• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.152-161
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• 2015

CodY is a highly conserved protein in low G+C gram-positive bacteria that regulates genes involved in sporulation and stationary-phase adaptation. Bacillus thuringiensis is a grampositive bacterium that forms spores and parasporal crystals during the stationary phase. To our knowledge, the regulatory mechanism of CodY in B. thuringiensis is unknown. To study the function of CodY protein in B. thuringiensis, BMB171codY^- was constructed in a BMB171 strain. A shuttle vector containing the ORF of cry1Ac10 was transformed into BMB171 and BMB171codY^-, named BMB171cry1Ac and BMB171codY^-cry1Ac, respectively. Some morphological and physiological changes of codY mutant BMB171codY^-cry1Ac were observed. A comparative proteomic analysis was conducted for both BMB171codY^-cry1Ac and BMB171cry1Ac through two-dimensional gel electrophoresis and MALDI-TOF-MS/MS analysis. The results showed that the proteins regulated by CodY are involved in microbial metabolism, including branched-chain amino acid metabolism, carbohydrate metabolism, fatty acid metabolism, and energy metabolism. Furthermore, we found CodY to be involved in sporulation, biosynthesis of poly-β-hydroxybutyrate, growth, genetic competence, and translation. According to the analysis of differentially expressed proteins, and physiological characterization of the codY mutant, we performed bacterial one-hybrid and electrophoretic mobility shift assay experiments and confirmed the direct regulation of genes by CodY, specifically those involved in metabolism of branched-chain amino acids, ribosomal recycling factor FRR, and the late competence protein ComER. Our data establish the foundation for in-depth study of the regulation of CodY in B. thuringiensis, and also offer a potential biocatalyst for functions of CodY in other bacteria.

• Korean Journal of Food Science and Technology
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• v.24 no.1
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• pp.59-64
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• 1992

Salted and then washed flounder muscles with salting levels of 10%, 15% and 20% were mixed with boiled foxtail millet and spices(radish, garlic, ginger and red pepper) and fermented at $15^{\circ}C$ for 7 days. The changes of taste constituents of fermented flounder Sikhae, such as sugars, free amino acids and 5'-nucleotides, were investigated. The content of fructose decreased significantly during Sikhae fermentation, but the content of mannitol that was not detected from raw material was estimated to be $6.26%{\sim}8.97%$ in Sikhae. The content of total free amino nitrogen in the 15% salted Sikhae was 290.6 mg% and the highest value with 53.4% of its extract nitrogen. It is believed that leucine, alanine, arginine, glutamine, isoleucine, valine, glutamic acid and lysine may play an important role as the taste constituents in Sikhae. The detected 5'-nucleotides were CMP, UMP, CTP, AMP, ADP and ATP and among them the nucleotide showing the hightest level irrespective of treatment was UMP estimated to be $761.0\;{\mu}g{\sim}849.0\;{\mu}g/g$. ATP and ADP were significantly decreased in Sikhae, but CMP and CTP were significantly increased in the 15% salted Sikhae compared with those of raw material.

• Korean journal of food and cookery science
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• v.13 no.1
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• pp.78-85
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• 1997

To determine the optimum coagulants concentrations for preparing soybean-curds, the transmittance of soybean-curd whey using spectrophotometer has been measured. The textural properties of soybean-curds were examined by texture analyzer and sensory evaluations. The general components, oligosaccharides and amino acids in soybean-curd wheys were analyzed. Protein patterns of soybean-curd wheys comparing with soyflour and soymilk were investigated. By texture analyzer, hardness, cohesiveness, springiness, and gumminess of Cacl$_2$ soybean-curd, MgCl$_2$ soybean-curd were higher than those of CaSO$_4$ soybean-curd and GDL soybean-curd. In the sensory evaluations, CaSO$_4$ soybean-curds and GDL soybean-curds were smoother and moister than others. Glutamic acid and aspartic acid were the first two abundant amino acids in three kinds of soybean-curd wheys, but arginine was the most abundant amino acid in GDL soybean-curd whey. Total sugar content of soybean-curd wheys were about 12-13 g/l, and the main sugars among 5 kinds of sugars were sucrose and raffinose. Electrophoresis using SDS-PAGE showed that glycinin and P-conglycinin, the main proteins of soybean appeared in soy flour and soymilk, and only low molecular weight subunits appeared in soybean-curd wheys.

• Journal of Mushroom
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• v.19 no.3
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• pp.216-224
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• 2021

This study analyzed food component characteristics and antioxidant activities in five kinds of domestic commercial shiitake mushrooms (Lentinula edodes). Moisture content (79.17-82.90 g/100 g) showed little difference, but there was a significant difference in crude protein content. Total mineral content showed a significant difference, and potassium (K) content was the highest. Total and essential amino acid contents were higher in mushroom A than in the other samples. Nonetheless, the ratios of essential amino acids, aspartic acid, and glutamic acid to total amino acids were similar in all samples. 𝛽-Glucan content was in the range of 10.28-5.68 g/100 g, exhibiting a significant difference. The color intensity and overall texture of the mushrooms showed no remarkable difference. Total phenol and flavonoid contents were in the range of 19.92-30.77 mg/100 g and 6.95-10.39 mg/100 g, respectively; the ratio of flavonoids to total phenols ranged from 31.53% to 38.21%. DPPH and ABTS radical scavenging activities were 74.92-79.04% and 80.47-84.97%, respectively, and showed little difference. However, the reducing power varied between 195.23 𝜇M and 317.85 𝜇M, displaying a significant difference in all samples. Therefore, this study observed similar trends in the food component characteristics and antioxidant activities of domestic commercial shiitake mushrooms.

• Journal of Life Science
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• v.19 no.12
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• pp.1777-1786
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• 2009

Thymosin ${\beta}4$, a small protein containing 43 amino acids, has multi-functional roles in cell physiology. It was first identified as a thymic maturation factor and recently has been shown to accelerate wound healing, hair growth, angiogenesis, tumor growth, and metastasis. It was also reported to play a key role in developing organs, including the nervous system and heart. Thymosin ${\beta}4$ induces the expression of vascular endothelial cell growth factor (VEGF), laminin-5, and other important biologically active genes. Using tissue microarray analysis, we investigated the expression patterns of thymosin ${\beta}4$ and VEGF in various normal human adult tissues. Thymosin ${\beta}4$ was highly expressed in the liver, pancreas, ductal epithelium of the salivary gland, and heart, and moderately expressed in the skin, lung, spleen, lymph node, thymus, ureter, and blood endothelial cells in both the lung and adrenal gland. The expression of VEGF generally co-localized with thymosin ${\beta}4$ and VEGF was highly expressed in the pancreas, ureter, mammary gland, liver, esophagus, and blood endothelial cells in both the lung and adrenal gland. These results suggest that thymosin ${\beta}4$ plays an important role in the function of various organs and since the expression pattern of thymosin ${\beta}4$ co-localized with VEGF, part of that function may be to induce or maintain angiogenesis.

• Food Science and Preservation
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• v.9 no.1
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• pp.28-35
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• 2002

This study was conducted to evaluate the quality characteristics of different soy sauces. The soybean sauces brewed tty the A. oryzae koji(SAO), M. pilosus-1 koji(SMP) and the mixture of 50% M. pilosus-1 koji(SAM) during 90 days fermentation. Total nitrogen contents of the SAM, SAP and SMP were 13.6%, 1.15% and 1.22%, respectively. Content of amino type nitrogen in SAM was 0.78%, and the content was higher than those of SAO and SMP. Total free amino acid contents of SAO, SMP and SAM were 533.8, 732.4 and 807.3 mg/100 mL. The highest contents of free, amino acids were glutamic acid(65.20 mg/100 mL) in SAG, alanine(101.42 mg/100mL) in SMP, glutamic acid(130.52 mg/100 mL) in SAM. The highest activities of pretense and ${\beta}$-amylase showed in SAM, and the lowest activities of ${\alpha}$-amylase and glucoamylase were in SAO and SMP respectively. Hue angle values showed 56.3 in SAO, 29.0 in SMP and 32.2 in SAM. Monacolin K contents, as inhibitor of cholesterol bio-synthesis were 6.21 $\mu\textrm{g}$/mL for SMP and 3.10 $\mu\textrm{g}$/mL for SAM, and the inhibitory activities of SMP ane SAM aginst HMG-CoA reductase were 21.5 md 10.2%, respectively. Sensory scores for color, flavor, savory taste and overall taste of SAM was higher than those of SAO and SMP.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.3
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• pp.292-301
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• 2010

Follicle-stimulating hormone (FSH) is a pituitary glycoprotein hormone that is encoded by separate alpha- and betasubunit genes. It plays a key role in stimulating and regulating ovarian follicular development and egg production in chicken. FSH signal transduction is mediated by the FSH receptor (FSHR) that exclusively interacts with the beta-subunit of FSH, but characterization of prokaryotic expression of the FSHb gene and its effect on the expression of the FSHR gene in local chickens have received very little attention. In the current study, the cDNA fragment of the FSHb gene from Dagu chicken was amplified using reverse transcription polymerase chain reaction (RT-PCR), and inserted into the pET-28a (+) vector to construct the pET-28a-FSHb plasmid. After expression of the plasmid in E. coli BL21 (DE3) under inducing conditions, the recombination protein, $FSH{\beta}$ subunit, was purified and injected into the experimental hens and the effect on the mRNA expression levels of the FSHR gene was investigated. Sequence comparison showed that the coding region of the FSHb gene in the local chicken shared 99%-100% homology to published nucleotides in chickens; only one synonymous nucleotide substitution was detected in the region. The encoded amino acids were completely identical with the reported sequence, which confirmed that the sequences of the chicken FSHb gene and the peptides of the $FSH{\beta}$ subunit are highly conserved. This may be due to the critical role of the normal function of the FSHb gene in hormonal specificity and regulation of reproduction. The results of gene expression revealed that a recombinant protein with a molecular weight of about 19 kDa was efficiently expressed and it was identified by Western blotting analysis. After administration of the purified $FSH{\beta}$ protein, significantly higher expression levels were demonstrated in uterus, ovary and oviduct samples (p<0.05). These observations suggested that the expressed $FSH{\beta}$ protein possesses biological activity, and has a potential role in regulation of reproductive physiology in chickens.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.410-416
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• 2008

The gene SfXyn10, which encodes a protease-resistant xylanase, was isolated using colony PCR screening from a genomic library of a feather-degrading bacterial strain Streptomyces fradiae var. k11. The full-length gene consists of 1,437bp and encodes 479 amino acids, which includes 41 residues of a putative signal peptide at its N terminus. The amino acid sequence shares the highest similarity (80%) to the endo-1,4-${\beta}$-xylanase from Streptomyces coelicolor A3, which belongs to the glycoside hydrolase family 10. The gene fragment encoding the mature xylanase was expressed in Escherichia coli BL21 (DE3). The recombinant protein was purified to homogeneity by acetone precipitation and anion-exchange chromatography, and subsequently characterized. The optimal pH and temperature for the purified recombinant enzyme were 7.8 and $60^{\circ}C$, respectively. The enzyme showed stability over a pH range of 4.0-10.0. The kinetic values on oat spelt xylan and birchwood xylan substrates were also determined. The enzyme activity was enhanced by $Fe^{2+}$ and strongly inhibited by $Hg^{2+}$ and SDS. The enzyme also showed resistance to neutral and alkaline proteases. Therefore, these characteristics suggest that SfXyn10 could be an important candidate for protease-resistant mechanistic research and has potential applications in the food industry, cotton scouring, and improving animal nutrition.

• The Korean Journal of Food And Nutrition
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• v.28 no.3
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• pp.404-414
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• 2015

Taurine is one of the most abundant free ${\beta}$-amino acids in the human body that accounts for 0.1% of the human body weight. It has a sulfonic acid group in place of the more common carboxylic acid group. Mollusks and meat are the major dietary source of taurine, and mother's milks also include high levels of this amino acid. The leukocytes, heart, muscle, retina, kidney, bone, and brain contain more taurine than other organs. Furthermore, taurine can be synthesized in the brain and liver from cysteine. There are no side effects of excessive taurine intake in humans; however, in case of taurine deficiency, retinal abnormalities, reduced plasma taurine concentration, and other abnormalities may occur. Taurine enters the cell via a cell membrane receptor. It is excreted in the urine (approximately 95%) and feces (approximately 5%). Taurine has a number of features and functions, including conjugation with bile acid, reduction of blood cholesterol and triglyceride levels, promotion of neuron cell differentiation and growth, antioxidant effects, maintenance of cell membrane stability, retinal development, energy generation, depressant effects, regulation of calcium level, muscle contraction and relaxation, bone formation, anti-inflammatory effects, anti-cancer and anti-atherogenic effects, and osmotic pressure control. However, the properties, functions, and effects of taurine require further studies in future.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.776-783
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• 2018

The agarase gene gaa16a was identified from a draft genome sequence of Gilvimarinus agarilyticus JEA5, an agar-utilizing marine bacterium. Recently, three agarase-producing bacteria, G. chinensis, G. polysaccharolyticus, and G. agarilyticus, in the genus Gilvimarinus were reported. However, there have been no reports of the molecular characteristics and biochemical properties of these agarases. In this study, we analyzed the molecular characteristics and biochemical properties of agarases in Gilvimarinus. Gaa16A comprised a 1,323-bp open reading frame encoding 441 amino acids. The predicted molecular mass and isoelectric point were 49 kDa and 4.9, respectively. The amino acid sequence of Gaa16A showed features typical of glycosyl hydrolase family 16 (GH16) ${\beta}$-agarases, including a GH16 domain, carbohydrate-binding region (RICIN domain), and signal peptide. Recombinant Gaa16A (excluding the signal peptide and carbohydrate-binding region, rGaa16A) was expressed as a fused protein with maltose-binding protein at its N-terminus in Escherichia coli. rGaa16A had maximum activity at $55^{\circ}C$ and pH 7.0 and 103 U/mg of specific activity in the presence of 2.5 mM $CaCl_2$. The enzyme hydrolyzed agarose to yield neoagarotetraose as the main product. This enzyme may be useful for industrial production of functional neoagaro-oligosaccharides.