Spores (copy)

Spores

Formed within the cell and are highly resistant to heat, desiccation, radiation, chemicals, and some disinfectants.

Primary function of Spores

Ensure the survival during harsh environmental conditions (overpopulation, nutrient deficiency, or unfavorable climatic conditions)

Types of Spores

Endospores

Exospores

Exospores

Produced in the eukaryotic cells of fungi, algae, and cyanobacteria

Endospores

Common type of spores produced mainly by bacteria

Endospores are

protective and metabolically inactive structures

they do not play a role in reproduction

produced via sporulation

Sporulation steps

1. DNA replicates

2. Membrane form around DNA

3. Forespore forms additional membranes

4. Protective cortex forms around the spore

5. Protein coat forms around the cortex

6. Spore is released

Sporulation detailed step 1

Cell stops growing; DNA is duplicated.

Sporulation detailed step 2

A septum forms, dividing the cell asymmetrically

Sporulation detailed step 3

The larger compartment engulfs the smaller compartment, and the components that will make up the endospore start forming

Sporulation detailed step 4

The smaller compartment develops into a forespore and peptidoglycan-containing material forms between that and the mother cell

Sporulation detailed step 5

The mother cell is degraded and the endospore released.

Vegetative cells

Referred to as a sporangium that produces the endospore within itself

Outer protein coat of endospores

Protects DNA, some ribosomes, RNA, and enzymes from harsh conditions

Endospores exposed to favorable conditions

Germinate to produce vegetative cells.

Few genera of bacteria that produce endospores

Bacillus & Clostridium

Bacillus

1. most are soil, freshwater, and marine saprophytes

2. notable pathogens

Clostridium

1. most are soil or aquatic saprophytes

2. some inhabit the human intestine

Bacillus notable pathogen

Bacillus anthracis - causes anthrax

3 Clostridium notable pathogens

Clostridium tetani - tetanus

Clostridium botulinum - botulism

Clostridium difficile - pseudomembranous colitis