The underrepresentation of non-Europeans in human genetic studies so far has limited the diversity of individuals in genomic datasets and led to reduced medical relevance for a large proportion of the world's population. Population-specific reference genome datasets as well as genome-wide association studies in diverse populations are needed to address this issue. Here we describe the pilot phase of the GenomeAsia 100K Project. This includes a whole-genome sequencing reference dataset from 1,739 individuals of 219 population groups and 64 countries across Asia. We catalogue genetic variation, population structure, disease associations and founder effects. We also explore the use of this dataset in imputation, to facilitate genetic studies in populations across Asia and worldwide.
Covalent
organic frameworks (COFs) are promising candidates as
heterogeneous photocatalysts because of their porosity and tunable
light absorption. The photostability and charge separation of COFs
are highly important to improve the efficiency of photocatalytic transformation.
In this work, a fully conjugated donor–acceptor COF is constructed
with a benzothiadiazole unit, which exhibits high stability and enhanced
charge separation. The prepared COF can efficaciously produce superoxide
radical anions under air and visible light, which mediate the photocatalytic
oxidative amine coupling and cyclization of thioamide to 1,2,4-thiadiazole
in moderate to high yield and high recyclability (18 examples). This
study demonstrates the great capacity of fully conjugated COFs with
a D–A structure for light-driven organic synthesis.
The nucleoside analog remdesivir (RDV) is a Food and Drug Administration–approved antiviral for treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Thus, it is critical to understand factors that promote or prevent RDV resistance. We passaged SARS-CoV-2 in the presence of increasing concentrations of GS-441524, the parent nucleoside of RDV. After 13 passages, we isolated three viral lineages with phenotypic resistance as defined by increases in half-maximal effective concentration from 2.7- to 10.4-fold. Sequence analysis identified nonsynonymous mutations in nonstructural protein 12 RNA-dependent RNA polymerase (
nsp12
-RdRp): V166A, N198S, S759A, V792I, and C799F/R. Two lineages encoded the S759A substitution at the RdRp Ser
759
-Asp-Asp active motif. In one lineage, the V792I substitution emerged first and then combined with S759A. Introduction of S759A and V792I substitutions at homologous
nsp12
positions in murine hepatitis virus demonstrated transferability across betacoronaviruses; introduction of these substitutions resulted in up to 38-fold RDV resistance and a replication defect. Biochemical analysis of SARS-CoV-2 RdRp encoding S759A demonstrated a roughly 10-fold decreased preference for RDV-triphosphate (RDV-TP) as a substrate, whereas
nsp12
-V792I diminished the uridine triphosphate concentration needed to overcome template-dependent inhibition associated with RDV. The in vitro–selected substitutions identified in this study were rare or not detected in the greater than 6 million publicly available
nsp12
-RdRp consensus sequences in the absence of RDV selection. The results define genetic and biochemical pathways to RDV resistance and emphasize the need for additional studies to define the potential for emergence of these or other RDV resistance mutations in clinical settings.
Photocatalytic nitrogen fixation
reaction can harvest the solar
energy to convert the abundant but inert N2 into NH3. Here, utilizing metal–organic framework (MOF) membranes
as the ideal assembly of nanoreactors to disperse and confine gold
nanoparticles (AuNPs), we realize the direct plasmonic photocatalytic
nitrogen fixation under ambient conditions. Upon visible irradiation,
the hot electrons generated on the AuNPs can be directly injected
into the N2 molecules adsorbed on Au surfaces. Such N2 molecules can be additionally activated by the strong but
evanescently localized surface plasmon resonance field, resulting
in a supralinear intensity dependence of the ammonia evolution rate
with much higher apparent quantum efficiency and lower apparent activation
energy under stronger irradiation. Moreover, the gas-permeable Au@MOF
membranes, consisting of numerous interconnected nanoreactors, can
ensure the dispersity and stability of AuNPs, further facilitate the
mass transfer of N2 molecules and (hydrated) protons, and
boost the plasmonic photocatalytic reactions at the designed gas–membrane–solution
interface. As a result, an ammonia evolution rate of 18.9 mmol gAu
–1 h–1 was achieved under
visible light (>400 nm, 100 mW cm–2) with an
apparent
quantum efficiency of 1.54% at 520 nm.
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