Phytoplankton assemblage responses to massive freshwater inputs and anthropogenic toxic substances contamination in the Geum River Estuary, South Korea.

This study investigated the relationships between phytoplankton assemblages and water contamination by persistent toxic substances (PTSs) and nutrients in an estuary with an artificial dam over one year. The distribution of PTSs, including 15 polycyclic aromatic hydrocarbons, 6 alkylphenols, and 8 metal(loid)s, along with nutrients, exhibited relatively high concentrations with irregular temporal fluctuations in the inner estuary. During winter and spring, phytoplankton communities showed good ecological quality, with an average of 28 species and a density of 1750 cells L-1. In contrast, during summer, there was a significant increase in the density of freshwater species (max 45,000 cells L-1). These assemblages were categorized into three seasonal groups, featuring dominant taxa like blue-green algae and diatoms. Temperature and nutrient levels were the principal factors influencing phytoplankton assemblages, while PTSs had a minor impact. Overall, phytoplankton assemblages displayed strong seasonal variation, mainly influenced by freshwater input and nutrient availability.

Cardioprotective polyphenols from Geum japonicum var. chinense.

Seven undescribed tannins, namely gejaponin A-G, and one dehydrodigallic acid derivative 3,4-dihydroxy-5-(3,4,5-trihydroxy-1-ethoxycarbonyl phenoxy)benzoic acid, together with eighteen known polyphenols were isolated from the 95% ethanol extract of the aerial part of Geum japonicum Thunb. var. chinense F. Bolle. Their structures were elucidated on the basis of comprehensive analysis of UV, IR, NMR, HRMS, and CD spectroscopy experiments. To evaluate their bioactivities, sixteen major compounds were selected to intervene in hydrogen peroxide (H2O2)-induced oxidative damage on H9c2 rat cardiomyoblasts. Some compounds demonstrated high activity in this assay, of which, the known compounds 16 and 21 exhibited strong protective effects against H2O2-induced injury in H9c2 rat cardiomyoblasts, with a comparable cardioprotective activity as that of the positive control trimetazidine, thereby revealing cardioprotective activities from G. japonicum var. chinense.

Comparative complete chloroplast genome of Geum japonicum: evolution and phylogenetic analysis.

Geum japonicum (Rosaceae) has been widely used in China as a traditional herbal medicine due to its high economic and medicinal value. However, the appearance of Geum species is relatively similar, making identification difficult by conventional phenotypic methods, and the studies of genomics and species evolution are lacking. To better distinguish the medicinal varieties and fill this gap, we carried out relevant research on the chloroplast genome of G. japonicum. Results show a typical quadripartite structure of the chloroplast genome of G. japonicum with a length of 156,042 bp. There are totally 131 unique genes in the genome, including 87 protein-coding genes, 36 tRNA genes, and 8 rRNA genes, and there were also 87 SSRs identified and mostly mononucleotide Adenine-Thymine. We next compared the plastid genomes among four Geum species and obtained 14 hypervariable regions, including ndhF, psbE, trnG-UCC, ccsA, trnQ-UUG, rps16, psbK, trnL-UAA, ycf1, ndhD, atpA, petN, rps14, and trnK-UUU. Phylogenetic analysis revealed that G. japonicum is most closely related to Geum aleppicum, and possibly has some evolutionary relatedness with an ancient relic plant Taihangia rupestris. This research enriched the genome resources and provided fundamental insights for evolutionary studies and the phylogeny of Geum.

Spatial investigation of water quality and estimation of groundwater pollution along the main stream in the Geum River Basin, Korea.

This study aims to identify spatially water quality distribution of groundwater and surface water in reservoirs, and comprehensively to address possible influencing factors. The concentration of NO3 in the reservoirs along the main stream of the Geum River was generally lower than that in groundwater. The pollution level of the reservoir, especially the particulate pollutant SS, clearly showed seasonal variations and increased significantly downstream. The H-3 concentration of the groundwater was high in the plains and low in the mountain areas, indicating a difference in residence time between the two regions. The hydrochemical properties and factor loading values of the principal components indicated that the major factors were water‒rock interactions and residence time, but a positive correlation of K-NO3 and Mg-Cl showed the influence of agricultural activities. The main groundwater pollutants were likely to be contributed by agricultural activities at upstream and seawater intrusion at downstream. The sensitive redox species uranium in the groundwater of this region existed as the uranyl ion, and it showed a positive correlation with HCO3, pH, and Ca. The results emphasize the importance of monitoring both tributaries and groundwater together in order to effectively manage the water quality of the Geum River basin.

LncRNA XIST protects podocyte from high glucose-induced cell injury in diabetic nephropathy by sponging miR-30 and regulating AVEN expression.

Diabetic nephropathy (DN) is one of the most important complications of diabetes mellitus. Thus, it is urgent to develop a novel diagnosis or therapeutic strategy that could suspend DN progression. Moreover, there is increasing evidence demonstrating that long non-coding RNA (lncRNA) acts as critical players in regulating autophagy and are involved in DN. We demonstrated that lncRNA X-inactive specific transcript (XIST) was downregulated in high glucose (HG) treated podocytes, accompanied by increased apoptosis of podocytes. Overexpression of XIST significantly reduced the apoptosis and promoted the number of viable cells of podocyte under HG treatment. Prediction by Targets can and dual-luciferase reporter assay revealed the interaction between miR-30 and XIST and AVEN. Further WB (Western Blot), MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), and flow cytometry confirmed that XIST could reverse the expression of AVEN and ameliorate HG-induced apoptosis. In conclusion, our research revealed that XIST plays a protective effect on podocyte injury induced by HG through miR-30/AVEN axis.

The Impact Evaluation of Acid Mine Drainage on Zebrafish (Danio rerio) and Water Fleas (Daphnia magna) in the Vicinity of the Geum River Basin in Korea.

Heavy metals, such as copper, lead, and cadmium, carried by acid mine drainage are pollutants of the aquatic ecosystem, posing a significant health risk to the water resource for humans. Environmental technologies to reduce metal contamination are applied for post-mining prevention and improvement. Despite detailed pollution management, water contaminated by heavy metals still flows into the natural water system. This study investigated the impact of drainage discharged from abandoned mines near the major river in South Korea on aquatic organisms. The toxicity of the field water showed a more significant effect than observed through the experiment for each heavy-metal concentration. Various toxic substances coexisted in the field water around the mine, such that the overall toxic intensity was high even when the concentration of each heavy metal was low. As a result, the inhibition of activity of aquatic organisms was observed at low individual concentrations, and further investigation on the effect of long-term exposure to trace amounts of heavy metals is required.

Environmental contributions to the evolution of trait differences in Geum triflorum: Implications for restoration.

PREMISE: How the environment influences the distribution of trait variation across a species' range has important implications for seed transfer during restoration. Evolution across environments could influence fitness when individuals are transferred into new environments. Here, we evaluate the role the environment has had on the distribution of genetic variance for traits important to adaptation. METHODS: In a common garden experiment, we quantified trait differentiation for populations of Geum triflorum sourced from three distinct ecoregions and evaluated the ability of climate to predict trait variation. Populations were sourced from the Manitoba and Great Lake alvar ecoregions that experience predictable extremes in seasonal water availability and the prairie ecoregion which exhibits unpredictable changes in water availability. RESULTS: Plants sourced from alvar ecoregions exhibited smaller but more stomata and greater intrinsic water-use efficiency relative to prairie plant populations, supporting the evolution of ecotypic differences. Estimates of standing genetic variance and heritable genetic variation for quantitative traits suggest alvar populations have greater adaptive potential. However, low evolvability suggests all populations likely have limited capacity to evolve in response to environmental change. CONCLUSIONS: These results highlight the importance of the environment in influencing the evolution and distribution of genetic differences across populations used as seed sources for restoration. Additionally, these data may inform recommendations for seed transfer across novel environments and our expectations of populations' adaptive potential.

Exploring the protective mechanisms of total tannins from Geum japonicum var. chinense F.Bolle in mice with hematopoietic dysfunction via the JAK2/STAT3/5 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Geum japonicum var. chinense F.Bolle (Rnglish name Gei herba, GH), a traditional Miao medicine, promotes hematopoiesis. Emerging evidence shows that total tannins of GH (TGH) can treat ischemic diseases. AIM OF THE STUDY: To explore the protective mechanism of TGH in hematopoietic dysfunction (HD) mice. MATERIALS AND METHOD: Forty-eight female mice were randomly assigned to 6 groups: control, model, Zhenqi Fuzheng positive, and three doses TGH. Cyclophosphamide was injected in mice to establish an HD model. Spleen tissue was examined histomorphologically, peripheral hemograms and organ index were calculated, and serum hematopoietic factor levels were determined. The expression of proteins in the Janus kinase 2 (JAK2)/transcription 3/5 (STAT3/5) pathway, as well as upstream and downstream proteins, was examined using western blot to elucidate the underlying protective mechanisms of TGH. RESULTS: TGH could effectively alleviate spleen tissue damage in HD mice, improve peripheral hemogram and antagonize organ atrophy, and increase levels of Granulocyte-macrophage Colony Stimulating Factor (GM-CSF) and Erythropoietin (EPO) in HD mouse serum. Furthermore, after TGH treatment, the protein expression levels of P-JAK2, P-STAT3, P-STAT5, M-CSF, G-CSF, Bcl-2, and Bcl-xL were significantly higher than in the model group. At the same time, following TGH treatment, the protein expression levels of LC3 A/B, Beclin1, ATG5, and ATG7 were significantly lower than in the model group. CONCLUSIONS: TGH has been shown to protect HD mice through a mechanism linked to the activation of the JAK2/STAT3/5 pathway, as well as autophagy inhibition and apoptosis activation.

Characterization of the complete mitogenome of the endangered freshwater fish Gobiobotia naktongensis from the Geum River in South Korea: evidence of stream connection with the Paleo-Huanghe.

BACKGROUND: The freshwater fish Gobiobotia naktongensis (Teleostei, Cypriniformes, and Gobionidae) is an endangered class I species whose population size has been greatly reduced. OBJECTIVE: To successfully protect and restore the highly endangered freshwater fish G. naktongensis from the Geum River in South Korea. METHODS: The mitogenome was characterized using the primer walking method with phylogenetic relationships. RESULTS: The complete mitogenome of G. naktongensis Geum River was 16,607 bp, comprising 13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA (tRNA) genes. Seventeen substitutions were found by comparing the tRNA regions between G. naktongensis Geum and Nakdong Rivers and G. pappenheimi; most were specific to G. naktongensis Nakdong River, with changes in their secondary structures. The comparison between G. naktongensis Geum River and G. pappenheimi revealed differences in the lengths of the D-loop and two tRNAs (tRNAArg and tRNATrp) and the secondary structures in the TΨC-arm of tRNAHis. In the phylogenetic tree, G. naktongensis Geum River did not cluster with its conspecific specimen from the Nakdong River in South Korea, but showed the closest relationship to G. pappenheimi in mainland China. CONCLUSIONS: Our results support the existence of the Paleo-Huanghe River connecting the Korean peninsula and mainland China, suggesting that G. naktongensis in the Geum River should be treated as a different evolutionarily significant unit separated from that in the Nakdong River. The complete mitogenome of G. naktongensis Geum River provides essential baseline data to establish strategies for its conservation and restoration.

Different effects of warming treatments in forests versus hedgerows on the understorey plant Geum urbanum.

The effectiveness of hedgerows as functional corridors in the face of climate warming has been little researched. Here we investigated the effects of warming temperatures on plant performance and population growth of Geum urbanum in forests versus hedgerows in two European temperate regions. Adult individuals were transplanted in three forest-hedgerow pairs in each of two different latitudes, and an experimental warming treatment using open-top chambers was used in a full factorial design. Plant performance was analysed using mixed models and population performance was analysed using Integral Projection Models and elasticity analyses. Temperature increases due to open-top chamber installation were higher in forests than in hedgerows. In forests, the warming treatment had a significant negative effect on the population growth rate of G. urbanum. In contrast, no significant effect of the warming treatment on population dynamics was detected in hedgerows. Overall, the highest population growth rates were found in the forest control sites, which was driven by a higher fecundity rather than a higher survival probability. Effects of warming treatments on G. urbanum population growth rates differed between forests and hedgerows. In forests, warming treatments negatively affected population growth, but not in hedgerows. This could be a consequence of the overall lower warming achieved in hedgerows. We conclude that maintenance of cooler forest microclimates coul, at least temporarily, moderate the species response to climate warming.

Environmental fate and trophic transfer of synthetic musk compounds and siloxanes in Geum River, Korea: Compound-specific nitrogen isotope analysis of amino acids for accurate trophic position estimation.

Despite the extensive usage of synthetic musk compounds (SMCs) and siloxanes in various personal care products (PCPs), trophic magnification of such chemicals in aquatic environments remains unexplored. In June and September 2020, eleven SMCs and nineteen siloxanes were measured in water, sediments, and biota. Samples were collected from two sites where levels were expected to be influenced by the distance from the wastewater treatment plant (WWTP) in the Geum River, Republic of Korea, were expected. High concentrations of SMCs and siloxanes entered through WWTP were measured in water, sediment, and biota at the both sites and both seasons. The δ15N of amino acids provided a high-resolution food web and accurate trophic position (TP), which is an important factor for determining the trophic magnification factor (TMF). Among 24 TMFs, 19 of them were <1, ranging 0.7-0.8 for 1,3,4,6,7,8­hexahydro­4,6,6,7,8,8­hexamethyl­cyclopenta­Î³­2­benzopyran (HHCB), 0.6-0.8 for 6-Acetyl-1,1,2,4,4,7-hexamethyltetralin (AHTN), 0.7-0.8 for 4-tert-Butyl-3,5-dinitro-2,6-dimethylacetophenone (MK), 0.7-0.9 for octamethylcyclotetrasiloxane (D4), 0.1-0.4 for decamethylcyclopentasiloxane (D5), and 0.04-0.8 for dodecamethylcyclohexasiloxane (D6), and the remaining ones including HHCB, AHTN, MK, and D4 showed values close to 1 or slightly higher (TMF range: 1.0-2.3) indicating no or a little trophic magnification. The TMFs of these compounds were constant across sites and seasons. The TMF values of PCPs might be affected by species specificity and food web structure rather than by chemical properties such as log Kow, which describes a wide range of TMF values in various environments. This study presents valuable implications for assessing risk and managing environmental fate and trophic transfer of SMCs and siloxanes in freshwater environments.

Evaluation of Geum urbanum L. Extracts with Respect to Their Antimicrobial Potential.

Preparations derived from roots and rhizomes of Geum urbanum L. are traditionally used for the treatment of ulcers and irritations of mucous membranes of the mouth, stomach, and intestinal tract. In complementary medicine, fermentation is one of the methods applied to recover plant extracts used for the production of such pharmaceutical preparations. The present study was performed to characterize the secondary metabolites and to evaluate the antimicrobial potential of different G. urbanum root and rhizome extracts. For this purpose, individual metabolites of fresh and fermented G. urbanum root and rhizome extracts were analyzed by HPLC-DAD-MSn and GC/MS. Among others, rare ellagitannin-sulfates could be characterized by LC/MSn . In addition, the antibacterial activity of various extracts of fresh and dried G. urbanum roots and rhizomes against Staphylococcus aureus (ATCC 6538) and Cutibacterium acnes (CP033842.1; FDAARGOS 503 chromosome) were assessed and compared to that of G. rivale. Furthermore, low- and high-molecular tannins were fractionated by column chromatography, demonstrating the latter to exhibit highest antibacterial activity.

Slight dependence of temperate-forest herbaceous plants, Geum urbanum and Senecio ovatus, on arbuscular mycorrhizal fungi (AMF) enables them to colonise soils with a low level of AMF abundance.

While numerous studies have revealed that arbuscular mycorrhizal fungi (AMF) enhance plant performance, the influence of these symbionts on temperate-forest herbaceous species in relation to soil physical and chemical properties has been left largely unexplored. Therefore, two perennial herbs, Geum urbanum (Rosaceae) and Senecio ovatus (Asteraceae), were examined in a laboratory pot experiment to determine whether AMF influenced their growth, photosynthetic performance index, and N and P contents in biomass. The treatments, involving three widespread AMF species, were prepared in the soils of two habitats colonised by both plants, namely beech and riparian forests, as follows: (1) control-soils without AMF, (2) Claroideoglomus claroideum, (3) Funneliformis geosporus, and (4) Funneliformis mosseae. Neither shoot mass nor photosynthetic performance index of G. urbanum and S. ovatus was enhanced by AMF. Senecio ovatus root mass was increased compared to control only by F. geosporus. Inconsistent effects were observed in N and P contents in shoots and roots of both species. The direction and magnitude of these responses were dependent on the fungal species and soil type. Although the plant species belong to families whose representatives are usually regularly colonised by and highly responsive to AMF, our study indicates that AMF had only a slight impact on the performance of G. urbanum and S. ovatus at the early stages of their development. The plants being slightly dependent on AMF are thus adapted to colonise temperate-forest soils with a low level of availability of AMF propagules.

Multimedia distributions and the fate of microcystins from freshwater discharge in the Geum River Estuary, South Korea: Applicability of POCIS for monitoring of microalgal biotoxins.

Here, we investigated the characteristics of the environmental multimedia distribution of microcystins (MCs) introduced from freshwater discharge through the estuary dam of the Geum River. In addition, the applicability of a passive sampling device (polar organic chemical integrative sampler, POCIS) for monitoring MCs was evaluated. Surface water, suspended solids (SS), sediments, and oysters were collected from the inner and outer estuary dam. Seven MC variants were analyzed using HPLC-MS/MS. POCIS was deployed at three sites over one week, and MCs were monitored for four weeks from August to September 2019. Before POCIS was deployed in the field, compounds-specific sampling rates of MCs were determined as functions of water temperature (10, 20, and 30 °C), flow rate (0, 0.38, and 0.76 m s-1), and salinity (0, 15, and 30 psu) in the laboratory. The sampling rates of MCs in POCIS increased significantly with increasing water temperature and flow rate, whereas salinity did not significantly affect the sampling rates between freshwater and saltwater. The MCs in the Geum River Estuary mainly existed as particulate forms (mean: 78%), with relatively low proportions of dissolved forms (mean: 22%), indicating that MCs were mainly contained in cyanobacterial cells. There was no significant correlation among the concentrations of MCs in water, SS, sediments, and oysters. Time-weighted average concentrations of MCs from POCIS were not significantly correlated with the concentrations of MCs in water and oysters. The metabolites of MCs, including MC-LR-GSH, MC-LR-Cys, MC-RR-GSH, and MC-RR-Cys, were detected in oysters (no metabolites were detected in POCIS). Overall, POCIS can be useful for monitoring dissolved MCs in the aquatic ecosystem, particularly in calculating time-weighted average concentrations, but it seems to have limitations in evaluating the contamination status of total MCs, mainly in particulate form.

Long-term environmental changes in the Geum Estuary (South Korea): Implications of river impoundments.

We investigated a sediment core collected from the Geum Estuary through sedimentological and geochemical analyses. Three lithological units were classified based on sedimentological characteristics. Unit 1 and Unit 3 were geochemically distinct, while Unit 2 was the transitional phase between them. The geochemical results suggest that the contribution of terrestrial organic carbon (OC) to the sedimentary OC pool in the coarse-grained Unit 1 was lesser than that of fine-grained Unit 3. The excess activity (210Pbex) and the sedimentation rate indicate that Unit 1 corresponded to 1977 Common Era (CE). Since the first dam construction on the Geum River began in 1975 CE, the deposition of Unit 1 in the Geum Estuary is likely associated with river impoundments, which reduce the delivery of fine-grained sediment and terrestrial OC to the estuary. This study highlights the role of river impoundments in altering the sedimentary OC and thus the sedimentary environment in the estuary.

In Vitro Antineoplastic and Antiviral Activity and In Vivo Toxicity of Geum urbanum L. Extracts.

This study evaluated the in vitro antineoplastic and antiviral potential and in vivo toxicity of twelve extracts with different polarity obtained from the herbaceous perennial plant Geum urbanum L. (Rosaceae). In vitro cytotoxicity was determined by ISO 10993-5/2009 on bladder cancer, (T-24 and BC-3C), liver carcinoma (HEP-G2) and normal embryonic kidney (HEK-293) cell lines. The antineoplastic activity was elucidated through assays of cell clonogenicity, apoptosis induction, nuclear factor kappa B p65 (NFκB p65) activation and total glutathione levels. Neutral red uptake study was applied for antiviral activity. The most promising G. urbanum extract was analyzed by UHPLC-HRMS. The acute in vivo toxicity analysis was carried out following OEDC 423. The ethyl acetate extract of aerial parts (EtOAc-AP) exhibited the strongest antineoplastic activity on bladder cancer cell lines (IC50 = 21.33-25.28 µg/mL) by inducing apoptosis and inhibiting NFκB p65 and cell clonogenicity. EtOAc and n-butanol extracts showed moderate antiviral activity against human adenovirus type 5 and human simplex virus type I. Seventy four secondary metabolites (gallic and ellagic acid derivatives, phenolic acids, flavonoids, etc.) were identified in EtOAc-AP by UHPLC-HRMS. This extract induced no signs of acute toxicity in liver and kidney specimens of H-albino mice in doses up to 210 mg/kg. In conclusion, our study contributes substantially to the detailed pharmacological characterization of G. urbanum, thus helping the development of health-promoting phytopreparations.

Distribution of microcystins in environmental multimedia and their bioaccumulation characteristics in marine benthic organisms in the Geum River Estuary, South Korea.

Spatio-temporal distributions and bioaccumulation characteristics of freshwater cyanobacterial toxins, such as microcystins (MCs) in the Geum River Estuary, South Korea, were investigated during summer. Environmental multimedia samples (water, suspended particulate matter (SPM), and sediments) and tidal flat organisms (polychaetes, decapods, amphipods, and bivalves) were collected from regions inside and outside of the estuary dam for MCs analysis. Phytoplankton communities in the Geum River (freshwater) and estuarine area (brackish water) were also analyzed in order to understand the relationship with MCs concentrations. Seasonal variation in the structure of phytoplankton communities was detected in the Geum River, with a relatively high density of Cyanophyta in summer. MC concentrations were strongly correlated to water temperature, chlorophyll a, and cyanobacterial density. MC-LR was the most abundant MC variants in environmental samples. Dissolved MCs remained for longer periods and were more widely distributed in the coastal environments compared to particulate MCs. The distribution coefficients between water and SPM (Kd-SPM) and between water and sediments (Kd-sediment) of MCs showed that the phase shift of MCs in the environmental samples occurred in the estuary. Kd-SPM declined from the inside to outside regions of the estuary dam, and was mainly attributed to differences in the half-lives of MCs in dissolved (4.7 d for MC-LR) and particulate phases (0.44-0.52 d for MC-LR). Species-specific bioaccumulation of MCs occurred in tidal flat organisms, with relatively high bioaccumulation factors of MCs being detected in polychaetes and decapods compared to amphipods and bivalves. Overall, this study advances our understanding on the distribution, transport, fate, and bioaccumulation of MCs in estuarine and coastal environments.

Macrozoobenthic community responses to sedimentary contaminations by anthropogenic toxic substances in the Geum River Estuary, South Korea.

We investigated the sedimentary pollution by persistent toxic substances (PTSs) and their potential impacts on the macrobenthic faunal community in the Geum River Estuary, South Korea. Sediment and benthic macrofauna samples were collected from eight sites every two months during the period of February to December in 2015. Target PTSs encompassed metals (Cd, Cr, Cu, Hg, Ni, Pb, and Zn), one metalloid (As), polycyclic aromatic hydrocarbons (PAHs), and alkylphenols (APs). The significant difference to the environment of the inner and outer parts of the estuary (p < 0.05) was found with relatively high concentrations of PTSs in sediment from the inner estuary. The concentrations of Cu and Zn exceeded the sediment quality guidelines of Korea representing a potential risk to aquatic organisms. The primary source of PAHs was by-products of diesel and gasoline combustion (37%), followed by a coke oven (32%) and oil-burning (31%). The macrofaunal community was spatially distinguished between the inner and outer parts of the estuary (p < 0.05), regardless of the season. In the inner part of the estuary, the density of the macrofaunal community was high, due to the increased opportunistic species and/or some indicator species (organic polluted or enrichment), implying that the given environment was disturbed. Among the environmental parameters analyzed by the distance-based linear model (DistLM), salinity, chlorophyll-a, and nutrient concentrations were found to be key factors controlling the changes in macrofaunal community structure. Such changes in the closed estuary system would indicate that each taxonomic group had to adjust to lower salinities and alternative food sources. Overall, the distribution of PTSs and macrozoobenthic communities in the Geum River Estuary collectively reflected the environmental gradients caused by surrounding activities in the inner part of the estuary together with direct effects by the irregular inflow of freshwater.

Seasonal contrast of particulate organic carbon (POC) characteristics in the Geum and Seomjin estuary systems (South Korea) revealed by carbon isotope (δ13C and Δ14C) analyses.

In this study, we newly investigated surface water samples collected in two contrasting Korean estuary systems (i.e., closed Geum and open Seomjin estuaries) along a salinity gradient in winter (December) in 2016. The main objectives were to determine the source of particulate organic carbon (POC) in winter and to assess the environmental factors inducing seasonal differences in POC characteristics. Concentrations and dual carbon isotopes (δ13C and Δ14C) of POC were analyzed together with concentrations and stable carbon isotopes (δ13C) of dissolved inorganic carbon (DIC) and compared with those obtained in summer (August) in 2016. Our study provided a new insight that for both estuarine systems, the seasonal contrast in POC characteristics was associated with stronger wind-induced estuarine sediment resuspensions in winter than in summer providing a greater contribution of aged POC to the total POC pool in winter.

Protection of the Geum japonicum Thunb. var. chinense extracts against oxygen-glucose deprivation and re-oxygenation induced astrocytes injury via BDNF/PI3K/Akt/CREB pathway.

Geum japonicum Tunb. var. chinense (GJ) is a traditional Chinese medicine usually used for the alleviation of dizziness and headache. Previous studies have reported that the GJ extracts could alleviate cerebral I/R injury by reducing apoptosis in vivo. To further elucidate the positive role and underlying mechanism of the GJ extracts in cerebral I/R injury, the current study investigated the effects of the GJ extracts on oxygen-glucose deprivation and re-oxygenation (OGD/R)-induced astrocytes injury in light of BDNF/PI3K/Akt/CREB signaling pathway with seropharmacological method. In the present study, the LC-MS profiling of the GJ extracts, obtain by reflux extraction, led to the identification of three possible active components were 5-desgalloylstachyurin, tellimagrandin II (TG II) and 3,4,5-Trihydroxybenzaldehyde (THBA). Drug-containing serum was collected from rats given different doses of the GJ extracts (0, 1.75 g/kg, 7 g/kg). Data indicated that the GJ extracts could increase the cell viability and decrease apoptosis and the expression of glial fibrillary acidic protein (GFAP) in OGD/R-induced astrocytes. In addition, the detection of apoptosis-related factors showed that the GJ extracts could obviously increase the expression of Bcl-2 and reduce the expression of Bax, Caspase-3 and cleaved-Caspase-3. Furthermore, the GJ extracts markedly increased the expression of BDNF, TrkB, PI3K, p-Akt and p-CREB. All these effects of the GJ extracts could be significantly reversed by LY294002, an inhibitor of PI3K. These data indicated that the GJ extracts could protect astrocytes against OGD/R-induced injury by inhibiting astrocytes reactivity and apoptosis, owing to the activation of the BDNF/PI3K/Akt/CREB pathway. The results support the application of the GJ extracts in the treatment of ischemic stroke and other ischemic encephalopathy.