bluuebunny/crossref_metadata_2025 huggingface dataset:
DNA sequence data and morphology defineCryphonectriaspecies in Europe, China, and Japan
Authors: Myburg Henrietta , Gryzenhout Marieka , Wingfield Brenda D , Milgroom Michael G , Kaneko Shigeru , Wingfield Michael J
Published: January 2005

Cryphonectria includes important tree pathogens as well as species believed to be saprophytes. Recent phylogenetic studies have concentrated on North American and southern hemisphere Cryphonectria spp., but little is known about Asian and European taxa. In this study we identify and differentiate among the species occurring in Europe, China, and Japan using morphological and phylogenetic comparisons among the Cryphonectria species. Phylogenetic comparisons were based on sequence data from the ribosomal ITS operon and two regions in the β-tubulin gene. Unknown Japanese and Chinese isolates showing different cultural features than those of Cryphonectria parasitica (Murrill) M.E. Barr from Japan and the USA, grouped with isolates of Cryphonectria nitschkei (G.H. Otth) M.E. Barr from Quercus spp. and Rhus javanica L. Isolates of Cryphonectria havanensis (Bruner) M.E. Barr from Quercus grosseserrata Blume, Castanopsis cuspidata Schottky, Pyrus sinensis Lindl., and Eucalyptus globulus Labill. also grouped in this phylogenetic clade. We propose that Cryphonectria nitschkei and the fungus that has been referred to as Cryphonectria havanensis in Japan should be treated as a single taxon. Phylogenetic and morphological data also suggest that there are two species currently representing Cryphonectria radicalis (Schwein.: Fr.) M.E. Barr in Europe. One of these species is similar to the type specimen of Cryphonectria radicalis, while the other species probably is new.Key words: Cryphonectria parasitica, Cryphonectria radicalis, Cryphonectria havanensis, Cryphonectria macrospora, Cryphonectria nitschkei, Diaporthales.
Relations between air and surface temperature in discontinuous permafrost terrain near Mayo, Yukon Territory
Authors: Karunaratne K C , Burn C R
Published: January 2005

The association of site characteristics with the n-factor, a ratio of air to ground surface temperature, was investigated at five sites in the boreal forest near Mayo, Yukon Territory. Permafrost was in equilibrium with surface conditions at three sites, was degrading at another, and was absent from the fifth. Air and near-surface ground temperatures were recorded by data loggers between September 2000 and April 2002, and mean daily temperatures were accumulated to calculate n-factors for the freezing (nf) and thawing (nt) seasons. Air temperature did not vary between the sites, so inter-site differences in nf and nt were because of variations in surface temperature. Variations in nf between the sites over the two winters were primarily because of differences in snow depth, but at sites with similar snow cover, the surface temperatures were relatively high when the site was underlain by unfrozen ground. During summer, daily mean surface temperatures were initially less than air temperatures. However, once the thawing front had penetrated below the depth of diurnal temperature fluctuation, the air and ground surface temperatures converged. Since the rate of thaw penetration is governed by soil thermal diffusivity, nt varies directly with this property. These results indicate that subsurface conditions, particularly absolute temperature and ground thermal properties, exert considerable influence on n-factors, and, at the Mayo sites, the influence is greater than that of the vegetation.
Taconian mélanges in the parautochthonous zone of the Quebec Appalachians revisited: implications for foreland basin and thrust belt evolution
Authors: Comeau F -A , Kirkwood D , Malo M , Asselin E , Bertrand R
Published: January 2005

In the Quebec Appalachians, disruption, imbrication, and thrusting of the Taconian foreland basin sequence are responsible for the development of chaotic units within the turbiditic sequence of the Caradocian Sainte-Rosalie Group, the main lithologic assemblage of the parautochthonous zone. These chaotic units have been termed olistostromes or tectonosomes on the basis of field criteria and following Pini's (1999) classification. Olistostromal units containing blocks of the middle mudstone (Utica Shale) and upper turbidite units (Ste-Rosalie Group) of the foreland basin and spanning the Caradocian N. gracilis, C. americanus, O. ruedemanni, and C. spiniferus graptolite zones were deposited and incorporated into the Sainte-Rosalie Group. Disruption of more competent beds of the flyschic sequence and fault stacking and slicing of older rock units occurred along major thrust faults and now form structurally aligned corridors or tectonosomes. Graptolites and new chitinozoan data from both olistostromes and tectonosomes indicate older ages (early Late Ordovician) than the flysch units of Sainte-Rosalie Group (mid Late Ordovocian). Lithological, stratigraphic, and structural criteria indicate that tectonosome slices are imbricated foreland basin rocks that are correlative to the Black River, Trenton, Utica, Sainte-Rosalie, and Lorraine groups of the Laurentian platform. Thermal maturation data indicates that disruption of the autochthonous sequence, and folding and thrusting of the entire foreland basin sequence, must have occurred shortly after their deposition. Contrary to what had been suggested, blocks in the olistostromes and tectonosomes were not derived from the allochthonous Chaudière thrust sheet, even though it presently marks the southern contact with the parautochthonous zone. Imbrication of the foreland basin sequence must have occurred before emplacement of the Chaudière thrust sheet.
Structural controls on hypozonal orogenic gold mineralization in the La Ronge Domain, Trans-Hudson Orogen, Saskatchewan
Authors: Lafrance Bruno , Heaman Larry M
Published: January 2005

The La Ronge Domain is a granitegreenstone belt in the Saskatchewan segment of the ca. 1.91.8 Ga Trans-Hudson Orogen. The La Ronge volcanic arc was accreted to the Archean Hearne craton from ca. 1.87 to 1.86 Ga. Subduction of oceanic lithosphere beneath the accreted La Ronge  Hearne margin produced a voluminous suite of continental-arc intrusions. In the Waddy Lake area, the 1852.6 ± 1.5 Ma Corner Lake stock and 1859 ± 4 Ma and 1861 ± 2 Ma feldspar porphyry dykes crystallized from magmas generated from melting of the subducted oceanic slab. During the ca. 1.831.80 Trans-Hudson collision of the Hearne craton with the Archean Sask and Superior cratons, a penetrative regional foliation and a steeply plunging lineation formed within the La Ronge Domain. During further contraction across the domain, the deformation became localized in dextral and oblique-slip shear zones that generally follow contacts between more competent and less competent rock units. Orogenic gold mineralization is associated with quartz veins that are surrounded by hypozonal potassic and sulfidic alteration zones. The Komis gold deposit, the only past-producing gold mine in the Waddy Lake area, formed in the strain shadow of the Round Lake stock during the development of the regional foliation and lineation. Mineralization is associated with quartz veins that cut through tonalite dykes that behaved more brittlely than the surrounding metavolcanic rocks. The Golden Heart and Corner Lake gold deposits are hosted by south-side-up oblique-slip shear zones, which belong to a regional system of structures that extend from Saskatchewan to Manitoba.
Liquid-phase oxidation of benzene to phenol by copper catalysts in aqueous solvent with a high acetic acid concentration
Authors: Kitamura Takahiro , Kanzaki Hiroshi , Hamada Rei , Nishiyama Satoru , Tsuruya Shigeru
Published: January 2005

The liquid-phase catalytic oxidation of benzene was carried out under mild reaction conditions over Cu-impregnated zeolite catalysts (Cu/NaX, Cu/HX, Cu/NaY, Cu/HY, Cu/NaZSM-5, Cu/HZSM-5, Cu/Namordenite, Cu/Hmordenite, and Cu/Hbeta) using both molecular oxygen and ascorbic acid as the oxidant and the reducing reagents, respectively. Phenol was exclusively produced as the oxidation product and no other product was detected. Among the catalysts tested in this study, the Cu/HY catalyst had the highest activity for phenol formation. H-type zeolites were more effective supports for phenol formation than the corresponding Na-type ones. The yield of phenol was found to increase with the simultaneous increase in the amounts of both the supported Cu and the added ascorbic acid. The Cu species supported on HY began to elute as Cu2+ species in the solvent from the HY support with the initiation of the oxidation of benzene. The dissolved Cu2+ species were reduced to form precipitated Cu1+ species during the benzene oxidation. The homogeneous Cu species dissolved from the Cu/HY catalyst were thus suggested as mainly contributing to the phenol formation. The precipitated Cu1+ species that had no activity for the benzene oxidation were found to be regenerated in their oxidation activity toward phenol formation by calcination of the Cu1+ species in flowing air, although parts of the Cu species were found to be converted to aggregated CuO during the calcination.Key words: supported copper catalysts, zeolite, oxidation, benzene, phenol, oxygen, ascorbic acid.
2003 Fred Beamish Award Lecture  Exploring the dynamics of biological systems by mass spectrometry
Authors: Konermann Lars
Published: January 2005

This review describes the use of electrospray ionization mass spectrometry (ESI-MS) in conjunction with on-line rapid mixing techniques. This combination, termed "time-resolved" ESI-MS, provides a powerful approach for studying solution-phase reactions on timescales as short as a few milliseconds. Of particular interest is the application of this technique for monitoring protein folding reactions. Time-resolved ESI-MS can provide detailed information on structural changes of the polypeptide chain, while at the same time probing the occurrence of noncovalent ligandprotein interactions. Especially when used in combination with hydrogendeuterium pulse labeling, these measurements yield valuable structural information on short-lived folding intermediates. Similar approaches can be used to monitor the dynamics of proteins under equilibrium conditions. Another important application of time-resolved ESI-MS are mechanistic studies on enzyme-catalyzed processes. These reactions can be monitored under presteady-state conditions, without requiring artificial chromophoric substrates or radioactive labeling. We also discuss the use of ESI-MS for monitoring noncovalent ligandprotein interactions by diffusion measurements. In contrast to conventional MS-based techniques, this approach does not rely on the preservation of noncovalent interactions in the gas phase. It appears that diffusion measurements by ESI-MS could become an interesting alternative to existing methods for the high throughput screening of compound libraries in the context of drug discovery.Key words: reaction intermediate, rapid mixing, kinetics, protein conformation, protein function.
The chiral oxime of 13H-dibenzo(a,i)fluoren-13-one
Authors: Higgins Sean , Morris David G , Muir Kenneth W , Ryder Karl S
Published: January 2005

On the basis of single crystal diffraction analyses it is shown that conversion of 13H-dibenzo(a,i)fluoren-13-one into its oxime causes distortion of the aromatic framework because of steric crowding. The oxime is, in consequence, chiral.Key words: oxime, crystal structure, chirality.
Syntheses and electropolymerization behavior of ethylenedioxythiophene-substituted silanes
Authors: Chahma M'hamed , Hicks Robin G
Published: January 2005

Silicon-bridged thiophene oligomers have been prepared via the reactions of lithiated (3,4-ethylenedioxy)thiophene (EDOT) (1) or 2,2′-bis-(3,4-ethylenedioxy)thiophene (biEDOT) (2) with dichlorodimethylsilane to afford bis-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-5-yl)-dimethylsilane (3) and dimethyl-bis-(2,3,2′,3′-tetrahydro-[5,5′]bi[thieno[3,4-b] [1,4]dioxinyl]-7-yl)silane (4). Products 3 and 4 were characterized and show good stability in organic solvent and in air. The electropolymerization of these monomers affords stable and highly conducting polymers. The conductivity was found to be 25 and 60 S/cm for Poly3 and Poly4, respectively. Characterization data for the polymers suggested that the resulting materials have a backbone identical to p(EDOT), which formed through cleavage of the siliconcarbon (SiC) bonds during electropolymerization.Key words: polythiophenes, EDOT, silicon, electropolymerization, SiC bond cleavage, conductivity.
CALCIUM OXALATE IN PLANTS: Formation and Function
Authors: Franceschi Vincent R. , Nakata Paul A.
Published: January 2005

Calcium oxalate a highly insoluble crystalline salt of oxalic acid and calcium (CaOx) crystals are distributed among all taxonomic levels of photosynthetic organisms from small algae to angiosperms and giant gymnosperms. Accumulation of crystals by these organisms can be substantial. Major functions of CaOx crystal formation in plants include high-capacity calcium (Ca) regulation and protection against herbivory. Ultrastructural and developmental analyses have demonstrated that this biomineralization process is not a simple random physical-chemical precipitation of endogenously synthesized oxalic acid a strong and the simplest dicarboxylic acid, often thought of as a toxin or end product of metabolism, but which is also synthesized when calcium oxalate crystals are induced to form in plants and environmentally derived Ca. Instead, crystals are formed in specific shapes and sizes. Genetic regulation of CaOx formation is indicated by constancy of crystal morphology within species, cell specialization, and the remarkable coordination of crystal growth and cell expansion. Using a variety of approaches, researchers have begun to unravel the exquisite control mechanisms exerted by cells specialized for CaOx formation that include the machinery for uptake and accumulation of Ca, oxalic acid biosynthetic pathways, and regulation of crystal growth.
Use of EPR Power Saturation to Analyze the Membrane-Docking Geometries of Peripheral Proteins: Applications to C2 Domains
Authors: Malmberg Nathan J. , Falke Joseph J.
Published: January 2005

▪ Abstract  Despite the central importance of peripheral membrane proteins to cellular signaling and metabolic pathways, the structures of protein-membrane interfaces remain largely inaccessible to high-resolution structural methods. In recent years a number of laboratories have contributed to the development of an electron paramagnetic resonance (EPR) power saturation approach that utilizes site-directed spin labeling to determine the key geometric parameters of membrane-docked proteins, including their penetration depths and angular orientations relative to the membrane surface. Representative applications to Ca2+-activated, membrane-docking C2 domains are described.
FEATHERED DINOSAURS
Authors: Norell Mark A. , Xu Xing
Published: January 2005

▪ Abstract  Recent fossil discoveries from Early Cretaceous rocks of Liaoning Province, China, have provided a wealth of spectacular specimens. Included in these are the remains of several different kinds of small theropod dinosaurs, many of which are extremely closely related to modern birds. Unique preservation conditions allowed soft tissues of some of these specimens to be preserved. Many dinosaur specimens that preserve feathers and other types of integumentary coverings have been recovered. These fossils show a progression of integumentary types from simple fibers to feathers of modern aspect. The distribution of these features on the bodies of these animals is surprising in that some show large tail plumes, whereas others show the presence of wing-like structures on both fore and hind limbs. The phylogenetic distribution of feather types is highly congruent with models of feather evolution developed from developmental biology.
THE EDIACARA BIOTA: Neoproterozoic Origin of Animals and Their Ecosystems
Authors: Narbonne Guy M.
Published: January 2005

▪ Abstract  The Ediacara biota (575–542 Ma) marks the first appearance of large, architecturally complex organisms in Earth history. Present evidence suggests that the Ediacara biota included a mixture of stem- and crown-group radial animals, stem-group bilaterian animals, “failed experiments” in animal evolution, and perhaps representatives of other eukaryotic kingdoms. These soft-bodied organisms were preserved under (or rarely within) event beds of sand or volcanic ash, and four distinct preservational styles (Flinders-, Fermeuse-, Conception-, and Nama-style) profoundly affected the types of organisms and features that could be preserved. Even the earliest Ediacaran communities (575–565 Ma) show vertical and lateral niche subdivision of the sessile, benthic, filter-feeding organisms, which is strikingly like that of Phanerozoic and modern communities. Later biological and ecological innovations include mobility (>555 Ma), calcification (550 Ma), and predation (<549 Ma). The Ediacara biota abruptly disappeared 542 million years ago, probably as a consequence of mass extinction andor biological interactions with the rapidly evolving animals of the Cambrian explosion.
EVOLUTION OF FISH-SHAPED REPTILES (REPTILIA: ICHTHYOPTERYGIA) IN THEIR PHYSICAL ENVIRONMENTS AND CONSTRAINTS
Authors: Motani Ryosuke
Published: January 2005

▪ Abstract  Ichthyosaurs were a group of Mesozoic marine reptiles that evolved fish-shaped body outlines. They are unique in several anatomical characters, including the possession of enormous eyeballs sometimes exceeding 25 cm and an enlarged manus with sometimes up to 20 bones in a single digit, or 10 digits per manus. They are also unique in that their biology has been studied from the perspective of physical constraints, which allowed estimation of such characteristics as optimal cruising speed, visual sensitivity, and even possible basal metabolic rate ranges. These functional inferences, although based on physical principles, obviously contain errors arising from the limitations of fossilized data, but are necessarily stronger than the commonly made inferences based on superficial correlations among quantities without mechanical or optical explanations for why such correlations exist.
TURBULENT MIXING
Authors: Dimotakis Paul E.
Published: January 2005

▪ Abstract  The ability of turbulent flows to effectively mix entrained fluids to a molecular scale is a vital part of the dynamics of such flows, with wide-ranging consequences in nature and engineering. It is a considerable experimental, theoretical, modeling, and computational challenge to capture and represent turbulent mixing which, for high Reynolds number (Re) flows, occurs across a spectrum of scales of considerable span. This consideration alone places high-Re mixing phenomena beyond the reach of direct simulation, especially in high Schmidt number fluids, such as water, in which species diffusion scales are one and a half orders of magnitude smaller than the smallest flow scales. The discussion below attempts to provide an overview of turbulent mixing; the attendant experimental, theoretical, and computational challenges; and suggests possible future directions for progress in this important field.
MICROCIRCULATION AND HEMORHEOLOGY
Authors: Popel Aleksander S. , Johnson Paul C.
Published: January 2005

▪ Abstract  We review major experimental and theoretical studies on microcirculation and hemorheology, focusing on mechanics of blood flow and the vascular wall. We discuss flow of the blood formed elements [red blood cells (RBCs), white blood cells or leukocytes (WBCs) and platelets] in individual arterioles, capillaries, and venules, and in microvascular networks. We also review mechanical and rheological properties of the formed elements and their interactions with the vascular wall. We discuss short-term and long-term regulation of the microvasculature; the modes of regulation include metabolic, myogenic, and shear-stress-dependent mechanisms as well as vascular adaptation such as angiogenesis and vascular remodeling.
BLADEROW INTERACTIONS, TRANSITION, AND HIGH-LIFT AEROFOILS IN LOW-PRESSURE TURBINES
Authors: Hodson Howard P. , Howell Robert J.
Published: January 2005

▪ Abstract  The flow in turbomachines is unsteady due to the relative motion of the rows of blades. In the low-pressure turbine, the wakes from the upstream bladerows provide the dominant source of unsteadiness. Because much of the blade-surface boundary-layer flow is laminar, one of the most important consequences of this unsteadiness is the interaction of the wakes with the suction-side boundary layer of a downstream blade. This is important because the blade suction–side boundary layers are responsible for most of the loss of efficiency and because the combined effects of random (wake turbulence) and periodic disturbances (wake velocity defect and pressure fields) cause the otherwise laminar boundary layer to undergo transition and eventually become turbulent. This article summarizes the process of wake-induced boundary-layer transition in low-pressure turbines and the loss generation processes that result. Particular emphasis is placed on how the effects of wakes may be exploited to control loss generation and how this has enabled successful development of ultra-high-lift low-pressure turbines.
THE PHYSICS OF TROPICAL CYCLONE MOTION
Authors: Chan Johnny C.L.
Published: January 2005

▪ Abstract  This article reviews our current understanding of the physical mechanisms governing the movement of a tropical cyclone. In a barotropic framework, a tropical cyclone is basically “steered” by the surrounding flow but its movement is modified by the Coriolis force (referred to as the beta effect) and the horizontal vorticity gradient of the surrounding flow. In the presence of vertical wind shear and latent heat release, a tropical cyclone tends to move toward an area with a maximum in the time tendency of potential vorticity, which is mainly contributed by two processes: (a) advection that depends on the structures of the vortex and the environment surrounding the vortex in terms of their flow speed and vorticity gradient (including the beta effect), and (b) heating that results from a coupling between the latent heat released in the clouds and the vertical wind shear.
STRATOSPHERIC DYNAMICS
Authors: Haynes Peter
Published: January 2005

▪ Abstract  The large-scale dynamics of the extratropical stratosphere are reviewed. The role of Rossby waves and vortex dynamics in shaping the winter stratospheric circulation and the dynamics of the longitudinal mean flow are first discussed separately. The important effects of two-way interaction between waves and mean flow are then described, with emphasis on how mechanisms discovered in simple models can be followed through to models that are closer to the real stratosphere. A final topic is the possible effect of the stratosphere on the troposphere, with emphasis on dynamical mechanisms for such an effect.
MODELING FLUID FLOW IN OIL RESERVOIRS
Authors: Gerritsen Margot G. , Durlofsky Louis J.
Published: January 2005

▪ Abstract  Efficiently and accurately solving the equations governing fluid flow in oil reservoirs is very challenging because of the complex geological environment and the intricate properties of crude oil and gas at high pressure. We present these challenges and review successful and promising solution approaches. We discuss in detail the modeling of fluid flow in reservoirs with strongly varying rock properties. This requires subgrid-scale models that accurately represent the flow physics due to fine-scale fluctuations. A second focus is on the complex multiphase, multicomponent systems that describe miscible gas injection processes for enhanced oil recovery and CO2 sequestration.
GRAVITY-DRIVEN BUBBLY FLOWS
Authors: Mudde Robert F.
Published: January 2005

▪ Abstract  Gravity-driven bubbly flows are a specific class of flows, where all action is provided by gravity. An industrial example is formed by the so-called bubble column: a vertical cylinder filled with liquid through which bubbles flow that are introduced at the bottom of the cylinder. On the bubble scale, gravity gives rise to buoyancy of individual bubbles. On larger scales, gravity acts on nonuniformities in the spatial bubble distribution present in the bubbly mixture. The gravity-induced flow and flow structures can increase the inhomogeneity of the bubble distribution, leading to a turbulent flow. In this flow, specific scales are identified: a large-scale circulation with the liquid flowing upward in the center of the column and downward close to the wall. On the intermediate scale there are vortical structures; eddies of liquid, with a size on the order of the diameter of the column, that stir the liquid and radially transport the bubbles. On the small scale there is the local stirring of the bubbles. We describe the ideas developed over time and identify some open questions. We discuss the experimental findings on the turbulence generated, the stability of the flow, axial dispersion, and the similarities between bubble columns and air lifts. Especially for higher gas fractions, many questions still lack accurate answers. The lateral lift force in bubble swarms and the structure of the turbulence in the bubbly mixture are important examples of inadequately understood physical phenomena, providing many challenges for fundamental and applied research on bubbly flows.
Mixed muscle and hepatic derived plasma protein metabolism is differentially regulated in older and younger men following resistance exercise
Authors: Sheffield-Moore M. , Paddon-Jones D. , Sanford A. P. , Rosenblatt J. I. , Matlock A. G. , Cree M. G. , Wolfe R. R.
Published: January 2005

We sought to determine whether exercise-induced muscle protein turnover alters the subsequent production of hepatically derived acute-phase plasma proteins, and whether age affects how these proteins are regulated. We measured arteriovenous (a-v) balance and the synthesis of mixed muscle protein, albumin (A) and fibrinogen (F) before exercise (REST) and from the beginning of exercise to 10, 60, and 180 min following a single bout of moderate-intensity leg extension exercise (POST-EX) in postabsorptive untrained older ( n = 6) and younger ( n = 6) men using l-[ ring-2H5]phenylalanine (Phe). Subjects performed 6 sets of 8 repetitions of leg extension at 80% of their 1-RM (one-repetition maximum). All data are presented as the difference from REST (Δ from REST at 10, 60, and 180 min POST-EX). Mixed muscle fractional synthesis rate (FSR-M) increased significantly from the beginning of exercise until 10 min POST-EX in the older men (ΔFSR-M: 0.044%/h), whereas FSR-M in the younger men was not elevated until 180 min POST-EX (ΔFSR-M: 0.030%/h). FSR-A and FSR-F increased at all POST-EX periods in the older men (ΔFSR-A = 10 min: 1.90%/day; 60 min: 2.72%/day; 180 min: 2.78%/day; ΔFSR-F = 10 min: 1.00%/day; 60 min: 3.01%/day; 180 min: 3.73%/day). No change occurred in FSR-A in the younger men, but FSR-F was elevated from the beginning of exercise until 10 and 180 min POST-EX (10 min: 3.07%/day and 180 min: 3.96%/day). Net balance of Phe was positive in the older men in the immediate POST-EX period. Our data indicate that mixed muscle and hepatic derived protein synthesis is differentially regulated in younger and older men in response to a single bout of moderate-intensity leg extension exercise. Moreover, our data suggest that with age may come a greater need to salvage or make available amino acids from exercise-induced muscle protein breakdown to mount an acute-phase response.
Long-chain acyl-CoA esters inhibit phosphorylation of AMP-activated protein kinase at threonine-172 by LKB1/STRAD/MO25
Authors: Taylor E. B. , Ellingson W. J. , Lamb J. D. , Chesser D. G. , Winder W. W.
Published: January 2005

Activation of the AMP-activated protein kinase (AMPK) results in acute changes in cellular metabolism and transcriptional events that make the cell more robust when encountering an energy challenge. AMPK is thought to be inhibited by glycogen, the major storage form of intracellular carbohydrate. We hypothesized that long-chain acyl-CoA esters (LCACEs) might also inhibit AMPK signaling. Cytosolic LCACEs are available for immediate transport and oxidation within the mitochondria and accordingly may be representative of the lipid energy charge of the cell. We found that LCACEs inhibited phosphorylation of AMPK by the recombinant AMPK kinase (AMPKK) LKB1/STRAD/MO25 in a concentration-dependent manner. Palmitoyl-CoA (PCoA) did not affect the activity of phosphothreonine-172 AMPK. PCoA potently inhibited AMPKK purified from liver. Conversely, PCoA stimulated the kinase activity of LKB1/STRAD/MO25 toward the peptide substrate LKB1tide. Octanoyl-CoA, palmitate, and palmitoylcarnitine did not inhibit AMPKK activity. Removal of AMP from the reaction mixture resulted in reduced AMPKK activity in the presence of PCoA. In conclusion, these results demonstrate that the AMPKK activity of LKB1/STRAD/MO25 is substrate specific and distinct from the kinase activity of LKB1/STRAD/MO25 toward the peptide substrate LKB1tide. They also demonstrate that LCACEs inhibit the AMPKK activity of LKB1/STRAD/MO25 in a specific manner with a dependence on both a long fatty chain and a CoA moiety. These results suggest that the AMPK signaling cascade may directly sense and respond to the lipid energy charge of the cell.
Hyperhomocysteinemia induces hepatic cholesterol biosynthesis and lipid accumulation via activation of transcription factors
Authors: Woo Connie W. H. , Siow Yaw L. , Pierce Grant N. , Choy Patrick C. , Minuk Gerald Y. , Mymin David , O Karmin
Published: January 2005

Hyperhomocysteinemia is an independent risk factor for cardiovascular disorders. Elevated plasma homocysteine (Hcy) concentration is associated with other cardiovascular risk factors. We previously reported that Hcy stimulated cholesterol biosynthesis in HepG2 cells. In the present study, we investigated the underlying mechanisms of Hcy-induced hepatic cholesterol biosynthesis in an animal model. Hyperhomocysteinemia was induced in Sprague-Dawley rats by feeding a high-methionine diet for 4 wk. The mRNA expression and the enzyme activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase were significantly increased in livers of hyperhomocysteinemic rats. There were marked hepatic lipid accumulation and an elevation of plasma cholesterol concentration in hyperhomocysteinemic rats. Three transcription factors, namely, sterol regulatory element-binding protein-2 (SREBP-2), cAMP response element-binding protein (CREB), and nuclear factor Y (NF-Y) were activated in livers of hyperhomocysteinemic rats. Upon Hcy treatment of hepatocytes, there was a significant increase in HMG-CoA reductase mRNA expression in these cells. The activation of SREBP-2, CREB, and NF-Y preceded the increase in HMG-CoA reductase expression in Hcy-treated cells. Pretreatment of hepatocytes with inhibitors for transcription factors not only blocked the activation of SREBP-2, CREB, and NF-Y but also attenuated Hcy-induced HMG-CoA reductase mRNA expression. These results suggested that hyperhomocysteinemia-induced activation of SREBP-2, CREB, and NF-Y was responsible for increased cholesterol biosynthesis by transcriptionally regulating HMG-CoA reductase expression in the liver leading to hepatic lipid accumulation and subsequently hypercholesterolemia. In conclusion, the stimulatory effect of Hcy on hepatic cholesterol biosynthesis may represent an important mechanism for hepatic lipid accumulation and cardiovascular disorder associated with hyperhomocysteinemia.
Immunoregulatory effects of regulated, lung-targeted expression of IL-10 in vivo
Authors: Spight Donn , Zhao Bin , Haas Michael , Wert Susan , Denenberg Alvin , Shanley Thomas P.
Published: January 2005

Regulation of pulmonary inflammation involves an intricate balance of both pro- and anti-inflammatory mediators. Acute lung injury can result from direct pulmonary insults that activate alveolar macrophages to respond with increased cytokine expression. Such cytokine gene expression is mediated in part via NF-κB. IL-10 has been previously identified as an important endogenous anti-inflammatory cytokine in vivo on the basis of inhibiting NF-κB activation; however, the mechanism of this inhibition remains incompletely defined. We hypothesized that IL-10 regulated NF-κB activation in vivo via IκK inhibition. A bitransgenic mouse that allowed for externally regulated, lung-specific human IL-10 overexpression was generated. In the bitransgenic mice, introduction of doxycycline induced lung-specific, human IL-10 overexpression. Acute induction of IL-10 resulted in significant decreases in bronchoalveolar lavage fluid neutrophils (48%, P = 0.03) and TNF (62%, P < 0.01) following intratracheal LPS compared with bitransgenic negative mice. In vitro kinase assays showed this decrease to correlate to diminished lung IκK activity. Furthermore, we also examined the effect of chronic IL-10 overexpression in these transgenic mice. Results show that IL-10 overexpression in lungs of mature mice increased the number of intrapulmonary cells the phenotype of which was skewed toward increased B220+/CD45+ B cells and CD4+ T cells and was associated with increased CC chemokine expression. Thus regulated, lung-specific IL-10 overexpression may have a variety of complex immunologic effects depending on the timing and duration of expression.
Abrogation of apoptosis through PDGF-BB-induced sulfated glycosaminoglycan synthesis and secretion
Authors: Cartel Nicholas J. , Post Martin
Published: January 2005

Platelet-derived growth factor (PDGF)-BB-stimulated glycosaminoglycan (GAG) synthesis/secretion in fetal lung fibroblasts is dependent on sequential activation of the PDGF β-receptor, phosphatidylinositol 3-kinase (PI3K), the serine/threonine kinase Akt-1,2, and the GTPase Rab3D. Because the Akt pathway has been implicated in cell survival mechanisms, we investigated whether the pathway regulating GAG synthesis/secretion was antiapoptotic. PDGF-BB treatment protected fetal lung fibroblasts against serum starvation-induced apoptosis, whereas wortmannin, an inhibitor of PI3K, abrogated this protective effect. Transfection of constitutively active Akt into fetal lung fibroblasts also safeguarded the cells from apoptosis induced by serum starvation. To determine whether the antiapoptotic response was due, at least in part, to GAGs, we treated lung fibroblasts with β-d-xyloside as well as with topically applied GAGs, specifically those produced by fetal lung fibroblasts. β-d-xyloside increased GAG synthesis/secretion and diminished apoptosis. Application of sulfated GAGs, chondroitin sulfate, and heparan sulfate, but not nonsulfated hyaluronan, also resulted in diminished apoptosis. Moreover, topically applied sulfated GAGs increased Bcl-associated death promoter phosphorylation and diminished caspase-3 and -7 cleavage, indicating an antiapototic response. These data are compatible with the PDGF-BB-GAG signaling pathway regulating programmed fibroblast death in the fetal lung.
Neutrophil elastase activates near-silent epithelial Na+channels and increases airway epithelial Na+transport
Authors: Caldwell Ray A. , Boucher Richard C. , Stutts M. Jackson
Published: January 2005

Neutrophil elastase is a serine protease that is abundant in the airways of individuals with cystic fibrosis (CF), a genetic disease manifested by excessive airway Na+absorption and consequent depletion of the airway surface liquid layer. Although endogenous epithelium-derived serine proteases regulate epithelial Na+transport, the effects of neutrophil elastase on epithelial Na+transport and epithelial Na+channel (ENaC) activity are unknown. Low micromolar concentrations of human neutrophil elastase (hNE) applied to the apical surface of a human bronchial cell line (16HBE14o-/βγ) increased Na+transport about twofold. Similar effects were observed with trypsin, also a serine protease. Proteolytic inhibitors of hNE or trypsin selectively abolished the enzyme-induced increase of epithelial Na+transport. At the level of the single channel, submicromolar concentrations of hNE increased activity of near-silent ENaC ∼108-fold in patches from NIH-3T3 cells expressing rat α-, β-, and γ-ENaC subunits. However, no enzyme effects were observed on basally active ENaCs. Trypsin exposure following hNE revealed no additional increase in amiloride-sensitive short-circuit current or in ENaC activity, suggesting these enzymes share a common mode of action for increasing Na+transport, likely through proteolytic activation of ENaC. The hNE-induced increase of near-silent ENaC activity in CF airways could contribute to Na+hyperabsorption, reduced airway surface liquid height, and dehydrated mucus culminating in inefficient mucociliary clearance.
Substitution of chromosome 1 amelioratesl-NAME hypertension and renal disease in the fawn-hooded hypertensive rat
Authors: Mattson David L. , Kunert Mary Pat , Roman Richard J. , Jacob Howard J. , Cowley Allen W.
Published: January 2005

Linkage analysis studies previously identified genetic loci associated with proteinuria and hypertension on chromosome 1 of fawn-hooded hypertensive (FHH) rats. The present studies were performed on conscious male and female rats to evaluate the influence of transfer of chromosome 1 from the Brown Norway (BN) rat to the FHH genetic background (FHH-1BN). Rats were maintained for 2 wk on 8.0% NaCl chow with NG-nitro-l-arginine methyl ester (l-NAME) in the drinking water (12.5 mg/l) to induce hypertension and accelerate the onset of renal disease. Mean arterial blood pressure (MAP) was significantly higher in the male FHH (188 ± 3 mmHg, n = 13) compared with the BN (121 ± 3 mmHg, n = 8); MAP in the FHH-1BNwas midway between the two parental strains (167 ± 5 mmHg, n = 9). Urinary protein and albumin excretion rates in the male FHH-1BN(Uprot = 189 ± 36 mg/day, Ualb = 69 ± 16 mg/day, n = 10) were also midway between levels observed in the FHH (Uprot = 485 ± 54 mg/day; Ualb = 206 ± 25 mg/day, n = 13) and the BN (Uprot = 32 ± 5 mg/day, Ualb = 5 ± 1 mg/day, n = 8). Creatinine clearance was elevated, and the degree of glomerular damage was significantly reduced in the FHH-1BNcompared with the FHH. Qualitatively similar results were obtained from female FHH, FHH-1BN, and BN rats. The present results indicate that genes contributing to l-NAME-induced hypertension and renal disease are found on chromosome 1 of the FHH rat.
3He MRI-based assessment of posture-dependent regional ventilation gradients in rats
Authors: Månsson Sven , Deninger Anselm J. , Magnusson Peter , Pettersson Göran , Olsson Lars E. , Hansson Georg , Wollmer Per , Golman Klaes
Published: January 2005

A recently developed method for quantitative assessment of regional lung ventilation was employed for the study of posture-dependent ventilation differences in rats. The measurement employed hyperpolarized 3He MRI to detect the build-up of the signal intensity after increasing numbers of 3He breaths, which allowed for computation of a regional ventilation parameter. A group of six anesthetized rats was studied in both supine and prone postures. Three-dimensional maps of the ventilation parameter were obtained with high spatial resolution (voxel volume ∼2 mm3). Vertical (dorsal-ventral) gradients of the ventilation index, defined as the regional ventilation normalized by the average ventilation within the whole lung, were investigated. Variations in the regional distribution of the ventilation parameter, as well as of the ventilation index, could be detected, depending on the posture of the rats. In supine posture, ventilation was elevated in the dependent parts of the lungs, with a linear gradient of the ventilation index of −0.11 ± 0.03 cm−1. In prone posture, the distribution of ventilation was more uniform, with a significantly ( P < 0.001) smaller gradient of the ventilation index of −0.01 ± 0.02 cm−1. It is concluded that the 3He MRI-based method can detect and quantify regional ventilation gradients in animals as small as the rat and that these gradients depend on prone or supine posture of the animal.
Pilocarpine-induced sweat gland function in individuals with multiple sclerosis
Authors: Davis Scott L. , Wilson Thad E. , Vener Jamie M. , Crandall Craig G. , Petajan Jack H. , White Andrea T.
Published: January 2005

This investigation tested the hypothesis that cholinergic sweat function of individuals with multiple sclerosis (MS) (MS-Con; n = 10) is diminished relative to matched healthy control subjects (Con; n = 10). In addition, cholinergic sweat function was determined before and after 15 wk of aerobic training in a subgroup of individuals with MS (MS-Ex; n = 7). Cholinergic sweating responses were assessed via pilocarpine iontophoresis on ventral forearm skin. A collection disk placed over the stimulated area collected sweat for 15 min. Sweat rate (SR) was calculated by dividing sweat collector volume by collection area and time. Iodine-treated paper was applied to the stimulated area to measure number of activated sweat glands (ASG). Sweat gland output (SGO) was calculated by dividing SR by density of glands under the collector. Sweat gland function was determined in MS-Ex to test the hypothesis that exercise training would increase sweating responses. No differences in ASG were observed between MS-Con and Con. SR and SGO in MS-Con [0.18 mg·cm−2·min−1(SD 0.08); 1.74 μg·gland−1·min−1(SD 0.79), respectively] were significantly lower ( P ≤ 0.05) than in Con [0.27 mg·cm−2·min−1(SD 0.10); 2.43 μg·gland−1·min−1(SD 0.69)]. Aerobic exercise training significantly ( P ≤ 0.05) increased peak aerobic capacity in MS-Ex [1.86 (SD 0.75) vs. 2.10 (SD 0.67) l/min] with no changes in ASG, SR, and SGO. Sweat gland function in individuals with MS is impaired relative to healthy controls. Fifteen weeks of aerobic training did not increase stimulated sweating responses in individuals with MS. Diminished peripheral sweating responses may be a consequence of impairments in autonomic control of sudomotor function.
Albuterol aids resistance exercise in reducing unloading-induced ankle extensor strength losses
Authors: Caruso John , Hamill John , Yamauchi Miki , Mercado Dean , Cook Tim , Higginson Brian , O'Meara Sean , Elias Jeff , Siconolfi Steve
Published: January 2005

While resistance exercise (REX) reduces ankle extensor (AE) mass and strength deficits during short-term unloading; additional treatments, concurrently administered with REX, are required to attenuate the greater losses seen with longer unloading periods. Subjects performed left leg REX, which otherwise refrained from ambulatory and weight-bearing activity for 40 days, while randomized to a capsule (placebo, albuterol) dosing regimen with no crossover to note whether albuterol helps REX mitigate unloading-induced AE losses. A third group of subjects served as unloaded controls. On days 0, 20, and 40, the following data were collected from the left leg: calf cross-sectional area and AE strength measures. Cross-sectional area was estimated using anthropometric methodology, whereas AE strength data were obtained from eight unilateral calf-press repetitions on an inertial-based REX device. Repeated-measures mixed-factorial 3 × 3 analyses of covariance, with day 0 values as a covariate, revealed group × time interactions for the strength variables eccentric total work (ETW) and average power (EAP). Tukey's honestly significant difference shows REX-placebo subjects incurred significant ETW and EAP losses by day 40, whereas the REX-albuterol treatment evoked strength gains to those same variables without concurrent muscle accretion. Corresponding concentric variables did not display similar changes. Day 40 control data significantly declined for many variables; relative to the REX-albuterol treatment, some losses were significant after 20 days. ETW and EAP gains to unloaded AE may be due to one or more mechanisms. Continued research identifying mechanisms responsible for such changes, as well as the safety of REX-albuterol administration in other models, is warranted.
Superoxide scavengers augment contractile but not energetic responses to hypoxia in rat diaphragm
Authors: Wright V. P. , Klawitter P. F. , Iscru D. F. , Merola A. J. , Clanton T. L.
Published: January 2005

Acute exposure to severe hypoxia depresses contractile function and induces adaptations in skeletal muscle that are only partially understood. Previous studies have demonstrated that antioxidants (AOXs) given during hypoxia partially protect contractile function, but this has not been a universal finding. This study confirms that specific AOXs, known to act primarily as superoxide scavengers, protect contractile function in severe hypoxia. Furthermore, the hypothesis is tested that the mechanism of protection involves preservation of high-energy phosphates (ATP, creatine phosphate) and reductions of Pi. Rat diaphragm muscle strips were treated with AOXs and subjected to 30 min of hypoxia. Contractile function was examined by using twitch and tetanic stimulations and the degree of elevation in passive force occurring during hypoxia (contracture). High-energy phosphates were measured at the end of 30-min hypoxia exposure. Treatment with the superoxide scavengers 4,5-dihydroxy-1,3-benzenedisulfonic acid (Tiron, 10 mM) or Mn(III)tetrakis(1-methyl-4-pyridyl) porphyrin pentachloride (50 μM) suppressed contracture during hypoxia and protected maximum tetanic force. N-acetylcysteine (10 or 18 mM) had no influence on tetanic force production. Contracture during hypoxia without AOXs was also shown to be dependent on the extracellular Ca2+concentration. Although hypoxia resulted in only small reductions in ATP concentration, creatine phosphate concentration was decreased to ∼10% of control. There were no consistent influences of the AOX treatments on high-energy phosphates during hypoxia. The results demonstrate that superoxide scavengers can protect contractile function and reduce contracture in hypoxia through a mechanism that does not involve preservation of high-energy phosphates.
Modulation of bone ingrowth of rabbit femur titanium implants by in vivo axial micromechanical loading
Authors: Clark Paul A. , Rodriguez Anthony , Sumner D. Rick , Hussain Mohammad A. , Mao Jeremy J.
Published: January 2005

Titanium implants commonly used in orthopedics and dentistry integrate into host bone by a complex and coordinated process. Despite increasingly well illustrated molecular healing processes, mechanical modulation of implant bone ingrowth is poorly understood. The objective of the present study was to determine whether micromechanical forces applied axially to titanium implants modulate bone ingrowth surrounding intraosseous titanium implants. We hypothesized that small doses of micromechanical forces delivered daily to the bone-implant interface enhance implant bone ingrowth. Small titanium implants were placed transcortically in the lateral aspect of the proximal femur in 15 New Zealand White rabbits under general anesthesia and allowed to integrate with the surrounding bone for 6 wk. Micromechanical forces at 200 mN and 1 Hz were delivered axially to the right femur implants for 10 min/day over 12 consecutive days, whereas the left femur implants served as controls. The average bone volume 1 mm from mechanically loaded implants ( n = 15) was 73 ± 12%, which was significantly greater than the average bone volume (52 ± 21%) of the contralateral controls ( n = 15) ( P < 0.01). The average number of osteoblast-like cells per endocortical bone surface was 55 ± 8 cells/mm2for mechanically loaded implants, which was significantly greater than the contralateral controls (35 ± 6 cells/mm2) ( P < 0.01). Dynamic histomorphometry showed a significant increase in mineral apposition rate and bone-formation rate of mechanically stressed implants (3.8 ± 1.2 μm/day and 2.4 ± 1.0 μm3·μm−2·day−1, respectively) than contralateral controls (2.2 ± 0.92 μm/day and 1.2 ± 0.60 μm3·μm−2·day−1, respectively; P < 0.01). Collectively, these data suggest that micromechanical forces delivered axially on intraosseous titanium implants may have anabolic effects on implant bone ingrowth.