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Bergamottin, a bioactive component of bergamot: dual inhibition of Japanese encephalitis virus internalization and genome replication.

Japanese encephalitis virus (JEV) is associated with high mortality and severe neurological sequelae, and existing prevention and control strategies remain insufficient. Therefore, the development of novel antiviral agents is of critical public health importance. This study systematically evaluated the antiviral activity and underlying mechanism of bergamottin, a natural product. Bergamottin exhibited significant dose-dependent inhibitory effects against JEV in multiple cell lines, including BHK-21, HuH-7, and Vero cells, demonstrating potent antiviral efficacy. Mechanistic investigations revealed that bergamottin primarily targeted the internalization and replication stages of the JEV life cycle, thereby effectively suppressing viral proliferation. Additionally, adaptive mutation screening indicated that the D389G mutation in envelope protein E confers drug resistance by potentially changing E protein conformation or reducing endocytic efficiency. In vivo experiment, bergamottin significantly reduced viral loads in mouse brain tissue and effectively improved the survival rate of infected mice. Our findings indicated that bergamottin exerted antiviral activity by dual targeting of key steps in the viral life cycle, making it a highly promising candidate for anti-JEV therapy. Further exploration of the antiviral properties of bergamottin is expected to facilitate its clinical development as a treatment for JEV infection.

Animals

Triacylglycerol metabolism is a novel target to combat West Nile virus infection.

West Nile virus (WNV) is a zoonotic Orthoflavivirus transmitted by mosquitoes that is responsible for outbreaks of meningitis and encephalitis worldwide. Driven by climate change, WNV has expanded as a global public health concern, particularly in temperate regions. However, there are still no specific approved therapies, reinforcing the need for antiviral development. Previous works have documented that WNV multiplication strictly depends on certain cellular lipids. To identify novel lipid-related therapeutic targets, we analyzed the infection driven alterations in the CNS lipidome, the primary tissue supporting WNV replication. Our results indicated that the major alterations in the brain lipid content of WNV-infected mice corresponded to triacylglycerols (TAGs). Moreover, transcriptomic analysis showed that infected brains underwent changes in the expression of TAG metabolism. Supplementation with exogenous fatty acids increased lipid droplets (LD) content and promoted viral replication in cell culture models. On the contrary, pharmacological intervention in TAG metabolism using diacylglycerol acyltransferase inhibitors (DGATi) suppressed WNV multiplication in cell culture models. As a proof-of-concept of the therapeutic potential of DGATi, treatment of mice with A922500 reduced viral burden in the brain and proinflammatory cytokine production. Overall, our results unveil the importance of LDs and glycerolipid metabolism for WNV and highlight the potential of therapeutic interventions targeting this pathway to control viral replication and neuroinflammation.

West Nile virus; lipid

Viral community in Aspergillus spp. isolated from commercially available fermented dried bonito.

Katsuobushi is a traditional processed seafood product used in Japanese-style cooking, and when it is produced through fermentation by fungi, it is called karebushi. The fungi involved in katsuobushi fermentation are collectively referred to as katsuobushi molds. We previously discovered seven novel viruses from katsuobushi molds and determined their genome sequences. However, our previous explorations used only nine fungal strains available from culture collections, leaving the diversity of viruses infecting fungi involved in katsuobushi fermentation unclear. Therefore, in this study, we aimed to isolate fungi from commercially available karebushi and clarify the prevalence of viruses in the isolates. Karebushi produced by three manufacturers was obtained, and 30 fungal strains (including Aspergillus spp.) were isolated from each. Double-stranded RNA (dsRNA) fractions were prepared from the mycelia of the isolated strains. Electrophoresis suggested that a relatively high proportion of the isolates harbored dsRNA elements consistent with RNA virus infection (30-70% per manufacturer; 59% overall). Furthermore, dsRNA sequencing identified four novel viruses in isolates of Aspergillus chevalieri and Aspergillus montevidensis: a beny-like virus, a gammapartitivirus, a narnavirus, and a victorivirus, in addition to two previously reported viruses. Notably, this represents the first report of a beny-like virus in Aspergillus spp. This study provides insights into the diversity of viruses infecting fungi involved in katsuobushi fermentation.

Aspergillus

A First-in-Japanese Phase 1, Double-Blind, Placebo-Controlled, Parallel-Cohort Study of Sefaxersen, an Antisense Oligonucleotide Targeting Complement Factor B, in Healthy Participants.

Increased activity in the complement alternative pathway (AP) plays a key role in diseases such as IgA nephropathy (IgAN). This first-in-Japanese double-blind Phase 1 study investigated the pharmacokinetics (PK), pharmacodynamics (PD), safety, and tolerability of sefaxersen (RO7434656), an antisense oligonucleotide targeting complement factor B messenger RNA. Healthy participants were randomized equally into four cohorts: placebo or sefaxersen 20, 40, or 70 mg. The PK, PD, and safety endpoints were monitored throughout the study and during the 90-day follow-up period. All 24 participants completed the study, with no new safety signals or clinically meaningful changes in blood chemistry, electrocardiogram, or vital signs observed. Plasma sefaxersen concentration demonstrated a biphasic PK profile, characterized by an initial rapid decline followed by a slow elimination. Sefaxersen decreased PD markers related to the complement AP selectively, without affecting the classical pathway, in a dose-dependent manner, and the PD effects persisted over 2 to 3 months. Sefaxersen was well tolerated by healthy Japanese participants, with a manageable safety profile. These findings support the inclusion of Japanese patients with IgAN in the global Phase 3 study (IMAGINATION, NCT05797610).

Humans

Early hepatic protein responses to dietary restriction-refeeding in Japanese quail: A proteomic investigation.

Feed intake and refeeding after nutrient scarcity induce rapid metabolic adaptations in the poultry liver; however, hepatic proteomic recovery pathways in the early hours post-refeeding remain poorly defined. This study aimed to characterize early liver protein signatures in Japanese quail (Coturnix japonica) recovering from nutritional stress under two refeeding conditions. Eighteen 12-week-old male quails (245.20 ± 0.213 g) were assigned to three groups (n = 6): control fed ad libitum (12.13 MJ/kg), 24 h feed deprivation followed by 6 h refeeding, and 24 h low metabolizable energy (6.30 MJ/kg) diet followed by 6 h refeeding. In total, 854 proteins were identified, of which 515 met the filtering criteria. The low metabolizable energy refeeding showed higher abundance of proteins linked to ATP binding and carbohydrate/carboxylic acid metabolism, alongside detoxification-related proteins, while suppressing translation/RNA-binding machinery and antioxidant pathways. Feed-deprived refeeding enriched in oxidative phosphorylation and mitochondrial complex I assembly with reduced cytoplasmic translation, NMD-related components, and sulfur compound metabolism. A direct comparison indicated divergent recovery strategies: low metabolizable energy refeeding mainly reflected oxidoreductase activity and translation initiation, whereas feed-deprived refeeding potentially enriched mitochondrial ATP production and glutathione-based defenses. Our analysis indicate that 6 h of refeeding initiates an early, incomplete recovery toward hepatic homeostasis, with the severity of prior nutritional restriction dictating distinct liver metabolic priorities. Collectively, these findings might provide a preliminary understanding of the hepatic mechanisms involved in recovery from nutrient deprivation and may help in the development of feeding strategies for managing metabolic recovery in poultry. However, these findings should be considered hypothesis-generating pending further validation.

Animals

Bi-compartmental CSF-serum analysis of NfL and GFAP differentiates central and peripheral pathology in neuroinfectious diseases: A monocentric real-world cohort study.

Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP), established biomarkers of neuroaxonal injury and astroglial pathology, are frequently only assessed in blood, which limits conclusions regarding their origin. Bi-compartmental analyses of CSF and serum may help differentiate central or peripheral origin of biomarker elevation. Moreover, studies on NfL and GFAP in distinct neuroinfectious disease (NID) phenotypes, particularly those based on real-world cohorts, are limited. This retrospective monocentric study analyzed CSF and serum from patients with (meningo-)encephalitis/myelitis (TI+; n&#xa0;=&#xa0;48), meningitis (TI-; n&#xa0;=&#xa0;80), (cranial) nerve palsies/polyradiculitis (PND; n&#xa0;=&#xa0;61), and 113 non-neuroinflammatory/non-neurodegenerative controls. A bi-compartmental model using scatter plots and simple linear regression was applied to assess the origin of blood biomarker levels and discriminate between central and peripheral pathology. CSF and serum NfL and GFAP z-scores were significantly higher in TI+ compared with TI- (CSF-GFAP p&#xa0;<&#xa0;0.001/sGFAP p&#xa0;=&#xa0;0.0083; CSF-NfL p&#xa0;=&#xa0;0.003/sNfL p&#xa0;=&#xa0;0.0004). TI+ and PND differed only in GFAP levels, which were higher in TI+ (CSF-GFAP p&#xa0;=&#xa0;0.0049/sGFAP p&#xa0;=&#xa0;0.003). The overall group effect (p&#xa0;&#x2264;&#xa0;0.003) and principal findings remained significant after adjustment for age, sex, QAlb, and time since (symptom) onset to LP. Bi-compartmental analysis revealed simultaneous elevation of CSF and serum NfL in TI+, indicating predominantly central origin, whereas PND demonstrated a shift toward higher sNfL levels suggesting peripheral origin. Higher clinical severity (modified Rankin Scale 3-5) was associated with elevated serum and CSF GFAP and NfL (sGFAP p&#xa0;=&#xa0;0.012/sNfL p&#xa0;=&#xa0;0.002; CSF-GFAP p&#xa0;<&#xa0;0.0001/CSF-NfL p&#xa0;=&#xa0;0.0001), which also predicted unfavorable outcome at discharge (sGFAP p&#xa0;=&#xa0;0.006/sNfL p&#xa0;=&#xa0;0.004; CSF-GFAP p&#xa0;=&#xa0;0.003/CSF-NfL p&#xa0;=&#xa0;0.012). NfL and GFAP were associated with brain/myelon involvement in NID, predominantly reflecting central pathology. Despite strong CSF-serum correlations, bi-compartmental approaches provide additional insight into biomarker origin and disease compartment.

Humans

Proteomic serum profiles before and after lipoprotein apheresis in patients with peripheral artery disease with ulceration.

INTRODUCTION: The efficacy of lipoprotein apheresis (LA) in peripheral arterial disease (PAD) has been primarily attributed to its anti-atherosclerotic effects through the adsorption of lipoproteins. However, the other potential effects of LA remain unknown. We evaluated changes in serum profiles before and after LA using a comprehensive analysis to explore the underlying mechanism. METHODS: Ten patients with leg ulcers were included from the LETS-PAD study, in which patients with lipoprotein-controlled PAD underwent LA. Serum samples collected at baseline and 1&#x2009;month after LA were analyzed for proteomic changes. RESULTS: Six patients exhibited ulcer epithelialization and skin perfusion pressure improvement. Proteomic analysis identified 2033 proteins. Fifty-five proteins showed significant differences. B-cell lymphoma protein-2 associated X (BAX) and C-X-C motif chemokine 10 (CXCL10) were downregulated. CONCLUSION: Serum BAX and CXCL10 levels significantly decreased after LA, which may be involved in the ulcer epithelialization mechanism of LA, which potentially acts through angiogenesis promotion.

Humans

Exploratory identification and cellular functional characterization of ppiabl as a candidate gene associated with growth traits in Paralichthys olivaceus.

The Japanese flounder (Paralichthys olivaceus) is an important mariculture species. However, the genetic mechanisms underlying its growth traits remain poorly understood. To explore the genetic basis of growth variation, whole-genome resequencing was performed in a cultured cohort of 60 individuals, followed by exploratory genome-wide association analysis and candidate-gene prioritization. The results revealed heritability estimates of 0.40 for body weight and 0.24 for body length, with substantial overlap in associated loci between the two traits. Exploratory association and variant-annotation analyses prioritized ppiabl, which carries a nonconservative missense variant, as a candidate gene for further investigation. Tissue expression analysis showed that ppiabl was highly expressed in muscle tissue. This gene encodes a protein belonging to the conserved peptidyl-prolyl cis-trans isomerase family. In Japanese flounder primary muscle cells, ppiabl knockdown was associated with altered expression of growth-related genes and an increased G1-phase fraction, whereas overexpression produced changes in the opposite direction. In line with this, fast-growing individuals were found to have significantly larger muscle fiber areas than slow-growing ones. These findings suggest that ppiabl may be involved in muscle-related cellular processes associated with growth variation in Japanese flounder, although its contribution to whole-animal growth requires further validation. Overall, this exploratory study prioritizes ppiabl as a candidate gene potentially associated with growth-related cellular processes in Japanese flounder, although validation in larger independent populations and in vivo models is required.

Animals

Durability and Safety of Imeglimin as an Add-On to DPP-4 Inhibitors in Japanese Type 2 Diabetes: The 104-Week FAMILIAR Trial.

AIMS: To evaluate the long-term efficacy and safety of imeglimin added to dipeptidyl peptidase-4 (DPP-4) inhibitors in Japanese patients with type 2 diabetes, focusing on glycemic durability and safety in elderly patients over 104&#x2009;weeks. MATERIALS AND METHODS: This multicenter, randomized, placebo-controlled trial comprised a 24-week double-blind phase (imeglimin 1000&#x2009;mg or placebo twice daily) followed by an 80-week open-label extension in which all patients received imeglimin. Eligible patients had inadequate glycemic control despite DPP-4 inhibitor monotherapy. The main assessment measured HbA1c changes from baseline to week 104. Secondary assessments included meal tolerance tests (MTT) for evaluating physiological changes in &#x3b2;-cell function and insulin resistance and safety monitoring. RESULTS: Of 117 randomized patients, 81 completed 104&#x2009;weeks. In the early-start group that received imeglimin from week 0, the significant HbA1c reduction observed at week 24 (-0.65%) was maintained through week 104 (-0.55%; p&#x2009;<&#x2009;0.001 vs. baseline). The delayed-start group that switched to imeglimin at week 24 achieved similar glycemic control thereafter. Elderly patients (&#x2265;&#x2009;65&#x2009;years) in the early-start group maintained stable HbA1c reduction (-0.58%) without hypoglycemic events over 2&#x2009;years. MTT analysis in the early-start group showed sustained improvements in glucose AUC and insulin sensitivity without unnecessary insulin secretion over time. CONCLUSIONS: Imeglimin added to DPP-4 inhibitors appeared to improve glycemic control for 104&#x2009;weeks, without clear attenuation. The combination was well-tolerated with a low risk of hypoglycemia even in elderly patients. The long-term effect may be associated with improvements in insulin sensitivity. TRIAL REGISTRATION: jRCTs061210082.

Humans

Effect of transcutaneous vagus nerve stimulation in hemodialysis patients: A randomized controlled trial.

INTRODUCTION: Transcutaneous auricular vagus nerve stimulation (tVNS) has shown potential in neurological, autoimmune, and cardiovascular disorders, but its effects on HD patients remain unclear. This study aimed to evaluate the efficacy and safety of tVNS in HD patients. METHODS: We conducted a randomized controlled clinical trial on patients receiving HD &#x2265;6&#x2009;months. The tVNS group received stimulation for 1&#x2009;h during the first 2&#x2009;h of HD sessions, three times weekly for 8&#x2009;weeks, while the control group received standard care. The primary outcomes were dialysis efficiency (Single-pool Kt/V, Sp Kt/V) and dialysis-related symptoms (Dialysis Symptom Index, DSI), assessed every 4&#x2009;weeks. Secondary outcomes included pain and fatigue scores, physical performance, Hemodialysis Comfort Scale, hemoglobin levels, Mini-Mental State Examination, and anxiety and depression scores, measured at baseline and 8&#x2009;weeks after intervention. RESULTS: A total of 63 patients were enrolled in the study, with 32 patients assigned to the tVNS group and 31 patients to the control group. At 8&#x2009;weeks, the tVNS group showed significant improvements in Sp Kt/V (1.31&#x2009;&#xb1;&#x2009;0.11 vs. 1.25&#x2009;&#xb1;&#x2009;0.10, p&#x2009;=&#x2009;0.02), and DSI (12.09&#x2009;&#xb1;&#x2009;5.84 vs. 16.26&#x2009;&#xb1;&#x2009;5.27, p&#x2009;=&#x2009;0.004), as well as reductions in pain and fatigue, and increases in physical function, comfort, and hemoglobin. However, there were no statistically significant changes observed in cognitive function, anxiety, or depression. CONCLUSIONS: tVNS could improve dialysis efficiency, symptoms, and physical function in HD patients, indicating it may have a role as a complementary therapy.

Humans

Long-term safety of oral orforglipron in Japanese participants with type 2 diabetes (ACHIEVE-J): a multicentre, randomised, open-label, parallel-group phase 3 trial.

BACKGROUND: Orforglipron, an oral GLP-1 receptor agonist, requires further evaluation in east Asian populations with type 2 diabetes, given this group's distinct pathophysiological characteristics. This study aimed to assess orforglipron as add-on treatment to diet and exercise alone or to oral antihyperglycaemic medications in Japanese participants with type 2 diabetes. METHODS: This multicentre, randomised, open-label phase 3 study was conducted in 40 medical research centres and hospitals in Japan. Adults with type 2 diabetes and elevated glucose levels managing their condition with diet and exercise alone or with one or two oral antihyperglycaemic medications were assigned (1:1:1) via computer-generated random sequence to receive once-daily oral orforglipron (3 mg, 12 mg, or 36 mg). Randomisation was stratified by background therapy, baseline HbA1c (&#x2264;8&#xb7;5% or >8&#xb7;5%), and metformin use (yes vs no; applied only to &#x3b1;-glucosidase inhibitors, thiazolidinedione, and glinides). Investigators, participants, and site staff were not masked to treatment. The primary endpoint was safety for 52 weeks, assessed in all randomly assigned participants who received at least one dose of orforglipron. This study is registered with ClinicalTrials.gov, NCT06010004 (ACHIEVE-J). FINDINGS: Between Sept 28, 2023, and June 5, 2025, 450 participants were screened and 401 were randomly assigned to three groups (3 mg, n=132; 12 mg, n=135; and 36 mg, n=134). 352 (88%) completed study treatment. 339 participants (85%, 95% CI 80&#xb7;7-87&#xb7;8) had at least one treatment-emergent adverse event (TEAE), more frequently in the 36-mg group (118 [88%, 95% CI 81&#xb7;5-92&#xb7;5]) than in the 3-mg (107 [81%, 73&#xb7;5-86&#xb7;8]) and 12-mg (114 [84%, 77&#xb7;4-89&#xb7;6]) groups. Most TEAEs were of mild (267 [67%, 61&#xb7;8-71&#xb7;0]) or moderate (63 [16%, 12&#xb7;5-19&#xb7;6]) severity. Discontinuations due to an adverse event occurred in 19 of 134 participants (14%, 95% CI 9&#xb7;3-21&#xb7;1) in the 36-mg group compared with seven of 132 (5%, 2&#xb7;6-10&#xb7;5) in the 3-mg group and 11 of 135 (8%, 4&#xb7;6-14&#xb7;0) in the 12-mg group. Across treatment groups, gastrointestinal symptoms were the most common TEAEs leading to study treatment discontinuation (3 mg: 5 [3&#xb7;8%, 1&#xb7;6-8&#xb7;6]; 12 mg: 8 [5&#xb7;9%, 3&#xb7;0-11&#xb7;3]; and 36 mg: 11 [8&#xb7;2%, 4&#xb7;7-14&#xb7;1]). Level 2 (blood glucose <54 mg/dL) hypoglycaemia events occurred in three of 135 participants in the 12-mg group (2%, 0&#xb7;8-6&#xb7;3) and in three of 134 in the 36-mg group (2%, 0&#xb7;8-6&#xb7;4) groups. No level 3 (severe) hypoglycaemia events occurred. Outcomes were generally similar across background therapies. INTERPRETATION: Treatment with orforglipron in combination with diet and exercise alone or one or two oral antihyperglycaemic medications for 52 weeks demonstrated an acceptable safety profile in Japanese adults with type 2 diabetes. FUNDING: Eli Lilly. TRANSLATION: For the Japanese translation of the abstract see Supplementary Materials section.

Aged

A reanalysis of the Hitachi cohort study evaluating the effectiveness of low-dose CT screening for lung cancer.

The effectiveness of low-dose thoracic computed tomography (CT) screening for lung cancer for non-smokers or light smokers has been unclear. The results of the Hitachi cohort study performed by the conventional multivariable analysis suggested the reduction of lung cancer mortality by thoracic CT screening, but also revealed the lower all-cause mortality in the CT group, which indicated the existence of self-selection bias. Because the background of the subjects in the CT screening group and that in the X-ray screening group were very different, it is critical to adjust appropriately the confounding factors. In this brief report, we describe a re-evaluation of the results of the Hitachi Cohort Study performed by using more flexible methods, propensity score matching and inverse probability weighting.

epidemiology/public health

A multicenter randomized phase II/III trial of salvage treatment for refractory primary central nervous system lymphoma using tirabrutinib: JCOG2314 (ReSTART).

Primary central nervous system lymphoma (PCNSL) is an aggressive malignancy. Patients refractory to high-dose methotrexate-based induction therapy have an extremely poor prognosis. Although whole-brain radiotherapy (WBRT) is the standard salvage treatment and provides potent tumor control, early functional deterioration and late neurocognitive toxicity remain major concerns. A phase I/II trial on relapsed or refractory PCNSL demonstrated favorable efficacy and tolerability of tirabrutinib, a second-generation selective Bruton's tyrosine kinase inhibitor. Tirabrutinib's oral administration has enabled outpatient management. However, its clinical value for induction-refractory PCNSL remains uncertain. We designed a multicenter, randomized phase II/III trial (JCOG2314) to assess the non-inferiority of tirabrutinib to WBRT in overall survival and its potential to reduce functional deterioration and cognitive impairment. A total of 94 patients from 49 institutions will be enrolled over 4 years. The trial has been registered in the Japan Registry of Clinical Trials (study number: jRCT1031250645).

Humans

Voluntary Knowledge Brokering to Promote Evidence-Based Nursing Practice: A Qualitative Study.

Knowledge brokering is a process of connecting knowledge producers with users to facilitate evidence-based practice through relationship building and information sharing. This descriptive qualitative study aimed to clarify knowledge brokering by nurses in Japanese hospitals. Twelve registered nurses in Japanese hospitals participated. They had over 5&#x2009;years' clinical experience, including experience in conducting research, particularly staff research, and education. Data were collected through semi-structured individual interviews and analyzed using qualitative content analysis. The analysis revealed a central theme: continuous efforts to foster empathy among colleagues and spontaneously promote evidence-based practice: multifaceted brokering activities by clinical nurses. Findings identified 10 categories categorized into four interconnected gears: establishing the foundational ground, assessing clinical needs and staff readiness, tailoring and diffusing evidence, and sustaining and evolving evidence-based practice. Even nurses without formal titles voluntarily bridged the research-practice gap, providing new insights into informal brokering. Brokers communicated considerately, balanced evidence with clinical context, negotiated practical compromises, and fostered staff research competency.

Humans

O'nyong-nyong virus adaptive mutations in non-structural protein 1 and 3 enhance RNA replication and overcome FHL1 requirement.

Arthritogenic alphaviruses, like o'nyong-nyong virus (ONNV), cause debilitating musculoskeletal diseases and are geographically expanding. To predict their emergence, we seek to better understand evolutionary mechanisms that enable changes in virus tropism. Here, we identify adaptive mutations in the ONNV non-structural proteins (nsPs) that arose during cellular serial passaging and enabled ONNV to infect non-permissive Lunet cells. Using shotgun proteomics, we show that this human hepatoma cell line lacks the four-and-a-half-LIM domain protein 1 (FHL1), an essential host factor in ONNV RNA replication. Individual single nucleotide mutations in the nsP1 ring-aperture membrane-binding and oligomerization domain, the nsP3 macrodomain, and the nsP3 opal stop codon overcome FHL1 deficiency in Lunet cells by enhanced RNA replication. These findings demonstrate how subtle genomic changes in nsPs can profoundly influence alphavirus replication and tropism.

LIM Domain Proteins

MARK1 suppresses infectious bursal disease virus replication via phosphorylating VP3.

Infectious bursal disease virus (IBDV) of the Birnaviridae family is a non-envelope, double-stranded RNA virus that encodes a VP3 protein with multiple functions, which controls viral genome replication, IFN-&#x3b2; production, and virus traffic in infected cells. Posttranslational modifications (PTMs), such as ubiquitination, of VP3 have been demonstrated for affecting its function and stability. To clarify the mechanism by which VP3 is regulated in IBDV infected cells, we focused on the phosphorylation of VP3. Mass spectrometry analysis identified that microtubule-affinity regulating kinases 1 (MARK1) was a kinase interacting protein of VP3. Inhibitory function of MARK1 in affecting viral replication was validated. We describe the phosphorylation event at the serine 130 (S130) and serine 163 (S163) residues of VP3 mediated by MARK1 via mass spectrometry analysis. Alanine replacement of the phosphorylation sites in VP3 significantly enhanced its RNA-binding activity. Additionally, the mutation of two serine residues led to remarkably improved in its polymerase-enhancing function. We then incorporated the two mutations to rescue recombinant IBDV. Viral growth curve analysis revealed that replication of mutant IBDV was significantly enhanced relative to wild type (WT) virus. In conclusion, we found that VP3 functions are specifically regulated by MARK1 mediated phosphorylation at S130 and S163 and that this regulation suppresses IBDV replication ultimately.

Infectious bursal disease virus

In Situ Hybridization and RT-PCR Detection of Nervous Necrosis Virus in Fourfinger Threadfin, Eleutheronema tetradactylum, in Taiwan.

Between April and July 2020, suspected outbreaks of nervous necrosis virus (NNV) infection were observed in fourfinger threadfin (Eleutheronema tetradactylum) fingerling hatcheries in Pingtung County, southern Taiwan. Affected fish exhibited spiral swimming behaviour and abdominal distension, resulting in mortality rates between 50% and 100%. Histopathological examination showed severe vacuolation in the brain and ocular tissues, with large oval and/or irregular basophilic cytoplasmic inclusion bodies in the brain. Phylogenetic analysis of the viral replicase (RNA1) and capsid protein (RNA2) genes revealed high nucleotide sequence identities among the isolates in this study, with sequence similarity rates of 96.9%-99% for RNA1 and 98.2%-99.0% for RNA2 compared to RGNNV reference strains available in the NCBI GenBank database. This is the first detection of betanodavirus in fourfinger threadfin in Taiwan, using RT-PCR and ISH. A positive correlation between elevated water temperatures and disease severity indicates the need for year-round surveillance and genomic analysis to clarify the epidemiology of FTNNV. The data suggest that infected eggs may facilitate the vertical transmission of Betanodavirus. Crucially, utilising virus-free broodstock, alongside routine health screening and environmental control, is essential for mitigating NNV risks in fourfinger threadfin aquaculture.

Animals