Category Archives: The cell: images

Mitochondrial inclusion: matrix proteins?

Hunting for an answer to what might be the inclusions seen in mitochondria in my micrographs from Rhesus monkey liver I ran onto this awesome paracrystaline inclusion found in mitochondria in some myopathies. I have searched and really have not found a great micrograph, but several pretty nice ones, and am reproducing what looks like an oligomerization pattern to these inclusions.

1) they don’t appear to be formed in cristi but more in the matrix.
2) it seems like there is a limit to the pattern of oligomers – and a border
3) different micrographs show different orientations of the patterning

Cut and paste portions with reasonable resolution and partial diagram of patterns. It is not really clear from micrographs available that these are matrix or intracristi..but they do seem to have a bounding membrane. Top row of segments look like three layers: row 1 flat; row 2 staggered 45 degree end on, row 3 staggered flat.  Middle row looks much different with less than a 45 degree angle to the middle row, and a longer and shorter component, and for rows 1 and 3, a taper to the “bricks”.  Last picture on the bottom right… different again.

Mitochondrial inclusions

Liver from a rhesus monkey shows some mitochondrial inclusions.I found creatine kinase inclusions – paracrystaline but they appeared to be continuous with cristi membranes, SO MAYBE this (as found by someone else below) is not a perfect match but certainly a better match than a summary of the mtDNA mutations which are even more awesome than the paracrystaline inclusions in the monkey liver here. (anm# 97A mid lob, liver, control biopsy december 1974, negative 5743, block 4360, modified karnovsky’s, Epon 812 – to the best of my knowledge).

I havn’t included all the links, but ONE link i am adding which was an awesome summary of different paracrystaline and concentric cristi arrangements. FIND THAT ARTICLE LINK HERE. Mitochondrial inclusions, in general, would be a great topic for study, relating them to various over production of proteins, oligomerization, and loss of function.

YES: GRAVITY is part of the environment

How awesome is this study?  Ha ha…. having been in environmental research for 4 decades, never once did i consider looking at cells without the affect of gravity, and not to make a really bad pun, the gravity of the loss of gravity. FIND THE ARTICLE HERE. This group presents some great micrographs of the nucleolus….  I cant wait to see if the non-bilateral division of the nucleolus in one of their figures can be expanded to the very definite bilateral organization of the nucleus in general which is seen upon preparation for mitosis.

Perfluorooctylbromide: in rabbit hepatocyte

Rabbit liver, two hepatocytes revealed in this electron micrograph. Three possible, one definite, inclusion left over from the infusion of perfluorocarbon, from my notes it looks like perfluorooctylbromide (19.4%PFOB 5%F68), sacrifice dates show that it was more than one year affter infusion.  The mitochondria are pseudocolored green, the microbody purplish, the PFOB inclusion complete round (the density of PFOB is greater than water, which I surmise is the reason these structural footprints are completely round and empty) and the  very tidy layer of proteins around the perfluorocarbon droplet and bounding membrane are blue.  A small (less than 100nm) droplet is typical for the remnants of infusion of the more desirable perfluoochemical blood substitutes. This particular droplet does not show a “black cap” of enzymes which often accompany the droplets. Nice little desmosome between these cells and a bile canaliculus barely seen on the right hand middle.  Golgi in the lower cell at bottom with another microbody (peroxisome – which i should have colored as well.  My recollection is that infusion of some perfluorocarbons was accompanited by proliferation of peroxisosomess (Neg 5890_block_4783_28000x.

Apoptotic nucleus

I wish i had taken a higher mag picture of this apoptotic nucleus as well as identified the cell type. I do know it is from animal #500 in a study of aged ghkaα-/- mice, this particular KO was 12 months old. It could be a parietal cell since in other image parietal cells are shown to have a “glassy protein” (stains without much texture and eosinophilic with H&E) (just recollection here). The RER is greatly, ribosomes are very closely packed (indicating the production of large amounts of possibly large protein products. Checking the fairly electron lucent contents of the RER there doesn’t seem to be any obvious oligomerization, polymerization or layering of the contents.  The light areas in the perinuclear space and around is dilated RER. It could also be a zymogen secreting cell.
One nuclear pore on the middle left nuclear membrane, and a part of another to the right and above that one. Packed ribosomes are in array on the RER membranes (the black and white cytoplasm pictured around the nucleus),  lots of condensed chromatin (purple) which may be exaggerated by the section being somewhat tangential to the widest diameter of the nucleus, and adjacent euchromatin (gold) which in this case looks pretty dark (not just because i pseudocolored it).  There is a prominent perichromatin granule just to the lower right of center (black) and interchromatin group (sometimes called nuclear speckles which to me makes no sense) is light violet.  Pinkish spot in the interchromatin granule  is probably just euchromatin?

Annulus around desmosome – freeze fracture

Here is an image from a letter to the editor (which i didn’t read thoroughly but was just looking closely at the freeze fracture of tight junction encircling a desmosome) and saw what I had seen in the transmission micrographs of thin sections: that is…. a small ring around the desmosome which i called the annulus which is restrictive and different than the intercellular space nearby.   This particular freeze fracture micrograph (original found here)  by Yasuo Kitajima shows it clearly, yet is it not marked. I don’t know what the function is but clearly a “no fly zone” surrounds the desmosome. Top micrograph untouched, bottom micrograph with bar marker and blue dotted lines showing part of the annulus. It is kind of nice that this particular desmosome is approximately what the literature suggests in terms of number of nm for the diameter.


so, next question is what are the semiregularly raised areas…?

 

Weibel-Palade bodies: fun stuff

I have seen these… at the present moment I am looking over the published literature for Weibel Palade bodies (WPD) in order to determine if there is ever a place where ribosomes are present on the bounding membrane.  So far, none. This makes this cell adjesion group of molecules, while oligomerized into very beautiful structures, some like tubules, they are quite different from the intracellular granule purported to be a surfactant protein (possible SP-A) found in the cytoplasm of alveolar type II cells in the lungs of some species… which have a very precise localization and number of ribosomes on their limiting membrane (opposite sides of the long dimension of the granule, and approximately 4 ribosomes per 100nm).

 

Weibel-Palade Bodies (WPB) Layered granules in alveolar type II cells
At least 12 different proteins are found in granules Undetermined number of proteins in type II cell granules
Recovered as oligomers in clathrin coated vesicles Recovered, but not recycled or re-internalized as oligomers
Granules as single membrane bound SMOOTH ER Granules as single membrane bound with end to end distribution of ribosomes,
Interacts with cell elements in blood Interacts with fluid elements in alveolar space
Endothelial cell product Epithelial cell product
Interacts with white cells and platelets Interacts with alveolar macrophages
VWP apparently oligomerizes to influence the shame of WPBs Oligomerization of the SPs involved in intracisternal bodes of alveolar type II cells create the granuel shape
 WPBs maybe storage (albeit a small percent of total) for VWP Granules in type II cells maybe for surfactant protein storage
WPBs have P-selectin in small quantitites, i wonder if these are for binding of clathrin proteins to initiate recycling from the secretion bubble structures after exocytosis of VWP? Re-uptake, recycling of surfactant proteins is not so obvious (but happens) not big obvious vesicles…  at least not that I have seen.

The cell: a polymer chemists playground

I think it is just overwhelming to see the order “of life”.  Starting out with a search for patterns in electron microscopy for desmosomes has led me to find cell adhesion molecules a really fascinating, perhaps the ultimate, cell-environment interface. So I will go on a hunt, just for the pure joy of finding them.

Von Willebrand Factor (article) bar=10nm. “This factor serves as a docking station or molecular bus to which numerous proteins bind during the formation of blood clots.” (quote from article linked above by Zongchao Jia).

NICE Review of a few cell adhesion molecules

It is worth reading this nice review article which deals with adherens junctions and also some other cell adhesion molecules.

Oda and Takeichi 2011 have this nice electron micrograph or cell-cell adhesion, but it is even more interesting to me that the area described with the confines of their arrows, and the area within their bracket, does not show as distinct an organization as the area inbetween their designated zones… Haha.  see bottom two micrographs, their photo unretouched, and the area where I see amazing order, an area which is very organized.

semicircular arrangement (black lines), likely proteins which attach to whatever membrane proteins the circles are, and then the red lines as some molecule which links the former with some cytoskeletal element.  There is a great microtubule over by their arrows, i don’t know what is under their bracket.

Just a note: it looks like the primitive junctional complexes in drosophila are the result of one-size-fits-all type molecule with little segments snipped out as DE-cadherin has every thing but the kitchen sink there….including laminin, proteolytic, and EGF-like domains.

 

Dental impression alginate

This is just a quick post and may not be relevant to anyone in the cosmos but I had several TEMs of dental alginate (in this case it was Kromopan) that were made when I was trying to figure out a way to quanatify gingival overgrowth in mice.  I am not sure that a way was found but we tested several alginates to see which one gave the best tooth “footprint”, gum, and  bone delineation. This was just a fun gemish.  I dont know if i will spend the time to look up the structure and compare what i saw to what is known about the alginate.  But this is an artsie-craftsie version of the original TEM (lower right). Fixed in buffered aldehydes three days after molding in mouse jaw, and routine processing for TEM. Bar marker=1 micron.