Monthly Archives: June 2017

Asymmetrical apoptosis with four blips

Nuclear pores and nuclear architecture, Nuclear symmetry during apoptosis, Nucleoar organization, Ultimate order, the cell

I ask forbearance for my posting this. I have seen this asymmetrical type of apoptosis in some experiments that were done while investigating an anti-apoptotic gene. I was just doing the electron microscopy, others were doing the cell culture and knockdown experiments.  Typically apoptosis in culture presents with a round nucleus lots of large nucleoli and a bilateral (mostly) distribution of granular material along the inner nuclear membrane of the cell as it dismantles itself. The squeezing and pinching in this type of apoptotic cell was just really unusual and as is always the case on government grants, the reasons were never flushed out because of time and money constraints.unusual apoptosis in knockdown tissue culture experiment A549 cells I bet there is a really interesting reason for these, and this particular set of culture dishes got a scrambled version of an si67 probe and was supposed to be a control. It seems to me that part of the nucleus a just got extruded? I did count 8 nuclear pores (main criterion being an obvious set of cytoplasmic filaments off the cytoplasmic side of the pore.  Few mitochondria, many vesicles. One interesting thing about this apoptotic style is that the cytoplasm is not full of ribosomes as occurs in apoptosis in many cell types.

It is not something i could have made up (LOL) but my initial guess is that the four little ball-antennae are some remains of cajal bodies, and heretically i could suggest that the linear divisions radiating out into the “skirt” of whats left of the nucleus, likely has something important to do with each chromosomal territory (separations, walls, scaffolding, call it what you like).

 

Electron micrograph of an hepatocyte (gd 20 fetal liver)

Electron micrographs of liver, Environment and contaminants, The cell: images, Ultimate order, the cell

From a study in the 1980s looking at exposure of pregnant dams to CO or dichloromethane by inhalation, here is a kind of “pristine” hepatocyte from ad gd 20 fetal rat. The nuclear pores are numerous but not really that distinct, and the RER is nice and flat but also has a dense content, and the mitochondria have cristi that are not completely flattened and there is not a lot of it, and very little SER that I can find and this cell is adjacent to two hematopoietic cells, no desmosomes between. M=mitochondrion, C=cytoploasmic side, N=nucleoplasmic side arrows point to condensed (closed) and euchromatin (open). Ribosome can generate a relative size comparison for other structures, being about 27 nm in diameter (red dots), the nuclear fibrils just at the nuclear pore (almost dead center in the micrograph and within the black dotted lines) about 30 nm (black) and perichromatin granule in purple. The project, as I recall, did not uncover any differences between the exposed and non exposed animals, and in this case, the hepatocyte looks nice.