• Journal of Applied Biological Chemistry
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• v.50 no.2
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• pp.46-51
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• 2007

Lipases are industrially useful versatile enzymes that catalyze numerous different reactions. Among lipases functioning under extreme conditions, alkaline lipase is useful in detergent industry. Lipase from yeast strain Yarrowia lipolytica NRRL Y-2178 was most active under alkaline condition, and initial medium pH for most lipase production was also alkaline [Lee et al., 2007, J Microbiol Biotechnol, 17(6)]. High lipase production was achieved using Y. lipolytica NRRL Y-2178. Optimal incubation time for lipase production at $25^{\circ}C$ was 72 h. Optimal temperature, when incubated for 72 h, was $27.5^{\circ}C$. Lipase production but not cell growth was very sensitive to concentrations of glucose and glycerol as efficient carbon sources, showing optimal concentrations of 1.0 and 1.5% (w/v), respectively. Lipase production was highly stimulated by $Ca^{2+},\;K^+,\;and\;Na^+$, but was inhibited by $Co^{2+},\;Cu^{2+},\;Mn^{2+},\;Na^+,\;and\;Fe^{2+}$. Maximum lipase production at 0.1 mM $Ca^{2+}$ for 72 h incubation at $27.5^{\circ}C$ was 649 units/mL.

• Journal of Mushroom
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• v.3 no.3
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• pp.109-114
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• 2005

Attempts were made to control Diatrype stigma occurred on the bed-log of shiitake by resistant shiitake strains. In selection test of resistant shiitake strains, 67 out of 77 strains tested were proved to be resistant to D. stigma. Among them, 13 strains including KFRI 5 were effective to inhibit the access of D. stigma, and 7 strains including KFRI 180 remarkably invaded the territory of D. stigma. Among 31 shiitake strains made by hybridization of resistant strains for D. stigma, 8 strains including KFRI 537 inhibited the access of D. stigma, and 4 strains including KFRI 545 invaded the territory of D. stigma. The effects of temperatures and inoculation orders to the resistance were confirmed in PDA plates and test tubes filled with sawdust of Quercus acutissima. Four kinds of temperature treatments as follows were tested: (1) continuous incubation at $14^{\circ}C$, (2) continuous incubation at $25^{\circ}C$, (3) changing of incubation temperature from $14^{\circ}C$ to $25^{\circ}C$ as soon as mycelia of both shiitake and D. stigma meet together, (4) changing of incubation temperature from $25^{\circ}C$ to $14^{\circ}C$ as soon as mycelia of both shiitake and D. stigma meet together. Three kinds of inoculation procedure were tested: (1) inoculation of shiitake 3 days ahead of D. stigma inoculation, (2) inoculation of D. stigma 3 days ahead of shiitake inoculation, (3) simultaneous inoculation of both fungi. In PDA plate test, the strain KFRI 137 showed outstanding ability to inhibit mycelial growth of D. stigma and the strain KFRI 180 invaded into the territory of D. stigma in most of treatments. Hybrid strains, KFRI 545, 546, and 547 were more resistant than their parent strains, KFRI 488 and 405. In test tube examinations, all the strains of shiitake showed high resistance at the treatment of change in temperature from $14^{\circ}C$ to $25^{\circ}C$ when mycelia of both shiitake and D. stigma meet together. On the other hand, resistance of all the strains growing at $25^{\circ}C$ decreased when the temperature was changed into $14^{\circ}C$ after mycelia of both fungi. In these cases, the resistance reached to 7~20% of the highest resistance. The strain KFRI 259 invaded the territory of D. stigma, contrary to PDA plate test. Among the strains, KFRI 393 strain was the most resistant under the continuous incubation at $25^{\circ}C$.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.3
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• pp.439-446
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• 2014

Many studies on methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from livestock industries have revealed that livestock production directly contributes to greenhouse gas (GHG) emissions through enteric fermentation and manure management, which causes negative impacts on animal environment sustainability. In the present study, three essential values for GHG emission were measured; i.e., i) maximum $CH_4$ producing capacity at mesophilic temperature ($37^{\circ}C$) from anaerobically stored manure in livestock category ($B_{0,KM}$, Korean livestock manure for $B_0$), ii) $EF_{3(s)}$ value representing an emission factor for direct $N_2O$ emissions from manure management system S in the country, kg $N_2O-N$ kg $N^{-1}$, at mesophilic ($37^{\circ}C$) and thermophilic ($55^{\circ}C$) temperatures, and iii) $N_{ex(T)}$ emissions showing annual N excretion for livestock category T, kg N $animal^{-1}$ $yr^{-1}$, from different livestock manure. Static incubation with and without aeration was performed to obtain the $N_2O$ and $CH_4$ emissions from each sample, respectively. Chemical compositions of pre- and post- incubated manure were analyzed. Contents of total solids (% TS) and volatile solid (% VS), and the ratio of carbon to nitrogen (C/N) decrease significantly in all the samples by C-containing biogas generation, whereas moisture content (%) and pH increased after incubation. A big difference of total nitrogen content was not observed in pre- and post-incubation during $CH_4$ and $N_2O$ emissions. $CH_4$ emissions (g $CH_4$ kg VS-1) from all the three manures (sows, layers and Korean cattle) were different and high C/N ratio resulted in high $CH_4$ emission. Similarly, $N_2O$ emission was found to be affected by % VS, pH, and temperature. The $B_{0,KM}$ values for sows, layers, and Korean cattle obtained at $37^{\circ}C$ are 0.0579, 0.0006, and 0.0828 $m^3$ $CH_4$ kg $VS^{-1}$, respectively, which are much less than the default values in IPCC guideline (GL) except the value from Korean cattle. For sows and Korean cattle, $N_{ex(T)}$ values of 7.67 and 28.19 kg N $yr^{-1}$, respectively, are 2.5 fold less than those values in IPCC GL as well. However, $N_{ex(T)}$ value of layers 0.63 kg N $yr^{-1}$ is very similar to the default value of 0.6 kg N $yr^{-1}$ in IPCC GLs for National greenhouse gas inventories for countries such as South Korea/Asia. The $EF_{3(s)}$ value obtained at $37^{\circ}C$ and $55^{\circ}C$ were found to be far less than the default value.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.3
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• pp.419-427
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• 2016

There is a high association of heat shock on the alteration of energy and lipid metabolism. The alterations associated with thermal stress are composed of gene expression changes and adaptation through biochemical responses. Previous study showed that Angelica gigas Nakai (AGN) root extract promoted adipogenic differentiation in murine 3T3-L1 preadipocytes under the normal temperature condition. However, its effect in heat shocked 3T3-L1 cells has not been established. In this study, we investigated the effect of AGN root hot water extract in the adipogenic differentiation of murine 3T3-L1 preadipocytes following heat shock and its possible mechanism of action. Thermal stress procedure was executed within the same stage of preadipocyte confluence (G0) through incubation at $42^{\circ}C$ for one hour and then allowed to recover at normal incubation temperature of $37^{\circ}C$ for another hour before AGN treatment for both cell viability assay and Oil Red O. Cell viability assay showed that AGN was able to dose dependently (0 to $400{\mu}g/mL$) increase cell proliferation under normal incubation temperature and also was able to prevent cytotoxicity due to heat shock accompanied by cell proliferation. Confluent preadipocytes were subjected into heat shock procedure, recovery and then AGN treatment prior to stimulation with the differentiation solution. Heat shocked preadipocytes exhibited reduced differentiation as supported by decreased amount of lipid accumulation in Oil Red O staining and triglyceride measurement. However, those heat shocked preadipocytes that then were given AGN extract showed a dose dependent increase in lipid accumulation as shown by both evaluation procedures. In line with these results, real-time polymerase chain reaction (RT-PCR) and Western blot analysis showed that AGN increased adipogenic differentiation by upregulating heat shock protection related genes and proteins together with the adipogenic markers. These findings imply the potential of AGN in heat shock amelioration among 3T3-L1 preadipocytes through heat shock factor and proteins augmentation and enhanced adipogenic marker expression.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.319-328
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• 2015

The $sdu1^+$ gene encodes Sdu1, a PPPDE superfamily member of deubiquitinating enzymes (DUBs) in Schizosaccharomyces pombe. Sdu1 was previously shown to contain an actual ubiquitin C-terminal hydrolase (UCH) activity using the recombinant plasmid pYSTP which harbors the $sdu1^+$ gene. This work was designed to assess a thermotolerant role of Sdu1 against high incubation temperatures. In the temperature-shift experiments, the S. pombe cells harboring pYSTP grew much better after the shifts to $37^{\circ}C$ and $42^{\circ}C$, when compared with the vector control cells. After being shifted to $37^{\circ}C$ and $42^{\circ}C$ for 6 h, the S. pombe cells harboring pYSTP contained lower reactive oxygen species (ROS) levels, compared with the vector control cells. The nitric oxide (NO) levels of the S. pombe cells harboring pYSTP were slightly lower than those of the vector control cells in the absence or presence of the temperature shifting. The total glutathione (GSH) levels of the S. pombe cells harboring pYSTP were significantly higher than those of the vector control cells. Total superoxide dismutase (SOD) and GSH peroxidase activities were also higher in the S. pombe cells harboring pYSTP after the temperature shifts than in the vector control cells. In brief, the S. pombe Sdu1 plays a thermotolerant role against high incubation temperature through the down-regulation of ROS and NO and the up-regulation of total GSH content, total SOD and GSH peroxidase activities.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.116-116
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• 2017

Low-temperature is one of the environmental stress factors that affect plant growth and development and consequently limit crop productivity. The control of seed germination under low-temperature is organized by many genes which are called quantitative trait loci (QTLs). High germination rate for low-temperature is an important factor of growing rice. Previously, we identified a major QTL controlling low-temperature germinability in rice using 96 introgression lines (ILs) derived from a cross between Oryza rufipogon (Rufi) and the Korean japonica cultivar, 'Hwaseongbyeo (HS)'. A $BC_3F_7$ line (TR5) showed better low-temperature germinability than its recurrent parent. TR5 was crossed with HS to develop a segregating F2:3 populations for the target QTL. Six SSR markers polymorphic between HS and Rufi were used to screen and fine map the qLTG1. The qLTG1 on chromosome 1, which accounted for 55.5% of the total phenotypic variation, confirmed that Rufi allele enhanced the low-temperature germinability. Intervals between markers CRM16 and CRM15, four candidate genes were identified. The identified candidate genes, which are encoded by a protein of unknown function, showed their direct involvement on seed germination at low-temperature. To identify genes targeted by qLTG1, we investigated the expression profiles of these candidate genes and germination behavior of qLTG1 under different stress conditions and compared to HS, Rufi, and TR5 at $13{\pm}2^{\circ}C$ for 3 days after incubation. Furthermore, transgenic rice plants will also be developed to conduct a detailed investigation on low-temperature germinability. Hence, the QTL for low-temperature germinability would be useful in rice breeding programs especially in the development of lines possessing low-temperature germinability.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.345-350
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• 2014

The aim of this study was to investigate the effect of high temperature on the viability of probiotic organisms (Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae) mixed with animal feed under controlled conditions by simulating a farm feed bin in the summer. Following inoculation of probiotics into the feed, the pH and probiotic viability were monitored during an 8-day incubation at room temperature. Sterile and non-sterile feeds displayed different patterns of pH changes, with increased pH in non-sterile feed at 2 days, but a pattern of decreasing pH at 4 days. The viabilities of S. cerevisiae and B. subtilis after mono/co-inoculation were maintained without substantial changes during the incubation, whereas L. plantarum viability tended to decline. In both non-sterile and sterile feeds, the probiotics were maintained or grew without any antagonistic effects. Probiotic viability was also tested upon a shift to high temperature ($60^{\circ}C$). There was no distinct change in pH between sterile and non-sterile feeds after the temperature shift. L. plantarum and S. cerevisiae could not survive at the high temperature, whereas B. subtilis displayed normal growth, and it inhibited the growth of contaminant microbes. Fungal growth was not observed in non-sterile feed 2 days after supplementation with B. subtilis. Therefore, heat resistant B. subtilis could be safely used in feed bins to inhibit microbial contamination, even at high temperatures. The prevention of elevated temperature in feed bins is necessary for the utilization of L. plantarum and S. cerevisiae during the summer season.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.457-460
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• 2002

In an effort to isolate novel strains expressing a thermostable esterase that hydrolyzed the rac-ketoprofen ethyl ester to ketoprofen in the stereospecific manner, we screened various soils and composts from broad ecological niches in which the activity was expected to be found. Three hundreds of microbial strains were tested to determine their ester-hydrolyzing activity by using an agar plate containing insoluble tributyrin as an indicative substrate, and then further screened by activity on the (R,S)-ketoprofen ethyl ester. Twenty-six strains were screened primarily at high growth and incubation temperature and further compared the ability to ethyl ester-hydrolyzing activity in terms of conversion yield and chiral specificity. Consequently, a strain JYl44 was isolated as a novel strain that produced a (R)-stereospecific esterase with high stability and systematically identified as a Bacillus stearothermophilus JY144. The enzyme indeed stables at a broad range of temperature, upto 65 $^{\circ}C$, and pH ranging from 6.0 to 10.0. The optimal temperature and pH for enzymatic conversion were 50 $^{\circ}C$ and 9.0, respectively. Based on the observations that resulted a poor cell growth, and enzyme expression in wild type strain, we further attempted the gene cloning into a general host Escherichia coli and determined its primary structure, concomitantly resulting a high level expression of the enzyme. The cloned gene had an open reading frame (250 amino acids) with a calculated molecular mass of 27.4 kDa, and its primary structure showed a relative high homology (45-52 %) to the esterases from Streptomyces and Bacillus strains. The recombinant whole cell enzyme could efficiently convert the rac-ketoprofen ethyl ester to (R)-ketoprofen, with optical purity of 99 % and yield of 49 %.

• Elastomers and Composites
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• v.48 no.2
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• pp.133-140
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• 2013

Carbon fiber reinforced polymer (CFRP) composites consist of carbon fibers in a polymer matrix. Recently, CFRP composites having high thermal stability and low outgassing are finding their use in high performance materials for aerospace and electronics applications under high temperature and high vacuum conditions. Cyanate ester resin is one of the most suitable matrix resins for this purpose. In this study, proper combination of cyanate ester and catalyst, curing behavior, and cure cycle were determined by chemorheology. Optimum condition was found to be catalyst content of 100 ppm and curing temperature of $150^{\circ}C$. Thermal stability and outgassing of cured resin composition were analyzed and the results showed thermal decomposition temperature of $385^{\circ}C$ and total mass loss of 0.29%. The CFRP prepregs and subsequent composites were fabricated by predetermined resin composition and the cure condition. Tensile moduli of the composites were compared with theoretical models and the results were very consistent.

• The Korean Journal of Pharmacology
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• v.18 no.2
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• pp.33-44
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• 1982

The binding in vitro of an opiate agonist, $(^3H)-morphine$, was studied using rat brain slices which were incubated in the modified Krebs-Henseleit bicarbonate buffer solution containing various concentrations of electrolytes with or without morphine, naloxone or morphine+naloxone at $4^{\circ}C$ for 24 hours. The binding of $(^3H)-morphine$ may be seperated into two component; one a saturable binding and the other nonsaturable. The saturable binding may be calculated from the differences in binding observed in the absence and presence of high concentration of morphine. The maximal saturable binding and $K_D$ value in the naive preparations were $0.32{\pm}0.02\;pmole/mg$ protein and $0.75{\pm}0.07\;nM$ respectively. The saturable binding of $(^3H)-morphine$ was significantly increased by low temperature-treatment, while $K_D$ value was not changed. Morphine in the incubation media significantly increased the saturable binding of $(^3H)-morphine$ and $K_D$ value. Naloxone also increased the maximal saturable binding of $(^3H)-morphine$ and $K_D$ value of the drug. Decrease of $K^+\;and\;Mg^{++}$, and addition of $Mn^{++}$ in the incubation media significantly increased the saturable binding of $(^3H)-morphine$, but decrease of $Na^+$and increase of $Ca^{++}$ in the incubation media did not influence the binding. The increment of the saturable binding of $(^3H)-morphine$ by nonlabeled morphine in the incubation media was notaffected by decrease of $Na^+,\;K^+\;or\;Mg^{++}$, or addition of $Mn^{++}$ into the incubation media, but was inhibited by increase of $Ca^{++}$ in the incubation media, while the increment of the saturable binding of $(^3H)-morphine$ was net observed by decrease of $Na^+,\;K^+\;or\;Mg^{++}$, or increase of $Ca^{++}$ in the incubation media. The above results indicate that change of opiate binding sites in quality, i.e. affinity, and quantity, i.e. number of binding sites, may occur by low temperature-treatment in the absence and presence of morphine or naloxone and that electrolytes play role of the changes of opiate binding sites.