• The Plant Pathology Journal
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• v.25 no.4
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• pp.429-432
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• 2009

An unreported disease of apricot was observed in orchards in Zhejiang province, China. Symptoms started as water soaked lesions on the fruit surface. Later, water-soaked areas developed and spread to the entire fruit, resulting in soft rot of the whole fruit. The causal organism isolated from symptomatic fruits was identified as Burkholderia cepacia based on its biochemical and physiological characteristics and confirmed by the cellular fatty acid composition and Biolog data as well as 16S rRNA gene sequence analysis. The bacterial isolates caused similar symptoms when inoculated onto fruits of apricot. In addition, European plum, Japanese plum, nectarine and kiwifruit were susceptible to the B. cepacia pathogen. However, the B. cepacia pathogen failed to cause any visible symptoms when it was inoculated onto 16 other fruits. This is the first report of a bacterial disease of apricot caused by B. cepacia in China.

• The Plant Pathology Journal
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• v.36 no.4
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• pp.346-354
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• 2020

Pectobacterium, which causes soft rot disease, is divided into 18 species based on the current classification. A total of 225 Pectobacterium strains were isolated from 10 main cultivation regions of potato (Solanum tuberosum), napa cabbage (Brassica rapa subsp. pekinensis), and radish (Raphanus sativus) in South Korea; 202 isolates (90%) were from potato, 18 from napa cabbage, and five from radish. Strains were identified using the Biolog test and phylogenetic analysis. The pathogenicity and swimming motility were tested at four different temperatures. Pectolytic activity and plant cell-wall degrading enzyme (PCWDE) activity were evaluated for six species (P. carotovorum subsp. carotovorum, Pcc; P. odoriferum, Pod; P. brasiliense, Pbr; P. versatile, Pve; P. polaris, Ppo; P. parmentieri, Ppa). Pod, Pcc, Pbr, and Pve were the most prevalent species. Although P. atrosepticum is a widespread pathogen in other countries, it was not found here. This is the first report of Ppo, Ppa, and Pve in South Korea. Pectobacterium species showed stronger activity at 28℃ and 32℃ than at 24℃, and showed weak activity at 37℃. Pectolytic activity decreased with increasing temperature. Activity of pectate lyase was not significantly affected by temperature. Activity of protease, cellulase, and polygalacturonase decreased with increasing temperature. The inability of isolated Pectobacterium to soften host tissues at 37℃ may be a consequence of decreased motility and PCWDE activity. These data suggest that future increases in temperature as a result of climate change may affect the population dynamics of Pectobacterium.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 1996.06a
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• pp.33-33
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• 1996

Interests in the field of rapid methods and automation in microbiology have been growing steadily on an international scale in recent years. International meetings concerned this problem have been held in elsewhere in the world countries since the past twenty years. But, unfortunately in the field of microbial examination in food hygiene, this problem have not yet been developed so much as in the field of clinical microbiology. Today, I would like to introduce you here present aspects of rapid and automation technologies, those which are manly carrying in milk and meats industries. My illustration will be given recent improved technologies using automatic apparatus and instruments along with process of microbial count procedure. Recent direct microbiological counting system (ChemeScan \ulcorner) as real time ultrasensitive analysis created by Cheminex Ltd., France is now most evolutional instrument to provide direct microbial counts, down to one cell, within 30 minutes. The results from these evaluations how a good correlation between the ChemScan system and the standard plate count method. This system will be successful application for not only in the field of pharmacology but also food microbiology. In addition, current identification of microbes by sophisticated instruments suitable for food microbiology, one of which Biology is manual system (BIOLOG\ulcorner), provides reference-level capability at a modes price. For the manual system, the color reactions in the microplate are read by eye and manually keyed into personal computer. Species identification appears on the computer screen within seconds, along with biotype patterns, a list of closely related species, and other useful statistics. In present this is useful application for microbial ecology and epidemiological survey. RiboPrinter system newly produced by DuPont is now focusing among microbiologists in the world, and is one of the biggest microbial characterization system using a DNA-based approach. The technology analyzer is bacterial culture for its genetic fingerprint or riboprint pattern. Finally Bio-cellTracer system for automatic measurement of fungal growth and Fukitori-Maseter, a Surface Hygiene Monitoring Kit by using swabe procedure in food processing environment are briefly illustrated in this presentation.

• The Plant Pathology Journal
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• v.39 no.1
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• pp.88-107
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• 2023

In the present investigation, bacterial isolates from infected apple trees causing apple canker during winter were studied in the northern Gyeongbuk Province, Korea. The pathogen was identified as Pseudomonas syringae pv. syringae (Pss) through various physiological and biochemical characterization assays such as BIOLOG, gas chromatography of fatty acid methyl esters, and 16S rRNA. Bioassays for the production of phytotoxins were positive for syringopeptin and syringomycin against Bacillus megaterium and Geotrichum candidum, respectively. The polymerase chain reaction (PCR) method enabled the detection of toxin-producing genes, syrB1, and sypB in Pss. The differentiation of strains was performed using LOPAT and GATTa tests. Pss further exhibited ice nucleation activity (INA) at a temperature of -0.7℃, indicating an INA⁺ bacterium. The ice-nucleating temperature was -4.7℃ for a non-treated control (sterilized distilled water), whereas it was -9.6℃ for an INA^- bacterium Escherichia coli TOP10. These methods detected pathogenic strains from apple orchards. Pss might exist in an apple tree during ice injury, and it secretes a toxin that makes leaves yellow and cause canker symptoms. Until now, Korea has not developed antibiotics targeting Pss. Therefore, it is necessary to develop effective disease control to combat Pss in apple orchards. Pathogenicity test on apple leaves and stems showed canker symptoms. The pathogenic bacterium was re-isolated from symptomatic plant tissue and confirmed as original isolates by 16S rRNA. Repetitive element sequence-based PCR and enterobacterial repetitive intergenic consensus PCR primers revealed different genetic profiles within P. syringae pathovars. High antibiotic susceptibility results showed the misreading of mRNA caused by streptomycin and oxytetracycline.

• The Plant Pathology Journal
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• v.25 no.1
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• pp.91-94
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• 2009

An unreported disease of garlic was observed in commercial fields in Jiangsu province, China. The symptoms started as water soaked lesions at the base of the leaves. Later, water-soaked areas developed on stems and spread to the internal tissues, followed by yellowing and necrosis along leaf edges and soft rot of the stems. The causal organism isolated from symptomatic plants was identified as Pseudomonas fluorescens based on its biochemical and physiological characteristics and confirmed by the cellular fatty acid composition and Biolog data as well as 168 rRNA gene sequence analysis. The bacterial isolates caused similar symptoms when inoculated onto garlic plants. In addition, leek and shallot were susceptible to the P. fluorescens pathogen. However, the P. fluorescens pathogen failed to cause any symptoms when it was inoculated onto 15 other plants. This is the first report of a bacterial disease of garlic caused by P. fluorescens in China.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.451-456
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• 2014

Organic amendment practices can influence diversity and activities of soil microorganisms. There is a need to investigate this impact compared with other types of materials. This study was carried out to evaluate the long term effects of chemical and organic fertilizer on soil microbial community in upland field. During the last 11 years green manure, rice straw compost, rapeseed cake, pig mature compost, NPK, and NPK + pig mature compost were treated in upland soil. Organic fertilizer treatment found with high bacterial colony forming units (CFUs) as compared to chemical and without fertilizer treatment. There was no significant difference in the actinomycetes and fungal population. The average well color development (AWCD) value was the highest in green manure and, the lowest in without fertilizer treatment. Analyses based on the denaturing gradient gel electrophoresis (DGGE) profile showed that rice straw compost and pig mature compost had a similar banding pattern while rapeseed cake, NPK, NPK + pig mature compost and without fertilizer treatment were clustered in another cluster and clearly distinguished from green manure treatment. Bacterial diversity can be highly increased by the application of organic fertilizer while chemical fertilizer had less impact. It can be concluded that green manure had a beneficial impact on soil microbial flora, while, the use of chemical fertilizer could affect the soil bacterial communities adversely.

• Journal of Environmental Science International
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• v.20 no.4
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• pp.457-463
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• 2011

This study was carried out to compare the toxicity of nano and micrometer particles with Cu and Zn on soil microbial community and metal uptake of buck wheat. In microcosm system, soil was incubated for 14 days after soil aliquots were artificially contaminated with 1,000 mg/kg Cu, Zn nano and micro particles, respectively. After then, buck wheat was planted in incubating soils and non incubating soils. After 14 days, we compared bioaccumulation of metal, and microbial carbon substrate utilization patterns between incubating soils and non-incubating soils. The enrichment factor (EF) values of incubating samples were greater than non-incubating soils. Dehydrogenase activity had been inhibited by Cu and Zn nanoparticles in non-incubating soil, as well as it had been inhibited by Zn micro particles in incubating soils. Results of biolog test, it was not significant different between nano particles and micro particles. It cannot be generalized that nanoparticles of metal are always more toxic to soil microbial activity and diversity than micrometer-sized particles and the toxicity needs to be assessed on a case-by-case basis.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.176-182
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• 2003

An alkaline fibrinolytic protease-producing bacteria was isolated front Korean traditional soy sauce and identified as Bacillus subtilis K7 from the results of analyses of its morphological and physiological properties, $API^{\circledR}$, and Biolog system. The enzyme was purified by 75% ammonium sulfate fractionation, QAE-Sephadex anion and SP-Sephadex cation exchange column chromatography and Sephadex G-100 gel filtration. The specific activity of the purified enByme was 233.9 unit/mg protein and the yield of enzyme was 3.8%. The homogeneity of the purified enzyme was confirmed by polyacrylamide gel electrophoresis. Molecular mass of the enzyme was estimated about 21,500 Da by SDS-polyacrylamide get electrophoresis and gel chromatography. The optimum temperature and pH for the enzyme activity were $40^{\circ}C$ and 9.0, respectively. The enzyme was stable in a pH range of 5.0 to 12.0, and 60% of its activity was lost on heat treatment at $50^{\circ}C$ for 20 min. The activity of the purified enzyme was inhibited by the presence of $Fe^{2+},\;Ag^{2+},\;Cu6{2+}$, iodoacetate, ethylene diamine tetraacetic acid (EDTA), and trans-1,2-diaminocycloheane-N,N,N',N'-tetraacetic acid (CDTA). The results indicates that the enzyme requires a metal ion for its enzymatic activity.

• The Plant Pathology Journal
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• v.37 no.2
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• pp.137-151
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• 2021

The present study describes the bacterial blight of walnut, caused by Xanthomonas arboricola pv. juglandis (Xaj) in the northern Gyeongbuk province, Korea. Disease symptoms that appear very similar to anthracnose symptoms were observed in walnut trees in June 2016. Pathogens were isolated from disease infected leaves, fruits, shoots, bud, flower bud of walnut, and cultured onto yeast dextrose carbonate agar plates. Isolated bacteria with bacterial blight symptoms were characterized for their nutrient utilization profiles using Biolog GN2 and Vitek 2. In addition, isolates were subjected to physiological, biochemical, and morphological characterizations. Furthermore, isolates were identified using 16S rDNA sequence analysis, and multi-locus sequence analysis using atpD, dnaK, efp, and rpoD. To confirm pathogenicity, leaves, fruits, and stems of 3-year-old walnut plants were inoculated with bacterial pathogen suspensions as a foliar spray. One week after inoculation, the gray spots on leaves and yellow halos around the spots were developed. Fruits and stems showed browning symptoms. The pathogen Xaj was re-isolated from all symptomatic tissues to fulfill Koch's postulates, while symptoms were not appeared on control plants. On the other hand, the symptoms were very similar to the symptoms of anthracnose caused by Colletotrichum gloeosporioides. When walnut plants were inoculated with combined pathogens of Xaj and C. gloeosporioides, disease symptoms were greater in comparison with when inoculated alone. Xaj population size was more in the month of April than March due to their dormancy in March, and sensitive to antibiotics such as oxytetracycline and streptomycin, while resistant to copper sulfate.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.108-113
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• 2003

Diesel oil-degrading bacterial strains were isolated from diesel oil contaminated soil and called HS series (HS1, HS2 and HS3). These strains were identified as Acinetobacter sp. (HS1) and Pseudomonas sp. (HS2 and HS3) based on Biolog test, cellular fatty acid composition, and 16S rDNA sequence analysis. These strains were coltivated in liquid minimal media containing 2% diesel oil, and diesel oil-degrading activity was measured. As result, all strains degraded over 70% of total diesel oil. But PAH (polycyclic aromatic hydrocarbon)- and pris- tane-degrading rate of these strain was below 20％ of total PAH and pristane. The HS 1 strain showed highest hydrophobicity and low emulsifying activity among the experimental strains and high diesel oil-degrading activity. From the above-mentioned result, microcosm experiment was performed with the HS1 strain. The HS1 strain showed a degrading activity of over 80% of total diesel oil in microcosm test. And microbial activity was correlated to diesel oil-degrading activity. Therefore, it is suggested that the HS1 strains could be effectively used for the bioremediation for diesel oil.