In vitro monoamine oxidase A and B inhibitory activity and molecular docking simulations of fucoxanthin

Fucoxanthin is the primary carotenoid found in edible seaweeds, such as Eisenia bicyclis, Undaria pinnatifida, and others. The aim of this study was to determine the effectiveness of fucoxanthin against Parkinson’s disease (PD) by inhibiting monoamine oxidase (MAO) A and B because MAO inhibitors are used in early management of PD. A sensitive enzyme-based chemiluminescent assay and kinetics methods were used to investigate the enzyme inhibitory activities and mode of inhibition. A molecular docking simulation was performed to clarify the binding characteristics of fucoxanthin to hMAO-A (2z5x) and hMAO-B (2v5z). Our results suggest that fucoxanthin shows significant inhibitory activity against hMAO-A and hMAO-B with IC₅₀ values of 197.41 ± 2.20 and 211.12 ± 1.17 μM, respectively. Selegiline was used as the positive control (IC₅₀: 10.54 ± 1.25 and 0.128 ± 0.01 μM for hMAO-A and hMAO-B, respectively). The enzyme-based kinetics results demonstrated that fucoxanthin inhibited both hMAOs in a reversible competitive manner. The molecular docking simulation predicted that fucoxanthin exhibits higher binding affinity towards hMAO-A and hMAO-B through hydrogen bonding and hydrophobic interactions. These findings suggest that fucoxanthin is a reversible competitive hMAO inhibitor that could be used to manage PD.     

Genotypic and phenotypic characterization of Phytophthora infestans in South Korea during 2009–2016 reveals clonal reproduction and absence of EU_13_A2 genotype

In order to better understand the Phytophthora infestans population structure in South Korea, 172 isolates were collected between 2009 and 2016 from four major potato cultivation areas. Fungicide (metalaxyl and dimethomorph) response, mating type, and microsatellite (SSR) genetic fingerprints were analysed to characterize these isolates. Ten isolates collected in Gyeongnam Province, which specializes in protected winter cultivation in polytunnels, were A2 mating type. All other isolates were A1 mating type. Overall, 42% of the isolates were resistant to metalaxyl, and 43% were sensitive. All isolates were sensitive to dimethomorph. From the SSR fingerprints, 45 distinct genotypes were identified, which could be clustered into four clonal lineages: KR_1_A1, KR_2_A2, SIB-1, and US-11. KR_1_A1 was the predominant P. infestans genotype in South Korea. KR_2_A2 was only found in Gyeongnam Province; all isolates were A2 mating type and resistant to metalaxyl. SIB-1 was dominant until 2013 but its frequency has gradually decreased in more recent years. US-11 was first found in 2014, after which its frequency has increased to become codominant with KR_1_A1. The calculated standardized index of association (I_A) suggests that the South Korean P. infestans population is undergoing clonal reproduction. When compared with populations of P. infestans from the Netherlands, it has less genetic diversity and the dominant Netherlands P. infestans genotype, EU_13_A2 (Blue_13), was not found in South Korea. Such monitoring of the pathogen population contributes to a more efficient integrated pest management-based control strategy for potato late blight control in South Korea.     

Effects of shift in growing season due to climate change on rice yield and crop water requirements

Paddy and Water Environment - According to recent climate projections for South Korea, increases in temperature and precipitation will affect water use and crop production associated with paddy...     

Polysaccharide from Codium fragile Induces Anti-Cancer Immunity by Activating Natural Killer Cells

Natural polysaccharides exhibit beneficial immune modulatory effects, including immune stimulatory and anti-cancer activities. In this study, we examined the effect of Codium fragile polysaccharide (CFP) on natural killer (NK) cell activation, and its effect on tumor-bearing mice. Intravenous CFP treatment of C57BL/6 mice resulted in the upregulation of CD69, which is a marker associated with NK cell activation. In addition, intracellular levels of interferon (IFN)-γ and the cytotoxic mediators perforin and granzyme B were markedly increased in response to the CFP treatment of splenic NK cells. IFN-γ production by NK cells was directly induced by CFP, whereas the upregulation of CD69 and cytotoxic mediators required IL-12. Finally, intraperitoneal treatment with CFP prevented CT-26 (murine carcinoma) tumor cell infiltration in the lungs, without significantly reducing the body weight. In addition, treatment with CFP prevented B16 melanoma cell infiltration in the lung of C57BL/6 mice. Moreover, the anti-tumor effect was diminished by the depletion of NK cells. Therefore, these data suggest that CFP may be used as an NK cell stimulator to produce a phenomenon that contributes to anti-cancer immunity.     

Bayesian Hierarchical Analysis for Multiple Health Endpoints in a Toxicity Study

Bayesian hierarchical models are built to fit multiple health endpoints from a dose-response study of a chemical contaminant, perchlorate. Perchlorate exposure results in iodine uptake inhibition in the thyroid, with health effects manifested by changes in blood hormone concentrations and histopathological effects on the thyroid. We propose empirical models to fit blood hormone concentration and thyroid histopathology data for rats exposed to perchlorate in the 90-day study of Springborn Laboratories Inc. (1998), based upon a mechanistic model derived from the assumed toxicological relationships between dose and the various endpoints. All of the models are fit in a Bayesian framework, and predictions about each endpoint in response to dose are simulated based on the posterior predictive distribution. A hierarchical model tries to exploit possible similarities between different combinations of sex and exposure duration, and it allows us to produce more stable estimates of dose-response curves. We also illustrate how the Bayesian model specification allows us to address additional questions that arise after the analysis.     

Reductive Dechlorination of Tetrachloroethylene by Green Rusts Modified with Copper

Reductive dechlorination of tetrachloroethylene (PCE) by green rust modified with copper (GR(Cu)) was investigated using a batch reactor system. Four different forms of GRs (GR-Cl, GR-SO₄, GR-CO₃, and GR-F) were synthesized by partial air oxidation of Fe(OH)₂ and used in reductive dechlorination. The addition of Cu(II) into GRs produced 100-nm particles on the surface of GRs, which were considered to be metallic Cu and transformed a portion of GR to magnetite. Concentration of Fe(II) in the liquid phase increased and concentration of Fe(II) in the solid phase decreased during the modification process and the extent of these changes was dependent on the amount of Cu(II) added. The most reactive of the modified GRs was GR-F(Cu), which reacted with PCE at a rate that was 80 times faster than that of GR-Cl(Cu). The rate of PCE degradation by GR-F(Cu) was strongly dependent on pH with higher rates at higher pH over the range of pH 7.5–11. Increasing concentrations of Cu(II) over the range of 0 to 5 mM increased rate constants. The rate of dechlorination of PCE by GR-F(Cu) showed surface saturation behavior with respect to PCE concentration.     

Comparison of neuroprotective effects of five major lipophilic diterpenoids from Danshen extract against experimentally induced transient cerebral ischemic damage

We observed neuroprotective effects of five major lipophilic diterpenes derived from Danshen (Radix Salvia miltiorrhiza) extract, such as cryptotanshinone (CTs), dihydrotanshinone I (DTsI), tanshinone I (TsI), tanshinone IIA (TsIIA) and tanshinone IIB (TsIIB), in the hippocampal CA1 region (CA1) against transient ischemic damage in gerbils. These diterpenes were administered 30 min before ischemia–reperfusion and the animals were sacrificed 4 days after ischemia–reperfusion. In the vehicle-treated-group, cresyl violet positive (CV⁺) cells and neuronal nuclei (NeuN)⁺ neurons were significantly decreased in the CA1. However, in the TsI- and CTs-treated-ischemia-groups, CV⁺ and NeuN⁺ neurons were abundant in the CA1. In the other groups, the number of CV⁺ and NeuN⁺ neurons was less than the TsI- and CTs-treated-ischemia-groups. In addition, gliosis induced by ischemic damage was apparently blocked in the TsI- and CTs-treated-ischemia-groups. These results suggest that TsI and CTs among five major lipophilic diterpenes have strong potentials for neuroprotection against ischemic damage.     

Changes in cyclooxygenase-2 immunoreactivity in the hippocampus in a model of streptozotocin-induced type 1 diabetic rats

In this study, we investigated diabetic stage dependent cyclooxygenase-2 (COX-2) immunoreactivity in the dentate gyrus in streptozotocin (STZ)-induced type 1 diabetic rats. The animals were sacrificed at 2, 3 and 4 weeks after STZ treatment. Blood glucose levels were increased after STZ treatment. COX-2 immunoreactivity in dentate gyrus was significantly increased in these regions 3 weeks after STZ treatment and restored to its basal level to 4 weeks after STZ treatment. In contrast, COX-2 immunoreactivity was not changed in CA3 region in all groups. These results suggest that STZ-induced type 1 diabetes transiently, but not permanently, decreased synaptic transmission and plasticity 3 weeks after STZ treatment in the dentate gyrus.     

Contrast-enhanced ultrasound analysis of renal perfusion in normal micropigs

Contrast-enhanced ultrasound is one of method for evaluating renal perfusion. The purpose of this project was to assess perfusion patterns and dynamics in normal micropig kidney using ultrasonographic contrast media. Eight young healthy micropigs were included in this study. Micropigs were anesthetized with propofol and received an intravenous bolus of microbubble contrast media through an ear vein. Time/mean pixel value (MPV) curves were generated for selected regions in the right renal cortex and medulla. The parenchyma was enhanced in two phases. The cortex was first enhanced followed by a more gradual enhancement of the medulla. A significant difference in perfusion was detected between the cortex and medulla. Following the bolus injection, the average upslope was 0.68 ± 0.27 MPV/sec, downslope was -0.27 ± 0.13 MPV/sec, baseline was 73.9 ± 16.5 MPV, peak was 84.6 ± 17.2 MPV, and time-to-peak (from injection) was 17.5 ± 6.6 sec for the cortex. For the medulla, the average upslope was 0.50 ± 0.24 MPV/sec, downslope was -0.12 ± 0.06 MPV/sec, baseline was 52.7 ± 7.0 MPV, peak was 65.2 ± 9.3 MPV, and time-to-peak (from injection) was 27.5 ± 5.0 sec. These data can be used as normal reference values for studying young micropigs.