Microbiology 155 Chapter 1

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Feb 20, 2013 (4 years and 1 month ago)

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Basic Microbiology

An Introduction to the World of Microbiology

1. Archaea

Archaea


Extremophiles
-
Very small bacteria
that are adapted to extreme conditions

Thermophiles
-

extreme heat

Psychrophiles


Cold( ice caps)

Halophiles


high concentrations of salt

Methanogens


live in a hostile environment and
produce methane gas as a by product of their
life style

Sulfur loving bacteria


live in high
concentrations of sulfurous gases


2. Bacteria


Eubacteria


True bacteria


Includes
environmental bacteria such as nitrogen
fixing bacteria and bacteria of decay
and decomposition as well as pathogens.


Cyanobacteria


Formerly known as blue
green algae


small, unicellular algae
found in ponds, lakes, streams, and the
ocean. Essential to the web of life

Prokaryote cells



Are very small and undifferentiated



Lack a nuclear membrane



Lack cellular organelles like
mitochondria



Have unique cell walls and cell
membranes



Have only one circular chromosome

Bacterial Growth= Cell Division

Binary fission

Bacterial cells can be seen with a
light microscope or an electron
microscope

3. Eukarya


Includes


Protozoans


Algae


Fungi


Animals and Plants

Historical Roots of Microbiology

1660: Robert Hooke (1635
-
1703) published "Micrographia", containing
drawings and detailed observations of biological materials made with the
best compound microscope and illumination system of the time.

1676: Anton von Leeunhoek (1632
-
1723) was the first person to observe
microorganisms.

1883: Carl Zeiss pioneered developments in microscopy (such as immersion
lenses and apochromatic lenses which reduce chromatic aberration) which
perist until the present day.

1931: Ernst Rusko
-
constructed the first electron microscope.

1688: Francesco Redi (1626
-
1678) was an Italian physician who
refuted the idea of
spontaneous generation

by showing that
rotting meat carefully kept from flies will not spontaneously
produce maggots.

1836: Theodor Schwann (1810
-
1882) helped develop the cell
theory of living organisms, namely that that all living organisms
are composed of one or more cells and that the cell is the
basic functional unit of living organisms.

1861: Louis Pasteur (1822
-
1895) famous experiments with
swan
-
necked flasks finally proved that microorganisms do not
arise by spontaneous generation.


Redi’s
Experiment

Edward Jenner

1546: Hieronomus Fracastoro (Girolamo Fracastoro) wrote "On
Contagion" ("De contagione et contagiosis morbis et curatione"), the
the first known discussion of the phenomenon of contagious infection.

1835 Agostino Bassi de Lodi showed that a disease affecting silkworms
was caused by a fungus
-

the first microorganism to be recognized as a
contagious agent of animal disease.

1847: Ignaz Semmelweis (1818
-
1865), a Hungarian physician who
decided that doctors in Vienna hospitals were spreading childbed
fever while delivering babies. He started forcing doctors under his
supervision to wash their hands before touching patients.

1857: Louis Pasteur proposed the "germ theory" of disease.

1867: Joseph Lister (1827
-
1912) introduced antiseptics in surgery. By
spraying carbolic acid on surgical instruments, wounds and dressings,
he reduced surgical mortality due to bacterial infection considerably


Lister’s Carboxylic spray

Sterile Surgery

Pasteur Fermentation

Beer and Bread

1876: Robert Koch (1843
-
1910). German bacteriologist was the first
to cultivate anthrax bacteria outside the body using blood serum
at body temperature. Building on pasteur's "germ theory", he
subsequently published





"
Koch's postulates
" (1884), the critical test for the involvement of a
microorganism in a disease:

The agent must be present in every case of the disease.

The agent must be isolated and cultured in vitro.

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

The agent must be recoverable from the experimentally
-
infected
host.



Fields of Microbiology

Bacteriology

Virology

Epidemiology

Immunology

Parasitology

Protozoology

Mycology

Virology



Recombinant DNA technology and
genetic engineering


Biotechnology

Modern Microbiology