Design, Synthesis, and Evaluation of New Sulfone Derivatives Containing a 1,3,4-Oxadiazole Moiety as Active Antibacterial Agents

This study aimed to synthesize some new sulfone derivatives containing a 1,3,4-oxadiazole moiety and investigate their in vitro antibacterial activities against <i>Xanthomonas oryzae</i> pv. <i>oryzae</i> (<i>Xoo</i>) and <i>Xanthomonas axonopodis</i> pv. <i>citri</i> (<i>Xac</i>), the pathogens of rice bacterial leaf blight and citrus canker, respectively, by performing turbidimeter tests. Antibacterial bioassay results showed that compound <b>6d</b> revealed excellent bioactivities against <i>Xoo</i> and <i>Xac</i>, with the 50% effective concentration (EC₅₀) values of 0.17 and 1.98 μg/mL, respectively, compared with thiodiazole copper (121.82 and 77.04 μg/mL, respectively) and bismerthiazol (92.61 and 58.21 μg/mL, respectively). Meanwhile, greenhouse-condition trials indicated that, compared with thiodiazole copper and bismerthiazol, compound <b>6d</b> more effectively reduced rice bacterial leaf blight

Data_Sheet_1_Diversity of endosymbionts in camellia spiny whitefly, Aleurocanthus camelliae (Hemiptera: Aleyrodidae), estimated by 16S rRNA analysis and their biological implications.docx

Camellia spiny whitefly, Aleurocanthus camelliae (Hemiptera: Aleyrodidae), is a major pest in tea, which poses a serious threat to tea production. Similar to many insects, various bacterial symbioses inside A. camelliae may participate in the reproduction, metabolism, and detoxification of the host. However, few reports included research on the microbial composition and influence on A. camelliae growth. We first applied high-throughput sequencing of the V4 region in the 16S rRNA of symbiotic bacteria to study its component and effect on the biological trait of A. camelliae by comparing it with the antibiotic treatment group. The population parameters, survival rate, and fecundity rate of A. camelliae were also analyzed using the age–stage two-sex life table. Our results demonstrated that phylum Proteobacteria (higher than 96.15%) dominated the whole life cycle of A. camelliae. It unveiled the presence of Candidatus Portiera (primary endosymbiont) (67.15–73.33%), Arsenophonus (5.58–22.89%), Wolbachia (4.53–11.58%), Rickettsia (0.75–2.59%), and Pseudomonas (0.99–1.88%) genus. Antibiotic treatment caused a significant decrease in the endosymbiont, which negatively affected the host's biological properties and life process. For example, 1.5% rifampicin treatment caused a longer preadult stage in the offspring generation (55.92 d) compared to the control (49.75d) and a lower survival rate (0.36) than the control (0.60). The decreased intrinsic rate of increase (r), net reproductive rate (R0), and prolonged mean generation time (T) were signs of all disadvantageous effects associated with symbiotic reduction. Our findings confirmed the composition and richness of symbiotic bacteria in larva and adult of A. camelliae by an Illumina NovaSeq 6000 analysis and their influence on the development of the host by demographic research. Together, the results suggested that symbiotic bacteria play an important role in manipulating the biological development of their hosts, which might help us for developing new pest control agents and technologies for better management of A. camelliae.</p

Synthesis and Antiviral Bioactivity of Novel 3‑((2-((1<i>E</i>,4<i>E</i>)‑3-Oxo-5-arylpenta-1,4-dien-1-yl)phenoxy)methyl)-4(3<i>H</i>)‑quinazolinone Derivatives

A series of novel 3-((2-((1<i>E</i>,4<i>E</i>)-3-oxo-5-arylpenta-1,4-dien-1-yl)­phenoxy)­methyl)-4­(3<i>H</i>)-quinazolinone derivatives were designed and synthesized. Antiviral bioassays indicated that a few of the compounds exhibited higher antiviral activities against tobacco mosaic virus (TMV) in vivo than the commercial agent ningnanmycin. In particular, compounds <b>A</b>_<b>5</b>, <b>A</b>_<b>12</b>, <b>A</b>_<b>25</b>, and <b>A</b>_<b>27</b> possessed appreciable curative bioactivities on TMV in vivo, with 50% effective concentration values ranging from 132.25 to 156.10 μg/mL. These values are superior to that of ningnanmycin (281.22 μg/mL) and suggest that novel 4­(3<i>H</i>)-quinazolinone derivatives containing 1,4-pentadien-3-one moiety can effectively control TMV. Evaluation of the antiviral properties in field studies and the mechanisms underlying the enhanced antiviral activities of these derivatives are an interesting topic for future investigation

Crystal Structure of a Four-Layer Aggregate of Engineered TMV CP Implies the Importance of Terminal Residues for Oligomer Assembly

<div><p>Background</p><p>Crystal structures of the tobacco mosaic virus (TMV) coat protein (CP) in its helical and disk conformations have previously been determined at the atomic level. For the helical structure, interactions of proteins and nucleic acids in the main chains were clearly observed; however, the conformation of residues at the C-terminus was flexible and disordered. For the four-layer aggregate disk structure, interactions of the main chain residues could only be observed through water–mediated hydrogen bonding with protein residues. In this study, the effects of the C-terminal peptides on the interactions of TMV CP were investigated by crystal structure determination.</p><p>Methodology/Principal Findings</p><p>The crystal structure of a genetically engineered TMV CP was resolved at 3.06 Å. For the genetically engineered TMV CP, a six-histidine (His) tag was introduced at the N-terminus, and the C-terminal residues 155 to 158 were truncated (N-His-TMV CP¹⁹). Overall, N-His-TMV CP¹⁹ protein self-assembled into the four-layer aggregate form. The conformations of residues Gln36, Thr59, Asp115 and Arg134 were carefully analyzed in the high radius and low radius regions of N-His-TMV CP¹⁹, which were found to be significantly different from those observed previously for the helical and four-layer aggregate forms. In addition, the aggregation of the N-His-TMV CP¹⁹ layers was found to primarily be mediated through direct hydrogen-bonding. Notably, this engineered protein also can package RNA effectively and assemble into an infectious virus particle.</p><p>Conclusion</p><p>The terminal sequence of amino acids influences the conformation and interactions of the four-layer aggregate. Direct protein–protein interactions are observed in the major overlap region when residues Gly155 to Thr158 at the C-terminus are truncated. This engineered TMV CP is reassembled by direct protein–protein interaction and maintains the normal function of the four-layer aggregate of TMV CP in the presence of RNA.</p></div

The inter-chain and intra-chain interaction model of N-His-TMV CP¹⁹ and the previously reported TMV CP disk (PDB code: 1EI7).

<p>(A) The inter-chain and intra-chain interaction model of N-His-TMV CP¹⁹. (B) The inter-chain and intra-chain interaction model of the previously reported TMV CP disk structure (PDB code: 1EI7).</p