Bacterial spores and their arrangements

Endospores: (spores) are a dormant form of bacterial cell produced by certain bacteria when starved; the actively growing form of the cell is referred to as vegetative. The spore is resistant to adverse conditions like ultraviolet and gamma radiation, desiccation, lysozyme, temperature, starvation, and chemical disinfectants. They are commonly found in soil and water, where they may survive for long periods of time. Endospores can be destroyed by burning or autoclaving at 120°C for 15 mins.
These spores are commonly found in the genera Bacillus and Clostridium (both Gram positive). The position of the endospore differs among bacterial species. The main types within the cell are Terminal endospores,Central endospores,Subterminal endospores and Lateral endospores.

Resistance mechanism is by:
• Formation of new enzymes e.g. heat resistant catalase
• Increase or decrease in other enzymes level
• Dehydration containing calcium dipicolinate (dipicolinic acid) in the core
• Keratin spore coat layer

The staining techniques used are Moeller stain (the endospore shows up as red, while the rest of the cell stains blue) and Schaffer-Fulton stain (the endospore stains green and bacterial bodies red).
Reactivation of the endospore occurs when conditions are more favourable and involves activation, germination, and outgrowth.


Names & Roll No. – 2006MO38. Sophie Gorniewicz