On the trail of an ancient survivor

24 July 2012

Sponges have a lot to relate: And Mainz molecular biologist Professor Dr. Werner E. G. Müller has been showing the world exactly what they have to tell us over the past few decades. In an interview he talks about this long underestimated organism, its significance to research, and its potential to help people in so many different ways.
 

"This is a sponge." Professor Dr. Werner E. G. Müller places a glass tube the size of a human forearm on the table. There is an incredibly filigree structure within: the skeleton of a deep-sea Euplectella sponge. In the muted light, it seems to emit a while glow. The innumerable silk-like strands combine to form a harmonious whole – it could almost be the model for a futuristic skyscraper.

"Twenty years ago, barely anybody believed that it was possible to learn anything new from these types of sponges." The professor of the Institute of Physiological Chemistry at Mainz University Medical Center has changed that perception entirely, something he is now explaining.

The source of all animals

The blinds in Müller's office remain closed against the intense summer sunlight. Individual rays penetrate through them, softening the contours in the room. It feels a little like being in an aquarium. In the thick of the action: the sponge.

"This is the earliest multicellular organism. It was in 1995 that we made the key discovery here in Mainz, meaning that we were able to identify the sponges as the source of all animals." Their ancestors were already around as far back as 800 million years ago. "Sponges are masters of survival." They were the only species to survive the mass extinction of global fauna 540 million years ago. They then formed the basis for the explosive expansion of animal life during the Cambrian period.

"Sponges could survive for another 300 to 400 million years," says Müller "We human beings may survive another five million." So it seems obvious that young Homo sapiens could learn something from the good old sponge.

Sponges live longer

"We have discovered that all these animals have structural characteristics and regulation mechanisms seen in other multi-celled organisms." As an early form of life, the sponge is less specialized than a human being, for example, and is thus less susceptible. "The oldest living sponge was born 10,000 years ago in South China."

The professor can endlessly spout such astounding facts. He has dived for sponges in Lake Baikal, he has visited their relatives in a mountain lake at the foot of Mt. Everest, and has observed tree sponges in the Amazon region – a curious species which lives for nine months above water and three months below.

Now the researcher and his colleagues are concentrating on discovering what benefits sponges can provide. "We always follow a route that starts with molecular biology and move on through biology to practical application," explains Müller, before going on to describe some facets of his research.

A wonderful skeleton

The finely structured sponge skeleton is composed of silicate. "We discovered that there is a particular enzyme that is responsible for generating what is essentially a form of quartz glass. Nobody had ever seen anything like it before: An enzyme that produces an inorganic substance. If Schott, the glass manufacturer, wanted to produce anything like it, they would need to work at temperatures of 1.500°C; but the animals can do it at 20°C and lower."

At first glance, a sponge's glass skeleton does not seem to have a lot in common with human bones. "However, our American colleagues have found out that we need silicate for bone formation. Wherever bones grow, there's a lot of silicate." Aging bones can be a problem if osteoporosis develops. Sponges can help. How about creating a silicate frame to help grow bones?

And there are other possibilities. If a sponge loses a part of its body, it can regenerate it. "Stem cells constitute 80 percent of all its body cells." They are ready to specialize and create a replacement. Silicate plays a role here as well: "It causes stem cells to construct a skeleton."

A framework with nerve

It seems that the quartz glass framework does more than is normally expected from a skeleton. A sponge does not have a nervous system but it looks as if its skeleton has certain neural functions. "Could we use this template to generate nerve-like structures?"

He moves on from discussing sponges themselves to a consideration of their friends and helpers. "Sponges have perfected their symbiotic relationship with bacteria and algae." Substances are thus created that could be useful as drugs. "These are already playing a role in anti-tumor treatment and leukemia therapy."

Sponges may even turn out to play a staring role when it comes to the treatment of surfaces. Marine fouling involves the development of an organic layer on a ship's hull over time and its colonization by barnacles. This can have a significantly detrimental effect on sailing speeds. However, sponges have known for millions of years how to resist the build-up of such surface accretions. The antifouling paint that was used in the past, TBT, is now banned. But sponges could provide an alternative.

EUR 6 million for BlueGenics

There is one important aspect: It is not the intention of Müller and his colleagues to harvest sponges to extract substances on the large scale. They have a different way of doing things. One of their goals is to develop genetic blueprints. They implant sponge genes in microorganisms that are easy to cultivate. The EU Commission has just provided some EUR 6 million to finance their research. The BlueGenics international research project will start this year and will be coordinated from Mainz.

The Mainz team and its sponges are gleaning international respect and support. About two years ago, Müller was awarded the Advanced Grant of the European Research Council, which is the highest endowed research grant in the EU and is worth EUR 2.2 million. And the BIOTECmarin excellence center that he helped form is flourishing with its concept of using biomaterial from the sea. "When it comes to sponges, we in Mainz are simply marvelous," says Müller. "The conditions here are great."

Goethe, Genscher, and sponges

Müller has much to say and talks for two hours while Euplectella continues to glow in the half-dark of his office. The molecular biologist likes to go off on the occasional tangent. His subjects include Goethe's scientific writings, Schiller's sloppiness in his writing about the Thirty Years War, meetings with Hans-Dietrich Genscher, and his long conversation with China's Prime Minister Wen Jiabao. However, the professor always comes back to his sponges. "There's still a lot they can tell us," he says on the way from his office to the elevator, where he says goodbye.

Outside the sun is warm and somewhat glaring. It is like returning to reality from a fantasy world.