|Turned up to eleven: Fair and Balanced|
Sunday, February 10, 2002
Prof this morning, and I think my reply to him was a little confusing, so I will expand a bit here. He cited an article on the whether nanobacteria cause diseases that have been previously not thought to be infectious (ex. Alzheimers, arthritis, heart disease). I made the following points in my e-mail. The first is that this publication appears to be some sort of venture cap newsletter, not a journal of any kind. The article in question was an interview with the doctor (don't remember his name) who runs a company that is claiming to have figured out a way to treat people for these supposed nanobacterial infections. The evidence for the existence is sketchy at best. A group in Finland has been able to use electron microscopy to make images of what it claims are nanobacteria. Other scientists have questioned their method, citing the frequent artifacts present in scanning electron micrograph preparation (the process involves coating the sample with electron dense material such as osmium tetrachloride, and/or freeze fracture preparation to look inside a tissue sample). They have also cited DNA evidence, identifying a new organism in the blood of patients. However, they have not been able to culture these "bacteria". It may well be that the DNA samples are not from a nanobacterium at all, but rather either a previously unidentified bacterium that can live in tissue or blood (not nec. smaller than usual), or some sort of endospore of a bacterium previously identified but not sequenced. An endospore is a form that bacteria take when they want to survive in a very harsh environment, but not reproduce (Anthrax does this, for example). There is in fact a known bacterium, Chlamydia pneumoniae, that forms a quiescent (that is, non-reproducing) morphotype in the blood. This organism has been implicated in cardiovascular disease, but the link is not proven. Paul Ewald, a microbiologist at U. of Amherst, has been a strong proponent of infectious disease etiology for cardiovascular disease in particular. He is cited in the article in question, although I suspect he is none too pleased about that. In any event, it seems very unlikely that nanobacteria of the size that has been suggested exist. The smallest known bacteria are the Rickettsiae and Chlamydiae, with a diameter of ~0.6-0.8 microns. The putative nanobacteria have a diameter of .1 microns at the most. This means that these putative nanobacteria are, based on the averages of these ranges, 1500 smaller than the smallest bacterium. The most conservative estimate, based on the size differentials above, is 216 times the size. Essentially, these putative nanobacteria are smaller than viruses, and on the "average", smaller than ribosomes. A ribosome is the cellular machine required by all known living things for making protein based on the genetic code.
Does all of this mean that nanobacteria do not exist? Not exactly. It is possible, although in my considered opinion unlikely, that an entirely different type of life exists, that does virtually nothing the same way as we do, or any other living thing. This is, however, a very difficult proposition to demonstrate, and the burden of proof lies squarely on those suggesting the existence of nanobacteria. This particular instance strikes me as pretty likely to be a scam, or at best a very generous reading of the scientific evidence as it stands. By the way, don't bet on any significant breakthroughs coming from the peer-reviewed journal realm. The groups involved mainly publish in very obscure journals, and most people to not put much weight on their studies. Further info on the research in nanobacteria can be found by going to the National Center for Biotechnology Information website, which has a searchable PubMed index that is free to the public.