It is textbook knowledge that inheritance of traits is governed by genetics, and that the epigenetic modifications an organism acquires are largely reset between generations. Recently, however, ...transgenerational epigenetic inheritance has emerged as a rapidly growing field, providing evidence suggesting that some epigenetic changes result in persistent phenotypes across generations. Here, we survey some of the most recent examples of transgenerational epigenetic inheritance in animals, ranging from Caenorhabditis elegans to humans, and describe approaches and limitations to studying this phenomenon. We also review the current body of evidence implicating chromatin modifications and RNA molecules in mechanisms underlying this unconventional mode of inheritance and discuss its evolutionary implications.
This paper investigates the market's reaction to U.K. insider transactions and analyzes whether the reaction depends on the firm's ownership. We present three major findings. First, differences in ...regulation between the U.K. and United States, in particular the speedier reporting of trades in the U.K., may explain the observed larger abnormal returns in the U.K. Second, ownership by directors and outside shareholders has an impact on the abnormal returns. Third, it is important to adjust for news released before directors' trades. In particular, trades preceded by news on mergers and acquisitions and CEO replacements contain significantly less information.
Polyaniline–silver nanocomposite has been synthesized successfully by the chemical oxidative polymerization of aniline with ammonium peroxydisulphate as an initiator in presence of negatively charged ...silver nanoparticles. Silver nanoparticles are prepared by standard citrate reduction method. TEM, SEM, XRD, FTIR, TGA, DSC, optical absorption and photoluminescence studies are done for the morphological, structural, thermal and optical characterization of the polyaniline nanocomposite. From the TEM and SEM image, it is observed that nanoparticles are well dispersed in the polyaniline matrix. XRD pattern shows that polyaniline is amorphous, but peaks present in XRD pattern in polymer nanocomposites are for silver nanoparticles. TGA and DSC results show that polyaniline silver nanocomposite is more crystalline and more thermally stable. A surface plasmon absorption band is obtained from the optical absorption at 380
nm, which indicates that silver nanoparticles are present in the polyaniline matrix. The optical band gap of nanocomposite decreases with increasing content of silver nanoparticles. An enhancement in photoluminescence has been observed in polyaniline–silver nanocomposite than that in pure polyaniline. The electrical conductivity of polyaniline–silver nanocomposite increases with increase in silver nanoparticle content than that of pure polyaniline. This is a simple way by which optical and electrical properties of polyaniline may be enhanced by doping with suitable nanoparticles.
Ultralow thermal conductivity draws great attention in a variety of fields of applications such as thermoelectrics and thermal barrier coatings. Herein, the crystal structure and transport properties ...of Cu4TiSe4 are reported. Cu4TiSe4 is a unique example of a non‐toxic and low‐cost material that exhibits a lattice ultra‐low thermal conductivity of 0.19 Wm−1 K−1 at room temperature. The main contribution to the unusually low thermal conductivity is connected with the atomic lattice and its dynamics. This ultralow value of lattice thermal conductivity (kL) can be attributed to the presence of the localized modes of Cu, which partially hybridize with the Se atoms, which in turn leads to avoidance of crossing of acoustic phonon modes that reach the zone boundary with a reduced frequency. Like a phonon glass electron crystal, Cu4TiSe4 could also open a route to efficient thermoelectric materials, even, with chalcogenides of relatively high electrical resistivity and a large band gap, provided that their structures offer a sublattice with lightly bound cations.
Cu4TiSe4 is a unique example of a non‐toxic and low‐cost material that exhibits a lattice ultra‐low thermal conductivity of 0.19 Wm−1 K−1 at room temperature. The main contribution to the unusually low thermal conductivity is connected with the atomic lattice and its dynamics.
Protein kinase M-ζ (PKM-ζ) is a constitutively active form of atypical protein kinase C that is exclusively expressed in the brain and implicated in the maintenance of long-term memory. Most studies ...that support a role for PKM-ζ in memory maintenance have used pharmacological PKM-ζ inhibitors such as the myristoylated zeta inhibitory peptide (ZIP) or chelerythrine. Here we use a genetic approach and target exon 9 of the Prkcz gene to generate mice that lack both protein kinase C-ζ (PKC-ζ) and PKM-ζ (Prkcz(-/-) mice). Prkcz(-/-) mice showed normal behaviour in a cage environment and in baseline tests of motor function and sensory perception, but displayed reduced anxiety-like behaviour. Notably, Prkcz(-/-) mice did not show deficits in learning or memory in tests of cued fear conditioning, novel object recognition, object location recognition, conditioned place preference for cocaine, or motor learning, when compared with wild-type littermates. ZIP injection into the nucleus accumbens reduced expression of cocaine-conditioned place preference in Prkcz(-/-) mice. In vitro, ZIP and scrambled ZIP inhibited PKM-ζ, PKC-ι and PKC-ζ with similar inhibition constant (K(i)) values. Chelerythrine was a weak inhibitor of PKM-ζ (K(i) = 76 μM). Our findings show that absence of PKM-ζ does not impair learning and memory in mice, and that ZIP can erase reward memory even when PKM-ζ is not present.
This paper contributes to our understanding of managers' motivations for initiating the sale of their company. Using a sample of 1098 publicly-listed US target firms with completed deals, we show ...that deals initiated by the target firm rather than by outside bidders have higher CEO ownership. Furthermore, CEOs are motivated to offer their firms for sale also by higher golden parachutes, stock and stock option grants prior to takeovers. Our results suggest that motivated CEOs participate actively in deal negotiations, rather than being bribed not to resist the deal. In target-initiated deal firms, CEO ownership and equity grants are also positively correlated with takeover premiums.
•The paper analyzes managerial motivation for merger deal initiation.•CEO ownership increases the odds of target deal initiation.•CEOs are motivated to sell and actively participate in deal negotiations.•Takeover premiums in target-initiated deals increase with CEO motivation.
The knowledge about pressure–volume–temperature–composition (PVTxy) properties plays an important role in the design and operation of many processes involved in CO₂ capture and storage (CCS) systems. ...A literature survey was conducted on both the available experimental data and the theoretical models associated with the thermodynamic properties of CO₂ mixtures within the operation window of CCS. Some gaps were identified between available experimental data and requirements of the system design and operation. The major concerns are: for the vapour–liquid equilibrium, there are no data about CO₂/COS and few data about the CO₂/N₂O₄ mixture. For the volume property, there are no published experimental data for CO₂/O₂, CO₂/CO, CO₂/N₂O₄, CO₂/COS and CO₂/NH₃ and the liquid volume of CO₂/H₂. The experimental data available for multi-component CO₂ mixtures are also scarce. Many equations of state are available for thermodynamic calculations of CO₂ mixtures. The cubic equations of state have the simplest structure and are capable of giving reasonable results for the PVTxy properties. More complex equations of state such as Lee–Kesler, SAFT and GERG typically give better results for the volume property, but not necessarily for the vapour–liquid equilibrium. None of the equations of state evaluated in the literature show any clear advantage in CCS applications for the calculation of all PVTxy properties. A reference equation of state for CCS should, thus, be a future goal.
The accelerated diffusion of ions along grain boundaries in ionic solids may occur along two possible paths: (a) the interface core (IC), as known for metals; and (b) space‐charge layers (SCLs), ...located adjacent to the core, in which the point defects responsible for diffusion are accumulated. In this study, we examined whether it is possible, on the basis of diffusion profiles, to discriminate between IC and SCL diffusion paths. Taking cation diffusion along grain boundaries in MO2 oxides as our example system, we used finite‐element‐method (FEM) calculations to obtain cation diffusion profiles for various combinations of fast grain‐boundary diffusion along the two possible diffusion paths. Three characteristics of the grain‐boundary feature in diffusion profiles were investigated: the quantitative description of this grain‐boundary “tail”, its dependence on diffusion time, and its dependence on temperature (activation enthalpy). For all calculated diffusion profiles, with varying ratios of IC to SCL diffusion, no criterion was found that allowed the dominant diffusion path to be identified. Consideration of the activation enthalpies, however, may provide an indication of the dominant path: If the activation energy for grain‐boundary diffusion approaches or equals the activation enthalpy for bulk diffusion, one may conclude that SCL diffusion dominates.
Chromatin modifiers regulate lifespan in several organisms, raising the question of whether changes in chromatin states in the parental generation could be incompletely reprogrammed in the next ...generation and thereby affect the lifespan of descendants. The histone H3 lysine 4 trimethylation (H3K4me3) complex, composed of ASH-2, WDR-5 and the histone methyltransferase SET-2, regulates Caenorhabditis elegans lifespan. Here we show that deficiencies in the H3K4me3 chromatin modifiers ASH-2, WDR-5 or SET-2 in the parental generation extend the lifespan of descendants up until the third generation. The transgenerational inheritance of lifespan extension by members of the ASH-2 complex is dependent on the H3K4me3 demethylase RBR-2, and requires the presence of a functioning germline in the descendants. Transgenerational inheritance of lifespan is specific for the H3K4me3 methylation complex and is associated with epigenetic changes in gene expression. Thus, manipulation of specific chromatin modifiers only in parents can induce an epigenetic memory of longevity in descendants.
Stem cells are one of the foundational evolutionary novelties that allowed the independent emergence of multicellularity in the plant and animal lineages. In plants, the homeodomain (HD) ...transcription factor WUSCHEL (WUS) is essential for the maintenance of stem cells in the shoot apical meristem. WUS has been reported to bind to diverse DNA motifs and to act as transcriptional activator and repressor. However, the mechanisms underlying this remarkable behavior have remained unclear. Here, we quantitatively delineate WUS binding to three divergent DNA motifs and resolve the relevant structural underpinnings. We show that WUS exhibits a strong binding preference for TGAA repeat sequences, while retaining the ability to weakly bind to TAAT elements. This behavior is attributable to the formation of dimers through interactions of specific residues in the HD that stabilize WUS DNA interaction. Our results provide a mechanistic basis for dissecting WUS dependent regulatory networks in plant stem cell control.
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