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1.
Bioresour Technol ; : 126050, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34597803

RESUMO

ß-Alanine is the only naturally occurring ß-amino acid, widely used in the fine chemical and pharmaceutical fields. In this study, metabolic design strategies were attempted in Escherichia coli W3110 for enhancing ß-alanine biosynthesis. Specifically, heterologous L-aspartate-α-decarboxylase was used, the aspartate kinase I and III involved in competitive pathways were down-regulated, the ß-alanine uptake system was disrupted, the phosphoenolpyruvate carboxylase was overexpressed, and the isocitrate lyase repressor repressing glyoxylate cycle shunt was delete, the glucose uptake system was modified, and the regeneration of amino donor was up-regulated. On this basis, a plasmid harboring the heterologous panD and aspB was constructed. The resultant strain ALA17/pTrc99a-panDBS-aspBCG could yield 4.20 g/L ß-alanine in shake flask and 43.94 g/L ß-alanine (a yield of 0.20 g/g glucose) in 5-L bioreactor via fed-batch cultivation. These modification strategies were proved effective and the constructed ß-alanine producer was a promising microbial cell factory for industrial production of ß-alanine.

2.
Microvasc Res ; 139: 104263, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34655603

RESUMO

Cannabinoids are reported to regulate cardiovascular functions. Cannabinoid receptors 1 (CB1Rs) are widely expressed in both the neuronal system and vascular system, but the contribution of CB1Rs in vascular smooth muscle (CB1RSM) to cardiovascular functions is not clear yet. In this research, we analyzed the effects of CB1RSM on blood pressure, vasoconstriction, and vasodilation abilities by using conditionally CB1R knockout mice (CB1RSMKO). The results show no significant difference in basal blood pressure between the conscious CB1RSMKO and control mice, indicating that CB1RSM is not essential for basal blood pressure maintenance. The constriction of the CB1RSMKO mesenteric artery in vitro was not significantly altered compared with that of the control mice. In contrast, the relaxation to CB1R agonist 2-AG or WIN55212-2 was decreased in CB1RSMKO vessels, suggesting that activation of CB1RSM mediates the vasodilation effect of cannabinoids. Ischemia stroke mouse model was used to further identify the potential function of CB1RSM in pathological conditions, and the results showed that the infarct volume in CB1RSMKO mice is significantly increased compared with the control littermates. These results suggest that vascular CB1R may not play a central role in basal vascular health maintenance but is protective in ischemia states, such as stroke. The protection function may be mediated, at least partly, by the relaxation effect of CB1RSM-dependent activities of endocannabinoids.

3.
Biotechnol Prog ; : e3218, 2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34601810

RESUMO

The Candida Antarctica lipase B (CALB) was embedded in the metal-organic framework, zeolitic imidazolate framework-8 (ZIF-8) and applied in the enzymatic synthesis of L-ascorbic acid palmitate (ASP) for the first time. The obtained CALB@ZIF-8 achieved the enzyme loading of 80 mg/g with 11.3 U/g (dry weight) unit activity, 59.8% activity recovery and 92.7% immobilization yield. Under the optimal condition, ASP was synthesized with over 75.9% conversion of L-ascorbic acid in a 10-batch reaction. Continuous synthesis of ASP was subsequently performed in a packed bed bioreactor with an outstanding average space-time yield of 58.1 g L-1 h-1 , which was higher than ever reported continuous ASP biosynthesis reactions. This article is protected by copyright. All rights reserved.

4.
Artigo em Inglês | MEDLINE | ID: mdl-34519920

RESUMO

Sucrose isomerase (SIase) is a key enzyme used for the production of isomaltulose from sucrose. In this study, an SIase gene from Erwinia sp. Ejp617 (ErSIase) was heterologously expressed in Escherichia coli BL21(DE3), and the recombinant ErSIase was served as biocatalyst combined with the graphene oxide (GO) as carrier for ErSIase immobilization. The Fourier transform infrared spectroscopy, transmission electron microscope, and confocal laser microscopy analyses showed that ErSIase was successfully immobilized on the surface of GO to form ErSIase-GO. The loading capacity of ErSIase on GO reached up to 460 mg/g with a specific activity of 727.04 U/mg protein when the optimal immobilization time of 12 h and the ErSIase/GO ratio of 7.4:4 (w/w) were applied. A high conversion rate of 95.3% was reached from sucrose to isomaltulose using ErSIase-GO as biocatalyst with 600 g/L sucrose as substrate, after 180 min at 40 °C and pH 6.0. Moreover, stabilities of the immobilized ErSIase-GO in the aspects of thermal, pH, and storage were improved, and its activity after 10 batches still remained around 80% under the optimal conditions. The Km value of ErSIase-GO was 29.32 mM, and the kcat/Km was increased to 27.34 s-1 mM-1 when 0.1% (w/v) detergent NP40 was added. These results indicated that the ErSIase was well immobilized onto GO, and the ErSIase-GO is a promising biocatalyst with high operational stability and catalytic activity for industrial production of isomaltulose.

5.
J Agric Food Chem ; 69(40): 12002-12011, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34590865

RESUMO

Xylitol is a widely used natural sweetener for the reduction of excessive sugar consumption. However, concerns of xylitol consumption existed as it is a highly permeable substance in the colon that could cause diarrhea and other adverse symptoms. To assess the relationship between xylitol dosage and diarrhea, especially the influences of diarrhea on physiological characteristics, the immune system, and gut microbiota in rats, the control, low-dose (L), medium-dose (M), and high-dose (H) groups were fed with 0, 1, 3, and 10% of xylitol, respectively, correspondingly for 15 days, followed by a 7-day recovery. Only medium- and high-dose xylitol would cause diarrhea in rats. Quantitative imaging of colonic tissue and the expression levels of proinflammatory factors revealed a higher degree of immune responses in the rats from H groups but statistically stable in M groups, despite that light diarrhea was observed. A shift of the gut microbiota composition was observed in the rats from H groups, including significant decreases of genera Ruminococcaceae and Prevotella and a notable increase and colonization of Bacteroides, accompanied with changes of short-chain fatty acid production. Tolerance and adaptation to xylitol consumption were observed in a dose-dependent manner. Our findings demonstrate that diarrhea caused by the high dosage of xylitol can exert distinctive changes on gut microbiota and lay the foundation to explore the mechanism underlying the shift in gut microbiota composition.


Assuntos
Microbioma Gastrointestinal , Animais , Diarreia , Ácidos Graxos Voláteis , Intestinos , Ratos , Xilitol
6.
J Genet Genomics ; 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34555548

RESUMO

Plant glandular trichomes are epidermal secretory structures that are important for plant resistance to pests. Although several regulatory genes have been characterized in trichome development, the molecular mechanisms conferring glandular trichome morphogenesis are unclear. We observed the differences in trichomes in cultivated tomato cv. 'Moneymaker' (MM) and the wild species Solanum pimpinellifolium PI365967 (PP), and used a recombinant inbred line (RIL) population to identify the genes that control trichome development in tomato. We found that the genomic variations in two genes, H and SH, contribute to the trichome differences between MM and PP. H and SH encode two paralogous C2H2 zinc-finger proteins that function redundantly in regulating trichome formation. Loss-of-function h/sh double mutants exhibited a significantly decreased number of Type I trichomes and complete loss of long stalk trichomes. Molecular and genetic analyses further indicate that H and SH act upstream of ZFP5. Overexpression of ZFP5 partially restored the trichome defects in NIL-hPPshPP. Moreover, H and SH expression is induced by high temperatures, and their mutations inhibit the elongation of trichomes that reduce the plant repellent to whiteflies. Our findings confirm that H and SH are two vital transcription factors controlling initiation and elongation of Type I and III multicellular trichomes in tomato.

7.
J Am Chem Soc ; 143(37): 15440-15452, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34478267

RESUMO

Neutral ketene is a crucial intermediate during zeolite carbonylation reactions. In this work, the roles of ketene and its derivates (viz., acylium ion and surface acetyl) associated with direct C-C bond coupling during the carbonylation reaction have been theoretically investigated under realistic reaction conditions and further validated by synchrotron radiation X-ray diffraction (SR-XRD) and Fourier transformed infrared (FT-IR) studies. It has been demonstrated that the zeolite confinement effect has significant influence on the formation, stability, and further transformation of ketene. Thus, the evolution and the role of reactive and inhibitive intermediates depend strongly on the framework structure and pore architecture of the zeolite catalysts. Inside side pockets of mordenite (MOR), rapid protonation of ketene occurs to form a metastable acylium ion exclusively, which is favorable toward methyl acetate (MA) and acetic acid (AcOH) formation. By contrast, in 12MR channels of MOR, a relatively longer lifetime was observed for ketene, which tends to accelerate deactivation of zeolite due to coke formation by the dimerization of ketene and further dissociation to diene and alkyne. Thus, we resolve, for the first time, a long-standing debate regarding the genuine role of ketene in zeolite catalysis. It is a paradigm to demonstrate the confinement effect on the formation, fate, and catalytic consequence of the active intermediates in zeolite catalysis.

8.
Blood Adv ; 5(18): 3656-3667, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34470047

RESUMO

Proteasome inhibitors, such as bortezomib (BTZ), represent the key elements in chemotherapy regimens for multiple myeloma (MM), whereas acquired chemoresistance and ultimately relapse remain a major obstacle. In the current study, we screened differently expressed cytokines in bortezomib-resistant MM cells and found that Dickkopf-1 (DKK1) level was remarkably augmented, whereas CD138 level was significantly suppressed. DKK1 in vitro specifically enhanced the resistance of myeloma cells to bortezomib treatment, and excessive DKK1 drove CD138 downregulation via inhibition of canonical Wnt signaling. Notably, DKK1 mainly induced drug resistance in MM cells via the receptor of CKAP4. Mechanistically, CKAP4 transduced DKK1 signal and evoked NF-κB pathway through recruiting and preventing cullin associated and neddylation dissociated 1 from hampering the assembly of E3 ligase-mediated ubiquitination of IκBα. In addition, we found that interleukin-6 (IL-6) stimulated CKAP4 expression to generate drug resistance, and disturbance of DKK1-CKAP4 axis improved sensitivity to BTZ treatment of MM and attenuated bone destruction in a mouse model. Collectively, our study revealed the previously unidentified role of DKK1 in myeloma drug resistance via Wnt signaling dependent and independent manners, and clarified the importance of antagonism of DKK1-IL-6 loop in bone marrow microenvironment.

9.
Eur J Med Res ; 26(1): 106, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34526101

RESUMO

BACKGROUND: Combined spinal epidural anesthesia (CSEA) is commonly performed in cesarean deliveries. However, it is difficult to perform in obese parturients because of positioning challenges. The aim of this study was to compare the effect of different approaches to CSEA under the guidance of ultrasound. METHODS: One hundred obese patients (BMI ≥ 30 kg/m2) who underwent elective cesarean section were randomly enrolled. Patients were assigned to a median approach group and a paramedian approach group randomly. Clinical characteristics were compared between groups. First-attempt success rate, the median positioning time and total operation time, ultrasonic predicted anesthesia puncture depth, actual puncture depth, anesthesia adverse reactions, complications after anesthesia, and patients' satisfaction with the epidural puncture were recorded. RESULTS: The first-attempt success rate was significantly different between the two groups [92% (46/50) vs. 76% (38/50), P = 0.029]. The median positioning time and total operation time in the paramedian approach group were higher than those in the median approach group (227.7 s vs. 201.6 s, P = 0.037; 251.3 s vs. 247.4 s, P = 0.145). The incidence of postanesthesia complications in the paramedian approach group was significantly lower than that in the median approach group (2% vs. 12%, P = 0.026), and patient satisfaction was higher in the paramedian approach group than in the median approach group (P = 0.032). CONCLUSION: The ultrasound-guided paramedian approach for CSEA is time-consuming, but it can effectively improve the success rate of the first puncture, reduce the incidence of anesthesia-related adverse reactions, and improve patient satisfaction. TRIAL REGISTRATION: This study was registered with the Chinese Clinical Trial Registry (ChiCTR1900024722) on July 24, 2019.

10.
Rapid Commun Mass Spectrom ; : e9203, 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34549468

RESUMO

RATIONALE: The interactions between proteins and ligands are involved in many biological processes and early stage of drug development. Native electrospray ionization mass spectrometry has played an important role in characterization of protein-ligand interactions. Herein, native ESI-MS combined with molecular docking was used for the characterization of ginsenoside-myoglobin (Mb) interactions. METHODS: The binding of ginsenosides (Rb3 , Rc, Rd, Re) to Mb was determined by native ESI-MS. The titration experiments were performed for the calculation of the dissociation constants (Kd ) of the complexes. Molecular docking was used to simulate the binding of ginsenosides with Mb by AutoDock. RESULTS: The ginsenoside-Mb complex with stoichiometric ratio 1:1 was observed by native ESI-MS. The Kd values determined by the direct calculation were matched with those by the curve fitting. However, the relative standard deviations (RSDs) obtained by the direct calculation were bigger than those by the curve fitting. By the molecular docking, it was inferred that hydrophobic interaction, hydrogen bond and Van der Waals forces were participated in the binding of ginsenosides to protein. CONCLUSIONS: The ginsenoside-Mb interactions can be characterized by electrospray ionization mass spectrometry combined with molecular docking. This approach can be helpful to investigate the interactions between natural drugs and protein in various diseases.

11.
J Ethnopharmacol ; 283: 114675, 2021 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-34571078

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Ischemic stroke is the most common type of stroke, with high mortality, disability and recurrence rate, which brings a heavy burden to individuals, families and the medical system. Therefore, the intervention and treatment of ischemic stroke are of great significance. Chinese herbal medicine is widely used in treating stroke, for example, Dengzhan shengmai (DZSM) capsule. The current systematic review aims to comprehensively evaluate the efficacy and safety of the DZSM capsule in treating ischemic stroke. MATERIALS AND METHODS: Eligible randomized controlled trials (RCTs) were included to evaluate the efficacy and safety of Chinese herbal medicine DZSM capsule in treating ischemic stroke. Eight electronic databases were searched up to January 27, 2021. The risk ratio (RR), standardized mean difference (SMD), or weighted mean difference (WMD) with 95% confidence interval (CI) were used to assess DZSM capsule treatment outcomes. RESULTS: A total of 28 RCTs involving 6683 participants were included in the systematic review and meta-analysis. Compared with conventional therapy group, DZSM capsule plus conventional therapy improved Barthel Index scores (WMD: 8.97, 95%CI: 5.88-12.05) and reduced modified Rankin Scale (WMD: -0.75, 95%CI: -1.02∼ -0.48), reduced neurological functional deficit scores (WMD: -2.81, 95%CI: -4.17∼ -1.44), recurrence rate (RR: 0.57, 95%CI: 0.44-0.73) and mortality (RR: 0.54, 95%CI: 0.31-0.95), improved clinical effect (RR: 1.18, 95%CI: 1.12-1.24) and quality of life (WMD: 21.67, 95%CI: 6.74-36.61), exhibited a beneficial effect on hemorheology such as elevated levels of APTT (SMD: 1.17, 95%CI: 0.87-1.47) and INR (SMD: 1.12, 95%CI: 0.82-1.42), and on lipid metabolism such as levels of TC (SMD: -0.62, 95%CI: -1.04 âˆ¼ -0.20), TG (SMD: -0.72, 95%CI: -1.18∼ -0.26), LDL (SMD: -1.14, 95%CI: -1.57∼ -0.71) and HDL (SMD: 0.93, 95%CI: 0.36-1.50). No trials reported severe adverse events. CONCLUSION: DZSM capsule appears to be safe and effective in clinical applications for ischemic stroke. Based on conventional therapy, adding the DZSM capsule could reduce the mortality, recurrence rate, and neurological functional deficit scores, improve clinical effect and quality of life. In addition, compared with conventional therapy, the addition of the DZSM capsule played a beneficial role in hemorheology and lipid metabolism, which may attribute to the potential mechanism.

12.
J Pharm Sci ; 2021 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-34582900

RESUMO

Vacuum freeze-drying is a promising technology widely used in pharmaceuticals. Preparing products with prebuilt porosity has attracted considerable attention due to its potential in shortening process duration. However, the design space for the primary drying of initially unsaturated products remains unclear. A novel index, average power, was proposed in this paper to represents the collapse risk. And a multiphase model was employed in this paper to build the design space for the products with initial voids. The simulation results show that both the drying time and average power show higher sensitivity to the temperature variation than pressure. In addition, the initial saturation has significant impacts on the design space, with small initial saturation resulting in vast design space and vice versa, which implies that small initial saturation is more beneficial for the actual production. This paper would be helpful for the development of freeze-drying.

13.
Carcinogenesis ; 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34546340

RESUMO

Bortezomib-based chemotherapy represents the most prevalent regimens for multiple myeloma (MM), whereas acquired drug resistance remains a major obstacle. Myeloma cells often produce excessive amount of dickkopf-1 (DKK1), giving rise to myeloma bone disease (MBD). However, it remains obscure about the effects and mechanisms of DKK1 in the progression and bortezomib responsiveness of MM cells. In the current study, we found WWP2, an E3 ubiquitin-protein ligase, was downregulated in the bortezomib-resistant cells along with high expression of DKK1. Further investigation revealed that WWP2 was a direct target of Wnt/ß-catenin signaling pathway, and DKK1 suppressed the expression of WWP2 via canonical Wnt signaling. We further identified that WWP2 mediated the ubiquitination and degradation of GLI2, a main transcriptional factor of the hedgehog (Hh) pathway. Therefore, DKK1-induced WWP2 downregulation improved GLI2 stability and activation of Hh signaling pathway, contributing to the resistance to bortezomib of MM cells. Clinical data also validated that WWP2 expression was associated with the treatment response and clinic outcomes of MM patients. WWP2 overexpression restricted MM progression and enhanced cell sensitivity to bortezomib treatment in vitro and in vivo. Taken together, our findings demonstrate that DKK1 facilitates the generation of bortezomib resistance in MM via downregulating WWP2 and activating Hh pathway. Thus, the manipulation of DKK1-WWP2-GLI2 axis might sensitize myeloma cells to proteasome inhibitors.

14.
Int J Biol Macromol ; 187: 850-857, 2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34339787

RESUMO

Echinocandin B deacylase (ECBD) from Actinoplanes utahensis can be applied to produce echinocandin B nucleus (ECBN), an essential intermediate of the echinocandins antifungal drugs such as anidulafungin. To date, the expression of ECBD has been limited to Streptomyces. To achieve the active expression of ECBD in Escherichia coli (E. coli), we constructed a plasmid carrying two subunits of ECBD for T7 RNA polymerase driven transcription of dicistron messenger after codon optimization. Subsequently, the introduction of peptide tags in the recombinant ECBD was adopted to reduce the formation of inclusion bodies and enhance the ECBD solubility. The peptide tags with the opposite electrostatic charge, hexa-lysine (6K) and GEGEG (GE), exhibited the best positive effect, which was verified by activity assay and structural simulation. After that, optimization of culture conditions and characterization of ECBD were conducted, the optimal pH and temperature were 7.0 and 60 °C. It is the first report concerning the functional expression of ECBD in the host E. coli. Our results reported here can provide a reference for the high-level expression of other deacylases with respect to a possible industrial application.

15.
J Sep Sci ; 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34406706

RESUMO

Traditional Chinese medicine believes that qi deficiency is important pathogenesis and syndrome of liver cancer and thus is crucial in related research. However, the effect of qi deficiency on the occurrence and development of liver cancer is still unclear. This study aimed to establish a liver cancer model of qi deficiency through the swimming exhaustion and xenograft of human hepatoma HepG2 cells. The effects of qi deficiency on the occurrence and development of liver cancer were investigated by analyzing tumor development, blood routine, histopathology, and serum metabolomics. Results showed that qi deficiency greatly affected the physiology and tumor growth of xenograft mice. Eight potential biomarkers were identified by metabolomics based on ultra-high performance liquid chromatography and tandem quadrupole time-of-flight mass spectrometry. Their main pathways were arachidonic acid metabolism, phenylalanine metabolism, purine metabolism, glycerolipid metabolism, steroid biosynthesis, sphingomyelin metabolism, and fatty acid metabolism pathway. Finally, the effects of qi deficiency on the occurrence and development of liver cancer were comprehensively analyzed, and the mechanism of this process was preliminarily clarified.

16.
Artigo em Inglês | MEDLINE | ID: mdl-34364297

RESUMO

Qi-deficiency also called energy deficiency, which approximates to the term of sub-health in contemporary medical theory. Diabetes is similar to the symptoms of "xiaoke" in traditional Chinese medicine (TCM) which is linked with Qi-deficiency. However, the mechanism of Qi-deficiency on type 2 diabetes (T2D) has not been completely elucidated. In this study, a model on Qi-deficiency T2D rat was established by using diet with high fat and high sugar and small-dose STZ induction combined with exhaustive swimming, and the model was evaluated by pathological section, hematological index and serum biochemical parameters. Applying urine metabolomics based on ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry to explore the underlying molecular mechanism of Qi-deficiency on T2D and 32 urinary metabolites were identified as prospective biomarkers for Qi-deficiency T2D rats. Metabolic pathway analysis indicated that synthesis and degradation of ketone bodies, starch and sucrose metabolism, phenylalanine metabolism, arachidonic acid metabolism, butanoate metabolism and TCA cycle, etc., were closely related to potential mechanisms of Qi-deficiency on T2D. The metabolomics results can provide reliable data support for complex TCM syndrome diagnosis.

17.
J Nanobiotechnology ; 19(1): 252, 2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34425841

RESUMO

BACKGROUND: The niche of tissue development in vivo involves the growth matrix, biophysical cues and cell-cell interactions. Although natural extracellular matrixes may provide good supporting for seeding cells in vitro, it is evitable to destroy biophysical cues during decellularization. Reconstructing the bioactivities of extracellular matrix-based scaffolds is essential for their usage in tissue repair. RESULTS: In the study, a hybrid hydrogel was developed by incorporating single-wall carbon nanotubes (SWCNTs) into heart-derived extracellular matrixes. Interestingly, insoluble SWCNTs were well dispersed in hybrid hydrogel solution via the interaction with extracellular matrix proteins. Importantly, an augmented integrin-dependent niche was reconstructed in the hybrid hydrogel, which could work like biophysical cues to activate integrin-related pathway of seeding cells. As supporting scaffolds in vitro, the hybrid hydrogels were observed to significantly promote seeding cell adhesion, differentiation, as well as structural and functional development towards mature cardiac tissues. As injectable carrier scaffolds in vivo, the hybrid hydrogels were then used to delivery stem cells for myocardial repair in rats. Similarly, significantly enhanced cardiac differentiation and maturation(12.5 ± 2.3% VS 32.8 ± 5%) of stem cells were detected in vivo, resulting in improved myocardial regeneration and repair. CONCLUSIONS: The study represented a simple and powerful approach for exploring bioactive scaffold to promote stem cell-based tissue repair.

18.
J Biol Chem ; 297(3): 101036, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34343566

RESUMO

Proteins containing breast cancer type 1 (BRCA1) C-terminal domains play crucial roles in response to and repair of DNA damage. Epithelial cell transforming factor (epithelial cell transforming sequence 2 [ECT2]) is a member of the BRCA1 C-terminal protein family, but it is not known if ECT2 directly contributes to DNA repair. In this study, we report that ECT2 is recruited to DNA lesions in a poly (ADP-ribose) polymerase 1-dependent manner. Using co-immunoprecipitation analysis, we showed that ECT2 physically associates with KU70-KU80 and BRCA1, proteins involved in nonhomologous end joining and homologous recombination, respectively. ECT2 deficiency impairs the recruitment of KU70 and BRCA1 to DNA damage sites, resulting in defective DNA double-strand break repair, an accumulation of damaged DNA, and hypersensitivity of cells to genotoxic insults. Interestingly, we demonstrated that ECT2 promotes DNA repair and genome integrity largely independently of its canonical guanine nucleotide exchange activity. Together, these results suggest that ECT2 is directly involved in DNA double-strand break repair and is an important genome caretaker.

19.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120272, 2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34428636

RESUMO

Hydrazine, as a toxic substance, seriously endangers human health and the environment. Based on the excellent luminescent properties and low biological toxicity of pyrene derivatives, combing with chalcone derivatives easily attacked by nucleophilic group, a pyrene derivative PCA decorated by acryloyl terminal group as fluorescent probe for hydrazine was developed. The compound shows fluorescent peak red shift and intensity enhancement with increasing solvent polarity from hexane (459 nm) to methanol (561 nm). Based on strong fluorescence emission in methanol, methanol-HEPES mixed solution was used as the solvent in the spectral recognition experiments. The probe exhibits fluorescent change from yellow fluorescence (576 nm) to blue fluorescence (393 nm) with 800-fold ratiometric fluorescence enhancement (I393nm/I576nm) after the reaction with hydrazine. The probe can recognize hydrazine in fast response rate with kinetic constant calculated being 2.7 × 10-3 s-1 and 15 min as response time. The probe also can monitor hydrazine in real water samples and various soils.

20.
Talanta ; 234: 122690, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364488

RESUMO

Epitope imprinting has proved to be an effective way for fabricating artificial receptors for protein recognition. Surface imprinting over sacrificial supports is particularly favorable for generating high-quality epitope-imprinted cavities, but obtaining nanomaterials by this way is still a challenge. Herein, we propose a method for the synthesis of oriented surface epitope-imprinted open-mouthed polymer nanocapsules (OM-MIP NCs) by sacrificing asymmetric template-modified Janus nanocores. Amine/aldehyde functionalized SiO2 Janus nanoparticles were prepared via the molten-wax-in-water Pickering emulsion approach, an easy scale-up technique. Epitope templates and vinyl groups were coupled to the aldehyde-bearing major side, whereas polyethylene glycol (PEG) chains were grafted to the amine-modified side. Incomplete imprinted shells were then generated principally on the non-PEGylated side via aqueous precipitation polymerization, hence affording OM-MIP NCs after etching the SiO2 nanocores. With a C-terminus nonapeptide of bovine serum albumin (BSA) chosen as a model epitope and polymerizable carbon dots added to the pre-polymerization solution, fluorescent OM-MIP NCs were synthesized for sensing of BSA. Such NCs reached maximal fluorescent response within 15 min, greatly faster than the closed imprinted NCs within 130 min, proving good accessibility of their inner-surface imprinted cavities thanks to the open mouths. Furthermore, they showed excellent target protein detection performance, with an imprinting factor of 7.8, a limit of detection of 43.8 nM and a linear range of 0.2-6 µM. The recoveries in bovine serum samples at four spiking levels ranged from 99.2 to 107.2%, with relative standard deviations of 1.2-5.9%.


Assuntos
Impressão Molecular , Nanocápsulas , Animais , Bovinos , Epitopos , Polímeros , Soroalbumina Bovina , Dióxido de Silício
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