Tag: science

Vastly better X-ray crystallography

Free-electron lasers provide femtosecond X-ray pulses with a peak brilliance 10 billion times higher than any previously available X-ray source. such pulses could outrun key damage processes and allow structure determination without the need for crystallization and would be sufficient to image HIV, influenza and herpes, and further improvements may soon allow researchers to tackle the study of single proteins

it would be a huge improvement if you don’t need to grow crystals.

Cold life

fun interdisciplinary work:

Cornell chemical engineers and astronomers offer a template for life that could thrive in a harsh, cold world – specifically Titan, the giant moon of Saturn. Their theorized cell membrane, composed of small organic nitrogen compounds and capable of functioning in liquid methane temperatures of 292 degrees below zero

2022-12-02: The cosmic significance of life on Titan

Saturn’s largest moon, Titan, has a surface temperature of 94 degrees Kelvin above absolute zero, about a third of Earth’s. Titan is located 9.5x farther than the Earth-Sun separation and the surface temperature of Solar system objects declines roughly as the square-root of their distance from the Sun.

Coincidentally, 94 degrees was the temperature of the cosmic microwave background 100ma after the Big Bang when the first generation of stars formed. An object like Titan forming out of gas enriched by heavy elements from the first supernovae, would have had this surface temperature irrespective of its distance from a star. The bath of cosmic radiation would have kept the object warm for 10s of millions of years, sufficiently long for primitive forms of life to emerge on it.

This coincidence of temperatures raises the fascinating possibility of testing how early life could have arisen in the Universe by studying Titan. The question of whether Titan hosts life has cosmic implications. It could unravel the roots of Life in the Cosmos

Parasite rex

If you can overcome the horrors in this book (aliens is nothing), this is very very interesting. It’s likely that most species are parasites, parasites can control speciation, sex, move effortlessly from dinosaurs to mammals when the former die out, etc etc.
2022-12-06: A more nuanced view

“Among all known animals, there are more species that live as parasites than are free-living.” Parasitic life styles exist in all major animal groups, with the single exception of echinoderms, the phylum containing starfish and sea urchins. Parasitism is rife, too, among plants and, as you’d expect, fungi. Many organisms are what are termed “obligate parasites,” unable to complete their life cycle in the absence of a host—and obligate parasites include viruses, which, some scientists contend, aren’t even alive until they hijack a host’s cells.

Among the parasitic infections that affect humans, a large portion are caused by various species of nematodes, a phylum of worms. Nematodes account for 80% of all animal species and are so plentiful that, the authors write, one could “line them up end to end and have nematodes in every meter across our entire galaxy.” Envisioning a “parasite Olympics,” the authors award their gold medal to the nematode Ascaris lumbricoides, which has succeeded in establishing residence in the intestines of 15% of the human population, more than 1b people. The worm causes a tropical disease, ascariasis, whose symptoms include fever, abdominal pain, cough, vomiting, and weight loss. The success of the species comes in part from the fact that, unusually for a parasite, it doesn’t require an intermediate host—the way that malaria, say, needs a mosquito in order to infect a human. Instead, Ascaris is transmitted from person to person via contaminated feces.
Humans appear to have incorporated products of beneficial parasitic infection. The endosymbiosis theory holds that we may have co-opted parasitic bacteria that are now essential to life. Early in the evolution of single-cell organisms, bacterial parasites that were not destructive entered cells. These parasites ultimately became mitochondria, the organelles within the cell which produce energy—a structure essential to animal life.