Breve Historia de la Microbiología.wmv
A Brief History of Microbiology
Introduction to Microbiology
- The presentation aims to provide a concise history of microbiology, emphasizing its significance in medicine and encouraging further research into the field.
Early Developments in Microbiology
- Microbiology studies organisms invisible to the naked eye, requiring special instruments for observation. The development of this science is divided into four main periods.
Speculative Period (Antiquity to 1546)
- Girolamo Fracastoro introduced the concept of disease-causing "seeds" in his book De contagione et contagiosis morbis.
- The first microscope was mentioned by Cornelius Drebbel, marking the beginning of microscopic observation.
Accumulation of Observations (1675 - Mid 19th Century)
- Anton van Leeuwenhoek improved magnifying lenses and created structures resembling microscopes, allowing him to observe tiny objects up to 300 times their size.
- Robert Hooke discovered filamentous fungi and published Micrographia, which included detailed drawings and introduced the term "cell."
Cultivation of Microorganisms (Mid 19th Century)
- This period saw advancements in isolating microorganisms; Robert Koch was pivotal in developing solid media for culturing bacteria.
- Koch's collaborator Walter Hess suggested using agar as a solidifying agent, leading to successful cultivation methods.
Key Contributions and Discoveries (Late 19th Century - Early 20th Century)
- Frederick Gustav Henle contributed significantly with his work on tuberculosis postulates, which were later published by Koch.
- The Gram staining technique was developed by Hans Christian Gram in 1884 for differentiating bacterial types based on cell morphology.
Advancements from the Early 20th Century
- Significant progress occurred across various microbiological branches: parasitology, virology, immunology, and bacteriology.
Notable Discoveries
- Walter Reed confirmed that yellow fever is transmitted by mosquitoes rather than direct contact, revolutionizing epidemiology.
- Félix d'Hérelle discovered bacteriophages between 1915 and 1917; these viruses specifically target bacteria.
- Alexander Fleming discovered penicillin in September 1928 when he observed mold contaminating bacterial cultures.
Observations on Bacterial Colonies and Penicillin
Discovery of Penicillium Notatum
- Áureos Fleming observed bacterial colonies near a fungus later identified as Penicillium notatum, noting that the colonies were transparent due to bacterial lysis.
- Penicillium is a mold that produces a natural substance with antibacterial effects, leading to the discovery of penicillin.
Classification of Organisms
- Edward Pierre León Chatón, a French naturalist and marine biologist, distinguished between eukaryotic organisms (with nuclei) and prokaryotes (without nuclei), coining these terms in his 1925 publication.
- This classification highlights the complexity of life forms, with implications for understanding parasitism.
Viroids: A New Form of Parasitism
- In 1974, viroids were discovered as infectious agents with minimal genetic complexity, representing an extreme form of parasitism.
- Viroids consist solely of covalently closed single-stranded RNA molecules and are characterized by their low molecular weight.
Unique Bacteria: Thiomargarita Namibiensis
- Thiomargarita namibiensis is a large Gram-negative proteobacteria found in ocean sediments off Namibia, notable for its size—up to 750 mm long—making it visible to the naked eye.
- Discovered by Heid Schulz in 1999, this species has close relatives found in the Gulf of Mexico as well.