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) u Bacterial Flagellum u Pili- short, thin appendages

Bacteria E. coli

Nutrition-DO NOT NEED TO COPY u Autotrophs- manufacture organic compounds –Photoautotrophs- use light energy & CO 2 –Chemoautotrophs-use inorganic substances like H 2 S, NH 3, and other nitrogen compounds u 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 u obligate aerobes- must have oxygen u obligate anaerobes- cannot live in oxygen u facultative anaerobes- can grow with or without oxygen

2 Bacteria Kingdoms u Kingdom Archaebacteria - are ancient bacteria that live in extreme environments u 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: u do not have peptidoglycan in their cell walls u have ribosomes similar to eukaryotes u have unique lipids in their plasma (cell) membranes

The Archaebacteria also: u have some genes that resemble eukaryotic genes u usually are not pathogenic (they don’t usually make us sick!) u live in extreme environments: –high concentrations of salt –extremes of pH and temperature

3 Archaebacterial Groups u Methanogens-turn H 2 and CO 2 into methane u Halophiles-salt u Thermoacidophiles = live in extremely hot, acid environments

Methanogens u anaerobic bacteria that get energy by turning H 2 and CO 2 into methane u live in mud, swamps, and the guts of cows, humans, termites and other animals

Halophiles u 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!) u halophile means “salt loving” u most halophiles are aerobic and heterotrophic

Diversity of Halophilic Organisms u halophiles are found in salt lakes, salt marshes, subterranean salt deposits, dry soils, salted meats u the Red Sea was named after the halobacterium that turns the water red during massive blooms.

Halophile Environments Owens Lake, Great Salt Lake, coastal splash zones, Dead Sea

Thermoacidophiles u Like temperature and pH extremes –Hot = up to 3740ºF –Cold = down to 34ºF –Acid = pH 2 –Basic = pH 9 u they are chemoautotrophs u the first Extremophile was found about 30 years ago

Extreme Temperatures u Thermophiles - High temperature = C –Thermal vents and hot springs –May go hand in hand with chemical extremes u Psychrophiles - Low temperature –Arctic and Antarctic »Most rely on photosynthesis

Thermophile Environments Hydrothermal Vents in the ocean, and Obsidian Pool in Yellowstone National Park

Psychrophile Environments Alan Hills Ice Field: Antarctica

Chemical Extremes u Acidophiles - Acidic –Again thermal vents and some hot springs u Alkaliphiles - Alkaline –Soda lakes in Africa and western U.S. u 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 u The bacterium pseudomonas was found living on a desert plant in the Negev Desert. The plant secretes salt through salt glands on its leaves. u 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 u Baccili u Cocci u Spirillum

Identification – cell walls u There is a method used to tell apart two types of cell walls in eubacteria, called Gram staining. u Gram-positive bacteria stain violet –These bacteria have 1 cell membrane surrounded by a thick peptidoglycan wall which holds the color well. u 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 u Bacteria produce disease in 1 of 2 ways: –Damage cells and tissues of the organisms it is infecting by breaking down the cells for food. Example- tuberculosis OR –Releasing toxins that will travel throughout the body, which interfere with the normal activity of the infected organisms cells. Example- strep throat

Preventing bacterial disease u Vaccines- injection of a weakened form of a pathogen that prepares the body to produce immunity to the pathogen u Antibiotics- given after infection, they block the growth and reproduction of bacteria

Controlling bacteria u 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! u 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