Toxicokinetics of selenate in earthworm sub-tissues and potential bio-accessibility assessment of earthworm-derived selenium.

Selenium (Se) pollution is mainly caused by anthropogenic activities, and the resulting biosecurity concerns have garnered significant attention in recent years. Using one-compartmental toxicokinetic (TK) modelling, this study explored the kinetic absorption, sub-tissue distribution, and elimination processes of the main Se species (selenate, Se(VI)) in the cultivated aerobic soil of the earthworm Eisenia fetida. The bio-accessibility of earthworm-derived Se was assessed using an in vitro simulated gastrointestinal digestion test to evaluate its potential trophic risk. The results demonstrated that Se accumulated in the pre-clitellum (PC) and total tissues (TT) of earthworms in a time- and dose-dependent manner. The highest Se levels in the PC, post-clitellum (PoC), and TT were 70.54, 57.93, and 64.26 mg/kg during the uptake phase, respectively. The kinetic Se contents in the earthworms PC and TT were consistent with the TK model but not with PoC. The earthworm TT exhibited a faster uptake (Kus = 0.83-1.02 mg/kg/day) and elimination rate of Se (Kee = 0.044-0.049 mg/kg/day), as well as a shorter half-life time (LT1/2 = 15.88-14.22 days) than PC at low soil Se levels (≤5 mg/kg). Conversely, the opposite trend was observed with higher Se concentrations (10 and 20 mg/kg). These results are likely attributable to the tissue specificity and concentration of the toxicant. Earthworms PC and TT exhibited a higher kinetic Se accumulation factor (BAFk) than steady-state BAF (BAFss), with values ranging from 8 to 24 and 3-13, respectively. Furthermore, the bio-accessibility of earthworm-derived Se to poultry ranged from 66.25 % to 84.35 %. As earthworms are at the bottom of the terrestrial food chain, the high bio-accessibility of earthworm-derived Se poses a potential risk to predators. This study offers data support and a theoretical foundation for understanding the biological footprint of soil Se and its toxicological impacts and ecological hazards.

Selenium toxicity, bioaccumulation, and distribution in earthworms (Eisenia fetida) exposed to different substrates.

Selenium (Se) is an essential microelement for human or animal health. At high concentrations, it can cause Se poisoning. Human activities (such as coal burning and mining) threaten soil biota by mobilizing high levels of Se. We used the earthworm Eisenia fetida as a bio-indicator of environmental pollutants to investigate Se acute toxicity, enrichment, and distribution through exposure tests using filter paper, artificial soil and cow manure. The 24 h- and 48 h-LC50 for the filter paper contact test were 2.7 and 1.52 µg/cm2. In artificial soil test, the 14 d-LC50 and 14 d-biomass inhibition concentration (IC20) were 63.86 and 59.81 mg/kg, respectively. The cow manure resulted in a 2.2- and 2.6-fold higher LC50 and IC20 than artificial soil results, respectively. Earthworms accumulated the largest Se load (89.47 mg/kg) in artificial soil containing 80 mg Se/kg and only accumulated 90.3 mg/kg in cow manure containing 160 mg Se/kg; 46.6-60.59% of the total Se was distributed in the tail of E. fetida. The Se enrichment rate (SERSe) and bioaccumulation factor (BAFSe) scored higher in artificial soil than in cow manure with the same Se concentration exposure, and the highest SERSe was 6.21 and 6.31 mg Se/kg earthworm/d, respectively. The highest BAFSe was 1.49 in artificial soil and 0.75 in cow manure. Our results demonstrate that selenite is more toxic to earthworms living in artificial soil than in cow manure. E. fetida possesses certain Se detoxification mechanisms by distributing Se in the tail.

Ecological risk of copper and zinc and their different bioavailability change in soil-rice system as affected by biowaste application.

A large amount of organic fertilizer application could be accompanied by soil contamination caused by trace heavy metals. A field experiment was carried out in this study to examine the accumulation and availability of copper (Cu) and zinc (Zn) in soil, and their uptake by rice under continuous application of chicken manure, pig manure and sewage sludge. Results showed that after four years of chicken manure, pig manure and sewage sludge application, the soil Cu accumulation rates were 0.15-1.17 mg kg-1 yr-1, 1.01-4.22 mg kg-1 yr-1 and 0.13-1.15 mg kg-1 yr-1, respectively; Zn accumulation rates were 0.54-5.46 mg kg-1 yr-1, 1.51-9.65 mg kg-1 yr-1 and 1.13-10.47 mg kg-1 yr-1, respectively. Compared to the control, the chicken- and pig manure treatments significantly decreased the DTPA-extractable Cu, but increased the DTPA-extractable Zn in soils; thus decreased the Cu contents in rice grain by 2.2-40.6% and increased the grain Zn by 2.6-30.9%, respectively, with increasing application rates and number of years. The addition of sewage sludge significantly increased bioavailability of Zn in soil and its accumulation in rice, while had limited effect on Cu bioavailability. Results suggested that the continuous application of organic fertilizer with elevated Cu and Zn contents at high application rates can induce their accumulation in soil and affect their bioavailability differently.

Polycaprolactone Nanofibers Containing Vascular Endothelial Growth Factor-Encapsulated Gelatin Particles Enhance Mesenchymal Stem Cell Differentiation and Angiogenesis of Endothelial Cells.

During the regeneration of tissues and organs, growth factors (GFs) play a vital role by affecting cell behavior. However, because of the low half-life time and quick degradation of GFs, their stimulations on cells are relatively short and discontinuous. In this study, a releasing scaffold platform, consisting of polycaprolactone (PCL) nanofibers and vascular endothelial growth factor (VEGF)-encapsulated gelatin particles, was developed to extend the influence of GFs on mesenchymal stem cells (MSCs) and endothelial cells (ECs). The results showed that this kind of scaffold can direct the differentiation of MSCs to ECs and maintain the stability of the tubular structure, an indicator of the angiogenesis ability of ECs, for an extended period of time. Therefore, the results suggest the potential application of PCL/VEGF-encapsulated gelatin particles (PCL/VGPs) as a growth factor (GF)-releasing scaffold platform in vascular tissue engineering.

Polyethylene-glycol-coated gold nanoparticles improve cardiac function after myocardial infarction in mice.

Gold nanoparticles (AuNPs) are widely used for drug delivery because of their unique biological properties, such as their safety and ability to prolong drug action. Some studies have demonstrated that AuNPs accumulate in the heart, especially during pathological processes. Therefore, it is very important to understand the effect of AuNPs on the heart. Myocardial infarction (MI) is a major cause of morbidity and mortality; however, the effect of AuNPs on MI remains unclear. In the present study, we carried out a comprehensive evaluation of AuNPs on acute MI. The results showed that AuNPs accumulated in infarcted hearts, decreased infarction size, improved systolic function, and inhibited cardiac fibrosis and TNF-α accumulation. Our work indicated that AuNPs have cardioprotective effects and can be used in drug delivery systems for the treatment of cardiac diseases.

Structural equation model of the relationship between metals in contaminated soil and in earthworm (Metaphire californica) in Hunan Province, subtropical China.

Earthworms have the ability to take up heavy metals in soil and partition them in different subcellular compartments. In this study, we used a structural equation model (SEM) to investigate the two-step causal relationship between environmental availability (EA) and environmental bioavailability (EB) of heavy metals (Cd, Cu, Zn, and Pb), as reflected by their levels in soil fractions and in earthworms from field-contaminated areas in Southern China. In the SEM, the correlation between EA and EB reflected the bioavailability of Cd, Zn, and Pb. For Cd, the causal relationship between the latent variables EA and EB was reflected by DTPA fractions in soil as well as by earthworm internal and subcellular cytosol fractions. The extractable and oxidizable fractions of Zn in soil influenced Zn concentrations in the cytosol and debris. The DTPA and reducible Pb fractions were bioavailable to earthworm internal Pb concentrations and those in cytosol fractions. These results implied that the DTPA, extractable, oxidizable, or reducible fractions of different metals could be the bioavailable sources to earthworm internal metals and partitioned in their subcellular compartments.

Effects of continuous fertilization on bioavailability and fractionation of cadmium in soil and its uptake by rice (Oryza sativa L.).

A four-year field trial was conducted in a rice paddy in southern China to determine the effects of continuous phosphate fertilizer, pig manure, chicken manure, and sewage sludge application on soil Cd accumulation in soil and Cd uptake by rice. The results showed that continuous application of fertilizers with higher Cd levels caused Cd to accumulate and redistribute in various soil fractions. In turn, these effects influenced Cd bioavailability in rice plants. After four years of phosphate fertilizer, pig manure, chicken manure, and sewage sludge application, the annual soil Cd accumulation rates were 0.007-0.032 mg kg-1, 0.005-0.022 mg kg-1, 0.002-0.013 mg kg-1, and 0.032-0.087 mg kg-1, respectively. Relative to the control, the pig- and chicken manure treatments significantly increased soil pH and reduced DTPA-extractable Cd (DTPA-Cd) and the exchangeable Cd fraction (Exc-Cd). In contrast, sewage sludge application significantly increased DTPA-Cd and Cd in all soil fractions. Phosphate fertilization had no significant effect on soil pH, DTPA-Cd, or Exc-Cd. Pearson's correlation coefficients showed that the rice grain Cd levels varied directly with DTPA-Cd, and Exc-Cd but inversely with soil pH. Pig- or chicken manure decreased rice grain Cd content, but sewage sludge increased both soil Cd availability and rice grain Cd uptake. Application of phosphate fertilizer had no significant effect on rice grain Cd content. The continuous use of organic- or phosphate fertilizer with elevated Cd content at high application rates may induce soil Cd accumulation and influence rice grain Cd accumulation.

Influence of metal-contamination on distribution in subcellular fractions of the earthworm (Metaphire californica) from Hunan Province, China.

Earthworms have the ability to accumulate of heavy metals, however, there was few studies that addressed the metals in earthworm at subcellular levels in fields. The distributions of metals (Cd, Cu, Zn, and Pb) in subcellular fractions (cytosol, debris, and granules) of earthworm Metaphire californica were investigated. The relationship between soil metals and earthworms were analyzed to explain its high plasticity to inhabit in situ contaminated soil of Hunan Province, south China. The concentration of Cd in subcellular compartments showed the same pattern as Cu in the order of cytosol > debris > granules. The distribution of Zn and Pb in earthworms indicated a similar propensity for different subcellular fractions that ranked as granules > debris > cytosol for Zn, and granules > cytosol > debris for Pb. The internal metal concentrations in earthworms increased with the soil metals (p<0.05). Significant positive correlations were found between soil Cd and Cd concentrations in cytosol and debris (p<0.01). Moreover, the soil Pb concentration significantly influenced the Pb concentrations in cytosol and debris (p<0.01), similar to that of Cd. The soil Cu concentrations was only associated with the Cu in granules (p<0.05). Soil Zn concentrations correlated with the Zn concentrations in each subcellular fraction (p<0.05). Our results provide insights into the variations of metals partitioning in earthworms at subcellular levels and the relationships of soil metals, which could be one of the detoxification strategies to adapt the long-term contaminated environment.

Environmental impacts and production performances of organic agriculture in China: A monetary valuation.

Organic agriculture has developed rapidly in China since the 1990s, driven by the increasing domestic and international demand for organic products. Quantification of the environmental benefits and production performances of organic agriculture on a national scale helps to develop sustainable high yielding agricultural production systems with minimum impacts on the environment. Data of organic production for 2013 were obtained from a national survey organized by the Certification and Accreditation Administration of China. Farming performance and environmental impact indicators were screened and indicator values were defined based on an intensive literature review and were validated by national statistics. The economic (monetary) values of farming inputs, crop production and individual environmental benefits were then quantified and integrated to compare the overall performances of organic vs. conventional agriculture. In 2013, organically managed farmland accounted for approximately 0.97% of national arable land, covering 1.158 million ha. If organic crop yields were assumed to be 10%-15% lower than conventional yields, the environmental benefits of organic agriculture (i.e., a decrease in nitrate leaching, an increase in farmland biodiversity, an increase in carbon sequestration and a decrease in greenhouse gas emissions) were valued at 1921 million RMB (320.2 million USD), or 1659 RMB (276.5 USD) per ha. By reducing the farming inputs, the costs saved was 3110 million RMB (518.3 million USD), or 2686 RMB (447.7 USD) per ha. The economic loss associated with the decrease in crop yields from organic agriculture was valued at 6115 million RMB (1019.2 million USD), or 5280 RMB (880 USD) per ha. Although they were likely underestimated because of the complex relationships among farming operations, ecosystems and humans, the production costs saved and environmental benefits of organic agriculture that were quantified in our study compensated substantially for the economic losses associated with the decrease in crop production. This suggests that payment for the environmental benefits of organic agriculture should be incorporated into public policies. Most of the environmental impacts of organic farming were related to N fluxes within agroecosystems, which is a call for the better management of N fertilizer in regions or countries with low levels of N-use efficiency. Issues such as higher external inputs and lack of integration cropping with animal husbandry should be addressed during the quantification of change of conventional to organic agriculture, and the quantification of this change is challenging.

Gender-related differences in ß-adrenergic receptor-mediated cardiac remodeling.

Cardiac remodeling is the pathological basis of various cardiovascular diseases. In this study, we found gender-related differences in ß-adrenergic receptor (AR)-mediated pathological cardiac remodeling. Cardiac remodeling model was established by subcutaneous injection of isoprenaline (ISO) for 14 days. Heart rate (HR), mean arterial pressure (MAP), and echocardiography were obtained on 7th and 14th days during ISO administration. Myocardial cross-sectional area and the ratio of heart mass to tibia length (HM/TL) were detected to assess cardiac hypertrophy. Picro-Sirius red staining (picric acid + Sirius red F3B) was used to evaluate cardiac fibrosis. Myocardial capillary density was assessed by immunohistochemistry for von Willebrand factor. Further, real-time PCR was used to measure the expression of ß1-AR and ß2-AR. Results showed that ISO induced cardiac remodeling, the extent of which was different between female and male mice. The extent of increase in cardiac wall thickness, myocardial cross-sectional area, and collagen deposition in females was less than that in males. However, no gender-related difference was observed in HR, MAP, cardiac function, and myocardial capillary density. The distinctive decrease of ß2-AR expression, rather than a decrease of ß1-AR expression, seemed to result in gender-related differences in cardiac remodeling.

Cadmium uptake dynamics and translocation in rice seedling: Influence of different forms of selenium.

Selenium (Se) can alleviate the toxicity of cadmium (Cd), but little is known about its mechanism in Cd uptake and translocation in plants. We investigated the effects of exogenous selenite, selenate, and selenomethionine (SeMet) on Cd uptake and translocation within rice (Oryza sativa L., Zhunliangyou 608) seedlings, and the concentration-dependent uptake kinetics of Cd into rice roots (with or without Se) were determined. The effect of the endogenous Se pool on Cd uptake was also investigated. Results of uptake kinetics showed that selenite slightly promoted Cd influx during 1h of exposure, compared with no selenite addition; Vmax of Cd uptake increased by 13.8% in 10µM selenite treatment; while the presence of selenate had no effect on the influx of Cd. When exposed to Cd (5µM) over 20h (with selenite) or 30h (with selenate or SeMet), Se addition (5µM) decreased Cd uptake and root-to-shoot translocation; after 30h selenite, selenate, or SeMet addition decreased Cd uptake by roots by 28.6%, 17.7% or 12.1%, respectively. Besides, as the selenite levels in the treatment solutions (1µMCd) increased (0, 0.1, 1, and 5µM, Se), Cd uptake and translocation were both significantly reduced, while the inhibitive effect was more significant at lower levels of selenate. Pretreatment of selenite or selenate (5µM) also decreased Cd uptake by 24.9% or 15.7%, and reduced the root-to-shoot transfer factor by 41.4% or 36.2% after 144h of subjection to Cd (5µM), respectively. The presence of selenite decreased Cd content more effectively than did selenate. Our results demonstrated that Se can effectively reduce the Cd translocation from roots to shoots in rice seedlings.

[Application of ICP-mS and AFS to detecting heavy metals in phosphorus fertilizers].

In order to investigate heavy metals in phosphorus fertilizers in China, 159 samples of phosphorus fertilizers including imported fertilizers and domestic fertilizers were collected from fertilizer markets, and the contents of heavy metals were determined by ICP-MS and AFS after microwave digestion. The results showed that the phosphorous fertilizers contained certain amount of heavy metals, and there was great variability in the contents of heavy metals. The mean contents of Cd, Cu, Zn, Cr, Pb, Ni, As and Hg were 0. 77, 35.6, 102.7, 24. 1, 16.6, 15.4, 19.4 and 0. 08 mg kg-1 fertilizer, respectively; based on the calculation of P2O5, the mean contents of above heavy metals were 4. 48, 258. 4, 767. 4, 190. 0, 151.3, 134. 5, 155. 8 and 8. 79 mg kg-1 P2 O5, respectively. The contents of heavy metals Cd, Cr, Pb, As and Hg in the tested samples accord with the ecological index of arsenic, cadmium, lead, chromium and mercury for fertilizers (GB/T 23349-2009), with the exception of Cd in one imported sample of diammonium phosphate and As in one sample of mono-ammonium phosphate. Analyzing the contents of heavy metals in imported fertilizers, the Cd contents in imported fertilizers was ranged from 0. 02 to 27. 2 mg kg-1 fertilizer, the mean and median Cd contents in imported fertilizers were 3. 20 and 0. 41 mg kg-1 fertilizer, respectively. And the Cu, Cr and Hg contents in the imported fertilizers were higher than that of domestic fertilizers, the mean contents of Cu, Cr and Hg in imported fertilizers were 39. 4, 26. 6 and 0. 47 mg kg-1 fertilizer, respectively.

Responses and resistance capacity of Solanum nigrum L. mediated by three ecological category earthworms in metal-[Cd-As-Cu-Pb]-contaminated soils of North China.

Earthworms play vital functions affecting plant growth and metal accumulation from downground to aboveground. Soil metal mobilization may be combined with use of earthworm and hyperaccumulator-Solanum nigrum to improve its remediation efficiency. Understanding the effects of specific-species earthworm belonging to different ecological categories on mechanisms underlying of S. nigrum is critical for metal-polluted remediation. However, seldom studies concerned earthworm-assisted phytoremediation of metal contaminated soil in Northern China. This study investigated the effects of earthworm (Eisenia fetida, Amynthas hupeiensis and Drawida gisti) on S. nigrum with exposure to uncontaminated and [Cd-As-Cu-Pb]-contaminated soil (referred to as S0 and S1) for 60 days, respectively. In S1 soil, A. hupeiensis (anecic) had stronger effects on growth and metal accumulation in the organs (root, stem, and leaf) of S. nigrum than D. gisti (endogeic) and E. fetida (epigeic), attributing to their ecological category. The BAF values of S. nigrum were generally ranking in Cd (0.66-5.13) > As (0.03-1.85) > Cu (0.03-0.06) > Pb (0.01-0.05); the BAFCd values were ranking in leaf (2.34-5.13) > root (1.96-4.14) > stem (0.66-1.33); BAFAs, BAFCu, and BAFPb were root (0.04-1.63) > stem (0.01-0.09) ≈ leaf (0.01-0.06). A. hupeiensis decreased the TF values of S. nigrum from the roots to the shoots. Co-effects of metal stress and earthworm activity on metal uptake by shoots suggested that A. hupeiensis increased the uptake of As, Cu, and Pb (by 56.3 %, 51.5 %, and 16.2 %, p < 0.05), but not Cd, which appeared to remain steady for prolonged durations. Alterations in the integrated biomarker response index version 2 (IBRv2) values demonstrated that A. hupeiensis (12.65) improved the resistance capacity (stimulated GSH, SnGS1, and SnCu-SOD) of S. nigrum under metal-containing conditions, compared with E. fetida and D. gisti (IBRv2 were 9.61 and 9.11). This study may provide insights into the patterns of 'soil-earthworm-plant system' on improving remediation efficiency of S. nigrum, from the perspective of earthworm ecological niche partitioning.

Phosphate additives promote humic acid carbon and nitrogen skeleton formation by regulating precursors and composting bacterial communities.

This study aimed to compare the effect of different phosphate additives including superphosphate (CP) and MP [Mg(OH)2 + H3PO4] on nitrogen conversion, humus fractions formation and bacterial community in food waste compost. The results showed the ratio of humic acid nitrogen in total nitrogen (HA-N/TN) in CP increased by 49 %. Ammonium nitrogen accumulation was increased by 75 % (CP) and 44 % (MP). Spectroscopic techniques proved that phosphate addition facilitated the formation of complex structures in HA. CP enhanced the dominance of Saccharomonospora, while Thermobifida and Bacillus were improved in MP. Structural equation modeling and network analysis demonstrated that ammonium nitrogen can be converted to HA-N and has positive effects on bacterial composition, reducing sugars and amino acids, especially in CP with more clustered network and synergic bacterial interactions. Therefore, the addition of phosphate provides a new idea to regulate the retained nitrogen toward humification in composting.

Reversing skin cancer adversarial examples by multiscale diffusive and denoising aggregation mechanism.

Reliable skin cancer diagnosis models play an essential role in early screening and medical intervention. Prevailing computer-aided skin cancer classification systems employ deep learning approaches. However, recent studies reveal their extreme vulnerability to adversarial attacks - often imperceptible perturbations to significantly reduce the performances of skin cancer diagnosis models. To mitigate these threats, this work presents a simple, effective, and resource-efficient defense framework by reverse engineering adversarial perturbations in skin cancer images. Specifically, a multiscale image pyramid is first established to better preserve discriminative structures in the medical imaging domain. To neutralize adversarial effects, skin images at different scales are then progressively diffused by injecting isotropic Gaussian noises to move the adversarial examples to the clean image manifold. Crucially, to further reverse adversarial noises and suppress redundant injected noises, a novel multiscale denoising mechanism is carefully designed that aggregates image information from neighboring scales. We evaluated the defensive effectiveness of our method on ISIC 2019, a largest skin cancer multiclass classification dataset. Experimental results demonstrate that the proposed method can successfully reverse adversarial perturbations from different attacks and significantly outperform some state-of-the-art methods in defending skin cancer diagnosis models.

Adaptor protein HIP-55-mediated signalosome protects against ferroptosis in myocardial infarction.

Ischemic heart disease is a leading cause of death worldwide. Myocardial infarction (MI) results in cardiac damage due to cell death and insufficient cardiomyocyte self-renewal. Ferroptosis, a novel type of cell death, has recently been shown as a key cause of cardiomyocyte death after MI. However, the complicated regulation mechanisms involved in ferroptosis, especially how ferroptosis is integrated into classical cell survival/death pathways, are still unclear. Here, we discovered that HIP-55, a novel adaptor protein, acts as a hub protein for the integration of the ferroptosis mechanism into the classical AKT cell survival and MAP4K1 cell death pathways for MI injury. The expression of HIP-55 is induced in MI. Genetic deletion of HIP-55 increased cardiomyocyte ferroptosis and MI injury, whereas cardiac-specific overexpression of HIP-55 significantly alleviated cardiomyocyte ferroptosis and MI injury. Mechanistically, HIP-55 was identified as a new AKT substrate. AKT phosphorylates HIP-55 at S269/T291 sites and further HIP-55 directs AKT signaling to negatively regulate the MAP4K1 pathway against MI injury in a site-specific manner. S269A/T291A-mutated HIP-55 (HIP-55AA), which is defective in AKT phosphorylation and significantly decreases the interaction between HIP-55 and MAP4K1, failed to inhibit the MAP4K1/GPX4 ferroptosis pathway. In line with this mechanism, cardiac-specific overexpression of HIP-55WT mice, but not cardiac-specific overexpression of HIP-55AA mice, protected cardiomyocytes against MI-induced ferroptosis and cardiac injury in vivo. These findings suggest that HIP-55 rewired the classical AKT (cell survival) and MAPK (cell death) pathways into ferroptosis mechanism in MI injury. HIP-55 may be a new therapeutic target for myocardial damage.

Organic conversion tea farms can have comparable economic benefits and less environmental impacts than conventional ones-A case study in China.

Lack of experience concerning the organic conversion period and its associated challenges have made it difficult for conventional farmers to convert to organic farming. In this study, using a combined life cycle assessment (LCA) with data envelopment analysis (DEA) approach, we investigated farming management strategies, and environmental, economic, and efficiency impacts of organic conversion tea farms (OCTF, N = 15) compared to conventional (CTF, N = 13) and organic (OTF, N = 14) tea farms in Wuyi County, China for a year-round (2019). We found that the OCTF reduced agricultural inputs (environmental impacts) and applied more manual harvesting (increased added value) to pull through the conversion period. According to the LCA results, OCTF showed a similar integrated environmental impact index compared with OTF but significantly (P < 0.05) lower than CTF at both midpoint and endpoint levels. In terms of economic assessment, OTF showed the significantly highest total revenue (18.7 thousand $ ha-1 yr-1) and profit (13.7 thousand $ ha-1 yr-1) (P < 0.05) among the farm types. In contrast, OCTF and CTF did not show significant differences in relation to these economic indicators (P > 0.05). The total cost and cost-profit ratio did not show significant differences among the three farm types. Considering the DEA analysis, there were no significant differences in the technical efficiency of all farm types. However, the eco-efficiency of OCTF and OTF was significantly higher than that of CTF. Therefore, conventional tea farms can survive the conversion period with competitive economic and environmental benefits. In this regard, policies should promote organic tea cultivation and agroecological practices to enhance the sustainable transformation of tea production systems.

Eisenia fetida impact on cadmium availability and distribution in specific components of the earthworm drilosphere.

Although the potential of vermiremediation for restoring metal-contaminated soils is promising, the effects of earthworms on the availability of soil metals are still debatable. Most previous studies considered the soil as a "whole black box." Mobilization or immobilization of metals are affected by earthworm activities within drilosphere hotspots under different soil conditions, which has not been specifically studied. Therefore, an improved 2D terrarium was designed to study the impact of earthworm activities on cadmium (Cd) fate in the drilosphere hotspots (burrow wall soils, burrow casts, and surface casts) of different artificially spiked Cd treatments (CK: 0 mg kg-1; LM: 1 mg kg-1; and HM: 5 mg kg-1) with different organic amendments (2% and 10%). The results revealed that Cd increased earthworm activities with the highest cast production in HM and the highest burrow length in LM. Earthworms exhibited a stronger tendency to reduce total Cd concentration by 4.48-13.58% in casts of LM soils, while 3.37-5.22% in burrow walls under HM treatments. Overall, earthworms could increase the availability of Cd in casts under all conditions (55.46-121.01%). The organic amendments decreased the total Cd concentration and increased the availability of Cd in the disturbed soil. A higher amount of organic amendment significantly decreased total Cd concentration of the drilosphere by 1.16-5.83% in LM and HM treatments, while increasing DTPA-Cd concentrations in all components by 23.13-55.20 %, 14.63-35.11%, and 3.30-11.41% in CK, LM, and HM treatments, respectively, except for earthworm non-disturbed soil and no-earthworm soil in HM treatments. Redundancy analysis (RDA) revealed that the moisture, pH, and total carbon contents in soil are the main factors affecting Cd bioavailability. In this study, we decoded the "black box" of soil by making it relatively simple to better understand the effects and mechanisms of earthworm activities on soil metal availability and consequently provided comprehensive insights for using earthworms in soil vermiremediation.

Impact of progressively cumulative exposure of AgNPs on earthworms (Eisenia fetida) and implication for eco-toxicological risk assessment.

Hazardous pollutants released into the real environment mostly own long-lasting cumulative characteristics and have progressively negative impacts on organisms, which are always neglected in laboratory toxicological tests. Here in this study, the different ecotoxicity of Ag nanoparticles (AgNPs) on earthworm Eisenia fetida was compared via various endpoints and transcriptional sequencing between the 28-day progressively repeated (from 60 to 80, final 100 mg/kg) and one-step (directly to 100 mg/kg) exposure. The results showed that earthworms under progressively repeated exposure showed significantly less biomass loss and reproductive inhibition, as well as lower Ag bioaccumulation (15.6 mg/kg) compared with one-step exposure (17.9 mg/kg). The increases in enzyme activities (superoxide enzyme and catalase) and gene expression (metallothionein) also implied higher antioxidant and genetic toxicity in one-step exposed earthworms compared with those from progressively repeated exposure. Furthermore, the transcriptomic analysis identified 582 and 854 differentially expressed genes in the treatments of one-step and repeated exposure respectively compared with the control group. The results of pathway annotation and classification suggested similar enrichments of damage induction but different in toxic stress responses, whereas earthworms from repeated exposure possessed more detoxification-related pathways like translation and multicellular organismal processes. This study innovatively took into account the impacts of processive exposure occurring in the real environment and elucidated distinctions of toxicity and adaptation caused by different exposure patterns, which provided the theoretical basis for real risk identification under the framework and guidance of traditional toxicology, also the implication for the improvement of eco-toxicological risk assessment.

Reproductive damage and compensation of wild earthworm Metaphire californica from contaminated fields with long-term heavy metal exposure.

Reproduction is a significant biological process for organisms responding to environmental stresses, however, little is known about the reproductive strategies of invertebrates under long-term exposure to contaminations. In this study, earthworm Metaphire californica (Kinberg, 1867) from contaminated fields with an increased metal gradient were collected to investigate their reproductive responses. The results showed heavy metals (Cd, Cu, Zn, and Pb) induced histological damage to earthworms' seminal vesicles, including tissue disorders and cavities, and decreases in mature spermatozoa. Sperm morphology analysis indicated deformity rates were up to13.2% (e.g. head swollen or missing) for worms from the most contaminated site, which coincided with DNA damages. Furthermore, the computer-assisted sperm analysis (CASA) system was employed for the evaluation of sperm kinetic traits. Results suggested earthworms exposed to higher contamination showed a lower sperm viability rate but faster sperm velocity after re-exposure with Cd solution (like the curvilinear velocity and straight-line velocity paraments) compared with those from relatively clean sites. The activities of lactate dehydrogenase and sorbitol dehydrogenase showed the highest 32.5% and 12.5% up-regulation respectively with the increased metal gradient. In conclusion, this study elucidated the earthworm reproductive toxicity, underlying reproductive compensation, metal stress-induced damages, and adaptive responses caused by heavy metal exposure, while also providing the possibility of sperm trait analysis (CASA) for related earthworm toxicological studies.