Application of Sustainable Natural Bioesources in Crop Protection: Insight into a Podophyllotoxin-Derived Botanical Pesticide for Regulating Insect Vestigial Wing of <i>Mythimna separata</i> Walker

In continuation of our program for integrated application of podophyllotoxin (isolated from <i>Juniperus Sabina</i>) as a forest sustainable natural resource in crop protection, an in-depth study on the mechanism of action of podophyllotoxin derivatives as botanical pesticides was necessary. On the basis of our previous results, here the transcriptional response of vestigial wing in <i>Mythimna separata</i> Walker (a crop-threatening insect pest) to a podophyllotoxin-derived insecticidal agent was analyzed by using RNA-Seq. This is the first study to explore the vestigial wing behavior of insect pests caused by xenobiotics. These results suggested that this agent could suppress wing-related development pathways, such as the insulin signaling pathway, juvenile hormone biosynthesis, wing disc morphogenesis, wing disc development, and imaginal disc-derived wing morphogenesis; it markedly repressed wing development-related genes of <i>insulin receptor</i>, <i>insulin-like precursor polypeptide D, juvenile hormone, engrailed-like, vestigial-like, serrate homologue, notch</i>, and <i>distalless homebox</i>, and activated wing development-related genes of <i>indian hedgehog and spalt major-like</i>, validated by qRT-PCR. Our results will pave the way for a future application of this sustainable forest natural bioresource as a crop protection agent to control insect pests damage in agriculture

CIFOR Poverty and Environment Network (PEN)

As a guardian of the bacterial genome, the RecG DNA helicase repairs DNA replication and rescues stalled replication. We applied atomic force microscopy (AFM) to directly visualize dynamics of RecG upon the interaction with replication fork substrates in the presence and absence of SSB using high-speed AFM. We directly visualized that RecG moves back and forth over dozens of base pairs in the presence of SSB. There is no RecG translocation in the absence of SSB. Computational modeling was performed to build models of <i>Escherichia coli</i> RecG in a free state and in complex with the fork. The simulations revealed the formation of complexes of RecG with the fork and identified conformational transitions that may be responsible for RecG remodeling that can facilitate RecG translocation along the DNA duplex. Such complexes do not form with the DNA duplex, which is in line with experimental data. Overall, our results provide mechanistic insights into the modes of interaction of RecG with the replication fork, suggesting a novel role of RecG in the repair of stalled DNA replication forks

Dynamics of the Interaction of RecG Protein with Stalled Replication Forks

As a guardian of the bacterial genome, the RecG DNA helicase repairs DNA replication and rescues stalled replication. We applied atomic force microscopy (AFM) to directly visualize dynamics of RecG upon the interaction with replication fork substrates in the presence and absence of SSB using high-speed AFM. We directly visualized that RecG moves back and forth over dozens of base pairs in the presence of SSB. There is no RecG translocation in the absence of SSB. Computational modeling was performed to build models of <i>Escherichia coli</i> RecG in a free state and in complex with the fork. The simulations revealed the formation of complexes of RecG with the fork and identified conformational transitions that may be responsible for RecG remodeling that can facilitate RecG translocation along the DNA duplex. Such complexes do not form with the DNA duplex, which is in line with experimental data. Overall, our results provide mechanistic insights into the modes of interaction of RecG with the replication fork, suggesting a novel role of RecG in the repair of stalled DNA replication forks

Dynamics of the Interaction of RecG Protein with Stalled Replication Forks

As a guardian of the bacterial genome, the RecG DNA helicase repairs DNA replication and rescues stalled replication. We applied atomic force microscopy (AFM) to directly visualize dynamics of RecG upon the interaction with replication fork substrates in the presence and absence of SSB using high-speed AFM. We directly visualized that RecG moves back and forth over dozens of base pairs in the presence of SSB. There is no RecG translocation in the absence of SSB. Computational modeling was performed to build models of <i>Escherichia coli</i> RecG in a free state and in complex with the fork. The simulations revealed the formation of complexes of RecG with the fork and identified conformational transitions that may be responsible for RecG remodeling that can facilitate RecG translocation along the DNA duplex. Such complexes do not form with the DNA duplex, which is in line with experimental data. Overall, our results provide mechanistic insights into the modes of interaction of RecG with the replication fork, suggesting a novel role of RecG in the repair of stalled DNA replication forks

L'Auto-vélo : automobilisme, cyclisme, athlétisme, yachting, aérostation, escrime, hippisme / dir. Henri Desgranges

29 janvier 19431943/01/29 (A44,N15335)

Dynamics of the Interaction of RecG Protein with Stalled Replication Forks

As a guardian of the bacterial genome, the RecG DNA helicase repairs DNA replication and rescues stalled replication. We applied atomic force microscopy (AFM) to directly visualize dynamics of RecG upon the interaction with replication fork substrates in the presence and absence of SSB using high-speed AFM. We directly visualized that RecG moves back and forth over dozens of base pairs in the presence of SSB. There is no RecG translocation in the absence of SSB. Computational modeling was performed to build models of <i>Escherichia coli</i> RecG in a free state and in complex with the fork. The simulations revealed the formation of complexes of RecG with the fork and identified conformational transitions that may be responsible for RecG remodeling that can facilitate RecG translocation along the DNA duplex. Such complexes do not form with the DNA duplex, which is in line with experimental data. Overall, our results provide mechanistic insights into the modes of interaction of RecG with the replication fork, suggesting a novel role of RecG in the repair of stalled DNA replication forks

Identification of Novel Knockout Targets for Improving Terpenoids Biosynthesis in <i>Saccharomyces cerevisiae</i>

<div><p>Many terpenoids have important pharmacological activity and commercial value; however, application of these terpenoids is often limited by problems associated with the production of sufficient amounts of these molecules. The use of <i>Saccharomyces cerevisiae</i> (<i>S. cerevisiae</i>) for the production of heterologous terpenoids has achieved some success. The objective of this study was to identify <i>S. cerevisiae</i> knockout targets for improving the synthesis of heterologous terpeniods. On the basis of computational analysis of the <i>S. cerevisiae</i> metabolic network, we identified the knockout sites with the potential to promote terpenoid production and the corresponding single mutant was constructed by molecular manipulations. The growth rates of these strains were measured and the results indicated that the gene deletion had no adverse effects. Using the expression of amorphadiene biosynthesis as a testing model, the gene deletion was assessed for its effect on the production of exogenous terpenoids. The results showed that the dysfunction of most genes led to increased production of amorphadiene. The yield of amorphadiene produced by most single mutants was 8–10-fold greater compared to the wild type, indicating that the knockout sites can be engineered to promote the synthesis of exogenous terpenoids.</p></div

Ultra-large-scale Synthesis of Fe₃O₄ Nanoparticles and Their Application for Direct Coal Liquefaction

Ultra-large-scale synthesis of iron oxide nanoparticles (875 g) has been achieved in a single reaction via a facile solution-based dehydration process. The obtained nanoparticles capped with hydrophobic oleic acid ligands are magnetite with the average size of 5 nm. The synthesized samples exhibit a higher catalytic activity toward the direct coal liquefaction (DCL) than the commercial Fe₃O₄ powders. The conversion, oil yield, and liquefaction degree with the synthesized Fe₃O₄ nanoparticles are 89.6, 65.1, and 77.3%, respectively. The excellent catalytic performance of the synthesized Fe₃O₄ nanoparticles can be attributed to their extremely small size and high dispersity. This facile approach to prepare highly active nanocatalyst for the DCL will be applicable for future industrial processes

Comparison of yeast cell growth (A) and amorphadiene production (B) between the single mutant YS5, the double mutant YD1 and the wild type strain WAT11.

<p>Comparison of yeast cell growth (A) and amorphadiene production (B) between the single mutant YS5, the double mutant YD1 and the wild type strain WAT11.</p

Air-Stable Salen–Iron Complexes: Stereoselective Catalysts for Lactide and ε‑Caprolactone Polymerization through <i>in Situ</i> Initiation

A series of iron­(III) chloride complexes based upon Schiff base framework have been synthesized and characterized by mass spectra, elemental analysis, and X-ray crystallography. These bench-stable complexes were for the first time capable as highly efficient catalysts for lactide and ε-caprolactone polymerization in the presence of propylene oxide (PO), greatly surpassing conventional aluminum analogies. Electron-withdrawing substituents as well as elevated temperature boosted the activity while a bulky group on salicylaldehyde moieties abnormally produces the same effect, whereas rigid backbone retarded the reactivity. Polylactide tactics ranging from isotactic to hererotactic enchainment were obtained by tuning the ligand backbone and substituents. The stereoselectivity was confirmed to proceed via a chain-end control mechanism by kinetic studies using different isomers of lactide, and the overall polymerization process was also investigated in detail by the oligomer mass spectrum as well as end group (−OCHMeCH₂Cl) analysis of polymer via ¹H, ¹³C, and two-dimensional (2-D) NMR characterizations