Senatore, Giuliana (2020) Impact of the exposure to simulated microgravity conditions on the probiotic Lactobacillus reuteri DSM 17938. [Tesi di dottorato]

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Tipologia del documento:	Tesi di dottorato
Lingua:	English
Titolo:	Impact of the exposure to simulated microgravity conditions on the probiotic Lactobacillus reuteri DSM 17938
Autori:	Autore Email Senatore, Giuliana giuliana.senatore@unina.it
Data:	12 Marzo 2020
Numero di pagine:	150
Istituzione:	Università degli Studi di Napoli Federico II
Dipartimento:	Agraria
Dottorato:	Scienze agrarie e agroalimentari
Ciclo di dottorato:	31
Coordinatore del Corso di dottorato:	nome email D'Urso, Guido durso@unina.it
Tutor:	nome email Mauriello, Gianluigi [non definito]
Data:	12 Marzo 2020
Numero di pagine:	150
Parole chiave:	simulated microgravity; MELiSSA space research programme; microbiota; probiotic bacteria; transcriptome; proteome
Settori scientifico-disciplinari del MIUR:	Area 07 - Scienze agrarie e veterinarie > AGR/16 - Microbiologia agraria
Depositato il:	20 Mar 2020 15:26
Ultima modifica:	10 Nov 2021 10:17
URI:	http://www.fedoa.unina.it/id/eprint/13050

Abstract

This PhD thesis is a part of MELiSSA (Micro Ecological Life Support System Alternative) space research program aiming to develop an artificial ecosystem for regenerative life support systems for long-term space missions. Designing an efficient life support system is needed to maintain the minimum life requirements for humans in space. For this reason, the health status of astronauts has been extensively investigated. In particular, many researches were focused on the study of astronauts’ immune system changes induced by simulated or real spaceflight conditions. On the contrary, very few investigations can be found in the literature that address the issue of the intestinal microbiota and its significant role in the astronaut’s health. Moreover, little attention has been given to the study of spaceflight effects on probiotic bacteria, that may be administered to space crew for the purpose to help and improve both innate and adaptive immune responses and in the same time prevent or reduce these effects. The principal environmental stressors of spaceflight have harsh changes in microbial response to the space environment is the microgravity. This condition could increase the pathogenicity characteristics of some microorganisms and in the presence of more resistant bacteria, the natural terrestrial diversity of the gastrointestinal microflora could be reduced. The increased pathogenicity characteristics of some microorganisms, the spacecraft environment with high bacterial contamination due to reduced ventilation and a little varied diet could cause a reduction of the number and/or diversity of beneficial bacteria and, consequently, a decline in immune responses, representing a risk to the health of astronauts, already compromised by psychological stress. This PhD thesis deals with this context treating some aspects of astronauts’ safety in the space with the aim to cultivate a probiotic bacterium in one of bioreactor of MELiSSA loop to use as a direct source of supply for the astronauts’ diet. We assessed the role of a probiotic microorganism in a simulated microgravity environment and evaluate whether this spaceflight condition affect the metabolism of this bacterium and modify its probiotic features. We focused the study on the probiotic strain Lactobacillus reuteri DSM17938, that is a principle component of some commercial products, and evaluated its transcriptome and proteome under simulated microgravity conditions to improve prediction of enzymatic pathways present in a well-defined environment. The investigations in microgravity could highlight the mechanisms of regulation and adaptation of this probiotic bacterium, which will be helpful in uncovering the interactions between this bacterium and a confined environment, including human gut.

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