Applications of Ionic Liquids in Whole-Cell and Isolated Enzyme Biocatalysis.

Ionic liquids have unique chemical properties that have fascinated scientists in many fields. The effects of adding ionic liquids to biocatalysts are many and varied. The uses of ionic liquids in biocatalysis include improved separations and phase behaviour, reduction in toxicity, and stabilization of protein structures. As the ionic liquid state of the art has progressed, concepts of what can be achieved in biocatalysis using ionic liquids have evolved and more beneficial effects have been discovered. In this review ionic liquids for whole-cell and isolated enzyme biocatalysis will be discussed with an emphasis on the latest developments, and a look to the future.

Why Cells and Viruses Cannot Survive without an ESCRT.

Intracellular organelles enwrapped in membranes along with a complex network of vesicles trafficking in, out and inside the cellular environment are one of the main features of eukaryotic cells. Given their central role in cell life, compartmentalization and mechanisms allowing their maintenance despite continuous crosstalk among different organelles have been deeply investigated over the past years. Here, we review the multiple functions exerted by the endosomal sorting complex required for transport (ESCRT) machinery in driving membrane remodeling and fission, as well as in repairing physiological and pathological membrane damages. In this way, ESCRT machinery enables different fundamental cellular processes, such as cell cytokinesis, biogenesis of organelles and vesicles, maintenance of nuclear-cytoplasmic compartmentalization, endolysosomal activity. Furthermore, we discuss some examples of how viruses, as obligate intracellular parasites, have evolved to hijack the ESCRT machinery or part of it to execute/optimize their replication cycle/infection. A special emphasis is given to the herpes simplex virus type 1 (HSV-1) interaction with the ESCRT proteins, considering the peculiarities of this interplay and the need for HSV-1 to cross both the nuclear-cytoplasmic and the cytoplasmic-extracellular environment compartmentalization to egress from infected cells.

Viruses and viral epidemics in the metabolic theory of evolution.

Viruses, including the SARS-CoV-2 virus responsible for the current COVID-19 epidemic, are a key to the understanding of life and evolution. Cells may have arisen from aqueous sequestration inside a lipid envelope studded with chromophores capable of capturing solar photons. Nitrogen incorporation in the primordial cell chemistry allowed synthesis of amino acids and nucleic acids, a prelude to RNA and subsequently DNA. Metagenomics provides access to nucleoprotein sediments synthesised by a googol of metabolically differentiated cells that have marked the evolution of life. Replication of a virus, a nucleoprotein particle, occurs passively in competent cells. Viruses are only identified in the context of the epidemic that they induce as a result of transmission from one host to another. By breaking down the viral particle, the host cell appears to resurrect the metabolic function of the nucleic acid, which synthesises its components without any form of control. Viral products undergo self-assembly and are exported by either exocytosis or cytolysis. In the absence of cells, viruses appear to be inert. However, intracellular contamination of a virus does not always result in replication: the viral genome can disappear, remain latent, wake up, remain embedded in the cellular genome, become an oncogene or induce auto-immunity. The presence of endogenous retroviruses in eukaryotic cells raises the question of their possible role in evolution.