Physiological and Phylogenetic Studies of the Biogeography of Alkaliphilic Heterotrophic Bacteria from Serpentinizing Habitats
Notice bibliographique
Résumé
Serpentinization occurs when ultramafic rocks containing the mineral olivine react with water to produce highly reducing conditions, which are commonly coincident with high concentrations of hydrogen. Hydrogen provides an energy source for microbial metabolism and in combination with mineral catalysts can lead to the abiogenic synthesis of small organic compounds, such as methane. Serpentinite habitats contain abundant potential electron donors, but microorganisms presumably have limited accessibility to electron acceptors. A consequence of serpentinization is the production of highly alkaline (pH 10-12), highly reducing fluids. The stress exerted on microorganisms in such ecosystems can make fundamental cellular processes such as maintaining a proton motive force or stabilizing RNA a difficult task and limit microbial diversity in these environments. It is reputed that the microbial communities in these extreme habitats are able to adjust to the ultrabasic conditions through biochemical and metabolic adaptations. However, it remains to be discovered how microorganisms have physiologically adapted to the serpentinite environment. Taxonomic characterization of novel isolates from different serpentinite habitats allows us to examine microbial biodiversity and assess whether certain microorganisms are found only at a particular site or whether their occurrence is widespread and correlated with specific environmental conditions. Comparisons of microbial diversity of the numerous serpentine sites our laboratory group is working on in the United States, Canada, and Italy to previously published studies provides insight into the biogeography of alkaliphiles in serpentinizing habitats at a global scale. Detailed physiological studies focused upon a high-resolution environmental data set from the Coast Range Ophiolite Microbial Observatory (CROMO) site in California have been used to relate physiological data from a subset of new isolates to environmental characteristics of the environments from which they were sampled. Alkaliphilic microorganisms were isolated and grown aerobically from samples collected from three different serpentinite habits located in California, Italy, and Canada between 2009 and 2013. Total genomic DNA from the isolates was used to sequence their 16S rRNA gene to establish the taxa present in each serpentinite habitat as well as in "background" soils and water. Culture-dependent analyses on a subset of isolates investigated the physiology of the isolated alkaliphilic heterotrophs. This research contributes to our understanding of microbial life in ultrabasic habitats associated with serpentinization, explores the biodiversity of the subsurface microorganisms, and characterizes their physiological adaptations.
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Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,002 | 0,003 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,002 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; les deux têtes enseignantes s’accordent sur ce qui est montré ici.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».