• The Korean Journal of Food And Nutrition
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• v.13 no.6
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• pp.611-618
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• 2000

For the purpose of the isolation of microorganisms which have the capability of nitrification, we isolated the microorganisms in 6 samples collected from the stream of Kyonggi area. 60 strains were isolated. The selected strain were identified as a Aeromonas hydrophila based on the data obtained from the morphological, biochemical and cultural characteristics defined experiments. Among them Aeromonas hydrophila (AH-1), (AH-3) , (AH-4), (AH-6) showed the highest nitrification capability. All isolates were resistant to amoxillin, ampicillin, cephalothin and ticarcillin. Optimum culture conditions of isolates were 37$^{\circ}C$ and 1${\times}$10$\^$8/ cells/ml for 4 hours in the nitrate medium.

• Journal of Aquaculture
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• v.10 no.4
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• pp.439-447
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• 1997

A specific disease syndrome, which led to massive mortality on the Korean mandarin fish fingerling (Sinperca scherzeri) at Chongpyong Inland Fisheries Institute was atudied. The causetive agent isolated from the diseased fish was identified as Aeromonas hydrophila on the basis of biochemical and physiological characteristics. Infection experiments in the Korean mandarin fish fingerling, weighting 3-4 g with A. hydrophila were conducted by immersion, oral administration, intramuscular injection, and injection of the soluble extracellular products secreted from it. Motality rate was higher virulence in intramuscular injection group than other experimental groups. In injection group of the soluble extracellular products, all fish treated with high concentration ($8{\times}10^9$ cfu/ml) were repidly killed into 3-6 hrs. There results show that the Korea mandarin fish fingerling has high susceptibility to A. hydrophila.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.151-158
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• 1997

For the production of potent chitinolytic enzyme from bacteria, screening was carried out. Of 100 samples from soil, fresh water and sea water collected from the Kyung-gi area, 7 strains of chitinolytic bacteria were isolated. Among them, Aeromonas hydrophila 5-3K showed the highest chitinolytic activity. Culture conditions of Aeromonas hydrophila for the production of chitinolytic enzyme were inverstigated and lytic enzyme was fractionated by the use of ammonium sulfate and Sephadex G-100. Maximum production of chitinolytic enzyme was obtained at pH 7.0 and 30$\circ$C with chitin concentration between 0.2% and 1.0%. Conditions for the enzyme production were optimized including fermentor cultivation. The chitinolytic system of Aeromonas hydrophila 5-3K was composed of two enzymes, chitinase and chitobiase.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.251-256
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• 2001

To develop biofertilizer solubilizing inorganic phosphate, a bacterium having high abilities to solubilize inorganic phosphate were isolated from cultivated soils. The strain was identified to Aeromonas hydrophila DA57, based on the physiological and biochemical properties. The optimum temperature and initial pH to solubilize insoluvle phosphate in sucrose minimal medium were $30^{\circ}C$ and pH 7.0, respectively. In these conditions phosphate solubilizing activities of the strain against three types of insoluble phosphate were quantitatively determined. It was possivle to distinguish between solubilization through release of gluconic acid and still unknown mechanism. Aemmonas hydrophila DA57 harbored a 4.5 kb cryptic plasmid.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.325-334
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• 2009

Many bacteria that are capable to tolerate and degrade organic solvents have been isolated from seawater. However, their roles in the biodegradation of organic solvents in the marine environment have remained unknown. Aeromonas hydrophila IB$B_{ct4}$, isolated from Constanta seawater, was able to tolerate and degrade different organic solvents. Toluene, styrene, xylene isomers, ethylbenzene, with the logarithm of the partition coefficient in octanol-water mixture (log $P_{ow}$) between 2.64 and 3.17, were more toxic for bacterial cells, compared with propylbenzene, n-hexane, n-heptane, with log $P_{ow}$ between 3.69 and 4.39. There were revealed cellular and molecular modifications induced by organic solvents to Aeromonas hydrophila IB$B_{ct4}$. The study of cellular and molecular modifications induced by different organic solvents showed a complex response of bacterial cells to the presence of organic solvents in the culture media.

• Animal cells and systems
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• v.11 no.1
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• pp.33-38
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• 2007

Liposome-entrapped atypical Aeromonas hydrophila antigen was prepared to investigate the potential protective efficacy for A. hydrophila infection. Carp (Cyprinus carpio) were immunized orally with liposome-entrapped A. hydrophila antigen. After immunization, significantly more antigen-specific antibodies were detected in serum, intestinal mucus and bile than non-immunized control group. The immunized carp were then challenged by immersion with $1{\times}10^{6}$ cfu/ml of A. hyrdophila for 60 min. Of the eight non-immunized carp, three carp died (62.5% survival), whereas five out of six (83.5%) of the immunized survived. Furthermore, development of skin ulcers was significantly inhibited in carp immunized with liposomes containing A. hydrophila antigen. These results suggest that liposomes containing A. hydrophila antigen have a potential for induction of protective immune responses against atypical A. hydrophila infection and also suggest the possibility of developing a vaccine that may ultimately be used for prevention of fish diseases.

• Journal of environmental and Sanitary engineering
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• v.6 no.1
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• pp.31-46
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• 1991

Aeromonas hydrophila which bacause various diseases in human also infects fresh water fish, severly damaging the fishing industries. To prevent disease in humans and reduce damaging on the fishing industries, We have examined several characteristics of Aeromonas hydrophila and obtained the following results. All of the strains gave a posive voges-proskauer, methyl-red, salicin and esculin reaction. Seventeen(94.4%) A. hydrophila strains presented the phenotype SP-PAB- in autoagglut-ination test, but only strain AH 997 showed $SP^{+}PAB^{+}$. in autoagglut ination test, but only strain AH 997 $SP^{+}PAB^{+}$ All of the strains took up the censored to various degrees. Three of 18 strains showed positive reaction in crystal violet binding test. Hemolytic activity ranged from titers of 0 to 1/256. Seven of the 17(38.8%) A. hydrophila strains were positive in sucking mouse assay. Cytotoxin activity on vero and RK cells was displayed various titers.(1/2-1/1024)

• Journal of fish pathology
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• v.7 no.2
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• pp.113-117
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• 1994

The antimicrobial activity of Artemisia princeps var. orientalis essential oil against a partial fish pathogenic bacteria was examined. The growth of Aeromonas hydrophila, Aeromonas salomonicida, Aeromonas sorbia, Edwardsiella tarda and Streptococcus sp. (yellowtail) were inhibited at concentrations of 1,000 to 2,000 ppm. The A. salmonicida was inhibited at 1,000 ppm, A. hydrophila, A. sorbia, E, tarda and Streptococcus sp. (yellowtail) at 1,500 ppm, but Vibrio anguillarum, Vibrio ordalii, Edwardsiella ictaluri and Streptococcus sp. (SF 1) were grown on 100-2,000 ppm.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.187-195
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• 2022

Crucian carp, Carassius carassius (Weight 28.1±3.7 g, Length 10.0±1.0 cm) were challenged with Aeromonas hydrophila at 0, 2.0×10⁴, 2.0×10⁵, 2.0×10⁶, 2.0×10⁷ CFU/ml for 2 weeks. The lethal concentration 50 (LC₅₀) at 2 weeks of C. carassius challenged with A. hydrophila was 19.776×10⁵ CFU/ml. In hematological parameters, the hemoglobin and RBC counts were significantly decreased by A. hydrophila challenge, whereas there was no significant change in hematocrit. The inorganic plasma components such as magnesium and calcium were significantly decreased. In organic plasma components, glucose and cholesterol were significantly increased by A. hydrophila challenge, whereas total protein was significantly decreased. In enzymatic plasma components, ALP (Alkaline phosphatase) were significantly increased by A. hydrophila challenge. The results of this study suggest that the A. hydrophila challenge to C. carassius induced the significant physiological changes in the hematological parameters and plasma components as deadly pathogenic bacteria.

• Journal of fish pathology
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• v.10 no.1
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• pp.31-38
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• 1997

Aeromonas hydrophila isolated from the intestine of carp produced several kinds of proteases into the medium. Inhibitor assay with the culture supernatant of A. hydrophila showed that there were major metalloproteases and minor serine proteases. Gelatin SDS-PAGE showed two proteolytic bands. One broad protease band was inhibited by metalloprotease specific inhibitor, EDTA, indicating a metalloprotease. The other was inhibited by serine protease specific inhibitor, PMSF, suggesting a serine protease. The proteolytic activities of both extracellular proteases remained on Gelatin SDS-PAGE after heating at $70^{\circ}C$ for 30 min. However, the major metalloprotease was separated into two proteolytic bands on Gelatin PAGE by gel filtration chromatography on Sephadex G-75.