• Journal of Photoscience
• /
• v.11 no.1
• /
• pp.25-28
• /
• 2004

The kinetics of the loss of leaf fresh weight during incubation of barley and rice leaves in 9% or 15% NaCl solutions were biphasic, indicating the existence of a controlling mechanism for water transport. The first rapid phases reached their plateaus within 1 and 2 h in the case of rice and barley leaves, respectively. When barley leaves were fed with sodium fluoride, an inhibitor of phosphatase inhibitor, through their epicotyls for 3 h in darkness, prior to the treatment of NaCl, the biphasic pattern shown during NaCl treatment was disappeared resulting in linear decreases in the relative fresh weights. The results suggest that NaF accelerates salt-induced water efflux from plant cells, possibly by inhibiting the protection mechanism that may act in NaF-untreated leaves. The linear water loss can be explained in terms of phosphorylation of aquaporin by blocking its dephosphorylation in the presence of the phosphatase inhibitor to keep aquaporin in a phosphorylated form. However, the effect of NaF shown in barley leaves were not observed in rice. These results suggest that the regulation of water transport depends on plant species, and the mechanism for the controlling water transport in rice is different from that of barley.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.3
• /
• pp.381-385
• /
• 2000

The effect and interaction of Ca and B on exopolysaccharide (EPS) synthesis in the diazotrophically growing cyanobacterium. Nostoc spongiaeforme, was investigated. The absence of B inhibited EPS synthesis 1.56-fold ($16\mu\textrm{g}$ glucose equivalent/mg dry weight, 16 d) over the control cells ($25\mu\textrm{g}$ glucose equivalent) grown in medium containing 0.5 mM Ca and $8{\mu}{\textrm}{m}$ B. When B concentration was raised to $40{\mu}{\textrm}{m}$, EPS production was stimulated 1.8-fold. Reduction of Ca concentraion to one-half (0.25 mM) resulted in increased B demand (16$\muM$) by the cells for EPS production at par with the normal sets. However, without Ca, EPS production also increased as B increased. Addition of B to a Ca-free medium stimulated cyanobacterial diazotrophic growth as well as synthesis of Chl a and phycocyanin (0-8 d). The data suggest B-dependent diazotrophic growth during Ca-deficiency and point to and important interactive role of Ca and B in regulation of cyanobacterial EPS synthesis.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.11
• /
• pp.1548-1551
• /
• 2005

The leptin, an anti-obesity protein, is a hormone protein expressed and secreted mainly from adipocyte tissue, and involved in regulation of body weight, food intake and energy metabolism. In an effort to discover polymorphism(s) in genes whose variant(s) might be implicated in phenotypic traits of growth, we have sequenced exons and their boundaries of leptin gene including 1,000 bp upstream of promoter region with twenty-four unrelated Korean cattle. Fifty-seven sequence variants were identified: fourteen in 5' flanking region, twenty-seven in introns, eight in exons, and eight in 3' flanking region. By pair-wise linkage analysis among polymorphisms, ten sets of SNPs were in absolute linkage disequilibrium (LD) (|D'| = 1 and $r^2$ = 1). Among variants identified, thirty-six SNPs were newly identified, and twenty-one SNPs, which were reported in other breeds, were also confirmed in Korean cattle. The allele frequencies of variants were quite different among breeds. The information from SNPs of bovine leptin gene could be useful for further genetic studies of this gene.

• Toxicological Research
• /
• v.14 no.2
• /
• pp.273-283
• /
• 1998

Single and 4 weeks oral administration of New wonbangwoohwangchungsimwon (NSCH) which was used l-muscone as substitutive material qf musk, to beagle dogs of both sexes were per-formed to investigate both acute and subacute toxicity. Beagle dogs (3 males and 3 females) in acute experiments were administered orally with single dose of 2,000 mg/kg and groups of 9 male and 9 female beagle dogs in subacute experiments were given daily different dosage of NSCH, 160 mg/kg/day (low dosage group), 400 mg/kg/day (middle dosage group), 1,000 mg/kg/day (high dosage group) once a day for 4 weeks by oral route according to the Established Regulation of Korea Food and Drug Ad-ministration (l996. 4. 16). $LD_{50}$ value for beagle dogs was more than 2,000 mg/kg per oral for both male and females. In animals administered with NSCH, there were neither dead animals nor significant changes of body weights. In addition, no differences were found between control and treated groups in clinical sign, urinalysis, eye examination, hematology, serum chemistry, organ weight and other fingings. No histological lesions were observed in both control and treatment groups. Above data strongly suggset that NSCH in beagle dogs is considered to be safe.

• Toxicological Research
• /
• v.14 no.2
• /
• pp.249-260
• /
• 1998

Single and 4 weeks oral administration of New Woohwangchungsimwon (NWCH) which was used l-muscone as substitutive material of musk, to beagle dogs of both sexes were performed to investigate both acute and subacute toxicity. Beagle dogs(3 males and 3 females) in acute experiments were administered orally with single dose of 2,000 mg/kg and groups of 9 male and 9 female beagle dogs in subacute experiments were given daily different dosage of NWCH, 160 mg/kg/day (low dosage group), 400 mg/kg/day (middle dosage group), 1,000 mg/kg/day (high dosage group) once a day for 4 weeks by oral route according to the Established Regulation of Korea Food and Drug Administration (1996. 4. 16). $LD_{50}$/ value for beagle dogs was more than 2,000 mg/kg per oral for both male and fe-males. In animals administered with NWCH, there were neither dead animals nor significant changes of body weights. In addition, no differences were found between control and treated groups in clinical sign, urinalysis, eye examination, hematology, serum chemistry, organ weight and other fingings. No histological lesions were observed in both control and treatment groups. Above data strongly suggset that NWCH in beagle dogs is considered to be safe.

• Proceedings of the KIEE Conference
• /
• 2006.10b
• /
• pp.154-158
• /
• 2006

The switching-mode power converter has been widely used because of its features of high efficiency and small weight and size. These features are brought by the ON-OFF operation of semiconductor switching devices. However, this switching operation causes the surge and EMI(Electromagnetic Interference) which deteriorate the reliability of the converter themselves and entire electronic systems. This problem on the surge and noise is one of the most serious difficulties in AC-to-DC converter. Random Pulse Width Modulation (RPWM) is peformed by adding a random perturbation to switching instant while output-voltage regulation of converter is performed. RPWM method for reducing conducted EMI in single switch three phase discontinuous conduction mode boost converter is presented. The more white noise is injected, the more conducted EMI is reduced. But output-voltage is not sufficiently regulated. This is the reason why carrier frequency selection topology is proposed. In the case of carrier frequency selection, output-voltage of steady state and transient state is fully regulated. A RPWM control method was proposed in order to smooth the switching noise spectrum and reduce it's level. Experimental results are verified by converter operating at 300v/1kW with $5%{\sim}30%$ white noise input. Spectrum analysis is performed on the Phase current and the CM noise voltage. The former is measured with Current Probe and the latter is achieved with LISN, which are connected to the spectrum analyzer respectively.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.5
• /
• pp.725-730
• /
• 1994

This study was conducted to investigate the effect of dietary zinc (Zn) and/or cadmium (Cd) on hepatic microsomal and cytosol enzyme activities. Male Spraque-Dawley rats (110$\pm$10g ) received zinc (0, 30 and 300 ppm/) and Cd-treated groups were administered oral intubation with Cd chloride (5.0mg/kg of body weight 0 at the same time once a week. The effect of Cd on the activity of hepatic cytochromep-450 , xanthine oxidase(X. O) and superoxide dismutase (SOd) was studied in rats. Cd oral intubation resulted in a decrease in cytochrome P-450 content and SOD activity whereas a significant increase in the X.O. activity was observed was observed . Intake of excessive Zn led to an increased activity of microsomal alcohol dehydrogenase (ADH) , whereas Zn deficiency group led to a decreased group. The mechanism by which Zn induces the decreasing of Cd toxicity in rats, seems to rely on the protection of the enzyme systems P-450, ADH, aldehyde dehydrogenase (ALDH) and X.O. in the liver, possibly by forming non-toxic Cd metallothionein. These results indicate that Zn and Cd regulation might occur via inhibitory protein component of the $H_2O$$_2$ -generator system.

• Journal of Periodontal and Implant Science
• /
• v.40 no.3
• /
• pp.119-124
• /
• 2010

Purpose: In addition to regulating body weight, leptin is also recognized for its role in the regulation of immune function and inflammation. The purpose of this study was to investigate the effect of leptin on Prevotella (P.) intermedia lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-$\alpha$ production in differentiated THP-1 cells, a human monocytic cell line. Methods: LPS from P. intermedia ATCC 25611 was prepared by the standard hot phenol-water method. THP-1 cells were incubated in the medium supplemented with phorbol myristate acetate to induce differentiation into macrophage-like cells. The amount of TNF-$\alpha$ and interleukin-8 secreted into the culture medium was determined by enzyme-linked immunosorbent assay (ELISA). TNF-$\alpha$ and Ob-R mRNA expression levels were determined by semi-quantitative reverse transcription-polymerase chain reaction analysis. Results: Leptin enhanced P. intermedia LPS-induced TNF-$\alpha$ production in a dose-dependent manner. Leptin modulated P. intermedia LPS-induced TNF-$\alpha$ expression predominantly at the transcriptional level. Effect of leptin on P. intermedia LPS-induced TNF-$\alpha$ production was not mediated by the leptin receptor. Conclusions: The ability of leptin to enhance P. intermedia LPS-induced TNF-$\alpha$ production may be important in the establishment of chronic lesion accompanied by osseous tissue destruction observed in inflammatory periodontal disease.

• Journal of Marine Bioscience and Biotechnology
• /
• v.12 no.1
• /
• pp.50-58
• /
• 2020

Sphacelaria is a filamentous brown algal genus that can be epibiotic on macroalgae, marine plants, and sea turtles. Its important role in benthic ecosystems, exposure to different stressors (e.g., grazing), and use as a model organism make Sphacelaria ideal for assessing physiological responses of organisms to environmental inputs. Single-cell RNA sequencing is a powerful new probe for understanding environmental responses of organisms at the molecular (transcriptome) level, capable of delineating gene regulation in different cell types. In the case of plants, this technique requires protoplasts ("naked" plant cells). The existing protoplast isolation protocols for Sphacelaria use non-commercial enzymes and are low-yielding. This study is the first to report the production of protoplasts from Sphacelaria fusca (Hudson) S.F. Gray, using a combination of commercial enzymes, chelation, and osmolarity treatment. A simple combination of commercial enzymes (cellulase Onozuka RS, alginate lyase, and driselase) with chelation pretreatment and an increased osmolarity (2512 mOsm/L H₂O) gave a protoplast yield of 15.08 ± 5.31 × 10⁴ protoplasts/g fresh weight, with all the Sphacelaria cell types represented. Driselase had no crucial effect on the protoplast isolation. However, the increased osmolarity had a highly significant and positive effect on the protoplast isolation, and chelation pretreatment was essential for optimal protoplast yield. The protocol represents a significant step forward for studies on Sphacelaria by efficiently generating protoplasts suitable for cellular studies, including single-cell RNA sequencing and expression profiling.

• Journal of Society of Preventive Korean Medicine
• /
• v.18 no.2
• /
• pp.101-113
• /
• 2014

Objective : Ephedra Herba has been widely used for patients with common cold, asthma in eastern countries, especially china japan and korea. Recently it has been also used for obesity in clinic with high frequency. This study was designed to investigate the effects of Ephedra Herba ethyl-acetate fraction (EEAF) on hyperlipidemic mice. Method : Effects on total cholesterol, HDL-cholesterol, triglyceride, AST, ALT, fasting blood glucose in serum were measured in this experiment, and in addition, histopathological and gene expression changes in liver tissue was also observed. Results : In our study, EEAF did not affect weight gain in hyperlipidemic mice. Oral administration of EEAF lowered levels of total cholesterol which were elevated by induction of hyperlipidemia. And administration of EEAF lowered fasting blood glucose significantly. By carrying out ontological analysis, large numbers of genes were identified in up or down regulated genes. The expression of the genes that were altered in response to high-fat diet was restored to normal levels in EEAF treated mice, with a recovery rate of 49%. And it was considered that fatty acid metabolism was one of important key pathway of the recovery. Conclusion : Results in our study suggest that EEAF can prevent obese and through regulation of dyslipidemia and hyperglycaemia.