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1.
Cell ; 186(20): 4454-4471.e19, 2023 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-37703875

RESUMEN

Macrophages are heterogeneous and play critical roles in development and disease, but their diversity, function, and specification remain inadequately understood during human development. We generated a single-cell RNA sequencing map of the dynamics of human macrophage specification from PCW 4-26 across 19 tissues. We identified a microglia-like population and a proangiogenic population in 15 macrophage subtypes. Microglia-like cells, molecularly and morphologically similar to microglia in the CNS, are present in the fetal epidermis, testicle, and heart. They are the major immune population in the early epidermis, exhibit a polarized distribution along the dorsal-lateral-ventral axis, and interact with neural crest cells, modulating their differentiation along the melanocyte lineage. Through spatial and differentiation trajectory analysis, we also showed that proangiogenic macrophages are perivascular across fetal organs and likely yolk-sac-derived as microglia. Our study provides a comprehensive map of the heterogeneity and developmental dynamics of human macrophages and unravels their diverse functions during development.


Asunto(s)
Macrófagos , Humanos , Diferenciación Celular , Linaje de la Célula , Macrófagos/citología , Microglía , Especificidad de Órganos
2.
Crit Rev Immunol ; 44(3): 1-12, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38421701

RESUMEN

Endothelial dysfunction is associated with the progression of sepsis. This study sought to probe the molecular route of sex-determining region on the Y chromosome-box transcription factor 18 (SOX18) in sepsis-associated endothelial injury. Human umbilical vein endothelial cells (HUVECs) were treated with lipopolysaccharide (LPS) to establish the sepsis cell model. Cell viability, lactate dehydrogenase (LDH) release, oxidative stress (reactive oxygen species/malondialdehyde/superoxide dismutase), and inflammation (interleukin-1ß/tumor necrosis factor-α/interleukin-6) were evaluated by cell counting kit-8 assay and relevant assay kits. The expression levels of SOX18, microRNA (miR)-204-5p, and cadherin-2 (CDH2) in cells were determined by real-time quantitative polymerase chain reaction and Western blot assay. The interaction of SOX18, miR-204-5p, and CDH2 was analyzed by chromatin immunoprecipitation and dual-luciferase assay. LPS induced HUVECs injury and downregulation of SOX18. SOX18 overexpression increased cell viability, while decreased LDH activity, oxidative stress, and inflammation. SOX18 bound to the miR-204-5p promoter to promote miR-204-5p expression, and further repressed CDH2 expression. miR-204-5p knockdown and CDH2 overexpression abrogated the protective role of SOX18 in HUVECs injury. Overall, SOX18 alleviated LPS-induced injury of HUVECs by promoting miR-204-5p and repressing CDH2, suggesting it as a potential target for sepsis treatment.


Asunto(s)
MicroARNs , Sepsis , Humanos , Células Endoteliales de la Vena Umbilical Humana , Lipopolisacáridos , Inflamación , MicroARNs/genética , Factores de Transcripción SOXF/genética
3.
Metab Eng ; 83: 150-159, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38621518

RESUMEN

Microbial CO2 fixation into lactic acid (LA) is an important approach for low-carbon biomanufacturing. Engineering microbes to utilize CO2 and sugar as co-substrates can create efficient pathways through input of moderate reducing power to drive CO2 fixation into product. However, to achieve complete conservation of organic carbon, how to engineer the CO2-fixing modules compatible with native central metabolism and merge the processes for improving bioproduction of LA is a big challenge. In this study, we designed and constructed a solar formic acid/pentose (SFAP) pathway in Escherichia coli, which enabled CO2 fixation merging into sugar catabolism to produce LA. In the SFAP pathway, adequate reducing equivalents from formate oxidation drive glucose metabolism shifting from glycolysis to the pentose phosphate pathway. The Rubisco-based CO2 fixation and sequential reduction of C3 intermediates are conducted to produce LA stoichiometrically. CO2 fixation theoretically can bring a 20% increase of LA production compared with sole glucose feedstock. This SFAP pathway in the integration of photoelectrochemical cell and an engineered Escherichia coli opens an efficient way for fixing CO2 into value-added bioproducts.


Asunto(s)
Escherichia coli , Formiatos , Ácido Láctico , Ingeniería Metabólica , Escherichia coli/metabolismo , Escherichia coli/genética , Formiatos/metabolismo , Ácido Láctico/metabolismo , Ácido Láctico/biosíntesis , Dióxido de Carbono/metabolismo
4.
Crit Rev Biotechnol ; 44(3): 414-428, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-36842999

RESUMEN

Carbon neutrality by 2050 has become one of the most urgent challenges the world faces today. To address the issue, it is necessary to develop and promote new technologies related with CO2 recycling. Cyanobacteria are the only prokaryotes performing oxygenic photosynthesis, capable of fixing CO2 into biomass under sunlight and serving as one of the most important primary producers on earth. Notably, recent progress on synthetic biology has led to utilizing model cyanobacteria such as Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 as chassis for "light-driven autotrophic cell factories" to produce several dozens of biofuels and various fine chemicals directly from CO2. However, due to the slow growth rate and low biomass accumulation in the current chassis, the productivity for most products is still lower than the threshold necessary for large-scale commercial application, raising the importance of developing high-efficiency cyanobacterial chassis with fast growth and/or higher biomass accumulation capabilities. In this article, we critically reviewed recent progresses on identification, systems biology analysis, and engineering of fast-growing cyanobacterial chassis. Specifically, fast-growing cyanobacteria identified in recent years, such as S. elongatus UTEX 2973, S. elongatus PCC 11801, S. elongatus PCC 11802 and Synechococcus sp. PCC 11901 was comparatively analyzed. In addition, the progresses on their recent application in converting CO2 into chemicals, and genetic toolboxes developed for these new cyanobacterial chassis were discussed. Finally, the article provides insights into future challenges and perspectives on the synthetic biology application of cyanobacterial chassis.


Asunto(s)
Dióxido de Carbono , Biología Sintética , Fotosíntesis , Biocombustibles
5.
BMC Infect Dis ; 24(1): 200, 2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38355468

RESUMEN

BACKGROUND: A lack of health resources is a common problem after the outbreak of infectious diseases, and resource optimization is an important means to solve the lack of prevention and control capacity caused by resource constraints. This study systematically evaluated the similarities and differences in the application of coronavirus disease (COVID-19) resource allocation models and analyzed the effects of different optimal resource allocations on epidemic control. METHODS: A systematic literature search was conducted of CNKI, WanFang, VIP, CBD, PubMed, Web of Science, Scopus and Embase for articles published from January 1, 2019, through November 23, 2023. Two reviewers independently evaluated the quality of the included studies, extracted and cross-checked the data. Moreover, publication bias and sensitivity analysis were evaluated. RESULTS: A total of 22 articles were included for systematic review; in the application of optimal allocation models, 59.09% of the studies used propagation dynamics models to simulate the allocation of various resources, and some scholars also used mathematical optimization functions (36.36%) and machine learning algorithms (31.82%) to solve the problem of resource allocation; the results of the systematic review show that differential equation modeling was more considered when testing resources optimization, the optimization function or machine learning algorithm were mostly used to optimize the bed resources; the meta-analysis results showed that the epidemic trend was obviously effectively controlled through the optimal allocation of resources, and the average control efficiency was 0.38(95%CI 0.25-0.51); Subgroup analysis revealed that the average control efficiency from high to low was health specialists 0.48(95%CI 0.37-0.59), vaccines 0.47(95%CI 0.11-0.82), testing 0.38(95%CI 0.19-0.57), personal protective equipment (PPE) 0.38(95%CI 0.06-0.70), beds 0.34(95%CI 0.14-0.53), medicines and equipment for treatment 0.32(95%CI 0.12-0.51); Funnel plots and Egger's test showed no publication bias, and sensitivity analysis suggested robust results. CONCLUSION: When the data are insufficient and the simulation time is short, the researchers mostly use the constructor for research; When the data are relatively sufficient and the simulation time is long, researchers choose differential equations or machine learning algorithms for research. In addition, our study showed that control efficiency is an important indicator to evaluate the effectiveness of epidemic prevention and control. Through the optimization of medical staff and vaccine allocation, greater prevention and control effects can be achieved.


Asunto(s)
COVID-19 , Epidemias , Humanos , COVID-19/epidemiología , Equipo de Protección Personal , SARS-CoV-2 , Brotes de Enfermedades
6.
Appl Microbiol Biotechnol ; 108(1): 115, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38204133

RESUMEN

Cyanobacteria are excellent autotrophic photosynthetic chassis employed in synthetic biology, and previous studies have suggested that they have alkaline tolerance but low acid tolerance, significantly limiting their productivity as photosynthetic chassis and necessitating investigations into the acid stress resistance mechanism. In this study, differentially expressed genes were obtained by RNA sequencing-based comparative transcriptomic analysis under long-term acidic stress conditions and acidic shock treatment, in the model cyanobacterium Synechococcus elongatus PCC 7942. A pathway enrichment analysis revealed the upregulated and downregulated pathways during long-term acidic and shock stress treatment. The subsequent single gene knockout and phenotype analysis showed that under acidic stress conditions, the strains with chlL, chlN, pex, synpcc7942_2038, synpcc7942_1890, or synpcc7942_2547 knocked out grew worse than the wild type, suggesting their involvement in acid tolerance. This finding was further confirmed by introducing the corresponding genes back into the knockout mutant individually. Moreover, individual overexpression of the chlL and chlN genes in the wild type successfully improved the tolerance of S. elongatus PCC 7942 to acidic stress. This work successfully identified six genes involved in acidic stress responses, and overexpressing chIL or chIN individually successfully improved acid tolerance in S. elongatus PCC 7942, providing valuable information to better understand the acid resistance mechanism in S. elongatus PCC 7942 and novel insights into the robustness and tolerance engineering of cyanobacterial chassis. KEY POINTS: • DEGs were identified by RNA-seq based transcriptomics analysis in response to acidic stress in S. elongatus PCC 7942. • Six genes were identified to be involved in acid tolerance in S. elongatus PCC 7942. • Overexpression of chIL or chIN individually successfully improved the acid tolerance of S. elongatus PCC 7942.


Asunto(s)
Synechococcus , Expresión Génica , Perfilación de la Expresión Génica , Synechococcus/genética
7.
Mar Drugs ; 22(5)2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38786607

RESUMEN

Microalgal lipids hold significant potential for the production of biodiesel and dietary supplements. To enhance their cost-effectiveness and commercial competitiveness, it is imperative to improve microalgal lipid productivity. Metabolic engineering that targets the key enzymes of the fatty acid synthesis pathway, along with transcription factor engineering, are effective strategies for improving lipid productivity in microalgae. This review provides a summary of the advancements made in the past 5 years in engineering the fatty acid biosynthetic pathway in eukaryotic microalgae. Furthermore, this review offers insights into transcriptional regulatory mechanisms and transcription factor engineering aimed at enhancing lipid production in eukaryotic microalgae. Finally, the review discusses the challenges and future perspectives associated with utilizing microalgae for the efficient production of lipids.


Asunto(s)
Ácidos Grasos , Ingeniería Metabólica , Microalgas , Microalgas/metabolismo , Ingeniería Metabólica/métodos , Ácidos Grasos/biosíntesis , Ácidos Grasos/metabolismo , Biocombustibles , Vías Biosintéticas , Factores de Transcripción/metabolismo , Animales , Humanos
8.
Environ Res ; 223: 115428, 2023 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-36746205

RESUMEN

The over proliferation of harmful cyanobacteria and their cyanotoxins resulted in damaged aquatic ecosystem, polluted drinking water and threatened human health. Cyanophages are a kind of viruses that exclusively infect cyanobacteria, which is considered as a potential strategy to deal with cyanobacterial blooms. Nevertheless, the infecting host range and/or lysis efficiency of natural cyanophages is limited, rising the necessity of constructing non-natural cyanophages via artificial modification, design and synthesis to expand their host range and/or efficiency. The paper firstly reviewed representative cyanophages such as P60 with a short latent period of 1.5 h and S-CBS1 having a burst size up to 200 PFU/cell. To explore the in-silico design principles, we critically summarized the interactions between cyanophages and the hosts, indicating modifying the recognized receptors, enhancing the adsorption ability, changing the lysogeny and excluding the defense of hosts are important for artificial cyanophages. The research progress of synthesizing artificial cyanophages were summarized subsequently, raising the importance of developing genetic manipulation technologies and their rescue strategies in the future. Meanwhile, Large-scale preparation of cyanophages for bloom control is a big challenge. The application prospects of artificial cyanophages besides cyanobacteria bloom control like adaptive evolution and phage therapy were discussed at last. The review will promote the design, synthesis and application of cyanophages for cyanobacteria blooms, which may provide new insights for the related water pollution control and ensuring hydrosphere security.


Asunto(s)
Bacteriófagos , Cianobacterias , Humanos , Bacteriófagos/genética , Ecosistema
9.
Ann Noninvasive Electrocardiol ; 28(3): e13039, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36735381

RESUMEN

Gadopentetate dimeglumine (Gd-DTPA) is commonly used for enhancement in magnetic resonance imaging, but rarely causes serious adverse reactions. The patient presented in this report had a cardiac arrest and multiple organ dysfunction syndrome within a short time after administration of Gd-DTPA. Immediately after receiving an intravenous injection of Gd-DTPA, the patient felt nausea and chest tightness, and developed systemic erythema. He was successfully treated using veno-arterial extracorporeal membrane oxygenation (ECMO) combined with continuous renal replacement therapy without any serious complications or neurological deficits. We report a patient who was successfully treated for Gd-DTPA-induced cardiac arrest with ECMO. Thus, ECMO may be an effective treatment for cardiac arrest secondary to anaphylaxis.


Asunto(s)
Reanimación Cardiopulmonar , Oxigenación por Membrana Extracorpórea , Paro Cardíaco , Masculino , Humanos , Gadolinio DTPA , Oxigenación por Membrana Extracorpórea/efectos adversos , Oxigenación por Membrana Extracorpórea/métodos , Electrocardiografía/efectos adversos , Paro Cardíaco Inducido/efectos adversos , Paro Cardíaco/etiología , Paro Cardíaco/terapia
10.
Ecotoxicol Environ Saf ; 256: 114874, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37054469

RESUMEN

Lead (Pb), cadmium (Cd) and total mercury (THg) are toxic heavy metals (THMs) that are widely present in the environment and can cause substantial health problems. However, previous risk assessment studies have rarely focused on the elderly population and have usually targeted a single heavy metal, which might underestimate the long-term accumulative and synergistic effects of THMs in humans. Based on the food frequency questionnaire and inductively coupled plasma mass spectrometry, this study assessed external and internal exposures to Pb, Cd and THg in 1747 elderly people in Shanghai. Probabilistic risk assessment with the relative potential factor (RPF) model was used to assess the neurotoxicity and nephrotoxicity risks of combined THMs exposures. The mean external exposures of Pb, Cd and THg in Shanghai elderly were 46.8, 27.2 and 4.9 µg/day, respectively. Plant-based foods are the main source of Pb and THg exposure, while Cd is mainly from animal-based foods. The mean concentrations of Pb, Cd and THg were 23.3, 1.1 and 2.3 µg/L in the whole blood, and 6.2, 1.0 and 2.0 µg/L in the morning urine, respectively. Combined exposure to THMs leading to 10.0 % and 7.1 % of Shanghai elderly at risk of neurotoxicity and nephrotoxicity. The results of this study have important implications for understanding the profiles of Pb, Cd and THg exposure in the elderly living in Shanghai and provide data support for risk assessment and control of nephrotoxicity and neurotoxicity from combined THMs exposure in the elderly.


Asunto(s)
Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Mercurio , Metales Pesados , Síndromes de Neurotoxicidad , Animales , Humanos , Anciano , Cadmio/toxicidad , Mercurio/análisis , Plomo/análisis , China , Metales Pesados/análisis , Intoxicación por Metales Pesados , Medición de Riesgo
11.
J Craniofac Surg ; 34(6): 1851-1854, 2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37463297

RESUMEN

The authors report a case of intracranial arteriovenous malformation in functional areas, initially presenting with symptomatic epilepsy was surgically excised by the Neurosurgery Department of our hospital. The patient's head computed tomography, magnetic resonance imaging, and digital subtraction angiography examination suggested intracranial arteriovenous malformations in the left frontal functional area. A preoperative 3D-reconstruction technique was used to reconstruct the malformed vascular mass, supplying arteries, draining veins, and precise surgical resection was performed. Postoperative pathology indicated vascular malformation. No seizures occurred after surgery. There was no further neurological impairment. Preoperative use of image postprocessing techniques can facilitate precise surgical resection of brain arteriovenous malformations. Three-dimensional Slicer in cerebral arteriovenous malformations in functional areas not only shortened the preoperative planning time but also improved the efficiency of the surgery. Reduce the incidence of postoperative complications. It is helpful for further popularization and application.


Asunto(s)
Imagenología Tridimensional , Malformaciones Arteriovenosas Intracraneales , Humanos , Malformaciones Arteriovenosas Intracraneales/complicaciones , Malformaciones Arteriovenosas Intracraneales/diagnóstico por imagen , Malformaciones Arteriovenosas Intracraneales/cirugía , Imagen por Resonancia Magnética , Tomografía Computarizada por Rayos X , Angiografía Cerebral , Angiografía de Substracción Digital , Masculino , Adulto Joven , Imagenología Tridimensional/métodos , Resultado del Tratamiento
12.
Pharmacol Res ; 180: 106244, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35550167

RESUMEN

Sorafenib, a multikinase inhibitor, has been widely used as a first-line anticancer drug for advanced hepatocellular carcinoma (HCC). However, the development of drug resistance to sorafenib is frequently observed in clinical applications. Potential nonkinase targets of sorafenib have not been well documented and may provide insights into reversing drug resistance and enhancing drug efficacy. Herein, we report that sorafenib exerts its anticancer effects by activating metallothionein 1 G (MT1G) expression. MT1G is a novel marker in HCC that correlates well with patient survival. MT1G overexpression suppressed the cellular proliferation, migration, invasion, and tumour formation of HCC and sensitised cells to sorafenib treatment. However, the disruption of MT1G attenuated the anticancer effects of sorafenib. Mechanistically, sorafenib upregulated MT1G expression via hypomethylation of its promoter region by binding and inhibiting DNA methyltransferase 1 (DNMT1) and increasing its promoter accessibility in HCC cells. Activation of MT1G also inhibited CA9 transcription through the suppression of HIF1A as mediated by KLF4. Our collective data revealed that sorafenib exerts its anticancer effects through epigenetic regulation of the DNMT1/MT1G/KLF4/CA9 axis in HCC and the activation of MT1G might constitute a strategy for enhancing the effect of sorafenib to suppress HCC cells.


Asunto(s)
Antineoplásicos , Carcinoma Hepatocelular , Neoplasias Hepáticas , Sorafenib , Antígenos de Neoplasias , Antineoplásicos/farmacología , Anhidrasa Carbónica IX/genética , Anhidrasa Carbónica IX/metabolismo , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Proliferación Celular , ADN (Citosina-5-)-Metiltransferasa 1/genética , ADN (Citosina-5-)-Metiltransferasa 1/metabolismo , Resistencia a Antineoplásicos , Epigénesis Genética , Humanos , Factor 4 Similar a Kruppel/genética , Factor 4 Similar a Kruppel/metabolismo , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , Metalotioneína/genética , Metalotioneína/metabolismo , Transducción de Señal/efectos de los fármacos , Sorafenib/farmacología
13.
Sensors (Basel) ; 22(12)2022 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-35746202

RESUMEN

Meta-learning frameworks have been proposed to generalize machine learning models for domain adaptation without sufficient label data in computer vision. However, text classification with meta-learning is less investigated. In this paper, we propose SumFS to find global top-ranked sentences by extractive summary and improve the local vocabulary category features. The SumFS consists of three modules: (1) an unsupervised text summarizer that removes redundant information; (2) a weighting generator that associates feature words with attention scores to weight the lexical representations of words; (3) a regular meta-learning framework that trains with limited labeled data using a ridge regression classifier. In addition, a marine news dataset was established with limited label data. The performance of the algorithm was tested on THUCnews, Fudan, and marine news datasets. Experiments show that the SumFS can maintain or even improve accuracy while reducing input features. Moreover, the training time of each epoch is reduced by more than 50%.


Asunto(s)
Algoritmos , Aprendizaje Automático , Vocabulario
14.
Waste Manag Res ; 40(6): 736-744, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34334056

RESUMEN

Aiming to reveal the humification process of organic waste and its contribution to the heavy metal behaviour affected by earthworm activity, it was studied about the variation of humic acid (HA) and heavy metal behaviour during vermicomposting of the mixed pig manure and 13C-labelled rice straw. The results showed that earthworms could well adapt to the culturing environment and feed organic matter for its growth and reproduction, the vermicomposting process increased the content of humic substances (HS), HA, and fulvic acid (FA) in substrate residues, but led to less transformation of HA into FA. The elemental, ultraviolet absorption spectroscopy, Fourier transform infrared (FTIR) and fluorescence excitation-emission matrix (EEM) analysis indicated that vermicomposting led to more aromatic structures and much higher humification degree in HA, whereas less protein, FA-like substances and plastein in HA. Vermicomposting could enhance the total Cu content and decrease Cu/Zn bioavailability in the substrate residues, and vermicomposting especially can help stabilize Cu in the substrate residues by forming more complexed HA-Cu.


Asunto(s)
Metales Pesados , Oligoquetos , Oryza , Animales , Sustancias Húmicas/análisis , Estiércol , Oligoquetos/metabolismo , Porcinos
15.
Am J Transplant ; 21(1): 208-221, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32519434

RESUMEN

INTRODUCTION: Cytomegalovirus (CMV) remains associated with poor outcomes after kidney transplantation (kTx). The impact of belatacept on CMV infection remains understudied. In this study, we assessed the impact of belatacept on patient and graft survivals. METHODS: CMV seronegative kTx recipients were included. Patient and graft survival were studied using Kaplan-Meier method, log-rank test. Cox models were used to compare outcomes by CMV risk and immunosuppressive regimen. Incidence and persistence of CMV viremia under belatacept vs tacrolimus were compared. RESULTS: Among 308 CMV seronegative recipients, 168 CMV high-risk and 203 belatacept-treated patients were included. High-risk CMV status was associated with lower patient survival and graft survival. Among the CMV high-risk group, patients treated with belatacept presented a higher incidence of CMV viremia, a higher rate of first-line treatment failure and a longer time to virus clearance. They had a nonsignificant trend toward a lower graft survival. CONCLUSION: Belatacept-based maintenance immunosuppression is associated with an increased risk of CMV primary-infection and a prolonged course of viral replication in CMV high-risk patients. Further studies are needed to confirm the nonsignificant trend towards a lower graft survival in CMV high-risk patients treated with belatacept and whether it is explained by the higher risk of CMV reactivation and infection.


Asunto(s)
Infecciones por Citomegalovirus , Trasplante de Riñón , Abatacept/uso terapéutico , Infecciones por Citomegalovirus/tratamiento farmacológico , Infecciones por Citomegalovirus/epidemiología , Rechazo de Injerto/tratamiento farmacológico , Rechazo de Injerto/etiología , Rechazo de Injerto/prevención & control , Supervivencia de Injerto , Humanos , Inmunosupresores/uso terapéutico , Trasplante de Riñón/efectos adversos , Factores de Riesgo , Receptores de Trasplantes
16.
Environ Microbiol ; 23(5): 2692-2703, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33848059

RESUMEN

Labelling of Type IV pili (TFP) can greatly improve our understanding of the pivotal roles of TFP in a variety of bacterial activities including motility, surface sensing and DNA-uptake etc. Here we show a simple and switchable pili-labelling method by plasmid-based inducible replacement of PilA without genetic modification in bacterial genome employed by complicated methods. Using this method, we characterized pili morphology and twitching motility of Pseudomonas aeruginosa in details. More importantly, we demonstrate its application in studying the replenishment dynamics of pilin pool of P. aeruginosa.


Asunto(s)
Proteínas Bacterianas , Proteínas Fimbrias , Proteínas Bacterianas/genética , Proteínas Fimbrias/genética , Fimbrias Bacterianas/genética , Plásmidos/genética , Pseudomonas aeruginosa/genética
17.
Ecotoxicol Environ Saf ; 215: 112163, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33756288

RESUMEN

Cadmium (Cd) contamination has become serious in soil and in situ stabilization technology has been widely used for heavy metal remediation. A field study was conducted to determine the effect of amendments with the doses of 3 kg/m2, including single vermicompost (A1), a 95% vermicompost mixed with 5% shell powder composite (A2) and a 95% vermicompost mixed with 5% modified shell powder composite (A3), on the Cd bioavailability, enzyme activity and bacterial community in soil, and the experiment was conducted with lettuce (Lactuca sativa L.) grown in a Cd-contaminated farmland soil. The results showed that the application of amendments increased the pH, cation exchange capacity (CEC), organic matter (OM), available nutrients, catalase (S-CAT), invertase (S-SC) and urease (S-UE) activities in soil, while significantly reduced the Cd bioavailability with the lowest Cd bioavailability being observed in the soil with A3 application. The soil bacterial richness and diversity increased after amendments application, and the bacterial community was characterized by an increase in metal-tolerant bacteria but a decrease in Proteobacteria, Acidobacteria and Gemmatimonadetes. In addition, the application of amendments significantly improved the growth of lettuce (Lactuca sativa L.) and inhibited Cd accumulation in its edible parts, especially, the Cd content in lettuce (Lactuca sativa L.) grown in soil with A3 application was below the limit of the National Food Safety Standard of China (maximum level ≤ 0.2 mg/kg). Thus, composite amendment obtained from vermicompost mixed with modified shell powder can be used as potential remediation material in Cd-contaminated soil. CAPSULE: Composite amendment obtained from vermicompost and modified shell powder had good effects on remediation of Cd-contaminated soil.


Asunto(s)
Cadmio/análisis , Microbiología del Suelo , Contaminantes del Suelo/análisis , Acidobacteria , Bacterias , Disponibilidad Biológica , China , Contaminación Ambiental , Granjas , Lactuca , Metales Pesados , Polvos , Proteobacteria , Suelo/química , Ureasa
18.
Metab Eng ; 61: 275-287, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32707168

RESUMEN

With the ability to recycle CO2 into value-added chemicals, cyanobacteria have been considered as renewable microbial cell factories. Astaxanthin, a highly valued carotenoid with potent antioxidant activity, could be beneficial to human health. Astaxanthin biosynthesis in engineered chassis has been achieved previously, but it generated a relatively low yield. Here, we successfully constructed a highly efficient astaxanthin biosynthetic pathway in cyanobacterium Synechocystis sp. PCC 6803, and achieved more than a 500-fold increase in astaxanthin production via stepwise reconstruction of the biosynthetic pathway and rational rewiring of the endogenous metabolism. The engineered strain produced up to 29.6 mg/g of astaxanthin (dry cell weight), which is the highest yield reported in the engineered chassis to date. Moreover, multi-omics analyses revealed that establishing a high astaxanthin flux may enhance photosynthesis and central metabolism in the engineered strain to compensate for the depleted pigments, which could be valuable for astaxanthin overproduction. This study presents a novel alternative for high-efficiency biosynthesis of astaxanthin directly from CO2.


Asunto(s)
Ingeniería Metabólica , Microorganismos Modificados Genéticamente , Synechocystis , Microorganismos Modificados Genéticamente/genética , Microorganismos Modificados Genéticamente/metabolismo , Synechocystis/genética , Synechocystis/metabolismo , Xantófilas/metabolismo
19.
Microb Cell Fact ; 19(1): 91, 2020 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-32299433

RESUMEN

BACKGROUND: Docosahexaenoic acid (DHA) is essential for human diet. However, high production cost of DHA using C. cohnii makes it currently less competitive commercially, which is mainly caused by low DHA productivity. In recent years, repeated fed-batch strategies have been evaluated for increasing the production of many fermentation products. The reduction in terms of stability of culture system was one of the major challenges for repeated fed-batch fermentation. However, the possible mechanisms responsible for the decreased stability of the culture system in the repeated fed-batch fermentation are so far less investigated, restricting the efforts to further improve the productivity. In this study, a repeated fed-batch strategy for DHA production using C. cohnii M-1-2 was evaluated to improve DHA productivity and reduce production cost, and then the underlying mechanisms related to the gradually decreased stability of the culture system in repeated fed-batch culture were explored through LC- and GC-MS metabolomic analyses. RESULTS: It was discovered that glucose concentration at 15-27 g/L and 80% medium replacement ratio were suitable for the growth of C. cohnii M-1-2 during the repeated fed-batch culture. A four-cycle repeated fed-batch culture was successfully developed and assessed at the optimum cultivation parameters, resulting in increasing the total DHA productivity by 26.28% compared with the highest DHA productivity of 57.08 mg/L/h reported using C. cohnii, including the time required for preparing seed culture and fermentor. In addition, LC- and GC-MS metabolomics analyses showed that the gradually decreased nitrogen utilization capacity, and down-regulated glycolysis and TCA cycle were correlated with the decreased stability of the culture system during the long-time repeated fed-batch culture. At last, some biomarkers, such as Pyr, Cit, OXA, FUM, L-tryptophan, L-threonine, L-leucine, serotonin, and 4-guanidinobutyric acid, correlated with the stability of culture system of C. cohnii M-1-2 were identified. CONCLUSIONS: The study proved that repeated fed-batch cultivation was an efficient and energy-saving strategy for industrial production of DHA using C. cohnii, which could also be useful for cultivation of other microbes to improve productivity and reduce production cost. In addition, the mechanisms study at metabolite level can also be useful to further optimize production processes for C. cohnii and other microbes.


Asunto(s)
Técnicas de Cultivo Celular por Lotes , Ácidos Docosahexaenoicos/biosíntesis , Metabolómica , Microalgas/metabolismo , Medios de Cultivo/metabolismo , Ácidos Docosahexaenoicos/química , Microalgas/química
20.
Metab Eng ; 51: 88-98, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30393203

RESUMEN

Dietary omega-3 long-chain polyunsaturated fatty acids docosahexaenoic acid (DHA, C22:6) can be synthesized in microalgae Crypthecodinium cohnii; however, its productivity is still low. Here, we established a new protocol termed as "chemical modulator based adaptive laboratory evolution" (CM-ALE) to enhance lipid and DHA productivity in C. cohnii. First, ACCase inhibitor sethoxydim based CM-ALE was applied to redirect carbon equivalents from starch to lipid. Second, CM-ALE using growth modulator sesamol as selection pressure was conducted to relive negative effects of sesamol on lipid biosynthesis in C. cohnii, which allows enhancement of biomass productivity by 30% without decreasing lipid content when sesamol was added. After two-step CM-ALE, the lipid and DHA productivity in C. cohnii was respectively doubled to a level of 0.046 g/L/h and 0.025 g/L/h in culture with addition of 1 mM sesamol, demonstrating that this two-step CM-ALE could be a valuable approach to maximize the properties of microalgae.


Asunto(s)
Dinoflagelados/metabolismo , Evolución Molecular Dirigida/métodos , Lípidos/biosíntesis , Redes y Vías Metabólicas/efectos de los fármacos , Redes y Vías Metabólicas/genética , Acetil-CoA Carboxilasa/metabolismo , Benzodioxoles/farmacología , Biomasa , Carbono/metabolismo , Ciclohexanonas/farmacología , Ácidos Docosahexaenoicos/biosíntesis , Malonil Coenzima A/metabolismo , Fenoles/farmacología , Especies Reactivas de Oxígeno/metabolismo , Almidón/metabolismo
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