• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.15-22
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• 2008

Four series (S, M, R, and W) of Alternaria longipes isolates were obtained based on consecutive selection with Dimethachlon (Dim) and ultraviolet irradiation. These isolates were then characterized according to their tolerance to Dim, sensitivity to osmotic stress, and phenotypic properties. All the selected Dim-resistant isolates showed a higher osmosensitivity than the parental strains, and the last generation was more resistant than the first generation in the M, R, and W series. In addition, the changes in the Dim resistance and osmotic sensitivity were not found to be directly correlated, and no distinct morphologic characteristics were found among the resistant and sensitive isolates, with the exception of the resistant isolate K-11. Thus, to investigate the molecular basis of the fungicide resistance, a group III two-component histidine kinase (HK) gene, AlHK1, was cloned from nineteen A. longipes isolates. AlHK1p was found to be comprised of a six 92-amino-acid repeat domain (AARD), HK domain, and response regulator domain, similar to the Os-1p from Neurospora crassa. A comparison of the nucleotide sequences of the AlHK1 gene from the Dim-sensitive and -resistant isolates revealed that all the resistant isolates contained a single-point mutation in the AARD of AlHK1p, with the exception of isolate K-11, where the AlHK1p contained a deletion of 107 amino acids. Moreover, the AlHK1p mutations in the isolates of each respective series involved the same amino acid substitution at the same site, although the resistance levels differed significantly in each series. Therefore, these findings suggested that a mutation in the AARD of AlHK1p was not the sole factor responsible for A. longipes resistance to dicarboximide fungicides.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.318-326
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• 2002

The pathogenic marine bacterium Vibrio vulnificus is the causative agent of food-borne diseases such as life-threatening septicemia. To better understand this organism's strategies to survive osmotic stress, a mutant that was more sensitive to high osmolarity was screened from a library of mutants constructed by a random transposon mutagenesis. By a transposon-tagging method, putAP genes encoding a proline dehydrogenase and a proline permease were identified and cloned from V. vulnificus. The amino acid sequences deduced from nucleotide sequences of putAP from V. vulnificus were 38 to $59\%$ similar to those of PutA and PutP reported from other Enterobacteriaceae. Functions of putAP genes were assessed by the construction of mutants, whose putAP genes were inactivated by allelic exchanges. When proline as the sole carbon or nitrogen source was used, the putA mutant was not able to grow to the substantial level, revealing the proline dehydrogenase is the only enzyme for metabolic conversion of proline into other amino acids. Although the growth rate of the putP mutant on proline as the sole carbon or nitrogen source was significantly reduced, the mutant still grew. This indicated that at least one more proline permease is produced by V. vulnificus. The putP mutant decreased approximately $2-log_10$ CFU/ml after a hyperosmotic challenge, while the parent strain decreased approximately $l-log_10$ CFU/ml. This result suggests that the gene product of putP contributes to the osmotic tolerance of V. vulnificus.

• Journal of Embryo Transfer
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• v.33 no.4
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• pp.221-228
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• 2018

The osmolarity of a medium that is commonly used for in vitro culture (IVC) of oocytes and embryos is lower than that of oviductal fluid in pigs. In vivo oocytes and embryos can resist high osmolarities to some extent due to the presence of organic osmolytes such as glycine and alanine. These amino acids act as a protective shield to maintain the shape and viability in high osmotic environments. The aim of this study was to determine the effects of glycine or/and alanine in medium with two different osmolarities (280 and 320 mOsm) during IVC on embryonic development after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) in pigs. To this end, IVC was divided into two stages; the 0-2 and 3-7 days of IVC. In each stage, embryos were cultured in medium with 280, 320, or 360 mOsm and their combinations with or without glycine or/and alanine according to the experimental design. Treatment groups were termed as, for example, "T(osmolarity of a medium used in 0-2 days of IVC)-(osmolarity of a medium used in 3-7 days of IVC)" T280-280 was served as control. When PA embryos were cultured in medium with various osmolarities, T320-280 showed a significantly higher blastocyst formation (29.0%) than control (22.2%) and T360-360 groups (6.9%). Glycine treatment in T320-280 significantly increased blastocyst formation (50.4%) compared to T320-280 only (36.5%) while no synergistic was observed after treatment with glycine and alanine together in T320-280 (45.7%). In contrast to PA embryonic development, the stimulating effect by the culture in T320-280 was not observed in SCNT blastocyst development (27.6% and 23.7% in T280-280 and T320-280, respectively) whereas the number of inner cell mass cells was significantly increased in T320-280 (6.1 cells vs. 9.6 cells). Glycine treatment significantly improved blastocyst formation of SCNT embryos in both T280-280 (27.6% vs. 38.0%) and T320-280 (23.7% vs. 35.3%). Our results demonstrate that IVC in T320-280 and treatment with glycine improves blastocyst formation of PA and SCNT embryos in pigs.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.2
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• pp.114-119
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• 2014

Salinity and drought stresses are probably the most significant abiotic factor limiting plant's growth, also negatively affect seed germination and early seedling development. To study on effect of NaCl and PEG stress on seed germination and gene expression pattern of tall fescue, the levels of NaCl and PEG-induced water stresses were determined in first experiment. Different concentration of NaCl (0 to 350 mM) and PEG (0 to 30%) were used for seed treatment. Seed Germination percentage reduced with increasing osmotic potential of growth medium either due to NaCl or PEG. Seeds were not germinate at 350 mM NaCl or 30% PEG treatment. On the basis of the results, Kentucky31(E-) had more resistant than Fawn in both stress conditions. Furthermore, we have used an annealing control primer-based differential display reverse transcription-polymerase chain reaction method to identify salt- and drought stress-induced differentially expressed genes (DEGs) in tall fescue leaves. Using 120 annealing control primers, a total of 4 genes were identified and sequenced. The possible roles of the identified DEGs are discussed in the context of their putative role during salinity and drought stresses.

• Journal of Life Science
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• v.22 no.10
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• pp.1359-1370
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• 2012

Arabidopsis AtERF71/HRE2, a transcription activator, is located in the nucleus and is involved in the signal transduction of low oxygen and osmotic stresses. In this study, microarray analysis using AtERF71/HRE2-overexpressing transgenic plants was performed to identify genes downstream of AtERF71/HRE2. A total of 161 different genes as well as AtERF71/HRE2 showed more than a twofold higher expression in AtERF71/HRE2-overexpressing transgenic plants compared with wild-type plants. Among the 161 genes, 24 genes were transcriptional regulators, such as transcription factors and DNA-binding proteins, based on gene ontology annotations, suggesting that AtERF71/HRE2 is an upstream transcription factor that regulates the activities of various downstream genes via these transcription regulators. RT-PCR analysis of 15 genes selected out of the 161 genes showed higher expression in AtERF71/HRE2-overexpressing transgenic plants, validating the microarray data. On the basis of Genevestigator database analysis, 51 genes among the 161 genes were highly expressed under low oxygen and/or osmotic stresses. RT-PCR analysis showed that the expression levels of three genes among the selected 15 genes increased under low oxygen stress and another three genes increased under high salt stress, suggesting that these genes might be downstream genes of AtERF71/HRE2 in low oxygen or high salt stress signal transduction. Microarray analysis results indicated that AtERF71/HRE2 might also be involved in the responses to other abiotic stresses and also in the regulation of plant developmental processes.

• Journal of Life Science
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• v.28 no.9
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• pp.1030-1041
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• 2018

Abiotic stresses limit the growth and productivity of plants. Cellular adaptation to abiotic stresses requires coordinated regulation in gene expression directed by complex mechanisms. This study used the activation tagging system to identify novel salt stress-responsive genes. The study selected 9 activation tagging lines that showed salt stress-tolerant phenotypes during their germination stages. Thermal asymmetric interlaced-PCR (TAIL-PCR) was used to identify the T-DNA tagging sites on the Arabidopsis genome in selected activation tagging lines, including AT7508, AT7512, AT7527, AT7544, AT7548, and AT7556. RT-PCR analysis showed that ClpC2/HSP93-III (At3g48870), plant thionin family (At2g20605), anti-muellerian hormone type-2 receptor (At3g50685), vacuolar iron transporter family protein (At4g27870), and microtubule-associated protein (At5g16730) were activated in AT7508, AT7512, AT7527, AT7544, and AT7556, respectively. Interestingly, in AT7548, both the genes adjacent to the T-DNA insertion site were activated: Arabinogalactan protein 13 (AGP13) (At4g26320) and F-box/RNI-like/FBD-like domains-containing protein (At4g26340). All of the seven genes were newly identified as salt stress-responsive genes from this study. Among them, the expression of ClpC2/HSP93-III, AGP13, F-box/RNI-like/FBD-like domains-containing protein gene, and microtubule-associated protein gene were increased under salt-stress condition. In addition, AT7508, AT7527, and AT7544 were more tolerant to salt stress than wild type at seedling development stage, functionally validating the screening results of the activation tagging lines. Taken together, our results demonstrate that the activation tagging system is useful for identifying novel stress-responsive genes.

• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.17-24
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• 2010

The present study investigated the expression of glucocorticoid receptor (GR) mRNA as a stress response during salinity changes (35, 10, and 0 psu) and water temperature changes (from $20^{\circ}C$ to $30^{\circ}C$, $1^{\circ}C$/day) in black porgy. We cloned the full-length GR cDNA from the kidney and examined its expression in the gill, kidney, and intestine by quantitative real-time PCR (QPCR) during salinity and water temperature changes. During salinity changes, the levels of GR mRNA in the gill, kidney, and intestine were highest at 0 psu, and the levels of plasma cortisol and glucose were elevated, but triiodothyronine ($T_3$) decreased. Also, during water temperature changes, the levels of GR mRNA in the gill, kidney, and intestine increased at $30^{\circ}C$. Plasma parameters also increased with an increase in water temperature. Therefore, this upregulation of GR mRNA was a good indicator of stress, such as those resulting from changes in salinity and water temperature.

• 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.

• Journal of Embryo Transfer
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• v.33 no.2
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• pp.75-84
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• 2018

The cryopreservation has been extensively applied in many cells including spermatozoa (semen) during past several decades. Especially, the canine spermatozoa cryopreservation has contributed on generation of progeny of rare/genetically valuable dog breeds, genome resource banking and transportation of male germplasm at a distant place. However, severe and irreversible damages to the spermatozoa during cryopreservation procedures such as the thermal shock (cold shock), formation of intracellular ice crystals, osmotic shock, stress of cryoprotectants and generator of reactive oxygen species (ROS) have been addressed. According as a number of researches have been conducted to overcome these problems and to advance cryopreservation technique, several analytical methods have been employed to evaluate the quality of the fresh or cryopreserved canine spermatozoa in regards to the motility, morphology, integrity of membrane and DNA, mitochondrial activity, ROS generation, binding affinity to oocytes, in vitro fertilization potential and fertility potential by artificial insemination. Because the study designs with certain application of analytical methods are selective and varied depending on each experimental objective and laboratory condition, it is necessary to establish the normal reference data of the fresh or cryopreserved canine spermatozoa for each analytical method to monitor experimental procedure, to translate raw data and to discuss results. Here, we reviewed the recent articles to introduce various analytical methods for the canine spermatozoa as well as to establish the normal reference data for each analytical method in the fresh or cryopreserved canine spermatozoa, based on the results of the previous articles. We hope that this review contributes to the advancement of cryobiology in canine spermatozoa.

• The Korean Journal of Zoology
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• v.38 no.4
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• pp.570-579
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• 1995

Ultrastructural and histochemical changes of mucous cells In the freshwater and seawater-adapted guppy (Poecflia reticulatus) gills were observed by the light, scanning-and transmisslon~lectron microscopes. The mucous cells were usually located in the epithelium of primary lameilne projected from the gill arch. The rough endoplasmic retIculum and Golgi complex were hIghly developed In immature mucous cells. The mature mucous cells were nearly filled with the mucous granules. In the freshwater guppy, the histochemical properties of the mucous cells were a mixture of the neutral mucin, sialomucin and sulfomucin. When guppy was adapted to the seawater, the content of acid glycoproteins (slalomucln and sulfomucin) was decreased. In addition, the number of mucous cells in the seawater-adapted group was less than a third of those in the freshwater one. These results suggest that the seawater-adapted guppy would react to the changed osmotic stress of the seawater. And also, the environmental change by the increased salt concentraion might lead to reduce the chance of infections.