Impact of simulated microgravity conditions on bacterial cell-cell communication utilizing Vibrio fischeri

For bacteria to thrive in stressful environments, they must communicate with one another through Quorum Sensing (QS), or chemical signals released to the environment. QS allows bacteria to sense the environment and regulate their cell number and behavior by adjusting their gene expression. This ability is made possible by the production of small chemical molecules called autoinducers (AI). The space environment is known for being a stressful place for bacteria due to space radiation and microgravity (µG). Past research in space has shown that bacteria become more virulent and resistant to antibiotics. By learning the functionality of AIs, new methods to control bacteria outbreaks can be achieved that block these chemical signals. This research project aims to improve the understanding of bacterial QS processes to describe what types of autoinducers are synthesized under simulated µG compared to earth gravity (g). This project will utilize a microgravity analog developed in the Space Microbiology Lab at ERAU. Detecting the AIs will be completed by using genetically modified bacteria, known as “biosensors”, which will luminesce if they find autoinducers produced by the model organism (Vibrio fischeri). Three types of autoinducers (responsible for virulence-related phenotypes) will be detected utilizing this method. To detect each AI, three genetically modified non-pathogenic bacterial strains were selected. The goal of this experiment will be to observe the florescence change of the biosensors between µG and g

Effects of Long-term Exposure to Microgravity Conditions on Bacterial Communities

Bacteria exposed to the spaceflight environment have been proven to show profound phenotypic changes, including increase resistance to antibiotics, increased bacterial community formation and increased resistance to environmental stresses, just to mention a few. To more fully characterize the space-flight induced conditions, we have performed a long-term experiment consisting in monitoring growth of multiple bacterial species (Escherichia coli, Lactococcus lactis and Staphylococcus salivarious) using a 2D clinostat design that simulates microgravity conditions. All bacterial species were grown in microcosms under gravity and microgravity in an effort to simulate microbiome communities. Bacteria were collected and tested for competition studies and for multiple cell phenotypes, including cell morphology, susceptibility to chemical and physical stressors and virulence-related phenotypes such as biofilm formation and antibiotic susceptibility. Possible interactions between cells grown in the artificial microbiome will help us to understand alterations of human bacterial communities during space travel

Assessing bacterial quorum sensing through measuring bioluminescence with Vibrio fischeri exposed to simulated microgravity

Bacteria flourish in stressful environments when communicating with each other in a process known as Quorum Sensing. This process is accomplished by the production of small signaling molecules referred to as Autoinducers (AI). This communication allows the bacteria to alter their gene expression in an effort to regulate their cell number, behavior and sense the surrounding environment. The space environment provides stressful conditions for bacteria as they are exposed to radiation and microgravity (µG). Because of this, it could be possible that bacteria become more virulent and resistant to antibiotics. The purpose of this research was to expose Vibrio fischeri to simulated microgravity for its ability to produce AI and measure their quantity. The methods used include measurement of fluorescence via microbial biosensors (genetically modified microorganisms) that activate gene expression of markers once a specific autoinducer is detected, readings are recorded (using a microplate reader) and graphed. Results have demonstrated increased AI production and altered colony morphology under simulated microgravity

Plant and Microbial Interactions Under Simulated Lunar Conditions

With the increase of research on establishing a lunar base, there are many challenges faced regarding sustainable living conditions. Some limitations include the cost of long-term spaceflight due to the frequent transport of food supply to the moon. The use of in-situ resources and the recycling of biomass waste can be used for sustainable crop production to decrease the costs of long-term spaceflight and make efficient use of payloads. Lunar regolith, the moon’s soil, contains all the nutrients needed for plant growth except for nitrogen. However, biomass waste, such as organic waste, can be used as a nitrogen source and a supplement providing the lunar regolith with microbial communities to sustain plant growth. In this experiment we are investigating the effects of added microbial communities in horse manure on lunar regolith simulant for optimal plant growth. The experimental design requires the testing of protocols including a watering schedule, determining an optimal ratio of manure to lunar regolith simulant, and other appropriate growth conditions. The objective of this experiment is to analyze the microbial communities in the rhizosphere for plants in different substrates in an effort to simulate the Earth’s soil that can sustain crop production for a lunar base

Plant and Microbial Interactions Under Simulated Microgravity Conditions

With human space exploration expanding to establish bases on the Moon, there are increased challenges involved to sustain astronauts. One major limitation is the food supply, which must be constantly replaced and increases mission costs. However, with long-duration missions to the Moon, the lunar environment can provide resources that can be accessed in-situ for plant growth. Plant production in space, however, poses challenges inherent to the biological stress response imposed by factors like microgravity and radiation, as shown by multiple experiments at the ISS or in simulated space environments. At the Moon, the regolith can provide support for plant growth and serve as a substrate for the formation of soil through weathering processes and the biological influence of crops and their associated microbial communities. To aid successful plant growth, microbial communities from human waste products could be used to develop organic soils, like traditional, Earth-based farming. This project aims to understand the implications of including microbial communities, from manure, on plant growth in the lunar environment. Completing this will require the utilization of lunar regolith simulant to grow Mizuna Mustard under simulated µG conditions and to study the organic content and microbial communities in the substrate as plant matter is reincorporated through successive growth cycles. To evaluate the changes, the team will study the plants\u27 physical changes, soil composition changes, and molecular microbial profile changes. The results of this research add to the growing study of space microbial ecology and provide relevant information to future long duration space exploration missions

Assessing bacterial quorum sensing through measuring bioluminescence with Vibrio fischeri exposed to simulated microgravity

Bacteria flourish in stressful environments when communicating with each other in a process known as Quorum Sensing. This process is accomplished by the production of small signaling molecules referred to as Autoinducers (AI). This communication allows the bacteria to alter their gene expression in an effort to regulate their cell number, behavior and sense the surrounding environment. The space environment provides stressful conditions for bacteria as they are exposed to radiation and microgravity (µG). Because of this, it could be possible that bacteria become more virulent and resistant to antibiotics. The purpose of this research was to expose Vibrio fischeri to simulated microgravity for its ability to produce AI and measure their quantity. The methods used include measurement of fluorescence via microbial biosensors (genetically modified microorganisms) that activate gene expression of markers once a specific autoinducer is detected, readings are recorded (using a microplate reader) and graphed. Results have demonstrated increased AI production and altered colony morphology under simulated microgravity

Developing a Pipeline to Automate Plant Growth Measuring

Experiments following the growth of plants can suffer from inaccuracies stemming from the data collection process. Tracking this growth process manually requires a measurement tool and a systematic method to record the data throughout. However, the measured values can easily vary between observers which can cause deviations in the results. Additionally, the collection process can take up to an hour, even for small-scale experiments. To overcome this issue, images can be taken of the plants which can later be analyzed for measurements. By including an appropriate scale within the image, the pixels can be converted into distance units with more consistency and at a significant time reduction. This work aims to create a pipeline that takes experimental plant growth images, analyzes them for physical measurement characteristics, and then provides easily understandable results. More specifically, some characteristics to be assessed are plant height, leaf area, and leaf count which can then be used to estimate further variables such as photosynthetic rates and wet mass. Through this automation, future plant growth studies can be completed with more robust results and less time commitment from researchers. Initially, this work will be utilized for plant growth experiments using lunar regolith amended with manure

Towards the formation of Moon soil: Mizuna mustard (Brassica rapa var japonica) developmental impacts in simulated lunar conditions and compost supplementation

With NASA’s current plans to establish a permanent base on the Moon, it becomes vital to develop strategies for improving the life support systems through in-situ resource utilization. A key limitation of existing systems is that most food is provided through resupply missions while plant production capabilities limited in scale. Instead, Moon regolith contains many essential elements that are vital for plant growth and the remainder could be supplemented with waste products from humans or plants. Additionally, including microbial communities can aid the availability of nutrients in the substrate, similar to traditional farming practices. This work aims to identify the impacts of mixing manure with lunar regolith simulant on plant development. One experiment will utilize a 2D clinostat to study Mizuna Mustard under simulated microgravity. Alternatively, another experiment will reincorporate inedible biomass from Mizuna in standard gravity conditions over successive growth cycles to identify the potential of forming Moon-based soil. Changes in microbial communities and their effect on plant growth will be evaluated via measuring the plants\u27 physical characteristics, soil composition, and molecular microbial profile. These results will add to the growing study of space microbial ecology and provide relevant knowledge for future missions to the Moon and beyond