• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.828-836
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• 2008

The biocontrol rhizobacterium Pseudomonas sp. M18 can produce two kinds of antibiotics, namely pyoluteorin (Plt) and phenazine-1-carboxylic acid (PCA), and is antagonistic against a number of soilborne phytopathogens. In this study, a luxR-type quorum-sensing regulatory gene, vqsR, was identified and characterized immediately downstream of the Plt gene cluster in strain MI8. A vqsR-inactivated mutant led to a significant decrease in the production of Plt and its biosynthetic gene expression. However, this was restored when introducing the vqsR gene by cloning into the plasmid pME6032 in trans. The vqsR mutation did not exert any obvious influence on the production of PCA and its biosynthetic gene expression and the production of N-acylhomoserine lactones (C4 and C8-HSLs) and their biosynthetic gene rhlI expression. Accordingly, these results introduce VqsR as a regulator of Plt production in Pseudomonas spp., and suggest that the regulatory mechanism of vqsR in strain M18 is distinct from that in P. aeruginosa. In addition, it was demonstrated that vqsR mutation did not have any obvious impact on the expression of Plt-specific ABC transporters and other secondary metabolic global regulators, including GacA, RpoS, and RsmA.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.497-503
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• 2004

In this research, we have performed a T-test to see how the relationship between dependent variable or visual point level and independent variable or visual quantity is in order to clear up the correlation between pattern of visual point and visual quantity by the constituents of a view from a different visual point level and the results are as follows: 1) In case of the character of Mt. Uam landscape of the city, Uamsan is set as a fixed point and about a direction of view(D), the north is a datum point from which the range of direction is distributed within 1800 westwardly and the visual range(R) is also within 2000m. An elevation is an average of 7.40 and the average story of the buildings is 3.85. Here the height of a story is about 4m so the average of the visual point difference is estimated at 15.4m. 2) The type of visual point is divided into the intersection group and the front of the highly used public buildings group. Double intersection types account for about 78.80%(52 spots) which forms a majority part of LCP. 3) The analysis of the difference of visual point level divided by eye level and that of the top of the buildings has been proved that there's a sharp difference resulted from t-test at 1 % significant level. The significant difference of elevation from height difference(l5.93m), however, has not been shown. 4) From the result of T-test about visual quantity by the elements of a view from a different visual point level, the visual quantity of mountain(VQM), sky(VQS), ground(VQG) is significant at about 1% each and that of building(VQB) is at about 5%. The difference in visual quantity of a mountain by the visual point level is at about 4% which can meet a marginal level of LCP necessary for evaluation of mountainscape.