28 research outputs found

    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

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    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

    Semisynthesis of Esters of Fraxinellone C4/10-Oxime and Their Pesticidal Activities

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    A total of 20 esters of fraxinellone C4/10-oxime were synthesized and determined by melting points, optical rotation, infrared spectra, proton nuclear magnetic resonance spectra, and high-resolution mass spectrometry spectra. Two steric configurations of compounds <b>7i</b> and <b>8i</b> were unambiguously confirmed by X-ray crystallography. Additionally, their pesticidal activities were assessed on two typical lepidopteran pests, Mythimna separata Walker and Plutella xylostella Linnaeus. Generally, all compounds exhibited less potent oral toxicity than toosendanin against third-instar larvae of P. xylostella. However, all compounds showed the growth inhibitory property against early third-instar larvae of M. separata. Notably, compounds <b>7m</b>, <b>8b</b>, <b>8k</b>, <b>9</b>, and <b>11</b> displayed more potent pesticidal activity than toosendanin. This demonstrated that introducing the C-4 carbonyl or oxime group on fraxinellone resulted in more promising derivatives than those bearing a C-10 carbonyl or oxime substituent

    Localized Imaging of Programmed Death-Ligand 1 on Individual Tumor-Derived Extracellular Vesicles for Prediction of Immunotherapy Response

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    Programmed death-ligand 1 (PD-L1) on tumor-derived small extracellular vesicles (EVs) is a biomarker for prediction of the immunotherapy response. However, conventional bulk measurement can hardly analyze the expression of PD-L1 on individual tumor-derived EVs. Herein, a method for localized imaging of tumor-derived individual EVs PD-L1 (LITIE) is developed. In this assay, EVs in plasma were directly captured on a biochip. Then the liposome-mediated membrane fusion strategy was used to image miR-21 in EVs to discriminate miR-21-positive EVs from the whole EVs populations. Subsequently, the primer exchange reaction (PER) is applied to generate localized and amplified fluorescent signals for imaging PD-L1 on identified tumor-derived EVs. When applied in clinical sample tests, the LITIE assay could effectively distinguish breast cancer patients from healthy donors or patients with benign tumors. Interestingly, in a mice melanoma model, the LITIE assay showed the ability to predict immunotherapy response even before drug treatment. Thus, we think the strategy of measuring individual tumor-derived EVs PD-L1 could serve as an alternative way for screening clinical responders suitable for immunotherapy

    The relative gene expression of <i>LsLysozyme</i> among larvae reared at densities of 1, 10 and 30 larvae per jar and before and after treatment with <i>B</i>. <i>bassiana</i> are shown in A and B, respectively.

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    <p>The relative gene expression of <i>LsLysozyme</i> in fifth-instar larvae infected with <i>B</i>. <i>bassiana</i> is shown in C. Data are presented as the mean±SE, n = 3. Different characters denote significant difference at P < 0.01.</p

    Efficient Production of (<i>R</i>)-2-Hydroxy-4-Phenylbutyric Acid by Using a Coupled Reconstructed d-Lactate Dehydrogenase and Formate Dehydrogenase System

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    <div><p>Background</p><p>(<i>R</i>)-2-Hydroxy-4-phenylbutyric acid [(<i>R</i>)-HPBA] is a key precursor for the production of angiotensin-converting enzyme inhibitors. However, the product yield and concentration of reported (<i>R</i>)-HPBA synthetic processes remain unsatisfactory.</p><p>Methodology/Principal Findings</p><p>The Y52L/F299Y mutant of NAD-dependent d-lactate dehydrogenase (d-nLDH) in <i>Lactobacillus bulgaricus</i> ATCC 11842 was found to have high bio-reduction activity toward 2-oxo-4-phenylbutyric acid (OPBA). The mutant d-nLDH<sup>Y52L/F299Y</sup> was then coexpressed with formate dehydrogenase in <i>Escherichia coli</i> BL21 (DE3) to construct a novel biocatalyst <i>E. coli</i> DF. Thus, a novel bio-reduction process utilizing whole cells of <i>E. coli</i> DF as the biocatalyst and formate as the co-substrate for cofactor regeneration was developed for the production of (<i>R</i>)-HPBA from OPBA. The biocatalysis conditions were then optimized.</p><p>Conclusions/Significance</p><p>Under the optimum conditions, 73.4 mM OPBA was reduced to 71.8 mM (<i>R</i>)-HPBA in 90 min. Given its high product enantiomeric excess (>99%) and productivity (47.9 mM h<sup>−1</sup>), the constructed coupling biocatalysis system is a promising alternative for (<i>R</i>)-HPBA production.</p></div

    Highly Effective Detection of Exosomal miRNAs in Plasma Using Liposome-Mediated Transfection CRISPR/Cas13a

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    Exosomal miRNAs play a critical role in cancer biology and could be potential biomarkers for cancer diagnosis. However, due to the low abundance of miRNAs in the exosomes, recognizing and detecting disease-associated exosomal miRNAs in an easy-to-operate way remain a challenge. Herein, we used a liposome-mediated membrane fusion strategy (MFS) to transfect CRISPR/Cas13a into exosomes, termed MFS-CRISPR, directly measuring exosomal miRNAs in plasma. Using the MFS-CRISPR platform for detection of the exosomal miR-21, we achieve a linear range spanning four orders of magnitude (104–108 particles/mL) and the method is able to detect the exosomal miR-21 in as low as 1.2 × 103 particles/mL. The liposome-mediated MFS could confine fluorescent signals in fused vesicles, which can be used for exosome heterogeneity analysis. Moreover, MFS-CRISPR assay was evaluated by measuring clinical samples, and the difference of miR-21 expression of breast cancer patients and healthy donors was significant. Because of high sensitivity and simplicity, the proposed method could have promising clinical potential for cancer diagnosis and treatment monitoring

    DataSheet1_Study on the degradation and metabolic mechanism of four quinolone antibiotics by mixed strains.PDF

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    Quinolone antibiotics are a common class of antibiotics in the environment and have received considerable attention. In this study, three groups of mixed degradation strains targeting mixed quinolone antibiotics, norfloxacin (NOR), and enrofloxacin (ENR) were selected through screening, enrichment, and microbial diversity detection experiments. The strains screened in this study are divided into two categories through degradation efficiency experiments, community composition detection and functional enrichment analysis. In groups mix and ENR, the resistant bacteria are the main microorganisms and the degrading bacteria are the secondary ones, while in group NOR, the strains with degradation effects are the main ones, and the strains with resistance effects are the secondary ones. What’s more, that carbon sources have little effect on the community composition of the quinolone antibiotic degrading and tolerant bacteria, the difference between groups is mainly controlled by the type of antibiotics. On this basis, we found the key to NOR degradation is the cleavage of carbon nitrogen bonds on the piperazine ring, followed by oxygenation and deethylation. Preliminary studies have confirmed that the optimal degradation conditions for NOR degrading strains, and also found that environmental factors did not significantly affect the degradation efficiency of the Mix and NOR degrading strains, which indicating that the mixed bacteria can degrade NOR in different real environments effectively such as tap water, seawater, river water, and lake water. This manuscript is the first report on a mixed strain of quinolone antibiotic microbial degradation, and it is also the study with the highest NOR degradation efficiency among known reports. It has great research value for the co-metabolism and biodegradation of quinolone antibiotics in the environment.</p

    Expression patterns of <i>LsLysozyme</i> during life stages and in different tissues.

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    <p>The expression profiles of <i>LsLysozyme</i> during developmental stages are depicted in (A). L1-L5, 1st to 5th-instar larvae. The tissue expression distribution of <i>LsLysozyme</i> is shown in (B). Data are shown as the mean ± SE, n = 3. Different letters indicate significant difference at P < 0.01.</p

    Uniform Ultrasmall Graphene Oxide Nanosheets with Low Cytotoxicity and High Cellular Uptake

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    Graphene oxide (GO) is an increasingly important nanomaterial, which exhibits great promise in the area of bionanotechnology and nanobiomedicine. In this study, we synthesized uniform ultrasmall graphene oxide nanosheets with high yield by a convenient way of modified Hummers’ method. The uniform ultrasmall GO nanosheets, which exhibit fluorescence property and outstanding stability in a wide range of pH values, were less than 50 nm. Furthermore, because of the advantages of its lateral size, the uniform ultrasmall GO nanosheets showed excellent biocompatibility of lower cytotoxicity and higher cellular uptake amount compared to the random large GO nanosheets. Therefore, the as-prepared uniform ultrasmall GO nanosheets could be explored as the ideal nanocarriers for drug delivery and intracellular fluorescent nanoprobe
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