Daily Archives: December 11, 2017

Stub tail monkey liver: desmosomal mitochondrial tethering

This is just a micrograph to justify the idea that the desmosomal mitochondrial tethering, or junction or des-mites as i have aptly named them (as opposed to pore-mites) for nuclear pore mitochondrial tethering, are pretty universal. Here a single tether is in a stub tail monkey hepatocyte, from tissue taken back in the 1970s while studying the effects of infusing artificial blood emulsions (perfluorochemical based blood substitutes) . This particular monkey (Maccaca speciosa, probably female) did receive two test doses of a perfuorodecaline emulsion, just a tiny amount, 0.05cc/kg of a 10% emulsion PP5ct and 5% F68) (Lee Clark Jr named all his emulsions, this was EM#750428). no perfluorochemical droplets were seen in this hepatocyte. Sac date was 5 10 76.

So desmosomal mitochondrial junctions are here. Mitochondrion is in top part of micrograph, desmosome is attached to the down pointing portion.

 

More pseudocolored desmosomes and mitochondria – tethered

Here is another pseudocolored desmosome with portions of two mitochondria top and bottom parts of this electron micrograph. It was difficult to determine exactly where the plasmalemma from each of these two cells went at the point of the desmosome, but I thought long and hard about which part of the structure they were. It seemed to me that there was a slight electron lucency just under the plasmalemma on each side, therefore this is the way I pseudocolored (with pink) the cell membranes.  The densities within the desmosome itself looks like there are three rows… the central dotted (periodic) line where the cadherin molecules knot together (my guess is this is a totally symmetric arrangement, not at all random like suggested by some) and perhaps another periodicity (well not perhaps…. it is pretty striking) which lies a little separated from the plasmalemma.  I don’t know if any of the models of the cadherins show a “lump” structure before the transmembrane part… ? That will take some searching.

Top image is unretouched transmission electron micrograph of a desmosome, as mentioned, mitochondria portion seen top and bottom.  The box in this image is what is enlarged in the second image. There are two very prominent intramitochondrial granules, especially the one in the mitochondria at the bottom of the micrograph.
This image is from the boxed area above, thus enlarged, pink is the plasmalemma, orange is the area just under the plasmalemma of each cell and into the space of the desmosome. Blue is what I see as the possible densities of cadherin molecules.

In this inset the periodicity of the outer part of the desmosome (probably still cadherin molecules) is a spacing about 1/15nm  not too different from that found in a previous post at something around 1 density for each 13-14nm spacing.  The periodicities on the central dense line of the desmosome in this micrograph might be something around 18nm spacing… I would have preferred if the densities came out one-to-one, but anticipate that in other assessments that it might do just that. But for now, i just count what shows up. 6102_5070_mouse_female_control.

FROZEN? in more ways than one

First the apologetic! Few grew up in an atmosphere more infused with Disney than I did. Southern california born – a father who lived on Mariposa next door to July Garland – steeped in Hollywood culture from afar – a cartoonist in high school – a short-time employee of Disney studios as an “in-between” man (i think my dad wanted more freedom). My aunt Joyce Weil lived next door to Ollie Johnson, long time Disney employee and toy train addict, upon whose backyard miniature steamer?  train I rode as a child – my best friend’s mother painted all the skirts of the fairies (dandelion seeds) in Fantasia – our summer vacations were at Disneyland… my favorite place on earth – and my sister was a cast character at Disneyland for a while – my brother worked marionettes for a disney film – and from time as a toddler to teen years I dreamed of working at disneyland painting the pretty parts of Fantasyland.  My mind is still full of gingerbread-type ideas. I have made stained glass disney panels for the woman who was the original Mickey, and is still Minnie at disneyland and did Pete’s Dragon for one of the lighting engineers. There have been countless family gatherings under the disneyland christmas tree – though now a gathering would be without those who have departed from our presence, but would be filled with new little faces. Basically I wanted to live at Disneyland. I am, because of this upbringing (or at least modified by it) an incurable romantic, waiting still for a prince charming to find me, and to live happily ever after in a fairy-like castle.

The impact of fantasy – on our lives, and perception of life? How good is it, how damaging. I wont weep that my dreams were never fulfilled…. or even suggest that at a wise and sage 74 and having been a scientist for 40 years that that might qualify me to be a consultant on their “imaginarium” team, for biology, histology, and physiology which I would do for free… This wont happen either.

What i will comment on is the impact of that environment had on an already slightly “fantastical” (haha) mind. I wept watching the TV version of Frozen last night. In some way it touched me really deeply, because 1) of the sister thing and the separation (in distance) between me and my two sisters, 2) because of the struggle to understand that ultimately “love” conquers all and 3) because in some ways a profession (mine in science) reinforced the separation that i feel from the fantasy/love/happily ever after part of my brain which I had hoped would be the main path of my life.

My prayers to all of you who have not yet found the “anna” in your hearts, but are like “elsa”- afraid, reserved, frozen.  I don’t know if i would have ever found the “anna” in my own life had i worked in the field that i dreamed of as a child…  maybe, maybe not, I pass no judgement on the impact of fantasy on the reality we all must live with, especially the impact on the young, and young at heart. Reality ≠ Fantasy = Disney.