bluuebunny/crossref_metadata_2025 huggingface dataset:
Proteomic and microscopic analysis of biofilms formed byListeria monocytogenes568
Authors: Hefford M A , D'Aoust S , Cyr T D , Austin J W , Sanders G , Kheradpir E , Kalmokoff M L
Published: May 2005

Biofilm formation may be important in the colonization of the food-processing environment by the food-borne pathogen Listeria monocytogenes. Listeria monocytogenes 568 formed adherent multicellular layers on a variety of test surfaces following growth at 37 °C with multiple transfers of the test surface into fresh medium. Microscopic examination of these adherent layers suggest that the cells were surrounded by extracellular material. The presence of a carbohydrate containing extracellular polymeric matrix was confirmed by labelling hydrated adherent layers with fluorescein-conjugated concanavalin A, indicating that these adherent layers are biofilms. To gain insight into the physiological state of cells in these biofilms, the proteomes from biofilm- and planktonic-grown cells from the same cultures were compared using 2-dimensional polyacrylamide gel electrophoresis. Nineteen proteins, which exhibited higher levels of expression in biofilm-grown cells, were successfully identified from the 2-D gels using a combination of MALDI-TOF and MS/MS. Proteins that were found to be more highly expressed in biofilm-grown cells were involved in stress response, envelope and protein synthesis, biosynthesis, energy generation, and regulatory functions. In biofilm-grown cells, many proteins in the pH range 4–6 ran as multiple spots arranged horizontally across the 2-D gels.Key words: Listeria monocytogenes, biofilms, proteomics, stress response.
Hydrocarbon biodegradation in oxygen-limited sequential batch reactors by consortium from weathered, oil-contaminated soil
Authors: Medina-Moreno S A , Huerta-Ochoa S , Gutiérrez-Rojas M
Published: May 2005

We studied the use of sequential batch reactors under oxygen limitation to improve and maintain consortium ability to biodegrade hydrocarbons. Air-agitated tubular reactors (2.5 L) were operated for 20 sequential 21-day cycles. Maya crude oil – paraffin mixture (13 000 mg/L) was used as the sole carbon source. The reactors were inoculated with a consortium from the rhizosphere of Cyperus laxus, a native plant that grows naturally in weathered, contaminated soil. Oxygen limitation was induced in the tubular reactor by maintaining low oxygen transfer coefficients (kLa < 20.6 h–1). The extent and biodegradation rates increased significantly up to the fourth cycle, maintaining values of about 66.33% and 460 mg·L–1·d–1, respectively. Thereafter, sequential batch reactor operation exhibited a pattern with a constant general trend of biodegradation. The effect of oxygen limitation on consortium activity led to a low biomass yield and non-soluble metabolite (0.45 g SS/g hydrocarbons consumed). The average number of hydrocarbon-degrading microorganisms increased from 6.5 × 107 (cycles 1–3) to 2.2 × 108 (cycles 4–20). Five bacterial strains were identified: Achromobacter (Alcaligenes) xylosoxidans, Bacillus cereus, Bacillus subtilis, Brevibacterium luteum, and Pseudomonas pseudoalcaligenes. Asphaltene-free total petroleum hydrocarbons, extracted from a weathered, contaminated soil, were also biodegraded (97.1 mg·L–1·d–1) and mineralized (210.48 mg CO2·L–1·d–1) by the enriched consortium without inhibition. Our results indicate that sequential batch reactors under oxygen limitation can be used to produce consortia with high and constant biodegradation ability for industrial applications of bioremediation.Key words: sequential batch reactors, oxygen limitation, consortium, hydrocarbon biodegradation.
Stress-survival responses of a carbon-starvedp-nitrophenol-mineralizingMoraxellastrain in river water
Authors: Moore Michael , Trevors Jack , Lee Hung , Leung Kam Tin
Published: May 2005

The effect of carbon starvation on the stress-resistant responses of a p-nitrophenol-mineralizing Moraxella strain was examined in both buffer and river water samples. The Moraxella strain showed optimal stress-resistant responses in a minimal salt buffer when carbon-starved for 1–2 d. In the buffer system, the 1- and 2-day carbon-starved Moraxella cultures survived about 150-, 200-, and 100-fold better than the non-starved cultures when exposed to 43.5 °C, 2.7 mol/L NaCl, and 500 µmol/L H2O2for 4 h, respectively. A green fluorescent protein gene- (gfp) labelled derivative of the Moraxella strain was used to examine the stress-resistant responses of the bacterium in natural river water microcosms. The carbon-starved gfp-labelled Moraxella strain also showed stress-resistant responses against heat, osmotic, and oxidative stresses in the river water samples. Despite the stress-tolerant capability of the carbon-starved gfp-labelled Moraxella cells, they did not exhibit any survival advantage over their non-starved counterparts when inoculated into river water microcosms and incubated at 10 and 22 °C for 14 d.Key words: carbon starvation, stress-survival responses, Moraxella, p-nitrophenol, green fluorescent protein gene.
Characterization ofcopABCDoperon from a copper-sensitivePseudomonasputidastrain
Authors: Adaikkalam Vellaichamy , Swarup Sanjay
Published: May 2005

We describe an operon, copABCD, that encodes copper-binding and sequestering proteins for copper homeostasis in the copper-sensitive strain Pseudomonas putida PNL-MK25. This is the second operon characterized as being involved in copper homeostasis, in addition to a P1-type ATPase encoded by cueAR, which was previously shown to be active in the same strain. In this study, 3 copper-responsive mutants were obtained through mini-Tn5::gfp mutagenesis and were found to exhibit reduced tolerance to copper. Sequencing analysis of the transposon-tagged region in the 3 mutants revealed insertions in 2 genes of an operon homologous to the copABCD of P. syringae and pcoABCD of Escherichia coli. Gene expression studies demonstrated that the P. putida copABCD is inducible starting from 3 µmol/L copper levels. Copper-sensitivity studies revealed that the tolerance of the mutant strains was reduced only marginally (only 0.16-fold) in comparison to a 6-fold reduced tolerance of the cueAR mutant. Thus, the cop operon in this strain has a minimal role when compared with its role both in other copper-resistant strains, such as P. syringae pv. syringae, and in the cueAR operon of the same strain. We propose that the reduced function of the copABCD operon is likely to be due to the presence of fewer metal-binding domains in the encoded proteins.Key words: cop operon, copper-binding proteins, mini-Tn5::gfp mutagenesis, transition metal.
Scanning electron microscopy analysis of agedMycobacterium tuberculosiscells
Authors: Dahl John L
Published: May 2005

Most electron microscopy studies of Mycobacterium tuberculosis ultrastructure were performed in the 1950s and 1960s and lack high resolution by modern standards. This study was performed to re-evaluate the fine structure of M. tuberculosis using modern scanning electron microscopy. Bacteria were grown in rich medium with a constant supply of oxygen for several weeks. Results show that surface bleb-like structures accumulate as cultures age. The most unusual feature of aging M. tuberculosis cultures is that they develop extracellular fibrils, which could play roles of adhering cells to surfaces and to one another.Key words: Mycobacterium tuberculosis, SEM, stationary phase, surface blebs, extracellular fibrils.
KDK BASED DOUBLE-BASIS FUSION MECHANISM AND ITS PROCESS MODEL
Authors: YANG BINGRU , SHEN JIANGTAO , SONG WEI
Published: June 2005

Knowledge Discovery in Knowledge Base (KDK) opens new horizons for research. KDK and KDD (Knowledge Discovery in Database) are the different cognitive field and discovery process. In most people's view, they are independent each other. In this paper we can summarize the following tasks: Firstly, we discussed that two kinds of the process model and mining algorithm of KDK based on facts and rules in knowledge base. Secondly, we proves that the inherent relation between KDD and KDK (i.e. double-basis fusion mechanism). Thirdly, we gained the new process model and implementation technology of KDK*. Finally, the imitation experimentation proved that the validity of above mechanism and process model.
A COMMON CHARACTERISTIC KNOWLEDGE DISCOVERY SYSTEM IN DISTRIBUTED COMPUTING ENVIRONMENT
Authors: RYU TAE W.
Published: June 2005

This paper describes an automated query discovery system for retrieving common characteristic knowledge from a database in a distributed computing environment. The paper particularly centers on the problem of discovering the common characteristics that are shared by a set of objects in a database. This type of commonalities can be useful in finding a typical profile for the given object set or outstanding features for a group of objects in a database. In our approach, commonalities within a set of objects are described by database queries that compute the given set of objects. We use the genetic programming as a major search engine to discover such queries. The paper discusses the architecture and the techniques used in our system, and presents some experimental results to evaluate the system. In addition, for the performance improvement, we built a distributed computing environment for our system with clustered computers using the Common Object Request Broker Architecture (CORBA). The paper briefly discusses our clustered computer architecture, the implementation of distributed computing environment, and shows the overall performance improvement.
REAL TIME INFERENCE IN BAYESIAN NETWORKS: AN ANYTIME APPROACH
Authors: KHREISAT LAILA
Published: June 2005

One of the major challenges facing real time world applications that employ Bayesian networks, is the design and development of efficient inference algorithms. In this paper we present an approximate real time inference algorithm for Bayesian Networks. The algorithm is an anytime reasoning method based on probabilistic inequalities, capable of handling fully and partially quantified Bayesian networks. In our method the accuracy of the results improve gradually as computation time increases, providing a trade-off between resource consumption and output quality. The method is tractable in providing the initial answers, as well as complete in the limiting case.
REDUCING THE TIME COMPLEXITY OF THE N-QUEENS PROBLEM
Authors: EL-QAWASMEH EYAS , AL-NOUBANI KHADER
Published: June 2005

This paper presents a fast algorithm for solving the n-queens problem. The basic idea of this algorithm is to use pre-computed solutions in 75% of the cases, while the remaining cases are solved by calling the Sosic's algorithm. The novelty of this algorithm is in the observation that these pre-computable cases exhibit a modular nature. In addition, the pre-computed solutions run 100 times faster than Sosic's algorithm in most cases.
TESTS OF THE DYNAMICS OF DEEP INELASTIC COLLISIONS
Authors: SHVEDOV L. , BŁOCKI J. , WILCZYŃSKI J.
Published: June 2005

A macroscopic dynamical model of deep-inelastic nucleus-nucleus collisions is presented. We solve Rayleigh-Lagrange equations of motion assuming the mechanism of one-body dissipation. Sensitivity of the model to the assumed strength of the dissipative Rayleigh force (relative to the one-body dissipation) is discussed.
INFLUENCE OF THE ENTRANCE CHANNEL EFFECTS ON THE FORMATION PROCESS OF SUPERHEAVY ELEMENTS
Authors: KOWAL M. , ŁOJEWSKI Z.
Published: June 2005

For the description of heavy-ions collisions the importance of multipole deformations of the reaction partners beyond the quadrupole deformation is investigated in particular on fusion cross sections, barrier and spin distributions. The role of fragment orientation in a collision is studied. We have applied our method to Ca – induced reactions leading to superheavy nuclei recently discovered at the Flerov Laboratory of Nuclear Reactions in Dubna. We will show that our predictions are very well confirmed by the recent experiments.
SHELL CORRECTION ENERGIES IN CALCULATIONS OF THE SURVIVAL PROBABILITY
Authors: SIWEK-WILCZYŃSKA K. , SKWIRA I. , WILCZYŃSKI J.
Published: June 2005

Analysis of existing data on experimental fission barriers for about 90 nuclei shows that the shell correction energy practically vanishes at the barrier configuration. Statistical model calculations, with shell effects accounted for by the Ignatyuk formula, were carried out for the decay of the 248 Cf compound nucleus assuming the ground state shell corrections of Möller et al., and the vanishing shell correction energy at the barrier. The results are consistent with existing experimental data on fusion- and xn evaporation-residue cross sections in the 12 C +236 U reaction.
FUSION BARRIER DISTRIBUTIONS IN 20,22Ne+natNi
Authors: ŚWIDERSKI Ł. , PIASECKI E. , CZOSNYKA P. , KROGULSKI T. , ROWLEY N.
Published: June 2005

Barriers height distributions for 20,22 Ne on nat Ni have been measured using quasi-elastic scattering at backward angles. The results have been compared to coupled-channels calculations performed with the CCQUEL code. A fair agreement with data has been obtained if the values of a hexadecapole deformation parameters of 20 Ne and 22 Ne are reduced by a factor of 2 with respect to their previously quoted values.
HOW TO CALIBRATE THE TIME SCALE OF EMISSION OF INTERMEDIATE MASS FRAGMENTS
Authors: WILCZYŃSKI J. , DE FILIPPO E. , PAGANO A. , AMORINI F. , ANZALONE A. , AUDITORE L. , BARAN V. , BERCEANU I. , BLICHARSKA J. , BRZYCHCZYK J. , BONASERA A. , BORDERIE B. , BOGAULT R. , BRUNO M. , CARDELLA G. , CAVALLARO S. , CHATTERJEE M. B. , CHBIHI A. , CIBOR J. , COLONNA M. , D'AGOSTINO M. , DAYRAS R. , DI TORO M. , FRANKLAND J. , GALICHET E. , GAWLIKOWICZ W. , GERACI E. , GIUSTOLISI F. , GRZESZCZUK A. , GUAZZONI P. , GUINET D. , IACONO-MANNO M. , KOWALSKI S. , LA GUIDARA E. , LANZANO G. , LANZALONE G. , LE NEINDRE N. , LI S. , MAIOLINO C. , MAJKA Z. , PAPA M. , PETROVICI M. , PIASECKI E. , PIRRONE S. , PŁANETA R. , POLITI G. , POP A. , PORTO F. , RIVET M. F. , ROSATO E. , RIZZO F. , RUSSO S. , RUSSOTTO P. , SASSI M. , SCHMIDT K. , SIWEK-WILCZYŃSKA K. , SKWIRA I. , SPERDUTO M. L. , ŚWIDERSKI Ł. , TRIFIRÒ A. , TRIMARCHI M. , VANNINI G. , VIGILANTE M. , WIELECZKO J. P. , WU H. , XIAO Z. , ZETTA L. , ZIPPER W.
Published: June 2005

In order to obtain information on the time sequence and time scale of the production of intermediate mass fragments (IMF) in nucleus-nucleus collisions at intermediate energies it is proposed to analyze correlations between relative velocities of IMF's with respect to projectile-like fragments (PLF) and target-like fragments (TLF). Experimental data on the production of IMF's in the 124 Sn +64 Ni reaction, taken with the CHIMERA multidetector array at 35 MeV/nucleon, have been analyzed with the proposed method.
FISSION BARRIERS IN THE HEAVIEST NUCLEI USING THE GREEN'S FUNCTION OSCILLATOR EXPANSION METHOD
Authors: DUDEK W. , ĆWIOK S. , KASZYŃSKI P.
Published: June 2005

A macroscopic-microscopic method with the finite deformed Woods-Saxon potential is used to calculate shell corrections in superheavy nuclei. The Green's function oscillator expansion method and the generalized Strutinsky smoothing procedure are applied. It is shown that the spurious contribution to the deformation energy along the fission path due to the unphysical particle gas appearing in the standard method can be as large as 1 MeV, being almost independent of deformation. So, its effect on fission barrier heights is small.
SKYRME–HARTREE–FOCK CALCULATIONS OF FISSION BARRIERS OF THE HEAVIEST AND SUPERHEAVY NUCLEI
Authors: STASZCZAK ANDRZEJ , DOBACZEWSKI JACEK , NAZAREWICZ WITOLD
Published: June 2005

Self-consistent Skyrme–Hartree–Fock (SHF) calculations of static fission barriers are presented for even-even Fermium isotopes as well as for superheavy even-even N=184 isotones. In the particle-hole channel, we use the SLy4 Skyrme parametrization, while in the particle-particle channel we take a T=1 seniority pairing force treated in the BCS approximation. The influence of reflection-asymmetric and triaxial degrees of freedom on the static fission paths are investigated.
ROLE OF HIGHER MULTIPOLARITY DEFORMATIONS IN THE HEIGHT OF FISSION BARRIER OF A DEFORMED HEAVY NUCLEUS
Authors: SOBICZEWSKI A. , MUNTIAN I.
Published: June 2005

Role of higher-multipolarity deformations of a nucleus in its (static) fission-barrier height [Formula: see text] is studied. The study is done within a macroscopic-microscopic approach. A heavy deformed nucleus 250 Cf is taken for the analysis. It is found that, in the case of axially symmetric shapes, the inclusion of higher-multipolarity deformations increases [Formula: see text].
ROLE OF HIGHER MULTIPOLARITY DEFORMATIONS IN THE FISSION-BARRIER HEIGHT OF A SPHERICAL SUPERHEAVY NUCLEUS
Authors: MUNTIAN I. , SOBICZEWSKI A.
Published: June 2005

Role of the dimension of deformation space used in calculations of the (static) fission-barrier height [Formula: see text] is analyzed for a spherical nucleus. The superheavy nucleus 294116 is taken for the analysis. The study is done within a macroscopic-microscopic approach. It is found that the barrier height [Formula: see text] importantly decreases with increasing dimension of the space.
NEUTRON–PROTON PAIRING IN 64Ge
Authors: BARAN ANDRZEJ , SIEJA KAMILA
Published: June 2005

Isotopes of germanium are studied in the framework of the relativistic mean-field theory with a δ-pairing type residual interaction. Both pairing channels T=1 and T=0 are included. The T=0 channel does not contribute to the pairing energy even with a large coupling strength of the δ force. It is shown that the Wigner-like term (congruence energy) may be partly reproduced by T=1, Tz=0 neutron-proton pairing which is remarkably strong in the case of Z=N nuclei.
PROBING SPIN FIELDS AND SPIN-ORBIT TERM OF THE LOCAL NUCLEAR ENERGY FUNCTIONAL AT BAND TERMINATION
Authors: ZDUŃCZUK H. , SATUŁA W. , WYSS R. A.
Published: June 2005

A systematic study of the terminating states in A~50 mass region using the self-consistent Skyrme-Hartree-Fock model is presented. The objective is to use the intrinsic simplicity of the terminating states to constrain certain parameters of the local nuclear energy functional. In particular, the work focuses on the spin fields and the spin-orbit term and constrain the appropriate Landau parameters and the strength of the spin-orbit potential.
INFLUENCE OF DIFFERENT PROTON AND NEUTRON DEFORMATIONS ON NUCLEAR ENERGIES
Authors: DOBROWOLSKI ARTUR , BARTEL JOHANN , POMORSKI KRZYSZTOF
Published: June 2005

The response of nuclear energy with respect the change of proton and neutron distributions is investigated. Contrary to most macroscopic-microscopic approaches, different radii and multipole deformations of both distributions are admitted here. The average part of the total energy is evaluated using the Yukawa-folded model, while the microscopic energy corrections are obtained within the Strutinsky and BCS methods.
LOCALIZATION ON FAT BRANES AS THE SOURCE OF NEUTRINO MIXING
Authors: GÓŹDŹ MAREK , KAMIŃSKI WIESŁAW A.
Published: June 2005

The localization of fermions in extra dimensions, proposed by Arkani-Hamed and Schmaltz, is discussed as the source of the phenomenon of particle mixing. We work out the example of neutrinos in detail.
PROJECTION EVOLUTION AND DECAY OF A SYSTEM
Authors: GÓŹDŹ A. , DȨBICKI M. , PIETROW M.
Published: June 2005

We show that the projection evolution approach can reproduce the exponential decay law. The method can be potentially used to calculate the lifetimes of decaying nuclei.
THE PROBLEM OF UNIVERSALITY OF NUCLEAR MEAN-FIELD PARAMETRIZATIONS
Authors: DUBRAY NOËL , DUDEK JERZY , SCHUNCK NICOLAS
Published: June 2005

Most of the microscopic self-consistent approaches such as Hartree-Fock and/or Relativistic Mean Field theories use ensembles of a few adjustable parameters that are independent of the proton and neutron numbers and fixed once for all. This feature is referred to as the universality of the parametrization. It is further developed for the case of the phenomenological description of the nuclear deformed mean-field e.g. in the Woods-Saxon form and discussed in view of obtaining the parametrizations that are most stable with respect to extrapolations for the unknown nuclear ranges as e.g. in the case of various groups exotic nuclei. A new universal parametrization is obtained and an illustration presented.
TEMPERATURE DEPENDENCE OF THE NUCLEAR ENERGY IN RELATIVISTIC MEAN-FIELD THEORY
Authors: NERLO-POMORSKA B. , POMORSKI K. , SYKUT J. , BARTEL J.
Published: June 2005

Self-consistent relativistic mean-field (RMF) calculations with the NL3 parameter set were performed for 171 spherical even-even nuclei with 16≤A≤224 at temperatures in the range 0≤T≤4 MeV . For this sample of nuclei single-particle level densities are determined by analyzing the data obtained for various temperatures. A new shell-correction method is used to evaluate shell effects at all temperatures. The single-particle level density is expressed as function of mass number A and relative isospin I and compared with previous estimates.
A PROBABILISTIC GENERALIZATION OF SUBNORMALITY
Authors: DAMIAN ERIKA , LUCCHINI ANDREA
Published: May 2005

A subnormal subgroup X of G has the following property: there exists a Dirichlet polynomial Q(s) with integer coefficients such that, for each t ∈ ℕ, Q(t) is the conditional probability that t random elements generate G given that they generate G together with the elements of X In this paper we analyze how far can a subgroup X be with this property from being a subnormal subgroup.
ANDERSÉN–LEMPERT-THEORY WITH PARAMETERS: A REPRESENTATION THEORETIC POINT OF VIEW
Authors: KUTZSCHEBAUCH FRANK
Published: May 2005

We calculate the invariant subspaces in the linear representation of the group of algebraic automorphisms of ℂnon the vector space of algebraic vector fields on ℂnand more generally we do this in a setting with parameter. As an application to the field of Several Complex Variables we get a new proof of the Andersén–Lempert observation and a parametric version of the Andersén–Lempert theorem. Further applications to the question of embeddings of ℂkinto ℂnare announced.
MODELING A THERMAL IMAGING PROCESS IN AN IMPACT DAMAGED COMPOSITE STRUCTURE
Authors: ISKANDARANI M. Z. , SHILBAYEH N. F.
Published: May 2005

An innovative NDT (non-destructive testing) technique for interrogating materials for their defects has been developed successfully. The technique has a novel approach to data analysis by employing intensity, RGB signal re-mix and wavelength variation of a thermally generated IR-beam onto the specimen under test which can be sensed and displayed on a computer screen as an image. Specimen inspection and data analysis are carried out through pixel level re-ordering and shelving techniques within a transformed image file using a sequence grouping and regrouping software system, which is specifically developed for this work. The interaction between an impact damaged RIM composite structure and thermal energy is recorded, analyzed, and modeled using an equivalent Electronic circuit. Effect of impact damage on the integrity of the composite structure is also discussed.
ADAPTIVE LEAST SQUARES ACQUISITION OF HIGH RESOLUTION IMAGES
Authors: EL-KHAMY S. E. , HADHOUD M. M. , DESSOUKY M. I. , SALAM B. M. , EL-SAMIE F. E. ABD
Published: May 2005

This paper presents a least squares block by block adaptive approach for the acquisition of high resolution (HR) images from available (LR) images. The suggested algorithm is based on the segmentation of the image to overlapping blocks and the interpolation of each block separately. The purpose of the overlapping of blocks is to avoid edge effects. An adaptive 2D least squares approach, which considers the image acquisition model, is used in the minimization of the estimation error of each block. In this suggested algorithm, a weight matrix of moderate dimensions is estimated in a small number of iterations to interpolate each block. This algorithm avoids the large computational complexity due to the matrices of large dimensions required to interpolate the image as a whole. The performance of the proposed algorithm is studied for different LR images with different SNRs. The performance of the proposed algorithm is also compared to the standard as well as the warped distance cubic O-MOMS image interpolation algorithms from the PSNR point of view.
IL-6 activates serum and glucocorticoid kinase via p38α mitogen-activated protein kinase pathway
Authors: Meng Fanyin , Yamagiwa Yoko , Taffetani Silvia , Han Jiahuai , Patel Tushar
Published: May 2005

Interleukin-6 (IL-6) has been implicated as an autocrine factor involved in growth of several human cancers, such as tumors arising from the biliary tract or cholangiocarcinoma. In malignant biliary tract epithelia, IL-6 activates the p38 MAPK pathway, which mediates a dominant survival signaling pathway. Serum and glucocorticoid-stimulated kinase (SGK) has been implicated as a survival kinase, but its role in survival signaling by IL-6 is unknown. After IL-6 stimulation, p38 MAPK activation preceded phosphorylation of SGK at Ser78. Pretreatment with the pharmacological inhibitors of p38 MAPK SB-203580 or SB-202190 blocked IL-6-induced SGK phosphorylation at Ser78 and SGK activation. Overexpression of p38α increased constitutive SGK phosphorylation at Ser78, whereas dominant negative p38α MAPK blocked IL-6-induced SGK phosphorylation and nuclear translocation. Interestingly, in addition to stimulating SGK phosphorylation, both IL-6 stimulation and p38α MAPK overexpression increased SGK mRNA and protein expression. An increase in p38 MAPK and SGK occurred following enforced expression of IL-6 in vivo. Furthermore, inhibition of SGK expression by siRNA increased toxicity due to chemotherapeutic drugs. Taken together, these data identify SGK as both a downstream kinase substrate as well as a transcriptionally regulated gene target of p38 MAPK in response to IL-6 and support a role of SGK during survival signaling by IL-6 in human cancers, such as cholangiocarcinoma.
Intracellular location regulates calcium-calmodulin-dependent activation of organelle-restricted eNOS
Authors: Jagnandan Davin , Sessa William C. , Fulton David
Published: May 2005

Mislocalization of endothelial nitric oxide (NO) synthase (eNOS) in response to oxidized low-density lipoprotein, cholesterol depletion, elevated blood pressure, and bound eNOS interacting protein/NOS traffic inducer is associated with reduced NO release via unknown mechanisms. The proper targeting of eNOS to the plasma membrane or intracellular organelles is an important regulatory step controlling enzyme activity. Previous studies have shown that plasma membrane eNOS is constitutively phosphorylated on serine 1179 and highly active. In contrast, the activity of eNOS targeted to intracellular organelles is more complex. The cis-Golgi eNOS is fully activated by Akt-dependent phosphorylation. However, eNOS targeted to the trans-Golgi is decidedly less active in response to all modes of activation, including mutation to the phosphomimetic aspartic acid. In this study, we establish that when expressed within other intracellular organelles, such as the mitochondria and nucleus, the activity of eNOS is also greatly reduced. To address the mechanisms underlying the impaired catalytic activity of eNOS within these locations, we generated subcellular-targeted constructs that express a calcium-independent NOS isoform, iNOS. With the use of organelle specific (plasma membrane, cis- vs. trans-Golgi, plasma membrane, and Golgi, nucleus, and mitochondria) targeting motifs fused to the wild-type iNOS, we measured NO release from intact cells. With the exception of the Golgi lumen, our results showed no impairment in the ability of targeted iNOS to synthesize NO. Confirmation of correct targeting was obtained through confocal microscopy using identical constructs fused to the green fluorescent protein. We conclude that the reduced activation of eNOS within discrete cytoplasmic regions of the Golgi, the mitochondria and the nucleus is primarily due to insufficient access to calcium-calmodulin.
Hepatic glucose regulation and metabolism in adult sheep: effects of prenatal betamethasone
Authors: Sloboda Deborah M. , Moss Timothy J. M. , Li Shaofu , Doherty Dorota A. , Nitsos Ilias , Challis John R. G. , Newnham John P.
Published: June 2005

Fetal exposure to synthetic glucocorticoids in sheep results in increased fetal hepatic 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and corticosteroid-binding globulin (CBG) protein levels and insulin resistance in postnatal life. The aim was to determine whether these changes persisted to adulthood and whether alterations in mediators of hepatic glucocorticoid and glucose regulation contributed to changes in metabolism. Pregnant ewes or their fetuses received either repeated intramuscular saline (MS, FS) or betamethasone injections (0.5 mg/kg; M4, F4) at 104, 111, 118, and 124 days of gestation (dG), or a single betamethasone injection at 104 dG followed by saline at 111, 118, and 124 dG (M1, F1). Offspring were catheterized at 2 and 3 yr of age and given an intravenous glucose challenge (0.5 mg/kg). Hepatic tissue was collected at 3.5 yr. At 2 yr of age, basal plasma insulin was elevated in M4 offspring and at 3 yr of age was elevated in F4 offspring. Basal insulin-to-glucose ratio was significantly elevated in M4 offspring at 2 yr of age and elevated in M1, M4, and F4 offspring at 3 yr of age. All betamethasone treatments resulted in significant increases in hepatic glucose-6-phosphatase (G-6-Pase) activity. Hepatic glucocorticoid receptor protein levels were not altered in M1 and M4 offspring but were increased in F1 and F4 offspring. Hepatic CBG protein levels were lower in F4 but not F1 offspring and were unchanged from control in M1 and M4 offspring. Prenatal betamethasone exposure results in elevated hepatic G-6-Pase activity in adulthood and may contribute to long-term changes in metabolism.
Effects of overexpression of pancreatic derived factor (FAM3B) in isolated mouse islets and insulin-secreting βTC3 cells
Authors: Cao Xiaopei , Yang Jichun , Burkhardt Brant R. , Gao Zhiyong , Wong Ryan K. , Greene Scott R. , Wu Jianmei , Wolf Bryan A.
Published: June 2005

PANcreatic DERived factor (PANDER, FAM3B) is a recently discovered islet-specific cytokine. We have previously shown that, in vitro, truncated recombinant PANDER isoforms (20 and 21 kDa) are cytotoxic to β-cell lines but the effects of full-length PANDER on islet biology remain unclear. In this study, we used adenovirus (Ad-PANDER) to overexpress full-length cDNA of PANDER in islets and βTC3 cells. βTC3 cells were infected with Ad-PANDER or control vector. After 48 h, cell viability was significantly decreased as evaluated by MTT assay. The number of dead cells was significantly increased as indicated by the fluorescent intensity of the propidium iodide-stained cells (160 ± 13 vs. control 100 ± 7%, P = 0.001). Flow cytometric Tunel assay showed that overexpressing PANDER induced a significant fourfold increase in β-cell apoptosis (19.4 ± 6.3 vs. control 4.1 ± 0.8%, P < 0.05). There was a significant increase in the number of annexin V-positive (apoptotic) cells and propidium iodide-positive (dead) cells in mouse islets infected with Ad-PANDER compared with control cells infected with Ad-LacZ. Addition of 4 nM recombinant PANDER protein to βTC3 cells or infection of Ad-PANDER did not affect Akt and STAT1 phosphorylation, Bcl-2, Fas, and NF-κB protein levels. However, activation of caspase-3 was observed in βTC3 and islets infected with Ad-PANDER. Overexpression of PANDER in mouse islets or addition of recombinant PANDER decreased insulin secretion induced by carbachol plus glucose or high potassium but not that by glucose alone. Culture with recombinant PANDER did not affect glucose-induced NAD(P)H elevation in mouse islets. In conclusion, Ad-PANDER infection is as effective as truncated recombinant PANDER to induce βTC3 cell and mouse islet apoptosis.
Hypoxic stress in diabetic pregnancy contributes to impaired embryo gene expression and defective development by inducing oxidative stress
Authors: Li Rulin , Chase Martha , Jung Sung-Kwon , Smith Peter J. S. , Loeken Mary R.
Published: June 2005

We have shown that neural tube defects (NTD) in a mouse model of diabetic embryopathy are associated with deficient expression of Pax3, a gene required for neural tube closure. Hyperglycemia-induced oxidative stress is responsible. Before organogenesis, the avascular embryo is physiologically hypoxic (2–5% O2). Here we hypothesized that, because O2delivery is limited at this stage of development, excess glucose metabolism could accelerate the rate of O2consumption, thereby exacerbating the hypoxic state. Because hypoxia can increase mitochondrial superoxide production, excessive hypoxia may contribute to oxidative stress. To test this, we assayed O2flux, an indicator of O2availability, in embryos of glucose-injected hyperglycemic or saline-injected mice. O2flux was reduced by 30% in embryos of hyperglycemic mice. To test whether hypoxia replicates, and hyperoxia suppresses, the effects of maternal hyperglycemia, pregnant mice were housed in controlled O2chambers on embryonic day 7.5. Housing pregnant mice in 12% O2, or induction of maternal hyperglycemia (>250 mg/dl), decreased Pax3 expression fivefold, and increased NTD eightfold. Conversely, housing pregnant diabetic mice in 30% O2significantly suppressed the effect of maternal diabetes to increase NTD. These effects of hypoxia appear to be the result of increased production of mitochondrial superoxide, as indicated by assay of lipid peroxidation, reduced glutathione, and H2O2. Further support of this interpretation was the effect of antioxidants, which blocked the effects of maternal hypoxia, as well as hyperglycemia, on Pax3 expression and NTD. These observations suggest that maternal hyperglycemia depletes O2in the embryo and that this contributes to oxidative stress and the adverse effects of maternal hyperglycemia on embryo development.
Collecting duct-specific knockout of the endothelin A receptor alters renal vasopressin responsiveness, but not sodium excretion or blood pressure
Authors: Ge Yuqiang , Stricklett Peter K. , Hughes Alisa K. , Yanagisawa Masashi , Kohan Donald E.
Published: June 2005

Collecting duct (CD)-specific knockout (KO) of endothelin-1 (ET-1) causes hypertension, impaired ability to excrete a Na load, and enhanced CD sensitivity to the hydrosmotic effects of vasopressin (AVP). CD express the two known ET receptors, ETAand ETB; in the current study, the role of the CD ETAreceptor in mediating ET-1 actions on this nephron segment was evaluated. The ETAreceptor gene was selectively disrupted in CD (CD ETAKO). CD ETAKO mice had no differences in systemic blood pressure, Na or K excretion, and plasma aldosterone or renin activity in response to a normal- or a high-Na diet compared with controls. During normal water intake, urinary osmolality (Uosm), plasma Na concentration, and plasma osmolality were not affected, but plasma AVP concentration was increased in CD ETAKO animals (0.57 ± 0.25 pg/ml in controls and 1.30 ± 0.29 pg/ml in CD ETAKO mice). CD ETAKO mice had a modestly enhanced ability to excrete an acute, but not a chronic, water load. DDAVP infusion increased Uosm similarly; however, CD ETAKO mice had a more rapid subsequent fall in Uosm during sustained DDAVP administration. CD suspensions from CD ETAKO mice had a 30–40% reduction in AVP- and forskolin-stimulated cAMP accumulation. These data indicate that CD ETAKO decreases renal sensitivity to the urinary concentrating effects of AVP and suggest that activation of the ETAreceptor downregulates ET-1 inhibition of AVP actions in the CD. Furthermore, the CD ETAreceptor does not appear to be involved in modulation of systemic blood pressure or renal Na excretion under physiological conditions.
Nocturnal hemodialysis is associated with restoration of impaired endothelial progenitor cell biology in end-stage renal disease
Authors: Chan Christopher T. , Li Shu Hong , Verma Subodh
Published: June 2005

Cardiovascular disease is the principal cause of death in end-stage renal disease (ESRD) patients. Endothelial progenitor cells (EPCs) play a critical role in vascular repair, and improving EPC biology represents a novel therapeutic target. Three groups of age- and gender-matched patients were studied: 1) 10 healthy control, 2) 12 conventional hemodialysis (CHD) patients, and 3) 10 nocturnal hemodialysis (NHD) patients. EPC number and migratory function were assessed. Left ventricular mass index (LVMI) was derived, and correlations between EPC biology, uremic clearance, and LVMI were made. Compared with controls, EPC number and function were markedly impaired in CHD patients [(3.48 ± 1.2 vs. 0.86 ± 0.20%/50,000 cells, P < 0.05) and (18.8 ± 2.64 vs. 3.75 ± 0.34 cells/high-power field, P < 0.05), respectively]. In contrast, EPC number and function were normal in NHD patients [(3.48 ± 1.17 vs. 3.83 ± 0.77%/50,000 cells) and (18.8 ± 2.6 vs. 22.2 ± 2.4 cells/high-power field), respectively]. Among ESRD patients, EPC number and function inversely correlated with predialysis urea concentration ( r = −0.40; r = −0.57), LVMI ( r = −0.41; −0.46) and systolic BP ( r = −0.58; r = −0.44). We demonstrate that NHD is associated with restoration of abnormal EPC biology in ESRD. Given the increasing importance of EPCs in the repair and restoration of cardiovascular function, these data have important clinical implications for vascular risk in ESRD patients.
Th1 inflammatory response with altered expression of profibrotic and vasoactive mediators in AT1A and AT1B double-knockout mice
Authors: Ouyang Xiaosen , Le Thu H. , Roncal Carlos , Gersch Christine , Herrera-Acosta Jaime , Rodriguez-Iturbe Bernardo , Coffman Thomas M. , Johnson Richard J. , Mu Wei
Published: June 2005

AT1 double receptor (AT1A and AT1B) knockout mice have lower blood pressure, impaired growth, and develop early renal microvascular disease and tubulointerstitial injury. We hypothesized that there would be an increased expression of vasoactive, profibrotic, and inflammatory mediators expressed in the kidneys of AT1 double-knockout mice. We examined the renal expression of various mediator systems in control ( n = 6) vs. double-knockout mice ( n = 6) at 3–5 mo of age by real-time PCR, immunohistochemistry, and Western blot analysis. AT1 double-knockout mice show activation of Th1-dependent pathways (with increased expression of IFN-α, IL-2 mRNA) with increased expression of both monocyte (MCP-1 mRNA) and T cell (RANTES mRNA) chemokines, infiltration of CD4+ and CD11b+ cells, increased fibrosis-associated mediators (CTGF, TGF-β and TNF-α mRNA) and extracellular matrix (collagens I and III mRNA and protein) deposition compared with controls ( P < 0.05 for all markers). These changes were associated with increased mRNA expression of endothelin (ET)-1 and ET-A receptor ( P < 0.05), cyclooxygenase (COX)-2/TXA2 synthase ( P < 0.05), NADPH oxidase (p40-phox, p67-phox, P < 0.05) and iNOS and nNOS ( P < 0.05). COX-2 and nNOS protein were also increased in the kidneys of AT1 double-knockout mice by Western blot analysis ( P < 0.05). Although renin and angiotensinogen mRNA expression were increased in the knockout mice, AT2 receptor mRNA expression was not significantly different from wild-type mice. In conclusion, the absence of the AT1 receptor is associated with marked renal alterations in vasoactive, profibrotic, and immune mediators with an inflammatory pattern favoring a Th1 phenotype.
Disruption of Left–Right Reciprocal Coupling in the Spinal Cord of Larval Lamprey Abolishes Brain-Initiated Locomotor Activity
Authors: Jackson Adam W. , Horinek Dustin F. , Boyd Malinda R. , McClellan Andrew D.
Published: June 2005

In this study, contributions of left–right reciprocal coupling mediated by commissural interneurons in spinal locomotor networks to rhythmogenesis were examined in larval lamprey that had longitudinal midline lesions in the rostral spinal cord [8 → 30% body length (BL), relative distance from the head] or caudal spinal cord (30 → 50% BL). Motor activity was initiated from brain locomotor command systems in whole animals or in vitro brain/spinal cord preparations. After midline lesions in the caudal spinal cord in whole animals and in vitro preparations, left–right alternating burst activity could be initiated in rostral and usually caudal regions of spinal motor networks. In in vitro preparations, blocking synaptic transmission in the rostral cord abolished burst activity in caudal hemi-spinal cords. After midline lesions in the rostral spinal cord in whole animals, left–right alternating muscle burst activity was present in the caudal and sometimes the rostral body. After spinal cord transections at 30% BL, rhythmic burst activity usually was no longer generated by rostral hemi-spinal cords. For in vitro preparations, very slow burst activity was sometimes present in isolated right and left rostral hemi-spinal cords, but the rhythmicity for this activity appeared to originate from the brain, and the parameters of the activity were significantly different from those for normal locomotor activity. In summary, in larval lamprey under these experimental conditions, left and right hemi-spinal cords did not generate rhythmic locomotor activity in response to descending inputs from the brain, suggesting that left–right reciprocal coupling contributes to both phase control and rhythmogenesis.
Discharge of Monkey Nucleus Reticularis Tegmenti Pontis Neurons Changes During Saccade Adaptation
Authors: Takeichi N. , Kaneko C.R.S. , Fuchs A. F.
Published: May 2005

Saccade accuracy is maintained by adaptive mechanisms that continually modify saccade amplitude to reduce dysmetria. Previous studies suggest that adaptation occurs upstream of the caudal fastigial nucleus (CFN), the output of the oculomotor cerebellar vermis but downstream from the superior colliculus (SC). The nucleus reticularis tegmenti pontis (NRTP) is a major source of afferents to both the oculomotor vermis and the CFN and in turn receives direct input from the SC. Here we examine the activity of NRTP neurons in four rhesus monkeys during behaviorally induced changes in saccade amplitude to assess whether their discharge might reveal adaptation mechanisms that mediate changes in saccade amplitude. During amplitude decrease adaptation (average, 22%), the gradual reduction of saccade amplitude was accompanied by an increase in the number of spikes in the burst of 19/34 neurons (56%) and no change for 15 neurons (44%). For the neurons that increased their discharge, the additional spikes were added at the beginning of the saccadic burst and adaptation also delayed the peak-firing rate in some neurons. Moreover, after amplitude reduction, the movement fields changed shape in all 15 open field neurons tested. Our data show that saccadic amplitude reduction affects the number of spikes in the burst of more than half of NRTP neurons tested, primarily by increasing burst duration not frequency. Therefore adaptive changes in saccade amplitude are reflected already at a major input to the oculomotor cerebellum.
Cutaneous Receptors Contribute to Kinesthesia at the Index Finger, Elbow, and Knee
Authors: Collins D. F. , Refshauge K. M. , Todd G. , Gandevia S. C.
Published: May 2005

The neural mechanisms underlying the sense of joint position and movement remain controversial. While cutaneous receptors are known to contribute to kinesthesia for the fingers, the present experiments test the hypothesis that they contribute at other major joints. Illusory movements were evoked at the interphalangeal (IP) joints of the index finger, the elbow, and the knee by stimulation of populations of cutaneous and muscle spindle receptors, both separately and together. Subjects matched perceived movements with voluntary movements of homologous joints on the contralateral side. Cutaneous receptors were activated by stretch of the skin (using 2 intensities of stretch) and vibration activated muscle spindle receptors. Stimuli were designed to activate receptors that discharge during joint flexion. For the index finger, vibration was applied over the extensor tendons on the dorsum of the hand, to evoke illusory metacarpophalangeal (MCP) joint flexion, and skin stretch was delivered around the IP joints. The strong skin stretch evoked the illusion of flexion of the proximal IP joint in 6/8 subjects (12 ± 5°, mean ± SE). For the group, strong skin stretch delivered during vibration increased the perceived flexion of the proximal IP joint by eight times with a concomitant decrease in perceived flexion of the MCP joint compared with vibration alone ( P < 0.05). For the elbow, vibration was applied over the distal tendon of triceps brachii and skin stretch over the dorsal forearm. When delivered alone, strong skin stretch evoked illusory elbow flexion in 5/10 subjects (9 ± 4°). Simultaneous strong skin stretch and vibration increased the illusory elbow flexion for the group by 1.5 times compared with vibration ( P < 0.05). For the knee, vibration was applied over the patellar tendon and skin stretch over the thigh. Skin stretch alone evoked illusory knee flexion in 3/10 subjects (8 ± 4°) and when delivered during vibration, perceived knee flexion increased for the group by 1.4 times compared with vibration ( P < 0.05). Hence inputs from cutaneous receptors, muscle receptors, and combined inputs from both receptors likely subserve kinesthesia at joints throughout the body.
Long-Term Retention of Gait Stability Improvements
Authors: Bhatt T. , Pai Y.-C.
Published: June 2005

Evidence of long-term modification of behavior—in particular, gait alterations in response to repeated exposure to slips—within the locomotor-balance control system is limited. The purpose of this study was to examine whether improvements in fall-resisting behavior as reflected by improvements in gait stability could be retained on a long-term basis. Eight healthy young subjects were exposed to a block of repeated slip trials during a single acquisition session consisting of five repeated slip exposures; the same subjects were then re-tested using the same protocol at a minimum of 12 mo later. Pre- and postslip gait stability for all slip trials was measured at touchdown (slipping limb) and liftoff (contralateral limb) based on the center of mass state (i.e., its instantaneous position and velocity) relative to the base of support (BOS) and the predicted thresholds for backward loss of balance. In the acquisition session, subjects were able to increase pre- and postslip stability, which significantly correlated with a decrease in the incidence of balance loss from 100% (1st slip) to 0% (5th slip). All subjects exhibited a similar balance loss on the first slip of the follow-up session. Nonetheless, subjects were able to retain the acquired preslip stability with feedforward control on the first slip but not the postslip stability related to the reactive response. Also, the subjects demonstrated a faster re-acquisition, with only one balance loss on the second slip of the follow-up session, as compared with seven balance losses on the acquisition session. Such rapid improvements were achieved by the significantly greater increase in post- compared with preslip stability; this increase was for the most part, a consequence of reductions in slip intensity (i.e., the peak BOS velocity). We concluded that a single acquisition session could only produce limited long-term retainable effects within the locomotor-balance control system. It appeared, however, that the CNS was still primed to more rapidly update its internal representation of gait stability during re-acquisition.