Modeling evolution of cell morphology under stretching.

The mechanical stimulation of cells from the surrounding environment is an important life activity. However, there has been a lack of dynamically quantitative analysis of cell morphology under mechanical stimulations. A theoretical model for the evolution of cell morphology under stretching is proposed by analyzing the transformation between cell deformation energy and adhesion energy. The images of the evolution show that detachment of the adhesion membrane or re-adhesion of the cell, causes a decrease or increase of the adhesion area, respectively. In addition to the stretching amplitude and velocity, we found that the duration of the stretching stage and the no stretching stage can affect the cell morphology during cyclic stretching. The theoretical model explains some counter-intuitive experimental results and provides many quantitative insights into understanding the physical mechanisms of cell adhesion under stretching. This study can provide a useful guide to control cell adhesion under mechanical stimulations.

Preparation of multi-modified/carbonized/gelatinized starch and its de-risking effect on Cd(II) and hymexazol in wastewater.

In this study, starch (S) was gelatinized and carbonized to prepare carbonized/gelatinized S (CGS) as the research material. Then, peat extract (Pe) and surfactants with different ratios were single- and multi-modified on CGS, respectively, to prepare Pe-modified CGS (Pe-CGS) and multi-modified CGS, respectively. The microscopic morphology of multi-modified CGS was studied using various testing methods. The de-risking effect on Cd(II) and hymexazol in wastewater was investigated, and the effects of temperature, pH, and ionic strength were compared. The spheroidal structure of S was destroyed after carbonization, and Pe and surfactants were modified on the surface and changed the surface properties of CGS. The adsorption processes of Cd(II) and hymexazol were suitable to be described by the Langmuir and Freundlich models, respectively. The maximum adsorption capacities (qm) of Cd(II) and adsorption capacity parameter (k) of hymexazol on different modified CGSs presented the peak value at BS/Pe-CGS. With the increase in the modification ratio of Pe, BS, and SDS, qm and k increased, which showed a high value at 100 % modification. Increases in temperature and pH were beneficial to Cd(II) adsorption but were not conducive to hymexazol adsorption. The adsorption amount decreased for Cd(II) and increased first and then reduced for hymexazol with the rise in ionic strength. The adsorption process exhibited spontaneity, endothermic behavior for Cd(II), exothermic behavior for hymexazol, and an entropy-increasing reaction. The adsorption amount of Cd(II) and hymexazol by multi-modified CGS maintained approximately 81 % of the original sample after three rounds of regeneration.

Tanning wastewater restructured nitrogen-transforming bacteria communities and promoted N2O emissions in receiving river riparian sediments.

Physicochemical and toxicological characterization of leather tanning wastewater has been widely documented. However, few reports have examined the response of denitrification N2 and N2O emissions in riparian sediments of tannery wastewater-receiving rivers. In this study, 15N-nitrate labeling was used to reveal the effects of tanning wastewater on denitrification N2 and N2O emission in a wastewater-receiving river (the old Mang River, OMR). OMR riparian sediments were highly polluted with total organic carbon (93.39 mg/kg), total nitrogen (5.00 g/kg) and heavy metals; specifically, Cr, Zn, Cd, and Pb were found at concentrations 47.3, 5.8, 1.6, 4.3, and 2.8 times that in a nearby parallel river without tanning wastewater input (the new Mang River, NMR), respectively. The denitrification N2 emission rates (0.0015 nmol N · g-1 h-1) of OMR riparian sediments were significantly reduced by 2.5 times compared with those from the NMR (p < 0.05), but the N2O emission rates (0.31 nmol N · g-1 h-1) were significantly increased (4.1 times, p < 0.05). Although the dominant nitrogen-transforming bacteria phylum was Proteobacteria in the riparian sediments of both rivers, 11 nitrogen-transforming bacteria genera in the OMR were found to be significantly enriched; five of these were related to pollutant degradation based on linear discriminant analysis (LDA >3). The average activity of the electron transport system in the OMR was 6.3 times lower than that of the NMR (p < 0.05). Among pollution factors, heavy metal complex pollution was the dominant factor driving variations in N2O emissions, microbial community structure, and electron transport system activity. These results provide a new understanding and reference for the treatment of tanning wastewater-receiving rivers.

4.4 kW Nd:YAG slab amplifier with a high repetition frequency and high beam quality.

Using the self-developed fused indium wetting technology and planar waveguide, the uniform heat dissipation of the slab crystal and uniform pumping of the pump light were achieved, respectively. Based on the master oscillator power amplification (MOPA) scheme, the power was then amplified when the seed light source passed through the Nd:YAG slab crystal three times. Additionally, the image transfer system that we added to the amplified optical path achieved high beam quality. Finally, we obtained a rectangular pulsed laser with an output average power of 4461 W, a repetition frequency of 20 kHz, a pulse width of 62 ns, an optical-to-optical conversion efficiency of 26.8%, and a beam quality of ß x=7.0 and ß y=7.7.

Portable Triboelectric Electrostatic Tweezer for External Manipulation of Droplets within a Closed Femtosecond Laser-Treated Superhydrophobic System.

Controllable droplet manipulation has diverse applications; however, limited methods exist for externally manipulating droplets in confined spaces. Herein, we propose a portable triboelectric electrostatic tweezer (TET) by integrating electrostatic forces with a superhydrophobic surface that can even manipulate droplets in an enclosed space. Electrostatic induction causes the droplet to be subjected to an electrostatic force in an electrostatic field so that the droplet can be moved freely with the TET on a superhydrophobic platform. Characterized by its high precision, flexibility, and robust binding strength, TET can manipulate droplets under various conditions and achieve a wide range of representative fluid applications such as droplet microreactors, precise self-cleaning, cargo transportation, the targeted delivery of chemicals, liquid sorting, soft droplet robotics, and cell labeling. Specifically, TET demonstrated the ability to manipulate internal droplets from the outside of a closed system, such as performing cell labeling experiments within a sealed Petri dish without opening the culture system.

Function of FT in Flowering Induction in Two Camellia Species.

FLOWERING LOCUS T (FT), belonging to the FT/TFL1 gene family, is an important gene regulating the flowering transition and inflorescence architecture during plant development. Given its importance to plant adaptation and crop improvement, FT has been extensively studied in related plant research; however, the specific role and underlying molecular mechanisms of FT in the continuous flowering of perennial plants remains elusive. Here, we isolated and characterized homologous FT genes from two Camellia species with different flowering-period phenotypes: CaFT was isolated from Camellia azalea, a precious species blooming in summer and flowering throughout the year, and CjFT was isolated from C. japonica, which blooms in winter and spring. The major difference in the genes between the two species was an additional five-amino acid repeat sequence in C. japonica. FT showed high expression levels in the leaves in both species from January to August, especially in April for C. japonica and in May for C. azalea. CaFT was expressed throughout the year in C. azalea, whereas CjFT was not expressed from September to December in C. japonica. The expression levels of FT in the floral buds were generally higher than those in the leaves. Overexpression of CaFT and CjFT in Arabidopsis indicated that both genes can activate downstream genes to promote flowering. Transgenic callus tissue was obtained by introducing the two genes into C. azalea through Agrobacterium-mediated transformation. Transcriptome and quantitative real-time polymerase chain reaction analyses indicated that both florigen FT genes promoted the expression of downstream genes such as AP1, FUL, and SEP3, and slightly up-regulated the expression of upstream genes such as CO and GI. The above results indicated that CaFT and CjFT played a role in promoting flowering in both camellia species. The expression pattern of CaFT in leaves suggested that, compared to CjFT, CaFT may be related to the annual flowering of C. azalea.

Multifunctional Electrostatic Droplet Manipulation on the Femtosecond Laser-Prepared Slippery Surfaces.

A strategy to manipulate droplets on the lubricated slippery surfaces using tribostatic electricity is proposed. By employing femtosecond laser-induced porous microstructures, we prepared a slippery surface with ultralow adhesion to various liquids. Electrostatic induction causes the charges within the droplet to be redistributed; thus, the droplet on the as-prepared slippery surfaces can be guided by electrostatic force under the electrostatic field, with controllable sliding direction and unlimited transport distance. The combination of electrostatic interaction and slippery surfaces allows us to manipulate droplets with a wide volume range (from 100 nL to 0.5 mL), charged droplets (including electrostatic attraction and repulsion), corrosive droplets, and even organic droplets with ultralow surface tension. In addition, droplets on tilted surfaces, curved surfaces, and inverted slippery surfaces can also be manipulated. Especially, the slippery surfaces can even allow the electrostatic interaction to manipulate alcohol with surface tension as low as 22.3 mN/m and liquid droplets suspended on a downward surface, which is not possible with reported superhydrophobic substrates. The features of slippery surfaces make the electrostatic manipulation successfully applied in versatile droplet manipulation, droplet patterning, chemical microreaction, transport of solid cargo, targeted delivery of chemicals, and liquid sorting.

Resistance role of Lactobacillus sp. and Lactococcus sp. to copper ions in healthy children's intestinal microorganisms.

Heavy metal exposure is closely associated with gut microbe function and tolerance. However, intestinal microbe responses in children to different copper ion (Cu2+) concentrations have not yet been clarified. Here, in vitro cultivation systems were established for fecal microbe control and Cu2+-treated groups in healthy children. 16S rDNA high-throughput sequencing, meta-transcriptomics and metabolomics were used here to identify toxicity resistance mechanisms at microbiome levels. The results showed that Lactobacillus sp. and Lactococcus sp. exerted protective effects against Cu2+ toxicity, but these effects were limited by Cu2+ concentration. When the Cu2+ concentration was ≥ 4 mg/L, the abundance of Lactobacillus sp. and Lactococcus sp. significantly decreased, and the pathways of antioxidant activity and detoxification processes were enriched at 2 mg/L Cu2+, and beneficial metabolites accumulated. However, at high concentrations of Cu2+ (≥4 mg/L), the abundance of potential pathogen increased, and was accompanied by a downregulation of genes in metabolism and detoxification pathways, which meant that the balance of gut microbiota was disrupted and toxicity resistance decreased. From these observations, we identified some probiotics that are tolerant to heavy metal Cu2+, and warn that only when the concentration limit of Cu2+ in food is 2 mg/L, then a balanced gut microbiota can be guaranteed in children, thereby providing protection for their health.

Fluorinated TiO2 Hollow Spheres for Detecting Formaldehyde under UV Irradiation.

The fluorinated titanium dioxide (F-TiO2) hollow spheres with varying F to Ti molar ratios were prepared by a simple one-step hydrothermal method followed by thermal processing. The diameter of the F-TiO2-0.3 hollow spheres with a nominal ratio of F:Ti = 0.3:1 was about 200-400 nm. Compared with the sensor based on pristine TiO2 sensing materials, the F-TiO2-0.3 sensor displayed an enhanced sensing performance toward gaseous formaldehyde (HCHO) vapor at room temperature under ultraviolet (UV) light irradiation. The F-TiO2-0.3 sensor demonstrated an approximately 18-fold enhanced response (1.56) compared to the pristine TiO2 sensor (0.085). The response and recovery times of the F-TiO2-0.3 sensor to 10 ppm HCHO were about 56 s and 64 s, respectively, and a limit-of-detection value of 0.5 ppm HCHO was estimated. The F-TiO2-0.3 sensor also demonstrated good repeatability and selectivity to HCHO gas under UV light irradiation. The outstanding HCHO gas-sensing properties of the F-TiO2-0.3 sensor were related to the following factors: the excitation effect caused by the UV light facilitated surface chemical reactions with analyte gas species; the hollow sphere structure provided sufficient active sites; and the surface fluoride (≡Ti-F) created additional chemisorption sites on the surface of the TiO2 material.

Genomics insights into flowering and floral pattern formation: regional duplication and seasonal pattern of gene expression in Camellia.

BACKGROUND: The formation and domestication of ornamental traits are influenced by various aspects, such as the recognition of esthetic values and cultural traditions. Camellia japonica is widely appreciated and domesticated around the world mainly due to its rich variations in ornamental traits. Ornamental camellias have a diverse range of resources, including different bud variations from Camellia spp. as well as inter- and intra- specific hybridization. Despite research on the formation of ornamental traits, a basic understanding of their genetics and genomics is still lacking. RESULTS: Here, we report the chromosomal-level reference genome of C. japonica through combining multiple DNA-sequencing technologies and obtain a high-density genetic linkage map of 4255 markers by sequencing 98 interspecific F1 hybrids between C. japonica and C. chekiangoleosa. We identify two whole-genome duplication events in C. japonica: one is a shared ancient γ event, and the other is revealed to be specific to genus Camellia. Based on the micro-collinearity analysis, we find large-scale segmental duplication of chromosome 8, resulting to two copies of the AGAMOUS loci, which may play a key role in the domestication of floral shapes. To explore the regulatory mechanisms of seasonal flowering, we have analyzed year-round gene expression patterns of C. japonica and C. azalea-a sister plant of continuous flowering that has been widely used for cross breeding. Through comparative analyses of gene co-expression networks and annual gene expression patterns, we show that annual expression rhythms of some important regulators of seasonal growth and development, including GIGANTEA and CONSTANS of the photoperiod pathway, have been disrupted in C. azalea. Furthermore, we reveal that the distinctive expression patterns of FLOWERING LOCUS T can be correlated with the seasonal activities of flowering and flushing. We demonstrate that the regulatory module involved in GIGANTEA, CONSTANS, and FLOWERING LOCUS T is central to achieve seasonality. CONCLUSIONS: Through the genomic and comparative genomics characterizations of ornamental Camellia spp., we propose that duplication of chromosomal segments as well as the establishment of gene expression patterns has played a key role in the formation of ornamental traits (e.g., flower shape, flowering time). This work provides a valuable genomic platform for understanding the molecular basis of ornamental traits.

Targeting ZDHHC21/FASN axis for the treatment of diffuse large B-cell lymphoma.

S-palmitoylation is essential for cancer development via regulating protein stability, function and subcellular location, yet the roles S-palmitoylation plays in diffuse large B-cell lymphoma (DLBCL) progression remain enigmatic. In this study, we uncovered a novel function of the palmitoyltransferase ZDHHC21 as a tumor suppressor in DLBCL and identified ZDHHC21 as a key regulator of fatty acid synthetase (FASN) S-palmitoylation for the first time. Specifically, ZDHHC21 was downregulated in DLBCL, and its expression level was associated with the clinical prognosis of patients with DLBCL. In vitro and in vivo experiments suggested that ZDHHC21 suppressed DLBCL cell proliferation. Mechanistically, ZDHHC21 interacted with FASN and mediated its palmitoylation at Cys1317, resulting in a decrease in FASN protein stability and fatty acid synthesis, consequently leading to the inhibition of DLBCL cell growth. Of note, an FDA-approved small-molecule compound lanatoside C interacted with ZDHHC21, increased ZDHHC21 protein stability and decreased FASN expression, which contributed to the suppression of DLBCL growth in vitro and in vivo. Our results demonstrate that ZDHHC21 strongly represses DLBCL cell proliferation by mediating FASN palmitoylation, and suggest that targeting ZDHHC21/FASN axis is a potential therapeutic strategy against DLBCL.

Occurrence, source apportionment, and ecological risk of legacy and emerging per- and poly-fluoroalkyl substances (PFASs) in the Dahei river basin of a typical arid region in China.

Per- and poly-fluoroalkyl substances (PFASs) are artificial chemicals with broad commercial and industrial applications. Many studies about PFASs have been conducted in densely industrial and populated regions. However, fewer studies have focused on the PFASs' status in a typical arid region. Here, we investigated 30 legacy and emerging PFASs in surface water from the mainstream and tributaries of the Dahei River. Our results revealed that total PFASs concentrations (∑30PFASs) in water ranged from 3.13 to 289.1 ng/L (mean: 25.40 ng/L). Perfluorooctanoic acid (PFOA) had the highest mean concentration of 2.44 ng/L with a 100% detection frequency (DF), followed by perfluorohexanoic acid (PFHxA) (mean concentration: 1.34 ng/L, DF: 59.26%). Also, perfluorohexane sulfonate (DF: 44.44%), perfluorobutane sulfonate (DF: 88.89%), and perfluorooctane sulfonate (PFOS) (DF: 92.59%) had mean concentrations of 12.94, 2.00, and 1.05 ng/L, respectively. Source apportionment through ratio analysis and principal component analysis-multiple linear regression analysis showed that treated or untreated sewage, aqueous film-forming foam, degradation of precursors, and fluoropolymer production were the primary sources. The PFOS alternatives were more prevalent than those of PFOA. Conductivity, total phosphorus, and chlorophyll a positively correlated with Σ30PFASs and total perfluoroalkane sulfonates concentrations. Furthermore, ecological risk assessment showed that more attention should be paid to perfluorooctadecanoic acid, perfluorohexadecanoic acid, perfluorooctane sulfonate, perfluorohexane sulfonate, and (6:2 and 6:2/8:2) polyfluoroalkyl phosphate mono- and di-esters. The mass load of PFASs to the Yellow River was 1.28 kg/year due to the low annual runoff in the Dahei River in the arid region. This study provides baseline data for PFASs in the Dahei River that can aid in the development of effective management strategies for controlling PFASs pollution in typical arid regions in China.

Stretchable, Programmable and Magnet-Insensitive Protonic Display Based on Integrated Ionic Circuit.

As a new approach to "More than Moore", integrated ionic circuits serve as a possible alternative to traditional electronic circuits, yet the integrated ionic circuit composed of functional ionic elements and ionic connections is still challenging. Herein, a stretchable and transparent ionic display module of the integrated ionic circuit has been successfully prepared and demonstrated by pixelating a proton-responsive hydrogel. It is programmed to excite the hydrogel color change by a Faraday process occurring at the electrode at the specific pixel points, which enables the display of digital information and even color information. Importantly, the display module exhibits stable performance under strong magnetic field conditions (1.7 T). The transparent and stretchable nature of such ionic modules also allows them to be utilized in a broad range of scenarios, which paves the way for integrated ionic circuits.

SnTe/SnSe Heterojunction Based Ammonia Sensors with Excellent Withstand to Ambient Humidities.

Non-invasive breath testing has gained increasing importance for early disease screening, spurring research into cheap sensors for detecting trace biomarkers such as ammonia. However, real-life deployment of ammonia sensors remains hindered by susceptibility to humidity-induced interference. The SnTe/SnSe heterojunction-based chemiresistive-type sensor demonstrates an excellent response/recovery to different concentrations of ammonia from 0.1 to 100 ppm at room temperature. The improved sensing properties of the heterojunctions-based sensors compared to single-phased SnTe or SnSe can be attributed to the stronger NH3 adsorptions, more Te vacancies, and hydrophobic surface induced by the formed SnTe/SnSe heterojunctions. The sensing mechanisms are investigated in detail by using in situ techniques such as diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), Kelvin probe, and a.c. impedance spectroscopy together with the Density-Function-Theory calculations. The formed heterojunctions boost the overall charge transfer efficiency between the ammonia and the sensing materials, thus leading to the desirable sensing features as well, with excellent resistance to ambient humidities.

Coupled Precipitation of Dual-Nanoprecipitates to Optimize Microstructural and Mechanical Properties of Cast Al-Cu-Mg-Mn Alloys via Modulating the Mn Contents.

The effect of Mn content on the microstructure evolution and mechanical properties of Al-Cu-Mg-x Mn alloys at ambient temperature was investigated. The findings show that in the Mn-containing alloys at the as-cast state, the blocky primary T(Al20Cu2Mn3) phase coexisting with the Al2Cu phase appeared. With the increase in Mn content, the majority of the Al2Cu phase dissolved, nd a minor amount of the T phase remained at the grain boundary after solution treatment. The rod-like TMn (Al20Cu2Mn3) nanoprecipitate was simultaneously distributed at grain boundaries and the interiors, while a high density of needle-like θ″ (Al3Cu) nanoprecipitate was also observed in the T6 state. Further increases in Mn content promoted the dispersion of the TMn phase and inhibited the growth and transformation of the θ″ phase. Tensile test results show that 0.7 wt.% Mn alloy had excellent mechanical properties at ambient temperature with ultimate tensile strength, yield strength, and fracture elongation of 498.7 MPa, 346.2 MPa, and 19.2%, respectively. The subsequent calculation of strengthening mechanisms elucidates that precipitation strengthening is the main reason for the increase in yield strength of Mn-containing alloys.

FgSdhC Paralog Confers Natural Resistance toward SDHI Fungicides in Fusarium graminearum.

Fusarium graminearum exhibited natural resistance to a majority of succinate dehydrogenase inhibitor fungicides (SDHIs) and the molecular mechanisms responsible for the natural resistance were still unknown. Succinate dehydrogenase subunit C (SdhC) is an essential gene for maintaining succinate-ubiquinone oxidoreductase (SQR) function in fungi. In F. graminearum, a paralog of FgSdhC named as FgSdhC1 was identified. Based on RNA-Seq and qRT-PCR assay, we found that the expression level of FgSdhC1 was very low but upregulated by SDHIs treatment. Based on reverse genetics, we demonstrated that FgSdhC1 was an inessential gene in normal growth but was sufficient for maintaining SQR function and conferred natural resistance or reduced sensitivity toward SDHIs. Additionally, we found that the standard F. graminearum isolate PH-1 had high sensitivity to a majority of SDHIs. A single nucleotide variation (C to T) in the FgSdhC1 of isolate PH-1, resulting in a premature termination codon (TAA) replacing the fourth amino acid glutamine (Q), led to the failure of FgSdhC1 to perform functions of conferring nature resistance. These results established that a dispensable paralogous gene determined SDHIs resistance in natural populations of F. graminearum.

Histone deacetylase 9 plays a role in sevoflurane-induced neuronal differentiation inhibition by inactivating cAMP-response element binding protein transcription and inhibiting the expression of neurotrophin-3.

Postoperative cognitive decline (POCD) is a common and serious complication following anesthesia and surgery; however, the precise mechanisms of POCD remain unclear. Our previous research showed that sevoflurane impairs adult hippocampal neurogenesis (AHN) and thus cognitive function in the aged brain by affecting neurotrophin-3 (NT-3) expression; however, the signaling mechanism involved remains unexplored. In this study, we found a dramatic decrease in the proportion of differentiated neurons with increasing concentrations of sevoflurane, and the inhibition of neural stem cell differentiation was partially reversed after the administration of exogenous NT-3. Understanding the molecular underpinnings by which sevoflurane affects NT-3 is key to counteracting cognitive dysfunction. Here, we report that sevoflurane administration for 2 days resulted in upregulation of histone deacetylase 9 (HDAC9) expression, which led to transcriptional inactivation of cAMP-response element binding protein (CREB). Due to the colocalization of HDAC9 and CREB within cells, this may be related to the interaction between HDAC9 and CREB. Anyway, this ultimately led to reduced NT-3 expression and inhibition of neural stem cell differentiation. Furthermore, knockdown of HDAC9 rescued the transcriptional activation of CREB after sevoflurane exposure, while reversing the downregulation of NT-3 expression and inhibition of neural stem cell differentiation. In summary, this study identifies a unique mechanism by which sevoflurane can inhibit CREB transcription through HDAC9, and this process reduces NT-3 levels and ultimately inhibits neuronal differentiation. This finding may reveal a new strategy to prevent sevoflurane-induced neuronal dysfunction.

Effect of lactic acid bacteria by different concentrations of copper based on non-target metabolomic analysis.

Copper (Cu) is an essential element for mammals, but excess intake can have detrimental health consequences. However, Cu is no longer present in the "Limit of Contaminants in Foods" promulgated in 2022. The potential impact of different Cu (II) concentrations on human health remains unclear. In this study, a strain of lactic acid bacteria (LAB), namely, Lactiplantibacillus plantarum CICC 23121 (L23121), was selected as a prebiotic indicator strain to indirectly assess the effects of food-limited Cu (II) concentrations (issued by Tolerance limit of copper in foods in 1994) on the functions of intestinal microbes. We used non-target metabolomics, automatic growth curve detector, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) to investigate the effects of Cu (II) on L23121. The study revealed shows that the 50% minimum inhibitory concentration (MIC50) of Cu (II) for most lactic acid bacteria was 4 mg/L. At low Cu (II) concentrations (≤ 4 mg/L), the pentose phosphate pathway and pyrimidine metabolism of the lactic acid bacteria were affected, resulting in a decrease in the content of beneficial secondary metabolites and a significant decrease in the cell activity. As Cu (II) concentrations increase (≥ 6 mg/L), the key amino acid and lipid metabolisms were affected, leading to the inhibition of growth and primary metabolite production of the bacteria. Under high concentration of Cu (II) (6 mg/L), the surface adhesion of the bacteria was distorted and covered with significantly large particles, and the functional groups of the cells were significantly shifted. As a probiotic, the abundance of lactic acid bacteria in the intestine is significantly reduced, which will inevitably seriously damage intestinal homeostasis. Thus, to protect human intestinal microbes' health, it is recommended to limit the concentration of Cu in food to less than 4 mg/L.