Can standard viruses infect bacteria? I'm not speaking of bacteriophage but typical RNA and DNA virus such as influenza and Ebola.

  • $\begingroup$ That's a very human-centric view. There are more bacteriophages floating around this planet than anything else. Phages are your "typical" viruses, Influenza and Ebola are the weird ones. $\endgroup$ – Amory Aug 27 '14 at 3:09
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    $\begingroup$ I like this question is fine and should stay open. Lots of good things are correcting misconceptions. $\endgroup$ – user1357 Aug 27 '14 at 6:58
  • $\begingroup$ All viruses that infect bacteria are known as bacteriophages. In your question you mention the "typical RNA and DNA viruses", however, bacteriophages also contain DNA, which is often double-stranded DNA. $\endgroup$ – miwadora Aug 28 '14 at 2:49
  • $\begingroup$ Some viruses even infect other viruses! There are still very few examples and in addition to that those examples involve host species that are on the boundary of the definition of what is a virus. You may want to have a look to mamavirus and its parasite: sputnik. Also one may want to have a look to Marseillevirus (named after the University of Marseille), Lausannevirus (named after the University of Lausanne) and mimivirus. $\endgroup$ – Remi.b Aug 28 '14 at 6:18

I'm not so sure about my answer. But I think "bacteriophage" is a polyphyletic name of which was defined by the ability of infecting bacteria, but not defined by the genetic, evolutionary, or morphological relationships.

It seems that if a species (or a taxon in a higher taxonomic level) of virus is infectious to bacteria, it will be classified as a member of the bacteriophage.

Here is a review article about the phage classification.

  • $\begingroup$ this is a fine answer to a fine question $\endgroup$ – user1357 Aug 27 '14 at 6:57
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    $\begingroup$ Tailed phages (Caudovirales) are an ancient monophyletic viral taxon, and include species that infect bacteria and species that infect archaea. People often use the term bacteriophage as a synonym to them. Caudovirales are the most abundant biological entities on the planet. There are three families: Myoviridae, Podoviridae and Siphoviridae, which are characterized by linear dsDNA genomes and unique head-tail morphology. Eukaryote-infecting Herpesviridae are believed to be related to Caudovirales. $\endgroup$ – 5heikki Aug 27 '14 at 9:05

The word infect is an encapsulation of several activities: transcription, translation, viral entry, budding, lysis, etc. When you ask if a eukaryotic virus (influenza, ebola) can infect a prokarytoic cell (bacteria) you are asking if these viruses can do the same activities. The answer is no.

  • Translation is mediated by ribosomes, which are different in prokaryotes/eukaryotes.
  • Transcription is mediated by viral RNA polymerase which may be contained in viral nucleic acid. This is possible, but useless without translation of the mRNA.
  • Viral entry is mediated by cell surface features and would be incompatible for eukaryotic viral entry into prokaytoic cells, and the reverse.
  • Viral budding is mediated by viral proteins inserted into the cell membrane. This is prohibited since a eukaryotic virus is unable to enter a prokaryotic cell/translate its proteins.
  • Lysis is mediated by excessive buildup of viral particles inside a cell. This is also prohibited by an incompatibility of eukaryotic/prokaryotic cell surface, translation machinery.

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