• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.439-446
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• 2020

Two Bacillus strains, K3 and K208, both demonstrating strong fibrinolytic activities were isolated from Kimchi, a traditional Korean preparation of fermented vegetables. Isolates were subjected to various molecular biology based identification methods including RAPD-PCR and identified as B. subtilis and B. velezensis, respectively. Tryptic soy broth (TSB) was found to best maintain both the growth and the fibrinolytic activity of these strains. Culture supernatants were analyzed by SDS-PAGE and fibrin zymography, and the results indicate that a 40 and 27 kDa band seem to be responsible for the fibrinolytic activities of these two isolates and the 27 kDa band was subsequently identified as the mature form of AprE, the major fibrinolytic enzyme. Thus the aprE genes were cloned and the translated amino acid sequences demonstrated 99.3% identity with each other, and 86.5% identity with BsfA, a fibrinolytic enzyme from B. subtilis ZA400 also isolated from Kimchi, and AprE2, a fibrinolytic enzyme from B. subtilis CH3-5 isolated from Cheonggukjang, a traditional Korean fermented soy. Given this B. subtilis K3 and B. velezensis K208 may be promising starter cultures in the production of fermented foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1287-1293
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• 2008

This study investigated quality changes and functions of low-molecular soymilk according to hydrolysis time (30, 60, and 90 minutes). According to the results, pH of hydrolyzed groups were lower than that of the control group but it did not show a large difference according to hydrolysis time while sugar content was reduced with longer hydrolysis time. Although degree of hydrolysis and calcium tolerance increased with longer hydrolysis time, there was not a significant difference according to the time. Among free sugars, contents of glucose and fructose grew while those of sucrose and maltose tended to decline with time. Total free sugar content was the largest with 60 minutes of hydrolysis time recording 827.65 mg%. Total amino acid content was also the highest with hydrolyzed for 60 minutes recording 85.80 mg% and those of all hydrolyzed groups were higher than that of the control group. In addition, the content of essential amino acid increased significantly with time. In SDS-PAGE, checked for the tendency of becoming low molecules, molecular weights were found to be 33 kDa or less kDa in all hydrolyzed groups. When functional characteristics of soymilk such as electron donating, superoxide radical scavenging and ACE inhibitory activities were compared, longer hydrolysis time led to higher activities. From these results, overall quality of low molecular soymilk was superior when hydrolyzed for 60 minutes and the findings should be viable in the development of various types of functionally strengthened low-molecular soymilk in the future.

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1221-1228
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• 2013

Two lipase genes (bpl1 and bpl3) from Antarctic Bacillus pumilus strains were expressed in Bacillus subtilis. Both recombinant lipases BPL1 and BPL2 were secreted to the culture medium and their activities reached 3.5 U/ml and 5.0 U/ml, respectively. Their molecular masses apparent using SDS-PAGE were 23 kDa for BPL1 and 19 kDa for BPL3. Both lipases were purified to homogeneity using ammonium sulfate precipitation and HiTrap SP FF column and Superose 12 column chromatographies. The final specific activities were estimated to be 328 U/mg for BPL1 and 310 U/mg for BPL3. Both lipases displayed an optimum temperature of $35^{\circ}C$, similar to other mesophilic enzymes. However, they maintained as much as 70% and 80% of the maximum activities at $10^{\circ}C$. Accordingly, their calculated activation energy at a temperature range of $10-35^{\circ}C$ was 5.32 kcal/mol for BPL1 and 4.26 kcal/mol for BPL3, typical of cold-adapted enzymes. The optimum pH of BPL1 and BPL3 was 8.5 and 8.0, respectively, and they were quite stable at pH 7.0-11.0, showing their strong alkaline tolerance. Both lipases had a preference toward medium chain length ($C_6-C_{10}$) fatty acid substrates. These results indicate the potential for the two Antarctic B. pumilus lipases as catalysts in bioorganic synthesis, food, and detergent industries.

• Food Science of Animal Resources
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• v.34 no.2
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• pp.151-157
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• 2014

This study investigated the effects of three proteases (trypsin, pepsin and chymotrypsin) on the hydrolysis efficiency of porcine placenta and the molecular weight (Mw) distributions of the placental hydrolysates. Because placenta was made up of insoluble collagen, the placenta was gelatinized by applying thermal treatment at $90^{\circ}C$ for 1 h and used as the sample. The placental hydrolyzing activities of the enzymes at varying concentrations and incubation times were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel permeation chromatography (GPC). Based on the SDS-PAGE, the best placental hydrolysis efficiency was observed in trypsin treatments where all peptide bands disappeared after 1 h of incubation as compared to 6 h of chymotrypsin. Pepsin hardly hydrolyzed the placenta as compared to the other two enzymes. The Mw distribution revealed that the trypsin produced placental peptides with Mw of 106 and 500 Da. Peptides produced by chymotrypsin exhibited broad ranges of Mw distribution (1-20 kDa), while the pepsin treatment showed Mw greater than 7 kDa. For comparisons of pre-treatments, the subcritical water processing (37.5 MPa and $200^{\circ}C$) of raw placenta improved the efficiency of tryptic digestions to a greater level than that of a preheating treatment ($90^{\circ}C$ for 1 h). Consequently, subcritical water processing followed by enzymatic digestions has the potential of an advanced collagen hydrolysis technique.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.271-279
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• 2015

Lactoferrin (LF) is a multifunctional, iron-binding glycoprotein found in physiological secretions of mammals. LF shows antibacterial, antiviral and antifungal activities. In the present study, a gene encoding the N-terminal lobe of human lactoferrin (hLF) was isolated, cloned and expressed in methylotrophic yeast, Pichia pastoris. The recombinant hLF-N (rhLF-N) protein was secreted into the culture medium at the level of $458{\mu}g/ml$ in 3 L fermentor. The size of purified hLF-N was estimated as 35 kDa when analyzed by SDS-PAGE and western blotting. The rhLF-N was further confirmed by immunodiffusion using the anti-hLF polyclonal antibody. The expression profile analysis by qRT-PCR showed that the relative mRNA expression of rhLF-N was maximal after 2-3 days of methanol induction and reduced gradually at 4 days. The purified rhLF-N showed broad antibacterial activities against the pathogens such as Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, Burkholderia cepacia, and Salmonella typhimurium. However, rhLF-N showed relatively lower activity when compared to peptides derived from LF. In spite of this weak activity, the rhLF-N expressed in P. pastoris might be more advantageous for the industrial application, because rhLF-N is secreted into the culture medium and the production can also be increased by optimization of culture conditions.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.131-137
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• 2021

This study aimed at isolating lactic acid bacteria with anti-MRSA (methicillin-resistant Staphylococcus aureus) bacteriocin activity from fermented shrimp. We selected three strains, named Weissella sp. S1, S2, and S3, using analysis based on 16S rRNA gene sequences. All strains showed appropriate growth in an MRS medium containing 5% (w/v) NaCl and showed antibacterial activities against Bacillus cereus, Escherichia coli, Staphylococcus aureus, and MRSA. The strains exhibited similar growth rates at 0-5% NaCl, with approximate reduction in growth rate observed at 9% NaCl. Weissella sp. S1, S2, and S3 exhibited maximum growth rates at pH 7, 9, and 8, respectively. The crude bacteriocin was prepared from Weissella sp. S3 and subjected to characterization. The remaining activities after 30 min of exposure at each temperature were 100%, beyond 75%, and 49% at 4℃ and 37℃, 50℃ and 70℃, and 100℃, respectively. The remaining activities after 24 h of exposure at each pH were 100%, 75%, and 49% at pH 3 and 5, 7 and 9, and 10, respectively. Use of 50% (v/v) ethanol or isopropanol treatment did not diminish the antibacterial activity of the bacteriocin, while the 50% (v/v) hexane treatment reduced the activity by 51%. The molecular weight of the bacteriocin was nearly 6 kDa that was quantified using tricine-SDS-PAGE. Our findings suggest that Weissella sp. S3 may be considered a probiotic and useful source of antimicrobial substances in the development of bio-preservatives for food or in MRSA treatment.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.275-282
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• 2005

A chitinolytic bacterium, Chromobacterium sp. strain C-61, was found strongly antagonistic to Rhizoctonia solani, a causal agent of damping-off of eggplant. In this study, the biocontrol activity and enzymatic characteristics of strain C-61 were compared with its four Tn5 insertion mutants (C61-A, -B, -C, and -D) that had lower chitinolytic ability. The chitinase activity of a 2-day old culture was about $76\%,\;49\%\;and\;6\%$ level in C61-A, C61-B and in C61-C, respectively, compared with that of strain C-61. The $\beta-N-acetylhexosaminidase$(Nahase) activity was little detected in strain C-61 but increased largely in C-61A, C61-B and C61-C. Activities of chitinase and Nahase appeared to be negatively correlated in these strains. Another mutant, C-61D, produced no detectable extracellular chitinase and Nahase. The in vitro and in vivo biocontrol activities of strain C-61 and its mutants were closely related to their ability to produce chitinase but not Nahase. No significant differences in population densities between strain C-61 and its mutants were observed in soil around eggplant roots. The results of SDS-PAGE and isoelectrofocusing showed that a major chitinase of strain C-61 is 54-kDa with pI of approximately 8.5. This study provides evidence that the biocontrol activity of Chromobacterium sp. strain C-61 against Rhizoctonia solani depends on the ability to produce chitinase with molecular weight of 54-kDa and pI of 8.5.

• Journal of Microbiology and Biotechnology
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• v.24 no.1
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• pp.70-79
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• 2014

In an attempt to develop a variety of expression vector systems for Corynebacterium glutamicum, six types of promoters, including $P_{tac}$, $P_{sod}$, $P_{sod}$ with a conserved Shine-Dalgarno (SD) sequence from C. glutamicum, $P_{ilvC}$, $P_{ilvC}$ with a conserved SD-1 ($P_{ilvC-M1}$), and $P_{ilvC}$ with a conserved SD-2 ($P_{ilvC-M2}$), were cloned into a modified shuttle vector, pCXM48. According to analysis of promoter strength by quantitative reverse transcription PCR, $P_{sod}$ and $P_{sod-M}$ were superior to tac and ilvC promoters in terms of transcription activity in C. glutamicum. All of the promoters have promoter activities in Escherichia coli, and $P_{sod-M}$ displayed the highest level of transcriptional activity. The protein expression in constructed vectors was evaluated by measuring the fluorescence of green fluorescent protein (GFP) and SDS-PAGE. C. glutamicum harboring plasmids showed GFP fluorescence with an order of activity of $P_{ilvC}$ > $P_{ilvC-M1}$ > $P_{sod}$ > $P_{ilvC-M2}$ > $P_{sod-M}$, whereas all plasmids except pCSP30 with $P_{sod}$ displayed fluorescence activities in E. coli. Of them, the strongest level of GFP was observed in E. coli with $P_{sod-M}$, and this seems to be due to the introduction of the conserved SD sequence in the translational initiation region. These results demonstrate that the expression vectors work well in both C. glutamicum and E. coli for the expression of target proteins. In addition, the vector systems harboring various promoters with different strengths, conserved SD sequences, and multiple cloning sites will provide a comfortable method for cloning and gene expression, and consequently contribute to the metabolic engineering of C. glutamicum.

• Journal of the Korean Chemical Society
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• v.45 no.2
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• pp.162-176
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• 2001

This study was covered with the analysis of five kinds of the middle school science text books(chemistry part) based on the oth curriculum. Particularly, inquiry activities part was analyzed by the three dimension framework which consists of inquiry content dimension, inquiry process dimension and inquiry context dimension and the results are as follows;1. In the analysis of the contents in the middle school science textbooks(chemistry part), the average number of total pages was 197.6. The illustration and picture were contained 0.66 in number per a page, and the average number of further readings was 5.8.2. In the analysis of the inquiry content dimension of inquiry activities, the total number of themes in five kinds of textbooks was 222. And the number of imquiry activities in five kinds of textbooks was siverse : A textbook had 51, B texbook 49, C textbook 37 and E textbook 35.3. For the analysis of inquiry process dimension. it follows in the order of 'interpreing data and formulating generalizations (42.4%)','observation and measuring (38.1%)','seeing a problem and seeking ways to solve it (7.8%)' and 'building, testing and revising the theoretical model(11.7%)'.4. As for the analysis of the inquiry context dimension, the scientific context occupied 94.2%, the individual context 0.4%, the social context 2.7% and the technical context 2.7%. It shows that the proportion of STS(Science-Technology-Society) related contents in inquiry activities was only 5.8%.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.82-86
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• 2012

In For the past few years, query log data has been collected to find user's behavior in using the site. Many researches have studied on the usage of query logs to extract user's preference, recommend personalization, improve caching and pre-fetching of Web objects, build better adaptive user interfaces, and also to improve Web search for a search engine application. A query log contain data such as the client's IP address, time and date of request, the resources or page requested, status of request HTTP method used and the type of browser and operating system. A query log can offer valuable insight into web site usage. A proper compilation and interpretation of query log can provide a baseline of statistics that indicate the usage levels of website and can be used as tool to assist decision making in management activities. In this paper we want to discuss on the tasks performed of query logs in pre-processing of web usage mining. We will use query logs from an online newspaper company. The query logs will undergo pre-processing stage, in which the clickstream data is cleaned and partitioned into a set of user interactions which will represent the activities of each user during their visits to the site. The query logs will undergo essential task in pre-processing which are data cleaning and user identification.