Enhanced Structural and Electrochemical Stability of Self-Similar Rice-Shaped SnO₂ Nanoparticles

A facile one-pot hydrothermal strategy is applied to prepare Co and F codoped SnO₂ (Co–F/SnO₂) nanoparticles, which exhibit a unique rice-shaped self-similar structure. Compared with the pristine and Co-doped counterparts (SnO₂ and Co/SnO₂), the Co–F/SnO₂ electrode demonstrates higher capacity, better cyclability, and rate capability as anode material for lithium ion batteries (LIBs). A high charge capacity of 800 mAh g^–1 can be successfully delivered after 50 cycles at 0.1 C, and a high reversible capacity of 700 mAh g^–1 could be retained after 100 cycles at 5 C. The excellent lithium storage performances of the Co–F/SnO₂ nanoparticles could be attributed to the synergetic effects of the doped Co and F, as well as the unique hierarchical self-similar structure with moderate oxygen defect and inactive pillars, which not only facilitates the fast diffusion of Li ions, but also stabilizes the structure during the electrochemical cycling

Metabolic Engineering of Wheat Provitamin A by Simultaneously Overexpressing <i>CrtB</i> and Silencing Carotenoid Hydroxylase (<i>TaHYD</i>)

Increasing the provitamin A content in staple crops via carotenoid metabolic engineering is one way to address vitamin A deficiency. In this work a combination of methods was applied to specifically increase β-carotene content in wheat by metabolic engineering. Endosperm-specific silencing of the carotenoid hydroxylase gene (<i>TaHYD</i>) increased β-carotene content 10.5-fold to 1.76 μg g^–1 in wheat endosperm. Overexpression of <i>CrtB</i> introduced an additional flux into wheat, accompanied by a β-carotene increase of 14.6-fold to 2.45 μg g^–1. When the “push strategy” (overexpressing <i>CrtB</i>) and “block strategy” (silencing <i>TaHYD</i>) were combined in wheat metabolic engineering, significant levels of β-carotene accumulation were obtained, corresponding to an increase of up to 31-fold to 5.06 μg g^–1. This is the first example of successful metabolic engineering to specifically improve β-carotene content in wheat endosperm through a combination of methods and demonstrates the potential of genetic engineering for specific nutritional enhancement of wheat

Coexpression of the High Molecular Weight Glutenin Subunit 1Ax1 and Puroindoline Improves Dough Mixing Properties in Durum Wheat (<em>Triticum turgidum</em> L. ssp. <em>durum</em>)

<div><p>Wheat end-use quality mainly derives from two interrelated characteristics: the compositions of gluten proteins and grain hardness. The composition of gluten proteins determines dough rheological properties and thus confers the unique viscoelastic property on dough. One group of gluten proteins, high molecular weight glutenin subunits (HMW-GS), plays an important role in dough functional properties. On the other hand, grain hardness, which influences the milling process of flour, is controlled by <em>Puroindoline a</em> (<em>Pina</em>) and <em>Puroindoline b</em> (<em>Pinb</em>) genes. However, little is known about the combined effects of HMW-GS and PINs on dough functional properties. In this study, we crossed a <em>Pina</em>-expressing transgenic line with a <em>1Ax1</em>-expressing line of durum wheat and screened out lines coexpressing <em>1Ax1</em> and <em>Pina</em> or lines expressing either <em>1Ax1</em> or <em>Pina</em>. Dough mixing analysis of these lines demonstrated that expression of 1Ax1 improved both dough strength and over-mixing tolerance, while expression of PINA detrimentally affected the dough resistance to extension. In lines coexpressing <em>1Ax1</em> and <em>Pina</em>, faster hydration of flour during mixing was observed possibly due to the lower water absorption and damaged starch caused by PINA expression. In addition, expression of 1Ax1 appeared to compensate the detrimental effect of PINA on dough resistance to extension. Consequently, coexpression of 1Ax1 and PINA in durum wheat had combined effects on dough mixing behaviors with a better dough strength and resistance to extension than those from lines expressing either <em>1Ax1</em> or <em>Pina</em>. The results in our study suggest that simultaneous modulation of dough strength and grain hardness in durum wheat could significantly improve its breadmaking quality and may not even impair its pastamaking potential. Therefore, coexpression of 1Ax1 and PINA in durum wheat has useful implications for breeding durum wheat with dual functionality (for pasta and bread) and may improve the economic values of durum wheat.</p> </div

Scanning electron microscopy analyses of endosperms from transgenic and control lines.

<p>Seeds from two lines expressing <i>1Ax1</i> and <i>Pina</i> (lines HP-19, HP-245), two lines expressing <i>1Ax1</i> (lines H-182, H-293), two lines expressing <i>Pina</i> (lines P-121, P-149), one null segregant line (lines N-1) and non-transformed control cv. Luna were subjected to scanning electron microscope analysis to reveal the structure differences of endosperm. Scale bar = 10 µm.</p

Characterization of storage proteins in transgenic and control lines.

<p>A. SDS-PAGE of seed protein extracts from transgenic lines, null segregant line and non-transformed control line. Transgenic 1Ax1 is indicated by arrow on the left side of the gel. B. Characterization of storage proteins from the transgenic and control lines. HMW % glutenin and LMW % glutenin means quantities of HMW-GS and LMW-GS, respectively, expressed related to total quantity of the glutenins (and the same for Ax, Bx and By). x/y: ratio of the x- and y- type HMW-GS. HMW/LMW: ratio of the high and low molecular weight glutenin subunits. Glutenin %: quantity of the glutenins expressed related to total proteins extracted by the sequential extraction methods (and the same for Gliadin %) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0050057#pone.0050057-DuPont1" target="_blank">[27]</a>. Glu/Glia: ratio of the glutenins and gliadins. 1Ax1+Pina = transgenic lines coexpressing <i>1Ax1</i> and <i>Pina</i> genes (dark grey); 1Ax1 = transgenic lines expressing only <i>1Ax1</i> (light grey); Pina = transgenic lines expressing only <i>Pina</i> (black). Control = both null segregant and non-transformed control lines (white). Data are given as mean ± SEM. Values within the same characteristics of storage proteins followed by the same letter are not significantly different (<i>P</i><0.05).</p

Kernel characteristics, protein contents and Mixograph parameters of the transgenic and control lines.

<p>Values within the same parameter followed by the same letter are not significantly different at 0.05 probability level.</p><p>Protein contents determined by near-infrared reflectance spectroscopy (NIRS) method were adjusted to a 14% moisture basis.</p

SDS-PAGE and Western blotting analyses of total and starch-bound PINA in transgenic and control lines.

<p>A. SDS-PAGE of TX-114-soluble proteins isolated from flours of transgenic and control lines. B. Western blotting results of total PINA. C. Densitometry quantification of western blotting results of total PINA. D. SDS-PAGE of starch bound puroindolines isolated from flours of transgenic and control lines. E. Western blotting results of starch-bound PINA. F. Densitometry quantification of western blotting results of starch bound PINA. PINA protein is indicated by arrow on both stained SDS-PAGE and Western blots. Data are given as mean ± SEM. *and ** indicates the significant differences with the PINA levels of control variety Chinese Spring at 0.05 or 0.01 probability level, respectively.</p

High-Capacity and Long-Cycle Life Aqueous Rechargeable Lithium-Ion Battery with the FePO₄ Anode

Aqueous lithium-ion batteries are emerging as strong candidates for a great variety of energy storage applications because of their low cost, high-rate capability, and high safety. Exciting progress has been made in the search for anode materials with high capacity, low toxicity, and high conductivity; yet, most of the anode materials, because of their low equilibrium voltages, facilitate hydrogen evolution. Here, we show the application of olivine FePO₄ and amorphous FePO₄·2H₂O as anode materials for aqueous lithium-ion batteries. Their capacities reached 163 and 82 mA h/g at a current rate of 0.2 C, respectively. The full cell with an amorphous FePO₄·2H₂O anode maintained 92% capacity after 500 cycles at a current rate of 0.2 C. The acidic aqueous electrolyte in the full cells prevented cathodic oxygen evolution, while the higher equilibrium voltage of FePO₄ avoided hydrogen evolution as well, making them highly stable. A combination of in situ X-ray diffraction analyses and computational studies revealed that olivine FePO₄ still has the biphase reaction in the aqueous electrolyte and that the intercalation pathways in FePO₄·2H₂O form a 2-D mesh. The low cost, high safety, and outstanding electrochemical performance make the full cells with olivine or amorphous hydrated FePO₄ anodes commercially viable configurations for aqueous lithium-ion batteries

Overexpression of Avenin-Like b Proteins in Bread Wheat (<i>Triticum aestivum</i> L.) Improves Dough Mixing Properties by Their Incorporation into Glutenin Polymers

<div><p>Avenin-like b proteins are a small family of wheat storage proteins, each containing 18 or 19 cysteine residues. The role of these proteins, with high numbers of cysteine residues, in determining the functional properties of wheat flour is unclear. In the present study, two transgenic lines of the bread wheat overexpressing <i>avenin-like b</i> gene were generated to investigate the effects of Avenin-like b proteins on dough mixing properties. Sodium dodecyl sulfate sedimentation (SDSS) test and Mixograph analysis of these lines demonstrated that overexpression of Avenin-like b proteins in both transgenic wheat lines significantly increased SDSS volume and improved dough elasticity, mixing tolerance and resistance to extension. These changes were associated with the increased proportion of polymeric proteins due to the incorporation of overexpressed Avenin-like b proteins into the glutenin polymers. The results of this study were critical to confirm the hypothesis that Avenin-like b proteins could be integrated into glutenin polymers by inter-chain disulphide bonds, which could help understand the mechanism behind strengthening wheat dough strength.</p></div

Combined effects of 1Ax1 and PINA on dough mixing properties.

<p>Eleven mixing parameters were compared by Student’s <i>t</i> test between lines coexpressing 1Ax1and Pina (lines HP-19 and HP-245, represented by dark grey bar), lines expressing only <i>1Ax1</i> (lines H-182 and H-293, represented by light grey bar), lines expressing only <i>Pina</i> (lines P-121 and P-149, represented by black bar) and non-transformed control line (cv. Luna, represented by white bar). Data are given as mean ± SEM. *and ** indicates the significant differences with mixing parameters of non-transformed control Luna at 0.05 or 0.01 probability level, respectively.</p