Viunavirus

Members of the Viunavirus genus share a number of features that are distinguishable from other members of the Myoviridae family. The heads of these phages are icosahedral in nature. Furthermore, their tails are composed of a collared neck (similar in structure to that of a T4 phage), “a sheath surrounding a tail tube or core, a thin base plate, and an adsorption structure” Notably, a series of unique protrusions can be found stemming from the base plate of these organisms.[2] 3 to 4 thick, rounded prongs (located at the bottom of the base plate) and an equal number of thinner, star-like protrusions (attached to the sides of the baseplate via a stalk) have been observed in members of the genus. No other phages that were observed showed similar symmetrical structures.

Members of the genus are also similar in terms of genomics. All species in the genus showed above a 75% commonality in protein composition. While “the gene order is strongly conserved in all seven phages…various functional regions are randomly distributed throughout the genome…”.[2] Functional clustering, as observed in other genera of phages, is uniquely absent from Viunavirus, and proves to be a defining quality of the genus.

Due to the diversity in tail-spike filaments, researchers have suggested that these phages may be capable of infecting a wider range of hosts. One such example has already been observed: the species SFP10 has successfully infected of the Genus Salmonella and of the species E. coli. While all members of the genus possess tail spikes, it is important to note that each species may possess unique spikes, many of which must be further researched to determine their function.

In 2013, a study conducted by the University of Pittsburgh dealt with the analysis of the Salmonella phage Det7, a potentially new member of the Viunavirus genus (similar to Salmonella P22, of the family Podoviridae). Det7 shares 60 to 90 percent of its nucleotide synthesis with other members of the genus. Testing revealed that the Det7 strain was capable of infecting all hosts affected by Salmonella P22 and 9NA, along with a number of unique host targets.[3]