archaea
- Research Article | Molecular Biology and PhysiologyLipid Anchoring of Archaeosortase Substrates and Midcell Growth in Haloarchaea
The subcellular organization of biochemical processes in space and time is still one of the most mysterious topics in archaeal cell biology. Despite the fact that haloarchaea largely rely on covalent lipid anchoring to coat the cell envelope, little is known about how cells coordinate de novo synthesis and about the insertion of this proteinaceous layer throughout the cell cycle. Here, we report the identification of two novel...
- Research Article | Molecular Biology and PhysiologySpecies-Specific Recognition of Sulfolobales Mediated by UV-Inducible Pili and S-Layer Glycosylation Patterns
Type IV pili can be found on the cell surface of many archaea and bacteria where they play important roles in different processes. The UV-inducible pili system of Sulfolobales (Ups) pili from the crenarchaeal Sulfolobales species are essential in establishing species-specific mating partners, thereby assisting in genome stability. With this work, we show that different Sulfolobus species have specific regions...
- Research Article | Ecological and Evolutionary ScienceMetagenomes from Coastal Marine Sediments Give Insights into the Ecological Role and Cellular Features of Loki- and Thorarchaeota
Microorganisms of the superphylum Asgard Archaea are considered to be the closest living prokaryotic relatives of eukaryotes (including plants and animals) and thus promise to give insights into the early evolution of more complex life forms. However, very little is known about their biology as none of the organisms has yet been cultivated in the laboratory. Here we report on the ecological distribution of Asgard Archaea...
- Research Article | Molecular Biology and PhysiologyThe TK0271 Protein Activates Transcription of Aromatic Amino Acid Biosynthesis Genes in the Hyperthermophilic Archaeon Thermococcus kodakarensis
The mechanisms of transcriptional regulation in archaea are still poorly understood. In this study, we identified a transcriptional regulator in the hyperthermophilic archaeon Thermococcus kodakarensis that activates the transcription of three operons involved in the biosynthesis of aromatic amino acids. The study represents one of only a few that identifies a...
- Research Article | Molecular Biology and PhysiologyCell Structure Changes in the Hyperthermophilic Crenarchaeon Sulfolobus islandicus Lacking the S-Layer
The S-layer is considered to be the sole component of the cell wall in Sulfolobales, a taxonomic group within the Crenarchaeota whose cellular features have been suggested to have a close relationship to the last archaea-eukaryote common ancestor. In this study, we genetically dissect how the two previously characterized S-layer genes as well as a newly identified S-layer-associated protein-encoding gene contribute to...
- Research Article | Applied and Environmental ScienceAnaerobic Degradation of Non-Methane Alkanes by “Candidatus Methanoliparia” in Hydrocarbon Seeps of the Gulf of Mexico
Oil-rich sediments from the Gulf of Mexico were found to contain diverse alkane-degrading groups of archaea. The symbiotic, consortium-forming “Candidatus Argoarchaeum” and “Candidatus Syntrophoarchaeum” are likely responsible for the degradation of ethane and short-chain alkanes, with the help of sulfate-reducing bacteria. “Ca. Methanoliparia” occurs as single cells associated with oil droplets. These archaea...
- Research Article | Molecular Biology and PhysiologyIdentification of Dephospho-Coenzyme A (Dephospho-CoA) Kinase in Thermococcus kodakarensis and Elucidation of the Entire CoA Biosynthesis Pathway in Archaea
CoA is utilized in a wide range of metabolic pathways, and its biosynthesis is essential for all life. Pathways for CoA biosynthesis in bacteria and eukaryotes have been established. In archaea, however, the enzyme that catalyzes the final step in CoA biosynthesis, dephospho-CoA kinase (DPCK), had not been identified. In the present study, bioinformatic analyses identified a candidate for the DPCK in archaea, which was biochemically and...
- Research Article | Molecular Biology and PhysiologyPositioning of the Motility Machinery in Halophilic Archaea
Archaea are ubiquitous single cellular microorganisms that play important ecological roles in nature. The intracellular organization of archaeal cells is among the unresolved mysteries of archaeal biology. With this work, we show that cells of haloarchaea are polarized. The cellular positioning of proteins involved in chemotaxis and motility is spatially and temporally organized in these cells. This suggests the presence of a specific...
- Research Article | Host-Microbe BiologyAntimicrobial Peptides, Polymorphic Toxins, and Self-Nonself Recognition Systems in Archaea: an Untapped Armory for Intermicrobial Conflicts
Diverse and highly variable systems involved in biological conflicts and self-versus-nonself discrimination are ubiquitous in bacteria but much less studied in archaea. We performed comprehensive comparative genomic analyses of the archaeal systems that share components with analogous bacterial systems and propose an approach to identify new systems that could be involved in these functions. We predict polymorphic toxin systems in 141...
- Research Article | Applied and Environmental ScienceMethane-Linked Mechanisms of Electron Uptake from Cathodes by Methanosarcina barkeri
Methanogenic archaea are of fundamental applied and environmental relevance. This is largely due to their activities in a wide range of anaerobic environments, generating gaseous reduced carbon that can be utilized as a fuel source. While the bioenergetics of a wide variety of methanogens have been well studied with respect to soluble substrates, a mechanistic understanding of their interaction with solid-phase redox-active compounds is...