bluuebunny/crossref_metadata_2025 huggingface dataset:
Drug Stories--of Origins and Uses
Authors: Enna S. J.
Published: July 2002

Pills, Potions and Poisons
How Drugs Work. Trevor Stone and Gail Darlington. Oxford University Press, New York, 2000. 492 pp. $27.50, £18.99. ISBN 0-19-850403-9.

Stone and Darlington provide a non-technical survey of how chemicals act in the body. Their chapters on major groups of medicines (organized around common disorders from allergies to schizophrenia), recreational drugs, and animal venoms are leavened with anecdotes on the people and research behind the discovery of various drugs.
Viscosity Mechanisms in Accretion Disks
Authors: Menou Kristen
Published: July 2002

The self-sustained turbulence that develops in magnetized accretion disks is suppressed in the weakly ionized, quiescent disks of close binary stars. Because accretion still proceeds during quiescence, another viscosity mechanism operates in these systems. An anticorrelation of the recurrence times of SU UMa dwarf novae with their mass ratio supports spiral waves or shockwaves tidally induced by the companion star as the main process responsible for accretion in the quiescent disks. Other weakly ionized gaseous disks in systems lacking a massive companion must rely on yet another transport mechanism, or they could be essentially passive.
Battlefield Sociobiology
Authors: Jolly Alison
Published: July 2002

Defenders of the Truth
The Battle for Science in the Sociobiology Debate and Beyond. Ullica Segerstråle. Oxford University Press, New York, 2000. 503 pp. $35, £18.99. ISBN 0-19-850505-1.

In this book for scientists and students of science, Segerstråle blends a blow-by-blow account of the disputes over sociobiology with a multi-level analysis of its context and components.
Nota Bene: Frozen Moments
Authors: Voss David
Published: July 2002

Exploring the Art and Science of Stopping Time
The Life and Work of Harold E. Edgerton. Produced by James Sheldon. MIT Press, Cambridge, MA, 1999. CD-ROM for Windows and Macintosh. $37.95, £23.50. ISBN 0-262-55031-8.

This CD-ROM provides a fascinating introduction to the life, images, and techniques of the inventor who developed strobe photography.
Quantum Hall Ferromagnetism in a Two-Dimensional Electron System
Authors: Eom J. , Cho H. , Kang W. , Campman K. L. , Gossard A. C. , Bichler M. , Wegscheider W.
Published: July 2002

Experiments on a nearly spin degenerate two-dimensional electron system reveals unusual hysteretic and relaxational transport in the fractional quantum Hall effect regime. The transition between the spin-polarized (with fill fraction ν = 1/3) and spin-unpolarized (ν = 2/5) states is accompanied by a complicated series of hysteresis loops reminiscent of a classical ferromagnet. In correlation with the hysteresis, magnetoresistance can either grow or decay logarithmically in time with remarkable persistence and does not saturate. In contrast to the established models of relaxation, the relaxation rate exhibits an anomalous divergence as temperature is reduced. These results indicate the presence of novel two-dimensional ferromagnetism with a complicated magnetic domain dynamic.
Blue Book Value
Authors: Berenbaum May
Published: July 2002

Nabokov's Blues
The Scientific Odyssey of a Literary Genius. Kurt Johnson and Steve Coates. Zoland, Cambridge, MA, 1999. 384 pp. $27. C$38. ISBN 1-58195-009-8.

Nabokov's Butterflies
Unpublished and Uncollected Writings. Brian Boyd and Robert Michael Pyle, Eds. Beacon, Boston, 2000. 796 pp. $45. ISBN 0-8070-8540-5. Allen Lane, London, 2000. 796 pp. £25. ISBN 0-7139-9380-4.

These two volumes celebrate the lepidopteran obsession of writer Vladimir Nabokov. Boyd and Pyle offer a collection of Nabokov's writings, fictional and scientific, to document the connections between the insects and Nabokov's art. Johnson and Coates focus on the novelist's work on a diverse group of Andean butterflies.
A Fondness for "Beetles of the Paleozoic"
Authors: Palmer Allison R.
Published: July 2002

Trilobite!
Eyewitness to Evolution. Richard Fortey. Harper Collins, London, 2000. 283 pp. £15.99. ISBN 0-00-257012-2. Knopf, New York, 2000. 288 pp. $26. ISBN 0-375-40625-5 (available 31 October).

Fortey's accounts of trilobites, their geological and biological significance, and trilobite workers past and present will appeal to readers with any level of interest in or experience with these fossils.
Lessons from Chaco Canyon
Authors: Adler Michael
Published: July 2002

Anasazi America
Seventeen Centuries on the Road from Center Place. David E. Stuart. University of New Mexico Press, Albuquerque, 2000. 265 pp. $29.95. ISBN 0-8263-2178-X. Paper, $15.95. ISBN 0-8263-2179-8.

In this narrative account of the gradual rise and rapid decline of the Chaco Anasazi, Stuart highlights the potential implications for modern societies of the contrasting fates of the Anasazi and their Pueblo descendants.
On E. O. Wilson and His Religious Vision
Authors: Ruse Michael
Published: July 2002

Life is a Miracle
An Essay Against Modern Superstition. Wendell Berry. Counterpoint, Washington, DC, 2000. 163 pp. $21. ISBN 1-58243-058-6.

In part provoked by E. O. Wilson's claims in
Consilience
, Berry argues that religion and the arts cannot be contained within the boundaries of modern science or understood through its materialistic and reductionistic assumptions. Our reviewer suggests that Wilson is not Berry's real enemy and that their shared concerns about the way we live and treat our planet might more effectively be addressed by cooperation.
Learning by Text or Context?
Authors: Schatz Bruce R.
Published: July 2002

The Social Life of Information
. John Seely Brown and Paul Duguid. Harvard Business School Press, Boston, 2000. 332 pp. $25.95. ISBN 0-87584-762-5.

Focusing on the social contexts in which individuals and information function, Brown and Duguid offer a balanced yet critical examination of the widespread view that the Net will remake the world.
Attending Marvels
Authors: Eldredge Niles
Published: July 2002

George Gaylord Simpson
Paleontologist and Evolutionist. Léo F. Laporte. Columbia University Press, New York, 2000. 350 pp. $50, £32. ISBN 0-231-12064-8. Paper, $16, £10.50. ISBN 0-231-12065-6.

In lieu of a biography of Simpson (who is best known for his substantial contributions to evolutionary biology's "modern synthesis"), Laporte offers an intellectual study that is focused on the major areas of his subject's research.
Resonance-Enhanced Two-Photon Ionization of Ions by Lyman α Radiation in Gaseous Nebulae
Authors: Johansson Sveneric , Letokhov Vladilen
Published: July 2002

One of the mysteries of nebulae in the vicinity of bright stars is the appearance of bright emission spectral lines of ions, which imply fairly high excitation temperatures. We suggest that an ion formation mechanism, based on resonance-enhanced two-photon ionization (RETPI) by intense H Lyman α radiation (wavelength of 1215 angstroms) trapped inside optically thick nebulae, can produce these spectral lines. The rate of such an ionization process is high enough for rarefied gaseous media where the recombination rate of the ions formed can be 10
−6
to 10
−8
per second for an electron density of 10
3
to 10
5
per cubic centimeter in the nebula. Under such conditions, the photo-ions formed may subsequently undergo further RETPI, catalyzed by intense He
i
and He
ii
radiation, which also gets enhanced in optically thick nebulae that contain enough helium.
Presence of Variations in Ribosomal Protein L16 Corresponding to Susceptibility of Enterococci to Oligosaccharides (Avilamycin and Evernimicin)
Authors: Aarestrup Frank Møller , Jensen Lars Bogø
Published: July 2002

Fragments (414 bp) of the gene-encoding ribosomal protein L16 from
Enterococcus faecium
and
Enterococcus faecalis
that were resistant and susceptible to the oligosaccharide antibiotics avilamycin and evernimicin (SCH 27899) were sequenced and compared. The susceptible
E. faecalis
and
E. faecium
isolates had sequences that were similar to those of the type strains. All resistant
E. faecalis
isolates contained the same base pair variation [CGT (Arg-56) → CAT (His-56)]. The same variation and two additional variations [ATC (Ile-52) → ACC (Thr-52) and ATC (Ile-52) → AGC (Ser-52)] were found in the resistant
E. faecium
isolates. This study indicated that resistance to the oligosaccharides in enterococci is associated with variations in the ribosomal protein L16.
Susceptibilities of
Corynebacterium bovis
and
Corynebacterium amylocolatum
Isolates from Bovine Mammary Glands to 15 Antimicrobial Agents
Authors: Watts Jeffrey L. , Rossbach Silvia
Published: July 2002

Coryneform bacteria are frequently isolated from bovine mastitis and are associated with economic losses. Generally, the MICs of the 15 antimicrobial agents tested at which 90% of the isolates tested are inhibited for 46
Corynebacterium bovis
and 13
Corynebacterium amylocolatum
strains were low. These are the first quantitative antimicrobial susceptibility data available for coryneforms from bovine mastitis. Data from this study suggest that comparable corynebacteria from humans have a much higher level of antimicrobial resistance to a variety of antimicrobial agents.
Anaerobic Toluene Activation by Benzylsuccinate Synthase in a Highly Enriched Methanogenic Culture
Authors: Beller Harry R. , Edwards Elizabeth A.
Published: July 2002

Permeabilized cells of a highly enriched, toluene-mineralizing, methanogenic culture catalyzed the addition of toluene to fumarate to form benzylsuccinate under anaerobic conditions. The specific in vitro rate of benzylsuccinate formation was >85% of the specific in vivo rate of toluene consumption. This is the first report of benzylsuccinate synthase activity in a methanogenic culture; the activity has previously been reported to occur in denitrifying, sulfate-reducing, and anoxygenic phototrophic bacteria.
Neisseria meningitidis
Expressing Transferrin Binding Proteins of
Actinobacillus pleuropneumoniae
Can Utilize Porcine Transferrin for Growth
Authors: Litt David J. , Palmer Helen M. , Borriello S. Peter
Published: July 2002

Homologous recombination was used to generate a number of mutants of serogroup B
Neisseria meningitidis
B16B6 with the following characteristics: (i) an inability to bind human or porcine transferrin because of loss of both transferrin binding proteins (Tbp) A and B [strain B16B6(Str
r
)/tbpA
−
B
−
] and (ii) an ability to bind porcine transferrin but not human transferrin [strain B16B6(Str
r
)/tbpA
ap
B
ap
] due to replacement of the meningococcal Tbp with the Tbp of
Actinobacillus pleuropneumoniae
. During construction of the B16B6(Str
r
)/tbpA
ap
B
ap
strain, transformants expressing only TbpA or TbpB of
A. pleuropneumoniae
were isolated [strains B16B6(Str
r
)/tbpA
ap
B
−
and B16B6(Str
r
)/tbpA
−
B
ap
]. Expression of the
A. pleuropneumoniae
Tbp in
N. meningitidis
B16B6 was iron regulated and expressed under the control of the meningococcal promoter. The relative abilities of the meningococcal transformants to bind porcine transferrin were in the order B16B6(Str
r
)/tbpA
ap
B
ap
> B16B6(Str
r
)/tbpA
ap
B
−
> B16B6(Str
r
)/tbpA
−
B
ap
. Of these transformants, only B16B6(Str
r
)/tbpA
ap
B
ap
could grow in the presence of porcine transferrin as the sole iron source, achieving a growth rate similar to that of the B16B6 parent strain in the presence of human transferrin.
Conservation and Heterogeneity of
vlsE
among Human and Tick Isolates of
Borrelia burgdorferi
Authors: Iyer Radha , Hardham John M. , Wormser Gary P. , Schwartz Ira , Norris Steven J.
Published: July 2002

The
vls
(variable major protein [VMP]-like sequence) locus of
Borrelia burgdorferi
encodes an antigenic variation system that closely resembles the VMP system of relapsing fever borreliae. To determine whether
vls
sequences are present consistently in low-passage, infectious isolates of
B. burgdorferi
, 22 blood and erythema migrans biopsy isolates from Lyme disease patients in Westchester County, New York, were examined by Southern blot and PCR analysis. Each of the strains contained a single plasmid varying in size from 21 to 38 kb that hybridized strongly with a
vlsE
probe based on the
B. burgdorferi
B31 sequence. In contrast, PCR products were obtained with only 10 of the 22 strains when primers corresponding to the 5′ and 3′ regions of the B31
vlsE
sequence outside the variable cassette region were used. Only 2 of 16
B. burgdorferi
-infected tick specimens yielded detectable PCR product. Eight of 10 strains that yielded a PCR product under these conditions were type 1 (a genotype with a high rate of dissemination), according to PCR-restriction fragment length polymorphism analysis of intergenic rDNA sequences, whereas the isolates that did not yield
vlsE
PCR products were either type 2 or type 3. Comparison of the sequences of cloned PCR products from the patient isolates indicated a high degree of identity to the B31 sequence, with most of the differences restricted to the hypervariable regions known to undergo sequence variation. Taken together, these results both reinforce previous evidence that
vls
sequences are present consistently in low-passage Lyme disease spirochetes and indicate that both highly conserved and heterogeneous subgroups exist with regard to
vlsE
sequences.
Purified Lipopolysaccharide fromFrancisella tularensisLive Vaccine Strain (LVS) Induces Protective Immunity against LVS Infection That Requires B Cells and Gamma Interferon
Authors: Dreisbach Valley C. , Cowley Siobhan , Elkins Karen L.
Published: July 2002

Previous results have demonstrated that nonspecific protective immunity against lethalFrancisella tularensislive vaccine strain (LVS) orListeria monocytogenesinfection can be stimulated either by sublethal infection with bacteria or by treatment with bacterial DNA given 3 days before lethal challenge. Here we characterize the ability of purified lipopolysaccharide (LPS) fromF. tularensisLVS to stimulate similar early protective immunity. Treatment of mice with surprisingly small amounts of LVS LPS resulted in very strong and long-lived protection against lethal LVS challenge within 2 to 3 days. Despite this strong protective response, LPS purified fromF. tularensisLVS did not activate murine B cells for proliferation or polyclonal immunoglobulin secretion, nor did it activate murine splenocytes for secretion of interleukin-4 (IL-4), IL-6, IL-12, or gamma interferon (IFN-γ). Immunization of mice with purified LVS LPS induced a weak specific anti-LPS immunoglobulin M (IgM) response and very little IgG; however, infection of mice with LVS bacteria resulted in vigorous IgM and IgG, particularly IgG2a, anti-LPS antibody responses. Studies using various immunodeficient mouse strains, including LPS-hyporesponsive C3H/HeJ mice, μMT−(B-cell-deficient) knockout mice, and IFN-γ-deficient mice, demonstrated that the mechanism of protection does not involve recognition through theLpsngene product; nonetheless, protection was dependent on B cells as well as IFN-γ.
Antioxidant Enzyme Expression in Clinical Isolates of
Pseudomonas aeruginosa
: Identification of an Atypical Form of Manganese Superoxide Dismutase
Authors: Britigan Bradley E. , Miller Rachel A. , Hassett Daniel J. , Pfaller Michael A. , McCormick Michael L. , Rasmussen George T.
Published: July 2002

Expression of superoxide dismutases (FeSOD and MnSOD) and catalases by laboratory strains of
Pseudomonas aeruginosa
is modulated by exogenous factors. Whether clinical isolates behave similarly and whether antioxidant enzyme expression influences
P. aeruginosa
virulence remain unclear. Fifty-seven
P. aeruginosa
blood culture isolates, plus seven pairs of blood and local-site isolates, were examined for FeSOD, MnSOD, and catalase production in vitro. Under iron-replete growth conditions FeSOD and catalase activities were maximized. MnSOD was not detected. FeSOD and catalase activity decreased under iron-limited growth conditions, whereas MnSOD activity appeared. SOD and catalase activity did not change with site of isolation or by patient. MnSOD could not be expressed by one isolate due to a missense mutation in
sodA
that produced a premature stop codon. Eleven percent of the isolates expressed a novel, rapidly migrating MnSOD that was associated with missense mutations in the normal stop codon of
sodA
. We conclude that clinical
P. aeruginosa
isolates vary little in FeSOD and catalase expression. Some strains produce a newly described MnSOD variant, whereas one is deficient in MnSOD production. The absence of MnSOD expression in a
P. aeruginosa
strain causing invasive human disease indicates that MnSOD is probably not essential for
P. aeruginosa
virulence.
Discovery, Purification, and Characterization of a Temperate Transducing Bacteriophage for
Bordetella avium
Authors: Shelton Celia B. , Crosslin David R. , Casey Jennifer L. , Ng S. , Temple Louise M. , Orndorff Paul E.
Published: July 2002

We discovered and characterized a temperate transducing bacteriophage (Ba1) for the avian respiratory pathogen
Bordetella avium
. Ba1 was initially identified along with one other phage (Ba2) following screening of four strains of
B. avium
for lysogeny. Of the two phage, only Ba1 showed the ability to transduce via an allelic replacement mechanism and was studied further. With regard to host range, Ba1 grew on six of nine clinical isolates of
B. avium
but failed to grow on any tested strains of
Bordetella bronchiseptica
,
Bordetella hinzii
,
Bordetella pertussis
, or
Bordetella parapertussis
. Ba1 was purified by CsCl gradient centrifugation and was found to have an icosahedral head that contained a linear genome of approximately 46.5 kb (contour length) of double-stranded DNA and a contractile, sheathed tail. Ba1 readily lysogenized our laboratory
B. avium
strain (197N), and the prophage state was stable for at least 25 generations in the absence of external infection. DNA hybridization studies indicated the prophage was integrated at a preferred site on both the host and phage replicons. Ba1 transduced five distinctly different insertion mutations, suggesting that transduction was generalized. Transduction frequencies ranged from approximately 2 × 10
−7
to 1 × 10
−8
transductants/PFU depending upon the marker being transduced. UV irradiation of transducing lysates markedly improved transduction frequency and reduced the number of transductants that were lysogenized during the transduction process. Ba1 may prove to be a useful genetic tool for studying
B. avium
virulence factors.
Effects of Specific Amino Acid Substitutions on Activities of Dinitrogenase Reductase-Activating Glycohydrolase from
Rhodospirillum rubrum
Authors: Antharavally Babu S. , Poyner Russell R. , Zhang Yaoping , Roberts Gary P. , Ludden Paul W.
Published: July 2002

Site-directed mutagenesis of the
draG
gene was used to generate altered forms of dinitrogenase reductase-activating glycohydrolase (DRAG) with D123A, H142L, H158N, D243G, and E279R substitutions. The amino acid residues H142 and E279 are not required either for the coordination to the metal center or for catalysis since the variants H142L and E279R retained both catalytic and electron paramagnetic resonance spectral properties similar to those of the wild-type enzyme. Since DRAG-H158N and DRAG-D243G variants lost their ability to bind Mn(II) and to catalyze the hydrolysis of the substrate, H158 and D243 residues could be involved in the coordination of the binuclear Mn(II) center in DRAG.
Effect of P
II
and Its Homolog GlnK on Reversible ADP-Ribosylation of Dinitrogenase Reductase by Heterologous Expression of the
Rhodospirillum rubrum
Dinitrogenase Reductase ADP-Ribosyl Transferase–Dinitrogenase Reductase-Activating Glycohydrolase Regulatory System in
Klebsiella pneumoniae
Authors: Zhang Yaoping , Pohlmann Edward L. , Halbleib Cale M. , Ludden Paul W. , Roberts Gary P.
Published: July 2002

Reversible ADP-ribosylation of dinitrogenase reductase, catalyzed by the dinitrogenase reductase ADP-ribosyl transferase–dinitrogenase reductase-activating glycohydrolase (DRAT-DRAG) regulatory system, has been characterized in
Rhodospirillum rubrum
and other nitrogen-fixing bacteria. To investigate the mechanisms for the regulation of DRAT and DRAG activities, we studied the heterologous expression of
R. rubrum draTG
in
Klebsiella pneumoniae glnB
and
glnK
mutants. In
K. pneumoniae
wild type, the regulation of both DRAT and DRAG activity appears to be comparable to that seen in
R. rubrum
. However, the regulation of both DRAT and DRAG activities is altered in a
glnB
background. Some DRAT escapes regulation and becomes active under N-limiting conditions. The regulation of DRAG activity is also altered in a
glnB
mutant, with DRAG being inactivated more slowly in response to NH
4
+
treatment than is seen in wild type, resulting in a high residual nitrogenase activity. In a
glnK
background, the regulation of DRAT activity is similar to that seen in wild type. However, the regulation of DRAG activity is completely abolished in the
glnK
mutant; DRAG remains active even after NH
4
+
addition, so there is no loss of nitrogenase activity. The results with this heterologous expression system have implications for DRAT-DRAG regulation in
R. rubrum
.
Two “Wild-Type” Variants of
Escherichia coli
σ
70
: Context-Dependent Effects of the Identity of Amino Acid 149
Authors: Baldwin Nicole E. , McCracken Andrea , Dombroski Alicia J.
Published: July 2002

The identity of amino acid 149 of
Escherichia coli
σ
70
has been reported variably as either arginine or aspartic acid. We show that the behavior of both a region 1.2 deletion and a single-amino-acid substitution at position 122 are greatly affected by the identity of amino acid 149.
Characteristics of
Helicobacter pylori
Infection in Jamaican Adults with Gastrointestinal Symptoms
Authors: Hisada Michie , Lee Michael G. , Hanchard Barrie , Owens Marilyn , Song Qunsheng , van Doorn Leen-Jan , Cutler Alan F. , Gold Benjamin D.
Published: July 2002

Helicobacter pylori
infection is common in Jamaica. Describing its epidemiology in a population-based study depends largely on serology, but serologic assays have not been validated in this population. To address this issue, we examined the presence of
H. pylori
infection in 30 sequential adult patients with gastroduodenal symptoms by three biopsy-based methods (rapid urease test, histology, and culture) as well as by one research and two commercial enzyme-linked immunosorbent assays (ELISAs). A patient was considered
H. pylori
positive if the organism was detected by at least one biopsy-based method. Eighteen (60%) of the 30 patients were
H. pylori
positive by these criteria, whereas 21 (70%) were seropositive for
H. pylori
immunoglobulin G by our research ELISA. The presence of
H. pylori
infection in patients with gastric cancer and those with chronic gastritis was missed by biopsy-based methods but was detected by serologic assays. This observation indicates that serologic assays may be better suited for the detection of this infection in a population in which
H. pylori
-associated pathology is prevalent. The performance of our research ELISA in detecting biopsy-based
H. pylori
-positive cases was excellent, with a sensitivity and specificity of 100% and 75%, respectively. Molecular genotyping of the isolates revealed that the predominant
H. pylori
genotypes in this cohort of Jamaicans were

cagA
+
vacA

slb-m1, and
iceA2
. The validated serologic assay enables us to interpret epidemiologic data from population-based studies in Jamaica by comparison to those from other populations.
Comparative Quantitation of Cytomegalovirus (CMV) DNA in Solid Organ Transplant Recipients with CMV Infection by Using Two High-Throughput Automated Systems
Authors: Razonable Raymund R. , Brown Robert A. , Espy Mark J. , Rivero Antonio , Kremers Walter , Wilson Jennie , Groettum Cynthia , Smith Thomas F. , Paya Carlos V.
Published: July 2002

Cytomegalovirus (CMV) DNA quantitation in clinical specimens is progressively becoming a cornerstone in the diagnosis and management of CMV infection in the immunocompromised host. We evaluated two automated and reproducible PCR tests, the LightCycler (Roche Molecular Biochemicals, Indianapolis, Ind.) and the COBAS AMPLICOR CMV Monitor (Roche Diagnostics, Pleasanton, Calif.), for the detection of CMV DNA in blood samples from transplant recipients with CMV infection as determined by shell vial culture. Following a log transformation analysis, the mean CMV DNA in plasma (PL), whole blood (WB), peripheral blood leukocytes (PBL), and peripheral blood mononuclear cells (PBMC) using the LightCycler was 6.79 copies per ml, 7.23 copies per ml, 6.38 copies per 2 × 10
6
cells, and 6.27 copies per 2 × 10
6
cells, respectively. This compares to 7.86 copies per ml, 8.37 copies per ml, 7.59 copies per 2 × 10
6
cells, and 7.44 copies per 2 × 10
6
cells, respectively, using COBAS AMPLICOR CMV Monitor. While higher CMV DNA levels were observed for the various blood compartments analyzed using COBAS AMPLICOR CMV Monitor, a high degree of correlation was evident between the two automated systems (jackknife correlation
r
= PL 0.77 [95% confidence interval (CI); 0.64, 0.90], WB 0.77 [95% CI; 0.62, 0.92], PBL 0.77 [95% CI; 0.67, 0.88], and PBMC 0.81 [95% CI; 0.72, 0.89], all
P
< 0.001). Therefore, we conclude that either automated diagnostic system is accurate for CMV DNA quantitation.
Molecular Variability of the Adhesin-Encoding Gene
pvpA
among
Mycoplasma gallisepticum
Strains and Its Application in Diagnosis
Authors: Liu T. , Garcı́a M. , Levisohn S. , Yogev D. , Kleven S. H.
Published: July 2002

Mycoplasma gallisepticum
is an important pathogen of chickens and turkeys that causes considerable economic losses to the poultry industry worldwide. The reemergence of
M. gallisepticum
outbreaks among poultry, the increased use of live
M. gallisepticum
vaccines, and the detection of
M. gallisepticum
in game and free-flying song birds has strengthened the need for molecular diagnostic and strain differentiation tests. Molecular techniques, including restriction fragment length polymorphism of genomic DNA (RFLP) and PCR-based random amplification of polymorphic DNA (RAPD), have already been utilized as powerful tools to detect intraspecies variation. However, certain intrinsic drawbacks constrain the application of these methods. The main goal of this study was to determine the feasibility of using an
M.
gallisepticum
-specific gene encoding a phase-variable putative adhesin protein (PvpA) as the target for molecular typing. This was accomplished using a
pvpA
PCR-RFLP assay. Size variations among PCR products and nucleotide divergence of the C-terminus-encoding region of the
pvpA
gene were the basis for strain differentiation. This method can be used for rapid differentiation of vaccine strains from field isolates by amplification directly from clinical samples without the need for isolation by culture. Moreover, molecular epidemiology of
M. gallisepticum
outbreaks can be performed using RFLP and/or sequence analysis of the
pvpA
gene.
Antimicrobial Surveillance of
Haemophilus influenzae
in the United States during 2000-2001 Leads to Detection of Clonal Dissemination of a β-Lactamase-Negative and Ampicillin-Resistant Strain
Authors: Karlowsky James A. , Critchley Ian A. , Blosser-Middleton Renée S. , Karginova Elena A. , Jones Mark E. , Thornsberry Clyde , Sahm Daniel F.
Published: July 2002

A 2000-2001 U.S.
Haemophilus influenzae
surveillance study (
n
= 1,434) detected nine (0.6%) β-lactamase-negative and ampicillin-resistant (BLNAR) isolates collected from two different hospitals. The MICs of ampicillin for all nine isolates were 4 μg/ml, with results being reproducible; and all nine isolates were susceptible to amoxicillin-clavulanate, cefuroxime, cefprozil, macrolides, and fluoroquinolones. Pulsed-field gel electrophoresis of genomic DNA following
Sma
I digestion demonstrated identical patterns for each of the nine isolates, suggesting intra- and interhospital dissemination of a BLNAR clone.
Simian Immunodeficiency Virus (SIV)gagDNA-Vaccinated Rhesus Monkeys Develop Secondary Cytotoxic T-Lymphocyte Responses and Control Viral Replication after Pathogenic SIV Infection
Authors: Egan Michael A. , Charini William A. , Kuroda Marcelo J. , Schmitz Jörn E. , Racz Paul , Tenner-Racz Klara , Manson Kelledy , Wyand Michael , Lifton Michelle A. , Nickerson Christie E. , Fu Tongming , Shiver John W. , Letvin Norman L.
Published: July 2002

The potential contribution of a plasmid DNA construct to vaccine-elicited protective immunity was explored in the simian immunodeficiency virus (SIV)/macaque model of AIDS. Making use of soluble major histocompatibility class I/peptide tetramers and peptide-specific killing assays to monitor CD8+T-lymphocyte responses to a dominant SIV Gag epitope in genetically selected rhesus monkeys, a codon-optimized SIVgagDNA vaccine construct was shown to elicit a high-frequency SIV-specific cytotoxic T-lymphocyte (CTL) response. This CTL response was demonstrable in both peripheral blood and lymph node lymphocytes. Following an intravenous challenge with the highly pathogenic viral isolate SIVsm E660, these vaccinated monkeys developed a secondary CTL response that arose with more rapid kinetics and reached a higher frequency than did the postchallenge CTL response in control plasmid-vaccinated monkeys. While peak plasma SIV RNA levels were comparable in the experimentally and control-vaccinated monkeys during the period of primary infection, thegagplasmid DNA-vaccinated monkeys demonstrated better containment of viral replication by 50 days following SIV challenge. These findings indicate that a plasmid DNA vaccine can elicit SIV-specific CTL responses in rhesus monkeys, and this vaccine-elicited immunity can facilitate the generation of secondary CTL responses and control of viral replication following a pathogenic SIV challenge. These observations suggest that plasmid DNA may prove a useful component of a human immunodeficiency virus type 1 vaccine.
Functional Characterization of the Human Immunodeficiency Virus Type 1 Genome by Genetic Footprinting
Authors: Laurent Louise Chang , Olsen Mari N. , Crowley Rachel Adams , Savilahti Harri , Brown Patrick O.
Published: July 2002

We present a detailed and quantitative analysis of the functional characteristics of the 1,000-nucleotide segment at the 5′ end of the human immunodeficiency virus type 1 (HIV-1) RNA genome. This segment of the viral genome contains several important
cis
-acting sequences, including the TAR, polyadenylation, viral
att
site, minus-strand primer-binding site, and 5′ splice donor sequences, as well as coding sequences for the matrix protein and the N-terminal half of the capsid protein. The genetic footprinting technique was used to determine quantitatively the abilities of 134 independent insertion mutations to (i) make stable viral RNA, (ii) assemble and release viral RNA-containing viral particles, and (iii) enter host cells, complete reverse transcription, enter the nuclei of host cells, and generate proviruses in the host genome by integration. All of the mutants were constructed and analyzed en masse, greatly decreasing the labor typically involved in mutagenesis studies. The results confirmed the presence of several previously known functional features in this region of the HIV genome and provided evidence for several novel features, including newly identified
cis
-acting sequences that appeared to contribute to (i) the formation of stable viral transcripts, (ii) viral RNA packaging, and (iii) an early step in viral replication. The results also pointed to an unanticipated
trans
-acting role for the N-terminal portion of matrix in the formation of stable viral RNA transcripts. Finally, in contrast to previous reports, the results of this study suggested that detrimental mutations in the matrix and capsid proteins principally interfered with viral assembly.
Tyrosine Phosphorylation of Bovine Herpesvirus 1 Tegument Protein VP22 Correlates with the Incorporation of VP22 into Virions
Authors: Ren Xiaodi , Harms Jerome S. , Splitter Gary A.
Published: July 2002

Tyrosine phosphorylation has been shown to play a role in the replication of several herpesviruses. In this report, we demonstrate that bovine herpesvirus 1 infection triggered tyrosine phosphorylation of proteins with molecular masses similar to those of phosphorylated viral structural proteins. One of the tyrosine-phosphorylated viral structural proteins was the tegument protein VP22. A tyrosine 38-to-phenylalanine mutation totally abolished the phosphorylation of VP22 in transfected cells. However, construction of a VP22 tyrosine 38-to-phenylalanine mutant virus demonstrated that VP22 was still phosphorylated but that the phosphorylation site may change to the C terminus rather than be in the N terminus as in wild-type VP22. In addition, the loss of VP22 tyrosine phosphorylation correlated with reduced incorporation of VP22 compared to that of envelope glycoprotein D in the mutant viruses but not with the amount of VP22 produced during virus infection. Our data suggest that tyrosine phosphorylation of VP22 plays a role in virion assembly.
Mutations within the Putative Membrane-Spanning Domain of the Simian Immunodeficiency Virus Transmembrane Glycoprotein Define the Minimal Requirements for Fusion, Incorporation, and Infectivity
Authors: West John T. , Johnston Patrick B. , Dubay Susan R. , Hunter Eric
Published: July 2002

The membrane-spanning domain (MSD) of a number of retroviral transmembrane (TM) glycoproteins, including those from the human and simian immunodeficiency viruses (HIV and SIV), have been predicted to contain a charged arginine residue. The wild-type SIV TM glycoprotein is 354 amino acids long. The entire putative cytoplasmic domain of SIV (amino acids 193 to 354) is dispensable for virus replication in vitro, and such truncation-containing viruses are capable of reaching wild-type titers after a short delay. We show here that further truncation of eight additional amino acids to TM185 results in a protein that lacks fusogenicity but is, nevertheless, efficiently incorporated into budding virions. By analyzing a series of nonsense mutations between amino acids 193 and 185 in Env expression vectors and in the SIVmac239 proviral clone, a region of the SIV TM that contains the minimum requirement for glycoprotein-mediated cell-to-cell fusion and that for virus replication was identified. Virus entry and infectivity were evident in truncations to a minimum of 189 amino acids, whereas cell-cell fusion was observed for a protein of only 187 amino acids. Glycoprotein was efficiently incorporated into budding virions in truncations up to 185 amino acids, indicating that such proteins are membrane anchored and are transported to the cell surface. However, truncation of the TM to 180 amino acids resulted in a protein that displays a transport defect and may be retained in the endoplasmic reticulum. Based on our analyses of these mutants, an alternative model for the MSD of SIV is proposed. Our model suggests that membrane-imbedded charged residues can be neutralized by side-chain interactions with lipid polar head groups. As a consequence, the membrane-spanning region can be reduced by more than a helical turn. This new model accounts for the ability of truncations within the predicted MSD to remain membrane anchored and maintain biological activity.
Release of Virus from Lymphoid Tissue Affects Human Immunodeficiency Virus Type 1 and Hepatitis C Virus Kinetics in the Blood
Authors: Müller Viktor , Marée Athanasius F. M. , De Boer Rob J.
Published: July 2002

Kinetic parameters of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) infections have been estimated from plasma virus levels following perturbation of the chronically infected (quasi-) steady state. We extend previous models by also considering the large pool of virus localized in the lymphoid tissue (LT) compartment. The results indicate that the fastest time scale of HIV-1 plasma load decay during therapy probably reflects the clearance rate of LT virus and not, as previously supposed, the clearance rate of virus in plasma. This resolves the discrepancy between the clearance rate estimates during therapy and those based on plasma apheresis experiments. In the extended models plasma apheresis measurements are indeed expected to reflect the plasma decay rate. We can reconcile all current HIV-1 estimates with this model when, on average, the clearance rate of virus in plasma is approximately 20 day
−1
, that of LT virus is approximately 3 day
−1
, and the death rate of virus-producing cells is approximately 0.5 day
−1
. The fast clearance in the LT compartment increases current estimates for total daily virus production. Because HCV is produced in the liver, we let virus be produced into the blood compartment of our model. The results suggest that extending current HCV models with an LT compartment is not likely to affect current estimates for kinetic parameters and virus production. Estimates for treatment efficacy might be affected, however.
Separation of Human Immunodeficiency Virus Type 1 Replication fromnef-Mediated Pathogenesis in the Human Thymus
Authors: Duus Karen M. , Miller Eric D. , Smith Jonathan A. , Kovalev Grigoriy I. , Su Lishan
Published: July 2002

Human immunodeficiency virus type 1 (HIV-1) is frequently attenuated after long-term culture in vitro. The attenuation process probably involves mutations of functions required for replication and pathogenicity in vivo. Analysis of attenuated HIV-1 for replication and pathogenicity in vivo will help to define these functions. In this study, we examined the pathogenicity of an attenuated HIV-1 isolate in a laboratory worker accidentally exposed to a laboratory-adapted HIV-1 isolate. Using heterochimeric SCID-hu Thy/Liv mice as an in vivo model, we previously defined HIV-1envdeterminants (HXB/LW) that reverted to replicate in vivo (L. Su, H. Kaneshima, M. L. Bonyhadi, R. Lee, J. Auten, A. Wolf, B. Du, L. Rabin, B. H. Hahn, E. Terwilliger, and J. M. McCune, Virology 227:46–52, 1997). Here we further demonstrate that HIV-1 replication in vivo can be separated from its pathogenic activity, in that the HXB/LW virus replicated to high levels in SCID-hu Thy/Liv mice, with no significant thymocyte depletion. Restoration of thenefgene in the recombinant HXB/LW genome restored its pathogenic activity, with no significant effect on HIV-1 replication in the thymus. Our results suggest that in vitro-attenuated HIV-1 lacks determinants for pathogenicity as well as for replication in vivo. Our data indicate that (i) the replication defect can be recovered in vivo by mutations in theenvgene, without an associated pathogenic phenotype, and (ii)nefcan function in the HXB/LW clone as a pathogenic factor that does not enhance HIV-1 replication in the thymus. Furthermore, the HXB/LW virus may be used to study mechanisms of HIV-1nef-mediated pathogenesis in vivo.
Application of Capillary GC/MS to the Analysis of Wastes from Chemical Plants. II. Identification of Naphthyl[b]thiophenes and Binaphthyls in Gaseous Releases from the Production of 2-Naphthol
Authors: Čermák Jiří , Sebránek Miloslav , Kulhánek Jiří
Published: July 2002

Naphthyl[b]thiophenes were identified in gaseous releases from the production of 2-naphthol based on the elucidation of their mass spectra. The identification was verified by comparison with mass spectra and retention data of the authentic compounds which were synthesized for this purpose. Three isomeric binaphthyls were also found in the industrial releases.
The Gas-Solid-Phase 2,5-Dioxopiperazine Synthesis. Cyclization of Vaporous Dipeptides on Silica Surface
Authors: Basiuk Vladimir A. , Gromovoy Taras Yu.
Published: July 2002

The "gas solid-phase" method is used for the preparation of both symmetric and asymmetric 2,5-dioxopiperazines via cyclization of vaporous linear dipeptides in the presence of silica.
Identification of 1-(3,4-Dihydroxyphenylazo)-2-hydroxynaphthalene as the Product of Oxidation of 1-Phenylazo-2-hydroxynaphthalene (Sudan I, Solvent Yellow 14) by Rat Liver Microsomes
Authors: Stiborová Marie , Asfaw Befekadu , Frei Eva , Schmeiser Heinz H. , Wiessler Manfred
Published: July 2002

The carcinogenic azo dye 1-phenylazo-2-hydroxynaphthalene (Sudan I, Solvent Yellow 14) is oxidized by rat liver microsomes to a number of azo-containing metabolites. One of the products of hitherto unknown structure has been shown to be identical with 1-(3,4-dihydroxyphenylazo)-2-hydroxynaphthalene. The identification of this product completed the pattern of major products of Sudan I oxidation by microsomal cytochrome P-450.
Polyfunctional Derivatives of Imidodiphosphoric Acid as Extractants
Authors: Navrátil Oldřich , Sládek Petr , Tokárová Alena , Herrmann Eckhard , Nouaman Moein
Published: July 2002

The distribution of calcium, strontium, barium and scandium between aqueous and organic phases was studied using 0.1 M HNO3 or 0.01 to 0.1 M HCl as the aqueous phase and solutions of selected derivatives of organophosphoric reagents containing the conventional =P(O)NHP(O)= bifunctional group or the analogous trifunctional or tetrafunctional group in various organic solvents as the organic phase. The effect of substitution of one ester group by an OH or NH2 group was examined. While for the alkaline earth metals the distribution ratio increases if the bifunctional group is replaced by a higher-functional group, the reverse is true for scandium. The extraction efficiency is improved by the presence of OH or NH2 substituent groups. The composition of the extracted species was inferred by logarithmic analysis and the corresponding extraction constants were calculated.
Heat Capacities of Some Alkyl Acetates at 295-323 K
Authors: Svoboda Václav , Gottmanová Kornelia , Hynek Vladimír , Koutek Bohumír
Published: July 2002

Molar heat capacities Cp,m at constant atmospheric pressure have been determined with a typical uncertainty of about 0.3% for eight liquid alkyl acetates H(CH2)nOCOCH3 (n = 6-12, 14), over the temperature range 295-323 K. The Cp,m values were found to be a linear function of temperature. A comparison of experimental data with those predicted by the group additivity method demonstrated a rather limited capability of the additivity scheme to predict correctly the Cp,m values for higher (n > 10) homologues in the series.
Sterically Crowded Heterocycles. XIII. An Insight Into the Absolute Stereochemistry of Atropisomeric (Z)-3-(Imidazo[1,2-a]pyridin-3-yl)prop-2-en-1-ones
Authors: Pohl Radek , Sýkora Jan , Maloň Petr , Böhm Stanislav , Kratochvíl Bohumil , Kuthan Josef
Published: July 2002

The absolute configuration of the atropisomeric (Z)-3-(5-methyl-2-phenylimidazo[1,2-a]pyridin-3-yl)-1,3-diphenylprop-2-en-1-one was evaluated to beRfor the dextrorotatory andSfor the laevorotatory enantiomers. The assignment is based on their two-step synthesesviaatropodiastereoisomeric carbamates prepared from the corresponding atropodiastereoisomeric alcohols with (R)-(+)-α-phenylethyl isocyanate and by a complete X-ray space analysis of the quaternary triiodide obtained from the (R)-(+)-enantiomer. CD spectra and PM3 calculated heats of formation for selected compounds are discussed in relation to the found molecular configurations.
Parameters of the Bender Equation of State for Chloro Derivatives of Methane and Chlorobenzene
Authors: Cibulka Ivan , Hnědkovský Lubomír , Růžička Květoslav
Published: July 2002

Values of adjustable parameters of the Bender equation of state evaluated for chloromethane, dichloromethane, trichloromethane, tetrachloromethane, and chlorobenzene from published experimental data are presented. Experimental data employed in the evaluation included the data on state behaviour (p-ρ-T) of fluid phases, vapour-liquid equilibrium data (saturated vapour pressures and orthobaric densities), second virial coefficients, and the coordinates of the gas-liquid critical point. The description of second virial coefficient by the equation of state is examined.
Effects of Oil Viscosity and Interfacial Reaction on the Displacement of Oil from Porous Media
Authors: Hornof Vladimir , Neale Graham H. , Yu Alex
Published: July 2002

Displacement of oil from unconsolidated porous media was investigated. Waterflooding and alkaline flooding tests were conducted in model porous media consisting of fine glass beads wet-packed into a cylindrical holder. Mixtures of light and heavy paraffin oil of viscosity ranging from 20 to 70 mPa s were used as the oil phase. Acidic oil was simulated by dissolving 10 mmol/l of linoleic acid in the oil. As expected, recovery of neutral oil by waterflooding decreased as oil viscosity increased. Addition of acid to the oil reduced the waterflooding recovery by more than 20% for all oils. Alkaline flooding of after-waterflood residual oil produced incremental recovery only in the case of the least viscous oil (20 mPa s). The incremental recovery increased with the concentration of alkali only up to 25 mmol/l and remained constant thereafter.
Infrared Study of Nitric Oxide (NO) Adsorption and Conversion on CeO2-ZrO2 Mixed Oxide
Authors: Fornasiero Paolo , Kašpar Jan
Published: July 2002

An IR study of adsorption of NO- and CO-containing mixtures on a high-surface-area Rh/Ce0.5Zr0.5O2 mixed oxide is reported. At low temperatures, NO strongly interacts with surface oxygen. The presence of various NOx-containing species co-ordinated both to cerium and zirconium has been observed. The NOx storage capacity is mainly associated with the presence of zirconium sites. The extension of NOx storage strongly depends on the adsorption temperature, which is associated with the presence/absence of reactive surface oxygen species. Formation of N2O22- as adsorbed species appears to be a possible key step in the mechanism for conversion of NO at low temperature.
Neurochemistry of L-Glutamate Transport in the CNS: A Review of Thirty Years of Progress
Authors: Balcar Vladimir J. , Takamoto Akiko , Yoneda Yukio
Published: July 2002

The review highlights the landmark studies leading from the discovery and initial characterization of the Na+-dependent "high affinity" uptake in the mammalian brain to the cloning of individual transporters and the subsequent expansion of the field into the realm of molecular biology. When the data and hypotheses from 1970's are confronted with the recent developments in the field, we can conclude that the suggestions made nearly thirty years ago were essentially correct: the uptake, mediated by an active transport into neurons and glial cells, serves to control the extracellular concentrations of L-glutamate and prevents the neurotoxicity. The modern techniques of molecular biology may have provided additional data on the nature and location of the transporters but the classical neurochemical approach, using structural analogues of glutamate designed as specific inhibitors or substrates for glutamate transport, has been crucial for the investigations of particular roles that glutamate transport might play in health and disease. Analysis of recent structure/activity data presented in this review has yielded a novel insight into the pharmacological characteristics of L-glutamate transport, suggesting existence of additional heterogeneity in the system, beyond that so far discovered by molecular genetics. More compounds that specifically interact with individual glutamate transporters are urgently needed for more detailed investigations of neurochemical characteristics of glutamatergic transport and its integration into the glutamatergic synapses in the central nervous system. A review with 162 references.
The First Synthesis of Geranyllinalool Enantiomers
Authors: Svatoš Aleš , Urbanová Klára , Valterová Irena
Published: July 2002

(3R)-(-)-Geranyllinalool and its (3S)-(+)-isomer were synthesized in 7 steps starting from both enantiomers of citramalic acid and geranyl bromide. The synthetic sequence established the absolute configurations of naturally occurring geranyllinalools for the first time.