Peroxiredoxin II is an essential antioxidant enzyme that prevents the oxidative inactivation of VEGF receptor-2 in vascular endothelial cells

Cellular antioxidant enzymes play crucial roles in aerobic organisms by eliminating detrimental oxidants and maintaining the intracellular redox homeostasis. Therefore, the function of antioxidant enzymes is inextricably linked to the redox-dependent activities of multiple proteins and signaling pathways. Here, we report that the VEGFR2 RTK has an oxidation-sensitive cysteine residue whose reduced state is preserved specifically by peroxiredoxin II (PrxII) in vascular endothelial cells. In the absence of PrxII, the cellular H(2)O(2) level is markedly increased and the VEGFR2 becomes inactive, no longer responding to VEGF stimulation. Such VEGFR2 inactivation is due to the formation of intramolecular disulfide linkage between Cys1199 and Cys1206 in the C-terminal tail. Interestingly, the PrxII-mediated VEGFR2 protection is achieved by association of two proteins in the caveolae. Furthermore, PrxII deficiency suppresses tumor angiogenesis in vivo. This study thus demonstrates a physiological function of PrxII as the residential antioxidant safeguard specific to the redox-sensitive VEGFR2.     

Immunostimulatory effect by aqueous extract of <Emphasis Type="Italic">Hizikia fusiforme</Emphasis> in RAW 264.7 macrophage and whole spleen cells

Hizikia fusiforme is a commonly used food that possesses potent anti-bacterial, anti-fungal, and anti-inflammatory activities. The immunostimulatory activities of aqueous extract of Hizikia fusiforme (HFAE) in RAW 264.7 macrophages and whole spleen cells were investigated. HFAE activated RAW 264.7 macrophages to produce cytokines such as nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in a dose-dependent manner. In addition, HFAE induced the mRNA expression of TNF-α, IL-1β, and IL-6 in RAW 264.7 macrophages. Moreover, HFAE stimulated proliferation of whole spleen cells and reference mitogen. Taken together, the results demonstrate that HFAE potently activates the immune function by regulating NO, TNF-α, IL-1β, and IL-6 in RAW 264.7 macrophage and promoting spleen cell proliferation.     

<Emphasis Type="Italic">Shewanella upenei</Emphasis> sp. nov., a lipolytic bacterium isolated from bensasi goatfish <Emphasis Type="Italic">Upeneus bensasi</Emphasis>

A Gram-staining-negative, motile, non-spore-forming and rod-shaped bacterial strain, 20-23R^T, was isolated from intestine of bensasi goatfish, Upeneus bensasi, and its taxonomic position was investigated by using a polyphasic study. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain 20-23R^T belonged to the genus Shewanella. Strain 20-23R^T exhibited 16S rRNA gene sequence similarity values of 99.5, 99.2, and 97.5% to Shewanella algae ATCC 51192^T, Shewanella haliotis DW01^T, and Shewanella chilikensis JC5^T, respectively. Strain 20-23R^T exhibited 93.1–96.0% 16S rRNA gene sequence similarity to the other Shewanella species. It also exhibited 98.3–98.4% gyrB sequence similarity to the type strains of S. algae and S. haliotis. Strain 20-23R^T contained simultaneously both menaquinones and ubiquinones; the predominant menaquinone was MK-7 and the predominant ubiquinones were Q-8 and Q-7. The fatty acid profiles of strain 20–23R^T, S. algae KCTC 22552^T and S. haliotis KCTC 12896^T were similar; major components were iso-C_15:0, C_16:0, C_16:1 ω7c and/or iso-C_15:0 2-OH and C_17:1 ω8c. The DNA G+C content of strain 20-23R^T was 53.9 mol%. Differential phenotypic properties and genetic distinctiveness of strain 20–23R^T, together with the phylogenetic distinctiveness, revealed that this strain is distinguishable from recognized Shewanella species. On the basis of the data presented, strain 20-23R^T represents a novel species of the genus Shewanella, for which the name Shewanella upenei sp. nov. is proposed. The type strain is 20–23R^T (=KCTC 22806^T =CCUG 58400^T).     

Microbial community analysis and identification of alternative host-specific fecal indicators in fecal and river water samples using pyrosequencing

It is important to know the comprehensive microbial communities of fecal pollution sources and receiving water bodies for microbial source tracking. Pyrosequencing targeting the V1-V3 hypervariable regions of the 16S rRNA gene was used to investigate the characteristics of bacterial and Bacteroidales communities in major fecal sources and river waters. Diversity analysis indicated that cow feces had the highest diversities in the bacterial and Bacteroidales group followed by the pig sample, with human feces having the lowest value. The Bacteroidales, one of the potential fecal indicators, totally dominated in the fecal samples accounting for 31%-52% of bacterial sequences, but much less (0.6%) in the river water. Clustering and Venn diagram analyses showed that the human sample had a greater similarity to the pig sample in the bacterial and Bacteroidales communities than to samples from other hosts. Traditional fecal indicators, i.e., Escherichia coli, were detected in the human and river water samples at very low rates and Clostridium perfringens and enterococci were not detected in any samples. Besides the Bacteroidales group, some microorganisms detected in the specific hosts, i.e., Parasutterella excrementihominis, Veillonella sp., Dialister invisus, Megamonas funiformis, and Ruminococcus lactaris for the human and Lactobacillus amylovorus and Atopostipes sp. for the pig, could be used as potential host-specific fecal indicators. These microorganisms could be used as multiple fecal indicators that are not dependent on the absence or presence of a single indicator. Monitoring for multiple indicators that are highly abundant and host-specific would greatly enhance the effectiveness of fecal pollution source tracking.     

Oil production from five marine microalgae for the production of biodiesel

Marine microalgae were studied as potential resources for the production of biodiesel. Five marine microalgae, Tetraselmis suecica, Phaeodactylum tricornutum, Chaetoceros calcitrans, Isochrysis galbana, and Nannochloropsis oculata were cultured in f/2 media, 12:12 L:D cycle at 20 ± 1°C with a light intensity of 36.3 μmol/m²/sec using a 15-L circular cylindrical photobioreactor. The dry cell weight, specific growth rate, biomass productivity, oil content and fatty acid composition of palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid of microalgae were determined. T. suecica, I. galbana, and N. oculata showed high dry cell weights of 0.58, 0.57, and 0.57 g/L, respectively. The culture period of T. suecica to reach the stationary phase was 9 days. On the other hand, N. oculata showed the longest culture period of 28 days to reach the stationary phase. T. suecica absorbed nitrate at the initial stages of cell growth, decreasing the nitrate concentration to 0.5 mg/L on day-7 of the culture. The highest oil contents were observed in P. tricornutum with a 25.31% dry cell weight and I. galbana with a 23.15% dry cell weight on day-9 after the stationary phase. I. galbana showed 417.33 mg of palmitic acid per g oil and T. suecica showed 235.61 mg of oleic acid per g oil. Stearic acid, linoleic acid, and linolenic acid did not exceed 30.02 mg/g oil in any of the microalgae. T. suecica showed the shortest culture period of 9 days to reach the stationary phase. Therefore, the highest biomass production of 0.58 g/L was obtained and I. galbana showed high biomass production of 0.57 g/ L and oil content of 23.15% of dry cell weight. Therefore, T. suecica and I. galbana can be selected as a potential candidate for the production of biodiesel.     

Decarbonylated cyclophilin A Cpr1 protein protects <Emphasis Type="BoldItalic">Saccharomyces cerevisiae</Emphasis> KNU5377Y when exposed to stress induced by menadione

Cyclophilins are conserved cis–trans peptidyl-prolyl isomerase that are implicated in protein folding and function as molecular chaperones. The accumulation of Cpr1 protein to menadione in Saccharomyces cerevisiae KNU5377Y suggests a possibility that this protein may participate in the mechanism of stress tolerance. Stress response of S. cerevisiae KNU5377Y cpr1Δ mutant strain was investigated in the presence of menadione (MD). The growth ability of the strain was confirmed in an oxidant-supplemented medium, and a relationship was established between diminishing levels of cell rescue enzymes and MD sensitivity. The results demonstrate the significant effect of CPR1 disruption in the cellular growth rate, cell viability and morphology, and redox state in the presence of MD and suggest the possible role of Cpr1p in acquiring sensitivity to MD and its physiological role in cellular stress tolerance. The in vivo importance of Cpr1p for antioxidant-mediated reactive oxygen species (ROS) neutralization and chaperone-mediated protein folding was confirmed by analyzing the expression changes of a variety of cell rescue proteins in a CPR1-disrupted strain. The cpr1Δ to the exogenous MD showed reduced expression level of antioxidant enzymes, molecular chaperones, and metabolic enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH)- or adenosine triphosphate (ATP)-generating systems. More importantly, it was shown that cpr1Δ mutant caused imbalance in the cellular redox homeostasis and increased ROS levels in the cytosol as well as mitochondria and elevated iron concentrations. As a result of excess ROS production, the cpr1Δ mutant provoked an increase in oxidative damage and a reduction in antioxidant activity and free radical scavenger ability. However, there was no difference in the stress responses between the wild-type and the cpr1Δ mutant strains derived from S. cerevisiae BY4741 as a control strain under the same stress. Unlike BY4741, KNU5377Y Cpr1 protein was decarbonylated during MD stress. Decarbonylation of Cpr1 protein in KNU5377Y strain seems to be caused by a rapid and efficient gene expression program via stress response factors Hsf1, Yap1, and Msn2. Hence, the decarbonylated Cpr1 protein may be critical in cellular redox homeostasis and may be a potential chaperone to menadione.     

Influence of performance level on anaerobic power and body composition in elite male judoists

This study examined the relationship between 30-second anaerobic power and body composition by performance level in elite Judoists. During a 3-month period, 10 male Korean Judo national team athletes (NT), 26 male university varsity team athletes (VT), and 28 male junior varsity team athletes (JT) were assessed for 30-second anaerobic power and body composition at the Youngin University. Anaerobic power was measured using a 30-second Wingate test. Body composition was assessed via bioelectric impedance analysis in standardized conditions using BioSpace (Korean)-specific prediction formulas. All testing occurred at the beginning of the winter nonseason period but excluded a brief weight-loss period before the competition phase. Anaerobic power measures were significantly greater (p < 0.05) in NT and VT than in JT. Fat-free mass (FFM), muscle mass (MM), and total body water in JT were also greater than in VT and JT (p < 0.05). Muscle mass in VT was significantly lower than in NT (p < 0.05). Fat-free mass in NT was strongly correlated to mean and peak anaerobic power (r = 0.77, p = 0.009; r = 0.87, p < 0.001, respectively). Varsity team athletes also indicated a moderate association between FFM and peak and mean anaerobic power (r = 0.63, p < 0.001; r = 0.48, p = 0.013, respectively). However, relationship between FFM and anaerobic power was not statistically significantly correlated in JT (r = 0.14, p = 0.470; r = 0.23, p = 0.232, separately). In conclusion, our data indicated that anaerobic power is closely correlated with increase in FFM and MM and was different dependent among performance levels. Further research in the field is warranted to elucidate the Judo-specific relationship between FFM and performance.     

Mixotrophy in the newly described phototrophic dinoflagellate Woloszynskia cincta from western Korean waters: feeding mechanism, prey species and effect of prey concentration

Woloszynskia species are dinoflagellates in the order Suessiales inhabiting marine or freshwater environments; their ecophysiology has not been well investigated, in particular, their trophic modes have yet to be elucidated. Previous studies have reported that all Woloszynskia species are photosynthetic, although their mixotrophic abilities have not been explored. We isolated a dinoflagellate from coastal waters in western Korea and established clonal cultures of this dinoflagellate. On the basis of morphology and analyses of the small/large subunit rRNA gene (GenBank accession number=FR690459), we identified this dinoflagellate as Woloszynskia cincta. We further established that this dinoflagellate is a mixotrophic species. We found that W. cincta fed on algal prey using a peduncle. Among the diverse prey provided, W. cincta ingested those algal species that had equivalent spherical diameters (ESDs) ≤12.6 μm, exceptions being the diatom Skeletonema costatum and the dinoflagellate Prorocentrum minimum. However, W. cincta did not feed on larger algal species that had ESDs≥15 μm. The specific growth rates for W. cincta increased continuously with increasing mean prey concentration before saturating at a concentration of ca. 134 ng C/ml (1,340 cells/ml) when Heterosigma akashiwo was used as food. The maximum specific growth rate (i.e. mixotrophic growth) of W. cincta feeding on H. akashiwo was 0.499 d(-1) at 20 °C under illumination of 20 μE/m(2) /s on a 14:10 h light-dark cycle, whereas its growth rate (i.e. phototrophic growth) under the same light conditions without added prey was 0.040 d(-1). The maximum ingestion and clearance rates of W. cincta feeding on H. akashiwo were 0.49 ng C/grazer/d (4.9 cells/grazer/d) and 1.9 μl/grazer/h, respectively. The calculated grazing coefficients for W. cincta on co-occurring H. akashiwo were up to 1.1 d(-1). The results of the present study suggest that grazing by W. cincta can have a potentially considerable impact on prey algal populations.