the ultimate outcome of metabolic activity is reproduction growth refers to an increase in...

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