Scientists say most likely number of contactable alien civilisations is 36

Photosynthetic organisms transform light energy into chemical energy – this process is essential as it is placed at the base of the food chain. Life on Earth has gone through different stages, and the biosphere has changed though these stages.  For intelligent life, multicellular organisms with a nervous system are essential (they have a brain), but this took a very long time. To put this in perspective,  early forms of photosynthesis evolved around 3.5 billion year ago, and complex life (animals) evolved around 600 million year ago.  The right conditions for complex life to evolve were possible once we had our modern Earth System – this happened once plankton colonised the oceans around 800-600 million year ago. In my opinion,  getting this stage is the hardest, because you need oceans, photosynthesis and geological processes to producer oxygen and enough bioavailable nitrogen (in addition to sugars produced by the photosynthesis).  If we find these sort of conditions, we can find complex life.  Now to get to intelligent life, we need time which in our planet this took about 500 million years.  

“But, yes if we evolved in this planet, it is possible that intelligent life evolved in another part of the universe,” Sanchez-Baracaldo – Guardian, June 2020

Origin of Life Initiative Talk – Harvard University

The Sweet World of Microbes at the Royal Society

As part of the Discovery Hub within The Royal Society’s Summer Sessions outreach event, all members of the Sanchez-Baracaldo Lab were showcasing the amazing world of microbes through a range of outreach activities. The Royal Society Summer Sessions event is the ideal opportunity for researchers from a wide range of disciplines to engage with the public in the work they do, and helps show the important part science plays in improving our quality of life, through solving some of the pressing issues facing the world today such as food availability, antimicrobial resistance and climate change.

Our lab focuses on cyanobacteria and diatoms, aiming to understand the biogeochemical processes in which they are involved, as well as the evolution of specific features they possess. Examples include showing how specific enzymes may have evolved, or how certain bacteria became tolerant to habitats of differing salinity. The answer to these questions involves working with the DNA of these organisms, with techniques such as genome extraction and sequencing, comparative genomics to observe differences in genomes and molecular clocks to estimate the geological time period over which bacterial traits arose.

Our first outreach activity was to show part of the process in DNA replication, members of the public could try their hand at being DNA Polymerase through the videogame “DNA PolymeRACE” where players must match DNA bases together, with speed and accuracy being key in achieving a high score.

Visitors were also shown how easy it can be to make models of DNA using only sweets! With strawberry laces for the sugar-phosphate backbone and four different coloured jelly-babies to represent the four DNA nucleobases Thymine, Adenine, Guanine and Cytosine.

The lab also brought along some examples of our current Cyanobacteria and Diatom cultures, along with photographs to demonstrate the diverse range of morphologies. Examples of the lab cultures were also brought along fixed to microscope slides, so guests could get a detailed view of the cells the lab group work with.

Finally, to demonstrate the unique habitat of frozen sea ice, example blocks of sea ice and freshwater ice were brought along. Using yellow dye guests could see how sea ice provides a unique habitat for ice dwelling microbes such as bacteria and diatoms. This is due to how sea ice features numerous small spaces for these organisms to grow in comparison to freshwater ice, giving an insight into the earth’s polar regions.

Outreach events such as this are the perfect opportunity to showcase the science our lab undertakes as well as the big questions we wish to tackle. It’s also a great chance for us to see the other exciting work researchers within the Royal Society are carrying out.

11th Annual Natural Systems and Processes Poster Session (NSPPS)

On the 8^th of April Sanchez-Baracaldo Lab PhD students Giorgio, Elliot and Dan brought their research to the 11^th Annual Natural Systems and Processes Poster Session. NSPPS is a great interdisciplinary opportunity where research groups from across the University of Bristol can showcase their current work to one another, encouraging discussion and collaboration in a friendly and informal setting. Giorgio presented his current work on the evolution of salt tolerance amongst cyanobacteria, Elliot presented his research into nitrogen assimilation pathways amongst Picocyanobacteria within different habitats, and Dan presented his work on the evolutionary history of symbiosis between oligotrophic Diatoms and Nitrogen fixing cyanobacteria. NSPPS was an example of the scope of research carried out by MRes and PhD researchers within the university, other poster examples included Glacial Modelling, Mental Health and examples of UK wildlife such as Bee and Bat species.

New Strains Arrive from Culture Collection Yerseke

Sixteen new strains of cyanobacteria have arrived at the Bristol School of Life Sciences this week from Culture Collection Yerseke in the Netherlands. They comprise a wide variety of cyanobacteria including Spirulina, Cyanothece and Pseudanabaena sp . from freshwater and marine habitats across the globe. For example, coastal regions of Portugal, New Caledonia and Australia.

These strains are currently being kept in culture and soon their DNA will be extracted, and their genomes sequenced for the first time by PhD students Joanne Boden, Dan MacRae and Elliot Druce. The purpose of this work is to gain a better understanding of the phylogeny of these strains, and how they relate to other types of cyanobacteria. As well as this, sequencing their genomes will provide a highly resolute picture of which specific genes each strain possesses, and give a much clearer understanding of what functions they may or may not be capable of undertaking in their respective environment. Cyanobacteria are one of the most diverse taxa across the globe, it is therefore vital to understand their roles and the ecosystem functions each strain provides.

Nitrogen fixing microbes in the Arctic

Maisie Nash

Following glacier retreat, soils are exposed which have been locked under ice for thousands of years. These soils have a low nutrient content and pose an opportunity to study how life first colonizes in extreme environments. Nitrogen fixing microbes (diazotrophs) are crucial for converting atmospheric nitrogen into ammonium, a form which can be used by heterotrophic microbes and plants. This process is important in Arctic soils for building up bioavailable nitrogen, facilitating soil development and further microbial/plant colonization.

In this publication we investigate the diversity of diazotrophic bacteria across four Arctic glacier forefields, using 72 assembled metagenomes. The research shows a core group of bacteria, consistent across the forefields. This may be related to environmental selection, by factors such as cold, oligotrophy and high UV. The article can be found here:

https://academic.oup.com/femsec/article/94/9/fiy114/5036517

Evolution of Superoxide Dismutase Enzymes

Joanne Boden

Oxidative stress damages proteins and DNA and is particularly prevalent in intense sunlight. To combat it, cyanobacteria – like many living things including animals, plants and fungi – make enzymes called superoxide dismutases. At the heart of each is a rare transition metal, such as iron, nickel, manganese or copper which helps to degrade superoxide free radicals before they cause harm. Here in the Sanchez-Baracaldo lab, Joanne Boden is using genetic techniques to investigate whether species living in the ocean use different metals to protect against oxidative stress compared to those living on land or in freshwater. In order to do this, she is searching for genes encoding each isoform in hundreds of bacterial genomes to provide the first comprehensive review of their distribution in cyanobacteria. She is also using Bayesian molecular clocks to simulate how NiSOD diversified during periods of global change recorded in geological records from the Archaean and Neoproterozoic (before dinosaurs and large animals roamed the planet). Overall, this project will help us understand how seawater chemistry effects protein evolution.

Images illustrating the shape of each superoxide dismutase (courtesy of Miller et al 2012), alongside exemplary amino acid sequences used for genome searching.

 

 

The origin of the chloroplast

One of the most recent of our studies  has shed new light on the origin, timing and habitat in which the chloroplast first evolved. The Earth’s biosphere is fuelled by photosynthesis. During this fundamental process algae and plants capture sunlight and transform carbon dioxide into carbohydrates, splitting water and releasing oxygen.  Photosynthesis takes place in green specialised subunits within a cell known as chloroplasts. Scientists have known that algae and land plants evolved after a more complex organism with a nucleus known as eukaryotes; an ancient eukaryote swallowed a cyanobacterium.  While, it is accepted that cyanobacteria, are the ancestors of the chloroplast, it is unclear which of the cyanobacteria are closest related to the chloroplast, when this association first appeared in geological terms, and in which type of habitat this association first took place.

This new study shows that the chloroplast lineage split from their closest cyanobacterial  ancestor more than 2.1 billion years ago in low salinity environments. It took another 200 million years for the chloroplast and the eukaryotic host to be intimately associated into a symbiotic relationship.  This evolutionary study also revealed that marine algae groups diversified much later on at around 800 – 750 million years ago.

Publication:  ‘Early photosynthetic eukaryotes inhabited low salinity habitats’ by P. Sánchez-Baracaldo. J. Raven, D. Pisani and A. Knoll in PNAS  – http://www.pnas.org/cgi/doi/10.1073/pnas.1620089114

Data is beautiful: outstanding data visualisations recognised at University Research Institute event

Nathan’s gets top price for figure published in our paper ‘Tracing cyanobacteria’s tree of life in Earth’s extreme environments‘

New genome reveals how Artic microbes survive in cold extreme habitats

We have sequenced the genome of Phormidesmis priestleyi, in the Greenland ice sheet, they help to form cryoconite holes – dark, dust-filled puddles on the ice sheet surface. Cryoconite holes can be found covering vast areas of ice, making these microbes important ecosystem engineers on glaciers and ice sheets. Phormidesmis priestleyi mainly survives in cold environments by producing extracellular polymeric substances.

Press release is found at http://www.bristol.ac.uk/news/2016/august/arctic-genome.html

Title: Genomic mechanisms for cold tolerance and production of exopolysaccharides in the Arctic cyanobacterium Phormidesmis priestleyi BC1401. 17:533 (2016) DOI: 10.1186/s12864-016-2846-4