Biology subjects

Ferrari, B. C.

Publications and source records attributed to Ferrari, B. C..

2 recordsLinked to original sources

bioRxiv2019

Novel Quorum Sensing Activity in East Antarctic Soil Bacteria

Antarctica, being the coldest, driest and windiest continent on Earth, represents the most extreme environment a living organism can thrive in. Under constant exposure to harsh environmental threats, terrestrial Antarctica remains home to a great diversity of microorganisms, indicating that the soil bacteria must have adapted a range of survival strategies that require cell-to-cell communication. Survival strategies include secondary metabolite production, biofilm formation, bioluminescence, symbiosis, conjugation, sporulation and motility, all of which are often regulated by quorum sensing (QS), a type of bacterial communication. Up to now, such mechanisms have not been explored in terrestrial Antarctica. Here, for the first time, LuxI/LuxR-based quorum sensing (QS) activity was delineated in soil bacterial isolates recovered from Adams Flat, in the Vestfold Hills region of East Antarctica. Interestingly, we identified the production of potential homoserine lactones (HSLs) ranging from medium to long chain length in 19 bacterial species using three biosensors, namely Agrobacterium tumefaciens NTL4, Chromobacterium violaceum CV026 and Escherichia coli MT102, in conjunction with thin layer chromatography (TLC). The majority of detectable HSLs were from gram-positive microorganisms not previously known to produce HSLs. This discovery further expands our understand of the microbial community capable of this type of communication, as well as providing insights into physiological adaptations of microorganisms that allow them to survive in the harsh Antarctic environment.\n\nIMPORTANCEQuorum sensing, a type of bacterial communication, is widely known to regulate many processes including those that confer survival advantage. However, little is known about communication by bacteria thriving within Antarctic soils. Employing a combination of bacteria biosensors, analytical techniques, and genome mining, we found a variety of Antarctic soil bacteria speaking a common language, via the LuxI/LuxR-based quorum sensing, thus potentially supporting survival in a mixed microbial community. This is the first report of quorum sensing activity in Antarctic soils and has provided a platform for studying physiological adaptations of microorganisms that allow them to not just survive but thrive in the harsh Antarctic environment.

microbiology↗

bioRxiv2019

Extreme niche partitioning promotes a remarkably high diversity of soil microbiomes across eastern Antarctica.

Terrestrial Antarctica, a predominantly microbial realm, encompasses some of the most unique environments on Earth where resident soil microbiota play key roles in the sustainability and evolution of the ecosystem. Yet the fundamental ecological processes that govern the assemblage of these natural communities remain unclear. Here, we combined multivariate analyses, co-occurrence networks and fitted species abundance distributions of amplicon sequencing data to disentangle community assemblage patterns of polar soil microbiomes across two ice-free deserts (Windmill Islands and Vestfold Hills) situated along the coastline of eastern Antarctica. Our findings report that communities were predominantly structured by non-neutral processes, with niche partitioning being particularly strong for bacterial communities at the Windmill Islands. In contrast, both eukaryotic and archaeal communities exhibited multimodal distributions, indicating the potential emergence of neutrality. Between the three microbial domains, polar soil bacterial communities consistently demonstrated the greatest taxonomic diversity, estimated richness, network connectivity and linear response to contemporary environmental soil parameters. We propose that reduced niche overlap promotes greater phylogenetic diversity enabling more bacterial species to co-exist and essentially thrive under adversity. However, irrespective of overall relative abundance, consistent and robust associations between co-existing community members from all three domains of life highlights the key roles that diverse taxa play in ecosystem dynamics. SignificanceIn the face of a warming Antarctica, contemporary dynamics between polar soil microbial communities will inevitably change due to the climate-induced expansion of new ice-free areas. Increasing concern about disturbance and rapid biodiversity loss has intensified the need to better understand microbial community structure and function in high-latitude soils. We have taken an integrated approach to elucidate domain-level assemblage patterns across east Antarctic soil microbiomes. These assemblage patterns will be available to feed into policy management and conservation planning frameworks to potentially mitigate future biodiversity loss.

microbiology↗