Answer:
Bacteroides
Sphingolipids.
Explanation:
Bacteroides are symbiotic bacteria which populates GI tract of their hosts,where they maintain general well being of the host and in return gain shelter and nutrients from the host.
However,in order to survive the fluctuating environmental factors of chemical, temperature, of the intestinal medium,these bacteria had developed highly sensitive structures to quickly detect the fluctuations, and a sequence of response mechanisms to respond accordingly to survive.
The sensor or danger signaling and response structure in the membranes of these bacteria for this purpose is called Sphingolipids. The structure sensed fluctuation in the intestinal environments and created a response pathways for the bacteria to evade the unpleasant environments,This structure was formally thought to be present in eukaryotes only.Thus why the word unusual in the question.
