We determined the macrolide resistance phenotypes of 241 clinical isolates of erythromycin-resistant enterococci (MICs, >1 g/ml), including 147 Enterococcus faecalis strains and 94 Enterococcus faecium strains, collected from a hospital in Seoul, Korea, between 1999 and 2000. By the erythromycin (40 g)-josamycin (100 g) double-disk test, 93 strains were assigned to the constitutive macrolide, lincosamide, and streptogramin B (MLS B ) resistance (cMLS B ) phenotype, and the remaining 148 strains were assigned to the inducible MLS B resistance (iMLS B ) phenotype. Of the strains with the iMLS B phenotype, 36 exhibited a reversibly inducible MLS B (riMLS B ) phenotype, i.e., blunting of the erythromycin zone of inhibition, which indicates that the 16-membered-ring macrolide josamycin is a more effective inducer than the 14-membered-ring macrolide erythromycin. Sequence analysis of the regulatory regions of the erm(B) genes from all of the strains exhibiting the riMLS B phenotype revealed not only erm(Bv) [where v represents variant; previously erm(AMR)] (n ‫؍‬ 13), as reported previously, but also three kinds of erm(B) variants, which were designated erm(Bv1) (n ‫؍‬ 17), erm(Bv2) (n ‫؍‬ 3), and erm(Bv3) (n ‫؍‬ 3), respectively. In lacZ reporter gene assays of these variants, the 16-membered-ring macrolide tylosin had stronger inducibility than erythromycin at >0.1 g/ml. These findings highlight the versatility of erm(B) in induction specificity.Cross-resistance to macrolide, lincosamide, and streptogramin B (MLS B ) antibiotics is mediated by 23S rRNA mutations or the erm genes, which encode 23S rRNA methylases. The expression of MLS B resistance by the erm genes can be either constitutive or inducible, depending on the regulatory region located upstream of the structural gene. In inducible resistance, the specificity of induction differs according to the nature of the regulatory region. The erm(A) and erm(C) genes, the predominant determinants of MLS B resistance in staphylococci, are most often induced in the presence of 14-membered-ring macrolides and the lincosamide celesticetin, but not the 16-membered-ring macrolides and the lincosamide lincomycin (1,8,23,24). Mutants of Staphylococcus aureus selected in the laboratory were reported to be induced by lincomycin and the 16-membered-ring macrolide carbomycin (22); and a recently found clinical strain of S. aureus with erm(A) had inducible cross-resistance to the 14-membered-ring macrolide erythromycin, the lincosamides clindamycin and lincomycin, and the streptogramin B quinupristin (5). The erm(D) gene is induced by the 14-membered-ring macrolides erythromycin and oleandomycin but is not induced by either the 16-membered-ring macrolide tylosin or the lincosamides clindamycin and lincomycin (6). Transcription of the erm(S) gene in the tylosin producer Streptomyces fradiae is autoinducible by tylosin (10). The erm(V) gene from Streptomyces viridochromogenes is induced by the 14-and 16-membered-ring macrolides and celesticetin (8). Interestingly, all MLS B antibio...

The purpose of this study is to analyse the tourists' spatiotemporal behaviour at the rural festival using the theory and tracking methods of time geographies and the smart phone application based on global positioning system data. Main results show that most festival tourists visit only the entrance and central spaces, walking along on the same paths, while only a small number of visitors visit the regional commercial area, including the traditional market, main streets in the downtown area, although their tickets allow them to visit these spaces. Based on the time and space density analysis, this study draws the time -space aquarium of the Sancheoneo Ice Festival and can find a spatiotemporal concentration and limitation of socio-economic sustainability in rural tourism using festival as a development booster. Therefore, festival planners and policy-makers should focus on these limited spatial movement patterns and temporal flows of visitors in communitybased tourism.

Phorbol 12-myristate 13-acetate (PMA)-induced differentiation of human erythroleukemic K562 cells is characterized by growth arrest, morphological change, and expression of megakaryocyte-specific proteins. We examined the possible involvement of cell cycle regulators with PMA-induced growth arrest and megakaryocytic differentiation of K562 cells. The concentrations of cyclin D1 and p21Waf1/Cip1 were dramatically increased, whereas those of cyclin B1 and cdc2 were decreased, by PMA treatment. The concentrations of most cyclin-dependent kinases (Cdk2, Cdk4, and Cdk6), however, were unchanged by PMA treatment. PD98059, a specific inhibitor of MEK1, partially prevented the increase in cyclin D1 caused by PMA and fully reversed the down-regulation of cyclin B1 protein seen in response to PMA treatment. Thus, it is demonstrated here that the PMA-mediated changes of cyclin D1 and B1 are the result of a persistent increase in extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) activity.

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