Nyun-Ho Park

Antioxidant Activity of Various Solvent Fractions from Edible Brown Alga, Eisenia bicyclis and Its Active Compounds

In this study, we aimed to elucidate the antioxidant capacity of Eisenia bicyclis and evaluated its antioxidant activity using various assay systems such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, reducing power ability, and content of total polyphenol. Among all the performed experiments, the ethyl acetate fraction of E. bicyclis exhibited higher antioxidant activities. From this finding, isolation and purification were performed on the ethyl acetate fraction and identified dieckol and phlorofucofureoeckol-A by spectroscopic analyses including FAB-mass in the negative mode, (1) H NMR, (13) C NMR, (1) H-(1) H COSY, HMQC, and HMBC spectra. Interestingly, ABTS radical scavenging activities of dieckol and phlorofucofuroeckol showed strong effects of 65.36% and 70.38% at a concentration of 50 μg/mL, respectively. DPPH radical scavenging and reducing power abilities were increased in a dose-dependent manner at various concentrations. These results suggest that dieckol and phlorofucofuroeckol-A of E. bicyclis may play an important role in protection from oxidative stress involving reactive oxygen species and may contribute to the development of new bio products, for example, a useful preservative to improve food quality and a drug for various oxidative damage-associated diseases. Practical Application: The results suggest that dieckol and phlorofucofuroeckol-A can be utilized as a natural source for potential application of antioxidant in food industry and drug for oxidative damage-associated diseases.

Diversity of Bacteria and Archaea in hypersaline sediment from Death Valley National Park, California

The objective of this study was to phylogenetically analyze microorganisms from the domains Bacteria and Archaea in hypersaline sediment from Death Valley National Park. Using domain‐specific primers, a region of the 16S rRNA gene was amplified using polymerase chain reaction (PCR), and the product was subsequently used to create a clone library. A total of 243 bacterial clones, 99 archaeal clones, and 209 bacterial isolates were examined. The 243 clones from Bacteria were affiliated with the following groups: the Bacilli (59 clones) and Clostridia (1) of the Firmicutes, Bacteroidetes (90), Proteobacteria (27), Cyanobacteria (18), Gemmatimonadetes (41), candidate division OP1 (5), Actinobacteria (1), and the Deinococcus‐Thermus division (1). Within the class Bacilli, 46 of 59 clones were tentatively identified as 10 unclassified species. The majority of bacterial isolates (130 of 209) were more closely related to the Bacillus subtilis–B. licheniformis clade than to any other recognized taxon, and an Ecotype Simulation analysis of B. subtilis relatives identified four previously unknown ecotypes. Several new genera were discovered within the Bacteroidetes (4) and the Gemmatimonadetes (2). Of the 99 archaeal clones, 94 were tentatively identified as belonging to 3 new genera within the Halobacteriaceae; other clones represented novel species within each of 4 established genera.

Antibiotic resistance of bacteria isolated from the internal organs of edible snow crabs.

Antibiotic resistance and microbiota within edible snow crabs are important for the Chionoecetes (snow crab) fishing industry. We investigated these parameters using culture methods and antibiotic susceptibility tests with six internal organs from three species of Chionoecetes. Each sample revealed many unexpected microbial species within Chionoecetes internal organs. On the basis of 16S rRNA sequence analysis of 381 isolates, the most abundant genera identified in Chionoecetes opilio were Acinetobacter spp. (24%), Bacillus spp. (4%), Pseudomonas spp. (34%), Stenotrophomonas spp. (28%), and Agreia spp. (11%). In Chionoecetes sp. crabs, Acinetobacter spp. (23%), Bacillus spp. (12%), and Psychrobacter spp. (20%) were most prevalent, while Agreia spp. (11%), Bacillus spp. (31%), Microbacterium spp. (10%), Rhodococcus spp. (12%), and Agrococcus spp. (6%) were most abundant in C. japonicus. Our antibiotic resistance test found resistance to all nine antibiotics tested in 19, 14, and two of the isolates from C. opilio, Chionoecetes sp., and, C. japonicus respectively. Our results are the first to show that microbes with antibiotic resistance are widely distributed throughout the internal organs of natural snow crabs.

Complete Genome Sequence of Halophilic Yeast Meyerozyma caribbica MG20W Isolated from Rhizosphere Soil

ABSTRACT Meyerozyma caribbica MG20W was originally isolated from rhizosphere soil on reclaimed land in the Republic of Korea. We describe herein the 10.64-Mbp-long genome sequence of M. caribbica MG20W, which exhibits high salt resistance.

Eisenia bicyclis (brown alga) modulates platelet function and inhibits thrombus formation via impaired P 2 Y 12 receptor signaling pathway

BACKGROUND AND PURPOSE Sea weeds have been used since ancient times in Asian countries, especially in Korea, Japan, and China, as both edible sea vegetables and traditional medicinal tonics due to their health benefits. Eisenia bicyclis has been studied for anti-allergic and anti-cancer effects; however, its effects on the cardiovascular system, especially on platelet function, are yet to be explored. Therefore, we examined the effect of E. bicyclis on platelet function. STUDY DESIGN AND METHODS E. bicyclis extract (EBE) was prepared and in vitro effects on ADP-induced platelet aggregation, granule secretion, intracellular calcium ion ([Ca2+]i) mobilization, fibrinogen binding to integrin αIIbβ3 and clot retraction were evaluated. Phosphorylation levels of MAPK signaling molecules and P2Y12 receptor downstream signaling pathway components were studied. In vivo effects were studied using an arteriovenous (AV) shunt model. RESULTS EBE markedly inhibited in vitro ADP-induced platelet aggregation, granule secretion (ATP release and P-selectin expression), [Ca2+]i mobilization, fibrinogen binding to integrin αIIbβ3, and clot retraction; attenuated MAPK pathway activation; and inhibited phosphorylation of PI3K/Akt, PLCγ2, and Src. The extract significantly inhibited in vivo thrombus weight in an AV shunt model. CONCLUSION E. bicyclis inhibits agonist-induced platelet activation and thrombus formation through modulation of the P2Y12 receptor downstream signaling pathway, suggesting its therapeutic potential in ethnomedicinal applications as an anti-platelet and anti-thrombotic compound to prevent cardiovascular diseases.

Complete Genome Sequence of Sphingorhabdus sp. YGSMI21, Exhibiting High Enantioselective Epoxide Hydrolase Activity

ABSTRACT Sphingorhabdus sp. YGSMI21 is a novel strain exhibiting high enantioselective hydrolysis activity for styrene oxide. Here, we present its complete genome sequence, consisting of one circular chromosome (3.86 Mb) and one plasmid (0.196 Mb).

Phylogeny of Marine Yeasts Isolated from Coastal Seawater in the East Sea of Korea

BACKGROUND:Yeasts are used in a variety of industries. However, most industries are biased towardSaccharomyces cerevisiae ; so we sought to explore non-conventional yeasts (NCY). This study aimed to isolate yeasts from seawater collected from the East Sea of Korea and to analyze the NCY. METHODS ANDRESULTS:We first collected seawater and performed pure isolation using four kinds of medium (GPY, DOB+CSM,DG18, and SCG). In total, 314 strains and 17 genera were isolated by ITS sequencing, including Aureobasidium pullulans (236 strains), Cryptococcus (19 strains), Cystobasidium (18 strains), and Rhodotorula (9 strains). Upon in-depth analysis, A. pullulans, the most dominant genus (236 strains), was divided into Group II (147 strains), Unknown I (8 strains), and Unknown II (49 strains). CONCLUSION: In this study, a total of 314 strains were isolated from seawater; many of these yeasts have been found and reported in seawater previously. In-depth analysis of A. pullulans, showed the dominance of Group I (21 strains) andGroup II (147 strains). We also discovered Unknown I (8 strains) and Unknown II (49 strains), which have not been reported previously.

Characterization of PAH (Polycyclic Aromatic Hydrocarbon)-Degrading Bacteria Isolated from Commercial Gasoline

Received: 27 July 2015 / Revised: 8 September 2015 / Accepted: 19 September 2015 Copyright c 2015 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.