I've always wondered about mesosomes. They were controversial 35 years ago when I was working in a related field. I decided to check the current status of the term.
I checked for research activity in this area using a Web of Science search "mesosome" in Title: this gave just 54 hits. I list the most recent here (unless otherwise indicated, these are single hits per year).
2010; 2008; 2004 (human cell mesosome??); 1994; 1988 (geology); 1983; 1982 (2); 1980
So it doesn't seem to be a very active area of research. The 2008 and 2010 papers are from the same group. The earlier paper is:
Li, X et al. (2008) Mesosome formation is accompanied by hydrogen peroxide accumulation in bacteria during the rifampicin effect. MOLECULAR AND CELLULAR BIOCHEMISTRY 311: 241-247 DOI: 10.1007/s11010-007-9690-4
Abstract: Ultrastructural alteration and hydrogen peroxide localization were examined in Xanthomonas campestris pv. phaseoli during rifampicin effect using transmission electron microscopy. Bacterial cells were treated with rifampicin and then were examined by electron microscopy to observe the changes of ultrastructure or hydrogen peroxide accumulation in living cells that took place before lysis. Intriguingly, rifampicin treatment led to presence of an additional location of hydrogen peroxide accumulation within the cells. There was an association between the frequency and size of the additional location of hydrogen peroxide accumulation and the concentration of rifampicin. Furthermore, an additional ultrastructure, mesosomes, was also present in cells during rifampicin effect. The frequency and size of mesosome increased with the increasing concentration of rifampicin. Result of multiple linear regression showed that the size of mesosome plays as a key factor in the quantity of excess hydrogen peroxide accumulation in cells during rifampicin effect. Linear correlation was confirmed between quantity of excess hydrogen peroxide accumulation and the size of mesosome in cells during rifampicin effect. This finding intensely indicated that mesosomes are just the additional location of hydrogen peroxide accumulation in cells under cellular injury caused by rifampicin treatment. The mesosome formation is always accompanied by excess hydrogen peroxide accumulation in X. campestris pv. phaseoli during rifampicin effect.
This paper has been cited 7 times. One of those citations is from:
Saier, MH. & Bogdanov, V. (2013) Membranous Organelles in Bacteria. JOURNAL OF MOLECULAR MICROBIOLOGY AND BIOTECHNOLOGY 23: 5-12 DOI: 10.1159/000346496
Free full text here.
The language used in this review seems to support the existence of mesosomes as some sort of intermediate in the formation of intracellular membranes in prokaryotes. This review is a polemic in favour of the idea that prokaryotes do indeed contain intracellular membrane-bounded compartments. It has no abstract, but the first paragraph gives a flavour of its stance:
The traditional view of life on Earth divides the living world into two major groups, prokaryotes and eukaryotes. These two groups were originally suggested to differ in very basic respects. While eukaryotes had complex cell structures including a cytoskeleton and intracellular membrane-bounded organelles, prokaryotes were believed to lack them. In fact, numerous textbooks and current sources still note this distinction and hold it to be true. For example, in Campbell’s Biology [Campbell, 1993, p. 515] it is stated without equivocation: ‘Prokaryotic cells lack membrane-enclosed organelles.’ In ‘Functional Anatomy of Prokaryotic and Eukaryotic Cells’ [Tortora et al., 2009, chapt. 4] it is similarly claimed that ‘Prokaryotes lack membrane-enclosed organelles, specialized structures that carry on various activities’. In the current Wikipedia, under ‘Prokaryote’ the following statement can be found: ‘The prokaryotes are a group of organisms whose cells lack a cell nucleus (karyon) or any other membrane-bounded organelles’. In the same online compendium under ‘Organelle’, one can read: ‘whilst prokaryotes do not possess organelles per se, some do contain protein-based microcompartments’. Proteinceous microcompartments will be the subject of a forthcoming Journal of Molecular Microbiology and Biotechnology written symposium, but this one will show that these generalizations, suggesting a lack of subcellular compartmentalization in prokaryotes, are blatantly in error [Murat et al., 2010a].