• Food Science and Biotechnology
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• v.17 no.1
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• pp.114-117
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• 2008

Chelating agents to sand lance fish sauce for the prevention of precipitate formation were applied. The precipitates consisted of crude protein (74.4%), ash (18.7%), and other components (6.9%). Sand lance sauce was mainly composed of glutamic acid (3.69 mg/g), alanine (2.96 mg/g), and lysine (2.64 mg/g). However, there was an increase in the amount of hydrophobic amino acids, phenylalanine, isoleucine, and leucine, in the precipitates. Sodium ions were not detected in the precipitate; rather, the main elements were Mg ($1.98{\times}10^4\;{\mu}g/g)$, K ($1.36{\times}10^4\;{\mu}g/g)$, and Ca ($6.66{\times}10^2\;{\mu}g/g)$. In HPLC analysis, fish sauce was composed of 2 main peaks with molecular weights of 85.5 and 528.4 Da, respectively. However, the precipitate contained one peak with a molecular weight of 1,513.5 Da. The addition of 0.2% malic acid and citric acid caused 55 and 70% prevention of the precipitate, respectively. Citric acid was the most effective chelating agent and efficiently prevented precipitation in the fish sauce.

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.79-85
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• 1996

By using a T7 expression system, a large amount of Bacillus stearothermophilus endo-xylanase A (XynA) could be produced in Escherichia coli cells. The overproduced enzyme formed inclusion bodies, and so the protein could be more easily purified to homogeneity. The molecular weight of the purified enzyme was estimated to be 22 kDa by SDS-polyacrylamide gel electrophoresis and 43 kDa by Sephacryl S-200 gel filtration, suggesting that the native enzyme was a homodimer. The pI value was determined to be 8.4. The Michaelis constants for birchwood xylan and oat spelts xylan were calculated to be 3.83 mg/ml and 5.03 mg/ml, respectively, and the $V_{max}$ max/ values for both xylans were 2.86 $\mu mole$/min. The purified enzyme was most active at $55^{\circ}C$ and pH 8.0, and stable up to $60^{\circ}C$ and in the near neutral pH range. From the zymogram, Bacillus stearothermophilus was found to have at least three xylanases and the purified one was the smallest among them.

• Parasites, Hosts and Diseases
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• v.55 no.5
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• pp.473-480
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• 2017

Plasmodium vivax merozoite surface protein-1 (PvMSP1) gene codes for a major malaria vaccine candidate antigen. However, its polymorphic nature represents an obstacle to the design of a protective vaccine. In this study, we analyzed the genetic polymorphism and natural selection of the C-terminal 42 kDa fragment within PvMSP1 gene ($PvMSP1_{42}$) from 77 P. vivax isolates, collected from imported cases of China-Myanmar border (CMB) areas in Yunnan province and the inland cases from Anhui, Yunnan, and Zhejiang province in China during 2009-2012. Totally, 41 haplotypes were identified and 30 of them were new haplotypes. The differences between the rates of non-synonymous and synonymous mutations suggest that $PvMSP1_{42}$ has evolved under natural selection, and a high selective pressure preferentially acted on regions identified of $PvMSP1_{33}$. Our results also demonstrated that $PvMSP1_{42}$ of P. vivax isolates collected on China-Myanmar border areas display higher genetic polymorphisms than those collected from inland of China. Such results have significant implications for understanding the dynamic of the P. vivax population and may be useful information towards China malaria elimination campaign strategies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.112-122
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• 2020

This study investigated some enzymatic properties and bitterness improvement of an aminopeptidase retentate fraction (ARF) from common squid Todarodes pacificus hepatopancreas extract (HPE), obtained by ultrafiltration with a 10 kDa molecular weight cut off membrane. Endoprotease and aminopeptidase (AP) activity, and the purity of the ARF (>10 kDa) increased by 6.69-18.11 U/mg and 1.5-2.6 fold, respectively, compared to HPE (2.63-9.37 U/mg). The AP activity toward LeuPNA was stable at 20-55℃ and pH 5-9, but decreased slightly with increasing concentration of NaCl in the reaction mixture. The ARF was the most active MetPNA and preferentially hydrolyzed Glu, Leu and AlaPNA. The bitterness tryptic casein hydrolysates (BTCHs) were treated with ARF, and the bitterness of ARF-BTCHs significantly decreased with increasing amounts of released amino acids Ala, Val, Met, Ile and Leu, which show strong correlations with bitterness. Therefore, the ARF of T. pacificus HPE obtained by ultrafiltration may have a considerable potential for application in protein hydrolysis and appears to be ideally suited to the purpose of lowing bitterness in protein hydrolysates.

• Korean Journal of Microbiology
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• v.45 no.3
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• pp.257-262
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• 2009

Carboxymethyl celluase (cellulase) was purified from cell-free extract of the recombinant Escherichia coli carrying a Bacillus licheniformis WL-12 cellulase gene by DEAE-Sepharose and phenyl-Sepharose column chromatography with specific activity of 163 U/mg protein. The molecular mass of the purified enzyme was estimated to be approximately 49.5 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme had a pH optimum at 5.5 and a temperature optimum at $55^{\circ}C$. The activity of the enzyme was completely inhibited by SDS (5 mM), and slightly enhanced by $Cu^{2+}$ (5 mM). The cellulase was active on CMC, konjac, barely glucan and lichenan, while it did not exhibit activity towards xylan, locust bean gum, and p-nitrophenyl-$\beta$-glucopyranoside. The predominant products resulting from the cellulase hydrolysis were cellobiose and cellotriose for cellooligosaccharides including cellotriose, cellotetraose and cellopentaose. The enzyme could hydrolyze cellooligosaccharides larger than cellobiose.

• Analytical Science and Technology
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• v.8 no.2
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• pp.117-124
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• 1995

To Purify hemoproteins showing from 218nm absorbance, crude liver extract of human with hepatocirrhosis was treated with Triton N-101. Hemoproteins were purified by modification of Mohamed's method. This crude extract was applied to Octyl-Sepharose CL-4B column and the step elution was performed with 0.06% Lubrol PX and 0.25% Lubrol PX. The absorption of effluents were examined at 418nm and two peaks were appeared(Fig. 2). Hemoproteins were purified from Hyydroxyapatite and DEAE-Sephadex A-25 columns which the first peak was applied to(Fig. 3, 4). In death with suddenly, purified hemoproteins with 62 and 45kDa were obtained from 12.5% SDS-PAGE. In death with hepatocirrhosis, purified hemoprotein with 54kDa was obtainded from 12.5% SDS-PAGE(Fig. 5). Cytochrome P450 was purified to a specific content of 20.8nmol/mg protein with a recovery of about 4.1%. Absorbance maximum of these hemoproteins were 446nm at UV spectruum(Fig. 6).

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.241-246
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• 2002

A gene coding for endo-$\beta$-1,3-1,4-glucanase of Bacillus circulans was subcloned into Escherichia coli Ml5 using pQE30 as an expression vector. Endo-$\beta$-1,3-1,4-glucanase produced by the recombinant expression plas-mid pLQ43 was intactly purified to a single protein through a nickel-nitrilotriacetic acid (Ni-NTA) metal-affinity chromatography method. The molecular mass of the purified enzyme was estimated to be 28 kDa by SDS-PAGE. The optimum pH and temperature of the enzyme activity were pH 6.8 and $60^{\circ}C$, respectively. This enzyme was fairly stable in the pH ranging 5.5~7.5 and at the temperatures lower than $55^{\circ}C$. The enzyme appeared to be sensitive to most of the metal ions, especially to $Hg^{2＋$, and also to methanol, ethanol, isopropanol or 1-butanol at a concentration of 10%(v/v).

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.474-482
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• 2004

The $\alpha$-L-arabinofuranosidase (Arfase) gene of Bacillus stearothermophilus No. 236 was cloned and sequenced. The ORF of the gene, designated arfA, encoded a 507 -residue polypeptide with calculated molecular mass of 57 kDa. The Arfase produced by a recombinant Escherichia coli strain containing the arfA gene was purified to apparent homogeneity and characterized. The molecular mass of the Arfase determined by SDS-PAGE was 60 kDa. However, according to gel filtration, it was estimated to be approximately 190 kDa. These results indicated that the functional form of the Arfase is trimeric. The optimal pH and temperature for the enzyme activity were pH 6.5 and $55^{\circ}C$, respectively. The half-life of the enzyme at $60^{\circ}C$ was about 6 h. Kinetic experiments at $45^{\circ}C$ with pNPM (p-nitrophenyl $\alpha$-L-arabinofuranoside) as a substrate gave the $K_m and V_{max}$ values of 1.19 mM and 26.1 U/ mg, respectively. When the enzyme was combined with Bacillus stearothermophilus No. 236 endoxylanase and $\beta$-xylosidase, it hydrolyzed arabinoxylan into L-arabinose and xylose more efficiently than Arfase alone. This synergistic effect suggested that the complete hydrolysis of xylan with large amounts of arabinose side chains required Arfase as well as endoxylanase and $\beta$-xylosidase.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1321-1324
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• 2012

Background: DNA polymerase beta ($pol{\beta}$) is a key enzyme in the base excision repair pathway. It is 39kDa protein, with two subunits, one large subunit of 31 kDa having catalytic activity between exon V to exon XIV, and an 8 kDa smaller subunit having single strand DNA binding activity. Exons V to VII have double strand DNA binding activity, whereas exons VIII to XI account for the nucleotidyl transferase activity and exons XII to XIV the dNTP selection activity. Aim: To examine the association between $pol{\beta}$ polymorphisms and the risk of ovarian cancer, the present case control study was performed using 152 cancer samples and non-metastatic normal samples from the same patients. In this study, mutational analysis of $pol{\beta}$ genomic DNA was undertaken using primers from exons IX to XIV - the portion having catalytic activity. Results: We detected alteration in DNA polymerase beta by SSCP. Two specific heterozygous point mutations of $pol{\beta}$ were identified in Exon 9:486, A->C (polymorphism 1; 11.18%) and in Exon 11:676, A->C (polymorphism 2; 9.86%). The correlation study involving polymorphism 1 and 4 types of tissue showed a significant correlation between mucinous type with a Pearson correlation value of 4.03 (p=0.04). The association among polymorphism 2 with serous type and stage IV together have shown Pearson ${\chi}^2$ value of 3.28 with likelihood ratio of 4.4 (p=0.07) with OR =2.08 (0.3-14.55). This indicates that there is a tendency of correlation among polymorphism 2, serous type and stage IV, indicating a risk factor for ovarian cancer. Conclusion: Hence, the results indicate that there is a tendency for $pol{\beta}$ polymorphisms being a risk factor for ovarian carcinogenesis in India.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1629-1635
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• 2016

A novel bacteriophage, PBES 02, infecting Cronobacter sakazakii was isolated and characterized. It has a spherical head of 90 nm in diameter and a tail of 130 nm in length, and belongs to Myoviridae as observed under a transmission electron microscope. The major virion protein appears to be 38 kilodaltons (kDa) in size. The latent period of PBES 02 is 30 min and the burst size is 250. Infectivity of the phage remained intact after exposure to temperatures ranging from 4℃ to 55℃ for 1 h. It was also stable after exposure to pHs ranging from 6 to 10 for 1 h. The phage effectively removed contaminating Cronobacter sakazakii from broth infant formula. PBES 02 has a double-stranded DNA genome of 149,732 bases. Its GC ratio is 50.7%. Sequence analysis revealed that PBES 02 has 299 open reading frames (ORFs) and 14 tRNA genes. Thirty-nine ORFs were annotated, including 24 related to replication and regulation functions, 10 related to structural proteins, and 5 related to DNA packaging. The genome of PBES 02 is closely related to that of two other C. sakazakii phages, CR3 and CR8. Comparison of DNA sequences of genes encoding the major capsid protein revealed a wide geographical distribution of related phages over Asia, Europe, and America.