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Microcapsules with an aqueous core can be conveniently prepared by water‐in‐oil‐in‐water double emulsion microfluidics. However, conventional shell materials are based on hydrophobic polymers or colloidal particles. Thus, these microcapsules feature a hydrophobic shell impermeable to water‐soluble compounds. Capsules with semipermeable hydrogel shells have been demonstrated but may exhibit poor mechanical properties. Here, amphiphilic polymer conetworks (APCNs) based on poly(2‐hydroxyethyl acrylate)‐linked by‐polydimethylsiloxane (PHEA‐l‐PDMS) are introduced as a new class of wall materials in double emulsion microcapsules. These APCNs are mechanically robust silicone hydrogels that are swellable and permeable to water and are soft and elastic when dry or swollen. Therefore, the microcapsules can be dried and rehydrated multiple times or shrunken in sodium chloride salt solutions without getting damaged. Moreover, the APCNs are permeable for hydrophilic organic compounds and impermeable for macromolecules. Thus, they can be loaded with macromolecules or nanoparticles during microfluidic formation and with organic molecules after capsule synthesis. The microcapsules serve as microreactors for catalytically active platinum nanoparticles that decompose hydrogen peroxide. Finally, the surface of the APCN microcapsules can be selectively functionalized with a cholesterol‐based linker. Concluding, APCN microcapsules could find applications for the controlled delivery of drugs, as microreactors for synthesis, or as scaffolds for synthetic cells.

 

Potassium ion (K+) channels have been observed in diverse viruses that infect eukaryotic marine and freshwater algae. However, experimental evidence for functional K+ channels among these alga-infecting viruses has thus far been restricted to members of the family Phycodnaviridae, which are large, double-stranded DNA viruses within the phylum Nucleocytoviricota. Recent sequencing projects revealed that alga-infecting members of Mimiviridae, another family within this phylum, may also contain genes encoding K+ channels. Here we examine the structural features and the functional properties of putative K+ channels from four cultivated members of Mimiviridae. While all four proteins contain variations of the conserved selectivity filter sequence of K+ channels, structural prediction algorithms suggest that only two of them have the required number and position of two transmembrane domains that are present in all K+ channels. After in vitro translation and reconstitution of the four proteins in planar lipid bilayers, we confirmed that one of them, a 79 amino acid protein from the virus Tetraselmis virus 1 (TetV-1), forms a functional ion channel with a distinct selectivity for K+ over Na+ and a sensitivity to Ba2+. Thus, virus-encoded K+ channels are not limited to Phycodnaviridae but also occur in the members of Mimiviridae. The large sequence diversity among the viral K+ channels implies multiple events of lateral gene transfer. 

Chloroviruses are large, plaque-forming, dsDNA viruses that infect chlorella-like green algae that live in a symbiotic relationship with protists. Chloroviruses have genomes from 290 to 370 kb, and they encode as many as 400 proteins. One interesting feature of chloroviruses is that they encode a potassium ion (K+) channel protein named Kcv. The Kcv protein encoded by SAG chlorovirus ATCV-1 is one of the smallest known functional K+ channel proteins consisting of 82 amino acids. The KcvATCV-1 protein has similarities to the family of two transmembrane domain K+ channel proteins; it consists of two transmembrane α-helixes with a pore region in the middle, making it an ideal model for studying K+ channels. To assess their genetic diversity, kcv genes were sequenced from 103 geographically distinct SAG chlorovirus isolates. Of the 103 kcv genes, there were 42 unique DNA sequences that translated into 26 new Kcv channels. The new predicted Kcv proteins differed from KcvATCV-1 by 1 to 55 amino acids. The most conserved region of the Kcv protein was the filter, the turret and the pore helix were fairly well conserved, and the outer and the inner transmembrane domains of the protein were the most variable. Two of the new predicted channels were shown to be functional K+ channels.