A Mutation in Amino Acid Permease AAP6 Reduces the Amino Acid Content of the Arabidopsis Sieve Elements but Leaves Aphid Herbivores Unaffected.

The aim of this study was to investigate the role of the amino acid permease gene AAP6 in regulating phloem amino acid composition and then to determine the effects of this altered diet on aphid performance. A genotype of Arabidopsis thaliana (L.) was produced in which the function of the amino acid permease gene AAP6 (At5g49630) was abolished. Plants homozygous for the insertionally inactivated AAP6 gene had a significantly larger mean rosette width than the wild type and a greater number of cauline leaves. Seeds from the aap6 mutant were also significantly larger than those from the wild-type plants. Sieve element (SE) sap was collected by aphid stylectomy and the amino acids derivatized, separated, and quantified using Capillary Electrophoresis with Laser Induced Fluorescence (CE-LIF). In spite of the large variation across samples, the total amino acid concentration of SE sap of the aap6 mutant plants was significantly lower than that of the wild-type plants. The concentrations of lysine, phenylalanine, leucine, and aspartic acid were all significantly lower in concentration in the aap6 mutant plants compared with wild-type plants. This is the first direct demonstration of a physiological role for an amino acid transporter in regulating SE composition in vivo. The amino acid availability in sieve element sap is thought to be the major limiting factor for aphid growth and reproduction. Despite the changes in their diet, the aphid Myzus persicae(Sulzer) displayed only small changes in feeding behaviour on mutant plants when measured using the Electronic Penetration Graph (EPG) technique. Salivation by the aphid into the SE (E1 phase) was increased on mutant plants but there was no significant effect on other feeding EPG behaviours, or in the rate of honeydew production. Consistent with the small effect on aphid feeding behaviour, there was only a small effect of reduced sieve element amino acid concentration on aphid reproduction. The data are discussed in relation to the regulation of phloem composition and the role of phloem amino acids in regulating aphid performance

Host specificity and species colouration mediate the regional decline of nocturnal moths in central European forests

The high diversity of insects has limited the volume of long-term community data with a high taxonomic resolution and considerable geographic replications, especially in forests. Therefore, trends and causes of changes are poorly understood. Here we analyse trends in species richness, abundance and biomass of nocturnal macro moths in three quantitative data sets collected over four decades in forests in southern Germany. Two local data sets, one from coppiced oak forests and one from high oak forests included 125K and 48K specimens from 559 and 532 species, respectively. A third regional data set, representing all forest types in the temperate zone of central Europe comprised 735K specimens from 848 species. Generalized additive mixed models revealed temporal declines in species richness (−38%), abundance (−53%) and biomass (−57%) at the regional scale. These were more pronounced in plant host specialists and in dark coloured species. In contrast, the local coppiced oak forests showed an increase, in species richness (+62%), while the high oak forests showed no clear trends. Left and right censoring as well as cross validation confirmed the robustness of the analyses, which led to four conclusions. First, the decline in insects appears in hyper diverse insect groups in forests and affects species richness, abundance and biomass. Second, the pronounced decline in host specialists suggests habitat loss as an important driver of the observed decline. Third, the more severe decline in dark species might be an indication of global warming as a potential driver. Fourth, the trends in coppiced oak forests indicate that maintaining complex and diverse forest ecosystems through active management may be a promising conservation strategy in order to counteract negative trends in biodiversity, alongside rewilding approaches

Direct Observation of Martensitic Phase-Transformation Dynamics in Iron by 4D Single-Pulse Electron Microscopy

The in situ martensitic phase transformation of iron, a complex solid-state transition involving collective atomic displacement and interface movement, is studied in real time by means of four-dimensional (4D) electron microscopy. The iron nanofilm specimen is heated at a maximum rate of ∼10^(11) K/s by a single heating pulse, and the evolution of the phase transformation from body-centered cubic to face-centered cubic crystal structure is followed by means of single-pulse, selected-area diffraction and real-space imaging. Two distinct components are revealed in the evolution of the crystal structure. The first, on the nanosecond time scale, is a direct martensitic transformation, which proceeds in regions heated into the temperature range of stability of the fcc phase, 1185−1667 K. The second, on the microsecond time scale, represents an indirect process for the hottest central zone of laser heating, where the temperature is initially above 1667 K and cooling is the rate-determining step. The mechanism of the direct transformation involves two steps, that of (barrier-crossing) nucleation on the reported nanosecond time scale, followed by a rapid grain growth typically in ∼100 ps for 10 nm crystallites

The acquisition of Sign Language: The impact of phonetic complexity on phonology

Research into the effect of phonetic complexity on phonological acquisition has a long history in spoken languages. This paper considers the effect of phonetics on phonological development in a signed language. We report on an experiment in which nonword-repetition methodology was adapted so as to examine in a systematic way how phonetic complexity in two phonological parameters of signed languages — handshape and movement — affects the perception and articulation of signs. Ninety-one Deaf children aged 3–11 acquiring British Sign Language (BSL) and 46 hearing nonsigners aged 6–11 repeated a set of 40 nonsense signs. For Deaf children, repetition accuracy improved with age, correlated with wider BSL abilities, and was lowest for signs that were phonetically complex. Repetition accuracy was correlated with fine motor skills for the youngest children. Despite their lower repetition accuracy, the hearing group were similarly affected by phonetic complexity, suggesting that common visual and motoric factors are at play when processing linguistic information in the visuo-gestural modality

"Oh! What a tangled web we weave": Englishness, communicative leisure, identity work and the cultural web of the English folk morris dance scene

In this paper, we consider the relationship between Englishness and the English folk morris dance scene, considering how the latter draws from and reinforces the former. Englishness is considered within the context of the cultural web; a tool more often applied to business management but linked to a sociological viewpoint here. By doing so, we draw the connections between this structured business model and the cultural identity of Englishness. Then, we use the framework of the cultural web and theories of leisure, culture and identity to understand how morris dancers see their role as dancers and ‘communicative leisure’ agents in consciously defending Englishness, English traditions and inventions, the practices and traditions of folk and morris, and the various symbolic communities they inhabit. We argue that most morris dancers in our research become and maintain their leisured identities as dancers because they are attracted to the idea of tradition – even if that tradition is invented and open to change

Epigenetic Differences in Cortical Neurons from a Pair of Monozygotic Twins Discordant for Alzheimer's Disease

DNA methylation [1], [2] is capable of modulating coordinate expression of large numbers of genes across many different pathways, and may therefore warrant investigation for their potential role between genes and disease phenotype. In a rare set of monozygotic twins discordant for Alzheimer's disease (AD), significantly reduced levels of DNA methylation were observed in temporal neocortex neuronal nuclei of the AD twin. These findings are consistent with the hypothesis that epigenetic mechanisms may mediate at the molecular level the effects of life events on AD risk, and provide, for the first time, a potential explanation for AD discordance despite genetic similarities

Bullying Victimisation, Internalising Symptoms, and Conduct Problems in South African Children and Adolescents: A Longitudinal Investigation

Bullying victimisation has been prospectively linked with mental health problems among children and adolescents in longitudinal studies in the developed world. However, research from the developing world, where adolescents face multiple risks to social and emotional development, has been limited by cross-sectional designs. This is the first longitudinal study of the psychological impacts of bullying victimisation in South Africa. The primary aim was to examine prospective relationships between bullying victimisation and internalising and externalising symptoms in South African youth. Secondary aims were to examine gender and age-related differences in experiences of bullying victimisation. Children and adolescents (10–17 years, 57 % female, n = 3,515) from high HIV-prevalent (>30 %) communities in South Africa were interviewed and followed-up 1 year later (97 % retention). Census enumeration areas were randomly selected from urban and rural sites in two provinces and door-to-door sampling included all households with a resident child/adolescent. Exposure to multiple experiences of bullying victimisation at baseline predicted internalising symptoms and conduct problems 1 year later. Additionally, baseline mental health scores predicted later bullying victimisation, demonstrating bi-directionality of relationships between bullying victimisation and mental health outcomes in this sample. Expected gender differences in physical, verbal, and relational bullying victimisation were evident and predicted declines in bullying victimisation over time were observed. In the developed world, school-based anti-bullying programmes have been shown to be effective in reducing bullying and victimisation. Anti-bullying programmes should be implemented and rigorously evaluated in South Africa, as this may promote improved mental health among South African children and adolescents

Morris dancers, matriarchs and paperbacks:Doing the village in contemporary Britain

To call a place rural is to categorize it as a particular kind of place and, often, to presume that particular kinds of being innately occur there. Over the past 20 years, however, trends in British rural studies have problematized easy ascription; this article is an ethnographic contribution within those trends. If it is no longer adequate to read the rural as a container for being, then, as I contend here, rurality can be explored anew through doing. I draw upon David Matless’s (1994) frame of ‘doing the village’ representationally, and amplify it to include concepts of place as representational and relational. I thus use ‘doing’ to read the multiple ways in which diverse residents in a Northern England village engage with both their real locality and with nationally shared rural imaginings