• Microbiology and Biotechnology Letters
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• v.13 no.1
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• pp.19-25
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• 1985

The HIS5 gene of Saccharomyces cerevisiae host was encoded histidinol phosphate aminotransferase(E.C.: 2.6. 1.9). The HIS5 gene of Saccharomyces cerevisiae was cloned on plasmid pSH 530. This gene mighted be transcripted from a promoter of yeast gene both in E. coli and yeast hosts. We have determined the nucleotide sequence of the yeast HIS5 gene and its 5' and 3' flanking sequences. There are no large differences between the relative levels of HIS5 mRNA molecules with different 5' termini in represent and derepressed cell. In the DNA sequence upstream from the 5' termini of HIS5 mRNA we have found live closely related copies of a 9 base pair sequence. The sequence is also repeated in the 5' noncoding regions of HIS1, HIS3, HIS4, HIS5 and TRP5. Closely related sequence are not found flanking repeat sequence plays a role in the regulation of amino acid biosynthetic genes subject to the general amino acid control.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1904-1911
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• 2006

The cell-free extracts of 250 yeasts were screened for their in vitro anti-angiogenic activity, to develop a new cancer metastasis inhibitor. Saccharomyces cerevisiae K-7 was selected as the producer of the anti-angiogenic agent, because it had the highest anti-angiogenic activity. The anti-angiogenic agent was produced maximally from hydrolysates of Saccharomyces cerevisiae K-7, when the yeast was cultured in yeast extract-peptone-dextrose medium at 30$^{\circ}C$ for 24 h, and cell-free extracts were than digested with pepsin for 4 h at 37$^{\circ}C$. The anti-angiogenic agent was further purified by ultrafiltration, Sephadex G-25 gel permeation chromatography and reverse-phase HPLC, and the anti-angiogenic activity of the final purified preparation was 72.7% at 10 $\mu$M/egg. The purified anti-angiogenic agent was found to originate from the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) molecule of Saccharomyces cerevisiae K-7, and its peptide sequence was Val-Ser-Trp-Tyr-Asp-Asn-Glu-Tyr-Gly-Tyr-Ser-Thr-Arg-Val-Val-Asp. In the MTT assay, the shape of the HT-l 080 cell was clearly changed to a circular type at 0.2 mM purified anti-angiogenic agent. This result indicated that the growth of the HT-I080 cell was significantly inhibited at 0.2 mM of the purified anti-angiogenic agent. The MMP activity of the treated HT-l080 cells was not affected, evidenced by the gelatin zymography, indicating that the anti-angiogenic mechanism of the purified anti-angiogenic agent is not mediated through MMP activity.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.595-600
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• 1998

In order to investigate a relationship of the structure-antifungal and hemolytic activities between cecropin A(1-8)-magainin 2(1-12) and cecropin A(1-8)-melittin(1-12) hybrid peptides, several analogues with amino acid substitution at positions 10 (Ile) and 16 (Ser) were designed and synthesized. The increase of the hydrophobicity by substituting with Leu, Phe, and Trp at position 16 in cecropin A(1-8)-magainin 2(1-12) did not have a significant effect on antifungal activity but caused a remarkable increase in hemolytic activity. These results indicate that the hydrophobic property at position 16 of cecropin A(1-8)-magainin 2(1-12) is more correlated to hemolytic activity than to antifungal activity. Replacement with Pro at position 10 of cecropin A(1-8)- magainin 2(1-12) and cecropin A(1-8)-melittin (1-12) caused a remarkable decrease in a-helical contents in the 50% TFE solution and induced a reduction in lytic activity against Aspergillus flavus, and Aspergillus fumigatus. These results demonstrate that flexibility at the central hinge region is essential for lytic activity against fungal cells and $\alpha$-helicity of the peptides.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.130-141
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• 1997

Work on the reduction of particulate matter(PM) from a diesel vehicl has led to a new trp system and a control method to control the combustion rate of the PM filtrated in the trap, which was named as 'Active Exhaust Feeding Regeneration(AEFR) System' by its operation mechanism. Ceramic cordierite filter is a major component of the trap and susceptible to thermal shock. Therefore the system should be designed to reduce the peak temperature and temperature gradients in the trap ; these have been considered to be the main factors causing thermal shock of the filter during the regeneration. It uses the engine's exhaust gas partially for the regeneration of the ceramic filter. It controlled bypass flow rate of the engine's exhaust gas precisely to control the temperature of the gas entrained into the filter. Gas temperatures were measured inside filter, and the oxygen concentration at the outlet of the filter was also monitored during the regeneration to analyze the combustion process of the PM. The temperature distributions and temperature gradients in the filter during the regeneration varied widely according to the regeneration control schemes. Finally, this system shows relatively low peak temperature and temperature gradients in the filter during its regeneration. It is considered that this system uses a mew method to control the combustion rate of the PM, which is different from the methods used in the previous studies.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.3
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• pp.406-409
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• 2002

The effect of refeeding with various single essential amino acids on the recovery of plasma insulin-like growth factor-I (IGF-I) concentration in fasted young chickens was examined. Young chickens (29 days of age) were divided into 15 experimental groups. Chickens in one group were fed on the commercial diet ad libitum for 4 days. The remaining 56 chickens in 14 experimental groups were fasted. After 2 days of fasting, 52 chicks in 13 fasted groups were refed with one of the following experimental diets for 2 days. Eleven experimental diets were protein-free diets supplemented with one of 11 essential amino acids (Arg, Gly, His, Ileu, Leu, Met, Phe, Lys, Thr, Trp, Val). The remaining 2 experimental diets were a protein-free diet containing 11 essential amino acids and a protein-free diet not supplemented with amino acids. Birds in the remaining fasted group continued to be fasted for 2 days. Fasting for 2 days markedly reduced plasma IGF-I concentration. When fasted chickens were refed the protein-free diet containing either Gly alone or all essential amino acids, plasma IGF-I concentration was recovered to the level similar to that of fed chickens. Protein-free diet alone, however, failed to restore the reduced IGF-I concentration in plasma. Body weight loss modulated by feeding with protein-free diets supplemented with various single essential amino acids was associated with changes in plasma IGF-I concentrations. We concluded that body weight loss by feeding with a protein-free diet was lower than that of fasted chickens and that body weight loss associated with the decrease in plasma IGF-I concentration was modulated by feeding with protein-free diets containing various single essential amino acids.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.1
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• pp.1-7
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• 1998

A total of 120 pigs $(L\;{\times}\;LW\;{\times}\;D)$ averaged 14.16 kg of body weight were reared under six dietary treatments to evaluate the effects of amino acid supplementation on their performances. Treatments were 1) 18% CP diet (control); 2) 15% CP+0.28% Lys (B, 15L); 3) B+0.06% Met (15LM); 4) B+0.13% Thr (15LT) ; 5) B+0.06% Met+0.13% Thr (15LMT); 6) B+0.06% Met+0.13% Thr+0.05% Trp (15LMTT). Each treatment had 4 replicates with 5 pigs per replicate. The daily weight gains were statistically similar in 15LMT, 15LMTT and control groups. Threonine and methionine supplementation resulted in improved growth performance and nutrient digestibilities, while tryptophan supplementation had little beneficial effect. However, the best feed conversion was found in the control group. Dry. matter and CP digestibilities were improved in the 15LMT and 15LMTT groups. Gross energy, crude fat and phosphorus digestibilities were not affected by the treatment. Among the 15% CP groups, nitrogen digestibility showed the tendency to be increased as the more synthetic amino acids were added. Dry matter and nitrogen excretions were significantly reduced by feeding low protein, amino acid fortified diets, while phosphorus excretion was not influenced. Essential amino acids digestibility was higher in 15LT, 15LMT and 15LMTT groups and lower in the control. The 15LT group showed the best lysine digestibility, and methionine digestibilities were higher in all treated groups than control one. Threonine digestibilities higher in 15LT 15LMT, and 15LMTT than the control. The result shows that threonine and methionine should be added to the diet containing 15% CP diet, fortified with lysine to get same performance of 18% CP diet.

• Journal of Microbiology and Biotechnology
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• v.23 no.8
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• pp.1070-1075
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• 2013

Streptococcus mutans is the primary etiological agent of dental caries. The antimicrobial peptide $\small{D}$-Nal-Pac-525 was designed by replacing the tryptophans of the Trp-rich peptide Pac-525 with $\small{D}$-${\beta}$-naphthyalanines. To assess the effect of $\small{D}$-Nal-Pac-525 on cariogenic bacteria, the activity of $\small{D}$-Nal-Pac-525 on the growth of S. mutans and its biofilm formation were examined. $\small{D}$-Nal-Pac-525 showed robust antimicrobial activity against S. mutans (minimum inhibitory concentration of 4 ${\mu}g/ml$). Using scanning electron microscopy and transmission electron microscopy, it was shown that $\small{D}$-Nal-Pac-525 caused morphological changes and damaged the cell membrane of S. mutans. $\small{D}$-Nal-Pac-525 inhibited biofilm formation of S. mutans at 2 ${\mu}g/ml$. The results of this study suggest that $\small{D}$-Nal-Pac-525 has great potential for clinical application as a dental caries-preventing agent.

• Nutrition Research and Practice
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• v.8 no.2
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• pp.146-150
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• 2014

BACKGROUND/OBJECTIVES: Cholecystokinin (CCK), a hormone or neuropeptide, is secreted in response to intraluminal nutrients by enteroendocrine I-cells of the intestine and has important physiological actions related to appetite regulation and satiety. The stimulation on CCK secretion from the intestine is of potential relevance for body weight management. Naringenin (4',5,7-trihydroxyflavanone) and its glycoside naringin (naringenin 7-rhamnoglucoside) have been reported to have many biological functions. In the current study, we investigated the question of whether naringenin and naringin could stimulate CCK secretion and then examined the mechanisms involved in CCK release. MATERIALS/METHODS: STC-1 cells were used as a model of enteroendocrine cells. CCK release and changes in intracellular $Ca^{2+}$ ($[Ca^{2+}]_i$) were measured after incubation of cells with naringenin and naringin for 1 h. RESULTS: Naringenin caused significant (P < 0.05) stimulation of CCK secretion, but naringin did not. In addition, regarding the secretory mechanisms, naringenin-induced CCK secretion involved increases in $[Ca^{2+}]_i$, influx of extracellular $Ca^{2+}$, at least in part, and activation of TRP channels, including TRPA1. CONCLUSION: Findings of this study suggest that naringenin could have a role in appetite regulation and satiety.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.409-413
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• 2012

Indolicidin (ID) is a 13-residue Trp-rich antimicrobial peptide (AMP) isolated from bovine neutrophils. In addition to having a high antimicrobial potency, it is also toxic to mammalian cells. To develop novel ID-derived AMPs with shorter lengths and enhanced prokaryotic selectivities (meaning potent antimicrobial activity against bacterial cells without toxicity against mammalian cells) over the parental ID, several ID analogs were designed and synthesized. Finally, 10-residue ID analogs (SI, SI-PA, SI-WF and SI-WL) with much higher prokaryotic selectivity than the parental ID were developed. Our results suggest that the hydrophobic and aromatic amino acids at the central position of the analog SI with the highest prokaryotic selectivity are important for potent antimicrobial activity, but two Pro residues do not affect antimicrobial activity. The order of prokaryotic selectivity for ID and its designed analogs was SI > SI-PA > SI-WF > SI-WL > ID > SI-WA. Taken together, our designed short ID analogs could be developed as therapeutic agents for treating bacterial infections.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.3
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• pp.388-394
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• 2020

An emerging interest in healthy eating has led to an increase in the consumption of rice mixed with various types of grains. Cooked rice was prepared with five different seaweeds, Hizikia fusiformis, Sargassum fulvellum, Enteromorpha compressa, Undaria pinnatifida, and Gracilaria verrucosa, and the antioxidant activity was measured. In addition, the antioxidant activities of 80% ethanol and methanol extracts of the five seaweeds were compared. Total phenolic content (TPC), total reducing power (TRP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) cation radical scavenging activities of the ethanol extracts were higher than those of the methanol extracts. The TPC of raw seaweed ethanol extracts was from 7.58 to 26.27 mg gallic acid equivalent (GAE)/g. The antioxidant activities of both extracts of Hizikia fusiformis were the highest among the five seaweeds, and the antioxidant activities of the cooked rice were lower than those of the raw seaweed extracts. The DPPH radical scavenging activities of cooked white rice, mixed grains, barley, and a mixture of white rice and barely added with Hizikia fusiformis, Sargassum fulvellum and Undaria pinnatifida were 3.17, 23.12, 31.11 and 10.66%, respectively. These results demonstrate the addition of seaweeds to cooked rice helps to improve the antioxidant activity compared to white rice alone.