• Microbiology and Biotechnology Letters
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• v.37 no.1
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• pp.17-23
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• 2009

The gene encoding Thermus thermophilus HJ6 DNA polymerase (Tod) was cloned and sequenced. The open reading frame (ORF) of the Tod gene was composed of 2,505 nucleotides and encoded a protein (843 amino acids) with a predicted molecular weight of 93,795 Da. The deduced amino acid sequence of Tod showed 98% and 86% identities to the Thermus thermophilus HB8 DNA pol and Thermus aquaticus DNA pol, respectively, The Tod gene was expressed under the control of the bacteriophage $\lambda$ promoters PR and PL on the expression vector pJLA503 in Escherichia coli strain BL21 (DE3) codon plus. The expressed enzyme was purified by heat treatment, $HiTrap^{TM}$ Q column, and $HiPrep^{TM}$ Sephacryl S-200 HR 26/60 column chromatographies. The optimal temperature and pH for DNA polymerase activity were found to be $75{\sim}80^{\circ}C$ and 9.0, respectively. The optimal concentrations of $Mg^{2+}$ and $Mn^{2+}$ were 2.5 mM and 1 mM, respectively. The enzyme activity was activated by divalent cations, and was inhibited by monovalent cations. The result of the PCR experiment with Tod DNA polymerase indicates that this enzyme might be useful in DNA amplification and PCR-based applications.

• Journal of Animal Science and Technology
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• v.58 no.1
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• pp.2.1-2.10
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• 2016

Background: Heat stress adversely affects the physiological and metabolic status, and the productive performance of buffalo. Methods: The present study was conducted to explicate the effect of misting and wallowing cooling strategies during heat stress in lactating Murrah buffalo. The study was conducted for three months (May-July) of which first two months were hot dry and last month was hot humid. Eighteen lactating buffaloes, offered the same basal diet, were blocked by days in milk, milk yield and parity, and then randomly allocated to three treatments: negative control (no cooling), cooling by misting, and cooling by wallowing. Results: The results showed higher (P < 0.05) milk yield in buffaloes of misting and wallowing group compared to control during the experimental period however wallowing was found more (P < 0.05) effective during July (hot humid period). Both the treatments resulted into significant (P < 0.05) reduction in rectal temperature (RT) and respiratory rate (RR) compared to control animals during study period whereas wallowing was found to be effective on pulse rate (PR) only during July. Both treatments were resulted in mitigating the heat stress mediated decrease in packed cell volume (PCV), lymphocytopnoea and neutrophilia whereas decrease in total erythrocyte count (TEC) and monocytes was only mitigated by wallowing. Heat load induced alteration in serum creatinine and sodium concentration was significantly (P < 0.05) ameliorated by misting and wallowing whereas aspartate aminotransferase, alkaline phosphatase and superoxide dismutase activity, and reactive oxygen species concentration could be normalized neither by misting nor by wallowing. The significant (P < 0.05) increment in serum cortisol and prolactin levels observed in June and July period in control animals was significantly (P < 0.05) prevented by misting and wallowing. Conclusions: It can be concluded that misting and wallowing were equally effective in May and June (hot dry period) whereas wallowing was more effective during hot humid period in preventing a decline in milk production and maintaining physiological, metabolic, endocrine and redox homeostasis.

• Journal of Energy Engineering
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• v.19 no.2
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• pp.73-80
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• 2010

A solid oxide fuel cells(SOFC) is a clean energy technology which directly converts chemical energy to electric energy. When the SOFC is used in cogeneration then the efficiency can reach higher than 80%. Also, it has flexibility in using various fuels like natural gases and bio gases, so it has an advantage over polymer electrolyte membrane fuel cells in terms of fuel selection. A typical cathode material of the SOFC in conjunction with yttria stabilized zirconia(YSZ) electrolyte is still Sr-doped $LaMnO_3$(LSM). Recently, application of mixed electronic and ionic conducting perovskites such as Sr-doped $LaCoO_3$(LSCo), $LaFeO_3$(LSF), and $LaFe_{0.8}Co_{0.2}O_3$(LSCF) has drawn much attention because these materials exhibit lower electrode impedance than LSM. However, chemical reaction occurs at the manufacturing temperature of the cathode when these materials directly contact with YSZ. In addition, thermal expansion coefficient(TEC) mismatch with YSZ is also a significant issue. It is important, therefore, to develop cathode materials with good chemical stability and matched TEC with the SOFC electrolyte, as well as with high electrochemical activity.

• Ecology and Resilient Infrastructure
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• v.4 no.3
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• pp.130-141
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• 2017

We evaluated the field application feasibility that biologically derived substances (Naphthoquinone derivate: NQ 2-0) can be used for the eco-friendly mitigation of natural harmful cyanobacterial blooms in freshwater. We conducted a 30 ton scale mesocosm experiment to investigate the effects of NQ 2-0 on biotic and abiotic factors in water collected from Gi-heung reservoir. In the mesocosm experiments, the abundance of Microcystis sp. was continuously increased in the control. However, the Microcystis sp. cell density was sharply decreased on the $10^{th}$ day. In the treatment, NQ 2-0 showed the strong and selective algicidal activity toward the target cyanobacteria (Microcystis sp.). Accordingly, the algicidal activity of NQ 2-0 compound increased gradually until $10^{th}$, $15^{th}$ days and algal biomass was decreased to 99.4 and 100 %, respectively. NQ 2-0 compound was not only selective algicidal activity but also the growth of other phytoplankton and increased the Shannon-Wiener diversity index of phytoplankton. In the mesocosm experiments, the dynamics of biotic (bacteria, heterotrophic nanoflagellate, ciliates, zooplankton) and abiotic (water temperature, dissolved oxygen, pH, conductivity, nutrients) factors remained unaffected. These results suggest that NQ 2-0 could be a selective and ecologically safe algicide to mitigate harmful cyanobacterial blooms. In addition, it is believed that NQ 2-0 will play a major role in forming a healthy aquatic ecosystem by facilitating habitat and food supply of aquatic organisms.

• Journal of Food Hygiene and Safety
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• v.16 no.1
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• pp.27-32
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• 2001

Antibiotic resistance of thirty strains of Shigella sonnei isolatedfrom patient of Shigellosis outbreke at Young Cheon area in 1998 was tested. Twenty-seven strains were resistant to Tr(Trimethoprim-Sulfamethoxazol) and Shigella sonnei SG-48 was resistant to Tr(Trimethopirm-Sulfamethoxazol), Ap(Ampicillin), Cp(Cephalothin) and Pi(Piperacillin). Shigella sonnei SG-49, SG-66, and SG-73 were senstive to all tested antibiotics. Physiological charactristics of isolated Shigella sonnei SG-48, SG-49, SG-57, and SG-73 such as effect of pH, NaCl concentration and temperature on the growth, survival in adverse condition and heat resistance were investigated Growth of the strains were inhibited at pH 4 and pH 9. All strains were grown in Tryptic soy broth containing 6% of NaCl but inhibited in TSB containing 9% of NaCl except Shigella sonnei SG-73 after incubation for 18hrs at 37$^{\circ}C$. Selected strains grew during storage at 10 but did not grow at 4. The strains were survived in 1% pepton solution for 15 days at 37$^{\circ}C$. Viable cell of selected strains were decreased 45 log cycle after heat treatment for 30 mins at 6$0^{\circ}C$ but did not detect by heat treatment for 5 mins at 7$0^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.806-813
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• 2000

Attempts were made to evaluate possibilities of adding water soluble chitosan to milk for improving functionality of milk, and physico-chemical and sensory properties of chitosan added milk were studied. pH and acidity of milk with ethyl alcohol washed chitosan were close to those of control. Color and consistency of chitosan added milk were better with chitosan of lower molecular weight than with high molecular weight. Chitosan of high molecular weight resulted in increased consistency and browning of milk. Milk with less than 1.0% chitosan could be sterilized at $73^{\circ}C$ for 15 sec. with minimum protein coagulation and increase of consistency. Low molecular weight chitosan$(MW\;0.2{\sim}3\;kDa)$ accelerated the growth of Bifidobacterium bifidum, showing 10 times more cell population after 32 hrs incubation. Sensory tests showed that adding chitosan to the regular city milk resulted in significant difference in color and chemical off-flavor(p<0.05). When chitosan was added to coffee milk, there was no significant difference in sensory quality from control. The storage test showed that pH, acidity, consistency and color of coffee milk with 0.5% chitosan did not change markedly during 30 days storage at 0 and $5^{\circ}C$, but changed rapidly after 16days storage at $10^{\circ}C$. Bacterial counts increased when storage temperature was high, and the growth of bacteria was delayed in coffee milk with chitosan.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.707-717
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• 2018

Leukocytes are reportedly the first line of the innate immune defense and essential for the control of common bacterial infections. Therefore, in this work, the antibacterial activity of crocodile leukocyte extract against Propionibacterium acnes was evaluated, and we also characterized the related activity of skin infection. The leukocyte extract showed the minimum inhibitory concentration to be $100{\mu}g/ml$ to P. acnes. SEM imaging demonstrated that the leukocyte extract adversely affected P. acnes cell permeability in a concentration-dependent manner. Furthermore, the crocodile leukocyte extract could significantly reduce proinflammatory markers and decrease inflammatory signs in infected mouse ears. The crude leukocyte extract was further purified using FPLC and RP-HPLC. The resulting fraction F5 was indicated as the anti-acne peptide-containing fraction. The molecular mass of the peptide contained in F5 was calculated to be 4,790.5 Da. N-Terminal sequencing revealed the amino acid sequence as GPEPVPAIYQ, which displays similarities to immunoglobulin A and leucine-rich repeat neuronal protein. This is the first reported amino acid sequence of a crocodile leukocyte extract that possesses anti-acne activity. To attempt to use it in a prototype cosmetic, an anti-acne gel containing crude crocodile leukocyte extract was formulated, resulting in seven gel formulations (G1, G2, G3, G4, G5, G6, and G7). The formulations G5, G6, and G7 exhibited 2-fold higher anti-acne activity than G1-G4. Investigation of accelerating stability studies of anti-acne gel formulations G5, G6, and G7 demonstrated that a low storage temperature ($4^{\circ}C$) is suitable for maintaining the physical properties and biological activity of the anti-acne gel products.

• Journal of Pharmaceutical Investigation
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• v.35 no.6
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• pp.417-422
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• 2005

This study was aimed to design and formulate the moisture-activated patches containing ofloxacin and lidocaine for antibacterial and local anesthetic action. The solubility of lidocaine at $32^{\circ}C$ in various vehicles decreased in the rank order of PG $759.5{\pm}44.5\;mg/mL$ > PGL > IPM > PEG 300 > PEG 400 > Ethanol > PGMC > DGME > PGML > OA > $Captex^{\circledR}\;300$ > $Captex^{\circledR}\;200$ > water $(4.0{\pm}0.1\;mg/mL)$. Ofloxacin revealed very low solubility, which the highest solubility was obtained from PEG 400 $(18.7{\pm}6.3\;mg/mL)$ among the vehicles used. The addition of lactic acid increased the solubility of ofloxacin dramatically; the solubility at 5% lactic acid was $133.7{\pm}9.7\;mg/mL$. As $2-hydroxypropyl-{\beta}-cyclodextrin$ was added at the concentrations of 40, 80, 120, 160 and 200 mM, the solubilities of lidocaine and ofloxacin were enhanced up to three and two times, respectively, with concentration-dependent pattern. Gel intermediates for filmtype patches were prepared with mucoadhesive polymer, viscosity builders, lidocaine or ofloxacin at pH values from 5 to 7. Gels were cast onto a release liner and dried at room temperature. Dried patch was attached onto an adhesive backing layer, thus forming a patch system. Patches containing a single drug component were characterized by in vitro measurement of drug release rates through a cellulose barrier membrane. The release study was carried out at $37^{\circ}C$ using a Franz-type cell. Receptor solutions were isotonic phosphate buffers (pH 7.4). Samples $(100\;{\mu}L)$ were taken over 24 hours and quantitated by a verified HPLC method. The releases from all tested were proportional to the square root of time. The release rates were 0.9, 157.3 and $281.7\;{\mu}g/cm^{2}/min^{1/2}$ for the lidocaine patches and 19.8,37.2 and $50.7\;{\mu}g/cm^{2}/min^{1/2}$ for the ofloxacin patches at the concentrations of 0.3, 0.5 and 1 %, respectively. The release rates were dose dependent in both drug patches $(R^{2}\;=\;0.9077\;for\;lidocaine;\;R^{2}\;=\;0.9949\;for\;ofloxacin)$ and those were also thickness-dependent $(R^{2}\;=\;0.9246\;for\;lidocaine;\;R^{2}\;=\;0.9512\;for\;ofloxacin)$.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.525-535
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• 2017

In order to produce hydrophilic coating solution, which has superior antifogging and antifouling effect on the glass surface of solar cell module as well as improving photovoltaic efficiency, nanosilica was dispersed in an aqueous solution of Tween 20 and fluorosurfactant composed of decafluorobutane and polyethylene glycol. The antifogging effect at high temperature was excellent for all the coating solutions containing nanosilica, but the antifouling effect was observed when the content of nanosilica was over 6 wt%. As the content of fluorosurfactant increased, the initial water contact angle slightly increased and the antifogging effect remained well until 500 wiping with wet $Wipeol^{(R)}$. The antifouling effect was also excellent regardless of the content of fluorosurfactant, thus 0.1 wt% of the fluorosurfactant was enough for a coating solution production. From the AFM results, when 0.1 wt% to 0.3 wt% of the fluoro surfactant was added, the fractal structure of the coated glass surface was clearly existed and contributed to the better antifouling effect. The transmittance of coated glass surface was highest in TL-1 coating solution containing 0.1 wt% of fluorosurfactant, and the addition of fluorosurfactant in a larger amount than 0.1 wt% did not improve the transmittance. This result is in good agreement with the previous AFM result which shows a high surface roughness as well as a fractal structure formation for the TL-1 coating solution.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.27-33
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• 1979

In early August 1978, a huge red tide occurred off Chilcheon Is, , at the mouth of Jinhae Bay. It expanded rapidly into the central part and then soon covered all the bay except the innermost part of the bay. After staying for a week it disappeared, and thereafter several small scale red tides partially occurred and disappeared untill the end of August. It differed from the red tides hitherto recorded from this bay in respect of the dominant plankter, the geographical extent and the severe damaging effect to local oyster resources. During the red tide period, nevertheless, no oyster damage was found. In September, however, oyster mortailty was found from all rafts and longlines in the bay. Except the inner most part of the bay the oyster farms were completely destroyed. Of the oyster Production in the winter 1978, $96\%$ of an estimated yield of 5,879 tons (shucked meat) was lost and it was estimated to be 2,275 million won, equivalent to $US\$$ 4.55 million. The dominant species was a dinoflagellate, Ceratium fusus and it constituted about $45\%$ of the total phytoplankton. Cell count showed $7.0\times10^4\;cells/\iota$ and chlorophyll-a, $50mg/m^3$ during red tide peak. No oxygen was found ill the bottom waters in September. Sulphides in bottom waters and in the superficial mud increased to 15 and 8-fold respectively in September compared with July ana August. Precipitation from January to May of 1978 was about a third in comparison with the past ten years average but rainfall ill June was two and half-fold more than normal year, and thereafter drought persisited till September Air and water temperatures were also higher, and sunny days continued for a long time without strong winds. Therefore, water was calm for a long time after the red tide extinguished. The result indicated that the occurrence of the Ceratium red tide occurred in that year which was characterized by the combination of the formation of almost anoxic bottom water before the red tide occurrence, high air temperature and the calmness after a great quantity of rainfall in June. The mass mortality of oysters was presumed not to be directly related with the red tide but with the depression of dissolved oxygen in the environmental waters at the bottom due to settling of the red tide organisms.