Structure of the high mannose oligosaccharides of a human IgM myeloma protein. I. The major oligosaccharides of the two high mannose glycopeptides.
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The structures of the predominant high mannose oligosaccharides present in a human IgM myeloma protein (Patient Wa) have been determined. The IgM glycopeptides, produced by pronase digestion, were fractionated on DEAE-cellulonalysis shows that glycopeptide I contains Asn, Pro, Ala, Thr, and His and glycopeptide II contains Asn, Val, and Ser, which are the same amino acids found in the sequences around Asn 402 and Asn 563 respectively, to which high mannose oligosaccharides are attached in IgM (Patient Ou) (Putnman, F.W., Florent, G., Paul, C., Shinoda, T., and Shimizu, A. (1973) Science 182, 287-290). The high mannose glycopeptides in IgM (Wa) exhibit heterogeneity in the oligosaccharide portion. Structural analysis of the major oligosaccharides indicates that the simplest structure is: (see article of journal). The larger oligosaccharides present have additional mannose residues linked alpha 1 yields 2 to terminal mannose residues in the above structure. Glycopeptide I contains primarily Man5 and Man6 species, while glycopeptide II contains Man6 and Man8 species. The two Man6 oligosaccharides have different branching patterns. (+info)
Antimicrobial susceptibility patterns of enterococci causing infections in Europe. The European VRE Study Group.
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In vitro susceptibilities of 4,208 enterococci (83% Enterococcus faecalis isolates, 13.6% Enterococcus faecium isolates, and 3.4% isolates of other species) from patients in 27 European countries towards 16 antibiotics were determined. High-level resistance to gentamicin varied by country (range, 1 to 49%; mean, 22.6% +/- 12. 3%) and per species (19.7% E. faecalis isolates, 13.6% E. faecium isolates, 3.4% by other species). Vancomycin resistance was detected in 0.06% E. faecalis, 3.8% E. faecium, and 19.1% isolates of other species. All enterococci were susceptible to LY 333328 and everninomicin, and 25% of E. faecalis isolates and 85% of other enterococci were susceptible to quinupristin-dalfopristin. The MIC of moxifloxacin and trovafloxacin for ciprofloxacin-susceptible E. faecalis at which 90% of the isolates were inhibited was 0.25 to 0.5 microg/ml. (+info)
Phenotypic distinction in Enterococcus faecium and Enterococcus faecalis strains between susceptibility and resistance to growth-enhancing antibiotics.
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Susceptibility of Enterococcus faecium and Enterococcus faecalis strains from animals and foods to growth-promoting antibiotics used in animal feed was tested by the agar dilution technique. Acquired resistance to bacitracin, narasin, tylosin, and virginiamycin was seen for both species, and for E. faecium, resistance to avilamycin and avoparcin was also seen. Drawing the distinction between susceptibility and resistance based on frequency distributions of MICs was easy with avoparcin, avilamycin, and tylosin but difficult with virginiamycin and to some extent also with bacitracin and narasin. (+info)
Glycopeptide-intermediate Staphylococcus aureus: evaluation of a novel screening method and results of a survey of selected U.S. hospitals.
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Isolates of Staphylococcus aureus with decreased susceptibilities to glycopeptide antimicrobial agents, such as vancomycin and teicoplanin, have emerged in the United States and elsewhere. Commercially prepared brain heart infusion agar (BHIA) supplemented with 6 microg of vancomycin per ml was shown in a previous study to detect glycopeptide-intermediate S. aureus (GISA) with high sensitivity and specificity; however, this medium, when prepared in-house, occasionally showed growth of vancomycin-susceptible control organisms. This limitation could significantly impact laboratories that prepare media in-house, particularly if they wished to conduct large surveillance studies for GISA. Therefore, a pilot study to detect GISA was performed with vancomycin-containing Mueller-Hinton agar (MHA) prepared in-house in place of commercially prepared BHIA. MHA was selected for this study because this medium is widely available and well standardized. The results of the pilot study showed that supplementation of MHA with 5 microg of vancomycin per ml was both a sensitive and a specific method for screening for GISA isolates. This method was used to screen for GISA among 630 clinical isolates of methicillin-resistant S. aureus collected during 1997 from 33 U.S. hospitals. Although 14 S. aureus isolates grew on the screening agar, all were vancomycin susceptible (MICs were +info)
A method for S- and O-palmitoylation of peptides: synthesis of pulmonary surfactant protein-C models.
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A method for O- and S-palmitoylation of non-protected peptides has been developed. The peptides are treated with excess of palmitoyl chloride in 100% trifluoroacetic acid for 10 min at room temperature. The acidic conditions prevent acylation of amino groups, which is only significant after prolonged treatment (hours to days). The tripeptides Gly-Cys-Phe and Gly-Ser-Phe were converted into the respective S- and O-palmitoylated compounds, and the hydrophobic pulmonary surfactant protein-C model peptides, LRIPCCPVNLKRLLVVV [SP-C(1-17)] and FGIPSSPVLKRLLILLLLLLLILLLILGALLMGL [SP-C(Leu)] were converted into their respective S,S- and O,O-dipalmitoylated peptides. The reactions were virtually quantitative, and the palmitoylated peptides were isolated in about 75-80% yield after reversed-phase HPLC purification. CD spectroscopy showed that S, S-dipalmitoylation of SP-C(1-17) affects the peptide secondary structure (substantial increase in the alpha-helix content) in dodecylphosphocholine micelles. (+info)
Endothelin converting enzyme is located on alpha-actin filaments in smooth muscle cells.
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OBJECTIVE: Endothelin converting enzyme is the key enzyme in the generation of endothelin-1 from big-endothelin-1. The mature endothelin-1 is a potent vasoconstrictor which also promotes mitogenesis and proliferation of smooth muscle cells. The objectives were to demonstrate in smooth muscle cells the presence of a phosphoramidon-sensitive endothelin converting enzyme activity, reveal the subcellular localization of the enzyme protein and determine the effects of the metalloproteinase inhibitor, phosphoramidon, the lysosomotrophic drug, chloroquine, and colchicine on the cycling pathway of the enzyme. METHODS: Subcellular localization of endothelin converting enzyme on human smooth muscle cells and the rat cell line, A7r5, was by immunofluorescence and confocal microscopy or by biotinylation of cell cultures and immunoblotting, after treatment of cell cultures with cytochalasin D, colchicine, chloroquine and phosphoramidon. Converting enzyme activity was determined by high performance liquid chromatographic assay. RESULTS: We detected phosphoramidon-sensitive endothelin converting enzyme activity in smooth muscle cells. In addition to its plasma membrane location, for the first time we revealed a striking co-localization of endothelin converting enzyme and alpha-actin filaments in smooth muscle cells. Colchicine treatment results in a perinuclear accumulation of endothelin converting enzyme. An increased level of endothelin converting enzyme protein was shown to be present in smooth muscle cells which had been grown in the presence of phosphoramidon or chloroquine. CONCLUSION: The 120 kDa endothelin converting enzyme co-localizes with alpha-actin in smooth muscle cells and resembles that found in endothelial cells in that it is present on both the plasma membrane and intracellularly. (+info)
Characterization of methicillin-resistant Staphylococcus aureus isolated from dogs in Korea.
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Twelve strains of the methicillin-resistant Staphylococcus aureus (MRSA) recovered from hospitalized dogs were analyzed for in vitro antimicrobial susceptibility and virulence, and were genetically characterized by pulsed-field gel electrophoresis (PFGE). Antibiotic susceptibility test showed that nearly all isolates were resistant to beta-lactam antibiotics tested and all the strains were fully susceptible to glycopeptides. There were no inhibitory activities among the aminoglycosides. The 50% lethal dose (LD50) was determined by intraperitoneal injection of cell suspensions and estimated by the Spearman-Karber method. The mouse lethality of MRSA and methicillin-susceptible S. aureus (MSSA) was not significantly different in both normal and cyclophosphamide-treated mice (p>0.05), indicating that they were equally virulent. There was a great difference in the incidence of toxin production between the MRSA and MSSA group; 83.3% (10 of 12) of the MRSA and 14.3% (1 of 7) of the MSSA were toxin producers. The predominant types produced by MRSA was B. All the MRSA strains were capsular type 5 producers, while of 7 MSSA strains, four were type 5, one for type 8, and two were nontypeable. Based on the PFGE analysis, the 12 MRSA isolates generated 9 to 11 fragments in the size range of <48.5 to 630.5 kb, and yielded 6 different patterns. The results indicated that production of toxin and capsule type do not play a role in the pathogenicity to mouse and PFGE is a valuable tool for the characterization of MRSA. This report is the first such cases in the veterinary literature in Korea and may indicate the frequent emergence of MRSA in veterinary clinic hereafter. (+info)
Antimicrobial susceptibilities and serogroups of clinical strains of Clostridium difficile isolated in France in 1991 and 1997.
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Glycopeptides (vancomycin and teicoplanin) and metronidazole are the drugs of choice for the treatment of Clostridium difficile infections, but trends in susceptibility patterns have not been assessed in the past few years. The objective was to study the MICs of glycopeptides and metronidazole for unrelated C. difficile strains isolated in 1991 (n = 100) and in 1997 (n = 98) by the agar macrodilution, the E-test, and the disk diffusion methods. Strain susceptibilities to erythromycin, clindamycin, tetracycline, rifampin, and chloramphenicol were also determined by the ATB ANA gallery (bioMerieux, La Balme-les-Grottes, France). The MICs at which 50% of isolates are inhibited (MIC(50)s) and MIC(90)s of glycopeptides and metronidazole remained stable between 1991 and 1997. All the strains were inhibited by concentrations that did not exceed 2 microgram/ml for vancomycin and 1 microg/ml for teicoplanin. Comparison of MICs determined by the agar dilution method recommended by the National Committee for Clinical Laboratory Standards and the E test showed correlations (+/-2 dilutions) of 86. 6, 95.9, and 99% for metronidazole, vancomycin, and teicoplanin, respectively. The E test always underestimated the MICs. Strains with decreased susceptibility to metronidazole (MICs, >/=8 microgram/ml) were isolated from six patients (n = 4 in 1991 and n = 2 in 1997). These strains were also detected by the disk diffusion method (zone inhibition diameter, /=1 microgram/ml), clindamycin (MICs, >/=2 microgram/ml), tetracycline (MICs, >/=8 microgram/ml), rifampin (MICs, >/=4 microgram/ml), and chloramphenicol (MICs, >/=16 microgram/ml) was observed in 64.2, 80.3, 23.7, 22.7, and 14.6% of strains, respectively. Strains isolated in 1997 were more susceptible than those isolated in 1991, and this trend was correlated to a major change in serogroup distribution. Periodic studies are needed in order to detect changes in serogroups and the emergence of strains with decreased susceptibility to therapeutic drugs. (+info)