bluuebunny/crossref_metadata_2025_split huggingface dataset:
Faropenem Transport across the Renal Epithelial Luminal Membrane via Inorganic Phosphate Transporter Npt1
Authors: Uchino Hiroshi , Tamai Ikumi , Yabuuchi Hikaru , China Kayoko , Miyamoto Ken-ichi , Takeda Eiji , Tsuji Akira 
Published: July 2002

ABSTRACT

We previously showed that the mouse inorganic phosphate transporter Npt1 operates in the hepatic sinusoidal membrane transport of anionic drugs such as benzylpenicillin and mevalonic acid. In the present study, the mechanism of renal secretion of penem antibiotics was examined by using a
Xenopus
oocyte expression system. Faropenem (an oral penem antibiotic) was transported via Npt1 with a Michaelis-Menten constant of 0.77 ± 0.34 mM in a sodium-independent but chloride ion-sensitive manner. When the concentration of chloride ions was increased, the transport activity of faropenem by Npt1 was decreased. Since the concentration gradient of chloride ions is in the lumen-to-intracellular direction, faropenem is expected to be transported from inside proximal tubular cells to the lumen. So, we tested the release of faropenem from
Xenopus
oocytes. The rate of efflux of faropenem from Npt1-expressing oocytes was about 9.5 times faster than that from control water-injected
Xenopus
oocytes. Faropenem transport by Npt1 was significantly inhibited by β-lactam antibiotics such as benzylpenicillin, ampicillin, cephalexin, and cefazolin to 24.9, 40.5, 54.4, and 26.2% of that for the control, respectively. Zwitterionic β-lactam antibiotics showed lesser inhibitory effects on faropenem uptake than anionic derivatives, indicating that Npt1 preferentially transports anionic compounds. Other anionic compounds, such as indomethacin and furosemide, and the anion transport inhibitor 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid significantly inhibited faropenem uptake mediated by Npt1. In conclusion, our results suggest that Npt1 participates in the renal secretion of penem antibiotics.
Pharmacodynamic Assessment of Cefprozil against
Streptococcus pneumoniae
: Implications for Breakpoint Determinations
Authors: Nicolau David P. , Onyeji Cyprian O. , Zhong Mingkang , Tessier Pamela R. , Banevicius Mary Anne , Nightingale Charles H. 
Published: July 2002

ABSTRACT

Cefprozil, an oral semisynthetic cephalosporin, is commonly utilized in the treatment of respiratory-tract infections in children. While this agent has provided acceptable clinical success over a number of years, this study was undertaken to better define its pharmacodynamic profile against
Streptococcus pneumoniae
. Nineteen clinical isolates of
S. pneumoniae
were utilized in the neutropenic murine thigh infection model. To simulate the pharmacokinetic profile of cefprozil in children, the renal function of mice was impaired with uranyl nitrate, and a commercially available cefprozil suspension (6 mg/kg of body weight) was administered orally every 12 h. Mice were infected with 10
6
to 10
7
CFU per thigh, and therapy was initiated 2 h later. At 0 and 24 h postinfection, thighs were harvested to determine bacterial density. Survival was assessed during 96 h of therapy. The magnitude of bacterial kill ranged from 0.5 to 4.4 log
10
CFU per thigh over 24 h, and the extent of microbial eradication was dependent on the MIC. Killing of more than 2.6 log
10
CFU per thigh was observed with MICs of ≤3 μg/ml, while either minimal killing or growth was detected with MICs of ≥4 μg/ml. Mortality in untreated control animals was 100%. Animals infected with strains for which the MICs were ≤2 μg/ml survived the infection, whereas MICs exceeding 2 μg/ml resulted in substantial mortality. These studies demonstrate the effectiveness of cefprozil against isolates of the pneumococcus for which the MICs are ≤2 μg/ml using a drug exposure typically observed in children. These data support a susceptibility breakpoint of ≤2 μg/ml for cefprozil.
Antileishmanial Activities of Stearylamine-Bearing Liposomes
Authors: Dey Tuhina , Anam Khairul , Afrin Farhat , Ali Nahid 
Published: July 2002

ABSTRACT

Here we report the activity of liposomes comprising egg phosphatidylcholine (PC) and stearylamine (SA) against
Leishmania donovani
parasites. Both promastigotes and intracellular amastigotes in vitro and in vivo were susceptible to SA-PC liposomes. A single dose of 55 mg of SA-PC liposomes/animal could significantly reduce the hepatic parasite burden by 85 and 68% against recent and established experimental visceral leishmaniasis, respectively, suggesting their strong therapeutic potential.
High-Affinity Binding of Silybin Derivatives to the Nucleotide-Binding Domain of a
Leishmania tropica
P-Glycoprotein-Like Transporter and Chemosensitization of a Multidrug-Resistant Parasite to Daunomycin
Authors: Pérez-Victoria José M. , Pérez-Victoria F. Javier , Conseil Gwenaëlle , Maitrejean Mathias , Comte Gilles , Barron Denis , Di Pietro Attilio , Castanys Santiago , Gamarro Francisco 
Published: July 2002

ABSTRACT

In order to overcome the multidrug resistance mediated by P-glycoprotein-like transporters in
Leishmania
spp., we have studied the effects produced by derivatives of the flavanolignan silybin and related compounds lacking the monolignol unit on (i) the affinity of binding to a recombinant C-terminal nucleotide-binding domain of the
L. tropica
P-glycoprotein-like transporter and (ii) the sensitization to daunomycin on promastigote forms of a multidrug-resistant
L. tropica
line overexpressing the transporter. Oxidation of the flavanonol silybin to the corresponding flavonol dehydrosilybin, the presence of the monolignol unit, and the addition of a hydrophobic substituent such as dimethylallyl, especially at position 8 of ring A, considerably increased the binding affinity. The in vitro binding affinity of these compounds for the recombinant cytosolic domain correlated with their modulation of drug resistance phenotype. In particular, 8-(3,3-dimethylallyl)-dehydrosilybin effectively sensitized multidrug-resistant
Leishmania
spp. to daunomycin. The cytosolic domains are therefore attractive targets for the rational design of inhibitors against P-glycoprotein-like transporters.
Antipneumococcal Activity of Ertapenem (MK-0826) Compared to Those of Other Agents
Authors: Pankuch Glenn A. , Davies Todd A. , Jacobs Michael R. , Appelbaum Peter C. 
Published: July 2002

ABSTRACT

The activities of ertapenem (MK-0826) and eight other agents against a range of penicillin-susceptible and -resistant pneumococci were tested by determination of MICs by the microdilution method and by the time-kill methodology. For 125 penicillin-susceptible, 74 penicillin-intermediate, and 86 penicillin-resistant pneumococci, the MICs at which 50% of isolates are inhibited (MIC
50
s) and MIC
90
s, as determined by the microdilution method, were as follows: for ertapenem, 0.016 and 0.03, 0.125 and 0.5, and 0.5 and 1.0 μg/ml for penicillin-susceptible, penicillin-intermediate, and penicillin-resistant pneumococci, respectively; for amoxicillin, ≤0.016 and 0.03, 0.25 and 1.0, and 2.0 and 2.0 μg/ml for penicillin-susceptible, penicillin-intermediate, and penicillin-resistant pneumococci, respectively; for cefprozil, 0.125 and 0.25, 1.0 and 8.0, and 16.0 and 16.0 μg/ml for penicillin-susceptible, penicillin-intermediate, and penicillin-resistant pneumococci, respectively; for cefepime, ≤0.016 and 0.06, 0.5 and 1.0, and 1.0 and 2.0 μg/ml for penicillin-susceptible, penicillin-intermediate, and penicillin-resistant pneumococci, respectively; for ceftriaxone, ≤0.016 and 0.06, 0.25 and 1.0, and 1.0 and 2.0 μg/ml for penicillin-susceptible, penicillin-intermediate, and penicillin-resistant pneumococci, respectively; for imipenem, ≤0.008 and ≤0.008, 0.03 and 0.25, and 0.25 and 0.25 μg/ml for penicillin-susceptible, penicillin-intermediate, and penicillin-resistant pneumococci, respectively; for meropenem, ≤0.008 and 0.016, 0.125 and 0.5, and 0.5 and 1.0 μg/ml for penicillin-susceptible, penicillin-intermediate, and penicillin-resistant pneumococci, respectively; and for clarithromycin, 1.0 and >32.0, 1.0 and >32.0, and >32.0 and >32.0 μg/ml for penicillin-susceptible, penicillin-intermediate, and penicillin-resistant pneumococci, respectively. For 64 strains for which quinolone MICs were increased (ciprofloxacin MICs, ≥4.0 μg/ml), the MIC
90
of ertapenem was 1.0 μg/ml and the MIC
90
s of the other β-lactams tested and clarithromycin were >32.0 μg/ml. Against four penicillin-susceptible, four penicillin-intermediate, and four penicillin-resistant strains, testing by the time-kill methodology showed that ertapenem at two times the MIC was bacteriostatic (99% killing) after 12 h and bactericidal (99.9% killing) against all strains by 24 h, with 90% killing of all strains at two times the MIC after 6 h. At the MIC, ertapenem was bacteriostatic against all strains tested after 24 h. Although the bactericidal activity of imipenem at the MIC after 24 h was significantly greater than that of ertapenem, the kinetics of the two drugs at two times the MIC were similar after 24 h. The killing kinetics of clarithromycin were slower than those of ertapenem and other agents, with clarithromycin at two times the MIC having bactericidal activity against seven of eight macrolide-susceptible strains after 24 h.
Lack of Interaction of Fluoroquinolones with Lipopolysaccharides
Authors: Lindner B. , Wiese A. , Brandenburg K. , Seydel U. , Dalhoff A. 
Published: July 2002

ABSTRACT

Fluoroquinolones are known to chelate with di- and trivalent cations, and it has accordingly been claimed that they perturb the integrity of the outer membrane (OM) of gram-negative bacteria. So far, chelation has not been assessed in biologically relevant test systems. Therefore, we investigated the interaction of ciprofloxacin and moxifloxacin in the absence and presence of Mg
2+
with whole bacteria and isolated lipopolysaccharide (LPS) from various rough mutant strains of
Salmonella enterica
chemotypes by applying different biophysical techniques. We found that the fluoroquinolones did not disturb the integrity of the OM and neither were incorporated into LPS monolayers nor displaced Ca
2+
from LPS monolayers, suggesting that chelation of fluoroquinolones with divalent cations does not contribute to the antibacterial effect of fluoroquinolones.
Possible Interactions within a Methanotrophic-Heterotrophic Groundwater Community Able To Transform Linear Alkylbenzenesulfonates
Authors: Hršak Dubravka , Begonja Ana 
Published: July 2002

ABSTRACT
The relationships and interactions within a methanotrophic-heterotrophic groundwater community were studied in a closed system (shake culture) in the presence of methane as the primary carbon and energy source and with the addition of the pure linear alkylbenzenesulfonate (LAS) congener 2-[4-(sulfophenyl)]decan as a cometabolic substrate. When cultured under different conditions, this community was shown to be a stable association, consisting of one obligate type II methanotroph and four or five heterotrophs possessing different nutritional and physiological characteristics. The results of experiments examining growth kinetics and nutritional relationships suggested that a number of complex interactions existed in the community in which the methanotroph was the only member able to grow on methane and to cometabolically initiate LAS transformation. These growth and metabolic activities of the methanotroph ensured the supply of a carbon source and specific nutrients which sustained the growth of four or five heterotrophs. In addition to the obligatory nutritional relationships between the methanotroph and heterotrophs, other possible interactions resulted in the modification of basic growth parameters of individual populations and a concerted metabolic attack on the complex LAS molecule. Most of these relationships conferred beneficial effects on the interacting populations, making the community adaptable to various environmental conditions and more efficient in LAS transformation than any of the individual populations alone.
Detection and Identification of Decay Fungi in Spruce Wood by Restriction Fragment Length Polymorphism Analysis of Amplified Genes Encoding rRNA
Authors: Jasalavich Claudia A. , Ostrofsky Andrea , Jellison Jody 
Published: July 2002

ABSTRACT
We have developed a DNA-based assay to reliably detect brown rot and white rot fungi in wood at different stages of decay. DNA, isolated by a series of CTAB (cetyltrimethylammonium bromide) and organic extractions, was amplified by the PCR using published universal primers and basidiomycete-specific primers derived from ribosomal DNA sequences. We surveyed 14 species of wood-decaying basidiomycetes (brown-rot and white-rot fungi), as well as 25 species of wood-inhabiting ascomycetes (pathogens, endophytes, and saprophytes). DNA was isolated from pure cultures of these fungi and also from spruce wood blocks colonized by individual isolates of wood decay basidiomycetes or wood-inhabiting ascomycetes. The primer pair ITS1-F (specific for higher fungi) and ITS4 (universal primer) amplified the internal transcribed spacer region from both ascomycetes and basidiomycetes from both pure culture and wood, as expected. The primer pair ITS1-F (specific for higher fungi) and ITS4-B (specific for basidiomycetes) was shown to reliably detect the presence of wood decay basidiomycetes in both pure culture and wood; ascomycetes were not detected by this primer pair. We detected the presence of decay fungi in wood by PCR before measurable weight loss had occurred to the wood. Basidiomycetes were identified to the species level by restriction fragment length polymorphisms of the internal transcribed spacer region.
Screening of Genes Involved in Isooctane Tolerance in
Saccharomyces cerevisiae
by Using mRNA Differential Display
Authors: Miura Shigenori , Zou Wen , Ueda Mitsuyoshi , Tanaka Atsuo 
Published: July 2002

ABSTRACT

A
Saccharomyces cerevisiae
strain, KK-211, isolated by the long-term bioprocess of stereoselective reduction in isooctane, showed extremely high tolerance to the solvent, which is toxic to yeast cells, but, in comparison with its wild-type parent, DY-1, showed low tolerance to hydrophilic organic solvents, such as dimethyl sulfoxide and ethanol. In order to detect the isooctane tolerance-associated genes, mRNA differential display (DD) was employed using mRNAs isolated from strains DY-1 and KK-211 cultivated without isooctane, and from strain KK-211 cultivated with isooctane. Thirty genes were identified as being differentially expressed in these three types of cells and were classified into three groups according to their expression patterns. These patterns were further confirmed and quantified by Northern blot analysis. On the DD fingerprints, the expression of 14 genes, including
MUQ1
,
PRY2
,
HAC1
,
AGT1
,
GAC1
, and
ICT1
(
YLR099c
) was induced, while the expression of the remaining 16 genes, including
JEN1
,
PRY1
,
PRY3
, and
KRE1
, was decreased, in strain KK-211 cultivated with isooctane. The genes represented by
HAC1
,
PRY1
, and
ICT1
have been reported to be associated with cell stress, and
AGT1
and
GAC1
have been reported to be involved in the uptake of trehalose and the production of glycogen, respectively.
MUQ1
and
KRE1
, encoding proteins associated with cell surface maintenance, were also detected. Based on these results, we concluded that alteration of expression levels of multiple genes, not of a single gene, might be the critical determinant for isooctane tolerance in strain KK-211.
Suitability of PCR Fingerprinting, Infrequent-Restriction-Site PCR, and Pulsed-Field Gel Electrophoresis, Combined with Computerized Gel Analysis, in Library Typing of
Salmonella enterica
Serovar Enteritidis
Authors: Garaizar Javier , López-Molina Nuria , Laconcha Idoia , Lau Baggesen Dorte , Rementeria Aitor , Vivanco Ana , Audicana Ana , Perales Ildefonso 
Published: July 2002

ABSTRACT

Strains of
Salmonella enterica
(
n
= 212) of different serovars and phage types were used to establish a library typing computerized system for serovar Enteritidis on the basis of PCR fingerprinting, infrequent-restriction-site PCR (IRS-PCR), or pulsed-field gel electrophoresis (PFGE). The rate of PCR fingerprinting interassay and intercenter reproducibility was low and was only increased when DNA samples were extracted at the same time and amplified with the same reaction mixtures. Reproducibility of IRS-PCR technique reached 100%, but discrimination was low (
D
= 0.52). The PFGE procedure showed an intercenter reproducibility value of 93.3%. The high reproducibility of PFGE combined with the previously determined high discrimination directed its use for library typing. The use of PFGE with enzymes
Xba
I,
Bln
I, and
Spe
I for library typing of serovar Enteritidis was assessed with GelCompar 4.0 software. Three computer libraries of PFGE DNA profiles were constructed, and their ability to recognize new DNA profiles was analyzed. The results obtained pointed out that the combination of PFGE with computerized analysis could be suitable in long-term epidemiological comparison and surveillance of
Salmonella
serovar Enteritidis, specially if the prevalence of genetic events that could be responsible for changes in PFGE profiles in this serovar was low.
A Simple, Rapid Method for Demonstrating Bacterial Flagella
Authors: Grossart Hans-Peter , Steward Grieg F. , Martinez Josefina , Azam Farooq 
Published: July 2002

ABSTRACT
We developed a simple, rapid method for demonstrating flagellation of bacteria using the fluorescent protein stain NanoOrange (Molecular Probes, Eugene, Oreg.). The NanoOrange reagent binds to hydrophobic regions of proteins, which results in substantial enhancement of fluorescence. Unbound reagent is essentially nonfluorescent. NanoOrange fluorescently stained bacterial cell bodies, as well as flagella and other appendages, which could be directly observed by epifluorescence microscopy. Detection of flagella was further improved by using a charge-coupled device camera for image capture and processing. The reliability of the method was tested by using 37 pure cultures of marine bacteria. Detection of flagella on the isolates by NanoOrange staining was compared to detection by transmission electron microscopy (TEM). For 36 of 37 cultures, the two methods yielded the same results. In one case, flagella were detected by TEM but not by NanoOrange, although the difference may be attributable to differences between the culture preparations. NanoOrange staining is rapid (10 to 15 min) and does not require fixation or dehydration, so live samples can be stained. Since NanoOrange is a general protein stain and works directly in seawater, it may also prove to be useful for staining other proteinaceous material that is of interest to aquatic microbial ecologists.
An Activator of Transcription Regulates Phage TP901-1 Late Gene Expression
Authors: Brøndsted Lone , Pedersen Margit , Hammer Karin 
Published: July 2002

ABSTRACT

A promoter active in the late phase of the lytic cycle of lactococcal bacteriophage TP901-1 has been identified. The promoter is tightly regulated and requires the product of the phage TP901-1
orf29
for activity. A deletion analysis of the late promoter region showed that a fragment as small as 99 bp contains both the promoter and the region necessary for activation by ORF29. The transcriptional start site of the promoter was identified by primer extension to position 13073 on the TP901-1 genome, thus located 87 bp downstream of
orf29
in a 580-bp intergenic region between
orf29
and
orf30.
Furthermore, the region located −85 to −61 bp upstream of the start site was shown to be necessary for promoter activity. During infection, the transcript arising from the late promoter is fully induced at 40 min postinfection, and our results suggest that a certain level of ORF29 must be reached in order to activate transcription of the promoter. Several lactococcal bacteriophages encode ORF29 homologous proteins, indicating that late transcription may be controlled by a similar mechanism in these phages. With the identification of this novel regulator, our results suggest that within the P335 group of lactococcal phages at least two regulatory systems controlling transcription in the late stage of infection exist.
Diversity and Distribution in Hypersaline Microbial Mats of Bacteria Related to
Chloroflexus
spp
Authors: Nübel Ulrich , Bateson Mary M. , Madigan Michael T. , Kühl Michael , Ward David M. 
Published: July 2002

ABSTRACT

Filamentous bacteria containing bacteriochlorophylls
c
and
a
were enriched from hypersaline microbial mats. Based on phylogenetic analyses of 16S rRNA gene sequences, these organisms form a previously undescribed lineage distantly related to
Chloroflexus
spp. We developed and tested a set of PCR primers for the specific amplification of 16S rRNA genes from filamentous phototrophic bacteria within the kingdom of “green nonsulfur bacteria.” PCR products recovered from microbial mats in a saltern in Guerrero Negro, Mexico, were subjected to cloning or denaturing gradient gel electrophoresis and then sequenced. We found evidence of a high diversity of bacteria related to
Chloroflexus
which exhibit different distributions along a gradient of salinity from 5.5 to 16%.
Immunological Diagnosis of Human Hydatid Cyst Relapse: Utility of the Enzyme-Linked Immunoelectrotransfer Blot and Discriminant Analysis
Authors: Gadea I. , Ayala G. , Diago M. T. , Cuñat A. , Garcia de Lomas J. 
Published: July 2002

ABSTRACT

A discriminant technique was applied to the different serological patterns obtained by enzyme-linked immunoelectrotransfer blotting (EITB) and by conventional immunological tests, in order to differentiate the residual antibody patterns present in healed hydatidosis from the ones present in patients with active hydatidosis. For this purpose, specific antibodies against
Echinococcus granulosus
were detected by indirect hemagglutination, agglutination of latex particles, basophil degranulation, and EITB for 23 patients with active hydatidosis and 45 patients with surgically cured hydatidosis. Discriminant analysis of the different serological patterns obtained by EITB and conventional serology correctly classified 92.54% of patients (93.3% if the patients are differentiated according to the time elapsed since surgery). This method detected the presence of active hydatidosis in 95.6% of patients for whom abdominal ultrasonography had confirmed the presence of active hydatid cysts. The global specificity was 88.9%. The specificity was 97.1% for patients who had been operated on 3 years ago or more and 63.6% for patients with less time since surgery.