• Journal of fish pathology
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• v.3 no.1
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• pp.1-9
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• 1990

The present study was carried out to reveal the characteristics of organism responsible for so called vibriosis prevailing in warm water season among cultured kuruma prawn Penaeus japonicus. A bacterium was isolated from the heart, lymphoid organ and muscle of the diseased kuruma prawn. Six strains obtained from diseased kuruma prawn in some culture farms in Namhae and Anhung from august to october in 1989 were submitted to the morphological, biochemical and physiological characterization. All the strains were gram-negative, nonsporning short rods with one polar flagellum. Glucose was fermented with no gas production by these strains. Some distinguishing features of the organisms were negative to lysine, arginine, ornithine decarboxilization test. In general, the temperature $20{\sim}27^{\circ}C$, the NaCl concentration of 2~3% and pH of 6~8 were optimal for the growth in peptone water. The organisms were sensitive to the vibrio static agent 0/129. The isolated should be identified as Vibrio sp.. No essential differences in histopathological finding were noted between the naturally and the experimentally infected prawns. Most characteristic pathological changes were extensive necrosis caused by severe bacteria invasion and multiple formation of meranized nodules in the lymphoid organ.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.77-81
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• 1998

A bacteriological study of sea water in Deukryang Bay was conducted to evaluate sanitary conditions of the bay and compliance of waters with the recommended bacteriological criteria for the designated area of shellfish cultivation. Sea water samples were collected at the established sampling stations (fig. 1) from May 1995 to November 1996. During the study period, coliform group, fecal coliform, classification of coliform group with IMViC reactions and pathogenic vibrios were analyzed. Coliform group and feral coliform MPN's were ranged from $<\;3.0\~4600/100m{\ell}\;and\;<\;30\~1,100/100m{\ell}$, respectively. The bacteriological criteria of sea water in shellfish growing area should be less than 70 per l00ml of sea water for median value of coliform MPN, and below $10\%$ of the samples which contain over than 230 for coliform MPN or over than 43 for fecal coliform MPN, Most of the waters from 26 sampling stations were complied water coliform criteria recommended for designated shellfish growing area. Then, the ratios of the samples with move than 230/10ml of coliform group MPN and more than 43/100ml of fecal coliform MPN were $7.4\%$ and $8.5\%$, respectively. The bacterial density of the sea water was deeply affected by rainfall amount. For example, coliform bacterial counts of sea watery after 48 hours from 93 mm rainfall were $6\~7$ times higher than those of without rainfall. During the study period, infectious bacteria such as Vibrio cholerae, Salmonella sp. an d Shigella sp. were not detected from the samples, but detection ratios of Vibrio parahaemolyticus and Vibrio vulnificus were $15\~20\%$ in summer months.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.127-134
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• 2018

In this study, 79 bacterial isolates were collected from the surface of marine algae Umbraulva japonica. As a result of analysis of 16s rRNA gene sequence, the 79 isolated bacteria were divided into 4 major groups: [Proteobacteria (74.69%), Actinobacteria (2.53%), Fimicutes (2.53%), and Bacteroidetes (20.25%)] - 7 classes (Actinobacteria, Flavobacteria, Sphingobacteria, Baciili, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria), 12 orders, 17 families and 31 genera. The newly isolated 3 strains could be novel species because of less than 97% similarity in 16s rRNA sequence. Therefore, it is considered that additional experiments should be conducted together with the standard strain. Analysis of 79 bacterial antibacterial activity against human and fish pathogens, such as Edwardsiella tarda, Vibrio harveyi, Streptococcus iniae, Steptococcus parauberis, Escherichia coli, Steptococcus mutans, Listeria monocytogenes and Vibrio vulnificus, was performed by using the supernatant liquid and pellet. As a result, pellet of UJT9, UJT20 and UJR17 showed antibacterial activity against V. vulnificus, UJR17 also showed antibacterial activity against S. parauberis. UJT7 and UJT20, UJR17 have been identified as Bacillus sp. and Pseudomonas sp. and it may be safely assented that it's beneficial to carry out additional experiments for various applications.

• Journal of fish pathology
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• v.23 no.1
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• pp.27-35
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• 2010

Pathogens on the cultured 579 rockfish, Sebastes schlegeli in the marine cage farms from Geoje and Tongyeong of the Southern sea were investigated from 2006 to 2008. The pathogens were detected throughout the year at 46.0~90.0% for 3 years and the detection rate was low with an average 58.1% in May and high with an average 81.5% in October. Bacteria only, bacteria-parasite mix and virus only were found in October and November as well as parasite only, whereas infection of parasite only was dominant in May when the temperature increased and in August when the temperature peaked. Of rockfish, Microcotyle sp. and Caligus sp. were dominant for parasitic disease, and Vibrio sp. and Streptococcus sp. were dominant bacteria. For virus, RSIV and VNNV were detected as dominant organisms. While no virus was detected in 2006, VNNV, VHSV and RSIV were detected in 2007 due to $1.5\sim2.0^{\circ}C$ higher temperature than 2006 in the summer season. For total prevalence by rockfish sizes, the highest was found at 50.0~87.1% in 11~15cm sizes and 50% was found in 30 cm size. Parasite showed a similar trend of 50.0~79.6% as the total prevalence. Prevalence for bacteria varied from 1.6% (for 10 cm group) to 23.8% (for 26 cm group) and higher virus prevalence of 21.5% was found from below 25 cm group.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.40-48
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• 2016

This study mainly focused on isolation of marine algicidal bacteria associated with phytoplankton blooms and characterization of algicidal activity against harmful algae. Harmful algal blooms (HABs) found naturally in surface waters have caused many environmental problems worldwide. In this study, forty bacterial strains that have capability of inhibiting harmful algal growth were isolated from Masan Bay, Jinhae Bay, Dol Island, Jangmok Bay, and the Tongyeong Sea, Republic of Korea. The bacteria were screened furthermore for the characteristics on algicidal activities against Cochlodinium polykrikoides, Chattonella marina, Skeletonema costatum, Heterosigma akashiwo, Heterocapsa triquetra, Prorocentrum minimum, and Scrippsiella trochoidea. As a result, the algicidal bacteria that were screened from double over layer agar and microscopic counts tests belonged to genera Pseudomonas, Vibrio, Bacillus, Pseudoalteromonas, Ruegeria, Joostella, Marinomonas, Stakelama, Porphyrobacter, and Albirhodobacter. One of the most important HAB species is Co. polykrikoides and the strongest algicidal activity against the dinoflagellate was 94.00% after 6 h treatment with 10% bacterial culture filtrate. In this study, Marinomonas sp. M Jin 1-8, Stakelama sp. ZB Yeonmyeong 1-11 & 1-13, Porphyrobacter sp. M Yeonmyeong 2-22, and Albirhodobacter sp. 6-R Jin 6-1 were found to be as new genera of bacteria having anti-algal activity. These results suggest that these bacteria might play an important role in controlling phytoplankton blooms.

• Journal of Microbiology and Biotechnology
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• v.5 no.4
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• pp.181-187
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• 1995

The cells of Vibrio vulnificus can be induced to the viable but nonculturable (VBNC) state by natural environmental parameters. The V. vulnificus cells in the VBNC state can not be recovered by ordinary laboratory techniques. This nonculturability could often hamper development of effective processing strategies to minimize the number of V. vulnificus in seafoods. Even with V. vulnificus cells in a culturable state, the length of time required to identify the bacteria in contaminated food by phenotyphic characterization may prevent appropriate in-time responses by public health agencies to infections of the bacteria. In the present study, we used polymerase chain reaction (PCR) to develop a rapid and direct detection method for V. vulnificus in small octopus (Octopus variabilis) which is consumed as a raw food in Korea. The region targeted was a 704-base pair (bp) portion of the hemolysin gene, vvhA, of V. vulnificus. The primers designed for PCR amplification were specific for all V. vulnificus sp. tested. Several methods were examined to extract total DNA directly from V. vulnificus seeded into the octopus homogenate and the guanidine isothiocyanate (CITC) method appeared to be most effective. From the octopus homogenate seeded by V. vulnificus at an initial level of $10^2$ CFU/ml of the homogenate and then incubated for 12 h, the targeted sequence was successfully amplified by PCR and the 704-bp DNA fragment was observed by gel electrophoresis. The total completion of this assay requires less than one day.

• Microbiology and Biotechnology Letters
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• v.47 no.3
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• pp.459-464
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• 2019

This study aimed to identify and characterize the antimicrobial activity of prodigiosin produced by Serratia sp. $PDGS^{120915}$ isolated from stream water in Busan, Korea; the identification was performed using phonological, biochemical, and molecular techniques, including 16S rRNA sequence analysis. Prodigiosin from the bacterial culture was purified by high-performance liquid chromatography (HPLC), and its antimicrobial activity and minimum inhibitory concentrations (MICs) were evaluated against 10 intestinal pathogenic gram-positive and negative bacteria. The results revealed that the isolated prodigiosin exhibited high antimicrobial activity against Listeria monocytogenes, Bacillus cereus, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, and Vibrio parahaemolyticus; further, the isolated prodigiosin showed minimum inhibitory concentrations (MICs) between $3{\mu}g/ml$ and 30 mg/ml, but they were not active against Bacillus subtilis, Enterococcus faecalis, Klebsiella pneumonia, and Escherichia coli. In conclusion, prodigiosin isolated from Serratia sp. $PDGS^{120915}$ showed high antimicrobial activity against intestinal pathogenic bacteria and has potential applications in the development of new antimicrobial agents.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.971-975
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• 2008

This study was to examine the potential disinfection efficiencies of 10 compounds by determining their antimicrobial capacity and ichthyotoxicity. Antimicrobial effects against Vibrio sp., Edwadsiella tarda, Streptococcus sp., and Staphylococcus sp. were tested using 10 different disinfectants; hydrogen peroxide, sodium hypochlorite, chlorine dioxide, povidon iodine, formaldehyde, glutaraldehyde, quaternary ammonium compounds (QACs), didecyl dimethyl ammonium chloride (DDAC), ortho-dichlorobenzen, and copper sulfate. Chlorine dioxide ($ClO_2$) containing 5% $ClO_2$ and copper sulfate had no effects on bactericidal activity, while the other disinfectants resulted in 99.99% bactericidal activity against 4 strains of fish pathogenic bacteria. The ichthyotoxicity of the 10 disinfectants was investigated using 3 kinds of fish species; flounder (Paralichthys olivaceus), rockfish (Sebastes pachycephalus), and black sea bream (Acanthopagrus schlegelii). Median lethal concentration ($LC_{50}$) values of the 10 disinfectants were estimated to determine toxicity ranges of the doses within 24 hr. Among test disinfectant solutions, hydrogen peroxide showed the highest $LC_50$ in flounder (201.3), rockfish (269.7), and black sea bream (139.3 ppm). DDAC revealed the lowest $LC_{50}$ in flounder (2.1), rockfish (1.0), and black sea bream (1.5 ppm). These results suggest that DDAC, quaternary ammonium compounds, glutaraldehyde, and sodium hypochlorite are effective disinfectants for fish and bacterial species examined in this study.

• Journal of fish pathology
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• v.17 no.3
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• pp.159-169
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• 2004

Bacterial wihte enteritis ocurred by infection of V. ichthyoenteri is a devastating disease in olive flounder (Paralichthys olivaceus) hatcheries in Korea. Since white enteritis has been a problem in aquqtic industries, necessity of a rapid detection method is increased. In an attempt to develop rapid PCR method the detection of V. ichthyoenteri, we examined the 16S-23S rRNA intergenic spacer region(ISR) of V. ichthyoenteri and developed species-specific primer for V. ichthyoenteri. The intergenic spacers were amplified by primers complementary to conserved region of 16S and 23S rRNA genes. The intergenic spacer region between the 16S and 23S rRNA genes of V. ichthoenteri were investigated by PCR fragment length typing and DNA sequencing. Analysis of the ISR sequences showed that V. ichthyoenteri contains one types of polymorphic ISRs. The size of ISRs ranged 348bp length and not contains tRNA genes. Mutiple alignment of representative sequences from different Vibrio species revealed several domains of high sequence variability, and allowed to design species-specific primer for detection of Vibrio ichthyoenteri. PCR. The specific of the primer was examined using genomic DNA prepared from 19 different Vibrio species, isolated 18group Vibrio species. The results showed that the PCR reaction using species-specific primer designed in this study can be used to detect V. ichthyoenteri.

• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.424-431
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• 2011

BACKGROUND: Tributyltin chloride is among the most toxic compounds known for aquatic ecosystems. Microorganisms are responsible for removal of TBTCl. Nevertheless, only a limited number of marine bacteria were investigated for biodegradation of TBTCl in Korea. METHODS AND RESULTS: The number of TBTCl resistant bacteria ranged from $2.5{\times}10^3$ to $3.8{\times}10^3$ cfu/mL in the seawater, and ranged from $3.2{\times}10^5$ to $9.1{\times}10^5$ cfu/g in the surface sediment, respectively. The morphological, physiological, and biochemical characteristics of TBTCl resistant bacteria were investigated by API 20NE and other tests. The most abundant species of TBTCl resistant bacteria were Vibrio spp. (19.2%), Bacillus spp. (16.2%), Aeromonas spp. (15.2%), and Pseudomonas spp. (13.1%), etc. Eleven TBTCl resistant isolates also had a resistance to heavy metals (Cd, Cu, Hg, and Zn). Among them, isolate T7 showing the strong TBTCl-resistance was selected. This isolate was identified as the genus Pantoea by 16S rRNA gene sequencing and designated as Pantoea sp. T7. In addition, this bacterium was cultivated up to the growth of 50.7% after 60 hrs at TBTCl concentration of $500{\mu}M$. TBTCl-degrading activity of Pantoea sp. T7 was measured by GC-FPD analysis. As a result of biological TBTCl-degradation at TBTCl concentration of $100{\mu}M$, TBTCl-removal efficiency of Pantoeasp. T7 was 62.7% after 40 hrs. CONCLUSION(S): These results suggest that Pantoea sp. T7 is potentially useful for the bioremediation of TBT contamination.