Study on Amphipathic Modification and QSAR of Volatile Turpentine Analogues as Value-Added Botanical Fungicides against Crop-Threatening Pathogenic Fungi

In view of potential agro activity of turpentine analogues, many studies have been conducted on the application of this biorenewable and abundant natural resource. Three series analogues of derivatives from volatile turpentine were prepared to study suitable amphipathic properties. The evaluation of fungicidal activity was carried out against three pathogenic microbials. In addition to the overall good effect, it was found that compounds 2-hydroxyethyl carboxylate, <b>5k</b>, and 2-(2-hydroxyethoxy)­ethyl carboxylate, <b>5l</b>, demonstrated extreme activity, with IC₅₀ values of 6.013 and 6.610 μg/mL against <i>Setosphaeria turcica</i>, which were close to the control carbendazim. The preliminary structure–activity relationship (SAR) was analyzed, and compounds with appropriate amphipathic features and small steric hindrance displayed more desirable performances. Meanwhile, the quantitative structure–activity relationship (QSAR) model (<i>R</i>² = 0.9548, <i>F</i> = 47.82, <i>S</i>² = 0.0125) was built and indicated that the most two important structural features were the total hybridization composite of the molecular dipole and molecular volumn. Moreover, the study of SAR and QSAR indicated that the structural modification of the amphipathic group, which can regulate the permeabilization property of the molecules, was beneficial to the fungicidal activity. On the basis of this, a potential alternative approach may have been discovered to ensure food safety

Taking Advantage of a Sustainable Forest Resource in Agriculture: A Value-Added Application of Volatile Turpentine Analogues as Botanical Pesticides Based on Amphipathic Modification and QSAR Study

As a continuous study on the integrated application of volatile β-pinene as an abundant bioresource, the further and broader activity assessment of β-pinene analogues was necessary. On the basis of previous research, the larvicidal activities were carried out against two agricultural insect pests <i>Plutella xylostella</i> and <i>Mythimna separata.</i> In accordance with the overall insecticidal effect, it was remarkable that compounds 5k and 5l demonstrated extreme activity, with LC₅₀ values 1.846 and 1.621 μg/mL against <i>Plutella xylostella</i>. The preliminary structure–activity relationship (SAR) was analyzed, and compounds with the appropriate amphipathic feature displayed more desirable performance. In the meantime, the quantitative structure–activity relationship (QSAR) model (<i>R</i>² = 0.9485, <i>F</i> = 82.94, <i>S</i>² = 0.0067) was built. The model indicated the most important structural feature was the μ_c value, which represented the total hybridization components of the molecular dipole. The work provided a potential and alternative approach to take advantage of a forest resource in agriculture

Efficient Control of Rhizoctonia solani Using Environmentally Friendly pH-Responsive Tannic Acid–Rosin Nano-Microcapsules

A nanomicrocapsule system was constructed through the polymerization of tannic acid (TA) and emulsifier OP-10 (OP-10), followed by the chelation of iron ions, to develop a safe and effective method for controlling Rhizoctonia solani in agriculture. The encapsulated active component is a rosin-based triazole derivative (RTD) previously synthesized by our research group (RTD@OP10-TA-Fe). The encapsulation efficiency of the nanomicrocapsules is 82.39%, with an effective compound loading capacity of 96.49%. Through the encapsulation of the RTD via nanomicrocapsules, we improved its water solubility, optimized its stability, and increased its adhesion to the leaf surface. Under acidic conditions (pH = 5.0), the release rate of nanomicrocapsules at 96 h is 96.31 ± 0.8%, which is 2.04 times higher than the release rate under normal conditions (pH = 7.0). Additionally, the results of in vitro and in vivo antifungal assays indicate that compared with the original compound, the nanomicrocapsules exhibit superior antifungal activity (EC50 values of RTD and RTD@OP10-TA-Fe are 1.237 and 0.860 mg/L, respectively). The results of field efficacy trials indicate that compared with RTD, RTD@OP10-TA-Fe exhibits a more prolonged period of effectiveness. Even after 3 weeks, the antifungal rate of RTD@OP10-TA-Fe remains at 40%, whereas RTD, owing to degradation, shows an antifungal rate of 11.11% during the same period. Furthermore, safety assessment results indicate that compared with the control, RTD@OP10-TA-Fe has almost no impact on the growth of rice seedlings and exhibits low toxicity to zebrafish. This study provides valuable insights into controlling R. solani and enhancing the compound performance

Unique 5′-P recognition and basis for dG:dGTP misincorporation of ASFV DNA polymerase X

<div><p>African swine fever virus (ASFV) can cause highly lethal disease in pigs and is becoming a global threat. ASFV DNA Polymerase X (<i>Asfv</i>PolX) is the most distinctive DNA polymerase identified to date; it lacks two DNA-binding domains (the thumb domain and 8-KD domain) conserved in the homologous proteins. <i>Asfv</i>PolX catalyzes the gap-filling reaction during the DNA repair process of the ASFV virus genome; it is highly error prone and plays an important role during the strategic mutagenesis of the viral genome. The structural basis underlying the natural substrate binding and the most frequent dG:dGTP misincorporation of <i>Asfv</i>PolX remain poorly understood. Here, we report eight <i>Asfv</i>PolX complex structures; our structures demonstrate that <i>Asfv</i>PolX has one unique 5′-phosphate (5′-P) binding pocket, which can favor the productive catalytic complex assembly and enhance the dGTP misincorporation efficiency. In combination with mutagenesis and in vitro catalytic assays, our study also reveals the functional roles of the platform His115-Arg127 and the hydrophobic residues Val120 and Leu123 in dG:dGTP misincorporation and can provide information for rational drug design to help combat ASFV in the future.</p></div

Age distribution among different HCV subtypes^a.

<p>Age distribution among different HCV subtypes<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0161844#t003fn001" target="_blank">^a</a>.</p

The impacts of the H115-Arg127 platform on the dG:dGTP misincorporation.

<p>The dC:dGTP and dG:dGTP base pairs observed in (<b>A</b>) <i>Asfv</i>PolX:1nt-gap(P) DNA5:dGTP structure and (<b>B</b>) <i>Asfv</i>PolX:1nt-gap(P) DNA6:dGTP structure, respectively. The 2F_o-F_c maps are contoured at 1.5 σ level. (<b>C</b>) Quantification and comparison of in vitro dG:dGTP misincorporation assay catalyzed by WT <i>Asfv</i>PolX, H115D, H115E, H115F, R127A, and H115F/R127A mutants (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1002599#pbio.1002599.s001" target="_blank">S1 Data</a>). The data represent the mean of three independent experiments with SD values indicated by error bars. The dG:dGTP and dT:ddA base pairs observed at the insertion and postinsertion sites of (<b>D</b>) H115F/R127A:1nt-gap(P) DNA6:dGTP and (<b>E</b>) H115F:1nt-gap(P) DNA6:dGTP, respectively. (<b>F</b>) Structural comparison showing the conformational differences between <i>Asfv</i>PolX:1nt-DNA(P) DNA6:dGTP and H115F:1nt-gap(P) DNA6:dGTP. For clarity, the insertion site dG:dGTP base pairs and the <i>Asfv</i>PolX protein in <i>Asfv</i>PolX:1nt-gap(P) DNA6:dGTP structure are omitted. The C atoms of Phe115, Arg127, and the postinsertion site dT:ddA of H115F:1nt-gap(P) DNA6:dGTP are colored green in both (<b>E</b>) and (<b>F</b>), whereas, the C atoms are colored white for His115, Arg127, and for the postinsertion site dT:ddA of <i>Asfv</i>PolX:1nt-gap(P) DNA6:dGTP in (<b>F</b>).</p

K_d values for the DNA binding to <i>Asfv</i>PolX and mutants.

<p>K_d values for the DNA binding to <i>Asfv</i>PolX and mutants.</p

5′-P of downstream oligo facilitates the productive complex assembly.

<p>(<b>A</b>) Sequence of 1nt-gap DNA4 and the overall structure of <i>Asfv</i>PolX:1nt-gap DNA4 complex. <i>Asfv</i>PolX is shown as a cartoon with the palm and finger domains colored in cyan and white, respectively. The template strand, primer, and downstream oligo are shown as stick with the C atoms colored in green, yellow, and yellow, respectively. The template residue (G8) is indicated with arrow. (<b>B</b>) Sequences of 2nt-gap(P) DNA5 and 1nt-gap(P) DNA5. (<b>C</b>) Overall structure of <i>Asfv</i>PolX:1nt-gap(P) DNA5:dGTP. <i>Asfv</i>PolX is shown as cartoon with palm and finger domains colored in cyan and white, respectively. DNA is shown as sticks with the C atoms colored in yellow, green, and green, for the template strand, primer, and downstream oligo, respectively. dGTP is also shown as sticks, Mn²⁺ ions are shown as red spheres.</p

Characteristics and genotypes of HCV in patients with HIV/HCV co-infection^a.

<p>Characteristics and genotypes of HCV in patients with HIV/HCV co-infection<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0161844#t001fn002" target="_blank">^a</a>.</p

Phylogenetic trees of HCV NS5B gene of patients with HIV/HCV co-infection.

<p>There were 5 HCV genotypes and 10 subtypes identified in our studied population, but their frequencies were not equally distributed amongst the group.</p