Salinity-dependent aquatic life criteria of inorganic mercury in coastal water and its ecological risk assessment.

Mercury (Hg) is one of the most toxic pollutants to aquatic organisms. The influence of salinity on Hg toxicity, an important factor restricting the development of global marine aquatic life criteria (ALC), is unclear. Therefore, mercury toxicity data were corrected based on salinity using the aggregate slope method, and the ALC values were derived. Short-term aquatic life criteria (SALC) and long-term aquatic life criteria (LALC) were derived using the species sensitivity distribution method based on Log-logistic, Log-normal, Burr III, Gumbel, and Weibull models. The hazard quotient (HQ) and joint probability curve (JPC) methods were used to evaluate the ecological risk of Hg in the coastal waters of China. The results showed that the SALC and LALC of Hg in the coastal waters of China were 2.21 and 0.54 µg/L. The toxicity data and salinity were positively correlated for Chordate and Arthropoda and negatively correlated for Mollusca. The SALC values increased by approximately 75%, with salinities ranging from 10 to 20 ppt. A slight peak in the SALC at mid-salinities was also observed. The ecological risk assessment of Hg in China's coastal waters showed that attention should be paid to Hg pollution in the Bohai Sea and East China Sea, especially the ecological risk of Hg to crustacean organisms. This study could promote the development of water quality criteria for coastal waters and provide a technical reference for mercury management in the coastal waters of China.

Cumulative health risk in children and adolescents exposed to bis(2-ethylhexyl) phthalate (DEHP).

Bis(2-ethylhexyl) phthalate (DEHP) has been widely concerned owing to its widespread detection and endocrine disrupting effect. Nevertheless, systematic analysis and evaluation of the current status of DEHP contamination are still insufficient for children and adolescents. Dietary exposure and nondietary exposure to DEHP were investigated to estimate the total average daily dose (ADD). The top three contributors were dust exposure, edible oil and vegetable intake. Dietary intake contributed highly (70%) to daily exposure to DEHP. By analyzing the monitoring data on DEHP exposure, the cumulative health risks of DEHP were assessed for different age groups of children and adolescents in East China. The probability distributions of noncarcinogenic and carcinogenic risks were determined by Monte Carlo simulation. The results showed that the risk level reduced with age. The predicted mean noncarcinogenic and carcinogenic risks for all age groups exceeded the acceptable level, indicating that the general population would be at high risk by DEHP overexposure. Schoolchildren at ages 6∼<9 were more susceptible to DEHP exposure, with a 30% possibility of exceeding the safety limit Based on these results, gradual banning and restriction should be carried out to decrease DEHP contamination and potential health risks.

Universal window size-dependent transition of correlations in complex systems.

Correlation analysis serves as an easy-to-implement estimation approach for the quantification of the interaction or connectivity between different units. Often, pairwise correlations estimated by sliding windows are time-varying (on different window segments) and window size-dependent (on different window sizes). Still, how to choose an appropriate window size remains unclear. This paper offers a framework for studying this fundamental question by observing a critical transition from a chaotic-like state to a nonchaotic state. Specifically, given two time series and a fixed window size, we create a correlation-based series based on nonlinear correlation measurement and sliding windows as an approximation of the time-varying correlations between the original time series. We find that the varying correlations yield a state transition from a chaotic-like state to a nonchaotic state with increasing window size. This window size-dependent transition is analyzed as a universal phenomenon in both model and real-world systems (e.g., climate, financial, and neural systems). More importantly, the transition point provides a quantitative rule for the selection of window sizes. That is, the nonchaotic correlation better allows for many regression-based predictions.

Human health ambient water quality criteria and risk assessment of pentachlorophenol in Poyang Lake Basin, China.

Pentachlorophenol (PCP) has been widely used as an insecticide for killing oncomelania (the intermediate host of schistosome) in China and leads to severe environmental contamination. Poyang Lake, as the largest freshwater lake and bird habitat in China, was once a schistosomiasis epidemic area. In this study, the concentrations of PCP in water and aquatic products from Poyang Lake were determined and analyzed, and then the human health ambient water quality criteria (AWQC) was derived based on native parameters of Poyang Lake basin. Finally, a comprehensive analysis of the health risks of drinking water and different types of aquatic products consumption was carried out. The results showed that PCP concentrations were ranged from 0.01 to 0.43 µg/L in surface water and 3.90 to 85.95 µg/kg in aquatic products. Due to the carcinogenicity of PCP, the human health AWQC for PCP are 0.02 µg/L for consumption of water and organisms and 0.03 µg/L for consumption of organisms only. Deterministic and probabilistic risk analysis indicated that the non-carcinogenic risk of PCP were acceptable in Poyang Lake, while the carcinogenic risk cannot be ignored. The health risks of PCP caused by aquatic products consumption were higher than that by drinking water. The percentages of acceptable risk for the population in Poyang Lake Basin were 99.95% at acceptable level of 10-4. Based on the sensitivity analysis, the impact of PCP concentrations on health risk values ranged from 53 to 82%. The study provided valuable information for regional water quality criteria development and water quality assessment.

Ammonia spatiotemporal distribution and risk assessment for freshwater species in aquatic ecosystem in China.

Ammonia has been of concern for its high toxicity to aquatic species and frequent detection in waters worldwide. This study calculated the national aquatic life criteria for ammonia in China. The temporal and spatial distributions were investigated and the multi-tier ecological risks were assessed for ammonia and un-ionized ammonia (NH3) during 2014-2018 based on a total of 18989 ammonia monitoring data from 110 monitoring sites in seven river basins. The sensitivity comparison of different species taxa to ammonia showed that Perciformes fish should be listed as a priority protected species in the derivation of ammonia criteria. The participation of introduced aquaculture species have no significant impact on the final criteria values (t-test, p > 0.05). The final criterion maximum concentration (CMC) and criterion continuous concentration (CCC) were 10.24 and 3.31 mg/L for ammonia (pH 7.0 and 20 °C). The interannual variation showed that decreasing trends were observed for ammonia and NH3 pollutions in the past five years. However, the increasing trends were observed for ammonia in Liao River basin, for NH3 in Yangtze River and Pearl River basins (2014-2018). The significant seasonal and geographical differences of ammonia and NH3 pollution were found. Moreover, the pollutions of ammonia and NH3 in some monitoring points of Huai River, Yellow River and Songhua River basins at the provincial borders were significant. The result of ecological risk assessment showed that the average exceedance probability for 5% affected species by NH3 in long-term exposure was 28.96% in the past five years.

A quantification method of non-failure cascading spreading in a network of networks.

The cascading spreading process in social and economic networks is more complicated than that in physical systems. These networks' multiple nodes and edges increase their structural complexity and recoverability, enabling the system to lose partial functionality rather than completely fail. However, these phenomena in social and economic networks introduce challenges to the existing network robustness models, where a node is either in a functional state or a failed state. This research uses a network of networks (NoN) to simulate multiple types of nodes and edges. A non-failure cascading process is utilized to model the nodes' self-adaptation and recoverability. The main contribution of this research is proposing a spreading model to extend the non-failure cascading process to the NoN, which can be used in predicting real-world system damage suffering from special events. The case study of this research evaluated the effect degree of crude oil trade changes on each sector from 2015 to 2016.

Structural decomposition analysis of global carbon emissions: The contributions of domestic and international input changes.

Finding the essential factors driving carbon emissions is vital for the carbon reduction policy-making. Different from the existing research, this paper studied the separate influence of internal and external input structural changes on global carbon emissions. We applied structural decomposition analysis (SDA) to decompose the global carbon emission change into six factors: namely, the carbon emission intensity, the domestic input structure, the international input structure, consumption pattern, consumption volume and population. The results firstly showed that the contributions of different factors to global carbon emissions changed over time. In recent five years, structural changes of domestic inputs became the principle driver of decrease in global carbon emissions. Secondly, the results showed that there were significant differences for countries in their factors for carbon emissions. In India and Russia, domestic input structural change was the major contributor to the decrease in carbon emissions. In Japan and Germany, the most important factor for the increase in carbon emissions was the international input structure. Finally, the results showed the factors for carbon emission changes were correlated to economic development. The international input structural changes significantly increased carbon emissions in high-income countries. Our findings suggested that some countries such as India and Russia, improving the usage efficiency of domestic carbon-intensive products would help reducing carbon emissions. For most high-income countries such as Japan and Germany, they should reduce the dependence on the imported carbon-intensive products by turning the external input sources to countries with technology advantages. In addition, technology exportation of high-income countries would also be beneficial for the global carbon reduction.

Secretion of human soluble programmed cell death protein 1 by chimeric antigen receptor-modified T cells enhances anti-tumor efficacy.

BACKGROUND AIMS: Chimeric antigen receptor (CAR) T cells have achieved favorable responses in patients with hematologic malignancies, but the outcome has been far from satisfactory in the treatment of tumors with high expression of immunosuppressive molecules. To overcome this limitation, we modified CAR T cells to secrete types of human soluble programmed cell death protein 1 (PD-1) called sPD-1 CAR T cells. METHODS: To compare the effector function between second (conventional second-generation CAR targeting CD19) and sPD-1 CAR T cells, we measured cytotoxicity, cytokine secretion and activation markers incubated with or without tumor cells expressing CD19 and/or programmed cell death ligand 1 (PD-L1). Furthermore, the anti-tumor efficacy of second and sPD-1 CAR T cells was determined using an NSG mouse model bearing NALM-6-PD-L1. Finally, the underlying mechanism was investigated by metabolic parameters and RNA sequencing analysis of different CAR T cells. RESULTS: Compared with second CAR T cells, sPD-1 CAR T cells enhanced killing efficiency toward CD19+PD-L1+ tumor cells in vitro. Furthermore, sPD-1 CAR T cells reduced the tumor burden and prolonged overall survival of the NSG (NOD-SCID-IL2rg) mice bearing NALM-6-PD-L1. To explore the effect of soluble PD-1 on CAR T cells, we found that sPD-1 CAR T cells exhibited higher levels of activation and ameliorative profiles of differentiation, exhaustion, glycolysis and apoptosis. CONCLUSIONS: With constitutive soluble PD-1 secretion, sPD-1 CAR T cells have tended to eradicate tumors with a high expression of PD-L1 more effectively than second CAR T cells. This may be due to soluble PD-1 enhancing apoptosis resistance, aerobic metabolism and a more "stem" differentiation of CAR T cells. Overall, our study presents a feasible strategy to increase the efficacy of CAR T cells.

Development of aquatic life criteria for tonalide (AHTN) and the ecological risk assessment.

AHTN (tonalide) is a polycyclic musk that is widely used as fragrance additive in numerous consumer products. AHTN is of great worldwide concern owing to its adverse effects on aquatic organisms and frequent detection in both domestic and foreign aquatic environments. Therefore, derivation of the aquatic life criteria for AHTN exposure is urgently needed. In this work, AHTN toxicity data for eight Chinese native freshwater organisms were used to derive a criterion maximum concentration of 59.39 µg/L and a criterion continuous concentration of 22.43 µg/L using United States Environmental Protection Agency guidelines. Toxicity tests showed that the annelid L. hoffmeisteri and the amphibian R. nigromaculata were the least and most sensitive species to AHTN, respectively. The sensitivity of the planktonic crustacean D. magna to AHTN obviously differed from that of the benthic crustacean M. nipponense. The AHTN and HHCB correlation analysis exhibited a strong positive linear correlation (R2 = 0.8622) in water. The ecological risk assessment showed that AHTN and HHCB posed a higher risk in foreign surface waters than Chinese waters, but a lower risk in foreign wastewater treatment plant effluent than in China. The ecological risks of AHTN and HHCB in most surveyed water bodies of various countries were at acceptable levels, with a few exceptions.

Aquatic life criteria derivation and ecological risk assessment of DEET in China.

N,N-diethyl-meta-toluamide (DEET) is the most widely used active ingredient in commercial insect repellents. In addition to its adverse effects in insects, DEET can affect non-target organisms in surface water systems. Nevertheless, the aquatic life criteria of DEET are not available. This study conducted both acute and chronic toxicity tests on DEET in native Chinese aquatic species, and derived its criterion maximum concentration (CMC) and criterion continuous concentration (CCC). The determined CMC and CCC of DEET were 21.53 and 0.52 mg/L, respectively. The toxicity data indicated that DEET exposure posed a higher toxicity to some algae than other aquatic species. Compared with other insect repellents, DEET exposure posed a moderate toxicity to aquatic species. Therefore, the exposure concentration of DEET in Chinese surface water was collected to assess the potential ecological risk. The preliminary ecological risk assessment showed that DEET posed negligible risk to aquatic ecosystems in China. However, considering its toxic effects on the growth and reproduction to aquatic organisms, the ecological risk posed by DEET is worth further concern.

Dynamic heteroscedasticity of time series interpreted as complex networks.

Heteroscedasticity of time series is an important issue addressed in relation to the nonlinearity and complexity of time series. Previous studies have focused on time series heteroscedasticity during a long-term period but have rarely analyzed it from a nonlinear dynamic perspective. This paper proposes a new model for converting a time series into a complex network. Our proposed model can examine not only the heteroscedasticity of a short-term series but also the dynamic evolution process of this heteroscedasticity. Using four typical crude oil time series as sample data, we construct four networks. A network node denotes the types of fluctuation patterns corresponding to the symbolization of the heteroscedastic features of a short-term fluctuation series based on the autoregressive generalized autoregressive conditional heteroscedasticity model, and a weighted edge represents the evolution direction and frequency between two patterns. Our findings show that the choice of the length of a short-term period depends on the diversity of these patterns. The identification of the nodes with greater out-strength or greater betweenness centrality can help us to understand the different roles of fluctuation patterns in the evolution process. We propose a method for predicting the most probable target nodes from a source node. The analysis of clustering effects can help in detecting the fluctuation patterns between different clusters. This paper investigates the evolution dynamic mechanism of the heteroscedastic features of a short-term time series, which can help researchers and investors deeply understand the dynamic process of time series.

Evaluation and characteristics of immunological adjuvant activity of purified fraction of Albizia julibrissin saponins.

PURPOSE: The purified fraction of Albizia julibrissin saponins (AJSAF) was evaluated and characterized for the adjuvant activity on porcine reproductive and respiratory syndrome virus (PRRSV) vaccine. METHODS: The effects of AJSAF on serum PRRSV N protein-specific antibody titers, splenocyte proliferation, natural killer (NK) cell activity, mRNA expression of cytokines and transcription factors, secretion of cytokines, T cells response in splenocytes, as well as delayed type hypersensitivity (DTH) in the mice immunized PRRSV vaccine were determined by ELISA, MTT assay, flow cytometry and quantitative real-time PCR (qRT-PCR). RESULTS: AJSAF not only significantly enhanced the serum PRRSV N protein-specific IgG, IgG1, IgG2a and IgG2b antibody titers in the mice immunized with PRRSV CH-1R modified live vaccine (CH-1R MLV), inactivated vaccine (CH-1R IAV), and highly pathogenic JXA1-R modified live vaccine (JXA1-R MLV), but promoted the concanavalin A (Con A)-, lipopolysaccharide (LPS)- and PRRSV N protein-stimulated splenocyte proliferation, the activities of NK cells and delayed type hypersensitivity (DTH) in the mice immunized CH-1R MLV. AJSAF also remarkably induced the production of both Th1 (IFN-γ) and Th2 (IL-10) cytokines, and up-regulated the mRNA expression levels of Th1 cytokines (IFN-γ and IL-2) and transcription factors (T-bet and STAT4) as well as Th2 cytokines (IL-4 and IL-10) and transcription factors (GATA-3 and STAT6) in splenocytes from the CH-1R MLV-immunized mice. Furthermore, AJSAF markedly increased the frequencies of PRRSV N protein-specific Th1 (INF-γ+ and IL-2+) and Th2 (IL-4+ and IL-10+) CD4 T cells as well as Tc1 (INF-γ+ and IL-2+) and Tc2 (IL-4+ and IL-10+) CD8 T cells in splenocytes from the CH-1R MLV-immunized mice. CONCLUSIONS: Our results demonstrated that AJSAF had a potential to enhance and improve immune responses and elicit both Th1/Th2 and Tc1/Tc2 response to PRRSV vaccine, and that AJSAF would be a promising adjuvant candidate for PRRSV vaccine.

Exposure and ecological risk of phthalate esters in the Taihu Lake basin, China.

The environmental spatial distribution and exposure risk of 6 phthalate esters (PAEs) including dimethyl phthalate (DMP), diethyl phthalate (DEP), butyl benzyl phthalate (BBP), di-n-octyl phthalate (DnOP), bis(2-ethylhexyl) phthalate (DEHP), and dibutyl phthalate (DBP), in surface water and sediment of Taihu Lake basin, China, were investigated at 65 sites. The exposure concentrations of 6 PAEs (∑6PAEs) detected in the samples spanned a range of 0.740-13.0 µg/L in surface water and 5.15-20.9 mg/kg in sediment. DBP and DEHP were the predominant compounds in surface water, with mean concentrations of 1.59 µg/L and 1.29 µg/L, respectively. DnOP was the predominant compound in sediment with mean concentration of 7.41 mg/kg. Ecological risk assessment was conducted by the hazard quotient method in which the predicted no effect concentration (PNEC) was derived from the species sensitivity distribution (SSD) curve. The results showed that DEHP in water phase posed a higher environmental risk than the other PAEs, while the DEP in sediment posed a high risk to the aquatic system. The study contributed to better understanding the presence of PAEs in Taihu Lake basin and provided valuable information for managing and controlling PAEs pollution.

Comprehensive assessment of copper's effect on marine organisms under ocean acidification and warming in the 21st century.

Copper (Cu) has sparked widespread global concern as one of the most hazardous metals to aquatic animals. Ocean acidification (OA) and warming (OW) are expected to alter copper's bioavailability based on pH and temperature-sensitive effects; research on their effects on copper on marine organisms is still in its infancy. Therefore, under representative concentration pathways (RCP) 2.6, 4.5, and 8.5, we used the multiple linear regression-water quality criteria (MLR-WQC) method to assess the effects of OA and OW on the ecological risk posed by copper in the Ocean of East China (OEC), which includes the Bohai Sea, Yellow Sea, and East China Sea. The results showed that there was a positive correlation between temperature and copper toxicity, while there was a negative correlation between pH and copper toxicity. The short-term water quality criteria (WQC) values were 1.53, 1.41, 1.30 and 1.13 µg·L-1, while the long-term WQC values were 0.58, 0.48, 0.40 and 0.29 µg·L-1 for 2020, 2099-RCP2.6, 2099-RCP4.5 and 2099-RCP8.5, respectively. Cu in the OEC poses a moderate ecological risk. Under the current copper exposure situation, strict intervention (RCP2.6) only increases the ecological risk of copper exposure by 20 %, and no intervention (RCP8.5) will increase the ecological risk of copper exposure by nearly double. The results indicate that intervention on carbon emissions can slow down the rate at which OA and OW worsen the damage copper poses to marine creatures. This study can provide valuable information for a comprehensive understanding of the combined impacts of climate change and copper on marine organisms.

A comprehensive review of the effects of salinity, dissolved organic carbon, pH, and temperature on copper biotoxicity: Implications for setting the copper marine water quality criteria.

In recent years, there has been a growing concern about the ecological hazards associated with copper, which has sparked increased interest in copper water quality criteria (WQC). The crucial factors affecting the bioavailability of copper in seawater are now acknowledged to be salinity, dissolved organic carbon (DOC), pH, and temperature. Research on the influence of these four water quality parameters on copper toxicity is rapidly expanding. However, a comprehensive and clear understanding of the relevant mechanisms is currently lacking, hindering the development of a consistent international method to establish the seawater WQC value for copper. As a response to this knowledge gap, this study presents a comprehensive summary with two key focuses: (1) It meticulously analyzes the effects of salinity, DOC, pH, and temperature on copper toxicity to marine organisms. It takes into account the adaptability of different species to salinity, pH and temperature. (2) Additionally, the study delves into the impact of these four water parameters on the acute toxicity values of copper on marine organisms while also reviewing the methods used in establishing the marine WQC value of copper. The study proposed a two-step process: initially zoning based on the difference of salinity and DOC, followed by the establishment of Cu WQC values for different zones during various seasons, considering the impacts of water quality parameters on copper toxicity. By providing fundamental scientific insights, this research not only enhances our understanding and predictive capabilities concerning water quality parameter-dependent Cu toxicity in marine organisms but also contributes to the development of copper seawater WQC values. Ultimately, this valuable information facilitates more informed decision-making in marine water quality management efforts.

Predicting multiple observations in complex systems through low-dimensional embeddings.

Forecasting all components in complex systems is an open and challenging task, possibly due to high dimensionality and undesirable predictors. We bridge this gap by proposing a data-driven and model-free framework, namely, feature-and-reconstructed manifold mapping (FRMM), which is a combination of feature embedding and delay embedding. For a high-dimensional dynamical system, FRMM finds its topologically equivalent manifolds with low dimensions from feature embedding and delay embedding and then sets the low-dimensional feature manifold as a generalized predictor to achieve predictions of all components. The substantial potential of FRMM is shown for both representative models and real-world data involving Indian monsoon, electroencephalogram (EEG) signals, foreign exchange market, and traffic speed in Los Angeles Country. FRMM overcomes the curse of dimensionality and finds a generalized predictor, and thus has potential for applications in many other real-world systems.

Comprehensive effects of salinity, dissolved organic carbon and copper on mortality, osmotic regulation and bioaccumulation of copper in Oryzias melastigma.

Cu, as an essential and toxic element, has gained widespread attention. Both salinity and dissolved organic carbon (DOC) are known to influence Cu toxicity in marine organisms. However, the intricate interplay between these factors and their specific influence on Cu toxicity remains ambiguous. So, this study conducted toxicity tests of Cu on Oryzias melastigma. The experiments involved three salinity levels (10, 20, and 30 ppt) and three DOC levels (0, 1, and 5 mg/L) to comprehensively investigate the underlying mechanisms of toxicity. The complex toxic effects were analyzed by mortality, NKA activity, net Na+ flux and Cu bioaccumulation in O. melastigma. The results indicate that Cu toxicity is notably influenced by both DOC and salinity. Interestingly, the discernible variation in Cu toxicity across different DOC levels diminishes as salinity levels increase. The presence of DOC enhances the impact of salinity on Cu toxicity, especially at higher Cu concentrations. Additionally, Visual MINTEQ was utilized to elucidate the chemical composition of Cu, revealing that DOC had a significant impact on Cu forms. Furthermore, we observed that fluctuations in salinity lead to the inhibition of Na+/K+-ATPase (NKA) activity, subsequently hindering the inflow of Na+. The effects of salinity and DOC on the bioaccumulation of copper were not significant. The influence of salinity on Cu toxicity is mainly through its effect on the osmotic regulation and biophysiology of O. melastigma. Additionally, DOC plays a crucial role in the different forms of Cu. Moreover, DOC-Cu complexes can be utilized by organisms. This study contributes to understanding the mechanism of copper's biological toxicity in intricate marine environments and serves as a valuable reference for developing marine water quality criteria for Cu.

CO2 emissions are first aggravated and then alleviated with economic growth in China: a new multidimensional EKC analysis.

CO2 emissions have become a topical issue worldwide, but few studies have considered the spatial effect of income on carbon emissions and explored the relationship between CO2 emissions and income by establishing direct, indirect, and total environmental Kuznets curves (EKCs). Using an annual panel dataset collected over the 1997-2017 period in China, this study first analyzed the spatiotemporal evolutionary process of CO2 emissions and subsequently developed direct, indirect, and total EKC-based spatial Durbin model (SDM) and partial derivative approach. These results indicate that, first, CO2 emissions have characteristic positive spatial autocorrelation, with gravity centers that have shifted westward. Second, the direct EKC forms a line, while the total EKC resembles a lying-S shape as well as the total EKC, which indicates that compared to local economic growth, neighboring growth plays a very different role in impacting local CO2 emissions. Furthermore, neighboring economic growth seems to have stronger impacts on local emissions, and the turning point of the total EKC comes much earlier than that of the conventional EKC due to the spillover effects of economic growth. Finally, the growth of the population, as well as the rise of energy intensity, can stimulate CO2 emissions in both local and neighboring regions. Industrialization seems to have a nonsignificant impact on emission changes due to the offsetting effects of the positive direct and negative indirect impacts of the share of secondary industry. Improvements in local urbanization may lead to an increase in emissions, while neighboring improvements may have stronger restricting effects; thus, urbanization improvement is beneficial to emissions reduction. This study provides more scientific information from both local and neighboring perspectives, which may differ from conventional results but still be beneficial for emissions reduction policy-makers to introduce corresponding measures.

Ecotoxicity stress and bioaccumulation in Eisenia fetida earthworms exposed to vanadium pentoxide in soil.

As an important commercial form of vanadium, vanadium pentoxide (V2O5) is widely used in various modern industries, and its environmental impacts and ecotoxicity have been extensively studied. In this research, the ecotoxicity of V2O5 to earthworms (Eisenia fetida) in soil was tested by exposure to V2O5 at a series of doses, and biochemical response indices, such as the superoxide dismutase (SOD) and catalase (CAT) enzyme activity and malondialdehyde (MDA) content, were analysed to determine the mechanism by which antioxidant enzymes respond to V2O5 exposure. The bioaccumulation factor (BAF) of vanadium pentoxide in the earthworms and soil was also measured to explore the bioaccumulation process of V2O5 in the test period. The results showed that the acute and subchronic lethal toxicity values of V2O5 towards E. fetida were 21.96 mg/kg (LC50, 14 days) and 6.28 mg/kg (LC10, 28 days), respectively. For the antioxidant enzymes, SOD and CAT were synchronously induced or inhibited within the time period, and the enzyme activity had a dose-effect relationship with the V2O5 concentration. MDA analysis indicated that lipid peroxidation in earthworms mainly occurred at the early stage and was eliminated slowly in the later stage during the test time. In addition, the BAFs were much less than 1, which indicated that V2O5 did not easily accumulate in earthworms, and the BAF was positively correlated with the exposure time and negatively linearly correlated with the V2O5 concentration in the soil. These results indicated that the bioconcentration and metabolic mechanism of V2O5 in earthworms differed with the different exposure concentrations, and bioaccumulation became balanced after 14-28 days in earthworms exposed to a relatively lower dose of V2O5. The analysis of the integrated biomarker response (IBR) index indicated that the trends of IBR values were positively related to the changing V2O5 concentration, and the IBR index could reflect the organism's sensitivity to the external stimulus of V2O5. The toxicity of V2O5 is mainly caused by V5+, which is also an important factor in formulating guidelines regarding vanadium levels in soil, and the test earthworm species (Eisenia fetida) is a sensitive biological indicator for risk assessments of vanadium oxidation in the soil.

Scaling up production of recombinant human basic fibroblast growth factor in an Escherichia coli BL21(DE3) plysS strain and evaluation of its pro-wound healing efficacy.

Introduction: Human basic fibroblast growth factor (hbFGF) is a highly valuable multifunctional protein that plays a crucial role in various biological processes. In this study, we aim to accomplish the scaling-up production of mature hbFGF (146aa) by implementing a high cell-density fermentation and purification process on a 500-L scale, thereby satisfying the escalating demands for both experimental research and clinical applications. Methods: The hbFGF DNA fragment was cloned into a mpET-3c vector containing a kanamycin resistance gene and then inserted into Escherichia coli BL21 (DE3) plysS strain. To optimize the yield of hbFGF protein, various fermentation parameters were systematically optimized using BOX-Behnken design and further validated in large-scale fermentation (500-L). Additionally, a three-step purification protocol involving CM-Sepharose, heparin affinity, and SP-Sepharose column chromatography was developed to separate and purify the hbFGF protein. Isoelectric focusing electrophoresis, MALDI-TOF/MS analysis, amino acid sequencing, CD spectroscopy, and Western blotting were performed to authenticate its identity. The biological efficacy of purified hbFGF was evaluated using an MTT assay as well as in a diabetic deep second-degree scald model. Results: The engineered strain was successfully constructed, exhibiting high expression of hbFGF and excellent stability. Under the optimized fermentation conditions, an impressive bacterial yield of 46.8 ± 0.3 g/L culture with an expression level of hbFGF reaching 28.2% ± 0.2% was achieved in 500-L scale fermentation. Subsequently, during pilot-scale purification, the final yield of purified hbFGF protein was 114.6 ± 5.9 mg/L culture with RP-HPLC, SEC-HPLC, and SDS-PAGE purity exceeding 98%. The properties of purified hbFGF including its molecular weight, isoelectric point (pI), amino sequence, and secondary structure were found to be consistent with theoretical values. Furthermore, the purified hbFGF exhibited potent mitogenic activity with a specific value of 1.05 ± 0.94 × 106 AU/mg and significantly enhanced wound healing in a deep second-degree scald wound diabetic rat model. Conclusion: This study successfully established a stable and efficient large-scale production process of hbFGF, providing a solid foundation for future industrial production.