Transcript Microbiology - North Mac Schools


The ultimate outcome of metabolic
activity is reproduction

Growth refers to an increase in
population which is a discrete colony
Nutrients are chemicals

And are used for energy

How do bacteria get energy?

Autotrophs-make their own food

Heterotrophs-get food from other organisms

Chemotrophs-food from chemicals

Phototrophs-food from light

The most common chemical element in cells
(never a limiting nutrient) is Hydrogen
Bacterial Environments

Organotrophs-get e- from organic molecules

Lithotrophs-get e- from inorganic molecules

Obligate Aerobes-have to have oxygen

Obligate Anaerobes-oxygen is deadly

Facultative anaerobes-aerobes that can use
anaerobic pathways ex: fermentation
Bacterial Environments

Aerotolerant anaerobes- don’t normally use oxygen
but can
Ex: lactobacilli (cucumbers>pickles)
(milk>cheese)

Microaerophiles-use small amounts of Oxygen
Ex: heliobacter pylori- stomach ulcers

Peroxide- toxic form of oxygen
Nitrogen

What element is often a growth-limiting
nutrient- Nitrogen , needed to make
proteins

Few organisms can utilize nitrogen gas.

These six make up more than 95% of
the dry weight of cells C,H,O,N,P, and S
Definitions

Trace elements- required in small amounts

Growth factors- vitamins

Minimum growth temperature- lowest tem needed to
survive

Maximum growth temperature-highest temp capable
of surviving at

Optimum growth temperature-desired temp
Loving Environments

Psychrophiles- super cold
Ex: ice, freezer, refrigerators, cold water, cause food spoilage

Mesophiles-best at 20-40 C (human body 37C)
Ex: human pathogens

Thermophiles- hot
Ex: hot springs, don’t cause disease

Hyperthermophiles-Archae, extremely hot
Ex: hydrothermal vents, volcanic necks

Neutrophiles- pH 6.5-7.5, human body

Acidophiles- acidic habitats
3 features of hyperthermophiles
that enable them to remain intact
Cytoplasmic membranes don’t contain
fatty acids so they don’t melt
2. DNA is unique heat-stable supercoils
3. Enzymes are heat stable
1.
2 regions of body that acidity
reduces microbes and what happens
if malfunctions
1. Stomach
Heliobacter pylorineutralizes stomach acid
and causes ulcers
2. Vagina
-disruption causes
yeast infection
ex:antibiotics
How can microbes survive in dry
conditions
1.
Cell wall retain water for months
2.
Spores & cysts can cease metabolic
activity for years

Hypertonic- greater amount of
solutes

Hypotonic- lower amount of
solutes

Plasmolysis- shriveling of
cytoplasm

Obligate halophiles-high
osmotic pressure- Great Salt
Lake, Dead Sea

Barophiles- extreme pressure
and what do they need this formaintain 3D shape
Relationships

Antagonistic relationships- one organism
harms or kills another

Synergistic relationships- each receive
benefits

Symbiotic relationships- interdependent
on each other rarely live outside the
relationship
Biofilms
bacteria can join together on essentially
any surface and start to form a
protective matrix around their group
 http://www.youtube.com/watch?v=lpI4W
CM_9pM

Microbes and Oil Spills

http://www.youtube.com/watch?v=xhLu5w_66A
Quorum Sensing

Article Reading
Shapes
Reproduction

1.
2.
3.
4.
Binary Fission
Cell replicates DNA
Cell grows, DNA moves
apart
Forms a cross wall
2 new daughter cells

Spores
 Reproductive cells that can make a clone of
original organism

Budding
 Outgrowth of original cell receives genetic
material and enlarges
Endospore formation
Replicates DNA
2. Cytoplasm splits
3. Membrane grows to make spore coat
4. Endospore is released
1.
Exponential Growth
Occurs under ideal conditions... Unlimited resources or no predation
Bacteria reproduce on average every 20 minutes.
Starting with 1...
20 minutes – 2 bacteria
40 minutes – 4 bacteria
1 hour – 8 bacteria
2 hours – 64 bacteria
4 hours – 512 bacteria
1 day – 4,720,000,000,000,000,000,000 bacteria!
If this population growth went unchecked,
bacteria would cover the planet!
Carrying capacitylargest number of individuals
that a given environment can support
Phases of Growth

1. Lag Phase- adjusting to new
environment, synthesize enzymes to use
nutrients

2. Log Phase- rapid chromosome
replication, growth, reproduction
-population increases logarithmically

3. Stationary Phase- nutrients depleted,
wastes increase,rate decreases
# dying = #produced

4. Death Phase- nutrients not added,
wastes not removed
# dying › # produced
Archae- lack peptidoglycan in cell
walls

Extremophiles- extreme conditions

Thermophiles- extreme hot

Halophiles- salty environments

Methanogens- obligate anaerobes,
make methane gas, hydrothermal vents
Physical Methods for Control

1. Heat is used for sterilization, canned goods

Thermal Death Point- lowest temp that kills all
cells in a broth in 10mins

Thermal Death Time-time it takes to completely
sterilize a volume of liquid at a set temp

Decimal Reduction Time-time required to
destroy 90% of microbes in a sample

Clostridium botulinum causes botulism toxin
inside sealed cans
2. Moist Heat- denatures proteins
& destroys cytoplasmic
membranes

1) Boiling-water boils at lower temps at higher elevations
because of atmospheric pressure is lower, so you have to
boil longer

Does boiling actually sterilize? No, sanitizes not
sterilize, endospores can survive

2) Autoclaving- add pressure
pressure chamber used for food packing
How do you know when something has been sterilized (2
ways)?
1.
Chemical tab that changes color
2.
Melt plastic beads

3)Pasteurization- heating enough to
destroy the microorganisms that cause
spoilage without raising the temps to ruin
taste
 Flash Pasteurization –high temp, short
time (milk)
4) Ultrahigh-Temperature Sterilizationflash heating to rid of ALL microbes,
extremely hot for 1 second (dairy creamer)
3. Dry Heat- high temps for
longer period of time
1)Refrigeration- halts growth on food
2) Dessiccation- drying (fruits, beans, nuts)
Lyphilization-freeze drying, liquid Nitrogen
3) Filtration-passage of a fluid through a
sieve to trap particles
ex: antibiotics, vaccines, enzymes
4) Osmotic Pressure- high concentrations
of salt/sugar in foods
ex: jams, jellies, honey, jerky
5) Radiation- high speed subatomic
particles through cells
6) Ionizing Radiation-gamma, x-rays, don’t
work on thick objects
7) Nonionizing Radiation-penetrate further,
meats, spices, fresh fruits & veges, kills
insects
8. Sterilization- removal/destruction of all
microbes
9. Aseptic- environment free of
contamination of pathogens
10. Disinfection- physical or chemical
agents to destroy pathogens
ex: bleach, alcohol, UV light, heat
11. Antiseptic- chemical used on skin or
tissue
12. Degerming- removal of microbes from a
surface by scrubbing
ex: washing hands
13. Sanitization- disinfecting places and utensils
used by the public
ex: steam, high pressure water
14. Pasteurization- heat to kill, reduce spoilage
Microbial Death- permenant loss of reproductive
ability
Frontline- antibiotic resistance

http://www.pbs.org/wgbh/pages/frontline/
hunting-the-nightmare-bacteria/
Understanding Bacteria

http://www.youtube.com/watch?v=LKJrN
HRcMAE

5 segments
Pathogens- bacteria that cause
disease

Staphylococcus Aureus
 Found on skin & in respiratory
tract
 Causes pneumonia
Staphylococcus epidermidis
Normal body flora
 Biofilms- intravascular devices
(prosthetic heart valves, shunts, etc.) but
also commonly occur in prosthetic joints,
catheters, and large wounds, UTI’s

Streptococcus pyogenes

Scarlet Fever- fever, sore throat, rash
Streptococcus agalactiae

Urogenital tract infections
Streptococcus pneumoniae

pneumonia
Bacillus anthracis
Anthrax- common cold to severe
breathing problems to death
 2001 attack on government- inhalational
endospores

Clostridium botulinum
Food poisoning from canned foods
 Dented cans

Clostridium perfringes

Gas gangrene- bacterial produces gas
in tissue
 Causes painful swelling & kills tissue
Clostridium tetani

Tetanus- infection of the nervous system
 Muscle spasms
Mycobacterium tuberculosis
Aka: TB
 Respiratory system-cough up mucus or
blood

Mycobacterium leprae

Leprosy- skin sores, nerve damage
Neisseria gonorrhoeae
STD- gonorrhea (also called "The Clap”)
 discharge from the genitals which may
be foul smelling

Salmonella typhi

Typhoid Fever
 causes diarrhea and a rash
 Spread fecal-oral
Proteus mirabilis
Kidney Stones
 Live off of urea so inhabit urinary tract

Yersinia pestis
Black Plague/Black Death/Bubonic Plague
 During the 6th century AD, the plague ravaged
the known world over a 50 year period causing
100 million deaths. The "black death" again
devastated Europe during the 14th century over a
5 year period causing 25 million deaths (25% of
the European population).
 Spread through rodents & fleas
 http://www.history.com/topics/blackdeath/videos#coroners-report-plague

Bordetella pertusis

Whooping Cough
Rickettsia rickettsii
Rocky mountain spotted fever
 Carried by ticks

Helicobacter pylori

Stomach ulcers
Vibrio cholerae
Cholera- severe diarrhea
 Spread in unsanitary drinking water

Borrelia burgdorferi

Lyme Disease- spread through ticks
 Starts like flu, bulls-eye rash, may lead to
muscle pain or paralysis
Bartonella henselae

Cat scratch fever- fever & headache,
enlarged lymph nodes
 Spread from cat bites or scratches