Our lab has found a novel behavior in Chlamydomonas reinhardtii which seems to be a quorum sensing response where the growth and increase in cell density of C. reinhardtii causes an increase in the swim speed of the population. We are trying to understand how this system works within the lab strain cc124 and other related strains and species of Chlamydomonii as well as trying to identify the exact molecule responsible for this effect. This larger project has a number of side projects such quorum quenching effects on the AHLs of some bacteria species (Ryan Quick).
Bacteria possess the ability to communicate with one another and initiate phenotypic changes through a phenomenon known as quorum sensing. This process is regulated by autoinducer molecules that are produced in proportion to cell density. Gram-negative bacteria use an autoinducer species known as N-acyl-L-homoserine lactones (AHLs). Previous studies of model plants have shown that AHLs influence the growth of plants when they are accessible as a nutrient source. This project will focus on how the unicellular plant-like algae Chlamydomonas reinhardtii metabolically incorporates these signals and compare its similarity to previously studied model organisms (Adam Bach).
Cyanobacteria contain differentiating cells which perform various functions. Anabaena species produce heterocyst cells which fix nitrogen from the atmosphere into bioavailable ammonium. In lunar and Martian regolith simulants, a limiting factor to plant growth has been identified as nitrogen availability. Additionally, the acidic polysaccharide sheath produced by this genus is capable of bioleaching and releasing nutrients from regolith which are potentially beneficial to plants. In this project, the nitrogen-fixing and bioleaching performed by Anabaena cylindrica are leveraged to deposit nitrogen into extraterrestrial regolith simulants and evaluate the subsequent improvement in plant growth (Haley Murphy).
Martian Global Simulant-1 (MGS) is a high-accuracy regolith simulant produced by Space Resource Technologies (formerly Exolith Labs, University of Central Florida). Plant growth in MGS is complicated by its fine, dusty grains which compact when watered. Chemically, high salinity and alkaline pH have disrupted seed germination, preventing plant growth altogether. To identify the compounds causing this issue, we obtained the individual mineral constituents of MGS to evaluate germination and plant growth potential (Haley Murphy).
Travel to the Red Planet (Mars) has inspired researchers and dreamers for decades if not centuries. The fast-paced growth of the space sector has made this likely a reality within our lifetime with missions to Mars expected by the 2030s. A permanent settlement come within a decade after that. Some aspects of the Martian environment are still understudied, however, and pose serious dangers to the security of Mars missions no matter the duration. The presence of perchlorate salts, highly toxic oxidizing compounds found in Martian regolith, will be unavoidable on the planet’s surface. On short-term missions, there are health risks associated with even brief exposures to perchlorates, but we see the biggest detriment in the long term; with these toxic salts being globally pervasive in Martian regolith, and regolith being the most abundant Martian resource, all in situ resource utilization strategies (ISRUS), particularly those involving the growth of crops or useful bacteria, fall apart. We cannot make use of Martian regolith without perchlorate removal methods, especially when discussing regolith-based agriculture (RBA). In this study, we have evaluated the growth of millet crop plants in Martian regolith simulants treated with a microbial consortium to eliminate perchlorates, introduced at Mars-relevant concentrations. This proof-of-concept study begins to fill this significant knowledge gap that is mission critical to a future Martian settlement (Frannie Edmonson).
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