A partially sex-reversed giant kelp sheds light into the mechanisms of sexual differentiation in a UV sexual system

In UV sexual systems, sex is determined during the haploid phase of the life cycle and males have a V chromosome whereas females have a U chromosome. Previous work in the brown alga Ectocarpus revealed that the V chromosome has a dominant role in male sex determination and suggested that the female developmental programme may occur by 'default'. Here, we describe the identification of a genetically male giant kelp strain presenting phenotypic features typical of a female, despite lacking the U-specific region. The conversion to the female developmental programme is however incomplete, because gametes of this feminized male are unable to produce the sperm-attracting pheromone lamoxirene. We identify the transcriptomic patterns underlying the male and female specific developmental programmes, and show that the phenotypic feminization is associated with both feminization and de-masculinization of gene expression patterns. Importantly, the feminization phenotype was associated with dramatic downregulation of two V-specific genes including a candidate male-determining gene. Our results reveal the transcriptional changes associated with sexual differentiation in a UV system, and contribute to disentangling the role of sex-linked and autosomal gene expression in the initiation of sex-specific developmental programmes. Overall, the data presented here imply that the U-specific region is not required to initiate the female developmental programme, but is critical to produce fully functional eggs, arguing against the idea that female is the 'default' sex in this species

Parallel Microbial Ecology of Pasteuria and Nematode Species in Scottish Soils

Copyright © 2020 Orr, Neilson, Freitag, Roberts, Davies, Blok and Cock.Pasteuria spp. are endospore forming bacteria which act as natural antagonists to many of the most economically significant plant parasitic nematodes (PPNs). Highly species-specific nematode suppression may be observed in soils containing a sufficiently high density of Pasteuria spp. spores. This suppression is enacted by the bacteria via inhibition of root invasion and sterilization of the nematode host. Molecular methods for the detection of Pasteuria spp. from environmental DNA (eDNA) have been described; however, these methods are limited in both scale and in depth. We report the use of small subunit rRNA gene metabarcoding to profile Pasteuria spp. and nematode communities in parallel. We have investigated Pasteuria spp. population structure in Scottish soils using eDNA from two sources: soil extracted DNA from the second National Soil Inventory of Scotland (NSIS2); and nematode extracted DNA collected from farms in the East Scotland Farm Network (ESFN). We compared the Pasteuria spp. community culture to both nematode community structure and the physiochemical properties of soils. Our results indicate that Pasteuria spp. populations in Scottish soils are broadly dominated by two sequence variants. The first of these aligns with high identity to Pasteuria hartismeri, a species first described parasitizing Meloidogyne ardenensis, a nematode parasite of woody and perennial plants in northern Europe. The second aligns with a Pasteuria-like sequence which was first recovered from a farm near Edinburgh which was found to contain bacterial feeding nematodes and Pratylenchus spp. encumbered by Pasteuria spp. endospores. Further, soil carbon, moisture, bulk density, and pH showed a strong correlation with the Pasteuria spp. community composition. These results indicate that metabarcoding is appropriate for the sensitive, specific, and semi-quantitative profiling of Pasteuria species from eDNA.Peer reviewe

Towards a Proof Theory of G\"odel Modal Logics

Analytic proof calculi are introduced for box and diamond fragments of basic modal fuzzy logics that combine the Kripke semantics of modal logic K with the many-valued semantics of G\"odel logic. The calculi are used to establish completeness and complexity results for these fragments

An aphid RNA transcript migrates systemically within plants and is a virulence factor

Aphids are sap-feeding insects that colonize a broad range of plant species and often cause feeding damage and transmit plant pathogens, including bacteria, viruses, and viroids. These insects feed from the plant vascular tissue, predominantly the phloem. However, it remains largely unknown how aphids, and other sap-feeding insects, establish intimate long-term interactions with plants. To identify aphid virulence factors, we took advantage of the ability of the green peach aphid Myzus persicae to colonize divergent plant species. We found that a M. persicae clone of near-identical females established stable colonies on nine plant species of five representative plant eudicot and monocot families that span the angiosperm phylogeny. Members of the novel aphid gene family Ya are differentially expressed in aphids on the nine plant species and are coregulated and organized as tandem repeats in aphid genomes. Aphids translocate Ya transcripts into plants, and some transcripts migrate to distal leaves within several plant species. RNAi-mediated knockdown of Ya genes reduces M. persicae fecundity, and M. persicae produces more progeny on transgenic plants that heterologously produce one of the systemically migrating Ya transcripts as a long noncoding (lnc) RNA. Taken together, our findings show that beyond a range of pathogens, M. persicae aphids translocate their own transcripts into plants, including a Ya lncRNA that migrates to distal locations within plants, promotes aphid fecundity, and is a member of a previously undescribed host-responsive aphid gene family that operate as virulence factors

Dynamic fluorescence microscopy of cellular uptake of intercalating model drugs by ultrasound-activated microbubbles

The combination of ultrasound and microbubbles can facilitate cellular uptake of (model) drugs via transient permeabilization of the cell membrane. By using fluorescent molecules, this process can be studied conveniently with confocal fluorescence microscopy. This study aimed to investigate the relation between cellular uptake and fluorescence intensity increase of intercalating model drugs. SYTOX Green, an intercalating fluorescent dye that displays > 500-fold fluorescence enhancement upon binding to nucleic acids, was used as a model drug for ultrasound-induced cellular uptake. SYTOX Green uptake was monitored in high spatiotemporal resolution to qualitatively assess the relation between uptake and fluorescence intensity in individual cells. In addition, the kinetics of fluorescence enhancement were studied as a function of experimental parameters, in particular, laser duty cycle (DC), SYTOX Green concentration and cell line. Ultrasound-induced intracellular SYTOX Green uptake resulted in local fluorescence enhancement, spreading throughout the cell and ultimately accumulating in the nucleus during the 9-min acquisition. The temporal evolution of SYTOX Green fluorescence was substantially influenced by laser duty cycle: continuous laser (100 % DC) induced a 6.4-fold higher photobleaching compared to pulsed laser (3.3 % DC), thus overestimating the fluorescence kinetics. A positive correlation of fluorescence kinetics and SYTOX Green concentration was found, increasing from 0.6 x 10(-3) to 2.2 x 10(-3) s(-1) for 1 and 20 mu M, respectively. Finally, C6 cells displayed a 2.4-fold higher fluorescence rate constant than FaDu cells. These data show that the temporal behavior of intracellular SYTOX Green fluorescence enhancement depends substantially on nuclear accumulation and not just on cellular uptake. In addition, it is strongly influenced by the experimental conditions, such as the laser duty cycle, SYTOX Green concentration, and cell line

Discrimination of dark matter models in future experiments

Phenomenological aspects of simple dark matter models are studied. We discuss ways to discriminate the dark matter models in future experiments. We find that the measurements of the branching fraction of the Higgs boson into two photons and the electric dipole moment of the electron as well as the direct detection experiments are quite useful in discriminating particle models of dark matter. We also discuss the prospects of finding new particles in dark sector at the LHC/ILC.Comment: 39 pages, 20 figures; v3 a typo in the Appendix A.1 is correcte

The Body Dances: Carnival Dance and Organization

Building on the work of Pierre Bourdieu and Maurice Merleau-Ponty we seek to open up traditional categories of thought surrounding the relation `body-organization' and elicit a thought experiment: What happens if we move the body from the periphery to the centre? We pass the interlocking theoretical concepts of object-body/subject-body and habitus through the theoretically constructed empirical case of `carnival dance' in order to re-evaluate such key organizational concepts as knowledge and learning. In doing so, we connect with an emerging body of literature on `sensible knowledge'; knowledge that is produced and preserved within bodily practices. The investigation of habitual appropriation in carnival dance also allows us to make links between repetition and experimentation, and reflect on the mechanism through which the principles of social organization, whilst internalized and experienced as natural, are embodied so that humans are capable of spontaneously generating an infinite array of appropriate actions. This perspective on social and organizational life, where change and permanence are intricately interwoven, contrasts sharply with the dominant view in organization studies which juxtaposes change/ creativity and stability

PPAR-γ: a thrifty transcription factor

The peroxisome proliferator-activated receptor-γ (PPAR-γ) is a prototypical metabolic nuclear receptor that acts as a lipid sensor, integrating the homeostatic control of energy, lipid, and glucose metabolism. This perspective will highlight three lines of evidence which place PPAR-γ as a key player in a feed-forward pathway favoring differentiation and energy storage by adipocytes