Archaeosomes Made of Halorubrum tebenquichense Total Polar Lipids - Recent Advances in Microbiology - page 106

The colonies grew in 10-20% NaCl-containing media, without Mg +2 requirements,
but optimum growth occurred at 20% NaCl, 40°C and pH 7.3-7.5. Remarkably, GC
was able to grow at increased temperature (50°C). Both colonies were non alkaliphi-
lic, aerobic, oxidase, and catalase positive. Only GC produced acid from a fructose
source. Fructose, pyruvate, trehalose, and galactose, but not starch, were used as sole
carbon and energy sources by both colonies (Table 1). Both GC and BM organisms
were chloramphenicol resistant and experienced no lysis even in the total absence of
sodium salt.

Table 1. Phenotypic characteristics of the two colonies isolated from Argentinean Patagonia and the
Halorubrum tebenquichense strain ALT6-92 isolated from Atacama saltern.

Characteristics BM GC ALT6-92 a

Growth salt concentration (% w/v)
10 + + -

15 + + +

20 + + nr

Growth at 50ºc - + +

Growth at pH I 0 - - +

Cabalase + + +

Oxidase + + +

Acid from
Xylose - - -

Fructuose - + -

Glucosa - - -

Utilization of
Fructose + + +

Piruvate + + +

Starch - - +

Trehalose + + +

Galactose + + +

Hydrolysis of starch - - -

G+C content (%) 59.5 61.7 63.2

% DNA-DNA similarity b 88.4 (94.0) 94.4 (91.9)

a Data obtained from Lizama et al., 2002
b Hybridization against H. tebenquichense. Values in parentheses are results of measurements in duplicate Symbols: +
positive result; - negative result; +/- slight mark; nr not reported.

For each isolate, a nearly complete 16S rDNA gene region (1,300 bp) was se-
quenced (GenBank accession numbers GQ182977 and GQ182978) and compared
with the same segment from other halophilic archaea. Phylogenetic analyses showed
that both isolates belong to the Archaea domain and are related to the Halorubrum
cluster, with the highest similarity to Halorubrum tebenquichense (98%). The G + C
contents of the two isolates and the reference strain ALT-92T [15] were determined.