A brand-new Scientific discovery : Two Life-forms merging into one

Dr Mohendra Irengbam *

The dodecahedral coastal coccolithophore Braarudosphaera bigelowii :: Pix - Wikimedia Commons

As I have an interest in biology and physics, it is quite exciting to see a new discovery in these two fields of science. This has happened as I read about a new discovery in plant evolution where two different species of organisms [cells] merged into a new cell part. I am writing about it for the benefit of Joe public who are readers of E-Pao in Manipur.

Far from being a giant eyeroll at the religious and the pious, or weaponizing new scientific discoveries towards secularism, my stint is revelry in the progress of science, and to show how humanity has begun to appreciate the advances of science for its welfare. I am not just being resistant to algorithms.

Somewhere on the shelves in my study is a dog-eared copy of a book by the atheist American philosopher Daniel Dennet, titled Breaking the Spell. Religion is a natural phenomenon (2006). He said, religion is itself a biologically evolved concept, and one that has outlived its usefulness.

Daniel Dennet who died aged 82 on April 19 2024, argued that everything must be understood in terms of natural processes (Evolutionary) and such terms such as 'Intelligence', 'free will', 'consciousness'. 'justice', 'the soul' or the 'self' describe phenomena which can be explained in terms of physical processes and not the exercise of some disembodied or metaphysical power. And how such processes operate, he regarded as an empirical question, to be answered by looking at neuroanatomy – the engineering involved in the brains."

Life, according to him, is a quality that distinguishes matter that has no biological processes, such as signaling and self-sustaining processes. It is defined descriptively by the capacity for homeostasis, organisation, metabolism, growth, adaptation, response to stimuli, and reproduction.

"If we look back in time, we will find that we have begun to unravel the mysteries of nature with vast changes in our intellectual achievements. And we continue to explore. "Each scientific discovery forced a retreat of religion as the ultimate and final authority on all matters with the central tenet of religion that all life forms were created by an intelligent agent, typically a god or gods."

In the holy grail of Consciousness, he argued (1991) that the term merely describes 'disposition to behave' - a person's usual way of feeling ( cf. Author's book Points to Ponder, 2013, pp 294-297) and the idea of the 'self' was nothing more than a "narrative centre of gravity" [an abstract entity]. He insists, and I agree with him, that science can untangle even the knottiest conundrums, including the origin of life, which he asserts that recent "breakthroughs" are helping to solve. The topic of this article is one such breakthrough.

I am especially interested in the origin of life from inorganic matter – from the Primordial soup, which has been demonstrated quite a few years ago when Miller and Urey experimented in 1953, to produce basic organic amino-acids – ingredients of LIFE from a mixture of gases. [cf. Author's book 'Manipuri Musings', Spontaneous Regeneration of life forms, Manipur University (MU) Library].

This very recent observation by a team of scientists led by Tyler Coale– a post-graduate researcher at University of California (UC), Santa Cruz [1] published in two papers in the journal Cell and Science on March 28 2024, that two life-forms have merged into one organism, is such a scientific discovery in the history of evolution.

[1] [for reference here below, there are 9 UC that offer undergraduate and graduate programmes. The one I went to see at Berkeley on the eastern shore of San Francisco Bay, is the biggest with ten campuses. A bit like Manipur University].

This recent discovery is only the third such event in the billions of years of our evolution. The discovery goes on to explain the Darwinian evolution of complex life forms from a unicellular life. It is thought to be a major life event that has likely not occurred for at least one billion years. Evolution is a lengthy process, in terms of billions of years.

In a groundbreaking discovery, these scientists uncovered the first known structure in complex cells that is capable of drawing nitrogen from the atmosphere and converting it into a form that the cell can use.

Coale said the process, which is officially known as primary endosymbiosis, happens when one microbial organism swallows up another, and begins to use it like an internal organ. Their findings are described in two papers recently

This incredibly rare event of primary endosymbiosis was observed in their lab when the merger occurred between a type of abundant marine algae Braarudosphaerae bigelowii which is a potentially large evolutionary streptococcus, gobbled up a cyanobacterium UCYN-A. [Cyanobacterium carries out photosynthesis like plants]. Algae are aquatic photosynthetic, eukaryotic [2] organisms without stems.

[2] Eukaryotes are all living organisms other than bacteria and archaea that contain genetic material of DNA in the form of chromosomes. Archaea is a type of ancient microorganism, intermediate between the bacteria and eukaryote. [cf. Authors books Manipuri Musings, Bacteria, Pathogenic bacteria, a kingdom for bacteria, May 2018, MU Library].

Coal said, "Once merged comfortably, this cyanobacterium will allow the algae to 'fix' nitrogen directly from the air and use it to create more useful compounds. Then it becomes an organelle called Nitroplast. Primary endosymbiosis has only taken place twice during the Earth's 4-billion-year history, and both times have been pretty darn important to evolution."

It is true, the first time was when mitochondria came about, after a bacterium was engulfed by an archaeon [3] 2.2 billion years ago [ cf. Author's book, The Origin of the Meites of Manipur, 2009, pp 71,72. Also, For the Beginning of life on Earth, Dec. 2018, Manipur University Library].
[3] Archaeon (Pl. Archaea)- an ancient cell group intermediate between bacteria and eukaryotes.

Those who remember their biology will know that mitochondria are known as 'the powerhouse of the cell', giving body heat, and all that are essential to giving the complexities of life, which I call the human soul [cf. How Mitochondria (ATP) behave like the human soul. 2008. Manipuri Musings, MU Library].

In this endosymbiosis, the host cell provides the new cell with everything it needs, such as energy and nutrients, so that it soon essentially becomes one with the host. Mitochondria in the human cells are such an organelle [cf. Author's book The origin of the Meiteis of Manipur, 2009, pp 71,72, and Manipuri Musings, Scientific discovery of the elusive human soul as Mitochondria, August 2018, MU Library].

Mitochondrial DNA (mtDNA) is a very useful molecule in the human genome for tracing our ancestral origin as they escape shuffling of genetic material between generations [cf. Author's book Points to Ponder, Mitochondrial DNA, pp 24,31-33, 50, 115, 286, 333-334].

The second time round for endosymbiosis was 1.6 billion years ago, when a cyanobacterium (a cell that uses energy from the sun for photosynthesis) was engulfed by a eukaryotic cell. This organelle became a chloroplast.

The event gave rise to the growth of algae , which in turn gave us land plants. Charophyte algae like the Manipuri Kung are the closest relatives of land plants and encompass the transition from unicellular to simple multicellular organisms.

So, as I understand it, with mitochondria being present both in plants and animals, being the result of primary endosymbiosis, plants do need chloroplasts to convert light energy into chemical energy, and mitochondria consume the chemical energy to produce ATP [Adenosine triphosphate] which provides energy to drive and support many processes in living cells, such as muscle contraction, nerve impulse propagation and others.

These scientists can thus see why it's such a big deal that it is happening again. The gobbled Cyanobacterium will allow the algae to 'fix' nitrogen directly from the air and use it to create more useful compounds. Normally, plants gain their nitrogen through symbiotic relationships with separate bacteria. Scientists assumed this is what the algae was up to, combined with a bacterium called UCYN-A.

It seems the Braarudosphaerae bigelowii and cyanobacterium got a lot closer. New Atlas [4] reports that the size ratio of the algae and UCYN-A is consistent among different related breeds of the algae in a recent study. This indicates linked metabolisms as the growth is controlled by the exchange of nutrients.

[4] New Atlas is a collection of maps, and maps are the tools we use to explore and define new frontiers. That is its mission: to trace the development].

"That is exactly what happens with organelles," said Jonathan Zehr, one of the study's authors. "If you look at the mitochondria and the chloroplast, it's the same thing: they scale with the cell. Further, from the images, generated by soft X-ray tomography performed by Berkeley Lab, Scientists show the algae at different stages of cell division. The UCYN-A, as the nitrogen-fixing entity, now is considered an organelle – a Nitroplast."

Zehr reiterated that "For the first time in at least a billion years, two lifeforms have merged into a single organism. The process, called primary endosymbiosis, has only happened twice in the history of the Earth, with the first-time giving rise to all complex life as we know.

Evolution is quite a wondrous and lengthy process, with some random bursts of activity that are responsible for the diversity of life on our planet today. These can happen on large scales such as with the evolution of more efficient limbs. They also occur at microscopic cellular level, such as when different parts of the cell were first formed.

Now, a team of scientists from CU in Santa Cruz have detected a sign of a major life event that has likely not occurred for at least one billion years. They have observed primary endosymbiosis –two lifeforms merging into one organism. This incredibly rare event occurred between a type of abundant marine algae and a bacterium was observed in a lab setting. For perspective, plants first began to dot our planet the last time this happened."

"It's very rare that organelles arise from these types of things." Tyler Coale, a co-author of the Cell study and a postdoctoral scholar at the University of California, Santa Cruz, said in a statement. The first time we think it happened, it gave rise to all complex life."

Carolyn Larabell, a study co-author and faculty scientist at Berkeley Lab's Biosciences Area, and Director of the National Center for X-Ray Tomography, said in a statement, "We showed with X-ray imaging that the process of replication and division of the algal host and endosymbiont is synchronized, which provided the first strong evidence."

"This system is a new perspective on nitrogen fixation, and it might provide clues into how such an organelle could be engineered into crop plants," said Tyler Coale. Jonathan Zehr, co-author at UC Santa Cruz, said in a statement that "scientists will likely find other organisms that have similar evolutionary stories as UCYN-A, but this discovery is one for the textbooks."

For my money, whether it is a major breakthrough in evolution remains to be seen in the years to come.