Metabolomics Reveals Distinct Carbon and Nitrogen Metabolic Responses to Magnesium Deficiency in Leaves and Roots of Soybean [Glycine max (Linn.) Merr.]

Magnesium (Mg) deficiency, a widespread yet overlooked problem in agriculture, has been reported to retard plant growth and development, through affecting key metabolic pathways. However, the metabolic responses of plant to Mg deficiency is still not fully understood. Here we report a metabolomic study to evaluate the metabolic responses to Mg deficiency in soybean leaves and roots. Hydroponic grown soybean were exposed to Mg starvation for 4 and 8 days, respectively. Metabolic changes in the first mature trifoliolate leaves and roots were quantified by conducting GC-TOF-MS based metabolomic analysis. Principal component analysis (PCA) showed that Mg deficient plants became distinguishable from controls at 4 days after stress (DAS) at metabolic level, and were clearly discriminated at 8 DAS. Mg deficiency could cause large metabolite alterations on carbon and nitrogen metabolism. At 8 DAS, carbon allocation from shoot to root is decreased by Mg deficiency. Remarkably, most amino acids (such as phenylalanine, asparagine, leucine, isoleucine, glycine, glutamine, and serine) showed pronounced accumulation in the leaves, while most organic acids (including pyruvic acid, citric acid, 2-keto-glutaric acid, succinic acid, fumaric acid, and malic acid) were significantly decreased in the roots. Our study shows that the carbon and nitrogen metabolic responses are distinct in leaves and roots under Mg deficiency

Thermal Characteristics of Multilayer Insulation Materials for Flexible Thin-Film Solar Cell Array of Stratospheric Airship

Flexible thin-film solar cell is an efficient energy system on the surface of stratospheric airship for utilizing the solar energy. In order to ensure the normal operation of airship platform, the thermal control problem between the flexible thin-film solar cell and the airship envelope should be properly resolved. In this paper, a multilayer insulation material (MLI) is developed first, and low temperature environment test is carried out to verify the insulation effect of MLI. Then, a thermal heat transfer model of flexible thin-film solar cell and MLI is proposed, and the equivalent thermal conductivity coefficients of flexible thin-film solar cell and Nomex honeycomb are calculated based on the environment test and the temperature profile of flexible thin-film solar cell versus each layer of MLI. Finally, FLUENT is used for modeling and simulation analysis on the flexible thin-film solar cell and MLI, and the simulation results agree well with the experimental data, which validate the correctness of the proposed heat transfer model of MLI. In some way, our study can provide helpful support for further engineering applications of flexible thin-film solar cell

Efficient production of sTNFRII-gAD fusion protein in large quantity by use of the modified CHO-S cell expression system.

TNFα is one of the initial and important mediators to activate downstream signaling pathways by binding to trimerized TNFα receptors (TNFR), and thus is an ideal drug target for cancer therapy. Taking advantage of intrinsic homotimerization of the globular domain of adiponectin (gAD), we have developed a novel TNFα antagonist, the trimerized fusion protein named sTNFRII-gAD. However, our previously-used CHO expression system yielded less than 10 mg/L of sTNFRII-gAD. To produce large quantities of sTNFRII-gAD efficiently, we used a modified CHO-S cell expression system, which is based on a pMH3 vector with non-coding GC-rich DNA fragments for high-level gene expression. We obtained stable clones that produced 75 mg/L of sTNFRII-gAD in the 96-well plate, adapted the clones to 40 ml suspension serum-free batch culture, then optimized the culturing conditions to scale up the fed-batch culture in a 3 L shake-flask and finally in a 5 L AP30 bioreactor. We achieved a final yield of 52 mg/L of sTNFRII-gAD. The trimerized sTNFRII-gAD exhibited the higher affinity to TNFα with a dissociation constant (Kd) of 5.63 nM than the dimerized sTNFRII-Fc with a Kd of 13.4 nM, and further displayed the higher TNFα-neutralizing activity than sTNFRII-Fc (p<0.05) in a L929 cytotoxicity assay. Therefore, the strategy employed in this study may provide an efficient avenue for large-scale production of other recombinant proteins by use of the modified CHO-S cell expression system

X‑ray Crystal Structure and Optical Properties of Au_{38–<i>x</i>}Cu_<i>x</i>(2,4-(CH₃)₂C₆H₃S)₂₄ (<i>x</i> = 0–6) Alloy Nanocluster

In this work, we report the synthesis and crystal structure of Au_{38–<i>x</i>}­Cu_<i>x</i>­(2,4-DMBT)₂₄ (<i>x</i> = 0–6, 2,4-DMBTH = 2,4-dimethyl­benzene­thiol) alloy nanocluster for the first time. A variety of characterizations including ESI-MS, TGA, and XPS reveal the composition as Au_{38–<i>x</i>}­Cu_<i>x</i>­(2,4-DMBT)₂₄ (<i>x</i> = 0–6). The single crystal structure has been determined by an X-ray single crystal diffractometer. From the anatomy of the structure, a bi-icosahedral Au₂₃ core is protected by six dimeric [−SR–M–SR–M–SR−] units (M = Cu/Au) and three monomeric [−SR–Au–SR−] units. It is interesting that all the Cu atoms are selectively doped in the motifs of the Au_{38–<i>x</i>}­Cu_<i>x</i>­(2,4-DMBT)₂₄ nanocluster. This phenomenon is distinct from the exclusive core doping of the Ag atoms in the previously reported Au_{38–<i>x</i>}­Ag_<i>x</i> alloy. Both the experimental results and DFT calculations of UV–vis spectra imply that the optical property of the Au_{38–<i>x</i>}­Cu_<i>x</i>­(2,4-DMBT)₂₄ nanocluster is consistent with that of the Au₃₈­(2,4-DMBT)₂₄ nanocluster, because the Cu dopants make little contribution to the frontier orbitals of the alloy NC