• Korean Journal of Environmental Biology
• /
• v.37 no.2
• /
• pp.136-143
• /
• 2019

This study investigates the effect of denitrified biofloc water on changes in the water quality parameters and the physiological characteristics of shrimps. Biofloc rearing water contains a large number of microorganisms and can rapidly stabilize the water quality and energy saving if reusable due to high water temperatures. Rearing water contain floating bacteria with both aerobic and anaerobic bacteria. Therefore, when the carbon source is added in limited air supply, the anaerobic state is activated and the denitrification process is possible. In this study, the denitrification water had the following properties: ammonia (6.9 mg L^-1), nitrite (0.3 mg L^-1), nitrate concentration (9.2 mg L^-1), high pH (8.42) and alkalinity (590 mg L^-1). The experimental group consisted of seawater (SW, control), a mixture of Seawater and denitrified biofloc water (DNW) in the ratio of 3:1, 1:1 and DNW only. All experiments were done in triplicate. As a result, the survival rate never changed even when 100% of the denitrification water was utilized. However, a body fluid analysis showed that creatine and BUN were increased due to index of stress and the tissue damage resulting from the high denitrified water content. Body fluid ions (Na⁺, K⁺, and Cl^-) significantly decreased as the denitrified water content increased. It was recommended that the denitrification water be mixed with a certain ratio (less than 50%) in the future as it may affect the osmotic pressure control in shrimps.

• The Plant Pathology Journal
• /
• v.24 no.3
• /
• pp.296-304
• /
• 2008

The transient and rapid expression system of a foreign protein in planta is a very useful technique in biotechnology application. We have investigated optimum condition of Agrobacterium-infiltration technique in which expression level of foreign proteins were maximized without detrimental effects on plants using GFP and Cucumber mosaic virus 2b protein, which is known as an enhancer of gene expression and a suppressor of post-transcriptional gene silencing(PTGS). The optimum expression level of both RNA and protein of GFP with minimum leaf impairment was obtained at $OD_{600}$=0.2 of Agrobactrium inocula. The steady-state levels of GFP RNA and protein generally peaked at 3 and 7 days post-infiltration(dpi), respectively. In the presence of 2b, both the magnitude and duration of GFP expression was highly increased and we could detect GFP level until 17 dpi. On the other hands, the 2b-mediated higher accumulation of foreign proteins resulted in the repression of normal leaf growth, possibly due to the limitation of supply of energy or materials required for growth maintenance. Using this Agrobacterium-infiltration system with 2b and GFP, we tested a hypothesis for the threshold model of PTGS initiation. Four GFP transgenic lines of N. benthamiana, which shows different expression level of GFP were tested to determine the threshold level for PTGS initiation. Agrobacterium-infiltration of GFP into those GFP-transgenic plants resulted in the co-silencing of the transgenic GFP. It was found that very low concentration of Agrobacterium with GFP and GFP+2b($OD_{600}$=0.002-0.02) which could not phenotypically induce an additive GFP expression, was enough to trigger PTGS pathway in all GFP transgenic plants. This strongly indicates that each GFP-transgenic plant should be expressing the transgenic GFP at its own pre-determined level and there was no buffer zone of additive GFP-expression to the threshold. In other words, the PTGS seems to be immediately activated as a self-defensive mechanism if an internal balance of gene expression is broken.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.12
• /
• pp.1695-1701
• /
• 2002

The purposes of this study were to optimize the in vitro maturation (IVM) and culture (IVC) systems of rabbit oocytes. Cytoskeletal structures in the germinal vesicle stage (GV) and during IVM are also investigated. Ovaries were transported from local slaughterhouses and the cumulus-oocyte complexes (COCs) were collected from ovarian follicles (${\geq}1mm$). COCs were randomly allocated to TCM199-based medium ($T_1$, TCM-199) supplemented with $NaHCO_3$, glucose, sodium pyruvate and FSH ($T_2$), $T_2+E_2+LH$ ($T_3$), $T_3+FBS$ ($T_4$), or $T_1+E_2+LH+FSH+FBS$ ($T_5$), for IVM. In Experiment 1, COCs were retrieved from the follicles and 51 GV oocytes were fixed in the fixative (MTSB-XF) for nuclear and cytoplasmic examinations. In Experiment 2, progressive changes of both the nucleus and the cytoskeleton were examined at 0, 6, 16, and 20 h after IVM. Maturation (MR) and developmental rates were assessed in Experiment 3. Cytoplasmic microtubules (MT) were clearly observed in rabbit GV oocytes. To our knowledge, this is the first report that describes the appearance of MT structures in the GV stage ooplasm. Tremendous variations in cytoskeletal alterations were observed among treatments with the exception of the vitelline ring (VR), which is constantly visible and unchanged during maturation. Germinal vesicle breakdown (GVBD) does not occur at 6 h after onset of maturation culture. When the oocytes for IVM were collected within 2 h, results from Experiment 3 showed that rates of nuclear maturation were 42, 8, 42, 37 and 65% at 16 h of IVM for $T_1$ through $T_5$, respectively, in which $T_1$, $T_4$ and $T_5$ had significantly greater MR than those in other groups (p<0.05). Morula/blastocyst development after parthenogenetic activation ranged from 20 to 63% with significantly greater rates in $T_3$, $T_4$ and $T_5$ (p<0.05). These results suggested that oocytes recovered from slaughterhouse ovaries can be matured and parthenogenetically activated in vitro, but the MR remained low in this study. Addition of $E_2$ and LH in the medium may be beneficial for cytoplasmic maturation, but FBS exerts a nega- tive role in the subsequent development of parthenogenetic embryos when energy substrates are provided in the IVC media. More studies are required for improving the MR and further development of the GV stage rabbit oocytes.

• Journal of the Korean Applied Science and Technology
• /
• v.16 no.3
• /
• pp.263-271
• /
• 1999

We checked the presence of phospholipase $A_2(PLA)_2$ which could split the ester bond at the position 2 in the glycerol backbone of glycerophospholipids, in the cells of hyperthermophiles of Pyrococcus horikoshii and Sulfolobus acidocaldarius. The results obtained are as follows; (1). Pyrococcus horikoshii cells were grown in obligate anaerobic conditions at $95^{\circ}C$ and they needed sulfur as energy source instead of oxygen, while Sulfolobus acidocaldarius species grew well in the aerobic medium (pH 2.5) containing yeast and sucrose at $75^{\circ}C$. (2). Pyrococcus horikoshii cells produced phospholipase $A_2$ in the cell culture media although this species did not show lipase activity at least in the pH range of 1.5 ${\sim}$ 3.5. Sulfolobus acidocaldarius cells produced lipase hydrolyzing triacylglycerols such as triolein, but did not split any kind of phospholipids used as substates. (3). The compound of 1-decanoyl-2-(p-nitrophenylglutaryl) phosphatidylcholine was not suitable for a substrate in this experiment, though frequently used as a subtrate for checking presence of phospholipase $A_2$, for its decomposi-tion in this experiment. The L-${\alpha}$-phosphatidylcholine-${\beta}$-[N-7-nitrobenz-2-oxa-1, 3-diazol]aminohexanoyl-${\gamma}$-hexadecanoyl labelled with a fluorescent material, did not show any migration of acyl chains in the molecule during the reaction with phospholipase $A_2$ under a hot condition. (4). Phospholipase $A_2$ in the cells of Pyrococcus horikoshii, showed the optimum activity at $pH6.7{\sim}7.2$ and $95{\sim}105^{\circ}C$, respectively, and was activated by addition of calcium chloride solution. Andthe phospholipase $A_2$ specifically hydrolyzed glycero-phospholipids such as phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl serine and phosphatidyl inositol, but could not split phospholipid containing ether bonds in the molecule such as DL -${\alpha}$-phosphatidylcholine-${\beta}$-palmitoyl-${\gamma}$-O-hexadecyl, DL-${\alpha}$-phosphati- dylcholine-${\beta}$- oleoyl-${\gamma}$-O-hexadecyl, DL-phosphatidylcholine-dihexadecyl.

• Microbiology and Biotechnology Letters
• /
• v.16 no.4
• /
• pp.310-315
• /
• 1988

Two isoenzymes of chorismate mutase(E.C.5.4.99.5) designated as chorismate mutase I(CM I) and chorismate mutase II(CM II), were detected and partially purified from a sp. of intrasporangium isolated from soil. CM I and CM II had pH optima of pH 6.5 and 8.0, respectively and showed the same temperature optimum of 45$^{\circ}C$. The activation energy of the enzymatic reaction was estimated to be 14.7kcal/ mole with CM I and 10.8kcal/mole with CM II. The affinity of isoenzyme CM I for substrate(Km= 1.35mM) was almost the same level as that of CM II(Km = 1.22mM). Both isoenzymes were stable at pH values ranged from pH 6.5 to 9.0, but rapidly denaturated at temperatures above 45$^{\circ}C$. CM II was activated about 7$^{\circ}C$ of its activity by $Ba^{++}$ or $Mg^{++}$ while CM I was slightly inhibited by the same metal ions. Thiol compounds were found not to be necessary for stability of the two enzymes but Co$^{++}$ and EDTA had a little stabilizing effect on CM II only. p-Chloromercuribenzoate strongly inactivated the activities of both enzymes but the reducing agents such as dithiothreitol and L-cysteine protected them against the pCMB inhibition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.10a
• /
• pp.170-174
• /
• 2007

Although research efforts for brain waves have prospered in medicine and engineering, acupuncture still has a long way to go regarding researches on brain waves analysis. Thus this study set out to analyze brain waves stimulated by indirect mugwort moxibustion, which was part of acupuncture techniques, and to investigate their correlations with the automatic nervous system. For the experiments, stimulation was given to Jungwan, Shingwol and Gwanwon, which were some of the spots on the body suitable for acupuncture, through indirect mugwort moxibustion. The subjects' brain waves were measured before the stimulation, during the stimulation, and one hour and two hours after the stimulation. The measurements were analyzed with Matlab 7.0 for FFT and frequency power spectrum. Then the ${\alpha}$, ${\beta}$, ${\delta}$, and ${\theta}$ waves were analyzed and examined for changes to the percentage of each frequency and to the amplitude of vibration according to the stages of stimulation. The EEG data of the entire brain were translated into FFT to analyze the percentage of the ${\alpha}$, ${\beta}$, ${\delta}$, and ${\theta}$ waves. As a result, the ${\alpha}$ waves recorded a double increase after the stimulation. The power spectrum analysis results of the entire brain decreased the ${\alpha}$ and ${\beta}$ waves dropping in the energy level, which suggested that the parasympathetic nerves were activated. When the results of the study were compared with those of the previous study, it's confirmed that indirect moxibustion stimulation could cause changes to the automatic nervous system and bring stability to those who were nervous or under stress due to the proportionate increase of the ${\alpha}$ waves.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.297-297
• /
• 2010

Precise control of the position and density of doping elements at the nanoscale is becoming a central issue for realizing state-of-the-art silicon-based optoelectronic devices. As dimensions are scaled down to take benefits from the quantum confinement effect, however, the presence of interfaces and the nature of materials adjacent to silicon turn out to be important and govern the physical properties. Utilization of visible light is a promising method to overcome the efficiency limit of the crystalline Si solar cells. Si quantum dots (QDs) have been proposed as an emission source of visible light, which is based on the quantum confinement effect. Light emission in the visible wavelength has been reported by controlling the size and density of Si QDs embedded within various types of insulating matrix. For the realization of all-Si QD solar cells with homojunctions, it is prerequisite not only to optimize the impurity doping for both p- and n-type Si QDs, but also to construct p-n homojunctions between them. In this study, XPS and SIMS were used for the development of p-type and n-type Si quantum dot solar cells. The stoichiometry of SiOx layers were controlled by in-situ XPS analysis and the concentration of B and P by SIMS for the activated doping in Si nano structures. Especially, it has been experimentally evidenced that boron atoms in silicon nanostructures confined in SiO2 matrix can segregate into the Si/$SiO_2$ interfaces and the Si bulk forming a distinct bimodal spatial distribution. By performing quantitative analysis and theoretical modelling, it has been found that boron incorporated into the four-fold Si crystal lattice can have electrical activity. Based on these findings, p-type Si quantum dot solar cell with the energy-conversion efficiency of 10.2% was realized from a [B-doped $SiO_{1.2}$(2 nm)/$SiO_2(2\;nm)]^{25}$ superlattice film with a B doping level of $4.0{\times}10^{20}\;atoms/cm^2$.

• Journal of Life Science
• /
• v.24 no.12
• /
• pp.1356-1363
• /
• 2014

Ghrelin is a 28 amino acid orexigenic peptide hormone that is secreted predominantly by tX/A cells in the stomach, and it plays a major role in energy homeostasis. Activated ghrelin has an n-octanoyl group covalently linked to the hydroxyl group of the Ser3 residue, which is critical for its binding to the G-protein coupled growth hormone secretagogue receptor-1a (GHS-R1a). According to recent reports, both ghrelin and its receptor, GHS-R1a, are expressed by a variety of immune cells, including T- and B-lymphocytes, monocytes, and dendritic cells, and ghrelin stimulation of leukocytes provides a potent immunomodulatory signal controlling systemic and age-associated inflammation and thymic involution. Here, we report that ghrelin protected murine thymocytes from dexamethasone (DEX)-induced cell death both in vivo and in vitro. Subsequently, we explored the molecular mechanisms of the antiapoptotic effect of ghrelin. According to our experiments, ghrelin inhibited the expression of proapoptotic proteins via the regulation of glucocorticoid receptor (GR) phosphorylation. As a result, ghrelin inhibited the proapoptotic activation of proteins, such as Caspase-3, PARP, and Bim. These data suggest that ghrelin, through GHS-R, inhibits the pathway to apoptosis by regulation of the proapoptotic protein activation signal pathway. They provide evidence that blocking apoptosis is an essential function of ghrelin during the development of thymocytes.

• Journal of Life Science
• /
• v.28 no.10
• /
• pp.1140-1146
• /
• 2018

Dual-specificity phosphatases (DUSPs) play a role in cell growth and differentiation by modulating mitogen-activated protein kinases. DUSPs are considered targets for drugs against cancers, diabetes, immune diseases, and neuronal diseases. Part of the DUSP family, DUSP19 modulates c-Jun N-terminal kinase activity and is involved in osteoarthritis pathogenesis. Here, we report screening of cavity-creating mutants and the crystal structure of a cavity-creating L75A mutant of DUSP19 which has significantly enhanced enzyme activity in comparison to the wild-type protein. The crystal structure reveals a well-formed cavity due to the absent Leu75 side chain and a rotation of the active site-bound sulfate ion. Despite the cavity creation, residues surrounding the cavity did not rearrange significantly. Instead, a tightened hydrophobic interaction by a remote tryptophan residue was observed, indicating that the protein folding of the L75A mutant is stabilized by global folding energy minimization, not by local rearrangements in the cavity region. Conformation of the rotated active site sulfate ion resembles that of the phosphor-tyrosine substrate, indicating that cavity creation induces an optimal active site conformation. The activity enhancement by an internal cavity and its structural information provide insight on allosteric modulation of DUSP19 activity and development of therapeutics.

• Journal of Korea Technology Innovation Society
• /
• v.21 no.2
• /
• pp.587-614
• /
• 2018

The Korean government is aiming to strengthen industrial and national competitiveness through the promotion of cooperation between universities, public research institutes and industry and vitalization of technology transfer. In 2013 and 2014, the Ministry of Trade, Industry and Energy and Ministry of Science, ICT and Future Planning have announced policies to support SMEs by public research organizations. In addition, in 2015, the 'Korean Fraunhofer support system', which pay government subsidies according to the amounts of private R&D funds was adopted. However, there are some concern about the government's policies. There is yet disclosed how these policies affect technology transfer because industrial R&D funding has not been activated in Korea unlike German. Therefore this paper analyzes effects of relationship between universities, public research institutes and external organizations on performance of technology transfer based on the Triple Helix Model. Empirical results show that the relationship with the government has a significant impact on the resource security and the relationship with the industry has a significant effect on the diffusion of the performance. In addition, a public research institute was selected and case analysis was conducted to suggest policy implications for improving the technology transfer performance of universities and public research institutes.