certain bacteria produce structure called endospores during the process called the sporulation . endospore are differentiated cells that are highly resistance to heat and are difficult to destroy, even by harsh chemical or radiation. it can survive up to 150centrigrade.
mostly found in soil and the bacillus and the clostridium are the best studied genera of endospore forming bacteria.
- strongly refractile structure seen under the microscope and impermeable to dye and unstained.
- the structure of the endospore as seen in the electronmicroscope differ differently from the vegetative cell.
- endospore is str. more complex in that it has may layers that are absent from the vegetative cell.
- the outermost layer is called the exosporium , a thin layer covering within this are the spore coat, composed of layer of specific spore specific protein.
-below the spore coat is the cortex, which consist of the loosely cross-linked peptidoglycan , and inside the cortex is the core portion which consists of the core wall, cell membrane, cytoplasm, nucleus etc.
-dipicolonic acid is found in the edospore forming all the bacteria rather than the vegetative cell.
-the dipicolonic acid is found cross linked with the calcium ion in the core which make 10%of the dry weight of the endospore.
-the complex calcium dipicolonic acid reduce the availability of water within the endospore, thus helping in the dehydrating with the endospore.
-it also intercalates in dna, to stablized it from the denaturation.
-it contain 10- 25%of the water content of the vegetative cell.
-the ph of the endospore is one unit less than of the vegetative cell of the cytoplasm.
-the endospore also contain the sasp( small acids soluble proteins) which tightly bound to the dna and stablized it from the normal B form to the A form. which is more resistant to the formation of pyrimidine dimer by uv radiation.
-in addition sasp also has the function as the carbon source and energy source for the growth of a new mos.(vegetative)cell from the endospore, a process called the germination.
- reference: Brock biology of microorganism, 11th edition
mostly found in soil and the bacillus and the clostridium are the best studied genera of endospore forming bacteria.
- strongly refractile structure seen under the microscope and impermeable to dye and unstained.
- the structure of the endospore as seen in the electronmicroscope differ differently from the vegetative cell.
- endospore is str. more complex in that it has may layers that are absent from the vegetative cell.
- the outermost layer is called the exosporium , a thin layer covering within this are the spore coat, composed of layer of specific spore specific protein.
-below the spore coat is the cortex, which consist of the loosely cross-linked peptidoglycan , and inside the cortex is the core portion which consists of the core wall, cell membrane, cytoplasm, nucleus etc.
-dipicolonic acid is found in the edospore forming all the bacteria rather than the vegetative cell.
-the dipicolonic acid is found cross linked with the calcium ion in the core which make 10%of the dry weight of the endospore.
-the complex calcium dipicolonic acid reduce the availability of water within the endospore, thus helping in the dehydrating with the endospore.
-it also intercalates in dna, to stablized it from the denaturation.
-it contain 10- 25%of the water content of the vegetative cell.
-the ph of the endospore is one unit less than of the vegetative cell of the cytoplasm.
-the endospore also contain the sasp( small acids soluble proteins) which tightly bound to the dna and stablized it from the normal B form to the A form. which is more resistant to the formation of pyrimidine dimer by uv radiation.
-in addition sasp also has the function as the carbon source and energy source for the growth of a new mos.(vegetative)cell from the endospore, a process called the germination.
- reference: Brock biology of microorganism, 11th edition
