bluuebunny/crossref_metadata_2025 huggingface dataset:
Zielorientierung und Bezugsnormorientierung: Zum Zusammenhang zweier Konzepte
Authors: Schöne Claudia , Dickhäuser Oliver , Spinath Birgit , Stiensmeier-Pelster Joachim
Published: July 2004

Zusammenfassung: Zielorientierungen und Bezugsnormorientierungen sind zwei innerhalb der Pädagogischen Psychologie ausgesprochen fruchtbare Konstrukte, die sich sowohl aufgrund ihrer Entstehung als auch ihrer konkreten Inhalte deutlich unterscheiden. Dennoch werden beide Konstrukte argumentativ häufig miteinander in Beziehung gebracht, ohne dass bis heute eine empirische Überprüfung dieser Beziehung erfolgte. In der vorliegenden Untersuchung überprüfen wir die Annahme, dass Personen solche Bezugsnormen bevorzugen, die zu Informationen über das Erreichen der von ihnen verfolgten Ziele führen. Eine Lernzielorientierung sollte mit einer individuellen Bezugsnormorientierung einhergehen, eine Leistungszielorientierung dagegen mit einer sozialen Bezugsnormorientierung. In sechs Studien wurden die beiden Konstrukte per Fragebogen in verschiedenen Stichproben (Studierende, Elftklässler, Siebt-/Achtklässler, Viertklässler sowie Eltern) erhoben. Die Befunde stützen die Hypothesen. Implikationen der Befunde für die zugrunde liegenden Theorien werden diskutiert.
Zeitpunkte
Authors: Ash Mitchell G.
Published: July 2004

Zusammenfassung. Der Text ist eine geringfügig überarbeitete Fassung des Festvortrags, gehalten im Rahmen der Jubiläumsveranstaltung “100 Jahre Deutsche Gesellschaft für Psychologie, ehemals Gesellschaft für experimentelle Psychologie“ an der Justus-Liebig-Universität Gießen am 4. April 2004. Der Beitrag beginnt mit allgemeinen Bemerkungen über die Entstehung und wechselnden Funktionen wissenschaftlicher Tagungen und Kongresse in der neueren Geschichte. Der Autor nähert sich dann der Geschichte der DGPs durch eine knappe Analyse der Inhalte ausgewählter Kongresse der Gesellschaft; dabei stehen sowohl zentrale Ereignisse in der Geschichte der Gesellschaft als auch Wendepunkte der deutschen Geschichte im Mittelpunkt der Betrachtung.
Source and Qp parameters from pulse width inversion of microearthquake data in southeastern Sicily, Italy
Authors: de Lorenzo Salvatore , Di Grazia Giuseppe , Giampiccolo Elisabetta , Gresta Stefano , Langer Horst , Tusa Giuseppina , Ursino Andrea
Published: July 2004

Source and Qp parameters were estimated from the inversion of first arrival P waveform durations of about 300 microearthquakes recorded at a digital seismic network operating in southeastern Sicily. The average risetime and pulse width at each station do not show large differences, allowing us to exclude significant differential attenuation site effects. A first Qp estimate was obtained by applying the classical risetime method, under the assumption of a point‐like source time function. In order to investigate the effect of directivity due to the finiteness of seismic sources, new nonlinear relationships, based on a circular crack model rupturing at a constant velocity, were numerically built. These relationships were used to formulate a nonlinear inverse method for retrieving source (radius, dip, and strike of the circular crack) and Qp parameters from the inversion of risetime and pulse width data. The application of the method produced a better fit of the observed data and a Qp value higher than that obtained by applying the risetime method. The discrepancy between the different Q estimates may be due to a trade‐off among source dimension and Qp, as we inferred from a test on a subset of low‐magnitude events (Ml ≤ 2.5). A good agreement with independent estimates of fault plane solutions, as inferred from P polarities and S polarizations, was found. The estimated stress drops are generally very low (0.1–10 bars). This suggests that the background seismic activity in southeastern Sicily is related to fault segments and/or weakened zones where great stress accumulations are hindered.
Evidence of midmantle anisotropy from shear wave splitting and the influence of shear‐coupled P waves
Authors: Wookey J. , Kendall J.‐M.
Published: July 2004

Until recently, the midmantle region of the Earth (the transition zone and the uppermost lower mantle) has been considered isotropic. Recent work by Wookey et al. [2002] presented evidence of anisotropy in the midmantle region near the Tonga‐Kermadec subduction zone, inferred from shear wave splitting in teleseismic S phases at Australian seismic stations. This data set is revisited to examine the possibility of contamination by shear‐coupled P waves. Using reflectivity modeling, we explore the effects of these phases on the measurement of shear wave splitting. Contamination of such measurements is demonstrated for short epicentral distances (Δ ∼ 30°). Wave field decomposition is a simple technique which can be used to separate these phases from the main S wave arrival. The Tonga‐Australia data set is reprocessed after wave field decomposition. Shear wave splitting ranging between 0.7 and 6.2 s is observed, a range comparable to that observed by Wookey et al. [2002]. As before, the polarization of the fast shear wave is observed to be predominantly horizontal. However, the magnitudes of splitting for several events at short epicentral distances are significantly reduced, suggesting some influence of shear‐coupled P waves in the original analysis. The results are compared with possible models of mantle anisotropy, and the results can be best explained by significant anisotropy in the midmantle region. The best candidate location for this anisotropy is in the uppermost lower mantle, and scenarios involving the alignment of lower mantle or subducted materials by regional dynamic processes are suggested to account for this.
Generation of metastable oxygen atom O(1D) in sprite halos
Authors: Hiraki Y. , Tong L. , Fukunishi H. , Nanbu K. , Kasai Y. , Ichimura A.
Published: July 2004

We propose a nighttime source of metastable oxygen atoms O(1D) in the mesosphere. Here O(1D) atoms are generated by electron impact dissociation of O2 molecules in sprite halo events, where electrons are accelerated in strong electric fields associated with lightning discharges. The peak production rate of O(1D) in a single sprite halo event is estimated to be as large as 104 cm−3 for a duration of 1 ms, which is comparable to, or even larger than, the steady rate by solar‐UV radiation. We also discuss the altitude dependence of O(1D) production in sprite halos and the dependence on day and night.
Attempting to bridge the gap between laboratory and seismic estimates of fracture energy
Authors: McGarr A. , Fletcher J. B. , Beeler N. M.
Published: July 2004

To investigate the behavior of the fracture energy associated with expanding the rupture zone of an earthquake, we have used the results of a large‐scale, biaxial stick‐slip friction experiment to set the parameters of an equivalent dynamic rupture model. This model is determined by matching the fault slip, the static stress drop and the apparent stress. After confirming that the fracture energy associated with this model earthquake is in reasonable agreement with corresponding laboratory values, we can use it to determine fracture energies for earthquakes as functions of stress drop, rupture velocity and fault slip. If we take account of the state of stress at seismogenic depths, the model extrapolation to larger fault slips yields fracture energies that agree with independent estimates by others based on dynamic rupture models for large earthquakes. For fixed stress drop and rupture speed, the fracture energy scales linearly with fault slip.
Anomalous magmatic degassing prior to the 5th April 2003 paroxysm on Stromboli
Authors: Aiuppa A. , Federico C.
Published: July 2004

A major explosion occurred at Stromboli on April 5 2003, being the most powerful event over a period of exceptional eruptive activity lasting from December to July. Here, we describe results from a network of diffusive tubes set up on the Stromboli's summit area, aimed at a characterisation of plume composition (SO2, HCl, HF) prior to and after April 5. Data analysis revealed anomalous sulphur degassing 2–3 days before the event, when SO2/HCl ratios (≈9) significantly higher than those typical of quiescent degassing (≈1) were recorded. We interpret this exceptional plume signature as an evidence of S‐rich magmas ascending in the shallow plumbing system, and propose high SO2/HCl as a potential precursor of major explosions on the volcano. The post‐April 5 phase was characterised by time‐decreasing SO2/HCl and SO2/HF plume ratios, ascribed to declining magma feeding as a prelude to restoration of “normal” Strombolian activity.
Influence of long‐range‐transported pollution on the annual and diurnal cycles of carbon monoxide and ozone at Cheeka Peak Observatory
Authors: Weiss‐Penzias Peter , Jaffe Daniel A. , Jaeglé Lyatt , Liang Qing
Published: July 2004

We assess the importance of distant pollution sources on the marine background by combining measurements of carbon monoxide (CO) and ozone (O3) with model simulations from the GEOS‐CHEM chemical transport model and two types of back trajectories. Measurements were made over a complete annual cycle from March 2001 to May 2002 at Cheeka Peak Observatory (CPO) in Washington State. Data from an earlier campaign (March–April 1997 and 1998) were also incorporated. The seasonal cycles of CO and O3 show a spring maximum and a summer minimum, consistent with other remote sites in the marine boundary layer. European and Asian pollution emission sources of CO, parameterized by GEOS‐CHEM, were grouped into one category called “LRT,” representing “long‐range transport.” LRT values produced good correlations with measured CO (monthly averaged r = 0.60, 6‐hour averages) and were found to comprise between 15 and 60% of total CO, with higher values in winter/spring and lower values in the summer/fall. CO and O3 observations were classified on the basis of these LRT values, creating two general categories: “more polluted” (LRT > 75th percentile from monthly distribution) and “less polluted” (LRT < 25th percentile). The difference between these two categories is a measure of the net Asian enhancement above the background and reaches a maximum in the spring of 30‐ppbv CO and in the spring‐fall of 7‐ppbv O3. The Asian O3 enhancement peaked at an average of 4 ppbv from April to October, which is the time of year of greatest urban air quality concerns in North America. Numerous long‐range transport “events” (defined by at least 24 continuous hours of LRT > 75% percentile) were observed throughout the year. Ozone behavior was quite complicated during these events, producing no consistent enhancements. Classification of the measurements with LRT values from GEOS‐CHEM is compared to back trajectories, both isentropic and kinematic. Isentropic trajectories agree reasonably well with GEOS‐CHEM between February and May in capturing the CO enhancements in air masses influenced by recent emissions but were found to be less useful from June to January. HYSPLIT kinematic trajectories were slightly better at capturing the Asian pollution events than isentropic trajectories but still missed an event during the summer completely that was verified by GEOS‐CHEM. Possible reasons for poor trajectory performance in the summer and fall are discussed. Long‐range transport appears not to affect the magnitude of the diurnal variability of O3 measurements at CPO, which reflect daytime production of 2–4 ppbv/d. Rather, ship traffic in the vicinity of CPO, which supplies NOx through combustion, likely plays a dominant role.
Estimating fire emissions and disparities in boreal Siberia (1998–2002)
Authors: Soja Amber J. , Cofer W. Randy , Shugart Herman H. , Sukhinin Anatoly I. , Stackhouse Paul W. , McRae Douglas J. , Conard Susan G.
Published: July 2004

In the biomass, soils, and peatlands of Siberia, boreal Russia holds one of the largest pools of terrestrial carbon. Because Siberia is located where some of the largest temperature increases are expected to occur under current climate change scenarios, stored carbon has the potential to be released with associated changes in fire regimes. Our concentration is on estimating a wide range of current and potential emissions from Siberia on the basis of three modeled scenarios. An area burned product of Siberia is introduced, which spans from 1998 through 2002. Emissions models are spatially explicit; therefore area burned is extracted from associated ecoregions for each year. Carbon consumption estimates are presented for 23 unique ecoregions across Siberia, which range from 3.4 to 75.4 t C ha−1 for three classes of severity. Total direct carbon emissions range from the traditional scenario estimate of 116 Tg C in 1999 (6.9 M ha burned) to the extreme scenario estimate of 520 Tg C in 2002 (11.2 M ha burned), which are equivalent to 5 and 20%, respectively, of total global carbon emissions from forest and grassland burning. Our results suggest that disparities in the amount of carbon stored in unique ecosystems and the severity of fire events can affect total direct carbon emissions by as much as 50%. Additionally, in extreme fire years, total direct carbon emissions can be 37–41% greater than in normal fire years, owing to increased soil organic matter consumption. Mean standard scenario estimates of CO2 (555–1031 Tg), CO (43–80 Tg), CH4 (2.4–4.5 Tg), TNMHC (2.2–4.1 Tg), and carbonaceous aerosols (4.6–8.6 Tg) represent 10, 15, 19, 12 and 26%, respectively, of the global estimates from forest and grassland burning. Accounting for smoldering combustion in soils and peatlands results in increases in CO, CH4, and TNMHC and decreases in CO2 emitted from fire events.
Mars orbital synthetic aperture radar: Obtaining geologic information from radar polarimetry
Authors: Campbell Bruce A. , Maxwell Ted A. , Freeman Anthony
Published: July 2004

Radar penetration of mantling layers, and scattering from buried objects or interfaces, is a topic of current interest in both terrestrial and planetary remote sensing. We examine the behavior of surface and subsurface scattering interfaces and the types of information that may be obtained from observations in different polarizations and wavelengths. These results are applied to the design of a future Mars orbital synthetic aperture radar (SAR), for which we draw the following conclusions. (1) Mapping of buried geologic features is best accomplished using VV polarization, at an optimal wavelength determined by the competing effects of antenna gain, attenuation in the dust, and the reduction in effective surface roughness with wavelength. P band frequencies (∼1 GHz or less) offer the best opportunity for detection of moderately rough, buried features. (2) The relative roles of surface and subsurface scattering may be determined using measurements in HH and VV polarization, with a channel gain calibration better than 0.5 dB. (3) The thickness of a mantling layer (or ice mass) cannot be directly inferred from multiwavelength observations. Layer thickness may be inferred from the interferometric correlation of backscatter measurements collected on suitably spaced orbital passes, though the required phase measurement accuracy is challenging. While additional information may be gained by collecting scattering data in more polarizations or wavelengths, we suggest that the primary science goals of a Mars‐orbiting radar could be accomplished by a single‐wavelength system capable of collecting VV and HH polarizations with the calibration and orbit control needed to permit interferometric analysis.
Cooperation and the Capacity for Control: Regulatory Styles and the Evolving Influence of Environmental Regulations in the UK
Authors: Gouldson Andy
Published: July 2004

This paper seeks to contribute to the broader debate on how to promote ‘better regulation’ by examining the origins and influence of different regulatory styles. More particularly it examines the extent to which economic theories of cooperation can help to explain the presence of the cooperative regulatory style that has long been associated with the implementation of environmental regulations in the United Kingdom. After reporting the results of empirical research that focused on these issues, it concludes that cooperative regulatory styles are likely to depend upon: (a) the presence of inter-dependencies between regulators and firms; and either (b) the presence of trust amongst stakeholders; or (c) the effective exclusion of those stakeholders from influence in the regulatory decisionmaking process. Highlighting the importance of recent changes in each of these three areas in the United Kingdom, it explains the factors that have led to a shift away from a purely cooperative approach towards what has been termed a more ‘responsive’ or ‘risk-based’ approach. Recognising that such changes have been driven by a desire to enhance the efficacy and the efficiency of environmental regulation, and by concerns about the lack of transparency and accountability in the regulatory process, it concludes that such evolutions represent an important contribution to the debate on regulation and its reform.
Shifts in Environmental Governance in Canada: How are Citizen Environment Groups to Respond?
Authors: Savan Beth , Gore Christopher , Morgan Alexis J
Published: July 2004

During a period when the relationship between government agencies and citizen environmental monitoring activities is shifting, this paper examines the nature of the relationship between government and citizen stewardship, by describing some citizen monitoring initiatives in Ontario, Canada. The authors begin by characterizing the changing nature of environmental governance by focusing specifically on the complexity surrounding the relationship between government administrative reform, demands for improved and increased environmental monitoring, and the role and function of citizens in monitoring activities. Then, building on the experience of one citizen-based environmental organization, Citizens' Environment Watch, as well as on two other local examples, they document possible new forms of collaboration that retain government responsibility while building community authority, knowledge, and power to improve local environmental quality. Suggested remedies include a recognition and public articulation of what government should do and what it does not do. In the case of the latter, government should commit to provide support for citizen monitoring efforts, and to heed the work of volunteer monitors. Finally, government needs to follow up on concerns about degraded environmental quality raised by local citizens through strong investigative and enforcement responses.
Townscape Heritage Initiatives Evaluation: Methodology for Assessing the Effectiveness of Heritage Lottery Fund Projects in the United Kingdom
Authors: Shipley Robert , Reeve Alan , Walker Stephen , Grover Philip , Goodey Brian
Published: July 2004

As a result of various social and economic factors, many historic townscapes in the United Kingdom and elsewhere have declined over the last half century. There have been many attempts throughout the world to revitalise such urban heritage areas, but the actual effectiveness of few of these schemes has been systematically evaluated. Good public policy choices would greatly benefit from such evaluation. The UK's Heritage Lottery Fund (HLF) decided in 1999 that their Townscape Heritage Initiatives would be an exception. A research team from Oxford Brookes University was engaged to undertake a ten-year study of the £52 million being spent in about sixty British towns and cities. A sample of about one third of projects receiving HLF support are being scrutinised. The evaluation methodology is outlined, along with explanations of some challenges faced in such a large programme. The four mechanisms for gathering research data are explained, the origin and rationale for the sixteen indicators being employed are described, and the approach to overall evaluation outlined. Finally there is an overview of the baseline stage of the work, highlighting key issues from a research perspective, and briefly reflecting on findings to date.
A model for the function of sperm DNA degradation
Authors: Ward Monika A. , Ward W. Steven
Published: July 2004

In this review, we present our recent evidence suggesting, but not yet proving, that mammalian spermatozoa contain a mechanism by which they can digest their own DNA when exposed to a stressful environment. We discuss our recent data that demonstrate that when mammalian spermatozoa are treated in a variety of ways, the paternal chromosomes in the zygote, or the sperm DNA itself, are degraded into large, chromosome-sized fragments. These published data support the existence of nuclease activity in spermatozoa. We suggest that this nuclease activity is part of a mechanism the spermatozoon uses when it encounters a stressful environment to prevent fertilisation and to avoid the transmission of potentially damaged DNA to the embryo. We propose a model based on sperm chromatin structure by which this nuclease can digest the highly condensed sperm chromatin.
CCAAT displacement protein/
cut
homolog recruits G9a histone lysine methyltransferase to repress transcription
Authors: Nishio Hitomi , Walsh Martin J.
Published: July 2004

CCAAT displacement protein/
cut
homolog (CDP/
cut
) is a highly conserved homeodomain protein that contains three
cut
repeat sequences. CDP/
cut
is a transcriptional factor for many diverse cellular and viral genes that are involved in most cellular processes, including differentiation, development, and proliferation. Here, we report that CDP/
cut
interacts with a histone lysine methyltransferase (HKMT), G9a,
in vivo
and
in vitro
. The deletion of the
cut
repeats within CDP/
cut
abrogates the interaction with G9a. The transcriptional repressor function of CDP/
cut
is mediated through HKMT activity of G9a associated with CDP/
cut
. We show that the recruitment of G9a to the human p21

waf1/cdi1

promoter is contingent on the interaction with CDP/
cut
, and CDP/
cut
is directly associated with an increase in the methylation
in vivo
of Lys-9 in histone H3 within the CDP/
cut
-regulatory region of the p21

waf1/cdi1

promoter. The endogenous level of p21

waf1/cdi1

expression is repressed through CDP/
cut
and mediated by HKMT activity of G9a. Furthermore, we report the identification of G9a as a component of CDP/
cut
complex. G9a colocalizes with CDP/
cut
in the nucleus. These results indicate that G9a functions as a transcriptional corepressor in association with a CDP/
cut
complex. These studies now reveal the interaction of G9a with a sequence-specific transcription factor that regulates gene repression through CDP/
cut
.
Anchor residues in protein–protein interactions
Authors: Rajamani Deepa , Thiel Spencer , Vajda Sandor , Camacho Carlos J.
Published: July 2004

We show that the mechanism for molecular recognition requires one of the interacting proteins, usually the smaller of the two, to anchor a specific side chain in a structurally constrained binding groove of the other protein, providing a steric constraint that helps to stabilize a native-like bound intermediate. We identify the anchor residues in 39 protein–protein complexes and verify that, even in the absence of their interacting partners, the anchor side chains are found in conformations similar to those observed in the bound complex. These ready-made recognition motifs correspond to surface side chains that bury the largest solvent-accessible surface area after forming the complex (≥100 Å
2
). The existence of such anchors implies that binding pathways can avoid kinetically costly structural rearrangements at the core of the binding interface, allowing for a relatively smooth recognition process. Once anchors are docked, an induced fit process further contributes to forming the final high-affinity complex. This later stage involves flexible (solvent-exposed) side chains that latch to the encounter complex in the periphery of the binding pocket. Our results suggest that the evolutionary conservation of anchor side chains applies to the actual structure that these residues assume before the encounter complex and not just to their loci. Implications for protein docking are also discussed.
Molecular structure of double-minute chromosomes bearing amplified copies of the epidermal growth factor receptor gene in gliomas
Authors: Vogt Nicolas , Lefèvre Sandrine-Hélène , Apiou Françoise , Dutrillaux Anne-Marie , Cör Andrej , Leuraud Pascal , Poupon Marie-France , Dutrillaux Bernard , Debatisse Michelle , Malfoy Bernard
Published: July 2004

Amplification of the epidermal growth factor receptor gene on double minutes is recurrently observed in cells of advanced gliomas, but the structure of these extrachromosomal circular DNA molecules and the mechanisms responsible for their formation are still poorly understood. By using quantitative PCR and chromosome walking, we investigated the genetic content and the organization of the repeats in the double minutes of seven gliomas. It was established that all of the amplicons of a given tumor derive from a single founding extrachromosomal DNA molecule. In each of these gliomas, the founding molecule was generated by a simple event that circularizes a chromosome fragment overlapping the epidermal growth factor receptor gene. In all cases, the fusion of the two ends of this initial amplicon resulted from microhomology-based nonhomologous end-joining. Furthermore, the corresponding chromosomal loci were not rearranged, which strongly suggests that a postreplicative event was responsible for the formation of each of these initial amplicons.
A specific gene expression program triggered by Gram-positive bacteria in the cytosol
Authors: McCaffrey Ramona L. , Fawcett Paul , O'Riordan Mary , Lee Kyung-Dall , Havell Edward A. , Brown Patrick O. , Portnoy Daniel A.
Published: July 2004

Innate and adaptive immunity depends critically on host recognition of pathogen-associated molecules. Toll-like receptors (TLRs) are key mediators of pathogen surveillance at the cell or phagocytic vacuole surface. However, mechanisms underlying recognition of pathogens in other cellular compartments remain unclear, and responses elicited by cytosolic challenge are poorly characterized. We therefore used mouse cDNA microarrays to investigate gene expression triggered by infection of bone marrow-derived macrophages with cytosol- and vacuole-localized
Listeria monocytogenes
(
Lm
), a model cytosolic pathogen. The resulting gene expression program included two basic categories of induced genes: an “early/persistent” cluster consistent with NF-κB-dependent responses downstream of TLRs, and a subsequent “late response” cluster largely composed of IFN-responsive genes (IRGs). The early/persistent cluster was observed upon infection with WT, heat-killed, or mutant
Lm
lacking listeriolysin O, the pore-forming hemolysin that promotes escape from phagocytic vacuoles. However, the IRG cluster depended on entry of WT
Lm
into the cytosol. Infection with listeriolysin O-expressing, cytosolic
Bacillus subtilis
(
Bs
) strikingly recapitulated the expression profile associated with WT
Lm
, including IRG induction. IRG up-regulation was associated with MyD88-independent induction of IFN-β transcription and activity. Whereas
Staphylococcus aureus
(
Sa
) lipoteichoic acid treatment confirmed that many late-response genes could also be stimulated through TLRs, our study identified a cytosol-specific transcriptional program independent of TLR signaling through MyD88. Further characterization of cytosolic surveillance pathway(s) and their points of convergence with TLR- and IFN-dependent pathways will enhance our understanding of the means by which mammals detect and respond to pathogens.
Autoantigen Golgin-97, an Effector of Arl1 GTPase, Participates in Traffic from the Endosome to theTrans-Golgi Network
Authors: Lu Lei , Tai Guihua , Hong Wanjin
Published: July 2004

The precise cellular function of Arl1 and its effectors, the GRIP domain Golgins, is not resolved, despite our recent understanding that Arl1 regulates the membrane recruitment of these Golgins. In this report, we describe our functional study of Golgin-97. Using a Shiga toxin B fragment (STxB)-based in vitro transport assay, we demonstrated that Golgin-97 plays a role in transport from the endosome to the trans-Golgi network (TGN). The recombinant GRIP domain of Golgin-97 as well as antibodies against Golgin-97 inhibited the transport of STxB in vitro. Membrane-associated Golgin-97, but not its cytosolic pool, was required in the in vitro transport assay. The kinetic characterization of inhibition by anti-Golgin-97 antibody in comparison with anti-Syntaxin 16 antibody established that Golgin-97 acts before Syntaxin 16 in endosome-to-TGN transport. Knock down of Golgin-97 or Arl1 by their respective small interference RNAs (siRNAs) also significantly inhibited the transport of STxB to the Golgi in vivo. In siRNA-treated cells with reduced levels of Arl1, internalized STxB was instead distributed peripherally. Microinjection of Golgin-97 antibody led to the fragmentation of Golgi apparatus and the arrested transport to the Golgi of internalized Cholera toxin B fragment. We suggest that Golgin-97 may function as a tethering molecule in endosome-to-TGN retrograde traffic.
Kinetochore Localization of Spindle Checkpoint Proteins: Who Controls Whom?
Authors: Vigneron Suzanne , Prieto Susana , Bernis Cyril , Labbé Jean-Claude , Castro Anna , Lorca Thierry
Published: July 2004

The spindle checkpoint prevents anaphase onset until all the chromosomes have successfully attached to the spindle microtubules. The mechanisms by which unattached kinetochores trigger and transmit a primary signal are poorly understood, although it seems to be dependent at least in part, on the kinetochore localization of the different checkpoint components. By using protein immunodepletion and mRNA translation in Xenopus egg extracts, we have studied the hierarchic sequence and the interdependent network that governs protein recruitment at the kinetochore in the spindle checkpoint pathway. Our results show that the first regulatory step of this cascade is defined by Aurora B/INCENP complex. Aurora B/INCENP controls the activation of a second regulatory level by inducing at the kinetochore the localization of Mps1, Bub1, Bub3, and CENP-E. This localization, in turn, promotes the recruitment to the kinetochore of Mad1/Mad2, Cdc20, and the anaphase promoting complex (APC). Unlike Aurora B/INCENP, Mps1, Bub1, and CENP-E, the downstream checkpoint protein Mad1 does not regulate the kinetochore localization of either Cdc20 or APC. Similarly, Cdc20 and APC do not require each other to be localized at these chromosome structures. Thus, at the last step of the spindle checkpoint cascade, Mad1/Mad2, Cdc20, and APC are recruited at the kinetochores independently from each other.
Cell-specific Nucleolar Localization of TBP-related Factor 2
Authors: Kieffer-Kwon Philippe , Martianov Igor , Davidson Irwin
Published: July 2004

TATA-binding protein (TBP)-related factor 2 (TRF2) is one of four closely related RNA polymerase II transcription factors. We compared the intracellular localizations of TBP and TRF2 during the cell cycle and mitosis in HeLa cells. We show that during interphase, endogenous or exogenously expressed TRF2 is located almost exclusively in the nucleolus in HeLa or Cos cells. TRF2 localization is not affected by stress or mitotic stimuli, but TRF2 is rapidly released from the nucleolus upon inhibition of pol I transcription or treatment by RNase. These results suggest that localization of HeLa TRF2 requires a nucleolar-associated RNA species. In contrast, in 3T3 fibroblast cells, exogenously expressed TRF2 localizes to the nucleoplasm. Constitutive expression of ectopic TRF2 in 3T3 cells leads to a prolonged S phase of the cell cycle and reduced proliferation. Together with previous data, our results highlight the cell-specific localization and functions of TRF2. Furthermore, we show that during cell division, HeLa TRF2 and TBP are localized in the mitotic cytoplasm and TRF2 relocalizes into the nascent nucleoli immediately after mitosis, whereas TBP reassociates with the chromatin. Although partially contradictory results have been reported, our data are consistent with a model where only small proportion of the cellular TBP remains associated with specific promoter loci during mitosis.
Transcription Profiling of Cyclic AMP Signaling inCandida albicans
Authors: Harcus Doreen , Nantel André , Marcil Anne , Rigby Tracey , Whiteway Malcolm
Published: July 2004

We used transcription profiling in Candida albicans to investigate cellular regulation involving cAMP. We found that many genes require the adenylyl cyclase Cdc35p for proper expression. These include genes encoding ribosomal subunit proteins and RNA polymerase subunit proteins, suggesting that growth could be controlled in part by cAMP-mediated modulation of gene expression. Other genes influenced by loss of adenylyl cyclase are involved in metabolism, the cell wall, and stress response and include a group of genes of unknown function that are unique to C. albicans. The profiles generated by loss of the adenylyl cyclase regulator Ras1p and a downstream effector Efg1p were also examined. The loss of Ras1p function disturbs the expression of a subset of the genes regulated by adenylyl cyclase, suggesting both that the primary role of Ras1p in transcriptional regulation involves its influence on the function of Cdc35p and that there are Ras1p independent roles for Cdc35p. The transcription factor Efg1p is also needed for the expression of many genes; however, these genes are distinct from those modulated by Cdc35p with the exception of a class of hyphal-specific genes. Therefore transcription profiling establishes that cAMP plays a key role in the overall regulation of gene expression in C. albicans, and enhances our detailed understanding of the circuitry controlling this regulation.
Glucose Mediates Transcriptional Repression of the Human Angiotensin Type-1 Receptor Gene: Role for a NovelCis-acting Element
Authors: Thomas Beena E. , Thekkumkara Thomas J.
Published: July 2004

Human angiotensin type 1 receptor (hAT1R) gene is regulated by hormones, second messengers, and both pathophysiological and developmental states. The focus of the present study was to determine the role of glucose in the trans-repression of hAT1R gene transcription and to identify the functional cis-acting response element(s). Serial deletions of the hAT1R promoter region indicated that an area between –1717 and –1543 base pairs upstream of the 5′ end of the cDNA sequence has a glucose responsive regulatory element (GluRE) to down-regulate the gene expression. Further analysis revealed a putative 29-bp (5′-AACTGATTTTTGTATATTGATCTTGTATT-3′) repressor element located between –1582 and -1610 bp was necessary for transcriptional repression. Removal of this region from promoter construct abolished repression of the hAT1R gene transcription in human proximal tubule epithelial cells (hPTECs). Using mobility shift assays, we demonstrated DNA binding activity to the labeled repressor element in hPTEC nuclear extracts. Additional studies demonstrated increased DNA binding activity to the labeled repressor element in nuclear extracts treated with high glucose (25 mM). Southwestern analysis identified two GluRE binding proteins of 34 and 36 kDa in glucose-treated extracts. Glucose-induced activity of the repressor trans-acting factor(s) reached a maximum at 4 h, which correlated with decreased transcriptional activity of the hAT1R gene, suggesting that glucose can down-regulate the transcription of the hAT1R gene through the repressor element. Furthermore, insertion of the glucose response element into heterologous SV40 promoter (SV40) chloramphenicol acetyl transferase (CAT) vector showed orientation/distance-independent repression of SV40 promoter-mediated CAT activity in hPTECs. Our results show that the glucose response factor(s) acts as trans-acting factor(s) binding to the cis-acting repressor element in the hAT1R promoter, which may participate in the control of basal transcription as well as glucose-mediated transcriptional inhibition of the hAT1R gene.
TetraThymosinβ Is Required for Actin Dynamics inCaenorhabditis elegansand Acts via Functionally Different Actin-binding Repeats
Authors: Van Troys Marleen , Ono Kanako , Dewitte Daisy , Jonckheere Veronique , De Ruyck Natalie , Vandekerckhove Joël , Ono Shoichiro , Ampe Christophe
Published: July 2004

Generating specific actin structures via controlled actin polymerization is a prerequisite for eukaryote development and reproduction. We here report on an essential Caenorhabditis elegans protein tetraThymosinβ expressed in developing neurons and crucial during oocyte maturation in adults. TetraThymosinβ has four repeats, each related to the actin monomer-sequestering protein thymosinβ 4 and assists in actin filament elongation. For homologues with similar multirepeat structures, a profilin-like mechanism of ushering actin onto filament barbed ends, based on the formation of a 1:1 complex, is proposed to underlie this activity. We, however, demonstrate that tetraThymosinβ binds multiple actin monomers via different repeats and in addition also interacts with filamentous actin. All repeats need to be functional for attaining full activity in various in vitro assays. The activities on actin are thus a direct consequence of the repeated structure. In containing both G- and F-actin interaction sites, tetraThymosinβ may be reminiscent of nonhomologous multimodular actin regulatory proteins implicated in actin filament dynamics. A mutation that suppresses expression of tetraThymosinβ is homozygous lethal. Mutant organisms develop into adults but display a dumpy phenotype and fail to reproduce as their oocytes lack essential actin structures. This strongly suggests that the activity of tetraThymosinβ is of crucial importance at specific developmental stages requiring actin polymerization.
A Dynein Light Intermediate Chain, D1bLIC, Is Required for Retrograde Intraflagellar Transport
Authors: Hou Yuqing , Pazour Gregory J. , Witman George B.
Published: July 2004

Intraflagellar transport (IFT), the bidirectional movement of particles along flagella, is essential for flagellar assembly. The motor for retrograde IFT in Chlamydomonas is cytoplasmic dynein 1b, which contains the dynein heavy chain DHC1b and the light intermediate chain (LIC) D1bLIC. To investigate a possible role for the LIC in IFT, we identified a d1blic mutant. DHC1b is reduced in the mutant, indicating that D1bLIC is important for stabilizing dynein 1b. The mutant has variable length flagella that accumulate IFT-particle proteins, indicative of a defect in retrograde IFT. Interestingly, the remaining DHC1b is normally distributed in the mutant flagella, strongly suggesting that the defect is in binding of cargo to the retrograde motor rather than in motor activity per se. Cell growth and Golgi apparatus localization and morphology are normal in the mutant, indicating that D1bLIC is involved mainly in retrograde IFT. Like mammalian LICs, D1bLIC has a phosphate-binding domain (P-loop) at its N-terminus. To investigate the function of this conserved domain, d1blic mutant cells were transformed with constructs designed to express D1bLIC proteins with mutated P-loops. The constructs rescued the mutant cells to a wild-type phenotype, indicating that the function of D1bLIC in IFT is independent of its P-loop.
Study on Application of Static Magnetic Field for Adjuvant Arthritis Rats
Authors: Taniguchi Norimasa , Kanai Shigeyuki , Kawamoto Masazumi , Endo Hiroshi , Higashino Hideaki
Published: July 2004

In order to examine the effectiveness of the application of static magnetic field (SMF) on pain relief, we performed a study on rats with adjuvant arthritis (AA). Sixty female Sprague–Dawley (SD) rats (age: 6 weeks, body weight: approximately 160 g) were divided into three groups [SMF‐treated AA rats (Group I), non‐SMF‐treated AA rats (Group II) and control rats (Group III)]. The SD rats were injected in the left hind leg with 0.6 mg/0.05 ml Mycobacterium butyrium to induce AA. The rats were bred for 6 months as chronic pain model. Thereafter, the AA rats were or were not exposed to SMF for 12 weeks. We assessed the changes in the tail surface temperature, locomotor activity, serum inflammatory marker and bone mineral density (BMD) using thermography, a metabolism measuring system and the dual‐energy X‐ray absorptiometry (DEXA) method, respectively. The tail surface temperature, locomotor activity and femoral BMD of the SMF‐exposed AA rats were significantly higher than those of the non‐SMF‐exposed AA rats, and the serum inflammatory marker was significantly lower. These findings suggest that the pain relief effects are primarily due to the increased blood circulation caused by the rise in the tail surface temperature. Moreover, the pain relief effects increased with activity and BMD of the AA rats.
An Alternative Approach to Atopic Dermatitis: Part II—Summary of Cases and Discussion
Authors: Kobayashi Hiromi , Takahashi Kuniaki , Mizuno Nobuyuki , Kutsuna Haruo , Ishii Masamitsu
Published: July 2004

In the first part of this Review, we presented case‐series where Kampo treatment was introduced for those atopic dermatitis (AD) patients who had failed with conventional therapy, in an attempt to prove that there exists a definite subgroup of AD patients for whom Kampo treatment is effective. In this second part, we will first provide the summary of the results for 140 AD patients we treated in 2000. The results suggest that Kampo treatment is effective for more than half of AD patients who fail with conventional therapy. In the Discussion, we will examine the evidential basis for conventional AD therapy and discuss how Kampo treatment should be integrated into the guidelines for AD therapy. We contend that Kampo treatment should be tried before systematic immunosuppressive agents are considered. As each Kampo treatment is highly individualized, it should be regarded more as ‘art’ than technology, and special care should be taken to assess its efficacy in clinical trial.
Macromolecular Cryocrystallography: Cooling, Mounting, Storage and Transportation of Crystals
Authors: Parkin Sean , Hope Håkon
Published: July 2004

Simple methods are presented for handling, mounting, storage and transportation of crystals at cryogenic temperatures. They are easy to learn and have a number of technical and operational advantages over currently popular methods. In particular, the temperature of the crystal throughout all manipulations is known; it is shown never to rise above that of the warmest component of the cryogenic system, typically the cold gas stream of the low-temperature apparatus. Crystals can be mounted and inspected in the home laboratory prior to transportation to a synchrotron, giving dramatic savings in experimental time and effort. Provided appropriate care is taken, crystals remain frost free throughout any number of mount–dismount cycles.
Neutron Transmission of Single-Crystal Sapphire
Authors: Mildner D. F. R. , Lamaze G. P.
Published: July 2004

Thermal and cold neutron transmission time-of-flight measurements have been taken on blocks of single-crystal sapphire. The transmission characteristics of single-crystal sapphire are not altered by irradiation for a number of years within a beam port at a reactor. Cooling the filter is only useful for the production of beams with the longest wavelengths. Even for poorer grade sapphire there is no degradation of the neutron transmission characteristics.
Neutron Transmission of a Single-Crystal MgO Filter
Authors: Thiyagarajan P. , Crawford R. K. , Mildner D. F. R.
Published: July 2004

The neutron transmission probability through a single-crystal MgO filter has been measured at both liquid-nitrogen (77 K) and room (300 K) temperatures, as a function of wavelength, using a pulsed neutron source. The data show that a cooled MgO filter is superior to room-temperature sapphire for both thermal and cold neutrons, principally because the absorption probability is reduced by a factor of three at long wavelengths.
Organization Modes and Electron Radiation Damage of Cardiolipin Crystals
Authors: Valdrè Giovanni , Muscatello Umberto
Published: July 2004

Cardiolipin (tetraacyldiphosphatidylglycerol) microcrystals have been studied by transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). Different preparation methods lead to different aggregation modes. It is also found that cardiolipin crystals are very susceptible to electron radiation damage, the dosedlrequired for the disappearance of the diffraction intensity being about 10^{-3} C cm^{-2} (corresponding to a transferred energy density of about 10–20 eV nm^{-3}), very close to that of aliphatic amino acids and paraffin. This transferred energy density is compatible with the energy required for the rupture of the C–C and C–H bonds. The damage does not appear to nucleate randomly, but in specific parts of the crystals where the structure is distorted as a result of bending, structural defects, or a less organized packing. The finest organized structures revealed by low-dose TEM are rather coarse, of the order of a nanometre, whereas SAED shows the presence of periodicities down to 0.2 nm.
Structure Investigations of Molecular Crystals Containing the Ring System Cyclo-tris(2,6-pyridylformamidine) by Means of X-ray Powder Diffraction and Force-Field-Constrained Rietveld Refinement
Authors: Friedel P. , Tobisch J. , Jehnichen D. , Bergmann J. , Taut T. , Rillich M. , Kunert C. , Böhme F.
Published: July 2004

A new heterocyclic compound, cyclo-tris(2,6-pyridylformamidine), was synthesized as a highly crystalline powder-like substance from which very small whiskers were produced by a sublimation technique. By rotating-crystal and powder diffraction measurements, a set of structural data were obtained which were fitted mathematically to a structural model. The fitting procedure included geometry optimization byab initiocalculations, crystal structure and X-ray diffraction pattern simulation as well as structure refinement based on the newly developed Rietveld algorithmBGMN®under force-field constraints. A single-crystal structure refinement could not be carried out because of the small size of the whiskers. In order to obtain the atomic coordinates a new procedure incorporating a powder diffraction pattern refinement was used. Cyclo-tris(2,6-pyridylformamidine) crystallizes in a monoclinic unit cell witha = 28.18 (1),b = 14.67 (1),c = 4.428 (1) Å, β = 90.10 (2)°. The symmetry was determined asP21/a. The expected threefold symmetry of the cyclic compound was disturbed in the crystallized state, in agreement with solid-state NMR investigations. The best approximation was obtained when water molecules were additionally packed into the unit cell.