• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.4
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• pp.412-418
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• 2001

The effects of dietary $\beta$-glucan administration on non-specific immune parameters in common carp, Cyprinus carpio, (1.0 g and 68.7 g of body weight) and flounder, Paralichthys olivcaces (12.1 g and 54.0 g of body weight) were evaluated. All fishes were fed an experimental diet supplemented with $\beta$-glucan at $0.1\%$ per kg diet for 5 weeks. A week intermission with basal diet occurred between first 2 weeks and second 2 weeks of $\beta$-glucan administration, The changes in the numbers of peripheral neutrophils and macrophages were counted under light microscopy and serum lysozyme activity was also analysed at a week of interval during the experiment. Phagocytic activities of leucocytes from the swimm bladder of carp and the peritonium of flounder were measured 5 weeks after feeding. The oral adminisration of $\beta$-glucan induced significant reduction in mortality after an artificial challenge with $1\times10^6$ cells of Aeromonas hydrophila in larger carp and $1\times10^5$ cells of Edwardsiella tarda in larger flounder but did not in other groups. The numbers of peripheral macrophages and neutrophils, phagocytic acitivies of leucocytes, and the activity of serum lysozyme were greatly increased in the fish fed a $\beta$-glucan supplemented diet. These suggest that $\beta$-glucan administration by oral route can enhance leucocyte phagocytic activity, serum lysozymal activity, and survival rate against artificial infections depending on the infected fish size and challenged bacterial concentration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.4
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• pp.470-475
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• 2007

Antibacterial activities of Scutellaria baicalensis Georgi (SBG) extract were examined against spoilage bacteria isolated from commercial tofu and various pathogens such as Listeria monocytogenes ATCC 19115, Pseudomonas fluorescens ATCC 21541. Staphylococcus aureus ATCC 29737, Salmonella Typhimurium ATCC 11806, Vibrio parahaemolyticus ATCC 17802, and Aeromonas hydrophila KCTC 2358. Four kinds of spore forming organisms were isolated from commercial tofu and identified as Bacillus sp. KN-4, Bacillus sp. KN-6, Bacillus sp. KN-10 and Bacillus sp. KN-20 using API CHB kit. The SBG extract showed high antibacterial activities and significantly inhibited the growth of the isolated spoilage bacteria and pathogens. The inhibitory effects against the organisms increased as the concentration of the SBG extract increased. The antimicrobial activities of the SBG extract were maintained markedly after heat treatments $(80^{\circ}C/30\;min,\;100^{\circ}C/30\;min\;and\;121^{\circ}C/15min)$. The minimum inhibitory concentrations (MIC) of the SBG extract against the organisms ranged from 1,000 ppm to 5,000 ppm.

• Korean Journal of Microbiology
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• v.43 no.2
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• pp.106-110
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• 2007

The detection and distribution of Aeromonas in water supplies were investigated by using the USEPA Method 1605. Water samples were collected from the Han River, finished waters and tap waters supplied from Water Treatment Plants in Seoul monthly from July 2002 to December 2003. Aeromonas species in each water sample were quantified based on the development of yellow colonies on the surface of membrane filter using a selective medium (Ampicillin-Dextrin Agar with Vancomycin). The Quality Control (QC) for this study met the acceptance criteria of Method 1605. The concentrations of Aeromonas species in surface water samples ranged from $1.0{\times}10^{0}\;to\;9.8{\times}10^{3}\;CFU/ml$. Aeromonas species were found only in one tap water sample with concentration of 1 CFU/500 ml. No Aeromonas species were found in any finished water samples. Aeromonas species detected here were identified as A. salmonicida(51%), A. caviae(4.7%), A. schubertti(3.4%), A. sobria(3.8%), A. hydrophila(2.1%), and A. ichithiosmia(0.4%). A. salmonicida was the dominant species, which is of no significance to human health. Chlorine resistance of A. salmonicida was evaluated and as a result, 99.99% of A. salmonicida decreased after 30 seconds exposure at residual free chlorine 0.2 mg/L. These suggest that the waters supplied in Seoul may be safe against the pathogenic agent Aeromonas.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.502-508
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• 1999

Microbiological characteristics of low salt Mul-kimchi was examined. Mul-kimchi was prepared by mixing of radish (25%), green onion (2.4%), red pepper (1.9%), garlic (1.9%) and salt (0, 0.2, 0.5, 1.0, 1.5, 2.0, 2.5, 2.5, 3.0%) in water and fermented at 4, 15 and $25^{\circ}C$ for 10 days, respectively. During fermentation period, total cell, Leuconostoc sp., Lactobacillus sp., Streptococcus sp., Pediococcus sp., coliform bacteria, gram (-) bacteria and yeast cell number were counted on their selection media. The microbes in Mul-kimchi were isolated and identified. Total cell number increased as salt concentration decreased and fermentation temperature increased. Lactic acid bacteria showed the highest number in 1.0% salt concentration. Yeast cell number increased with increase of salt concentration. Lactobacillus sp. were identified Lactobacillus plantarum and L. pentosus in Mul-kimchi containing $0.2{\sim}1.0%$ salt while those of Mul-kimchi containing 3.0% salt were Lactobacillus plantarum and L. brevis. The other lactic acid bacteria were identified Leuconostoc citrum, Leu.mes.ssp.mesenteroides/dextranicum and streptococcus facium in Mul-kimchi containing $0{\sim}3.0%$ salt while Pediococcus sp. was not detected. Gram-negative Aeromonas hydrophila, Pseudomonas fluorescens, Pseu. aureofaciens and yeast Candida pelliculosa, Cryptococcus laurentii were identified in the Mul-kimchi.

• Fisheries and Aquatic Sciences
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• v.19 no.10
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• pp.42.1-42.10
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• 2016

The objectives of this study were to identify the histamine-forming bacteria and bacteriocin- producing lactic acid bacteria (LAB) isolated from Myeolchi-jeot according to sequence analysis of the 16S rRNA gene, to evaluate the inhibitory effects of the bacteriocin on the growth and histamine accumulation of histamine-forming bacteria, and to assess the physico-chemical properties of the bacteriocin. Based on 16S rRNA gene sequences, histamine-forming bacteria were identified as Bacillus licheniformis MCH01, Serratia marcescens MCH02, Staphylococcus xylosus MCH03, Aeromonas hydrophila MCH04, and Morganella morganii MCH05. The five LAB strains identified as Pediococcus acidilactici MCL11, Leuconostoc mesenteroides MCL12, Enterococcus faecium MCL13, Lactobacillus sakei MCL14, and Lactobacillus acidophilus MCL15 were found to produce an antibacterial compound with inhibitory activity against the tested histamine-producing bacteria. The inhibitory activity of these bacteriocins obtained from the five LAB remained stable after incubation at pH 4.0-8.0 and heating for 10 min at $80^{\circ}C$; however, the bacteriocin activity was destroyed after treatment with papain, pepsin, proteinase K, ${\alpha}$-chymotrypsin, or trypsin. Meanwhile, these bacteriocins produced by the tested LAB strains also exhibited histamine-degradation ability. Therefore, these antimicrobial substances may play a role in inhibiting histamine formation in the fermented fish products and preventing seafood-related food-borne disease caused by bacterially generated histamine.

• The Korean Journal of Mycology
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• v.31 no.2
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• pp.67-76
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• 2003

This study was performed to screen antimicrobial activities of 198 extracts from 66 Korean mushrooms against 19 human pathogenic microorganisms using paper disc method. Mushrooms were extracted with petroleum ether 80% ethanol and distilled water in that order Among the extracts with antimicrobial activities, 1 water extract of Amanita virgineoides, 8 ethanolic extracts including Amanita and 1 petroleum ether extrac of Psathyrella hydrophila were highly active against fungi, respectively. In addition to, 24 extracts including Amanita pseudoporphyria, Amanita spissacea, 3 extaracts including Paxillus curtisii were highly active against Gram negative and positive bacteria, respectively.

• Journal of fish pathology
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• v.22 no.3
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• pp.391-400
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• 2009

Genetic identification of 17 fish-derived Aeromonas strains was attempted using 5 housekeeping genes. 16S rRNA, gyrB, rpoD, dnaJ and recA genes from the 17 strains were amplified, and total of 85 amplicons were sequenced. DNA sequences of the strains and type strains of the 17 Aeromonas homology groups were used for genetic identification and phylogenetic analyses. None of the strains was identified as a single species using the 16S rRNA gene, showing the same identities (average = 99.7%) with several Aeromonas species. According to gyrB, rpoD, dnaJ, and recA, 9 strains and RFAS-1 used in this study were identified as A. hydrophila and A. salmonicida, respectively. However, the other strains were closely related to 2 or more Aeromonas species (i.e., A. salmonicida, A. veronii, A. jandaei, A. media and A. troda) depending on the genetic marker used. In this study, gyrB, rpoD, dnaJ and recA gene sequences proved to be advantageous over 16S rRNA for the identification of field Aeromonas isolates obtained from fish. However, there are discrepancies between analyses of different phylogenetic markers, indicating there are still difficulties in genetic identification of the genus Aeromonas using the housekeeping genes used in this study. Advantages and disadvantages of each housekeeping gene should be taken into account when the gene is used for identification of Aeromonas species.

• Journal of Microbiology
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• v.41 no.2
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• pp.73-77
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• 2003

Four proteolytic bacteria were isolated and identified from a rotating biological contactor based on Bacillus. The four isolates, Ni 26, 36, 39 and 49 were identified as B. vallismortis, B. subtilis, Aeromonas hydrophila and B. amyioliquefaciens, respectively, based on their biochemical properties and 16S rDNA sequence analyses. The optimal proteolytic activity was observed in the temperature and pH ranges of 40-70$^{\circ}C$ and 8.0-8.5, respectively. The proteolytic activities of all the isolates were partially inhibited by phenylmethylsulfonylfluoride (PMSF), and the isolates Ni 26, Ni 39 and Ni 49 were inhibited by the metalloprotease inhibitor, 1,10-phenanthroline. Zymographic analyses of the culture supernatants revealed the presence of at least two pretenses in all isolates.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.2
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• pp.126-135
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• 2013

This study was performed to have an effect on control the growth of algae such as "Actinastrum fluviatile" which occurs frequently in the aquaculture tank using by a cold plasma, and it also would be expected to promote the growth of water plants due to active element causing OH radicals in the water. In addition, it was verified on the death rate as 99.9% on the scale protrusion of "Aeromonas hydrophila" as well as E. coli, especially, under extreme conditions more than 100 million pathogenic bacterium in the aqua pet tank, the ornamental fish had to act in a safe and healthy environment at over 98% death rate within 48 hours. It has been proven to give no affect on aerobic bacteria that exist in the filter or soil because there was no residual toxicity in the water tank. As the results, it will help to develop and apply on the sterilization device in other industries as well as aquarium organisms due to adopted energy-saving algorithm and reliability in use.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.5
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• pp.293-299
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• 2007

The distribution of hemolytic Vibrio sp. from sea water of three main beaches located in Busan (Gwangan(G), Haeundae(H) and Songjeong(S) beaches) was investigated from June to September 2006 ; this is mid-summer and the main season for bathing. The monthly detection ratio from each beach was 29.2% (7 of 24 samples, G), 33.3% (8 of 24 samples, H), and 16.7% (4 of 24 samples, S). The most probable number(MPN) of strains detected ranged from 1.8-36(G), 1.8-180(H) and 1.8-18(S) MPN/100mL. Of the isolated strains, 24 strains showed definite hemolytic activity. These 24 strains were identified as Vibrio fluvialis, Vibrio vulnificus, Aeromonas hydrophila, Actinobacillus ureae and Eikenella corrodens. Vibrio fluvialis was detected from all three beaches investigated. Vibrio vulnificus was detected from Haeundae and Gwangan beaches. Gwangan beach had a higher detection ratio of Vibrio sp. than Haeundae and Songjeong beaches. These results suggest that seafood harvested from the vicinity of theses beaches may cause food poisoning and risk management to prevent Vibrio septicemia is required, especially for Haeundae and Gwangan beaches.