicago truncatula line 2HA has a 500-fold greater capacity to regenerate plants in culture by somatic embryogenesis than wild-type Jemalong. We have compared proteomes of tissue cultures from leaf explants of these two lines. Both 2HA and Jemalong explants were grown on media containing the auxin 1-naphthaleneacetic acid and the cytokinin 6-benzylaminopurine. Proteins were extracted from the cultures at different time points (2, 5, and 8 weeks), separated by two-dimensional gel electrophoresis, and detected by silver staining. More than 2,000 proteins could be reproducibly resolved and detected on each gel. Statistical analysis showed that 54 protein spots were significantly (P &lt; 0.05) changed in expression (accumulation) during the 8 weeks of culture, and most of these spots were extracted from colloidal Coomassie-stained two-dimensional gel electrophoresis gels and were subjected to matrix-assisted laser desorption ionization time-of-flight mass spectrometry or liquid chromatography-tandem mass spectrometry analysis. Using a publicly available expressed sequence tag database and the Mascot search engine, we were able to identify 16 differentially expressed proteins. More than 60% of the differentially expressed protein spots had very different patterns of gene expression between 2HA and Jemalong during the 8 weeks of culture.
A Mitogen-Activated Protein Kinase Cascade Regulating Infection-Related Morphogenesis in Magnaporthe grisea
Authors: Zhao Xinhua , Kim Yangseon , Park Gyungsoon , Xu Jin-Rong 
Published: March 2005

Abstract
Many fungal pathogens invade plants by means of specialized infection structures called appressoria. In the rice (Oryza sativa) blast fungus Magnaporthe grisea, the pathogenicity mitogen-activated protein (MAP) kinase1 (PMK1) kinase is essential for appressorium formation and invasive growth. In this study, we functionally characterized the MST7 and MST11 genes of M. grisea that are homologous with the yeast MAP kinase kinase STE7 and MAP kinase kinase kinase STE11. Similar to the pmk1 mutant, the mst7 and mst11 deletion mutants were nonpathogenic and failed to form appressoria. When a dominant MST7 allele with S212D and T216E mutations was introduced into the mst7 or mst11 mutant, appressorium formation was restored in the resulting transformants. PMK1 phosphorylation also was detected in the vegetative hyphae and appressoria of transformants expressing the MST7 S212D T216E allele. However, appressoria formed by these transformants failed to penetrate and infect rice leaves, indicating that constitutively active MST7 only partially rescued the defects of the mst7 and mst11 mutants. The intracellular cAMP level was reduced in transformants expressing the MST7 S212D T216E allele. We also generated MST11 mutant alleles with the sterile alpha motif (SAM) and Ras-association (RA) domains deleted. Phenotype characterizations of the resulting transformants indicate that the SAM domain but not the RA domain is essential for the function of MST11. These data indicate that MST11, MST7, and PMK1 function as a MAP kinase cascade regulating infection-related morphogenesis in M. grisea. Although no direct interaction was detected between PMK1 and MST7 or MST11 in yeast two-hybrid assays, a homolog of yeast STE50 in M. grisea directly interacted with both MST7 and MST11 and may function as the adaptor protein for the MST11-MST7-PMK1 cascade.
Timing of the Maternal-to-Zygotic Transition during Early Seed Development in Maize
Authors: Grimanelli Daniel , Perotti Enrico , Ramirez Jorge , Leblanc Olivier 
Published: March 2005

AbstractIn animals, early embryonic development is largely dependent on maternal transcripts synthesized during gametogenesis. Recent data in plants also suggest maternal control over early seed development, but the actual timing of zygotic genome activation is unclear. Here, we analyzed the timing of the maternal-to-zygotic transition during early Zea mays seed development. We show that for 16 genes expressed during early seed development, only maternally inherited alleles are detected during 3 d after fertilization in both the embryo and the endosperm. Microarray analyses of precocious embryonic development in apomictic hybrids between maize and its wild relative, Tripsacum, demonstrate that early embryo development occurs without significant quantitative changes to the transcript population in the ovule before fertilization. Precocious embryo development is also correlated with a higher proportion of polyadenylated mRNA in the ovules. Our data suggest that the maternal-to-zygotic transition occurs several days after fertilization. By contrast, novel transcription accompanies early endosperm development, indicating that different mechanisms are involved in the initiation of endosperm and embryo development.
Novel Functions of Plant Cyclin-Dependent Kinase Inhibitors, ICK1/KRP1, Can Act Non-Cell-Autonomously and Inhibit Entry into Mitosis
Authors: Weinl Christina , Marquardt Sebastian , Kuijt Suzanne J.H. , Nowack Moritz K. , Jakoby Marc J. , Hülskamp Martin , Schnittger Arp 
Published: March 2005

AbstractIn animals, cyclin-dependent kinase inhibitors (CKIs) are important regulators of cell cycle progression. Recently, putative CKIs were also identified in plants, and in previous studies, Arabidopsis thaliana plants misexpressing CKIs were found to have reduced endoreplication levels and decreased numbers of cells consistent with a function of CKIs in blocking the G1-S cell cycle transition. Here, we demonstrate that at least one inhibitor from Arabidopsis, ICK1/KRP1, can also block entry into mitosis but allows S-phase progression causing endoreplication. Our data suggest that plant CKIs act in a concentration-dependent manner and have an important function in cell proliferation as well as in cell cycle exit and in turning from a mitotic to an endoreplicating cell cycle mode. Endoreplication is usually associated with terminal differentiation; we observed, however, that cell fate specification proceeded independently from ICK1/KRP1-induced endoreplication. Strikingly, we found that endoreplicated cells were able to reenter mitosis, emphasizing the high degree of flexibility of plant cells during development. Moreover, we show that in contrast with animal CDK inhibitors, ICK1/KRP1 can move between cells. On the one hand, this challenges plant cell cycle control with keeping CKIs locally controlled, and on the other hand this provides a possibility of linking cell cycle control in single cells with the supracellular organization of a tissue or an organ.
A Mechanism of Nonphotochemical Energy Dissipation, Independent from PsbS, Revealed by a Conformational Change in the Antenna Protein CP26
Authors: Dall'Osto Luca , Caffarri Stefano , Bassi Roberto 
Published: March 2005

AbstractThe regulation of light harvesting in higher plant photosynthesis, defined as stress-dependent modulation of the ratio of energy transfer to the reaction centers versus heat dissipation, was studied by means of carotenoid biosynthesis mutants and recombinant light harvesting complexes (LHCs) with modified chromophore binding. The npq2 mutant of Arabidopsis thaliana, blocked in the biosynthesis of violaxanthin and thus accumulating zeaxanthin, was shown to have a lower fluorescence yield of chlorophyll in vivo and, correspondingly, a higher level of energy dissipation, with respect to the wild-type strain and npq1 mutant, the latter of which is incapable of zeaxanthin accumulation. Experiments on purified thylakoid membranes from all three mutants showed that the major source of the difference between the npq2 and wild-type preparations was a change in pigment to protein interactions, which can explain the lower chlorophyll fluorescence yield in the npq2 samples. Analysis of the xanthophyll binding LHC proteins showed that the Lhcb5 photosystem II subunit (also called CP26) undergoes a change in its pI upon binding of zeaxanthin. The same effect was observed in wild-type CP26 upon treatment that leads to the accumulation of zeaxanthin in the membrane and was interpreted as the consequence of a conformational change. This hypothesis was confirmed by the analysis of two recombinant proteins obtained by overexpression of the Lhcb5 apoprotein in Escherichia coli and reconstitution in vitro with either violaxanthin or zeaxanthin. The V and Z containing pigment-protein complexes obtained by this procedure showed different pIs and high and low fluorescence yields, respectively. These results confirm that LHC proteins exist in multiple conformations, an idea suggested by previous spectroscopic measurements (Moya et al., 2001), and imply that the switch between the different LHC protein conformations is activated by the binding of zeaxanthin to the allosteric site L2. The results suggest that the quenching process induced by the accumulation of zeaxanthin contributes to qI, a component of NPQ whose origin was previously poorly understood.
A Novel Plant Cysteine Protease Has a Dual Function as a Regulator of 1-Aminocyclopropane-1-Carboxylic Acid Synthase Gene Expression
Authors: Matarasso Noa , Schuster Silvia , Avni Adi 
Published: March 2005

Abstract
The hormone ethylene influences plant growth, development, and some defense responses. The fungal elicitor Ethylene-Inducing Xylanase (EIX) elicits ethylene biosynthesis in tomato (Lycopersicon esculentum) and tobacco (Nicotiana tabacum) leaves by induction of 1-aminocyclopropane-1-caboxylic acid synthase (Acs) gene expression. A minimal promoter element in the LeAcs2 gene required for EIX responsiveness was defined by deletion analysis in transgenic tomato plants. The sequence between −715 and −675 of the tomato Acs2 gene was found to be essential for induction by EIX. A Cys protease (LeCp) was isolated that specifically binds to this cis element in vitro. Ectopic expression of LeCp in tomato leaves induced the expression of Acs2. Moreover, chromatin immunoprecipitation showed that LeCp binds in vivo to the Acs promoter. We propose a mechanism for the dual function of the LeCp protein. The protease acts enzymatically in the cytoplasm. Then, upon signaling, a small ubiquitin-related modifier protein binds to it, enabling entrance into the nucleus, where it acts as a transcription factor. Thus, LeCp can be considered a dual-function protein, having enzymatic activity and, upon elicitor signaling, exhibiting transcriptional factor activity that induces LeAcs2 expression.
Preference structure for cheese consumers
Authors: Tendero Antonio , Bernabéu Rodolfo 
Published: March 2005

PurposeThe purpose of this paper is to contribute to knowledge on the preferences of cheese consumers in Spain. The first step was to determine where and how frequently cheeses are purchased and consumed, along with different aspects relating to the recognition of cheeses certified by a denomination of origin (DO). The second step consisted in determining how consumer preferences are structured.Design/methodology/approachThe methodology consisted of a survey of 412 consumers in the Castilla‐La Mancha Region who were buying food items for their homes. In order to process data related to the first step, a descriptive analysis was undertaken. For the second step, a conjoint analysis was carried out, with three types of attributes (price, certification and type).FindingsThe results show that cheese is a food which is present and also consumed within Spanish homes, while being bought in supermarkets at least once a week. Consumers value most the DO labels as a guarantee of quality and food safety. The cheese that is best known to consumers is the Manchego DO. Consumers prefer cheeses which are well‐priced, aged and, if possible, certified.Originality/valueThis paper analyses current consumer behaviour and, by means of conjoint analysis, identifies consumer preferences for cheeses in Spain. Internationally, conjoint analysis has rarely been used for cheeses, and this would appear to be the first time it has been applied in Spain.
Notions of region and the Mediterranean diet in food advertising
Authors: Cannon Jackie 
Published: March 2005

PurposeThe paper aims to review the perceived benefits of the Mediterranean diet alongside traditional or regional foodstuffs, and to examine the extent to which food producers and retailers make use of these labels in order to enhance the perceived value of their products.Design/methodology/approachThe paper draws on marketing literature relating to origin cues within the food industry. It first analyses criteria used by the EU for food labelling, following this with a review of the perceived value of authenticity in foodstuffs, offering an evaluation of Mediterranean‐labelled products available from a leading UK supermarket chain.FindingsThe paper involves an exploration into the descriptors used by food producers, suggesting they are designed to respond to consumers’ subjective criteria in food choices with only tenuous links to the promoted origins and corresponding quality designations. It is concluded that regional and Mediterranean labels do not display common dietary or preparation features but are convenient marketing labels designed to enhance food product attributes.Originality/valueIt appears that regional links or the term “Mediterranean”, when linked to foodstuffs, suggest a level of authenticity that is not always borne out in product ingredients and preparation methods. Origin and authenticity are widely held to enhance the perceived attributes of food products but this paper highlights certain mismatches between regional quality marks and food marketing practices. Greater awareness of the practices employed to satisfy “subjective criteria” when making food choices is of benefit to consumers.
Agro‐biotechnology and organic food purchase in the United Kingdom
Authors: Rimal Arbindra P. , Moon Wanki , Balasubramanian Siva 
Published: March 2005

PurposeThe objective of this paper is to evaluate the role of consumers’ perceived risks and benefits of agro‐biotechnology in shaping the purchase pattern for organic food among UK consumers.Design/methodology/approachAn on‐line household survey of UK consumers was conducted using household panels maintained by the National Panel Diary (NPD) group. The data included organic food purchase pattern, perceived risks and benefits of agro‐biotechnology, and socio‐demographic information about the respondents. A regression model was used to examine the impact of consumers’ general purchase behavior, perceived risks and benefits of GM technology, and socio‐demographic on organic food purchase.FindingsOnly 4 percent of the respondents purchased organic foods all the time, while 26 percent never purchased. Perceived risks of agro‐biotechnology played a dominant role in influencing organic food purchase decisions. As the risk perception increased consumers were likely to buy organic food more often. Although premium prices of organic foods were of concern to many consumers, food safety was the most important consideration when making organic food purchase decisions. Household income positively influenced consumers’ likelihood of buying organic food. Female respondents were likely to purchase organic foods more often than their male counter parts. Older respondents were less likely to buy organic foods compared to younger respondents.Practical implicationsThe results of this study provide valuable information in formulating short and long‐term marketing programs for organic producers. Following the study results, food safety concern and perceived risks of GM food products need to be the overall theme of marketing programs for organic products.Originality/valueThe study uses a large sample size in examining the relationship between perceived risks of agro‐biotechnology and organic food purchase. The results are more robust and representative.
Valorization of traditional foods
Authors: Di Monaco Rossella , Di Marzo Sabrina , Cavella Silvana , Masi Paolo 
Published: March 2005

PurposeThis study aimed to assess if an Italian artisanal pasta filata cheese, named Provolone del Monaco, is perceived by consumers as typical or not and if any variability exists among cheeses made by different dairies.Design/methodology/approachTwo experiments were performed. In the first experiment, two artisanal Provolone del Monaco having different ripening times and two industrial Provolone cheeses were evaluated. A total of 95 subjects, divided into three homogeneous groups, first rated the samples in blind condition, then, after having received information about typicality; price, and both sets of information. In the second experiment, the quantitative descriptive profiles of eight Provolone del Monaco samples aged six months and made by different dairies were compared with the quantitative descriptive profiles of the same cheese aged ten months and provolone cheeses made by industrial dairies.FindingsConsumer results revealed that consumers knowing typicality information gave a better score to cheeses markedly different. The price together with typicality information, represented a quality indicator. Cluster analysis of descriptive scores revealed homogeneity between the equally aged Provolone del Monaco samples. Moreover descriptive data showed that cheese was characterized by several specific attributes, that the consumer, probably, recognized as typical.Research limitationsIt must be noticed that once it was performed in Campania, the results extrapolation to other regions or countries should not be made unless similar results are found.Originality/valueThis study will contribute to better addressing consumer needs and enhancing the competitiveness of traditional foods.
Tribological design of hydrodynamic sliding journal bearings – formulating new functional charts
Authors: Pandazaras C. , Petropoulos G. 
Published: March 2005

PurposeThis paper aims to introduce an innovative methodology for the determination of operational characteristics of journal bearings (j‐bs) through using new type charts based upon a numerical solution of the Reynolds equation.Design/methodology/approachThe present paper proposes the mapping of the behaviour of a smooth, isothermal and hydrodynamic (j‐b) as a first step towards a future representation of the behaviour of j‐b's with limited length and high lubricating clearance with or without macro or micro topographic features operating under high loads, high temperatures and low linear velocities leading to conditions of mixed or boundary lubrication.FindingsThe derived analytical relationships between dimensionless quantities lead to the development of high precision synthetic operational charts regarding sliding j‐b of any given geometry and varying operational characteristics.Originality/valueBy considering the iso‐operational curves which are of a hook form relevant to comparative data becomes directly and rapidly clarified.
On the squeeze film lubrication of long porous journal bearings with couple stress fluids
Authors: Naduvinamani N.B. , Hiremath P.S. , Tasneem Fathima Syeda 
Published: March 2005

PurposeThis paper aims to advance the squeeze film characteristics of long partial journal bearings with couple stress fluid studied by Lin to include the effect of permeability on the squeeze film lubrication of long partial porous journal bearings with couple stress fluids.Design/methodology/approachA semi‐analytical and semi‐numerical solution for the squeeze film lubrication of long porous partial journal bearings lubricated with couple stress fluid is presented in the paper. The modified Reynolds equation governing the fluid film pressure is derived. The modified Reynolds equation is solved analytically and closed form expressions for the squeeze film pressure and load carrying capacity are presented. The first‐order non‐linear equation for the time‐height relation is solved numerically with the given initial condition. The effect of couple stresses and permeability on the squeeze film characteristics are discussed.FindingsIt is found that the effect of couple stresses is to increase the load carrying capacity and to lengthen the squeeze film time as compared to the corresponding Newtonian case. The effect of permeability is to reduce the load carrying capacity and to decrease the squeeze film time as compared to the corresponding solid case.Originality/valueIn the design of porous partial journal bearings, the reduction in the load carrying capacity and the response time can be compensated by the use of lubricants with proper microstructures by which the bearing life can be increased.
The analysis of the effects of surface texture on the capability of load carriage of journal bearings using neural network
Authors: Si˙nanoğlu Cem 
Published: March 2005

PurposeThis paper investigates the load carrying capacity of the journal bearings with steel shafts with varying surface texture in varying revolutions using experimental and neural network (NN) approach.Design/methodology/approachIn this study, we used a shaft with smooth surface with the same material properties compare their load carrying capacities of the shafts with three different pitches and two different profiles. The experimental data, such as pressure and oil temperature, are employed as training and testing data for NN. Quick Prop algorithm is used to update the weight of the network during the training.FindingsThe designated NN has superior performance for modelling of the system. Therefore, the proposed neural predictor would be used as a predictor for possible experimental applications on modelling bearing system.Research limitations/implicationsMobil 0W‐40 lubricant was used and kept at temperature of 18°C. The surface of the shafts has been in two types: smooth, that is without and with profiles, that is trapezoidal and saw.Practical implicationsOwing to the parallel structure and fast learning of NN, this kind of algorithm will be utilized to model other types of bearing systems.Originality/valueInstead of traditional methods, NN has fast learning and parallel processing structure. Moreover, NN can be used to process multiple‐input/multiple‐output data unlike other empirical modelling tools which can map one dependent variable at a time. Therefore, this method is able to predict the load carrying capacity with steel shafts with varying surface texture in varying revolutions satisfactorily where common techniques have failed.
The relationship between work commitment models and employee withdrawal intentions
Authors: Carmeli Abraham , Gefen David 
Published: March 2005

PurposeThis study is an attempt to contribute to an emerging stream of research, which attempts to explore how work commitment forms affect one another and how together they serve to influence work behaviour and outcomes.Design/methodology/approach– Drawing on five universal forms of work commitment, we tested the relationships between two work commitment models and two forms of employee withdrawal intentions: from their organisation and from their occupation. To this end, we investigated professional employees (social workers) employed in the Israeli healthcare system through a structured questionnaire.Findings– Path analysis results cast doubt on the applicability of both models in their original form, across scenarios. At the same time, with some modifications, both models show a good potential for explaining variance in employee withdrawal intentions from both their organisation and their occupation.Originality/value– This research contributes to work commitment literature by providing empirical findings and theoretical interpretations regarding the role of a particular professional setting in explaining the interrelationships among models of work commitment, and how some constellations of different work commitment foci explain multiple withdrawal intentions.