julilili42/papers huggingface dataset:
Pesticide and pathogen: Heat shock protein expression and acetylcholinesterase inhibition in juvenile Chinook salmon in response to multiple stressors
2007-05-14

Abstract Rapid expression of heat shock protein (hsp) families in response to a variety of stressors has been demonstrated in many organisms, including fish. The present 60-d challenge study was designed to compare hsp induction in juvenile Chinook salmon following exposure to individual pesticides, virus, and both stressors combined. Heat shock protein expression patterns over time were monitored and related to the extent of virus infection and mortality. Acetylcholinesterase (AChE) inhibition and recovery in response to applied stressors were measured in brain. High enzyme inhibition levels have been correlated with imminent mortality, and other sublethal physiological effects have been observed in fish concurrent with depressed AChE activity. Mortality was elevated considerably in fish exposed to 0.08 μg/L of the pyrethroid esfenvalerate (EV). Mortality due to infectious hematopoietic necrosis virus (IHNV) was lower in groups previously treated with pesticides; however, these fish died sooner than individuals exposed to virus only. Both pesticides, EV and the organophosphate (OP) chlorpyrifos (CP), as well as virus exposure, induced hsp expression, but highest hsp levels were observed after the combined treatments, suggesting an additive effect between virus and pesticides. Highest virus titers were accompanied by strongest hsp induction, indicating a connection between virus concentration and hsp expression. In conclusion, the measurement of hsp expression appears to be a very sensitive, integrative indicator of stress. Esfenvalerate and IHNV did not affect AChE activity, and exposure to 3.7 μg/L CP led to significantly inhibited AChE for at least 20 d. The time required for complete recovery of AChE activity raises concern about deleterious behavioral effects.
Interaction of the GraRS Two-Component System with the VraFG ABC Transporter To Support Vancomycin-Intermediate Resistance in Staphylococcus aureus
2007-05-15

ABSTRACT Current treatment for serious infections caused by methicillin-resistant Staphylococcus aureus relies heavily upon the glycopeptide antibiotic vancomycin. Unfortunately, this practice has led to an intermediate resistance phenotype that is particularly difficult to treat in invasive staphylococcal diseases, such as septicemia and its metastatic complications, including endocarditis. Although the vancomycin-intermediate resistance phenotype has been linked to abnormal cell wall structures and autolytic rates, the corresponding genetic changes have not been fully elucidated. Previously, whole-genome array studies listed numerous genes that are overexpressed in vancomycin-intermediate sensitive strains, including graRS (SACOL0716 to -0717), encoding a two-component regulatory system (TCRS), as well as the adjacent vraFG (SACOL0718 to -0720), encoding an ATP-binding cassette (ABC) transporter; but the exact contribution of these genes to increased vancomycin resistance has not been defined. In this study, we showed that isogenic strains with mutations in genes encoding the GraRS TCRS and the VraFG ABC transporter are hypersensitive to vancomycin as well as polymyxin B. Moreover, GraRS regulates the expression of the adjacent VraFG pump, reminiscent of gram-positive bacteriocin-immunity regulons. Mutations of graRS and vraFG also led to increased autolytic rates and a more negative net surface charge, which may explain, in part, to their increased sensitivity to cationic antimicrobial peptides. Taken together, these data reveal an important genetic mediator to the vancomycin-intermediate S. aureus phenotype and may hold clues to the selective pressures on staphylococci upon exposure to selective cationic peptide antibiotics used in clinical practice.
Das Symbolum Quicumque als Kompilation augustinischer Tradition
2007-05-15

Abstract The article aims to analyse the origin of the so-called Athanasianum or Symbolum Quicumque. The text, whose extraordinary reception from the 8 th century onwards is clear from the various manuscripts and commentaries of this time, has to be dated before the first reference to it in 670 (or perhaps even before 630). For establishing the terminus post quem, a detailed analysis of the verbal parallels in Augustine and the various authors of the 5 th and 6 th century has been done again. This leads to the conclusion that the text is for the most part a compilation of verbal quotes of Augustine and Augustinian theologians. Especially those authors who tried to ‘compress’ the trinitarian and christological theology of Augustine as Vincentius, Fulgentius and even Caesarius, are used, nearly no expression of the text cannot be found in these Augustinian traditions. As Caesarius (even Sermo 10) does not seem to be the first witness of the Symbolum Quicumque, but one of its sources, even the famous prologue of the manuscript of Zwiefalten is not originally by Caesarius, but uses the Caesarian-Augustinian tradition stating that the prologue is written by Augustine himself. The manuscript shows clearly the purpose of the compilation, i.e. the aim to establish an Augustinian “standard level” for the clergy. So the text is not only a reception of Augustine, but in the same instance an important multiplication of this Augustinian tradition. This is a very useful example for describing the focus of a modern “Dogmengeschichte” – searching for the concepts and theological thoughts that were not only conditioned by, but even shaping the cultural frame-work and the Christian identity (or identities) of their time.
Detection of VHE gamma-ray emission from the distant blazar 1ES 1101-232 with HESSand broadband characterisation
2007-05-16

The blazar 1ES 1101-232 was observed with the High Energy Stereoscopic System\\n(H.E.S.S.) of Atmospheric Cherenkov Telescopes (ACT) in 2004 and 2005, for a\\nlive time of 43 hours. VHE (E &gt; 10^11 eV) gamma-rays were detected for the\\nfirst time from this object. VHE observations of blazars are used to\\ninvestigate the inner parts of the blazar jets, and also to study the\\nextragalactic background light (EBL) in the near-infrared band. Observations in\\n2005 were conducted in a multiwavelength campaign, together with the RXTE\\nsatellite and optical observations. In 2004, simultaneous observations with\\nXMM-Newton were obtained. 1ES 1101-232 was detected with H.E.S.S. with an\\nexcess of 649 photons, at a significance of 10 sigma. The measured VHE\\ngamma-ray flux amounts to dN/dE = (5.63 +- 0.89) x 10^-13 (E/TeV)^-(2.94 +-\\n0.20) cm^-2 s^-1 TeV^-1, above a spectral energy threshold of 225 GeV. No\\nsignificant variation of the VHE gamma-ray flux on any time scale was found.\\n1ES 1101-232 exhibits a very hard spectrum, and at a redshift of z=0.186, is\\nthe blazar with the highest confirmed redshift detected in VHE gamma-rays so\\nfar. The data allow the construction of truly simultaneous spectral energy\\ndistributions of the source, from the optical to the VHE band. Using an EBL\\nmodel with \\\\nu F_\\\\nu = 14 nW m^-2 sr^-1 at 1.5 \\\\mu m as presented in Aharonian\\net al. (Nature, 2006, 440, 1018) suggests an intrinsic VHE power output peak of\\nthe source at above 3 TeV.\\n
Measurement of Decoherence of Electron Waves and Visualization of the Quantum-Classical Transition
2007-05-16

Controlled decoherence of free electrons due to Coulomb interaction with a truly macroscopic environment, the electron (and phonon) gas inside a semiconducting plate, is studied experimentally. The quantitative results are compared with different theoretical models. The experiment confirms the main features of the theory of decoherence and can be interpreted in terms of which-path information. In contrast to previous model experiments on decoherence, the obtained interferograms directly visualize the transition from quantum to classical.
Collisions between equal-sized ice grain agglomerates
2007-05-16

\\n Context.Following the recent insight in the material structure of comets,\\nprotoplanetesimals are assumed to have low densities and to be highly\\nporous agglomerates. It is still unclear if planetesimals can be formed\\nfrom these objects by collisional growth.\\n Aims.Therefore, it is important to study numerically the\\n collisional outcome from low velocity impacts of equal sized\\n porous agglomerates which are too large to be examined in a laboratory experiment.\\n Methods.We use the Lagrangian particle method Smooth Particle Hydrodynamics to\\nsolve the equations that describe the dynamics of\\nelastic and plastic bodies. Additionally, to account for the influence\\nof porosity, we follow a previous developed equation of state and\\ncertain relations between the material strength and the relative\\ndensity.\\n Results.Collisional growth seems possible for rather low collision velocities\\nand particular material strengths. The remnants of collisions with\\nimpact parameters that are larger than 50% of the radius of the\\ncolliding objects tend to rotate. For small impact parameters, the\\ncolliding objects are effectively slowed down without a prominent\\ncompaction of the porous structure, which probably increases the\\npossibility for growth. The protoplanetesimals, however, do not stick\\ntogether for the most part of the employed material strengths.\\n Conclusions.An important issue in subsequent studies has to be the influence of\\n rotation to collisional growth. Moreover, for realistic\\n simulations of protoplanetesimals it is crucial to know the\\n correct material parameters in more detail.\\n
XMM-Newton observations of HESS J1813-178 reveal a composite Supernova remnant
2007-05-16

Aims.We present X-ray and 12CO(J=1-0) observations of the very-high-energy (VHE) -ray source HESS J1813-178 with the aim of understanding the origin of the -ray emission.&#13;\\nMethods. High-angular resolution X-ray studies of the VHE -ray emission region are performed using 18.6 ks of XMM-Newton data, taken on HESS J1813-178 in October 2005. Using this data set we are able to undertake spectral and morphological studies of the X-ray emission from this object with greater precision than previous studies. NANTEN 12CO(J=1-0) data are used to search for correlations of the -ray emission with molecular clouds which could act as target material for -ray production in a hadronic scenario.&#13;\\nResults.The NANTEN 12CO(J=1-0) observations show a giant molecular cloud of mass at a distance of 4 kpc in the vicinity of HESS J1813-178. Even though there is no direct positional coincidence, this giant cloud may have influenced the evolution of the -ray source and its surroundings. The X-ray data show a highly absorbed ( cm-2) non-thermal X-ray emitting object coincident with the previously known ASCA source AX J1813-178 exhibiting a compact core and an extended tail towards the north-east, located in the centre of the radio shell-type Supernova remnant (SNR) G12.82-0.02 . This central object shows morphological and spectral resemblance to a Pulsar Wind Nebula (PWN) and we therefore consider that this object is very likely to be a composite SNR. We discuss the scenario in which the -rays originate in the shell of the SNR, and that in which they originate in the central object, in terms of a time-dependent one-zone leptonic model. We demonstrate, that in order to connect the core X-ray emission to the VHE -ray emission electrons have to be accelerated to energies of at least 1 PeV.
3.0 Tesla High Spatial Resolution Contrast-Enhanced Magnetic Resonance Angiography (CE-MRA) of the Pulmonary Circulation
2007-05-16

The described 3 T CE-MRA protocol in addition to high T1 relaxivity of Gd-BOPTA provides sufficient SNR to support highly accelerated parallel acquisition (GRAPPA x 6), resulting in acquisition of isotopic (1 x 1 x 1 mm3) voxels over the entire pulmonary circulation in 20 seconds.
Sugar for My Honey: Carbohydrate Partitioning in Ectomycorrhizal Symbiosis
2007-05-16

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Pluractional Adverbials
2007-05-17

This paper investigates the semantics of adverbials like ‘page by page’ and ‘stone upon stone’. An analysis is developed in which sentences containing such adverbials have a pluractional semantics; that is, pluralization affects simultaneously the event- and the individual-argument slot of a predicate. Sternefeld's (1998) system of plural operators is used and extended for this purpose. The adverbial constrains the relation that is pluralized and makes visible a higher plural operator. In the case of ‘page by page’-type adverbials, this is a fairly standard operator that leads to a simple divisional interpretation. In the case of ‘stone upon stone’-type adverbials, the operator has a stronger semantics that leads to a sequence interpretation. The generality of our theory permits straightforward extension to data like ‘she ran and ran’ and ‘she climbed higher and higher’, among others. Finally we propose that inclusive alternative ordering reciprocals (Dalrymple et al. 1998) have a pluractional sequence interpretation as well.
The crystal structure of the secreted aspartic proteinase 3 from Candida albicans and its complex with pepstatin A
2007-05-17

Abstract The family of secreted aspartic proteinases (Sap) encoded by 10 SAP genes is an important virulence factor during Candida albicans (C. albicans) infections. Antagonists to Saps could be envisioned to help prevent or treat candidosis in immunocompromised patients. The knowledge of several Sap structures is crucial for inhibitor design; only the structure of Sap2 is known. We report the 1.9 and 2.2 Å resolution X‐ray crystal structures of Sap3 in a stable complex with pepstatin A and in the absence of an inhibitor, shedding further light on the enzyme inhibitor binding. Inhibitor binding causes active site closure by the movement of a flap segment. Comparison of the structures of Sap3 and Sap2 identifies elements responsible for the specificity of each isoenzyme. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Cholinergic Modulation of Sevoflurane Potency in Cortical and Spinal Networks In Vitro
2007-05-17

Background Victims of organophosphate intoxication with cholinergic crisis may have need for sedation and anesthesia, but little is known about how anesthetics work in these patients. Recent studies suggest that cholinergic stimulation impairs gamma-aminobutyric acid type A (GABAA) receptor function. Because GABAA receptors are major targets of general anesthetics, the authors investigated interactions between acetylcholine and sevoflurane in spinal and cortical networks. Methods Cultured spinal and cortical tissue slices were obtained from embryonic and newborn mice. Drug effects were assessed by extracellular voltage recordings of spontaneous action potential activity. Results Sevoflurane caused a concentration-dependent decrease in spontaneous action potential firing in spinal (EC50=0.17+/-0.02 mM) and cortical (EC50=0.29+/-0.01 mM) slices. Acetylcholine elevated neuronal excitation in both preparations and diminished the potency of sevoflurane in reducing action potential firing in cortical but not in spinal slices. This brain region-specific decrease in sevoflurane potency was mimicked by the specific GABAA receptor antagonist bicuculline, suggesting that (1) GABAA receptors are major molecular targets for sevoflurane in the cortex but not in the spinal cord and (2) acetylcholine impairs the efficacy of GABAA receptor-mediated inhibition. The latter hypothesis was supported by the finding that acetylcholine reduced the potency of etomidate in depressing cortical and spinal neurons. Conclusions The authors raise the question whether cholinergic overstimulation decreases the efficacy of GABAA receptor function in patients with organophosphate intoxication, thereby compromising anesthetic effects that are mediated predominantly via these receptors such as sedation and hypnosis.
THE EVOLUTIONARY HISTORY OF MYCORRHIZAL SPECIFICITY AMONG LADY'S SLIPPER ORCHIDS
2007-05-18

Although coevolution is acknowledged to occur in nature, coevolutionary patterns in symbioses not involving species-to-species relationships are poorly understood. Mycorrhizal plants are thought to be too generalist to coevolve with their symbiotic fungi; yet some plants, including some orchids, exhibit strikingly narrow mycorrhizal specificity. Here, we assess the evolutionary history of mycorrhizal specificity in the lady's slipper orchid genus, Cypripedium. We sampled 90 populations of 15 taxa across three continents, using DNA methods to identify fungal symbionts and quantify mycorrhizal specificity. We assessed phylogenetic relationships among sampled Cypripedium taxa, onto which we mapped mycorrhizal specificity. Cypripedium taxa associated almost exclusively with fungi within family Tulasnellaceae. Ancestral specificity appears to have been narrow, followed by a broadening after the divergence of C. debile. Specificity then narrowed, resulting in strikingly narrow specificity in most of the taxa in this study, with no taxon rewidening to the same extant as basal members of the genus. Sympatric taxa generally associated with different sets of fungi, and most clades of Cypripedium-mycorrhizal fungi were found throughout much of the northern hemisphere, suggesting that these evolutionary patterns in specificity are not the result of biogeographic lack of opportunity to associate with potential partners. Mycorrhizal specificity in genus Cypripedium appears to be an evolvable trait, and associations with particular fungi are phylogenetically conserved.
Contribution of the N-acetyltransferase 2 polymorphism NAT2*6A to age-related hearing impairment
2007-05-18

Background: Age-related hearing impairment (ARHI) is the most common sensory impairment in older people, affecting 50% of those aged 80 years. The proportion of older people is increasing in the general population, and as a consequence, the number of people affected with ARHI is growing. ARHI is a complex disorder, with both environmental and genetic factors contributing to the disease. The first studies to elucidate these genetic factors were recently performed, resulting in the identification of the first two susceptibility genes for ARHI, NAT2 and KCNQ4 . Methods: In the present study, the association between ARHI and polymorphisms in genes that contribute to the defence against reactive oxygen species, including GSTT1 , GSTM1 and NAT2 , was tested. Samples originated from seven different countries and were combined into two test population samples, the general European population and the Finnish population. Two distinct phenotypes for ARHI were studied, Z low and Z high , representing hearing in the low and high frequencies, respectively. Statistical analysis was performed for single polymorphisms ( GSTM1 , GSTT1 , NAT2*5A , NAT2*6A , and NAT2*7A ), haplotypes, and gene–environment and gene–gene interactions. Results: We found an association between ARHI and GSTT1 and GSTM1 in the Finnish population sample, and with NAT2*6A in the general European population sample. The latter finding replicates previously published data. Conclusion: As replication is considered the ultimate proof of true associations in the study of complex disorders, this study provides further support for the involvement of NAT2*6A in ARHI.
Ultrathin transition-metal oxide films: Thickness dependence of the electronic structure and local geometry in MnO
2007-05-18

Ultrathin manganese monoxide films on silver substrates are studied as a function of the thickness using x-ray absorption spectroscopy and x-ray photoemission spectroscopy. By combining these techniques, an improved understanding of both the local geometry and the electronic structure is achieved. It was found that both electronic and geometric properties in ultrathin films differ significantly from the bulk. A tetragonal distortion of the oxide films is revealed by polarization-dependent x-ray absorption measurements; the extent is decreasing gradually with increasing film thickness. A relaxation of an epitaxial oxide layer induced by heating also leads to a decrease of the tetragonal interface strain. The electronic structure of ultrathin manganese oxide films changes in the valence-band region with dependence on thickness.
Detection and management of alcohol use disorders in German primary care influenced by non-clinical factors
2007-05-18

There is a clear need to increase the special diagnostic and therapeutic skills of general practitioners so that they may be able to indicate and perform secondary prevention. Further research should focus on the likely effects of the implementation of these diagnostic and management tools.
Microsatellite Instability and Compromized Mismatch Repair Gene Expression During In Vitro Passaging of Monoclonal Human T Lymphocytes
2007-05-19

An age-related accumulation of DNA damage caused by increased insult and/or decreased repair, could contribute to impaired cellular function. DNA mismatch repair (MMR), the main postreplicative correction pathway, can be monitored by assessing microsatellite instability and has been reported to decrease with age. Here, we analyzed the involvement of the MMR system in the accumulation of genetic damage in a cultured monoclonal human T lymphocyte model. We correlated microsatellite instability (MSI) and MMR gene expression, and replicative senescence of CD4 + clones derived from young, old and centenarian individuals or from CD34 + precursors. Cells were analyzed for MSI at five loci (CD4, VWA, Fes, D2S123, and BAT26), for the methylation status of MLH1 and MSH2 gene promoters, and for the expression of the MMR genes MSH2, MSH6, MSH3, MLH1, PMS2, and PMS1. MSI increased with increasing culture passages, particularly in the CD34 + progenitor-derived clones, but also in those from adult T cells. MSI and MMR gene expression were found to correlate, mostly due to a reduced expression of the components of MutL heterodimers, pointing to a role of MMR in the acquisition of DNA damage with in vitro aging.
Global gene expression in Ha‐ras and B‐raf mutated mouse liver tumors
2007-05-19

Abstract Chemically‐induced mouse liver tumors harbor mutations in different oncogenes. About 50% of tumors contain activating mutations in the Ha‐ras gene contain and about 20% of tumors show point mutations in the B‐raf oncogene. We have investigated the gene expression profiles in tumors of the 2 genotypes by microarray analysis. In total, ∼500 genes or expressed sequences were aberrantly expressed in tumors relative to normal liver tissue. Around two/thirds of them were significantly altered in both Ha‐ras and B‐raf mutated liver tumors, and most of the remaining genes showed at least qualitatively comparable changes in both tumor types. Several functional clusters were hypothesized in tumors of the 2 genotypes which involve alterations in a battery of genes encoding enzymes of lipid metabolism. The similarity in the patterns of global gene expression of Ha‐ras and B‐raf mutated liver tumors suggests that mutational activation of the 2 oncogenes results in activation of a common set of transcriptional regulators. © 2007 Wiley‐Liss, Inc.