Genome sequence of Christensenella minuta DSM 22607T

Obesity influences and is influenced by the human gut microbiome. Here, we present the genome of Christensenella minuta, a highly heritable bacterial species which has been found to be strongly associated with obesity through an unknown biological mechanism. This novel genome provides a valuable resource for future obesity therapeutic studies

Ionic strength is a barrier to the habitability of Mars

The thermodynamic availability of water (water activity) strictly limits microbial propagation on Earth, particularly in hypersaline environments. A considerable body of evidence indicates the existence of hypersaline surface waters throughout the history of Mars, therefore it is assumed that, as on Earth, water activity is a major limiting factor for martian habitability. However, the differing geologic histories of the Earth and Mars have driven variations in their respective aqueous geochemistry, with as-yet-unknown implications for habitability. Using a microbial community enrichment approach, we investigated microbial habitability for a suite of simulated martian brines. Whilst the habitability of some martian brines was consistent with predictions made from water activity, others were uninhabitable even when the water activity was biologically permissive. We provide evidence that high ionic strength, driven to extremes on Mars by the ubiquitous occurrence of divalent ions, renders these environments uninhabitable despite the presence of biologically available water. These findings show how the respective geological histories of Earth and Mars, which have produced differences in the planets’ dominant water chemistries, have resulted in different physicochemical extremes which define the boundary space for microbial habitability

The behavioralist as tax collector : using natural field experiments to enhance tax compliance

This paper presents results from two large-scale natural field experiments that tested the effect of social norm messages on tax compliance. Using administrative data from more than 200,000 individuals in the United Kingdom, we show that including social norm messages in standard reminder letters increases payment rates for overdue tax. This result offers a rare example of social norm messages affecting tax compliance behavior in a real world setting. We find no evidence that loss framing is more effective than gain framing. Descriptive norms appear to be more effective than injunctive norms. Messages referring to public services or financial information also significantly increased payment rates. The field experiments accelerated the collection of tax revenue at little cost

Genomic introgression mapping of field-derived multiple-anthelmintic resistance in Teladorsagia circumcincta

Preventive chemotherapy has long been practiced against nematode parasites of livestock, leading to widespread drug resistance, and is increasingly being adopted for eradication of human parasitic nematodes even though it is similarly likely to lead to drug resistance. Given that the genetic architecture of resistance is poorly understood for any nematode, we have analyzed multidrug resistant Teladorsagia circumcincta, a major parasite of sheep, as a model for analysis of resistance selection. We introgressed a field-derived multiresistant genotype into a partially inbred susceptible genetic background (through repeated backcrossing and drug selection) and performed genome-wide scans in the backcross progeny and drug-selected F2 populations to identify the major genes responsible for the multidrug resistance. We identified variation linking candidate resistance genes to each drug class. Putative mechanisms included target site polymorphism, changes in likely regulatory regions and copy number variation in efflux transporters. This work elucidates the genetic architecture of multiple anthelmintic resistance in a parasitic nematode for the first time and establishes a framework for future studies of anthelmintic resistance in nematode parasites of humans

Ammonia or methanol would enable subsurface liquid water in the Martian South Pole

The notion of liquid water beneath the ice layer at the south polar layered deposits of Mars is an interesting possibility given the implications for astrobiology, and possible human habitation. A body of liquid water located at a depth of 1.5 km has been inferred from radar data in the South Polar Cap. However, the high temperatures that would facilitate the existence of liquid water or brine at that depth are not consistent with estimations of heat flow that are based on the lithosphere's flexure. Attempts to reconcile both issues have been inconclusive or otherwise unsuccessful. Here, we analyse the possible role of subsurface ammonia and methanol in maintaining water in a liquid state at subsurface temperatures that are compatible with the lithosphere strength. Our results indicate that the presence of these compounds at the base of the south polar layered deposits can reconcile the existence of liquid water with previous estimations of surface heat flow

The identification of small molecule inhibitors with anthelmintic activities that target conserved proteins among ruminant gastrointestinal nematodes

Gastrointestinal nematode (GIN) infections are a major concern for the ruminant industry worldwide and result in significant production losses. Naturally occurring polyparasitism and increasing drug resistance that potentiate disease outcomes are observed among the most prevalent GINs of veterinary importance. Within the five major taxonomic clades, clade Va represents a group of GINs that predominantly affect the abomasum or small intestine of ruminants. However, the development of effective broad-spectrum anthelmintics against ruminant clade Va GINs has been challenged by a lack of comprehensive druggable genome resources. Here, we first assembled draft genomes for three clade Va species

Integrity of the DNA and Cellular Ultrastructure of Cryptoendolithic Fungi in Space or Mars Conditions: A 1.5-Year Study at the International Space Station

The black fungi Cryomyces antarcticus and Cryomyces minteri are highly melanized and are resilient to cold, ultra-violet, ionizing radiation and other extreme conditions. These microorganisms were isolated from cryptoendolithic microbial communities in the McMurdo Dry Valleys (Antarctica) and studied in Low Earth Orbit (LEO), using the EXPOSE-E facility on the International Space Station (ISS). Previously, it was demonstrated that C. antarcticus and C. minteri survive the hostile conditions of space (vacuum, temperature fluctuations, and the full spectrum of extraterrestrial solar electromagnetic radiation), as well as Mars conditions that were simulated in space for a 1.5-year period. Here, we qualitatively and quantitatively characterize damage to DNA and cellular ultrastructure in desiccated cells of these two species, within the frame of the same experiment. The DNA and cells of C. antarcticus exhibited a higher resistance than those of C. minteri. This is presumably attributable to the thicker (melanized) cell wall of the former. Generally, DNA was readily detected (by PCR) regardless of exposure conditions or fungal species, but the C. minteri DNA had been more-extensively mutated. We discuss the implications for using DNA, when properly shielded, as a biosignature of recently extinct or extant life

The biology of habitat dominance; can microbes behave as weeds?

Competition between microbial species is a product of, yet can lead to a reduction in, the microbial diversity of specific habitats. Microbial habitats can resemble ecological battlefields where microbial cells struggle to dominate and/or annihilate each other and we explore the hypothesis that (like plant weeds) some microbes are genetically hard-wired to behave in a vigorous and ecologically aggressive manner. These 'microbial weeds' are able to dominate the communities that develop in fertile but uncolonized - or at least partially vacant - habitats via traits enabling them to out-grow competitors; robust tolerances to habitat-relevant stress parameters and highly efficient energy-generation systems; avoidance of or resistance to viral infection, predation and grazers; potent antimicrobial systems; and exceptional abilities to sequester and store resources. In addition, those associated with nutritionally complex habitats are extraordinarily versatile in their utilization of diverse substrates. Weed species typically deploy multiple types of antimicrobial including toxins; volatile organic compounds that act as either hydrophobic or highly chaotropic stressors; biosurfactants; organic acids; and moderately chaotropic solutes that are produced in bulk quantities (e.g. acetone, ethanol). Whereas ability to dominate communities is habitat-specific we suggest that some microbial species are archetypal weeds including generalists such as: Pichia anomala, Acinetobacter spp. and Pseudomonas putida; specialists such as Dunaliella salina, Saccharomyces cerevisiae, Lactobacillus spp. and other lactic acid bacteria; freshwater autotrophs Gonyostomum semen and Microcystis aeruginosa; obligate anaerobes such as Clostridium acetobutylicum; facultative pathogens such as Rhodotorula mucilaginosa, Pantoea ananatis and Pseudomonas aeruginosa; and other extremotolerant and extremophilic microbes such as Aspergillus spp., Salinibacter ruber and Haloquadratum walsbyi. Some microbes, such as Escherichia coli, Mycobacterium smegmatis and Pseudoxylaria spp., exhibit characteristics of both weed and non-weed species. We propose that the concept of nonweeds represents a 'dustbin' group that includes species such as Synodropsis spp., Polypaecilum pisce, Metschnikowia orientalis, Salmonella spp., and Caulobacter crescentus. We show that microbial weeds are conceptually distinct from plant weeds, microbial copiotrophs, r-strategists, and other ecophysiological groups of microorganism. Microbial weed species are unlikely to emerge from stationary-phase or other types of closed communities; it is open habitats that select for weed phenotypes. Specific characteristics that are common to diverse types of open habitat are identified, and implications of weed biology and open-habitat ecology are discussed in the context of further studies needed in the fields of environmental and applied microbiology