Integration of sperm ncRNA-directed DNA methylation and DNA methylation-directed histone retention in epigenetic transgenerational inheritance

Background: Environmentally induced epigenetic transgenerational inheritance of pathology and phenotypic variation has been demonstrated in all organisms investigated from plants to humans. This non-genetic form of inheritance is mediated through epigenetic alterations in the sperm and/or egg to subsequent generations. Although the combined regulation of differential DNA methylated regions (DMR), non-coding RNA (ncRNA), and differential histone retention (DHR) have been shown to occur, the integration of these different epigenetic processes remains to be elucidated. The current study was designed to examine the integration of the different epigenetic processes. Results: A rat model of transiently exposed F0 generation gestating females to the agricultural fungicide vinclo-zolin or pesticide DDT (dichloro-diphenyl-trichloroethane) was used to acquire the sperm from adult males in the subsequent F1 generation offspring, F2 generation grand offspring, and F3 generation great-grand offspring. The F1 generation sperm ncRNA had substantial overlap with the F1, F2 and F3 generation DMRs, suggesting a potential role for RNA-directed DNA methylation. The DMRs also had significant overlap with the DHRs, suggesting potential DNA methylation-directed histone retention. In addition, a high percentage of DMRs induced in the F1 generation sperm were maintained in subsequent generations. Conclusions: Many of the DMRs, ncRNA, and DHRs were colocalized to the same chromosomal location regions. Observations suggest an integration of DMRs, ncRNA, and DHRs in part involve RNA-directed DNA methylation and DNA methylation-directed histone retention in epigenetic transgenerational inheritance

Red-Cockaded Woodpecker Cavity Tree Damage by Hurricane Rita: An Evaluation of Contributing Factors

Picoides borealis (Red-cockaded Woodpecker) is an endangered species inhabiting pine savannas of the southeastern United States. Because the intensity of hurricanes striking the southeastern United States is likely to increase as global temperatures rise, it is important to identify factors contributing to hurricane damage to Red-cockaded Woodpecker cavity-trees. Our objectives were to examine the effects of landscape-level factors on wind damage to cavity-trees and assess the relative risk of wind damage for different tree species and trees with different types of cavities. We evaluated wind damage to cavity-trees from Hurricane Rita on the Angelina, Sabine, and Davy Crockett national forests in eastern Texas. Basal area and number of cavity-trees in a cluster were identified as factors influencing the likelihood of damage to a cavity-tree. The likelihood of damage increased with decreasing basal area and an increasing number of cavity trees in a cluster. The increase in damage associated with an increase in the number of cavity trees in a cluster likely reflects an increase in cluster area with more cavity-trees and the maintenance of lower basal areas in clusters to meet the habitat requirements of Red-cockaded Woodpeckers. Therefore, increasing basal area is not a reasonable management option because clusters will become unsuitable for Red-cockaded Woodpeckers. A higher proportion of trees with natural cavities were damaged than trees with artificial cavities in all three forests. A higher proportion of Pinus echinata (Shortleaf Pine) cavity-trees were damaged than Pinus palustris (Longleaf Pine) or Pinus taeda (Loblolly Pine) cavitytrees. Longleaf Pine cavity-trees were more likely to snap at the cavity, compared to a higher likelihood of wind throw for Shortleaf and Loblolly Pine cavity-trees. Restoring Longleaf Pine habitat and allowing stands to develop under lower tree densities could decrease the likelihood of damage to cavity-trees and the impact of hurricanes on Red-cockaded Woodpeckers

Male-killing Wolbachia do not protect Drosophila bifasciata against viral infection.

BACKGROUND: Insect symbionts employ multiple strategies to enhance their spread through populations, and some play a dual role as both a mutualist and a reproductive manipulator. It has recently been found that this is the case for some strains of Wolbachia, which both cause cytoplasmic incompatibility and protect their hosts against viruses. Here, we carry out the first test as to whether a male-killing strain of Wolbachia also provides a direct benefit to its host by providing antiviral protection to its host Drosophila bifasciata. We infected flies with two positive sense RNA viruses known to replicate in a range of Drosophila species (Drosophila C virus and Flock House virus) and measure the rate of death in Wolbachia positive and negative host lines with the same genetic background. RESULTS: Both viruses caused considerable mortality to D. bifasciata flies, with Drosophila C virus killing 43% more flies than the uninfected controls and Flock House virus killing 78% more flies than the uninfected controls. However, viral induced mortality was unaffected by the presence of Wolbachia. CONCLUSION: In the first male-killing Wolbachia strain tested for antiviral effects, we found no evidence that it conferred protection against two RNA viruses. We show that although antiviral resistance is widespread across the Wolbachia phylogeny, the trait seems to have been lost or gained along some lineages. We discuss the potential mechanisms of this, and can seemingly discount protection against these viruses as a reason why this symbiont has spread through Drosophila populations.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Two-Species Annihilation with Drift: A Model with Continuous Concentration-Decay Exponents

We propose a model for diffusion-limited annihilation of two species, $A+B\to A$ or $B$, where the motion of the particles is subject to a drift. For equal initial concentrations of the two species, the density follows a power-law decay for large times. However, the decay exponent varies continuously as a function of the probability of which particle, the hopping one or the target, survives in the reaction. These results suggest that diffusion-limited reactions subject to drift do not fall into a limited number of universality classes.Comment: 10 pages, tex, 3 figures, also available upon reques

Statistics of Earthquakes in Simple Models of Heterogeneous Faults

Simple models for ruptures along a heterogeneous earthquake fault zone are studied, focussing on the interplay between the roles of disorder and dynamical effects. A class of models are found to operate naturally at a critical point whose properties yield power law scaling of earthquake statistics. Various dynamical effects can change the behavior to a distribution of small events combined with characteristic system size events. The studies employ various analytic methods as well as simulations.Comment: 4 pages, RevTex, 3 figures (eps-files), uses eps

Environmental induced transgenerational inheritance impacts systems epigenetics in disease etiology

Environmental toxicants have been shown to promote the epigenetic transgenerational inheritance of disease through exposure specific epigenetic alterations in the germline. The current study examines the actions of hydrocarbon jet fuel, dioxin, pesticides (permethrin and methoxychlor), plastics, and herbicides (glyphosate and atrazine) in the promotion of transgenerational disease in the great grand-offspring rats that correlates with specific disease associated differential DNA methylation regions (DMRs). The transgenerational disease observed was similar for all exposures and includes pathologies of the kidney, prostate, and testis, pubertal abnormalities, and obesity. The disease specific DMRs in sperm were exposure specific for each pathology with negligible overlap. Therefore, for each disease the DMRs and associated genes were distinct for each exposure generational lineage. Observations suggest a large number of DMRs and associated genes are involved in a specific pathology, and various environmental exposures influence unique subsets of DMRs and genes to promote the transgenerational developmental origins of disease susceptibility later in life. A novel multiscale systems biology basis of disease etiology is proposed involving an integration of environmental epigenetics, genetics and generational toxicology

Complete Exact Solution of Diffusion-Limited Coalescence, A + A -> A

Some models of diffusion-limited reaction processes in one dimension lend themselves to exact analysis. The known approaches yield exact expressions for a limited number of quantities of interest, such as the particle concentration, or the distribution of distances between nearest particles. However, a full characterization of a particle system is only provided by the infinite hierarchy of multiple-point density correlation functions. We derive an exact description of the full hierarchy of correlation functions for the diffusion-limited irreversible coalescence process A + A -> A.Comment: 4 pages, 2 figures (postscript). Typeset with Revte

Dental students' knowledge of and attitudes towards prescribing medication in Western Australia

ACKNOWLEDGEMENTThe authors would like to acknowledge UWA dental students for their time and valuable input. Open access publishing facilitated by The University of Western Australia, as part of the Wiley - The University of Western Australia agreement via the Council of Australian University Librarians. [Correction added on 14 May 2022, after first online publication: CAUL funding statement has been added.]Peer reviewedPublisher PD