from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A large, thick-walled, transparent cell that occurs at intervals along the filaments of certain cyanobacteria.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A specialized nitrogen-fixing cell formed by some filamentous cyanobacteria.
from the GNU version of the Collaborative International Dictionary of English
- n. A cell larger than the others, and of different appearance, occurring in certain algæ related to nostoc.
from The Century Dictionary and Cyclopedia
- n. In botany, one of a class of abnormal cells found in algæ of the order Nostocaceæ.
To establish the first, Hoover showed samples from meteorites of forms that appeared to have cells and cell walls, that were in the process of splitting or otherwise reproducing, that were attached to the rock with what he identified as a primitive stalk called a basal heterocyst, and that had lived in what appeared to be colonies of microbes known to coexist on Earth.
The fact that the CS-505 and D9 genomes are small and streamlined compared to those of other filamentous cyanobacterial species and the lack of the ability for heterocyst formation in strain D9 allowed us to define a core set of genes responsible for each trait in filamentous species.