• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.574-582
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• 1992

Exo-xylanase encoded by the xylA gene of Bacillus stearothermoPhillus was produced from Escherichia coli ]M109 carrying a recombinant plasmid pMGL Synthesis of the enzyme was observed to be cell-associated, and about 94% of the enzyme synthesized was located in the cytoplasmic region. The maximum production was attained when the E. coli strain was grown at $37^{\circ}C$ for 8 hours on the medium containing 0.5% fructose, 1.0% tryptone, 1.0% sodium chloride, and 0.5% yeast extract. The exo-xylanase was purified to homogeneity using a combination of salting out with ammonium sulfate, DEAE-Sepharose CL-6B ion exchange chromatography, Sephadex G-IOO gel filtration, and Sephadex G-150 gel filtration. The' purified enzyme was most active at pH 6.0 and $45^{\circ}C$. $Ca^{2+}$ and $Co^{2+}$ activated the exo-xylanase activity by about 20% while $Ag^{2+}$, $Fe^{2+}$, $Mg^{2+}$ and $Zn^{2+}$ inhibited the enzyme activity by up to 60%. The $K_m$, value on p-nitrophenyl-$\beta$-D-xylanopyranoside was 2.75 mM. The enzyme had a pI value of 4.7. The estimated molecular weight of the native protein was 200,000 daL SDS-polyacrylamide gel electrophoresis analysis suggested that the native enzyme was a trimer composed of three identical 66,000 da!. polypeptides. The purified enzyme efficiently converted all the xylo-oligosaccharides tested to xylose. It was also confirmed that the enzyme split xylans in an exo-manner even though the degree of hydrolysis was fairly low. The xylanolytic enzyme was, therefore, classified to be one of the few bacterial exo-xylanases lacking transferase activity.

• Journal of fish pathology
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• v.22 no.1
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• pp.53-65
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• 2009

Tenacibaculum maritimum (formerly Flexibacter maritimus) is the aetiological agent of an ulcerative and necrotic disease commonly called tenacibaculosis in marine fish. Tenacibaculosis is an economically important disease in a great variety species in Jeju Island cultured fish and leading to this pathogen initially affected by skin, mouth, fins, tail causing severe necrotic and ulcerative lesions on the body surface. In the present study, A-7 strain was isolated from Paralichthys olivaceus showing symptoms of tenacibaculosis and identified as T. maritimum by morphological, biochemical and molecular biological analysis. T. maritimum A-7 is experimentally infected through immersion route in Paralichthys olivaceus which the disease outbreaks in land-based fish tanks of Jeju Island. Up to data a number of treatments proposed for the tenacibaculosis outbreaks are based on the immersion administration of drugs in tank. Oxytetracycline is the most widely used disinfectants in fish farms. However, most of fish farms manager and consumers have expressed concern as bioaccumulation in tissue and its environmental. In addition, this antimicrobial compounds is expensive in fish farmers. The overcome of this problem is desired the application of natural plant derived products. To obtain as 70% EtOH extract antimicrobial compounds against tenacibaculosis from 35 species of Jeju Island native plants were screened for antimicrobial activity against T. maritimum. In the present study were identified most of the plant extracts were better antimicrobial activity against T. maritimum.

• Journal of Life Science
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• v.23 no.1
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• pp.95-101
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• 2013

In this study, plant samples of five species were collected from the Dokdo islands in South Korea. Plant samples such as Asparagus schoberioides, Corydalis platycarpa, Festuca rubra, Sedum oryzifolium, and Setaria viridis were collected from the Dongdo and Seodo. Endophytic fungal strains were isolated from the roots of five plants from the Dokdo islands. Thirty-three fungal strains were isolated from these native plants. All the endophytic fungi were analyzed by internal transcribed spacer (ITS) sequencing (ITS containing ITS1, 5.8s, and the ITS2 region). Waito-c rice seedlings were treated with fungal culture filtrates to test their plant growth-promoting activity. A bioassay of the D-So-1-1 fungal strain isolated from S. oryzifolium confirmed that it has the highest plant growth-promoting activity. All the endophytic fungi belong to four orders: Eurotiales (86%), Capnodiales (3%), Hypocreales (4%), and Incertae sedis (7%). The endophytic fungi were classified as Ascomycota, which contained Aspergillus (12%), Cladosporium (3%), Eurotium (3%), Fusarium (18%), Microsphaeropsis (6%), and Penicillium (58%) at the genus level.

• Korean journal of applied entomology
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• v.53 no.2
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• pp.149-156
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• 2014

The resistance levels of the green peach aphid, Myzus persicae (Sulzer), against 10 insecticides was checked and selected the applicable insecticide resistance markers. We conducted our study in 5 cabbage cultivation regions (Pyeongchang, Hongcheon, Bongwha, Muju, and Jeju) of Korea, over 3 successive years (2009-2011). We selected a multi-resistant (MR) strain from among the 5 field-collected populations. We analyzed esterase over-expression and mutation(s) in the target sites, by using native isoelectric focusing (IEF) and quantitative sequencing (QS). We detected esterase over-expression and StoF mutation in the acetylcholinesterase 1 gene (ace1) in all of the field-collected populations, including the MR strain. We did not detect the LtoF mutation, which is a well-known knockdown resistance (kdr) mutation in the para-type sodium channel gene (para), in the MR strain; however, the value of the MR strain for bifenthrin was 3,461-fold higher than that of the susceptible strain. Our results indicate that insecticide resistance is more effectively evaluated using molecular markers than by conducting a bioassay. The molecular markers StoF in ace1 and MtoL in para can easily be applied in diagnostic methods such as QS or PCR amplification of specific alleles (PASA). These methods may be extended to management of M. persicae resistance in the field.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.895-902
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• 2014

Bacterial cellulose (BC) has played important role as new functional material for food industry and industrial products based on its unique properties. The interest in BC from static cultures has increased steadily in recent years because of its potential for use in medicine and cosmetics. In this study, we investigated culture condition for BC production by Acetobacter sp. F15 in static culture. The strain F15, which was isolated from decayed fruit, was selected on the basis of BC thickness. The optimal medium compositions for BC production were glucose 7%, soytone 12%, $K_2HPO_4$ 0.2%, $NaH_2PO_4{\cdot}_2H_2O$ 0.2%, lactic acid 0.05% and ethanol 0.3%, respectively. The strain F15 was able to produce BC at $26^{\circ}C-36^{\circ}C$ with a maximum at $32^{\circ}C$. BC production occurred at pH 4.5-8 with a maximum at pH 6.5. Under these conditions, a maximum BC thickness of 12.15 mm was achieved after 9 days of cultivation; this value was about 2.3-fold higher than the thickness in basic medium. Scanning electron micrographs showed that BC from the optimal medium was more compact than plant cellulose and was reticulated structure consisting of ultrafine cellulose fibrils. BC from the optimal medium was found to be of cellulose type I, the same as typical native cellulose.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.35-47
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• 2019

The mycelial growth of P. coccineus strain was good in PDA and YMA, but mycelial growth was low in MEA. Light irradiation during the incubation period affected the pigment formation and density of mycelia. Mushroom of P. coccineus strain was able to produce fruiting bodies in both bottle and bag cultivation, and oak sawdust was found to be the most suitable substrate for spawn culture and cultivation. In artificial cultivation using sawdust medium, fruiting body was grown to the extent that visual observation was possible from the 15th day, and it formed about 5 days fast in the treatment group with low relative humidity. From 40 to 45 days of mushroom development, mature fruiting bodies could be harvested, and the lower relative humidity of the growing room favored mushroom development and growth. Antioxidant activity of fruiting bodies harvested from artificial cultivation showed that ABTS radical scavenging activity of bottle-cultivated and wild fruit bodies were shown at 505㎍/㎖ and 515㎍/㎖, respectively. However, fruiting bodies harvested in bag cultivation were high at 910㎍/㎖. As a result of DPPH radical scavenging activity, all extracts were found to be inactive, exhibiting IC₅₀ value of more than 2,000㎍/㎖ concentration. The ethyl acetate extract of mushrooms obtained from bottle cultivation showed the highest activity with 1,550㎍/㎖ IC₅₀ value. Methanol extract of wild fruit bodies had the highest ABTS radical scavenging activity at the same concentration (10mg/㎖).

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.636-643
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• 2001

Bacillus sp. AIR-5, a strain from soil, produced an extracellular maltopentaose-forming amylase from amylose and soluble starch. This bacterium produced 8.9 g/l of maltopentaose from 40 g/l of soluble starch in a batch fermentation and the maltopentaose made up 90 % of the maltooligosaccharides produced (from maltose to maltoheptaose). The culture supernatant was concentrated using a 30 K molecular weight cut-off membrane and purified by DEAE-Cellulose and Sephadex G-150 column chromatographies. The purified protein showed one band on a native-PAGE and its molecular mass was estimated as 250 kDa. The 250-kDa protein was composed of tetramers of a 63-kDa protein. the isoelectric point of the purified protein was pH 6.9, and the optimum temperature for the enzyme activity was $45^{\circ}C$. The enzyme was quickly inactivated above $55^{\circ}C$, and showed a maximum activity at pH 8.5 and over 90% stability between a pH of 6 to 10. The putative N-terminal amino acid sequence of AIR-5 amylase, ATINNGTLMQYFEWYVPNDG, showed a 96% sequence similarity with that of BLA, a general liquefying amylase.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.85-92
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• 2002

A new isolate of Cucumber mosaic virus (CMV), identified as Li-CMV was isolated from a diseased Korean native lily (Lithium tsingtauense Gilg). Biological and serological properties of Li-CMV were characterized, and reverse transcription-polymerase chain reaction (RT-PCR) analysis, restriction enzyme profiling of RT-PCR products, and nucleotide sequence analysis of RNA3 of the virus were performed in this study. Remarkable differences in symptoms between Li-CMV and ordinary CMV strains were found in tobacco plants and Datura stramonium. Li-CMV-infected tobacco plants (cv. Xanthi-nc and cv. Samsun) induced chlorotic ringspots on uninoculated upper leaves, and the symptom expression was delayed or faint whereas, ordinary CMV strains induced green mosaic symptoms on the plant. Systemic infections were observed on Nicotiana benthamiana with severe mosaic symptom. Restriction mapping analysis of RT-PCR products using MspI showed that Li-CMV belonged to CMV subgroup I. A full-length CDNA copy of RNA3 for the virus was amplified by RT-PCR, cloned, and its complete nucleotide sequence was determined. The RNA3 of Li-CMV was 2, 232 nucleotides long, and consisted of two open reading frames of 843 and 657 bases encoding 3a protein (movement protein) and coat protein, respectively. Results of this study indicate that Li-CMV is a novel strain and belongs to subgroup I of CMV in the genus Cucumovirus.

• Journal of the Korean Society of Tobacco Science
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• v.1 no.1
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• pp.63-70
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• 1979

In order to improve the quality of greenish tobacco leaves, fermentation experiments by microbial treatment and periodical variations of fermentation temperature were performed. More than twenty strains were isolated from Hyangcho ( Sun cured Korean native leaves ) and Perique tobacco leaves. Among them, five strains which showed good growth in Nicotine Broth medium were selected. Identification experiments of these strains as well as checking the effects of fermentation by these treatment on the quality and aging rate of greenish tobacco leaves were carried out. The results were like following ; 1. Selected strains were identified as pseudomona.f for H-82, for P-4 and Bacillus for H-81. p- 4 and P-7. 2. Among the five strains, strain H- 82 showed the best effect on the forced aging and the quality of greenish tobacco leaves, The rate of oxygen uptaking, pH and nicotine contents were decreased. However, total volatile acids and petroleum ether extracts were increased. 3. After fermentation, taste from greenish tobacco leaf were removed and smoking characteristics were improved. Color was also changed from greenish yellow to dark brown.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1343-1349
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• 2004

A native strain of Pasteurella multocida was isolated from pigs suffering from severe atrophic rhinitis at domestic farms in Gyeonggi Province, Korea, and was identified as capsular serogroup 'D' and somatic serotype '4' by disc diffusion decapsulation and gel diffusion precipitation tests, respectively. The P. multocida (D:4) induced atrophic rhinitis in healthy pigs by the secondary infection. The gene for outer membrane protein H (ompH) of P. multocida (D:4) was cloned in Escherichia coli DH5$\alpha$ by PCR. The open reading frame of the ompH was composed of 1,023 bp, possibly encoding a protein with 341 amino acid residues containing a signal peptide of 20 amino acids at N-terminus, and the gene product with molecular mass of ca. 38 kDa was identified by SDS-PAGE. Hydropathy profiles indicated that there are two variable domains in the OmpH. To express the ompH in E. coli, the gene was manipulated in various ways. Expression of the truncated as well as full-length forms of the recombinant OmpH was fatal to the host E. coli BL21 (DE3). However, the truncated OmpH fused with GST was consecutively expressed in E. coli DH5$\alpha$. A large quantity of the fused polypeptide was purified through GST-affinity chromatography.