Comprehensive coverage

Researchers have discovered a bacterium that stores huge amounts of arsenic

The discovery, made by researchers from Tel Aviv University, may pave the way for the development of a cheap and effective way to clean drinking water of arsenic - the most common toxic pollutant in the world

Researchers have discovered a bacterium residing in the common sponge Theonella Swinhoe, which stores huge amounts of the toxic chemical element arsenic, and can help develop methods for effectively cleaning water from the toxin. Source: Courtesy of Tel Aviv University.
Researchers have discovered a bacterium residing in the common sponge Theonella Swinhoe, which stores huge amounts of the toxic chemical element arsenic, and can help develop methods for effectively cleaning water from the toxin. Source: Courtesy of Tel Aviv University.

Researchers at Tel Aviv University's Department of Zoology have discovered a unique bacterium that stores within it huge amounts of the toxic chemical element arsenic, which is currently considered the number one polluter of ground water in the world. The researchers hope that their discovery will enable the development of an effective method for cleaning water from the resistant element, which currently contaminates the drinking water of tens of millions of people around the world.

The bacterium, which resides in the common sponge Theonella Swinhoei, was studied by Dr. Rei Keren and Dr. Boaz Meisel, in the sponge research laboratory of Prof. Micah Ilan. The research was carried out in collaboration with Prof. Boaz Pokroy from the Technion and with Dr. Sirin Pekra from the Lawrence National Laboratory in Berkeley, USA.

The groundbreaking research, which arouses great interest in the international scientific community, Published on 25.2.17 in the journal Nature Communications.

A new kind of bio-mineral

"Sponges are the most ancient animals that exist today on Earth," explains Prof. Ilan. "These are sedentary creatures, which continuously filter the water in which they live, and collect many substances from it. In a previous study, which we conducted a few years ago, we discovered that the sponge 'Theonella Savihoi', and especially its variety that lives in the Red Sea, stores a huge amount of the elements arsenic and barium - up to a million times the concentration in its marine environment! In the current study, we wanted to find out what is the factor inside the sponge responsible for the accumulation of arsenic."

Dr. Keren says that from the beginning he thought it was a bacterium. To test this hypothesis, the researchers separated the cells of the sponge itself from the many bacteria living within it, and found that indeed, arsenic is found in the bacterial community. An examination with a scanning electron microscope revealed that a certain bacterium, called 'Antotheonella', is the one that stores the element, which is toxic to all forms of life. How does he do it?

Rigorous tests using advanced means to identify substances revealed an amazing finding, the likes of which has not yet been observed in the biological world: "We discovered that the bacterium carries out a chemical process inside its body of linking the arsenic dissolved in water and the element calcium," says Dr. Keren. "The product, called pharmacolyte, is a solid crystal, which is not toxic at all. In this way, the arsenic is preserved inside the bacteria's body, and there is no danger of it leaking out, dissolving again in water, and becoming toxic again." It is important to note that the same bacteria also stores the chemical element barium in a similar way - it is also a common pollutant that harms our health. In fact, it can be said that the bacterium functions within the sponge as an organ for detoxification, a sort of 'substitute' for the liver of more developed animals.

For the scientific community, the discovery presents many innovations: first, the concentration of arsenic in the bacterium's body is the highest that has ever been measured anywhere on the entire surface of the earth - including in geological deposits! Also, science knows very few bacteria that are able to produce minerals within their bodies, and this is the first time that a bacterium has been discovered that produces crystalline arsenic in the form of a pharmacolite. Moreover, the pharmacolite itself is a substance known as a geological deposit, but so far its biological production has never been observed. In other words, the pharmacolite produced by the bacterium Entotheonella is a completely new type of biomineral!

In the next phase of his work, Dr. Keren wishes to investigate the genome of the Entotheonella bacterium, with the aim of locating the genes involved in the process of storing arsenic and barium and turning them into harmless solids. Another direction of future research is the search for similar bacteria that live in soil or groundwater - something that may significantly shorten the process of developing a technology for cleaning drinking water.

"Dissolved arsenic is a very resistant substance, which remains in the environment forever, and to this day no effective way has been found to remove it from the groundwater," concludes Prof. Ilan. "We hope that our discovery will help in the future for the development of a cheap and effective way to clean groundwater and drinking water from arsenic. Such a development may save the health and even the lives of tens of millions of people."

For the full article

5 תגובות

    1. :
    A possible human arsenic requirement is 12 mcg/day


    Possible function
    Arsenic plays a role that affects the conversion of methionine (an amino acid) to its metabolites taurine (another amino acid), labile methyl and the polyamines; involved in the methylation of various biomolecules (eg, histones).
    Dietary needs and sources
    Human requirements most likely near 12mcg per day; rich food sources can be fish, grain and cereal products.


    Arsenic may be essential for humans
    To date no specific biological function of arsenic has been found. Recent findings suggest that arsenic has a function that influences arginine and zinc metabolism in mammals. Arsenic may do this through a function in some enzyme system(s) because arsenic can either activate or inhibit enzymes in vitro. Another possibility is that arsenic has a structural role as part of a phospholipid membrane.
    Although arsenic has been synonymous with poison for centuries, and a number of reports have associated arsenic with some forms of cancer, it is actually much less toxic than selenium, a trace element with a well-established nutritional value. Toxic quantities of arsenic generally are measured in milligrams and the ratio of the toxic to nutritional dose for rats apparently is near 1250. Thus any beliefs that any form or amount of arsenic is unnecessary, toxic, or carcinogenic are unrealistic and of concern. The findings described in the preceding show that there are safe and, most likely, necessary levels of arsenic intakes that would allow optimal health for animals and humans throughout a lifetime.

  2. my father
    The link you (!) provided further reinforces my point... there are very few species that are known to need arsenic. Man is not among them...

  3. for miracles
    First of all, the sentence you brought from Wikipedia does not contradict what I wrote.
    Second, arsenic is one of the trace elements that are needed in very small amounts of around 10 micrograms per day.
    Since arsenic has been used as a poison for many years, and there is probably an excess of it in our Sava, which is more of a problem, there are probably many more articles and studies on the topic of arsenic toxicity and less on arsenic as a microelement that is needed in the body, I rely on this from my memory from biochemistry studies... perhaps on websites that deal with nutrition and microelements You can find more material on this in the food.
    For example here:

  4. my father
    Where does this information come from? Wikipedia claims otherwise:
    Some evidence indicates that arsenic is an essential trace mineral in birds (chickens), and in mammals (rats, hamsters, and goats). However, the biological function is not known

    On what basis do you say Wikipedia is wrong?

  5. It is important to note that arsenic is not just a poison.
    Arsenic is one of the minerals that are necessary in the human body, it is involved in enzymatic processes in the functioning of the nervous system, etc., although in very small quantities, but it is impossible to live without arsenic.

Leave a Reply

Email will not be published. Required fields are marked *

This site uses Akismat to prevent spam messages. Click here to learn how your response data is processed.