• Journal of Life Science
• /
• v.33 no.11
• /
• pp.915-922
• /
• 2023

Lactic acid bacteria (LAB) are widespread in a variety of environments including fermented dairy products, gastroinstetinal and urogenital tracts of human and animals, plant, soil and water. Leuconostoc mesenteroides DB3 was detected by the strongest antibacterial activities among 24 Leuconostoc strains isolated from Camellia japonica flowers. Acid tolerance of L. mesenteroides DB3 existed up to pH 2.5, but the resistance did not show at pH 2.0, which relatively excellent acid resistance existed. Bile acid tolerance was very stable within the test range to 1.2%. L. mesenteroides DB3 exhibited the optimal growth at 30℃, and showed a slight slow growth when compared with L. mesenteroides KCTC3505, which reached a stationary phase at 18 hr. The pH was changed along with the growth curve, but was maintained above pH 3.98. L. mesenteroides DB3 had higher initial antibacterial activities when compared to L. mesenteroides KCTC3505, but it showed similar activities with the standard strain after the latter part of the logarithmic growth phase. Although lactic acid production in L. mesenteroides DB3 was induced by lower amount in the initial part to the standard strain, it was exhibited by similar amounts after the late logarithmic growth phase. Muicin adhesion of L. mesenteroides DB-3 maintained superior to L. mesenteroides KCTC3505. Both strains showed excellent emulsification ability for kerosene. In summary, we evaluate that L. mesenteroides DB-3 has a high potential for application as probiotics owing to its excellent antibacterial activity, acid resistance, bile acid resistance, and muicin adhesion.

• Applied Biological Chemistry
• /
• v.27
• /
• pp.29-46
• /
• 1984

To utilize several species of hard wood as raw materials of feed products, fermentation characteristics of cellulosic substrates to single cell protein was investigated, and results were summarized as follows. Among the microorganisms investigated, Tricoderma viride was selected as one of the most cellulolytic. Mixed culture of fungi did not show a synergistic effect on cellulose degradation. When the fungi were cultured at $28^{\circ}C$ for 7 days in a medium containing wheat bran 25 g, cellulose 0.25 g, proteose peptone 0.025 g and tween 800.025 g, cellulotic activities on carboxy methyl cellulose and filter paper reached maximum at 12 hr. The alkali treatment resulted in increased degradation of substrate from 13 to 18% when treated with enzymes for 12h, and reducing sugar formation increased with decreased size of substrates. Glucose was a very good feedback inhibitor of the enzyme from T.viride than that of xylose. When the substrate was rehydrolyzed, hydrolysis rate was 31% to reducing sugars within 12 hr. Quantative anlysis with HPLC showed the ratio of glucose to xylose in sugar syrups as 1.77 to 1. For the purpose of producing cellulosic-single cell protein from the sawdust of mulberry tree, 15 strains of xylose-assimilating yeast were isolated from 42 samples of rotten woods and compost soils and examined for their ability to utilize xylose. Then three strains were selected by their strong xylose-assimilating activities. The cultivative condition, the growth characteristics, and protein and nucleic acid productivities of three strains were investigated. The results obtained were, 1. Wood hydrolysate of mulberry tree was assimilated by 5 strains of CHS-2, CHS-3, ST-40, CHS-12 and CHS-13. 2. The optimum initial pH and temperature for the growth of strain CHS-13 were 4.4 and $30^{\circ}C$. 3. The specific growth rate of strain CHS-13 was $0.23h^{-1}$ and generation time was 3.01 hrs at the optimum condition. 4. CHS-13 strain assimilated 81 % of sugar in wood hydrolysate. 5. CHS-13 strain was identified as Candida guilliermondii var. guilliermondii 6. When the CHS-13 strain was cultured in the wood hydrolysate containing yeast extract, L-protein content was increased with yeast extract concentration. 7. The L-protein and nucleic acid yields from wood hydrolysate were 0.73 mg/ml and $4.92{\times}10^{-2}\;mg/ml$ respectively. 8. An optimal nucleic acid content of CHS-13 strain was observed in the medium containing 0.2% of yeast extract.

• Research in Plant Disease
• /
• v.17 no.3
• /
• pp.280-287
• /
• 2011

This investigation was undertaken to survey toxigenic fungal contamination of various rice samples in 93 rice processing complexes (RPC) in Korea. Rice was grown in 2009 and the samples were collected in 2010. Seven types of rice samples such as unhusked, brown, blue-tinged, discolored, polished, half-crushed, and rice husks were obtained from each RPC. One-hundred and five grains of each sample were placed on PDA plates after surface disinfection. The incidence of fungal contaminants was 26.8%. Aspergillus spp. was the most dominant fungal contaminants and Fusarium spp. was the most frequently occurred in samples. The heaviest Fusarium contamination was found in unhusked grain, rice husks, and bare blue-tinged rice and followed by colored rice whereas broken rice was the least contaminated. Regional difference of fungal contamination was distinctive. Fusarium incidence in the rice samples from southern region of Korea including Jeolla and Gyeongsang Provinces was higher than those from central region including Chungcheong, Gyeonggi, and Gangwon Provinces. In contrast to Fusarium spp., Aspergillus spp. and Penicillium spp. were dominated in brown and polished rice samples and their incidences were more severe in central region than southern region. The major contaminants shown more than 1% of kernels infected were Aspergillus (5.0%), Fusarium (2.0%), Alternaria (1.4%), Dreschlera (1.3%), Penicillium spp. (1.3%), and Nigrospora spp. (1.0%). Collectotrichum, Pyricularia, Myrothecium, Epicoccum, Cladosporium, Moniliella, Gloeocercospora, Chaeto- mium, Curvularia, Phialopora, Acremonium, Gliomastix, Trichoderma, Rhizopus, Phomopsis, Paecilomyces, Genicularia, Geotrichum, Acremoniella, Rhizoctonia, Phoma, Oidiodendran, and Candida spp. were among the rest observed at low incidence. The major contaminants of rice samples were well-known as toxigenic fungal genera so toxin producibility of these fungal isolates is necessary to be examined in future. It is also needed to study Myrothecium spp. on species level as it was detected for the first time in rice.

• Clinical and Experimental Pediatrics
• /
• v.45 no.8
• /
• pp.1000-1006
• /
• 2002

Purpose : In the course of treatment, patients with hematological or oncological disorders often develop pulmonary complication. The patients who develop a severe pulmonary complication have a poor outlook. The causes of pulmonary complication are either infectious or non-infectious in origin. We have analyzed the etiology and outcome of these patients admitted to the pediatric intensive care unit of Asan Medical Center. Methods : Medical records of 95 patients on Pediatric oncology service who were admitted to pediatric intensive care unit(PICU) of Asan Medical Center from Jan 1997 to May 2000 were retrospectively reviewed. Results : The mean age of the patients was 8.5 years(2 months-18 years). The underlying malignancies of these 95 patients were as following; acute lymphoblastic leukemia(31 cases), lymphoma (11 cases), acute myeloid leukemia(nine cases), brain tumor(eight cases) and other solid tumors(25 cases). Pulmonary complications included pneumonia, acute respiratory failure, pneumothorax and pleural effusion. The most common cause of pulmonary complication was infection(88%) in etiology. The overall mortality rate was 56.8%. Pulmonary complications in these patients carried high rates of mortality regardless of whether they were immune compromised(76%) or not(69%). Even without pulmonary complications, the hematological or oncological patients admitted to PICU had high mortality rates of 43%. Conclusion : Pulmonary complications are frequent finding in the hematological or oncological patients admitted to Intensive Care Unit. The main etiology of these pulmonary complications was infection, which carried a high mortality rate regardless of their immune status at the time when they were admitted to PICU.

• Microbiology and Biotechnology Letters
• /
• v.38 no.2
• /
• pp.190-197
• /
• 2010

To develop the safe and natural antimicrobial agents, the 68 ethanol extracts from the 61 different kinds of oriental herbal medicine were prepared and their antimicrobial activities were evaluated. The herbal medicine used were from China (46 kinds), South Korea (14 kinds), North Korea (5 kinds) and Vietnam (3 kinds), respectively, and the root (27 species) was popular part in this study. The average water content and extraction ratio for ethanol were 7.10% and 6.75%, respectively. Determination of antimicrobial activity by disc-diffusion assay at 0.5 mg/disc concentration showed that the extract of Angelica tenuissima Nakai (china), Illicium verum, Junci medulla, Rhus javanica L., Salvia miltiorrhiza Bunge and Syzygium aromaticum has strong antimicrobial activities against different food spoilage and pathogenic bacteria and fungi. Determination of MIC and MBC/MFC further showed that the extract of Syzygium aromaticum has MIC of 1.25 mg/mL and MBC/MFC of 1.25~5.00 mg/mL against Listeria monocytogenes, Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus, Salmonella typhimurium, Proteus vulgaris, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Saccharomyces cerevisiae. And, the extract of Junci medulla, Rhus javanica L. and Salvia miltiorrhiza Bunge showed strong antibacterial activities with MIC of 0.08~0.63 mg/mL and MBC/MFC of 0.08~2.50 mg/mL against the tested bacteria except E. coli and P. aeruginosa. In a while, the results of hemolytic activity of 68 different herbal extracts against human red blood cells showed that the extract of Angelica tenuissima Nakai has hemolytic activity at 0.5 mg/mL concentration. Therefore, Illicium verum, Junci medulla, Rhus javanica L., Salvia miltiorrhiza Bunge and Syzygium aromaticum were finally selected for natural antimicrobial resources. Further research on active substances and the mode of action of the selected herbal medicine is necessary.

• Journal of Sericultural and Entomological Science
• /
• v.53 no.2
• /
• pp.135-142
• /
• 2015

The American cockroaches, Periplaneta americana L. was the most important worldwide pest species. It has been an public health problems. We were determinated life cycle and extraction of crude extracts by chemical reagents from cockraches (P. americana L.). The extracted crude solution has been antibacterial activity to gram negative bacteria (Pseudomonas aeruginosa, $6.44{\pm}1.03mm$), gram positive bacteria (Bacillus subtilis, $1.88{\pm}0.40mm$), and fungus (Candida albicans, $5.61{\pm}0.57mm$) using radial diffusion assay. We were analysed of up-regulation of Glutathione-S-transferases (GSTs) stimulation, indicating that antioxidantial protein from various classes are simultaneously expressed in a single insect upon infection or injury. The gene from Periplaneta americana L. were cloned, analysed sequence, and measured protein expression by Real Time PCR (Polymerase Chain Reaction).