bluuebunny/crossref_metadata_2025 huggingface dataset:
Cues for acoustic detection of prey: insect rustling sounds and the influence of walking substrate
Authors: Goerlitz Holger R. , Greif Stefan , Siemers Björn M.
Published: August 2008

When insects walk, they generally produce sounds. These can reveal the walkers' presence and location to potential predators such as owls, bats and nocturnal primates. Additionally, predators might extract information on taxon, palatability, size or profitability from the rustling sounds. In contrast to ear morphology, hearing physiology and psychoacoustics of acoustically oriented predators, little attention has hitherto been paid to the acoustic structure and information content of prey sounds. An important element in the ecology of acoustic prey detection remained virtually unexplored: the influence of the substrate type on rustling sounds. In this study, we analysed amplitude and frequency parameters from insects walking on various natural substrates, in both Germany (Carabus beetles) and Madagascar (various beetles and cockroaches). The data show that rustling sound amplitude and frequency content depend on substrate type. On moist substrates arthropods produced less intense and less broadband rustling sounds than on dry substrates. Sound pressure level was reduced by about 6 dB,halving the detection range for the predator. For a given insect, rustling sound amplitude increased with walking speed. Finally, we found that the previously established correlation of arthropod size and rustling amplitude holds across multiple substrates. Based on these data, we provide for the first time estimates of realistic detection distances in the field. These distances range from below 1 m to over 13 m, depending on the substrate,insect mass, walking speed and background noise level. These estimates are crucial for an understanding of the foraging ecology, foraging efficiency and sensory ecology of acoustic predators.
Exploration and navigation in the blind mole rat (Spalax ehrenbergi): global calibration as a primer of spatial representation
Authors: Avni Reut , Tzvaigrach Yael , Eilam David
Published: August 2008

The aim of this study was to uncover the process of initial spatial mapping of the environment. For this, blind mole rats (Spalax ehrenbergi),were tested in an unfamiliar square arena, in order to reveal how they construct a spatial representation. The mole rats first displayed a build-up phase, in which they gradually formed a path along the perimeter while travelling slowly, frequently pausing and repeating previously travelled segments of the path. This behaviour was followed by a free-travel phase, in which the mole rats appeared to locomote smoothly along the perimeter and through the centre of the arena while travelling faster with fewer stops or repetitions of path segments. Familiarity with the environment was reflected in local shortcuts at the arena corners and global shortcuts (crosscuts)through the arena centre. We suggest that scanning the perimeter throughout the build-up phase constitute a process of calibration, i.e. forming an initial representation of the size and perhaps the shape of the environment– a sort of basic global map. We further suggest that this calibration is later used for navigation, as indicated by the emergence of global crosscuts in the subsequent phase. Further investigation of the build-up phase, e.g. by manipulating environment size, might provide additional insight into the course of establishment of global environment representation(mapping).
The effects of gravity on human walking: a new test of the dynamic similarity hypothesis using a predictive model
Authors: Raichlen David A.
Published: August 2008

The dynamic similarity hypothesis (DSH) suggests that differences in animal locomotor biomechanics are due mostly to differences in size. According to the DSH, when the ratios of inertial to gravitational forces are equal between two animals that differ in size [e.g. at equal Froude numbers, where Froude =velocity2/(gravity × hip height)], their movements can be made similar by multiplying all time durations by one constant, all forces by a second constant and all linear distances by a third constant. The DSH has been generally supported by numerous comparative studies showing that as inertial forces differ (i.e. differences in the centripetal force acting on the animal due to variation in hip heights), animals walk with dynamic similarity. However, humans walking in simulated reduced gravity do not walk with dynamically similar kinematics. The simulated gravity experiments did not completely account for the effects of gravity on all body segments, and the importance of gravity in the DSH requires further examination. This study uses a kinematic model to predict the effects of gravity on human locomotion,taking into account both the effects of gravitational forces on the upper body and on the limbs. Results show that dynamic similarity is maintained in altered gravitational environments. Thus, the DSH does account for differences in the inertial forces governing locomotion (e.g. differences in hip height)as well as differences in the gravitational forces governing locomotion.
Interactions between eIF4AI and its accessory factors eIF4B and eIF4H
Authors: Rozovsky Nadja , Butterworth Aimee C. , Moore Melissa J.
Published: August 2008

Ribonucleoprotein complexes (RNP) remodeling by DEAD-box proteins is required at all stages of cellular RNA metabolism. These proteins are composed of a core helicase domain lacking sequence specificity; flanking protein sequences or accessory proteins target and affect the core's activity. Here we examined the interaction of eukaryotic initiation factor 4AI (eIF4AI), the founding member of the DEAD-box family, with two accessory factors, eIF4B and eIF4H. We find that eIF4AI forms a stable complex with RNA in the presence of AMPPNP and that eIF4B or eIF4H can add to this complex, also dependent on AMPPNP. For both accessory factors, the minimal stable complex with eIF4AI appears to have 1:1 protein stoichiometry. However, because eIF4B and eIF4H share a common binding site on eIF4AI, their interactions are mutually exclusive. The eIF4AI:eIF4B and eIF4AI:eIF4H complexes have the same RNase resistant footprint as does eIF4AI alone (9–10 nucleotides [nt]). In contrast, in a selective RNA binding experiment, eIF4AI in complex with either eIF4B or eIF4H preferentially bound RNAs much longer than those bound by eIF4AI alone (30–33 versus 17 nt, respectively). The differences between the RNase resistant footprints and the preferred RNA binding site sizes are discussed, and a model is proposed in which eIF4B and eIF4H contribute to RNA affinity of the complex through weak interactions not detectable in structural assays. Our findings mirror and expand on recent biochemical and structural data regarding the interaction of eIF4AI's close relative eIF4AIII with its accessory protein MLN51.
Site-specific crosslinking of human microRNPs to RNA targets
Authors: Kirino Yohei , Mourelatos Zissimos
Published: August 2008

MicroRNAs (miRNAs) regulate the expression of numerous genes and are implicated in the pathogenesis of many human diseases. miRNAs act as specificity determinants to guide deposition of microRNPs (miRNPs) onto miRNA recognition elements (MREs) that are found in mRNA targets. We have adapted a site-specific crosslinking approach, previously used in the analysis of splicing, to interrogate protein factors that physically associate with MREs in human cells. We find that Ago proteins are the only proteins that bind to the MRE in a miRNA-dependent manner. Our method may be used in various experimental systems to analyze protein factors that influence MRE accessibility by miRNAs and the composition of MRE-bound miRNPs.
A cell-based screen for splicing regulators identifies hnRNP LL as a distinct signal-induced repressor ofCD45variable exon 4
Authors: Topp Justin D. , Jackson Jason , Melton Alexis A. , Lynch Kristen W.
Published: August 2008

The humanCD45gene encodes a protein–tyrosine phosphatase that exhibits differential isoform expression in resting and activated T cells due to alternative splicing of three variable exons. Previously, we have used biochemical methods to identify two regulatory proteins, hnRNP L and PSF, which contribute to the activation-induced skipping ofCD45via the ESS1 regulatory element in variable exon 4. Here we report the identification of a thirdCD45regulatory factor, hnRNP L-like (hnRNP LL), via a cell-based screen for clonal variants that exhibit an activation-like phenotype ofCD45splicing even under resting conditions. Microarray analysis of two splicing-altered clones revealed increased expression of hnRNP LL relative to wild-type cells. We further demonstrate that both the expression of hnRNP LL protein and its binding to ESS1 are up-regulated in wild-type cells upon activation. Forced overexpression of hnRNP LL in wild-type cells results in an increase in exon repression, while knock-down of hnRNP LL eliminates activation-induced exon skipping. Interestingly, analysis of the binding of hnRNP L and hnRNP LL to mutants of ESS1 reveals that these proteins have overlapping, but distinct binding requirements. Together, these data establish that hnRNP LL plays a critical and unique role in the signal-induced regulation ofCD45and demonstrate the utility of cell-based screens for the identification of novel splicing regulatory factors.
tRNA cleavage is a conserved response to oxidative stress in eukaryotes
Authors: Thompson Debrah M. , Lu Cheng , Green Pamela J. , Parker Roy
Published: August 2008

Recent results have identified a diversity of small RNAs in a wide range of organisms. In this work, we demonstrate that Saccharomyces cerevisiae contains a small RNA population consisting primarily of tRNA halves and rRNA fragments. Both 5′ and 3′ fragments of tRNAs are detectable by Northern blot analysis, suggesting a process of endonucleolytic cleavage. tRNA and rRNA fragment production in yeast is most pronounced during oxidative stress conditions, especially during entry into stationary phase. Similar tRNA fragments are also observed in human cell lines and in plants during oxidative stress. These results demonstrate that tRNA cleavage is a conserved aspect of the response to oxidative stress.
Cumulative Dominance and Heuristic Performance in Binary Multiattribute Choice
Authors: Baucells Manel , Carrasco Juan A. , Hogarth Robin M.
Published: August 2008

We study the effectiveness of simple heuristics in multiattribute decision making. We consider the case of an additive separable utility function with nonnegative, nonincreasing attribute weights. In this case, cumulative dominance ensures that the so-called cumulative dominance compliant heuristics will choose a best alternative. For the case of binary attribute values and under two probabilistic models of the decision environment generalizing a simple Bernoulli model, we obtain the probabilities of simple and cumulative dominance. In contrast with the probability of simple dominance, the probability of cumulative dominance is shown to be large in many cases, explaining the effectiveness of cumulative dominance compliant heuristics in those cases. Additionally, for the subclass of the so-called fully cumulative dominance compliant heuristics, we obtain an upper bound for the expected loss that only depends on the weights being nonnegative and nonincreasing. The low values of the upper bound for cases in which the probability of cumulative dominance is not large provide an additional explanation for the effectiveness of fully cumulative dominance compliant heuristics. Examples of cumulative dominance compliant heuristics and fully cumulative dominance compliant heuristics are discussed, including the deterministic elimination by aspects (DEBA) heuristic that motivated our work.
Scoring Rules, Generalized Entropy, and Utility Maximization
Authors: Jose Victor Richmond R. , Nau Robert F. , Winkler Robert L.
Published: August 2008

Information measures arise in many disciplines, including forecasting (where scoring rules are used to provide incentives for probability estimation), signal processing (where information gain is measured in physical units of relative entropy), decision analysis (where new information can lead to improved decisions), and finance (where investors optimize portfolios based on their private information and risk preferences). In this paper, we generalize the two most commonly used parametric families of scoring rules and demonstrate their relation to well-known generalized entropies and utility functions, shedding new light on the characteristics of alternative scoring rules as well as duality relationships between utility maximization and entropy minimization. In particular, we show that weighted forms of the pseudospherical and power scoring rules correspond exactly to measures of relative entropy (divergence) with convenient properties, and they also correspond exactly to the solutions of expected utility maximization problems in which a risk-averse decision maker whose utility function belongs to the linear-risk-tolerance family interacts with a risk-neutral betting opponent or a complete market for contingent claims in either a one-period or a two-period setting. When the market is incomplete, the corresponding problems of maximizing linear-risk-tolerance utility with the risk-tolerance coefficient β are the duals of the problems of minimizing the pseudospherical or power divergence of order β between the decision maker's subjective probability distribution and the set of risk-neutral distributions that support asset prices.
Technical Note—Optimal Dynamic Joint Inventory-Pricing Control for Multiplicative Demand with Fixed Order Costs and Lost Sales
Authors: Song Yuyue , Ray Saibal , Boyaci Tamer
Published: August 2008

This note studies the optimal dynamic decision-making problem for a retailer in a price-sensitive, multiplicative demand framework. Our model incorporates lost sales, holding cost, fixed and variable procurement costs, as well as salvage value. We characterize the structure of the retailer's (discounted) expected profit-maximizing dynamic inventory policy for both finite and infinite selling horizon problems.
Serum Total Prolactin and Monomeric Prolactin Reference Intervals Determined by Precipitation with Polyethylene Glycol: Evaluation and Validation on Common ImmunoAssay Platforms
Authors: Beltran Luisa , Fahie-Wilson Michael N , McKenna T Joseph , Kavanagh Lucille , Smith Thomas P
Published: August 2008

Background: Macroprolactin is an important source of immunoassay interference that commonly leads to misdiagnosis and mismanagement of hyperprolactinemic patients. We used the predominant immunoassay platforms for prolactin to assay serum samples treated with polyethylene glycol (PEG) and establish and validate reference intervals for total and monomeric prolactin.

Methods: We used the Architect (Abbott), ADVIA Centaur and Immulite (Siemens Diagnostics), Access (Beckman Coulter), Elecsys (Roche Diagnostics), and AIA (Tosoh) analyzers with samples from healthy males (n = 53) and females (n = 93) to derive parametric reference intervals for total and post-PEG monomeric prolactin. Concentrations of immunoreactive prolactin isoforms in serum samples from healthy individuals were established by gel filtration chromatography (GFC). We then used samples from 22 individuals whose hyperprolactinemia was entirely attributable to macroprolactin and 32 patients with true hyperprolactinemia to compare patient classifications and prolactin concentrations measured by GFC with the newly derived post-PEG reference intervals.

Results: Parametric reference intervals for post-PEG prolactin in male and female serum samples, respectively, were (in mIU/L): 61–196, 66–278 (Centaur); 63–245, 75–381 (Elecsys); 70–301, 92–469 (Access); 72–229, 79–347 (Architect); 73–247, 83–383 (AIA); and 78–263, 85–394 (Immulite). Concordance between GFC and immunoassay-specific post-PEG reference intervals was observed in 311 of 324 cases and for 31 of 32 patients with true hyperprolactinemia and 17 of 22 patients with macroprolactinemia. Results leading to misclassification occurred in a few analyzers for 5 macroprolactinemia patient samples with relatively minor increases in post-PEG prolactin (mean 61 mIU/L).

Conclusions: Our validated normative reference data for sera pretreated with PEG and analyzed on the most commonly used immunoassay platforms should facilitate the more widespread introduction of macroprolactin screening by clinical laboratories.
Die moderne Staatsbürgerschaft und ihre Grenzen: Anmerkungen zu T. H. Marshalls „citizenship”-Konzept (Modern Citizenship and its Limits: Notes on T. H. Marshall's Concept of Citizenship)
Authors: Fahrmeir Andreas
Published: August 2008

In einer kritischen Auseinandersetzung mit T. H. Marshalls klassischer Vorlesung „Citizenship and Social Class” argumentiert der Beitrag, daß die Formen und Grenzen des Verbands der Staatsbürger, die für Marshall 1949 keine Rolle spielten, einer detaillierteren Betrachtung wert sind. Eine empirisch genaue Bestimmung der Gruppen, welche von Staatsbürgerschaftsrechten profitierten, und eine Erforschung der Institutionen, welche über Inklusion und Exklusion entschieden, verspricht neue Erkenntnisse über die Bedeutung des Zentral- oder Nationalstaates im Vergleich mit der lokalen Verwaltung ebenso wie eine Präzision des auch durch die Marshall-Rezeption aufgeweichten, für die Forschungsdebatte aber zentralen Begriffs citizenship.
Permselectivity of blood follicle barriers in mouse ovaries of the mifepristone-induced polycystic ovary model revealed by in vivo cryotechnique
Authors: Zhou Hong , Ohno Nobuhiko , Terada Nobuo , Saitoh Sei , Naito Ichiro , Ohno Shinichi
Published: August 2008

Despite the potential association of polycystic ovary (PCO) syndrome with hemodynamic changes, follicular microenvironment and the involvement of blood follicle barriers (BFB), a histopathological examination has been hampered by artifacts caused by conventional preparation methods. In this study, mouse ovaries of a mifepristone-induced PCO model were morphologically and immunohistochemically examined by in vivo cryotechnique (IVCT), which prevents those technical artifacts. Ovarian specimens of PCO model mice were prepared by IVCT or the conventional perfusion fixation after s.c. injection of mifepristone. Their histology and immunolocalization of plasma proteins, including albumin (molecular mass, 69 kDa), immunoglobulin G (IgG, 150 kDa), inter-α-trypsin inhibitor (ITI, 220 kDa), fibrinogen (340 kDa), and IgM (900 kDa), were examined. In the PCO model, enlarged blood vessels with abundant blood flow were observed in addition to cystic follicles with degenerative membrana granulosa. The immunolocalization of albumin and IgM in the PCO model were similar to those in normal mice. Albumin immunolocalized in the blood vessels, interstitium or follicles, and IgM was mostly restricted within the blood vessels. In contrast, immunolocalization of IgG, ITI, and fibrinogen changed in the PCO model. Both IgG and ITI were clearly blocked by follicular basement membranes, and hardly observed in the membrana granulosa, though fibrinogen was mostly observed within blood vessels. These findings suggest that increased blood flow and enhanced selectivity of molecular permeation through the BFB are prominent features in the PCO ovaries, and changes in hemodynamic conditions and permselectivity of BFB are involved in the pathogenesis and pathophysiology of PCO syndrome.
A Molecular Selection Index Method Based on Eigenanalysis
Authors: Cerón-Rojas J Jesús , Castillo-González Fernando , Sahagún-Castellanos Jaime , Santacruz-Varela Amalio , Benítez-Riquelme Ignacio , Crossa José
Published: August 2008

The traditional molecular selection index (MSI) employed in marker-assisted selection maximizes the selection response by combining information on molecular markers linked to quantitative trait loci (QTL) and phenotypic values of the traits of the individuals of interest. This study proposes an MSI based on an eigenanalysis method (molecular eigen selection index method, MESIM), where the first eigenvector is used as a selection index criterion, and its elements determine the proportion of the trait's contribution to the selection index. This article develops the theoretical framework of MESIM. Simulation results show that the genotypic means and the expected selection response from MESIM for each trait are equal to or greater than those from the traditional MSI. When several traits are simultaneously selected, MESIM performs well for traits with relatively low heritability. The main advantages of MESIM over the traditional molecular selection index are that its statistical sampling properties are known and that it does not require economic weights and thus can be used in practical applications when all or some of the traits need to be improved simultaneously.
Natural Genetic Variation ofArabidopsis thalianaIs Geographically Structured in the Iberian Peninsula
Authors: Picó F Xavier , Méndez-Vigo Belén , Martínez-Zapater José M , Alonso-Blanco Carlos
Published: August 2008

To understand the demographic history of Arabidopsis thaliana within its native geographical range, we have studied its genetic structure in the Iberian Peninsula region. We have analyzed the amount and spatial distribution of A. thaliana genetic variation by genotyping 268 individuals sampled in 100 natural populations from the Iberian Peninsula. Analyses of 175 individuals from 7 of these populations, with 20 chloroplast and nuclear microsatellite loci and 109 common single nucleotide polymorphisms, show significant population differentiation and isolation by distance. In addition, analyses of one genotype from 100 populations detected significant isolation by distance over the entire Iberian Peninsula, as well as among six Iberian subregions. Analyses of these 100 genotypes with different model-based clustering algorithms inferred four genetic clusters, which show a clear-cut geographical differentiation pattern. On the other hand, clustering analysis of a worldwide sample showed a west–east Eurasian longitudinal spatial gradient of the commonest Iberian genetic cluster. These results indicate that A. thaliana genetic variation displays significant regional structure and consistently support the hypothesis that Iberia has been a glacial refugium for A. thaliana. Furthermore, the Iberian geographical structure indicates a complex regional population dynamics, suggesting that this region contained multiple Pleistocene refugia with a different contribution to the postglacial colonization of Europe.
Intraspecific Phylogeographic Genomics From Multiple Complete mtDNA Genomes in Atlantic Cod (Gadus morhua): Origins of the “Codmother,” Transatlantic Vicariance and Midglacial Population Expansion
Authors: Carr Steven M , Marshall H Dawn
Published: August 2008

On the basis of multiple complete mitochondrial DNA genome sequences, we describe the temporal phylogeography of Atlantic cod (Gadus morhua), a lineage that has undergone a complex pattern of vicariant evolution, postglacial demographic shifts, and historic sharp population declines due to fishing and/or environmental shifts. Each of 32 fish from four spawning aggregations from the northwest Atlantic and Norway has a unique mtDNA sequence, which differs by 6–60 substitutions. Phylogenetic analysis identifies six major haplogroups that range in age from 37 to 75 KYA. The widespread haplotype identified by previous single-locus analyses at the center of a “star phylogeny” is shown to be a paraphyletic assemblage of genome lineages. The coalescent that includes all cod occurs 162 KYA. The most basal clade comprises two fish from the western Atlantic. The most recent superclade that includes all fish examined from Norway, and which includes 84% of all fish examined, dates to 128 KYA at the Sangamon/Würm interglacial, when ocean depths on continental shelves would have favored transcontinental movement. The pairwise mismatch distribution dates population expansion of this superclade to the middle of the Wisconsinan/Weichsel glaciation 59 KYA, rather than to a postglacial emergence from a marine refugium 12 KYA, or to more recent historic events. We discuss alternative scenarios for the expansion and distribution of the descendants of the “codmother” in the North Atlantic. Mitochondrial phylogenomic analyses generate highly resolved trees that enable fine-scale tests of temporal hypotheses with an accuracy not possible with single-locus methods.
Thelytokous Parthenogenesis in Unmated Queen Honeybees (Apis mellifera capensis): Central Fusion and High Recombination Rates
Authors: Oldroyd Benjamin P , Allsopp Michael H , Gloag Rosalyn S , Lim Julianne , Jordan Lyndon A , Beekman Madeleine
Published: August 2008

The subspecies of honeybee indigenous to the Cape region of South Africa, Apis mellifera capensis, is unique because a high proportion of unmated workers can lay eggs that develop into females via thelytokous parthenogenesis involving central fusion of meiotic products. This ability allows pseudoclonal lineages of workers to establish, which are presently widespread as reproductive parasites within the honeybee populations of South Africa. Successful long-term propagation of a parthenogen requires the maintenance of heterozygosity at the sex locus, which in honeybees must be heterozygous for the expression of female traits. Thus, in successful lineages of parasitic workers, recombination events are reduced by an order of magnitude relative to meiosis in queens of other honeybee subspecies. Here we show that in unmated A. m. capensis queens treated to induce oviposition, no such reduction in recombination occurs, indicating that thelytoky and reduced recombination are not controlled by the same gene. Our virgin queens were able to lay both arrhenotokous male-producing haploid eggs and thelytokous female-producing diploid eggs at the same time, with evidence that they have some voluntary control over which kind of egg was laid. If so, they are able to influence the kind of second-division meiosis that occurs in their eggs post partum.
Multilocus Patterns of Nucleotide Polymorphism and the Demographic History of Populus tremula
Authors: Ingvarsson Pär K
Published: August 2008

I have studied nucleotide polymorphism and linkage disequilibrium using multilocus data from 77 fragments, with an average length of fragments of 550 bp, in the deciduous tree Populus tremula (Salicaceae). The frequency spectrum across loci showed a modest excess of mutations segregating at low frequency and a marked excess of high-frequency derived mutations at silent sites, relative to neutral expectations. These excesses were also seen at replacement sites, but were not so pronounced for high-frequency derived mutations. There was a marked excess of low-frequency mutations at replacement sites, likely indicating deleterious amino acid-changing mutations that segregate at low frequencies in P. tremula. I used approximate Bayesian computation (ABC) to evaluate a number of different demographic scenarios and to estimate parameters for the best-fitting model. The data were found to be consistent with a historical reduction in the effective population size of P. tremula through a bottleneck. The timing inferred for this bottleneck is largely consistent with geological data and with data from several other long-lived plant species. The results show that P. tremula harbors substantial levels of nucleotide polymorphism with the posterior mode of the scaled mutation rate, θ = 0.0177 across loci. The ABC analyses also provided an estimate of the scaled recombination rate that indicates that recombination rates in P. tremula are likely to be 2–10 times higher than the mutation rate. This study reinforces the notion that linkage disequilibrium is low and decays to negligible levels within a few hundred base pairs in P. tremula.
Investigation ofMcp1as a Quantitative Trait Gene for Prion Disease Incubation Time in Mouse
Authors: O'Shea Marie , Maytham Emma G , Linehan Jackie M , Brandner Sebastian , Collinge John , Lloyd Sarah E
Published: August 2008

The genetic basis of prion disease incubation time is principally determined by polymorphisms in the prion protein gene, Prnp. However, it is now known that other genetic factors are important. Several quantitative trait loci (QTL) have been identified across the genome including a broad region of linkage on Mmu11. Monocyte chemoattractant protein 1 (MCP-1) maps to this region and has been associated with microglial activation and reduced survival in the ME7 mouse scrapie model of prion disease. We have identified 10 polymorphisms, 3 of which are nonsynonomous, in Mcp1 between “long” (CAST) and “short” (SJL or NZW) incubation-time mouse strains. Crosses between these strains and Mcp1−/− mice inoculated with the Chandler/RML mouse scrapie prion strain formed the basis of a quantitative complementation test. In these models loss of Mcp1 did not show an increase in incubation time suggesting that the effects of Mcp1 may be specific to the ME7 prion strain and that Mcp1 does not contribute to the QTL described on Mmu11.
The Ku Complex in Silencing the Cryptic Mating-Type Loci ofSaccharomyces cerevisiae
Authors: Patterson Erin E , Fox Catherine A
Published: August 2008

Sir1 establishes transcriptional silencing at the cryptic mating-type loci HMR and HML (HM loci) by recruiting the three other Sir proteins, Sir2, -3, and -4, that function directly in silenced chromatin. However, SIR1-independent mechanisms also contribute to recruiting the Sir2–4 proteins to the HM loci. A screen to elucidate SIR1-independent mechanisms that establish HMR silencing identified a mutation in YKU80. The role for Ku in silencing both HMR and HML was masked by SIR1. Ku's role in silencing the HM loci was distinct from its shared role with the nuclear architecture protein Esc1 in tethering the HM loci and telomeres to the nuclear periphery. The ability of high-copy SIR4 to rescue HMR silencing defects in sir1Δ cells required Ku, and chromatin immunoprecipitation (ChIP) experiments provided evidence that Ku contributed to Sir4's physical association with the HM loci in vivo. Additional ChIP experiments provided evidence that Ku functioned directly at the HM loci. Thus Ku and Sir1 had overlapping roles in silencing the HM loci.
Modulation of Inflammatory Responses After Global Ischemia by Transplanted Umbilical Cord Matrix Stem Cells
Authors: Hirko Aaron C. , Dallasen Renee , Jomura Sachiko , Xu Yan
Published: August 2008

Rat umbilical cord matrix (RUCM) cells are stem-cell-like cells and have been shown to reduce neuronal loss in the selectively vulnerable brain regions after cardiac arrest (CA). Here, we investigate whether this protection is mediated by the RUCM cells' modulation of the postischemia inflammation responses, which have long been implicated as a secondary mechanism of injury following ischemia. Brain sections were examined immunohistochemically for glial fibrillary acidic protein (GFAP), vimentin, and nestin as markers for astroglia and reactive astrogliosis, Ricinus Communis Agglutinin-1 (RCA-1) as a marker for microglia, and Ki67 as a marker for cell proliferation. Rats were randomly assigned to six experimental groups: (1) 8-minute CA without treatment, (2) 8-minute CA pre-treated with culture medium injection, (3) 8-minute CA pre-treated with RUCM cells, (4) sham-operated CA, (5) medium injection without CA, and (6) RUCM cell transplantation without CA. Groups 1–3 have significantly higher Ki67+ cell counts and higher GFAP+ immunoreactivity in the hippocampal Cornu Ammonis layer 1 (CA1) region compared to groups 4–6, irrespective of treatment. Groups 1 and 2 have highly elevated GFAP+, vimentin+, and nestin+ immunoreactivity, indicating reactive astrogliosis. Strikingly, RUCM cell treatment nearly completely inhibited the appearance of vimentin+ and greatly reduced nestin+ reactive astrocytes. RUCM cell treatment also greatly reduced RCA-1 staining, which is found to strongly correlate with the neuronal loss in the CA1 region. Our study indicates that treatment with stem-cell-like RUCM cells modulates the inflammatory response to global ischemia and renders neuronal protection by preventing permanent damage to the selectively vulnerable astrocytes in the CA1 region.

Disclosure of potential conflicts of interest is found at the end of this article.
Enrichment and Differentiation of Human Germ-Like Cells Mediated by Feeder Cells and Basic Fibroblast Growth Factor Signaling
Authors: West Franklin D. , Machacek Dave W. , Boyd Nolan L. , Pandiyan Kurinji , Robbins Kelly R. , Stice Steven L.
Published: August 2008

Human embryonic stem cells (hESCs) have recently demonstrated the potential for differentiation into germ-like cells in vitro. This provides a novel model for understanding human germ cell development and human infertility. Mouse embryonic fibroblast (MEF) feeders and basic fibroblast growth factor (bFGF) are two sources of signaling that are essential for primary culture of germ cells, yet their role has not been examined in the derivation of germ-like cells from hESCs. Here protein and gene expression demonstrated that both MEF feeders and bFGF can significantly enrich germ cell differentiation from hESCs. Under enriched differentiation conditions, flow cytometry analysis proved 69% of cells to be positive for DDX4 and POU5F1 protein expression, consistent with the germ cell lineage. Importantly, removal of bFGF from feeder-free cultures resulted in a 50% decrease in POU5F1- and DDX4-positive cells. Quantitative reverse transcription-polymerase chain reaction analysis established that bFGF signaling resulted in an upregulation of genes involved in germ cell differentiation with or without feeders; however, feeder conditions caused significant upregulation of premigratory/migratory (Ifitm3, DAZL, NANOG, and POU5F1) and postmigratory (PIWIL2, PUM2) genes, along with the meiotic markers SYCP3 and MLH1. After further differentiation, >90% of cells expressed the meiotic proteins SYCP3 and MLH1. This is the first demonstration that signaling from MEF feeders and bFGF can induce a highly enriched population of germ-like cells derived from hESCs, thus providing a critically needed model for further investigation of human germ cell development and signaling.

Disclosure of potential conflicts of interest is found at the end of this article.
Long-term moderate ethanol consumption restores insulin sensitivity in high-fat-fed rats by increasing SLC2A4 (GLUT4) in the adipose tissue by AMP-activated protein kinase activation
Authors: Feng Li , Gao Ling , Guan Qingbo , Hou Xiaolei , Wan Qiang , Wang Xiangdong , Zhao Jiajun
Published: August 2008

The sole effect of either saturated fatty acid or moderate ethanol consumption on SLC2A4 (GLUT4) expression is widely reported but the combined effects of them remain obscure. Here, we observed their combined effects on SLC2A4 expression, explored the underlying mechanism mediated by AMP-activated protein kinase α (PRKAA2) and myocyte enhancer factor 2 (MEF2) both in vivo and in vitro. In the in vivo experiments, 36 male Wistar rats, divided into three groups, were fed with normal diet, high-fat (HF) diet, or HF diet plus ethanol for 22 weeks. We measured the expressions of total-PRKAA2 (T-PRKAA2), phosphorylated-PRKAA2 (pPRKAA2, activated form of PRKAA2), MEF2, and SLC2A4 in epididymal adipose tissues. In the in vitro experiments, primary adipocytes, isolated from normal Wistar rats, were incubated in the presence or absence of palmitate, ethanol, and compound C (an PRKAA2 inhibitor) for 1 h. Thereafter, T-PRKAA2, pPRKAA2, MEF2, and SLC2A4 expressions were measured. We found that both HF diet and in vitro exposition to palmitate impaired SLC2A4 expression in rat adipocytes with a parallel reduction in PRKAA2 activation and MEF2 expression. This impairment was reversed by ethanol administration. We further demonstrated that ethanol-mediated PRKAA2 activation stimulates MEF2 and SLC2A4 expressions in adipocytes, as evidenced by compound C blockade of these effects. In summary, long-term moderate ethanol consumption reversed the adverse effect of saturated fatty acid on SLC2A4 expression in adipocytes, which was likely to be a result of PRKAA2 activation and subsequent up-regulation of MEF2 and SLC2A4 expressions.
In Vitro Optimization of Dexamethasone Phosphate Delivery by Iontophoresis
Authors: Sylvestre Jean-Philippe , Guy Richard H , Delgado-Charro M Begoña
Published: August 2008

Background and Purpose

This study was designed to evaluate the effects of competing ions and electroosmosis on the transdermal iontophoresis of dexamethasone phosphate (Dex-Phos) and to identify the optimal conditions for its delivery.

Methods

The experiments were performed using pig skin, in side-by-side diffusion cells (0.78 cm2), passing a constant current of 0.3 mA via Ag-AgCl electrodes. Dex-Phos transport was quantified for donor solutions (anodal and cathodal) containing different drug concentrations, with and without background electrolyte. Electrotransport of co-ion, citrate, and counterions Na+ and K+ also was quantified. The contribution of electroosmosis was evaluated by measuring the transport of the neutral marker (mannitol).

Results

Electromigration was the dominant mechanism of drug iontophoresis, and reduction in electroosmotic flow directed against the cathodic delivery of Dex-Phos did not improve drug delivery. The Dex-Phos flux from the cathode was found to be optimal (transport number of ∼0.012) when background electrolyte was excluded from the formulation. In this case, transport of the drug is limited principally by the competition with counterions (mainly Na+ with a transport number of ∼0.8) and the mobility of the drug in the membrane.

Discussion and Conclusion

Dex-Phos must be delivered from the cathode and formulated rationally, excluding mobile co-anions, to achieve optimal iontophoretic delivery.
Real-time terahertz imaging for art conservation science
Authors: Fukunaga K. , Sekine N. , Hosako I. , Oda N. , Yoneyama H. , Sudoh T.
Published: August 2008

A new real-time terahertz imaging system has been developed by using a quantum cascade laser source and a microbolometer focal plane detector array. The application to non-invasive analyses of cultural heritage is demonstrated with an oil paint specimen. The experimental results suggested that the terahertz imaging system can identify materials based on a spectral database with a spatial resolution of about 300 µm. The transmission imaging indicated the difference between natural and artificial ultramarine pigments. Since the size of the system is similar to a common portable infrared camera, it can be used at the place where the object is located, such as museums, and can contribute to conservation activities, such as drying process monitoring. This real-time, small, non-invasive terahertz imaging system can be used in various fundamental research fields and practical industries.
Oral Narrative Genres as Dialogic Resources for Classroom Literature Study: A Contextualized Case Study of Conversational Narrative Discussion
Authors: Juzwik Mary M. , Nystrand Martin , Kelly Sean , Sherry Michael B.
Published: August 2008

Five questions guided a case study exploring the relationship between oral narrative and discussion in middle school literature study: (a) Relative to similar classrooms in a large-scale study, how can overall literature instruction be characterized? (b) Relative to similar classrooms in a large-scale study, how well do students achieve in the focal classroom? (c) What, if any, are the links between oral narrative and discussion? (d) If discussion and narrative co-occur, what sorts of oral narratives do narrators tell in discussions? and (e) If discussion and narrative co-occur, how can we characterize the overlap in terms of interaction? In the frequent conversational narrative discussions, where oral narrative and discussion discourse overlapped, teacher and students used various kinds of oral narrative genres to prime, sustain, ratify, and amplify discussion.
A New Approach to Teaching Veterinary Public Health at the Ohio State University
Authors: Hoet Armando E. , Caswell Robert J. , DeGraves Fred J. , Rajala-Schultz Paivi J. , Gebreyes Wondwossen A. , Saville William J.A. , Wittum Thomas E.
Published: August 2008

Public-health practitioners with expertise in the area of veterinary public health are expected to understand the prevention and control of zoonotic infectious diseases in both human and animal populations. This focus on multiple species is what makes the veterinary public health (VPH) official unique. The development of a new VPH specialization within the existing Master of Public Health (MPH) degree program at the Ohio State University represents a significant new collaboration between the College of Veterinary Medicine and the College of Public Health. The main objective of the VPH specialization is to educate and train professionals to provide them with the skills, knowledge, and resources necessary to protect and improve human health using a One Medicine approach. The program targets a population of students who will likely enter the professional veterinary medicine curriculum but have one year available to enhance their preparatory training in health sciences before beginning the program. A core series of VPH courses was initiated to complement the existing MPH course requirements. The program has been successful in attracting students from the primary target population, but it has also attracted students wanting the MPH as a terminal degree and veterinarians returning to school to expand their career options.
The Cooperative University of Iowa / Iowa State University MPH Program
Authors: Bickett-Weddle Danelle A. , Aquilino Mary L. , Roth James A.
Published: August 2008

Public health is an important component of veterinary medicine. In the last 10 years, there has been growing recognition of the need to increase the number of veterinarians trained in public health. The Center for Food Security and Public Health (CFSPH) at Iowa State University (ISU), College of Veterinary Medicine, received a grant from the Centers for Disease Control and Prevention (CDC) to support veterinarians working at CFSPH while pursuing the Master of Public Health degree. CFSPH and ISU administrators worked with the University of Iowa (UI) College of Public Health to establish three cooperative programs for veterinarians to earn the MPH degree. This article describes how these programs were developed and how they operate.

(1) Between 2002 and 2005, CFSPH used funds provided by the CDC to support 15 veterinarians as they worked for CFSPH and toward the MPH degree. As the program grew, distance-education methods such as the Internet, Polycom videoconferencing, and the Iowa Communications Network (ICN) were incorporated. (2) A concurrent DVM/MPH degree is now offered; students can complete both degrees in four years. As of January 2008, three students have received their DVM and MPH degrees and 16 students are enrolled in the program. (3) In June 2007, the UI and ISU launched a distance MPH program for veterinarians working in private practice, industry, and government. Eight veterinarians are participating in the program, which includes two two-week, in-person summer sessions, with the remainder of the coursework taken at a distance via the Internet.
Public-Health Education at Kansas State University
Authors: Akers Jennifer , Payne Patricia , Ann Holcomb Carol , Rush Bonnie , Renter David , Moro Manuel H. , Freeman Lisa C.
Published: August 2008

What are veterinary medical and public-health professionals doing to remedy the immediate and impending shortages of veterinarians in population health and public practice? This question was addressed at the joint symposium of the Association of American Veterinary Medical Colleges and the Association of Schools of Public Health, held in April 2007. Thinking locally, faculty and students at Kansas State University (KSU) asked similar questions after attending the symposium: What are we doing within the College of Veterinary Medicine to tackle this problem? What can we do better with new collaborators? Both the professional veterinary curriculum and the Master of Public Health (MPH) at KSU provide exceptional opportunities to address these questions. Students are exposed to public health as a possible career choice early in veterinary school, and this exposure is repeated several times in different venues throughout their professional education. Students also have opportunities to pursue interests in population medicine and public health through certificate programs, summer research programs, study abroad, and collaborations with contributing organizations unique to KSU, such as its Food Science Institute, National Agricultural Biosecurity Center, and Biosecurity Research Institute. Moreover, students may take advantage of the interdisciplinary nature of public-health education at KSU, where collaborations with several different colleges and departments within the university have been established. We are pleased to be able to offer these opportunities to our students and hope that our experience may be instructive for the development of similar programs at other institutions, to the eventual benefit of the profession at large.
Linking Veterinary and Human Public-Health Education: Collaborations at the University of Tennessee
Authors: Howell Nancy E. , Hamilton Charles , New John , Lane India , Brace James
Published: August 2008

The increasing demand for veterinarians in public health has created an environment for innovative educational approaches, providing opportunities for veterinary students to gain additional education in public health. At the University of Tennessee, this environment has enabled a collaboration between the College of Veterinary Medicine and the College of Education, Health, and Human Sciences to establish a veterinary concentration in an existing Master of Public Health degree program. The veterinary public-health concentration was approved in 2004. In addition, other courses and initiatives have been developed at the College of Veterinary Medicine, creating stronger collaborations with academic units and public-health professionals.
Enhancing Food-Safety Education through Shared Teaching Resources
Authors: McDonald Jeannette
Published: August 2008

The American public is concerned about food safety, and there is a growing realization that we are ill equipped to handle major food-borne illness outbreaks and bioterrorism. Since veterinary medicine plays an important role in assuring the safety of our nation's food supply, we would like to present to veterinary and public health educators a newly emerging resource for food-safety educational materials. This article describes an integrative collaborative approach for the creation and dissemination of engaging food-safety teaching resources for veterinary faculty. This USDA-funded project, Design to Dissemination: Developing Materials and Repository for Integrative Veterinary Food Safety Education, involves expert teachers in diverse fields and from many veterinary schools.

The purpose of the project is to create materials that teach students food safety from farm to fork, and it offers teachers clinically relevant teaching resources that are difficult to create or locate. The educational materials are being created as smaller “building blocks” of content, commonly referred to as “learning objects” (LOs), focused on individual learning objectives. These learning objects are placed in the Veterinary Food Safety Education Learning Object Repository, where they are catalogued, stored, and kept accessible and where faculty can search, evaluate, and download teaching materials to use in their courses. In this way the learning objects can be more easily shared and reused or repurposed for other courses and applications. With this article we hope to excite faculty in veterinary schools and public-health programs and encourage them to use the repository and participate in piloting the educational materials.