Biology subjects

Real-Ramirez, I.

Publications and source records attributed to Real-Ramirez, I..

2 recordsLinked to original sources

bioRxiv2020

High-throughput cultivation of stable, diverse, fecal-derived microbial communities to model the intestinal microbiota

SummaryMechanistic understanding of the impacts of the gut microbiota on human health has been hampered by limited throughput in animal models. To enable systematic interrogation of gut-relevant microbial communities, here we generated hundreds of in vitro communities cultured from diverse stool samples in various media. Species composition revealed stool-derived communities that are phylogenetically complex, diverse, stable, and highly reproducible. Community membership depended on both medium and initial inoculum, with certain media preserving inoculum compositions. Different inocula yielded different community compositions, indicating their potential for personalized therapeutics. Communities were robust to freezing and large-volume culturing, enabling future translational applications. Defined communities were generated from isolates and reconstituted growth and composition similar to those of communities derived from stool inocula. Finally, in vitro experiments probing the response to ciprofloxacin successfully predicted many changes observed in vivo, including the resilience and sensitivity of each Bacteroides species. Thus, stool-derived in vitro communities constitute a powerful resource for microbiota research.Competing Interest StatementThe authors have declared no competing interest.View Full Text

microbiology↗

bioRxiv2019

Insects as phyllosphere microbiome engineers: effects of aphids on a plant pathogen.

Insect herbivores are common in the phyllosphere, the above-ground parts of plants, and encounter diverse plant-associated bacteria there, yet how these organisms interact remains largely unknown. Strains of the bacterium Pseudomonas syringae grow well epiphytically and have been shown to grow within and kill hemipteran insects like the pea aphid, Acyrthosiphon pisum. Aphids are hypothesized to be an alternative host for these epiphytic bacteria but it is unclear if aphids provide fitness benefits to these bacterial pathogens. To determine if epiphytic bacteria could be adapted for infecting aphids, we characterized 21 strains of P. syringae for epiphytic ability and virulence to pea aphids and found that the two traits were positively correlated. For a subset of strains, we tested if the bacteria derived a fitness benefit from the presence of aphids. Some strains benefited significantly, with up to 18.9% higher population densities when aphids were present, and lower starting population density was predictive of higher benefit from aphid presence. However, further investigation found that honeydew, the sugary waste product of aphids, and not growth in aphids, increased P. syringae growth on leaves. This suggests that aphids may be important microbiome engineers in the phyllosphere, but evolutionarily dead-ends for epiphytic bacteria.

evolutionary biology↗