Anton Kan

Last Name

Kan

First Name

Anton

ORCID

0000-0001-9058-0464

Organisational unit

03831 - Studart, André R. / Studart, André R.

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Publications 1 - 8 of 8

Metabolic interactions control the transfer and spread of plasmid-encoded antibiotic resistance during surface-associated microbial growth
Ma, Yinyin; Kan, Anton; Johnson, David R. (2024)
Cell Reports
Surface-associated microbial systems are hotspots for the spread of plasmid-encoded antibiotic resistance, but how surface association affects plasmid transfer and proliferation remains unclear. Surface association enables prolonged spatial proximities between different populations, which promotes plasmid transfer between them. However, surface association also fosters strong metabolic interactions between different populations, which can direct their spatial self-organization with consequences for plasmid transfer and proliferation. Here, we hypothesize that metabolic interactions direct the spatial self-organization of different populations and, in turn, regulate the spread of plasmid-encoded antibiotic resistance. We show that resource competition causes populations to spatially segregate, which represses plasmid transfer. In contrast, resource cross-feeding causes populations to spatially intermix, which promotes plasmid transfer. We further show that the spatial positionings that emerge from metabolic interactions determine the proliferation of plasmid recipients. Our results demonstrate that metabolic interactions are important regulators of both the transfer and proliferation of plasmid-encoded antibiotic resistance.
Complex Living Materials Made by Light-Based Printing of Genetically Programmed Bacteria
Binelli, Marco R.; Kan, Anton; Rozas, Luis E. A.; et al. (2023)
Advanced Materials
Living materials with embedded microorganisms can genetically encode attractive sensing, self-repairing, and responsive functionalities for applications in medicine, robotics, and infrastructure. While the synthetic toolbox for genetically engineering bacteria continues to expand, technologies to shape bacteria-laden living materials into complex 3D geometries are still rather limited. Here, it is shown that bacteria-laden hydrogels can be shaped into living materials with unusual architectures and functionalities using readily available light-based printing techniques. Bioluminescent and melanin-producing bacteria are used to create complex materials with autonomous chemical-sensing capabilities by harnessing the metabolic activity of wild-type and engineered microorganisms. The shaping freedom offered by printing technologies and the rich biochemical diversity available in bacteria provides ample design space for the creation and exploration of complex living materials with programmable functionalities for a broad range of applications.
Directed evolution of material-producing microorganisms
Laurent, Julie Marine; Jain, Ankit; Kan, Anton; et al. (2024)
Proceedings of the National Academy of Sciences of the United States of America
Nature is home to a variety of microorganisms that create materials under environmentally friendly conditions. While this offers an attractive approach for sustainable manufacturing, the production of materials by native microorganisms is usually slow and synthetic biology tools to engineer faster microorganisms are only available when prior knowledge of genotype–phenotype links is available. Here, we utilize a high-throughput directed evolution platform to enhance the fitness of whole microorganisms under selection pressure and identify genetic pathways to enhance the material production capabilities of native species. Using Komagataeibacter sucrofermentans as a model cellulose-producing microorganism, we show that our droplet-based microfluidic platform enables the directed evolution of these bacteria toward a small number of cellulose overproducers from an initial pool of 40,000 random mutants. Sequencing of the evolved strains reveals an unexpected link between the cellulose-forming ability of the bacteria and a gene encoding a protease complex responsible for protein turnover in the cell. The ability to enhance the fitness of microorganisms toward a specific phenotype and to unravel genotype–phenotype links makes this high-throughput directed evolution platform a promising tool for the development of new strains for the sustainable manufacturing of materials.
Living Porous Ceramics for Bacteria-Regulated Gas Sensing and Carbon Capture
Dutto, Alessandro; Kan, Anton; Saraw, Zoubeir; et al. (2025)
Advanced Materials
Microorganisms hosted in abiotic structures have led to engineered living materials that can grow, sense, and adapt in ways that mimic biological systems. Although porous structures should favor colonization by microorganisms, they have not yet been exploited as abiotic scaffolds for the development of living materials. Here, porous ceramics are reported that are colonized by bacteria to form an engineered living material with self-regulated and genetically programmable carbon capture and gas-sensing functionalities. The carbon capture capability is achieved using wild-type photosynthetic cyanobacteria, whereas the gas-sensing function is generated utilizing genetically engineered E. coli. Hierarchical porous clay is used as a ceramic scaffold and evaluated in terms of bacterial growth, water uptake, and mechanical properties. Using state-of-the-art chemical analysis techniques, the ability of the living porous ceramics are demonstrated to capture CO2 directly from the air and to metabolically turn minute amounts of toxic gas into a benign scent detectable by humans.
Periplasmic stress contributes to a trade-off between protein secretion and cell growth in Escherichia coli Nissle 1917
Emani, Sivaram Subaya; Kan, Anton; Storms, Timothy; et al. (2023)
Synthetic Biology
Maximizing protein secretion is an important target in the design of engineered living systems. In this paper, we characterize a trade-off between cell growth and per-cell protein secretion in the curli biofilm secretion system of Escherichia coli Nissle 1917. Initial characterization using 24-h continuous growth and protein production monitoring confirms decreased growth rates at high induction, leading to a local maximum in total protein production at intermediate induction. Propidium iodide (PI) staining at the endpoint indicates that cellular death is a dominant cause of growth reduction. Assaying variants with combinatorial constructs of inner and outer membrane secretion tags, we find that diminished growth at high production is specific to secretory variants associated with periplasmic stress mediated by outer membrane secretion and periplasmic accumulation of protein containing the outer membrane transport tag. RNA sequencing experiments indicate upregulation of known periplasmic stress response genes in the highly secreting variant, further implicating periplasmic stress in the growth–secretion trade-off. Overall, these results motivate additional strategies for optimizing total protein production and longevity of secretory engineered living systems.
Phage predation accelerates the spread of plasmid-encoded antibiotic resistance
Ruan, Chujin; Ramoneda, Josep; Kan, Anton; et al. (2024)
Nature Communications
Phage predation is generally assumed to reduce microbial proliferation while not contributing to the spread of antibiotic resistance. However, this assumption does not consider the effect of phage predation on the spatial organization of different microbial populations. Here, we show that phage predation can increase the spread of plasmid-encoded antibiotic resistance during surface-associated microbial growth by reshaping spatial organization. Using two strains of the bacterium Escherichia coli, we demonstrate that phage predation slows the spatial segregation of the strains during growth. This increases the number of cell-cell contacts and the extent of conjugation-mediated plasmid transfer between them. The underlying mechanism is that phage predation shifts the location of fastest growth from the biomass periphery to the interior where cells are densely packed and aligned closer to parallel with each other. This creates straighter interfaces between the strains that are less likely to merge together during growth, consequently slowing the spatial segregation of the strains and enhancing plasmid transfer between them. Our results have implications for the design and application of phage therapy and reveal a mechanism for how microbial functions that are deleterious to human and environmental health can proliferate in the absence of positive selection.
Complex Materials: The Tough Life of Bone
Magrini, Tommaso; Libanori, Rafael; Kan, Anton; et al. (2021)
Revista Brasileira de Ensino de Física
Bone was a crucial biological material for the evolution of large terrestrial organisms and is today essential for most of our daily activities and well-being. From an engineering perspective, this living material features highly desirable properties for modern load-bearing structures. It is made of abundant and environmental-friendly building blocks, which are combined into a tough and durable structure that can continuously modify itself to adapt to changes in the mechanical load imposed by the surroundings. In this review article, we compile and discuss scientific findings that allow us to understand bone as a complex system with properties that emerge from cell-mediated interactions of molecules and particles at multiple length scales. Analogous to other complex systems, such interactions lead to self-organization, hierarchical structures and adaptive behavior without the need of a central controlling unit. A rich range of physical, chemical and biological phenomena provide a framework for information to be generated and processed in this complex system. Understanding the interplay between such underlying phenomena and their emerging properties should help the diagnosis and treatment of bone-related medical conditions and might provide guidelines for the future development of more sustainable materials and engineering structures.
Genetic Impacts on the Structure and Mechanics of Cellulose Made by Bacteria
Laurent, Julie M.; Steinacher, Mathias; Kan, Anton; et al. (2025)
Advanced Science
The synthesis of cellulose pellicles by bacteria offers an enticing strategy for the biofabrication of sustainable materials and biomedical devices. To leverage this potential, bacterial strains that overproduce cellulose are identified through directed evolution technology. While cellulose overproduction is linked with a specific genetic mutation, the effect of such mutation on the intracellular protein landscape and on the structure and mechanical properties of the cellulose pellicles is not yet understood. Here, the proteome of bacteria evolved to overproduce cellulose is studied and its effect on the structure and mechanics of the resulting cellulose pellicles is investigated. Proteomic analysis reveals that the protein landscape of the evolved bacteria shows pronounced differences from that of native microorganisms. Thanks to concerted changes in the proteome, the evolved bacteria can generate cellulose pellicles with exquisite structure and improved mechanical properties for applications in textiles, packaging, and medical implants.

Publications 1 - 8 of 8

Anton Kan

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