Publications by authors named "Chulhong Oh"

Green algae, particularly species, are rich in complex polysaccharides, such as ulvan, which have significant potential for biotechnological applications. However, the biochemical properties of ulvan depolymerised products remain underexplored. The enzymatic depolymerisation of ulvan has garnered attention owing to its cost advantages over alternative methods.

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In this study, we report the molecular and enzymatic characterisation of Spg103, a novel bifunctional β-glucanase from the marine bacterium sp. J103. Recombinant Spg103 (rSpg103) functioned optimally at 60 °C and pH 6.

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Agarases produce agar oligosaccharides with various structures exhibiting diverse physiological activities. α-Neoagaro-oligosaccharide hydrolase (α-NAOSH) specifically cleaves even-numbered neoagaro-oligosaccharides, producing 3,6-anhydro-l-galactose (l-AHG) and odd-numbered agaro-oligosaccharides (OAOSs). In this study, α-NAOSH from the agar-degrading marine bacterium JEA5 (Gaa117) was purified and characterized using an expression system to produce OAOSs and determine their bioactivity.

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The production of recombinant proteins in Escherichia coli is often challenged by cytoplasmic expression due to proteolytic degradation and inclusion body formation. Extracellular expression can overcome these problems by simplifying downstream processing and improving protein yields. This study aims to compare the efficiency of two Bacillus subtilis chitosanase signal peptides in mediating extracellular secretion in E.

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Bacterial extracellular vesicles (BEVs) are nanoscale membrane-bound structures involved in intercellular communication and transport of bioactive molecules. In this study, we described the proteomic insight and anti-inflammatory activity of Streptococcus parauberis BEVs (SpEVs). Proteomics analysis of SpEVs identified 6209 distinct peptides and 1039 proteins.

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Article Synopsis
  • * The team optimized conditions for extracting peptone from cutlassfish head muscle, achieving a nitrogen content indicative of effective breakdown and confirming its ability to support microbial growth comparable to and even better than commercial alternatives.
  • * Test results showed that peptone from cutlassfish heads led to significantly higher expression levels of specific proteins in E. coli, highlighting its potential for biotechnological applications while promoting sustainable waste management in the fish processing sector.
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  • Non-native species pose a significant threat to ecosystems, creating a need for effective decision support tools to identify those likely to become invasive.
  • The Weed Risk Assessment (WRA) has inspired the creation of Invasiveness Screening Kits (ISK), with the Terrestrial Plant Species Invasiveness Screening Kit (TPS-ISK) representing the latest advancements, offering more comprehensive and effective screening capabilities.
  • The TPS-ISK provides numerous benefits over the WRA, including improved protocol standards, comprehensive questionnaires, climate change considerations, and user-friendly design, allowing for reliable risk assessments of various plant species.
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Microalgae have gained attention as a promising source of chlorophylls and carotenoids in various industries. However, scaling up of conventional bubble columns presents challenges related to cell sedimentation and the presence of non-photosynthetic cells due to non-circulating zones and decreased light accessibility, respectively. Therefore, this study aimed to evaluate the newly developed continuously circulated bioreactor ROSEMAX at both laboratory and pilot scales, compared to a conventional bubble column.

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Low productivity and high cost remain major bottlenecks for the large-scale production of Haematococcus sp. This study explored biomass production and carotenoid accumulation in Haematococcus sp. (KCTC 12348BP) using drying film culture.

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Exosomes are a group of extracellular vesicles carrying membrane proteins, lipids, RNAs, and, cytosolic proteins, which play key role in intercellular communication and homeostasis. This study describes the isolation, physicochemical, morphological and molecular characterization, toxicity, wound healing, and regeneration properties of plasma derived exosomes from naive (phosphate-buffered saline [PBS]-injected; PBS-Exo) and Streptococcus parauberis-challenged (Sp-Exo) olive flounder (Paralichthys olivaceus). The average diameters of PBS-Exo and Sp-Exo were 120.

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Secretory phospholipase A (sPLA), which hydrolyzes the sn-2 acyl bond of lecithin in a Ca-dependent manner, is an important enzyme in the oil and oleochemical industries. However, most sPLAs are not stable under process conditions. Therefore, a thermostable sPLA was investigated in this study.

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This study aimed to characterise and evaluate the probiotic properties of a newly isolated marine bacterium, strain S6031. The isolated strain was identified as Pseudoalteromonas ruthenica. In vivo experiments were conducted with P.

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is a marine microalga that has been promoted worldwide as a super food. This study was conducted to evaluate its ability to improve memory in the older adults using 70% ethanol extract (SM70EE). This randomized, double-blind, placebo-controlled clinical trial comprised 80 volunteers recruited from Jeonbuk National University Hospital in Jeonju, Republic of Korea, who were randomly assigned to two groups.

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We recently identified a β-agarase, Gaa16B, in the marine bacterium JEA5. Gaa16B, belonging to the glycoside hydrolase 16 family of β-agarases, shows less than 70.9% amino acid similarity with previously characterized agarases.

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Article Synopsis
  • A marine bacterial strain (S1131) isolated from seawater was studied for its probiotic effects using zebrafish as a model system, showing high similarity to the existing strain Y2.
  • Zebrafish larvae pre-exposed to S1131 demonstrated significantly improved disease tolerance, with a survival rate of 73.3% after exposure to stressors, compared to 46.6% in a control group.
  • The strain exhibited immunomodulatory effects by reducing pro-inflammatory markers and increasing protective proteins like heat shock protein, suggesting its potential for applications in enhancing disease resistance.
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  • Xylanase-containing enzyme cocktails, particularly the xynS1 gene from Streptomyces sp. J103, are effective in hydrolyzing xylan for industrial applications.
  • The xynS1 gene encodes a protein that exhibits optimal activity at pH 5.0 and 55°C, with its activity significantly enhanced by certain metal ions.
  • When combined with acetyl xylan esterase (AXE) and commercial cellulase, the rXynS1 enzyme showed a 2.3-fold improvement in lignocellulosic biomass hydrolysis compared to using cellulase alone.
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Antioxidants prevent ageing and are usually quantified and screened using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. However, this assay cannot be used for salt-containing samples, such as the cell-free supernatants of marine microorganisms that are aggregated under these conditions. Herein, the DPPH solvent (methanol or ethanol) and its water content were optimized to enable the analysis of salt-containing samples, aggregation was observed for alcohol contents of >70%.

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sp. KIOST-1 (LK1) is a newly isolated cyanobacterium that shows no obvious cytotoxicity and contains high protein content for both human and animal diets. However, only limited information is available on its toxic effects.

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In this study, derived pectin nanoparticles (SmPNPs) were synthesized and multiple biological effects were investigated using in vitro and in vivo models. SmPNPs were not toxic to Raw 264.7 cells and zebrafish embryos up to 1 mg/mL and 200 µg/mL, respectively.

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Purified bioactive components of marine algae have shown great pharmaceutical and biomedical potential, including wound healing activity. However, the activity of Spirulina maxima is the least documented with regard to wound healing potential. In the present study, we investigated the regenerative and wound healing activities of a Spirulina (Arthrospira) maxima based pectin (SmP) using in vitro human dermal fibroblasts (HDFs) and in vivo zebrafish model.

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Transient receptor potential ankyrin 1 (TRPA1) is a cation channel that plays a critical role in the occurrence and transmission of pain. By screening 393 marine invertebrate extracts for their antagonistic activity against TRPA1, it was found that the extract of the edible sea cucumber had a remarkable potency. Bioassay-guided separation of the extract resulted in the isolation of six triterpene glycosides, including a novel analog.

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This study evaluated the modulation of gut microbiota, immune responses, and gut morphometry in C57BL/6 mice, upon oral administration of -derived modified pectin (SmP, 7.5 mg/mL) and pectin nanoparticles (SmPNPs; 7.5 mg/mL).

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Article Synopsis
  • This study shows that pectin from Spirulina maxima (SmP) boosts disease resistance in zebrafish, with higher survival rates against harmful bacteria compared to the control group.
  • Zebrafish larvae treated with SmP demonstrated significant increases in immune response genes, enhancing their defense mechanisms.
  • Overall, SmP appears to be a safe, natural option for improving immune responses and promoting disease resistance in aquaculture.
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Background: Acetyl xylan esterase plays an important role in the complete enzymatic hydrolysis of lignocellulosic materials. It hydrolyzes the ester linkages of acetic acid in xylan and supports and enhances the activity of xylanase. This study was conducted to identify and overexpress the acetyl xylan esterase (AXE) gene revealed by the genomic sequencing of the marine bacterium Ochrovirga pacifica.

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The agarase gene was identified from a draft genome sequence of JEA5, an agar-utilizing marine bacterium. Recently, three agarase-producing bacteria, , , and , in the genus were reported. However, there have been no reports of the molecular characteristics and biochemical properties of these agarases.

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