Today’s microbe of the month is the versatile Bacillus subtilis.
Stats
Shape: Rod-shaped
Diet: Detritus
Environment: Varies. Commonly found in soils but can also be associated with freshwater and marine samples as well as mammal and bird microbiomes.
Gram stain: Negative
Pathogenic: No
These rod-shaped bacteria have been found in environments across the globe. They’re exceptionally hardy and can metabolize different sugars depending on their Ecotype and genome. B. subtilis has also shown resilience to saline shock (a sudden change in the salt content of their environment) and are resistant to drying out. In fact, this type of bacteria is common in the dry desert sands of Death Valley, CA, which is the hottest, driest place in North America!
How do B. subtilis cells survive in the brutally hot and dry soil of a desert? One thing they have going for them is the ability to form endospores. Endospores are a little like escape pods; bacteria only release them in harsh conditions, but they can be the key to survival. Not necessarily survival of the exact cell, but at least its DNA. Endospores are special structures. They contain the entire genome, some ribosomes, and some specialized proteins, but are smaller than a normal cell and the entire structure is enveloped bya super thick protective layer called the spore coat. These endospores have extremely little metabolic activity and can survive for years. In Death Valley they probably only need to remain dormant during the summer, but since no one has tested this, we don’t really know for sure- perhaps they’re only active during the mild, wet spring months, or perhaps they wait for years until an especially good year for detritus comes along.
The Angry Microbe 