What does this bacterium look like?
Alistipes is a rod of approximately 0.5 to 4 micrometers long. That is small when you know that 1,000 micrometers fit into one millimeter.
What does science already know about this bacterium?
Not much yet. The name Alistipes literally means “another tribe” because it did not originally fit well within the existing genera of gut bacteria. This bacterium was first described in 2003 only as the separate genus Alistipes.
Alistipes does not tolerate oxygen well and is therefore difficult to grow in the lab. We do know that there are several species in the gut, such as Alistipes putredinis and Alistipes finegoldii. The second species honors Sydney M. Finegold, an American researcher who studied gut bacteria.
We know that the average genome size of Alistipes varies between 2.7 and 4 million base pairs with more than 2,500 genes. This means that this bacterium can produce more than 2,500 different substances.
What is this bacterium doing in my gut?
Although Alistipes belongs to the same family of gut bacteria as Bacteroides and Prevotella, this bacterium has some different characteristics. For example, we already know that Alistipes likes proteins. These are found in meat, fish, eggs and legumes, for example. When you consume protein-rich foods, proteins end up in your intestines. Certain bacteria can use these as food. For example, Alistipes breaks down proteins and converts them into various substances. These can be useful substances, such as short-chain fatty acids. Some examples are succinate, acetate and propionate. They provide energy to your intestinal cells and thus contribute to a healthy intestinal wall (or intestinal lining).
When there is too much protein in your intestines, Alistipes can sometimes become more active. This can lead to the production of breakdown products such as ammonia or phenols during the processing of the proteins. These can in turn be less beneficial and, for example, irritate your intestinal wall. But there is no need to panic! Everything depends on the context and circumstances. Normally, your diet does not consist exclusively of protein, but also includes fiber and other nutrients for the gut bacteria. Moreover, Alistipes is not the only bacterium present in your gut, and the various gut bacteria keep each other in balance by working together.
Did you know that vitamin B2, or riboflavin, also plays an important role here? Some Alistipes species can produce riboflavin themselves. This vitamin is then released into the intestinal environment, where it contributes to the vitamin balance and is shared with other bacteria. Riboflavin plays a central role in our VIAB2L study, allowing us to investigate this further. Interesting! 🙂
In short, the role of Alistipes in the gut can be described in two ways, and this depends greatly on the circumstances. The amount and composition of Alistipes in the gut can also vary from person to person. It is quite possible that you have more or less Alistipes in your gut than your mum, neighbor, good friend, and so on. What else? Different species and strains do exist. There can be various reasons for this variation, such as different dietary patterns (for example more or less protein-rich). This provides a great deal of inspiration for further research! And our researchers are happy to roll up their sleeves and get to work. 🙂
Does this bacterium occur elsewhere?
Alistipes feels most at home in your gut. Unlike Prevotella, which belongs to the same family, Alistipes is not typically found in the vagina, saliva or on the skin.