bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of Chromosomal Boundary Action: Roadblock, Sink, or Loop?
Authors: Gohl Daryl , Aoki Tsutomu , Blanton Jason , Shanower Greg , Kappes Gretchen , Schedl Paul 
Published: January 2011

AbstractBoundary elements or insulators subdivide eukaryotic chromosomes into a series of structurally and functionally autonomous domains. They ensure that the action of enhancers and silencers is restricted to the domain in which these regulatory elements reside. Three models, the roadblock, sink/decoy, and topological loop, have been proposed to explain the insulating activity of boundary elements. Strong predictions about how boundaries will function in different experimental contexts can be drawn from these models. In the studies reported here, we have designed assays that test these predictions. The results of our assays are inconsistent with the expectations of the roadblock and sink models. Instead, they support the topological loop model.
Analysis of B-Genome Chromosome Introgression in Interspecific Hybrids of Brassica napus × B. carinata
Authors: Navabi Zahra K , Stead Kiersten E , Pires J Chris , Xiong Zhiyong , Sharpe Andrew G , Parkin Isobel A P , Rahman M Habibur , Good Allen G 
Published: January 2011

Abstract
Brassica carinata, an allotetraploid with B and C genomes, has a number of traits that would be valuable to introgress into B. napus. Interspecific hybrids were created between B. carinata (BBCC) and B. napus (AACC), using an advanced backcross approach to identify and introgress traits of agronomic interest from the B. carinata genome and to study the genetic changes that occur during the introgression process. We mapped the B and C genomes of B. carinata with SSR markers and observed their introgression into B. napus through a number of backcross generations, focusing on a BC3 and BC3S1 sibling family. There was close colinearity between the C genomes of B. carinata and B. napus and we provide evidence that B. carinata C chromosomes pair and recombine normally with those of B. napus, suggesting that similar to other Brassica allotetraploids no major chromosomal rearrangements have taken place since the formation of B. carinata. There was no evidence of introgression of the B chromosomes into the A or C chromosomes of B. napus; instead they were inherited as whole linkage groups with the occasional loss of terminal segments and several of the B-genome chromosomes were retained across generations. Several BC3S1 families were analyzed using SSR markers, genomic in situ hybridization (GISH) assays, and chromosome counts to study the inheritance of the B-genome chromosome(s) and their association with morphological traits. Our work provides an analysis of the behavior of chromosomes in an interspecific cross and reinforces the challenges of introgressing novel traits into crop plants.
Molecular Evolution, Mutation Size and Gene Pleiotropy: A Geometric Reexamination
Authors: Razeto-Barry Pablo , Díaz Javier , Cotoras Darko , Vásquez Rodrigo A 
Published: January 2011

Abstract
The influence of phenotypic effects of genetic mutations on molecular evolution is not well understood. Neutral and nearly neutral theories of molecular evolution predict a negative relationship between the evolutionary rate of proteins and their functional importance; nevertheless empirical studies seeking relationships between evolutionary rate and the phenotypic role of proteins have not produced conclusive results. In particular, previous studies have not found the expected negative correlation between evolutionary rate and gene pleiotropy. Here, we studied the effect of gene pleiotropy and the phenotypic size of mutations on the evolutionary rate of genes in a geometrical model, in which gene pleiotropy was characterized by n molecular phenotypes that affect organismal fitness. For a nearly neutral process, we found a negative relationship between evolutionary rate and mutation size but pleiotropy did not affect the evolutionary rate. Further, for a selection model, where most of the substitutions were fixed by natural selection in a randomly fluctuating environment, we also found a negative relationship between evolutionary rate and mutation size, but interestingly, gene pleiotropy increased the evolutionary rate as $\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\sqrt{n}\) \end{document}$. These findings may explain part of the disagreement between empirical data and traditional expectations.
New Insight Into the Role of the Cdc34 Ubiquitin-Conjugating Enzyme in Cell Cycle Regulation via Ace2 and Sic1
Authors: Cocklin Ross , Heyen Joshua , Larry Tolonda , Tyers Mike , Goebl Mark 
Published: January 2011

Abstract
The Cdc34 ubiquitin-conjugating enzyme plays a central role in progression of the cell cycle. Through analysis of the phenotype of a mutant missing a highly conserved sequence motif within the catalytic domain of Cdc34, we discovered previously unrecognized levels of regulation of the Ace2 transcription factor and the cyclin-dependent protein kinase inhibitor Sic1. In cells carrying the Cdc34tm mutation, which alters the conserved sequence, the cyclin-dependent protein kinase inhibitor Sic1, an SCFCdc4 substrate, has a shorter half-life, while the cyclin Cln1, an SCFGrr1 substrate, has a longer half-life than in wild-type cells. Expression of the SIC1 gene cluster, which is regulated by Swi5 and Ace2 transcription factors, is induced in CDC34tm cells. Levels of Swi5, Ace2, and the SCFGrr1 targets Cln1 and Cln2 are elevated in Cdc34tm cells, and loss of Grr1 causes an increase in Ace2 levels. Sic1 levels are similar in CDC34tm ace2Δ and wild-type cells, explaining a paradoxical increase in the steady-state level of Sic1 protein despite its reduced half-life. A screen for mutations that interact with CDC34tm uncovered novel regulators of Sic1, including genes encoding the polyubiquitin chain receptors Rad23 and Rpn10.
A Genome-Wide Enhancer Screen Implicates Sphingolipid Composition in Vacuolar ATPase Function in Saccharomyces cerevisiae
Authors: Finnigan Gregory C , Ryan Margret , Stevens Tom H 
Published: January 2011

Abstract
The function of the vacuolar H+-ATPase (V-ATPase) enzyme complex is to acidify organelles; this process is critical for a variety of cellular processes and has implications in human disease. There are five accessory proteins that assist in assembly of the membrane portion of the complex, the V0 domain. To identify additional elements that affect V-ATPase assembly, trafficking, or enzyme activity, we performed a genome-wide enhancer screen in the budding yeast Saccharomyces cerevisiae with two mutant assembly factor alleles, VMA21 with a dysfunctional ER retrieval motif (vma21QQ) and vma21QQ in combination with voa1Δ, a nonessential assembly factor. These alleles serve as sensitized genetic backgrounds that have reduced V-ATPase enzyme activity. Genes were identified from a variety of cellular pathways including a large number of trafficking-related components; we characterized two redundant gene pairs, HPH1/HPH2 and ORM1/ORM2. Both sets demonstrated synthetic growth defects in combination with the vma21QQ allele. A loss of either the HPH or ORM gene pairs alone did not result in a decrease in vacuolar acidification or defects in V-ATPase assembly. While the Hph proteins are not required for V-ATPase function, Orm1p and Orm2p are required for full V-ATPase enzyme function. Consistent with the documented role of the Orm proteins in sphingolipid regulation, we have found that inhibition of sphingolipid synthesis alleviates Orm-related growth defects.
Fiscal Federalism at the Ballot Box: The Relevance of Expressive Voting
Authors: Jones Philip , Soguel Nils 
Published: January 2011

Abstract
This paper explores the impact of citizens’ motivation to vote on the pattern of fiscal federalism. If the only concern of instrumental citizens was outcome they would have little incentive to vote because the probability that a single vote might change an electoral outcome is usually minuscule. If voters turn out in large numbers to derive intrinsic value from action, how will these voters choose when considering the role local jurisdictions should play? The first section of the paper assesses the weight that expressive voters attach to an instrumental evaluation of alternative outcomes. Predictions are tested with reference to case study analysis of the way Swiss voters assessed the role their local jurisdiction should play. The relevance of this analysis is also assessed with reference to the choice that voters express when considering other local issues. Textbook analysis of fiscal federalism is premised on the assumption that voters register choice just as ‘consumers’ reveal demand for services in a market, but how robust is this analogy?
How Federalism Protects Future Generations from Today's Public Debts
Authors: Eichenberger Reiner , Stadelmann David 
Published: January 2011

Abstract
From the politico-economic perspective, federalism is a protector of the present generation. But what about future generations? In federal states, Ricardian equivalence cannot be assumed to work properly, as migration between local jurisdictions undermines intergenerational redistribution based on parental altruism. However, we argue that there exists another equivalence mechanism which also works with purely selfish individuals: Public debts capitalize into property values. Jurisdictions with larger net debts exhibit, ceteris paribus, lower property prices. Debt capitalization in property values is the more pronounced the less elastic land supply is and the more mobile the other factors of production are. Therefore, capitalization is more relevant for local than for national debts, i.e. it is more pronounced in a federal than in a centralized state. Thus, federalism also becomes a protector of future generations.
The Influence of Public Institutions on the Shadow Economy: An Empirical Investigation for OECD Countries
Authors: Schneider Friedrich 
Published: January 2011

Abstract
The size and development of the shadow economy of 21 OECD countries is estimated, using the MIMIC estimation procedure. The analysis finds that an increased burden of taxation and social security payments, combined with intensive labor market regulation, quality of state institutions, and tax morale, are the driving forces for the shadow economy. The public institution of federalism has no statistically significant effect on the shadow economy. Finally, on the one side, incentive-oriented policy means are suggested so that any “black” value added can be transformed into official value added, and on the other side, it is important to have public institutions which work efficiently and act as a constraint for selfish politicians.
Fiscal Equity In Federal Systems
Authors: Brennan Geoffrey , Pincus Jonathan J. 
Published: January 2011

Abstract
This paper examines the normative foundations of fiscal equalization – an issue handled, apparently decisively, in a classic paper by James Buchanan (1950). Contrary to Buchanan's claims, we argue that fiscal equalization requires extremely strong value judgements – at least in the case where fiscal differences arise from the interaction of public goods provision under different population size – effectively committing one to a Rawlsian maximin rule. Much weaker forms of the 'social welfare function' in this public goods case will generate the requirement that private consumption levels be equalized, but specifically not public consumption levels – in which sense private goods equalization seems normatively weaker than public goods equalization, If this is so, the hope of justifying federal fiscal equalization on the basis of relatively uncontroversial individualistic norms seems illusory.
Evaluation of minimally invasive excisional brain biopsy and intracranial brachytherapy catheter placement in dogs
Authors: Packer Rebecca A. , Freeman Lynetta J. , Miller Margaret A. , Fauber Amy E. , Morrison Wallace B. 
Published: January 2011

Abstract
Objective—To evaluate a technique for minimally invasive excisional brain biopsy and intracranial brachytherapy catheter placement in dogs.
Animals—5 healthy adult female dogs.
Procedures—Computed tomographic guidance was used to plan a biopsy trajectory to a selected area of brain with reference to a localizer grid. The procedure was performed through a 1-cm skin incision and 6-mm burr hole by use of a 9-gauge biopsy device. Five cylindrical samples (3 to 4 mm in diameter and 7 to 12 mm in length) were removed over 5 cycles of the vacuum-assisted tissue excision system, leaving approximately a 2-cm3 resection cavity. A balloon-tipped intracranial brachytherapy catheter was placed through the burr hole into the resection cavity, expanded with saline (0.9% NaCl) solution, and explanted 7 days later.
Results—4 of 5 dogs survived the procedure. The fifth died because of iatrogenic brain damage. Neurologic deficits were unilateral and focal. Twenty-four hours after surgery, all surviving dogs were ambulatory, 2 dogs exhibited ipsiversive circling, 4 had contralateral proprioceptive deficits, 3 had contralateral menace response deficits, 2 had a reduced contralateral response to noxious nasal stimulation, and 1 had dull mentation with intermittent horizontal nystagmus and ventrolateral strabismus. Neurologic status improved throughout the study period. Histologic quality of biopsy specimens was excellent.
Conclusions and Clinical Relevance—This technique enabled histologic diagnosis from high-quality biopsy specimens obtained through a minimally invasive technique and has potential applications for multimodal treatment of deep brain tumors in dogs.
Effects of isoflurane anesthesia on cerebrovascular autoregulation in horses
Authors: Brosnan Robert J. , Steffey Eugene P. , LeCouteur Richard A. , Esteller-Vico Alejandro , Vaughan Betsy , Liu Irwin K. M. 
Published: January 2011

Abstract
Objective—To test a hypothesis predicting that isoflurane would interfere with cerebrovascular autoregulation in horses and to evaluate whether increased mean arterial blood pressure (MAP) would increase cerebral blood flow and intracranial pressure (ICP) during isoflurane anesthesia.
Animals—6 healthy adult horses.
Procedures—Horses were anesthetized with isoflurane at a constant end-tidal concentration sufficient to maintain MAP at 60 mm Hg. The facial, carotid, and dorsal metatarsal arteries were catheterized for blood sample collection and pressure measurements. A sub-arachnoid transducer was used to measure ICP Fluorescent microspheres were injected through a left ventricular catheter during MAP conditions of 60 mm Hg, and blood samples were collected. This process was repeated with different-colored microspheres at the same isoflurane concentration during MAP conditions of 80 and 100 mm Hg achieved with IV administration of dobutamine. Central nervous system tissue samples were obtained after euthanasia to quantify fluorescence and calculate blood flow.
Results—Increased MAP did not increase ICP or blood flow in any of the brain tissues examined. However, values for blood flow were low for all tested brain regions except the pons and cerebellum. Spinal cord blood flow was significantly decreased at the highest MAP.
Conclusions and Clinical Relevance—Results suggested that healthy horses autoregulate blood flow in the CNS at moderate to deep planes of isoflurane anesthesia. Nonetheless, relatively low blood flows in the brain and spinal cord of anesthetized horses may increase risks for hypoperfusion and neurologic injury.
Histopathologic features of distal tarsal joint cartilage and subchondral bone in ridden and pasture-exercised horses
Authors: Tranquille Carolyne A. , Dyson Sue J. , Blunden Anthony S. , Collins Simon N. , Parkin Tim D. H. , Goodship Allen E. , Murray Rachel C. 
Published: January 2011

Abstract
Objective—To determine whether histopathologic characteristics of the osteochondral units of equine distal tarsal joints were associated with exercise history in horses without lameness.
Sample Population—30 cadaver tarsi from horses without lameness and with known exercise history were separated into 3 groups: nonridden, pasture exercise (group P); low-intensity, ridden exercise (group L); and high-intensity, elite competition exercise (group E).
Procedures—Standardized sites from the centrodistal and tarsometatarsal joints under went histologic preparation. A grading system was adapted to describe location, depth, and shape of lesions; cellular arrangement; organization at cartilage and subchondral bone (SCB) junctions; and organization of SCB. A high score signified a more severe pathological change than a low score. Exercise groups were compared by calculation of Spearman rank correlations.
Results—In the centrodistal joint, lesions were present in groups L and E but only medially. Cellular arrangement scores were higher at the dorsomedial location in group P than in groups L and E. Groups L and E had higher scores than group P for the organization of the cartilage, SCB junctions, and SCB, with higher scores at the dorsomedial location. In the tarsometatarsal joint, lesions were evident across the whole joint surface, with more severe lesions located laterally in all 3 groups. Overall, group E had higher scores for cellular arrangement and SCB organization than groups P and L.
Conclusions and Clinical Relevance—Ridden exercise may increase the risk of osteochondral lesions at distal tarsal sites predisposed to osteoarthritis relative to the risk with nonridden exercise.
Hyaluronic acid and chondrogenesis of murine bone marrow mesenchymal stem cells in chitosan sponges
Authors: Schwartz Zeev , Griffon Dominique J. , Fredericks L. Page , Lee Hae-Beom , Weng Hsin-Yi 
Published: January 2011

Abstract
Objective—To establish the dose-dependent effects of high-molecular-weight hyaluronic acid (HA) supplementation on chondrogenesis by mesenchymal stem cells (MSCs) cultured on chitosan sponges and to determine the extent to which MSC matrix production (chondrogenesis) can be influenced by incorporation of high-molecular-weight HA into chitosan scaffolds.
Sample Population—Murine MSCs derived from a multipotent bone marrow stromal precursor.
Procedures—MSCs were seeded on chitosan and chitosan-HA scaffolds in chondrogenic medium with various HA concentrations. Scanning electron microscopy, fluorescence microscopy (viability assay), and DNA quantification were used to assess cell attachment, distribution, and viability 48 hours after seeding. Constructs were cultured for 3 weeks prior to evaluation of cell distribution and chondrogenic differentiation via histologic evaluation and quantification of DNA, glycosaminoglycan, and collagen II.
Results—48 hours after MSC seeding, cell viability and DNA content were similar among groups. Three weeks after seeding, HA supplementation of the culture medium improved matrix production in a dose-dependent manner, as indicated by matrix glycosaminoglycan and collagen II concentrations. The scaffold composition, however, had no significant effect on matrix production.
Conclusions and Clinical Relevance—High-molecular-weight HA supplementation in culture medium had a dose-dependent effect on matrix production and thus chondrogenic differentiation of MSCs cultured on chitosan sponges. The addition of HA in the surrounding fluid during chondrogenesis should improve cartilage production and may be useful for producing engineered cartilage tissues.
Influence of blood collection technique on platelet function and coagulation variables in dogs
Authors: Bauer Natali B. , Er Elif , Moritz Andreas 
Published: January 2011

Abstract
Objective—To investigate the influence of diameter of the catheter and blood collection technique on platelet function and variables reflecting secondary hemostasis, physiologic anticoagulation, and fibrinolysis in dogs.
Animals—6 healthy Beagles.
Procedures—Blood samples were collected with 20- and 18-gauge venous catheters immediately after catheters were inserted in a peripheral vein, through a 14-gauge central venous catheter that had been placed via the Seldinger technique in a jugular vein < 30 minutes before sample collection, and through a 13-gauge central venous catheter placed via a catheter-through-the-needle technique < 30 minutes before sample collection (techniques 1 to 4, respectively). Platelet function was assessed in hirudin-anticoagulated whole blood via an impedance-based aggregometer with collagen (0.8, 0.4, 0.2, 0.1, and 0.05 μg/mL) as an inductor. Kaolin-activated thromboelastography variables were determined in citrated whole blood. Prothrombin time, activated partial thromboplastin time, fibrinogen and fibrin D-dimer concentrations, and activity of factor VIII, antithrombin, protein C, and protein S were assessed automatically in citrated plasma.
Results—At 0.05 μg of collagen/mL, the highest median rate of aggregation was observed for collection techniques 2 and 3 with 4.3 (range, 2.5 to 6.5) and 3.7 (range, 2.8 to 8.3) aggregation units/min; however, these values were not significantly different from values for the other collection techniques. Generally, sample collection technique did not have a significant impact on results of coagulation variables investigated.
Conclusions and Clinical Relevance—Various blood collection techniques can be used to obtain samples for coagulation testing.
Adhesion phenotypes of pigs of Chinese and Western breeds and a White Duroc-Erhualian crossbreed with regard to susceptibility to enterotoxigenic Escherichia coli with fimbrial adhesins K99, 987P, and F41
Authors: Yan Xueming , Huang Xiang , Ren Jun , Ouyang Jing , Yang Ming , Han Pengfei , Huang Lusheng 
Published: January 2011

Abstract
Objective—To investigate adhesion phenotypes of pigs of Chinese and Western breeds and a specific crossbreed with regard to enterotoxigenic Escherichia coli (ETEC) with fimbrial adhesins K99 (F5), 987P (F6), and F41 (F7).
Animals—Purebred 6- to 8-week-old pigs of 3 Western breeds introduced into China (n = 144) and 12 Chinese breeds (148) and 1,330 adult White Duroc-Erhualian crossbred pigs.
Procedures—Brush border preparations were prepared from jejunal specimens collected from each pig following euthanasia. Each preparation was incubated with ETEC strains that had fimbrial adhesins K99, 987R or F41; an ETEC K88− strain was used as a negative control sample. The mean number of brush border-bound bacteria in aliquots of the bacteria-brush border suspensions (determined via phase-contrast microscopy) was used to determine each pig's adhesion phenotype for ETEC K99, 987R and F41 strains; the phenotype was classified as adhesive (susceptible) if ≥ 10% of examined brush borders bound > 2 bacteria.
Results—Most purebred and crossbred pigs had nonadhesive phenotypes with regard to ETEC K99 and 987P strains. For the F41 strain, 34.9% and 65.1% of all purebred pigs had adhesive and nonadhesive phenotypes, respectively; among crossbred pigs, these values were 39.2% and 60.8%, respectively. The percentage of pigs with the F41 adhesive phenotype was higher among Western breeds than it was among Chinese breeds (38.9% vs 31.1%).
Conclusions and Clinical Relevance—Results suggested that the ETEC F41 strain, but not the K99 or 987P strain, might be a cause of diarrhea in 6- to 8-week-old pigs in China.