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At least 667 records · Page 37Linked to original sources
PubMed2006

A mannose-specific tetrameric lectin with mitogenic and antibacterial activities from the ovary of a teleost, the cobia (Rachycentron canadum).

A tetrameric lectin, with hemagglutinating activity toward rabbit erythrocytes and with specificity toward D-mannosamine and D(+)-mannose, was isolated from the ovaries of a teleost, the cobia Rachycentron canadum. The isolation protocol comprised ion exchange chromatography on CM-cellulose and Q-Sepharose, ion exchange chromatography by fast protein liquid chromatography (FPLC) on Mono Q, and finally gel filtration by FPLC on Superose 12. The lectin was adsorbed on all ion exchangers used. It exhibited a molecular mass of 180 kDa in gel filtration on Superose 12 and a single 45-kDa band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that it is a tetrameric protein. The hemagglutinating activity of the lectin was stable up to 40 degrees C and between pH 4 and pH 10. All hemagglutinating activity disappeared at 60 degrees C and at pH 1 and pH 13. The hemagglutinating activity was doubled in the presence of 0.1 microM FeCl3. The lectin exerted antibacterial activity against Escherichia coli with 50% inhibition at 250 microg. There was no antifungal activity toward Coprinus comatus, Fusarium oxysporum, Mycosphaerella arachidicola, and Rhizoctonia solani at a dose of 300 microg. The lectin exhibited maximal mitogenic response from mouse splenocytes at a concentration of 14 microM.

Animals↗
PubMed2006

"All-in-one-plate" E-test and disk diffusion susceptibility co-testing for multiresistant Acinetobacter baumannii.

Multiresistant Acinetobacter baumannii requires ancillary manual susceptibility testing with the E-test and disk diffusion when tested with the VITEK-2 system (bioMérieux, Marcy l'Etoile, France). In the study presented here, the E-test and disk diffusion were combined in a single plate, and the method was verified by comparing categorical agreement of combined and control plates. There were no very major, major or minor errors, and similar results were obtained for all ten representative bacterial strains used as controls. Co-testing is thus feasible, accurate and reproducible, and it merits evaluation with other bacterial species.

Acinetobacter baumannii↗
PubMed1988

The use of a monoclonal antibody serotyping system in the study of the epidemiology of Pseudomonas aeruginosa.

A monoclonal antibody method was used as a primary O serotyping method for 1084 isolates of Pseudomonas aeruginosa, using commercially available antibody reagents in slide agglutination tests with whole-cell antigen. Differences in distribution of serogroups were found between various hospitals in the district. Serotyping provided useful information in the investigation of suspected incidents of cross-infection. Colonization at multiple sites, or over periods of time, in a single patient usually involved only a single serogroup.

Agglutination Tests↗
PubMed2006

In vitro anti-microbial and in vivo cytokine modulating effects of different prepared Chinese herbal medicines.

The toxicity, antimicrobial and cytokine modulating effects of herbal medicines in treating periodontal diseases were evaluated in this study. Using the broth dilution method and disc agar diffusion test, in individual and combined decocted preparations, different concentrations of Ching-Wei-San and its individual herbal components, Coptidis rhizoma, Angelicae sinensis radix, Rehmanniae radixet rhizom, Moutan radicis cortex, and Cimicifuga foetida, were tested for in vitro inhibitory effects on three well-known plaque-causing bacteria, Porphyromonas gingivialis, Streptococcus sanguis, and Streptococcus mutans, and two common pathogens, Staphylococcus aureus and Escherichia coli. The cytokine modulating effects were evaluated in Balb/c mice. The results suggested that one milliliter Ching-Wei-San at the 25,000 mg/mL concentration daily for the mice had significantly high levels in the liver function indexes in the 3-day acute toxicity test and in both the liver and kidney function indexes in the 28-day subacute toxicity test (P<0.01). The 250 mg/mL Ching-Wei-San is comparable to 250 mg/mL of tetracycline, and had similar inhibitory effects on the tested bacteria. Coptidis rhizoma (62.5 mg/mL) was the only individual herbal component to show 100% inhibitory effects. The mean cytokine ratios of IL-2, IL-4, IFN-gamma, and TNF-alpha in Balb/c mice treated with individual herbal components were shown to be different from each other. Ching-Wei-San modulated the immunity of mice, up-regulated IL-2, IL-4 and TNF-alpha, but down-regulated IFN-gamma. The effects of none of the individual herbal components alone can substitute for the cumulative effect of Ching-Wei-San.

Animals↗
PubMed2002

Antiretroviral activity and cytotoxicity of novel zidovudine (AZT) derivatives and the relation to their chemical structure.

Zidovudine (AZT) was the first nucleoside analogue licensed for the treatment of HIV infection. Efforts have continuously been made to improve the therapeutic characteristics of this drug, most of them focussed on prodrugs design. Here we describe the anti-HIV-1 activity and cytotoxicity of six novel AZT derivatives namely 3'-azido-3'-deoxy-5'-O-oxalyl-N-valinethymidine, 3'-azido-3'-deoxy-5'-O-oxalyl-N-leucinethymidine, 3'-azido-3'-deoxy-5'-O-oxalyl-N-isoleucinethymidine, 3'-azido-3'-deoxy-5'-O-oxalyl-N-phenylalaninethymidine, 3'-azido-3'-deoxy-5'-O-oxalylthymidine acid, 3'-azido-3'-deoxy-5'-O-isonicotinoylthymidine and 5-chloro-6-hydroxy-5,6-dihydro-3'-azido-3'-deoxythymidine which were perfectly characterized. AZT-Val, AZT-Leu, AZT-iLeu, AZT-Phen, AZT-Ac and AZT-Iso have shown a similar or higher selectivity index than that of AZT itself, in one or both of the different cell cultures used (PBMC and MT2). However, AZT-ClOH showed no anti-HIV activity. These results suggest that using amino acids in the design of AZT derivatives improves AZT activity.

Anti-HIV Agents↗
PubMed2000

Development of an extrachromosomal cloning vector system for use in Borrelia burgdorferi.

Molecular genetic analysis of Borrelia burgdorferi, the cause of Lyme disease, has been hampered by the absence of any means of efficient generation, identification, and complementation of chromosomal and plasmid null gene mutants. The similarity of borrelial G + C content to that of Gram-positive organisms suggested that a wide-host-range plasmid active in Gram-positive bacteria might also be recognized by borrelial DNA replication machinery. One such plasmid, pGK12, is able to propagate in both Gram-positive and Gram-negative bacteria and carries erythromycin and chloramphenicol resistance markers. pGK12 propagated extrachromosomally in B. burgdorferi B31 after electroporation but conferred only erythromycin resistance. pGK12 was used to express enhanced green fluorescent protein in B31 under the control of the flaB promoter. Escherichia coli transformed with pGK12 DNA extracted from B31 expressing only erythromycin resistance developed both erythromycin and chloramphenicol resistance, and plasmid DNA isolated from these transformed E. coli had a restriction pattern similar to the original pGK12. Our data indicate that the replicons of pGK12 can provide the basis to continue developing efficient genetic systems for B. burgdorferi together with the erythromycin resistance and reporter egfp genes.

Borrelia burgdorferi Group↗
PubMed2000

Tn551-mediated insertional inactivation of the fmtB gene encoding a cell wall-associated protein abolishes methicillin resistance in Staphylococcus aureus.

A Tn551 insert in a gene termed fmtB was shown to reduce oxacillin as well as Triton X-100 resistance in highly methicillin-resistant Staphylococcus aureus (MRSA) COL. Backcrosses of fmtB::Tn551 into S. aureus COL and into two genetically distinct MRSA strains, KSA8 and NCTC10443, confirmed the linkage of fmtB::Tn551 with loss of oxacillin resistance. The fmtB gene codes for a protein of a deduced molecular mass of 263 kDa that contains 17 tandem repeats of 75 amino acids and a C-terminal LPXTG cell wall-sorting motif. Immunoblots with anti-FmtB antibodies confirmed its localization in the cell wall fraction. The fmtB gene was mapped downstream of the phosphoglucosamine mutase operon glmM which catalyses formation of glucosamine-1-phosphate. Oxacillin resistance was not restored in fmtB mutants by trans-complementation with fmtB. However, although GlmM production was not affected by fmtB inactivation, oxacillin resistance was increased in fmtB mutants by introducing a plasmid-borne glmM gene, presumably by GlmM overexpression. Interestingly, a similar phenotypic complementation was obtained in fmtB mutants by including substrate level concentrations of N-acetylglucosamine or glucosamine in the growth medium. Inactivation of the fmtB gene seems therefore to have an indirect effect on methicillin resistance which can be relieved by increasing the production of the cell wall precursor glucosamine-1-phosphate.

Bacterial Proteins↗
PubMed2006

Pharmacokinetic-pharmacodynamic relationship of arbekacin for treatment of patients infected with methicillin-resistant Staphylococcus aureus.

Arbekacin is widely used in Japan for the treatment of patients infected with methicillin-resistant Staphylococcus aureus (MRSA). In this study, we have determined the optimal concentration targets of arbekacin for both efficacy and safety. A pharmacokinetic-pharmacodynamic analysis was performed to relate exposure to the drug and clinical cure/improvement or nephrotoxicity. Since we have reported the population pharmacokinetic parameters for arbekacin in the preceding paper (Y. Tanigawara, R. Sato, K. Morita, M. Kaku, N. Aikawa, and K. Shimizu, Antimicrob. Agents Chemother. 50:3754-3762, 2006), individual exposure parameters, such as area under the concentration-time curve (AUC), peak concentration (C(max)), AUC/MIC, C(max)/MIC, and trough concentration (C(min)) were estimated by the Bayesian method. Logistic regression was used to describe the relationship between exposure to the drug and the probability of clinical cure/improvement or nephrotoxicity. For the clinical efficacy analysis, 174 patients confirmed to have an MRSA infection were evaluated. The C(max), C(min), and AUC of arbekacin were associated with the probability of clinical cure/improvement during monotherapy. It was shown that the probability of cure/improvement rose when the C(max) of arbekacin was increased, with an odds ratio of 6.7 for a change in C(max) from 7.9 to 12.5 microg/ml (P = 0.037). For the nephrotoxic risk analysis, 333 patients were included, regardless of whether a pathogen was identified. Logistic regression analysis revealed C(min) and AUC as risk factors of nephrotoxicity (P < 0.005). The estimated probabilities of arbekacin-induced nephrotoxicity were 2.5, 5.2, and 13.1% when the C(min) values were 1, 2, and 5 microg/ml, respectively. The present findings are useful for optimizing the individual dose of arbekacin for the treatment of MRSA-infected patients.

Adolescent↗
PubMed2003

Genetic and phenotypic variations of a resistant Pseudomonas aeruginosa epidemic clone.

From May 1997 to December 2001, a serotype O:6 multidrug-resistant strain of Pseudomonas aeruginosa colonized or infected 201 patients in the University Hospital of Besançon (France). The susceptibility profile of this epidemic clone to fluoroquinolones and aminoglycosides was relatively stable during the outbreak but showed important isolate-to-isolate variations (up to 64-fold) in the MICs of beta-lactams. Analysis of 18 genotypically related isolates selected on a quarterly basis demonstrated alterations in the two DNA topoisomerases II and IV (Thr83-->Ile in GyrA and Ser87-->Leu in ParC) and production of an ANT(2")-I enzyme. Although constitutively overproduced in these bacteria, the MexXY efflux system did not appear to contribute significantly to aminoglycoside resistance. beta-Lactam resistance was associated with derepression of intrinsic AmpC beta-lactamase (with isolate-to-isolate variations of up to 58-fold) and sporadic deficiency in a 46-kDa protein identified as the carbapenem-selective porin OprD. Of the 18 isolates, 14 were also found to overproduce the efflux system MexAB-OprM as a result of alteration of the repressor protein MexR (His107-->Pro). However, complementation experiments with the cloned mexR gene demonstrated that MexAB-OprM contributed only marginally to beta-lactam and fluoroquinolone resistance. Of the four isolates exhibiting wild-type MexAB-OprM expression despite the MexR alteration, two appeared to harbor secondary mutations in the mexA-mexR intergenic region and one harbored secondary mutations in the putative ribosome binding site located upstream of the mexAB oprM operon. In conclusion, this study shows that many mechanisms were involved in the multiresistance phenotype of this highly epidemic strain of P. aeruginosa. Our results also demonstrate that the clone sporadically underwent substantial genetic and phenotypic variations during the course of the outbreak, perhaps in relation to local or individual selective drug pressures.

Aminoglycosides↗
PubMed1971

Protein A mutants of Staphylococcus aureus.

Staphylococcus aureus Cowan I was exposed to nitrosoguanidine or ethyl-methanesulfonate, and survivors were screened on nutrient agar plates containing rabbit anti-protein A serum for loss of protein A production. More than half of all protein A-deficient mutants also lacked nuclease, coagulase, alpha hemolysin, fibrinolysin, mannitol utilization, and the phage-type pattern. Mutants with a spectrum of these properties were also isolated. Induced or spontaneous reversions of the mutants were observed. The properties of the protein A-deficient mutants suggest that synthesis or release (or both) of a number of extracellular products of S. aureus is controlled by a common regulatory mechanism.

Acridines↗
PubMed2000

New method for the selection of multicopy transformants of Pichia pastoris, using 3-amino-1,2,4 triazol.

The methylotrophic yeast Pichia pastoris has been successfully used for the expression of many heterologous proteins. The level of expression of some of these proteins depends on the copy number of the gene inserted into the yeast genome. Several methods have been reported in the past few years for the isolation of multicopy transformants. One of these methods used an expression vector that contains the bacterial kanamycin-resistance gene Tn903kanr, which confers resistance to G418. Here, we report a different selection method in a mutant strain of P. pastoris (his3-) based on the resistance to 3-amino-1,2,4 triazol, with a vector containing the HIS3 gene from Saccharomyces cerevisiae. Using this selection method, we isolated here P. pastoris transformants containing several copies of the dextranase gene (dex) from Penicillium minioluteum.

Amitrole↗
PubMed1999

Pharmacokinetics and therapeutic efficacy of rimantadine in horses experimentally infected with influenza virus A2.

OBJECTIVE: To determine pharmacokinetics of single and multiple doses of rimantadine hydrochloride in horses and to evaluate prophylactic efficacy of rimantadine in influenza virus-infected horses. ANIMALS: 5 clinically normal horses and 8 horses seronegative to influenza A. PROCEDURE: Horses were given rimantadine (7 mg/kg of body weight, i.v., once; 15 mg/kg, p.o., once; 30 mg/kg, p.o., once; and 30 mg/kg, p.o., q 12 h for 4 days) to determine disposition kinetics. Efficacy in induced infections was determined in horses seronegative to influenza virus A2. Rimantadine was administered (30 mg/kg, p.o., q 12 h for 7 days) beginning 12 hours before challenge-exposure to the virus. RESULTS: Estimated mean peak plasma concentration of rimantadine after i.v. administration was 2.0 micrograms/ml, volume of distribution (mean +/- SD) at steady-state (Vdss) was 7.1 +/- 1.7 L/kg, plasma clearance after i.v. administration was 51 +/- 7 ml/min/kg, and beta-phase half-life was 2.0 +/- 0.4 hours. Oral administration of 15 mg of rimantadine/kg yielded peak plasma concentrations of < 50 ng/ml after 3 hours; a single oral administration of 30 mg/kg yielded mean peak plasma concentrations of 500 ng/ml with mean bioavailability (F) of 25%, beta-phase half-life of 2.2 +/- 0.3 hours, and clearance of 340 +/- 255 ml/min/kg. Multiple doses of rimantadine provided steady-state concentrations in plasma with peak and trough concentrations (mean +/- SEM) of 811 +/- 97 and 161 +/- 12 ng/ml, respectively. Rimantadine used prophylactically for induced influenza virus A2 infection was associated with significant decreases in rectal temperature and lung sounds. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of rimantadine to horses can safely ameliorate clinical signs of influenza virus infection.

Administration, Oral↗