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The queen's perfume - September 2008

Can a smell affect social behaviour? Without a doubt. Let off an unpleasant one and those closest to you will move somewhere else. Likewise, an agreeable scent will keep them hovering in your vicinity. It’s an old trick. Flowers and animals have been using smells for millions of years to ward off predators or to attract individuals for the sake of reproduction. So it does not come as a surprise to learn that ants use the same kind of technique as a means of communication and social interaction. However, it is not so much the odour but the capacity to detect it that is at the basis of two types of social behaviour in a species of red fire ant, Solenopsis invicta – the ecological pest. This particular ant either belongs to a colony that has only one queen (monogyne) reigning over it or to a far larger colony which is ruled by several queens (polygyne). In the 1990s, scientists discovered that the basis of a monogyne or a polygyne colony amounted to the existence of only one protein: pheromone-binding protein. (PDF version - 63k bytes)

Swiss-Prot cross references

Pheromone-binding protein Gp-9, Solenopsis invicta (Red imported fire ant) : Q8WP90

Take a walk on the genome - August 2008

What? No issue in July? A number of our regular readers may have noticed that – for the first time in a short decade – no article appeared during the month of July. And time has only just given us the opportunity to squeeze one into a month of August about to end. What happened? 2008 marks the 10th anniversary of the Institute. About a year ago, we pondered on the idea of conceiving an exhibition which would not only celebrate this little milestone but would also present the world of bioinformatics in as attractive a way as possible to non-scientists. It was not an easy task. For many, the word ‘bioinformatics’ is as sexy as the word ‘pots’, and the work carried out is as attractive as the bottom of a cake tin. Despite this and thanks to a year’s collaboration with scientists, writers and graphic designers – and the financial support of a few sponsors – our exhibition ‘Chromosome Walk, a saunter along the human genome’ is about to celebrate its opening, on September 1st in Geneva’s botanical gardens. (PDF version - 73k bytes)

Going unnoticed - June 2008

There are people who saunter through life unnoticed until something happens and reveals that they are far less ordinary than they appeared to be. The same goes for Heliobacter pylori. H. pylori is a bacterium which was discovered in the late 1800s but was forgotten for the best part of a century simply because no one had succeeded in cultivating it. Its role in causing gastric diseases was also discussed at the turn of the 19th century, only as the results were published in Polish they met with very little recognition outside Poland. And while H.pylori was being ignored, attempts were being made to study an enzyme which helps it to survive in the organisms it infects: urease. Like H.pylori, urease had to wade through waves of short-sightedness. Not only was it a common belief in those days that enzymes could not be proteins, but enzymes were also thought to exist in excessively low concentrations in plants and animals… Despite these barriers, H.pylori and urease finally triumphed at the end of the 20th century and both turned out to be singular entities. (PDF version - 452k bytes)

Swiss-Prot cross references

Urease subunit alpha, Helicobacter pylori : P14916
Urease subunit beta, Helicobacter pylori : P69996

The selfish smell - May 2008

We are surrounded by smells. Pleasant ones and not so pleasant ones, hard to distinguish ones, mild ones and strong ones. Smells are not part of our everyday life for the simple sake of pleasure. They are there for a purpose. The perfume of a flower can be used as an attractant for a potential pollinator, for instance. The scent given off by a poisonous mushroom is a way of warding off a predator and, by the same token, can be instantly recognised as toxic by an animal, thereby saving both species. Special scents are also given off by males and females when mating is in the air, and no wine grower will ever argue that a wine’s fragrance is not for the sole purpose of seduction. But what is a smell? More often than not, a scent is made up of a mixture of odorant molecules which, together, will trigger off a complex olfactory system that will ultimately let us perceive it and, if we wish to, put words to it. The very first step in such a system involves an odorant receptor to which an odorant molecule binds. Recently, a new human odorant receptor – OR7D4 – was discovered. OR7D4 is special in that it is the first receptor known to respond to a specific odorant molecule. (PDF version - 251k bytes)

Swiss-Prot cross references

Olfactory receptor 7D4, Homo sapiens (Human): Q8NG98

Molecular chastity - April 2008

Triggering off the making of a baby may seem a pretty straightforward process. Which it is, from a certain point of view. Yet, before any decisive action is undertaken by a woman and a man in order to unite their gametes, sperm – like ovules – have already been through a very complex series of developmental transformations. Such transformations ensure that only sperm and ovules of the same species get involved with one another, for example, or that once a couple of gametes has united no one else is allowed in. Properties of this sort are expressed on the molecular level both on the sperm’s and the ovule’s surface. One such molecule is a receptor known as zp3 found in mammals. Zp3 is expressed on the ovule’s surface and, though it is just one of many molecules, it is an essential one. Without it, sperm would not only be incapable of binding to the ovule’s membrane but they would also most probably miss their target altogether. (PDF version - 99k bytes)

Swiss-Prot cross references

Zona pellucida sperm-binding protein 3, Homo sapiens (Human): P21754
Zona pellucida sperm-binding protein 3, Mus musculus (Mouse): P10761
Zona pellucida sperm-binding protein 3, Rattus norvegicus (Rat): P97708