FOTD #065 : Parrot Waxcap! (gliophorus Psittacinus)

Punctelia reddenda

This gorgeous foliose lichen grows in rosettes up to 6 cm in diameter. The upper surface is gray-green to yellow-green with white, punctiform (point or dot like) pseudocyphella which turn into soralia which produce granular or nodular soredia. The lower surface is black toward the center and lightens to brown near the rounded margins of the overlapping lobes. P. reddenda grows on mossy tree trunks and rock in Africa, Macaronesia, North and South America, and Europe.

images: source | source

info: source | source | source

gorgeous mold in a petri dish, Sporothrix schenckii

this is the content i'm in the microscopy subreddit for

Ode to the Microbe

Prints

I’ve done it! I’ve designed such an incredibly cursed molecule that MolView doesn’t even assign it a systematic IUPAC name. Behold:

The image doesn’t even show up right in the post editor lol. This thing would have such unbelievably ridiculous angle strain that if a molecule of it was ever assembled, it would almost certainly degrade instantly. Possibly violently.

could you explain why/if we can't just copy the genes of one animal and splice them into another animal, for example why we couldn't give humans cat ears?

There's no one easy way to answer this, but the basic answer is that it's not that simple. There's no one gene, or even easily reducible set of genes, that just is "make cat ears". Not only is there a network of genes activated within a cell, there are a myriad of signals from nearby cells (the "microenvironment") as well as cues from the rest of the body and environment.

So each one of the cells making your ear isn't just encoded to be a cell that makes your ear. In fact, most of them don't have any "ear" genetic characteristics or activation. They're generic cartilage or skin cells that were told to grow more or less by neighboring cells or distant cells during carefully coordinated times during growth and development. Each cell interprets this signal in different ways, and also receives multiple signals at a time, the combination of which can produce unique results.

The easiest to interpret example of this is finger development. During development, when your hand is still a fingerless paddle, a single cell on the pinky side of your hand (or thumb side, it could be reversed) releases a signalling molecules to nearby cells. A cell receiving the highest dose will start to become a pinky, and send a signal for the cells immediately around it to aide in that. The next cell that isn't aiding that, but still receives the initial signal, receives a lower concentration of that signal since it's further away. That lower concentration signals a ring finger, and it repeats until you get thumbs at the lowest concentrations.

That's the most visible example, but it's similar to what happens all over the body- signals that are dependent on the structure and genetics of the microenvironment, not just the genetics of the developing cells alone.

This careful network of timing, signals, gene activations, and spatial placement of cells is the core of the field of Developmental Biology (which, technically, my PhD is in as well bc it's often wrapped in with molecular bio lol).

So making cat ears on a human genetically would essentially require not only genetic manipulation, but also babysitting the fetus the entire time and adding in localized signals to the microenvironment of the developing ear cells, which is essentially impossible. There's too much "human" flying around to realistically get that result, and an attempt at doing so would essentially be akin to molecular sculpting. That's why *my* preferred approach would be epithelial stem cell manipulation/printing and subsequent grafting, but that's an entirely different thing.

If you're interested in this kind of thing, the most approachable and engaging summary of developmental biology is the book "Your Inner Fish", by Neil Shubin, the discoverer of Tiktaalik. He summarizes a lot of dev biology through the lens of evolutionary biology, which is a great way to see how differences in structures have arisen and differentiate across the tree of life.

If you want a shorter introduction, and like cute but kinda "cringey in the way you love" science parodies: the song evo-devo by a capella science is really fun and gets stuck in my head a lot:

But yeah, hope that answered your question!

plants that never ever bloom

little creature of the day: Euglena gracilis

micro organisms time

image source

Yersinia pestis

Yersinia pestis is the bacterium responsible for plague, with the most common manifestations being bubonic plague, septicemic plague, and pneumonic plague.

Image taken via transmission electron microscopy. Bar = 1 μm

Photo credit: Hans R. Gelderblom, Rolf Reissbrodt/RKI