• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 1995.06b
• /
• pp.21-25
• /
• 1995

;Bacterial blight caused by Xanthomonas oryzae pv. Olyzae is one of the most important diseases of rice. Host resistance, which relies on single, dominant resistance genes, is the only reliable method to control the disease at present. Pathogenic variation of the bacteria has been shown to follow the deployment of resistance genes in commercial cultivars. Information on the factors and the mechanisms for genetic variation of this pathogen is limited. Further, we have no clear evidence of whether population variability is due to sexual recombination or to variation introduced by mutations or intragenic recombination in a clonally maintained population.(omitted)itted)

• Research in Plant Disease
• /
• v.10 no.4
• /
• pp.349-352
• /
• 2004

Antimicrobial activity of garlic extracts of four local cultivars (Namdo, Goheung, Danyang and garlic imported from China) against several plant pathogenic bacteria and fungi was investigated. The garlic extracts exhibited marked in vitro antimicrobial activities against the Gram-positive and -negative bacteria as well as fungal pathogens. Of the four cultivars, two cultivars (Namdo and garlic imported from China) showed relatively good antimicrobial activities. Gram-positive bacteria, Clavibater michiganensis was most sensitive, whereas Burkholderia cepacia was the strong resistant towards garlic extracts. Results from the planta bioassays under greenhouse conditions indicated that garlic extracts significantly reduced the cucumber powdery mildew disease showing control value 59.7-61.9% compared with the nontreated controls.

• Microbiology and Biotechnology Letters
• /
• v.35 no.3
• /
• pp.210-219
• /
• 2007

In this study was investigated the growth effect of native plant (Microlepia marginata(panzer Christ., Prunella vulgaris. aleutica Fernald, Perillafrutescens var. japonica Hara., Gleichenia japonica Spreng) extracts on various lactic acid bacterias, electron donating ability, total cell count and hydroxyl radical scavenging activity. The total cell count of Enterococcus faecium KCCM 12118, Lactobacillus rhamnosus KCCM 32826, Lactobacillus plantarum KCCM 11542, Pediococcus pentosaceus KCCM 40464 in the absence of native plant extracts (10%) at $37^{\circ}C$ after 48hr were $2.2{\times}10^9\;cfu/ml$, $2.1{\times}10^9\;cfu/ml$, $2.3{\times}10^9\;cfu/ml$, $2.2{\times}10^9\;cfu/ml$. On the other hand, the total cell count of E. faecium KCCM 12118, L. rhamnosus KCCM 32826, L. plantarum KCCM 11542, P. pentosaceus KCCM 40464 in the presence of native plant extracts (10%) at $37^{\circ}C$ after 48hr were $4.3{\times}10^9\;cfu/ml$, $4.3{\times}10^9\;cfu/ml$, $4.8{\times}10^9\;cfu/ml$, $3.9{\times}10^9\;cfu/ml$. The electron donating ability indicated to E. faecium KCCM 12118, L. rhamnosus KCCM 32826, L. plantarum KCCM 11542, P. pentosaceus KCCM 40464 added by 10% native plant extracts, respectively. when 10% native plant extracts were added lactic acid bacterias, the electron donating ability is the highest. Hydroxyl radical scavenging activity of E. faecium KCCM 12118, L. rhamnosus KCCM 32826, L. plantarum KCCM 11542, P. pentosaceus KCCM 40464 showed higher than that of control.

• Journal of Korean Society of Water and Wastewater
• /
• v.23 no.3
• /
• pp.339-344
• /
• 2009

The authors investigated the bacterial community attached to granular activated carbon(GAC) particles and the susceptibility of the community to chlorine disinfection. The study was carried out at the G Water Treatment Plant in Seoul, which was in full-scale operation. Bacteria attached to the surface of GAC increased gradually with treatment from $0.4{\times}106{\sim}8.5{\times}106 CFU/g$. TOC removal was under 1.0 mg/L due to increased bacterial community on the surface of GAC. It was found that TOC removal was closely related with physical and biological parameters such as pore volume and the number of attached bacteria. When the washed and the attached cells were disinfected with 1.0mg/L of chlorine for 1 hour, the washed cells with chlorination could be controlled, but the number of the attached cells increased gradually. The results suggest a possibility that the treatment and disinfection barriers can be penetrated and pathogenic bacteria may break into the drinking water supplying system.

• Research in Plant Disease
• /
• v.23 no.2
• /
• pp.89-98
• /
• 2017

Ralstonia solanacearum species complex (RSSC) causes bacterial wilt, and it is one of the most important soil-borne plant pathogenic bacteria. RSSC has a large host range of more than 50 botanical families, which represent more than 200 plant species, including tomato. It is difficult to control bacterial wilt due to following reasons: the bacterial wilt pathogen can grow inside the plant tissue, and it can also survive in soil for a long period; moreover, it has a wide host range and biological diversity. In most previous studies, scientists have focused on developing biological control agents, such as antagonistic microorganisms and botanical materials. However, biocontrol attempts are not successful. Plant-derived metabolites and extracts have been promising candidates to environmentally friendly control bacterial wilt diseases. Therefore, we review the plant extracts, essential oils, and secondary metabolites that show potent in vivo antibacterial activities (in potted plants or in field) against tomato bacterial wilt, which is caused by RSSC.

• Research in Plant Disease
• /
• v.12 no.1
• /
• pp.51-54
• /
• 2006

The effectiveness of four plant oils (garlic, ginger, cinnamon and lemongrass) against a range of plant pathogenic organisms was tested in vitro. Of the four oils, two oils (garlic and cinnamon) showed relatively good antimicrobial activities. Activity of garlic oil was shown against the plant pathogenic bacteria Agrobacterium tumefaciens, Ewinia carotovora, Ralstonia solanacearum, Xanthomonas campestris, and the fungi Phytophthora infestans, Fusarium oxysporum, Collectotricum sp., whereas Acidovorax avenae and Pythium sp. showed the resistance towards garlic oil. Results from the planta bioassays under greenhouse conditions indicated that garlic oil significantly reduced the cucumber powdery mildew (Sphaerotheca fusca) and tomato powdery mildew (Erysiphe cichoracearum) showing control value 70.0-74.6% and 71.2%, respectively.

• Korean Journal of Veterinary Service
• /
• v.44 no.1
• /
• pp.45-49
• /
• 2021

A 23-month-old Holstein cattle showed excess salivation and reluctance of walking and suddenly died after forced sudden movements. Grossly, numerous fibrous adhesions were present within cranial abdominal cavity including the reticulum and diaphragm and thoracic cavity involving lungs, pericardial sac, and heart. A perforation made by a 10 cm-long sharp-ended wire was detected in the reticulum. Histopathologically, fibrous suppurative epicarditis and myocardial necrosis were observed. Fibrosis with neovascularization were found in lungs, spleen, and liver. And granulomatous reticulitis was observed. For differential diagnosis, no pathogenic bacteria were detected through microbiological tests and PCR results were also negative for bovine susceptible pathogenic antigens. Based on the gross and histopathological examination, we diagnosed this case as chronic traumatic pericarditis. Cattle are inquisitive and prone to swallow various kinds of metallic foreign bodies since they do not use their lips. Therefore, avoiding ingestion of metallic objects in animal feed and animal areas by careful environmental management of farms is required and farmers should give the adequate minerals and vitamins into the feeds not to lick or shallow foreign bodies in case of mineral deficiency. For veterinary practitioners, physical examination, blood tests, and diagnostic imaging (X-ray and Ultrasonography) are required for an exact diagnosis. Furthermore, placing the magnets in rumen would be effective for prophylactic administrations.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.71.1-71
• /
• 2003

Most major plant pathogenic bacteria in Korea belong to Xanthomonas spp.. Xanthomonas oryzae pv. oryzae is a major pathogen in rice, X. campestris pv. vesicatoria in pepper, X. axonopodis pv. giycines in soybean, X. campestris pv. campestris in cabbage, and X. axonoposid pv. citri in tangerin. Host specificity of the bacterial pathogen depends on the avirulence gene in the pathogen and the corresponding resistance gene in host plants. Many avirulence genes in bacteiral pathogen located on the native plasmids. However, the presence of the native plasmids in Xanthomonas spp. was not investigated well. In order to study the host specificity, we isolated native plasmids from Xanthomonas spp. and compared those plasmids each other, The presence of the native plasmids and the characteristics of the plasmids depended on the bacterial strains. In the X. axonopodis pv. glycines, most strains carried native plasmids but some strains did not. Some strains carry about 60 kb native plasmids including 3 different aviurlence genes. We will discuss the characteristics of the native plasmids isolated from the Xanthomonas spp.

• Research in Plant Disease
• /
• v.6 no.1
• /
• pp.6-9
• /
• 2000

Nine samples of soft rotten roots and blighted leaves of Ficus spp. plants were collected from the vinyl-houses in Taejeon, Seongnam, Suweon and Yangjae in 1988 and pathogenic bactea were isolated from them Results of the studies on morphological, cultural, physiologucal and pathological characteristics indicated that the bacteria from Ficus retusa were Pseudomonas cichorii, from Ficus retusa \`Golden leaf\` and Ficus benjamina were P.viridiflava. These are the first description of bacteria which caused the diseases on Ficus spp. in Korea. We proposed to name the disease of Ficus retusa by P. cichorii as \"bacterial root rot of Ficus retusa\" and Ficus retusa(Golden leaf) and Ficus benjamina by P. viridiflava as \"bacterial leaf blight of Ficus retusa (Golden leaf)\", \"bacterial blight of Ficus benjamina\", respectively.

• The Plant Pathology Journal
• /
• v.16 no.5
• /
• pp.286-289
• /
• 2000

Mechanol extracts of three cold-tolerant eucalyptus trees-Eucalyptus darlympleana, E. gunnii and E. unigera were screened for antimicrobial activity against twenty two phyto-pathogenic fungi and six food-borne bacterial pathogens. E. unigera showed the antagonistic activity against all the tested pathogens. Among the tested fungal pathogens, Pythium species were highly sensitive to the leaf extracts. Especially, P. vanterpoolii, a causal agent of leaf blight in creeping bentgrass (Agrostis palustris), was completely inhibited by the extracts. The eucalyptus extracts were also effective in inhibiting the fungal growth of Botrytis cinerea and Phomopsis sp. isolated from the lesions of kiwifruit soft rot during post-harvest storage. Escherichia coli O-157 was less sensitive to the inhibition than the other bacterial pathogens tested. It was likely that Gram positive bacteria-Bacillus subtilis and Streptococcus mutans were more sensitive to the eucalyptus extracts than Gram negative bacteria-Escherichia coli, Salmonella enteritidis and Pseudomonas aeruginosa. Our findings suggest that the cold-tolerant eucalyptus species have antimicrobial properties that can serve the development of novel fungitoxic agents or food preservatives.