bluuebunny/crossref_metadata_2025_split huggingface dataset:
A secretory multifunctional serine protease, DegP of Plasmodium falciparum, plays an important role in thermo‐oxidative stress, parasite growth and development
Authors: Sharma Shweta , Jadli Mohit , Singh Anu , Arora Kavita , Malhotra Pawan 
Published: February 2014

Plasmodium falciparum heat shock proteins and proteases are known for their indispensable roles in parasite virulence and survival in the host cell. They neutralize various host‐derived stress responses that are deleterious for parasite growth and invasion. We report identification and functional characterization of the first DegP from an apicomplexan (P. falciparum). To determine the molecular identity and functions of the parasite‐encoded DegP, we complemented the Escherichia coli degP null mutant with a putative PfdegP gene, and the results showed that PfDegP complements the growth defect of the temperature sensitive DegP‐deficient mutant and imparts resistance to non‐permissive temperatures and oxidative stress. Molecular interaction studies showed that PfDegP exists as a complex with parasite‐encoded heat shock protein 70, iron superoxide dismutase and enolase. DegP expression is significantly induced in parasite culture upon heat shock/oxidative stress. Our data suggest that the PfDegP protein may play a role in the growth and development of P. falciparum through its ability to confer protection against thermal/oxidative stress. Antibody against DegP showed anti‐plasmodial activity against blood‐stage parasites in vitro, suggesting that PfDegP and its associated complex may be a potential focus for new anti‐malarial therapies.Structured digital abstract●PfDegP physically interacts with PfHsp70 and PfEno by anti-bait co-immunoprecipitation (View interaction)●PfDegP physically interacts with PfEno, PfSod, PfOat, PfHsp70, PfLDH and PfGpi by anti-bait co-immunoprecipitation (View interaction)●PfHsp-70 and PfDegP co-localize by fluorescence microscopy (View interaction)●PfDegP physically interacts with PfOat, PfHsp70, PfEno, PfSod, PfGpi and PfLDH by surface plasmon resonance (View interaction)●PfEno and PfDegP co-localize by fluorescence microscopy (View interaction)●PfDegP and PfHsp70 co-localize by co-sedimentation through density gradient (View interaction)
Consequences of altered temperature and food conditions for individuals and populations: a Dynamic Energy Budget analysis for Corbicula fluminea in the Rhine
Authors: Petter Gunnar , Weitere Markus , Richter Otto , Moenickes Sylvia 
Published: February 2014

Summary

On the basis of simulations at two levels of organisation (individuals and populations), we analysed the impact of altered food and temperature conditions on the Asian clam Corbicula fluminea. In particular, we addressed the role of food and temperature in explaining occasional mass mortalities.

A Dynamic Energy Budget Model (DEBM) was used for simulations at the individual level. We calibrated the DEBM successfully using experimental data on growth in length and mass of C. fluminea under four combinations of temperature and food.

The calibrated DEBM was used to simulate the annual growth in length and mass and the reproductive success under different environmental scenarios. In general, an increase in temperature and food concentration resulted in larger and heavier clams and a higher per capita rate of reproduction. However, phytoplankton densities in rivers often fluctuate strongly and densities are high only briefly. Under such conditions, our simulations suggest that the temporal interactions of temperature and food concentration are particularly important and can decisively influence annual growth.

With regard to occasional mass mortalities, it has been hypothesised that increased temperature might induce an unmet metabolic demand and hence starvation. To test this, we simulated the conditions observed in the Rhine in 2003, when there was a severe heat wave and a mass mortality. For this purpose, we used the calibrated DEBM and, in addition, integrated it into a Physiologically Structured Population Model (PSPM) to account for processes at the population level.

Based on these simulations, it seems unlikely that starvation was the main cause of the mass mortality, although not all mechanisms affecting the energy budget are fully understood. However, a prolonged negative energy budget during heat waves can increase the vulnerability of clams to direct effects of high temperatures or additional stressors and might thus be regarded as an important factor indirectly increasing mortality rates.
Effects of nutrient loading, temperature regime and grazing pressure on nutrient limitation of periphyton in experimental ponds
Authors: Trochine Carolina , Guerrieri Marcelo E. , Liboriussen Lone , Lauridsen Torben L. , Jeppesen Erik 
Published: February 2014

Summary

We studied nutrient limitation of periphytic algae (henceforth periphyton) in 24 mesocosms simulating shallow lakes with two nutrient levels, enriched (with added nitrogen, N, and phosphorus, P) and unenriched (control), and three temperature scenarios, ambient, A2 from the Intergovernmental Panel on Climate Change (IPCC) and A2 + 50%. Periphyton growth (measured as chlorophyll a) was investigated four times in situ using nutrient‐diffusing substrata. The effect of grazing was also manipulated using exclusion cages.

We found that periphyton responded differently to nutrient addition bioassays (N and P) depending on the background nutrient concentration and warming scenario. Our results indicate that single‐nutrient limitation prevailed for periphyton in our experimental temperate shallow lakes. The responses were season sensitive.

Periphyton in the unenriched mesocosms were P‐limited in early summer in the ambient and A2 scenarios, N‐limited in late summer in these two climate scenarios, not nutrient‐limited in autumn and P‐limited in spring in all climate scenarios. Periphyton in the A2 + 50% scenario showed a positive response to N and P added together in early summer.

In contrast, periphyton in the enriched mesocosms showed no clear nutrient limitation, except for short‐term periods of P limitation in the warmer systems. Grazers did not affect the quantitative response of periphyton to nutrient addition, and the concentrations of P and N as well as mean monthly temperature were the main environmental factors driving P or N limitation.

We conclude that warming in low‐productivity lakes affects the seasonality of N limitation and changes the single‐nutrient limitation of periphyton into NP co‐limitation. This last observation suggests that warming reduces the sensitivity of temperate shallow lakes to bottom‐up perturbations.
Long‐term allelopathic control of phytoplankton by the submerged macrophyte Elodea nuttallii
Authors: Vanderstukken Maarten , Declerck Steven A. J. , Decaestecker Ellen , Muylaert Koenraad 
Published: February 2014

Summary

It is well known that submerged macrophytes can suppress phytoplankton blooms in lakes and thus promote water quality and biodiversity. One of the possible mechanisms through which submerged macrophytes control phytoplankton is by producing allelochemicals that suppress phytoplankton growth rates. The in situ importance of allelopathy, however, is often questioned because it is assumed that phytoplankton communities can rapidly evolve resistance to allelochemicals.

Here, we present the results of two mesocosm experiments in which we evaluated whether the submerged macrophyte Elodea nuttallii is capable of controlling phytoplankton biomass over periods of 4 to 8 weeks. Such a timescale is long relative to the generation time of phytoplankton and is therefore expected to allow the development of resistance through compositional shifts at both population and community levels.

Although the mesocosms were inoculated with a diverse phytoplankton inoculum including species that had previously been exposed to Elodea, phytoplankton biomass remained consistently low during the course of the experiments in the treatments with Elodea. As zooplankton grazing and competition for nutrients and light by macrophytes were excluded in our experiments, this suggests that phytoplankton was controlled by allelopathy.

Dialysis bag assays, performed at the end of each mesocosm experiment, showed that phytoplankton communities from mesocosms with Elodea were equally sensitive to exudates from Elodea than phytoplankton communities from mesocosms without Elodea.

These results suggest that phytoplankton communities do not evolve resistance to allelochemicals from Elodea. This may allow Elodea to control phytoplankton in natural ecosystems over prolonged time periods through allelopathy.
Deletion of the Kv2.1 delayed rectifier potassium channel leads to neuronal and behavioral hyperexcitability
Authors: Speca D. J. , Ogata G. , Mandikian D. , Bishop H. I. , Wiler S. W. , Eum K. , Wenzel H. Jürgen , Doisy E. T. , Matt L. , Campi K. L. , Golub M. S. , Nerbonne J. M. , Hell J. W. , Trainor B. C. , Sack J. T. , Schwartzkroin P. A. , Trimmer J. S. 
Published: February 2014

AbstractThe Kv2.1 delayed rectifier potassium channel exhibits high‐level expression in both principal and inhibitory neurons throughout the central nervous system, including prominent expression in hippocampal neurons. Studies of in vitro preparations suggest that Kv2.1 is a key yet conditional regulator of intrinsic neuronal excitability, mediated by changes in Kv2.1 expression, localization and function via activity‐dependent regulation of Kv2.1 phosphorylation. Here we identify neurological and behavioral deficits in mutant (Kv2.1−/−) mice lacking this channel. Kv2.1−/− mice have grossly normal characteristics. No impairment in vision or motor coordination was apparent, although Kv2.1−/− mice exhibit reduced body weight. The anatomic structure and expression of related Kv channels in the brains of Kv2.1−/− mice appear unchanged. Delayed rectifier potassium current is diminished in hippocampal neurons cultured from Kv2.1−/− animals. Field recordings from hippocampal slices of Kv2.1−/− mice reveal hyperexcitability in response to the convulsant bicuculline, and epileptiform activity in response to stimulation. In Kv2.1−/− mice, long‐term potentiation at the Schaffer collateral – CA1 synapse is decreased. Kv2.1−/− mice are strikingly hyperactive, and exhibit defects in spatial learning, failing to improve performance in a Morris Water Maze task. Kv2.1−/− mice are hypersensitive to the effects of the convulsants flurothyl and pilocarpine, consistent with a role for Kv2.1 as a conditional suppressor of neuronal activity. Although not prone to spontaneous seizures, Kv2.1−/− mice exhibit accelerated seizure progression. Together, these findings suggest homeostatic suppression of elevated neuronal activity by Kv2.1 plays a central role in regulating neuronal network function.
Consumer response to food labels in an emerging market: the case of Romania
Authors: Festila Alexandra , Chrysochou Polymeros , Krystallis Athanasios 
Published: February 2014

AbstractThis study investigates consumer response to food labels in an emerging market. More specifically, it measures the levels of awareness, objective and perceived understanding, perceived usefulness and perceived trustworthiness of the most prominent food labels found in the Romanian market. An online survey was conducted with a convenience sample of 428 respondents (45.6% males of an average age of 30.6 years). Results revealed that for most respondents, awareness levels towards food labels are generally low, except for the Guideline Daily Amount (GDA) and the organic food labels. Objective understanding towards food labels was relatively high, especially towards those food labels that included a clear text element. Perceived understanding, perceived usefulness and perceived trustworthiness were found to be consistently high with regard to the GDA and the national organic food labels, while the European organic label scored lower. Finally, response to food labels was found to differ between aware and unaware respondents.
Risk factors for death from pandemic influenza in 1918–1919: a case–control study
Authors: Summers Jennifer A. , Stanley James , Baker Michael G. , Wilson Nick 
Published: February 2014

BackgroundDespite the persisting threat from future influenza pandemics, much is still unknown about the risk factors for death from such events, and especially for the 1918–1919 influenza pandemic.MethodsA case–control study was performed to explore possible risk factors for death from pandemic influenza among New Zealand military personnel in the Northern Hemisphere in 1918–1919 (n = 218 cases, n = 221 controls). Data were compiled from a Roll‐of‐Honour dataset, a dataset of nearly all military personnel involved in the war and archived individual records.ResultsIn the fully adjusted multivariable model, the following were significantly associated with increased risk of death from pandemic influenza: age (25–29 years), pre‐pandemic hospitalisations for a chronic condition (e.g. tuberculosis), relatively early year of military deployment, a relatively short time from enlistment to foreign service, and having a larger chest size (e.g. adjusted odds ratio for 90–99 cm versus <90 cm was 2·45; 95% CI=1·47–4·10). There were no significant associations in the fully adjusted model with military rank, occupational class at enlistment, and rurality at enlistment.ConclusionsThis is one of the first published case–control studies of mortality risk factors for the 1918–1919 influenza pandemic. Some of the findings are consistent with previous research on risk factors (such as chronic conditions and age groups), but others appear more novel (e.g., larger chest size). As all such historical analyses have limitations, there is a need for additional studies in other settings as archival World War One records become digitalised.
Influenza vaccination coverage in children with inflammatory bowel disease
Authors: Banaszkiewicz Aleksandra , Klincewicz Beata , Łazowska‐Przeorek Izabella , Grzybowska‐Chlebowczyk Urszula , Kąkol Paulina , Mytyk Aleksandra , Kofla Anna , Radzikowski Andrzej 
Published: February 2014

The aim of this study was to evaluate the influenza vaccination status among paediatric patients with inflammatory bowel disease (IBD) in Poland. This was a questionnaire‐based study. 242 patients with IBD and 142 controls were enrolled in the study. Of patients with IBD, 7·8% received an influenza vaccine, compared to 18·3% of controls (P = 0·0013). There were no statistically significant differences in time from IBD diagnosis, disease activity and in drugs, between vaccinated and non‐vaccinated IBD children. In conclusion, the data of our study demonstrate an alarmingly poor influenza vaccination status in the majority of children with IBD. Therefore, there is an unmet need to implement better influenza vaccination strategies for this group of patients.
Mid‐IR to Visible Photoluminescence, Dielectric, and Ferroelectric Properties of Er‐Doped KNLN Ceramics
Authors: Wu Xiao , Kwok K.W. 
Published: February 2014

Two mole percentage Er‐doped (K0.5Na0.5)1 − xLixNbO3 ceramics have been prepared and their dielectric, ferroelectric, and photoluminescence (PL) properties have been investigated. Under an excitation of 980 nm, the ceramics exhibit intense up‐conversion luminescent emission at 548 nm (green), weak emission at 660 nm (red) as well as strong down‐conversion luminescent emission in near‐infrared (NIR) (1.40–1.65 μm) and mid‐infrared (2.60–2.85 μm) regions. Probably due to the induced structure distortion and reduced local symmetry, the PL intensities of the green, red as well as mid‐infrared emissions are enhanced by the doping of Li+. Our results show that the Li‐doping is effective in establishing a dynamic circulatory energy process to further enhance the PL intensity of the mid‐infrared emission at the expense of the NIR emission. At the optimum doping level of Li+ (~6 mol%), the full bandwidth at half maximum of the mid‐infrared emission reaches a very large value of ~250 nm. The ceramics also exhibit good ferroelectric properties, and thus they should have great potential for multifunctional optoelectronic applications.
Investigation on Crystallization and Optical Properties of Ca1−xLaxF2+x Glass‐Ceramics
Authors: Imanieh Mohammad H. , Martín Inocencio R. , Yekta Bijan Eftekhari , Gonzalez‐Platas Javier , Creus Alberto Hernández 
Published: February 2014

Transparent oxyfluoride glass‐ceramics containing Er3+, Yb3+:Ca1−xLaxF2+x nanocrystals, which may have potential applications in the fields of solid‐state laser and luminescence, were prepared. Crystallization of Ca1−xLaxF2+x and behavior of Yb3+ and Er3+ during the heat treatment was investigated. Results showed that alumina content had a significant effect on crystallization of Ca1−xLaxF2+x in the SiO2–Al2O3–CaF2–LaF3 system. Due to the size of phase‐separated areas, the size of the crystals during the heat treatment did not change significantly. After crystallization of Ca1−xLaxF2+x in the glass, the majority of Er3+ ions incorporated into the Ca1−xLaxF2+x crystals during the heat‐treatment process. Time‐resolved luminescence of Er3+ ions in the samples around 842 nm showed that the solubility of Er3+ ions in Ca1−xLaxF3 crystals is higher than pure CaF2 crystals. The glass undergoes an enormous phase separation, which keeps the Yb3+ ions within the other separated phase. Therefore, only at high temperatures (790°C) or with a long heat‐treatment time (72 h), there is a possibility for Yb3+ ions to be incorporated into the fluorine phase.
Structure and Dielectric Properties of BaTiO3–BiYO3 Perovskite Solid Solutions
Authors: Huang Xuechen , Hao Hua , Zhang Shujun , Liu Hanxing , Zhang Wenqin , Xu Qi , Cao Minghe 
Published: February 2014

(1−x)BaTiO3–xBiYO3 [(1−x)BT–xBY] polycrystalline ceramics were prepared by solid‐state reaction method. The ceramics are in tetragonal phase when x ≤ 0.04, transform to pseudocubic at x ≥ 0.06, showing a classic ferroelectric to relaxor transition at x = 0.06, where the phase transition temperature was found to shift to higher temperature with increasing frequency. The dielectric permittivity peaks were analyzed by the modified Curie–Weiss law. Both parameters ΔTdiffuse and ΔTrelaxor were found to increase with increasing BY content, demonstrating a stronger relaxor characteristic.
Dielectric and Raman Spectroscopic Studies of Na0.5Bi0.5TiO3–BaSnO3 Ferroelectric System
Authors: Tripathy Satya Narayan , Mishra Karuna Kara , Sen Shrabanee , Pradhan Dillip K. 
Published: February 2014

A series of lead‐free perovskite solid solutions of (1 − x) Na0.5Bi0.5TiO3(NBT)—x BaSnO3(BSN), for 0.0 ≤ x ≤ 0.15 have been synthesized using a high‐temperature solid‐state reaction route. The phase transition behaviors are studied using dielectric and Raman spectroscopic techniques. The ferroelectric to relaxor phase transition temperature (TFR) and the temperature corresponding to maximum dielectric permittivity (Tm) are estimated from the temperature‐dependent dielectric data. Dielectric studies show diffuse phase transition around ~335°C in pure NBT and this transition temperature decreases with increase in x. The disappearance of x‐dependence of A1 mode frequency at ~134 cm−1 for x ≥ 0.1 is consistent with rhombohedral‐orthorhombic transition. In situ temperature dependence Raman spectroscopic studies show disappearance and discontinuous changes in the phonon mode frequencies across rhombohedral (x < 0.1)/orthorhombic (x ≥ 0.1) to tetragonal transition.
Contrasting spatio‐temporal climatic niche dynamics during the eastern and western invasions of spotted knapweed in North America
Authors: Broennimann Olivier , Mráz Patrik , Petitpierre Blaise , Guisan Antoine , Müller‐Schärer Heinz 
Published: February 2014

AbstractAimThe spotted knapweed (Centaurea stoebe), a plant native to south‐east and central Europe, is highly invasive in North America. We investigated the spatio‐temporal climatic niche dynamics of the spotted knapweed in North America along two putative eastern and western invasion routes. We then considered the patterns observed in the light of historical, ecological and evolutionary factors.LocationEurope and North America.MethodsThe niche characteristics of the east and west invasive populations of spotted knapweed in North America were determined from documented occurrences over 120 consecutive years (1890–2010). For this investigation, the 2.5 and 97.5 percentiles of values along temperature and precipitation gradients, as given by the two first axes of a principal components analysis (PCA), were calculated. We additionally measured the climatic dissimilarity between invaded sites and the native niche using a multivariate environmental similarity surface (MESS) analysis.ResultsAlong both invasion routes, the species established in regions with climatic conditions that were similar to those in the native niche. An initial spread in ruderal habitats always preceded spread in (semi‐)natural habitats. In the east, the niche gradually increased over time until it reached limits similar to the native niche. Conversely, in the west the niche abruptly expanded after an extended time lag into climates not occupied in the native range; only the native cold niche limit was conserved.Main conclusionsOur study reveals that different niche dynamics have taken place during the eastern and western invasions. This pattern indicates different combinations of historical, ecological and evolutionary factors in the two ranges. We hypothesize that the lack of a well‐developed transportation network in the west at the time of the introduction of spotted knapweed confined the species to a geographically and climatically isolated region. The invasion of dry rangelands may have been favoured during the agricultural transition in the 1930s by release from natural enemies, local adaptation and less competitive vegetation, but further experimental and molecular studies are needed to explain these contrasting niche patterns fully. Our study illustrates the need and benefit of applying large‐scale, temporally explicit approaches to understanding biological invasions.
Oestrogen receptor‐mediated expression of Olfactomedin 4 regulates the progression of endometrial adenocarcinoma
Authors: Duan Chao , Liu Xubin , Liang Shuang , Yang Zheng , Xia Meng , Wang Liantang , Chen Shangwu , Yu Li 
Published: February 2014

AbstractEndometrial adenocarcinoma is the most common tumour of the female genital tract in developed countries, and oestrogen receptor (ER) signalling plays a pivotal role in its pathogenesis. When we used bioinformatics tools to search for the genes contributing to gynecological cancers, the expression of Olfactomedin 4 (OLFM4) was found by digital differential display to be associated with differentiation of endometrial adenocarcinoma. Aberrant expression of OLFM4 has been primarily reported in tumours of the digestive system. The mechanism of OLFM4 in tumuorigenesis is elusive. We investigated OLFM4 expression in endometrium, analysed the association of OLFM4 with ER signalling in endometrial adenocarcinoma, and examined the roles of OLFM4 in endometrial adenocarcinoma. Expression of OLFM4 was increased during endometrial carcinogenesis, linked to the differentiation of endometrioid adenocarcinoma, and positively related to the expression of oestrogen receptor‐α (ERα) and progesterone receptor. Moreover, ERα‐mediated signalling regulated expression of OLFM4, and knockdown of OLFM4 enhanced proliferation, migration and invasion of endometrial carcinoma cells. Down‐regulation of OLFM4 was associated with decreased cumulative survival rate of patients with endometrioid adenocarcinoma. Our data suggested that impairment of ERα signal‐mediated OLFM4 expression promoted the malignant progression of endometrioid adenocarcinoma, which may have significance for the therapy of this carcinoma.