Estimation of flood risk index considering the regional flood characteristics: a case of South Korea

Global warming is increasing the variability of climate change and intensifying hydrologic cycle components including precipitation, infiltration, evapotranspiration, and runoff. These changes increase the chance of more severe and frequent natural conditions, and limit ecosystem function and human activities. Adaptation to climate change requires assessment of the potential disaster risk. The objectives of this study were to estimate the flood risk index (FRI) considering regional flood characteristics at the national level and to prioritize the factors affecting flood risk through principal component analysis. FRI was estimated based on the Delphi survey results from 50 water resources experts in South Korea. The potential risk analysis was conducted for 229 local governments in South Korea. The results showed that natural and social factors were more influential flood risk factors to South Korea than administrative and economic and facility factors. Specifically, natural, social, administrative and economic, and facility factors were, respectively, highest at Jindo-Gun in Jennam-Do, Gumi-Si in Kyongsanbuk-Do, Dong-Gu in Incheon-Si, and Suwon-Si, Kyonggi-Do. Overall, the highest FRI is shown in Anyang-Si, Kyongggi-Do. The spatial distribution of the FRI was high in the southeastern coastal region and basins of the two biggest rivers in South Korea, and normalized flood frequency followed spatial patterns similar to FRIs. This study provided information on the relative flood risk index among administrative units for investment prioritization in flood risk management. In this regard, the suggested FRI is expected to significantly contribute to methodical and economic improvements in budget allocations for flood risk management.     

Amino Alcohols from the Ascidian Pseudodistoma sp

Seven new amino alcohol compounds, pseudoaminols A–G (1–7), were isolated from the ascidian Pseudodistoma sp. collected off the coast of Chuja-do, Korea. Structures of these new compounds were determined by analysis of the spectroscopic data and from chemical conversion. The presence of an N-carboxymethyl group in two of the new compounds (6 and 7) is unprecedented among amino alcohols. Several of these compounds exhibited moderate antimicrobial activity and cytotoxicity, as well as weak inhibitory activity toward Na⁺/K⁺-ATPase.     

Comparison of oyster shell and calcium hydroxide as liming materials for immobilizing cadmium in upland soil

Cadmium is both readily available and highly toxic to plants and animals. Our objectives were to evaluate the effect of oyster shell as a liming material on reducing plant cadmium (Cd) uptake and to compare oyster shell and Ca(OH)₂, a common liming material in Korea. Ground oyster shell and Ca(OH)₂ were applied at 0, 2, 4, and 8 Mg Ca per hectare to an upland soil contaminated manually with CdSO₄ (total Cd 8.96 mg kg^?1). Radish (Raphanus sativa L.) was sown on the contaminated soil. Oyster shell was less effective at increasing soil pH and net negative charge than Ca(OH)₂, but more effective at suppressing radish Cd uptake in both roots and shoots. The portion of Cd that is strongly bound to soil (fraction 5) increased more with oyster shell than with Ca(OH)₂. Radish plant Cd concentration was positively correlated with 0.1 N HCl-extractable Cd and negatively correlated with the residual Cd fraction (F5), indicating that an increase in the strongly bound Cd fraction played an important role in reducing radish Cd uptake in soil to which oyster shell was applied. The greater potential of oyster shell to decrease Cd extractability in soil and plant Cd uptake compared to Ca(OH)₂ might be attributed to the layered morphology of oyster shells. Based on these results, oyster shell could be a very good alternative liming material to reduce Cd phytoavailability in Cd-contaminated soil.     

Identification and characterization of a cathepsin L-like cysteine protease from Taenia solium metacestode

Taenia solium metacestode, a larval pork tapeworm, is a causative agent of neurocysticercosis, one of the most common parasitic diseases in the human central nervous system. In this study, we identified a cDNA encoding for a cathepsin L-like cysteine protease from the T. solium metacestode (TsCL-1) and characterized the biochemical properties of the recombinant enzyme. The cloned cDNA of 1216 bp encoded 339 amino acids with an approximate molecular weight of 37.6 kDa which containing a typical signal peptide sequence (17 amino acids), a pro-domain (106 amino acids), and a mature domain (216 amino acids). Sequence alignments of TsCL-1 showed low sequence similarity of 27.3-44.6 to cathepsin L-like cysteine proteases from other helminth parasites, but the similarity was increased to 35.9-55.0 when compared to mature domains. The bacterially expressed recombinant protein (rTsCL-1) did not show enzyme activity; however, the rTsCL-1 expressed in Pichia pastoris showed typical biochemical characteristics of cysteine proteases. It degraded human immunoglobulin G (IgG) and bovine serum albumin (BSA), but not collagen. Western blot analysis of the rTsCL-1 showed antigenicity against the sera from patients with cysticercosis, sparganosis or fascioliasis, but weak or no antigenicity against the sera from patients with paragonimiasis or clonorchiasis.     

Synthesis, structure analyses, and characterization of novel epigallocatechin gallate (EGCG) glycosides using the glucansucrase from Leuconostoc mesenteroides B-1299CB

In this study, three epigallocatechin gallate glycosides were synthesized by the acceptor reaction of a glucansucrase produced by Leuconostoc mesenteroides B-1299CB with epigallocatechin gallate (EGCG) and sucrose. Each of these glycosides was then purified, and the structures were assigned as follows: epigallocatechin gallate 7-O-alpha-D-glucopyranoside (EGCG-G1); epigallocatechin gallate 4'-O-alpha-D-glucopyranoside (EGCG-G1'); and epigallocatechin gallate 7,4'-O-alpha-D-glucopyranoside (EGCG-G2). One of these compounds (EGCG-G1) was a novel compound. The EGCG glycosides exhibited similar or slower antioxidant effects, depending on their structures (EGCG > or = EGCG-G1 > EGCG-G1' > EGCG-G2), and also manifested a higher degree of browning resistance than was previously noted in EGCG. Also, EGCG-G1, EGCG-G1', and EGCG-G2 were 49, 55, and 114 times as water soluble, respectively, as EGCG.     

Histopathology of Infection and Colonization of Susceptible and Resistant Port-Orford-Cedar by Phytophthora lateralis

ABSTRACT Port-Orford-cedar (POC) root disease, caused by Phytophthora lateralis, continues to kill POC in landscape plantings and natural forests in western North America. POC trees resistant to P. lateralis have been identified and propagated. Cytological observations of P. lateralis in susceptible and resistant roots and stems were made with light and transmission electron microscopy to identify resistance mechanisms. No differences in infection pathway and initial colonization were observed between susceptible and resistant roots, although there were differences in the rate and extent of development. Germ tubes formed appressoria, and penetration hyphae grew either between or directly through epidermal cell walls; inter- and intracellular hyphae colonized the root cortex. In susceptible roots, hyphae penetrated into the vascular system within 48 h of inoculation. In contrast, hyphae in roots of resistant seedlings grew more slowly in cortical cells and were not observed to penetrate to the vascular tissues. In resistant roots, infection was marked by general thickening of cortical cell walls, wall appositions around penetrating hyphae, collapse of cortical cells, and accumulation of osmophillic granules around hyphae. In susceptible stems, hyphae grew inter- and intracellularly in all cells of the secondary phloem except fiber cells, but were concentrated in sieve and parenchyma cells in the functional phloem. The pattern of penetration and colonization of hyphae was similar in the resistant stems, except that hyphae were found in the fiber cells of the xylem. In resistant stems, there were fewer hyphae in the functional phloem, and cytological changes such as damaged nuclei and disintegrated cytoplasm were evident. Structural changes in resistant stems included collapsed cells, wall thickening, secretory bodies, apposition of electron dense materials, and crystals in cell walls.     

Evidence of shedding of porcine circovirus type 2 in milk from experimentally infected sows

Detection of porcine circovirus type 2 (PCV2) was to evaluate the milk from experimentally infected sows using polymerase chain reaction (PCR) and virus isolation. Six pregnant sows were inoculated intranasally with PCV2 at 93 days of gestation, and milk samples were collected from all sows at 1, 3, 6, 9, 12, 15, 18, 21, 24, and 27 days of lactation. PCV2 was detected in milk as early as day 1 of lactation in all six sows. Thereafter, all infected sows remained positive by PCR for PCV2 in milk until 27 days of lactation. In addition, PCV2 itself was isolated from milk collected from a virus-infected sows. These results suggest that PCV2 may be shed in milk following infection of pregnant sows by the virus.     

Rat allogeneic mesenchymal stem cells did not prolong the survival of corneal xenograft in a pig-to-rat model

Objective  Recent reports have demonstrated that mesenchymal stem cells (MSCs) can modulate/suppress immunologic responses through interactions with different immune cells. We performed this study in order to investigate the immunomodulatory effects of MSCs in corneal xenotransplantation.
Animals studied  Pig and rat.
Procedures  We orthotopically transplanted pig corneas into rats and topically applied allogeneic rat MSCs to the corneas for 2 h immediately after transplantation. Graft survival was clinically assessed using slit-lamp biomicroscopy and the median survival time (MST) was calculated. The rejected grafts were histologically examined using antibodies against CD4, CD8, CD161, and CD68. The expression of IL-2, IL-6, IL-10, and IFN-γ was also evaluated in the rejected grafts using an enzyme-linked immunosorbent assay.
Results  The survival of corneal xenografts was not significantly prolonged by MSC application (MST 10.5 days) compared with the controls (MST 9.67 days) ( P  = 0.4189). Histologically, the rejected grafts in both groups were massively infiltrated with neutrophils and macrophages. Some CD8⁺ T cells and rare NK cells were found in the rejected grafts. The levels of IL-6 and IL-10 were significantly increased in the rejected grafts from MSC-treated rats compared with the grafts from MSC-untreated rats. However, the levels of IL-2 and IFN-γ were not different between the two groups.
Conclusions  Topical application of allogeneic rat MSCs was ineffective in prolonging corneal xenograft survival in a pig-to-rat model.     

Influence of water-dispersible colloids from organic manure on the mechanism of metal transport in historically contaminated soils: coupling colloid fractionation with high-energy synchrotron analysis

Purpose

Colloid-facilitated transport of metals is widely observed while manure is used for the improvement of contaminated soil. Details on the mechanism of colloid-associated metal transport are still lacking. This work investigated the nature of water-dispersible colloids (WDC) from different organic manures, differentiated the significance of clay and organic colloids in the metal transport, and finally provided direct and quantitative evidence for the importance of WDC in the colloid-facilitated transport of metals.

Materials and methods

Column experiments were conducted to assess the overall significance of WDC from effective microbial inoculated manure (EM) and leaf mulch (LM) for metal transport in alkali-contaminated soil. The properties of organic colloids such as hydrophilicity, aromaticity, and functional characteristics were analyzed by DAX-8 resin column, specific UV absorbance, and Fourier-transform infrared spectroscopy, respectively. Colloid identification and metal species determination were conducted using a combination of X-ray absorption near-edge structure, X-ray fluorescence spectroscopy, and transmission electron microscopy coupled with energy-dispersive X-ray analysis.

Results and discussion

Approximately 100 % of Pb, 69 % of Zn, and 38 % of Cu in the colloidal particles came from soil clay in the presence of EM colloids, while more than 80 % of Pb, Zn, and Cu in the LM colloids. Combined with the quantities of colloidal metals, it revealed that clay release was inhibited in the former and enhanced in the latter. The quantities of Cu and Zn associated with the EM colloids were much higher than that with the LM colloids. The contrary result was observed for Pb. LM colloids increased the quantities of organically associated Pb significantly.

Conclusions

Clay-associated metal transfer was influenced by the nature of WDC. Microbial manure colloids inhibited the clay-associated transfer of metals in the soils probably due to the presence of polysaccharide and microbially derived extracellular proteins. Leaf mulch colloids, with more hydrophobicity and aromaticity, enhanced the clay-facilitated transfer of metals in the soils.

     

Purification and characterization of proteases from Bacillus amyloliquefaciens isolated from traditional soybean fermentation starter

Bacillus amyloliquefaciens FSE-68 isolated from meju, a Korean soybean fermentation starter, was identified on the basis of biophysical tests and 16S rRNA gene sequence. A neutral metalloprotease (NPR68) and an alkaline serine-protease (APR68) were purified by ammonium sulfate precipitation and cation exchange chromatography and identified on the basis of their activities at different pH values and the selective protease inhibitors. The molecular weights of NPR68 and APR68 measured with ESI-MS were 32743 (+/- 0.8) and 27443 (+/- 0.5) Da, respectively. Against oxidized insulin chains, the NPR68 has a cleavage preference at the site where leucine is located as a P1' residue followed by phenylalanine, and the APR68 has broad specificity and favors leucine at the P1 site. These results indicate that the proteases are natural variants of subtilisin and bacillolysin.