• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.593-598
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• 1994

A bacterium KL-57 which exhibited biosurfactant activity was isolated. This bacterium was identified as Bacillus subtilis. The biosurfactant-producing gene of B. subtilis KL-57 was cloned into R subtilis MI113 by using plasmid pTB523. The plasmid DNA from the clone was found to carry a 18 kb PstI insert. The biosurfactant-producing gene was cleaved into 4 fragments by SmaI, 3 fragments by PvulI or EcoRl, 4 fragments by PvulI and EcoRI double digestion, 5 fragments by AccI, and 2 fragments by KpnI, HindIII or BamHI. By subcloning the 18 kb Pstl insert, a 2.3 kb EcoRl fragment conferred the biosurfactant producing activity on B. subtilis cells. The 2.3 kb had one HindIII cleave site. But Two fragments, which corresponds HindIII/EcoRl termini, exhibited no biosurfactant activity.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.91-95
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• 1994

EagBI is a type II restriction endonuclease from Enterobacter agglomerans strain CBNU45 isolated from soil. EagBI was partially purified by DEAE-cellulose, phosphocellulose P11 and hydroxylapatite column chromatography. EagBI recognizes and cleaves the sequence 5'-CGAT${\downarrow}$CG-3' and generates 2-base 3'-protruding cohesive ends. The optimal reaction conditions of EagBI are 10 mM Tris-HCl (pH 7.8), 6-10 mM $MgCl_2$, at 37 ${\circ}C$. The enzyme is maximally active in the absence of NaCl, able to cleave both $dam^-$ and $dam^+$ DNAs, and sensitive to heat treatment (at 65 ${\circ}C$ for 10 min). Therefore, although EagBI is an isoschizomer of PvuI, it is more useful than PvuI in respect of the NaCl requirement and heat-stability.

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.468-475
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• 1988

The cloned B. subtilis cdd gene encoding cytidine/2'deoxycytidine deaminase (EC 3.5.4.5) was expressed in the cdd deficient B. subtilis mutant ED40. The gene was isolted from the cdd complementing plasmid pSO21, and inserted into the EcoR1/Pvu1 sites of pGB215-110 ΔB, which is a temperature sensitivie E. coli-B. subtilis shuttle vector. In the transformed B. subtilis ED4O harboring the resulting plasmid pSO100, cdd was expressed at several hundred fold elevated levels, and the cytidine deaminase activity in E. coli containing pSO100 was twice the level in B. subtilis/pSO0100. The Km value for cytidine of the partially purified enzyme is 1.88$\times$10$^{-4}$M at pH 7.0 and the V$_{max}$ = 11.1 $\mu$mol/min/mg of protein. The enzyme was completely inhibited by 0.1M mercaptoethanol and HgCl$_2$. The inhibition by p-chrolomercurybenzoic acid showed a Ki = 5 uM. These results suggest that sulfhydryl reagents block an active site thiol group, and/or disturb the formation of the tetrameic holoenzyme.