Page 37 - MNU microbiology theoritical 2025

General Microbiology & Immunology (PM 401) Second level Semester 4 2024/2025

Endospores

• Bacterial cells are generally observed as vegetative cells, but some genera of

bacteria have the ability to form endospores.

• An endospore: is a unique type of dormant cell produced by a process called

sporulation within cells of certain bacterial species

• The ability to form endospores is restricted to a few genera of Gram-positive

bacteria.

➢ Bacillus

➢ Clostridium.

• The structures may remain dormant for perhaps 100 years, or even longer,

• Endospores (not to be reproduction method) allow some bacterial cells to

survive:

- long periods without food or water

- exposure to chemicals, extreme temperatures, and even radiation

Sporulation
It generally begins when nutrients become depleted or

environmental conditions become otherwise

unfavorable.
• Vegetative growth stops, DNA is duplicated

• A septum forms between the two chromosomes,
dividing the cell asymmetrically.

• The larger compartment then engulfs the smaller

compartment, forming a forespore within a mother

cell

General Microbiology & Immunology (PM 401) theoretical handbook Page 26