bluuebunny/crossref_metadata_2025 huggingface dataset:
Early development of bioluminescence suggests camouflage by counter‐illumination in the velvet belly lantern shark Etmopterus spinax (Squaloidea: Etmopteridae)
Authors: Claes J. M. , Mallefet J.
Published: October 2008

The development of luminous structures and the acquisition of luminescence competence during the ontogeny of the velvet belly lantern shark Etmopterus spinax, a deep‐sea squalid species, were investigated. The sequential appearance of nine different luminous zones during shark embryogenesis were established, and a new terminology for them given. These zones form the complex luminous pattern observed in free‐swimming animals. The organogenesis of photophores (photogenic organs) from the different luminous zones was followed, and photophore maturation was marked by the appearance of green fluorescent vesicles inside the photocytes (photogenic cells). Peroxide‐induced light emissions as well as spontaneous luminescence analysis indicated that the ability of E. spinax to produce light was linked to the presence of these fluorescent vesicles and occured prior to birth. The size of photogenic organs, as well as the percentage of ventral body surface area occupied by the luminous pattern and covered by photophores increased sharply during embryogenesis but remained relatively stable in free‐swimming animals. All these results strongly suggest camouflage by counter‐illumination in juvenile E. spinax.
Quantitative histopathology of Oreochromis niloticus gills after copper exposure
Authors: Monteiro S. M. , Rocha E. , Fontaínhas‐Fernandes A. , Sousa M.
Published: October 2008

In order to test whether histopathological changes of gills demonstrated a good dose–response relationship with water copper levels, juvenile Nile tilapia Oreochromis niloticus, of both sexes and similar mass (36·3 + 7·7 g), were kept in dechlorinated tap water (temperature 25° C, range ±1° C; pH 6·5–7·5; hardness 74·5 mg l−1 CaCO3) and exposed to 40 and 400 μg l−1 of copper. Gill samples were collected after 3, 7, 14 and 21 days. Six major histopathological changes (oedema, lifting, changes in filament epithelium thickness, lamellar fusion, vasodilatation and aneurisms) and three minor ones (proliferation of the lamellar epithelium, necrosis and adjacent lamellar fusion) were found and their prevalence estimated. The extent and severity of each histopathological change were used to develop a severity gradation scale (SGS). Semi‐quantitative analysis of the histopathological changes and measurements of gill copper deposition levels revealed a good dose– and time–response relationship. Oedemas and aneurisms were significantly correlated with acute exposure periods and lamellar fusion with chronic exposure. Epithelial lifting and changes in filament epithelial thickness were seen at lower and higher metal concentrations, respectively. The data also revealed that the SGS profile of each lesion was dependent of gill copper burden.
Life history of a wide‐ranging deepwater lantern shark in the north‐east Atlantic, Etmopterus spinax (Chondrichthyes: Etmopteridae), with implications for conservation
Authors: Coelho R. , Erzini K.
Published: October 2008

In this paper, the population biology of the velvet belly lanternshark Etmopterus spinax was studied and life‐history coefficients determined. Age was estimated from sections of the second dorsal spine and validated by marginal increment analysis. Males attained a maximum age of 8 years while 11 year‐old females were found. Several growth models were fitted and compared for both size‐at‐age and mass‐at‐age data, showing that even though this is a small‐sized species, it has a relatively slow growth rate. This species matures late, specifically at 49·6 and 42·5% of the maximum observed ages for males and females, respectively. It has a low fecundity, with a mean ovarian fecundity of 9·94 oocytes and a mean uterine fecundity of 7·59 embryos per reproductive cycle. This species seems to have a long reproductive cycle, and even though no conclusive data were obtained, a 2–3 year cycle is possible. The estimated coefficients indicate that this species has a vulnerable life cycle, typical of deepwater squalid sharks. Given the high fishing pressures that it is suffering in the north‐east Atlantic, this fish may already be facing severe declines or in risk of facing them in the near future.
Influence of xanthine oxidase on thiopurine metabolism in Crohn’s disease
Authors: ANSARI A. , ASLAM Z. , DE SICA A. , SMITH M. , GILSHENAN K. , FAIRBANKS L. , MARINAKI A. , SANDERSON J. , DULEY J.
Published: October 2008

Background  The thiopurines, azathioprine (AZA) and mercaptopurine are extensively used in Crohn’s disease (CD). Thiopurine bioactivation can be diverted by either thiopurine methyltransferase (TPMT), or by xanthine oxidase/dehydrogenase (XOD) which forms 6‐thiouric acid (6TU).

Aim  To investigate whether chronic inflammation could influence small intestinal XOD activity using urinary excretion of 6TU as a surrogate marker of XOD activity.

Methods  6‐Thiouric acid excretion was compared between 32 CD patients and nine dermatology patients (control group), on AZA. Six CD patients were interesting: five with low TPMT activity (one deficient, four intermediate), and one receiving AZA/allopurinol co‐therapy.

Results  There was no statistical difference in 6TU excretion between the CD and control group. CD location, severity or surgery did not affect excretion. The TPMT‐deficient patient excreted 89% of daily AZA dose as 6TU, but excretion by TPMT carriers was essentially normal. Concurrent 5‐aminosalicylic acid therapy increased 6TU excretion significantly (median 32.9%), consistent with inhibiting TPMT. 6TU was undetectable in the patient on AZA/allopurinol co‐therapy.

Conclusions  The results refuted our hypothesis, but fitted a model where most of an oral thiopurine dose effectively escapes first‐pass metabolism by gut XOD, but is heavily catabolized by TPMT. Bioavailability of thiopurines may be competitively inhibited by dietary purines.
Predictors of subjective fatigue in chronic gastrointestinal disease
Authors: SIMRéN M. , SVEDLUND J. , POSSERUD I. , BJORNSSON E. S. , ABRAHAMSSON H.
Published: October 2008

Background  Fatigue is a common, but poorly understood symptom in patients with chronic gastrointestinal (GI) diseases.

Aim  To evaluate factors of importance for fatigue in patients with chronic GI diseases, and to compare it with fatigue in the general population.

Methods  In all, 399 patients attending a GI out‐patient clinic completed questionnaires assessing fatigue, sleep disturbances, psychological general well‐being and GI symptom severity. The patients were divided into two diagnostic groups: functional GI disorders (n = 112) and organic GI diseases (n = 287). The severity of fatigue was also evaluated in an age‐ and gender‐matched group of 399 individuals from the general population.

Results  Both patient groups had more severe fatigue than controls and patients with functional GI disorders were more fatigued than patients with an organic GI disease. Fatigue was associated with psychological general well‐being, GI symptom severity, gender, employment status and sleep disturbances. In a linear regression analysis, psychological general well‐being (vitality, general health, self‐control), sleep disturbances and employment status were independently associated with the severity of fatigue (adjusted R2 = 55%).

Conclusions  Fatigue is a troublesome symptom in a subgroup of patients with chronic GI diseases. These patients have a high symptom burden as regards both GI and psychological symptoms, as well as sleep disturbances.
Predictive factors associated with immunosuppressive agent use in ulcerative colitis: a case–control study
Authors: LAU A. , CHANDE N. , PONICH T. , GREGOR J. C.
Published: October 2008

Background  Some patients with ulcerative colitis (UC) require immunosuppressants as maintenance therapy.

Aim  To assess epidemiological, clinical and disease factors at diagnosis that predict immunosuppressant use in UC.

Methods  All UC patients diagnosed between 1992 and 2005 and currently managed in the inflammatory bowel disease (IBD) clinic were included. Forty‐three patients who currently or previously received azathioprine (AZA) or mercaptopurine (MP) for UC were compared with 130 controls. Charts were reviewed and logistic regression analyses were applied to identify factors associated with AZA or MP use.

Results  In univariate model, seven factors at diagnosis correlated with AZA use: male gender [odds ratio (OR) 2.2]; left‐sided or extensive colitis or pancolitis (OR 8.7–14.1); systemic steroid use within the first 6 months of diagnosis (OR 5.1); more than 10 bowel movements daily (OR 6.4); persistent or mostly blood in stool (OR 2.8); endoscopic proven moderate to severe disease (OR 7.2–12.0) and requirement of hospitalization (OR 2.7) on diagnosis. In multivariate model, the first three factors were shown to be statistically significant.

Conclusion  Male gender, initial presentation with severe and extensive disease clinically and endoscopically, requirement of hospitalization on diagnosis or systemic steroids within 6 months of diagnosis are predictive factors for immunosuppressant use in UC.
Assessment of antimicrobial microspheres as a prospective novel treatment targeted towards the repair of perianal fistulae
Authors: BLAKER J. J. , PRATTEN J. , READY D. , KNOWLES J. C. , FORBES A. , DAY R. M.
Published: October 2008

Background  None of the proposed materials tested for the management of perianal fistulae has proven to be a definitive treatment.

Aim  To assess a new repair scaffold and drug delivery device conceived to target perianal fistula repair.

Methods  Poly(d,l‐lactide‐co‐glycolide) porous microspheres containing either antibacterial silver‐releasing degradable phosphate glass or metronidazole were prepared using thermally induced phase separation.

Results  Ion‐ and drug‐release profiling of the microspheres revealed continued release of silver ions from microspheres filled with silver‐doped phosphate glass and high encapsulation efficiency for metronidazole [78% and 82% for microspheres loaded with 2.5% and 1.3% (w/w), respectively]. Microbicidal activity was confirmed by growth inhibition of bacterial species (Staphylococcus aureus, Escherichia coli and Bacteroides fragilis), which characteristically dominate the colonization of perianal fistula tracts. Microspheres containing >3 mol% silver or metronidazole resulted in strong bacterial inhibition/kill against B. fragilis; the presence of one sphere containing >3 mol% silver had a potent inhibitory effect against all the microbes studied. Microspheres became rapidly integrated with host tissue following subcutaneous implantation into a rodent wound model.

Conclusion  The study demonstrates a novel scaffold for guided tissue regeneration providing local release of antimicrobial agents sufficient to counter bacterial colonization and warrants further investigation.
Clinical trial: the glucagon‐like peptide‐1 analogue ROSE‐010 for management of acute pain in patients with irritable bowel syndrome: a randomized, placebo‐controlled, double‐blind study
Authors: HELLSTRÖM P. M. , HEIN J. , BYTZER P. , BJÖRNSSÖN E. , KRISTENSEN J. , SCHAMBYE H.
Published: October 2008

Background  There is currently no treatment available to manage acute pain attacks in IBS patients regardless of subtype.

Aims  To evaluate efficacy and safety of the GLP‐1 analogue ROSE‐010 in patients with irritable bowel syndrome (IBS) through a randomized, double‐blind, placebo‐controlled study.

Methods  Eligible patients (n = 166) meeting Rome II criteria were randomly assigned to receive single subcutaneous injections of ROSE‐010 100 μg, 300 μg and placebo in a cross‐over design. Safety was assessed from spontaneously reported adverse events and measurement of vital signs. Patient‐rated pain relief and intensity were measured on a 100‐mm visual analogue scale. The primary efficacy variable was proportion of patients with >50% maximum total pain relief response from 10 to 60 min after treatment. Secondary endpoints included the maximum summed pain intensity difference, time to meaningful pain relief and patient ratings of satisfaction with treatment.

Results  Twice as many patients were responders in the primary efficacy endpoint after both ROSE‐010 injections compared to placebo (24%P = 0.011, 23%P = 0.005, and 12% after 300 μg, 100 μg and placebo injections, respectively). Similar results were obtained for the proportion of patients with total pain intensity response. Times to meaningful and total pain relief were shorter for both doses of ROSE‐010 compared with placebo. Compared with placebo, more patients (P < 0.05) were satisfied with ROSE‐010 and considered ROSE‐010 better than previous IBS medications used.

Conclusion  ROSE‐010 was well tolerated and provided fast and effective relief of acute pain attacks on demand in IBS patients.
Validation of the quality of The National Pain Database for pain management services in the United Kingdom
Authors: Hall G. C. , Bryant T. N. , Merrett L. K. , Price C.
Published: October 2008

Data on specialist pain management is scarce. We evaluated PainDB, a database which aggregates this information from UK pain clinics. PainDB entries for 1120 patients (2648 consultations) were compared to records at 30 pain clinics. Staff were surveyed about normal practice at 28 sites. First consultations (17 135) on the aggregated PainDB were analysed for 2003 for omissions. Those consultations included on PainDB (54.6%) showed good concurrence with written notes (88.1%), with no pattern for the missing visits. Questionnaire responses were often absent from notes (56%) and diagnosis was most frequently omitted from PainDB (12.4–18.4%). Clinic staff overestimated completeness. Despite commitment, PainDB is currently unsuitable for research or audit. As routine hospital data should provide information on activity, specific questions on severity and outcome could be answered by short‐term recording of predefined variables.
A survey of the use of ultrasound guidance in internal jugular venous cannulation*
Authors: McGrattan T. , Duffty J. , Green J. S. , O’Donnell N.
Published: October 2008

It has been that suggested the use of two dimensional (2D) ultrasound to facilitate placement of central venous cannulae in the internal jugular vein improves patient safety and reduces complications. Since the introduction of the National Institute for Clinical Excellence Technology Appraisal Guideline Number 49 in 2002, promoting the use of ultrasound in placement of internal jugular venous cannulae, utilisation of ultrasound has increased throughout the United Kingdom. We report the findings of a postal survey of 2000 senior anaesthetists in the United Kingdom which enquired about their use of ultrasound for internal jugular vein cannulae placement. Only 27% use 2D ultrasound as their first choice technique, although 35% use it as their first choice when teaching. There was no significant difference in practice between those working within a sub specialty in anaesthesia. There continues to be discrepancies between the application of the guideline and how senior anaesthetists both site and teach the placement of internal jugular vein central venous cannulae.
Unplanned extubation in a paediatric intensive care unit: impact of a quality improvement programme
Authors: Da Silva P. S. L. , De Aguiar V. E. , Neto H. M. , De Carvalho W. B.
Published: October 2008

Unplanned tracheal extubation is an important quality issue in current medical practice as it is a common occurrence in paediatric intensive care units. We have assessed the effectiveness of a continuous quality improvement programme in reducing the incidence of unplanned extubation over a 5‐year period. After a 2‐year baseline period, we developed action plans to address the issues identified. Following implementation of the programme, the overall incidence of unplanned extubation decreased from 2.9 unplanned extubations per 100 intubated patient days in the first year to 0.6 in the last year (p = 0.0001). This reduction was the result of a decrease in unplanned extubation in children younger than 2 years of age. Although mortality was similar to that of children who did not experience an unplanned extubation, those with an unplanned extubation had a significantly longer duration of mechanical ventilation, longer stay in the intensive care unit, and longer hospital stay. We found that the implementation of a continuous quality improvement programme is effective in reducing the overall incidence of unplanned extubations.
Emergency cricothyroidotomy: a randomised crossover study of four methods
Authors: Dimitriadis J. C. , Paoloni R.
Published: October 2008

Emergency physicians and registrars performed emergency cricothyroidotomy on an artificial airway model using a standard surgical approach and three common commercial products, participants had received no refresher training. The order in which the methods were used was randomised to minimise any learning effect. Three methods (standard surgical, Minitrach II, and Quicktrach) were universally successful in obtaining ventilation within 150 s, whilst the Melker kit had a 26% failure rate and significantly longer median time to ventilation (126 s vs≤48 s for other methods, p < 0.001). Despite success in using the surgical method, the Quicktrach and Minitrach II were rated as first or second preference by the majority of operators (78% and 70% respectively). Without refresher training emergency physicians and registrars successfully performed emergency cricothyroidotomy using the standard surgical method, Quicktrach and Minitrach II kits however the use of the Melker kit under these conditions resulted in significant delays or failure to establish an airway.
Assessment of a new disposable introducer for spinal needles
Authors: Erskine R. J.
Published: October 2008

The compatibility between spinal needles and their introducers varies between manufacturers and can significantly influence the usable length of the spinal needle available resulting in failure to locate CSF in larger patients. The usable length of 90‐mm pencil point spinal needles from four manufacturers ranged from 68 to 79 mm when the needle was used in combination with its introducer. A new purpose‐built introducer needle is described which, when used with a 25 g or finer spinal needle, maximises the usable length of the needle. Using this new introducer the usable needle length of a 90‐mm Whitacre needle was increased by a further 7 to 86 mm resulting in only a 4 mm loss of total needle length. The new introducer was well received by users.
Increased temperature sensitivity of net DOC production from ombrotrophic peat due to water table draw‐down
Authors: CLARK J. M. , ASHLEY D. , WAGNER M. , CHAPMAN P. J. , LANE S. N. , EVANS C. D. , HEATHWAITE A. L.
Published: October 2008

The production and release of dissolved organic carbon (DOC) from peat soils is thought to be sensitive to changes in climate, specifically changes in temperature and rainfall. However, little is known about the actual rates of net DOC production in response to temperature and water table draw‐down, particularly in comparison to carbon dioxide (CO2) fluxes. To explore these relationships, we carried out a laboratory experiment on intact peat soil cores under controlled temperature and water table conditions to determine the impact and interaction of each of these climatic factors on net DOC production. We found a significant interaction (P< 0.001) between temperature, water table draw‐down and net DOC production across the whole soil core (0 to −55 cm depth). This corresponded to an increase in theQ10(i.e. rise in the rate of net DOC production over a 10 °C range) from 1.84 under high water tables and anaerobic conditions to 3.53 under water table draw‐down and aerobic conditions between −10 and − 40 cm depth. However, increases in net DOC production were only seen after water tables recovered to the surface as secondary changes in soil water chemistry driven by sulphur redox reactions decreased DOC solubility, and therefore DOC concentrations, during periods of water table draw‐down. Furthermore, net microbial consumption of DOC was also apparent at − 1 cm depth and was an additional cause of declining DOC concentrations during dry periods. Therefore, although increased temperature and decreased rainfall could have a significant effect on net DOC release from peatlands, these climatic effects could be masked by other factors controlling the biological consumption of DOC in addition to soil water chemistry and DOC solubility. These findings highlight both the sensitivity of DOC release from ombrotrophic peat to episodic changes in water table draw‐down, and the need to disentangle complex and interacting controls on DOC dynamics to fully understand the impact of environmental change on this system.
Tree age, disturbance history, and carbon stocks and fluxes in subalpine Rocky Mountain forests
Authors: BRADFORD J. B. , BIRDSEY R. A. , JOYCE L. A. , RYAN M. G.
Published: October 2008

Forest carbon stocks and fluxes vary with forest age, and relationships with forest age are often used to estimate fluxes for regional or national carbon inventories. Two methods are commonly used to estimate forest age: observed tree age or time since a known disturbance. To clarify the relationships between tree age, time since disturbance and forest carbon storage and cycling, we examined stands of known disturbance history in three landscapes of the southern Rocky Mountains. Our objectives were to assess the similarity between carbon stocks and fluxes for these three landscapes that differed in climate and disturbance history, characterize the relationship between observed tree age and time since disturbance and quantify the predictive capability of tree age or time since disturbance on carbon stocks and fluxes. Carbon pools and fluxes were remarkably similar across the three landscapes, despite differences in elevation, climate, species composition, disturbance history, and forest age. Observed tree age was a poor predictor of time since disturbance. Maximum tree age overestimated time since disturbance for young forests and underestimated it for older forests. Carbon pools and fluxes were related to both tree age and disturbance history, but the relationships differed between these two predictors and were generally less variable for pools than for fluxes. Using tree age in a relationship developed with time since disturbance orvice versaincreases errors in estimates of carbon stocks or fluxes. Little change in most carbon stocks and fluxes occurs after the first 100 years following stand‐replacing disturbance, simplifying landscape scale estimates. We conclude that subalpine forests in the Central Rocky Mountains can be treated as a single forest type for the purpose of assessment and modeling of carbon, and that the critical period for change in carbon is < 100 years.
The experiences of prenatal depression among Taiwanese women
Authors: Tseng Ying‐Fen , Hsu Chen‐Mei , Liu Yu‐Hsiang , Chen Chung‐Hey
Published: October 2008

Title.  The experiences of prenatal depression among Taiwanese women.

Aim.  This paper is a report of a study to describe Taiwanese women’s experiences of prenatal depression.

Background.  Despite its long‐term adverse effects for both mother and child, prenatal depression has received less scholarly attention than postpartum depression. Studies to date have proposed structured measures for quantifying prenatal depression, but the characteristics of this phenomenon have not been qualitatively analysed.

Method.  A convenience sample of 12 Taiwanese pregnant women scoring above 15 on the Edinburgh Perinatal Depression Scale participated in in‐depth interviews during 2005. The interviews were transcribed verbatim and analysed using content analysis.

Findings.  Unbalanced commitment to motherhood was the primary theme of the life experiences of prenatal depression in these Taiwanese women, which summarized their feelings of engagement and ambivalence towards their experiences of transition to motherhood. Five recurring sub‐themes were identified: multiple conflicting roles, lack of social support, dissatisfaction with body image, future uncertainty and emotional instability.

Conclusion.  Prenatal depression is a painful growth experience represented by silent and unbalanced commitment during the maternal role transition. Our findings may help healthcare professionals to understand the vulnerable experiences of pregnant women and devise preventive intervention strategies, such as prenatal education for both parents and comprehensive screening for prenatal depression in at‐risk pregnant women, so that they are better prepared for the transition to motherhood.
The use of physical restraint in institutional care of older people in Finland: nurses’ individual, communal and alternative modes of action
Authors: Saarnio Reetta , Isola Arja , Laukkala Helena
Published: October 2008

Aims and objectives.  The aim of the study was to map nursing staff’s individual, communal and alternative modes of action in situations where they used physical restraint of older people in Finland.

Background.  The use of physical restraint in institutional care of older people involves modes of action that are linked to the personalities and modes of operation of individual nurses or to communal modes of operation mutually agreed on in the workplace. Nurse’s individual modes of operation are linked to consideration towards older people when using physical restraint. Communal modes of operation include joint discussion among nurses, decision‐making and written guidelines concerning the use of physical restraint.

Design.  A quantitative survey.

Methods.  The data were collected from nurses (n = 1148) working in healthcare centre wards, municipal and private nursing homes in Finland using a structured questionnaire (response rate 78%).

Results.  Older nurses and those with the longest working experience were most active in using individual modes of operation in situations where physical restraint was applied. Nurses’ participation in continuing education in care of older people increased the use of both individual and alternative modes of action. The alternative modes of action were one that understands the older person and one that focuses on negotiation. The use of physical restraint was often discussed in the workplace during information sessions or during work, but only 33% had written guidelines on the use of physical restraint.

Conclusions.  Education can be used to increase nurses’ ability to use alternative modes of action and thus decrease the use of physical restraint in institutional care of older people. Nursing management has a key role in making sure that units caring for older people receive written guidelines on the use of physical restraint.

Relevance to clinical practice.  Locums especially need more education to avoid the use of physical restraint.
Pedigree reconstruction in wild cichlid fish populations
Authors: KOCH MARTIN , HADFIELD JARROD D. , SEFC KRISTINA M. , STURMBAUER CHRISTIAN
Published: October 2008

It is common practice to use microsatellites to detect parents and their offspring in wild and captive populations, in order to reconstruct a pedigree. However, correct inference is often constrained by a number of factors, including the absence of demographic data and ignorance regarding the completeness of parental sampling. Here we present a new Bayesian estimator that simultaneously estimates the pedigree and the size of the unsampled population. The method is robust to genotyping error, and can estimate pedigrees in the absence of demographic data. Using a large‐scale microsatellite assay in four wild cichlid fish populations of Lake Tanganyika (1000 individuals in total), we assess the performance of the Bayesian estimator against the most popular assignment program, Cervus. We found small but significant pedigrees in each of the tested populations using the Bayesian procedure, but Cervus had very high type I error rates when the size of the unsampled population was assumed to be lower than what it was. The need of pedigree relationships to infer adaptive processes in natural populations places strong constraints on sampling design and identification of multigenerational pedigrees in natural populations.
Avian haematozoan parasites and their associations with mosquitoes across Southwest Pacific Islands
Authors: ISHTIAQ F. , GUILLAUMOT L. , CLEGG S. M. , PHILLIMORE A. B. , BLACK R. A. , OWENS I. P. F. , MUNDY N. I. , SHELDON B. C.
Published: October 2008

The degree to which haematozoan parasites can exploit a range of vectors and hosts has both ecological and evolutionary implications for their transmission and biogeography. Here we explore the extent to which closely related mosquito species share the same or closely related haematozoan parasites, and examine the overlap in parasite lineages with those isolated from avian hosts,Zosteropsspecies, sampled across the same study sites. Mosquito samples were collected and analysed (14 species,n = 804) from four islands in Vanuatu and the main island of New Caledonia. Using polymerase chain reaction, 15.5% (14/90) of pooled mosquito (thoracic) samples showed positive amplifications. Subsequent phylogenetic analysis of the cytochromebgene identified four genetically distinctPlasmodiumand twoHaemoproteuslineages from these samples, five of which were identical to parasite lineages (n = 21) retrieved from the avian hosts. We found that threePlasmodiumlineages differing by a maximum of 0.9% sequence divergence were recovered from different species and genera of mosquitoes and twoHaemoproteuslineages differing by 4.6% sequence divergence were carried by 10 distantly related (11–21% divergent) mosquito species. These data suggest a lack of both cospeciation and invertebrate host conservatism. Without experimental demonstration of the transmission cycle, it is not possible to establish whether these mosquitoes are the biological vectors of isolated parasite lineages, reflecting a limitation of a purely polymerase chain reaction‐based approach. Nonetheless, our results raise the possibility of a new transmission pathway and highlight extensive invertebrate host shifts in an insular mosquito–parasite system.
Pronounced reproductive skew in a natural population of green swordtails,Xiphophorus helleri
Authors: TATARENKOV ANDREY , HEALEY CHRISTIANE I. M. , GRETHER GREGORY F. , AVISE JOHN C.
Published: October 2008

For many species in nature, a sire's progeny may be distributed among a few or many dams. This poses logistical challenges — typically much greater across males than across females — for assessing means and variances in mating success (number of mates) and reproductive success (number of progeny). Here we overcome these difficulties by exhaustively analyzing a population of green swordtail fish (Xiphophorus helleri) for genetic paternity (and maternity) using a suite of highly polymorphic microsatellite loci. Genetic analyses of 1476 progeny from 69 pregnant females and 158 candidate sires revealed pronounced skews in male reproductive success both within and among broods. These skews were statistically significant, greater than in females, and correlated in males but not in females with mating success. We also compare the standardized variances in swordtail reproductive success to the few such available estimates for other taxa, notably several mammal species with varied mating systems and degrees of sexual dimorphism. The comparison showed that the opportunity for selection on maleX. helleriis among the highest yet reported in fishes, and it is intermediate compared to estimates available for mammals. This study is one of a few exhaustive genetic assessments of joint‐sex parentage in a natural fish population, and results are relevant to the operation of sexual selection in this sexually dimorphic, high‐fecundity species.
Transcriptomic variation and plasticity in rufous‐collared sparrows (Zonotrichia capensis) along an altitudinal gradient
Authors: CHEVIRON ZACHARY A. , WHITEHEAD ANDREW , BRUMFIELD ROBB T.
Published: October 2008

As modern genomic tools are developed for ecologically compelling models, field manipulation experiments will become important for establishing the role of functional genomic variation in physiological acclimation and evolutionary adaptation along environmental clines. High‐altitude habitats expose individuals to hypoxic and thermal stress, necessitating physiological acclimation, which may result in evolutionary adaptation. We assayed skeletal muscle transcriptomic profiles of rufous‐collared sparrows (Zonotrichia capensis) distributed along an altitudinal gradient on the Pacific slope of the Peruvian Andes. Nearly 200 unique transcripts were differentially expressed between high‐altitude [4100 m above sea level (a.s.l.)] and low‐altitude (2000 m a.s.l.) populations in their native habitats. Gene ontology and network analyses revealed that these transcripts are primarily involved in oxidative phosphorylation, protein biosynthesis, signal transduction and oxidative stress response pathways. To assess the plasticity in gene expression differences between populations, we performed a ‘common garden’ experiment in which high‐ and low‐altitude individuals were transferred to a common low‐altitude site (~150 m). None of the genes that were differentially expressed between populations at the native altitudes remained significantly different between populations in the common garden. The role of gene expression variation in adaptation and acclimation to environmental stress is largely unexplored in natural populations of birds. These results demonstrate substantial plasticity in the biochemical pathways that underpin cold and hypoxia compensation in Z. capensis, which may mechanistically contribute to enabling the broad altitudinal distribution of the species.
Reduced introgression of the Y chromosome between subspecies of the European rabbit (Oryctolagus cuniculus) in the Iberian Peninsula
Authors: GERALDES A. , CARNEIRO M. , DELIBES‐MATEOS M. , VILLAFUERTE R. , NACHMAN M. W. , FERRAND N.
Published: October 2008

The role of the Y chromosome in speciation is unclear. Hybrid zones provide natural arenas for studying speciation, as differential introgression of markers may reveal selection acting against incompatibilities. Two subspecies of the European rabbit (Oryctolagus cuniculus) form a hybrid zone in the Iberian Peninsula. Previous work on mitochondrial DNA (mtDNA), Y‐ and X‐linked loci revealed the existence of two divergent lineages in the rabbit genome and that these lineages are largely subspecies‐specific for mtDNA and two X‐linked loci. Here we investigated the geographic distribution of the two Y chromosome lineages by genotyping two diagnostic single nucleotide polymorphisms in a sample of 353 male rabbits representing both subspecies, and found that Y chromosome lineages are also largely subspecies‐specific. We then sequenced three autosomal loci and discovered considerable variation in levels of differentiation at these loci. Finally, we compared estimates of population differentiation between rabbit subspecies at 26 markers and found a surprising bimodal distribution of FST values. The vast majority of loci showed little or no differentiation between rabbit subspecies while a few loci, including the SRY gene, showed little or no introgression across the hybrid zone. Estimates of population differentiation for the Y chromosome were surprisingly high given that there is male‐biased dispersal in rabbits. Taken together, these data indicate that there is a clear dichotomy in the rabbit genome and that some loci remain highly differentiated despite extensive gene flow following secondary contact.
Mechanistic insight into the ribosome biogenesis functions of the ancient protein KsgA
Authors: Connolly Keith , Rife Jason P. , Culver Gloria
Published: October 2008

While the general blueprint of ribosome biogenesis is evolutionarily conserved, most details have diverged considerably. A striking exception to this divergence is the universally conserved KsgA/Dim1p enzyme family, which modifies two adjacent adenosines in the terminal helix of small subunit ribosomal RNA (rRNA). While localization of KsgA on 30S subunits [small ribosomal subunits (SSUs)] and genetic interaction data have suggested that KsgA acts as a ribosome biogenesis factor, mechanistic details and a rationale for its extreme conservation are still lacking. To begin to address these questions we have characterized the function of Escherichia coli KsgA in vivo using both a ksgA deletion strain and a methyltransferase‐deficient form of this protein. Our data reveal cold sensitivity and altered ribosomal profiles are associated with a ΔksgA genotype in E. coli. Our work also indicates that loss of KsgA alters 16S rRNA processing. These findings allow KsgAs role in SSU biogenesis to be integrated into the network of other identified factors. Moreover, a methyltransferase‐inactive form of KsgA, which we show to be deleterious to cell growth, profoundly impairs ribosome biogenesis‐prompting discussion of KsgA as a possible antimicrobial drug target. These unexpected data suggest that methylation is a second layer of function for KsgA and that its critical role is as a supervisor of biogenesis of SSUs in vivo. These new findings and this proposed regulatory role offer a mechanistic explanation for the extreme conservation of the KsgA/Dim1p enzyme family.
Genetic analysis of diapause capability and association between larval and pupal photoperiodic responses in the flesh fly Sarcophaga similis
Authors: GOTO SHIN G.
Published: October 2008

Abstract A variant of the flesh fly Sarcophaga similis, which does not enter pupal diapause even under diapause‐inducing conditions, is established by artificial selection. Interline crosses of the wild‐type and the variant revealed that the diapause capability is inherited in an incomplete dominant manner. Neither sex linkage nor a maternal factor is involved in the mode of inheritance. Genetic and genetic–environmental interactions are involved in the induction of diapause. In the wild‐type, the post‐feeding larval period is prolonged in response to short days. However, in the variant, the duration of the larval period under short‐day conditions is identical to that under long‐day conditions. Long‐day responses under short‐day conditions at both the larval and pupal stages in the variant indicate that the responses are established by common factors in both stages. The factors causing the long‐day responses under short‐day conditions at different developmental stages in the variant remain to be identified. However, it is plausible to hypothesize that common factors regulate ecdysteroid release at both the larval and pupal stages, and that malfunction of the system regulating these factors triggers such ecdysteroid release, irrespective of the photoperiod. Hence, the photoperiodic responses disappear in the variant in both stages. The adult stage of the variant has a functional circadian clock, suggesting that the nondiapause phenotype is not necessarily involved in malfunction of the circadian clock.
Photosynthesis affects following night leaf conductance in Vicia faba
Authors: EASLON HSIEN MING , RICHARDS JAMES H.
Published: October 2008

Night‐time stomatal opening in C3 plants may result in significant water loss when no carbon gain is possible. The objective of this study was to determine if endogenous patterns of night‐time stomatal opening, as reflected in leaf conductance, in Vicia faba are affected by photosynthetic conditions the previous day. Reducing photosynthesis with low light or low CO2 resulted in reduced night‐time stomatal opening the following night, irrespective of the effects on daytime stomatal conductance. Likewise, increasing photosynthesis with enriched CO2 levels resulted in increased night‐time stomatal opening the following night. Reduced night‐time stomatal opening was not the result of an inability to regulate stomatal aperture as leaves with reduced night‐time stomatal opening were capable of greater night‐time opening when exposed to low CO2. After acclimating plants to long or short days, it was found that night‐time leaf conductance was greater in plants acclimated to short days, and associated with greater leaf starch and nitrate accumulation, both of which may affect night‐time guard cell osmotic potential. Direct measurement of guard cell contents during endogenous night‐time stomatal opening will help identify the mechanism of the effect of daytime photosynthesis on subsequent night‐time stomatal regulation.
Defining hybrid poplar (Populus deltoides × Populus trichocarpa) tolerance to ozone: identifying key parameters
Authors: RYAN A. , COJOCARIU C. , POSSELL M. , DAVIES W. J. , HEWITT C. N.
Published: October 2008

This study examined whether two genotypes of hybrid poplar (Populus deltoides × Populus trichocarpa), previously classified as ozone tolerant and ozone sensitive, had differing physiological and biochemical responses when fumigated with 120 nL L−1 ozone for 6 h per day for eight consecutive days. Isoprene emission rate, ozone uptake and a number of physiological and biochemical parameters were investigated before, during and after fumigation with ozone. Previous studies have shown that isoprene protects plants against oxidative stress. Therefore, it was hypothesized that these two genotypes would differ in either their basal isoprene emission rates or in the response of isoprene to fumigation by ozone.

Our results showed that the basal emission rates of isoprene, physiological responses and ozone uptake rates were all similar. However, significant differences were found in visible damage, carotenoids, hydrogen peroxide (H2O2), thiobarbituric acid reactions (TBARS) and post‐fumigation isoprene emission rates. It is shown that, although the classification of ozone tolerance or sensitivity had been previously clearly and carefully defined using one particular set of parameters, assessment of other key variables does not necessarily lead to the same conclusions. Thus, it may be necessary to reconsider the way in which plants are classified as ozone tolerant or sensitive.
Metabolome and water status phenotyping of Arabidopsis under abiotic stress cues reveals new insight into ESK1 function
Authors: LUGAN RAPHAEL , NIOGRET MARIE‐FRANÇOISE , KERVAZO LUCIE , LARHER FRANÇOIS ROBERT , KOPKA JOACHIM , BOUCHEREAU ALAIN
Published: October 2008

Metabolomic investigation of the freezing‐tolerant Arabidopsis mutant esk1 revealed large alterations in polar metabolite content in roots and shoots. Stress metabolic markers were found to be among the most significant metabolic markers associated with the mutation, but also compounds related to growth regulation or nutrition. The metabolic phenotype of esk1 was also compared to that of wild type (WT) under various environmental constraints, namely cold, salinity and dehydration. The mutant was shown to express constitutively a subset of metabolic responses which fits with the core of stress metabolic responses in the WT. But remarkably, the most specific metabolic responses to cold acclimation were not phenocopied by esk1 mutation and remained fully inducible in the mutant at low temperature. Under salt stress, esk1 accumulated lower amounts of Na+ in leaves than the WT, and under dehydration stress its metabolic profile and osmotic potential were only slightly impacted. These phenotypes are consistent with the hypothesis of an altered water status in esk1, which actually exhibited basic lower water content (WC) and transpiration rate (TR) than the WT. Taken together, the results suggest that ESK1 does not function as a specific cold acclimation gene, but could rather be involved in water homeostasis.
A putative lipase gene EXTRA GLUME1 regulates both empty‐glume fate and spikelet development in rice
Authors: Li Haoge , Xue Dawei , Gao Zhenyu , Yan Meixian , Xu Wenying , Xing Zhuo , Huang Danian , Qian Qian , Xue Yongbiao
Published: October 2008

Recent studies have shown that molecular control of inner floral organ identity appears to be largely conserved between monocots and dicots, but little is known regarding the molecular mechanism underlying development of the monocot outer floral organ, a unique floral structure in grasses. In this study, we report the cloning of the rice EXTRA GLUME1 (EG1) gene, a putative lipase gene that specifies empty‐glume fate and floral meristem determinacy. In addition to affecting the identity and number of empty glumes, mutations in EG1 caused ectopic floral organs to be formed at each organ whorl or in extra ectopic whorls. Iterative glume‐like structures or new floral organ primordia were formed in the presumptive region of the carpel, resulting in an indeterminate floral meristem. EG1 is expressed strongly in inflorescence primordia and weakly in developing floral primordia. We also found that the floral meristem and organ identity gene OsLHS1 showed altered expression with respect to both pattern and levels in the eg1 mutant, and is probably responsible for the pleiotropic floral defects in eg1. As a putative class III lipase that functionally differs from any known plant lipase, EG1 reveals a novel pathway that regulates rice empty‐glume fate and spikelet development.
Pluripotency of Arabidopsis xylem pericycle underlies shoot regeneration from root and hypocotyl explants grown in vitro
Authors: Atta Ramzy , Laurens Lieve , Boucheron‐Dubuisson Elodie , Guivarc’h Anne , Carnero Eugénie , Giraudat‐Pautot Véronique , Rech Philippe , Chriqui Dominique
Published: October 2008

We have established a detailed framework for the process of shoot regeneration from Arabidopsis root and hypocotyl explants grown in vitro. Using transgenic plant lines in which the GUS or GFP genes were fused to promoters of developmental genes (WUS, CLV1, CLV3, STM, CUC1, PLT1, RCH1, QC25), or to promoters of genes encoding indicators of the auxin response (DR5) or transport (PIN1), cytokinin (CK) response (ARR5) or synthesis (IPT5), or mitotic activity (CYCB1), we showed that regenerated shoots originated directly or indirectly from the pericycle cells adjacent to xylem poles. In addition, shoot regeneration appeared to be partly similar to the formation of lateral root meristems (LRMs). During pre‐culture on a 2, 4‐dichlorophenoxyacetic acid (2, 4‐D)‐rich callus‐inducing medium (CIM), xylem pericycle reactivation established outgrowths that were not true calli but had many characteristics of LRMs. Transfer to a CK‐rich shoot‐inducing medium (SIM) resulted in early LRM‐like primordia changing to shoot meristems. Direct origin of shoots from the xylem pericycle occurred upon direct culture on CK‐containing media without prior growth on CIM. Thus, it appeared that the xylem pericycle is more pluripotent than previously thought. This pluripotency was accompanied by the ability of pericycle derivatives to retain diploidy, even after several rounds of cell division. In contrast, the phloem pericycle did not display such developmental plasticity, and responded to CKs with only periclinal divisions. Such observations reinforce the view that the pericycle is an ‘extended meristem’ that comprises two types of cell populations. They also suggest that the founder cells for LRM initiation are not initially fully specified for this developmental pathway.