• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.1-15
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• 1995

Tolerance to toxic effects of cadmium(Cd), including lethality has been shown following pretreatment with cadmium and zinc. This study was designed to determine if tolerance also develops to Cd-induced hepatotoxicity and renal toxicity. Three groups of rats(A, B, C), each consisting of 52 rats, were studied and each group was divided into three subgroups(1,2,3), 28 rats for each subgroup. Rats were subcutaneously pretreated with saline(A), $CdCl_2$(0.5 mg/kg, B), and $ZnCl_2$(13.0 mg/kg, C) during time periods of 5 days. At the end of the period, rats were challenged with $CdCl_2$(3.0 and 6.0 mg/kg) by intraperitoneal injection. As for the cadmium levels in rat tissues after 1,3,5,6 days of pretreatments, it was highest in the liver. Then kidney, heart, blood and muscle followed it in that order. After 24, 48 and 96 hours of intraperitoneal injection by challenge doses the concentration of cadmium in liver and kidney increased proportionally to the increase of challenge dosage. However metallothioneins in liver and kidney were increased by the pretreatment of cadmium and zinc. These data indicate the liver is a major target-organ of acute Cd poisoning, and suggest that cadmium induced hepatic injury, via release of Cd-MT, may play an important role in the nephrotoxicity observed in response to short-term exposure to cadmium. This result suggest that increasing cadmium concentrations, gradually accumulating in liver and kidney as the result of the pretreatment, served to induce the synthesis of metallothionein, thus making them resistant to the challenge from cadmium.

• Molecules and Cells
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• v.27 no.1
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• pp.15-19
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• 2009

Notch signaling is controlled at multiple levels. In particular, stabilized Notch receptor activation directly affects the transcriptional activations of Notch target genes. Although some progress has been made in terms of defining the regulatory mechanism that alters Notch stability, it has not been determined whether Notch1/NICD stability is regulated by $GSK-3{\alpha}$. Here, we show that Notch1/NICD levels are significantly regulated by $GSK-3{\beta}$ and by $GSK-3{\alpha}$. Treatment with LiCl (a specific GSK-3 inhibitor) or the overexpression of the kinase-inactive forms of $GSK-3{\alpha}/{\beta}$ significantly increased Notch1/NICD levels. Endogenous NICD levels were also increased by either $GSK-3{\alpha}/{\beta}$- or $GSK-3{\alpha}$-specific siRNA. Furthermore, it was found that $GSK-3{\alpha}$ binds to Notch1. Deletion analysis showed that at least three Thr residues in Notch1 (Thr-1851, 2123, and 2125) are critical for its response to LiCl, which increased not only the transcriptional activity of endogenous NICD but also Hes1 mRNA levels. Taken together, our results indicate that $GSK-3{\alpha}$ is a negative regulator of Notch1/NICD.

• Journal of Embryo Transfer
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• v.26 no.4
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• pp.229-235
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• 2011

Sloan-Kettering virus gene product of a cellular protooncogene c-Ski is an unique nuclear pro-oncoprotein and belongs to the Ski/Sno proto-oncogene family. Ski plays multiple roles in a variety of cell types, it can induce both oncogenic transformation and terminal muscle differentiation when expressed at high levels. Ski protein is implicated in proliferation/differentiation in a variety of cells. The alternative fate of granulosa cells other than apoptosis is to differentiate to luteal cells, however, it is unknown whether Ski is expressed and has a role in granulosa cells undergoing luteinization. Thus, the aim of this study was, by means of immunohistochemical methods, to locate Ski protein in the rat ovaries during ovulation and corpora lutea (CL) formation to predict the possible involvement of Ski in luteinization. In addition, we performed to examine whether the initiation of luteinization with luteinizing hormone (LH) directly regulates expression of Ski in the luteinized granulosa and luteal cells after ovulation by in vivo models. In order to examine the expression pattern of Ski protein along with the progress of luteinization, follicular growth was induced by administration of equine chorionic gonadtropin to immature female rat, and luteinization was induced by human chorionic gonadtropin treatment to mimic luteinizing hormone (LH) surge. While no Ski-positive granulosa cells were present in preovulatory follicle, Ski protein expression was induced in response to LH surge, and was maintained after the formation of corpus luteum (CL). These results indicate that Ski is profoundly expressed in the luteinized granulosa cells and luteal cells of CL during luteinization, and suggest that Ski may play a role in luteinization of granulosa cells.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.30-36
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• 2012

The active fraction of soil organic matter, which includes organic debris and light organic fraction, plays a major role in nutrient cycling. In addition, particulate organic matter is a valuable index of labile soil organic matter and can reflect differences in various soil behaviors. Since soil organic matter bound to soil mineral particles has its density lower than soil minerals, we partitioned soil organic matter into debris ($<1.5g\;cm^{-3}$), light fraction ($1.5-2.0g\;cm^{-3}$), and heavy fraction ($>2.0g\;cm^{-3}$), based on high density $ZnCl_{2-}$ sucrose solutions. Generally, partitioned organic bands were clearly separated, demonstrating that the $ZnCl_{2-}$ sucrose solutions are useful for such a density gradient centrifugation. The available gradient ranges from 1.2 to $2.0g\;cm^{-3}$. Although there was not a statistically meaningful difference in organic debris and organomineral fractions among the examined soils, there was a general trend that a higher content of organic debris resulted in a higher proportion of light organomineral fraction. In addition, high clay content was associated with increased fraction of light organomineals. Partitioning of soil organic carbon revealed that carbon content is reduced in the heavy fraction than in the light fraction, reflecting that the light fraction contains more fresh and abundant carbon than the passive resistant fraction. It was also found that carbon contents in the overall organic matter, debris, light fraction, and heavy fractions may differ considerably in response to different farming practices.

• Applied Biological Chemistry
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• v.41 no.1
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• pp.53-59
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• 1998

The Rhizobium and Azospirillum spp. were isolated from the root nodules of several leguminous plants and rhizosphere of various paddy rice varieties. The growth of the nitrogen-fixing strains isolated was largely inhibited in yeast extract-mannitol medium (AMA) containing 0.6 M NaCl. In response to osmotic stress, the nitrogen-fixing strains accumulate intracellular free glutamate. The growth and nitrogenase activity of Rhizobium and Azospirillum were increased by addition of osmoprotectants such as proline, glycine betaine, and glutamate during salt stress. Glycine betaine was the most effective among exogenous osmoprotectants tested. In the absence of sodium chloride, nitrogenase activity seem to be slightly decreased by the presence of the proline or glycine betaine. These results revealed that nitrogenase activity was repressed by fixed nitrogens such as proline or glycine betaine.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.6
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• pp.437-443
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• 2011

Salt signals in tongue are relayed to the nucleus of the solitary tract (NST). This signaling is very important to determine whether to swallow salt-related nutrition or not and suggests some implications in discrimination of salt concentration. Salt concentration-dependent electrical responses in the chorda tympani and the NST were well reported. But salt concentration-dependency and spatial distribution of c-Fos in the NST were not well established. In the present study, NaCl signaling in the NST was studied in urethane-anesthetized rats. The c-Fos immunoreactivity in the six different NST areas along the rostral-caudal axis and six subregions in each of bilateral NST were compared between applications of distilled water and different concentrations of NaCl to the tongue of experimental animals. From this study, salt stimulation with high concentration (1.0 M NaCl) induced significantly higher c-Fos expression in intermediate NST and dorsal-medial and dorsal-middle subregions of the NST compared to distilled water stimulation. The result represents the specific spatial distribution of salt taste perception in the NST.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.4
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• pp.130-138
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• 2004

Food wastes with different regional origins were mixed with bulking agent such as paper mill sludge or night soil, and aged for 21 days or 28 days. And aged food wastes were fed to the earthworm(tiger worm, Eisenia fetida) for 60 days. There were no significant physico-chemical differences among the food wastes with different regional origins. EC values and NaCl concentrations in food wastes were too high for earthworms to survive. Food wastes mixed with paper mill sludge were vermicomposted more efficiently than food wastes mixed with night soil, but the over-all vermicomposting rates on the food wastes were much lower than that on paper mill sludge because EC values and NaCl concentrations were still high for earthworm to compost the feeds. Earthworm population did not increase its biomass on the food wastes mixed with paper mill sludge or night soil, whereas earthworm population fed with paper mill sludge increased its biomass by 20% for 60 days. It could be concluded that a solution for reducing NaCl concentrations in food waste should be developed to vermicompost food waste.

• Ocean and Polar Research
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• v.27 no.1
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• pp.59-65
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• 2005

To assess the effect of anaesthetic on stress response in cultured sweetfish (Plecoglossus altivelis) during transportation, the levels of plasma cortisol, glucose, lactic acid, $Na^+,\;K^+,\;Cl^-$, osmolality and survival were determined. The transportation was performed in square boxes where liquefied oxygen was saturated in polyethylene bags. Fish transportation was carried by car for 2 hours after anaesthesis with lidocaine-HCl/1,000 ppm $NaHCO_3$ in experiment. Mean plasma cortisol concentration before transportation was 170.7ng/ml. After transportation, the levels of plasma cortisol increased to 518.5ng/ml (Control), 461.9ng/ml (Sham control), 369.4ng/ml (20ppm anaesthetic), 304.0ng/ml (40 ppm anaesthetic), 405.7ng/ml (80 ppm anaesthetic) and 499.1ng/ml (160ppm anaesthetic) in each experimental groups, respectively (p<0.05). However levels of glucose, lactic acid, $Na^+,\;Cl^-$ and osmolality in 40ppm anaesthetic group did not show significant differences in this before and after transportation (P>0.05). These result reveal an anaesthetic lidocaine HCl/1,000ppm $NaHCO_3$ is effective as sedative for transportation mixture in this species. This research provides baseline data on cortisol, glucose, lactic acid, $Na^+,\;K^+,\;Cl^-$, osmolality and survival for anaesthetic transportation.

• BMB Reports
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• v.38 no.4
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• pp.481-485
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• 2005

The response of Spirulina (Arthrospira) platensis to high salt stress was investigated by incubating the cells in light of moderate intensity in the presence of 0.8 M NaCl. NaCl caused a decrease in photosystem II (PSII) mediated oxygen evolution activity and increase in photosystem I (PSI) activity and the amount of P700. Similarly maximal efficiency of PSII (Fv/Fm) and variable fluorescence (Fv/Fo) were also declined in salt-stressed cells. Western blot analysis reveal that the inhibition in PSII activity is due to a 40% loss of a thylakoid membrane protein, known as D1, which is located in PSII reaction center. NaCl treatment of cells also resulted in the alterations of other thylakoid membrane proteins: most prominently, a dramatic diminishment of the 47-kDa chlorophyll protein (CP) and 94-kDa protein, and accumulation of a 17-kDa protein band were observed in SDS-PAGE. The changes in 47-kDa and 94-kDa proteins lead to the decreased energy transfer from light harvesting antenna to PSII, which was accompanied by alterations in the chlorophyll fluorescence emission spectra of whole cells and isolated thylakoids. Therefore we conclude that salt stress has various effects on photosynthetic electron transport activities due to the marked alterations in the composition of thylakoid membrane proteins.

• Animal cells and systems
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• v.4 no.2
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• pp.181-186
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• 2000

The expression of $p21^{WAF1/ClP1/SDl1}$, one of the cyclin-dependent kinase inhibitors, is regulated by a variety of transcription factors including p53 and STAT. Heat shock induces the expression of p21 in a temperature- and time-dependent manner. Although the p21 induction by heat shock has been reported to be controlled by p53, a p53-independent mechanism Is also involved. To understand the p53-independent regulation of heat shock-induced p21 expression, we searched the promoter region of p21 gene and found one or two heat shock element (HSE)-like sequences in human, rat, and mouse. Electromobility shift assay (EMSA) showed that heat shock factor (HSF) could bind to these HSE-like sequences In response to heat shock, even though to a lesser extent than to HSE. In addition, p21 promoter deletion analysis revealed that heat shock activated a p21 deletion promoter construct containing the HSE-like sequences but lacking p53-binding sites, but not a promoter construct containing neither HSE-like sequences nor the p53-responsive element. Furthermore, the p21 induction by heat shook was significantly inhibited in confluent cells in which heat shock-induced HSF activation was reduced. These results suggest that the transcriptional regulation of p21 by heat shock may be mediated through activation and binding to HSE-like sequences of HSF.