Streptomyces coeruleorubidus as a potential biocontrol agent for Newcastle disease virus

Abstract

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.

Revision of the full stereochemistry of telomycin

“…34 Telomycin has also been reported to be produced by Micromonospora schwarzwaldensis sp. Nov. 35 and Streptomyces coeruleorubidus 22 after isolation of the compound, high-resolution MS and NMR analyses and comparison with the original NMR data reported for the antibiotic. 28 In the two recent works by the groups of Müller and Magarvey, the correct connectivity of telomycin and its minor congeners in S. canus ATCC 12646 and S. canus ATCC 12647 has been unambiguously corroborated by high-resolution MS, MS/MS sequencing (over the linearized peptide obtained by mild basic hydrolysis) and 2D NMR spectroscopy further supported by the bioinformatic analysis of its nonribosomal peptide synthetase (NRPS) genes.…”

“…21 Furthermore, telomycin has been recently found to inhibit the hemagglutination activity of Newcastle disease virus, thus being claimed as a potential antiviral agent. 22 All these precedents place the antibiotic class of telomycins as a promising candidate to be rescued for further pharmaceutical development.…”

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

“…The bioactive metabolites of actinobacteria have antifungal, antibacterial, antiparasitic, antiviral, insecticidal, anticancer, antioxidant, and anti-inflammatory activities. These metabolites have a considerable impact on the control of many infectious diseases as well as the pharmaceutical industry’s development ( Barka et al., 2016 ; Rajaram et al., 2020 ; Abdelaziz et al., 2022 ). A pentacyclic triterpenoid known as ursolic acid has been linked to a variety of biological activities ( Gu et al., 2015 ).…”