bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reconstructing eukaryotic NAD metabolism
Authors: Rongvaux Anthony , Andris Fabienne , Van Gool Frédéric , Leo Oberdan 
Published: June 2003

AbstractIn addition to its well‐known role as a coenzyme in oxidation–reduction reactions, the distinct role of NAD as a precursor for molecules involved in cell regulation has been clearly established. The involvement of NAD in these regulatory processes is based on its ability to function as a donor of ADP‐ribose; NAD synthesis is therefore required to avoid depletion of the intracellular pool. The rising interest in the biosynthetic routes leading to NAD formation and the highly conserved nature of the enzymes involved prompted us to reconstruct the NAD biosynthetic routes operating in distinct eukaryotic organisms. The evidence obtained from biochemical and computational analysis provides a good example of how complex metabolic pathways may evolve. In particular, it is proposed that the development of several NAD biosynthetic routes during evolution has led to partial functional redundancy, allowing a given pathway to freely acquire novel functions unrelated to NAD biosynthesis. BioEssays 25:683–690, 2003. © 2003 Wiley Periodicals, Inc.
The role of class I HLH genes in neural development—have they been overlooked?
Authors: Ik Tsen Heng Julian , Tan Seong‐Seng 
Published: June 2003

AbstractHelix–loop–helix (HLH) genes encode for transcription factors affecting a whole variety of developmental programs, including neurogenesis. At least seven functional classes (denoted I to VII) of HLH genes exist,1 with subclass members exhibiting homo‐ and heterodimerisation for proper DNA binding and transcriptional regulation of downstream target genes. In the developing nervous system, members of class II, V and VI have been most extensively studied concerning their roles in neural programming. In contrast, the function of class I proteins (such as E12 and E47) is poorly defined and the orthodox view relegates them to general dimerisation duties that are necessary for the activity of the other classes. However, closer scrutiny of the spatiotemporal expression patterns of class I factors, combined with recent biochemical evidence, would suggest that class I proteins possess specific functions during early neural differentiation. This essay supports this possibility, in addition to putting forward the hypothesis that, outside their general dimerisation activity, class I genes have independent roles in regulating neurogenesis. BioEssays 25:709–716, 2003. © 2003 Wiley Periodicals, Inc.
The pleiotropic functions of the Y‐box‐binding protein, YB‐1
Authors: Kohno Kimitoshi , Izumi Hiroto , Uchiumi Takeshi , Ashizuka Megumi , Kuwano Michihiko 
Published: June 2003

AbstractThe Y‐box‐binding protein (YB‐1) represents the most evolutionary conserved nucleic‐acid‐binding protein currently known. YB‐1 is a member of the cold‐shock domain (CSD) protein superfamily. It performs a wide variety of cellular functions, including transcriptional regulation, translational regulation, DNA repair, drug resistance and stress responses to extracellular signals. As a result, YB‐1 expression is closely associated with cell proliferation. In this review, we will begin by briefly describing the characteristics of YB‐1 and will then summarize the pleiotropic functions brought about via DNA–RNA transaction and protein–protein interactions. In addition, we will discuss the diverse range of potential physiological and pathological functions of YB‐1. BioEssays 25:691–698, 2003. © 2003 Wiley Periodicals, Inc.
The story of cell fusion: Big lessons from little worms
Authors: Shemer Gidi , Podbilewicz Benjamin 
Published: June 2003

AbstractThe ability of two or more cells to unite to form a new syncytial cell has been utilized in metazoans throughout evolution to form many complex organs, such as muscles, bones and placentae. This requires migration, recognition and adhesion between cells together with fusion of their plasma membranes and rearrangement of their cytoplasmic contents. Until recently, understanding of the mechanisms of cell fusion was restricted to fusion between enveloped viruses and their target cells. The identification of new factors that take part in developmental cell fusion in C. elegans opens the way to understanding how cells fuse and what the functions of this process are. In this review, we describe current knowledge on the mechanisms and putative roles of developmental cell fusion in C. elegans and how cell fusion is regulated, together with other intercellular processes to promote organogenesis. BioEssays 25:672–682, 2003. © 2003 Wiley Periodicals, Inc.
Influenza type A in humans, mammals and birds: Determinants of virus virulence, host‐range and interspecies transmission
Authors: Baigent Susan J. , McCauley John W. 
Published: June 2003

AbstractThe virulence of a virus is determined by its ability to adversely affect the host cell, host organism or population of host organisms. Influenza A viruses have been responsible for four pandemics of severe human respiratory disease this century. Avian species harbour a large reservoir of influenza virus strains, which can contribute genes to potential new pandemic human strains. The fundamental importance of understanding the role of each of these genes in determining virulence in birds and humans was dramatically emphasised by the recent direct transmission of avian influenza A viruses to humans, causing fatal infection but not community spread. An understanding of the factors involved in transmission between avian and mammalian species should assist in the development of better surveillance strategies for early recognition of influenza A virus strains having human pandemic potential, and possibly in the design of anti‐viral strategies. BioEssays 25:657–671, 2003. © 2003 Wiley Periodicals, Inc.
Genes, neurons and codes: Remarks on biological communication
Authors: Kerszberg Michel 
Published: June 2003

AbstractI examine critically the application of information‐theoretic ideas to biological communication during embryonic development and in the functioning central nervous system (CNS). I show that intercellular communication relies mostly on simple signals whose role is to effect a selection among predetermined cellular states. Hence, a crucial role is played by cellular memory, which stabilizes such states. Memory in cells is partly located in the nuclear DNA; no less important however is (phenotypic) memory lying in the cell's organelles and compartments. Because of combinatorial effects in gene expression patterns, cell memory is an enormously powerful mechanism, which also underlies plasticity, and thus constitutes the factor unifying genetic determination, plasticity and learning. Communication in the CNS is analyzed in some detail: here, cellular memory is embodied in anatomy (i.e., cell shape) and neurochemistry. These are the major, relatively “static” factors affecting the routing of neural impulses in the adult CNS. In addition, however, faster channeling is also required: action potentials must be directed to their targets along a few of exponentially many paths, and this dynamic routing is crucial for proper operation. I suggest that collective oscillatory modes may play a role in solving this addressing problem, in the same way that the clock signal gates the operation of man‐made computers. BioEssays 25:699–708, 2003. © 2003 Wiley Periodicals, Inc.
Epigenomic replication: Linking epigenetics to DNA replication
Authors: McNairn Adrian J. , Gilbert David M. 
Published: June 2003

AbstractThe information contained within the linear sequence of bases (the genome) must be faithfully replicated in each cell cycle, with a balance of constancy and variation taking place over the course of evolution. Recently, it has become clear that additional information important for genetic regulation is contained within the chromatin proteins associated with DNA (the epigenome). Epigenetic information also must be faithfully duplicated in each cell cycle, with a balance of constancy and variation taking place during the course of development to achieve differentiation while maintaining identity within cell lineages. Both the genome and the epigenome are synthesized at the replication fork, so the events occurring during S‐phase provide a critical window of opportunity for eliciting change or maintaining existing genetic states. Cells discriminate between different states of chromatin through the activities of proteins that selectively modify the structure of chromatin. Several recent studies report the localization of certain chromatin modifying proteins to replication forks at specific times during S‐phase. Since transcriptionally active and inactive chromosome domains generally replicate at different times during S‐phase, this spatiotemporal regulation of chromatin assembly proteins may be an integral part of epigenetic inheritance. BioEssays 25:647–656, 2003. © 2003 Wiley Periodicals, Inc.
Pathways of intracellular communication: Tetrapyrroles and plastid‐to‐nucleus signaling
Authors: Rodermel Steve , Park Sungsoon 
Published: June 2003

AbstractRetrograde plastid‐to‐nucleus signaling plays a central role in coordinating nuclear and plastid gene expression. The gun (genomes uncoupled) mutants of Arabidopsis have been used to demonstrate that Mg‐protoporphyrin (Mg‐Proto) acts as a plastid signal to repress the transcription of nuclear photosynthesis genes.1 It is unclear how Mg‐Proto triggers repression, but several components of this pathway have been recently identified. These include the products of GUN4 and GUN5. GUN5 is the ChlH subunit of Mg‐chelatase, which produces Mg‐Proto, and GUN4 is a regulator of ChlH activity.2 GUN4 might also play a role in photoprotection and in the trafficking of Mg‐Proto. BioEssays 25:631–636, 2003. © 2003 Wiley Periodicals, Inc.
Checkpoint signaling: Epigenetic events sound the DNA strand‐breaks alarm to the ATM protein kinase
Authors: Abraham Robert T. 
Published: June 2003

AbstractThe ATM protein kinase is centrally involved in the cellular response to ionizing radiation (IR) and other DNA double‐strand‐break‐inducing insults. Although it has been well established that IR exposure activates the ATM kinase domain, the actual mechanism by which ATM responds to damaged DNA has remained enigmatic. Now, a landmark paper provides strong evidence that DNA‐strand breaks trigger widespread activation of ATM through changes in chromatin structure.1 This review discusses a checkpoint activation model in which chromatin perturbations lead to the conversion of inactive ATM domains to phosphorylated, active ATM monomers. The new findings underscore the critical importance of epigenetic events in genome function and surveillance in mammalian cells. BioEssays 25:627–630, 2003. © 2003 Wiley Periodicals, Inc.
Die Eroberung des Luftraumes: Wie die Tiere fliegen lernten
Authors: Rüppell Georg 
Published: June 2003

AbstractDie Eroberung des Luftraumes gelang viermal: Insekten, Flugsauriern, Vögeln und Fledermäusen. Warum sind Insekten und Vögel dabei am erfolgreichsten geworden? Auch die Entstehung des Fluges interessiert heute besonders, denn diese Leistung ist von großer Bedeutung für das Verständnis der Evolution. Während viele Ergebnisse vor allem auf paläontologischem Material fußen, wird hier von funktionalen und Anpassungsaspekten ausgegangen. Das kann zur Klärung offener Fragen beitragen, da Fossilien der wirklichen Flugpioniere kaum vorhanden sind.
Das Perm: Farnwälder, Glutwolken und Salzwüsten
Authors: Rößler Ronny 
Published: June 2003

AbstractIm Perm gab es so umwälzende geo‐ und biologische Veränderungen auf der Erde wie nie zuvor. Der Superkontinent Pangäa formierte sich im Zuge der Kollision von Nord‐ und Süderde, intensiver Vulkanismus gestaltete des Antlitz unseres Planeten und sorgte gleichzeitig für die Konservierung und Überlieferung eindrucksvoller Fossilien. Diese gestatten die Rekonstruktion komplexer Nahrungsketten und ‐netze — eine Folge der Erschließung unterschiedlichster Lebensräume. Die Nacktsamer wurden zur dominierenden Pflanzengruppe, erste säugetierähnliche Reptilien traten auf. Die äquatorialen Moorwälder des Karbons wurden abgelöst durch kleinräumige, aber an Vielfalt kaum zu übertreffende Lebensräume. Im marinen Bereich sehen wir in Europa die buchtenreiche Küste des zechsteinzeitlichen Binnenmeeres, dem wir mit Kupferschiefer und Evaporiten wichtige Rohstoffe verdanken. Das große Massensterben sorgte am Ende des Perms für eine explosive Radiation neuer Formen.
SARS: Weltreise eines neuen Virus
Authors: Drosten Christian 
Published: June 2003

AbstractDer Erreger der lebensgefährlichen Lungenkrankheit SARS wird die Forschung noch lange beschäftigen: Das Virus stammt aus einer völlig neuen Gruppe von Coronaviren, von der es vermutlich noch weitere Vertreter gibt. Und: Das Virus könnte sich bei seiner derzeitigen globalen Ausbreitung in neue Wirtstiere zurückziehen, aus denen es dann möglicherweise nochmals ausbricht.
Weltreisende mit gutem Gedächtnis
Authors: Irsch Wilhelm 
Published: June 2003

AbstractVon den heute lebenden etwa 10.000 Vogelarten sind über die Hälfte zumindest teilweise Zugvögel. Schätzungsweise 50 Milliarden Vögel ziehen weltweit jedes Jahr von den Winterquartieren in die Brutgebiete und wieder zurück. Diese Wanderungen erfordern nicht nur ein ausgezeichnetes Orientierungssystem, sondern auch ein gutes Erinnerungsvermögen, wie Erkenntnisse der Max‐Planck‐Forschungsstelle für Ornithologie in Andechs belegen.
Biokontrolle gegen eingewanderte Pflanzen und Tiere
Authors: Brennicke Axel 
Published: June 2003

AbstractIn Australien sind Kaninchen nicht putzig und süß, sondern ein echtes Problem. In den USA sind es die Nutria, in Kassel die Waschbären: eingewanderte Spezies, die heimische Arten verdrängen und sich ungeniert ausbreiten. Ausführliche Studien beweisen jetzt, dass ein Mangel an Feinden die biologischen Invasoren so stark macht. In einer neuen Umgebung werden die Einwanderer deutlich weniger von Krankheitserregern befallen als in ihrem Ursprungsland.
Larven der Tiefsee
Authors: Wendler Silke 
Published: June 2003

AbstractGestielte Seelilien sind besonders urtümliche Vertreter der Echinodermen. Da die Seelilien in der Tiefsee leben, war es lange nicht möglich, lebende Exemplare für Laborstudien zu sammeln. Dank der Seelilie Metacrinus rotundus weiß man jetzt, wie sich diese Stachelhäuter entwickeln.
Lauschangriff auf Dickhäuter
Authors: Irsch Wilhelm 
Published: June 2003

AbstractBritischen Wildbiologen ist der Nachweis gelungen, dass jeder Elefant eine individuelle Stimme hat, an der man ihn auch über Kilometer hinweg identifizieren kann. Amerikanische Wissenschaftler der Cornell Universität in Ithaca haben deshalb in Zentralafrika Horchposten aufgestellt, mit deren Hilfe sie den Afrikanischen Elefanten (Loxodonta africana)vor dem Aussterben bewahren wollen.
Afferent connections of the parvocellular subparafascicular thalamic nucleus in the rat: Evidence for functional subdivisions
Authors: Coolen Lique M. , Veening Jan G. , Wells Adam B. , Shipley Michael T. 
Published: June 2003

AbstractThe parvocellular subparafascicular nucleus of the thalamus (SPFp) consists of separate subdivisions, i.e., a medial portion containing galanin‐immunoreactive (‐IR) axons and a lateral portion containing calcitonin gene related peptide (CGRP)‐IR neurons and fibers. These subdivisions appear to have distinct functional roles. In particular, ejaculation‐induced Fos expression is expressed in the medial SPFp. Hence, it was hypothesized that medial SPFp is involved in relay of copulation‐related information. In contrast, lateral SPFp is involved in the processing of auditory and visual signals involved in fear‐conditioned responses. Here we tested the hypothesis that medial and lateral subdivisions of SPFp receive different sets of afferents and that these differences contribute to the separate functional roles of the two subdivisions. Inputs to medial and lateral SPFp were identified following injections of FG restricted to either division in male rats. The medial SPFp receives unique inputs from lumbar spinothalamic cells and brain regions involved in processing of visceral stimuli, supporting the hypothesis that the medial SPFp is involved in the relay of genitosensory information critical for the expression of male sexual behavior. The afferents of the lateral SPFp include brain regions involved in processing of visual and auditory signals and support a role for this subdivision in relay of visual and auditory information. Thus, the two subdivisions of SPFp are anatomically and functionally distinctive. J. Comp. Neurol. 463:132–156, 2003. © 2003 Wiley‐Liss, Inc.
Parvocellular subparafascicular thalamic nucleus in the rat: Anatomical and functional compartmentalization
Authors: Coolen Lique M. , Veening Jan G. , Petersen Daniel W. , Shipley Michael T. 
Published: June 2003

AbstractThe parvocellular subparafascicular thalamic nucleus (SPFp) is located in the posterior thalamus, consists of horizontally oriented cells, and extends from rostromedial to caudolateral, fusing with the posterior intralaminar nucleus and the peripeduncular nucleus. The present study demonstrates a chemoarchitechtonic and functional parcellation of the rat SPFp. Analysis of the distributions of the neuropeptides galanin, calcitonin gene related peptide (CGRP), substance P, and calbindin revealed the existence of a medial and lateral subdivision within SPFp, and a possible intermediate subdivision. The medial subdivision contains a dense population of galanin‐immunoreactive fibers, originating from galanin neurons in the lumbosacral spinal cord. In contrast, the lateral subdivision contains CGRP‐positive fibers and neurons. The presence of substance P and calbindin immunoreactivity throughout the entire nucleus suggests that these are separate subdivisions of SPFp, rather than different subnuclei. The present study also investigated the functional association of the separate subdivisions of SPFp for male and female rat sexual behavior. In the medial subdivision, Fos‐positive neurons were activated in males by display of ejaculation and in females by vaginocervical stimulation. Thus, Fos induction in medial SPFp appears to reflect processing of inputs related to those events. In contrast, sexual behavior did not induce Fos in the lateral SPFp. Taken together, the present results indicate the existence of separate subdivisions in SPFp that are involved in different behavioral functions. The medial SPFp may process inputs important for sexual behavior, whereas the lateral SPFp may be involved in convergence of auditory and nociceptive inputs important for conditioned fear responses. J. Comp. Neurol. 463:117–131, 2003. © 2003 Wiley‐Liss, Inc.
Urocortin in the central nervous system of a primate (Cebus apella): Sequencing, immunohistochemical, and hybridization histochemical characterization
Authors: Vasconcelos Luciana A.P. , Donaldson Cynthia , Sita Luciane V. , Casatti Claudio A. , Lotfi Claudimara F.P. , Wang Liqun , Cadinouche M.Z. Alia , Frigo Lúcio , Elias Carol F. , Lovejoy David A. , Bittencourt Jackson C. 
Published: June 2003

AbstractThe urocortin (UCN)‐like immunoreactivity and UCN mRNA distribution in various regions of the nonprimate mammalian brain have been reported. However, the Edinger‐Westphal nucleus (EW) appears to be the only brain site where UCN expression is conserved across species. Although UCN peptides are present throughout vertebrate phylogeny, the functional roles of both UCN and EW remain poorly understood. Therefore, a study focused on UCN system organization in the primate brain is warranted. By using immunohistochemistry (single and double labeling) and in situ hybridization, we have characterized the organization of UCN‐expressing cells and fibers in the central nervous system and pituitary of the capuchin monkey (Cebus apella). In addition, the sequence of the prepro‐UCN was determined to establish the level of structural conservation relative to the human sequence. To understand the relationship of acetylcholine cells in the EW, a colocalization study comparing choline acetyltransferase (ChAT) and UCN was also performed. The cloned monkey prepro‐UCN is 95% identical to the human preprohormone across the matched sequences. By using an antiserum raised against rat UCN and a probe generated from human cDNA, we found that the EW is the dominant site for UCN expression, although UCN mRNA is also expressed in spinal cord lamina IX. Labeled axons and terminals were distributed diffusely throughout many brain regions and along the length of the spinal cord. Of particular interest were UCN‐immunoreactive inputs to the medial preoptic area, the paraventricular nucleus of the hypothalamus, the oral part of the spinal trigeminal nucleus, the flocculus of the cerebellum, and the spinal cord laminae VII and X. We found no UCN hybridization signal in the pituitary. In addition, we observed no colocalization between ChAT and UCN in EW neurons. Our results support the hypothesis that the UCN system might participate in the control of autonomic, endocrine, and sensorimotor functions in primates. J. Comp. Neurol. 463:157–175, 2003. © 2003 Wiley‐Liss, Inc.
Neurotrophin‐3 is expressed in a discrete subset of olfactory receptor neurons in the mouse
Authors: Vigers Alison J. , Böttger Bärbel , Baquet Zachary C. , Finger Thomas E. , Jones Kevin R. 
Published: June 2003

AbstractIn transgenic neurotrophin‐3 lacZ‐neo (NT‐3lacZneo) mice, in which the coding region for NT‐3 is replaced by Eschericia coli lacZ, the expression of β‐galactosidase faithfully mimics the expression of NT‐3 (Vigers AJ, Baquet ZC, Jones KR [2000], J Comp Neurol 416:398–416). During embryonic and early postnatal development, β‐galactosidase is detected in the olfactory system, beginning at embryonic day 11.5 in the nasal epithelium and at embryonic day 16.5 in the olfactory bulb. Levels of β‐galactosidase rise with age, reaching a peak during the second postnatal week, when β‐galactosidase reactivity is visible in up to 50% of the glomeruli. As the animal matures, the β‐galactosidase levels decline, but staining remains present in axons and cell bodies of a specific subset of olfactory receptor neurons (ORNs) projecting to a limited subset of glomeruli. The heavily labeled ORNs do not follow the typical OR expression zones in the epithelium but appear similar to the “patch” expression pattern of mOR37 receptors. The most heavily reactive glomeruli exhibit a striking reproducible pattern in the ventral olfactory bulb (OB). Some glomeruli of the OB contain calcitonin gene‐related peptide (CGRP)–immunoreactive fibers of the trigeminal nerve. However, double‐label immunocytochemistry for CGRP and β‐galactosidase rendered no correlation between trigeminal innervation and the degree of innervation by NT‐3–expressing ORNs. Thus, the timing and presence of β‐galactosidase in a subset of ORNs suggests that NT‐3 plays a role in synaptogenesis and/or synapse function in a specific subset of ORNs within the olfactory bulb. J. Comp. Neurol. 463:221–235, 2003. © 2003 Wiley‐Liss, Inc.