bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting extinction risks under climate change: coupling stochastic population models with dynamic bioclimatic habitat models
Authors: Keith David A , Akçakaya H. Resit , Thuiller Wilfried , Midgley Guy F , Pearson Richard G , Phillips Steven J , Regan Helen M , Araújo Miguel B , Rebelo Tony G
Published: August 2008

Species responses to climate change may be influenced by changes in available habitat, as well as population processes, species interactions and interactions between demographic and landscape dynamics. Current methods for assessing these responses fail to provide an integrated view of these influences because they deal with habitat change or population dynamics, but rarely both. In this study, we linked a time series of habitat suitability models with spatially explicit stochastic population models to explore factors that influence the viability of plant species populations under stable and changing climate scenarios in South African fynbos, a global biodiversity hot spot. Results indicate that complex interactions between life history, disturbance regime and distribution pattern mediate species extinction risks under climate change. Our novel mechanistic approach allows more complete and direct appraisal of future biotic responses than do static bioclimatic habitat modelling approaches, and will ultimately support development of more effective conservation strategies to mitigate biodiversity losses due to climate change.
Dogs catch human yawns
Authors: Joly-Mascheroni Ramiro M , Senju Atsushi , Shepherd Alex J
Published: August 2008

This study is the first to demonstrate that human yawns are possibly contagious to domestic dogs (Canis familiaris). Twenty-nine dogs observed a human yawning or making control mouth movements. Twenty-one dogs yawned when they observed a human yawning, but control mouth movements did not elicit yawning from any of them. The presence of contagious yawning in dogs suggests that this phenomenon is not specific to primate species and may indicate that dogs possess the capacity for a rudimentary form of empathy. Since yawning is known to modulate the levels of arousal, yawn contagion may help coordinate dog–human interaction and communication. Understanding the mechanism as well as the function of contagious yawning between humans and dogs requires more detailed investigation.
Body odour of monozygotic human twins: a common pattern of odorant carboxylic acids released by a bacterial aminoacylase from axilla secretions contributing to an inherited body odour type
Authors: Kuhn Fabian , Natsch Andreas
Published: August 2008

It is currently not fully established whether human individuals have a genetically determined, individual-specific body odour. Volatile carboxylic acids are a key class of known human body odorants. They are released from glutamine conjugates secreted in axillary skin by a specific
N
α
-acyl-glutamine-aminoacylase present in skin bacteria. Here, we report a quantitative investigation of these odorant acids in 12 pairs of monozygotic twins. Axilla secretions were sampled twice and treated with the
N
α
-acyl-glutamine-aminoacylase. The released acids were analysed as their methyl esters with comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry detection. The pattern of the analytes was compared with distance analysis. The distance was lowest between samples of the right and the left axilla taken on the same day from the same individual. It was clearly greater if the same subject was sampled on different days, but this intra-individual distance between samples was only slightly lower than the distance between samples taken from two monozygotic twins. A much greater distance was observed when comparing unrelated individuals. By applying cluster and principal component analyses, a clear clustering of samples taken from one pair of monozygotic twins was also confirmed. In conclusion, the specific pattern of precursors for volatile carboxylic acids is subject to a day-to-day variation, but there is a strong genetic contribution. Therefore, humans have a genetically determined body odour type that is at least partly composed of these odorant acids.
Photogrammetric reconstruction of high-resolution surface topographies and deformable wing kinematics of tethered locusts and free-flying hoverflies
Authors: Walker Simon M , Thomas Adrian L.R , Taylor Graham K
Published: August 2008

Here, we present a suite of photogrammetric methods for reconstructing insect wing kinematics, to provide instantaneous topographic maps of the wing surface. We filmed tethered locusts (Schistocerca gregaria) and free-flying hoverflies (Eristalis tenax) using four high-speed digital video cameras. We digitized multiple natural features and marked points on the wings using manual and automated tracking. Epipolar geometry was used to identify additional points on the hoverfly wing outline which were anatomically indistinguishable. The cameras were calibrated using a bundle adjustment technique that provides an estimate of the error associated with each individual data point. The mean absolute three-dimensional measurement error was 0.11 mm for the locust and 0.03 mm for the hoverfly. The error in the angle of incidence was at worst 0.51° (s.d.) for the locust and 0.88° (s.d.) for the hoverfly. The results we present are of unprecedented spatio-temporal resolution, and represent the most detailed measurements of insect wing kinematics to date. Variable spanwise twist and camber are prominent in the wingbeats of both the species, and are of such complexity that they would not be adequately captured by lower resolution techniques. The role of spanwise twist and camber in insect flight has yet to be fully understood, and accurate insect wing kinematics such as we present here are required to be sure of making valid predictions about their aerodynamic effects.
Gradients of precipitation and ant abundance may contribute to the altitudinal range limit of subsocial spiders: insights from a transplant experiment
Authors: Purcell Jessica , Avilés Leticia
Published: August 2008

Species range boundaries often form along environmental gradients that dictate the success of the phenotypes present in each habitat. Sociality may allow colonization of environments where related species with a solitary lifestyle cannot persist. Social spiders in the genusAnelosimusappear restricted to low- and mid-elevation moist environments in the tropics, while subsocial spiders, common at higher elevations and latitudes, appear to be absent from the lowland tropical rainforest. Here, we seek factors that may simultaneously prevent subsocialAnelosimusspecies from colonizing the lowland rainforest while favouring species with large social groups in this habitat. To this end, we transplanted small groups of a subsocial species, which contain the offspring of a single female, from cloud forest habitat in the centre of its natural range to lower montane rainforest on the range margin and to lowland rainforest outside of the species range. Groups transplanted at the range margin and below their range limit were less likely to disperse and experienced increased mortality. This was correlated with greater rainfall intensity and ant abundance. We show that protection from rainfall enhances the performance of small groups of spiders in the lowland rainforest, and suggest that predation or disturbance by ants may influence the geographical range limits of this species.
Fungal endosymbionts of plants reduce lifespan of an aphid secondary parasitoid and influence host selection
Authors: Härri Simone A , Krauss Jochen , Müller Christine B
Published: August 2008

Complex biotic interactions shape ecological communities of plants, herbivores and their natural enemies. In studies of multi-trophic interactions, the presence of small, invisible micro-organisms associated with plants and those of a fourth above-ground trophic level have often been neglected. Incorporating these neglected factors improves our understanding of the processes within a multi-trophic network. Here, we ask whether the presence of a fungal endosymbiont, which alters plant quality by producing herbivore-toxic substances, trickles up the food chain and affects the performance and host-selection behaviour of aphid secondary parasitoids. We simultaneously offered hosts from endophyte-free and endophyte-infected environments to secondary parasitoids. Older and more experienced parasitoid females discriminated against hosts from the endophyte-infected environment. Developing in lower quality hosts from the endophyte-infected environment reduced the lifespan of secondary parasitoids. This indicates that aphid secondary parasitoids can perceive the disadvantage for their developing offspring in parasitoids from the endophyte environment and can learn to discriminate against them. In the field, this discrimination ability may shift the success of primary parasitoids to endophyte-infected plants, which co-occur with endophyte-free plants. Ultimately, the control of aphids depends on complex interactions between primary and secondary parasitoids and their relative sensitivity to endophytic fungi.
Relative growth rates of predator and prey dinosaurs reflect effects of predation
Authors: Cooper Lisa Noelle , Lee Andrew H , Taper Mark L , Horner John R
Published: August 2008

Hadrosaurs grew rapidly, and quantifying their growth is key to understanding life-history interactions between predators and prey during the Late Cretaceous. In this study, we longitudinally sampled a sequence of lines of arrested growth (LAGs) from an essentially full-grown hadrosaurHypacrosaurus stebingeri(MOR 549). Spatial locations of LAGs in the femoral and tibial transverse sections of MOR 549 were measured and circumferences were calculated. For each bone, a time series of circumference data was fitted to several stochastic, discrete growth models. Our results suggest that the femur and the tibia of this specimen ofHypacrosaurusprobably followed a Gompertz curve and that LAGs reportedly missing from early ontogeny were obscured by perimedullary resorption. In this specimen, death occurred at 13 years and took approximately 10–12 years to reach 95 per cent asymptotic size. The age at growth inflection, which is a proxy for reproductive maturity, occurred at approximately 2–3 years. Comparisons with several small and large predatory theropods reveal that MOR 549 grew faster and matured sooner than they did. These results suggest thatHypacrosauruswas able to partly avoid predators by outgrowing them.
Methylphenidate amplifies long-term plasticity in the hippocampus via noradrenergic mechanisms
Authors: Dommett Eleanor J. , Henderson Emma L. , Westwell Martin S. , Greenfield Susan A.
Published: August 2008

Methylphenidate treatment is used for Attention Deficit Hyperactivity Disorder and can improve learning and memory. Previously, improvements were considered a by-product of increased attention; however, we hypothesize that methylphenidate directly alters mechanisms underlying learning and memory, and therefore examined its effects on hippocampal long-term potentiation and long-term depression. Methylphenidate enhanced both mechanisms in the absence of presynaptic changes and in a noradrenalin β-receptor-dependent manner. These findings can explain both the improved learning and memory and decreased learning selectivity found with methylphenidate treatment and constitute the first demonstration of direct actions of methylphenidate on mechanisms implicated in cognition.
Latitudinal gradients of biologically useful semi‐darkness
Authors: Mills Alexander M.
Published: August 2008

Biological rhythms and activity patterns are strongly influenced by light levels, involving both the sun and the moon. The Earth's orbit around the sun, the moon's orbit around the Earth, and the intersecting angles of planes of orbit and of rotation conspire to create temporal variability in those light levels. Organisms that are preferentially active in the semi‐darkness of twilight and moonlight must cope with these patterns of variability and are presumably adapted for the constraints and opportunities they present. Using field results for activity patterns of a model species (whip‐poor‐will: Aves: Caprimulgidae: Caprimulgus vociferus), I define biologically useful semi‐darkness by reference to the position of the sun and the percentage of moonface illuminated. For such biologically useful semi‐darkness, I then calculate latitudinal gradients and the temporal patterns of variation in those gradients. The substantial variability in night‐time illumination contributed by the lunar cycle is largely independent of latitude, except at high latitudes during periods when there is little or no dark night. The total annual duration of semi‐darkness generated by both sun and moon increases modestly with latitude. However, the seasonal variation in the distribution of that semi‐darkness increases dramatically over the same gradient. At mid and high latitudes, the availability of semi‐darkness is least around the summer solstice and greatest around the winter solstice, patterns that are likely to influence the phenology and related behaviours of the organisms experiencing them.
Late Holocene dispersal and accumulation of terrigenous sediment on Poverty Shelf, New Zealand
Authors: Kettner A. J. , Gomez B. , Hutton E. W. H. , Syvitski J. P. M.
Published: August 2008

We use coupled numerical models (HydroTrend and SedFlux) to investigate the dispersal and accumulation of sediment on Poverty Shelf, North Island, New Zealand, during the past 3 kyr. In this timeframe, we estimate that the Waipaoa River system delivered ∼10 Gt of sediment to Poverty Shelf,  5–10% of which was transported to the outer shelf and continental slope. The domain of the two‐dimensional model (SedFlux) is representative of a 30 km traverse across the shelf. Comparing the model output with seismic reflection data and a core obtained from the middle shelf shows that, without extensively modifying the governing equations or imposing unrealistic conditions on the model domain, it is possible to replicate the geometry, grain size and accumulation rate of the late Holocene mud deposit. The replicate depositional record responds to naturally and anthropogenically induced vegetation disturbance, as well as to storms forced by long‐period climatic events simulated entirely within the model domain. The model output also suggests that long‐term fluctuations in the amount and caliber of river sediment discharge, promoted by wholesale changes in the catchment environment, may be translated directly to the shelf depositional record, whereas short‐term fluctuations conditioned by event magnitude and frequency are not. Thus on Poverty Shelf, as well as in depocenters on other active continental margins which retain a much smaller proportion of the terrigeneous sediment delivered to them, flood‐generated event beds are not commonplace features in the high‐resolution sedimentary record. This is because the shelf sedimentary record is influenced more by the energy available to the coastal ocean which helps keep the sediment in suspension and facilitates its dispersal, than by basin hydrometeorology which determines the turbidity and velocity of the river plume.
Suppressive effects of nitric oxide‐releasing prednisolone NCX‐1015 on the allergic pleural eosinophil recruitment in rats
Authors: Oliveira M. S. S. , De O. Barreto E. , Zamuner S. , Pires A. L. A. , Ferreira T. P. T. , Cordeiro R. S. B. , Lagente V. , Martins M. A. , Wallace J. L. , E Silva P. M. R.
Published: August 2008

Background
The addition of a nitric oxide (NO)‐releasing moiety to prednisolone was shown to enhance the anti‐inflammatory activity of this glucocorticoid in some experimental conditions, but its effectiveness in the context of eosinophilic inflammation remains to be elucidated.

Objective
This study compared the anti‐inflammatory effect of prednisolone to a NO‐releasing derivative of prednisolone, NCX‐1015, using a model of allergen‐evoked eosinophil recruitment in rats. The efficacy of a NO‐donor compound, DETA‐NONOate, was also assessed for comparison.

Methods
Wistar rats were actively sensitized with Al(OH)3 plus ovalbumin and 14 days later challenged with antigen intrapleurally. Treatments were performed locally 1 h before challenge. Cysteinyl‐leucotrienes (Cys‐LT) and eotaxin were measured by ELISA.

Results
Antigen challenge induced an eosinophil infiltration at 12 h, maximal at 24 h. It also caused an increase in the levels of Cys‐LTs in the pleural exudate and in the expression of 5‐lipoxygenase (5‐LO) in infiltrated leucocytes at 6 h, peaking at 12 h and persisting for at least 24 h. Treatment with equimolar doses of prednisolone and NCX‐1015 inhibited the late eosinophil infiltration, although the dose required to produce maximal inhibition was about one‐tenth that of prednisolone. Cys‐LT generation and 5‐LO expression were inhibited by NCX‐1015 but not by prednisolone. Treatment with prednisolone combined with the NO‐donor DETA‐NONOate led to a greater inhibition of the eosinophilia and Cys‐LT generation as compared with either drug alone. Administration of the steroid receptor antagonist RU 486, 1 h before prednisolone and NCX‐1015, abolished the inhibitory effect of the former, under conditions where it only partially affected the latter.

Conclusions
Our findings indicate that NCX‐1015 provided a greater anti‐inflammatory effect than prednisolone on the allergic eosinophil recruitment in rats, suggesting that NO‐releasing steroids can be considered as a promising therapeutic approach to allergic diseases.
Effects of forest fire on headwater stream macroinvertebrate communities in eastern Washington, U.S.A.
Authors: MELLON CASSIE D. , WIPFLI MARK S. , LI JUDITH L.
Published: August 2008

1. Recent increases in fire frequency in North America have focused interest on potential effects on adjacent ecosystems, including streams. Headwaters could be particularly affected because of their high connectivity to riparian and downstream aquatic ecosystems through aquatic invertebrate drift and emergence.

2. Headwater streams from replicated burned and control catchments were sampled in 2 years following an intense forest fire in northeastern Washington (U.S.A.). We compared differences in benthic, drift and emergent macroinvertebrate density, biomass and community composition between five burned and five unburned catchments (14–135 ha).

3. There were significantly higher macroinvertebrate densities in burned than control sites for all sample types. Macroinvertebrate biomass was greater at burned sites only from emergence samples; in benthic and drift samples there was no significant difference between burn and control sites.

4. For all sample types, diversity was lower in the burned catchments, and the macroinvertebrate community was dominated by chironomid midges.

5. Compared to the effects of fire in less disturbed ecosystems, this study illustrated that forest fire in a managed forest may have greater effects on headwater macroinvertebrate communities, influencing prey flow to adjacent terrestrial and downstream aquatic habitats for at least the first 2 years post‐fire.
Critical evaluation of regulatory T cells in autoimmunity: are the most potent regulatory specificities being ignored?
Authors: Vandenbark Arthur A. , Offner Halina
Published: August 2008

The identification of CD4+ CD25+ Foxp3+ regulatory T (Treg) cells as natural regulators of immunity in the periphery and tissues has stimulated tremendous interest in developing therapeutic strategies for autoimmune diseases. In this review, the site of origin, antigen specificity, homing markers and cytokine profiles of Treg cells were evaluated in autoimmune colitis and type 1 diabetes, two examples in which Treg cells were effective as therapy. These studies were compared with studies of Treg cells in experimental autoimmune encephalomyelitis and multiple sclerosis, where successful therapy has not yet been achieved. Antigen‐specific Treg cells appear to have more potent activity than polyclonal Treg cells and therefore hold more promise as therapeutic agents. However, Treg cells specific for the pathogenic T effector cells themselves have largely been overlooked and deserve consideration in future studies.
Real time PCR detection of Piscirickettsia salmonis from formalin‐fixed paraffin‐embedded tissues
Authors: Karatas S , Mikalsen J , Steinum T M , Taksdal T , Bordevik M , Colquhoun D J
Published: August 2008

Piscirickettsia salmonis is the causative agent of piscirickettsiosis, a transmissible disease of salmonid fish. Diagnosis of piscirickettsiosis has traditionally been based upon identification of typical pathological changes by histological investigation, with confirmation by immunohistochemistry on formalin‐fixed, paraffin‐embedded tissues. However, implementation of more rapid confirmatory techniques, preferably with higher levels of sensitivity and possibilities for quantification, is desirable. A real‐time polymerase chain reaction (PCR) assay was designed for specific detection of P. salmonis and tested on samples extracted from formalin‐fixed paraffin‐embedded material. Construction of a PCR‐target mimic allowed determination of detection limits, linearity of the real‐time PCR and quantitative detection of P. salmonis. The present study demonstrates the capability of the described real time PCR assay for detection of P. salmonis from paraffin‐embedded material with a high degree of sensitivity and specificity. Implementation of this assay constitutes an important development for a rapid and secure diagnosis of piscirickettsiosis.
The presence of multiple c‐type cytochromes at the surface of the methanotrophic bacterium Methylococcus capsulatus (Bath) is regulated by copper
Authors: Karlsen O. A. , Lillehaug J. R. , Jensen H. B.
Published: August 2008

Identification of surface proteins is essential to understand bacterial communication with its environment. Analysis of the surface‐associated proteins of Methylococcus capsulatus (Bath) revealed a highly dynamic structure responding closely to the availability of copper in the medium in the range from ∼0 to 10 μM. Several c‐type cytochromes, including three novel multihaem proteins, are present at the cellular surface, a feature that is otherwise a peculiarity of dissimilatory metal‐reducing bacteria. At low copper concentrations, the cytochrome c553o and the cytochrome c553o family protein, encoded by the MCA0421 and MCA0423 genes, respectively, are major constituents of the surfaceome and show a fine‐tuned copper‐dependent regulation of expression. Two novel members of the cytochrome c553o family were identified: MCA0338 was abundant between 5 and 10 μM copper, while MCA2259 was detected only in the surface fraction obtained from ∼0 μM copper cultures. The presence at the bacterial surface of several c‐type cytochromes, generally involved in energy transduction, indicates strongly that redox processes take place at the bacterial surface. Due to the unique role of copper in the biology of M. capsulatus (Bath), it appears that c‐type cytochromes have essential functions in copper homeostasis allowing the cells to adapt to varying copper exposure.
Physical and mental health outcomes of prenatal maternal stress in human and animal studies: a review of recent evidence
Authors: Beydoun Hind , Saftlas Audrey F.
Published: August 2008

Prenatal maternal stress (PNMS) has been linked with adverse health outcomes in the offspring through experimental studies using animal models and epidemiological studies of human populations. The purpose of this review article is to establish a parallel between animal and human studies, while focusing on methodological issues and gaps in knowledge. The review examines the quality of recent evidence for prevailing PNMS theoretical models, namely the biopsychosocial model for adverse pregnancy outcomes and the fetal programming model for chronic diseases. The investigators used PubMed (2000–06) to identify recently published original articles in the English language literature. A total of 103 (60 human and 43 animal) studies were examined.

Most human studies originated from developed countries, thus limiting generalisability to developing nations. Most animal studies were conducted on non‐primates, rendering extrapolation of findings to pregnant women less straightforward. PNMS definition and measurement were heterogeneous across studies examining similar research questions, thus precluding the conduct of meta‐analyses. In human studies, physical health outcomes were often restricted to birth complications while mental health outcomes included postnatal developmental disorders and psychiatric conditions in children, adolescents and adults. Diverse health outcomes were considered in animal studies, some being useful models for depression, schizophrenia or attention deficit hyperactivity disorder in human populations. The overall evidence is consistent with independent effects of PNMS on perinatal and postnatal outcomes. Intervention studies and large population‐based cohort studies combining repeated multi‐dimensional and standardised PNMS measurements with biomarkers of stress are needed to further understand PNMS aetiology and pathophysiology in human populations.
Birth prevalence of congenital hypothyroidism in Mexico
Authors: Rendón‐Macías Mario E. , Morales‐García Inés , Huerta‐Hernández Emilio , Silva‐Batalla Anabel , Villasís‐Keever Miguel A.
Published: August 2008

The Mexican Institute of Social Security (IMSS) provides care for more than 40% of the Mexican population. This report constitutes the first study of the incidence of congenital hypothyroidism (CH) in Mexican children. We performed a prospective study with a population base. CH screening began in 1997 with blood samples from the heel taken 72 h after birth; from 2000, the detection strategy was changed nationwide and blood samples were taken from the umbilical cord in all newborns for determination of thyroid‐stimulating hormone (TSH) concentration. We evaluated the annual coverage. TSH concentration was measured by chemoluminescence; TSH values ≥30 µIU/mL in umbilical cord blood and 15 µIU/mL in capillary blood were considered positive cases and were confirmed through hormonal studies. The incidence and 95% confidence intervals [95% CI] were calculated.

We found that coverage within the IMSS population was 53% from 1997 to 2000 and had increased to 95% by 2001. A total of 2 777 292 children from 2 975 157 births (93%) were studied between 2000 and 2004. Of these, 4050 had a high TSH concentration leading to suspicion of CH; CH was confirmed in 1286 (32%). The resulting incidence was 4.3/10 000 livebirths [95% CI 3.6, 5.1]. With the results obtained, we conclude that the IMSS strategy of CH screening at birth ensured 95% coverage of children in the system. The birth prevalence of CH reported is among the highest in the world.
To pool or not to pool, from whether to when: applications of pooling to biospecimens subject to a limit of detection
Authors: Schisterman Enrique F. , Vexler Albert
Published: August 2008

Pooling of biological specimens has been utilised as a cost‐efficient sampling strategy, but cost is not the unique limiting factor in biomarker development and evaluation. We examine the effect of different sampling strategies of biospecimens for exposure assessment that cannot be detected below a detection threshold (DT). The paper compares use of pooled samples to a randomly selected sample from a cohort in order to evaluate the efficiency of parameter estimates.

The proposed approach shows that a pooling design is more efficient than a random sample strategy under certain circumstances. Moreover, because pooling minimises the amount of information lost below the DT, the use of pooled data is preferable (in a context of a parametric estimation) to using all available individual measurements, for certain values of the DT. We propose a combined design, which applies pooled and unpooled biospecimens, in order to capture the strengths of the different sampling strategies and overcome instrument limitations (i.e. DT). Several Monte Carlo simulations and an example based on actual biomarker data illustrate the results of the article.
Antibody responses induced by Trichobilharzia regenti antigens in murine and human hosts exhibiting cercarial dermatitis
Authors: LICHTENBERGOVÁ L. , KOLBEKOVÁ P. , KOUŘILOVÁ P. , KAŠNÝ M. , MIKEŠ L. , HAAS H. , SCHRAMM G. , HORÁK P. , KOLÁŘOVÁ L. , MOUNTFORD A. P.
Published: August 2008

Cercariae of bird schistosomes (genus Trichobilharzia) are able to penetrate the skin of mammals (noncompatible hosts), including humans, and cause a Th2‐associated inflammatory cutaneous reaction termed cercarial dermatitis. The present study measured the antibody reactivity and antigen specificity of sera obtained after experimental infection of mice and natural infection of humans. Sera from mice re‐infected with T. regenti showed a bias towards the development of antigen‐specific IgM and IgG1 antibodies and elevated levels of total serum IgE, indicative of a Th2 polarized immune response. We also demonstrate that cercariae are a source of antigens triggering IL‐4 release from basophils collected from healthy human volunteers. Analysis of sera from patients with a history of cercarial dermatitis revealed elevated levels of cercarial‐specific IgG, particularly for samples collected from adults (> 14 years old) comparedwith children (8–14 years old), although elevated levels of antigen‐specific IgE were not detected. In terms of antigen recognition, IgG and IgE antibodies in the sera of both mice and humans preferentially bound an antigen of 34 kDa. The 34 kDa molecule was present in both homogenate of cercariae, as well as cercarial excretory/secretory products, and we speculate it may represent a major immunogen initiating the Th2‐immune response associated with cercarial dermatitis.
Molecular, biological and serological variability of Zucchini yellow mosaic virus in Tunisia
Authors: Yakoubi S. , Desbiez C. , Fakhfakh H. , Wipf‐Scheibel C. , Fabre F. , Pitrat M. , Marrakchi M. , Lecoq H.
Published: August 2008

A study was conducted to better understand the population structure of Zucchini yellow mosaic virus (ZYMV), a severe virus affecting cucurbit crops worldwide, in Tunisia and to estimate whether the use of resistant cultivars may provide durable control. Analysis of the polymerase and coat protein (NIb‐CP) partial sequences of 83 isolates collected in the three main cucurbit‐growing areas in Tunisia showed that ZYMV grouped into two distinct clusters within ZYMV molecular group A. An important variability was observed in the MREK motif of the P3 protein, a motif associated with tolerance breaking in ZYMV‐tolerant zucchini squash cultivars. Interestingly, significant differences were found in the distribution of the MREK variants in the two clusters defined by the partial NIb‐CP sequences, MREK and MKEK sequences being more common in cluster 1 and cluster 2, respectively. When combining NIb‐CP and P3 sequence information, ZYMV molecular variability was shown to be significantly higher in the Cap Bon region than in the Bizerte area. An important biological variability was observed in a subset of 23 isolates regarding symptomatology in susceptible or resistant cucurbits. Some isolates overcame ZYMV tolerance or resistance in zucchini squash and melon, but not in cucumber. Three serotypes were differentiated using a set of 13 monoclonal antibodies (MAbs). Seven parameters characterizing the 23 isolates, including molecular, serological and biological properties, were used for a multiple component analysis (MCA). This analysis revealed that symptom intensity of a given isolate was similar in different susceptible cucurbit hosts, suggesting similar degrees of aggressiveness in different hosts.
Downregulation of CXCR6 and CXCR3 in Lymphocytes from Birch‐allergic Patients
Authors: Casas R. , Lindau C. , Zetterström O. , Duchén K.
Published: August 2008

Preferential expression of chemokine receptors on Th1 or Th2 T‐helper cells has mostly been studied in cell lines generated in vitro or in animal models; however, results are less well characterized in humans. We determined T‐cell responses through chemokine receptor expression on lymphocytes, and cytokine secretion in plasma from birch‐allergic and healthy subjects. The expression of CCR2, CCR3, CCR4, CCR5, CCR7, CXCR3, CXCR4, CXCR6, IL‐12 and IL‐18R receptors was studied on CD4+ and CD8+ cells from birch‐allergic (n = 14) and healthy (n = 14) subjects by flow cytometry. The concentration of IL‐4, IL‐5, IL‐10, IL‐12, IFN‐γ and TNF‐α cytokines was measured in plasma from the same individuals using a cytometric bead array human cytokines kit. The similar expression of CCR4 in T cells from atopic and healthy individuals argues against the use of the receptor as an in vivo marker of Th2 immune responses. Reduced percentages of CD4+ cells expressing IL‐18R, CXCR6 and CXCR3 were found in the same group of samples. TNF‐α, IFN‐γ, IL‐10, IL‐5, IL‐4 and IL‐12 cytokines were elevated in samples from allergic individuals. Reduced expression of Th1‐associated chemokine receptors together with higher levels of Th1, Th2 and anti‐inflammatory cytokines in samples from allergic patients indicate that immune responses in peripheral blood in atopic diseases are complex and cannot be simplified to the Th1/Th2 paradigm. Not only the clinical picture of atopic diseases but also the clinical state at different time points of the disease might influence the results of studies including immunological markers associated with Th1‐ or Th2‐type immune responses.
T‐cell activation during exacerbations: a longitudinal study in refractory asthma
Authors: Mamessier E. , Nieves A. , Lorec A.‐M. , Dupuy P. , Pinot D. , Pinet C. , Vervloet D. , Magnan A.
Published: August 2008

Background:  Asthma exacerbations represent the main source of costs and morbidity in asthma care, and drugs specifically designed to prevent exacerbations are needed. A prerequisite is to dispose of a precise knowledge of inflammatory events leading to exacerbations.

Objective:  To study T‐cell activation during exacerbations from severe refractory asthmatics.

Methods:  Proportions of blood T‐cell interleukin (IL)‐13, interferon‐γ, IL‐4, IL‐5, IL‐10 production and of CD4+CD25+highCD62L+CD45RO+ [T regulatory (Treg)] cells were determined by flow cytometry. Blood cytokine mRNA was studied by reverse transcription‐polymerase chain reaction and the respective protein levels were determined by cytokine beads array. Depletion of Treg cells was performed to study their activation. T‐cell cytokines were detected in parallel in induced sputum.

Results:  At baseline, T helper 2 (Th2) cells were increased in asthmatics, whereas T helper 1 (Th1) and Treg T cells were decreased. T helper 2 cells increased before exacerbations, followed by Th1 cells, in blood and induced sputum, albeit Treg cells decreased in parallel with IL‐10‐producing T cells. Concordant results were found at the mRNA level. The suppressive activity of Treg cells was impaired during exacerbations compared to baseline.

Conclusions:  New insights are given into pathophysiology of asthma exacerbations: Although at baseline T‐cell activation is Th2‐biased, a mixed Th1/Th2 activation occurs during exacerbations. The Treg cell deficiency found at baseline in SRA increases during exacerbations.
Glucocorticoids inhibit degranulation of mast cells in allergic asthma via nongenomic mechanism
Authors: Zhou J. , Liu D.‐F. , Liu C. , Kang Z.‐M. , Shen X.‐H. , Chen Y.‐Z. , Xu T. , Jiang C.‐L.
Published: August 2008

Background:  Glucocorticoids (GCs) are the most potent anti‐inflammatory agents available for allergic diseases including asthma, which are routinely believed to need several hours to take effect through regulating gene expression. Our previous report had shown that GCs could inhibit allergic asthma within 10 min, which the classical mechanism could not explain.

Objective:  To confirm the existence and verify the sites of GCs’ rapid action, we investigated nongenomic effects of GCs on degranulation of mast cells in allergic asthma.

Methods:  The GCs’ rapid action on airway mast cells deregulations was evaluated in the allergic asthma model of guinea pigs by the computer‐assisted morphometry. Using whole‐cell patch clamp and fluorometric assay, we examined GCs’ nongenomic effect on IgE‐mediated exocytosis and histamine release of rat basophilic leukaemia‐2H3 mast cells. Employing the flash photolysis technique, we studied the role of Ca2+ signal in the GCs’ nongenomic effect.

Results:  Inhaled GCs significantly inhibited airway mast cells degranulation in the allergic asthma model of guinea pigs within 10 min. In vitro, GCs could rapidly inhibit IgE‐mediated exocytosis and histamine release of mast cells, and neither GC nuclear receptor antagonist nor protein synthesis inhibitor could block the rapid action. We further demonstrated that GCs’ nongenomic effect was not through direct action on secretory machinery, but was mediated by a reduction in the [Ca2+]i elevation.

Conclusions:  The study suggested for the first time that nongenomic pathway was involved in GCs’ rapid inhibition on allergic asthma, and raised the possibility of new therapeutic strategies for allergic diseases including asthma.
The rate of environmental change drives adaptation to an antibiotic sink
Authors: PERRON G. G. , GONZALEZ A. , BUCKLING A.
Published: August 2008

Recent accelerated trends of human‐induced global changes are providing many examples of adaptation to novel environments. Although the rate of environmental change can vary dramatically, its effect on evolving populations is unknown. A crucial feature explaining the adaptation to harsh environments is the supply of beneficial mutations via immigration from a ‘source’ population. In this study, we tested the effect of immigration on adaptation to increasing concentrations of antibiotics. Using experimental population of Pseudomonas aeruginosa, a pathogenic bacterium, we show that higher immigration rates and a slow increase in antibiotic concentration result in a more rapid evolution of resistance; however, a high immigration rate combined with rapid increases in concentration resulted in higher maximal levels of resistance. These findings, which support recent theoretical work, have important implications for the control of antibiotic resistance because they show that rapid rates of change can produce variants with the ability to resist future treatments.
Effect of Prepartum Energetic Supplementation on Productive and Reproductive Characteristics, and Metabolic and Hormonal Profiles in Dairy Cows under Grazing Conditions
Authors: Cavestany D , Kulcsár M , Crespi D , Chilliard Y , Manna A La , Balogh O , Keresztes M , Delavaud C , Huszenicza G , Meikle A
Published: August 2008

Contents

The effect of cracked corn grain supplementation (3.5 kg/day) during 3 weeks before the expected calving date on milk production and composition, body condition score (BCS), metabolic and hormonal profiles and length of postpartum anoestrus was evaluated in multiparous Holstein dairy cows under grazing conditions (Energy supplemented group, n = 10; Control group, n = 10). Body condition score was weekly recorded during the peripartum period, from days −21 to +35 (parturition = day 0). Non‐esterified fatty acids, β‐hydroxybutyrate, cholesterol, urea, insulin, insulin‐like growth factor I (IGF‐I), leptin, thyroxine (T4) and 3,3′’5‐triiodothyroinine (T3) were weekly determined in plasma from days −21 to +35. The reinitiation of ovarian cyclicity was twice weekly determined by ovarian ultrasonography and confirmed by plasma progesterone concentrations. Cows fed energy concentrate prepartum had higher BCS during the prepartum and postpartum and produced more milk. Non‐esterified fatty acids plasma concentrations were significantly higher in the energy group, while cholesterol was higher in the control group. Treated cows had higher levels of plasma insulin, IGF‐I and leptin pre‐calving. IGF‐I, leptin and T4 were diminished during the early postpartum period in both groups. Insulin levels were also diminished in the control group, but levels remained high in the energy‐supplemented group. Treated cows ovulated sooner after parturition than controls. We conclude that Energetic supplementation prepartum in cows under grazing conditions increased milk production and reduced the reinitiation of ovarian activity, consistent with a better EB (BCS), higher prepartum levels of IGF‐I, leptin and insulin, and higher insulin levels during early postpartum.
Anomalous Pregnancies during Late Embryonic/Early Foetal Period in High Producing Dairy Cows
Authors: Serrano B , López‐Gatius F , Hunter RHF , Santolaria P , García‐Ispierto I , Bech‐Sabat G , De Sousa NM , Beckers JF , Yániz JL
Published: August 2008

Contents

This study analyses anomalous cases of gestation ending in pregnancy loss during the early foetal period and their effect on progesterone and plasma pregnancy‐associated glycoprotein‐1 (PAG‐1) concentrations. Data derived from a large‐scale ultrasound pregnancy diagnosis programme in high producing dairy cows. Over a 3‐year period (2004–2007), a very low incidence (0.5%: 15 of 3094) of anomalous pregnancies was recorded. The results revealed that the following anomalies were detected on days 35–41 of gestation in cows carrying singletons with one single corpus luteum: embryo death in eight cows (0.3%); and embryo in the uterine horn contralateral to the corpus luteum in seven cows (0.2%). All these animals suffered pregnancy loss during the early foetal period. In cows carrying dead embryos, no signs of conceptus degeneration were observed on pregnancy diagnosis. Amnion size (approximately 25 mm diameter) and uterine horn fluid contents were estimated to be similar to those of the normal pregnant cows in this period. In the contralateral gestations, live embryos were observed in all ultrasound checks before pregnancy loss. Uterine fluid contents increased in the two cows in which gestation continued for more than a week. In the cases of embryo death but not in those of contralateral gestation, a drop in PAG‐1 levels was noted prior to pregnancy loss. Two cows carrying dead embryos increased with time allantoic fluid contents. The PAG‐1 values increased with time in one cow bearing a dead embryo (from 2.31 to 6.79 ng/ml) and in two of the contralateral gestations (from 1.66 to 2.33 ng/ml and from 0.39 to 6.79 ng/ml, respectively). Results of this study indicate that the foetal membranes continue to undergo some activity following embryo death, and that contralateral pregnancy may determine failure of the gestation process.
Lactose Synthase Components in Milk: Concentrations of α‐Lactalbumin and β1,4‐Galactosyltransferase in Milk of Cows from Several Breeds at Various Stages of Lactation
Authors: Bleck GT , Wheeler MB , Hansen LB , Chester‐Jones H , Miller DJ
Published: August 2008

Contents

It is believed that milk production is determined by the number and activity of mammary secretory cells. Secretory activity, as assessed by milk volume, depends on secretion of the major osmole in milk, lactose, which is produced by lactose synthase. The amount of either of the two proteins in lactose synthase may regulate milk production. The objective of this study was to determine whether the concentrations in milk of the two components of lactose synthase, α‐lactalbumin (α‐LA) and β1,4‐galactosyltransferase (B4GALT), were related to genetic background, stage of lactation, breed or parity of dairy cows. α‐Lactalbumin and B4GALT concentrations were measured by ELISA and by enzyme assays, respectively, from single milk samples. Two herds with a total of 279 cows were used in the analysis. One herd contained Ayrshire, Brown Swiss, Holstein and Jersey cows; the second herd contained two groups of cows; Holsteins selected for high milk production and Holsteins with 1960s genetics. The α‐LA concentration in milk was greater in Jerseys and Ayrshires than in Holsteins and Brown Swiss. However, no difference in α‐LA concentration was observed in milk from high and low genetic merit cows in the Minnesota herd or among different genetic backgrounds in the Illinois herd. β1,4‐Galactosyltransferase concentrations were similar for all groups that were analyzed. α‐Lactalbumin concentrations were positively correlated with milk protein concentration, milk fat concentration and lactose concentration. β1,4‐Galactosyltransferase concentration in milk exhibited a strong positive correlation with number of days in milk. Although the concentration of B4GALT increased as lactation progressed, the values did not show any correlation with persistency of lactation or late lactation milk production. In conclusion, this survey shows that the two components of lactose synthase are each correlated to protein concentration and individually correlated to the concentration of other milk components and stage of lactation.
Reduced Immunolabelling of a Porcine Oocyte Membrane Protein Reflects Reduced Fertilizability of Porcine Oocytes Following Elevated Ambient Temperature
Authors: Berger T , Roberts BM
Published: August 2008

Contents

Decreased fertility in pigs is a common occurrence during summer months. An objective of the current experiments was to evaluate if elevated ambient temperature altered the oocyte plasma membrane including potential receptors for sperm. This would potentially contribute to reduced fertilizability. Treated gilts were exposed in vivo to 32°C for 12 h per day and 20°C for the remaining 12 h per day for 7 days; control gilts were exposed to 22°C for 12 h and 20°C for the remaining 12 h each day. Cumulus–oocyte complexes were also aspirated from ovaries obtained from gilts maintained at thermoneutral ambient temperature and matured in vitro at 38.5°C or 40°C. Relative abundance of a porcine oocyte membrane protein was examined by intensity of immunolabelling of the in vivo and in vitro matured oocytes evaluated with confocal microscopy; fertilizability of the in vitro matured oocytes was evaluated in in vitro fertilization assays. Oocytes obtained from gilts exposed to elevated ambient temperature for 7 days had reduced immunolabelling compared with oocytes from control gilts (p < 0.05). Similarly, oocytes matured in vitro for 44 h at elevated ambient temperature had reduced immunolabelling and reduced fertilizability compared with oocytes matured at 38.5°C (p < 0.01 and p < 0.05). These results suggest porcine oocyte quality is reduced by elevated ambient temperature and immunolabelling of oocytes with antibodies to specific membrane proteins may be effective to evaluate some aspects of oocyte quality.
Critical thinking dispositions and learning styles of baccalaureate nursing students from China
Authors: Zhang Huan , Lambert Vickie
Published: August 2008

Abstract  Although considerable information exists regarding the learning styles and critical thinking dispositions of nursing students from Western countries, limited comparable information exists within China. The purposes of this study were to assess the learning styles and critical thinking dispositions of Chinese baccalaureate nursing students and to identify the relationships among the learning styles, critical thinking dispositions, and demographics. The sample consisted of 100 Chinese baccalaureate nursing students enrolled at two universities. The data were obtained through a Demographic Data Questionnaire, the California Critical Thinking Disposition Inventory, and the Index of Learning Styles. The primary learning style dimensions were found to be reflective, sensing, visual, and global, while the critically thinking abilities was found to be weak. A number of positive and negative correlations were found among the demographics, learning styles, and critical thinking dispositions. These findings suggest further examination on how to increase nursing students' critical thinking skills based upon their preferred learning styles.