The learning curve of saltwater tanks: Our group at Colorado School of Mines is new to corals and specifically how to keep them alive to do controlled experiments. We went to a local saltwater tank store that helped us with initial ideas and setup, but each tank is unique to its species and the health of that species. We quickly started adjusting salinity content and checking pH.

Unfortunately, our first coral bleached, and we thought we were able to save it. We were unsuccessful, but we gained some insight into the visible signs of health in our tank and of our coral! We now have automatic pumps and readers that keep our tank conditions ideal. We also do salinity and pH tests of our tank water each day. We now have a healthy and growing Pocillopora damicornis colony and we are successfully growing new corals with nubbins removed from the large healthy coral.

Our goal: Corals are evolutionarily early invertebrates belonging to the fascinating animals called Cnidaria. The coral holobiont is comprised of the coral animal and its 20,000 or so associated microorganisms consisting of the dinoflagellate algae Symbiodinium, bacteria, fungi, viruses and bacteriophages, archaea, and protists. The members of the coral holobiont fluctuate depending on the environmental conditions and are believed to play an important role in its health. However, “coral health” is an ill-defined term and we are working on standardizing this term and the experimental conditions under which we study it in order to have an experimental validation system for computational predictions made in our project.

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Fig.1: Image showing the time-lapse images of Pocillopora damicornis polyp bailout under salinity stress.

Key areas:

  1. Standardization of 96 well-format model system to study coral at polyp level
  2. Establishment of coral cell lines to study coral cell biology at the cellular level
  3. Decoding the chemical language of corals
  4. Quantifying markers of coral bleaching
  5. Communication amongst the 20,000 members of the microbiome

The mystery of polyp bailout: We are working as a multidisciplinary research team to answer the above questions. Currently, we have established a microtiter plate-based model system of salinity induced coral bailout process (Fig.1). Polyp bailout term was coined by Paul Sammarco in 1982. Polyp bailout is the process of detachment of polyps from the coral colony skeleton. This is a complex event and depends on the low water quality, changes in salinity, pH, and temperature. Our next objective is to make a 96 well plate model and a microfluidic platform to study individual polyps in parallel.

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Fig.2: Confocal microscopic image of Symbiodium isolated form Pocillopora damicornis polyps (stained with acridine orange and propidium iodide). Green oval structure represents live symbiodinium cells.

Social networking in corals: We have made a unique antibiotic cocktail-based cell culture media to grow Symbiodium cells (Fig.2). This may allow us to study the Symbiodium and coral interactions at the molecular level. In the future, if we can understand the molecular biology of this interaction, we may be able to use programmed algae cells as a cellular therapy to revive the bleached coral colonies.

Wound healing and tissue regeneration: Observing coral colony healing at a laboratory scale was astonishing to us (Fig.3). After coral branch clipping, the process of healing appears to start right away and the damaged area typically recovers in a few weeks! Thus, the understanding of the coral wound healing process could be a novel framework to better understand the human wound healing process.

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Fig.3: Image of coral colony showing the process of wound healing (appearance of new polyps on the damaged area within three weeks.

“Rock” characterization: Being at a school with heavy focus on earth resources that sometimes is referred to as the “Colorado School of Rocks” sometimes has advantages! Techniques used routinely at Mines for characterization of shale like T2 relaxation measurements by NMR for porosity and CT scanning for structure are directly applicable to the coral skeletons and we have some first results! It will be very exciting to study the mechanisms of skeleton growth and possibly manipulate it.

Corals are ancient animals that have evolved remarkable adaptation strategies. Understanding coral biology at the molecular and cellular levels can provide us deep insights into our understanding of this evolution process, the cellular signaling pathways of skeleton formation, wound healing and social communication with microbial partners.

Future Work and Goals:

Our team is ready to work with microfluidic devices to allow for the simulation of water flow for experiments.

We will start digging for receptor proteins with homology to human membrane receptors in the coral genome. A new form of “mining” for Colorado School of Mines!

We hope to understand all the cell types and to begin to design experiments that will provide immunological information.

We all hope to use the insight we will gain to help save the corals and possibly humans too!