• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.3
• /
• pp.403-416
• /
• 2020

The purpose of this study was to evaluate the food functional properties and in vitro bioactivity of vacuum freeze-dried fish roe concentrates (FRCs) prepared from Alaska pollock Theragra chalcogramma (AP), bastard halibut Paralichthys olivaceus (BH) and skipjack tuna Katsuwonus pelamis (ST). All three species showed better buffering capacity on the alkaline side (pH 10-12) than on the acidic side. The water-holding capacities of the FRCs were 3.5, 8.5 and 4.2 g/g protein for AP, BH and ST, respectively, and were significantly higher than that of commercial egg white. The protein solubilities of the FRCs were 42.5% (AP), 50.0% (BH) and 13.9% (ST). The foaming capacities of the FRCs were not significantly different among the species (128.0% for AP, 128.3% for BH, and 143.3% for ST; P>0.05), and their foam stability was maintained at 53.0-74.2% for 60 minutes. The oil-in-water emulsifying activity indexes of AP and BH (19.5 and 20.2 ㎡/g protein, respectively) were significantly superior to that of ST (P<0.05). The 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothia-zoline-6-sulfonic acid radical-scavenging activities (IC₅₀, mg/mL) of the FRCs were in the ranges of 1.05-3.26 and 0.13-0.18 mg/mL, respectively, and the angiotensin I converting enzyme inhibitory activity was in the range of 0.97-1.89 mg/mL.

• Journal of Biomedical and Translational Research
• /
• v.19 no.4
• /
• pp.130-139
• /
• 2018

This study aimed to analyze a high-performance liquid chromatography (HPLC) separation using a pentafluorophenyl column of parent drug hydroxychloroquine (HCQ) and its active metabolite, desethylhydroxchloroquine (DHCQ) applying to determine bioequivalence of two different formulations administered to patients. A rapid, simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for bioanalysis of HCQ and its metabolite DHCQ in human whole blood using deuterium derivative $hydroxychloroquine-D_4$ as an internal standard (IS). A triple-quadrupole mass spectrometer was operated using electrospray ionization in multiple reaction monitoring (MRM) mode. Sample preparation involves a two-step precipitation of protein techniques. The removed protein blood samples were chromatographed on a pentafluorophenyl (PFP) column ($50mm{\times}4.6mm$, $2.6{\mu}m$) with a mobile phase (ammonium formate solution containing dilute formic acid) in an isocratic mode at a flow rate of 0.45 mL/min. The standard curves were found to be linear in the range of 2 - 500 ng/mL for HCQ; 2 - 2,000 ng/mL for DHCQ in spite of lacking a highly sensitive MS spectrometry system. Results of intra- and inter-day precision and accuracy were within acceptable limits. A run time of 2.2 min for HCQ and 2.03 min for DHCQ in blood sample facilitated the analysis of more than 300 human whole blood samples per day. Taken together, we concluded that the assay developed herein represents a highly qualified technology for the quantification of HCQ in human whole blood for a parallel design bioequivalence study in a healthy male.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.51 no.6
• /
• pp.623-631
• /
• 2018

The present study investigated the food component characteristics of a bone-softened mackerel Scomber japonicus product (FC-M). The proximate composition of the FC-M was 57.4% moisture, 25.2% crude protein, 14.1% crude lipid, and 2.7% ash. The energy in the FC-M was 241.5 kcal/100 g, which corresponds to 8.9-16.1% of the daily energy intake recommended for Koreans ${\geq}6$ years of age. Regardless of type of taste, there were no significant differences in taste intensity when the FC-M was compared to a control (canned mackerel) but the odor intensity was significantly higher. Although there were no significant differences in hardness, the Hunter color values of redness and yellowness were significantly lower than those of the control. The sensory score for the FC-M was significantly superior to that of the control. The total amino acid content in the FC-M was 24.12 g/100 g and the major amino acids were aspartic acid, glutamic acid, leucine, and histidine. The major fatty acids in the FC-M were 16:0, 18:1n-9, 20:5n-3, and 22:6n-3 and the FC-M was a good source of minerals.

• Journal of fish pathology
• /
• v.23 no.1
• /
• pp.37-45
• /
• 2010

In this study, we carried out research on the level of single and multi-drug resistance of bacteria isolated from cultured flounder Paralichthys olivaceus. One hundred sixty one bacteria were isolated from cultured olive flounder Paralichthys olivaceus in Korea and the isolates consisted of Edwardsiella tarda (n=32), Vibrio ichthyoenteri (n=37), Vibrio spp. (n=54), Streptococcus parauberis (n=28) and Streptococcus spp. (n=10). These E. tarda isolates were highly resistant in the order of tetracycline (84.4%) and oxolinic acid (71.9%). V. ichthyoenteri and Vibrio spp. showed resistance ampicillin (94.6% and 81.5%) and tetracycline (56.8% and 42.6%). S. parauberis isolates were resistant ampicillin (57.1%), tetracycline (57.1%) and erythromycin (35.7%). Of the isolates, 84.4% of E. tarda, 73.0% of V. ichthyoenteri, 57.4% of Vibrio spp., 42.8% of S. parauberis and 70.0% of Streptococcus spp. isolates exhibited multi-drug resistance against more than two antibiotics.

• Korean Journal of Food Science and Technology
• /
• v.43 no.2
• /
• pp.125-133
• /
• 2011

The purpose of this study was to develop a methodology to detect spinosad which are difficult to analyze by multi-component simultaneous analysis of pesticide residues. We monitored spinosad due to the paucity of related information. The spinosad was determined using HPLC with UV detector at 250 nm. Correlation coefficient ($r^2$) for standard curve of spinosad A and D at standard concentration of 0.1-5.0 mg/kg were 0.999, respectively. Limit of quantitation (LOQ) of HPLC analysis was 0.005 mg/kg while limit of detection (LOD) was 0.001 mg/kg. Recovery experiments were conducted on five representative agricultural products to validate the analytical method. The recovery of proposed methods ranged from 74.9% to 104.0% and relative standard deviations were less than 10%. Spinosad residues were investigated in 16 commodities collected from 22 provinces. In this study, residues on all samples were not detected.

• Journal of Fisheries and Marine Sciences Education
• /
• v.26 no.6
• /
• pp.1278-1295
• /
• 2014

The Sixteenth Meeting of the Conferences of Parties of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which was held in March 2013 in Bangkok, Thailand, listed five shark species and one genus, and uplisted one sawfish species. All new species listings will be come into force of the eighteen months delay, on the fourteenth of September, 2014. The purpose of the delay is to support the preparation of the domestic measures on shark trade by the parties, as there has been no previous experience in trading the commercially exploited aquatic species in the CITES. The CITES Secretary-General has visited several potential shark trade countries to encourage and facilitate the implementation of the new CITES listings. The newly listed sharks have been caught as a target or non-target species by Korean distant water fisheries and introduced into Korea. So the establishment or change of the domestic laws, regulations, and measures for the implementation of the new CITES species must be prepared before the effective entry date. This paper is prepared to assess the effects of the trade of the CITES listed shark species, and to suggest effective government service measures for the management of Korean distant water fisheries. The Ministry of Environment (MOE) is the general Management Authority of the CITES, and the Ministry of Food and Drug Safety (MFDS) is in charge of the medical trade of CITES listed species in Korea. By law, all imported medicines and medical materials must be inspected by the MFDS during the customs examination; this kind of authority sharing is reasonable and effective way of providing government service. Similarly, the designation of new CITES Management Authority for the trade of commercially exploited aquatic CITES species is critical and the Ministry of Oceans and Fisheries (MOF), which is now in charge of the trade of fisheries products, is the most appropriate governing body for this purpose in Korea. The revision of the National Plan of Action for Conservation and Management of Sharks, initially submitted to the Food and Agriculture Organization (FAO) of the United Nations in 2011 as a practical guideline for shark conservation in all Korean fisheries, could be a effective measure to achieve unification of conservation of endangered species and sustainable use of fisheries stocks. The proper CITES measures for the trade of listed species, such as the establishment of the documenting system for Non-detriment Findings, domestic measures suitable for the "Introduction from the Sea" clause, species specific Harmonized System Codes for the customs service, and an effective shark catch data reporting system should be in place prior to the fourteenth of September 2014.

• Fisheries and Aquatic Sciences
• /
• v.17 no.2
• /
• pp.209-214
• /
• 2014

With the continuing demand for new solutions in the development of effective and safe candidiasis therapies, we investigated the efficacy of an antifungal agent from the marine brown alga Eisenia bicyclis. The methanolic extract of E. bicyclis evinced potential antifungal activity against Candida species. The ethyl acetate (EtOAc)-soluble extract from E. bicyclis demonstrated the strongest antifungal activity against Candida species among five solvent-soluble extracts. Indeed, the EtOAc-soluble extract showed minimum inhibitory concentrations (MICs) ranging from 4 to 8 mg/mL. Furthermore, the EtOAc-soluble extract considerably reversed high-level fluconazole resistance of Candida species. The MIC values of fluconazole against Candida species decreased substantially (from 64 to $4{\mu}g/mL$) in combination with the MIC of the EtOAc-soluble extract (4 mg/mL). The fractional inhibitory concentration indices of fluconazole ranged from 0.531 to 0.625 in combination with 4, 2, or 1 mg/mL of the EtOAc-soluble extract against Candida isolates, indicating that these combinations exert a marked synergistic effect against Candida isolates. These findings imply that compounds derived from E. bicyclis can be a potential source of natural antifungal agents against Candida species.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.8
• /
• pp.1441-1448
• /
• 2017

Antibacterial compounds are widely used in the treatment of human and animal diseases. The overuse of antibiotics has led to a rapid rise in the prevalence of drug-resistant bacteria, making the development of new antibacterial compounds essential. This study focused on developing a fast and easy method for identifying marine bacteria that produce antibiotic compounds. Eight randomly selected marine target bacterial species (Agrococcus terreus, Bacillus algicola, Mesoflavibacter zeaxanthinifaciens, Pseudoalteromonas flavipulchra, P. peptidolytica, P. piscicida, P. rubra, and Zunongwangia atlantica) were tested for production of antibacterial compounds against four strains of test bacteria (B. cereus, B. subtilis, Halomonas smyrnensis, and Vibrio alginolyticus). Colony picking was used as the primary screening method. Clear zones were observed around colonies of P. flavipulchra, P. peptidolytica, P. piscicida, and P. rubra tested against B. cereus, B. subtilis, and H. smyrnensis. The efficiency of colony scraping and broth culture methods for antimicrobial compound extraction was also compared using a disk diffusion assay. P. peptidolytica, P. piscicida, and P. rubra showed antagonistic activity against H. smyrnensis, B. cereus, and B. subtilis, respectively, only in the colony scraping method. Our results show that colony picking and colony scraping are effective, quick, and easy methods of screening for antibacterial compound-producing bacteria.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.12
• /
• pp.2303-2309
• /
• 2007

Expressed protein ligation (EPL) technique, joining recombinantly expressed proteins to polypeptides, has been widely adopted for addressing various biological questions and for drug discovery. However, joining two recombinant proteins together is sometimes difficult when proteins are expressed insoluble and unrefoldable, because ligation-active proteins via intein-fusion are obtainable when they are folded correctly. We overcame this limitation coexpressing target protein with additional methionine aminopeptidase (MAP) which enhances removal of the initiation methionine of recombinantly expressed protein. Our approach demonstrated that two domains of 46 kDa 5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase, a target of herbicide glyphosate, were successfully joined by native chemical ligation, although its C-terminal domain was expressed as an inclusion body. The intein-fused N-terminal fragment of EPSP synthase (EPSPSN, residues 1-237) was expressed and the ligation-active thioester tagged N-terminal fragment (EPSPSN-thioester) was purified using a chitin affinity chromatography and mercapto-ethanesulphonate (MESNA) as intein thiolysis reagent. Its Cterminal fragment (EPSPSC, residues Met237-238CYS-427), expressed as an inclusion body, was prepared from an additional MAP-expressing strain. Protein ligation was initiated by mixing ~1 mM of EPSPSN-thioester with ~2 mM of EPSPSCCYS (residues 238CYS-427). Also we found that addition of 2% thiophenol increased the ligation efficiency via thiol exchange. The ligation efficiency was ~85%. The ligated full-length EPSP synthase was dissolved in 6 M GdHCl and refolded. Circular dichroism (CD) and enzyme activity assay of the purified protein showed that the ligated enzyme has distinct secondary structure and ~115% specific activity compared to those of wild-type EPSP synthase. This work demonstrates rare example of EPL between two recombinantly expressed proteins and also provides hands-on protein engineering protocol for large proteins.

• Food Science and Biotechnology
• /
• v.15 no.5
• /
• pp.664-671
• /
• 2006

Modeling the growth kinetics of lactic acid bacteria (LAB), one of the most valuable microbial groups in the food industry, has been actively pursued in order to understand, control, and optimize the relevant fermentation processes. Most modeling approaches have focused on the development of single population models. Primary single population models provide fundamental kinetic information on the proliferation of a primary LAB species, the effects of biological factors on cell inhibition, and the metabolic reactions associated with cell growth. Secondary single population models can evaluate the dependence of primary model parameters, such as the maximum specific growth rate of LAB, on the initial external environmental conditions. This review elucidates some of the most important single population models that are conveniently applicable to the LAB fermentation analyses. Also, a well-defined mixed population model is presented as a valuable tool for assessing potential microbial interactions during fermentation with multiple LAB species.