BACTERIA

Just keep swimming .....video 1. Bacteria are classified into two kingdoms: Eubacteria (true bacteria) and Archaebacteria (Ancient Bacteria). 2. BACTERIA are microscopic Prokaryotes.  (“before nucleus”) 3. Adapted to living in all environments (even some extreme) – they exist EVERYWHERE Just keep swimming .....video

a. The cell wall may be surrounded by an organized capsule called a glycocalyx and/or by a loose gelatinous sheath called a slime layer.  b. In parasitic forms, these outer coverings protect the cell from host defenses. 1. Outside the plasma membrane of most cells is a rigid cell wall that keeps the cell from bursting or collapsing 

Bacteria Structure 2. Flagella is used for movement 3.  Pilli (Fimbrae) help bacteria cling to surfaces 4. Prokaryotes do not have organelles or a membrane bound  nucleus! 5.  Nucleoid region contains a circular loop of DNA 6.  Plasmids are rings of DNA, used in reproduction 7.  Ribosomes in cytoplasm synthesize proteins

Cell Membrane – regulates what comes in and out of the cell Cell Wall – maintains shape and form Capsule – found in virulent bacteria, helps evade immune system

II.  Reproduction in Prokaryotes Binary fission is the splitting of a parent cell into two daughter cells; it is asexual reproduction in prokaryotes.  I

In bacteria, genetic recombination can occur in three ways. a In bacteria, genetic recombination can occur in three ways.  a. Conjugation occurs when a bacterium passes DNA to a second bacterium through a tube (sex pilus) that temporarily joins two cells; the plasmid (DNA) is then exchanged

b.Transformation involves bacteria taking up free pieces of DNA secreted by live bacteria or released by dead bacteria. 

c. In transduction, bacteriophages transfer portions of bacterial DNA from one cell to another. Plasmids can carry genes for resistance to antibiotics and transfer them between bacteria by any of these processes

Plasmid – an extra bit of DNA, used in sexual reproduction Plasmids are also used in genetic engineering Some bacteria form resistant endospores in response to unfavorable environmental conditions.

TRANSFORMATION

III. Prokaryotic Nutrition   1.   Bacteria differ in their need for, and tolerance of, oxygen (O2). a.   Obligate anaerobes are unable to grow in the presence of O2; this includes anaerobic bacteria that cause botulism, gas gangrene, and tetanus. b.   Facultative anaerobes are able to grow in either the presence or absence of gaseous O2. c.   Aerobic organisms (including animals and most prokaryotes) require a constant supply of O2 to carry out cellular respiration. staphylococcus is a gram-positive, facultative anaerobe

2. Autotrophic Prokaryotes a.   Photoautotrophs are photosynthetic and use light energy to assemble the organic molecules they require. b.   Chemoautotrophs make organic molecules by using energy derived from the oxidation of inorganic compounds in the environment. (methanogens) Check out the virus and bacteria gallery

THERMOACIDOPHILE – the red stuff on the rocks This is an archaebacteria. THE FUTURE BELONGS TO ARCHAE!

3.   Heterotrophic Prokaryotes a.    Most free living bacteria are chemoheterotrophs that take in pre-formed organic nutrients. b.    As aerobic saprotrophs, there is probably no natural organic molecule that cannot be broken down by some prokaryotic species. c.    Detritivores (saprophytic bacteria) are critical in recycling materials in the ecosystem; they decompose dead organic matter and make it available to photosynthesizers. Bacteria have an important role to play in breaking down materials in the environment. Some are harmful and break down material we'd rather keep, like this image of an infection of necrotizing fasciitis (flesh-eating bacteria)

Bacteria Shape & Naming The Gram stain procedure (developed in the late 1880s by Hans Christian Gram) differentiates bacteria. a. Gram positive bacteria stain purple, whereas Gram negative bacteria stain pink. b. This difference is dependent on the thick or thin (respectively) peptidoglycan cell wall.

Bacteria Shapes Cocci – spheres Bacilli – rods Spirilla - spirals Staph – in clusters Strep – in chains

Streptococcus

Gram Stain Procedure

Gram Negative

Gram Positive

Identify Gram Negative, Bacillus

Gram Positive, Bacillus (Anthrax)

Identify Gram Positive Staphylococcus

Bacteria and You You will be viewing many types of bacteria with slides and slide viewers.  Your main task is to identify by shape and gram stain.   You will also need to know specific names (and appearance) of bacteria that cause disease in humans. *Don't forget, you can review this presentation online anytime.

Streptococcus Strains are responsible for strep throat, and flesh eating bacteria

Staphylococcus aureus Staph means “bunch of grapes” in greek.

Staph Infection

Bacillus subtilis Easy to grow in the lab, not harmful Gram Positive *this is an example of a "poor" stain, it looks both pink and purple.  Gram staining takes practice

Tetanus Rigid muscles from tetanus infection Also known as “lockjaw”

Clostridium botulism Gram positive Causes food poisoning that is sometimes fatal All forms lead to paralysis that typically starts with the muscles of the face and then spreads towards the limbs.[1] In severe forms, it leads to paralysis of the breathing muscles and causes respiratory failure. In view of this life-threatening complication, all suspected cases of botulism are treated as medical emergencies, and public health officials are usually involved to prevent further cases from the same source.[1]

A form of botulism is used in BOTOX treatments, as it paralyzes the muscles of the face and effectively smooths wrinkles. Results may vary.

Yersinia Pestis The black plague, this bacteria was carried on the fleas of rats.  It was responsible for the deaths of thousands of Europeans from the 8th to the 14th century.

Bacillis Anthracis (Anthrax)

Bacillus (unknown strain)

Mycoplasmas Rickettsia rickettsi Causes pneumonia Rocky Mountain Spotted Fever, carried by ticks

E. Coli

Spirilla Bacteria

Salmonella

Name this Bacteria Answer: Staphylococcus

Plush Germs Syphilis E. Coli

Gonorrhea The Plague (Black Death)

Culturing Bacteria