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The rampant hepatitis B virus (HBV) seriously endangers human health, and hepatitis B surface antigen (HBsAg) is its early diagnostic marker. Therefore, it is crucial to construct a fast and highly sensitive HBsAg detection method. Based on high-efficiency magnetic separation technology and fluorescent composite material labelling technology, an accurate, fast and sensitive fluorescent immunosensing system for HBsAg detection was developed. Immunomagnetic beads constructed from carboxyl-functionalized Fe3O4 nanoparticles (Fe3O4-COOH) with excellent magnetic response performance were used as efficient capture carriers for HBsAg. Immunofluorescence composite microspheres constructed based on ultra-stable polystyrene-coated CsPbBr3 perovskite nanocrystals (CPB@PSAA) with high hydrophilic properties, were excellent fluorescent markers for HBsAg. Using this sensitive sandwich fluorescence sensing system a good linear relationship within the range of 0.2-15 ng/mL was established between HBsAg concentration and fluorescence intensity with a limit of detection (LOD) of 0.05 ng/mL. The system obtained satisfactory results when tested on real human serum samples. The magnetic-assisted fluorescence immune-sandwich sensor system has broad application prospects in biomedicine such as rapid and early diagnosis and effective prevention of infectious diseases.
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Compuestos de Calcio , Antígenos de Superficie de la Hepatitis B , Interacciones Hidrofóbicas e Hidrofílicas , Límite de Detección , Óxidos , Titanio , Antígenos de Superficie de la Hepatitis B/sangre , Antígenos de Superficie de la Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/análisis , Humanos , Óxidos/química , Titanio/química , Compuestos de Calcio/química , Colorantes Fluorescentes/química , Nanopartículas de Magnetita/química , Microesferas , Anticuerpos Inmovilizados/inmunología , Virus de la Hepatitis B/inmunología , Virus de la Hepatitis B/aislamiento & purificación , Inmunoensayo/métodosRESUMEN
In the spring of 2023, 10 to 21-day-old chicks in a broiler duck farm in Shandong Province, China, developed swelling of the head and neck, moist eyes with mucous discharge, difficulty in walking, shrinking of the neck, and loose and disorganized coat. Anatomical observation revealed hemorrhages in the esophageal mucosa, myocardium, and liver, and severe hemorrhages in the trachea with copious inflammatory secretions. Soon after, similar symptoms appeared in a large number of ducks in the flock, which eventually led to the elimination of all the 20,000-odd newly introduced ducklings on the farm, resulting in huge economic losses. We detected duck plague virus in the tissues of liver, spleen and lungs of diseased and dead ducks, and successfully isolated the pathogenic strain, named SD423, by inoculating duck embryos and inoculating duck embryo fibroblasts. We successfully conducted animal regression experiments with the isolated strain, and the experimental animals in the 1 d of age group showed symptoms of swollen eyes and tearing, shrinking of the neck, crouching, and hemorrhage in organs such as the liver and intestines successively from the 3rd d. We sequenced the whole genome of the isolated duck plague strain, and by comparing the homology with the published duck plague virus whole sequences in Genbank, the virus strain obtained in this study had the highest homology with the Chinese virulent strain SD (MN518864.1), with nucleotide (nt) homology of about 99.90% and amino acid (aa) homology of about 99.75%, which indicated that the isolate is a virulent strain. Previously, it was reported that the natural infection of duck plague virus mainly occurs above 30 d of age, but the duck plague virus found in this study can naturally infect ducklings up to 20 d of age, and the mortality rate is as high as 100%. In this study, the pathogenicity test and whole genome sequence analysis of this isolate provided data support and theoretical basis for further research on pathogenicity and virulence-related gene analysis of duck plague virus.
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Patos , Enfermedades de las Aves de Corral , Animales , Enfermedades de las Aves de Corral/virología , Enfermedades de las Aves de Corral/patología , Infecciones por Herpesviridae/veterinaria , Infecciones por Herpesviridae/virología , China , Virulencia , Alphaherpesvirinae/genética , Alphaherpesvirinae/patogenicidad , MardivirusRESUMEN
Background: Music therapy is increasingly examined in randomized controlled trials (RCTs) and shows potential in treating post-traumatic stress disorder (PTSD).Objective: This systematic review and meta-analysis critically evaluates the current clinical evidence supporting the efficacy and acceptability of music therapy for PTSD.Method: RCTs comparing music therapy in addition to care as usual (CAU) versus either CAU alone or CAU combined with standard psychotherapy/pharmacotherapy for PTSD were retrieved from major English - and Chinese-language databases. Standardized mean differences (SMDs) for post-treatment PTSD symptom scores and risk differences (RDs) for retention rates upon treatment completion were calculated to assess the efficacy and acceptability of music therapy, respectively. The Cochrane risk of bias (RoB) tool 2.0 and the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) were used to assess the RoB of included studies and certainty of the evidence, respectively.Results: Nine studies, incorporating 527 PTSD patients, were included, all with high RoB. The post-treatment PTSD symptom scores were significantly lower in the music therapy group than the inactive control group (SMD = -1.64, P < .001), but comparable between the music therapy group and the active control group (SMD = -0.28, P = .330). The retention rates did not differ significantly between the music therapy group and both control groups (RD = 0.03, P = .769; RD = 0.16, P = .829). The GRADE rated certainty level of evidence as low.Conclusions: Although meta-analytic findings suggest that music therapy is effective in reducing post-traumatic symptoms in individuals with PTSD, with its therapeutic effect comparable to that of standard psychotherapy, the low level of certainty limits its generalizability. More methodologically stringent studies are warranted to strengthen the clinical evidence for the efficacy and acceptability of music therapy for PTSD.
This systematic review critically appraised the existing methodologically rigorous evidence for the efficacy and acceptability of music therapy for post-traumatic stress disorder (PTSD).The post-treatment PTSD symptom scores were significantly lower in the music therapy group than the inactive control group and comparable between the music therapy group and the active control group.The post-treatment retention rates did not differ significantly between the music therapy group and both the inactive and active control groups.
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Musicoterapia , Ensayos Clínicos Controlados Aleatorios como Asunto , Trastornos por Estrés Postraumático , Humanos , Trastornos por Estrés Postraumático/terapia , Resultado del TratamientoRESUMEN
Iridovirus poses a substantial threat to global aquaculture due to its high mortality rate; however, the molecular mechanisms underpinning its pathogenesis are not well elucidated. Here, a multi-omics approach was applied to groupers infected with Singapore grouper iridovirus (SGIV), focusing on the roles of key metabolites. Results showed that SGIV induced obvious histopathological damage and changes in metabolic enzymes within the liver. Furthermore, SGIV significantly reduced the contents of lipid droplets, triglycerides, cholesterol, and lipoproteins. Metabolomic analysis indicated that the altered metabolites were enriched in 19 pathways, with a notable down-regulation of lipid metabolites such as glycerophosphates and alpha-linolenic acid (ALA), consistent with disturbed lipid homeostasis in the liver. Integration of transcriptomic and metabolomic data revealed that the top enriched pathways were related to cell growth and death and nucleotide, carbohydrate, amino acid, and lipid metabolism, supporting the conclusion that SGIV infection induced liver metabolic reprogramming. Further integrative transcriptomic and proteomic analysis indicated that SGIV infection activated crucial molecular events in a phagosome-immune depression-metabolism dysregulation-necrosis signaling cascade. Of note, integrative multi-omics analysis demonstrated the consumption of ALA and linoleic acid (LA) metabolites, and the accumulation of L-glutamic acid (GA), accompanied by alterations in immune, inflammation, and cell death-related genes. Further experimental data showed that ALA, but not GA, suppressed SGIV replication by activating antioxidant and anti-inflammatory responses in the host. Collectively, these findings provide a comprehensive resource for understanding host response dynamics during fish iridovirus infection and highlight the antiviral potential of ALA in the prevention and treatment of iridoviral diseases.
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Enfermedades de los Peces , Iridovirus , Hígado , Ácido alfa-Linolénico , Animales , Ácido alfa-Linolénico/metabolismo , Enfermedades de los Peces/virología , Enfermedades de los Peces/metabolismo , Hígado/metabolismo , Hígado/virología , Iridovirus/fisiología , Infecciones por Virus ADN/veterinaria , Infecciones por Virus ADN/virología , Metabolómica , Antivirales/farmacología , Transcriptoma , Reprogramación Metabólica , MultiómicaRESUMEN
Background: The prevalence of prolonged grief disorder (PGD) and its symptoms among the bereaved population in China vary considerably. Aims: This meta-analysis aims to estimate the prevalence of PGD and its symptoms among bereaved individuals in China. Methods: We conducted a literature search in major Chinese and English databases from their inception to 4 October 2023, for cross-sectional studies on the prevalence of PGD or its symptoms in bereaved Chinese individuals. The risk of bias of the included studies and certainty of the evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data ('JBI checklist') and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE), respectively. The 'metaprop' package in R V.4.1.2 was used to synthesise the prevalence. Results: A total of 28 studies involving 10 994 bereaved individuals were included in the analysis, with JBI checklist scores between 3 and 7. The combined prevalence (95% confidence interval) of PGD and its symptoms was 8.9% (4.2% to 17.6%) and 32.4% (18.2% to 50.8%), respectively. PGD and its symptoms were most prevalent among those who had lost their only child (22.7%) and those bereaved by earthquakes (80.4%), respectively. The GRADE system assigned a very low certainty level to the evidence for the pooled prevalence of PGD and its symptoms. Conclusions: The pooled prevalence of PGD and its symptoms indicate a potential high need for grief counselling services among bereaved individuals in China. This need is particularly pronounced in those who have lost their only child and those bereaved due to earthquakes. Further methodologically rigorous studies are needed to provide more accurate prevalence estimates. PROSPERO registration number: CRD42023432553.
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Quantitative fluorescence immunoassay is essential for the construction of biosensing mechanisms and the quantification of trace markers. But the interference problems caused by low fluorescence efficiency and broad fluorescence spectrum of fluorescent probes have hindered the continued development of ratiometric fluorescence sensing in biosensing. Perovskite materials, with ultra-high color purity (FWHM < 30 nm) and photoluminescence quantum yield (PLQY) (close to 100%), are expected to be next-generation fluorescent probes. However, poor water stability and biocompatibility are still non-negligible in biosensor applications. In this work, hyperstatic perovskite fluorescent microspheres prepared by swelling-shrinking method can be used as ratiometric fluorescence signals and biological immunoassay platforms. Meanwhile, inspired by p-aminophenol (AP) controlled synthesis and the catalytic reaction of 4-aminophenol phosphate (APP) triggered by alkaline phosphatase (ALP), a strategy to prepare fluorescent nanoparticles as fluorescence signals for ALP detection is proposed. Most importantly, it is proposed for the first time to combine this enzymatic fluorescence with perovskite materials using covalent linkage to create a novel cascade immunoassay and use it for quantitative and visualization determination of hepatitis B surface antigen (HBsAg) for application verification. These results indicate the biosensing potential of perovskite materials and provide a pathway for high sensitivity enzyme detection and enzyme triggered immune detection.
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Técnicas Biosensibles , Compuestos de Calcio , Nanopartículas , Óxidos , Puntos Cuánticos , Titanio , Colorantes Fluorescentes , Espectrometría de Fluorescencia/métodos , Fosfatasa Alcalina , Inmunoensayo , Técnicas Biosensibles/métodosRESUMEN
A set of high-quality pan-genomes would help identify important genes that are still hidden/incomplete in bird reference genomes. In an attempt to address these issues, we have assembled a de novo chromosome-level reference genome of the Silkie (Gallus gallus domesticus), which is an important avian model for unique traits, like fibromelanosis, with unclear genetic foundation. This Silkie genome includes the complete genomic sequences of well-known, but unresolved, evolutionarily, endocrinologically, and immunologically important genes, including leptin, ovocleidin-17, and tumor-necrosis factor-α. The gap-less and manually annotated MHC (major histocompatibility complex) region possesses 38 recently identified genes, with differentially regulated genes recovered in response to pathogen challenges. We also provide whole-genome methylation and genetic variation maps, and resolve a complex genetic region that may contribute to fibromelanosis in these animals. Finally, we experimentally show leptin binding to the identified leptin receptor in chicken, confirming an active leptin ligand-receptor system. The Silkie genome assembly not only provides a rich data resource for avian genome studies, but also lays a foundation for further functional validation of resolved genes.
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Pollos , Leptina , Animales , Pollos/genética , Leptina/genética , Genoma , Genómica , CromosomasRESUMEN
Purpose: Social distancing measures implemented during the COVID-19 pandemic have contributed to increased levels of loneliness, but the specific interactions between loneliness symptoms in the context of the pandemic remain unknown. This study characterized the psychological network of loneliness symptoms in residents during the initial wave of COVID-19 outbreak in China. Patients and Methods: The study recruited 8472 Chinese residents (61.5% women, aged 33.0±10.6 years) through online snowball sampling. The Six-item De Jong Gierveld Loneliness Scale (DJGLS) was used to measure loneliness symptoms. Central symptoms of and bridge symptoms between emotional and social loneliness subscales were identified based on centrality and bridge centrality indices, respectively. Network stability was examined using the case-dropping procedures. Results: The nodes in the loneliness network were separated into two groups, corresponding to the social and emotional loneliness domains of the DJGLS. The strongest direction association was between "no reliable people" and "no trustworthy people" (edge weight=0.546). "No trustworthy people" has the highest node strength (1.047) in the loneliness network, followed by "emptiness sense" (0.767) and "no reliable people" (0.749). "Feeling of rejection" (1.672) and "no close people" (0.403) showed the first and second highest bridge strengths, respectively. Both the stability and accuracy tests supported robustness of the whole network. Conclusion: Interventions targeting central symptoms "no trustworthy people" and "emptiness sense" and central bridge symptom "feeling of rejection" may be effective for alleviating the overall level of loneliness in pandemic-affected Chinese residents.
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The effects of ultrasound-assisted slightly acidic electrolyzed water thawing (UET), air thawing (AT), water thawing (WT) and microwave thawing (MT) on the quality, nutrients and microstructure were investigated. The UET treatment did not affect the lightness (L*) but reduced the redness (a*) and yellowness (b*) of the mutton. The UET treatment could better maintain the textural properties. The UET group had a higher immobilized water and lower free water, which was closer to the state of the control group. The UET treatment not only effectively inhibited the lipid oxidation but also reduced the loss of nutrients, especially minerals. The microstructure of the UET group was smoother and more complete, and the muscle fibers did not show significant breakage. In conclusion, UET treatment could better maintain the quality, nutrients and microstructure of thawed mutton. Therefore, UET could be regarded as a potential thawing method for application in the processing of meat products.
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AIMS: This study mainly evaluated the protective mechanism of histidine against the hepatic oxidative stress after high-salt exposure (HSE) through combined analysis of non-targeted metabolomics and biological metabolic networks. MATERIALS AND METHODS: Dahl salt-sensitive (SS) rats were fed with normal-salt diet or HSE ± histidine in addition to drinking water for 14 days. Gas chromatography-mass spectrometry was used to analyze the hepatic metabolites. The metabolic profile was analyzed by SIMCA-14.1, the metabolic correlation network was performed using Gephi-0.9.2, and pathway enrichment was analyzed using MetaboAnalyst 5.0 online website. KEY FINDINGS: Results indicated that HSE disturbed the hepatic metabolic profile, generated abnormal liver metabolism and exacerbated oxidative stress. Histidine supplementation significantly reversed the hepatic metabolic profile. Of note, 14 differential metabolic pathways were enriched after histidine supplementation, most of which played an important role in ameliorating redox and nitric oxide (NO) metabolism. Histidine administration decreased the levels of hydroperoxide and malondialdehyde, and increased the activities of antioxidant enzymes (Catalase, Superoxide Dismutase, Glutathione S-transferase and Glutathione reductases). Histidine effectively enhanced the endogenous synthesis of glutathione by increasing the levels of glutamate and cysteine, thereby enhancing the antioxidant capacity of the glutathione system. After histidine administration, lysine, glutamate, and hypotaurine owned a higher metabolic centrality in the correlation network. In addition, histidine could also effectively increase the endogenous synthesis of NO by enhancing the L-arginine/NO pathway. SIGNIFICANCE: This study offers new insights into the metabolic mechanisms underlying the antioxidant protective effect of histidine on the liver.
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Antioxidantes , Histidina , Estrés Oxidativo , Cloruro de Sodio Dietético , Animales , Ratas , Antioxidantes/farmacología , Antioxidantes/metabolismo , Suplementos Dietéticos , Glutamatos/farmacología , Glutatión/metabolismo , Histidina/farmacología , Histidina/metabolismo , Hígado/metabolismo , Metabolómica , Oxidación-Reducción , Ratas Endogámicas Dahl , Cloruro de Sodio Dietético/efectos adversos , Cloruro de Sodio Dietético/metabolismo , Superóxido Dismutasa/metabolismoRESUMEN
The effects of air thawing (AT), water immersion thawing (WT), microwave thawing (MT) and ultrasound combined with slightly acidic electrolyzed water thawing (UST) on the myofibrillar protein (MP) properties (surface hydrophobicity, solubility, turbidity, particle size and zeta potential), protein oxidation (carbonyl content and sulfhydryl content) and structure (primary, secondary and tertiary) of frozen mutton were investigated in comparison with fresh mutton (FM). The solubility and turbidity results showed that the MP properties were significantly improved in the UST treatment. UST treatment could effectively reduce the MP aggregation and enhance the stability, which was similar to the FM. In addition, UST treatment could effectively inhibit protein oxidation during thawing as well. The primary structure of MP was not damaged by the thawing methods. UST treatment could reduce the damage to MP secondary and tertiary structure during the thawing process compared to other thawing methods. Overall, the UST treatment had a positive influence in maintaining the MP properties by inhibiting protein oxidation and protecting protein structure.
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Carne Roja , Agua , Agua/química , Proteínas , Oxidación-Reducción , Interacciones Hidrofóbicas e HidrofílicasRESUMEN
Microbial production of monoterpenoid indole alkaloids (MIAs) provides a sustainable and eco-friendly means to obtain compounds with high pharmaceutical values. However, efficient biosynthesis of MIAs in heterologous microorganisms is hindered due to low supply of key precursors such as geraniol and its derivative 8-hydroxygeraniol catalyzed by geraniol 8-hydroxylase (G8H). In this study, we developed a facile evolution platform to screen strains with improved yield of geraniol by using the SCRaMbLE system embedded in the Sc2.0 synthetic yeast and confirmed the causal role of relevant genomic targets. Through genome mining, we identified several G8H enzymes that perform much better than the commonly used CrG8H for 8-hydroxygeraniol production in vivo. We further showed that the N-terminus of these G8H enzymes plays an important role in cellular activity by swapping experiments. Finally, the combination of the engineered chassis, optimized biosynthesis pathway, and utilization of G8H led to the final strain with more than 30-fold improvement in producing 8-hydroxygeraniol compared with the starting strain. Overall, this study will provide insights into the construction and optimization of yeast cells for efficient biosynthesis of 8-hydroxygeraniol and its derivatives.
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Salt-induced renal metabolism dysfunction is an important mechanism of salt-sensitive hypertension. Given that the gut-liver axis is the first hit of a high-salt diet (HSD), we aimed to identify the extra-renal mechanism from hepatic metabolism and gut microbiota, and attempted to relieve the salt-induced metabolic dysfunctions by curcumin. Untargeted metabolomics analysis was performed to identify the changes in hepatic metabolic pathways, and integrated analysis was employed to reveal the relationship between hepatic metabolic dysfunction and gut microbial composition. HSD induced significant increase in fumaric acid, l-lactic acid, creatinine, l-alanine, glycine, and l-cysteine levels, and amino acids metabolism pathways associated with glycolysis were significantly altered, including alanine, aspartate, and glutamate metabolism; glycine, serine, and threonine metabolism, which were involved in the regulation of blood pressure. Integrated multi-omics analysis revealed that changes in Paraprevotella, Erysipelotrichaceae, and genera from Clostridiales are associated with metabolic disorders. Gene functional predication analysis based on 16S Ribosomal RNA sequences showed that the dysfunction in hepatic metabolism were correlated with enhanced lipopolysaccharide (LPS) biosynthesis and apoptosis in gut microbes. Curcumin (50 mg/kg/d) might reduce gut microbes-associated LPS biosynthesis and apoptosis, partially reverse metabolic dysfunction, ameliorate renal oxidative stress, and protect against salt-sensitive hypertension.
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Background: Parents who lost their only child and cannot have a second child ("Shidu") have been a large population in China. Prolonged grief disorder (PGD) in Shidu parents is of clinical and public health concern but the reported PGD prevalence varies widely. To facilitate the planning of grief counseling services, this meta-analysis estimated prevalence of PGD and its symptoms and identified subgroups at elevated risk for PGD. Methods: We searched English and Chinese literature databases to identify cross-sectional surveys reporting prevalence of PGD or PGD symptoms in Chinese Shidu parents. The Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data ("JBI") was used to assess risk of bias of included studies. Results: Seven studies with a total of 2,794 Shidu parents were included and their JBI scores ranged from five to eight. The pooled prevalence of PGD and PGD symptoms was 20.9% and 75.0%, respectively. Greater risk of PGD was observed in mothers [vs. fathers, OR (odds ratio) = 1.89, P = 0.001] and in parents with religious beliefs (vs. without religious beliefs, OR = 1.65, P = 0.040). More severe PGD symptoms were presented in parents whose only child died from accidents [vs. illness, MD (mean difference) = 3.99, P < 0.001]. Deceased children of PGD parents were older than those of non-PGD parents (MD = 1.64, P = 0.035) and PGD parents had a shorter duration since the loss than non-PGD parents (MD = -3.26, P = 0.013). Conclusions: PGD is prevalent among Shidu parents. Grief counseling services for Shidu parents would be more effective if they target those who are mothers and have religious beliefs and those whose children died from accidents, lost children are older, and loss occurs more recently.
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Hijo Único , Trastorno de Duelo Prolongado , Niño , Estudios Transversales , Femenino , Humanos , Hijo Único/psicología , Padres/psicología , PrevalenciaRESUMEN
Since the end of 2019, coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide. The RNA genome of SARS-CoV-2, which is highly infectious and prone to rapid mutation, encodes both structural and nonstructural proteins. Vaccination is currently the only effective method to prevent COVID-19, and structural proteins are critical targets for vaccine development. Currently, many vaccines are in clinical trials or are already on the market. This review highlights ongoing advances in the design of prophylactic or therapeutic vaccines against COVID-19, including viral vector vaccines, DNA vaccines, RNA vaccines, live-attenuated vaccines, inactivated virus vaccines, recombinant protein vaccines and bionic nanoparticle vaccines. In addition to traditional inactivated virus vaccines, some novel vaccines based on viral vectors, nanoscience and synthetic biology also play important roles in combating COVID-19. However, many challenges persist in ongoing clinical trials.
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Vacunas contra la COVID-19 , COVID-19/prevención & control , Desarrollo de Vacunas , Humanos , SARS-CoV-2 , Desarrollo de Vacunas/tendencias , Vacunas de ARNmRESUMEN
Considering the limited sensitivity and accuracy of single-signal assay strategies, the multi-signal assay strategy has sparked significant excitement in recent years. In this study, for the first time, we reported a one-pot method in situ synthesis of carbon-containing nanoparticles (CNPs) via p-aminophenol (AP) and diethylenetriamine (DETA). The CNP solution exhibits yellow and light blue fluorescence under UV-light. Moreover, the CNPs exhibited excellent photoluminescence stability even under extreme conditions. Inspired by the alkaline phosphatase (ALP)-triggered specific catalytic reaction, we constructed an ultrasensitive fluorescence and colorimetric two-channel strategy for monitoring the ALP activity. By optimizing the detection parameters, the detection limits for both fluorometric and colorimetric were 0.05 mU mL-1. Moreover, the strategy showed high specificity and was successfully applied to monitor the ALP activity level in human serum samples. The analytical strategy opened a new window for the detection of the ALP activity, screening of the ALP inhibitor, and disease diagnosis.
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Fosfatasa Alcalina/sangre , Colorimetría , Colorantes Fluorescentes/química , Fluorometría , Nanopartículas/química , Fosfatasa Alcalina/antagonistas & inhibidores , Fosfatasa Alcalina/metabolismo , Inhibidores Enzimáticos/farmacología , Colorantes Fluorescentes/síntesis química , Humanos , Estructura Molecular , Tamaño de la PartículaRESUMEN
Alginate lyases show great potential for industrial and medicinal applications, especially as an attractive biocatalyst for the production of oligosaccharides with special bioactivities. A novel alginate lyase, AlyH1, from the marine bacterium Vibrio furnissii H1, which has been newly isolated from rotten seaweed, was purified and characterized. The purified enzyme showed the specific activity of 2.40 U/mg. Its molecular mass was 35.8 kDa. The optimal temperature and pH were 40 °C and pH 7.5, respectively. AlyH1 maintained stability at neutral pH (7.0-8.0) and temperatures below 30 °C. Metal ions Naâº, Mg2+, and K⺠increased the activity of the enzyme. With sodium alginate as the substrate, the Km and Vmax values of AlyH1 were 2.28 mg/mL and 2.81 U/mg, respectively. AlyH1 exhibited activities towards both polyguluronate and polymannuronate, and preferentially degraded polyguluronate. Products prepared from sodium alginate by AlyH1 were displayed to be di-, tri-, and tetra-alginate oligosaccharides. A partial amino acid sequence (190 aa) of AlyH1 analysis suggested that AlyH1 was an alginate lyase of polysaccharide lyase family 7. The sequence showed less than 77% identity to the reported alginate lyases. These data demonstrated that AlyH1 could be as a novel and potential candidate in application of alginate oligosaccharides production with low polymerization degrees.