Protocatechuic acid, a new active substance against the challenge of avian infectious bursal disease virus

Selenium Broussonetia papyrifera polysaccharide alleviated cyclophosphamide-induced immune suppression, growth inhibition, intestinal damage, and gut microbiota disorder in yellow-feather broilers

This study aims to investigate the effects of selenium Broussonetia papyrifera polysaccharide (Se-BPP) on growth performance, immune regulation, intestinal barrier function, and gut microbiota in cyclophosphamide (CTX)-induced immunosuppressed chicks. A total of 120 one-day-old male yellow-feathered broilers were randomly divided into five groups: normal control group (NC), model control group (MC), low-dose Se-BPP group (Se-L), high-dose Se-BPP group (Se-H), and Astragalus polysaccharide (APS) group The Se-L and Se-H groups were supplemented with 0.1 % or 0.2 % Se-BPP, respectively, while the APS group was supplemented with 0.2 % APS. On days 22, 24, and 26, the NC group received intramuscular injections of 80 mg/kg saline, while the other groups received the same dose of CTX to induce immunosuppression in the chicks. The results showed that CTX caused growth retardation, immunosuppression, intestinal damage, and alterations in gut microbiota structure. Supplementation with Se-BPP improved average daily gain and reduced feed-to-gain ratio, promoting growth in immunosuppressed chicks. Se-BPP increased the immune organ index and serum content of IgG, IgM, IgA, SOD, GSH-Px, CAT, IL-2, IL-4, IL-6, IL-10, and INF-γ, thus alleviating the immunosuppression and oxidative stress caused by CTX. Additionally, Se-BPP enhanced the mRNA expression levels of ZO-1, Claudin 1, and MUC2 and increased villus height in the jejunum, effectively mitigating intestinal damage induced by CTX. Although the effect of Se-BPP on alpha diversity of the gut microbiota was not significant, it increased the abundance of beneficial bacteria such as Ruminococcus and Lactobacillus. In brief, this study demonstrated that adding Se-BPP to the diet could improve immunosuppression, intestinal damage, and microbiota disturbances in yellow-feather broiler chickens challenged with CTX, enhancing their production performance.

Xanthohumol and echinocystic acid induces PSTVd tolerance in tomato

Tomato is a popular vegetable worldwide; its production is highly threatened by infection with the potato spindle tuber viroid (PSTVd). We obtained the full-length genome sequence of previously conserved PSTVd and inoculated it on four genotypes of semi-cultivated tomatoes selected from a local tomato germplasm resource. SC-5, which is a PSTVd-resistant genotype, and SC-96, which is a PSTVd-sensitive genotype, were identified by detecting the fruit yield, plant growth, biomass accumulation, physiological indices, and PSTVd genome titer after PSTVd inoculation. A non-target metabolomics study was conducted on PSTVd-infected and control SC-5 to identify potential anti-PSTVd metabolites. The platform of liquid chromatography-mass spectrometry detected 158 or 123 differential regulated metabolites in modes of positive ion or negative ion. Principal component analysis revealed a clear separation of the global metabolite profile between PSTVd-infected leaves and control regardless of the detection mode. The potential anti-PSTVd compounds, xanthohumol, oxalicine B, indole-3-carbinol, and rosmarinic acid were significantly upregulated in positive ion mode, whereas echinocystic acid, chlorogenic acid, and 5-acetylsalicylic acid were upregulated in negative ion mode. Xanthohumol and echinocystic acid were detected as the most upregulated metabolites and were exogenously applied on PSTVd-diseased SC-96 seedlings. Both xanthohumol and echinocystic acid had instant and long-term inhibition effect on PSTVd titer. The highest reduction of disease symptom was induced by 2.6 mg/L of xanthohumol and 2.0 mg/L of echinocystic acid after 10 days of leaf spraying, respectively. A superior effect was seen on echinocystic acid than on xanthohumol. Our study provides a statistical basis for breeding anti-viroid tomato genotypes and creating plant-originating chemical preparations to prevent viroid disease.

Novel phytochemical inhibitors targeting monkeypox virus thymidine and serine/threonine kinase: integrating computational modeling and molecular dynamics simulation

Due to the rapid spread of the monkeypox virus and rise in the number of cases, there is an urgent need for the development of effective drugs against the infection. Serine/threonine protein kinase (Ser/Thr kinase) and Thymidine Kinase (TK) plays an imperative role in the replication and virulence of monkeypox virus and thus is deliberated as an attractive target in anti-viral drug development. In the present study, the 3D structure of monkeypox virus Ser/Thr kinase and TK was generated via molecular modeling techniques and performed their thorough structural analysis. We have screened potent anti-viral phytochemicals from the literature to inhibit Ser/Thr kinase and TK. As part of the initial screening, the physicochemical properties of the compounds were examined. Following this, a structure-based molecular docking technique was used to select compounds based on their binding affinity towards Ser/Thr kinase and TK. In order to find more potent hits against Ser/Thr kinase and TK, further examinations of ADMET properties, PAINS patterns and blood-brain barrier permeability were conducted. As a result, thalimonine and galanthamine were identified from the screening process bearing appreciable binding affinity towards Ser/Thr kinase and TK respectively, which showed a worthy set of drug-like properties. In the end, molecular dynamics simulations were performed for 100 ns, which showed decent stability of both protein-ligand complex throughout the trajectory. Due to the possibility that both monkeypox virus target proteins may be inhibited by thalimonine and galanthamine, our study highlights the need to investigate in vivo effects of thalimonine and galanthamine.Communicated by Ramaswamy H. Sarma.

Potential Role of Protocatechuic Acid as Natural Feed Additives in Farm Animal Production

Restriction on using antibiotics in animal feed that generates demand for antibiotics alternatives in animal breeding. Providing safe food to humans free from the residual effects of antibiotics is a great challenge to animal producers and food-producing industry owners. Medicinal plants and their extracts as feed supplements have been used to promote the growth and health of farm animals for centuries. Protocatechuic acid (PCA) is a phenolic compound that originated from natural plants. For years, the health-promoting role of PCA has been becoming an attraction of research in nutrition and pharmacy. Thus, it can be used as an active natural feed additive while synthetic antibiotics are illegal to use in animal breeding. However, the practical application of PCA in view of dosages in animal nutrition, together with its mode of action on animal health, is not well known. In this regard, this review study has explored the mode of action of PCA and the feasibility of using those compounds in animal nutrition. This review study concludes that phenolic-rich protocatechuic acid as a natural feed additive may be useful in enhancing antioxidant status, immune function, antimicrobial, intestinal health and growth performance of farm animals.

Molecular docking of secondary metabolites from Indonesian marine and terrestrial organisms targeting SARS-CoV-2 ACE-2, M pro, and PL pro receptors

With the uncontrolled spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), development and distribution of antiviral drugs and vaccines have gained tremendous importance. This study focused on two viral proteases namely main protease (Mpro) and papain-like protease (PLpro) and human angiotensin-converting enzyme (ACE-2) to identify which of these are essential for viral replication. We screened 102 secondary metabolites against SARS-CoV-2 isolated from 36 terrestrial plants and 36 marine organisms from Indonesian biodiversity. These organisms are typically presumed to have antiviral effects, and some of them have been used as an immunomodulatory activity in traditional medicine. For the molecular docking procedure to obtain Gibbs free energy value (∆G), toxicity, ADME and Lipinski, AutoDock Vina was used. In this study, five secondary metabolites, namely corilagin, dieckol, phlorofucofuroeckol A, proanthocyanidins, and isovitexin, were found to inhibit ACE-2, Mpro, and PLpro receptors in SARS-CoV-2, with a high affinity to the same sites of ptilidepsin, remdesivir, and chloroquine as the control molecules. This study was delimited to molecular docking without any validation by simulations concerned with molecular dynamics. The interactions with two viral proteases and human ACE-2 may play a key role in developing antiviral drugs for five active compounds. In future, we intend to investigate antiviral drugs and the mechanisms of action by in vitro study.

Very virulent infectious bursal disease virus-induced immune injury is involved in inflammation, apoptosis, and inflammatory cytokines imbalance in the bursa of fabricius

Infectious bursal disease virus (IBDV) can cause a highly contagious disease in young chickens, resulting in bursal necrosis that causes severe damage to the immune system. The effects of various IBDV strains on the bursa of Fabricius (BF) have been extensively studied; however, few studies have investigated the effects of IBDV strain LJ-5, a newly discovered very virulent IBDV (vvIBDV), infection on young chicken BF. In this study, three-week-old specific pathogen-free (SPF) chickens were infected with vvIBDV for one to five days. LJ-5 decreased the bursa index, B lymphocyte viability and immunoglobulin (Ig) levels, including IgM and IgA in the bursa and IgY in the sera. Histopathological analysis revealed necrosis and depletion of the lymphoid cells and complete loss of bursal architecture in the BF, and transmission electron microscopy revealed mitochondrial vacuoles, cristae breaks, and nuclear damage in vvIBDV-infected bursa tissue. The number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling-positive nuclei significantly increased following IBDV infection. Cytokine levels increased in the bursa after IBDV infection, promoting inflammation and causing an inflammatory imbalance. Apoptotic gene expression confirmed that vvIBDV infection promotes the apoptosis of bursal cells. These results suggest that vvIBDV infection attenuate immune responses by reducing B lymphocyte activity of secretion Ig in the bursa or sera and triggers inflammation, apoptosis, and an imbalance of inflammatory cytokines in the BF, resulting in immune injury in SPF chickens, which offered basic data for further study of vvIBDV pathogenesis.

Genome-wide analysis of differentially expressed mRNAs, lncRNAs, and circRNAs in chicken bursae of Fabricius during infection with very virulent infectious bursal disease virus

Background

Infectious bursal disease virus (IBDV) causes acute, highly contagious, immunosuppressive, and lethal infectious disease in young chickens and mainly infects the bursa of Fabricius (BF). To investigate interactions between IBDV and its host, RNA sequencing was applied to analyze the responses of the differentially expressed transcriptional profiles of BF infected by very virulent IBDV (vvIBDV).

Results

In total, 317 upregulated and 94 downregulated mRNAs were found to be significantly differentially expressed in infected chickens, compared to controls. Long non-coding RNA (lncRNA) and circular RNA (circRNA) alterations were identified in IBDV-infected chickens, and significantly different expression was observed in 272 lncRNAs and 143 circRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed to assess the functions of significantly dysregulated genes, which showed that the JAK-STAT signaling pathway, the NOD-like receptor signaling pathway, and apoptosis may be activated by IBDV infection. We predicted interactions between differentially expressed genes and produced lncRNA-mRNA and circRNA-miRNA-mRNA regulator network.

Conclusions

The present study identified the expression profiles of mRNAs, lncRNAs, and circRNAs during vvIBDV infection and provides new insights into the pathogenesis of IBDV and antiviral immunity of the host.

Anti-feline immunodeficiency virus reverse transcriptase properties of some medicinal and edible mushrooms

Background and Aim

Feline immunodeficiency virus (FIV) causes AIDS-like symptoms in domestic and wild cats. Treatment of infected cats has been performed using human anti-HIV drugs, which showed some limitations. This study aimed to determine the anti-FIV potential of some mushrooms.

Materials and Methods

A total of 17 medicinal and edible mushrooms were screened to find their inhibitory effect against FIV reverse transcriptase (FIV-RT). Three solvents, water, ethanol, and hexane, were used to prepare crude mushroom extracts. Fluorescence spectroscopy was used to perform relative inhibition and 50% inhibitory concentrations (IC₅₀) studies.

Results

The ethanol extract from dried fruiting bodies of Inonotus obliquus showed the strongest inhibition with an IC₅₀ value of 0.80±0.16 μg/mL. The hexane extract from dried mycelium of I. obliquus and ethanol and water extracts from fresh fruit bodies of Phellinus igniarius also exhibited strong activities with the IC₅₀ values of 1.22±0.20, 4.33±0.39, and 6.24±1.42 μg/mL, respectively. The ethanol extract from fresh fruiting bodies of Cordyceps sinensis, hexane extracts from dried mycelium of I. obliquus, ethanol extracts of Ganoderma lucidum, hexane extracts of fresh fruiting bodies of Morchella esculenta, and fresh fruiting bodies of C. sinensis showed moderate anti-FIV-RT activities with IC₅₀ values of 29.73±12.39, 49.97±11.86, 65.37±14.14, 77.59±8.31, and 81.41±17.10 μg/mL, respectively. These mushroom extracts show anti-FIV potential.

Conclusion

The extracts from I. obliquus, P. igniarius, C. sinensis, and M. esculenta showed potential anti-FIV activity.

A step forward in the development ofin situproduct recovery by reactive separation of protocatechuic acid

A conceptual design of an ISPR configuration for the biosynthesis, separation, and recovery of PCA by reactive extraction with TBP in natural non-toxic diluents.

Pro-apoptosis effects of protocatechuic acid in the early stage of infectious bursal disease virus infection

Infectious bursal disease virus (IBDV) is a very important small RNA virus in the family of Birnaviridae, which can cause severe immunosuppressive effects and pathological damages in young chickens. It can replicate in bursal lymphocytes and impede the growth and development of B cells, finally causing bursal lymphocytes apoptosis. Previous results have shown that protocatechuic acid (PCA) as an important phenolic compound could effectively improve the survival rate of chickens infected with IBDV. The current study aimed to explore how PCA influenced the pathogenesis of IBDV, especially lymphocyte apoptosis in the process of IBDV infection. The results showed that PCA could effectively alleviate bursal pathological changes at the early stage of IBDV invasion. Moreover, bursal lymphocyte apoptosis for tissue section samples was largely elevated by PCA by using the terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) method while the bursal lymphocyte apoptosis ratio was also increased by PCA by flow cytometry in the early stage of IBDV infection in vivo. Meanwhile, PCA could promote non-lymphocyte apoptosis in vitro. Further study displayed that the potential mechanisms mainly relied on regulation of the expressions of pro-apoptotic protein Bax and anti-apoptotic Bcl-2, thus speeding up the process of IBDV-infected cell apoptosis and preventing virus infection. Meanwhile, the results displayed that the PI3K/Akt and NF kappa B signal pathways might play an important role in promoting cell apoptosis after IBDV infection. Overall, PCA as a potent antiviral drug precursor is expected to be applied in the poultry industry as a substitute for clinical antiviral application.

Protocatechuic acid (PCA) induced a better antiviral effect by immune enhancement in SPF chickens

Protocatechuic acid (PCA) is an antiviral agent against Avian Influenza virus (AIV) and Infectious Bursal Disease (IBD) virus, but its antiviral mechanism is unknown. In this study, we evaluated the humoral and cellular responses to PCA in specific pathogen-free (SPF) chickens. One hundred forty 35-day-old SPF chickens were randomly divided into 7 groups. The birds were inoculated with the commercial, attenuated Newcastle Disease Virus (NDV) vaccine and then received orally with 10, 20 or 40 mg/kg body weight of PCA for 30 days. Immune organ indexes, anti-Newcastle Disease Virus (NDV) antibodies and lymphocyte proliferation, but not body weight, were significantly increased in chicken treated with 40 mg/kg PCA, compared to the control birds treated with Astragalus polysaccharide (ASP). Survival rate was 70% and 60%, respectively, in the chickens with 40 mg/kg PCA, 20 mg/kg PCA while 50% survival was found in the birds treated with 125 mg/kg ASP. PCA treatment resulted in significantly lower viral load and reduced shedding. These results indicate that PCA may improve poultry health by enhancing both the humoral and cellular immune response.

Co-infection of Chlamydia psittaci with H9N2, ORT and Aspergillus fumigatus contributes to severe pneumonia and high mortality in SPF chickens

Since 2007, most areas of China have seen outbreaks of poultry airsacculitis, which causes hugely economic losses to the poultry industry. However, there are no effective measures to combat the problem. In this study, 105 rations were collected to isolate Aspergillus spp. from the diseased farms. In subsequent experiments, SPF chickens were inoculated with Ornithobacterium rhinotracheale (ORT), Chlamydia psittaci (C. psittaci) and Aspergillus fumigatus (A. fumigatus), and mortality rate, body weight gain and lesion score were evaluated. Of these ration samples, 63 (60.0%) were A. fumigates, 21 (20.0%) were Aspergillus niger (A. niger) and 11 (10.5%) were Aspergillus candidus (A. candidus). Furthermore, SPF birds infected with C. psittaci, ORT, H9N2 virus and A. fumigatus conidia exhibited a mortality rate of 40%, while simultaneous co-infection with C. psittaci, ORT and A. fumigatus resulted in a mortality rate of 20%. The avian airsacculitis was manifested in the C. psittaci + ORT/A. fumigatus, C. psittaci + H9N2 + ORT/A. fumigatus and C. psittaci + H9N2/A. fumigatus groups while others had transient respiratory diseases without mortality. Our survey indicates that feed-borne A. fumigatus is prevalent in poultry rations. The combination of C. psittaci, ORT, H9N2 and A. fumigatus conidia contributes to the replication of avian airsacculitis by aggravating the severe damage to the air sacs and lungs of chickens.

Transcription profiles of the responses of chicken bursae of Fabricius to IBDV in different timing phases

Background

Infectious bursal disease virus (IBDV) infection causes immunosuppression in chickens and increases their susceptibility to secondary infections. To explore the interaction between host and IBDV, RNA-Seq was applied to analyse the transcriptional profiles of the responses of chickens’ bursas of Fabricius in the early stage of IBDV infection.

Results

The results displayed that a total of 15546 genes were identified in the chicken bursa libraries. Among the annotated genes, there were 2006 and 4668 differentially expressed genes in the infection group compared with the mock group on day 1 and day 3 post inoculation (1 and 3 dpi), respectively. Moreover, there were 676 common up-regulated and 83 common down-regulated genes in the bursae taken from the chickens infected with IBDV on both 1 and 3 dpi. Meanwhile, there were also some characteristic differentially expressed genes on 1 and 3 dpi. On day 1 after inoculation with IBDV, host responses mainly displayed immune response processes, while metabolic pathways played an important role on day three post infection. Six genes were confirmed by quantitative reverse transcription-PCR.

Conclusions

In conclusion, the differential gene expression profile demonstrated with RNA-Seq might offer a better understanding of the molecular interactions between host and IBDV during the early stage of infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-017-0757-x) contains supplementary material, which is available to authorized users.

Chemokine receptor CCR5 and CXCR4 might influence virus replication during IBDV infection

Both CCR5 and CXCR4 are important chemokine receptors and take vital role in migration, development and distribution of T cells, however, whether they will influence the process of T cell infiltration into bursa of Fabricius during infectious bursal disease virus (IBDV) infection is unclear. In the current study, CCR5 and CXCR4 antagonists, Maraviroc and AMD3100, were administrated into chickens inoculated with IBDV, and the gene levels of IBDV VP2, CCR5, CXCR4 and related cytokines were determined by real-time PCR. The results showed that large number of T cells began to migrate into the bursae on Day 3 post infection with IBDV and the mRNA of chemokine receptors CCR5 and CXCR4 began to increase on Day 1. Moreover, antagonist treatments have increased the VP2, CCR5 and CXCR4 gene transcriptions and influenced on the gene levels of IL-2, IL-6, IL-8, IFN-γ, TGF-β4, MHC-I and MDA5. In conclusion, the chemokine receptors CCR5 and CXCR4 might influence virus replication during IBDV infection and further study would focus on the interaction between chemokine receptors and their ligands.

Chlamydia psittaci infection increases mortality of avian influenza virus H9N2 by suppressing host immune response

Avian influenza virus subtype H9N2 (H9N2) and Chlamydia psittaci (C. psittaci) are frequently isolated in chickens with respiratory disease. However, their roles in co-infection remain unclear. We tested the hypothesis that C. psittaci enhances H9N2 infection through suppression of host immunity. Thus, 10-day-old SPF chickens were inoculated intra-tracheally with a high or low virulence C. psittaci strain, and were simultaneously vaccinated against Newcastle disease virus (NDV). Significant decreases in body weight, NDV antibodies and immune organ indices occurred in birds with the virulent C. psittaci infection, while the ratio of CD4+/CD8+ T cells increased significantly compared to that of the lower virulence strain. A second group of birds were inoculated with C. psittaci and H9N2 simultaneously (C. psittaci+H9N2), C. psittaci 3 days prior to H9N2 (C. psittaci/H9N2), or 3 days after H9N2 (H9N2/C. psittaci), C. psittaci or H9N2 alone. Survival rates were 65%, 80% and 90% in the C. psittaci/H9N2, C. psittaci+H9N2 and H9N2/C. psittaci groups, respectively and respiratory clinical signs, lower expression of pro-inflammatory cytokines and higher pathogen loads were found in both C. psittaci/H9N2 and C. psittaci+H9N2 groups. Hence, virulent C. psittaci infection suppresses immune response by inhibiting humoral responses and altering Th1/Th2 balance, increasing mortality in H9N2 infected birds.

Protocatechuic acid, a novel active substance against avian influenza virus H9N2 infection

Influenza virus H9N2 subtype has triggered co-infection with other infectious agents, resulting in huge economical losses in the poultry industry. Our current study aims to evaluate the antiviral activity of protocatechuic acid (PCA) against a virulent H9N2 strain in a mouse model. 120 BALB/c mice were divided into one control group, one untreated group, one 50 mg/kg amantadine hydrochloride-treated group and three PCA groups treated 12 hours post-inoculation with 40, 20 or 10 mg/kg PCA for 7 days. All the infected animals were inoculated intranasally with 0.2 ml of a A/Chicken/Hebei/4/2008(H9N2) inoculum. A significant body weight loss was found in the 20 mg/kg and 40 mg/kg PCA-treated and amantadine groups as compared to the control group. The 14 day survivals were 94.4%, 100% and 95% in the PCA-treated groups and 94.4% in the amantadine hydrochloride group, compared to less than 60% in the untreated group. Virus loads were less in the PCA-treated groups compared to the amantadine-treated or the untreated groups. Neutrophil cells in BALF were significantly decreased while IFN-γ, IL-2, TNF-α and IL-6 decreased significantly at days 7 in the PCA-treated groups compared to the untreated group. Furthermore, a significantly decreased CD4+/CD8+ ratio and an increased proportion of CD19 cells were observed in the PCA-treated groups and amantadine-treated group compared to the untreated group. Mice administered with PCA exhibited a higher survival rate and greater viral clearance associated with an inhibition of inflammatory cytokines and activation of CD8+ T cell subsets. PCA is a promising novel agent against bird flu infection in the poultry industry.