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Valiei, A.

Publications and source records attributed to Valiei, A..

2 recordsLinked to original sources

MetaBiome: A Multiscale Model Integrating Agent-Based Modeling and Metabolic Networks Reveals Spatial Regulation in Mucosal Microbial Communities

Mucosal microbial communities (MMCs) are complex ecosystems near the mucosal layers of the gut, essential for maintaining health and modulating disease states. Despite advances in high-throughput omics technologies, current methodologies struggle to capture the dynamic metabolic interactions and spatiotemporal variations within MMCs. In this work, we present MetaBiome, a multiscale model integrating agent-based modeling (ABM), finite volume methods, and constraint-based models to explore the metabolic interactions within these communities. Integrating ABM allows for the detailed representation of individual microbial agents, each governed by rules that dictate cell growth, division, and interactions with their surroundings. Through a layered approach--encompassing environmental conditions, agent information, and metabolic pathways--we simulated different communities to showcase the potential of the model. Using our in-silico platform, we explored the dynamics and spatiotemporal patterns of MMCs in the proximal small intestine and the cecum, simulating the physiological conditions of the two gut regions. Our findings revealed how specific microbes adapt their metabolic processes based on substrate availability and local environmental conditions, shedding light on spatial metabolite regulation and informing targeted therapies for localized gut diseases. MetaBiome provides a detailed representation of microbial agents and their interactions, surpassing the limitations of traditional grid-based systems. This work marks a significant advancement in microbial ecology as it offers new insights into predicting and analyzing microbial communities. ImportanceOur study presents a novel multiscale model that combines agent-based modeling, finite volume methods, and genome-scale metabolic models to simulate the complex dynamics of mucosal microbial communities in the gut. This integrated approach allows us to capture spatial and temporal variations in microbial interactions and metabolism that are difficult to study experimentally. Key findings from our model include: O_LIPrediction of metabolic cross-feeding and spatial organization in multi-species communities C_LIO_LIInsights into how oxygen gradients and nutrient availability shape community composition in different gut regions C_LIO_LIIdentification of spatially-regulated metabolic pathways and enzymes in E. coli C_LI We believe this work represents a significant advance in computational modeling of microbial communities and provides new insights into the spatial regulation of gut microbiome metabolism. The multiscale modeling approach we have developed could be broadly applicable for studying other complex microbial ecosystems.

microbiology↗

Mechano-bactericidal nanopillars require external forces to effectively kill bacteria

Nanopillars are known to mechanically damage bacteria, suggesting a promising strategy for highly-effective anti-bacterial surfaces. However, the mechanisms underlying this phenomena remain unclear, which ultimately limits translational potential towards real-world applications. Using real-time and end-point analysis techniques, we demonstrate that in contrast to expectations, bacteria on multiple "mechano-bactericidal" surfaces remain viable, unless exposed to a moving air-liquid interface which caused considerable cell death. Reasoning that normal forces arising from surface tension may underlie mechano-bactericidal activity, we developed computational and experimental models to estimate, manipulate, and recreate the impact of these forces. Our experiments together demonstrate that nanopillar surfaces alone do not cause cell death, but require a critical level of external force to deform and rupture bacteria. These studies hence provide fundamental physical insight into the mechanisms by which nanopillar surfaces can serve as effective antibacterial strategies, and describe the use-conditions under which such nanotechnological approaches may provide practical value. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/012153v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@1cfded2org.highwire.dtl.DTLVardef@2dc47dorg.highwire.dtl.DTLVardef@bf002dorg.highwire.dtl.DTLVardef@1a49c2d_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

microbiology↗