Biology Reference
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To investigate the ability of ARC to generate long-term memory immunity, a
boost-dose with BSA alone was injected on day 180. Three weeks later, a signifi cantly
higher serum antibody response (>1 log,
p
< 0.05) was detected in ARC-
BM
/
GC
-BSA
compared with the BSA group (Figure 5B).
We further examined the IgG isotype distribution in the sera of immunized mice
on day 200. Both IgG1 and IgG2a increased antibody titers could be demonstrated in
long-term responses from ARC-
BM
/
GC
-BSA groups (Figure 6).
Figure 6.
Anti-BSA antibody isotypes induced after ARC-based immunization.
Mice were immunized
as indicated in Figure 5. Serum samples were collected three weeks after boosting and ELISA analyzed
for IgG subclasses (IgG1 and IgG2a). Values represent mean titers ± SEM.
DISCUSSION
The extreme halophilic archaea genus
Halorubrum
is worldwide distributed [22-28]
either at high altitude as well as under the sea level [15, 25, 29]. The only
Halorubrum
species so far described in South America is the
Halorubrum tebenquichense
ALT6-92
strain isolated from the water of Lake Tebenquiche at the unique environment of the
Atacama saltern, located in northern Chile at 2,300 m above sea level [15]. Here we
report the finding of new
H. tebenquichense
non alkaliphilic strains in a salt flat from
the littoral of the Argentinean Patagonia, the Salina Chica in Península de Valdés (42°
32' S, 63° 59' W), at the province of Chubut. Remarkably, the Salina Chica is sepa-
rated from Lake Tebenquiche by the highest (nearly 7,000 m) and younger (70 million
years) mountains in America, the Cordillera de los Andes, distant 2,500 km south-east
away and placed 40 m below sea level in a zone of temperate weather.
The membranes of extremely halophilic archaea such as
H. tebenquichense
have
several unique characteristics that vary little within specifi c genera [30]. Phospholip-
ids with ethanolamine, inositol, and serine head groups are generally absent and specifi c
