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Upregulation of nuclear factor κB (NFκB) signaling is a hallmark of aging and a major cause of age‐related chronic inflammation. However, its effect on cellular senescence remains unclear. Here, we show that alteration of NFκB nuclear dynamics from oscillatory to sustained by depleting a negative feedback regulator of NFκB pathway, NFκB inhibitor alpha (IκBα), in the presence of tumor necrosis factor α (TNFα) promotes cellular senescence. Sustained NFκB activity enhanced inflammatory gene expression through increased NFκB‐DNA binding and slowed the cell cycle. IκBα protein was decreased under replicative or oxidative stress in vitro. Furthermore, a decrease in IκBα protein and an increase in DNA‐NFκB binding at the transcription start sites of age‐associated genes in aged mouse hearts suggested that nuclear NFκB dynamics may play a critical role in the progression of aging. Our study suggests that nuclear NFκB dynamics‐dependent epigenetic changes regulated over time in a living system, possibly through a decrease in IκBα, enhance the expression of inflammatory genes to advance the cells to a senescent state. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) are obligate mutualists that can enhance nutrition and growth of their plant hosts while providing protection against pathogens. AMF produce spores and hyphal networks that can carry thousands of nuclei in a continuous cytoplasm, with no evidence of sexual reproduction. This review examines the impact of genomic technologies on our view of AMF genetics and evolution. We highlight how the genetics, nuclear dynamics, and epigenetics of these prominent symbionts follow trends preserved in distant multinucleate fungal relatives. We also propose new avenues of research to improve our understanding of their nuclear biology and their intricate genetic interactions with plant hosts. [ABSTRACT FROM AUTHOR]

The DNA replication process needs to be coordinated with other DNA metabolism transactions and must eventually extend to the full genome, regardless of chromatin status, gene expression, secondary structures and DNA lesions. Completeness and accuracy of DNA replication are crucial to maintain genome integrity, limiting transformation in normal cells and offering targeting opportunities for proliferating cancer cells. DNA replication is thus tightly coordinated with chromatin dynamics and 3D genome architecture, and we are only beginning to understand the underlying molecular mechanisms. While much has recently been discovered on how DNA replication initiation is organised and modulated in different genomic regions and nuclear territories—the so-called "DNA replication program"—we know much less on how the elongation of ongoing replication forks and particularly the response to replication obstacles is affected by the local nuclear organisation. Also, it is still elusive how specific components of nuclear architecture participate in the replication stress response. Here, we review known mechanisms and factors orchestrating replication initiation, and replication fork progression upon stress, focusing on recent evidence linking genome organisation and nuclear architecture with the cellular responses to replication interference, and highlighting open questions and future challenges to explore this exciting new avenue of research. [ABSTRACT FROM AUTHOR]

We describe nuclear effects in structure functions of nuclei in DIS by means of a multiplicative factor β A (x) which differentiates the structure function of the bound nucleons from that of the free nucleons. Our analysis determines that β A (x) establishes a relation between the quark-gluon dynamics expressed by the bound nucleon structure functions and the nuclear dynamics as described by the well-known semi-empirical Bethe-Weizsäcker mass formula. This relation corroborates a connection between the underlying quark-gluon dynamics and the phenomenological nuclear dynamics. [ABSTRACT FROM AUTHOR]

The hyperbolic matrix method for the treatment of atomic and molecular nuclear dynamics is derived by means of the wave packet technique within the Born–Oppenheimer approach formalism. This method allows one to calculate the evolution of a wave packet by means of the product of usual matrices instead of the time propagation of matrix exponentials. We provide a detailed description of this method, considering Tully’s model as an example. We also show good agreement with the Landau–Zener model application.

Non alloyed carbon deoxidation can fundamentally solve the technical difficulty of fatigue failure of high‐quality bearing steel caused by inclusions. Herein, nonalloyed carbon deoxidation is presented with CO as a product, which can avoid the problem of residual inclusions. The thermodynamic and kinetic nucleation models of [C] deoxidation are constructed. The results suggest that a decrease in pCO strengthens the deoxidation ability of [C], and the [%O] balanced with [%C] shows multiple decreases. When pCO = 0.1 atm and [%C] = 0.5%, [%O] can be reduced to less than 10 ppm. However, from the results of the nucleation kinetic model, as pCO decreases, the critical radius r* increases, and the resistance of CO nucleation also increases. This results in difficulty of nucleation. Based on the nucleation kinetic model, the following C–O reaction mechanism is proposed: 1) [C] and [O] move to the reaction interface, 2) [C] + [O] = CO, forming a critical bubble nucleus, and 3) the newly formed CO diffuses continuously into the critical bubble, causing the bubble to grow and float away. Alternatively, the CO separates from the gas–liquid interface and enters the bubble, which floats away. [ABSTRACT FROM AUTHOR]

The nuclear playground in Southern Asia is marked by an exceptional level of complexity. A number of players; their disparate thinking on how to establish deterrence; nuclear dyads that elongate into strategic chains; inter-twining of nuclear issues with conventional, space, cyber realms; disparities in military capabilities; historical animosities accentuated by unresolved territorial conflicts; divides that spawn ideologies, religions and civilizational issues; all make for an immensely complex situation. The consequent regional nuclear dynamics has fair potential for crisis and arms race instability. As a way to address the regional nuclear challenges, the paper explores the character of Pakistan–India and China–India nuclear dyads along three specific axes: drivers of conflict; points of commonalities, similarities and differences; and implications of these for their nuclear stockpiles. Armed with this understanding, it then offers some policy recommendations to address the concomitant dangers.

Strong-field induced valence electron excitation is a common process in strong field interaction with atoms and molecules. In the case of polyatomic molecules, the effects of ionization from low-lying molecular orbitals and nuclear dynamics during the interaction can play critical roles for electron excitation. In this work, we investigate the involved molecular orbitals in the electron excitation of singly ionized acetylene in a strong laser field using alignment dependence and laser intensity dependence. Additionally, the involved nuclear dynamics during the electron excitation are identified from the difference in the kinetic energy release and the angular distribution of laser-induced dissociation with different pulse durations and intensities. The laser intensity dependence clearly shows the relative strength change of two excitation pathways in the measured momentum and angle-resolved distributions.

We report a measurement of electron momentum distributions of valence orbitals of cyclopentene employing symmetric noncoplanar (e,2e) kinematics at impact energies of 1200 and 1600 eV plus the binding energy. Experimental momentum profiles for individual ionization bands are obtained and compared with theoretical calculations considering nuclear dynamics by harmonic analytical quantum mechanical and thermal sampling molecular dynamics approaches. The results demonstrate that molecular vibrational motions including ring-puckering of this flexible cyclic molecule have obvious influences on the electron momentum profiles for the outer valence orbitals, especially in the low momentum region. For π∗-like molecular orbitals 3a′′, 2a′′, and 3a′, the impact-energy dependence of the experimental momentum profiles indicates a distorted wave effect. [ABSTRACT FROM AUTHOR]

Pericentromeric heterochromatin is mostly composed of repetitive DNA sequences prone to aberrant recombination. Cells have developed highly specialized mechanisms to enable 'safe' homologous recombination (HR) repair while preventing aberrant recombination in this domain. Understanding heterochromatin repair responses is essential to understanding the critical mechanisms responsible for genome integrity and tumor suppression. Here, we review the tools, approaches, and methods currently available to investigate double-strand break (DSB) repair in pericentromeric regions, and also suggest how technologies recently developed for euchromatin repair studies can be adapted to characterize responses in heterochromatin. With this ever-growing toolkit, we are witnessing exciting progress in our understanding of how the 'dark matter' of the genome is repaired, greatly improving our understanding of genome stability mechanisms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Viruses can modulate intracellular microenvironments, including membraneless organelles (MLOs). • HIV-1 infection induces the formation of nuclear CPSF6 condensates. • HIV-1 capsid and CPSF6 coexist inside HIV-MLOs and probably trigger their formation. • HIV-1 induced MLOs play key functions in the early steps of the viral life cycle. Viruses are obligate parasites that rely on their host's cellular machinery for replication. To facilitate their replication cycle, many viruses have been shown to remodel the cellular architecture by inducing the formation of membraneless organelles (MLOs). Eukaryotic cells have evolved MLOs that are highly dynamic, self-organizing microenvironments that segregate biological processes and increase the efficiency of reactions by concentrating enzymes and substrates. In the context of viral infections, MLOs can be utilized by viruses to complete their replication cycle. This review focuses on the pathway used by the HIV-1 virus to remodel the nuclear landscape of its host, creating viral/host niches that enable efficient viral replication. Specifically, we discuss how the interaction between the HIV-1 capsid and the cellular factor CPSF6 triggers the formation of nuclear MLOs that support nuclear reverse transcription and viral integration in favored regions of the host chromatin. This review compiles current knowledge on the origin of nuclear HIV-MLOs and their role in early post-nuclear entry steps of the HIV-1 replication cycle. [ABSTRACT FROM AUTHOR]

• Some arbuscular mycorrhizal (AM) fungal strains referred as AMF dikaryons carry thousands of nuclei originating from two parental strains. • The ratio of coexisting nucleotypes in AMF dikaryons is affected by abiotic factors. • The ratio of coexisting nucleotypes in AMF dikaryons is harmonized when the mycelium encounters multiple abiotic factors simultaneously. • The observed ratios are stable across conditions. Arbuscular mycorrhizal fungi (AMF) are widespread obligate root symbionts that assist plants in obtaining nutrients and protection against environmental stresses. In the model species Rhizophagus irregularis , heterokaryotic strains (AMF dikaryons) carry thousands of nuclei originating from two parental strains whose frequency varies depending on strains and host identity. Here, using digital droplet PCR, we demonstrate that surrounding abiotic factors (temperature, phosphorus, and pH) also change the nuclear dynamics of such strains in root organ cultures. Furthermore, when spatially separated portions of the AMF mycelium grow under different abiotic conditions, all the produced spores carry highly similar nuclear ratios. Overall, these findings demonstrate that abiotic stressors impact the nuclear organization of a widespread group of multinucleate plant symbionts, and reveal remarkable mechanisms of nuclear ratio harmonization across the mycelium in these prominent symbionts. [ABSTRACT FROM AUTHOR]