review remember from earlier this year that there are two broad categories of organisms:...
Post on 28-Dec-2015
214 Views
Preview:
TRANSCRIPT
ReviewRemember from earlier this year that there
are two broad categories of organisms:
*Prokaryotes – have No membrane bound organelle
*Eukaryotes – have membrane bound organelle
Important Features-all are prokaryotes-all have plasmids (small circular
packages of DNA)-most have peptidoglycan in their
cell walls-flagella are made with a globular
protein called flagellin- no 9+2 arrangement
Cytosol Granules(Small chunks of food)
Locomotion (Methods of Movement)
Bacterial Flagellum- lacks microtubules
Pili- short, thin appendages
Bacteria
E. coli
E. coli
Nutrition Autotrophs- manufacture organic compounds
– Photoautotrophs- use light energy & CO2
– Chemoautotrophs-use inorganic substances like H2S, NH3, and other nitrogen compounds
Heterotrophs- obtain energy by consuming organic compounds
– parasites- get energy from living organisms
– saprobes (saprophytes)- get energy from dead, decaying matter; also called decomposers
Oxygen Preferences
obligate aerobes must have oxygen obligate anaerobes cannot live in
oxygen facultative anaerobes can grow
with or without oxygen
2 Bacteria Kingdoms
Kingdom Archaebacteria - are ancient bacteria that live in extreme environments
Kingdom Eubacteria - are generally referred to as bacteria or germs, and are considered more recent. Most types of bacteria belong in this kingdom.
First appeared approximately 3.7 BYA
The Archaebacteria:
do not have peptidoglycan in their cell walls
have ribosomes similar to eukaryotes
have unique lipids in their plasma (cell) membranes
The Archaebacteria also: have some genes that resemble
eukaryotic genes usually are not pathogenic (they
don’t usually make us sick!) live in extreme environments:
–high concentrations of salt
–extremes of pH and temperature
3 Archaebacterial Groups Methanogens Halophiles Thermoacidophiles = live in
extremely hot, acid environments
Methanogens
anaerobic bacteria that get energy by turning H2 and CO2 into methane (CH4)
live in mud, swamps, and the guts of cows, humans, termites and other animals
Halophiles are organisms that live in environments
with extremely high salt concentrations– some extreme halophiles can live in
solutions of 35 % salt. (seawater is only 3% salt!)
halophile means “salt loving” most halophiles are aerobic and
heterotrophic; others are anaerobic and photosynthetic, containing the pigment bacteriorhodopsin
Diversity of Halophilic Organisms
halophiles are found in salt lakes, salt marshes, subterranean salt deposits, dry soils, salted meats, hypersaline seas, and salt evaporation pools
the Red Sea was named after the halobacterium that turns the water red during massive blooms.
HalophileEnvironmentssolar salternsOwens Lake, Great Salt Lake,coastal splash zones,Dead Sea
Thermoacidophiles Like temperature and pH extremes
– Hot = up to 110ºC– Cold = down to 1ºC– Acid = as low as pH 2– Alkali = as high as pH 9
they are chemoautotrophs, using H2S the first Extremophile was found about 30
years ago
Extreme Temperatures Thermophiles - High temperature = 60-800C
– Thermal vents and hot springs
– May go hand in hand with chemical extremes Psychrophiles - Low temperature
– Arctic and Antarctic
»1/2 of Earth’s surface is oceans between 10C & 40C
»Deep sea –10C to 40C
»Most rely on photosynthesis
ThermophileEnvironments
Hydrothermal Vents in the ocean, and
Obsidian Pool in Yellowstone National Park
Psychrophile Environments
Alan Hills Ice Field: Antarctica
Thermophile Applications many industrial processes involve
temperature extremes, which is a problem for most enzymes– Enzymes to work on foods that need to be
refrigerated
– Perfumes - most don’t tolerate high temperatures
– Cold-wash detergents
– PCR reactions
Chemical Extremes Acidophiles - Acidic
– Again thermal vents and some hot springs Alkaliphiles - Alkaline
– Soda lakes in Africa and western U.S. Halophiles - Highly Salty
– Natural salt lakes and manmade pools
– Sometimes occurs with extreme alkalinity
Acidophiles Enzymes used to increase
efficiency of animal feeds– enzymes help animals
extract nutrients from feed»more efficient and less expensive
Life at High Temperatures, Thomas M. Brock
Acidophile Environments
Alkaliphiles
“Stonewashed” pants– Alkaliphilic enzymes soften fabric and
release some of the dyes, giving worn look and feel
Detergents– Enzymes to dissolve proteins or fats– Alkaliphilic enzymes can work with
detergents
Alkaliphile Environments
e.g. Mono Lake alkaline soda lake, pH 9, salinity 8%
Examples of Unusual Habitats
The bacterium pseudomonas was found living on a desert plant in the Negev Desert. The plant secretes salt through salt glands on its leaves.
Bacillus was found in the nasal cavities of desert iguanas. These iguanas have salt glands in their nasal cavities that secrete KCl brine during osmotic stress.
Special Techniques for SurvivalWhile external environments are “extreme”,
internal cell environments are “normal”.– Ways to protect the cell:
» Acidophiles and Alkaliphiles sometimes excrete protective substances and enzymes
» Acidophiles often lack cell wall» Some moderate halophiles have high
concentrations of a solute inside to avoid “pickling”
– Many microbes contain unusual enzymes
Interesting Facts
The term “red herring” comes from the foul smell of salted meats that were spoiled by halobacterium.
There have been considerable problems with halophiles colonizing leather during the salt curing process.
Future Applications
Many possible applications using halophiles are being explored such as:
– genetically engineering halophilic enzymes, encoding DNA into crops to allow for salt tolerance
– treatment of waste water
Summary Now you know something about
Extremophiles– where they live– how they survive
They are interesting because– they have enzymes that work in
unusual conditions
top related