Introduction to Biotechnology

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BIOL 3340


Chapter 1








The History







and






Scope of Microbiology

The Importance of
Microorganisms


medical and most populous group of
organisms and are found everywhere on
the planet


play a major role in recycling essential
elements


source of nutrients and some carry out
photosynthesis


benefit society by their production of food,
beverages, antibiotics and vitamins


causative agents of some important
diseases


What is Microbiology?


generally defined as the study of
organisms too small to be clearly seen by
the unaided eye (i.e.,

microorganisms
)


these organisms are relatively simple in
their construction and lack highly
differentiated cells and distinct tissues


Members of the Microbial World



procaryotic

cells
lack a true membrane
-
delimited nucleus


eucaryotic

cells
have a membrane
-
enclosed nucleus, are more complex
morphologically and are usually larger
than
procaryotic

cells

Procaryotes


most are single
-
celled


most have
peptidoglycan

in cell wall


can survive broad range of environments


most are non
-
pathogenic and play major
role in nutrient recycling

……..
Eucaryotes


animals, plants and
eucaryotic

microorganisms


microorganisms include
protists

(unicellular algae, protozoa, slime molds
and water molds) and fungi


most are larger than
procaryotic

cells


…….. Viruses


acellular


smallest of all microbes (smallest is 10,000
times smaller than a typical bacterium

Importance of Microorganisms


first living organisms on planet


live almost everywhere life is possible


more numerous than any other kind of
organisms


global ecosystem depends on their
activities


influence human society in many ways

Discovery of Microbes

Antony van Leeuwenhoek (1632
-
1723)


first person to observe and describe
microorganisms accurately


Developed early microscope


First to
observemicrobes
:“animalcules”


……..
The Conflict over
Spontaneous Generation



Spontaneous generation: living
organisms can
develop from
nonliving
or decomposing matter


1. Francesco
Redi

(1626
-
1697):


disproved spontaneous generation for large
animals


showed that maggots on decaying meat
came from fly eggs


2. John Needham (1713
-
1781):


his experiment : mutton broth in flasks


boiled

sealed with cork :



broth became cloudy & contained
microorganisms

3. Lazzaro Spallanzani (1729
-
1799):



his experiment: boiled seeds in flasks &
water

sealed


boiled:



no growth of microorganisms in sealed &
open flasks had animicules

……..
Louis Pasteur (1822
-
1895)

4. Pasteur



Mid to late
-
1800s



French chemist and a “founder” of the
modern science of microbiology



Settled the Spallanzani
-
Needham debate
with the “swan
-
necked flask” experiment
& put to rest the
Spontaneous generation
theory



boiled the solutions &
left flasks
exposed to air


results: no growth of microorganisms


placed nutrient solution in flasks with
long, curved necks



……..
Pasteur

……..
Pasteur




……..
Pasteur




Pasteur laid the foundation of aseptic
techniques, techniques that prevent
contamination by unwanted microbes. These
techniques are based on Pasteur’s idea that
microbes can be killed by heat and that
procedures can be designed to inhibit the access
of airborne microbes to nutrient environment.




He
dispprove

the idea that microorganisms
spontaneously generated from non
-
living matter
through mystical forces is one of the greatest
contributions of Pasteur in science




Final Blow to Theory of
Spontaneous Generation


5.

John Tyndall (1820
-
1893):



demonstrated that dust carries microorganisms



showed that if dust was absent, nutrient broths
remained sterile, even if directly exposed to air



Demonstrated directly that the growth of
microbes in contaminated flasks was due to
microbial cells from airborne dust particles, not
from spontaneous generation


Theory of biogenesis Vs Spontaneous
generation :


The theory of biogenesis states that
living things can only arise from living
things and cannot be spontaneously
generated.


The Spontaneous generation hypothesis
proposed by scientists to explain the
origin of the “animalcules” observed by
Antoni van Leeuwenhoek in his
magnifying lenses had received wide
acceptance all over Europe from Antoni’s
time until the time of Louis Pasteur
.

The Golden Age of Microbiology
(1857
-
1914)


Many disease producing organisms were
discovered


Microbial metabolism studies undertaken


Microbiological techniques refined


A better understanding of the role of
immunity and ways to control and prevent
infection by microbes

The Role of Microorganisms in
Disease



was not immediately obvious



establishing connection depended on
development of techniques for studying
microbes



once established, led to study of host
defenses
-

immunology

Recognition of the Relationship
between Microorganisms and
Disease



Agostini

Bassi

(1773
-
1856):

showed that a disease of silkworms was caused by
a fungus



M. J. Berkeley (ca. 1845):

demonstrated that the great Potato Blight of
Ireland was caused by a water mold

Heinrich de Bary (1853):

showed that smut and rust fungi caused cereal
crop diseases

Louis Pasteur :

showed that the p
ébrine disease of silkworms
was caused by a protozoan

Other evidences


Joseph Lister:


provided indirect evidence that
microorganisms were the causal agents of
disease



developed a system of surgery designed to
prevent microorganisms from entering wounds
as well as methods for treating instruments and
surgical dressings



his patients had fewer postoperative infections

Robert Koch (1843
-
1910)

Robert Koch:




Established the relationship between
Bacillus anthracis

and anthrax



Develop the
Koch’s postulates:


used today to establish the link between a
particular microorganism and a particular
disease

..Koch Postulates

1.Similar pathogen must be present in every case of
the disease.

2.
The pathogen should be isolated from the
diseased animal host and grown in pure culture.

3.
A healthy laboratory animal inoculated with the
pathogen taken from the pure culture must acquire
the disease.

4.
The pathogen must be isolated from the
inoculated animal and should be the same from the
microbe in the original animal.


The Development of Techniques
for Studying Microbial Pathogens


Koch’s work led to discovery or
development of:


agar


petri

dish


nutrient broth and nutrient agar


methods for isolating microorganisms


Immunological Studies

Edward Jenner (ca. 1798)



used a vaccination procedure to protect
individuals from smallpox



Pasteur and Roux :



discovered that incubation of cultures for long
intervals between transfers caused pathogens to lose
their ability to cause disease


Pasteur and his coworkers

developed vaccines for chicken cholera, anthrax, and
rabies


Emil von Behring (1854
-
1917) and
Shibasaburo

Kitasato

(1852
-
1931)


developed antitoxins for diphtheria and
tetanus


evidence for
humoral

immunity


Elie

Metchnikoff (1845
-
1916)


discovered bacteria
-
engulfing,
phagocytic

cells in the blood


evidence for cellular immunity

The Development of Industrial
Microbiology and Microbial
Ecology


Louis Pasteur



demonstrated that alcohol
fermentations and other fermentations
were the result of microbial activity


developed the process of pasteurization
to preserve wine during storage


Additional Developments


Sergei
Winogradsky

(1856
-
1953) and
Martinus

Beijerinck

(1851
-
1931)


studied soil microorganisms and
discovered numerous interesting
metabolic processes (e.g., nitrogen
fixation)


pioneered the use of enrichment
cultures and selective media


Aseptic techniques


……..
Pure Culture Technique


Bibliography


http://en.wikipedia.org/wiki/Scientific_
method


http://www.brighthub.com/science/me
dical/articles/21169.aspx


https://files.kennesaw.edu/faculty/jhend
rix/bio3340/home.html


Lecture
PowerPoints

Prescott’s Principles
of Microbiology
-
Mc
Graw

Hill Co.