Synthesis of empty bacterial microcompartments, directed organelle protein incorporation, and evidence of filament-associated organelle movement

Compartmentalization is an important process, since it allows the segregation of metabolic activities and, in the era of synthetic biology, represents an important tool by which defined microenvironments can be created for specific metabolic functions. Indeed, some bacteria make specialized proteinaceous metabolic compartments called bacterial microcompartments (BMCs) or metabolosomes. Here we demonstrate that the shell of the metabolosome (representing an empty BMC) can be produced within E. coil cells by the coordinated expression of genes encoding structural proteins. A plethora of diverse structures can be generated by changing the expression profile of these genes, including the formation of large axial filaments that interfere with septation. Fusing GFP to PduC, PduD, or PduV, none of which are shell proteins, allows regiospecific targeting of the reporter group to the empty BMC. Live cell imaging provides unexpected evidence of filament-associated BMC movement within the cell in the presence of Pdu

Roadmap on semiconductor-cell biointerfaces.

This roadmap outlines the role semiconductor-based materials play in understanding the complex biophysical dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mechanical devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biological components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biological world

Bottom-up assembly of functional intracellular synthetic organelles by droplet-based microfluidics

Bottom-up synthetic biology has directed most efforts toward the construction of artificial compartmentalized systems that recreate living cell functions in their mechanical, morphological, or metabolic characteristics. However, bottom-up synthetic biology also offers great potential to study subcellular structures like organelles. Because of their intricate and complex structure, these key elements of eukaryotic life forms remain poorly understood. Here, the controlled assembly of lipid enclosed, organelle-like architectures is explored by droplet-based microfluidics. Three types of giant unilamellar vesicles (GUVs)-based synthetic organelles (SOs) functioning within natural living cells are procedured: (A) synthetic peroxisomes supporting cellular stress-management, mimicking an organelle innate to the host cell by using analogous enzymatic modules; (B) synthetic endoplasmic reticulum (ER) as intracellular light-responsive calcium stores involved in intercellular calcium signalling, mimicking an organelle innate to the host cell but utilizing a fundamentally different mechanism; and (C) synthetic magnetosomes providing eukaryotic cells with a magnetotactic sense, mimicking an organelle that is not natural to the host cell but transplanting its functionality from other branches of the phylogenetic tree. Microfluidic assembly of functional SOs paves the way for high-throughput generation of versatile intracellular structures implantable into living cells. This in-droplet SO design may support or expand cellular functionalities in translational nanomedicine

Wolffia globosa as a biocatalyst in plant-based biofuel cells

The rootless duckweed Wolffia globosa, not explored toward electrogenicity till now, is investigated as a putative biocatalyst in plant-based biofuel cells (P-BFC) for the electrical current generation and its basic metabolic changes during the polarization are depicted. After a short adaptation period, the open-circuit voltage of P-BFC, utilizing W. globosa as an anodic biocatalyst, reaches values of 630 mV. At a connected external resistor of 1 kΩ in the electric circuit, stable current densities of 170±10 mA m-2 are achieved. The electrical outputs depend on the anodic potential, reaching negative values of ca. -200 mV (vs. SHE). W. globosa produces an electrochemically active compound, acting as an electron shuttle. The polarization intensifies the W. globosa metabolism, expressed in a double increased glucose and starch content along with 1.82 times higher specific amylase activity of 70.0±2.8 U g-1 wet biomass in the organelle-enriched fractions of the explored as biocatalysts plants compared to the control. The results reveal that Wolffia globosa can be utilized as a biocatalyst in P-BFC for simultaneous electricity generation and increased carbohydrate and protein content