• Korean Journal of Veterinary Research
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• v.48 no.3
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• pp.337-345
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• 2008

There are accumulating evidences that high levels of dietary iron may play a role in colon carcinogenesis. Elevated iron status has been associated with oxidative stress. Phytic acid (PA) functions as an antioxidant by chelating divalent cations and prevents formation of reactive oxygen species responsible for cell injury and carcinogenesis. The protective effect of PA was investigated on formation of aberrant crypt foci (ACF) induced by azoxymethane (AOM) in iron-overloaded male F344 rats. After acclimation with AIN-93G purified diet (35 ppm Fe, normal control diet) for one week, animals were fed iron-overloaded diet (350 ppm Fe) and PA (0.5% or 2% PA in water) for 8 weeks. Animals received two (1st and 2nd week) injections of AOM (15 mg/kg b.w.) to induce colonic ACF. The colonic mucosa was examined for the total numbers of aberrant crypt (AC) and ACF after staining with methylene blue. The blood and serum were analyzed with a blood cell differential counter and an automatic serum analyzer. Iron-overloaded diet increased the concentration of iron in liver of the rats. But iron-related parameters in blood were not changed among experimental groups. The numbers of ACF per colon and AC per colon were $178.8{\pm}33.2$ and $448.4{\pm}110.2$ in the iron-overloaded F344 rats. The total AC was significantly increased, compared with normal-diet AOM control group (p < 0.05). The treatments of PA at the dose of 0.5% slightly decreased the number of ACF and AC per colon to $153.6{\pm}29.5$ and $396.3{\pm}107.5$. However, there were no significant differences in the total numbers of ACF and AC between the AOM control group and PA (0.5% or 2%)-treated groups. These results suggest that PA may not affect the formation of ACF or AC induced by AOM in ironoverloaded F344 rats.

• Korean Journal of Medicinal Crop Science
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• v.7 no.2
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• pp.94-100
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• 1999

To establish the mass propagation system of Lavandula spica cv. Marino, shoot tip, node, internode and leaf segment cultures were carried out. RAPD was applied to detect the somaclonal variation. Callus induction was very high in the medium supplemented with 1 mg/l 2.4-D, 2 mg/l NAA. especially and combined with 0.05 mg/l BAP from leaves. Shoot formation was high with $2{\sim}4\;mg/l$ BAP or 4 mg/l BAP + 0.2 mg/l NAA from shoot tip. Shoot proliferation was 9.1 times in the $B_{5}$ medium with 0.5 mg/l BAP and 0.01 mg/l NAA. Root formation was improved in NAA, which was the concentration of 0.1 to 1 mg/l and 1 mg/l IAA. Nursery survival rate was enhanced over 90% and growth was looked good in the acclimation soil consisting of peatmoss : vermiculite : perlite (1:1:1, v:v:v). Randomly amplified polymorphic DNA banding patterns based on polymerase chain reaction (PCR) were used to assess the genetic variation in plants regenerated from in vitro culture.

• Korean Journal of Medicinal Crop Science
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• v.15 no.5
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• pp.339-345
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• 2007

Field performance and morphological characterization was conducted on seven transgenic lines of Codonopsis lanceolata expressing ${\gamma}-TMT$ gene. The shoots were obtained from leaf explants after co-cultivation with Agrobacterium tume-faciens strain LBA 4404 harboring a binary vector pYBI 121 that carried genes encoding ${\gamma}-Tocopherol$ methyltransferase gene (${\gamma}-TMT$) and a neomycin phosphotransferase II gene (npt II) for kanamycin resistance. The transgenic plants were transferred to a green house for acclimation. Integration of T-DNA into the $T_0\;and\;T_1$ generation of transgenic Codonopsis lanceolata genome was confirmed by the polymerase chain reaction and southern blot analysis. The progenies of transgenic plants showed phenotypic differences within the different lines and with relative to control plants. When grown in field, the transgenic plants in general exhibited increased fertility, significant improvement in the shoot weight, root weight, shoot height and rachis length with relation to the control plants. However, all seven independently derived transgenic lines produced normal flower with respect to its shape, size, color and seeds number at its maturity. Indicating that the addition of a selectable marker gene in the plant genome does not effect on seed germination and agronomic performance of transgenic Codonopsis lanceolata. $T_1$ progenies of these plants were obtained and evaluated together with control plant in a field experiment. Overall, the agronomic performance of $T_1$ progenies of transgenic Codonopsis lanceolata showed superior to that of the seed derived non-transgenic plant. In this study, we report on the morphological variation and agronomic performance of transgenic Codonopsis lanceolata developed by Agrobacterium transformation.

• Journal of Environmental Science International
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• v.20 no.8
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• pp.943-951
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• 2011

We investigated the effects of temperature changes on the oxygen consumption rhythm in Japanese eels, Anguilla japonica, using an automatic intermittent flow respirometer (AIFR). The endogenous rhythm of the oxygen consumption rate (OCR) in the eels (n = 18; 44-74 cm, 145-690 g), freshly collected by bag net from estuaries, was nearly synchronous with the tidal pattern of the estuarine collection site. The magnitude of mean OCR (mOCR) of eels showed variable range of 82.2 - 116.5 ml $O_2\;kg^{-1}ww \;h^{-1}$ under constant conditions. In case of increasing temperature from 25 to $38^{\circ}C$, the OCR of eels exhibited a gradually increasing trend with a rhythmic pattern until $36^{\circ}C$. Above $36^{\circ}C$ the rhythms of the OCR dampened and the OCR decreased rapidly at around $36-37^{\circ}C$. The OCR of the eels exhibited the maximum value at $38^{\circ}C$, and then it sharply decreased. The results suggested that the critical thermal maximum (CTM) regarding the endogenous rhythms of the eels was at around $36-37^{\circ}C$ when water temperature increased at $0.5^{\circ}C$/14 h following the acclimation at $25^{\circ}C$. In case of decreasing temperature ($0.5^{\circ}C$/14 h) from 25 to $0^{\circ}C$, the OCR of the eels displayed a abrupt decrease up to $23^{\circ}C$, and between at 23 and $20^{\circ}C$, there was an agitation which showed a slight increase in the OCR with a duration of 1-2 days. Below $9^{\circ}C$, the OCR rhythm of the eels showed a constant state regardless of temperature decreasing. These results suggest that the Japanese eel has an upper incipient lethal temperature at $36^{\circ}C$, with a lower thermal limit at $9^{\circ}C$. The biochemical aspects of the eels influenced by water temperature need to be further studied.

• Korean Journal of Plant Tissue Culture
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• v.21 no.2
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• pp.85-90
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• 1994

Attempts were made to regenerate plants from petiole explane of Forest Pimpinella barchycarpa via repetitive somatic embryogenesis. Effective induction of somatic emb교ogenesis was achieved on both MS and modified $B_{5}\;(mB_{5})$ media containing BA + 2,4-D or BA + 2,4-D + NAA under light condition (16-h photoperiod/day) cultures. The explants exposed to the ligt produced numerous somatic embryos while those kept under the dark did not form any on the same medium. Somatic embryos at different developmental stages were observed to arise within a individual explants. Plantlets could be regenerated on $mB_{5}$ basal medium or $mB_{5}$ containing 0.1 mg/L NAA Secondary adventive embryos were formed on the surface of the somatic embryos. Therefore, repetitive somatic embryogenesis could be achieved by secondary embryogenesis. Although the treatment of 2,4-D or NAA alone was effective in callus formation and growth, but not in induction of somatic embryogenesis. Some explants, cultured on NAA-containing media in darkness, produced only adventive roots. The embryogenic potential was maintained for two years when subcultured to BA and 2,4-D containing media with 5 weeks inteval. Regenerated plantlets were maintained on $mB_{5}$ or MS basal media for 4 to 6 more weeks and transferred to soil of an artificial mixture for acclimation. Most plantlets (more than 97%) survived, and grew without any deformity.

• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.9-16
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• 2010

Osmoregulatory capabilities of a euryhaline medaka, Oryzias dancena (Beloniformes; Teleostei), was examined with a particular emphasis on adult and larval viability during direct salinity changes. O. dancena adults were highly capable for hyper-osmoregulation as well as hypo-osmoregulation, as evidenced by no adverse effect on their viability during the direct transfer either from complete freshwater ($0^{\circ}/_{\circ\circ}$) to $40^{\circ}/_{\circ\circ}$ salinity, or from $70^{\circ}/_{\circ\circ}$ to $0^{\circ}/_{\circ\circ}$. Furthermore, the phased increase of external salinity with acclimation periods allowed them to survive at a salinity as high as $75^{\circ}/_{\circ\circ}$. However, tolerant capability to acute salinity increase in early larval stage was much less than in adult stage, based on the finding that the tolerance range of salinity increase was only $15^{\circ}/_{\circ\circ}$ from freshwater, indicating that the hyper-osmoregulation system might not be fully developed in the early larval stage. On the contrary, the hypoosmoregulation system could be more solidified in O. dancena larvae, as evidenced by their good survival even after direct transfer from $45^{\circ}/_{\circ\circ}$ to $0^{\circ}/_{\circ\circ}$. Knowledge achieved in this study could form the basis for a wide scope of researches including ecotoxicogenomics and geneexpression assay using this model species.

• Development and Reproduction
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• v.16 no.2
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• pp.77-85
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• 2012

Various cryoprotective agents (CPA) were tested to establish the best conditions for the cryopreservation of sperm from black porgy Acanthopagrus schlegeli acclimated and raised in freshwater (BFW). Survival rates of frozen/thawed sperm from BFW were higher in the order of dimethy sulfoxide (DMSO), glycerol, ethylene glycol (EG) and methanol. Sperm motility was higher in the order of glycerol, DMSO, EG and methanol. These effects were the same in thawed sperm from black porgy raised in seawater (BSW). Thus, optimum CPA for sperm cryopreservation of BFW and BSW were DMSO and glycerol where the highest survival rates and sperm motility were found at the concentration of 10%. In particular, the survival rates and motility of thawed sperm from BFW and BSW after cryopreservation using 10% DMSO were better than when cryopreserved using 10% glycerol. On the other hand, for the thawed sperm from both BFW and BSW, the longer the preservation period was, the lower the survival rates and sperm motility were. Notably, the higher the concentration of CPA was, the lower the survival rates and sperm motility were.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.138-144
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• 2008

The effects of salinity on oxygen consumption, operculum movement number and ammonia nitrogen excretion were examined in cultured tilapia, Oreochromis mossambicus (total length 10$\pm$1.0 cm, total weight 17.3$\pm$4.2 g). The fish were exposured to certain salinities (0, 3, 9, 15, 21, 27 and 32 psu) step by step with 3 psu$\cdot$d$^{-1}$ and changed rapidly from certain salinity to another salinity. The oxygen consumption of the fish which was transferred step by step showed increasing tendency in the range of 3 $\sim$ 27 psu, but markedly appeared very low value at 32 psu. The tolerance limit in tilapia by salinity change without acclimation was shown 23.3 psu from 96-h TL$_{50}$. The oxygen consumption, operculum movement and ammonia nitrogen excretion of fish which was transferred rapidly from certain salinity to each salinity (0, 9, 15, 21 and 32 psu) showed a changing point at 15 psu; they showed increasing and/or decreasing pattern before 15 psu, and showed decreasing pattern after 15 psu. From these results, it was concluded that the appropriate salinity without physiological change for Java tilapia was below 15 psu.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.53-59
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• 2012

This study investigated characteristics of decomposition of tetrabutoxysilane (TBOS) as a slow release substrate (SRS) and on effect of TBOS decompostion compounds (acetate and butylate) for anaerobic dechlorination of trichloroethylene (TCE). In the batch experiment, TCE, cis-dichloroethene (cis-DCE), 1-butanol and TBOS were analysed by GC/FID and acetate and butylate were measured by HPLC. 1M of TBOS transferred and accumulated 4M of 1-butanol by abiotically hydrolysis reaction. The hydrolysis rate was in a range of 0.186 ${\mu}M/day$. On other hand, 1-butanol fermented to butyrate and acetate with indigenous culture from natural sediments. This results showed that TBOS could be used a slow release substrate in the natural sites. The dechlorinated potential of TCE with acetate and butyrate was increased with a decreasing initial TCE concentrations. In addition, first order coefficients of dechlorination with acetate as electron donor was higher then that with butyrate. It is because that dechlorination of Geobacter lovleyi was affected by substrate affinity, biodegradability and microbial acclimation on various substrates. However, dechlorinated potential of Geobacter lovleyi was decreased with accumulation cis-DCE in the anaerobic decholoronation process. The overall results indicated that SRS with Geobacter lovleyi might be a promising material for enhancing dechlorination of TCE on natural site and cis-DCE should be treated by ZVI as reductive material or by coexisting other dechlorinated bacteria.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.2
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• pp.25-34
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• 1999

The effects of copper on the anaerobic degradation of propionate were studied using anaerobic batch reactors. The apparent inhibitory effects of copper on the anaerobic degradation of propionate could be observed from behaviors of intermediates, ultimate methane yield(UMY) and specific methanogenic activity(SMA) There was little inhibition at the concentration of $2.5mg\;Cu^{2+}/L$. Beyond this concentration, the inhibitory effects increased with increasing dose of coppers. The 50% inhibition of UMY and SMA occurred at copper dosage of 33.8 and $24.1mg\;Cu^{2+}/gVSS$, respectively. The inhibitory effect based on the UMY was gradually reduced with the operation time dueprobably to the acclimation of microorganisms and/or binding of the added copper by ligands(and possibly ion exchange sites)contained on the cell membrane and extracellular polymer matrix whereas it based on the SMA might exclude the this phenomena. Therefore, the methodology for interpretation of inhibition data based on the SMA was more accurated than the UMY. There was no inhibitory effect in batch reactors supplemented with sulfate due to an antagonistic action of the sulfate reducing bacteria. Propionate degradation was initially retarded for copper inhibited samples but it gradually degraded afterward. Based on the mass removal considering take into account the propionate to acetate conversion, propionate degradation may appeal more affected than acetate. This result revealed that the hydrogenotrophic methanogens were the most affected by copper.