• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.504-507
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• 2005

Trichoderma reesei KCTC 6952 possesses cellulase system consisting of three enzymatic components necessary to synergistically hydrolyze crystalline cellulose, among which ${\beta}$-glucosidase effectively releases glucose from glycoside derivatives. ${\beta}$-Glucosidase of T. reesei KCTC 6952 grown in modified Mandels' medium showed maximum activity(1.33 unit/mL) 4 days after initiation of growth. Optimal reaction conditions of the enzyme were 50 mM sodium acetate (pH 5) at $70^{\circ}C$ for 10 min. Enzymatic activities stabilized below $50^{\circ}C$ at pH range of 4-5. Results show ${\beta}$-glucosidase exerted its catalytic activities at relatively high temperatures and broad pH range.

• Journal of Mushroom
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• v.13 no.2
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• pp.145-150
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• 2015

Mushroom sciarid fly Lycoriella ingenua (Dufour), syn. L. mali (Fitch) is one of the most common fly pests affecting the mushroom cultivation in Korea. This study was carried out to investigate the development at different temperatures and damages of L. ingenua in A. bisporus mushroom cultivation. Rearing of mushroom flies were carried out on mycelial culture in Petri dishes. The development of L. ingenua from egg to adult at the temperature of 16, 20, 24, $28^{\circ}C$ were 35.2, 25.8, 23.5, and 22.2 days, respectively. Adult flies invade mushroom farms and oviposit in freshly spawned compost. Damages are mainly caused by the larvae of 1-7 mm, which feed on growing mycelium and also developing stipes and caps of mushrooms. Adult flies spoil the appearance of the fruiting bodies, spread various fungal and bacterial disease, and transmit mites. The damages by mushroom flies increased without pest control causing yield loss of up to 27%.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1217-1226
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• 2004

A psychrotrophic bacterial strain, Pseudomonas fluorescens BM07, synthesized unsaturated fatty acids (UFA) from fructose in response to lowering of growth temperature, and incorporated them into both polyhydroxyalkanoic acid (PHA) and membrane lipid. The blocking of PHA synthesis by adding 5 mM 2-bromooctanoic acid to the growth medium, containing 70 mM fructose, was found to be a useful means to profile the composition of membrane lipid by gas chromatography. As the growth temperature changed from 35 to $50^{\circ}C$, the total content of two UFA, 3-hydroxy-cis-5­dodecenoic acid ($C_{12:1}$) and 3-hydroxy-cis-7-tetradecenoic acid ($C_{14:1}$), in PHA increased from 31 to 44 $mol\%$. The growth at lower temperatures also led to an increase in the level of two major UFA, palmitoleic acid (C16:1 cis9) and cis-vaccenic acid (C18:1 cis11), in membrane lipid. A fraction of these membrane-lipid UFA was converted to their corresponding cyclopropane fatty acids (CFA). The CFA conversion was a function of culture time, exhibiting biphasic increase before and after entering the stationary phase. However, pH changes in growth media had no effect on the CFA conversion, which is contrary to the case of E. coli reported. The cells grown at $30^{\circ}C$ responded to a cold shock (lowering the medium temperature down to $10^{\circ}C$) by increasing the level of C16:1 cis9 and C 18: I cis II up to that of $10^{\circ}C$-grown control cells and concomitantly decreasing the relative level of cis-9,10­methylenehexadecanoic acid (the CFA converted from C16:1 cis9) from 14 to 8 $mol\%$, whereas the 10-grown cells exhibited little change in the lipid composition when exposed to a warmer environment of $30^{\circ}C$ for 12 h. Based on this one- way response, we suggest that this psychrotrophic strain responds more efficiently and sensitively to a cold shock than to a hot shock. It is also suggested that BM07 strain is a good producer of two unsaturated 3-hydroxyacids, $C_{12:1}\;and\;C_{141:1}$.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.353-360
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• 2003

For the simple rapid bioassay of organophosphorus and carbamate pesticide residues, a mass-production system of acetycholinesterase (AChE, EC 3.1.1.7, MAChE) using baculovirus and insect cell culture was constructed. The cDNA for AChE was synthesized from Drosophila melanogaster in Halla Mountain, the lipid anchor tail was removed by PCR and was used for the site-directed mutagenesis of three amino acid residues (E107Y, F368L, L408F). The mutated cDNA was inserted into the baculovirus vector and expressed in insect cells. Maximum cell growth and enzyme activity were reached when the cells $(2{\times}10^6\;cell/ml)$ were infected four times at four-day-intervals. His-tag containing MAChE was purified using Ni-NTA column and used for characterization. The activity was maintained under various pHs (3-10) and temperatures $(20-50^{\circ}C)$ under experimental conditions. As an extraction solution for pesticides, methanol is more effective than ethanol. Against major organophosphate and carbamate pesticides, the MAChE showed better sensitivity than AChE and AChE from housefly (Taiwan).

• Fisheries and Aquatic Sciences
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• v.23 no.1
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• pp.1.1-1.14
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• 2020

Background: Dietary protein requirements are dependent on a variety of factors and water temperature is one of the most important abiotic factors affecting protein requirement of fish. This study was, therefore, conducted to investigate effects of water temperature on dietary protein requirement of fry Heteropneustes fossilis which has high demand in most of the Asian markets. Methods: Quadruplicate groups of 30 fish per treatment (2.97 ± 0.65 cm; 5.11 ± 0.34 g) were fed seven isoenergetic diets (17.9 kJ g^-1 gross energy; 14.99 kJ g^-1 digestible energy) containing dietary protein levels ranging from 28 to 52% at two water temperatures (18 and 26 ℃). Experimental diets were fed to apparent satiation as semi-moist cakes thrice daily at 17:00, 12:00, and 17:30 h for 12 weeks. For precise information, various growth parameters, protein deposition, hematological parameters, metabolic enzymes, and stress response were analyzed, and effects of water temperature on dietary protein requirement was recommended on the basis of response from above parameters. Results: Groups held at 26 ℃ attained best growth, feed conversion, and protein deposition at 44% dietary protein indicating that temperature affected dietary protein requirement for optimum growth of H. fossilis fry and protein requirement seems to be satisfied with 44% dietary protein. Interestingly, interactive effects of both dietary protein levels and temperature were not found (P > 0.05). Fish reared at 18 ℃ had comparatively higher values for aspartate and alanine transferases than those reared at 26 ℃ water temperature which exhibited normal physiological value for these enzymes indicating that body metabolism was normal at this temperature. Hematological parameters also followed same pattern. Furthermore, fish reared at 26 ℃ water temperature exhibited more resistant to thermal stress (P < 0.05). The 95% maximum plateau of protein deposition data using second-degree polynomial regression analyses exhibited dietary protein requirement of fry H. fossilis between 40.8 and 41.8% of diet at 26 ℃ water temperature. The recommended range of dietary protein level and protein/digestible energy ratio for fry H. fossilis is 40.8-41.8% and 27.21-27.88 mg protein kJ^-1 digestible energy, respectively. Conclusions: Information developed is of high significance for optimizing growth potential by making better utilization of nutrient at 26 ℃ and, to develop effective management strategies for mass culture of this highly preferred fish species.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.319-324
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• 2012

Production of liquid starters using wheat bran as a medium for Rhizopus oryzae N174 and the changes in their characteristics noted during storage were investigated in this study. The optimal culture conditions of the liquid starters were determined to be 5~15% (w/v) wheat bran and 48~72 hrs of incubation. The effects of liquid starters with different storage periods and temperatures (-18, 4, 10 and $25^{\circ}C$) on the quality of wheat nuruk were evaluated. According to the results of the pH, acidity, reducing sugar and enzyme activities, it was found that liquid starter using wheat bran preserved for one day, at any temperature, is the best method of storage for seed cultures for R. oryzae N174.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.242-246
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• 2002

Growth and tetraspore release pattern of lithophyllum yessoense (Rhodophyta, Corallinaceae) were investigated from March 2000 to July 2001. Pinkish tetraspores were 40.2 $\pm$ 0.4 $\mu$m in diameter. After release, tetraspores attached on substrate shortly. Culture conditions were five temperatures (5, 10, 15, 20, 25^{\circ}C), four irradiances (0, 20, 50, 100 $\mu$mol${\cdot}m^{-2}$${\cdot}s^{-1}$) and six salinities (0, 9, 17, 25, 34, 43 ppt). Maximum growth of gametophyte was occurred at $20^{\circ}C$, $20{\mu}mol\;m^{-2}$${\cdot}s^{-1}$, 16: 8h (L:D) and 34 put. Maximum relative growth rate was 0.1232 at $20^{\circ}C$. The amount of tetraspore release showed maximum at September as 266 cells per crust area ($cm^2$), and tetraspores did not release from January to March.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.398-405
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• 2016

The Schizosaccharomyces pombe structural gene encoding bacterioferritin comigratory protein (BCP) was previously cloned using the shuttle vector pRS316 to generate the BCP-overexpressing plasmid pBCP10. The present work aimed to evaluate the thermoresistant properties of BCP against high temperature stress using the plasmid pBCP10. When the S. pombe cells were grown to the early exponential phase and shifted from $30^{\circ}C$ to $37^{\circ}C$ or $42^{\circ}C$, the S. pombe cells harboring pBCP10 grew significantly more at both $37^{\circ}C$ and $42^{\circ}C$ than the vector control cells. After 6 h of the shifting to higher incubation temperatures, they contained the lower reactive oxygen species (ROS) and nitrite content, an index of nitric oxide (NO), than the vector control cells. After the temperature shifts, total glutathione (GSH) content and total superoxide dismutase (SOD) activities were much higher in the S. pombe cells harboring pBCP10 than in the corresponding vector control cells. Taken together, the S. pombe BCP plays a thermoresistant role which might be based upon its ability both to down-regulate ROS and NO levels and to up-regulate antioxidant components, such as total GSH and SOD, and subsequently to maintain thermal stability.

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.81-87
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• 2002

This study was conducted to investigate the cooling efficiency and growth of tomatoes by root zone cooling device using a pad-box and cultivated system. The structure of the root zone cooling system using a pad-box was four piece of pads bonded an the side and a fan set at the bottom. Cool wind was generated by the outside air which was punched at intervals of 10 cm along three rows. Cold wind flowed to the root zone in the culture medium. The root zone cooling efficiency of cold wind generation by using a pad-box flowing through a wet-pad was determined. Major characteristic of this cuttural system consist of bed filled with a perlite medium and a ventilation pipe using PVC. The cold wind generation by a pad box (CWP) was compared to that of cold wind generation by a radiator (CWR), cold water circulation using a XL-pipe (CWX) and the control (non-cooling). When the temperature of water supplied was 16.2-18.4$^{\circ}C$, temperatures in the medium were 20.5~23.2$^{\circ}C$ for CWP 22.7~24.2$^{\circ}C$ for CWR, 22.8~24.27$^{\circ}C$ for CWX and 23.1~-29.6$^{\circ}C$ for the control. The results show that the cold wind temperature using the pad-box was lower by 1~2$^{\circ}C$ than that of cold water circulation in the XL-pipe and lower by 5~6$^{\circ}C$ than that of the control. Growth such as leaf length, leaf width, fresh weight and dry weight, was greater in three root zone cooling methods than in the control. Root activity was higher in the rat zone cooling methods than in the control. However, there was no significant difference among root zone cooling methods.

• Journal of Mushroom
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• v.1 no.1
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• pp.34-43
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• 2003

This study was carried out to determine the proper pin-heading induction time(spawn running time) when different incubation temperature were applied to Pleurotus ostreatus(Chunchu 2ho, Suhan 1ho, Heukpyung). Incubation period was 17 days at 23 and 21 days at 17 for Chunchu 2ho, 17 days at 23 and 26 for Heukpyung, and 22~23 days at 17~23 for Suhan 1ho. Incubation period for Suhan 1ho was not significantly affected by incubation temperature. The time required for initial pin-heading was 4~5 days at 17, 20, 23 and 26 for Chunchu 2ho as well as Heukpyung, and was 3 days at 17, 20, 23 and 5~6 days at 26 for Suhan 1ho. As the incubation period became longer, the available fruit-bodies at Chunchu 2ho were made more but they were short. The yield of Chunchu 2ho and Heukpyung increased when incubated for 22~27 days at 20~23 and that of Suhan 1ho also increased when incubated for 22~23 days at 17~23.