In:
Journal of Bacteriology, American Society for Microbiology, Vol. 190, No. 5 ( 2008-03), p. 1743-1750
Abstract:
Nanoarchaeum equitans and Ignicoccus hospitalis represent a unique, intimate association of two archaea. Both form a stable coculture which is mandatory for N . equitans but not for the host I . hospitalis . Here, we investigated interactions and mutual influence between these microorganisms. Fermentation studies revealed that during exponential growth only about 25% of I . hospitalis cells are occupied by N . equitans cells (one to three cells). The latter strongly proliferate in the stationary phase of I . hospitalis , until 80 to 90% of the I . hospitalis cells carry around 10 N . equitans cells. Furthermore, the expulsion of H 2 S, the major metabolic end product of I . hospitalis , by strong gas stripping yields huge amounts of free N . equitans cells. N . equitans had no influence on the doubling times, final cell concentrations, and growth temperature, pH, or salt concentration ranges or optima of I . hospitalis . However, isolation studies using optical tweezers revealed that infection with N . equitans inhibited the proliferation of individual I . hospitalis cells. This inhibition might be caused by deprivation of the host of cell components like amino acids, as demonstrated by 13 C-labeling studies. The strong dependence of N . equitans on I . hospitalis was affirmed by live-dead staining and electron microscopic analyses, which indicated a tight physiological and structural connection between the two microorganisms. No alternative hosts, including other Ignicoccus species, were accepted by N . equitans . In summary, the data show a highly specialized association of N . equitans and I . hospitalis which so far cannot be assigned to a classical symbiosis, commensalism, or parasitism.
Type of Medium:
Online Resource
ISSN:
0021-9193
,
1098-5530
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2008
detail.hit.zdb_id:
2968-3
detail.hit.zdb_id:
1481988-0
SSG:
12
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