• Journal of Life Science
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• v.28 no.3
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• pp.376-387
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• 2018

Among a variety of environmental stresses heat, cold, chilling, high salt, drought, and so on exposed to plants, drought stress has been reported as a crucial factor to adversely affect the growth and productivity of plants. Therefore, to understand the mechanism for the drought stress signal transduction pathway in plants is more helpful to develop useful crops that display the enhanced tolerance against drought stress, and to expand crop growing areas. The signal transduction pathway for the drought stress in plants is largely categorized into two types; ABA-dependent pathway and ABA-independent pathway. It has been reported that two transcription factors, AREB/ABF and DREB2, play predominant roles in ABA-dependent and ABA-independent pathways, respectively. In addition to transcriptional regulation mediated by AREB/ABF and DREB2 transcription factors, post-translational modification (such as phosphorylation and ubiquitination) and epigenetic control are importantly involved in the signal transduction for drought stress. In this paper, we review current understanding of signal transduction pathway on drought stress in plants, especially focusing on the biological roles of a variety of signaling components related to drought stress response. Further understanding the mechanism of drought resistance in plants through this review will be useful to establish theoretical basis for developing drought tolerant crops in the future.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.69-75
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• 2017

Dormancy-associated protein (DRM) is involved in the dormancy physiology of plants and is conserved in almost all plant species. Recent studies found that DRM genes are involved in the abiotic stress response, and characterization studies of these genes have been conducted in several plants. However, few studies have focused on DRM genes in woody plants. Therefore, in this study, cDNA coding for DRM (PagDRM1) was isolated from poplar (Populus alba ${\times}$ P. glandulosa), and its structure and expression characteristics were investigated. PagDRM1 encodes a putative protein composed of 123 amino acids, and the protein contains two conserved domains (Domain I and Domain II). PagDRM1 is present as one or two copies in the poplar genome. Its expression level was highest in the stem, followed by mature leaves, roots, and flowers. During the growth of cultured cells in suspension, PagDRM1 was highly expressed from the late-exponential phase to the stationary phase. In addition, PagDRM1 expression increased in response to drought, salt stress, and treatment with plant hormones (e.g., abscisic acid and gibberellic acid). Therefore, we suggested that PagDRM1 not only plays an important role in the induction of dormancy, but also contributes to stress tolerance in plants.

• Journal of Plant Biology
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• v.14 no.4
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• pp.27-33
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• 1971

Information this research an attempt was made to investigate the plant community structure and the process of its formation in the tidal area surrounding Mokpo City the examined area included the stand in Sam-Hak Do wherein sands have inflowed, and the stand in Kat-Ba-Woo which has been left as tidal soil land. Two hundred stands were sampled by making 100m line transects 5m apart and establishing 30cm$\times$30cm quadrates 10m apart on each tape. These data were used to establish frequency, cover degree, density, standing crop (g/$m^2$), contained Cl in the soil, and pH. Results of the research are as following: 1. There were 25 species of plants in the stands from Sam-Hak Do, 18 in the stands from Kat-Ba-Woo, and so 28 species in all. Regardings the importance value, the rank of dominant species is Salicornia herbacea L., Suaeda maritima Dumorties, Diplachne fusca L., Echinochola hispidula Nakai, Cyperus iria L., Setaria lutescens Hubbard in Sam-Hak Do, and Suaeda maritima Dumorties, Echinochloa hispidula Nakai, Aster tripolium L., Scripus maritimus L., Salicornia herbacea L., Diplachne fusca L., in the lands from Kat-Ba-Woo. Among them are five kinds of halophytes Salicornia herbacea L., Suaeda maritima Dumorties, Atriplex Gmelini C.A. Meyer, Aster tripolium L., and Limonium tetragonum Bullock; and two Kinds of naturalized plants Diplachan fusca L., Aster subulata. M. In the stands from Sam-Hak Do there was evidence of a secondary succession phenomena in the presence of Cyperaceae such as Cyperus liria L., Juncus decipiens Nakai, and Fimbristylis longispica Steudal, which could not be found in the stands from Kat-Ba-Woo. 2. On the number of species of vegetation, the further inland from the floodgate the higher the number; that is, the lower the content of Cl the higher the number of species. 3. On the distribution of the vegetation; comparing DFD index and Cl content, the main plants are Salicornia herbacea L., Suaeda maritima Dumorties, Atriplex gmelini C.A. Meyer, Diplachne fuscal, Echinochola hispidula Nakai where the Cl content of soil is more than 13.2%. 4. On the standing crop; Salicornia herbacea L., which has high resistance to salt, was half the total was production of 1090/$m^2$ while Suaeda maritima Dumorties was 1/4, Diplachne fusca L. 1/8, and Echinochloa the least. Analyzing the result, the research indicates that the main factor in plant community formation in tidal land is tolerance for Cl, and that a plan for utilizing the halophytes which are abundant in tidal land should be devised.

• Journal of Life Science
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• v.24 no.11
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• pp.1231-1237
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• 2014

The objective of this study was to evaluate the safety and functional properties of four potential probiotic strains isolated from Kimchi, traditional Korean fermented vegetables. Based on being higher tolerance to bile salts and showing higher acid resistance or hydrophobic properties, one Lactobacillus arizonensis strain (BCNU 9032) and three L. brevis strains (BCNU 9037, BCNU 9098 and BCNU 9101) were selected in the screening experiment. All strains can survived up to 99% after 3h culture in pH 2.5 and resistant to 1% bile salts. These strains also showed good antimicrobial activities against a number of food borne pathogens, especially against Escherichia coli and Shigella sonnei. The ability to lower cholesterol levels of L. arizonensis BCNU 9032 and L. brevis 9037 were demonstrated by bile salt hydrolytic activity and cholesterol assimilation tests. Moreover, L. brevis BCNU 9098 and BCNU 9101 showed higher adherence to Caco-2 cells (12.76 and 11.86%, respectively) than Lactobacillus rhamnosus GG, a commercial probiotic strain used worldwide. The results suggest that these strains could be used as probiotics.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.275-281
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• 2013

Probiotics have been reported to benefit human health by modulating immunity, lowering cholesterol, improving lactose tolerance, and preventing some cancer. Once ingested, probiotic microorganisms have to survive harsh conditions such as low pH, protease-rich condition, and bile salts during their passage through the gastro-intestinal (GI) tract colonize and proliferate to exert their probiotic effects. The dual coating technology, by which the bacteria are doubly coated with peptides and polysaccharides in consecutive order, was developed to protect the ingested bacteria from the harsh conditions. The aim of the study was to evaluate the viable stability of a doubly coated blend of four species of Bifidobacterium by comparing its bile/acid resistance and heat viability in vitro with that of the non-coated blend. After challenges with acid, bile salts, heat, and viable cell counts (VVCs) of the dual coated and non-coated blend were determined by cultivation on agar plates or flow cytometric measurement after being stain with the BacLigtht kit$^{TM}$. The results showed that the dual coated blend was much higher resistant to the acidic or bile salt condition than the non-coated blend and heat viability was also higher, indicating that the dual coating can improve the survival of probiotic bacteria during their transit through the GI tract after consumption.

• Korean Journal of Ichthyology
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• v.1 no.1_2
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• pp.42-53
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• 1989

The geographic variations of the number and morphology of scutes of eightspine stickleback, Pungitius sinensis, in the southern half of the Korean peninsula were investigated. The two subspecies, P. sinensis sinensis and P. sinensis kaibarae, showed a bit of difference in the number of scutes but there was no geocline as a whole. In the frequencies of individuals with the different number of scutes between the left and right body side, there was also difference between the two subspecies, and the specimens from the Hyongsan River showed great variation. The populations of Kumho River had the largest scutes. But the specimens of the Hyongsan River had small and degenerated scutes different from all other populations, and some individuals showed the semiarmatus type arrangement of scute. Therefore, this population may be called the special type of P. sinensis. In the relationship between the time of landlocking and the size of scutes, it was speculated that the population of the Hyongsan River was landlocked long years ago and other populations of P. sinensis kaibarae except the Kumho River were landlocked more recently. For the population of the Kumho River, however, it seemed that there was no relation between salt tolerance or landlocking and number or developmental state of scutes as this landlocked population had well developed and large number of scutes.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.597-604
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• 2014

$\small{D}$-Phenylglycine aminotransferase ($\small{D}$-PhgAT) from Pseudomonas stutzeri ST-201 is useful for enzymatic synthesis of enantiomerically pure $\small{D}$-phenylglycine. However, its low protein solubility prevents its application at high substrate concentration. With an aim to increase the protein solubility, the N-terminus of $\small{D}$-PhgAT was genetically fused with short peptides ($A_1$ ${\alpha}$-helix, $A_2$ ${\alpha}$-helix, and ALAL, which is a hybrid of $A_1$ and $A_2$) from a ferredoxin enzyme of a halophilic archaeon, Halobacterium salinarum. The fused enzymes $A_1$-$\small{D}$-PhgAT, $A_2$-$\small{D}$-PhgAT, and ALAL-$\small{D}$-PhgAT displayed a reduced pI and increased in solubility by 6.1-, 5.3-, and 8.1- fold in TEMP (pH 7.6) storage, respectively, and 5-, 4.5-, and 5.9-fold in CAPSO (pH 9.5) reaction buffers, respectively, compared with the wild-type enzyme (WT-$\small{D}$-PhgAT). In addition, all the fused $\small{D}$-PhgAT displayed higher enzymatic reaction rates than the WT-DPhgAT at all concentrations of L-glutamate monosodium salt used. The highest rate, $23.82{\pm}1.47$ mM/h, was that obtained from having ALAL-$\small{D}$-PhgAT reacted with 1,500 mM of the substrate. Moreover, the halophilic fusion significantly increased the tolerance of $\small{D}$-PhgAT in the presence of NaCl and KCl, being slightly in favor of KCl, where under the same condition at 3.5 M NaCl or KCl all halophilic-fused variants showed higher activity than WT-$\small{D}$-PhgAT.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.237-243
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• 2020

Listeria sp. is one of the pathogenic bacteria causes the infection listeriosis, through mainly raw food such as fishery food, dairy food and vegetables. Listeria sp. is a Gram-positive, non-spore-forming, motile, and facultative anaerobic bacterium. Because of the tolerance of Listeria sp. to low temperature and high salt concentration, it is very difficult to prevent them contaminated in the food, which do not require heating, especially, such as raw fishery products. So prevention and removal of bacterial contamination at the food manufacturing stage is the best method. In this study, therefore, several natural products including Psidium guajava and Geranium thunbergii were screened to investigate the antibacterial activity against Listeria sp., with expectation of fewer side effects and fewer resistance problems. Significant effects of two extracts were confirmed by well diffusion assay, MIC assay, and growth inhibition assay. P. guajava and G. thunbergii showed MIC values at 64-256 ㎍/mL meaning strong antibacterial activities against 6 kind of Listeria sp. tested. And the growth of Listeria sp. in the liquid media was actually inhibited by the addition of these two extracts.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.4
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• pp.307-313
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• 1992

To study the seasonal variation of heterotrophic bacteria near the surrounding seawater of Porphyra forming area, samples were collected in the intertidal waters of Mokp'o of the Yellow Sea from February to December, 1990. Annual distribution of heterotrophic bacteria ranged from $7.5\times10^2\;to\;1.1\times10^5\;cfu/ml,$ annual distribution of physiological characteristic bacteria ranged from $5.0\times10\;to\;4.34\times10^4\;cfu/ml$ for proteolytic bacteria, from 0 to $1.35\times10^4\;cfu/ml$ for lipolytic bacteria and from 0 to $1.2\times10^4\;cfu/ml$ for amylolytic bacteria. Sixty-five percent of isolates from seawater were rods, and $76.7\%$ of isolates were Gram-negative. Most isolates were mesophiles and showed utilization of various carbon sources such as glucose, maltose, lactose, sucrose and arabinose. Most isolates also showed tolerance to a broad range of salt concentration. Dominant genus in seawater were Flavobacterium spp., in February, Moraxella spp., Acinetobacter spp. in March, Bacillus spp., Chromobacterium spp., Micrococcus spp., Vibrio spp. in July and Chromobacterium spp., Micrococcus spp., Bacillus spp. in November.

• Journal of Life Science
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• v.30 no.10
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• pp.896-904
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• 2020

The purpose of this study was to investigate the probiotic characteristics and immune activities of selected lactic acid bacterial (LAB) strains as feed additives in livestock. 301 LAB strains isolated from traditional fermented foods were first assessed for their antibacterial activity potential. Of the 301 isolates, five showed antibacterial activity against five livestock pathogens (Esherichia coli KCCM11234, Listeria monocytogens KCTC3710, Salmonella Typhimurium KCTC1926, Staphylococcus aureus KCCM11593, and Shigella flexneri KCTC2517). The probiotic characteristics of the five selected strains were also investigated by antioxidative activity, hemolysis, bile salt hydrolase, acid resistance and bile tolerance. The SRCM102607 strain was found to have superior probiotic properties and was selected for further experimentation. 16S rRNA gene sequencing showed that SRCM102607 is Pediococcus acidilactici, which was labeled as P. acidilactici SRCM102607 (KCCM 12246P). The survival characteristics of P. acidilactici SRCM102607 in artificial gastrointestinal conditions were assessed under exposed acidic (pH 2.0) and bile (0.5% and 1.0%) conditions. P. acidilactici SRCM102607 was also confirmed to have resistance to various antibiotics, including amikacin, gentamicin, vancomycin, and etc. The TNF-α production by P. acidilactici SRCM102607 was 171.86±4.00 ng/ml. These results show that P. acidilactici RCM102607 has excellent potential for use as a probiotic livestock feed additive.