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Chloroplast biogenesis is dependent on master regulators from the GOLDEN2-LIKE (GLK) family of transcription factors. However, glk mutants contain residual chlorophyll, indicating that other proteins must be involved. Here, we identify MYB-related transcription factors as regulators of chloroplast biogenesis in the liverwort Marchantia polymorpha and angiosperm Arabidopsis thaliana. In both species, double-mutant alleles in MYB-related genes show very limited chloroplast development, and photosynthesis gene expression is perturbed to a greater extent than in GLK mutants. Genes encoding enzymes of chlorophyll biosynthesis are controlled by MYB-related and GLK proteins, whereas those allowing CO2 fixation, photorespiration, and photosystem assembly and repair require MYB-related proteins. Regulation between the MYB-related and GLK transcription factors appears more extensive in A. thaliana than in M. polymorpha. Thus, MYB-related and GLK genes have overlapping as well as distinct targets. We conclude that MYB-related and GLK transcription factors orchestrate chloroplast development in land plants.
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Ilarviruses are a relatively understudied but important group of plant RNA viruses that includes a number of crop pathogens. Their genomes comprise three RNA segments encoding two replicase subunits, movement protein, coat protein (CP), and (in some ilarvirus subgroups) a protein that suppresses RNA silencing. Here we report that, in many ilarviruses, RNA3 encodes an additional protein (termed CP-RT) as a result of ribosomal readthrough of the CP stop codon into a short downstream readthrough (RT) ORF. Using asparagus virus 2 as a model, we find that CP-RT is expressed in planta where it functions as a weak suppressor of RNA silencing. CP-RT expression is essential for persistent systemic infection in leaves and shoot apical meristem. CP-RT function is dependent on a putative zinc-finger motif within RT. Replacing the asparagus virus 2 RT with the RT of an ilarvirus from a different subgroup restored the ability to establish persistent infection. These findings open up a new avenue for research on ilarvirus silencing suppression, persistent meristem invasion and vertical transmission.
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Ilarvirus , Enfermedades de las Plantas , Interferencia de ARN , Proteínas de la Cápside/genética , Proteínas de la Cápside/metabolismo , Codón de Terminación/genética , Ilarvirus/genética , Nicotiana/virología , Nicotiana/genética , Nicotiana/metabolismo , Enfermedades de las Plantas/virología , Enfermedades de las Plantas/genética , ARN Viral/genética , ARN Viral/metabolismo , ARN Polimerasa Dependiente del ARN/genética , ARN Polimerasa Dependiente del ARN/metabolismo , Proteínas Virales/genética , Proteínas Virales/metabolismoRESUMEN
Surface waves are known for their mechanical role in coastal processes that influence the weather and climate. However, their chemical impact, particularly on the transformation of pyrogenic carbon, is poorly understood. Pyrogenic carbon is generally assumed to show negligible postformational alteration of its stable carbon isotope composition. Here we present an electrochemical interaction of pyrogenic carbon with the sprayed seawater microdroplets resulting from wave breaking, driven by the galvanic coupling between the microdroplet water-carbon interfaces and the microdroplet water-vapor interfaces. This enables refractory pyrogenic carbon to rapidly degrade via the oxygenation and mineralization reaction, which makes it â¼2.6 enriched in 13C, far exceeding the generally assumed postformation alteration values (<0.5) of pyrogenic carbon. The unique chemical dynamics of seawater microdroplets provide new insights into the discrepancy in carbon isotope signatures between riverine and marine black carbon, emphasizing the potential of coastal oceans for carbon sequestration in the global carbon cycle.
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Vacuum ultraviolet photoionization (VUV-PI) is a soft ionization technique that operates under pressures ranging from vacuum to ambient pressure. VUV-PI has played an essential role in direct sampling mass spectrometry. In this study, new ionization processes initiated by photoelectrons have been studied through the inclusion of a radio frequency (RF) electric field at different pressures. After deducting the contribution of single photoionization (SPI), the signal intensity of 1 ppmv toluene (C7H8+) in Ar was approximately 5-fold higher than that in N2. Mixed gases with different ionization energies (IEs) and excitation energies (EEs) were further investigated to reveal that metastable species were involved in the enhancement process. Reactant ions were produced by photoelectron impact ionization (PEI), which further triggered ion-molecule reactions, i.e., chemical ionization (CI). Metastable species were produced by photoelectron impact excitation (PEE), which further triggered Penning ionization (PenI). Analytes with IEs above 10.6 eV, such as CO2 (IE = 13.78 eV) and CHCl3 (IE = 11.37 eV), could be sensitively ionized by PenI with a sensitivity comparable to SPI. Except for the contribution of SPI, the dominant ionization process was switched from PEI-CI to PenI when the pressure was elevated from 50 to 500 Pa, as the electron energy gradually decreased and was only able to produce metastable states based on the kinetic energy balance equation of electrons. The conversion processes and conditions from PEI-CI to PenI will provide novel insights to develop new selective and sensitive VUV-PI sources and understand the ionization mechanism in other discharge ionization sources.
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Efficient and accurate acquisition of cellular biomolecular information is crucial for exploring cell fate, achieving early diagnosis, and the effective treatment of various diseases. However, current DNA biosensors are mostly limited to single-target detection, with few complex logic circuits for comprehensive analysis of three or more targets. Herein, we designed a sea anemone-like DNA nanomachine based on DNA strand displacement composed of three logic gates (YES-AND-YES) and delivered into the cells using gold nano bipyramid carriers. The AND gate activation depends on the trigger chain released by upstream DNA strand displacement reactions, while the output signal relies on the downstream DNAzyme structure. Under the influence of diverse inputs (including enzymes, miRNA, and metal ions), the interconnected logic gates simultaneously perform logical analysis on multiple targets, generating a unique output signal in the YES/NO format. This sensor can successfully distinguish healthy cells from tumor cells and can be further used for the diagnosis of different tumor cells, providing a promising platform for accurate cell-type identification.
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ADN Catalítico , Anémonas de Mar , Animales , Anémonas de Mar/genética , ADN/química , ADN Catalítico/química , Lógica , Oro , Computadores MolecularesRESUMEN
The accurate quantification of cancer-derived exosomes, which are emerging as promising noninvasive biomarkers for liquid biopsies in the early diagnosis of cancer, is becoming increasingly imperative. In our work, we developed a magnetically controlled photothermal, colorimetric, and fluorescence trimode aptasensor for human gastric cancer cell (SGC-7901)-derived exosomes. This sensor relied on CP/Mn-PBA DSNBs nanocomposites, created by decorating copper peroxide (CP) nanodots on polyethyleneimine-modified manganese-containing Prussian blue analogues double-shelled nanoboxes (PEI-Mn-PBA DSNBs). Through self-assembly, we attached CD63 aptamer-labeled CP/Mn-PBA DSNBs (Apt-CP/Mn-PBA DSNBs) to complementary DNA-labeled magnetic beads (cDNA-MB). During exosome incubation, these aptamers preferentially formed complexes with exosomes, and we efficiently removed the released CP/Mn-PBA DSNBs by using magnetic separation. The CP/Mn-PBA DSNBs exhibited high photoreactivity and photothermal conversion efficiency under near-infrared (NIR) light, leading to temperature variations under 808 nm irradiation, correlating with different exosome concentrations. Additionally, colorimetric detection was achieved by monitoring the color change in a 3,3',5,5'-tetramethylbenzidine (TMB) system, facilitated by PEI modification, NIR-enhanced peroxidase-like activity of CP/Mn-PBA DSNBs and their capacity to generate Cu2+ and H2O2 under acidic conditions. Moreover, in the presence of Cu2+ and ascorbic acid (AA), DNA sequences could form dsDNA-templated copper nanoparticles (CuNPs), which emitted strong fluorescence at around 575 nm. Increasing exosome concentrations correlated with decreases in temperature, absorbance, and fluorescence intensity. This trimode biosensor demonstrated satisfactory ability in differentiating gastric cancer patients from healthy individuals using human serum samples.
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Aptámeros de Nucleótidos , Técnicas Biosensibles , Exosomas , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/diagnóstico , Cobre , Peróxidos , Peróxido de Hidrógeno , ColorimetríaRESUMEN
Common purslane (Portulaca oleracea) integrates both C4 and crassulacean acid metabolism (CAM) photosynthesis pathways and is a promising model plant to explore C4-CAM plasticity. Here, we report a high-quality chromosome-level genome of nicotinamide adenine dinucleotide (NAD)-malic enzyme (ME) subtype common purslane that provides evidence for 2 rounds of whole-genome duplication (WGD) with an ancient WGD (P-ß) in the common ancestor to Portulacaceae and Cactaceae around 66.30 million years ago (Mya) and another (Po-α) specific to common purslane lineage around 7.74 Mya. A larger number of gene copies encoding key enzymes/transporters involved in C4 and CAM pathways were detected in common purslane than in related species. Phylogeny, conserved functional site, and collinearity analyses revealed that the Po-α WGD produced the phosphoenolpyruvate carboxylase-encoded gene copies used for photosynthesis in common purslane, while the P-ß WGD event produced 2 ancestral genes of functionally differentiated (C4- and CAM-specific) beta carbonic anhydrases involved in the C4 + CAM pathways. Additionally, cis-element enrichment analysis in the promoters showed that CAM-specific genes have recruited both evening and midnight circadian elements as well as the Abscisic acid (ABA)-independent regulatory module mediated by ethylene-response factor cis-elements. Overall, this study provides insights into the origin and evolutionary process of C4 and CAM pathways in common purslane, as well as potential targets for engineering crops by integrating C4 or CAM metabolism.
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Portulaca , Portulaca/genética , Portulaca/metabolismo , Duplicación de Gen , Metabolismo Ácido de las Crasuláceas , Evolución Biológica , Filogenia , Fotosíntesis/genéticaRESUMEN
The large-scale deployment of quantum secret sharing (QSS) in quantum networks is currently challenging due to the requirements for the generation and distribution of multipartite entanglement states. Here we present an efficient source-independent QSS protocol utilizing entangled photon pairs in quantum networks. Through the post-matching method, which means the measurement events in the same basis are matched, the key rate is almost independent of the number of participants. In addition, the unconditional security of our QSS against internal and external eavesdroppers can be proved by introducing an equivalent virtual protocol. Our protocol has great performance and technical advantages in future quantum networks.
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KEY MESSAGE: The rust resistance genes Lr53 and Yr35 were introgressed into bread wheat from Aegilops longissima or Aegilops sharonensis or their S-genome containing species and mapped to the telomeric region of chromosome arm 6BS. Wheat leaf and stripe rusts are damaging fungal diseases of wheat worldwide. Breeding for resistance is a sustainable approach to control these two foliar diseases. In this study, we used SNP analysis, sequence comparisons, and cytogenetic assays to determine that the chromosomal segment carrying Lr53 and Yr35 was originated from Ae.longissima or Ae. sharonensis or their derived species. In seedling tests, Lr53 conferred strong resistance against all five Chinese Pt races tested, and Yr35 showed effectiveness against Pst race CYR34 but susceptibility to race CYR32. Using a large population (3892 recombinant gametes) derived from plants homozygous for the ph1b mutation obtained from the cross 98M71 × CSph1b, both Lr53 and Yr35 were successfully mapped to a 6.03-Mb telomeric region of chromosome arm 6BS in the Chinese Spring reference genome v1.1. Co-segregation between Lr53 and Yr35 was observed within this large mapping population. Within the candidate region, several nucleotide-binding leucine-rich repeat genes and protein kinases were identified as candidate genes. Marker pku6B3127 was completely linked to both genes and accurately predicted the absence or presence of alien segment harboring Lr53 and Yr35 in 87 tetraploid and 149 hexaploid wheat genotypes tested. We developed a line with a smaller alien segment (< 6.03 Mb) to reduce any potential linkage drag and demonstrated that it conferred resistance levels similar to those of the original donor parent 98M71. The newly developed introgression line and closely linked PCR markers will accelerate the deployment of Lr53 and Yr35 in wheat breeding programs.
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Aegilops , Mapeo Cromosómico , Resistencia a la Enfermedad , Genes de Plantas , Puccinia , Aegilops/genética , Aegilops/microbiología , Cromosomas de las Plantas/genética , Resistencia a la Enfermedad/genética , Introgresión Genética , Ligamiento Genético , Marcadores Genéticos , Fitomejoramiento , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Polimorfismo de Nucleótido Simple , Puccinia/fisiología , Triticum/genética , Triticum/microbiologíaRESUMEN
The aberrant activation of the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is known to contribute to the pathogenesis of various human inflammation-related diseases. However, to date, no small-molecule NLRP3 inhibitor has been used in clinical settings. In this study, we have identified SB-222200 as a novel direct NLRP3 inhibitor through the use of drug affinity responsive target stability assay, cellular thermal shift assay, and surface plasmon resonance analysis. SB-222200 effectively inhibits the activation of the NLRP3 inflammasome in macrophages, while having no impact on the activation of NLRC4 or AIM2 inflammasome. Furthermore, SB-222200 directly binds to the NLRP3 protein, inhibiting NLRP3 inflammasome assembly by blocking the NEK7 - NLRP3 interaction and NLRP3 oligomerization. Importantly, treatment with SB-222200 demonstrates alleviation of NLRP3-dependent inflammatory diseases in mouse models, such as monosodium urate crystal-induced peritonitis and dextran sulfate sodium-induced acute intestinal inflammation. Therefore, SB-222200 holds promise as a lead compound for the development of NLRP3 inhibitors to combat NLRP3-driven disease and serves as a versatile tool for pharmacologically investigating NLRP3 biology.
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Proteína con Dominio Pirina 3 de la Familia NLR , Peritonitis , Ratones , Animales , Humanos , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Inflamasomas/metabolismo , Peritonitis/inducido químicamente , Peritonitis/tratamiento farmacológico , Peritonitis/metabolismo , Macrófagos/metabolismo , Inflamación/metabolismo , Ratones Endogámicos C57BL , Interleucina-1beta/metabolismoRESUMEN
When exposed to high light, plants produce reactive oxygen species (ROS). In Arabidopsis thaliana, local stress such as excess heat or light initiates a systemic ROS wave in phloem and xylem cells dependent on NADPH oxidase/respiratory burst oxidase homolog (RBOH) proteins. In the case of excess light, although the initial local accumulation of ROS preferentially takes place in bundle-sheath strands, little is known about how this response takes place. Using rice and the ROS probes diaminobenzidine and 2',7'-dichlorodihydrofluorescein diacetate, we found that, after exposure to high light, ROS were produced more rapidly in bundle-sheath strands than mesophyll cells. This response was not affected either by CO2 supply or photorespiration. Consistent with these findings, deep sequencing of messenger RNA (mRNA) isolated from mesophyll or bundle-sheath strands indicated balanced accumulation of transcripts encoding all major components of the photosynthetic apparatus. However, transcripts encoding several isoforms of the superoxide/H2O2-producing enzyme NADPH oxidase were more abundant in bundle-sheath strands than mesophyll cells. ROS production in bundle-sheath strands was decreased in mutant alleles of the bundle-sheath strand preferential isoform of OsRBOHA and increased when it was overexpressed. Despite the plethora of pathways able to generate ROS in response to excess light, NADPH oxidase-mediated accumulation of ROS in the rice bundle-sheath strand was detected in etiolated leaves lacking chlorophyll. We conclude that photosynthesis is not necessary for the local ROS response to high light but is in part mediated by NADPH oxidase activity.
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Luz , NADPH Oxidasas/metabolismo , Oryza/enzimología , Oryza/efectos de la radiación , Fotosíntesis/efectos de la radiación , Haz Vascular de Plantas/enzimología , Haz Vascular de Plantas/fisiología , Especies Reactivas de Oxígeno/metabolismo , Bencidinas/metabolismo , Dióxido de Carbono/metabolismo , Regulación de la Expresión Génica de las Plantas , Oryza/genética , Oryza/fisiología , Oxígeno/metabolismo , Fotosíntesis/genética , Hojas de la Planta/genética , Hojas de la Planta/efectos de la radiación , Haz Vascular de Plantas/efectos de la radiación , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transcriptoma/genéticaRESUMEN
PURPOSE: Thoracic epidural anesthesia (TEA) is often used for analgesia after thoracic surgery. Erector spinae plane block (ESPB) has been proposed to provide adequate analgesia. We hypothesized that ESPB would be noninferior to TEA as a part of multimodal analgesia in pediatric patients undergoing the Nuss procedure. METHODS: Patients aged 7-18 years and scheduled for the Nuss procedure were randomly allocated to receive bilateral single-shot ESPB or TEA and a multimodal analgesic regimen including parent-controlled intravenous analgesia (PCIA). At 6 h, 12 h, 18 h, and 24 h postoperatively, pain was evaluated using the numeric rating scale (NRS) and opioid consumption was assessed by counting the number of PCIA boluses. The joint primary outcomes were the average pain score and opioid consumption at 24 h after surgery. The secondary outcomes were the NRS scores and the number of opioid boluses administered at different postoperative time points, adverse events, and recovery quality. RESULTS: Three hundred patients underwent randomization, and 286 received ESPB (147 patients) or TEA (139 patients). At 24 h postoperatively, ESPB was noninferior to TEA in terms of the average NRS score (mean difference, - 0.1, 95% confidence interval [CI], - 0.3-0.1, margin = 1, P for noninferiority < 0.001) and the number of opioid boluses administered (mean difference, - 1.1, 95% CI, - 2.8-0.6, margin = 7, P for noninferiority < 0.001). Adverse events and patient recovery were comparable between groups. CONCLUSIONS: The results demonstrate that combined with a multimodal analgesia, ESPB provides noninferior analgesia compared to TEA with respect to pain score and opioid consumption among pediatric patients undergoing the Nuss procedure.
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Metallo-supramolecular cages have garnered tremendous attention for their diverse yet molecular-level precision structures. However, physical properties of these supramolecular ensembles, which are of potential significance in molecular electronics, remain largely unexplored. We herein constructed a series of octahedral metallo-cages and cage-fullerene complexes with notably enhanced structural stability. As such, we could systematically evaluate the electrical conductivity of these ensembles at both single-molecule level and aggregated bulk state (as well-defined films). Our findings reveal that counteranions and fullerene guests play a pivotal role in determining the electrical conductivity of aggregated state, while such effects are less significant for single-molecule conductance. Both counteranions and fullerenes effectively tune the electronic structures and packing density of metallo-supramolecular assemblies, and facilitate efficient charge transfer between the cage hosts and fullerenes, resulting in a notable one order of magnitude increase in electrical conductivity of the aggregated state.
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Oils are hydrophobic, but their degradation is frequently found to be accelerated in the presence of water microdroplets. The direct chemical consequences of water-oil contact have long been overlooked. We show that aqueous microdroplets in emulsified water-hexadecane (C16H34) mixtures can spontaneously produce CO2, â¢H, H2, and short-chain hydrocarbons (mainly C1 and C2) as detected by gas chromatography, electron paramagnetic resonance spectroscopy, and mass spectrometry. This reaction results from contact electrification at the water-oil microdroplet interface, in which reactive oxygen species are produced, such as hydrated hydroxyl radicals and hydrogen peroxide. We also find that the H2 originates from the water microdroplet and not the hydrocarbon it contacts. These observations highlight the potential of interfacial contact electrification to produce new chemistry.
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AKR7A3 is a member of the aldo-keto reductase (AKR) protein family, whose primary purpose is to reduce aldehydes and ketones to generate primary and secondary alcohols. It has been reported that AKR7A3 is downregulated in pancreatic cancer (PC). However, the mechanism underlying the effects of AKR7A3 in PC remains largely unclarified. Here, we explored the biological function, molecular mechanism and clinical relevance of AKR7A3 in pancreatic ductal adenocarcinoma (PDAC). AKR7A3 expression was downregulated in PDAC compared with adjacent normal tissues, and the lower AKR7A3 expression was related to poor prognosis. In addition, our results demonstrated that AKR7A3 could be a potential diagnostic marker for PDAC, especially in the early stages. Knockdown of AKR7A3 promoted PDAC progression and chemoresistance, while inhibiting autophagy flux. Mechanistically, AKR7A3 affected the metastasis, autophagy, and chemoresistance of PDAC by regulating PHGDH. Overall, the present study suggests that AKR7A3 inhibits PDAC progression by regulating PHGDH-induced autophagy. In addition, AKR7A3 inhibits chemoresistance via regulating PHGDH and may serve as a new therapeutic target for PDAC.
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Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Pronóstico , Carcinoma Ductal Pancreático/patología , Neoplasias Pancreáticas/patología , Aldo-Ceto Reductasas/genética , Aldo-Ceto Reductasas/metabolismo , Autofagia/genética , Regulación Neoplásica de la Expresión Génica , Línea Celular Tumoral , Proliferación Celular/genética , Neoplasias PancreáticasRESUMEN
Venetoclax inhibits acute myeloid leukaemia by inhibiting BCL-2 targeting, and a combination regimen with venetoclax has been explored. Although these regimens produce better clinical results, the vast majority of patients still suffer from disease recurrence or primary drug resistance. Metformin has been demonstrated to induce apoptosis in cancer cells. However, whether it can synergize with venetoclax and the underlying mechanisms of metformin-induced apoptosis are not fully understood. In this study, we investigated the effect of metformin and venetoclax on the growth of AML cells in vitro and in vivo. In both Molm13 and THP-1 cell lines, metformin and venetoclax synergistically inhibited the proliferation and induced apoptosis of leukaemia cells. Most importantly, the combination of metformin and venetoclax treatment significantly increased the expression levels of the endoplasmic reticulum (ER) stress-related marker CHOP, for example, in AML cell lines. Knockdown of CHOP markedly attenuated the metformin- and venetoclax-induced cell apoptosis. Moreover, the combination of metformin and venetoclax demonstrated prominent anti-leukaemia effects in xenograft models and bone marrow samples from AML patients. In summary, the combination of metformin and venetoclax showed enhanced anti-leukaemia activity with acceptable safety in AML patients, representing a new combinatorial strategy worth further clinical investigation to treat AML.
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Leucemia Mieloide Aguda , Metformina , Humanos , Metformina/farmacología , Metformina/uso terapéutico , Línea Celular Tumoral , Recurrencia Local de Neoplasia , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2 , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Compuestos Bicíclicos Heterocíclicos con Puentes/uso terapéutico , Apoptosis , Estrés del Retículo EndoplásmicoRESUMEN
The ion conversion processes in CH2Cl2-enhanced vacuum ultraviolet photoionization of oxygenated volatile organic compounds (OVOCs) have been systematically studied by regulating the pressure, humidity, and reaction time in the ionization source of a time-of-flight mass spectrometer. As the ionization source pressure increased from 100 to 1100 Pa, the main characteristic ions changed from CH2Cl+ to CH2Cl+(H2O), CH2OH+, and C2H4OH+ and then to the hydrated hydronium ions H3O+(H2O)n (n = 1, 2, 3). The total ion current (TIC) almost remained unchanged even if the humidity increased from 44 to 3120 ppmv, indicating interconversion between ions through ion-molecule reactions. The intensity of protonated methanol/ethanol (sample S) ion was almost linearly correlated with the intensity of H3O+(H2O)n, which pointed to the proton transfer reaction (PTR) mechanism. The reaction time was regulated by the electric field strength in the ionization region. The intensity variation trends of different ions with the reaction time indicated that a series of step-by-step ion-molecule reactions occurred in the ionization source, i.e., the primary ion CH2Cl+ reacted with H2O and converted to the intermediate product ions CH2OH+ and C2H4OH+, which then further reacted with H2O and led to the production of H3O+, and finally, the protonated sample ion SH+ was obtained through PTR with H3O+, as the ion-molecule reactions progressed. This study provides valuable insights into understanding the formation mechanism of some unexpected intermediate product ions and hydrated hydronium ions in dopant-enhanced VUV photoionization and also helps to optimize experimental conditions to enhance the sensitivity of OVOCs.
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Hydrogen cyanide (HCN) is a well-known toxic compound in many fields. The trace amount of endogenous HCN in human exhalation has been associated with the presence of Pseudomonas aeruginosa (PA) infection in cystic fibrosis (CF) patients. Online monitoring of HCN profile is promising to screen PA infection rapidly and accurately. In this study, a gas flow-assisted negative photoionization (NPI) mass spectrometry method was developed for monitoring the single-exhalation HCN profile. The sensitivity could be optimized by introducing helium to eliminate the humidity influence and reduce the low mass cutoff effect, with improvements of a factor 150 observed. By employing a purging gas procedure and minimizing the length of the sample line, the residual and response time were greatly reduced. The limit of detection (LOD) of 0.3 ppbv and time resolution of 0.5 s were achieved. HCN profiles of exhalations from different volunteers before or after gargling with water were detected to show the performance of the method. All profiles showed a sharp peak and a stable end-tidal plateau, representing the concentration of oral cavity and end-tidal gas, respectively. The HCN concentration based on the plateau of the profile showed better reproducibility and accuracy, which indicates this method has potential application in the detection of PA infection in CF patients.
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Fibrosis Quística , Infecciones por Pseudomonas , Humanos , Espiración , Reproducibilidad de los Resultados , Pruebas Respiratorias/métodos , Infecciones por Pseudomonas/diagnóstico , Espectrometría de Masas/métodosRESUMEN
Ethyl carbamate (EC), a carcinogenic compound, is naturally produced in fermented foods and alcoholic beverages. Rapid and accurate measurement of EC is necessary and important for quality control and safety evaluation of Chinese liquor, a traditionally distilled spirit with the highest consumption in China, but it remains a great challenge. In this work, a direct injection mass spectrometry (DIMS) with time-resolved flash-thermal-vaporization (TRFTV) and acetone-assisted high-pressure photoionization (HPPI) strategy has been developed. EC was rapidly separated from the main matrix components, ethyl acetate (EA) and ethanol, by the TRFTV sampling strategy due to the retention time difference of these three compounds with large boiling point differences on the inner wall of a poly(tetrafluoroethylene) (PTFE) tube. Therefore, the matrix effect of EA and ethanol was effectively eliminated. The acetone-assisted HPPI source was developed for efficient ionization of EC through a photoionization-induced proton transfer reaction between EC molecules and protonated acetone ions. The accurate quantitative analysis of EC in liquor was achieved by introducing an internal standard method (ISM) using deuterated EC (d5-EC). As a result, the limit of detection (LOD) for EC was 8.88 µg/L with the analysis time of only 2 min, and the recoveries ranged from 92.3 to 113.1%. Finally, the prominent capability of the developed system was demonstrated by rapid determination of trace EC in Chinese liquors with different flavor types, exhibiting wide potential applications in online quality control and safety evaluation of not only Chinese liquors but also other liquor and alcoholic beverages.
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Increase in grain yield is always a major objective of wheat genetic improvement. The SQUAMOSA promoter-binding protein-like (SPL) genes, coding for a small family of diverse plant-specific transcription factors, represent important targets for improving grain yield and other major agronomic traits in rice. The function of the SPL genes in wheat remains to be investigated in this respect. In this study, we identified 56 wheat orthologues of rice SPL genes belonging to 19 homoeologous groups. Like in rice, nine orthologous TaSPL genes harbour the microRNA156 recognition elements (MRE) in their last exons except for TaSPL13, which harbour the MRE in its 3'-untranslated region (3'UTR). We modified the MRE of TaSPL13 using CRISPR-Cas9 and generated 12 mutations in the three homoeologous genes. As expected, the MRE mutations led to an approximately two-fold increase in the TaSPL13 mutant transcripts. The phenotypic evaluation showed that the MRE mutations in TaSPL13 resulted in a decrease in flowering time, tiller number, and plant height, and a concomitantly increase in grain size and number. The results show that the TaSPL13 mutants exhibit a combination of different phenotypes observed in Arabidopsis AtSPL3/4/5 mutants and rice OsSPL13/14/16 mutants and hold great potential in improving wheat yield by simultaneously increasing grain size and number and by refining plant architecture. The novel TaSPL13 mutations generated can be utilized in wheat breeding programmes to improve these agronomic traits.