BACTERIA



BACTERIA

A.Two Kingdoms

1. Kingdom Eubacteria (most of the bacteria

we know)

2. Kingdom Archaebacteria

(the EXTREME BACTERIA)

a. Thermophiles – heat tolerant e.g.

Near undersea volcanic vents

[pic][pic]

Thermophilic Bacteria Halophilic bacteria

b. Halophiles – salt tolerant

e.g. Great Salt Lake is 10-15% NaCl

B. General Information

1. Structure:

A. prokaryotic (no nucleus)

B. uni-cellular

C. cell walls

D. genetic code = DNA , single circular chr.

2. Ubiquitous = they are everywhere

3. Most diverse habitats of all living organisms

C. Structure

1. 2 types of Cell wall

– can be identified by Gram Stain reaction

a. Gram positive (positively purple) THICK layer of peptidoglycan (protein) in cell wall

[pic]

Gram Positive Bacteria

b. Gram negative (pink) THIN layer of petidoglycan in cell wall

[pic]

Gram Negative Bacteria

c. Gram stain tells which antibiotics will work against it

[pic]

Gram Positive vs. Gram Negative Bacteria

2. Capsule – may or may not be present-

(have capsule = antibiotics do NOT work

as well)

Bacterial Capsule

3. Pili

a. Short hair-like projections

b. f(x)s=

1). attachment to host

2). conjugation (sexual reproduction)

[pic]

Bacterium Diagram

4. Endospores

a. formed under STRESS (bad conditions)

b. Thick walled outside with DNA inside

c. Can grow after many years

(some 1300 yr. old anthrax spores grew)

[pic]

Bacterial Endospore

5. Shapes

a. Coccus– spherical cocci (plural)

[pic]

Cocci

b. Bacillus-rod-shaped bacilli (plural)

[pic]

Bacilli

c. Spirillum- spiral shaped spirilli (plural)

[pic]

Spirilli

6. Groupings of Bacteria

a. diplo- two

b. strepto- chain

c. staphylo- cluster / clump

[pic]

Groupings of Bacteria

7. Bacterial Reproduction

a. Asexual- binary fission

❖ only 1 needed

❖ no genetic diversity

❖ good for rapid repopulation

[pic]

Bacterial Binary fission

b. Sexual - conjugation

❖ takes two

❖ genetic diversity

❖ allows bacteria to transfer antibiotic resistance between species

8. Classification of Bacteria

a. Gram Staining

b. Shape & Groupings

c. How they obtain ENERGY

1). Photosynthetic (SUN)

eg. Anabena fixes nitrogen into the soil

[pic]

2).Chemo – autotrophic (“eat”

chemicals)

➢ Some “eat” : NH3 (ammonia)

H2S (hydrogen sulfide)

[pic]

Sulfide –eating bacteria

➢ Some make CH4 (methane) …..methanogens

[pic]

Methanogens

3). Heterotrophic (“other” feeding) eat others

4). Aerobes - must have oxygen

5). Anaerobes - oxygen kills them

eg. Clostridium tetani (tetanus)

Clostridium botulinum (botulism)

6). Faculative anaerobes –

can live with or with out oxygen

9. Controlling Bacteria

a. Antibiotics

1). How do they work?

Rupture cell walls or prevent protein synthesis

2). Increases animal life expectancy

➢ Greatly reduces the infant mortality rate

➢ Fight diseases, save lives

[pic]

b. Sterilization

1). Heat kills bacteria

2). Chemicals used to kill bacteria

[pic][pic][pic]

c. Food Handling &Processing

1). Keep foods cold enough or hot enough to

prevent bacterial growth

(cook, steam, boil, freeze)

2). Can / preserve with:

salt, sugar, vinegar, & heat )

[pic][pic][pic]

d. Irradiation for preservation

10. How are bacteria pathogens?

(disease causing agent)

a. Metabolise (eat) or lyse (blow up) host cells (cell, tissue damage)

b. Secrete toxins (poisons)

c. Food poisoning examples

1). Salmonella - undercooked chicken, eggs

2). Staphylococcus aureus - wrestling mats

3). Clostridium botulinum - canned goods

4). Eschericia coli - undercooked beef

11. Helpful Bacteria

a. Nitrogen fixation on plant roots (legumes)

(plants need nitrogen to live! & all animals need plants to live…)

b. Food production eg. yogurt, cheese, pickles,

sauerkraut, wine, vinegar, olives

[pic]

[pic][pic][pic]

c. Industrial/ other uses

• Mining

• Oil spill clean up (bioremediation)

• Water purification

[pic]

Water treatment plant

• Synthesis of drugs & other genetic engineering e.g. insulin

• Snow making (helps tourism)

[pic]

Snow making

d. Symbiosis

• Cellulose digesters in cattle guts

[pic]

Cows grazing

• E. coli in human large intestine

[pic]

E. coli in your gut helps digest food and make vitamins

12. Harmful Bacteria

a. Pathogens (cause disease)

e.g. strep, tetanus, bubonic plague,

anthrax, smallpox, Lyme disease

b. Food poisoning e.g. Salmonella, Staph,

Botulism, E. coli

c. Bioterrorism –E.g. anthrax, Botulism

13.

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pilus

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