Melanins are a family of heterogeneous polymeric pigments that provide ultraviolet (UV) light protection, structural support, coloration, and free radical scavenging. Formed by oxidative oligomerization of catecholic small molecules, the physical properties of melanins are influenced by covalent and noncovalent disorder. We report the use of tyrosine-containing tripeptides as tunable precursors for polymeric pigments. In these structures, phenols are presented in a (supra-)molecular context dictated by the positions of the amino acids in the peptide sequence. Oxidative polymerization can be tuned in a sequence-dependent manner, resulting in peptide sequence–encoded properties such as UV absorbance, morphology, coloration, and electrochemical properties over a considerable range.
The happy accident occurred during an attempt to create new materials for use in electronics when a grad student extracted a mix from the furnace and saw a brilliant blue. "You know what Louis Pasteur said?" the professor, Mas Subramanian, recently asked NPR. "Luck favors the alert mind." The group was lucky indeed, because the blue is the first to be discovered in two centuries. The team named the blue YInMn for the elements it comprises--yttrium, indium and manganese--and it has just become commercially available as paint via the Ohio-based Shepherd Color Company, reports Quartz.
Metals left behind in dinosaur fossils might offer a clue to what colors graced their feathers. Scientists have used x-rays to map the copper, zinc and calcium in feathers from living birds. These metals revealed where the birds were marked with different forms of melanin pigment, the team reported September 23 in the journal Scientific Reports. "This work on modern animals now provides another chemical'key' for helping us to accurately reconstruct the appearance of long extinct animals," coauthor Roy Wogelius, of the University of Manchester in England, said in a statement. Melanin is the dominant pigment in birds and other mammals, and colors our skin, eyes and hair.
From the vivid plumage of the cardinal bird to the beaks of the zebra finch, the colour red is an alluring signal for many birds as they attempt to attract a mate. Now researchers have discovered what it is that allows birds to produce their striking red colourings. For the first time, they have identified the genes that allow certain bird species to produce the bright red pigment that plays such an important role in their romantic entanglements. The findings, outlined in two new studies published in the journal Current Biology, could help explain why the striking markings seen in male birds are so attractive to the often dowdy opposite sex. 'Nobody knows for sure why red color is associated with reproductive success,' said Joseph Corbo from the University of Washington, who worked on one of the studies.
A pair of scientific papers has identified the same single gene as the source of red colouring in birds. The gene makes an enzyme that lets the birds convert yellow pigments, which they eat, into red ones, which are deposited in their feathers or beaks. Two separate teams made the discovery, using both traditional genetic "mapping" and whole-genome sequencing. One focussed on the zebra finch, which can have a red or yellow beak; the other on red canaries. Both studies are published in the journal Current Biology.