| alcalilimnicola halodurans gen. nov., sp. nov., an alkaliphilic, moderately halophilic and extremely halotolerant bacterium, isolated from sediments of soda-depositing lake natron, east africa rift valley. | an alkaliphilic, halotolerant, gram-negative, heterotrophic, aerobic and rod-shaped organism was isolated from drying soda and at a water-covered site of lake natron, tanzania, by means of the most-probable-number technique developed for anoxygenic, phototrophic sulfur bacteria. it had an absolute requirement for alkalinity, but not for salinity; growth occurred at salt concentrations of 0-28% (w/v), with optimal growth at 3-8% (w/v) nacl. the bacterium preferentially metabolized volatile fatty ... | 2001 | 11760957 |
| metabolic versatility of haloalkaliphilic bacteria from soda lakes belonging to the alkalispirillum-alkalilimnicola group. | four new isolates were obtained from denitrifying enrichments with various electron donors using sediment samples from hypersaline soda lakes. based on 16s rrna gene analysis and dna-dna hybridization results, they were all identified as members of the gammaproteobacteria closely associated with the alkalispirillum-alkalilimnicola group. two isolates were obtained from samples enriched with nitrate as electron acceptor and h2 or polysulfide as electron donors, and another two strains were obtain ... | 2006 | 16491340 |
| alkalilimnicola ehrlichii sp. nov., a novel, arsenite-oxidizing haloalkaliphilic gammaproteobacterium capable of chemoautotrophic or heterotrophic growth with nitrate or oxygen as the electron acceptor. | a facultative chemoautotrophic bacterium, strain mlhe-1(t), was isolated from mono lake, an alkaline hypersaline soda lake in california, usa. cells of strain mlhe-1(t) 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 ... | 2007 | 17329775 |
| phylogeny and evolution of the family ectothiorhodospiraceae based on comparison of 16s rrna, cbbl and nifh gene sequences. | the occurrence of genes encoding nitrogenase and ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) was investigated in the members of the family ectothiorhodospiraceae. this family forms a separate phylogenetic lineage within the gammaproteobacteria according to 16s rrna gene sequence analysis and mostly includes photo- and chemoautotrophic halophilic and haloalkaliphilic bacteria. the cbbl gene encoding the large subunit of 'green-like' form i rubisco was found in all strains, except th ... | 2007 | 17911316 |
| toxic introns and parasitic intein in coxiella burnetii: legacies of a promiscuous past. | the genome of the obligate intracellular pathogen coxiella burnetii contains a large number of selfish genetic elements, including two group i introns (cbu.l1917 and cbu.l1951) and an intervening sequence that interrupts the 23s rrna gene, an intein (cbu.dnab) within dnab and 29 insertion sequences. here, we describe the ability of the intron-encoded rnas (ribozymes) to retard bacterial growth rate (toxicity) and examine the functionality and phylogenetic history of cbu.dnab. when expressed in e ... | 2008 | 18606739 |
| respiratory arsenate reductase as a bidirectional enzyme. | the haloalkaliphilic bacterium alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (as(iii)) to the reduction of nitrate and carbon dioxide. analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (arr). here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both ... | 2009 | 19285953 |
| aerobic carboxydotrophy under extremely haloalkaline conditions in alkalispirillum/alkalilimnicola strains isolated from soda lakes. | aerobic enrichments from soda lake sediments with co as the only substrate resulted in the isolation of five bacterial strains capable of autotrophic growth with co at extremely high ph and salinity. the strains belonged to the alkalispirillum/alkalilimnicola cluster in the gammaproteobacteria, where the ability to oxidize co, but not growth with co, has been demonstrated previously. the growth with co was possible only at an oxygen concentration below 5 % and co concentration below 20 % in the ... | 2010 | 19959573 |
| identification of a novel arsenite oxidase gene, arxa, in the haloalkaliphilic, arsenite-oxidizing bacterium alkalilimnicola ehrlichii strain mlhe-1. | although arsenic is highly toxic to most organisms, certain prokaryotes are known to grow on and respire toxic metalloids of arsenic (i.e., arsenate and arsenite). two enzymes are known to be required for this arsenic-based metabolism: (i) the arsenate respiratory reductase (arra) and (ii) arsenite oxidase (aoxb). both catalytic enzymes contain molybdopterin cofactors and form distinct phylogenetic clades (arra and aoxb) within the dimethyl sulfoxide (dmso) reductase family of enzymes. here we r ... | 2010 | 20453090 |
| voltage-gated sodium channel (nav) protein dissection creates a set of functional pore-only proteins. | many voltage-gated ion channel (vgic) superfamily members contain six-transmembrane segments in which the first four form a voltage-sensing domain (vsd) and the last two form the pore domain (pd). studies of potassium channels from the vgic superfamily together with identification of voltage-sensor only proteins have suggested that the vsd and the pd can fold independently. whether such transmembrane modularity is common to other vgic superfamily members has remained untested. here we show, usin ... | 2011 | 21746903 |