bluuebunny/crossref_metadata_2025 huggingface dataset:
Meteorin promotes the formation of GFAP-positive glia via activation of the Jak-STAT3 pathway
Authors: Lee Hye Shin , Han Jiyeon , Lee Soon-Hee , Park Jeong Ae , Kim Kyu-Won
Published: May 2010

Meteorin is an orphan ligand which has been previously reported to control neuritogenesis and angiogenesis, as well as gliogenesis. However, the precise function of this factor in CNS development and the underlying molecular mechanisms are poorly understood. Here, we demonstrate that meteorin is involved in GFAP-positive glial differentiation through activation of the Jak-STAT3 pathway, by using neurosphere and retinal explant culture systems. During embryonic brain development, meteorin is highly expressed in neural stem and radial glia cells of the ventricular zone and immature neurons outside the ventricular zone but its expression disappears spontaneously as development proceeds except in GFAP-positive astrocytes. In cultured neurospheres, meteorin activates STAT3, and in turn increases the transcriptional activity of GFAP by enhancing the binding of STAT3 to the promoter. By meteorin stimulation, differentiating neurospheres show increased numbers of GFAP-positive cells, but the effect is abrogated by a blockade of the Jak-STAT3 pathway using either a Jak inhibitor or STAT3 siRNA. Furthermore, we expand our findings to the retina, and show that meteorin increases GFAP expression in Müller glia. Together, our results suggest that meteorin promotes GFAP-positive glia formation by mediating the Jak-STAT3 signaling pathway during both cortical stem cell differentiation and retinal glia development.
LRP2 in ependymal cells regulates BMP signaling in the adult neurogenic niche
Authors: Gajera Chandresh R. , Emich Helena , Lioubinski Oleg , Christ Annabel , Beckervordersandforth-Bonk Ruth , Yoshikawa Kazuaki , Bachmann Sebastian , Christensen Erik Ilsø , Götz Magdalena , Kempermann Gerd , Peterson Andrew S. , Willnow Thomas E. , Hammes Annette
Published: May 2010

The microenvironment of growth factors in the subependymal zone (SEZ) of the adult brain provides the instructive milieu for neurogenesis to proceed in this germinal niche. In particular, tight regulation of bone morphogenetic protein (BMP) signaling is essential to balance proliferative and non-proliferative cell fate specification. However, the regulatory pathways that control BMP signaling in the SEZ are still poorly defined. We demonstrate that LRP2, a clearance receptor for BMP4 is specifically expressed in ependymal cells of the lateral ventricles in the adult brain. Intriguingly, expression is restricted to the ependyma that faces the stem cell niche. Expression is not seen in ependyma elsewhere in the lateral ventricles or in the dentate gyrus, the second major neurogenic zone of the adult brain. We further show that lack of LRP2 expression in adult mice results in impaired proliferation of neural precursor cells in the SEZ resulting in decreased numbers of neuroblasts reaching the olfactory bulb. Reduced neurogenesis coincides with increased BMP4 expression and enhanced activation of downstream mediators phospho-SMAD1/5/8 and ID3 in the stem cell niche. Our findings suggest a novel mechanism whereby LRP2-mediated catabolism of BMP4 in the ependyma modulates the microenvironment of the SEZ and enables adult neurogenesis to proceed.
Bre1p-mediated histone H2B ubiquitylation regulates apoptosis in Saccharomyces cerevisiae
Authors: Walter David , Matter Anja , Fahrenkrog Birthe
Published: May 2010

BRE1 encodes an E3 ubiquitin protein ligase that is required for the ubiquitylation of histone H2B at lysine 123 (K123). Ubiquitylation of this histone residue is involved in a variety of cellular processes including gene activation and gene silencing. Abolishing histone H2B ubiquitylation also confers X-ray sensitivity and abrogates checkpoint activation after DNA damage. Here we show that Saccharomyces cerevisiae Bre1p exhibits anti-apoptotic activity in yeast and that this is linked to histone H2B ubiquitylation. We found that enhanced levels of Bre1p protect from hydrogen-peroxide-induced cell death, whereas deletion of BRE1 enhances cell death. Moreover, cells lacking Bre1p show reduced lifespan during chronological ageing, a physiological apoptotic condition in yeast. Importantly, the resistance against apoptosis is conferred by histone H2B ubiquitylation mediated by the E3 ligase activity of Bre1p. Furthermore, we found that the death of Δbre1 cells depends on the yeast caspase Yca1p, because Δbre1 cells exhibit increased caspase activity when compared with wild-type cells, and deletion of YCA1 leads to reduced apoptosis sensitivity of cells lacking Bre1p.
Secretion is required for late events in the cell-fusion pathway of mating yeast
Authors: Grote Eric
Published: May 2010

Secretory vesicles accumulate adjacent to the contact site between the two cells of a yeast mating pair before they fuse, but there is no direct evidence that secretion is required to complete fusion. In this study, temperature-sensitive secretion (sects) mutants were used to investigate the role of secretion in yeast cell fusion. Cell fusion arrested less than 5 minutes after inhibiting secretion. This rapid fusion arrest was not an indirect consequence of reduced mating pheromone signaling, mating-pair assembly or actin polarity. Furthermore, secretion was required to complete cell fusion when it was transiently inhibited by addition and removal of the lipophilic styryl dye, FM4-64. These results indicate that ongoing secretion is required for late events in the cell-fusion pathway, which include plasma-membrane fusion and the completion of cell-wall remodeling, and they demonstrate a just-in-time delivery mechanism for the cell-fusion machinery.
Explaining the Gender Gap in Math Test Scores: The Role of Competition
Authors: Niederle Muriel , Vesterlund Lise
Published: May 2010

The mean and standard deviation in performance on math test scores are only slightly larger for males than for females. Despite minor differences in mean performance, many more boys than girls perform at the right tail of the distribution. This gender gap has been documented for a series of math tests including the AP calculus test, the mathematics SAT, and the quantitative portion of the Graduate Record Exam (GRE). The objective of this paper is not to discuss whether the mathematical skills of males and females differ, be it a result of nurture or nature. Rather we argue that the reported test scores do not necessarily match the gender differences in math skills. We will present results that suggest that the evidence of a large gender gap in mathematics performance at high percentiles in part may be explained by the differential manner in which men and women respond to competitive test-taking environments. The effects in mixed-sex settings range from women failing to perform well in competitions, to women shying away from environments in which they have to compete. We find that the response to competition differs for men and women, and in the examined environment, gender difference in competitive performance does not reflect the difference in noncompetitive performance. We argue that the competitive pressures associated with test taking may result in performances that do not reflect those of less-competitive settings. Of particular concern is that the distortion is likely to vary by gender and that it may cause gender differences in performance to be particularly large in mathematics and for the right tail of the performance distribution. Thus the gender gap in math test scores may exaggerate the math advantage of males over females.
Markets: The Credit Rating Agencies
Authors: White Lawrence J
Published: May 2010

This paper will explore how the financial regulatory structure propelled three credit rating agencies—Moody's, Standard & Poor's (S&P), and Fitch—to the center of the U.S. bond markets—and thereby virtually guaranteed that when these rating agencies did make mistakes, these mistakes would have serious consequences for the financial sector. We begin by looking at some relevant history of the industry, including the series of events that led financial regulators to outsource their judgments to the credit rating agencies (by requiring financial institutions to use the specific bond creditworthiness information that was provided by the major rating agencies) and when the credit rating agencies shifted their business model from “investor pays” to “issuer pays.” We then look at how the credit rating industry evolved and how its interaction with regulatory authorities served as a barrier to entry. We then show how these ingredients combined to contribute to the subprime mortgage debacle and associated financial crisis. Finally, we consider two possible routes for public policy with respect to the credit rating industry: One route would tighten the regulation of the rating agencies, while the other route would reduce the required centrality of the rating agencies and thereby open up the bond information process in way that has not been possible since the 1930s.
The Credibility Revolution in Empirical Economics: How Better Research Design is Taking the Con out of Econometrics
Authors: Angrist Joshua D , Pischke Jörn-Steffen
Published: May 2010

Since Edward Leamer's memorable 1983 paper, “Let's Take the Con out of Econometrics,” empirical microeconomics has experienced a credibility revolution. While Leamer's suggested remedy, sensitivity analysis, has played a role in this, we argue that the primary engine driving improvement has been a focus on the quality of empirical research designs. The advantages of a good research design are perhaps most easily apparent in research using random assignment. We begin with an overview of Leamer's 1983 critique and his proposed remedies. We then turn to the key factors we see contributing to improved empirical work, including the availability of more and better data, along with advances in theoretical econometric understanding, but especially the fact that research design has moved front and center in much of empirical micro. We offer a brief digression into macroeconomics and industrial organization, where progress—by our lights—is less dramatic, although there is work in both fields that we find encouraging. Finally, we discuss the view that the design pendulum has swung too far. Critics of design-driven studies argue that in pursuit of clean and credible research designs, researchers seek good answers instead of good questions. We briefly respond to this concern, which worries us little.
Tantalus on the Road to Asymptopia
Authors: Leamer Edward E
Published: May 2010

My first reaction to “The Credibility Revolution in Empirical Economics,” authored by Joshua D. Angrist and Jörn-Steffen Pischke, was: Wow! This paper makes a stunningly good case for relying on purposefully randomized or accidentally randomized experiments to relieve the doubts that afflict inferences from nonexperimental data. On further reflection, I realized that I may have been overcome with irrational exuberance. Moreover, with this great honor bestowed on my “con” article, I couldn't easily throw this child of mine overboard. As Angrist and Pischke persuasively argue, either purposefully randomized experiments or accidentally randomized “natural” experiments can be extremely helpful, but Angrist and Pischke seem to me to overstate the potential benefits of the approach. I begin with some thoughts about the inevitable limits of randomization, and the need for sensitivity analysis in this area, as in all areas of applied empirical work. I argue that the recent financial catastrophe is a powerful illustration of the fact that extrapolating from natural experiments will inevitably be hazardous. I discuss how the difficulties of applied econometric work cannot be evaded with econometric innovations, offering as examples some under-recognized difficulties with instrumental variables and robust standard errors. I conclude with comments about the shortcomings of an experimentalist paradigm as applied to macroeconomics, and some warnings about the willingness of applied economists to apply push-button methodologies without sufficient hard thought regarding their applicability and shortcomings.
The Other Transformation in Econometric Practice: Robust Tools for Inference
Authors: Stock James H
Published: May 2010

Angrist and Pischke highlight one aspect of the research that has positively transformed econometric practice and teaching. They emphasize the rise of experiments and quasi-experiments as credible sources of identification in microeconometric studies, which they usefully term “design-based research.” But in so doing, they miss an important part of the story: a second research strand aimed at developing tools for inference that are robust to subsidiary modeling assumptions. My first aim in these remarks therefore is to highlight some key developments in this area. I then turn to Angrist and Pischke's call for adopting experiments and quasi-experiments in macroeconometrics; while sympathetic, I suspect the scope for such studies is limited. I conclude with some observations on the current debate about whether experimental methods have gone too far in abandoning economic theory.
An Analysis of the Impact of Passenger Profiling for Transportation Security
Authors: Cavusoglu Huseyin , Koh Byungwan , Raghunathan Srinivasan
Published: May 2010

The proponents of airline passenger profiling claim that profiling will reduce the cost of security, improve the detection of attackers, increase the reliability of signals from screening devices, and reduce the inconvenience to normal passengers. In this paper we show that if the Transportation Security Administration (TSA) manually inspects all those passengers classified as likely attackers and sends others through a screening system, as it did when it deployed the Computer Assisted Passenger Prescreening System (CAPPS), then it is superior to no profiling on all four performance measures if and only if the quality of the profiler vis-à-vis that of the screening system is sufficiently high. If the quality of the screening device is sufficiently high, profiling could be detrimental on all four performance measures. On the other hand, if the TSA deploys two screening devices along with the profiler—each screening device optimally configured for each of the two groups of passengers—then profiling improves the reliability of screening device signals, reduces the inconvenience caused to normal passengers, and improves the social welfare even when quality of the screening device is high. One of the implications of our findings is that the security architecture used by the TSA when it deployed CAPPS could provide a strong support to the arguments by some against the use of profiling; however, if the TSA deploys a two-screening device architecture, it might not only blunt the criticism that profiling is discriminatory but also benefit normal passengers and overall society economically.
Subproblem Approximation in Dantzig-Wolfe Decomposition of Variational Inequality Models with an Application to a Multicommodity Economic Equilibrium Model
Authors: Chung William , Fuller J. David
Published: May 2010

We present a modification to Dantzig-Wolfe decomposition of variational inequality (VI) problems that allows for approximation of the VI mapping in the subproblem. The approximation is parameterized by the most recent master problem solution, and it must satisfy two simple requirements. In an electronic companion (online appendix), we show that the proofs of convergence and other important properties go through with subproblem approximation. The approximation procedure is illustrated by an application to a class of multicommodity economic equilibrium models (MCEEMs): the standard Dantzig-Wolfe decomposition by commodity does not allow the subproblem to be decomposed into separate subproblems for each commodity, but we show two ways to approximate the subproblem's inverse demand function, and both ways allow the subproblem to be broken into separate single-commodity problems. A further approximation is combined with each of the inverse demand approximations; in effect, an approximate supply or demand curve is introduced into each commodity's subproblem for transfers of commodities between different subproblems, thus allowing the subproblems to produce better proposals. An illustration is included for an MCEEM that represents energy markets in Canada.
Capacity Allocation and Scheduling in Supply Chains
Authors: Hall Nicholas G. , Liu Zhixin
Published: May 2010

We consider a multiple product supply chain where a manufacturer receives orders from several distributors. If the orders cannot all be met from available production capacity, then the manufacturer allocates that capacity and a set of resubmittable orders among the distributors. The distributors may share their allocated capacity among themselves before submitting revised orders. Finally, the manufacturer schedules the revised orders to minimize its cost. We consider three practical coordination issues. First, we estimate the benefit to the manufacturer from considering scheduling costs and constraints in making capacity and order allocation decisions. Second, we estimate the additional profit that the distributors achieve when they share their allocated capacity. Third, we estimate the value of coordination between the manufacturer and the distributors. Our work is among the first to consider all three issues simultaneously. We model scheduling costs and constraints within the manufacturer's capacity allocation problem. We model the distributors' capacity sharing problem as a cooperative game that has properties that are unique within cooperative game theory. Finally, we develop optimal algorithms for all the models defined by the three coordination issues. Our exact evaluation of decisions about the appropriate coordination level improves managers' ability to make those decisions.
Directed evolution of enantioselective enzymes: An unceasing catalyst source for organic chemistry
Authors: Reetz Manfred T. , Wu Sheng , Zheng Huabao , Prasad Shreenath
Published: May 2010

Directed evolution has emerged as a powerful method for engineering essentially any catalytic parameter of enzymes for application in synthetic organic chemistry and biotechnology, including thermostability, substrate scope, and enantioselectivity. Enantioselectivity is especially crucial when applying biocatalysts to synthetic organic chemistry. This contribution focuses on recent methodology developments in laboratory evolution of stereoselective enzymes, hydrolases, and monooxygenases serving as the enzymes. Specifically, iterative saturation mutagenesis (ISM) has been developed as an unusually effective method to evolve enhanced or reversed enantioselectivity, broader substrate scope, and/or higher thermostability of enzymes.
A l'coute des meskounates: la parole des possdes dans La femme sans spulture d'Assia Djebar
Authors: Berrada Taeb
Published: May 2010

In La femme sans spulture, Assia Djebar relates the story of a communal obsession shared by Algerian women of her native city: the narration and overdue inscription of Zoulikha's story, a heroine of the Algerian War of Independence who was tortured, killed, and abandoned without
a burial place. This article analyzes this obsession in terms of a desire for memory, an archive fever articulated by the voices of possessed women or meskounates. The women who tell the story of this member of the resistance are inhabited by her spectral voice, a narrative voice without
a locus of enunciation. A voice coming from a different place, from the Other who speaks through them and emerges into the text in monologue form allows the re-inscription of Zoulikha's story in a new discursive space of feminine knowledge. This knowledge inaugurates a postcolonial discourse
within which the desire for memory articulated as archive fever is a spectral intruder, a space beyond the text confined within the text that transgresses the official discourse on the Algerian War of Independence.
L'onomastique comme potique de la (d) construction identitaire dans Tels des astres teints de Lonora Miano
Authors: Etoke Nathalie
Published: May 2010

Who am I is a question often asked in African, African American and Afro-Caribbean literatures. Lonora Miano answers this question of identity crisis in Tels des astres teints by exploring the intricacies of naming and identity of Diasporic Sub-Saharan Africans within the French
space. Naming becomes a performative act, which defines the script of existence. The onomastics at work in Tels des astres teints operates as a poetic of identity (de) construction transforming the dichotomization of collective history and personal history into a transcendental mode
of reasoning that attemps to negotiate historical tragedy and breakages of the self. This study offers an approach of self-knowing through naming. The act of naming gives birth to a concrete and abstract reality that operates from a psychological fracture. A productive tension dwells within
this fracture that it is necessary to understand. Structuring her story through free adaptation of jazz themes, Miano displays a dissonant and resilient narrative polyphony through which identity belongs to the realm of becoming.
The “hospital central laboratory”: automation, integration and clinical usefulness
Authors: Zaninotto Martina , Plebani Mario
Published: May 2010

Recent technological developments in laboratory medicine have led to a major challenge, maintaining a close connection between the search of efficiency through automation and consolidation and the assurance of effectiveness. The adoption of systems that automate most of the manual tasks characterizing routine activities has significantly improved the quality of laboratory performance; total laboratory automation being the paradigm of the idea that “human-less” robotic laboratories may allow for better operation and insuring less human errors. Furthermore, even if ongoing technological developments have considerably improved the productivity of clinical laboratories as well as reducing the turnaround time of the entire process, the value of qualified personnel remains a significant issue. Recent evidence confirms that automation allows clinical laboratories to improve analytical performances only if trained staff operate in accordance with well-defined standard operative procedures, thus assuring continuous monitoring of the analytical quality. In addition, laboratory automation may improve the appropriateness of test requests through the use of algorithms and reflex testing. This should allow the adoption of clinical and biochemical guidelines. In conclusion, in laboratory medicine, technology represents a tool for improving clinical effectiveness and patient outcomes, but it has to be managed by qualified laboratory professionals.

Clin Chem Lab Med 2010;48:911–7.
Nicotinamide Adenine Dinucleotide-Dependent Binding of the Neuronal Ca2+Sensor Protein GCAP2 to Photoreceptor Synaptic Ribbons
Authors: Venkatesan Jagadeesh Kumar , Natarajan Sivaraman , Schwarz Karin , Mayer Sabine I. , Alpadi Kannan , Magupalli Venkat Giri , Sung Ching-Hwa , Schmitz Frank
Published: May 2010

Guanylate cyclase activating protein 2 (GCAP2) is a recoverin-like Ca2+-sensor protein known to modulate guanylate cyclase activity in photoreceptor outer segments. GCAP2 is also present in photoreceptor ribbon synapses where its function is unknown. Synaptic ribbons are active zone-associated presynaptic structures in the tonically active photoreceptor ribbon synapses and contain RIBEYE as a unique and major protein component. In the present study, we demonstrate by various independent approaches that GCAP2 specifically interacts with RIBEYE in photoreceptor synapses. We show that the flexible hinge 2 linker region of RIBEYE(B) domain that connects the nicotinamide adenine dinucleotide (NADH)-binding subdomain with the substrate-binding subdomain (SBD) binds to the C terminus of GCAP2. We demonstrate that the RIBEYE–GCAP2 interaction is induced by the binding of NADH to RIBEYE. RIBEYE–GCAP2 interaction is modulated by the SBD. GCAP2 is strongly expressed in synaptic terminals of light-adapted photoreceptors where GCAP2 is found close to synaptic ribbons as judged by confocal microscopy and proximity ligation assays. Virus-mediated overexpression of GCAP2 in photoreceptor synaptic terminals leads to a reduction in the number of synaptic ribbons. Therefore, GCAP2 is a prime candidate for mediating Ca2+-dependent dynamic changes of synaptic ribbons in photoreceptor synapses.
Identification of Erbin Interlinking MuSK and ErbB2 and Its Impact on Acetylcholine Receptor Aggregation at the Neuromuscular Junction
Authors: Simeone Luca , Straubinger Marion , Khan Muhammad Amir , Nalleweg Nancy , Cheusova Tatiana , Hashemolhosseini Said
Published: May 2010

Erbin, a binding partner of ErbB2, was identified as the first member of the LAP family of proteins. Erbin was shown at postsynaptic membranes of the neuromuscular junction (NMJ) or in cultured C2C12 myotubes (1) to be concentrated, (2) to regulate the Ras–Raf–Mek pathway, and (3) to inhibit TGF-β signaling. In the CNS, Erbin interacts with PSD-95. Furthermore, agrin–MuSK signaling initiates formation of AChR aggregates at the postsynaptic membrane. In search of proteins interacting with MuSK, we identified Erbin as a MuSK binding protein. We verified the interaction of MuSK with Erbin, or both concomitantly with ErbB2 by coimmunoprecipitation, and we mapped the interacting epitopes between Erbin and MuSK. We demonstrated elevated mRNA levels of Erbin at synaptic nuclei and colocalized Erbin and MuSK at postsynaptic membranes. We identified several Erbin isoforms at the NMJ, all of which contained the MuSK binding domain. By knocking down Erbin, we observed agrin-dependent AChR aggregates on murine primary skeletal myotubes and C2C12 cells, and in the absence of agrin, microclusters, both of significantly lower density. Complementary, AChR-ε-reporter expression was reduced in myotubes overexpressing Erbin. We show that myotubes also express other LAP protein family members, namely Scribble and Lano, and that both affect physical dimensions of agrin-dependent AChR aggregates and density of microclusters formed in the absence of agrin. Moreover, MuSK–Erbin–ErbB2 signaling influences TGF-β signaling. Our data define the requirement of Erbin on the cross talk between agrin and neuregulin signaling pathways at the NMJ.
Evolution & Phylogenetic Analysis: Classroom Activities for Investigating Molecular & Morphological Concepts
Authors: Franklin Wilfred A.
Published: May 2010

In a flexible multisession laboratory, students investigate concepts of phylogenetic analysis at both the molecular and the morphological level. Students finish by conducting their own analysis on a collection of skeletons representing the major phyla of vertebrates, a collection of primate skulls, or a collection of hominid skulls.
Experience Millions of Years
Authors: Flammer Larry
Published: May 2010

Here's a relatively concrete activity to teach the large numbers representing evolutionary deep time.
Charles Darwin's Botanical Investigations
Authors: Harley Suzanne M.
Published: May 2010

Charles Darwin's botanical studies provide a way to expose students to his work that followed the publication of On the Origin of Species. We can use stories from his plant investigations to illustrate key concepts in the life sciences and model how questions are asked and answered in science.
The Ecology of Death: Forensic Entomology as a Teaching Tool
Authors: McNeil James
Published: May 2010

Describing the progression of insects that arrive at a cadaver can be a useful and exciting tool for teaching students about complex concepts such as ecological succession.
A Skeleton Tells Its Own Story: Forensic Analyses of Skeletal Elements for the Science Classroom Laboratory
Authors: Naples Virginia L. , Breed David , Miller Jon S.
Published: May 2010

The techniques of forensic anthropology and pathology can provide new information to increase student interest in studying the structural details of the human skeleton. We present a simplified methodology for assessing skeletal ethnicity, sex, age, and stature. An inexpensive method has been devised for constructing an osteometric board to allow students to measure long bones accurately. The effects of aging and the influence of lifestyle alterations on skeletal elements are presented along with the prediction of their effects on the living individual. This laboratory is intended to acquaint students with the process of collecting and analyzing data, interpreting scientific results, and assessing the accuracy of their conclusions. Gathering and analyzing their own data sets gives students a better understanding of the scientific method and an increased ability to translate this understanding to other scientific disciplines.
Making the Most of theDaphniaHeart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine
Authors: Corotto Frank , Ceballos Darrel , Lee Adam , Vinson Lindsey
Published: May 2010

Students commonly test the effects of chemical agents on the heart rate of the crustacean Daphnia magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in Daphnia. Ethanol at 5% and 10% (v/v) reduced mean heart rate to ∼50% and ∼20% of its initial value, respectively. Recovery was rapid after removing 5% ethanol, but recovery from 10% ethanol took 20—30 minutes. Nicotine at 100 μM reversibly increased mean heart rate by ∼20%. Higher concentrations produced varied and sometimes irreversible effects. Caffeine at 0.1%, 0.5%, and 2% (w/v) had no convincing effect on heart rate. Of the three agents tested, nicotine's peculiar effects make it the least useful in an educational setting. Caffeine could be used to emphasize the need for blind observers because it does not increase heart rate in Daphnia. If students find that it does, their bias is revealed. Ethanol produces unambiguous effects at 5% and 10%. Heart rates recover quickly after removing 5% ethanol, which allows students to explore reversibility as an alternative to having a separate control group.
Using an Active-Learning Approach to Teach Epigenetics
Authors: Colóón-Berlingeri Migdalisel
Published: May 2010

Epigenetics involves heritable changes in gene expression that do not involve alterations in the DNA sequence. I developed an active-learning approach to convey this topic to students in a college genetics course. I posted a brief summary of the topic before class to stimulate exchange in cooperative groups. During class, we discussed the genotypic and phenotypic differences between monozygotic twins and the role of epigenetic mechanisms in these differences. I also presented the molecular mechanisms that lead to these epigenetic changes as well as techniques used to study them. Students were particularly interested in pondering the relationships between environmental interactions, epigenetic changes, and phenotypic consequences, including human behavior.
Genetics in the 21st Century: The Benefits & Challenges of Incorporating a Project-Based Genetics Unit in Biology Classrooms
Authors: Alozie Nonye , Eklund Jennifer , Rogat Aaron , Krajcik Joseph
Published: May 2010

How can science instruction help students and teachers engage in relevant genetics content that stimulates learning and heightens curiosity? Project-based science can enhance learning and thinking in science classrooms. We describe how we use project-based science features as a framework for a genetics unit, discuss some of the challenges encountered, and provide suggestions for enactment. This serves as an example of how project-based approaches can be integrated into high school science classrooms.
Using Harry Potter to Introduce Students to DNA Fingerprinting & Forensic Science
Authors: Palmer Laura K.
Published: May 2010

This lesson uses characters from the Harry Potter series of novels as a ‘‘hook’’ to stimulate students' interest in introductory forensic science. Students are guided through RFLP (restriction fragment length polymorphism) analysis using inexpensive materials and asked to interpret data from a mock crime scene. Importantly, the lesson provides an opportunity to discuss limitations of using DNA fingerprinting for forensic purposes and addresses a common misconception that the sophisticated science involved in crime-scene analysis is infallible.
A Photosynthesis Rap Song
Authors: English Rita C.
Published: May 2010

I wrote a rap song to explain the process of photosynthesis to my students.
Sectioning Clay Models Makes Anatomy & Development Tangible
Authors: Howell Carina Endres , Howell James Endres
Published: May 2010

Clay models have proved to be useful teaching aids for many topics in biology that depend on three-dimensional reasoning. Students studying embryonic development struggle to mentally reconstruct the three-dimensional structure of embryos and larvae by observing prepared slides of cross-sectional slices. Students who build clay models of embryos and slice them into cross sections, however, have a much easier time interpreting the slices of real embryos and gain a deeper understanding of development in three dimensions.
Teaching Flower Structure & Floral Formulae — A Mix of the Real & Virtual Worlds
Authors: Burrows Geoff
Published: May 2010

The study of flower structure is essential in plant identification and in understanding sexual reproduction in plants, pollination syndromes, plant breeding, and fruit structure. Thus, study of flower structure and construction of floral formulae are standard parts of first-year university botany and biology courses. These activities involve developing a complex set of skills, and it is useful for students to review this material after practical sessions. The Virtual Floral Formula Web site provides students with a unique resource for practicing their floral structure interpretation skills. The site provides detailed dissection photographs of the flowers of 12 species, and floral formulae are progressively assembled via drop-down menus. When students are satisfied with their answers, they submit them, and any discrepancies from the ‘official’ formula are highlighted. Students appreciate the interactivity of the application, the feedback they receive on any inaccuracies in their formulae, and the ability to make progressive improvements in their skills.
Introducing Students to Darwin via the Voyage of HMS Beagle
Authors: Swab Janice C.
Published: May 2010

I use the diary that Darwin wrote during the voyage of HMS Beagle and recent images of a few of the places he visited to illustrate some comparisons between Darwin's world and ours. For today's students, increasingly committed to environmental issues, this may be an especially promising way to introduce Darwin.
The Biodiversity Community Action Project: An STS Investigation
Authors: Aidin Amirshokoohi , Mahsa Kazempour
Published: May 2010

The Biodiversity Community Action Project is a stimulating and vigorous project that allows students to gain an in-depth understanding of the interconnection between organisms and their environments as well as the connection of science to their lives and society. It addresses key content standards in the National Science Education Standards and integrates research, writing, and communication.
A Provably Necessary Symbiosis
Authors: Robert Hochberg , Kathleen Gabric
Published: May 2010

The “new biology” of the 21st century is increasingly dependent on mathematics, and preparing high school students to have both strong science and math skills has created major challenges for both disciplines. Researchers and educators in biology and mathematics have been working long hours on a project to create high school teaching modules suitable for both biology and mathematics classrooms, as well as classes held jointly, to help supply teachers with materials that can be used in classrooms attempting to overcome the disciplinary boundaries that often separate them. Biology topics such as evolution, ecology, bioinformatics, and epidemiology are interwoven with a variety of mathematical topics, including algebraic equations, multiplying matrices, algorithms, dynamic programming, probability, and graphing. These modules will be free to educators for a few years. We give an overview of the modules and describe how to obtain them.
Laboratories, Museums, and the Comparative Perspective: Alan A. Boyden's Quest for Objectivity in Serological Taxonomy, 1924–1962
Authors: Strasser Bruno J.
Published: May 2010

The rise of experimentation and the decline of natural history constitute the historiographic backbone to most narratives about the history of the life sciences in the twentieth century. As I argue here, however, natural history practices, such as the collection and comparison of data from numerous species, and experimental practices have actually converged throughout the century, giving rise to a new hybrid research culture which is essential to the contemporary life sciences. Looking at some examples of researchers who studied experimentally the relationships between organisms offers a unique window into how the norms, values, and practices of natural history entered the laboratory and, conversely, how the norms, values, and practices of experimentation transformed natural history. This paper concentrates on a largely overlooked episode in the history of the life sciences: the development of Alan A. Boyden's serological taxonomy. In the United States, from the late 1920s to the early 1960s, he was the most prominent advocate of this experimental approach in natural history. His quest for an objective method to understand the relationships among species, his creation of a serological museum where he could apply his comparative perspective, and his continued negotiations between natural historical and experimental traditions, illustrate the rise of a new hybrid research culture in the twentieth century. It also helps us solve a historiographic puzzle, namely how biological diversity become so central in the experimental life sciences, i.e., in a tradition which we generally understand as having focused on a few model organisms, and which relegated the study of biodiversity to naturalists and their museums.
Factors predicting relapse of nonfunctioning pituitary macroadenomas after neurosurgery: a study of 142 patients
Authors: Brochier Sophie , Galland Françoise , Kujas Michèle , Parker Fabrice , Gaillard Stephan , Raftopoulos Christian , Young Jacques , Alexopoulou Orsalia , Maiter Dominique , Chanson Philippe
Published: May 2010

Context

Adequate postoperative management of nonfunctioning pituitary macroadenomas (NFMAs) remains a challenge for the clinician.

Objective

To identify predictive factors of NFMA relapse after initial surgery.

Patients and methods

This retrospective study included 142 patients operated for an NFMA in two academic centers (CHU Bicêtre in France and UCL St Luc in Belgium). The rate of tumor relapse, defined as recurrence after total surgical resection or regrowth of a surgical remnant, as well as predictive factors was analyzed.

Results

During a mean follow-up of 6.9 years, 10 out of 42 patients (24%) who had complete macroscopic resection of their tumor had recurrence, and 47 out of 100 patients (47%) with a surgical remnant experienced regrowth. The overall relapse rates were 25, 43, and 61% at 5, 10, and 15 years respectively. Invasion of the cavernous sinus, absence of immediate radiotherapy after the first neurosurgery, and immunohistochemical features of the tumor (mainly positive immunostaining for several hormones or for hormones other than gonadotropins) were independent risk factors for tumor relapse. Incomplete excision was only associated with relapse when invasion was withdrawn from the analysis, suggesting that these two factors are closely linked.

Conclusion

NFMAs frequently recur/regrow after initial surgery, particularly when tumor is invasive, precluding complete removal. Immunohistochemical features such as positive immunostaining for several hormones or for hormones other than gonadotropins could help to predict undesirable outcomes.
Partial genome analysis of Siberian sturgeon alloherpesvirus suggests its close relation to AciHV-2 — Short communication
Authors: Doszpoly Andor , Shchelkunov Igor
Published: May 2010

Partial genome sequence of a herpes-like virus, isolated from Siberian sturgeon (
Acipenser baeri
), was determined and subjected to phylogenetic analysis. The virus (SbSHV) has been shown to be the causative agent of an acute disease with high mortality in farmed juvenile sturgeons in Russia. Two fragments (of 7000 and 300 base pairs in length) encompassing 3 complete and 3 partial ORFs were amplified by PCR. Sturgeon herpesvirus strains, classified into species
Acipenserid herpesvirus 2
(AciHV-2), have been isolated and partially sequenced from several regions (California, Idaho, Oregon and Canada) of North America from white (
A. transmontanus)
and shortnose sturgeons (
A. brevirostrum
). The sequence of the SbSHV strain shared highest identity with that of the Canadian strain originating from shortnose sturgeon. The phylogenetic analysis also confirmed that SbSHV is closely related to AciHV-2 and could also be classified into this virus species. This is the first report on the occurrence of AciHV-2 in Europe. Previously, only another virus species, AciHV-1 has been detected in farmed white sturgeons in Italy. The size and position of ORFs in the examined gene block confirmed that this genomic region is highly conserved in members of the genus
Ictalurivirus
.
Therapeutic efficacy of botulinum toxin in the treatment of urinary incontinence in female dogs
Authors: Lew Sylwia , Majewski Mariusz , Radziszewski Piotr , Kuleta Zygmunt
Published: May 2010

Urinary incontinence in animals poses a growing therapeutic problem. Satisfactory results in the treatment of incontinence are not reported despite the wide availability of pharmaceuticals addressing the problem. The growing number of side effects and the need for sustained pharmacotherapy have prompted a search for new treatment methods. The experiment described in this study was performed on 11 bitches with clinical symptoms of urinary incontinence. The dogs underwent cystoscopy during which botulinum toxin solution was injected into the wall of the urinary bladder (50–100 botulinum toxin units were given per animal in 10 injections), causing changes in its innervation. Positive therapeutic effects lasting for 5 months in average were noted in 70% of the treated animals.
Effect of delayed feed access on production and blood parameters of layer-type chicks
Authors: Gaglo-Disse Adjovi , Tona Kokou , Aliou Sakibou , Debonne Marian , Aklikokou Kodjo , Gbeassor Messanvi , Decuypere Eddy
Published: May 2010

A total of 684 Hisex Brown day-old chicks were studied. The chicks were randomly assigned into three groups as follows: (1) chicks with immediate feed access; (2) chicks with 48 h delay in feed access, and (3) chicks with 72 h delay in feed access. For each group, chicks were assigned into 4 replications of 57 birds each. Prior to feed access, the chicks were weighed. Samples of chicks were used to weigh yolk sac at 1, 3 and 7 days and to collect blood at 1, 3, 7, 14 and 56 days. Also, reared chicks were weighed weekly. The results indicated that chick weights decreased during the holding period. Yolk sac utilisation was similar between groups, while morbidity and mortality increased linearly with the duration of delay in feed access. At 56 days, chicks having delayed access to feed were lighter than those without delay in feed access. Serum concentration of glucose up to 14 days and of total protein and triglycerides until 56 days decreased with the increasing duration of delay in feed access. It can be concluded that delayed feed access is detrimental to the juvenile performance of layer-type chicks and has a negative age-related effect on the serum concentrations of glucose, triglycerides and total protein.
Partial pressure of carbon dioxide in the venous blood of young birds as a predictor of ascites susceptibility in broiler chickens
Authors: Hassanzadeh Mohammad , Maddadi Mohammad , Mirzaie Sarra , Assasie Keramat , Moayyedian Hamid
Published: May 2010

In order to investigate the relationship between carbon dioxide tensions in the venous blood of young chickens and ascites susceptibility, one hundred dayold chickens from two pure broiler breeder lines differing in susceptibility to ascites syndrome were obtained and reared at low environmental temperature. Weekly, blood samples were taken for the determination of blood gas parameters and plasma thyroid hormone levels. Dead birds were examined for lesions of ascites daily and all survived birds were autopsied at the end of the trials. In cold conditioning, the cumulative incidence of right ventricular hypertrophy (RVH) and ascites was 78% (39/50) in fast-growing (line A) and 50% (25/50) in slow-growing (line B) chickens, confirming that line A chickens had higher susceptibility to ascites than line B chickens. At 12 days of age, the mean pCO
2
tension was significantly (P < 0.01) higher in the venous blood of line A than line B chickens. During the experiment, the majority of line A and line B chickens showing RVH and ascites exhibited pCO
2
tensions equal to, or exceeding 50 mmHg at 12 days of age. Additionally, fast-growing chickens showed significantly lower plasma T3 and T4 concentrations than slow-growing chickens. In conclusion, our data indicate that carbon dioxide pressure in the venous blood of early postnatal broiler chickens could be used as a valuable predictor in the selection of birds susceptible to pulmonary hypertension and ascites. The function of thyroid hormones should also be taken into consideration in further selection procedures for meat-type chickens.
Potential infectivity of Anaplasma phagocytophilum strains in Ixodes ricinus ticks from Serbia
Authors: Tomanović Snežana , Radulović Željko , Masuzawa Toshiyuki , Milutinović Marija , Stanisavljević Ljubiša
Published: May 2010

Anaplasma phagocytophilum
strains from different geographical regions are characterised by diverse potential infectivity for humans and domesticated animals. We investigated the potential pathogenicity of
A. phagocytophilum
strains in
Ixodes ricinus
ticks from 11 geographically different localities in Serbia. Sequences obtained in this study showed a high variability of
p44
paralogues. Some of them, however, formed groups with similarities greater than 86% (‘similarity groups’). Previous studies showed that ‘similarity groups’ were nearly always country specific. Our results correlated with this observation, and we also observed significant clustering of paralogues according to vector and reservoir origin of
A. phagocytophilum
strains. According to the high genetic similarity of sequences isolated from ticks collected in four localities, namely Avala, Batrovci, Hajdučka česma and Ljubovija, with paralogues with proven pathogenicity isolated from human granulocytic anaplasmosis (HGA) patients and
A. phagocytophilum
infected sheep, we could assume that strains with potential infectivity for humans and domestic animals were present in Serbia.