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Riquelme, C.

Publications and source records attributed to Riquelme, C..

4 recordsLinked to original sources
bioRxiv2025

Understanding the genetic diversity of bacteria isolated from across the Atacama Desert

Despite being one of the driest and harshest deserts on Earth, the Atacama Desert is home to a variety of bacterial life. Microorganisms that reside here may have developed adaptations to help them survive this unique environment. In this study, we used bioinformatic and genetic methods to assess the abundance of phyla that are present in this environment and what types of adaptations individual bacteria have obtained. To assess bacterial diversity, we used 16S rRNA sequencing on soil samples and determined the relative composition of different phyla and archaea at sixteen locations. A selection of eight cultivatable organisms which produce pigments were subjected to whole genome sequencing (WGS). Using these sequences, we screened for stress-tolerance capabilities including pigment production pathways, biofilm-related genes, antibiotic production, and genome stability. We found that all strains we sequenced are predicted to produce bioactive compounds. We also found that the pigments that these bacteria produce have antioxidant, iron and ion chelating, and/or antibiotic properties. This characterization allows us to assess adaptive strategies of bacteria which is important in the fields of agriculture, biotechnology and health.

microbiology↗
bioRxiv2024

Whole-Genome Sequencing of a Janthinobacterium sp. Isolated from the Patagonian Desert

Janthinobacterium is a genus of Gram-negative environmental bacteria that survive extreme conditions by forming biofilms and producing pigments. Janthinobacterium sp. LS2A, an extremophile isolated from soil in the Chilean Patagonia, contains seven known biosynthetic gene clusters, including the purple pigment violacein, which may aid in its survival in harsh environments.

genomics↗
bioRxiv2020

Insights into the diversity and survival strategies of soil bacterial isolates from the Atacama Desert

The Atacama Desert, the driest and oldest desert in the world, is a hostile environment for life. Despite the inhospitable conditions, bacterial sequences detected in this location suggest rich bacterial life. This study tested the idea that certain bacteria would thrive in this location and that some of them could be cultivated permitting further characterization. Environmental surface soil samples from 1-5 cm deep were collected from 18 diverse locations within the Atacama Desert. To assess the bacterial taxa, diversity, and abundance, Illumina 16S rRNA gene sequencing was performed directly on soil samples. Bacteria were also cultured from the samples. We have a collection of 74 unique bacterial isolates after cultivation and confirmation by 16S rRNA gene sequencing. Pigmentation, biofilm formation, antibiotic production against Escherichia coli MG1655 and Staphylococcus aureus HG003, and antibiotic resistance were assessed on these isolates. We found that approximately a third of the colonies produced pigments, 80% of isolates formed biofilms, many isolates had antibiotic activity against E. coli and/or S. aureus, and many were resistant to commercial antibiotics. The functional characterization of these isolates gives us insight into the adaptive bacterial strategies in harsh environments and enables us to learn about their possible use in agriculture, healthcare, or biotechnology. Originality-Significant StatementThis study provides the first microbial diversity analysis from Atacama Desert soil, presents the cultivation and isolation of 74 unique bacterial isolates, many of which may be novel genera and species, and explores pigment production, antibiotic production and resistance, and unique biofilm development as bacterial survival strategies for living within extreme environments.

microbiology↗