Talk:Microorganism: Difference between revisions

From Citizendium
Jump to navigation Jump to search
imported>David Tribe
imported>David Tribe
Line 39: Line 39:


=== Discovery ===
=== Discovery ===
Before [[Anton van Leeuwenhoek]]'s [http://www.sciences.demon.co.uk/wav-mics.htm invention of the microscope] and discovery of microorganisms with it in 1676, it had been a mystery as to why [[grapes]] could be turned into [[wine]], [[milk]] into [[cheese]], or why food would spoil. Leeuwenhoek did not make the connection between these processes and microorganisms, but he did establish that there were forms of life that were not visible to the naked eye. Leeuwenhoek's discovery, along with subsequent observations by [[Lazzaro Spallanzani]] and [[Louis Pasteur]], ended the long-held belief that life could [[Abiogenesis|spontaneously appear]] from non-living substances.
Before [[Anton van Leeuwenhoek]]'s [http://www.sciences.demon.co.uk/wav-mics.htm invention of the microscope] and discovery of microorganisms with it in 1676, [[Lazzaro Spallanzani]] and [[Louis Pasteur]], ended the long-held belief that life could [[Abiogenesis|spontaneously appear]] from non-living substances.


Spallanzani found that microorganisms could only settle in a broth if the broth was exposed to the air; he also found that boiling the broth would sterilise it, killing the microorganisms. Pasteur expanded upon these findings by exposing boiled broths to the air in vessels that contained a filter to prevent all particles from entering, or in vessels with no filter but with air being admitted via a curved tube that would not allow dust particles to come into contact with the broth. By first boiling the broth, Pasteur ensured that there were no microorganisms alive in the broths at the start of his experiment. Nothing grew in the broths during his experiments, showing that the living organisms that grew in such broths came from outside, as [[spore]]s on dust, rather than spontaneously generated within the broth. Thus, Pasteur decisively refuted the theory of spontaneous generation and supported [[Germ theory of disease|germ theory]].
Spallanzani found that microorganisms Pasteur ensured that there were no microorganisms alive in the broths at the start of his experiment. Nothing grew in the broths during his experiments, showing that the living organisms that grew in such broths came from outside, as [[spore]]s on dust, rather than spontaneously generated within the broth. Thus, Pasteur decisively refuted the theory of spontaneous generation and supported [[Germ theory of disease|germ theory]].


In 1876, [[Robert Koch]] showed that microbes can cause disease, by showing that the blood of cattle that were infected with [[anthrax]] always contained large numbers of [[Bacillus anthracis]]. Koch also found that he could transmit anthrax from one animal to another by taking a small sample of blood from the infected animal and injecting it into a healthy one, causing the healthy animal to become sick. He also found that he could grow the bacteria in a nutrient broth, inject it into a healthy animal, and cause illness. Based upon these experiments, he devised criteria for establishing a causal link between a microbe and a disease in what are now known as [[Koch's postulates]]. Though these postulates are no longer strictly accurate, they remain historically important in the development of scientific thought.
In 1876, [[Robert Koch]] showed that microbes can cause disease, by showing that the blood of cattle that were infected with [[anthrax]] always contained large numbers of [[Bacillus anthracis]].[[Koch's postulates]]. Though these postulates are no longer strictly accurate, they remain historically important in the development of scientific thought.


[[Image:Tree_phylogeny_3_domain.gif|thumb|300px|left|A [[phylogenetic tree]] of life based on differences in [[rRNA]], showing the separation of [[bacteria]], [[archaea]], and [[eukaryote]]s.]]
[[Image:Tree_phylogeny_3_domain.gif|thumb|300px|left|A [[phylogenetic tree]] of life based on differences in [[rRNA]], showing the separation of [[bacteria]], [[archaea]], and [[eukaryote]]s.]]

Revision as of 07:42, 17 March 2007

The gap from Leeuwenhoek to Pasteur is a very long one. When L is mentioned, Would it be better to talk about why L. did do than what he did not.?DavidGoodman 21:02, 24 November 2006 (CST)

The statments that visible /invisible have exceptions occurs at least 5 times, 1 in each section.
The section on eukaryotic microorganisms neeeds to specifiy just what is included--a good trick--(my first research exerience was in protozoology, as it was then called). As you undoubtedly intend to include fungi, you'll have to explain that they are not plants. We should probably do a fngii article fairly early on. I'll start one from WP.DavidGoodman 20:51, 25 November 2006 (CST)


Complete rewrite

I think this article starts badly and is boring bland. I propose to start from scratch and De WP edia it. This will take time. I will do it so that access to the current one is preserved. An I am giving fair notice, in case there is disagreement. Im the only one to edit it here anyway. David Tribe 07:29, 17 March 2007 (CDT)

NEW DRAFT OF ARTICLE

Filaments of joined cells the cyanbacterium Anabaena magnified about 4,000 times. In this prokayotic organism there are two types of cell. The occcasional cells that have a distinct appearance are 'heterocysts', specialized to fix nitrogen gas. Cooperation among Microorganisms Ned S. Wingreen, Simon A. Levin PLoS Biol 4(9): e299. DOI:10.1371/journal.pbio.0040299 2006


Some unicellular protists and unusually large bacteria (Epulopiscium fishelsoni and Thiomargarita namibiensis) are visible to the naked eye [1]

The study of micro-organisms is called microbiology.

Importance

Habitats and ecology

Extremophiles

Use in food

[2]

Use in science

Microorganisms and human health

Infectious disease

Hygiene

History

Evolution

Discovery

Before Anton van Leeuwenhoek's invention of the microscope and discovery of microorganisms with it in 1676, Lazzaro Spallanzani and Louis Pasteur, ended the long-held belief that life could spontaneously appear from non-living substances.

Spallanzani found that microorganisms Pasteur ensured that there were no microorganisms alive in the broths at the start of his experiment. Nothing grew in the broths during his experiments, showing that the living organisms that grew in such broths came from outside, as spores on dust, rather than spontaneously generated within the broth. Thus, Pasteur decisively refuted the theory of spontaneous generation and supported germ theory.

In 1876, Robert Koch showed that microbes can cause disease, by showing that the blood of cattle that were infected with anthrax always contained large numbers of Bacillus anthracis.Koch's postulates. Though these postulates are no longer strictly accurate, they remain historically important in the development of scientific thought.

A phylogenetic tree of life based on differences in rRNA, showing the separation of bacteria, archaea, and eukaryotes.

Classification

Bacteria

Escherichia coli magnified approx. 14,000 fold by transmission electron microscopy. The filamentous structures are flagella. CDC/Elizabeth H. White, M.S PLoS Biol. 2006 January; 4(1): e13. Published online 2005 December 20. doi: 10.1371/journal.pbio.0040013


Archaea

Protists

Fungi

Microorganisms in fiction

Microorganisms have frequently played an important part in science fiction, both as agents of disease, and as entities in their own right. Some notable uses of microorganisms in fiction include:

References

Citations

  1. ↑ Annu Rev Microbiol. 2001;55:105-37. Big bacteria. Schulz HN, Jorgensen BB.
  2. ↑ Dairy Microbiology. University of Guelph. Retrieved on 2006-10-09.

Further reading

  • Dixon, Bernard (1994). Power Unseen: How Microbes Rule the World, 1st ed.. W. H. Freeman, Oxford and New York. ISBN 0-7167-4504-6. 
  • Krasner, Robert I. (2002). The Microbial Challenge: Human-Microbe Interactions, 1st.. ASM Press, Washington, DC. ISBN 0-13-144329-4. 
  • Knoll, Andrew H. (2003). Life on a Young Planet: the First Three Billion Years of Evolution on Earth, 1st ed.. Princeton University Press. ISBN 0-691-00978-3. 
  • Postgate, John (1992). Microbes and Man, 3rd ed.. Cambridge University Press, UK. ISBN 0-521-42355-4. 

External links

Retrieved from "https://citizendium.org/wiki/index.php?title=Talk:Microorganism&oldid=105768"