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Fluorescent RNAs (FRs) provide an attractive approach to visualizing RNAs in live cells. Although the color palette of FRs has been greatly expanded recently, a green FR with high cellular brightness and photostability is still highly desired. Here we develop a fluorogenic RNA aptamer, termed Okra, that can bind and activate the fluorophore ligand ACE to emit bright green fluorescence. Okra has an order of magnitude enhanced cellular brightness than currently available green FRs, allowing the robust imaging of messenger RNA in both live bacterial and mammalian cells. We further demonstrate the usefulness of Okra for time-resolved measurements of ACTB mRNA trafficking to stress granules, as well as live-cell dual-color superresolution imaging of RNA in combination with Pepper620, revealing nonuniform and distinct distributions of different RNAs throughout the granules. The favorable properties of Okra make it a versatile tool for the study of RNA dynamics and subcellular localization.
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BACKGROUND: The steam processing characteristics of chicken are a key factor in the simplicity and versatility of steamed chicken dishes. The aim of this study was to investigate in depth the changes in tenderness and water retention of marinated chicken at different slow steaming endpoint temperatures, and to further explore the effect of the evolution of protein conformations on the water status. RESULTS: The results showed that chicken samples' shear force peaked at 80 °C and decreased rapidly at 90 °C. As the steaming endpoint temperature increased between 50 and 90 °C, T21, T22, moisture content and centrifugal loss decreased, but P21, P22 and myofibril water-holding capacity showed regular changes. The electrophoretic bands and protein conformation changes showed that protein in marinated chicken underwent different degrees of denaturation, degradation and aggregation. And at 70 °C, with an increase of hydrophobic groups and crosslinking of disulfide bonds as well as an increase in the number of denatured sarcoplasmic proteins, the intermolecular network was enhanced, thus affecting the water retention. CONCLUSION: Water status of chicken meat heated at different steaming temperatures is closely related to the evolution of protein conformations. The present study serves as a robust theoretical foundation for enhancing the quality of steamed chicken products at an industrial scale. © 2024 Society of Chemical Industry.
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Pollos , Culinaria , Carne , Vapor , Agua , Animales , Agua/análisis , Agua/química , Carne/análisis , Calor , Temperatura , Manipulación de Alimentos/métodosRESUMEN
Aberrant protein post-translational modification is a hallmark of malignant tumors. Lysine succinylation (Ksucc) plays a vital role in cell energy metabolism in various cancers. However, whether succinylation can be catalyzed by acetyltransferase p300 remains unclear. In this study, we unveiled that p300 is a "writer" for succinylation, and p300-mediated Ksucc promotes cell glycometabolism in lung adenocarcinoma (LUAD). Specifically, our succinylome data revealed that EP300 deficiency leads to the systemic reduction of Ksucc, and 79.55% of the p300-succinylated proteins were found in the cytoplasm, which were primarily enriched in the carbohydrate metabolism process. Interestingly, deleting EP300 led to a notable decrease in Ksucc levels on several glycolytic enzymes, especially Phosphoglycerate Kinase 1 (PGK1). Mutation of the succinylated site of PGK1 notably hindered cell glycolysis and lactic acid excretion. Metabolomics in vivo indicated that p300-caused metabolic reprogramming was mainly attributed to the altered carbohydrate metabolism. In addition, 89.35% of LUAD patients exhibited cytoplasmic localization of p300, with higher levels in tumor tissues than adjacent normal tissues. High levels of p300 correlated with advanced tumor stages and poor prognosis of LUAD patients. Briefly, we disclose the activity of p300 to catalyze succinylation, which contributes to cell glucose metabolic reprogramming and malignant progression of lung cancer.
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Adenocarcinoma del Pulmón , Proteína p300 Asociada a E1A , Neoplasias Pulmonares , Humanos , Adenocarcinoma del Pulmón/genética , Glucosa , Neoplasias Pulmonares/genética , Reprogramación Metabólica , Proteína p300 Asociada a E1A/genéticaRESUMEN
Fluorescent RNAs, aptamers that bind and activate small fluorogenic dyes, have provided a particularly attractive approach to visualizing RNAs in live cells. However, the simultaneous imaging of multiple RNAs remains challenging due to a lack of bright and stable fluorescent RNAs with bio-orthogonality and suitable spectral properties. Here, we develop the Clivias, a series of small, monomeric and stable orange-to-red fluorescent RNAs with large Stokes shifts of up to 108 nm, enabling the simple and robust imaging of RNA with minimal perturbation of the target RNA's localization and functionality. In combination with Pepper fluorescent RNAs, the Clivias enable the single-excitation two-emission dual-color imaging of cellular RNAs and genomic loci. Clivias can also be used to detect RNA-protein interactions by bioluminescent imaging both in live cells and in vivo. We believe that these large Stokes shift fluorescent RNAs will be useful tools for the tracking and quantification of multiple RNAs in diverse biological processes.
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Aptámeros de Nucleótidos , Colorantes Fluorescentes , ARN , Microscopía Fluorescente , Aptámeros de Nucleótidos/genéticaRESUMEN
Hydrogel materials show promise for diverse applications, particular as biocompatible materials due to their high water content. Despite advances in hydrogel technology in recent years, their application is often severely limited by inadequate mechanical properties and time-consuming fabrication processes. Here we report a rapid hydrogel preparation strategy that achieves the simultaneous photo-crosslinking and establishment of biomimetic soft-hard material interface microstructures. These biomimetic interfacial-bonding nanocomposite hydrogels are prepared within seconds and feature clearly separated phases but have a strongly bonded interface. Due to effective interphase load transfer, biomimetic interfacial-bonding nanocomposite gels achieve an ultrahigh toughness (138 MJ m-3) and exceptional tensile strength (15.31 MPa) while maintaining a structural stability that rivals or surpasses that of commonly used elastomer (non-hydrated) materials. Biomimetic interfacial-bonding nanocomposite gels can be fabricated into arbitrarily complex structures via three-dimensional printing with micrometre-level precision. Overall, this work presents a generalizable preparation strategy for hydrogel materials and acrylic elastomers that will foster potential advances in soft materials.
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SMAD-specific E3 ubiquitin protein ligase 2 (SMURF2) functions as either a tumor promoter or tumor suppressor in several tumors. However, the detailed effect of SMURF2 on non-small cell lung cancer has not been fully understood. In this study, SMURF2 expression and its diagnostic value were analyzed. Co-Immunoprecipitation (Co-IP), proximity ligation assay (PLA), chromatin immunoprecipitation (ChIP) and nude mice tumor-bearing model were applied to further clarify the role of SMURF2 in lung cancer. SMURF2 expression was reduced in the tumor tissues of patients with NSCLC and high SMURF2 expression was significantly correlated with favorable outcomes. Furthermore, the overexpression of SMURF2 significantly inhibited lung cancer cell progression. Mechanistically, SMURF2 interacted with inhibitor of DNA binding 2 (ID2), subsequently promoting the poly-ubiquitination and degradation of ID2 through the ubiquitin-proteasome pathway. Downregulated ID2 in lung cells dissociates endogenous transcription factor E2A, a positive regulator of the cyclin-dependent kinase inhibitor p21, and finally induces G1/S arrest in lung cancer cells. This study revealed that the manipulation of ID2 via SMURF2 may control tumor progression and contribute to the development of novel targeted antitumor drugs.
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Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Animales , Ratones , Carcinoma de Pulmón de Células no Pequeñas/genética , Proliferación Celular/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Ratones Desnudos , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación , HumanosRESUMEN
p300 acts as a transcription coactivator and an acetyltransferase that plays an important role in tumourigenesis and progression. In previous studies, it has been confirmed that p300 is an important regulator in regulating the evolution of malignant tumours and it also has extensive functions. From the perspective of non-posttranslational modification, it has been proven that p300 can participate in regulating many pathophysiological processes, such as activating oncogene transcription, promoting tumour cell growth, inducing apoptosis, regulating immune function and affecting embryo development. In recent years, p300 has been found to act as an acetyltransferase that catalyses a variety of protein modification types, such as acetylation, propanylation, butyylation, 2-hydroxyisobutyration, and lactylation. Under the catalysis of this acetyltransferase, it plays its crucial tumourigenic driving role in many malignant tumours. Therefore, the function of p300 acetyltransferase has gradually become a research hotspot. From a posttranslational modification perspective, p300 is involved in the activation of multiple transcription factors and additional processes that promote malignant biological behaviours, such as tumour cell proliferation, migration, and invasion, as well as tumour cell apoptosis, drug resistance, and metabolism. Inhibitors of p300 have been developed and are expected to become novel anticancer drugs for several malignancies. We review the characteristics of the p300 protein and its functional role in tumour from the posttranslational modification perspective, as well as the current status of p300-related inhibitor research, with a view to gaining a comprehensive understanding of p300.
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Neoplasias , Factores de Transcripción , Humanos , Acetilación , Neoplasias/genética , Procesamiento Proteico-PostraduccionalRESUMEN
We used a high-fat diet (HFD) and streptozotocin (STZ) to induce type 2 diabetic mellitus (T2DM) mice and evaluated the effect of banana peel dietary fibers (BP-DFs) as potential hypoglycemic agents. After 5 weeks of intervention with banana peel dietary fibers (BP-DFs), food intake was reduced, body weight was increased, blood lipids and glucose were reduced, fasting insulin and GLP-1 levels were increased, and liver and pancreatic tissue damage was reduced. Banana peel soluble dietary fiber (BP-SDF) has the most significant effect. The results of fecal microbiota analysis showed that BP-DFs could ameliorates gut microbiome dysbiosis, and all three types of dietary fibers have obvious effects. The results of fecal short-chain fatty acids (SCFAs) showed that the content of fecal SCFAs was increased after BP-DFs dietary intervention, and BP-SDF had the most obvious effect. RT-PCR experiment results show that BP-DFs can up-regulate the mRNA expression levels of PI3K, AKT, IRS-1, and FOXO1 in the liver of diabetic mice, which indicates that BD-DFs may play a role in improving insulin resistance and insulin signal transduction via the IRS/PI3K/AKT pathway, improving insulin resistance and insulin signal transduction. Our research may be extended to BP-DFs, especially BP-SDF, as the basis for potential dietary intervention to prevent or treat type 2 diabetic mellitus. This work supports future research studies of the anti-diabetic properties of BP-SDF in humans. PRACTICAL APPLICATIONS: Diabetes can lead to a variety of complications that have a huge impact on health. Dietary fiber may help in lowering blood sugar. Our experimental results showed that banana peel dietary fibers have the effect of reducing food intake, blood sugar, improving liver and pancreas function, increasing the abundance of intestinal flora, and improving the IRS/PI3K/AKT pathway in T2DM mice. Therefore, this study could provide a theoretical basis for the development of functional foods with banana peel dietary fiber.
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Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Resistencia a la Insulina , Musa , Animales , Glucemia , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Dieta Alta en Grasa , Fibras de la Dieta , Péptido 1 Similar al Glucagón , Glucosa , Humanos , Hipoglucemiantes/farmacología , Insulina , Lípidos , Ratones , Musa/metabolismo , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , ARN Mensajero , EstreptozocinaRESUMEN
Bovistella sinensis (BS) Lloyd was medically used by Chinese folks and associated with various bioactivities. In this study, dry fruiting body of Bovistella sinensis (BS) Lloyd was self-fermented to improve the anti-breast-cancer activity and the mitochondrial ROS-induced apoptosis of key compound was investigated. BS extracts obtained with petroleum ether, ethyl acetate, n-butanol, ethanol, and distilled water showed various inhibitory effects on the proliferation of MDA-MB-231. The various self-fermented BS extracts had a better effect on inhibition of MDA-MB-231 proliferation than that of untreated. And the ethyl acetate extract was found having the highest inhibitory effect on MDA-MB-231 proliferation, which was further separated into seven fractions. And among these fractions, fraction 6 exhibited the highest performance, where the major component F was obtained. The inhibition rate of 50 µg/ml of component F on MDA-MB-231, MCF-7, and MCF-10A were 60.12%, 56.16%, and 6.45%, respectively, showed the low toxicity in normal cell line. When treated with F, the activity and the mitochondrial membrane potential of MDA-MB-231 cells decreased significantly, while the intracellular reactive oxygen species increased, showed that the mitochondrial pathway was induced by reactive oxygen species. The HPLC, 1 H NMR, 13 C NMR, and 2D NMR analysis showed component F may be a kind of fatty acid or ester. Therefore, self-fermentation may be an efficient technology that could improve anti-tumor activity and component F from self-fermented BS might be considered as an anti-cancer ingredient applied in functional food and anti-carcinogen. PRACTICAL APPLICATIONS: Anti-breast-cancer activity and mechanism of self-fermented Bovistella sinensis Lloyd extract were investigated. The ethyl acetate extract showed a comparatively higher inhibitory effect and was separated into seven fractions. Fraction 6 showed the strongest cytotoxic activity against MDA-MB-231 breast cancer cell line and obtained a major component F with low cytotoxicity in a normal cell line. Component F had the potential to be used as natural anti-cancer agents.
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Antineoplásicos , Neoplasias de la Mama , Antineoplásicos/farmacología , Apoptosis , Neoplasias de la Mama/tratamiento farmacológico , Proliferación Celular , Femenino , Humanos , Extractos Vegetales/química , Extractos Vegetales/farmacología , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Puffballs are a class of fungi widely distributed worldwide and associated with various bioactivities. This research mainly showed the antitumor bioactivity of extracts from Calvatia lilacina (CL), which is a common variety of puffballs. NMR and high-performance liquid chromatography methods are used to characterize the extracts. Results showed that CL extracts obtained with petroleum ether, ethyl acetate, ethanol, and water elicited obvious inhibitory effects on the proliferation of A549, Caco-2, and MDA-MB-231. Among these extracts, petroleum ether extract demonstrated the highest performance. This extract was then separated into seven sub-fractions (SFs). Three of these SFs (3#, 6#, and 7#) induces a decrease in the viability of MDA-MB-231 cells in which 7# SF exhibited the highest cytotoxicity, where the major component was found to be ergosta-7,22-dien-3-one. Further tests revealed that 7# SF from petroleum ether extract could trigger severe cell death in human breast cancer cells (MDA-MB-231) by activating the apoptotic pathway dependent on mitochondrial reactive oxygen species and caspase activation. All these results in combination indicate that the mechanism of extract-potentiated apoptosis associates closely with ROS-dependent mitochondrial dysfunction events which further induces mitochondria-mediated intrinsic cytochrome C-caspase-related pathway of apoptosis.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.1936576.
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Agaricales , Neoplasias de la Mama , Apoptosis , Neoplasias de la Mama/patología , Células CACO-2 , Caspasas/metabolismo , Muerte Celular , Línea Celular Tumoral , Proliferación Celular , Femenino , Humanos , Potencial de la Membrana Mitocondrial , Mitocondrias , Extractos Vegetales/química , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Present study aims to investigate the combined effect of anticancer drug, norcantharidin (NCTD) in combination with glycolytic inhibitor, i.e. 2-deoxy-d-glucose (2-DG) in liver cancer (HepG2 and Hepa 1-6) cells. Cell viability of NCTD and 2-DG exposed cells was determined by MTT assay, whereas, colony-forming efficiency and migration rate was determined by clonogenic assay and wound healing assay, respectively. Nuclear DAPI staining and Annexin V FITC-PI staining were used to study the apoptosis induction in cells. Fluorescence microscopy imaging was performed to detect the intracellular reactive oxygen species (ROS) generation and mitochondrial membrane potential by staining with DCFDA and JC-1 dye, respectively. Cell viability assay revealed that NCTD and 2-DG exposure in combination displays more cytotoxic effect than a single drug. Additionally, cells lose their colony formation efficiency, as well as the reduced migration rate ability was also observed upon combined exposure. Increased nuclear condensation and mitochondrial membrane depolarization are considered as key features for apoptosis induction in cancerous cells. Furthermore, oxidative stress produced in cells due to enhanced intracellular ROS generation is also major probability for cellular damage. Thus, from the initial data it can be concluded that further preclinical studies will be needed to prove the efficacy of NCTD and 2-DG in hepatocellular carcinoma therapy.
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BACKGROUND: Artificial intelligence (AI) technology has been incorporated into all walks of life, especially the integration of machine learning and health management has achieved very significant progress and results. It is very necessary to analyze personalized sports health management services and long-term assessment of health issues in the era of AI. METHODS: This paper explores AI + personalized sports management service system design ideas, system operation process, management stage design, taking common chronic diseases, and diabetes as examples. 150 patients were divided into an observation group and a control group, and the blood glucose, blood pressure, blood lipid, and knowledge awareness rate were compared. RESULTS: The blood glucose, blood pressure, and blood lipid levels of the observation group all reduced, and the awareness rate of diabetes knowledge increased, which proved that the AI research has great value in sports rehabilitation research coupled with long term health assessment and is worth further research. CONCLUSION: The AI research proposed in this paper is of far-reaching practical significance in helping the transformation and upgrading of the sports health management service industry, promoting the innovative development of sports health management service supply, and promoting national fitness and national health.
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Inteligencia Artificial , Traumatismos en Atletas/rehabilitación , Deportes , Anciano , China , Biología Computacional , Diabetes Mellitus/fisiopatología , Diabetes Mellitus/terapia , Femenino , Humanos , Aprendizaje Automático , Masculino , Persona de Mediana Edad , Medicina de Precisión/métodos , Medicina de Precisión/estadística & datos numéricos , Medicina Deportiva/métodos , Medicina Deportiva/organización & administración , Medicina Deportiva/estadística & datos numéricosRESUMEN
BACKGROUND: To evaluate the antimicrobial and microbicidel activity of B. radicata fermentation broth, the broth was purified by DEAE-cellulose and sephadex LC-20 column. The compounds were submitted to spectral analyses (HPLC, FT-IR, 1D and 2D NMR etc.). RESULTS: The purified compounds were identified as the Griseococcin(s) which were naphthoquinone derivatives, the Chemical formula and MW of Griseococcin (1) was determined as C37O10H43N and 661 Da. only Griseococcin (1) has good antimicrobial activity among the Griseococcin(s). The zone of inhibition (ZOI), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) or minimum fungicidal concentration (MFC) of Griseococcin (1) were used to investigate the antimicrobial activity. Antifungal activity of Griseococcin (1) was significant, especially for main pathogenic fungus Trichophyton rubrum and Trichophyton mentagrophytes, MFC/MIC of Griseococcin (1) was 1, while MFC/MIC of postive control was greater than 4, the fungicidal effect of Griseococcin (1) was better than that of positive control. CONCLUSIONS: In this paper, the secondary metabolite compound Griseococcin (1) from B. radicata was purified. The purified compound can restrain main pathogens (T. rubrum and T. mentagrophytes) leading to tinea pedis. The antifungal activity of Griseococcin (1) was similar to that of the positive control and the fungicidal effect of Griseococcin (1) was better than that of positive control, it might be suitable for pharmaceutical industries.
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Agaricales/química , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Agaricales/metabolismo , Antibacterianos/química , Antifúngicos/aislamiento & purificación , Arthrodermataceae/efectos de los fármacos , Bacterias/efectos de los fármacos , Cromatografía Líquida de Alta Presión , Evaluación Preclínica de Medicamentos , Fermentación , Hongos/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Metabolismo Secundario , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Banana (Musa nana Lour.) have the effect of anti-obesity and lipid modulating properties. However, the influences of banana pulp dietary fibers (BP-DF) on metabolic syndrome (MetS) and gut microbiota (GM) are unknown. In this research, we explore a novel strategy for dietary BP-DF on attenuation of lipid metabolic disease, GM disorder, and associated mechanisms in high-fat diet (HFD) mice. BP-DF can strongly suppress on HFD caused body weight and epididymal fat mass gain, and significantly improved serum lipid profiles, liver lipid profiles, and intestinal function. BP-DF also significantly improved fecal short-chain fatty acids formation and fecal ammonia content. BP-DF impacted the intestinal microorganism at all kinds of taxonomic levels by increasing the proportions of beneficial Lactobacillus, Bacteroidales _S24_7_group, and Alloprevotella and decreasing the disease or obesity associated Sutterella, Streptococcaceae, and Erysipelotrichaceae. The experiments show that BP-DF may use as a functional ingredient for preventing obesity, MetS, and intestinal microorganism imbalance. PRACTICAL APPLICATIONS: Obesity result in many metabolic complications, and it poses a great threat to people's health. Nowadays, the introduction of DF may lead to the development of a new strategy in the treatment of obesity and its metabolic syndrome. Our experiments findings show that BP-DF may use as a functional ingredient for preventing obesity, MetS, and intestinal microorganism imbalance. Therefore, BP-DF can be applied to the development and production of functional food, and can also be used as an important food functional ingredient, which can be added to various food, such as bread, noodles, baked goods, cakes, etc., to improve its nutritional value.
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Microbioma Gastrointestinal , Síndrome Metabólico , Musa , Animales , Dieta Alta en Grasa/efectos adversos , Fibras de la Dieta , Síndrome Metabólico/etiología , Síndrome Metabólico/prevención & control , RatonesRESUMEN
In this study, the preparation of molecularly imprinted polymers for bilobalide (BBMIPs) was successfully achieved by bulk polymerization with methacrylamide (MAM), trimethylolpropane triacrylate (TMPTA), and acetonitrile (ACN) as functional monomer, cross-linker, and solvent, respectively. After Gaussian software simulation and single factor experiments, the prepared MIPs with a molar ratio of 1:4:15 for BB-MAM-TMPTA were systematically characterized. The hydrogen bonding interaction between BB and MAM was confirmed by a combination of FTIR and NMR analysis. Thermal gravimetric analysis results displayed that MIPs have excellent thermal stability under high temperature. Additionally, the average pore size and surface area of MIPs were found to be higher than those of NIPs through nitrogen adsorption results. The results of static adsorption and kinetic adsorption suggested that the adsorption equilibrium concentration was 0.6 mg/mL and the equilibrium time was 5 h, and the Langmuir and pseudo-second-order kinetic models were proven to fit with static and kinetic adsorption behaviors, respectively. Meanwhile, the selective adsorption study revealed that MIPs show high adsorption and great selectivity towards BB in comparison with other substances having similarly structure. MIPs also possessed a good performance on reusability, maintaining a high recovery rate after being reused 5 times. The application experiment further indicated that MIPs can effectively separate BB from low purity samples. Therefore, the prepared MIPs had a great potential for BB separation.
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BACKGROUND: To test the antimicrobial activity of different extracts and fermentation broth from puffball(Bovistella radicata), the different extracts and fermentation broth of puffball were prepared, the active fraction was investigated by UPLC-UV-MS and semi-preparative chromatograph. RESULTS: Through zones of inhibition (ZOI) and minimum inhibitory concentrations (MIC) tests, the supernatant of fermentation possessed best antimicrobial activity in all extracts whose MIC value is 31.2 µg/ml against T. rubrum, T. mentagrophytes, S. aureus and P. aeruginosa. And ZOI value is 29.01, 21.02, 35.02, 28.01 mm against T. rubrum, T. mentagrophytes, S. aureus and P. aeruginosa. Then we compare the puffball fermentation supernatant with blank contrast by LC-MS. There are the characteristic peaks named PBR-1 and PBR-2 with the puffball fermentation supernatant, the separation of compound PBR-1 and PBR-2 was done on semi-preparative C18 column and the MIC and ZOI of compound PBR-1 and PBR-2 are 15.6 µg/ml and 34 mm with the antifungal test. CONCLUSIONS: The fermentation supernatant and compound PBR-1 and PBR-2 have promising antifungal activity against T. rubrum and T. mentagrophytes.
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OBJECTIVE: In order to improve the rate of the heterotrophic nitrification, we screened and identified a high-efficient heterotrophic nitrifier, as well as studied its nitrification characteristics and nitrification conditions. METHODS: We obtained activated sludge samples from sewage and chemical fertilizer factories and farmland. We then utilized sodium citrate and ammonium chloride as carbon and nitrogen source. We used methods including domestication, gradient dilution of domestication liquid, isolation from streaking plate and color indicator as rapid nitrification detection. Finally a high-efficient heterotrophic nitrifier was obtained. We identified this strain according to its physiological, biochemical properties and the sequence analysis of 16S rDNA. After inoculating the strain into artificial ammonia-nitrogen wastewater, changes of nitrogen compounds were measured in order to understand the nitrification characteristics. Nitrification condition was also optimized by changing the carbon source, dissolved oxygen, C/N ratio, temperature and pH of the medium. RESULTS: The heterotrophic nitrifier was a gram-negative bacilli. It neither fermented glucose, nor produced indole. Oxidase and catalase tests were positive. It could produce alkali if organic salt was provided. The strain shared 99.7% sequence identity of its 16S rDNA with ES-SDK-3 of Alcaligenes sp. In the artificial wastewater with 182.30 mg/L ammonia nitrogen as initial concentration, the removal efficiency by the strain was 99. 8% after 30h cultivation. The average nitrogen removal rate was 9. 61 mg-N/L/h in its exponential phase. It produced almost no NO(2-)-N and NO(3-)-N in the entire nitrification process. The optimal carbon source is sodium citrate. Higher dissolved oxygen and C/N ratio favor its nitrification. When temperature is ranged from 30 degrees C to 35 degrees C and pH is ranged from 5.0 to 9.0, it can completely remove ammonia nitrogen. CONCLUSIONS: The strain was identified as Alcaligenes genus, and named as Alcaligenes sp. HN-S. Our research confirmed that the Alcaligenes sp. HN-S had significant advantages over heterotrophic nitrifiers that were screened previously with aspect of ammonia nitrogen removal rate. The research of its nitrification condition definitely provided necessary theory support for a new biology process to remove nitrogen with high efficiency.