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Spores are usually haploid and grow into mature haploid individuals through mitotic division of cells (Urediniospores and Teliospores among rusts are dikaryotic). Dikaryotic cells result from the fusion of two haploid gamete cells. Among sporogenic dikaryotic cells, karyogamy (the fusion of the two haploid nuclei) occurs to produce a diploid cell.
The term sporogenesis can also refer to endospore formation in bacteria, which allows the cells to survive unfavorable conditions. Endospores are not reproductive structures and their formation does not require cell fusion or division. Instead, they form through the production of an encapsulating spore coat within the spore-forming cell.
A diagram of C. tetani showing the bacterium alone, with a spore being produced, and the spore alone. Clostridium tetani is a rod-shaped, Gram-positive bacterium, typically up to 0.5 μm wide and 2.5 μm long. [1] It is motile by way of various flagella that surround its body. [1] C. tetani cannot grow in the presence of oxygen. [1]
[1] [2] The name "endospore" is suggestive of a spore or seed-like form (endo means 'within'), but it is not a true spore (i.e., not an offspring). It is a stripped-down, dormant form to which the bacterium can reduce itself. Endospore formation is usually triggered by a lack of nutrients, and usually occurs in Gram-positive bacteria.
C. perfringens can proliferate in foods that are improperly stored due to the spore's ability to survive normal cooking temperatures. The type A toxin of C. perfringens, also known as the CPA is responsible for food poisoning. [46] Clostridium perfringens is the most common bacterial agent for gas gangrene. [47]
The wrong decision can be catastrophic: a vegetative cell will die if the conditions are too harsh, while bacteria forming spores in an environment which is conducive to vegetative growth will be out competed. [3] In short, initiation of sporulation is a very tightly regulated network with numerous checkpoints for efficient control. [citation ...
It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other groups form sporangia at some point in their life cycle. Sporangia can produce spores by mitosis, but in land plants and many fungi, sporangia produce genetically distinct haploid spores by meiosis.
The hypha that creates the sporing (conidiating) tip can be very similar to the normal hyphal tip, or it can be differentiated. The most common differentiation is the formation of a bottle shaped cell called a phialide, from which the spores are produced. Not all of these asexual structures are a single hypha.