120 research outputs found

    Ranging patterns and site fidelity of Snubfin Dolphins in Yawuru Nagulagun/Roebuck Bay, Western Australia

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    For long-lived species such as marine mammals, having sufficient data on ranging patterns and space use in a timescale suitable for population management and conservation can be difficult. Yawuru Nagulagun/Roebuck Bay in the northwest of Western Australia supports one of the largest known populations of Australian snubfin dolphins (Orcaella heinsohni)—a species with a limited distribution, vulnerable conservation status, and high cultural value. Understanding the species’ use of this area will inform management for the long-term conservation of this species. We combined 11 years of data collected from a variety of sources between 2007 and 2020 to assess the ranging patterns and site fidelity of this population. Ranging patterns were estimated using minimum convex polygons (MCPs) and fixed kernel densities (weighted to account for survey effort) to estimate core and representative areas of use for both the population and for individuals. We estimated the population to range over a small area within the bay (103.05 km2). The Mean individual representative area of use (95% Kernel density contour) was estimated as 39.88 km2 (± 32.65 SD) and the Mean individual core area of use (50% Kernel density contour) was estimated as 21.66 km2 (±18.85 SD) with the majority of sightings located in the northern part of the bay less than 10 km from the coastline. Most individuals (56%) showed moderate to high levels of site fidelity (i.e., part-time or long-term residency) when individual re-sight rates were classified using agglomerative hierarchical clustering (AHC). These results emphasize the importance of the area to this vulnerable species, particularly the area within the Port of Broome that has been identified within the population’s core range. The pressures associated with coastal development and exposure to vessel traffic, noise, and humans will need to be considered in ongoing management efforts. Analyzing datasets from multiple studies and across time could be beneficial for threatened species where little is known on their ranging patterns and site fidelity. Combined datasets can provide larger sample sizes over an extended period of time, fill knowledge gaps, highlight data limitations, and identify future research needs to be considered with dedicated studies

    Impaired Progesterone-Responsiveness of CD11c+ Dendritic Cells Affects the Generation of CD4+ Regulatory T Cells and Is Associated With Intrauterine Growth Restriction in Mice

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    Up to 10% of pregnancies in Western societies are affected by intrauterine growth restriction (IUGR). IUGR reduces short-term neonatal survival and impairs long-term health of the children. To date, the molecular mechanisms involved in the pathogenesis of IUGR are largely unknown, but the failure to mount an adequate endocrine and immune response during pregnancy has been proposed to facilitate the occurrence of IUGR. A cross talk between the pregnancy hormone progesterone and innate immune cell subsets such as dendritic cells (DCs) is vital to ensure adequate placentation and fetal growth. However, experimental strategies to pinpoint distinct immune cell subsets interacting with progesterone in vivo have long been limited. In the present study, we have overcome this limitation by generating a mouse line with a specific deletion of the progesterone receptor (PR) on CD11c+ DCs. We took advantage of the cre/loxP system and assessed reproductive outcome in Balb/c-mated C57Bl/6 PRflox/floxCD11ccre/wt females. Balb/c-mated C57Bl/6 PRwt/wtCD11ccre/wt females served as controls. In all dams, fetal growth and development, placental function and maternal immune and endocrine adaptation were evaluated at different gestational time points. We observed a significantly reduced fetal weight on gestational day 13.5 and 18.5 in PRflox/floxCD11ccre/wt females. While frequencies of uterine CD11c+ cells were similar in both groups, an increased frequency of co-stimulatory molecules was observed on DCs in PRflox/floxCD11ccre/wt mice, along with reduced frequencies of CD4+ FoxP3+ and CD8+ CD122+ regulatory T (Treg) cells. Placental histomorphology revealed a skew toward increased junctional zone at the expense of the labyrinth in implantations of PRflox/floxCD11ccre/wt females, accompanied by increased plasma progesterone concentrations. Our results support that DCs are highly responsive to progesterone, subsequently adapting to a tolerogenic phenotype. If such cross talk between progesterone and DCs is impaired, the generation of pregnancy-protective immune cells subsets such as CD4+ and CD8+ Treg cells is reduced, which is associated with poor placentation and IUGR in mice

    Shallow and Deep Groundwater Moderate Methane Dynamics in a High Arctic Glacial Catchment

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    Glacial groundwater can mobilize deep-seated methane from beneath glaciers and permafrost in the Arctic, leading to atmospheric emissions of this greenhouse gas. We present a temporal, hydro-chemical dataset of methane-rich groundwater collected during two melt seasons from a high Arctic glacial forefield to explore the seasonal dynamics of methane emissions. We use methane and ion concentrations and the isotopic composition of water and methane to investigate the sources of groundwater and the origin of the methane that the groundwater transports to the surface. Our results suggest two sources of groundwater, one shallow and one deep, which mix, and moderate methane dynamics. During summer, deep methane-rich groundwater is diluted by shallow oxygenated groundwater, leading to some microbial methane oxidation prior to its emergence at the surface. Characterization of the microbial compositions in the groundwater shows that microbial activity is an important seasonal methane sink along this flow-path. In the groundwater pool studied, we found that potential methane emissions were reduced by an average of 29% (±14%) throughout the summer due to microbial oxidation. During winter, deep groundwater remains active while many shallow systems shut down due to freezing, reducing subsurface methane oxidation, and potentially permitting larger methane emissions. Our results suggest that ratios of the different groundwater sources will change in the future as aquifer capacities and recharge volumes increase in a warming climate

    Metabolic Network Analysis Reveals Altered Bile Acid Synthesis and Metabolism in Alzheimer\u27s Disease.

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    Increasing evidence suggests Alzheimer\u27s disease (AD) pathophysiology is influenced by primary and secondary bile acids, the end product of cholesterol metabolism. We analyze 2,114 post-mortem brain transcriptomes and identify genes in the alternative bile acid synthesis pathway to be expressed in the brain. A targeted metabolomic analysis of primary and secondary bile acids measured from post-mortem brain samples of 111 individuals supports these results. Our metabolic network analysis suggests that taurine transport, bile acid synthesis, and cholesterol metabolism differ in AD and cognitively normal individuals. We also identify putative transcription factors regulating metabolic genes and influencing altered metabolism in AD. Intriguingly, some bile acids measured in brain tissue cannot be explained by the presence of enzymes responsible for their synthesis, suggesting that they may originate from the gut microbiome and are transported to the brain. These findings motivate further research into bile acid metabolism in AD to elucidate their possible connection to cognitive decline

    De novo mutations in SMCHD1 cause Bosma arhinia microphthalmia syndrome and abrogate nasal development

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    Bosma arhinia microphthalmia syndrome (BAMS) is an extremely rare and striking condition characterized by complete absence of the nose with or without ocular defects. We report here that missense mutations in the epigenetic regulator SMCHD1 mapping to the extended ATPase domain of the encoded protein cause BAMS in all 14 cases studied. All mutations were de novo where parental DNA was available. Biochemical tests and in vivo assays in Xenopus laevis embryos suggest that these mutations may behave as gain-of-function alleles. This finding is in contrast to the loss-of-function mutations in SMCHD1 that have been associated with facioscapulohumeral muscular dystrophy (FSHD) type 2. Our results establish SMCHD1 as a key player in nasal development and provide biochemical insight into its enzymatic function that may be exploited for development of therapeutics for FSHD

    TaReCa – Cascade utilization of horticultural biomass for a resource efficient production of valuable bioactive substances

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    Viele pflanzliche SekundĂ€rmetabolite haben antioxidative oder andere bioaktive Eigenschaften, weshalb sie einerseits wichtige Bestandteile der menschlichen ErnĂ€hrung sind, andererseits aber auch als pharmazeutische Verbindungen oder als Substrat fĂŒr die chemische Synthese von bioaktiven Substanzen verwendet werden. Pflanzen induzieren die Produktion solcher nutzbaren SekundĂ€rmetabolite wie z.B. Flavonoiden als Reaktion auf abiotischen Stress. Die Produktion von GemĂŒse und FrĂŒchten in GewĂ€chshĂ€usern hinterlĂ€sst große Mengen an ungenutzter pflanzlicher Biomasse, welche eine potentielle Ressource fĂŒr die Gewinnung wertvoller Metabolite darstellt. Durch eine kaskadenartige Verwendung von Gartenbaukulturen zur Produktion von FrĂŒchten und GemĂŒse mit einer anschließenden Gewinnung hochwertiger Substanzen aus der verbleibenden Restbiomasse wĂŒrde ein erheblicher Mehrwert generiert. Das Projekt TaReCa bearbeitet die Entwicklung einer maßgeschneiderten Kaskadenverwertung von Paprikapflanzen-Restbiomasse aus dem Gartenbau. Dabei soll der pflanzliche SekundĂ€rmetabolismus durch spezifische abiotische Stressbedingungen nach der Fruchternte gezielt induziert werden, um die Konzentrationen der Zielmetaboliten zu steigern. Durch umweltfreundliche und wirtschaftliche Extraktionsprozesse und eine anschließende Verwertung des verbleibenden Pflanzenmaterials in einer Bioraffinerie wird die Wertschöpfungskette erweitert. Eine Analyse der Anwendungsgebiete sowie Untersuchungen zur Akzeptanz der induzierten Inhaltsstoffe, Prozesse und Technologien werden helfen, das Marktpotenzial der Restbiomasse fĂŒr die Nutzung in Kaskaden zu evaluieren. Die maßgeschneiderte Nutzung von Gartenbaubiomasse durch Lebensmittelproduktion, Extraktion bioaktiver SekundĂ€rmetabolite und Bioraffinerien kann wirtschaftlich relevante, biobasierte Produkte fĂŒr industrielle Anwendungen erzeugen und somit zur Entwicklung einer nachhaltigen, effizienten und integrierten Bioökonomie beitragen, ohne mit der Lebensmittelproduktion zu konkurrieren.Many plant secondary metabolites have antioxidant or pharmaceutically relevant properties, which makes them important components of the human diet, but also as pharmaceutical compounds or for the chemical synthesis of bioactive substances. Plants induce the production of secondary metabolites, e.g. flavonoids in response to environmental stress stimuli. The production of vegetables and fruits in greenhouses leaves huge amounts of so far under-utilized biomass after fruit harvest, which is a potential source for production of valuable metabolites. A cascade utilization of horticultural crops to produce fruits and vegetables with subsequent extraction of high quality compounds would generate significant added value. The project TaReCa is working on the development of a tailored cascade utilization of bell pepper plant residues from horticulture. The secondary metabolism will be induced by specific abiotic stress treatments after the last fruit harvest, in order to increase the concentrations of the target metabolites. Eco-friendly and economical extraction processes and subsequent utilization of the remaining plant material in a biorefinery will expand the value chain. An analysis of the application areas as well as studies on the acceptance of the induced ingredients, processes and technologies will help to evaluate the market potential of the residual biomass for the proposed cascaded use. The tailored utilization of horticultural biomass in food production, extraction of bioactive secondary metabolites and biorefineries can produce economically relevant bio-based products for industrial applications and thus contribute to the development of a sustainable, efficient and integrated bioeconomy without competing with food production

    Vitamin D Receptor Deficiency and Low Vitamin D Diet Stimulate Aortic Calcification and Osteogenic Key Factor Expression in Mice

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    Low levels of 25-hydroxy vitamin D (25(OH)D) are associated with cardiovascular diseases. Herein, we tested the hypothesis that vitamin D deficiency could be a causal factor in atherosclerotic vascular changes and vascular calcification. Aortic root sections of vitamin D receptor knockout (VDR−/−) mice that were stained for vascular calcification and immunostained for osteoblastic differentiation factors showed more calcified areas and a higher expression of the osteogenic key factors Msx2, Bmp2, and Runx2 than the wild-type mice (P<0.01). Data from LDL receptor knockout (LDLR−/−) mice that were fed western diet with either low (50 IU/kg), recommended (1,000 IU/kg), or high (10,000 IU/kg) amounts of vitamin D3 over 16 weeks revealed increasing plasma concentrations of 25(OH)D (P<0.001) with increasing intake of vitamin D, whereas levels of calcium and phosphorus in plasma and femur were not influenced by the dietary treatment. Mice treated with the low vitamin D diet had more calcified lesions and a higher expression of Msx2, Bmp2, and Runx2 in aortic roots than mice fed recommended or high amounts of vitamin D (P<0.001). Taken together, these findings indicate vitamin D deficiency as a risk factor for aortic valve and aortic vessel calcification and a stimulator of osteogenic key factor expression in these vascular areas

    Aberrant Receptor-Mediated Endocytosis of Schistosoma mansoni Glycoproteins on Host Lipoproteins

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    BACKGROUND: Bilharzia is one of the major parasitic infections affecting the public health and socioeconomic circumstances in (sub) tropical areas. Its causative agents are schistosomes. Since these worms remain in their host for decades, they have developed mechanisms to evade or resist the immune system. Like several other parasites, their surface membranes are coated with a protective layer of glycoproteins that are anchored by a lipid modification. METHODS AND FINDINGS: We studied the release of glycosyl-phosphatidylinositol (GPI)-anchored proteins of S. mansoni and found them in the circulation associated with host lipoprotein particles. Host cells endocytosed schistosomal GPI-anchored proteins via their lipoprotein receptor pathway, resulting in disturbed lysosome morphology. In patients suffering from chronic schistosomiasis, antibodies attacked the parasite GPI-anchored glycoproteins that were associated with the patients' own lipoprotein particles. These immunocomplexes were endocytosed by cells carrying an immunoglobulin-Fc receptor, leading to clearance of lipoproteins by the immune system. As a consequence, neutral lipids accumulated in neutrophils of infected hamsters and in human neutrophils incubated with patient serum, and this accumulation was associated with apoptosis and reduced neutrophil viability. Also, Trypanosoma brucei, the parasite that causes sleeping sickness, released its major GPI-anchored glycoprotein VSG221 on lipoprotein particles, demonstrating that this process is generalizable to other pathogens/parasites. CONCLUSIONS: Transfer of parasite antigens to host cells via host lipoproteins disrupts lipid homeostasis in immune cells, promotes neutrophil apoptosis, may result in aberrant antigen presentation in host cells, and thus cause an inefficient immune response against the pathogen
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