Bacteria Archives

Negative [−] log10 probabilities of recovering one spore in a 2.01 cm2 sample for a dispersal pattern of a landing plume that reaches 100 m in height and is then dispersed downwind in a 1 m/s wind (A) or a 10 m/s wind (B and C). The red box in Figure 2C indicates the region depicted in Figure 2B. -- [International Journal of Astrobiology]

Dispersal of Bacterial Spores Away From Spacecraft on the Martian Surface is Unlikely to Contaminate Subsequent Life-detection Samples

by Keith CowingNovember 11, 2026November 11, 2026

[International Journal of Astrobiology] Mitigating the forward contamination of Mars in the vicinity of a landed spacecraft is a significant concern for future life-detection experiments.

Mapping studies of the Morca Cave between 2013 and 2020. -- International Journal of Astrobiology

Analog Studies

Carotenoid-producing Bacteria from the Aphotic Zones of Morca Cave (Türkiye) and the Cave’s Relevance as a Terrestrial Analogue for Subsurface Astrobiology

by Keith CowingNovember 11, 2026November 11, 2026

[International Journal of Astrobiology] Caves serve as terrestrial analogues for extraterrestrial subsurface environments: permanently dark, nutrient-poor and physicochemically stable on biologically relevant timescales.

CSLM and electron microscopy of DADOH protocells. (a-b) CSLM micrographs of protocells (a) in control conditions and (b) formed in the presence of 300 ppm Si, stained with Rhodamine 6g. Scale bar = 10 µm. (c-d) Scanning Electron Microscopy (SEM) images of DADOH protocells formed in solution with 300 ppm Si then evaporated, showing different types of structures, such as (c) filaments and (d) spheres present in a colony-like group. -- biorxiv.org

Fossils & Paleontology

Protocells Reproduce Morphological And Chemical Signatures Of Early Microfossils

by Keith CowingOctober 7, 2026October 7, 2026

[biorxiv.org] Identification of early microfossils relies on morphological and chemical criteria assumed to be unique to life, but whether abiotic microstructures can satisfy these criteria has not been rigorously tested.

Geological map of the Dhala impact structure, India, showing the distribution of various rock types, settlements and water bodies present in the area (after Singh et al., 2021). -- biorxiv.org

Extremeophiles and Extreme Environments

Whole-Genome Metagenomics Insights Revealed a Uranium Bio-remediating Cross-Domain Microbiome in the Dhala Impact Structure, India

by Keith CowingSeptember 29, 2026September 29, 2026

[biorxiv.org] Meteorite impact structures on earth represent unique terrestrial analogues of extreme planetary environments where fractured lithologies, hydrothermal alteration, elevated concentrations of radionuclides, and prolonged water-rock interactions create ecological niches […]

Diagram of historically applied laboratory vent model systems as described in previous studies (2, 6–8). The figure was created with BioRender.com and adapted from reference 17, previously published under a CC BY license. -- Journal of Virology

Habitable Zones

Virus-integrated Laboratory Models For Habitability Studies Of Enceladus, Europa, And Titan

by Keith CowingSeptember 25, 2026September 25, 2026

[Journal of Virology]. Biogeochemical models have become critical for answering questions about the habitability of ocean worlds, especially that of early Earth.

Diversity of virus-like particle morphotypes in Asgard archaeal enrichment cultures. Negativestain transmission electron microscopy revealed diverse virus-like particles in low abundance Asgard archaeal enrichment cultures, including contractile and non-contractile head-tail phage morphotypes (A), spindle virus morphotypes (B), putative elongated or prolate capsids (C), and decorated capsids (D). Some putative capsids were associated with short tail-like structures, representative of podovirus morphotypes (E). Long filamentous structures were identified, some potentially representing filamentous viruses (F). Numerous diverse, unidentified extracellular particles were also detected (G). Scalebar = 100 nm. -- biorxiv.org

Nomenclature, Systematics, Natural History

Viruses, Proviruses and Satellites from Asgard Archaea Enrichments Reveal Complex Microbial Interactions

by Keith CowingSeptember 9, 2026September 9, 2026

[biorxiv.org] Asgard archaea are the closest known relatives of eukaryotes and are central to models of eukaryogenesis involving archaeal–bacterial symbiosis, yet the contribution of viruses remains unexplored.

Network of reactions stratified as in Fig. 5. Inorganic substrates are shown at left. Network end products are shown at top (cofactors) and at bottom (nucleotides and amino acids indicated with one letter codes). Diamond-shaped nodes indicate chemical compounds; circular nodes indicate reactions. Reactions are shaded according to their classification in table S4: (i) (dark) The reaction has been experimentally shown to proceed catalyzed by transition metals or uncatalyzed, (ii) (light shading) the reaction is part of a pathway or reaction sequence from biological substrates to products catalyzed by transition metals, (iii) (intermediate shading) the reaction type (for example transamination) has been shown to proceed catalyzed by transition metals in water, or (iv) the nonenzymatic reaction is not yet experimentally demonstrated (white circles). -- Science

Origin & Evolution of Life

Two Origins Of Life

by Keith CowingAugust 6, 2026August 6, 2026

[Heinrich-Heine University Duesseldorf] How and where did the first forms of life arise? These are the main questions driving research at the Institute of Molecular Evolution at Heinrich Heine University […]

Formation of different nanoparticles in the cell membranes of bacteria from mine water. Source: HZDR/J. Raff/E. Krawczyk-Bärsch/edited with AI

Extremeophiles and Extreme Environments

Bacteria That Convert Uranium Into A Stable Chemical Compound

by Keith CowingJuly 27, 2026July 27, 2026

[HZDR] The radioactive heavy metal uranium is usually found in the soil in a mineral-bound form but can be converted into soluble forms by environmental influences or mining activities. If […]

Recombination transferred part of archaeal YRS into non-canonical bacterial YRS. A) YRS core catalytic domain alignment from archaeal (indicated left as blue), bacterial non-canonical (purple) and bacterial canonical (pink) sequences. Both recombinant and nonrecombinant YRSs are found within all four major bacterial supergroups (Terrabacteria, Proteobacteria, PVC and FCB) B) Speciestree reconciled consensus trees reconstructed for the non-recombinant (left) and recombinant YRS sites (right). Branch lengths were estimated using NQ.bac+R10 in IQ-Tree v2.1.332. -- [biorxiv.org]

Origin & Evolution of Life

Tryptophan Became Part Of The Universal Genetic Code Post-LUCA

by Keith CowingJuly 23, 2026July 23, 2026

[biorxiv.org] We evaluate whether tryptophan (W), widely thought to be the last of the 20 canonical amino acids added to the genetic code, was already present in the Last Universal […]

Relationships between amino acid composition, physicochemical properties, and proteome elemental composition across cellular and viral life. (A) Heatmap showing Spearman rank correlations (ρ) between amino acid frequencies and normalized elemental composition for carbon (C), hydrogen (H), nitrogen (N), oxygen (O), sulfur (S), and selenium (Se) across cellular domains and viral realms. Amino acids are shown on the yaxis using standard three and one-letter abbreviations. (B) Heatmap showing Spearman correlations between aggregated amino acid physicochemical property classes and elemental composition across the same groups. Properties include aliphatic, aromatic, non-polar, polar, charged, basic, and acidic residues. Colors indicate correlation strength and direction from negative (yellow) to positive (blue), with gray cells indicating absent values. -- q-bio.PE

Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Origin & Evolution of Life, Status Report

Deep-time Consistency In Proteome Elemental Composition Across Cellular And Viral Life

by Keith CowingMay 27, 2026May 27, 2026

Proteins are constructed from a limited alphabet of ~20 amino acids, yet the origins and selection of this specific alphabet are unresolved.

Bacteria

Dispersal of Bacterial Spores Away From Spacecraft on the Martian Surface is Unlikely to Contaminate Subsequent Life-detection Samples

Carotenoid-producing Bacteria from the Aphotic Zones of Morca Cave (Türkiye) and the Cave’s Relevance as a Terrestrial Analogue for Subsurface Astrobiology

Protocells Reproduce Morphological And Chemical Signatures Of Early Microfossils

Whole-Genome Metagenomics Insights Revealed a Uranium Bio-remediating Cross-Domain Microbiome in the Dhala Impact Structure, India

Virus-integrated Laboratory Models For Habitability Studies Of Enceladus, Europa, And Titan

Viruses, Proviruses and Satellites from Asgard Archaea Enrichments Reveal Complex Microbial Interactions

Two Origins Of Life

Bacteria That Convert Uranium Into A Stable Chemical Compound

Tryptophan Became Part Of The Universal Genetic Code Post-LUCA

Deep-time Consistency In Proteome Elemental Composition Across Cellular And Viral Life

Astrobiologist Dale Andersen’s Antarctic Field Report: 11 November 2026: Weather Update And Forecast

Astrobiologist Dale Andersen’s Antarctic Field Report: 10 November 2026: Weather Update Forecast

Dispersal of Bacterial Spores Away From Spacecraft on the Martian Surface is Unlikely to Contaminate Subsequent Life-detection Samples

From Exo-Earth Detection to Atmospheric Characterization: Enabling Phase-Dependent Molecular Detection SNR in EXOSIMS

Ancient Rocks Reveal When Earth’s Tectonic Engine Switched On