Biology subjects

Tong, C.

Publications and source records attributed to Tong, C..

39 records · Page 3Linked to original sources

bioRxiv2019

Comparative genomics identifies putative signatures of sociality in spiders

Comparative genomics has begun to elucidate the genomic basis of social life in insects but insight into the genomic basis of spider sociality has lagged behind. To begin to characterize genomic signatures associated with the evolution of social life in spiders, we performed one of the first spider comparative genomics studies including five solitary species and two social species, representing two independent origins of sociality in the genus Stegodyphus. We found that the two social spider species had a large expansion of gene families associated with transport and metabolic processes and an elevated genome-wide rate of molecular evolution compared with the five solitary spider species. Genes that were rapidly evolving in the two social species relative to the five solitary species were enriched for transport, behavior, and immune functions, while genes that were rapidly evolving in the solitary species were enriched for energy metabolism processes. Most rapidly evolving genes in the social species S. dumicola were broadly expressed across four tissues and enriched for transport functions, but 12 rapidly evolving genes showed brain-specific expression and were enriched for social behavioral processes. Altogether, our study identifies putative genomic signatures and potential candidate genes associated with spider sociality. These results indicate that future spider comparative genomic studies, including broader sampling and additional independent origins of sociality, can further clarify the genomic causes and consequences of social life.

evolutionary biology↗

bioRxiv2019

Cartography of opportunistic pathogens and antibiotic resistance genes in a tertiary hospital environment

There is growing attention surrounding hospital acquired infections (HAIs) due to high associated healthcare costs, compounded by the scourge of widespread multi-antibiotic resistance. Although hospital environment disinfection is well acknowledged to be key for infection control, an understanding of colonization patterns and resistome profiles of environment-dwelling microbes is currently lacking. We report the first extensive genomic characterization of microbiomes (428), common HAI-associated microbes (891) and transmissible drug resistance cassettes (1435) in a tertiary hospital environment based on a 3-timepoint sampling (1 week and >1 year apart) of 179 sites from 45 beds. Deep shotgun metagenomic sequencing unveiled two distinct ecological niches of microbes and antibiotic resistance genes characterized by biofilm-forming and human microbiome influenced environments that display corresponding patterns of divergence over space and time. To study common nosocomial pathogens that were typically present at low abundances, a combination of culture enrichment and long-read nanopore sequencing was used to obtain thousands of high contiguity genomes (2347), phage sequences (1693) and closed plasmids (5910), a significant fraction of which (>60%) are not represented in current sequence databases. These high-quality assemblies and metadata enabled a rich characterization of resistance gene combinations, phage diversity, plasmid architectures, and the dynamic nature of hospital environment resistomes and their reservoirs. Phylogenetic analysis identified multidrug resistant strains as being more widely distributed and stably colonizing across hospital sites. Further genomic comparisons with clinical isolates across multiple species supports the hypothesis that multidrug resistant strains can persist in the hospital environment for extended periods (>8 years) to opportunistically infect patients. These findings highlight the importance of characterizing antibiotic resistance reservoirs in the hospital environment and establishes the feasibility of systematic genomic surveys to help target resources more efficiently for preventing HAIs.

microbiology↗

bioRxiv2017

Collective membrane dynamics emerging from curvature-dependent spatial coupling

Membrane curvature has been recognized as an active participant of fundamental biological processes including vesicular transport and organelle biogenesis, but its effects on membrane remodeling are typically local. Here we show membrane curvature plays a critical role in propagating cortical waves and modulating mesoscale dynamics in living cells. We employ a membrane shape-dependent mechanochemical feedback model to account for the observed oscillatory travelling waves of Cdc42, F-BAR proteins and actin. We demonstrate that oscillatory membrane shape changes accompany and are required for such spatiotemporal patterns. In addition, modulating the curvature preference of the F-BAR proteins or membrane tension perturbs wave propagation. Our findings identify a distinct role of membrane curvature in mediating collective dynamics of cortical proteins and provide a molecular framework for integrating membrane mechanics and biochemical signaling in the context of subcellular pattern formation.

biophysics↗