Nav: Home

Russian scientists found out how a male-hating bacterium rejuvenates

April 01, 2019

A team from Immanuel Kant Baltic Federal University together with their Russian colleagues carried out genetic analysis of the symbiotic bacterium Wolbachia that prevents the birth and development of males in different species of arthropods. It turned out that the microorganisms exchanged their genes to rejuvenate. The results of the study were published in the Molecular Phylogenetics and Evolution journal.

Different species may have different relationships with each other: some compete for limited resources, and some feed off their hosts. Nevertheless, if two species cohabitate in some way, it is called symbiosis, and its participants are symbionts. Some symbionts can be inherited.

The Wolbachia bacterium is the most widespread symbiont in the biosphere. Many arthropods and some nematode worms have it. The bacterium lives in the reproductive tissues and is inherited from mother to progeny via the oocytes of infected females. Scientists believe that currently these bacteria are being transformed into a new cell organelle.

Wolbachia manipulates the reproductive process of its host. For example, it may "forbid" infected males to inseminate healthy females to prevent them from getting offsprings. All embryos die on early stages of development, and scientists are still unable to understand how the bacteria manage to do it. In other species the bacterium increases the share of females in the population to spread the infection. To do so, it feminizes genetic males or causes thelytokous parthenogenesis -- a process when female progeny is produced without insemination. However, sometimes Wolbachia can be very useful for its host: it synthesizes vitamins and suppresses harmful mutations and even some viruses.

According to the scientists, these bacteria can be very different from the genetic point of view in one host species and very similar -- in different ones. It indicates that the bacterium has several individual symbiotic relations. So, there are several supergroups -- phyletic lines or tribes of Wolbachia.

Although the bacterium has been discovered in 1924, a lot is still unknown about it, including the beginning of its symbiosis with arthropods and the mechanism of its transmission from one species to another. Moreover, how it controls the reproductive system of its host is also unclear.

Previously the authors of the work analyzed phylogenetic relations between different Wolbachia strains and discovered many contradictions in its evolutionary history. They are associated with large-scale horizontal gene transfer -- a process in which an organism transfers its genetic material to another organism that is not its progeny. For example, many centuries ago plants allowed photosynthesizing cyanobacteria to leave in their cells. With time they turned into chloroplasts and transferred a lot of genes to their hosts genomes.

To identify the phylogenetic relations the authors had used a special approach -- they classified different Wolbachia bacteria by alleles (variations) of each gene and looked for irregular accumulation of nucleotide substitutions. In the course of this work the authors studied Wolbachia in mosquitoes using the same method, i.e. by comparing their alleles to the alleles of the same bacteria in other species. They had to understand where the mosquitos got the symbiont from.

"We analyzed genetic profiles of different Wolbachia supergroups and concluded that the bacteria in mosquitoes are very similar to those found in lepidopteras and in one case also in ants. We don't know yet why it happened. However, we assume the bacteria may be transferred by the ticks that live on the bodies of these insects", said Yury Ilinsky, a co-author of the work, PhD in Biology, and a specialist of Immanuel Kant Baltic Federal University.

The scientists found out that different Wolbachia bacteria exchange genetic information. This way they can rejuvenate and therefor mend their broken genes. The exchange usually takes place among the bacteria of the same supergroup, but sometimes remote bacteria are involved as well. It means that the bacterium changes hosts more often than the scientists believed, and also that it's older than previously estimated.

"Our global goal is to understand the pattern of genetic distribution of Wolbachia in arthropods. After that we would like to understand how and at what rate it changes hosts", concluded Yury Ilinsky.

The participants of the work also represented Lomonosov Moscow State University, Sechenov First Moscow State Medical University, and Vavilov Institute of General Genetics of RAS.
-end-


Immanuel Kant Baltic Federal University

Related Bacteria Articles:

Conducting shell for bacteria
Under anaerobic conditions, certain bacteria can produce electricity. This behavior can be exploited in microbial fuel cells, with a special focus on wastewater treatment schemes.
Controlling bacteria's necessary evil
Until now, scientists have only had a murky understanding of how these relationships arise.
Bacteria take a deadly risk to survive
Bacteria need mutations -- changes in their DNA code -- to survive under difficult circumstances.
How bacteria hunt other bacteria
A bacterial species that hunts other bacteria has attracted interest as a potential antibiotic, but exactly how this predator tracks down its prey has not been clear.
Chlamydia: How bacteria take over control
To survive in human cells, chlamydiae have a lot of tricks in store.
More Bacteria News and Bacteria Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#534 Bacteria are Coming for Your OJ
What makes breakfast, breakfast? Well, according to every movie and TV show we've ever seen, a big glass of orange juice is basically required. But our morning grapefruit might be in danger. Why? Citrus greening, a bacteria carried by a bug, has infected 90% of the citrus groves in Florida. It's coming for your OJ. We'll talk with University of Maryland plant virologist Anne Simon about ways to stop the citrus killer, and with science writer and journalist Maryn McKenna about why throwing antibiotics at the problem is probably not the solution. Related links: A Review of the Citrus Greening...