Light influences the effect of exogenous ethylene on the phenolic composition of Cabernet Sauvignon grapes

The gaseous phytohormone ethylene (ETH) plays a key role in plant growth and development, and is a major regulator of phenolic biosynthesis. Light has long been known to influence phytohormone signaling transduction. However, whether light influences the effect of ETH on the phenolic composition of grapes (Vitis vinifera L.) is an open question. Here, the accumulation and composition of anthocyanins and non-anthocyanin phenolics were analyzed in Cabernet Sauvignon grapes under four treatments: light exposure with and without ETH treatment, and box-shading with and without ETH treatment. Both light and ETH promoted ripening, decreased the color index (L*, C*, and h*), and accelerated the color change from green to red and purplish red. Sunlight-exposed grapes had the highest contents of most anthocyanins, flavonols, flavan-3-ols, and hydroxybenzoic acids. In addition, light exposure increased the ratios of 3’5’-substituted/3’-substituted anthocyanins and flavonols, but decreased the ratios of methoxylated/non-methoxylated and acylated/non-acylated anthocyanins and flavan-3-ols. Notably, the effects of ETH were influenced by light exposure. Specifically, ETH treatment promoted anthocyanin and non-anthocyanin biosynthesis in light-exposed grapes, and their increasing multiples were remarkably higher under light-exposed conditions. Furthermore, ETH treatment decreased the ratios of methoxylated/non-methoxylated, 3’5’-substituted/3’-substituted, and acylated/non-acylated anthocyanins and flavan-3-ols in light-exposed grapes, each of which was increased by ETH treatment in shaded grapes. Fifteen differential phenolic components were identified through partial least-squares-discriminant analysis (PLS-DA). Among them, cyanidin-3-O-(cis-6-O-coumaryl)-glucoside, petunidin-3-O-(6-O-acetyl)-glucoside, petunidin-3-O-(trans-6-O-coumaryl)-glucoside, petunidin-3-O-glucoside, myricetin-3-O-galactoside, kaempferol-3-O-galactoside, and kaempferol-3-O-glucoside were the main differential components between ETH treatments under different light conditions. This study contributes to the understanding of the impact of ethylene treatment under dark and light conditions on phenolic synthesis in grape berries

Efficient production of human acidic fibroblast growth factor in pea (Pisum sativum L.) plants by agroinfection of germinated seeds

<p>Abstract</p> <p>Background</p> <p>For efficient and large scale production of recombinant proteins in plants transient expression by agroinfection has a number of advantages over stable transformation. Simple manipulation, rapid analysis and high expression efficiency are possible. In pea, Pisum sativum, a Virus Induced Gene Silencing System using the pea early browning virus has been converted into an efficient agroinfection system by converting the two RNA genomes of the virus into binary expression vectors for Agrobacterium transformation.</p> <p>Results</p> <p>By vacuum infiltration (0.08 Mpa, 1 min) of germinating pea seeds with 2-3 cm roots with <it>Agrobacteria </it>carrying the binary vectors, expression of the gene for Green Fluorescent Protein as marker and the gene for the human acidic fibroblast growth factor (aFGF) was obtained in 80% of the infiltrated developing seedlings. Maximal production of the recombinant proteins was achieved 12-15 days after infiltration.</p> <p>Conclusions</p> <p>Compared to the leaf injection method vacuum infiltration of germinated seeds is highly efficient allowing large scale production of plants transiently expressing recombinant proteins. The production cycle of plants for harvesting the recombinant protein was shortened from 30 days for leaf injection to 15 days by applying vacuum infiltration. The synthesized aFGF was purified by heparin-affinity chromatography and its mitogenic activity on NIH 3T3 cells confirmed to be similar to a commercial product.</p

Metabolism of androstenone, 17β-estradiol and dihydrotestosterone in primary cultured pig hepatocytes and the role of 3β-hydroxysteroid dehydrogenase in this process

© 2015 Chen et al. Steroids metabolism plays an important role in mammals and contributes to quality of pig meat. The main objective of this study was to identify metabolites of androstenone, 17β-estradiol and dihydrotestosterone using primary cultured pig hepatocytes as a model system. The role of 3β-hydroxysteroid dehydrogenase (3βHSD) in regulation of steroid metabolism was also validated using trilostane, a specific 3βHSD inhibitor. Steroid glucuronide conjugated metabolites were detected by liquid chromatography time of flight mass spectrometry (LC-TOF-MS). 3βHSD enzyme was essential for metabolism of androstenone to 5α-androst-16-en-3β-ol, which then formed androstenone glucuronide conjugate. Metabolism of 17β-estradiol was accompanied by formation of glucuronide-conjugated estrone and glucuronide-conjugated estradiol. The ratio of the two metabolites was around 5:1. 3βHSD enzyme was not involved in 17β-estradiol metabolism. 5α-Dihydrotestosterone-17β-glucuronide was identified as a dihydrotestosterone metabolite, and this metabolism was related to 3βHSD enzyme activity as demonstrated by inhibition study

Pleiotropic effects of the twin-arginine translocation system on biofilm formation, colonization, and virulence in Vibrio cholerae

<p>Abstract</p> <p>Background</p> <p>The Twin-arginine translocation (Tat) system serves to translocate folded proteins, including periplasmic enzymes that bind redox cofactors in bacteria. The Tat system is also a determinant of virulence in some pathogenic bacteria, related to pleiotropic effects including growth, motility, and the secretion of some virulent factors. The contribution of the Tat pathway to <it>Vibrio cholerae </it>has not been explored. Here we investigated the functionality of the Tat system in <it>V. cholerae</it>, the etiologic agent of cholera.</p> <p>Results</p> <p>In <it>V. cholerae</it>, the <it>tatABC </it>genes function in the translocation of TMAO reductase. Deletion of the <it>tatABC </it>genes led to a significant decrease in biofilm formation, the ability to attach to HT-29 cells, and the ability to colonize suckling mouse intestines. In addition, we observed a reduction in the output of cholera toxin, which may be due to the decreased transcription level of the toxin gene in <it>tatABC </it>mutants, suggesting an indirect effect of the mutation on toxin production. No obvious differences in flagellum biosynthesis and motility were found between the <it>tatABC </it>mutant and the parental strain, showing a variable effect of Tat in different bacteria.</p> <p>Conclusion</p> <p>The Tat system contributes to the survival of <it>V. cholerae </it>in the environment and <it>in vivo</it>, and it may be associated with its virulence.</p

The reliability of colorimetry is precise(ly) as expected.

Figure S6. Gene ontology (GO) analysis of the differentially expressed genes between C1 and C2. (JPG 403 kb

Reveal a hidden highly toxic substance in biochar to support its effective elimination strategy

With the aim to develop optimized biochar with minimal contaminants, it is important significance to broaden the understanding of biochar. Here, we disclose for the first time, a highly toxic substance (metal cyanide, MCN, such as KCN or NaCN) in biochar. The cyanide ion (CN−) content in biochar can be up to 85,870 mg/kg, which is determined by the inherent metal content and type in the biomass with K and Na increasing and Ca, Mg and Fe decreasing its formation. Density functional theory (DFT) analysis shows that unstable alkali oxygen-containing metal salts such as K2CO3 can induce an N rearrangement reaction to produce for example, KOCN. The strong reducing character of the carbon matrix further converts KOCN to KCN, thus resulting biochar with high risk. However, the stable Mg, Ca and Fe salts in biomass cannot induce an N rearrangement reaction due to their high binding energies. We therefore propose that high valent metal chloride salts such as FeCl3 and MgCl2 could be used to inhibit the production of cyanide via metal interactive reaction. These findings open a new point of view on the potential risk of biochar and provide a mitigation solution for biochar’s sustainable application

Broadening of Neutralization Activity to Directly Block a Dominant Antibody-Driven SARS-Coronavirus Evolution Pathway

Phylogenetic analyses have provided strong evidence that amino acid changes in spike (S) protein of animal and human SARS coronaviruses (SARS-CoVs) during and between two zoonotic transfers (2002/03 and 2003/04) are the result of positive selection. While several studies support that some amino acid changes between animal and human viruses are the result of inter-species adaptation, the role of neutralizing antibodies (nAbs) in driving SARS-CoV evolution, particularly during intra-species transmission, is unknown. A detailed examination of SARS-CoV infected animal and human convalescent sera could provide evidence of nAb pressure which, if found, may lead to strategies to effectively block virus evolution pathways by broadening the activity of nAbs. Here we show, by focusing on a dominant neutralization epitope, that contemporaneous- and cross-strain nAb responses against SARS-CoV spike protein exist during natural infection. In vitro immune pressure on this epitope using 2002/03 strain-specific nAb 80R recapitulated a dominant escape mutation that was present in all 2003/04 animal and human viruses. Strategies to block this nAb escape/naturally occurring evolution pathway by generating broad nAbs (BnAbs) with activity against 80R escape mutants and both 2002/03 and 2003/04 strains were explored. Structure-based amino acid changes in an activation-induced cytidine deaminase (AID) “hot spot” in a light chain CDR (complementarity determining region) alone, introduced through shuffling of naturally occurring non-immune human VL chain repertoire or by targeted mutagenesis, were successful in generating these BnAbs. These results demonstrate that nAb-mediated immune pressure is likely a driving force for positive selection during intra-species transmission of SARS-CoV. Somatic hypermutation (SHM) of a single VL CDR can markedly broaden the activity of a strain-specific nAb. The strategies investigated in this study, in particular the use of structural information in combination of chain-shuffling as well as hot-spot CDR mutagenesis, can be exploited to broaden neutralization activity, to improve anti-viral nAb therapies, and directly manipulate virus evolution