bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuropeptide Y Y1 receptor in human dental pulp cells of noncarious and carious teeth
Authors: El Karim I. A. , Lamey P.‐J. , Linden G. J. , Lundy F. T.
Published: August 2008

Aim  To determine the distribution of the NPY Y1 receptor in carious and noncarious human dental pulp tissue using immunohistochemistry. A subsidiary aim was to confirm the presence of the NPY Y1 protein product in membrane fractions of dental pulp tissue from carious and noncarious teeth using western blotting.

Methodology  Twenty two dental pulp samples were collected from carious and noncarious extracted teeth. Ten samples were processed for immunohistochemistry using a specific antibody to the NPY Y1 receptor. Twelve samples were used to obtain membrane extracts which were electrophoresed, blotted onto nitrocellulose and probed with NPY Y1 receptor antibody. Kruskal–Wallis one‐way analysis of variance was employed to test for overall statistical differences between NPY Y1 levels in noncarious, moderately carious and grossly carious teeth.

Results  Neuropeptide Y Y1 receptor immunoreactivity was detected on the walls of blood vessels in pulp tissue from noncarious teeth. In carious teeth NPY Y1 immunoreactvity was observed on nerve fibres, blood vessels and inflammatory cells. Western blotting indicated the presence and confirmed the variability of NPY Y1 receptor protein expression in solubilised membrane preparations of human dental pulp tissue from carious and noncarious teeth.

Conclusions  Neuropeptide Y Y1 is expressed in human dental pulp tissue with evidence of increased expression in carious compared with noncarious teeth, suggesting a role for NPY Y1 in modulation of caries induced pulpal inflammation.
Pre‐clinical endodontics: a survey amongst German dental schools
Authors: Sonntag D. , Bärwald R. , Hülsmann M. , Stachniss V.
Published: August 2008

Aim  To evaluate the state and level of pre‐clinical endodontic education in German dental schools and to evaluate differences with regard to intensity and extent of teaching, time devoted to teaching pre‐clinical endodontics, personnel resources in teaching and technical equipment.

Methodology  Twenty‐eight questionnaires were e‐mailed to those in charge of pre‐clinical endodontic education in German dental schools. The extent of education, the student–teacher ratio, the teaching content as well as the application of teaching materials and technologies were asked. If, after 4 weeks, no response had been received, the questionnaire was sent out by e‐mail again. In the absence of a reply, a phone call was made to the corresponding university to conduct the survey by phone.

Results  With feedback from 27 of 28 dental schools, the response rate was 96%. Pre‐clinical endodontic education at German universities varied considerably. Theory classes ranged from 5 to 30 h (13.3 h mean), practical classes from 12.5 to 60 h (45.4 h mean). The student to staff ratio varied between 9 : 1 and 30 : 1 (16 : 1 mean). Forty‐eight per cent of the universities had a specialist in endodontics or a teacher with a special interest. A dental microscope was available for pre‐clinical teaching purposes in 38% of the universities. The majority (63%) of universities taught root canal preparation with rotary nickel titanium instruments.

Conclusion  Pre‐clinical endodontic education varied considerably between German universities because of differences in programme design, staff and course content.
Glucose reactivity with filling materials as a limitation for using the glucose leakage model
Authors: Shemesh H. , Souza E. M. , Wu M.‐K. , Wesselink P. R.
Published: August 2008

Aim  To evaluate the reactivity of different endodontic materials and sealers with glucose and to asses the reliability of the glucose leakage model in measuring penetration of glucose through these materials.

Methodology  Ten uniform discs (radius 5 mm, thickness 2 mm) were made of each of the following materials: Portland cement, MTA (grey and white), sealer 26, calcium sulphate, calcium hydroxide [Ca(OH)2], AH26,Epiphany, Resilon, gutta‐percha and dentine. After storing the discs for 1 week at 37°C and humid conditions, they were immersed in 0.2 mg mL−1 glucose solution in a test tube. The concentration of glucose was evaluated using an enzymatic reaction after 1 week. Statistical analysis was performed with the anova and Dunnett tests at a significant level of P < 0.05.

Results  Portland cement, MTA, Ca(OH)2 and sealer 26 reduced the concentration in the test tube of glucose significantly after 1 week (P < 0.05). Calcium sulphate reduced the concentration of glucose, but the difference in concentrations was not significant (P = 0.054).

Conclusions  Portland cement, MTA, Ca(OH)2 and sealer 26 react with a 0.2 mg mL−1 glucose solution. Therefore, these materials should not be evaluated for sealing ability with the glucose leakage model.
Effect of root canal irrigants on cervical dentine permeability to hydrogen peroxide
Authors: Surapipongpuntr P. , Duangcharee W. , Kwangsamai S. , Ekka A.
Published: August 2008

Aim  To examine the effects of various root canal irrigants on cervical dentine permeability by monitoring the diffusion of hydrogen peroxide (H2O2).

Methodology  Sixty cervical dentine discs were prepared from human third molar teeth. After removal of enamel and cementum, the outer dentine surface was etched with 17% ethylenediamine tetraacetic acid (EDTA) for 1 min. The dentine discs were randomly assigned to five groups according to the irrigant used: A, saline solution; B, 2.5% sodium hypochlorite solution (NaOCl); C, 5% NaOCl; D, 17% EDTA and 2.5% NaOCl; E, 17% EDTA and 5% NaOCl. After irrigation on the inner dentine surface with the various solutions, the diffusion of 30% H2O2 was evaluated through each disc using a plastic‐split chamber. H2O2 was applied to the inner‐side chamber, while the outer‐side chamber was filled with de‐ionised water. After 30 min of application of H2O2, the solution in the outer‐side chamber was collected to determine the concentration of H2O2 using a spectrophotometer.

Results  The penetration of H2O2 through dentine in group E was significantly highest, followed by groups D, C, B and A respectively (one‐way anova, P < 0.05).

Conclusions  Among the irrigants used, 17% EDTA and 5% NaOCl had the greatest effect in increasing dentinal permeability to H2O2.
Influence of cyclic torsional loading on the fatigue resistance of K3 instruments
Authors: Bahia M. G. A. , Melo M. C. C. , Buono V. T. L.
Published: August 2008

Aim  To evaluate the influence of cyclic torsional loading on the flexural fatigue resistance and torsional properties of rotary NiTi instruments.

Methodology  Twelve sets of new K3 instruments, sizes 20, 25 and 30 with an 0.04 taper, and sizes 20 and 25 with an 0.06 taper, were torsion tested until rupture, to establish their mean values of maximum torque and angular deflection. Twelve new K3 instruments of each of the following dimensions, size 30, 0.04 taper and sizes 20 and 25 with 0.06 taper, were tested to failure by rotation bending in a fatigue test device. Cyclic torsional loading was performed in 20 cycles from zero angular deflection to 180° and then return to zero applied torque. After cyclic loading, the same number of instruments were tested until rupture in torsion and flexural fatigue. Data obtained were subjected to a one way analysis of variance (anova) at 95% confidence level.

Results  Cyclic torsional loading caused no significant differences in maximum torque or in maximum angular deflection of the instruments analysed, but comparative statistical analysis between measured NCF values of new and previously cycled K3 instruments showed significant differences for all tested instrument. Longitudinal cracks, that is, cracks apparently parallel to the long axis of the instruments cycled in torsion was observed.

Conclusions  Cyclic torsional loading experiments in new K3 rotary endodontic instruments showed that torsional fatigue decreased the resistance of these instruments to flexural fatigue, although it did not affect their torsional resistance.
The importance of transformational leadership style for the well‐being of employees working with older people
Authors: Nielsen Karina , Yarker Joanna , Brenner Sten‐Olof , Randall Raymond , Borg Vilhelm
Published: August 2008

Title.  The importance of transformational leadership style for the well‐being of employees working with older people.

Aim.  This paper is a report of a study to explore the relationships between transformational leadership, followers’ perceived working conditions and employee well‐being and job satisfaction.

Background.  There is some evidence that transformational leadership style is linked to employee job satisfaction and well‐being. However, it is not clear whether this is due to (i) a direct relationship between leadership and job satisfaction and well‐being outcomes or (ii) whether followers’ perceived working conditions mediate this relationship.

Methods.  A cross‐sectional design was applied to data from a questionnaire study of 447 staff caring for older people in Denmark. Data were collected in 2005. A theory‐driven model of the relationships between leadership, working conditions, job satisfaction and well‐being was tested using structural equation modelling.

Results.  The transformational leadership style was closely associated with followers’ working conditions, namely involvement, influence and meaningfulness. Involvement was associated with job satisfaction and meaningfulness was associated with well‐being. However, working conditions were closely correlated with each other, and thus the mediating mechanisms may operate through several different working conditions. A direct path between leadership behaviour and employee well‐being was also found.

Conclusion.  Considering working conditions in the absence of studying leadership behaviour (or vice versa) may reveal an incomplete picture of the impact of work and work relationships on well‐being. Work re‐design interventions focused on influence may benefit from the consideration of training managers to exert transformational leadership behaviours.
Massage for symptom relief in patients with cancer: systematic review
Authors: Wilkinson Susie , Barnes Kelly , Storey Lesley
Published: August 2008

Title.  Massage for symptom relief in patients with cancer: systematic review.

Aim.  This paper is a report of a review to assess evidence of the effectiveness of massage for patients with cancer, in terms of reducing physical or psychological symptoms, improving quality of life, or producing unwanted side effects.

Background.  Patients with cancer may use complementary therapies, including massage and aromatherapy massage. However, their use and provision by state‐financed healthcare services is controversial.

Data sources.  A systematic review was carried out, using the Cochrane principles. No meta‐analysis was appropriate. An initial comprehensive search of electronic databases search was carried out in 2003 and updated in 2006. Eligible trials were randomized controlled trials, controlled before‐and‐after (pre–post) studies and interrupted time‐series studies. Participants were adults with a diagnosis of cancer and receiving care in any healthcare setting. Interventions were limited to massage and/or aromatherapy massage carried out by a qualified therapist. Outcome measures to be included were patient‐reported levels of physical and psychological indices of symptom distress and quality of life (measured using validated assessment tools).

Findings.  In the review, 1325 papers were considered. Ten trials met the inclusion criteria and their results suggest that massage might reduce anxiety in patients with cancer in the short term and may have a beneficial effect on physical symptoms of cancer, such as pain and nausea. However, the lack of rigorous research evidence precludes drawing definitive conclusions.

Conclusion.  Further well‐designed large trials with longer follow‐up periods are needed to be able to draw firm conclusions about the efficacy and effectiveness of massage for cancer patients.
Experiencing cancer treatment decision‐making in managed care
Authors: Wenzel Jennifer , Shaha Maya
Published: August 2008

Title.  Experiencing cancer treatment decision‐making in managed care.

Aim.  This paper is a report of a study to explore women’s perceptions of and experiences with breast cancer treatment decision‐making in managed care organizations (MCOs).

Background.  Managed care organizations are the predominant form of employer‐sponsored healthcare insurance in the United States of America. These healthcare financing entities minimize cost by streamlining healthcare delivery and may impose choice restrictions. The extent of these restrictions has not previously been studied from an in‐depth patient perspective.

Method.  A qualitative descriptive approach was adopted using interviews with a purposive sample of 14 managed care enrollees diagnosed with breast cancer at all stages. The data were collected between 2003 and 2005. Data analysis involved a reflexive process of transcript reading, categorization, data reduction and interpretation.

Findings.  The findings are presented as a single theme: ‘decisional conflict in managed care’, with two distinct categories: decisions regarding (1) the MCOs and (2) treatment. MCO selection was perceived to be limited by employer constraints, cost issues or healthcare plan providers. For study participants, selecting a MCO was less difficult than issues surrounding treatment decision‐making. Women reported that their most important treatment‐related decisions surrounded diagnosis and involved selecting a treatment facility and provider. Once a satisfactory facility and provider were selected, these women preferred to defer treatment decisions to their healthcare providers.

Conclusion.  Decision interventions should be focused on assisting women with provider and treatment facility selection early in diagnosis. Our findings might also serve as a basis for policy/practice changes to address healthcare financing limitations and to expand cancer treatment‐related choices while providing desired treatment decision‐making support.
Hygiene interventions for prevention of cytomegalovirus infection among childbearing women: systematic review
Authors: Harvey Jessica , Dennis Cindy‐Lee
Published: August 2008

Title.  Hygiene interventions for prevention of cytomegalovirus infection among childbearing women: systematic review.

Aim.  This paper is a report of a systematic review to examine the effectiveness of preventive interventions to reduce congenital cytomegalovirus transmission and infection among women of childbearing age.

Background.  Congenital cytomegalovirus has been identified as the leading infectious cause of damage to the growing fetus in developed countries, including Down syndrome, fetal alcohol syndrome and spina bifida. Despite the prevalence and consequences of this infection, it has a low profile and pregnant mothers are often unaware of the risks and protective behaviours related to its transmission. Women with children in daycare and nurses working with children are particularly at risk of acquiring the virus.

Data sources.  A computerized literature search for articles up to 1 December 2007 was performed using MEDLINE (from 1950); EMBASE (from 1980) and CINAHL (from 1982).

Review methods.  Both authors independently reviewed studies that met inclusion criteria and assigned a quality rating determined by the number of validity criteria met. Differences were discussed until consensus was reached.

Findings.  Differences in hygiene behaviour changes were most statistically significant for pregnant, seronegative women. Although the methodological quality of the three included studies was not strong, seroconversion rates consistently decreased as cytomegalovirus education and support increased.

Conclusion.  Nurses can act as preventive agents for cytomegalovirus infection through education about hygiene precautions during antenatal care and through preventive measures in the workplace. The review findings suggest educational interventions in hygiene practices have the potential to be a feasible, large‐scale, primary prevention strategy.
Postoperative pain and self‐management: women’s experiences after cardiac surgery
Authors: Leegaard Marit , Nåden Dagfinn , Fagermoen May Solveig
Published: August 2008

Title.  Postoperative pain and self‐management: women’s experiences after cardiac surgery.

Aim.  This paper is a report of a study to describe women’s experiences and their self‐management of postoperative pain after elective cardiac surgery.

Background.  Cardiac surgery involves several pain‐sensitive areas, and untreated postoperative pain may lead to chronic pain. Early discharge requires increased patient participation in pain management. Women report more postoperative pain than men after cardiac surgery.

Methods.  Semi‐structured interviews were conducted in 2004–2005 with 10 women 1–2 weeks after discharge from their first elective cardiac surgery. Qualitative content analysis was used to identify recurring themes. Pain diaries were used to record postoperative pain experiences 1–2 weeks before the interviews, providing more nuances to the experiences of pain and pain management.

Findings.  Postoperative pain experiences varied from no pain to pain all the time. Worst pain intensity was recorded as moderate or more. Pain experiences depended on what women’s expectations of pain after cardiac surgery. None wanted to complain about their painful experiences. The women had needed for more individualized information about self‐management of pain, and had difficulties remembering the information they had received. Most did not want to use pain medication, or waited to do so until pain was unbearable.

Conclusion.  Patients need more individualized and gender‐specific information before early discharge from cardiac surgery to improve self‐management. More specific predischarge education on self‐management using analgesics regularly might prevent pain ratings rising to a severe level after discharge home.
Improving district nurses’ confidence and knowledge in the principles and practice of palliative care
Authors: Shipman Cathy , Burt Jenni , Ream Emma , Beynon Teresa , Richardson Alison , Addington‐Hall Julia
Published: August 2008

Title.  Improving district nurses’ confidence and knowledge in the principles and practice of palliative care.

Aim.  This paper is a report of part of an evaluation of the impact of a national palliative care education and support programme on the knowledge and confidence of members of district nursing teams.

Background.  District nursing teams are the mainstay of ‘hands on’ provision of care at home. In recognition of their central role, the English Department of Health commissioned a national palliative care education programme as postregistration education had been limited.

Methods.  The evaluation, conducted between 2002 and 2004, had a mixed methods design. In the summative component, 1280 nurses were randomly selected from eight cancer networks to receive postal questionnaires 1 year apart, before and after the educational intervention. Changes in scores were calculated and a multiple regression analysis undertaken to identify predictors of improvement in confidence in competence and knowledge. The formative component involved qualitative interviews with a sub‐sample of 39 district nurses participating in the programme.

Findings.  Nurses who responded in both years (374/32%) were included in the analysis. There was a small statistically significant increase in confidence in palliative care competency and knowledge after participation in the educational programmes. Nurses without district nursing qualifications and who had never worked in specialist palliative care had the largest improvements in scores. Qualitative data supported these findings.

Conclusion.  The findings suggest that the education programme led to improvements in self‐reported district nursing confidence in palliative care competencies and knowledge; it is likely that the baseline level of palliative care confidence in competency and knowledge has as a result been raised nationally.
Social selection and professional regulation for Master’s degrees for nurses
Authors: Drennan Jonathan , Hyde Abbey
Published: August 2008

Title.  Social selection and professional regulation for Master’s degrees for nurses.

Aim.  This paper is a report of a study to understand the perspectives of two sets of stakeholders, namely clinical nursing providers and nursing academics, on how registered nurses should be selected for Master’s degree programmes.

Background.  The proliferation of taught Master’s programmes has led to concerns about a lowering of standards. Even with the expansion of professional Master’s programmes, they remain one of the least researched areas of higher education.

Method.  The sampling strategy was a combination of convenience and snowball sampling. In‐depth interviews were conducted in 2006–07 with 15 stakeholders and data were subjected to thematic content analysis.

Findings.  There were differences in service providers’ and academics’ perceptions of access to Master’s level education for nurses. Service providers engaged in regulatory practices, as evidenced in the way in which potential candidates were judged to be suitable or not to undertake a Master’s‐level education. Academic participants, in contrast, tended to have far fewer concerns about the career plans of applicants and were more likely to invoke discourses of academic educational admission practices.

Conclusion.  The health services need highly skilled, educated workers whose abilities and knowledge make an impact on the provision of effective patient and client care. This level of education can be achieved through continuing education of the professions by taught Master’s degrees. It is imperative that an effective partnerships between clinical service providers and academics are developed to promote understanding of their respective perceptions of admission to the degree.
Reflecting peer‐support groups in the prevention of stress and burnout: randomized controlled trial
Authors: Peterson Ulla , Bergström Gunnar , Samuelsson Mats , Åsberg Marie , Nygren Åke
Published: August 2008

Title. Reflecting peer‐support groups in the prevention of stress and burnout: randomized controlled trial.

Aim. This paper is a report of a study to test the effect of participating in a reflecting peer‐support group on self‐reported health, burnout and on perceived changes in work conditions.

Background. Stress‐related conditions are one of the most common causes for long‐term sick‐leave. There is limited evidence for the effectiveness of person‐directed interventions aimed at reducing stress levels in healthcare workers. Prior research in the relationship between support and burnout show somewhat inconsistent results.

Method. A randomized controlled trial with peer‐support groups as the intervention was conducted with 660 healthcare workers scoring above the 75th percentile on the exhaustion dimension of the Oldenburg Burnout Inventory. One hundred and fifty‐one (22·9%) agreed to participate. The intervention started in 2002 with 51 participants (96·1% were women), 80 of whom constituted the control group. Potential differences in outcome measures 12 months after the intervention were compared usingancova, and data collected was completed in 2004. Qualitative content analyses were used to analyse reported experiences from group participation.

Results. Statistically significant intervention effects were found for general health, perceived quantitative demands at work, participation and development opportunities at work and in support at work. Seven categories of experiences from participating were identified: talking to others in a similar situation, knowledge, sense of belonging, self‐confidence, structure, relief of symptoms and behavioural change.

Conclusion. Peer‐support groups using a problem‐based method could be a useful and comparatively inexpensive tool in alleviating work‐related stress and burnout.
Experiences and challenges of informal caregiving for Korean immigrants
Authors: Han Hae‐Ra , Choi Yun Jung , Kim Miyong T. , Lee Jong Eun , Kim Kim B.
Published: August 2008

Title.  Experiences and challenges of informal caregiving for Korean immigrants.

Aim.  This paper is a report of a study designed to explore the caregiving experiences of Korean Americans.

Background.  Increasing numbers of older people in the Asian population place important long‐term care demands on Asian caregivers, yet minimal attention has been given to the issue of caregiving in this group. The current study attempts to fill the gap by describing Korean American caregivers’ unique caregiving experiences from their perspectives.

Method.  A qualitative research design using a focus group approach was employed to discuss caregiving experiences in a cultural context. Data were collected over an 8‐month period in 2005. Twenty‐four informants, mostly women, at varying points surrounding caregiving participated in a focus group interview. Each focus group lasted about 1 ½–2 hours. Thematic analysis was conducted by two bilingual researchers.

Findings.  Three key themes were identified: the caregiver role – competing priorities and beliefs, the extent and impact of caregiving, and the need for education and culturally‐tailored support systems. Ten subthemes were identified within the three major themes: (1) facing double challenges; (2) changing attitudes about filial piety (Hyo); (3) providing care; (4) feeling out of control; (5) going through changing family dynamics; (6) being connected vs. providing connection; (7) paying back; (8) learning by themselves; (9) recognizing differences and (10) reconsidering geriatric care systems.

Conclusion.  The caregiving experiences described by Korean American families point to the need to identify and develop more focused outreach programmes as well as more culturally appropriate support services for this rapidly increasing population.
Human and non‐human determinants of forest composition in southern Spain: evidence of shifts towards cork oak dominance as a result of management over the past century
Authors: Urbieta Itziar R. , Zavala Miguel A. , Marañón Teodoro
Published: August 2008

Aims  Both human and non‐human determinants have shaped Mediterranean forest structure over the last few millennia. The effects of recent human activities on forest composition, however, remain poorly understood. We quantified changes in forest composition during the past century in the mixed forests of Quercus suber (cork oak) and Q. canariensis (Algerian oak), and explored the effects of forest management and environmental (climate, topography) factors on forest structure at various spatial and temporal scales.

Location  Mountains north of the Strait of Gibraltar (southern Spain).

Methods  First, we quantified 20th‐century changes in species composition from a series of inventories in nine mixed forests (c. 40,000 ha), and examined them in terms of the management practices and environmental conditions. Second, we analysed present‐day Q. suber and Q. canariensis stand structure along environmental gradients at two spatial scales: (1) that of the forest landscape (c. 284 ha), combining local inventories and topographic variables and using a digital elevation model; and (2) regional (c. 87,600 km2), combining data from the Spanish Forest Inventory for the Andalusia region and estimates of climatic variables.

Results  Historical data indicate anthropogenic changes in stand composition, revealing a sharp increase in the density of cork oaks over the last century. Forest management has favoured this species (for cork production) at the expense of Q. canariensis. The impact of management is imprinted on the present‐day forest structure. The abundance of both species increases with annual mean precipitation, and they coexist above 800 mm (the minimum threshold for Q. canariensis). Quercus suber dominates in most of the stands, and species segregation in the landscape is associated with the drainage network, Q. canariensis being clearly associated with moister habitats near streams.

Main conclusions  Our study quantitatively exemplifies a recent human‐mediated shift in forest composition. As a result of forest management, the realized niche of the cork oak has been enlarged at the expense of that of Q. canariensis, providing further evidence for humans as major drivers of oak forest composition across the Mediterranean. Recent regeneration problems detected in Q. suber stands, a reduced demand for wood products, conservation policies, and climate change augur new large‐scale shifts in forest composition.
Is the spatial distribution of European beech (Fagus sylvaticaL.) limited by its potential height growth?
Authors: Seynave Ingrid , Gégout Jean‐Claude , Hervé Jean‐Christophe , Dhôte Jean‐François
Published: August 2008

Aim To improve our understanding of species range limits by studying how height growth, a trait related to plant survival, varies throughout the geographic range ofFagus sylvaticaL. in France.

Location The geographic range of beech in France, representing the western area of its European distribution, within which this species exhibits range distribution limits in both plains and mountainous areas.

Methods A generalized linear regression model was used to link beech growth performance to environmental variables using data from 819 plots of the French National Forest Inventory (IFN) database. This model was applied to predict potential growth on 97,281 IFN plots covering the geographic range of beech in France. A kriging technique was used to interpolate estimated growth potential. Finally, the performance of plot‐based predictions of potential growth from the map (i.e. map quality) was evaluated against an independent data set.

Results The beech growth performance model highlighted the major impact of climate on potential tree growth at a broad spatial scale. The relevant climatic factors were related mainly to spring cold, summer heat, and winter temperatures and rainfall. The study also revealed the predictive power of soil parameters, which explained a large proportion of the variation in potential beech growth (c.30%). Analyses of height growth patterns near the boundary of the species range in France showed that the limit only partly coincides with the growth decline caused by climatic and soil factors. Along parts of the range limit, the predicted potential for growth was high, suggesting that in these areas the limit of the range could be explained by other factors, such as competition or constraints on reproduction.

Main conclusions The spatial variation in the potential height growth ofFagus sylvaticacan be explained by environmental factors and is partly correlated with its regional range limits. By identifying areas where growth potential constrains the geographic range of species, environmental growth models can help to improve our knowledge of the spatial drivers of species geographic range limits and shed light on their response to future environmental changes.
Cytogeography of Solidago gigantea (Asteraceae) and its invasive ploidy level
Authors: Schlaepfer Daniel R. , Edwards Peter J. , Semple John C. , Billeter Regula
Published: August 2008

Aim  Newly formed polyploids experience problems of establishment and spread similar to those faced by newly introduced alien species. To understand the significance of polyploidy in biological invasions, we mapped the distribution of ploidy levels in Solidago gigantea Aiton in its native range in North America, and in Europe and East Asia where it is invasive.

Location  North America, Europe and East Asia.

Methods  Flow cytometry was used to measure ploidy levels in a total of 834 plants from 149 locations. Together with data from contributors and a literature review, ploidy‐level data were assembled for 336 locations. Cytogeographical maps from North America and Europe were prepared, incorporating new and previously published ploidy‐level data.

Results  In the native range, diploid, tetraploid and hexaploid plants were found, and also one triploid and one pentaploid plant (2n = 3x and 2n = 5x, respectively, each being new reports for this species). There was a high degree of geographical separation among the ploidy levels, and populations with mixed ploidy were rare. However, four zones were identified where plants of different ploidy could come into contact. In Europe and East Asia, only tetraploid plants were found.

Main conclusions  The geographical pattern in North America suggests that the ploidy levels are ecologically differentiated, although further investigations are needed to identify the nature of these differences. Alien populations appear to be exclusively tetraploid, but it is not clear whether this is because tetraploids were selectively introduced or because diploids were unsuccessful. In any case, comparisons between native and introduced populations need to account for ploidy level.
Phylogeographic structure and regional history of Lemniscomys striatus (Rodentia: Muridae) in tropical Africa
Authors: Nicolas Violaine , Mboumba Jean‐François , Verheyen Erik , Denys Christiane , Lecompte Emilie , Olayemi Ayodeji , Missoup Alain D. , Katuala Pionus , Colyn Marc
Published: August 2008

Aim  This study aims to elucidate the phylogeography of the murid rodent Lemniscomys striatus and to evaluate the relative roles of ecological change, habitat patchiness, rivers and geological barriers in structuring patterns of diversity.

Location  Sub‐Saharan Africa.

Methods  The extent of phylogeographic patterns and molecular genetic diversity (cytochrome b gene) were addressed in a survey of 128 individuals of L. striatus from 42 localities. Using maximum parsimony, maximum likelihood, Bayesian, network and genetic structure analyses, we inferred intraspecific relationships and tested hypotheses for historical patterns of gene flow within L. striatus.

Results  Our results identified four major geographical clades within L. striatus: a West African clade, a Benin‐Nigeria clade, a Central African clade, and an East African clade. Several subclades were identified within these four major clades. Restricted gene flow with isolation by distance was recorded, which is congruent with the low dispersal ability of such a small murid rodent. No clear signal of population expansion was detected within clades or subclades.

Main conclusions  The western rift system and the Volta and Niger rivers may have acted as long‐term extrinsic barriers to gene flow, resulting in the emergence of the four main clades of L. striatus. The observed pattern of mitochondrial variation observed within each clade probably results from late Pleistocene climatic and vegetation changes: during adverse conditions (forest expansion), L. striatus may have survived only in refugia, and then experienced range expansion under favourable conditions (savanna expansion).
Explanations for bird species range size: ecological correlates and phylogenetic effects in the Canary Islands
Authors: Carrascal Luis M. , Seoane Javier , Palomino David , Polo Vicente
Published: August 2008

Aim To explore the determinants of island occupancy of 48 terrestrial bird species in an oceanic archipelago, accounting for ecological components while controlling for phylogenetic effects.

Location The seven main islands of the Canary archipelago.

Methods We obtained field data on population density, habitat breadth and landscape distribution in Tenerife, Fuerteventura and La Palma, aiming to sample all available habitats and the gradient of altitudes. In total, 1715 line transects of 0.5 km were carried out during the breeding season. We also reviewed the literature for data on occupancy, the distance between the Canary Islands and the nearest distribution border on the mainland, body size and endemicity of the 48 terrestrial bird species studied. Phylogenetic eigenvector regression was used to quantify (and to control for) the amount of phylogenetic signal.

Results The two measurements of occupancy (number of occupied islands or 10 × 10 km UTM squares) were tightly correlated and produced very similar results. The occupancy of the terrestrial birds of the Canary Islands during the breeding season had a very low phylogenetic effect. Species with broader habitat breadth, stronger preferences for urban environments, smaller body size, and a lower degree of endemicity had a broader geographical distribution in the archipelago, occupying a larger number of islands and 10 × 10 UTM squares.

Main conclusions The habitat‐generalist species with a tolerance for novel urban environments tend to be present on more islands and to occupy a greater area, whereas large‐sized species that are genetically differentiated within the islands are less widespread. Therefore, some properties of the ranges of these species are explicable from basic biological features. A positive relationship of range size with local abundance, previously shown in continental studies, was not found, probably because it relies on free dispersal on continuous landmasses, which may not be applicable on oceanic islands.
Ecological niche modelling of montane mammals in the Great Basin, North America: examining past and present connectivity of species across basins and ranges
Authors: Waltari Eric , Guralnick Robert P.
Published: August 2008

Aim  The goal of this study was to determine the extent of suitable habitats across the basins and ranges of the Great Basin for 13 montane mammals in the present and during the Last Glacial Maximum (LGM). For all these mammal species, we test whether: (1) more suitable habitat was available in basin areas during the LGM; (2) suitable habitat shifted upwards in elevation between the LGM and the present; (3) more ranges have suitable habitat than are currently occupied; and (4) these species are currently restricted to suitable habitats at higher‐elevation range areas. We also examine whether and how much distributional response varies among these montane mammal species.

Location  The Great Basin of western North America.

Methods  We re‐examine the past and present distributions of 13 Great Basin montane mammals using ecological niche modelling techniques that utilize now widely available species occurrence data and new, fine‐scale past climatological GIS layers in the present and at the LGM. These methods provide an objective, repeatable means for visual comparison of past and present modelled distributions for species examined in previous biogeographical studies.

Results  Our results indicate greater areal and lower elevational suitable habitat in the LGM than at present for nearly all montane mammals, and that there is more suitable habitat at present than is currently occupied. Our results also show that lowland areas provide suitable dispersal routes between ranges for most of the montane mammals both at the LGM and at present. However, three of the 13 species have little to no predicted suitable habitat in the LGM near currently occupied ranges, in contrast to the pattern for the other 10. For these species, the model results support more recent long‐distance colonization.

Main conclusions  Our finding of suitable lowland dispersal routes in the present for most species supports and greatly extends similar findings from single‐species studies. Our results also provide a visually striking confirmation that changes in species distribution and colonization histories of Great Basin montane mammals vary in a fashion related to the tolerances and requirements of each of these species; this has previously been hypothesized but not rigorously tested for multiple montane mammals in the region.
Earlywood vessel size of oak as a potential proxy for spring precipitation in mesic sites
Authors: Fonti Patrick , García‐González Ignacio
Published: August 2008

Aim  In this study, we evaluate the importance of the mean earlywood vessel size of oaks as a potential proxy for climate in mesic areas.

Location  The study was conducted in Switzerland at three forest sites dominated by oak (Quercus petraea and Q. pubescens). The three sites were in different climatic zones, varying mainly in terms of precipitation regime.

Methods  Three 50‐year‐long site chronologies of mean earlywood vessel size and tree‐ring widths were obtained at each site and related to monthly meteorological records in order to identify the main variables controlling growth. The responses of mean vessel size to climate were compared with those of the width variables to evaluate the potential climatic information recorded by the earlywood vessels.

Results  The results show that the mean vessel size has a different and stronger response to climate than ring‐width variables, although its common signal and year‐to‐year variability are lower. This response is better in particular at mesic sites, where it is linked to precipitation during spring, i.e. at the time of vessel formation, and is probably related to the occurrence of only a few processes controlling vessel growth, whereas radial increment is controlled by multiple and varying factors.

Main conclusions  The mean earlywood vessel size of oak appears to be a promising proxy for future climate reconstructions of mesic sites, where radial growth is not controlled by a single limiting factor.
Spatial aspects of trait homogenization within the German flora
Authors: Winter Marten , Kühn Ingolf , Nentwig Wolfgang , Klotz Stefan
Published: August 2008

Aim  Biotic homogenization, the replacement of local biota by non‐indigenous and locally expanding species, is among the major effects of species invasions. Almost all studies related to this topic are focused on the species level, on taxonomic homogenization. Homogenization effects on trait diversity (functional homogenization) may be very important for ecosystem functioning, but they are rarely analysed, especially not at different spatial scales within a single study. This paper aims to examine how the presence of alien species (species introduced since 1500 ad) affects the distribution of ploidy levels in the German flora at different spatial scales.

Location  Germany.

Methods  We used a resampling method and the Morisita–Horn dissimilarity index to calculate dissimilarities of ploidy level within and between alien and indigenous plants at three different spatial scales in Germany: (1) the entire country as one location, (2) between grid cells, and (3) within grid cells of a lattice covering Germany.

Results  We found a significant differentiation effect within grid cells of c. 130 km2, with alien plants increasing the variability of ploidy levels. The differentiation effect varies according to the scale used. At the coarsest scale (entire Germany), ploidy levels of alien plants tend to be more homogeneous in composition compared with those of native plants. At the intermediate scale (between grid cells), and even more pronounced at a small scale (within grid cells), ploidy levels are more heterogeneously distributed across Germany than those of native plant species.

Main conclusions  Homogenization of ploidy levels at a large scale (entire Germany) and differentiation at a small scale (within grid cells) is comparable with the patterns found in taxonomic homogenization analyses. This analysis is a first step towards understanding the impacts of plant invasions on a trait level. Differentiation and homogenization of ploidy levels might mirror the distribution of related ecological traits and therefore might have an impact on ecosystem functioning.
Global gene expression mediated by Thermus thermophilus SdrP, a CRP/FNR family transcriptional regulator
Authors: Agari Yoshihiro , Kashihara Aiko , Yokoyama Shigeyuki , Kuramitsu Seiki , Shinkai Akeo
Published: August 2008

Thermus thermophilus SdrP is one of four cyclic AMP receptor protein (CRP)/fumarate and nitrate reduction regulator (FNR) family proteins from the extremely thermophilic bacterium T. thermophilus HB8. Expression of sdrP mRNA increased in the stationary phase during cultivation at 70°C. Although the sdrP gene was non‐essential, an sdrP‐deficient strain showed growth defects, particularly when grown in a synthetic medium, and increased sensitivity to disulphide stress. The expression of several genes was altered in the sdrP disruptant. Among them, we found eight SdrP‐dependent promoters using in vitro transcription assays. A predicted SdrP binding site similar to that recognized by Escherichia coli CRP was found upstream of each SdrP‐dependent promoter. In the wild‐type strain, expression of these eight genes tended to increase upon entry into the stationary phase. Transcriptional activation in vitro was independent of any added effector molecule. The hypothesis that apo‐SdrP is the active form of the protein was supported by the observation that the three‐dimensional structure of apo‐SdrP is similar to that of the DNA‐binding form of E. coli CRP. Based on the properties of the SdrP‐regulated genes found in this study, it is speculated that SdrP is involved in nutrient and energy supply, redox control, and polyadenylation of mRNA.
Developmentally regulated sphingolipid synthesis in African trypanosomes
Authors: Sutterwala Shaheen S. , Hsu Fong‐Fu , Sevova Elitza S. , Schwartz Kevin J. , Zhang Kai , Key Phillip , Turk John , Beverley Stephen M. , Bangs James D.
Published: August 2008

Sphingolipids are essential components of eukaryotic membranes, and many unicellular eukaryotes, including kinetoplastid protozoa, are thought to synthesize exclusively inositol phosphorylceramide (IPC). Here we characterize sphingolipids from Trypanosoma brucei, and a trypanosome sphingolipid synthase gene family (TbSLS1–4) that is orthologous to Leishmania IPC synthase. Procyclic trypanosomes contain IPC, but also sphingomyelin, while surprisingly bloodstream‐stage parasites contain sphingomyelin and ethanolamine phosphorylceramide (EPC), but no detectable IPC. In vivo fluorescent ceramide labelling confirmed stage‐specific biosynthesis of both sphingomyelin and IPC. Expression of TbSLS4 in Leishmania resulted in production of sphingomyelin and EPC suggesting that the TbSLS gene family has bi‐functional synthase activity. RNAi silencing of TbSLS1–4 in bloodstream trypanosomes led to rapid growth arrest and eventual cell death. Ceramide levels were increased more than threefold by silencing suggesting a toxic downstream effect mediated by this potent intracellular messenger. Topology predictions support a revised six‐transmembrane domain model for the kinetoplastid sphingolipid synthases consistent with the proposed mammalian sphingomyelin synthase structure. This work reveals novel diversity and regulation in sphingolipid metabolism in this important group of human parasites.
The Histoplasma capsulatum vacuolar ATPase is required for iron homeostasis, intracellular replication in macrophages and virulence in a murine model of histoplasmosis
Authors: Hilty Jeremy , Smulian A. George , Newman Simon L.
Published: August 2008

Histoplasma capsulatum is a dimorphic fungal pathogen that survives and replicates within macrophages (Mφ). To identify specific genes required for intracellular survival, we utilized Agrobacterium tumefaciens‐mediated mutagenesis, and screened for H. capsulatum insertional mutants that were unable to survive in human Mφ. One colony was identified that had an insertion within VMA1, the catalytic subunit A of the vacuolar ATPase (V‐ATPase). The vma1 mutant (vma1::HPH) grew normally on iron‐replete medium, but not on iron‐deficient media. On iron‐deficient medium, the growth of the vma1 mutant was restored in the presence of wild‐type (WT) H. capsulatum yeasts, or the hydroxamate siderophore, rhodotorulic acid. However, the inability to replicate within Mφ was only partially restored by the addition of exogenous iron. The vma1::HPH mutant also did not grow as a mold at 28°C. Complementation of the mutant (vma/VMA1) restored its ability to replicate in Mφ, grow on iron‐poor medium and grow as a mold at 28°C. The vma1::HPH mutant was avirulent in a mouse model of histoplasmosis, whereas the vma1/VMA1 strain was as pathogenic as WT yeasts. These studies demonstrate the importance of V‐ATPase function in the pathogenicity of H. capsulatum, in iron homeostasis and in fungal dimorphism.