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Study of the conformational and mechanical behaviors of biomolecular assemblies is vital to the rational design and realization of artificial molecular architectures with biologically relevant functionality. Here, we revealed DNA-modulated and mechanoresponsive excitonic couplings between organic chromophores and verified strong correlations between the excitonic chiroptical responses and the conformational and mechanical states of DNA self-assemblies irrespective of fluorescence background interference. Besides, the excitonic chiroptical effect allowed sensitive monitoring of DNA self-assembled nanostructures due to small molecule bindings or DNA strand displacement reactions. Moreover, we developed a new chiroptical reporter, a DNA-templated dimer of an achiral cyanine5 and an intrinsically chiral BODIPY, that exhibited unique multiple-split spectral line shape of exciton-coupled circular dichroism, largely separated response wavelengths, and enhanced anisotropy dissymmetry factor (g-factor). These results shed light on a promising chiroptical spectroscopic tool for studying biomolecular recognition and binding, conformation dynamics, and soft mechanics in general.
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Nanoestructuras , Nanoestructuras/química , ADN/química , Conformación Molecular , Dicroismo CircularRESUMEN
Astaxanthin is a high-value compound commercially synthesized through Xanthophyllomyces dendrorhous fermentation. Using mixed sugars decomposed from biowastes for yeast fermentation provides a promising option to improve process sustainability. However, little effort has been made to investigate the effects of multiple sugars on X. dendrorhous biomass growth and astaxanthin production. Furthermore, the construction of a high-fidelity model is challenging due to the system's variability, also known as batch-to-batch variation. Two innovations are proposed in this study to address these challenges. First, a kinetic model was developed to compare process kinetics between the single sugar (glucose) based and the mixed sugar (glucose and sucrose) based fermentation methods. Then, the kinetic model parameters were modeled themselves as Gaussian processes, a probabilistic machine learning technique, to improve the accuracy and robustness of model predictions. We conclude that although the presence of sucrose does not affect the biomass growth kinetics, it introduces a competitive inhibitory mechanism that enhances astaxanthin accumulation by inducing adverse environmental conditions such as osmotic gradients. Moreover, the hybrid model was able to greatly reduce model simulation error and was particularly robust to uncertainty propagation. This study suggests the advantage of mixed sugar-based fermentation and provides a novel approach for bioprocess dynamic modeling.
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Fermentación/fisiología , Modelos Biológicos , Saccharomyces cerevisiae/metabolismo , Biomasa , Reactores Biológicos/microbiología , Glucosa/metabolismo , Cinética , Ingeniería Metabólica , Incertidumbre , Xantófilas/análisis , Xantófilas/metabolismoRESUMEN
Paraquat (PQ) herbicide causes damage to green plant tissues by inducing the production of toxic reactive oxygen species (ROS). SUMOylation is an important post-translational modification that enables plants to defend against multiple stresses. However, it is still unknown whether the SUMOylation is involved in PQ resistance response in crops. Herein, we showed that a maize SUMO conjugating enzyme gene (ZmSCE1b) functioned in PQ resistance. The quantitative real-time PCR (qRT-PCR) analysis revealed that this gene was significantly up-regulated upon PQ exposure. The overexpression of ZmSCE1b increased the levels of SUMO conjugates and improved PQ resistance in transgenic Arabidopsis. The ZmSCE1b-transgenic plants showed lower levels of ROS and lipid peroxidation, as well as higher antioxidant enzyme activities, upon PQ exposure. Furthermore, Western blotting showed that levels of SUMOylation in these transgenic plants were significantly elevated. In addition, the abundance of transcripts of several defense-related genes was apparently up-regulated in the over-expressing lines using qRT-PCR. Collectively, our results manifested the effect of overexpression of ZmSCE1b in improving resistance to PQ, possibly by regulating the levels of SUMO conjugates, antioxidant machinery, and expression of defense genes. Findings of this study can facilitate the understanding of the regulatory mechanisms underlying the involvement of SCE-mediated SUMOylation in PQ resistance response in crop plants. Meanwhile, ZmSCE1b could be utilized for engineering PQ-resistant crops in phytoremediation.
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Herbicidas/toxicidad , Paraquat/toxicidad , Proteínas de Plantas/metabolismo , Sumoilación/fisiología , Zea mays/enzimología , Antioxidantes/metabolismo , Arabidopsis/metabolismo , Herbicidas/metabolismo , Peroxidación de Lípido , Plantas Modificadas Genéticamente/metabolismo , Sustancias Protectoras/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Regulación hacia Arriba , Zea mays/metabolismoRESUMEN
In this article, a new compound H2[{Cu(HL)(H2O)}2(P2Mo5O23)]·5H2O (1) (HLâ¯=â¯2-acetylpyrazine thiosemicarbazone) has been synthesized and structurally characterized by single-crystal X-ray diffraction of and other detection techniques. Interestingly, the structure of 1 is different from many reported copper-based complexes, in which the [P2Mo5O23]6-, two Cu2+ ions and two HL were directly connected by covalent bands. Biological studies demonstrated that 1 indicated moderate antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and a better cytotoxicity against human hepatic cancer line (SMMC-7721) than Mitoxantrone (Mito), the current clinical anticancer drug. Besides, the antibacterial mechanisms of 1 have been studied by the membrane integrity disruption, the destructive reactive oxygen species generation (ROS), the glutathione (GSH) depletion and the depressed enzymatic activity of respiratory chain dehydrogenases (RCD). These results revealed that the combination of HL, Cu2+, [P2Mo5O23]6- shows a higher antibacterial and cytotoxic activity.
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Cobre/química , Tiosemicarbazonas/síntesis química , Humanos , Estructura MolecularRESUMEN
Drought adversely affects crop growth and yields. The cloning and characterization of drought- or abscisic acid (ABA)-inducible promoters is of great significance for their utilization in the genetic improvement of crop resistance. Our previous studies have shown that maize sulfite oxidase (SO) has a sulfite-oxidizing function and is involved in the drought stress response. However, the promoter of the maize SO gene has not yet been characterized. In this study, the promoter (ZmSOPro, 1194 bp upstream region of the translation initiation site) was isolated from the maize genome. The in-silico analysis of the ZmSOPro promoter identified several cis-elements responsive to the phytohormone ABA and drought stress such as ABA-responsive element (ABRE) and MYB binding site (MBS), besides a number of core cis-acting elements, such as TATA-box and CAAT-box. A 5' RACE (rapid amplification of cDNA ends) assay identified an adenine residue as the transcription start site of the ZmSO. The ZmSOPro activity was detected by ß-glucuronidase (GUS) staining at nearly all developmental stages and in most plant organs, except for the roots in transgenic Arabidopsis. Moreover, its activity was significantly induced by ABA and drought stress. The 5'-deletion mutant analysis of the ZmSOPro in tobacco plants revealed that a 119-bp fragment in the ZmSOPro (upstream of the transcription start site) is a minimal region, which is required for its high-level expression. Moreover, the minimal ZmSOPro was significantly activated by ABA or drought stress in transgenic plants. Further mutant analysis indicated that the MBS element in the minimal ZmSOPro region (119 bp upstream of the transcription start site) is responsible for ABA and drought-stress induced expression. These results improve our understanding of the transcriptional regulation mechanism of the ZmSO gene, and the characterized 119-bp promoter fragment could be an ideal candidate for drought-tolerant gene engineering in both monocot and dicot crops.
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Ácido Abscísico/farmacología , Sequías , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Regiones Promotoras Genéticas , Sulfito-Oxidasa/genética , Zea mays/enzimología , Arabidopsis/genética , Emparejamiento Base/genética , Secuencia de Bases , Fluorescencia , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Glucuronidasa/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Estrés Fisiológico/efectos de los fármacos , Sulfito-Oxidasa/metabolismo , Zea mays/genéticaRESUMEN
Non-small cell lung cancer (NSCLC) is an aggressive malignancy with increasing worldwide incidence and is characterized by dismal prognosis due to its early recurrence and metastasis. Accumulating evidence documented that aberrantly expressed circular RNAs (circRNAs) are critically involved in tumorigenesis. In the current study, we focused on a novel circRNA, circ_0016760 in NSCLC. qRT-PCR was carried out to determine the expression level of circ_0016760 in tissue samples and cell lines. The clinical value of circ_0016760 was also investigated. The functions of circ_0016760 was explored by CCK-8, colony formation, flow cytometry, Transwell and animal experiments. Luciferase reporter assays were conducted to investigate the association between circ_0016760 and miR-1287 and miR-1287 and GAGE1. We found that circ_0016760 was enhanced in NSCLC tissues and cells and the upregulation of circ_0016760 is associated with advanced TNM stages, lymph node metastasis and adverse prognosis in NSCLC patients. Moreover, circ_0016760 could significantly promote cell growth and metastatic properties and inhibit cell apoptosis in NSCLC cells. In mechanism, circ_0016760 functioned as a sponge for miR-1287 and regulated the expression of GAGE1. Subsequently, functional assays illustrated that the oncogenic properties of circ_0016760 is partly attribute to the regulation of miR-1287/GAGE1 axis. In summary, circ_0016760/miR-1287/GAGE1 signaling might play vital roles in the tumorigenesis and progression of NSCLC.
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Antígenos de Neoplasias/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Neoplasias Pulmonares/metabolismo , MicroARNs/metabolismo , Proteínas de Neoplasias/metabolismo , ARN/metabolismo , Regulación hacia Arriba , Animales , Antígenos de Neoplasias/genética , Apoptosis , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico , Línea Celular , Movimiento Celular , Proliferación Celular , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , MicroARNs/genética , Persona de Mediana Edad , Proteínas de Neoplasias/genética , Neoplasias Experimentales/diagnóstico , Neoplasias Experimentales/metabolismo , Pronóstico , ARN/genética , ARN CircularRESUMEN
The heart rate (HR) measurements based on the camera (visible light) can be used to detect HR in non-contact mode, which has great application prospects both in the clinical application and home health care. However, CMOS sensors equipped with "rolling shutters", which distinguishes different lines per frame to become light sensitive at different moments in time, and stylized dithering of image acquisition (IMAQ) time caused by different computer programs running in the background will greatly influence the accuracy of the measured HR. In this paper, we analyze the phase error caused by CMOS sensor and the system error introduced by system sampling clock jitters. According to derivation, we propose two methods, amplitude-frequency superposition and a cubic spline interpolation reconstruction method based on actual schedules, that can be widely utilized in computer vision to overcome the camera phase error and sampling time fluctuation error. Amplitude of signal is analyzed and processed in amplitude-frequency domain in the method of amplitude-frequency superposition, which ignores the signal phase. Thus it can eliminate the phase error effectively. The cubic spline interpolation reconstruction method based on actual schedules can reconstructed the non-uniform sampling of images as uniform ones, so it can eliminate the system error involved by the system clock jitters. What's more, the properties of the methods are tested by applying them to both simulation experiments and real HR measurements. In the simulation, amplitude of measured signal is improved 4.58% relative to the amplitude measured without the method of amplitude-frequency superposition; root mean square error of signal's frequency, detected by the cubic spline interpolation reconstruction method based on actual schedules, is reduced more than 30%. In the real HR measurements, the amplitude of HR is raised to 33.5% relatively based on amplitude-frequency superposition. And the accuracy of HR is raised to approximately 40% by the method of cubic spline interpolation reconstruction method based on actual schedules. Therefore, the simulation experiments and real HR measurement proof that we can effectively eliminate the camera phase error based on the amplitude-frequency superposition extraction method, and the cubic spline interpolation based on the timetable method can effectively reduce the random error in IMAQ due to system clock jitters. These methods can both be widely used in dynamic signal detection based on machine vision.
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Algoritmos , Frecuencia CardíacaRESUMEN
The booming three-dimensional laser scanning technology can efficiently and effectively get spatial three-dimensional coordinates of the detected object surface and reconstruct the image at high speed,high precision and large capacity of information.Non-radiation,non-contact and the ability of visualization make it increasingly popular in three-dimensional surface medical mapping.This paper reviews the applications and developments of three-dimensional laser scanning technology in medical field,especially in stomatology,plastic surgery and orthopedics.Furthermore,the paper also discusses the application prospects in the future as well as the biomedical engineering problems it would encounter with.
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Diagnóstico por Imagen , Imagenología Tridimensional , Rayos Láser , HumanosRESUMEN
Along with the development of computer technologies and digitization of human body's information, the digital human entered into a new stage of modelling physical features from the stage of reconstructing anatomical structures. By summarizing domestic and abroad relevant documents, we in this paper present the general scheme of digital human and the location of physical human as well as its conception and applied value. We especially analyze the modeling process of physical human, core technologies and its research and applications in four main fields: electromagnetic radiation, ultrasound propagation, bioimpedance measurements and biomechanical analysis. We also analyze and summarize existing problems of present physical human model and point out the future development trends of physical human.
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Modelos Anatómicos , Fenómenos Biomecánicos , Impedancia Eléctrica , Fenómenos Electromagnéticos , Humanos , Programas Informáticos , UltrasonidoRESUMEN
Plantar pressure distribution can reflect the force of several key points on foot while standing and walking. A comprehensive understanding of the plantar pressure distribution makes great sense in the following aspects: the understanding of the normal foot biomechanics and function, clinical diagnosis, measurement of disease extent, postoperative efficacy evaluation, and rehabilitation research. A simple plantar pressure measurement device was designed in this study. This paper uses FlexiForce flexible sensor to pickup plantar pressure signal and USB A/D board to do data acquisition. The data are transferred into a laptop and processed by a VB-based software which can display, remember and replay the data. We chose patients with hallux valgus and normal people to measure the pressure distribution and make contrast analysis of plantar pressure with this device. It can be concluded that people with hallux valgus have higher pressure on the second metatarsophalangeal joint and the distribution move outward. The plantar pressure of patients postoperative could be greatly improved compared to the preoperative. The function of this device has been confirmed.
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Pie/fisiología , Monitoreo Fisiológico/instrumentación , Presión , Hallux Valgus/fisiopatología , Humanos , Articulación Metatarsofalángica/fisiopatología , CaminataRESUMEN
OBJECTIVES: Tenecteplase, a modified variant of alteplase with greater fibrin specificity and longer plasma half-life, may have better efficacy and safety than alteplase in patients with acute ischemic stroke (AIS). We aimed to compare the benefits and risks of tenecteplase versus alteplase in the treatment of AIS. METHODS: Electronic databases were searched up to 10 February 2023 for randomized controlled trials evaluating the effect of tenecteplase versus alteplase in the treatment of AIS. The primary outcome was functional outcome at 90 days, and secondary outcomes including the symptomatic intracranial haemorrhage (SICH), and major neurological improvement. Subgroup analysis was performed based on the different dosage of tenecteplase. RESULTS: Ten studies with a total of 5123 patients were analysed in this meta-analysis. Overall, no significant difference between tenecteplase and alteplase was observed for functional outcome at 90 days (excellent: OR 1.08, 95%CI 0.93-1.26, I2 = 26%; good: OR 1.04, 95%CI 0.83-1.30, I2 = 56%; poor: OR 0.95, 95%CI 0.75-1.21, I2 = 31%), SICH (OR 1.12, 95%CI 0.79-1.59, I2 = 0%), and early major neurological improvement (OR 1.26, 95%CI 0.80-1.96, I2 = 65%). The subgroup analysis suggested that the 0.25 mg/kg dose of tenecteplase had potentially greater efficacy and lower symptomatic intracerebral haemorrhage risk compared with 0.25 mg/kg dose tenecteplase. CONCLUSIONS: Among AIS patients, there was no significant difference on clinical outcomes between tenecteplase and alteplase. Subgroup analysis demonstrated that 0.25 mg/kg doses of tenecteplase were more beneficial than 0.4 mg/kg doses of tenecteplase. Further studies are required to identify the optimal dosage of tenecteplase.
Randomized controlled trials exploring comparative efficacy and safety of tenecteplase and alteplase have been yielding inconsistent results on various outcomes and merit the conduction of a meta-analysis to adequately answer these questions.Analysis of evidence from randomized studies suggests that tenecteplase is as safe as alteplase for the treatment of acute ischemic stroke and tenecteplase is potentially associated with more favourable outcomes.Tenecteplase at 0.25 mg/kg dose is more efficacious and at least as safe as alteplase for stroke thrombolysis.
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Accidente Cerebrovascular Isquémico , Activador de Tejido Plasminógeno , Humanos , Activador de Tejido Plasminógeno/efectos adversos , Tenecteplasa/efectos adversos , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Ensayos Clínicos Controlados Aleatorios como Asunto , Hemorragia CerebralRESUMEN
Acute myocardial infarction (MI) is a common and severe cardiovascular emergency that requires immediate treatment. Angina pectoris, which typically signals myocardial ischaemia, can appear in MI cases with myriad causes aside from coronary artery disease. However, not all MI patients benefit from invasive revascularisation therapy. We herein report a case involving a 78-year-old female patient with a complex medical history, including non-ST-segment elevation MI and coronary artery bypass grafting, who experienced recurrent chest pain. Instead of a direct result of coronary artery disease, her chest pain was later found to be primarily induced by atrial fibrillation (AF). Consequently, we shifted the focus of management to effective rate control for the AF after careful evaluation and achieved a satisfactory result. This case highlights the successful identification and timely application of intensive heart rate control management in an MI case induced by AF.
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Fibrilación Atrial , Insuficiencia Cardíaca , Infarto del Miocardio , Humanos , Anciano , Femenino , Fibrilación Atrial/terapia , Fibrilación Atrial/complicaciones , Infarto del Miocardio/complicaciones , Infarto del Miocardio/terapia , Insuficiencia Cardíaca/etiología , Revascularización Miocárdica/métodos , Antiarrítmicos/uso terapéutico , Frecuencia Cardíaca/fisiologíaRESUMEN
Vigilance is defined as the ability to maintain attention or alertness over prolonged periods of time. Since Mid-20th century, following the increasing man-machine communication, high level of vigilance has been demanded in many areas including driving safety, medical care and therapy, aerospace and military affairs, etc. Therefore, finding quick methods to improve the level of vigilance has become a key issue in medical study. Based on physical regulation, chemical regulation and physiological regulation, the research progress has been summarized in this paper. We, furthermore, also try to predict the future trend in this academic area and develop some tentative ideas about seeking more effective and convenient ways to improve the level of brain vigilance.
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Nivel de Alerta/fisiología , Atención , Encéfalo/fisiología , Descanso/fisiología , Café , Humanos , Luz , SonidoRESUMEN
Purpose: Delirium is common during critical illness and is associated with poor outcomes. Therefore, we conducted this meta-analysis to investigate the efficacy and safety of haloperidol for the treatment of delirium in critically ill patients. Methods: Randomized controlled trials enrolling critically ill adult patients to compare haloperidol with placebo were searched from inception through to February 20th, 2023. The primary outcome were delirium-free days and overall mortality, secondary outcomes were length of intensive care unit stay, length of hospital stay, and adverse events. Results: Nine trials were included in our meta-analysis, with a total of 3,916 critically ill patients. Overall, the pooled analyses showed no significant difference between critically ill patients treated with haloperidol and placebo for the delirium-free days (MD -0.01, 95%CI -0.36 to 0.34, p = 0.95, I2 = 30%), overall mortality (OR 0.89, 95%CI 0.76 to 1.04, p = 0.14, I2 = 0%), length of intensive care unit stay (MD -0.06, 95%CI -0.16 to 0.03, p = 0.19, I2 = 0%), length of hospital stay (MD -0.06, 95%CI -0.61 to 0.49, p = 0.83, I2 = 0%), and adverse events (OR 0.90, 95%CI 0.60 to 1.37, p = 0.63, I2 = 0%). Conclusion: Among critically ill patients, the use of haloperidol as compared to placebo has no significant effect on delirium-free days, overall mortality, length of intensive care unit and/or hospital stay. Moreover, the use of haloperidol did not increase the risk of adverse events.
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Rational design and modification of autotrophic bacteria to efficiently produce high-value chemicals and biofuels are crucial for establishing a sustainable and economically viable process for one-carbon (C1) source utilization, which, however, remains a challenge in metabolic engineering. In this study, autotrophic Clostridium ljungdahlii was metabolically engineered to efficiently co-produce three important bulk chemicals, isopropanol, 3-hydroxybutyrate (3-HB), and ethanol (together, IHE), using syngas (CO2/CO). An artificial isopropanol-producing pathway was first constructed and optimized in C. ljungdahlii to achieve an efficient production of isopropanol and an unexpected product, 3-HB. Based on this finding, an endogenous active dehydrogenase capable of converting acetoacetate to 3-HB was identified in C. ljungdahlii, thereby revealing an efficient 3-HB-producing pathway. The engineered strain was further optimized to reassimilate acetic acid and synthesize 3-HB by introducing heterologous functional genes. Finally, the best-performing strain was able to produce 13.4, 3.0, and 28.4 g/L of isopropanol, 3-HB, and ethanol, respectively, in continuous gas fermentation. Therefore, this work represents remarkable progress in microbial production of bulk chemicals using C1 gases.
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2-Propanol/metabolismo , Ácido 3-Hidroxibutírico/metabolismo , Dióxido de Carbono/metabolismo , Monóxido de Carbono/metabolismo , Clostridium/metabolismo , Etanol/metabolismo , Fermentación , Ingeniería MetabólicaRESUMEN
This study aims to develop an artificial intelligence (AI)-based model to assist radiologists in pneumoconiosis screening and staging using chest radiographs. The model, based on chest radiographs, was developed using a training cohort and validated using an independent test cohort. Every image in the training and test datasets were labeled by experienced radiologists in a double-blinded fashion. The computational model started by segmenting the lung field into six subregions. Then, convolutional neural network classification model was used to predict the opacity level for each subregion respectively. Finally, the diagnosis for each subject (normal, stage I, II, or III pneumoconiosis) was determined by summarizing the subregion-based prediction results. For the independent test cohort, pneumoconiosis screening accuracy was 0.973, with both sensitivity and specificity greater than 0.97. The accuracy for pneumoconiosis staging was 0.927, better than that achieved by two groups of radiologists (0.87 and 0.84, respectively). This study develops a deep learning-based model for screening and staging of pneumoconiosis using man-annotated chest radiographs. The model outperformed two groups of radiologists in the accuracy of pneumoconiosis staging. This pioneer work demonstrates the feasibility and efficiency of AI-assisted radiography screening and diagnosis in occupational lung diseases.
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Aprendizaje Profundo , Tamizaje Masivo , Modelos Biológicos , Neumoconiosis/diagnóstico , Bases de Datos como Asunto , Humanos , Neumoconiosis/diagnóstico por imagen , Neumoconiosis/patología , Radiólogos , Reproducibilidad de los ResultadosRESUMEN
Liquid level detection (LLD) is necessary for eliminating carry-over of needle's outside by limiting the depth the needle probes into liquid in auto clinical laboratory analyzers. This paper listed various demands of liquid-handling system under different situations; reviewed various LLD techniques, such as capacitive, air pressure, mechanical vibration, ultrasound, light reflection, CCD imaging etc.; briefly introduced the working principles, features, and limitation of the LLDs; and recapitulated the characteristics of contact and non-contact LLDs. Lastly, the next generation technique of LLD is prospected.
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Automatización , Técnicas de Laboratorio Clínico/instrumentación , Técnicas de Laboratorio Clínico/métodosRESUMEN
Carotenoids are a group of natural tetraterpenoid pigments with essential roles in a variety of physiological processes of plants. Although carotenoid biosynthesis has been well characterized, the genetic basis of the pathway, especially in crop plants, is largely unknown. In this study, we characterized a new albino maize mutant called albino1 (alb1), which was obtained from a Mutator mutagenized population. The alb1 mutant showed defective chloroplast development and declined photosynthetic pigments, leading to a seedling-lethal phenotype. Genetic and molecular analyses indicated that ALB1 encoded a putative ζ-carotene desaturase (ZDS) involved in carotenoid biosynthesis. Measurement of carotenoids revealed that several major carotenoid compounds downstream of the ZDS were significantly reduced in alb1 mutant, indicating that ALB1 is a functional ZDS. Further transcriptome analysis revealed that several groups of nuclear genes involved in photosynthesis, such as light-harvesting complex, pigment metabolism, and chloroplast function, were significantly down-regulated in alb1 compared with wide type. Interestingly, expression of some maize plastid-localized nuclear genes, including POR, CAO, Lhcb, and RbcS, was substantially reduced in alb1 plants. Furthermore, treatment of the inhibitor fluridone significantly rescued gene transcripts of these nucleus-encoded genes in alb1 mutant, which supported the retrograde signaling of ζ-carotene/phytofluene derived molecules. These results suggested that ALB1/ZDS might function as a regulator to coordinate nuclear photosynthetic gene expression in plastid-to-nucleus retrograde signaling during development of maize plants. Together, these results have demonstrated that ALB1/ZDS is essential for carotenoids biosynthesis and plays crucial roles in chloroplast biogenesis and development in maize.
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Cloroplastos/enzimología , Oxidorreductasas/fisiología , Proteínas de Plantas/fisiología , Zea mays/enzimología , Carotenoides/metabolismo , Cloroplastos/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Oxidorreductasas/genética , Proteínas de Plantas/genética , Zea mays/genéticaRESUMEN
CRISPRs are a promising tool being explored in combating exogenous retroviral pathogens and in disabling endogenous retroviruses for organ transplantation. The Cas12a and Cas13a systems offer novel mechanisms of CRISPR actions that have not been evaluated for retrovirus interference. Particularly, a latest study revealed that the activated Cas13a provided bacterial hosts with a "passive protection" mechanism to defend against DNA phage infection by inducing cell growth arrest in infected cells, which is especially significant as it endows Cas13a, a RNA-targeting CRISPR effector, with mount defense against both RNA and DNA invaders. Here, by refitting long terminal repeat retrotransposon Tf1 as a model system, which shares common features with retrovirus regarding their replication mechanism and life cycle, we repurposed CRISPR-Cas12a and -Cas13a to interfere with Tf1 retrotransposition, and evaluated their different mechanisms of action. Cas12a exhibited strong inhibition on retrotransposition, allowing marginal Tf1 transposition that was likely the result of a lasting pool of Tf1 RNA/cDNA intermediates protected within virus-like particles. The residual activities, however, were completely eliminated with new constructs for persistent crRNA targeting. On the other hand, targeting Cas13a to Tf1 RNA intermediates significantly inhibited Tf1 retrotransposition. However, unlike in bacterial hosts, the sustained activation of Cas13a by Tf1 transcripts did not cause cell growth arrest in S. pombe, indicating that virus-activated Cas13a likely acted differently in eukaryotic cells. The study gained insight into the actions of novel CRISPR mechanisms in combating retroviral pathogens, and established system parameters for developing new strategies in treatment of retrovirus-related diseases.
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Drought is one of the major environmental stresses limiting crop growth and production. It is very important to exploit and utilize drought-tolerance genes to improve crop drought-resistance. In this study, we identified two homoeologs of a Nicotiana tabacum (Ntab) DELAY OF GERMINATION (DOG) 1 like gene, named as NtabDOG1L-T and NtabDOG1L-S, respectively. The NtabDOG1L genes were preferentially expressed in roots and their expression levels were induced by polyethylene glycol, high salt, cold, and abscisic acid treatments. Subcellular localization results indicated that NtabDOG1L-T was localized in the nucleus, cytoplasm and cell membrane. Overexpression of NtabDOG1L-T in tobacco resulted in roots growth enhancement in transgenic plants. Furthermore, overexpression of NtabDOG1L-T enhanced drought stress tolerance in transgenic tobacco. The transgenic tobacco lines exhibited lower leaf water loss and electrolyte leakage, lower content of malondialdehyde and reactive oxygen species (ROS), and higher antioxidant enzymes activities after drought treatment when compared with wild type (WT) plants. In addition, the expression levels of several genes encoding key antioxidant enzymes and drought-related proteins were higher in the transgenic plants than in the WT plants under drought stress. Taken together, our results showed that NtabDOG1L functions as a novel regulator that improves plant growth and drought tolerance in tobacco.