349 research outputs found
Genome restructuring in mouse embryos during reprogramming and early development
AbstractAlthough a growing number of studies investigates functional genome organization in somatic cell nuclei, it is largely unknown how mammalian genome organization is established during embryogenesis. To address this question, we investigated chromocenter formation and the peculiar arrangements of chromosome domains in early mouse embryos. At the one-cell stage, we observed characteristic arrangements of chromosomes and chromocenter components. Subsequently, starting with the burst of zygotic genome transcription major rearrangements led to the establishment of somatic type chromocenters with a defined spatio-temporal organization. These processes appeared to be completed at the blastocyst stage with the onset of cell differentiation. During the same developmental period, a fraction of pericentric heterochromatin that was late replicating in the first cycle underwent switches in replication timing, spatial organization and epigenetic marks. Cloning experiments revealed that the genome organization typical for more advanced stages was quickly reverted into the one-cell stage-specific form after nuclear transfer, supporting the idea that reprogramming associated genome remodeling in normal and cloned embryos is determined by cytoplasmic factors. Together, the results suggest that distinct but characteristic forms of nuclear genome organization are required for genome reprogramming in early embryos and for proper regulation of differential gene expression patterns at later stages
Charge distribution across capped and uncapped infinite-layer neodymium nickelate thin films
Charge ordering (CO) phenomena have been widely debated in
strongly-correlated electron systems mainly regarding their role in
high-temperature superconductivity. Here, we elucidate the structural and
charge distribution in NdNiO thin films prepared with and without capping
layers, and characterized by the absence and presence of CO. Our
microstructural and spectroscopic analysis was done by scanning transmission
electron microscopy-electron energy loss spectroscopy (STEM-EELS) and hard
x-ray photoemission spectroscopy (HAXPES). Capped samples show Ni, with
an out-of-plane (o-o-p) lattice parameter of around 3.30 angstroms indicating
good stabilization of the infinite-layer structure. Bulk-sensitive HAXPES on
Ni-2p shows weak satellite feature indicating large charge-transfer energy. The
uncapped samples evidence an increase of the o-o-p parameter up to 3.65
angstroms on the thin-film top, and spectroscopies show signatures of higher
valence in this region (towards Ni). Here, 4D-STEM demonstrates (3,0,3)
oriented stripes which emerge from partially occupied apical oxygen. Those
stripes form quasi-2D coherent domains viewed as rods in the reciprocal space
with r.l.u. extension located at Q = () r.l.u. and Q = () r.l.u. The stripes associated with oxygen re-intercalation
concomitant with hole doping suggests a possible link to the previously
reported CO in infinite-layer nickelate thin films
Trichostatin A treatment of cloned mouse embryos improves constitutive heterochromatin remodeling as well as developmental potential to term
<p>Abstract</p> <p>Background</p> <p>Genome reprogramming in early mouse embryos is associated with nuclear reorganization and particular features such as the peculiar distribution of centromeric and pericentric heterochromatin during the first developmental stage. This zygote-specific heterochromatin organization could be observed both in maternal and paternal pronuclei after natural fertilization as well as in embryonic stem (ES) cell nuclei after nuclear transfer suggesting that this particular type of nuclear organization was essential for embryonic reprogramming and subsequent development.</p> <p>Results</p> <p>Here, we show that remodeling into a zygotic-like organization also occurs after somatic cell nuclear transfer (SCNT), supporting the hypothesis that reorganization of constitutive heterochromatin occurs regardless of the source and differentiation state of the starting material. However, abnormal nuclear remodeling was frequently observed after SCNT, in association with low developmental efficiency. When transient treatment with the histone deacetylase inhibitor trichostatin A (TSA) was tested, we observed improved nuclear remodeling in 1-cell SCNT embryos that correlated with improved rates of embryonic development at subsequent stages.</p> <p>Conclusion</p> <p>Together, the results suggest that proper organization of constitutive heterochromatin in early embryos is involved in the initial developmental steps and might have long term consequences, especially in cloning procedures.</p
Eating and weight related cognitions in people with Schizophrenia : A case control study
BACKGROUND: Patients with antipsychotic-induced weight gain (WG) regularly report on unsuccessful dietary trials, which suggests strong biological weight gain drive that is extremely hard to overcome with thoughts, such that behaviour doesn't change despite some intent to change. The purpose of the present study was to assess cognitions specifically related to restrained eating in severely overweight patients with schizophrenia treated with antipsychotic drugs. METHODS: Forty outpatients with schizophrenia and 40 controls without psychiatric disability were included. Both groups were composed of one subgroup severely overweight (defined as a BMI > 28), and a comparison sample (BMI<28). The revised version of the Mizes Anorectic cognitive questionnaire (MAC-R) was used in this cross-sectional case-control study. RESULTS: Gender was significantly related to eating disorders cognition, women scoring higher than men. Patients with schizophrenia in general scored higher on the MAC-R total scale and on the MAC-R subscale 2, the latter score representing rigid weight regulation and fear of weight gain. When comparing the two groups of subjects with BMI < 28, it appeared that patients with schizophrenia also scored higher on MAC-R total scale, the subscales 2 and 3, the latter subscale 3, indicating altered self control and self-esteem. CONCLUSION: As is the case in weight gain of subjects without schizophrenia, the present results suggest that the cognitive distortions, as assessed by the MAC-R, may play an important role in weight gain also in patients with schizophrenia, and in weight gain associated with antipsychotic pharmacotherapy. Particular attention to these processes may help to improve the management of antipsychotic drugs induced weight gain
Auto ADP-ribosylation of NarE, a Neisseria meningitidis ADP-ribosyltransferase, regulates its catalytic activities
NarE is an arginine-specific mono-ADPribosyltransferase
identified in Neisseria meningitidis
that requires the presence of iron in a structured
cluster for its enzymatic activities. In this study, we
show that NarE can perform auto-ADP-ribosylation.
This automodification occurred in a time- and NADconcentration-
dependent manner; was inhibited by novobiocin,
an ADP-ribosyltransferase inhibitor; and did
not occur when NarE was heat inactivated. No reduction
in incorporation was evidenced in the presence of
high concentrations of ATP, GTP, ADP-ribose, or nicotinamide,
which inhibits NAD-glycohydrolase, impeding
the formation of free ADP-ribose. Based on the
electrophoretic profile of NarE on auto-ADP-ribosylation
and on the results of mutagenesis and mass
spectrometry analysis, the auto-ADP-ribosylation appeared
to be restricted to the addition of a single
ADP-ribose. Chemical stability experiments showed
that the ADP-ribosyl linkage was sensitive to hydroxylamine,
which breaks ADP-ribose-arginine bonds. Sitedirected
mutagenesis suggested that the auto-ADP-ribosylation
site occurred preferentially on the R7 residue,
which is located in the region I of the ADP-ribosyltransferase
family. After auto-ADP-ribosylation, NarE
showed a reduction in ADP-ribosyltransferase activity,
while NAD-glycohydrolase activity was increased. Overall,
our findings provide evidence for a novel intramolecular
mechanism used by NarE to regulate its enzymatic
activities.—Picchianti, M., Del Vecchio, M., Di
Marcello, F., Biagini, M., Veggi, D., Norais N., Rappuoli,
R., Pizza, M., Balducci, E. Auto ADP-ribosylation
of NarE, a Neisseria meningitidis ADP-ribosyltransferase,
regulates its catalytic activities. FASEB J
Spin transport properties of spinel vanadate-based heterostructures
Spin-orbit coupling and breaking of inversion symmetry are necessary
ingredients to enable a pure spin current-based manipulation of the
magnetization via the spin-orbit torque effect. Currently, magnetic insulator
oxides with non-dissipative characteristics are being explored. When combined
with non-magnetic heavy metals, known for their large spin-orbit coupling, they
offer promising potential for energy-efficient spin-orbitronics applications.
The intrinsic electronic correlations characterizing those strongly correlated
oxides hold the promises to add extra control-knobs to the desired efficient
spin-wave propagation and abrupt magnetization switching phenomena. Spinel
vanadate FeV2O4 (FVO) exhibits several structural phase transitions which are
accompanied by an intricate interplay of magnetic, charge and orbital
orderings. When grown as a thin film onto SrTiO3, the compressive strain state
induces a perpendicular magnetic anisotropy, making FVO-based heterostructures
desirable for spin-orbitronics applications. In this study, we have optimised
the deposition of stoichiometric and epitaxial Pt/FVO heterostructures by
Pulsed Laser Deposition and examined their spin-related phenomena. From
angle-dependent magnetotransport measurements, we observed both Anisotropic
Magnetoresistance (AMR) and Spin Hall Magnetoresistance (SMR) effects. Our
findings show the SMR component as the primary contributor to the overall
magnetoresistance, whose high value of 0.12% is only comparable to properly
optimized oxide-based systems
Logic andknowledge of farmers in the northern part of Alto Paraná, Misiones and its contribution to a proposed Sustainable Rural Development
Se analizó, a través de sus prácticas, el modo de producción campesino, su lógica y conocimientos, en 5 chacras de la Provincia de Misiones. Los resultados preliminares confirman que este modo de producción se basa en un uso múltiple y más sustentable del territorio. Utiliza un manejo apropiado y complejo de la biodiversidad, con un gradiente de uso desde lo natural y silvestre hacia lo cultivado. Sus prácticas se basan en conocimientos, valores y una lógica diferente al modelo empresarial, importantes para el diseño de agroecosistemas más sustentables.It has been analyzed through its practices, the mode of production, its logic and knowledge of the peasants in 5 farms in the province of Misiones. Preliminary results confirm that this mode of production is based on a more sustainable multiple use planning, and appropriate management of biodiversity and complex, with a gradient from the natural and wild use into the cultivated. Their practices are based on knowledge, values and a different logic to the business model relevant to the design of more sustainable agroecosystems.Facultad de Ciencias Agrarias y Forestale
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