hijacking of cell functions for replication

[Steven Avery]

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Garet Bĕlohlávek

The continental tradition exemplified by Foucault attacks Science as an apparatus of hegemony, but leaves intact the ontological inventory, that indefinitely extensible set of scientific entities...

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[Steven Avery]

what things other than viruses can hijack cell processes for replication

Beyond viruses, various biological entities and genetic elements can hijack host cell processes for their own replication. They use the cell's machinery to duplicate their genomes or synthesize proteins, operating either as independent pathogens or as parasitic sequences within the host's own DNA. [1, 2, 3]





Key Entities that Hijack Cells

• Plasmids & Transposons: Often called "jumping genes," transposons are specific sequences of DNA that can move or replicate themselves to different positions within the genome. Plasmids are small, circular DNA molecules (commonly found in bacteria) that hijack cellular enzymes to duplicate independently of the host's chromosomal DNA. [1, 2]
• Intracellular Bacteria: Certain bacteria, such as Chlamydia and Rickettsia, are obligate intracellular parasites. They have evolved to invade host cells, actively suppress the cell's immune responses, and redirect the cell's metabolism to provide the nutrients and energy needed for their own
  • replication. [1, 2, 3]
  • Viroids: These are the smallest known infectious pathogens, consisting solely of a short, circular, single-stranded RNA molecule. They do not encode proteins; instead, they hijack the host cell’s RNA polymerase to replicate their own genome, ultimately disrupting normal cellular function.
  • Prions: Unlike other hijackers that rely on nucleic acids (DNA/RNA), prions are misfolded proteins. They replicate by coercing properly folded proteins of the same type to adopt their abnormal, disease-causing shape. This process sets off a chain reaction that hijacks the host's normal protein-folding machinery. [1, 2, 3, 4, 5]
  • Cancer Cells: Malignant tumors can functionally "hijack" the physiological processes of the body. They alter host cell metabolism (such as heavily increasing glucose uptake in a process known as the Warburg effect) to fuel uncontrollable cell division and promote the growth of blood vessels to feed themselves. [1]
• 
  Understanding these non-viral hijackers offers valuable insight into cellular evolution, genetic diseases, and mechanisms of infection.
  
  
  If you are interested, I can:
  
  
  • Detail how intracellular bacteria avoid host immune detection.
  • Explain the mechanism of prion diseases like Creutzfeldt-Jakob.
  • Explore how transposons drive genetic diversity. [1, 2]
• 
  Let me know what you'd like to explore further.
  
  

 

[Steven Avery]

These are results for what was the one non-circular original seminal scientific experiment that showed that viruses actually hijacked the cell machinery functions for viral replication ? when did this change from a proposed theory to a scientific fact? thanks!
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AI Overview



The non-circular, seminal scientific experiment that definitively proved viruses hijack host cell machinery is the Hershey-Chase blender experiment (1952).
Wikipedia +1

By radiolabeling viral protein coats and viral DNA separately, Alfred Hershey and Martha Chase demonstrated that only viral DNA enters the host bacterium, yet it compels the cell to produce entirely new viral particles.
National Human Genome Research Institute (NHGRI) (.gov)

This shifted viral replication from a proposed theory to accepted scientific fact in the 1950s. It gained universal traction due to simultaneous leaps in molecular biology that defined the Central Dogma of Molecular Biology and deciphered the genetic code.
PubMed Central (PMC) (.gov) +2


The Hershey-Chase Experiment
Before 1952, many scientists hypothesized that viruses (then known as bacteriophages) were either independent organisms or that their structural proteins carried the instructions for replication. Hershey and Chase used the T2 bacteriophage, a virus made strictly of a DNA core wrapped in a protein coat:
Wikipedia +3

• They grew one batch of viruses with radioactive sulfur (which labels proteins but not DNA).
  National Human Genome Research Institute (NHGRI) (.gov)
  
  
• They grew another batch with radioactive phosphorus (which labels DNA but not proteins).
  National Human Genome Research Institute (NHGRI) (.gov)
  
  
• They allowed each batch to infect E. coli bacteria and knocked the empty viral coats off the outside of the cells using a standard kitchen blender.
  Wikipedia +1
  
  
• Upon centrifugation, they found that the radioactive phosphorus (DNA) entered the bacteria, while the radioactive sulfur (protein) remained outside.
  National Human Genome Research Institute (NHGRI) (.gov)
  

The Proof: Because only the viral genetic material entered the cell and subsequently directed the bacterial machinery to assemble hundreds of new, complete viruses, it was definitively proven that viruses are genetic parasites relying entirely on the host's translation and replication factories.
National Human Genome Research Institute (NHGRI) (.gov) +2


The Shift to Scientific Fact
The conclusion that viruses completely commandeered cellular processes transitioned from hypothesis to scientific fact through several overlapping milestones:

1. The 1939 One-Step Growth Curve: Studies by Max Delbrück and Emory Ellis established the "eclipse" period, proving that viruses don't multiply like living cells, but vanish inside the host only to reappear later after synthesis.
   
   
   Virology Blog +1
   
   
2. The 1953 DNA Structure Discovery: Watson and Crick’s elucidation of the double helix immediately gave biochemists a mechanical framework for how viral DNA could serve as a template inside the host cell nucleus.
   Embryo Project Encyclopedia
   
   
3. The 1960s Molecular Era: The discovery of messenger RNA (mRNA) and the deciphering of the genetic code proved that the host's ribosomes literally read the virus's rogue genetic instructions instead of the cell's normal commands.
   Khan Academy·NOVA PBS Official +1
   

Because of the elegance and clarity of these studies, Alfred Hershey was awarded the Nobel Prize in Physiology or Medicine in 1969.
Embryo Project Encyclopedia