Biology subjects

Reitzel, A.

Publications and source records attributed to Reitzel, A..

3 recordsLinked to original sources

bioRxiv2018

Bacterial community dynamics during embryonic and larval development of three confamilial echinoids

Development of some animals is influenced by and, in some cases, dependent on the associated microbiota. The timing of when associated bacterial communities are established during the development of marine invertebrates and their subsequent dynamics across stages are known for only a few species. Here, we compare the bacterial communities of three confamilial echinoids from egg to juvenile using sequence-based approaches. Bacterial communities are established on unfertilized eggs and change gradually during embryonic and larval development. Despite the differences amongst these pre-metamorphic stages, approximately thirty-percent of OTUs identified in association with unfertilized egg were present in the juveniles. During embryonic development, host-associated communities diverged from the environmental microbiota but later converged following the onset of larval feeding. Taken together, the data presented here support the hypothesis that bacterial communities are established prior to fertilization and community composition shifts gradually thereafter, all while remaining distinct from the environment. Future work will need to determine the relative influence of the host and bacteria-bacteria interactions in shaping the associated bacterial community to determine the potential functional importance of bacteria during the development of larval sea urchins and benthic marine invertebrates more broadly.

developmental biology↗

bioRxiv2018

Biogeography masks diet-induced shifts in the bacterial community associated with larvae of the sea urchin Strongylocentrotus droebachiensis

Animals acclimate to changes in their environment through diverse responses, including phenotypic plasticity and shifts in their microbiome. These microbial communities are also taxonomically distinct across the geographical distribution of the host. It is less known, however, whether taxonomic differences in host-associated bacterial communities between geographically distinct populations mask shifts due to environmental changes within a population. We tested for potential ecological masking using larvae of the echinoid Strongylocentrotus droebachiensis from three coastal locations in the Pacific and Atlantic Oceans that were exposed to four feeding regimes. When considering OTU membership and the relative proportion of those taxa, the composition of the larval-associated bacterial communities were best explained by location, not feeding regime. Similarly, predicted metagenomic gene profiles from these bacterial communities were congruent with population specificity and may suggest a role in metabolism. We hypothesize that, while much of the differences in the bacterial communities is related to the large geographic distances between these locations, the predicted overlapping functions of the microbiome may relate to responding to ecological variation experienced by these larvae. Taken together, these results suggest that differences in community composition between populations masks local variation, and that scaling should be considered in when studying microbiome dynamics.

ecology↗

bioRxiv2017

A microbial perspective on the life-history evolution of marine invertebrate larvae: if, where, and when to feed

The feeding environment for planktotrophic larvae has a major impact on development and progression towards competency for metamorphosis. High phytoplankton environments that promote growth often have a greater microbial load and incidence of pathogenic microbes, while areas with lower food availability have a lower number of potential pathogens. Trade-offs between metabolic processes associated with growth and immune functionality have been described throughout the animal kingdom and may influence the life-history evolution of marine invertebrate planktotrophic larvae in these environments. Namely, to avoid potential incidences of microbial-mediated mortality and/or dysbiosis, larvae should regulate time spent between these two feeding environments. We describe here transcriptomic and microbiome data that supports this trade-off in larvae, where larvae in a well-fed environment upregulate genes associated with metabolism and may regularly enter a state of dysbiosis, resulting in mortality. To address the hypothesis that the environmental microbiota is a selective force on if, where, and when planktotrophic larvae should feed, we present a strategy for determining the specific interactions of larvae and microbes at a scale representative of their larger pelagic environment.

evolutionary biology↗