bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors regulating tachyphylaxis triggered by N-terminal-modified angiotensin II analogs
Authors: Barros Alexandre J. , Ito Christian M. , Makino Elaine N. , Cembranelli Fernando A.M. , Moraes Francisco C. , Souza Sinval E.G. , Oliveira Laerte , Shimuta Suma I. , Nakaie Clovis R. 
Published: October 2009

AbstractBinding of angiotensin II (DRVYIHPF, AngII) to its AT1receptor can trigger a process known as tachyphylaxis (loss of receptor response owing to repeated agonist stimulation). We propose a two-state binding model for tachyphylaxis where the N-terminal Asp1and Arg2residues of the peptide are supposed to initially bind to the N-terminal segment (Arg23) and to the EC-3 loop (Asp281) of an AT1molecule, respectively (state 1). Sequentially, a disruption of the salt bond between the AngII Asp1β-carboxyl function and the receptor Arg23can occur with release of the peptide N-terminal segment, favoring the binding of the Arg2residue to the EC-3 loop (Asp178,281, state 2). In the present study, we expanded this investigation by assaying pharmacological properties of different AngII analogs in guinea-pig ileum bearing modifications at positions 1 and 2. Most of these peptides were weak agonists but many of them had the ability to induce tachyphylaxis. These findings support the two-state model for tachyphylaxis, but alternative mechanisms were revealed where state 1 was no longer needed, depending on the chemical structure of AngII residue 1. Otherwise, any modification of the wild type AngII Arg2residue was deleterious for the tachyphylaxis mechanism.
Chemokines in tumor-associated angiogenesis
Authors: Gerber Peter Arne , Hippe Andreas , Buhren Bettina Alexandra , Müller Anja , Homey Bernhard 
Published: October 2009

AbstractTumor growth is dependent on several key factors. Apart from immune escape and an efficient blockade of apoptotic signals, tumors require oxygen and nutrients to grow past a diameter of 2 μm. Therefore, it is of vital importance for the tumor to facilitate tumor-associated angiogenesis, e.g., thede novoformation of new blood vessels. In addition to established and key angiogenic factors, such as vascular endothelial growth factor, chemokines, a superfamily of cytokine-like proteins that bind to seven transmembrane-spanning G-protein-coupled receptors, have been associated with angiogenesis under homeostatic conditions. Chemokines were initially identified as key factors that control the directional migration of leukocytes, stem cells and cancer cellsin vitroand which critically regulate their traffickingin vivo. Recently their role in establishing a favorable microenvironment for tumor-associated angiogenesis, a process that requires complex bidirectional interactions of the tumor and associated vessels, has been the focus of research. Chemokine-promoted angiogenesis not only facilitates tumor growth by supplying nutrients and oxygen but it is also a prerequisite to tumor metastasis. Hence, the pharmacologic control of tumor angiogenesis presents a promising strategy for novel anticancer therapeutics. Here, we discuss the current pathogenetic concepts of tumor-associated angiogenesis in the context of chemokines and their receptors and highlight promising therapeutic strategies.
Hexose-6-phosphate dehydrogenase in the endoplasmic reticulum
Authors: Senesi Silvia , Csala Miklos , Marcolongo Paola , Fulceri Rosella , Mandl Jozsef , Banhegyi Gabor , Benedetti Angelo 
Published: October 2009

AbstractHexose-6-phosphate dehydrogenase (H6PD) is a luminal enzyme of the endoplasmic reticulum that is distinguished from cytosolic glucose-6-phosphate dehydrogenase by several features. H6PD converts glucose-6-phosphate and NADP+to 6-phosphogluconate and NADPH, thereby catalyzing the first two reactions of the pentose-phosphate pathway. Because the endoplasmic reticulum has a separate pyridine nucleotide pool, H6PD provides NADPH for luminal reductases. One of these enzymes, 11β-hydroxysteroid dehydrogenase type 1 responsible for prereceptorial activation of glucocorticoids, has been the focus of much attention as a probable factor in the pathomechanism of several human diseases including insulin resistance and the metabolic syndrome. This review summarizes recent advances related to the functions of H6PD.
Crystal structure of 4-hydroxybutyrate CoA-transferase from Clostridium aminobutyricum
Authors: Macieira Sofia , Zhang Jin , Velarde Milko , Buckel Wolfgang , Messerschmidt Albrecht 
Published: October 2009

Abstract
4-Hydroxybutyrate CoA-transferases (4-HB-CoAT) takes part in the fermentation of 4-aminobutyrate to ammonia, acetate, and butyrate in anaerobic bacteria such as Clostridium aminobutyricum and Porphyromonas gingivalis or facultative anaerobic bacteria such as Shewanella oneidensis. Site-directed mutagenesis of the highly active enzyme has identified the catalytic glutamate residue as E238. Crystal structure of this enzyme has been determined at a resolution of 1.85 Å. The 438-amino acid residue polypeptide chain folds into two topologically similar domains with an open α/β-fold, which is also found in other CoAT family I and family II members. The data indicate that the members of CoAT families I and II are closely related; the latter only lacking the catalytic glutamate residue. A putative co-substrate binding site for the 4-HB-CoAT was identified, in which a 4-hydroxybutyrate molecule has been modeled. This site is also responsible for binding the acetyl group of acetyl-CoA or the succinyl group of succinyl-CoA in succinyl-CoA:3-oxoacid CoA-transferase from mammalian mitochondria. Mutations of relevant active site amino acid residues have been produced and their activities tested to corroborate the proposed structural model for substrate binding. 4-HB-CoAT from C. aminobutyricum represents the only functionally characterized 4-HB-CoAT present in the structural database.
Zustandsregelung linearer Systeme — Eine NeubetrachtungState Feedback Control of Linear Systems — a Renewed Approach
Authors: Roppenecker Günter 
Published: October 2009

Zusammenfassung
Die bislang übliche Struktur zur Zustandsregelung linearer Systeme besteht aus einer Zustandsrückführung und einer Führungsgrößenaufschaltung über ein konstantes Vorfilter. Im Unterschied zur bewährten klassischen Regelung enthält sie keinen Soll-Istwert-Vergleich und die Aufschaltung über das Vorfilter ist abhängig vom Zustandsregler. Dieser Beitrag zeigt, dass Zustandsregelungen auch in eine Struktur mit Soll-Istwert-Vergleich überführt werden können, die zudem eine vom Zustandsregler unabhängige Vorsteuerung zur Führungs- und gegebenenfalls auch Störgrößenaufschaltung ermöglicht. Letztendlich können somit Zustandsregelungen immer auch in Form einer gewöhnlichen Regelung mit Soll-Istwert-Vergleich für die Regelgröße realisiert werden. Bei Verwendung einer modellgestützten Vorsteuerung lassen sich dabei das Führungsverhalten, die Reaktion auf durch Messung bekannte Störgrößen und die Ausregelung der sonstigen Einflüsse jeweils getrennt voneinander einstellen.
Selbstkalibrierung von Rasterkraftmikroskopen — Abbildung der PositionsabweichungenSelf Calibration of SPM — Mapping the Errors of the Instrument
Authors: Xu Min , Dziomba Thorsten , Dai Gaoliang , Koenders Ludger 
Published: October 2009

Zusammenfassung
Ein Selbstkalibrierungsverfahren zur Abbildung der Positionsabweichungen in der x-y-Ebene und der Rechtwinkligkeitsabweichungen zwischen der z-Achse und der x-y-Ebene von Rasterkraftmikroskopen (engl. Scanning Force Microscopes, SFM) wurde entwickelt und angewendet. Das Verfahren zur Selbstkalibrierung hat Vorteile: einfacher Aufbau, und mit seiner Hilfe können sowohl Unregelmäßigkeiten von Maßverkörperungen als auch Abweichungen vom Idealverhalten von SFMs bestimmt und voneinander getrennt werden. Grenzen sind nur durch die Stabilität des Gerätes und der benutzten Probe gegeben. Zwei handelsübliche SFMs wurden unter Anwendung der vorgeschlagenen Methode untersucht. Die Ergebnisse eines dieser Geräte werden hier zur Illustration der Anwendung gezeigt. Die erzielten Ergebnisse stimmen gut mit denen überein, die klassische Kalibriermethoden mit hochgenauen Transfernormalen und messtechnischen Geräten lieferten. Das Selbstkalibrierungsverfahren bietet sich damit als eine wirkungsvolle Methode zur Abbildung weiterer Fehler von Rasterkraftmikroskopen an.
Einflüsse von Beschleunigungskräften auf einen DrucksensorAcceleration-Induced Effects on a Pressure Sensor
Authors: Gradolph Christian , Friedberger Alois , Müller Gerhard , Wilde Jürgen 
Published: October 2009

Zusammenfassung
Drucksensoren für aerodynamische Messungen in Hubschrauber-Rotorblättern müssen hohe Anforderungen an die Druckauflösung erfüllen. Gleichzeitig aber unterliegen sie sehr rauen Umgebungsbedingungen wie den dort herrschenden enormen Fliehkräften und Vibrationen. Die Einflüsse dieser Belastungen auf das Verhalten der Sensorkomponenten und die Querempfindlichkeit des Drucksensors werden analysiert.
Efficient Transposition of Tol2 in the Mouse Germline
Authors: Keng Vincent W , Ryan Barbara J , Wangensteen Kirk J , Balciunas Darius , Schmedt Christian , Ekker Stephen C , Largaespada David A 
Published: October 2009

Abstract
Insertional mutagenesis screens play an integral part in the annotating of functional data for all sequenced genes in the postgenomic era. Chemical mutagenesis screens are highly efficient but identifying the causative gene can be a laborious task. Other mutagenesis platforms, such as transposable elements, have been successfully applied for insertional mutagenesis screens in both the mouse and rat. However, relatively low transposition efficiency has hampered their use as a high-throughput forward genetic mutagenesis screen. Here we report the first evidence of germline activity in the mouse using a naturally active DNA transposon derived from the medaka fish called Tol2, as an alternative system for high-throughput forward genetic mutagenesis screening tool.
The Genetic Basis of Phenotypic Adaptation II: The Distribution of Adaptive Substitutions in the Moving Optimum Model
Authors: Kopp Michael , Hermisson Joachim 
Published: October 2009

AbstractWe consider a population that adapts to a gradually changing environment. Our aim is to describe how ecological and genetic factors combine to determine the genetic basis of adaptation. Specifically, we consider the evolution of a polygenic trait that is under stabilizing selection with a moving optimum. The ecological dynamics are defined by the strength of selection, $\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{{\tilde{{\sigma}}}}\) \end{document}$, and the speed of the optimum, $\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \({\tilde{v}}\) \end{document}$; the key genetic parameters are the mutation rate Θ and the variance of the effects of new mutations, ω. We develop analytical approximations within an “adaptive-walk” framework and describe how selection acts as a sieve that transforms a given distribution of new mutations into the distribution of adaptive substitutions. Our analytical results are complemented by individual-based simulations. We find that (i) the ecological dynamics have a strong effect on the distribution of adaptive substitutions and their impact depends largely on a single composite measure $\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{{\gamma}}{=}{\tilde{v}}/(\mathrm{{\tilde{{\sigma}}}}{\Theta}\mathrm{{\omega}}^{3})\) \end{document}$, which combines the ecological and genetic parameters; (ii) depending on γ, we can distinguish two distinct adaptive regimes: for large γ the adaptive process is mutation limited and dominated by genetic constraints, whereas for small γ it is environmentally limited and dominated by the external ecological dynamics; (iii) deviations from the adaptive-walk approximation occur for large mutation rates, when different mutant alleles interact via linkage or epistasis; and (iv) in contrast to predictions from previous models assuming constant selection, the distribution of adaptive substitutions is generally not exponential.
Centromere Replication Timing Determines Different Forms of Genomic Instability inSaccharomyces cerevisiaeCheckpoint Mutants During Replication Stress
Authors: Feng Wenyi , Bachant Jeff , Collingwood David , Raghuraman M K , Brewer Bonita J 
Published: October 2009

AbstractYeast replication checkpoint mutants lose viability following transient exposure to hydroxyurea, a replication-impeding drug. In an effort to understand the basis for this lethality, we discovered that different events are responsible for inviability in checkpoint-deficient cells harboring mutations in the mec1 and rad53 genes. By monitoring genomewide replication dynamics of cells exposed to hydroxyurea, we show that cells with a checkpoint deficient allele of RAD53, rad53K227A, fail to duplicate centromeres. Following removal of the drug, however, rad53K227A cells recover substantial DNA replication, including replication through centromeres. Despite this recovery, the rad53K227A mutant fails to achieve biorientation of sister centromeres during recovery from hydroxyurea, leading to secondary activation of the spindle assembly checkpoint (SAC), aneuploidy, and lethal chromosome segregation errors. We demonstrate that cell lethality from this segregation defect could be partially remedied by reinforcing bipolar attachment. In contrast, cells with the mec1-1 sml1-1 mutations suffer from severely impaired replication resumption upon removal of hydroxyurea. mec1-1 sml1-1 cells can, however, duplicate at least some of their centromeres and achieve bipolar attachment, leading to abortive segregation and fragmentation of incompletely replicated chromosomes. Our results highlight the importance of replicating yeast centromeres early and reveal different mechanisms of cell death due to differences in replication fork progression.
Deleting the 14-3-3 Protein Bmh1 Extends Life Span inSaccharomyces cerevisiaeby Increasing Stress Response
Authors: Wang Chen , Skinner Craig , Easlon Erin , Lin Su-Ju 
Published: October 2009

AbstractEnhanced stress response has been suggested to promote longevity in many species. Calorie restriction (CR) and conserved nutrient-sensing target of rapamycin (TOR) and protein kinase A (PKA) pathways have also been suggested to extend life span by increasing stress response, which protects cells from age-dependent accumulation of oxidative damages. Here we show that deleting the yeast 14-3-3 protein, Bmh1, extends chronological life span (CLS) by activating the stress response. 14-3-3 proteins are highly conserved chaperone-like proteins that play important roles in many cellular processes. bmh1Δ-induced heat resistance and CLS extension require the general stress-response transcription factors Msn2, Msn4, and Rim15. The bmh1Δ mutant also displays a decreased reactive oxygen species level and increased heat-shock-element-driven transcription activity. We also show that BMH1 genetically interacts with CR and conserved nutrient-sensing TOR- and PKA-signaling pathways to regulate life span. Interestingly, the level of phosphorylated Ser238 on Bmh1 increases during chronological aging, which is delayed by CR or by reduced TOR activities. In addition, we demonstrate that PKA can directly phosphorylate Ser238 on Bmh1. The status of Bmh1 phosphorylation is therefore likely to play important roles in life-span regulation. Together, our studies suggest that phosphorylated Bmh1 may cause inhibitory effects on downstream longevity factors, including stress-response proteins. Deleting Bmh1 may eliminate the inhibitory effects of Bmh1 on these longevity factors and therefore extends life span.
A Genomewide RNAi Screen for Genes That Affect the Stability, Distribution and Function of P Granules in Caenorhabditis elegans
Authors: Updike Dustin L , Strome Susan 
Published: October 2009

Abstract
P granules are non-membrane-bound organelles found in the germ-line cytoplasm throughout Caenorhabditis elegans development. Like their “germ granule” counterparts in other animals, P granules are thought to act as determinants of the identity and special properties of germ cells, properties that include the unique ability to give rise to all tissues of future generations of an organism. Therefore, understanding how P granules work is critical to understanding how cellular immortality and totipotency are retained, gained, and lost. Here we report on a genomewide RNAi screen in C. elegans, which identified 173 genes that affect the stability, localization, and function of P granules. Many of these genes fall into specific classes with shared P-granule phenotypes, allowing us to better understand how cellular processes such as protein degradation, translation, splicing, nuclear transport, and mRNA homeostasis converge on P-granule assembly and function. One of the more striking phenotypes is caused by the depletion of CSR-1, an Argonaute associated with an endogenous siRNA pathway that functions in the germ line. We show that CSR-1 and two other endo-siRNA pathway members, the RNA-dependent RNA polymerase EGO-1 and the helicase DRH-3, act to antagonize RNA and P-granule accumulation in the germ line. Our findings strengthen the emerging view that germ granules are involved in numerous aspects of RNA metabolism, including an endo-siRNA pathway in germ cells.
Prevalence of Parent-Reported Diagnosis of Autism Spectrum Disorder Among Children in the US, 2007
Authors: Kogan Michael D. , Blumberg Stephen J. , Schieve Laura A. , Boyle Coleen A. , Perrin James M. , Ghandour Reem M. , Singh Gopal K. , Strickland Bonnie B. , Trevathan Edwin , van Dyck Peter C. 
Published: October 2009

OBJECTIVES: The reported increasing prevalence of autism spectrum disorder (ASD) and attendant health and family impact make monitoring of ASD prevalence a public health priority.
METHODS: The prevalence of parent-reported diagnosis of ASD among US children aged 3 to 17 years was estimated from the 2007 National Survey of Children's Health (sample size: 78037). A child was considered to have ASD if a parent/guardian reported that a doctor or other health care provider had ever said that the child had ASD and that the child currently had the condition. The point-prevalence for ASD was calculated for those children meeting both criteria. We examined sociodemographic factors associated with current ASD and with a past (but not current) ASD diagnosis. The health care experiences for children in both ASD groups were explored.
RESULTS: The weighted current ASD point-prevalence was 110 per 10,000. We estimate that 673,000 US children have ASD. Odds of having ASD were 4 times as large for boys than girls. Non-Hispanic (NH) black and multiracial children had lower odds of ASD than NH white children. Nearly 40% of those ever diagnosed with ASD did not currently have the condition; NH black children were more likely than NH white children to not have current ASD. Children in both ASD groups were less likely than children without ASD to receive care within a medical home.
CONCLUSIONS: The observed point-prevalence is higher than previous US estimates. More inclusive survey questions, increased population awareness, and improved screening and identification by providers may partly explain this finding.
Life History, Ecology, and Long-term Demographics of Queenfish
Authors: Miller Eric F. , Williams Jonathan P. , Pondella Daniel J. , Herbinson Kevin T. 
Published: October 2009

Abstract
Queenfish Seriphus politus were collected at coastal power plants from San Clemente to Ventura, California. Power functions best described relations between otolith length, width, or weight and either standard length (SL) or total body weight. The length–weight relationship was described by the following equation: weight = 10−5 × SL3.09. Individuals were aged to 12 years by using sagittal otolith sections. Females grew at a significantly faster rate than males. Both sexes reached 50% maturity by 100 mm SL, or shortly after age 1. The total annual instantaneous mortality coefficient was estimated at 0.42. Catalina Harbor (on the windward side of Santa Catalina Island) and Ventura were the most populous sites based on gill-net catch per unit effort from 1995 to 2006. Juvenile and adult queenfish populations have declined since 1980 in a significant relationship with nearshore plankton biomass. Larval queenfish densities recorded in King Harbor (Redondo Beach) have declined since 1987. Long-term recruitment estimates indicated peak recruitment prior to 1976, with three subsequent downward baseline shifts.
Use of a Fishery-Independent Trawl Survey to Evaluate Distribution Patterns of Subadult Sharks in Georgia
Authors: Belcher Carolyn N. , Jennings Cecil A. 
Published: October 2009

Abstract
We investigated the utility of a fishery-independent trawl survey for assessing a potential multispecies shark nursery in Georgia's nearshore and inshore waters. A total of 234 subadult sharks from six species were captured during 85 of 216 trawls. Catch rates and size distributions for subadult sharks and the ratio of neonates to juveniles were consistent among areas. The highest concentrations of subadult sharks occurred in creeks and sounds. Species composition varied among areas. The Atlantic sharpnose shark Rhizoprionodon terraenovae was the most abundant species in sound and nearshore stations, whereas the bonnethead Sphyrna tiburo was the most abundant species in creeks. The aggregate of other species occurred with higher frequency in the sounds and nearshore. Sampling characteristics of the trawl survey were compared with those from a fishery-independent longline survey of subadult sharks to assess the similarity of the two gears. A total of 193 subadult sharks from seven species were captured during 57 of 96 longline sets, whereas 52 subadults from four species were captured during 20 of 48 trawls. Selectivity and efficiency differed between the two gears. The trawl had lower catch rates, caught smaller sharks, and encountered a different suite of species than the longline. General seasonal trends in relative abundance also differed between the two gears; the longline showed an increasing trend in abundance, whereas the trawl showed a stable trend. Although trawls were not found to be efficient for sampling subadult sharks from most species, they can be a useful source of supplemental data.