Application of environmental DNA metabarcoding to identify fish community characteristics in subtropical river systems.

Fish are vital in river ecosystems; however, traditional investigations of fish usually cause ecological damage. Extracting DNA from aquatic environments and identifying DNA sequences offer an alternative, noninvasive approach for detecting fish species. In this study, the effects of environmental DNA (eDNA), coupled with PCR and next-generation sequencing, and electrofishing for identifying fish community composition and diversity were compared. In three subtropical rivers of southern China, fish specimens and eDNA in water were collected along the longitudinal (upstream-downstream) gradient of the rivers. Both fish population parameters, including species abundance and biomass, and eDNA OTU richness grouped 38 sampling sites into eight spatial zones with significant differences in local fish community composition. Compared with order-/family-level grouping, genus-/species-level grouping could more accurately reveal the differences between upstream zones I-III, midstream zones IV-V, and downstream zones VI-VIII. From the headwaters to the estuary, two environmental gradients significantly influenced the longitudinal distribution of the fish species, including the first gradient composed of habitat and physical water parameters and the second gradient composed of chemical water parameters. The high regression coefficient of alpha diversity between eDNA and electrofishing methods as well as the accurate identification of dominant, alien, and biomarker species in each spatial zone indicated that eDNA could characterize fish community attributes at a level similar to that of traditional approaches. Overall, our results demonstrated that eDNA metabarcoding can be used as an effective tool for revealing fish composition and diversity, which is important for using the eDNA technique in aquatic field monitoring.

Methyl Acetate Boosts the Low-Temperature Performance of Li4Ti5O12/Graphite Dual-Ion Batteries.

Methyl acetate (MA) is a suitable solvent for low-temperature electrolyte solutions, but its poor stability against lithium metal is a big problem. Herein, a simple and cheap solution of LiPF6 dissolved in MA was successfully employed for Li4Ti5O12/graphite dual-ion batteries (DIBs). This cell has a long cycle life with 93.1% capacity retention after 1000 cycles. Moreover, it has superior performance at low temperatures (-40 °C) compared to other reported DIBs. The storage behavior of PF6- solvated by MA in graphite cathode has been investigated in detail by in situ X-ray diffraction (XRD) in combination with electrochemical dilatometry (ECD).

Surface Reconstruction for Selective Oxidation of Tetrahydroisoquinoline.

Integration of hydrogen evolution with the oxidation of organic substances in one electrochemical system is highly desirable. However, achieving selective oxidation of organic substances in the integrated system is still highly challenging. In this study, a phosphorylated NiMoO4 nanoneedle-like array was designed as the catalytic active electrode for the integration of highly selective electrochemical dehydrogenation of tetrahydroisoquinolines (THIQs) with hydrogen production. The leaching of anions, including MoO42- and PO43-, facilitates the reconstruction of the catalyst. As a result, nickel oxyhydroxides with the doping of PO43- and richness of defects are in situ formed. In situ Raman and density functional theory calculations have shown that the high catalytic activity is attributed to the in situ formed PO43- involved NiOOH substance. In the dehydrogenation process, the involved C-H bond but not the N-H bond is first destroyed. A two-electrode system was then fabricated with the optimized electrode that shows a benchmark current density of 10 mA cm-2 at 1.783 V, providing a yield of 70% for dihydroisoquinolines. A robust stability was also shown for this integrated electrochemical system. The understanding of the reconstruction behavior and the achievement of selective dehydrogenation will provide some hints for electrochemical synthesis.

Geriatric nutritional risk index is associated with the occurrence of acute kidney injury in critically ill patients with acute heart failure.

Background: During the acute heart failure (AHF), acute kidney injury (AKI) is highly prevalent in critically ill patients. The occurrence of the latter condition increases the risk of mortality in patients with acute heart failure. The current research on the relationship between nutritional risk and the occurrence of acute kidney injury in patients with acute heart failure is very limited. Methods: This retrospective cohort study utilized data from the Medical Information Mart for Intensive Care IV (MIMIC-IV, version 2.1) database. We included adult patients with AHF who were admitted to the intensive care unit in the study. Results: A total of 1310 critically ill patients with acute heart failure were included. The AUC of geriatric nutritional risk index (GNRI) (0.694) is slightly superior to that of controlling nutritional status (CONUT) (0.656) and prognostic nutritional index (PNI) (0.669). The Log-rank test revealed a higher risk of acute kidney injury in patients with high nutritional risk (p < 0.001). Multivariate COX regression analysis indicated that a high GNRI (adjusted HR 0.62, p < 0.001) was associated with a reduced risk of AKI during hospitalization in AHF patients. The final subgroup analysis demonstrated no significant interaction of GNRI in all subgroups except for diabetes subgroup and ventilation subgroup (P for interaction: 0.057-0.785). Conclusion: Our study findings suggest a correlation between GNRI and the occurrence of acute kidney injury in patients hospitalized with acute heart failure.

Development and characterization of an antibody that recognizes influenza virus N1 neuraminidases.

Influenza A viruses (IAVs) continue to pose a huge threat to public health, and their prevention and treatment remain major international issues. Neuraminidase (NA) is the second most abundant surface glycoprotein on influenza viruses, and antibodies to NA have been shown to be effective against influenza infection. In this study, we generated a monoclonal antibody (mAb), named FNA1, directed toward N1 NAs. FNA1 reacted with H1N1 and H5N1 NA, but failed to react with the NA proteins of H3N2 and H7N9. In vitro, FNA1 displayed potent antiviral activity that mediated both NA inhibition (NI) and blocking of pseudovirus release. Moreover, residues 219, 254, 358, and 388 in the NA protein were critical for FNA1 binding to H1N1 NA. However, further validation is necessary to confirm whether FNA1 mAb is indeed a good inhibitor against NA for application against H1N1 and H5N1 viruses.

Effect of Telitacicept on Circulating Gd-IgA1 and IgA-Containing Immune Complexes in IgA Nephropathy.

Introduction: Telitacicept, a transmembrane activator and cyclophilin ligand interactor (TACI) fusion protein targeting B cell activating factor and a proliferation-inducing ligand (APRIL), has proven efficacy in treating Immunoglobulin A (IgA) nephropathy (IgAN). However, serum biomarkers that could predict the clinical response during the treatment remain unclear. Methods: Plasma samples from 24 participants in the phase 2 clinical trial were collected at baseline and after 4, 12, and 24 weeks; with 8 participants in the placebo group, 9 in the 160 mg group, and 7 in the 240 mg group. We measured the levels of galactose-deficient-IgA1 (Gd-IgA1), IgA-containing immune complexes, C3a, C5a, and sC5b-9. The association between the changes in these markers and proteinuria reduction was analyzed. Results: After 24 weeks of treatment, Gd-IgA1 decreased by 43.9% (95% confidence interval: 29.8%, 55.1%), IgG-IgA immune complex by 31.7% (14.4%, 45.5%), and poly-IgA immune complex by 41.3% (6.5%, 63.1%) in the 160 mg group; Gd-IgA1 decreased by 50.4% (38.6%, 59.9%), IgG-IgA immune complex decreased by 42.7% (29.5%, 53.4%), and poly-IgA immune complex decreased by 67.2% (48.5%,79.1%) in the 240 mg group. There were no significant changes in the circulatory C3a, C5a, or sC5b-9 levels during telitacicept treatment. Decreases in both plasma Gd-IgA1 and IgG-IgA or poly-IgA immune complexes were associated with proteinuria reduction. In turn, IgG-IgA or poly-IgA immune complexes showed a dose-dependent effect, consistent with proteinuria reduction during telitacicept treatment. Conclusion: Telitacicept lowered both circulating Gd-IgA1 and IgA-containing immune complexes, whereas IgA immune complex levels were more consistent with decreased proteinuria.

Dihydroartemisinin-driven TOM70 inhibition leads to mitochondrial destabilization to induce pyroptosis against lung cancer.

Enhancement of malignant cell immunogenicity to relieve immunosuppression of lung cancer microenvironment is essential in lung cancer treatment. In previous study, we have demonstrated that dihydroartemisinin (DHA), a kind of phytopharmaceutical, is effective in inhibiting lung cancer cells and boosting their immunogenicity, while the initial target of DHA's intracellular action is poorly understood. The present in-depth analysis aims to reveal the influence of DHA on the highly expressed TOM70 in the mitochondrial membrane of lung cancer. The affinity of DHA and TOM70 was analyzed by microscale thermophoresis (MST), pronase stability, and thermal stability. The functions and underlying mechanism were investigated using western blots, qRT-PCR, flow cytometry, and rescue experiments. TOM70 inhibition resulted in mtDNA damage and translocation to the cytoplasm from mitochondria due to the disruption of mitochondrial homeostasis. Further ex and in vivo findings also showed that the cGAS/STING/NLRP3 signaling pathway was activated by mtDNA and thereby malignant cells underwent pyroptosis, leading to enhanced immunogenicity of lung cancer cells in the presence of DHA. Nevertheless, DHA-induced mtDNA translocation and cGAS/STING/NLRP3 mobilization were synchronously attenuated when TOM70 was replenished. Finally, DHA was demonstrated to possess potent anti-lung cancer efficacy in vitro and in vivo. Taken together, these data confirm that TOM70 is an important target for DHA to disturb mitochondria homeostasis, which further activates STING and arouses pyroptosis to strengthen immunogenicity against lung cancer thereupon. The present study provides vital clues for phytomedicine-mediated anti-tumor therapy.

The mechanism of microbial sulfate reduction in high concentration sulfate wastewater enhanced by maifanite.

Excessive sulfate levels in water bodies pose a dual threat to the ecological environment and human health. The microbial removal of sulfate encounters challenges, particularly in environments with high sulfate concentrations, where the gradual accumulation of sulfide hampers microbial activity. This study focuses on elucidating the mechanisms underlying the enhancement of microbial sulfate reduction in high-concentration sulfate wastewater through a comparative analysis of maifanite and zeolite biostimulants. The investigation reveals that zeolite primarily facilitates microbial growth by providing attachment sites, while maifanite augments sulfate-reducing bacteria (SRB) activity through the release of active substances such as Mo, Ca, and Cu. The addition of maifanite proves instrumental in enhancing microbial activity, manifesting as increased microbial load and protein production, augmented extracellular polymer generation, accelerated electron transfer, and facilitated microbial growth and biofilm formation. Noteworthy is the observation that the combined application of maifanite and zeolite exhibited a synergistic effect, resulting in a 167 % and 68 % increase in sulfate reduction rate compared to the utilization of maifanite (0.12 d-1) or zeolite (0.19 d-1) in isolation. Within this synergistic context, the relative abundance of Desulfobacteraceae reaches a peak of 15.4 %. The outcomes of this study corroborate the distinct promotion mechanisms of maifanite and zeolite in microbial sulfate reduction, offering novel insights into the application of maifanite in the context of high-concentration sulfate removal.

Association of attenuated leptin signaling pathways with impaired cardiac function under prolonged high-altitude hypoxia.

Cardiovascular function and adipose metabolism were markedly influenced under high altitudes. However, the interplay between adipokines and heart under hypoxia remains to be elucidated. We aim to explore alterations of adipokines and underlying mechanisms in regulating cardiac function under high altitudes. We investigated the cardiopulmonary function and five adipokines in Antarctic expeditioners at Kunlun Station (4,087 m) for 20 days and established rats exposed to hypobaric hypoxia (5,000 m), simulating Kunlun Station. Antarctic expeditioners exhibited elevated heart rate, blood pressure, systemic vascular resistance, and decreased cardiac pumping function. Plasma creatine phosphokinase-MB (CK-MB) and platelet-endothelial cell adhesion molecule-1 (sPecam-1) increased, and leptin, resistin, and lipocalin-2 decreased. Plasma leptin significantly correlated with altered cardiac function indicators. Additionally, hypoxic rats manifested impaired left ventricular systolic and diastolic function, elevated plasma CK-MB and sPecam-1, and decreased plasma leptin. Chronic hypoxia for 14 days led to increased myocyte hypertrophy, fibrosis, apoptosis, and mitochondrial dysfunction, coupled with reduced protein levels of leptin signaling pathways in myocardial tissues. Cardiac transcriptome analysis revealed leptin was associated with downregulated genes involved in rhythm, Na+/K+ transport, and cell skeleton. In conclusion, chronic hypoxia significantly reduced leptin signaling pathways in cardiac tissues along with significant pathological changes, thus highlighting the pivotal role of leptin in regulation of cardiac function under high altitudes.

Potential of polyphenols from Ligustrum robustum (Rxob.) Blume on enhancing the quality of starchy food during frying.

The increasing concerns about health have led to a growing demand for high-quality fried foods. The potential uses of Ligustrum robustum (Rxob.) Blume, a traditional tea in China, as natural additives to enhance the quality of starchy food during frying was studied. Results indicated that L. robustum polyphenols extract (LREs) could improve the quality of fried starchy food, according to the tests of color, moisture content, oil content, texture property, and volatile flavor. The in vitro digestion results demonstrated that LRE reduced the final glucose content from 11.35 ± 0.17 to 10.80 ± 0.70 mmol/L and increased the phenolic content of fried starch foods from 1.23 ± 0.04 to 3.76 ± 0.14 mg/g. The appearance and polarizing microscopy results showed that LRE promoted large starch bulges on the surface of fried starchy foods. Meanwhile, X-ray diffraction results showed that LRE increased the intensity of characteristic diffraction peak of fried starch with a range of 21.8%-28%, and Fourier transform infrared results showed that LRE reduced the damage to short-range order structure of starch caused by the frying process. In addition, LRE increased the aggregation of starch granules according to the SEM observation and decreased the enthalpy of starch gelatinization based on the differential scanning calorimetry results. The present results suggest that LREs have the potential to be utilized as a natural additive for regulating the quality of fried starchy food in food industries. PRACTICAL APPLICATION: The enhancement of L. robustum polyphenols on the quality of starchy food during frying was found, and its mechanisms were also explored. This work indicated that L. robustum might be used as a novel economic natural additive for producing high-quality fried foods.

The Role of Immunotherapy in Triple-Negative Breast Cancer (TNBC).

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype, generally associated with a high risk of recurrence and poor prognosis. Our understanding of the heterogeneity of TNBC has increased over the past decade, and with it a recognition that some TNBCs are immunogenically active. This finding has led to the investigation of immunotherapy-based approaches for treatment of both early and advanced-stage TNBC. In this review, we provide an overview of the biologic rationale for immunotherapy use in TNBC, and review data from seminal trials which have culminated in the approval of immunotherapy for both early and advanced TNBC. Identification of predictive biomarkers to aid in treatment selection, development of novel treatment combinations to combat resistance, and refinement of therapeutic targets enables continued improvement in outcomes with immunotherapy for TNBC.

Melatonin promotes cell cycle progression of neural stem cells subjected to manganese via Nurr1.

Excessive exposure to manganese (Mn) through drinking water and food during pregnancy significantly heightens the likelihood of neurodevelopmental damage in offspring. Multiple studies have indicated that melatonin (Mel) may help to relieve neurodevelopmental disorders caused by Mn, but potential mechanisms underlying this effect require further exploration. Here, we utilized primary neural stem cells (NSCs) as a model to elucidate the molecular mechanism underlying the protective function of Mel on Mn-induced cell proliferation dysfunction and cycle arrest. Our results showed that Mn disrupted the cell cycle in NSCs by suppressing positive regulatory proteins (CDK2, Cyclin A, Cyclin D1, and E2F1) and enhancing negative ones (p27KIP1 and p57KIP2), leading to cell proliferation dysfunction. Mel inhibited the Mn-dependent changes to these proteins and the cell cycle through nuclear receptor-related protein 1 (Nurr1), thus alleviating the proliferation dysfunction. Knockdown of Nurr1 using lentivirus-expressed shRNA in NSCs resulted in a diminished protective effect of Mel. We concluded that Mel mitigated Mn-induced proliferation dysfunction and cycle arrest in NSCs through Nurr1.

A novel tumor mutation-related long non-coding RNA signature for predicting overall survival and immunotherapy response in lung adenocarcinoma.

Background: Immunotherapy has changed the treatment landscape for lung cancer. This study aims to construct a tumor mutation-related model that combines long non-coding RNA (lncRNA) expression levels and tumor mutation levels in tumor genomes to detect the possibilities of the lncRNA signature as an indicator for predicting the prognosis and response to immunotherapy in lung adenocarcinoma (LUAD). Methods: We downloaded the tumor mutation profiles and RNA-seq expression database of LUAD from The Cancer Genome Atlas (TCGA). Differentially expressed lncRNAs were extracted based on the cumulative number of mutations. Cox regression analyses were used to identify the prognostic lncRNA signature, and the prognostic value of the five selected lncRNAs was validated by using survival analysis and the receiver operating characteristic (ROC) curve. We used qPCR to validate the expression of five selected lncRNAs between human lung epithelial and human lung adenocarcinoma cell lines. The ImmuCellAI, immunophenoscore (IPS) scores and Tumor Immune Dysfunction and Exclusion (TIDE) analyses were used to predict the response to immunotherapy for this mutation related lncRNA signature. Results: A total of 162 lncRNAs were detected among the differentially expressed lncRNAs between the Tumor mutational burden (TMB)-high group and the TMB-low group. Then, five lncRNAs (PLAC4, LINC01116, LINC02163, MIR223HG, FAM83A-AS1) were identified as tumor mutation-related candidates for constructing the prognostic prediction model. Kaplan‒Meier curves showed that the overall survival of the low-risk group was significantly better than that of the high-risk group, and the results of the GSE50081 set were consistent. The expression levels of PD1, PD-L1 and CTLA4 in the low-risk group were higher than those in the high-risk group. The IPS scores and TIDE scores of patients in the low-risk group were significantly higher than those in the high-risk group. Conclusion: Our findings demonstrated that the five lncRNAs (PLAC4, LINC01116, LINC02163, MIR223HG, FAM83A-AS1) were identified as candidates for constructing the tumor mutation-related model which may serve as an indicator of tumor mutation levels and have important implications for predicting the response to immunotherapy in LUAD.

Effect of 3D printing technology-assisted TKA on cartilage tissue in rabbit with knee osteoarthritis.

BACKGROUND: Knee osteoarthritis (KOA) is a common chronic degenerative joint disease. 3D printing technology has become one of the important directions of medical development along with individualized precision treatment in orthopedics. OBJECTIVE: To investigate the effect of 3D printing technology-assisted total knee arthroplasty (TKA) on cartilage in rabbits with KOA. METHODS: A rabbit model of KOA was established and treated by TKA or 3D printing-assisted TKA. Four weeks after treatment, radiological evaluation of rabbit knees was performed by X-ray examination, in order to observe the severity of osteoarthritic lesions. Then the knee joints of rabbits were collected for Hematoxylin-eosin, Toluidine blue, and Safranin O-Fast green staining. The expressions of cartilage matrix metabolism-related and apoptosis-related genes were scrutinized by real-time quantitative reverse transcription-polymerase chain reaction, Western blot, and immunohistochemistry. The levels of inflammatory-related factors in the cartilage tissues of rabbits were tested by enzyme-linked immunosorbent assay. RESULTS: In rabbits with KOA, 3D printing technology-assisted TKA alleviated the inflammation and bone remodeling of the knee joint, relieved synovial hyperplasia and inflammatory cell infiltration in the articular cartilage, reduced articular cartilage degradation, suppressed cartilage matrix metabolism, and mitigated the inflammatory response and apoptosis of cartilage cells. CONCLUSION: 3D printing technology-assisted TKA exhibits a good treatment effect in rabbit KOA. This study provides an important basis for the clinical application of 3D printing technology-assisted TKA in KOA treatment.

Super-Ionic Conductor Soft Filler Promotes Li+ Transport in Integrated Cathode-Electrolyte for Solid-State Battery at Room Temperature.

Composite polymer solid electrolytes (CPEs), possessing good rigid flexible, are expected to be used in solid-state lithium-metal batteries. The integration of fillers into polymer matrices emerges as a dominant strategy to improve Li+ transport and form a Li+-conducting electrode-electrolyte interface. However, challenges arise as traditional fillers: 1) inorganic fillers, characterized by high interfacial energy, induce agglomeration; 2) organic fillers, with elevated crystallinity, impede intrinsic ionic conductivity, both severely hindering Li+ migration. Here, a concept of super-ionic conductor soft filler, utilizing a Li+ conductivity nanocellulose (Li-NC) as a model, is introduced which exhibits super-ionic conductivity. Li-NC anchors anions, and enhances Li+ transport speed, and assists in the integration of cathode-electrolyte electrodes for room temperature solid-state batteries. The tough dual-channel Li+ transport electrolyte (TDCT) with Li-NC and polyvinylidene fluoride (PVDF) demonstrates a high Li+ transfer number (0.79) due to the synergistic coordination mechanism in Li+ transport. Integrated electrodes' design enables stable performance in LiNi0.5Co0.2Mn0.3O2|Li cells, with 720 cycles at 0.5 C, and 88.8% capacity retention. Furthermore, the lifespan of Li|TDCT|Li cells over 4000 h and Li-rich Li1.2Ni0.13Co0.13Mn0.54O2|Li cells exhibits excellent performance, proving the practical application potential of soft filler for high energy density solid-state lithium-metal batteries at room temperature.

H2-Promoted Benign Coke Strategy for Dimethyl Ether Carbonylation with Long-Term Stability and High Activity.

Zeolite-catalyzed dimethyl ether (DME) carbonylation provides a novel route to producing methyl acetate (MeOAc). Mordenite (MOR) has drawn significant interest because of its remarkable MeOAc selectivity in DME carbonylation, albeit with limited catalytic stability. Herein, novel MOR-based DME carbonylation catalysts, distinguished by long-term stability and high activity were successfully developed, based on an H2-promoted benign coke strategy. Both the H2 cofeeds and the presence of metal species with hydrogenation capability are demonstrated to be crucial for the regulation of coke depositions. The coke deposits can potentially cover the acid sites in the 12-MR main channels, thereby mitigating the occurrence of undesirable methanol-to-hydrocarbon side reactions. Meanwhile, the elimination of ultralarge coke species under the assistance of H2 and Cu species could ensure smooth mass transfer within the catalyst, contributing to its remarkable catalytic performance. The most highlighted DME carbonylation performance was achieved on coke-mediated CuZn-HMOR with a high MeOAc yield of 0.4-0.5 g·gcat-1·h-1 for over 520 h (over 50× enhancement versus HMOR), exhibiting promising industrial application potential. The current strategy is expected to inspire further research into zeolite-catalyzed reactions, which could be potentially improved by the presence of benign coke.

A Study of the Drift Phenomena of Gate-Functionalized Biosensors and Dual-Gate-Functionalized Biosensors in Human Serum.

In this paper, we study the drift behavior of organic electrochemical transistor (OECT) biosensors in a phosphate-buffered saline (PBS) buffer solution and human serum. Theoretical and experimental methods are illustrated in this paper to understand the origin of the drift phenomenon and the mechanism of ion diffusion in the sensing layer. The drift phenomenon is explained using a first-order kinetic model of ion adsorption into the gate material and shows very good agreement with experimental data on drift in OECTs. We show that the temporal current drift can be largely mitigated using a dual-gate OECT architecture and that dual-gate-based biosensors can increase the accuracy and sensitivity of immuno-biosensors compared to a standard single-gate design. Specific binding can be detected at a relatively low limit of detection, even in human serum.

The role of exogenous hydrogen sulfide in mitigating cadmium toxicity in plants: A comprehensive meta-analysis.

Reducing the accumulation of cadmium (Cd) and mitigating its toxicity are pivotal strategies for addressing Cd pollution's threats to agriculture and human health. Hydrogen sulfide (H2S) serves as a signaling molecule, playing a crucial role in plant stress defense mechanisms. Nevertheless, a comprehensive assessment of the impact of exogenous H2S on plant growth, antioxidant properties, and gene expression under Cd stress remains lacking. In this meta-analysis, we synthesized 575 observations from 27 articles, revealing that exogenous H2S significantly alleviates Cd-induced growth inhibition in plants. Specifically, it enhances root length (by 8.71%), plant height (by 15.67%), fresh weight (by 15.15%), dry weight (by 22.54%), and chlorophyll content (by 27.99%) under Cd stress conditions. H2S boosts antioxidant enzyme activity, particularly catalase (CAT), by 39.51%, thereby reducing Cd-induced reactive oxygen species (ROS) accumulation. Moreover, it impedes Cd translocation from roots to shoots, resulting in a substantial 40.19% reduction in stem Cd content. Additionally, H2S influences gene expression in pathways associated with antioxidant enzymes, metal transport, heavy metal tolerance, H2S biosynthesis, and energy metabolism. However, the efficacy of exogenous H2S in alleviating Cd toxicity varies depending on factors such as plant species, concentration of the H2S donor sodium hydrosulfide (NaHS), application method, and cultivation techniques. Notably, NaHS concentrations exceeding 200 µM may adversely affect plants. Overall, our study underscores the role of exogenous H2S in mitigating Cd toxicity and elucidates its mechanism, providing insights for utilizing H2S to combat Cd pollution in agriculture.

Overexpression of SQUAMOSA promoter binding protein-like 4a (NtSPL4a) alleviates Cd toxicity in Nicotiana tabacum.

Squamosa Promoter Binding Protein-Like (SPL) plays a crucial role in regulating plant development and combating stress, yet its mechanism in regulating resistance to Cd toxicity remains unclear. In this study, we cloned a nuclear-localized transcription factor, NtSPL4a, from the tobacco cultivar TN90. Transient co-expression results showed that miR156 significantly reduced the expression of NtSPL4a by binding to the 3'-UTR of its transcript. We obtained transgenic tobacco overexpressing NtSPL4a (including the 3'-UTR) and NtSPL4aΔ (lacking the 3'-UTR) through Agrobacterium-mediated genetic transformation. Compared to the wild type (WT), overexpression of NtSPL4a/NtSPL4aΔ shortened the flowering time and exhibited a more developed root system. The transgenic tobacco showed significantly reduced Cd content, being 85.1% (OE-NtSPL4a) and 46.7% (OE-NtSPL4aΔ) of WT, respectively. Moreover, the upregulation of NtSPL4a affected the mineral nutrient homeostasis in transgenic tobacco. Additionally, overexpression of NtSPL4a/NtSPL4aΔ effectively alleviated leaf chlorosis and oxidative stress induced by Cd toxicity. One possible reason is that the overexpression of NtSPL4a/NtSPL4aΔ can effectively promote the accumulation of non-enzymatic antioxidants. A comparative transcriptomic analysis was performed between transgenic tobacco and WT to further unravel the global impacts brought by NtSPL4a. The tobacco overexpressing NtSPL4a had 183 differentially expressed genes (77 upregulated, 106 downregulated), while the tobacco overexpressing NtSPL4aΔ had 594 differentially expressed genes (244 upregulated, 350 downregulated) compared to WT. These differentially expressed genes mainly included transcription factors, metal transport proteins, flavonoid biosynthesis pathway genes, and plant stress-related genes. Our study provides new insights into the role of the transcript factor SPL in regulating Cd tolerance.