17 research outputs found
Magnitude and dominance of resistance to Cry1Ac in <i>H. armigera</i> associated with cadherin resistance alleles: <i>r</i><sub>15</sub> in the cytoplasmic domain and <i>r</i><sub>1</sub> in the extracellular region.
a<p>Concentration killing 50% of larvae and 95% fiducial limits (µg Cry1Ac per cm<sup>2</sup> diet).</p>b<p>Resistance ratio = LC<sub>50</sub> of a strain or F<sub>1</sub> progeny from a cross divided by LC<sub>50</sub> of the susceptible SCD strain.</p>c<p>Survival at the diagnostic concentration (1 µg Cry1Ac per cm<sup>2</sup> diet), n = 48.</p>d<p><i>h</i> ranges from 0 for completely susceptible to 1 for completely dominant.</p>e<p><i>h</i> calculated from LC<sub>50</sub> values <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053418#pone.0053418-Liu1" target="_blank">[34]</a>.</p>f<p><i>h</i> calculated from survival at the diagnostic concentration <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053418#pone.0053418-Liu1" target="_blank">[34]</a>.</p>g<p><i>h</i> is calculated only for F<sub>1</sub> progeny from crosses between resistant and susceptible strains.</p>h<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053418#s2" target="_blank">Results</a> pooled from the two reciprocal crosses.</p
Genetic linkage between the cytoplasmic domain mutant of <i>HaCad</i> (<i>r</i><sub>15</sub>) and resistance to Cry1Ac in the XJ-r15 strain of <i>H. armigera</i>.
<p>We crossed a female (<i>ss</i>) from the susceptible SCD strain with a male from the resistant XJ-r15 strain (<i>r</i><sub>15</sub><i>r</i><sub>15</sub>) to produce the F<sub>1</sub> family (<i>r</i><sub>15</sub><i>s</i>). Next we crossed an F<sub>1</sub> male (<i>r</i><sub>15</sub><i>s</i>) with a susceptible SCD female (<i>ss</i>) to produce a backcross family from which larvae were placed on untreated diet (control) or diet treated with either 0.3 or 0.5 µg Cry1Ac per cm<sup>2</sup>. After 5 days, all survivors were transferred to untreated diet, reared to the final instar, and genotyped. The frequency of heterozygotes (<i>r</i><sub>15</sub><i>s</i>) relative to susceptible homozygotes (<i>ss</i>) was significantly higher for survivors on treated diet (68∶5) than for survivors on untreated diet (27∶23) (Fisher's exact test, P<0.0001).</p
Cry1Ac binding to Sf9 cells transfected with four alleles of <i>HaCad</i>.
<p><i>s</i>: susceptible allele. <i>r</i><sub>15</sub>: resistant allele, encoding cadherin with a 55 amino acid deletion in the cytoplasmic domain (C). <i>s</i>/<i>r</i><sub>15</sub>: chimeric allele with C from <i>r</i><sub>15</sub> and the other components from <i>s</i>. <i>r</i><sub>15</sub>/<i>s</i>: complementary chimeric allele with C from <i>s</i> and the other components from <i>r</i><sub>15</sub>. Cells were treated with 10 nM Cry1Ac, then probed sequentially with anti-Cry1Ac antiserum (1∶100) and FITC-conjugated anti-rabbit antibody (1∶100). No Cry1Ac binding was detected in control cells that were either transfected with an empty bacmid (EB) or not transfected (Sf9).</p
Non-Recessive Bt Toxin Resistance Conferred by an Intracellular Cadherin Mutation in Field-Selected Populations of Cotton Bollworm
<div><p>Transgenic crops producing <em>Bacillus thuringiensis</em> (Bt) toxins have been planted widely to control insect pests, yet evolution of resistance by the pests can reduce the benefits of this approach. Recessive mutations in the extracellular domain of toxin-binding cadherin proteins that confer resistance to Bt toxin Cry1Ac by disrupting toxin binding have been reported previously in three major lepidopteran pests, including the cotton bollworm, <em>Helicoverpa armigera</em>. Here we report a novel allele from cotton bollworm with a deletion in the intracellular domain of cadherin that is genetically linked with non-recessive resistance to Cry1Ac. We discovered this allele in each of three field-selected populations we screened from northern China where Bt cotton producing Cry1Ac has been grown intensively. We expressed four types of cadherin alleles in heterologous cell cultures: susceptible, resistant with the intracellular domain mutation, and two complementary chimeric alleles with and without the mutation. Cells transfected with each of the four cadherin alleles bound Cry1Ac and were killed by Cry1Ac. However, relative to cells transfected with either the susceptible allele or the chimeric allele lacking the intracellular domain mutation, cells transfected with the resistant allele or the chimeric allele containing the intracellular domain mutation were less susceptible to Cry1Ac. These results suggest that the intracellular domain of cadherin is involved in post-binding events that affect toxicity of Cry1Ac. This evidence is consistent with the vital role of the intracellular region of cadherin proposed by the cell signaling model of the mode of action of Bt toxins. Considered together with previously reported data, the results suggest that both pore formation and cell signaling pathways contribute to the efficacy of Bt toxins.</p> </div
Responses to Bt toxin Cry1Ac of <i>H. armigera</i> from a susceptible strain (SCD, blue), three resistant strains (red), and the F<sub>1</sub> progeny from crosses between each resistant strain and the susceptible strain (purple).
<p>SCD-r1: resistant strain with allele <i>r<sub>1</sub></i> affecting the extracellular domain of HaCad. XJ-r15 and AY-r15: resistant strains (from Xiajin and Anyang, respectively) with allele <i>r</i><sub>15</sub> affecting the cytoplasmic domain of HaCad. Resistance ratio is the concentration killing 50% of larvae (LC<sub>50</sub>) of each strain or group of F<sub>1</sub> progeny divided by the LC<sub>50</sub> for the susceptible SCD strain. The black bars show the 95% fiducial limits for LC<sub>50</sub>.</p
Cadherin protein of <i>H. armigera</i> encoded by <i>HaCad</i>.
<p><b>A.</b> Protein structure of HaCad predicted from cDNA with extracellular region (amino-terminal signal sequence [SIG], 11 cadherin repeats <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053418#pone.0053418-Mendelsohn1" target="_blank">[1]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053418#pone.0053418-VanRensburg1" target="_blank">[11]</a>, membrane proximal region [MPR]), transmembrane region (TM), and cytoplasmic domain (C). <b>B.</b> Genomic DNA sequence of <i>HaCad</i>. Resistance allele <i>r<sub>1</sub></i> has a stop codon at 428G in cadherin repeat 3 caused by a genomic DNA deletion of ca. 10 kb <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053418#pone.0053418-Yang2" target="_blank">[36]</a>. HaCad encoded by resistance allele <i>r</i><sub>15</sub> lacks 55 amino acids in the cytoplasmic domain caused by a 165 bp deletion in exon 32. We found three genomic DNA variants of <i>r</i><sub>15</sub> that cause loss of exon 32, one from each of three field populations: 1459 bp insertion from Xiajin, 92 bp deletion from Anyang, and >5000 bp insertion from Anci.</p
Mortality of Sf9 cells exposed to Cry1Ac.
<p>Sf9 cells were transfected with one of four alleles of <i>HaCad</i> (<i>s</i>, <i>r</i><sub>15</sub>, <i>r</i><sub>15</sub><i>/s</i>, and <i>s/r</i><sub>15</sub>; see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053418#pone-0053418-g004" target="_blank">Figures 4</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053418#pone.0053418.s002" target="_blank">S2</a> for details) or an empty bacmid (EB), or were not transfected (NT). For cells transfected with alleles of <i>HaCad</i>, LC<sub>50</sub> values (95% FL) were significantly higher for alleles with the cytoplasmic domain of <i>r</i><sub>15</sub> (<i>r</i><sub>15</sub>: 85 [71–110] and <i>s/r</i><sub>15</sub>: 82 [68–100]) than for alleles with the cytoplasmic domain of <i>s</i> (<i>s</i>: 38 [31–46] or <i>r</i><sub>15</sub><i>/s</i>: 38 [31–45]). LC<sub>50</sub> values did not differ significantly between Sf9 cells transfected with alleles of <i>HaCad</i> that had the same cytoplasmic domain (<i>r</i><sub>15</sub> and <i>s/r</i><sub>15</sub>; <i>s</i> and <i>r</i><sub>15</sub><i>/s</i>).</p
Ultrafast Self-Healing Nanocomposites via Infrared Laser and Their Application in Flexible Electronics
The continuous evolution
toward flexible electronics with mechanical robust property and restoring
structure simultaneously places high demand on a set of polymeric
material substrate. Herein, we describe a composite material composed
of a polyurethane based on Diels–Alder chemistry (PU-DA) covalently
linked with functionalized graphene nanosheets (FGNS), which shows
mechanical robust and infrared (IR) laser self-healing properties
at ambient conditions and is therefore suitable for flexible substrate
applications. The mechanical strength can be tuned by varying the
amount of FGNS and breaking strength can reach as high as 36 MPa with
only 0.5 wt % FGNS loading. On rupture, the initial mechanical properties
are restored with more than 96% healing efficiency after 1 min irradiation
time by 980 nm IR laser. Especially, this is the highest value of
healing efficiency reported in the self-healable materials based on
DA chemistry systems until now, and the composite exhibits a high
volume resistivity up to 5.6 × 10<sup>11</sup> Ω·cm
even the loading of FGNS increased to 1.0 wt %. Moreover, the conductivity
of the broken electric circuit which was fabricated by silver paste
drop-cast on the healable composite substrate was completely recovered
via IR laser irradiating bottom substrate mimicking human skin. These
results demonstrate that the FGNS-PU-DA nanocomposite can be used
as self-healing flexible substrate for the next generation of intelligent
flexible electronics
DYRK2 Negatively Regulates Type I Interferon Induction by Promoting TBK1 Degradation via Ser527 Phosphorylation
<div><p>Viral infection activates the transcription factors NF-κB and IRF3, which contribute to the induction of type I interferons (IFNs) and cellular antiviral responses. Protein kinases play a critical role in various signaling pathways by phosphorylating their substrates. Here, we identified dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 2 (DYRK2) as a negative regulator of virus-triggered type I IFN induction. DYRK2 inhibited the virus-triggered induction of type I IFNs and promoted the K48-linked ubiquitination and degradation of TANK-binding kinase 1 (TBK1) in a kinase-activity-dependent manner. We further found that DYRK2 phosphorylated Ser527 of TBK1, which is essential for the recruitment of NLRP4 and for the E3 ubiquitin ligase DTX4 to degrade TBK1. These findings suggest that DYRK2 negatively regulates virus-triggered signaling by targeting TBK1 for phosphorylation and priming it for degradation, and these data provide new insights into the molecular mechanisms that dictate the cellular antiviral response.</p></div
DYRK2 promoted TBK1 degradation via K48-linked ubiquitination.
<p>(A) Overexpression of DYRK2 induced TBK1 degradation in a dose-dependent manner. The 293T cells (2×10<sup>5</sup>) were transfected with the Flag-TBK1, HA-β-actin and HA-DYRK2 plasmids (0.1, 0.2 or 0.4 μg) and were treated with dimethyl sulfoxide (DMSO) or MG132. The cells were lysed, and the lysates were analyzed by immunoblotting with anti-Flag or anti-HA antibodies. (B) Overexpression of wild-type DYRK2 but not mutant DYRK2, promoted the ubiquitination of TBK1. The 293 cells (1×10<sup>7</sup>) were transfected with the indicated plasmids. Twenty-four hours after transfection, cell lysates were immunoprecipitated with an anti-TBK1 antibody. The immunoprecipitates were analyzed by immunoblotting with an anti-Myc antibody (upper). Protein expression was analyzed by immunoblotting with the indicated antibodies (lower). (C) Effects of DYRK2 RNAi on the SeV-induced ubiquitination of endogenous TBK1. The 293 cells (5×10<sup>7</sup>) were transfected with control or DYRK2 RNAi (#2) plasmids. Twenty hours after transfection, the cells were infected or not infected with SeV for 10 h. The cell lysates were immunoprecipitated with an anti-TBK1 antibody. The immunoprecipitates were analyzed by immunoblotting with an anti-ubiquitin antibody (top). The expressions of related proteins were examined by immunoblotting with the indicated antibodies (bottom). (D) DYRK2 promoted K48-linked but not K63-linked ubiquitination of TBK1. The 293 cells (2×10<sup>6</sup>) were transfected with HA-tagged Lys-48-only or Lys-63-only ubiquitin plasmids and the other indicated plasmids. Twenty-four hours after transfection, cell lysates were immunoprecipitated with an anti-TBK1 antibody and then analyzed by immunoblotting with an anti-HA antibody (upper panel). The expressions of related proteins were examined by immunoblotting with the indicated antibodies (lower panel).</p