(ORDO NEWS) — Taking away part of the food from the amoeba, chlamydia in return neutralize the giant viruses penetrating it.
Perhaps it was this confrontation that led to the emergence of unusual viruses and complex life forms on Earth.
Microbiologists from the University of Vienna (Austria) decided to find out what would happen if a single-celled organism like an amoeba was simultaneously infected with bacteria and viruses.
The result interested scientists: once inside the amoeba, the Parachlamydia acanthamoebae bacteria turned into an “anti-virus system”, which allows them to be considered full-fledged symbionts.
This phenomenon could have a key impact on the formation of food chains and the emergence of the most complex giant viruses (how exactly is described in the last two paragraphs of the news).
Chlamydia species Parachlamydia acanthamoebae – bacteria about 0.0005 mm in size, which are practically not found in free form.
Typically, they live inside amoebas, receiving nutrients, protection from toxins, and help in reproduction from them.
According to Patrick Arthofer, lead researcher on the study, chlamydia usually slows down the growth of the host organism, which is why they are considered parasites. But in the case of amoebas, the benefits clearly outweigh the harm.
Researchers came to this conclusion when they tried to infect chlamydia amoebae with giant viruses. These viruses are even larger than bacteria: their length reaches 0.0015 millimeters.
Giant viruses (in particular, mimiviruses) also live inside amoebas, where they were first seen in 1992 using a conventional light microscope. Measuring 0.5 millimeters, amoebas have become a real battlefield between bacteria and viruses.
Having penetrated the amoeba, giant viruses rebuild it from the inside, turning it into a virus factory . Instead of performing their usual functions, amoeba organelles are taken to churn out new copies of the virus.
This threatens to quickly kill both the amoeba itself and the chlamydia that live inside it. Therefore, Parachlamydia acanthamoebae have learned to defend themselves.
Chlamydia allow giant viruses to enter the amoeba, but do not allow it to be rebuilt into a virus factory. Thus, they completely suppress the replication of viruses. Amoebas continue to live, grow and multiply.
But with chlamydia “on board”, amoeba divide much more slowly than without them: in 22.7 hours versus 17.3 hours.
So antiviral protection from bacteria still does not cost amoeba for free, which is consistent with the parasitic essence of chlamydia.
The work of Austrian microbiologists is especially interesting because it models a situation typical of natural conditions.
In nature, amoeba are almost always infected with either bacteria, or viruses, or bacteria and viruses at the same time.
Scientists even refer to amoebas as the “melting pots of evolution,” in which viruses and bacteria vie for control of vital cellular machinery.
And it seems that it is this confrontation that led to the fact that the mimiviruses, tupanoviruses and other giant viruses became so large and complex.
Moreover, the antiviral defense of amoebas by bacteria could play a key role in the formation of food chains.
The fact is that bacteria contain important nutrients that small animals like crustaceans cannot get directly.
These animals eat amoebas, which in turn feed on bacteria. If the amoeba dies from viruses, it releases nutrients back into the environment, where only bacteria can extract them.
Thus, if chlamydia had not learned to protect their hosts from viruses, then the formation of food chains would have stalled at the level of protozoa.
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