We are investigating how different aquatic bacterial strains grow and interact by mixing them in various proportions and measuring their absolute abundance over time. To estimate the growth rates of individual strains and their interactions, we are using a mathematical approach based on the Lotka-Volterra model, which describes the dynamics of competing species.

Our method involves using rStan, a powerful statistical tool, to fit our data to a system of ordinary differential equations (ODEs). This allows us to accurately estimate how each bacterial strain grows and how they influence each other's growth in the mixture.

By understanding these interactions, we can gain valuable insights into the dynamics of microbial communities, which has implications for both natural ecosystems and industrial applications.

Fluorescent bacterial culture photos by Denisse Larin-Henriquez

In various ecosystems, bacteria interact with plants in complex ways, sometimes helping, sometimes harming, or having no effect at all. However, we still don't fully understand how bacteria living on leaves impact plant growth. Our research focused on the purple pitcher plant, Sarracenia purpurea, to explore this question.

We studied how different bacterial communities affect the growth and nutrient content of these plants. Previous research has shown that microbes help carnivorous plants like S. purpurea decompose prey and acquire nutrients, but the specific roles of these bacterial communities in plant growth were unclear.

To investigate, we introduced three different types of bacterial communities into newly opened pitcher plant leaves and monitored them over eight weeks. We used various techniques to measure bacterial functions and their impact on the plants. Our results showed that bacterial communities with strong decomposition abilities helped the plants grow larger leaves with almost double the biomass compared to plants without these bacteria.

We also found that the bacteria with the highest chitinase activity (an enzyme that breaks down chitin) had more genes active for chitinase production. This suggests that these bacteria directly contribute to plant growth through nutrient cycling.

Our study highlights the important role of bacterial communities in supporting plant health and growth, offering new insights into how plants and microbes work together in nature.

Check out more about this research here: https://journals.asm.org/doi/10.1128/msystems.01298-24

Microbial communities are influenced by environmental factors like temperature, pH, and nutrients. Understanding these influences helps predict ecological responses to changes. We studied aquatic bacterial communities from the carnivorous pitcher plant, Sarracenia purpurea, in the lab. Our findings show that changes in pH, temperature, and nutrient levels can significantly impact these communities. For example, high temperatures and low pH altered bacterial composition and reduced community function. We found that certain bacteria, like Acinetobacter, directly affect enzyme activities, impacting how these communities process nutrients. These results emphasize the need to consider multiple environmental factors together to predict ecological outcomes accurately.

https://onlinelibrary.wiley.com/doi/10.1111/mec.70102?af=R

Microbial communities play a key role in breaking down organic material and recycling nutrients in ecosystems. While we know a lot about how leaf litter decomposes, less is understood about the decomposition of insect remains. In our study, we investigated how different types of insect prey affect microbial activity in the carnivorous pitcher plant, Sarracenia purpurea.

We placed different insects (ants, beetles, and flies) in sterile mesh bags and observed decomposition over seven weeks. Our results showed that insects with tougher exoskeletons, like ants and beetles, decomposed more slowly than softer insects like flies. The fly treatment had the highest protease enzyme activity, aiding faster decomposition.

Additionally, ant remains lowered the pH of the pitcher fluid, influencing microbial activity. Treatments with the highest bacterial diversity, such as ants and beetles, were linked to slower decomposition rates.

Overall, our research highlights that different insect prey provide unique nutrients to microbial communities, affecting their composition and enzyme activity.

Check out more about this research here: https://journals.asm.org/doi/full/10.1128/aem.00394-24

Ascomycete fungi, traditionally classified by their physical characteristics, sometimes show inconsistencies when modern DNA analysis is applied. Our study focused on the fungus Robergea albicedrae, which grows exclusively on the Ashe juniper tree.

First described in 1910, Robergea albicedrae has undergone several reclassifications. We aimed to provide new insights into its life cycle and genetic relationships. To do this, we cultured the fungus, observing its growth over 17 months. Additionally, we sequenced its DNA to analyze its genetic placement.

Our results confirmed that Robergea albicedrae belongs to the order Ostropales and the family Stictidaceae within the class Lecanoromycetes. This study enhances our understanding of this unique fungus and supports its current classification.

Additionally, we were able to culture a wide diversity of fungi associated with Ashe juniper bark. Overall, we isolated 67 fungal cutures, representing 17 unique genera.