The compound is then purified by one chromatographic step followed by crystallization. Compared to the semisynthesis method, PCF eliminates the need for many hazardous chemicals and saves a considerable amount of energy.In 1993, paclitaxel was discovered as a natural product in a newly described endophytic fungus living in the yew tree. It has since been reported in a number of other endophytic fungi, including Nodulisporium sylviforme, Alternaria taxi, Cladosporium cladosporioides MD2, Metarhizium anisopliae, Aspergillus candidus MD3, Mucor rouxianus, Chaetomella raphigera, Phyllosticta tabernaemontanae, Phomopsis, Pestalotiopsis pauciseta, Phyllosticta citricarpa, Podocarpus sp., Fusarium solani, Pestalotiopsis terminaliae, Pestalotiopsis breviseta, Botryodiplodia theobromae, Gliocladium sp., Alternaria alternata var. monosporus, Cladosporium cladosporioides, Nigrospora sp., Pestalotiopsis versicolor, and Taxomyces andreanae. However, there has been contradictory evidence for its production by endophytes, with other studies finding independent production is unlikely. Biosynthesis
Taxol is a tetracyclic diterpene, and the biosynthesis of diterpenes starts with a FPP molecule being elongated by the addition of an IPP molecule in order to form geranylgeranyl diphosphate (GGPP). The biosynthesis of Taxol contains nineteen steps. These 19 steps can be considered in several steps, with the first step being the formation of the taxane skeleton, which then undergoes a series of oxygenations. Following the oxygenations, two acetylations and a benzoylation occur on the intermediate. The oxygenation of the taxane core is believed to occur on C5 and C10, C2 and C9, C13 followed by C7, and a C1 hydroxylation later on in the pathway.
Traumatic alopecia is a cutaneous condition that results from the forceful pulling out of the scalp hair. See also
Traction alopecia
List of cutaneous conditions


== References ==