• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1672-1683
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• 2021

Vibrio parahaemolyticus is recognized as one of the most important foodborne pathogens responsible for gastroenteritis in humans. The bla_CARB-17 gene is an intrinsic β-lactamase gene and a novel species-specific genetic marker of V. parahaemolyticus. In this study, a loop-mediated isothermal amplification (LAMP) assay combined with a lateral flow dipstick (LFD) was developed targeting this bla_CARB-17 gene. The specificity of LAMP-LFD was ascertained by detecting V. parahaemolyticus ATCC 17802 and seven other non-V. parahaemolyticus strains. Finally, the practicability of LAMP-LFD was confirmed by detection with V. parahaemolyticus-contaminated samples and natural food samples. The results showed that the optimized reaction parameters of LAMP are as follows: 2.4 mmol/l Mg²⁺, 0.96 mmol/l dNTPs, 4.8 U Bst DNA polymerase, and an 8:1 ratio of inner primer to outer primer, at 63℃ for 40 min. The optimized reaction time of the LFD assay is 60 min. Cross-reactivity analysis with the seven non-V. parahaemolyticus strains showed that LAMP-LFD was exclusively specific for V. parahaemolyticus. The detection limit of LAMP-LFD for V. parahaemolyticus genomic DNA was 2.1 × 10^-4 ng/μl, corresponding to 630 fg/reaction and displaying a sensitivity that is 100-fold higher than that of conventional PCR. LAMP-LFD in a spiking study revealed a detection limit of approximately 6 CFU/ml, which was similar with conventional PCR. The developed LAMP-LFD specifically identified the 10 V. parahaemolyticus isolates from 30 seafood samples, suggesting that this LAMP-LFD may be a suitable diagnostic method for detecting V. parahaemolyticus in aquatic foods.

• Biomedical Science Letters
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• v.29 no.2
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• pp.81-87
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• 2023

Pan-Enterovirus (Pan-EV) infects millions of children and infants worldwide every year. As severe infections have recently been reported, the need for monitoring has consequently intensified. Pan-EV is a categorical name for waterborne enteroviruses belonging to the Picornaviridae family, and includes a wide range of pathogens including Coxsackievirus (CoxV), Echovirus (EcoV) and Enterovirus (EV). In this study, we proposed an optimal RT-nested PCR method for diagnosis of various types of Pan-EV in an aquatic environment and developed a positive control. Considering detection sensitivity, specific reaction, and final identification, one condition capable of amplifying 478 bp among the four candidates in the 1^st round PCR (RT-PCR) and one condition in the 2^nd round PCR (nested PCR) were selected. Through the detection of nucleic acids extracted from 123 groundwater samples and the detection sensitivity test based on artificial spiking in the sample, the methods are optimal for non-disinfected water samples such as groundwater. We developed a positive control for Pan-EV detection that can be amplified to different sizes under the two conditions. Accuracy could be further improved by testing for contamination from the control group. The method proposed in this study and the positive control developed are expected to be used in monitoring Pan-EV in aquatic environments including groundwater through future research using more samples.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.1
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• pp.41-52
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• 2024

Serotransferrin cDNA from the Siberian sturgeon Acipenser baerii was isolated and its expression patterns during early life intervals were characterized. It contained an ORF encoding a 708-aa-long polypeptide, including a 19-aa signal peptide. Bioinfomatic analysis and 3D modeling indicated a typical bi-lobal structure with conserved iron-coordinating residues. During embryonic development, the potential transition of maternally provisioned transcripts to zygotically de novo transcribed ones occurred around blastula stage. The transferrin mRNA levels peaked at stages responsible for pronephros, heart and erythropoietic component differentiation. After hatching, the transferrin mRNA expression gradually increased at early ontogenic phases (0 to 3 DPH) corresponding to the periods in which prolarvae exhibited increased blood circulation and liver differentiation. The expression decreased at subsequent stages in which prolarvae exhibited benthic movement. The tissue distribution assay indicated liver-predominant expression at fingerling stage. From the microinjection-based challenge with Aeromonas hydrophila at day-0 and day-7, the transcriptional response was modulated toward upregulation, in which the amounts induced at 6, 12 and 24 HPI were greater in prolarvae injected at day-7 than at day-0. Therefore, transferrin plays important roles in both early development and host protective responses to pathogens in the Siberian sturgeon.

• Journal of Microbiology and Biotechnology
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• v.34 no.6
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• pp.1276-1286
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• 2024

The environment has been identified as an origin, reservoir, and transmission route of antibiotic resistance genes (ARGs). Among diverse environments, freshwater environments have been recognized as pivotal in the transmission of ARGs between opportunistic pathogens and autochthonous bacteria such as Aeromonas spp. In this study, five environmental strains of Aeromonas spp. exhibiting multidrug resistance (MDR) were selected for whole-genome sequencing to ascertain their taxonomic assignment at the species-level and to delineate their ARG repertoires. Analyses of their genomes revealed the presence of one protein almost identical to AhQnr (A. hydrophila Qnr protein) and four novel proteins similar to AhQnr. To scrutinize the classification and taxonomic distribution of these proteins, all Aeromonas genomes deposited in the NCBI RefSeq genome database (1,222 genomes) were investigated. This revealed that these Aeromonas Qnr (AQnr) proteins are conserved intrinsic resistance determinants of the genus, exhibiting species-specific diversity. Additionally, structure prediction and analysis of contribution to quinolone resistance by AQnr proteins of the isolates, confirmed their functionality as quinolone resistance determinants. Given the origin of mobile qnr genes from aquatic bacteria and the crucial role of Aeromonas spp. in ARG dissemination in aquatic environments, a thorough understanding and strict surveillance of AQnr families prior to the clinical emergence are imperative. In this study, using comparative genome analyses and functional characterization of AQnr proteins in the genus Aeromonas, novel Aeromonas ARGs requiring surveillance has suggested.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.355-363
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• 2024

Although aquaculture shrimp production has increased, disease mortality has also increased. Acute hepatopancreatic necrosis disease (AHPND) is an emerging disease that significantly reduces production. In this study, we have investigated the potential of medicinal herbs in enhancing the immune system of shrimp. A mixture of medicinal herb extracts (Han In-jin, Artemisia iwayomogi kitamura and Cham Dang-gwi, Angelicae gigas Nakai) was absorbed into pellets and fed to whiteleg shrimp Litopenaeus vannamei for 12 weeks. The weight gain, immune activity, and disease resistance effects of the shirmp were examined. The growth performance of shrimp fed the mixture of medicinal herbal extracts was higher than that of the control group. The prophenoloxidase (proPO) activity was found to be significantly higher at 8 weeks in the 0.1% medicinal herb extract fed group. The cumulative mortality when artificially infected with AHPND pathogens commonly decreased in the 8 weeks fed group when compared with the control group. Furthermore, the RPS (relative percentage survival) was improved. This study confirmed that a mixture of medicinal herbal extracts has a positive effect on growth performance, innate immunity and disease resistance in shrimp. The optimum concentration of the medicinal herb extract for shrimp feed was 0.1% .

• Journal of fish pathology
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• v.26 no.2
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• pp.111-116
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• 2013

In this study, the disinfectant efficacy of Aqua farmsafe$^{(R)}$, composed of didecyldimethylammonium chloride (DDAC) and yucca extract was evaluated against Salmonella typhimurium and fish pathogens. Determination of the anti-microbial or anti-viral efficacy of the disinfectant was based on Animal, Plant and Fisheries Quarantine and Inspection Agency Regulation No. 2011-26, Korea. Anti-bacterial efficacy test by broth dilution method was used to determine the lowest effective dilution of the disinfectant following exposure to test bacteria for 30 min at $4^{\circ}C$. Aqua farmsafe and test bacteria or virus were diluted with distilled water (DW), standard hard water (SW) or organic matter dilution (OM) according to treatment condition. Under the our results, disinfectant efficacy of Aqua farmsafe$^{(R)}$ possesses 30~40 fold against fish pathogens including bacteria and virus compared to that on animal pathogenic bacteria, S. typhimurim. As the efficacy of Aqua farmsafe$^{(R)}$ against fish pathogen was investigated in vitro, a controlled field trial is required to determine whether the use of Aqua farmsafe$^{(R)}$ will be able to reduce fish diseases.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.67-72
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• 2004

Many port states such as New Zealand, the USA, Australia and Canada have strict regulations to prevent ships which arrive in their port from discharging polluted ballast water which contain harmful aquatic organism and pathogens. They are notified that transfer of polluted ballast water can cause serious injury to public health and damage to property and environment. For this reason, they perceived that the ballast exchange in deep sea is the most effective method, together with submitting the ballast management plan which contains the effective exchange method, ballast system and safety consideration. In this study, we pursued both nautical engineering analysis and optimization of algorithm in order to generate the sequence of stability and rapidity. Heuristic Algorithm was chosen on the basis of optimality and applicability to a sequential exchange problem. We have built an optimized algorithm, for automatic exchange of ballast water, by redefining core elements of the $A^\ast$ algorithm, such as node, operator and evaluation function. Final version of the optimized algorithm has been applied to existing bulk carrier and the performance of the algorithm has been verified successfully.

• Korean Journal of Veterinary Research
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• v.34 no.3
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• pp.627-633
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• 1994

A study on efficacy and safety of Bio-Gammamix was performed to use for the preventive drug against bacterial diseases to mirror carp(Cyprinus carpio), rainbow trout(Salmo gairdneri), eel(Anguilla japonica) and flounder(Paralichthys olivaceus). The main ingredients of Bio-Gammamix were ferrous fumarate and mixed extrated powders of licorice root, ox bile and garlic. The test drug was proved to improve feeding habit and feed efficiency and decrease cumulative mortality remarkably. After administration, no side effects and histopathological changes were observed. We can prevent outbreaks of bacterial diseases of fish by the dosage of 1kg/ton of fish body weight perorally once or two times in a day for 7 days and Bio-Gammamix is thought to be used effectively an widely against most bacterial fish pathogens.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.911-916
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• 2012

Recently, antibiotic resistant genes (ARGs) in the environment are emerging as pollutants, since these genetic contaminants can eventually be transferred to human pathogens. The aim of this study was to develop the experimental model of antibiotic resistant gene (ARG) plasmid transfer as a function of various environmental conditions. For this purpose, the multi drug resistant plasmid pB10, which is known to be originally isolated from a wastewater treatment plant, was selected as a model transfer plasmid and Escherichia coli $DH5{\alpha}$ containing pB10 was used as a model donor. Pseudomonas aeruginosa, an opportunistic pathogen, was selected as the recipient for the conjugation experiment. When the donor and recipient were exposed to various stressors including antibiotics and heavy metal as a function of the concentrations (10, 100 and, 1000 ppb), statistically increased plasmid transfer rate was observed at a concentration of 10 ppb of tetracycline and sulfamethoxazole compared to control (no antibiotic exposure). Accordingly, the developed experimental ARG model by various stressor is a promising tool for evaluating the dissemination of ARGs by micro-contaminants in aquatic environment.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.225-230
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• 2003

Many port states such as New Zealand, the USA, Australia and Canada have strict regulations to prevent ships which arrive in their port from discharging polluted ballast water which contain harmful aquatic organisms and pathogens. They are notified that transfer of polluted ballast water can cause serious injury to public health and damage to property and environment. For this reason, they perceived that the ballast exchange in deep sea is the most effective method, together with submitting the ballast management plan which contains the effective exchange method, ballast system and safety consideration. In this study, we make an effort to develop optimum ballast water exchange management and in result of that, it provide more convenient and stable process for preparing ballast water management plan.