Bacterial spore
![bacterial spore bacterial spore](http://microbeonline.com/wp-content/uploads/2013/04/Spore-of-Clostridium-botulinum.png)
The tap water removes only the excess primary stain present in the surrounding of the spores. When the spores are treated with the decolourising agent, tap water, they do not undergo decolourisation, as they exclude water. Therefore, penetration of the primary stain is augmented by the application of heat, which drives it through the covering layers into the spore protoplast.
![bacterial spore bacterial spore](https://thumbs-prod.si-cdn.com/JA4Kud7A0HGdgHKOBe8FenAt510=/fit-in/1600x0/https://public-media.si-cdn.com/filer/3f/56/3f56ad44-e874-4752-9383-c65c7bea0617/istock_000021193853_large.jpg)
The primary stain, malachite green, cannot penetrate into the spores through these layers.
![bacterial spore bacterial spore](https://media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41598-018-29879-5/MediaObjects/41598_2018_29879_Fig4_HTML.png)
The spores are different from the vegetative cells in that they possess thick, relatively impervious layers around them (Figure 2.14). Spore staining is also helpful in identification of the bacteria belonging to the genera Bacillus, Clostridium and Desulfotomaculum. The purpose of spore staining is to differentiate the spores and vegetative cells of a spore-former and to differentiate spore-formers from non-spore-formers. The spore gains its resistance by several mechanisms, which have not yet been clearly explained.Ī bacteria, which cannot produce a spore and therefore, dies in its vegetative form under adverse environmental conditions, is a non-spore-forming bacteria (non-spore-former). The spore has thick, relatively impervious layers, such as spore cortex and spore coat, which protect the cell from any physical damage. The process of spore formation is called ‘sporogenesis’. If adverse conditions worsen, the cell ruptures, releasing the endospore, which now becomes an independent dormant cell called ‘spore’. This spore, formed inside the bacteria cell, is called ‘endospore’ (Figure 2.13). In adverse conditions, a spore is produced within a vegetative cell by dehydration and contraction of its cell contents. However, few species of bacteria, can survive under such adverse conditions by changing themselves to highly resistant, metabolically inactive forms called ‘spores’. On the other hand, most of them die, when the environmental conditions become adverse, such as, severe cold, extreme heat, ageing, lack of nutrients, exposure to radiation and toxic chemicals.