• Korean Journal of Microbiology
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• v.39 no.3
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• pp.135-140
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• 2003

Bacillus sp. secretes high levels of extracellular enzymes into the culture medium. The signal recognition particle (SRP) and the SRP receptor play a central role in targeting pre secretory proteins to the translocase. By the analysis of the DNA microarray of B. lentimorbus WJ5, it was detected that WJ5m12, antifungal activity deficient mutant induced by gamma radiation, had a down-regulated expression of the SRP receptor gene (B. subtitis srb homologue, srbL). To determine the relationship of SRP receptor to antifungal activity, srbL of B. lentimorbus WJ5 was amplified by PCR and ligated into pQE30 vector, and then transferred into WJ5m12. The transformant, WJ5m12::srbL, recovered the antifungal activity. From the 2-DE analysis, the several presecretory proteins accumulated in the mutant cell and decreased to a level of the wild type in WJ5m12::srbL. It seems that the srbL could play an important role in the secretion of the antifungal activity related proteins of B. lentimorbus WJ5.

• Korean Journal of Environmental Biology
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• v.21 no.3
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• pp.276-285
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• 2003

To control pythium root rot, Bacillus lentimorbus WJ5a17 with high anti-fungal activity against Pythium ultimum was induced from B. lentimorbus WJ5 by gamma radiation ($^{60}Co$). The biocontrollers of FWJ5 and FWJ5a17 were formulated ($1.0\times 10^{11}$) with B. lentimorbus WJ5 and WJ5a17, respectively, The population density of FWJ5 and FWJ5a17 maintained highly up to $1.0\times 10^{9}$ CFU $g^{-1}$ in nursery and field soils until 30 days after treatment. P. ultimum spores germination were inhibited 71.0% and 81.4% by FWJ5 and FWJ5a17, respectively. Pythium root rot of yea pepper, Chinese cabbage and radish were significantly (p < 0.05) controled by one time treatment of FWJ5 and FWJ5a17.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.472-477
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• 2004

To study the radiation related gene expression in mutants of Bacillus lentimorbus WJ5 induced by gamm radiation, the simultaneous gene expression was analyzed by DNA micro array. We constructed DNA chips including two thousand randomly digested genome spots of B. lentimorbus WJ5 and compared its quantitative aspect with seven mutants induced by gamma radiation $(^{60}/Co)$. From the cluster analysis of gene expression pattern, totally 408 genes were expressed and 27 genes were significantly upregulated by the gamma radiation in all mutants. Especially, genes involved in repair (mutL, mutM), energy metabolism (acsA, sdhB, pgk, yhjB, citB), protease (npr), and reduction response to oxidative stress (HMM) were simultaneously upregulated. It seems that the induction of the direct and/or indirect repair related genes in mutants induced by gamma radiation could be remarkably different from the adaptive responses against acute exposure to radiation.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.141-147
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• 2003

The simultaneous expression levels of antifungal activity related genes was analyzed by DNA microarray. We constructed DNA chips contained 2,000 randomly digested genome spots of the antifungal bacterium of Bacillus lentimorbus WJ5 and compared its quantitative aspect with 7 antifungal activity deficient mutants induced by gamma radiation ($^{60}Co$). From the analysis of microarray hybridization by the Gene Cluster (Michael Eisen, Stanford Univ.), totally 408 genes were expressed and 20 genes among them were significantly suppressed in mutants. pbuX (xanthine permease, K222), ywbA (phosphotransferase system enzyme II, K393), ptsG (PTS glucose specific enzyme II ABC component, K877), yufO (ABC transporter (ATP-binding protein), K130l), and ftsY (signal recognition particle (docking protein), K868) were simultaneously down-regulated in all mutants. It suggested that they were supposed to be related to the antifungal activity of B. lentimorbus WJ5.

• Journal of Microbiology
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• v.43 no.3
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• pp.308-312
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• 2005

The global RNA transcription profiles of Bacillus lentimorbus WJ5 under an in vitro co-culture with Colletotrichum gloeosporioides were analyzed in order to study the antagonistic bacteria-fungi interactions. Using a filter membrane system, B. lentimorhus WJ5 was exposed to the spores of C. gloeosporioides at the late exponential stage. The transcription profiles of the B. lentimorhus WJ5, both with and without a challenge from C. gloeosporioides, were analyzed using custom DNA chips containing 2,000 genome fragments. A total of 337 genes were expressed, with 87 and 47 up- and down-regulated, respectively. Of these, 12 genes, which were involved in central carbon metabolisms, and 7 from minor catabolism were relatively highly up-regulated (> 10 fold) and down-regulated (< 0.2 fold), respectively. Nine genes, which were thought to be related to the antifungal activity, were also up-regulated, but their levels were not so high (2.0 - 9.7 folds). From the results, during the early stage of the co-culture of B. lentimorbus WJ5 and C. gloeosporioides, nutrient competition seemed to occur; therefore, the genes from central carbon metabolisms could be up-regulated, while those from minor catabolism could be down-regulated.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2005.12a
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• pp.114-114
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• 2005