Anaerobic Techniques for the Cultivation of Novel Microbes

Description

Introduction: The human microbiome encompasses a vast array of bacteria, numbering in the trillions, which intricately contribute to essential human physiological functions such as immunity, digestion, and metabolism. Advanced sequencing techniques and innovative “-omics" approaches have substantially expanded our understanding of these bacterial communities. Despite these advancements, an overwhelming 99% of microbes remain uncultivated and therefore pose an untapped resource for identifying both targets for disease prevention and mechanisms for promoting health. Many microorganisms in the human body grow anaerobically and syntrophically, evading traditional cultivation techniques. To recover these previously unknown microbes, we have developed specialized techniques to replicate in vivo conditions, including systems based on low partial pressure and anaerobic respiration, where energy is gained via electron transfer rather than carbohydrate fermentation.

Methods: In the laboratory, we have constructed a gassing manifold that allows for the selection of gaseous substrates to purge oxygen from culture vessels. Features such as pressure-control and the ability to vacuum headspace of sealed tubes provide a controlled means of making anoxic micro-atmospheres for growth. Pure cultures are obtained using a roll tube device engineered to spin Balch tubes while agar solidifies along the inner walls, creating an anaerobic petri dish-like surface for colony formation. Finally, a vinyl anaerobic chamber filled with N2, CO2, and H2 functions as a workspace free of oxygen for all subsequent experimentation.

Results: These efforts have led to the discovery of several novel taxa isolated from vole caecum, including two candidate families and a new species of Lactobacillus. 16S rRNA gene sequencing of one such isolate, Erysipelotrichaceae sp. OSU-370, revealed low nucleotide similarities with any previously described bacteria, matching only 89% with its nearest phylogenetic neighbor, Dubosiella newyorkensis. Based on preliminary in silico data from genome-mining, combined with evidence from previous microbiome studies which implicated members of this clade as beneficial modulators of human health, we hypothesize that this novel organism is involved in cognitive protection, increased longevity, and improved liver function.

Conclusions: Future work will focus on the polyphasic characterization of isolated OSU-370 and evaluating its therapeutic potential in promoting healthy aging using animal models. Finally, further use of advanced anaerobic methodologies will be instrumental for uncovering additional key contributors in the host-microbe dialogue that can be harnessed for precision medicine of the future.

Period	15 Feb 2024
Event title	Oklahoma State University Center for Health Sciences Research Week 2024
Event type	Conference
Location	Tulsa, United States, OklahomaShow on map
Degree of Recognition	Regional