The predation of trumpet shell, Charonia sp., on eight different marine invertebrate species

In this study, predation of the trumpet shell, Charonia sp., on different invertebrate prey species, e.g. starfish, Asterina pectinifera and Asterias amurensis, abalone Haliotis discus hannai, clam Anadara broughtonii and Tapes phillipiarum, and sea urchin Hemicentrotus pulcherrimus and Anthocidaris crassispina, was measured in a laboratory experiment. Each prey species was placed in a tank with a trumpet shell; prey species were not combined. Each combination of prey and trumpet shell was replicated three times. Trumpet shells did not prey on economically important shellfishes, including Anadara broughtonii, Tapes phillipiarum and Haliotis discus hannai. Sea stars were most preferred by the trumpet shell. The following preference gradient from most to least preferred was found: sea stars > sea cucumber > sea urchin. In selected situations, trumpet shells may be a means of biological control of predators of economically important shellfish.     

Gene expression profile by 2,3,7,8-tetrachlorodibenzo-p-dioxin in the liver of wild-type (AhR+/+) and aryl hydrocarbon receptor-deficient (AhR-/-) mice

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is one of the most toxic environmental pollutants that cause various biological effects on mammals. The purpose of our study was to identify the genes involved in hepatotoxicity and hepatocarcinogenesis caused by TCDD. C57BL/6 (AhR+/+, wild type) and B6.129-AhR/J (AhR-/-, knock out) mice were injected i.p. with a single treatment of TCDD at the dose of 100 microg/kg body weight. Relative liver weight was significantly increased at 72 hr after TCDD treatment without an apparent histopathological change in AhR+/+ mice (p<0.05). TCDD treatment also significantly increased activity of serum alanine aminotransferase in AhR-/- mice (p<0.05). The liver was analyzed for gene expression profiles 72 hr later. As compared with AhR-/- mice, the expression of 51 genes (>3-fold) was changed in AhR+/+ mice; 28 genes were induced, while 23 genes were repressed. Most of the genes were associated with chemotaxis, inflammation, carcinogenesis, acute-phase response, immune responses, cell metabolism, cell proliferation, signal transduction, and tumor suppression. This study suggests that the microarray analysis of genes in the liver of AhR+/+ and AhR-/- mice may help to clarify the mechanism of AhR-mediated hepatotoxicity and hepatocarcinogenesis by TCDD.     

EK-2612, a new cyclohexane-1,3-dione possessing selectivity between rice (Oryza sativa) and barnyardgrass (Echinochloa crus-galli)

A newly synthesized experimental compound, EK-2612 is one of the class of cyclohexane-1,3-diones which are commonly known to be grasskillers. A greenhouse study was conducted to evaluate the herbicidal performances of EK-2612 on several grass species in comparison with tralkoxydim, a commercialized cyclohexanedione derivative. Like tralkoxydim, the compound EK-2612 showed excellent control efficacy on most grass weeds tested through foliar application rates between 250 and 63 g AI ha(-1). Unlike tralkoxydim, however, EK-2612 showed a good rice safety, and there was no rice damage observed at the level below 125 g AI ha(-1), while rice injury developed at the same application rates of tralkoxydim. With this rice safety, EK-2612 controlled barnyardgrass effectively up to the two-leaf stage under both submerged and dried paddy conditions. An in vitro ACCase assay indicated that EK-2612 is a strong ACCase inhibitor; however, the dose-response was not substantially different in rice and barnryardgrass, showing I50 values of 0.1 and 0.12 microM, respectively. These results suggest that the compound EK-2612 is targeting plant ACCase, but the whole-plant rice safety is not attributable to a different inhibition of the target site in rice from that in barnyardgrass.     

Multi-Step Enzymatic Production and Purification of 2-Keto-3-Deoxy-Galactonate from Red-Macroalgae-Derived Agarose

2-keto-3-deoxy sugar acids, which have potential as precursors in medicinal compound production, have gained attention in various fields. Among these acids, 2-keto-3-deoxy-l-galactonate (KDGal) has been biologically produced from D-galacturonate originating from plant-derived pectin. KDGal is also found in the catabolic pathway of 3,6-anhydro-l-galactose (AHG), the main component of red-algae-derived agarose. AHG is converted to 3,6-anhydrogalactonate by AHG dehydrogenase and subsequently isomerized to KDGal by 3,6-anhydrogalactonate cycloisomerase. Therefore, we used the above-described pathway to produce KDGal from agarose. Agarose was depolymerized to AHG and to agarotriose (AgaDP3) and agaropentaose (AgaDP5), both of which have significantly higher molecular weights than AHG. When only AHG was converted to KDGal, AgaDP3 and AgaDP5 remained unreacted. Finally, KDGal was effectively purified from the enzymatic products by size-exclusion chromatography based on the differences in molecular weights. These results show that KDGal can be enzymatically produced and purified from agarose for use as a precursor to high-value products.     

Liquid penetration in different cells of two hardwood species

Two experimental techniques were used to test the water permeability of two Korean hardwood species: diffuse porous Populus tomentiglandulosa T. Lee (eunsasi poplar) and ring porous white oak, Quercus serrata Thunb (konara oak). The first technique measured the void volume filled at different moisture content (MC) levels. Samples were treated with water via a schedule of full-cell impregnation. A significant relation between MC and permeability (the fractional void volume) was found. A reduction in liquid permeability was observed at MC above the fiber saturation point (FSP), whereas the opposite result was observed at MC below FSP due to the effect of the voids available in the wood. However, the differences of increased permeability from MC level 20% to 0% were found satistically the same in either wood species. The second technique measured the speed of liquid penetration in vessels, fibers, and rays with no application of external pressure. In this method, liquid flow was captured via video and the penetration speed was measured. Vessels, fibers, and rays in poplar were found to be more permeable than those in oak. Different anatomical factors such as cell diameter, cell length, pit number, pit aperture area, and thickness of the pit membrane seemed to be responsible for the variation of liquid flow rate in different cells of the two hardwood species.     

Mercury and Methylmercury in Freshwater Fish and Sediments in South Korea Using Newly Adopted Purge and Trap GC-MS Detection Method

The use of purge and trap gas chromatography–mass spectrometry (GC-MS) technique for the determination of methylmercury in biological and sediment samples was described. The GC-MS detection system was combined with the dithizone extraction method for biological samples and the distillation method for sediment samples to alleviate matrix interference problems. The method was validated by analysis of CRMs such as SRM 966 (human blood), BCR 463 (tuna fish), IAEA 407 (fish), ERM CC580 (estuarine sediment), and IAEA 405 (sediment). The performance of the purge and trap GC-MS method was also tested on field samples of freshwater fish and sediment. The results were compared with those of the GC-ECD and the GC-CVAFS, which were used widely for methylmercury analysis. Additionally, total mercury and methylmercury levels in freshwater fish and sediments from various reservoirs and streams in Korea were measured to understand mercury contamination status in Korean peninsula. Methylmercury concentrations in freshwater fish were found to correlate with body weight, diet habit, and food availability. In sediment, total mercury concentrations correlated with methylmercury concentrations and organic matter such as %C and %S. However, no significant relationships between methylmercury and sediment organic matter have been found.     

Effects of an environmental friendly slow-releasing woodchip fertilizer on cabbage production

Wood from three tree species was used for making slow-releasing woodchip fertilizer. Fertilizer made from Populus tomen-tiglandulosa retained the highest amounts of N (29.04%), P2O5 (26.03%) and K2O (16.93%). On the other hand, woodchip fertilizer made from Pinus koraiensis retained the lowest amounts of N (26.22%), P2O5 (21.80%) and K2O (14.49%). A field experiment was performed in a 50 m2 experimental plot at Gangwon Agricultural Research and Extension Services, Chuncheon, Korea from August to November 1999. The effects of a general fertilizer along with compost and slow releasing woodchip fertilizer without compost on the cabbage production were observed. Cabbage production parameters, such as top height, head weight, head height, head width, number of outer and inner leaves, leaf width and head length, increased in the field where Larix kaempferi woodchip fertilizer was added as a basal dose. The result showed that the woodchip fertilizer made from Pinus koraiensis had faster releasing properties compared to other woodchip fertilizers. Without adding any compost in the woodchip fertilized field, woodchip fertilizer showed a superior outcome over a general chemical fertilizer. Although the amount of woodchip fertilizer was larger compared to that of a chemical fertilizer, it increased cabbage production.     

Effects of the Dietary Fermented Tuna By‐product Meal on Growth,Blood Parameters,Nonspecific Immune Response,and Disease Resistance in Juvenile Olive Flounder,Paralichthys olivaceus

This study evaluated the effects of dietary fermented tuna by‐product meal (FTBM) in juvenile olive flounder, Paralichthys olivaceus. Five diets were formulated to replace fishmeal (FM) with FTBM at 0% (FTBM₀), 12.5% (FTBM_12.5), 25.0% (FTBM₂₅), 37.5% (FTBM_37.5), or 50% (FTBM₅₀). After 8 wk, weight gain, specific growth rate, and feed efficiency of fish fed FTBM₀ and FTBM_12.5 diets were significantly higher than fish fed the other diets (P < 0.05). Also, mean cumulative survival rates (%) of fish fed the FTBM₀ and FTBM_12.5 diets were significantly higher than those fed FTBM₅₀ diet at Day 9 postchallenge with Edwardsiella tarda (P < 0.05). Protein efficiency ratio of fish fed FTBM₀ and FTBM_12.5 diets was significantly higher (P < 0.05) than fish fed diets FTBM_37.5 and FTBM₅₀. Broken‐line regression analysis of weight gain showed an optimal FM replacement level of 10.65% with FTBM. Therefore, the optimal dietary inclusion of FTBM in juvenile olive flounder diets could be greater than 10.65% but less than 12.5% without any adverse physiological effects on fish health.     

New Cyclic Lipopeptides of the Iturin Class Produced by Saltern-Derived Bacillus sp. KCB14S006

Salterns, one of the most extreme natural hypersaline environments, are a rich source of halophilic and halotolerant microorganisms, but they remain largely underexplored ecological niches in the discovery of bioactive secondary metabolites. In continued efforts to investigate the metabolic potential of microbial populations from chemically underexplored sites, three new lipopeptides named iturin F₁, iturin F₂ and iturin A₉ (1–3), along with iturin A₈ (4), were isolated from Bacillus sp. KCB14S006 derived from a saltern. The structures of the isolated compounds were established by 1D-, 2D-NMR and HR-ESIMS, and their absolute configurations were determined by applying advanced Marfey’s method and CD spectroscopy. All isolates exhibited significant antifungal activities against various pathogenic fungi and moderate cytotoxic activities toward HeLa and src^ts-NRK cell lines. Moreover, in an in vitro enzymatic assay, compound 4 showed a significant inhibitory activity against indoleamine 2,3-dioxygenase.     

Potential use of ground brown rice for weanling pigs

The purpose of the current study was to assess the effects of substituting corn with ground brown rice on growth performance, immune status, and gut microbiota in weanling pigs. Seventy-two weanling pigs (28 d old with 6.78 ± 0.94 kg body weight [BW]) were randomly allotted to two dietary treatments with six pens and six pigs (three barrows and gilts) per pen within a randomized complete block design. The control pigs were fed a typical diet for weanling pigs based on corn and soybean meal diet (control diet: CON), and the other pigs were fed a formulated diet with 100% replacement of corn with ground brown rice for 35d (treatment diet: GBR). Growth performance, immune status, and gut microbiota of weanling pigs were measured. The substitution of corn with GBR did not affect growth performance or diarrhea frequency. Additionally, there were no differences in white blood cell number, hematocrit, cortisol, C-reactive protein, and serum tumor necrosis factor-alpha levels between pigs fed CON or GBR for the first 2 wk after weaning. However, weanling pigs fed GBR had lower (P < 0.05) serum transforming growth factor-beta 1 level than those fed CON. Furthermore, weanling pigs fed GBR had increased (P < 0.05) relative abundance of phylum Firmicutes and genus Lactobacillus and Streptococcus and decreased (P < 0.05) relative abundance of phylum Bacteroidetes and genus Clostridium and Prevotella in the gut microbiota compared with those fed CON. In conclusion, there was no significant difference in growth performance when corn was replaced with ground brown rice in diets for weanling pigs. Furthermore, the substitution of corn with ground brown rice in weaning diet modulated immune status and gut microbiota of pigs by increasing beneficial microbial communities and reducing harmful microbial communities. Overall, ground brown rice-based diet is a potential alternative to corn-based diet without negative effects on growth performance, immune status, and gut microbiota changes of weanling pigs.