I'm reading Biochemistry - 4th edition - Voet and Voet.

 

It says this:

 

 

Although prokaryotes
lack the membranous subcellular organelles characteristic
of eukaryotes (Section 1-2), their plasma membranes may
be infolded to form multilayered structures known as
mesosomes. The mesosomes are thought to serve as the
site of DNA replication and other specialized enzymatic
reactions.

 

Uhhhhhh....

 

I thought mesosomes were artifacts... Are they not?

Something change in the realm of biology in the past couple of years?

That has been under discussion on and off and certain EM people do not like the idea of artifacts within biological samples (although they are copious). In more recent times (sometime after 2005, I believe) people have more accepted that mesosomes are not pure artifacts per se, but rather a physical manifestation of certain damages to membranes, which can happen under a variety of conditions. So on EM they are the result of artifacts, but these ultrastructural changes also happen in vivo (though often accompanied by cell death), but are certainly not organelles as created by the organism.

It was not that big of a contention for microbiologists anyway and biochemist tend to lag behind these areas for a few years. Considering the significance (or lack thereof), the time frame and the scope of the book it appears that they just missed it.

Interesting, I was wondering about this when I came across it in many of the recent text books. Still seems like there quite some discussion about this going on.