279 research outputs found
Transition metal oxides for high performance sodium ion battery anodes
Sodium-ion batteries (SIBs) are attracting considerable attention with expectation of replacing lithium-ion batteries (LIBs) in large-scale energy storage systems (ESSs). To explore high performance anode materials for SIBs is highly desired subject to the current anode research mainly limited to carbonaceous materials. In this study, a series of transition metal oxides (TMOs) is successfully demonstrated as anodes for SIBs for the first time. The sodium uptake/extract is confirmed in the way of reversible conversion reaction. The pseudocapacitance-type behavior is also observed in the contribution of sodium capacity. For Fe2O3anode, a reversible capacity of 386 mAh g-1at 100 mA g-1 is achieved over 200 cycles; as high as 233 mAhg-1is sustained even cycling at a large current-density of 5 A g-1
Cloning, over-expression, and characterization of a new carboxypeptidase A gene of Bacillus pumilus ML413 in Bacillus subtilis 168
Carboxypeptidase A (CPAs) are a well-studied group of zinc-containing exopeptidases that facilitate thebreakdown of proteins and peptides during metabolism. Carboxypeptidase A is typically produced in mammalian pancreatic, brain and other tissues. A new gene encoding carboxypeptidase A in the prokaryote Bacillus pumilus was amplified by polymerase chain reaction (PCR), ligated into the shuttle vector pMA5, and cloned in a GRAS bacteria-Bacillus subtilis 168 host. This gene sequence contained a 1621 bp open reading frame that encodes a protein of 540 amino acids. The optimum pH and temperature for enzyme activity were 7.5 and 50°C, respectively. The enzyme was quite stable at neutral pH and maintained about 65% activity following a 24 h incubation at 40°C. The Km of this CPA was 0.1 mM, much higher than in mammalian species. Glycerol, ammonium sulfate, and sodium citrate improved enzyme activity under optimal culture condition. The carboxypeptidase activity in recombinant B. subtilis 168 reached a maximum of 179 U ml-1 in a 5 L fermentator when cultured on improved medium. The over expression of carboxypeptidase A in Bacillus subtilis has commercial applications.Key words: Bacillus pumilus, Bacillus subtilis 168, over-expression, orthogonal arrays, carboxypeptidase A,metallocarboxypeptidase
Over-expression of Mycobacterium neoaurum 3-ketosteroid-\u3941-dehydrogenase in Corynebacterium crenatum for efficient bioconversion of 4-androstene-3,17-dione to androst-1,4-diene-3,17-dione
Background: 3-Ketosteroid-\u3941-dehydrogenase (KSDD), a flavoprotein
enzyme, catalyzes the bioconversion of 4-androstene-3,17-dione (AD) to
androst-1,4-diene-3,17-dione (ADD). To date, there has been no report
about characterization of KSDD from Mycobacterium neoaurum strains,
which were usually employed to produce AD or ADD by fermentation.
Results: In this work, Corynebacterium crenatum was chosen as a new
host for heterologous expression of KSDD from M. neoaurum JC-12 after
codon optimization of the KSDD gene. SDS-PAGE and western blotting
results indicated that the recombinant C. crenatum harboring the
optimized ksdd (ksddII) gene showed significantly improved ability to
express KSDD. The expression level of KSDD was about 1.6-fold increased
C. crenatum after codon optimization. After purification of the
protein, we first characterized KSDD from M. neoaurum JC-12, and the
results showed that the optimum temperature and pH for KSDD activity
were 30\ub0C and pH 7.0, respectively. The Km and Vmax values of
purified KSDD were 8.91 \u3bcM and 6.43 mM/min. In this work, C.
crenatum as a novel whole-cell catalyst was also employed and validated
for bioconversion of AD to ADD. The highest transformation rate of AD
to ADD by recombinant C. crenatum was about 83.87% after 10 h reaction
time, which was more efficient than M. neoaurum JC-12 (only 3.56% at 10
h). Conclusions: In this work, basing on the codon optimization,
overexpression, purification and characterization of KSDD, we
constructed a novel system, the recombinant C. crenatum SYPA 5-5
expressing KSDD, to accumulate ADD from AD efficiently. This work
provided new insights into strengthening sterol catabolism by
overexpressing the key enzyme KSDD, for efficient ADD production
KEAP1 overexpression is correlated with poor prognosis and immune infiltration in liver hepatocellular carcinoma
PurposeLiver hepatocellular carcinoma (LIHC) is the most common type of liver cancer, but there is a lack of effective indicators for its early diagnosis and prognosis, so we explored the role of KEAP1 in LIHC patients in this study.MethodsThe Cancer Genome Atlas (TCGA) dataset was used to investigate the relationship between KEAP1 expression and clinicopathological features and prognosis of LIHC patients. KEAP1 expression related pathways were enriched by Gene Ontology (GO) and gene set enrichment analysis (GSEA). Besides, KEAP1 expression-related immune infiltration was performed by single-sample GSEA (ssGSEA), and function of immune cells was detected by flow cytometry.ResultsIt was found that KEAP1 expression was significantly increased and correlated with overall survival of LIHC patients. A total of 231 differentially expressed genes (DEGs) between LIHC patients with high- and low-KEAP1 expression were found, which associated with various biological pathways. Besides, KEAP1 expression was positively correlated with the infiltration level of T helper cells and Th2 cells but negatively correlated with DCs and cytotoxic cells. Functional analysis revealed that the expression of IL 4 in Th2 cells and CD107a, GrA and GrB in cytotoxic cells was significantly greater in LIHC patients than in HCs. In addition, KEAP1 expression was closely correlated with liver function in LIHC patients.ConclusionHighly expressed KEAP1 was closely related to the diagnosis, prognosis, immune cell infiltration, and liver function of LIHC, which might promote the progression of LIHC through regulating cell development, signal transduction, and abnormal immune response. The current study partially revealed the role of KEAP1 in LIHC and provided a potential biomarker for the diagnosis, prognosis and treatment of LIHC
Cocaine- and amphetamine-regulated transcript promotes the differentiation of mouse bone marrow-derived mesenchymal stem cells into neural cells
<p>Abstract</p> <p>Background</p> <p>Neural tissue has limited potential to self-renew after neurological damage. Cell therapy using BM-MSCs (bone marrow mesenchymal stromal cells) seems like a promising approach for the treatment of neurological diseases. However, the neural differentiation of stem cells influenced by massive factors and interactions is not well studied at present.</p> <p>Results</p> <p>In this work, we isolated and identified MSCs from mouse bone marrow. Co-cultured with CART (0.4 nM) for six days, BM-MSCs were differentiated into neuron-like cells by the observation of optical microscopy. Immunofluorescence demonstrated that the differentiated BM-MSCs expressed neural specific markers including MAP-2, Nestin, NeuN and GFAP. In addition, NeuN positive cells could co-localize with TH or ChAT by double-labled immunofluorescence and Nissl bodies were found in several differentiated cells by Nissl stain. Furthermore, BDNF and NGF were increased by CART using RT-PCR.</p> <p>Conclusion</p> <p>This study demonstrated that CART could promote the differentiation of BM-MSCs into neural cells through increasing neurofactors, including BNDF and NGF. Combined application of CART and BM-MSCs may be a promising cell-based therapy for neurological diseases.</p
Structural phase transitions in ionic conductor Bi 2 O 3 by temperature dependent XPD and XAS
The superionic behavior of cubic δ-phase Bi2O3, a metastable phase at high temperature, is of great interests from both scientific and technological perspectives. With the highest ionic conductivity among all known compounds, the δ-phase Bi2O3 possesses promising applications in solid-oxide fuel cells. Previous investigations pointed out the α to δ- phase transition occurs during the heating process, as supported by the X-ray and Neutron diffraction experiments. Through in situ measurements of the long-range order structure and the local structure by X-ray powder diffraction and X-ray absorption spectroscopy, we investigated the evolution of the structures under different temperatures. Both techniques provided ample evidence that the existence of meta-stable β-phase are crucial for forming the defective fluorite cubic δ phase. Our finding suggested that the phase transition from tetragonal β-phase to δ-phase is an influencing factor for the generation of the oxygen-ion pathways
Down-regulation of Stargazin Inhibits the Enhanced Surface Delivery of α-Amino-3-hydroxy-5-methyl-4-isoxazole Propionate Receptor GluR1 Subunit in Rat Dorsal Horn and Ameliorates Postoperative Pain
Stargazin is the first transmembrane protein known to regulate synaptic targeting of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors. Yet, it is unclear whether regulation of the surface delivery of spinal AMPA receptor subunits by stargazin contributes to postoperative pain development
Expression Profiling and Proteomic Analysis of JIN Chinese Herbal Formula in Lung Carcinoma H460 Xenografts
Many traditional Chinese medicine (TCM) formulae have been used in cancer therapy. The JIN formula is an ancient herbal formula recorded in the classic TCM book Jin Kui Yao Lue (Golden Chamber). The JIN formula significantly delayed the growth of subcutaneous human H460 xenografted tumors in vivo compared with the growth of mock controls. Gene array analysis of signal transduction in cancer showed that the JIN formula acted on multiple targets such as the mitogen-activated protein kinase, hedgehog, and Wnt signaling pathways. The coformula treatment of JIN and diamminedichloroplatinum (DDP) affected the stress/heat shock pathway. Proteomic analysis showed 36 and 84 differentially expressed proteins between the mock and DDP groups and between the mock and JIN groups, respectively. GoMiner analysis revealed that the differentially expressed proteins between the JIN and mock groups were enriched during cellular metabolic processes, and so forth. The ones between the DDP and mock groups were enriched during protein-DNA complex assembly, and so forth. Most downregulated proteins in the JIN group were heat shock proteins (HSPs) such as HSP90AA1 and HSPA1B, which could be used as markers to monitor responses to the JIN formula therapy. The mechanism of action of the JIN formula on HSP proteins warrants further investigation
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