Microbiology

Microbiology

Chapter 1

Part I

Introduction to Microbiology

Scope of Microbiology


Microbes


Life forms which require magnification for
viewing


Ubiquitous


Each group has a distinct set of biological
characteristics


Single celled vs. multi
-
celled


Prokaryotic vs. eukaryotic


Cell wall vs. no cell wall


Autotrophic vs. heterotrophic


Cellular vs. acellular

Prokaryotic vs. Eukaryotic

Assigning Characteristics


Bacteria



Protozoa



Fungi



Algae



Helminths



Viruses

Assign common characteristics to each group

(Top) Coccidioidomycosis Arthrospores

(Bottom) Development of Arthrospores

Into spherule in lung tissue

Fungal Infection of the lung

Schistosoma (worms) at

two different stages of

development
–

liver

Disease and other symptoms

Staphylococcus Aureus

Gram positive bacteria

Staph infections and MRSA

Trypanosoma

Eukaryotic pathogen

African Sleeping Sickness

Treponema pallidum

Bacterial spirochete

Causes syphilis

Mycobacterium tuberculosis. Acid
fast bacteria (shown in pink) like
this causes TB and leprosy. Light
blue is Staph epi, a common

bacteria cocci which inhabits the

Skin. Not a common pathogen


Herpes Virus

Size
Comparisons

What Do

Microbes Do?

Photosynthesis

Decomposition

Soil Fertility

&

Microbial

Ecology

Microbial

Physiology &

Fermentation of

Cheese

Wine

Bread

Genetics,

Gene

Regulation

&

Biotechnology

Bioremediation

Oil Eating

Bacteria &

Fungi

Water

Purification

Infectious

Disease

&

Immunology

Ch 4, 7, & 26

Ch 8 & 27

Ch 9 & 10

Ch 27 Briefly

Need an

Environmental

& Applied

Micro

Course

Ch 14
–

16

&

Ch 18
-

25

Part II

Historical Figures in
Microbiology

Superstition of Microbiology


Spontaneous generation


For thousands of years people believed that
living things arose from vital forces present in
non living matter


Mushrooms appearing on rotting wood


Afflicted people were thought to be cursed


Controversy between…


Abiogenesis and biogenesis


First Look at Microbes


In the 1600s



Robert Hooke (English)
reported that living things
were composed of little
boxes or cells


Antonie van Leeuwenhoek
construction microscopes
which could magnify 300X


Described microorganisms that
he observed in teeth scrapings
& rain water

Abiogenesis vs. Biogenesis


Franceso Redi


He wanted to ascertain whether maggots arose
from some “vital force” of the meat or were
offspring of flies

Abiogenesis vs. Biogenesis


Conclusions of Redi’s Experiment


This and related experiments proved that
complex animals such as insects and mice
develop through biogenesis


However, meat leaf out but covered with
gauze would still rot


Therefore, the idea that simpler organism
could arise from abiogenesis was still accepted

Proving that Microbes Are Present in
Dust Particles


Jablot’s vs. Needham’s Experiment


Jablots experiment supported the idea that
microbes are present in the air


Proving that Microbes Are Present in
Dust Particles


However, support for Jablot’s experiment
faltered when Needham’s results were
reported


Needham performed the same experiment
with mutton gravy


Microbial growth was in both containers


What do you think happened here?


These disputes would
be put to rest with
Louis Pasteur’s work

Proving that Microbes Are Present in
Dust Particles

Pasteurization


Pasteur also demonstrated that
spoilage bacteria could be killed
by heat that was not hot
enough to evaporate the
alcohol in wine. This application
of a high heat for a short time
is called pasteurization

Lister’s Work


English physician advanced the idea of
antisepsis in health care setting 1860’s


Dressed wounds with carbolic acid
(phenol)


Reduced deaths among patients by 2/3


Listerine Mouthwash

Koch’s Postulates


1876 Robert Koch provided proof that a
bacterium causes anthrax and provided
the experimental steps, postulates, used
to prove that a specific microbe causes a
specific disease


Koch was a physician and Pasteur’s young
rival

Koch’s Postulates

Mouse dies with sores

Take scraping and plate on agar

A heterogeneous population of bacteria

Grow
–

which one is the causative agent

Isolate all different strains and types and

inject into healthy mice and see which mice

develop similar phenotype and symptoms

Take a sample again from mice which died

of same symptoms and isolate the

causative agent again

Koch’s Postulates


A sequence of
experimental
steps to relate a
specific microbe
to a specific
disease

Koch’s Postulates

Used to prove the

specific causative

agent of an infectious

disease

Jenner’s Work


Observed that milkmaids did not acquire
smallpox


Milkmaids were exposed to chronic low
doses of cowpox and therefore acquired
specific immunity


1796 Jenner inoculated a person with
cowpox virus and found this person was
then protected against acquiring small pox


This protection is known as immunity


Called vaccinatin from vacca for cow

Alexander Fleming’s Work


In 1928 Fleming
discovered the first
antibiotic by accident


He observed that
Penicillium fungus
secreted a substance
which killed bacteria


Explain why a fungus
would do this


In 1940s penicillin was
tested clinically and
mass produced

Germ Theory of Disease


All of these aforementioned people and
others helped give rise to the germ theory
of disease


Germ Theory states that microorganisms
can invade other organisms and cause
disease


Before this many time politics and religion
would spur on erroneous theories

Part III

Introduction to Disease

Chronic vs. Infectious Disease


Chronic


Disease which persists over a long period of
time


Atherosclerosis, cancer & heart failure


Infectious


Organism enters and tissues & grows


Bacterial
–

Prokaryotic


Viral
–

Acellular


Protozoan
–

Eukaryotic


Causes symptoms in patients

Conquering Infectious Disease


The triumph over infectious disease?


Antibiotics discovered in 1940s


Vaccinations routinely delivered in the 1950s
through today


Eradication of polio and small pox


But then…


MRSA


Drug resistant TB


HIV


Ebola


Avia Flu


And more


Conquering Infectious Disease


What went wrong?


Medical advances


Older and sicker people live longer


More susceptible to garden variety microbes


Population is more mobile


Emerging diseases


Encroachment of humans into wild habitat


Rapid evolution and biochemical changes to
microbes


Microbes have a quick generation time

All Diseases

Old Standards

Syphilis

Measles

Staph Infections

Chicken Pox

Emerging

Avia Flu

Antigenic shift event

HIV in the 80’s

West Nile in US in 2001

Continental travel

Reemerging

Tuberculosis
-

TB

New drug

resistant strains

Immunocompromised

patients

Top Causes of Death

United States

Deaths

Worldwide

Deaths

1. Heart Disease

696,950

1. Heart Disease

8.12 x 10
6

2. Cancer

557,270

2. Stroke

5.51 x 10
6

3. Stroke

162,670

3. Res infection


3.88 x 10
6

4. Chronic LRD*

124,800

4. Cancer

3.33 x 10
6

5. Accidents

106,740

5. HIV/AIDS

2.78 x 10
6

6. Diabetes

73,250

6. Chronic LRD*

2.75 x 10
6

7. Flu & Pneumonia

65,680

7. Diarrheal disease

1.80 x 10
6

8. Alzheimer disease

58,870

8. Tuberculosis

1.57 x 10
6

9. Kidney problems

40,970

9. Malaria

1.27 x 10
6

10.Septicemia

33,865

10. Accidents

1.19 x 10
6

* Stands for lower respiratory disease

Infectious Diseases are shown in
red

Infectious

Disease

Statistics

Part IV

Taxonomy & Biological
Classification

Organizing Life


Classification


Orderly arrangement of organisms into groups
that indicate evolutionary relationships


Nomenclature


Assigning names to various taxonomic
rankings


Identification


Correct placement of organism into taxonomic
scheme

Taxonomy


Origins of organizing biological life


Carl von Linne or Linnaeus 1701
–

1778


System of recognizing and defining properties
of living organism followed by the placement
into specific slots


Grouped according to similar properties


Grouped according to evolutionary relatedness


Constantly being revised and refined


Taxonomy

Nomenclature


Scientists use a standard binomial system


Overseen by an international group


Verify that standard procedures were followed


Ascertain the uniqueness of each name


Make sure no other name exists


Nomenclature


Staphylococcus aureus


Staphule
–

bunch of grapes


Aureus
–

golden


Campylobacter jejuni


Kampylos
–

curved


Bakterion
–

little rod


Jejunum
–

section of small intestine


Giardia lamblia


Alfred Giard
–

French microbiologist


Vilem Lambl
–

Bohemian physician

Evolution & Phylogeny


Evolution


All new species originate from preexisting
species


Closely related organism have similar feature
due to evolution from common ancestral forms


Phylogeny


Tree of life


Classification based on evolutionary
relatedness

Whittaker’s

System

Whittaker’s System


Although used for many years this system
has problems in terms of evolutionary
relatedness


Kingdom Protista


Autotrophs & heterotrops are groups together


Archaea


Although these organisms are prokaryotic they
are more closely related to eukaryotic cells

Solution to Whittaker’s Tree


Biologist no longer group organisms into a
5 kingdom system


Currently a three domain system


Many original kingdoms still work


Plants, animals, fungi


However, Kingdom Protista & Kingdom Monera
have been extensively reorganized into many
different kingdoms

Three Domain System