• Development and Reproduction
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• v.14 no.1
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• pp.35-41
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• 2010

Mammalian reproduction is regulated by a feedback circuit of the key reproductive hormones such as GnRH, gonadotropin and sex steroids on the hypothalamic-pituitary-gonadal axis. In particular, the onset of female puberty is triggered by gain of a pulsatile pattern and increment of GnRH secretion from hypothalamus. Previous studies including our own clearly demonstrated that genistein (GS), a phytoestrogenic isoflavone, altered the timing of puberty onset in female rats. However, the brain-specific actions of GS in female rats has not been explored yet. The present study was performed to examine the changes in the activities of GnRH neurons and their neural circuits by GS in female rats. Concerning the drug delivery route, intracerebroventricular (ICV) injection technique was employed to eliminate the unwanted actions on the extrabrain tissues which can be occurred if the testing drug is systemically administered. Adult female rats (PND 100, 210-230 g BW) were anaesthetized, treated with single dose of GS ($3.4{\mu}g$/animal), and sacrificed at 3 hrs post-injection. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus, total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). ICV infusion of GS significantly raised the transcriptional activities of enhanced at puberty1 (EAP-1, p<0.05), glutamic acid decarboxylase (GAD67, p<0.01) which are known to modulate GnRH secretion in the hypothalamus. However, GS infusion could not change the mRNA level of nitric oxide synthase 2 (NOS-2). GS administration significantly increased the mRNA levels of KiSS-1 (p<0.001), GPR54 (p<0.001), and GnRH (p<0.01) in the hypothalami, but decreased the mRNA levels of LH-$\beta$ (p<0.01) and FSH-$\beta$ (p<0.05) in the pituitaries. Taken together, the present study indicated that the acute exposure to GS could directly activate the hypothalamic GnRH modulating system, suggesting the GS's disrupting effects such as the early onset of puberty in immature female rats might be derived from premature activation of key reproduction related genes in hypothalamus-pituitary neuroendocrine circuit.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.855-858
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• 2005

The bioavailability of Ca is currently one of the most important topics in nutrition research and is correlated with gastrointestinal solubility. Thus, to increase the solubility of calcium, this study was undertaken to examine the effect of $\gamma$-PGA on intestinal Ca solubility. The calcium solubility increased when the amount of $\gamma$-PGA was increased, due to the inhibition of the formation of an insoluble Ca complex with phosphate. Therefore, when $\gamma$-PGA-500 (avg. MW 5,000 kDa) was added at 0.5 mg/ml, $75\%$ of the total Ca was soluble. The amount of soluble Ca uptake in the small intestine was investigated using Balb/c mice as an animal model system. The soluble Ca uptake in the mice orally administered with $\gamma$-PGA-500 (avg. MW 5,000 kDa) was significantly higher than that in the $\gamma$-PGA-l00 (avg. MW 1,000 kDa)-administered mice (P<0.05). Accordingly, these results strongly support the notion that the molecular size of $\gamma$-PGA is correlated with Ca solubility. The effects of other factors, such as casein phosphopeptide and vitamin D, on intestinal Ca absorption have also previously been investigated. Therefore, it is hoped that the present observations will help clarify the role of $\gamma$-PGA in Ca solubility and its industrial application as an additive.

• Analytical Science and Technology
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• v.7 no.3
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• pp.285-291
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• 1994

A microbial BOD sensor for the continuous estimation of BOD was been developed by immobilizing Trichosporon cutaneum, which was immobilized between a dialysis and a gas-permeable membrane, on an oxygen electrode. The optimum pH and temperature for BOD measurement using this sensor were pH 7.0 and $32{\sim}33^{\circ}C$, respectively. The best result was obtained at 2~3ml/min flow rate in 0.1M phosphate buffer solution. A linear relationship was observed between ${\Delta}DO$ and the concentration of standard GGA solution below 60mg/l(90ppm $BOD_5$). The reproducibility was found to be within 3% for the standard solution containing glucose 30mg/l and glutamic acid 30mg/l. The output DO value of this sensor was almost constant for 30 dalys. The response time and the recovery time were about 5 and 10 min, respectively. This sensor was employed for the BOD measurement of waste pollutants and was compared with $BOD_5$ method.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.666-674
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• 2016

The bacterial strains were screened as potential starters for fermenting low-salt doenjang (a Korean traditional fermented soybean paste) using Korean doenjang based on proteolytic and antipathogenic activities under 6.5-7.5% NaCl conditions. Phylogenetic analysis based on 16S rRNA gene sequences showed that they all belonged to the genus Bacillus. Proteolytic and antipathogenic activities against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, and Aspergillus flavus, as well as fibrinolytic, amylase, and cellulase activities of the 10 strains were quantitatively evaluated. Of these, strains D2-2, JJ-D34, and D12-5 were selected, based on their activities. The functional, phenotypic, and safety-related characteristics of these three strains were additionally investigated and strains D2-2 and D12-5, which lacked antibiotic resistance, were finally selected. Strains D2-2 and D12-5 produced poly-γ-glutamic acid and showed various enzyme activities, including α-glucosidase and β-glucosidase. Growth properties of strains D2-2 and D12-5 included wide temperature and pH ranges, growth in up to 16% NaCl, and weak anaerobic growth, suggesting that they facilitate low-salt doenjang fermentation. Strains D2-2 and D12-5 were not hemolytic, carried no toxin genes, and did not produce biogenic amines. These results suggest that strains D2-2 and D12-5 can serve as appropriate starter cultures for fermenting low-salt doenjang with high quality and safety.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.269-273
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• 2012

본 연구는 알려진 녹차의 다양한 항산화, 항염 효능이 있는 Polyphenol 류 이외의 생물학적 활성을 가지는 펩타이드 및 당단백질 소재에 대한 특성과 분석을 위하여 연구되었다. 녹차에서 수용성 성분을 추출 후 알콜 침전방법을 사용하여 단백질과 펩타이드류를 분리하여 실험에 사용하였다. 전체 추출물 중에는 Glutamic acid가 14073.9ug/g, (39.11%)로 가장 높게 분석되었으며, GPC 분석결과 Mn 886, Mw 25218, Mp 890, Mw/Mn 28.46으로 분석이 되었으며, 전체적으로 3개의 피크로 분석되었다. 함유된 펩타이드를 분석하기 위하여 HPLC를 이용하여 RT 16.148min의 Fraction을 분리하여 펩타이드 분석결과 녹차에서 유래한 TNTLSN이라는 hexapeptide를 동정하였다. 이러한 펩타이드는 친수성이며, 안정도가 높은 특징을 가지고 있고, 분자량이 1000이하로 피부 흡수도가 높을 것으로 기대되며, Biodegradable하며, Renewable 한 자연 친화적인 화장품 소재로서 널리 활용될 수 있을 것으로 판단된다.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.76-81
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• 1991

- The effect of redox potential (ORP) on lysine production by a leucine auxotrophic regulatory mutant of Corynebacterium glutclmicum on molasses medium was investigated in a 2-1 jar fermentor at pH 6.9 and $32^{\circ}C$. At a dilution rate of D=O.l $h ^1$, a maximum yield of Yr,,s=0.24 was obtained in either carbon- or leucine-limited chemostat where the redox potential was between -60 mV and - 100 mV. This level of redox potential corresponded to moderate oxygen deficiency. Under a high oxygen deficient condition of the redox potential of - 130 rnV (oxygen-limited chemostat), all the kinetic parameters such as $Y_[p/s}, q_s\; and \; q_p$ were decreased significantly and significant amounts of byproducts including glycine, alanine and valine were accumulated in the culture, indicating that the control of redox potential is important in lysine fermentation. At the redox potential of - 40 mV, on the other hand, large quantities of arginine (up to 0.38g/l) and glutamic acid (up to 0.12 g/l) were produced. A maximum lysine productivity of 2.41 g/l/h was achieved at - 66 mV under a carbon-limited condition.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1120-1123
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• 1999

The isolation of taurine from cooking wastes of anchovy factory ship was conducted. Anchovy cooking wastes had 93.9% moisture, followed by 4.8% ash, 0.4% protein and 0.2% lipid in order. Free amino acids of anchovy cooking wastes consisted of 38.8% taurine, 26.6% histidine and 10.0% glutamic acid. Taurine-rich fraction was isolated by cation and anion exchange chromatography with its yield and purity being 79.2% and 89.9%, respectively. The 80% ethanol precipitate obtained from the taurine-rich fraction showed yield of 29.5% and purity of 98.1% as taurine.

• Journal of Environmental Science International
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• v.13 no.4
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• pp.413-420
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• 2004

The objectives of present study were to investigate the effects of benzo[a]pyrene(BaP) on cytotoxicity, lipid peroxidation and antioxidant enzymes in rat hepatocyte primary culture. Primary cultures of rat hepatocytes were incubated for 24 hr, 48 hr or 72 hr in the presence of various concentrations (0, 10, 20, 30, 50 or 100 $\mu.$ M) of BaP. Cytotoxicity and cell viability were determined by measuring glutamic oxaloacetic transaminase(GOT) activity, lactate dehydrogenase(LDH) activity and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MIT) value. Lipid peroxidation was evaluated using thiobarbituric acid reactive substances(TBARS) assay. Effects on antioxidant system were determined by measuring glutathione peroxidase(GPx) activity, glutathione reductase(GR) activity and glutathione concentration. Activities of GOT and LDH, MTT value as well as TBARS concentration were not affected by up to 100 $\muM$ of BaP for 24 hr incubation. However, BaP at the concentration of 50 $\muM$ for 48 hr incubation or at the concentration of 30 $\muM$ for 72 hr incubation began to increase LDH activity and TBARS concentration but decrease MTT value, representing that BaP caused cytotoxicity and decreased cell viability in dose- and time-dependent manners. GPx activity began to be decreased by BaP at the concentration of 50 $\muM$ for 72 hr incubation. Whereas, GR activity began to be decreased by BaP at the concentration of 20 $\muM$ for 72 hr incubation. Glutathione concentration began to be decreased by BaP at the concentration of 20 $\muM$ for 72 hr incubation and was further reduced to 90% by 100 $\muM$ of BaP. These results demonstrate that BaP caused cytoctoxicity and decreased cell viability by increasing lipid peroxidation and decreasing glutathione concentration as well as activities of GPx and GR.

• KSBB Journal
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• v.10 no.3
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• pp.249-256
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• 1995

${\gamma}$-Glutamylcysteine production by the immobilized microbial system of recombinant Escherichia coli and yeast was investigated. ${\gamma}$-Glutamylcysteine was synthesized from L-glutamic acid and L-cysteine in the presence of ATP by the reaction catalyzed by ${\gamma}$-glutamylcysteine synthetase. An immobilized microbial cell system was developed for the efficient ${\gamma}$-glutamylcysteine production. Recombinant Escherichia coli and yeast were immobilized by alginate. Production of ${\gamma}$-glutamylcysteine was better with the recombinant Escherichia coli for both the synthesis of ${\gamma}$-glutamylcysteine and the ATP regeneration than the mixed system of recombinant Escherichia coli and yeast. The proper radio of recombinant Escherichia coli to yeast was experimentary observed to be 1:4 in the mixed system. Although the immobi1ized system had the slower reaction rate, its reaction stability was increased by 10%.

• The Korean Journal of Food And Nutrition
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• v.25 no.3
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• pp.529-537
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• 2012

This study examined the manufacturing characteristics of sweet potato doenjang in order to gain a more efficient use of the sweet potato. Sweet potato(Sinwhangmi, Sinjami) koji(mixed sweet potato paste and soybean powder in a ratio of 1:1) was cultured with Aspergillus oryzae KCCM 11372 at $35^{\circ}C$ for 48 h. Sweet potato doenjang was fermented for 60 days using a sweet potato koji(20%, 45%) and steamed soybean(70%, 45%), with salt accounting for 10%. The glutamic acid content was determined to be much higher in sweet potato doenjang using Sinwhangmi koji(45%) and steamed soybean (45%), than that of general doenjang. The DPPH radical scavenging activity has the largest $EC_{50}$(0.9 mg) in sweet potato doenjang using Sinjami potatoes 45%. Sensory evaluation indicated a good preference for sweet potato doenjang using Sinwhangmi(45%) and steamed soybean(45%).