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In insects, RNAi is considered the major antiviral immune defense pathway. DsRNAs produced during viral infection are processed by Dicer enzymes into small RNAs that function as specificity determinants to silence viral genes. By contrast, in mammals, recognition of molecules associated with viral infection, such as dsRNA, by pattern recognition receptors (PRRs) initiates a signaling cascade that culminates in the production and release of signaling proteins with antiviral function such as interferons. However, in insects, the hypothesis that components of virions can be recognized as pathogen-activated molecular patterns (PAMPs) to activate the innate immune response has not been investigated systematically. In this study, the potential of VP1, that constitutes the major capsid protein of cytoplasmic polyhedrosis virus (CPV; Reoviridae), to activate a collection of immune-related genes was examined in silkworm-derived Bm5 cells. Two different methods of VP1 administration were tested, either through endogenous expression in transformed cell lines, or through addition of purified VP1-based viral-like particles to the extracellular medium. In addition, exposure to CPV virions isolated from purified polyhedra was also performed. In general, our results do not show a robust transcriptional response of immune-related genes to VP1 or CPV virions, but two exceptions were noted. First, the expression of the antimicrobial peptide (AMP) gene Attacin was strongly induced after 24 h of exposure to VP1-based VLPs. Second, the expression levels of dcr-2, an essential gene in the RNAi pathway, were greatly increased in VP1-expressing transformed Sf21 cells but not transformed Bm5 cells, indicating the existence of species-specific effects. However, the increased expression of dcr-2 did not result in increased silencing efficiency when tested in an RNAi reporter assay. Our study indicates that the capsid protein VP1 of CPV has the potential to act as a PAMP and to induce a transcriptional response in insect cells that relate both to RNAi and protein effectors such as AMPs. The identity of the PRRs and the signaling cascade that are potentially triggered by VP1 remain to be elucidated in future experiments. While this study was performed on a small scale, it can encourage more comprehensive studies with high-throughput approaches (microarray, deep sequencing) to search more systematically whether viral capsid proteins can act as PAMPs in insects and whether their production results in the induction of immune-related genes with potential antiviral function.

The classical baculovirus display system (BDS) has often recruited fields including gene delivery, gene therapy, and the genetic engineering of vaccines, as it is capable of presenting foreign polypeptides on the membranes of recombinant baculovirus through a transmembrane protein. However, classical BDS's high cost, complicated operation, low display efficiency and its inability to simultaneously display multiple gene products impede its practicality. In this study, we present a novel and highly efficient display system based on ires-dependent gp64 for rescuing gp64-null Bacmid of baculovirus construction without affecting the viral replication cycle, which we name the baculovirus multigene display system (BMDS). Laser scanning confocal microscopy demonstrated that eGFP, eYFP, and mCherry were translocated on the membrane of Spodoptera frugiperda 9 cell successfully as expected. Western blot analysis further confirmed the presence of the fluorescent proteins on the budded, mature viral particles. The results showed the display efficiency of target gene on cell surface is fourfold that of classical BDS. In addition, a recombinant baculovirus displaying three kinds of fluorescent proteins simultaneously was constructed, thereby demonstrating the effectiveness of BMDS as a co-display system.

Background Genetic variant is one of the causes of sepsis patients’ mortality. Now, many studies have identified several SNPs related to sepsis. However, none of these studies were identified in a genome-wide way. We aimed to detect genetic polymorphisms of sepsis patients. Methods The blood samples of eight normal controls and ten sepsis patients were collected for whole exome sequencing. Then, Single Nucleotide Polymorphisms (SNPs) were selected according to quality score and number of sepsis patients who had this variants. Synonymous mutations were removed. Genes including these remaining variants were used for functional analyses. After analyses, the remaining SNPs and indels were validated in 149 normal controls and 156 sepsis patients. Finally, serum levels of proteins coded by genes including these SNPs were evaluated. Results After whole exome sequencing, 97 SNPs and one indel site were left. Then, functional screening was performed. Only seven SNPs were used for further validation. As a result, the rs2721068 in dominant model and rs17446614 in recessive model were associated with sepsis, and the ORs of these two SNPs were 3.24 (95%CI, 1.25, 8.44) and 0.47 (0.026, 0.88), respectively. These two SNPs were both located in Forkhead box O1 (FOXO1) gene. For rs2721068 (T/T, T/C-C/C) and rs17446614 (A/A-A/G, G/G), serum levels of foxo1 in sepsis patients were both significantly lower in normal controls. Conclusions We firstly reported that the rs2721068 and rs17446614 were correlated to genetic predisposition to sepsis. Electronic supplementary material The online version of this article (10.1186/s12879-019-4330-7) contains supplementary material, which is available to authorized users.

Copper (Cu) is an essential trace element for growth and development and abnormal Cu levels are associated with anemia, metabolic disease and cancer. Evolutionarily conserved from fungi to humans, the high-affinity Cu+ transporter Ctr1 is crucial for both dietary Cu uptake and peripheral distribution, yet the mechanisms for selective permeation of potentially toxic Cu+ ions across cell membranes are unknown. Here we present X-ray crystal structures of Ctr1 from Salmo salar in both Cu+-free and Cu+-bound states, revealing a homo-trimeric Cu+-selective ion channel-like architecture. Two layers of methionine triads form a selectivity filter, coordinating two bound Cu+ ions close to the extracellular entrance. These structures, together with Ctr1 functional characterization, provide a high resolution picture to understand Cu+ import across cellular membranes and suggest therapeutic opportunities for intervention in diseases characterized by inappropriate Cu accumulation., Copper (Cu) is an essential trace element for growth and development and the Cu+ transporter Ctr1 is crucial for both dietary Cu uptake and peripheral distribution. Here authors solve Cu+ -free and Cu+ -bound Ctr1 structures which adopt a homo-trimeric Cu+ -selective ion channel-like architecture

High efficiency integration of functional microdevices into microchips is crucial for broad microfluidic applications. Here, a device-insertion and pressure sealing method was proposed to integrate robust porous aluminum foil into a microchannel for microchip functionalization which demonstrate the advantage of high efficient foil microfabrication and facile integration into the microfluidic chip. The porous aluminum foil with large area (10 × 10 mm2) was realized by one-step femtosecond laser perforating technique within few minutes and its pores size could be precisely controlled from 3 μm to millimeter scale by adjusting the laser pulse energy and pulse number. To verify the versatility and flexibility of this method, two kinds of different microchips were designed and fabricated. The vertical-sieve 3D microfluidic chip can separate silicon dioxide (SiO2) microspheres of two different sizes (20 and 5 μm), whereas the complex stacking multilayered structures (sandwich-like) microfluidic chip can be used to sort three different kinds of SiO2 particles (20, 10 and 5 μm) with ultrahigh separation efficiency of more than 92%. Furthermore, these robust filters can be reused via cleaning by backflow (mild clogging) or disassembling (heavy clogging).