Molecular Koch's postulates

Molecular Koch's postulates

Molecular Koch's postulates are a set of experimental criteria that must be satisfied to show that a gene found in a pathogenic microorganism encodes a product that contributes to the disease caused by the pathogen. Genes that satisfy molecular Koch's postulates are often referred to as virulence factors. The postulates were formulated by the microbiologist Stanley Falkow in 1988 and are based on Koch's postulates.[1]

The postulates as originally described by Dr. Falkow are as follows:

  1. "The phenotype or property under investigation should be associated with pathogenic members of a genus or pathogenic strains of a species." Additionally, the gene in question should be found in all pathogenic strains of the genus or species but be absent from nonpathogenic strains[citation needed].
  2. "Specific inactivation of the gene(s) associated with the suspected virulence trait should lead to a measurable loss in pathogenicity or virulence." Virulence of the microorganism with the inactivated gene must be less than that of the unaltered microorganism in an appropriate animal model.
  3. "Reversion or allelic replacement of the mutated gene should lead to restoration of pathogenicity." In other words, reintroduction of the gene into the microbe should restore virulence in the animal model.
  4. "The gene, which causes virulence, must be expressed during infection."
  5. "Immunity must be protective."

For many pathogenic microorganisms, it is not currently possible to apply molecular Koch's postulates to a gene in question. Testing a candidate virulence gene requires a relevant animal model of the disease being examined and the ability to genetically manipulate the microorganism that causes the disease. Suitable animal models are lacking for many important human diseases. Additionally, many pathogens cannot be manipulated genetically.

References

  1. ^ Falkow S (1988). "Molecular Koch's postulates applied to microbial pathogenicity." Rev Infect Dis 10(suppl 2):S274-S276.



Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Koch's postulates — are four criteria designed to establish a causal relationship between a causative microbe and a disease. The postulates were formulated by Robert Koch and Friedrich Loeffler in 1884 and refined and published by Koch in 1890. Koch applied the… …   Wikipedia

  • Stanley Falkow — Stanley Falkow, PhD, is microbiologist and a professor of microbiology and immunology at Stanford University School of Medicine.National Institute of Allergy and Infectious Diseases [http://www3.niaid.nih.gov/labs/aboutlabs/lhbp/officeOfTheChief/f… …   Wikipedia

  • Bacteria — Taxobox color = lightgrey name = Bacteria fossil range = Archean or earlier Recent image width = 210px image caption = Escherichia coli image is 8 micrometres wide. domain = Bacteria subdivision ranks = Phyla [cite web… …   Wikipedia

  • Infectious disease — Classification and external resources A false colored electron micrograph shows a malaria sporozoite migrating through the midgut epithelia. ICD 10 …   Wikipedia

  • Microorganism — Microbe redirects here. For other uses, see Microbe (disambiguation). A cluster of Escherichia coli …   Wikipedia

  • Timeline of peptic ulcer disease and Helicobacter pylori — This is a timeline of the events relating to the discovery that peptic ulcer disease is caused by H. pylori . In 2005, Barry Marshall and Robin Warren were awarded the Nobel Prize in Physiology or Medicine for their discovery that peptic ulcer… …   Wikipedia

  • Duesberg hypothesis — The Duesberg hypothesis is the claim, associated with University of California, Berkeley professor Peter Duesberg, that various non infectious factors such as recreational and pharmaceutical drug use are the cause of AIDS, and that HIV (human… …   Wikipedia

  • Oncovirus — An oncovirus is a virus that can cause cancer. This term originated from studies of acutely transforming retroviruses in the 1950–60s, often called oncornaviruses to denote their RNA virus origin. It now refers to any virus with a DNA or RNA… …   Wikipedia

  • Bacteria — Para otros usos de este término, véase Agrupación de Electores BACTERIA …   Wikipedia Español

  • Microbiology — An agar plate streaked with microorganisms …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”