Organizing Life's Diversity - Middletown High Biology

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Introduction to Microbiology

Ms. Crosby

Introduction


“microbiology’
-

the study of microorganisms


organisms to small to be seen with the naked eye


except in large groups


effects of large numbers often visible


e.g., chemical reactions in soil horizons


e.g., toxin and gas production in incompletely sterilised
food cans


e.g., disease in animals and plants


Diversity of Microbes


Bacteria
-
single celled prokaryotes


Protozoa
-
eukaryotic, single celled, colonial,
many ways of nutrition


Fungi
-

absorb nutrients, single celled
filamentous


Viruses
-
acellular entities


Others
-

worms, insects


Biologists use
scientific names
for species
because common
names vary in
their use.

Organizing Life’s Diversity

Ursus americanus

American black bear

The
History of Classification


When writing a scientific name, scientists use these
rules:

Organizing Life’s Diversity


The first letter of the genus name always is
capitalized, but the rest of the genus name and all
letters of the specific epithet are lowercase.


If a scientific name is written in a printed book or
magazine, it should be italicized.


When a scientific name is written by hand, both
parts of the name should be underlined.


After the scientific name has been written
completely, the genus name will be abbreviated to
the first letter in later appearances (e.g.,
C.
cardinalis
).

1.1 The History of Classification

Taxonomic Categories

Organizing Life’s Diversity


The taxonomic
categories used by
scientists are part of a
nested
-
hierarchal
system.


Each category is
contained within
another, and they

are arranged from broadest to most specific.

The
History of Classification

Species and Genus

Organizing Life’s Diversity


A named group of organisms is called a
taxa
.


A
genus

(plural, genera) is a group of species
that are closely related and share a common
ancestor.

The
History of Classification


A
family

is the next higher taxon,
consisting of similar, related genera.

Family

Organizing Life’s Diversity

The
History of Classification

Higher Taxa

Organizing Life’s Diversity


An
order

contains related families.


A
class

contains related orders.


A
phylum

or
division

contains related classes.


The taxon of related phyla or divisions is a
kingdom
.


The
domain

is the broadest of all the taxa and
contains one or more kingdoms.

The
History of Classification

Classification of Microbes

Taxonomic Hierarchy

Domain


Kingdom



Phylum




Class




Order




Family





Genus





Species

Dumb

Kings

Play

Chess

On

Funny

Green

Squares

Classification of Microbes

Taxonomic Hierarchy

Domain


Kingdom



Phylum




Class




Order




Family





Genus





Species

Binomal
Nomenclature uses
the Genus and
Species name to
identify each
creature.

Chapter 1 The Microbial World and You


Scientific Names


Staphylococcus aureus


Describes the clustered arrangement of the cells
(
staphylo
-
) and the golden color of the colonies

(
aur
-
).

Scientific Names


Escherichia coli


Honors the discoverer, Theodor Escherich, and
describes the bacterium’s habitat

the large intestine
or colon.

Scientific Names


After the first use, scientific names may be
abbreviated with the first letter of the genus
and the specific epithet:


Staphylococcus aureus

and
Escherichia coli

are
found in the human body.
S. aureus

is on skin and
E. coli

in the large intestine.

Grouping Species


The broadest category in the classification used
by most biologists is the domain.

Domains
and Kingdoms

Organizing Life’s Diversity


The most widely used biological classification
system has six kingdoms and three domains.


The three domains are Bacteria, Archaea, and
Eukarya.


The six kingdoms are Bacteria, Archaea,
Protists, Fungi, Plantae, and Animalia.

Domain Bacteria


Eubacteria

are
prokaryotes whose cell
walls contain
peptidoglycan.

Organizing Life’s Diversity


Eubacteria are a diverse
group that can survive in
many different environments.

Domains
and Kingdoms


Prokaryotes


Peptidoglycan cell
walls


Binary fission


For energy, use
organic chemicals,
inorganic chemicals,
or photosynthesis

Bacteria

Figure 1.1a

Domain Archaea


Archaea

are thought to be more ancient than
bacteria and yet more closely related to our
eukaryote ancestors.

Organizing Life’s Diversity


Archaea are diverse in shape and nutrition
requirements.


They are called extremophiles because
they can live in extreme environments.

Domains
and Kingdoms


Prokaryotic


Lack peptidoglycan


Live in extreme
environments


Include:


Methanogens


Extreme halophiles


Extreme thermophiles

Archaea
:

Halobacteria not
from book
Domain Eukarya


All eukaryotes are classified in Domain
Eukarya.

Organizing Life’s Diversity


Domain Eukarya contains Kingdom
Protista, Kingdom Fungi, Kingdom
Plantae, and Kingdom Animalia.

Domains
and Kingdoms

Kingdom Protista

Organizing Life’s Diversity


Protists are
classified into three
different groups

plantlike, animal
-
like, and
funguslike.


Protists

are eukaryotic organisms that can
be

unicellular, colonial,

or multicellular.

Domains
and Kingdoms


Eukaryotes


Absorb or ingest
organic chemicals


May be motile via
pseudopods, cilia, or
flagella


Most free some
parasites

Protozoa

Figure 1.1c

Kingdom Fungi

Organizing Life’s Diversity


A
fungus

is a unicellular or multicellular

eukaryote that
absorbs

nutrients from organic

materials in its

environment.


Member of Kingdom
Fungi are

heterotrophic, lack motility, and have cell
walls.

Domains
and Kingdoms

Kingdom Plantae


Members of Kingdom Plantae form the base
of all terrestrial habitats.

Organizing Life’s Diversity


All plants are
multicellular and have
cell walls composed of
cellulose.


Most plants are

autotrophs, but some are heterotrophic.

Domains
and Kingdoms

Kingdom Animalia


All animals are heterotrophic, multicellular
eukaryotes.

Organizing Life’s Diversity


Animal organs often are
organized into complex
organ systems.


They live in the water,
on land, and in the air.

Domains
and Kingdoms

Organizing Life’s Diversity

Domains
and Kingdoms

Viruses

An Exception


A virus is a nucleic acid surrounded by a
protein coat.

Organizing Life’s Diversity


Viruses do not possess cells, nor are they
cells, and are not considered to be living.


Because they are nonliving, they usually
are not placed in the biological
classification system.

Domains
and Kingdoms


Acellular


Consist of DNA
or
RNA
core


Core is surrounded by
a protein coat


Coat may be enclosed
in a lipid envelope


Viruses are replicated
only when they are in
a living host cell

Viruses

Figure 1.1e


Eukaryote


Multicellular
animals


Parasitic
flatworms and
round worms are
called
helminths
.


Microscopic
stages in life
cycles.

Multicellular Animal Parasites

Figure fluke

Multicellular Parasites


Worms, insects

Modern Developments in
Microbiology


Bacteriology is the study of bacteria.


Mycology is the study of fungi.


Parasitology is the study of protozoa and
parasitic worms.


Recent advances in genomics, the study of an
organism’s genes, have provided new tools for
classifying microorganisms.

Modern Developments in
Microbiology


Immunology is the study of
immunity. Vaccines and
interferons

are being
investigated to prevent and
cure viral diseases.


The use of immunology to
identify some bacteria
according to serotypes
(variants within a species) was
proposed by Rebecca
Lancefield in 1933.

Figure 1.4 (3 of 3)

Modern Developments in
Microbiology


Virology is the study of viruses.


Recombinant DNA is DNA made from two
different sources. In the 1960s, Paul Berg
inserted animal DNA into bacterial DNA and the
bacteria produced an animal protein.


Recombinant DNA technology, or genetic
engineering, involves microbial genetics and
molecular biology.


Microbial ecology


Bacteria recycle carbon, nutrients, sulfur, and
phosphorus that can be used by plants and animals.

Microbes and Human Welfare

Bioremediation


Bacteria degrade organic
matter in sewage.


Bacteria degrade or
detoxify pollutants such
as oil and mercury.

UN 2.1

Biological Insecticides


Microbes that are pathogenic to insects are
alternatives to chemical pesticides in preventing
insect damage to agricultural crops and disease
transmission.


Bacillus thuringiensis

infections are fatal in many
insects but harmless to other animals, including
humans, and to plants.

Modern Biotechnology and Genetic
Engineering


Biotechnology, the use of microbes to produce
foods and chemicals, is centuries old.


Genetic engineering is a new technique for
biotechnology. Through genetic engineering,
bacteria and fungi can produce a variety of
proteins including vaccines and enzymes.

Modern Biotechnology and Genetic
Engineering (continued)


Missing or defective genes in human cells can be
replaced in gene therapy.


Genetically modified bacteria are used to protect
crops from insects and from freezing.

Microbes and Human Disease


Bacteria were once classified as plants giving
rise to use of the term
flora

for microbes.


This term has been replaced by
microbiota
.


Microbes normally present in and on the
human body are called normal microbiota.

Normal Microbiota


Normal microbiota prevent growth of pathogens.


Normal microbiota produce growth factors such as
folic acid and vitamin K.


Resistance is the ability of the body to ward off
disease.


Resistance factors include skin, stomach acid, and
antimicrobial chemicals.


Biofilms are extremely important in microbial
ecology

Infectious Diseases


When a pathogen overcomes the host’s
resistance, disease results.


Emerging infectious diseases (EID): New diseases
and diseases increasing in incidence.

Emerging Infectious Diseases


West Nile encephalitis


West Nile virus


First diagnosed in the West Nile region of Uganda
in 1937


Appeared in New York City in 1999

Emerging Infectious Diseases


Avian Influenza A H5N1


Severe acute respiratory syndrome
(SARS)


West Nile encephalitis (WNE)


Bovine spongiform encephalitis (BSE)


Creutzfeld
-
Jacob disease (CJD)


0157:H7 E. coli


Flesh eating bacteria


Ebola


Marburg


Cryptosporidiosis


AIDS


HIV virus




Emerging Infectious Diseases


Bovine spongiform encephalopathy


Prion


Also causes Creutzfeldt
-
Jakob disease (CJD)


New variant CJD in humans is related to cattle fed
sheep offal for protein

Emerging Infectious Diseases


Escherichia coli

O57:H7


Toxin
-
producing strain of
E. coli


First seen in 1982


Leading cause of diarrhea worldwide

Emerging Infectious Diseases


Invasive group A
Streptococcus


Rapidly growing bacteria that cause extensive

tissue damage


Increased incidence since 1995

Emerging Infectious Diseases


Ebola hemorrhagic fever


Ebola virus


Causes fever, hemorrhaging, and blood clotting


First identified near Ebola River, Congo


Outbreaks every few years

Emerging Infectious Diseases


Avian influenza A


Influenza A virus (H5N2)


Primarily in waterfowl and poultry


Sustained human
-
to
-
human transmission has not
occurred yet


Swine Flu


(H1N1)


expected to be a pandemic

for the next 3 years. May infect >1billion people


Emerging Infectious Diseases


Severe acute respiratory syndrome (SARS)


SARS
-
associated
Coronavirus


Occurred in 2002
-
2003


Person
-
to
-
person transmission

Emerging Infectious Diseases


Acquired immunodeficiency syndrome (AIDS)


Human immunodeficiency virus (HIV)


First identified in 1981


Worldwide epidemic infecting 44 million people;
14,000 new infections every day


Sexually transmitted disease affecting males and
females


In the United States, HIV/AIDS cases: 30% are female
and 75% are African American

Emerging Infectious Diseases


Cryptosporidiosis


Cryptosporidium

protozoa


First reported in 1976


Causes 30% of diarrheal illness in developing
countries


In the United States, transmitted via water

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TULAREMIA


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OTHER AGENTS

Major Fields in Microbiology


medical microbiology


diseases of humans
and animals


public health microbiology


control and
spread of communicable diseases


immunology


how the immune system
protects a host from pathogens

56

More Fields…


microbial ecology is concerned with the
relationship of organisms with their
environment


less than 1% of earth’s microbial population
has been cultured


agricultural microbiology is concerned with
the impact of microorganisms on
agriculture


food safety microbiology


animal and plant pathogens

More Fields….


industrial microbiology began in the 1800s


fermentation


antibiotic production


production of cheese, bread, etc.


microbial physiology studies metabolic
pathways of microorganisms

More Fields….


molecular biology, microbial genetics, and
bioinformatics study the nature of genetic
information and how it regulates the
development and function of cells and
organisms


microbes are a model system of genomics