Scientists find bacteria living on fish brains

Sub : Sci

Sec: Msc

Context:

A new study challenges the long-held belief that the human brain is sterile, protected by the blood-brain barrier, a tightly locked layer of cells that defend your brain from harmful substances. The study reveals that bacteria not only make their way into the brain, but they can also thrive there.
Researchers from the University of New Mexico studied salmon and trout to investigate the presence of bacteria in their brains.

Findings of the study:

Using DNA extraction and microscopic imaging, they identified living bacteria in the fish’s olfactory bulbs, which connects to the nasal cavity, but also in deeper regions of the brain.
One of the striking findings of the study was the direct visual evidence of bacteria crossing the blood-brain barrier.
These microbes seem to have unique adaptations, like producing polyamines that open tight junctions in the blood-brain barrier, allowing them to enter and survive in the brain.
The study suggests that some bacteria may have colonized the brain before the blood-brain barrier fully evolved, while others may have infiltrated via the gut or bloodstream over time.
The researchers propose that these microbes could influence brain function, similar to how the gut microbiome affects digestion, immunity, and mood.

Implications for Human Brain Microbiome:

While the study focused on fish, the findings raise questions about the presence of a brain microbiome in other vertebrates, including humans. If bacteria can thrive in fish brains, it opens the possibility that human brains could also harbour microbial life.