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Bacteria produce a single endospore internally. The spore is sometimes surrounded by a thin covering known as the exosporium, which overlies the spore coat. The spore coat, which acts like a sieve that excludes large toxic molecules like lysozyme, is resistant to many toxic molecules and may also contain enzymes that are involved in germination.
Spores form part of the life cycles of many plants, algae, fungi and protozoa. [2] They were thought to have appeared as early as the mid-late Ordovician period as an adaptation of early land plants. [3] Bacterial spores are not part of a sexual cycle, but are resistant structures used for survival under unfavourable conditions. [4]
Endospore-forming bacteria can cause disease; for example, anthrax can be contracted by the inhalation of Bacillus anthracis endospores, and contamination of deep puncture wounds with Clostridium tetani endospores causes tetanus, which, like botulism, is caused by a toxin released by the bacteria that grow from the spores. [101]
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 ...
Cell shape is generally characteristic of a given bacterial species, but can vary depending on growth conditions. Some bacteria have complex life cycles involving the production of stalks and appendages (e.g. Caulobacter) and some produce elaborate structures bearing reproductive spores (e.g. Myxococcus, Streptomyces).
A 2009 study compared the density of spores found in soil (about 10 6 spores per gram) to that found in human feces (about 10 4 spores per gram). The number of spores found in the human gut was too high to be attributed solely to consumption through food contamination. [15] In some bee habitats, B. subtilis appears in the gut flora of honey ...
Endospore staining is a technique used in bacteriology to identify the presence of endospores in a bacterial sample. [1] Within bacteria, endospores are protective structures used to survive extreme conditions, including high temperatures making them highly resistant to chemicals. [ 2 ]
Some bacteria also produce endospores with an exosporium, of which the most commonly studied are Bacillus species, particularly Bacillus cereus and the anthrax-causing bacterium Bacillus anthracis. The exosporium is the portion of the spore that interacts with the environment or host organism, and may contain spore antigens. [1]