EAGER: Tools4Cells: Developing robust methods for the molecular study of kelp respiration

Kelp are major components of coastal ecosystems and economies around the world. Their large contributions to carbon sequestration and the de-acidification of oceans have sparked interest in kelp-based strategies to address environmental fluctuations. However, our ability to develop sophisticated strategies is hindered by an almost complete lack of understanding of the biochemical processes that underpin kelp’s carbon metabolism: photosynthesis and respiration.

This gap is mainly driven by our inability to purify kelp’s chloroplasts and mitochondria—the cellular compartments (“organelles”) in which photosynthesis and respiration take place. Being able to isolate these organelles would allow us to perform biochemical studies to understand how the details of kelp photosynthesis and respiration and how they are different from plants and other organisms.

To close this gap, this project will develop methods to purify mitochondria from giant kelp (Macrocystis pyrifera). This will generate tools to better understand kelp’s carbon metabolism, laying the foundation to design better kelp-based strategies to address environmental fluctuations. The project’s Broader Impacts include: training the next generation of scientists, developing Macrocystis pyrifera as a new model organism for carbon metabolism, providing mentorship and research experiences for undergraduates and senior researchers, and propagating the differences between kelp and plants with the wider public.

Brown algae are major primary producers and key contributors to global carbon sequestration. Understanding the molecular details of how brown algae convert energy via photosynthesis and respiration has strong biological, ecological and economic implications. Despite this, the details of brown algae respiration and photosynthesis remain unexplored at the atomic, protein, organelle and cellular levels.

The long-term goal of the project is to uncover the molecular details of mitochondrial respiration of brown algae and understand its mechanistic differences with other photosynthetic groups. To achieve this, the first step is to isolate brown algae mitochondria and purify the respiratory complexes from them for biochemical and structural studies. However, the ability to isolate mitochondria from brown algae has remained a major technical roadblock.

This project will address this gap by developing methods to isolate Macrocystis pyrifera (giant kelp) mitochondria at an appropriate scale and purity. The investigators will test chemical, enzymatic and physical treatments for increased mitochondrial recovery. They will also explore the purification of M. pyrifera’s respiratory complexes for biochemical and structural studies by testing approaches involving vesicles derived from native mitochondrial membrane.

The methods will set the foundation to understand brown algae respiration at a level of detail (amino acid interactions) much higher than previously possible (ecology or whole-organism physiology). The work will generate mechanistic hypotheses to be tested biochemically, genetically and physiologically.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.