Bacteria

BACTERIA

1. Classified into two kingdoms: -- Eubacteria (true bacteria) -- Archaebacteria (Ancient Bacteria).

2. are microscopic Prokaryotes.  (“before nucleus”)3. Adapted to living in all environments (even some extreme)

– they exist EVERYWHERE

1. Cell wall – keeps cell from bursting or collapsing due to osmotic changes (changes in water)

a. The cell wall may also be surrounded by an organized capsule called a glycocalyx and/or by a loose jelly-like sheath called a slime layer. 

b. In parasitic forms, these outer coverings protect the cell from host defenses.

5.  Nucleoid region contains a circular loop of DNA

6.  Plasmids are rings of DNA, used in reproduction

7.  Ribosomes in cytoplasm synthesize proteins

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!

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

What are the two blank areas?

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

DNA makes a copy of itself, then cell splits

II.  Reproduction in Prokaryotes

a. Conjugation occurs when a bacterium

passes DNA to a second bacterium through a tube (sex pilus)

temporarily joins two cells; this occurs only between bacteria in the same or closely related species. 

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

TRANSFORMATION

a. In transduction, bacteriophages (types of viruses) transfer portions of bacterial DNA from one cell to another. o Plasmids are separate pieces

of DNA that can replicate on their own

o they 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.

Bacteria differ in their need for, and tolerance of, oxygen (O2).

1.Obligate anaerobes are unable to grow in the presence of O2; this includes anaerobic bacteria that cause botulism, gas gangrene, and tetanus.2.Facultative anaerobes are able to grow in either the presence or absence of gaseous O2.3.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

Autotrophic (self-feeding) Prokaryotes

1.Photoautotrophs are photosynthetic and use light energy to assemble the organic molecules they require.2.Chemoautotrophs make organic molecules by using energy derived from the oxidation of inorganic compounds in the environment. (methanogens)

THERMOACIDOPHILE – thrives in super-hot, super-acidic conditionsthe red stuff on the rocksThis is an archaebacteria.

THE FUTURE BELONGS TO ARCHAE!

Heterotrophic (feeds on other things) Prokaryotes

•Most free‑living bacteria are chemoheterotrophs that take in pre-formed organic nutrients, meaning they feed on other living or decaying things.•There is probably no natural organic molecule that cannot be broken down by some prokaryotic species. •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 (Gram-positive) or thin (Gram-negative) cell wall.

Gram Negative

Gram Positive

Bacteria Shapes

Cocci – spheres

Bacilli – rods

Spirilla - spirals

Staph – in clusters

Strep – in chains

Streptococcus (spheres in chains)

This is the bacteria that causes strep throat.

Identify Gram positive or Gram negative ?Identify shape as bacillus, cocci or spirilla?

Identify Gram positive or Gram negative ?Identify shape as bacillus, cocci or spirilla?(Anthrax)

Identify as Gram positive or Gram negative?

Staphylococcus

Identify as Streptococcus or Staphylococcus?

Strains are responsible for strep throat, and flesh eating bacteria

Identify as Streptococcus or Staphylococcus?

Staph means “bunch of grapes” in Greek.

Identify as cocci, bacillis or spirilla?

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 infectionAlso 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)

E. Coli – what is the long thing at the end of each bacterium called?

Cocci, Bacillis or Spirilla Bacteria?

Salmonella

Name this Bacteria:(staphyl or strepto? coccus, bacillus or spirilla?)

Culturing Bacteria