Investigating the Relationship between Topology and Evolution in a Dynamic Nematode Odor Genetic Network

The relationship between biological network architectures and evolution is unclear. Within the phylum nematoda olfaction represents a critical survival tool. For nematodes, olfaction contributes to multiple processes including the finding of food, hosts, and reproductive partners, making developmental decisions, and evading predators. Here we examine a dynamic nematode odor genetic network to investigate how divergence, diversity, and contribution are shaped by network topology. Our findings describe connectivity frameworks and characteristics that correlate with molecular evolution and contribution across the olfactory network. Our data helps guide the development of a robust evolutionary description of the nematode odor network that may eventually aid in the prediction of interactive and functional qualities of novel nodes

Multiple lineage specific expansions within the guanylyl cyclase gene family

BACKGROUND: Guanylyl cyclases (GCs) are responsible for the production of the secondary messenger cyclic guanosine monophosphate, which plays important roles in a variety of physiological responses such as vision, olfaction, muscle contraction, homeostatic regulation, cardiovascular and nervous function. There are two types of GCs in animals, soluble (sGCs) which are found ubiquitously in cell cytoplasm, and receptor (rGC) forms which span cell membranes. The complete genomes of several vertebrate and invertebrate species are now available. These data provide a platform to investigate the evolution of GCs across a diverse range of animal phyla. RESULTS: In this analysis we located GC genes from a broad spectrum of vertebrate and invertebrate animals and reconstructed molecular phylogenies for both sGC and rGC proteins. The most notable features of the resulting phylogenies are the number of lineage specific rGC and sGC expansions that have occurred during metazoan evolution. Among these expansions is a large nematode specific rGC clade comprising 21 genes in C. elegans alone; a vertebrate specific expansion in the natriuretic receptors GC-A and GC-B; a vertebrate specific expansion in the guanylyl GC-C receptors, an echinoderm specific expansion in the sperm rGC genes and a nematode specific sGC clade. Our phylogenetic reconstruction also shows the existence of a basal group of nitric oxide (NO) insensitive insect and nematode sGCs which are regulated by O(2). This suggests that the primordial eukaryotes probably utilized sGC as an O(2 )sensor, with the ligand specificity of sGC later switching to NO which provides a very effective local cell-to-cell signalling system. Phylogenetic analysis of the sGC and bacterial heme nitric oxide/oxygen binding protein domain supports the hypothesis that this domain originated from a cyanobacterial source. CONCLUSION: The most salient feature of our phylogenies is the number of lineage specific expansions, which have occurred within the GC gene family during metazoan evolution. Our phylogenetic analyses reveal that the rGC and sGC multi-domain proteins evolved early in eumetazoan evolution. Subsequent gene duplications, tissue specific expression patterns and lineage specific expansions resulted in the evolution of new networks of interaction and new biological functions associated with the maintenance of organismal complexity and homeostasis

A comparative study of the molecular evolution of signalling pathway members across olfactory, gustatory and photosensory modalities

All sensory modalities serve a similar objective, which is to decode input by making predictions in time and space about an animal’s surroundings. The evolution of sensory modalities is driven by the need to shape effective behavioural outputs, and in turn increase survival. Throughout evolution, sensory systems have undergone a great deal of specialization; and even though some modalities are derived from unique origins within different phyla, they still exhibit many common design features (Strausfeld and Hildebrand 1999; Eisthen 2002; Jacobs et al. 2007). We now have detailed mechanistic data on how sensory systems operate within specific animals (Buck and Axel 1991; Chalasani et al. 2007; Sato et al. 2008; Wicher et al. 2008), however it is still not clear how sensory signalling pathways evolve at the molecular level, and whether these evolutionary mechanisms are shared between diverse taxa. Here we set out to investigate the molecular evolution of signalling pathway members across olfactory, gustatory, and photosensory modalities from very divergent phyla in an attempt to develop a model of molecular evolution for sensory systems. From our pairwise intraphylum analysis we found that sensory signalling pathways unusually undergo high levels of functional constraint that are higher than genomewide global levels of constraint, and this purifying selection is common within the very divergent taxa we examined. We also find that gene duplication events represent a conserved but heterogeneous driver of evolution within sensory signalling pathways. Taken together, we propose a ‘sessile’ mechanism of sensory signalling pathway evolution, which on one side facilitates bursts of gene duplication and relaxed selection and on the other side it is unusually anchored by high levels of selective constraint that preserves core sensory function

A comparative study of the molecular evolution of signalling pathway members across olfactory, gustatory and photosensory modalities

All sensory modalities serve a similar objective, which is to decode input by making predictions in time and space about an animal’s surroundings. The evolution of sensory modalities is driven by the need to shape effective behavioural outputs, and in turn increase survival. Throughout evolution, sensory systems have undergone a great deal of specialization; and even though some modalities are derived from unique origins within different phyla, they still exhibit many common design features (Strausfeld and Hildebrand 1999; Eisthen 2002; Jacobs et al. 2007). We now have detailed mechanistic data on how sensory systems operate within specific animals (Buck and Axel 1991; Chalasani et al. 2007; Sato et al. 2008; Wicher et al. 2008), however it is still not clear how sensory signalling pathways evolve at the molecular level, and whether these evolutionary mechanisms are shared between diverse taxa. Here we set out to investigate the molecular evolution of signalling pathway members across olfactory, gustatory, and photosensory modalities from very divergent phyla in an attempt to develop a model of molecular evolution for sensory systems. From our pairwise intraphylum analysis we found that sensory signalling pathways unusually undergo high levels of functional constraint that are higher than genomewide global levels of constraint, and this purifying selection is common within the very divergent taxa we examined. We also find that gene duplication events represent a conserved but heterogeneous driver of evolution within sensory signalling pathways. Taken together, we propose a ‘sessile’ mechanism of sensory signalling pathway evolution, which on one side facilitates bursts of gene duplication and relaxed selection and on the other side it is unusually anchored by high levels of selective constraint that preserves core sensory function

Interpreting text and image relations in violent extremist discourse: A mixed methods approach for big data analytics

This article presents a mixed methods approach for analysing text and image relations in violent extremist discourse. The approach involves integrating multimodal discourse analysis with data mining and information visualisation, resulting in theoretically informed empirical techniques for automated analysis of text and image relations in large datasets. The approach is illustrated by a study which aims to analyse how violent extremist groups use language and images to legitimise their views, incite violence, and influence recruits in online propaganda materials, and how the images from these materials are re-used in different media platforms in ways that support and resist violent extremism. The approach developed in this article contributes to what promises to be one of the key areas of research in the coming decades: namely the interdisciplinary study of big (digital) datasets of human discourse, and the implications of this for terrorism analysis and research

Polycyclic aromatic hydrocarbon processing in interstellar shocks

Context: PAHs appear to be an ubiquitous interstellar dust component but the effects of shocks waves upon them have never been fully investigated. Aims: To study the effects of energetic (~0.01-1 keV) ion (H, He and C) and electron collisions on PAHs in interstellar shock waves.Methods: We calculate the ion-PAH and electron-PAH nuclear and electronic interactions, above the threshold for carbon atom loss from a PAH, in 50-200 km/s shock waves in the warm intercloud medium. Results: Interstellar PAHs (Nc = 50) do not survive in shocks with velocities greater than 100 km/s and larger PAHs (Nc = 200) are destroyed for shocks with velocities greater/equal to 125 km/s. For shocks in the ~75 - 100 km/s range, where destruction is not complete, the PAH structure is likely to be severely denatured by the loss of an important fraction (20-40%) of the carbon atoms. We derive typical PAH lifetimes of the order of a few x10^8 yr for the Galaxy. These results are robust and independent of the uncertainties in some key parameters that have yet to be well-determined experimentally. Conclusions: The observation of PAH emission in shock regions implies that that emission either arises outside the shocked region or that those regions entrain denser clumps that, unless they are completely ablated and eroded in the shocked gas, allow dust and PAHs to survive in extreme environments.Comment: 19 pages, 11 figures, 3 tables, typos corrected and PAH acronym in the title substituted with full name to match version published in Astronomy and Astrophysic

Vision and perception of community on the use of recycled water for household laundry: A case study in Australia

This study investigates the community perception of household laundry as a new end use of recycled water in three different locations of Australia through a face to face questionnaire survey (n=478). The study areas were selected based on three categories of (1) non-user, (2) perspective user and (3) current user of recycled water. The survey results indicate that significantly higher number (70%) of the respondents supported the use of recycled water for washing machines (χ2=527.40, df=3; p=0.000). Significant positive correlation between the overall support for the new end use and the willingness of the respondents to use recycled water for washing machine was observed among all users groups (r=0.43, p=0.000). However, they had major concerns regarding the effects of recycled water on the aesthetic appearance of cloth, cloth durability, machine durability, odour of the recycled water and cost along with the health issues. The perspective user group had comparatively more reservations and concerns about the effects of recycled water on washing machines than the non-users and the current users (χ2=52.73, df=6; p=0.000). Overall, community from all three study areas are willing to welcome this new end use as long as all their major concerns are addressed and safety is assured. © 2013 Elsevier B.V

Factors influencing Hen Harrier Circus cyaneus territory site selection and breeding success

Capsule: Our findings regarding Hen Harrier Circus cyaneus territory site selection and breeding success in Ireland offer an opportunity for the development of initiatives and conservation actions aimed at enhancing the suitability of upland areas for breeding Hen Harriers and ensuring the long-term persistence of the species.Aims: To investigate landscape-scale associations between habitat composition and Hen Harrier territory site selection, and to explore the influence of habitat and climate on breeding success.Methods: We used multi-model inference from generalized linear models and Euclidean distance analyses to explore the influence of habitat, topographic, anthropogenic and climatic factors on Hen Harrier territory selection and breeding success in Ireland, based on data from national breeding surveys in 2010 and 2015.Results: Hen Harrier territories were associated with heath/shrub, bog and pre-thicket coniferous forests. Comparisons between territories and randomly generated pseudo-absences (upland and lowland) showed that breeding pairs preferentially select for these habitats. Breeding success was negatively influenced by rainfall early in the breeding season and by climatic instability, and was positively influenced by the presence of heath/shrub and bog.Conclusions: The results suggest that Hen Harrier breeding success is compromised by the synergistic effects of climate, landscape composition and management. Effective conservation of Hen Harriers in Ireland will therefore rely on landscape-scale initiatives