bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental determination and calculations of redox potential descriptors of compounds directed against retroviral zinc fingers: Implications for rational drug design
Authors: Topol Igor A. , McGrath Connor , Chertova Elena , Dasenbrock Catherine , Lacourse William R. , Eissenstat Michael A. , Burt Stanley K. , Henderson Louis E. , Casas‐Finet José R. 
Published: July 2002

AbstractA diverse set of electrophilic compounds that react with cysteine thiolates in retroviral nucleocapsid (NC) proteins and abolish virus infectivity has been identified. Although different in chemical composition, these compounds are all oxidizing agents that lead to the ejection of Zn(II) ions bound to conserved structural motifs (zinc fingers) present in retroviral NC proteins. The reactivity of a congeneric series of aromatic disulfides toward the NC protein of the human immunodeficiency virus type 1 (HIV‐1), NCp7, has been characterized by HPLC separation of starting reagents from reaction products. We calculated the absolute redox potentials of these compounds in the gas phase and in aqueous solvent, using a density functional theory method and a continuum solvation model. Pulsed polarography experiments were performed and showed a direct correlation between calculated and experimentally determined redox propensities. A dependence between protein reactivity and redox potential for a specific compound was shown: Reaction with NCp7 did not take place below a threshold value of redox potential. This relationship permits the distinction between active and nonactive compounds targeted against NCp7, and provides a theoretical basis for a scale of reactivity with retroviral zinc fingers. Our results indicate that electrophilic agents with adequate thiophilicity to react with retroviral NC fingers can now be designed using known or calculated electrochemical properties. This may assist in the design of antiretroviral compounds with greater specificity for NC protein. Such electrophilic agents can be used in retrovirus inactivation with the intent of preparing a whole‐killed virus vaccine formulation that exhibits unaffected surface antigenic properties.
Microscopic Velocimetry With a Scaled-Up Model for Evaluating a Flow Field Over Cultured Endothelial Cells
Authors: Fukushima Shuichiro , Deguchi Takaaki , Kaibara Makoto , Oka Kotaro , Tanishita Kazuo 
Published: July 2002

AbstractA microscopic velocimetry technique for evaluating the flow field over cultured endothelial cells was developed. Flow around a cell model scaled up by a factor of 100 was visualized by using an optical microscope and was quantified by using particle-tracking velocimetry. Wall shear stress on the model surface was determined from a two-dimensional velocity field interpolated from measured velocity vectors. Accuracy of the velocimetry was verified by measuring the flow over a sinusoidal cell model that had a wall shear stress profile analytically determined with linear perturbation theory. Comparison of the experimental results with the analytical solution revealed that the total error of the measured wall shear stress was 6 percent.
Antimicrobial Resistance of
Neisseria gonorrhoeae
and Emerging Ciprofloxacin Resistance in The Netherlands, 1991 to 1998
Authors: de Neeling Albert J. , van Santen-Verheuvel Marga , Spaargaren Joke , Willems Rob J. L. 
Published: July 2002

ABSTRACT

Surveillance of antibiotic resistance in
Neisseria gonorrhoeae
showed a decrease in the percentage of β-lactamase-producing isolates but an increase in intermediately penicillin-resistant strains and strains resistant to a high level of tetracycline. MICs for the ciprofloxacin-resistant isolates that emerged increased, and these isolates had mutations in
gyrA
and
parC
similar to those observed in the Far East.
Levofloxacin Pharmacokinetics and Serum Bactericidal Activities against Five Enterobacterial Species
Authors: Geerdes-Fenge Hilte F. , Wiedersich Axel , Wagner S. , Lehr Karl-Heinz , Koeppe Peter , Lode Hartmut 
Published: July 2002

ABSTRACT

After oral administration of 500 mg of levofloxacin to 12 volunteers, we investigated the pharmacokinetics and serum bactericidal activities (SBAs) against five strains of members of the family
Enterobacteriaceae
. Pharmacokinetic data were as follows: maximum concentration in serum, 6.36 ± 0.57 mg/liter; area under the concentration-time curve, 43.6 ± 6.23 mg · h/liter; elimination half-life 4.23 ± 0.87 h. SBAs were present for 24 h against
Escherichia coli
and
Citrobacter freundii
. The SBAs at 1, 12, and 24 h after administration against
E. coli
were 1:108, 1:29, and 1:7, respectively, and those against
Citrobacter freundii
were 1:74, 1:25, and 1:7, respectively. The SBAs were present for 12 h against the other three organisms tested. The SBAs against
Serratia marcescens
were 1:28 and 1:9 at 1 and 12 h, respectively; the SBAs against
Klebsiella pneumoniae
were 1:25 and 1:7 at 1 and 12 h, respectively; and the SBAs against
Enterobacter cloacae
were 1:24 and 1:10 at 1 and 12 h, respectively.
MICs of Oxazolidinones for
Rhodococcus equi
Strains Isolated from Humans and Animals
Authors: Bowersock Terry L. , Salmon Sarah A. , Portis Ellen S. , Prescott John F. , Robison Denise A. , Ford Charles W. , Watts Jeffrey L. 
Published: July 2002

ABSTRACT

Eperezolid and linezolid are representatives of a new class of orally active, synthetic antimicrobial agents. The in vitro activity values (MICs) of linezolid, eperezolid, and comparator antibiotics against 102 strains of
Rhodococcus equi
isolated from humans and animals were determined. Linezolid was more active than eperezolid against the strains tested; premafloxacin was the most active comparator antibiotic.
In Vitro Activities of LY333328 and Comparative Agents against Nosocomial Gram-Positive Pathogens Collected in a 1997 Global Surveillance Study
Authors: Zeckel Michael L. , Preston David A. , Allen Bradley S. 
Published: July 2002

ABSTRACT

The in vitro activity of LY333328 was evaluated for 1,479 nosocomial gram-positive pathogens isolated in 12 countries during 1997. LY333328 MICs at which 90% of the isolates tested were inhibited for
Enterococcus faecalis
(
n
= 351),
Enterococcus faecium
(
n
= 100),
Staphylococcus aureus
(
n
= 593), coagulase-negative
Staphylococcus
species (
n
= 325), and
Streptococcus pneumoniae
(
n
= 110) were 1, 1, 2, 2, and 0.015 μg/ml, respectively. LY333328 demonstrated potent activity against isolates of vancomycin-resistant enterococci, oxacillin-resistant staphylococci, and penicillin-resistant pneumococci.
Blocking the Receptor for Interleukin 10 Protects Mice from Lethal Listeriosis
Authors: Silva Regina A. , Appelberg Rui 
Published: July 2002

ABSTRACTHigh doses ofListeria monocytogenesovercome the ability of a normal mouse to control the infection, due to massive bacterial replication. Treatment with an anti-interleukin 10 (IL-10) receptor monoclonal antibody prevented the fatal course of infection with high doses of bacteria. This work shows that blocking the receptor for IL-10 may have useful therapeutic applications.
Prevention and Treatment of Lethal Murine Endotoxemia by the Novel Immunomodulatory Agent MFP-14
Authors: Nicoletti Ferdinando , Di Marco Roberto , Sacerdote Paola , Meroni PierLuigi , Mangano Katia , Edwards Carl , Bartorelli Alberto , Bendtzen Klaus , Panerai Alberto 
Published: July 2002

ABSTRACTMultifunctional protein 14 (MFP-14) is a ubiquitous protein that inhibits the production of tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ), which are involved in the pathogenesis of sepsis. Here, lipopolysaccharide (LPS)-induced lethality in mice was markedly reduced by MFP-14. The treatment also lowered LPS-induced levels of TNF-α and IFN-γ in the blood.
Population Pharmacokinetics of Intramuscular Quinine in Children with Severe Malaria
Authors: Krishna Sanjeev , Nagaraja Nelamangala V. , Planche Tim , Agbenyega Tsiri , Bedo-Addo George , Ansong Daniel , Owusu-Ofori Alex , Shroads Albert L. , Henderson George , Hutson Alan , Derendorf Hartmut , Stacpoole Peter W. 
Published: July 2002

ABSTRACT

We present the first population pharmacokinetic analysis of quinine in patients with
Plasmodium falciparum
malaria. Ghanaian children (
n
= 120; aged 12 months to 10 years) with severe malaria received an intramuscular loading dose of quinine dihydrochloride (20 mg/kg of body weight). A two-compartment model with first-order absorption and elimination gave post hoc estimates for pharmacokinetic parameters that were consistent with those derived from non-population pharmacokinetic studies (clearance [CL] = 0.05 liter/h/kg of body weight; volume of distribution in the central compartment [
V
1
] = 0.65 liter/kg; volume of distribution at steady state = 1.41 liter/kg; half-life at β phase = 19.9 h). There were no covariates (including age, gender, acidemia, anemia, coma, parasitemia, or anticonvulsant use) that explained interpatient variability in weight-normalized CL and
V
1
. Intramuscular quinine was associated with minor, local toxicity in some patients (13 of 108; 12%), and 11 patients (10%) experienced one or more episodes of postadmission hypoglycemia. A loading dose of intramuscular quinine results in predictable population pharmacokinetic profiles in children with severe malaria and may be preferred to the intravenous route of administration in some circumstances.
Antibacterial Properties of Gemifloxacin and Trovafloxacin in Urine Ex Vivo: Phase I Study
Authors: Garcı́a-Calvo Gloria , Parra Araceli , Aguilar Lorenzo , Ponte Carmen , Giménez Marı́a J. , Carcas Antonio , Kinzig-Schippers Martina , Soriano Francisco 
Published: July 2002

ABSTRACT

Urine bactericidal titers (UBTs) against
Escherichia coli
ATCC 25922 and
Staphylococcus saprophyticus
ATCC 1970 were determined after the administration of single oral doses of gemifloxacin at 320 mg and trovafloxacin at 200 mg to healthy volunteers. Gemifloxacin presented significantly lower experimental versus mathematically predicted UBTs over 72 h, due to the effect of urine on the susceptibility of the
E. coli
strain. Experimental UBTs were significantly higher for gemifloxacin than trovafloxacin against both strains over 72 h.
Kinetic Study of Two Novel Enantiomeric Tricyclic β-Lactams Which Efficiently Inactivate Class C β-Lactamases
Authors: Vilar Mateja , Galleni Moreno , Solmajer Tom , Turk Boris , Frère Jean-Marie , Matagne André 
Published: July 2002

ABSTRACTA detailed kinetic study of the interaction between two ethylidene derivatives of tricyclic carbapenems, Lek 156 and Lek 157, and representative β-lactamases andd-alanyl–d-alanine peptidases (dd-peptidases) is presented. Both compounds are very efficient inactivators of theEnterobacter cloacae908R β-lactamase, which is usually resistant to inhibition. Preliminary experiments indicate that various extended-spectrum class C β-lactamases (ACT-1, CMY-1, and MIR-1) are also inactivated. With theE. cloacae908R enzyme, complete inactivation occurs with a second-order rate constant,k2/K′, of 2 × 104to 4 × 104M−1s−1, and reactivation is very slow, with a half-life of >1 h. Accordingly, Lek 157 significantly decreases the MIC of ampicillin forE. cloacaeP99, a constitutive class C β-lactamase overproducer. With the other serine β-lactamases tested, the covalent adducts exhibit a wide range of stabilities, with half-lives ranging from long (>4 h with the TEM-1 class A enzyme), to medium (10 to 20 min with the OXA-10 class D enzyme), to short (0.2 to 0.4 s with the NmcA class A β-lactamase). By contrast, both carbapenems behave as good substrates of theBacillus cereusmetallo-β-lactamase (class B). TheStreptomycessp. strain R61 and K15 extracellulardd-peptidases exhibit low levels of sensitivity to both compounds.
In Vitro Activity of Telithromycin against Spanish
Streptococcus pneumoniae
Isolates with Characterized Macrolide Resistance Mechanisms
Authors: Morosini Marı́a-Isabel , Cantón Rafael , Loza Elena , Negri Marı́a-Cristina , Galán Juan-Carlos , Almaraz Felisa , Baquero Fernando 
Published: July 2002

ABSTRACT

The susceptibilities to telithromycin of 203
Streptococcus pneumoniae
isolates prospectively collected during 1999 and 2000 from 14 different geographical areas in Spain were tested and compared with those to erythromycin A, clindamycin, quinupristin-dalfopristin, penicillin G, cefotaxime, and levofloxacin. Telithromycin was active against 98.9% of isolates (MICs, ≤0.5 μg/ml), with MICs at which 90% of isolates are inhibited being 0.06 μg/ml, irrespective of the resistance genotype. The corresponding values for erythromycin were 61.0% (MICs, ≤0.25 μg/ml) and >64 μg/ml. The
erm
(B) gene (macrolide-lincosamide-streptogramin B resistance phenotype) was detected in 36.4% (
n
= 74) of the isolates, which corresponded to 93.6% of erythromycin-intermediate and -resistant isolates, whereas the
mef
(A) gene (M phenotype [resistance to erythromycin and susceptibility to clindamycin and spiramycin without blunting]) was present in only 2.4% (
n
= 5) of the isolates. One of the latter isolates also carried
erm
(B). Interestingly, in one isolate for which the erythromycin MIC was 2 μg/ml, none of these resistance genes could be detected. Erythromycin MICs for
S. pneumoniae erm
(B)-positive isolates were higher (range, 0.5 to >64 μg/ml) than those for
erm
(B)- and
mef
(A)-negative isolates (range, 0.008 to 2 μg/ml). The corresponding values for telithromycin were lower for both groups, with ranges of 0.004 to 1 and 0.002 to 0.06 μg/ml, respectively. The erythromycin MIC was high for a large number of
erm
(B)-positive isolates, but the telithromycin MIC was low for these isolates. These results indicate the potential usefulness of telithromycin for the treatment of infections caused by erythromycin-susceptible and -resistant
S. pneumoniae
isolates when macrolides are indicated.
Microcin E492 Is an Unmodified Peptide Related in Structure to Colicin V
Authors: Pons Anne-Marie , Zorn Nathalie , Vignon David , Delalande François , Van Dorsselaer Alain , Cottenceau Gilles 
Published: July 2002

ABSTRACT
The pore-forming microcin E492 was purified by solid-phase extraction and reversed-phase high-pressure liquid chromatography. Its molecular mass was 7,886 Da. The entire 84-amino-acid sequence was determined. There is no postranslational modification in the secreted microcin, and the sequence has homologies with the sequence of the microcin colicin V.
Quantification of
Clostridium botulinum
Toxin Gene Expression by Competitive Reverse Transcription-PCR
Authors: McGrath S. , Dooley J. S. G. , Haylock R. W. 
Published: July 2002

ABSTRACT

Clostridium botulinum
produces a characteristic botulinum neurotoxin which can cause an often fatal neuroparalytic condition known as botulism. Although food-borne botulism is rare, critical screening by food companies is necessary to ensure that food products are safe. At present, the food industry assesses the risks of botulinum neurotoxin production by challenge testing to check any new food products and to check the efficacy of new storage regimes. Challenge testing involves artificial introduction of defined strains of microorganisms into food, and microbial growth and possible toxin production are then monitored. Botulinum toxin is normally analyzed by using the mouse bioassay. However, the mouse bioassay is expensive, slow, and politically sensitive because of animal rights issues. In this paper we describe adaptation of a new assay, competitive reverse transcription-PCR (RT-PCR), to monitor botulinum neurotoxin production. This method accurately measures the level of toxin-encoding mRNA in
C. botulinum
cells. Measurement of mRNA should provide a good indication of gene expression as mRNA is turned over rapidly in bacterial cells. In addition, the method is rapid, specific, and sensitive. The competitive RT-PCR method was developed to examine
C. botulinum
E VH toxin gene expression and was used to investigate the level of toxin production by
C. botulinum
E VH when the organism was grown in two different types of broth. The results which we obtained with the competitive RT-PCR method demonstrated that this method is more rapid and more sensitive than the mouse bioassay.
Molecular Cloning, Sequencing, and Expression in
Escherichia coli
of the Gene Encoding a Novel 5-Oxoprolinase without ATP-Hydrolyzing Activity from
Alcaligenes faecalis
N-38A
Authors: Nishimura Atsuhisa , Oyama Hiroshi , Hamada Takatoshi , Nobuoka Katsunori , Shin Takashi , Murao Sawao , Oda Kohei 
Published: July 2002

ABSTRACT

The gene encoding a novel 5-oxoprolinase without ATP-hydrolyzing activity from
Alcaligenes faecalis
N-38A was cloned and characterized. The coding region of this gene is 1,299 bp long. The predicted primary protein is composed of 433 amino acid residues, with a 31-amino-acid signal peptide. The mature protein is composed of 402 amino acid residues with a molecular mass of 46,163 Da. The derived amino acid sequence of the enzyme showed no significant sequence similarity to any other proteins reported so far. The 5-oxoprolinase gene was expressed in
Escherichia coli
by using a regulatory expression system with an isopropyl-β-
d
-thiogalactopyranoside-inducible
tac
promoter, and its expression level was approximately 16 mg per liter. The purified enzyme has the same characteristics as the authentic enzyme, except for the amino terminus, which has three additional amino acids. The enzyme was markedly inhibited by
p
-chloromercuribenzoic acid, EDTA,
o
-phenanthroline, HgCl
2
, and CuSO
4
. The EDTA-inactivated enzyme was completely restored by the addition of Zn
2+
or Co
2+
. In addition, the enzyme was found to contain 1 g-atom of zinc per mol of protein. These results suggest that the 5-oxoprolinase produced by
A. faecalis
N-38A is a zinc metalloenzyme.
Effects of pH and Energy Supply on Activity and Amount of Pyruvate Formate-Lyase in
Streptococcus bovis
Authors: Asanuma Narito , Hino Tsuneo 
Published: July 2002

ABSTRACT

The enzyme system of pyruvate formate-lyase (PFL) in
Streptococcus bovis
was investigated by isolating PFL and PFL-activating enzyme (PFL-AE) from
S. bovis
, flavodoxin from
Escherichia coli
, and chloroplasts from spinach. In this study, the PFL and PFL-AE in
S. bovis
were found to be similar to those in
E. coli
, suggesting that the activating mechanisms are similar. The optimal pH of
S. bovis
PFL was 7.5, which is in contrast to the optimal pH of
S. bovis
lactate dehydrogenase, which is 5.5. The apparent

K
m

of
S. bovis
PFL was 2 mM. The intermediates of glycolysis, dihydroxyacetone phosphate (DHAP) and
d
-glyceraldehyde-3-phosphate (GAP), were shown to inhibit PFL activity. The concentrations of intracellular DHAP and GAP in
S. bovis
ranged from 1.9 mM to less than 0.1 mM and from 0.6 mM to less than 0.05 mM, respectively, depending on the energy supply. The wide variations in DHAP and GAP levels indicated that PFL activity is allosterically regulated by these triose phosphates in vivo. The amount of PFL protein, as determined by Western blot analysis with polyclonal antibody, changed in parallel with the level of
pfl
-mRNA, responding to the culture conditions. These observations confirm that PFL synthesis is regulated at the transcriptional level and support the hypothesis that
S. bovis
shifts the fermentation pathway from acetate, formate, and ethanol production to lactate production when the pH is low and when excess energy is supplied.
β-Glutamate as a Substrate for Glutamine Synthetase
Authors: Robinson Patrice , Neelon Kelly , Schreier Harold J. , Roberts Mary F. 
Published: July 2002

ABSTRACT

The conversion of β-glutamate to β-glutamine by archaeal and bacterial glutamine synthetase (GS) enzymes has been examined. The GS from
Methanohalophilus portucalensis
(which was partially purified) is capable of catalyzing the amidation of this substrate with a rate sevenfold less than the rate obtained with α-glutamate. Recombinant GS from the archaea
Methanococcus jannaschii
and
Archaeoglobus fulgidus
were considerably more selective for α-glutamate than β-glutamate as a substrate. All the archaeal enzymes were much less selective than the two bacterial GS (from
Escherichia coli
and
Bacillus subtilis
), whose specific activities towards β-glutamate were much smaller than rates with the α-isomer. These results are discussed in light of the observation that β-glutamate is accumulated as an osmolyte in many archaea while β-glutamine (produced by glutamine synthetase) is used as an osmolyte only in
M. portucalensis
.
Construction of a Xylanase-Producing Strain of
Brevibacterium
lactofermentum
by Stable Integration of an Engineered
xysA
Gene from
Streptomyces
halstedii
JM8
Authors: Adham Sirin A. I. , Campelo Ana B. , Ramos Angelina , Gil José A. 
Published: July 2002

ABSTRACT

A xylanolytic strain of
Brevibacterium
lactofermentum
containing the
Streptomyces
halstedii
His-tagged
xysA
gene was generated. The new strain contains DNA derived from
S
.
halstedii
, expresses xylanolytic activity, and was obtained by an integrative process mediated by a conjugative plasmid targeted to a dispensable chromosomal region located downstream from the essential cell division gene
ftsZ
. The His-tagged Xys1 enzyme was constitutively expressed under the control of the
kan
promoter from Tn
5
and was easily purified by use of Ni-nitrilotriacetic acid-agarose. The new strain is stable for more than 200 generations, lacks any known antibiotic resistance gene, and does not need any selective pressure to maintain the integrated gene. This strategy can be used to integrate any gene into the
B
.
lactofermentum
chromosome and to maintain it stably without the use of antibiotics for selection.
Aerobic Biodegradation of Methyl
tert
-Butyl Ether by Aquifer Bacteria from Leaking Underground Storage Tank Sites
Authors: Kane S. R. , Beller H. R. , Legler T. C. , Koester C. J. , Pinkart H. C. , Halden R. U. , Happel A. M. 
Published: July 2002

ABSTRACT

The potential for aerobic methyl
tert
-butyl ether (MTBE) degradation was investigated with microcosms containing aquifer sediment and groundwater from four MTBE-contaminated sites characterized by oxygen-limited in situ conditions. MTBE depletion was observed for sediments from two sites (e.g., 4.5 mg/liter degraded in 15 days after a 4-day lag period), whereas no consumption of MTBE was observed for sediments from the other sites after 75 days. For sediments in which MTBE was consumed, 43 to 54% of added [U-
14
C]MTBE was mineralized to
14
CO
2
. Molecular phylogenetic analyses of these sediments indicated the enrichment of species closely related to a known MTBE-degrading bacterium, strain PM1. At only one site, the presence of water-soluble gasoline components significantly inhibited MTBE degradation and led to a more pronounced accumulation of the metabolite
tert
-butyl alcohol. Overall, these results suggest that the effects of oxygen and water-soluble gasoline components on in situ MTBE degradation will vary from site to site and that phylogenetic analysis may be a promising predictor of MTBE biodegradation potential.