Myzus persicae (Sulzer) is one of the most serious agricultural pests in China, and management strategies mainly rely on insecticidal treatment. To evaluate the resistance of field populations of M. ...persicae to seven insecticides, we assessed the susceptibility of 11 field populations collected from eight provinces in China using leaf-dip bioassays. Toxicity assays showed that M. persicae field populations have developed several levels of resistance to each tested insecticide. For pyrethroids, the field populations have developed a high level of resistance to β-cypermethrin and cypermethrin, while the resistance to bifenthrin is still low. The resistance ratios of field populations to imidacloprid ranged from 1.48 to 52.36, and eight populations have developed moderate to high resistance. Resistance to acetamiprid is low, and only two populations have a moderate level of resistance. Most of the field populations of M. persicae developed moderate to high resistance to methomyl and omethoate. To investigate potential resistance mechanisms, we analyzed the enzyme activity of carboxylesterases, the type of amplified esterase genes, as well as the kdr (L1014F) mutation. All of the field populations exhibited a higher esterase activity compared to the laboratory susceptible strain. An amplified FE4, as well as the L1014F mutation, were also found in all of our experimental field populations. These results provide valuable insight into the current status of insecticide resistance and will prove to be a valuable resource in designing appropriate resistance management strategies for M. persicae in China.
Display omitted
•Multiple levels of resistance to insecticides were initially observed in the field populations of Myzus persicae in China.•These populations possessed elevated carboxylesterase activities conferring moderate to high resistance to omethoate.•FE4 gene amplification confers field population resistance to omethoate, methomyl, β-cypermethrin and cypermethrin.•Pyrethroid resistance is widespread across China by the presence of kdr mutation only in heterozygous genotype.
Aim
Coregonus peled fillets were used as a model to evaluate the dominant bacterial growth of chilled fish during storage after shipping and interactions of selected bacterial strains.
Methods and ...Results
Coregonus peled fillets were transported by air and land in ice boxes about 48 h from aquatic products company in Xinjiang, China, to the laboratory located in Dalian, China. Both culture‐dependent (plate counts on nonselective media) based on 16S rRNA gene sequencing and culture‐independent (Illumina‐MiSeq high‐throughput sequencing) methods were used. To detect interactions among bacterial populations from chilled fish, the influence of 18 test strains on the growth of 12 indicator isolates was measured by a drop assay and in liquid culture medium broth. The results showed that bacterial counts exceeded 7.0 log CFU/g following storage for 4 days at 4 °C. When the bacterial counts exceeded 8.5 log CFU/g after 12 days, the predominant micro‐organisms were Aeromonas, Pseudomonas, Carnobacterium, Psychrobacter and Shewanella, as measured by the culture‐independent method. All test strains showed inhibiting effects on the growth of other strains in liquid culture. Pseudomonas isolates showed antibacterial activity for approximately 60% of the indicator strains on nutritional agar plates. The majority of test isolates enhancing indicator strain growth were the strains isolated on day 0.
Conclusions
High‐throughput sequencing approach gives whole picture of bacterial communities in chilled C. peled fillets during storage, while growth interferences between selected bacterial strains illustrate the complexity of microbial interactions.
Significance and Impact of the Study
We determined the bacterial communities and growth interferences in chilled Coregonus peled after shipping and these are the first data concerning microbiota in C. peled using a culture‐independent analysis. The present study will be useful for manufacture and preservation of C. peled products by providing with valuable information regarding microbiological spoilage of C. peled.
Matrix metalloproteinase-2 (MMP-2), also known as gelatinase A, is involved in vascular calcification. Another member of gelatinases is MMP-9 (gelatinase B). However, the role of gelatinases in the ...pathogenesis of vascular calcification is not well understood. The current study aims to clarify the relationship between gelatinases and vascular calcification and to elucidate the underlying mechanism. Beta-glycerophosphate (β-GP) was used to induce calcification of vascular smooth muscle cells (VSMCs) with or without 2-(4-Phenoxyphenyl)sulfonylmethyl-thiirane (SB-3CT), a specific gelatinases inhibitor. Levels of calcification were determined by assessing calcium content and calcification area of VSMCs. Phenotype transition of VSMCs was observed by assessing expressions of alkaline phosphatase (ALP), smooth muscle α-actin (SM-α-actin) and desmin. Gelatin zymography was applied to determine the activities of gelatinases, and western blot was applied to determine expressions of gelatinases, bone morphogenetic protein-2 (BMP-2), Runt-related transcription factor 2 (RUNX2) and msh homeobox homolog 2 (Msx-2). Gelatinases inhibition by SB-3CT alleviated calcification and phenotype transition of VSMCs induced by β-GP. Increased gelatinases expression and active MMP-2 were observed in calcifying VSMCs. Gelatinases inhibition reduced expression of RUNX2, Msx-2 and BMP-2. BMP-2 treatment increased expressions of RUNX2 and Msx-2, while noggin, an antagonist of BMP-2, decreased expressions of RUNX2 and Msx-2. Gelatinases promote vascular calcification by upregulating BMP-2 which induces expression of RUNX2 and Msx-2, two proteins associated with phenotype transition of VSMCs in vascular calcification. Interventions targeting gelatinases inhibition might be a proper candidate for ameliorating vascular calcification.
•Gelatinases inhibition reduced calcification of cultured VSMCs.•Gelatinases inhibition attenuated phenotype transition of cultured VSMCs.•Gelatinases inhibition reduces calcification of VSMCs by down-regulating BMP-2.•Gelatinases are potential targets for treatment of vascular calcification.
The future trend in achieving precision medicine involves the development of non-invasive cancer biomarker sensors that offer high accuracy, low cost, and time-saving benefits for risk clarification, ...early detection, disease detection, and therapeutic monitoring. A facile approach for the synthesis of MoO3 nanosheets was developed by thermally oxidizing MoS2 nanosheets in air followed by thermal annealing. Subsequently, Au@MnO2 nanocomposites were prepared using a combined hydrothermal process and in situ chemical synthesis. In this study, we present a novel immunosensor design strategy involving the immobilization of antiHSP70 antibodies on Au@MnO2/MoO3 nanocomposites modified on a screen-printed electrode (SPE) using EDC/NHS chemistry. This study establishes HSP70 as a potential biomarker for monitoring therapeutic response during anticancer therapy. Impedance measurements of HSP70 on the Au@MnO2/MoO3/SPE immunosensor using EIS showed an increase in impedance with an increase in HSP70 concentration. The electrochemical immunosensor demonstrated a good linear response in the range of 0.001 to 1000 ng mL−1 with a detection limit of 0.17 pg mL−1 under optimal conditions. Moreover, the immunosensor was effective in detecting HSP70 at low concentrations in a lung adenocarcinoma cell line following Paclitaxel treatment, indicating its potential for early detection of the HSP70 biomarker in organ-on-a-chip and clinical applications.
Lung cancer is the leading cause of cancer-related death around the world. The circulating tumor DNA (ctDNA) of EGFR L858R in plasma is crucial for development, targeted drug therapy, and prognosis ...of non-small cell lung cancer, the main type of lung cancer. Accurately detecting ctDNA using conventional methods is challenging due to its characteristics, such as considerably short size, extremely low level, and short half-life. Thus, developing a rapid, accurate, and cost-effective method for ctDNA EGFR L858R detection is urgently needed. Herein, we developed an electrochemical biosensor of ctDNA EGFR L858R based on the CRISPR/Cas12a system and MB/Fe3O4@COF/PdAu nanocomposites. The CRISPR/Cas12a system played roles in the precise recognition of ctDNA targets and indistinguishable cleavage of single-stranded DNA. Additionally, the MB/Fe3O4@COF/PdAu nanocomposite has good catalytic activity and signal amplification performance. The proposed electrochemical biosensor showed high specificity, stability, and selectivity. Notably, the limit of detection of the proposed biosensor was 3.3 aM. The detection results of 25 clinical samples showed that 22 and 20 positive samples were detected by electrochemical detection and droplet digital polymerase chain reaction, respectively. Therefore, we established a high-precision, reliable, and convenient method for ctDNA detection, which has a potential application in the diagnosis and prognosis of cancer.
Display omitted
•Electrochemical sensor for ctDNA mutation of lung cancer was developed based on CRISPR/Cas12a.•CRISPR/Cas12a system played key roles in the precise recognition of target ctDNA.•The signal of biosensor was amplified by the good catalytic activity of Fe3O4@COF/PdAu nanocomposite.•The proposed biosensor showed high specificity, stability, and selectivity.
The nervous system is the part of our body that plays critical roles in the coordination of actions and sensory information as well as communication between different body parts through electrical ...signal transmissions. Current studies have shown that patients are likely to experience a functional loss if they have to go through a nerve repair for >15 mm lesion. The ideal treatment methodology is autologous nerve transplant, but numerous problems lie in this treatment method, such as lack of harvesting sites. Therefore, researchers are attempting to fabricate alternatives for nerve regeneration, and nerve conduit is one of the potential alternatives for nerve regeneration. In this study, we fabricated polyurethane/polydopamine/extracellular matrix (PU/PDA/ECM) nerve conduits using digital light processing (DLP) technology and assessed for its physical properties, biodegradability, cytocompatibility, neural related growth factor, and proteins secretion and expression and its potential in allowing cellular adhesion and proliferation. It was reported that PU/PDA/ECM nerve conduits were more hydrophilic and allowed enhanced cellular adhesion, proliferation, expression, and secretion of neural-related proteins (collagen I and laminin) and also enhanced expression of neurogenic proteins, such as nestin and microtubule-associated protein 2 (MAP2). In addition, PU/PDA/ECM nerve conduits were reported to be non-cytotoxic, had sustained biodegradability, and had similar physical characteristics as PU conduits. Therefore, we believed that PU/PDA/ECM nerve conduits could be a potential candidate for future nerve-related research or clinical applications.
Although autologous nerve grafting remains the gold standard treatment for peripheral nerve injuries, alternative methods such as development of nerve guidance conduits have since emerged and evolved ...to counter the many disadvantages of nerve grafting. However, the efficacy and viability of current nerve conduits remain unclear in clinical trials. Here, we focused on a novel decellularized extracellular matrix (dECM) and polydopamine (PDA)-coated 3D-printed poly(ε-caprolactone) (PCL)-based conduits, whereby the PDA surface modification acts as an attachment platform for further dECM attachment. We demonstrated that dECM/PDA-coated PCL conduits possessed higher mechanical properties when compared to human or animal nerves. Such modifications were proved to affect cell behaviors. Cellular behaviors and neuronal differentiation of Schwann cells were assessed to determine for the efficacies of the conduits. There were some cell-specific neuronal markers, such as Nestin, neuron-specific class III beta-tubulin (TUJ-1), and microtubule-associated protein 2 (MAP2) analyzed by enzyme-linked immunosorbent assay, and Nestin expressions were found to be 0.65-fold up-regulated, while TUJ1 expressions were 2.3-fold up-regulated and MAP2 expressions were 2.5-fold up-regulated when compared to Ctl. The methodology of PDA coating employed in this study can be used as a simple model to immobilize dECM onto PCL conduits, and the results showed that dECM/PDA-coated PCL conduits can as a practical and clinically viable tool for promoting regenerative outcomes in larger peripheral nerve defects.
The CRISPR/dCas9 system is a powerful tool to activate the transcription of target genes in eukaryotic or prokaryotic cells, but lacks assays in complex conditions, such as the biosynthesis of ...secondary metabolites.
In this study, to improve the transcription of the heterologously expressed biosynthetic genes for the production of epothilones, we established the CRISPR/dCas9-mediated activation technique in Myxococcus xanthus and analyzed some key factors involving in the CRISPR/dCas9 activation. We firstly optimized the cas9 codon to fit the M. xanthus cells, mutated the gene to inactivate the nuclease activity, and constructed the dCas9-activator system in an epothilone producer. We compared the improvement efficiency of different sgRNAs on the production of epothilones and the expression of the biosynthetic genes. We also compared the improvement effects of different activator proteins, the ω and α subunits of RNA polymerase, and the sigma factors σ54 and CarQ. By using a copper-inducible promoter, we determined that higher expressions of dCas9-activator improved the activation effects.
Our results showed that the CRISPR/dCas-mediated transcription activation is a simple and broadly applicable technique to improve the transcriptional efficiency for the production of secondary metabolites in microorganisms. This is the first time to construct the CRISPR/dCas9 activation system in myxobacteria and the first time to assay the CRISPR/dCas9 activations for the biosynthesis of microbial secondary metabolites.
Display omitted
•Electrospun fibrous PES MMMs were prepared for hemoperfusion, to which fine adsorbent particles were added.•In contrast to adsorbent and PES membrane alone, synergistic adsorption of ...creatinine and p-cresol was observed using the MMMs.•The strongest synergism occurred for creatinine adsorption using zeolite-incorporated MMMs, with a synergism factor of 3.23.•Operating stability of the MMMs was satisfactory by checking their adsorption ability before and after they were sonicated (deviation < 1 %).•Hemolysis and viability MTT tests verified the hemo- and biocompatibility of the as-fabricated PES-based MMMs.
In this study, fibrous polyethersulfone (PES) mixed-matrix membranes were prepared by electrospinning, to which fine adsorbents including two zeolites, activated carbon, and graphene oxide were added. They were applied as a hemoperfusion unit for efficient clearance of creatinine and p-cresol from simulated serum. Physicochemical and morphological properties of the prepared fibrous membranes were firstly investigated. Batch adsorption tests revealed that the equilibria of uremic toxins on all fibrous membranes were attained within 4 h. The adsorption isotherms of creatinine and p-cresol in simulated serum (37 °C and pH 7.4), with and without 30 g/L of BSA, could be better described by the Langmuir equation, compared to the Freundlich equation. In contrast to pure adsorbent and PES membrane alone, synergistic adsorption (defined in equation (7) in the text) of creatinine and p-cresol using the fabricated mixed-matrix membranes was observed. In particular, the strongest synergism occurred in creatinine adsorption using the zeolite-incorporated PES membranes, mainly due to the comparable dimensions of the fibers and zeolite particles. The operating stability of as-prepared fibrous membranes was assessed by checking their adsorption ability before and after they were sonicated. The hemolysis tests and viability measurements of human umbilical vein endothelial cells finally indicated that the prepared PES-based mixed matrix membranes were hemo- and bio-compatible.
In our previous study, we found that gelatin-based materials exhibit good conductivity and are non-cytotoxic. In this study, gelatin was cross-linked with bisvinyl sulfonemethyl (BVSM) to fabricate a ...biodegradable conduit for peripheral nerve repair. First, BVSM on the prepared conduit was characterized to determine its mechanical properties and contact angle. The maximum tensile strength and water contact angle of the gelatin-BVSM conduits were 23 ± 4.8 MPa and 74.7 ± 9°, which provided sufficient mechanical strength to resist muscular contraction; additionally, the surface was hydrophilic. Cytotoxicity and apoptosis assays using Schwann cells demonstrated that the gelatin-BVSM conduits are non-cytotoxic. Next, we examined the neuronal electrophysiology, animal behavior, neuronal connectivity, macrophage infiltration, calcitonin gene-related peptide localization and expression, as well as the expression levels of nerve regeneration-related proteins. The number of fluorogold-labelled cells and histological analysis of the gelatin-BVSM nerve conduits was similar to that observed with the clinical use of silicone rubber conduits after 8 weeks of repair. Therefore, our results demonstrate that gelatin-BVSM conduits are promising substrates for application as bioengineered grafts for nerve tissue regeneration.
PDF
