Epigenetic control of Epstein–Barr virus transcription – relevance to viral life cycle?

DNA methylation normally leads to silencing of gene expression but Epstein–Barr virus (EBV) provides an exception to the epigenetic paradigm. DNA methylation is absolutely required for the expression of many viral genes. Although the viral genome is initially un-methylated in newly infected cells, it becomes extensively methylated during the establishment of viral latency. One of the major regulators of EBV gene expression is a viral transcription factor called Zta (BZLF1, ZEBRA, Z) that resembles the cellular AP1 transcription factor. Zta recognizes at least 32 variants of a 7-nucleotide DNA sequence element, the Zta-response element (ZRE), some of which contain a CpG motif. Zta only binds to the latter class of ZREs in their DNA-methylated form, whether they occur in viral or cellular promoters and is functionally relevant for the activity of these promoters. The ability of Zta to interpret the differential DNA methylation of the viral genome is paramount for both the establishment of viral latency and the release from latency to initiate viral replication

A population of immature cerebellar parallel fibre synapses are insensitive to adenosine but are inhibited by hypoxia

The purine adenosine plays an important role in a number of physiological and pathological processes and is neuroprotective during hypoxia and ischemia. The major effect of adenosine is to suppress network activity via the activation of A1 receptors. Here we report that in immature cerebellar slices, the activation of A1 receptors has variable effects on parallel fibre synaptic transmission, ranging from zero depression to an almost complete abolition of transmission. Concentration–response curves suggest that the heterogeneity of inhibition stems from differences in A1 receptor properties which could include coupling to downstream effectors. There is less variation in the effects of adenosine at parallel fibre synapses in slices from older rats and thus adenosine signalling appears developmentally regulated. In the cerebellum, hypoxia increases the concentration of extracellular adenosine leading to the activation of A1 receptors (at adenosine-sensitive parallel fibre synapses) and the suppression of glutamate release. It would be predicted that the synapses that were insensitive to adenosine would be less depressed by hypoxia and thus maintain function during metabolic stress. However those synapses which were insensitive to adenosine were rapidly inhibited by hypoxia via a mechanism which was not reversed by blocking A1 receptors. Thus another mechanism must be responsible for the hypoxia-mediated depression at these synapses. These different mechanisms of depression may be important for cell survival and for maintenance of cerebellar function following oxygen starvation

Volunteer tourism: Evidence of cathartic tourist experiences

The study involved in-depth interviews with participants of an Australian non-government organization (NGO) that organizes projects in which young volunteers aged between 17 and 26 years from Australia and New Zealand participate in welfare projects with partner NGOs in developing countries. The welfare projects provide on the ground assistance to communities; these may not lead to longer-term sustainable development through longer-term skills training but engage the volunteers and community in a mutual exchange. Typically, participants will be engaged in short term courses in health and hygiene, micro-enterprise management skills, assisting in community health projects, community service with children with disabilities or orphans, painting, construction of school playgrounds and classrooms, guest teaching in schools, cultural exchange and disaster relief. The Australian NGO provides no financial assistance for participants; it primarily organizes and facilitates the travel, project and community work. Each project lasts between two and four weeks and are thus typically short-term in duration. As such, participants can be considered 'shallow volunteer tourists' (Callanan and Thomas 2005)

Electrochemistry of ferrocenylphosphines FcCH₂PR₂ (Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄); R=Ph, CH₂OH and CH₂CH₂CN), and some phosphine oxide, phosphine sulfide, phosphonium and metal complex derivatives

Electrochemical studies of the free ferrocenylphosphine ligands FcCH₂PR₂ (Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄); R=Ph, CH₂OH and CH₂CH₂CN) and some phosphine oxide, phosphine sulfide, phosphonium and metal derivatives are described. The free ligands exhibit complex voltammetric responses due to participation of the phosphorus lone pair in the redox reactions. Uncomplicated ferrocene-based redox chemistry is observed for PV derivatives and when the ligands are coordinated in complexes cis-PtCl₂[FcCH₂P(CH₂OH)₂], PdCl₂[FcCH₂P(CH₂OH)₂], [Au{FcCH₂P(CH₂OH)₂}₂]Cl, RuCl₂(η⁶-C₁₀H₁₄)[FcCH₂P(CH₂OH)₂] and RuCl₂(η⁶-C₁₀H₁₄)(FcCH₂PPh₂). The reaction pathways of the free ligands after one-electron oxidation have been examined in detail using voltammetry, NMR spectroscopy and electrospray mass spectrometry. Direct evidence for formation of a P---P bonded product is presented

What does successful social prescribing look like? Mapping meaningful outcomes

This study aimed to investigate and collate all the outcomes that are being experienced in link worker based social prescribing schemes. We found this reflects a large evidence gap where research money needs to be invested. Data from this study highlighted that VCSE organisations engaged with social prescribing are not receiving full attribution for their contribution to improving the health and wellbeing of people. Within the literature, there are a range of reports and research articles that support the use of community organisations and services. Little of this knowledge or impact, however, is contextualised within the terms of link worker based social prescribing schemes

Self-Similar Force-Free Wind From an Accretion Disk

We consider a self-similar force-free wind flowing out of an infinitely thin disk located in the equatorial plane. On the disk plane, we assume that the magnetic stream function $P$ scales as $P\propto R^\nu$, where $R$ is the cylindrical radius. We also assume that the azimuthal velocity in the disk is constant: $v_\phi = Mc$, where $M<1$ is a constant. For each choice of the parameters $\nu$ and $M$, we find an infinite number of solutions that are physically well-behaved and have fluid velocity $\leq c$ throughout the domain of interest. Among these solutions, we show via physical arguments and time-dependent numerical simulations that the minimum-torque solution, i.e., the solution with the smallest amount of toroidal field, is the one picked by a real system. For $\nu \geq 1$, the Lorentz factor of the outflow increases along a field line as \gamma \approx M(z/\Rfp)^{(2-\nu)/2} \approx R/R_{\rm A}, where \Rfp is the radius of the foot-point of the field line on the disk and R_{\rm A}=\Rfp/M is the cylindrical radius at which the field line crosses the Alfven surface or the light cylinder. For $\nu < 1$, the Lorentz factor follows the same scaling for z/\Rfp < M^{-1/(1-\nu)}, but at larger distances it grows more slowly: \gamma \approx (z/\Rfp)^{\nu/2}. For either regime of $\nu$, the dependence of $\gamma$ on $M$ shows that the rotation of the disk plays a strong role in jet acceleration. On the other hand, the poloidal shape of a field line is given by z/\Rfp \approx (R/\Rfp)^{2/(2-\nu)} and is independent of $M$. Thus rotation has neither a collimating nor a decollimating effect on field lines, suggesting that relativistic astrophysical jets are not collimated by the rotational winding up of the magnetic field.Comment: 21 pages, 15 figures, accepted to MNRA

Prey aggregation is an effective olfactory predator avoidance strategy

Predator–prey interactions have a major effect on species abundance and diversity, and aggregation is a well-known anti-predator behaviour. For immobile prey, the effectiveness of aggregation depends on two conditions: (a) the inability of the predator to consume all prey in a group and (b) detection of a single large group not being proportionally easier than that of several small groups. How prey aggregation influences predation rates when visual cues are restricted, such as in turbid water, has not been thoroughly investigated. We carried out foraging (predation) experiments using a fish predator and (dead) chironomid larvae as prey in both laboratory and field settings. In the laboratory, a reduction in visual cue availability (in turbid water) led to a delay in the location of aggregated prey compared to when visual cues were available. Aggregated prey suffered high mortality once discovered, leading to better survival of dispersed prey in the longer term. We attribute this to the inability of the dead prey to take evasive action. In the field (where prey were placed in feeding stations that allowed transmission of olfactory but not visual cues), aggregated (large groups) and semi-dispersed prey survived for longer than dispersed prey—including long termsurvival. Together, our results indicate that similar to systems where predators hunt using vision, aggregation is an effective anti-predator behaviour for prey avoiding olfactory predators

Olfactory cue use by three-spined sticklebacks foraging in turbid water: prey detection or prey location?

Foraging, when senses are limited to olfaction, is composed of two distinct stages: the detection of prey and the location of prey. While specialist olfactory foragers are able to locate prey using olfactory cues alone, this may not be the case for foragers that rely primarily on vision. Visual predators in aquatic systems may be faced with poor visual conditions such as natural or human-induced turbidity. The ability of visual predators to compensate for poor visual conditions by using other senses is not well understood, although it is widely accepted that primarily visual fish, such as three-spined sticklebacks, Gasterosteus aculeatus, can detect and use olfactory cues for a range of purposes. We investigated the ability of sticklebacks to detect the presence of prey and to locate prey precisely, using olfaction, in clear and turbid (two levels) water. When provided with only a visual cue, or only an olfactory cue, sticklebacks showed a similar ability to detect prey, but a combination of these cues improved their performance. In open-arena foraging trials, a dispersed olfactory cue added to the water (masking cues from the prey) improved foraging success, contrary to our expectations, whereas activity levels and swimming speed did not change as a result of olfactory cue availability. We suggest that olfaction functions to allow visual predators to detect rather than locate prey and that olfactory cues have an appetitive effect, enhancing motivation to forage