Cr Treatment Research Articles

Chromium Remediation from Tannery Wastewater in Arequipa, Peru: Local Experiences and Prospects for Sustainable Solutions

The release of tannery wastewater contributes to chromium (Cr) pollution globally. Herein, we conduct a novel consolidation of research from the Arequipa region of southern Peru that integrates university theses written in Spanish alongside peer-reviewed journal articles. The objective is to provide a place-based complement to existing research in English scientific journals focused on effective tools for Cr treatment from tannery wastewater. Our consolidation categorized a total of 75 publications (70 theses and five peer-reviewed) into five distinct strategies for Cr treatment: adsorption (twenty-three studies), phytoremediation (eighteen studies), bioremediation (thirteen studies), electrocoagulation (five studies), and other techniques (fifteen studies). This synthesis highlighted potentially promising approaches that could be sustainably tailored to regional resources and waste products. This includes sorptive materials derived from food waste such as native achiote peels (B. orellana) and avocado seeds (P. americana) either used directly or as a feedstock for biochar. Other technologies include phytoremediation using microalgae and resident vascular plants and microbial bioremediation that capitalizes on indigenous bacteria and fungi. Promise was also discerned in studies that incorporated a combination of abiotic and biotic mechanisms tailored toward the region, such as infiltration using selective and bioactive materials, wetlands, solar distillation, iron-based coagulation and flocculation, and bioreactors. These findings provide a sustainable complement to prior global investigations for effective attenuation strategies by adding novel materials and techniques that could be further explored to assess the viability of implementation at pilot and larger scales. These promising technologies and the ability to tailor sustainable treatments toward local resources highlight the opportunity to prioritize the treatment of tannery wastewater to ensure a cleaner environment by informing policy makers, academics, and industry on technologies that could be adopted for implementation in the region.

Comparison of Functional Electrical Stimulation Cycle vs. Conservative Rehabilitation on Functional Status and Muscle Features in Stroke Patients

Background Functional Electrical Stimulation (FES) Cycle is used in the rehabilitation of stroke. Objective The aim of this study is to investigate the effects of CR and FES cycle therapy on the functional status and muscle features in stroke patients Methods The 1st Group(n = 15) received only CR for 6 weeks, and the 2nd Group(n = 15) received FES cycle 3 days a week for 4 weeks in addition to the CR treatment. Brunnstrom recovery staging(BRS), Fugl-Meyer lower extremity evaluation(FME); Berg Balance Scale(BBS), Functional Ambulation Classification(FAC), Barthel Index(BI), Fatigue Severity Scale(FSS), 6 min walk test(6mWT), knee extensor and knee flexor muscle strengths(KEMS, KFMS) in both groups were assessed before and after treatment(6th week). Pennate angle(PA) and rectus femoris muscle thickness(RFT) were measured. Results Significant improvement was detected in BBS, FAS, BI, FME, 6mWT, KEMS, RFT scores after intra-group treatment compared to before treatment in both groups. Only the 2nd Group showed a significant difference in KFMS, FSS, BRS lower extremity, PA values after treatment compared to before. No significant superiority of the groups over each other was detected. Conclusions CR and FES Cycle contribute to the improvement of the functional status of the patients, but their superiority over each other was not observed.

Highland barley ELNs and physiological responses to different concentrations of Cr (VI) stress.

This study is the first to use highland barley (HB) to study the toxic effects of Cr (VI) on seedlings and the response mechanism of HELNs to Cr (VI) stress. The outcomes indicated that the germination rate of HB seeds, plant height, root length, water content, and levels of proline (PRO) and soluble sugar in both leaves and roots were all impacted by varying concentrations of Cr (VI) treatments. Differential changes in the activities of antioxidant enzymes (SOD, POD, CAT) were observed in leaves and roots of HB. We also extracted HB-derived ELNs (HELNs) and characterized and sequenced HELNs. The average particle size of CK-HELNs was 79.0 nm, and the concentration of HELNs was 4.56 E+10 (particles/mL). As the concentration of Cr (VI) increased, the particle size of HELNs in HB seedlings also increased, while the concentration decreased. A total of 29 miRNA species were identified in CK-HELNs, Cr10-HELNs, and Cr40-HELNs. Out of these, 25 were newly predicted miRNAs, and the remaining four were known miRNAs. A total of 2 known miRNAs and 11 novel miRNAs were upregulated under different concentrations of Cr (VI) stress. 1 known and 5 novel miRNAs were downregulated under different concentrations of Cr (VI) stress. Enrichment of the GO and KEGG pathways revealed that the differential gene functions were mainly focused on binding and catalytic activities. This study reveals for the first time the changes of HELNs under different concentrations of Cr (VI) stress and the toxic effects of Cr (VI) on HB seedlings. This study provides a new perspective to explore the function and utilisation of ELNs.

Efficient Solar-Powered Bioremediation of Hexavalent Chromium in Contaminated Waters by Chlorella sp. MQ-1

Microalgae are known for their efficient removal of hexavalent chromium (Cr(VI)) through biosorption and bioaccumulation, yet the subsequent release of Cr(VI) upon cell death remains a challenge. The reduction of Cr(VI) to the less toxic trivalent chromium [Cr(III)] is another critical remediation strategy that mitigates the risk of Cr(VI) re-release, but research on microalgal reduction of Cr(VI) is scarce. In this study, a microalgal strain designated as MQ-1 was isolated from chromium-contaminated mine effluent, demonstrating the capability to tolerate and remove Cr(VI). Phylogenetic analysis revealed that MQ-1 is closely related to the genus Chlorella; hence, it is classified as Chlorella sp. MQ-1. This strain exhibited robust growth at Cr(VI) concentrations below 2 mg/L, achieving a removal rate higher than 82% for initial Cr(VI) concentrations between 0.5 and 1 mg/L after a 5-day incubation period. Mechanistic studies revealed that MQ-1 promoted the removal of Cr(VI) mainly through intracellular bioreduction and bioaccumulation processes, in which more than 60% of Cr(VI) was reduced to the less toxic Cr(III) and stocked in the cells. A two-stage cultivation strategy, involving initial biomass accumulation followed by Cr(VI) treatment, significantly enhanced the removal efficiency, which was further accelerated under illuminated conditions. Notably, MQ-1 cultures with initial OD680 values of 4 and 6 accomplished 84.28% and 91.31% Cr(VI) removal from 2 mg/L solutions, respectively, within 30 hours under light exposure. These findings highlight the potential of MQ-1 to utilize renewable solar energy to reduce Cr(VI) and to mitigate the risk of its re-release into the environment. This characteristic positions MQ-1 as a potentially sustainable and cost-effective solution for Cr(VI) remediation and suggests its significant potential for large-scale implementation in bioremediation strategies aimed at Cr(VI)-contaminated waters.

Soil Microorganism Interactions under Biological Fumigations Compared with Chemical Fumigation.

Biological fumigation, a potential alternative to chemical fumigation, shows a wide range of prospective applications. In this study, we carried out biological fumigation experiments to evaluate its effect on alleviating consecutive cropping problems (CRPs) when compared with chemical fumigation. We designed five treatments, namely, CR (no treatment), LN (chemical fumigation with lime nitrogen), Ta (fumigation with marigold), Ra (fumigation with radish), and Br (fumigation with mustard), for soils for replanting eggplant and measured the crop's growth status, soil bacterial and fungal communities, and soil physicochemical properties. The results showed that the Br and Ra treatments formed similar microbial communities, while the Ta treatment formed unique microbial communities. The genera Olpidiomycota and Rozellomycota could be used as indicator species for the transformation process of soil microbial communities after the Br and Ta treatments, respectively. When compared with the CR and LN treatments, the soil's physicochemical properties were optimized under the Br treatment, and the soil organic matter content increased by 64.26% and 79.22%, respectively. Moreover, under the Br treatment, the soil's biological properties enhanced the bacterial and fungal alpha diversity, and the saprotrophic fungi increased with the depletion of pathotrophic fungi, while some specific probiotic microorganisms (such as Olpidiomycota, Microascales, Bacillus, etc.) were significantly enriched. In contrast, under the Ta treatment, soil nutrient levels decreased and the soil's biological indices deteriorated, whereas the bacterial diversity decreased and the pathogenic fungi increased. Among these three biological fumigation methods, the Br pre-treatment was the best way to alleviate the crop's CRPs and may be a good substitute for chemical fumigation in some situations. However, the Ta treatment also had some risks, such as the loss of land quality and reduced productivity.

Bioremediation of chromium-induced toxic effects in Nile tilapia (Oreochromis niloticus) using probiotics

Chromium (Cr) is one of the major heavy metal pollutants and its toxicity causes an adverse impact on body physiology of aquatic organisms including fish. Probiotics may be able to degrade toxic effects of Cr, thereby mitigating its adverse effects on the fish body. In this study, Nile tilapia (35.29 ± 1.21) was subjected to: control (without Cr or probiotics), hexavalent Cr (potassium dichromate) treatment (10 mg/L), probiotics treatment (1 ml/L), and combination of Cr and probiotics treatment (10 mg Cr/L and 1 ml probiotics/L) for a period of six weeks (42 days). The results showed that growth performance (weight gain; WG, specific growth rate; SGR) and feed utility (feed conversion ratio; FCR) were inhibited significantly in Cr-treated group compared to the control, while those parameters were found to be regained in probiotics-treated group as to control. In case of hemato-biochemical parameters (hemoglobin and glucose), Cr-exposed fish showed lower hemoglobin and higher glucose levels; however, the use of probiotics showed their level as to control. The number of cellular (teardrop, twin, spindle, and echinocyte shaped) and nuclear (notched nuclei, nuclear buds, nuclear bridges, and karyopyknosis) abnormalities in erythrocytes were higher in the Cr-exposed group. However, probiotic addition leading to a notable decrease these abnormalities. Similarly, higher deformities were observed in the gills and intestine of the fish exposed to Cr, while the administration of probiotics reduced these abnormalities. Overall, probiotics appear to have the potential to mitigate the negative physiological effects of Cr on Nile tilapia.

Treatment strategies with electrochemotherapy for limb in-transit melanoma: Real-world outcomes from a European, retrospective, cohort study

BackgroundThis study analysed treatment strategies with electrochemotherapy (ECT) in melanoma with limb in-transit metastases (ITM). MethodsWe audited AJCC v.8 stage IIIB-IIID patients treated across 22 centres (2006–2020) within the International Network for Sharing Practices of ECT (InspECT). Results452 patients were included, 58 % pre-treated (93 % had lower limb ITM, 44 % had ≤10 metastases [median size 1.5 cm]. Treatment strategies included first-line ECT (n = 145, 32 %), ECT with concurrent locoregional/systemic treatment (n = 163, 36 %), and salvage ECT (n = 144, 32 %). The objective response rate was 63 % (complete response [CR], 24 %), increasing to 74 % (CR, 39 %) following retreatment (median two ECT, range 1–8). CR rate in treatment-naïve and pre-treated patients was 50 % vs 32 % (p < 0.001). Bleomycin de-escalation was associated with lower CR (p = 0.004). Small tumour number and size, hexagonal electrode, retreatment, and post-ECT skin ulceration predicted response in multivariable analysis. At a median follow-up of 61 months, local and locoregional recurrence occurred in 55 % and 81 % of patients. Median local progression-free, new lesions-free, and regional recurrence-free survival were 32.9, 6.9, and 7.7 months. Grade-3 toxicity was 15 %. Concurrent treatment and CR correlated with improved regional control and survival. Concomitant checkpoint inhibition did not impact toxicity or survival outcomes. The median overall survival was 5.7 years. ConclusionsAmong patients with low-burden limb-only ITM, standard-dose bleomycin ECT results in durable local response. Treatment naivety, low tumour volume, hexagonal electrode application, retreatment, and post-ECT ulceration predict response. CR and concurrent treatment correlate with improved regional control and survival outcomes. Combination with checkpoint inhibitors is safe but lacks conclusive support.

Salvia officinalis L. resilience under chromium stress: An integrated study of growth, physiology, biochemical changes and rosmarinic acid production

Medicinal plants are increasingly challenged by rising chromium (Cr) levels in agricultural soil and water bodies due to industrialization and human activities. This research examines the impact of various chromium concentrations on Salvia officinalis L., a medicinal herb, over 3 specific time periods: 30, 60 and 90 days. As the duration of Cr exposure increases, various growth parameters showed an upward trend at the lowest concentrations, with the most robust growth observed in the 20 ppm Cr treatment group after 90 days. However, higher chromium concentrations resulted in reduced plant growth compared to untreated plants. Chromium primarily accumulates in the roots, stems and leaves, with the highest accumulation observed at 100 ppm. However, chlorophyll content declined with prolonged Cr exposure, particularly at higher concentrations. Carbohydrate levels initially increased at lower Cr concentrations but decreased with greater exposure, while protein content consistently decreased with elevated Cr levels. Proline levels exhibited mixed responses, rising at lower concentrations and declining at higher ones. Malondialdehyde (MDA) content increased with higher Cr levels and extended exposure. The enzymatic antioxidant system showed an initial increase followed by a decline with prolonged exposure. Rosmarinic acid content increased with chromium (Cr) exposure upto 60 ppm but subsequently decreased beyond that threshold. In the first 30 days, plants treated with Cr demonstrated a 17 % increase in rosmarinic acid production compared to the control (48.9 mg/g DW). However, with continued Cr exposure, there was a decline in rosmarinic acid production ranging from 10 % to 20 % compared to the control level (67.02 mg/g DW) at 90 days post-treatment. These findings underscore the complex and contrasting responses of Salvia officinalis to Cr toxicity, highlighting the necessity for extended study into the core mechanisms governing these responses and the development of strategies to alleviate heavy metal stress in plants.

Urolithin A attenuates hexavalent chromium-induced small intestinal injury by modulating PP2A/Hippo/YAP1 pathway

Hexavalent chromium (Cr(VI)) exposure has been linked with gastrointestinal toxicity, whereas the molecular pathways and key targets remain elusive. Computational toxicology analysis predicted the correlation between protein phosphatase 2A (PP2A) and genes regarding Cr(VI)-induced intestinal injury. Here, we generated a mouse model with intestinal epithelium-specific knock out of Ppp2r1a (encoding PP2A Aα subunit) to investigate the mechanisms underlying Cr(VI)-induced small intestinal toxicity. Heterozygous (HE) mice and matched WT littermates were administrated with Cr(VI) at 0, 5, 20, and 80mg/l for 28 successive days. Cr(VI) treatment led to crypt hyperplasia, epithelial cell apoptosis, and intestinal barrier dysfunction, accompanied by the decline of goblet cell counts and Occludin expression in WT mice. Notably, these effects were aggravated in HE mice, indicating that PP2A Aα deficiency conferred mice with susceptibility to Cr(VI)-induced intestinal injury. The combination of data analysis and biological experiments revealed Cr(VI) exposure could decrease YAP1 phosphorylation at Ser127 but increase protein expression and activity, together with elevated transcriptional coactivator with PDZ-binding motif protein driving epithelial crypt cells proliferation following damage, suggesting the involvement of Hippo/YAP1 signaling pathway in Cr(VI)-induced intestinal toxicity. Nevertheless, the enhanced phosphorylation of YAP1 in HE mice resulted in proliferation/repair defects in intestinal epithelium, thereby exacerbating Cr(VI)-induced gut barrier dysfunction. Notably, by molecular docking and further studies, we identified urolithin A, a microbial metabolite, attenuated Cr(VI)-induced disruption of intestinal barrier function, partly by modulating YAP1 expression and activity. Our findings reveal the novel molecular pathways participated in Cr(VI)-caused small intestinal injury and urolithin A could potentially protect against environmental hazards-induced intestinal diseases.

Precisely constructed core-shell organic/inorganic heterojunction for heightened photoreduction of Cr(VI): Synergy of reinforced interface interaction and high-speed carrier transfer

Photocatalysis technology has been widely studied for treating Cr(VI) pollution in water and constructing heterogeneous structures presents a compelling approach to enhance the efficiency of Cr(VI) treatment. Pitifully, solely utilizing heterostructure, especially random composites of heterogeneous photocatalysts, often falls short of effectively enhancing the separation efficiency of photogenerated carriers. Furthermore, most photocatalysts interact weakly with the Cr(VI) anions, greatly reducing the utilization efficiency of photogenerated carriers. Herein, pyridine-based conjugated imprinted polymer (CIP) photocatalyst was precisely coated on urchin-like TiO2 using an in-situ condensation approach, forming a compact core–shell structure of organic/inorganic heterojunction. On the one hand, the compact heterojunction structure of the core–shell effectively improved the separation efficiency of photogenerated carriers. On the other hand, CIP enhanced the adsorption between the photocatalyst and Cr(VI), effectively improving the utilization efficiency of photogenerated carriers. Due to the collaborative effects of selective adsorption and core–shell heterojunction photocatalysis, the photocatalyst demonstrated remarkable performance in eliminating Cr(VI). For high concentration Cr(VI) pollution of 100 ppm, complete elimination could be achieved within 90 min. This research presented an innovative and efficient approach for the precise synthesis of photocatalysts.

Genomic and proteomic analyses reveal the reduction mechanism of hexavalent chromium by the culturing supernatant of strain Pediococcus acidilactici 13-7

This study used lactic acid bacteria with high antioxidative properties to screen for strains capable of reducing hexavalent chromium [Cr (VI)] in their culturing supernatants. The strain Pediococcus acidilactici 13–7 exhibited potent Cr (VI)-reducing capability and remarkable resistance to Cr (VI) even at concentration as high as 24 mM. Comparative genomics analysis revealed a unique gene, ChrR, associated with Cr (VI) reduction in this strain, distinguishing it from four reference strains of P. acidilactici. The proteomic investigation identified proteins linked to the ChrR gene, such as nqo1, frdA, and gshR, indicating significant enrichment in redox-related functions and oxidative phosphorylation pathways. These findings suggest that P. acidilactici 13–7 possesses superior electron transfer capacity compared to other strains, making it more adaptable under highly oxidative conditions by modulating the external environment to mitigate oxidative stress. Collectively, the results demonstrated the potential application of this lactic acid bacterial strain for bioremediation of heavy metals by its ability to reduce Cr (VI), and shed light on the molecular mechanisms underlying Cr (VI) reduction of the strain P. acidilactici 13–7.

Exogenous proline regulates pectin demethylation by rescuing pectin methylesterase functioning of cell wall from Cr(VI) toxicity in rice plants

BackgroundPlants are equipped with several sophisticated mechanisms to deal with heavy metals (HMs) toxicity. Cell walls, which are rich in pectin, are important in the sequestration and compartmentalization of HMs. Pectin demethylation is carried out by pectin methylesterase (PME), which is a crucial activity in cell walls for the adsorption of HMs. This study focused on the factors that contribute to chromium (Cr) adsorption in rice plants exposed to Cr(VI) treatments without proline (Pro) “Cr(VI)” and with Pro “Pro + Cr(VI)” application.ResultsThe results exhibited that when rice plants were treated with Cr(VI), their PME activity decreased, because Cr(VI) was bound to certain isoforms of PME and prevented the demethylation of pectin. The application of Pro increased PME activity by promoting the transcription of several PME-related genes. These genes were recognized on the basis of their similarity with PME genes in Arabidopsis. Gene expression variation factors (GEVFs) between the “Cr(VI)” and “Pro + Cr(VI)” treatments revealed that OsPME7 and OsPME9 have the highest positive GEVF values than other OsPME genes of rice. In addition, Pro application increased pectin content significantly in rice plants exposed to Cr(VI) stress. Proline application also leads to an increased concentration of Cr in rice roots compared with “Cr(VI)” treatments alone.ConclusionsThese findings suggest that Pro increased Cr(VI) adsorption in cell walls of rice plants by enhancing the PME activity and pectin content when exposed to “Cr(VI)” treatments, mainly regulated by OsPME7 and OsPME9.Graphical

Magnetic Ion-Imprinted Materials for Selective Adsorption of Cr(VI): Adsorption Behavior and Mechanism Study.

With the increase of hexavalent Cr(VI) wastewater discharged from industrial production, it seriously pollutes water bodies and poses a risk to human health. Adsorption is used as an effective means to treat Cr(VI), but its effectiveness is affected by pH, and the adsorption performance decreases when acidity is strong. Furthermore, research on the mechanism of Cr(VI) adsorption using DFT calculations needs to be developed. This study focuses on the development of magnetically responsive core-shell nano-ion imprinted materials (Fe3O4@GO@IIP) through magnetic separation and surface imprinting techniques. Characterization techniques including FT-IR, XRD, and EDS confirmed the core-shell nanostructure of Fe3O4@GO@IIP. Batch adsorption experiments and model simulations demonstrated the exceptional adsorption capacity of Fe3O4@GO@IIP for Cr(VI) in strongly acidic solutions (pH = 1), reaching a maximum of 89.18 mg/g. The adsorption mechanism was elucidated through XPS and DFT calculations, revealing that Fe3O4@GO@IIP operates through electrostatic interactions and chemical adsorption, with charge transfer dynamics quantified during the process. This research provides new insights for addressing Cr(VI) treatment in highly acidic environments.

Crocin, the compound of the dried stigma of Crocus sativus L (saffron), restores doxorubicin-induced disturbances in kidney functioning, oxidative stress, inflammation, renal tissue morphology and TGF-β signalling pathways

Doxorubicin (Dox), an anthracycline antibiotic, is a chemotherapeutic drug for several cancer treatments. However, its clinical usage has been restricted because of severe side effects, including nephrotoxicity. This study aimed to demonstrate the possible nephroprotective effects of crocin (Cr) against Dox-induced oxidative stress, renal inflammation, renal morphology and transforming growth factor-β (TGF-β) signalling pathways in Dox-exposed rats. Hence, the rats were injected for 15 d consecutively with saline, six different injections of Dox until the cumulative dose reached 12 mg/kg., daily Cr (40 mg/kg), and Dox + Cr combination. Cr increased the activities of superoxide dismutase (SOD) and catalase (CAT), GSH content and suppressed inflammation and oxidative stress in Dox-exposed rats. Our results were confirmed by immunohistochemical findings that Cr treatment ameliorates the expressions of IL1β and TGF-β in Dox-induced nephrotoxicity. Conclusionally, Cr exhibits adequate nephroprotective effects against Dox-induced nephrotoxicity on rat kidney architecture and tissue function by stabilising cellular redox homeostasis, reducing renal fibrosis and suppressing inflammation.

A novel quaternary ammonium structure of carbon dots modified TiO2 for fast reduction of Cr(VI) over a wide pH range under sunlight

Cr(VI) pollution in water caused by industrialization poses a serious threat to human health and ecosystems, necessitating a rapid reduction of Cr(VI) treatment method. Therefore, We have established a photocatalytic method for the rapid reduction of Cr(VI) by modifying TiO2 with carbon dots (CPC-CDs) that possess a quaternary ammonium structure in the first time. The CPC-CDs widens the band gap of TiO2 and increases the electrostatic interactions between CPC-CDs/TiO2 and Cr(VI), thus improving the reduction efficiency. CPC-CDs/TiO2 (0.1 g, 2 % CPC-CDs) exhibited excellent reduction performance and fully reduced Cr(VI) (50 mg/L) under neutral conditions within 150 min using a xenon lamp to simulate sunlight. Moreover, CPC-CDs/TiO2 achieved more than 95 % reduction efficiency over a wide pH range (pH = 3, 5, 7, and 9) and showed excellent reduction of Cr(VI) at various concentrations (10, 20, 30, 40 and 50 mg/L). CPC-CDs/TiO2 maintained high Cr(VI) reduction efficiency (93.57 %) after five cycles. Tests under real sunlight revealed that CPC-CDs/TiO2 thoroughly reduced Cr(VI) (10 mg/L) within 30 min, and exhibited excellent structural stability under conditions with interfering ions. Furthermore, CPC-CDs/TiO2 exhibited prominent antibacterial activity against Escherichia coli. In addition, free-radical trapping experiments verified that the superoxide radicals (•O2-) was the main active species. This study aims to overcome the limitations of photocatalytic reduction under conditions of high concentration Cr(VI), neutral and alkaline environments, and natural sunlight, thereby providing technical support for the rapid reduction of Cr(VI).

Transcriptomic analysis reveals particulate hexavalent chromium regulates key inflammatory pathways in human lung fibroblasts as a possible mechanism of carcinogenesis

Hexavalent chromium [Cr(VI)] is considered a major environmental health concern and lung carcinogen. However, the exact mechanism by which Cr(VI) causes lung cancer in humans remains unclear. Since several reports have demonstrated a role for inflammation in Cr(VI) toxicity, the present study aimed to apply transcriptomics to examine the global mRNA expression in human lung fibroblasts after acute (24 h) or prolonged (72 and 120 h) exposure to 0.1, 0.2 and 0.3 μg/cm2 zinc chromate, with a particular emphasis on inflammatory pathways. The results showed Cr(VI) affected the expression of multiple genes and these effects varied according to Cr(VI) concentration and exposure time. Bioinformatic analysis of RNA-Seq data based on the Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and MetaCore databases revealed multiple inflammatory pathways were affected by Cr(VI) treatment. qRT-PCR data corroborated RNA-Seq findings. This study showed for the first time that Cr(VI) regulates key inflammatory pathways in human lung fibroblasts, providing novel insights into the mechanisms by which Cr(VI) causes lung cancer.

Effects of the SEMA4B gene on hexavalent chromium [Cr(VI)]-induced malignant transformation of human bronchial epithelial cells.

Our previous study identified the potential of SEMA4B methylation level as a biomarker for hexavalent chromium [Cr(VI)] exposure. This study aimed to investigate the role of the SEMA4B gene in Cr(VI)-mediated malignant transformation of human bronchial epithelial (BEAS-2B) cells. In our population survey of workers, the geometric mean [95% confidence intervals (CIs)] of Cr in blood was 3.80 (0.42, 26.56) μg/L. Following treatment with various doses of Cr(VI), it was found that 0.5μM had negligible effects on the cell viability of BEAS-2B cells. The expression of SEMA4B was observed to decrease in BEAS-2B cells after 7days of treatment with 0.5μM Cr(VI), and this downregulation continued with increasing passages of Cr(VI) treatment. Chronic exposure to 0.5μM Cr(VI) enhanced the anchorage-independent growth ability of BEAS-2B cells. Furthermore, the use of a methylation inhibitor suppressed the Cr(VI)-mediated anchorage-independent growth in BEAS-2B cells. Considering that Cr levels exceeding 0.5μM can be found in human blood due to occupational exposure, the results suggested a potential carcinogenic risk associated with occupational Cr(VI) exposure through the promotion of malignant transformation. The in vitro study further demonstrated that Cr(VI) exposure might inhibit the expression of the SEMA4B gene to promote the malignant transformation of BEAS-2B cells.

Circ_0008657 regulates lung DNA damage induced by hexavalent chromium through the miR-203a-3p/ATM axis

Hexavalent chromium [Cr (VI)] is an important environmental pollutant and may cause lung injury when inhaled into the human body. Cr (VI) is genotoxic and can cause DNA damage, although the underlying epigenetic mechanisms remain unclear. To simulate the real-life workplace exposure to Cr (VI), we used a novel exposure dose calculation method. We evaluated the effect of Cr (VI) on DNA damage in human bronchial epithelial cells (16HBE and BEAS-2B) by calculating the equivalent real-time exposure dose of Cr (VI) (0 to 10 μM) in an environmental population. Comet experiments and olive tail moment measurements revealed increased DNA damage in cells exposed to Cr (VI). Cr (VI) treatment increased nuclear γ-H2AX foci and γ-H2AX protein expression, and caused DNA damage in the lung tissues of mice. An effective Cr (VI) dose (6 μM) was determined and used for cell treatment. Cr (VI) exposure upregulated circ_0008657, and knockdown of circ_0008657 decreased Cr (VI)-induced DNA damage, whereas circ_0008657 overexpression had the opposite effect. Mechanistically, we found that circ_0008657 binds to microRNA (miR)-203a-3p and subsequently regulates ATM serine/threonine kinase (ATM), a key protein involved in homologous recombination repair downstream of miR-203a-3p, thereby regulating DNA damage induced by Cr (VI). The present findings suggest that circ_0008657 competitively binds to miR-203a-3p to activate the ATM pathway and regulate the DNA damage response after environmental chemical exposure in vivo and in vitro.

Enhancing soil water, carbon, and nitrogen by partially substituting chemical fertilizer with organic fertilizer integrated with a rainwater collection system in rainfed orchards

Rainfed apple orchards, particularly in loess hilly regions of China, face significant challenges due to water scarcity and declining soil fertility, necessitating their restoration for sustainable apple production. This study investigated the impact of partially substituting chemical fertilizers with organic fertilizers integrated with a rainwater collection system on restoring soil water storage (SWS), soil organic carbon (SOC) stocks, and total nitrogen (TN) stocks and their relationship with apple production. Three orchard management practices were evaluated: (1) OSCR: partially substituting chemical fertilizer with organic fertilizer (60% N from organic fertilizer) integrated with a rainwater collection system; (2) CR: chemical fertilizer integrated with a rainwater collection system; and (3) CK: chemical fertilizer alone without a rainwater collection system. Averaged across five years, the OSCR treatment (457.83 mm) substantially enhanced SWS from 0 to 280 cm profile by 19.12% compared to the CK (384.34 mm). OSCR system outperformed CR treatment in terms of the 0–280 cm SWS compensation index (SWSCI). The OCSR and CR treatments had higher SWSCI values in 2016 (dry year) than the other years, indicating more effective SWS restoration in dry years. Average across five years, OSCR treatment had 55.26% and higher SOC stock (214.1 Mg ha–1) and 45.91% higher TN stock (5.72 Mg ha−1) from 0 to 280 cm than the CK; and the OSCR treatment positively restored SOC and TN stocks, while the CR treatment decreased SOC stock and restored TN stock from 0 to 200 cm profile. Compared to 2016, OSCR, CR and CK treatments increased SOC stock by 36.84%, −5.78% and −6.98%, and TN stock by 36.31%, 37.88 and −3.36% in 2020, respectively. Average across five years, the OSCR treatment had the highest mean apple yield (24.61 Mg ha−1) and crop water production (CWP, 48.64 kg ha−1 mm−1), 64.62% and 66.69% higher than the CK treatment across five years; no significant differences in fruit size or shape index occurred between treatments. The difference in apple yield is unfavorably connected with SWSCI and favorably connected with SOC and TN stock restoration. Overall, the OSCR system successfully restored SWS, SOC, and TN stocks, increasing apple yield and CWP, making it a promising management strategy for rainfed apple orchards.

Anti-Tumor Effect and Mechanism Study of Caloric Restriction, Achieved by Time-Restricted Feeding, in Mice.

To evaluate the therapeutic effects and explore the mechanisms behind caloric restriction achieved through time-restricted feeding (CR) in inhibiting mouse tumors, providing a theoretical basis and data support for future CR diet-assisted anticancer treatment protocols. C57BL/6 and BALB/c mice were divided into four cell line groups. Each group was further split into normal diet (ND) and a CR diet groups. The ND groups had free access to water and a normal diet, while the CR diet groups had access to water but were only fed from 9 a.m. to 11 a.m., fasting for the remaining 22h. Food intake was recorded daily starting on day 1 of the experiment. Tumor models were established and assessed every 2days. Blood biochemical indicators, serum pyruvic acid levels, and cytokine expression were measured. The CR diet inhibited tumor growth in mice. Colorimetric assays and ELISAs showed a reduction in pyruvic acid levels and in key upstream and downstream rate-limiting enzymes in the sera of CR mice. Routine blood and blood biochemistry tests suggested minor effects of the CR diet on these parameters. Western blotting revealed that the CR diet suppressed mTOR and AKT protein expression in tumor tissues. ELISA showed that various mTOR-related signaling pathways were downregulated. Immunohistochemistry staining indicated reduced expression of P53, P-AKT, EGFR, and IGF-1 in tumor tissues. TUNEL staining confirmed that the CR diet promoted tumor apoptosis. The CR diet inhibited tumor growth by suppressing mTOR and its related upstream and downstream gene signaling pathways, reducing tumor glycolysis, and accelerating tumor cell apoptosis.