BACTERIAL ENDOSPORE

1. BACTERIAL ENDOSPORE
BY:
E.PRIYA
BP221503
I-M. SC APPLIED MICROBIOLOGY

2. ENDOSPORE
 Endospore are the resisting non reproductive structure formed by bacteria for the
survival during adverse environmental condition
 It was First discovered by john Tyndall
 He discovered the endospore producing bacteria after heating at 100⸰C
 Endospore are structurally, metabolically and functionally different from
vegetative cells
 Endospore are commonly found in soil and water, where they may survive for
long period of time

3. STRUCTURE OF ENDOSPORE
 The structure of endospore is very complex and they possess multilayer
covering
 The outermost layer of the spore is called as Exosporium which is relatively
thin and delicate
 Beneath the Exosporium is a spore coat composed of several layer of
proteins
 Spore coat is comparatively thick. The thickness of the spore coat is one
reason for the high resistance of endospore towards heat, radiation and
chemicals.

4.  Inert to the spore coat is cortex. It is the thicker wall layer in the endospore
 Cortex is very large and sometimes occupy as much as half of the spore
volume
 The cortex is composed of peptidoglycan. The peptidoglycan in the cortex
is less cross linked than that of vegetative cells
 The innermost layer of the spore is called the spore cell or core cell wall
 Spore cell wall cover the central protoplast

5.  The endospore core has a normal cell structure as that of a vegetative
cells
 The core contain ribosomes and centrally placed nucleoid (genetic
material DNA)
 The core only contain about 10-25%of water of the normal vegetative cells.

7. ENDOSPORE PRODUCTING BACTERIA
 Endospore production is associated with Gram Positive bacteria (Gram
positive rods) only and the Endospores are not produced by Gram
negative bacteria.
 A few genera of bacteria produce Endospore such as Clostridium sp.
(Gangrene) and Bacillus sp. (Anthrax), both of them are Gram positive rods.
 Other genera of bacteria, including Desulfotomaculum, Sporolactobacillus,
Sporosarcina, Oscillospira and Thermoactinomyces are also able to
produceEndospores.
 Since not all bacteria form Endospores, so we can use the presence of
Endospores as an identification factor.

8. FUNCTIONS OF ENDOSPORES
 Endospores are ultimately protection for the bacterial genome.
 Spores form within the cell and contain a full copy of the bacterium’s
genome.
 Endospores provide resistance against
a) Heat
b) Boiling
c) Drying
d) Antibiotics

9. e) Low nutrient conditions
f) Radiation
g) Osmotic pressure
h) Various chemical disinfectants

10. SPORULATION OF SPOROGENESIS

11. DIFFERENCE BETWEEN VEGETATIVE CELLS AND
ENDOSPORES