• Journal of Life Science
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• v.24 no.4
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• pp.428-436
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• 2014

Loop-mediated isothermal amplification (LAMP) technique relies on autocycling strand displacement DNA sysnthesis without template denaturation steps under isothermal conditions. LAMP has more advantages than modern PCR, as it requires only basic laboratory equipment like an isothermal water bath, oven, and heating cabinet. Hence, in this study, five random primers were designed with Streptococcus parauberis, shikimate kinase Arok gene sequences (Genbank accession number: CP0024711). Two primers were selected based on the ladder pattern. Other optimum reaction conditions like temperature, time, and sensitivity were established and confirmed with conventional SYBR-green PCR. Results confirmed that the designed random primers were species specific, without any non-target DNA amplification under isothermal conditions. Hence, this study suggests that LAMP techniques could be used in the diagnosis of fish pathogen, specifically S. parauberis.

• Journal of fish pathology
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• v.20 no.3
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• pp.201-209
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• 2007

Viral hemorrhagic septicemia (VHS) is one of the most serious viral disease of farmed rainbow trout and some marine fishes in Europe and North America. It has been reported in various marine fish species of Asian countries and induced cause mass mortality in Japanese flounder (Paralichthys olivaceus) culturing in Korea. The aims of this study were to monitor VHSV in wild marine fishes and to give critical information for controling the disease through prophylactic methods. Prevalence of the viral disease, geological distribution and reservoir of the virus were investigated using wild marine fishes captured in southern coast and east china sea for two years. (Reverse Transcriptase Polymerase Chain Reaction) RT-PCR results showed that VHSV were detected in 17 (10.6%) out of 160 fish. G gene sequences of viral strains isolated in this study were closely related to that of a reference strain, KVHS01-1, belonging to VHSV genotype Ⅰ. The results suggest that some of wild marine fishes are VHSV carriers and may spread the pathogen directly to fish farmed in coastal area.

• Journal of fish pathology
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• v.20 no.3
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• pp.211-220
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• 2007

Red sea bream iridovirus disease (RSIVD) cause massive economic losses in marine aquaculture industry in Korea. The causative agent of this disease (RSIV) infects a wide range of fish species. The aims of this study were to monitor RSIV in wild marine fishes and to give critical information for controling the disease through prophylactic methods. Prevalence of the viral disease, geological distribution and reservoir of the virus were investigated using wild marine fishes captured in southern coast and east china sea for two years. (Polymerase Chain Reaction) PCR results showed that RSIV were detected in 39 (24.3%) out of 160 fish. MCP gene sequences of viral strains isolated in this study were closely related to that of a reference strain, red seabream-K, belonging to Megalocytivirus subgroup Ⅲ. The results suggest that some of wild marine fishes are RSIV carriers and may spread the pathogen directly to fish farmed in coastal area.

• Journal of Life Science
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• v.24 no.8
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• pp.880-886
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• 2014

In this study, we isolate and identify bacteria from seawater collected from Jeju coast, to evaluate the antimicrobial activity against the fish pathogenic bacteria. 14 bacterial strains were isolated and identified using physiological, biochemical and molecular tools. Antibacterial activity of all the 14 isolates were screened against four major fish pathogens namely, two Gram-positive: Streptococcus iniae, Streptococcus parauberis and two Gram-negative: Vibrio anguillarum, Edwardsiella tarda. Results revealed that among the 14 isolates, MK-11 was found to have antibacterial activity against S. iniae, S. parauberis, V. anguillarum Particularly, S. iniae was susceptibility with the MIC value of $250{\mu}g/ml$. The biochemical and physio-chemical results reveal that MK-11 had the sugar-alcohol disassemble ability of the D-sorbitol and D-mannitol. Also the utilization of the yeast extract, sorbitol and di-potassium phosphate were noted to be high. The optimum culture condition such as pH and temperature was recorded as pH 6.0, $25^{\circ}C$ and along with 1% NaCl which differs from the previous reports particularly in nutrient resolutions. As results of the analysis of 16S rDNA sequences, MK-11 show the high similarity with Paenibacillus polymyxa, P. jamilae, P. brasilensis 99.78%, 99.43%, 99.39%, repectively. Hence, in the present study, the isolated Paemibacillus sp. MK-11 from Jeju seawater possesses the antibacterial activity against fish pathogens and it could be used as a new antibiotic agents against the gram positive fish pathogens.

• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.109-117
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• 2024

This study investigated the microbial contamination of agricultural, livestock, and marine ingredients in 55 meal kits distributed across Gyeonggi-do, South Korea. Of the 55 meal kits, 48 contained agricultural ingredients, 43 contained livestock ingredients, and 16 contained marine ingredients. The detection rate of the total aerobic bacteria in the agricultural, livestock, and marine products was 100%. The average numbers of the total aerobic bacteria were 6.57 log colony-forming units (CFU)/g in the agricultural products, 4.60 log CFU/g in the livestock products, and 5.47 log CFU/g in the marine products. The coliform detection rates in the agricultural, livestock, and marine products were 81.25%, 69.77%, and 43.75%, respectively. The average numbers of coliforms were 2.83 log CFU/g in the agricultural products, 1.34 log CFU/g in the livestock products, and 1.12 log CFU/g in the marine products. Escherichia coli was detected in 13 livestock products (30.23%), with levels ranging from 0.70 to 2.36 log CFU/g. Contrastingly, E. coli was detected in only one marine product (6.25%) and was not detected in any agricultural products. The detection rates of fungi in agricultural, livestock, and marine products were 97.92%, 93.02%, and 93.75%, respectively. The average numbers of fungi were 3.82 log CFU/g for the agricultural products, 2.92 log CFU/g for the livestock products, and 2.82 log CFU/g for the marine products. The isolation rates of foodborne pathogens from the agricultural, livestock, and marine products were 35.42%, 37.21%, and 31.25%, respectively. Forty-five foodborne pathogens of seven species, including Bacillus cereus and Salmonella spp., were isolated from the raw materials of the agricultural, livestock, and marine products in 55 meal kits. To prevent foodborne diseases caused by meal kits, it is necessary to focus on washing, heating, and preventing cross-contamination during cooking.

• Natural Product Sciences
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• v.20 no.1
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• pp.39-43
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• 2014

Papenfussiella kuromo (PK) is a marine plant and an abundant ecological resource for the future; it is found in almost 80% of the terrestrial biosphere. The aim of this study was to investigate the antibacterial activity of PK against methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant pathogen. The minimum inhibitory concentrations (MICs) of PK hexane fraction (PKH) against 7 strains of MRSA ranged from 1.0 to 2.0 mg/mL. In the checkerboard dilution method, a synergistic effect of the PKH and the antibiotics (oxacillin and norfloxacin) was seen. PKH markedly reduced the MIC of each of the 4 antibiotics against MRSA. The time-kill assay showed that the synergistic activity of PKH and an antibiotic reduced the bacterial counts below the lowest detectable limit after 24 h. These findings suggest that PKH has antibacterial activity, and may be important baseline data in future extensive studies of living marine resources as a source of compounds active against MRSA.

• Journal of Aquaculture
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• v.18 no.3
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• pp.207-214
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• 2005

We report on the diagnosis, pathology, and taxonomy of Perkinsus sp. infection in Manila clams (Ruditapes philippinarum) from Korean waters. Amplimers were designed from internal portions of the non-transcribed spacer (NTS) of P. atlanticus for molecular diagnosis of Perkinsus infection. PCR-based identification methods and an in situ hybridization assay were developed for detection of Perkinsus sp. in live tissues as well as in histological preparations. Hybridization signals were observed around the nucleus of trophozoites. Positive results from PCR and in situ hybridization indicated that Korean Perkinsus sp. is genetically identical with P. atlanticus reported in Europe, which is currently synonymous with P. olseni reported from Australia. Microscopic morphological features of different lift stages of Perkinsus sp. appeared very similar to those of P. atlanticus. Severely infected clams often exhibited white nodules on their mantles and gills as a consequence of inflammation. In lightly to moderately infected clams, Perkinsus sp. was mainly found in gill tissues, whereas the protozoan parasites were found in digestive tracts, gonadal tissues, and foot tissues of heavily infected clams. It is likely that the gills are the portal of the infection and that P. olseni spreads to other tissues as the infection advances. In conclusion, by considering the taxonomic priority of P. olseni, Korean Perkinsus sp. is accepted as P. olseni. P. olseni appears to be common on tidal flats on the western and southern Korean coasts and is considered to be a pathogen capable of causing mass mortality of clams.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.369-378
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• 2018

This study was conducted to evaluate effects of dietary microbial probiotics on the growth and disease resistance of olive flounder (Paralichthys olivaceus) in a recirculating aquaculture system (RAS), and the effects of the probiotic bioaugmentation on the microbial community structure and water quality. For the analysis, 80 juvenile fish (average weight, $25.7{\pm}7.6g$; average length, $15.2{\pm}1.7cm$) were fed a basal diet containing a commercial microbial product CES-AQ1 (CES; $1{\times}10^9\;CFU/kg$ diet) in an RAS for 8 weeks. Weight gain, the specific growth rate, feed efficiency, and protein efficiency ratio of the fish fed the CES diet in the RAS were 1.5~2.5 times higher than those of fish fed the basal diet alone, or the basal diet containing oxytetracycline (OTC), yeast plus bacterium, or Bacillus subtilis in a still water system. There was no significant difference in the pathogen challenge test between fish fed the OTC diet and fish fed the CES diet in the RAS, suggesting the CES-AQ1 probiotic used in the RAS as a potential replacement for antibiotics. The RAS biofilter maintained the highest microbial diversity and appeared to harbor microbial communities with ammonium oxidation, denitrification, and fish pathogen suppression functions. Ammonia, which is hazardous to fish, was significantly decreased to < 0.5 mg/L in 19 days, indicating the effectiveness of probiotic supplementation to maintain good water quality in RAS. These results suggest that the intestinal microbial communities of fish are stabilized by a probiotic-containing diet (CES) and that bioaugmentation with probiotics may be an eco-friendly and economical supplement for aquaculture of olive flounder, promoting both good water quality and fish health in an RAS.

• Korean Journal of Microbiology
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• v.30 no.1
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• pp.15-29
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• 1992

Vibrio vuln$cus has been recognized as a pathogen of septicemia and wound infection, when the organism attacks high-risk persons with a history of hepatic disease. alcohol abuse. diabetes or any debilitative disease. Forty six strains of K vulnzjicus. isolated from 1025 marine specimens from May to Novemver for three years. from 1985 to 1987. were studied for their biochemical properties. growth requirements, serotype and drug susceptibilities. The isolates were different in their various biochemical reactions. Ninety-five percent of isolated strains were able to ferment lactose, while most strains didn't utilize sucrose in their biochemical test, for example ornithine, gelatin and mannitol were quite dit'ferent composition than those described in other reports. It was found that the biochemical test wasn't useful for identifying strain. The type of somatic 0 antiserum was determined in isolates from marine sources and in patients with Vibrio septicemia. In patient isolates. 1-2 group were 24% and 1-4 group were 42%. However. 02 group(33%) were more abundant in isolates from marine sources. Minimal inhibitory concentrations(M1Cs) of chloramphenicol, tetracycline. erythromycin and ampicillin were determinef for V vuln~ficus by broth dilution method. MIC90 was I , 0.25, :! and 4,ug/ml in patient isolates. 1, 0.25, 2 and 2 ,ug/ml in marine isolates. The divalent chelating agent, IDTA. inhibited the growth of V. vuln!'ficus at 6.25 mMlml of MIC90.

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.66-72
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• 2024

Background: Vibrio vulnificus is a serious opportunistic human pathogen that has a worldwide distribution in a variety of marine and estuarine environments. Objectives: For this reason, we investigated the distribution of Vibrio vulnificus in coastal areas of Gyeonggido Province from 2018 to 2022. Also, we analyzed the correlation between V. vulnificus leading to infection and two marine environmental factors (water temperature and salinity). Methods: We collected a total of 266 samples from six coastal area points (i.e., seawater, mudflats). Specimens were isolated using selective plating media and isolated strains were identified by a VITEK 2 system. To find the relevance of the isolation rates of V. vulnificus and number of cases of V. vulnificus infection, we summarized the data on 48 cases of V. vulnificus infection from the open data of the Korea Disease Control and Prevention Agency. Results: Among the 266 samples taken during the investigation period, 47 strains were isolated, and the separation rates of V. vulnificus were 17.7%. The monthly isolation rates of V. vulnificus were ranked in the order of August (53.8%), September (33.3%), June (28.6%), and July (21.1%). There was a positive correlation with the temperature of seawater, but salinity was not significant. The number of cases of V. vulnificus infection reported in Gyeonggi-do Province were 18 (37.5%) in September, 14 (29.2%) in August, and eight (16.7%) in October. The proportion was 83.3%. It was relevant to the isolation rates of V. vulnificus in the marine environmental sources. Conclusions: Our data showed that the number of V. vulnificus infection cases could be affected by changes in the distribution of V. vulnificus due to rise the temperature of seawater in the marine environment.