From the President

The age of the earliest origins of (microbial) life on Earth extend to at least four billion years ago. There is renewed debate on exactly how and when the three major extant groups of life forms on Earth (bacteria, archaea and eukaryotes) evolved and diverged. 

But, whatever the consensus emerges, it is clear that all of life is microbiological in origin and all plants and animals depend on microbial collaborations and endosymbiosis for their existence. This issue celebrates the Archaea – one of the three basic cell types on Earth, and one perhaps that few members of the general public will have ever heard of. 

The late Carl Woese, a pioneer of 16S ribosomal DNA sequencing, was first to recognise the distinction between the Archaea and other prokaryotes, publishing the seminal paper on this topic in 1977. Therefore, Woese revealed a new view of the world showing that the basic arrangement and evolution of life forms on Earth comes from three basic microbial prototypes. This refined and extended the previous paradigm published in 1962 by Roger Stanier and C. B. van Niel who first established the division of prokaryotes and eukaryotes based in part on whether they had a membrane-bound nucleus. Although we have only known of their very existence for less than 40 years, it is clear that the Archaea are an ancient and fascinating independent group of organisms (see in this issue the article by Laura Eme and Thijs Ettema). 

This issue rightly celebrates the Archaea as the least well known of the major divisions of life. We used to think of these organisms as being restricted to the more extreme environments and ecosystems. While it is true that these organisms include notable thermophilic and halotolerant species (see the review on thermophilic archaea by Daniela Barillà), it has turned out that archaea are very much more widely distributed than first thought. The importance of these organisms in many guises is set out in this issue. See, for example, the articles by Graeme Nicol describing the contributions that archaea make to soil nitrification and other aspects of the nitrogen cycle, and to the biodegradation of sewage (article by Marta Filipa Simões and André Antunes). There is also an interesting account of how the CRISPR-Cas system is linked to archaea (article by Qunxin She and Wenyuan Han). Please also read the commentary by James Chong on the apparent absence of pathogenic archaeal species.

I wonder if you read the recent article in Cell Reports by Asuncion Delgado from Jose Sanchez-Ruiz’s lab, who showed that a ‘fossil’ bacterial protein (thioredoxin) could be expressed in a contemporary bacterium (Escherichia coli) and modify its properties. Bacteriophages need to recruit this redox protein for their replication, and what was interesting was that expression of these ancient thioredoxin proteins could, to a greater or lesser extent, render modern E. coli phage-immune. The reason for mentioning this is that the study of ancient microbes, and the understanding of how they evolved into modern ones, might provide novel insights and opportunities to develop desirable properties, such as virus resistance in plants and animals. Archaea are one such group of microbes that have not been fully explored in terms of their ecology and utility.

Elsewhere in this issue you can catch up on Microbiology Society news, with an overview by Laura Crick on conferences and meetings and information about the new Membership Directory from Paul Easton. The Early Career Microbiologists’ Forum is now gearing up and has quickly become integrated into the central machination of the Microbiology Society (see article by Rebecca Hall). There are other Society updates from Benjamin Thompson, and also Hannah Forrest with information on schools activities and the Antibiotics Unearthed project.

Neil Gow

President
[email protected]