Dissolved trace elements in the Ganges-Brahmaputra-Meghna River Basin: A new approach for estimating trace element flux inputs from rivers into the world's oceans.

Understanding the changes in the chemical compositions of dissolved trace elements from source to sink is important for determining their spatiotemporal variations and the contributions from each sub-catchment in the Ganges, Brahmaputra, and Meghna Rivers. To estimate weathering and matter transfer in these Rivers and the Ganges-Brahmaputra-Meghna (G-B-M) Estuary, we measured 15 dissolved trace element concentrations from surface and bottom water samples and exchangeable trace metals from suspended particulate matter (SPM). From December 2019 to January 2020, post-monsoon samples were collected from the upstream of the three rivers and the G-B-M Estuary. Dissolved trace elements in the Ganges and Meghna Rivers exhibited remarkable spatial variations, whereas those in the Brahmaputra River and the G-B-M Estuary were uniform. The dissolved trace elements, basic information (river length and drainage area), and physicochemical parameters (pH, dissolved oxygen, and conductivity) of the three rivers were inconsistent. The sample sites near urban areas and industrial centers had high concentrations of dissolved trace elements. In the G-B-M Estuary, iron and lead concentrations decreased along the salinity gradient, whereas selenium levels gradually increased, which may have been released by the SPM owing to its highly exchangeable trace metals. Compared with historical concentrations, trace elements that entered the G-B Estuary from the Ganges and Brahmaputra Rivers exhibited either decreased or increased metal fluxes due to additional terrigenous sources, suggesting that the inputs of trace element flux from the Ganges and Brahmaputra Rivers into the oceans may need to be re-evaluated. Furthermore, Fe and Pb concentrations and river fluxes in the Ganges and Changjiang have decreased in recent years. Hence, the fluxes of certain trace elements that enter the oceans from large rivers may require re-evaluation.

Ginseng-DF ameliorates intestinal mucosal barrier injury and enhances immunity in immunosuppressed mice by regulating MAPK/NF-κB signaling pathways.

PURPOSE: Dietary fiber (DF) has a good application prospect in effectively restoring the integrity of the intestinal mucosal barrier. Ginseng-DF has good physicochemical properties and physiological activity and shows positive effects in enhancing immunity. The aim of this study was to investigate the protective effect of Ginseng-DF on intestinal mucosal barrier injury induced by cyclophosphamide (CTX) in immunosuppressed mice and its possible mechanism. METHODS: The effects of Gginseng-DF on immune function in mice were studied by delayed-type hypersensitivy, lymphocyte proliferation assay and NK cytotoxicity assay, the T lymphocyte differentiation and intestinal barrier integrity were analyzed by flow cytometry and western blot. RESULTS: Ginseng-DF (2.5% and 5%) could attenuate the inhibition of DTH response by CTX, promote the transformation and proliferation of lymphocytes, and stimulate NK effector cell activity. At the same time, Ginseng-DF could restore the proportion of CD4+/CD8+ T lymphocytes induced by CTX to different extents, improved spleen tissue damage, promoted the secretion of immunoglobulin IgG, and enhanced body immunity. More importantly, Ginseng-DF could up-regulate the contents of TNF-α, IFN-γ, IL-6 and IL-1ß in serum and intestine of immunosuppressed mice to maintain the balance between Th1/Th2 cytokines, and improve the permeability of intestinal mucosal barrier. Meanwhile, Ginseng-DF could reduce intestinal epithelial cell apoptosis and improve intestinal adaptive immunity in CTX-induced immunosuppressed mice by regulating MAPK/NF-κB signaling pathway. CONCLUSION: Ginseng-DF can be used as a safe dietary supplement to enhance body immunity and reduce intestinal mucosal injury caused by CTX.

Uptake and accumulation of di(2-ethylhexyl) phthalate (DEHP) in a soil-ginseng system and toxicological mechanisms on ginseng (Panax ginseng C.A. Meyer).

Di(2-ethylhexyl) phthalate (DEHP) is regarded as a priority environmental pollutant. This study explored the adsorption and accumulation of DEHP within the ginseng-soil system and the mechanism of DEHP toxicity to ginseng (Panax ginseng C.A. Meyer). Under exposure to 22.10 mg/kg DEHP in soil, DEHP mainly accumulated in ginseng leaves (20.28 mg/kg), stems (4.84 mg/kg) and roots (2.00 mg/kg) after 42 days. The oxidative damage, metabolism, protein express of ginseng were comprehensively measured and analyzed. The results revealed that MDA presented an activation trend in ginseng stems and leaves after 42 days of DEHP exposure, while the opposite trend was observed for POD. Levels of ginsenoside metabolites Rg2, Rg3, Rg5, Rd, Rf and CK decreased in the ginseng rhizosphere exudates under DEHP stress. Further investigations revealed that DEHP disrupts ginsenoside synthesis by inducing glycosyltransferase (GS) and squalene synthase (SS) protein interactions. Molecular docking indicated that DEHP could stably bind to GS and SS by intermolecular forces. These findings provide new information on the ecotoxicological effect of DEHP on ginseng root.

Nitrogen accumulation and attenuation in the Ganges-Brahmaputra-Meghna river system: An evaluation with multiple stable isotopes and microbiota.

We examined dissolved inorganic nitrogen (DIN) accumulation and attenuation in the lower stream and estuary of the Ganges-Brahmaputra-Meghna River system. In the lower stream of Ganges, Meghna and Brahmaputra rivers, nitrate (NO3-) was the dominant component in the DIN pool apart from the site near an industrial center. Concentrations of NO3- displayed minor differences between surface and bottom water, accounting for >90 % of the riverine DIN pool. Sources of NO3- were likely to be municipal wastewater and fertilizer based on signals of 15N-NO3- and 18O-NO3-. In the Meghna River, ammonium concentration in river water increased due to sewage discharge from local industrial centers. In the estuary, likely due to the high-abundance nitrifiers, nitrification rates overwhelmed removal rates and led to NO3- accumulation. Towards coastal ocean, DIN concentrations decreased due to seawater dilution and biological assimilation, indicating a tight linkage between the riverine input and ecological stability in the receiving water.

Comparison between three preconcentration resins to determine dissolved gallium in natural waters using isotope dilution and high resolution inductively coupled plasma mass spectrometry.

A new and accurate method using resin enrichment of Ga, combined with isotope dilution, was developed to determine its dissolved concentrations in natural waters. The extraction properties of Chelex-100, Nobias Chelate PA-1, and Presep® PolyChelate resins for Ga from river water and seawater were compared. Experiments were conducted to determine the optimal pH range, capacity to eliminate matrix and interference, extraction and elution times, and ideal quantity of resin beads. The Chelex-100 resins were determined to be inferior to the other resins in their ability to remove the matrix and interference. The properties of Nobias Chelate PA-1 and Presep® PolyChelate were comparable, whereas Presep® PolyChelate resins were ultimately chosen for sample analysis owing to their wide range for extracting Ga at low pHs compared to Nobias Chelate PA-1 resins. The optimal isotope dilution conditions for Ga concentration measurements in natural water are discussed. The procedural blank of the method was 0.42 ± 0.18 pmol/kg (N = 12, 1 SD) and the detection limit was 0.6 pmol/kg. Intercalibration samples of GS were analyzed, with results of 41.6 ± 1.06 pmol/kg (N = 6, 1 SD), which agreed with previously reported data. Other intercalibration samples (GSP, GSC, NASS-6, NASS-7, SAFe D1, and SAFe D2) were also measured. The Ga, sampled using the contamination-free X-Vane method and conventional CTD rosette samplers, were compared and showed no statistical difference. Ga concentrations in different natural waters were determined. The Ga concentrations in rainwater were extremely low, whereas those in river water and seawater were in good agreement with existing knowledge.

Anthracnose of Tribulus terrestris Caused by Colletotrichum truncatum in Northeast China.

Tribulus terrestris L. is an annual herbaceous medicinal plant of Zygophyllaceae, which is cultivated commercially in China. Subrotund or irregular gray, sunken, necrotic spots ranging from 2 to 9 mm were observed on diseased leaves of T. terrestris landrace in Fushun County, Liaoning Province of northeast China in July 2021, with more than 32% of the plants being infected in a 18-ha field. The symptoms first appeared on older leaves and gradually spread to younger leaves. The lesions developed a white center gradually and became perforated; multiple lesions could coalesce (Fig. 1). Ten symptomatic leaves were collected and the diseased tissues were cut into small pieces, immersed in 1% NaOCl for 2 min, rinsed three times with sterile water, and placed on acidified potato dextrose agar (PDA) in Petri dishes at 25°C in darkness. Fifteen suspected Colletotrichum single-spore fungal isolates (JL1 to JL15) with consistent morphological characteristics were obtained, and isolate JL6 was selected for identification and pathogenicity testing. Colonies on PDA were flat with an entire margin, dense and white at first, then became dark gray with numerous black microsclerotia and formed a concentric circular pattern with aging. Conidia were single-celled, sickle-curved with a tapered tip and truncate base, ranging from 16.46 to 20.26 µm in length and 2.81 to 3.96 µm in width (n=100). Setae were dark brown, septate, straight with a slightly acute tip, 75.45 to 135.63×3.19 to 4.95 µm in size. Appressoria were dark brown, round or irregular, mostly in groups. All characteristics were consistent with the descriptions of C. truncatum (Damm et al. 2009). Further confirmation of the identification was determined according to methods described previously (Damm et al. 2009). The rDNA internal transcribed spacer region (OP364400, 585 bp), and actin (OP380867, 290 bp), beta-tubulin (OP380868, 498 bp), chitin synthase 1 (OP380869, 277 bp), glyceraldehyde-3-phosphate dehydrogenase (OP380870, 280 bp), and histone (OP380871, 411 bp) genes were amplified by PCR and sequenced (Carbone and Kohn 1999; Glass and& Donaldson 1995; Guerber et al. 2003; O'Donnell and Cigelnik 1997). BLAST results showed 98-100% similarity at 85-97% coverage compared to the corresponding sequences of the type strain CBS 151.35 (GU227862, GU227960, GU228156, GU228352, GU228254, and GU228058). Phylogenetic analysis combining all loci revealed that the isolate JL6 and the type strains of C. truncatum clustered in one group (Fig. 2). One-year-old healthy seedlings of T. terrestris (cultivar: landrace) were used for pathogenicity test. Suspension (1×105 conidia/mL) of isolate JL6 was sprayed on ten seedlings, and ten seedlings sprayed with sterilized distilled water were used as the control. Three replicates were performed on each treatment. All plants were kept at 28±1°C (12 h photoperiod), and were evaluated after 7 days. The inoculated plants showed lesions on the leaf surface, similar to those in the field, and the control remained symptomless. The pathogen was successfully reisolated and identified using the methods mentioned above. To our knowledge, this is the first report of C. truncatum causing anthracnose on T. terrestris, which will provide valuable information for designing strategies to manage anthracnose on T. terrestris.

[Progress of studies on ATP-binding cassette transporters and transportation of secondary metabolites in medicinal plants].

ATP-binding cassette(ABC) transporters are one of the largest protein families in organisms, with important effects in regulating plant growth and development, root morphology, transportation of secondary metabolites and resistance of stress. Environmental stress promotes the biosynthesis and accumulation of secondary metabolites, which determines the quality of medicinal plants. Therefore, how to improve the accumulation of secondary metabolites has been a hotspot in studying medicinal plants. Many studies have showed that ABC transporters are extremely related to the transportation and accumulation of secondary metabolites in plants. Recently, with the great development of genomics and transcriptomic sequencing technology, the regulatory mechanisms of ABC transporters on secondary metabolites have attached great attentions in medicinal plants. This paper reviewed the mechanisms of different groups of ABC transporters in transporting secondary metabolites through cell membranes. This paper provided key theoretical basis and technical supports in studying the mechanisms of ABC transporters in medicinal plant, and promoting the accumulation of secondary metabolites, in order to improve the quality of medicinal plants.

[Analysis of head volatile constituents of Polyonum cuspidatum flower by HS-GC/MS].

OBJECTIVE: To analyze the floral volatiles of Polyonum cuspidatum flower. METHODS: The floral volatiles of P. cuspidaturn flower were investigated by Headspace Sampler GC/MS. RESULTS: 21 compounds were separated and determined from P. cuspidatumrn, which amounted to 99.29% of the total volatiles. 5 compounds including (E)-2-hyexenoic acid methyl ester, 1-phenyl-l-pentanone, (E)-4-hexenoic acid methyl ester, 3-hexenoic acid methyl ester, 2-methyl-6-methylene-1 and 7-octadien-3-one were the main constituents existed in P. cuspidatum flower, which amounted to 63.23% of the total volatiles. Organic ester compounds amounted to 52.09% of the total volatiles. Hexenoic acid methyl ester compounds were most, which amounted to 85.66% of the total organic ester compounds. In addition, the 1-phenyl-1-pentanone and acetophenone were 16.30% and 4.33%, which amounted to 20.63% of the total volatiles. CONCLUSION: The result of this research provides a scientific method for the reasonable exploitation and utilization of P. cuspidatum flower.

Randomized controlled study of plasma exchange combined with molecular adsorbent re-circulating system for the treatment of liver failure complicated with hepatic encephalopathy.

BACKGROUND/AIMS: To evaluate the use of plasma exchange (PE) combined with the molecular adsorbent re-circulating system (MARS) for the treatment of liver failure complicated with hepatic encephalopathy. METHODOLOGY: A prospective randomized controlled study was conducted to compare the therapeutic effect of MARS treatment (MARS group, n=60) with that of PE combined with MARS treatment (PE+MARS group, n=60) in patients with liver failure complicated with hepatic encephalopathy. RESULTS: The serum total bilirubin and blood ammonia levels were significantly decreased compared with pretreatment levels after 3 days of both the MARS treatment (p=0.0001, p<0.001) and PE+MARS treatment (both p<0.0001) and the Glasgow coma scale score was significantly increased (both p<0.0001). The 30-day mortality rate was 10.0% (6/60) in the MARS group and 11.7% (7/60) in the PE + MARS group. The per capita cost of treatment was significantly lower in the PE + MARS group than in the MARS group (p=0.0003). CONCLUSIONS: Both MARS and PE + MARS therapy can safely and effectively be used to treat liver failure complicated with hepatic encephalopathy, but PE + MARS therapy reduces serum total bilirubin level more effectively and is more cost-effective.

Anti-HBV effects of CpG oligodeoxynucleotide-activated peripheral blood mononuclear cells from patients with chronic hepatitis B.

Unmethylated CpG dinucleotides in bacterial DNA or synthetic oligodeoxynucleotides containing immunostimulatory CpG motifs (CpG ODN) are known as a potent Th1-like immune enhancer in vertebrates. Chronic hepatitis B is the immunocompromising condition. We therefore investigated the effects of CpG ODN on cultured cells from chronic hepatitis B patients and healthy controls. The inhibitory effects of CpG ODN on hepatitis B virus (HBV) were also studied. The secretion of IFN-alpha by CpG ODN-activated peripheral blood mononuclear cells (PBMCs) from chronic hepatitis B patients and healthy controls was significantly increased when compared with PBMCs alone or GpC ODN-stimulated PBMCs. After activation with CpG ODN, the IFN-alpha secretion by chronically HBV-infected patient PBMCs is less than that by healthy control PBMCs. Treatment of HepG2 2.2.15 cells with culture supernatants of PBMCs activated by CpG ODN can significantly suppress the secretion of HBsAg, HBeAg and HBV DNA as compared with that of PBMCs without CpG ODN activation under the same conditions. No inhibitory effect on the replication of HBV was found for CpG ODN treatment alone. Our results indicated that CpG ODN could efficiently enhance the immune response of chronic hepatitis B patients. Moreover, the CpG ODN-activated PBMCs from chronic hepatitis B patients were able to significantly inhibit HBV replication in vitro, suggesting that CpG ODN may be a potential immunoregulator against HBV infection in the future.