Transcript Microbiology: A Systems Approach, 2nd ed.

Introduction to microbiology.
Classification and nomenclature of
microorganisms.
09.02.2011
Course Introduction
Instructor:
Dr Elena Romancenco
Department of Microbiology,
Virology and Immunology
E-mail:
[email protected]
WEBSITE:
www.microbio.ukoz.com
Course objectives
 List
major groups of microorganisms and
their habitats.
 Overview
 Describe
and history of Microbiology.
the system of scientific
nomenclature used to name
microorganisms.
Definition

Microbiology (mikros bios logos –
small, live, study) study
microorganisms and their activities.

Microbiology is the study of
microorganisms usually less than
1mm in diameter which requires
some form of magnification to be
seen clearly.

Microbiology - study the organisms
that can exist as single cells, contain
a nucleic acid genome for at least
some part of their life cycle, and are
capable of replicating that genome
themselves or getting replicated with
the help of host cells
Branches of
Microbiology
 Bacteriology:
study of bacteria
 Mycology: study of fungi
 Virology: study of viruses

Beijerinck, NE: discovered intracellular
reproduction of TMV; coined the term
“virus” (1899)
 Parasitology:
study of protozoa and
parasitic worms
Branches of
Microbiology

Immunology: study of immunity




Edward Jenner, UK: developed vaccination (1798)
Metchnikoff, RU: discovered phagocytes (1884)
Paul Ehrlich, DE: theory of immunity (1890)
Chemotherapy




Treatment of disease by using chemical means
Antibiotics produced naturally
Synthetic drugs
Paul Ehrlich (1878) – used arsenic compounds
to fight disease
Branches of
Microbiology

Chemotherapy



Alexander Fleming, Scotland (1928) discovered
penicillin
Selman Waksman, Ukraine (1944) discovered
streptomycin
Problems


Toxicity of drugs => Selective toxicity
Resistance of bacteria to drugs
Microorganisms are
everywhere, but why is so
important to learn about
them?
Affect our lives in many
different ways.
 Microbes
are capable of growing in a wide
variety of environments.

Bacteria will grow in frigid glaciers to
boiling volcanic springs, dry sands to the
open ocean.
IMPORTANCE OF
MICROORGANISMS

Microorganisms are the oldest forms of life.
 Nutrient production & energy flow
 Production of foods
 Decomposition (bioremediation)
 Without certain microorganism life could not exist;
produce O2 and N2
 Production of drugs & vaccines
 Genetic engineering
 Causing disease
Microorganisms have killed more people than have ever
been killed in war.
Why Study Medical
Microbiology?

The majority of serious diseases in humans (especially those of
early childhood) are due to microbial infections.

Prior to the discovery of antibiotics and vaccines, a large
proportion of children died before adulthood because of
infectious disease.

Till 1900, the average life expectancy in the United States was 40
years of age.

In 2000 - 80 years, largely due to the near eradication of most
serious early childhood diseases.

This trend is seen in the gap between developed and developing
countries in terms of causes of death (mortality).
MICROBES
 MICROBES
includes all those living
organisms that can not be viewed (seen)
in any detail by the human eye.
 Alternatively,
a MICROBE is any living
creature that must be examined with a
magnifying lens in order to see its unique
physical characteristics (size, shape,
motility, color).
Microbes
Pathogen or pathogenic - capable of producing
disease.

Though only a minority of microorganisms are pathogenic,
practical knowledge of microbes is necessary for their treatment
so is highly relevant to medicine and related health sciences.


Normal flora [normal microbiota] - not typicallydisease-causing

•
•
•
•
•
•
•
microorganisms normally found in and on healthy individuals.
on the skin,
in the eyes,
in the nose,
in the mouth,
in the upper throat,
in the lower urethra,
in the lower intestine.
the Bacterium
Escherichia coli;
a photosynthetic
cyanobacterium
a fungus
Ebola virus
the malaria
parasite (a
protozoan
A,
Influenza virus;
C,
Staphylococcus aureus;
B,
West Nile
Virus;
D, Streptococcus
pneumoniae.
Microbiologists may be interested in
various characteristics or activities of
microbs and may study:






Microbial morphology
Microbial cytology
Microbial physiology
Microbial ecology
Microbial genetics and molecular biology
Microbial taxonomy
Classification of life
 For
many years, living organisms were
divided into two kingdoms:

Animalia (animal) and

Plantae (vegetable).
Classification Schemes
Two kingdoms
Plantae
Plantae
Animalia

But after 1800s, scientists realized that these
two kingdoms could not adequately express the
diversity of life.

Since the 1960s, the most widely used scheme five kingdoms.

Viruses are separate group of biological entities,
although not organisms in the same sense as
Eukaryotes, Archaea and Bacteria.
Classification schemes,
5 kingdoms
Plantae
Monera
Protista
Plantae
Fungi
Prokaryotes
Domain
Bacteria
Domain
Archaea
(Eubacteria) (Archaeabacteria)
Eukaryotes
Animalia
Classification of Life

3 major Domains of
life




Bacteria
Archaea
Eukaryota (Eukarya)
The first two are Prokaryotes
(Bacteria and Archaea)without true nucleus, while
the Eukaryotes all have a true
nucleus in each cell.
The 3 Domains. Source:
http://www.ucmp.berkeley.edu/alllife/images/domains_small.gif
Kingdom Monera

All organisms in the Kingdom Monera are prokaryotes.


lack nuclei and organelles
most of their cell walls are made of peptidoglycan (the exceptions
are the archaebacteria).

The archaebacteria have cell walls that lack peptidoglycan, cell
membranes that utilize different lipids, and ribosomes similar to
those found in eukaryotes.

The bacteria (eubacteria-true bacteria) are characterized by how
they metabolize resources, their means of motility, and their
shape.

Most organisms in the Kingdom Monera reproduce through
binary fission (asexual) or conjugation (sexual).
Bacteria

Most utilize flagella for movement.

Digestion is extracellular (outside the cell) and
nutrients are absorbed into the cell.

Circulation and digestion in Kingdom Monera is
accomplished through diffusion.
Bacterial Classification
by
 Metabolism

Morphology (shape)
 Staining, etc
According the
metabolism



Autotrophs manufacture their own organic
compounds.
Heterotrophs obtain their energy by feeding
on other organic substances.
Saprophytes, a special kind of heterotroph,
obtain energy by feeding on decaying matter.
According the symbiotic
relationships with other organisms:



In parasitism, harm is caused to the host.
In commensalism, one organism benefits
while the other is unaffected.
In mutualism, both organisms benefit.
According the respiration:



In obligate aerobes, the prokaryotes must
have oxygen to live.
In obligate anaerobes, the organisms cannot
survive in the presence of oxygen.
And in facultative anaerobes they can
survive with or without oxygen.
According the shapes:

cocci (spherical),

bacillus (rod shaped), and

spirillum (spirals).
Classification of bacteria
• Cocci




Micrococcus
Staphylococci
• Irregular clusters of cocci
Diplococci
• Pairs of cocci
Streptococci
• Chains of cocci
Classification of bacteria

Bacilli




Rod like
Diplobacilli
• Pairs of bacilli
Streptobacilli
• Chains of bacilli
Spirochetes
• Spiral
Size of bacteria

Unit of microbial
measurement

micrometers (um)
• 1 um being 10-6 m or
0.000001 m(1/25,000
inch)

nanometers
• 1 nm being 10-9 or
0.000000001 m.

Pathogenic bacterial
species vary from
approximately 0.4 to 2
um in size
Taxonomy

Taxonomy is the classification of organisms. The
most common system in use today is the Five
Kingdoms:






Organisms in each kingdom are divided into phyla.






Monera (Prokaryota),
Protista,
Fungi,
Plantae, and
Animalia.
In each phylum, organisms are separated into classes.
In each class, organisms are segregated into orders.
In each order, organisms are divided into families.
In each family, organisms are separated by genus.
And finally, in each genus organisms are divided into species.
Just remember that King Philip Can Order For Genial Students.
Naming micoorganisms

Binomial (scientific) nomenclature

Gives each microbe 2 names



Genus - noun, always capitalized and may be
abbreviated
species - adjective, lowercase, never abbreviated
A genus name may be used alone to indicate a genus
group; a species name is never used alone
• eg: Bacillus subtilis
B. subtilis

Both italicized or underlined



Staphylococcus aureus (S. aureus)
Bacillus subtilis (B. subtilis)
Escherichia coli (E. coli)
Nomenclature
 Common
or descriptive names
(trivial names)

Names for organisms that may be in
common usage, but are not taxonomic
names
• eg: tubercle bacillus
(Mycobacterium tuberculosis)
• meningococcus
(Neiserria meningitidis)
• Group A streptococcus
(Streptococcus pyogenes)
Eukaryotes
Prokaryotes








Kingdom - Monera
Domain - Bacteria
Phylum – Proteobacteria
Class – Gammaproteoba
Order – Enterobacteriale
Family – Enterobacteriace
Genus – Escherichia
Species – Escherichia coli
"The role of the
infinitely small in
nature is infinitely
large"
Louis Pasteur
Historical Perspectives
Historical
YEAR
NAME
ACHIEVEMENT
1st century BC
Varo
Concept of “Animalia
minuta”
1546
Fracostorius
Contagion- Cause of
syphilis
1590
Jensen
Hand lens
1683
Antony van
Leeuwenhoek
First Microscope
“Animalcules”
1678
Robert Hook
Compound microscope
1745
Needham (Priest)
Abiogenesis
1836
Schulze & Schwan
Air contains microbes
1840
Oliver Homes, Poet
physician
Contageousness &
Puerperal fever
1846
Ignaz Semmelweis
Cause, concept &
prophylaxis of child-bed
fever
1853
Augustino Bassi
Silk worm disease due to
a fungus
Pioneers of
Microbiology

Robert Hooke, UK (1665)




Spontaneous generation


Proposed the Cell Theory
Observed cork with crude microscope
All living things are composed of cells
Some forms of life could arise spontaneously from
non-living matter
Francesco Redi, IT (1668)

Redi’s experiments first to dispprove S.G.
Antonie van Leeuwenhoek

First to observe living
microbes
 his single-lens
magnified up to 300X
(1632-1723)
Louis Pasteur








(1822-1895)
French chemist
Father/Founder of Modern
Microbiology
Fermentation – a
microbiological process
Beer/Wine not produced
without microbes
Showed microbes caused
fermentation & spoilage
Disproved spontaneous
generation of m.o.
Developed aseptic techniques.
Developed a rabies vaccine.
Louis Pasteur 1822-95







Methods & Techniques of cultivation
Introduced sterilization
Tyndalization (Tyndal-1877)
Studied Silkworm disease, anthrax,
chicken cholera, hydrophobia.
Introduced live vaccines – Jenner (Cowpox vaccine)
Antirabic vaccine
Pasteur Institutes
Joseph Lister 1867

Prof of Surgery,
Glasgow Royal
Infirmatory
 Introduced Antiseptic
Surgery
 Called Father of
Antiseptic Surgery
Robert Koch







(1843-1910)
German general practitioner
Perfected bacteriological
techniques
Isolated pure cultures of
bacteria for the first time
Discovered Anthrax bacilli,
Cholera vibrio, M. tuberculosis
Father of Medical Microbiology
Hypersensitivity
Established a sequence of
experimental steps to show
that a specific m.o. causes a
particular disease.
Koch’s postulates
The organism must be present in every case of the
infectious disease.
It should be possible to isolate the organism in
pure culture from the lesion.
Inoculation of the pure culture into suitable lab
animal should produce a similar disease.
It should be possible to re-isolate the organism in
pure form from the lesions produced in the
experimental animal.
Specific antibodies to the organism should be
demonstrable in patients suffering from the
disease.
Highlights in the History of
Microbiology
1887
 Invented Petri Dish
(R.J. Petri)
1892
 Discovered viruses (Dmitri
Iosifovich Ivanovski)
1899
 Recognized viral
dependence on cells for
reproduction (Martinus
Beijerinck)
1900
 Proved mosquitoes carried
the yellow fever agent
(Walter Reed)
1910
 Discovered cure for syphilis
(Paul Ehrlich)
1928
 Discovered Penicillin
(Alexander Fleming)
Highlights in the History of
Microbiology
1977
Developed a method to
sequence DNA (W.
Gilbert & F. Sanger)
 1983
Polymerase Chain
Reaction invented (Kary
Mullis)
 1995
First microbial genomic
sequence published (H.
influenzae) (TIGR)
