bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conducting the initiation of protein synthesis: the role of eIF4G
Authors: Prévôt Déborah , Darlix Jean‐Luc , Ohlmann Théophile 
Published: May 2003

AbstractThe eukaryotic initiation factor eIF4G is a large modular protein which serves as a docking site for initiation factors and proteins involved in RNA translation. Together with eIF4E and eIF4A, eIF4G constitutes the eIF4F complex which is a key component in promoting ribosome binding to the mRNA. Thus, the central role of eIF4G in initiation makes it a valid target for events aimed at modulating translation. Such events occur during viral infection by picornaviruses and lentiviruses and result in the hijack of the translational machinery through cleavage of eIF4G. Proteolysis of eIF4G is also mediated by caspases during the onset of apoptosis causing inhibition of protein synthesis. We will review the role of eIF4G and protein partners as well as the cellular and viral events that modulate eIF4G activity in the initiation of translation.
On two-dimensional hamiltonian transport equations with Llocp coefficients
Authors: Hauray M 
Published: May 2003

We consider two-dimensional autonomous divergence free vector-fields in Lloc2. Under a condition on direction of the flow and on the set of critical points, we prove the existence and uniqueness of a stable a.e. flow and of renormalized solutions of the associated transport equation.

Résumé
On considère ici des champs de vecteurs à divergence nulle et à coefficients dans Lloc2. Avec une condition locale sur la direction du champ de vecteur, on prouve l’existence et l’unicité d’un flot presque partout et des solutions renormalisées de l’équation de transport associée.
Association analysis of the insertion/deletion polymorphism in serotonin transporter gene in patients with affective disorder
Authors: Hauser Joanna , Leszczyńska Anna , Samochowiec Jerzy , Czerski Piotr M. , Ostapowicz Agata , Chlopocka Maria , Horodnicki Jan , Rybakowski Janusz K. 
Published: May 2003

AbstractA polymorphism of serotonin transporter was studied in 226 patients with affective disorders (n = 132 for bipolar, n = 94 for unipolar affective disorder) and in 213 healthy subjects. Consensus diagnosis by at least two psychiatrists, according to the ICD-10 and DSM-IV criteria was made for each patient using SCID (Structured Clinical Interview for DSM-IV Axis I Disorders). A functional polymorphism in the promoter region of serotonin transporter gene, where 44 bp are either inserted (long allele) or deleted (short allele) was analysed. Genotype s/s was significantly more frequent in patients comparing to the control group (P = 0.011 for bipolar and P = 0.003 for unipolar affective disorder) - the most marked association was found in males with bipolar and unipolar illness. The allele frequencies also differ significantly between patients and controls (P = 0.003 for bipolar and P = 0.001 for unipolar affective disorder). The frequency of the low activity (short) allele was higher in patients than in controls (51.1% in bipolar, and 54.3 in unipolar vs 39.4% in controls). We suggest that the presence of allele s may increase the susceptibility to occurrence of affective disorder.
The role of limbic and cortical regions in schizophrenia: Focus on dopamine
Authors: Marchese G. , Pani L. 
Published: May 2003

SummaryDopamine is implicated in the pathogenesis of both the positive and the negative symptoms of schizophrenia. Clinical efficacy of antipsychotic drugs, without the production of side-effects, may be achieved by a dose–response separation of pharmacological function, regional (i.e., anatomical) selectivity of action, or by the selective targeting of neuroreceptors. The atypical antipsychotics have many different ways of acting on receptors in the brain, but they have in common a decreased likelihood of producing extrapyramidal side-effects. Patients respond well to them by showing improvements of both positive and negative symptoms. The preclinical profile of amisulpride shows specificity for D2/D3 dopamine receptors and selective activity in the limbic system. There is evidence that amisulpride is effective in treating both the negative and positive symptoms of schizophrenia, and that it has a low propensity to induce motor side-effects. Therefore, both positive and negative symptoms can be treated, without inducing these side-effects, by selectively targeting dopamine receptors.
Cytoskeletons in prokaryotes
Authors: Mayer F 
Published: May 2003

AbstractNot only eukaryotes, but also prokaryotes possess a cytoskeleton. Tubulin‐related bacterial protein FtsZ, and actin‐related bacterial proteins MreB/Mbl have recently been described as constituents of bacterial cytoskeletons. Genes coding for MreB/Mbl could only be found in elongated bacteria, not in coccoid forms. It was speculated that constituents of today's eukaryotic cytoskeleton (tubulin, actin) may have evolved from prokaryotic precursor proteins closely related to today's bacterial proteins FtsZ and MreB/Mbl.Prior to the description of proteins MreB/Mbl, evidence had been obtained for the existence of a shape‐preserving cytoskeleton ubiquitously present in all bacteria. In the meantime, structural studies allow to speculate on a possible role of bacterial elongation factor Tu (EF‐Tu) as a structural element in such a “cytoskeletal web”. EF‐Tu was long known to form fibrillar structures in vitro; now experimental data accumulate, pointing towards formation of intracellular protofilaments containing EF‐Tu, and networks thereof as well. In addition, results of these structural studies suggest a so far unknown mode of complex formation of EF‐Tu with active ribosomes: ribosomes/polysomes were seen to be attached to intracellular protofilaments. Implications for the understanding of EF‐Tu—ribosome interaction, and a role of such a kind of putative protofilaments as a general site of attachment for cellular functional macromolecules are discussed. The notion is discussed that an EF‐Tu‐containing cytoskeletal web might have been the “primary” or “basic” kind of prokaryotic cytoskeleton, already in existence prior to the “invention” of precursors of today's MreB.
Investigation of megakaryocyte apoptosis in children with acute and chronic idiopathic thrombocytopenic purpura
Authors: Uçar Canan , Ören Hale , I˙rken Gülersu , Ateş Halil , Atabay Berna , Türker Meral , Vergin Canan , Yaprak Işın 
Published: May 2003

Abstract: Objective: Although the platelet destruction shows a primary role in the thrombocytopenia of idiopathic thrombocytopenic purpura (ITP), it has been demonstrated that impaired platelet production may also contribute to the severity of thrombocytopenia in ITP. The present study examined megakaryocyte apoptosis in bone marrow aspirates of children with acute and chronic ITP and investigated the role of megakaryocyte apoptosis in ITP pathophysiology.Methods: Thirteen children diagnosed with acute ITP and eight children diagnosed with chronic ITP comprised the study group. Ten children, who were hospitalized for scoliosis operation but healthy otherwise, comprised the control group. In all children, megakaryocytes were isolated from the same amount of bone marrow aspirate samples using MACS CD61 MicroBeads (Miltenyl Biotec, Auburn, CA, USA). Megakaryocyte apoptosis was studied with transferase‐mediated d‐UTP‐bitin nick end‐labeling method.Results: Isolated megakaryocyte counts did not differ significantly between acute ITP, chronic ITP and control groups. The percentage of apoptotic megakaryocytes did not differ significantly between acute ITP group and control group and between chronic ITP group and control group. The percentage of apoptotic megakaryocytes in patients with chronic ITP was significantly lower than the patients with acute ITP. There was no correlation between the percentage of apoptotic megakaryocytes and platelet counts of the cases.Conclusions: Increased megakaryocytic apoptosis does not play a role in the pathogenesis of dysmegakaryopoiesis and impaired platelet production in children with ITP. Decreased megakaryocyte apoptosis in cases with chronic ITP may be due to suppression of megakaryocyte maturation, as the terminal phase of the megakaryocyte lifespan is characterized by the onset of apoptosis.
Sequence variation in the bovine and ovine PRNP genes
Authors: Hills D. , Schlaepfer J. , Comincini S. , MacLean I. , Dolf G. , Ferretti L. , Olsaker I. , Williams J. L. 
Published: May 2003

SummaryA resequencing approach was adopted to identify sequence variants in the PRNP gene that may affect susceptibility or resistance to bovine spongiform encephalopathy. The entire PRNP gene (>21 kb) was sequenced from 26 chromosomes from a group of Holstein‐Friesian cows, as well as exon 3 of PRNP (>4 kb) from a further 24 chromosomes from six diverse breeds. We identified 51 variant sequences of which 42 were single nucleotide polymorphisms and nine were insertion/deletion (indel) events. The study was extended to exon 3 of the sheep PRNP gene where 23 sequence variants were observed, four of which were indels. The level of nucleotide diversity in the complete bovine PRNP gene was π = 0.00079, which is similar to that found at the bovine T‐cell receptor alpha delta joining region (π = 0.00077), but somewhat less than that observed for the bovine leptin (π = 0.00265). Sequence variation within exon 3 of PRNP in both cattle (π = 0.00102) and sheep (π = 0.00171) was greater than that for the complete PRNP gene, with sheep showing greater sequence variation in exon 3 than cattle. The level of sequence variation reported here is greater than previously thought for the bovine PRNP gene in cattle. This study highlights the contribution that recombination plays in increasing allelic diversity in this species.
Deletion of one of the duplicated Hsp70 genes causes hereditary myopathy of diaphragmatic muscles in Holstein‐Friesian cattle
Authors: Sugimoto M. , Furuoka H. , Sugimoto Y. 
Published: May 2003

SummaryHeat‐shock protein 70 (Hsp70) is a major chaperone that folds protein and prevents aggregation. The Hsp70 family contains both constitutive and stress‐inducible forms. In humans, two of the inducible Hsp70 genes are located within the human major histocompatibility complex (MHC) on 6p21.3, as a duplicated locus, 12 kb apart from each other. We report that loss of one of the duplicated Hsp70 genes, the bovine homologue within the bovine MHC, is responsible for hereditary myopathy of diaphragmatic muscles (HMDM) in Holstein‐Friesian cattle. Although the remaining Hsp70 gene is intact, Hsp70 protein levels are dramatically decreased in affected cattle. In normal diaphragmatic muscle, Hsp70 binds several proteins involved in energy metabolism including glycogen phosphorylase (PYGM). Immunohistochemical staining indicated that PYGM accumulated in the HMDM‐specific core‐like structures in affected cattle. Misfolding of energy‐related proteins due to Hsp70 deficiency might lead to protein aggregation and muscle fibre degeneration.
Mean residence time of soil organic matter associated with kaolinite and smectite
Authors: Wattel‐ Koekkoek E. J. W. , Buurman P. , Van Der Plicht J. , Wattel E. , Van Breemen N. 
Published: May 2003

SummaryTo gain insight into the effect of clay mineralogy on the turnover of organic matter, we analysed the 14C activity of soil organic matter associated with clay in soils dominated by kaolinite and smectite in natural savanna systems in seven countries. Assuming that carbon inputs and outputs are in equilibrium in such soils, we took the 14C age as mean residence time of the organic matter. We corrected the 14C activity for the Suess effect, Bomb effect and difference between date of sampling and date of 14C measurement. Organic matter associated with kaolinite turned over fast (360 years on average). Organic matter associated with smectite turned over relatively slowly, with an average mean residence time for the whole clay‐size fraction of 1100 years. Multiple linear regression indicates that clay mineralogy is the main factor explaining differences in the mean residence time of the organic matter extracted.
Characteristics of dissolved organic matter and phenolic compounds in forest soils under silver birch (Betula pendula), Norway spruce (Picea abies) and Scots pine (Pinus sylvestris)
Authors: Suominen K. , Kitunen V. , Smolander A. 
Published: May 2003

SummaryThe aim was to characterize dissolved organic matter in soils under different tree species. Molecular size distribution and chemical composition of dissolved organic carbon and nitrogen were determined in water extracts from humus layers and mineral soils taken from silver birch (Betula pendula Roth.), Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) stands. Concentrations of tannins and 15 phenolic acids in the humus layers were measured. Per unit of organic matter, the concentrations of dissolved organic C and N were larger in birch and spruce humus layers than in the pine humus layer. In the underlying mineral soil, the concentrations of dissolved organic C were similar at all sites, but the concentration of dissolved organic N was greater in spruce and pine soils than in birch soil. In all soils, the 10–100 kDa fraction was the most abundant molecular size group and hydrophobic acids the most abundant chemical group of dissolved organic C. In all humus layers, hydrophobic acids and hydrophilic bases were the major components of dissolved organic N. There were only minor differences in the concentrations of total tannins in the humus layers under different tree species. Small‐molecule tannins (about < 0.5 kDa) were most abundant in the birch humus, and large‐molecule tannins in the pine humus. Coniferous humus contained more ferulic and p‐coumaric acids than did the birch humus. The concentrations of 3,4 and 3,5‐dihydroxybenzoic acid, vanillic acid and 4‐hydroxybenzoic acid were similar in all soils.
Short‐term transformations of lead and cadmium compounds in soil after contamination
Authors: Bataillard P. , Cambier P. , Picot C. 
Published: May 2003

SummaryThe behaviour and fate of trace metals, in particular lead and cadmium, when they contaminate the soil as atmospheric fall‐out are not well understood. To improve our understanding, we incorporated pure compounds of lead and cadmium into samples taken from surface horizons of three chemically contrasting soils and monitored the changes in their speciation by analysing the soil solution. In most instances the concentrations of trace metals in solution were maximal during the first few days after mixing the contaminants with the soil, and depended strongly on soil type. The exception was when the contaminant was added as sulphide particles. The initial speciation of metals also influenced their solubility, following a decreasing order which did not depend on the soil type:
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Lead sulphide was progressively oxidized, but cadmium sulphide was hardly dissolved. When lead was added as sulphate, between 10 and 20% of lead particles dissolved, regardless of the soil type. For the other species, dissolution was enhanced at lower soil pH. Thermodynamic calculations with the WinHumic V program indicated that the solution was not saturated with respect to lead sulphate. We conclude that dissolution must be limited by the adsorption of inhibitors on reactive surfaces. The calculations also showed that precipitation of chloropyromorphite probably controls lead concentration in leachate from the acid organic soil. Finally, both soil type and initial speciation of contaminants control the behaviour of trace metals in soils for a time greater than a cropping season and must be considered for understanding their environmental impact.
Interaction of copper and zinc with allophane and organic matter in the B horizon of an Andosol
Authors: Latrille C. , Denaix L. , Lamy I. 
Published: May 2003

SummaryAndosols developed on basaltic material are naturally rich in metals. Organic matter and allophane, the key colloids of these soils, have a strong affinity for trace metals, but are intimately mixed so that speciation of trace metal is difficult to determine. We used three complementary approaches, namely physical fractionation, chemical extraction and potentiometric measurement, to distinguish them. Physical particle‐size separations and chemical selective dissolution of allophanes and organic matter were combined to demonstrate relations between the occurrence of colloids and contents of Cu and Zn in an andic B horizon. About 22% of total soil Cu and 7% of total soil Zn were present in the < 5‐μm fraction, associated with organic or amorphous mineral constituents. To support this association further, the affinity of soil colloids for Cu and Zn in a mimicked system was demonstrated. An Al‐rich allophane was synthesized, and a portion of the organic matter was extracted from the clay fraction, and their reactivities towards Cu2+or Zn2+were studied by potentiometry. The two metallic cations displayed specific affinity towards allophane or soluble organic matter. Furthermore, the behaviour of copper and zinc in the ternary system, allophane + soluble organic matter + trace element, revealed a synergy in the surface complexation. The use of these three speciation approaches highlighted the linkage between metals and constituents, and showed how important the colloidal constituents are in the behaviour of Cu and Zn in Andosols.
Mineral surfaces and soil organic matter
Authors: Kaiser K. , Guggenberger G. 
Published: May 2003

SummaryThe organic carbon content of soil is positively related to the specific surface area (SSA), but large amounts of organic matter in soil result in reduced SSA as determined by applying the Brunauer–Emmett–Teller (BET) equation to the adsorption of N2. To elucidate some of the controlling mechanisms of this relation, we determined the SSA and the enthalpy of N2 adsorption of separates with a density > 1.6 g cm−3 from 196 mineral horizons of forest soils before and after removal of organic matter with NaOCl. Likewise, we investigated these characteristics before and after sorption of increasing amounts of organic matter to four mineral soil samples, oxides (amorphous Al(OH)3, gibbsite, ferrihydrite, goethite, haematite), and phyllosilicates (kaolinite, illite).Sorption of organic matter reduced the SSA, depending on the amount sorbed and the type of mineral. The reduction in SSA decreased at larger organic matter loadings. The SSA of the mineral soils was positively related to the content of Fe oxyhydroxides and negatively related to the content of organic C. The strong reduction in SSA at small loadings was due primarily to the decrease in the micropores to which N2 was accessible. This suggests preferential sorption of organic matter at reactive sites in or at the mouths of micropores during the initial sorption and attachment to less reactive sites at increasing loadings. The exponential decrease of the heat of gas adsorption with the surface loading points also to a filling or clogging of micropores at early stages of organic matter accumulation. Desorption induced a small recovery of the total SSA but not of the micropore surface area.Destruction of organic matter increased the SSA of all soil samples. The SSA of the uncovered mineral matrix related strongly to the amounts of Fe oxyhydroxides and the clay. Normalized to C removed, the increase in SSA was small in topsoils and illuvial horizons of Podzols rich in C and large for the subsoils containing little C. This suggests that micropores preferentially associate with organic matter, especially at small loadings. The coverage of the surface of the soil mineral matrix as calculated from the SSA before and after destruction of organic matter was correlated only with depth, and the relation appeared to be linear.We conclude that mineralogy is the primary control of the relation between surface area and sorption of organic matter within same soil compartments (i.e. horizons). But at the scale of complete profiles, the surface accumulation and stabilization of organic matter is additionally determined by its input.
A comparison of randomized intervention analysis and two‐factor analysis of variance for analysis of angler effort in a floodplain river fishery
Authors: Cloutman D. G. , Jackson D. C. 
Published: May 2003

AbstractProbability values were compared among randomized intervention analysis (RIA) and untransformed and loge‐transformed two‐factor analyses of variance (anova) to test effects of fish stocking and a public relations programme on angler effort. The data set consisted of a time series of angler vehicle counts at single control and impact locations in a before–after‐control‐impact (BACI) experimental design. A randomized complete block anova indicated that probability values from RIA and the untransformed and loge‐transformed two‐factor anova did not differ significantly (P = 0.345), and that they did not result in different conclusions concerning angler effort. Randomized intervention analysis is superior to two‐factor anova in not having to conform with assumptions of parametric statistics, and it tests for temporal autocorrelation. Two‐factor anova is superior to RIA in providing statistical inferences about possible differences in main effects, i.e. control and impact locations and pre‐ and post‐treatment periods, if the interaction term is non‐significant. To achieve the most comprehensive analysis, it is recommended that both RIA and two‐factor anova (whether untransformed or transformed) be performed during field experiments of angler effort when using a BACI design at single control and treatment locations.