Alpha-sitosterol: a new antiviral agent produced by Streptomyces misakiensis and its potential activity against Newcastle disease virus.

BACKGROUND: Newcastle Disease Virus (NDV) causes severe economic losses in the poultry industry worldwide. Hence, this study aimed to discover a novel bioactive antiviral agent for controlling NDV. Streptomyces misakiensis was isolated from Egyptian soil and its secondary metabolites were identified using infrared spectroscopy (IR), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) spectroscopy. The inhibitory activity of bioactive metabolite against NDV were examined. Three experimental groups of 10-day-old specific pathogen-free embryonated chicken eggs (SPF-ECEs), including the bioactive metabolite control group, NDV control positive group, and α-sitosterol and NDV mixture-treated group were inoculated. RESULTS: α-sitosterol (Ethyl-6-methylheptan-2-yl]-10,13-dimethyl-dodecahydro-1H-cyclopenta[a]phenanthren-3-ol), a secondary metabolite of S. misakiensis, completely inhibited hemagglutination (HA) activity of the NDV strain. The HA activity of the NDV strain was 8 log2 and 9 log2 for 0.5 and 0.75% RBCs, respectively. The NDV HA activity for the two concentrations of RBCs was significantly (P < 0.0001) inhibited after α-sitosterol treatment. There was a significant (P < 0.0001) decrease in the log 2 of HA activity, with values of - 0.500 (75%, chicken RBCs) before inoculation in SPF-ECEs and - 1.161 (50%, RBCs) and - 1.403 (75%, RBCs) following SPF-ECE inoculation. Compared to ECEs inoculated with NDV alone, the α-sitosterol-treated group showed improvement in histological lesion ratings for chorioallantoic membranes (CAM) and hepatic tissues. The CAM of the α-sitosterol- inoculated SPF-ECEs was preserved. The epithelial and stromal layers were noticeably thicker with extensive hemorrhages, clogged vasculatures, and certain inflammatory cells in the stroma layer in the NDV group. However, mild edema and inflammatory cell infiltration were observed in the CAM of the treated group. ECEs inoculated with α-sitosterol alone showed normal histology of the hepatic acini, central veins, and portal triads. Severe degenerative alterations, including steatosis, clogged sinusoids, and central veins, were observed in ECEs inoculated with NDV. Mild hepatic degenerative alterations, with perivascular round cell infiltration, were observed in the treated group. CONCLUSION: To the best of our knowledge, this is the first study to highlight that the potentially bioactive secondary metabolite, α-sitosterol, belonging to the terpene family, has the potential to be a biological weapon against virulent NDV. It could be used for the development of innovative antiviral drugs to control NDV after further clinical investigation.

Bioactive metabolites of Streptomyces misakiensis display broad-spectrum antimicrobial activity against multidrug-resistant bacteria and fungi.

Background: Antimicrobial resistance is a serious threat to public health globally. It is a slower-moving pandemic than COVID-19, so we are fast running out of treatment options. Purpose: Thus, this study was designed to search for an alternative biomaterial with broad-spectrum activity for the treatment of multidrug-resistant (MDR) bacterial and fungal pathogen-related infections. Methods: We isolated Streptomyces species from soil samples and identified the most active strains with antimicrobial activity. The culture filtrates of active species were purified, and the bioactive metabolite extracts were identified by thin-layer chromatography (TLC), preparative high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry (GC-MS). The minimum inhibitory concentrations (MICs) of the bioactive metabolites against MDR bacteria and fungi were determined using the broth microdilution method. Results: Preliminary screening revealed that Streptomyces misakiensis and S. coeruleorubidus exhibited antimicrobial potential. The MIC50 and MIC90 of S. misakiensis antibacterial bioactive metabolite (ursolic acid methyl ester) and antifungal metabolite (tetradecamethylcycloheptasiloxane) against all tested bacteria and fungi were 0.5 µg/ml and 1 µg/mL, respectively, versus S. coeruleorubidus metabolites: thiocarbamic acid, N,N-dimethyl, S-1,3-diphenyl-2-butenyl ester against bacteria (MIC50: 2 µg/ml and MIC90: 4 µg/mL) and fungi (MIC50: 4 µg/ml and MIC90: 8 µg/mL). Ursolic acid methyl ester was active against ciprofloxacin-resistant strains of Streptococcus pyogenes, S. agalactiae, Escherichia coli, Klebsiella pneumoniae, and Salmonella enterica serovars, colistin-resistant Aeromonas hydrophila and K. pneumoniae, and vancomycin-resistant Staphylococcus aureus. Tetradecamethylcycloheptasiloxane was active against azole- and amphotericin B-resistant Candida albicans, Cryptococcus neoformans, C. gattii, Aspergillus flavus, A. niger, and A. fumigatus. Ursolic acid methyl ester was applied in vivo for treating S. aureus septicemia and K. pneumoniae pneumonia models in mice. In the septicemia model, the ursolic acid methyl ester-treated group had a significant 4.00 and 3.98 log CFU/g decrease (P < 0.05) in liver and spleen tissue compared to the infected, untreated control group. Lung tissue in the pneumonia model showed a 2.20 log CFU/g significant decrease in the ursolic acid methyl ester-treated group in comparison to the control group. The haematological and biochemical markers in the ursolic acid methyl ester-treated group did not change in a statistically significant way. Moreover, no abnormalities were found in the histopathology of the liver, kidneys, lungs, and spleen of ursolic acid methyl ester-treated mice in comparison with the control group. Conclusion: S. misakiensis metabolite extracts are broad-spectrum antimicrobial biomaterials that can be further investigated for the potential against MDR pathogen infections. Hence, it opens up new horizons for exploring alternative drugs for current and reemerging diseases.

Insights into Genetic Characteristics and Virological Features of Endemic Avian Influenza A (H9N2) Viruses in Egypt from 2017-2021.

From 2010 to 2013, genotype I avian influenza A(H9N2) viruses of the G1-lineage were isolated from several poultry species in Egypt. In 2014, novel reassortant H9N2 viruses were detected in pigeons designated as genotype II. To monitor the subsequent genetic evolution of Egyptian A(H9N2) viruses, we characterized the full genomes of 173 viruses isolated through active surveillance from 2017 to 2022. In addition, we compared the virological characteristics and pathogenicity of representative viruses. Phylogenetic analysis of the HA indicated that all studied sequences from 2017-2021 were grouped into G1-like H9N2 viruses previously detected in Egypt. Phylogenetic analysis indicated that the Egyptian A(H9N2) viruses had undergone further reassortment, inheriting four genes (PB2, PB1, PA, NS) from genotype II, with their remaining segments deriving from genotype I viruses (these viruses designated as genotype III). Studying the virological features of the two most dominant genotypes (I and III) of Egyptian H9N2 viruses in vitro and in vivo indicated that both replicated well in mammalian cells, but did not show any clinical signs in chickens, ducks, and mice. Monitoring avian influenza viruses through surveillance programs and understanding the genetic and antigenic characteristics of circulating H9N2 viruses are essential for risk assessment and influenza pandemic preparedness.

Streptomyces coeruleorubidus as a potential biocontrol agent for Newcastle disease virus.

BACKGROUND: Newcastle disease virus (NDV) is a severe disease that affects domestic and wild birds. Controlled antibiotics derived from probiotics have been examined as prospective solutions for preserving seroconversion in NDV-vaccinated fowl. In this study, the secondary metabolite "telomycin" was extracted from Streptomyces coeruleorubidus (S. coeruleorubidus) isolated from Egypt's cultivated soil. The structure of telomycin was determined by the elucidation of spectroscopic analysis, including nuclear magnetic resonance (NMR) and mass spectrometry (MS) spectra, and comparison with the literature. The antiviral activity of the secondary metabolite was tested by checking its effect on NDV hemagglutination activity (HA). Moreover, HA of NDV was tested after inoculation of NDV (control) and a combination of telomycin and NDV in 10- days- specific pathogen-free embryonated chicken eggs (SPF-ECE) daily candling. Histopathological examination was performed for chorioallantoic membranes and liver of SPF-ECE. RESULTS: S. coeruleorubidus secondary metabolite "telomycin" showed complete hemagglutination inhibition (HI) activity of NDV strain (MN635617) with log106 infectivity titers (EID50/mL). The HA of NDV strain was 8 log2 and 9 log2 with 0.5% and 0.75% of chicken RBCs, respectively. Preserved structures of chorioallantoic-membranes (CAM) with dilated capillary networks were observed in the treated group inoculated with telomycin and NDV. Histological changes in SPF-ECE liver were examined after inoculation in ova to further characterize the telomycin effect. Telomycin and NDV mixture inoculated group showed preserved cytoarchitecture of hepatocytes with the presence of perivascular foci of lymphocytes. The group that was inoculated with telomycin alone showed normal histology of hepatic acini, central veins, and portal triads. CONCLUSION: S. coeruleorubidus telomycin is a promising bioactive agent that might be a biological weapon against a deadly chicken NDV that costs farmers a lot of money.

Incidence and seroprevalence of seasonal influenza a viruses in Egypt: Results of a community-based cohort study.

BACKGROUND: H1N1 and H3N2 influenza A viruses circulate in people as seasonal influenza viruses. Data on influenza infection rates and circulation in demographic subpopulations in Egypt are limited. In this study, we aimed to determine the incidence and seroprevalence of seasonal influenza A virus infections in a cohort of rural Egyptians between 2017 and 2020. METHODS: A total of 2383 subjects were enrolled from 390 households in five study sites in Northern Egypt. Informed consents were obtained. Sera were collected from participants on an annual basis (Baseline: 2016-2017, Follow up 1: 2017-2018, Follow up 2: 2018-2019, and Follow up 3: 2019-2020) to determine seroprevalence of antibodies against H1N1 and H3N2 viruses by hemagglutination inhibition assay and to estimate incidence based on seroconversion. RESULTS: Seropositivity against H1N1 was over 40% and over 60% against H3N2. The high seroprevalence was due to natural infection because participants were mostly unvaccinated. Seropositive participants were younger than seronegative participants indicating that the infection rate is higher in children. Incidence of both viruses ranged from 4% to 28% depending on study year. The incidence and seroprevalence of H3N2 and H1N1 infections at Follow up 1, 2, and 3 showed an increase at Follow up 2 observed for all age categories corresponding to season 2018-2019, at which the vaccine efficacy was the lowest worldwide compared with preceding and following seasons. CONCLUSIONS: This cohort study provided estimates of influenza A infection rates among rural Egyptians. We recommend updating influenza vaccination programs to focus on such populations.

Cross-reaction between mouse and rat immunoglobulin G: does it matter in sandwich ELISA?

BACKGROUND: Sandwich ELISA is an ideal antigen detection and quantification assay. Recently, it was used as the basic concept for high technology diagnostics. The specificity of the assay depends on the exclusion of detection cross-reactivity which arises from using two antibodies developed in different species. Since mice and rats are the common laboratory animals used to develop antigen specific antibodies. Therefore, the questions we addressed here were (1) can one use antigen-specific antibodies raised in mice and rats in the same assay to specifically detect/quantify antigens? and (2) which antibodies of the two rodents should be placed for capturing and for detection in the antigen-detection sandwich? RESULTS: Direct ELISA assay was used to assess for the specific reaction of the HRP-conjugated antibody to the target serum. First reaction was to compare between either conjugate anti-rat IgG (homologous) or anti-mouse IgG (heterologous) for the detection of rat sera IgG. Following the dilution factor optimization, the O.D. were 0.744±0.051 and 0.604±0.05, respectively (p= .004). The difference in mean O.D. of 0.14 reflected an unaccepted non-specific reaction. The second reaction was to compare between either conjugate anti-mouse IgG (homologous) and anti-rat IgG (heterologous) for the detection of mouse sera IgG. The recorded O.D. were 0.9414±0.14 and 0.317 ±0.141, respectively (p= .0002). The improved difference in mean O.D. of 0.624 reflecting a minimized cross-reaction. CONCLUSIONS: Our results suggest that it is possible to use both Swiss albino mice and albino rats in a single sandwich ELISA, given that the captured antibody species to be from the Swiss albino mice and the detection antibody to be from the albino rat. The described working details are limited to the source of the antibodies used in the study. However, the approach stresses on the importance of such optimization steps before making any interpretations based on the antigen detection. To our knowledge, this study is the first to cover the optimal order of the capturing and the detection antibodies in a sandwich ELISA assay. In addition to addressing the possible interfering cross-reactivity that result from using mouse and rat serum antibodies in a single assay.

Presence of HPV, EBV and HMTV Viruses Among Egyptian Breast Cancer Women: Molecular Detection and Clinical Relevance.

BACKGROUND: Oncogenic viruses, their possible association with breast cancer (BC) and effect on its clinical course are interesting issue. The present study evaluates the presence of human papillomavirus (HPV), EpsteinBarr virus (EBV), and human mammary tumor virus (HMTV) in BC and their relation with clinico-pathological characteristics. PATIENTS AND METHODS: This study was conducted on 80 Egyptian women with BC and 30 control women without known oncological disease. Forty formalin-fixed paraffin-embedded (FFPE) tissues, forty fresh tissue samples, and white blood cells (WBCs) of BC patients and WBCs of controls were subjected to a qualitative polymerase chain reaction (PCR). Quantitative real-time PCR was used to measure viral loads in fresh tissues of BC. The result was correlated with clinico-pathological characteristics of BC. RESULTS: HPV was detected in 33 (41.25%), EBV in 30 (37.5%) and HMTV in 33 (41.25%) BC patients. None of the control women was positive for HPV or EBV while HMTV was detected in 7 (23.3%). Among 40 BC WBCs specimens, HPV/HMTV were found together in 25%, followed by EBV/HMTV in 2.5% and EBV/HPV in 2.5%. However, the three viruses (HPV/EBV/HMTV) were found together in only 5%. In the 40 fresh BC tissues, the three viruses were found together in 12 (30%), EBV/HMTV in 7 (17.5%), HPV/HMTV in 4 (10%), and HPV/EBV in 4 (10%). EBV, HMTV, or multiple viral infections were associated with younger age of BC women. HPV, EBV, and HMTV median loads in fresh tissues were 4.8×103 copies/µL, 6.3×103 copies/µL, and 97 copies/µL, respectively. CONCLUSION: WBCs could be a more suitable specimen instead of fresh tissue for HMTV detection in BC patients to avoid invasive procedures. The presence of HPV, EBV, and HMTV together in Egyptian women with BC was significantly associated with younger age.

Establishment of serum derived infectivity coculture model for enhancement of hepatitis C virus replication in vitro.

BACKGROUND AND AIMS: Although HCV is one of the major health problems worldwide with the highest prevalence of genotype 4a in Egypt, it is poorly understood because of the limitations of having a robust in vitro model that allows the investigation and understanding of viral pathogenesis and life cycle. Genomic replicons for HCV are widely used and proved to have strong replication efficiency in cell culture, however, they are not able to produce infectious particles to enable the investigation of the whole viral life cycle and they mostly represent few sub-genomic classes for HCV. Hence, Genotype specific replication system is necessary to address specific sub-genomic phenotypes related to Hepatitis C pathogenicity. METHODS: In this study we attempt to develop a sustainable co-culture model, which potentially provides essential route of infection for HCV by using HCV-positive sera from infected patients. In this novel in vitro model, we tested the viral replication in co-cultured Huh 7.5 and HepG2 cells in order to sustain full viral replication cycle. We used high viral load serum of HCV-infected patients (10 × 106 to 20 × 106 IU/ml) as a source for HCV particles to infect co-cultured cells for 7 days. RESULTS AND CONCLUSIONS: Viral replication capacity was increased 3-5 folds in the coculture condition compared to the individual cell lines, which indicates an improvement to viral infectivity in vitro. SIGNIFICANCE STATEMENT: This novel coculture system represents a new in vitro model that will help study the underlying mechanisms of HCV pathogenicity.

Cyclooxygenase-2 expression is associated with elevated aspartate aminotransferase level in hepatocellular carcinoma.

BACKGROUND: Cyclooxygenase-2 (COX-2), the inducible rate-limiting enzyme of prostaglandins biosynthesis, is involved in the pathogenesis of many chronic inflammation-related human malignancies including hepatocellular carcinoma (HCC). However, its clinical significance in HCC remains obscure. The aim of our study was to evaluate COX-2 expression in HCC and correlate its expression to both clinicopathological parameters and patients survival. MATERIALS AND METHODS: The present study was conducted on 17 HCC and 21 adjacent nontumor liver tissues obtained from 22 HCC patients underwent hepatectomy. Eight normal liver tissues taken from normal donors and HepG2 cells were used as controls. Total RNA was extracted and COX-2 mRNA was detected by reverse transcription polymerase chain reaction and correlated to the clinicopathological criteria and to patient's survival. RESULTS: COX-2 mRNA was detected in 58.8% of the HCC tissues and in 28.6% of the adjacent nontumor liver tissues. COX-2 expression was significantly associated with elevated levels of serum aspartate aminotransferase (AST) with high specificity for disease detection. There was no significance between COX-2 expression and any of the histopathological criteria. CONCLUSIONS: COX-2 expression may be involved in HCC carcinogenesis with high specificity for disease detection. COX-2 expression is significantly associated with elevated AST levels indicating a mechanism that may correlate both markers. However COX-2 expression seems to be an independent factor with no correlation to any of the histopathological data or patient's survival.

Molecular cloning and immunogenicity evaluation of rotavirus structural proteins as candidate vaccine.

The middle capsid protein of rotavirus, VP6, constitutes approximately 51% of the virion by weight. The high degree of identity (>87-99%) in the primary amino acid sequences of VP6 proteins from mammalian rotaviruses suggests VP6-based vaccines could potentially provide heterotypic protection. For this reason, significant effort has been directed toward producing recombinant rotavirus VP6 vaccines. We have cloned and expressed 155bp of the VP6 most frequent in Egyptian rotavirus sewage isolates, encoding the VP6 protein in the pET30b vector having an apparent molecular mass of 12.5kDa. The recombinant VP6 expressed by the transformants was detected by SDS-PAGE analysis. Rabbits immunized with the recombinant rotavirus expressed VP6 elicited VP6-specific IgG antibodies that provided significant reductions in the infectious units of the Egyptian rotavirus sewage isolate and human reference rotavirus Wa strain in vitro assay.

Antigenic diversity and cross-reactivity of avian influenza H5N1 viruses in Egypt between 2006 and 2011.

Influenza epidemics are a major health concern worldwide. Highly pathogenic avian influenza (HPAI) H5N1 viruses in Egypt have been subject to rapid genetic and antigenic changes since the first outbreak in February 2006 and have been endemic in poultry in Egypt since 2008. In this study, 33 H5N1 viruses isolated from avian hosts were antigenically analysed by using a panel of eight mAbs raised against the A/Viet Nam/1203/04 (H5N1; clade 1) and A/bar-headed goose/Qinghai-lake/1A/05 (H5N1; clade 2.2) influenza viruses. Rats were immunized with inactivated whole-virus vaccine produced by reverse genetics with the haemagglutinin and neuraminidase genes of eight antigenically different HPAI H5N1 virus isolates and six internal genes from A/Puerto Rico/8/1934 (PR8) to produce polyclonal antibodies. Cross-reactivity between the obtained polyclonal antibodies and the isolated viruses was assayed. Antigenic cartography of the isolated viruses showed that three antigenic clusters were defined based on haemagglutination inhibition (HI) analysis using mAbs and the majority of viruses isolated in 2010 and 2011 fell into two of these clusters. An antigenic map based on polyclonal rat antisera showed that all virus isolates fell within one extended cluster. Accordingly, continuous surveillance and antigenic characterization will help us determine which virus isolate(s) should be used in poultry vaccine preparation.

Comparative Assessment of Mammalian Reoviruses versus Enteroviruses as Indicator for Viral Water Pollution.

UNLABELLED: Enteric viruses are important causative agents of human diseases. Among the enteric viruses, reoviruses and enteroviruses are prevalent in various aquatic environments. This study was carried out to detect and compare the presence of reoviruses and enteroviruses by ICC-PCR in one wastewater and three drinking water treatment plants, studying the possibility of using reoviruses as indicator of viral water pollution and genotyping of the isolated strains. One hundred and forty four drinking water and 76 wastewater samples were collected for two years. Reoviruses and enteroviruses were detected in 12.5% (18/144) and 8.3% (12/144) of total collected drinking water samples. In the studied wastewater treatment plant (WWTP), reoviruses were detected in 26% (20/76) of total collected samples while enteroviruses were detected in 21% (16/76) of the total collected samples. Phylogenic analysis revealed that our sequences were closely related to reovirus type 1, Lang strain and Human poliovirus type1. CONCLUSION: The higher incidence of reoviruses than enteroviruses reflects the possibility of using reoviruses as indicator of water pollution.

Cell mediated responses to the mycobacterium tuberculosis specific ESAT-6 antigen in Egyptian tuberculosis patients.

Human T cell responses and gamma interferon (IFN-gamma) secretion by peripheral blood mononuclear cells (PBMCs) in response to M. tuberculosis Early Secretory Antigen Target-6 (ESAT-6) eight synthetic overlapping peptides, were investigated in Egyptian tuberculosis patients as well as a control group. Three cell mediated immunoassays (lymphoproliferative, ELISPOT and intracellular flowcytometry) have been employed in this study to determine the ability of ESAT-6 to induce T-cell responses and IFN-gamma secretion, which play a critical role in protective cell-mediated immunity against tuberculosis (TB). The results revealed that all ESAT-6 peptides (P1-P8) were recognized by 85% of infected TB-patients, indicating that the molecule holds multiple epitopes. However, patients differed in the fine specificity of their peptide responses. Recognition of the N-terminal region of (P2-P7) was predominant. This study demonstrates that ESAT-6 is frequently recognized during infection and holds potential as a component of a future TB-vaccine.