(Image: © Shutterstock) Huge bacteria-killing viruses lurk in ecosystems around the world from hot springs to freshwater lakes and rivers. Now, a group of researchers has discovered some of these so-called bacteriophages that are so large and so complex that they blur the line between living and nonliving, according to new findings.
Bacteriophages, or "phages" for short, are viruses that specifically infect bacteria . Phages and other viruses are not considered living organisms because they can’t carry out biological processes without the help and cellular machinery of another organism.
That doesn’t mean they are innocuous: Phages are major drivers of ecosystem change because they prey on populations of bacteria, alter their metabolism, spread antibiotic resistance and carry compounds that cause disease in animals and humans, according to the researchers in a new study, published Feb. 12 in the journal Nature .
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To learn more about these sneaky invaders, the researchers searched through a DNA database that they created from samples they and their colleagues collected from nearly 30 different environments around the world, ranging from the guts of people and Alaskan moose to a South African bioreactor and a Tibetan hot spring, according to a statement.
From that DNA, they discovered 351 huge phages that had genomes four or more times larger than the average genome of phages. Among those was the largest phage found to date with a genome of 735,000 base pairs — the pairs of nucleotides that make up the rungs […]