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1.
Artigo em Inglês | MEDLINE | ID: mdl-38896515

RESUMO

Cooperative multiagent reinforcement learning (MARL) has attracted significant attention and has the potential for many real-world applications. Previous arts mainly focus on facilitating the coordination ability from different aspects (e.g., nonstationarity and credit assignment) in single-task or multitask scenarios, ignoring the stream of tasks that appear in a continual manner. This ignorance makes the continual coordination an unexplored territory, neither in problem formulation nor efficient algorithms designed. Toward tackling the mentioned issue, this article proposes an approach, multiagent continual coordination via progressive task contextualization (MACPro). The key point lies in obtaining a factorized policy, using shared feature extraction layers but separated independent task heads, each specializing in a specific class of tasks. The task heads can be progressively expanded based on the learned task contextualization. Moreover, to cater to the popular centralized training with decentralized execution (CTDE) paradigm in MARL, each agent learns to predict and adopt the most relevant policy head based on local information in a decentralized manner. We show in multiple multiagent benchmarks that existing continual learning methods fail, while MACPro is able to achieve close-to-optimal performance. More results also disclose the effectiveness of MACPro from multiple aspects, such as high generalization ability.

2.
Biochem Pharmacol ; 223: 116194, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38583812

RESUMO

Glutathione peroxidase 4 (GPX4) is a promising anticancer therapeutic target; however, the application of GPX4 inhibitors (GPX4i) is limited owing to intrinsic or acquired drug resistance. Hence, understanding the mechanisms underlying drug resistance and discovering molecules that can overcome drug resistance are crucial. Herein, we demonstrated that GPX4i killed bladder cancer cells by inducing lipid reactive oxygen species-mediated ferroptosis and apoptosis, and cisplatin-resistant bladder cancer cells were also resistant to GPX4i, representing a higher half-maximal inhibitory concentration value than that of parent bladder cancer cells. In addition, thioredoxin reductase 1 (TrxR1) overexpression was responsible for GPX4i resistance in cisplatin-resistant bladder cancer cells, and inhibiting TrxR1 restored the sensitivity of these cells to GPX4i. In vitro and in vivo studies revealed that Jolkinolide B (JB), a natural diterpenoid and previously identified as a TrxR1 inhibitor, potentiated the antiproliferative efficacy of GPX4i (RSL3 and ML162) against cisplatin-resistant bladder cancer cells. Furthermore, GPX4 knockdown and inhibition could augment JB-induced paraptosis and apoptosis. Our results suggest that inhibiting TrxR1 can effectively improve GPX4 inhibition-based anticancer therapy. A combination of JB and GPX4i, which is well-tolerated and has several anticancer mechanisms, may serve as a promising therapy for treating bladder cancer.


Assuntos
Compostos de Anilina , Diterpenos , Tiofenos , Neoplasias da Bexiga Urinária , Humanos , Cisplatino/farmacologia , Tiorredoxina Redutase 1 , Linhagem Celular Tumoral , Neoplasias da Bexiga Urinária/tratamento farmacológico
3.
Plants (Basel) ; 13(5)2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38475413

RESUMO

Switchgrass is an important bioenergy crop valued for its biomass yield and abiotic tolerance. Alkali stress is a major abiotic stress that significantly impedes plant growth and yield due to high salinity and pH; however, the response mechanism of switchgrass to alkali stress remains limited. Here, we characterized PvARL1, an ARF-like gene, which was up-regulated in both the shoot and root tissues under alkali stress conditions. Overexpression of PvARL1 not only improved alkali tolerance but also promoted biomass yield with more tiller and higher plant height in switchgrass. Moreover, PvARL1 overexpression lines displayed higher capacities in the maintenance of water content and photosynthetic stability compared with the controls under alkali treatments. A significant reduction in the ratio of electrolyte leakage, MDA content, and reactive oxygen species (ROS) showed that PvARL1 plays a positive role in protecting cell membrane integrity. In addition, PvARL1 also negatively affected the K+ efflux or uptake in roots to alleviate ion toxicity under alkali treatments. Overall, our results suggest that PvARL1 functions as a positive regulator in plant growth as well as in the plant response to alkali stress, which could be used to improve switchgrass biomass yield and alkali tolerance genetically.

4.
BMC Musculoskelet Disord ; 25(1): 187, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38424521

RESUMO

BACKGROUND: Osteoporotic fractures are a growing problem in an aging society. The association between body mass index (BMI) and osteoporotic fractures varies by fracture site and ethnicity. Limited knowledge exists regarding this association in native Chinese, particularly utilizing local databases as reference sources. OBJECTIVE: To investigate the association between BMI and osteoporotic fractures at different sites in Chinese women. METHODS: Three thousand ninety-eight female patients with radiographic fractures and 3098 age- and sex-matched healthy controls without fractures were included in the study. Both of them underwent assessment using dual-energy X-ray absorptiometry (DXA), with BMD measurements calculated using our own BMD reference database. Participants were classified into underweight (BMI < 18.5 kg/m2), normal weight (18.5 ≤ BMI < 24.0 kg/m2), overweight (24 ≤ BMI < 28 kg/m2) and obese (BMI ≥ 28 kg/m2) according to the Chinese BMI classification standard. RESULTS: There were 2296 (74.1%) vertebral fractures, 374 (12.1%) femoral neck fractures, and 428 (13.8%) other types of fractures in the case group. Bone mineral density (BMD) was almost lower in the fracture groups compared to the control groups (p = 0.048 to < 0.001). Compared with normal weight, underweight had a protective effect on total [odds ratio (OR) = 0.61; 95% confidence interval (CI), 0.49 -0.75; P< 0.001], and lumbar fractures (OR = 0.52; 95% CI, 0.41 - 0.67; P < 0.001), while obesity was associated with an increased risk for total (OR = 2.26; 95% CI, 1.85 - 2.76; P < 0.001), lumbar (OR = 2.17; 95% CI, 1.72 - 2.73; P < 0.001), and femoral neck fractures (OR = 4.08; 95% CI, 2.18 - 7.63; P < 0.001). Non-linear associations were observed between BMI and fractures: A J-curve for total, lumbar, and femoral neck fractures, and no statistical change for other types of fractures. Underweight was found to be a risk factor for other types of fracturess after adjusting for BMD (OR = 2.29; 95% CI, 1.09 - 4.80; P < 0.001). Osteoporosis and osteopenia were identified as risk factors for almost all sites of fracture when compared to normal bone mass. CONCLUSIONS: Underweight has a protective effect on total and lumbar spine fractures in Chinese women, while obesity poses a risk factor for total, lumbar, and femoral neck fractures. The effect of BMI on fractures may be mainly mediated by BMD.


Assuntos
Fraturas do Colo Femoral , Fraturas por Osteoporose , Fraturas da Coluna Vertebral , Humanos , Feminino , Fraturas por Osteoporose/diagnóstico por imagem , Fraturas por Osteoporose/epidemiologia , Fraturas por Osteoporose/complicações , Índice de Massa Corporal , Estudos Retrospectivos , Magreza/complicações , Magreza/epidemiologia , Densidade Óssea , Absorciometria de Fóton , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fraturas da Coluna Vertebral/epidemiologia , Fraturas da Coluna Vertebral/complicações , Fraturas do Colo Femoral/diagnóstico por imagem , Fraturas do Colo Femoral/epidemiologia , Fraturas do Colo Femoral/complicações , Obesidade/complicações , Obesidade/epidemiologia , Estudos de Casos e Controles , Vértebras Lombares/diagnóstico por imagem , China/epidemiologia
5.
Plant Sci ; 339: 111930, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38007196

RESUMO

Switchgrass (Panicum virgatum L.) plays a pivotal role as a bioenergy feedstock in the production of cellulosic ethanol and contributes significantly to enhancing ecological grasslands and soil quality. The utilization of non-coding RNAs (ncRNAs) has gained momentum in deciphering the intricate genetic responses to abiotic stress in various plant species. Nevertheless, the current research landscape lacks a comprehensive exploration of the responses of diverse ncRNAs, including long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs), to drought stress in switchgrass. In this study, we employed whole transcriptome sequencing to comprehensively characterize the expression profiles of both mRNA and ncRNAs during episodes of drought stress in switchgrass. Our analysis identified a total of 12,511 mRNAs, 59 miRNAs, 38 circRNAs, and 368 lncRNAs that exhibited significant differential expression between normal and drought-treated switchgrass leaves. Notably, the majority of up-regulated mRNAs displayed pronounced enrichment within the starch and sucrose metabolism pathway, as validated through KEGG analysis. Co-expression analysis illuminated that differentially expressed (DE) lncRNAs conceivably regulated 1308 protein-coding genes in trans and 7110 protein-coding genes in cis. Furthermore, both cis- and trans-target mRNAs of DE lncRNAs exhibited enrichment in four common KEGG pathways. The intricate interplay between lncRNAs and circRNAs with miRNAs via miRNA response elements was explored within the competitive endogenous RNA (ceRNA) network framework. As a result, we constructed elaborate regulatory networks, including lncRNA-novel_miRNA480-mRNA, lncRNA-novel_miRNA304-mRNA, lncRNA/circRNA-novel_miRNA122-PvSS4, and lncRNA/circRNA-novel_miRNA14-PvSS4, and subsequently validated the functionality of the target gene, starch synthase 4 (PvSS4). Furthermore, through the overexpression of PvSS4, we ascertained its capacity to enhance drought tolerance in yeast. However, it is noteworthy that PvSS4 did not exhibit any discernible impact under salt stress conditions. These findings, as presented herein, not only contribute substantively to our understanding of ceRNA networks but also offer a basis for further investigations into their potential functions in response to drought stress in switchgrass.


Assuntos
MicroRNAs , Panicum , RNA Longo não Codificante , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Circular/genética , RNA Circular/metabolismo , Panicum/genética , Panicum/metabolismo , RNA Longo não Codificante/genética , Secas , Perfilação da Expressão Gênica , MicroRNAs/genética , MicroRNAs/metabolismo , Redes Reguladoras de Genes
6.
Mol Cell Endocrinol ; 581: 112113, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37989409

RESUMO

Although disorders of primary cilia (PCs) were first reported in human papillary thyroid cancer (PTC) tissues in 1987, their precise role in PTC remains unclear. PCs sense the thyroid follicle colloid environment and act as a cell signaling hub. The present study investigated whether PCs are needed for BRAFV600E-driven PTC. We assessed whether BRAFV600E protein expression correlates with papillary histological architecture and clinicopathological features of PTC. We found that expression of ciliary intraflagellar transport 88 (IFT88) and PC formation were reduced in BRAFV600E-driven PTCs and that loss of cilia may be associated with lymph node metastasis. In PTC cells, the BRAFV600E mutation maintained the aggressiveness of PTC, which was partially related to loss of PCs. Our work confirms that BRAFV600E mutation-driven PC downregulation contributes to maintaining the aggressiveness of PTCs and that manipulating PC can potentially reduce the adverse incidence of PTC in a range of conditions.


Assuntos
Carcinoma Papilar , Neoplasias da Glândula Tireoide , Humanos , Câncer Papilífero da Tireoide/genética , Neoplasias da Glândula Tireoide/patologia , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo , Cílios/metabolismo , Regulação para Baixo/genética , Carcinoma Papilar/genética , Carcinoma Papilar/patologia , Mutação/genética
7.
Org Lett ; 25(28): 5383-5388, 2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37418313

RESUMO

A regioselective electrochemical C-H amination method to synthesize N2-substituted 1,2,3-triazole using easily accessible ethers has been developed. Various substituents, including heterocycles, have a good tolerance, and 24 examples were obtained in moderate to good yields. Control experiments and DFT calculation investigations demonstrate that the electrochemical synthesis undergoes a N-tosyl 1,2,3-triazole radical cation process promoted by the single-electron transfer of the lone pair electrons of the aromatic N-heterocycle, and the desulfonation is responsible for the high N2-regioselectivity.

8.
Plant Cell Rep ; 42(4): 735-748, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36806743

RESUMO

KEY MESSAGE: PvLBD12 enhanced the salt tolerance by increasing proline accumulation, improving K+ accumulation, and decreasing reactive oxygen species level in switchgrass. Abiotic stresses are the serious factors which limit plant development and productivity and restrict the agricultural economy. It is important, therefore, to understand the mechanism of abiotic tolerance in plants. Lateral organ boundaries domain (LBD) proteins as plant-specific transcription factors play important function in plant lateral organ development, plant regeneration, and abiotic stress. In our study, we identify 69 LBD members from switchgrass genome-wide sequences and classify them based on their homology with LBD proteins in Arabidopsis. RT-qPCR showed that PvLBD genes had different expression patterns under abiotic stress conditions, indicating that they play important roles in various stress. PvLBD12 was selected as a candidate gene for further functional analysis because it had the highest expression level under salt stress. Overexpression of PvLBD12 enhanced salt tolerance by altering a wide range of physiological responses (like increased proline accumulation, reduced malondialdehyde production, improved K+ accumulation, and reduced Na+ absorption) in switchgrass. Some stress response genes such as proline biosynthesis gene PvP5CS1, vacuolar Na+(K+)/H+ antiporter gene PvNHX1, two key ROS-scavenging enzyme genes PvCAT and PvSOD were all upregulated in PvLBD12 overexpression lines. Taken together, PvLBD12 plays a pivotal role in response to salt stress by increasing proline accumulation, improving K+ accumulation, reducing Na+ absorption, and decreasing reactive oxygen species level. It will be better to understand the potential biological functions of LBD genes in other plants.


Assuntos
Arabidopsis , Panicum , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Panicum/genética , Panicum/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Tolerância ao Sal/genética , Espécies Reativas de Oxigênio/metabolismo , Arabidopsis/metabolismo , Prolina/metabolismo , Estresse Fisiológico/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
9.
Comput Intell Neurosci ; 2022: 7592258, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35875772

RESUMO

As a new generative model, the generative adversarial network (GAN) has great potential in the accuracy and efficiency of generating pseudoreal data. Nowadays, bearing fault diagnosis based on machine learning usually needs sufficient data. If enough near-real data can be generated in the case of insufficient samples in the actual operating condition, the effect of fault diagnosis will be greatly improved. In this study, a new rolling bearing data generation method based on the generative adversarial network (GAN) is proposed, which can be trained adversarially and jointly via a learned embedding, and applied to solve fault diagnosis problems with insufficient data. By analyzing the time-domain characteristics of rolling bearing life cycle monitoring data in actual working conditions, the operation data are divided into three periods, and the construction and training of the generative adversarial network model are carried out. Data generated by adversarial are compared with the real data in the time domain and frequency domain, respectively, and the similarity between the generated data and the real data is verified.


Assuntos
Aprendizado de Máquina
10.
Cardiovasc Diabetol ; 21(1): 74, 2022 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-35568946

RESUMO

Cardiovascular diseases (CVDs) are the main cause of death among patients with type 2 diabetes mellitus (T2DM), particularly in low- and middle-income countries. To effectively prevent the development of CVDs in T2DM, considerable effort has been made to explore novel preventive approaches, individualized glycemic control and cardiovascular risk management (strict blood pressure and lipid control), together with recently developed glucose-lowering agents and lipid-lowering drugs. This review mainly addresses the important issues affecting the choice of antidiabetic agents and lipid, blood pressure and antiplatelet treatments considering the cardiovascular status of the patient. Finally, we also discuss the changes in therapy principles underlying CVDs in T2DM.


Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Glicemia , Pressão Sanguínea , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Humanos , Hipoglicemiantes/efeitos adversos , Lipídeos
11.
BMC Plant Biol ; 22(1): 163, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35365083

RESUMO

BACKGROUND: The rhizome of Polygonatum kingianum Coll. et Hemsl (P. kingianum) is a crucial traditional Chinese medicine, but severe bud dormancy occurs during early rhizome development. Low temperature is a positive factor affecting dormancy release, whereas the variation in carbohydrates during dormancy release has not been investigated systematically. Therefore, the sugar content, related metabolic pathways and gene co-expression were analysed to elucidate the regulatory mechanism of carbohydrates during dormancy release in the P. kingianum rhizome bud. RESULTS: During dormancy transition, starch and sucrose (Suc) exhibited opposing trends in the P. kingianum rhizome bud, representing a critical indicator of dormancy release. Galactose (Gal) and raffinose (Raf) were increased in content and synthesis. Glucose (Glc), cellulose (Cel), mannose (Man), arabinose (Ara), rhamnose (Rha) and stachyose (Sta) showed various changes, indicating their different roles in breaking rhizome bud dormancy in P. kingianum. At the beginning of dormancy release, Glc metabolism may be dominated by anaerobic oxidation (glycolysis followed by ethanol fermentation). After entering the S3 stage, the tricarboxylic acid cycle (TCA) and pentose phosphate pathway (PPP) were may be more active possibly. In the gene co-expression network comprising carbohydrates and hormones, HYD1 was identified as a hub gene, and numerous interactions centred on STS/SUS were also observed, suggesting the essential role of brassinosteroids (BRs), Raf and Suc in the regulatory network. CONCLUSION: We revealed cold-responsive genes related to carbohydrate metabolism, suggesting regulatory mechanisms of sugar during dormancy release in the P. kingianum rhizome bud. Additionally, gene co-expression analysis revealed possible interactions between sugar and hormone signalling, providing new insight into the dormancy release mechanism in P. kingianum rhizome buds.


Assuntos
Polygonatum , Regulação da Expressão Gênica de Plantas , Humanos , Dormência de Plantas/genética , Proteínas de Plantas/genética , Polygonatum/genética , Polygonatum/metabolismo , Rizoma/metabolismo , Açúcares
12.
Org Lett ; 24(1): 132-136, 2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-34928620

RESUMO

We developed a highly regioselective base-induced synthesis of N2-substituted 1,2,3-triazoles from N-sulfonyl-1,2,3-triazoles and alkyl bromides/alkyl iodides at room temperature. We propose an SN2-like mechanistic pathway to explain the high N2-regioselectivity. The protocol features a broad substrate scope and generates products in good to excellent yields (72-90%).

13.
ISA Trans ; 118: 159-173, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33642029

RESUMO

In this paper, the Bayesian analysis is introduced for the performance prognostics of the marine diesel engine to address the uncertainty of inferences and results by using probability distributions. Two Bayesian models are presented: the Bayesian neural networks model is used to implement health monitoring whilst the Bayesian logistic regression model quantifies the run-to-failure process of the marine diesel engine. The Variational Inference and the Markov Chain Monte Carlo algorithms learn and infer these two models' parameters, respectively. Additionally, by analyzing characteristics of the marine diesel engine, the instantaneous angular speed signals are selected as the condition monitoring data, which can be used to indirectly predict the indicated mean effective pressure and further assess the performance of the marine engine. To verify the superiority of the proposed framework based on the Bayesian models and indirect estimation, operational datasets from a real engine under normal and fault conditions are acquired. The proposed framework and other conventional methods are adopted to analyze the attained data. The results demonstrate that the proposed approach is superior to the other methods and has the potential to be applied as an on-line condition monitoring tool for the performance prognostics of the marine diesel engine.

14.
Plant Cell Rep ; 39(12): 1623-1638, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32885306

RESUMO

KEY MESSAGE: PvArf regulate proline biosynthesis by physically interacting with PvP5CS1 to improve salt tolerance in switchgrass. The genetic factors that contribute to stress resiliency are yet to be determined. Here, we identified three ADP-ribosylation factors, PvArf1, PvArf-B1C, and PvArf-related, which contribute to salinity tolerance in transgenic switchgrass (Panicum virgatum L.). Switchgrass overexpressing each of these genes produced approximately twofold more biomass than wild type (WT) under normal growth conditions. Transgenic plants accumulated modestly higher levels of proline under normal conditions, but this level was significantly increased under salt stress providing better protection to transgenic plants compared to WT. We found that PvArf genes induce proline biosynthesis genes under salt stress to positively regulate proline accumulation, and further demonstrated that PvArf physically interact with PvP5CS1. Moreover, the transcript levels of two key ROS-scavenging enzyme genes were significantly increased in the transgenic plants compared to WT, leading to reduced H2O2 accumulation under salt stress conditions. PvArf genes also protect cells against stress-induced changes in Na+ and K+ ion concentrations. Our findings uncover that ADP-ribosylation factors are key determinants of biomass yield in switchgrass, and play pivotal roles in salinity tolerance by regulating genes involved in proline biosynthesis.


Assuntos
Fatores de Ribosilação do ADP/genética , Panicum/fisiologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/fisiologia , Tolerância ao Sal/genética , Fatores de Ribosilação do ADP/metabolismo , Biomassa , Regulação da Expressão Gênica de Plantas , Homeostase/genética , Peróxido de Hidrogênio/metabolismo , Estresse Oxidativo , Panicum/genética , Proteínas de Plantas/metabolismo , Potássio/metabolismo , Prolina/genética , Prolina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Salinidade , Tolerância ao Sal/fisiologia , Plantas Tolerantes a Sal/genética , Plantas Tolerantes a Sal/fisiologia , Sódio/metabolismo
15.
Phys Rev Lett ; 124(25): 251801, 2020 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-32639772

RESUMO

We present a simple mechanism for generating a Higgs quartic in composite Higgs models without a corresponding quadratic term. This quartic term will originate from a Higgs dependent kinetic mixing between additional fermionic states. The mechanism can be naturally embedded to models with maximal symmetry as well as twin Higgs models. The resulting twin Higgs models will have a fully natural realistic Higgs potential, where the quartic mechanism will serve as the only source for the Z_{2} breaking, while the top and gauge sectors can remain exactly Z_{2} invariant.

16.
Front Plant Sci ; 11: 489, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32411162

RESUMO

Melatonin (N-acetyl-5-methoxytryptamine) is a pleiotropic signaling molecule that plays important roles in plant growth, development and stress responses. Alfalfa (Medicago sativa L.) is an important and widely cultivated leguminous forage crop with high biomass yield and rich nutritional value. The effects of exogenous melatonin content regulation on alfalfa stress tolerance have been investigated in recent years. Here, we isolated and introduced the MsASMT1 (N-acetylserotonin methyltransferase) gene into alfalfa, which significantly improved the endogenous melatonin content. Compared with wild-type (WT) plants, MsASMT1 overexpression (OE-MsASMT1) plants exhibited a series of phenotypic changes, including vigorous growth, increased plant height, enlarged leaves and robust stems with increased cell sizes, cell numbers and vascular bundles, as well as more branches. We also found that the flavonoid content and lignin composition of syringyl to guaiacyl ratio (S/G) were decreased and the cellulose content was increased in OE-MsASMT1 transgenic alfalfa. Further transcriptomic and metabolomic exploration revealed that a large group of genes in phenylalanine pathway related to flavonoids and lignin biosynthesis were significantly altered, accompanied by significantly reduced concentrations of the glycosides of quercetin, kaempferol, formononetin and biochanin in OE-MsASMT1 transgenic alfalfa. Our study first uncovers the effects of endogenous melatonin on alfalfa growth and metabolism. This report provides insights into the regulation effects of melatonin on plant growth and phenylalanine metabolism, especially flavonoids and lignin biosynthesis.

17.
Front Plant Sci ; 11: 46, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32117384

RESUMO

Understanding the regulation of proline metabolism necessitates the suppression of two Δ1-pyrroline-5-carboxylate synthetase enzyme (P5CS) genes performed in switchgrass (Panicum virgatum L.). The results reveal that overexpressing PvP5CS1 and PvP5CS2 increased salt tolerance. Additionally, transcript levels of spermidine (Spd) and spermine (Spm) synthesis and metabolism related genes were upregulated in PvP5CS OE-transgenic plants and downregulated in the PvP5CS RNAi transformants. According to salt stress assay and the measurement of transcript levels of Polyamines (PAs) metabolism-related genes, P5CS enzyme may not only be the key regulator of proline biosynthesis in switchgrass, but it may also indirectly affect the entire subset of pathway for ornithine to proline or to putrescine (Put). Furthermore, application of proline prompted expression levels of Spd and Spm synthesis and metabolism-related genes in both PvP5CS-RNAi and WT plants, but transcript levels were even lower in PvP5CS-RNAi compared to WT plants under salt stress condition. These results suggested that exogenous proline could accelerate polyamines metabolisms under salt stress. Nevertheless, the enzymes involved in this process and the potential functions remain poorly understood. Thus, the aim of this study is to reveal how proline functions with PAs metabolism under salt stress in switchgrass.

18.
Sci Adv ; 6(6): eaax7727, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32076640

RESUMO

Ocean circulation redistributes Earth's energy and water masses and influences global climate. Under historical greenhouse warming, regional ocean currents show diverse tendencies, but whether there is an emerging trend of the global mean ocean circulation system is not yet clear. Here, we show a statistically significant increasing trend in the globally integrated oceanic kinetic energy since the early 1990s, indicating a substantial acceleration of global mean ocean circulation. The increasing trend in kinetic energy is particularly prominent in the global tropical oceans, reaching depths of thousands of meters. The deep-reaching acceleration of the ocean circulation is mainly induced by a planetary intensification of surface winds since the early 1990s. Although possibly influenced by wind changes associated with the onset of a negative Pacific decadal oscillation since the late 1990s, the recent acceleration is far larger than that associated with natural variability, suggesting that it is principally part of a long-term trend.

19.
Sci Rep ; 9(1): 20117, 2019 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-31882839

RESUMO

Transgenic switchgrass overexpressing Lolium perenne L. delta1-pyrroline 5-carboxylate synthase (LpP5CS) in group I (TG4 and TG6 line) and group II (TG1 and TG2 line) had significant P5CS and ProDH enzyme activities, with group I plants (TG4 and TG6) having higher P5CS and lower ProDH enzyme activity, while group II plants had higher ProDH and lower P5CS enzyme activity. We found group II transgenic plants showed stunted growth, and the changed proline content in overexpressing transgenic plants may influence the growth and development in switchgrass. RNA-seq analysis showed that KEGG enrichment included phenylpropanoid biosynthesis pathway among group I, group II and WT plants, and the expression levels of genes related to lignin biosynthesis were significantly up-regulated in group II. We also found that lignin content in group II transgenic plants was higher than that in group I and WT plants, suggesting that increased lignin content may suppress switchgrass growth and development. This study uncover that proline can appropriately reduce lignin biosynthesis to improve switchgrass growth and development. Therefore, appropriate reduction in lignin content and increase in biomass are important for bioenergy crop to lower processing costs for biomass fermentation-derived fuels.


Assuntos
Lignina/biossíntese , Panicum/crescimento & desenvolvimento , Panicum/metabolismo , Desenvolvimento Vegetal , Prolina/metabolismo , Regulação da Expressão Gênica de Plantas , Redes e Vias Metabólicas , NADP/genética , NADP/metabolismo , Panicum/genética , Fenótipo , Desenvolvimento Vegetal/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas
20.
Funct Plant Biol ; 47(1): 38-49, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-31578165

RESUMO

Understanding and enhancing switchgrass (Panicum virgatum L.) photosynthesis will help to improve yield and quality for bio-industrial applications on cellulosic biofuel production. In the present study, leaf anatomical traits and physiological characteristics related to photosynthetic capacity of both lowland and upland switchgrass were recorded from four varieties across the vegetative, elongation and reproductive growth stages. Compared with the upland varieties, the lowland switchgrass showed 37-59, 22-64 and 27-73% higher performance on height, stem and leaf over all three growth stages. Leaf anatomical traits indicated that the leaves of lowland varieties provided more space for carbon assimilation and transportation caused by enhanced cell proliferation with more bundles sheath cells and larger contact areas between the bundle sheath and mesophyll cells (CAMB), which lead to the 32-72% higher photosynthetic capacity found in the lowland varieties during vegetative and elongation growth. However, photosynthetic capacity became 22-51% higher in the upland varieties during the reproductive stage, which is attributed to more photosynthetic pigment. In conclusion, lowland varieties gain a photosynthetic advantage with enhanced bundle sheath cell proliferation, while the upland varieties preserved more photosynthetic pigments. Our study provides new insights for improving the yield in crops by enhancing photosynthesis with anatomical and physiological strategies.


Assuntos
Panicum , Fenótipo , Fotossíntese , Folhas de Planta
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