RESUMEN
The supply of boron (B) alleviates the toxic effects of aluminum (Al) on root growth; however, the mechanistic basis of this process remains elusive. This study filled this knowledge gap, demonstrating that boron modifies auxin distribution and transport in Al-exposed Arabidopsis roots. In B-deprived roots, treatment with Al induced an increase in auxin content in the root apical meristem zone (MZ) and transition zone (TZ), whereas in the elongation zone (EZ) the auxin content was decreased beyond the level required for adequate growth. These distribution patterns are explained by the fact that basipetal auxin transport from the TZ to the EZ was disrupted by Al-inhibited PIN-FORMED 2 (PIN2) endocytosis. Experiments involving the modulation of protein biosynthesis by cycloheximide (CHX) and transcriptional regulation by cordycepin (COR) demonstrated that the Al-induced increase of PIN2 membrane proteins was dependent upon the inhibition of PIN2 endocytosis, rather than on the transcriptional regulation of the PIN2 gene. Experiments reporting on the profiling of Al3+ and PIN2 proteins revealed that the inhibition of endocytosis of PIN2 proteins was the result of Al-induced limitation of the fluidity of the plasma membrane. The supply of B mediated the turnover of PIN2 endosomes conjugated with indole-3-acetic acid (IAA), and thus restored the Al-induced inhibition of IAA transport through the TZ to the EZ. Overall, the reported results demonstrate that boron supply mediates PIN2 endosome-based auxin transport to alleviate Al toxicity in plant roots.
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Proteínas de Arabidopsis , Arabidopsis , Proteínas de Arabidopsis/metabolismo , Aluminio/toxicidad , Aluminio/metabolismo , Boro/metabolismo , Proteína 1 de Unión a Repeticiones Teloméricas/metabolismo , Raíces de Plantas/metabolismo , Ácidos Indolacéticos/metabolismo , Arabidopsis/metabolismoRESUMEN
The mechanistic basis by which boron (B) deprivation inhibits root growth via the mediation of root apical auxin transport and distribution remains elusive. This study showed that B deprivation repressed root growth of wild-type Arabidopsis seedlings, which was related to higher auxin accumulation (observed with DII-VENUS and DR5-GFP lines) in B-deprived roots. Boron deprivation elevated the auxin content in the root apex, coinciding with upregulation of the expression levels of auxin biosynthesis-related genes (TAA1, YUC3, YUC9, and NIT1) in shoots, but not in root apices. Phenotyping experiments using auxin transport-related mutants revealed that the PIN2/3/4 carriers are involved in root growth inhibition caused by B deprivation. B deprivation not only upregulated the transcriptional levels of PIN2/3/4, but also restrained the endocytosis of PIN2/3/4 carriers (observed with PIN-Dendra2 lines), resulting in elevated protein levels of PIN2/3/4 in the plasma membrane. Overall, these results suggest that B deprivation not only enhances auxin biosynthesis in shoots by elevating the expression levels of auxin biosynthesis-related genes but also promotes the polar auxin transport from shoots to roots by upregulating the gene expression levels of PIN2/3/4, as well as restraining the endocytosis of PIN2/3/4 carriers, ultimately resulting in auxin accumulation in root apices and root growth inhibition.
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Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Ácidos Indolacéticos/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Boro/metabolismo , Raíces de Plantas/metabolismoRESUMEN
Cobalt-ceria binary oxide nanojunctions were prepared by a sol-gel method with various chelating agents. The formed interfaces among CeO2 and Co3O4 can promote the generation of nucleophilic â¢O2- from O2 and then tune the catalytic oxidizability of the as-prepared CoCe nanojunctions. Given the results of HMF oxidations, malic acid as a complexing agent during the preparation process of the cobalt-ceria binary oxide nanojunctions can lead to a good catalytic performance on HMF oxidations to FDCA, and a remarkable FDCA selectivity of 92.3% and almost 100% HMF conversion were obtained at 110 °C under O2 and alkali conditions. By comparing the catalytic performance of the nanojunctions and physical mixing of cobalt-ceria binary oxide on oxidations of HMF, 5-hydroxymethyl-2-furancarboxylic acid (HFCA), and 5-formyl-2-furancarboxylic acid (FFCA), the interfaces intrinsically enhanced the FDCA yield dominantly via boosting the HMF oxidation to HFCA with â¢O2- during the stepwise oxidation of HMF to FDCA. It can be enlightening that the introduction of the active sites for transforming O2 to â¢O2- to promote the transformation of HMF into HFCA is the key to boosting the selective aerobic oxidation of HMF to FDCA.
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Bacterial resistance has led to increased interest in the use of antibacterial peptides (AMPs), but their clinical application is limited by poor stability and solubility, as well as complex cytotoxicity. Chemical modification is a common strategy to modulate AMPs. In this study, a de novo designed AMP (G3) was modified by adding an alkyl acid at the N-terminal and a monosaccharide at the C-terminal. Bio-activity assays demonstrated that conjugation with n-caprylic acid increased the peptide's antibacterial activity and permeabilized the membrane. Attachment of glucose or galactose at the C-terminal improved its biofilm inhibitory capacity and marginally reduced cytotoxicity. The hybrid peptide, containing both n-caprylic acid and galactose, exhibited excellent antibacterial and antibiofilm activity, as well as permeabilized the outer membrane.
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Péptidos Catiónicos Antimicrobianos , Galactosa , Péptidos Catiónicos Antimicrobianos/química , Glicosilación , Antibacterianos/farmacología , Antibacterianos/química , Pruebas de Sensibilidad MicrobianaRESUMEN
The commercial cationic surfactants (CSAa) with quaternary ammonium (QA) groups have proved to be broad-spectrum bactericide against bacteria, fungi, and viruses. Nevertheless, they inevitably exhibit potent irritation on the skin. In this work, we systematically investigated the regulatory mechanism of the host-guest supramolecular conformation with ß-cyclodextrin (ß-CD) on the bactericidal performance and skin irritation of CSAa with different head groups and chain lengths. When the ratio of incorporated ß-CD is not greater than 1:1, the bactericidal efficiency of CSAa@ß-CD (n > 12) remained above 90 % due to the free QA groups and hydrophobic fraction that can act on negatively charged bacterial membranes. And once the ratio of ß-CD exceeded 1:1, the ß-CD attracted to the bacterial surface by hydrogen bonding might prevent CSAa@ß-CD from acting on bacteria, resulting in a decrement in antibacterial performance. Even so, the antibacterial activity of CSAa with long alkyl chains (n = 16, 18) was independent from the complexation of ß-CD. Accordingly, both the zein solubilization assay and the neutrophil migration assay on zebrafish skin evidenced that ß-CD attenuated the interaction of surfactant with skin model proteins and the inflammatory effect on zebrafish, thereby enhancing skin mildness. In this way, we hope to create a simple but effective brainpower using the host-guest approach to guarantee both bactericidal efficiency and skin mildness without modifying the chemical structure of these commercial biocides.
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Compuestos de Amonio , Pez Cebra , Animales , Tensoactivos/farmacología , Tensoactivos/química , Conformación Molecular , Antibacterianos/farmacologíaRESUMEN
The broad-spectrum antimicrobial ability of de novo designed amphiphilic antimicrobial peptides (AMPs) G(IIKK)3I-NH2 (G3) and C8-G(IIKK)2I-NH2 (C8G2) have been demonstrated. Nonetheless, their potential as anti-quorum-sensing (anti-QS) agents, particularly against the opportunistic pathogen Pseudomonas aeruginosa at subinhibitory concentrations, has received limited attention. In this study, we proved that treating P. aeruginosa PAO1 with both AMPs at subinhibitory concentrations led to significant inhibition of QS-regulated virulence factors, including pyocyanin, elastase, proteases, and bacterial motility. Additionally, the AMPs exhibited remarkable capabilities in suppressing biofilm formation and their elimination rate of mature biofilm exceeded 95%. Moreover, both AMPs substantially downregulated the expression of QS-related genes. CD analysis revealed that both AMPs induced structural alterations in the important QS-related protein LasR in vitro. Molecular docking results indicated that both peptides bind to the hydrophobic groove of the LasR dimer. Notably, upon mutating key binding sites (D5, E11, and F87) to Ala, the binding efficiency of LasR to both peptides significantly decreased. We revealed the potential of antibacterial peptides G3 and C8G2 at their sub-MIC concentrations as QS inhibitors against P. aeruginosa and elucidated their action mechanism. These findings contribute to our understanding of the therapeutic potential of these peptides in combating P. aeruginosa infections by targeting the QS system.
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Péptidos Antimicrobianos , Pseudomonas aeruginosa , Pseudomonas aeruginosa/fisiología , Simulación del Acoplamiento Molecular , Percepción de Quorum , Biopelículas , Antibacterianos/farmacología , Antibacterianos/química , Proteínas Bacterianas/metabolismoRESUMEN
In this paper, a unified optimization model for medical image fusion based on tensor decomposition and the non-subsampled shearlet transform (NSST) is proposed. The model is based on the NSST method and the tensor decomposition method to fuse the high-frequency (HF) and low-frequency (LF) parts of two source images to obtain a mixed-frequency fused image. In general, we integrate low-frequency and high-frequency information from the perspective of tensor decomposition (TD) fusion. Due to the structural differences between the high-frequency and low-frequency representations, potential information loss may occur in the fused images. To address this issue, we introduce a joint static and dynamic guidance (JSDG) technique to complement the HF/LF information. To improve the result of the fused images, we combine the alternating direction method of multipliers (ADMM) algorithm with the gradient descent method for parameter optimization. Finally, the fused images are reconstructed by applying the inverse NSST to the fused high-frequency and low-frequency bands. Extensive experiments confirm the superiority of our proposed TDFusion over other comparison methods.
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GPR17 is a G-protein-coupled receptor (GPCR) implicated in the regulation of glucose metabolism and energy homeostasis. Such evidence is primarily drawn from mouse knockout studies and suggests GPR17 as a potential novel therapeutic target for the treatment of metabolic diseases. However, links between human GPR17 genetic variants, downstream cellular signaling, and metabolic diseases have yet to be reported. Here, we analyzed GPR17 coding sequences from control and disease cohorts consisting of individuals with adverse clinical metabolic deficits including severe insulin resistance, hypercholesterolemia, and obesity. We identified 18 nonsynonymous GPR17 variants, including eight variants that were exclusive to the disease cohort. We characterized the protein expression levels, membrane localization, and downstream signaling profiles of nine GPR17 variants (F43L, V96M, V103M, D105N, A131T, G136S, R248Q, R301H, and G354V). These nine GPR17 variants had similar protein expression and subcellular localization as wild-type GPR17; however, they showed diverse downstream signaling profiles. GPR17-G136S lost the capacity for agonist-mediated cAMP, Ca2+, and ß-arrestin signaling. GPR17-V96M retained cAMP inhibition similar to GPR17-WT, but showed impaired Ca2+ and ß-arrestin signaling. GPR17-D105N displayed impaired cAMP and Ca2+ signaling, but unaffected agonist-stimulated ß-arrestin recruitment. The identification and functional profiling of naturally occurring human GPR17 variants from individuals with metabolic diseases revealed receptor variants with diverse signaling profiles, including differential signaling perturbations that resulted in GPCR signaling bias. Our findings provide a framework for structure-function relationship studies of GPR17 signaling and metabolic disease.
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Síndrome Metabólico/genética , Mutación Missense , Receptores Acoplados a Proteínas G/genética , Transducción de Señal , Calcio/metabolismo , AMP Cíclico/metabolismo , Células HEK293 , Humanos , Transporte de Proteínas , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/metabolismo , beta-Arrestinas/metabolismoRESUMEN
Recent studies have proposed that heteromers of µ-opioid receptors (MORs) and galanin Gal1 receptors (Gal1Rs) localized in the mesencephalon mediate the dopaminergic effects of opioids. The present study reports converging evidence, using a peptide-interfering approach combined with biophysical and biochemical techniques, including total internal reflection fluorescence microscopy, for a predominant homodimeric structure of MOR and Gal1R when expressed individually, and for their preference to form functional heterotetramers when co-expressed. Results show that a heteromerization-dependent change in the Gal1R homodimeric interface leads to a switch in G-protein coupling from inhibitory Gi to stimulatory Gs proteins. The MOR-Gal1R heterotetramer, which is thus bound to Gs via the Gal1R homodimer and Gi via the MOR homodimer, provides the framework for a canonical Gs-Gi antagonist interaction at the adenylyl cyclase level. These novel results shed light on the intense debate about the oligomeric quaternary structure of G protein-coupled receptors, their predilection for heteromer formation, and the resulting functional significance.
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Analgésicos Opioides , Galanina , Analgésicos Opioides/farmacología , Mesencéfalo , Péptidos , Receptores OpioidesRESUMEN
A visible-light-induced persulfate-promoted cascade phosphorylation/cyclization reaction to access various phosphorylated pyrrolo[1,2-a]indolediones under mild conditions was developed. Notably, the transformation was carried out with diethyl carbonate/H2O as a green medium at room temperature. More impressively, traditional metal catalysts and photocatalysts could be effectively avoided. The reactions are simple to operate, easy to scale up, and have good functional group tolerance.
RESUMEN
Quorum sensing (QS) can regulate the pathogenicity of bacteria and the production of some virulence factors. It is a promising target for screening to find anti-virulence agents in the coming post-antibiotics era. Cyclo (L-Trp-L-Ser), one variety of cyclic dipeptides (CDPs), isolated from a marine bacterium Rheinheimera aquimaris, exhibited anti-QS activity against Chromobacterium violaceum CV026 and Pseudomonas aeruginosa PAO1. Unlike the CDPs composed of phenylalanine or tyrosine, the anti-QS activity has been widely studied; however, cyclo (L-Trp-L-Ser) and derivatives, containing one tryptophan unit and one non-aromatic amino acid, have not been systematically explored. Herein, the cyclo (L-Trp-L-Ser) and seven derivatives were synthesized and evaluated. All tryptophane-contained CDPs were able to decrease the production of violacein in C.violaceum CV026 and predicted as binding within the same pocket of receptor protein CviR, but in lower binding energy compared with the natural ligand C6HSL. As for P. aeruginosa PAO1, owning more complicated QS systems, these CDPs also exhibited inhibitory effects on pyocyanin production, swimming motility, biofilm formation, and adhesion. These investigations suggested a promising way to keep the tryptophan untouched and make modifications on the non-aromatic unit to increase the anti-QS activity and decrease the cytotoxicity, thus developing a novel CDP-based anti-virulence agent.
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Antibacterianos/farmacología , Dipéptidos/farmacología , Percepción de Quorum/efectos de los fármacos , Triptófano/química , Células A549 , Animales , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Biopelículas/efectos de los fármacos , Chromatiaceae/metabolismo , Chromobacterium/efectos de los fármacos , Dipéptidos/química , Dipéptidos/aislamiento & purificación , Humanos , Ratones , Células 3T3 NIH , Pseudomonas aeruginosa/efectos de los fármacos , Virulencia/efectos de los fármacosRESUMEN
The purposes are to explore the effect of Digital Twins (DTs) in Unmanned Aerial Vehicles (UAVs) on providing medical resources quickly and accurately during COVID-19 prevention and control. The feasibility of UAV DTs during COVID-19 prevention and control is analyzed. Deep Learning (DL) algorithms are introduced. A UAV DTs information forecasting model is constructed based on improved AlexNet, whose performance is analyzed through simulation experiments. As end-users and task proportion increase, the proposed model can provide smaller transmission delays, lesser energy consumption in throughput demand, shorter task completion time, and higher resource utilization rate under reduced transmission power than other state-of-art models. Regarding forecasting accuracy, the proposed model can provide smaller errors and better accuracy in Signal-to-Noise Ratio (SNR), bit quantizer, number of pilots, pilot pollution coefficient, and number of different antennas. Specifically, its forecasting accuracy reaches 95.58% and forecasting velocity stabilizes at about 35 Frames-Per-Second (FPS). Hence, the proposed model has stronger robustness, making more accurate forecasts while minimizing the data transmission errors. The research results can reference the precise input of medical resources for COVID-19 prevention and control.
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BACKGROUND AND AIMS: Glypican 3 (GPC3) is an oncofetal antigen involved in Wnt-dependent cell proliferation that is highly expressed in hepatocellular carcinoma (HCC). We investigated whether the functions of chimeric antigen receptors (CARs) that target GPC3 are affected by their antibody-binding properties. METHODS: We collected peripheral blood mononuclear cells from healthy donors and patients with HCC and used them to create CAR T cells, based on the humanized YP7 (hYP7) and HN3 antibodies, which have high affinities for the C-lobe and N-lobe of GPC3, respectively. NOD/SCID/IL-2Rgcnull (NSG) mice were given intraperitoneal injections of luciferase-expressing (Luc) Hep3B or HepG2 cells and after xenograft tumors formed, mice were given injections of saline or untransduced T cells (mock control), or CAR (HN3) T cells or CAR (hYP7) T cells. In other NOD/SCID/IL-2Rgcnull (NSG) mice, HepG2-Luc or Hep3B-Luc cells were injected into liver, and after orthotopic tumors formed, mice were given 1 injection of CAR (hYP7) T cells or CD19 CAR T cells (control). We developed droplet digital polymerase chain reaction and genome sequencing methods to analyze persistent CAR T cells in mice. RESULTS: Injections of CAR (hYP7) T cells eliminated tumors in 66% of mice by week 3, whereas CAR (HN3) T cells did not reduce tumor burden. Mice given CAR (hYP7) T cells remained tumor free after re-challenge with additional Hep3B cells. The CAR T cells induced perforin- and granzyme-mediated apoptosis and reduced levels of active ß-catenin in HCC cells. Mice injected with CAR (hYP7) T cells had persistent expansion of T cells and subsets of polyfunctional CAR T cells via antigen-induced selection. These T cells were observed in the tumor microenvironment and spleen for up to 7 weeks after CAR T-cell administration. Integration sites in pre-infusion CAR (HN3) and CAR (hYP7) T cells were randomly distributed, whereas integration into NUPL1 was detected in 3.9% of CAR (hYP7) T cells 5 weeks after injection into tumor-bearing mice and 18.1% of CAR (hYP7) T cells at week 7. There was no common site of integration in CAR (HN3) or CD19 CAR T cells from tumor-bearing mice. CONCLUSIONS: In mice with xenograft or orthoptic liver tumors, CAR (hYP7) T cells eliminate GPC3-positive HCC cells, possibly by inducing perforin- and granzyme-mediated apoptosis or reducing Wnt signaling in tumor cells. GPC3-targeted CAR T cells might be developed for treatment of patients with HCC.
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Carcinoma Hepatocelular/terapia , Glipicanos/metabolismo , Inmunoterapia Adoptiva , Neoplasias Hepáticas/terapia , Receptores Quiméricos de Antígenos/metabolismo , Linfocitos T/trasplante , Anciano , Anciano de 80 o más Años , Animales , Apoptosis , Carcinoma Hepatocelular/inmunología , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Proliferación Celular , Femenino , Regulación Neoplásica de la Expresión Génica , Glipicanos/genética , Glipicanos/inmunología , Granzimas/metabolismo , Células Hep G2 , Humanos , Neoplasias Hepáticas/inmunología , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Masculino , Ratones Endogámicos NOD , Ratones SCID , Persona de Mediana Edad , Perforina/metabolismo , Receptores Quiméricos de Antígenos/genética , Receptores Quiméricos de Antígenos/inmunología , Linfocitos T/inmunología , Linfocitos T/metabolismo , Carga Tumoral , Microambiente Tumoral , Vía de Señalización Wnt , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
We recently and for the first time reported that ethyl acetate extracts isolated from Penicillium chrysogenum DXY-1 exhibited anti-quorum sensing (anti-QS) activity. Herein, another active molecule in the extracts was identified as chrysin by NMR and MS. A 20 µg/mL dose of chrysin inhibited violacein production regulated by QS in C. violaceum CV026 by 31.6%. A 40 µg/mL dose of chrysin suppressed pyocyanin production, elastase activity, proteolytic activity, and biofilm formation regulated by QS in P. aeruginosa PA01 by 41.4%, 13.8%, 8.3%, and 42.4%, respectively. And chrysin could inhibit the swarming activity of P. aeruginosa PA01. Further, molecular docking and CD analysis were used to address the mechanism of chrysin's activity in C. violaceum. Molecular docking results revealed that chrysin suppresses QS system by competing with the natural signal molecule C6HSL for binding to the same pocket of CviR receptor. At the same time, CD results also showed that chrysin could change the secondary structure composition of CviR, which greatly prevented the binding of C6HSL/CviR, and further playing its role on inhibiting bacterial QS system. All these data demonstate that chrysin may be used as a potential QS inhibitor to tackle increasing drug resistance.
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Antibacterianos/farmacología , Chromobacterium/efectos de los fármacos , Flavonoides/farmacología , Penicillium chrysogenum/química , Pseudomonas aeruginosa/efectos de los fármacos , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Relación Dosis-Respuesta a Droga , Flavonoides/química , Flavonoides/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Estructura Molecular , Percepción de Quorum/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
At least 120 non-olfactory G-protein-coupled receptors in the human genome are 'orphans' for which endogenous ligands are unknown, and many have no selective ligands, hindering the determination of their biological functions and clinical relevance. Among these is GPR68, a proton receptor that lacks small molecule modulators for probing its biology. Using yeast-based screens against GPR68, here we identify the benzodiazepine drug lorazepam as a non-selective GPR68 positive allosteric modulator. More than 3,000 GPR68 homology models were refined to recognize lorazepam in a putative allosteric site. Docking 3.1 million molecules predicted new GPR68 modulators, many of which were confirmed in functional assays. One potent GPR68 modulator, ogerin, suppressed recall in fear conditioning in wild-type but not in GPR68-knockout mice. The same approach led to the discovery of allosteric agonists and negative allosteric modulators for GPR65. Combining physical and structure-based screening may be broadly useful for ligand discovery for understudied and orphan GPCRs.
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Alcoholes Bencílicos/química , Alcoholes Bencílicos/farmacología , Descubrimiento de Drogas , Lorazepam/química , Lorazepam/farmacología , Receptores Acoplados a Proteínas G/metabolismo , Triazinas/química , Triazinas/farmacología , Regulación Alostérica/efectos de los fármacos , Sitio Alostérico , Animales , Ansiolíticos/análisis , Ansiolíticos/química , Ansiolíticos/metabolismo , Ansiolíticos/farmacología , Alcoholes Bencílicos/análisis , Alcoholes Bencílicos/metabolismo , Condicionamiento Clásico , Miedo , Femenino , Células HEK293 , Humanos , Ligandos , Lorazepam/análisis , Lorazepam/metabolismo , Masculino , Memoria/efectos de los fármacos , Ratones , Ratones Noqueados , Modelos Moleculares , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/deficiencia , Transducción de Señal/efectos de los fármacos , Triazinas/análisis , Triazinas/metabolismoRESUMEN
One new spirocyclic lactone, terreinlactone C (1), and one new benzopyran derivative, 2,2-dimethyl-3-hydroxychroman-6-aldehyde (2), were discovered from the fungus Aspergillus terreus. The chemical structures of compounds 1 and 2 were elucidated by detailedly analyzing NMR and HRESIMS data. Compound 1 is the first natural product with a 1-oxaspiro[4.5]decan-2-one ring system and a possible biogenetic pathway is proposed. Two compounds were tested for their cytotoxic activities against five human cancer cell lines.[Formula: see text].
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Benzopiranos , Lactonas , Aspergillus , Benzopiranos/farmacología , Lactonas/farmacología , Estructura MolecularRESUMEN
Two novel water-soluble fluorescence probes T1 and T2 based on 5(6)-carboxyl rhodamine were designed and synthesized using a regioselective reaction. The probes exhibited highly selective and sensitive recognition toward Cu2+ over other metal ions in acetonitrile/Tris-HCl buffer solution (2:98, v/v; pH 7.4). Detection limits were 0.4 µM for T1 and 4.50 µM for T2 based on fluorescence titration analysis. Furthermore, probe T1 was successfully applied in cell imaging experiments to monitor Cu2+ in cells.
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Colorantes Fluorescentes , Agua , Cobre , Humanos , Imagen Óptica , RodaminasRESUMEN
Phelligridin LA (PLA) is a natural product with vigorous free radical scavenging activities accumulated in the liquid fermentation of herbal medicinal fungus Inonotus baumii. Aiming to establish an efficient isolation method of PLA from the fermentation broth, we evaluated the adsorption of PLA by macroporous resins. The best resin ADS-17 was screened for six candidates with various physical properties and adsorption behaviors. Studies on the thermodynamics and kinetics of the process revealed that the adsorption reaction could take place spontaneously, which implied that the heat generated in adsorption might compensate for the decrease in entropy. The Freundlich theory could be utilized to fit the experimental data. The pseudo-second-order equation could describe the process, and the adsorption rate was primarily controlled by liquid film diffusion and pore diffusion. The influencing operation factors (temperature, pH, and the ratio of fermentation broth to resin) of the adsorption process were optimized with response surface methodology. The optimized condition (temperature 22.81 °C, pH 5.19, and the ratio of fermentation broth to resin or RLS 5.11) supported an adsorption rate of 97.03%. These findings would be indispensable for further optimization of the efficient separation of PLA from the fermentation broth, and the fermentation production of PLA in which separation would be included.
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Antioxidantes/química , Basidiomycota/metabolismo , Biotecnología/métodos , Fermentación , Resinas Sintéticas/química , Adsorción , Difusión , Entropía , Concentración de Iones de Hidrógeno , Microbiología Industrial/métodos , Cinética , Porosidad , Temperatura , Termodinámica , Factores de TiempoRESUMEN
The phelligridin LA was one of the valuable metabolites synthesized by the medicinal fungus Sanghuang in liquid fermentation. In the improvement of PLA productivity by fermentation, we investigated the optimal conditions for the efficient separation of PLA from the fermentation broth with a chromatographic column packed with the macroporous resin ADS-17. Based on the findings, we further developed an integrated bioreactor system that coupled the fermentation and separation of PLA. Fermentation experiments with the bioreactor system testified the performance of our design in fortification of the PLA production: an improvement of PLA production by 2.14 folds was successfully achieved due to the prompt removal of the PLA, while the formation of hyphae biomass was not affected. Also, the integrated system could afford a simultaneous purification of PLA to a purity of 92.95% with a recovery of 84.3%, which was comparable to that of the PLA purified with an additional process (97.53%), at a reasonable recovery. This study provided a feasible approach for the improved production of PLA by fermentation. Besides, the design of the integrated bioreactor system offered a useful reference for the fermentation process development of fungi for the production of diverse valuable metabolites.
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Fermentación , Inonotus/metabolismo , Adsorción , Reactores Biológicos , Medios de CultivoRESUMEN
Two-dimensional arrays of nanoparticles (NPs) have widespread applications in optical coatings, plasmonic sensors, and nanocomposites. Current bottom-up approaches that use homogeneous NP templates, such as silane self-assembled monolayers or homopolymers, are typically plagued by NP aggregation, whereas patterned block copolymer (BCP) films require specific compositions for specific NP distributions. Here, we show, using polystyrene- b-poly(4-vinylpyridine) (PS- b-P4VP) and gold NPs (AuNPs) of various sizes, that a nanothin PS- b-P4VP brushlike coating (comprised of a P4VP wetting layer and a PS overlayer), which is adsorbed onto flat substrates during their immersion in very dilute PS- b-P4VP tetrahydrofuran solutions, provides an excellent template for obtaining dense and well-dispersed AuNPs with little aggregation. These non-close-packed arrays have similar characteristics regardless of immersion time in solution (about 10-120 s studied), solution concentration below a critical value (0.1 and 0.05 mg/mL studied), and AuNP diameter (10-90 nm studied). Very dilute BCP solutions are necessary to avoid deposition, during substrate withdrawal, of additional material onto the adsorbed BCP layer, which typically leads to patterned surfaces. The PS brush coverage depends on immersion time (adsorption kinetics), but full coverage does not inhibit AuNP adsorption, which is attributed to PS molecular rearrangement during exposure to the aqueous AuNP colloidal solution. The simplicity, versatility and robustness of the method will enable applications in materials science requiring dense, unaggregated NP arrays.