Pharmacological and functional regulation of two-pore domain potassium channels

Two pore domain potassium (K2P) channels underlie the background potassium leak currents of excitable cells. In this study, the whole cell patch clamp technique was used with transiently transfected human embryonic kidney cells, and cerebellar granule neurones (CGNs) in primary culture, to compare the pharmacological properties of acid sensitive K2P channels. Zn2+, La3+, Cu2+, ruthenium red and Ru-360 blocked TASK-1 and TASK-3 channel currents. Substitution of external sodium ions with N-methyl-D-glucamine and choline also caused a significant reduction in TASK-1 and TASK-3 currents, demonstrating that maximal conductance through these potassium channels requires the presence of external sodium ions. Whilst Cu2+ blocked TASK-1 and TASK-3 channel currents, TASK-2 currents were not affected by the ion. Mannitol, a scavenger of hydroxyl radicals, did not alter Cu2+ block of TASK-3 currents showing hydroxyl radical production was not the underlying mechanism. Application of thiol oxidant, DTNB (5’,5’-dithio-bis(2 nitrobenzoic acid)), showed a potent block, mimicking that of Cu2+ in size and reversibility. DTNB and Cu2+ block were reversed by disulphide-reducing DTT (dithiothreitol), suggesting thiol rich cysteine residues played a fundamental role in <y, TASK-3 current block by Cu . The standing-outward, voltage-insensitive potassium current in CGNs also showed DTNB and copper sensitivity. Substitutions of TASK-3 cysteine residues to alanine and serine retained copper sensitivity while whole cell current amplitude diminished and a sensitivity to alkaline pH (8.4) was introduced to TASK-3. Point mutation of cysteine 110 was found to be key in facilitating the pH 8.4 potentiation of current. Cu2+ and DTNB were applied to a TASK-2/TASK-3 chimera channel where a robust, albeit reduced, block was observed. The central role of the TASK channels in neuronal excitability is demonstrated by their extensive physiological and cross-species distribution and varied mechanisms of regulation. In this study, the interaction of essential trace element Cu2+ was shown to be a significant mechanism of TASK regulation.Open acces

The importance of fishing grounds as perceived by local communities can be undervalued by measures of socioeconomic cost used in conservation planning

Marine reserve placement must account for the importance of places for resource use to minimize negative socioeconomic impacts and improve compliance. It is often assumed that placing marine reserves in locations that minimize lost fishing opportunities will reduce impacts on coastal communities, but the influence of the fishing data used on this outcome remains poorly understood. In the Madang Lagoon (Papua New Guinea), we compared three types of proxies for conservation costs to local fishing communities. We developed two types of proxies of opportunity costs commonly used in marine conservation planning: current fishing activity with fisher surveys (n = 68) and proximity from shore. We also developed proxies based on areas of importance for fishing as perceived by surveyed households (n = 52). Although all proxies led to different configurations of potential marine reserves, the three types of cost data reflect different aspects of importance for fishing and should be used as complementary measures

Assessing the Early Holocene Environment of Northwestern Guyana: An Isotopic Analysis of Human and Faunal Remains

This study used stable carbon δ13C and oxygen δ18O isotope compositions data to assess the extent to which diet breadths of northwestern Guyana changed during the Holocene. We analyzed human bone and enamel remains from seven shell mound sites dating between 7500 and 2600 BP. Our analyses demonstrate some degree of constancy in the availability of C3 plants during the past several thousand years—though we note an increasing reliance on such plants beginning in the Early Holocene. We also document warming intervals during the Early Holocene (Early Archaic), which appear to correlate with dry periods known elsewhere in the central Amazon during this period

The Provision Of Data From The COSMOS-UK Soil Moisture Monitoring Network

This paper describes the data available from COSMOS-UK, a new soil moisture monitoring network for the UK based on passive cosmic-ray moisture probes which are capable of measuring average soil water content over a circular footprint of around 350m in radius and depths of up to 0.5 m. Around 35 probes, with an associated array of meteorological and point soil moisture sensors, will be deployed across the UK in a network designed to best represent a range of soil and land cover types, complement existing scientific monitoring over a wide range of subject areas, and capture the variability in soil moisture over the country. Data will be automatically quality controlled and data streams will be openly and freely accessible via services and formats that conform to existing international standards, enabling integration with forecasting and data assimilation systems

Structural and psycho-social limits to climate change adaptation in the great barrier reef region

Adaptation, as a strategy to respond to climate change, has limits: there are conditions under which adaptation strategies fail to alleviate impacts from climate change. Research has primarily focused on identifying absolute bio-physical limits. This paper contributes empirical insight to an emerging literature on the social limits to adaptation. Such limits arise from the ways in which societies perceive, experience and respond to climate change. Using qualitative data from multi-stakeholder workshops and key-informant interviews with representatives of the fisheries and tourism sectors of the Great Barrier Reef region, we identify psycho-social and structural limits associated with key adaptation strategies, and examine how these are perceived as more or less absolute across levels of organisation. We find that actors experience social limits to adaptation when: i) the effort of pursuing a strategy exceeds the benefits of desired adaptation outcomes; ii) the particular strategy does not address the actual source of vulnerability, and; iii) the benefits derived from adaptation are undermined by external factors. We also find that social limits are not necessarily more absolute at higher levels of organisation: respondents perceived considerable opportunities to address some psycho-social limits at the national-international interface, while they considered some social limits at the local and regional levels to be effectively absolute

Assessing Trade-Offs in Large Marine Protected Areas

Large marine protected areas (LMPAs) are increasingly being established and have a high profile in marine conservation. LMPAs are expected to achieve multiple objectives, and because of their size are postulated to avoid trade-offs that are common in smaller MPAs. However, evaluations across multiple outcomes are lacking. We used a systematic approach to code several social and ecological outcomes of 12 LMPAs. We found evidence of three types of trade-offs: trade-offs between different ecological resources (supply trade-offs); trade-offs between ecological resource conditions and the well-being of resource users (supply-demand trade-offs); and trade-offs between the well-being outcomes of different resource users (demand trade-offs). We also found several divergent outcomes that were attributed to influences beyond the scope of the LMPA. We suggest that despite their size, trade-offs can develop in LMPAs and should be considered in planning and design. LMPAs may improve their performance across multiple social and ecological objectives if integrated with larger-scale conservation efforts. © 2018 Davies et al

Principle 4 – foster complex adaptive systems thinking

The social–ecological systems that provide ecosystem services to society can be viewed as complex adaptive systems (CAS), characterized by a high level of interconnectedness, potential for non-linear change, and inherent uncertainty and surprise. This chapter focuses on whether resilience of ecosystem services is enhanced by management based on what we refer to as ‘CAS thinking’, meaning a mental model for interpreting the world that recognizes these CAS properties. We present evidence that CAS thinking has contributed to change in management approaches in the Kruger National Park, Great Barrier Reef, Tisza river basin and Chile among other places. However, attempts to introduce CAS thinking may compromise resilience when complexity is not effectively communicated, when uncomfortable institutional change is required or when CAS thinking is not able to evolve with changing contexts or is not equitably shared. We suggest that CAS thinking can be fostered by the following: adopting a systems framework; tolerating and embracing uncertainty; investigating critical thresholds and non-linearities; acknowledging epistemological pluralism; matching institutions to CAS processes; and recognizing barriers to cognitive change. Key questions for future research on this principle relate to communicating CAS thinking, the role of power, the importance of an organizational level of CAS thinking, and institutional barriers

Future Scenarios as a Research Tool: Investigating Climate Change Impacts, Adaptation Options and Outcomes for the Great

Abstract Climate change is a significant future driver of change in coastal social-ecological systems. Our knowledge of impacts, adaptation options, and possible outcomes for marine environments and coastal industries is expanding, but remains limited and uncertain. Alternative scenarios are a way to explore potential futures under a range of conditions. We developed four alternative future scenarios for the Great Barrier Reef and its fishing and tourism industries positing moderate and more extreme (2-3°C above pre-industrial temperatures) warming for 2050 and contrasting &apos;limited&apos; and &apos;ideal&apos; ecological and social adaptation. We presented these scenarios to representatives of key stakeholder groups to assess the perceived viability of different social adaptation options to deliver desirable outcomes under varied contexts

Exploring ‘islandness’ and the impacts of nature conservation through the lens of wellbeing

Motivated by growing concern as to the many threats that islands face, subsequent calls for more extensive island nature conservation and recent discussion in the conservation literature about the potential for wellbeing as a useful approach to understanding how conservation affects people's lives, this paper reviews the literature in order to explore how islands and wellbeing relate and how conservation might impact that relationship. We apply a three-dimensional concept of social wellbeing to structure the discussion and illustrate the importance of understanding island–wellbeing interactions in the context of material, relational and subjective dimensions, using examples from the literature. We posit that islands and their shared characteristics of ‘islandness’ provide a useful setting in which to apply social wellbeing as a generalizable framework, which is particularly adept at illuminating the relevance of social relationships and subjective perceptions in island life – aspects that are often marginalized in more economically focused conservation impact assessments. The paper then explores in more depth the influences of island nature conservation on social wellbeing and sustainability outcomes using two case studies from the global north (UK islands) and global south (the Solomon Islands). We conclude that conservation approaches that engage with all three dimensions of wellbeing seem to be associated with success

Arterial oxygen content is precisely maintained by graded erythrocytotic responses in settings of high/normal serum iron levels, and predicts exercise capacity: an observational study of hypoxaemic patients with pulmonary arteriovenous malformations.

Oxygen, haemoglobin and cardiac output are integrated components of oxygen transport: each gram of haemoglobin transports 1.34 mls of oxygen in the blood. Low arterial partial pressure of oxygen (PaO2), and haemoglobin saturation (SaO2), are the indices used in clinical assessments, and usually result from low inspired oxygen concentrations, or alveolar/airways disease. Our objective was to examine low blood oxygen/haemoglobin relationships in chronically compensated states without concurrent hypoxic pulmonary vasoreactivity.165 consecutive unselected patients with pulmonary arteriovenous malformations were studied, in 98 cases, pre/post embolisation treatment. 159 (96%) had hereditary haemorrhagic telangiectasia. Arterial oxygen content was calculated by SaO2 x haemoglobin x 1.34/100.There was wide variation in SaO2 on air (78.5-99, median 95)% but due to secondary erythrocytosis and resultant polycythaemia, SaO2 explained only 0.1% of the variance in arterial oxygen content per unit blood volume. Secondary erythrocytosis was achievable with low iron stores, but only if serum iron was high-normal: Low serum iron levels were associated with reduced haemoglobin per erythrocyte, and overall arterial oxygen content was lower in iron deficient patients (median 16.0 [IQR 14.9, 17.4]mls/dL compared to 18.8 [IQR 17.4, 20.1]mls/dL, p<0.0001). Exercise tolerance appeared unrelated to SaO2 but was significantly worse in patients with lower oxygen content (p<0.0001). A pre-defined athletic group had higher Hb:SaO2 and serum iron:ferritin ratios than non-athletes with normal exercise capacity. PAVM embolisation increased SaO2, but arterial oxygen content was precisely restored by a subsequent fall in haemoglobin: 86 (87.8%) patients reported no change in exercise tolerance at post-embolisation follow-up.Haemoglobin and oxygen measurements in isolation do not indicate the more physiologically relevant oxygen content per unit blood volume. This can be maintained for SaO2 ≥78.5%, and resets to the same arterial oxygen content after correction of hypoxaemia. Serum iron concentrations, not ferritin, seem to predict more successful polycythaemic responses