Origins of life in Newcastle

ICaMB’s Prof Jeff Errington organised and hosted an impromptu symposium on the origins of life at the Centre for Bacterial Cell Biology (CBCB) on Wednesday 18th January 2017. About 80 people attended, hearing 11 talks from a mixture of Newcastle and international speakers, including a number of guests who had travelled over from Japan for the meeting. The program was arranged more or less in “chronological” order, starting with the origins of the solar system 4-6 billion years ago, and ending (still almost 2 billion years in the past) with the emergence of the eukaryotes. The meeting sparked several very lively discussions, perhaps reflecting the difficulty of doing standard hypothetico-deductive experiments on the topic, in the absence of time travel technology! Nevertheless, the day was a great success and is likely to lead to new international collaborations and funding opportunities.

By Jeff Errington

My emerging interest in the subject has two origins. First, through ageing and trying to find a reason for existence before existence disappears! Second, the lab’s work on L-form bacteria (see Box), which has attracted much interest from the origins of life scientific community.

L-form bacteria use a seemingly primitve mechanism of replication.

L-form bacteria use a seemingly primitive mechanism of replication. L-forms are cell wall deficient bacteria, which turn out to replicate by a slightly bizarre, seemingly haphazard mechanism involving membrane blebbing and tubulation. The process provides a model for how primitive life may have proliferated billions of years ago, before the invention of the cell wall.

 

The latest findings have led to a number of fascinating new scientific contacts, and about a year ago, Prof Shige Maruyama, who heads a major Japanese research institute dedicated to origins of life work called the Earth-Life Science Institute (ELSI), made contact, proposing discussion around possible collaborations. After a series of small meetings in Newcastle and my visit to Tokyo, momentum began to emerge, culminating with the proposal for a major workshop in Newcastle, with half a dozen or so ELSI members planning to attend.

Prof Shige Maruyama, ELSI, Tokyo, Japan

Prof Shige Maruyama, ELSI, Tokyo, Japan

As discussions developed, I identified various experts in Newcastle with complementary expertise and interests in the general area, and the idea for a full blown symposium took shape. There was even time to identify a top class international “guest” speaker, Prof Bill Martin from Dusseldorf, who came over at short notice to give the concluding talk.

This is not the place to go through each talk in detail. However, from my perspective, what I hope people took away from the meeting would have included the following general points.

First, the problem is amazingly multidisciplinary, with important contributions from astrophysicists, geochemists, organic chemists, microbiologists (structure/function, metabolism and physiology) and evolutionary bioinformaticians. Second, we still have a very hazy understanding of many of the early events in the earth’s planetary history, e.g. when did the water arrive and how much? Third, it is clear that microbes were responsible for huge changes in planetary chemistry, particularly oxygenation but also that planetary composition must have reciprocally influenced microbial evolution.

Prof Bill Martin, Dusseldorf, Germany

Prof Bill Martin, Dusseldorf, Germany

The day concluded with a very nice dinner at the Jesmond Dene House Hotel, supported by Newcastle University and hosted by Pro-Vice Chancellor Prof Nick Wright. I’m sure that the original owner of the house, Lord Armstrong, would have approved of the day (for example, I gather that his company won the contract to build ships for the Japanese Navy 120 or so years ago). I’m also sure that as a Fellow of the Royal Society (elected in 1843) he would have been acquainted with Charles Darwin and perhaps they too had interesting conversations about the origins of life in their own time frame.

Bulging bacteria and the origins of life

Jeff (left), Romain (centre) and Yoshikazu (right), the team of researchers behind these exciting discoveries

 

In a paper published this week in CellJeff Errington’s team in ICaMB, have discovered new insights into the origin of life on Earth.

 

Jeff and his team share their results

Bacteria were the first organisms to appear on planet earth. Almost all modern bacteria have a tough protective shell called a cell wall. The structure of the wall and the mechanisms used by cells to manufacture it are conserved, suggesting that the wall was invented right at the beginning of bacterial evolution, and, therefore, when the first true cells emerged.

Production of cell wall is carefully regulated by complex machineries that allow the cell to enlarge and then divide in a controlled manner, all the time maintaining the integrity of the wall intact.

Despite its importance, it seems that many modern bacteria can survive cell wall loss under certain very special conditions, such as when they are treated with certain antibiotics that interfere with its production, like penicillin. Not only that, but a few years ago my lab showed that these “L-form” cells (named after the Lister Institute in London where they were first described) no longer need the complex mechanisms normally needed for bacterial growth and division. Instead, they grow by extrusion of irregular tubes or blebs of cytoplasm, that pinch off into daughter cells.

Our team – me, Yoshikazu KawaiRomain Mercier – has been working on this problem for some time. “Studying L-form biology is a real technical challenge, and this work could not have succeeded without the strong collaboration established between us“, says Romain. As Yoshikazu explains: “we developed a very simple genetic system to isolate mutations enabling L-form development from non-viable protoplasts.

We are excited because we think we have now solved the mystery of how L-forms grow and divide. Our latest results, published in Cell, show that the mechanism is remarkably simple: it requires only that cells make excess amounts of membrane – the thin porous layer that acts as the outer boundary of all cells, including our own.

Increasing the membrane surface area beyond the amount needed to contain the cytoplasm causes the cell to buckle and distort. Eventually, this leads to pinching off of membrane bags that are ill formed but nonetheless viable “baby” cells.

Time-lapse photography representing the division of B. subtilis without cell wall (L-form). The images were obtained using light microscopy. Scale bar: 3 μm

At first, we thought this mechanism was too simple to be true, we changed our minds when we were alerted to amazing experiments being done by several groups working on the origins of life, particularly Jack Szostak at Harvard, Saša Svetina in Ljubljana and Peter Walde in Zurich. These groups have been wondering how primitive cells could have arranged to grow and divide efficiently without spilling all of their contents. They recently found that simple membrane bags, called “vesicles”, can be induced to grow and reproduce into multiple smaller vesicles, in the test tube, just by increasing their surface area.

So, in explaining how the bizarre L-form bacteria manage to survive the loss of their beloved cell wall, we think we may now also have glimpsed how the first primitive cells could have duplicated themselves at the dawn of life on earth.

Jeff Errington 
Director of the Centre for Bacterial Cell Biology

 

Cell paper: http://www.cell.com/abstract/S0092-8674(13)00135-9
Cell website: http://www.cell.com/home see PaperFlick
Newcastle University Press Release:http://www.ncl.ac.uk/press.office/press.release/item/how-did-early-primordial-cells-evolve#.US-chen77jQ

Soapbox Science guest blogpost: http://www.blogs.nature.com/soapboxscience/2013/02/28/social-media-from-an-institutional-perspective-why-are-we-on-there

ICaMB website: http://www.ncl.ac.uk/camb/
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