Spartina alterniflora, a perennial grass with C(4)-photosynthesis, shows great invading potential in the coastal ecosystems in the east of China. We compared trace gas emissions from S. alterniflora ...with those from a native C(3) plant, Phragmites australis, by establishing brackish marsh mesocosms to experimentally assess the effects of plant species (S. alterniflora vs. P. australis), flooding status (submerged vs. non-submerged), and clipping (plants clipped or not) on trace gas emissions. The results show that trace gas emission rates were higher in S. alterniflora than P. australis mesocosms due to the higher biomass and density of the former, which could fix more available substrates to the soil and potentially emit more trace gases. Meanwhile, trace gas emission rates were higher in non-submerged than submerged soils, suggesting that water might act as a diffusion barrier in the brackish marsh mesocosms. Interestingly, methane (CH(4)) emission rates were lower in clipped non-submerged mesocosms than in non-clipped submerged mesocosms, but nitrous oxide (N(2)O) emissions were enhanced. CH(4) emissions were significantly correlated with the plant biomass and stem density (R(2)>0.48, P<0.05) for both species, suggesting that both the two species might play important roles in CH(4) production and transport and also act as suppliers of easily available substrates for the methanogenic bacteria in wetland ecosystems. N(2)O emissions, however, were not significantly correlated with plant biomass and density (P>0.05).
A novel method involving the fabrication of Mo–W mixed oxide (Mo x W1–x O3) is proposed to modify the modest reaction kinetics and poor cycling stability of MoO3 material. By a simple ...coelectrodeposition method, a series of Mo x W1–x O3 oxides is deposited on a TiO2 nanotube array substrate. Because of the differences between Mo6+ and W6+ in nature, there is significant distortion existing in the mixed oxides, leading to their decreased crystallite size and enlarged lattice space, which facilitates ion diffusion in the solid. As results, the mixed oxides show much better balance between specific capacitance and cycling stability than the bare MoO3 or WO3 sample, which suffers from either poor cycling stability or low electrochemical activity. Impressively, the optimal Mo–W mixed oxide exhibits a high specific capacitance of 517.4 F g–1 at 1 A g–1, and, moreover, it retains 89.3% of the capacitance even at a high current density of 10 A g–1, demonstrating ultrahigh rate capability. These findings reveal the potential of the Mo–W mixed oxide for constructing advanced ultrahigh power supercapacitors.
Protein design for improving enzymatic activity remains a challenge in biochemistry, especially to identify target amino-acid sites for mutagenesis and to design beneficial mutations for those sites. ...Here, we employ a computational approach that combines multiple sequence alignment, positive selection detection, and molecular docking to identify and design beneficial amino-acid mutations that further improve the intramolecular-cyclization activity of a chalcone-flavonone isomerase from
(GmCHI). By this approach, two GmCHI mutants with higher activities were predicted and verified. The results demonstrate that this approach could determine the beneficial amino-acid mutations for improving the enzymatic activity, and may find more applications in engineering of enzymes.
Isoflavonoids are a group of phenolic secondary metabolites found almost exclusively in leguminous plants. Formononetin, calycosin and calycosin‐7‐O‐β‐d‐glucoside (CG) are isoflavonoid products in ...the CG pathway. Accumulation of the three isoflavonoids plus daidzein and expression of six genes of enzymes involved in the CG pathway were studied in Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao with ultraviolet (UV) irradiation. Our results showed that (1) main isoflavonoids in roots, stems and leaves were CG, daidzein and calycosin, respectively; they accumulated significantly under the induction of UV irradiation during 8 days but their content declined later; (2) expression of six genes of enzymes involved in the CG pathway was inhibited slightly at early stage but the expression was increased greatly afterward; (3) chalcone synthase, chalcone reductase and chalcone isomerase were expressed to their individual maximum level within shorter hours than were cinnamate 4‐hydroxylase, isoflavone synthase (IFS) and isoflavone 3′‐hydroxylase and (4) more calycosin but less daidzein accumulated in leaves. IFS was highly expressed in leaves, which might lead to high accumulation of the common precursor of daidzein and 2,7‐dihydroxy‐4′‐O‐methoxy‐isoflavanone, the latter of which would be converted to formononetin, calycosin and CG via a series of reactions. Little daidzein accumulated in leaves, which suggested that rather than be converted to daidzein, the 2,7,4′‐trihydroxyisoflavanone was probably more easily caught by 2‐hydroxyisoflavanone 4′‐O‐methyltransferase and hence provided more precursors for formononetin. The findings were discussed in terms of the influence of UV irradiation in the accumulation of isoflavonoids.
It is well known that non-small cell lung cancer (NSCLC) is a malignant tumor with high incidence in the world. We aimed to clarify a possible target and identify its precise molecular biological ...mechanism in NSCLC. NLR family CARD domain containing 5 (NLRC5) is widely expressed in tissues and exerts a vital role in anti-tumor immunity. We determined NLRC5 expression by RT-qPCR and western blot assay. The role of NLRC5 in the development of NSCLC was assessed by a loss-of-function assay. CCK-8, Annexin-V-FITC/PI Apoptosis Detection Kit, Transwell, and wound healing assays were used to determine the cell functions. Drug resistance-related proteins were analyzed by western blot assay. Furthermore, the modulation of NLRC5 on carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) expression and subsequent PI3K/AKT signaling was assessed. In this study, a hyper-expression of NLRC5 was found in NSCLC tissues and cell lines. Knockdown of NLRC5 suppressed cell viability, invasion, and migration, and furthermore promoted cell apoptosis in NSCLC cells. Moreover, under normoxia or hypoxia treatment, the upregulation of NLRC5 was related to carboplatin resistance. NLRC5 silencing increased carboplatin-resistant cell chemosensitivity, as evidenced by the increase in the cell inhibition rate and decrease in drug resistance-related protein expression. Mechanistically, NLRC5 knockdown inhibited the expression of CEACAM1 and subsequently blocked the PI3K/AKT signaling pathway. In conclusion, NLRC5 promotes the malignant biological behaviors of NSCLC cells by activating the PI3K/AKT signaling pathway via the regulation of CEACAM1 expression under normoxia and hypoxia.
•We succeeded in cloning the AmI2′H gene.•We modified the ORF sequence of this plant P450 protein to facilitate its expression and solubility using gene engineering techniques.•The pET 28a_AmI2′H was ...better than pCW_AmI2′H in both expression efficiency and purity.
Plant cytochrome P450 enzymes play vital roles in the biosynthesis of plant secondary metabolites, including phenylpropanoids and phytoalexins. Isoflavone-2′-hydroxylase (AmI2′H) from Astragalus membranaceus Bge. Var. mongolicus (Bge.) Hsiao is a membrane protein and an eukaryotic cytochrome P450 enzyme involved in isoflavonoid biosynthesis. We cloned the AmI2′H gene by employing RACE methods and modified the gene sequence to facilitate protein expression and increase protein solubility. Two vectors, pET-28a(+) and pCW ori(+), were used to express AmI2′H in Escherichia coli. The expression efficiency and purity of target protein were analyzed and demonstrated that pET-28a(+) vector containing the AmI2′H gene could produce larger amounts of target proteins with higher purity than pCWori(+). The purified proteins were identified as AmI2′H by LC–ESI-MS/MS analysis and their proper folding was assessed by CO difference spectrum.
Previously it had been shown that calycosin and calycosin-7-O-β-D-glucoside (CGs) accumulate in whole plants, mainly in leaves, of Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao (A. ...mongholicus) plants in response to low temperature. In this work, it was demonstrated that the influences of different conditions on CGs biosynthesis, by examining the changes in CGs content, as well as the expression of related genes, including phenylalanine ammonia lyase (PAL1), cinnamic acid 4-hydroxylase (C4H), chalcone synthase (CHS), chalcone reductase (CHR), chalcone isomerase (CHI), isoflavone synthase (IFS), and isoflavone 3′-hydroxylase (I3′H). The seven gene mRNAs accumulated in leaves of A. mongholicus upon exposure to low temperature in a light-dependent manner, though they exhibited different expression patterns. Transcriptions of CHS, CHR, CHI, IFS, and I3′H of the calycosin-7-O-β-D-glucoside pathway were all up-regulated when plants were transferred from 16 °C to 2 °C or 25 °C or from 2 °C (kept for 24 h) to 25 °C. However, fluctuations in temperature influenced differently the transcriptions of PAL1 and C4H of the general phenylpropanoid pathway in leaves. Moreover, the amount of PAL1 expression changed sharply up and down, consistent with the variation of the content of CGs. PAL enzyme activity appears to be the limiting factor in determining the CGs levels. The inhibitor of PAL enzyme, L-α-aminooxy-β-phenylpropionic acid, almost entirely shut down CGs accumulation at low temperature. All these results confirmed that PAL1, as a smart gene switch, directly controls the accumulation of CGs in A. mongholicus plants, in a light-dependent manner, during low temperature treatment.
To explore the clinical efficacy and safety of gastroepiploic tunnel esophagogastrostomy applied in minimally invasive esophagectomy and gastroesophageal cervical anastomosis.
Clinical data of 137 ...esophageal cancer patients who received minimally invasive esophagectomy from December 2013 to June 2015 in Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University were analyzed retrospectively, including 84 patients receiving anastomosis with tubular anastomat (circular staple group), and 53 patients receiving gastroepiploic tunnel anastomosis(tunnel group, position of tunnel anastomosis located in the side of gastrocolic omentum, about 2-3 cm apart from fundus). Incidence of postoperative anastomotic leakage and stricture was compared between two groups.
All the 137 patients completed minimally invasive esophageal surgeries successfully without conversion to open thoracic or abdominal operation. The time for anastomosis was(20.2±3.1) minutes in circular stapler group and (38.9±2.9)
A chalcone reductase (CHR) gene was isolated from
Astragalus membranaceus
Bge. var.
mongholicus
(Bge.) Hsiao (
A. mongholicus
). The full-length cDNA of
A. mongholicus
CHR, designated as
Amchr
...(GenBank accession No. HM357239), was 1196 bp long. It had a 957 bp open reading frame encoding a 318-amino acid protein of 35 kDa, a 67 bp 5′ non-coding region and a 172 bp 3′-untranslated region. The putative AmCHR protein showed striking similarity to CHR from other leguminous species. Two-dimensional structure modeling showed that AmCHR consisted of 45.28% α-helix, 10.38% extended strand and 44.34% random coil. Prediction showed that three-dimensional AmCHR was a global protein containing an aldo-ket-red domain, with a putative Asp-Tyr-Lys-His catalytic tetrad in the center. The AmCHR gene was 1251 bp long, consisting of three exons and two introns. Intron I was 125 bp and intron II was 169 bp long. Southern blot analysis indicated that
Amchr
belonged to a small multigene family. Under natural conditions,
Amchr
was expressed differentially in the root, stem and leaf tissues of
A. mongholicus
, with a preferential expression in the root. The recombinant AmCHR protein was successfully expressed in
Escherichia coli
strain BL21 with pET42a vector. The result showed that the expressed AmCHR protein had molecular weight of about 35 kDa, which matched the size of the predicted protein by bioinformatic analysis. This study opened avenues towards understanding of the function of AmCHR protein and the role of the
Amchr
gene in the calycosin-7-
O
-β-
d
-glucoside branch pathway in
A. mongholicus
.
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