bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variability in factors causing light attenuation in Lake Victoria
Authors: LOISELLE STEVEN A. , AZZA NICHOLAS , CÓZAR ANDRES , BRACCHINI LUCA , TOGNAZZI ANTONIO , DATTILO ARDUINO , ROSSI CLAUDIO 
Published: January 2008

Summary1. The major optical components controlling the attenuation of photosynthetic available radiation in nearshore areas of Lake Victoria (Uganda and Kenya) were examined and their impact compared. It was found that chromophoric dissolved organic matter and tripton play a dominating role in many nearshore areas, indicating that the coastal areas of Lake Victoria cannot be considered as Case I waters.2. Concentrations of chromophoric dissolved organic matter declined with distance from the coast in an exponential manner indicating dilution and degradation of terrestrial sources of organic matter rather than in situ production. The importance of tripton was found to follow a similar pattern, while the relative importance of phytoplankton biomass in overall attenuation of photosynthetic available radiation was found to increase with distance from the coast. A specific attenuation coefficient for phytoplankton biomass was determined (0.019 m2 mg Chl a−1).3. Using a light limitation approach based on carrying capacity, it was possible to map areas that are closer to being light limited. Light limitation appears to occur throughout most bays and some coastal areas receiving catchment waters. This spatial information, geographically referenced to bathymetric and catchment conditions, was utilized to understand the importance of environmental conditions in limiting phytoplankton biomass.
Invertebrate traits for the biomonitoring of large European rivers: an assessment of specific types of human impact
Authors: DOLÉDEC SYLVAIN , STATZNER BERNHARD 
Published: January 2008

Summary1. The power of selected biological invertebrate traits for discriminating different types of human impact (heavy metal pollution and cargo‐ship traffic) were tested using ecological reasoning and linear Discriminant Function Analysis (DFA).2. Frequency distributions of individual traits and categories of traits from 68 least impacted river reaches (LIRRs) and 304 impacted river reaches were used to define simple assessment rules based on ecological reasoning for specific impairments in large European rivers. In calibration, a maximum of three variables with a priori predictions and two different impairment threshold levels were used. Similarly, DFA was performed on the same variables included in the ecological reasoning approach, but also on all available traits or trait categories.3. Validation with an independent data set (40 LIRRs, 291 variously impacted river reaches) and using the ecological reasoning approach showed that 75–78% of the reaches were correctly assign with rules on all impact types, 35–57% with rules on heavy metal pollution and 78–93% with rules on cargo‐ship traffic. By comparison, validation showed that DFA performed globally poorer than the ecological reasoning approach. In addition, the performance of the rules based on ecological reasoning remained stable, whereas DFA performance changed between calibration and validation.4. Although not defined for this purpose, our study provided alarming evidence regarding the impact of cargo‐ship traffic on invertebrate communities in river reaches. Reaches with cargo‐ship traffic were found to have more genera with long life cycles that reproduce repeatedly by ovoviviparity and have a sessile life.5. The performance of our trait‐based approach to correctly assign reaches to either least impacted or impacted conditions should promote further research on the topic across larger geographic areas (without regionalization) and across smaller stream types to provide a powerful biomonitoring tool that fulfils current European Union directives.
To sink or float: the fate of dormant offspring is determined by maternal behaviour in Daphnia
Authors: ŚLUSARCZYK MIROSŁAW , PIETRZAK BARBARA 
Published: January 2008

Summary

As the ephippia (chitinous shells enclosing diapausing eggs) of pelagic crustaceans of the genus Daphnia have been occasionally reported to float at the water surface, we considered that this might be an adaptation promoting their passive dispersal. We investigated the mechanisms by which ephippia appear at the water surface.
While field surveys revealed that floating Daphnia ephippia are often numerous in various freshwater habitats, laboratory tests showed that newly formed ephippia are not buoyant initially. Once transferred to the surface by whatever means, however, they may remain there due either to surface tension or gas absorption.
Video recordings showed that all ephippia at the water surface in laboratory vessels were shed there by ephippial females when moulting (despite the attendant risk of exposure to UV radiation). This implies that the moulting behaviour of female Daphnia may determine the fate of their dormant offspring, predetermining whether they remain in the natal environment (when the ephippium is released into the water column) or disperse (when it is deposited at the water surface).
Our findings reveal a potential mechanism underlying the high dispersal capacity of freshwater cladocerans inhabiting island‐like aquatic habitats.
Identifying and quantifying uncertainty and spatial disagreement in the comparison of Global Land Cover for different applications
Authors: FRITZ STEFFEN , SEE LINDA 
Published: January 2008

AbstractThis paper provides a methodology for comparing global land cover maps that allows for differences in legend definitions between products to be taken into account. The legends of the two maps are first reconciled by creating a legend lookup table that shows how the legends map onto one another. Where there is overlap, the specific definitions for each legend class are used to calculate the degree of overlap between legend classes. In this way, one‐to‐many mappings are accounted for unlike in most methods where the legend definitions are often forced into place. Another advantage over previous map comparison methods is that application‐specific requirements are captured using expert input, whereby the user rates the importance of disagreement between different legend classes based on the needs of the application. This user‐defined matrix in conjunction with the degree of overlap between legend classes is applied on a pixel‐by‐pixel basis to create maps of spatial disagreement and uncertainty. The user can then highlight the areas of highest thematic uncertainty and disagreement between the different land cover maps allowing for areas that require further detailed examination to be readily identified. It would also be possible for several users to input their knowledge into the process, leading to a potentially more robust comparison of land cover products. The methodology of map comparison is illustrated using different land cover products including Global Land Cover 2000 (GLC‐2000) and the MODIS land cover data set. Two diverse applications are provided including the estimation of global forest cover and monitoring of agricultural land. In the case of global forest cover, an example was provided for Columbia, which showed that the MODIS land cover map overestimates forest cover in comparison with the GLC‐2000. The agricultural example, on the other hand, served to illustrate that for Sudan, MODIS tends to underestimate crop areas while GLC‐2000 overestimates them.
Determination of the relative avidity of the specific IgG antibodies in human toxocariasis
Authors: DZIEMIAN E. , ŻARNOWSKA H. , KOŁODZIEJ‐SOBOCIŃSKA M. , MACHNICKA B. 
Published: January 2008

SUMMARY Human toxocariasis is a zoonosis caused by infection with larvae of the ascarid nematode Toxocara canis and, less frequently, T. cati. Our study developed a method for distinguishing distant from recent human toxocariasis by assessing the avidity of the IgG antibodies. The avidity of specific antibodies increases with time after antigen challenge and assessment of the degree of avidity can be used to discriminate between recent and distant infections. The relative avidity was measured in 150 sera from children with visceral toxocariasis and in 46 sera from children with ocular toxocariasis. The probable time of infection was estimated on the basis of the medical history and clinical syndrome. Our study showed that 94·2% of positive sera collected from patients reporting infection > 6 months ago had high IgG avidity values, confirming distant toxocariasis, whereas 25·9% of positive sera taken < 6 months after infection showed low indices of IgG avidity. Our results suggest that measurement of the specific IgG avidity may assist in discriminating between recent and distant toxocariasis. The method can be used effectively to rule out (because of high avidity) a recently acquired infection. Low avidity is less reliable in discriminating between recent and distant infections.
Evidence for Pleistocene wet aeolian dune and interdune accumulation, S. Pedro da Maceda, north‐west Portugal
Authors: GRANJA HELENA M. , DTE GROOT THOMAS A. M. , COSTA ANA L. 
Published: January 2008

AbstractOutcrops and cored/counter‐flushed boreholes in the coastal area between Espinho and Aveiro (north‐west Portugal) were investigated to reconstruct the changing patterns of sedimentation during the Late Pleistocene–Holocene. To obtain a common comparison basis, the grain‐size data from outcrop and borehole samples were analysed. The outcrops and the cored parts of the boreholes were dated by radiocarbon and optically stimulated luminescence. The results show that, on top of pebble‐rich beds of fluvial origin, a wet aeolian dune and interdune environment was active during the later part of the Pleistocene, turning to dry aeolian at the transition to the Holocene. The data indicate also that aeolian accumulation was controlled by vegetation changes (climate) and groundwater table fluctuations. During the Holocene, a podzol formed on the Pleistocene dunes and extensive vegetation precluded major aeolian accumulations. Remobilization of sand started again because of human deforestation and – last but not least – the Little Ice Age.
Phytochrome‐mediated inhibition of shade avoidance involves degradation of growth‐promoting bHLH transcription factors
Authors: Lorrain Séverine , Allen Trudie , Duek Paula D. , Whitelam Garry C. , Fankhauser Christian 
Published: January 2008

SummaryPlant growth and development are particularly sensitive to changes in the light environment and especially to vegetational shading. The shade‐avoidance response is mainly controlled by the phytochrome photoreceptors. In Arabidopsis, recent studies have identified several related bHLH class transcription factors (PIF, for phytochrome‐interacting factors) as important components in phytochrome signaling. In addition to a related bHLH domain, most of the PIFs contain an active phytochrome binding (APB) domain that mediates their interaction with light‐activated phytochrome B (phyB). Here we show that PIF4 and PIF5 act early in the phytochrome signaling pathways to promote the shade‐avoidance response. PIF4 and PIF5 accumulate to high levels in the dark, are selectively degraded in response to red light, and remain at high levels under shade‐mimicking conditions. Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light‐activated phyB. Our data suggest that, in dense vegetation, which is rich in far‐red light, shade avoidance is triggered, at least partially, as a consequence of reduced phytochrome‐mediated degradation of transcription factors such as PIF4 and PIF5. Consistent with this idea, the constitutive shade‐avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5.
Mycotic keratitis: an overview of diagnosis and therapy
Authors: Shukla P. K. , Kumar M. , Keshava G. B. S. 
Published: January 2008

SummaryThe increased incidence of fungal infections in the recent past has been attributed to the increase in the number of human immunodeficiency virus‐positive and AIDS patients. Early diagnosis of mycoses in patients is crucial for prompt antifungal therapy. The yield of clinical examination in the diagnosis of keratomycosis is 63–83% and KOH mount is 91%. This still highlights the limitation of routine clinical examination and smear examination, which is not performing 100% efficiently. It is for these 37%, 17% and 9% of cases, every day advanced technologies are called for. Those who deal with patient care are aware of certainties and uncertainties of results of clinical examination. The best reported figures at specialized centres might not translate into clinical practice. Another factor to be kept in mind is that many patients who come after secondary and tertiary referrals are already treated with antibiotics, antivirals, steroids and sometimes even antifungals that distort the clinical picture completely. Further, one has to consider as well the cases caused by yeast‐like fungi, which resemble bacterial keratitis. Confirmation of diagnosis, not only in case of mycotic keratitis but also for other diseases, to initiate prompt and accurate therapy would avoid unnecessary and indiscriminate use of steroids/antibacterials/antivirals and antifungals.
Expression of a fungal ferulic acid esterase increases cell wall digestibility of tall fescue (Festuca arundinacea)
Authors: Buanafina Marcia M. de O. , Langdon Tim , Hauck Barbara , Dalton Sue , Morris Phillip 
Published: January 2008

SummaryIn the cell walls of forage grasses, ferulic acid is esterified to arabinoxylans and participates with lignin monomers in oxidative coupling pathways to generate ferulate–polysaccharide–lignin complexes that cross‐link the cell wall. Such cross‐links hinder cell wall degradation by ruminant microbes, reducing plant digestibility. In this study, genetically modified Festuca arundinacea plants were produced expressing an Aspergillus niger ferulic acid esterase (FAEA) targeted to the vacuole. The rice actin promoter proved to be effective for FAEA expression, as did the cauliflower mosaic virus (CaMV) 35S and maize ubiquitin promoters. Higher levels of expression were, however, found with inducible heat‐shock and senescence promoters. Following cell death and subsequent incubation, vacuole‐targeted FAEA resulted in the release of both monomeric and dimeric ferulic acids from the cell walls, and this was enhanced several fold by the addition of exogenous endo‐1,4‐β‐xylanase. Most of the FAEA‐expressing plants showed increased digestibility and reduced levels of cell wall esterified phenolics relative to non‐transformed plants. It is concluded that targeted FAEA expression is an effective strategy for improving wall digestibility in Festuca and, potentially, other grass species used for fodder or cellulosic ethanol production.
Delayed combinatorial treatment with flavopiridol and minocycline provides longer term protection for neuronal soma but not dendrites following global ischemia
Authors: Iyirhiaro Grace O. , Brust Tyson B. , Rashidian Juliet , Galehdar Zohreh , Osman Aweis , Phillips Maryam , Slack Ruth S. , MacVicar Brian A. , Park David S. 
Published: January 2008

AbstractWe previously reported that delayed administration of the general cyclin‐dependent kinase inhibitor flavopiridol following global ischemia provided transient neuroprotection and improved behavioral performance. However, it failed to provide longer term protection. In the present study, we investigate the ability of delayed flavopiridol in combination with delayed minocycline, another neuroprotectant to provide sustained protection following global ischemia. We report that a delayed combinatorial treatment of flavopiridol and minocycline provides synergistic protection both 2 and 10 weeks following ischemia. However, protected neurons in the hippocampal CA1 are synaptically impaired as assessed by electrophysio logical field potential recordings. This is likely because of the presence of degenerated processes in the CA1 even with combinatorial therapy. This indicates that while we have addressed one important pre‐clinical parameter by dramatically improving long‐term neuronal survival with delayed combinatorial therapy, the issue of synaptic preservation of protected neurons still exists. These results also highlight the important observation that protection does not always lead to proper function.
Rapid, stimulation‐induced reduction of C12‐resorufin in motor nerve terminals: linkage to mitochondrial metabolism
Authors: Talbot Janet D. , Barrett John N. , Barrett Ellen F. , David Gavriel 
Published: January 2008

AbstractThe Alamar blue (resazurin) assay of cell viability monitors the irreversible reduction of non‐fluorescent resazurin to fluorescent resorufin. This study focused on the reversible reduction of C12‐resorufin to non‐fluorescent C12‐dihydroresorufin in motor nerve terminals innervating lizard intercostal muscles. Resting C12‐resorufin fluorescence decreased when the activity of the mitochondrial electron transport chain (ETC) was accelerated with carbonyl cyanide m‐chloro phenyl hydrazone, and increased when ETC activity was inhibited with cyanide. Trains of action potentials (50 Hz for 20–50 s), which reversibly decreased NADH fluorescence and partially depolarized the mitochondrial membrane potential, produced a reversible decrease in C12‐resorufin fluorescence which had a similar time course. The stimulation‐induced decrease in C12‐resorufin fluorescence was blocked by inhibitors of ETC complexes I, III, and IV and by carbonyl cyanide m‐chloro phenyl hydrazone, but not by inhibiting mitochondrial ATP synthesis with oligomycin. Mitochondrial depolarization and the decreases in C12‐resorufin and NADH fluorescence depended on Ca2+ influx into the terminal, but not on vesicular transmitter release. These results suggest that the reversible reduction of C12‐resorufin in stimulated motor nerve terminals is linked, directly or indirectly, to the reversible oxidation of NADH and to Ca2+ influx into mitochondria, and provides an assay for rapid changes in motor terminal metabolism.
Expression and comparative characterization of Gq‐coupled invertebrate visual pigments and melanopsin
Authors: Terakita Akihisa , Tsukamoto Hisao , Koyanagi Mitsumasa , Sugahara Michio , Yamashita Takahiro , Shichida Yoshinori 
Published: January 2008

AbstractA non‐visual pigment melanopsin, which is localized in photosensitive retinal ganglion cells and is involved in the circadian photoentrainment and pupillary responses in mammals, is phylogenetically close to the visual pigments of invertebrates, such as insects and cephalopods. Recent studies suggested that melanopsin is a bistable pigment and drives a Gq‐mediated signal transduction cascade, like the invertebrate visual pigments. Because detailed electrophysiological properties are somewhat different between the visual cells and the photosensitive ganglion cells, we here expressed and purified the invertebrate visual pigment and melanopsin to comparatively investigate their Gq‐activation abilities. We successfully expressed and purified UV and blue light‐sensitive visual pigments of the honeybee as well as the amphioxus melanopsin. Although the purified UV‐sensitive pigment and the melanopsin lost their bistable nature during purification, reconstitution of the pigments in lipid vesicles resulted in return of the bistable nature. The light‐dependent Gq‐activation abilities among these reconstituted pigments are similar, suggesting that the electrophysiological differences do not depend on the Gq‐activation step but rather on the other signal transduction steps and/or on cell properties. Our findings are also important in that this is the first report describes a heterologous large‐scale expression of the Gq‐coupled invertebrate visual pigments in cultured cells.
Differential regulation of c‐Jun N‐terminal kinase and NF‐κB pathway by caffeic acid phenethyl ester in astroglial and monocytic cells
Authors: Choi Kyungsun , Choi Chulhee 
Published: January 2008

AbstractCaffeic acid phenethyl ester (CAPE), an active component of propolis extracts, has been known for its specific inhibition of nuclear factor κB (NF‐κB) and subsequent anti‐inflammatory activity. In this study, we report that (i) CAPE exerts its anti‐inflammatory action (inhibition of tumor necrosis factor‐induced expression of intercellular adhesion molecule‐1 and CC chemokine ligand‐2) via NF‐κB inhibition by two distinct molecular mechanisms in a cell‐specific manner: CAPE inhibited downstream pathways of inhibitor κB (IκB) degradation in monocytic cells, while activation of upstream IκB kinase was suppressed by CAPE pre‐treatment in astroglial cells; and (ii) CAPE paradoxically activates the c‐Jun N‐terminal kinase (JNK) pathway, which might be responsible for its pro‐apoptotic action and divergent regulation of proinflammatory mediators such as CXC chemokine ligand‐8.
The GSK3 hypothesis of Alzheimer’s disease
Authors: Hooper Claudie , Killick Richard , Lovestone Simon 
Published: January 2008

J. Neurochem. (2008) 104, 1433–1439.AbstractGlycogen synthase kinase 3 (GSK3) is a constitutively active, proline‐directed serine/threonine kinase that plays a part in a number of physiological processes ranging from glycogen metabolism to gene transcription. GSK3 also plays a pivotal and central role in the pathogenesis of both sporadic and familial forms of Alzheimer’s disease (AD), an observation that has led us to coin the ‘GSK3 hypothesis of AD’. According to this hypothesis, over‐activity of GSK3 accounts for memory impairment, tau hyper‐phosphorylation, increased β‐amyloid production and local plaque‐associated microglial‐mediated inflammatory responses; all of which are hallmark characteristics of AD. If our ‘GSK3 hypothesis of AD’ is substantiated and GSK3 is indeed a causal mediator of AD then inhibitors of GSK3 would provide a novel avenue for therapeutic intervention in this devastating disorder.
HIV‐infected macrophages mediate neuronal apoptosis through mitochondrial glutaminase
Authors: Tian Changhai , Erdmann Nathan , Zhao Jianxing , Cao Zhijun , Peng Hui , Zheng Jialin 
Published: January 2008

AbstractA significant number of patients infected with human immunodeficiency virus‐1 (HIV‐1) suffer cognitive impairment ranging from mild to severe HIV‐associated dementia (HAD), a result of neuronal degeneration in the basal ganglia, cerebral cortex and hippocampus. Mononuclear phagocyte dysfunction is thought to play an important role in the pathogenesis of HAD. Glutamate neurotoxicity is triggered primarily by massive Ca2+ influx arising from over‐stimulation of the NMDA subtype of glutamate receptors. The underlying mechanisms, however, remain elusive. We have tested the hypothesis that mitochondrial glutaminase in HIV‐infected macrophages is involved in converting glutamine to glutamate. Our results demonstrate that the concentration of glutamate in HIV‐1 infected conditioned media was dependent on glutamine dose, and HIV‐1 infected conditioned medium mediated glutamine‐dependent neurotoxicity. These results indicate HIV‐infection mediates neurotoxicity through glutamate production. In addition, glutamate‐mediated neurotoxicity correlated with caspase activation and neuronal cell cycle re‐activation. Inhibition of mitochondrial glutaminase diminished the HIV‐induced glutamate production, and attenuated NMDA over‐stimulation and subsequent neuronal apoptosis. These data implicate mitochondrial glutaminase in the induction of glutamate‐mediated neuronal apoptosis during HIV‐associated dementia, and provides a possible therapeutic strategy for HAD treatment.