• Plant Disease and Agriculture
• /
• v.5 no.1
• /
• pp.1-7
• /
• 1999

The grain rot of caused by Bukholderia glumae was fist reported in japan in 1955 and then reported in other countries as well as in Korea in 1986. The pathogen causes both seedling and grain rot of rice but it cannot attack any other parts of adult rice plant. Bacterial colonies grow slowly, and are circular and greyish white. The causal bacterium is Gram-negative and rod shape with 1-3 polar flagella, and produce a diffusible yellow-greenish nonfluorescent pigment on King's medium B. Biochemical characteristics such as negative in arginine dehydrolase, oxidase reaction and nitrate reduction and positive in lecithinase, and the utilization of L-arginine and inositol are useful in differentiation of this from other nonfluorescent bacteria pathogenic to rice. This pathogenic bacterium had belonged to the genus of Pseudomonas but recently was transferred to the new genus Burkholderia on the basis of physiological characteristics and DNA-DNA hybridization data. However, other characteristics such as colony heterogenicity or colonial variation after subcultures, phytotoxin, secreting antibiotics, and relationship between yellow greenish pigment production and pathogenicity need to be clarified more. To develop an effective control strategy for this disease, understanding of detailed life cycle of the disease and critical environmental factors affecting disease development is prerequisite. Although 5,435 ha of rice paddy in Korea was infested during 1998, there is no exact estimation of yield losses and distribution of the pathogen. The review will focus on recent progress on the understanding of the bacteriological and ecological characteristics of the causal bacterium and control means of the disease.

• Food Science of Animal Resources
• /
• v.31 no.4
• /
• pp.513-520
• /
• 2011

In order to develop a new starter culture for fermented milk, Lactobacillus fermentum LC272 was isolated from raw milk and its physiological characteristics were investigated. The vitamin $K_2$ concentration of L. fermentum LC272 was $184.94{\mu}g/L$ in Rogosa medium and $63.93{\mu}g/L$ in the reconstituted skim milk. The optimum growth temperature for L. fermentum LC272 was determined to be $40^{\circ}C$ and it took 24 h for the pH to reach 5.2 under this condition. L. fermentum LC272 was more sensitive to rifampicin relative of the other 15 different antibiotics tested, and showed most resistance to streptomycin. L. fermentum LC272 showed higher activities to leucine arylamidase and acid phosphatase. It was comparatively tolerant to bile juice and acid and displayed high resistance against Salmonella Typhimurium and Staphylococcus aureus with rates of 82.9 and 86.3% respectively. These results demonstrated that L. fermentum LC272 could be an excellent starter culture for fermented milk with high levels of vitamin $K_2$ production.

• Journal of the Korean Chemical Society
• /
• v.33 no.6
• /
• pp.644-650
• /
• 1989

Syntheses of phthalide sulfone 2 and naphthalenone 6 followed by new ring annelation methodology of Michael addition using the sulfone anion developed by Hauser-Rhee, furnished linear tetracyclic ring system compound 11. The double bond existing in A-ring of 11 was used to convert to carbomethoxy compound 16, possessing one carbon atom more via Arndt-Eistert synthesis and Wolff rearrangement. Cyclization and hydroxylation of 16 completed the construction of (${\pm}$)-7-Deoxyaklavinone (18).

• Journal of Animal Environmental Science
• /
• v.19 no.2
• /
• pp.183-190
• /
• 2013

Establishment of a new concept of environmental friendly livestock manure management is required based on the facts. But now liquid fertilizer quality in korea shows a large difference among regions and the regulations are uncertain. Focusing on precedent study on main level-grading factors of liquid fertilizer quality certification, the study collected laws and standards related to liquid fertilizer of livestock manure at home and abroad and produced evaluation standards. Liquid fertilizer was divided into four factors (fertilizing value, harmfulness, stability and uniformity). According to each item, scores were awarded based on 16 details: fertilizing value (Nitrogen concentration, the whole concentration of Nitrogen, Phosphoric acid and Kalium), harmfulness (heavy metals, pathogenic microorganism and antibiotics), stability (maturity degree and odour), uniformity (EC, BOD, SS, moisture content and salt). The grade of liquid fertilizer, A (42~48), B (34~41), C (26~33) were rated using total scores.

• The Journal of the Korean Society for Microbiology
• /
• v.21 no.2
• /
• pp.191-204
• /
• 1986

Leptospira isolated from the patients with so called epidemic pulmonary hemorrhagic fever were comparatively studied with standard strains obtained from ATCC. The specific aim of this study was to clarify the morphologic heterogeneity of the isolates, i. e., coexistence of spiral forms in both handness, right and left, rod and spherical forms in their population by comparing them with those of the ATCC strains. No differences between our strains and ATCC strains were noticed in their growth characteristics, responses to the culture media, temperature, antibiotics and antifungal agents. Furthermore, the morphologic heterogeneity had been repeatedly observed even in cultures of standard ATCC strains, which had been noticed in the cultures of bacteria isolated in this laboratory. The serologic analysis of our isolates demonstrated that the bacteria reacted with L. icterohaemorrhagiae and L. australis regardless their differences in time of isolation(1984, 1985). Thus, it was concluded that the spiral bacteria isolated in this laboratory are Leptospira of a new serovar which still remained to be determined. And the previous reports on the morphology of the Leptospira, which described that the Leprospira population has only spiral forms with right. handed coils might be reconsidered.

• Korean Journal of Veterinary Research
• /
• v.49 no.2
• /
• pp.113-119
• /
• 2009

Atrophic rhinitis (AR) is the one of important respiratory diseases and causes severe economic losses in pig industry. Severe attempts have been made to reduce the economic losses by preventing the disease. One of the methods is the spraying of antibiotics into nasal cavity of piglets. Recently, the efficacy of the spraying with kanamycin and gentamicin was reduced in the Korean swine industry. Therefore, the preventive methods have been required to be changed based on the antimicrobial susceptibility profiles of causative agents of swine AR. Based on the current situations of this disease, Bordetella (B.) bronchiseptica and Pasteurella (P.) multocida 4D were isolated from pigs with clinical signs of AR. The isolation rates of B. bronchiseptica and P. multocida 4D were 58.5% and 32.9%, respectively. In the antimicrobial susceptibility test, the bacteria were resistant to kanamycin and gentamicin which have been used as the spraying agents, but they were susceptible to amikacin. A new spraying agent was developed using amikacin using ${\beta}$-glucan and yakbaltag as supplementary agents. Field efficacy of the agent was carried out with different schedule. The results from this study suggested that the newly developed spraying agents might be helpful to prevent AR in swine.

• Food Science of Animal Resources
• /
• v.30 no.6
• /
• pp.957-965
• /
• 2010

To develop a new starter culture for fermented milk, Streptococcus macedonicus LC743 was isolated from raw milk and its physiological characteristics were investigated. S. macedonicus LC743 showed good immunomodulating activity compared to the index LAB starters tested. The optimum growth temperature of S. macedonicus LC743 was $40^{\circ}C$, and it took 18 h to reach pH 4.34 under these conditions. S. macedonicus LC743 showed higher sensitivity to novobiocin in a comparison of 15 different antibiotics and showed the highest resistance to gentamycin. It also showed higher activities of leucine arylamidase and acid phosphatase. Moreover, it was comparatively tolerant to bile juice and acid and displayed high resistance to Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus with rates of 80.0%, 68.42%, and 81.54% respectively. These results demonstrate that S. macedonicus LC743 could be an excellent starter culture for fermented milk with a high level of immunomodulating activity.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.2
• /
• pp.346-353
• /
• 2005

A 50-kb chromosome DNA region was isolated from Streptomyces kanamyceticus by screening the fosmid genomic library, using the 16S rRNA methylase gene (kmr) as a probe. Sequence analysis of this region revealed 42 putative open reading frames (ORFs), which included biosynthetic genes such as genes responsible for 2-deoxystreptamine (2­DOS) biosynthesis as well as genes for resistance and regulatory function. Also, the kanamycin acetyltransferase gene (kac) was characterized by in vitro enzyme assay, which conferred E. coli BL21 (DE3) with 10, 50, and 80-times higher resistance to kanamycin A, tobramycin, and amikacin, respectively, than the control strain had, thus strongly indicating that the isolated gene cluster is very likely involved in kanamycin biosynthesis. This work provides a solid basis for further elucidation of the kanamycin biosynthesis pathway as well as the productivity improvement and construction of new hybrid antibiotics.

• Microbiology and Biotechnology Letters
• /
• v.38 no.1
• /
• pp.19-23
• /
• 2010

Recently, marine organisms are emerging as a leading group for identifying and extracting novel bioactive substances. These substances are known to possess a potential regarding not only as a source of pharmaceutical products but also their beneficial effects on humans. Among the substances, antimicrobial peptides (AMPs) specifically have attracted considerable interest for possible use in the development of new antibiotics. AMPs are characterized by relatively short cationic peptides containing the ability to adopt a structure in which cationic or hydrophobic amino acids are spatially scattered. Although a few reports address novel marine organisms-derived AMPs, their antimicrobial mechanism(s) are still remain unknown. In this review, we summarized the peptides previously investigated, such as Pleurocidin, Urechistachykinins, Piscidins and Arenicin-1. These peptides exhibited significant antimicrobial activities against human microbial pathogens without remarkable hemolytic effects against human erythrocytes, and their mode of actions are based on permeabilization of the plasma membrane of the pathogen. Therefore, the study of antimicrobial peptides derived from marine organisms may prove to be useful in the design of future therapeutic antimicrobial drugs.

• Archives of Pharmacal Research
• /
• v.27 no.5
• /
• pp.554-561
• /
• 2004

Trichostatin A, an antifungal antibiotics, and HC-toxin are potent and specific inhibitors of histone deacetylase activity. Histone deacetylase inhibitors are new class of chemotherapeutic drugs able to induce tumor cell apoptosis and/or cell cycle arrest. In this study, the antiproliferative activities of trichostatin A and HC-toxin were compared between estrogen receptor positive human breast cancer cell MCF-7 and estrogen receptor negative human breast cancer cell MDA-MB-468. Trichostatin A and HC-toxin showed potent antiproliferative activity in both MCF-7 and MDA-MB-468 cells. In MCF-7 cells that contain high level estrogen receptor, trichostatin A and HC-toxin brought about three-times more potent cell growth inhibitory effect than estrogen receptor negative MDA-MB-468 cells. Both trichostatin A and HC-toxin showed cell cycle arrest at G$_2$/M phases of MCF-7 and MDA-MB-468 cells in a dose- and time- depen- dent manner. Trichostatin A and HC-toxin also induced apoptosis from MCF-7 and MDA-MB-468 cells in a dose- and time-dependent manner. Results of this study suggested that antipro-liferative effects of trichostatin A and HC-toxin might be involved in estrogen receptor signaling pathway, but cell cycle arrest and apoptosis of trichostatin A and HC-toxin might not be involved in estrogen receptor system of human breast cancer cells.