• Journal of fish pathology
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• v.25 no.3
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• pp.249-256
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• 2012

Disease occurrence and dead cell ratio of Porphyra cultivated at Seocheon area were studied. Seaweed samples were collected monthly at 12 cultivating sites of Porphyra from Nov. 2008 to Mar. 2009. Although disease occurrence was low at the beginning of cultivation at the most of collecting sites, the occurrence increased with time. The most common symptom of Porphyra disease in this area was diatom attachment, followed by white rot disease. Licmophora sp. was the most common species of diatom and its attachment was the highest on November, the beginning of cultivation. Although the occurrence ratios of green spot disease and white rot disease were high on November, chytrid disease was increased at the end of cultivation period. Dead cell ratio of Porphyra thalli was different at each study site and cultivating time, but normally the ratio was high at the end of cultivating season. The changes of dead cell ratio could be related to the nutrition supplement and currents, and the more precise reason of dead cell ratio would be revealed by further research related to cultivating environment conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.5
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• pp.671-676
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• 2005

A total of 50 individual catfish, the Tra (Pangasius hypophthalmus) cultivated in either floating cages (Tra-c) or in ponds (Tra-p) and the Basa (Pangasius bocourti) raised in three floating cages, were collected in two of the Mekong Delta provinces. The caudal fin of each individual fish was used for protein electrophoresis employing the SDS-PAGE method. The one fillet sides were used as a representative sample to determine the dry matter (DM), crude protein (CP), ether extract (EE) and amino acids (AAs). The catfish oil was extracted from the belly fats, and the fatty acid (FA) composition was analyzed. There were 21 bands of the Tra and the Basa. Protein bands of the two varieties were 28.6-33.3% polymorphic, while polymorphic individuals of the Tra ranged from 80.0 to 100.0%, and the Basa was 90.0% polymorphic. The phenotypic diversity (Ho) of the Tra ranged from 1.71 to 1.80, while the Basa ranged as high as 2.14%. Diversity values (H$_{EP}$) for genetic diversity markers were equal in the Tra and the Basa. The sum of the effective number of alleles (SENA) of both varieties ranged from 3.40 to 3.83 for the Basa and the Tra, respectively. The lower values of Ho and SENA, as compared with those of the fresh water prawn (Macrobrachium equidens) in the area, would suggest that the species with the low values will become extinct due to inbreeding; the gene pools of each observed population were below a suitable threshold. Many of the differences in the nutritional values of the Tra-c, the Tra-p and the Basa were measured; their nutrient values were comparable to fishmeal or fish oil. Most of the DM, CP, and EE were higher in the Tra, especially in the Tra-c. The essential AA content, especially that of lysine, was highest in the Tra-c, next highest in the Tra-p, and lowest in the Basa. Therefore, the amino acid patterns were closer to the ideal patterns in the same sequences. In contrast, the essential FAs were concentrated in the Basa fish oil. It was found that suitable selection of parents for seed production is required to avoid inbreeding. Catfish may be valuable sources of nutrition for both humans and animals, and the differences in their nutritional values by variety and/or management must be taken into account.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.358-365
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• 2020

An organic solvent- and bleach-stable protease-producing strain was isolated from a polluted river water sample and identified as Aeromonas veronii OB3 on the basis of biochemical properties (API 20E) and 16S rRNA sequence analysis. The strain was found to hyper-produce alkaline protease when cultivated on fish waste powder-based medium (HVSP, 4080 U/ml). The biochemical properties and compatibility of OB3 with several detergents and additives were studied. Maximum activity was observed at pH 9.0 and 60℃. The crude protease displayed outstanding stability to the investigated surfactants and oxidants, such as Tween 80, Triton X-100, and H₂O₂, and almost 36% residual activity when incubated with 1% SDS. Remarkably, the enzyme demonstrated considerable compatibility with commercial detergents, retaining more than 100% of its activity with Ariel and Tide (1 h, 40℃). Moreover, washing performance of Tide significantly improved by the supplementation of small amounts of OB3 crude protease. These properties suggest the potential use of this alkaline protease as a bio-additive in the detergent industry and other biotechnological processes such as peptide synthesis.

• Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.40-48
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• 2022

Seahorses, which have been cultivated since the 2000s, are economically very important. Gas bubble disease (GBD) is a significant concern in the cultivation of seahorses; therefore, this study aimed to determine the cause of GBD-induced death in two species of Syngnathidae (Syngnathus schlegeli and Hippocampus haema). Rod-shaped bacteria were observed histopathologically and identified as Vibrio splendidus by conventional and real-time PCR analyses. The lethality of V. splendidus varies depending on the host's immune status, and the disease can be prevented through water quality management or improvement of the breeding environment. In this study, the GBD lesions (gas bubbles) were observed at 12℃, 8.0 mg/L of dissolved oxygen, 30 ppt of salinity, and pH 7.7. In addition, rod-shaped bacteria, infiltration of inflammatory cells, and extensive serous exudate were confirmed in the lesions where gas bubbles were found. PCR analysis was able to detect V. splendidus, possibly a secondary infection of the immunocompromised syngnathid fish. Understanding the risk of immunity control and the correlation between these lesions and causal agents will be of great help to the aquaculture industry and the ornamental fish market.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.91-99
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• 2016

The objective of this study was to investigate characteristics of inorganic components contained in liquid fertilizer produced using fish meal under different condition. Addition of dry yeast to liquid fertilizer resulted in considerable change in pH and electrical conductivity(EC) value compared to other liquid fertilizers which have microorganisms additives. In addition, it was appeared that the dry yeast-added treatment had higher $NH_4-N$ concentration than other treatments. Addition of molasses resulted in low pH compared to the control which has no additives. The EC, concentration $NH_4-N$ and $P_2O_5$ were not significant difference according to addition of molasses. The pH and $NH_4-N$ concentration in liquid fertilizer containing 20% of fish meal was highest after fermentation process, and EC value increased as the content of fish meal increase. When Cucumber was cultivated using liquid fertilizer, there was no difference in growth between fish meal liquid fertilizer treatment and chemical fertilizers treatment. However, there was a difference in yield according to the supply amount of nitrogen during the growing season.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1055-1064
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• 2006

Extremely slow growing anammox(anaerobic ammonium oxidation) bacteria were cultivated using a combination of UASB(Upflow Anaerobic Sludge Blanket) reactor seeded with anaerobic granular sludge and carbon-fiber cultivating reactor. After 180 days of continuous cultivation, average nitrogen removal rate showed 0.54 kg $N/m^3-day$ when 0.6 kg $N/m^3-day$ of nitrogen loading was applied. The black granule was changed to brown and red granule as continuous operation, and the red granule was highly dependant on the high anammox activity. Microbial community structure of red granule in the UASB reactor was analyzed by molecular methods such as gene cloning, phylogenetic tree analysis, and FISH(Fluorescence In Situ Hybridization) method. As a result of gene cloning and phylogenetic tree analysis, 5 kinds of phylum were found to be Planctomycetes, Proteobacteria, Acidobacteria, Chlorobi and Chloroflexi. 13 clones were matched to anammox bacteria among 51 clones in the red anammox granule. In-silico test which used cloning information and FISH probe of the AMX368 was conducted to detect the presence of anammox bacteria in the red anammox granule. As a result of in-silico test only one clone was exactly matched to AMX368 but 11 clones was mutated one base among 18 bases representing all 12 clones are anammox bacteria. A filamentous Chloroflexi might be related to the granulation of anammox bacteria. As a result of FISH analysis, anammox bacteria was abundant in the red anammox granule.

• Korean Journal of Microbiology
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• v.31 no.2
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• pp.113-122
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• 1993

Aeromonas veronii was isolated from the haemorrhagic ulcer of the snakehead that had been infected in natural condition, This bacterium was injected hypodermically into the healthy snakeheads and the effect was compared to the naturally infected fish. Both groups showed severe necrosis, falling off of epidermal tissue and hypodermal muscle. In both groups, severe histophathological changes were observed in gill, digestive tract and kidney just before death. Artificially injected fish showed necrosis of tissue in skin, gill and digestive tract from 2 days after injection. Then it showed necrosis or cell atrophy of tissue in kidney from 5 days after injection, and in liver and spleen just before death. Snakehead infected with haemorrhagic ulcer died within 9 days after infection, showing the symptom of skin damage and metabolic inhibition in respiration" digestion, excretion, etc. It was concluded that Aeromonas veronii (CA26) that was isolated from the naturally infected fish is the main bacterium causing haemorragic ulcer in the snakehead.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2001.08a
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• pp.34-35
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• 2001

RAPD analysis based on numerous markers have been used to investigate patterns of genetic differentiation ann and within two cultured and wild populations represented by the species crucian carp(Carassius carassius). From RAPD analysis using five primers, a total of 442 polymorphic bands were obtained in two populations and 273 were found to be specific to a wild population. According to RAPD-based estimates, average number of polymorphic bands in wild population was approximately 1.5 times as diverse as that in cultured. The average level of bandsharing values was $0.40 \pm 0.05$ in wild population, but was $0.69 \pm 0.08$ in cultured population, With reference to bandsharing values and banding patterns, wild population was considerably more diverse than cultured population. Knowledge of the genetic diversity of crucian carp should help in formulating more effective strategies for managing this aquacultural fish species.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.789-792
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• 2000

Marine chlorella (Nannochloropsis oculata) is cultivated at the fish farming association of experimental fishery laboratory. In the culture of the chlorella, it is necessary to count the number of chlorella in order to understand the condition of increase. For that purpose, we develop automatic chlorella counter using the image processing and the neural network. Its effectiveness is confirmed through the experiment.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.568-572
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• 2012

Determination of ploidy level for the mother plant is prerequisite for effective breeding. The study was carried out to determine the ploidy level in 7 different plant materials by FISH karyotype analysis. Among the seven plant varieties analyzed, all exhibit tetraploid (2n = 4x = 28) based on the results observed in chromosome analysis. Four signals of 45S rDNAs were detected on the terminal region of the short arm of chromosome 7. The length of somatic metaphase chromosomes ranges from 1.67 to $2.67{\mu}m$ in 'Alexandra', 1.40 to $2.04{\mu}m$ in 'Freud', 1.64 to 2.24 in 'Little Silver', 1.69 to $2.26{\mu}m$ in 'Teresa', 1.70 to $2.65{\mu}m$ in 'Tineke', 1.35 to $2.08{\mu}m$ in 'Vital', 1.39 to $2.04{\mu}m$ in 'Yellow Mimi'. Total length of the chromosome ranges from $11.23{\mu}m$ in 'Freud' as minimum to $15.05{\mu}m$ in 'Alexandra' as maximum. The karyotypes were composed of metacentric, submetacentric, and subtelocentric chromosome but there is no subtelocentric chromosome.