Natural fiber exoskeletons of insects and arthropods. In shells and exoskeletons, the chitin fibers contribute to their hierarchical structure. In nature, pure chitin (100% acetylation) does not exist. It instead exists as a copolymer with chitin's deacetylated derivative, chitosan. When the acetylized composition of the copolymer is over 50% acetylated it is chitin. This copolymer of chitin and chitosan is a random or block copolymer. Chitosan is a deacetylated derivative of chitin. When the acetylized composition of the copolymer is below 50% it is chitosan. Chitosan is a semicrystalline “polymer of β-(1-4)-2-amino-2-deoxy-D-glucose”. One difference between chitin and chitosan is that chitosan is
Glial cell line-derived neurotrophic factor Vitamin D potently induces GDNF expression. Exposure of dopaminergic-like cell line to Ibogaine HCl results in an increase in GDNF mRNA, leading to protein expression and to the corresponding activation of the GDNF signaling pathway. This, in turn, leads to a further increase in the mRNA level of the growth factor through a feed-back loop. It was also found that ibogaine metabolite, noribogaine, also possess the ability to increase GDNF levels. Glial cell line-derived neurotrophic factor Glial cell-derived neurotrophic factor (GDNF) is a protein that, in humans, is encoded by the "GDNF" gene. GDNF is a small protein that potently