• Journal of Ecology and Environment
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• v.39 no.1
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• pp.81-90
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• 2016

This study was to investigate the effect of salt stress on physiological characteristics such as plant growth, photosynthesis, solutes related to osmoregulation of Beta vulgaris. A significant increase of dry weight was observed in 50 mM and 100 mM NaCl. The contents of Chl a, b and carotenoid were lower in NaCl treatments than the control. On 14 day after NaCl treatment, photosynthetic rate (P_N), the transpiration rate (E) and stomatal conductance of CO₂ (g_s) were reduced by NaCl treatment. On 28 day after NaCl treatment, the significant reduction in g_s and E was shown in NaCl 200 mM. However, P_N and water use efficiency (WUE) in all NaCl treatments showed higher value than that of control. Total ion contents (TIC) and osmolality were higher than the control. On 14 day after treatment, the contents of proline (Pro) increased significantly in 200 mM and 300 mM NaCl concentration compared with control, whereas on 28 day in all treatments it was lower than that of the control. The contents of glycine betaine (GB) increased with the increase of NaCl concentration. The contents of Na⁺, Cl^-, GB, osmolality and TIC increased with the increase of NaCl concentrations. These results suggested that under severe NaCl stress conditions, NaCl treatment did not induce photochemical inhibition on fluorescence in the leaves of B. vulgaris, but the reduction of chlorophyll contents was related in a decrease in leaf production. Furthermore, increased GB as well as Na⁺ and Cl^- contents resulted in a increase of osmolality, which can help to overcome NaCl stress.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.1
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• pp.16-21
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• 2024

Green manure crops have a variety of benefits, including improving soil fertility, removing soil salinity, enhancing soil aeration and moisture regulation, reducing the use of chemical fertilizers, reducing nitrous oxide emissions, reducing herbicide use through weed-suppressive effects, promoting agricultural ecosystem protection and carbon dioxide absorption capacity. To find ways to increase the germination rate of legumes and green manure crop seeds, which are imported in large quantities every year. It was carried out that two seed priming methods, osmotic priming and heat treatment, and compared their effects. Heat treatment was treated for 10 minutes at 40℃ or 60℃, followed by rinsing with water. Osmotic priming was applied for 30 seconds in a saline solution with a specific gravity of 1.13. Overall, there was no significant difference in the final germination rate, but it was found that osmotic priming and heat treatment affected the germination speed. However, applying heat treatment and osmotic priming simultaneously did not affect the germination characteristics. Therefore, it is suggested that heat treatment and osmotic priming can increase the germination speed of soybean and green manure crops.

• Animal cells and systems
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• v.16 no.5
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• pp.391-399
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• 2012

We cloned cDNA-encoding arginine vasotocin (AVT) from the brain of the cinnamon clownfish Amphiprion melanopus, and that was predicted to encode a protein of 153 amino acids. We examined changes in the expression of AVT mRNA in the brain and arginine vasotocin receptor (AVTR) mRNA and osmotic stress transcription factor 1 (OSTF1) mRNA in the gills of the cinnamon clownfish using quantitative real-time PCR in an osmotically changing environment (seawater (35 psu) ${\rightarrow}$ brackish water (BW, 17.5 psu) and BW with prolactin [PRL]). The expression of AVT, AVTR, and OSTF1 mRNA in the brain and gills increased after transfer to BW, and the expression was repressed by PRL treatment. AVT-immunoreactive cells were almost consistently observed in the telencephalon. The plasma $Na^+$ and $Cl^-$ levels decreased in BW, but the level of this parameter increased in BW with PRL treatme during salinity change. These results suggest that AVT, AVTR, and OSTF1 play important roles in hormonal regulation in osmoregulation organs, and that PRL improves the hyperosmoregulatory ability of cinnamon clownfish in BW environment.

• Korean Journal of Environmental Biology
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• v.34 no.2
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• pp.97-106
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• 2016

$Na^+/K^+$-ATPase is a membrane protein and plays a key role in osmotic regulation in living organisms. In the present study, a cDNA sequence encoding the $Na^+/K^+$-ATPase alpha subunit from the monogonont rotifer, Brachionus koreanus was cloned by rapid amplification of cDNA ends technique. To investigate the role of this enzyme in osmotic stress, enzymatic activities of $Na^+/K^+$-ATPase were measured after exposure to different salinities for 48 h. The full-length Bk $Na^+/K^+$-ATPase cDNA was 3069 bp-long, encoding a 1022-amino acid polypeptide. Bk $Na^+/K^+$-ATPase possesses eight membrane spanning regions and five conserved domains. Phylogenetic analysis showed that Bk $Na^+/K^+$-ATPase had high identity with those of other species, and was closely clustered with other Brachionus sp. These findings indicate that this protein was conserved both structurally and functionally. B. koreanus $Na^+/K^+$-ATPase activity was stimulated in both hyposaline (6 psu) and hypersaline (32 psu) conditions, suggesting that this protein may play a role in osmoregulation. This study would provide better understanding of the physiology of B. koreanus and this enzyme may be useful as a molecular marker for evaluation of osmotic stress in aquatic environment.

• Molecules and Cells
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• v.20 no.1
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• pp.43-50
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• 2005

Glutaredoxin (Grx) is a small, heat-stable redox protein acting as a multi-functional glutathione (GSH)-dependent disulfide oxidoreductase. We have cloned the monothiol Grx5 gene from the genomic DNA of the fission yeast Schizosaccharomyces pombe. It has 1,904 bp, with one intron, and encodes a putative protein of 146 amino acids with a molecular mass of 16.5 kDa. Recombinant Grx5 produced functional Grx in S. pombe cells. NO-generating sodium nitroprusside (SNP, 1.0 and 2.0 mM) and potassium chloride (KCl, 0.2 and 0.5 M) increased the synthesis of ${\beta}$-galactosidase from a Grx5-lacZ fusion gene, and transcription of Grx5 was also enhanced by SNP and KCl. Synthesis of ${\beta}$-galactosidase from the Grx5-lacZ fusion was lower in Pap1-negative TP108-3C cells than in wild type KP1 cells, and when Pap1 was overproduced in KP1 cells, the level of ${\beta}$-galactosidase increased. We also found that Pap1 is involved in the induction of Grx5 by SNP and KCl. S. pombe Grx5 may play a crucial role in responses to nitrosative and osmotic stresses.

• BMB Reports
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• v.42 no.1
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• pp.28-34
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• 2009

To understand the molecular mechanism underlying proline accumulation in Brassica napus, cDNAs encoding ${\Delta}^1$-pyrroline-5-carboxylate synthetase (BnP5CS), ornithine $\delta$-aminotransferase (BnOAT) and proline dehydrogenase (BnPDH) were isolated and characterized. Southern blot analysis of BnP5CSs in B. napus and its diploid ancestors suggested a gene loss may have occurred during evolution. The expression of BnP5CS1 and BnP5CS2 was induced, while the expression of BnPDH was inhibited under salt stress, ABA treatment and dehydration, prior to proline accumulation. The upregulation of BnOAT expression was only detected during prolonged severe osmotic stress. Our results indicate that stress-induced proline accumulation in B. napus results from the reciprocal action of activated biosynthesis and inhibited proline degradation. Whether the ornithine pathway is activated depends on the severity of stress. During development, proline content was high in reproductive organs and was accompanied by markedly high expression of BnP5CS and BnPDH, suggesting possible roles of proline during flower development.

• The Korean Journal of Ecology
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• v.21 no.1
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• pp.89-96
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• 1998

The diurnal changes of the stomatal conductance, transpiration and leaf water potential were measured in order to assess the water relations characteristics of Pueraria thunbergiana in August of 1995 and 1996. The results showed two different responses depending on the duration of rainless days. The microclimatic conditions were highly stressful on 2 August. Daily maximum temperature reached to $39.0{\circ}C$ and vapor pressure deficit was 3.55 KPa. During this time the leaf water potential decreased to -1.02 MPa and a marked reduction of stomatal conductance was shown. However, on 15 August the stomatal conductance increased with increment of photon flux density, and transpiration was highly maintained during the day time. Minimum leaf water potential was only -0.47 MPa in spite of high transpiration rate. Furthermore, on 15 August reduced leaf water potential during the day time was recovered rapidly with decrease of photon flux density, whereas recovery of leaf water potential on 2 August was delayed. However, reduced leaf water potential on 2 August was recovered untile the next dawn. Osmotic potential at turgor loss point of Pueraria thunbergiana on 2, 3 and 15 August was -1.79, -1.70 and -1.60 MPa, respectively. The vapor pressure deficit is more contributive to the regulation of stomatal conductance than leaf water potential.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.676-684
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• 2021

Euryhaline teleost have extraordinary ability to deal with a wide range of salinity changes. To study the seawater adaptability of rainbow trout Oncorhynchus mykiss (body weight 638±54 g, length 38.6±2 cm) to salinity increase fish were transferred from freshwater to 7, 14, 21, 28 and 32 psu and checked for mortality over 5 days. No mortality was observed in 0-32 psu. In fish transferred to 0-32 psu, blood osmolality was maintained within physiological range. The changes of serum enzyme activities (aspartate transaminase, AST and alanine transaminase, ALT) showed no significant level during experimental period. To explore the underlying molecular physiology of gill and kidney responsible for body fluid regulation, we measured mRNA expression of five genes, Na⁺/K⁺/2Cl^- cotransporter1 (NKCC1), aquaporin3 (AQP3), cystic fibrosis transmembrane conductance regulator (CFTR), glucocorticoid receptor (GR) and growth hormone receptor (GHR) in response to salt stress. Based on our result, rainbow trout could tolerate gradual transfer up to 32 psu for 5 days without mortality under physiological stress. This study suggests to alleviate osmotic stress to fish, a gradually acclimation to increasing salinity is recommended.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.119-130
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• 1996

We review the factors which regulate the depth and composition of the human airway surface liquid (ASL). These include secretion from airway submucosal glands, ion and fluid transport across the surface epithelium, goblet cell discharge, surface tension and transepithelial gradients in osmotic and hydrostatic pressure. We describe recent experiments in which we have used low temperature scanning electron microscopy of rapidly frozen specimens to detect changes in depth of ASL in response to submucosal gland stimulation. We also present preliminary data in which X-ray microanalysis of frozen specimens has been used to determine the elemental composition of ASL.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.503-508
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• 2014

Spontaneous myometrial contraction (SMC) in pregnant uterus is greatly related with gestational age and growing in frequency and amplitude toward the end of gestation to initiate labor. But, an accurate mechanism has not been elucidated. In human and rat uterus, all TRPCs except TRPC2 are expressed in pregnant myometrium and among them, TRPC4 are predominant throughout gestation, suggesting a possible role in regulation of SMC. Therefore, we investigated whether the TRP channel may be involved SMC evoked by mechanical stretch in pregnant myometrial strips of rat using isometric tension measurement and patch-clamp technique. In the present results, hypoosmotic cell swelling activated a potent outward rectifying current in G protein-dependent manner in rat pregnant myocyte. The current was significantly potentiated by $1{\mu}M$ lanthanides (a potent TRPC4/5 stimulator) and suppressed by $10{\mu}M$ 2-APB (TRPC4-7 inhibitor). In addition, in isometric tension experiment, SMC which was evoked by passive stretch was greatly potentiated by lanthanide ($1{\mu}M$) and suppressed by 2-APB ($10{\mu}M$), suggesting a possible involvement of TRPC4/5 channel in regulation of SMC in pregnant myometrium. These results provide a possible cellular mechanism for regulation of SMC during pregnancy and provide basic information for developing a new agent for treatment of premature labor.