History of Cell Biology

History of Cell Biology

• The naked eye can see up to just smaller than 1mm

• Light microscopes can see from around 0.5cm to 100nm (including plant cells, human cells and bacteria)

• Electron microscopes can see from around 0.5cm to 1A (including viruses, proteins and atoms)

• Standard form is useful when using sizes and numbers of microorganisms

• Bacteria
  • Study: Bacteriology
  • Organisms: Unicellular
• Yeasts and Moulds
  • Study: Mycology
  • Organisms: Unicellular to multicellular
• Protozoa
  • Study: Protozoology
  • Organisms: Unicellular
• Viruses
  • Study: Virology
  • Organisms: Non-cellular

• Spontaneous Generation Controversy
  • Aristotle (384-322): living organisms can develop from non-living materials
  • Organsims do not need a descendant
• 1676: Anton van Leeuwenhoek was the first person to observe microorganisms at 200x magnifaction: 'very little animacules in fresh water'
  • Approximate sizes: bacteria ~3um, viruses ~0.03um
• 1861: Louis Pasteur's Swan-necked flasks
  • Proved that microorganisms do not arise by spontaneous generation

• 1847: Ignaz Semmelweiss: Hungarian physician - doctors in Vienna hospitals spreading childbed fever while delivering babies. Forced doctors under his supervision to wash their hands before touching patients
• 1857: Louis Pasteur proposed the 'germ theory' of disease
• 1867: Joseph Lister introduced antiseptics in surgery
• 1876: Rober Kock: German bacteriologist - cultivated anthrax bacteria outside the body using blood serum at body temperature
  • 'Koch's postulates' (1884): the critical test for the involvement of a microorganism in a disease

• The agent must be constantly present in every case of the disease but absent from healthy individuals

• The agent must be isolated and cultured in vitro and away from the animal body

• The disease must be reproduced when a pure culture of the agent is inoculated into a susceptible host

• The same agent must be recoverable from the experimanetally infected host

• With Walter Hesse discovered solid culture media

• Agar: Polysaccharide derived from red algae

• 1882: Tuberculosis: isolation and staining of M.Tuberculosis bacteria and proof that this causes tuberculosis 

• Discovery and isolation of Vibrio cholerae

• 1887: Richard Petri - Petri dish

• Edward Jenner (1798): Persons exposed to cows often developed a mild form of pox but then never got smallpox
  • spread cowpox by inoculating with material from pustules
  • found that this created immunity to smallpox
• Louis Pasteur (1880): Immunised a chicken
  • Method of attenuating (weakening) a virulent pathogen, the agent of chicken cholera, so it would immunise and not cause disease
• 1960: Oral polio vaccine approved in the USA: Albert Sabin
• 1979: Smallpox vaccine officially eliminated smallpox
• 2008: HPV vaccine introduced to the UK

• Discovered much later than bacteria
• One single physiochemical characteristic was measured - small size assessed by filterability - viruses are much smaller than bacteria

• 1899: Reed and Caroll: Yellow fever virus: First demonstration that virus causes human disease
• 1976: Bishop and Varmus: Identify same oncogenes in virus and animals (oncogene = cancer forming gene)
• 1983: Luc Montadnier and Robert Gallo: Discovered HIV

• Carl Linnaeus (1707-1778): Father of Taxonomy
  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus 
  • Species
• Genus and species make up scientific name

• Antibiotic resistance is one of the biggest threats to global health, food security and development today
• Antibiotic resistance can affect anyone, of any age, in any country
• Antibiotic resistance occurs naturally, but misuse of antibiotics in humans and animals is accelarating the process
• A growing number of infection, e.g. pneumonia, tuberculosis, gonorrhoea and salmonella, are becoming harder to treat as the antibiotics used to treat them become less effective
• Antibiotic resistance leads to longer hospital stays, higher medical costs and increased mortality