• Current Research on Agriculture and Life Sciences
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• v.31 no.1
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• pp.30-37
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• 2013

Bacillus subtilis and Bacillus amyloliquefaciens are closely related species that share a similar genomic background, and are both known to secrete large amounts of proteins directly into a medium. The extracellular proteomes of two strains of Bacillus subtilis and two strains of Bacillus amyloliquefaciens were compared by 2-D gel electrophoresis during the late exponential growth phase. The relative abundance of some minor protein spots varied among the four strains of Bacillus. Over 123 spots of extracellular proteins were visualized on the gel for B. subtilis CH 97, 68 spots for B. subtilis 3-5, 230 spots for B. amyloliquefaciens CH 51, and 60 spotsfor B. amyloliquefaciens 86-1. 2D gel electrophoresis images of the four Bacillus strains showed significantly different protein profiles. Consistent with the 2D gel electrophoretic analysis, most of the B. subtilis proteins differed from the proteases secreted by the B. amyloliquefaciensstrains. Among the proteins identified from B. subtilis, approximately 50% were cytoplasmic and 30% were canonically extracellular proteins. The secreted protein profiles for B. subtilis CH 97 and B. subtilis 3-5 were quite different, as were the profiles for B. amyloliquefaciens CH 51 and 86-1. The four proteomes also differed in the major protein composition. The B. subtilis CH 97 and B. amyloliquefaciens CH 51 proteomes both contained large amounts of secreted hydrolytic enzymes. Among the four strains, B. subtilis 3-5 secreted the least number of proteins. Therefore, even closely related bacteria in terms of genomic sequences can still have significant differences in their physiology and proteome layout.

• Korean Journal of Environmental Biology
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• v.41 no.2
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• pp.167-178
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• 2023

Large amounts of waste and wastewater from aquaculture have negatively impacted ecosystems. Among them, shrimp aquaculture wastewater contains large amounts of nitrogen contaminants derived from feed residues in an aerobic environment. This study isolated candidate strains from adult rockworms to treat shrimp aquaculture wastewater (SAW) in an aerobic environment. Among 87 strains isolated, 25 grew well at the same temperature as the shrimp aquaculture with excellent polymer degradation ability (>0.5 cm clear zone). Six isolates (strains AL1, AL4, AL5, AL6, LA10, and PR15) were finally selected after combining strains with excellent polymer degradation ability without antagonism. 16S rRNA sequencing analysis revealed that strains AL1, AL4, AL5, AL6, LA10, and PR15 were closely related to Bacillus paramycoides, Bacillus pumilus, Stenotrophomonas rhizophila, Bacillus paranthracis, Bacillus paranthracis, and Micrococcus luteus, respectively. When these six isolates were applied to SAW, they reached a maximum cell viability of 2.06×10⁵ CFU mL^-1. Their chemical oxygen demand (COD_Cr) and total nitrogen(TN) removal rates for 12h were 51.0% and 44.6%, respectively, when the COD_Cr/TN ratio was approximately 10.0. Considering these removal rates achieved in this study under batch conditions, these six isolates could be used for aerobic denitrification. Consequently, these six isolates from rockworms are good candidates that can be applied to the field of aquaculture wastewater treatment.

• International Journal of Industrial Entomology and Biomaterials
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• v.29 no.2
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• pp.185-192
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• 2014

Recombinant proteins can be generated quickly and easily in large amounts and at low-cost in silkworm larvae by using Bombyx mori nuclear polyhedrosis virus (BmNPV). We searched for high-permissive silkworm strains that have high production levels of heterologous proteins and are thus suitable for use as biofactories. In this study, we performed the analysis using a BmNPV vector expressing luciferase as a marker, and we confirmed protein expression by evaluating luciferase activity, determined by western blotting and luciferase ELISA, and confirmed transcription expression by semi- and quantitative real time PCR. For the selection of host silkworm strains, we first chose 52 domestic BmNPV sensitive strains and then identified 10 high-permissive and 5 low-permissive strains. In addition, to determine which hybrid of the high-permissive strains would show heterosis, nine strains derived through three-way crossing were tested for luciferase activity by western blotting, and luciferase ELISA. We found a correlation between luciferase activity and luciferase protein expression, but not transcription. There was no noticeable difference in protein expression levels between Jam313 as the high-permissive control strain and the three-way hybrid strains; however, the three-way cross strains showed lower luciferase activity compared with Jam313. In this study, luciferase protein production in the larvae of 52 domestic silkworm strains was elucidated using BmNPV.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.662-667
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• 2001

Some biological activities and isoflavone (daidzein, genisten) contents were investigated from chungkugjang (CK) fermented with black beans and Bacillus strains at 42$^{\circ}C$ for 72 hr. n antibacterial activity, black bean CK fermented with Bacillus megaterium SMY-212 was higher than that ferment4d with B. subtilis. In both CK the methanol extract fo large black bean CK was more effective than that of small black bean CK was more effective than that of small black bean. Hydrogen-donating activity of methanol extract of chungjugjang (MEC) prepared with large and small black soybean showed to be 76.4 and 75.5%, respectively. Hydrogen-donating activity of MEC prepared with B. subtilis and SMY-212 was slightly highter than that without both strains. MEC of large black bean was higher in nitrite-scavenging activity than that of small black bean, and black bean CKs fermented with B. subtilis and SMY-212 have no difference in nitrite-scavenging activity B. subtilis and SMY-212. MEC of black bean showed strong antioxidative activity against peroxidation of linoleic acid and $H_2O$$_2$-FeSO$_4$-induced peroxidation of rat liver homogenate. MEC of black bean with Bacillus strains was higher in antioxidative activities than that of black bean without Bacillus strains. Contents of isoflavone (daidzein, genistein) were gradually increased during fermentation of CK. The isoflavone content was slightly higher in large black bean CK than in small black bean CK.

• Smart Structures and Systems
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• v.8 no.5
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• pp.471-486
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• 2011

Various types of strain sensors have been developed and widely used in the field for monitoring the mechanical deformation of structures. However, conventional strain sensors are not suited for measuring large strains associated with impact damage and local crack propagation. In addition, strain sensors are resistive-type transducers, which mean that the sensors require an external electrical or power source. In this study, a gold nanoparticle (GNP)-based polymer composite is proposed for large strain sensing. Fabrication of the composites relies on a novel and simple in situ GNP reduction technique that is performed directly within the elastomeric poly(dimethyl siloxane) (PDMS) matrix. First, the reducing and stabilizing capacities of PDMS constituents and mixtures are evaluated via visual observation, ultraviolet-visible (UV-Vis) spectroscopy, and transmission electron microscopy. The large strain sensing capacity of the GNP-PDMS thin film is then validated by correlating changes in thin film optical properties (e.g., maximum UV-Vis light absorption) with applied tensile strains. Also, the composite's strain sensing performance (e.g., sensitivity and sensing range) is also characterized with respect to gold chloride concentrations within the PDMS mixture.

• Journal of the Korean GEO-environmental Society
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• v.6 no.3
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• pp.5-15
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• 2005

A large diameter sampler that can take undisturbed samples from soft ground was developed by KICT. In order to compare the quality of samples taken by the sampler with those of the traditional piston sampler, a series of laboratory tests were performed. Samples were taken at different sites such as Incheon, Gimhae, Yangsan and Busan. The results showed that the values of unconfined compression strength, secant modulus, pre-consolidation pressure, undrained shear strength, and shear modulus exhibited higher in samples taken by the large scale sampler. Strains at shear failure and volumetric strains were low for the new sampler. It was proved from the comparison that better quality samples could be obtained by the KICT sampler.

• ALGAE
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• v.33 no.1
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• pp.49-54
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• 2018

Red algal mitochondrial genomes (mtDNAs) can provide useful information on species identification. mtDNAs of Pyropia / Porphyra (Bangiales, Rhodophyta) have shown diverse variation in their size and gene structure. In particular, the introns and intronic open reading frames found in the ribosomal RNA large subunit gene (rnl) and cytochrome c oxidase subunit 1 gene (cox1) significantly vary the mitochondrial genome size in Pyropia / Porphyra species. In this study, we examined the exon / intron structure of rnl and cox1 genes of Pyropia yezoensis at the intraspecific level. The combined data of rnl and cox1 genes exhibited 12 genotypes for 40 P. yezoensis strains, based on the existence of introns. These genotypes were more effective to identify P. yezoensis strains in comparison to the traditional DNA barcode cox1 marker (5 haplotypes). Therefore, the variation in gene structure of rnl and cox1 can be a novel molecular marker to discriminate the strains of Pyropia species.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.252-256
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• 2000

The 16S-23S rRNA intergenic spacer regions (ISRs) were sequenced and analyzed to design specific primer for identification of Pectobacterium chrysanthemi. Two types ISRs, large and small ISRs, were identified from three strains (ATCC 11663, KACC 10163 and KACC 10165) of P. chrysanthemi and Pectobacterium carotovorum subsp. carotovorum ATCC 15713.Large ISRs contained transfer RNA-Ile(tRNA$^{Ile}$)and tRNA$^{Ala}$, and small ISRs contained tRNA$^{Glu}$. Size of the small ISRs of P. chrysanthemi ranged on 354-356 bp, while it was 451 bp in small ISR of P. carotovorum subsp. carotovorum ATCC 15713. From hypervariable region of small ISRs, species-specific primer for P. chrysanthemi with 20 bp length (CHPG) was designed from hypervariable region of small ISRs, which was used as forward promer to detect P. chrysanthemi strains with R23-1R produced PCR product of about 260bp size (CHSF) only from P. chrysanthemi strains, not from other Pectobacterium spp. and Erwinia spp. Direct PCR from bacterial cell without extracting DNA successfully amplified a specific fragment, CHSF, from P. chrysanthemi ATCC 11663. The limit of PCR detection was 1${\pm}10^2$ cfu/ml.

• The Korean Journal of Mycology
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• v.48 no.1
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• pp.55-61
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• 2020

In this study, we isolated endophytic fungal strains from the rhizoid and the leaf of Mnium heterophyllum and Hypnum plumaeforme, respectively. The isolated strains were identified based on morphological characters and molecular analysis of the internal transcribed spacer, large subunit rDNA, β-tubulin, and RNA polymerase II subunit regions. From the results, we confirmed two endophytic fungal species, Cercophora thailandica, and Biscogniauxia petrensis, which to the best of our knowledge, have not yet been reported in Korea. We further describe the morphological characteristics and the results of the molecular analyses of these isolated fungal strains.

• Journal of Microbiology
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• v.34 no.4
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• pp.327-333
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• 1996

Yeast, like many other microbes, encounters large variations in ambient pH in their natural environments. Microorganisms capable of growing over a wide pH range require a versatile, efficient pH homeostatic mechanism protecting intracellular processes against extremes of pH. In several organisms, fusions to the bacterial lacZ gene have been extremely useful for the identification of genes expressed at different time during the life cycle or under different growth conditions. In this study, using the lacZ gene screening system, we surveyed a large number of yeast strains with lacZ insertion to identify genes regulated by pH. A yeast genomic library was constructed and inserted with lacZ by a shuttle mutagenesis procedure. The yeast transformants were individually picked up with a toothpick, replica-plated, and grown in alkaline pH medium. Among the 35,000 colonies screened, 10 candidate strains were identified initially by the $\beta$-gal assay. We finally confirmed two yeast strains carrying the genes whose expression are strictly dependent on pH of growth medium. One of the fusions showing a 10-fold induction in expression level in response to alkali pH was selected and further characterized. The pH-regulated gene was cloned by inverse PCR and a partial sequence of the gene was determined. Identification and characterization of the gene is currently under investigation.