Joong-Kyun Jeon

Purification and characterization of angiotensin I converting enzyme inhibitory peptides from the rotifer, Brachionus rotundiformis

Angiotensin I converting enzyme (ACE) inhibitory peptide was isolated from the marine rotifer, Brachionus rotundiformis. ACE inhibitory peptides were separated from rotifer hydrolysate prepared by Alcalase, alpha-chymotrypsin, Neutrase, papain, and trypsin. The Alcalase hydrolysate had the highest ACE inhibitory activity compared to the other hydrolysates. The IC(50) value of Alcalase hydrolysate for ACE inhibitory activity was 0.63 mg/ml. We attempted to isolate ACE inhibitory peptides from Alcalase prepared rotifer hydrolysate using gel filtration on a Sephadex G-25 column and high performance liquid chromatography on an ODS column. The IC(50) value of purified ACE inhibitory peptide was 9.64 microM, and Lineweaver-Burk plots suggest that the peptide purified from rotifer protein acts as a competitive inhibitor against ACE. Amino acid sequence of the peptide was identified as Asp-Asp-Thr-Gly-His-Asp-Phe-Glu-Asp-Thr-Gly-Glu-Ala-Met, with a molecular weight 1538 Da. The results of this study suggest that peptides derived from rotifers may be beneficial as anti-hypertension compounds in functional foods resource.

Analysis of immune gene expression modulated by benzo[a]pyrene in head kidney of olive flounder (Paralichthys olivaceus)

Poly aromatic hydrocarbons (PAHs) are known to cause functional disorder of fish immune responses. Alteration of inflammatory cytokines and other immune gene expressions by PAHs in immune organs may play a pivotal role in immunotoxicity. Thus this study aimed to elucidate the immunotoxic mechanism of PAH using benzo[a]pyrene (BaP) by analyzing the gene expression of cytokines (IL-1β, TNFα, IL-6, IL-8, IFNγ, Mx), apoptosis (FasL, SOD) and other immune related substances (Lysozyme, IgM) in head kidney and macrophage in olive flounder. In Q-PCR analysis, proinflammatory cytokine (IL-1β, IL-6, IL-8, TNFα) gene expressions were significantly upregulated by BaP while Mx and IgM gene expressions were significantly downregulated in head kidney by a longer exposure to BaP in vivo and in vitro. Lysozyme gene expression was initially upregulated but later downregulated in head kidney in vivo and in vitro. Inhibition test revealed that TNFα gene expression was upregulated by BaP via the AHR pathway as blocked by ANF while IL-6 and IFNγ gene expressions were upregulated by a calcium dependent pathway (i.e. NFAT) as blocked by EGTA. In primary macrophage cells, only IL-8 gene expression was significantly upregulated among proinflammatory cytokines while IFNγ, lysozyme and IgM gene expressions were downregulated by BaP. FasL and SOD expressions were not altered in head kidney cells but significantly upregulated in macrophage cells, indicating apoptosis and oxidative stress. These results indicate that exposure to BaP causes the downregulation of immune response by triggering the death of macrophage cells, the reduction of effectors like IgM and lysozyme, and the decrease of macrophage cell activity.

Characterization of Bioactive Peptides Obtained from Marine Invertebrates

Bioactive peptides as products of hydrolysis of diverse marine invertebrate (shellfish, crustacean, rotifer, etc.) proteins are the focus of current research. After much research on these muscles and by-products, some biologically active peptides were identified and applied to useful compounds for human utilization. This chapter reviews bioactive peptides from marine invertebrates in regarding to their bioactivities. Additionally, specific characteristics of antihypertensive, anti-Alzheimer, antioxidant, antimicrobial peptide enzymatic production, methods to evaluate bioactivity capacity, bioavailability, and safety concerns of peptides are reviewed.

Development of Functional Materials from Seafood By-products by Membrane Separation Technology

In recent years, functional foods and nutraceuticals have attracted much attention, particularly in regard to their impact on human health and prevention of certain diseases. Consequently, the production and properties of bioactive materials has received an increasing scientific interest over the past few years. Membrane processing offers several advantages over conventional methods for separation, fractionation, and recovery of those bioactive components. Membrane separation is a useful technique to extract, concentrate, separate, or fractionate the compounds. The use of membrane bioreactors to integrate a reaction vessel with a membrane separation unit is emerging as a beneficial method for producing bioactive materials such as peptides, chitooligosaccharides, and polyunsaturated fatty acids (PUFAs) from diverse seafood by-products. In this review, membrane applications of lipid-, carbohydrate-, and protein-based nutraceuticals and some minor bioactive components have been critically evaluated. This article discusses recent membrane technology related to the production of bioactive materials for health benefits from marine organisms and their processing by-products.

Comparison of Xenobiotic Metabolism and Antioxidative Status in Cultivated and Stocked Rockfish Sebastes schlegeli

우리나라의 총 어업 생산량은 최근 몇 년간은 대략 300만 톤 전후이며, 그 중에서 천해양식어업 생산량은 1,300,000 톤 정도여서 총 어업 생산량의 약 40%를 조금 넘고 있으며, 품종별로는 어류가 40% 이상을 차지하고 있다. 특히 조피볼락의 경우, 일반해면어업에서 어획되는 양은 지난 1990년 500,000 톤을 넘었던 것이 이후 줄어들어 1995년에는 1,700 톤에 불과하였으나 최근 들어 늘어나면서 2010년에는 2,400 톤이 되었다. 하지만 천해양식 품종으로 조피볼락의 양식생산량은 해를 더해감에 따라 늘어나고 있어 1995년의 985 톤에 비해 2010년에는 2만 톤을 상회함으로써 무려 28배가 넘는 신장세를 나타내었고, 생산량으로만 따지면 넙치류 다음으로 많은 양식어종이기도 하다(MOMAF, 2011). 한편, 우리나라에서는 1986년 이후 연안과 내수면에 수산생물종묘를 방류하여 수산자원의 증강을 도모하고 있고, 방류량은 참돔 등을 비롯하여 그 동안 58억 마리에 이르며, 특히 조피볼락은 볼락이나 황점볼락과 더불어 전 해역에 공통적으로 방류하는 어종이고, 조피볼락의 방류량은 2005년에 278만 마리, 2007년에 695만 마리로 어류에서는 넙치 다음으로 많이 방류하고 있다. 게다가 조피볼락의 자원조성 효과는 방류 전에 비해 어획량이 1.5-1.8배나 증가하였다는 보고가 있고(MOMAF, 2011), 양적으로 크게 증가한 것은 분명하지만 이들 방류어종의 질적인 평가는 아직 충분히 이루어지지 않고 있다고 여겨진다.산업의 급격한 발달에 따라 외인성 화학물질 등의 유독물질 유입이 해양으로 현저히 증가하였고 이에 따른 직접적 해양생물자원의 독성유발 및 독성물질 축적으로 인한 2차 피해가 증가하였다. 특히 과거 외국의 유류유출사고에서 발견된 결과 (Lee and Anderson, 2005) 를 고려하면, 외인성 화학물질을 통한 해양생물의 독성 피해는 적지 않은 것으로 추정된다. 외인성 화학물질에 오염되었을 경우 외인성 화학물질의 대사와 배설을 촉진하기 위하여 어류 간장이나 패류에서 이물질(xenobi-otics)의 대사에 관여하는 소화선의 약물대사 phase II 효소의 변화도 예상된다. 어류 및 패류에서 약물대사효계 phase I 효소의 하나인 mixed-function oxygenase (MFO) cytochrome P450은 polycyclic aromatic hydrocarbons (PAHs)의 대사에 관여하며 외부 화학물질에 오염시 활성유도가 관찰된다(Col-lodi et al., 1984; Gagnon and Holdway 1998; Peters et al., 1999). Phase II 대사효소계인 UDP-glucuronosyl transferase (UDPGT) 및 glutathione S-transferase (GST)는 endogenous