Publications by authors named "Young-Baek Hur"

While Pacific oysters are important commercial aquaculture species worldwide, the effect of hormonal regulation and environmental conditions on growth and taste profile have not been fully known. Insulin-like growth factor (IGF) systems are known to play a major role in regulating neuroendocrine functions across various physiological processes and are particularly involved in growth. IGFs expression also is directly related to the nutritional status of vertebrates, however, full mechanism has not been clearly identified in bivalves.

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Environmental factors impact oyster growth, condition, and gonadal development, which is linked to gamete characteristics observed through histology. The reproductive cycle of bivalves is related to energy storage and utilization. Therefore, in this study, the year-round growth change and gonadal development of oysters were observed using histological analysis, and the biochemical composition changes were confirmed.

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Article Synopsis
  • Bacterial infections in aquaculture are a major problem, and antibiotic resistance is driving the need for alternative solutions.
  • A study compared juvenile olive flounders raised in biofloc versus seawater, exposing them to Streptococcus iniae to assess their susceptibility.
  • Results showed that flounders in seawater had higher susceptibility to S. iniae, with significant impacts on their survival rates and various blood parameters after infection.
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The purpose of this study was to confirm the limit of salinity tolerance in juvenile olive flounders (Paralichthys olivaceus) by changes in blood parameters, AChE, antioxidant and stress responses. The P. olivaceus (mean weight 38.

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Studies on the resistance of fish raised in bio-floc systems against bacterial infection are limited. We aimed to evaluate the changes in hematological parameters, antioxidant and immune responses, stress indicators, and acetylcholinesterase (AChE) in olive flounder, Paralichthys olivaceus, raised in bio-floc and seawater for 10 months and, then, infected with Edwardsiella tarda at concentrations of 0 (control), 6.61 × 10, 6.

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Article Synopsis
  • The study aimed to determine the best water temperature for breeding juvenile Paralichthys olivaceus in biofloc.
  • Findings showed that temperatures above 28 °C led to significant decreases in hemoglobin and hematocrit levels while increasing several plasma components like calcium and glucose.
  • Temperatures over 26 °C caused hematological changes and oxidative stress in the fish, suggesting that higher temperatures induce thermal stress.
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Antifreeze proteins (AFPs) are biological antifreezes with unique properties, including thermal hysteresis(TH),ice recrystallization inhibition(IRI),and interaction with membranes and/or membrane proteins. These properties have been utilized in the preservation of biological samples at low temperatures. Here, we review the structure and function of marine-derived AFPs, including moderately active fish AFPs and hyperactive polar AFPs.

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Most cold-adapted enzymes possess higher K and k values than those of their mesophilic counterparts to maximize the reaction rate. This characteristic is often ascribed to a high structural flexibility and improved dynamics in the active site. However, this may be less convincing to cold-adapted metabolic enzymes, which work at substrate concentrations near K.

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Ice-binding proteins (IBPs) can inhibit ice recrystallization (IR), a major cause of cell death during cryopreservation. IBPs are hypothesized to improve cell viability after cryopreservation by alleviating the cryoinjury caused by IR. In our previous studies, we showed that supplementation of the freezing medium with the recombinant IBP of the Arctic yeast Glaciozyma sp.

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In order to assess changes in the activity of immunecompetency present in Crassostrea gigas infected with Marteilioides chungmuensis (Protozoa), the total hemocyte counts (THC), hemocyte populations, hemocyte viability, and phagocytosis rate were measured in oysters using flow cytometry. THC were increased significantly in oysters infected with M. chungmuensis relative to the healthy appearing oysters (HAO) (P<0.

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A Gram-negative, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated MA1-1(T), was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain MA1-1(T) is phylogenetically closely related to Litoreibacter species and to Thalassobacter arenae. It exhibited 16S rRNA gene sequence similarities of 97.

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A Gram-negative, non-motile, rod-shaped bacterial strain, designated MA1-6T, was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea, and was characterized to determine its taxonomic position. Strain MA1-6T grew optimally at pH 7.0-8.

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The sea squirt Halocynthia roretzi is an important marine food resource species that is found in the waters around Korea. We describe the isolation and characterization of 13 new polymorphic microsatellite loci in 96 sea squirt samples that were collected from the marine environment of Samcheok on the east coast of Korea. The number of alleles that were observed for each locus ranged from six to 32, and the value of expected and observed heterozygosities was 0.

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Expresssed sequence tag (EST) analysis was developed from three cDNA libraries constructed from cells of the digestive tract, gonad, and liver of sea squirt. Randomly selected cDNA clones were partially sequenced to generate a total of 922 ESTs, in which 687 unique ESTs were identified respectively. Results of BLASTX search showed that 612 ESTs (89%) have homology to genes of known function whereas 75 ESTs (11%) were unidentified or novel.

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The mortality of sea squirts, Halocynthia roretzi, with softness syndrome threatens the sea squirt aquaculture industry in Asian countries. The molecular approach to understanding the pathogenesis of softness syndrome began with differential gene expression analysis of tissues from normal and dying organisms. In the present study, we show that the expression of Halocynthia roretzi metalloproteinase (HrMMP) was significantly upregulated in the tissues of dying organisms through screening of differentially expressed genes, reverse transcription-polymerase chain reaction (RT-PCR), and real-time PCR.

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