• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.674-683
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• 2012

A new strain, SD12, was isolated from tannery waste polluted soil and identified as Pseudomonas aeruginosa on the basis of phenotypic traits and by comparison of 16S rRNA sequences. This bacterium exhibited broad-spectrum antagonistic activity against phytopathogenic fungi. The strain produced phosphatases, cellulases, proteases, pectinases, and HCN and also retained its ability to produce hydroxamate-type siderophore. A bioactive metabolite was isolated from P. aeruginosa SD12 and was characterized as 1-hydroxyphenazine ((1-OH-PHZ) by nuclear magnetic resonance (NMR) spectral analysis. The strain was used as a biocontrol agent against root rot and wilt disease of pyrethrum caused by Rhizoctonia solani. The stain is also reported to increase the growth and biomass of Plantago ovata. The purified compound, 1-hydroxyphenazine, also showed broad-spectrum antagonistic activity towards a range of phytopathogenic fungi, which is the first report of its kind.

• 대한치과의사협회지
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• 제54권3호
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• pp.198-205
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• 2016

The purpose of this paper was to investigate the significance of splinted and non-splinted implant-supported restorations with an internal connection for multiple consecutively missing teeth. Upon examination of the effects of fixture-abutment connection, the distribution of occlusal load was favorable in splinted implant-prosthesis with an external connection, but effect of strain distribution was not significant in splinted implant-prosthesis with an internal connection. In splinted implant-prostheses for short implants, strain distribution was not affected by the method of retention. For cement-retained prostheses, the effect of strain distribution due to splinting was not significant. In clinical studies, non-splinted prostheses with an internal connection for multiple consecutively missing teeth showed high survival rate, mild marginal bone loss, and stable periodontal condition. However, failure to achieve optimal proximal contact between single-unit prostheses may lead to food impaction, and veneer fracture may be inevitable when the framework provides inadequate support in the proximal region. In conclusion, splinted implant-prosthesis is not an indication in all cases, and clinical consideration of its use should be based on the patient's oral condition, such as location and number of implants, formation of proximal contact, canine guidance, existence of parafunctional habit, and oral hygiene, when multiple consecutively missing teeth are replaced by internal connection type implant.

• Parasites, Hosts and Diseases
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• 제34권2호
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• pp.155-157
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• 1996

쥐와포자충(MCR주)을 장기간에 걸쳐 그 생명을 유지시키기 위하여 냉동 보존을 시도하였다. 그 오오시스트를 냉동보호제를 첨가하지 않고 증류수에 현탁시켜 $-20^{\circ}C$에서 24시간 예비냉각시킨 다음 $-70^{\circ}C$에 냉동보존하였다. 냉동 오오시스트를 $5^\circ}C$에서 해동시켜 마우스에 접종시킨 바 15개월간 냉동보존시켜토 사멸하지 않고 마우스에의 감염성이 유지되었다. 한편, 2.5% 중크롬산칼륨에 현탁시켜 6.5개월간 $5^{\circ}C$에 냉장한 오오시스트는 이미 사멸하여 감염성이 소실되었다.

• 소성∙가공
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• 제8권3호
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• pp.221-221
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• 1999

Warm deep drawability in a square cup drawing was investigated using a newly developed high-strength steel sheet with retained austenite that was transformed into martensite during formation. For this investigation, six different temperatures between room temperature and 250℃, and five different drawing ratios ranging from 2.2 to 2.6 were considered. The results showed that the maximum drawing force and the drawing depth were affected by the change in temperature, and a more stable thickness strain distribution was observed at elevated temperatures. However, blue shortness occurred at over 200℃. FEM analysis using the LS-DYNA code was used to compare the experimental results with the numerical results for the thickness strain distribution.

• Journal of Microbiology
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• 제35권3호
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• pp.234-238
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• 1997

Conditional lethal mutation nup49-1 of a nuclear pore complex component gene was constructed in Saccharomyces cerevisiae. This mutation deleted one third of the essential NUP49 gene at the carboxy-terminal, but retained 13 repeats of the highly conserved GLFG domain. The nup49-1 mutant strain was viable with a slow-growth phenotype, indicating that the C-terminal is dispensable at normal growth temperature. This strain exhibited both temperature-sensitivity at 37.deg.C and cold-sensitivity at 16.deg.C. Temperature shift experiments revealed that the arrest phenotype at 37.deg.C was random in the cell division cycle. The nup49-1 mutation was tested to be recessive and is expected to be useful for the functional analysis of nuclear pore complex proteins as well as for studies of nuclear transport systems.

• 한국미생물·생명공학회지
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• 제25권4호
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• pp.346-353
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• 1997

During the screening of cellulase producing microorganisms, a fungal strain C-4 was selected from etiolated leaves. Based on taxonomic studies, the fungus could be classified as a strain of Trichoderma sp. When the strain C-4 was cultured in Mandels' media at 28$circ$C for 6 days, the enzyme activities detected in broth were as follows: 8.2 U/ml (28.1 U/mg) of CMCase activity, 0.75 U/ml (2.58 U/mg) of Avicelase activity, 1.67 U/ ml (5.68 U/mg) of $eta$-glucosidase activity. The optimum pH for enzyme induction was 6.2. The crude enzyme retained 100% of its original CMCase activity at 50$circ$C for 1 hr (pH 5.0), and at 4$circ$C for 24 hrs (pH 5.0). There was no effect on the CMCase activity in the presence of 1 mM of CsCl, LiCl, MgCl$_{2}$, and FeCl$_{2}$, respectively. When the crude enzyme was treated with trypsin and chymotrypsin (2% W/w) for 10 minutes, the remaining CMCase activity was 70%, but there was no further loss of activity for 60 minutes treatment at 30$circ$C. The crude enzyme showed the synergism with rumen fluid for the hydrolysis of Avicel and CMC by 118% and 130%, respectively.

• Journal of Microbiology and Biotechnology
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• 제1권2호
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• pp.96-101
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• 1991

Phenotypic changes after plasmid curing experiment suggested that the bacteriocin production phenotype ($Bac^{+}$) might be linked to a chromosomal DNA and the mucin production phenotype ($Muc^{+}$) might be linked to a 62.5 kilobase (kb) plasmid (pMUC62) in Lactobacillus plantarum 27 isolated from meat starter culture. The non-mucoid ($Muc^{-}$) variants were missing pMUC62 but they produced bacteriocin as the wild strain ($Bac^{+}$). There was no difference in antibiotic resistance and sugar fermentation patterns between the wild strain ($Bac^{+}$ $Muc^{+}$) and the nonmucoid ($Bac^{+}$ $Muc^{-}$) variants. Antimicrobial spectrum of bacteriocin produced by both wild strain and $Muc^{-}$ variant of Lb. plantarum 27 included strains of Pediococcus acidilactici (A, M, H), Pediococcus sp. isolated from meat, Lactobacillus sp. isolated from meat, Lb. plantarum NCDO 955 and Staphylococcus aureus 485. Neither of the tested Gram negative bacteria were inhibited by bacteriocin. Antimicrobial activity of crude bacteriocin was retained after autoclaving, DNase or catalase treatment and exposure from pHs 4 to 9 but was lost after treating with several proteolytic enzymes and exposure at pH 10.

• 한국균학회지
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• 제17권3호
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• pp.145-148
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• 1989

Aspergillus niger K-25가 생산하는 내산성 ${\alpha}-amylase$를 정제하여 특성을 조사하였다. 분자량은 전기영동상에서 약 58,000달톤으로 나타났고, 최적 pH는 4였고, pH3에서 활성을 잃어 버리는 시판효소와 달리 본 효소는 91%의 활성을 유지했다. 최적 온도는 $40^{\circ}C$였으며, $60^{\circ}C$에서도 80%의 활성을 유지하여 열에 대한 안정성도 높은 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제23권6호
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• pp.872-877
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• 2013

In a previous study, we isolated and reported a second species of the Saccharophagus genus, Saccharophagus sp. strain Myt-1. In the present study, an alginate lyase gene (algMytC) from the genomic DNA of Myt-1 was cloned and characterized. The DNA sequence fragment obtained contained an open reading frame of 1,032 bp that encoded a protein of 343 amino acids with an estimated molecular mass of 37.6 kDa and a pI of 6.60. The deduced protein, AlgMytC, had the conserved amino acid sequences (RTELREM, QIH, YFKAGVYNQ) of the polysaccharide lyase family 7. A BLAST homology search indicated that AlgMytC shared an amino acid sequence identity of 95.9% with alg7A of S. degradans 2-40. The cloned and purified AlgMytC protein showed optimal activity at $40^{\circ}C$, and retained more than 90% of its total activity even after treatment at $25^{\circ}C$ for 24 h. AlgMytC was very alkaliphilic with an optimal pH of 9.0, and more than 90% of its activity was retained in the pH range 8.5-10.0. Moreover, AlgMytC was stable over a wide pH range. The activity of AlgMytC was also stable in the presence of various detergents.

• 한국산업융합학회 논문집
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• 제26권5호
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• pp.725-731
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• 2023

In this study, the harmless crack size was evaluated using carburized, quenched-tempered SCM822H steel. The possibility of detecting cracks that reduce the fatigue limit by non-destructive inspection was evaluated. The conclusions obtained are as follows. The retained austenite of surface was reduced by SP. About 35% and 65% of the retained austenite on the surface were transformed into strain-induced martensite, increasing the hardness by 79HV and 122HV over the as-received material. The maximum compressive residual stresses introduced on the surfaces were -695 MPa and -688 MPa, respectively. The fatigue limit increased by 1.48 times and 1.67 times, respectively, compared to the as-received material. The harmless crack size of SP specimen was determined differently depending on the shot ball size.