Detailed Instructions: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Problem:Knowledge of ancient viruses is limited due to their low concentration and poor preservation in ancient specimens. Using a viral particle-associated nucleic acid enrichment approach, we genetically characterized one complete DNA and one partial RNA viral genome from a 700-y-old fecal sample preserved in ice. Using reverse genetics, we reconstituted the DNA virus, which replicated and systemically spread in a model plant species. Under constant freezing conditions, encapsidated viral nucleic acids may therefore be preserved for centuries. Our finding indicates that cryogenically preserved materials can be repositories of ancient viral nucleic acids, which in turn allow molecular genetics to regenerate viruses to study their biology. 
  
 Abstract 
  
 Viruses preserved in ancient materials provide snapshots of past viral diversity and a means to trace viral evolution through time. Here, we use a metagenomics approach to identify filterable and nuclease-resistant nucleic acids preserved in 700-y-old caribou feces frozen in a permanent ice patch. We were able to recover and characterize two viruses in replicated experiments performed in two different laboratories: a small circular DNA viral genome (ancient caribou feces associated virus, or aCFV) and a partial RNA viral genome (Ancient Northwest Territories cripavirus, or aNCV). Phylogenetic analysis identifies aCFV as distantly related to the plant-infecting geminiviruses and the fungi-infecting Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 and aNCV as within the insect-infecting Cripavirus genus. We hypothesize that these viruses originate from plant material ingested by caribou or from flying insects and that their preservation can be attributed to protection within viral capsids maintained at cold temperatures. To investigate the tropism of aCFV, we used the geminiviral reverse genetic system and introduced a multimeric clone into the laboratory model plant Nicotiana benthamiana. Evidence for infectivity came from the detection of viral DNA in newly emerged leaves and the precise excision of the viral genome from the multimeric clones in inoculated leaves. Our findings indicate that viral genomes may in some circumstances be protected from degradation for centuries. ||||| Treatments 
  
 Ancient Viruses Lurk In Frozen Caribou Poo 
  
 i itoggle caption Courtesy of Brian Moorman Courtesy of Brian Moorman 
  
 A careful examination of frozen caribou poop has turned up two never-before-seen viruses. 
  
 The viruses are hundreds of years old: One of them probably infected plants the caribous ate. The other may have infected insects that buzzed around the animals. 
  
 The findings prove viruses can survive for surprisingly long periods of time in a cold environment, according to Eric Delwart, a researcher at Blood Systems Research Institute in San Francisco. 
  
 "The DNA of viruses is preserved extremely well under cold conditions," he says. 
  
 Delwart's day job at Blood Systems is to find new viruses that could contaminate the blood supply. But he enjoys looking in odd places too. He got interested in ice cores from high mountain regions, after reading about all the interesting old things the ice contained. 
  
 "Things like old shoes and arrowheads," he says, "and then I realized this is nature's freezer, which should also contain organic remains." 
  
 Delwart had one particular type of organic remains in mind: caribou poop. Just about everything an animal eats can be infected with a virus. And that makes animals, including humans, virus vacuums that suck up every virus in their path. 
  
 "I mean we're constantly shoving viruses down our throat and if you look at poo samples from humans and from animals you will find a lot of viruses," he says. 
  
 Caribous hang out on ice, so these pristine ice cores are actually full of poo. And as scientists go through layer after layer of ice, the poo gets older and older. 
  
 Delwart examined poop from northern Canada that was 700 years old. The result, published Monday in the Proceedings of the National Academy of Sciences, is the discovery of these two viruses. 
  
 The DNA was so well-preserved that Delwart's collaborators could even reconstitute one virus and use it to infect a plant in the lab. 
  
 As far as Delwart can tell, these viruses aren't dangerous, which is good. As the North warms and ice melts, more caribou poo infected with ancient viruses will be finding its way into the modern ecosystem. |||||
Solution:
If trekking into the wilds of northern Canada, drilling samples out of the ice core, and analyzing caribou poop to find a pair of really old viruses sounds like your idea of a hot Friday night, well, we present you Eric Delwart. As NPR reports, the viral researcher did just that with 700-year-old caribou scat after it occurred to him that the ice "is nature's freezer, which should also contain organic remains." And given that animals of all kinds are "constantly shoving viruses down our throat ... if you look at poo samples from humans and from animals you will find a lot of viruses," he reasoned. Delwart's theory panned out, and he found two previously undiscovered viruses. His results, published yesterday in the Proceedings of the National Academy of Sciences, found that DNA in one of the viruses was in such great shape that it could be used to infect a plant. And while Delwart doesn't think either is dangerous, NPR offers up this cautionary coda: "As the North warms and ice melts, more caribou poo infected with ancient viruses will be finding its way into the modern ecosystem." (Speaking of things perhaps best left alone, a lab has revived history's deadliest flu virus.)