Jan 2018: Scientists discover new type of viruses never seen before, "Autolykiviridae," in oceans

According to the researchers, the most abundant viruses on the entire planet are double-stranded DNA (dsDNA) viruses, of which the ‘tailed’ variety (Caudovirales) are the most well-known to science.
Their mysterious tail-less counterparts are far less understood, chiefly because their biological characteristics aren’t easily picked up by common tests.
But that doesn’t mean they can’t be found. In their new study, the researchers were able to incubate tail-less viruses extracted from the waves lapping Massachusetts’ shores, and sequenced their DNA.
The team calls their discovery Autolykiviridae, after Autolykos (“the wolf itself”): a character from Greek mythology, who as a trickster and thief proved similarly tricky to catch.
But Autolykiviridae has been caught, and now that we know about it, the discovery is helping scientists to fill in a large missing link in virus evolution.
The tail-less viruses look to be representatives of an ancient viral lineage defined by specific types of capsids, the protein shell that encases viral DNA — which we knew commonly infects animals and single-celled organisms, but not bacteria.
futurism.com/new-ocean-viruses-weird-dna/
Here we characterize a group of marine dsDNA non-tailed viruses with short 10-kb genomes isolated during a study that quantified the diversity of viruses infecting Vibrionaceae bacteria.
These viruses, which we propose to name the Autolykiviridae, represent a novel family within the ancient lineage of double jelly roll (DJR) capsid viruses. Ecologically, members of the Autolykiviridae have a broad host range, killing on average 34 hosts in four Vibrio species, in contrast to tailed viruses which kill on average only two hosts in one species.
www.nature.com/articles/nature25474
January 24, 2018
A type of virus that dominates water samples taken from the world’s oceans has long escaped analysis because it has characteristics that standard tests can’t detect. However, researchers at MIT and the Albert Einstein College of Medicine have now managed to isolate and study representatives of these elusive viruses, which provide a key missing link in virus evolution and play an important role in regulating bacterial populations, as a new study reports.
Viruses are the main predators of bacteria, and the findings suggest that the current The results are being reported this week in the journal Nature.
The newly identified viruses lack the “tail” found on most catalogued and sequenced bacterial viruses, and have several other unusual properties that have led to their being missed by previous studies.
To honor that fact, the researchers named this new group the Autolykiviridae — after a character from Greek mythology who was storied for being difficult to catch. And, unlike typical viruses that prey on just one or two types of bacteria, these tailless varieties can infect dozens of different types, often of different species, underscoring their ecological relevance.
news.mit.edu/2018/new-type-virus-found-ocean-0124
“One aspect of our study that helped us detect them was the longer time we waited when we first tried to grow them from seawater samples,” she explained. “Since many of them grew more slowly than the tailed viruses, this let us catch them where other studies might have missed them.”
The researchers found that Autolykiviridae were also much less choosy about their prey than their bacteria-hunting cousins. While most viruses seek out only one or two species of bacteria, the new group preyed on dozens of different bacteria types and infected many different species, the study authors reported.
And this ocean virus group is very likely thriving elsewhere, too — in fact, a closely related group may even reside within our own digestive systems, study co-author Libusha Kelly, an assistant professor of systems and computational biology, and of microbiology and immunology at the Albert Einstein College of Medicine, said in a statement.
“We’ve found related viral sequences in the gut microbiome,” Kelly said. “But we don’t yet know how they influence microbial communities in the gut or how important they are for health.”
The findings were published online yesterday (Jan. 24) in the journal Nature.
www.livescience.com/61527-new-ocean-virus-identified.html
 
h/t Digital mix guy