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Infectious hematopoietic necrosis virus (IHNV) is the causative pathogen of infectious hematopoietic necrosis, outbreaks of which are responsible for significant losses in rainbow trout aquaculture. Strains of IHNV isolated worldwide have been classified into five major genogroups, J, E, L, M, and U. To date, comparative transcriptomic analysis has only been conducted individually for the J and M genogroups. In this study, we compared the transcriptome profiles in U genogroup and J genogroup IHNV-infected RTG-2 cells with mock-infected RTG-2 cells. The RNA-seq results revealed 17,064 new genes, of which 7,390 genes were functionally annotated. Differentially expressed gene (DEG) analysis between U and J IHNV-infected cells revealed 2,238 DEGs, including 1,011 downregulated genes and 1,227 upregulated genes. Among the 2,238 DEGs, 345 new genes were discovered. The DEGs related to immune responses, cellular signal transduction, and viral diseases were further analyzed. RT-qPCR validation confirmed that the changes in expression of the immune response-related genes trpm2, sting, itgb7, ripk2, and irf1, cellular signal transduction-related genes irl, cacnb2, bmp2l, gadd45α, and plk2, and viral disease-related genes mlf1, mtor, armc5, pik3r1, and c-myc were consistent with the results of transcriptome analysis. Taken together, our findings provide a comprehensive transcriptional analysis of the differential virulence of the U and J genogroups of IHNV, and shed new light on the pathogenic mechanisms of IHNV strains.

DDX3, a member of the DEAD-box RNA helicase family and has highly conserved ATP-dependent RNA helicase activity, has important roles in RNA metabolism and innate anti-viral immune responses. In this study, five transcript variants of the DDX3 gene were cloned and characterized from rainbow trout (Oncorhynchus mykiss). These five transcript variants of DDX3 encoded proteins were 74.2 kDa (686 aa), 76.4 kDa (709 aa), 77.8 kDa (711 aa), 78.0 kDa (718 aa), and 78.8 kDa (729 aa) and the predicted isoelectric points were 6.91, 7.63, 7.63, 7.18, and 7.23, respectively. All rainbow trout DDX3 proteins contained two conserved RecA-like domains that were similar to the DDX3 protein reported in mammals. Phylogenetic analysis showed that the five cloned rainbow trout DDX3 were separate from mammals but clustered with fish, especially Northern pike (Esox lucius) and Nile tilapia (Oreochromis niloticus). RT-qPCR analysis showed that the DDX3 gene was broadly expressed in all tissues studied. The expression of DDX3 after infectious hematopoietic necrosis virus (IHNV) infection increased gradually after the early stage of IHNV infection, decreased gradually with the proliferation of IHNV in vivo (liver, spleen, and kidney), and was significantly decreased after the in vitro infection of epithelioma papulosum cyprini (EPC) and rainbow trout gonad cell line-2 (RTG-2) cell lines. We also found that rainbow trout DDX3 was significantly increased by a time-dependent mechanism after the poly I:C treatment of EPC and RTG cells; however no significant changes were observed with lipopolysaccharide (LPS) treatment. Knockdown of DDX3 by siRNA showed significantly increased IHNV replication in infected RTG cells. This study suggests that DDX3 has an important role in host defense against IHNV infection and these results may provide new insights into IHNV pathogenesis and antiviral drug research.

There are numerous articles published for geographical discrimination of tea. However, few research works focused on the authentication and traceability of Westlake Longjing green tea from the first- and second-grade producing regions because the tea trees are planted in a limited growing zone with identical cultivate condition. In this work, a comprehensive analytical strategy was proposed by ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry-based untargeted metabolomics coupled with chemometrics. The automatic untargeted data analysis strategy was introduced to screen metabolites that expressed significantly among different regions. Chromatographic features of metabolites can be automatically and efficiently extracted and registered. Meanwhile, those that were valuable for geographical origin discrimination were screened based on statistical analysis and contents in samples. Metabolite identification was performed based on high-resolution mass values and tandem mass spectra of screened peaks. Twenty metabolites were identified, based on which the two-way encoding partial least squares discrimination analysis was built for geographical origin prediction. Monte Caro simulation results indicated that prediction accuracy was up to 99%. Our strategy can be applicable for practical applications in the quality control of Westlake Longjing green tea.

Infectious pancreatic necrosis virus (IPNV) is a common pathogen that causes huge economic losses for the salmonid aquaculture industry. Autophagy plays an important regulatory role in the invasion of pathogenic microorganisms. In this study, we explored the relationship between IPNV infection and autophagy in Chinook salmon embryo (CHSE-214) cells using standard methods. Transmission electron microscopy showed that IPNV infection produced typical structures of autophagosomes in CHSE-214 cells. Transformation of microtubule-associated protein 1 light chain 3 (LC3)-I to LC3-II protein, a marker of autophagy, was observed in IPNV-infected cells using confocal fluorescence microscopy and western blot analysis. Western blotting also showed that expression of the autophagy substrate p62 was significantly decreased in IPNV-infected cells. The influence of autophagy on IPNV multiplication was further clarified with cell culture experiments using autophagy inducer rapamycin and autophagy inhibitor 3-methyladenine. Rapamycin promoted IPNV multiplication at both the nucleic acid and protein levels, which led to higher IPNV yields; 3-methyladenine treatment had the opposite effect. This study has demonstrated that IPNV can induce autophagy, and that autophagy promotes the multiplication of IPNV in CHSE-214 cells.

Previous studies have shown reduced attention to the eyes in individuals with autism spectrum disorder (ASD). However, most eye-tracking evidence regarding this impairment has been derived from passive viewing tasks. Here, we compared the passive viewing of faces with an active task involving face identification with morphing faces. While typical controls prioritized the eyes over other facial features regardless of viewing condition, autistic children exhibited reduced eye-looking in passive viewing, but displayed increased attention allocation to the eyes when instructed to identify faces. The proportional eye-looking in ASD during facial recognition was negatively related to the autism symptoms severity. These findings provide evidence regarding the specific situations in which diminished eye-looking may rise in young ASD children.

OBJECTIVE: To study the efficacy of family rehabilitation treatment performed by parents under the guidance of professionals in children with autism spectrum disorder (ASD). METHODS: In the prospective study, 60 children with ASD, aged 24-60 months, were randomly divided into an observation group and a conventional group. The parents of the children in the conventional group received an online training on basic knowledge and rehabilitation training of ASD alone, and those in the observation group received the online training and performed family rehabilitation treatment under the guidance of a professional team. Psycho-Education Profile Third Edition (PEP-3) and Childhood Autism Rating Scale (CARS) were used to evaluate the changes in related abilities after intervention. RESULTS: After 6 months of intervention, the scores of all dimensions of the PEP-3 scale in the observation group and most dimensions of the conventional group significantly increased (P

Eutrophication is an important water environment issue facing global lakes. Diversion of water from external watersheds into lakes is considered as effective in ameliorating eutrophication and reducing algal blooms. Nevertheless, the changes in lake water environment caused by external water diversion, especially the influence of water diversion on the characteristics of dissolved organic matters (DOM), are still poorly understood. We therefore used a combination of EEM-PARAFAC, Principal Component Analysis (PCA), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to investigate the effects of water diversion from the Niulan River on DOM characteristics in Lake Dianchi. The results showed that the water diversion from the Niulan River significantly improved the water quality of Lake Dianchi, the concentrations of TN, TP, COD and Chla decreased rapidly, and the degree of humification of dissolved organic matter (DOM) increased, which was in sharp contrast with that of pre-implementation. Firstly, the diversion of water from the Niulan River mainly led to changes in the structure of pollution sources. The load of influent rivers and sewage treatment plants rich in lignin and tannins increased, and the input of terrestrial humus increased. Second, the improved water quality reduced algal enrichment and frequency of blooms, and reduced the release of lipid- and protein-riched algal-derived DOM. Finally, the hydraulic retention time of Lake Dianchi caused by water diversion was shortened, the hydrodynamic conditions were significantly improved, and the dissolved oxygen (DO) level gradually recovered, which played a positive role in improving the humification degree of DOM. Our findings provide new insights for exploring the improvement of eutrophic lake eco-environmental quality caused by water diversion projects.

Passive virus surveillance was performed in twenty-nine salmon and trout farms from seven provinces and districts in China during the period 2017–2020. A total of 25 infectious pancreatic necrosis virus (IPNV) isolates were obtained, mainly from rainbow trout (Oncorhynchus mykiss). The molecular evolution of these Chinese IPNV isolates and the previously reported Chinese IPNV strains ChRtm213 and WZ2016 was analyzed, based on their VP2 gene coding region sequences (CDS). All 27 Chinese IPNV isolates clustered within genogroups I and V, with 24 of the IPNV isolates belonging to genogroup I (including ChRtm213 and WZ2016), and only three isolates clustering in genogroup V. The Chinese genogroup I IPNV isolates lacked diversity, composing six haplotypes with 41 polymorphic sites, and the identity of nucleotide and amino acid sequences among the entire VP2 gene CDS from these isolates was 97.44%–100% and 98.19%–100%, respectively. Divergence time analyses revealed that the Chinese genogroup I IPNV isolates likely diverged from Japanese IPNV isolates in 1985 (95% highest posterior density (HPD), 1965–1997), and diverged again in 2006 (95% HPD, 1996–2013) in China. Each of the three Chinese genogroup V IPNV isolates has a unique VP2 gene CDS, with a total of 21 polymorphic sites, the identity of nucleotide and amino acid sequences among all VP2 gene CDS from these isolates was 98.5%–99.5% and 98.6%–99.0%, respectively. The data demonstrate that genogroups I and V are more likely the currently prevalent Chinese IPNV genotypes.

Chemoresistance has become a primary hurdle in the therapeutic outcome of hepatocellular carcinoma. Substantial evidences have demonstrated that microRNAs (miRNAs) are closely associated with the chemoresistance of hepatocellular carcinoma (HCC). Our investigation is aimed at testifying the influence of microRNA-15a-5p (miR-15a-5p)/eukaryotic translation initiation factor 4E (eIF4E) on hepatocellular carcinoma resistance to pirarubicin (THP). In our study, miR-15a-5p expression was increased in THP-treated HepG2 cells. Downregulation of miR-15a-5p blocked cell growth and elevated cell apoptosis of HepG2 cells treated with THP. Moreover, eIF4E was verified as a direct target of miR-15a-5p by binding its 3 ′ -UTR, which was confirmed by luciferase report experiment. Additionally, eIF4E was negatively associated with the miR-15a-5p expression in HepG2 cells. Mechanically, eIF4E was proven as a specific downstream of miR-15a-5p and mediated the effects of miR-15a-5p on cell viability and apoptosis of HepG2 cells treated with THP. These findings supported that miR-15a-5p facilitated THP resistance of hepatocellular carcinoma cells by modulating eIF4E, thus providing an experimental basis that miR-15a-5p might act as a novel diagnostic target in hepatocellular carcinoma resistance to THP.

While childhood-onset asthma is extensively modeled in labs and includes TH2 cell driven-, steroid-responsive, eosinophilic etiology, little is understood about late-onset asthma which presents as severe, steroid-resistant, and destructive neutrophilic disease with poor outcomes. Lack of appropriate disease models widens this knowledge gap leading to fewer therapies and poorer quality of life for neutrophilic asthma patients. Here, we discover that while conventional models of allergic asthma (relying on naïve sensitized mice acutely challenged with aerosolized ovalbumin) induces eosinophilic asthma, transient and recurrent aeroallergenic exposure over extended durations (as would occur in humans progressing into adulthood) reprograms the lung myeloid and lymphoid landscape to instigate neutrophilic asthma. Mice with such lung history harbor diverse clusters of lung-resident CD4+ TRM cells including a novel RORγt-negative-IL17A+ TH17 subset; the latter detectable in asthmatic adult human lungs. On allergen reencounter, these RORγt-negative TH17 cells, rapidly secrete IL-17A which signals into lung epithelial and stromal cells to express CXCL5 and induce neutrophilic asthma including peribronchial neutrophilia, vascular leakage and lung damage. We find that lung epithelial antigen presentation is crucial to regulate disease severity by skewing CD4+ TRM phenotypes in asthmatic lungs. Specifically, epithelial MHC-II supports TH1 TRM cells and IFNγ secretion; the latter being a potent suppressor of IL-17A-induced CXCL5 and airway neutrophilia. Thus, using a relevant model of the disease, we identify an ‘epithelium-lymphocyte-neutrophil’ circuitry as a critical regulator of late-onset neutrophilic asthma. Supported by NIH grants including HL147461 to F.T.K., HL142199 to K.A.B., HL136725 to M.R.J., GM120060 and HL111449 to L.J.Q., AI115053, HL135756, and HL137081 to J.P.M. and T32 HL007035 for support of trainees.

We present a case study of multimodal interaction design for public window displays. Using a classic fairytale as the theme story, a prototype system that integrates mobile, gesture, tangible, touchscreen, and puppet interfaces has been implemented. The preliminary field deployment results demonstrate that our interactive window is well-received, with a significantly extended duration of user's interaction time. We conclude with a discussion of lessons learned and potential new research problems for interactive public window design. We believe our findings are useful in future design for interactive shop windows, theater showcases, and exhibition displays.

A series of side-chain-type sulfonated poly(arylene ether ketone)s with high ion exchange capacity (IEC) values were prepared by polycondensation reaction of 4,4′-difluorobenzophenone with 2,2′-bis(3-amino-4-hydroxyphenyl) and bisphenol A, followed by post-grafting reaction using 1,4-butanesultone. For these obtained membranes, sulfoalkylamine functionalized poly(ether ether ketone) (SAm-PEEK)-0.8 with the highest IEC of 3.42 mequiv. g−1 displayed the highest proton conductivity of 0.11 S cm−1 at 25°C and 0.167 S cm−1 at 60°C, respectively. The morphology of these membranes was investigated by transmission electron microscope analysis. The result showed that these membranes exhibited well-connected hydrophilic channels due to their high IEC values and densely populated flexible acid side chains. Owing to their low methanol permeability and high selectivity, SAm-PEEK- x membranes are promising candidates for direct methanol fuel cell applications.

Here, a series of novel poly(ether ether ketone) containing sulfoalkylamine pendant groups (SNPEEK-x) were synthesized by grafting copolymerization reaction. The chemical structure of SNPEEK-x was identified by 1H NMR and the morphology of all films was measured by SAXS and TEM. The impedance varied for five orders of magnitude (from 107 to 102 Ω) as the relative humidity increasing from 11 to 97% RH. At the same time, all samples exhibited a fast response time of less than 3 s, outstanding repeatability and good long-term durability against high humidity. Especially, SNPEEK-x sensors displayed an extremely small humidity hysteresis in the impedance versus RH relationship during absorption and desorption processes. These essential properties of humidity sensors such as the impedance at various humidity, sensitivity, linearity and humidity hysteresis revealed that SNPEEK-x are suitable to be used as humidity sensors.

Infectious hematopoietic necrosis virus (IHNV) is the main pathogen threatening the aquaculture used by the salmonid industry worldwide. Our previous study showed that IHNV infection induced autophagy activation in epithelioma papulosum cyprinid (EPC) cells, but the relationship between IHNV infectivity and autophagy induction had not yet been addressed. To investigate this question, IHNV was inactivated by ultraviolet (UV) irradiation and the complete protein sequence of IHNV glycoprotein was segmented by pepscan into 43 peptides. The induction of autophagy was analyzed by transmission electron microscopy, confocal fluorescence microscopy, flow cytometry, and western blotting. The results show that UV-inactivated IHNV and viral glycoprotein can induce autophagosome formation, obvious punctate clusters of LC3-II and an elevated LC3-II to LC3-I ratio. All these results suggested that UV-inactivated IHNV and viral glycoprotein can induce autophagy independently of viral infectivity. The flow cytometry and western blotting results show that EPC cells treated with peptide p108 displayed an obvious induction of autophagy (LC3-II increased by approximately 2.5-fold). The cells pretreated with peptide p108 showed a significant inhibition of intracellular viral mRNA replication levels and extracellular viral yields of IHNV. These results suggest that peptide p108 could be a promising drug for use in IHNV prevention, and they lay a new foundation for anti-IHNV drug development.

In this paper, field effect transistors (FET) based on different kinds of non-graphene materials are introduced, which are MoS2, WSe2 and black phosphorus (BP). Those devices have their unique features in fabrication process compared with conventional FETs. Among them, MoS2 FET shows better electrical characteristics by applying a SiO2 protective layer; WSe2 FET is fabricated based on a new low pressure chemical vapor deposition (LPCVD) method; BP FET acquires high on/off ratio and high hole mobility by using a simple dry transfer method. Those novel non-graphene materials inspire new design and fabrication process of basic logic device.

Numerous studies have indicated the common deficit of Autism Spectrum Disorder (ASD) in recognizing and understanding facial expressions, which is a major cause of the ASD’s social dysfunction. Emotional sensitivity to facial expression is a prerequisite of understanding and recognizing facial expression. However, the emotion sensitivity to facial expressions in ASD has yet to be systematically analyzed to date. After systematic analysis of existing studies about ASD and the perception of facial expression, we found that the existing literature could be sorted into three task categories: explicit observation of facial emotion, fixation-oriented observation of facial emotion, or implicit observation of facial emotion. We then analyzed the peripheral physiological and neuroimaging data of ASD and facial emotion perception under those three conditions. We found that the lack of emotion sensitivity to facial expressions was mainly observed in the explicit or fixation-oriented affect recognition tasks, either of which required intentional focus on key features of facial expression. By contrast, subjects with ASD exhibited similar or even larger amygdala activation compared to healthy subjects when implicitly processing emotional facial expressions. These results suggest that individuals with ASD are not lacking emotional sensitivity to facial expression in nature. Instead, the insufficient face adaptation and the face-specific hyperarousal that characterize ASD may lead the patients to avoid attention orienting to facial expression, which in turn leads to deficient activation in emotion-related neural circuits. Based on these evidences, we propose a new method of intervention for improving the facial emotion sensitivity in ASD patients. That is, training ASD patients to perceive emotional faces implicitly, without conscious awareness of facial emotion observation, is a potentially promising approach to improve autistic individuals’ neural sensitivity and adaptation to facial expressions. This may be an important candidate method for the intervention of autistic symptoms and the enhancement of their social functions.

The complete mitochondrial genome (mitogenome) of Bactrocera proprediaphora (Diptera: Tephritidae: Dacinae) was sequenced and annotated. The mitochondrial genome is 15,829 bp (GenBank No. MN688227)...

The complete mitochondrial genome (mitogenome) of the Bactrocera rubigina (Diptera: Tephritidae: Dacinae) was sequenced and annotated. The mitochondrial genome was 15,285 bp (GenBank No. MN...

There are numerous articles published for geographical discrimination of tea. However, few research works focused on the authentication and traceability of Westlake Longjing green tea from the first- and second-grade producing regions because the tea trees are planted in a limited growing zone with identical cultivate condition. In this work, a comprehensive analytical strategy was proposed by ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry-based untargeted metabolomics coupled with chemometrics. The automatic untargeted data analysis strategy was introduced to screen metabolites that expressed significantly among different regions. Chromatographic features of metabolites can be automatically and efficiently extracted and registered. Meanwhile, those that were valuable for geographical origin discrimination were screened based on statistical analysis and contents in samples. Metabolite identification was performed based on high-resolution mass values and tandem mass spectra of screened peaks. Twenty metabolites were identified, based on which the two-way encoding partial least squares discrimination analysis was built for geographical origin prediction. Monte Caro simulation results indicated that prediction accuracy was up to 99%. Our strategy can be applicable for practical applications in the quality control of Westlake Longjing green tea.

Salmonids can be co-infected by infectious hematopoietic necrosis virus (IHNV) and infectious pancreatic necrosis virus (IPNV) under natural or experimental conditions. To reveal the influence of IPNV on IHNV in co-infections, CHSE-214 cells were inoculated with IPNV at different time intervals prior to or after IHNV infection. Propagation of IHNV was determined by an immunofluorescence antibody test, real-time quantitative polymerase chain reaction, flow cytometry, and virus titration. The results showed that when cells were inoculated with IPNV prior to IHNV, IHNV multiplication was inhibited. This inhibitory effect became stronger with increasing time intervals (P 0.05). When cells were inoculated with IPNV after IHNV, the inhibitory effect became weaker with increasing time intervals (P 0.05), and no significant inhibition was observed at 12 h (P 0.05) compared with the single IHNV infection group. The findings suggest that IHNV is inhibited at the early stage of infection by IPNV and in a time dependent manner during co-infection. Furthermore, the effect of IPNV on IHNV entry and expression of IHNV entry-related genes clathrin, dynamin-2, adaptor protein 2, and vacuolar protein sorting 35 were also determined. The results showed that IPNV did not affect the amount of IHNV entering the cells. However, the expression levels of clathrin and dynamin-2 were significantly lower in co-infection than those in single IHNV infection, which suggests that IPNV likely inhibits IHNV by affecting IHNV invasion via downregulating IHNV entry-related genes clathrin and dynamin-2.

Infectious pancreatic necrosis virus (IPNV) and infectious hematopoietic necrosis virus (IHNV) are two common viral pathogens that cause severe economic losses in all salmonid species in culture, but especially in rainbow trout. Although vaccines against both diseases have been commercialized in some countries, no such vaccines are available for them in China. In this study, a recombinant virus was constructed using the IHNV U genogroup Blk94 virus as a backbone vector to express the antigenic gene, VP2, from IPNV via the reverse genetics system. The resulting recombinant virus (rBlk94-VP2) showed stable biological characteristics as confirmed by virus growth kinetic analyses, pathogenicity analyses, indirect immunofluorescence assays and western blotting. Rainbow trout were immunized with rBlk94-VP2 and then challenged with the IPNV ChRtm213 strain and the IHNV Sn1203 strain on day 45 post-vaccination. A significantly higher survival rate against IHNV was obtained in the rBlk94-VP2 group on day 45 post-vaccination (86%) compared with the PBS mock immunized group (2%). Additionally, IPNV loads decreased significantly in the rBlk94-VP2 immunized group in the liver (28.6-fold to 36.5-fold), anterior kidney (21.7-fold to 44.2-fold), and spleen (14.9-fold to 22.7-fold), as compared with the PBS mock control group. The mRNA transcripts for several innate and adaptive immune-related proteins (IFN-γ, IFN-1, Mx-1, CD4, CD8, IgM, and IgT) were also significantly upregulated after rBlk94-VP2 vaccination, and neutralizing antibodies against both IHNV and IPNV were induced on day 45 post-vaccination. Collectively, our results suggest that this recombinant virus could be developed as a vaccine vector to protect rainbow trout against two or more diseases, and our approach lays the foundations for developing live vaccines for rainbow trout.

Recent increases in concentrations of chemical oxygen demand (COD-Cr) in Dianchi Lake, China, is an important factor affecting its water quality. Large volumes of cyanobacteria algae have also been recorded in this lake; its growth, distribution and metabolism are believed to directly or indirectly affect water quality. The relationship between metabolism of cyanobacteria and COD-Cr in Dianchi Lake, and the causes of this relationship, are examined in this study. Results show that the increase of COD-Cr concentration is closely related to the metabolism of algae, and that organic substances containing nitrogen and sugars, produced by metabolism, contribute to an increase of COD-Cr to a certain extent. The characteristics of fluorescence spectra of dissolved organic matter (DOM) in the Waihai area of Dianchi Lake are similar to those of algae culture water, and their dominant substances are protein-like substances. Algae release organic substances into water during its growth cycle and extracellular organic substances are mainly released during its normal growth and metabolism stages. Once algae cells enter the decline stage, internal organic matter is released during the dying and decomposition stages, resulting in a distinct increase of COD-Cr. A high concentration of organic matter is present in Dianchi Lake sediments, dominated by native organic matter predominantly derived from aquatic plants and plankton. This finding indicates a potential long-term risk of organic pollutants being released from dead algae cells into the lake. PRACTITIONER POINTS: There is a distinct positive correlation between COD-Cr and Chl-a concentration in Dianchi Lake. Organic substances containing nitrogen and sugars produced by algae metabolism contributed to COD-Cr. The cells die and decompose organic matter content in the water substantially increases, resulting in a distinct increase of COD-Cr. Weight >20 kDa are mainly released into the water body during the decomposition of algae cells after mortality. Organic matter content in the water substantially increases, resulting in a distinct increase of COD-Cr.

Complicated viral interactions make viral co-infections more difficult to treat. Co-infection of infectious hematopoietic necrosis virus (IHNV) and infectious pancreatic necrosis virus (IPNV) causes huge economic losses to the salmonid industry in China. To reveal the impact of IHNV on IPNV during co-infection, Chinook salmon embryo (CHSE-214) cells were inoculated with IHNV prior to or after IPNV at different time intervals, and propagation of IPNV was determined at the RNA, protein, and virion levels by real-time quantitative polymerase chain reaction (RT-qPCR), an immunofluorescence antibody test (IFAT), flow cytometry, and virus titration. Taken together, the results showed that IPNV multiplication was enhanced in all of the co-infection groups compared with the single IPNV infection group. This enhancement became stronger with an increasing infection time interval irrespective of the infection order, and the highest IPNV multiplication level was observed when IHNV was inoculated 12 h after IPNV (P12H). Compared with the single IPNV infection group, the IPNV RNA level in the P12H group was at least 10-fold higher, the proportions of IPNV-infected cells determined by IFAT and flow cytometry were approximately 2-fold higher, and the viral titer was about 40-fold higher. A significant difference was detected between each group in which IHNV was inoculated after IPNV. These findings suggested that a synergistic effect was induced by IHNV over IPNV, and IPNV multiplication was enhanced during co-infection in CHSE-214 cells. This enhancement was dependent on the infection time interval but not the infection order and the synergistic effect became stronger with increasing infection time interval within the study period.