bluuebunny/crossref_metadata_2025 huggingface dataset:
Varieties of Properties
Authors: EARLEY JOSEPH E.
Published: July 2009

Abstract: The traditional distinction between primary (observation independent) and secondary (observation dependent) qualities is not based on a difference that can be sustained in the full light of contemporary scientific understanding. An alternative division of physical and chemical properties is proposed. Like the traditional division of qualities, the alternative system has two main categories. Properties of compound particulars that result from simple combination (e.g., addition) of the properties of their component parts constitute the first class: properties that depend on details of interactions between component parts (e.g. cooperative effects) make up the second type. Application of the alternative dichotomy is considered for the cases of mass (traditionally a primary property) and color (a secondary quality, in the usual division). Both these types of properties can fall in either of the two classes of the alternate division of qualities, depending on the nature of the interaction that occurs between components. Both mass and color show that intermediate cases occur. Application of the alternative categorical scheme is straightforward, but not always simple. The proposed system shows that in chemical combination (and, perforce, in the many more complex systems common in human culture) interactions profoundly influence properties of entities that enter the interaction. This is not adequately treated by philosophical theories of wholes and parts (mereology), which should be extended to apply to such important cases.
Property Reduction in Chemistry
Authors: VEMULAPALLI G. K.
Published: July 2009

Abstract: By taking molecules and atoms as models for wholes and parts, I explore the relation between the atomic and molecular properties in this article. Molecular properties do not reduce to atomic properties in the sense the former cannot be obtained by adding or multiplying the latter. However, quantum states of molecules are obtained from the quantum states of atoms by addition and multiplication. Because molecular properties are calculated reliably from the atomic states in quantum theory, it may be claimed that property reduction has been accomplished successfully. I show that such reduction entails underlying holism.
Paradoxes of Measurement
Authors: HEELAN PATRICK A.
Published: July 2009

Abstract: Applying Husserl's Eidetic Phenomenology to the transcendental structure (or ‘phenomenological reduction’) of scientific data ‘given’ in measurement to a first‐person individual observer (the experimenter, S1) and a related third‐person individual observer (the observer of the measurement process, S3), and comparing the outcomes, two paradoxical theses, ‘paradoxes of measurement,’ are derived. Thesis I: classical science necessarily entails ‘complementarity,’‘uncertainty relations,’ and the ‘entanglement’ of observers and the data they observe. This situation is analogous in structure to that of quantum physics. Thesis II: a quantum object is a physical object with footprints in the perceptual world, but lacking a space‐time ‘body’; it exists ontologically before the constitution of the perceptual world of the laboratory.
Reaction Mechanisms and Chemical Explanation
Authors: DEL RE GIUSEPPE
Published: July 2009

Abstract: The methodological and ontological issues arising in the organic chemists' explanation of transformations of matter by means of reaction mechanisms are presented based on the general view that chemistry is at the same time an autonomous discipline with its own paradigm and an integral part of the unitary body of science. Among the issues relevant to research is the nature and actual observability of activated complexes, which have by definition a vanishing lifetime. That issue illustrates the interplay of molecular chemistry and quantum physics at the submicroscopic level of sensible reality. A moral concerning the planning and strategy of research is briefly outlined.1
On the Ordinality of Causes in Complex Autocatalytic Systems
Authors: ULANOWICZ ROBERT E.
Published: July 2009

Abstract: The convention in chemical dynamics usually is to identify the reactant and catalytic molecules as the active agencies that combine in mechanical fashion to constitute a reaction process. When macromolecules grow large and complex enough to exhibit some plasticity, however, the subsequent directions in which these molecules change may be guided more by the nexus of chemical reactions in which they participate. In particular, configurations of autocatalytic reactions among plastic macromolecules can come to exert more agency upon the component reactants and mechanisms than vice versa, and the nexus of such processes retains its identity longer than do the latter, more transient participants. Whence, the ascendancy of autocatalytic forms as causal agencies provides a natural example of the phenomenon of ‘emergence’ and affords a way out of the conundrums that currently obfuscate the issue of the origin of life.
Chirality and Handedness
Authors: KING R. BRUCE
Published: July 2009

Abstract: Chirality and handedness are concepts that apply to the structure of molecules. Chirality is defined by the lack of certain features of symmetry, which lead to an object not being superimposable on its mirror image. Handedness is a different phenomenon relating to the ability to classify chiral objects into right‐handed and left‐handed objects. All handed objects are chiral, but not all chiral objects are handed. In 1968 through 1970, Ruch and coworkers developed a theory of chirality that provided a mathematical basis for the handedness of chiral objects. Handed chiral objects are considered to be analogous to shoes, which are readily classified into right and left shoes regardless of the size, material, style, or other attributes of the shoes in question. Nonhanded chiral objects are considered to be analogous to potatoes, which have no symmetry because of their irregular patterns of ‘bumps’ and ‘eyes,’ thereby meeting the lack of symmetry requirements for chirality. There is, however, no unambiguous way to classify a set of potatoes into ‘left’ and ‘right’ potatoes. In the case of molecules, a tetrahedron with four different substituents such as an asymmetric carbon atom in organic chemistry can readily be classified into right and left tetrahedra, as is typical for organic molecules in biological systems. An octahedral molecule with six different substituents, however, exhibits nonhanded chirality. For this reason, the fact that the key building block of natural products is a tetrahedral carbon atom rather than an octahedral atom of some type may be a critical factor in the handedness of many molecules found in biological structures.
How Harmful Is the First Law?
Authors: JOB GEORG , LANKAU TIMM
Published: July 2009

Abstract: In his First Law (of thermodynamics), Clausius emphasized the equivalence of heat and work—conservation of energy was mentioned only indirectly. Today, the main emphasis is put on energy conservation, but the equivalence of heat and work has proven not only to be superfluous, but also highly destructive. Because of this emphasis, heat is no longer considered an independent entity. In the guise of the quantity Q heat acts in a strange double role—an entity equivalent to work, but also as something fundamentally different. The place formerly occupied by heat is now filled with an abstract quantity, the entropy S—a phantom without macroscopically relevant properties. By using a phenomenological approach to entropy, it can be shown that entropy S does indeed have easily comprehensible macroscopic properties. This approach can be used to simplify thermodynamic reasoning and to reduce the calculus of thermodynamics to a fraction of its usual extent.
Symmetry in Basic Physical Laws
Authors: KÜHL ELMAR , LANKAU TIMM
Published: July 2009

Abstract: Recent physical experiments suggest that chirality is not a purely chemical phenomenon, but seems to be an inherent feature of basic physical laws. A fundamental physical principle (the CPT theorem) connects asymmetry in space with the ‘arrow of time,’ and shows that such an arrow exists even on the level of mesons.
‘Causes’ in Chemical Explanations
Authors: STEMWEDEL JANET D.
Published: July 2009

Abstract: Chemists talk about causes and make frequent use of the verb ‘to cause.’ They use the verb ‘to cause’ for its generality in identifying causal chains, whether all the details of those chains are established or some remain unclear. Most of these causal chains bottom out in attractions and repulsions. Attractions and repulsions are causal relations that are chemically basic; chemistry has no further story to tell about why attraction and repulsion are causal. If there is some further story to tell about the causal status of attraction and repulsion, it is left to physics to tell it, but it is not obvious that the absence of such a story would prevent chemists from using attractions and repulsions in their causal explanations.
John Dalton and the Aesthetics of Molecular Representation
Authors: SPECTOR TAMI I.
Published: July 2009

Abstract: This paper examines the negative response to Dalton's symbolism in the context of the representational system of affinity tables. When situated in an iconoclastic scientific culture that rejected overt speculation, affinity tables reflected a functionalist empirical aesthetic, while Dalton's symbols embraced a deductive aesthetic suggestive of alchemical iconography.
Writing as Thinking
Authors: KOVAC JEFFREY
Published: July 2009

Abstract:In this article I try to sketch preliminary answers to several questions. (1) What is the role of writing in science? (2) How can rhetorical analysis illuminate the nature of scientific writing? (3) What is the role of models and metaphors in scientific thinking and writing? Since this is a preliminary inquiry, my remarks are brief and suggestive, but I think they point to some profitable directions for further study.
Statement Analysis in Chemistry
Authors: JACOB CLAUS
Published: July 2009

Abstract: Close philosophical examination of chemical research reports (‘statement analysis’) can lead to clarification of ambiguities and resolution of logical confusions, and also lead to other useful conclusions.
Beyond the Dimensionality of Visualization in Chemistry
Authors: BUREWICZ ANDRZEJ , MIRANOWICZ NIKODEM
Published: July 2009

Abstract: This article elaborates a key aspect of applied visualization in chemistry: dimensionality. On the one hand, the dimensionality of visualization is restricted by the medium of information transfer; on the other hand, several techniques make it possible to achieve visualizations of parameters of multidimensional objects of chemical research in ways that, in a sense, transcend the limits of the physical space‐time continuum. Effectiveness of chemistry research, as well as of chemical education, requires proper perception of parameters of objects being investigated. The appropriate application of visualization techniques can be crucial.
Justifying Instrumental Techniques of Analytical Chemistry
Authors: ROTHBART DANIEL , KOHOUT LADISLAV
Published: July 2009

Abstract: In this paper, we argue that the foundations of chemistry rely as much on the methods of measurement as they do on categories of chemical substance. To some degree, chemists perform the work of knowledge engineering: designing complex systems for the efficient retrieval of information. Indeed, in some cases, methods of instrumental detection move to the forefront of attention. For example, researchers are expected to deploy optimization methods designed to maximize desired signal and minimize the damaging effects of noise. But in his important contributions to the development of high‐resolution NMR spectrometers, Hans Primas used stochastic methods to reveal beneficial effects of noise for characterizing physical systems, demonstrating the value of noisy signals for nonlinear physical systems in chemistry.
Richard Rufus's Theory of Mixture
Authors: WEISBERG MICHAEL , WOOD REGA
Published: July 2009

Abstract: Richard Rufus of Cornwall offered a novel solution to the problem of mixture raised by Aristotle. The puzzle is that mixts or mixed bodies (blood, flesh, wood, etc.) seem to be unexplainable through logic, even though the world is full of them. Rufus's contribution to this long‐standing theoretical debate is the development of a modal interpretation of certain Averroistic doctrines. Rufus's account, which posits that the elemental forms in a mixt are in accidental potential, avoids many of the problems that plagued non‐atomistic medieval theories of mixture. This paper is an initial examination of Rufus' account.
The Lavoisier‐Kirwan Debate and Approaches to the Evaluation of Theories
Authors: AKEROYD MICHAEL
Published: July 2009

Abstract: This paper applies concepts proposed by Larry Laudan for evaluation of scientific theories to problems that arose for Antoine Lavoisier's oxygen theory during the period from 1780 to 1790. Lavoisier's original theory (1779) had an empirical problem (why does dilute sulfuric acid produce hydrogen on contact with metals, whereas concentrated acid, even when heated, does not?). The solution to this puzzle led to a more refined conceptual problem, regarding the overall consistency of the theory. Conceptual arguments used by the French school of chemists to defend Antoine Lavoisier's oxygen theory against the phlogistic arguments (1784) of Richard Kirwan touch on the problem of criteria for satisfactory explanation.
The Superiority of ‘Chemical Thinking’ for Understanding Free Human Society According to Hegel
Authors: NOWACKI MARK R. , VER EECKE WILFRIED
Published: July 2009

Abstract: This paper examines the claim of G.W.F. Hegel (1770–1831) that ‘chemical thinking’—the method of thinking employed in chemistry—marks a significant advance upon (and hence is superior to) ‘mechanistic thinking’—the method of thinking characteristic of physics. This is done in the context of Mancur Olson's theory of collective action and public goods. The analogy between the efficiency of a catalyst in bringing about chemical transformation and the function of leaders in free human society in developing latent groups to provide public goods is explored.
Crystal Structures of Ca2+‐ATPase in Various Physiological States
Authors: TOYOSHIMA CHIKASHI , NOMURA HIROMI , SUGITA YUJI
Published: July 2009

Abstract: The structures of the Ca2+‐ATPase (SERCA1a) in different physiological states were determined by X‐ray crystallography. Detailed comparison of the structures in the Ca2+‐bound form and unbound (but thapsigargin bound) form reveals that very large rearrangements of the transmembrane helices take place accompanying Ca2+ dissociation and binding and that they are mechanically linked with equally large movements of the cytoplasmic domains. The meaning of the rearrangement of the transmembrane helices becomes apparent by homology modeling of the Na+K+‐ATPase.
Conformational Dynamics of Na+/K+‐ and H+/K+‐ATPase Probed by Voltage Clamp Fluorometry
Authors: GEIBEL SVEN , ZIMMERMANN DIRK , ZIFARELLI GIOVANNI , BECKER ANJA , KOENDERINK JAN B. , HU YI‐KANG , KAPLAN JACK H. , FRIEDRICH THOMAS , BAMBERG ERNST
Published: July 2009

Abstract: We used the method of site‐directed fluorescence labeling in combination with voltage‐clamp fluorometry for time‐resolved recording of localized conformational transitions of the Na+/K+‐ and H+/K+‐ATPase. Therefore, single cysteine mutations were introduced into the extracellular TM5‐TM6 loop of the sheep Na+/K+‐ATPase α1‐subunit devoid of other extracellular cysteines. Upon expression in Xenopus oocytes and covalent attachment of tetramethylrhodamine‐maleimide (TMRM) as a reporter fluorophore, Cys‐mutant N790C showed large fluorescence changes of up to 5% in response to extracellular K+ that were completely abolished by ouabain. When voltage jumps were applied under Na+/Na+‐exchange conditions, we observed fluorescence changes that paralleled the transient currents originating from the E1P↔E2P transition. These fluorescence changes were also completely inhibited by ouabain, as were the voltage jump‐induced transient currents. Transient fluorescence changes could also be measured as a function of increasing K+ concentrations, that is, under turnover conditions. As a result, the distribution between E1 and E2 states can be determined at any time and membrane potential. Very similar fluorescence signals were obtained for rat gastric H+/K+‐ATPase upon expression in oocytes, when a single cysteine was introduced at a position homologous to N790 in Na+/K+‐ATPase for attachment of the fluorophore. As to the high sequence similarity among P‐type ATPases within the TM5 helix and the TM5‐TM6 loop region, our results enable new means of kinetic investigation for these pumps under physiological conditions in living cells.
Characterization of Ca2+ ATPase Residues Involved in Substrate and Cation Binding
Authors: INESI GIUSEPPE , MA HAILUN , HUA SUMING , TOYOSHIMA CHIKASHI
Published: July 2009

Abstract: The role of amino acid residues involved in substrate and cation binding was investigated in complementary experiments on Fe2+‐catalyzed oxidation and cleavage, limited digestion with proteinase K, and mutational analysis. Cleavage at Ser346 was produced by Fe2+ in the presence of substrate (ATP or AMP‐PNP) and Ca2+, and was attributed to Fe2+ bound to a Mg2+ site near Ser346 and neighboring Glu696. Ca2+‐ and ATP‐dependent oxidation of the Thr441 side chain was also observed and attributed to Fe2+ substituting for Mg2+ in the Mg2+‐ATP complex bound to the N domain. Mutation of Arg560 or Glu439 within the N domain interfered with nucleotide‐dependent ATPase resistance to digestion with proteinase K. Furthermore, mutation of Lys352, Lys684, Thr353, Asp703, or Asp707 within the P domain produced similar interference, consistent with a role of these residues in substrate stabilization at the catalytic site. In a third group of experiments, equilibrium isotherms were obtained with Asn796Ala and Glu309Gln mutants, demonstrating non‐cooperative binding of one Ca2+ per ATPase, as opposed to cooperative binding of two Ca2+ by WT enzyme. No high‐affinity binding by Asp800Asn, Glu771Gln, and Thr799Ala mutants was detected. It was also demonstrated that the conformational transitions involved in enzyme activation and interconversion of Ca2+ binding and phosphorylation energy, are triggered by Ca2+ binding to site II and stabilization of Glu309 (M4) and N796 (M6).
Two‐Electrode Voltage‐Clamp Analysis of Na,K‐ATPase Asparagine 776 Mutants
Authors: KOENDERINK JAN B. , GEIBEL SVEN , GRABSCH EVA , DE PONT JAN JOEP H. H. M. , BAMBERG ERNST , FRIEDRICH THOMAS
Published: July 2009

Abstract: Steady‐state and pre‐steady‐state currents of Asn776 mutants of Na,K‐ATPase are presented. The stationary current generated by N776Q strongly depends on the membrane potential, but has a negative slope, opposite to that of the wild‐type enzyme. The apparent rate constant of the reaction sequence E1P(Na+) ↔ E2P + Na+ of this mutant is rather independent of the membrane potential and is at resting and depolarizing membrane potential higher than that of the wild‐type enzyme. Thus, the voltage‐dependent increase of the rate coefficient of the wild type that is associated with extracellular Na+ rebinding is almost absent in the N776Q mutant. These findings indicate that dislocating the carboxamide group of Asn776 decreases the affinity of sodium at its extracellular binding site.
Homology Modeling of Na,K‐ATPase
Authors: HÅKANSSON K. O. , JORGENSEN P. L.
Published: July 2009

Identification of the third Na+ binding site would be crucial in interpretation of the electrophysiological behavior of Na,K‐ATPase. To address this question a three‐dimensional homology model of Na,K‐ATPase was built from the known crystallographic structure of Ca‐ATPase (1EUL). Phe760, which is conserved in virtually all Ca‐ATPases, is replaced by Ser768 in Na,K‐ATPase, resulting in a small cavity between M4, M5, and M6. A partially hydrated Na+ ion can be bound at this third site on the cytoplasmic side of cation binding sites 1 and 2. This leads to the proposal that the conductance of the ‘third Na+’ ion across ∼70% of the membrane dielectric may be achieved by adding up the passage of one Na+ ion from the described cytoplasmic cavity to cation site 1 and the further conductance of the previously bound Na+ ion from cation site 1 to the extracellular phase. This relay mechanism may therefore be compatible with the electrogenic profile of Na+ translocation.
Use of a Fluorescent Maleimide to Probe Structure‐Function Relationships in Stalk Segments 4 and 5 of the Yeast Plasma‐Membrane H+‐ATPase
Authors: SLAYMAN CAROLYN W. , MIRANDA MANUEL , PARDO JUAN PABLO , ALLEN KENNETH E.
Published: July 2009

Abstract: In the yeast plasma‐membrane H+‐ATPase and other P‐type ATPases, conformational changes are transmitted between cytoplasmic and membrane‐embedded domains via a stalk region composed of cytoplasmic extensions of membrane segments 2, 3, 4, and 5. The present study has used a fluorescent maleimide (Alexa‐488) to probe Cys residues introduced into stalk segments 4 and 5 of the yeast enzyme. In the case of S5, Cys substitutions along one face led to a constitutive, 5‐ to 10‐fold activation of the ATPase in the absence of glucose. Based on homology with SERCA Ca2+‐ATPase, this face is likely to be buried in the interior of the protein, close to the P domain. Three Cys residues on the opposite face of S5 (A668C, S672C, and D676C) were accessible to Alexa‐488 under all conditions tested. In addition, three other Cys residues at or near the boundary between the two faces reacted with Alexa‐488 only (V665C, L678C) or preferentially (Y689C) in plasma membranes from glucose‐metabolizing cells; this result provides the first direct evidence for a change in conformation of S5 during glucose activation. For stalk segment 4, site‐directed mutagenesis gave no sign of a role in glucose‐dependent regulation. Rather, substitutions at 13 consecutive positions along S4 caused kinetic changes consistent with a shift in equilibrium from E2 to E1. Four Cys residues along this stretch of S4 (Q357C, K362C, S364C, and S368C) reacted with Alexa‐488, indicating that they are exposed to the aqueous medium as predicted in the SERCA‐based structural model.
Nongastric H,K‐ATPase: Structure and Functional Properties
Authors: MODYANOV NIKOLAI , PESTOV NIKOLAY , ADAMS GAIL , CRAMBERT GILLES , TILLEKERATNE MANORANJANI , ZHAO HAO , KORNEENKO TATYANA , SHAKHPARONOV MIKHAIL , GEERING KATHI
Published: July 2009

Abstract: Nongastric H,K‐ATPases whose catalytic subunits (AL1) encoded by human ATP1AL1 and homologous animal genes comprise the third distinct group within the X,K‐ATPase family. No unique nongastric β has been identified. Precise in situ colocalization and strong association of AL1 with β1 of Na,K‐ATPase was detected in apical membranes of rodent prostate epithelium. In this tissue, β1NK serves as an authentic subunit of both the Na,K‐ and nongastric H,K‐pumps. Upon expression in Xenopus oocytes the human AL1 can assemble with β1NK, and more efficiently with gastric βHK, into functional H,K‐pumps. Both AL1/β complexes exhibit a similar K‐affinity, and their K‐transport depends on intra‐ and extracellular Na. These data provide new evidence that nongastric H,K‐ATPase can perform Na/K‐exchange, and indicate that β does not significantly affect this ion‐pump function. Analysis of human nongastric H,K‐ATPase expressed in Sf‐21 insect cells revealed that AL1/βHK exhibits substantial enzymatic activities in K‐free medium and K stimulates, but Na has inhibitory effect on ATP hydrolysis. Thus, although the nongastric H,K‐ATPase can function as Na/K exchanger, its reaction mechanism is different from that of the Na,K‐ATPase. Human nongastric H,K‐ATPase is highly sensitive to bufalin, digoxin, and digitoxin, but almost resistant to digoxigenin and ouabagenin.
Mechanism of Proton Pumping by Plant Plasma Membrane H+‐ATPase
Authors: PALMGREN M. G. , BUCH‐PEDERSEN M. J. , MØLLER A. L.
Published: July 2009

Abstract: The mechanism of proton pumping by P‐type plasma membrane H+‐ATPases is not well clarified. Site‐directed mutagenesis studies suggest that Asp684, situated in transmembrane segment M6, is involved in coordination of proton(s) in plant plasma membrane H+‐ATPase. This hypothesis is supported by atomic models of H+‐ATPases built on the basis of the crystal structure of the related SERCA1a Ca2+‐ATPase. However, more biochemical, genetic, and structural studies are required before we will be able to understand the nature of the proton binding site(s) in P‐type H+‐ATPases and the mechanism of action of these pumps.
A Specific Functional Interaction between CHIF and Na,K‐ATPase
Authors: GARTY HAIM , LINDZEN MOSHIT , FÜZESI MARIA , AIZMAN ROMAN , GOLDSHLEGER RIVKA , ASHER CAROL , KARLISH STEVEN J. D.
Published: July 2009

Abstract: CHIF (corticosteroid hormone‐induced factor) is a member of the FXYD family that shares ∼50% homology with the γ subunit of Na,K‐ATPase. It is expressed in renal collecting duct and distal colon, and is upregulated by Na+ deprivation and high K+ diet. Both CHIF and γ are coimmunoprecipitated by an anti‐α subunit antibody, and α is immunoprecipitated by anti‐γ and anti‐CHIF antibodies. 86Rb+ flux experiments in CHIF‐transfected HeLa cells demonstrate that CHIF increases the affinity for cytoplasmic Na+, but does not affect the affinity for extracellular K(Rb). A physiological role of CHIF in kidney function is further elucidated by the phenotypic analysis of CHIF knockout mice. Taken together with data by others, it appears that FXYD proteins are tissue‐specific subunits or regulators of the Na,K‐ATPase whose function is to adjust the pump kinetics to particular physiological needs.
Physiological Functions of Plasma Membrane and Intracellular Ca2+ Pumps Revealed by Analysis of Null Mutants
Authors: SHULL GARY E. , OKUNADE GBOLAHAN , LIU LYNNE H. , KOZEL PETER , PERIASAMY MUTHU , LORENZ JOHN N. , PRASAD VIKRAM
Published: July 2009

Abstract: It is known that plasma membrane Ca2+‐transporting ATPases (PMCAs) extrude Ca2+ from the cell and that sarco(endo)plasmic reticulum Ca2+‐ATPases (SERCAs) and secretory pathway Ca2+‐ATPases (SPCAs) sequester Ca2+ in intracellular organelles; however, the specific physiological functions of individual isoforms are less well understood. This information is beginning to emerge from studies of mice and humans carrying null mutations in the corresponding genes. Mice with targeted or spontaneous mutations in plasma membrane Ca2+‐ATPase isoform 2 (PMCA2) are profoundly deaf and have a balance defect due to the loss of PMCA2 in sensory hair cells of the inner ear. In humans, mutations in SERCA1 (ATP2A1) cause Brody disease, an impairment of skeletal muscle relaxation; loss of one copy of the SERCA2 (ATP2A2) gene causes Darier disease, a skin disorder; and loss of one copy of the SPCA1 (ATP2C1) gene causes Hailey‐Hailey disease, another skin disorder. In the mouse, SERCA2 null mutants do not survive to birth, and heterozygous SERCA2 mutants have impaired cardiac performance and a high incidence of squamous cell cancers. SERCA3 null mutants survive and appear healthy, but endothelium‐dependent relaxation of vascular smooth muscle is impaired and Ca2+ signaling is altered in pancreatic β cells. The diversity of phenotypes indicates that the various Ca2+‐transporting ATPase isoforms serve very different physiological functions.
Visualization of Na,K‐ATPase Interacting Proteins Using FRET Technique
Authors: UHLÉN PER
Published: July 2009

Abstract: Signaling transduction mediated by protein aggregates within specific microdomains has been receiving increased attention. We previously showed that Na,K‐ATPase, partially inhibited by ouabain, induces intracellular calcium (Ca2+) oscillations which involve Ca2+ release from the endoplasmic reticulum (ER). Plasma membrane bound Na,K‐ATPase and proteins in the ER are in close proximity to each other, and signal transduction may occur via a physical interaction or a microdomain. To study these signaling pathways and intricate microenvironments, sophisticated methods are required. One way to detect molecular interactions in the nanometer scale (1‐10 nm) is fluorescence resonance energy transfer (FRET). Thus, FRET provides vital insight into the action of Na,K‐ATPase to trigger intracellular signaling events.
Short‐Term Aldosterone Action on Na,K‐ATPase Surface Expression
Authors: VERREY FRANÇOIS , SUMMA VANESSA , HEITZMANN DIRK , MORDASINI DAVID , VANDEWALLE ALAIN , FERAILLE ERIC , ZECEVIC MARIJA
Published: July 2009

Abstract: Aldosterone controls extracellular volume and blood pressure by regulating Na+ reabsorption across epithelial cells of the aldosterone‐sensitive distal nephron (ASDN). This effect is mediated by a coordinate action on the luminal channel ENaC (generally rate limiting) and the basolateral Na,K‐ATPase. Long‐term effects of aldosterone (starting within 3 to 6 hours and increasing over days) are mediated by the direct and indirect induction of stable elements of the Na+ transport machinery (e.g., Na,K‐ATPase α subunit), whereas short‐term effects appear to be mediated by the upregulation of short‐lived elements of the machinery (e.g., ENaC α subunit) and of regulatory proteins, such as the serum‐ and glucocorticoid‐regulated kinase SGK1. We have recently shown that in cortical collecting duct (CCD) from adrenalectomized (ADX) rats, the increase in Na,K‐ATPase activity (approximately threefold in 3 h), induced by a single aldosterone injection, can be fully accounted for by the increase in Na,K‐ATPase cell‐surface expression. Using the model cell line mpkCCDcl4, we showed that the parallel increase in Na,K‐ATPase function [assessed by Na+ pump current (Ip) measurements] and cell‐surface expression depends on transcription and translation, and that it is not secondary to a change in apical Na+ influx. As a first approach to address the question whether the aldosterone‐induced regulatory protein SGK1 might play a role in mediating Na,K‐ATPase translocation, we have used the Xenopus laevis expression system. SGK1 coexpression indeed increased both the Na+ pump current and the surface expression of pumps containing the rat α1 subunits. In summary, aldosterone controls Na+ reabsorption in the short term not only by regulating the apical cell‐surface expression of ENaC but also by coordinately acting on the basolateral cell‐surface expression of the Na,K‐ATPase. Results obtained in the Xenopus oocyte expression system suggest the possibility that this effect could be mediated in part by the aldosterone‐induced kinase SGK1.
Genetics of Hypertension: The Adducin Paradigm
Authors: BIANCHI GIUSEPPE , TRIPODI GRAZIA
Published: July 2009

Abstract: The following were investigated: (1) how we became interested in studying adducin genes and what we know about adducin; (2) studies in animals and humans supporting the role of adducin polymorphisms in hypertension, including some methodological problems related to the dissection of the role of a given genetic molecular mechanism in a complex multifactorial polygenic disease like hypertension; (3) biochemical mechanisms underlying the effect of adducin and its interaction with the Na‐K pump; and (4) future directions.
Myocardial Na,K‐ATPase and Digoxin Therapy in Human Heart Failure
Authors: KJELDSEN KELD , BUNDGAARD HENNING
Published: July 2009

Abstract:The specific binding of digitalis glycosides to the Na,K‐ATPase is used as a tool for Na,K‐ATPase quantification with high accuracy and precision. In myocardial biopsies from patients with heart failure, total Na,K‐ATPase concentration is decreased, and the decrease in Na,K‐ATPase concentration correlates with a decrease in heart function. During digitalization, a fraction of remaining pumps are occupied by digoxin. No evidence for an endogenous digitalis‐like factor of any clinical importance was obtained. It is recommended that digoxin be administered to heart failure patients who still have dyspnea after institution of mortality‐reducing therapy.
Rickettsiosis of the Genus Rickettsia in South America
Authors: GALVÃO MÁRCIO A.M. , MAFRA CLÁUDIO L. , MORON CECÍLIA , ANAYA ELIZABETH , WALKER DAVID H.
Published: July 2009

Abstract: In South America, human cases of infection by the genus Rickettsia have been described in several countries in the last twenty years. The role of international organizations, such as the Centers for Disease Control and Prevention in Atlanta, Georgia, USA and the World Health Organization Collaborating Center for Tropical Diseases at the University of Texas Medical Branch at Galveston, Texas, USA, was very important in the last twenty years for the development of surveillance systems and for the increase in notification of rickettsial diseases by the countries of South America. We hope that the next goal will be prevention and control of rickettsial diseases in the countries of South America, as well as maintaining the programs developed during the last twenty years, so that a good health system and improved social conditions will be possible.
Transmission Efficiency of the AP‐Variant 1 Strain of Anaplasma phagocytophila
Authors: MASSUNG ROBERT F. , MATHER THOMAS N. , PRIESTLEY RACHAEL A. , LEVIN MICHAEL L.
Published: July 2009

Abstract: Nymphal Ixodes scapularis ticks were collected from several sites in Rhode Island. DNA was extracted from a subset of these ticks, and PCR and DNA sequencing of the 16S rRNA gene were used to determine the ratio of Anaplasma phagocytophila‐human agent (AP‐ha) to a genetic variant not associated with human disease (AP‐Variant 1). The remaining ticks were allowed to feed to repletion on either white‐footed (Peromyscus leucopus) or DBA/2 (Mus musculus) mice. The engorged ticks, and blood samples drawn from each mouse at one‐week intervals, were evaluated by PCR and DNA sequencing for the presence of AP‐ha and Variant 1. Although a high percentage of the infecting ticks harbored AP‐Variant 1, only AP‐ha was amplified from the mouse blood samples. Because the A. phagocytophila variant did not establish an infection either in the natural reservoir of AP‐ha, the white‐footed mouse, or in a common research laboratory mouse (DBA/2), AP‐Variant 1 may have an alternative natural reservoir, possibly the white‐tailed deer.
Molecular Epidemiological Study for Tick‐Borne Disease (EhrlichiaandAnaplasmaspp.) Surveillance at Selected U.S. Military Training Sites/Installations in Korea
Authors: CHAE JOON‐SEOK , KIM CHUL‐MIN , KIM EUN‐HA , HUR EUN‐JEONG , KLEIN TERRY A. , KANG TAE‐KYU , LEE HEE‐CHOON , SONG JIN‐WON
Published: July 2009

Abstract:Vector‐borne diseases are a potential public health threat to U.S. Forces Korea (USFK).EhrlichiaandAnaplasmaspp., transmitted by ticks, are only two of several diseases that may affect military readiness and operations. Rodents were collected at selected U.S. military installations and training sites in the Republic of Korea. DNA was extracted from spleen tissues and assayed by PCR methods forEhrlichiaandAnaplasmaspecies. From rodents and mustelids collected during 1999 and 2000, a total of 196Apodemus agrarius(striped field mouse), 2Mustela sibirica(weasel), and 1Cricetulus triton nestor(Korean greater long‐tailed hamster) were assayed forEhrlichiaandAnaplasmaspecies‐specific DNA fragments. Rodent surveillance indicated a very high prevalence ofEhrlichiaandAnaplasmaspp. at selected training sites.Ehrlichia/AnaplasmaDNA were identified from spleen tissue from 157Apodemus agrarius, 1Mustela sibirica, and 1Cricetulus riton nestor. Species‐specific DNA fragments ofE. canis(45),E. ewingii(16),A. phagocytophila(5), andA. platys(62) were amplified by PCR techniques. Seventy‐one striped field mice had single infections, while 24 had mixed infections of 2 (17 specimens), 3 (7 specimens), or 4 (1 specimen) pathogens. The striped field mouse plays a role as a reservoir for latent infections of variousEhrlichiaorAnaplasma species.
Ehrlichiosis and Rickettsiosis in a Canine Population of Northern Sardinia
Authors: COCCO R. , SANNA G. , CILLARA M. G. , TOLA S. , XIMENES L. , PINNAPARPAGLIA M. L. , MASALA G.
Published: July 2009

Abstract: Ehrlichiosis and rickettsiosis are very common, widespread diseases. These diseases are present in Sardinia year round because its temperate weather permits the survival of many kinds of tick vectors. A thousand dogs were subjected to physical, hematological, biochemical examinations and serological tests. All 1,000 sera were analyzed by indirect immunofluorescence antibody test to detect antibodies against E. canis and R. rickettsii. A high seroprevalence (about 50%) was detected for both etiological agents, without differences in relation to sex, breed, or usage. A high seroprevalence, corresponding to 62.5% for ehrlichiosis and 64% for rickettsiosis, was observed in the age group of 13–60 months. The mortality was greatest in the males in the age group, which manifested the disease in the chronic phase.
Detection of R. felis and R. typhi in Fleas Using Monoclonal Antibodies
Authors: FANG R. , FOURNIER P. E. , HOUHAMDI L. , AZAD A. F. , RAOULT D.
Published: July 2009

Abstract: Rickettsia typhi and R. felis are flea‐transmitted human pathogenic rickettsial species. To investigate the distributional dynamics of these rickettsiae we designed a micro‐immunofluorescence assay (MIF) using species‐specific monoclonal antibodies (MAbs) applied to flea cryosections. Our assay was performed in less than 3 h and its applicability was demonstrated by the detection of R. typhi in 50 artificially infected human body lice but in none of 50 uninfected lice. With MIF, we identified 31 positive among 32 fleas proven with PCR to be naturally infected with R. felis; and 7 positive among 32 fleas proven with PCR to be naturally infected with R. typhi. No cross‐detection was observed with both MAbs. Fresh R. felis‐infected fleas were significantly more MIF‐positive than long conserved R. typhi‐infected fleas (31/32 vs. 7/32, P < 0.01). This discrepancy may be linked to degradation of antigens by long‐term freezing. For R. typhi‐infected fleas, our assay was significantly more efficient when applied to fleas in early stages of infection (less than 15 days) by comparison with fleas frozen more than 20 days after infection (7/15 vs. 0/17, P= 0.01). This difference may be related to an antigenic modification caused by selection pressure in the vector and host process. The sensitivity of the described method did not exceed 47% (7/15) for R. typhi but, in contrast, was 97% for R. felis. Thus, our method appears to be useful for surveillance in R. felis infections, but requires further studies for the detection of R. typhi.
Identification of Trematode Cercariae Carrying Neorickettsia risticii in Freshwater Stream Snails
Authors: PARK BAE‐KEUN , KIM MEEN‐JU , KIM EUN‐HA , KIM MIN‐SEOK , NA DONG‐GYUN , CHAE JOON‐SEOK
Published: July 2009

Abstract: We provide evidence of Neorickettsia (Ehrlichia) risticii Holland, the agent of Potomac horse fever, in trematode larval stages found in aquatic snails and insects collected from a stream in Korea, using nested polymerase chain reaction (PCR) and sequence analysis of the 16S rRNA gene fragment amplified from several cercaria species. It was observed that of 423 (13.1%) of 3,219 snails infected with cercariae, 77 (20.8% of the 371) were infected with N. risticii. Five families of trematode cercariae, Schistosomatidae, Echimostomatidae, Heterophyidae, Microphallidae, and Acanthocopidae were identified morphologically within Semisulcospira libertina, Radix auricularia coreana, and S. gottschei snails. Echinostoma cinetorchis, E. hortense, and Metagonimus sp. were identified based on both the cercarial morphology as well as by phylogenetic analysis of the amplified 18S rRNA gene sequences. Adult aquatic insects were also collected from the same sites and were sorted into five species, Ischnura asiatica in Coenagrionidae and Calopteryx japonica, Sympetrum darwinianum, Symptrum eroticum, and Symptrum parvulum in Calopterygoidae. One thousand and two hundred eighty five metacercariae (classified into groups A through F) were isolated from 310 adult aquatic insects, and the average number of metacercariae per aquatic insect was 4.1. However, there was no amplification of N. risticii from these metacercariae.
Equine Ehrlichiosis in Italy
Authors: SCARPULLA MANUELA , CARISTO MARIA EMILIANA , MACRI GLADIA , LILLINI EUGENIO
Published: July 2009

Abstract:The authors review equine granulocytic ehrlichiosis (EGE) in Italy from 1996 to 2002. In 1996, the first case of EGE has been observed in a horse affected with specific symptomatology (fever, lethargy, anorexia, limb edema, thrombocytopenia, and petechiae). In 1997, a seroepidemiological survey was performed in the province of Rome on 563 animals using IFAT. The authors describe the last case, which occurred on 2002 in a 15‐year‐old male, bay, half‐breed, tick‐infested horse. Clinical features included fever, lethargy, limb edema, icterus, leukocytopenia, and thrombocytopenia. Laboratory tests were positive for ELISA and IFAT and several morulae were seen in the cytoplasm of neutrophils in buffy coat smears. The authors think that in Italy the prevalence of EGE is underestimated because of the nonpathognomonic clinical symptoms, the diffusion of specific infected vector, and the nonroutine nature of specific laboratory tests.
Rickettsiosis Caused by Rickettsia conorii in Uruguay
Authors: DÍAZ ISMAEL A. CONTI
Published: July 2009

Abstract: The first three human cases of rickettsiosis caused by Rickettsia conorii in Montevideo, Uruguay were described in 1990. All of them showed an initial papulosquamous lesion on the scalp from a canine tick bite (Amblyomma triste). At the same time, fever and regional adenopathies were observed. Serological diagnosis was made by the indirect IgM immunofluorescent technique on glass smears of R. conorii (Biomerieux Laboratories, France). All patients had a benign disease course after been treated with oral tetracyclines. Other authors later developed clinical and serological studies for R. conorii rickettsiosis in a nearby county, confirming our original findings. The tache noir and a light exanthema were also noticed. We have seen several similar cases since that date. Most of them were from rural areas, and two presented with the classical tache noir and a maculopapular rash with severe symptomatology. A. triste, a South American tick with deep anthropophilia, appears as the usual transmitting vector of the disease in the country. A review of the literature reveals a very intriguing absence of similar cases in the Americas including the USA. New studies are necessary to resolve this issue. The possibility that a new species of rickettsia responsible for the disease in Uruguay is also considered.
Real‐Time PCR Duplex Assay for Rickettsia prowazekii and Borrelia recurrentis
Authors: JIANG J.U. , TEMENAK JOSEPH J. , RICHARDS ALLEN L.
Published: July 2009

Abstract: Rickettsia prowazekii, the etiologic agent for epidemic typhus, and Borrelia recurrentis, the etiologic agent of relapsing fever, both utilize the same vector, the human body louse (Pediculus humanus), to transmit human disease. We have developed an assay to detect both bacterial pathogens in a single tube utilizing real‐time PCR. Assays for both agents are specific. The R. prowazekii and B. recurrentis assays do not detect nucleic acid from R. typhi, R. canada, or any of eight spotted fever rickettsiae. In addition they did not react with Neorickettsia risticii, N. sennetsu, Franciscella persica, Bartonella quintana, Legionella pneumophila, Proteus mirabilis, Salmonella enterica, Escherichia coli, and Staphylococcus aureus. Moreover, the B. recurrentis assay did not detect B. duttonii, B. coriaceae, B. afzelii, B. garinii, B. hermsii, or B. burgdorferi nucleic acid. Both assays detected repeatedly only R. prowazekii or B. recurrentis either when tested alone or together in one test tube.
Significance of Q Fever Serologic Diagnosis in Clinically Suspect Patients
Authors: HAMZIĆ S. , BESLAGIĆ E. , ZVIZDIĆ Š.
Published: July 2009

Abstract: Q fever is caused by C. burnetii, an intracellular obligate bacterium. For clinical confirmation of Q fever, diagnosis of interstitial pneumonia is of significance. The acute disease varies in severity from minor to fatal, with the possibility of serious complications. Chronic endocarditis is a well‐known outcome. Symptoms of Q fever can vary; fixing diagnosis is done by serology with the phase I and the phase II antibody. We tested 44 sera of 31 clinically suspect patients. From these, 22 patients were taken to the infection clinic, 8 to the pulmonary clinic, and one to the general hospital. From the 31 patients, 21 patients had one serum, 7 patients, 2 sera, and 3 patients, 3 sera. Blood samples were collected by vein puncture, and serum samples were kept at −20°C until testing. All sera were processed by indirect imunofluorescent assay (IFA) Q fever IgM and IgG. Of 44 processed sera, 21 were seropositive. Specific IgM antibody was found in sera of 6 patients (19.4%), and specific IgG antibody in sera of 16 patients (51.2%). In sera of 15 clinically suspect patients (48.3%), no specific anticoxiella antibody was found. From these results we can confirm the importance of serology in laboratory diagnosis and clinical affirmation of suspect Q fever. Indirect imunofluorescent assay (IFA) is reliable and appropriate for daily, routine diagnosis of human Q fever.
Bartonella henselae and Borrelia burgdorferi Infections of the Central Nervous System
Authors: PODSIADLY EDYTA , CHMIELEWSKI TOMASZ , TYLEWSKA‐WIERZBANOWSKA STANISLAWA
Published: July 2009

Abstract: To investigate the role of B. henselae in patients with symptoms suggesting neuroborreliosis, serum and cerebrospinal fluid samples were tested with serological and PCR methods. Among 17 examined patients, in 12 cases Borrelia burgdorferi infections were detected, in 1 case Bartonella henselae infection was ascertained, and in two patients mixed B. burgdorferi and B. henselae infections were found. These results indicate that mixed infections should be taken into consideration in establishing diagnosis of neurological disorders. Further study of this conclusion is needed.
Wolbachia in the Inflammatory Pathogenesis of Human Filariasis
Authors: TAYLOR MARK J.
Published: July 2009

Abstract: Filarial nematodes cause some of the most debilitating diseases in tropical medicine. Recent studies, however, have implicated the parasites' endosymbiotic Wolbachia bacteria, rather than the nematode, as the cause of inflammatory‐mediated filarial disease. Soluble extracts of a variety of filarial species stimulate innate inflammatory responses, which are absent or reduced when using extracts derived from species either devoid of bacteria, or those cleared of bacteria by antibiotics. Characterization of the molecular nature of the bacterial derived inflammatory stimulus points toward an endotoxin‐like activity that is dependent on the pattern recognition receptors CD14 and TLR4 and can be inhibited by lipid A antagonists. TLR4 dependent inflammation has been shown to occur in the systemic inflammatory adverse reaction to Brugia malayi following anti‐filarial chemotherapy and in the development of neutrophil‐mediated ocular inflammation in a mouse model of river blindness. The development of acute and severe inflammatory responses in people infected with Brugia malayi and Onchocerca volvulus is associated with the release of Wolbachia into the blood following death or damage of the worms after anti‐filarial chemotherapy. Together these studies suggest that Wolbachia are the principal cause of acute inflammatory filarial disease. Accumulated exposure to acute episodes of inflammation may also underlie the development of chronic filarial pathology. The use of antibiotic therapy to target Wolbachia of filarial parasites may therefore provide a means to prevent the development of filarial pathology.