Influence of land cover, point source pollution, and granularity on the distribution of metals, metalloids, and organic matter in the river and stream sediments in the Republic of Korea.

With increasing anthropogenic activities, rivers and streams have become vulnerable to pollution; therefore, monitoring potential contaminants and the pollution status of surface sediments is essential. This study analyzed the concentrations of organic matter, metals, and metalloids; indices for organic, metal, and metalloid pollution; and ecological risk in river and stream sediments at 82 stations across Korea in 2017, 2018, and 2020. We performed bootstrapped analysis of variance, principal component analysis, and cluster analysis and used a structural equation model (SEM) to investigate spatiotemporal changes in the pollution status, main pollutant chemicals, and the exogenous factors affecting pollution status. The results suggest no significant differences in any of the twelve single chemical parameters and three pollution indices across the surveyed years. Metals, metalloids (Cu, Zn, Pb, and Hg), and organic matter with nutrients were identified as the main pollutants. The SEM demonstrated the significant influence of pollution sources-water used for industrial purposes, landfill wastewater discharge, and industrial wastewater discharge-on organic pollution, metal and metalloid pollution load, and environmental toxicity. This study identified consistently polluted areas, proposed additional management policies and stricter regulations on major point pollution sources rather than on broader land-use types, and suggested the combined consideration of metal toxicity risk with nutrient accumulation for future risk assessments.

Is scat marking a reliable tool for otter census and surveys at the landscape scale?

Biological significance of scat marking by otters has been a controversial subject among scientists. Using multiyear (2014-2017) data of otter spraint counts in South Korea, this study aimed to test whether the observed pattern of spraint presence/absence is driven by detection error and if/how scat counts can be a proxy for otter abundance at the landscape scale. To test the first hypothesis, spraint presence/absence was analyzed through occupancy models, which relied on environmental variables related to otter detectability and presence. Spraint count models were used to test the second hypothesis against resource-related covariates in combination with landscape, anthropogenic, and climate variables through machine learning algorithms (MLAs). The detection probability has specifically decreased in areas characterized by high rainfall and human population densities, whereas the probability has increased near food-rich sites, characterized by high marking frequencies. The temporal trends of spraint count predictions were in line with changes in the diversity of fish communities in 2014-2017 instead of fish biomass, suggesting that the availability of feeding resources is higher where fish communities are more diverse. Because diverse fish communities can attract otters, fish diversity conservation is critical for preserving this mammal's populations. This fine scale four-year monitoring has contributed to the disentanglement of the role of spraint presence/absence and spraint counts in detectability and population trends. This will assist in identifying key resource areas and planning strategies to promote otter conservation and dispersal dynamics.

A Hybrid Zeolite Membrane-Based Breakthrough for Simultaneous CO2 Capture and CH4 Upgrading from Biogas.

Biogas is an environmentally friendly and sustainable energy resource that can substitute or complement conventional fossil fuels. For practical uses, biogas upgrading, mainly through the effective separation of CO2 (0.33 nm) and CH4 (0.38 nm), is required to meet the approximately 90-95% purity of CH4, while CO2 should be concomitantly purified. In this study, a high CO2 perm-selective zeolite membrane was synthesized by heteroepitaxially growing a chabazite (CHA) zeolite seed layer with a synthetic precursor that allowed the formation of all-silica deca-dodecasil 3 rhombohedral (DDR) zeolite (with a pore size of 0.36 × 0.44 nm2). The resulting hydrophobic DDR@CHA hybrid membrane on an asymmetric α-Al2O3 tube was thin (ca. 2 µm) and continuous, thus providing both high flux and permselectivity for CO2 irrespective of the presence or absence of water vapor (the third largest component in the biogas streams). To the best of our knowledge, the CO2 permeance of (2.9 ± 0.3) × 10-7 mol m-2 s-1 Pa-1 and CO2/CH4 separation factor of ca. 274 ± 73 at a saturated water vapor partial pressure of ca. 12 kPa at 50 °C have the highest CO2/CH4 separation performance yet achieved. Furthermore, we explored the membrane module properties of the hybrid membrane in terms of the recovery and purity of both CO2 and CH4 under dry and wet conditions. Despite the high intrinsic membrane properties of the current hybrid membrane, reflected by the high permeance and SF, the corresponding module properties indicated that high-performance separation of CO2 and CH4 for the desired biogas upgrading was achieved at a limited processing capacity. This supports the importance of understanding the correlation between the membrane and module properties, as this will provide guidance for the optimal operating conditions.

Habitat Characteristics Coincidence of Dead and Living Long-Tailed Gorals (Naemorhedus caudatus) According to Extreme Snowfall.

The long-tailed goral (Naemorhedus caudatus) is a critically endangered herbivore in South Korea. Despite government efforts to recover the population through reintroduction programs, the animal remains vulnerable to heavy snowfall. From March to June 2010, 24 animals were found dead due to heavy snowfall in the Wangpi Stream basin. In this study, we hypothesized that gorals that died due to snowfall are low-status individuals that lived in the sub-optimal or non-suitable areas. Using the occurrence data from extensive field surveys from 2008 to 2010 in the Wangpi Stream and the carcass location data, we (1) defined the goral habitat characteristics and (2) compared the habitat characteristics between dead and living gorals using ensemble species distribution modeling. The results suggested that the sites where dead gorals were found were highly related to typical goral habitats. These results implied that the optimal goral habitats could become uninhabitable following heavy snowfall. Most of the dead animals were pregnant females or were young, implying that they could not escape their primary habitats due to lower mobility. Thus, when there is a climate catastrophe, the optimal goral habitats should be considered for rescue and artificial feeding.

Assessment of the Behavioural Response of Korean Water Deer (Hydropotes inermis argyropus) to Different Fence Heights.

Fences have been widely implemented to reduce the risk of wildlife-vehicle collisions, wildlife disease spread, and crop damage. To manufacture fences, it is imperative to assess the behavioural responses of the target species. Here, we investigated the success rate of fences and classified eight behavioural responses of Korean water deer (Hydropotes inermis argyropus) to different fence heights. We explored the association of 801 behavioural responses and defined a threshold based on 40 events by applying non-metric multidimensional scaling and a binary logistic generalised linear mixed model. With fences lower and higher than 1.2 m, recession and rest were the dominant behaviours, respectively, before the deer crossed the fences by performing vertical and running jumps. Considering all independent events, 0.9 m was the marginal threshold, with highly variable outliers over this value. Placing exit pathways for deer and eliminating possible resting areas outside fences are essential for reducing the number of successful jump attempts. The optimal fence height could differ based on conditional factors; however, we recommend a height of 1.5 m considering the cost and roadkill risk. In conclusion, exploring and classifying the behavioural responses of the target species may be critical for establishing appropriate fence protocols.

Spatial patterning of chlorophyll a and water-quality measurements for determining environmental thresholds for local eutrophication in the Nakdong River basin.

Management of water-quality in a river ecosystem needs to be focused on susceptible regions to eutrophication based on proper measurements. The stress-response relationships between nutrients and primary productivity of phytoplankton allow the derivation of ecologically acceptable thresholds of stressors under field conditions. However, spatio-temporal variations in heterogeneous environmental conditions have hindered the development of locally applicable criteria. To address these issues, we utilized a combination of a geographically specialized artificial neural network (Geo-SOM, geo-self-organizing map) and linear mixed-effect models (LMMs). The model was applied to a 24-month dataset of 54 stations that spanned a wide spatial gradient in the Nakdong River basin. The Geo-SOM classified 1286 observations in the basin into 13 clusters that were regionally and seasonally distinct. Inclusion of the random effects of Geo-SOM clustering improved the performance of each LMM, which suggests that there were significant spatio-temporal variations in the Chla-stressor relationships. These variations arise owing to differences in background seasonality and the effects of local pollutant variables and land-use patterns. Among the 16 environmental variables, the major stressors for Chla were total phosphate (TP) as a nutrient and biological oxygen demand (BOD) as a non-nutrient according to the results of both Geo-SOM and LMM analyses. Based on LMMs with the random effect of the Geo-SOM clusters on the intercept and the slope, we can propose recommended thresholds for TP (18.5 µg L-1) and BOD (1.6 mg L-1) in the Nakdong River. The combined method of LMM and Geo-SOM will be useful in guiding appropriate local water-quality-management strategies and in the global development of large-scale nutrient criteria.

An Extrinsic-Pore-Containing Molecular Sieve Film: A Robust, High-Throughput Membrane Filter.

MFI type zeolites with 10-membered-ring pores (ca. 0.55 nm) have the ability to separate p-xylene (ca. 0.58 nm) from its bulkier isomers. Here, we introduced non-zeolitic micropores (ca. 0.6-1.5 nm) and mesopores (ca. 2-7 nm) to a conventional microporous MFI type zeolite membrane, yielding an unprecedented hierarchical membrane structure. The uniform, embedded non-zeolitic pores decreased defect formation considerably and facilitated molecular transport, resulting in high p-xylene perm-selectivity and molar flux. Specifically, compared to a conventional, crack network-containing MFI membranes of similar thickness (ca. 1 µm), the mesoporous MFI membranes showed almost double p-xylene permeance (ca. 1.6±0.4×10-7  mol m-2 s-1 Pa-1 ) and a high p-/o-xylene separation factor (ca. 53.8±7.3 vs. 3.5±0.5 in the conventional MFI membrane) at 225 °C. The embedded non-zeolitic pores allowed for decreasing the separation performance degradation, which was apparently related to coke formation.

Drivers shaping episodic and gradual changes in phytoplankton community succession: Taxonomic versus functional groups.

Describing temporal changes in phytoplankton communities is complicated owing to (i) multivariate environmental drivers, (ii) inter-specific relationships, and (iii) various species. With long-term research data from the lower Nakdong River from 1993 to 2016, we examined the temporal changes at two scales-episodic (from weekly to monthly) and long-term (yearly)-and screened the potential environmental drivers. Phytoplankton community component patterns were modeled with the drivers as covariates, using multivariate autoregressive state-space (MARSS) models, to assess their response to environmental drivers and biotic interactions. We assumed that compared to taxonomic classification, functional classification would obtain a better identification of community response to temporal variability. Over 24 years, the succession patterns of the dominant taxonomic and functional groups decreased in diversity, with the greatest decreases in biomass of Bacillariophyceae and group D (mainly the diatom Stephanodiscus hantzschii), and coincided with the introduction of group H1 (dinitrogen-fixing nostocaleans). The potential drivers for these changes were precipitation, water level, and total nitrogen (TN) for taxonomic groups and TN, total phosphorus, and euphotic zone depth for functional groups. The results of the MARSS model and temporal trends for each driver indicated that the increases in the water level and light availability were mostly related with the taxonomic and functional groups, respectively. The model for functional groups proposed a total of 24 significant inter-group relationships, where five relationships supported the succession patterns of dominant groups in the Nakdong River. Combined with the effects of increased light availability, a positive relationship between groups H1 and M (mainly Cyanobacteria and Microcystis aeruginosa) appears to induce cyanobacterial bloom development over a long period. These results can be fundamental information for river system management concerning the resulting cascading effects of changes in environmental drivers and inter-group relationships on the phytoplankton community composition.

An Hetero-Epitaxially Grown Zeolite Membrane.

The secondary growth methodology to form zeolite membranes has stringent requirements for homogeneous epitaxial intergrowth of the seed layer and limits the number of accessible high-quality zeolite membranes. Despite previous reports on hetero-epitaxial growth, high-performance zeolite membranes have yet to be reported using this approach. Here, the successful hetero-epitaxial growth of highly siliceous ZSM-58 (DDR-type zeolite) films from a SSZ-13 (CHA-type zeolite) seed layer is reported. The resulting membranes show excellent CO2 perm-selectivities, having maximum CO2 /N2 and CO2 /CH4 separation factors (SFs) as high as about 17 and 279, respectively, at 30 °C. Furthermore, the hybrid membrane maintains the CO2 perm-selectivity in the presence of water vapor (the third main component in both cases), that is, CO2 /N2 SF of about 14 and CO2 /CH4 SF of about 78, respectively, at 50 °C (a representative temperature of both CO2 -containing streams).

Chabazite-Type Zeolite Membranes for Effective CO2 Separation: The Role of Hydrophobicity and Defect Structure.

Chabazite (CHA)-type zeolites are promising for the separation of CO2 from larger molecules, such as N2 (relevant to postcombustion carbon capture) and CH4 (relevant to natural gas/biogas upgrading). In particular, the pore size of CHA zeolites (0.37 × 0.42 nm2) can recognize slight molecular size differences between CO2 (0.33 nm) and the larger N2 (0.364 nm) or CH4 (0.38 nm) molecules, thus allowing separation in favor of CO2 through CHA membranes. Furthermore, the siliceous constituents in the CHA zeolite can reduce the adsorption capacity toward the smaller H2O molecule (0.265 nm) and, thus, the H2O permeation rate. This is highly desirable for securing good molecular sieving ability with CO2 permselectivity in the presence of H2O vapor. Indeed, a siliceous CHA film obtained with a nominal Si/Al ratio of 100 (CHA_100) showed high CO2/N2 and CO2/CH4 separation performance, especially in the presence of H2O vapor; ∼13.4 CO2/N2 and ∼37 CO2/CH4 separation factors (SFs) at 30 °C. These SFs were higher than the corresponding values (∼5.2 CO2/CH4 SFs and ∼31 CO2/CH4 SFs) under dry conditions; such improvement could be ascribed to defect blocking by physisorbed water molecules. Finally, the contribution of molecular transport through zeolitic and nonzeolitic parts was quantitatively analyzed by combining information extracted from image processing of fluorescence confocal optical microscopy images with a one-dimensional permeation model. It appears that ∼19 and ∼20% of the total CO2 permeance for CHA_100 were reduced due to transport inhibition by the physisorbed water molecules on the membrane surface and defect, respectively.

Complete mitochondrial genome of the freshwater bryozoan Pectinatella magnifica (Phylactolaemata: Plumatellida) assembled from next-generation sequencing data.

The complete mitochondrial genome of the freshwater bryozoan Pectinatella magnifica was sequenced. The circular mitochondrial genome is 17,539 bp and consists of 13 protein-coding, two ribosomal RNA, and 22 transfer RNA genes (GenBank accession no. MG546680). The Bayesian comparative analysis of molecular evolution rates revealed no acceleration of the mitochondrial DNA (mtDNA) evolution of P. magnifica. Results of maximum likelihood analysis showed that this species clustered with other species of the phylum Bryozoa.

Extremely low-frequency electromagnetic field induces neural differentiation of hBM-MSCs through regulation of (Zn)-metallothionein-3.

Extremely low-frequency electromagnetic field (ELFEMF) can stimulate neural differentiation in human bone marrow-derived mesenchymal cells (hBM-MSCs), and this provides an opportunity for research on neurodegenerative diseases such as Alzheimer's disease (AD). Metallothionein-3 (MT3), an isoform of the metal-binding proteins, metallothioneins, involved in maintaining intracellular zinc (Zn) homeostasis and the deregulation of zinc homeostasis, has separately been implicated in AD. Here, we investigated the effect of ELFEMF-induced neural differentiation of hBM-MSCs on Zn-MT3 homeostatic interaction. Exposure to ELFEMF induced neural differentiation of hBM-MSCs, which was characterized by decreased proliferation and enhanced neural-like morphology. We observed expression of neuronal markers such as ß-tubulin3, pleiotrophin, and neurofilament-M at the mRNA level and MAP2 at the protein level. ELFEMF-induced neural differentiation correlated with decreased expression of metal-response element-transcription factor 1 and MT3, as well as decreased intracellular Zn concentration. In addition, upregulation of dihydropyrimidinase-related protein 2 was observed, but there was no change in γ-enolase expression. These data indicate a possible regulatory mechanism for MT3 during neural differentiation. Our findings provide considerable insight into molecular mechanisms involved in neural differentiation, which is useful for developing new treatments for neurodegenerative diseases. Bioelectromagnetics. 38:364-373, 2017. © 2017 Wiley Periodicals, Inc.

High-risk drinking is associated with a higher risk of diabetes mellitus in Korean men, based on the 2010-2012 KNHANES.

We examined the association between alcohol-drinking pattern and diabetes mellitus (DM) in Korean adults. This cross-sectional study included 12,486 participants (5551 men and 6935 women) who participated in the 2010-2012 Korean National Health and Nutrition Examination Survey. We categorized alcohol-drinking pattern into three groups based on the alcohol-use disorders identification test (AUDIT): low-risk (score: 0-7), intermediate-risk (score: 8-14), and high-risk (score: ≥15). DM was defined as having fasting plasma glucose ≥126 mg/dL or taking glucose-lowering medication, including insulin therapy. In the study population, 25.2% of men and 4.7% of women were high-risk drinkers. DM prevalence was 9.2% in men and 5.4% in women. DM prevalence was 9.0% and 5.7% in the low-risk drinking group, 7.6% and 4.1% in the intermediate-risk drinking group, and 11.2% and 3.5% in the high-risk drinking group in men and women, respectively. Compared to the low-risk drinking group, odds ratios (95% confidence intervals) of men and women in the intermediate-risk drinking group for DM were 1.043 (0.779-1.396) and 1.139 (0.712-1.824), respectively, and 1.480 (1.133-1.933) and 0.827 (0.296-2.311) in the high-risk drinking group, after adjusting for age and other confounding factors. In conclusion, high-risk drinking appears to be associated with a higher risk of DM in men, but not in women.

NF-kappaB Activation by compounds found in Platycodon grandiflorum extract.

Compounds extracted from Platycodon grandiflorum were evaluated for an activation effect on nuclear factor-kappa B (NF-kappaB). In its active state, NF-kappaB turns on the expression of genes related to cell proliferation or death. NF-kappaB activators promote growth of neuron cells and can be used to control neurodegenerative diseases. The biological activity of P. grandiflorum extracts toward NF-kappaB had not yet been studied. Although the biological activity of several compounds extracted from P. grandiflorum was evaluated, only three exhibited any significant activation effect on NF-kappaB.

Inhibitory effect against Akt of cyclic dipeptides isolated from Bacillus sp.

Among thirteen strains of the genus Bacillus isolated from Shrimp-jeotkal in our laboratory, a strain BA34 showing good antifungal activity against Phytophthora infestans in a previous experiment was tested for the inhibitory effect against Akt, protein kinase B. Since Akt is known to play an important role in controlling apoptosis, its inhibitors can be used as potential apoptosis-inducing agents in the treatment of cancer. Two active compounds were isolated and their structures were determined. They have similar structures, despite showing different inhibitory effects. In order to elucidate the reasons for these different effects, three-dimensional studies were carried out.

Microorganisms against Plasmodiophora brassicae.

In order to find microorganisms showing antifungal activities against Plasmodiophora brassicae, which causes club root, Korean salt-fermented fishery products were tested. Several fermented broths of microorgansims isolated from Ammodytes personatus fishery products showed high antifungal activities. The identification of microorganisms and their in vivo antifungal activities are reported herein.

CACTA and MITE transposon distributions on a genetic map of rice using F15 RILs derived from Milyang 23 and Gihobyeo hybrids.

Up to 35% of the rice genome consists of various kinds of transposons, and CACTA and MITE are two of the major class 2 DNA transposons in the genome. We have employed the consensus sequences of Rim2/Hipa CACTA, Stowaway MITE Pangrangja, and Tourist MITE Ditto for transposon display (TD) analysis to locate them on a genetic map, with 58 SSR markers used to anchor them. The TD analysis produced a high profile of the polymorphisms between the parental lines, Oryza sativa var. Gihobyeo/O. sativa var. Milyang, in intraspecific F15 RIL lines, locating 368 markers of Rim2/Hipa CACTA, 78 markers of Tourist MITE Ditto, and 22 markers of Stowaway MITE Pangrangja. In the segregation analysis, non-parental segregating bands and segregation distortion bands were observed. The recombinant genetic map spans 3023.9 cM, with 5.7 cM the average distance between markers. The TD markers were distributed unequally on the chromosomes because many TD markers were located in pericentric chromosomal regions except in the cases of chromosomes 2, 3, 6 and 9. Although the number of transposon markers was not sufficient to include all rice class 2 transposons, the current map of CACTA and MITE transposons should provide new insight into the genome organization of rice since no previous DNA transposon map is available.

Genetic diversity and phylogenetic relationship in AA Oryza species as revealed by Rim2/Hipa CACTA transposon display.

CACTA is a class 2 transposon, that is very abundantly present in plant genomes. Using Rim2/Hipa CACTA transposon display (hereafter Rim2/Hipa-TD), we analyzed several A-genome diploid Oryza species that have a high distribution of the CACTA motifs. High levels of polymorphism were detected within and between the Oryza species. The African taxa, O. glaberrima and O. barthii, both showed lower levels of polymorphism than the Asian taxa, O. sativa, O. rufipogon, and O. nivara. However, O. longistaminata, another African taxon, showed levels of polymorphism that were similar to the Asian taxa. The Latin American taxon, O. glumaepatula, and the Australian taxon, O. meridionalis, exhibited intermediate levels of polymorphism between those of the Asian and African taxa. The lowest level of polymorphism was observed in O. glaberrima (32.1%) and the highest level of polymorphism was observed in O. rufipogon (95.7%). The phylogenetic tree revealed three major groups at the genetic similarity level of 0.409. The first group consisted of three Asian taxa, O. sativa, O. rufipogon and O. nivara. The second group consisted of three African taxa, O. glaberrima, O. barthii, O. longistaminata, and an American taxon, O. glumaepatula. The third group contained an Australian taxon, O. meridionalis. The clustering patterns of these species matched well with their geographical origins. Rim2/Hipa-TD appears to be a useful marker system for studying the genetic diversity and species relationships among the AA diploid Oryza species.

Increased aquaporin-1 expression in choroid plexus epithelium after systemic hyponatremia.

The expression of aquaporin-1 (AQP1) protein, a water channel, in the choroid plexus epithelium was examined in the rat to determine the role of AQP1 in the pathophysiology of systemic hyponatremia. Systemic hyponatremia was produced by coadministration of 30 ml hypotonic dextrose solution (140 mM) intraperitoneally and 3 microg 1-deamino-8-d-arginine vasopressin (dDAVP) subcutaneously. This hydration protocol produced severe systemic hyponatremia: 2h after drug administration, normonatremic serum osmolarity and Na(+) concentration (296+/-5mOsm/L and 140+/-5 mM) were reduced to 252+/-5mOsm/L and 117+/-2 mM, respectively. AQP1 expression in the third ventricle choroid plexus epithelium was determined by using immunohistochemistry and quantitative immunoblot analysis. After 2h of systemic hyponatremia, AQP1 expression was significantly increased by 28.2+/-2.7% (n=6, P<0.05), whereas it was attenuated to 15.7+/-2.2% (n=6, P<0.05) after 6h of systemic hyponatremia. In addition, TUNEL staining revealed apoptotic granule cells in the dentate gyrus (DG) adjacent to the third ventricle with a peak measured 2h after the start of the systemic hyponatremia protocol, while virtually no apoptotic granule cells left 6h after the start of the hyponatremic treatment. These findings suggest that AQP1-mediated excessive water influx into the brain through the blood-cerebrospinal fluid barrier during systemic hyponatremia may elevate the intracranial pressure and result in the apoptotic brain cell death. Thus, AQP1 in the choroid plexus may play an important role in the pathogenesis of systemic hyponatremia.

Isolation of callus-specific mRNAs from differentiating embryogenic somatic calli of Pimpinella brachycarpa by cDNA-AFLP.

We used cDNA-AFLP to analyze gene expression profiles during somatic embryogenesis and to isolate stage-specific genes in Pimpinella brachycarpa. Ninety-six combinations of AFLP primers produced 3,785 fragments, of which 478, 403, and 436 were specific to calli, somatic embryos, and plants, respectively. 262 fragments were shared by callus and somatic embryo, 324 by somatic embryo and plant, and 222 by callus and plant. The number of fragments common to all three stages was 1,660. Seventy-five of the 478 callus-specific fragments were cloned and sequenced and their functions sought in the GenBank database. Thirty-three of them showed significant homology to GenBank data base entries and twelve of these were homologous to genes with products of known function such as ATPases, tubulins, kinases, transcription factors, ubiquitins, and ankyrin. Callus-specific expression was confirmed by performing RT-PCR with six of the twelve fragments. Since the somatic embryo is induced by auxin (Thidiazuron), possible down regulation of these genes by auxin is also discussed.