CETP Expression Protects Female Mice from Obesity-Induced Decline in Exercise Capacity

Pharmacological approaches to reduce obesity have not resulted in dramatic reductions in the risk of coronary heart disease (CHD). Exercise, in contrast, reduces CHD risk even in the setting of obesity. Cholesteryl Ester Transfer Protein (CETP) is a lipid transfer protein that shuttles lipids between serum lipoproteins and tissues. There are sexual-dimorphisms in the effects of CETP in humans. Mice naturally lack CETP, but we previously reported that transgenic expression of CETP increases muscle glycolysis in fasting and protects against insulin resistance with high-fat diet (HFD) feeding in female but not male mice. Since glycolysis provides an important energy source for working muscle, we aimed to define if CETP expression protects against the decline in exercise capacity associated with obesity. We measured exercise capacity in female mice that were fed a chow diet and then switched to a HFD. There was no difference in exercise capacity between lean, chow-fed CETP female mice and their non-transgenic littermates. Female CETP transgenic mice were relatively protected against the decline in exercise capacity caused by obesity compared to WT. Despite gaining similar fat mass after 6 weeks of HFD-feeding, female CETP mice showed a nearly two-fold increase in run distance compared to WT. After an additional 6 weeks of HFD-feeding, mice were subjected to a final exercise bout and muscle mitochondria were isolated. We found that improved exercise capacity in CETP mice corresponded with increased muscle mitochondrial oxidative capacity, and increased expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). These results suggest that CETP can protect against the obesity-induced impairment in exercise capacity and may be a target to improve exercise capacity in the context of obesity.     

Practitioner versus participant perspectives on conservation tenders

Extensive clearing of native vegetation on rural properties throughout Australia over the last century has generated significant damage to biodiversity. Conservation tenders have been broadly used to reduce the detrimental impact of such widespread clearance. To date, Australian conservation tender research has largely been limited to program evaluations and landholder surveys. This analysis differs by comparing and contrasting the views of non-landholders involved with these programs with those of participant landholders. The non-landholder group consists of individuals with involvement in conservation tenders across Australia. By contrast, the landholder group consists of individuals with participation experience in a series of Victorian tender initiatives. Each group is surveyed to investigate the drivers of cost-effectiveness within tender programs and landholder participation. This analysis explores these two perspectives, revealing important convergences and divergences in opinion. Both practitioners and landholders indicate that programs supported by close agency–landholder relationships and offering flexibility to landholders are most likely to succeed, particularly where landholders perceive the tender instrument to be fair. Whilst practitioners emphasise the role of transaction costs issues and program characteristics in achieving cost-effective biodiversity outcomes, landholders indicate that these factors are less important to participation rates. This research is important to guide future implementation of tender programs both in Australia and internationally.     

Root growth dynamics linked to above-ground growth in walnut (Juglans regia)

Background and Aims Examination of plant growth below ground is relatively scant compared with that above ground, and is needed to understand whole-plant responses to the environment. This study examines whether the seasonal timing of fine root growth and the spatial distribution of this growth through the soil profile varies in response to canopy manipulation and soil temperature.Methods Plasticity in the seasonal timing and vertical distribution of root production in response to canopy and soil water manipulation was analysed in field-grown walnut (Juglans regia ‘Chandler’) using minirhizotron techniques.Key Results Root production in walnuts followed a unimodal curve, with one marked flush of root growth starting in mid-May, with a peak in mid-June. Root production declined later in the season, corresponding to increased soil temperature, as well as to the period of major carbohydrate allocation to reproduction. Canopy and soil moisture manipulation did not influence the timing of root production, but did influence the vertical distribution of roots through the soil profile. Water deficit appeared to promote root production in deeper soil layers for mining soil water. Canopy removal appeared to promote shallow root production.Conclusions The findings of this study add to growing evidence that root growth in many ecosystems follows a unimodal curve with one marked flush of root growth in coordination with the initial leaf flush of the season. Root vertical distribution appeared to have greater plasticity than timing of root production in this system, with temperature and/or carbohydrate competition constraining the timing of root growth. Effects on root distribution can have serious impacts on trees, with shallow rooting having negative impacts in years with limited soil water or positive impacts in years with wet springs, and deep rooting having positive impacts on soil water mining from deeper soil layers but negative impacts in years with wet springs.     

Structuring policy problems for plastics,the environment and human health: reflections from the UK

How can we strengthen the science–policy interface for plastics, the environment and human health? In a complex policy area with multiple stakeholders, it is important to clarify the nature of the particular plastics-related issue before trying to understand how to reconcile the supply and demand for evidence in policy. This article proposes a simple problem typology to assess the fundamental characteristics of a policy issue and thus identify appropriate processes for science–policy interactions. This is illustrated with two case studies from one UK Government Department, showing how policy and science meet over the environmental problems of plastics waste in the marine environment and on land. A problem-structuring methodology helps us understand why some policy issues can be addressed through relatively linear flows of science from experts to policymakers but why others demand a more reflexive approach to brokering the knowledge between science and policy. Suggestions are given at the end of the article for practical actions that can be taken on both sides.     

Interactions Among Fuel Management,Species Composition,Bark Beetles,and Climate Change and the Potential Effects on Forests of the Lake Tahoe Basin

Climate-driven increases in wildfires, drought conditions, and insect outbreaks are critical threats to forest carbon stores. In particular, bark beetles are important disturbance agents although their long-term interactions with future climate change are poorly understood. Droughts and the associated moisture deficit contribute to the onset of bark beetle outbreaks although outbreak extent and severity is dependent upon the density of host trees, wildfire, and forest management. Our objective was to estimate the effects of climate change and bark beetle outbreaks on ecosystem carbon dynamics over the next century in a western US forest. Specifically, we hypothesized that (a) bark beetle outbreaks under climate change would reduce net ecosystem carbon balance (NECB) and increase uncertainty and (b) these effects could be ameliorated by fuels management. We also examined the specific tree species dynamics—competition and release—that determined NECB response to bark beetle outbreaks. Our study area was the Lake Tahoe Basin (LTB), CA and NV, USA, an area of diverse forest types encompassing steep elevation and climatic gradients and representative of mixed-conifer forests throughout the western United States. We simulated climate change, bark beetles, wildfire, and fuels management using a landscape-scale stochastic model of disturbance and succession. We simulated the period 2010–2100 using downscaled climate projections. Recurring droughts generated conditions conducive to large-scale outbreaks; the resulting large and sustained outbreaks significantly increased the probability of LTB forests becoming C sources over decadal time scales, with slower-than-anticipated landscape-scale recovery. Tree species composition was substantially altered with a reduction in functional redundancy and productivity. Results indicate heightened uncertainty due to the synergistic influences of climate change and interacting disturbances. Our results further indicate that current fuel management practices will not be effective at reducing landscape-scale outbreak mortality. Our results provide critical insights into the interaction of drivers (bark beetles, wildfire, fuel management) that increase the risk of C loss and shifting community composition if bark beetle outbreaks become more frequent.     

To share or not to share: Incentivizing data sharing in life science communities

Most scientists recognize the importance of sharing data online in an open fashion. Nonetheless, many studies have documented the concerns that accompany data sharing activities, including loss of credit or IP, misuse and the time needed to curate interoperable data. To this end, discussions around data sharing often identify incentives that could potentially ameliorate these disincentivising concerns. Nonetheless, current Open Data discussions often rely on evidence‐based studies to identify the disincentives to overcome. This results in highly specific and directed interventions. In contrast, this paper offers a different interpretation of these concerns. To do so, it makes use of the Thomas Theorem which suggests that: “If men define situations as real, they are real in their consequences”. Using empirical evidence from sub‐Saharan African (bio)chemistry laboratories, this paper illustrates how individual perceptions of research environments – whether associated with evidence or not – are highly influential in shaping data sharing practices. It concludes with the suggestion that discussion on incentivising data sharing amongst scientific communities need to take a broader set of concerns into account and offer a more creative approach to ameliorating environmental disincentives.     

Can Schools Support HIV/AIDS-Affected Children? Exploring the ‘Ethic of Care’ amongst Rural Zimbabwean Teachers

How realistic is the international policy emphasis on schools ‘substituting for families’ of HIV/AIDS-affected children? We explore the ethic of care in Zimbabwean schools to highlight the poor fit between the western caring schools literature and daily realities of schools in different material and cultural contexts. Interviews and focus groups were conducted with 44 teachers and 55 community members, analysed in light of a companion study of HIV/AIDS-affected pupils’ own accounts of their care-related experiences. We conceptualise schools as spaces of engagement between groups with diverse needs and interests (teachers, pupils and surrounding community members), with attention to the pathways through which extreme adversity impacts on those institutional contexts and social identifications central to giving and receiving care. Whilst teachers were aware of how they might support children, they seldom put these ideas into action. Multiple factors undermined caring teacher-pupil relationships in wider contexts of poverty and political uncertainty: loss of morale from low salaries and falling professional status; the inability of teachers to solve HIV/AIDS-related problems in their own lives; the role of stigma in deterring HIV/AIDS-affected children from disclosing their situations to teachers; authoritarian teacher-learner relations and harsh punishments fuelling pupil fear of teachers; and lack of trust in the wider community. These factors undermined: teacher confidence in their skills and capacity to support affected pupils and motivation to help children with complex problems; solidarity and common purpose amongst teachers, and between teachers and affected children; and effective bridging alliances between schools and their surrounding communities–all hallmarks of HIV-competent communities. We caution against ambitious policy expansions of teachers'' roles without recognition of the personal and social costs of emotional labour, and the need for significant increases in resources and institutional recognition to enable teachers to adopt support roles. We highlight the need for research into how best to create opportunities for teacher recognition in deprived and disorganised institutional settings, and the development of more culturally appropriate notions of caring.