Jodi Switzer Blum
John F. Stolz
F. Robert Tabita
Brian Witte
Gary M. King
Joanne M. Santini
Ron Oremland
Shelley E. Hoeft
2007
<p><span>A facultative chemoautotrophic bacterium, strain MLHE-1</span><span class="jp-sup">T</span><span>, was isolated from Mono Lake, an alkaline hypersaline soda lake in California, USA. Cells of strain MLHE-1</span><span class="jp-sup">T</span><span> were Gram-negative, short motile rods that grew with inorganic electron donors (arsenite, hydrogen, sulfide or thiosulfate) coupled with the reduction of nitrate to nitrite. No aerobic growth was attained with arsenite or sulfide, but hydrogen sustained both aerobic and anaerobic growth. No growth occurred when nitrite or nitrous oxide was substituted for nitrate. Heterotrophic growth was observed under aerobic and anaerobic (nitrate) conditions. Cells of strain MLHE-1</span><span class="jp-sup">T</span><span> could oxidize but not grow on CO, while CH</span><span class="jp-sub">4</span><span> neither supported growth nor was it oxidized. When grown chemoautotrophically, strain MLHE-1</span><span class="jp-sup">T</span><span> assimilated inorganic carbon via the Calvin–Benson–Bassham reductive pentose phosphate pathway, with the activity of ribulose 1,5-bisphosphate carboxylase (RuBisCO) functioning optimally at 0.1 M NaCl and at pH 7.3. Strain MLHE-1</span><span class="jp-sup">T</span><span> grew over broad ranges of pH (7.3–10.0; optimum, 9.3), salinity (15–190 g l</span><span class="jp-sup">−1</span><span>; optimum 30 g l</span><span class="jp-sup">−1</span><span>) and temperature (13–40 °C; optimum, 30 °C). Phylogenetic analysis of 16S rRNA gene sequences placed strain MLHE-1</span><span class="jp-sup">T</span><span> in the class </span><span class="jp-italic">Gammaproteobacteria</span><span>(family </span><span class="jp-italic">Ectothiorhodospiraceae</span><span>) and most closely related to </span><span class="jp-italic">Alkalispirillum mobile</span><span> (98.5 %) and </span><span class="jp-italic">Alkalilimnicola halodurans</span><span> (98.6 %), although none of these three haloalkaliphilic micro-organisms were capable of photoautotrophic growth and only strain MLHE-1</span><span class="jp-sup">T</span><span> was able to oxidize As(III). On the basis of physiological characteristics and DNA–DNA hybridization data, it is suggested that strain MLHE-1</span><span class="jp-sup">T</span><span> represents a novel species within the genus </span><span class="jp-italic">Alkalilimnicola</span><span> for which the name </span><span class="jp-italic">Alkalilimnicola ehrlichii</span><span> is proposed. The type strain is MLHE-1</span><span class="jp-sup">T</span><span> (=DSM 17681</span><span class="jp-sup">T</span><span>=ATCC BAA-1101</span><span class="jp-sup">T</span><span>). Aspects of the annotated full genome of </span><span class="jp-italic">Alkalilimnicola ehrlichii</span><span> are discussed in the light of its physiology.</span></p>
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10.1099/ijs.0.64576-0
en
International Union of Microbiological Societies
Alkalilimnicola ehrlichii sp. nov., a novel, arsenite-oxidizing haloalkaliphilic gammaproteobacterium capable of chemoautotrophic or heterotrophic growth with nitrate or oxygen as the electron acceptor
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