bluuebunny/crossref_metadata_2025 huggingface dataset:
The candidate gene approach: have murine models informed the study of human SLE?
Authors: CUNNINGHAME GRAHAM D S , VYSE T J
Published: June 2004

Genome wide linkage studies in human SLE have identified seven highly significant loci linked to SLE, and more than 20 other loci showing suggestive linkage to disease. However, pin-pointing the susceptibility alleles in candidate genes within these linkage regions is challenging, due the genetic heterogeneity, racial differences and environmental influences on disease aetiology. Utilization of murine models of spontaneous lupus nephritis provide a complementary approach, which may then identify candidate genes for analysis in human cases. This review highlights the utility of cross-species approach to identify and characterize the effect of given candidate genes in lupus. The examples described in this review demonstrate the importance of bringing together both genetic and functional information in human and mouse studies.
Nutritional quality of biofilms with respect to light regime in Lake Saint‐Pierre (Québec, Canada)
Authors: Huggins Kim , Frenette Jean‐Jacques , Arts Michael T.
Published: June 2004

1.In situexperiments were conducted using specialised incubation devices to grow biofilms under varying light regimes and grazing intensities (by excluding fish and large‐sized zooplankton, >2 mm) both within and between two sites in Lake Saint‐Pierre.

2. Biofilms growing under greaterin situUVR and light exposures found in the south water mass were characterised by a greater biomass and nutrient content, but their total fatty acid (FA) contents and ratios of elemental nutrients were not significantly different from the north. There was a relatively greater abundance of chlorophytes and cyanobacteria in the south water mass, along with a greater proportion of low nutritional quality saturated fatty acids (SAFA). Conversely, biofilms growing in the north had a greater relative abundance of diatoms, as well as greater eicosapentaneoic acid (20:5ω3) and docosahexaneoic acid (22:6ω3) concentrations (two FAs implicated in the physiological competency of grazers).

3. The prevailing community structures created differences in terms of nutritional status of the biofilms for benthic grazers and their predators at the two sites. The biofilms from the southern site were characterised by greater food quantity at the expense of quality, while biofilms from the northern site contained less food of a better quality. Despite this, the nutritional regime in the south supported a greater productivity at higher trophic levels. The secondary treatments (light and grazing by fish and macro‐invertebrates) had lesser effects on food quality.
Nurse Competence Scale: development and psychometric testing
Authors: Meretoja Riitta , Isoaho Hannu , Leino‐Kilpi Helena
Published: June 2004

Background.  Self‐assessment assists nurses to maintain and improve their practice by identifying their strengths and areas that may need to be further developed. Professional competence profiles encourage them to take an active part in the learning process of continuing education. Although competence recognition offers a way to motivate practising nurses to produce quality care, few measuring tools are available for this purpose.

Aim.  This paper describes the development and testing of the Nurse Competence Scale, an instrument with which the level of nurse competence can be assessed in different hospital work environments.

Methods.  The categories of the Nurse Competence Scale were derived from Benner's From Novice to Expert competency framework. A seven‐step approach, including literature review and six expert groups, was used to identify and validate the indicators of nurse competence. After a pilot test, psychometric testing of the Nurse Competence Scale (content, construct and concurrent validity, and internal consistency) was undertaken with 498 nurses. The 73‐item scale consists of seven categories, with responses on a visual analogy scale format. The frequency of using competencies was additionally tested with a four‐point scale.

Results.  Self‐assessed overall scores indicated a high level of competence across categories. The Nurse Competence Scale data were normally distributed. The higher the frequency of using competencies, the higher was the self‐assessed level of competence. Age and length of work experience had a positive but not very strong correlation with level of competence. According to the item analysis, the categories of the Nurse Competence Scale showed good internal consistency.

Conclusion.  The results provide strong evidence of the reliability and validity of the Nurse Competence Scale.
Knowledge acquisition, synthesis, and validation: a model for decision support systems
Authors: O'Neill Eileen S. , Dluhy Nancy M. , Fortier Paul J. , Michel Howard E.
Published: June 2004

Background. Decision tools such as clinical decision support systems must be built on a solid foundation of nursing knowledge. However, current methods to determine the best evidence do not include a broad range of knowledge sources. As clinical decision support systems will be designed to assist nurses when making critical decisions, methods need to be devised to glean the best possible knowledge.

Aims. This paper presents a comprehensive knowledge development process to develop a nursing clinical decision support system.

Discussion. The Nurse Computer Decision Support Project (N‐CODES) is developing a prototype for a prospective decision support system. The prototype is being constructed on rules and cases generated by the best available evidence. To accommodate the range of decisions made in practice, different types of evidence are necessary. The process incorporates procedures to uncover, evaluate, and assimilate information to develop the knowledge domain for a clinical decision support systems. Both formal and practice‐based knowledge are included. The model contains several innovative approaches including the use of clinical experts and a network of practicing clinicians.

Conclusion. These strategies will assist scientists and practitioners interested in determining the best evidence to support clinical decision support systems.
Nurse practitioner education: a research‐based curriculum structure
Authors: Gardner Glenn , Gardner Anne , Proctor Margaret
Published: June 2004

Background.  The process and content of nurse practitioner educational preparation has received scant research attention, despite increasing interest in and investigations into nurse practitioner services in Australia and internationally.

Aims.  The aim of this paper is to report a study investigating the educational process and content required for nurse practitioner preparation.

Methods.  A trial of practice was conducted with four nurse practitioner candidates over a 12‐month period. The candidates practised in different specialities, giving rise to four models of the nurse practitioner role. The trial had multiple aims related to the role and scope of practice of the nurse practitioner. An action learning model was used, in which participating nurse practitioner candidates ‘worked‐into‐the‐role’ of extended practice and learned from experience through clinical mentoring, reflection and action. Data collection methods centred on transcripts from group work activities related to a collaborative engagement with and reflections on clinical practice. This resulted in the collaborative production of data to inform a research‐based nurse practitioner curriculum structure.

Findings.  The findings relate to the content and learning process required for nurse practitioner education and are described in terms of three broad areas of study: clinical practice, clinical sciences and nursing studies.

Conclusions.  A curriculum structure that describes content and process for nurse practitioner education was developed from the findings. A further outcome of this trial was confirmation of importance of the clinical environment for nurse practitioner education. Inherent in this aspect of clinical learning is the role of a committed clinical mentor who can facilitate purposeful learning.
Developing Lecturer Practitioner roles using action research
Authors: Williamson Graham R. , Webb Christine , Abelson‐Mitchell Nadine
Published: June 2004

Background.  Lecturer Practitioner roles are well established in the United Kingdom. The national literature demonstrates that these staff are valuable to National Health Service trusts and universities however, their roles are busy and demanding, with conflicting expectations from the two employers. In addition, their role in addressing the theory–practice gap – a major reason for their establishment – is at best unclear. Although a number of qualitative studies have explored the topic, there have been no systematic attempts to develop the role or to quantify the effects on postholders.

Aim.  This paper reports a study that aimed to develop aspects of Lecturer Practitioners’ work roles, examine the effects of this on individuals at one English university, and to quantify Lecturer Practitioners’ occupational stress and burnout.

Methods.  A flexible, ‘spiral’ action research framework and ‘collaborative group approach’ were used, with mixed methods of data collection. Data were collected through focus groups, meetings and participant feedback, and participants’ reflective diaries. A questionnaire using previously validated psychological attitude rating scales was also used to measure occupational stress and burnout, the extent to which the project influenced these, and the influence of Lecturer Practitioners’ experience and qualifications. Six null hypotheses were constructed to measure these ideas. Findings from qualitative and quantitative perspectives were triangulated to give depth to the analysis.

Findings.  Five themes emerged from the focus groups: personal motivation, workload pressures, role clarity, preparation and support, and gains from the role. Specific policies and documentation were developed as a result of this initial project planning work. The findings from the questionnaire indicated that Lecturer Practitioners were no more stressed or burnt out than comparable workers. Synthesis of findings indicated, broadly speaking, that these LPs were ‘thriving rather than just surviving’.

Conclusion.  Action research was an effective methodology for uncovering new knowledge, and bringing about organizational change in this project.
Parents’ experiences of having a child with cleft lip and palate
Authors: Johansson Barbro , Ringsberg Karin C.
Published: June 2004

Background.  Giving birth to a child with cleft lip and palate (CLP) can be emotionally traumatic for parents. The facial appearance awakens feelings and reactions in the family and other people. Feeding these children in the neonatal period is known to be difficult. Previous research has mainly dealt with visual defects, feeding and speech problems. There is a lack of studies about parents’ experiences of having a child with CLP.

Aims.  This study was performed to investigate parents’ experiences of having a child born with a cleft lip or CLP, and how they perceive encouragement and social and mental support from professionals, family and friends.

Method.  A phenomenographic approach was used. The study was performed at a university hospital in central Sweden. Twenty families (20 mothers and 12 fathers) were interviewed using guided interviews.

Findings.  Two categories, consisting of three and two subcategories, emerged. Informants described their experiences of having a child with CLP, how they slowly adapted to this situation, the first meeting with their child, support from professionals, and reactions from family and other people. Parents commented on the craniofacial team with satisfaction. Due to a low level of knowledge, other professionals often had difficulty in handling the situation and a poor quality of advice on feeding was reported. Family and friends commented on the child positively or by being neutral, which was seen as a lack of interest. A visible scar on the face was seen as a problem, especially for girls. Most informants expressed anxiety about possible problems with speech.

Conclusions.  Parents did not look upon their child as handicapped but as having a congenital defect or ‘flaw’. The findings of this study could be used in staff education to promote understanding of parents’ experiences and how best to help them. They could also be used in the general media to improve public understanding. Future research could explore staff perceptions of this sensitive clinical area.
Personal understandings of illness among people with type 2 diabetes
Authors: Hörnsten Åsa , Sandström H. , Lundman B.
Published: June 2004

Background.  Professionals and patients understand the experience of illness from different worlds. Professionals’ explanatory models focus on aetiology, diagnosis, pathophysiology and treatment, while patients’ explanatory models are more focused on consequences and influences on daily life. The differences between patients and professionals in their understanding often result in conflicting expectations about treatment, priorities and outcomes of care.

Aim.  The aim of this study was to describe personal understandings of illness among people with type 2 diabetes in Sweden.

Method.  A sample of 44 patients, 47–80 years, diagnosed with type 2 diabetes within the last 2 years, was recruited from four health care centres. Narrative thematic interviews were used covering the areas of developing, coping with and living with diabetes. Qualitative content analysis was performed.

Findings.  The findings were formulated into six categories: image of the disease, meaning of the diagnosis, integration of the illness, space for the illness, responsibility for care and future prospects.

Conclusions.  The findings demonstrate that patients’ personal understanding of illness is an important complement to the traditional professional view of diabetes. They could serve as a foundation for development of health history interviewing, as well as development of systems of documentation. Patients’ personal understandings of diabetes in their daily lives are considered to be an important shared source of information for planning meaningful care.
Utilization of research findings by graduate nurses and midwives
Authors: Veeramah V.
Published: June 2004

Background.  There is mounting pressure on nurses and midwives in the United Kingdom to use research findings to inform their practice. However, many still find research difficult to understand and are poorly prepared by education to make use of it. Hence, there is a pressing need to evaluate the research education included in nursing and midwifery curricula.

Aim.  This paper reports a study assessing the impact of research education on the attitudes towards research and use of research findings in practice by graduate nurses and midwives.

Method.  A cross‐sectional survey using a self‐completed postal questionnaire was conducted with a sample of 340 nurse and midwife graduates in the South East of England.

Findings.  A response rate of 51% was obtained. A large number of respondents stated that their critical appraisal (96%) and search skills (87%) had improved following graduation and they reported using research findings in practice (16·8% all the time, 50·5% frequently and 32·6% sometimes). Furthermore, the majority expressed positive attitudes towards research and these were related to the research education received. However, a significant number reported finding statistics difficult to understand, lack of time to read research and limited access to research findings at their place of work. Also, a number of respondents would still like more help with searching the literature, implementing research findings in practice and developing their critical appraisal skills further.

Conclusion.  It is crucial that some of the major barriers to research utilization are addressed at both individual and organizational levels if evidence‐based care is to become a reality. Also, health service managers should consider a number of strategies suggested by respondents to increase the use of research findings in clinical settings.
Postdischarge nursing interventions for stroke survivors and their families
Authors: McBride Kelly L. , White Carole L. , Sourial Rosa , Mayo Nancy
Published: June 2004

Background.The physical, cognitive, and emotional sequelae of stroke underscore the need for nursing interventions across the continuum of care. Although there are several published studies evaluating community interventions for stroke survivors, the nursing role has not been clearly articulated.

Aim.The aim of this paper is to report a study to describe, using a standardized classification system, the nursing interventions used with stroke survivors during the initial 6 weeks following discharge home.

Methods.In the context of a randomized controlled trial, two nurse case managers provided care to 90 community‐dwelling stroke survivors who were assigned to the intervention arm of the trial. The nursing documentation was analysed, using the Nursing Intervention Classification (NIC) system, to identify and quantify the interventions that were provided.

Findings.Stroke survivors received, on average, six different interventions. There was a trend for those who were older, more impaired, and who lived alone to receive more interventions. The most commonly reported interventions included those directed towards ensuring continuity of care between acute and community care, family care, and modifying stroke risk factors. The study was limited to the nursing documentation, which may represent an underestimation of the care delivered.

Conclusions.The NIC system was useful in capturing the interventions delivered by the nurse case managers. Nursing interventions are often not clearly articulated and less often use standardized terminology. Describing nursing activities in a standard manner will contribute to an increase in nursing knowledge and to evidence‐based practice.
Nurses’ use of online clinical evidence
Authors: Gosling A. Sophie , Westbrook Johanna I. , Spencer Rosemary
Published: June 2004

Background.  The ‘information explosion’ presents a significant challenge to the nursing profession. One way to assist access to information is to provide electronic information resources at the point of care. A large‐scale survey of nurses working in the public health system in New South Wales, Australia, was undertaken as part of a 2‐year evaluation of the Clinical Information Access Program (CIAP). This is a website which provides 24 hour, online access to a range of evidence sources at the point of care.

Aim.  This paper reports a study to investigate factors influencing nurses’ use of online evidence available at the point of care and to examine differences between nurses in different roles.

Method.  Nurses from 65 randomly selected hospitals were surveyed. A convenience sample representing 25% of nursing staff at these hospitals was sought. Eighty‐four per cent of the survey quota was met and 3128 questionnaires were completed and returned.

Results.  The results showed that 58% of nurses had heard of the CIAP and, of those, 70% had used the website's resources. Senior nurses had greater awareness and use than others. The most frequent reasons for use were to fill a knowledge gap and for personal education. Lack of training was the most frequently cited reason for not using the website. Use of online evidence, particularly amongst senior staff, was higher than reported in previous studies.

Conclusion.  Use of online evidence was associated with nursing role, and with managerial and organizational support. Diffusion of innovation theory can help to explain some of the patterns observed. The use and impact of online evidence should be interpreted in the context of nursing practice and culture.
Characteristics of falls in hospitalized patients
Authors: Kerzman Hana , Chetrit Angela , Brin Luna , Toren Orly
Published: June 2004

Background.  The high incidence of patient falls in a hospital setting is a major concern in any health system. Research findings have reported the risk factors for these falls as age, gender, certain medications, mental status, chronic diseases and environmental factors. Falls may lead to fear, pain, slight or severe injuries, increase the duration of hospital stay, cause patient discomfort and affect quality of life.

Aim.  The aim of this paper is to report a study of the characteristics of patient falls during hospitalization in 1998 and compare them with those in the period 1978–1981.

Methods.  A retrospective study was performed in a large, 2000‐bed medical center in Israel. Reports of 711 fall incidents in 1998 were compared with 328 reports in 1978–1981. Information gathered included age, gender, department, shift, reasons, severity of injury, tests and treatment after injury.

Results.  The rates of falls per 1000 admissions in psychiatric, elder care and rehabilitation departments in 1998 were statistically significantly higher than in the earlier period. Rates of 115, 91, 85, respectively, per 1000 admissions were reported in 1998 compared with 34, 9, 19, respectively, in the period 1978–1981. The percentage of reported falls in the younger age group (under 50) was higher in the later survey (1998), and a higher proportion occurred outside the patient's room. Most of the reported falls in 1998 occurred during the morning shift (P < 0·001).

Conclusions.  The increased number of falls could be an outcome of increased awareness. Nevertheless, the causes and place of falls differ for the two periods. Some of the reasons may be related to an intervention programme carried out after the first survey. The latest survey results will serve as an important basis for a further intervention programme in specific departments to ensure patient safety.
Interdisciplinary preoperative patient education in cardiac surgery
Authors: Tromp Fred , van Dulmen Sandra , van Weert Julia
Published: June 2004

Background.  In 1998, we carried out a study of interdisciplinary preoperative education in cardiac surgery given by nurses, physicians and health educators. Overlaps were found in gathering and providing information by physicians, nurses and health educators, and gaps were found in providing psychosocial information and emotional support. Based on these findings, an information protocol was developed.

Aim.  This paper reports a study examining the effects of the implementation of the information protocol on the content and process of preoperative education.

Methods.  Dialogues between health educators and patients were videotaped at the preoperative clinic (n = 54) and on the day of admission (n = 53), and analysed using a checklist of 123 specific topics.

Results.  The information given by health educators at the outpatient clinic and on the day of admission accorded with the information protocol to a large extent. There was also an increase in the number of psychosocial issues raised. Nurses raised significantly more psychosocial issues in comparison with before implementation of the protocol. After implementation, patients spent approximately 3 minutes less talking with the health educator and about 7 minutes less talking with a nurse. This suggests that on the day of admission a more time‐efficient co‐ordination in patient education was achieved.

Conclusions.  Implementation of the information protocol led to a better interdisciplinary division of labour. The education is tailored more to the needs of the patient, and psychosocial items are mentioned more frequently. This straightforward intervention gave very positive results. Inconsistencies, gaps and overlaps in information provision can be avoided by the unambiguous delineation of responsibilities and tasks in information provision by different health care providers.
Assessment of gastric accommodation: overview and evaluation of current methods
Authors: De Schepper H. U. , Cremonini F. , Chitkara D. , Camilleri M.
Published: June 2004

Abstract Gastric accommodation is considered important in the pathophysiology of several upper gastrointestinal disorders including functional dyspepsia. The gold standard for its measurement is the barostat‐balloon study which requires intubation. The aim was explore the reliability and performance characteristics of the techniques proposed for measurement of gastric accommodation. We undertook a literature search using MEDLINE with a broad range of key words. The accommodation reflex and its control are briefly described, based on human data. The performance characteristics of the intragastric barostat, transabdominal ultrasound, magnetic resonance imaging, single photon emission computed tomography, and satiation drinking tests are described. For each technique, we summarize the following: principle, validation studies, advantages, disadvantages, and potential applications. Three‐dimensional methods to measure gastric volume non‐invasively are promising and among the best validated to date. Simpler techniques would be of considerable appeal for clinical and research studies, but further validation is necessary before satiation drinking tests can be used as surrogates for more sophisticated measurements of gastric accommodation.
Presynaptic modulation of cholinergic and non‐cholinergic fast synaptic transmission in the myenteric plexus of guinea pig ileum
Authors: LePard K. J. , Ren J. , Galligan J. J.
Published: June 2004

Abstract  These studies investigated receptors modulating release of mediators of fast excitatory postsynaptic potentials (fEPSPs) in guinea pig ileum myenteric plexus using electrophysiological methods. Fast EPSPs inhibited by >95% by hexamethonium (100 μmol L−1) were cholinergic; mixed fEPSPs were inhibited <95% by hexamethonium. Non‐cholinergic fEPSPs were studied in the presence of hexamethonium. The α2‐adrenergic receptor agonist UK 14304 inhibited cholinergic (maximum inhibition = 76%, EC50 = 18 nmol L−1), mixed (81%, 21 nmol L−1) and non‐cholinergic (76%, 44 nmol L−1) fEPSPs equally. The 5‐HT1 receptor agonist 5‐carboxamidotryptamine inhibited cholinergic, mixed and non‐cholinergic fEPSPs equally. Renzapride, increased non‐cholinergic (33%) less than mixed (97%, 13 μmol L−1) fEPSPs. Renzapride inhibited the purely cholinergic fEPSPs (−29%) but potentiated the cholinergic component of mixed fEPSPs (39%). Prucalopride potentiated all fEPSPs equally (30–33%). 5‐HT (0.1 μmol L−1) induced potentiation of cholinergic (75%), mixed (97%) and non‐cholinergic (84%) fEPSPs was not statistically different. The potentiating effects of renzapride and 5‐HT on fEPSPs were inhibited by the 5‐HT4 receptor antagonist, SB 204070 (10 nmol L−1). Renzapride (0.3 μmol L−1) blocked 5‐HT‐induced increases in cholinergic fEPSPs. α2‐Adrenergic and 5‐HT1 receptors mediate inhibition of transmitter release from cholinergic and mixed terminals. 5‐HT and prucalopride, acting at 5‐HT4 receptors, facilitate all fEPSPs; renzapride facilitates the cholinergic and non‐cholinergic components of mixed fEPSPs but not purely cholinergic fEPSPs. Cholinergic synapses may express few 5‐HT4 receptors or a renzapride‐insensitive 5‐HT4 receptor isoform.
Presence of C‐type natriuretic peptide (CNP) in guinea pig caecum: role and mechanisms of CNP in circular smooth muscle relaxation
Authors: Itaba S. , Chijiiwa Y. , Matsuzaka H. , Motomura Y. , Nawata H.
Published: June 2004

Abstract  The distribution and role of C‐type natriuretic peptide (CNP) in the gastrointestinal tract are still unclear. This study was designed to investigate the distribution of CNP in guinea pig caecum and the inhibitory mechanisms of CNP in caecal circular smooth muscle cells. CNP immunoreactivity was recognized in smooth muscle cells, myenteric and submucosal neurons of the caecum by immunohistochemistry. CNP mRNA expression was demonstrated in both freshly dispersed and cultured smooth muscle cells by reverse‐transcription polymerase chain reaction. CNP inhibited 1 nmol L−1 cholecystokinin octapeptide (CCK‐8)‐induced smooth muscle cell contraction in a dose‐dependent manner, with an IC50 value of 0.24 nmol L−1, and significantly stimulated the production of intracellular cyclic guanosine monophosphate. Furthermore, inhibitors of both soluble and particulate guanylate cyclase (GC) partially but significantly inhibited CNP‐induced relaxation. This is the first report demonstrating that CNP localizes in gastrointestinal smooth muscle cells and the enteric nervous system. These results suggest that CNP acts locally through neural and autocrine pathways to modulate colonic motility via both particulate and soluble GC systems. These two pathways appear to be through natriuretic peptide receptor (NPR)‐B, which has particulate GC domain, and NPR‐C, which activates soluble GC, judging from previous findings that NPR‐A is not expressed in these cells.
L‐type Ca2+ channel expression along feline smooth muscle oesophagus
Authors: Muinuddin A. , Ji J. , Sheu L. , Kang Y. , Gaisano H. Y. , Diamant N. E.
Published: June 2004

Abstract  Muscle from the proximal smooth muscle (SM) oesophagus of the cat demonstrates contractions of greater amplitude and greater sensitivity to cholinergic stimulation than muscle from the distal SM oesophagus. In the light of the central role of calcium influx in SM contractility, we hypothesized that regional differences in oesophageal contractility may be associated with differential expression of L‐type calcium channels (LCa) along the SM oesophagus. LCa expression was compared between proximal and distal regions of the circular SM oesophagus by Western blots. Patch clamp technique was utilized to study LCa currents. Muscle strip studies assessed LCa contribution to contractile activity. The protein expression of LCa and LCa current density was greater in the proximal than distal region. LCa voltage and time‐dependent activation and inactivation curves were similar in cells from both regions. Stimulation of muscle strips with acetylcholine (ACh) in the presence of tetrodotoxin resulted in contractions of greater amplitude in the proximal region. The LCa agonist Bay K 8644 caused a greater increase in ACh‐induced contraction amplitude in muscle strips from the proximal region. Therefore, regional myogenic differences in LCa expression along the circular SM oesophageal body exist and may contribute to the nature of oesophageal contractions.
The expression patterns of arabinogalactan‐protein AtAGP30 and GLABRA2 reveal a role for abscisic acid in the early stages of root epidermal patterning
Authors: Van Hengel Arjon J. , Barber Chris , Roberts Keith
Published: June 2004

In the Arabidopsis root, patterning of the epidermal cell types is position‐dependent. The epidermal cell pattern arises early during root development, and can be visualized using reporter genes driven by the GLABRA (GL)2 promoter as markers. The GL2 gene is preferentially expressed in the differentiating hairless cells (atrichoblasts) during a period in which epidermal cell identity is believed to be established. We show that AtAGP30 is also expressed in atrichoblasts. This gene encodes an arabinogalactan‐protein (AGP) that is known to play a role in root regeneration and increases abscisic acid (ABA)‐response rates. Although the expression level of this gene is regulated by the plant growth factors ABA and ethylene, only ABA was found to affect the tissue‐specific pattern of expression. ABA also disrupts the expression pattern of the GL2::GUS (β‐glucuronidase) reporter gene. Our results indicate that ABA regulates epidermal cell‐type‐specific gene expression in the meristematic zone of the Arabidopsis root, while ethylene is known to act at later stages of epidermal differentiation. Despite its effects on the early stages of root epidermal patterning, ABA does not affect root hair formation on mature wild‐type epidermal cells, suggesting that other developmental cues, like positional information, can progressively over‐ride the ABA‐mediated disruption of early epidermal patterning.
Catalase deficiency drastically affects gene expression induced by high light in Arabidopsis thaliana
Authors: Vandenabeele Steven , Vanderauwera Sandy , Vuylsteke Marnik , Rombauts Stephane , Langebartels Christian , Seidlitz Harald K. , Zabeau Marc , Van Montagu Marc , Inzé Dirk , Van Breusegem Frank
Published: June 2004

In plants, hydrogen peroxide (H2O2) plays a major signaling role in triggering both a defense response and cell death. Increased cellular H2O2 levels and subsequent redox imbalances are managed at the production and scavenging levels. Because catalases are the major H2O2 scavengers that remove the bulk of cellular H2O2, altering their levels allows in planta modulation of H2O2 concentrations. Reduced peroxisomal catalase activity increased sensitivity toward both ozone and photorespiratory H2O2‐induced cell death in transgenic catalase‐deficient Arabidopsis thaliana. These plants were used as a model system to build a comprehensive inventory of transcriptomic variations, which were triggered by photorespiratory H2O2 induced by high‐light (HL) irradiance. In addition to an H2O2‐dependent and ‐independent type of transcriptional response during light stress, microarray analysis on both control and transgenic catalase‐deficient plants, exposed to 0, 3, 8, and 23 h of HL, revealed several specific regulatory patterns of gene expression. Thus, photorespiratory H2O2 has a direct impact on transcriptional programs in plants.
Expression analysis suggests novel roles for the plastidic phosphate transporter Pht2;1 in auto‐ and heterotrophic tissues in potato and Arabidopsis
Authors: Rausch Christine , Zimmermann Philip , Amrhein Nikolaus , Bucher Marcel
Published: June 2004

A cDNA encoding Pht2;1 from potato, a new member of the plant Pht2 gene family of low‐affinity orthophosphate (Pi) transporters, was isolated. The expression pattern of the corresponding gene as well as its ortholog from Arabidopsis was analyzed and the encoded proteins were localized in the two plants. Pht2;1 expression is strongly upregulated by light in potato and Arabidopsis leaf tissue. RNA gel blot analysis, reverse transcription‐polymerase chain reaction (RT‐PCR), promoter/GUS, and protein/green fluorescent protein (GFP) fusion studies, respectively, indicate that the gene is expressed in both auto‐ and heterotrophic tissues and its encoded protein is localized to the plastids. The similar patterns of Pht2;1 gene regulation in potato and Arabidopsis prompted us to screen publicly available gene expression data from 228 Arabidopsis oligonucleotide microarrays covering 83 different experimental conditions. Modulation of Pht2;1 transcript levels was overall moderate, except for a limited number of experimental conditions where Pht2;1 mRNA concentrations varied between 2‐ and 3.7‐fold. Overall, these analyses suggest involvement of the Pht2;1 protein in cell wall metabolism in young, rapidly growing tissues, independent of other Pi transporters such as the high‐affinity Solanum tuberosum Pi transporter 1 (StPT1). Cluster analysis allowed identification of colinear or antiparallel expression profiles of a small set of genes involved in post‐translational regulation, and photosynthetic carbon metabolism. These data give clues about the possible biological function of Pht2;1 and shed light on the complex web of interactions in which Pht2;1 could play a role.
Mutual antagonism of ethylene and jasmonic acid regulates ozone‐induced spreading cell death in Arabidopsis
Authors: Tuominen Hannele , Overmyer Kirk , Keinänen Markku , Kollist Hannes , Kangasjärvi Jaakko
Published: June 2004

Ethylene (ET) and jasmonic acid (JA) have opposite effects on ozone (O3)‐induced spreading cell death; ET stimulates, and is required for the spreading cell death, whereas JA protects tissues. We studied the underlying molecular mechanisms with the O3‐sensitive, JA‐insensitive jasmonate resistant 1 (jar1), and the O3‐tolerant, ET‐insensitive ethylene insensitive 2 (ein2) mutants. Blocking ET perception pharmacologically with norbornadiene (NBD) in jar1, or ET signaling genetically in the jar1 ein2 double mutant prevented the spread of cell death. This suggests that EIN2 function is epistatic to JAR1, and that the JAR1‐dependent JA pathway halts oxidative cell death by directly inhibiting ET signaling. JAR1‐dependent suppression of the ET pathway was apparent also as increased EIN2‐dependent gene expression and ET hypersensitivity of jar1. Physiological experiments suggested that the target of JA is upstream of Constitutive Triple Response 1 (CTR1), but downstream of ET biosynthesis. Gene expression analysis of 1‐aminocyclopropane‐1‐carboxylic acid (ACC)‐treated and O3‐exposed ein2 and jar1 revealed reciprocal antagonism: the EIN2‐mediated suppression of the JA pathway. The results imply that the O3‐induced spreading cell death is stimulated by early, rapid accumulation of ET, which can suppress the protecting function of JA thereby allowing cell death to proceed. Extended spreading cell death induces late accumulation of JA, which inhibits the propagation of cell death through inhibition of the ET pathway.
Metabolic engineering of monoterpene biosynthesis: two‐step production of (+)‐trans‐isopiperitenol by tobacco
Authors: Lücker Joost , Schwab Wilfried , Franssen Maurice C. R. , Van Der Plas Linus H. W. , Bouwmeester Harro J. , Verhoeven Harrie A.
Published: June 2004

Monoterpenoid biosynthesis in tobacco was modified by introducing two subsequent enzymatic activities targeted to different cell compartments. A limonene‐3‐hydroxylase (lim3h) cDNA was isolated from Mentha spicata L. ‘Crispa’. This cDNA was used to re‐transform a transgenic Nicotiana tabacum‘Petit Havana’ SR1 (tobacco) line expressing three Citrus limon L. Burm. f. (lemon) monoterpene synthases producing (+)‐limonene, γ‐terpinene and (−)‐β‐pinene as their main products. The targeting sequences of these synthases indicate that they are probably localized in the plastids, whereas the sequence information of the P450 hydroxylase indicates targeting to the endoplasmatic reticulum. Despite the different location of the enzymes, the introduced P450 hydroxylase proved to be functional in the transgenic plants as it hydroxylated (+)‐limonene, resulting in the emission of (+)‐trans‐isopiperitenol. Some further modifications of the (+)‐trans‐isopiperitenol were also detected, resulting in the additional emission of 1,3,8‐p‐menthatriene, 1,5,8‐p‐menthatriene, p‐cymene and isopiperitenone.
Single‐point mutations at the surface of MB‐1Trp lead to important changes in its conformational properties
Authors: Sasseville M. , Claveau S. , Gagnon M.C. , Beauregard M.
Published: June 2004

Abstract:  Protein design is currently used for the creation of new proteins with desirable traits. In our lab we focus on the synthesis of proteins with high essential amino acid content having potential applications in animal nutrition. One of the limitations we face in this endeavour is achieving stable proteins despite a highly biased amino acid content. We report here the synthesis and the characterization of three variants of MB‐1Trp in which two solvent‐exposed Leu have been replaced by Glu allowing for the formation of new salt bridges at the surface of the protein. Although both mutations were expected to be similar (i.e. same mutation in a comparable local environment), they appear to have different effects on MB‐1Trp as shown by far‐UV circular dichroism, thermal denaturation, fluorescence and proteolytic resistance measurements. For the mutation Leu68Glu, an increase in the protein melting temperature of 6 °C was observed. Surprisingly, the mutation in position Leu19Glu led to a decrease in melting temperature and a modification of tertiary structure.
Selective targeting of a laccase from Stachybotrys chartarum covalently linked to a carotenoid‐binding peptide
Authors: Janssen G.G. , Baldwin T.M. , Winetzky D.S. , Tierney L.M. , Wang H. , Murray C.J.
Published: June 2004

Abstract:  A two‐step targeting strategy was used to identify improved laccases for bleaching carotenoid‐containing stains on fabric. We first applied a modified phage display technique to identify peptide sequences capable of binding specifically to carotenoid stains and not to fabric. Prior deselection on the support on which the carotenoid was localized, increased stringency during the biopanning target selection process, and analysis of the phage peptides’ binding to the target after acid elution and polymerase chain reaction (PCR) postacid elution, were used to isolate phage peptide libraries with increased binding selectivity and affinity. Peptide sequences were selected based on identified consensus motifs. We verified the enhanced carotenoid‐binding properties of the peptide YGYLPSR and subsequently cloned and expressed C‐terminal variants of laccase from Stachybotrys chartarum containing carotenoid‐binding peptides YGYLPSR, IERSAPATAPPP, KASAPAL, CKASAPALC, and SLLNATK. These targeted peptide–laccase fusions demonstrate enhanced catalytic properties on stained fabrics.
The 10th and 11th residues of short length N‐terminal PTH(1–12) analogue are important for its optimum potency
Authors: Lim S.‐K. , Lee E.J. , Kim H.‐Y. , Lee W.
Published: June 2004

Abstract:  The 10th and 11th residues of parathyroid hormone PTH(1–12) analogues were substituted to study the structure and function of PTH analogues. The substitution of Ala10 of [Ala3,10,12(Leu7/Phe7)Arg11]rPTH(1–12)NH2 with Glu10 and/or the Arg11 with Ile11 markedly decreased cAMP generating activity. Data from circular dichroism (CD) and the nuclear magnetic resonance (NMR) structural analysis of [Ala3,10,12(Leu7/Phe7)Arg11]rPTH(1–12)NH2 revealed tight α‐helical structures, while the Glu10 and/or Ile11 substituted analogues showed unstable α‐helical structures. We conclude that 10th and 11th residues are important for stabilizing its helical conformation and that destabilization of the α‐helical structure, induced by substituting the above residues, remarkably affect its biological potency.
Purification and characterization of a new peptide with analgesic effect from the scorpion Buthus martensi Karch
Authors: Cao Z.‐Y. , Mi Z.‐M. , Cheng G.‐F. , Shen W.‐Q. , Xiao X. , Liu X.‐M. , Liang X.‐T. , Yu D.‐Q.
Published: June 2004

Abstract:  A new peptide, designated as Buthus martensi Karch (BmK) AngM1, with an isoelectric point (pI) of 5.8 was purified and characterized from the venom of Buthus martensi Karch. The molecular mass was calculated as 7040.5 Da from multiple‐charged ions by elelctrospray ionization mass spectroscopy (ESI/MS). The complete amino acid sequence of BmK AngM1 of 64 amino acid residues was determined by automatic sequencing of N‐terminal part of the native peptide and the fragments of reduced and S‐carboxymethylated (RCM)‐peptide degraded by Staphylococcus aureaus V8 protease and TPCK(N‐p‐Tosyl‐L‐phenylalanine chloromethyl ketone)‐treated trypsin. Bioactivity tested using mouse‐twisting model showed an evident analgesic effect with 63.0% (P < 0.001) inhibition efficiency at the dose of 0.8 mg/kg, but the LD50 was larger than 50 mg/kg. Electrophysiological studies showed that BmK AngM1 at the concentration of 1 μm obviously inhibit voltage‐dependent Na+ current (INa) and voltage‐dependent delayed rectifier K+ current (IK) but had no effects on transient K+ current.
Delaying evolution of insect resistance to transgenic crops by decreasing dominance and heritability
Authors: Tabashnik B. E. , Gould F. , Carrière Y.
Published: June 2004

The refuge strategy is used widely for delaying evolution of insect resistance to transgenic crops that produce Bacillus thuringiensis (Bt) toxins. Farmers grow refuges of host plants that do not produce Bt toxins to promote survival of susceptible pests. Many modelling studies predict that refuges will delay resistance longest if alleles conferring resistance are rare, most resistant adults mate with susceptible adults, and Bt plants have sufficiently high toxin concentration to kill heterozygous progeny from such matings. In contrast, based on their model of the cotton pest Heliothis virescens, Vacher et al. (Journal of Evolutionary Biology, 16, 2003, 378) concluded that low rather than high toxin doses would delay resistance most effectively. We demonstrate here that their conclusion arises from invalid assumptions about larval concentration-mortality responses and dominance of resistance. Incorporation of bioassay data from H. virescens and another key cotton pest (Pectinophora gossypiella) into a population genetic model shows that toxin concentrations high enough to kill all or nearly all heterozygotes should delay resistance longer than lower concentrations.
Fine-scale genetic structure and gene dispersal in Centaurea corymbosa (Asteraceae) I. Pattern of pollen dispersal
Authors: Hardy O. J. , González-Martínez S. C. , Fréville H. , Boquien G. , Mignot A. , Colas B. , Olivieri I.
Published: June 2004

Pollen dispersal was characterized within a population of the narrowly endemic perennial herb, Centaurea corymbosa, using exclusion-based and likelihood-based paternity analyses carried out on microsatellite data. Data were used to fit a model of pollen dispersal and to estimate the rates of pollen flow and mutation/genotyping error, by developing a new method. Selfing was rare (1.6%). Pollen dispersed isotropically around each flowering plant following a leptokurtic distribution, with 50% of mating pairs separated by less than 11 m, but 22% by more than 40 m. Estimates of pollen flow lacked precision (0–25%), partially because mutations and/or genotyping errors (0.03–1%) could also explain the occurrence of offspring without a compatible candidate father. However, the pollen pool that fertilized these offspring was little differentiated from the adults of the population whereas strongly differentiated from the other populations, suggesting that pollen flow rate among populations was low. Our results suggest that pollen dispersal is too extended to allow differentiation by local adaptation within a population. However, among populations, gene flow might be low enough for such processes to occur.
Cheating is not always punished: killer female plants and pollination by deceit in the dwarf palm Chamaerops humilis
Authors: Dufaÿ M. , Anstett M.-C.
Published: June 2004

Because the interests of mutualists are not perfectly aligned, conflicts between partners often arise, rendering mutualism unstable by allowing the evolution of cheating. The dwarf palm Chamaerops humilis is engaged in a nursery pollination mutualism with a specific weevil Derelomus chamaeropsis. In exchange for pollen dispersal, dwarf palms provide pollinators with food, shelter and egg-laying sites, but pollinators can develop only within male inflorescences. Here we show that weevils lay eggs in female inflorescences but processes associated with fruit development prevent larval development. The cost imposed by developing larvae probably differs between male and female plants, explaining why only females defend their inflorescences. Female palms thus cheat their pollinating weevil, and pollinators are expected to ‘punish’ (avoid) them. We found no evidence for such punishment: weevils visit female plants and the duration of visits to male and female inflorescences does not differ. Thus mutualists do not always co-operate and cheating may not be necessarily punished.