Evolution is a very amazing and long process involving several random bursts of activity that is responsible for the diversity of life on Earth today. These can occur on a large scale, such as the evolution of more efficient limbs. They also occur in: microscopic cell levelsuch as when the different parts of the cell were first formed.
Now, a team of scientists has detected signs of a major life event that likely hasn’t happened for at least a billion years.they observed primary endosymbiosis– Two life forms merge into one organism. This incredibly rare phenomenon occurs between an abundant species of marine algae and bacteria, and was observed in a laboratory setting. For reference, the last time this happened, plants started dotting the earth for the first time. The results are described in his two papers recently published in the journal. cell and science.
The “powerhouse of the cell” and where the chloroplasts are located come from
Primary endosymbiosis occurs when: one microorganism engulfs another microorganism. Then, they begin to use the swallowed microorganisms as internal organs. The host provides several benefits to organisms, now called endosymbionts, such as nutrients, energy, and protection. When it can no longer survive on its own, the engulfed endosymbiont becomes an organ of the host called an organelle.
“It’s very rare for organelles to develop from these types of things,” says study co-author Tyler Cole. cell Researcher and Postdoctoral Fellow at the University of California, Santa Cruz stated in a statement. “The first time we think it happened, it gave rise to all the complex life.”
Endosymbiosis, in which a host organism provides the basis for the functioning of another organism, has occurred only three times in known times. All of these individuals were a major advance for evolution, as fusion with the host became the basis for the endosymbiont’s very existence.
The first event occurred about 2.2 billion years ago. This happens when single-celled organisms called archaea swallow bacteria. Eventually it became a mitochondria..what is this special organelle What every biology student learns is the “powerhouse of the cell” And their formation made possible the evolution of complex organisms.
“Everything more complex than a bacterial cell exists because of that event,” Cole says. “About a billion years ago, the same thing happened with chloroplasts, which gave us plants,” Cole said.
This second event occurred when more advanced cells absorbed the cyanobacteria.Cyanobacteria can harvest energy from sunlight, ultimately Cell organelles called chloroplasts Energy can be collected from sunlight. Chloroplasts have given us another core principle of biology.green plants We can make food from the sun.
Along with this Latest endosymbiotic events, the algae may be converting atmospheric nitrogen into ammonia that can be used for other cellular processes. However, we need the help of bacteria.
New organelles?
inside Paper published in cell, A team of scientists shows that this process is happening again.they saw something a species of algae called Braaldosphaera Bigelowi. The algae that swallow the cyanobacteria give them a little plant superpower. Nitrogen can be “fixed” directly from the air and combined with other elements to form more useful compounds. This is something that normal plants cannot do.
Nitrogen is very important nutrients Life exists and plants usually obtain life through interactions with bacteria apart from plants and algae. The team’s first thought was to B. Bigelowi The algae had this kind of symbiotic relationship with a bacterium called UCYN-A. In fact, the relationship became even closer and more serious.
[Related: You have no idea how much you need these bacteria.]
They are, Size ratio of algae and UCYN-A bacteria remains similar between different related species B. Bigelowi algae. Growth appears to be controlled by the exchange of important nutrients, coordination of metabolism. This synchronization of growth rates led the researchers to call UCYN-A organelle-like.
“That’s exactly what’s happening in organelles,” says study co-author Jonathan Zehr, a microbial oceanographer at the University of California, Santa Cruz. stated in a statement. “If you look at mitochondria and chloroplasts, it’s the same thing. They change to suit the cell.”
Introduction to Nitroplast
To look for further evidence that this bacterium is an organelle, we had to look deeper inside.of Research published in journals science We looked inside the living room using advanced X-ray imaging. B. Bigelowi algae cells. This revealed that the replication and cell division of the host algae and UCYN-A bacteria are synchronized. It provided further evidence that the primary endosymbiosis of this organism’s binding process is functioning.
“Until this paper was published, there was some question as to whether this was still an ‘endosymbiont’ or whether it had become a true organelle.” “We’re thrilled to be working with the National Center for X-ray Tomography,” said Carolyn Larabelle, science faculty member and director of the National Center for X-ray Tomography. stated in a statement. “We used X-ray imaging to show that the replication and division processes of host algae and endosymbionts are synchronized, providing the first strong evidence.”
they too We compared proteins from isolated UCYN-A bacteria with proteins inside algae. cell. The researchers found that the isolated bacteria were only able to produce about half of the proteins they needed. It needs an algae host to provide the rest of the proteins it needs to survive.
“This is one of the characteristics of when something moves from an endosymbiont to an organelle,” Zea says. “They start throwing away bits of DNA, the genome gets smaller and smaller, and they start relying on the mother cell to transport those gene products, or the proteins themselves, into the cell.”
The research team believes this indicates that UCYN-A may be considered a complete organelle.They are We named it “nitroplast.” And it potentially began to evolve about 100 million years ago. This seems like a long time to the human sense of time, but compared to mitochondria and chloroplasts, it is only a millisecond in evolutionary time.
Many other questions about UCYN-A and its algae host remain unanswered, and the research team also plans to elucidate the behavior of UCYN-A and its algae and study different strains. Further studies of nitroplasts can also determine whether they are present in other cells and what their benefits are. For example, it has a wide range of possible applications in the agricultural sector.
“This system represents a new perspective on nitrogen fixation and may provide clues as to how such organelles can be incorporated into crops,” Cole said.
Zeel said scientists are likely to discover other organisms with similar evolutionary stories to UCYN-A, but this discovery is “textbook-ready.”
