Elevated ozone decreases the multifunctionality of belowground ecosystems

Elevated tropospheric ozone (O₃) affects the allocation of biomass aboveground and belowground and influences terrestrial ecosystem functions. However, how belowground functions respond to elevated O₃ concentrations ([O₃]) remains unclear at the global scale. Here, we conducted a detailed synthesis of belowground functioning responses to elevated [O₃] by performing a meta-analysis of 2395 paired observations from 222 publications. We found that elevated [O₃] significantly reduced the primary productivity of roots by 19.8%, 16.3%, and 26.9% for crops, trees and grasses, respectively. Elevated [O₃] strongly decreased the root/shoot ratio by 11.3% for crops and by 4.9% for trees, which indicated that roots were highly sensitive to O₃. Elevated [O₃] impacted carbon and nitrogen cycling in croplands, as evidenced by decreased dissolved organic carbon, microbial biomass carbon, total soil nitrogen, ammonium nitrogen, microbial biomass nitrogen, and nitrification rates in association with increased nitrate nitrogen and denitrification rates. Elevated [O₃] significantly decreased fungal phospholipid fatty acids in croplands, which suggested that O₃ altered the microbial community and composition. The responses of belowground functions to elevated [O₃] were modified by experimental methods, root environments, and additional global change factors. Therefore, these factors should be considered to avoid the underestimation or overestimation of the impacts of elevated [O₃] on belowground functioning. The significant negative relationships between O₃-treated intensity and the multifunctionality index for croplands, forests, and grasslands implied that elevated [O₃] decreases belowground ecosystem multifunctionality.     

Cradle-to-gate life cycle assessment of cobalt sulfate production derived from a nickel–copper–cobalt mine in China

Purpose

In the booming electric vehicle market, the demand for refined cobalt is showing a blowout growth. China is the largest cobalt-refiner and cobalt-importer in the world. However, the life cycle inventory and potential environmental impact from cobalt refining in China have not been clearly illustrated. This paper builds a comprehensive inventory to support the data needs of downstream users of cobalt sulfate. A “cradle-to-gate” life cycle assessment was conducted to provide theoretical support to stakeholders.

Methods

A life cycle assessment was performed based on ISO 14040 to evaluate the potential environmental impact and recognize the key processes. The system boundary of this study contains four stages of cobalt sulfate production: mining, beneficiation, primary extraction, and refining. Except for the experimental data used in the primary extraction stage, all relevant data are actual operating data. The normalization value was calculated based on the latest released global emission and extraction data.

Results and discussion

Normalization results show that the potential impacts of cobalt refining were mainly concentrated in the fossil depletion and freshwater ecotoxicity categories. The beneficiation stage and the refining stage account for 72% and 26% of the total normalization value, respectively. The beneficiation stage needs to consume a lot of chemicals and energy to increase the cobalt content, due to the low grade of cobalt ore in China. Compared with cobalt concentrate, the use of cobalt-containing waste (e.g., cobalt waste from EV batteries) can ease endpoint impact by up to 73%. With the application of the target electricity structure in 2050, the potential impact of China’s cobalt sulfate production on global warming, fossil depletion, and particulates formation can be reduced by 24%, 22%, and 26%, respectively.

Conclusion

Findings indicate that the chemical inputs and electricity consumption are primary sources of potential environmental impact in China’s cobalt sulfate production. Promoting the development of urban mines can reduce excessive consumption of chemicals and energy in the beneficiation stage. The environmental benefits of transforming the electricity structure and using more renewable energy to reduce dependence on coal-based power in the cobalt refining industry were revealed.

     

Environmental impact assessment of galvanized sheet production: a case study in Shandong Province,China

Purpose

Galvanized sheet is the most widely used coated steel plate globally in the industry of construction, automobile, electronics manufacturing, etc. Large amounts of resources and energy are used in galvanized sheet production, which likewise generates vast amounts of pollutant emissions. In the face of the rapid growth of the production and demand of galvanized sheet in China, it is very important to find out the key factors of the environment impact in the production of galvanized sheet. An evaluation of the environmental impact of galvanized sheet production in China was conducted by using the framework of life cycle assessment to improve resource saving and environmental protection in the galvanized sheet industry, and update the life cycle inventory database of galvanized sheet production.

Methods

The environmental impact assessment was carried out based on the life cycle assessment framework by the use of ReCiPe 2016 method which was applicable on a global scale to evaluate the environmental impact of galvanized sheet production. Methods of uncertainty analysis and sensitivity analysis were adopted to provide credible support.

Results and discussion

The midpoint categories of global warming and fossil resource scarcity, as well as the endpoint categories of human health contributed most to environmental burden, which were mainly caused by carbon dioxide emissions and coal consumption. Environmental impact was dominated by the key process of continuous casting billet production, followed by electrolytic zinc production and electricity generation.

Conclusions

Additional CO₂-reducing measures should be implemented in galvanized sheet production to slow the effect of global warming. Moreover, biomass char reducing agents, rather than coal-based reducing agents, should be utilized in steelmaking to reduce fossil resource consumption. Furthermore, renewable energy, rather than coal-based electricity, should be used in galvanized sheet production to reduce carbon emissions and fossil resource consumption. Increasing the recycling rate of scrap steel and zinc waste can save resources and reduce environmental burden. The results of this study can provide guidance in the reduction of resource consumption and environmental burden of galvanized sheet production to the maximum extent.

     

Overexpressed FATP1, ACSVL4/FATP4 and ACSL1 Increase the Cellular Fatty Acid Uptake of 3T3-L1 Adipocytes but Are Localized on Intracellular Membranes

Long chain acyl-CoA synthetases are essential enzymes of lipid metabolism, and have also been implicated in the cellular uptake of fatty acids. It is controversial if some or all of these enzymes have an additional function as fatty acid transporters at the plasma membrane. The most abundant acyl-CoA synthetases in adipocytes are FATP1, ACSVL4/FATP4 and ACSL1. Previous studies have suggested that they increase fatty acid uptake by direct transport across the plasma membrane. Here, we used a gain-of-function approach and established FATP1, ACSVL4/FATP4 and ACSL1 stably expressing 3T3-L1 adipocytes by retroviral transduction. All overexpressing cell lines showed increased acyl-CoA synthetase activity and fatty acid uptake. FATP1 and ACSVL4/FATP4 localized to the endoplasmic reticulum by confocal microscopy and subcellular fractionation whereas ACSL1 was found on mitochondria. Insulin increased fatty acid uptake but without changing the localization of FATP1 or ACSVL4/FATP4. We conclude that overexpressed acyl-CoA synthetases are able to facilitate fatty acid uptake in 3T3-L1 adipocytes. The intracellular localization of FATP1, ACSVL4/FATP4 and ACSL1 indicates that this is an indirect effect. We suggest that metabolic trapping is the mechanism behind the influence of acyl-CoA synthetases on cellular fatty acid uptake.     

Identification of aluminum-responsive microRNAs in Medicago truncatula by genome-wide high-throughput sequencing

MicroRNAs (miRNAs) play important roles in response of plants to biotic and abiotic stresses. Aluminum (Al) toxicity is a major factor limiting plant growth in acidic soils. However, there has been limited report on the involvement of miRNAs in response of plants to toxic Al³⁺. To identify Al³⁺-responsive miRNAs at whole-genome level, high-throughput sequencing technology was used to sequence libraries constructed from root apices of the model legume plant Medicago truncatula treated with and without Al³⁺. High-throughput sequencing of the control and two Al³⁺-treated libraries led to generation of 17.1, 14.1 and 17.4 M primary reads, respectively. We identified 326 known miRNAs and 21 new miRNAs. Among the miRNAs, expression of 23 miRNAs was responsive to Al³⁺, and the majority of Al³⁺-responsive mRNAs was down-regulated. We further classified the Al³⁺-responsive miRNAs into three groups based on their expression patterns: rapid-responsive, late-responsive and sustained-responsive miRNAs. The majority of Al³⁺-responsive miRNAs belonged to the ‘rapid-responsive’ category, i.e. they were responsive to short-term, but not long-term Al³⁺ treatment. The Al³⁺-responsive miRNAs were also verified by quantitative real-time PCR. The potential targets of the 21 new miRNAs were predicted to be involved in diverse cellular processes in plants, and their potential roles in Al³⁺-induced inhibition of root growth were discussed. These findings provide valuable information for functional characterization of miRNAs in Al³⁺ toxicity and tolerance.     

Amplicon Sequencing of Colorectal Cancer: Variant Calling in Frozen and Formalin-Fixed Samples

Next generation sequencing (NGS) is an emerging technology becoming relevant for genotyping of clinical samples. Here, we assessed the stability of amplicon sequencing from formalin-fixed paraffin-embedded (FFPE) and paired frozen samples from colorectal cancer metastases with different analysis pipelines. 212 amplicon regions in 48 cancer related genes were sequenced with Illumina MiSeq using DNA isolated from resection specimens from 17 patients with colorectal cancer liver metastases. From ten of these patients, paired fresh frozen and routinely processed FFPE tissue was available for comparative study. Sample quality of FFPE tissues was determined by the amount of amplifiable DNA using qPCR, sequencing libraries were evaluated using Bioanalyzer. Three bioinformatic pipelines were compared for analysis of amplicon sequencing data. Selected hot spot mutations were reviewed using Sanger sequencing. In the sequenced samples from 16 patients, 29 non-synonymous coding mutations were identified in eleven genes. Most frequent were mutations in TP53 (10), APC (7), PIK3CA (3) and KRAS (2). A high concordance of FFPE and paired frozen tissue samples was observed in ten matched samples, revealing 21 identical mutation calls and only two mutations differing. Comparison of these results with two other commonly used variant calling tools, however, showed high discrepancies. Hence, amplicon sequencing can potentially be used to identify hot spot mutations in colorectal cancer metastases in frozen and FFPE tissue. However, remarkable differences exist among results of different variant calling tools, which are not only related to DNA sample quality. Our study highlights the need for standardization and benchmarking of variant calling pipelines, which will be required for translational and clinical applications.     

Inhibition of Neuron-Specific CREB Dephosphorylation is Involved in Propofol and Ketamine-Induced Neuroprotection Against Cerebral Ischemic Injuries of Mice

Propofol and ketamine may provide certain degree of neuroprotection, but the underlying mechanism remains unclear to date. The cAMP response element-binding protein (CREB) was proposed that its phosphorylation at Ser133 (P-CREB) constituted a convergence point involved in neuroprotection. The purpose of this study was to determine whether different dosages of propofol and ketamine could provide neuroprotection against permanent middle cerebral artery occlusion (MCAO)-induced ischemic injuries and the involvement of P-CREB. Eighty adult male BALB/c mice that underwent 6 h MCAO were randomly divided into eight groups: Sham-operation; MCAO + saline; MCAO + 25, 50, 100 mg/kg propofol; and MCAO + 25, 50, 100 mg/kg ketamine (intraperitoneal injection 30 min following MCAO). We found that 50, 100 (not 25) mg/kg propofol, and 25 (not 50 and 100) mg/kg ketamine could significantly reduce the infarct volume, edema ratio and neurological deficit (n = 10 per group) as well as inhibit the decrease of P-CREB level in peri-infarct region when compared with that of MCAO + saline group (n = 6 per group). In addition, the results of double-labeled immunofluorescent staining showed that P-CREB co-localized with neuron-specific marker, NeuN, in the peri-infarct region of 50 mg/kg propofol and 25 mg/kg ketamine treated 6 h MCAO mice (n = 4 per group). These results suggested that inhibition of neuron-specific P-CREB dephosphorylation in the peri-infarct region is involved in high dose propofol and low dose ketamine-induced neuroprotection of 6 h MCAO mice.     

Environmental impact assessment of ground source heat pump system for heating and cooling: a case study in China

The International Journal of Life Cycle Assessment - Ground source heat pump (GSHP) utilizes shallow geothermal energy to meet the heating and cooling needs of buildings. It has drawn global...