Introduction to Bacteria

Ubiquity of Bacteria Ubiquity [yoo-bik-wi-tee] : the state or capacity of being everywhere The ubiquity of bacteria refers to the concept that microorganisms are EVERYWHERE Bacteria are the most widely distributed organisms in the biosphere. Soil, water, air Normal flora: microorganisms that live on and in our body that do not cause harm Only place where bacteria are not found in the body are in areas that are purposely made sterile (Remember Pasteur’s efforts to make medium stay clean?????) Some Body fluids (pancreatic, bile, cerebrospinal, kidney filtrate) Clean rooms Sterilized/autoclaved equipment

What makes an organism a bacterium? Bacteria are easily defined by their cellular structure and size Lacks a defined nucleus that is surrounded by a nuclear membrane (only a little DNA; no need for over-organization) Lack complex organelles (i.e. mitochondria) Cell wall contains peptidoglycan Approximately 0.5-2 μm in diameter by comparison, the average red blood cell is 6-8 μm

Handling Bacterial Cultures Aseptic technique: keeps unwanted microorganisms out (reduces contamination) Purpose: keep the area clean; helps keep the culture clean Disinfecting work area All tools used to handle bacteria need to be sterile Loops/Needles: flamed in the incinerator to sterilize Tubes, plates, and any other tools: autoclaved/irradiated to kill any existing bacteria Keep all cultures covered until ready for use Be aware of your area-if you are unsure if your tools have been compromised, then start over

Characterizing Microorganisms I’m Lonely!! Binary Fission Colony

Characterizing Microorganisms Colony morphology Form: surface view Elevation: height Margin: edge Color Smell Cell morphology Size Shape Gram stain reaction Acid-fast reaction

Be sure you can tell the morphology of each organism Look over Slides #4-11 Be sure you can tell the morphology of each organism Bacillus/rod, cocci, vibrio/curved, spirochete Know the correct spelling and nomenclature of each microorganism There are pictures of the slides on the website http://biology-irsc.weebly.com/mcb2010l-microbiology-lab.html

Shapes of Bacteria Bacillus (bacilli) short bacilli Pseudomonas Shapes of Bacteria Bacillus (bacilli) generic term to describe the morphology of any rod-shaped bacterium (one axis much different than another). long bacilli Bacillus Bacillus with endospores (endospore stain)

Shapes of Bacteria Coccus (cocci) any bacterium that has a spherical, ovoid, or generally round shape cocci in chains Streptococci cocci in clusters Staphylococci

Shapes of bacteria Vibrio Possessing a curved-rod shape (comma shape)

Shapes of bacteria Spirochete Possessing a helical/corkscrew shape Treponema pallidum, Borrelia burgdorferi