bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary teacher identity, commitment and career in performative school cultures
Authors: Troman Geoff
Published: August 2008

The research reported here maps changes in primary teachers' identity, commitment and perspectives and subjective experiences of occupational career in the context of performative primary school cultures. The research aimed to provide in‐depth knowledge of performative school culture and teachers' subjective experiences in their work of teaching. Themes in the data reveal changed commitments and professional identities. The teachers who had an initial vocational commitment and strong service ethic were the older teachers in the sample. While some of the younger teachers expressed vocationalism in the form of wanting ‘to make a difference’, they also stressed the importance of time compatibility for family‐friendly work and child care. In the ‘highs’ and ‘lows’ of school life a number of factors supported some of the teachers' initial commitments, thus, providing ‘satisfiers’ in their work. However, some factors impacted negatively on teacher commitment. The psychic rewards of teaching provided the main basis of commitment and professional work satisfaction. Teacher strategies in performative school cultures highlighted the impact and saliency of testing regimes. There was evidence, however, of teacher mediation of policy and their investment in a more creative professional identity in their involvement in nurturing programmes and creative projects. Whether the schools and teachers developed creative approaches to increase test scores or to ameliorate the worst effects of testing they demanded increased effort and commitment from the teachers. Teachers in the contemporary context, who had in many cases experienced a career in another occupation prior to teaching, seemed much more adept and realistic in both recognising and managing their range of parallel commitments and identities. They have become more strategic and political in defending their self‐identities. Some evidence suggests their priorities have been to hold on to their humanistic values and their self‐esteem, while adjusting their commitments.
Creativity and performativity: The case of further education
Authors: Simmons Robin , Thompson Ron
Published: August 2008

This article examines the circumstances affecting creative teaching and learning within the specific context of English further education (FE)—a sector which has proved to be particularly fertile ground for performativity. Beginning with an analysis of notions of creativity in education and a description of the peculiar history and policy context of FE, the article problematises the relationship between representations of creativity and the current situation of teachers and learners. Drawing on a range of empirical studies and policy analyses, it is argued that FE is increasingly positioned at the ‘lower end’ of a largely class‐based division of post‐compulsory education in England. In such a division, the authors argue, meaningful creativity is difficult to achieve. Within the performative context of FE, attempts to interpret official discourse on creativity may only serve to reproduce and exacerbate existing inequalities in education.
Vezf1 regulates genomic DNA methylation through its effects on expression of DNA methyltransferase Dnmt3b
Authors: Gowher Humaira , Stuhlmann Heidi , Felsenfeld Gary
Published: August 2008

The zinc finger protein vascular endothelial zinc finger 1 (Vezf1) has been implicated in the development of the blood vascular and lymphatic system in mice, and has been characterized as a transcriptional activator in some systems. The chicken homolog, BGP1, has binding sites in theβ-globinlocus, including the upstream insulator element. We report that in a mouse embryonic stem cell line deletion of both copies ofVezf1results in loss of DNA methylation at widespread sites in the genome, including Line1 elements and minor satellite repeats, some imprinted genes, and several CpG islands. Loss of methylation appears to arise from a substantial decrease in the abundance of the de novo DNA methyltransferase, Dnmt3b. These results suggest that naturally occurring mutations inVezf1/BGP1might have widespread effects on DNA methylation patterns and therefore on epigenetic regulation of gene expression.
Inhibitor of differentiation 4 drives brain tumor-initiating cell genesis through cyclin E and notch signaling
Authors: Jeon Hye-Min , Jin Xun , Lee Joong-Seob , Oh Se-Yeong , Sohn Young-Woo , Park Hyo-Jung , Joo Kyeung Min , Park Woong-Yang , Nam Do-Hyun , DePinho Ronald A. , Chin Lynda , Kim Hyunggee
Published: August 2008

Cellular origins and genetic factors governing the genesis and maintenance of glioblastomas (GBM) are not well understood. Here, we report a pathogenetic role of the developmental regulator Id4 (inhibitor of differentiation 4) in GBM. In primary murine Ink4a/Arf−/− astrocytes, and human glioma cells, we provide evidence that enforced Id4 can drive malignant transformation by stimulating increased cyclin E to produce a hyperproliferative profile and by increased Jagged1 expression with Notch1 activation to drive astrocytes into a neural stem-like cell state. Thus, Id4 plays an integral role in the transformation of astrocytes via its combined actions on two-key cell cycle and differentiation regulatory molecules.
A comprehensive synthetic genetic interaction network governing yeast histone acetylation and deacetylation
Authors: Lin Yu-yi , Qi Yan , Lu Jin-ying , Pan Xuewen , Yuan Daniel S. , Zhao Yingming , Bader Joel S. , Boeke Jef D.
Published: August 2008

Histone acetylation and deacetylation are among the principal mechanisms by which chromatin is regulated during transcription, DNA silencing, and DNA repair. We analyzed patterns of genetic interactions uncovered during comprehensive genome-wide analyses in yeast to probe how histone acetyltransferase (HAT) and histone deacetylase (HDAC) protein complexes interact. The genetic interaction data unveil an underappreciated role of HDACs in maintaining cellular viability, and led us to show that deacetylation of the histone variant Htz1p at Lys 14 is mediated by Hda1p. Studies of the essential nucleosome acetyltransferase of H4 (NuA4) revealed acetylation-dependent protein stabilization of Yng2p, a potential nonhistone substrate of NuA4 and Rpd3C, and led to a new functional organization model for this critical complex. We also found that DNA double-stranded breaks (DSBs) result in local recruitment of the NuA4 complex, followed by an elaborate NuA4 remodeling process concomitant with Rpd3p recruitment and histone deacetylation. These new characterizations of the HDA and NuA4 complexes demonstrate how systematic analyses of genetic interactions may help illuminate the mechanisms of intricate cellular processes.
Encoding NF-κB temporal control in response to TNF: distinct roles for the negative regulators IκBα and A20
Authors: Werner Shannon L. , Kearns Jeffrey D. , Zadorozhnaya Victoria , Lynch Candace , O’Dea Ellen , Boldin Mark P. , Ma Averil , Baltimore David , Hoffmann Alexander
Published: August 2008

TNF-induced NF-κB activity shows complex temporal regulation whose different phases lead to distinct gene expression programs. Combining experimental studies and mathematical modeling, we identify two temporal amplification steps—one determined by the obligate negative feedback regulator IκBα—that define the duration of the first phase of NF-κB activity. The second phase is defined by A20, whose inducible expression provides for a rheostat function by which other inflammatory stimuli can regulate TNF responses. Our results delineate the nonredundant functions implied by the knockout phenotypes ofiκbαanda20, and identify the latter as a signaling cross-talk mediator controlling inflammatory and developmental responses.
A highly conserved molecular switch binds MSY-3 to regulate myogenin repression in postnatal muscle
Authors: Berghella Libera , De Angelis Luciana , De Buysscher Tristan , Mortazavi Ali , Biressi Stefano , Forcales Sonia V. , Sirabella Dario , Cossu Giulio , Wold Barbara J.
Published: August 2008

Myogenin is the dominant transcriptional regulator of embryonic and fetal muscle differentiation and during maturation is profoundly down-regulated. We show that a highly conserved 17-bp DNA cis-acting sequence element located upstream of the myogenin promoter (myogHCE) is essential for postnatal repression of myogenin in transgenic animals. We present multiple lines of evidence supporting the idea that repression is mediated by the Y-box protein MSY-3. Electroporation in vivo shows that myogHCE and MSY-3 are required for postnatal repression. We further show that, in the C2C12 cell culture system, ectopic MSY-3 can repress differentiation, while reduced MSY-3 promotes premature differentiation. MSY-3 binds myogHCE simultaneously with the homeodomain protein Pbx in postnatal innervated muscle. We therefore propose a model in which the myogHCE motif operates as a switch by specifying opposing functions; one that was shown previously is regulated by MyoD and Pbx and it specifies a chromatin opening, gene-activating function at the time myoblasts begin to differentiate; the other includes MYS-3 and Pbx, and it specifies a repression function that operates during and after postnatal muscle maturation in vivo and in myoblasts before they begin to differentiate.
Transcription in the nucleus and mRNA decay in the cytoplasm are coupled processes
Authors: Goler-Baron Vicky , Selitrennik Michael , Barkai Oren , Haimovich Gal , Lotan Rona , Choder Mordechai
Published: August 2008

Maintaining appropriate mRNAs levels is vital for any living cell. mRNA synthesis in the nucleus by RNA polymerase II core enzyme (Pol II) and mRNA decay by cytoplasmic machineries determine these levels. Yet, little is known about possible cross-talk between these processes. The yeast Rpb4/7 is a nucleo-cytoplasmic shuttling heterodimer that interacts with Pol II and with mRNAs and is required for mRNA decay in the cytoplasm. Here we show that interaction of Rpb4/7 with mRNAs and eventual decay of these mRNAs in the cytoplasm depends on association of Rpb4/7 with Pol II in the nucleus. We propose that, following its interaction with Pol II, Rpb4/7 functions in transcription, interacts with the transcript cotranscriptionally and travels with it to the cytoplasm to stimulate mRNA decay. Hence, by recruiting Rpb4/7, Pol II governs not only transcription but also mRNA decay.
An MCMC algorithm for haplotype assembly from whole-genome sequence data
Authors: Bansal Vikas , Halpern Aaron L. , Axelrod Nelson , Bafna Vineet
Published: August 2008

In comparison to genotypes, knowledge about haplotypes (the combination of alleles present on a single chromosome) is much more useful for whole-genome association studies and for making inferences about human evolutionary history. Haplotypes are typically inferred from population genotype data using computational methods. Whole-genome sequence data represent a promising resource for constructing haplotypes spanning hundreds of kilobases for an individual. In this article, we propose a Markov chain Monte Carlo (MCMC) algorithm, HASH (haplotype assembly for single human), for assembling haplotypes from sequenced DNA fragments that have been mapped to a reference genome assembly. The transitions of the Markov chain are generated using min-cut computations on graphs derived from the sequenced fragments. We have applied our method to infer haplotypes using whole-genome shotgun sequence data from a recently sequenced human individual. The high sequence coverage and presence of mate pairs result in fairly long haplotypes (N50 length ∼ 350 kb). Based on comparison of the sequenced fragments against the individual haplotypes, we demonstrate that the haplotypes for this individual inferred using HASH are significantly more accurate than the haplotypes estimated using a previously proposed greedy heuristic and a simple MCMC method. Using haplotypes from the HapMap project, we estimate the switch error rate of the haplotypes inferred using HASH to be quite low, ∼1.1%. Our Markov chain Monte Carlo algorithm represents a general framework for haplotype assembly that can be applied to sequence data generated by other sequencing technologies. The code implementing the methods and the phased individual haplotypes can be downloaded from http://www.cse.ucsd.edu/users/vibansal/HASH/.
Global organization of replication time zones of the mouse genome
Authors: Farkash-Amar Shlomit , Lipson Doron , Polten Andreas , Goren Alon , Helmstetter Charles , Yakhini Zohar , Simon Itamar
Published: August 2008

The division of genomes into distinct replication time zones has long been established. However, an in-depth understanding of their organization and their relationship to transcription is incomplete. Taking advantage of a novel synchronization method (“baby machine”) and of genomic DNA microarrays, we have, for the first time, mapped replication times of the entire mouse genome at a high temporal resolution. Our data revealed that although most of the genome has a distinct time of replication either early, middle, or late S phase, a significant portion of the genome is replicated asynchronously. Analysis of the replication map revealed the genomic scale organization of the replication time zones. We found that the genomic regions between early and late replication time zones often consist of extremely large replicons. Analysis of the relationship between replication and transcription revealed that early replication is frequently correlated with the transcription potential of a gene and not necessarily with its actual transcriptional activity. These findings, along with the strong conservation found between replication timing in human and mouse genomes, emphasize the importance of replication timing in transcription regulation.
The PAS Reaction for Staining Cell Walls
Authors: Baum Stuart
Published: August 2008

INTRODUCTION

The periodic acid Schiff (PAS) reaction is useful for looking at cell walls, especially in meristematic tissues. Total carbohydrates of insoluble polysaccharides (e.g., starch and cellulose) stain magenta to purplish red. Toluidine blue O or fast green is routinely used as a counterstain to improve contrast. In the gynoecium of the Arabidopsis flower, the transmitting tract cells are made of acid proteoglycans and acid glycoproteins. The cell walls of these cells should be stained with Alcian Blue instead of using the PAS reaction. Alcian Blue, which stains the walls a dark blue, can be used alone or as a counterstain with the PAS reaction to highlight cell walls that do not react with Alcian Blue.
Analyzing DNA Replication III: Antibody Labeling of Incorporated Bromodeoxyuridine (BrdU) in Tissues and Cells: Figure 1.
Authors: Jackson Dean , Cook Peter R.
Published: August 2008

INTRODUCTION

The number of cells traversing the cell cycle and the rate of progression through it provide important indices of cell growth and tumorigenicity. S-phase cells can also be identified by their high content of DNA polymerase and proliferating cell nuclear antigen, a component of the leading-strand polymerase. Although both these markers can be detected rapidly and conveniently using the appropriate antibodies, neither are found exclusively in S-phase cells. Immunolabeling after incorporation of modified DNA precursors (e.g., 5-bromodeoxyuridine [BrdU, bromodeoxyuridine]) allows more rapid and precise detection of cells in S-phase of the cell cycle. BrdU is phosphorylated by cells to give BrdUTP, and this precursor is incorporated into DNA instead of deoxythimidine triphosphate. In living cells, BrdU is incorporated into replication sites that can then be detected using fluorochrome or enzyme-coupled antibodies. Alternatively, DNA synthesis sites can be labeled at high resolution by incubating cells with analogs of the natural precursors of DNA. After fixation to preserve nuclear morphology, the DNA duplex is denatured to allow antibodies access to the BrdU. Cells labeled in this way either in vivo or in vitro display a few hundred discrete nuclear sites early in S-phase, with distinct patterns of DNA replication that are characteristic of different stages of S-phase. This protocol describes two commonly used methods of denaturation, as well as techniques for antibody labeling of mounted tissues and encapsulated cells.
In Vitro Assays for the Extracellular Matrix Protein-Regulated Extravasation Process
Authors: Ma Chaoyu , Wang Xiao-Fan
Published: August 2008

INTRODUCTION

Extravasation, the process by which circulating tumor cells pass through the blood vessel wall, is a critical step of metastasis. Extracellular matrix (ECM) proteins secreted by the cancer cells are likely to play an interactive role in the dynamic interaction between cancer cells and endothelial cells during the extravasation process. This protocol describes two in vitro assays, the transendothelial cell migration (TEM) assay and the vascular permeability assay, which are used to demonstrate the involvement of ECM proteins in cancer cell extravasation. Both assays employ primary human umbilical vein endothelial cells (HUVEC) to reconstitute a vessel wall (HUVEC monolayer) on a porous filter membrane within a Transwell chamber. The TEM assay examines the efficiency of cancer cells to migrate through the vessel by co-culturing the cancer cells with the endothelial monolayer. The vascular permeability assay allows the study of the impact of secreted ECM proteins on the permeability of the vessel wall by applying conditioned medium from cancer cells to the endothelial monolayer.
Whole Mount RNA In Situ Hybridization on Zebrafish Embryos: Mounting
Authors: Moens Cecilia
Published: August 2008

INTRODUCTION

This protocol describes the mounting of zebrafish embryos for observation after whole-mount in situ hybridization. Embryos can be mounted in glycerol or dehydrated and mounted in Permount, with or without the yolk. Glycerol causes less shrinkage, but is not as effective a clearing agent. Embryos mounted on the yolk should be stored in the dark and photographed immediately, because the yolks darken rapidly.
Isolation of Centrosomes from Cultured Mammalian Cells
Authors: Meigs Thomas E. , Kaplan Daniel D.
Published: August 2008

INTRODUCTION

The centrosome is a cell’s primary microtubule-organizing center. In most mammalian cells, the centrosome is composed of a pair of centrioles and surrounding pericentriolar material. The centrosome is duplicated exactly once per cell cycle such that at the onset of mitosis, a cell has two centrosomes, which serve as poles of the mitotic spindle. During cytokinesis, one centrosome is segregated to each daughter cell. This protocol describes the isolation of centrosomes from asynchronous cells, and thus the purified material will consist primarily of interphase centrosomes. Isolated centrosomes can be used in a variety of assays, including studies of microtubule function and the identification of centrosome-associated proteins and their interactions.
Imaging Calcium Dynamics Using Targeted Recombinant Aequorins
Authors: Pozzan Tullio , Rizzuto Rosario
Published: August 2008

INTRODUCTION

Aequorin is a small protein produced by the genus Aequorea that was widely used in the 1960s and 1970s as a probe to measure Ca2+ in living cells. The invention of the carboxylate Ca2+ indicators, which are much simpler to load into intact living cells and to calibrate and image at the single-cell level, has led most groups to abandon aequorin. Yet, this latter Ca2+ indicator still offers some advantages over the fluorescent probes. In particular, the use of molecular biological techniques for expressing recombinant aequorin in mammalian cells, thus eliminating the need for microinjection, has opened new possibilities for this probe. Among the new uses of aequorin, one of the most interesting is the potential for targeting it specifically to different cellular locations, thus opening the possibility of monitoring selectively the dynamics of [Ca2+] with unprecedented spatial resolution. This article briefly discusses the problems concerned with targeting aequorin to different locations, the advantages and disadvantages offered by the steep dependence of luminescence on [Ca2+], and the instruments needed to obtain reliable measurements.
Temporal resource partitioning varies with individual competitive ability: a test with Arctic charr Salvelinus alpinus visiting a feeding site from a refuge
Authors: Brännäs E.
Published: August 2008

The relationship among relative size, growth rate and diel visits into a feeding compartment were studied in Arctic charr Salvelinus alpinus, a species known for its flexible activity patterns. Individual swimming activity from a refuge compartment into an uncovered feeding compartment was studied using an automated passive integrated transponder system. Approximately half of the individuals in four groups of S. alpinus spent 70–80% of their time in the feeding compartment, regardless of the time of day. The remaining individuals spent nearly as much time (70–80%) in the feeding compartment during the night, but only spent c. 20% of their time in the feeding compartment during the day. These individuals had a lower mean ±s.d. masses (13·17 ± 4·34 g) and growth rate (daily growth coefficient, G= 0·80 ± 1·19) than those individuals that spent most of their time in the feeding compartment during the day (mass = 16·65 ± 5·73 g and G= 2·04 ± 0·81). This indicated that some smaller fish were absent from the feeding compartment during daytime, possibly to avoid aggression from larger conspecifics. In the open compartment, the aggressive interactions were more frequent in daylight than during night and always low in the covered compartment.
Acoustic telemetry to assess post‐stocking dispersal and mortality of razorback sucker Xyrauchen texanus
Authors: Karam A. P. , Kesner B. R. , Marsh P. C.
Published: August 2008

Acoustic telemetry and scuba revealed immediate and high post‐stocking mortality of razorback sucker Xyrauchen texanus in Lake Mohave, U.S.A., a Colorado River impoundment. At the conclusion of this 6 month study, only three of 19 (16%) study fish remained active. Concurrently, 20 X. texanus implanted with acoustic transmitters and held in a hatchery raceway remained healthy throughout the experiment and no transmitters were shed. Post‐stocking mortality was probably due to predation by striped bass Morone saxatilis, a piscivorous non‐native fish.
Healing of skin wounds in the African catfish Clarias gariepinus
Authors: Guerra R. R. , Santos N. P. , Cecarelli P. , Silva J. R. M. C. , Hernandez‐Blazquez F. J.
Published: August 2008

The African catfish Clarias gariepinus was used as a model for wound healing and tissue regeneration in a scale‐less fish. A temporal framework of histological and cell proliferation markers was established after wound induction in the dorsolateral cranial region, by removing the epidermal and dermal layers, including stratum adiposum (SA). Wound closure and epidermis formation was initiated within 3 h post‐procedure (hpp) with migration and concomitant proliferation of epidermal cells from the wound borders. The wound was covered by this primary epidermal front 12 hpp and fusion of the opposing epidermal fronts occurred within 24 hpp. Attachment of the newly formed epidermal layer to the underlying dermis was observed 48 hpp concomitant with a second wave of cell proliferation at the wound edge. Normal epidermal thickness within the wound was achieved 72 hpp. Formation of a basement membrane occurred by 120 hpp with concomitant emergence of the SA from the wound borders. Wound healing in C. gariepinus skin involved closure of the wound and re‐epithelization through cell migration with a single wave of early cell proliferation not documented in other species. Furthermore, covering of the wound by epithelium as well as the reappearance of the basement membrane and SA occurred sooner than in other fish species.
A validated bioenergetics model for ruffe Gymnocephalus cernuus and its application to a northern lake
Authors: Tarvainen M. , Anttalainen A. , Helminen H. , Keskinen T. , Sarvala J. , Vaahto I. , Karjalainen J.
Published: August 2008

A bioenergetics model was constructed for ruffe Gymnocephalus cernuus, and the model was used to estimate the food consumption of a native G. cernuus stock in Pyhäjärvi, a large mesotrophic lake in south‐west Finland. The parameters for the bioenergetics model were determined through laboratory experiments conducted at several temperatures between 5 and 22° C for different sized G. cernuus (from 6 to 27 g). The model was verified and validated with independent laboratory growth experiments. The validated model was applied to field data from Pyhäjärvi to estimate the food consumption of G. cernuus and its effects on the zoobenthos community during the years 2002–2004. The total annual food consumption of the G. cernuus stock ranged from 11·6 to 15·7 g m−2 (wet mass). Chironomidae was the most abundant prey, 81% of the total consumption. The annual total production of zoobenthos in Pyhäjärvi was 15·2 g m−2 (wet mass). Therefore, it can be concluded that G. cernuus stock is likely to exert a significant influence on the zoobenthos community in this lake, indicating a potential role of G. cernuus as an influential invasive species in many freshwater ecosystems in Europe and North America.
Spatial and temporal variability of juvenile spotted seatrout Cynoscion nebulosus growth in Chesapeake Bay
Authors: Smith N. G. , Jones C. M. , Van Montfrans J.
Published: August 2008

Juvenile spotted seatrout Cynoscion nebulosus growth in Chesapeake Bay was compared to growth from southerly estuaries to examine the potential for countergradient growth variation, and finer scale growth variation within Chesapeake Bay was investigated further. Because spawning and growing seasons in Chesapeake Bay are much shorter than in southern populations, and the bay population is genetically distinct, it was expected that C. nebulosus in Chesapeake Bay may exhibit faster juvenile growth than their southern counterparts. Within the bay, spatial and temporal growth patterns were examined using a repeated measures linear mixed‐effects model on individual retrospective growth histories. Juvenile C. nebulosus were collected from seagrass beds throughout Chesapeake Bay in 1997–1999 and 2002; sagittae were removed for daily growth analysis. The calculated growth rate of 1·44 mm standard length day−1 for Chesapeake Bay fish is two to three times that reported for Florida C. nebulosus. Within the bay from 1997 to 1999 (average rainfall years), growth patterns were similar with the fastest growing fish collected from seagrass beds in the central bay, followed by the eastern shore fish with intermediate growth and western shore fish that exhibited slowest growth. These results were reversed (western shore fish growth > eastern shore > central bay) in 2002 (a drought year) even though temperatures across all years were similar throughout the bay, indicating that growth may be influenced by freshwater inflows.
A physiological interpretation of pattern changes in a flatfish
Authors: Burton D.
Published: August 2008

The pattern‐related capacity for the dispersion of previously aggregated melanosomes in low concentrations (3 × 10−6 to 10−8 M) of noradrenaline in vitro was observed in melanophores from winter flounder Pseudopleuronectes americanus. With 10−8 M noradrenaline, dispersion was completed more rapidly than in controls using the incubation vehicle alone. Melanophores from white‐spot, dark‐band and general background components of the integumentary pattern displayed different ‘transition ranges’ between melanosome aggregation and dispersion in higher and lower concentrations of noradrenaline. Within each ‘transition range’ individual noradrenaline concentration decrements could result in highly variable degrees of melanosome dispersion. The relative breadth of the noradrenaline ‘transition range’ concentrations could be represented as dark bands > general background > white spots. The threshold noradrenaline concentration for dispersion was highest for the dark bands. It is concluded that these differences represent variations in the transition from melanophore α‐adrenoceptor‐mediated pigment aggregation to β‐adrenoceptor‐mediated dispersion between localized areas of the skin. Such variations in ‘transition range’ will have an important role in the expression of flatfish patterns and in their changes in colour and texture.
The effects of dietary protein:energy ratio and amino acid pattern on nitrogen utilization and excretion of rainbow trout Oncorhynchus mykiss (Walbaum)
Authors: Green J. A. , Hardy R. W.
Published: August 2008

This study was undertaken to investigate: (1) the effects of both deficiencies and excesses in essential amino acids (EAAs) from an estimated optimum dietary EAA pattern on nitrogen (N) utilization and excretion of rainbow trout Oncorhynchus mykiss, (2) the effects of dietary digestible protein (PD): digestible energy (ED) ratio (PD:ED) on N utilization and excretion of O. mykiss and (3) the potential interaction of these two factors. A 3 × 3 factorial experiment was conducted, with the two factors EAA pattern and PD:ED ratio. The three levels of EAA pattern were: (1) optimum EAA pattern, (2) 60% deficiencies in the three amino acids arginine, histidine and lysine, and (3) 60% excesses in the three amino acids arginine, histidine and leucine. The three levels of PD:ED ratio were 18, 21 and 24 g MJ−1. Amino acid deficiencies from an optimum amino acid pattern caused reductions in mean N retention of 29 to 37%, with the greatest reduction associated with the lowest PD:ED ratio, and similar substantial increases in total N and ammonia‐N excretion at all of the dietary PD:ED ratios investigated. Amino acid excesses, however, did not negatively affect N retention or excretion. Increasing PD:ED ratio was associated with decreasing N retention and increasing N excretion over the range of dietary protein and lipid levels tested. Results of this study showed that a diet with optimum dietary amino acid pattern and lowest PD:ED ratio produced the highest N retention (47% of ingested N) and the lowest total N and ammonia‐N excretion of O. mykiss.
Is peak postprandial oxygen consumption positively related to growth rate and resting oxygen consumption in a sedentary catfish Silurus meridionalis?
Authors: Fu S. J. , Cao Z. D. , Peng J. L. , Wang Y. X.
Published: August 2008

The resting oxygen consumption , postprandial and post‐exercise peak oxygen consumption of 137 juvenile southern catfish Silurus meridionalis, weighing 18·5 ± 0·8 g (mean ±s.d.), were measured at 25° C to determine whether is positively related to postprandial and post‐exercise in sedentary S. meridionalis. In addition, postprandial metabolic response [i.e. the specific dynamic action (SDA)] after a satiating meal and the growth performance as a consequence of a 3 week feeding‐growth trail were measured in 40 S. meridionalis, weighing 14·3 ± 0·2 g, at 25° C to determine whether postprandial is positively related to growth rate. Postprandial was positively correlated with , while post‐exercise was not. Both postprandial and post‐exercise were positively correlated with factorial and absolute scope. There was no significant correlation between the growth rate and postprandial in S. meridionalis. It suggested that as a sit‐and‐wait forager with low , low post‐exercise and high postprandial , the expenditure of energy for maintenance in S. meridionalis may be more closely related to digestive processes than locomotor activities.
Genetic analysis of the Hispano‐Breton heavy horse
Authors: Pérez‐Gutiérrez L. M. , De la Peña A. , Arana P.
Published: August 2008

Hispano‐Breton (HB) is a horse breed with a recent mixed ancestry. It was developed in the 1930s by crossing local mares with Breton draught horses imported from France. Nowadays it is considered to be in a vulnerable situation due to census decline. To genetically characterize the breed and to set up the basis for a conservation programme, we have employed two types of molecular markers: a 347‐bp D‐loop mitochondrial DNA (mtDNA) fragment and 13 microsatellite loci. A representative sample of 53 HB individuals was analysed together with a sample of 40 Pura Raza Española horses for comparison. Both types of markers revealed a high level of genetic diversity in the HB breed, emphasizing the importance of its conservation. The construction of a phylogenetic network with mtDNA sequences including various Iberian breeds and European heavy horses provided an overall picture of the ubiquitous appearance of HB matrilines with respect to other breeds and revealed the singularity of certain HB maternal lineages. Despite the high allelic richness found in HB horses, microsatellite analysis evidenced a certain degree of inbreeding as a consequence of the type of management generally used for local breeds.
Genetic variation in the mannosidase 2B2 gene and its association with ovulation rate in pigs
Authors: Campbell E. M. , Nonneman D. J. , Kuehn L. A. , Rohrer G. A.
Published: August 2008

Ovulation rate is an important phenotypic trait that is a critical component of litter size in pigs. Despite being moderately heritable in pigs, selection for increased ovulation rate is difficult because it is difficult to measure and is a sex‐limited trait. A QTL for ovulation rate residing on the p‐terminal end of pig chromosome 8 has been detected in a Meishan‐cross resource population. Comparative analysis of this region yielded a positional candidate gene, mannosidase 2B2 (MAN2B2), for this QTL. The entire coding region of MAN2B2 was resequenced in the Meishan and White Composite founder animals of the resource population to identify SNPs. Eleven polymorphisms that alter the protein product of MAN2B2 were discovered and tested for statistical associations with ovulation rate in three generations of the resource population. The polymorphism located at position 1574 of the mRNA (D28521:c.1574A>G) was the most significant polymorphism tested (P = 0.00005) where the additive effect of the c.1574A allele was estimated to be −0.89 ova. This polymorphism was determined to be more significantly associated with ovulation rate than the breed‐specific analysis conducted during the line‐cross QTL discovery. The c.1574A>G marker was not associated with ovulation rate in an occidental population. Therefore, either MAN2B2 has a unique epistatic interaction within the Meishan‐cross population or the c.1574A>G SNP is in linkage disequilibrium with the actual causative genetic variation in the Meishan‐cross population.
PI3K/Akt signaling as a key regulatory pathway for chondrocyte terminal differentiation
Authors: Kita Keisuke , Kimura Tohru , Nakamura Norimasa , Yoshikawa Hideki , Nakano Toru
Published: August 2008

Chondrogenesis is a well‐coordinated multi‐step differentiation process in which resting chondrocytes produce terminally differentiated hypertrophic chondrocytes through a proliferative stage. Here we show that phosphoinositide‐3 kinase (PI3K) and its major downstream molecule, Akt, a serine–threonine kinase, play pivotal roles in this process. Akt signaling was activated in resting and proliferative chondrocytes but was reduced during terminal differentiation. We adopted two chondrocyte differentiation systems to investigate the roles of PI3K/Akt signaling in chondrogenesis. First, we employed an embryonic forelimb organ culture of transgenic mice expressing an Akt‐Mer (a ligand‐binding domain of a mutated estrogen receptor) fusion protein whose kinase activity was conditionally activated by treatment with 4‐hydroxytamoxifen (4OHT). Activation of Akt signaling in embryonic chondrogenesis enhanced chondrocyte proliferation and inhibited hypertrophic differentiation, presumably due to the suppressed expression of Runx2, a transcription factor critical for chondrocyte terminal differentiation. Conversely, inhibition of PI3K by its inhibitor accelerated terminal hypertrophic differentiation, resulting in a shorter bone. Essentially the same results were obtained in a second line of experiments using human synovial stromal cells (hSSCs), which are mesenchymal progenitor cells isolated from adult joints. These findings demonstrate that PI3K/Akt signaling is a key regulator in terminal chondrocyte differentiation in both embryonic and adult chondrogenesis.
Differences and similarities in the developmental status of embryo‐derived stem cells and primordial germ cells revealed by global expression profiling
Authors: Mise Nathan , Fuchikami Takuya , Sugimoto Michihiko , Kobayakawa Satoru , Ike Fumio , Ogawa Takehiko , Tada Takashi , Kanaya Shigehiko , Noce Toshiaki , Abe Kuniya
Published: August 2008

Embryonic germ‐line cells are unipotent cells that give rise to either sperm or oocytes. However, pluripotent stem cells can be derived from primordial germ cells (PGCs) or spermatogonia, suggesting that germ‐line cells retain a capacity for pluripotency. Here, we made genome‐wide comparisons of the gene expression profiles of freshly isolated PGCs, in vitro‐formed PGCs (iPGCs), and other stem cell lines, including embryonic stem cells (ESCs), embryonic germ cells (EGCs) and germ‐line stem (GS) cells. Comparing PGC with ESC, 382 genes/transcripts were significantly up‐regulated in ESC, while 188 were elevated in PGC. This suggests that PGCs possess transcription program distinct from that of ESC, although both share expression of many pluripotency‐associated genes.

Our micro‐array analysis showed that the analyzed samples could be classified into two groups: one consisting of all the ESCs and most of EGCs, and the other containing PGC samples, iPGC, one type of female EGC and GS cells. We then identified “signature” genes for the two groups, and used them to characterize GS cells, EGC, and iPGCs, and revealed developmental status of each cell type. The relationships between PGCs and stem cells derived from embryos or germ cells are discussed in light of these findings.
Formation of cholesterol‐enriched structures by aberrant intracellular accumulation of ATP‐binding cassette transporter A1
Authors: Tanaka Arowu R. , Kano Fumi , Yamamoto Akitsugu , Ueda Kazumitsu , Murata Masayuki
Published: August 2008

ATP‐binding cassette transporter A1 (ABCA1) is a key transporter associated with excess cellular lipid efflux. Here, we report that in HEK293 cells ABCA1 functions in intracellular compartments along the endocytic pathway. Inhibition of ABCA1‐GFP degradation with proteasome inhibitors induced the internalization of ABCA1 and the formation of intracellular round‐shaped structures, designated “A1 bodies”. Importantly, cholesterol was selectively accumulated in A1 bodies, and this depended on the cholesterol efflux activity of ABCA1. Treatment with either lactacystin or acetylated LDL, which reduces proteasome activity, resulted in internalization of ABCA1 in mouse peritoneal macrophages. By performing array analysis on macrophages treated with these reagents, we identified Rab4 as a key protein involved in the internalization and aberrant accumulation of ABCA1 in HEK cells. Treatment of the cells with proteasome inhibitors inhibited the degradation of Rab4, and Rab4 over‐expression induced the formation of small A1 bodies. Furthermore, A1 bodies formation was substantially inhibited by silencing of the endogenous Rab4 gene. Taken together, our findings suggest that the endocytic ABCA1 possesses cholesterol efflux activity, and thus the cellular control of post‐endocytic sorting, retention or recycling of functional ABCA1 in the endocytic vesicles, which is in part regulated by Rab4, is important for cholesterol metabolism in living cells.
p97 homologs from Caenorhabditis elegans, CDC‐48.1 and CDC‐48.2, suppress the aggregate formation of huntingtin exon1 containing expanded polyQ repeat
Authors: Nishikori Shingo , Yamanaka Kunitoshi , Sakurai Toshihiko , Esaki Masatoshi , Ogura Teru
Published: August 2008

Polyglutamine (polyQ)‐expanded proteins are associated with cytotoxicity in some neurodegenerative disorders such as Huntington's disease. We have reported that the aggregation of the polyQ‐expanded protein is partially suppressed by co‐expression of either of two homologs of an AAA chaperone p97, CDC‐48.1 or CDC‐48.2, in Caenorhabditis elegans, but how p97 regulates the aggregation of polyQ‐expanded proteins remains unclear. Here we present direct evidence that CDC‐48.1 and CDC‐48.2 suppress the aggregation of a huntingtin (Htt) exon1 fragment containing an expanded polyQ repeat in vitro. CDC‐48.1 and CDC‐48.2 bound the Htt exon1 fragment directly, and suppressed the formation of SDS‐insoluble aggregates of Htt fragments containing 53 glutamine residues (HttQ53) independently of nucleotides. CDC‐48.1 and CDC‐48.2 also modulated the oligomeric states of HttQ53 during the aggregate formation. In the absence of CDC‐48.1 and CDC‐48.2, HttQ53 formed 70–150 kDa oligomers, whereas 300–500 kDa oligomers as well as 70–150 kDa oligomers accumulated in the presence of CDC‐48.1 and CDC‐48.2. Taken together, these results suggest that p97 plays a protective role in neurodegenerative disorders by directly suppressing the protein aggregation as a molecular chaperone.
N‐terminal region of ZW10 serves not only as a determinant for localization but also as a link with dynein function
Authors: Inoue Mamiko , Arasaki Kohei , Ueda Akihiro , Aoki Takehiro , Tagaya Mitsuo
Published: August 2008

ZW10 interacts with dynamitin, a subunit of the dynein accessory complex dynactin, and functions in termination of the spindle checkpoint during mitosis and in membrane transport between the endoplasmic reticulum (ER) and Golgi apparatus during interphase. Its associations with kinetochores and ER membranes are mediated by Zwint‐1 and RINT‐1, respectively. A previous yeast two‐hybrid study showed that the C‐terminal region of ZW10 interacts with dynamitin, and part of this region has been used as an inhibitor of ZW10 function. In the present study, we reinvestigated the interaction between ZW10 and dynamitin, and showed that the N‐terminal region of ZW10 is the major binding site for dynamitin and, like full‐length ZW10, could potentially move along microtubules to the centrosomal area in a dynein‐dynactin‐dependent manner. Competitive binding experiments demonstrated that dynamitin and RINT‐1 occupy the same N‐terminal region of ZW10 in a mutually exclusive fashion. Consistent with this, over‐expression of RINT‐1 interfered with the dynein‐dynactin‐mediated movement of ZW10 to the centrosomal area. Given that the N‐terminal region of ZW10 also interacts with Zwint‐1, this region may be important for switching partners; one partner is a determinant for localization (kinetochore and ER) and the other links ZW10 to dynein function.
Nurses’ knowledge of pharmacology behind drugs they commonly administer
Authors: Ndosi Mwidimi E , Newell Rob
Published: August 2008

Aim.  To determine if nurses had adequate pharmacology knowledge of the drugs they commonly administer.

Background.  Literature suggests that nurses have insufficient pharmacology knowledge. We also know that nurses and teachers of pharmacology are not satisfied with the amount of pharmacology taught in preregistration programmes in the UK. There is a lack of primary research on nurses’ knowledge of pharmacology for the purpose of drug administration.

Design.  We used a non‐experimental causal comparative and correlational design.

Methods.  We recruited a convenience sample of 42 nurses working in surgical wards of a foundation hospital in the North of England. Data were collected by structured interview and questionnaire methods. During the interview, the participants made a blinded selection of one out of four drugs they commonly administer and answered standard questions which focused on specific pharmacology knowledge. Their answers were given a score out of 10 (100%) to determine their actual pharmacology knowledge.

Results.  The sample comprised of 18 (42·9%) junior nurses and 24 (57·1%) senior nurses. They had a median experience of 10·87 years postregistration. Their mean knowledge score was six ranging between two and nine (SD 1·9). Only 11 (26·1%) nurses scored eight or above and the majority 24 (57·2%) scored below seven, indicating inadequate knowledge. Knowledge of the mechanism of action and drug interactions was poor. There was a correlation between knowledge and experience.

Conclusions.  The results of this study suggest that nurses have inadequate knowledge of pharmacology. The results will contribute to the evidence of nurses’ knowledge of pharmacology in the UK.

Relevance to clinical practice.  This study supports the need for supplementary pharmacology education for nurses in clinical settings, focusing on common drugs they administer. This will increase nurses’ knowledge and confidence in drug administration and safer medicines management.
Oestrogen Receptor β Contributes to the Transient Sex Difference in Tyrosine Hydroxylase Expression in the Mouse Locus Coeruleus
Authors: Pendergast J. S. , Tuesta L. M. , Bethea J. R.
Published: August 2008

Oestrogen receptors (ERs) are important for sexual differentiation of the brain. Previous studies in rats have reported that the locus coeruleus (LC), a catecholaminergic nucleus in the brain stem, is sexually dimorphic such that females have more neurones than males. We hypothesised that ERs may be important for sexual differentiation of this nucleus in mice. Because previous studies reported conflicting results regarding ER protein expression in the mouse LC, we evaluated ERα and ERβ gene expression by in situ hybridisation and the real‐time reverse transcription‐polymerase chain reaction. We demonstrated that both ERα and ERβ mRNAs are present in tyrosine hydroxylase‐immunoreactive (TH‐ir) cells in the male LC. In the female LC, ERα mRNA is present at levels similar to males, whereas ERβ mRNA expression is significantly lower than in males. Similar to rats, male mice have fewer TH‐ir cells in the LC than females at 60 days after birth, but the difference is absent at 120 days after birth when females exhibit a similar reduction in TH‐ir cells. The transient sex difference is ERβ‐dependent because is it absent in ERβ knockout mice, and is due to regulation of TH expression and not from death of TH‐ir cells. Testicular hormones produced at adolescence are necessary for the regulation of TH expression in the male LC because orchidectomy of pre‐pubertal males prevented the decrease in TH‐ir cells, whereas treatment of gonadectomised males with testosterone or its metabolite, 5α‐androstan‐3β,17β‐diol, restored the intact male phenotype. Overall, these studies indicate that ERβ is important in regulating TH expression in the mouse LC.
The vacuolar transport of aleurain‐GFP and 2S albumin‐GFP fusions is mediated by the same pre‐vacuolar compartments in tobacco BY‐2 and Arabidopsis suspension cultured cells
Authors: Miao Yansong , Li Kwun Yee , Li Hong‐Ye , Yao Xiaoqiang , Jiang Liwen
Published: August 2008

Soluble proteins reach vacuoles because they contain vacuolar sorting determinants (VSDs) that are recognized by vacuolar sorting receptor (VSR) proteins. Pre‐vacuolar compartments (PVCs), defined by VSRs and GFP‐VSR reporters in tobacco BY‐2 cells, are membrane‐bound intermediate organelles that mediate protein traffic from the Golgi apparatus to the vacuole in plant cells. Multiple pathways have been demonstrated to be responsible for vacuolar transport of lytic enzymes and storage proteins to the lytic vacuole (LV) and the protein storage vacuole (PSV), respectively. However, the nature of PVCs for LV and PSV pathways remains unclear. Here, we used two fluorescent reporters, aleurain‐GFP and 2S albumin‐GFP, that represent traffic of lytic enzymes and storage proteins to LV and PSV, respectively, to study the PVC‐mediated transport pathways via transient expression in suspension cultured cells. We demonstrated that the vacuolar transport of aleurain‐GFP and 2S albumin‐GFP was mediated by the same PVC populations in both tobacco BY‐2 and Arabidopsis suspension cultured cells. These PVCs were defined by the seven GFP‐AtVSR reporters. In wortmannin‐treated cells, the vacuolated PVCs contained the mRFP‐AtVSR reporter in their limiting membranes, whereas the soluble aleurain‐GFP or 2S albumin‐GFP remained in the lumen of the PVCs, indicating a possible in vivo relationship between receptor and cargo within PVCs.