The less I know

Come look she said, and introduced me to Trametes versicolor.  Its color pattern so closely resembles that of its distant relation that the fungus is known by the common name, Turkey Tail.


What struck me when I first looked at Trametes was its color and, as I prepared the image to post here, I was again struck by its shades of azure blue. As best as I can determine, blue color, among the basidiomycete fungi, is caused by thelephoric acid, a pigment which belongs to a chemical family called the terphenylquinones.

The color blue is common in plants and, in that group, is caused by a family of pigments called the anthocyanins.


And, what of the color blue among the animals? Certainly we all have our favorite example, and mine is the Blue Bird. I am fascinated by the fact that although the color blue is found among the animals, blue pigment is not. So, this begs the question, how can animals be blue in the absence of blue (pigment)? The answer is found in what is called Structural Color, a phenomenon in which arrays of surface nanostructures scatter light and then reflect particular wavelengths to be seen by you and me. Transparent nanostructures may be found on the wings of some butterflies. These scatter light in a way that reflects just blue wavelengths. While such structures among insects are made of chitin, some bird feathers are known to be modified with keratinous barbs that also function to scatter light in a way that makes surfaces on which they are found appear blue.


In an impressive bit of work, engineers constructed tiny capsules, each containing a suspension of small particles in water. Drying the capsules caused the particles to move together. Differences in drying caused differences in the average distance between the particles which resulted in differential light scattering and in different reflected (structural) colors. Here is a photomicrograph of capsules engineered to produce blue, green, and red structural color. [Park, Jin-Gyu, Shin-Hyun Kim, Sofia Magkiriadou, Tae Min Choi, Young-Seok Kim, and Vinothan N. Manoharan, 2014. Full-spectrum photonic pigments with non-iridescent structural colors through colloidal assembly. Angew. Chem. Int. Ed., 53, 2899-2903.]
Permit me to end now with the, only slightly augmented, words of Michael Franti, The more I see (and learn), the less (I realize that) I know. It’s really true.

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