bluuebunny/crossref_metadata_2025_split huggingface dataset:
A ς
54
Activator Protein Necessary for Spore Differentiation within the Fruiting Body of
Myxococcus xanthus
Authors: Gorski Lisa , Gronewold Thomas , Kaiser Dale 
Published: July 2002

ABSTRACT

Insertion of an internal DNA fragment into the
act1
gene, which encodes one of several ς
54
-activator proteins in
Myxococcus xanthus
, produced a mutant defective in fruiting body development. While fruiting-body aggregation appears normal in the mutant, it fails to sporulate (<10
−6
the wild-type number of viable spores). The A and C intercellular signals, which are required for sporulation, are produced by the mutant. But, while it produces A-factor at levels as high as that of the wild type, the mutant produces much less C-signal than normal, as measured either by C-factor bioassay or by the total amount of C-factor protein detected with specific antibody. Expression of three C-factor-dependent reporters is altered in the mutant: the level of expression of Ω4414 is about 15% of normal, and Ω4459 and Ω4403 have alterations in their time course. Finally, the methylation of FrzCD protein is below normal in the mutant. It is proposed that Act1 protein responds to C-signal reception by increasing the expression of the
csgA
gene. This C-signal-dependent increase constitutes a positive feedback in the wild type. The
act1
mutant, unable to raise the level of
csgA
expression, carries out only those developmental steps for which a low level of C-signaling is adequate.
Symbiotic Plasmid Rearrangement in
Rhizobium leguminosarum
bv. viciae VF39SM
Authors: Zhang Xue-Xian , Kosier Bob , Priefer Ursula B. 
Published: July 2002

ABSTRACT

A rearrangement between the symbiotic plasmid (pRleVF39d) and a nonsymbiotic plasmid (pRleVF39b) in
Rhizobium leguminosarum
bv. viciae VF39 was observed. The rearranged derivative showed the same plasmid profile as its parent strain, but hybridization to
nod, fix
, and
nif
genes indicated that most of the symbiotic genes were now present on a plasmid corresponding in size to pRleVF39b instead of pRleVF39d. On the other hand, some DNA fragments originating from pRleVF39b now hybridized to the plasmid band at the position of pRleVF39d. These results suggest that a reciprocal but unequal DNA exchange between the two plasmids had occurred.
Identification of a Protein That Inactivates the Competence-Stimulating Peptide of
Streptococcus pneumoniae
Authors: Bergé Mathieu , Langen Hanno , Claverys Jean-Pierre , Martin Bernard 
Published: July 2002

ABSTRACT

Competence for genetic transformation of
Streptococcus pneumoniae
is a transient physiological property inducible by a competence-stimulating peptide (CSP). A 68-kDa CSP-inactivating protein was previously obtained following lithium chloride (LiCl) extraction. By the same protocol, a CSP-inactivating protein was purified and identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry as an endopeptidase, PepO. Analysis of a
pepO
mutant provided no support for the hypothesis that PepO participates in competence regulation. To reconcile in vitro and in vivo data, we suggest that LiCl treatment results in the release of intracellular molecules, including PepO.
Comparative Performance of Herpes Simplex Virus Type 2-Specific Serologic Assays from Meridian Diagnostics and MRL Diagnostics
Authors: Ribes Julie A. , Hayes Marie , Smith Angela , Winters Jeffrey L. , Baker Doris J. 
Published: July 2002

ABSTRACT
MRL Diagnostics and Meridian Diagnostics have recently designed herpes simplex virus type 2 (HSV-2)-specific enzyme immunoassays for HSV-2 antibody detection. Blood donor sera were assayed for HSV-2 antibodies by both methods. The sensitivity, specificity, and efficiency were 97.9, 95.4, and 95.9% for the MRL assay and 83.2, 98.2, and 95.5% for the Meridian assay, respectively.
The Susceptibility of
Mycobacterium tuberculosis
to Isoniazid and the Arg→Leu Mutation at Codon 463 of
katG
Are Not Associated
Authors: van Doorn H. R. , Kuijper E. J. , van der Ende A. , Welten A. G. A. , van Soolingen D. , de Haas P. E. W. , Dankert J. 
Published: July 2002

ABSTRACT

A mutation (CCG→CTG [Arg→Leu]) in codon 463 of
katG
(catalase peroxidase) of
Mycobacterium tuberculosis
has been found in isoniazid (INH)-resistant strains. A PCR restriction endonuclease analysis to detect this mutation was applied to 395
M. tuberculosis
isolates from patients in The Netherlands. The proportion of isolates with a detectable mutation was 32% (32 out of 100) and 29% (85 out of 295) among INH-susceptible isolates and INH-resistant or -intermediate isolates, respectively. Sequencing of five INH-susceptible isolates with such mutations showed that all five had the Arg463Leu mutation. We conclude that the Arg463Leu mutation of
katG
of
M. tuberculosis
is not a reliable indicator of INH resistance.
Chlamydia pneumoniae
Serology: Importance of Methodology in Patients with Coronary Heart Disease and Healthy Individuals
Authors: Schumacher A. , Lerkerød A. B. , Seljeflot I. , Sommervoll L. , Holme I. , Otterstad J. E. , Arnesen H. 
Published: July 2002

ABSTRACT

Most publications on the relationship between infection with
Chlamydia pneumoniae
and coronary heart disease (CHD) propose an association, but negative studies are also reported. Seroepidemiological studies vary in the use of different serological methods, different cutoff limits, different sampling times in relation to acute cardiac events, and different clinical stages of CHD. We wanted to compare three different commercially available methods for measuring
Chlamydia
antibodies to see how the choice of method influenced the prevalence of seropositive individuals in CHD patients and in healthy individuals and to see if sampling time in relation to an acute cardiac event or the stage of atherothrombotic disease influenced the results. Blood samples from 197 CHD patients and 197 individually matched healthy control individuals were tested at baseline and after 6 months; the mean age was 55 years in both groups, and 18% were women. Among the CHD patients, 166 were included at a median of 16 days after an acute cardiac event and 31 had chronic disease with the latest acute event being >3 months earlier. The difference in prevalence of antibodies between the CHD patients and the healthy controls was significant when
Chlamydia
lipopolysaccharide antibodies were measured, while no significant differences between the study groups were observed by the two methods detecting
Chlamydia pneumoniae
major outer membrane protein antibodies. The number of seropositive individuals was quite similar at inclusion and 6 months later, and no significant differences were observed between patients with a recent cardiac event and those with a more remote cardiac event. We conclude that the choice of serological method is of major importance when evaluating a possible relationship between
C. pneumoniae
and CHD.
CD28 Costimulatory Blockade Exacerbates Disease Severity and Accelerates Epitope Spreading in a Virus-Induced Autoimmune Disease
Authors: Neville Katherine L. , Dal Canto Mauro C. , Bluestone Jeffrey A. , Miller Stephen D. 
Published: July 2002

ABSTRACTTheiler's murine encephalomyelitis virus (TMEV) is a natural mouse pathogen which causes a lifelong persistent infection of the central nervous system (CNS) accompanied by T-cell-mediated myelin destruction leading to chronic, progressive hind limb paralysis. TMEV-induced demyelinating disease (TMEV-IDD) is considered to be a highly relevant animal model for the human autoimmune disease multiple sclerosis (MS), which is thought to be initiated as a secondary consequence of a virus infection. Although TMEV-IDD is initiated by virus-specific CD4+T cells targeting CNS-persistent virus, CD4+T-cell responses against self myelin protein epitopes activated via epitope spreading contribute to chronic disease pathogenesis. We thus examined the ability of antibodies directed against B7 costimulatory molecules to regulate this chronic virus-induced immunopathologic process. Contrary to previous studies showing that blockade of B7-CD28 costimulatory interactions inhibit the initiation of experimental autoimmune encephalomyelitis, treatment of SJL mice at the time of TMEV infection with murine CTLA-4 immunoglobulin or a combination of anti-B7-1 and anti-B7-2 antibodies significantly enhanced clinical disease severity. Costimulatory blockade inhibited early TMEV-specific T-cell and antibody responses critical in clearing peripheral virus infection. The inhibition of virus-specific immune responses led to significantly increased CNS viral titers resulting in increased damage to myelin-producing oligodendrocytes. Following clearance of the costimulatory antagonists, epitope spreading to myelin epitopes was accelerated as a result of the increased availability of myelin epitopes leading to a more severe chronic disease course. Our results raise concern about the potential use of B7-CD28 costimulatory blockade to treat human autoimmune diseases potentially associated with acute or persistent virus infections.
Human Immunodeficiency Virus Type 1 Envelope Epitope-Specific CD4+T Lymphocytes in Simian/Human Immunodeficiency Virus-Infected and Vaccinated Rhesus Monkeys Detected Using a Peptide-Major Histocompatibility Complex Class II Tetramer
Authors: Kuroda Marcelo J. , Schmitz Jörn E. , Lekutis Christine , Nickerson Christine E. , Lifton Michelle A. , Franchini Genoveffa , Harouse Janet M. , Cheng-Mayer Cecilia , Letvin Norman L. 
Published: July 2002

ABSTRACTA tetrameric recombinant major histocompatibility complex (MHC) class II-peptide complex was used to quantitate human immunodeficiency virus type 1 (HIV-1) envelope (Env)-specific CD4+T cells in vaccinated and in simian/human immunodeficiency virus (SHIV)-infected rhesus monkeys. A rhesus monkey MHC class II DR molecule, Mamu-DR*W201, and an HIV-1 Env peptide (p46) were employed to construct this tetrameric complex. A p46-specific proliferative response was seen in sorted, tetramer-binding, but not nonbinding, CD4+T cells, directly demonstrating that this response was mediated by the epitope-specific lymphocytes. Although staining of whole blood from 10 SHIV-infectedMamu-DR*W201+rhesus monkeys failed to demonstrate tetramer-binding CD4+T cells (<0.02%), p46-stimulated peripheral blood mononuclear cells (PBMCs) from 9 of these 10 monkeys had detectable p46 tetramer-binding cells, comprising 0.5 to 15.2% of the CD4+T cells. p46-stimulated PBMCs from 7 of 10 Mamu-DR*W201+monkeys vaccinated with a recombinant canarypox virus–HIV-1envconstruct also demonstrated p46 tetramer-binding cells, comprising 0.9 to 7.2% of the CD4+T cells. Thus, Env p46-specific CD4+T cells can be detected by tetrameric Mamu-DR*W201–p46 complex staining of PBMCs in both SHIV-infected and vaccinated rhesus monkeys. These epitope-specific cell populations appear to be present in peripheral blood at a very low frequency.
Functional Mapping of Protective Domains and Epitopes in the Rotavirus VP6 Protein
Authors: Choi Anthony H. C. , Basu Mitali , McNeal Monica M. , Flint Jason , VanCott John L. , Clements John D. , Ward Richard L. 
Published: July 2002

ABSTRACTThe purpose of this study was to determine which regions of the VP6 protein of the murine rotavirus strain EDIM are able to elicit protection against rotavirus shedding in the adult mouse model following intranasal (i.n.) immunization with fragments of VP6 and a subsequent oral EDIM challenge. In the initial experiment, the first (fragment AB), middle (BC), or last (CD) part of VP6 that was genetically fused to maltose-binding protein (MBP) and expressed inEscherichia coliwas examined. Mice (BALB/c) immunized with two 9-μg doses of each of the chimeras and 10 μg of the mucosal adjuvant LT(R192G) were found to be protected against EDIM shedding (80, 92, and nearly 100% reduction, respectively;P≤ 0.01) following challenge. Because CD produced almost complete protection, we prepared fourE. coli-expressed, MBP-fused chimeras containing overlapping fragments of the CD region (i.e., CD1, CD2, CD3, and CD4) whose lengths ranged from 61 to 67 amino acid residues. Following i.n. immunization, CD1, CD2, and CD4 induced significant (P≤ 0.004) protection (88, 84, and 92% reduction, respectively). In addition, 11 peptides (18 to 30 residues) of the CD region with between 0 and 13 overlapping amino acids were synthesized. Two 50-μg doses of each peptide with LT(R192G) were administered i.n. to BALB/c mice. Five peptides were found to elicit significant (P≤ 0.02) protection. Moreover, a 14-amino-acid region within peptide 6 containing a putative CD4+T-cell epitope was found to confer nearly complete protection, suggesting a protective role for CD4+T cells. Mice that were protected by fragments BC and CD1 and four of the five protective synthetic peptides did not develop measurable rotavirus antibodies in serum or stool, implying that protection induced by these domains was not dependent on antibody. Together, these observations suggest that multiple regions of VP6 can stimulate protection, a region of VP6 as small as 14 amino acids containing a CD4+T-cell epitope can stimulate nearly complete protection, and protection mediated by a subset of epitopes in the VP6 protein does not require antibodies in BALB/c mice.
Processing and Presentation of Murine Cytomegalovirus pORFm164-Derived Peptide in Fibroblasts in the Face of All Viral Immunosubversive Early Gene Functions
Authors: Holtappels Rafaela , Grzimek Natascha K. A. , Simon Christian O. , Thomas Doris , Dreis Doris , Reddehase Matthias J. 
Published: July 2002

ABSTRACTCD8 T cells are the principal effector cells in the resolution of acute murine cytomegalovirus (mCMV) infection in host organs. This undoubted antiviral and protective in vivo function of CD8 T cells appeared to be inconsistent with immunosubversive strategies of the virus effected by early (E)-phase genesm04,m06, andm152. The so-called immune evasion proteins gp34, gp48, and gp37/40, respectively, were found to interfere with peptide presentation at different steps in the major histocompatibility complex (MHC) class I pathway of antigen processing and presentation in fibroblasts. Accordingly, they were proposed to prevent recognition and lysis of infected fibroblasts by cytolytic T lymphocytes (CTL) during the E phase of viral gene expression. We document here that the previously identified MHC class I Dd-restricted antigenic peptide257AGPPRYSRI265encoded by genem164is processed as well as presented for recognition by m164-specific CTL during the E and late phases of viral replication in the very same cells in which the immunosubversive viral proteins are effectual in preventing the presentation of processed immediate-early 1 (m123-exon 4) peptide168YPHFMPTNL176. Thus, while immunosubversion is a reality, these mechanisms are apparently not as efficient as the term immune evasion implies. The pORFm164-derived peptide is the first noted peptide that constitutively escapes the immunosubversive viral functions. The most important consequence is that even the concerted action of all immunosubversive E-phase proteins eventually fails to prevent immune recognition in the E phase. The bottom-line message is that there exists no immune evasion of mCMV in fibroblasts.
Bile bilirubin pigment analysis in disorders of bilirubin metabolism in early infancy
Authors: Lee W S , McKiernan P J , Beath S V , Preece M A , Baty D , Kelly D A , Burchell B , Clarke D J 
Published: July 2002

BACKGROUNDEarly and accurate diagnosis of Crigler–Najjar syndrome, which causes prolonged unconjugated hyperbilirubinaemia in infancy, is important, as orthotopic liver transplantation is the definitive treatment.AIMTo determine whether bilirubin pigment analysis of bile in infants with prolonged unconjugated hyperbilirubinaemia provides useful diagnostic information in the first 3 months of life.METHODSRetrospective review of patients with prolonged unconjugated hyperbilirubinaemia referred to the liver unit, Birmingham Children's Hospital, for the diagnosis of Crigler–Najjar syndrome. Bile bilirubin pigment composition was determined by high performance liquid chromatography. Initial diagnoses were made based on the result of bile bilirubin pigment composition. Final diagnoses were made after reviewing the clinical course, response to phenobarbitone, repeat bile bilirubin pigment composition analysis, and genetic studies.RESULTSBetween 1992 and 1999, nine infants aged less than 3 months of age with prolonged hyperbilirubinaemia underwent bile bilirubin pigment analyses. Based on these, two children were diagnosed with Crigler–Najjar syndrome (CNS) type 1, six with CNS type 2, and one with Gilbert's syndrome. Five children whose initial diagnosis was CNS type 2 had resolution of jaundice and normalisation of serum bilirubin after discontinuing phenobarbitone, and these cases were thought to be normal or to have Gilbert's syndrome. One of the initial cases of CNS type 1 responded to phenobarbitone with an 80% reduction in serum bilirubin consistent with CNS type 2. In all, the diagnoses of six cases needed to be reviewed.CONCLUSIONSEarly bile pigment analysis, performed during the first 3 months of life, often shows high levels of unconjugated bilirubin or bilirubin monoconjugates, leading to the incorrect diagnosis of both type 1 and type 2 Crigler–Najjar syndrome.
RELATIVE TORSION
Authors: BURGHELEA DAN , FRIEDLANDER LEONID , KAPPELER THOMAS 
Published: July 2002

This paper achieves, among other things, the following: • It frees the main result of [9] from the hypothesis of determinant class and extends this result from unitary to arbitrary representations. • It extends (and at the same times provides a new proof of) the main result of Bismut and Zhang [3] from finite dimensional representations of Γ to representations on an [Formula: see text]-Hilbert module of finite type ([Formula: see text] a finite von Neumann algebra). The result of [3] corresponds to [Formula: see text]. • It provides interesting real valued functions on the space of representations of the fundamental group Γ of a closed manifold M. These functions might be a useful source of topological and geometric invariants of M. These objectives are achieved with the help of the relative torsion ℛ, first introduced by Carey, Mathai and Mishchenko [12] in special cases. The main result of this paper calculates explicitly this relative torsion (cf. Theorem 1.1).
Parallel logic simulation of VLSI systems
Authors: Bailey Mary L. , Briner Jack V. , Chamberlain Roger D. 
Published: July 2002

Fast, efficient logic simulators are an essential tool in modern VLSI system design. Logic simulation is used extensively for design verification prior to fabrication, and as VLSI systems grow in size, the execution time required by simulation is becoming more and more significant. Faster logic simulators will have an appreciable economic impact, speeding time to market while ensuring more thorough system design testing. One approach to this problem is to utilize parallel processing, taking advantage of the concurrency available in the VLSI system to accelerate the logic simulation task.
Parallel logic simulation has received a great deal of attention over the past several years, but this work has not yet resulted in effective, high-performance simulators being available to VLSI designers. A number of techniques have been developed to investigate performance issues: formal models, performance modeling, empirical studies, and prototype implementations. Analyzing reported results of these techniques, we conclude that five major factors affect performance: synchronization algorithm, circuit structure, timing granularity, target architecture, and partitioning. After reviewing techniques for parallel simulation, we consider each of these factors using results reported in the literature. Finally we synthesize the results and present directions for future research in the field.
Shading models for point and linear sources
Authors: Nishita Tomoyuki , Okamura Isao , Nakamae Eihachiro 
Published: July 2002

The degree of realism of the shaded image of a tree-dimensional scene depends on the successful simulation of shading effects. The shading model has two main ingredients, properties of the surface and properties of the illumination falling on it. Most previous work has concentrated on the former rather than the latter.
This paper presents an improved version for generating scenes illuminated by point and linear light sources. The procedure can include intensity distributions for point light sources and output both umbrae and penumbrae for linear light sources, assuming thr environment is composed of convex polyhedra. This paper generalizes Crow's procedure for computing shadow volumes caused by the end points of the linear source results in an easy determination of the reions of penumbrae and umbrae on the face prior to shading calculation.
This paper also discusses a method for displaying illuminance distribution on a shaded image aby using colored isolux contours.
Matrix Inversion Using Parallel Processing
Authors: Pease Marshall C. 
Published: July 2002

Two general methods of matrix inversion, Gauss's algorithm and the method of bordering, are analyzed from the viewpoint of their adaptability for parallel computation. The analysis is not based on any specific type of parallel processor; its purpose is rather to see if parallel capabilities could be used effectively in matrix inversion.
It is shown that both methods are indeed able to make effective use of parallel capability. With reasonable assumptions on the parallelism that is available, the speeds of the two methods are roughly comparable. The two methods, however, make use of different kinds of parallelism.

To implement Gauss's algorithm we would like to have (a) parallel transfer capability for
n
numbers, if the matrix is
n
X
n
, (b) the capability for parallel multiplication of the accessed numbers by a common multiplier, and (c) parallel additive read-in capability. For the method of bordering, we need, primarily, the capability of forming the Euclidean inner product of two
n
-dimensional real vectors. The latter seems somewhat harder to implement, but, because it is an operation that is fundamental to linear algebra in general, it is one that might be made available for other purposes. If so, then the method of bordering becomes of interest.
Two remarks on Tau-splines
Authors: Lasser Dieter 
Published: July 2002

We present a Bézier representation of τ-splines, curvature and torsion-continuous quintics, which were introduced in CAGD by Hagen in 1985 [32]. Explicit formulas are given for the conversion from Bézier representation to τ-spline representation, and vice versa. Thus, by embedding the Bézier representation in a Β-spline representation of curvature and torsion-continuous quintic spline curves, given in [20], a Β-spline-Bézier representation of τ-splines results.
Second, positivity conditions for the design parameters of the Bézier representation and certain ranges of tension values are derived, which ensure properties like the convex hull and the variation-diminishing property of the Β-spline-Bézier representation.
Design's Own Knowledge
Authors: Narváez Luz María Jiménez 
Published: July 2002

Doxa: from the Greek, opinion, way of thinking. According to Parmenides, the world of doxa was the world of the opinions of mortals. When substituted by “what is” for what seems to be, or when mortals concur to manipulate things, or understand themselves, it becomes a falsehood or an error. Husserl held that all expressions are a doxic act in their full sense, i.e, a certainty, a belief. 1 1 Paul Foulquie, Diccionario del lenguaje filosófico (Barcelona: Editorial Labor, 1962), 42.