No abstract

Viral egress and transmission have long been described to take place through single free virus particles. However, viruses can also shed into the environment and transmit as populations clustered inside extracellular vesicles (EVs), a process we had first called vesicle-mediated en bloc transmission. These membrane-cloaked virus clusters can originate from a variety of cellular organelles including autophagosomes, plasma membrane, and multivesicular bodies. Their viral cargo can be multiples of nonenveloped or enveloped virus particles or even naked infectious genomes, but egress is always nonlytic, with the cell remaining intact. Here we put forth the thesis that EV-cloaked viral clusters are a distinct form of infectious unit as compared to free single viruses (nonenveloped or enveloped) or even free virus aggregates. We discuss how efficient and prevalent these infectious EVs are in the context of virus-associated diseases and highlight the importance of their proper detection and disinfection for public health. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Multivariate metal−organic frameworks (MTV-MOFs) have drawn much attention in recent years for their promising applications in many fields of chemistry and materials. Constructing functional MOFs from multiple components for electrochemical water is crucial to high performance renewable energy storage and conversion devices. In this work, a series of bitmetallic-, trimetallic-, and tetrametallic-MOF-74/NFs were grown in situ on nickel foam (NF) by a facile solvothermal route. Specifically, the optimized FeCoMnNi-MOF-74/NF with a multilevel and hollow nanostructure was successfully fabricated and used as highly efficient bifunctional electrocatalysts for water splitting. It exhibited an ultralow overpotential of 250 and 108 mV to achieve the current density of 50 and 10 mA cm −2 , along with the relatively small Tafel slope of 41.28 and 72.89 mV dec −1 for OER and HER in 1 M KOH, respectively. It is superior to other multimetallic-MOF-74 composites at the same condition and also surpasses the benchmark of commercial noble-metal catalysts as well. As a result, a low cell voltage of ca. 1.62 V was obtained at a current density of 10 mA cm −2 , when tetrametallic FeCoMnNi-MOF-74/NF is employed as both anode and cathode electrodes for the real water splitting. The present work potentially provides a new insight into prospecting and designing multivariate MOFs as a promising material for efficient electrocatalysis in the practical application.