51 research outputs found
Utilizing Phosphating Sludge to Synthesize Lithium Iron Phosphate with a Hybrid Coating of Metal Oxides and Carbon
In
order to utilize the hazardous phosphating sludge, a novel approach
including FeCl<sub>3</sub> solution replacement leaching and MeO (metal
oxides) coprecipitation coating is proposed to prepare LiFePO<sub>4</sub> coated with metal oxides and carbon, where FePO<sub>4</sub> is recycled from phosphating sludge and its valuable impurities
are utilized as coating materials. The FeCl<sub>3</sub> solution replacement
leaching is a process for PO<sub>4</sub><sup>3+</sup> enrichment and
FePO<sub>4</sub> purifying. The metal ions (Zn<sup>2+</sup>, Ca<sup>2+</sup>, Mn<sup>2+</sup>, etc.) of the impurity phosphates can be
leached into the solution, meanwhile their corresponding PO<sub>4</sub><sup>3–</sup> are reprecipitated as FePO<sub>4</sub>, whose
Fe<sup>3+</sup> come from the FeCl<sub>3</sub> leaching solution.
Taking the obtained FePO<sub>4</sub> as the core material, the MeO
can be coprecipitated from the leached solution and coated onto the
FePO<sub>4</sub> particle uniformly under the critical pH and appropriate
concentration. This uniform hybrid coating is helpful to avoid the
asymmetrical conductivity both for electron and lithium ion on the
surface of the LiFePO<sub>4</sub> particle, and hence improve its
electrochemical performance. In result, the phosphating sludge is
utilized in a fine and high atom utilization way, which meets the
requirements of hazardous waste reusing and LiFePO<sub>4</sub> modification
PKA phosphorylates and interacts with SF2/ASF.
<p>A, Recombinant GST-SF2/ASF or GST was incubated with PKA in the presence of [γ-<sup>32</sup>P]ATP at 30°C for 10 min, and the reaction mixture was then separated by SDS-PAGE and visualized with Coommassie blue staining (lower panel) or autoradiograph (upper panel). B, PKA-Cα was pull-down by SF2/ASF. GST-SF2/ASF or GST coupled onto glutathione-Sepharose or glutathione-Sepharose (GSH-beads) was incubated with rat brain extract. After extensively washing, the bound proteins were analyzed by Western blots developed with anti-GST or anti-PKA-Cα. C, PKA-Cα was co-immunoprecipitated by anti-HA. SF2/ASF tagged with HA were expressed in HEK-293FT cells for 48 h. The cell extracts were immunoprecipitated with anti-HA, and the immunoprecipitates were subjected to Western blots developed with anti-HA and anti-PKA-Cα. D, HeLa cells were transfected with pCEP4/SF2/ASF and treated without (Con) or with forskolin (Fors) for 30 min, followed by triple immunofluorescence staining.</p
PKA promotes exclusion of exons 14, 15, and 16 of CaMKIIδ.
<p>A, Forskolin treatment activated PKA. HEK-293T cells were transfected with pCI/CaMKIIδ<sub>E13–E17</sub> for 40 hrs and then treated with 10 µM forskolin for 8 hrs. The cells were subjected to Western blots for detection of PKA activity with anti-phosphorylated CREB at Ser133 and anti-CREB. B, Forskolin treatment promoted the exclusion of exons 14, 15, and 16, resulting in an increase in CaMKIIδC expression. HEK-293T cells were transfected with pCI/CaMKIIδ<sub>E13–E17</sub> for 40 hrs and then treated with 10 µM forskolin for 8 hrs. The splicing products were measured with RT-PCR. Each splicing product was quantitated by densitometry, and the percentage of each splicing form was calculated. C, Overexpression of PKA-Cα increased PKA activity. HEK-293T cells were co-transfected with pCI/CaMKIIδ<sub>E12–E17</sub> and pCI/PKA-Cα for 48 hrs. The PKA activity in the cells was measured by phosphorylation of CREB at Ser133 with Western blots. D, Overexpression of PKA-Cα promoted the exclusion of exons 14, 15, and 16 of CaMKII™. HEK-293T cells were cotransfected with pCI/CaMKIIδ<sub>E13–E17</sub> and pCI/PKA-Cα for 48 hrs. The splicing products were measured with RT-PCR. Each splicing product was quantitated by densitometry, and the percentage of each splicing form was calculated. The Data are presented as mean ± S.D. *<i>p</i><0.05 versus control treatment.</p
<i>ritf1</i> mutant plants are sensitive to salt and oxidative stresses, and overexpression of <i>RITF1</i> increases plant tolerance to salt and oxidative stresses.
<p>(A) Seed germination of wild type and <i>ritf1</i> in response to various NaCl levels. There were 80–150 seeds per genotype per biological replicate. (B) Fresh weight of wild-type and <i>ritf1</i> seedlings under salt stress. Five-d-old seedlings grown on MS medium were transferred to MS medium containing 0 or 100 mM NaCl and allowed to grow for an additional 7 d. (C) Growth responses of wild-type and <i>ritf1</i> seedlings to oxidative stress-inducing reagents H<sub>2</sub>O<sub>2</sub> and methyl viologen (MV). (D) and (E) Fresh weight of seedlings grown on MS medium containing various levels of H<sub>2</sub>O<sub>2</sub> (D) or MV (E) as shown in (C). (F) Salt tolerance of <i>RITF1</i> overexpression plants. Five-d-old seedlings grown on MS medium were transferred to MS medium containing 0 or 100 mM NaCl and allowed to grow for an additional 10 d. (G) and (H) Fresh weight of wild-type and <i>RITF1</i> overexpression plants grown on MS medium containing various levels of H<sub>2</sub>O<sub>2</sub> (G) or MV (H). In (C)–(E), (G), and (H), seeds were sown directly on MS medium supplemented with various levels of H<sub>2</sub>O<sub>2</sub> or MV and allowed to grow for an additional 10 d. Error bars represent the standard deviation (n = 8 in [A], 40 in [B], [D]–[H]). One-way ANOVA (Tukey-Kramer test) was performed, and statistically significant differences are indicated by different lowercase letters (p<0.05). The experiments in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003755#pgen-1003755-g005" target="_blank">Figure 5</a> were repeated at least four times with similar results, and data from one representative experiment are presented.</p
SF2/ASF promotes the exclusion of exons 14, 15, and 16 of CaMKIIδ.
<p>A and B, Overexpression of SF2/ASF promoted the exclusion of exons 14, 15, and 16 of pCI/CaMKIIδ<sub>E12–E17</sub> in COS7 cells. PCI/CAMKIIδ<sub>E12–E17</sub> was co-transfected with pCEP4/SF2/ASF into COS7 cells for 48 hr. The splicing products were measured with RT-PCR (A). Each splicing product was quantitated by densitometry and the percentage of each splicing form was calculated (B). C and D, Overexpression of SF2/ASF promoted the exclusion of exons 14, 15, and 16 of pCI/CaMKIIδ<sub>E13–E17</sub> in HEK-239T. PCI/CAMKIIδ<sub>E12–E17</sub> was co-transfected with pCEP4/SF2/ASF into HEK-293T cells for 48 hr. The splicing products were measured with RT-PCR (C). The each splicing product was quantitated by densitometry and the percentage of each splicing form was calculated (D). The Data are presented as mean ± S.D. *<i>p</i><0.05 versus control treatment.</p
A working model for RSA1 and RITF1 function under salt stress.
<p>The calcium-binding protein RSA1 senses salt-induced changes in nuclear free calcium and interacts with a bHLH transcription factor, RITF1. RITF1 may be phosphorylated by nuclear-localized MAPKs. The RSA1-RITF1 complex controls expression of genes important for detoxification of salt-induced ROS and for Na<sup>+</sup> homeostasis under salt stress. Some RITF1 target genes may play a role in salt tolerance with so far unknown mechanisms. The calcium-binding protein SOS3 senses salt-induced cytosolic calcium increases and interacts with SOS2, a protein kinase. The SOS3-SOS2 protein kinase complex then phosphorylates and thereby activates the plasma membrane-localized Na<sup>+</sup>/H<sup>+</sup> antiporter SOS1.</p
Alternative splicing of CaMKIIδ exons 14, 15, and 16 generates three splicing variants, corresponding to CaMKIIδ isoforms A, B, and C, respectively.
<p>A and B, Schematic diagram of the alternative splicing of exons 14, 15, and 16 of mini -CaMKIIδ-genes, pCI/CaMKIIδ<sub>E12–E17</sub> (A) and pCI/CaMKIIδ<sub>E13–E17</sub> (B). C and D, Three splicing variants was generated from mini-CaMKIIδ gene, pCI/CaMKIIδ<sub>E12–E17</sub> (C) or pCI/CaMKIIδ<sub>E13–E17</sub> (D), after transfection into HEK-293T or COS7 cells, respectively, for 48 hrs. The total RNA was used for measurement of the splicing products with RT-PCR.</p
<i>rsa1-1</i> plants are hypersensitive to NaCl, and RSA1 is involved in Na<sup>+</sup> homeostasis under salt stress.
<p>(A)–(C) Five-d-old wild-type and <i>rsa1-1</i> seedlings grown on MS medium were transferred to MS medium supplemented with different levels of NaCl and allowed to grow for an additional 8 d. Root elongation or shoot fresh weight was measured and is shown as a percentage relative to growth on normal MS medium. (D) Two-week-old wild-type and <i>rsa1-1</i> plants grown in soil were irrigated with 300 mM NaCl for 0 or 14 d. (E) Survival rate of wild-type and <i>rsa1-1</i> plants as shown in (D). (F) Seed germination of wild type and <i>rsa1-1</i> in response to various NaCl levels. There were 80–150 seeds per genotype per biological replicate. Seeds in which the radical had emerged through the seed coat were considered germinated. (G) Na<sup>+</sup> content in soil-grown wild-type and <i>rsa1-1</i> plants. DW, dry weight. (H) K<sup>+</sup> content in soil-grown wild-type and <i>rsa1-1</i> plants. (I) Ratio of Na<sup>+</sup> to K<sup>+</sup> accumulation in soil-grown wild-type and <i>rsa1-1</i> plants. WT, wild type. Error bars indicate the standard deviation (n = 30–40). The experiments in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003755#pgen-1003755-g001" target="_blank">Figure 1</a> were repeated at least five times with similar results, and data from one representative experiment are presented.</p
RSA1 interacts with RITF1.
<p>(A) RSA1 interacts with RITF1 as determined by yeast two-hybrid assays. Yeast strain AH109 co-transformed with RSA1-pDEST32 (bait) and RITF1-pDEST22 (prey) was subjected to x-gal assay. AH109 cells co-transformed with RSA1-pDEST32/pDEST22 (empty vector) or RITF1-pDEST22/pDEST32 (empty vector) were used as negative controls. Yeast cells grown on SD medium-L-W or SD medium-L-W-H+3-AT are shown. 3-AT, 3-amino-1,2,4-triazole. L, W, H, symbols for amino acids leucine, tryptophan, and histidine, respectively. SD, yeast minimal media. (B) Localization of RITF1-GFP in <i>Arabidopsis</i> protoplasts. Bar = 25 µm. (C) RSA1 interacts with RITF1 <i>in vivo</i> as determined by BiFC assays in tobacco leaf epidermal cells. Bars = 25 µm in (a), and 50 µm in (b) and (c). YFP images were detected at an approximate frequency of 4.04% (101 out of 2,501 tobacco leaf epidermal cells analyzed exhibited BiFC events). (D) RSA1 interacts with RITF1 <i>in vivo</i> as determined by Split-LUC assays. (E) RSA1 interacts with RITF1 <i>in vivo</i> as determined by Co-IP assays. (F) <i>RITF1</i> expression under salt stress. The qRT-PCR analysis was carried out with 14-d-old wild-type seedlings grown for 6 h on MS medium containing 0, 100, or 150 mM NaCl. Error bars represent the standard deviation (n = 20 in [D], 4 in [F]). The experiments in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003755#pgen-1003755-g004" target="_blank">Figure 4</a> were performed at least three times with similar results, and data from one representative experiment are presented.</p
PKA activation enhances SF2/ASF-promoted exclusion of exons 14, 15, and 16 of CaMKIIδ.
<p>A, HEK-293FT cells were transfected with pCI/CaMKIIδ<sub>E13–E17</sub> for 40 hrs and then treated with 10 µM forskolin or 20 µM isoproterenol for 8 hrs. The splicing products were measured with RT-PCR. Each splicing product was quantitated by densitometry and the percentage of each splicing form was calculated. The Data are presented as mean ± S.D. *<i>p</i><0.05 versus control treatment. B, Proposed mechanism by which abnormalities of β-adrenergic-PKA-pathway dysregulates the alternative splicing of exons 14, 15, and 16 of CaMKIIδ via SF2/ASF.</p
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