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High Prevalence of Antimicrobial Resistance among Clinical Streptococcus pneumoniae Isolates in Asia (an ANSORP Study). Jae-Hoon Song, 2004.A total of 685 clinical Streptococcus pneumoniae isolates from patients with pneumococcal diseases were collected from 14 centers in 11 Asian countries from January 2000 to June 2001 . The in vitro susceptibilities of the isolates to 14 antimicrobial agents were determined by the broth microdilution test . Among the isolates tested, 483 (52.4%) were not susceptible to penicillin, 23% were intermediate, and 29.4% were penicillin resistant (MICs  2 mg/liter) . Isolates from Vietnam showed the highest prevalence of penicillin resistance (71.4%), followed by those from Korea (54.8%), Hong Kong (43.2%), and Taiwan (38.6%) . The penicillin MICs at which 90% of isolates are inhibited (MIC90s) were 4 mg/liter among isolates from Vietnam, Hong Kong, Korea, and Taiwan . The prevalence of erythromycin resistance was also very high in Vietnam (92.1%), Taiwan (86%), Korea (80.6%), Hong Kong (76.8%), and China (73.9%) . The MIC90s of erythromycin were >32 mg/liter among isolates from Korea, Vietnam, China, Taiwan, Singapore, Malaysia, and Hong Kong . Isolates from Hong Kong showed the highest rate of ciprofloxacin resistance (11.8%), followed by isolates from Sri Lanka (9.5%), the Philippines (9.1%), and Korea (6.5%) . Multilocus sequence typing showed that the spread of the Taiwan19F clone and the Spain23F clone could be one of the major reasons for the rapid increases in antimicrobial resistance among S . pneumoniae isolates in Asia . Data from the multinational surveillance study clearly documented distinctive increases in the prevalence rates and the levels of antimicrobial resistance among S . pneumoniae isolates in many Asian countries, which are among the highest in the world published to date .
Large-Scale Population Structure of Human Commensal Escherichia coli Isolates. Patricia Escobar-Páramo, 2004. The Membrane-Associated Methane Monooxygenase (pMMO) and pMMO-NADH:Quinone Oxidoreductase Complex from Methylococcus capsulatus Bath. Dong-W. Choi, 2003.Improvements in purification of membrane-associated methane monooxygenase (pMMO) have resulted in preparations of pMMO with activities more representative of physiological rates: i.e., >130 nmol · min-1 · mg of protein-1 . Altered culture and assay conditions, optimization of the detergent/protein ratio, and simplification of the purification procedure were responsible for the higher-activity preparations . Changes in the culture conditions focused on the rate of copper addition . To document the physiological events that occur during copper addition, cultures were initiated in medium with cells expressing soluble methane monooxygenase (sMMO) and then monitored for morphological changes, copper acquisition, fatty acid concentration, and pMMO and sMMO expression as the amended copper concentration was increased from 0 (approximately 0.3 µM) to 95 µM . The results demonstrate that copper not only regulates the metabolic switch between the two methane monooxygenases but also regulates the level of expression of the pMMO and the development of internal membranes . With respect to stabilization of cell-free pMMO activity, the highest cell-free pMMO activity was observed when copper addition exceeded maximal pMMO expression . Optimization of detergent/protein ratios and simplification of the purification procedure also contributed to the higher activity levels in purified pMMO preparations . Finally, the addition of the type 2 NADH:quinone oxidoreductase complex (NADH dehydrogenase [NDH]) from M . capsulatus Bath, along with NADH and duroquinol, to enzyme assays increased the activity of purified preparations . The NDH and NADH were added to maintain a high duroquinol/duroquinone ratio . Mass Distribution and Spatial Organization of the Linear Bacterial Motor of Spiroplasma citri R8A2. Shlomo Trachtenberg, 2003.In the simple, helical, wall-less bacterial genus Spiroplasma, chemotaxis and motility are effected by a linear, contractile motor arranged as a flat cytoskeletal ribbon attached to the inner side of the membrane along the shortest helical line . With scanning transmission electron microscopy and diffraction analysis, we determined the hierarchical and spatial organization of the cytoskeleton of Spiroplasma citri R8A2 . The structural unit appears to be a fibril,  5 nm wide, composed of dimers of a 59-kDa protein; each ribbon is assembled from seven fibril pairs . The functional unit of the intact ribbon is a pair of aligned fibrils, along which pairs of dimers form tetrameric ring-like repeats . On average, isolated and purified ribbons contain 14 fibrils or seven well-aligned fibril pairs, which are the same structures observed in the intact cell . Scanning transmission electron microscopy mass analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified cytoskeletons indicate that the 59-kDa protein is the only constituent of the ribbons .
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