• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.37-42
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• 2023

Neutral and non-essential amino acid, glutamine (Gln), plays an essential role in supplying nitrogen to all the amino acids and nucleotides in the mammalian body. Gln is also the most important carbon source that provides intermediates for gluconeogenesis and fatty acid synthesis and supplements the tricarboxylic acid cycle in fast-growing cancer cells. Among the known 14 Gln transporter genes, soluted carrier family 1 member 5 (SLC1A5) has been reported to be closely associated with cancer cell growth. Three variants (v1, v2, and v3) have been derived from SLC1A5. Here, we established a heterologous gene expression system for the active form of human SLC1A5 variant-2 (hSLC1A5v2) in Escherichia coli. v2 is the smallest variant that has not yet been studied. Four expression systems were investigated: pBAD, pCold, pET, and pQE. We also addressed the problem of codon usage bias. Although pCold and pET overexpressed hSLC1A5v2 in E. coli, they were functionally inactive. hSLC1A5v2 using the pBAD system was able to catalyze the successful transport of Gln, even if it was not highly expressed. Initial activity of hSLC1A5v2 for [¹⁴C] Gln uptake in E. coli reached up to 6.73 μmole·min^-1·gDW^-1 when the cell was induced with 80 mM L-arabinose. In this study, we demonstrated a heterologous expression system for the human membrane protein, SLC1A5, in E. coli. Our results can be used for the functional comparison of SLC1A5 variants (v1, v2, and v3) in future studies, to facilitae the developement of SLC1A5 inhibitors as effective anticancer drugs.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.404-413
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• 1999

Methanopyrus kandleri is a hyperthermophilic methanogen that represents one of the most heat-resistant organisms: the maximum growth temperature of M. kandleri is $110^{\circ}C$. A random sequence analysis of the genomic DNA of M. kandleri has been performed to obtain genomic information. More than 200 unique sequence tags were obtained and compared with the sequences in the GenBank and PIR databases. About 30% of the analyzed tags showed strong sequence similarity to previously identified genes involved in various cellular processes such as biosynthesis, transport, methanogenesis, or metabolism. When statistics relating to the frequency of codons were examined, the sequenced open reading frames showed highly biased codon usage and a high content of charged amino acids. Among the identified genes, a homologue of the catalytic subunit of carbon monoxide dehydrogenase (CODH) that reduces $CO_2$ to CO was cloned and sequenced in order to examine its detailed gene structure. The cloned gene includes consensus promoters. The amino acid sequence of the cloned gene shows a strong homology with the CODH genes from methanogenic Archaea, especially in the presumed binding sites for Fe-S centers.

• Korean journal of food and cookery science
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• v.4 no.1
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• pp.33-40
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• 1988

This study was performed to analyze flavor components of foods, that is, total free amino acids, free glutamic acid(constituent of MSG) and nucleotide relating substances. Twenty-five foods popular to Korean were selected and prepared according to recipes of several cooking books. The results were as follows; In contents of total free amino acids, free glutamic acid and total nucleotide relating substances, similar Patterns were shown. The foods which their major food stuffs were meat, fish and marine products and which a large amount of soy sauce were added to, tended to show high contents. of those On the other hand, although major foodstuffs had relatively high contents of those, foods added other many sub-foodstuffs had shown intermediate contents of those. Soups and watery noodles had low contents of those because of their large water amount. Especially, foods made of vegetables without addition of soy sauce showed low content of IMP. In foods various ratios of free glutamic acid to IMP were calculated. Thus, the proper usage of the chemical seasoning containing nucleotide at various contents should be considered for efficient flavor enhancing effect.

• Journal of Microbiology and Biotechnology
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• v.22 no.9
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• pp.1202-1207
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• 2012

A gene, ClCDA, encoding chitin deacetylase from Colletotrichum lindemuthianum, was optimized according to the codon usage bias of Pichia pastoris and synthesized in vitro by overlap extension PCR. It was secretorily expressed in P. pastoris GS115 using the constitutive expression vector pHMB905A. The expression level reached the highest with 110 mg/l culture supernatant after 72 h of methanol induction, which comprised 77.27 U/mg chitin deacetylase activity. SDS-PAGE, mass spectrometry, and deglycosylation assays demonstrated that partial recombinant protein was glycosylated with an apparent molecular mass of 33 kDa. The amino acid sequences of recombinant proteins were confirmed by mass spectrometry.

• Journal of the Korean Society of Food Culture
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• v.32 no.1
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• pp.52-57
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• 2017

The feasibility of reduction of sodium intake using sun-dried salt and monosodium glutamate (MSG) was studied. Preference test was performed to evaluate the sensory properties of bean-sprout soup and vegetable rice porridge soup. Sun-dried salt and MSG might be a partial substitute for refined salt. There was a significant difference in salt taste strength between sun-dried salt and refined salt. Sun-dried salts 0.45% with MSG 0.07% resulted in the highest taste preference compared to that of sun-dried salts 0.60% without MSG in bean-sprout soup, which resulted in 23.9% reduction of sodium intake. Sun-dried salts 0.38% with MSG 0.04% resulted in the highest taste preference compared to sun-dried salts 0.53% without MSG in vegetable rice porridge soup, which resulted in 25.4% reduction of sodium intake. There seemed to be a synergistic effect on reduced usage of sodium salt when MSG was used in vegetable rice porridge and bean-sprout soup with sun-dried salt.

• Journal of Microbiology
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• v.38 no.2
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• pp.80-87
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• 2000

The nucleotide sequence of the luxC gene coding for lux-specific fatty acyl-CoA reductase and the upstream DNA (325bp)of the structural gene from bioluminescent bacterium, Photobacterium phosphoreum, has been deternubed. An open reading frame extending for more than 20 codons in 325 bp DNA upstream of luxC was not present in both directions. The lux gene can be translated into a polypeptide of 54 kDa and the amino acid sequences of lux specific reductases of P. phosphoreum shares 80, 65, 58, and 62% identity with those of the Photobacterium leiognathi, Vibrio fischeri, Vibrio harveyi, and Xehnorhabdus luminescenens reductases, respectively. Analyses of codon usage, showing that a high frequency (2.3%) of the isoleucine codon, AUA, in the luxC gene compared to that found in Escherichia coli genes (0.2%) and its absence in the luxA and B genes, suggested that the AUA codon may play a modulator role in the expression of lux gene in E. coli. The structural genes (luxC, D, A, B, E) of the P. phosphoreum coding for luciferase (${\alpha}$,${\beta}$) and fatty acid reductase (r, s, t) polypeptides can be expressed exclusively in E. coli under the T7 phage RNA polymerase/promoter system and identificationof the [35S]methionine labelled polypeptide products. The degree of expression of lux genes in analyses of codon usage. High expression of the luxC gene could only be accomplished in a mutant E. coli 43R. Even in crude extracts, the acylated acyl-CoA reductase intermediate as well as acyl-CoA reductrase activities could be readily detected.

• Journal of Dairy Science and Biotechnology
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• v.17 no.1
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• pp.16-31
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• 1999

Milk and milk products, especially the cow's milk and cheese, have been used since the ancient time. Because they contains almost all kinds of nutrients that are necessary for human beings except for iron, n-3 fatty acid, and vitamin C. Milk is an excellent dietary source of protein, calcium and phosphorus. The biological value of milk protein is as high as those of red meat and eggs. So cheese, a food processed from concentrated milk protein, is highly recommended food for the patient of diabetes mellitus. Because the major form of milk lipids is n-6 fatty acid, milk and milk products may not be a good food for the patients of cardiovascular disease. But the nutritional quality of milk lipids cannot be inferior to those of margarine, fish oil, and vegetable oil. Milk has been produced commercially since 1936 in Korea. The most popular milk product is a drink milk now in Korea. But according to the change of dietary pattern the consumption of yoghurt and cheese has been enormously increased during the last 20 years. As the soy sauce, tofu, and soy been paste have been the fundamental seasoning and source of protein in Korea, milk and cheese have consisted the essential flavor of western cuisine. But the basic idea for the usage of protein, peptides, and amino acids are the same. We found that milk and milk products can be nicely added in many Korean dishes such as Juk, Mandoo, Jeon, and Bindeatuk for the diversity of traditional flavor.

• Journal of Life Science
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• v.9 no.1
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• pp.84-89
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• 1999

To determine phylogenetic relatedness of four silk-producing silkmoths (B. mori, B. mandarina, A. yamamai and A. pernyi), internal coding region of arylphorin which is a storage protein in hemolymph protein of insects were amplified by polymerase chain reaction and then sequenced and compared each other. The nucleotide composition was biased toward adenine and thymine(59% A+T) and a strong bias for use of C in the third position of codons was found for Phe and Tyr. Together TTC(Phe) and TAC(Tyr) account for about 16.8% (10 for TTC and 8 for TAC) of all codon usage. The nucleotide similarity of arylphorin gene from B. mori showed 99%, 98% and 97% homology with those of B. mandarina, A. yamamai and A. pernyi, respectively. Also, the nucleotide sequence of arylphorin gene from B. mandarina showed 98% and 97% homology with those of A. yamamai and A.pernyi, respectively. Between A. yamamai and A. pernyi, the sequence homology was 97%. The deduced amino acid sequences in B. mori, B. mandarina and A. yamamai showed almost 99% homology. Although the aryphorin gene provided insufficient variability among the four insect species, A UPGMA tree is generated that supported the monophyly of silk-producing insects, with M. sexta placed basal to it. It is suggest that silk-producing insects have a close relationship and a homogeneous genetic background from comparison with those of other insects.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.192-197
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• 2011

Rice spent water (RSW) is generated when rice is rinsed before cooking. RSW has been discarded into sewerages due to its low usage in our daily life and become a major domestic wastewater for many years. But RSW can be used as a value-added resource because it contains various beneficial bioactive components. Therefore, fermented rice spent water (FRSW) has been already produced in our previous value-added fermentation process. In this study, proximate compositions and contents of other typical fermentation products were compared between RSW and FRSW. Both RSW and FRSW contain approximately 99.3% moisture and 0.7% total solids. Compared to those of RSW on a dry basis, carbohydrate content of FRSW was decreased by 44.8% and crude protein, lipid, and ash contents of FRSW were increased by 16.4%, 18.8%, and 36.6%, respectively. In addition, starch granules of RSW were intact as those of rice flour were, but those of FRSW were not. RSW did not have lactic acid, but FRSW had 212.13 and 181.25 g/kg D- and L-lactic acid, respectively. Free amino and ammoniacal nitrogen contents of FRSW were 12 and 7 times higher than those of RSW, respectively. Lactic acid, free amino, and ammonical nitrogen contents were considered to be increased in FRSW because carbohydrates could be disintegrated into lactic acids and proteins into free amino or ammoniacal nitrogens during the fermentation process.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.12
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• pp.1946-1955
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• 2018

Objective: This study was conducted to evaluate the effect of keratinase (KE) on the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AA) in rice bran, cottonseed meal (CSM), rapeseed meal (RSM), corn distillers dried grains with solubles (DDGS), and peanut meal (PNM). Methods: Twelve crossbred barrows (Duroc${\times}$Landrace${\times}$Yorkshire, $50.5{\pm}1.4kg$ body weight [BW]) fitted with T-cannulas at the terminal ileum were allotted to a $12{\times}6$ Youden Square design with 12 diets and 6 periods. The treatment diets included rice bran, CSM, RSM, corn DDGS, PNM, or corn-soybean meal (cSBM) supplemented with 0.05% KE or not. Diets were given to pigs at a level of 3% BW in two equal meals. The endogenous AA losses were the mean results of three previously experiments determined by a same nitrogen-free diet fed to pigs. Pigs had free access to water during the experiment. Results: The KE supplementation improved (p<0.05) the AID and SID of Met, Thr, Val, Asp, Cys, and Tyr in rice bran. Inclusion of KE increased (p<0.05) the AID and SID of Met and Val in CSM. The KE supplementation decreased (p<0.05) the AID and SID of His in RSM and all measured AA except for Arg, Met, Trp, Val, Gly, and Pro in corn DDGS. There was an increase (p<0.05) in AID and SID of Leu, Ile, Met, Ala, Cys, Ser, and Tyr in PNM supplemented with KE compared with that without KE. Inclusion of KE increased (p<0.05) the AID and SID of crude protein, Leu, Ile, Phe, Thr, Asp, and Ser in cSBM. Conclusion: This study indicated that KE had different effects on ileal AA digestibility of feedstuffs for growing pigs, which can give some usage directions of KE in swine feed containing those detected feedstuffs.