Amoebae Assemble Synthetic Spherical Particles To Form Reproducible Constructs

Area of Science:

• Microbiology
• Materials Science
• Environmental Science

Background:

• Difflugia are single-celled organisms (testate amoebae) that construct protective shells called tests or thecae using environmental particles.
• Understanding the materials and processes involved in test construction is crucial for taxonomy and biomimicry.

Purpose of the Study:

• To investigate the impact of synthetic microspheres on the growth rate and test construction of Difflugia globulosa.
• To analyze the morphology, composition, and construction techniques employed by Difflugia when using synthetic particles.

Main Methods:

• Culturing Difflugia globulosa with natural building materials and in the presence of synthetic silica (1, 3, 6 μm) and polystyrene (4 μm) microspheres.
• Utilizing optical and electron microscopy to examine the structure of the constructed thecae.
• Employing time-lapse photography to observe particle manipulation and test assembly processes.

Main Results:

• The presence of synthetic microspheres significantly accelerated Difflugia growth, with these foreign particles becoming the primary construction material.
• Difflugia constructed spherical, vase-shaped thecae with consistent morphology, size, and composition when using 6 μm silica particles.
• Observed sophisticated construction techniques, including particle herding, phagocytosis for particle capture, and internal application of biocement.

Conclusions:

• Synthetic particles dramatically enhance Difflugia growth and are readily incorporated into their tests, posing potential taxonomic challenges.
• Difflugia exhibit advanced biomicrofabrication capabilities, demonstrating controlled assembly of materials.
• The widespread use of synthetic particles by these organisms highlights a notable environmental impact of microplastic pollution.