Methylobacterium
A genus of gram-negative, aerobic, facultatively methylotrophic rods occurring singly or occasionally in rosettes. Members of this genus are usually motile and are isolated from soil, dust, fresh water, lake sediments, leaf surfaces, rice, air, and hospital environments. (From Bergey's Manual of Determinative Bacteriology, 9th ed)
Pyrrolizidine Alkaloids
A group of ALKALOIDS, characterized by a nitrogen-containing necine, occurring mainly in plants of the BORAGINACEAE; COMPOSITAE; and LEGUMINOSAE plant families. They can be activated in the liver by hydrolysis of the ester and desaturation of the necine base to reactive electrophilic pyrrolic CYTOTOXINS.