Microcystis aeruginosa aggravated arsenic accumulation in silver carp during silver carp controlling algal bloom in arsenic-contaminated water.

Silver carp mediated biological control techniques are often advocated for controlling cyanobacteria blooms in eutrophic water, which are often enriched with arsenic (As). However, the transfer and fate of As during the biological control of cyanobacteria blooms by silver carp in As-rich eutrophic water remain unclear. Based on the simulated ecosystem experiment, the accumulation of As in silver carp and the transfer and fate of As in the water-algae-silver carp system during Microcystis aeruginosa blooms controlled by silver carp were investigated. Microcystis aeruginosa showed high tolerance to As(V). The accumulation of As in different tissues of silver carp was different, as follows: intestine > liver > gill > skin > muscle. After silver carp ingested As-rich Microcystis aeruginosa, As accumulation in the intestine, liver, gill, and skin of silver carp was enhanced under the action of digestion and skin contact. Compared with the system without algal, As accumulation in the intestine, liver, gill, and skin of silver carp increased by 1.1, 3.3, 3.3, and 9.6 times, respectively, after incubation for 30 days in the system with Microcystis aeruginosa, while the accumulation of As in the muscle was only slightly increased by 0.56 mg/kg. This work revealed the transfer and fate of As during algal control by silver carp, elucidated the accumulation mechanism of As in water-algae-silver carp system, enriched our understanding of As bioaccumulation and transformation in As-rich eutrophication water, and provided a scientific basis for assessing and predicting As migration and enrichment in water-algae-silver carp system.

Manganese promotes stability of natural arsenic sinks in a groundwater system with arsenic-immobilization minerals: Natural remediation mechanism and environmental implications.

Arsenic (As)-immobilizing iron (Fe)-manganese (Mn) minerals (AFMM) represent potential As sinks in As-enriched groundwater environments. The process and mechanisms governing As bio-leaching from AFMM through interaction with reducing bacteria, however, remain poorly delineated. This study examined the transformation and release of As from AFMM with varying Mn/Fe molar ratios (0:1, 1:5, 1:3, and 1:1) in the presence of As(V)-reducing bacteria specifically Shewanella putrefaciens CN32. Notably, strain CN32 significantly facilitated the bio-reduction of As(V), Fe(III), and Mn(IV) in AFMM. In systems with Mn/Fe molar ratios of 1:5, 1:3, and 1:1, As bio-reduction decreased by 28%, 34%, and 47%, respectively, compared to the system with a 0:1 ratio. This Mn-induced inhibition of Fe/As bio-reduction was linked to several concurrent factors: preferential Mn bio-reduction, reoxidation of resultant Fe(II)/As(III) due to Mn components, and As adsorption onto emergent Fe precipitates. Both the reductive dissolution of AFMM and the bio-reduction of As(V) predominantly controlled As bio-release. Structural equation models indicated that reducing bacteria destabilize natural As sinks more through As reduction than through Mn(II) release, Fe reduction, or Fe(II) release. Systems with Mn/Fe molar ratios of 1:5, 1:3, and 1:1 showed a decrease in As bio-release by 24%, 41%, and 59%, respectively, relative to the 0:1 system. The observed suppression of As bioleaching was ascribed to both the inhibition of As/Fe bio-reduction by Mn components and the immobilization of As by freshly generated Fe precipitates. These insights into the constraining effect of Mn on the biotransformation and bioleaching of As from AFMM are crucial for grasping the long-term stability of natural As sinks in groundwater, and enhance strategies for in-situ As stabilization in As-afflicted aquifers through Nature-Based Solutions.

Efficient removal of microplastics from aqueous solution by a novel magnetic biochar: performance, mechanism, and reusability.

Microplastics' (MPs) pollution removal from water bodies has become an urgent task to ensure water quality safety and water ecological security on a global scale. In this work, coprecipitation was employed to investigate the adsorption of MPs by magnetic biochar (MRB) prepared from agricultural waste rice husks in an aquatic system. The results showed that MRB can adsorb up to 99.96% of MPs in water; acidic conditions were favorable for the effective MPs' adsorption reaction, and competing anions had a greater effect on adsorption. The adsorption mechanism results revealed that the adsorption of MPs by MRB was a spontaneous process, and electrostatic attraction, surface complexation, hydrogen bonding and π-π interactions were present in the adsorption process. Furthermore, after the adsorption of MPs, MRB can be recovered by thermal treatment (500 °C) and still exhibits up to 90% MPs adsorption (after four uses). This work reveals that MRB is an inexpensive, efficient, and reusable nanoscale adsorbent for MPs pollution removal in water, which may provide new ideas for microplastic pollution control in the aqueous environment.

Synthesis, characterization and antimicrobial property in vitro of supramolecular coordination polymers bearing brominated Schiff base ligand.

In this study, two supramolecular coordination polymers of Co(II) and Zn(II) based on brominated Schiff base (E)-4-bromo-2-((quinolin-6-ylimino)methyl)phenol (HL) were synthesized and characterized by using elemental analysis, IR spectroscopy and NMR spectroscopy. Furthermore, the crystal structures of HL, CoL2 (І) and ZnL2 (II) were determined by single crystal X-ray analysis. It was revealed that the bromine-related interaction played important role in the self-assembly of HL supramolecular network. The crystal structural investigations revealed that І and II were isomorphous with the same geometry around the metal atom and similar structural feature. The stable four-membered chelate structure resulted from coordination between the metal(II) ion and deprotonated bidentate ligand. And supramolecular coordination polymers of І and II formed diverse architecture through multiple hydrogen bondings, π···π interactions and halogen-related interactions. Antimicrobial activities of polymers were tested toward four bacteria and five phytopathogenic fungi. І and II showed higher activities toward the tested microorganisms than HL. Furthermore, the photoluminescence results indicated that HL and II accompanied with better fluorescence properties in the ultraviolet region.

Effect of biochar on immobilization remediation of Cd⁃contaminated soil and environmental quality.

PURPOSE: Field experiments were conducted to explore the remediation effects of ordinary biochar and PEI-modified biochar on the Cd-contaminated yellow brown soil, and the improvement of soil environment quality in southern Shaanxi province, so as to provide theoretical basis and technical support for in-situ remediation of Cd-contaminated soil in southern Shaanxi province. RESULTS AND DISCUSSION: Biochar applied in soil could increase the soil pH value, EC, ECEC, and SOC, and improve the soil physical and chemical properties to a certain extent. Biochar in soil could change the chemical form of Cd in soil, effectively passivate Cd in soil and reduce its bio-availability. Biochar could enhance the activities of catalase, urease, alkaline phosphatase and sucrase in soil to different degrees, and the four soil enzymes could be used as indicators of passivation effects of soil Cd by biochar. With biochar treatment, soil aggregates MWD and GMD increased to different degrees, so biochar could enhance soil stability. The biochar could decrease the content of Cd in different parts of wheat, the content of Cd in wheat grains had a highly significant positive correlation with the available content of Cd in soil, and highly significant or significant negative correlations with pH, SOC, EC, ECEC, and the activities of phosphatase, urease and sucrase in soil. Compared with ordinary biochar, the passivation effect of PEI-modified biochar on Cd was more significant. CONLUSIONS: The results of the study indicated that ordinary biochar and PEI-modified biochar could passivate the Cd in soil, and remediate Cd-contaminated soil, and improve the soil environmental quality effectively, compared with ordinary biochar, the PEI-modified biochar produced batter.

Effects of heavy metals on microorganisms and enzymes in soils of lead-zinc tailing ponds.

Taking the soil around the lead-zinc tailings pound in the upper reaches of the Hanjiang River in Shaanxi Province as the research object, with tailings pond as the center, seven different belt zones were divided outwards, the contents of Pb, Cu, Zn, V, Ni, Cd in soil were analyzed, as well as soil basic respiration (SBR), microbial biomass carbon (MBC), microbial metabolic quotient (MMQ), and the activities of catalase, urease, cellulase, invertase and neutral phosphatase were also determined. The purpose was to reveal the intrinsic relationship between soil microbial, enzyme activities and heavy metal pollution, and to establish the characterization system of enzyme activities, soil heavy metal pollution degree, as well as microbial parameters. The results showed that: (1) The potential ecological risk index of six heavy metals was ranked as Cd > Cu > Pb > Ni > Zn > V. Cd was a high potential ecological risk, Cu was a medium potential ecological risk, and Zn, Pb, V and Ni were low potential ecological risk. The comprehensive evaluation result of Hakanson's potential ecological hazard index showed that, Zone I was of high potential risk level, Zone II, III and IV were of medium risk level, and Zone V, VI and VII were of low level. (2) Microbial biomass carbon (MBC) had a significant negative correlation or extremely significant negative correlation with 6 heavy metals, and microbial metabolic quotient (MMQ) had a significant positive correlation or extremely significant positive correlation with 6 heavy metals. MBC and MMQ were effective microbiological indexes to measure the quality status of soil, while SBR was not. (3) Catalase, cellulase, sucrase and neutral phosphatase activity had significant negative correlation with the contents of 6 heavy metals, and they could replicate the pollution degree of substantial metals in the soil. However, urease had no significant correlation with the contents of 6 heavy metals, which could not reflect the pollution degree of soil heavy metals.

Removal of Cadmium from Contaminated Groundwater Using a Novel Silicon/Aluminum Nanomaterial: An Experimental Study.

Cadmium (Cd) is a harmful element to human health and biodiversity. The removal of Cd from groundwater is of great significance to maintain the environmental sustainability and biodiversity. In this work, a novel low-temperature roasting associated with alkali was applied to synthesize an eco-friendly adsorbent using coal fly ash. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray fluorescence, and X-ray photoelectron spectroscopy were applied to analyze the physical and chemical characteristics of the adsorbent. The experiments show that a significant improvement in specific surface area and activity of adsorbent was observed in this study. The functional groups of Na-O and Fe-O were verified to be beneficial in the removal of Cd2+. The material capacity to adsorb Cd2+ was considerably improved, and the maximum uptake capacity was 61.8 mg g-1 for Cd2+ at 25 °C. Furthermore, pH and ionic strength play critical roles in the adsorption process. The Langmuir and pseudo-second-order models can appropriately describe the adsorption behavior, and the enhanced adsorption ability of Cd2+ by modified coal fly ash was attributed to ion-exchange, co-precipitation, and complexation. Higher sorption efficiency was maintained after two regeneration cycles. These results offer valuable insights to develop high-performance adsorbent for Cd2+ removal.

Tobacco RING E3 Ligase NtRFP1 Mediates Ubiquitination and Proteasomal Degradation of a Geminivirus-Encoded ßC1.

The ßC1 protein encoded by the Tomato yellow leaf curl China virus-associated betasatellite functions as a pathogenicity determinant. To better understand the molecular basis whereby ßC1 functions in pathogenicity, a yeast two-hybrid screen of a tobacco cDNA library was carried out using ßC1 as the bait. The screen revealed that ßC1 interacts with a tobacco RING-finger protein designated NtRFP1, which was further confirmed by the bimolecular fluorescence complementation and co-immunoprecipitation assays in Nicotiana benthamiana cells. Expression of NtRFP1 was induced by ßC1, and in vitro ubiquitination assays showed that NtRFP1 is a functional E3 ubiquitin ligase that mediates ßC1 ubiquitination. In addition, ßC1 was shown to be ubiquitinated in vivo and degraded by the plant 26S proteasome. After viral infection, plants overexpressing NtRFP1 developed attenuated symptoms, whereas plants with silenced expression of NtRFP1 showed severe symptoms. Other lines of evidence showed that NtRFP1 attenuates ßC1-induced symptoms through promoting its degradation by the 26S proteasome. Taken together, our results suggest that tobacco RING E3 ligase NtRFP1 attenuates disease symptoms by interacting with ßC1 to mediate its ubiquitination and degradation via the ubiquitin/26S proteasome system.

Meta-analysis of the safety and factors contributing to complications of MS-TRAM, DIEP, and SIEA flaps for breast reconstruction.

BACKGROUND: Muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM), deep inferior epigastric perforator (DIEP), and superficial inferior epigastric artery (SIEA) flaps have been increasingly adopted for breast reconstruction. However, their safety, patient satisfaction with them, and factors contributing to complications are not well understood. METHODS: PubMed, MEDLINE, EMBASE, and The Cochrane Library were searched to identify eligible studies for inclusion in our analysis. The complication rates of and patient satisfaction rates with the flaps were measured as the outcome, and factors contributing to complications and patient satisfaction were also studied. The data were extracted, and pooled relative risks (RRs) and 95 % confidence intervals (CIs) were calculated. RESULTS: Thirteen studies involving 1,843 patients met the inclusion criteria. The results of the meta-analysis showed that patients with MS-TRAM had a higher rate of abdominal hernias (RR 2.354, 95 % CI 1.154-4.802, P = 0.019) and a lower rate of fat necrosis (RR 0.502, 95 % CI 0.347-0.727, P = 0.000) than patients with DIEP. In addition, there was no significant difference between MS-TRAM and DIEP with respect to other complications (P > 0.05), between MS-TRAM and DIEP with respect to patient satisfaction (P = 0.923), and between DIEP and SIEA with respect to complication rates (P = 0.377). The complication rates of MS-TRAM, DIEP, and SIEA were 25.6, 27.9, and 26.7 %, respectively. Diabetes mellitus (P = 0.078) influenced the complication rate of MS-TRAM, and obesity (P = 0.086) and diabetes mellitus (P = 0.110) were the potential factors correlated with complications with DIEP flaps. CONCLUSION: There were no obvious differences in the overall incidence of complications between MS-TRAM and DIEP and between DIEP and SIEA. In addition, the patient satisfaction rates of MS-TRAM and DIEP were similar. However, MS-TRAM showed a higher rate of abdominal hernias and a lower rate of fat necrosis than DIEP. Obesity and diabetes mellitus were potential factors associated with the incidence of complications. Additional multicenter, large-sample-size, randomized controlled trials with long-term follow-up visits are necessary. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .