• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.42-48
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• 2014

In this study, variations of the organic and nitrogenous compounds in wastewater were investigated in a single reactor with intermittent aeration. Over 90% of organic and nitrogen removals are accomplished with C/N ratio of 3 : 1 and 20/20 min of aeration/non-aeration period. Longer non-aeration period on the aeration/non-aeration cycle showed more stable nitrogen removal, showing various microbial community in the reactor. From PCR-DGGE analysis, it is conclusive that Dysgonomonas mossii strain Melo40, Eubacterium sp. oral clone JN088, Uncultured bacterium clone SPESB2_718, and Bacterium enrichment culture clone LE are related with the organics and nitrogen oxidation. Uncultured Acidobacteria bacterium clone AKYG487, Lactobacillus harbinensis strain FQ003, Erythrobacter litoralis strain Gi-3, Phytobacter diazotrophicus strain Ls8, and Mycobacterium sp. enrichment culture clone GE10037biofNNA are distinctly appeared under denitrification condition.

• Journal of Forest and Environmental Science
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• v.38 no.4
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• pp.249-255
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• 2022

The study was conducted to establish a method for the proliferation of hybrid poplar (P. alba × P. glandulosa) clone Bongwha1, an excellent biomass species. It was found that to collect the cuttings of Bonghwa1, it was necessary to use the main stem rather than the axillary branch. Stem growth by green-wood cuttings showed a tendency to decrease as the length of the collected cuttings increased, but the survival rate was low. Therefore, modified leafy stem cutting was attempted to increase the survival rate of the cuttings. In the modified leafy stem cutting method, 4 leaves were included in the cuttings, and especially, cuttings were performed using cuttings containing 2-4 cm xylem parts. Leafy stem cutting increased root growth and the number of stems, as well as the survival rate of hybrid poplar clone Bongwha1 compared to green-wood cuttings. The root growth of the leafy stem cutting poplar was better as there was more xylem part. Using two-year-old nursery stocks, the leafy stem cutting was used to produce about 66 cuttings. This study is expected to contribute to the mass propagation of high-quality nursery stocks.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.712-720
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• 2007

To investigate clonal variations of recombinant Chinese hamster ovary(rCHO) clones in response to culture pH and temperature, serum-free suspension cultures of two antibody-producing CHO clones(clones A and B), which were isolated from the same parental clone by the limiting dilution method, were performed in a bioreactor at pH values in the range of 6.8-7.6, and two different temperatures, $33^{\circ}C\;and\;37^{\circ}C$. In regard to cell growth, clone A and clone B displayed similar responses to temperature, although their degree of response differed. In contrast, clones A and B displayed different responses to temperature in regard to antibody production. In the case of clone A, no significant increase in maximum antibody concentration was achieved by lowering the culture temperature. The maximum antibody concentration obtained at $33^{\circ}C$(pH 7.4) and $37^{\circ}C$(pH 7.0) were $82.0{\pm}2.6$ and $73.2{\pm}4.1{\mu}g/ml$, respectively. On the other hand, in the case of clone B, an approximately 2.5-fold increase in maximum antibody concentration was achieved by lowering the culture temperature. The enhanced maximum antibody concentration of clone B at $33^{\circ}C$($132.6{\pm}14.9{\mu}g/ml$ at pH 7.2) was due to not only enhanced specific antibody productivity but also to prolonged culture longevity. At $33^{\circ}C$, the culture longevity of clone A also improved, but not as much as that of clone B. Taken together, CHO clones derived from the same parental clone displayed quite different responses to culture temperature and pH with regards antibody production, suggesting that environmental parameters such as temperature and pH should be optimized for each CHO clone.

• The Korean Journal of Ecology
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• v.24 no.2
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• pp.93-100
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• 2001

One-year-old cottonwood (Populus deltoides Bartr.) clones, which were classified as sensitive or tolerant, were exposed to 150 n1/1 ozone (O$_3$) over 8 days for 8 hours each day under glass chamber conditions with natural sunlight. The leaves of the sensitive clone had black stipple and bifacial necrosis after $O_3$ treatment. Photosynthesis and stomatal conductance were measured before, during, and after the $O_3$ treatment. The photosynthetic rates due to $O_3$ treatment were decreased 51 percent and 34 percent on the sensitive and tolerant clone, respectively. The stomatal conductance of the sensitive clone was more than 40 percent higher than that of the tolerant clone regardless of the $O_3$ treatment. As light intensity increased, the $O_3$ effect on photosynthesis was clear. Compared to the previous growth chamber studies, our natural light exposure system was able to maintain a stable photosynthetic responses of the control treatment throughout the fumigation period. In addition, changes in assimilation versus intercellular $CO_2$ concentration (A/C curves) showed that $O_3$ decreased the slope and asymptote of the curves for the sensitive clone. This indicates that $O_3$ decreases the biochemical capacity of photosynthesis on the sensitive clone. Chlorophyll contents and fluorescence of the two clones were analyzed to examine the $O_3$ effects on photosystem 11, but $O_3$ did not impact these variables on either clone. Although the tolerant clone did not show any foliar injury, we could not find any ecophysiological defensive responses to $O_3$ treated. Stomatal conductance of the tolerant clone was originally much lower than that of the sensitive one. Thus, the mechanisms of the tolerant clone in this system are to narrowly open stomata and efficiently maintain photosynthesis with a more durable biochemical apparatus of photosynthesis under $O_3$ stress. The sensitive clone has higher photosynthetic capacity and more efficient light reaction activity than the tolerant one under charcoal filtered condition, but is not as resilient under stress.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.5
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• pp.40-50
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• 2007

One-year-old rooted cuttings of ten poplar clones and one willow clone were planted in a riparian area in Osan. Survival rate, growth performance, biomass, vitality, defoliation, leaf damages by diseases and/or insects and stem borer damage of the poplar and willow clones have been investigated for three growing seasons. Average survival rate of all eleven clones was declined from 80.7% for the first year to 60.7% for the third year. At three years after planting, poplar clones Dorskamp, ST-148 and Eco-28 showed the best survival rate of 80%. For height and DBH growth, the poplar clone Ay-48 and the willow clone 131-25 were the highest 8.3m and 9.5cm, respectively. However, poplar clones 72-30 and 72-31 were lower than those of the other clones. Clones Ay-48 and 131-25 seemed to have strong vitality when compare to the other clones. No serious damages by diseases and insects were found in most clones. Clones Ay-48 and ST-148 were the most tolerant to various diseases and insects. Clone Ay-48 produced the largest biomass for individual and annual total biomass, 22.5kg and 18.7ton $ha^{-1}$, respectively. Clone Dorskamp showed the best adaptability, which was estimated with survival rate, biomass and damages by various diseases and insects in the riparian area and followed by clones Ay-48, 97-19 and Eco-28. As a consequence, the four clones seemed to be the best candidate poplar clones for the establishment of riparian woody buffer.

• Korean Journal of Environmental Biology
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• v.22 no.2
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• pp.336-340
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• 2004

In order to search for anti -melanin formation agents from Korean medicinal herbs, we selected 21 Korean medicinal herbs, based on a review of Korean traditional medicine books and the recommendations of Korean traditional medical doctors. We tested for inhibition effect of melanin pigmentation of Clone M-3 mouse melanocyte cell lines when we treated the extracts of 21 medicinal herbs in the mouse melanocyte cell lines, respectively. Among 21 medicinal herb extracts, 5 extracts showed a inhibition effect of melanin formation. The sample Phaseolus radiatus L, Cordyceps militaris, Pinellia ternata, Phellinus linteus and Citrus junos Tanaka showed a significantly little formation of melanin pigments compared with control groups. Especially extract of Citrus junos Tanaka was more potent than the others. These results suggest that extract of Korean Citrus junos may represents an excellent candidate for inhibition of melanin pigmentation at in vitro level.

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.28-34
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• 2019

This study analyzed the occurrence pattern of Dolichospermum (= Anabaena) in the Bukhan river from March 2012 to December 2014 in order to identify the genotypes of Dolichospermum. Furthermore, 16S rRNA were analyzed to identify the genotypes of Dolichospermum that occurred in 2015 which were then compared to the reference sequence deposited at NCBI. During this period, the occurrence of Dolichospermum was highly correlated to water temperature. In the year 2012 and 2013, Dolichospermum appeared in Lake Cheongpyeong (CP), Sambong (SB), and Lake Paldang (P2) between July and August. However, in 2014, it appeared in SB and P2, but not in CP. This reduction in appearance was attributed to the decreased inflow to Lake Uiam as a result of low rainfall in 2014 as compared to 2012. In July 2015, the Dolichospermum 16S rRNA genotype was confirmed in five locations; Lake Cheongpyeong (CP), Seojong (SJ), Songchon Sewage Treatment Plant (SC), Joan (P4), and Lake Paldang (PD). Anabaena crassa of spiral clone, A. planctonica of linear clone, and A. circinalis of spiral clone exhibited high genetic similarity with the reference sequence. The 16r RNA genotype showed approximately 3 % sequence variation between the locations and were more similar to each other in locations that were closer.

• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.152-156
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• 2012

Methanotrophic communities from freshwater wetland (FW), seawater wetland (SW), forest (FS), and landfill soils (LS) around Seoul of South Korea, were characterized using comparative sequence analyses of clone libraries. Proportions of Methylocaldum, Methlyococcus and Methylosinus were found to be greater in FW and SW, while Methylobacter and Methylomonas were more notable in FS and Methylocystis and Methylomicrobium more prominent in LS. Lag periods behind the initiation of methane oxidation significantly varied amongst the soils. Methane oxidation rates were greater in $FW{\geq}LS{\geq}SW>FS$ (p<0.05). Thus, the environmental setting is a significant factor influencing the communities and capabilities of methanotrophs.

• Journal of Microbiology
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• v.44 no.2
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• pp.155-161
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• 2006

Comparative analysis of microbial communities in a sequencing batch reactor which performed enhanced biological phosphorus removal (EBPR) was carried out using a cultivation-based technique and 16S rRNA gene clone libraries. A standard PCR protocol and a modified PCR protocol with low PCR cycle was applied to the two clone libraries of the 16S rRNA gene sequences obtained from EBPR sludge, respectively, and the resulting 424 clones were analyzed using restriction fragment length polymorphisms (RFLPs) on 16S rRNA gene inserts. Comparison of two clone libraries showed that the modified PCR protocol decreased the incidence of distinct fragment patterns from about 63 % (137 of 217) in the standard PCR method to about 34 % (70 of 207) under the modified protocol, suggesting that just a low level of PCR cycling (5 cycles after 15 cycles) can significantly reduce the formation of chimeric DNA in the final PCR products. Phylogenetic analysis of 81 groups with distinct RFLP patterns that were obtained using the modified PCR method revealed that the clones were affiliated with at least 11 phyla or classes of the domain Bacteria. However, the analyses of 327 colonies, which were grouped into just 41 distinct types by RFLP analysis, showed that they could be classified into five major bacterial lineages: ${\alpha},\;{\beta},\;{\gamma}-$ Proteobacteria, Actinobacteria, and the phylum Bacteroidetes, which indicated that the microbial community yielded from the cultivation-based method was still much simpler than that yielded from the PCR-based molecular method. In this study, the discrepancy observed between the communities obtained from PCR-based and cultivation-based methods seems to result from low culturabilities of bacteria or PCR bias even though modified culture and PCR methods were used. Therefore, continuous development of PCR protocol and cultivation techniques is needed to reduce this discrepancy.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.361-368
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• 2005

A Korean isolate of Pepper mild mottle virus (PMMoV-Kr) was isolated from a diseased hot pepper plant and its biological and molecular properties were compared to that of PMMoV-J and PMMo V -So The genomic RNA of PMMoV-Kr consists of 6,356 nucleotides. The nucleotide and amino acid sequences identities of four viral proteins and two noncoding regions among PMMoV-Kr, PMMoV-S and PMMoV-J were $96.9\%\;to\;100.0\%\;and\;97.5\%\;to\;98.6\%$, respectively. Full-length cDNA amplicon of PMMoV-Kr was directly amplified by RT-PCR with a set of 5'-end primer anchoring T7 RNA promoter sequence and 3'-end virus-specific primer. Capped transcript RNAs from the full-length cDNA clone were highly infectious and caused characteristic symptoms of wild type PMMoV when mechanically inoculated to systemic host plants such as Nicotiana benthamiana and pepper plants.