The sporulation starts in conditions unfavourable for the growth due to starvation, desiccation, high temperature etc. The endospore formation does not take place during active phase of growth. In some species (Bacillus thuringiensis), it is covered by an additional covering, called exosporium or exosporium basal layer, which is apparently loose. It is covered by a thick layer, the cortex and then a multilayered thin and tough outer spore coat, which may be differentiated into outer and inner coat layer. The core is covered by a thin membrane, called core membrane or inner membrane or germ cell membrane, from which the cell wall of future vegetative bacterium develops. The core is mainly composed of DNA, ribosome, t-RNA, enzymes etc. In diameter, it may be the same or wider (Clostridium) or less (Bacillus) than the width of the specific bacterial cell.Įndospore consists of a central protoplast, the core (Fig. The position of spore may be central, subterminal or terminal (Fig. The position, relative size and shape remain constant in a particular species. Spores may be oval or spherical in shape. (i) Obligate aerobes, e.g., Bacillus subtilis, B. On germination, it gives rise to a bacterial cell. Only one spore is formed in a bacterial cell. As the spores are formed within the cell, they are called endospores. Spores are formed during unfavourable environmental condition like desiccation and starvation. These are the resting structure and during favourable condition they again behave as the mother, e.g., many members of Azotobacter. Cysts:Ĭysts are formed by the deposition of additional layer around the mother wall. This outgrowth is the bud, which gets separated from the mother by partition wall, e.g., Hyphomicrobium vulgare, Rhodomicrobium vannielia, etc. Simultaneously the nucleus undergoes division, where one remains with the mother and other one with some cytoplasm goes to the swelling. The bacterial cell develops small swelling at one side which gradually increases in size (Fig. After detachment from the mother and getting contact with suitable substratum, the conidium germinates and gives rise to new mycelium. The part of this filament which bears conidia is called conidiophore. It does not store any personal data.Conidia formation takes place in filamentous bacteria like Streptomyces etc., by the formation of a transverse septum at the apex of the filament (Fig. The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. The cookie is used to store the user consent for the cookies in the category "Performance". This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other. The cookies is used to store the user consent for the cookies in the category "Necessary". The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". The cookie is used to store the user consent for the cookies in the category "Analytics".
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