From the President

When I was first a student of microbiology, this field was introduced to me as the biology of ‘invisible organisms’ – i.e. the study of microbes, which are below the resolution of the human eye. Strictly speaking that definition has never really been accurate, but it is true that the science of microbiology was born when Antonie van Leeuwenhoek made a first microscope capable of resolving bacteria, and it has progressed in no small measure by generations of inventions that expanded the ways in which we can image microbial cells. This issue is devoted to the science of imaging.

In my office I have a golden mu (µ) symbol, which I used use in teaching our Access course to symbolise the scale for microbiology – thousandths of a millimetre. As a very crude rule of thumb, and with exceptions, I will tell students taking their first class of microbiology that viruses are on the sub-micron scale, bacteria have a diameter of around a micron, and eukaryotic microbes are often around 10 microns in diameter. It is claimed that the most acute human eyes can resolve about 576 megapixels and, at best, see something as small as 20 µm in diameter. Mine can’t! However you estimate the performance of the eye as a lens, microbiologists need microscopes.

The advances in imaging technologies in the last decades have been astonishing. Coupled with the creation of fluorescent proteins, dyes, antibodies and other ways of labelling individual components of the cell, we can now see microbes like never before. The repertoire of imaging technologies that are now available allow us to bridge the scales of life, from the molecular to the cellular to the colonial. We can watch cells grow and divide, respond to stimuli, or die in response to an antibiotic or the expression of a conditional mutation. From the human end of a lens we can now drill down to observe, in real time, the molecular events that drive the metabolism, growth, movement, behaviour, multiplication and cell division of viruses and cellular microbes. In this issue you will find fascinating articles that introduce technologies such as high containment microscopy, single molecule localisation microscopy, fluorescence in situ hybridisation (FISH), Mesolens, cryogenic soft X-ray tomography and single-cell time-lapse microscopy. 

It is not only light microscopes that have been revolutionised. Since the electron microscopes first resolved the fine structure of tobacco mosaic virus, ultrastructural imaging has also undergone a constant series of advances. We can now use high pressure freezing to instantly immobilise microbes to generate superb representations of fragile and intricate subcellular structures. Tomography can be used to render 3D images of nanometre scale features of the cell, and cryo-electron microscopy is complementing X-ray crystallography to enable detailed models of the molecular machines of life to be resolved. The area of imaging has therefore been one of sustained interdisciplinary invention – on par with the extraordinary advances in DNA sequencing and other -omic technologies. As microbiologists, limited by the resolving power of images that fall on the human retina, we have benefited more than most from these technologies, and, indeed, since necessity is the mother of invention, microbiologists have contributed significantly to the set of imaging technological revolutions. I hope you will enjoy this issue.

It is now the start of 2018 – and 2017 was a good one for the Society – with a new Strategic Plan in place to guide the way forward. I think we have gone a long way to showing that we can be bigger and also better, wider in our vision, but not forgetting and passionately empowering our members individually. 2018 will prove to be yet another step forward for you and for us.

Neil Gow

President
[email protected]