S100A4 is a Ca
2+
-binding protein that performs an important role in metastasis. It is also known for its antitumor functions. S100A4 is expressed by a specialized subset of CD
4+
CD
25+
lymphocytes ...and is present on those cell's membranes along with peptidoglycan recognition proteins (PGRPs). There, by interacting with major heat shock protein Hsp70, S100A4 plays an important cytotoxic role. The resulting stably formed complex of PGRPs, S100A4 and Hsp70 is required for the identification and binding between a lymphocyte and a target cell. Here, we investigated the S100A4 functions in CD
4+
CD
25+
PGRPs
+
S100A4
+
lymphocyte cytotoxicity against target cells. We demonstrated that those lymphocytes do not form a stable complex with the tumor target cells that themselves have S1004A on their surface. That observation can be explained by our finding that S100A4 precludes the formation of a stable complex between PGRPs, S100A4 (on the lymphocytes’ surface), and Hsp70 (on the target cells’ surface). The decrease in S100A4 level in CD
4+
CD
25+
PGRPs
+
S100A4
+
lymphocytes inhibits their cytotoxic activity, while the addition of S100A4 in the medium restores it. Thus, the resistance of target cells to CD
4+
CD
25+
PGRPs
+
S100A4
+
lymphocyte cytotoxicity depends on their S100A4 expression level and can be countered by S100A4 antibodies.
Strong electron interactions can drive metallic systems toward a variety of well-known symmetry-broken phases, but the instabilities of correlated metals with strong spin-orbit coupling have only ...recently begun to be explored. We uncovered a multipolar nematic phase of matter in the metallic pyrochlore Cd₂Re₂O₇ using spatially resolved second-harmonic optical anisotropy measurements. Like previously discovered electronic nematic phases, this multipolar phase spontaneously breaks rotational symmetry while preserving translational invariance. However, it has the distinguishing property of being odd under spatial inversion, which is allowed only in the presence of spin-orbit coupling. By examining the critical behavior of the multipolar nematic order parameter, we show that it drives the thermal phase transition near 200 kelvin in Cd₂Re₂O₇ and induces a parity-breaking lattice distortion as a secondary order.
Shugoshin is an evolutionarily conserved protein, which is involved in tension sensing on mitotic chromosomes, kinetochore biorientation, and protection of centromeric (
CEN
) cohesin for faithful ...chromosome segregation. Interaction of the C-terminus of Sgo1 with phosphorylated histone H2A regulates its association with
CEN
and pericentromeric (peri-
CEN
) chromatin, whereas mutations in histone H3 selectively compromise the association of Sgo1 with peri-
CEN
but not
CEN
chromatin. Given that histone H3 is absent from
CEN
and is replaced by a histone H3 variant CENP-A
Cse4
, we investigated if CENP-A
Cse4
interacts with Sgo1 and promotes its association with the
CEN
chromatin. In this study, we found that Sgo1 interacts with CENP-A
Cse4
in vivo
and
in vitro
. The N-terminus coiled-coil domain of Sgo1 without the C-terminus (
sgo1-NT
) is sufficient for its interaction with CENP-A
Cse4
, association with
CEN
but not the peri-
CEN
, and this
CEN
association is cell cycle dependent with maximum enrichment in mitosis. In agreement with the role of CENP-A
Cse4
in
CEN
maintenance of Sgo1, depletion of CENP-A
Cse4
results in the loss of Sgo1 and
sgo1-NT
from the
CEN
chromatin. The N-terminus of Sgo1 is required for genome stability as a mutant lacking the N-terminus (
sgo1-CT
) exhibits increased chromosome missegregation when compared to a
sgo1-NT
mutant. In summary, our results define a novel role for the N-terminus of Sgo1 in CENP-A
Cse4
mediated recruitment of Sgo1 to
CEN
chromatin for faithful chromosome segregation.
Coherent interaction with off-resonance light can be used to shift the energy levels of atoms, molecules, and solids. The dominant effect is the optical Stark shift, but there is an additional ...contribution from the so-called Bloch-Siegert shift that has eluded direct and exclusive observation in solids. We observed an exceptionally large Bloch-Siegert shift in monolayer tungsten disulfide (WS₂) under infrared optical driving. By controlling the light helicity, we could confine the Bloch-Siegert shift to occur only at one valley, and the optical Stark shift at the other valley, because the two effects obey opposite selection rules at different valleys. Such a large and valley-exclusive Bloch-Siegert shift allows for enhanced control over the valleytronic properties of two-dimensional materials.
The enzymatic β-C–H hydroxylation of the feedstock chemical isobutyric acid has enabled the asymmetric synthesis of a wide variety of polyketides. The analogous transition metal–catalyzed ...enantioselective β-C–H functionalization of isobutyric acid–derived substrates should provide a versatile method for constructing useful building blocks with enantioenriched α-chiral centers from this abundant C-4 skeleton. However, the desymmetrization of ubiquitous isopropyl moieties by organometallic catalysts has remained an unanswered challenge. Herein, we report the design of chiral mono-protected aminomethyl oxazoline ligands that enable desymmetrization of isopropyl groups via palladium insertion into the C(sp³)–H bonds of one of the prochiral methyl groups. We detail the enantioselective β-arylation, -alkenylation, and -alkynylation of isobutyric acid/2-aminoisobutyric acid derivatives, which may serve as a platform for the construction of α-chiral centers.
Dynamical error suppression techniques are commonly used to improve coherence in quantum systems. They reduce dephasing errors by applying control pulses designed to reverse erroneous coherent ...evolution driven by environmental noise. However, such methods cannot correct for irreversible processes such as energy relaxation. We investigate a complementary, stochastic approach to reducing errors: Instead of deterministically reversing the unwanted qubit evolution, we use control pulses to shape the noise environment dynamically. In the context of superconducting qubits, we implement a pumping sequence to reduce the number of unpaired electrons (quasiparticles) in close proximity to the device. A 70% reduction in the quasipartide density results in a threefold enhancement in qubit relaxation times and a comparable reduction in coherence variability.
We demonstrate that nanoparticle self-assembly can reach the same level of hierarchy, complexity, and accuracy as biomolecules. The precise assembly structures of gold nanopartides (246 gold core ...atoms with 80 p-methylbenzenethiolate surface ligands) at the atomic, molecular, and nanoscale levels were determined from x-ray diffraction studies. We identified the driving forces and rules that guide the multiscale assembly behavior. The protecting ligands self-organize into rotational and parallel patterns on the nanoparticle surface via C-H···π interaction, and the symmetry and density of surface patterns dictate directional packing of nanopartides into crystals with orientational, rotational, and translational orders. Through hierarchical interactions and symmetry matching, the simple building blocks evolve into complex structures, representing an emergent phenomenon in the nanoparticle system.
The sacral autonomie outflow is sympathetic Espinosa-Medina, I.; Saha, O.; Boismoreau, F. ...
Science (American Association for the Advancement of Science),
11/2016, Volume:
354, Issue:
6314
Journal Article
Peer reviewed
A kinship between cranial and pelvic visceral nerves of vertebrates has been accepted for a century. Accordingly, sacral preganglionic neurons are considered parasympathetic, as are their targets in ...the pelvic ganglia that prominently control rectal, bladder, and genital functions. Here, we uncover 15 phenotypic and ontogenetic features that distinguish pre- and postganglionic neurons of the cranial parasympathetic outflow from those of the thoracolumbar sympathetic outflow in mice. By every single one, the sacral outflow is indistinguishable from the thoracolumbar outflow. Thus, the parasympathetic nervous system receives input from cranial nerves exclusively and the sympathetic nervous system from spinal nerves, thoracic to sacral inclusively. This simplified, bipartite architecture offers a new framework to understand pelvic neurophysiology as well as development and evolution of the autonomie nervous system.
Field investigations and seismic data show that the 16 April 2016 moment magnitude (Mw) 7.1 Kumamoto earthquake produced a ~40-kilometer-long surface rupture zone along the ...northeast-southwest-striking Hinagu-Futagawa strike-slip fault zone and newly identified faults on the western side of Aso caldera, Kyushu Island, Japan. The coseismic surface ruptures cut Aso caldera, including two volcanic cones inside it, but terminate therein. The data show that northeastward propagation of coseismic rupturing terminated in Aso caldera because of the presence of magma beneath the Aso volcanic cluster. The seismogenic faults of the 2016 Kumamoto earthquake may require reassessment of the volcanic hazard in the vicinity of Aso volcano.
Efficient CO₂ transformation from a waste product to a carbon source for chemicals and fuels will require reaction conditions that effect its reduction. We developed a "super-dry" CH₄ reforming ...reaction for enhanced CO production from CH₄ and CO₂. We used Ni/MgAl₂O₄ as a CH₄-reforming catalyst, Fe₂O₃/MgAl₂O₄ as a solid oxygen carrier, and CaO/Al₂O₃ as a CO₂ sorbent. The isothermal coupling of these three different processes resulted in higher CO production as compared with that of conventional dry reforming, by avoiding back reactions with water. The reduction of iron oxide was intensified through CH₄ conversion to syngas over Ni and CO₂ extraction and storage as CaCO₃. CO₂ is then used for iron reoxidation and CO production, exploiting equilibrium shifts effected with inert gas sweeping (Le Chatelier's principle). Super-dry reforming uses up to three CO₂ molecules per CH₄ and offers a high CO space-time yield of 7.5 millimole CO per second per kilogram of iron at 1023 kelvin.
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