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The mechanical properties of coal measure rocks and their evaluation significantly impact the process and efficacy of coal measure exploration and development. This study focuses on the Guizhou Longtan Formation coal measure. The mechanical and fracturing characteristics of coal measure rock samples are analyzed via well coring, geophysical logging, and indoor experiments. Additionally, predictive models for rock mechanical parameters are developed, and an evaluation system for the Longtan Formation coal measure rock mass is established. The findings are as follows: (1) Coal measure rocks in Guizhou's Longtan Formation exhibit a relatively low elastic modulus and tensile strength, but a substantial variation in compressive strength. The triaxial compressive strength, elastic modulus, and residual strength increase nonlinearly with increasing confining pressure. As the confining pressure increases, the failure mode of the mudstone and siltstone transitions from primarily splitting failure to shearing failure. (2) Strong correlations are calculated between logging parameters and rock mechanical parameters and are used to construct three regression prediction models, yielding an average prediction accuracy of approximately 85% for rock mechanical properties. (3) Considering the rock mechanical properties, rock mass structure and stratigraphic characteristics, and the occurrence environment related to the characteristics of rock mass affecting coal measure gas development, eight evaluation indices are selected. The analytic hierarchy process-entropy weighting method is used to determine the weights of the comprehensive evaluation indices, and a coal measure rock mass evaluation system is established by utilizing gray clustering analysis. The evaluation results categorize the mudstone group (mudstone and silty mudstone) as Classes III-IV, the fine sandstone group as Classes I and II, and the siltstone group (muddy siltstone and siltstone) as Classes II and III. A comparative analysis with fuzzy comprehensive evaluation results and extenics theory evaluation results demonstrated a high level of consistency. These findings benefit coal measure rock mechanics classification and quantitative research on rock mechanics properties, providing a solid foundation for efficient coal measure gas exploration and development.
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This study conducted a comparison of the effects of non-protein nitrogen with different acid-base properties on feed intake, rumen fermentation, nutrient digestion and antioxidant capacity in fattening Hu sheep. Sixteen fattening male sheep (31.43 ± 2.41 kg) with permanent rumen cannulas were randomly assigned to two dietary treatments: 1% urea and 1.78% ammonium chloride (NH4Cl, AC). A 42 days experimental period was conducted, with 14 days for adaptation and 28 days for treatment. Daily feed intake was recorded and various samples including feed, feces, rumen fluid, and blood were collected at different time points during the final week. The results indicated that the urea group had significantly higher dry matter intake, average daily gain, and gain efficiency in comparison to the AC group (p < 0.01). There was no difference in rumen pH and concentration of ammonia nitrogen between different groups (p > 0.05), but the rumen pH of urea group was higher than that of the AC group at 1 and 3 h after feeding (p < 0.05). The urea group exhibited higher concentrations of total volatile fatty acids (VFA) and individual VFAs compared to the AC group at all-time points (p < 0.01). Compared to the urea group, the intake of all nutrients decreased in the AC group (p < 0.01), but the digestibility of dry matter and organic matter increased significantly (p < 0.01), and the digestibility of CP had an increasing trend (p = 0.06) in the AC group. Additionally, the urea group had lower levels of serum glucagon-like peptide-1, peptide YY, Cl, total protein and globulin than the AC group (p < 0.05). The overall levels of HCO3-, superoxide dismutase, glutathione peroxidase, catalase, albumin/globulin, blood urea nitrogen and total cholesterol in the urea group increased significantly compared to the AC group (p < 0.05). It was concluded that adding urea to the high-concentrate diet resulted in increased rumen pH and improved rumen fermentation and growth performance in fattening sheep compared to NH4Cl addition. Furthermore, urea addition improved sheep's antioxidant capacity and maintained their acid-base balance more effectively as compared to NH4Cl.
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Bacterial nanocellulose (BNC) is an attractive green-synthesized biomaterial for biomedical applications and various other applications. However, effective engineering of BNC production has been limited by our poor knowledge of the related metabolic processes. In contrast to the traditional perception that genome critically determines biosynthesis behaviors, here we discover that the glucose metabolism could also drastically affect the BNC synthesis in Gluconacetobacter hansenii. The transcriptomic profiles of two model BNC-producing strains, G. hansenii ATCC 53582 and ATCC 23769, which have highly similar genomes but drastically different BNC yields, were compared. The results show that their BNC synthesis capacities were highly related to metabolic activities such as ATP synthesis, ion transport protein assembly, and carbohydrate metabolic processes, confirming an important role of metabolism-related transcriptomes in governing the BNC yield. Our findings provide insights into the microbial biosynthesis behaviors from a transcriptome perspective, potentially guiding cellular engineering for biomaterial synthesis.
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Perfilación de la Expresión Génica , Transcriptoma , Transcriptoma/genética , Materiales Biocompatibles , Ingeniería Celular , Transporte IónicoRESUMEN
In the context of carbon neutrality, promoting resource utilization of industrial alkali lignin addressing heavy metal pollution is crucial for China's pollution alleviation and carbon reduction. Microwave pyrolysis produced functionalized biochar from industrial alkali lignin for Ni(II) adsorption. LB400 achieved 343.15 mg g-1 saturated adsorption capacity in 30 min. Pseudo-second-order kinetic and Temkin isotherm models accurately described the adsorption, which was endothermic and spontaneous (ΔGÏ´ < 0, ΔHÏ´ > 0). Quantitative analysis revealed that both dissolved substances and carbon skeleton from biochar contributed to adsorption, with the former predominates (93.76%), including mineral precipitation NiCO3 (Qp) and adsorption of dissolved organic matter (QDOM). Surface complexation (Qc) and ion exchange (Qi) on the carbon skeleton accounted for 6.3%. Higher biochar preparation temperature reduced Ni(II) adsorption by dissolved substances. Overall, biochar which comes from the advantageous disposal of industrial lignin effectively removes Ni(II) contamination, encouraging ecologically sound treatment of heavy metal pollution and sustainable resource utilization.
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Metales Pesados , Contaminantes Químicos del Agua , Lignina , Adsorción , Carbón Orgánico , Carbono , Álcalis , CinéticaRESUMEN
The B3 family genes constitute a pivotal group of transcription factors that assume diverse roles in the growth, development, and response to both biotic and abiotic stresses in plants. Medicago truncatula is a diploid plant with a relatively small genome, adopted as a model species for legumes genetics and functional genomic research. In this study, 173 B3 genes were identified in the M. truncatula genome, and classified into seven subgroups by phylogenetic analysis. Collinearity analysis revealed that 18 MtB3 gene pairs arose from segmented replication events. Analysis of expression patterns disclosed that 61 MtB3s exhibited a spectrum of expression profiles across various tissues and in the response to salt stress, indicating their potential involvement in salt stress signaling response. Among these genes, MtB3-53 exhibited tissue-specific differential expression and demonstrated a rapid response to salt stress induction. Overexpression of MtB3-53 gene in Arabidopsis improves salt stress tolerance by increasing plant biomass and chlorophyll content, while reducing leaf cell membrane damage. Moreover, salt treatment resulted in more up-regulation of AtABF1, AtABI3, AtHKT1, AtKIN1, AtNHX1, and AtRD29A in MtB3-53 transgenic Arabidopsis plants compared to the wild type, providing evidences that MtB3-53 enhances plant salt tolerance not only by modulating ion homeostasis but also by stimulating the production of antioxidants, which leads to the alleviation of cellular damage caused by salt stress. In conclusion, this study provides a fundamental basis for future investigations into the B3 gene family and its capacity to regulate plant responses to environmental stressors.
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Arabidopsis , Medicago truncatula , Medicago truncatula/metabolismo , Filogenia , Arabidopsis/genética , Arabidopsis/metabolismo , Estrés Salino/genética , Tolerancia a la Sal/genética , Estrés Fisiológico/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
Recurrent spontaneous abortion (RSA) is a multifactorial disease that seriously affects womens physical and mental health. With the advent of efficient contraception, the trend for women towards later maternity until their thirties or even forties. Nevertheless, the risk of miscarriage is strongly related to maternal age. We performed a retrospective analysis to evaluate the etiology of RSA through age groups. The results demonstrated that intrauterine adhesions and ovarian dysfunction were responsible for increased miscarriages in older RSA patients. In conclusion, older women will bear a higher risk of miscarriage, mainly due to uterine adhesions or decreased ovarian function.
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Purpose: The abnormal activation of NLRP3 inflammasome is related to the occurrence and development of ulcerative colitis (UC). However, the ideal drug and delivery system remain important factors limiting the targeting of NLRP3 inflammasome in UC therapy. Gene therapy by delivering siRNA is effective in treating various diseases. Therefore, delivering siNLRP3 using an ideal vector for UC treatment is necessary. Materials and Methods: Nanoparticles delivering siNLRP3 were developed based on cationic liposome (CLP/siNLRP3). Their ability to inhibit NLRP3 inflammasome activation was monitored using Western blot (WB) and Enzyme-linked Immunosorbent Assay (ELISA). The ASC oligomerization in LPS-primed peritoneal macrophages (PMs) was detected by WB and immunofluorescence. Moreover, we assessed the role of CLP/siNLRP3 on dextran sodium sulfate (DSS)-induced UC by examining NLRP3 levels, pro-inflammatory cytokines expression, and disease-associated index (DAI). Flow cytometry (FCM) was used to detect the contents of macrophages and T cells. Finally, we assessed the safety of CLP/siNLRP3. Results: The prepared CLP was spherical, with a small particle size (94 nm) and low permeability. The CLP could efficiently protect siNLRP3 from degradation and then deliver siNLRP3 into PMs, inhibiting NLRP3 inflammasome activation. Also, the CLP/siNLRP3 could inhibit the secretion of mature IL-1ß and IL-18 from PMs, thereby achieving a favorable anti-inflammation effect. In vivo, CLP/siNLRP3 could effectively alleviate intestinal injury in UC mice, which was attributed to down-regulating levels of IL-1ß and IL-18, inhibiting infiltration of macrophages and other immune cells, and the polarization of M1 macrophages. Finally, pathological testing of tissue sections and blood biochemical tests showed no significant toxic effects of CLP/siNLRP3. Conclusion: We introduced a prospective approach for the efficient delivery of siRNA in vitro and in vivo with high safety and stability, which was found to have great potential in treating NLRP3-driven diseases in an RNA-silencing manner.
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Colitis Ulcerosa , Interleucina-18 , Animales , Ratones , ARN Interferente Pequeño/genética , Liposomas , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Colitis Ulcerosa/inducido químicamente , Colitis Ulcerosa/terapia , Inflamasomas , CationesRESUMEN
Exploring an efficient and robust electrocatalyst for hydrogen evolution reaction (HER) at high pH and temperature holds the key to the industrial application of alkaline water electrolysis (AWE). Herein, we design an open tunnel structure by dealloying a series of Laves phase intermetallics, i.e., MCo2 and MRu0.25Co1.75 (M = Sc and Zr). The dealloying process can induce a zeolite-like metal framework for ScCo2 and ScRu0.25Co1.75 by stripping Sc metal from the center of a tunnel structure. This structural engineering significantly lowers their overpotentials at a current density of 500 mA/cm2 (η500) ca. 80 mV in 1.0 M KOH. Through a simple process, ScRu0.25Co1.75 can be easily decorated on a carbon cloth substrate and only requires 132 mV to reach 500 mA/cm2. More importantly it can maintain activity over 1000 h in industrial conditions (6.0 M KOH at 333 K), showing its potential for practical industrial applications.
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The steady-state gut microbiome not only promotes the metabolism and absorption of nutrients that are difficult to digest by the host itself, but also participates in systemic metabolism. Once the dynamic balance is disturbed, the gut microbiome may lead to a variety of diseases. Recurrent pregnancy loss (RPL) affects 1-2% of women of reproductive age, and its prevalence has increased in recent years. According to the literature review, the gut microbiome is a new potential driver of the pathophysiology of recurrent abortion, and the gut microbiome has emerged as a new candidate for clinical prevention and treatment of RPL. However, few studies have concentrated on the direct correlation between RPL and the gut microbiome, and the mechanisms by which the gut microbiome influences recurrent miscarriage need further investigation. In this review, the effects of the gut microbiome on RPL were discussed and found to be associated with inflammatory response, the disruption of insulin signaling pathway and the formation of insulin resistance, maintenance of immunological tolerance at the maternal-fetal interface due to the interference with the immune imbalance of Treg/Th17 cells, and obesity.
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Aborto Habitual , Microbioma Gastrointestinal , Aborto Habitual/epidemiología , Humanos , Femenino , EmbarazoRESUMEN
The percolation-degradation process of soluble domestic pollution is very important for the evolution of soil properties and the formation of contaminated sites. The main objective of this study is to investigate the influence of glucose seepage-degradation on the permeability of clay through an indoor percolation test in combination with thermogravimetric measurement with glucose as a representative domestic contaminant soluble sugar. We can conclude that the permeability of clay was significantly impacted by the seepage-degradation of soluble sugar. With a focus on the role of soluble sugars in domestic source pollutants on clay, the formation and evolution of the domestic source contaminated soil site went through three main stages: "generation of domestic source contaminated liquid & formation of S-C zone", "contraction of S-C zone & formation of E-C zone and C zone", and "disappearance of S-C zone & contraction of E-C zone and C zone". The clay permeability decreased, the migration range shrinked, and the pollution level of the clay near the source of the contaminants increased with increasing soluble sugar solution concentration.
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Contaminación Ambiental , Contaminantes del Suelo , Arcilla , Suelo , Glucosa , Azúcares , Contaminantes del Suelo/análisisRESUMEN
BACKGROUND: Elevated serum ferritin levels (SFLs) was previously reported to be related with hepatic histologic severity and advanced liver fibrosis among non-alcoholic fatty liver disease (NAFLD) patients. However, whether NAFLD influences SFLs remains uncertain and needs more clinical evidences. This study explored the differences of SFLs in US adults with or without NAFLD. METHODS: We conducted a cross-sectional study of 3689 participants aged 18-80 years using the National Health and Nutrition Examination Survey (NHANES) 2017-2018 cycle. NAFLD status was confirmed based on controlled attenuation parameter (CAP) values ≥274 dB/m through vibration controlled and transient elastography (VCTE). We performed weighted multivariable logistic regression models to evaluate the associations between NAFLD and SFLs in different age and gender. RESULTS: There was a positive association between NAFLD and SFLs in all three models (model 1:ß = 23.07, 95% CI: 10.32, 35.81; model 2:ß = 23.68, 95% CI: 10.86, 36.50; model 3:ß = 13.86, 95% CI: 0.29, 27.43). After adjusting for the covariates, this positive association persisted in females (ß = 16.22, 95% CI: 2.81, 29.62). Further, relationships between NAFLD and SFLs were significantly different in various age groups. In the subgroup stratified by gender, their associations further differed. In males, the positive association was more prominent in 50-64 age group (ß = 70.89, 95% CI: 25.14, 116.64). In females, this positive association was more prominent in 18-34 age group (ß = 20.72, 95% CI: 7.45, 33.99). However, no correlations between severe steatosis, significant fibrosis, advanced fibrosis, cirrhosis, and SFLs in adults with NAFLD were found. CONCLUSION: This study indicated that US adults suffered with NAFLD had significantly higher SFLs compared with their counterparts in non-NAFLD group. Moreover, the associations between NAFLD and SFLs further differed by age and gender.
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Ferritinas/sangre , Enfermedad del Hígado Graso no Alcohólico/sangre , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Humanos , Cirrosis Hepática/sangre , Cirrosis Hepática/complicaciones , Masculino , Persona de Mediana Edad , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Encuestas Nutricionales , Factores Sexuales , Estados UnidosRESUMEN
Bermudagrass (Cynodon dactylon) is one of the most widely cultivated warm-season turfgrass species around the world. Cold stress has been a key environmental factor that adversely affects the growth, development, and geographical distribution of bermudagrass; however, the underlying mechanism of bermudagrass responsive to cold stress remains largely unexplored. Here, we identified a cold-induced WRKY transcription factor CdWRKY2 from bermudagrass and demonstrated its function in cold stress response. Overexpression of CdWRKY2 enhanced cold tolerance in transgenic Arabidopsis and bermudagrass hairy roots, while knocking down CdWRKY2 expression via virus-induced gene silencing increased cold susceptibility. RNA sequencing showed that overexpression of CdWRKY2 in Arabidopsis activated the expression of genes involved in sucrose synthesis and metabolism, including sucrose synthase 1 (AtSUS1) and sucrose phosphate synthase 2F (AtSPS2F). CdSPS1, the homology gene of AtSPS2F in bermudagrass, was subsequently proven to be the direct target of CdWRKY2 by yeast one-hybrid, electrophoretic mobility shift assay, and transient expression analysis. As expected, overexpression of CdSPS1 conferred cold tolerance in transgenic Arabidopsis plants, whereas silencing CdSPS1 expression enhanced cold sensitivity in bermudagrass. Besides, CdCBF1 whose expression was dramatically up-regulated in CdWRKY2-overexpressing bermudagrass hairy roots but down-regulated in CdWRKY2-silencing bermudagrass both under normal and cold stress conditions was confirmed as another target of CdWRKY2. Collectively, this study reveals that CdWRKY2 is a positive regulator in cold stress by targeting CdSPS1 and CdCBF1 promoters and activating their expression to coordinately mediate sucrose biosynthesis and CBF-signalling pathway, which provides valuable information for breeding cold-resistant bermudagrass through gene manipulation.
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Arabidopsis , Cynodon , Arabidopsis/genética , Frío , Cynodon/genética , Cynodon/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Fitomejoramiento , Plantas Modificadas Genéticamente , Transducción de Señal/genética , Sacarosa/metabolismoRESUMEN
Clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system has been widely used for precise gene editing in plants. However, simultaneous gene editing of multiple homoeoalleles remains challenging, especially in self-incompatible polyploid plants. Here, we simultaneously introduced targeted mutations in all three homoeoalleles of two genes in the self-incompatible allohexaploid tall fescue, using both CRISPR/Cas9 and LbCas12a (LbCpf1) systems. Loss-of-function mutants of FaPDS exhibited albino leaves, while knockout of FaHSP17.9 resulted in impaired heat resistance in T0 generation of tall fescue. Moreover, these mutations were inheritable. Our findings demonstrate the feasibility of generating loss-of-function mutants in T0 generation polyploid perennial grasses using CRISPR/Cas systems.
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Alelos , Edición Génica , Poaceae/genética , Poliploidía , Autoincompatibilidad en las Plantas con Flores/genética , Secuencia de Bases , Sistemas CRISPR-Cas/genética , Respuesta al Choque Térmico , Mutagénesis/genética , Mutación/genéticaRESUMEN
Based on the leakage of the coalbed methane (CBM) drilling engineering practice of Luan mining area in China, the author determines the safe drilling fluid density range for the stable borehole wall based on borehole wall collapse and fracture pressure. Such parameters as the drilling fluid hydraulic parameters (including pump pressure, pump power and displacement, nozzle diameter, bit pressure drop, bit hydraulic horsepower, circulation pressure drop, impact force and jet velocity) and drilling parameters (including weight-on-bit, drilling rotary speed, bit tooth wear) in each borehole section are optimized. Taking the lowest drilling cost as the controlling target, the drilling parameter optimization model is designed and solved by the genetic algorithm. Furthermore, a software named "CBM borehole wall stability parameter design and optimization" characterized by visualization and applicable for drilling formation condition, which can be used to design and optimize the borehole drilling technological parameters, is developed. This program includes such modules as drilling fluid density prediction, drilling technology design, database management, user management and help. The developed software is proven to solve the drilling leakage effectively in the No.67 borehole practice, which can help drilling engineers to optimize CBM drilling technological parameters safely and quickly.
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Metano , Minería , China , Fenómenos Mecánicos , Programas InformáticosRESUMEN
BACKGROUND: As a cool-season grass species, tall fescue (Festuca arundinacea) is challenged by increasing temperatures. Heat acclimation or activation of leaf senescence, are two main strategies when tall fescue is exposed to heat stress (HS). However, lacking a genome sequence, the complexity of hexaploidy nature, and the short read of second-generation sequencing hinder a comprehensive understanding of the mechanism. This study aims to characterize the molecular mechanism of heat adaptation and heat-induced senescence at transcriptional and post-transcriptional levels. RESULTS: Transcriptome of heat-treated (1 h and 72 h) and senescent leaves of tall fescue were generated by combining single-molecular real-time and Illumina sequencing. In total, 4076; 6917, and 11,918 differentially expressed genes (DEGs) were induced by short- and long-term heat stress (HS), and senescence, respectively. Venn and bioinformatics analyses of DEGs showed that short-term HS strongly activated heat shock proteins (Hsps) and heat shock factors (Hsfs), as well as specifically activated FK506-binding proteins (FKBPs), calcium signaling genes, glutathione S-transferase genes, photosynthesis-related genes, and phytohormone signaling genes. By contrast, long-term HS shared most of DEGs with senescence, including the up-regulated chlorophyll catabolic genes, phytohormone synthesis/degradation genes, stress-related genes, and NACs, and the down-regulated photosynthesis-related genes, FKBPs, and catalases. Subsequently, transient overexpression in tobacco showed that FaHsfA2a (up-regulated specifically by short-term HS) reduced cell membrane damages caused by HS, but FaNAC029 and FaNAM-B1 (up-regulated by long-term HS and senescence) increased the damages. Besides, alternative splicing was widely observed in HS and senescence responsive genes, including Hsps, Hsfs, and phytohormone signaling/synthesis genes. CONCLUSIONS: The short-term HS can stimulate gene responses and improve thermotolerance, but long-term HS is a damage and may accelerate leaf senescence. These results contribute to our understanding of the molecular mechanism underlying heat adaptation and heat-induced senescence.
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Festuca/genética , Respuesta al Choque Térmico/genética , Hojas de la Planta/fisiología , Empalme Alternativo , Festuca/fisiología , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , ARN de Planta , Análisis de Secuencia de ARN , Termotolerancia/genética , Factores de Tiempo , Nicotiana/genéticaRESUMEN
Heat stress has been a major environmental factor limiting the growth and development of Pinellia ternata which is an important Chinese traditional medicine. It has been reported that spermidine (SPD) and melatonin (MLT) play pivotal roles in modulating heat stress response (HSR). However, the roles of SPD and MLT in HSR of P. ternata, and the potential mechanism is still unknown. Here, exogenous SPD and MLT treatments alleviated heat-induced damages in P. ternata, which was supported by the increased chlorophyll content, OJIP curve, and relative water content, and the decreased malondialdehyde and electrolyte leakage. Then, RNA sequencing between CK (control) and Heat (1 h of heat treatment) was conducted to analyze how genes were in response to short-term heat stress in P. ternata. A total of 14,243 (7870 up- and 6373 down-regulated) unigenes were differentially expressed after 1 h of heat treatment. Bioinformatics analysis revealed heat-responsive genes mainly included heat shock proteins (HSPs), ribosomal proteins, ROS-scavenging enzymes, genes involved in calcium signaling, hormone signaling transduction, photosynthesis, pathogen resistance, and transcription factors such as heat stress transcription factors (HSFs), NACs, WRKYs, and bZIPs. Among them, PtABI5, PtNAC042, PtZIP17, PtSOD1, PtHSF30, PtHSFB2b, PtERF095, PtWRKY75, PtGST1, PtHSP23.2, PtHSP70, and PtLHC1 were significantly regulated by SPD or MLT treatment with same or different trends under heat stress condition, indicating that exogenous application of MLT and SPD might enhance heat tolerance in P. ternata through regulating these genes but may with different regulatory patterns. These findings contributed to the identification of potential genes involved in short-term HSR and the improved thermotolerance by MLT and SPD in P. ternata, which provided important clues for improving thermotolerance of P. ternata.
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Melatonina/metabolismo , Pinellia/fisiología , Espermidina/metabolismo , Termotolerancia/genética , Clorofila/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Perfilación de la Expresión Génica , Proteínas de Choque Térmico/metabolismo , Respuesta al Choque Térmico/efectos de los fármacos , Respuesta al Choque Térmico/fisiología , Calor , Fotosíntesis/efectos de los fármacos , Pinellia/genética , Pinellia/metabolismo , Análisis de Secuencia de ARN , Termotolerancia/efectos de los fármacos , Transcriptoma/efectos de los fármacosRESUMEN
Leaf senescence is driven by the expression of senescence-associated genes (SAGs). Development-specific genes often undergo DNA demethylation in their promoter and other regions, which regulates gene expression. Whether and how DNA demethylation regulates the expression of SAGs and thus leaf senescence remain elusive. Whole-genome bisulfite sequencing (WGBS) analyses of wild-type (WT) and demeter-like 3 (dml3) Arabidopsis leaves at three developmental stages revealed hypermethylation during leaf senescence in dml3 compared with WT, and 20 556 differentially methylated regions (DMRs) were identified by comparing the methylomes of dml3 and WT in the CG, CHG, and CHH contexts. Furthermore, we identified that 335 DMR-associated genes (DMGs), such as NAC016 and SEN1, are upregulated during leaf senescence, and found an inverse correlation between the DNA methylation levels (especially in the promoter regions) and the transcript abundances of the related SAGs in WT. In contrast, in dml3 the promoters of SAGs were hypermethylated and their transcript levels were remarkably reduced, and leaf senescence was significantly delayed. Collectively, our study unraveled a novel epigenetic regulatory mechanism underlying leaf senescence in which DML3 is expressed at the onset of and during senescence to demethylate promoter, gene body or 3' UTR regions to activate a set of SAGs.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Desmetilación del ADN , ADN Glicosilasas/metabolismo , ADN de Plantas/metabolismo , Hojas de la Planta/metabolismo , Envejecimiento/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Epigénesis Genética , Hojas de la Planta/fisiologíaRESUMEN
Heat stress is found to be a detrimental factor for growth and development of alfalfa (Medicago sativa L.) which is tremendously invaluable forage due to its high feed value and yield potential. Salicylic acid (SA) has been reported to play a pivotal role in the regulation of plants biotic and abiotic stress response. However, the role of exogenous SA in protecting alfalfa from heat-induced damage has rarely been studied. In this study, four-week-old alfalfa seedlings were treated with 0.25 mM or 0.5 mM SA five days prior to high stress treatment (three day), and various growth and physiological traits were measured. The results showed that exogenous SA pretreatment could improve leaf morphology, plant height, biomass, chlorophyll content, and photosynthetic efficiency of alfalfa under heat stress. Meanwhile, SA could alleviate heat-induced membrane damage by reducing electrolyte leakage (EL) and malondialdehyde (MDA) content, and regulate the activities of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD). The results revealed that exogenous SA application enhanced alfalfa heat tolerance by modulating various morphological and physiological characteristics under heat stress, with more prominent effect at lower concentration (0.25 mM). Overall, this study provides fundamental insights into the SA-mediated physiological adaptation of alfalfa plants to heat stress, which could have useful implication in managing other plants which are suffering global warming.
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Respuesta al Choque Térmico/efectos de los fármacos , Medicago sativa/efectos de los fármacos , Ácido Salicílico/farmacología , Antioxidantes/metabolismo , Catalasa/metabolismo , Clorofila/metabolismo , Malondialdehído/metabolismo , Medicago sativa/crecimiento & desarrollo , Medicago sativa/metabolismo , Peroxidasa/metabolismo , Fotosíntesis/efectos de los fármacos , Superóxido Dismutasa/metabolismoRESUMEN
Self-sustaining smoldering combustion is a promising technology for treating sewage sludge from wastewater treatment plants because of its low energy inputs. Proper use or disposal of the resulting ashes requires thorough characterization of their properties, including the content of total organic carbon (TOC). Here, we develop a two-step method for quantifying TOC in the raw ashes from sewage sludge smoldering combustion. The first step is to thermally treat the raw ashes at 500 °C in N2 for 1 h, followed by ultimate analysis of both the raw ashes and the thermally treated ashes. This enables the quantification of carbon released during thermal treatment. The second step is nonisothermal thermogravimetric analysis (TGA) of the thermally treated ashes, in which the samples are heated to 900 °C at 10 °C/min in air. The weight losses at 310-500 °C are confirmed to be caused by organic carbon oxidation, allowing us to determine the contents of carbon retained in the thermally treated ashes. The sums of these two portions of carbon represent the contents of TOC in the raw ashes, which are â¼0.85-6.52 wt % (dry basis), depending on their locations and particle sizes. The two-step (thermal treatment-TGA) method is validated via a method that includes acid washing of the thermally treated ashes, ultimate analysis of the acid-washed ashes, and TOC analysis of the leachates. The two-step method is simple and accurate and, importantly, provides thorough information on the thermal behavior of the raw and thermally treated ashes.
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Leaf senescence induced by prolonged light deficiency is inevitable whenever turfgrass is cultivated in forests, and this negatively influences the survival and aesthetic quality of the turfgrass. However, the mechanism underlying dark-induced senescence in turfgrass remained obscure. In this study, RNA sequencing was performed to analyze how genes were regulated in response to dark-induced leaf senescence in bermudagrass. A total of 159,207 unigenes were obtained with a mean length of 948 bp. The differential expression analysis showed that a total of 59,062 genes, including 52,382 up-regulated genes and 6680 down-regulated genes were found to be differentially expressed between control leaves and senescent leaves induced by darkness. Subsequent bioinformatics analysis showed that these differentially expressed genes (DEGs) were mainly related to plant hormone (ethylene, abscisic acid, jasmonic acid, auxin, cytokinin, gibberellin, and brassinosteroid) signal transduction, N-glycan biosynthesis, and protein processing in the endoplasmic reticulum. In addition, transcription factors, such as WRKY, NAC, HSF, and bHLH families were also responsive to dark-induced leaf senescence in bermudagrass. Finally, qRT-PCR analysis of six randomly selected DEGs validated the accuracy of sequencing results. Taken together, our results provide basic information of how genes respond to darkness, and contribute to the understanding of comprehensive mechanisms of dark-induced leaf senescence in turfgrass.