bluuebunny/crossref_metadata_2025 huggingface dataset:
A pilot survey of socio-economic differences in child-feeding behaviours among parents of primary-school children
Authors: Clark Heather R , Goyder Elizabeth , Bissell Paul , Blank Lindsay , Walters Stephen J , Peters Jean
Published: December 2007

Objective

Parents’ child-feeding behaviours have been implicated in children’s food choices and weight, but little is known about the social class distribution of parent’s child-feeding behaviours in the UK. The present study compares parents’ self-reported child-feeding behaviours in two socio-economically contrasting areas.

Design

A cross-sectional survey using the Parental Feeding Style Questionnaire. Mean scores were calculated for five child-feeding behaviours: control over eating, emotional feeding, encouragement/prompting, instrumental feeding and restriction. Parents’ self-reported child-feeding behaviours were compared with their sociodemographic characteristics.

Setting

Three primary schools in two contrasting electoral wards of Sheffield, UK.

Subjects

Two hundred and ten parents of children aged 4 to 11 years, recruited from a convenience sample.

Results

Parents in the least deprived ward reported using all five types of child-feeding behaviour more frequently than parents in the most deprived ward. After adjusting for parent sex, parent age, single parent status, employment status and level of education, emotional feeding was the only behaviour showing any evidence of a difference between wards. The most frequently used behaviours were control, encouragement and restriction – behaviours that might be used to directly influence children’s food intake and weight.

Conclusions

Child-feeding behaviours differ between areas within a single city and within a largely white population, and this distribution is related to socio-economic and educational factors. Experimental and longitudinal studies are needed to further investigate the potential role of child-feeding behaviours in childhood overweight and obesity.
Plädoyer für eine sozialere und dadurch interdisziplinärere und anwendbarere Sozialpsychologie
Authors: Scholl Wolfgang
Published: December 2007

Zusammenfassung: Die psychologische Sozialpsychologie hat sich zu einer relativ individualistischen Disziplin entwickelt, in der das “Soziale” zunehmend verkürzt wurde. Es wird gezeigt, dass Themen, die die wechselseitige Interaktion und Kommunikation zwischen Individuen betreffen und in die konkrete Sozialstruktur und Kultur einbetten, zu wenig in Forschung und Lehre angegangen werden. Darunter leiden auch die wechselseitige Befruchtung mit den Nachbarwissenschaften und die Nützlichkeit der psychologischen Sozialpsychologie für die Praxis. Eine stärkere Ausarbeitung und Verknüpfung der interaktiven Paradigmen der Austauschtheorien und des symbolischen Interaktionismus untereinander und mit dem Social-Cognition-Paradigma könnte die individualistische Verkürzung korrigieren und die psychologische Sozialpsychologie sozialer, interdisziplinärer und anwendbarer machen.
Gravitational trapping of carbon dioxide in deep sea sediments: Permeability, buoyancy, and geomechanical analysis
Authors: Levine J. S. , Matter J. M. , Goldberg D. , Cook A. , Lackner K. S.
Published: December 2007

Liquid carbon dioxide injected in deep‐sea sediments at km depths and near freezing temperatures is denser than surrounding pore water and will be trapped by gravitational forces. Storage capacity for CO2 in such formations below the ocean floor is shown to vary with seafloor depth, geothermal gradient, porosity, and pore water salinity. The formation permeability, or the successful engineering of such permeability through hydraulic fracturing, will determine the capacity for gravitational trapping in deep‐sea geological formations. We conclude that most ocean sediments at appropriate depth will lack the required permeability and that conventional hydraulic fracturing would only be possible in carefully selected sites.
Surface CO2 leakage during two shallow subsurface CO2 releases
Authors: Lewicki J. L. , Oldenburg C. M. , Dobeck L. , Spangler L.
Published: December 2007

A new field facility was used to study CO2 migration processes and test techniques to detect and quantify potential CO2 leakage from geologic storage sites. For 10 days starting 9 July 2007, and for seven days starting 3 August 2007, 0.1 and 0.3 t CO2 d−1, respectively, were released from a ∼100‐m long, sub‐water table (∼2.5‐m depth) horizontal well. The spatio‐temporal evolution of leakage was mapped through repeated grid measurements of soil CO2 flux (FCO2). The surface leakage onset, approach to steady state, and post‐release decline matched model predictions closely. Modeling suggested that minimal CO2 was taken up by groundwater through dissolution, and CO2 spread out on top of the water table. FCO2 spatial patterns were related to well design and soil physical properties. Estimates of total CO2 discharge along with soil respiration and leakage discharge highlight the influence of background CO2 flux variations on detection of CO2 leakage signals.
Basin‐wide seasonal evolution of the Indian Ocean's phytoplankton blooms
Authors: Lévy M. , Shankar D. , André J.‐M. , Shenoi S. S. C. , Durand F. , de Boyer Montégut C.
Published: December 2007

A climatology of Sea‐viewing Wide Field‐of‐View Sensor (SeaWiFS) chlorophyll data over the Indian Ocean is used to examine the bloom variability patterns, identifying spatio‐temporal contrasts in bloom appearance and intensity and relating them to the variability of the physical environment. The near‐surface ocean dynamics is assessed using an ocean general circulation model (OGCM). It is found that over a large part of the basin, the seasonal cycle of phytoplankton is characterized by two consecutive blooms, one during the summer monsoon, and the other during the winter monsoon. Each bloom is described by means of two parameters, the timing of the bloom onset and the cumulated increase in chlorophyll during the bloom. This yields a regional image of the influence of the two monsoons on phytoplankton, with distinct regions emerging in summer and in winter. By comparing the bloom patterns with dynamical features derived from the OGCM (horizontal and vertical velocities and mixed‐layer depth), it is shown that the regional structure of the blooms is intimately linked with the horizontal and vertical circulations forced by the monsoons. Moreover, this comparison permits the assessment of some of the physical mechanisms that drive the bloom patterns, and points out the regions where these mechanisms need to be further investigated. A new outcome of this study is that in many distinct areas, time shifts of 1–2 months are witnessed in the timing of the bloom onsets in adjoining regions. These time shifts are rationalized in terms of horizontal advection and Rossby wave propagation.
An incremental theory of double edge diffraction
Authors: Toccafondi A. , Tiberio R.
Published: December 2007

A novel general procedure for defining incremental field contributions for double diffraction at a pair of perfectly conducting (PEC) wedges in an arbitrary configuration is presented. The new formulation provides an accurate first‐order asymptotic description of the interaction between two edges, which is valid both for skewed separate wedges and for edges joined by a common PEC face. It also includes a double incremental slope diffraction augmentation, which provides the correct dominant high‐frequency incremental contribution at grazing aspect of incidence and observation. This new formulation is obtained by applying to both edges, the wedge‐shaped incremental dyadic diffraction coefficients for single edge diffraction. The total doubly diffracted field is obtained from a double spatial integration along each of the two edges on which consecutive diffractions occur. It is found that this distributed field representation precisely recovers the doubly diffracted field predicted by the uniform theory of diffraction (UTD) and that may be applied to complement ray field methods close to and at caustics. It can be applied as well in all those situations in which a stationary phase condition is not yet well established. Numerical examples are presented and compared with those calculated from both Method of Moment solution and second‐order UTD ray techniques. Excellent agreement was found in all cases examined.
A glass always half full: Reconsideration of the Wales apparatus to apply constant head boundary conditions
Authors: Ferre Ty P. A. , Selker John S.
Published: December 2007

A new apparatus is presented that is capable of applying a constant fluid pressure at inflow and outflow boundaries. The apparatus can be refilled during operation and does not rely on an overflow mechanism. The device is constructed of two vessels, one that contains the delivered fluid and the other that contains a less dense fluid. By matching the fluid densities and the areas of the vessels the absolute elevation of the delivered fluid is maintained as the fluid is added to or removed from the system. The history of the development of the device, the underlying physical principles, and two demonstrations of the operation of a prototype device are shown.
The emergence of land change science for global environmental change and sustainability
Authors: Turner B. L. , Lambin Eric F. , Reenberg Anette
Published: December 2007

Land change science has emerged as a fundamental component of global environmental change and sustainability research. This interdisciplinary field seeks to understand the dynamics of land cover and land use as a coupled human–environment system to address theory, concepts, models, and applications relevant to environmental and societal problems, including the intersection of the two. The major components and advances in land change are addressed: observation and monitoring; understanding the coupled system—causes, impacts, and consequences; modeling; and synthesis issues. The six articles of the special feature are introduced and situated within these components of study.
ArabidopsisCBF1 and CBF3 have a different function than CBF2 in cold acclimation and define different gene classes in the CBF regulon
Authors: Novillo Fernando , Medina Joaquín , Salinas Julio
Published: December 2007

The C-repeat-binding factor (CBF)/dehydration-responsive element-binding factor (DREB1) proteins constitute a small family ofArabidopsistranscriptional activators (CBF1/DREB1B, CBF2/DREB1C, and CBF3/DREB1A) that play a prominent role in cold acclimation. A fundamental question about these factors that remains to be answered is whether they are functionally equivalent. Recently, we reported that CBF2 negatively regulatesCBF1andCBF3expression, and thatCBFsare subjected to different temporal regulation during cold acclimation, which suggested this might not be the case. In this study, we have analyzed the expression ofCBFgenes in different tissues ofArabidopsis, during development and in response to low temperature, and characterized RNA interference (RNAi) and antisense lines that fail to accumulateCBF1or/andCBF3mRNAs under cold conditions. We found thatCBF1andCBF3are regulated in a different way thanCBF2. Moreover, in contrast to CBF2, CBF1 and CBF3 are not involved in regulating otherCBFgenes and positively regulate cold acclimation by activating the same subset of CBF-target genes. All these results demonstrate that CBF1 and CBF3 have different functions than CBF2. We also found that the CBF regulon is composed of at least two different kind of genes, one of them requiring the simultaneous expression of bothCBF1andCBF3to be properly induced. This indicates that CBF1 and CBF3 have a concerted additive effect to induce the whole CBF regulon and the complete development of cold acclimation.
Trophic ecology of invasive Argentine ants in their native and introduced ranges
Authors: Tillberg Chadwick V. , Holway David A. , LeBrun Edward G. , Suarez Andrew V.
Published: December 2007

Although the ecological effects of invasions often become obvious soon after introduced species become established, more gradual effects may take years to manifest and can thus require long-term data for quantification. We analyzed an 8-year record of stable isotope data on Argentine ants (
Linepithema humile
) from southern California to infer how the trophic position of this widespread invasive species changes over time as native ant species are displaced. We couple this longitudinal analysis with a biregional comparison of stable isotope data (δ
15
N) on ants from Argentina (native range) and California (introduced range) to quantify (
i
) how the trophic position of
L. humile
differs between native and introduced populations, and (
ii
) how relative trophic position as estimated by δ
15
N values of Argentine ants compare with those of other ants at the same site. Both long-term and biregional comparisons indicate that the Argentine ant's relative trophic position is reduced at sites with a longer history of occupation. Over the course of 8 years, the relative trophic position of
L. humile
remained high at the leading edge of an invasion front but declined, on average, behind the front as native ants disappeared. Relative to native populations, where
L. humile
is among the most carnivorous of ants, Argentine ants from California occupied lower trophic positions. These results support the hypothesis that Argentine ants shift their diet after establishment as a result of resource depletion and increasing reliance on plant-based resources, especially honeydew-producing Hemiptera. Our results demonstrate the value of long-term and biregional data in uncovering ecological effects of invasions.
An extended dynamical hydration shell around proteins
Authors: Ebbinghaus Simon , Kim Seung Joong , Heyden Matthias , Yu Xin , Heugen Udo , Gruebele Martin , Leitner David M. , Havenith Martina
Published: December 2007

The focus in protein folding has been very much on the protein backbone and sidechains. However, hydration waters make comparable contributions to the structure and energy of proteins. The coupling between fast hydration dynamics and protein dynamics is considered to play an important role in protein folding. Fundamental questions of protein hydration include, how far out into the solvent does the influence of the biomolecule reach, how is the water affected, and how are the properties of the hydration water influenced by the separation between protein molecules in solution? We show here that Terahertz spectroscopy directly probes such solvation dynamics around proteins, and determines the width of the dynamical hydration layer. We also investigate the dependence of solvation dynamics on protein concentration. We observe an unexpected nonmonotonic trend in the measured terahertz absorbance of the five helix bundle protein λ
6–85
* as a function of the protein: water molar ratio. The trend can be explained by overlapping solvation layers around the proteins. Molecular dynamics simulations indicate water dynamics in the solvation layer around one protein to be distinct from bulk water out to ≈10 Å. At higher protein concentrations such that solvation layers overlap, the calculated absorption spectrum varies nonmonotonically, qualitatively consistent with the experimental observations. The experimental data suggest an influence on the correlated water network motion beyond 20 Å, greater than the pure structural correlation length usually observed.
Endogenous circadian rhythm in human motor activity uncoupled from circadian influences on cardiac dynamics
Authors: Ivanov Plamen Ch. , Hu Kun , Hilton Michael F. , Shea Steven A. , Stanley H. Eugene
Published: December 2007

The endogenous circadian pacemaker influences key physiologic functions, such as body temperature and heart rate, and is normally synchronized with the sleep/wake cycle. Epidemiological studies demonstrate a 24-h pattern in adverse cardiovascular events with a peak at ≈10 a.m. It is unknown whether this pattern in cardiac risk is caused by a day/night pattern of behaviors, including activity level and/or influences from the internal circadian pacemaker. We recently found that a scaling index of cardiac vulnerability has an endogenous circadian peak at the circadian phase corresponding to ≈10 a.m., which conceivably could contribute to the morning peak in cardiac risk. Here, we test whether this endogenous circadian influence on cardiac dynamics is caused by circadian-mediated changes in motor activity or whether activity and heart rate dynamics are decoupled across the circadian cycle. We analyze high-frequency recordings of motion from young healthy subjects during two complementary protocols that decouple the sleep/wake cycle from the circadian cycle while controlling scheduled behaviors. We find that static activity properties (mean and standard deviation) exhibit significant circadian rhythms with a peak at the circadian phase corresponding to 5–9 p.m. (≈9 h later than the peak in the scale-invariant index of heartbeat fluctuations). In contrast, dynamic characteristics of the temporal scale-invariant organization of activity fluctuations (long-range correlations) do not exhibit a circadian rhythm. These findings suggest that endogenous circadian-mediated activity variations are not responsible for the endogenous circadian rhythm in the scale-invariant structure of heartbeat fluctuations and likely do not contribute to the increase in cardiac risk at ≈10 a.m.
Folding trajectories of human dihydrofolate reductase inside the GroEL–GroES chaperonin cavity and free in solution
Authors: Horst Reto , Fenton Wayne A. , Englander S. Walter , Wüthrich Kurt , Horwich Arthur L.
Published: December 2007

The chaperonin GroEL binds non-native polypeptides in an open ring via hydrophobic contacts and then, after ATP and GroES binding to the same ring as polypeptide, mediates productive folding in the now hydrophilic, encapsulated
cis
chamber. The nature of the folding reaction in the c
is
cavity remains poorly understood. In particular, it is unclear whether polypeptides take the same route to the native state in this cavity as they do when folding spontaneously free in solution. Here, we have addressed this question by using NMR measurements of the time course of acquisition of amide proton exchange protection of human dihydrofolate reductase (DHFR) during folding in the presence of methotrexate and ATP either free in solution or inside the stable cavity formed between a single ring variant of GroEL, SR1, and GroES. Recovery of DHFR refolded by the SR1/GroES-mediated reaction is 2-fold higher than in the spontaneous reaction. Nevertheless, DHFR folding was found to proceed by the same trajectories inside the
cis
folding chamber and free in solution. These observations are consistent with the description of the chaperonin chamber as an “Anfinsen cage” where polypeptide folding is determined solely by the amino acid sequence, as it is in solution. However, if misfolding occurs in the confinement of the chaperonin cavity, the polypeptide chain cannot undergo aggregation but rather finds its way back to a productive pathway in a manner that cannot be accomplished in solution, resulting in the observed high overall recovery.
Mutation of an A-kinase-anchoring protein causes long-QT syndrome
Authors: Chen Lei , Marquardt Michelle L. , Tester David J. , Sampson Kevin J. , Ackerman Michael J. , Kass Robert S.
Published: December 2007

A-kinase anchoring proteins (AKAPs) recruit signaling molecules and present them to downstream targets to achieve efficient spatial and temporal control of their phosphorylation state. In the heart, sympathetic nervous system (SNS) regulation of cardiac action potential duration (APD), mediated by β-adrenergic receptor (βAR) activation, requires assembly of AKAP9 (Yotiao) with the I
Ks
potassium channel α subunit (KCNQ1). KCNQ1 mutations that disrupt this complex cause type 1 long-QT syndrome (LQT1), one of the potentially lethal heritable arrhythmia syndromes. Here, we report identification of (
i
) regions on Yotiao critical to its binding to KCNQ1 and (
ii
) a single putative LQTS-causing mutation (S1570L) in
AKAP9
(Yotiao) localized to the KCNQ1 binding domain in 1/50 (2%) subjects with a clinically robust phenotype for LQTS but absent in 1,320 reference alleles. The inherited S1570L mutation reduces the interaction between KCNQ1 and Yotiao, reduces the cAMP-induced phosphorylation of the channel, eliminates the functional response of the I
Ks
channel to cAMP, and prolongs the action potential in a computational model of the ventricular cardiocyte. These reconstituted cellular consequences of the inherited S1570L-Yotiao mutation are consistent with delayed repolarization of the ventricular action potential observed in the affected siblings. Thus, we have demonstrated a link between genetic perturbations in AKAP and human disease in general and
AKAP9
and LQTS in particular.
Tumor Necrosis Factor α Regulates Responses to Nerve Growth Factor, Promoting Neural Cell Survival but Suppressing Differentiation of Neuroblastoma Cells
Authors: Takei Yoshinori , Laskey Ronald
Published: December 2007

Although nerve growth factor (NGF) promotes survival of neurons, tumor necrosis factor α (TNF-α) contributes to cell death triggered by NGF depletion, through TNF-α receptor (TNFR) 1. In contrast to this effect, TNF-α can promote neural cell survival via TNF-α receptor TNFR2. Although these findings demonstrate pivotal roles of TNF-α and NGF in cell fate decisions, cross-talk between these signaling pathways has not been clarified. We find that NGF can induce TNF-α synthesis through the nuclear factor-κB transcription factor. This provides a new basis for examining the cross-talk between NGF and TNF-α. Inhibition of TNFR2 shows opposite effects on two downstream kinases of NGF, extracellular signal-regulated kinase (Erk) and Akt. It increases Erk activation by NGF, and this increased activation induces differentiation of neuroblastoma cell lines. Reciprocally, inhibition of TNFR2 decreases Akt activation by NGF. Consistent with an essential role of Akt in survival signaling, inhibition of TNF-α signaling decreases NGF-dependent survival of neurons from rat dorsal root ganglia. Thus, NGF and NGF-induced TNF-α cooperate to activate Akt, promoting survival of normal neural cells. However, the NGF-induced TNF-α suppresses Erk activation by NGF, blocking NGF-induced differentiation of neuroblastoma cells. TNFR2 signaling could be a novel target to modulate cell responses to NGF.
Polyunsaturated Fatty Acids Influence Synaptojanin Localization to Regulate Synaptic Vesicle Recycling
Authors: Marza Esther , Long Toni , Saiardi Adolfo , Sumakovic Marija , Eimer Stefan , Hall David H. , Lesa Giovanni M.
Published: December 2007

The lipid polyunsaturated fatty acids are highly enriched in synaptic membranes, including synaptic vesicles, but their precise function there is unknown. Caenorhabditis elegans fat-3 mutants lack long-chain polyunsaturated fatty acids (LC-PUFAs); they release abnormally low levels of serotonin and acetylcholine and are depleted of synaptic vesicles, but the mechanistic basis of these defects is unclear. Here we demonstrate that synaptic vesicle endocytosis is impaired in the mutants: the synaptic vesicle protein synaptobrevin is not efficiently retrieved after synaptic vesicles fuse with the presynaptic membrane, and the presynaptic terminals contain abnormally large endosomal-like compartments and synaptic vesicles. Moreover, the mutants have abnormally low levels of the phosphoinositide phosphatase synaptojanin at release sites and accumulate the main synaptojanin substrate phosphatidylinositol 4,5-bisphosphate at these sites. Both synaptobrevin and synaptojanin mislocalization can be rescued by providing exogenous arachidonic acid, an LC-PUFA, suggesting that the endocytosis defect is caused by LC-PUFA depletion. By showing that the genes fat-3 and synaptojanin act in the same endocytic pathway at synapses, our findings suggest that LC-PUFAs are required for efficient synaptic vesicle recycling, probably by modulating synaptojanin localization at synapses.
Intraflagellar Transport and Functional Analysis of Genes Required for Flagellum Formation in Trypanosomes
Authors: Absalon Sabrina , Blisnick Thierry , Kohl Linda , Toutirais Géraldine , Doré Gwénola , Julkowska Daria , Tavenet Arounie , Bastin Philippe
Published: December 2007

Intraflagellar transport (IFT) is the bidirectional movement of protein complexes required for cilia and flagella formation. We investigated IFT by analyzing nine conventional IFT genes and five novel putative IFT genes (PIFT) in Trypanosoma brucei that maintain its existing flagellum while assembling a new flagellum. Immunostaining against IFT172 or expression of tagged IFT20 or green fluorescent protein GFP::IFT52 revealed the presence of IFT proteins along the axoneme and at the basal body and probasal body regions of both old and new flagella. IFT particles were detected by electron microscopy and exhibited a strict localization to axonemal microtubules 3–4 and 7–8, suggesting the existence of specific IFT tracks. Rapid (>3 μm/s) bidirectional intraflagellar movement of GFP::IFT52 was observed in old and new flagella. RNA interference silencing demonstrated that all individual IFT and PIFT genes are essential for new flagellum construction but the old flagellum remained present. Inhibition of IFTB proteins completely blocked axoneme construction. Absence of IFTA proteins (IFT122 and IFT140) led to formation of short flagella filled with IFT172, indicative of defects in retrograde transport. Two PIFT proteins turned out to be required for retrograde transport and three for anterograde transport. Finally, flagellum membrane elongation continues despite the absence of axonemal microtubules in all IFT/PIFT mutant.
Derlin-1 Facilitates the Retro-Translocation of Cholera Toxin
Authors: Bernardi Kaleena M. , Forster Michele L. , Lencer Wayne I. , Tsai Billy
Published: December 2007

Cholera toxin (CT) intoxicates cells by using its receptor-binding B subunit (CTB) to traffic from the plasma membrane to the endoplasmic reticulum (ER). In this compartment, the catalytic A1 subunit (CTA1) is unfolded by protein disulfide isomerase (PDI) and retro-translocated to the cytosol where it triggers a signaling cascade, leading to secretory diarrhea. How CT is targeted to the site of retro-translocation in the ER membrane to initiate translocation is unclear. Using a semipermeabilized-cell retro-translocation assay, we demonstrate that a dominant-negative Derlin-1-YFP fusion protein attenuates the ER-to-cytosol transport of CTA1. Derlin-1 interacts with CTB and the ER chaperone PDI as assessed by coimmunoprecipitation experiments. An in vitro membrane-binding assay showed that CTB stimulated the unfolded CTA1 chain to bind to the ER membrane. Moreover, intoxication of intact cells with CTB stabilized the degradation of a Derlin-1–dependent substrate, suggesting that CT uses the Derlin-1 pathway. These findings indicate that Derlin-1 facilitates the retro-translocation of CT. CTB may play a role in this process by targeting the holotoxin to Derlin-1, enabling the Derlin-1–bound PDI to unfold the A1 subunit and prepare it for transport.
Coordinated Vascular Endothelial Growth Factor Expression and Signaling During Skeletal Myogenic Differentiation
Authors: Bryan Brad A. , Walshe Tony E. , Mitchell Dianne C. , Havumaki Josh S. , Saint-Geniez Magali , Maharaj Arindel S. , Maldonado Angel E. , D'Amore Patricia A.
Published: December 2007

Angiogenesis is largely controlled by hypoxia-driven transcriptional up-regulation and secretion of vascular endothelial growth factor (VEGF) and its binding to the endothelial cell tyrosine receptor kinases, VEGFR1 and VEGFR2. Recent expression analysis suggests that VEGF is expressed in a cell-specific manner in normoxic adult tissue; however, the transcriptional regulation and role of VEGF in these tissues remains fundamentally unknown. In this report we demonstrate that VEGF is coordinately up-regulated during terminal skeletal muscle differentiation. We reveal that this regulation is mediated in part by MyoD homo- and hetero-dimeric transcriptional mechanisms. Serial deletions of the VEGF promoter elucidated a region containing three tandem CANNTG consensus MyoD sites serving as essential sites of direct interaction for MyoD-mediated up-regulation of VEGF transcription. VEGF-null embryonic stem (ES) cells exhibited reduced myogenic differentiation compared with wild-type ES cells, suggesting that VEGF may serve a role in skeletal muscle differentiation. We demonstrate that VEGFR1 and VEGFR2 are expressed at low levels in myogenic precursor cells and are robustly activated upon VEGF stimulation and that their expression is coordinately regulated during skeletal muscle differentiation. VEGF stimulation of differentiating C2C12 cells promoted myotube hypertrophy and increased myogenic differentiation, whereas addition of sFlt1, a VEGF inhibitor, resulted in myotube hypotrophy and inhibited myogenic differentiation. We further provide evidence indicating VEGF-mediated myogenic marker expression, mitogenic activity, migration, and prosurvival functions may contribute to increased myogenesis. These data suggest a novel mechanism whereby VEGF is coordinately regulated as part of the myogenic differentiation program and serves an autocrine function regulating skeletal myogenesis.
Genetic evidence for co-occurrence of chromosomal and thermal sex-determining systems in a lizard
Authors: Radder Rajkumar S , Quinn Alexander E , Georges Arthur , Sarre Stephen D , Shine Richard
Published: December 2007

An individual's sex depends upon its genes (genotypic sex determination or GSD) in birds and mammals, but reptiles are more complex: some species have GSD whereas in others, nest temperatures determine offspring sex (temperature-dependent sex determination). Previous studies suggested that montane scincid lizards (
Bassiana duperreyi
, Scincidae) possess both of these systems simultaneously: offspring sex is determined by heteromorphic sex chromosomes (XX–XY system) in most natural nests, but sex ratio shifts suggest that temperatures override chromosomal sex in cool nests to generate phenotypically male offspring even from XX eggs. We now provide direct evidence that incubation temperatures can sex-reverse genotypically female offspring, using a DNA sex marker. Application of exogenous hormone to eggs also can sex-reverse offspring (oestradiol application produces XY as well as XX females). In conjunction with recent work on a distantly related lizard taxon, our study challenges the notion of a fundamental dichotomy between genetic and thermally determined sex determination, and hence the validity of current classification schemes for sex-determining systems in reptiles.
Identification of 19 Polymorphic Major Outer Membrane Protein Genes and Their Immunogenic Peptides inEhrlichia ewingiifor Use in a Serodiagnostic Assay
Authors: Zhang Chunbin , Xiong Qingming , Kikuchi Takane , Rikihisa Yasuko
Published: December 2007

Ehrlichia ewingii, a tick-transmitted rickettsia previously known only as a canine pathogen, was recently recognized as a human pathogen.E. ewingiihas yet to be cultivated, and there is no serologic test available to diagnoseE. ewingiiinfection. Previously, a fragment (505 bp) of a singleE. ewingiigene homologous to 1 of 22 genes encodingEhrlichia chaffeensisimmunodominant major outer membrane proteins 1 (OMP-1s)/P28s was identified. The purposes of the present study were to (i) determine theE. ewingii omp-1gene family, (ii) determine each OMP-1-specific peptide, and (iii) analyze all OMP-1 synthesized peptides for antigenicity. Using nested touchdown PCR and a primer walking strategy, we found 19omp-1paralogs inE. ewingii. These genes are arranged in tandem downstream oftr1and upstream ofsecAin a 24-kb genomic region. Predicted molecular masses of the 19 matureE. ewingiiOMP-1s range from 25.1 to 31.3 kDa, with isoelectric points of 5.03 to 9.80. Based on comparative sequence analyses among OMP-1s fromE. ewingiiand three otherEhrlichiaspp., eachE. ewingiiOMP-1 oligopeptide that was predicted to be antigenic, bacterial surface exposed, unique in comparison to the otherE. ewingiiOMP-1s, and distinct from those of otherEhrlichiaspp. was synthesized for use in an enzyme-linked immunosorbent assay. Plasmas from experimentallyE. ewingii-infected dogs reacted significantly with most of the OMP-1-specific peptides, indicating that multiple OMP-1s were expressed and immunogenic in infected dogs. The results support the utility of the tailored OMP-1 peptides asE. ewingiiserologic test antigens.
Simultaneous Detection ofChlamydophila pneumoniaeandMycoplasma pneumoniaeby Use of Molecular Beacons in a Duplex Real-Time PCR
Authors: Gullsby Karolina , Storm Martin , Bondeson Kåre
Published: December 2007

A real-time PCR was designed for detection ofChlamydophila pneumoniaeandMycoplasma pneumoniaesuch that each pathogen could be detected in a single tube and differentiated using molecular beacons marked with different fluorochromes. This duplex PCR, targeting the P1 adhesion gene forM. pneumoniaeand theompAgene forC. pneumoniae, was compared with two conventional PCR assays targeting the 16S rRNA gene and theompAgene. A total of 120 clinical throat and nasopharyngeal swab samples were tested. DNA extraction was performed using an alkali denaturation/neutralization method, and real-time amplification, detection, and data analysis were performed using a Rotor-Gene 2000 real-time rotary analyzer (Corbett Life Science, Sydney, Australia). Using conventional PCR as a reference in an analysis of 120 samples, 13 of 14 samples positive forC. pneumoniaewere detected by the novel real-time PCR. In an analysis ofM. pneumoniae, 22 samples were positive in the conventional PCR and the novel assay detected 24 positive samples. When using the conventional PCR as a reference, sensitivity and specificity were 93% and 100%, respectively, forC. pneumoniaeand 100% and 98%, respectively, forM. pneumoniae. With an overall agreement of 98.8%, this suggests that performance of the new duplex real-time PCR is comparable to that of conventional PCR.
Interaction between the Human Immunodeficiency Virus Type 1 Gag Matrix Domain and Phosphatidylinositol-(4,5)-Bisphosphate Is Essential for Efficient Gag Membrane Binding
Authors: Chukkapalli Vineela , Hogue Ian B. , Boyko Vitaly , Hu Wei-Shau , Ono Akira
Published: December 2007

Human immunodeficiency virus type 1 (HIV-1) particle assembly mediated by the viral structural protein Gag occurs predominantly on the plasma membrane (PM). Although it is known that the matrix (MA) domain of Gag plays a major role in PM localization, molecular mechanisms that determine the location of assembly remain to be elucidated. We observed previously that overexpression of polyphosphoinositide 5-phosphatase IV (5ptaseIV) that depletes PM phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P
2
] impairs virus particle production and redirects processed Gag to intracellular compartments. In this study, we examined the impact of PI(4,5)P
2
depletion on the subcellular localization of the entire Gag population using Gag-fluorescent protein chimeras. Upon 5ptaseIV overexpression, in addition to perinuclear localization, Gag also showed a hazy cytosolic signal, suggesting that PI(4,5)P
2
depletion impairs Gag membrane binding. Indeed, Gag was less membrane bound in PI(4,5)P
2
-depleted cells, as assessed by biochemical analysis. These observations are consistent with the hypothesis that Gag interacts with PI(4,5)P
2
. To examine a putative Gag interaction with PI(4,5)P
2
, we developed an in vitro binding assay using full-length myristoylated Gag and liposome-associated PI(4,5)P
2
. Using this assay, we observed that PI(4,5)P
2
significantly enhances liposome binding of wild-type Gag. In contrast, a Gag derivative lacking MA did not require PI(4,5)P
2
for efficient liposome binding. To analyze the involvement of MA in PI(4,5)P
2
binding further, we examined MA basic amino acid substitution mutants. These mutants, previously shown to localize in perinuclear compartments, bound PI(4,5)P
2
-containing liposomes weakly. Altogether, these results indicate that HIV-1 Gag binds PI(4,5)P
2
on the membrane and that the MA basic domain mediates this interaction.
The Programmed Death-1 and Interleukin-10 Pathways Play a Down-Modulatory Role in LP-BM5 Retrovirus-Induced Murine Immunodeficiency Syndrome
Authors: Green Kathy A. , Okazaki Taku , Honjo Tasuku , Cook W. James , Green William R.
Published: December 2007

Pathology due to the immune system's response to viral infections often represents a delicate balance between inhibition of viral pathogenesis and regulation of protective immunity. In susceptible C57BL/6 (B6) mice, the murine retroviral isolate LP-BM5 induces splenomegaly, hypergammaglobulinemia, profound B- and T-cell immunodeficiency, and increased susceptibility to opportunistic pathogens and terminal B-cell lymphomas. Here, we report that B6.PD-1 (programmed death-1) and B6.IL-10 knockout mice are substantially more susceptible to LP-BM5-induced disease than wild-type B6 mice. LP-BM5-infected B6.PD-1−/−mice developed more severe splenomegaly, hypergammaglobulinemia, and immunodeficiency than infected B6 mice: PD-1−/−mice are more susceptible to lower doses of LP-BM5 and show more exaggerated disease early postinfection. LP-BM5-infected B6.IL-10−/−mice also develop exaggerated LP-BM5-induced disease, compared to B6 mice, without a significant change in the retroviral load. By reciprocal reconstitution experiments, comparing wild-type versus PD-1−/−sources of the requisite cells for LP-BM5 pathogenesis—CD4 T and B cells, PD-1+B cells appear to be crucial in the normal limitation of LP-BM5-induced disease in B6 mice. Also, infected B6 mice have increased CD11b+spleen cells that express interleukin-10 (IL-10). However, PD-1−/−mice, though showing an even greater expansion of CD11b+cells after LP-BM5 inoculation, did not show an equivalent increase in IL-10-producing cells. Thus, it appears that PD-1/PD-L interactions and IL-10 are primarily important in moderating the effects of LP-BM5-induced disease in B6 mice.
Identification of Cellular Proteins That Maintain Retroviral Epigenetic Silencing: Evidence for an Antiviral Response
Authors: Poleshko Andrey , Palagin Ivan , Zhang Rugang , Boimel Pamela , Castagna Carolyn , Adams Peter D. , Skalka Anna Marie , Katz Richard A.
Published: December 2007

Integrated retroviral DNA is subject to epigenetic gene silencing, resulting in loss of expression of viral genes as well as reporter or therapeutic genes transduced by retroviral vectors. Possible mediators of such silencing include the histone deacetylase (HDAC) family of cellular proteins. We previously isolated HeLa cell populations that harbored silent avian sarcoma virus-based green fluorescent protein (GFP) vectors that could be reactivated by treatment with HDAC inhibitors. Here, we developed a small interfering RNA (siRNA)-based approach to identify specific host factors that participate in the maintenance of silencing. Knockdown of HDAC1, the transcriptional repressor Daxx (a binding partner of HDAC1), or heterochromatin protein 1 gamma resulted in robust and specific GFP reporter gene reactivation. Analyses of cell clones and diverse GFP vector constructs revealed that the roles of HDAC1 and Daxx in retroviral silencing are largely independent of the integration site or the promoter controlling the silent GFP reporter gene. Previous findings from our laboratory and those of others have suggested that Daxx and HDAC proteins may act broadly as part of an antiviral response to repress viral gene transcription. Expression of presumptive viral “countermeasure” proteins that are known to inhibit Daxx or HDACs (pp71, IE2, and Gam1) resulted in the reactivation of GFP reporter gene expression. This study has identified individual host factors that maintain retroviral silencing and supports the proposal that these factors participate in an antiviral response. Furthermore, our results indicate that siRNAs can be used as specific reagents to interrupt the maintenance of epigenetic silencing.
Inhibition of Hepadnavirus Reverse Transcriptase-ε RNA Interaction by Porphyrin Compounds
Authors: Lin Li , Hu Jianming
Published: December 2007

The hepatitis B virus (HBV) reverse transcriptase (RT) plays a multitude of fundamental roles in the viral life cycle and is the key target in the development of anti-HBV chemotherapy. We report here that the endogenous small molecule iron protoporphyrin IX (hemin) and several related porphyrin compounds potently blocked a critical RT interaction with the viral RNA packaging signal/origin of replication, called ε. As RT-ε interaction is essential for the initiation of viral reverse transcription, which is primed by RT itself (protein priming), the porphyrin compounds dramatically suppressed the protein-priming reaction. Further studies demonstrated that these compounds could target the unique N-terminal domain of the RT protein, the so-called terminal protein. Hemin and related porphyrin compounds thus represent a novel class of agents that can block HBV RT functions through a mechanism and target that are completely distinct from those of existing anti-HBV drugs.
On possible forms of relationship between magmatism and tectogenesis
Authors: BELOUSSOV VLADIMIR VLADIMIROVICH
Published: December 2007

The appearance of magmatic rocks on the surface or near it is the result of a certain chain of processes, a list of which might look like the following:
(a)
a partial or complete melting of the upper mantle and the formation of a primary magmatic emulsion;
(b)
rise of the primary magmatic emulsion;
(c)
isolation of basaltic asthenoliths;
(d)
rising of asthenoliths;
(e)
a change in composition of the primary magma as a result of differentiation, assimilation and contamination;
(f)
heating of the crust, regional metamorphism, melting of rocks of the crust, gneissification and granitization.

This paper aims to give a brief survey of the probable nature of the processes mentioned above from the viewpoint of the tectonic environment in which they occur. This is the view of a tectonist concerning magmatism. The survey is confined to the continents.
A major intra-Cretaceous unconformity in eastern South Africa
Authors: KENNEDY WILLIAM JAMES , KLINGER HERBERT
Published: December 2007

The
Z
ululand
C
retaceous
succession has long been a subject of contention. Some authors (
Van Hoepen 1926
, 1929
, 1957
;
Heinz 1930
;
Venzo 1936
) have regarded it as a continuous sequence from Aptian to either Gampanian or Maastrichtian; others have followed Du Toit (1954) in questioning the presence of Turonian rocks, on regional and tectonic grounds.

We have recently examined critical exposures from the Mozambique border south to the northern Transkei (Fig. 1), as a result of which it is clear that a major unconformity exists within the Upper Cretaceous. Uppermost Cenomanian and Turonian rocks are missing, and the Coniacian progressively oversteps Middle Cenomanian to Aptian, and eventually rests on various horizons down to the Ordovician Table Mountain Sandstone.

The most important localities lie along the Umsinene River, Zululand (Fig. 2). Here, coarse clastic pre-Upper Aptian Cretaceous sediments rest on Jurassic Lembombo rhyolites and are locally overlain by Upper Aptian marine sediments. The Albian/Aptian boundary is a non-sequence, followed by an expanded succession up to the Upper Albian
Stoliczkaia dispar Zone.
The succeeding Genomanian is well-represented at Skoenberg Hill (Fig. 2), where there is a complete transition up from the Albian. The Lower Cenomanian is relatively thin, and is followed by the Middle Cenomanian fauna described by
Crick (1907)
.

The Cenomanian sediments are rather poor in fossils in the upper part and can be traced over the northern and southern flanks of Skoenberg. They are terminated sharply by an erosion surface, overlain by a thin
Trigonia
conglomerate. Below this conglomerate, silts and
Second symposium on Gondwana stratigraphy and palaeontology, South Africa, 1970
Authors: ROBINSON PAMELA LAMPLUGH
Published: December 2007

T
he
S
outhern
H
emisphere
continents and India are believed to be fragments of a former supercontinent, Gondwanaland, which broke apart in later Mesozoic times. Inevitably, those working in these regions have many problems of common interest, but there are few opportunities for Gondwana geologists to meet for discussion and exchange of information. To remedy this a series of Symposia was proposed, with meetings in each of the major fragments of Gondwanaland. The proposal was made in 1964, at a meeting of the I.U.G.S. Subcommission of Gondwana Stratigraphy held at the International Geological Congress in New Delhi. The First Symposium on Gondwana Stratigraphy and Palaeontology was held in Argentina in 1967, and was so successful that the future of these meetings was assured. The papers given at the First Symposium have been published, the majority in a single large volume published by U.N.E.S.C.O.
1
A smaller number of papers, reviews of the geology of the major regions of Gondwanaland by invited authors, was published by the I.U.G.S. Committee for the study of Geological Documentation.
2

The Second Symposium was held in South Africa in July 1970 by kind invitation of the South African Government, and was organized by the South African C.S.I.R. Scientific papers were given at two sessions, one held in Cape Town, the other in Johannesburg. Plenary papers covered various topics of general interest: Glaciations of Gondwanaland (L. A. Frakes), Palaeomagnetic data from Gondwanaland (K. M. Creer), Continental drift and palaeo-current analysis (J. J. Bigarella), Marine fossil invertebrates of the Gondwana region
The use of microplankton in resolving stratigraphical problems in the Eocene of the Isle of Wight
Authors: EATON GEOFFREY LEONARD
Published: December 2007

THE FIRST STAGE in this investigation of the microplankton (dinoflagellate cysts and acritarchs) of the Bracklesham Beds of the Isle of Wight has involved the re-examination of the classic Eocene cliff sections at Whitecliff Bay in the east and Alum Bay in the west.

Fisher’s concept of the type section of the Bracklesham Beds at Whitecliff Bay (
Fisher 1862
) formed the basis of the present study, although his interpretation of the lithological divisions has been slightly modified.

At Alum Bay the Bagshot and Bracklesham Beds have been redefined. Several breaks have been noted in the sequence, all but one of which are succeeded by a pebble bed.

Rich microplankton assemblages have been recovered from the Bracklesham Beds of both sections. Mollusca and Foraminifera are essentially restricted to the marine clays and greensands. Microplankton also occur in these sediments and in the ‘laminated beds’ (
Fisher 1862
, p. 67). This difference in distribution is particularly significant at Alum Bay where all but the highest 16 metres (52 feet) of the Bracklesham Beds were previously thought to be devoid of marine fossils.

The stratigraphical ranges of selected microplankton species have been used to define five microplankton zones in the type section of the Bracklesham Beds at Whitecliff Bay. All five zones have been recognized in the redefined Bracklesham Beds at Alum Bay, and the divisions within the Bracklesham Beds of both sections have been correlated for the first time.

As a result of this correlation the following conclusions were reached concerning the section