New microbial origin compound capable of destruct T4 bacterial phage structure

Abstract

Background: We have isolated culture of Streptomyces species that was able to degrade orchid virus capsid proteins and inhibiting virus infection. Odontoglossum ringspot virus infection could be greatly reduced by incubation with the bacterial culture. The infectivity to T4 was reduced after incubation of these culture filtrates, suggesting the activity of the culture filtrate could extend to non-plant viruses. Objectives: To further verify whether the reduction of the infectivity to T4 phage could result in visually measurable difference in the virus morphology after treatment of the bacterial culture. Methods: The T4 phage was grown in DH5-α strain of E coli, and collected in the culture medium. The phage containing medium was filtered with 0.45 μM filter. Two strains of Streptomyces spp, SML-1 and C5-6, were selected based on their optimal growth. The effects of culture filtrate of these two strains on destroying the T4 phage was tested. Morphology of T4 bacteriophage was inspected by atomic force microscopy (AFM). The culture filtrates of SML-1 and CA5-06 strains were diluted to 1/4, and mixed 1:1 to the T4 phage suspension, incubated for 30 minutes, before further 10x and 100x dilution. The mixture was dried on mica and observed using AFM. Results: The culture filtrate of CA5-06 strain is capable of reducing the fragment of the head of T4 phage from an average of 66.5nm to 53.3nm (1/8 dilution). The culture filtrate of SML-1 strain is capable of reducing the fragment of the head of T4 phage from an average of 66.5nm to 62.3nm (1/8 dilution). The data obtained helped to develop practical application methods of the culture filtrates to control virus spreading.