Proliferation of kuchijirosho causative agent in a fugu-derived cell line

Kuchijirosho is a fatal disease of commercially cultured fugu, Takifugu rubripes. The transmissible nature of kuchijirosho strongly suggests that an infectious pathogen is the causative agent. Because it is filtrable, the agent is thought to be a virus; however, it has not yet been identified. The lack of a permissive cell line for the putative kuchijirosho-causing agent (KCA) has hindered research on the identification of this pathogen. We inoculated brain extract prepared from kuchijirosho-affected fugu onto an established fugu cell line, fugu eye, and observed that cytopathic effect appeared 7 days after inoculation. Injection of the culture medium of infected fugu eye cells into fugu resulted in the onset of kuchijirosho, indicating that fugu eye cells are able to proliferate KCA. An infectious fraction separated by sodium iottalamate density gradient centrifugation showed a density of 1.15 g mL(-1) equivalent to that of KCA derived from affected fugu brain. To determine whether the genome of KCA is RNA or DNA based, nucleotide synthesis inhibitors were applied to inoculated fugu eye cell line to influence the production of KCA. 5-Fluorouracil but not IUdR showed a concentration-dependent inhibition of KCA yield. These results suggest that KCA is an RNA virus.     

Bioactive Bis(indole) Alkaloids from a Spongosorites sp. Sponge

Six new bis(indole) alkaloids (1–6) along with eight known ones of the topsentin class were isolated from a Spongosorites sp. sponge of Korea. Based on the results of combined spectroscopic analyses, the structures of spongosoritins A–D (1–4) were determined to possess a 2-methoxy-1-imidazole-5-one core connecting the indole moieties, and these were linked by a linear urea bridge for spongocarbamides A (5) and B (6). The absolute configurations of spongosoritins were assigned by electronic circular dichroism (ECD) computation. The new compounds exhibited moderate inhibition against transpeptidase sortase A and weak inhibition against human pathogenic bacteria and A549 and K562 cancer cell lines.     

Antibacterial Meroterpenoids,Merochlorins G–J from the Marine Bacterium Streptomyces sp.

Four new chlorinated meroterpenoids, merochlorins G−J (1−4), and 10, a dihydronaphthalenedione precursor, along with known merochlorins A (5) and C−F (6−9), were obtained from cultivation of the bacterium strain Streptomyces sp. CNH-189, which was isolated from marine sediment. The planar structures of compounds 1−4 and 10 were elucidated by interpretation of MS, UV, and NMR spectroscopic data. The relative configurations of compounds 1−4 were determined via analysis of nuclear Overhauser effect (NOE) spectroscopic data, after which their absolute configurations were established by comparing the experimental electronic circular dichroism (ECD) spectra of compounds 1−4 to those of previously reported possible enantiomer models and DP4 calculations. Compound 3 displayed strong antibacterial activities against Bacillus subtilis, Kocuria rhizophila, and Staphylococcus aureus, with MIC values of 1, 2, and 2 μg/mL, respectively, whereas compound 1 exhibited weak antibacterial effects on these three strains, with a 16−32 μg/mL MIC value range.     

Promising antidiabetic potential of fucoxanthin isolated from the edible brown algae Eisenia bicyclis and Undaria pinnatifida

In the present study, we investigated the antidiabetic potential of fucoxanthin via the inhibition of rat lens aldose reductase (RLAR), human recombinant aldose reductase (HRAR), advanced glycation end-product (AGE) formation, protein tyrosine phosphatase 1B (PTP1B), and α-glucosidase. Fucoxanthin displayed potent inhibitory activity against AGE formation and HRAR and RLAR activity. In addition, fucoxanthin showed potent inhibitory activity against PTP1B. However, it did not show α-glucosidase inhibitory activity below 200 μM. In addition, our kinetic study revealed that fucoxanthin competitively inhibited RLAR, while it showed mixed-type inhibition against PTP1B. In order to confirm enzyme inhibition, we predicted the 3D structure of PTP1B using Autodock 4.0 to simulate the binding of fucoxanthin. Docking simulation results demonstrated that three residues of PTP1B (Phe30, Phe52, and Gly183) interact with the two hydroxyl groups of fucoxanthin. In addition, the binding energy was negative (?7.66 kcal/mol), indicating that the three hydrogen bonds may stabilize the open form of the enzyme and potentiate tighter binding to the active site of PTP1B, resulting in more effective PTP1B inhibition. The results of the present study therefore clearly demonstrate the promising potential of fucoxanthin as a therapeutic intervention for the management of diabetes as well as diabetes-associated complications, which could be explored further.     

Analysis of differentially expressed genes in soybean leaf tissue of tolerant and susceptible cultivars under flooding stress revealed by RNA sequencing

Journal of Crop Science and Biotechnology - Flooding stress causes severe yield reduction in soybean worldwide. The development of stress-tolerant cultivars could be an effective measure to reduce...     

Effects of water temperature on mortality in Megalocytivirus‐infected rock bream Oplegnathus fasciatus (Temminck et Schlegel) and development of protective immunity

Rock bream iridovirus (RBIV) causes huge losses, especially in rock bream Oplegnathus fasciatus. Rock bream injected with RBIV and held at 29, 26, 23 or 20 °C had 100% mortality. Conversely, all infected fish held at 17 °C survived even after the temperature was progressively increased to 26 °C at 100 dpi. Rock bream exposed to virus and held for 2, 4 and 7 days at 23/26 °C before the temperature was reduced to 17 °C had mortality rates of 26.6/73.2%, 66.6/100% and 93.4/100%, respectively, through 100 dpi. When surviving fish had the water temperature increased from 17 to 26 °C at 100 dpi, they did not exhibit signs of disease and had low virus copy numbers (below 10³). To investigate the development of a protective immune, rock bream were infected with RBIV and held at 23 °C before shifting the water temperature to 17 °C at 4 dpi. All injected fish survived until 120 dpi. While 100% of the previously unexposed fish died, 80.2% of the previously infected fish survived. When the survivors were rechallenged again at 160 dpi, no further mortality occurred. The high survival rate of fish following rechallenge with RBIV indicates that protective immunity was established in the surviving rock bream.     

Monitoring of Acid Rain over Korean Peninsula

In order to investigate the temporal and spacial deposition characteristics of acid rain, five monitoring sites were set up in the central part of Korean Peninsula. Rainwater samples were collected by wet-only sampler from 1992 to 1997. The pH and conductivity values were measured and the major water soluble ionic components were also analyzed. Ion balance between anion and cation sum was calculated to check out the data quality of samples. The acidity of rainwater was influenced by the local sources and meteorological factors such as surface wind, moving path of storm, precipitation process, and so on. Backward trajectories were depicted to investigate the effect due to moving path of weather system. The rainwater shows strong acidity in winter and weak in summer. The pH and ion concentrations were highly dependent on synoptic weather system. In addition, we sampled fog/cloud at Mt. Sobaek (BAPMoN Station) from June to August 1995 and characterized the fog/cloud chemistry according to surface wind system of sampling site. The volume-weighted mean pH of fog/cloud samples is 4.39 at Mt. Sobaek during the sampling period.     

Studies of Spatial Variabilities of Airborne Metals Across Four Different Land-Use Types

The concentrations of seven metals (Fe, Pb, Mn, Ni, Cd, Cu, and Cr) associated with the total suspended particles (TSPs) were analyzed regularly from the four sampling sites of different land-use types within the boundary of Won Ju city, Korea during1991 through 1995. The mean concentration data for the four sitesselected to represent grassland, residential, commercial, and industrial areas fell in a relatively broad range of: 1440–2240 (Fe), 88–326 (Pb), 2–4 (Cd), 8–21 (Cr),194–469 (Cu), 32–95 (Mn), and 15–26 (Ni) ng m^-3. The data, when compared across the different study sites, generally exhibited systematic trends in accordance withthe site-selection scheme; most metals exhibited increase in their concentration levels across grassland through industrial site. Examinations of data also indicated the possibility that spatial factors play complicated roles on both long- and short-term distribution of metals. From all four sites studied, severalmetals (e.g., Fe, Pb, Mn, Ni, and Cd) consistently showed theirseasonal trends characteristic of high winter/spring values. In addition, the analysis of long-term distribution trendsindicated that the concentrations of many metals droppedsteadily at four sites (e.g., Fe, Pb, and Mn). When these metaldata were compared among different sites (land-use types), significant correlations were seen frequently for such metals asFe, Pb, Cd, and Cr. Investigations of inter-metal relationshipsindicated that strong correlations were more abundant from such metal pairs as Fe-Pb, Pb-Mn, and Mn-Fe. In addition, the cases for such strong correlations were seen more abundantly from grassland (and residential) than industrial (and commercial) site. Factor analysis was also conducted to distinguish sourceprocesses affecting metal distributions in the study area. Results of this analysis suggest that the metal distributions ofthe individual sites may be affected most significantly by distinctive source processes of their own.     

Isolation and characterization of antioxidant protein fractions from melinjo (Gnetum gnemon) seeds

The protein from the seeds of melinjo ( Gnetum gnemon ) was purified using a precipitation method and ion exchange chromatographic techniques to identify the potent antioxidant and free radical scavenging activities. Two antioxidant protein fractions were isolated from G. gnemon seed with molecular weights of approximately 30 kDa (Gg-AOPI) and 12 kDa (Gg-AOPII) by SDS-PAGE. The N-terminal amino acid sequence of Gg-AOPII is Gly-Asn-Gly-Lys-Ala-Thr-Val-Ala-Ile-Leu-Val-Lys-Glu-Lys-Val-Glu-Tyr-Gly-Glu-Glu, and the result of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis showed that they were distinct from each other; no protein in database matching was found to both Gg-AOPI and Gg-AOPII. The antioxidant or free radical scavenging activities of Gg-AOPs were investigated by employing in vitro assay systems including the inhibition of linoleic acid autoxidation, scavenging effect on α,α-diphenyl-β-picrylhydrazyl free radical (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), reducing power, chelating abilities of metal ions Cu(2+) and Fe(2+), and protections against hydroxyl radical-mediated DNA damages. The result showed that two protein fractions exhibited significant (p < 0.05) antioxidant activities against free radicals such as DPPH, ABTS, and superoxide anion and showed activities similar to those of glutathione (G-SH) and BHT in a linoleic acid emulsion assay system. Moreover, Gg-AOPI and Gg-AOPII also exhibited notable reducing power and strong chelating effect on Fe(2+) and protected hydroxyl radical induced oxidative DNA damage. The data obtained by the in vitro systems obviously established the antioxidant potency of Gg-AOPs.