21 research outputs found
Climate drives the geography of marine consumption by changing predator communities
Este artículo contiene 7 páginas, 3 figuras, 1 tabla.The global distribution of primary production and consumption by
humans (fisheries) is well-documented, but we have no map linking
the central ecological process of consumption within food
webs to temperature and other ecological drivers. Using standardized
assays that span 105° of latitude on four continents, we show
that rates of bait consumption by generalist predators in shallow
marine ecosystems are tightly linked to both temperature and the
composition of consumer assemblages. Unexpectedly, rates of
consumption peaked at midlatitudes (25 to 35°) in both Northern
and Southern Hemispheres across both seagrass and unvegetated
sediment habitats. This pattern contrasts with terrestrial systems,
where biotic interactions reportedly weaken away from the equator,
but it parallels an emerging pattern of a subtropical peak in
marine biodiversity. The higher consumption at midlatitudes was
closely related to the type of consumers present, which explained
rates of consumption better than consumer density, biomass, species
diversity, or habitat. Indeed, the apparent effect of temperature
on consumption was mostly driven by temperature-associated turnover
in consumer community composition. Our findings reinforce
the key influence of climate warming on altered species composition
and highlight its implications for the functioning of Earth’s
ecosystems.We acknowledge funding from the Smithsonian
Institution and the Tula Foundation.Peer reviewe
Iron-Catalyzed Formation of 2‑Aminopyridines from Diynes and Cyanamides
Diynes and cyanamides undergo an iron-catalyzed [2 +
2 + 2] cycloaddition to form highly substituted 2-aminopyridines in
an atom-efficient manner that is both high yielding and regioselective.
This system was also used to cyclize two terminal alkynes and a cyanamide
to afford a 2,4,6-trisubstituted pyridine product regioselectively
Iron-Catalyzed Formation of 2‑Aminopyridines from Diynes and Cyanamides
Diynes and cyanamides undergo an iron-catalyzed [2 +
2 + 2] cycloaddition to form highly substituted 2-aminopyridines in
an atom-efficient manner that is both high yielding and regioselective.
This system was also used to cyclize two terminal alkynes and a cyanamide
to afford a 2,4,6-trisubstituted pyridine product regioselectively
Iron-Catalyzed Formation of 2‑Aminopyridines from Diynes and Cyanamides
Diynes and cyanamides undergo an iron-catalyzed [2 +
2 + 2] cycloaddition to form highly substituted 2-aminopyridines in
an atom-efficient manner that is both high yielding and regioselective.
This system was also used to cyclize two terminal alkynes and a cyanamide
to afford a 2,4,6-trisubstituted pyridine product regioselectively
Single Diastereomer of a Macrolactam Core Binds Specifically to Myeloid Cell Leukemia 1 (MCL1)
A direct binding screen of 100 000
sp<sup>3</sup>-rich molecules
identified a single diastereomer of a macrolactam core that binds
specifically to myeloid cell leukemia 1 (MCL1). A comprehensive toolbox
of biophysical methods was applied to validate the original hit and
subsequent analogues and also established a binding mode competitive
with NOXA BH3 peptide. X-ray crystallography of ligand bound to MCL1
reveals a remarkable ligand/protein shape complementarity that diverges
from previously disclosed MCL1 inhibitor costructures
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Climate drives the geography of marine consumption by changing predator communities
The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth's ecosystems
Perivascular Secretome Influences Hematopoietic Stem Cell Maintenance in a Gelatin Hydrogel
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Dominant negative variants in IKZF2 cause ICHAD syndrome, a new disorder characterised by immunodysregulation, craniofacial anomalies, hearing impairment, athelia and developmental delay
BackgroundHelios (encoded by IKZF2), a member of the Ikaros family of transcription factors, is a zinc finger protein involved in embryogenesis and immune function. Although predominantly recognised for its role in the development and function of T lymphocytes, particularly the CD4+ regulatory T cells (Tregs), the expression and function of Helios extends beyond the immune system. During embryogenesis, Helios is expressed in a wide range of tissues, making genetic variants that disrupt the function of Helios strong candidates for causing widespread immune-related and developmental abnormalities in humans.MethodsWe performed detailed phenotypic, genomic and functional investigations on two unrelated individuals with a phenotype of immune dysregulation combined with syndromic features including craniofacial differences, sensorineural hearing loss and congenital abnormalities.ResultsGenome sequencing revealed de novo heterozygous variants that alter the critical DNA-binding zinc fingers (ZFs) of Helios. Proband 1 had a tandem duplication of ZFs 2 and 3 in the DNA-binding domain of Helios (p.Gly136_Ser191dup) and Proband 2 had a missense variant impacting one of the key residues for specific base recognition and DNA interaction in ZF2 of Helios (p.Gly153Arg). Functional studies confirmed that both these variant proteins are expressed and that they interfere with the ability of the wild-type Helios protein to perform its canonical function—repressing IL2 transcription activity—in a dominant negative manner.ConclusionThis study is the first to describe dominant negative IKZF2 variants. These variants cause a novel genetic syndrome characterised by immunodysregulation, craniofacial anomalies, hearing impairment, athelia and developmental delay