Translations:Sporulation in Bacillus subtilis/1/en

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Figure Caption: The Bacillus subtilis (Stage I) in vegetative growth is in unfavorable conditions, so it begins the process of sporulation. Examples of unfavorable conditions are an environment that lacks the required nutrients, is too hot, or too cold. Asymmetric (unequal) division occurs from the tightening of the Z-ring (Stage II). The Z-ring is multiple FtsZ proteins assembled into a ring that depolymerizes to cause an inward constriction, which will form the septum that results in two daughter cells. The mother cell, which is the bigger of the two daughter cells, engulfs the pre-spore (Stage III). Next, the cortex (Stage IV) and the coat (Stage V) form around the spore. The cortex is made of peptidoglycan and the coat is composed of several layers of specific proteins. Once the spore is mature, the cell lyses (Stage VI and VII). Thus, a free endospore is formed that can withstand harsh environments. This endospore can later germinate into a vegetative cell. Vegetative cycle occurs in favorable conditions, such as nutrient abundance and a moderate temperature. This is a cycle of medial division and growth creating more vegetative Bacillus subtilis.
Fig1. The sporulation process of Bacillus subtilis

Bacillus subtilis is a rod-shaped, Gram-positive bacteria that is naturally found in soil and vegetation, and is known for its ability to form a small, tough, protective and metabolically dormant endospore. B. subtilis can divide symmetrically to make two daughter cells (binary fission), or asymmetrically, producing a single endospore that is resistant to environmental factors such as heat, desiccation, radiation and chemical insult which can persist in the environment for long periods of time. The endospore is formed at times of nutritional stress, allowing the organism to persist in the environment until conditions become favourable. The process of endospore formation has profound morphological and physiological consequences: radical post-replicative remodelling of two progeny cells, accompanied eventually by cessation of metabolic activity in one daughter cell (the spore) and death by lysis of the other (the ‘mother cell’).