Cloning, ligand-binding, and temporal expression of ecdysteroid receptors in the diamondback moth, Plutella xylostella

BACKGROUND: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a devastating pest of cruciferous crops worldwide, and has developed resistance to a wide range of insecticides, including diacylhydrazine-based ecdysone agonists, a highly selective group of molt-accelerating biopesticides targeting the ecdysone receptors. RESULT: In this study, we cloned and characterized the ecdysone receptors from P. xylostella, including the two isoforms of EcR and a USP. Sequence comparison and phylogenetic analysis showed striking conservations among insect ecdysone receptors, especially between P. xylostella and other lepidopterans. The binding affinity of ecdysteroids to in vitro-translated receptor proteins indicated that PxEcRB isoform bound specifically to ponasterone A, and the binding affinity was enhanced by co-incubation with PxUSP (Kd =3.0±1.7 nM). In contrast, PxEcRA did not bind to ponasterone A, even in the presence of PxUSP. The expression of PxEcRB were consistently higher than that of PxEcRA across each and every developmental stage, while the pattern of PxUSP expression is more or less ubiquitous. CONCLUSIONS: Target site insensitivity, in which the altered binding of insecticides (ecdysone agonists) to their targets (ecdysone receptors) leads to an adaptive response (resistance), is one of the underlying mechanisms of diacylhydrazine resistance. Given the distinct differences at expression level and the ligand-binding capacity, we hypothesis that PxEcRB is the ecdysone receptor that controls the remodeling events during metamorphosis. More importantly, PxEcRB is the potential target site which is modified in the ecdysone agonist-resistant P. xylostella

Mosquito cell line C6/36 shows resistance to Cyt1Aa6

265-269This study aimed to investigate the resistance mechanism of C6/36 cells to Cyt1Aa6 protein under selection pressure. Receptor binding properties of Cyt1Aa6 toward sensitive and resistant C6/36 cells were investigated. More sensitive cells were detected with goat-anti-rabbit-FITC-labeled antibody, and the quantity of in vitro activated Cyt1Aa6 toxin bound to resistant cells was greatly reduced. Ligand western blot assays showed that disappearance of the 26 kDa protein and weakness of the positive bands of 68 kDa from resistant cells might lead to the resistance of C6/36 cells to Cyt1Aa6 toxin. The resistance of C6/36 cells was detected under selection in vitro-activated Cyt1Aa6 toxin. Receptor binding demonstrated that reduced Cyt1Aa6 bound to resistant cells, which might be closely related to the disappearance and weakness of some proteins. The results presented here are the first to demonstrate that Cyt1Aa protein, a uniquely characteristic toxin, induced resistance at the cellular level. It might be attributed to the change of receptors

Cardiorenal syndrome in incident peritoneal dialysis patients: What is its effect on patients' outcomes?

BackgroundPeritoneal dialysis (PD) is increasingly used for long-term management of Cardiorenal Syndrome (CRS). We compared outcomes in incident PD patients according to their baseline heart failure status.MethodsThis retrospective cohort study evaluated all-cause and cardiovascular mortality in incident PD patients with different heart failure status (non-CRS, acute heart failure [AHF], type II CRS, type IV CRS) who started PD between 2006 and 2016 in the Peking University Third Hospital.ResultsOf 748 patients included in the study, there were 466 (62.3%), 214 (28.6%), 27 (3.6%), and 41 (5.5%) patients in the non-CRS, AHF, type II CRS and type IV CRS groups, respectively. Patients with CRS were older (pConclusionIncident PD patients with different types of CRS had higher rates of both all-cause and cardiovascular mortality compared with patients without CRS. However, these observed adverse outcomes may be related to associated older age and higher prevalence of comorbidities, rather than CRS per se, except for type IV CRS, treatment strategies to reduce high cardiovascular CVD mortality may needed

E-value and species distributions of the top BLASTx hits.

<p>The BLASTx search was performed against NCBI non-redundant protein database with an E-value cut-off of 10⁻⁵. A: E-value distribution. B: Species distribution.</p

Length distribution of unigenes in assembled <i>Octodonta nipae</i> transcriptome.

<p><i>De novo</i> assembly produced 49,919 unigenes beteween 100 and 2000 bp in length. The x and y-axes represent the length of unigenes and the number of unigenes in a corresponding length, respectively.</p

Transcriptome Immune Analysis of the Invasive Beetle <i>Octodonta nipae</i> (Maulik) (Coleoptera: Chrysomelidae) Parasitized by <i>Tetrastichus brontispae</i> Ferrière (Hymenoptera: Eulophidae)

<div><p>The beetle <i>Octodonta nipae</i> (Maulik) (Coleoptera: Chrysomelidae) is a serious invasive insect pest of palm plants in southern China, and the endoparasitoid <i>Tetrastichus brontispae</i> Ferrière (Hymenoptera: Eulophidae) is a natural enemy of this pest that exhibits great ability in the biocontrol of <i>O. nipae</i>. For successful parasitism, endoparasitoids often introduce or secrete various virulence factors to suppress host immunity. To investigate the effects of parasitization by <i>T. brontispae</i> on the <i>O. nipae</i> immune system, the transcriptome of <i>O. nipae</i> pupae was analyzed with a focus on immune-related genes through Illumina sequencing. <i>De novo</i> assembly generated 49,919 unigenes with a mean length of 598 bp. Of these genes, 27,490 unigenes (55.1% of all unigenes) exhibited clear homology to known genes in the NCBI nr database. Parasitization had significant effects on the transcriptome profile of <i>O. nipae</i> pupae, and most of these differentially expressed genes were down-regulated. Importantly, the expression profiles of immune-related genes were significantly regulated after parasitization. Taken together, these transcriptome sequencing efforts shed valuable light on the host (<i>O. nipae</i>) manipulation mechanisms induced by <i>T. brontispae</i>, which will pave the way for the development of novel immune defense-based management strategies of <i>O. nipae</i>, and provide a springboard for further molecular analyses, particularly of <i>O. nipae</i> invasion.</p></div

The Cellular Immunological Responses and Developmental Differences between Two Hosts Parasitized by Asecodes hispinarum

This study aims to investigate the developmental interactions of Asecodes hispinarum Bou&#269;ek on Brontispa longissima Gestro and Octodonta nipae Maulik, as well as the cellular immune responses of B. longissima and O. nipae larvae in response to parasitism by A. hispinarum, with the hope of determining the reason for the difference in larval breeding of A. hispinarum in B. longissima and O. nipae. The effects of parasitism by A. hispinarum on the larval development, hemocyte count, and proportion of the hemocyte composition of the two hosts were carried out through selective assay and non-selective assay using statistical analysis and anatomical imaging. There was no significant difference in parasitic selection for A. hispinarum on the larvae of these two beetles; however, more eggs were laid to B. longissima larvae than to O. nipae larvae after parasitism by A. hispinarum. The eggs of A. hispinarum were able to grow and develop normally inside the larvae of B. longissima, and the parasitism caused the larvae of B. longissima become rigid within 7 d, with a high larval mortality rate of 98.88%. In contrast, the eggs of A. hispinarum were not able to develop normally inside the O. nipae larvae, with a high encapsulation rate of 99.05%. In addition, the parasitism by A. hispinarum caused a 15.31% mortality rate in O. nipae larvae and prolonged the larval stage by 5 d and the pupal stage by 1 d. The number of hemocytes during the 12, 24, 48, 72, and 96 h of the four instars from O. nipae larvae was 6.08 times higher than from B. longissima larvae of the same age. After 24 h of being parasitized by A. hispinarum, the total number of hemocytes and granulocyte proportion of B. longissima larvae increased significantly. However, the total number of hemocytes and plasmatocyte proportion of O. nipae increased significantly after 24, 72, and 96 h, and the proportion of granulocytes increased significantly after 12 h post-parasitism. The results in the present study indicated that A. hispinarum was unable to successfully reproduce offspring in O. nipae, but its spawning behavior had an adverse effect on the larval development of its host. In addition, the adequate number of hemocytes and more pronounced changes in the hemocyte count and hemocyte composition ratio in the larvae after parasitization may be important factors for the successful encapsulation in O. nipae larvae

qRT-PCR validation of ten selected genes in <i>Octodonta nipae</i> pupae which showed differential expression after parasitization by <i>Tetrastichus brontispae</i> on the basis of Illumina sequencing analysis.

<p>The relative expression levels of these unigenes were transformed into the log₂Ratio of parasitized (P) to non-parasitized (NP). The error bars indicate standard deviations of the mean from three independent replications.</p

Illumina sequencing and assembly summary of the <i>Octodonta nipae</i> transcriptome.

<p>*Q20 percentage: Percentage of nucleotide error rate under 0.01.</p><p>**N: Uncertain base in the output sequencing data.</p><p>***N50: Median length of all contigs or unigenes.</p

Immune-related genes differentially transcribed in <i>Octodonta nipae</i> pupae following parasitization by <i>Tetrastichus brontispae</i>.

<p>*Fold change was calculated as log₂ P/NP. P: parasitized. NP: non-parasitized.</p><p>**FDR: False discovery rate.</p><p>Differentially expressed genes were identified on the basis of FDR≤0.001 and the absolute value of log₂ P/NP≥1.</p