the ultimate outcome of metabolic activity is reproduction growth refers to an increase in...
TRANSCRIPT
CH 19- BACTERIA
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
1. Cytoplasmic membranes don’t contain fatty acids so they don’t melt
2. DNA is unique heat-stable supercoils
3. Enzymes are heat stable
2 regions of body that acidity reduces microbes and what happens if malfunctions
1. Stomach
Heliobacter pylori- neutralizes 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 for- maintain 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=lpI4WCM_9pM
Microbes and Oil Spills
http://www.youtube.com/watch?v=xhLu-5w_66A
Quorum Sensing
Article Reading
Shapes
Reproduction Binary Fission
1. Cell replicates DNA
2. Cell grows, DNA moves apart
3. Forms a cross wall
4. 2 new daughter cells
SporesReproductive cells that can make a clone of
original organism
BuddingOutgrowth of original cell receives genetic
material and enlarges
Endospore formation
1. Replicates DNA
2. Cytoplasm splits
3. Membrane grows to make spore coat
4. Endospore is released
Exponential GrowthOccurs 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 capacity- largest 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 Sterilization- flash 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=LKJrNHRcMAE
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 tissueCauses painful swelling & kills tissue
Clostridium tetani
Tetanus- infection of the nervous systemMuscle 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 Fevercauses 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/black-death/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 nodesSpread from cat bites or scratches