Hyaluronan Export through Plasma Membranes Depends on Concurrent K+ Efflux by Kir Channels

Hyaluronan is synthesized within the cytoplasm and exported into the extracellular matrix through the cell membrane of fibroblasts by the MRP5 transporter. In order to meet the law of electroneutrality, a cation is required to neutralize the emerging negative hyaluronan charges. As we previously observed an inhibiting of hyaluronan export by inhibitors of K+ channels, hyaluronan export was now analysed by simultaneously measuring membrane potential in the presence of drugs. This was done by both hyaluronan import into inside-out vesicles and by inhibition with antisense siRNA. Hyaluronan export from fibroblast was particularly inhibited by glibenclamide, ropivacain and BaCl2 which all belong to ATP-sensitive inwardly-rectifying Kir channel inhibitors. Import of hyaluronan into vesicles was activated by 150 mM KCl and this activation was abolished by ATP. siRNA for the K+ channels Kir3.4 and Kir6.2 inhibited hyaluronan export. Collectively, these results indicated that hyaluronan export depends on concurrent K+ efflux

Statistical Analysis of the Processes Controlling Choline and Ethanolamine Glycerophospholipid Molecular Species Composition

The regulation and maintenance of the cellular lipidome through biosynthetic, remodeling, and catabolic mechanisms are critical for biological homeostasis during development, health and disease. These complex mechanisms control the architectures of lipid molecular species, which have diverse yet highly regulated fatty acid chains at both the sn1 and sn2 positions. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) serve as the predominant biophysical scaffolds in membranes, acting as reservoirs for potent lipid signals and regulating numerous enzymatic processes. Here we report the first rigorous computational dissection of the mechanisms influencing PC and PE molecular architectures from high-throughput shotgun lipidomic data. Using novel statistical approaches, we have analyzed multidimensional mass spectrometry-based shotgun lipidomic data from developmental mouse heart and mature mouse heart, lung, brain, and liver tissues. We show that in PC and PE, sn1 and sn2 positions are largely independent, though for low abundance species regulatory processes may interact with both the sn1 and sn2 chain simultaneously, leading to cooperative effects. Chains with similar biochemical properties appear to be remodeled similarly. We also see that sn2 positions are more regulated than sn1, and that PC exhibits stronger cooperative effects than PE. A key aspect of our work is a novel statistically rigorous approach to determine cooperativity based on a modified Fisher's exact test using Markov Chain Monte Carlo sampling. This computational approach provides a novel tool for developing mechanistic insight into lipidomic regulation

Hantaviren und Nagetiere in Deutschland: Das Netzwerk „Nagetier-übertragene Pathogene”

ZusammenfassungHantavirus-Infektionen sind in Deutschland seit etwa 25 Jahren bekannt. Die durchschnittliche Antikörperprävalenz in der Bevölkerung liegt bei ca. 1 bis 2%. Nach Einführung der Meldepflicht im Jahr 2001 sind jährlich durchschnittlich etwa 70 bis 240 Fälle gemeldet worden. Im Jahr 2005 und insbesondere im Jahr 2007 ist jedoch ein deutlicher Anstieg der Zahl der gemeldeten Fälle registriert worden. Die am meisten betroffenen Regionen lagen in den Bundesländern Baden-Württemberg, Bayern, Nordrhein-Westfalen und Niedersachsen. Im Gegensatz zur gut dokumentierten Situation beim Menschen ist die Kenntnis der geografischen Verbreitung und Häufigkeit von Hantavirus-Infektionen in den Nagetier-Reservoiren und deren Schwankungen sehr begrenzt. Aus diesem Grund wurde in Deutschland das Netzwerk „Nagetier-übertragene Pathogene“ etabliert, das interdisziplinäre Untersuchungen zur Nagetier-Populationsdynamik, Prävalenz und Evolution von Hantaviren und anderen Nagetier-assoziierten Zoonoseerregern und den zugrunde liegenden Mechanismen sowie deren Auswirkungen auf die Häufigkeit humaner Infektionen erlaubt. Ein Monitoring von Hantaviren in Nagetieren wurde in Endemiegebieten (Baden-Württemberg, Bayern, Nordrhein-Westfalen, Niedersachsen) und Regionen mit einer geringen Zahl humaner Fälle (Mecklenburg-Vorpommern, Brandenburg, Sachsen, Sachsen-Anhalt, Thüringen, Schleswig-Holstein, Hessen, Rheinland-Pfalz) initiiert. Insgesamt wurde eine breite geographische Verbreitung des Puumalavirus (PUUV) in Rötelmäusen und des Tulavirus in Microtus-Mäusen dokumentiert. Dobrava-Belgrad-Virus-positive Apodemus-Mäuse wurden bisher ausschließlich in Brandenburg, Mecklenburg-Vorpommern und Niedersachsen gefunden. In den Hantavirus-Ausbruchsgebieten in Baden-Württemberg, Bayern, Nordrhein-Westfalen und Niedersachsen wurde bei Rötelmäusen eine hohe PUUV-Prävalenz beobachtet. Initiale Longitudinalstudien in Nordrhein-Westfalen (Stadt Köln), Bayern (Niederbayern) und Niedersachsen (ländliche Region bei Osnabrück) zeigten ein stabiles Vorkommen des PUUV in den Rötelmaus-Populationen. Neben den Untersuchungen zu Hantaviren ist auch mit Studien zum Vorkommen von anderen Nagetier-assoziierten Zoonoseerregern begonnen worden. Die begonnenen Longitudinalstudien werden Schlussfolgerungen zur Evolution von Hantaviren und anderen Nagetierassoziierten Erregern und zu Veränderungen in deren Häufigkeit und Verbreitung ermöglichen. Diese Untersuchungen werden zukünftig eine verbesserte Risikoabschätzung für die Gefährdung der Bevölkerung ermöglichen, die auch die möglichen zukünftigen Klimawandel-bedingten Veränderungen in der Epidemiologie Nagetier-assoziierter Zoonoseerreger berücksichtigt

Reviewing the use of resilience concepts in forest sciences

Purpose of the review Resilience is a key concept to deal with an uncertain future in forestry. In recent years, it has received increasing attention from both research and practice. However, a common understanding of what resilience means in a forestry context, and how to operationalise it is lacking. Here, we conducted a systematic review of the recent forest science literature on resilience in the forestry context, synthesising how resilience is defined and assessed. Recent findings Based on a detailed review of 255 studies, we analysed how the concepts of engineering resilience, ecological resilience, and social-ecological resilience are used in forest sciences. A clear majority of the studies applied the concept of engineering resilience, quantifying resilience as the recovery time after a disturbance. The two most used indicators for engineering resilience were basal area increment and vegetation cover, whereas ecological resilience studies frequently focus on vegetation cover and tree density. In contrast, important social-ecological resilience indicators used in the literature are socio-economic diversity and stock of natural resources. In the context of global change, we expected an increase in studies adopting the more holistic social-ecological resilience concept, but this was not the observed trend. Summary Our analysis points to the nestedness of these three resilience concepts, suggesting that they are complementary rather than contradictory. It also means that the variety of resilience approaches does not need to be an obstacle for operationalisation of the concept. We provide guidance for choosing the most suitable resilience concept and indicators based on the management, disturbance and application context

Recreating peatland initiation conditions: methods for reclaiming peatlands in Alberta's oil sands region

2014 Spring.Includes bibliographical references.Northern Alberta's oil sands deposit is the largest in the world and mining operations remove vast areas of upland forests and peatland ecosystems. Reclaiming peatland ecosystems is challenging as it takes thousands of years to reestablish peat soils to pre-disturbance extents. Practical approaches that are easy to implement are required to reclaim the tens of thousands of peatland hectares that have been lost to mining activities. My research focuses on developing reclamation methods that recreate peatland initiation conditions on mineral soil and apply assisted succession techniques by introducing mosses, plants and woody cover. I evaluated the regenerative abilities of five common fen mosses introduced in a 1:10 mixture to clay loam mineral soil. To evaluate optimal hydrologic conditions for moss species establishment, I tested four water levels below the soil surface (0, -10, -20, and -30 cm). I recreated plant communities and microclimates similar to those found during peatland initiation to determine those that increased moss species establishment by comparing cover treatments of herbaceous plants, woody plants, and WoodStraw® (wood-strand) mulch. After two seasons of growth, fen mosses established and grew to an average of 20 percent cover on mineral soils. Total moss cover was not significantly different between 0cm and -30 cm water levels but species distribution was as depth to the water table was the most important factor influencing establishment. Drepanocladus aduncus was most common when the water level was 0 cm and Aulacomnium palustre was most common in the -30 cm water level. Tomentypnum nitens had five times greater cover than any other moss. Moss species cover and height was greatest under herbaceous plants and at 0 cm water level. Wood-strand mulch reduced the cover of salt that precipitated on the soil surface, which also increased as the water table deepened. Implications to peatland reclamation include selecting a mixture of mosses to adapt to chemical and hydrologic variations and planting herbaceous plants and or applying wood-strand mulch to improve moss establishment on mineral soil. Peatlands may take thousands of years to develop, but reclaiming a carbon-accumulating ecosystem and establishing the foundations for peatland succession is possible. The applications described here provide economical and practical strategies to reconstruct pre-existing peatland ecosystems in Alberta's oil sands region

A Vegetation Assessment of the Kearl Treatment Wetland following Exposure to Oil Sands Process-Affected Water

Treatment wetlands have emerged as a potential option for the treatment of oil sands process-affected water (OSPW). The long-term viability of these treatment systems relies, in part, on the health and productivity of wetland vegetation. The aim of this study is to investigate the physiological and community-level effects on wetland vegetation at the Kearl Treatment Wetland (KTW) following exposure to different OSPW sources. Annual vegetation assessments were performed during 2016–2021 to monitor species composition, total percent cover, species richness, species morphology (plant stem density, leaf length, and leaf width), and plant vigor in the KTW. Cattail was found to dominate the deep-water zones whereas water sedge was found to dominate the shallow-water zones of the wetland. Species richness in the KTW decreased with time which is typical of constructed wetlands receiving industrial effluents. No changes in plant stem density of cattails or water sedge were observed; however, leaf length decreased from 2019 to 2021, and leaf width decreased from 2020 to 2021. Plant vigor ratings increased in the KTW each year suggesting that the vegetation does not show any major signs of phytotoxicity from OSPW exposure. These results demonstrate the complex dynamics and resiliency of the vegetative community in treatment wetlands, but continued efforts to monitor plant uptake and accumulation are needed to fully assess the phytotoxic effects of OSPW exposure

A Vegetation Assessment of the Kearl Treatment Wetland following Exposure to Oil Sands Process-Affected Water

Treatment wetlands have emerged as a potential option for the treatment of oil sands process-affected water (OSPW). The long-term viability of these treatment systems relies, in part, on the health and productivity of wetland vegetation. The aim of this study is to investigate the physiological and community-level effects on wetland vegetation at the Kearl Treatment Wetland (KTW) following exposure to different OSPW sources. Annual vegetation assessments were performed during 2016–2021 to monitor species composition, total percent cover, species richness, species morphology (plant stem density, leaf length, and leaf width), and plant vigor in the KTW. Cattail was found to dominate the deep-water zones whereas water sedge was found to dominate the shallow-water zones of the wetland. Species richness in the KTW decreased with time which is typical of constructed wetlands receiving industrial effluents. No changes in plant stem density of cattails or water sedge were observed; however, leaf length decreased from 2019 to 2021, and leaf width decreased from 2020 to 2021. Plant vigor ratings increased in the KTW each year suggesting that the vegetation does not show any major signs of phytotoxicity from OSPW exposure. These results demonstrate the complex dynamics and resiliency of the vegetative community in treatment wetlands, but continued efforts to monitor plant uptake and accumulation are needed to fully assess the phytotoxic effects of OSPW exposure