Type II alveolar pneumocyte here pseudocolored as follows: nucleus, purple; nuclear pores light green; perichromatin granules, violet-red; intracisternal bodies, even in the perinuclear space, light blue (these are looking more and more like they might be over production of Surfactant protein A – a collectin which has modest surfactant properties in the alveolar space but probably greater impact on pulmonary immune function. Interestingly it lines up pretty much on the button with two mirror sets of the actual surfactant protein A molecule (which is a group of 18 similar single protein units spanning about 50 nm, so two top to bottom would be about 100 nm the width of one set of bands in an intracisternal body — at least I hope it works out that way); lamellar bodies, of which there are four, gold; and a single mitochondrion, green.

Still probing the literature to see whether I can match up a protein to the paracrystalline pattern seen in electron micrographs of guinea pig, ferret and sometimes in dog lung, I found a paper which might shed some light on the issue. “Formation of membrane lattice structures and their specific interactions with surfactant protein Nades Palaniyar, Ross A. Ridsdale, Stephen A. Hearn, Fred Possmayer, George Harauz, American Journal of Physiology – Lung Cellular and Molecular Physiology Published 1 April 1999 Vol. 276 no. 4, L642-L649 ” from which I borrowed without permission from the publisher a small portion of one image to compare with a small portion of an image of mine.  Their estimate of the size of the banding pattern at 50 nm in vitro bilayer sheets is very close to my estimate of banding found in vivo, in this case in guinea pig lung, animal M-8041, control, aged, male, I believe.  These are samples from more than 30 years ago, but still represent an enticing visual puzzle.

Here is a short video of the intracisternal protein organization that I have found in guinea pig (and a couple other mammals) in the alveolar type II pneumocytes using transmission electron microscopy.  It seems that in the most advantageous photographs, and with the method of preservation that was used on these tissues (glutaraldehyde – paraformaldehyde fix, with osmium tetroxide post fix, either Epon 812 or Spurr’s resin and lead and uranium staining of the thin sections) show a total of 9 bands (inclusive of side to side) a central more dense band which has on either side each, 3 thin bands.  The central band has a globular look to it, at least in the way these proteins have been fixed with this method.

Here is the video URL:

Three different organizations of this protein, some parallel some perpendicular to the plane of the nuclear envelope.

I continued to be interested in this image of a guinea pig alveolar type Ii cell nucleus, just off to the side which had a couple areas that looked for all the world as if they were part of some coiling of (coiling of the 30 nm coil) and maybe even linked together in a similar fasion as the nucleosomes themselves, but maybe packages of 3 or 4 nucleosomes with a linking region that looked to be consistent as well.   Video is primitive, but it does give relevancy to the big-beads (to be distinguished from the more commonly used “beads” on a string for nucleosomally wound DNA. I really have scoured the internet and science articles to find another who has seen this kind of arrangement of chromatin at the periphery of the nucleus…. I have not found much. Nucleosomes are typically NOT as large as these one-step-further- wound DNA. Video is here:

Here is an awesome picture (diagram) which i found after making my short video…. the link to the diagram and those who made it is here. www.cell.com/molecular-cell/fulltext/S1097-2765%2810%2900172-3