bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Tylosin Use on Erythromycin Resistance in Enterococci Isolated from Swine
Authors: Jackson Charlene R. , Fedorka-Cray Paula J. , Barrett John B. , Ladely Scott R.
Published: July 2004

The effect of tylosin on erythromycin-resistant enterococci was examined on three farms; farm A used tylosin for growth promotion, farm B used tylosin for treatment of disease, and farm C did not use tylosin for either growth promotion or disease treatment. A total of 1,187 enterococci were isolated from gestation, farrowing, suckling, nursery, and finishing swine from the farms. From a subset of those isolates (
n
= 662), 59% (124 out of 208), 28% (80 out of 281), and 2% (4 out of 170) were resistant to erythromycin (MIC ≥ 8 μg/ml) from farms A, B, and C, respectively. PCR analysis and Southern blotting revealed that 95% (65 out of 68) of isolates chosen from all three farms for further study were positive for
ermB
, but all were negative for
ermA
and
ermC
. By using Southern blotting,
ermB
was localized to the chromosome in 56 of the isolates while 9 isolates from farms A and B contained
ermB
on two similar-sized plasmid bands (12 to 16 kb). Pulsed-field gel electrophoresis revealed that the isolates were genetically diverse and represented a heterogeneous population of enterococci. This study suggests that although there was resistance to a greater number of enterococcal isolates on a farm where tylosin was used as a growth promotant, resistant enterococci also existed on a farm where no antimicrobial agents were used.
Simultaneous Discrimination between 15 Fish Pathogens by Using 16S Ribosomal DNA PCR and DNA Microarrays
Authors: Warsen Adelaide E. , Krug Melissa J. , LaFrentz Stacey , Stanek Danielle R. , Loge Frank J. , Call Douglas R.
Published: July 2004

We developed a DNA microarray suitable for simultaneous detection and discrimination between multiple bacterial species based on 16S ribosomal DNA (rDNA) polymorphisms using glass slides. Microarray probes (22- to 31-mer oligonucleotides) were spotted onto Teflon-masked, epoxy-silane-derivatized glass slides using a robotic arrayer. PCR products (ca. 199 bp) were generated using biotinylated, universal primer sequences, and these products were hybridized overnight (55°C) to the microarray. Targets that annealed to microarray probes were detected using a combination of Tyramide Signal Amplification and Alexa Fluor 546. This methodology permitted 100% specificity for detection of 18 microbes, 15 of which were fish pathogens. With universal 16S rDNA PCR (limited to 28 cycles), detection sensitivity for purified control DNA was equivalent to <150 genomes (675 fg), and this sensitivity was not adversely impacted either by the presence of competing bacterial DNA (1.1 × 10
6
genomes; 5 ng) or by the addition of up to 500 ng of fish DNA. Consequently, coupling 16S rDNA PCR with a microarray detector appears suitable for diagnostic detection and surveillance for commercially important fish pathogens.
Osmotic Stress Response: Quantification of Cell Maintenance and Metabolic Fluxes in a Lysine-Overproducing Strain of
Corynebacterium glutamicum
Authors: Varela Cristian A. , Baez Mauricio E. , Agosin Eduardo
Published: July 2004

Osmotic
stress diminishes cell productivity and may cause cell
inactivation in industrial fermentations. The quantification of
metabolic changes under such conditions is fundamental for
understanding and describing microbial behavior during bioprocesses. We
quantified the gradual changes that take place when a
lysine-overproducing strain of
Corynebacterium glutamicum
is
grown in continuous culture with saline gradients at different dilution
rates. The use of compatible solutes depended on environmental
conditions; certain osmolites predominated at different dilution rates
and extracellular osmolalities. A metabolic flux analysis showed that
at high dilution rates
C. glutamicum
redistributed its
metabolic fluxes, favoring energy formation over growth. At low
dilution rates, cell metabolism accelerated as the osmolality was
steadily increased. Flexibility in the oxaloacetate node
proved to be key for the energetic redistribution that occurred when
cells were grown at high dilution rates. Substrate and ATP maintenance
coefficients increased 30- and 5-fold, respectively, when
the osmolality increased, which demonstrates that
energy pool management is fundamental for sustaining
viability.
Geomicrobiology of High-Level Nuclear Waste-Contaminated Vadose Sediments at the Hanford Site, Washington State
Authors: Fredrickson James K. , Zachara John M. , Balkwill David L. , Kennedy David , Li Shu-mei W. , Kostandarithes Heather M. , Daly Michael J. , Romine Margaret F. , Brockman Fred J.
Published: July 2004

Sediments from a high-level nuclear waste plume were collected as part of investigations to evaluate the potential fate and migration of contaminants in the subsurface. The plume originated from a leak that occurred in 1962 from a waste tank consisting of high concentrations of alkali, nitrate, aluminate, Cr(VI),
137
Cs, and
99
Tc. Investigations were initiated to determine the distribution of viable microorganisms in the vadose sediment samples, probe the phylogeny of cultivated and uncultivated members, and evaluate the ability of the cultivated organisms to survive acute doses of ionizing radiation. The populations of viable aerobic heterotrophic bacteria were generally low, from below detection to ∼10
4
CFU g
−1
, but viable microorganisms were recovered from 11 of 16 samples, including several of the most radioactive ones (e.g., >10 μCi of
137
Cs/g). The isolates from the contaminated sediments and clone libraries from sediment DNA extracts were dominated by members related to known gram-positive bacteria. Gram-positive bacteria most closely related to
Arthrobacter
species were the most common isolates among all samples, but other phyla high in G+C content were also represented, including
Rhodococcus
and
Nocardia
. Two isolates from the second-most radioactive sample (>20 μCi of
137
Cs g
−1
) were closely related to
Deinococcus radiodurans
and were able to survive acute doses of ionizing radiation approaching 20 kGy. Many of the gram-positive isolates were resistant to lower levels of gamma radiation. These results demonstrate that gram-positive bacteria, predominantly from phyla high in G+C content, are indigenous to Hanford vadose sediments and that some are effective at surviving the extreme physical and chemical stress associated with radioactive waste.
Natural Atypical
Listeria innocua
Strains with
Listeria monocytogenes
Pathogenicity Island 1 Genes
Authors: Johnson J. , Jinneman K. , Stelma G. , Smith B. G. , Lye D. , Messer J. , Ulaszek J. , Evsen L. , Gendel S. , Bennett R. W. , Swaminathan B. , Pruckler J. , Steigerwalt A. , Kathariou S. , Yildirim S. , Volokhov D. , Rasooly A. , Chizhikov V. , Wiedmann M. , Fortes E. , Duvall R. E. , Hitchins A. D.
Published: July 2004

Identification of bona fide
Listeria
isolates into the six species of the genus normally requires only a few tests. Aberrant isolates do occur, but even then only one or two extra confirmatory tests are generally needed for identification to species level. We have discovered a hemolytic-positive, rhamnose and xylose fermentation-negative
Listeria
strain with surprising recalcitrance to identification to the species level due to contradictory results in standard confirmatory tests. The issue had to be resolved by using total DNA-DNA hybridization testing and then confirmed by further specific PCR-based tests including a
Listeria
microarray assay. The results show that this isolate is indeed a novel one. Its discovery provides the first fully documented instance of a hemolytic
Listeria innocua
strain. This species, by definition, is typically nonhemolytic. The
L. innocua
isolate contains all the members of the PrfA-regulated virulence gene cluster (
Listeria
pathogenicity island 1) of
L. monocytogenes
. It is avirulent in the mouse pathogenicity test. Avirulence is likely at least partly due to the absence of the
L. monocytogenes
-specific allele of
iap
, as well as the absence of
inlA
,
inlB
,
inlC
, and
daaA
. At least two of the virulence cluster genes,
hly
and
plcA
, which encode the
L. monocytogenes
hemolysin (listeriolysin O) and inositol-specific phospholipase C, respectively, are phenotypically expressed in this
L. innocua
strain. The detection by PCR assays of specific
L. innocua
genes (
lin0198
,
lin0372
,
lin0419
,
lin0558
,
lin1068
,
lin1073
,
lin1074
,
lin2454
, and
lin2693
) and noncoding intergenic regions (
lin0454-lin0455
and
nadA-lin2134
) in the strain is consistent with its
L. innocua
DNA-DNA hybridization identity. Additional distinctly different hemolytic
L. innocua
strains were also studied.
Solar and Temporal Effects on
Escherichia coli
Concentration at a Lake Michigan Swimming Beach
Authors: Whitman Richard L. , Nevers Meredith B. , Korinek Ginger C. , Byappanahalli Muruleedhara N.
Published: July 2004

Studies on solar inactivation of
Escherichia coli
in freshwater and in situ have been limited. At 63rd St. Beach, Chicago, Ill., factors influencing the daily periodicity of culturable
E. coli
, particularly insolation, were examined. Water samples for
E. coli
analysis were collected twice daily between April and September 2000 three times a week along five transects in two depths of water. Hydrometeorological conditions were continuously logged: UV radiation, total insolation, wind speed and direction, wave height, and relative lake level. On 10 days, transects were sampled hourly from 0700 to 1500 h. The effect of sunlight on
E. coli
inactivation was evaluated with dark and transparent in situ mesocosms and ambient lake water. For the study, the number of
E. coli
samples collected (
n
) was 2,676. During sunny days,
E. coli
counts decreased exponentially with day length and exposure to insolation, but on cloudy days,
E. coli
inactivation was diminished; the
E. coli
decay rate was strongly influenced by initial concentration. In situ experiments confirmed that insolation primarily inactivated
E. coli
; UV radiation only marginally affected
E. coli
concentration. The relationship between insolation and
E. coli
density is complicated by relative lake level, wave height, and turbidity, all of which are often products of wind vector. Continuous importation and nighttime replenishment of
E. coli
were evident. These findings (i) suggest that solar inactivation is an important mechanism for natural reduction of indicator bacteria in large freshwater bodies and (ii) have implications for management strategies of nontidal waters and the use of
E. coli
as an indicator organism.
Metabolic Engineering of Mannitol Production inLactococcus lactis: Influence of Overexpression of Mannitol 1-Phosphate Dehydrogenase in Different Genetic Backgrounds
Authors: Wisselink H. Wouter , Mars Astrid E. , van der Meer Pieter , Eggink Gerrit , Hugenholtz Jeroen
Published: July 2004

To obtain a mannitol-producingLactococcus lactisstrain, the mannitol 1-phosphate dehydrogenase gene (mtlD) fromLactobacillus plantarumwas overexpressed in a wild-type strain, a lactate dehydrogenase(LDH)-deficient strain, and a strain with reduced phosphofructokinase activity. High-performance liquid chromatography and13C nuclear magnetic resonance analysis revealed that small amounts (<1%) of mannitol were formed by growing cells ofmtlD-overexpressing LDH-deficient and phosphofructokinase-reduced strains, whereas resting cells of the LDH-deficient transformant converted 25% of glucose into mannitol. Moreover, the formed mannitol was not reutilized upon glucose depletion. Of the metabolic-engineering strategies investigated in this work,mtlD-overexpressing LDH-deficientL. lactisseemed to be the most promising strain for mannitol production.
Detection of Genes Involved in Biodegradation and Biotransformation in Microbial Communities by Using 50-Mer Oligonucleotide Microarrays
Authors: Rhee Sung-Keun , Liu Xueduan , Wu Liyou , Chong Song C. , Wan Xiufeng , Zhou Jizhong
Published: July 2004

To effectively monitor biodegrading populations, a comprehensive 50-mer-based oligonucleotide microarray was developed based on most of the 2,402 known genes and pathways involved in biodegradation and metal resistance. This array contained 1,662 unique and group-specific probes with <85% similarity to their nontarget sequences. Based on artificial probes, our results showed that under hybridization conditions of 50°C and 50% formamide, the 50-mer microarray hybridization can differentiate sequences having <88% similarity. Specificity tests with representative pure cultures indicated that the designed probes on the arrays appeared to be specific to their corresponding target genes. The detection limit was ∼5 to 10 ng of genomic DNA in the absence of background DNA and 50 to 100 ng of pure-culture genomic DNA in the presence of background DNA or 1.3 × 10
7
cells in the presence of background RNA. Strong linear relationships between the signal intensity and the target DNA and RNA were observed (

r
2

= 0.95 to 0.99). Application of this type of microarray to analyze naphthalene-amended enrichment and soil microcosms demonstrated that microflora changed differently depending on the incubation conditions. While the naphthalene-degrading genes from
Rhodococcus
-type microorganisms were dominant in naphthalene-degrading enrichments, the genes involved in naphthalene (and polyaromatic hydrocarbon and nitrotoluene) degradation from gram-negative microorganisms, such as
Ralstonia
,
Comamonas
, and
Burkholderia
, were most abundant in the soil microcosms. In contrast to general conceptions, naphthalene-degrading genes from
Pseudomonas
were not detected, although
Pseudomonas
is widely known as a model microorganism for studying naphthalene degradation. The real-time PCR analysis with four representative genes showed that the microarray-based quantification was very consistent with real-time PCR (

r
2

= 0.74). In addition, application of the arrays to both polyaromatic-hydrocarbon- and benzene-toluene-ethylbenzene-xylene-contaminated and uncontaminated soils indicated that the developed microarrays appeared to be useful for profiling differences in microbial community structures. Our results indicate that this technology has potential as a specific, sensitive, and quantitative tool in revealing a comprehensive picture of the compositions of biodegradation genes and the microbial community in contaminated environments, although more work is needed to improve detection sensitivity.
Use of Fluorescent Lectin Probes for Analysis of Footprints from
Pseudomonas aeruginosa
MDC on Hydrophilic and Hydrophobic Glass Substrata
Authors: Bejarano Eduardo Mora , Schneider René Peter
Published: July 2004

Microbial footprints of
Pseudomonas aeruginosa
MDC attached for 1 h to clean or silanized glass were analyzed with fluorescently labeled lectin probes. Footprint composition varied, depending on cell physiology and substratum surface chemistry. This suggests that substratum physicochemistry affected the structure of cell surfaces of adsorbed organisms.
Genotyping of
Cryptosporidium
Isolates from
Chamelea gallina
Clams in Italy
Authors: Traversa Donato , Giangaspero Annunziata , Molini Umberto , Iorio Raffaella , Paoletti Barbara , Otranto Domenico , Giansante Carla
Published: July 2004

Chamelea gallina
clams collected from the mouths of rivers along the Adriatic Sea (central Italy) were found to harbor
Cryptosporidium parvum
(genotype 2), which is the lineage involved in zoonotic transmission. The clams were collected from the mouths of rivers near whose banks ruminants are brought to graze. This paper reports the environmental spread of
C. parvum
in Italy and highlights the fact that genotyping of seaborne
Cryptosporidium
isolates is a powerful tool with which to investigate the transmission patterns and epidemiology of this microorganism.
Combined Immunomagnetic Separation-Molecular Beacon-Reverse Transcription-PCR Assay for Detection of Hepatitis A Virus from Environmental Samples
Authors: Abd El Galil Khaled H. , El Sokkary M. A. , Kheira S. M. , Salazar Andre M. , Yates Marylynn V. , Chen Wilfred , Mulchandani Ashok
Published: July 2004

In this study, a molecular-beacon-based real-time reverse transcription (RT)-PCR assay was developed to detect the presence of hepatitis A virus (HAV) in environmental samples. A 125-bp, highly conserved 5′ noncoding region of HAV was targeted. The sensitivity of the real-time RT-PCR assay was tested with 10-fold dilutions of viral RNA, and a detection limit of 1 PFU was obtained. The specificity of the assay was demonstrated by testing with other environmental pathogens and indicator microorganisms, and only HAV was positively identified. When combined with immunomagnetic separation, the real-time RT-PCR assay successfully detected as few as 20 PFU in seeded groundwater samples. Because of its simplicity and specificity, this assay has broad applications for the rapid detection of HAV in contaminated foods or water.
Evidence for Acyl Homoserine Lactone Signal Production in Bacteria Associated with Marine Sponges
Authors: Taylor Michael W. , Schupp Peter J. , Baillie Harriet J. , Charlton Timothy S. , de Nys Rocky , Kjelleberg Staffan , Steinberg Peter D.
Published: July 2004

We report for the first time the production of acyl homoserine lactones (AHLs) by bacteria associated with marine sponges. Given the involvement of AHLs in bacterial colonization of many higher organisms, we speculate that such quorum sensing signals could play a part in interactions between sponges and the dense bacterial communities living within them.
Online Tool for Analysis of Denaturing Gradient Gel Electrophoresis Profiles
Authors: Huber Florian , Peduzzi Peter
Published: July 2004

We
present an online tool (EquiBands,
http://www.univie.ac.at/IECB/limno/equibands/EquiBands.html
)
that quantifies the matching of two bands considered to be the same in
different samples, even when samples are applied to different
denaturing gradient gel electrophoresis gels. With an environmental
example we demonstrate the procedure for the classification of two
bands of different samples with the help of
EquiBands.
Degradation of Alkyl Ethers, Aralkyl Ethers, and Dibenzyl Ether by
Rhodococcus
sp. Strain DEE5151, Isolated from Diethyl Ether-Containing Enrichment Cultures
Authors: Kim Yong-Hak , Engesser Karl-Heinrich
Published: July 2004

Twenty strains isolated from sewage sludge were found to degrade various ethers, including alkyl ethers, aralkyl ethers, and dibenzyl ether. In
Rhodococcus
strain DEE5151, induction of ether degradation needed substrates exhibiting at least one unsubstituted Cα-methylene moiety as the main structural prerequisite. The cleavage reaction observed with anisole, phenetole, and dibenzyl ether indicates that the initial oxidation occurs at such respective Cα positions. Diethyl ether-induced strain DEE5151 degraded dibenzyl ether via intermediately accumulated benzoic acid. Phenetole seems to be subject also to another ether-cleaving enzyme. Other strains of this group showed different enzymatic activities towards the substrate classes investigated.
Arthrobacter aurescens
TC1 Atrazine Catabolism Genes
trzN
,
atzB
, and
atzC
Are Linked on a 160-Kilobase Region and Are Functional in
Escherichia coli
Authors: Sajjaphan Kannika , Shapir Nir , Wackett Lawrence P. , Palmer Michael , Blackmon Barbara , Tomkins Jeff , Sadowsky Michael J.
Published: July 2004

Arthrobacter aurescens
strain TC1 metabolizes atrazine to cyanuric acid via TrzN, AtzB, and AtzC. The complete sequence of a 160-kb bacterial artificial chromosome clone indicated that
trzN
,
atzB
, and
atzC
are linked on the
A. aurescens
genome. TrzN, AtzB, and AtzC were shown to be functional in
Escherichia coli
. Hybridization studies localized
trzN
,
atzB
, and
atzC
to a 380-kb plasmid in
A. aurescens
strain TC1.
Combining Catalyzed Reporter Deposition-Fluorescence In Situ Hybridization and Microautoradiography To Detect Substrate Utilization by Bacteria and Archaea in the Deep Ocean
Authors: Teira Eva , Reinthaler Thomas , Pernthaler Annelie , Pernthaler Jakob , Herndl Gerhard J.
Published: July 2004

The recently developed CARD-FISH protocol was refined for the detection of marine
Archaea
by replacing the lysozyme permeabilization treatment with proteinase K. This modification resulted in about twofold-higher detection rates for
Archaea
in deep waters. Using this method in combination with microautoradiography, we found that
Archaea
are more abundant than
Bacteria
(42% versus 32% of 4′,6′-diamidino-2-phenylindole counts) in the deep waters of the North Atlantic and that a larger fraction of
Archaea
than of
Bacteria
takes up
l
-aspartic acid (19% versus 10%).
GLOBAL EXISTENCE OF PIECEWISE C1 SOLUTIONS TO THE GENERALIZED RIEMANN PROBLEM
Authors: LI TATSIEN , WANG LIBIN
Published: July 2004

Assuming that each characteristic field is either genuinely nonlinear or linearly degenerate in the sense of Lax, we prove the global existence and uniqueness of piecewise C1 solution containing n small amplitude waves (shocks corresponding to genuinely nonlinear fields and contact discontinuities corresponding to linearly degenerate fields) for the generalized Riemann problem associated with quasilinear hyperbolic systems of conservation laws with small, decaying, piecewise C1 initial data. The solution possesses a global structure similar to that of the similarity solution to the corresponding Riemann problem.
THE WAVE EQUATION ON A THIN DOMAIN: ENERGY DENSITY AND OBSERVABILITY
Authors: FRANCFORT GILLES , GÉRARD PATRICK
Published: July 2004

We compute the limit energy density of solutions of the linear wave equation in a thin three-dimensional domain, if the wavelength of the Cauchy data is bounded from below by the thickness of the domain. As an application, we obtain a geometric criterion for the uniform observability of solutions of a damped wave equation on such a domain.
QUANTUM DOT OPTO-ELECTRONIC DEVICES
Authors: Bhattacharya P. , Ghosh S. , Stiff-Roberts A.D.
Published: July 2004

▪ Abstract  Highly strained semiconductors grow epitaxially on mismatched substrates in the Stranski-Krastanow growth mode, wherein islands are formed after a few monolayers of layer-by-layer growth. Elastic relaxation on the facet edges, renormalization of the surface energy of the facets, and interaction between neighboring islands via the substrate are the driving forces for self-organized growth. The dimensions of the defect-free islands are of the order λB, the de Broglie wavelength, and provide three-dimensional quantum confinement of carriers. Self-organized In(Ga)As/GaAs quantum dots, or quantum boxes, are grown by molecular beam expitaxy (MBE) or metal-organic vapor phase epitaxy (MOVPE) on GaAs, InP, and other substrates and are being incorporated in microelectronic and opto-electronic devices. The use of strain to produce self-organized quantum dots has now become a well-accepted approach and is widely used in III–V semiconductors and other material systems. Much progress has been made in the area of growth, where focus has been on size control, and on optical characterization, where the goal has been the application to lasers and detectors. The unique carrier dynamics in the dots, characterized by femtosecond pump-probe spectroscopy, has led to novel device applications. This article reviews the growth and electronic properties of InGaAs quantum dots and the characteristics of interband and intersublevel lasers and detectors and modulation devices.
BIONANOMECHANICAL SYSTEMS
Authors: Schmidt Jacob J. , Montemagno Carlo D.
Published: July 2004

▪ Abstract  Over the past two decades, advances in biophysical instrumentation have enabled the study of molecular motors at the single molecule level. These studies have inspired the creation of biological/inorganic systems powered by such motors in an attempt to exploit their unique sizes, speeds, functions, and energy utilization capabilities. We give a brief overview of the state-of-the-art of biological and synthetic molecular motors and discuss some initial efforts to exploit their function in engineered structures. We also briefly discuss the construction of devices powered by organized and coordinated arrays of millions of motors in which the growth of cardiac muscle tissue over a microfabricated silicon “skeleton” is directed and controlled.
SYNTHESIS ROUTES FOR LARGE VOLUMES OF NANOPARTICLES
Authors: Masala Ombretta , Seshadri Ram
Published: July 2004

▪ Abstract  This review focuses on the preparation of capped nanoparticles of inorganic materials, classified by composition. The materials described include elemental metals and metalloids (semiconductors), chalcogenide II–VI and IV–VI semiconductors, III–V semiconductors, and oxides (both of simple- and multitransition metal). Although particular emphasis is placed on methods that yield large volumes of nanoparticles, recent novel methods that may not necessarily be scalable are also reviewed. The review makes apparent the richness of chemistry that has become routine to practitioners in the field; diverse inorganic systems with distinct chemistry require distinct methods of preparation.
SELF-ASSEMBLED SEMICONDUCTOR QUANTUM DOTS: Fundamental Physics and Device Applications
Authors: Skolnick M.S. , Mowbray D.J.
Published: July 2004

▪ Abstract  As a result of their fully quantized electronic states and high radiative efficiencies, self-assembled quantum dots have enabled major advances in fundamental physics studies of zero-dimensionality semiconductor systems and in a variety of novel device applications. This article reviews some of the more important recent advances, covering the study and application of both ensembles and single quantum dots. It shows that a comprehensive understanding of the dot electronic structure and dynamical carrier processes is possible and that this knowledge underpins the various device applications.
Recovery of Na-glucose cotransport activity after renal ischemia is impaired in mice lacking vimentin
Authors: Runembert Isabelle , Couette Sylviane , Federici Pierre , Colucci-Guyon Emma , Babinet Charles , Briand Pascale , Friedlander Gérard , Terzi Fabiola
Published: July 2004

Vimentin, an intermediate filament protein mainly expressed in mesenchyma-derived cells, is reexpressed in renal tubular epithelial cells under many pathological conditions, characterized by intense cell proliferation. Whether vimentin reexpression is only a marker of cell dedifferentiation or is instrumental in the maintenance of cell structure and/or function is still unknown. Here, we used vimentin knockout mice ( Vim−/−) and an experimental model of acute renal injury (30-min bilateral renal ischemia) to explore the role of vimentin. Bilateral renal ischemia induced an initial phase of acute tubular necrosis that did not require vimentin and was similar, in terms of morphological and functional changes, in Vim+/+and Vim−/−mice. However, vimentin was essential to favor Na-glucose cotransporter 1 localization to brush-border membranes and to restore Na-glucose cotransport activity in regenerating tubular cells. We show that the effect of vimentin inactivation is specific and results in persistent glucosuria. We propose that vimentin is part of a structural network that favors carrier localization to plasma membranes to restore transport activity in injured kidneys.
Acute regulation of OAT3-mediated estrone sulfate transport in isolated rabbit renal proximal tubules
Authors: Soodvilai S. , Chatsudthipong V. , Evans K. K. , Wright S. H. , Dantzler W. H.
Published: July 2004

We investigated the regulation of organic anion transport driven by the organic anion transporter 3 (OAT3), a multispecific OAT localized at the basolateral membrane of the renal proximal tubule. PMA, a PKC activator, inhibited uptake of estrone sulfate (ES), a prototypic substrate for OAT3, in a dose- and time-dependent manner. This inhibition was reduced by 100 nM bisindoylmaleimide I (BIM), a specific PKC inhibitor. The α1-adrenergic receptor agonist phenylephrine also inhibited ES uptake, and this effect was reduced by BIM. These results suggest that PKC activation downregulates OAT3-mediated organic anion transport. In contrast, epidermal growth factor (EGF) increased ES uptake following activation of MAPK. Exposure to PGE2or dibutyryl (db)-cAMP also enhanced ES uptake. Stimulation produced by PGE2and db-cAMP was prevented by the PKA inhibitor H-89, indicating that this stimulation required PKA activation. In addition, inhibition of cyclooxygenase 1 (COX1) (but not COX2) inhibited ES uptake. Furthermore, the stimulatory effect of EGF was eliminated by inhibition of either COX1 or PKA. These data suggest that EGF stimulates ES uptake by a process in which MAPK activation results in increased PGE2production that, in turn, activates PKA and subsequently stimulates ES uptake. Interestingly, EGF did not induce upregulation immediately following phenylephrine-induced downregulation; and phenylephrine did not induce downregulation immediately after EGF-induced upregulation. These data are the first to show the regulatory response of organic anion transport driven by OAT3 in intact renal proximal tubules.
Analysis and Simulation of Gain Control and Precision in Crayfish Visual Interneurons
Authors: Glantz Raymon M. , Schroeter John P.
Published: July 2004

Impulse trains in sustaining and dimming fibers of crayfish optic lobe (in situ) were elicited with sinusoidal extrinsic current and sine-wave illumination. Extrinsic currents and currents derived from postsynaptic potentials (PSPs) were used to compute the time course of the spike train with an adaptive integrate-and-fire model. The neurons exhibit variations in gain and spike timing precision related to the frequency of stimulation. These phenomena are influenced by spike-frequency adaptation and nonlinearities in the PSP. Dimming fibers exhibit relatively strong spike-frequency adaptation and an associated increase in gain with the frequency of sinusoidal extrinsic current and sine-wave illumination. The dimming fiber IPSP promotes spike train rectification, and rectification contributes to spike timing precision. Sustaining fibers exhibit weaker spike-frequency adaptation and the gain of the current-elicited response is less sensitive to stimulus frequency. The sustaining fiber excitatory PSP, however, exhibits a strong frequency-dependent nonlinearity that influences the frequency response. Spike timing precision is a function of stimulus frequency in all cells and it is enhanced by rectification of the discharge and/or resonance. In rectified responses the jitter in spike times is closely related to the variance in the times the membrane potential reaches spike threshold. These gain and spike timing results are well approximated by the simulated responses. Because the nonlinearity of the sustaining fiber PSP entails a high rate of depolarization, the PSP can increase the precision of spike timing by 10- to 100-fold compared with the response to pure sine-wave stimuli. This enhanced precision has implications for crayfish oculomotor reflexes that are driven by sustaining fibers and highly sensitive to impulse timing during transient excitation.
Comparative Morphology of Rodent Vestibular Periphery. II. Cristae Ampullares
Authors: Desai Sapan S. , Ali Hussain , Lysakowski Anna
Published: July 2004

We made flattened neuroepithelial preparations of horizontal and vertical (anterior and posterior) cristae from mouse, rat, gerbil, guinea pig, chinchilla, and tree squirrel. Calretinin immunohistochemistry was used to label the calyx class of afferents. Because these afferents are restricted to the central zone of the crista, their distribution allowed us to delineate this zone. In addition to calyx afferents, calretinin also labels ∼5% of type I hair cells and 20% of type II hair cells throughout the mouse and rat crista epithelium. Measurements of the dimensions of the cristae and counts of hair cells and calyx afferents were determined on all species. Numbers of calyx afferents, hair cells, area, length, and width of the sensory epithelium increase from mouse to tree squirrel. As in the companion paper, we obtained additional data on vestibular end organ dimensions from the literature to construct a power law function describing the relationship between crista surface area and body weight. The vertical cristae of the mouse, rat, and gerbil have an eminentia cruciatum, a region located transversely along the midpoint of the sensory organ and consisting of nonsensory cells. Apart from this eminentia cruciatum, there are no statistical differences between horizontal and vertical cristae with regard to area, width, length, the number and type of hair cells, and number of calretinin-labeled calyx afferents.
Ulam′s pathological liar game with one half‐lie
Authors: Ellis Robert B. , Yan Catherine H.
Published: July 2004

We introduce a dual game to Ulam′s liar game and consider
the case of one half‐lie. In the original Ulam′s game, Paul
attempts to isolate a distinguished element by disqualifying
all but one of n possibilities with q yes‐no questions, while the responder Carole is allowed to lie a fixed
number k of times. In the dual game, Paul attempts to prevent
disqualification of a distinguished element by “pathological” liar
Carole for as long as possible, given that a possibility associated
with k + 1 lies is disqualified. We consider the half‐lie variant
in which Carole may only lie when the true answer is “no.” We
prove the equivalence of the dual game to the problem of covering
the discrete hypercube with certain asymmetric sets. We define
for the case k = 1 to be the minimum number n such that
Paul can prevent Carole from disqualifying all n elements in q
rounds of questions, and prove that .
Faà di Bruno′s formula and nonhyperbolic fixed points of one‐dimensional maps
Authors: Ponomarenko Vadim
Published: July 2004

Fixed‐point theory of one‐dimensional maps of ℝ
does
not completely address the issue of nonhyperbolic fixed points.
This note generalizes the existing tests to completely classify
all such fixed points. To do this, a family of operators are
exhibited that are analogous to generalizations of the Schwarzian
derivative. In addition, a family of functions f are exhibited
such that the Maclaurin series of f(f(x)) and x are identical.
Old and new generalizations of line graphs
Authors: Bagga Jay
Published: July 2004

Line graphs have been studied for over seventy years. In 1932, H.
Whitney showed that for connected graphs, edge‐isomorphism
implies isomorphism except for K3 and K1,3. The line
graph transformation is one of the most widely studied of all
graph transformations. In its long history, the concept has been
rediscovered several times, with different names such as derived
graph, interchange graph, and edge‐to‐vertex dual. Line graphs
can also be considered as intersection graphs. Several variations
and generalizations of line graphs have been proposed and
studied. These include the concepts of total graphs, path graphs,
and others. In this brief survey we describe these and some more
recent generalizations and extensions including super line graphs
and triangle graphs.
An application of the nonselfadjoint operators theory in the study of stochastic processes
Authors: Abbaoui Lyazid , Debbi Latifa
Published: July 2004

The theory of operator colligations in Hilbert spaces gives rise to certain models for nonselfadjoint operators, called triangular models. These models generalize the spectral decomposition of selfadjoint operators. In this paper, we use the triangular model to obtain the correlation function (CF) of a nonstationary linearly representable stochastic process for which the corresponding operator is simple, dissipative, nonselfadjoint of rank 1, and has real spectrum. As a generalization, we represent the infinitesimal correlation function (ICF) of a nonhomogeneous linearly representable stochastic field in which at least one of the operators has real spectrum.
On a Berry‐Esseen type bound for the maximum likelihood estimator of a parameter for some stochastic partial differential equations
Authors: Mishra M. N. , Rao B. L. S. Prakasa
Published: July 2004

This paper is concerned with the study of the rate of convergence of the distribution of the maximum likelihood estimator of a parameter appearing linearly in the drift coefficients of two types of stochastic partial differential equations (SPDEs).
Long-Term Comparison of the Implantable Cardioverter Defibrillator Versus Amiodarone
Authors: Bokhari Fayez , Newman David , Greene Mary , Korley Victoria , Mangat Iqwal , Dorian Paul
Published: July 2004

Background—

The implantable cardioverter defibrillator (ICD) is superior to amiodarone for secondary prophylaxis of sudden cardiac death. However, the magnitude of this benefit over long-term follow-up is not known. Thus, our objective was to evaluate the long-term consequences of using amiodarone versus an ICD as first-line monotherapy in patients with a prior history of sustained ventricular tachycardia/ventricular fibrillation or cardiac arrest.

Methods and Results—

A total of 120 patients were enrolled at St Michael’s Hospital in the Canadian Implantable Defibrillator Study (CIDS) and were randomly assigned to receive either amiodarone (n=60) or an ICD (n=60). The treatment strategy was not altered after the end of CIDS unless the initial assigned therapy was not effective or was associated with serious side effects. After a mean follow-up of 5.6±2.6 years, there were 28 deaths (47%) in the amiodarone group, compared with 16 deaths (27%) in the ICD group (
P
=0.0213). Total mortality was 5.5% per year in the amiodarone group versus 2.8% per year in the ICD group (hazard ratio of amiodarone: ICD, 2.011; 95% confidence interval, 1.087 to 3.721;
P
=0.0261). In the amiodarone group, 49 patients (82% of all patients) had side effects related to amiodarone, of which 30 patients (50% of all patients) required discontinuation or dose reduction; 19 patients crossed over to ICD because of amiodarone failure (n=7) or side effects (n=12).

Conclusions—

In a subset of CIDS, the benefit of the ICD over amiodarone increases with time; most amiodarone-treated patients eventually develop side effects, have arrhythmia recurrences, or die.
Tissue Plasminogen Activator Antigen and D-Dimer as Markers for Atherothrombotic Risk Among Healthy Postmenopausal Women
Authors: Pradhan Aruna D. , LaCroix Andrea Z. , Langer Robert D. , Trevisan Maurizio , Lewis Cora E. , Hsia Judith A. , Oberman Albert , Kotchen Jane M. , Ridker Paul M
Published: July 2004

Background—

Plasma markers of fibrinolytic function are associated with incident coronary events among several, but not all, prospective epidemiologic investigations of healthy individuals. Few studies have evaluated this relationship in women. In addition, although menopausal hormone therapy (HT) may alter markers of fibrinolytic function, the relevance of this effect for coronary risk assessment has not been studied.

Methods and Results—

In a prospective, nested case-control study among 75 343 postmenopausal women without prior cardiovascular disease or cancer, we evaluated the relationships of elevated tissue plasminogen activator (tPA) antigen and D-dimer with subsequent first coronary heart disease events over a median period of 2.9 years. Baseline levels of both biomarkers were higher among 304 cases compared with 304 controls matched on age, smoking status, ethnicity, and length of follow-up; median values were 9.0 versus 7.4 ng/mL (
P
<0.001) for tPA antigen and 27.6 versus 23.4 ng/mL (
P
=0.001) for D-dimer. In matched-pairs analyses, the odds ratio in the highest versus lowest quartile of tPA antigen was 3.5 (95% CI, 2.1 to 5.8;
P
trend <0.001) and for D-dimer was 2.0 (95% CI, 1.2 to 3.2;
P
trend=0.005). After adjustment for lipid and nonlipid risk factors, including C-reactive protein, tPA antigen remained a significant predictor. Multivariable-adjusted associations for D-dimer, although attenuated, largely remained statistically significant. When stratified by HT, the relationship between tPA antigen and incident coronary heart disease was similar among nonusers, estrogen-only users, and current users of any HT.

Conclusions—

Elevated tPA antigen and, to a lesser extent, D-dimer are independently associated with incident coronary events among postmenopausal women. In analyses stratified by HT, tPA antigen remained a consistent marker of increased coronary risk.
Altered Titin Expression, Myocardial Stiffness, and Left Ventricular Function in Patients With Dilated Cardiomyopathy
Authors: Nagueh Sherif F. , Shah Gopi , Wu Yiming , Torre-Amione Guillermo , King Nicholas M.P. , Lahmers Sunshine , Witt Christian C. , Becker Katy , Labeit Siegfried , Granzier Henk L.
Published: July 2004

Background—

The role of the giant protein titin in patients with heart failure is not well established. We investigated titin expression in patients with end-stage heart failure resulting from nonischemic dilated cardiomyopathy, in particular as it relates to left ventricular (LV) myocardial stiffness and LV function.

Methods and Results—

SDS-agarose gels revealed small N2B (stiff) and large N2BA (compliant) cardiac titin isoforms with a mean N2BA:N2B expression ratio that was significantly (
P
<0.003) increased in 20 heart failure patients versus 6 controls. However, total titin was unchanged. The coexpression ratio was highest in a subsample of patients with an impaired LV relaxation pattern (n=7), intermediate in those with pseudonormal filling (n=6), and lowest in the group with restrictive filling (n=7). Mechanical measurements on LV muscle strips dissected from these hearts (n=8) revealed that passive muscle stiffness was significantly reduced in patients with a high N2BA:N2B expression ratio. Clinical correlations support the relevance of these changes for LV function (assessed by invasive hemodynamics and Doppler echocardiography). A positive correlation between the N2BA:N2B titin isoform ratio and deceleration time of mitral E velocity, A wave transit time, and end diastolic volume/pressure ratio was found. These changes affect exercise tolerance, as indicated by the positive correlation between the N2BA:N2B isoform ratio and peak O
2
consumption (n=10). Upregulated N2BA expression was accompanied by increased expression levels of titin-binding proteins (cardiac ankyrin repeat protein, ankrd2, and diabetes ankyrin repeat protein) that bind to the N2A element of N2BA titin (studied in 13 patients).

Conclusions—

Total titin content was unchanged in end-stage failing hearts and the more compliant N2BA isoform comprised a greater percentage of titin in these hearts. Changes in titin isoform expression in heart failure patients with dilated cardiomyopathy significantly impact diastolic filling by lowering myocardial stiffness. Upregulation of titin-binding proteins indicates that the importance of altered titin expression might extend to cell signaling and regulation of gene expression.
Moderate Daily Intake of Red Wine Inhibits Mural Thrombosis and Monocyte Tissue Factor Expression in an Experimental Porcine Model
Authors: Casani L. , Segales E. , Vilahur G. , de Luna A. Bayes , Badimon L.
Published: July 2004

Background—

Moderate consumption of red wine has been epidemiologically associated with a reduction in cardiovascular disease, but its mechanism of action is not fully understood. The objective was to study whether the protective effects of a daily intake of red wine (Tempranillo, 12.8% alcohol vol/vol) could be related to inhibition of thrombosis in an experimental model of diet-induced hyperlipemia.

Methods and Results—

For 100 days, animals were fed a western-type proatherogenic diet containing 2% cholesterol and 20% saturated fat. Three doses of red wine were studied (20, 30, and 40 g wine-ethanol/d) and compared with placebo-control animals not taking any wine. Thrombosis under flow conditions was evaluated by radioisotopic quantification of deposited platelets on damaged arteries. Changes in RhoA translocation in platelets and monocyte tissue factor expression were also analyzed. Mural platelet deposition was significantly reduced in animals ingesting red wine with their food. Expression of RhoA in the platelet cytoplasm (inactive form) was increased in wine-fed animals. Tissue factor mRNA expression in lipopolysaccharide-stimulated monocytes was reduced in wine-fed animals. Total cholesterol levels were not significantly different among groups.

Conclusions—

Moderate red wine intake significantly reduces platelet deposition triggered by damaged vessel wall, partially explained by inhibition of RhoA translocation to the platelet membrane. Hence, a daily moderate intake of wine seems to inhibit different pathways that converge in a reduced thrombotic risk on vessel wall injury.
Atorvastatin Prevents End-Organ Injury in Salt-Sensitive Hypertension
Authors: Zhou Ming-Sheng , Jaimes Edgar A. , Raij Leopoldo
Published: July 2004

Statins, inhibitors of cholesterol biosynthesis, are endowed with pleiotropic effects that may contribute to their favorable clinical results. Hypertensive Dahl salt-sensitive (DS) rats have endothelial dysfunction and cardiorenal injury associated with decreased NO bioavailability and increased superoxide (O
2
−
) production linked to a functional upregulation of angiotensin II. We investigated whether atorvastatin (30 mg/kg per day; by gavage) would prevent endothelial nitric oxide (eNOS) downregulation and the increase in O
2
−
in DS rats, thereby reducing end-organ injury. DS rats given a high-salt diet (4% NaCl) for 10 weeks developed hypertension (systolic blood pressure [SBP] 200±8 versus 150±2 mm Hg in DS rats fed 0.5% NaCl diet [NS];
P
<0.05), impaired endothelium-dependent relaxation, functional upregulation of endothelin-1, left ventricular hypertrophy (LVH; 30%), and proteinuria (167%), accompanied by downregulation of aortic eNOS activity (0.7±0.2 versus 1.8±0.3 nmol/min per gram protein in NS;
P
<0.05) and increased aortic O
2
−
(2632±316 versus 1176±112 counts/min per milligram in NS;
P
<0.05) and plasma 8-F
2
α isoprostanes. Atorvastatin prevented the decrease in eNOS activity (1.5±0.3 nmol/min per gram protein) as well as the increase in O
2
−
(1192±243 counts/min per milligram) and plasma 8-F
2
α isoprostanes, reduced LVH and proteinuria, and normalized endothelial function and vascular response to endothelin-1, although reduction in SBP was modest (174±8 mm Hg). Atorvastatin combined with removal of high salt normalized aortic eNOS activity, SBP, LVH, and proteinuria. These findings strongly suggest that concomitant prevention of vascular eNOS downregulation and inhibition of oxidative stress may contribute to the protection against end-organ injury afforded by this statin in salt-sensitive hypertension.
GPI-anchor deficiency in myeloid cells causes impaired FcγR effector functions
Authors: Hazenbos Wouter L. W. , Clausen Björn E. , Takeda Junji , Kinoshita Taroh
Published: July 2004

Signaling by transmembrane immunoglobulin G (IgG)-Fc receptors (FcγRs) in response to ligand involves association with membrane microdomains that contain glycosyl phosphatidylinositol (GPI)-anchored proteins. Recent in vitro studies showed enhancement of FcγR signaling by forced monoclonal antibody-mediated cocrosslinking with various GPI-anchored proteins. Here, the possibility that GPI-anchored proteins are involved in normal physiologic FcγR effector functions in response to a model ligand was studied using myeloid-specific GPI-anchor-deficient mice, generated by Cre-loxP conditional targeting. GPI-anchor-deficient primary myeloid cells exhibited normal FcγR expression and binding or endocytosis of IgG-immune complexes (IgG-ICs). Strikingly, after stimulation with IgG-ICs, tumor necrosis factor-α release, dendritic cell maturation, and antigen presentation were strongly reduced by GPI-anchor deficiency. Tyrosine phosphorylation of the FcR γ-chain in response to IgG-IC was impaired in GPI-anchor-deficient cells. Myeloid GPI-anchor deficiency resulted in attenuated in vivo inflammatory processes during IgG-IC-mediated alveolitis. This study provides the first genetic evidence for an essential role of GPI-anchored proteins in physiologic FcγR effector functions in vitro and in vivo. (Blood. 2004;104:2825-2831)