An individual-based profitability spectrum for understanding interactions between predators and their prey

There is confusion in the animal behaviour literature over the use of the terms ‘toxicity’ and ‘unpalatability’, which are commonly used interchangeably when describing the function of chemical compounds in prey, although these terms describe very different functions. Toxic chemicals cause fitness-reducing harm, whereas unpalatability provides aversive taste but no reduction in fitness. Furthermore, chemical defences are only one aspect of prey profitability. We argue that if predators are maximizing fitness, all prey can be described in terms of their costs and benefits to predators across all currencies, giving each prey item a positive or negative position on a ‘profitability spectrum’. Adaptively foraging predators should be selected to eat only prey with a positive profitability. The context of each predator–prey encounter also alters the profitability of the prey. Given that profitability is a function of the current state of both the predator and the prey individuals, we explain why it should be considered to be an attribute of a particular encounter, in contrast to its present usage as an attribute of a prey species. This individual-centred perspective requires researchers to investigate, through both theoretical models and empirical studies, the complex conditions in which predators and prey meet in real life

A large-scale experiment finds no evidence that a seismic survey impacts a demersal fish fauna

Seismic surveys are used to locate oil and gas reserves below the seabed and can be a major source of noise in marine environments. Their effects on commercial fisheries are a subject of debate, with experimental studies often producing results that are difficult to interpret. We overcame these issues in a large-scale experiment that quantified the impacts of exposure to a commercial seismic source on an assemblage of tropical demersal fishes targeted by commercial fisheries on the North West Shelf of Western Australia. We show that there were no short-term (days) or long-term (months) effects of exposure on the composition, abundance, size structure, behavior, or movement of this fauna. These multiple lines of evidence suggest that seismic surveys have little impact on demersal fishes in this environment

Integrative analysis of RUNX1 downstream pathways and target genes

Background: The RUNX1 transcription factor gene is frequently mutated in sporadic myeloid and lymphoid leukemia through translocation, point mutation or amplification. It is also responsible for a familial platelet disorder with predisposition to acute myeloid leukemia (FPD-AML). The disruption of the largely unknown biological pathways controlled by RUNX1 is likely to be responsible for the development of leukemia. We have used multiple microarray platforms and bioinformatic techniques to help identify these biological pathways to aid in the understanding of why RUNX1 mutations lead to leukemia. Results: Here we report genes regulated either directly or indirectly by RUNX1 based on the study of gene expression profiles generated from 3 different human and mouse platforms. The platforms used were global gene expression profiling of: 1) cell lines with RUNX1 mutations from FPD-AML patients, 2) over-expression of RUNX1 and CBF[Beta], and 3) Runx1 knockout mouse embryos using either cDNA or Affymetrix microarrays. We observe that our datasets (lists of differentially expressed genes) significantly correlate with published microarray data from sporadic AML patients with mutations in either RUNX1 or its cofactor, CBF[Beta]. A number of biological processes were identified among the differentially expressed genes and functional assays suggest that heterozygous RUNX1 point mutations in patients with FPD-AML impair cell proliferation, microtubule dynamics and possibly genetic stability. In addition, analysis of the regulatory regions of the differentially expressed genes has for the first time systematically identified numerous potential novel RUNX1 target genes. Conclusion: This work is the first large-scale study attempting to identify the genetic networks regulated by RUNX1, a master regulator in the development of the hematopoietic system and leukemia. The biological pathways and target genes controlled by RUNX1 will have considerable importance in disease progression in both familial and sporadic leukemia as well as therapeutic implications

Wideband Instrument for Snow Measurements (WISM)

This presentation discusses current efforts to develop a Wideband Instrument for Snow Measurements (WISM). The objective of the effort are as follows: to advance the utility of a wideband active and passive instrument (8-40 gigahertz) to support the snow science community; improve snow measurements through advanced calibration and expanded frequency of active and passive sensors; demonstrate science utility through airborne retrievals of snow water equivalent (SWE); and advance the technology readiness of broadband current sheet array (CSA) antenna technology for spaceflight applications

Herbal supplements in the print media: communicating benefits and risks

Background The rise in use of food supplements based on botanical ingredients (herbal supplements) is depicted as part of a trend empowering consumers to manage their day-to-day health needs, which presupposes access to clear and accurate information to make effective choices. Evidence regarding herbal supplement efficacy is extremely variable so recent regulations eliminating unsubstantiated claims about potential effects leave producers able to provide very little information about their products. Medical practitioners are rarely educated about herbal supplements and most users learn about them via word-of-mouth, allowing dangerous misconceptions to thrive, chief among them the assumption that natural products are inherently safe. Print media is prolific among the information channels still able to freely discuss herbal supplements. Method This study thematically analyses how 76 newspaper/magazine articles from the UK, Romania and Italy portray the potential risks and benefits of herbal supplements. Results Most articles referenced both risks and benefits and were factually accurate but often lacked context and impartiality. More telling was how the risks and benefits were framed in service of a chosen narrative, the paucity of authoritative information allowing journalists leeway to recontextualise herbal supplements in ways that serviced the goals and values of their specific publications and readerships. Conclusion Providing sufficient information to empower consumers should not be the responsibility of print media, instead an accessible source of objective information is required.</p

Growth rings show limited evidence for ungulates' potential to suppress shrubs across the Arctic

Global warming has pronounced effects on tundra vegetation, and rising mean temperatures increase plant growth potential across the Arctic biome. Herbivores may counteract the warming impacts by reducing plant growth, but the strength of this effect may depend on prevailing regional climatic conditions. To study how ungulates interact with temperature to influence growth of tundra shrubs across the Arctic tundra biome, we assembled dendroecological data from 20 sites, comprising 1153 individual shrubs and 223 63 annual growth rings. Evidence for ungulates suppressing shrub radial growth was only observed at intermediate summer temperatures (6.5 degrees C-9 degrees C), and even at these temperatures the effect was not strong. Multiple factors, including forage preferences and landscape use by the ungulates, and favourable climatic conditions enabling effective compensatory growth of shrubs, may weaken the effects of ungulates on shrubs, possibly explaining the weakness of observed ungulate effects. Earlier local studies have shown that ungulates may counteract the impacts of warming on tundra shrub growth, but we demonstrate that ungulates' potential to suppress shrub radial growth is not always evident, and may be limited to certain climatic conditions

Deletion of the Pluripotency-Associated Tex19.1 Gene Causes Activation of Endogenous Retroviruses and Defective Spermatogenesis in Mice

As genetic information is transmitted through successive generations, it passes between pluripotent cells in the early embryo and germ cells in the developing foetus and adult animal. Tex19.1 encodes a protein of unknown function, whose expression is restricted to germ cells and pluripotent cells. During male spermatogenesis, Tex19.1 expression is highest in mitotic spermatogonia and diminishes as these cells differentiate and progress through meiosis. In pluripotent stem cells, Tex19.1 expression is also downregulated upon differentiation. However, it is not clear whether Tex19.1 has an essential function in germ cells or pluripotent stem cells, or what that function might be. To analyse the potential role of Tex19.1 in pluripotency or germ cell function we have generated Tex19.1−/− knockout mice and analysed the Tex19.1−/− mutant phenotype. Adult Tex19.1−/− knockout males exhibit impaired spermatogenesis. Immunostaining and histological analysis revealed defects in meiotic chromosome synapsis, the persistence of DNA double-strand breaks during meiosis, and a loss of post-meiotic germ cells in the testis. Furthermore, expression of a class of endogenous retroviruses is upregulated during meiosis in the Tex19.1−/− testes. Increased transposition of endogenous retroviruses in the germline of Tex19.1−/− mutant mice, and the concomitant increase in DNA damage, may be sufficient to disrupt the normal processes of recombination and chromosome synapsis during meiosis and cause defects in spermatogenesis. Our results suggest that Tex19.1 is part of a specialised mechanism that operates in the germline to repress transposable genetic elements and maintain genomic stability through successive generations

Location of studies and evidence of effects of herbivory on Arctic vegetation: a systematic map

Herbivores modify the structure and function of tundra ecosystems. Understanding their impacts is necessary to assess the responses of these ecosystems to ongoing environmental changes. However, the effects of herbivores on plants and ecosystem structure and function vary across the Arctic. Strong spatial variation in herbivore effects implies that the results of individual studies on herbivory depend on local conditions, i.e., their ecological context. An important first step in assessing whether generalizable conclusions can be produced is to identify the existing studies and assess how well they cover the underlying environmental conditions across the Arctic. This systematic map aims to identify the ecological contexts in which herbivore impacts on vegetation have been studied in the Arctic. Specifically, the primary question of the systematic map was: “What evidence exists on the effects of herbivores on Arctic vegetation?”