Divergent adaptation strategies of abundant and rare bacteria to salinity stress and metal stress in polluted Jinzhou Bay.

Understanding how abundant (AT) and rare (RT) taxa adapt to diverse environmental stresses is vital for assessing ecological processes, yet remains understudied. We collected sediment samples from Liaoning Province, China, representing rivers (upstream of wastewater outlet), estuaries (wastewater outlets), and Jinzhou Bay (downstream of wastewater outlets), to comprehensively evaluate AT and RT adaptation strategies to both natural stressors (salinity stress) and anthropogenic stressors (metal stress). Generally, RT displayed higher α- and ß-diversities and taxonomic groups compared to AT. Metal and salinity stresses induced distinct α-diversity responses in AT and RT, while ß-diversity remained consistent. Both subcommunities were dominated by Woeseia genus. Metal stress emerged as the primary driver of diversity and compositional discrepancies in AT and RT. Notably, AT responded more sensitively to salinity stress than RT. Stress increased topological parameters in the biotic network of AT subcommunities while decreasing values in RT subcommunities, concurrently loosening interactions of AT with other taxa and strengthening interactions of RT with others in biotic networks. RT generally exhibited greater diversity of metal resistance genes compared to AT. Greater numbers of genes related to salinity tolerance was observed for the RT than for AT. Compared to AT, RT demonstrated higher diversity of metal resistance genes and a greater abundance of genes associated with salinity tolerance. Additionally, deterministic processes governed AT community assembly, reinforced by salinity stress. However, the opposite trend was observed in the RT, where the importance of stochastic process gradually increased with metal stresses. The study is centered on exploring the adaptation strategies of both AT and RT to environmental stress. It underscores the importance of future research incorporating diverse ecosystems and a range of environmental stressors to draw broader and more reliable conclusions. This comprehensive approach is essential for gaining a thorough understanding of the adaptive mechanisms employed by these microorganisms.

AMIGO2 attenuates innate cisplatin sensitivity by suppression of GSDME-conferred pyroptosis in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of lung cancer. Cisplatin is commonly used in the treatment of many malignant tumours including NSCLC. The innate drug sensitivity greatly affects the clinical efficacy of cisplatin-based chemotherapy. As a plasma membrane adhesion molecule, amphoterin-induced gene and ORF-2 (AMIGO2) initially identified as a neurite outgrowth factor has been recently found to play a crucial role in cancer occurrence and progression. However, it is still unclear whether AMIGO2 is involved in innate cisplatin sensitivity. In the present study, we provided the in vitro and in vivo evidences indicating that the alteration of AMIGO2 expression triggered changes of innate cisplatin sensitivity as well as cisplatin-induced pyroptosis in NSCLC. Further results revealed that AMIGO2 might inhibit cisplatin-induced activation of (caspase-8 and caspase-9)/caspase-3 via stimulating PDK1/Akt (T308) signalling axis, resulting in suppression of GSDME cleavage and the subsequent cell pyroptosis, thereby decreasing the sensitivity of NSCLC cells to cisplatin treatment. The results provided a new insight that AMIGO2 regulated the innate cisplatin sensitivity of NSCLC through GSDME-mediated pyroptosis.

FGF9 inhibition by a novel binding peptide has efficacy in gastric and bladder cancer per se and reverses resistance to cisplatin.

Aberrant over-expressions of FGF9 in gastric cancer (GC) and its high-affinity receptor FGFR3c in bladder cancer (BC) provide possibilities for the treatment of GC and BC via targeting FGF9. In this study, we isolated a novel FGF9-binding peptide (P4) by screening a phage display random heptapeptide library. Sequence comparison showed that P4 shared high homology with the conserved motif in the immunoglobulin-like (Ig-like) domain II∼III (D2-D3) linker of the FGF9 high-affinity receptor (FGFR3c). The interaction between P4 and FGF9 was confirmed by the surface plasmon resonance (SPR) assay. Functional analysis indicated that P4 counteracted FGF9-induced aggressive phenotype, including cell proliferation, migration, and invasion in vitro, as well as suppressed tumor growth in vivovia down-regulation of the MAPKs and Akt cascades. More importantly, we found that FGF9 served as an underlying mechanism of the chemoresistance in GC and BC cells, and P4 could increase the sensitivity to the chemical agent via antagonizing the suppression effects of FGF9 on cell apoptosis. Taken together, our study identified a novel binding peptide for FGF9, which may serve as a potential therapeutic agent for malignant tumors featured by abnormally up-regulation of FGF9.

Identification of a crucial amino acid responsible for the loss of specifying FGFR1-KLB affinity of the iodinated FGF21.

Previous studies suggest that specific binding to the complex consisting of fibroblast growth factor receptor-1 (FGFR1) and the coreceptor beta-Klotho (KLB) is the premise for human FGF19 and FGF21 activating the downstream signaling cascades, and regulating the metabolic homeostasis. However, it was found that human FGF21 loses its ability to bind to FGFR1-KLB after iodination with Na125 I and chloramine T, whereas human FGF19 retained its affinity for FGFR1-KLB even after iodination. The molecular mechanisms underlying these differences remained elusive. In this study, we first demonstrated that an intramolecular disulfide bond was formed between cysteine-102 and cysteine-121 in FGF21, implying that the oxidation of the cysteine to cysteic acid, which may interfere with the active conformation of FGF21, did not occur during the iodination procedures, and thus ruled out the possibility of the two conserved cysteine residues mediating the loss of FGF21 binding affinity to FGFR1-KLB upon iodination. Site-directed mutagenesis and molecular modeling were further applied to determine the residue(s) responsible for the loss of FGFR1-KLB affinity. The results showed that mutation of a single tyrosine-207, but not the other five tyrosine residues in FGF21, to a phenylalanine retained the FGFR1-KLB affinity of FGF21 even after iodination, whereas replacing the corresponding phenylalanine residue with tyrosine in FGF19 did not alter its binding affinity to FGFR1-KLB, but decreased the receptor binding ability of the iodinated protein, suggesting that tyrosine-207 is the crucial amino acid responsible for the loss of specifying FGFR1-KLB affinity of the iodinated FGF21.

Antitumor effect of a short peptide on p53-null SKOV3 ovarian cancer cells.

Fibroblast growth factor-2 (FGF2) is a protein ligand, which exerts essential roles in development, angiogenesis, and tumor progression via activation of the downstream signaling cascades. Accumulating evidence has demonstrated that FGF2 is involved in the progression of ovarian cancer, providing a novel potential target for ovarian cancer therapy. In this study, we showed that FGF2 is significantly increased in ovarian tumors, and is negatively associated with the overall survival of ovarian cancer by database analysis. A short peptide obtained from a heptapeptide phage display library suppressed FGF2-induced proliferation, migration, and invasion of the p53-null epithelial ovarian cancer (EOC) cells. Further investigations revealed that the short peptide antagonized the effects of FGF2 on G0/G1 to S cell phase promotion, cyclin D1 expression, and MAPK and Akt signaling activation, which might contribute to the mechanism underlying the inhibitory effects of the short peptide on the aggressive phenotype of the ovarian cancer cells triggered by FGF2. Moreover, the short peptide might have the potentials of reversing FGF2-induced resistance to the doxorubicin via downregulation of the antiapoptotic proteins and counteracting of the antiapoptotic effects of FGF2 on p53-null EOC cells. Taken together, the short peptide targeting FGF2 may provide a novel strategy for improving the therapeutic efficiency in a subset of EOC.

Profiles and potential health risks of heavy metals in soil and crops from the watershed of Xi River in Northeast China.

Heavy metal soil contamination is a major environmental concern in China and has drawn significant public attention in recent years. The present study assessed the human health risk of four heavy metals (cadmium, lead, mercury, and zinc) through soil exposure and dietary intake in the watershed of Xi River, west of Shenyang, Liaoning Province, northeast China. Concentrations of Cd, Pb, Hg, and Zn were determined in 411 soil samples and 59 crop samples collected from this area. The health risks of heavy metal exposure via soil ingestion, inhalation, dermal contact, and dietary intake of crops were further estimated; total hazard index values were 1.15, 1.33, and 2.03 for the adult male, adult female, and children, respectively, and the total cancer risk was 3.7 × 10-3 for the local residents. Among the four investigated heavy metals, Cd was the primary pollutant posing health risks. The estimated non-carcinogenic and carcinogenic risks posed by the studied heavy metals were above the acceptable levels proposed by the U.S. EPA. Dietary intake of contaminated crops was identified as the predominant pathway for human heavy metal exposure in this area, suggesting that soil heavy metals can cause more harm when transported to the food chain. Overall, our findings suggest that the Xi River watershed is unsuitable for growing agricultural products, and more effective controls should be taken to curb future heavy metal pollution in the area.

Effects of acute and chronic exposures of fluoxetine on the Chinese fish, topmouth gudgeon Pseudorasbora parva.

Fluoxetine is a selective serotonin reuptake inhibitor used as an antidepressant and has been frequently detected in aquatic environments. However, its effects in fish from Asia remain relatively less studied. In this study, the topmouth gudgeon Pseudorasbora parva was exposed to 0, 50, and 200 µg/L of fluoxetine for 4 h and 42 d. The effects of fluoxetine on biometrics were compared to biochemical endpoints indicative of stress in different fish tissues (brain, liver, gills and intestine) following exposures. In fish exposed for 42 d, lipid peroxidation endpoints were enhanced 80% in the liver and gills. Acetylcholinesterase (AChE) activity was increased 40% after exposure to 50 µg/L and 55% at 200 µg/L following 4 h exposure. In contrast AChE was increased 26% (at 50 µg/L) after 42 d of exposures. Enhanced ethoxyresorufin-O-deethylase activity (EROD) was detected only in fish exposed to 50 µg/L of fluoxetine for 4 h. The activity of α-glucosidase (α-Glu) was also induced (at 200 µg/L) after 4 h of exposure. After 4 h of exposure, the activities of proteases in the intestine were generally inhibited at 200 µg/L. Both 4 h and 42 d exposures resulted in an increased hepatosomatic index (HSI) but did not affect the condition factor (CF). Our results demonstrate that fluoxetine significantly altered biochemical endpoints in P. parva after acute exposure and the morphological changes in liver size were not observed until 42 d of exposure.

Health risk assessment of heavy metals via dietary intake of wheat grown in Tianjin sewage irrigation area.

The possible health risks from heavy metal (Zn, Cu, Cr, Ni, Pb, and Cd) contamination to the local population through the food chain were evaluated in Tianjin, China, a city with a long history of sewage irrigation. Results showed that the continuous application of wastewater has led to an accumulation of heavy metals in the soil, and 54.5 and 18.25% soil samples accumulated Cd and Zn in concentrations exceeding the permissible limits in China. Concentrations of heavy metals in wheat grain decreased in the order of Zn > Cu > Cr > Ni > Pb > Cd, and transfer factors for the six heavy metals showed the trend as Zn > Cd > Cu > Pb > Cr > Ni. The risk assessment for the six heavy metals through wheat consumption suggests that concentrations of Cr and Cd in some wheat samples exceed their reference oral dose for adults and children. In general, no target hazard quotient value of any individual element was greater than one, which means they are within the safe interval. However, 36.4 and 63.6% hazard index values for adults and children were greater than one, respectively. The health risk due to the added effects of heavy metals was significant for children and adults, and more attention should be paid tothe potential added threat fromheavy metals to the health of children via dietary intake of wheat in Tianjin.

Metals and polycyclic aromatic hydrocarbons pollutants in industrial parks under valley landforms in Tibetan Plateau: Spatial pattern, ecological risk and interaction with soil microorganisms.

The spatial patterns of pollutants produced by industrial parks are affected by many factors, but the interactions among polycyclic aromatic hydrocarbons (PAHs), metals, and soil microorganisms in the valley landforms of the Tibetan Plateau are poorly understood. Thus, this study systematically investigated the distribution and pollution of metals and PAHs in soil around an industrial park in the typical valley landform of the Tibetan Plateau and analyzed and clarified the interaction among metals, PAHs, and microorganisms. The results were as follows: metal and PAH concentrations were affected by wind direction, especially WN-ES and S-N winds; Cd (2.86-54.64 mg·kg-1) had the highest soil concentrations of the metals screened, followed by variable concentrations of Cu, Pb, and Zn; the pollution levels of metals and PAHs in the S-N wind direction were lower than those in the WN-ES wind direction; the Cd content of Avena sativa in the agricultural soil around the factory exceeded its enrichment ability and food safety standards; the closer to the center of the park, the higher the ecological risk of PAHs; and the TEQ and MEQ values of the PAHs were consistent with their concentration distributions. The results of the soil microbial diversity and co-occurrence network in the dominant wind direction showed that metal and PAH pollution weakened the robustness of soil microbial communities. Additionally, the diversity and robustness of soil microbial communities at the S wind site were higher than those at the ES wind site, which might be attributed to the lower metal content of the former than the latter, which plays a negative role in the biodegradation of PAHs. The results of this study provide insights into the site selection, pollutant supervision, and environmental remediation of industrial parks in typical landforms.

Simultaneous stabilization of particulate and bioavailable arsenic in soils from the realgar mining area by polyacrylamide, nano-SiO2, and ferrihydrite composite materials.

Arsenic (As) contamination in realgar mining areas poses a severe environmental and health risk, highlighting the critical need for effective strategies to manage As migration, particularly in its particulate and bioavailable states. Soil erosion and water leaching serve as significant pathways for spreading As, emphasizing the imperative to curtail its mobility. In the present study, we proposed an effective strategy that combines the utilization of polyacrylamide (PAM), nano-SiO2 (NS), and ferrihydrite (Fh) to elevate the stability of As in soils from a realgar mining area. The results show that this composite material demonstrates the capability to concurrently regulate soil erosion and mitigate the leaching of bioavailable As. The combination of the three materials in the proportion of 0.5 % PAM +0.1 % NS + 1.0 % Fh can reduce the soil particulate and bioavailable As content by 99.11 % and 93.98 %, respectively. The unconfined compressive strength of the soil can be increased by about 30 % under this condition. The SEM analyses show that the addition of PAM and NS can significantly enhance the aggregation of soil particles and then reduce the soil erosion rate. These findings highlight the significant potential of the proposed approach in mitigating As contamination in soil within mining environments. The approach offers a sustainable and comprehensive solution to address the transport of heavy metal contaminants in both particulate and bioavailable states in mining areas.

Iodide and sulfite synergistically accelerate the photo-reduction and recovery of As(V) and As(III) in sulfite/iodide/UV process: Efficiency and mechanism.

Photo-reduction of arsenic (As) by hydrated electron (eaq-) and recovery of elemental arsenic (As(0)) is a promising pathway to treat As-bearing wastewater. However, previously reported sulfite/UV system needs large amounts of sulfite as the source of eaq-. This work suggests a sulfite/iodide/UV approach that is more efficient and consumes much less chemical reagents to remove As(III) and As(V) and recover valuable As(0) from wastewater, hence preventing the production of large amounts of As-containing hazardous wastes. Our results showed that more than 99.9% of As in the aqueous phase was reduced to highly pure solid As(0) (>99.5 wt%) by sulfite/iodide/UV process under alkaline conditions. Sulfite and iodide worked synergistically to enhance reductive removal of As. Compared with sulfite/UV, the addition of iodide had a substantially greater effect on As(III) (over 200 times) and As(V) (approximately 30 times) removals because of its higher absorptivity and quantum yield of eaq-. Furthermore, more than 90% of the sulfite consumption was decreased by adding a small amount of iodide while maintaining similar reduction efficiency. Hydrated electron (eaq-) was mainly responsible for As(III) and As(V) reductions and removals under alkaline conditions, while both SO3•- and reactive iodine species (e.g., I•, I2, I2•-, and I3-) may oxidize As(0) to As(III) or As(V). Acidic circumstances caused sulfite protonation and the scavenging of eaq- by competing processes. Dissolved oxygen (O2) and CO32- prevented As reduction by light blocking or eaq- scavenging actions, but Cl-, Ca2+, and Mg2+ showed negligible impacts. This study presented an efficient method for removing and recovering As from wastewater.

Molecular composition and characteristics of Sediment-adsorbed Dissolved Organic Matter (SDOM) along the coast of China.

Sediment-adsorbed Dissolved Organic Matter (SDOM) in coast plays a crucial role in the terrestrial and marine carbon cycle processes of the global environment. However, understanding the transport dynamics of SDOM along the coast of China, particularly its interactions with sediments, remains elusive. In this study, we analyzed the δ13C and δ15N stable isotopic compositions, as well as the molecular characteristics of SDOM collected from coastal areas spanning the Bohai Sea (BS), Yellow Sea (YS), East China Sea (ECS), and South China Sea (SCS), by using isotope ratio mass spectrometry and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS). We identified the predominant sources of carbon and nitrogen in coastal sediments, revealing terrigenous origins for most C and N, while anthropogenic sources dominated in the SCS. Spatial variations in SDOM chemodiversity were observed, with diverse molecular components influenced by distinct environmental factors and sediment sources. Notably, lignins and saturated compounds (such as proteins/amino sugars) were the predominant molecular compounds detected in coastal SDOM. Through Mantel tests and Spearman's correlation analysis, we elucidated the significant influence of spatial environmental factors (temperature, DO, salinity, and depth) and sediment sources on SDOM molecular chemodiversity. These findings contribute to a more comprehensive understanding of the carbon cycle dynamics along the Chinese coast.

Effects of denitrification on speciation and redistribution of arsenic in estuarine sediments.

Microbially-mediated redox processes involving arsenic (As) and its host minerals significantly contribute to the mobilization of As in estuarine sediments. Despite its significance, the coupling between As dynamics and denitrification processes in these sediments is not well understood. This study employed sequential sediment extractions and simultaneous monitoring of dissolved iron (Fe), nitrogen (N), and sulfur (S) to investigate the impact of nitrate (NO3-) on the speciation and redistribution of As, alongside changes in microbial community composition. Our results indicated that NO3- additions significantly enhance anaerobic arsenite (As(III)) oxidation, facilitating its immobilization by increased adsorption onto sediment matrices in As-contaminated estuarine settings. Furthermore, NO3- promoted the conversion of As bound to troilite (FeS) and pyrite (FeS2) into forms associated with Fe oxides, challenging the previously assumed stability of FeS/FeS2-bound As in such environments. Continuous NO3- additions ensured As and Fe oxidation, thereby preventing their reductive dissolution and stabilizing the process that reduces As mobility. Changes in the abundance of bacterial communities and correlation analyses revealed that uncultured Anaerolineaceae and Thioalkalispira may be the main genus involved in these transformations. This study underscores the critical role of NO3- availability in modulating the biogeochemical cycle of As in estuarine sediments, offering profound insights for enhancing As immobilization techniques and informing environmental management and remediation strategies in As-contaminated coastal regions.

Bacterial community in the metal(loid)-contaminated marine vertical sediments of Jinzhou Bay: Impacts and adaptations.

Metal(loid) discharge has led to severe coastal contamination; however, there remains a significant knowledge gap regarding its impact on sediment profiles and depth-resolved bacterial communities. In this study, geochemical measurements (pH, nutrient elements, total and bioavailable metal(loid) content) consistently revealed decreasing nitrogen, phosphorus, and metal(loid) levels with sediment depth, accompanied by reduced alpha diversity. Principal coordinate analysis indicated distinct community compositions with varying sediment depths, suggesting a geochemical influence on diversity. Ecological niche width expanded with depth, favoring specialists over generalists, but both groups decreased in abundance. Taxonomic shifts emerged, particularly in phyla and families, correlated with sediment depth. Microbe-microbe interactions displayed intricate dynamics, with keystone taxa varying by sediment layer. Zinc and arsenic emerged as key factors impacting community diversity and composition using random forest, network analysis, and Mantel tests. Functional predictions revealed shifts in potential phenotypes related to mobile elements, biofilm formation, pathogenicity, N/P/S cycles, and metal(loid) resistance along sediment profiles. Neutral and null models demonstrated a transition from deterministic to stochastic processes with sediment layers. This study provides insights into the interplay between sediment geochemistry and bacterial communities across sediment depths, illuminating the factors shaping these ecosystems.

Aerobic Se(IV) reducing bacteria and their reducing characteristics in estuarine sediment.

Microorganisms play a critical role in the biogeochemical cycling of selenium in natural ecosystems, particularly in reducing selenite (Se(IV)) to element selenium (Se(0)) which reduces its mobility and bioavailability. However, Se(IV)-reducing bacteria and their reducing characteristics in estuarine sediments remain inadequately understood. In this study, the reduction of Se(IV) was confirmed to be microbially driven through the cultivation of a mixture of estuarine sediment and Se(IV) under aerobic conditions. Community analysis indicates that Bacillus was primarily involved in the reduction of Se(IV). A strain with high salt tolerance (7.5 % NaCl) and Se(IV) resistance (up to 200 mM), Bacillus cereus SD1, was isolated from an estuarine sediment. The reduction of Se(IV) occurred concomitantly with the onset of microbial growth, and reduction capacity increased approximately 5-fold by adjusting the pH. In addition, Se(IV) reduction in Bacillus cereus SD1 was significantly inhibited by sulfite, and the key enzyme activity tests revealed the possible presence of a sulfite reductase-mediated Se(IV) reduction pathway. These research findings provide new insights into the bioreducing characteristics and the biogeochemical cycling of selenium in estuarine environments.

Synergistic anti-tumour activity of ginsenoside Rg3 and doxorubicin on proliferation, metastasis and angiogenesis in osteosarcoma by modulating mTOR/HIF-1α/VEGF and EMT signalling pathways.

OBJECTIVES: The most common cause of osteosarcoma (OS) death is lung metastasis. Currently, doxorubicin is the primary chemotherapy drug used to treat OS, however, it is not effective in inhibiting metastasis, and it has obvious cardiotoxicity. The anticancer activity of ginsenoside Rg3 has been demonstrated in a variety of malignant tumours. The aim of this study was to determine the potential role of ginsenoside Rg3 and doxorubicin in OS and the possible mechanism. METHODS: The potential synergistic effects of ginsenoside Rg3 and doxorubicin on human osteosarcoma cells 143B and U2OS, human umbilical vein endothelial cells, and mice receiving 143B xenografts and lung metastases were investigated. KEY FINDINGS: Our study demonstrated that the combination of ginsenoside Rg3 and doxorubicin significantly inhibited cell proliferation, metastasis and angiogenesis in vitro. Mechanically, the anti-tumour activity of ginsenoside Rg3 and doxorubicin by modulating mTOR/HIF-1α/VEGF and EMT signalling pathways. Furthermore, ginsenoside Rg3 combined with doxorubicin inhibits tumour growth and lung metastasis in 143B-derived murine osteosarcoma models. More importantly, ginsenoside Rg3 can effectively ameliorate doxorubicin-induced weight loss and cardiotoxicity in mice. CONCLUSIONS: Consequently, we concluded that the combination of ginsenoside Rg3 and doxorubicin displayed an evidently synergistic effect, which has the potential to be used as an effective and safe therapeutic approach for OS treatment.

Diversity, functional potential, and assembly of bacterial communities in metal(loid)-contaminated sediments from a coastal industrial basin.

A comprehensive understanding of ecological processes related to bacterial communities in these ecosystems is critical for improving the sustainability of estuarine-coastal ecosystem functions. However, the community composition, functional potential, and assembly mechanisms of bacterial community in metal(loid)-contaminated estuarine-coastal habitats remain poorly understood, especially along lotic systems extending from rivers to estuaries and to bays. Here, we collected sediment samples associated with sewage outlets from rivers (upstream/midstream of sewage outlet), estuaries (sewage outlets), and Jinzhou Bay (downstream of sewage outlets) within Liaoning Province, China in order to evaluate the relationships between microbiome and metal(loid) contamination. Sewage discharge markedly increased the concentrations of metal(loid)s in sediments, including of As, Fe, Co, Pb, Cd, and Zn. Significant discrepancies in alpha diversity and community composition were observed among the sampling sites. The above dynamics were primarily caused by salinity and metal(loid) concentrations (i.e., of As, Zn, Cd, and Pb). Furthermore, metal(loid) stress significantly increased abundances of metal(loid)-resistant genes, but decreased abundances of denitrification genes. Dechloromonas, Hydrogenophaga, Thiobacillus, and Leptothrix were denitrifying bacteria present within sediments of this estuarine-coastal ecosystem. Moreover, the stochastic processes dominated the community assembly in estuary offshore sites, while deterministic processes dominated river community assembly mechanisms. Salinity and total nitrogen concentration, rather than metal(loid) concentrations, governed the assembly processes in these sites. Overall, these elucidate mechanisms involved in constructing community diversities, functional potential, and assembly.

Enhancement of arsenic uptake and accumulation in green microalga Chlamydomonas reinhardtii through heterologous expression of the phosphate transporter DsPht1.

Arsenate (AsV) is a predominant arsenic contaminant in aerobic water. Microalgae have been recently used in the phytoremediation of arsenic-contaminated water. However, the amount of AsV uptake in microalgae is limited, which hinders the application of microalgae in arsenic-contaminated water treatment. Here, we found that the expression of a novel phosphate transporter DsPht1 in Dunaliella salina was highly upregulated after AsV exposure. Fluorescent protein-tagging analysis showed the plasma membrane location of DsPht1. Furthermore, DsPht1 was overexpressed in a model microalga Chlamydomonas reinhardtii. The DsPht1 transgenetic lines accumulated up to 6.4-fold higher total arsenic than the untransformed line, and the AsV amount in total arsenic increased by 8.3-fold. Moreover, the organoarsenic content was also higher in the transgenetic lines. Overall, the DsPht1 transformants generated in this study increased arsenate uptake and transformation, which are promising for the effective phytoremediation of arsenic-contaminated water.

Direct immobilization of Se(IV) from acidic Se(IV)-rich wastewater via ferric selenite Co-precipitation.

The attenuation of acidic Se(IV)-rich wastewater, including those associated with acid mine drainage (AMD) and nonferrous metallurgical wastewater (NMW), presents a serious environmental challenge. This study investigates the effects of diverse factors from pH values to Se(IV)/Fe(III) molar ratios, initial Se(IV) concentrations, and alkali neutralization agents on the direct co-precipitation of ferric selenites in AMD and NMW systems involving different orders of Fe(III) and alkali addition. Our results show that amorphous sulfate-substituted ferric (hydrogen) selenite and Se(IV)-bearing ferrihydrite-schwertmannite are the major Se(IV)-attenuation solids except that gypsum is an additional phase in the NMW system with Ca(OH)2 neutralization. Produced ferric selenites achieve 98-99.8% of Se(IV) immobilization under optimal conditions of pH 4.5, Se(IV)/Fe(III) molar ratios of 0.0625-0.5, and initial Se(IV) concentrations of 0.15-1.3 mmol·L-1. Moreover, completing FeSO4+ and FeHSeO32+/FeSeO3+ complexes as well as different ferric selenite co-precipitates are shown to collectively control aqueous Se(IV) remaining. Specifically, three distinct trends of aqueous Se(IV) concentrations separately correspond to changes in the four factors. The co-precipitation in the NMW system via pH adjustment followed by Fe(III) addition is more efficient for Se(IV) fixation than that in the AMD system because of minimal complexation, concurrent Fe(III) hydrolysis, and enhanced ferric selenite co-precipitation in the former.

FTY720 mediates activation suppression and G(0)/G (1) cell cycle arrest in a concanavalin A-induced mouse lymphocyte pan-activation model.

OBJECTIVE: FTY720 is a potent drug for multiple sclerosis treatment. To biologically address its possible applications to more generalized diseases with aberrant inflammation, we are testing whether FTY720 can function as a lymphocyte cell cycle blocker and activation suppressor via a concanavalin A (ConA)-mediated mouse lymphocyte pan-activation model. METHODS: Mouse lymphocytes were obtained from lymph nodes and subjected to ConA and/or FTY720 treatment. Cell viability was assayed by MTT and mitochondrial assays. Early and late activation, cell cycle, proliferation and intracellular Ca(2+) concentration ([Ca(2+)](i)) were analyzed by flow cytometry. RESULTS: At concentrations of less than 500 nM, FTY720 significantly down-regulated both CD69 and CD25 expressions of T cells, as well as inhibiting proliferation of activated lymphocytes. In addition, FTY720 blocked the ConA-induced mitogenesis, exhibiting lymphocyte G(0)/G(1) phase cell cycle arrest with significant reduction of cells in S and G(2)/M phases. Meanwhile, a significant decline in [Ca(2+)](i) was observed. The correlation of [Ca(2+)](i) and cell cycle arrest were validated by employing a [Ca(2+)](i) inhibitor SK&F 96365 and testing with and without FTY720 treatment. CONCLUSION: We demonstrated that FTY720 induces G(0)/G(1) phase cell cycle arrest, resulting in proliferation inhibition upon lymphocyte pan-activation, which may be related to reduction of overall intracellular Ca(2+) load.