bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression, crystallization and preliminary X-ray analysis of the E2 transactivation domain from papillomavirus type 16
Authors: Burns Julie E. , Moroz Olga V. , Antson Alfred A. , Sanders Cyril M. , Wilson Keith S. , Maitland Norman J. 
Published: July 2002

The N-terminal transactivation domain of the E2 protein from human papillomavirus type 16 has been crystallized by vapour diffusion. Crystals belong to the space group P3121 (or P3221) with unit-cell dimensions a = b = 54.3, c = 155.5 Å. There is one molecule per asymmetric unit with a solvent content of 55%. Crystals diffract to at least 2.5 Å resolution and complete X-ray data to 3.4 Å have been collected on a conventional laboratory source. This 201- amino-acid domain of the E2 protein has been shown to interact functionally with both the HPV E1 protein and at least three cellular transcription factors, to fulfil its role in the control of viral transcription and replication. A knowledge of the structural basis of these multiple interactions should lead to a fuller understanding of the mechanism of action of this key regulator of the HPV life cycle.
Crystallization of L-aspartate oxidase, the first enzyme in the bacterial de novo biosynthesis of NAD
Authors: Bacchella Luca , Lina Claudio , Todone Flavia , Negri Armando , Tedeschi Gabriella , Ronchi Severino , Mattevi Andrea 
Published: July 2002

The flavoenzyme L-aspartate oxidase from Escherichia coli was crystallized using the hanging-drop vapour-diffusion technique with PEG 4000 as precipitant. The crystals belong to space group P3121 (or P3221) with unit-cell parameters a = b = 84.9, c = 159.9 Å. A solvent content of 42% corresponds to a monomer (60 kDa) in the asymmetric unit. A complete 2.8 Å resolution data set was collected using a rotating-anode X-ray generator.
Purification, crystallization and preliminary crystallographic analysis of a natural complex of phospholipase A2 from Echis carinatus (saw-scaled viper)
Authors: Nagpal Akanksha , Chandra Vikas , Kaur Punit , Singh T. P. 
Published: July 2002

A novel complex of phospholipase A2 complexed with another venom protein has been isolated and purified from saw-scaled viper (Echis carinatus) venom. The molecular weights of the two components are 16 and 14 kDa, respectively. The complex was purified using an Affigel blue column and an anion-exchange (DEAE Sephacel) column. Long diamond-shaped crystals were obtained by hanging-drop vapour diffusion. The protein complex was dissolved at a concentration of 10 mg ml−1 in 20 mM sodium cacodylate, 1 mM CaCl2 and 2% dioxane at pH 6.0. The reservoir contained the same buffer with 7%(w/v) PEG 4000. Crystals appeared within 2–3 weeks. Native data to 2.9 Å resolution have been obtained at 291 K. The crystals belong to the monoclinic space group P21 with unit-cell parameters a = 74.47, b = 47.87, c = 106.39 Å, β = 104.5° and contain two molecules per asymmetric unit. Structure determination by molecular replacement is in progress.
Crystallization and preliminary diffraction analysis of the HincII restriction endonuclease–DNA complex
Authors: Horton Nancy C. , Dorner Lydia F. , Schildkraut Ira , Perona John J. 
Published: July 2002

Crystals of the 60 kDa dimeric HincII restriction enzyme bound to a 12 base-pair dyad-symmetric duplex DNA carrying the specific 5′-GTCGAC recognition site have been obtained. Crystals grew by hanging-drop vapor diffusion from solutions containing polyethylene glycol 4000 as precipitating agent. The rod-shaped crystals belong to space group I222 (or I212121), with unit-cell dimensions a = 66.9, b = 176.7, c = 256.0 Å. There are most likely to be two dimeric complexes in the asymmetric unit. A complete native data set has been collected from a high-energy synchrotron source to a resolution of 2.5 Å at 100 K, with an R
merge of 4.8%.
An Intelligent Sensor
Validation and Fault Diagnostic Technique for Diesel Engines
Authors: Mesbahi Ehsan 
Published: July 2002

Abstract
An intelligent sensor validation and on-line fault diagnosis technique for a 6 cylinder turbocharged diesel engine is proposed and studied. A single auto-associative 3-layer Artificial Neural Network (ANN), is trained to examine the accuracy of the measured data and allocate a confidence level to each signal. The same ANN is used to recover the missing or faulty data with a close approximation. For on-line fault detection a feed-forward ANN is trained to classify and consequently recognize faulty and healthy behavior of the engine for a wide range of operating conditions. The proposed technique is also equipped with an on-line learning mechanism, which is activated when the confidence level in predicted fault is poor. It is hoped that a feasible, practical, and reliable sensor reading, as well as highly accurate fault diagnosis system, would be achieved.
Pressure and Suction Surfaces Redesign for High-Lift Low-Pressure
Turbines
Authors: González P. , Ulizar I. , Vázquez R. , Hodson H. P. 
Published: July 2002

Abstract
Nowadays there is a big effort toward improving the low-pressure turbine efficiency even to the extent of penalizing other relevant design parameters. LP turbine efficiency influences SFC more than other modules in the engine. Most of the research has been oriented to reduce profile losses, modifying the suction surface, the pressure surface, or the three-dimensional regions of the flow. To date, the pressure surface has received very little attention. The dependence of the profile losses on the behavior of both pressure and suction surfaces has been investigated for the case of a high-lift design that is representative of a modern civil engine LP turbine. The experimental work described in this paper consists of two different sets of experiments: the first one concluded an improved pressure surface definition, and the second set was oriented to achieve further improvement in losses modifying the profile suction surface. Three profiles were designed and tested over a range of conditions. The first profile is a thin-solid design. This profile has a large pressure side separation bubble extending from near the leading edge to midchord. The second profile is a hollow design with the same suction surface as the first one, but avoiding pressure surface separation. The third one is also a hollow design with the same pressure surface as the second profile, but more aft loaded suction surface. The study is part of a wider ongoing research program covering the effects of the different design parameters on losses. The paper describes the experiments conducted in a low-speed linear cascade facility. It gathers together steady and unsteady loss measurements by wake traverse and surface pressure distributions for all the profiles. It is shown that thick profiles generate only around 90 percent of the losses of a thin-solid profile with the same suction surface. The results support the idea of an optimum axial position for the peak Mach number. Caution is recommended, as profile aft loading would not be a completely secure method for reducing losses.
Bioavailability of Praziquantel Increases with Concomitant Administration of Food
Authors: Castro Nelly , Medina Roberto , Sotelo Julio , Jung Helgi 
Published: July 2002

ABSTRACT
In the present study we found that after a single oral dose of 1,800 mg of praziquantel, following a high-lipid diet and a high-carbohydrate diet, the maximum levels in plasma increased 243 and 515% and the area under the plasma concentration curve from 0 to 8 h increased 180 and 271%, respectively.
The Triple Combination Indinavir-Zidovudine-Lamivudine Is Highly Synergistic
Authors: Snyder Stuart , D'Argenio D. Z. , Weislow Owen , Bilello John A. , Drusano G. L. 
Published: July 2002

ABSTRACT

Administration of the combination of indinavir-zidovudine-lamivudine has been demonstrated to cause a large fraction of treated patients to have a decline in human immunodeficiency virus type 1 (HIV-1) copy number to below the detectability of sensitive assays. A recent investigation (G. L. Drusano, J. A. Bilello, D. S. Stein, M. Nessly, A. Meibohm, E. A. Emini, P. Deutsch, J. Condra, J. Chodakewitz, and D. J. Holder, J. Infect. Dis. 178:360–367, 1998) demonstrated that the durability of the antiviral effect was affected by combination chemotherapy. Zidovudine-lamivudine-indinavir differed significantly from the combination of zidovudine plus indinavir. We hypothesized that the addition of lamivudine might alter the regimen, producing a synergistic anti-HIV effect. In vitro analysis of drug interaction demonstrated that zidovudine-indinavir interacted additively. The addition of lamivudine in concentrations which suppressed viral replication by 20% or less by itself demonstrated marked increases in the synergy volume, increasing the synergy volume 20-fold with the addition of 320 nM lamivudine (which does not suppress HIV by itself) and 40-fold with the addition of 1,000 nM lamivudine (20% viral inhibition as a single agent). A fully parametric analysis with a newly developed model for three-drug interaction confirmed and extended these observations. The interaction term (α
IND,AZT,3TC
) for all three drugs showed the greatest degree of synergy. This marked synergistic interaction among the three agents may explain some of the clinical results which differentiate this regimen from the double-drug regimen of zidovudine plus indinavir.
Induction of Fibronectin-Binding Proteins and Increased Adhesion of Quinolone-ResistantStaphylococcus aureusby Subinhibitory Levels of Ciprofloxacin
Authors: Bisognano Carmelo , Vaudaux Pierre , Rohner Peter , Lew Daniel P. , Hooper David C. 
Published: July 2002

ABSTRACTWe recently reported that strain EN1252a, a fluoroquinolone-resistant derivative ofStaphylococcus aureusNCTC8325 with mutations ingrlAandgyrA, expressed increased levels of fibronectin-binding proteins (FnBPs) and showed a significantly higher attachment to fibronectin-coated polymer surfaces after growth in the presence of subinhibitory concentrations of ciprofloxacin. The present study evaluated the occurrence and frequency of fluoroquinolone-induced FnBP-mediated adhesion in clinical isolates of fluoroquinolone-resistant methicillin-resistantS. aureus(MRSA) and methicillin-susceptibleS. aureus(MSSA). Eight of ten MRSA isolates and four of six MSSA isolates withgrlAandgyrAmutations exhibited significant increases in attachment to fibronectin-coated surfaces after growth in the presence of one-quarter the MIC of ciprofloxacin. Fluoroquinolone-induced FnBP-mediated adhesion of one clinical MRSA strain and the double mutant strain EN1252a also occurred on coverslips removed from the subcutaneous space of guinea pigs. For strain EN1252a, the regulation offnbtranscription by sub-MICs of ciprofloxacin was studied on reporter plasmids carryingfnb-luxABfusions. One-quarter of the MIC of ciprofloxacin significantly increasedfnbB, but notfnbA, promoter activity of the fluoroquinolone-resistant mutant but not its fluoroquinolone-susceptible parent ISP794. This response was abolished by pretreatment with rifampin, indicating an effect at the level of transcription. Activation of thefnbBpromoter was not due to an indirect effect of ciprofloxacin on growth rate and still occurred in anagrmutant of strain EN1252a. These data suggest that sub-MIC levels of ciprofloxacin activate thefnbBpromoter of some laboratory and clinical isolates, thus contributing to increased production of FnBP(s) and leading to higher levels of bacterial attachment to fibronectin-coated or subcutaneously implanted coverslips.
Therapeutic Responses to Quinine and Clindamycin in Multidrug-Resistant Falciparum Malaria
Authors: Pukrittayakamee Sasithon , Chantra Arun , Vanijanonta Sirivan , Clemens Ralf , Looareesuwan Sornchai , White Nicholas J. 
Published: July 2002

ABSTRACT

Therapeutic responses to clindamycin in combination with quinine were assessed in adult Thai patients with uncomplicated multidrug-resistant
Plasmodium falciparum
malaria. In total 204 patients were randomized to receive a 7-day oral treatment regimen of quinine (Q
7
) either alone (
n
= 68), in combination with clindamycin (Q
7
C
7
;
n
= 68), or in combination with tetracycline (Q
7
T
7
;
n
= 68). All patients had uncomplicated recoveries with no serious adverse effects. Fever clearance times for both of the two combination regimens (median of 47 h and range of 8 to 120 h for Q
7
C
7
and median of 36 h and range of 8 to 117 h for Q
7
T
7
) were significantly shorter than that for the Q
7
-only regimen (median, 56; range, 4 to 152 h) (
P
= 0.002). Parasite clearance times (overall mean ± standard deviation, 78 ± 23 h) were not significantly different between the three treatment groups (
P
= 0.98). The cure rates assessed at 28 days of follow-up were 100% for Q
7
C
7
and 98% for Q
7
T
7
, whereas the cure rate was 87% for the Q
7
-only regimen (
P
≤ 0.04). Clindamycin in combination with quinine is a safe and effective treatment for multidrug-resistant
P. falciparum
malaria. This combination may be of particular value in children and pregnant women, in whom tetracyclines are contraindicated.
Activities of Imipenem and Cephalosporins against Clonally Related Strains of
Escherichia coli
Hyperproducing Chromosomal β-Lactamase and Showing Altered Porin Profiles
Authors: Martínez-Martínez L. , Conejo M. C. , Pascual A. , Hernández-Allés S. , Ballesta S. , Ramírez de Arellano-Ramos E. , Benedí V. J. , Perea E. J. 
Published: July 2002

ABSTRACT

Forty clonally related clinical isolates of
Escherichia coli
from hospitalized patients were resistant to cefoxitin (MICs, >256 μg/ml) and ceftazidime (MICs, 32 to 256 μg/ml) and were intermediate or resistant to cefotaxime (MICs, 16 to 128 μg/ml) but susceptible to both cefepime (MICs, 0.5 to 2 μg/ml) and imipenem (MICs, 0.125 to 0.25 μg/ml). Resistance to β-lactams was related to high-level production of AmpC β-lactamase and loss of OmpF porin.
Drug Susceptibility Testing of Anaerobic Protozoa
Authors: Upcroft Jacqueline A. , Upcroft Peter 
Published: July 2002

ABSTRACT

A simple technique for routine, reproducible global surveillance of the drug susceptibility status of the anaerobic protozoa
Trichomonas, Entamoeba
, and
Giardia
is described. Data collected using this technique can be readily compared among different laboratories and with previously reported data. The technique employs a commercially available sachet and bag system to generate a low-oxygen environment and log
2
drug dilutions in microtiter plates, which can be monitored without aerobic exposure, to assay drug-resistant laboratory lines and clinically resistant isolates. MICs (after 2 days) of 3.2 and 25 μM indicated metronidazole-sensitive and highly clinically resistant isolates of
T. vaginalis
in anaerobic assays, respectively. The aerobic MICs were 25 and >200 μM. MICs (1 day) of 12.5 to 25 μM were found for axenic lines of
E. histolytica
, and MICs for
G. duodenalis
(3 days) ranged from 6.3 μM for metronidazole-sensitive isolates to 50 μM for laboratory metronidazole-resistant lines. This technique should encourage more extensive monitoring of drug resistance in these organisms.
Susceptibilities of
Mycobacterium
marinum
to Gatifloxacin, Gemifloxacin, Levofloxacin, Linezolid, Moxifloxacin, Telithromycin, and Quinupristin-Dalfopristin (Synercid) Compared to Its Susceptibilities to Reference Macrolides and Quinolones
Authors: Bråbäck Martin , Riesbeck Kristian , Forsgren Arne 
Published: July 2002

ABSTRACT

The susceptibility pattern of
Mycobacterium
marinum
was determined. Quinupristin-dalfopristin and telithromycin were less active than clarithromycin. Linezolid showed good antimicrobial activity at clinically achievable concentrations. Gatifloxacin, levofloxacin, and moxifloxacin displayed activities similar to those of ciprofloxacin. Gemifloxacin was less active. The Etest method showed variable agreement with the reference method.
Site-Specific Recombination with the Chromosomal tRNA
Leu
Gene by the Large Conjugative
Haemophilus
Resistance Plasmid
Authors: Dimopoulou Ioanna D. , Russell Joanne E. , Mohd-Zain Zaini , Herbert Rebecca , Crook Derrick W. 
Published: July 2002

ABSTRACT

Characterization of the sequences involved in recombination of the
Haemophilus
plasmid p1056 with the
Haemophilus influenzae
chromosome produced evidence indicating site-specific recombination with chromosomal tRNA
Leu
.
attP
sequences identical to those of p1056 were found in six plasmids of diverse origin, suggesting that a family of
Haemophilus
plasmids recombines with chromosomal tRNA
Leu
.
Resistance Determinants and Clonal Diversity in Group A Streptococci Collected during a Period of Increasing Macrolide Resistance
Authors: Cresti Stefania , Lattanzi Maria , Zanchi Alessandra , Montagnani Francesca , Pollini Simona , Cellesi Carla , Rossolini Gian Maria 
Published: July 2002

ABSTRACT

Susceptibility to macrolides and lincosamides was investigated with 299 consecutive nonduplicate
Streptococcus pyogenes
clinical isolates collected over a 6-year period (1992 to 1997) from an area of central Italy. During this period, macrolide resistance rates steadily increased (from 9% in 1992 to 53% in 1997;
P
< 0.001). The increase was caused by isolates with a macrolide-lincosamide-streptogramin B resistance phenotype, carrying mostly
erm
(B) but also
erm
(TR) genes, that were not detected in the first 2 years and were detected with increasing prevalence (8, 5, 26, and 37%, respectively) during the following 4 years. During the same period, the prevalence of isolates with a macrolide resistance phenotype, carrying
mef
(A) determinants, did not vary significantly; on average it was 13%, with modest rate fluctuations in different years and no definite trend. Molecular typing revealed a remarkable clonal diversity among susceptible and resistant isolates and a notable heterogeneity of the genetic environment of the resistance genes. The analysis of clonal diversity in relation with resistance phenotypes and genotypes revealed that increased macrolide resistance rates were due to a complex interplay of different mechanisms, with a relevant contribution played by an “epidemic” spread of genetic elements carrying the
erm
(B) gene among the circulating streptococcal population.
Role of
rpoS
in Acid Resistance and Fecal Shedding of
Escherichia coli
O157:H7
Authors: Price Stuart B. , Cheng Chorng-Ming , Kaspar Charles W. , Wright James C. , DeGraves Fred J. , Penfound Thomas A. , Castanie-Cornet Marie-Pierre , Foster John W. 
Published: July 2002

ABSTRACT

Acid resistance (AR) is important to survival of
Escherichia coli
O157:H7 in acidic foods and may play a role during passage through the bovine host. In this study, we examined the role in AR of the
rpoS
-encoded global stress response regulator ς
S
and its effect on shedding of
E. coli
O157:H7 in mice and calves. When assayed for each of the three AR systems identified in
E. coli
, an
rpoS
mutant (
rpoS
::pRR10) of
E. coli
O157:H7 lacked the glucose-repressed system and possessed reduced levels of both the arginine- and glutamate-dependent AR systems. After administration of the
rpoS
mutant and the wild-type strain (ATCC 43895) to ICR mice at doses ranging from 10
1
to 10
4
CFU, we found the wild-type strain in feces of mice given lower doses (10
2
versus 10
3
CFU) and at a greater frequency (80% versus 13%) than the mutant strain. The reduction in passage of the
rpoS
mutant was due to decreased AR, as administration of the mutant in 0.05 M phosphate buffer facilitated passage and increased the frequency of recovery in feces from 27 to 67% at a dose of 10
4
CFU. Enumeration of
E. coli
O157:H7 in feces from calves inoculated with an equal mixture of the wild-type strain and the
rpoS
mutant demonstrated shedding of the mutant to be 10- to 100-fold lower than wild-type numbers. This difference in shedding between the wild-type strain and the
rpoS
mutant was statistically significant (
P
≤ 0.05). Thus, ς
S
appears to play a role in
E. coli
O157:H7 passage in mice and shedding from calves, possibly by inducing expression of the glucose-repressed RpoS-dependent AR determinant and thus increasing resistance to gastrointestinal stress. These findings may provide clues for future efforts aimed at reducing or eliminating this pathogen from cattle herds.
Effect of Temperature and Salinity Stress on Growth and Lipid Composition of
Shewanella gelidimarina
Authors: Nichols David S. , Olley June , Garda Horacio , Brenner Rodolfo R. , McMeekin Tom A. 
Published: July 2002

ABSTRACT

The maximum growth temperature, the optimal growth temperature, and the estimated normal physiological range for growth of
Shewanella gelidimarina
are functions of water activity (a
w
), which can be manipulated by changing the concentration of sodium chloride. The growth temperatures at the boundaries of the normal physiological range for growth were characterized by increased variability in fatty acid composition. Under hyper- and hypoosmotic stress conditions at an a
w
of 0.993 (1.0% [wt/vol] NaCl) and at an a
w
of 0.977 (4.0% [wt/vol] NaCl) the proportion of certain fatty acids (monounsaturated and branched-chain fatty acids) was highly regulated and was inversely related to the growth rate over the entire temperature range. The physical states of lipids extracted from samples grown at stressful a
w
values at the boundaries of the normal physiological range exhibited no abrupt gel-liquid phase transitions when the lipids were analyzed as liposomes. Lipid packing and adaptational fatty acid composition responses are clearly influenced by differences in the temperature-salinity regime, which are reflected in overall cell function characteristics, such as the growth rate and the normal physiological range for growth.
Motility of
Marichromatium gracile
in Response to Light, Oxygen, and Sulfide
Authors: Thar Roland , Kühl Michael 
Published: July 2002

ABSTRACT

The motility of the purple sulfur bacterium
Marichromatium gracile
was investigated under different light regimes in a gradient capillary setup with opposing oxygen and sulfide gradients. The gradients were quantified with microsensors, while the behavior of swimming cells was studied by video microscopy in combination with a computerized cell tracking system.
M. gracile
exhibited photokinesis, photophobic responses, and phobic responses toward oxygen and sulfide. The observed migration patterns could be explained solely by the various phobic responses. In the dark,
M. gracile
formed an ∼500-μm-thick band at the oxic-anoxic interface, with a sharp border toward the oxic zone always positioned at ∼10 μM O
2
. Flux calculations yielded a molar conversion ratio S
tot
/O
2
of 2.03:1 (S
tot
= [H
2
S] + [HS
−
] + [S
2−
]) for the sulfide oxidation within the band, indicating that in darkness the bacteria oxidized sulfide incompletely to sulfur stored in intracellular sulfur globules. In the light,
M. gracile
spread into the anoxic zone while still avoiding regions with >10 μM O
2
. The cells also preferred low sulfide concentrations if the oxygen was replaced by nitrogen. A light-dark transition experiment demonstrated a dynamic interaction between the chemical gradients and the cell's metabolism. In darkness and anoxia,
M. gracile
lost its motility after ca. 1 h. In contrast, at oxygen concentrations of >100 μM with no sulfide present the cells remained viable and motile for ca. 3 days both in light and darkness. Oxygen was respired also in the light, but respiration rates were lower than in the dark. Observed aggregation patterns are interpreted as effective protection strategies against high oxygen concentrations and might represent first stages of biofilm formation.