bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environmental hypoxia influences hemoglobin subunit composition in the branchiopod crustaceanTriops longicaudatus
Authors: Guadagnoli J. A. , Braun A. M. , Roberts S. P. , Reiber C. L. 
Published: September 2005

SUMMARYHemoglobin (Hb) is a highly conserved protein that provides a vital link between environmental oxygen and its use and/or storage within an organism. While ubiquitous among vertebrates, Hb occurs frequently in invertebrate phyla as well. Many arthropod species use the copper-binding pigment hemocyanin, but unique in this phylum are the branchiopod crustaceans, which express Hb. Branchiopod Hb concentration and structure are exquisitely sensitive to environmental oxygen availability. Hemoglobin concentration and oxygen-binding affinity increase with decreasing oxygen tension in Daphnia, Artemia and Triops. The change in binding affinity is attributed to differential Hb subunit expression in Daphnia and Artemia but remains unclear for Triops. This is the first study to demonstrate developmental plasticity of Hb subunit expression in a notostracan, Triops longicaudatus, reared under conditions of varying oxygen availability. In response to variable oxygen environments, T. longicaudatus differentially express four primary Hb subunits ranging between 30 and 34 kDa, with normoxic-reared animals expressing primarily the heavier subunits, and hypoxic-reared animals expressing increased proportions of the lower molecular mass subunits. Moreover, differential Hb subunit expression is induced upon transfer of normoxic-reared adults to a hypoxic environment, such that the distribution of Hb subunits in the transferred adults becomes similar to that of hypoxic-reared animals. Two-dimensional gel electrophoresis and follow-up analyses revealed several isoforms of Hb subunits that may represent differential gene expression and/or post-translational modification. Unlike Daphnia and Artemia,the Hb hypoxic response in Triops is not reversible in that there was no significant decrease in Hb concentration or change in Hb subunit expression pattern when hypoxic-reared adults were transferred to a normoxic environment.
Olfactory coding in Drosophila larvae investigated by cross-adaptation
Authors: Boyle Jennefer , Cobb Matthew 
Published: September 2005

SUMMARY
In order to reveal aspects of olfactory coding, the effects of sensory adaptation on the olfactory responses of first-instar Drosophila melanogaster larvae were tested. Larvae were pre-stimulated with a homologous series of acetic esters (C3-C9), and their responses to each of these odours were then measured. The overall patterns suggested that methyl acetate has no specific pathway but was detected by all the sensory pathways studied here, that butyl and pentyl acetate tended to have similar effects to each other and that hexyl acetate was processed separately from the other odours. In a number of cases, cross-adaptation transformed a control attractive response into a repulsive response; in no case was an increase in attractiveness observed. This was investigated by studying changes in dose-response curves following pre-stimulation. These findings are discussed in light of the possible intra- and intercellular mechanisms of adaptation and the advantage of altered sensitivity for the larva.
Biological Variation of Vitamins in Blood of Healthy Individuals
Authors: Talwar Dinesh K , Azharuddin Mohammed K , Williamson Cathy , Teoh Yee Ping , McMillan Donald C , St. J. O’Reilly Denis 
Published: September 2005

Abstract
Background: Components of biological variation can be used to define objective quality specifications (imprecision, bias, and total error), to assess the usefulness of reference values [index of individuality (II)], and to evaluate significance of changes in serial results from an individual [reference change value (RCV)]. However, biological variation data on vitamins in blood are limited. The aims of the present study were to determine the intra- and interindividual biological variation of vitamins A, E, B1, B2, B6, C, and K and carotenoids in plasma, whole blood, or erythrocytes from apparently healthy persons and to define quality specifications for vitamin measurements based on their biology.
Methods: Fasting plasma, whole blood, and erythrocytes were collected from 14 healthy volunteers at regular weekly intervals over 22 weeks. Vitamins were measured by HPLC. From the data generated, the intra- (CVI) and interindividual (CVG) biological CVs were estimated for each vitamin. Derived quality specifications, II, and RCV were calculated from CVI and CVG.
Results: CVI was 4.8%–38% and CVG was 10%–65% for the vitamins measured. The CVIs for vitamins A, E, B1, and B2 were lower (4.8%–7.6%) than for the other vitamins in blood. For all vitamins, CVG was higher than CVI, with II &lt;1.0 (range, 0.36–0.95). The RCVs for vitamins were high (15.8%–108%). Apart from vitamins A, B1, and erythrocyte B2, the imprecision of our methods for measurement of vitamins in blood was within the desirable goal.
Conclusions: For most vitamin measurements in plasma, whole blood, or erythrocytes, the desirable imprecision goals based on biological variation are obtainable by current methodologies. Population reference intervals for vitamins are of limited value in demonstrating deficiency or excess.
Improving the levels of essential amino acids and sulfur metabolites in plants
Authors: Galili Gad , Amir Rachel , Hoefgen Rainer , Hesse Holger 
Published: September 2005

AbstractPlants represent the major source of food for humans, either directly or indirectly through their use as livestock feeds. Plant foods are not nutritionally balanced because they contain low proportions of a number of essential metabolites, such as vitamins and amino acids, which humans and a significant proportion of their livestock cannot produce on their own. Among the essential amino acids needed in human diets, Lys, Met, Thr and Trp are considered as the most important because they are present in only low levels in plant foods. In the present review, we discuss approaches to improve the levels of the essential amino acids Lys and Met, as well as of sulfur metabolites, in plants using metabolic engineering approaches. We also focus on specific examples for which a deeper understanding of the regulation of metabolic networks in plants is needed for tailor-made improvements of amino acid metabolism with minimal interference in plant growth and productivity.
Developing an effective RNA interference strategy against a plus-strand RNA virus: silencing of coxsackievirus B3 and its cognate coxsackievirus-adenovirus receptor
Authors: Werk Denise , Schubert Steffen , Lindig Vanessa , Grunert Hans-Peter , Zeichhardt Heinz , Erdmann Volker A. , Kurreck Jens 
Published: September 2005

AbstractCoxsackievirus B3 (CVB-3) is a plus-strand RNA virus that is believed to be the most common causal agent of viral myocarditis. Since no specific treatment for CVB-3 infections is available to date, we and others have recently started to develop RNA interference (RNAi) approaches to prevent virus propagation. Here we describe our strategy for the development of efficient small interfering RNAs (siRNAs) against viral genomes. Initially, fusion constructs of a reporter (green fluorescent protein) and viral subgenomic fragments were employed to select active siRNAs against the virus. Moreover, in an attempt to achieve sustained virus silencing and reduce the risk of generating escape mutants, only highly efficient siRNAs directed against regions of the viral genome that are unlikely to tolerate mutations were considered for virus inhibition. Two siRNAs directed against the 3D RNA-dependent RNA polymerase were found to inhibit virus propagation by 80–90%. The protective effect of the efficient siRNAs lasted for several days. Furthermore, we have first evidence that inhibition of the cellular coxsackievirus-adenovirus receptor (CAR) by RNAi also reduces the virus titre. Our strategy is likely to be applicable to other (RNA) viruses as well.
Regulation of asparagine synthetase gene transcription by the basic region leucine zipper transcription factors ATF5 and CHOP
Authors: Al Sarraj Jude , Vinson Charles , Thiel Gerald 
Published: September 2005

AbstractAsparagine synthetase catalyses the glutamine- and ATP-dependent conversion of aspartic acid to asparagine. In human hepatoma cells cultured in mediumcontaining amino acids, the mRNA of asparagine synthetase is not detectable by RNase protection mapping. However, maintaining the cells in amino acid-free Krebs-Ringer bicarbonate buffer strongly upregulated asparagine synthetase biosynthesis. The effect of amino acid deprivation on asparagine synthetase gene transcription is mediated by a genetic element termed the nutrient-sensing response unit. Previous studies revealed that the basic region leucine zipper (bZIP) transcription factor CREB2/ATF4 is involved in the nutrient deprivation-induced upregulation of asparagine synthetase gene transcription. Here we show that overexpression of the bZIP protein ATF5, a transcriptional activator, stimulates asparagine synthetase promoter/reporter gene transcription via the nutrient-sensing response unit. In contrast, ATF5 does not transactivate cAMP response element (CRE)-containing reporter genes. Overexpression of the C/EBP homologous transcription factor CHOP impaired transcriptional activation of the asparagine synthetase promoter following amino acid deprivation or over-expression of ATF5 or CREB2/ATF4. These data indicate that CHOP functions as a shut-off-device for nutrient deprivation-induced gene transcription.
Cholesterol is the major component of native lipoproteins activating the p38 mitogen-activated protein kinases
Authors: Dobreva Iveta , Zschörnig Olaf , Waeber Gérard , James Richard W. , Widmann Christian 
Published: September 2005

Abstract
Elevated low-density lipoprotein (LDL) levels induce activation of the p38 mitogen-activated protein kinase (MAPK), a stress-activated protein kinase potentially participating in the development of atherosclerosis. The nature of the lipoprotein components inducing p38 MAPK activation has remained unclear however. We show here that both LDLs and high-density lipoproteins (HDLs) have the ability to stimulate the p38 MAPKs with potencies that correlate with their cholesterol content. Cholesterol solubilized in methyl-β-cyclodextrin was sufficient to activate the p38 MAPK pathway. Liposomes made of phosphatidylcholine (PC) or sphingomyelin, the two main phospholipids found in lipoproteins, were unable to stimulate the p38 MAPKs. In contrast, PC liposomes loaded with cholesterol potently activated this pathway. Reducing the cholesterol content of LDL particles lowered their ability to activate the p38 MAPKs. Cell lines representative of the three main cell types found in blood vessels (endothelial cells, smooth muscle cells and fibroblasts) all activated their p38 MAPK pathway in response to LDLs or cholesterol-loaded PC liposomes. These results indicate that elevated cholesterol content in lipoproteins, as seen in hypercholesterolemia, favors the activation of the stress-activated p38 MAPK pathway in cells from the vessel wall, an event that might contribute to the development of atherosclerosis.
Focal adhesion kinase is redistributed to focal complexes and mediates cell spreading in macrophages in response to M-CSF
Authors: Rovida Elisabetta , Lugli Benedetta , Barbetti Valentina , Giuntoli Serena , Olivotto Massimo , Dello Sbarba Persio 
Published: September 2005

AbstractThe macrophage colony-stimulating factor (M-CSF, CSF-1) regulates survival, proliferation and differentiation of mononuclear phagocytes, as well as macrophage motility and morphology. The latter features are usually regulated by ECM-mediated activation of integrins and subsequent tyrosine phosphorylation of cellular proteins, including focal adhesion kinase (FAK). FAK is phosphorylated by downstream receptor tyrosine kinases as well. We addressed the question whether M-CSF regulates FAK tyrosine phosphorylation in macrophages, and found that M-CSF induces FAK phosphorylation at all known tyrosine residues. This phosphorylation was dependent on Src. Extracellularly-regulated kinase (ERK), Jun N-terminal kinase (JNK) and phosphatidylinositol-3-kinase (PI3K) were found to be negatively involved in M-CSF-induced FAK phosphorylation, as their inhibition resulted in FAK hyper-phosphorylation. Following M-CSF treatment, FAK and the active forms of M-CSFR and Src were redistributed to the cytoskeleton, where active ERK, JNK and PI3K were detectable. Immunofluorescence showed the presence of FAK and its active form in focal complexes following M-CSF treatment. Moreover, cell spreading and adhesion were impaired when FAK tyrosine phosphorylation was abrogated by either transfection with FRNK, a dominant negative form of FAK, or treatment with a number of inhibitors of upstream FAK-activating signals. These results point to a relevant role for FAK in the regulation of cell spreading and adhesion in macrophages.
Activation processing of cathepsin H impairs recognition by its propeptide
Authors: Horn Martin , Dolečková-Marešová Lucie , Rulíšek Lubomír , Máša Martin , Vasiljeva Olga , Turk Boris , Gan-Erdene Tudeviin , Baudyš Miroslav , Mareš Michael 
Published: September 2005

AbstractFree propeptides are known to function as inhibitors of the parental mature cysteine cathepsins. This general rule, however, does not apply to the aminopeptidase cathepsin H. Screening of propeptide fragments for their inhibitory potency revealed no significant effect on the native mature cathepsin H. On the other hand, inhibitory interaction was established with recombinant cathepsin H that displays endopeptidase activity due to a lack of the mini-chain. This finding suggests that the propeptide-binding region is structurally rearranged during maturation processing and mini-chain formation, which impairs the effective recognition of mature cathepsin H by its own propeptide.
Reading between the Lines: An Approach to the Musical and Sexual Ambiguities of Death in Venice
Authors: LONGOBARDI RUTH SARA 
Published: September 2005

ABSTRACT
Framing opera as a collaborative genre compels an examination of differences. In particular, opera's media may be understood as simultaneous but not necessarily as cooperative or neutral. This conception of opera raises issues of power dynamics and the politics of voice, both within the work and among its artists. In Benjamin Britten's Death in Venice, musico-dramatic dissonances center on the protagonist's homoerotic obsession with a young boy. His momentous “I love you” at the end of the act 1 finale is accompanied by a musical gesture that does not affirm but rather resists this coming-out event. The gesture's subsequent transformations in other passages that contain no text, and two years later in Britten's Third String Quartet, reinforce the sense of musical opposition to the libretto's homosexual trajectory—a trajectory that results in the protagonist's shame and untimely death.
If musical detachment from the libretto suggests subtext, then it also points to alternative voices. Britten's homosexuality, and the pressures that accumulated around sexual identity in postwar England, argue for connections between musical distance and closeted discourse. Analysis must acknowledge the role of the composer's experiences in the varying characterizations of the protagonist but must also cope with the limits to this type of investigation: The attempt to draw definitive connections between music and sexuality limits the suppleness of our critical apparatus. Conceiving of opera as collaboration prompts a reevaluation of the work as potentially contradictory and fragmented but also advocates against the resolution of such contradictions into coherent authorial statements. Collaboration dislodges autonomy and unity and in their place recommends polyphonies—of authors and voices, among media but also within them.
The Pedagogy of Polyphony in Gabriel Sagard's Histoire du Canada
Authors: BLOECHL OLIVIA A. 
Published: September 2005

ABSTRACT
The second edition of Gabriel Sagard's history of the Recollect missions in eastern Canada, the Histoire du Canada (1636), included an unprecedented series of harmonized settings of four previously transcribed indigenous Mi'kmaq and Tupinamba melodies. A reading of the Histoire du Canada's content, structure, and production context demonstrates that the settings supported the apostolic aims of the text, which were rooted in the didactic ethos and methods of the French Counter-Reformation. Specifically, the Histoire du Canada developed the transcribed indigenous chants into devotional exercises by ascribing moral significance to the transformation of the melodies into polyphony. With the harmonized settings Sagard gestured toward the Native Americans' potential for conversion and civilization by the Recollect missionaries in a manner that was edifying for Catholic readers in France and the young colony.
Finishing Josquin's “Unfinished” Mass: A Case of Stylistic Imitation in the Cappella Sistina
Authors: RODIN JESSE 
Published: September 2005

ABSTRACT
In all but one source for Josquin's Missa L'homme armé super voces musicales the Credo mysteriously lacks the text “Et in spiritum … ecclesiam.” A setting of the missing text is found only in a Vatican manuscript (VatS 154) compiled ca. 1550–55 by Johannes Parvus, where it appears in situ as a discrete mass section that incorporates a complete statement of the cantus firmus. Though preserved in a late source, the Et in spiritum is remarkably close in musical style to the remainder of Josquin's mass.
An analysis of the Et in spiritum with respect to the rest of the mass indicates that it is probably not by Josquin. Given the close stylistic connections between the two pieces, however, this finding suggests that the Et in spiritum was a papal singer's self-conscious imitation of a mass composed some 60 years earlier. The new mass section is distinctly unlike most 16th-century “uses” of Josquin, which tend to adapt his music to a thoroughly contemporary aesthetic. By contrast, this “completion” of Josquin's mass, informed by a culture of traditionalism in the papal chapel, alerts us to a rare but significant kind of musical borrowing in mid-16th-century Rome.
Photophysical, Photochemical, and Tumor‐selectivity Properties of Bromine Derivatives of Rhodamine‐123
Authors: Lacerda Silvia H. D. , Abraham Bindu , Stringfellow Thomas C. , Indig Guilherme L. 
Published: September 2005

ABSTRACTThe conceptual basis for the development of mitochondrial targeting as a novel therapeutic strategy for both chemotherapy and photochemotherapy of neoplastic diseases rests on the observation that enhanced mitochondrial membrane potential is a common tumor cell phenotype. The potential of this strategy is highlighted by the fact that the toxic effects associated with a number of cationic dyes known to localize in energized cell mitochondria are much more pronounced in tumor cells than in normal cells. Here we evaluate the phototoxic properties of four bromine derivatives of rhodamine‐123 toward human uterine sarcoma (MES‐SA) and green monkey kidney (CV‐1) cells and compare the degrees of tumor cell selectivity associated with these dyes with those associated with two model mitochondrial triarylmethanes (crystal violet and ethyl violet). Selective phototoxicity toward tumor cells was found to be highly dependent upon the lipophilic/hydrophilic character of the cationic photosensitizer. Our experimental data have indicated that the probability of success of mitochondrial targeting in (photo)chemotherapy of neoplastic diseases is higher when the octan‐1‐ol/water partition coefficient of the drug candidate falls within approximately two orders of magnitude from that of the prototypical mitochondria‐specific dye rhodamine‐123.
Epidermal Growth Factor as a Candidate for Ex Vivo Expansion of Bone Marrow–Derived Mesenchymal Stem Cells
Authors: Tamama Kenichi , Fan Vivian H. , Griffith Linda G. , Blair Harry C. , Wells Alan 
Published: September 2005

Abstract
Bone marrow mesenchymal stem cells (BMMSCs) are pluripotent cells capable of differentiating into several cell types and are thus an attractive cell source for connective tissue engineering. A challenge in such a use is expansion and directed seeding in vitro, requiring proliferation and survival, and directed migration, respectively, prior to functional differentiation. The epidermal growth factor (EGF) receptor (EGFR) is the prototypal growth factor receptor and elicits these responses from a wide variety of stromal, epithelial, and endothelial cells. Ligands for this receptor are appealing for use in tissue engineering because they are relatively resistant to biological extremes and amenable to high-volume production. Therefore, we determined whether an EGFR ligand, EGF, could be used for ex vivo expansion of BMMSCs. EGF stimulated motility in rat and immortalized human BMMSCs. EGF-induced proliferation was observed in immortalized human BMMSCs but was not apparent in rat BMMSCs under our experimental conditions. EGF did not, however, rescue either type of BMMSC from apoptosis due to lack of serum. During our examination of key signaling intermediaries, EGF caused robust phosphorylation of extracellular signal-regulated protein kinase (ERK) and protein kinase B/akt (AKT) but only minimal phosphorylation of EGFR and phospholipase C-γ in rat BMMSCs, whereas in the human BMMSCs these intermediaries were all strongly activated. EGF also induced robust ERK activation in primary porcine mesenchymal stem cells. EGF pretreatment or cotreatment did not interfere with secondarily induced differentiation of either type of BMMSC into adipogenic or osteogenic lineages. Platelet-derived growth factor (PDGF) effects were similar to but not additive with those elicited by EGF, with some quantitative differences; however, PDGF did interfere with the differentiation of these BMMSCs. These findings suggest that EGFR ligands could be used for ex vivo expansion and direction of BMMSCs.
Methods for Speciation of Metals in Soils
Authors: D'Amore J. J. , Al‐Abed S. R. , Scheckel K. G. , Ryan J. A. 
Published: September 2005

ABSTRACTThe inability to determine metal species in soils hampers efforts to understand the mobility, bioavailability, and fate of contaminant metals in environmental systems, to assess health risks posed by them, and to develop methods to remediate metal contaminated sites. Fortunately, great strides have been made in the development of methods of species characterization and in their application to the analysis of particulates and mixtures of solid phases in physics, analytical chemistry, and materials science. This manuscript highlights a selection of the analytical methods available today offering the greatest promise, briefly describes the fundamental processes involved, examines their limitations, points to how they have been used in the environmental and geochemical literature, and offers some suggested research directions in the hope of stimulating further investigation into the application of these powerful tools to the problems outlined above.