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Chemokines are important regulators of the immune system, inducing specific cellular responses by binding to receptors on immune cells. In SLE patients, decreased expression of CCL2 on mesenchymal stem cells (MSC) prevents inhibition of B-cell proliferation, causing the characteristic autoimmune phenotype. Nevertheless, the intrinsic role of CCL2 on B-cell autoimmunity is unknown. In this study using Ccl2KO mice, we found that CCL2 deficiency enhanced BCR signaling by upregulating the phosphorylation of the MST1-mTORC1-STAT1 axis, which led to reduced marginal zone (MZ) B cells and increased germinal center (GC) B cells. The abnormal differentiation of MZ and GC B cells were rescued by in vivo inhibition of mTORC1. Additionally, the inhibition of MST1-mTORC1-STAT1 with specific inhibitors in vitro also rescued the BCR signaling upon antigenic stimulation. The deficiency of CCL2 also enhanced the early activation of B cells including B-cell spreading, clustering and signalosome recruitment by upregulating the DOCK8-WASP-actin axis. Our study has revealed the intrinsic role and underlying molecular mechanism of CCL2 in BCR signaling, B-cell differentiation, and humoral response.

ABSTRACTMicrocystis aeruginosahas several morphological and physiological traits that frequently enable it to dominate in eutrophic waters. Sanguinarine is a promising algaecide of biological origin that shows strong inhibitory effects against M. aeruginosa. The effects of sanguinarine on the morphological and physiological characteristics that give M. aeruginosaan ecologically competitive advantage over other phytoplankton were investigated in this study. The results showed that sanguinarine could effectively inhibit the growth of M. aeruginosa. Sanguinarine did not affect buoyancy regulation in M. aeruginosabut did increase colony size. Examination of intracellular and extracellular microcystin showed that although its synthesis was inhibited by sanguinarine, it recovered after 5 days of exposure at concentrations of 10 to 40 μg l−1. Hormetic effects were observed for phycobiliprotein content and carbonic anhydrase (CA) activity under sanguinarine stress. Phosphorus (P) uptake by M. aeruginosawas inhibited by sanguinarine. The results presented in this study will help elucidate the ecological effects of sanguinarine when used to mitigate the effects of harmful cyanobacteria.

•C. flumineapromoted the sedimentation of AgNPs.•PVP-coated AgNPs induced oxidative stress in C. fluminea.•C. flumineacould be a good indicator for AgNPs freshwater pollution.•AgNPs had long gut retention time in C. fluminea.

Although humic acid (HA) plays an important role in the fate and transport of nanoparticles in subsurface environments, the roles of specific fractions of HA in the transport of nanoparticles are still not well understood. In this study, quantum dots (QDs) with carboxyl and amino modifications (QD–COOH and QD–NH2) were used as typical nanoparticles to understand the effects of molecular weight (MW) fractionated humic acid (Mf-HA) on the transport and retention behaviour of nanoparticles. Transport experiments on QDs were performed both in the absence and presence of pristine- and Mf-HA in both NaCl and CaCl2solutions at pH 7.0. The Mf-HA had distinct effects on the transport and retention behavior of QDs, which were highly dependent on the MW of the Mf-HA. In addition, the surface coating of the QDs and cation types also showed significant effects on the transport behavior of QDs. In NaCl solution, the transport of QD–NH2was dramatically enhanced in the presence of pristine- and Mf-HA, and the high MW Mf-HA (>100 kDa and 30–100 kDa) could enhance the mobility of the QDs more significantly than the low MW Mf-HA (10–30 kDa, 3–10 kDa, and <3 kDa). QD–COOH was readily mobile in the sand column and the recovery of injected QD–COOH was significantly higher in the presence of pristine- and Mf-HA. In CaCl2solution, the transport of QD–COOH was enhanced in the presence of pristine- and Mf-HA, and the enhancement significantly correlated with the MW of the Mf-HA. However, the transport behavior of QD–NH2was not altered by the pristine- and Mf-HA. Overall, these findings can improve our understanding of the effects of Mf-HA on the transport and retention of nanoparticles in subsurface environments, and suggest that the HA, surface coating and cation types are likely key factors which govern the stability and mobility of nanoparticles in the natural environment.

Abstract:Biologically derived algicidal substances are regarded as environmentally friendly in the control of harmful cyanobacterial blooms. To evaluate the possible control of Microcystis-based water blooms using fruit from Macleaya cordata(MC-fruit), the effects of MC-fruit on the growth, polyphasic chlorophyll fluorescence transients, microcystin production and efficacy of in situcyanobacterial bloom removal were investigated. The results showed that MC-fruit could effectively inhibit the growth of M. aeruginosaPCC7806 at a concentration of 1 mg l−1. MC-fruit stress caused severe damage to photosynthesis of M. aeruginosaand decreased the content of cellular microcystin-LR. The results of an in situfield test showed that MC-fruit effectively reduced the biomass of Microcystisand improved water quality. Accordingly, MC-fruit may be a useful biologically derived algicide for cyanobacterial bloom control.

The growing potential of quantum dots (QDs) in biological and biomedical applications has raised considerable concern due to their toxicological impact. Consequently, it is urgent to elucidate the underlying toxicity mechanism of QDs. In this work, we comprehensively investigated the cellular uptake of four CdSe/ZnS QDs (COOH CdSe/ZnS 525, COOH CdSe/ZnS 625, NH2CdSe/ZnS 525, and NH2CdSe/ZnS 625) and induced physiological responses in Phanerochaete chrysosporium(P. chrysosporium) through inductively coupled plasma optical emission spectroscopy, confocal laser scanning microscopy, and the determination of malondialdehyde content, superoxide level, superoxide dismutase activity, catalase activity and glutathione level. The results showed that the four CdSe/ZnS QDs accumulated largely in the hyphae and caused oxidative stress to P. chrysosporiumin the tested concentration range (10–80 nM). Furthermore, the cellular uptake and cytotoxicity were related to the physicochemical properties of the QDs, such as particle size and surface charges. Negatively charged CdSe/ZnS QDs with small size could be more easily ingested by P. chrysosporiumthan large ones; thus small size CdSe/ZnS QDs were more cytotoxic to P. chrysosporium. On the other hand, small negatively charged CdSe/ZnS QDs resulted in greater cytotoxicity than large negatively charged CdSe/ZnS QDs. The obtained results offer valuable information for revealing the toxicity mechanism of QDs in living cells.

Water pollution caused by heavy metals poses a serious threat to the ecological environment and human health, which requires the exploration of efficient, economical and convenient methods to solve such urgent problems. In this work, agricultural waste straw was prepared and modified by spinel bimetal through sol-gel method to obtain novel MnFe2O4loaded biochar with the purpose of efficiently cadmium (Cd) removal from water. Results showed that the as-prepared composites showed much higher Cd adsorption capacity as compared to the original biochar (127.37 vs 25.73 mg/g). Further investigation showed that the integrity of crystal plane structure contributes to the appearance of net-like pore and the 18-fold enlarged specific surface area. Strong anti-interference ability of the spinel loaded biochar was observed in binary and quaternary systems through adsorption affinity investigation using separation factor (αMetalCd, Metal=Pb, Zn, Cu). Due to its magnetic properties, the adsorbent was easily separated and recovered from aquatic solutions, and the adsorption capacity showed little decrease after five cycles. This work provided the references for resource utilization of agricultural wastes and its application in wastewater treatment.

The toxicity of silver nanoparticles (AgNPs) is widely exploited, but their hormesis effect has, so far, received little attention. This study reports the hormesis effect at low AgNPs concentrations of 0.34 mg L−1, with a 29.9% increase in bacterial viability compared with the control. Cysteine can induce a hormesis effect at a higher concentration. 12.5 mg L−1cysteine induced a hormesis effect in the AgNP concentration range of 1.7–5.1 mg L−1. Results suggest that this cysteine-induced hormesis effect is concentration-dependent; the concentration that make sulfuration rate (ns/nAg) of 6.15 shows strong excitation to cells.

The extensively used neonicotinoid pesticides are reported seriously threatened ecological environment and even human health, which is one of the most urgent environmental problems. In this study, the bioremediation of thiamethoxam contaminated wetland soil by Phanerochaete chrysosporiumand the analysis of microorganisms' response was conducted. Results showed that P. chrysosporiumimproved thiamethoxam degradation both in non-sterilized and sterilized soils. Obvious bioaugmentation of thiamethoxam degradation was especially found in non-sterilized soil at the earlier stage (< 10 d). The pH of the soils increased accompanied with the decreasing in organic matter after remediation. Increase in invertase activity and decrease in urease activity was observed, while the catalase activity changed little. Microbial community analysis illustrated that phyla Proteobacteria, Actinobacteria, Firmicutes, and Bacteroideteswere the dominate species for bacteria, and phyla Ascomycota, Basidiomycotawere the dominate species for fungi. P. chrysosporiuminoculation in different modes shifted the composition and relative abundance of microbial community differently, but increased in microbial diversity in soil was observed overall. The obtained results proved that white-rot fungus P. chrysosporiumenhanced elimination was available for bioremediation of thiamethoxam contaminated soil.

This study investigated the effects of biochars pyrolyzed at different temperatures on plant germination and growth and attempted to determine the mechanisms underlying those effects. The experimental results showed that phytotoxicity of biochar pyrolyzed at 500 or 800 °C was significantly higher than that of biochar pyrolyzed at 200 °C, especially at high dosages (200.0 and 300.0g/L). However, concentrations of heavy metals and polycyclic aromatic hydrocarbon (PAHs) in biochar pyrolyzed at 500 and 800 °C were lower than those in biochar pyrolyzed at 200 °C. The inhibitory effect of aqueous biochar extract on seed germination was significantly weaker than that of biochar. Electron paramagnetic resonance (EPR) signal intensity was enhanced with increasing pyrolysis temperature, which indicates the existence of a greater number of free radicals. Furthermore, •OH and •O2−were the primary reactive oxygen species in the biochar system. It can be concluded that the phytotoxicity of biochar pyrolyzed at high temperatures (>500 °C) enables to attributing free radical-induced oxidative damage, whereas that of biochar produced at low temperatures (200 °C) results in the presence of conventional contaminants (such as heavy metals and PAHs). The information obtained in this study provides a more comprehensive understanding of the potential risk of free radicals in plant system biochar.