• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1350-1355
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• 2004

The sprA and sprB genes, encoding the chymotrypsin-like proteases Streptomyces griseus protease A (SGPA) and Streptomyces griseus protease B (SGPB), and the sprT gene that encodes Streptomyces griseus trypsin (SGT) were cloned from S. griseus and were overexpressed in various strains of S. griseus. When the sprT gene was introduced into S. griseus, trypsin activity increased 2-fold in the A-factor deficient mutant strain, S. griseus HH1, and increased 4-fold in the wild strain, S. grise us IFO 13350. However, there was no detectable increase of chymotrypsin activity in the transformants of S. griseus with either sprA or sprB, in contrast to the results obtained from S. lividans as a heterologous host. To solve the negative gene dosage effects in S. griseus, either the sprA or the sprB genes with their own ribosome binding sites were linked to the downstream of the entire sprT gene, and the coexpression efficiency was examined in S. lividans and S. griseus. The transformants of S. lividans with either pWHM3-TA (sprT+sprA) or pWHM3­TB (sprT+sprB) showed 3-fold increase of trypsin activity over that of the control, however, only the transformant of pWHM3-TB demonstrated 7-fold increase in chymotrypsin activity, indicating that the pWHM3-TB has a successful construction for the overexpression of chymotrypsin in Streptomyces. When the coexpression vectors were introduced into S. griseus IFO 13350, the trypsin level sharply increased by more than 4-fold, however, the chymotrypsin level did not increase. These results strongly suggest that the overexpression of the sprA and sprB genes is tightly regulated in S. griseus.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1125-1129
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• 2005

Cloning of a 6.6-kb BamHI digested chromosomal DNA from S. griseus IFO13350 revealed the presence of an additional gene encoding a novel trypsin-like enzyme, named SprU. The SprU protein shows a high homology ($79\%$ identity, $88\%$ similarity) with the SGT protease, which has been reported as a bacterial trypsin in the same strain. The amino acid sequence deduced from the nucleotide sequence of the sprU gene suggests that SprU is produced as a precursor consisting of an amino-terminal presequence (29 amino acid residues), prosequence (4 residues), and mature trypsin consisting of 222 amino acids with a molecular weight of 22.94 kDa and a calculated pI of 4.13. The serine, histidine, and aspartic acid residues composing the catalytic triad of typical serine proteases are also well conserved. When the trypsin activity of the SprU was spectrophotometrically measured by the enzymatic hydrolysis of the artificial chromogenic substrate, N-${alpha}$-benzoyl-DL-arginine-p-nitroanilide, the S. lividans transformant with pWHM3-U gave 3 times higher activity than that of control. When the same recombinant plasmid was introduced into S. griseus, however, the gene dosage effect was not so significant, as in the cases of other genes encoding serine proteases, such as sprA, sprB, and sprD. Although two trypsins, SprU and SGT, have a high degree of homology, the pI values, the gene dosage effect in S. griseus, and the gene arrangement adjacent to the two genes are very different, suggesting that the biochemical and biological function of the SprU might be quite different from that of the SGT.

• Journal of Welding and Joining
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• v.34 no.2
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• pp.54-58
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• 2016

SPR(Self-Piercing rivet) is mechanical element of joining sheet metal components without the need for pre-punched or pre-drilled holes. Newly designed SPR is developed for high joining strength and shearing strength than semi-tubular rivet. In this study, divided shank of self-piercing rivet were designed for joining DP440 and SILAFONT. Newly designed SPR was simulated by using FEM code DEFORM-3D. In simulations of SPR process, various shape of self-piercing rivet were considered for semi-tubular and newly designed SPR. In other to examine the joinability, joining load and lap-shear load of newly designed SPR were compared with semi-tubular by simulated results and experimental ones.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.147-154
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• 2009

This paper presents a grating~integrated SPR (Surface Plasmon Resonance) sensor chip for simple and inexpensive biomolecule detection. The grating-integrated SPR sensor chip has two sensing channels having a nano grating for SPR coupling. An external mirror is used for multi channel SPR sensing. The present sensor chip replaces bulky and expensive optical components, such as fiber-optic switches or special shaped prisms, resulting in a simple and inexpensive wavelength modulated multi-channel SPR sensing system. We fabricate a SPR sensor chip integrated with 835 nm-pitch gratings by a micromolding technique to reduce the fabrication cost. In the experimental characterization, the refractive index sensitivity of each sensing channel is measured as $321.8{\pm}8.1nm$/RI and $514.3{\pm}8.lnm$/RI, respectively. 0.5uM of the target biomolecule (streptavidin) was detected by a $1.13{\pm}0.16nm$ shift of the SPR dip in the 10%-biotinylated sample channel, while the SPR dip in the reference channel for environmental perturbation monitoring remained at the same position. From the experimental results, multi-channel biomolecule detection capability of the present grating-integrated SPR sensor chip has been verified. On the basis of the preliminary experiments, we successfully measured the binding reaction rate for the $2\;nM{\sim}200\;nM$ monoclonal-antibiotin, thus verifying biomolecule concentration detectability of the present SPR sensor chip. The binding reaction rates measured from the present SPR sensor chip agredd well with those from a commercialized SPR sensor.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.81-88
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• 2007

The sprC gene encodes Streptomyces griseus protease C (SGPC), a bacterial chymotrypsin-like serine protease. Because the published data on sprC was not complete, we cloned and analyzed a new DNA fragment spanning downstream to upstream of the sprC gene from S. griseus IFO13350. The cloned 2.3-kb DNA fragment was placed on a high-copy number plasmid and introduced into Streptomyces lividans TK24. Chymotrypsin activity of the transformant was 8.5 times higher than that of the control after 3 days of cultivation and stably maintained until 9 days of cultivation, which dearly indicated that the cloned 2.3-kb fragment contained the entire sprC gene with its own promoter. When the same construct was introduced in the S. griseus IFO13350 (wild strain) and its two mutant strains in the A-factor regulatory cascade, ${\Delta}adpA$ and HO1, the chymotrypsin activity increased fivefold only in the ${\Delta}adpA$ strain. Transcriptional analysis based on RT-PCR revealed that the sprC gene is normally transcribed in both strains; however, earlier transcription was observed in the wild strain compared with the ${\Delta}adpA$ strain. A gel mobility shift assay showed that the AdpA protein did not bind to the promoter region of sprC. All these data clearly indicate that the expression of sprC is not dependent on the AdpA protein, but is distinctly regulated from other chymotrypsin genes composing an AdpA regulon. Earlier morphological differentiation was observed in S. lividans TK24, and S. griseus IFO13350 and HO1, transformed with the expression vector. The transformant of S. griseus ${\Delta}adpA$ formed markedly larger colonies. Antisense repression of sprC resulted in severe decrease of chymotrypsin activity, down to one-third of the control, and delayed morphological differentiation. All these data suggest that SGPC is related to normal morphogenesis in S. griseus.

• Journal of Biosystems Engineering
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• v.28 no.2
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• pp.167-172
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• 2003

This study was performed to fabricate a batch-type SPR biosensing system using a thiolated E. coli antibody coupling, and to explore the feasibility of real-time detection of E. coii in a stagnant sample solution. In advance. “O” and “K” antigenic serotype E. coli antibodies were thiolated with sulfo-LC-SPDP and dithiothreitol, and immobilized by chemisorption in the gold surface of compact SPR sensors. When the SPR biosensor immobilized with E. coli antibody monitored a E. coli solution, it took 3 to 5 min to stabilize. The SPR biosensing system developed in this study was able to detect E. coli in the range above 10$^4$ CFU/mL at the 0.05 significant level. Also, the SPR biosensor had possibility to significantly detect E. coli in the range of 10$^2$ to 10$^4$ CFU/mL in E. coli solutions. Meanwhile, when the SPR biosensor immobilized with 5. coli antibody was cleaned with NaOH solutions, its ability to detect E. coli largely decreased due to wash-out of the immobilized antibody. In order to reuse the SPR sensor, it should be antibody-immobilized newly.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.5
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• pp.442-450
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• 2011

A measurement system using stereo pattern recognition (SPR) method was configured to measure the rotor blade deformations and motions. An SPR-based measurement system was prepared using six stereo cameras. Through a series of experiments to evaluate the system measurement uncertainty, it was verified that the SPR system had less than 0.2mm standard uncertainty. The combined standard uncertainties for the lead-lag, flapping, and pitching motions were estimated as 0.296mm, 0.209mm, and $0.238^{\circ}$, respectively. The SPR system was installed at a general small-scaled rotor test system at Korea Aerospace Research Institute. The blade motions and elastic deformation were successfully measured under the conditions with rotating speeds of 360rpm or 589rpm, and collective pitch angles of $0^{\circ}$, $4^{\circ}$, or $6^{\circ}$. The advantages of the SPR system was analyzed in comparison with the measurement system used in Higher Harmonic Control Aeroacoustic Rotor Test -II.

• Safety and Health at Work
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• v.14 no.3
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• pp.267-271
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• 2023

Background: The objective of this study is to identify the working conditions and health status of Vietnamese male migrant workers in Republic of Korea, in comparison to the Korean general population. Methods: We conducted our survey through the Migrant People Center, and we received completed questionnaires from 87 male Vietnamese migrant workers. The questionnaire employed was identical to those used in the Korean Working Conditions Survey and the 2020 Korea National Health and Nutrition Examination Survey. The collected data from the Vietnamese migrant workers was then compared with the Korean reference population using indirect age-standardization. Results: Vietnamese male workers demonstrated a higher prevalence of health problems including hearing problems (age-standardized prevalence ratio (aSPR) 13.22, 95% confidence interval [CI]: 8.07-20.4), skin problems (aSPR 13.49, 95% CI: 8.07-20.4), and low back pain (aSPR 8.40, 95% CI: 6.50-10.69). Elevated exposure to workplace hazards such as chemicals (aSPR 2.36, 95% CI: 1.51-3.51), organic solvents (aSPR 2.22, 95% CI: 1.44-3.28), handling of heavy objects (aSPR 1.67, 95% CI: 1.24-2.21), and high temperatures (aSPR 1.96, 95% CI: 1.46-2.57) was observed among them. Additionally, they faced a higher risk of no personal protective equipment (aSPR 2.53, 95% CI: 1.26-4.52) and a greater prevalence of unmet medical needs (aSPR 7.14, 95% CI: 4.74-10.32). Conclusion: Our findings highlight the elevated workplace hazards, health problems, and unmet medical needs among Vietnamese male workers compared to the Korean reference population. These findings underscores the urgency for enhanced scrutiny over working conditions and protective equipment provision, coupled with efforts to improve healthcare accessibility and worker education.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.547-552
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• 2008

The detection of carbamate (carbofuran, carbaryl, benfracarb, thiodicarb, and methomil) and organophosphate (diazinon, cadusafos, ethoprofos, parathion-methyl, and chlorpyrifos) pesticide residues with very low detection limits was carried out using surface plasmon resonance (SPR) based equipment. The capacity to develop a portable SPR biosensor for food safety was also investigated. The applied ligand for the immunoassays was polyclonal goat anti-rabbit immunoglobulin (IgG) peroxidase conjugate. Concentration tests using direct binding assays showed the possibility of quantitative analysis. For ligand fishing to find a proper antibody to respond to each pesticide, acetylcholinesterase (AChE), and glutathione-S-transferase (GST) were tested. The reproducibility and precision of SPR measurements were evaluated. With this approach, the limit of detection for pesticide residues was 1 ng/mL and analysis took less than 11 min. Thus, it was demonstrated that detecting multi-class pesticide residues using SPR and IgG antibodies provides enough sensitivity and speed for use in portable SPR biosensors.

• Journal of Welding and Joining
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• v.33 no.3
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• pp.75-80
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• 2015

Self-piercing riveting is an joining method of advanced high strength steels (AHSS) and other dissimilar materials. It has attracted considerable interest from the automotive industry. The SPR has become an interesting alternative joining technique for difficult to weld materials such as steels and aluminium alloys. In this paper, self-piercing rivet and anvil for SPR were designed for the joining conditions with AHSS and aluminium alloy. Various conditions of SPR were simulated for the design of rivets and anvils. The simulated results were in good agreement with experimental ones. As a result, over HV500 rivet is desirable to joint SPFC780 AHSS and aluminum alloy.