A comparison of biological characteristics of three strains of Chinese sacbrood virus in Apis cerana

Over One Million DNA and Protein Events Through Ultra-Stable Chemically-Tuned Solid-State Nanopores

Stability, long lifetime, resilience against clogging, low noise, and low cost are five critical cornerstones of solid-state nanopore technology. Here, a fabrication protocol is described wherein >1 million events are obtained from a single solid-state nanopore with both DNA and protein at the highest available lowpass filter (LPF, 100 kHz) of the Axopatch 200B-the highest event count mentioned in literature. Moreover, a total of ≈8.1 million events are reported in this work encompassing the two analyte classes. With the 100 kHz LPF, the temporally attenuated population is negligible while with the more ubiquitous 10 kHz, ≈91% of the events are attenuated. With DNA experiments, the pores are operational for hours (typically >7 h) while the average pore growth is merely ≈0.16 ± 0.1 nm h-1 . The current noise is exceptionally stable with traces typically showing <10 pA h-1 increase in noise. Furthermore, a real-time method to clean and revive pores clogged with analyte with the added benefit of minimal pore growth during cleaning (< 5% of the original diameter) is showcased. The enormity of the data collected herein presents a significant advancement to solid-state pore performance and will be useful for future ventures such as machine learning where large amounts of pristine data are a prerequisite.

Discovery of SNP Molecular Markers and Candidate Genes Associated with Sacbrood Virus Resistance in Apis cerana cerana Larvae by Whole-Genome Resequencing

Sacbrood virus (SBV) is a significant problem that impedes brood development in both eastern and western honeybees. Whole-genome sequencing has become an important tool in researching population genetic variations. Numerous studies have been conducted using multiple techniques to suppress SBV infection in honeybees, but the genetic markers and molecular mechanisms underlying SBV resistance have not been identified. To explore single nucleotide polymorphisms (SNPs), insertions, deletions (Indels), and genes at the DNA level related to SBV resistance, we conducted whole-genome resequencing on 90 Apis cerana cerana larvae raised in vitro and challenged with SBV. After filtering, a total of 337.47 gigabytes of clean data and 31,000,613 high-quality SNP loci were detected in three populations. We used ten databases to annotate 9359 predicted genes. By combining population differentiation index (FST) and nucleotide polymorphisms (π), we examined genome variants between resistant (R) and susceptible (S) larvae, focusing on site integrity (INT < 0.5) and minor allele frequency (MAF < 0.05). A selective sweep analysis with the top 1% and top 5% was used to identify significant regions. Two SNPs on the 15th chromosome with GenBank KZ288474.1_322717 (Guanine > Cytosine) and KZ288479.1_95621 (Cytosine > Thiamine) were found to be significantly associated with SBV resistance based on their associated allele frequencies after SNP validation. Each SNP was authenticated in 926 and 1022 samples, respectively. The enrichment and functional annotation pathways from significantly predicted genes to SBV resistance revealed immune response processes, signal transduction mechanisms, endocytosis, peroxisomes, phagosomes, and regulation of autophagy, which may be significant in SBV resistance. This study presents novel and useful SNP molecular markers that can be utilized as assisted molecular markers to select honeybees resistant to SBV for breeding and that can be used as a biocontrol technique to protect honeybees from SBV.

Enhancement of antiviral activity of egg yolk antibodies against Chinese sacbrood virus

Chinese sacbrood virus (CSBV) poses a serious threat to the apiculture of China. Although several approaches have been attempted to control CSBV infection, their applications have been greatly limited in practical breeding of honeybees due to poor effectiveness. Egg yolk antibodies (EYA) have shown a promising protection for bees against CSBV infection. This study was conducted to produce high titer EYA and then further improve their antiviral effect. Among three vaccination groups, the EYA titer in graphene oxide-chitosan group was highest (1.591 ± 0.145), in Freund's group was modest (1.195 ± 0.040), and in white oil group was lowest (1.058 ± 0.056). After three injections of each vaccine in hens, EYA were produced at the highest level with a 14-day period. After application of EYA for more than two years in actual bee breeding, prevention and treatment assays showed that EYA confered 98.9 to 100% protection from CSBV infection. The mortality of the control group reached to a range of 91.2 to 100%. This study demonstrated that the high titer EYA have been successfully prepared with significant anti-CSBV activity and that these antibodies may feasibly be used for CSBV treatment to meet the practical needs of apiculture.

Daytime rest: Association with 24-h rest-activity cycles, circadian timing and cognition in older adults

Growing epidemiological evidence points toward an association between fragmented 24-h rest-activity cycles and cognition in the aged. Alterations in the circadian timing system might at least partially account for these observations. Here, we tested whether daytime rest (DTR) is associated with changes in concomitant 24-h rest probability profiles, circadian timing and neurobehavioural outcomes in healthy older adults. Sixty-three individuals (59-82 years) underwent field actigraphy monitoring, in-lab dim light melatonin onset assessment and an extensive cognitive test battery. Actimetry recordings were used to measure DTR frequency, duration and timing and to extract 24-h rest probability profiles. As expected, increasing DTR frequency was associated not only with higher rest probabilities during the day, but also with lower rest probabilities during the night, suggesting more fragmented night-time rest. Higher DTR frequency was also associated with lower episodic memory performance. Moreover, later DTR timing went along with an advanced circadian phase as well as with an altered phase angle of entrainment between the rest-activity cycle and circadian phase. Our results suggest that different DTR characteristics, as reflective indices of wake fragmentation, are not only underlined by functional consequences on cognition, but also by circadian alteration in the aged.

Cell-free therapy based on stem cell-derived exosomes: A promising approach for wound healing

There are several successive and overlapping phases in wound healing as a complex process. By the disruption of each of thesephases, chronic non-healing wounds are resultant. Despite the present soothing surgeries, standard wound dressings, and topical gels, the wound is often not completelyclosed. Today, stem cells have attracted a huge deal of attention therapeutically and pharmaceutically considering their unique features. However, they have some restrictions. Moreover, it is hoped to eliminate the limitations of cellular therapies based on their derivatives known as exosomes. Exosomes are extracellular vesicles secreted from cells. They have a diameter of almost 30-150 nm and miRNAs, mRNAs, and proteins that are possibly different from the source cell are included in exosomal contents. Such nanovesicles have a key role in the intercellular communication of pathological and physiological procedures. Exosome-based therapy is a new significant method for wound healing. By exosomes effects, wound management may be improved and a new therapeutic model may be highlighted for cell-free therapies with reduced side effects for the wound repair. This article is protected by copyright. All rights reserved.

Comparison of the gut microbiome of sacbrood virus-resistant and -susceptible Apis cerana from South Korea

Honey bees are important pollinators for the conservation of the ecosystem and agricultural products and provide a variety of products important for human use, such as honey, pollen, and royal jelly. Sacbrood disease (SD) is a devastating viral disease in Apis cerana; an effective preventive measure for SD is urgently needed. In this study, the relationship between the gut microbiome of honey bees and SD was investigated by pyrosequencing. Results revealed that sacbrood virus (SBV)-resistant A. cerana strains harbour a unique acetic acid bacterium, Bombella intestini, and the lactic acid bacteria (LAB) Lactobacillus (unclassified)_uc, Bifidobacterium longum, B. catenulatum, Lactococcus lactis, and Leuconostoc mesenteroides in larvae and Hafnia alvei, B. indicum, and the LAB L. mellifer and Lactobacillus HM215046_s in adult bees. Changes in the gut microbiome due to SBV infection resulted in loss of bacteria that could affect host nutrients and inhibit honey bee pathogens, such as Gilliamella JFON_s, Gilliamella_uc, Pseudomonas putida, and L. kunkeei in A. cerana larvae and Frischella_uc, Pantoea agglomerans, Snodgrassella_uc, and B. asteroides in adult bees. These findings provide important information for the selection of probiotics for A. cerana larvae and adults to prevent pathogenic infections and keep honey bees healthy.

Extracellular vesicles derived from mesenchymal stem/stromal cells: The regenerative impact in liver diseases

Liver dysfunctions are classified into acute and chronic diseases, which comprise a heterogeneous group of pathological features and a high mortality rate. Liver transplantation remains the gold-standard therapy for most liver diseases, with concomitant limitations related to donor organ shortage and lifelong immunosuppressive therapy. A concept in liver therapy intends to overcome these limitations based on the secreted extracellular vesicles (EVs; microvesicles and exosomes) by mesenchymal stem/stromal cells (MSCs). A significant number of studies have shown that factors released by MSCs could induce liver repair and ameliorate systemic inflammation through paracrine effects. It is well known that this paracrine action is based not only on the secretion of cytokines and growth factors but also on EVs, which regulate pathways associated with inflammation, hepatic fibrosis, integrin-linked protein kinase signaling, and apoptosis. Herein, we extensively discuss the differential effects of MSC-EVs on different liver diseases and on cellular and animal models and address the complex molecular mechanisms involved in the therapeutic potential of EVs. In addition, we cover the crucial information regarding the type of molecules contained in MSC-EVs that can be effective in the context of liver diseases. In conclusion, outcomes on MSC-EV-mediated therapy are expected to lead to an innovative, cell-free, noninvasive, less immunogenic, and nontoxic alternative strategy for liver treatment and to provide important mechanistic information on the reparative function of liver cells.

Sacbrood viruses cross-infection between Apis cerana and Apis mellifera: Rapid detection, viral dynamics, evolution and spillover risk assessment

Recent outbreaks of sacbrood virus (SBV) have caused serious epizootic disease in Apis cerana populations across Asia including Taiwan. Earlier phylogenetic analyses showed that cross-infection of AcSBV and AmSBV in both A. cerana and A. mellifera seems common, raising a concern of cross-infection intensifying the risk of disease resurgence in A. cerana. In this study, we analyzed the dynamics of cross-infection in three different types of apiaries (A. mellifera-only, A. cerana-only and two species co-cultured apiaries) over one year in Taiwan. Using novel, genotype-specific primer sets, we showed that SBV infection status varies across apiaries: AmSBV-AM and AcSBV-AC were the major genotype in the A. mellifera-only and the A. cerana-only apiaries, respectively, while AmSBV-AC and AcSBV-AC were the dominant genotypes in the co-cultured apiaries. Interestingly, co-cultured apiaries were among the only apiary type that harbored all variants and dual infections (i.e., AC and AM genotype co-infection in a single sample), indicating the interactions between hosts may form a conduit for cross-infection. The cross-infection between the two honey bee species appears to occur in a regular cycle with temporal fluctuation of AmSBV-AC and AcSBV-AC prevalence synchronized to each other in the co-cultured apiaries. Artificial infection of AcSBV in A. mellifera workers showed the suppression of viral replication, suggesting the potential of A. mellifera serving as a AcSBV reservoir that may contribute to virus spillover. Furthermore, the survival rate of A. cerana larvae was significantly reduced after artificial infections of both SBVs, indicating fitness costs of cross-infection on A. cerana and thus a high risk of disease resurgence in co-cultured apiaries. Our field and laboratory data provide baseline information that facilitates understanding of the risk of SBV cross-infection, and highlights the urgent need of SBV monitoring in co-cultured apiaries.

Differential Viral Distribution Patterns in Reproductive Tissues of Apis mellifera and Apis cerana Drones

Honeybee drones are male bees that mate with virgin queens during the mating flight, consequently transferring their genes to offspring. Therefore, the health of drones affects the overall fitness of the offspring and ultimately the survivability of the colony. Honeybee viruses are considered to be a major threat to the health of honeybees. In the present study, we demonstrated the pattern of common honeybee viruses in various tissues of drones in the western honeybee, Apis mellifera, and the eastern honeybee, Apis cerana. Drones were collected during the mating flight and analyzed using quantitative real-time (qRT-PCR) to detect the presence of seven honeybee viruses. The qRT-PCR result revealed that three honeybee viruses, namely Black Queen Cell Virus (BQCV), Deformed Wing Virus (DWV), and Chinese Sacbrood Virus (CSBV), were detected in the reproductive tissues of A. mellifera and A. cerana drones. The results from qRT-PCR showed that the Israeli Acute Paralysis Virus (IAPV) was only detected in A. mellifera drone body tissues. Moreover, the prevalence of DWV and BQCV in the drones collected from A. mellifera colonies was significantly higher than that of A. cerana. In addition, virus multiple infections were higher in A. mellifera drones compared to those in A. cerana. CSBV was found predominantly in the reproductive tissues of A. cerana drones. This study is the first report describing the presence of the CSBV in reproductive tissues of A. mellifera drones. Our results may reflect the preference of honeybee viruses in honeybee species and may provide a piece of interesting evidence for understanding the virus transmission in A. cerana.

Up-regulated 2-alkenal reductase expression improves low-nitrogen tolerance in maize by alleviating oxidative stress

In plants, cellular lipid peroxidation is enhanced under low nitrogen (LN) stress; this increases the lipid-derived reactive carbonyl species (RCS) levels. The cellular toxicity of RCS can be reduced by various RCS-scavenging enzymes. However, the roles of these enzymes in alleviating oxidative stress and improving nutrient use efficiency (NUE) under nutrient stress remain unknown. Here, we overexpressed maize endogenous NADPH-dependent 2-alkenal reductase (ZmAER) in maize; it significantly increased the tolerance of transgenic plants (OX-AER) to LN stress. Under LN condition, the biomass, nitrogen accumulation, NUE, and leaf photosynthesis of the OX-AER plants were significantly higher than those of the wild-type (WT) plants. The leaf and root malondialdehyde and H₂ O₂ levels in the transgenic plants were significantly lower than those in WT. The expression of antioxidant enzyme-related genes ZmCAT3, ZmPOD5 and ZmPOD13 was significantly higher in the transgenic lines than in WT. Under LN stress, the nitrate reductase activity in the OX-AER leaves was significantly increased compared with that in the WT leaves. Furthermore, under LN stress, ZmNRT1.1 and ZmNRT2.5 expression was upregulated in the OX-AER plants compared with that in WT. Overall, up-regulated ZmAER expression could enhance maize's tolerance to LN stress by alleviating oxidative stress and improve NUE.

Genomic Sequencing and Comparison of Sacbrood Viruses from Apis cerana and Apis mellifera in Taiwan

Sacbrood virus (SBV) was the first identified bee virus and shown to cause serious epizootic infections in the population of Apis cerana in Taiwan in 2015. Herein, the whole genome sequences of SBVs in A. cerana and A. mellifera were decoded and designated AcSBV-TW and AmSBV-TW, respectively. The whole genomes of AcSBV-TW and AmSBV-TW were 8776 and 8885 bp, respectively, and shared 90% identity. Each viral genome encoded a polyprotein, which consisted of 2841 aa in AcSBV-TW and 2859 aa in AmSBV-TW, and these sequences shared 95% identity. Compared to 54 other SBVs, the structural protein and protease regions showed high variation, while the helicase was the most highly conserved region among SBVs. Moreover, a 17-amino-acid deletion was found in viral protein 1 (VP1) region of AcSBV-TW compared to AmSBV-TW. The phylogenetic analysis based on the polyprotein sequences and partial VP1 region indicated that AcSBV-TW was grouped into the SBV clade with the AC-genotype (17-aa deletion) and was closely related to AmSBV-SDLY and CSBV-FZ, while AmSBV-TW was grouped into the AM-genotype clade but branched independently from other AmSBVs, indicating that the divergent genomic characteristics of AmSBV-TW might be a consequence of geographic distance driving evolution, and AcSBV-TW was closely related to CSBV-FZ, which originated from China. This 17-amino-acid deletion could be found in either AcSBV or AmSBV in Taiwan, indicating cross-infection between the two viruses. Our data revealed geographic and host specificities between SBVs. The amino acid difference in the VP1 region might serve as a molecular marker for describing SBV cross-infection.

Identification of Immune Response to Sacbrood Virus Infection in Apis cerana Under Natural Condition

Chinese sacbrood virus (CSBV) is a serious threat to eastern honeybees (Apis cerana), especially larvae. However, the pathological mechanism of this deadly disease remains unclear. Here, we employed mRNA and small RNA (sRNA) transcriptome approach to investigate the microRNAs (miRNAs) and small interfering RNAs (siRNAs) expression changes of A. cerana larvae infected with CSBV under natural condition. We found that serine proteases involved in immune response were down-regulated, while the expression of siRNAs targeted to serine proteases were up-regulated. In addition, CSBV infection also affected the expression of larvae cuticle proteins such as larval cuticle proteins A1A and A3A, resulting in increased susceptibility to CSBV infection. Together, our results provide insights into sRNAs that they are likely to be involved in regulating honeybee immune response.

Visualizing Sacbrood Virus of Honey Bees via Transformation and Coupling with Enhanced Green Fluorescent Protein

Sacbrood virus (SBV) of honey bees is a picornavirus in the genus Iflavirus. Given its relatively small and simple genome structure, single positive-strand RNA with only one ORF, cloning the full genomic sequence is not difficult. However, adding nonsynonymous mutations to the bee iflavirus clone is difficult because of the lack of information about the viral protein processes. Furthermore, the addition of a reporter gene to the clones has never been accomplished. In preliminary trials, we found that the site between 3′ untranslated region (UTR) and poly(A) can retain added sequences. We added enhanced green fluorescent protein (EGFP) expression at this site, creating a SBV clone with an expression tag that does not affect virus genes. An intergenic region internal ribosome entry site (IRES) from Black queen cell virus (BQCV) was inserted to initiate EGFP expression. The SBV-IRES-EGFP clone successfully infected Apis cerana and Apis mellifera, and in A. cerana larvae, it was isolated and passaged using oral inoculation. The inoculated larvae had higher mortality and the dead larvae showed sacbrood symptoms. The added IRES-EGFP remained in the clone through multiple passages and expressed the expected EGFP in all infected bees. We demonstrated the ability to add gene sequences in the site between 3′-UTR and poly(A) in SBV and the potential to do so in other bee iflaviruses; however, further investigations of the mechanisms are needed. A clone with a desired protein expression reporter will be a valuable tool in bee virus studies.

Tomato GLR3.3 and GLR3.5 mediate cold acclimation-induced chilling tolerance by regulating apoplastic H2 O2 production and redox homeostasis

Plant glutamate receptor-like (GLR) genes play important roles in plant development and immune response. However, the functions of GLRs in abiotic stress response remain unclear. Here we show that cold acclimation at 12°C induced the transcripts of GLR3.3 and GLR3.5 with increased tolerance against a subsequent chilling at 4 °C. Silencing of GLR3.3 or/and GLR3.5 or application of the antagonist of ionotropic glutamate receptor 6,7-dinitroquinoxaline-2,3-dione (DNQX), all compromised the acclimation-induced increases in the transcripts of respiratory burst oxidase homolog1 (RBOH1), activity of NADPH oxidase, the accumulation of apoplastic H₂ O₂ and the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG), resulting in an attenuated chilling tolerance; the effect, however, was rescued by foliar application of H₂ O₂ or GSH. Both RBOH1-silenced and glutathione biosynthesis genes, γ- glutamylcysteine synthetase (GSH1)- and glutathione synthetase (GSH2)-cosilenced plants had decreased chilling tolerance with reduced GSH/GSSG ratio. Moreover, application of DNQX had little effects on the GSH/GSSG ratio and the tolerance in RBOH1-silenced plants and GSH1- and GSH2-cosilenced plants. These findings unmasked the functional hierarchy of GLR-H₂ O₂ -glutathione cascade and shed new light on cold response pathway in tomato plants.

Genetic and phylogenetic analysis of Chinese sacbrood virus isolates from Apis mellifera

Background

Sacbrood virus (SBV) is one of the most pathogenic honeybee viruses that exhibits host specificity and regional variations. The SBV strains that infect the Chinese honeybee Apis cerana are called Chinese SBVs (CSBVs).

Methods

In this study, a CSBV strain named AmCSBV-SDLY-2016 (GenBank accession No. MG733283) infecting A. mellifera was identified by electron microscopy, its protein composition was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and agar gel immunodiffusion assay, and its nucleotide sequence was identified using a series of reverse-transcription polymerase chain reaction fragments of AmCSBV-SDLY-2016 generated using SBV/CSBV-specific primers. To investigate phylogenetic relationships of the CSBV isolates, a phylogenetic tree of the complete open reading frames (ORF) of the CSBV sequences was constructed using MEGA 6.0; then, the similarity and recombination events among the isolated CSBV strains were analyzed using SimPlot and RDP4 software, respectively.

Results

Sequencing results revealed the complete 8,794-nucleotide long complete genomic RNA of the strain, with a single large ORF (189–8,717) encoding 2,843 amino acids. Comparison of the deduced amino acid sequence with the SBV/CSBV reference sequences deposited in the GenBank database identified helicase, protease, and RNA-dependent RNA polymerase domains; the structural genes were located at the 5′ end, whereas the non-structural genes were found at the 3′ end. Multiple sequence alignment showed that AmCSBV-SDLY-2016 had a 17-amino acid (aa) and a single aa deletion at positions 711–729 and 2,128, respectively, as compared with CSBV-GD-2002, and a 16-aa deletion (positions 711–713 and 715–728) as compared with AmSBV-UK-2000. However, AmCSBV-SDLY-2016 was similar to the CSBV-JLCBS-2014 strain, which infects A. cerana. AmCSBV-SDLY-2016 ORF shared 92.4–97.1% identity with the genomes of other CSBV strains (94.5–97.7% identity for deduced amino acids). AmCSBV-SDLY-2016 was least similar (89.5–90.4% identity) to other SBVs but showed maximum similarity with the previously reported CSBV-FZ-2014 strain. The phylogenetic tree constructed from AmCSBV-SDLY-2016 and 43 previously reported SBV/CSBV sequences indicated that SBV/CSBV strains clustered according to the host species and country of origin; AmCSBV-SDLY-2016 clustered with other previously reported Chinese and Asian strains (AC genotype SBV, as these strains originated from A. cerana) but was separate from the SBV genomes originating from Europe (AM genotype SBV, originating from A. mellifera). A SimPlot graph of SBV genomes confirmed the high variability, especially between the AC genotype SBV and AM genotype SBV. This genomic diversity may reflect the adaptation of SBV to specific hosts, ability of CSBV to cross the species barrier, and the spatial distances that separate CSBVs from other SBVs.

The aryl hydrocarbon receptor (AhR) as a breast cancer drug target

Breast cancer is the most common cancer in women, with more than 1.7 million diagnoses worldwide per annum. Metastatic breast cancer remains incurable, and the presence of triple-negative phenotypes makes targeted treatment impossible. The aryl hydrocarbon receptor (AhR), most commonly associated with the metabolism of xenobiotic ligands, has emerged as a promising biological target for the treatment of this deadly disease. Ligands for the AhR can be classed as exogenous or endogenous and may have agonistic or antagonistic activity. It has been well reported that agonistic ligands may have potent and selective growth inhibition activity in a number of oncogenic cell lines, and one (aminoflavone) has progressed to phase I clinical trials for breast cancer sufferers. In this study, we examine the current state of the literature in this area and elucidate the promising advances that are being made in hijacking the cytosolic-to-nuclear pathway of the AhR for the possible future treatment of breast cancer.

Identification of the Novel Host Protein Interacting With the Structural Protein VP1 of Chinese Sacbrood Virus by Yeast Two-Hybrid Screening

Chinese sacbrood virus (CSBV) is the major cause and lead to the collapse of Apis cerana colonies. VP1, the structural protein of CSBV, shows the highest variation in the amino acid sequences among proteins from different CSBV strains as well as exhibits excellent immunogenicity. However, its function with host protein still remains unclear. To clarify its function with host protein, we screened out host cellular proteins that interact with VP1 using the membrane protein yeast two-hybrid system. In addition, we verified interactions between heat shock protein 70 cognate 5 (Hsp70-c5) and VP1 using glutathione S-transferase (GST) pull-down and co-immunoprecipitation assays. VP1 and Hsp70-c5 were colocalized in the cytoplasm and nucleus. Using western blot and real-time polymerase chain reaction (PCR), Hsp70-c5 expression in CSBV-infected larvae was upregulated compared with that in healthy larvae. We observed that when we silenced Hsp70-c5, VP1 expression was significantly downregulated. These results demonstrate that Hsp70-c5 is involved in at least one stage(s) of the viral life cycle.

Prevalence of bee viruses in Apis cerana cerana populations from different locations in the Fujian Province of China

Prevalence of honeybee viral diseases has recently been causing major problems in the beekeeping industry, causing economic losses worldwide. Honeybees are susceptible to a variety of diseases and various pathogens. Among these pathogens, prevalence viruses, along with other factors, are seriously threatening the health of bee species. In the present study, samples were collected from 80 Apis cerana cerana (A. c. cerana) colonies from three different locations, Cangshan, Fuan, and Yongtai, in the Fujian Province of China. All samples were screened using the reverse transcription polymerase chain reaction (RT-PCR) method for detection of seven honeybee viruses, namely, Chinese sacbrood virus (CSBV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), acute bee paralysis virus (ABPV), and Kashmir bee virus (KBV). Our results showed that CSBV was the most prevalent as it was detected in (90%), of the samples, DWV was detected in (81.25%), and IAPV was detected in (26.25%). In contrast, insignificant prevalence results were obtained from all apiaries for BQCV, CBPV, APBV, and KBV, which were not detected in any sample. Here, we are providing the first report on the molecular detection of honeybee viruses, especially the prevalence of IAPV, from different regions in the Fujian Province of China with a high prevalence of bee viruses, on A. c. cerana, and there is great concern for the presence of honeybee viruses in the population of the native honeybee (A. c. cerana) in China.

Phylogenetic and recombination analyses of two deformed wing virus strains from different honeybee species in China

Background

Deformed wing virus (DWV) is one of many viruses that infect honeybees and has been extensively studied because of its close association with honeybee colony collapse that is induced by Varroa destructor. However, virus genotypes, sequence characteristics, and genetic variations of DWV remain unknown in China.

Methods

Two DWV strains were isolated from Jinzhou and Qinhuangdao cities in China, and were named China1-2017 (accession number: MF770715) and China2-2018 (accession number: MH165180), respectively, and their complete genome sequences were analyzed. To investigate the phylogenetic relationships of the DWV isolates, a phylogenetic tree of the complete open reading frame (ORF), structural protein VP1, and non-structural protein 3C+RdRp of the DWV sequences was constructed using the MEGA 5.0 software program. Then, the similarity and recombinant events of the DWV isolated strains were analyzed using recombination detection program (RDP4) software and genetic algorithm for recombination detection (GARD).

Results

The complete genomic analysis showed that the genomes of the China1-2017 and China2-2018 DWV strains consisted of 10,141 base pairs (bp) and 10,105 bp, respectively, and contained a single, large ORF (China1-2017: 1,146–9,827 bp; China2-2018: 1,351–9,816 bp) that encoded 2,894 amino acids. The sequences were compared with 20 previously reported DWV sequences from different countries and with sequences of two closely related viruses, Kakugo virus (KV) and V. destructor virus-1. Multiple sequence comparisons revealed a nucleotide identity of 84.3–96.7%, and identity of 94.7–98.6% in amino acids between the two isolate strains and 20 reference strains. The two novel isolates showed 96.7% nucleotide identity and 98.1% amino acid identity. The phylogenetic analyses showed that the two isolates belonged to DWV Type A and were closely related to the KV-2001 strain from Japan. Based on the RDP4 and GARD analyses, the recombination of the China2-2018 strain was located at the 4,266–7,507 nt region, with Korea I-2012 as an infer unknown parent and China-2017 as a minor parent, which spanned the entire helicase ORF. To the best of our knowledge, this is the first study to the complete sequence of DWV isolated from Apis cerana and the possible DWV recombination events in China. Our findings are important for further research of the phylogenetic relationship of DWVs in China with DWV strains from other countries and also contribute to the understanding of virological properties of these complex DWV recombinants.

Preparation and Application of Egg Yolk Antibodies Against Chinese Sacbrood Virus Infection

Chinese sacbrood virus (CSBV) infects Apis cerana larvae, resulting in the inability of the larvae to pupate and their consequent death, which may pose a serious threat to entire colonies. As there is no effective medical treatment for CSBV infections, further studies are necessary. In this study, an effective treatment for CSBV is described, based on a specific immunoglobulin Y (IgY) from egg yolk against CSBV. The inactivated vaccine was produced by ultracentrifugation and formalin treatment, using CSBV purified from a natural outbreak. The specific IgY was produced by immunization of white leghorn hens with the vaccine. An enzyme-linked immunosorbent assay using purified CSBV as the coating antigen revealed that the anti-CSBV IgY titer began increasing in the egg yolk on the 14th day post-immunization, reaching a peak on day 42, and anti-CSBV IgY remained at a high level until day 91. IgY isolated from the combinations of egg yolk collected between days 42-91 was purified by PEG and ammonium sulfate precipitation. In three repeated protection experiments using A. cerana larvae inoculated with CSBV, the survival rate of larvae was more than 80%, and the titer of anti-CSBV IgY was more than 25 and 24 when the larvae were fed IgY 24 h after and before inoculation with CSBV, respectively. Therefore, 400 colonies infected with CSBV were treated by feeding sugar containing IgY solutions with an antibody titer of 25, and the cure rate was 95-100%. Three hundred susceptible colonies were protected by feeding the larvae with sugar containing IgY solutions with an antibody titer of 24, and the protection rate was 97%. The results clearly suggest that a specific IgY was obtained from hens immunized with an inactivated-CSBV vaccine; this may be a novel method for controlling CSBV infection.

The role of enhancer of zeste homolog 2: From viral epigenetics to the carcinogenesis of hepatocellular carcinoma

Nowadays, epigenetics covers a crucial role in different fields of science. The enhancer of zeste homolog 2 (EZH2), the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2), is a big proponent of how epigenetic changes can affect the initiation and progression of several diseases. Through its catalytic activity, responsible for the tri-methylation of lysine 27 of the histone H3 (H3K27me3), EZH2 is a good target for both diagnosis and therapy of different pathologies. A large number of studies have demonstrated its crucial role in cancer initiation and progression. Nevertheless, only recently its function in virus diseases has been uncovered; therefore, EZH2 can be an important promoter of viral carcinogenesis. This review explores the role of EZH2 in viral epigenetics based on recent progress that demonstrated the role of this protein in virus environment. In particular, the review focuses on EZH2 behavior in Hepatitis B Virus, analyzing its role in the rise of Hepatocellular Carcinoma.

Screening of binding proteins that interact with Chinese sacbrood virus VP3 capsid protein in Apis cerana larvae cDNA library by the yeast two-hybrid method

Chinese sacbrood virus (CSBV) causes larval death and apiary collapse of Apis cerana. VP3 is a capsid protein of CSBV but its function is poorly understood. To determine the function of VP3 and screen for novel binding proteins that interact with VP3, we conducted yeast two-hybrid screening, glutathione S-transferase pull-down, and co-immunoprecipitation assays. Galectin (GAL) is a protein involved in immune regulation and host-pathogen interactions. The yeast two-hybrid screen implicated GAL as a major VP3-binding candidate. The assays showed that the VP3 interacted with GAL. Identification of these cellular targets and clarifying their contributions to the host-pathogen interaction may be useful for the development of novel therapeutic and prevention strategies against CSBV infection.