Electron Acceptors Influence Protist Growth Dynamics In An Anaerobic Microbial Consortium
(2023) BIOM02 20232Degree Projects in Biology
- Abstract
- Breviates are free-living, heterotrophic, anaerobic or microaerophilic amoeboflagellate protists, closely related to Opisthokonta. They possess hydrogenosomes, a subtype of anaerobically functioning, hydrogen-producing mitochondrion-related organelle, and the breviate Lenisia limosa has been reported to facultatively establish hydrogenotrophic syntrophy with Arcobacter. We believe that the interaction might be widespread across the breviate clade, and that Breviatea:Acobacteraceae consortia are potential models for the study of the establishment, evolution, and implications of H2-based syntrophy. Here, we investigate the possibility of a syntrophic interaction between an undescribed breviate strain and members of the Arcobacteraceae.... (More)
- Breviates are free-living, heterotrophic, anaerobic or microaerophilic amoeboflagellate protists, closely related to Opisthokonta. They possess hydrogenosomes, a subtype of anaerobically functioning, hydrogen-producing mitochondrion-related organelle, and the breviate Lenisia limosa has been reported to facultatively establish hydrogenotrophic syntrophy with Arcobacter. We believe that the interaction might be widespread across the breviate clade, and that Breviatea:Acobacteraceae consortia are potential models for the study of the establishment, evolution, and implications of H2-based syntrophy. Here, we investigate the possibility of a syntrophic interaction between an undescribed breviate strain and members of the Arcobacteraceae. Breviates were grown in microcosms containing multiple prokaryotes in complete anoxia and with and initial supply of oxygen, and supplemented with KNO3 and N2O that might serve as electron acceptors for H2 consumption by the alleged bacterial partner. Bayesian statistical modelling was used to assess the growth dynamics of the breviate. We found air to significantly stimulate breviate replication within the assessed timeframe, while KNO3 inhibited growth at the tested concentration. Our work highlights the need for further characterization of breviate growth dynamics and for optimization of culturing methods and provides preliminary information to guide future research. Additionally, we designed four pairs of primers for quantitative polymerase chain reaction (qPCR) and optimized one pair up to 94%. In future work, qPCR could be used in the microcosm to identify mutualistic population dynamic patterns between the breviate and selected prokaryote strains. (Less)
- Popular Abstract
- Divide and conquer
Partnership as a means of thriving in hostile environments
Breviates are free-living protists (i.e., single-celled eukaryotes), closely related to animals and fungi, that thrive in environments with little or no oxygen. Instead of the classical mitochondria, which use oxygen to produce ATP (the main energy bar of the cell), breviates possess a subtype of mitochondrion-related organelles called hydrogenosomes. Hydrogenosomes yield energy independently of oxygen and produce molecular hydrogen (H2) in the process. This process is more efficient if H2 is removed from the environment, which several prokaryotes eagerly do to feed their own energy metabolism. This leads to the establishment of a metabolic partnership called... (More) - Divide and conquer
Partnership as a means of thriving in hostile environments
Breviates are free-living protists (i.e., single-celled eukaryotes), closely related to animals and fungi, that thrive in environments with little or no oxygen. Instead of the classical mitochondria, which use oxygen to produce ATP (the main energy bar of the cell), breviates possess a subtype of mitochondrion-related organelles called hydrogenosomes. Hydrogenosomes yield energy independently of oxygen and produce molecular hydrogen (H2) in the process. This process is more efficient if H2 is removed from the environment, which several prokaryotes eagerly do to feed their own energy metabolism. This leads to the establishment of a metabolic partnership called H2-based syntrophy. Syntrophy is a relevant process in anaerobic environments that can have implications for greenhouse gas emissions, nutrient cycling in ecosystems, research on the origin and evolution of eukaryotes, and technical and industrial processes.
H2-syntrophy has been described between a breviate species and a bacterial group called Arcobacteraceae. We believe that this interaction is widespread across the breviates and that breviates can be useful models to better understand syntrophy. In this degree project, we investigate the possibility of a metabolic cooperation between a previously undescribed breviate and bacterial strains. We do that by adding compounds that can stimulate H2 consumption by the Arcobacteraceae, and assessing if the growth of the breviate is enhanced by doing so.
We have found that breviates replicate faster when a low amount of oxygen is present, compared to when the environment is completely oxygen-free. As far as we know, breviates don’t have the ability to use oxygen and are rather sensitive to it. Therefore, we interpret that the benefits of oxygen for protist growth are mediated by a bacterial symbiont. We also found that nitrate potassium (KNO3), which we expected to have a positive effect on the breviates, instead inhibited their growth. The concentration of KNO3 might have been too high, and further research should be done to assess if that is the case. Moreover, we detected issues with the culturing conditions that manifested as very low growth rates, indicating that optimization of the culturing methods for the breviate is needed. Additionally, we took first steps in the development of a molecular method (based in quantitative polymerase chain reaction) that can be used in the future to identify mutualistic population dynamics in breviate cultures.
Overall, this project identifies knowledge gaps in the assessment of syntrophy in breviates and provides preliminary information to guide future research.
Master’s Degree Project in Biology 30 credits 2023
Department of Biology, Lund University
Advisor: Courtney Stairs (main); Karla Iveth Aguilera Campos
Advisors Unit: Molecular Cell Biology Unit (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9145083
- author
- Behncké Serra, Ada
- supervisor
- organization
- course
- BIOM02 20232
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9145083
- date added to LUP
- 2024-01-15 16:37:43
- date last changed
- 2024-01-15 16:37:43
@misc{9145083,
abstract = {{Breviates are free-living, heterotrophic, anaerobic or microaerophilic amoeboflagellate protists, closely related to Opisthokonta. They possess hydrogenosomes, a subtype of anaerobically functioning, hydrogen-producing mitochondrion-related organelle, and the breviate Lenisia limosa has been reported to facultatively establish hydrogenotrophic syntrophy with Arcobacter. We believe that the interaction might be widespread across the breviate clade, and that Breviatea:Acobacteraceae consortia are potential models for the study of the establishment, evolution, and implications of H2-based syntrophy. Here, we investigate the possibility of a syntrophic interaction between an undescribed breviate strain and members of the Arcobacteraceae. Breviates were grown in microcosms containing multiple prokaryotes in complete anoxia and with and initial supply of oxygen, and supplemented with KNO3 and N2O that might serve as electron acceptors for H2 consumption by the alleged bacterial partner. Bayesian statistical modelling was used to assess the growth dynamics of the breviate. We found air to significantly stimulate breviate replication within the assessed timeframe, while KNO3 inhibited growth at the tested concentration. Our work highlights the need for further characterization of breviate growth dynamics and for optimization of culturing methods and provides preliminary information to guide future research. Additionally, we designed four pairs of primers for quantitative polymerase chain reaction (qPCR) and optimized one pair up to 94%. In future work, qPCR could be used in the microcosm to identify mutualistic population dynamic patterns between the breviate and selected prokaryote strains.}},
author = {{Behncké Serra, Ada}},
language = {{eng}},
note = {{Student Paper}},
title = {{Electron Acceptors Influence Protist Growth Dynamics In An Anaerobic Microbial Consortium}},
year = {{2023}},
}