• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.547-559
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• 2007

Bacillus thuringiensis (Bt) was first described by Berliner [10] when he isolated a Bacillus species from the Mediterranean flour moth, Anagasta kuehniella, and named it after the province Thuringia in Germany where the infected moth was found. Although this was the first description under the name B. thuringiensis, it was not the first isolation. In 1901, a Japanese biologist, Ishiwata Shigetane, discovered a previously undescribed bacterium as the causative agent of a disease afflicting silkworms. Bt was originally considered a risk for silkworm rearing but it has become the heart of microbial insect control. The earliest commercial production began in France in 1938, under the name Sporeine [72]. A resurgence of interest in Bt has been attributed to Edward Steinhaus [105], who obtained a culture in 1942 and attracted attention to the potential of Bt through his subsequent studies. In 1956, T. Angus [3] demonstrated that the crystalline protein inclusions formed in the course of sporulation were responsible for the insecticidal action of Bt. By the early 1980's, Gonzalez et al. [48] revealed that the genes coding for crystal proteins were localized on transmissible plasmids, using a plasmid curing technique, and Schnepf and Whiteley [103] first cloned and characterized the genes coding for crystal proteins that had toxicity to larvae of the tobacco hornworm, from plasmid DNA of Bt subsp. kurstaki HD-1. This first cloning was followed quickly by the cloning of many other cry genes and eventually led to the development of Bt transgenic plants. In the 1980s, several scientists successively demonstrated that plants can be genetically engineered, and finally, Bt cotton reached the market in 1996 [104].

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.465-465
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• 2009

Wind power is one of the most reliable renewable energy sources and the installed wind turbine capacities are increasing radically every year. Although wind power has been favored by the public in general, the problem with the impact of wind turbine noise on people living in the vicinity of the turbines has been increased. Low noise wind turbine design is becoming more important as noise is spreading more adverse effect of wind turbine to public. This paper demonstrates the design of 10 kW class wind turbines, each of three blades, a rotor diameter 6.4m, a rated rotating speed 200 rpm and a rated wind speed 10 m/s. The optimized airfoil is dedicated for the 75% spanwise position because the dominant source of a wind turbine blade has been known as trailing edge noise from the outer 25% of the blade. Numerical computations are performed for incompressible flow and for Mach number at 0.145 and for Reynolds numbers at $1.02{\times}10^6$ with a lift performance, which is resistant to surface contamination and turbulence intensity. The objective in the low design process is to reduce noise emission, while sustaining high aerodynamic efficiency. Dominant broadband noise sources are predicted by semi-empirical formulas composed of the groundwork by Brooks et al. and Lowson associated with typical wind turbine operation conditions. During the airfoil redesign process, the aerodynamic performance is analyzed to minimize the wind turbine power loss. The results obtained from the design process show that the design method is capable of designing airfoils with reduced noise using a commercial 10 kW class wind turbine blade airfoil as a basis. The new optimized airfoil clearly indicates reduction of total SPL about 3 dB and higher aerodynamic performance.

• Korean Journal of Pharmacognosy
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• v.1 no.3
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• pp.81-92
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• 1970

So far, the cultivated peony is known to be originated from an indigenous species, Paeonia albiflora $P_{ALLAS}$ var. trichocarpa $B_{UNGE}$ (PAT). In this study, these two species were morphologically examined in the external and internal feature and in the pattern of callus formation by tissue culture. Also, they were compared with another indigenous species, P. japonica $M_{IYABE}$ et $T_{AKEDA}$ var. pilosa $N_{AKAI}$ (PJ), which were regarded as being scarcely related to them. The root of the cultivated peony is massive consisting with several storage roots, each of them is a hypotrophic and fusiform. The root of PAT consists of several storage roots, each of them is branching and slender. And the storage root of PJ is short, bended buried horizontally, protruding a number of corpulent lateral root. The secondary xylem of the cultivated peony is small clusters of vessels and xylem fibres are arranged in scalariform and among these cluster, single vessel is joined, but that of PAT is small clusters of vessels are arranged in separate scalariform but are not connected with each other and that of PJ is vessels and xylem fibers are grouped together in elongated clusters that radiate outward from the center. Protoxylem of the cultivated peony is surrounded by four large metaxylem, but that of PAT and PJ by seven. On the other hand, the callus formation patterns of these peonies were different; the cultivated peony callus is formed in an orderly fashion by the mammalate meristematic cell groups, PAT callus is in disorder by the meristematic cells arranged in linear, and PJ callus is in order by the meristematic cells arranged in linear. By the comparison of three different plants in the anatomical appearance and the callus formation pattern, it is evident that the cultivated peony is not derived from PAT.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.330-336
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• 2005

Lactococcus lactis A164 is a nisin Z-producing strain isolated from kimchi. Its antimicrobial spectrum has been found to be active against most Gram-positive bacteria tested, yet inactive against Gram-negative bacteria [3]. Accordingly, to overcome this drawback, the current study attempted to express human $\beta$-defensin-l (hBD-l), which kills both Gram-positive and Gram-negative bacteria in L. lactis AI64. When the hBD-l cDNA was introduced using a nisin Z-controlled expression cassette, the L. lactis A164 transformants grew very poorly, due to the bactericidal effect of the expressed hBD-l against the transformants. Therefore, a gene fusion system was designed to reduce the toxicity of the expressed heterologous protein against the host cells. As such, the hBD-l gene was fused to the DsbC- Tag of pET -40b(+), then introduced to L. lactis A 164. The transformants expressed an intracellular 35.6-kDa DsbC-hBD-l fusion protein that exhibited slight activity against the host cells, yet not enough to strongly inhibit the cell growth. To obtain the recombinant hBD-l, the DsbC-hBD-l fusion protein was purified by nickel-affinity column chromatography, and the DsbC-Tag removed by cleaving with enterokinase. The cleaved mature hBD-l exhibited strong bactericidal activity against E. coli JM109, indicating that the recombinant L. lactis A 164 produced a biologically active hBD-I. In addition, the recombinant L. lactis A 164 was also found to produce the same level of nisin Z as the wild-type.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.525-531
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• 2005

From a genomic library of Lactobacillus reuteri ATCC 55739, one clone, NE347, carrying a pyrH gene encoding UMP kinase, was identified. pNE347 carried a 1.88 kb EcoRI fragment and the pyrH was located in the middle of the insert. pyrH ORF was 723 bp in size and capable of encoding UMP kinase composed of 240 amino acid residues. tsf encoding an elongation factor-Ts and frr encoding a ribosomal recycling factor were present upstream and downstream of pyrH, respectively. When introduced into E. coli KUR1244, a pyrH-negative strain, pNE347 restored the ability to grow at $42^{\circ}C$, indicating that pyrH from L. reuteri synthesized functional UMP kinase in E. coli. Northern blot experiment showed that pyrH and frr were cotranscribed as a 1.4 kb single transcript. pyrH was overexpressed in E. coli by using a pET26b(+) vector, and a major 25 kDa protein band appeared on SDS-polyacrylamide gel.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.3
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• pp.279-285
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• 1995

Despite the frequent incidence of embryo fragmentation in early human embryos, the reason of the embryo fragmentation has not been known yet. This study was conducted to investigate the histological difference(s) between fragmented (FR) and non-fragmented (NFR) human embryos focusing on comparison of mitochondrial distribution and protein synthesis. Multi-pronuclei zygotes (MPZ) such as three or more pronuclei containing in human in vitro fertilization and embryo transfer (IVF-ET) program were used for this study. MPZ were cultured in TCM-199 supplemented with 10% of human fetal cord serum (hFCS) in 5% $CO_2$ incubator at $37^{\circ}C$ for 24 hours. The cleaved embryos to 2-4 cells after 24 hours were grouped by their grade of fragmentation. Embryos were stained with Rhodamine123 (Rh123) and fluorescence was evaluated under the fluorescence microscope through PB 450-490 filter (Leitz). Regarding to protein synthesis during early human embryogenesis, there is no significant difference in the amount of synthetic proteins between FR and NFR embryos. Distribution of cytoplasmic organelles in embryos was evaluated by transmission electron microscope (TEM). The cytoplasmic distribution of mitochondria was different between FR and NFR embryos. The mitochondrial distribution was even in NFR, whereas severely aggregated in FR. It is not able to clarify in the present study whether this uneven mitochondrial distribution in FR embryo is the reason for embryo fragmentation or is the result from fragmentation. Physiological disparity related to the mitochondrial distribution may be one of the reasons for embryo fragmentation. Further studies should be addressed to investigate the physiological differences between FR and NFR embryos.

• Bulletin of the Society of Naval Architects of Korea
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• v.13 no.1
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• pp.1-9
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• 1976

Using the computer programs for calculation of natural vibrations of ship's hull developed by the authors et al., an investigation into influences of various parameters on the accuracy of calculation was done through example calculations of a 30,000 DWT petroleum products carrier M/S Sweet Brier built by Korea Shipbuilding and Engineering Corporation. The methodical principles employed for the computer program development are as follows; (a) the ship system is reduced to an equivalent discrete elements system conforming to Myklestad-Prohl model, (b) the problem formulation is of transfer matrix method, and (c) to obtain solutions an extended $G\ddot{u}mbel's$ initial value method is introduced. The scope of the investigation is influences of number of discrete elements, choice of significant system parameters such as rotary inertia, bending stiffness and shear stiffness, and simplification of distributions of added mass and stiffness as trapezoidal ones referred to those of midship section on the calculation accuracy. From the investigation the followings are found out; (1) To obtain good results for the modes up to the seven-noded thirty or more divisions of the hull is desirable. For fundamental mode fifteen divisions may give fairly good results. (2) The influence of rotary inertia is negligibly small at least for the modes up to the 5- or 6- noded. (3) In the case of assuming either bending modes or shear modes the calculation results in considerably higher frequencies as compared with those based on Timoshenko beam theory. However, the calculation base on the slender beam theory surprisingly gives frequencies within 10% error for fundamental modes. (4) It is proved that to simplify distributions of added mass and stiffness as trapezoidal ones referred to those of midship section is a promising approach for the prediction of natural frequencies at preliminary design stage; provided good accumulation of data from similar type ships, we may expect to obtain natural frequencies within 5% error.

• Journal of Ocean Engineering and Technology
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• v.29 no.6
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• pp.445-453
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• 2015

The stress triaxiality and lode angle are known to be most dominant fracture parameters in ductile materials. This paper proposes a three-dimensional failure strain surface for a ductile steel, called a low-temperature high-tensile steel (EH36), using average stress triaxiality and average normalized lode parameter, along with briefly introducing their theoretical background. It is an extension of previous works by Choung et al. (2011; 2012; 2014a; 2014b) and Choung and Nam (2013), in which a two-dimensional failure strain locus was presented. A series of tests for specially designed specimens that were expected to fail in the shear mode, shear-tension mode, and compression mode was conducted to develop a three-dimensional fracture surface covering wide ranges for the two parameters. This paper discusses the test procedures for three different tests in detail. The tensile force versus stroke data are presented as the results of these tests and will be used for the verification of numerical simulations and fracture identifications in Part II.

• Korean Journal of Medicinal Crop Science
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• v.15 no.6
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• pp.434-436
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• 2007

In the previous study, we reported the inhibitory effects of Rodgersia podophylla root extract on tyrosinase activity and melanin production in melan-a cells. However, mechanism of the inhibitory activity and in vivo assay were not yet examined. This study performed the examination of the effects of Rodgersia podophylla root extract on protein expression and in vivo depigmenting activity using melan-a cells and brown guinea pigs. As the results of western immunoblotting analysis, treatment of Rodgersia podophylla root extract reduced tyrosinase expression rates in 10 and 100 ppm concentrations, dose dependently. Moreover, Rodgersia podophylla root extract exhibited depigmenting activity on UV-B induced hyperpigmentation in brown guinea pig skin. These results suggested that Rodgersia podophylla root extract could act as whitening agent for the skin via not only direct tyrosinase activity inhibition but also reducing of tyrosinase expression.

• The Korean Journal of Nuclear Medicine
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• v.34 no.5
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• pp.436-437
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• 2000

A 63-year-old male who had subtotal gastrectomy for early gastric cancer three months ago underwent Tc-99m bone scintigraphy for the evaluation of skeletal metastases. He had no symptoms such as fever, tenderness, or wound discharge. On physical examination, the surgical scat along the midline of the upper abdomen had keloid formation and there was no radiographic evidence of calcification. Bone scintigraphy (Fig. 1A & 1B) demonstrated all unusual linear increased uptake along the midline of the upper abdomen that corresponded to the,skin incision for subtotal gastrectomy. Usually, an incisional scar will not be visualized in Tc-99m methylene diphosphate (MDP) scintigraphy beyond two weeks after surgery.$^{1)}$ Upon reviewing the literature, there were only a few reports where localization of Tc-99m MDP in surgical scars were found two months after surgery.$^{2)}$ It was also reported that a few cases with Tc-99m MDP uptake in the keloid scar developed after surgery. Although there are several potential mechanisms that may explain the uptake of Tc-99m MDP in scar tissue, the primary mechanism in older scars is suggested to be a result of pathological calcification.$^{2)}$ Siddiqui et al$^{3)}$ suggested it could be due to microscopic calcification in small resolving hematomas. However, the primary mechanism in keloid scar is not well-known. We should obtain oblique or lateral views to differentiate the uptake in healing surgical scars from the artifactual uptake.