Abstract:
:Nucleobase and nucleoside transporters play central roles in the biochemistry of parasitic protozoa, as they lack the ability to synthesize purines de novo and are absolutely reliant upon purine salvage from their hosts. Furthermore, such transporters are potentially critical to the pharmacology of these important human pathogens, because they mediate the uptake of purine analogues, as well as some nonpurine drugs, that can be selectively cytotoxic to the parasites. We here report the first identification and characterization of a purine nucleobase transporter in Leishmania amastigotes. Uptake of [3H]hypoxanthine by Leishmania mexicana amastigotes was mediated by a single high-affinity transporter, LmexNBT1, with a Km of 1.6 +/- 0.4 microM and high affinity for adenine, guanine, and xanthine but low affinity for nucleosides and pyrimidine nucleobases. Allopurinol, an antileishmanial hypoxanthine analogue, was apparently taken up by the same transporter. Using [3H]allopurinol, a Km value of 33.6 +/- 6.0 microM was obtained. All evidence was compatible with a model of a single purine nucleobase transporter being expressed in amastigotes. Using various purine nucleobase analogues, a model for the interactions between hypoxanthine and the transporter's permeant binding site was constructed. The binding interactions were compared with those of the LmajNBT1 transporter in Leishmania major promastigotes and found to be very similar.
journal_name
Antimicrob Agents Chemotherjournal_title
Antimicrobial agents and chemotherapyauthors
Al-Salabi MI,de Koning HPdoi
10.1128/AAC.49.9.3682-3689.2005subject
Has Abstractpub_date
2005-09-01 00:00:00pages
3682-9issue
9eissn
0066-4804issn
1098-6596pii
49/9/3682journal_volume
49pub_type
杂志文章abstract::Antifungal effects of iron chelators (lactoferrin, deferoxamine, deferiprone, and ciclopirox) were tested alone and in combination with antifungal drugs against Aspergillus fumigatus B5233 conidia. Lactoferrin, ciclopirox, and deferiprone inhibited whereas deferoxamine enhanced fungal growth. Antifungal synergy agains...
journal_title:Antimicrobial agents and chemotherapy
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abstract::Pefloxacin has been shown to have good intraocular penetration when given systemically. In order to extend its clinical use, we have assessed the tolerability, kinetics, and efficacy of subconjunctival pefloxacin in phakic pigmented rabbits. The tolerability of a single subconjunctival injection of pefloxacin (0.8, 1....
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.39.4.834
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journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.36.10.2093
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abstract::To identify the polymyxin receptor molecules in the membranes of living microorganisms, fusion of intact Acholeplasma laidlawii B with lipid vesicles was investigated according to the procedure of Grant and McConnell (1973). The naturally polymyxin-resistant A. laidlawii B was treated with phospholipid vesicles prepar...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.9.1.26
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abstract::A portion of the Mycobacterium tuberculosis gene encoding the beta subunit of RNA polymerase (rpoB) was amplified by PCR using degenerate oligonucleotides and used as a hybridization probe to isolate plasmid clones carrying the entire rpoB gene of M. tuberculosis H37Rv, a virulent, rifampin-susceptible strain. Sequenc...
journal_title:Antimicrobial agents and chemotherapy
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更新日期:1994-04-01 00:00:00
abstract::Hypermutation is a common feature of Pseudomonas aeruginosa isolates from chronically infected cystic fibrosis patients that is linked with antibiotic resistance development. In this work, using a large collection of sequential P. aeruginosa isolates from ICU patients, we found that despite the fact that mutational an...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
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abstract::A number of proflavine (PF)-resistant mutants of Escherichia coli B were also resistant to penicillin and cephalothin. Mutants resistant to 1.0 mM PF were 10 times more penicillin resistant than were the PF-susceptible, wild-type cells. Single-step mutants selected for resistance to either PF or penicillin were also r...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.10.4.765
更新日期:1976-10-01 00:00:00
abstract::We investigated the impact of the piperacillin-tazobactam MIC in the outcome of 39 bloodstream infections due to extended-spectrum-β-lactamase-producing Escherichia coli. All 11 patients with urinary tract infections survived, irrespective of the MIC. For other sources, 30-day mortality was lower for isolates with a M...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.00135-13
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journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.30.1.196
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journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.25.5.630
更新日期:1984-05-01 00:00:00
abstract::We performed the characterization of a multidrug-resistant (MDR) Enterobacter spp. isolate highlighting the genetic aspects of the antimicrobial resistance genes. An Enterobacter spp. isolate (Ec61) was recovered in 2014 from a transtracheal aspirate sample from a patient admitted to a Brazilian tertiary hospital and ...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.01193-20
更新日期:2020-12-14 00:00:00
abstract::The continued evolution of bacterial resistance to the β-lactam class of antibiotics has necessitated countermeasures to ensure continued effectiveness in the treatment of infections caused by bacterial pathogens. One relatively successful approach has been the development of new β-lactam analogs with advantages over ...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.02240-19
更新日期:2020-07-22 00:00:00
abstract::Various fluoroquinolones (norfloxacin, enoxacin, ofloxacin, levofloxacin, and sparfloxacin) induce DnaK and GroEL heat shock proteins in Escherichia coli. The induction is transient, consistent with the kinetics of cellular DNA relaxation. The concentrations of fluoroquinolones required for induction are similar to th...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.41.1.193
更新日期:1997-01-01 00:00:00
abstract::Novel sulfonated derivatives of poly(allylamine hydrochloride) (NSPAHs) and N-sulfonated chitosan (NSCH) have been synthesized, and their activity against influenza A and B viruses has been studied and compared with that of a series of carrageenans, marine polysaccharides of well-documented anti-influenza activity. NS...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.02183-15
更新日期:2016-03-25 00:00:00
abstract::Biapenem, formerly LJC 10,627 or L-627, a carbapenem antibiotic, was studied in its interactions with 12 beta-lactamases belonging to the four molecular classes proposed by R. P. Ambler (Philos. Trans. R. Soc. Lond. Biol. Sci. 289:321-331, 1980). Kinetic parameters were determined. Biapenem was readily inactivated by ...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.39.6.1300
更新日期:1995-06-01 00:00:00
abstract::We identified the carbapenemase gene blaOXA-499, a variant of blaOXA-143, from a clinical isolate of Acinetobacter pittii for the first time. OXA-499 shared 93.1% amino acid identity with OXA-143, and the gene was located on the chromosome. By cloning the OXA-499-encoding gene into the pWH1266 vector and transforming ...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.02676-16
更新日期:2017-04-24 00:00:00
abstract::Nikkomycins are nucleoside-peptide antibiotics produced by Streptomyces species with antifungal activities through the inhibition of chitin synthesis. We investigated the antifungal activities of nikkomycin Z alone and in combination with fluconazole and itraconazole. Checkerboard synergy studies were carried out by a...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.43.6.1401
更新日期:1999-06-01 00:00:00
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journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.41.8.1677
更新日期:1997-08-01 00:00:00
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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更新日期:2020-12-16 00:00:00
abstract::Chagas disease is a parasitic infection that leads to a significant public health problem in countries where the disease is endemic and where it is nonendemic. Benznidazole is the most commonly used drug for the etiological treatment of Chagas disease. Patients treated with benznidazole suffer frequent adverse drug re...
journal_title:Antimicrobial agents and chemotherapy
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doi:10.1128/AAC.04078-14
更新日期:2015-01-01 00:00:00
abstract::Extensive biochemical testing and 16S rRNA and rpoB sequence analysis revealed that clinical strain CF01Ent1, initially identified as Buttiauxella agrestis by the use of Api 32 biochemical strips, is a new organism in the Enterobacteriaceae family. It produced an inducible AmpC-type beta-lactamase whose sequence share...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.46.10.3316-3319.2002
更新日期:2002-10-01 00:00:00
abstract::Among respiratory tract isolates of Streptococcus pneumoniae from children, resistance to penicillins, cephalosporins, macrolides, and trimethoprim-sulfamethoxazole (SXT) increases on an annual basis. Pediatric patients who do not respond to conventional therapy for respiratory tract infections someday may be treated ...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.47.6.1790-1797.2003
更新日期:2003-06-01 00:00:00
abstract::This study describes the population pharmacokinetics of fosfomycin in critically ill patients. In this observational study, serial blood samples were taken over several dosing intervals of intravenous fosfomycin treatment. Blood samples were analyzed using a validated liquid chromatography-tandem mass spectrometry tec...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章,多中心研究
doi:10.1128/AAC.01321-15
更新日期:2015-10-01 00:00:00
abstract::PER-2 was the first detected and the second most prevalent extended-spectrum beta-lactamase in clinical pathogens isolated in Argentina and was also reported only in other South American countries. Citrobacter freundii 33587 was isolated in 1999 in Buenos Aires and was resistant to all tested beta-lactams except cepha...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.01395-06
更新日期:2007-07-01 00:00:00
abstract::Hepatitis C virus (HCV) inhibitors include direct-acting antivirals (DAAs) such as NS3 serine protease inhibitors, nucleoside and nonnucleoside polymerase inhibitors, and host-targeting antivirals (HTAs) such as cyclophilin inhibitors that have been developed in recent years. Drug-resistant HCV variants have been repo...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.00294-11
更新日期:2011-09-01 00:00:00
abstract::Mutants with multiple low-level antibiotic resistance were isolated from virulent wild-type Aeromonas salmonicida strains exposed to a low concentration of any one of several low-molecular-mass (approximately 635 daltons or less) antibiotics. Multiple resistance was toward beta-lactam compounds (penicillin G, ampicill...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.29.6.992
更新日期:1986-06-01 00:00:00
abstract::An inhibitor-based characterization system which allowed the identification of beta-lactamases after isoelectric focusing on polyacrylamide gels was developed. This system, using potassium clavulanate and oxacillin, distinguished type I chromosomally mediated enzymes from other beta-lactamases of gram-negative bacteri...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.30.6.951
更新日期:1986-12-01 00:00:00
abstract::Although ampicillin has been suggested as a useful agent for the treatment of nocardiosis in man, little is known regarding the presence of beta-lactamase in Nocardia or its possible role in determining resistance to ampicillin and the other beta-lactam antibiotics. We have evaluated 55 isolates of Nocardia for suscep...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/aac.14.5.704
更新日期:1978-11-01 00:00:00
abstract::Stenotrophomonas maltophilia is an emerging nosocomial pathogen that displays high-level intrinsic resistance to a variety of structurally unrelated antimicrobial agents. Efflux mechanisms are known to contribute to acquired multidrug resistance in this organism, and indeed, one such multidrug efflux system, SmeDEF, w...
journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.45.12.3497-3503.2001
更新日期:2001-12-01 00:00:00