Halobacterium
A genus of HALOBACTERIACEAE whose growth requires a high concentration of salt. Binary fission is by constriction.
Halobacterium salinarum
A species of halophilic archaea found in salt lakes. Some strains form a PURPLE MEMBRANE under anaerobic conditions.
Bacteriorhodopsins
Rhodopsins found in the PURPLE MEMBRANE of halophilic archaea such as HALOBACTERIUM HALOBIUM. Bacteriorhodopsins function as an energy transducers, converting light energy into electrochemical energy via PROTON PUMPS.
Gene Expression Regulation, Archaeal
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in archaea.
Purple Membrane
Functionally and structurally differentiated, purple-pigmented regions of the cytoplasmic membrane of some strains of Halobacterium halobium. The membrane develops under anaerobic conditions and is made almost entirely of the purple pigment BACTERIORHODOPSINS. (From Singleton & Sainsbury Dictionary of Microbiology and Molecular Biology, 2d ed)
Carotenoids
Halobacteriales
An order of extremely halophilic archaea, in the kingdom EURYARCHAEOTA. They occur ubiquitously in nature where the salt concentration is high, and are chemoorganotrophic, using amino acids or carbohydrates as a carbon source.
Genes, Archaeal
The functional genetic units of ARCHAEA.
Halobacteriaceae
A family of extremely halophilic archaea found in environments with high salt concentrations, such as salt lakes, evaporated brines, or salted fish. Halobacteriaceae are either obligate aerobes or facultative anaerobes and are divided into at least twenty-six genera including: HALOARCULA; HALOBACTERIUM; HALOCOCCUS; HALOFERAX; HALORUBRUM; NATRONOBACTERIUM; and NATRONOCOCCUS.
Genome, Archaeal
The genetic complement of an archaeal organism (ARCHAEA) as represented in its DNA.
Retinaldehyde
A carotenoid constituent of visual pigments. It is the oxidized form of retinol which functions as the active component of the visual cycle. It is bound to the protein opsin forming the complex rhodopsin. When stimulated by visible light, the retinal component of the rhodopsin complex undergoes isomerization at the 11-position of the double bond to the cis-form; this is reversed in "dark" reactions to return to the native trans-configuration.
Archaea
One of the three domains of life (the others being BACTERIA and Eukarya), formerly called Archaebacteria under the taxon Bacteria, but now considered separate and distinct. They are characterized by: (1) the presence of characteristic tRNAs and ribosomal RNAs; (2) the absence of peptidoglycan cell walls; (3) the presence of ether-linked lipids built from branched-chain subunits; and (4) their occurrence in unusual habitats. While archaea resemble bacteria in morphology and genomic organization, they resemble eukarya in their method of genomic replication. The domain contains at least four kingdoms: CRENARCHAEOTA; EURYARCHAEOTA; NANOARCHAEOTA; and KORARCHAEOTA.
DNA, Archaeal
Deoxyribonucleic acid that makes up the genetic material of archaea.
Pyruvate Synthase
Photochemistry
Photochemistry is the study of chemical reactions induced by absorption of light, resulting in the promotion of electrons to higher energy levels and subsequent formation of radicals or excited molecules that can undergo various reaction pathways.
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Halococcus
A genus of extremely halophilic HALOBACTERIACEAE with coccoid cells occurring singly or as pairs, tetrads, or irregular clusters. They are found in neutral salt lakes, marine salterns, saline soils and seawater.
Natronobacterium
A genus of rod-shaped, extremely halophilic HALOBACTERIACEAE which grows in alkaline conditions. They are strictly aerobic and some strains are motile. Natronobacterium is found in soda lakes, alkaline salterns, and soda soils.
Haloferax volcanii
A species of halophilic archaea found in the Dead Sea.
Base Sequence
Chromosomes, Archaeal
Spectrophotometry
The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
Amino Acid Sequence
RNA, Archaeal
Ribonucleic acid in archaea having regulatory and catalytic roles as well as involvement in protein synthesis.
Hydrogen-Ion Concentration
Photophosphorylation
The use of light to convert ADP to ATP without the concomitant reduction of dioxygen to water as occurs during OXIDATIVE PHOSPHORYLATION in MITOCHONDRIA.