Acid Treatment Research Articles

A universal strategy towards high-rate and ultralong-life of Li‐rich Mn‐based cathode materials

Lithium-rich manganese-based cathode materials (LRMs) have shown promise for the next-generation lithium battery cathodes due to their high discharge specific capacity (∼250 mAh g−1) and wide operating voltage range (2.0–4.8 V). However, these materials face limitations such as low initial Coulombic efficiency (ICE), poor cycle stability, and inadequate rate capability. To address these challenges, we employed a simple citric acid treatment (CA-treatment) method to fabricate the Li-rich spinel coating layer on LRMs. This in situ formed spinel Li4Mn5O12 layer successfully suppresses the oxygen release, provides three-dimensional (3D) lithium-ion diffusion channels and enriches Li embedding sites, resulting in a substantial improvement in the rate capability and high-rate cycling performance. The modified LRM delivers a high specific capacity of 193.7 mAh g−1 at 2.0 C and 154.8 mAh g−1 at 5.0 C, after 1000 cycles at 10.0 C, 77.4 % capacity retention with 102.5 mAh g−1 is realized. This facile CA-treatment benefits the electrochemical properties of LRMs comparable to those of altering the microscopic morphology. This work offers a new avenue for exploring outstanding LRMs with high-rate and ultralong cycling life.

Foliar application of salicylic acid improved morpho-anatomical features of potato by irrigating with wastewater

BackgroundThis study aimed to evaluate the suitability of using drain water as a source of irrigation and its effects along with salicylic acid on morphological, anatomical, physico-chemical as well as yield attributes of potato. For this study, potato tubers were grown in pots and irrigated with different concentrations of drain water. Salicylic acid treatments vis. 0, 0.5 and 1.0 mM were applied foliarly. Pre- and post-harvest analysis was carried out to determine different attributes of soil, water and plants after 60 days.ResultsThe growth of potato plant was increased as the concentration of SA increased through increasing shoot length, fresh/dry weight and tuber number/plant. In this research work, plant respond to overcome metal stresses by up regulating antioxidant defense system such as, peroxidase, catalase and superoxide dismutase) by application of highest treatment of SA when irrigated with 6% drain water. Plants accumulated the highest concentrations of Cd, Cr, and Pb in the leaves when treated with 1 mM of SA, compared to other plant parts. It was observed that photosynthetic pigment enhanced in 6% drain water treated plants when applied with 1mM SA as compared to control. An increase in epidermis and cortical cell thickness, as well as stomatal closure, was observed, helping to maintain water loss under stress conditions.ConclusionsAccording to these results, it can be suggested that SA is potent signaling molecule can play an essential role in maintaining potato growth when irrigated with drain water containing heavy metals through stimulating metal up take and up regulation of antioxidant enzymes.

Reaction of β -Ketoester and 1,3-Diol to Access Chemically Recyclable and Mechanically Robust Poly(vinyl alcohol) Thermosets through Incorporation ofβ -(1,3-dioxane)ester.

The development of mechanically robust, chemically stable, and yet recyclable polymers represents an essential undertaking in the context of advancing a circular economy for plastics. We introduce a novel cleavableβ-(1,3-dioxane)ester (DXE) linkage, synthesized through the catalyst-free reaction ofβ-ketoester and 1,3-diol, to cross-link poly(vinyl alcohol) (PVA) for the formation of high-performance thermosets with inherent chemical recyclability. PVA, modified withβ-ketoester through the transesterification reaction with excess tert-butyl acetoacetate, cross-linkswith the unmodified 1,3-diols within PVA itself upon thermal treatment. Cross-linking improves PVA's mechanical properties, with Young's modulus and toughness that reach up to 656 MPa and 84 MJ cm-3, i.e. 3- and 12-fold those of linear PVA. Thermal treatment of the cross-linked PVA under acid conditions leads to deconstruction of the networks, allowing the almost PVA excellent recovery (> 90%) . In the absence of thermal or acidic treatment, cross-linked PVA maintains its dimensional stability. We show that the recovery of PVA is also possible when the treatment is performed in the presence of other plastics commonly found in recycling mixtures. Furthermore, PVA-based composites comprising carbon fibers and activated charcoal cross-linked by the DXE linkages are also shown to be recyclable with recovery of the PVA and the fillers.

Ultrasonic‐assisted activation of clay for efficient removal of U(VI) and Cr(VI)

AbstractThe natural clay mineral was activated using the acid treatment under ultrasonic conditions to improve its adsorption performance. The acid‐activated clay (AAC) was investigated to remove Cr(VI) from wasted lubricant and U(VI) from aqueous solution by batch, spectroscopy, and modeling. Batch experiments showed that the isotherms and adsorption kinetics of Cr(VI)/U(VI) on AAC were satisfactorily followed by Frenudlich and the pseudo‐second‐order model, respectively. The decreased adsorption of U(VI) on AAC with the increase of ion strength indicated the outer surface complexation of U(VI) on AAC. The interaction mechanism of Cr(VI)/U(VI) on AAC was demonstrated to be surface complexation by oxygenated functional groups (e.g., hydroxyl) according to X‐ray photoelectron spectroscopy (XPS) analysis. According to fitting of surface complexation models using three approaches, the adsorption of U(VI) on AAC at different pH can be better fitted by the double‐layer model compared to the constant‐capacitance model and triple‐layer model. These findings are great important for the application of acid activated clay in the removal of heavy metals and radionuclides from the environment.

Reaction of β‐Ketoester and 1,3‐Diol to Access Chemically Recyclable and Mechanically Robust Poly(vinyl alcohol) Thermosets through Incorporation of β‐(1,3‐dioxane)ester

The development of mechanically robust, chemically stable, and yet recyclable polymers represents an essential undertaking in the context of advancing a circular economy for plastics. We introduce a novel cleavable β‐(1,3‐dioxane)ester (DXE) linkage, synthesized through the catalyst‐free reaction of β‐ketoester and 1,3‐diol, to cross‐link poly(vinyl alcohol) (PVA) for the formation of high‐performance thermosets with inherent chemical recyclability. PVA, modified with β‐ketoester through the transesterification reaction with excess tert‐butyl acetoacetate, cross‐links with the unmodified 1,3‐diols within PVA itself upon thermal treatment. Cross‐linking improves PVA’s mechanical properties, with Young’s modulus and toughness that reach up to 656 MPa and 84 MJ cm‐3, i.e. 3‐ and 12‐fold those of linear PVA. Thermal treatment of the cross‐linked PVA under acid conditions leads to deconstruction of the networks, allowing the almost PVA excellent recovery (> 90%) . In the absence of thermal or acidic treatment, cross‐linked PVA maintains its dimensional stability. We show that the recovery of PVA is also possible when the treatment is performed in the presence of other plastics commonly found in recycling mixtures. Furthermore, PVA‐based composites comprising carbon fibers and activated charcoal cross‐linked by the DXE linkages are also shown to be recyclable with recovery of the PVA and the fillers.

Dope dyeing of tannic acid modified ultra‐high molecular weight polyethylene fabric

AbstractIn this study, we examined dyeing behavior of tannic acid modified ultra high molecular weight polyethylene fabric. Whole study was conducted to see the effect of tannic acid on dope dyeing performance of the fabric. Tannic acid and its complex with sodium salt TA‐Na+ complex were used for pretreatment. After dope dyeing, the color strength of fabrics, color fastness, surface morphology, and fiber structure were characterized by k/s value, color difference, scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR), respectively. The effect of treatment conditions was also discussed. The results had shown better color strength and washing fastness were obtained after tannic acid treatment, especially after TA‐Na+ complex treatment. SEM observation indicated the tannic acid adhesion on fabric surface. Both EDS and FTIR results showed the enhancement of surface polarity. And the UHMWPE fabric treated with 1% (w/v) TA‐Na+ with pH ranging 4–5 for 6 h showed better color durability over time. Approach was suitable because of sustainable, green behavior of tannic acid and entire process had a low cost.

SENSITIVE TO FREEZING2 is crucial for growth of Marchantia polymorpha under acidic conditions.

Land plants have evolved many systems to adapt to a wide range of environmental stresses. In seed plants, oligogalactolipid synthesis is involved in tolerance to freezing and dehydration, but it has not been analyzed in non-vascular plants. Here we analyzed trigalactosyldiacylglycerol (TGDG) synthesis in Marchantia polymorpha. TGDG is synthesized by galactolipid: galactolipid galactosyltransferase [GGGT; SENSITIVE TO FREEZING2 (SFR2) in Arabidopsis]. We analyzed the subcellular localization and GGGT activity of two M. polymorpha SFR2 homologs (MpGGGT1 and MpGGGT2, each as a GFP-fusion protein) using a transient expression system in Nicotiana benthamiana leaves and found that MpGGGT1-GFP localized in the chloroplast envelope membrane. We produced mutants Mpgggt1 and Mpgggt2 and found that TGDG did not accumulate in Mpgggt1 upon treatment of the thallus with acetic acid. Moreover, growth of Mpgggt1 mutants was impaired by acetic acid treatment. Microscopy revealed that the acetic acid treatment of M. polymorpha plants damaged intracellular membranes. The fact that the effect was similar for wild-type and Mpgggt1 plants suggested that MpGGGT has a role in recovery from damage. These results indicate that MpGGGT plays a crucial role in M. polymorpha growth under conditions of acid stress, which may have been encountered during the ancient terrestrial colonization of plants.

Nrf2/ASPM axis regulated vasculogenic mimicry formation in hepatocellular carcinoma under hypoxia.

Hypoxic microenvironment is a common feature of most solid tumors including hepatocellular carcinoma (HCC). Vasculogenic mimicry (VM) formation by tumor cells could provide blood supply to tumor cells under hypoxia. NFE2 like basic leucine zipper (bZIP) transcription factor 2 (Nrf2), a regulator of cellular homeostasis, may promote tumor progression in the hypoxic conditions. However, the role and regulatory mechanisms of Nrf2 in HCC are not fully elucidated. Nrf2 and assembly factor for spindle microtubules (ASPM) expression modulations were conducted by lentiviral transfections. Western blot, immunofluorescence, ChIP-qPCR, dual-luciferase reporter gene assay, flow cytometry, RNA sequencing, multiple bioinformatics databases analysis, cell function assays in vitro, mouse model in vivo and human HCC tissues were employed to assess the effect of Nrf2/ASPM axis on HCC progression under hypoxia. Nrf2 and ASPM expression facilitated epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs) feature, and VM formation of HCC cells under hypoxia. Furthermore, Nrf2-regulated ASPM expression, via binding directly to the promoter region of ASPM and transcriptionally promoting ASPM expression. ASPM re-expression in Nrf2 knockdown cells or ASPM knockdown in Nrf2 overexpression cells reversed the cellular function caused by Nrf2. Meantime, retinol metabolism pathway was disrupted following abnormal ASPM expression. Nrf2/ASPM axis in murine models accelerated tumor growth and VM, corroborating in vitro findings. All-trans retinoic acid treatment reversed stemness and VM of HCC cells in vitro and in vivo. Clinically, Nrf2 and ASPM expressions were related to poor prognosis of HCC patients. Nrf2 drives EMT, CSCs characteristics and VM in HCC under hypoxia through the modulation of ASPM. Retinol metabolism pathway was dysregulated in HCC cells with ASPM overexpression. Nrf2/ASPM axis and related pathway provided potential therapeutic target for HCC.

Cardiovascular and Renal Effects Induced by Alpha-Lipoic Acid Treatment in Two-Kidney-One-Clip Hypertensive Rats

α-Lipoic acid (LA) is an antioxidant of endogenous production, also obtained exogenously. Oxidative stress is closely associated with hypertension, which causes kidney injury and endothelial dysfunction. Here, we evaluated the cardiovascular and renal effects of LA in the two-kidney-one-clip (2K1C) hypertension model. The rats were divided into four groups: Sham surgery (Sham), the two-kidneys-one-clip (2K1C) group, and groups treated with LA for 14 days (Sham-LA and 2K1C-LA). No changes were observed in the pattern of food, water intake, and urinary volume. The left/right kidney weight LKw/RKw ratio was significantly higher in 2K1C animals. LA treatment did not reverse the increase in cardiac mass. In relation to vascular reactivity, there was an increase in the potency of phenylephrine (PHE) curve in the hypertensive animals treated with LA compared to the 2K1C group and also compared to the Sham group. Vasorelaxation induced by acetylcholine (Ach) and sodium nitroprusside (SNP) were not improved by treatment with LA. Urea and creatinine levels were not altered by the LA treatment. In conclusion, the morphological changes in the aorta and heart were not reversed; however, the treatment with LA mitigated the contraction increase induced by the 2K1C hypertension.

Interfacial Engineering of Mn Porphyrin/Au Electrodes for Identifying MnOx as the Active Species under Oxygen Evolution Reactions.

Understanding the influence of surface structural features at a molecular level is beneficial in guiding an electrode's mechanistic proposals for electrocatalytic reactions. The relationship between structural stability and catalytic activity significantly impacts reaction performance, even though atomistic knowledge of active sites remains a topic of discussion. In this context, this work presents scanning tunneling microscopy (STM) results for the highly ordered arrangement of manganese porphyrin molecules on a Au(111) surface; STM allows us to monitor active sites at a molecular level to focus on long-standing issues with the electrocatalytic process, especially the exact nature of the real active sites at the interfaces. After water oxidation, manganese porphyrin rapidly decomposes into active catalytic species as bright protrusions. These newly formed active species drastically lost catalytic activity, up to 82%, through only acid treatment, one of the oxide removal methods, not by deionized water and acetone treatments. STM results of the obviated active species on the Au surface by an acidic solution support the forfeited catalytic activity. In addition, it shows a 67% decrement in catalytic activity by adsorption of phosphonic acid, one of the oxide's preferred adsorption materials, compared to the pristine one. Based on these observations, we confirm that the newly formed active species, as water oxidation catalysts, mostly consist of manganese oxides. Notable findings of our work provide molecular evidence for the active sites of Au and modified Au electrodes that spur the future development of water oxidation catalysts.

Abscisic acid treatment positively regulates suberin polyaliphatics biosynthesis at wound sites in postharvest yam tubers

Suberin polyaliphatics (SPA) accumulation on the closing layer plays a significant role in wound healing of fruit and vegetables. However, no literature is available on abscisic acid (ABA) effect on yam tuber healing in relation to SPA biosynthesis. In this study, ABA treatment decreased weight loss and disease incidence of yam tubers, maintained the integrity of cell membrane, and promoted the accumulation and polymerization of SPA monomers such as fatty acids (FAs), ω-hydroxyacid (ω-OHA) and α, ω-dicarboxylic acid (α, ω-diA). Gene expression of β-ketoacyl CoA synthases (DoKCS2, DoKCS6), cytochrome P450 fatty acid ω-hydroxylases (DoCYP86A1, DoCYP94B3), Glycerol-3-phosphate acyltransferases (DoDPAT5, DoGPAT7) and feruloyl-CoA transferase (DoFHT), which were associated with the biosynthesis of SPA monomers, were enhanced by ABA treatment. ABA improved gene expression of ATP-binding cassette transporters (DoABCG2, DoABCG6) and GDSL-type esterase/lipases (DoGELP38, DoGELP51, DoGELP96), which might facilitate the transport and polymerization of SPA monomers. Contrarily, applied fluridone (FLD, an inhibitor of ABA biosynthesis) exhibited an opposite effect to ABA treatment. The results indicate that ABA accelerates yam tuber healing via positively regulating SPA biosynthesis.

Retinoic acid generates a beneficial microenvironment for liver progenitor cell activation in acute liver failure.

When massive necrosis occurs in acute liver failure (ALF), rapid expansion of HSCs called liver progenitor cells (LPCs) in a process called ductular reaction is required for survival. The underlying mechanisms governing this process are not entirely known to date. In ALF, high levels of retinoic acid (RA), a molecule known for its pleiotropic roles in embryonic development, are secreted by activated HSCs. We hypothesized that RA plays a key role in ductular reaction during ALF. RNAseq was performed to identify molecular signaling pathways affected by all-trans retinoid acid (atRA) treatment in HepaRG LPCs. Functional assays were performed in HepaRG cells treated with atRA or cocultured with LX-2 cells and in the liver tissue of patients suffering from ALF. Under ALF conditions, activated HSCs secreted RA, inducing RARα nuclear translocation in LPCs. RNAseq data and investigations in HepaRG cells revealed that atRA treatment activated the WNT-β-Catenin pathway, enhanced stemness genes (SOX9, AFP, and others), increased energy storage, and elevated the expression of ATP-binding cassette transporters in a RARα nuclear translocation-dependent manner. Further, atRA treatment-induced pathways were confirmed in a coculture system of HepaRG with LX-2 cells. Patients suffering from ALF who displayed RARα nuclear translocation in the LPCs had significantly better MELD scores than those without. During ALF, RA secreted by activated HSCs promotes LPC activation, a prerequisite for subsequent LPC-mediated liver regeneration.

TMK4-mediated phosphorylation of FIP37 regulates auxin-triggered N6-methyladenosine mRNA modification of auxin biosynthetic genes in Arabidopsis

The dynamics of N6-methyladenosine (m6A) mRNA modification are tightly controlled by the m6A methyltransferase complex and demethylases. Here, we find that auxin treatment alters m6A modification on auxin-responsive genes. Mechanically, TRANSMEMBRANE KINASE 4 (TMK4), a component of the auxin signaling pathway, interacts with and phosphorylates FKBP12-INTERACTING PROTEIN 37 (FIP37), a core component of the m6A methyltransferase complex, in an auxin-dependent manner. Phosphorylation of FIP37 enhances its interaction with RNA, thereby increasing m6A modification on its target genes, such as NITRILASE 1 (NIT1), a gene involved in indole-3-acetic acid (IAA) biosynthesis. 1-Naphthalacetic acid (NAA) treatment accelerates the mRNA decay of NIT1, in a TMK4- and FIP37-dependent manner, which leads to inhibition of auxin biosynthesis. Our findings identify a regulatory mechanism by which auxin modulates m6A modification through the phosphorylation of FIP37, ultimately affecting mRNA stability and auxin biosynthesis in plants.

Mechanical and tribological characterization of vacuum pressurized impregnation (VPI) treated bamboo fiber-reinforced polymer (FRP) composites with jute mat layer under fretting wear conditions

ABSTRACT The study explored the performance of VPI-treated bamboo fiber reinforced FRP laminated composites, focusing on fretting wear and mechanical behavior with various chemical treatments. FTIR analysis revealed that NaOH treatment effectively removed hemicelluloses and lignin, with peak shifts at 3330, 2918, and 1420 cm−1, while tannic acid induced peak shifts at 1640 and 1500 cm−1, indicating cellulose interactions. Phosphoric acid treatment reduced intensity at 3340 and 2890 cm−1, suggesting cellulose depolymerization. TGA showed varied weight loss profiles, reflecting thermal property modifications. XRD analysis indicated changes in crystalline structure, and SEM revealed structural alterations. Tensile strengths at 0.5% weight were 216 ± 3.0 MPa for alkaline-treated bamboo fiber composite (A-BFC), 256 ± 0.01 MPa for tannic acid-treated bamboo fiber composite (T-BFC), and 281 ± 3.0 MPa for phosphoric acid-treated bamboo fiber composite (P-BFC). Fretting wear analysis demonstrated that P-BFC withstood loads up to 45N, with wear resistance improving with increased fiber content. dynamic mechanical analysis (DMA) highlighted that P-BFC exhibited the highest initial storage modulus and a tan δ peak of 69°C, compared to T-BFC and A-BFC, both at 68°C. The wear rate decreased with higher bamboo fiber content and load, showcasing the potential of VPI-treated bamboo fiber composites for applications requiring enhanced strength and wear resistance.

Is Pt dissolution a concern from the counter electrode in electrochemical oxygen evolution reaction?

The Pt metal and its oxides dissolution from the counter electrode (CE, in hydrogen evolution reaction (HER)) has been suspected to affect the non-noble metal catalysts toward oxygen evolution reaction (OER). However, little effort has been devoted to this concern, and this work aims to determine the effect. The influence of electrolytes (H2SO4 and NaOH) and Pt CE (acid-treated and pristine) on the Pt dissolution and membrane separations (Nafion and PiperION) on preventing Pt species migration were evaluated. The results indicate only 11.2 ppb Pt from the cathodic electrolyte with Nafion 211 and 5 M NaOH electrolyte is observed, and no Pt is found from all other samples with acid-treated Pt CE. Regarding pristine Pt CE, 0.4 and 4.4 ppb Pt are observed from 0.5 M H2SO4 and 5 M NaOH electrolytes, respectively. The findings in this work include: (1) Nafion membrane can effectively prevent the migration of Pt species from the cathode to the anode side; (2) a simple acid treatment of Pt could minimize the Pt dissolution into the acid electrolyte while showing an opposite role in the alkaline electrolyte; (3) the Pt dissolution from all experiments is minor, indicating Pt is a suitable CE for OER.

TCO-free quantum dot light-emitting diodes based on PEDOT:PSS electrode treated with mild acid

Poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) has emerged as a promising candidate for high-cost transparent conductive oxide (TCO) electrodes. However, achieving high conductivity in PEDOT:PSS typically requires treatment with strong acids, which presents inherent risks. In this study, we propose an alternative approach utilizing a mild methane sulfonic acid (MSA) treatment for PEDOT:PSS as a transparent conductive electrode (TCE). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses unveil heightened phase separation between PEDOT and PSS by MSA treatment, accompanied by structural modifications in PEDOT. Moreover, the interfacial morphology between the MSA-treated electrode and the hole injection layer underwent significant changes. It is precisely this improved interface morphology, combined with enhanced conductivity, that significantly improves the efficiency of the obtained TCO-free blue quantum dot light-emitting diode (QLED) by 300 % compared to the reference device. Finally, leveraging the high performance of the TCO-free blue QLEDs, we fabricate the above device on a yellow-emissive phosphors-in-glass substrate, enabling a white light-emitting LED (WLED) device. This experiment not only elucidates the structural changes in PEDOT:PSS under mild acid treatment but also introduces an innovative strategy for developing high-performance PEDOT:PSS electrodes.

The interaction of light with oxygen-vacancy-rich W18O49 nanoparticles synthesized using different acid molarities for acidic and neutral water treatments

Toxic industrial compounds as a global difficulty can adversely impact people's health and the environment which motivates studies on the interaction of light and metal oxide nanoparticles to treat the water through adsorption or photocatalysis mechanism by nanoparticles. In the paper, oxygen-vacancy-rich W18O49 nanorods are successfully synthesized by a facile one-pot hydrothermal method using different molarities of hydrochloric acid (HCl) (2–12 M) as proposed candidates to treat the wastewater and solve the global difficulty related to treating the acidic water. The results declare that the change in acid molarity leads to noteworthy changes in the characteristic properties of the produced W18O49 nanorods, and the lowest acid molarity (2 M) causes the formation of uniform and pure monoclinic W18O49 nanorods with the high specific surface area (SSA) of 51.33 m2/g. Furthermore, the nanorods exhibit indirect and direct band gap energies in the range of 2.52–2.68 eV and 2.54–3.08 eV, respectively, as influenced by varying acid molarities (2–12 M). Furthermore, the impressive effects of acid molarity on the methylene blue removal efficiency of the nanorods under ultraviolet (UV) light are observed. The highest efficiency is obtained for W18O49 nanorods synthesized using the acid molarity of 2 M which can be explained by its high SSA, small band gap energy, generation of a large number of electron-hole pairs, and its efficient charge separation. The efficiencies of water treatment reach up to 99 % and 99.5 % at pH of 7 and 5, respectively, which is an excellent achievement and leads to proposing the mentioned W18O49 nanorods as an excellent candidate for treating wastewater and acid factory effluent which represents an appreciable breakthrough in addressing the issue.

Characterization of Mild Acid Stress Response in an Engineered Acid-Tolerant Escherichia coli Strain

Engineering acid-tolerant microbial strains is a cost-effective approach to overcoming acid stress during industrial fermentation. We previously constructed an acid-tolerant strain (Escherichia coli SC3124) with enhanced growth robustness and productivity under mildly acidic conditions by fine-tuning the expression of synthetic acid-tolerance module genes consisting of a proton-consuming acid resistance system (gadE), a periplasmic chaperone (hdeB), and ROS scavengers (sodB, katE). However, the precise acid-tolerance mechanism of E. coli SC3124 remained unclear. In this study, the growth of E. coli SC3124 under mild acid stress (pH 6.0) was determined. The final OD600 of E. coli SC3124 at pH 6.0 was 131% and 124% of that of the parent E. coli MG1655 at pH 6.8 and pH 6.0, respectively. Transcriptome analysis revealed the significant upregulation of the genes involved in oxidative phosphorylation, the tricarboxylic acid (TCA) cycle, and lysine-dependent acid-resistance system in E. coli SC3124 at pH 6.0. Subsequently, a weighted gene coexpression network analysis was performed to systematically determine the metabolic perturbations of E. coli SC3124 with mild acid treatment, and we extracted the gene modules highly associated with different acid traits. The results showed two biologically significant coexpression modules, and 263 hub genes were identified. Specifically, the genes involved in ATP-binding cassette (ABC) transporters, oxidative phosphorylation, the TCA cycle, amino acid metabolism, and purine metabolism were highly positively associated with mild acid stress responses. We propose that the overexpression of synthetic acid-tolerance genes leads to metabolic changes that confer mild acid stress resistance in E. coli. Integrated omics platforms provide valuable information for understanding the regulatory mechanisms of mild acid tolerance in E. coli and highlight the important roles of oxidative phosphorylation and ABC transporters in mild acid stress regulation. These findings offer novel insights to better the design of acid-tolerant chasses to synthesize value-added chemicals in a green and sustainable manner.

Exploring the feasibility of a single-protoplast proteomic analysis

BackgroundRecent advances in high-resolution mass spectrometry have now enabled the study of proteomes at the single-cell level, offering the potential to unveil novel aspects of cellular processes. Remarkably, there has been no prior attempt to investigate single-plant cell proteomes. In this study, we aimed to explore the feasibility of conducting a proteomic analysis on individual protoplasts.FindingsAs a result, our analysis identified 978 proteins from the 180 protoplasts, aligning with well-known biological processes in plant leaves, such as photosynthetic electron transport in photosystem II. Employing the SCP package in the SCoPE2 workflow revealed a notable batch effect and extensive missing values in the data. Following correction, we observed the heterogeneity in single-protoplast proteome expression. Comparing the results of single-protoplast proteomics with those of bulk leaf proteomics, we noted that only a small fraction of bulk data was detected in the single-protoplast proteomics data, highlighting a technical limitation of the current single-cell proteomics method.ConclusionsIn summary, we demonstrated the feasibility of conducting a single-protoplast proteomic experiment, revealing heterogeneity in plant cellular proteome expression. This underscores the importance of analyzing a substantial number of plant cells to discern statistically significant changes in plant cell proteomes upon perturbation such as abscisic acid treatment in future studies. We anticipate that our study will contribute to advancing single-protoplast proteomics in the near future.

Organic acid treatments on citrus insoluble dietary fibers and the corresponding effects on starch in vitro digestion

Three environmentally friendly organic acids, acetic acid, citric acid and oxalic acid, were used to treat citrus insoluble dietary fiber (CIDF) in present study, aiming to explore the changes in structural properties as well as their inhibitory effects on starch digestion. The results showed that organic acid treatment significantly reduced the particle size of all three CIDFs, with rougher and folded surfaces, improved crystallinity and thermal stability. During in vitro digestion, it was found that organic acid treatment could increase the particle size and viscosity of digestion, and also effectively enhance the inhibitory ability of α-glucosidase activity, resulting in a further blockage of starch digestion. The starch digestion in oxalic acid-treated group (with 3 wt% addition) was significantly reduced by 18.72 % compared to blank group and 9.05 % compared to untreated. These findings provide evidence of the potential of organic acid-treated insoluble dietary fiber as a functional food.