This thesis is part of the project EXTREMOON - Investigating the responses of terrestrial EXTREmophiles and their molecules in MOON environment - submitted by the research group where I did my internship and five other Italian institutions in response to the “Reserve Pool of Science Activities for the Moon: A SciSpacE Announcement of Opportunity” call for proposals and positively selected by the European Space Agency (ESA) for an upcoming mission. EXTREMOON aims to investigate the responses of extremophilic terrestrial organisms to the environment of our satellite, the Moon. Specifically, the project has proposed to use selected species of cyanobacteria, bacteria, lichens and fungi that will be dehydrated on the ground, placed in specially designed miniphotobioreactors, transported to the lunar surface and rehydrated there to assess their ability to resume metabolic activities and evaluate the effect of environmental radiation on their viability. Through spectroscopic approaches (optical density measurements and fluorescence analyses) the response to space conditions will be investigated, answering one of the questions of lunar science, namely, understanding the sensitivity of organisms to travel from Earth to the Moon and exposure to this new type of environment. My work is part of a preliminary phase of selecting species of cyanobacteria that can withstand the conditions of dehydration, shipping, transport and reactivation on this new hostile environment characterized by reduced gravity and high radiation. Among the various organisms selected, of particular interest are cyanobacteria, the first to have evolved oxygen on our planet, which are extremely plastic in terms of morphology, metabolism and photosynthesis, enough to tolerate environments where temperature, light, water, carbon dioxide can be beyond the limits of survival for most living organisms. In addition, there are strains known to the scientific community to perform different types of photoacclimation, including Far-Red light acclimation that allows them to perform oxygenic photosynthesis in both low light and Far-Red light, using chlorophyll d and chlorophyll f, pigments that absorb wavelengths in the Far-Red. The characteristics of Chlorogloeopsis fritschii, already known for its incredible physiological plasticity, adaptability to different extreme environments (flooded fields, salty and dry deserts, biofilms in hot springs) and the ability to synthesize anti-UV secondary metabolites (shinorine) led us to consider it suitable to achieve the set goals. During my internship, I tested the resistance of this cyanobacterium to dehydration and the recovery of its metabolic activity and growth capabilities after rehydration. These results have provided insight into how the recovery of cyanobacteria viability once on the Moon can be detected in a very simple way, giving guidance to the designers of the mini-photobioreactor system on suitable timing and detectors. In parallel with these experiments, cultures of C. fritschii were subjected to simulated lunar ionising radiation with neutrons of 252 Cf for six months. These cultures appear to survive and grow, although more targeted analyses will be carried out in the near future to confirm this. To evaluate these aspects, I used cultures of C. fritschii preacclimated to a Far-Red light spectrum and thus characterized by a specific photosynthetic apparatus and pigment composition. Spectroscopic, chromatographic and imaging analyses verified the rearrangement of the photosynthetic apparatus and the resumption of growth during rehydration carried out in white light.
Questa tesi si inserisce nel progetto EXTREMOON - Investigating the responses of terrestrial EXTREmophiles and their molecules in MOON environment - presentato dal gruppo di ricerca in cui ho svolto il mio tirocinio e da altri cinque enti italiani in risposta al bando “Reserve Pool of Science Activities for the Moon: A SciSpacE Announcement of Opportunity” e selezionato positivamente dall’Agenzia Spaziale Europea (ESA) per una prossima missione. EXTREMOON si prefigge di indagare le risposte di organismi terrestri estremofili all’ambiente del nostro unico satellite, la Luna. In particolare, il progetto ha proposto di utilizzare specie selezionate di cianobatteri, batteri, licheni e funghi che saranno disidratati a terra, inseriti in speciali minifotobioreattori appositamente progettati, trasportati sulla superficie lunare e lì reidratati per valutarne la capacità di ripresa delle attività metaboliche e l’effetto delle radiazioni ambientali sulla loro vitalità. Tramite approcci spettroscopici (misure di densità ottica e analisi di fluorescenza) si indagheranno le risposte alle condizioni spaziali rispondendo ad una delle questioni della scienza lunare, ovvero comprendere la sensibilità degli organismi al viaggio dalla Terra verso la Luna e l’esposizione a questo nuovo tipo di ambiente. Il mio lavoro fa parte di una fase preliminare di selezione di specie di cianobatteri in grado di resistere alle condizioni di disidratazione, spedizione, trasporto e riattivazione in questo nuovo ambiente ostile, caratterizzato da ridotta gravità e radiazioni elevate. Tra i vari organismi selezionati, di particolar interesse sono i cianobatteri, primi ad evolvere l’ossigeno nel nostro pianeta, estremamente plastici in termini morfologici, metabolici e fotosintetici tanto da tollerare ambienti dove temperatura, luce, acqua e anidride carbonica possono essere oltre i limiti della sopravvivenza per la gran parte degli organismi viventi. Inoltre, esistono ceppi noti alla comunità scientifica per eseguire diversi tipi di fotoacclimatazione, tra cui quella alla luce Far-Red che permette di effettuare fotosintesi ossigenica sia in bassa luce che in luce Far-Red, utilizzando clorofilla d e clorofilla f, pigmenti che assorbono lunghezze d’onda nel rosso lontano. Le caratteristiche di Chlorogloeopsis fritschii, già conosciuto per la sua incredibile plasticità fisiologica, adattabilità a diversi ambienti estremi (campi allagati, deserti salati e secchi, biofilm in sorgenti termali) e la capacità di sintesi di metaboliti secondari anti UV (shinorine) ci hanno portato a consideralo idoneo a raggiungere gli obiettivi prefissati. Durante il mio tirocinio ho testato la resistenza di questo cianobatterio alla disidratazione e il recupero delle sue capacità di attività metabolica e di crescita dopo reidratazione. Questi risultati hanno permesso di capire come si potrà rilevare in modo molto semplice la ripresa di vitalità del cianobatterio una volta sulla Luna dando indicazioni ai progettisti del sistema di minifotobioreattori su tempi e detectors adatti. Parallelamente a questi esperimenti, colture di C. fritschii sono state sottoposte a radiazioni ionizzanti lunari simulate con neutroni di 252 Cf per sei mesi. Queste colture sembrano sopravvivere e crescere anche se prossimamente analisi più mirate verranno effettuate per confermare ciò. Per valutare questi aspetti ho utilizzato colture di C. fritschii preacclimatate a uno spettro di luce Far-Red e quindi caratterizzate da uno specifico apparato fotosintetico e composizione in pigmenti. Analisi spettroscopiche, cromatografiche e di imaging hanno permesso di verificare il riassetto dell’apparato fotosintetico e la ripresa della crescita durante la reidratazione svolta in luce bianca.
Risposte di Chlorogloeopsis fritschii in esperimenti a terra preliminari per la missione Extremoon
CONTARIN, SAMUELE
2023/2024
Abstract
This thesis is part of the project EXTREMOON - Investigating the responses of terrestrial EXTREmophiles and their molecules in MOON environment - submitted by the research group where I did my internship and five other Italian institutions in response to the “Reserve Pool of Science Activities for the Moon: A SciSpacE Announcement of Opportunity” call for proposals and positively selected by the European Space Agency (ESA) for an upcoming mission. EXTREMOON aims to investigate the responses of extremophilic terrestrial organisms to the environment of our satellite, the Moon. Specifically, the project has proposed to use selected species of cyanobacteria, bacteria, lichens and fungi that will be dehydrated on the ground, placed in specially designed miniphotobioreactors, transported to the lunar surface and rehydrated there to assess their ability to resume metabolic activities and evaluate the effect of environmental radiation on their viability. Through spectroscopic approaches (optical density measurements and fluorescence analyses) the response to space conditions will be investigated, answering one of the questions of lunar science, namely, understanding the sensitivity of organisms to travel from Earth to the Moon and exposure to this new type of environment. My work is part of a preliminary phase of selecting species of cyanobacteria that can withstand the conditions of dehydration, shipping, transport and reactivation on this new hostile environment characterized by reduced gravity and high radiation. Among the various organisms selected, of particular interest are cyanobacteria, the first to have evolved oxygen on our planet, which are extremely plastic in terms of morphology, metabolism and photosynthesis, enough to tolerate environments where temperature, light, water, carbon dioxide can be beyond the limits of survival for most living organisms. In addition, there are strains known to the scientific community to perform different types of photoacclimation, including Far-Red light acclimation that allows them to perform oxygenic photosynthesis in both low light and Far-Red light, using chlorophyll d and chlorophyll f, pigments that absorb wavelengths in the Far-Red. The characteristics of Chlorogloeopsis fritschii, already known for its incredible physiological plasticity, adaptability to different extreme environments (flooded fields, salty and dry deserts, biofilms in hot springs) and the ability to synthesize anti-UV secondary metabolites (shinorine) led us to consider it suitable to achieve the set goals. During my internship, I tested the resistance of this cyanobacterium to dehydration and the recovery of its metabolic activity and growth capabilities after rehydration. These results have provided insight into how the recovery of cyanobacteria viability once on the Moon can be detected in a very simple way, giving guidance to the designers of the mini-photobioreactor system on suitable timing and detectors. In parallel with these experiments, cultures of C. fritschii were subjected to simulated lunar ionising radiation with neutrons of 252 Cf for six months. These cultures appear to survive and grow, although more targeted analyses will be carried out in the near future to confirm this. To evaluate these aspects, I used cultures of C. fritschii preacclimated to a Far-Red light spectrum and thus characterized by a specific photosynthetic apparatus and pigment composition. Spectroscopic, chromatographic and imaging analyses verified the rearrangement of the photosynthetic apparatus and the resumption of growth during rehydration carried out in white light.| File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/77496