Evidence of an interaction between the actin cytoskeletal regulators MIG-10 and ABI-1

Cell and process migration are critical to the establishment of neural circuitry. The study of these processes is facilitated through use of model organisms with simple nervous systems, such as C. elegans. Research in this nematode has defined the cytoplasmic adaptor MIG-10 as a key regulator of these processes. Mutation of mig-10 disrupts neuronal and axonal migration and outgrowth of the ‘canals’, or processes, of the excretory cell. MIG-10 directs the localization of UNC-34, which remodels actin filaments at the leading edge of a migrating cell or process to modify the direction or rate of its protrusion. An interactor of MIG-10 identified in a yeast two- hybrid analysis, ABI-1, has several roles in actin remodeling, such as targeting Ena/VASP members for phosphorylation by Abl kinase. Mutation of abi-1 in the nematode produces phenotypes that resemble those of mig-10 mutants, including disrupted outgrowth of the excretory canals, a developmental process in which ABI-1 is known to function cell autonomously. To test the hypothesis that the ABI-1/MIG-10 interaction contributes to cell migration and outgrowth, both in vivo and in vitro analyses were performed. Expression of either MIG-10A or MIG-10B exclusively in the excretory cell partially rescued the canal truncation characteristic of mig-10 mutants, suggesting MIG-10 functions autonomously in this cell during canal outgrowth. Physical interaction between MIG-10 and ABI-1 was confirmed using a co-immunoprecipitation system. Both MIG-10A and MIG-10B interact with ABI-1 through a mechanism that likely involves the SH3 domain of ABI-1 and sites in either the central region or C-terminus of MIG-10. These results suggest that MIG-10 and ABI-1 function together in a cell autonomous manner to promote cell or process migration. A possible consequence of this interaction is modulation of the MIG-10 binding to UNC-34 through Abl-mediated phosphorylation of MIG-10

An alternative approach for detecting hearing loss in adults with learning disabilities.

1.1 Background Annual health checks in primary care include hearing assessment, though current guidance recommends subjective assessment only. Previous studies suggest this is inadequate and recommend objective alternatives such as hearing screening. This study aimed to assess the feasibility of hearing screening and examine the last recorded annual health check outcome for hearing, for those diagnosed with hearing loss as a result of the screening process. 1.2 Method Hearing screening took place in four locations and 75 people with learning disabilities participated. Contact was made with each individual's GP to share results and to request onward referral where indicated. 1.3 Findings Wax occlusion prevented screening for 23%. Fifty‐seven people completed the screen, and 25 had suspected hearing loss. Of these, 22 people required referral to Audiology to verify their hearing thresholds. Only 13 were actually referred, and 11 individuals underwent assessment in Audiology, resulting in 10 being diagnosed with hearing loss. The most recent annual health check outcomes for hearing were examined for those diagnosed with hearing loss. Of the records we accessed, hearing loss had not been identified or actioned in every case. 1.4 Conclusions Hearing screening is shown here to be a suitable method for detecting hearing loss. We recommend changing current annual health check practice to incorporate objective screening. Only 12% of those with suspected hearing loss were known to Audiology services, suggesting a substantial proportion of undetected hearing loss in the community. We found evidence of apparent reluctance around referral and hearing aid fitting and make suggestions for improvement

Neuronal cell cycle re-entry mediates Alzheimer disease-type changes

AbstractEvidence showing the ectopic re-expression of cell cycle-related proteins in specific vulnerable neuronal populations in Alzheimer disease led us to formulate the hypothesis that neurodegeneration, like cancer, is a disease of inappropriate cell cycle control. To test this notion, we used adenoviral-mediated expression of c-myc and ras oncogenes to drive postmitotic primary cortical neurons into the cell cycle. Cell cycle re-entry in neurons was associated with increased DNA content, as determined using BrdU and DAPI, and the re-expression of cyclin B1, a marker for the G2/M phase of the cell cycle. Importantly, we also found that cell cycle re-entry in primary neurons leads to tau phosphorylation and conformational changes similar to that seen in Alzheimer disease. This study establishes that the cell cycle can be instigated in normally quiescent neuronal cells and results in a phenotype that shares features of degenerative neurons in Alzheimer disease. As such, our neuronal cell model may be extremely valuable for the development of novel therapeutic strategies

A Functional Naturalism

I provide two arguments against value-free naturalism. Both are based on considerations concerning biological teleology. Value-free naturalism is the thesis that both (1) everything is, at least in principle, under the purview of the sciences and (2) all scientific facts are purely non-evaluative. First, I advance a counterexample to any analysis on which natural selection is necessary to biological teleology. This should concern the value-free naturalist, since most value-free analyses of biological teleology appeal to natural selection. My counterexample is unique in that it is likely to actually occur. It concerns the creation of synthetic life. Recent developments in synthetic biology suggest scientists will eventually be able to develop synthetic life. Such life, however, would not have any of its traits naturally selected for. Second, I develop a simple argument that biological teleology is a scientific but value-laden notion. Consequently, value-free naturalism is false. I end with some concluding remarks on the implications for naturalism, the thesis that (1). Naturalism may be salvaged only if we reject (2). (2) is a dogma that unnecessarily constrains our conception of the sciences. Only a naturalism that recognizes value-laden notions as scientifically respectable can be true. Such a naturalism is a functional naturalism

The Geozoic Supereon

Geological time units are the lingua franca of earth sciences: they are a terminological convenience, a vernacular of any geological conversation, and a prerequisite of geo-scientific writing found throughout in earth science dictionaries and textbooks. Time units include terms formalized by stratigraphic committees as well as informal constructs erected ad hoc to communicate more efficiently. With these time terms we partition Earth’s history into utilitarian and intuitively understandable time segments that vary in length over seven orders of magnitude: from the 225-year-long Anthropocene (Crutzen and Stoermer, 2000) to the ,4-billion-year-long Precambrian (e.g., Hicks, 1885; Ball, 1906; formalized by De Villiers, 1969)

Comparing the hierarchy of keywords in on-line news portals

The tagging of on-line content with informative keywords is a widespread phenomenon from scientific article repositories through blogs to on-line news portals. In most of the cases, the tags on a given item are free words chosen by the authors independently. Therefore, relations among keywords in a collection of news items is unknown. However, in most cases the topics and concepts described by these keywords are forming a latent hierarchy, with the more general topics and categories at the top, and more specialised ones at the bottom. Here we apply a recent, cooccurrence-based tag hierarchy extraction method to sets of keywords obtained from four different on-line news portals. The resulting hierarchies show substantial differences not just in the topics rendered as important (being at the top of the hierarchy) or of less interest (categorised low in the hierarchy), but also in the underlying network structure. This reveals discrepancies between the plausible keyword association frameworks in the studied news portals

Degeneracy: a link between evolvability, robustness and complexity in biological systems

A full accounting of biological robustness remains elusive; both in terms of the mechanisms by which robustness is achieved and the forces that have caused robustness to grow over evolutionary time. Although its importance to topics such as ecosystem services and resilience is well recognized, the broader relationship between robustness and evolution is only starting to be fully appreciated. A renewed interest in this relationship has been prompted by evidence that mutational robustness can play a positive role in the discovery of adaptive innovations (evolvability) and evidence of an intimate relationship between robustness and complexity in biology. This paper offers a new perspective on the mechanics of evolution and the origins of complexity, robustness, and evolvability. Here we explore the hypothesis that degeneracy, a partial overlap in the functioning of multi-functional components, plays a central role in the evolution and robustness of complex forms. In support of this hypothesis, we present evidence that degeneracy is a fundamental source of robustness, it is intimately tied to multi-scaled complexity, and it establishes conditions that are necessary for system evolvability

How large should whales be?

The evolution and distribution of species body sizes for terrestrial mammals is well-explained by a macroevolutionary tradeoff between short-term selective advantages and long-term extinction risks from increased species body size, unfolding above the 2g minimum size induced by thermoregulation in air. Here, we consider whether this same tradeoff, formalized as a constrained convection-reaction-diffusion system, can also explain the sizes of fully aquatic mammals, which have not previously been considered. By replacing the terrestrial minimum with a pelagic one, at roughly 7000g, the terrestrial mammal tradeoff model accurately predicts, with no tunable parameters, the observed body masses of all extant cetacean species, including the 175,000,000g Blue Whale. This strong agreement between theory and data suggests that a universal macroevolutionary tradeoff governs body size evolution for all mammals, regardless of their habitat. The dramatic sizes of cetaceans can thus be attributed mainly to the increased convective heat loss is water, which shifts the species size distribution upward and pushes its right tail into ranges inaccessible to terrestrial mammals. Under this macroevolutionary tradeoff, the largest expected species occurs where the rate at which smaller-bodied species move up into large-bodied niches approximately equals the rate at which extinction removes them.Comment: 7 pages, 3 figures, 2 data table

The Minimal Complexity of Adapting Agents Increases with Fitness

What is the relationship between the complexity and the fitness of evolved organisms, whether natural or artificial? It has been asserted, primarily based on empirical data, that the complexity of plants and animals increases as their fitness within a particular environment increases via evolution by natural selection. We simulate the evolution of the brains of simple organisms living in a planar maze that they have to traverse as rapidly as possible. Their connectome evolves over 10,000s of generations. We evaluate their circuit complexity, using four information-theoretical measures, including one that emphasizes the extent to which any network is an irreducible entity. We find that their minimal complexity increases with their fitness