bluuebunny/crossref_metadata_2025_split huggingface dataset:
NoxA activation by the small GTPase RacA is required to maintain a mutualistic symbiotic association between Epichloë festucae and perennial ryegrass
Authors: Tanaka Aiko , Takemoto Daigo , Hyon Gang‐Su , Park Pyoyun , Scott Barry 
Published: April 2008

SummarySmall GTPases of the Rac group play a key regulatory role in NADPH oxidase catalysed production of reactive oxygen species (ROS) in mammals and plants, but very little evidence is available for a corresponding role in fungi. We recently showed that ROS produced by a specific fungal NADPH oxidase isoform, NoxA, are crucial in regulating hyphal morphogenesis and growth in the mutualistic symbiotic interaction between Epichloë festucae and perennial ryegrass. We demonstrate here that E. festucae RacA is required for NoxA activation and regulated production of ROS to maintain a symbiotic interaction. Deletion of racA resulted in decreased ROS production, reduction of radial growth and hyper‐branching of the hyphae in culture. In contrast, in planta the racA mutant showed extensive colonization of the host plant, resulting in stunting and precocious senescence of the host plants. Strains expressing a dominant active (DA) allele of RacA had increased ROS production, increased aerial hyphae and reduced radial growth. These results demonstrate that RacA plays a crucial role in regulating ROS production by NoxA, in order to control hyphal morphogenesis and growth of the endophyte in planta.
Resistance of the Echinococcus granulosus cyst wall to complement activation: analysis of the role of InsP6 deposits
Authors: IRIGOÍN F. , LAICH A. , FERREIRA A. M. , FERNÁNDEZ C. , SIM R. B. , DÍAZ A. 
Published: April 2008

SUMMARY The larva of the cestode Echinococcus granulosus (hydatid cyst) is protected by the acellular laminated layer (LL). The mechanisms that make this thick coat a poor activator of host complement are incompletely understood. The structure binds, through unknown motifs, the host regulator of the alternative complement pathway (ACP), factor H. A second potential mechanism of ACP regulation, the inhibition of factor B activation, was detected in assays employing purified components (Immunopharmacology 42 : 91). The inhibitor was subsequently identified as myo‐inositol hexakisphosphate (InsP6), which in the form of nano‐deposits is a major component of the LL (Biochem J 362 : 297; J Cell Biochem 93 : 1272; FEBS J 273 : 3192). In this report we show that colloidal InsP6 solids inhibit factor B activation, through adsorption and associated impairment of C3b binding. However, this interaction is not relevant in the presence of serum proteins. In serum, InsP6 deposits instead bind C1q, and initiate complement activation. This activation is curtailed through efficient C3b inactivation, previously shown to be entirely factor H‐dependent, and now observed to be independent of the InsP6 deposits. Therefore the complement resistance of the LL must be based on functional factor H binding sites present on the mucin‐based meshwork that is its other major constituent.
Seasonal differences in photosynthesis between the C3and C4subspecies ofAlloteropsis semialataare offset by frost and drought
Authors: IBRAHIM DOUGLAS G. , GILBERT MATTHEW E. , RIPLEY BRAD S. , OSBORNE COLIN P. 
Published: April 2008

ABSTRACTThe regional abundance of C4grasses is strongly controlled by temperature, however, the role of precipitation is less clear. Progress in elucidating the direct effects of photosynthetic pathway on these climate relationships is hindered by the significant genetic divergence between major C3and C4grass lineages. We addressed this problem by examining seasonal climate responses of photosynthesis inAlloteropsis semialata, a unique grass species with both C3and C4subspecies. Experimental manipulation of rainfall in a common garden in South Africa tested the hypotheses that: (1) photosynthesis is greater in the C4than C3subspecies under high summer temperatures, but this pattern is reversed at low winter temperatures; and (2) the photosynthetic advantage of C4plants is enhanced during drought events. Measurements of leaf gas exchange over 2 years showed a significant photosynthetic advantage for the C4subspecies under irrigated conditions from spring through autumn. However, the C4leaves were killed by winter frost, while photosynthesis continued in the C3plants. Unexpectedly, the C4subspecies also lost its photosynthetic advantage during natural drought events, despite greater water‐use efficiency under irrigated conditions. This study highlights previously unrecognized roles for climatic extremes in determining the ecological success of C3and C4grasses.
Heat acclimation and cross‐tolerance against anoxia in Arabidopsis
Authors: BANTI VALERIA , LORETI ELENA , NOVI GIACOMO , SANTANIELLO ANTONIETTA , ALPI AMEDEO , PERATA PIERDOMENICO 
Published: April 2008

ABSTRACT Arabidopsis seedlings are highly sensitive to low oxygen and they die rapidly when exposed to anoxia. Tolerance to anoxia depends on the ability to efficiently use carbohydrates through the fermentative pathway, as highlighted by the lower tolerance displayed by a mutant devoid of alcohol dehydrogenase. Other mechanisms of tolerance are also possible and may include a role for heat‐induced genes. In fact, heat shock proteins (HSPs) are induced by anoxia. This suggests that there may be a cross‐adaptation mechanism between heat and anoxic stress, and in this work, we studied the acclimation of Arabidopsis seedlings both to low oxygen and heat. The results show that seedlings subjected to hypoxia or heat pretreatment survive anoxia much better. Interestingly, we also observed an increased anoxia tolerance in heat‐treated alcohol dehydrogenase (adh) mutant plants. On the other hand, anoxic pretreatment does not confer tolerance to heat stress. The success of the induction of HSPs by anoxia is in direct relation to the amount of sucrose available, and this in turn relates to how well seedlings will survive under anoxia. HSP transcripts were also detected during seed development and germination, two hypoxia‐prone processes, suggesting that hypoxia‐induced HSP expression is physiologically relevant.
Individual Signature in Canary Songs: Contribution of Multiple Levels of Song Structure
Authors: Lehongre Katia , Aubin Thierry , Robin Stéphane , Del Negro Catherine 
Published: April 2008

AbstractThrough variations in features, both within and between individuals, songs of male passerines provide information on the identity of the singer. In domesticated canaries (Serinus canaria), these variations remain, for a large part, to be investigated. This led us to question whether individual identity might be coded at one or more hierarchical levels of song organization, i.e. in acoustic parameters, in the syllable repertoire and in the delivery order of syllables. A song as a whole had numerous individual distinctive acoustic features. However, the structure of its individual signature appeared to be complex. A repertoire combined syllables never sung by other individuals with those shared by other birds. But, most of the individual‐specific syllables that accounted for 16% of a repertoire did not recur frequently. Variation in sequences of multiple syllable types appeared to reflect the individual identity of a male canary. Nearly all sequences larger than three syllable types were specific to the individual that produced them. Some of these occurred recurrently in songs and differed in their acoustic structure between individuals. Focusing upon recurrent sequences might allow vocal recognition of an individual without requiring the knowledge of its full repertoire. However, acoustic parameters and repertoire composition might also serve as additional cues to limit confusion between individuals.
Pupal Period Affects Calling Behavior of the Wheat Moth, Pseudaletia sequax (Lepidoptera: Noctuidae)
Authors: Almeida Ângela A. , Lima Eraldo R. , Reis Ronaldo 
Published: April 2008

AbstractThe effects of pupal period and age on calling behavior of virgin females of Pseudaletia sequax were determined. Calling behavior of groups of females of similar age of pupation was observed every 10 min for six calling days. Females were considered calling when they assumed a characteristic position: wings and abdomen elevated, displaying the ovipositor and presumably releasing pheromone. Calling behavior was discontinuous. Females with a shorter pupal period took more time to start calling than females with a longer pupal period and called for a longer period. On the first day of calling, females took more time to initiate calling, on average during the seventh hour of the scotophase, whereas on the second day of calling, most females initiated calling during the fifth hour of the scotophase. On subsequent days of calling, the average time to initiate calling changed to the fourth hour of the scotophase. The mean time of calling per day decreased significantly with the number of days since first calling, and the mean number of calling bouts increased with days since first calling.
Choice of Female Groups by Male Mosquitofish (Gambusia holbrooki)
Authors: Agrillo Christian , Dadda Marco , Serena Giovanna 
Published: April 2008

AbstractEven though females are usually more selective in choosing their mates, males are also capable of exercising mate choice. Despite the large body of evidence on the individual features preferred in sexual selection, little attention has been devoted to the first stage of male–female interaction. As poeciliid fish are known to be social, in the wild, initially mate choice may concern a preliminary selection among shoals. Only after this primary choice, males may subsequently direct their attention to a specific mate. We observed spontaneous preference of male mosquitofish (Gambusia holbrooki) when choosing between groups differing in size and sex ratio. In partial agreement with our predictions, males preferred to join a group of females rather than an isolated one (expt 1) and the larger group when two female groups were presented (expt 2). An all‐female group was preferred to a mixed‐sex group (expt 3), whereas no preference was observed when the two mixed‐sex groups differed in the number of males (expt 4) or in the size of the males (expt 5). These results suggest that male mosquitofish are capable of discriminating among different quantities of individuals within a group and use such information to select among groups in order to optimize the likelihood of successful matings.
The influence of ants on soil and water losses from an orange orchard in eastern Spain
Authors: Cerdà A. , Jurgensen M. F. 
Published: April 2008

AbstractHerbicide applications have greatly reduced plant cover, and increased soil erosion on a new orange orchard planted on valley slopes in eastern Spain. This has increased the importance of soil fauna, such as ants, in regulating soil erosion processes. Ants increase water infiltration rates by forming soil macropores during nest construction, but new soil brought to the surface by ant activity could increase the sediments available for erosion. Simulated rainfall experiments were conducted on 20 paired plots (20 with ant activity and 20 controls) to study the impact of ants on surface water flow and sediment movement in an intensively managed orange orchard near Valencia, Spain. Simulated rainfall was applied to each plot at a rate of 55 mm/h on a 0.25 m2area for 1 h. We found a reduction of soil bulk density, an increase in soil organic matter, and an increase in macropore flow in ant‐affected soils, as compared to soil without ant activity. These ant‐induced soil changes increased water infiltration rates and runoff discharge. However, the fresh, unconsolidated soil brought to the surface during nest construction resulted in greater soil loss on two plots than their ant‐free controls. Ants can be an important factor in soil erosion processes when surface vegetation is removed by intensive herbicide use.
The impact of ants on mineral soil properties and processes at different spatial scales
Authors: Cammeraat E. L. H. , Risch A. C. 
Published: April 2008

AbstractSoil dwelling ants are important soil engineers that have a large impact on the soil ecosystem. This is reflected in the alteration of soil properties by ants due to burrowing activities, the accumulation of organic matter and other nutrients in the soil, which, in turn, alters soil physical, chemical and (micro) biological processes. A review of recent literature on these fine scale soil changes resulting from ant activity is presented in this paper. However, ants do not only affect soil properties at the fine scale but also have effects at the hillslope and catchment scales with respect to surface hydrological processes and ecosystem functioning.At the finest scale, most studies showed changed soil textures, lowered bulk densities and increased infiltration where ant burrows or mineral mounds are prominent. Only a few studies investigated the effects of ants on soil properties such as soil structure and aggregate stability, which were improved by ant activity. Nutrients were generally considered to be concentrated in nests, and increased nutrient cycling involving microbial processes were reported. On a broader scale, the information on nest densities and patterns is crucial to understand the impacts of ants, but this information is scarcely available. It has been reported that the activity of ants increases the heterogeneity of soil infiltration rates and nutrient concentrations at the landscape scale, which in turn has consequences for the redistribution of sediments and nutrients by geomorphological and biotic processes.A hierarchical descriptive model focusing on dry land ecosystems is presented to incorporate small‐scale ant activity into broader scale hillslope and catchment processes. However, this model has to be tested and more research is needed, especially on these broader scale aspects, to be able to fully understand the role of ants on the ecosystem and landscape scale.
Influence of the wood ant,Formica polyctena,on soil nutrient and the spruce tree growth
Authors: Frouz J. , Rybníček M. , Cudlín P. , Chmelíková E. 
Published: April 2008

AbstractThe effect ofFormica polyctenaant nests on the distribution of soil nutrients, soil pH and the growth of Norway spruce trees was studied in the southern part of the Czech Republic. Soil nutrient content (exchangeable P, N, K and pH) and growth of mature spruce trees were measured at four distances from the nearest ant hill (0–1, 3–5, 10–50 and >200 m). Trees at all distances were visited by ants, except for those >200 m from the nearest nest. Soil pH and of P, K and NO3concentrations were higher near ant nests (<1 m), and pH and K at distances of 3–5 m, when compared with distances of 10–50 and >200 m from the nests, where no significant differences in these variables were detected. In contrast, tree ring analyses (1974–2004) showed that trees >200 m from the ant nests grew significantly faster than trees at other distances, followed by trees within 1 m of the nests. No growth differences were found between the growth of trees at 3–5 and 10–50 m from ant nests. We postulate that nutrient and carbohydrate removal of honeydew collected by ant‐tended aphids are slowing growth of tree. However, trees may partly compensate for this depletion by having access to a larger supply of soil nutrients near ant nests.
Detection of HBV core promoter and precore mutations helps distinguish flares of chronic hepatitis from acute hepatitis B
Authors: Kusumoto Koichiro , Yatsuhashi Hiroshi , Nakao Rumiko , Hamada Rumiko , Fukuda Mika , Tamada Yoko , Taura Naota , Komori Atsumasa , Daikoku Manabu , Hamasaki Keisuke , Nakao Kazuhiko , Ishibashi Hiromi , Miyakawa Yuzo , Eguchi Katsumi 
Published: April 2008

AbstractBackground and Aim:  Acute exacerbation of chronic hepatitis B has to be distinguished from acute hepatitis, because treatment strategies differ between them.Methods:  Mutations in the core promoter and precore region of hepatitis B virus (HBV) were determined in 36 patients with acute exacerbation of chronic hepatitis B, in whom alanine aminotransferase (ALT) increased above 500 IU/L, as well as the 36 patients with acute hepatitis.Results:  Mutations in the core promoter (A1762T/G1764A) and precore region (G1896A) were more frequent in patients with acute exacerbation of chronic hepatitis than acute hepatitis (81% vs 19%; P < 0.0001 and 58% vs 6%; P < 0.0001, respectively). Of the 19 patients with mutations in both the core promoter and precore region, 17 (89%) had acute exacerbation of chronic hepatitis. In contrast, among the 32 patients with the wild‐type for both the core promoter and precore region, 29 (89%) developed acute hepatitis. By multivariate analysis, the double mutation in the core promoter was predictive of acute exacerbation in chronic hepatitis with the highest odds ratio at 26.4.Conclusions:  In patients with hepatitis B having ALT levels >500 IU/L, mutations in the core promoter and precore region are useful in distinguishing acute exacerbation of chronic from acute HBV infection. Detection of these mutations would be useful for commencing prompt antiviral treatments on patients with acute exacerbation of chronic hepatitis for a better prognosis.
Randomised comparison of the FerX Ella antireflux stent and the ultraflex stent: Proton pump inhibitor combination for prevention of post‐stent reflux in patients with esophageal carcinoma involving the esophago‐gastric junction
Authors: Sabharwal Tarun , Gulati Manpreet S , Fotiadis Nikolas , Dourado Renato , Botha Abrie , Mason Robert , Adam Andreas 
Published: April 2008

AbstractBackground and Aim:  Metal stents placed across the gastroesophageal junction in patients with malignant dysphagia frequently present with reflux symptoms. We compared an antireflux stent with a standard open stent used in combination with proton pump inhibitor medication.Methods:  Forty‐nine patients with dysphagia due to inoperable carcinoma in the lower third of the esophagus were randomly selected to receive either a antireflux valve stent (FerX‐Ella) (n = 22) or a covered standard open stent (Ultraflex), which was combined with proton pump inhibitors such as omeprazole (n = 26). The technical success, the presence of reflux, and complications were recorded.Results:  Reflux was seen in 3/22 patients (13.6%) in the FerX‐Ella group and in 2/26 patients (7.7%) in the Ultraflex and proton pump inhibitor combination group (P‐value not significant). In both groups, a significant improvement in the dysphagia score was seen and no statistically significant difference was detected between the two groups (P = 0.84). The FerX‐Ella stents migrated more frequently (32%) than the Ultraflex stents (23%). This also necessitated surgical intervention more frequently in the FerX‐Ella group (2/22, 9.1%) compared to the Ultraflex group (1/26, 3.8%).Conclusion:  The antireflux stent had no demonstrable advantages compared to the combination of standard open stent and proton pump inhibitor medication.
End of life in the intensive care unit: knowledge and practice of clinicians from Karachi, Pakistan
Authors: Salahuddin N. , Shafqat S. , Mapara S. , Khan S. , Siddiqui S. , Manasia R. , Ahmad A. 
Published: April 2008

AbstractBackground:  With improvements in the care of critically ill, physicians are faced with obligations to provide quality end‐of‐life care. Barriers to this include inadequate understanding of the dying patient and withdrawal or limitation of care. The objectives of this study were to document the comprehensions of physicians and nurses regarding the recognition and practice of end‐of‐life care for critically ill patients placed on life support in the intensive care unit.Methods:  This was a cross‐sectional study carried out at three hospitals in Karachi. Chi‐squared analysis and one‐way anova were used to compare differences in response between the groups.Results:  One hundred and thirty‐seven physicians and critical care nurses completed the survey. ‘Brain death’ was defined as an ‘irreversible cessation of brainstem function’ by 85% respondents, with 50% relying on specialty consultation. Withdrawal of life support is practised by 83.2%; physicians are more likely (Chi square test P‐value < 0.001) to withdraw mechanical ventilation, compared with nurses who would withdraw vasopressors (P‐value 0.006). In a do not resuscitate patient, 72.3% use vasopressors, 83% initiate haemodialysis and 17.5% use non‐invasive ventilation; 72.6% consult Hospital Ethics Committees; 16% respondents never withdraw life support; 28.3% considered it their responsibility to ‘sustain life at all costs’ and only 8% gave religious beliefs as a reason.Conclusions:  There are confusions in the definition of brain death, end‐of‐life recognition and indications and processes of withdrawal of life support. There are discrepancies between physicians’ and nurses’ perceptions and attitudes. Clearly, teaching programmes will need to incorporate cultural and religious differences in their ethics curricula.
Glucose control during acute myocardial infarction
Authors: Cheung N. W. 
Published: April 2008

AbstractThe need for tight glycaemic control in the immediate aftermath of myocardial infarction is controversial. Trials of glucose–insulin–potassium (GIK) therapy, given without regard to glucose levels, have only confused the issue. Despite considerable clinical interest, only three randomized controlled trials have, as their primary goal, aimed to determine whether better glycaemic control improves the outcomes of myocardial infarction. This review examines the results of these trials and other data to support the case for tight glycaemic control in patients with myocardial infarction.
Ecological consequences of genetic diversity
Authors: Hughes A. Randall , Inouye Brian D. , Johnson Marc T. J. , Underwood Nora , Vellend Mark 
Published: April 2008

AbstractUnderstanding the ecological consequences of biodiversity is a fundamental challenge. Research on a key component of biodiversity, genetic diversity, has traditionally focused on its importance in evolutionary processes, but classical studies in evolutionary biology, agronomy and conservation biology indicate that genetic diversity might also have important ecological effects. Our review of the literature reveals significant effects of genetic diversity on ecological processes such as primary productivity, population recovery from disturbance, interspecific competition, community structure, and fluxes of energy and nutrients. Thus, genetic diversity can have important ecological consequences at the population, community and ecosystem levels, and in some cases the effects are comparable in magnitude to the effects of species diversity. However, it is not clear how widely these results apply in nature, as studies to date have been biased towards manipulations of plant clonal diversity, and little is known about the relative importance of genetic diversity vs. other factors that influence ecological processes of interest. Future studies should focus not only on documenting the presence of genetic diversity effects but also on identifying underlying mechanisms and predicting when such effects are likely to occur in nature.