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BACKGROUND: Preschoolers become anxious when they are about to undergo anesthesia and surgery, warranting the development of more appropriate and effective interventions. AIM: To explore the effect of static cartoons combined with dynamic virtual environments on preoperative anxiety and anesthesia induction compliance in preschool-aged children undergoing surgery. METHODS: One hundred and sixteen preschool-aged children were selected and assigned to the drug (n = 37), intervention (n = 40), and control (n = 39) groups. All the children received routine preoperative checkups and nursing before being transferred to the preoperative preparation room on the day of the operation. The drug group received 0.5 mg/kg midazolam and the intervention group treatment consisting of static cartoons combined with dynamic virtual environments. The control group received no intervention. The modified Yale Preoperative Anxiety Scale was used to evaluate the children's anxiety level on the day before surgery (T0), before leaving the preoperative preparation room (T1), when entering the operating room (T2), and at anesthesia induction (T3). Compliance during anesthesia induction (T3) was evaluated using the Induction Compliance Checklist (ICC). Changes in mean arterial pressure (MAP), heart rate (HR), and respiratory rate (RR) were also recorded at each time point. RESULTS: The anxiety scores of the three groups increased variously at T1 and T2. At T3, both the drug and intervention groups had similar anxiety scores, both of which were lower than those in the control group. At T1 and T2, MAP, HR, and RR of the three groups increased. The drug and control groups had significantly higher MAP and RR than the intervention group at T2. At T3, the MAP, HR, and RR of the drug group decreased and were significantly lower than those in the control group but were comparable to those in the intervention group. Both the drug and intervention groups had similar ICC scores and duration of anesthesia induction (T3), both of which were higher than those of the control group. CONCLUSION: Combining static cartoons with dynamic virtual environments as effective as medication, specifically midazolam, in reducing preoperative anxiety and fear in preschool-aged children. This approach also improve their compliance during anesthesia induction and helped maintain their stable vital signs.
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BACKGROUND: Gender consciousness directly affects the development of gender identity, which is a continuous and lifelong process. Meanwhile, hospitalization is a part of many children's lives and has an impact on their gender development. AIM: To investigate the current situation of gender identity in lower primary school children by conducting a survey of 202 hospitalized children in the lower grades and to provide a theoretical basis and foundation for the cultivation of gender identity and medical treatment of children based on the results. This study aims to inspire clinical medical staff to scientifically and reasonably arrange hospital wards for lower primary school children and pay attention to gender protection during the medical treatment process and to help children shape a unified and clear gender identity, which will enable them to better integrate into society and promote their personality development. METHODS: The gender consciousness scale for elementary and middle school students was used for the survey. RESULTS: Gender identity was already present in lower primary school children. The children's gender roles and gender equality consciousness were strong, exceeding the critical value, but their gender characteristics, gender identity, and gender ideal consciousness were weak. Children aged 6 had the weakest gender identity, and girls had significantly stronger gender identity than boys. CONCLUSION: Gender identity is already present in lower primary school children, providing a basis and inspiration for the cultivation of gender identity and medical treatment of lower primary school children. Clinical medical staff should be aware of and understand these results and should scientifically and reasonably arrange hospital wards for lower primary school children.
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Calmodulin-binding transcription activators (CAMTAs) are evolutionarily conserved transcription factors and have multi-functions in plant development and stress response. However, identification and functional analysis of tea plant (Camellia sinensis) CAMTA genes (CsCAMTAs) are still lacking. Here, five CsCAMTAs were identified from tea plant genomic database. Their gene structures were similar except CsCAMTA2, and protein domains were conserved. Phylogenetic relationship classified the CsCAMTAs into three groups, CsCAMTA2 was in group I, and CsCAMTA1, 3 and CsCAMTA4, 5 were, respectively, in groups II and III. Analysis showed that stress and phytohormone response-related cis-elements were distributed in the promoters of CsCAMTA genes. Expression analysis showed that CsCAMTAs were differentially expressed in different organs and under various stress treatments of tea plants. Three-hundred and four hundred-one positive co-expressed genes of CsCAMTAs were identified under cold and drought, respectively. CsCAMTAs and their co-expressed genes constituted five independent co-expression networks. KEGG enrichment analysis of CsCAMTAs and the co-expressed genes revealed that hormone regulation, transcriptional regulation, and protein processing-related pathways were enriched under cold treatment, while pathways like hormone metabolism, lipid metabolism, and carbon metabolism were enriched under drought treatment. Protein interaction network analysis suggested that CsCAMTAs could bind (G/A/C)CGCG(C/G/T) or (A/C)CGTGT cis element in the target gene promoters, and transcriptional regulation might be the main way of CsCAMTA-mediated functional regulation. The study establishes a foundation for further function studies of CsCAMTA genes in stress response.
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Caffeine is a characteristic bioactive compound in tea and coffee plants, which is synthesized and accumulated extensively in leaves and seeds. However, little is known about the regulatory mechanism of caffeine synthesis in plants. This study compared the caffeine metabolite between tea and coffee plants. We found that tea leaves contained significantly higher caffeine than coffee leaves, which is perhaps due to more members of N-methyltransferase (NMT) genes as well as higher expression levels in tea plants. Substantial numbers of transcription factors were predicted to be involved in caffeine biosynthesis regulation, combining weighted gene co-expression network analysis and the cis-element of NMT promoter analysis in tea and coffee plants. Furthermore, analysis of the transcription factors from the caffeine-related modules suggested that the regulatory mechanism of caffeine biosynthesis was probably partly conservative in tea and coffee plants. This study provides an essential resource for the regulatory mechanism of caffeine biosynthesis in plants.
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Cafeína , Camellia sinensis , Cafeína/metabolismo , Camellia sinensis/genética , Camellia sinensis/metabolismo , Café/metabolismo , Perfilação da Expressão Gênica , Chá/metabolismoRESUMO
Alcohol dehydrogenase (ADH) is a vital enzyme in the biosynthesis pathway of six-carbon volatiles in plants. However, little is known about its functions in tea plants. Here, we identified two ADH genes (CsADH1 and CsADH2). An in vitro protein expression assay showed that both CsADH1 and CsADH2 proteins can catalyze the reduction of (Z)-3-hexenal into (Z)-3-hexenol. Subcellular localization revealed that both CsADH1 and CsADH2 proteins were predominantly localized in the nucleus and cytosol. CsADH1 had high transcripts in young stems in autumn, while CsADH2 showed extremely high expression levels in stems and roots. The expression of CsADH2 was mainly downregulated under ABA treatment, while CsADH1 and CsADH2 transcripts were significantly lower under MeJA treatment at 12 and 24 h. Under cold treatment, CsADH1 transcripts first decreased and then increased, while CsADH2 demonstrated an almost opposite expression pattern. Notably, CsADH2 was significantly upregulated under simulated Ectropis obliqua invasion. Gene suppression by antisense oligonucleotides (AsODNs) demonstrated that AsODN_ADH2 treatment significantly reduced CsADH2 transcripts and the abundance of (Z)-3-hexenol products. The results indicate that the two CsADH genes may play an important role in response to (a)biotic stresses and in the process of (Z)-3-hexenol biosynthesis.
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Camellia sinensis , Álcool Desidrogenase/genética , Aldeídos , Camellia sinensis/genética , Camellia sinensis/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , CháRESUMO
To get a more detailed understanding of the interaction between tea plant (Camellia sinensis) and tea geometrids (Ectropis obliqua), transcriptomic profile in undamaged adjacent leaf (TGL) of tea geometrids fed local leaves (LL) was investigated for the first time. Here, approximately 245 million clean reads contained 39.39 Gb of sequence data were obtained from TGL. Further analysis revealed that systemic response was induced in TGL after tea geometrids feeding on LL, although the defense response was weaker than that in LL. The differentially expressed genes (DEGs) identification analysis showed little overlap of DEGs between TGL and LL. Comparative transcriptome analysis suggested that JA signal regulated resistant pathway was induced in LL; whereas primary metabolism pathway was activated in TGL in response to tea geometrids feeding. This study reveals a novel resistance mechanism of TGL to tea geometrids feeding.
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Camellia sinensis/fisiologia , Perfilação da Expressão Gênica , Mariposas/fisiologia , Animais , Camellia sinensis/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Folhas de Planta/genéticaRESUMO
A novel nitrogen-containing graphitic mesoporous carbon was prepared through MnO-templated method using polyacrylonitrile (PAN) as both carbon and nitrogen sources, and MnCO3 as both template and catalyst precursors. The effects of preparation conditions on the physicochemical properties of obtained samples were systematically investigated. The results showed that as the decrease of the weight ratios of PAN and MnO (2:1-1:4), the increase of carbonization temperature (700-900 °C) and pre-oxidation temperature (180-200 °C), the samples had higher specific surface area, mesopores volume and ratios, up to 507 m2/g, 0.824 cm3/g and 96.83%, respectively. Moreover, the prepared samples presented relatively high graphitic degree and nitrogen contents (~2.21%). The adsorption capacity for acid red 88 (AR88) was as high as 309 mg/g, which were dramatically affected by the mesoporous properties and C- and N-containing groups on the surface of prepared carbon. The rich graphic carbon and pyridine-N in mesoporous carbon generated π-π dispersion and electrostatic interaction with AR88, respectively, which jointly were responsible for the adsorption process. The results of the isotherm and kinetic studies indicated that the AR88 adsorption on mesoporous carbon could be well depicted using Langmuir model and pseudo-2nd-order model.
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In this study, nitrogen-tailored hierarchical meso-/micro-porous activated carbons were successfully fabricated from cypress sawdust by H3PO4 activation with further nitrogen modification using three kinds of nitrogen source (i.e. nitic acid, urea and melamine). The produced carbons were used as adsorbents for CO2 capture. The physic-chemical properties of the produced carbons were characterized by N2 adsorption-desorption, fourier-transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The effects of pore structure and nitrogen content on CO2 adsorption were investigated. It was found that H3PO4 activation would turn cypress sawdust into mesoporous carbon (AC), nitrogen doping could induce the development of microporosity and also increase the basicity of the carbon framework, which favoured for CO2 adsorption. Among the nitrogen-tailed carbons, HNO3-treated activated carbon (AC-N) showed the highest V mic (0.127â cm3/g), the largest CO2 adsorption capacity (2.8â mmol/g at 273â K, 1â bar) and the best CO2/N2 selectivity as compared to urea and melamine treated ones. The adsorption experiments showed that the presence of microporosity and pyrrolic-N on the carbons were responsible for CO2 adsorption, the oxygen functional groups on AC-N might also contribute to higher CO2 uptake, and the mesoporous structure could favour for the fast mass transfer of CO2. The results of CO2 adsorption heat confirmed the high affinity of the prepared carbons to CO2. This study provides a strategy to produce hierarchical meso-/micro-porous activated carbons with enriched nitrogen functional groups, which favoured for CO2 adsorption.
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Carvão Vegetal , Nitrogênio , Adsorção , Dióxido de Carbono , PorosidadeRESUMO
MAIN CONCLUSION: The roles of microRNA-mediated epigenetic regulation were highlighted in the bud dormancy-activity cycle, implying that certain differentially expressed miRNAs play crucial roles in apical bud burst, such as csn-miR319c/TCP2. microRNAs (miRNAs) are a class of small non-coding RNAs that regulate gene expression by targeting mRNA transcripts for cleavage or directing translational inhibition. To investigate whether miRNAs regulate bud dormancy-activation transition in tea plant, which largely affects the yield and price of tea products and adaptability of tea trees, we constructed small RNA libraries from three different periods of bud dormancy-burst transition. Through sequencing analysis, 262 conserved and 83 novel miRNAs were identified, including 118 differentially expressed miRNAs. Quantitative RT-PCR results for randomly selected miRNAs exhibited that our comprehensive analysis is highly reliable and accurate. The content of caffeine increased continuously from the endodormancy bud to flushing bud, and differentially expressed miRNAs coupling with their targets associated with bud burst were identified. Remarkably, csn-miR319c was downregulated significantly from the quiescent bud to burst bud, while its target gene CsnTCP2 (TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTOR 2) displayed opposite expression patterns. Co-transformation experiment in tobacco demonstrated that csn-miR319c can significantly suppress the functions of CsnTCP2. This study on miRNAs and the recognition of target genes could provide new insights into the molecular mechanism of the bud dormancy-activation transition in tea plant.
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Camellia sinensis/genética , Regulação da Expressão Gênica de Plantas/genética , MicroRNAs/genética , Sequência de Aminoácidos , Camellia sinensis/crescimento & desenvolvimento , Regulação para Baixo , Epigênese Genética , Regulação da Expressão Gênica no Desenvolvimento , Biblioteca Gênica , Filogenia , Folhas de Planta/citologia , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA de Plantas/genética , Alinhamento de Sequência , Nicotiana/citologia , Nicotiana/genéticaRESUMO
Chemical insecticides are widely used for pest control worldwide. However, the impact of insecticides on indirect plant defense is seldom reported. Here, using tea plants and the pesticide imidacloprid, effects of chemical insecticides on C6-green leaf volatiles (GLVs) anabolism and release were investigated first time. Compared with the non-treated control plants, the treatment of imidacloprid resulted in the lower release amount of key GLVs: (Z)-3-hexenal, n-hexenal, (Z)-3-hexene-1-ol and (Z)-3-Hexenyl acetate. The qPCR analysis revealed a slight higher transcript level of the CsLOX3 gene but a significantly lower transcript level of CsHPL gene. Our results suggest that imidacloprid treatment can have a negative effect on the emission of GLVs due to suppressing the critical GLVs synthesis-related gene, consequently affecting plant indirect defense.
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Camellia sinensis/efeitos dos fármacos , Camellia sinensis/metabolismo , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Acetatos/metabolismo , Aldeídos/metabolismo , Alcenos/metabolismo , Camellia sinensis/genética , Folhas de Planta/genéticaRESUMO
MAIN CONCLUSION: Circular RNA (circRNA) discovery, expression patterns and experimental validation in developing tea leaves indicates its correlation with circRNA-parental genes and potential roles in ceRNA interaction network. Circular RNAs (circRNAs) have recently emerged as a novel class of abundant endogenous stable RNAs produced by circularization with regulatory potential. However, identification of circRNAs in plants, especially in non-model plants with large genomes, is challenging. In this study, we undertook a systematic identification of circRNAs from different stage tissues of tea plant (Camellia sinensis) leaf development using rRNA-depleted circular RNA-seq. By combining two state-of-the-art detecting tools, we characterized 3174 circRNAs, of which 342 were shared by each approach, and thus considered high-confidence circRNAs. A few predicted circRNAs were randomly chosen, and 20 out of 24 were experimental confirmed by PCR and Sanger sequencing. Similar in other plants, tissue-specific expression was also observed for many C. sinensis circRNAs. In addition, we found that circRNA abundances were positively correlated with the mRNA transcript abundances of their parental genes. qRT-PCR validated the differential expression patterns of circRNAs between leaf bud and young leaf, which also indicated the low expression abundance of circRNAs compared to the standard mRNAs from the parental genes. We predicted the circRNA-microRNA interaction networks, and 54 of the differentially expressed circRNAs were found to have potential tea plant miRNA binding sites. The gene sets encoding circRNAs were significantly enriched in chloroplasts related GO terms and photosynthesis/metabolites biosynthesis related KEGG pathways, suggesting the candidate roles of circRNAs in photosynthetic machinery and metabolites biosynthesis during leaf development.
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Camellia sinensis/genética , MicroRNAs/genética , RNA/genética , Processamento Alternativo , Sítios de Ligação , Camellia sinensis/crescimento & desenvolvimento , Diferenciação Celular , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Especificidade de Órgãos , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , RNA Circular , RNA Mensageiro/genética , RNA de Plantas/genética , Análise de Sequência de RNARESUMO
Mesoporous carbon is considered as the most effective adsorbent for dyes with large molecule diameter. In this study, an ultra-high surface area mesoporous carbon was derived using a kind of new template precursors (manganese salts), i.e. manganese carbonate (MC), manganese oxalate (MO) and manganese acetate (MA). The XRD results demonstrated that after the pyrolysis of the mixture of manganese salts and poly(vinyl alcohol) (PVA) over 500⯰C, MnO was only the Mn species on carbon and the particle sizes of the generated MnO were in the range of 1.92-15.11â¯nm, with the lowest value derived from MO. All prepared carbons presented evident mesoporous characteristics, with higher specific surface areas (SBET) at 2138â¯m2/g, mesopore volume (Vmeso) at 3.56â¯cm3/g, and mesopore ratiosâ¯>â¯95%, together with the lowest and narrowest mesopore size distribution, for the MO-templated sample. The sample had high adsorption capacities for methylene blue, up to 1791â¯mg/g, and extremely fast adsorption rates with the adsorption equilibrium time within 1â¯min, which was significantly higher than previous studies. The results demonstrated that the novel MnO-templated method is very promising for the preparation of high surface area mesoporous carbon for highly effective adsorption of methylene blue.
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Adsorção , Compostos de Manganês/química , Azul de Metileno/isolamento & purificação , Óxidos/química , Carbono/química , Corantes/química , Corantes/isolamento & purificação , Tamanho da Partícula , Porosidade , Propriedades de SuperfícieRESUMO
Novel biochar was prepared from plant-based biomass by the addition of nitrogen-containing phosphates (NCPs), including ammonia phosphate (AP), ammonia polyphosphate (APP) and urea phosphate (UP). The results demonstrated that with the addition of NCPs, the yield of biochar could be significantly increased from about 30% to up to about 60%. The pore structure of the biochar was significantly improved, and the AP-prepared biochar obtained a higher S BET and V tot of 798 m2 g-1 and 0.464 cm3 g-1, respectively. Moreover, the surface chemistry of the NCP-prepared biochar was affected, and N heteroatoms could be successfully doped on the surface of biochar, up to 4.16%. Furthermore, through TG-FTIR and XPS analysis, some possible interactions between plant-based biomass and NCPs during the pyrolysis process were proposed to explore the mechanisms of the preparation process, including the P route and N route, in which the H3PO4 and NH3 gradually generated during the heating process played the dominant roles for the high yield N-doped biochar. All the NCP-prepared biochar presented good toluene adsorption capacities from 175.9 to 496.2 mg g-1, which were significantly higher than that of blank char (6.5 mg g-1).
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Worldwide, gastric cancer is one of the most fatal cancers. Epigenetic alterations in gastric cancer play important roles in silencing of tumor suppressor genes. We previously found that CXXC finger protein 4 (CXXC4) was a novel tumor suppressor in gastric cancer. In this report, we demonstrated that CXXC4 inhibited growth of gastric cancer cells as a pro-apoptotic factor. This inhibition could be reversed by the pan-caspase inhibitor called Z-VAD-FMK. However, CXXC4 with mutations in its DNA binding domain failed to induce apoptosis. Growth differentiation factor 15 (GDF15) was identified as one of potential targets responsible for CXXC4-induced apoptosis. CXXC4 activated GDF15 transcription through enhancing the interaction of transcription factor Sp1 with GDF15 promoter. In summary, the nuclear protein CXXC4 activated apoptosis in gastric cancer through up-regulating its novel potential downstream target GDF15. GDF15 might be a promising target for clinical treatment of gastric cancer with CXXC4 deficiency.
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Increasing evidences have demonstrated that long noncoding RNAs (LncRNAs) play a significant role in the development of tumor. However, the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in uveal melanoma remains unknown. In this study, we demonstrated that the expression of MALAT1 was upregulated in the uveal melanoma tissues compared to normal tissues. Among them, MALAT1 was upregulated in 72% (18/25) uveal melanoma tissues compared to their paired normal tissues. Knockdown of MALAT1 suppressed uveal melanoma cell proliferation, colony information, invasion and migration. Moreover, we showed that knockdown of MALAT1 promoted miR-140 expression and suppressed Slug and ADAM10 expression in the MUM-2C cell. In addition, we demonstrated that miR-140 was downregulated in the uveal melanoma tissues compared to normal tissues and cell lines. The expression level of MALAT1 was inversely correlated with the expression level of miR-140 in uveal melanoma tissues. These results suggested that MALAT1 served as an oncogenic LncRNA in the development of uveal melanoma.
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CircRNAs are a class of endogenous RNA that regulates gene expression at the post-transcriptional or transcriptionallevel through interacting with other molecules or microRNAs. Increasing studies have demonstrated that circRNAs play a crucial role in biology processes. CircRNAs are proved as potentialbiomarkers in many diseases including cancers. However, the role of Cdr1as in Hepatocellular carcinoma (HCC) remains to be elucidated. We demonstrated that Cdr1as expression was upregulated in HCC tissues compared with the adjacent non-tumor tissues. In addtion, miR-7 expression was downregulated in HCC tissues compared with the adjacent non-tumor tissues. Moreover, the expression level of miR-7 was inversely correlated with that in HCC tissues. Knockdown of Cdr1as suppressed the HCC cell proliferation and invasion. Overexpression of miR-7 inhibited the HCC cell proliferation and invasion. Overexpression of miR-7 could suppress the direct target gene CCNE1 and PIK3CD expression. Knockdown of Cdr1as suppressed the expression of miR-7 and also inhibited the CCNE1 and PIK3CD expression. Furthermore, knockdown of Cdr1as suppressed the HCC cell proliferation and invasion through targeting miR-7. These data suggested that Cdr1as acted as an oncogene partly through targeting miR-7 in HCC.
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Carcinoma Hepatocelular/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/metabolismo , MicroRNAs/biossíntese , Oncogenes , RNA Longo não Codificante/metabolismo , RNA Neoplásico/metabolismo , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Proliferação de Células/genética , Classe I de Fosfatidilinositol 3-Quinases/biossíntese , Classe I de Fosfatidilinositol 3-Quinases/genética , Feminino , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Masculino , MicroRNAs/genética , Invasividade Neoplásica , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , RNA Longo não Codificante/genética , RNA Neoplásico/genética , Células Tumorais CultivadasRESUMO
Amino acid transporters (AATs) play important roles in transporting amino acid across cellular membranes and are essential for plant growth and development. To date, the AAT gene family in soybean (Glycine max L.) has not been characterized. In this study, we identified 189 AAT genes from the entire soybean genomic sequence, and classified them into 12 distinct subfamilies based upon their sequence composition and phylogenetic positions. To further investigate the functions of these genes, we analyzed the chromosome distributions, gene structures, duplication patterns, phylogenetic tree, tissue expression patterns of the 189 AAT genes in soybean. We found that a large number of AAT genes in soybean were expanded via gene duplication, 46 and 36 GmAAT genes were WGD/segmental and tandemly duplicated, respectively. Further comprehensive analyses of the expression profiles of GmAAT genes in various stages of vegetative and reproductive development showed that soybean AAT genes exhibited preferential or distinct expression patterns among different tissues. Overall, our study provides a framework for further analysis of the biological functions of AAT genes in either soybean or other crops.
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Both biogas desulfurization and wastewater denitrification can be achieved simultaneously, when nitrate/nitrite is used as the electron acceptor for H2S oxidation. The main objective of this study was to investigate the influence of the molar ratio of sulfide/nitrate (S/N) on biogas desulfurization performance in a biotrickling filter (BTF) and a biobubble column (BBC). The results show that with the decrease of the S/N ratios from 3.6 to 0.7, the removal efficiencies of H2S increased from about 66 to 100 %, while the removal of nitrate decreased from 100 to 70 % in the two bioreactors. The BTF has a better and more stable desulfurization performance than the BBC does, which could be attributed to their different gas-liquid contacting modes. With the increase of the S/N ratios from 1.0 to 2.5 in the BTFs, the removal of H2S in biogas was affected slightly, while the percentages of the produced sulfate decreased evidently. In addition, different supplying methods of nitrate wastewater, i.e., intermittent and continuous, did not affect the removal of H2S significantly, while the intermittent addition of nitrate wastewater increased the percentages of sulfate and denitrification performance.
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Biocombustíveis , Reatores Biológicos , Sulfeto de Hidrogênio/isolamento & purificação , Nitratos/análise , Sulfetos/análise , Anaerobiose , Desnitrificação , Filtração/instrumentação , Águas Residuárias/químicaRESUMO
In this study, five kinds of iron ores, limonite, hematite, manganese ore, magnetite and lava rock, were used as the in situ desulfurizers in the anaerobic digestion reactors to investigate their effects on controlling H2S in biogas. The results show that the addition of the five iron ores could significantly control the content of H2S in biogas, with the best performance for limonite. As limonite dosages increase (10-60 g/L), the contents of H2S in biogas were evidently decreased in the digesters with different initial sulfate concentrations (0-1000 mg/L). After the anaerobic digestion, the removed sulfur was mostly deposited on the surface of limonite. A possible mechanism of H2S control in biogas by limonite was proposed preliminarily, including adsorption, FeS precipitation, and Fe (III) oxidation. The results demonstrated that limonite was a promising in situ desulfurizer for controlling H2S in biogas with low cost and high efficiency.
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Biocombustíveis , Reatores Biológicos/microbiologia , Compostos Férricos/metabolismo , Sulfeto de Hidrogênio/metabolismo , Esterco/microbiologia , Enxofre/metabolismo , AnaerobioseRESUMO
Biological removal of hydrogen sulfide in biogas is an increasingly adopted alternative to the conventional physicochemical processes, because of its economic and environmental benefits. In this study, a microaerobic biofiltration system packed with polypropylene carrier was used to investigate the removal of high concentrations of H2S contained in biogas from an anaerobic digester. The results show that H2S in biogas was removed completely under different inlet concentrations of H2S from 2065 ± 234 to 7818 ± 131 ppmv, and the elimination capacity of H2S in the filter achieved about 122 g H2S/m(3)/h. It was observed that the content of CH4 in biogas increased after the biogas biodesulfurization process, which was beneficial for the further utilization of biogas. The elemental sulfur and sulfate were the main sulfur species of H2S degradation, and elemental sulfur was dominant (about 80 %) under high inlet H2S concentration. The results of terminal restriction fragment length polymorphism (T-RFLP) and fluorescence in situ hybridization (FISH) show that the population of sulfide-oxidizing bacteria (SOB) species in the filter changed with different concentrations of H2S. The microaerobic biofiltration system allows the potential use of biogas and the recovery of elemental sulfur resource simultaneously.