Isosphaera pallida ATCC 43644

Isosphaera pallida strain IS1B was isolated from a hot spring in Kah-nee-tah, Oregon, USA. It is the only budding bacterium known to glide and the only heterotrophic bacterium known to be phototactic. Cells are spherical (2.5 to 3 um) in diameter, with cell growth and division occurring by intercalary budding, resulting in filaments. The cells are salmon-colored (caused by carotenoids) and contain gas vesicles. The cells contain numerous pili but no flagella. Under some conditions cells form motile, macroscopic aggregates,or "comets". Aggregation and motility were observed in both the light and the dark, however comets were strongly phototactic. I. pallida has an unusual cell wall ultrastructure and is resistant to beta-lactam antibiotics, suggesting that it does not have a peptidoglycan cell wall, and indeed cells stain Gram-negative but lack an outer membrane (adapted from http://standardsingenomics.org/index.php/sigen/article/view/sigs.1533840/sigs.1533840_pdf and PMID 3584067). (EBI Integr8)