An investigation into the Murihiku toheroa (paphies ventricosa) : matauranga, monitoring and management

The value of traditional ecological knowledge and associated traditional practices, or matauranga and tikanga in the New Zealand Maori context, is playing an increasingly important role in the development of effective wildfoods management. Kaitiaki (environmental guardians) in Murihiku (Southland) are concerned about the successful transmission of the matauranga surrounding the ecology, management and threats of the toheroa (Paphies ventricosa). Populations of toheroa, a highly prized endemic surf clam, are found at Oreti, Orepuki and Bluecliffs beaches within Murihiku of which numbers are historically low. Bluecliffs Beach has experienced large sand erosion leaving on so% of the original habitat suitable for the toheroa. Twenty-five semi-directive interviews were conducted across a range ofkaitiaki, local experts and scientists. Interviewees identified the main threats, concerns and gaps in the research surrounding the toheroa and dictated the main aims within this present investigation. Discussions surrounding the traditional practice of translocating toheroa revealed the presence of the third colony at Orepuki Beach, Te Waewae Bay. A population a third the size of the 2005 Bluecliffs Beach population has established at Orepuki Beach from translocation efforts by local community members. The maintenance of this population is of great importance to the resilience of the Te Waewae Bay toheroa given the degraded state of the Bluecliffs Beach population. The potential use of translocation as a stock enhancement tool may have broad potential to secure and increase the resilience of the Murihiku toheroa meta-populations. Translocation of adult toheroa to enhance existing stocks density and to establish new populations is considered the most practical option. The destructive nature of the current population survey techniques and its lack of adhering to tikanga lead to the wish for a non-destructive abundance index based on traditional search methods to be developed. The observation and counting of siphon activity (siphon tips and holes in the sand) provided a poor predictor of absolute toheroa density when compared with densities generated from the excavation surveys. However observing siphon activity in relatively warm temperatures (16°C and above) provides a 95% certain rate of detection during one search. Thus siphon activity searching provides a sound means to assess the presence/absence and distribution of toheroa colonies. The main threats to toheroa were identified as beach traffic, mass mortalities, illegal harvesting, predations, pollution and climate change. All of which are poorly quantified. Preliminary investigations provided evidence of beach traffic adversely impacting juvenile (≤ 39 mm) toheroa, particularly those in the softer sand. Injury rates increased with vehicles with large, spaced lugs on the tyre tread and the motorbike test vehicle killed 18% of toheroa exposed to a single passage compared to an average of 3% for the car/utility vehicles. Similarly the Burt Munro Challenge beach race, an annual motorbike event held of Oreti Beach, caused a 72% (95% CI 40- 90%) juvenile mortality rate within a 1-2 km stretch of the beach. Further research into quantifying the risk of beach traffic, along with important biological parameters (i.e age/size and maximum reproductive potential) need to addressed. The results of this present investigation clearly illustrates of how TEK and its associated practices are relevant to the effective management of wildfood resources. Future development into the management of the Murihiku toheroa should encompass an active adaptive management approach

Modelling the effects of climate on long-term patterns of dissolved organic carbon concentrations in the surface waters of a boreal catchment

International audienceDissolved organic carbon concentrations ([DOC]) in surface waters are increasing in many regions of Europe and North America. These increases are likely driven by a combination of changing climate, recovery from acidification and change in severity of winter storms in coastal areas. INCA-C, a process-based model of climate effects on surface water [DOC], was used to explore the mechanisms by which changing climate controls seasonal to inter-annual patterns of [DOC] in the lake and outflow stream of a small Finnish catchment between 1990 and 2003. Both production in the catchment and mineralization in the lake controlled [DOC] in the lake. Concentrations in the catchment outflow were controlled by rates of DOC production in the surrounding organic soils. The INCA-C simulation results were compared to those obtained using artificial neural networks (ANN). In general, "black box" ANN models provide better fits to observed data but process-based models can identify the mechanism responsible for the observed pattern. A statistically significant increase was observed in both INCA-C modelled and measured annual average [DOC] in the lake. This suggests that some of the observed increase in surface water [DOC] is caused by climate-related processes operating in the lake and catchment. However, a full understanding of surface water [DOC] dynamics can only come from catchment-scale process-based models linking the effects of changing climate and deposition on aquatic and terrestrial environments

The impacts of future climate change and sulphur emission reductions on acidification recovery at Plastic Lake, Ontario

International audienceClimate-induced drought events have a significant influence on sulphate export from forested catchments in central Ontario, subsequently delaying the recovery of surface waters from acidification. In the current study, a model chain that employed a statistical downscaling model, a hydrological model and two hydrochemical models was used to forecast the chemical recovery of Plastic Lake sub-catchment 1 (PC1) from acidification under proposed deposition reductions and the A2 emission scenario of the Intergovernmental Panel on Climate Change. Any predicted recovery in stream acid neutralising capacity and pH owing to deposition reductions were clearly offset by large acid effluxes from climate-induced drought events. By 2100, ANC is predicted to show large variations ranging between 10 and ?30 ?molc L?1. Similarly, predicted pH in 2100 is lower (>0.05 of a pH unit) than the value simulated for 2000 (pH 4.35). Despite emission reductions, the future scenario paints a bleak picture of reacidification at PC1 to levels commensurate with those of the late 1970s. The principal process behind this reacidification is the oxidation of previously stored (reduced) sulphur compounds in wetlands during periods of low-flow (or drought), with subsequent efflux of sulphate upon re-wetting. Simulated catchment runoff under the A2 emissions scenario predictes increased intensity and frequency of low-flow events from approximately 2030 onwards. The Integrated Catchments model for Carbon indicated that stream DOC concentrations at PC1 will also increase under the future climate scenario, with temperature being the principal driver. Despite the predicted (significant) increase in DOC, pH is not predicted to further decline (beyond the climate-induced oxidation scenario), instead pH shows greater variability throughout the simulation. As echoed by many recent studies, hydrochemical models and model frameworks need to incorporate the drivers and mechanisms (at appropriate time-scales) that affect the key biogeochemical processes to reliably predict the impacts of climate change

Paediatric nonbronchoscopic bronchoalveolar lavage: Overview and recommendations for clinical practice

NB-BAL is an effective procedure for the diagnosis of pulmonary disease processes in ventilated infants and children. This procedure is, however, not without risks to both patients and staff. Numerous complications of NB-BAL exist, with hypoxia being the most common. As a result, care should be taken in performing NB-BAL on haemodynamically unstable patients; patients with coagulation defects; and patients with cardiac or brain abnormalities. This paper presents an overview of paediatric nonbronchoscopic bronchoalveolar lavage (NB-BAL) including: the rationale for NB-BAL; the complications associated with the procedure; indications and contraindications. It also recommends an evidence-based clinical guideline for performing the procedure in the paediatric intensive care unit. By following the NB-BAL guidelines presented in this paper, one can ensure that an effective specimen is obtained from the lower respiratory tract, whilst minimising the risk to the patient

Symmetric arrangement of mitochondria:plasma membrane contacts between adjacent photoreceptor cells regulated by Opa1

Mitochondria are known to play an essential role in photoreceptor function and survival that enables normal vision. Within photoreceptors, mitochondria are elongated and extend most of the inner-segment length, where they supply energy for protein synthesis and the phototransduction machinery in the outer segment, as well as acting as a calcium store. Here, we examined the arrangement of the mitochondria within the inner segment in detail using three-dimensional (3D) electron microscopy techniques and show they are tethered to the plasma membrane in a highly specialized arrangement. Remarkably, mitochondria and their cristae openings align with those of neighboring inner segments. The pathway by which photoreceptors meet their high energy demands is not fully understood. We propose this to be a mechanism to share metabolites and assist in maintaining homeostasis across the photoreceptor cell layer. In the extracellular space between photoreceptors, Müller glial processes were identified. Due to the often close proximity to the inner-segment mitochondria, they may, too, play a role in the inner-segment mitochondrial arrangement as well as metabolite shuttling. OPA1 is an important factor in mitochondrial homeostasis, including cristae remodeling; therefore, we examined the photoreceptors of a heterozygous Opa1 knockout mouse model. The cristae structure in the Opa1+/− photoreceptors was not greatly affected, but the mitochondria were enlarged and had reduced alignment to neighboring inner-segment mitochondria. This indicates the importance of key regulators in maintaining this specialized photoreceptor mitochondrial arrangement

PERSiST: a flexible rainfall-runoff modelling toolkit for use with the INCA family of models

Runoff generation processes and pathways vary widely between catchments. Credible simulations of solute and pollutant transport in surface waters are dependent on models which facilitate appropriate, catchment-specific representations of perceptual models of the runoff generation process. Here, we present a flexible, semi-distributed landscape-scale rainfall-runoff modelling toolkit suitable for simulating a broad range of user-specified perceptual models of runoff generation and stream flow occurring in different climatic regions and landscape types. PERSiST (the Precipitation, Evapotranspiration and Runoff Simulator for Solute Transport) is designed for simulating present-day hydrology; projecting possible future effects of climate or land use change on runoff and catchment water storage; and generating hydrologic inputs for the Integrated Catchments (INCA) family of models. PERSiST has limited data requirements and is calibrated using observed time series of precipitation, air temperature and runoff at one or more points in a river network. Here, we apply PERSiST to the river Thames in the UK and describe a Monte Carlo tool for model calibration, sensitivity and uncertainty analysi

Photoreceptor phagosome processing defects and disturbed autophagy in retinal pigment epithelium of Cln3Δex1-6 mice modelling juvenile neuronal ceroid lipofuscinosis (Batten disease)

Retinal degeneration and visual impairment are the first signs of juvenile neuronal ceroid lipofuscinosis caused by CLN3 mutations, followed by inevitable progression to blindness. We investigated retinal degeneration in Cln3Δex1-6 null mice, revealing classic ‘fingerprint’ lysosomal storage in the retinal pigment epithelium (RPE), replicating the human disease. The lysosomes contain mitochondrial F0-ATP synthase subunit c along with undigested membranes, indicating a reduced degradative capacity. Mature autophagosomes and basal phagolysosomes, the terminal degradative compartments of autophagy and phagocytosis, are also increased in Cln3Δex1-6 RPE, reflecting disruption to these key pathways that underpin the daily phagocytic turnover of photoreceptor outer segments (POS) required for maintenance of vision. The accumulated autophagosomes have post-lysosome fusion morphology, with undigested internal contents visible, while accumulated phagosomes are frequently docked to cathepsin D-positive lysosomes, without mixing of phagosomal and lysosomal contents. This suggests lysosome-processing defects affect both autophagy and phagocytosis, supported by evidence that phagosomes induced in Cln3Δex1-6-derived mouse embryonic fibroblasts have visibly disorganized membranes, unprocessed internal vesicles and membrane contents, in addition to reduced LAMP1 membrane recruitment. We propose that defective lysosomes in Cln3Δex1-6 RPE have a reduced degradative capacity that impairs the final steps of the intimately connected autophagic and phagocytic pathways that are responsible for degradation of POS. A build-up of degradative organellar by-products and decreased recycling of cellular materials is likely to disrupt processes vital to maintenance of vision by the RPE

The intercalated BSc (Med) Honours/MB ChB and integrated MB ChB/PhD tracks at the University of Cape Town: Models for a national medical student research training programme

The Faculty of Health Sciences at the University of Cape Town is addressing the shortage of clinician-scientists in South Africa by introducing two research training tracks in parallel with the professional MB ChB programme, namely the intercalated BSc (Med) Hons/MB ChB track and the integrated MB ChB/PhD track. The BSc (Med) Hons/MB ChB track is available to MB ChB students who have completed the first two years of study. The track comprises a course in Molecular Medicine given concurrently with the MB ChB third-year curriculum, followed by a BSc (Med) Hons as a ‘year out’ of MB ChB. Subsequently students may enrol into the integrated MB ChB/PhD track that enables them to undertake a PhD concurrently with MB ChB studies, which will be spread over additional years, or alternatively to undertake a PhD after completion of the MB ChB. These tracks, which were launched in 2011, represent an opportunity to train a new cadre of young African clinician-scientists at the undergraduate level.

Methamphetamine enhances caveolar transport of therapeutic agents across the rodent blood-brain barrier

Summary The blood-brain barrier (BBB) restricts clinically relevant accumulation of many therapeutics in the CNS. Low-dose methamphetamine (METH) induces fluid-phase transcytosis across BBB endothelial cells in vitro and could be used to enhance CNS drug delivery. Here, we show that low-dose METH induces significant BBB leakage in rodents ex vivo and in vivo. Notably, METH leaves tight junctions intact and induces transient leakage via caveolar transport, which is suppressed at 4°C and in caveolin-1 (CAV1) knockout mice. METH enhances brain penetration of both small therapeutic molecules, such as doxorubicin (DOX), and large proteins. Lastly, METH improves the therapeutic efficacy of DOX in a mouse model of glioblastoma, as measured by a 25% increase in median survival time and a significant reduction in satellite lesions. Collectively, our data indicate that caveolar transport at the adult BBB is agonist inducible and that METH can enhance drug delivery to the CNS