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Microbiology as a Science

Prepared by Dr. Jhason John J. Cabigon

1. Microbiology

a. Study of microorganisms

b. Application of techniques - such as sterilization and the use of culture

media - that are necessary for the successful isolation and growth ofmicroorganisms.

2. Microorganism

a. Very small organisms:i. Living things which individually are too small to be seen with the

naked eye.

ii. Something studied using characteristic techniques including:

1. aseptic technique2. pure culture technique

3. microscopic observation of whole organisms

b. All of the following may be considered microorganisms:

i. bacteria (eubactera, archaebacteria)ii. fungi (yeasts, molds)

iii. protozoaiv. microscopic algae

v. viruses

vi. various parasitic worms*

3. Relevance of Microbiology

a. Microbes live on and in our bodies

- indigenous or normal microflora/microbiota (beneficial)

- approximately 10 times as many microorganisms as the total number of

cells- 500 to 1000 different species live on and in us

b. Some microbes are opportunists

- when they gain access to a part of our anatomy where they do not belong- when a person becomes stressed out or debilitated

- prolonged antibiotic use can reduce the normal flora

c. Microbes are essential for life- algae and cyanobacteria produce more oxygen than plants

- endosymbiotic bacteria inside cells

d. Microorganisms are involved in the decomposition of dead organisms- decomposers/saprophytes break down dead and dying organic materials

into nitrates, phosphates, and other chemicals necessary for the growth

of plants.e. Microbes are capable of decomposing industrial waste

- bioremediation and genetic engineering

f. Many microorganisms are involved in elemental cycles

- microbial ecology; i.e. conversion of nitrogen gas to ammonia, then tonitrites and nitrates

g. Algae and bacteria serve as food for tiny animals

http://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#bacteria%23bacteriahttp://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#fungi%23fungihttp://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#protozoa%23protozoahttp://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#algae%23algaehttp://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#virus%23virushttp://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#bacteria%23bacteriahttp://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#fungi%23fungihttp://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#protozoa%23protozoahttp://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#algae%23algaehttp://www.mansfield.ohio-state.edu/~sabedon/biol2005.htm#virus%23virus

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- serving as the starting point of many food chains

h. Some microorganisms live in the intestinal tracts of animals

- Vitamin K and B1-producing bacteria- Cellulose-eating protozoa in termites

i. Many microorganisms are essential in various food and beverage industries

- biotechnology or industrial microbiology; i.e. cheese, beer andantibiotics

j. Microbes are essential in the field of genetic engineering

- gene from one organism is inserted into a bacterial or yeast cell forproduction of a gene product, i.e. insulin, GH, interferons, vaccines

k. Microbes have been used as cell models

- by studying microbes, scientists have learned a great deal about working

cellsl. Microorganisms cause diseases

- pathogens germs; disease-causing microorganisms (microbial

enemies); only 3% of known microbes

- infectious diseases and microbial intoxication- infectious diseases are the leading cause of death in the world

3. History of Microbiology

First Microorganisms primitive microorganisms found in ancient rock

formations in Northwestern Australia date back to about 3.5 billion years ago.

Earliest Known Infectious Disease pestilence in Egypt on 3180 BC

Concept of Spontaneous Generation

(i) The "spontaneous" clouding of clear broth

(ii) The occurrence of maggots on meatGerm Theory

(i) Diseases may be caused by microscopic organisms(ii) Microorganisms were not spontaneously generated

a. Anton Van Leeuwenhoek father of Microbiology; at some time before1668, He learned to grind lenses;invented Single-lens or SimpleMicroscope magnifying up to 200-300x; He was the first to observe

individual, live microorganisms.

b. Louis Pasteur contributions are considered to be the foundation ofmicrobiology and cornerstone of modern medicine

Pasteur showed that boiled broth did not become cloudy (turbid) whenair but not dust could contact the broth

Built elegant "swan-necked" flasks which trapped dust (and

microorganisms) along their curved necks, thus showing that neither

air nor broth were sufficient to allow the generation of microorganisms

(it is the microorganisms, e.g., bacteria, that scatter light therebyproducing turbidity in broth cultures)

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Pasteur additionally showed that cotton plugs (a primitive air-filtration

device) could prevent microbes from reaching otherwise air-exposed

sterile broths

Note that Pasteur was fortunate that the foods he boiled into broths did

not contain bacterial spores since such spores are resistant to killing by

boiling Pasteur invented pasteurization, the heating of foods to eliminate

harmful microorganisms while retaining not-harmful microorganisms

Introduced Aerobes and Anaerobes

He was responsible for the association of specific microbes with

diseases

He development the rabies vaccine (as well as other vaccines)

c. Robert Koch father of modern bacteriology

Identified thebacteriathat cause anthrax, tuberculosis, cholera

Contributed significantly to the development ofpure culture technique

Introduction ofagarto microbiology

Koch's Postulates, a way of ascribing a particularinfectious disease to

a particular, causing microorganism

Kochs postulates:

A specific organism must be always observed in association with the

disease.

The organism must be isolated from an infected host and grown in

pure culture in the laboratory.

When organisms from the pure culture are inoculated into a

susceptible host organism, it must cause the disease.

The infectious organism must be reisolated from the diseased

organism and grown in pure culture.

d. Hans Jansen developed the first compound microscope; only 3-9xmagnifications

e. Robert Hooke 3-lens-compound microscope; coined the term cells.

f. Theodore Schwann and Matthias Schleiden around 1838-1839, theyconcluded that all plant and animals were composed of cells

g. Rudolf Virchow biogenesis; Life comes from pre-existing life; cells

come from pre-existing cells

Other contributors:

a. Francesco Redi showed that meat protected from flies via a gauzebarrier did not develop maggots, hence were not spontaneously generated

b. Ignaz Semmelweis (mid-late 1800s) aseptic technique

c. Joseph Lister(mid-late 1800s) father of aseptic surgery

d. Edward Jenner(late 1700s) - use of cowpox virus to vaccinate againstsmallpox virus

e. Alexander Fleming (early 1900s) - discovered penicillin

http://www.mansfield.ohio-state.edu/~sabedon/black01.htm#bacteria%23bacteriahttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#bacteria%23bacteriahttp://www.mansfield.ohio-state.edu/~sabedon/biol4035.htm#pure_culture_techniquehttp://www.mansfield.ohio-state.edu/~sabedon/black06.htm#solid_mediumhttp://www.mansfield.ohio-state.edu/~sabedon/black14.htm#kochs_postulatehttp://www.mansfield.ohio-state.edu/~sabedon/black14.htm#infectious_diseasehttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#microorganisms%23microorganismshttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#redi_francesco%23redi_francescohttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#semmelweis_ignaz%23semmelweis_ignazhttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#lister_joseph%23lister_josephhttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#jenner_edward%23jenner_edwardhttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#flemming_alexander%23flemming_alexanderhttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#bacteria%23bacteriahttp://www.mansfield.ohio-state.edu/~sabedon/biol4035.htm#pure_culture_techniquehttp://www.mansfield.ohio-state.edu/~sabedon/black06.htm#solid_mediumhttp://www.mansfield.ohio-state.edu/~sabedon/black14.htm#kochs_postulatehttp://www.mansfield.ohio-state.edu/~sabedon/black14.htm#infectious_diseasehttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#microorganisms%23microorganismshttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#redi_francesco%23redi_francescohttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#semmelweis_ignaz%23semmelweis_ignazhttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#lister_joseph%23lister_josephhttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#jenner_edward%23jenner_edwardhttp://www.mansfield.ohio-state.edu/~sabedon/black01.htm#flemming_alexander%23flemming_alexander

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4. Branches of Microbiology

A. Bacteriology

B. PhycologyC. Protozoology

D. Mycology

E. VirologyOther Fields of Microbiology

A. Agricultural Microbiology

B. BiotechnologyC. Environmental Microbiology and Bioremediation

D. Medical and Clinical Microbiology

E. Microbial Genetics and Genetic Engineering

F. Microbial PhysiologyG. Pleomicrobiology

H. Parasitology

I. Sanitary Microbiology

J. Veterinary Microbiology