• Fisheries and Aquatic Sciences
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• 제27권6호
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• pp.379-391
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• 2024

Tocopherol, carotenoids, and chlorophyll are the primary components of the antioxidative response in microalgae. Conditions of stress, such salt stress, can trigger the processes responsible for the accumulation of tocopherol and carotene. It has been found that the most difficult part of culturing microalgae is keeping it affordable. This study investigated the effects of different salt types and concentrations on the amount of α-tocopherol, carotenoid derivatives, and flocculation efficiency of Euglena sp. Cultures of Euglena sp. was developed under salt stress conditions of NaCl 200 mM and KCl 200 mM. UV-VIS spectrophotometry was used to confirm the presence of α-tocopherol and carotenoid derivatives under thirteen days of salt stress testing. Increasing salinity has a significant effect on Euglena sp., causing spherical cell morphologies with aspect ratio 1.385 ± 0.031 for NaCl 200 mM and 1.414 ± 0.040 for KCl 200 mM. Increasing salinity also slowing down development with specific growth rate value of 0.171 ± 0.006 per day and 0.122 ± 0.029 per day for NaCl and KCl 200 mM, respectively. Nevertheless, the amount of α-tocopherol in Euglena sp. increases with a high salt concentration; algal cells flocculated more successfully when increasing the salt concentrations (NaCl 200 mM and KCl 200 mM) was added. Due to the inhibition of photosynthetic activity in salt-stressed cells, the control group exhibited higher levels of carotenoid derivatives (ranging from 0.5-1 ㎍/mL) and pheophytin a and b (0.0062 ± 0.001 ㎍/mL and 0.0064 ± 0.001 ㎍/mL) than the group treated with salt stress. In conclusion, salt stress was an effective way to raises the concentration of α-tocopherol and significantly reduce the expense of harvesting Euglena sp.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2020년도 추계학술대회
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• pp.127-127
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• 2020

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.188-188
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• 2017

Rice (Oryza sativa L.) is one of the major crops that is seriously impacted by global soil salinization. Rice is among those crops where most of the high-yielding cultivars are highly sensitive to salinity. The key to a plant survival under NaCl salt stress is by maintaining a high $K^+/Na^+$ ratio in its cells. Selection for salinity tolerance genotypes of rice based on phenotypic performance alone is less reliable and will delay in progress in breeding. Recent advent of molecular markers, microsatellites or simple sequence repeats (SSRs) were used to find out salt tolerant rice genotypes. In the current experiment phenotyping and genotyping studies were correlated to differentiate different rice accessions for salinity tolerance. Eight rice accessions along with check plant Dongjin were screened by physiological studies using Yoshida solution with 50mM NaCl stress condition. The physiology studies identified four tolerant and four susceptible accessions based on their potassium concentration, sodium concentration, $K^+/Na^+$ ratio and biomass. 17 SSR markers were used to evaluate these rice accessions for salt tolerance out of which five molecular markers were able to discriminate tolerant accessions from the susceptible accessions. Banding pattern of the accessions was scored comparing to the banding pattern of Dongjin. The study identifies accessions based on their association of $K^+/Na^+$ ratio with molecular markers which is very reliable. These markers identified can play a significant role in screening large set of rice accessions for salt tolerance; these markers can be utilized to improve salt tolerance of commercial rice varieties with marker-assisted selection (MAS) approach.

• Animal cells and systems
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• 제14권1호
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• pp.17-23
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• 2010

We isolated warm temperature acclimation-related protein 65-kDa (Wap65) cDNA from the liver of olive flounder and investigated the mRNA expression of Wap65 and HSP70 in olive flounder exposed to osmotic (17.5, 8.75, and 4 psu) and thermal stress (25 and $30^{\circ}C$). The mRNA expression of Wap65 and HSP70 was increased by thermal stress. The mRNA expression of HSP70 was also increased by osmotic stress, whereas no significant change in Wap65 expression was detected. These results indicate that Wap65 mRNA expression occurs specifically in response to increases in water temperature, but not in response to osmotic stress. Plasma cortisol levels were also increased by osmotic and thermal stress. We also utilized the stress hormone cortisol to examine whether Wap65 expression is thermal-stress-specific. Cortisol treatment increased HSP70 mRNA expression in vitro, but had no significant effect on Wap65 mRNA expression. Thus, thermal stress, but not osmotic stress, induces Wap65 expression.

• 환경생물
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• 제24권4호
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• pp.380-386
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• 2006

30일 동안 15 psu에서 순화 사육한 양식 넙치(평균전장: 20.8cm,평균체중: 96.1g)를 사용하여 염분변화에 따른 혈액 학적 변화 (cortisol, glucose, $Na^+$, $Cl^-$, $K^+$, AST, ALT, hematocrit, RBC, hemoglobin) 및 생존율을 조사하였다. 사육수를 실험개시시 15 psu로부터 0 psu(group I, G I)와 35 psu(group II, G II)로 30분 이내에 교환하였다. 5일 동안 유지하였으며, 다시 사육수를 0 psu로부터 35 psu(G I)와 35 psu에서 0 psu(G II)로 교환하였다. G I구는 cortisol, glucose, $Na^+$, $Cl^-$, AST및 생존율 등에서 일반적인 stress 경향을 보였다. G II구는 35 psu에서 0 psu로 교환한 240시간째에 cortisol, glucose 및 AST에서 유의적으로 높아진 값을 보였다. 두 실험구에서 생존율은 35 psu에서보다 0 psu에서 낮아지는 것으로 나타났다. 본 연구 결과 고염분과 저 염분변화에 따른 cortisol, glucose, $Na^+$, $K^+$, $Cl^-$및 생존율에 대한 기초자료로 유용할 것이다.

• 한국어류학회지
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• 제22권1호
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• pp.17-24
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• 2010

본 연구에서는 감성돔의 염분과 수온 변화에 따른 스트레스 반응을 알아보기 위하여 glucocorticoid receptor (GR) mRNA 발현을 조사하였다. 감성돔 신장으로부터 전장의 GR cDNA를 클로닝하였고, 염분과 수온이 변화하는 동안 아가미, 신장 및 장에서 GR mRNA 발현 변화를 quantitative real-time PCR (QPCR)을 이용하여 조사하였다. 염분 변화시, 아가미, 신장 및 장에서 GR mRNA 발현은 0 psu에서 가장 높게 나타났으며, 혈장 cortisol과 glucose 농도도 증가한 반면, triiodothyronine ($T_3$) 농도는 감소하였다. 수온 변화시, 아가미, 신장 및 장에서 GR mRNA 발현은 $30^{\circ}C$에서 가장 높게 관찰되었다. 혈장 cortisol, glucose 및 $T_3$ 농도 또한 고수온 ($30^{\circ}C$)에서 증가하였다. GR mRNA 발현의 증가는 염분과 수온 변화와 같은 환경 요인에 대한 좋은 스트레스 지표로 여겨진다.

• Molecules and Cells
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• 제37권2호
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• pp.109-117
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• 2014

Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways.

• 한국패류학회지
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• 제29권3호
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• pp.181-187
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• 2013

In order to investigate environmental stress inducible genes in abalone, we analyzed differentially expressed transcripts from a Pacific abalone, Haliotis discus hannai, after exposure to heat-, cold- or hyposalinity-shock by suppression subtractive hybridization (SSH) method. 1,074 unique sequences from SSH libraries were composed to 115 clusters and 986 singletons, the overall redundancy of the library was 16.3%. From the BLAST search, of the 1,316 ESTs, 998 ESTs (75.8%) were identified as known genes, but 318 clones (24.2%) did not match to any previously described genes. From the comparison results of ESTs pattern of three SSH cDNA libraries, the most abundant EST was different in each SSH library: small heat shock protein p26 (sHSP26) in heat-shock, trypsinogen 2 in cold-shock, and actin in hyposalinity SSH cDNA library. Based on sequence similarities, several response-to-stress genes such as heat shock proteins (HSPs) were identified commonly from the abalone SSH libraries. HSP70 gene was induced by environmental stress regardless of temperature-shock or salinity-stress, while the increase of sHSP26 mRNA expression was not detected in cold-shock but in heat-shock condition. These results suggest that the suppression subtractive hybridization method is an efficient way to isolate differentially expressed gene from the invertebrate environmental stress-response transcriptome.

• Journal of Plant Biotechnology
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• 제46권2호
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• pp.97-105
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• 2019

Dehydration Responsive Element Binding (DREB) gene is one of the essential transcription factors plants use for responding to stress conditions including salinity, drought, and cold stress. The purpose of this study was to isolate the full length and characterize the DREB gene from three different genotypes of sugarcane, wild, commercial cultivar, and interspecific hybrid sugarcane. The length of the gene, designated ScDREB was 789 bp, and coding for a putative polypeptide of 262 amino acid residues. Sequences of the gene were submitted to the GenBank database with accession numbers of KX280722.1, KX280721.1, and KX280719.1 for wild sugarcane, commercial cultivar (KPS94-13), and interspecific hybrid (Biotec2), respectively. In silico characterization indicated that the deduced polypeptide contains a putative nuclear localization signal (NLS) sequence, and a conserved AP2/ERF domain of the DREB family, at 82-140 amino residues. Based on multiple sequence alignment, sequences of the gene from the three sugarcane genotypes were classified in the DREB2 group. Gene expression analysis indicated, that ScDREB2 expression pattern in tested sugarcane was up-regulated by salt stress. When the plants were under 100 mM NaCl stress, relative expressions of the gene in leaves was higher than those in roots. In contrast, under 200 mM NaCl stress, relative expressions of the gene in roots was higher than those in leaves. This is the first report on cloning the full length and characterization, of ScDREB2 gene of sugarcane. Results indicate that ScDREB2 is highly responsive to salt stress.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.284-284
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• 2022

The overall effects of gibberellic acid (GA3) with NaCl on different rice genotypes are inadequately understood. The present study determines the effect of different GA3 concentrations on the morphophysiological, molecular and biochemical effects of 120 mM NaCl salt stress in rice seedlings. Salt stress reduced germination percentages and seedling growth and decreased bioactive GA content. It also downregulated the relative expression of a-amylase-related genes - OsAmy1A, OsAmy1C, and OsAmy3C in the salt-sensitive IR28 cultivar. Salt stress differentially regulated the expression of GA biosynthetic genes. Salt stress increased antioxidant activity in all rice genotypes tested, except in IR28. GA3 (50 and 100 µM) mitigates the effect of salt stress, rescuing seed germination and growth attributes. GA3 significantly increased bioactive GA content in Nagdong and pokkali (50 µM) and Cheongcheong and IR28 (100 µM) cultivars. The a-amylase genes were also significantly upregulated by GA3. Similarly, GA3 upregulated OsGA2oxl and OsGA2ox9 expression in the Cheongcheong and salt-sensitive IR28 cultivars. The present study demonstrated that salt stress inactivates bioactive GA - inhibiting germination and seedlings growth - and decreases bioactive GA content and GSH activity in IR28 and Pokkali cultivars. Further, GA3 significantly reversed the effects of 120 mM NaCl salt stress in different rice genotypes. The current study also suggests if we know the coastal area water NaCl concentration we can apply the exogenous GA3 accordingly. Thus, we would be able to grow rice cultivars near the coastal area and reduce the rice damage by salinity.