RESUMEN
Over the past few decades, significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant. However, dense planting triggers shade avoidance responses (SARs) that optimize light absorption but impair plant vigor and performance, limiting yield improvement through increasing plant density. In this study, we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B (phyB1/B2), the primary photoreceptor responsible for perceiving red (R) and far-red (FR) light in maize. We found that maize phyB physically interacts with the LIGULELESS1 (LG1), a classical key regulator of leaf angle, to coordinately regulate plant architecture and density tolerance. The abundance of LG1 is significantly increased by phyB under high R:FR light (low density) but rapidly decreases under low R:FR light (high density), correlating with variations in leaf angle and plant height under various densities. In addition, we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade. Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells. Taken together, these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance, providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.
Asunto(s)
Fitocromo B , Proteínas de Plantas , Zea mays , Zea mays/crecimiento & desarrollo , Zea mays/genética , Zea mays/metabolismo , Zea mays/efectos de la radiación , Fitocromo B/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Regulación de la Expresión Génica de las Plantas , Hojas de la Planta/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/efectos de la radiación , LuzRESUMEN
Leaf angle (LA) is a crucial factor that affects planting density and yield in maize. However, the regulatory mechanisms underlying LA formation remain largely unknown. In this study, we performed a comparative histological analysis of the ligular region across various maize inbred lines and revealed that LA is significantly influenced by a two-step regulatory process involving initial cell elongation followed by subsequent lignification in the ligular adaxial sclerenchyma cells (SCs). Subsequently, we performed both bulk and single-nucleus RNA sequencing, generated a comprehensive transcriptomic atlas of the ligular region, and identified numerous genes enriched in the hypodermal cells that may influence their specialization into SCs. Furthermore, we functionally characterized two genes encoding atypical basic-helix-loop-helix (bHLH) transcription factors, bHLH30 and its homolog bHLH155, which are highly expressed in the elongated adaxial cells. Genetic analyses revealed that bHLH30 and bHLH155 positively regulate LA expansion, and molecular experiments demonstrated their ability to activate the transcription of genes involved in cell elongation and lignification of SCs. These findings highlight the specialized functions of ligular adaxial SCs in LA regulation by restricting further extension of ligular cells and enhancing mechanical strength. The transcriptomic atlas of the ligular region at single-nucleus resolution not only deepens our understanding of LA regulation but also enables identification of numerous potential targets for optimizing plant architecture in modern maize breeding.
Asunto(s)
Regulación de la Expresión Génica de las Plantas , Hojas de la Planta , Proteínas de Plantas , Zea mays , Zea mays/genética , Zea mays/crecimiento & desarrollo , Zea mays/metabolismo , Zea mays/citología , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Perfilación de la Expresión Génica , Transcriptoma/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Núcleo Celular/metabolismo , Núcleo Celular/genéticaRESUMEN
Chlorinated organic pollutants constitute a significant category of persistent organic pollutants due to their widespread presence in the environment, which is primarily attributed to the expansion of agricultural and industrial activities. These pollutants are characterized by their persistence, potent toxicity, and capability for long-range dispersion, emphasizing the importance of their eradication to mitigate environmental pollution. While conventional methods for removing chlorinated organic pollutants encompass advanced oxidation, catalytic oxidation, and bioremediation, the utilization of biochar has emerged as a prominent green and efficacious method in recent years. Here we review biochar's role in remediating typical chlorinated organics, including polychlorinated biphenyls (PCBs), triclosan (TCS), trichloroethene (TCE), tetrachloroethylene (PCE), organochlorine pesticides (OCPs), and chlorobenzenes (CBs). We focus on the impact of biochar material properties on the adsorption mechanisms of chlorinated organics. This review highlights the use of biochar as a sustainable and eco-friendly method for removing chlorinated organic pollutants, especially when combined with biological or chemical strategies. Biochar facilitates electron transfer efficiency between microorganisms, promoting the growth of dechlorinating bacteria and mitigating the toxicity of chlorinated organics through adsorption. Furthermore, biochar can activate processes such as advanced oxidation or nano zero-valent iron, generating free radicals to decompose chlorinated organic compounds. We observe a broader application of biochar and bioprocesses for treating chlorinated organic pollutants in soil, reducing environmental impacts. Conversely, for water-based pollutants, integrating biochar with chemical methods proved more effective, leading to superior purification results. This review contributes to the theoretical and practical application of biochar for removing environmental chlorinated organic pollutants.
RESUMEN
Starch is a major storage carbohydrate in plants and is critical in crop yield and quality. Starch synthesis is intricately regulated by internal metabolic processes and external environmental cues; however, the precise molecular mechanisms governing this process remain largely unknown. In this study, we revealed that high red to far-red (high R:FR) light significantly induces the synthesis of leaf starch and the expression of synthesis-related genes, whereas low R:FR light suppress these processes. Arabidopsis phytochrome B (phyB), the primary R and FR photoreceptor, was identified as a critical positive regulator in this process. Downstream of phyB, basic leucine zipper transcription factor ELONGATED HYPOCOTYL5 (HY5) was found to enhance starch synthesis, whereas the basic helix-loop-helix transcription factors PHYTOCHROME INTERACTING FACTORs (PIF3, PIF4, and PIF5) inhibit starch synthesis in Arabidopsis leaves. Notably, HY5 and PIFs directly compete for binding to a shared G-box cis-element in the promoter region of genes encoding starch synthases GBSS, SS3, and SS4, which leads to antagonistic regulation of their expression and, consequently, starch synthesis. Our findings highlight the vital role of phyB in enhancing starch synthesis by stabilizing HY5 and facilitating PIFs degradation under high R:FR light conditions. Conversely, under low R:FR light, PIFs predominantly inhibit starch synthesis. This study provides insight into the physiological and molecular functions of phyB and its downstream transcription factors HY5 and PIFs in starch synthesis regulation, shedding light on the regulatory mechanism by which plants synchronize dynamic light signals with metabolic cues to module starch synthesis.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Regulación de la Expresión Génica de las Plantas , Fitocromo B , Almidón , Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/efectos de la radiación , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/metabolismo , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Regulación de la Expresión Génica de las Plantas/efectos de la radiación , Luz , Fototransducción , Fitocromo B/metabolismo , Fitocromo B/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/efectos de la radiación , Almidón/metabolismo , Almidón/biosíntesisRESUMEN
Waste activated sludge (WAS) as one of the major pollutants with a significant annual production, has garnered significant attention regarding its treatment and utilization. If improperly discharged, it not only caused environmental pollution but also led to the wastage of valuable resources. In this study, the microalgae growth and lipid accumulation using waste activated sludge extracts (WASE) under different temperature conditions were investigated. The highest lipid content (59.13%) and lipid productivity (80.41 mg L-1 d-1) were obtained at cultivation temperatures of 10 and 25 °C, respectively. It was found that microalgae can effectively utilize TN/TP/NH4+-N and other nutrients of WASE. The highest utilization rates of TP, TN and NH4+-N were achieved at a cultivation temperature of 10 °C, reaching 84.97, 77.49 and 92.32%, respectively. The algal fatty acids had carbon chains predominantly ranging from C14 to C18, making them suitable for biodiesel production. Additionally, a comprehensive analysis of transcriptomics and metabolomics revealed up-regulation of genes associated with triglyceride assembly, the antioxidant system of algal cells, and cellular autophagy, as well as the accumulation of metabolites related to the tricarboxylic acid (TCA) cycle and lipids. This study offers novel insights into the microscopic mechanisms of microalgae culture using WASE and approaches for the resource utilization of sludge.
Asunto(s)
Microalgas , Aguas del Alcantarillado , Lípidos , Biocombustibles , Temperatura , Perfilación de la Expresión Génica , BiomasaRESUMEN
A coupling technology for lipid production and adsorption of rare earth elements (REEs) using microalgae was studied in this work. The microalgae cell growth, lipid production, biochemical parameters and lipid profiles were investigated under different REEs (Ce3+, Gd3+and La3+). The results showed that the maximum lipid production was achieved at different concentrations of REEs, with lipid productivities of 300.44, 386.84 and 292.19 mg L-1 d-1 under treatment conditions of 100 µg L-1 Ce3+, 250 µg L-1 Gd3+ and 1 mg L-1 La3+, respectively. Moreover, the adsorption efficiency of Ce3+, Gd3+ and La3+exceeded 96.58 %, 93.06 % and 91.3 % at concentrations of 25-1000 µg L-1, 100-500 µg L-1 and 0.25-1 mg L-1, respectively. In addition, algal cells were able to adsorb 66.2 % of 100 µg L-1 Ce3+, 48.4 % of 250 µg L-1 Gd3+ and 59.9 % of 1 mg L-1 La3+. The combination of extracellular polysaccharide and algal cell wall could adsorb 25.2 % of 100 µg L-1 Ce3+, 44.5 % of 250 µg L-1 Gd3+ and 30.5 % of 1 mg L-1 La3+, respectively. These findings indicated that microalgae predominantly adsorbed REEs through the intracellular pathway. This study elucidates the mechanism of effective lipid accumulation and adsorption of REEs by microalgae under REEs stress conditions. It establishes a theoretical foundation for the efficient microalgae lipid production and REEs recovery from wastewater or waste residues containing REEs.
Asunto(s)
Metales de Tierras Raras , Microalgas , Biocombustibles , Adsorción , LípidosRESUMEN
OBJECTIVE: Idiopathic gingival fibromatosis (IGF) is a rare heterogeneous disease that results in the progressive and diffuse hyperplasia of gingival tissues. MicroRNAs are implicated in the development and progression of various tumors. The present study aimed to explore the potential roles and mechanisms of miR-148a-3p in IGF. METHODS: Gingival fibroblasts (GFs) were transfected with miR-148a-3p mimics, miR-148a-3p inhibitors, or siNPTX1, and then, the proliferation and apoptosis of GFs and the expression of related genes were evaluated using Cell Counting Kit-8 assays, 5-ethynyl-2'-deoxyuridine assays, flow cytometry, reverse transcription-quantitative polymerase chain reaction, and western blot analysis, respectively. RESULTS: miR-148a-3p was highly expressed in GFs of IGF (IGF-GFs) as compared with normal GFs (N-GFs). Overexpression of miR-148a-3p promoted the proliferation and inhibited the apoptosis of N-GFs, whereas downregulation of miR-148a-3p had the opposite effect in IGF-GFs. Knockdown of NPTX1 reversed miR-148a-3p-mediated effects in IGF-GFs. Dual-luciferase reporter assay confirmed that NPTX1 is a direct target of miR-148a-3p. CONCLUSION: These findings identify that miR-148a-3p could regulate cell proliferation and apoptosis by targeting NPTX1, providing new insights for the further study of the molecular mechanism and treatment of IGF.
RESUMEN
Thallium (Tl+) is a trace metal with extreme toxicity and is highly soluble in water, posing a great risk to ecological and human safety. This work aimed to investigate the role played by Tl+ in regulating lipid accumulation in microalgae and the removal efficiency of Tl+. The effect of Tl+ on the cell growth, lipid production and Tl+ removal efficiency of Parachlorella kessleri R-3 was studied. Low concentrations of Tl+ had no significant effect on the biomass of microalgae. When the Tl+ concentration exceeded 5 µg L-1, the biomass of microalgae showed significant decrease. The highest lipid content of 63.65% and lipid productivity of 334.55 mg L-1 d-1 were obtained in microalgae treated with 10 and 5 µg L-1 Tl+, respectively. Microalgae can efficiently remove Tl+ and the Tl+ removal efficiency can reach 100% at Tl+ concentrations of 0-25 µg L-1. The maximum nitric oxide (NO) level of 470.48 fluorescence intensity (1 × 106 cells)-1 and glutathione (GSH) content of 343.51 nmol g-1 (fresh alga) were obtained under 5 µg L-1 Tl+ stress conditions. Furthermore, the exogenous donor sodium nitroprusside (SNP) supplemented with NO was induced in microalgae to obtain a high lipid content (59.99%), lipid productivity (397.99 mg L-1 d-1) and GSH content (430.22 nmol g-1 (fresh alga)). The corresponding analysis results indicated that NO could participate in the signal transduction pathway through modulation of reactive oxygen species (ROS) signaling to activate the antioxidant system by increasing the GSH content to eliminate oxidative damage induced by Tl+ stress. In addition, NO regulation of ROS signaling may enhance transcription factors associated with lipid synthesis, which stimulates the expression of genes related to lipid synthesis, leading to increased lipid biosynthesis in microalgae. Moreover, it was found that the change in Tl+ had little effect on the fatty acid components and biodiesel properties. This study showed that Tl+ stress can promote lipid accumulation in microalgae for biodiesel production and simultaneously effectively remove Tl+, which provided evidence that NO was involved in signal transduction and antioxidant defense, and improved the understanding of the interrelation between NO and ROS to regulate lipid accumulation in microalgae.
Asunto(s)
Metales Pesados , Microalgas , Humanos , Talio/metabolismo , Antioxidantes , Especies Reactivas de Oxígeno/metabolismo , Biodegradación Ambiental , Biocombustibles , Glutatión , Lípidos , Transducción de Señal , BiomasaRESUMEN
In this study, a new microalgal strain, Asterarcys quadricellulare R-56, was isolated for biomass and lipid production. The effects of carbon and nitrogen sources and initial pH on the cell growth and lipid accumulation of strain R-56 were investigated. At 10 g L-1 glucose, 0.6 g L-1 sodium nitrate, and pH 7, the highest biomass of 4.18 g L-1 and lipid content of 43.66% were obtained. Microalgae had a broad pH tolerance in the range of 5-11, and the pH of the culture medium was close to neutral at the end of cultivation. The maximum contents of chlorophyll, carbohydrate, and protein under the recommended culture conditions were 19.47 mg mL-1, 21.80%, and 29.94%, respectively. Palmitic and palmitoleic acid contents in strain R-56 accounted for as high as 83.73% of total fatty acids. This study suggested that strain R-56 was a promising lipid producer for high-quality biodiesel production.
Asunto(s)
Chlorophyceae , Microalgas , Biocombustibles , Ácidos Grasos/metabolismo , Carbohidratos , Proteínas/metabolismo , BiomasaRESUMEN
Microalgae have become the hotspot of recent researches as heavy metals (HMs) adsorbent and biodiesel production feedstock. In this study, the cell growth, lipid production and Cr6+ removal of Parachlorella kessleri R-3 at pH 3.5 and 15 °C were investigated. It was found that low concentration of Cr6+ (0.5 to 2 mg/L) promoted the algal growth, whereas Cr6+ higher than 5 mg/L inhibited the growth of P. kessleri R-3. Biomass concentration (2.40 g/L) and lipid productivity (131.79 mg/L d-1) reached the highest at 2 mg/L Cr6+, and lipid content (61.03 %) reached the highest at 5 mg/L Cr6+. The maximum Cr6+ removal efficiency of 91 % was obtained at 0.5 mg/L Cr6+ treatment. Furthermore, fatty acid composition analysis showed that strain R-3 had a high C16-18 content of 74.88-89.21 %. This study provides new insight into the treatment of HMs and lipid production in cold regions.
Asunto(s)
Metales Pesados , Microalgas , Cromo , Biocombustibles , Temperatura , Ácidos Grasos , Ácidos , BiomasaRESUMEN
In this study, a stacked integrated system with anaerobic bioelectrochemical system (BES) and aerobic moving bed biofilm reactor (MBBR) was developed to improve the decolorization and mineralization of azo dye. This stacked BES-MBBR exhibited better performance with acid orange (AO7) decolorization of 96.4 ± 0.6% and chemical oxygen demand (COD) removal of 87.7 ± 4.4%. Contribution of each module in the BES and MBBR stages indicated that BES modules enhanced the pretreatment process in AO7 decolorization, and MBBR played an important role in further removal of COD. The mechanism analysis indicated that the azo bond was cleaved with reductive decolorization at biocathode in the anaerobic BES stages, and then the intermediate products can be further oxidized with COD removal in the aerobic MBBR stage. This work demonstrated that the integrated system with stacked anaerobic BES and aerobic MBBR could provide a promising way for the pretreatment and post-treatment of refractory wastewater.
Asunto(s)
Compuestos Azo , Biopelículas , Anaerobiosis , Compuestos Azo/química , Reactores Biológicos , Colorantes/química , Eliminación de Residuos LíquidosRESUMEN
bHLH family proteins play an important role in plant stress response. However, the molecular mechanism regulating the salt response of bHLH is largely unknown. This study aimed to investigate the function and regulating mechanism of the sweet sorghum SbbHLH85 during salt stress. The results showed that SbbHLH85 was different from its homologs in other species. Also, it was a new atypical bHLH transcription factor and a key gene for root development in sweet sorghum. The overexpression of SbbHLH85 resulted in significantly increased number and length of root hairs via ABA and auxin signaling pathways, increasing the absorption of Na+. Thus, SbbHLH85 plays a negative regulatory role in the salt tolerance of sorghum. We identified a potential interaction partner of SbbHLH85, which was phosphate transporter chaperone PHF1 and modulated the distribution of phosphate, through screening a yeast two-hybrid library. Both yeast two-hybrid and BiFC experiments confirmed the interaction between SbbHLH85 and PHF1. The overexpression of SbbHLH85 led to a decrease in the expression of PHF1 as well as the content of Pi. Based on these results, we suggested that the increase in the Na+ content and the decrease in the Pi content resulted in the salt sensitivity of transgenic sorghum.
Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/fisiología , Proteínas de Plantas/fisiología , Raíces de Plantas/crecimiento & desarrollo , Tolerancia a la Sal/fisiología , Sorghum/fisiología , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Clonación Molecular , Perfilación de la Expresión Génica , Secuencias Hélice-Asa-Hélice , Proteínas de Transporte de Fosfato/metabolismo , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Estrés Salino , Tolerancia a la Sal/genética , Transducción de Señal , Sodio/metabolismo , Sorghum/genética , Sorghum/crecimiento & desarrolloRESUMEN
BACKGROUND: We aimed to explore the diagnostic values of miR-221-3p in serum and cerebrospinal fluid (CSF) for post-stroke depression (PSD) and to analyze the risk factors of the disease. METHODS: Admitted to the Second Affiliated Hospital of Harbin Medical University, Harbin, China from May 2013 to May 2020, 136 stroke patients were enrolled, among which 76 PSD patients were taken as a PSD group and 60 non-depressed patients were taken as a Non-PSD group. miR-221-3p expression in serum and CSF and concentrations of inflammatory cytokines (IL-6, TNF-α) in serum were detected, to analyze the diagnostic and prognostic values of the indicators for PSD. Correlations of miR-221-3p in serum with that in CSF, with the National Institute of Health Stroke Scale (NIHSS) score and the Hamilton Depression Rating Scale (HAMD) score, and with inflammatory cytokines were analyzed, so as to analyze the risk factors affecting the occurrence of PSD. RESULTS: Compared with the Non-PSD group, miR-221-3p remarkably upregulated in serum and CSF in the PSD group, and its areas under the curves (AUCs) for PSD identification were 0.900 and 0.925, respectively. According to the correlation analysis, miR-221-3p in serum was remarkably positively correlated with that in CSF, NIHSS score, HAMD score, IL-6 and TNF-α. In addition, a history of mental illness, NIHSS score, HAMD score, IL-6, TNF-α and miR-221-3p were risk factors of PSD. CONCLUSION: miR-221-3p in serum and CSF can be used as the diagnostic and risk warning indicators of PSD.
RESUMEN
The circadian clock is an endogenous timekeeper system that generates biological rhythms of approximately 24 h in most organisms. EARLY FLOWERING 3 (ELF3) and ELF4 were initially identified as negative regulators of flowering time in Arabidopsis thaliana. They were then found to play crucial roles in the circadian clock by integrating environmental light and ambient temperature signals and transmitting them to the central oscillator, thereby regulating various downstream cellular and physiological processes. At dusk, ELF3 acts as a scaffold, interacting with ELF4 and the transcription factor LUX ARRHYTHMO (PHYTOCLOCK1) to form an EVENING COMPLEX (EC). This complex represses the transcription of multiple circadian clock-related genes, thus inhibiting hypocotyl elongation and flowering. Subsequent studies have expanded knowledge about the regulatory roles of the EC in thermomorphogenesis and shade responses. In addition, ELF3 and ELF4 also form multiple complexes with other proteins including chromatin remodeling factors, histone deacetylase, and transcription factors, thus enabling the transcriptional repression of diverse targets. In this review, we summarize the recent advances in elucidating the regulatory mechanisms of ELF3 and ELF4 in plants and discuss directions for future research on ELF3 and ELF4.
Asunto(s)
Proteínas de Arabidopsis/fisiología , Arabidopsis/metabolismo , Factores de Transcripción/fisiología , Proteínas de Arabidopsis/metabolismo , Ritmo Circadiano , Regulación de la Expresión Génica de las Plantas , Factores de Transcripción/metabolismoRESUMEN
Heat stress poses a major threat to plant productivity and crop yields. The induction of heat shock proteins (HSPs) by heat shock factors is a principal defense response of plants exposed to heat stress. In this study, we identified and analyzed the heat stress-induced Whirly1 (SlWHY1) gene in tomato (Solanum lycopersicum). We generated various SlWHY1-overexpressing (OE) and SlWHY1-RNA interference (RNAi) lines to investigate the role of WHIRLY1 in thermotolerance. Compared with the wild type (WT), the OE lines showed less wilting, as reflected by their increased membrane stability and soluble sugar content and reduced reactive oxygen species (ROS) accumulation under heat stress. By contrast, RNAi lines with inhibited SlWHY1 expression showed the opposite phenotype and corresponding physiological indices under heat stress. The heat-induced gene SlHSP21.5A, encoding an endoplasmic reticulum-localized HSP, was upregulated in the OE lines and downregulated in the RNAi lines compared with the WT. RNAi-mediated inhibition of SlHSP21.5A expression also resulted in reduced membrane stability and soluble sugar content and increased ROS accumulation under heat stress compared with the WT. SlWHY1 binds to the elicitor response element-like element in the promoter of SlHSP21.5A to activate its transcription. These findings suggest that SlWHY1 promotes thermotolerance in tomato by regulating SlHSP21.5A expression.
Asunto(s)
Proteínas de Unión al ADN/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Choque Térmico/genética , Proteínas de Plantas/genética , Solanum lycopersicum/genética , Termotolerancia/genética , Arabidopsis/genética , Proteínas de Arabidopsis , Clorofila , Proteínas de Unión al ADN/metabolismo , Proteínas de Choque Térmico/metabolismo , Respuesta al Choque Térmico/genética , Calor , Solanum lycopersicum/fisiología , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/genética , Especies Reactivas de Oxígeno/metabolismo , Termotolerancia/fisiología , Nicotiana/genéticaRESUMEN
In this study, the growth and lipid accumulation of Scenedesmus sp. using different nanoparticles and light sources were investigated. Xenon lamp can produce a broad illumination spectrum, and exhibited better performance than light-emitting diode. SiC and g-C3N4 nanoparticles improved the biomass and lipid accumulation, whereas TiO2 and TiC nanoparticles had inhibitory influence on microalgae. Lipid production can be improved by oxidative stress produced by combination of nanoparticles and xenon lamp irradiation. At the optimal SiC nanoparticles concentration of 150â¯mgâ¯L-1 and photoperiod of 6:18â¯h, the maximum biomass concentration and total lipid content reached 3.18â¯gâ¯L-1 and 40.26%, respectively. The addition of SiC nanoparticles could promote the substrate utilization rate and induce stress condition, thereby enhancing the activity of acetyl-CoA carboxylase and lipid biosynthesis. This research shows that SiC nanoparticles addition combined with xenon lamp illumination is a promising strategy to promote microalgal growth and lipid accumulation.
Asunto(s)
Microalgas , Nanopartículas , Scenedesmus , Biomasa , Iluminación , Lípidos , XenónRESUMEN
This study evaluates a two-stage process by dark fermentation and microalgal cultivation for hydrogen and lipid production from different agricultural biomass residues, such as corn cob, corn stalk, rice straw and wheat straw. Results indicate that corn stalk was the best fermentation feedstock for hydrogen production and the highest accumulative hydrogen volume of 762.3â¯mLâ¯L-1 was obtained in batch mode. Dark fermentative effluent from corn stalk was rich in acetate and butyrate, and was favorable to lipid production. The maximum algal biomass and total lipid content reached 1461.1â¯mgâ¯L-1 and 35.2%, respectively. Meanwhile, the energy conversion efficiency in two-stage cultivation significantly increased from 5.78% to 16.96%. The system was stable and effective in long-term operation, and the average hydrogen production rate of 811.1â¯mLâ¯L-1â¯d-1 and lipid concentration of 588.5â¯mgâ¯L-1 were achieved. This study provides a promising process for enhancing energy production from agricultural wastes.
Asunto(s)
Biomasa , Fermentación , Hidrógeno , Lípidos , Microalgas , Oryza , Triticum , Zea maysRESUMEN
Light is one of the most important environmental factors affecting plant growth and development. Plants use shade avoidance or tolerance strategies to adjust their growth and development thus increase their success in the competition for incoming light. To investigate the mechanism of shade responses in maize (Zea mays), we examined the anatomical and transcriptional dynamics of the early shade response in seedlings of the B73 inbred line. Transcriptome analysis identified 912 differentially expressed genes, including genes involved in light signaling, auxin responses, and cell elongation pathways. Grouping transcription factor family genes and performing enrichment analysis identified multiple types of transcription factors that are differentially regulated by shade and predicted putative core genes responsible for regulating shade avoidance syndrome. For functional analyses, we ectopically over-expressed ZmHB53, a type II HD-ZIP transcription factor gene significantly induced by shade, in Arabidopsis thaliana. Transgenic Arabidopsis plants overexpressing ZmHB53 exhibited narrower leaves, earlier flowering, and enhanced expression of shade-responsive genes, suggesting that ZmHB53 might participates in the regulation of shade responses in maize. This study increases our understanding of the regulatory network of the shade response in maize and provides a useful resource for maize genetics and breeding.
Asunto(s)
Fototransducción , Transcriptoma , Zea mays/fisiología , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Luz , Proteínas de Plantas/genética , Plantones/genética , Plantones/fisiología , Factores de Transcripción/genética , Zea mays/genéticaRESUMEN
In this study, a novel integrated dark fermentative and microalgal bioreactor (IDFMB) was developed to simultaneously produce H2 and lipid from food waste. Under the optimized working volume ratio of 1:4, starch concentration of 7â¯gâ¯L-1 and initial pH of 7.0, the highest H2 production of 1643.5â¯mLâ¯L-1 and lipid yield of 515.6â¯mgâ¯L-1 were achieved. Microalgae can effectively utilize the main end products in dark fermentative effluent (acetic acid and butyric acid) for cell growth and lipid accumulation. Compared with single dark fermentation, the energy conversion efficiency from stimulated food waste was significantly enhanced by the IDFMB, which increased from 14.8% to 35%. Microbial community analysis revealed that Clostridium was the dominant bacteria for H2 generation, and the IDFMB can improve the survival environment of microorganisms. This study provides a novel strategy for efficient energy recovery from food waste.