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1.
Methods Mol Biol ; 2050: 175-179, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31468492

RESUMO

Electroporation refers to the application of high strength electric pulse to create transient pores in the membrane, thereby enabling the passage of hydrophilic molecules into the cells. Based on the properties of cell and cell wall, the electroporation parameters vary among the algal species. Here, we demonstrated the optimized protocol for successful introduction of recombinant DNA (~5000 bp) into Nannochloropsis oceanica. The linearized recombinant plasmid that harbors eGFP and Bh-sle as the reporter and marker gene, respectively, was electroporated into the electrocompetent N. oceanica cells at voltage of 2200 V, 50 µF, resistance at 600 Ω using electroporator, and the transformed cells were then screened by molecular analysis. The report exemplifies a straightforward and reliable electroporation strategy for generating transgenic N. oceanica cells.

2.
Rev Sci Instrum ; 90(8): 083501, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31472635

RESUMO

Thomson scattering (TS) is a powerful diagnostics for understanding the plasma conditions in high energy density experiments. With the aid of Monte Carlo simulation and statistical analysis, we demonstrated unreported high precisions of ne, Te, Ti, etc., via fitting the multiple-wavenumber spectra of ion-acoustic featured TS simultaneously. For instance, utilizing this method in the current typical conditions on SG-180kJ laser facility, the precisions of ne, Te would be better than 8% and 0.5%, respectively. We presented the fitting precisions at different cases and the chi-square trends of the single- and dual-branch TS. This diagnostic technique is found to be applicable within a wide range of plasma parameters and wavenumbers, which is practical to prompt much more precise plasma diagnostics in experiments.

3.
Org Lett ; 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31479277

RESUMO

We report the first catalytic, enantioselective reductive bis-functionalization of common amides, which provides a facile access to a variety of 2,2-disubstituted 3-iminoindolines in good yields and with excellent enantioselectivities. The reaction conditions are quite mild and can be run on a gram scale. In this one-pot reaction, three C-C bonds, one ring, and one nitrogen-containing tetrasubstituted carbon stereocenter are created in a catalytic enantioselective manner.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31464027

RESUMO

Transition metal-catalyzed C-H phosphorylation remains an unsolved challenge. Reported methods are generally limited in scope and require stoichiometric silver salts as oxidants. Herein we report an electrochemically driven Rh(III)-catalyzed aryl C-H phosphorylation reaction, which proceeds through H2 evolution obviating the need for stoichiometric metal oxidants. The method is compatible with a variety of aryl C-H and P-H coupling partners and particularly useful for synthesizing triarylphosphine oxides from diarylphosphine oxides, which are often difficult coupling partners for transition metal-catalyzed C-H phosphorylation reactions. Experimental results suggest that the mechanism responsible for the C-P bond formation involves an oxidation-induced reductive elimination process.

5.
Biotechnol J ; 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31464064

RESUMO

Microalgae have long been considered as potential biological feedstock for the production of wide array of bioproducts, such as biofuel feedstock because of their lipid accumulating capability. However, lipid productivity of microalgae is still far below commercial viability. Here we identified a glucose-6-phosphate dehydrogenase from the oleaginous microalga Nannochloropsis oceanica and heterologously expressed it in the green microalga Chlorella pyrenoidosa to characterize its function in the pentose phosphate pathway. We found that the G6PD enzyme activity towards NADPH production was increased by 2.19-fold in engineered microalgal strains. Lipidomic analysis revealed an up to 3.09-fold increase of neutral lipid content in the engineered strains, and lipid yield was gradually increased throughout the cultivation phase and saturated at the stationary phase. Moreover, cellular physiological characteristics including photosynthesis and growth rate were not impaired. Collectively, these results revealed the pivotal role of glucose-6-phosphate dehydrogenase from N. oceanica in NADPH supply, demonstrating that provision of reducing power is crucial for microalgal lipogenesis and could be a potential target for metabolic engineering. This article is protected by copyright. All rights reserved.

6.
Cell Death Dis ; 10(9): 629, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31427569

RESUMO

There is growing evidence that the long non-coding RNAs(lncRNAs) play an important role in the biological behaviors of glioblastoma cells. In this study, we elucidated the function and possible effect and molecular mechanisms of lncRNA-Linc-00313 on the biological behaviors of glioblastoma cells as well as UPF1 function as a RNA-binding protein to enhance its stability. Here, we used qRT-PCR and western blot to measure the expression, cell Transfection to disrupt the expression of genes, cell viability analysis, quantization of apoptosis, cell migration, and invasion assays, Reporter vectors construction and luciferase assays to investigate the malignant biological behaviors of cells, human lncRNA microarrays, RNA-Immunoprecipitation, dual-luciferase gene reporter assay, half-life assay and chromatin immunoprecipitation to verify the binding sites, tumor xenograft implantation for in vivo experiment, SPSS 18.0 statistical software for data statistics. UPF1 and Linc-00313 were both upregulated in glioma tissues and cells. Knockdown of UPF1 or Linc-00313 significantly inhibited malignant biological behaviors of glioma cells by regulating miR-342-3p and miR-485-5p, which are downregulated and functioned as tumor suppressors in glioma. Furthermore, Linc-00313 could acted as a competing endogenous RNA(ceRNA) to regulate the expression of Zic4 by binding to miR-342-3p and miR-485-5p. Interestingly, Zic4 could bind to the promoters of UPF1 and Linc-00313 respectively and upregulate the expression of them. These results indicated that a positive-feedback loop was formed in the regulation of the biological behaviors of glioma cells. The study is the first to prove that the UPF1-Linc-00313-miR-342-3p/miR-485-5p-Zic4-SHCBP1 pathway forms a positive-feedback loop and regulates the biological behaviors of U87 and U251 cells, which might provide a new therapeutic target for glioma.

7.
Cell Death Dis ; 10(9): 632, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31434870

RESUMO

Following the publication of this article, the authors realized there was an error in Figure 6H in which two versions of the figure appear.This does not impact the conclusions of the article.

8.
MAbs ; : 1-13, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31379298

RESUMO

Although process intensification by continuous operation has been successfully applied in the chemical industry, the biopharmaceutical industry primarily uses fed-batch, rather than continuous or perfusion methods, to produce stable monoclonal antibodies (mAbs) from Chinese hamster ovary (CHO) cells. Conventional fed-batch bioreactors may start with an inoculation viable cell density (VCD) of ~0.5 × 106 cells/mL. Increasing the inoculation VCD in the fed-batch production bioreactor (referred to as N stage bioreactor) to 2-10 × 106 cells/mL by introducing perfusion operation or process intensification at the seed step (N-1 step) prior to the production bioreactor has recently been used because it increases manufacturing output by shortening cell culture production duration. In this study, we report that increasing the inoculation VCD significantly improved the final titer in fed-batch production within the same 14-day duration for 3 mAbs produced by 3 CHO GS cell lines. We also report that other non-perfusion methods at the N-1 step using either fed batch or batch mode with enriched culture medium can similarly achieve high N-1 final VCD of 22-34 × 106 cells/mL. These non-perfusion N-1 seeds supported inoculation of subsequent production fed-batch production bioreactors at increased inoculation VCD of 3-6 × 106 cells/mL, where these achieved titer and product quality attributes comparable to those inoculated using the perfusion N-1 seeds demonstrated in both 5-L bioreactors, as well as scaled up to 500-L and 1000-L N-stage bioreactors. To operate the N-1 step using batch mode, enrichment of the basal medium was critical at both the N-1 and subsequent intensified fed-batch production steps. The non-perfusion N-1 methodologies reported here are much simpler alternatives in operation for process development, process characterization, and large-scale commercial manufacturing compared to perfusion N-1 seeds that require perfusion equipment, as well as preparation and storage vessels to accommodate large volumes of perfusion media. Although only 3 stable mAbs produced by CHO cell cultures are used in this study, the basic principles of the non-perfusion N-1 seed strategies for shortening seed train and production culture duration or improving titer should be applicable to other protein production by different mammalian cells and other hosts at any scale biologics facilities.

9.
Sci Rep ; 9(1): 11738, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31409846

RESUMO

Considerable attention has been drawn to the lead halide perovskites (LHPs) because of their outstanding optoelectronic characteristics. LHP nanosheets (NSs) grown from single crystalline lead halide possess advantages in device applications as they provide the possibility for control over morphology, composition, and crystallinity. Here, free-standing lead bromide (PbBr2) single-crystalline NSs with sizes up to one centimeter are synthesized from solution. These NSs can be converted to LHP while maintaining the NS morphology. We demonstrate that these perovskite NSs can be processed directly for fabrication of photodetector and laser arrays on a large scale. This strategy will allow high-yield synthesis of large-size perovskite NSs for functional devices in an integrated photonics platform.

10.
Sci Rep ; 9(1): 11807, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31413276

RESUMO

Radioactive particles were released into the environment during the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Many studies have been conducted to elucidate the chemical composition of released radioactive particles in order to understand their formation process. However, whether radioactive particles contain nuclear fuel radionuclides remains to be investigated. Here, we report the first determination of Pu isotopes in radioactive particles. To determine the Pu isotopes (239Pu, 240Pu and 241Pu) in radioactive particles derived from the FDNPP accident which were free from the influence of global fallout, radiochemical analysis and inductively coupled plasma-mass spectrometry measurements were conducted. Radioactive particles derived from unit 1 and unit 2 or 3 were analyzed. For the radioactive particles derived from unit 1, activities of 239+240Pu and 241Pu were (1.70-7.06) × 10-5 Bq and (4.10-8.10) × 10-3 Bq, respectively and atom ratios of 240Pu/239Pu and 241Pu/239Pu were 0.330-0.415 and 0.162-0.178, respectively. These ratios were consistent with the simulation results from ORIGEN code and measurements from various environmental samples. In contrast, Pu was not detected in the radioactive particles derived from unit 2 or 3. The difference in Pu contents is clear evidence towards different formation processes of radioactive particles, and detailed formation processes can be investigated from Pu analysis.

11.
MAbs ; : 1-13, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31441367

RESUMO

Significant amounts of soluble product aggregates were observed during low-pH viral inactivation (VI) scale-up for an IgG4 monoclonal antibody (mAb IgG4-N1), while small-scale experiments in the same condition showed negligible aggregation. Poor mixing and product exposure to low pH were identified as the root cause. To gain a mechanistic understanding of the problem, protein aggregation properties were studied by varying critical parameters including pH, hold time and protein concentration. Comprehensive biophysical characterization of product monomers and aggregates was performed using fluorescence-size-exclusion chromatography, differential scanning fluorimetry, fluorescence spectroscopy, and dynamic light scattering. Results showed IgG4-N1 partially unfolds at about pH 3.3 where the product molecules still exist largely as monomers owing to strong inter-molecular repulsions and favorable colloidal stability. In the subsequent neutralization step, however, the conformationally changed monomers are prone to aggregation due to weaker inter-molecular repulsions following the pH transition from 3.3 to 5.5. Surface charge calculations using homology modeling suggested that intra-molecular repulsions, especially between CH2 domains, may contribute to the IgG4-N1 unfolding at ≤ pH 3.3. Computational fluid dynamics (CFD) modeling was employed to simulate the conditions of pH titration to reduce the risk of aggregate formation. The low-pH zones during acid addition were characterized using CFD modeling and correlated to the condition causing severe product aggregation. The CFD tool integrated with the mAb solution properties was used to optimize the VI operating parameters for successful scale-up demonstration. Our research revealed the governing aggregation mechanism for IgG4-N1 under acidic conditions by linking its molecular properties and various process-related parameters to macroscopic aggregation phenomena. This study also provides useful insights into the cause and mitigation of low-pH-induced IgG4 aggregation in downstream VI operation.

12.
Chem Commun (Camb) ; 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31469377

RESUMO

This experimental and theoretical study investigates how dynamic solvation environments in switchable ionic liquids regulate the composition of nanoparticulate green rust. A custom microfluidic device enables in situ X-ray absorption spectroscopy to elucidate characterization of the solvent structure and speciation of reaction intermediates of air-sensitive nanoparticles growing in solution.

13.
J Biomed Mater Res A ; 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31408261

RESUMO

Poly-l-lactic acid (PLLA) is widely used in clinic, for example, as biodegradable coronary artery stents. However, inflammatory responses in endothelial cells associated with PLLA degradation are relatively undefined. We previously reported inflammation in human aortic endothelial cells (HAEC) in vitro and in vivo. Here, we further assessed inflammatory injury, including cell migration, cell function, and inflammatory cytokines expressed in HAEC treated with PLLA and curcumin by CCK-8, wound healing assay, ELISA, and Western blot. Significant inhibition of cell migration, remarkable dysfunction, and inflammatory responses were found in HAEC treated with PLLA degradation extract, and these effects were alleviated by Cur treatment. These findings indicated that cautious evaluation of biodegradable polymers should be performed, and Cur represents a promising anti-inflammatory agent for alleviating endothelial dysfunction and inflammation caused by PLLA degradation. In addition, Cur should be further studied experimentally in in vivo experiments on animal models as a potential therapeutic to reduce thrombosis of biodegradable polymer stents.

14.
Rev Sci Instrum ; 90(7): 075108, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31370450

RESUMO

A portable pulsed magnetic field generator for magnetized laser plasma experiments in low vacuum environments is presented. It is based on a classical high-voltage discharge pulsed power system. A 95 kA peak current was delivered at a 65 kV discharge voltage, which generated a quasiuniform magnetic field of 12T in a Φ8 mm × 8 mm volume. A compact, sealed design was developed to avoid short-circuit breakdowns caused by an ambient low-pressure gas medium. Design improvements were made to the vacuum feedthrough, the transmission line, and the magnetic coil. The system worked well in a low vacuum environment for a laser plasma experiment using a gas target. But at intermediate ambient gas pressure, the ambient gas was ionized around the surface of the coil at first and then the ionized gas diffused inward and outward slowly, which affected the laser plasma image in the coil. Experiments and simulations indicated that the ambient gas was ionized by the induced electric field. We developed analytical models of the induced breakdown of the ambient gas to guide the experimental design of a gas target. The analysis can also be used in the experimental design of a solid target in an intense pulsed magnetic field of hundreds of tesla that the induced breakdown along solid's surface dominates the process.

16.
Artigo em Inglês | MEDLINE | ID: mdl-31378655

RESUMO

INTRODUCTION: Although neoadjuvant chemo-radiotherapy (CRT) achieves low local recurrence rates in locally advanced rectal cancer (LARC), it raises a lot of concerns about long-term anal and sexual functions. We explored the efficacy of preoperative chemotherapy with mFOLFOXIRI (folinic acid, 5-fluorouracil, oxaliplatin, and irinotecan) in patients with LARC. PATIENTS AND METHODS: Patients with LARC evaluated by pelvic magnetic resonance imaging (MRI) were enrolled in this trial. All received 4 to 6 cycles of mFOLFOXIRI. MRI was performed to assess clinical response after chemotherapy. Patients with mesorectal fascia-positive or ycT4a/b after re-evaluation would receive radiation before surgery, whereas responders would have immediate total mesorectal excision (TME). Adjuvant chemotherapy with mFOLFOX6 (folinic acid, 5-fluorouracil, and oxaliplatin) was recommended. The primary endpoint was the proportion of tumor downstaging to ypT0-2N0M0. The secondary endpoints were pathologic complete response rate (pCR), 3-year disease-free survival rate, and safety. RESULTS: Overall, 106 patients were enrolled and received neoadjuvant mFOLFOXIRI chemotherapy. A total of 103 participants underwent TME surgery. Among 103 patients who completed at least 4 cycles of preoperative chemotherapy, 2 received short-term radiation before TME, and 12 underwent long-term CRT after MRI evaluation. The pCR rate was 20.4%, and the tumor downstaging rate was 42.7%. Among patients without preoperative long-term radiotherapy, the pCR rate and tumor downstaging rate were 17.4% and 41.3%, respectively. Among the per-protocol population, the tumor downstaging rate was 48.1%, and the pCR rate was 20.3%. The chemotherapy-related toxicity was well-tolerated. CONCLUSION: Neoadjuvant chemotherapy with mFOLFOXIRI and selective radiation does not seem to compromise outcomes in LARC. It could be a reasonable alternative to CRT in previously untreated patients with LARC.

17.
J Am Chem Soc ; 141(34): 13625-13634, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31329459

RESUMO

Enantioselective catalysis of excited-state photoreactions remains a substantial challenge in synthetic chemistry, and intermolecular photoreactions have proven especially difficult to conduct in a stereocontrolled fashion. Herein, we report a highly enantioselective intermolecular [2 + 2] cycloaddition of 3-alkoxyquinolones catalyzed by a chiral hydrogen-bonding iridium photosensitizer. Enantioselectivities as high as 99% ee were measured in reactions with a range of maleimides and other electron-deficient alkene reaction partners. An array of kinetic, spectroscopic, and computational studies supports a mechanism in which the photocatalyst and quinolone form a hydrogen-bonded complex to control selectivity, yet upon photoexcitation of this complex, energy transfer sensitization of maleimide is preferred. The sensitized maleimide then reacts with the hydrogen-bonded quinolone-photocatalyst complex to afford a highly enantioenriched cycloadduct. This finding contradicts a long-standing tenet of enantioselective photochemistry that held that stereoselective photoreactions require strong preassociation to the sensitized substrate in order to overcome the short lifetimes of electronically excited organic molecules. This system therefore suggests that a broader range of alternate design strategies for asymmetric photocatalysis might be possible.

19.
Arch Biochem Biophys ; 672: 108061, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31356776

RESUMO

Autophagy exerts a dual role in promoting cell death or survival. Recent studies have shown that it may play an important role in lipopolysaccharide (LPS)-induced acute lung injury (ALI). It was also suggested that angiotensin converting enzyme 2 (ACE2) may participate in the regulation of autophagy. The present study aims to investigate the role of autophagy in ALI and the involvement of ACE2. The regulation of the APMK/mTOR pathway was explored to clarify the underlying mechanism. The results showed that autophagy played an important role in ALI induced by LPS, as the autophagy inhibitor 3-methyladenine (3-MA) mitigated the severity of ALI. ACE2 activator resorcinolnaphthalein and inhibitor MLN-4760 significantly affected the histological appearance and wet/dry (W/D) ratio of the lung and altered the ACE2 activity of the lung, tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) levels in bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) levels in lung tissue. Furthermore, LPS, resorcinolnaphthalein and MLN-4760 significantly affected the expression of autophagy proteins Beclin-1, LC3-I and LC3-II. To explore the mechanism of ACE2 on lung autophagy, we measured the phosphorylation of AMPK/mTOR after mice were treated with LPS and resorcinolnaphthalein or MLN-4760. The results revealed that resorcinolnaphthalein and MLN-4760 both significantly altered the phosphorylation of AMPK/mTOR. Finally, we found that AMPK inhibitor (8-bAMP) and mTOR activator (propranolol) both abolished the effects of ACE2 activator (resorcinolnaphthalein) on the expression of lung autophagy proteins Beclin-1, LC3-I and LC3-II. In conclusion, these findings suggest that ACE2 could alleviate the severity of ALI, inflammation and autophagy in lung tissue through the AMPK/mTOR pathway.

20.
J Clin Invest ; 130: 3625-3639, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31355779

RESUMO

Type 1 IFNs (IFN-I) generally protect mammalian hosts from virus infections, but in some cases, IFN-I is pathogenic. Because IFN-I is protective, it is commonly used to treat virus infections for which no specific approved drug or vaccine is available. The Middle East respiratory syndrome-coronavirus (MERS-CoV) is such an infection, yet little is known about the role of IFN-I in this setting. Here, we show that IFN-I signaling is protective during MERS-CoV infection. Blocking IFN-I signaling resulted in delayed virus clearance, enhanced neutrophil infiltration, and impaired MERS-CoV-specific T cell responses. Notably, IFN-I administration within 1 day after infection (before virus titers peak) protected mice from lethal infection, despite a decrease in IFN-stimulated gene (ISG) and inflammatory cytokine gene expression. In contrast, delayed IFN-ß treatment failed to effectively inhibit virus replication, increased infiltration and activation of monocytes, macrophages, and neutrophils in the lungs, and enhanced proinflammatory cytokine expression, resulting in fatal pneumonia in an otherwise sublethal infection. Together, these results suggest that the relative timing of the IFN-I response and maximal virus replication is key in determining outcomes, at least in infected mice. By extension, IFN-αß or combination therapy may need to be used cautiously to treat viral infections in clinical settings.

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