Browsing by Subject "sisäkalvollinen virus"

In recent years, icosahedral internal membrane-containing single-stranded DNA (ssDNA) phages have been identified. Phages phi18:4 and phi48:2, both infecting Cellulophaga baltica bacteria and isolated from the Baltic Sea, are part of this phage group. Circular ssDNA genomes of these phages are different in length, but they are packed into capsids of uniform size which is unusual among viruses. Initially, the phages were cultivated using their original C. baltica host strains #18 and #48 but during the study, spontaneously induced #18ind virus was observed to originate from the #18 strain and possessed a double-stranded DNA genome. These observations led to an examination of the phage’s host range, ultimately resulting in the use of the #48 strain as a host for both phages. The life cycle strategy of both phages was lytic and efficiently produced viral progeny in the #48 strain. Zymogram analysis was utilized to investigate the presence of peptidoglycan-degrading enzymes in the phage structure, assisting in host cell penetration. Two possible peptidoglycan hydrolyzing enzymes were observed for each phage, although sequence data suggested only one enzyme. The formation of virions was analyzed by exposing the viruses to biochemical conditions. Freezing and thawing, along with guanidine hydrochloride treatment, turned out to separate the lipid membranes and capsid proteins of the virions but require further optimization for a detailed examination of the protein composition of the membrane. This study together with other research findings, clarifies the structure, life cycle, and evolutionary relationship of lipid-containing ssDNA phages in the context of other phages. In the future, phi18:4 and phi48:2 could serve as model systems for further investigations into other discovered Cellulophaga ssDNA phages.