Projet de recherche PX/8/LP/15 (Action de recherche PX)
The aim of the present project is to contribute to the development of DNA methodologies for the rapid monitoring and control of yeast and yeast like fungi development in confined human made environments, and which would prove useful for the space habitat condition but that can also find interesting application on similar situation on earth. The use of DNA technologies would allow avoiding the handling of yeast strains by the crewmembers and to by-pass the morphological or physiological variations that may occur in space.
Up to now, survey and identification of fungi, including yeast, in manned spacecrafts made necessary to isolate the various species by air and surface sampling. Nevertheless, handling of micro-organisms is not recommendable in spacecrafts since, in multiplying the micro-organisms, it greatly increases the risk of accidental of release of huge quantity of spores resulting in large contamination. Furthermore, the morphology, the physiology, the growth, and the development of yeast in spacecrafts could be modified to some extend by micro-gravity. This might be especially true for the physiology, as demonstrated for bacteria, and which up to now, remained a major approach for identification. This could result in difficulties to accurately identify the yeast species, and thus to evaluate their ecology and bio-deterioration potential, in relation to bio-films development. Therefore, the development of other non-environment and non-culture dependant methods but still simple and especially rapid, are required for an optimum monitoring.
Objectives of the project
- To make a survey of the yeast and yeast like fungi present in manned spacecraft from various sources (air-conditioned system, filters, surface, …).
- To determine their relative frequency and their relevance in term of opportunist micro-organisms and of bio-deterioration agent of on-board equipment;
- To design molecular tools for the rapid and accurate detection of selected taxa chosen based on literature and “in situ” survey.
- To study the yeast populations diversity collected during space flights and to compare them with batches of strains from various terrestrial eco-geographic and environmental origins.
Methodology
1. Literature survey of microbiology in space aircraft conditions and earth similar environment.
2. Survey of levuriform fungi present in samples collected either in real manned space aircraft situation and in comparable environments such as sterile production chambers in pharmaceutical company, dust-free rooms in electronic industry, air filter, water system… Morphological and molecular identification of the different taxa isolated. The accurate identification at species or infra-specific level is necessary for the second step, but can also bring us useful information about the ecology of the various species, data that could be used later on to set up “preventive” measures.
3. Following the results of the step 2, a selection of the relevant yeast taxa to be worked out in the step 3 (detection by molecular tools, 5-10 taxa) will be done. The selection of the strains/taxa will be based on their frequency and abundance, their ecology, the background from literature and from BCCMTM /MUCL’s own experience regarding their potential impact as human opportunist, and their bio-deterioration or their adhesion properties on artificial substrates. The taxonomic level to work out (species, complex of species, genus) will also be determined according to several criteria as the purpose of their detection. For example, for chemical disinfections of spacecraft constituents, detection of yeast at generic level should be sufficient. However, detection up to the species level can be advantageous in some cases where properties are more species-specific, such as fouling agent, adhesion properties to artificial substrate, allergenic potential.
4. Design of molecular tools for the rapid and accurate detection of the selected taxa at the selected taxonomic level, using PCR, real time-quantitative PCR
5. Validation of the molecular tools by assays on various samples in laboratory conditions carried out on samples made in controlled laboratory conditions (controlled “complex” samples) and from “in situ” uncontrolled samples from “real” confined earth environment, and design of future experiment for their application for space aircraft conditions
6. Diversity studies of yeast populations from space and earth origin. This would allow to track the possible origin of yeast contaminant in spacecraft, and consequently to design better “preventive” measures that would reduce the risk of presence and further development.
Satellite(s) or flight opportunity(ies):
- TBD
Field of research:
Life Science: Biology: Cell & Developmental Biology
