Isolation of a novel strain, Sphingorhabdus sp. YGSMI21 and characterization of its enantioselective epoxide hydrolase activity.

Sphingorhabdus sp. YGSMI21, a novel microbial strain with an enantioselective epoxide hydrolase activity, was isolated from tidal samples contaminated by accidental oil spills subjected to enriched culture with polycyclic aromatic hydrocarbon. This strain was able to optically decompose (R)-styrene oxide (SO) and showed 100% optical purity. In addition, it showed a good enantioselectivity for the derivatives of (S)-SO, (S)-2-chlorostyrene oxide (CSO), (S)-3-CSO and (S)-4-CSO. For (S)-2-CSO, (S)-3-CSO and (S)-4-CSO, 99.9%ee was obtained with the yield of 26.2%, 24.8%, and 11.0%, respectively, when using 10 mg cells of Sphingorhabdus sp. YGSMI21 at pH 8.0 with 4 mM racemic substrates at pH 8.0 and 25°C. The values obtained in this study for (S)-2-CSO, particularly the yield of 26.2%, is noteworthy, considering that obtaining an enantiomerically pure form is difficult. Taken together, Sphingorhabdus sp. YGSMI21 can be regarded as a whole-cell biocatalyst in the production of various (S)-CSO with the chlorine group at a different position.

Eisenia bicyclis (brown alga) modulates platelet function and inhibits thrombus formation via impaired P2Y12 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 αIIbß3 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 αIIbß3, 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.

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).

In Vitro Anticancer Activity of Phlorofucofuroeckol A via Upregulation of Activating Transcription Factor 3 against Human Colorectal Cancer Cells.

Phlorofucofuroeckol A (PFF-A), one of the phlorotannins found in brown algae, has been reported to exert anti-cancer property. However, the molecular mechanism for the anti-cancer effect of PFF-A has not been known. Activating transcription factor 3 (ATF3) has been reported to be associated with apoptosis in colorectal cancer. The present study was performed to investigate the molecular mechanism by which PFF-A stimulates ATF3 expression and apoptosis in human colorectal cancer cells. PFF-A decreased cell viability through apoptosis of human colorectal cancer cells. PFF-A increased ATF3 expression through regulating transcriptional activity. The responsible cis-element for ATF3 transcriptional activation by PFF-A was cAMP response element binding protein (CREB), located between positions -147 and -85 of the ATF3 promoter. Inhibition of p38, c-Jun N-terminal kinases (JNK), glycogen synthase kinase (GSK) 3ß, and IκB kinase (IKK)-α blocked PFF-A-mediated ATF3 expression. ATF3 knockdown by ATF3 siRNA attenuated the cleavage of poly (ADP-ribose) polymerase (PARP) by PFF-A, while ATF3 overexpression increased PFF-A-mediated cleaved PARP. These results suggest that PFF-A may exert anti-cancer property through inducing apoptosis via the ATF3-mediated pathway in human colorectal cancer cells.

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

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.

6,6'-Bieckol inhibits adipocyte differentiation through downregulation of adipogenesis and lipogenesis in 3T3-L1 cells.

BACKGROUND: Brown algae have been used for their nutritional value as well as a source of bioactive compounds with antioxidant, anti-inflammatory, antimicrobial and anti-obesity effects. Obesity is an important condition implicated in various diseases, including diabetes, hypertension, dyslipidemia and coronary heart disease. However, anti-obesity effects of Eisenia bicyclis remain unknown. RESULTS: We investigated the anti-obesity effects of 6,6'-bieckol, 6,8'-bieckol, 8,8'-bieckol, dieckol and phlorofucofuroeckol A isolated from E. bicyclis. Anti-obesity activity was evaluated by examining the inhibition of differentiation of 3T3-L1 adipocytes and the expression of peroxisome proliferator-activated receptor γ (PPARγ), CCATT/enhancer-binding protein α (C/EBPα) and sterol regulatory element binding protein-1c (SREBP-1c) at the mRNA and protein level. Differentiated 3T3-L1 cells were treated with the purified phlorotannins at concentrations of 10, 25 and 50 µg mL(-1) for 8 days. The results indicated that the purified phlorotannins suppressed the differentiation of 3T3-L1 adipocytes in a dose-dependent manner, without toxic effects. Among the five compounds, 6,6'-bieckol markedly decreased lipid accumulation and expression levels of PPARγ, C/EBPα, SREBP-1c (mRNA and protein), and fatty acid synthase and acyl-coA carboxylase (mRNA). CONCLUSION: These findings suggest that E. bicyclis suppressed differentiation of 3T3-L1 adipocyte through downregulation of adipogenesis and lipogenesis.

Hemeoxygenase 1 partly mediates the anti-inflammatory effect of dieckol in lipopolysaccharide stimulated murine macrophages.

Eisenia bicyclis is edible brown algae recognized as a rich source of bioactive derivatives mainly phlorotannins reported for their anti-oxidant properties. Of all phlorotannins identified so far, dieckol has shown the most potent effect in anti-inflammatory, radical scavenging and neuroprotective functions. However, whether dieckol up-regulates hemeoxygenase 1 (HO-1) and this mediates its anti-inflammatory effect in murine macrophages remains poorly understood. Dieckol (12.5-50 µM) inhibited nitric oxide production and attenuated inducible nitric oxide synthase, phospho (p)-PI-3K, p-Akt, p-IKK-α/ß, p-IκB-α and nuclear p-NF-κBp65 protein expressions, and NF-κB transcriptional activity in LPS (0.1 µg/ml) stimulated murine macrophages. On the other hand, dieckol up-regulated HO-1 which partly mediated its anti-inflammatory effect in murine macrophages. Thus, dieckol appeared to be a potential therapeutic agent against inflammation through HO-1 up-regulation.

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.

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.

Lactosucrose production by various microorganisms harboring levansucrase activity.

Production of the artificial sweetener, lactosucrose, by various microorganisms containing levansucrase activity was investigated. Of the tested bacteria, Bacillus subtilis was the most effective producer using lactose as an acceptor and sucrose as a fructosyl donor. Lactosucrose production by this strain was optimal at pH 6.0 and 55 degrees C whereupon 181 g lactosucrose l(-1) was produced from 225 g lactose l(-1) and 225 g sucrose l(-1) in 10 h.

Streptomycin-resistant (rpsL) or rifampicin-resistant (rpoB) mutation in Pseudomonas putida KH146-2 confers enhanced tolerance to organic chemicals.

We found that certain Str-, Gen- or Rif- mutants derived from Pseudomonas putida KH146-2, which are resistant to streptomycin, gentamicin or rifampicin, respectively, are tolerant to the aromatic compound 4-hydroxybenzoate (4HBA). The minimum inhibitory concentration (MIC) of 4HBA as the sole carbon source for the wild-type strain was 1%, whereas the MIC for the mutants was 1.7%. Frequency of 4HBA-tolerant mutants among spontaneous Str-, Gen- and Rif- mutants was 5-15%, 3-5%, and 3% respectively. These 4HBA-tolerant mutants also tolerated to a variety of organic chemicals such as 3-hydroxybenzoate, aliphatic and heterocyclic compounds, chlorobenzoates, as well as organic solvents toluene and m-xylene. The Str mutants had a point mutation in the rpsL gene, which produces the ribosomal protein S12. The Rif mutants were found to have a point mutation in the rpoB gene, which encodes the RNA polymerase beta-subunit. Mutation points in Gen mutants still remain unknown. Str-, Gen- and Rif-phenotypes occurred in spontaneous 4HBA-tolerant mutants which had been selected by successively increasing concentrations (from 0.8% to 5%) of 4HBA. Complementation experiments with one of the Str mutants demonstrated a causal relationship between a rpsL mutation (str-1) and 4HBA tolerance. Uptake experiments using [14C]-4HBA revealed that apparent ability of 4HBA to be taken up by the membrane transport system was reduced two to threefold in the mutants compared to the wild-type strain, accounting at least partly for the enhanced tolerance to 4HBA. Our approaches thus could be effective in improvement of tolerance to aromatic compounds of bacteria applicable for bioremediation.

Preparation of (1-->4)-beta-D-xylooligosaccharides from an acid hydrolysate of cotton-seed xylan: suitability of cotton-seed xylan as a starting material for the preparation of (1-->4)-beta-D-xylooligosaccharides.

Cotton-seed residual cake, which is a byproduct of the process of oil extraction from the seed, was delignified with sodium hypochlorite (1% available chlorine). Xylan was then prepared from the delignified wet material by alkali extraction with 15% sodium hydroxide. The cotton-seed xylan contained 64.7% xylose and 9.4% uronic acid. The xylan was hydrolyzed with 0.125 M sulfuric acid at 90 degrees C for 15 min. The resultant hydrolysis products were separated by gel-permeation chromatography on BioGel P-4 and Toyopearl HW-40F columns connected in series, with water as an eluate. Xylose and xylooligosaccharides with a degree of polymerization ranging from DP 2 to 15 were separated under such conditions, and each xylooligosaccharide-containing peak fraction afforded a single band on fluorophore-assisted carbohydrate electrophoresis. These results suggest that cotton-seed xylan is suitable for the preparation of xylose and xylooligosaccharides.