• Applied Biological Chemistry
• /
• v.36 no.6
• /
• pp.562-566
• /
• 1993

The conditions required for plant transformation through the electroporation system and for the electrofusion of the prtoplasts were investigated for geranium (Pelargonium zonale hybrids). The optimum condition for electroporation was 1.77 kV/cm for $40\;{\mu}sec$ under which 70% of the protoplasts were viable and 58% of the viable protoplasts were stained with methylene blue. The pBin19 DNA plasmid used as a carrier vector was isolated from E.coli $DH5{\alpha}$ strain, purified, identified by the electrophoresis on agarose gel and electroporated into the protoplasts. The KM8 liquid medium gave better cell division than any other media. One MHz of AC frequency with 40 V/cm of amplitude for 15 sec followed by 0.5 kV/cm of DC amplitude for $60\;{\mu}sec$ was most efficient for the electrofusion of protoplasts.

• Korean Journal of Microbiology
• /
• v.28 no.1
• /
• pp.19-26
• /
• 1990

To examine the effects of sequence variations near the transcriptional start site on the rate of formation of the open complexes at bacteriophage $\lambda P_{R}$ promoter, two mutant promoters were created by site-specific mutagenesis using synthetic oligonucleotides. Mutant I coatains changes at positions -3 and -4 from TT to CC, thus having a 6-bp long G/C stretch between -10 region and transciptional start site (+1). Mutant II has changes at positions -5 and -6 from GG to AA, thereby having a 9-bp long A/T stretch between positions -11 and -3. Selective filter binding assays were performed to measure the rate of formation of the open complexes between the wild-type or two mutant $P_{R}$ promoters on 664 bp fragments and E. coli RNA polymerase at two temperatures. At 37.deg.C, the wild-type and two mutants showed similar rates for the formation of open complex. The second order rate constant $k_{a}$ and $\tau _{int}$, as determined from the .tau.-plot analysis, were $(6.0\pm0.4)\times10^{6}M^{-1}sec^{-1}$ and $11\pm5$sec, respectively. At 18.deg.C, however, the wild-type and two mutant promoters showed differences in the kinetic parameters. k for the wild-type promoter was (2.2$\pm$0.1)\times 10^{6}M^{-1}sec^{-1}$ and $\tau _{int}$ was 76$\pm$sec. Mutant I and II exhibited differences mainly in the rate of isomerization ($\tau_{int,I}=91\pm$10 sec, int,II=34$\pm$ sec), whereas the second order rate constant $k_{a}$ was similar to the wild type value. This result implies that at $18^{\circ}C$, the isomerization rate is determined by both protein conformational change and DNA melting, which are separable kinetically according to the 3-step mechanism of Roe et al.(1984,1985), and that the base changes affected mainly the rate of DNA melting as predicted.lting as predicted.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.2
• /
• pp.515-527
• /
• 2014

This study conducted experiment for understanding engineering characteristics of domestic sands by examining standard sand and sand from Yokji Island and Nakdong River in terms of confining pressure, $K_0$, over consolidation and relative density factors through triaxial compression test. The test showed that deviator stress by strain positively changed as confining pressure and relative density grow while $K_0$ and over consolidation factors do not directly correlated with it. Angle of internal friction decreases as confining pressure increases which strengthens contact force between particles, and declines as relative density drops, whereas $K_0$ and over consolidation factors hardly affect the results. When it comes to volumetric strain, volume expansion decreases as confining pressure increase due to crushability and rearrangement of particles while $K_0$ and over consolidation shows same movement unconditionally, and relative density appears compressed as it grows at the beginning however it expands as axial strain increases. Modulus of elasticity ($E_{sec}$) by strain has tendency into convergence resulting in initial secant modulus of elasticity ($E_{ini}$) > secant modulus of elasticity($E_{sec}$) > tangent modulus of elasticity ($E_{tan}$). On the other hand, it grows as confining pressure and relative density increase while indicating similar modulus of elasticity ($E_{sec}$) regarding on $K_0$ and over consolidation. Slope of critical line (M) tended to decrease as confining pressure increases, follow same line according to $K_0$, confining pressure and relative density, and increase as relative density grows.

• Applied Biological Chemistry
• /
• v.11
• /
• pp.137-141
• /
• 1969

In order to obtain amino acids and nucleic acid derivatives from adenine auxotrophic mutants of Bacillus subtilis and Escherichia coli, vitamin, nucleic acid analogue, streptomycin as well as ultraviolet light were adopted for the production of adenine auxotrophic mutants and the results showed efficient production of desired mutants. 1. Ultraviolet ray $(2530\;{\AA}\;2080\;erg/mm^2)$ irradiation to Bacillus subtilis and E. coli at a distance of 30 cm for 80-90 sec. and for 15-20 sec. respetively induced four and eight strains of auxotrophic mutants. 2. Treatment of aminopterine$(200\;{\mu}g/ml)$ inhibited the growth of Bacillus sultilis significantly but a subsequent irradiation of ultraviolet light at the above mentioned conditions induced six times as much mutants as compared to the irradiation alone. In case of E. coli a similar tendency was observed with treatment of streptomycin$(200\;{\mu}g/ml)$ with doubled induction rate of adenine auxotrophic mutants as compared to the irradiation alone.

• Textile Coloration and Finishing
• /
• v.9 no.3
• /
• pp.18-26
• /
• 1997

Polyester microfiber fabrics were decomposed at 100, 110, and 12$0^{\circ}C$ in saturated CaO/ethylene glycol solutions(CaO/EG), and the characteristics of decomposition kinetics were discussed in comparison to those by hot aqueous hydroxide solution(NaOH). The Arrhenius pre-exponential factor(A) was 9.17x $10^{14}$/M $sec^{-1}$and the activation energy($E_{a}$) was 8.19kcal/mol. While the A value was 1.947x $10^{14}$/M $sec^{-1}$ and the ($E_{a}$ value was about 15~19kcal/mol in NaOH-PET decomposition reaction. The much higher A value of the CaO/EG-PET decomposition reaction means that CaO/EG-PET decomposition reaction will occur in a less selective fashion in comparison to the NaOH-PET decomposition reaction. On the other hand, the lower ($E_{a}$) value of the CaO/EG-PET decomposition reaction than that of the NaOH-PET decomposition reaction means that CaO/EG-PET decomposition reaction is less sensitive on the variation of temperature than NaOH-PET decomposition reaction.

• BMB Reports
• /
• v.39 no.6
• /
• pp.717-721
• /
• 2006

In vitro analyses of type I signal peptidase activities require protein precursors as substrates. Usually, these pre-proteins are expressed in vitro and cleavage of the signal sequence is followed by SDS polyacrylamide gel electrophoresis coupled with autoradiography. Radioactive amino acids have to be incorporated in the expressed protein, since the amount of the in vitro expressed protein is usually very low and processing of the signal peptide cannot be followed by SDS polyacrylamide gel electrophoresis alone. Here we describe a rapid and simple method to express large amounts of a protein precursor in E. coli. We have analyzed the effect of ionophors as well as of azide on the accumulation of expressed protein precursors. Azide blocks the function of SecA and the ionophors dissipate the electrochemical gradient across the cytoplasmic membrane of E. coli. Addition of azide ions resulted in the formation of inclusion bodies, highly enriched with pre-apo-plastocyanine. Plastocyanine is a soluble copper protein, which can be found in the periplasmic space of cyanobacteria as well as in the thylakoid lumen of cyanobacteria and chloroplasts, and the pre-protein contains a cleavable signal sequence at its N-terminus. After purification of cyanobacterial pre-apo-plastocyanine, its signal sequence can be cleaved off by the E. coli signal peptidase, and protein processing was followed on Coomassie stained SDS polyacrylamide gels. We are optimistic that the presented method can be further developed and applied.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.26 no.1
• /
• pp.8-13
• /
• 1990

The microscopic relaxation parameters for the single crystal were measured by using thermally stimulated depolarization (TSD). Initial rise method, various heating rate method and total glow peak method were used for the determination of the activation energy and Debye relaxation time from TSD glow curves. Activation energy, pre-exponential factor and relaxation time for impurity-vacancy dipole reorientation were 0.55eV, 1.97$\times$10 super(-12) sec and 12.19sec in average, respectively. Dielectric dissipation factor for the crystal was calculated from the measured TSD glow curve, its value being about 3$\times$10 super(-2).

• The Journal of Korean Physical Therapy
• /
• v.18 no.5
• /
• pp.43-51
• /
• 2006

Purpose: The purpose of this study was to examine the effects of static stretching and Evjenth-Hamberg stretching on isokinetic muscle strength of knee flexors and extensors. Methods: The subjects were composed of eighty healthy males without weight-training experience. ROM of knee joint measured active maximal extension and isokinetic Peak Torque measured $60^{\circ}/sec,\;120^{\circ}/sec$ using an the En-Knee. Three tests(Baseline, 4 weeks, 8 weeks, respectively) was operated to examine change of each variable. Data were analyzed with a $2{\times}3$ analysis of variance ($group{\times}test$) for repeated measures on last factor by SPSS package 10.0. The data analysis revealed muscle strength were dependent on stretching method. Results: The results were as follows. First, Evjenth-Hamberg stretching(E-HS) was more effective than static stretching(SS) on ROM. Second, Peak Torque of knee flexors and extensors was improved in both methods by each time. but E-HS was more improved than SS. Conclusion: In conclusion, This study indicates that E-HS is more efficient than SS on muscle strength improvement.

• Food Science of Animal Resources
• /
• v.18 no.2
• /
• pp.157-163
• /
• 1998

This study was carried out to examine that pepsin-hydrolyzed bovine lactoferrin has applicabilities which are market milk and dairy products. The stability of pepsin-hydrolyzed bovine apo-lactoferrin and the change of its antibacterial character has been studied under various method for pasteurization (LTLT; 65$^{\circ}C$ / 30min., HTST ; 75$^{\circ}C$ / 15sec., UHT ; 135$^{\circ}C$ / 3sec.) and pH Values (pH 2.0, pH 4.0, pH 6.8). The ehated samples were assayed for minimal bacteriocidal concentrations (MBCs) and bacteriocidal effect against E. coli. The results obtained were summarized as follows: After fractionation of pepsin-hydrolyzed bovine lactofeerin by gel filtration. several peptide fractions were found that had strong antibacterial activity. SDS-PAGE showed that the one of these fractions with strong antibacterial activity, which had a molecular mass a range of 30∼33KDa. The MBCs for pepsin-hydrolyzed bovine lactoferrin fraction No. 2 against E. coli required to cause complete inhibition of growth varied within the range of 200∼400 $\mu\textrm{g}$/ml, depending on heat treatments and pH conditions. The peptide fraction No. 2 showed strong bacteriocidal activity against E. coli at LTLT and HTST treatments under acidic pH conditions. and was reduced activity at UHT treatment under pH 6.8 condition.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.2
• /
• pp.274-282
• /
• 2019

Mercury-resistant ($Hg^R$) bacteria were isolated from heavy metal polluted wastewater and soil collected near to tanneries of district Kasur, Pakistan. Bacterial isolates AZ-1, AZ-2 and AZ-3 showed resistance up to $40{\mu}g/ml$ against mercuric chloride ($HgCl_2$). 16S rDNA ribotyping and phylogenetic analysis were performed for the characterization of selected isolates as Bacillus sp. AZ-1 (KT270477), Bacillus cereus AZ-2 (KT270478) and Bacillus cereus AZ-3 (KT270479). Phylogenetic relationship on the basis of merA nucleotide sequence confirmed 51-100% homology with the corresponding region of the merA gene of already reported mercury-resistant Gram-positive bacteria. The merE gene involved in the transportation of elemental mercury ($Hg^0$) via cell membrane was cloned for the first time into pHLV vector and transformed in overexpressed C43(DE3) E. coli cells. The recombinant plasmid (pHLMerE) was expressed and the native MerE protein was obtained after thrombin cleavage by size exclusion chromatography (SEC). The purification of fusion/recombinant and native protein MerE by Ni-NTA column, dialysis and fast protein liquid chromatography (FPLC/SEC) involved unfolding/refolding techniques. A small-scale reservoir of wastewater containing $30{\mu}g/ml$ of $HgCl_2$ was designed to check the detoxification ability of selected strains. It resulted in 83% detoxification of mercury by B. cereus AZ-2 and B. cereus AZ-3, and 76% detoxification by Bacillus sp. AZ-1 respectively (p < 0.05).