Tiny crystals give a plain fish twinkling, colorful dots under light

 

This article talks about the discovery of blue and yellow flashing dots on the silver slips of fish when in the light. Masakazu Iwasaka, an engineer at Hiroshima University mentions that instead of making their own light, the fish possess little photonic crystals that reflect certain wavelengths of light. These wavelengths alternate between blue and yellow. The dots were found to be no larger than 7 to 10 micrometers and were splayed out across the fishes back. Scientists went and took a closer look inside the dots and and saw that little platelets of the compound guanine have grown there.

Guanine is one of the major four coding units involving DNA. Iwasaka suspected that the blue and yellows colors only show in living silversides while dead silversides just show white. It was also speculated that the fish use the reflectivity as a type of camouflage or as a distraction from predators. Lastly, the article mentioned how Iwasaka hopes to create human made counterparts to the fishes reflectors and how he has come up with the idea of mimicking fishy structures for sensors.

I think Iwasakas idea of mimicking fishy structure for sensor is a good idea. I would like to see his idea come to life and see how well it works with these fish. I also am fascinated how these fish posses guanine which allows them to display these wavelengths when in direct light. I hope more studies are done to see if other animals have the same ability. Below I have attached another article that talks more in depth about silversides and their dots.

Links:

 https://www.sciencenews.org/article/hardyhead-silverside-fish-crystals-colorful-dots

https://royalsocietypublishing.org/doi/10.1098/rsos.201578

Cancer mutation patters differ in smokers/non-smokers

An international team of researchers found several differences in the amount of altered DNA signatures in the tumors of smokers compared with those from non-smokers with the same type of cancer.

"Tobacco smoking leaves permanent mutations - it erodes the genetic material of most cells in your body", says Ludmil Alexandrov of Los Alamos National Laboratory in New Mexico, who led the analysis. "Even if you are just a social smoker who occasionally has one or two or five cigarettes, there is a cumulative effect."

The team compiled data on over 5000 human samples of 17 different cancers. The DNA was then searched for patterns of damage, known as "mutation signatures". One type of mutation, called "Signature 4", which indicates damage to Guanine, showed a far greater presence in tissues exposed to tobacco smoke. Signature 4 also strongly correlated with lung squamous cancer, lung adenocarcinoma and larynx cancers.

Strangely, signature 4 showed a significantly lesser correlation with oral, pharynx, and esophagus cancer, despite being just as exposed to tobacco smoke as the lungs and larynx. Researchers also were able to graph the relationship between quantity smoked and number of mutations. For instance, a pack a day for one year leads to 150 mutations in a lung cell, 97 in a larynx cell, 39 in the pharynx, 23 in the oral cavity, 18 in the bladder and 6 in the liver cell.

I take interest in the genetic or hereditary aspects of tobacco resistance. I have known individuals who have smoked a pack or so a day for numerous decades and never got lung cancer, and others who have smoked far less over a shorter period of time, yet fell ill with some respiratory related cancer.