• Journal of Microbiology and Biotechnology
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• v.4 no.3
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• pp.165-170
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• 1994

An efficient and convenient method of introducing transposable elements into acetic acid bacteria was developed by the method of conjugal transfer. The ampicillin-resistant strain, Acetobacter sp. HA, was selected to be conjugated with two E. coli strains, WA803 containing pGS9 and AC8001 harboring pJB4JI. The Tn5 containing suicide vector pGS9 or pJB4JI, was transferred from E. coli to Acetobacter sp. HA and kanamycin-ampicillin-resistant transconjugants obtained at high frequencies. The conjugal frequencies of pGS9 and pJB4JI were 6.20$\times$$l0^{-1} and 2.79$\times$l0{-1}$ per recipient, respectively. The transfer method was applied on four different strains of Acetobacter. The conjugal transfer frequencies ranged from 2.00$\times$$l0^{-2} to 4.45$\times$l0^{-8}$ per recipient in the three strains. Some transconjugants tested were found to contain Tn5 DNA in their genomes and this was confirmed by Southem blot analysis. This is the first study which shows that Tn5 mutagenesis can be applied to successfully isolate mutants of Acetobacter genus.

• Microbiology and Biotechnology Letters
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• v.17 no.3
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• pp.183-187
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• 1989

The bacteriophage Mu and transposon Tn5 containing plasmid pJB4JI-transferred transposon Tn5 to Caulobuter crescentus. When several thousand of transposon Tn5 insertion mutants were examined, we found auxotrophic and motility mutants at frequencies of 2％ and 3％, respectively. Transposition of transposon Tn5 was analyzed by the reverse field electrophoresis and Southern hybridization. The results indicated that transposon Tn5 was randomly inserted to Caulobuter crescentus chromosome but the plasmid vector, pJB4JI, was not maintained.

• Food Science and Preservation
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• v.22 no.4
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• pp.607-612
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• 2015

The aim of this research was to investigate the whitening effects of rutin and rutin metabolites including 3,4-dihydroxyphenyl acetic acid (DHPAA), 3-hydroxyphenyl acetic acid (HPAA), 3,4-dihydroxytolene (DHT) and homovanillic acid (HVA). The potent whitening effect of rutin and rutin metabolites were determined by mushroom tyrosinase inhibition assay and expressed as the half maximal inhibitory concentration ($IC_{50}$) against tyrosinase activity in vitro. The HVA showed the highest inhibitory effect ($IC_{50}=37.10{\mu}M$) of tyrosinase activity, followed by DHPAA ($IC_{50}=45.87{\mu}M$), HPAA ($IC_{50}=50.96{\mu}M$), rutin ($IC_{50}=57.98{\mu}M$), and DHT ($IC_{50}=66.09{\mu}M$), respectively. To evaluate cell cytotoxicity, MTT assay was performed with JB6 P+ mouse epidermal cells and expressed as a relative percentage of untreated control. The results showed that rutin and rutin metabolites had no cytotoxic effects on JB6 P+ cells up to $100{\mu}M$ except for DHT (up to $50{\mu}M$). These results suggests that rutin metabolites may be utilized as a potential tyrosinase inhibitors and the whitening agents for the future.

• The Korean Journal of Food And Nutrition
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• v.28 no.1
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• pp.111-118
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• 2015

In summary, the rutin metabolite DHT significantly reduced EGF-induced neoplastic transformation in JB6 P+ cells. This inhibition was mediated mainly by blocking the Raf/MEK/ERK signaling pathway and subsequent suppression of AP-1 activities. DHT attenuated Raf-1 kinase activity by directly binding to Raf-1 in vitro and ex vivo. Taken together, these results suggest that Raf-1 may be a critical molecular target to suppress DHT-induced neoplastic transformation, which is mainly attributable to the chemopreventive potential of several foods containing rutin.