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Biomedical subjects

Dimitri V Meier

Publications and source records attributed to Dimitri V Meier.

2 recordsLinked to original sources

Parental niche construction buffers microbial and competitive challenges and drives offspring dependence in burying beetles.

Parents across diverse taxa modify the biotic or abiotic environments of their offspring. Such modifications may constitute ecological inheritance and are central to developmental niche construction, whereby organisms shape developmental conditions and selective pressures experienced by the next generation. Despite its theoretical importance, parental niche construction is often studied under simplified conditions or by focusing on single components of care, limiting our understanding of how multiple parental modifications interact in ecologically relevant contexts, whether they buffer environmental heterogeneity, and how this shapes offspring development and evolutionary trajectories. Using the burying beetle Nicrophorus vespilloides, we investigated how parents jointly modify chemical and microbial properties of vertebrate carcasses, a highly contested resource on which offspring develop. We show that under natural microbial and competitive conditions, prehatch care enhances larval survival and growth, alters cadaveric volatile emissions, and reduces carcass attractiveness to competitors. While soil type shapes carcass-associated microbial communities, parental care buffers these environmental effects, creating a more consistent microbiome and reducing environmentally induced larval mortality. Larvae of the related species Ptomascopus morio, which lacks prehatch carcass preparation, survived equally well on prepared and unmodified carcasses, whereas N. vespilloides larvae showed reduced survival on unmodified carcasses. This contrast is consistent with the hypothesis that N. vespilloides larvae have evolved a reliance on a parentally constructed developmental environment. Together, these findings show that parental care can constitute an integrated form of niche construction that reshapes developmental environments, enhances offspring performance, and may promote evolutionary feedback leading to increased offspring dependence on parental care.

Animals

Sulfide-oxidizing potential and hypersalinity tolerance strategies in salt-crust covered coastal microbial mats.

Hypersaline microbial mats are dense microbial ecosystems capable of performing nearly complete element cycling under harsh conditions including near-saturation salinity. Our previous study of salt-crust-covered microbial mats showed that oxygenic photosynthesis was inhibited at salt saturation, while phototrophic sulfide oxidation persisted despite well-known sulfide-oxidizing taxa being undetectable. In this study, we analyzed metagenome-assembled genomes (MAGs) from the same mats to identify sulfide-oxidizing taxa and adaptations enabling oxygenic phototrophs to survive salt saturation. We extended the dataset by including morphologically identical mats exposed to lower salinity regimes to identify metabolic capabilities specifically selected for by saturation-level salinity. The phototrophic sulfide oxidation capability was found in nearly all cyanobacterial MAGs, in some Chloroflexota, and in abundant Rhodovibrio populations previously not known to oxidize sulfide. Furthermore, we found clear indications of Haloarchaea-like potassium-based osmoregulation in Bradymonadaceae (Myxococcota) adding another taxon to the few known potassium-accumulating bacteria. Despite lower oxygen concentrations, salt-crust-covered mats showed smaller proportions of fermenters and higher proportions of aerobic microorganisms than lower-salinity mats. We compared the genetic signatures of hypersalinity and desiccation tolerance in cyanobacterial MAGs from this study to genomes from desiccation-prone environments such as desert soils and small freshwater streams. Genomes of hyperhalophilic cyanobacteria were characterized by lack of certain potassium transporters and catalase genes and presence of additional osmolyte transporter subunits and sulfide-oxidation genes. We hypothesize that during salt saturation the oxidative stress for mat dwelling cyanobacteria is lowered, while the ability to oxidize sulfide provides them with energy when oxygenic photosynthesis is inhibited.

Oxidation-Reduction