Archaebacteria and Eubacteria

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

Cytosol Granules(Small chunks of food)

Locomotion (Methods of Movement)

Bacterial Flagellum Pili- short, thin appendages

Bacteria

E. coli

E. coli

Nutrition-DO NOT NEED TO COPY

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.

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-turn H2 and CO2 into

methane Halophiles-salt Thermoacidophiles = live in

extremely hot, acid environments

Methanogens

anaerobic bacteria that get energy by turning H2 and CO2 into methane

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

Diversity of Halophilic Organisms

halophiles are found in salt lakes, salt marshes, subterranean salt deposits, dry soils, salted meats

the Red Sea was named after the halobacterium that turns the water red during massive blooms.

HalophileEnvironmentsOwens Lake, Great Salt Lake,coastal splash zones,Dead Sea

Thermoacidophiles Like temperature and pH extremes

– Hot = up to 3740ºF– Cold = down to 34ºF– Acid = pH 2– Basic = pH 9

they are chemoautotrophs 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

»Most rely on photosynthesis

ThermophileEnvironments

Hydrothermal Vents in the ocean, and

Obsidian Pool in Yellowstone National Park

Psychrophile Environments

Alan Hills Ice Field: Antarctica

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

Acidophile Environments

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.

IDENTIFICATION of BACTERIA – 3 MAIN SHAPES

Baccili

Cocci

Spirillum

Identification – cell walls There is a method used to tell apart two types

of cell walls in eubacteria, called Gram staining.

Gram-positive bacteria stain violet– These bacteria have 1 cell membrane surrounded

by a thick peptidoglycan wall which holds the color well.

Gram-negative bacteria stain pink– These bacteria have a thin peptidoglycan wall

between 2 membranes. The wall is too thin to hold the color as well.

Bacterial diseases

Preventing bacterial disease

Vaccines- injection of a weakened form of a pathogen that prepares the body to produce immunity to the pathogen

Antibiotics- given after infection, they block the growth and reproduction of bacteria

Controlling bacteria

How can we control the presence of bacteria?

– Sterilization with heat– Disinfectants– How we store food– How we process food

They aren’t all bad!

We need bacteria for:– Decomposition- help recycle materials in

nature– Nitrogen fixation- bacteria convert nitrogen gas

to a form of nitrogen that the plants can use– Good bacteria in foods– E. coli in our intestines