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Unit E
Microbiology in Agriscience and Production Agriculture
Objective 11.00
What is a virus?
o A virus is an organism composed of a DNA or RNA core surrounded by
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NOT CLASSIFIED AS A TRUE LIVING ORGANISM
, only through
division in a
(viruses are parasitic)
Reproduce quickly, mutate often, and
o
o
o
o
Responsible for some of the most dangerous human ailments
Can be destroyed by
Human Immunodeficiency Virus
Often used as a
to transport genes into organisms
when genetically modifying organisms.
o Types of Viruses

(TMV)-often used as a
vector for genetic engineering in plants-1 long RNA molecule

-DNA packaged tightly in a protein
head-often used in genetic engineering
 Common viruses
 Human Immunodeficiency Virus(HIV)
 Influenza
 Common Cold
 Measles
 Norwalk
 Hepatitis
 Rabies
Prokaryotic Organisms
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What is a prokaryotic organism?
o A
o Usually have very short life spans
Characteristics of Prokaryotic Organisms
o Contain
o Can be
(produce their own energy)
or
(consume other things for energy)
o Also reproduce quickly and mutate often, but are not as tough as viruses
Examples of Prokaryotic Organisms
o Bacteria
o Cyanobacteria
o Blue-green algae
o Bacteria
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Characteristics of Bacteria
o Can be
to humans
o Unlike viruses, bacteria are not PARASITES, and do not need a host
o Molds and fungi including yeast are not bacteria
Beneficial Bacteria
o Provide a
to human activity through normal function
or manipulation through biotechnology techniques
o Examples:
 Nitrobactus alkalikus
 Lactobaccillius sp.
o Nitrobactus alkalikus
 Bacteria occurring
on the
roots of
, that change nitrogen in the air to a
form useful for plants
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o Lactobaccillus sp.
 A genus of microorganisms that have been introduced to foods (often
dairy products) to
Harmful Bacteria
o Affect agriscience products and processes in a negative manner, affecting both
plants and animals
o Example:
 Eescherichia coli (
)
 Clostridium botulinum
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 Pythium spp.
Destroying Harmful Bacteria
o
-kills
living organisms in a or on a
substance
o
-kills most harmful microorganisms, leaving some
beneficial organisms surviving
Multiform Bacteria
o Can either be beneficial or harmful to plants under different circumstances and
conditions
o Example:

-naturally
occurring bacteria that penetrates plant cells transmitting its own DNA to
the cells and causing the growth of a
(tumor like mass)
 Used in genetic engineering to transmit genes
Agriscience Uses of Bacteria
o Pharming
o Bioremediation
o Biocontrol
o Biofuels
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Example of Pharming
o Inclusion of
in milk
products to lower human cholesterol
Bioremediation
o Use of bacteria that consume
 Example- bacteria used to “
” oil from tanker spills, or excess
organic nutrients from animal waste
Biocontrol
o Use of beneficial bacteria in horticulture to kill harmful bacteria in soil, water and
on plant surfaces.
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o Very few applications in renewable energy or biofuels now, but lots of potential
applications
Eukaryotic Cells
 What is a Eukaryotic Cell?
o Advanced cells characterized by the presence of
and a distinct
.
o Usually occur in multicellular organisms, but also include a few single celled
Protists.
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Eukaryotic Cell Structures
o Cell membrane
o Golgi apparatus
o Mitochondria
o Nucleus
o Ribosomes
o Vacuoles
Cell Membrane
o
membrane
surrounding all eukaryotic cells.
o Protects the cell and controls the movement of substances into and out of the cell.
Golgi Apparatus
o Center for the
, and
other materials through the cell
o Like the post office
Mitochondria
o Structures inside the cell that convert simple sugars to a useful form of
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Nucleus
o A large central segment of the eukaryotic cell that contains the cell’s
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Ribosomes
o Small structures in the cytoplasm of the cell that utilize RNA to produce
for cell functions
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Vacuoles
o Specialized “
” in cells used for storage,
digestion, and excretion.
o Much larger in plant cells
Special Plant Cell Structures
o
-use
to capture
light energy for conversion to chemical energy
o
-structure outside the cell membrane that
helps support and protect cells.
 Not semi-permeable
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Specialized Eukaryotic Cells
o Diploid Cells
o Haploid Cells
o Stem Cells
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Diploid Cells
o Includes all
in multicellular eukaryotes (plants and
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animals)
o Examples: Skin cells, muscle cells, nerve cells
Cells
o Specialized reproductive cells in eukaryotes that contain ½ the amount of genetic
material of normal (diploid) cells
o Also called
o Haploid cells combine during sexual reproduction to create a fertilized egg
o 4 distinct types
 Male FemaleStem Cells
o Produced from the
o Special cells that differentiate into all diploid cells in the body.
Culturing Bacteria
 Ideal Bacterial Environments
o Most bacteria prefer warm moist environments, though specific species require
different culturing conditions
o Bacteria
 Deep sea ocean vents with no sunlight and little useable oxygen
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Bacteria Testing Methods
o
-method used to test surfaces for bacteria
 A sterile cotton swab is dipped in a dilution solution and rubbed across the
surface to be tested.
 The end of the swab is cut and dropped into the solution
 The infested solution is swirled at .1 ml extracted for plating
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o Plating
 The process of physically
bacteria on an
agar based culture media
 Plating Process
 To produce agar plates, heat a clear solution in a water bath. Next,
proceed to pour the solution into
and immediately seal.
 Bacteria can be spread using an
or glass “hockey stick”
 Plates should be sealed and incubated at
to avoid the growth of most bacteria harmful to humans (35-37
degrees for Salmonella)
Identifying/Counting Bacteria
o Different agar mixes can be used to culture specific types of bacteria.
o
is used to broadly identify certain
types of bacteria.
o Identifying individual strains is much more difficult.
Cleanup After Culture of Biological Labs
o Cultures should be placed in a biohazard bag for sterilization in an autoclave set at
o Agar should be disposed of according to lab protocol-not poured down sinks, as
liquid agar can quickly
o Individuals should always wear
and
immediately dispose of them after use.
 This is due to the hands being the most common point of contact.